Note: Descriptions are shown in the official language in which they were submitted.
METHOD AND TARGET FOR SPUTTER DEPOSITING THIN FILMS
Technical Field
This invention relates to sputter depositing of
thin films, such as for thin film magnetic recording
discs, and to methods and apparatus fo:r manufacturing
such discs. More particularly, the invention relates to
a composite source target and method for fabricating by
RF diode sputtering a thin film magnetic disc having a
magnetic layer comprising at least two materials, such
as platinum and cobalt and having a radial coercivity
gradient~
As disclosed in U.S. Patent 4,610,911 of James E.
Opfer and Bangalore Natarajan entitled "Thin Film
Magnetic Recording Medial' issued September 9, 1986 and
assigned to the instant assignee, the magnetic
properties of a thin film magnetic recording disc having
a cobalt-platinum magnetic layer with selectively
desirable properties may be established in accordance
with the thickness of an underlying chromium film, the
thickness of the cobalt-platinum film, and the
concentration of platinum in the cobalt-platinum film.
It is known that the chemical composition of a
sputtered film i5 usually the same as that of the
cathode (target) from which it is sputtered. See
Handbook of Thin Film Technoloay edited by L.I. Maissel
and R. Glang and published by McGraw-Hill Book Co., New
York, New York (1970) at pages 3-28 and 4-39. Thus, to
sputter, for example, a cobalt-platinum film containing
about three percent platinum, the target would be a
homogeneous composition of cobalt and platinum with the
concentration of platinum in the target being about
three percent. Alternatively, on page 3-29 of this
~,," ~k
la
text, it is suggested that sputtered compositional or
alloy films can also be obtained by the use of multiple
targets, each of a single material, and that a wide
range of compositions can be obtained by independently
varying the sputtering rates of the targets.
There are, thus, two suggested known prior
techniques for providing sputtered compositional or
alloy films: utiliz-
,",~ ~ .
4~
zation of a homogeneous target o~ the material~, or utiliza-
tion of two or more independent target3, there being a sepa-
rate target for each material.
The first o~ the~s known techniques is limited and non-
variable in that the percentage composition of the various
material~ in the target i~ ~ixed and determine~ the
composition o~ the sputtered film. Furthermore, in th~ case
of cobalt and platinum, the cost of such a homogeneous target
is prohibitive. The second known technique, while permittin~
some versatility in the composition of the sputered film, by
varying tha targets, is also costly. Moreovar, problems are
encountered in this second approach ~hcn it is desired to
~imultaneously deposit films on opposite ~ides o~ a disc or
o~her substrate. For example, to ~putter a compo~ition of
two material~ on the two ~ide~ of ~uch a disc, at least four
targsts are required. ~hat i~, on~ 3et of two targets are
required at each ~ide of tho di~c ~or sputtering thereon.
one target o~ ~ach set being of a fir~t material and the
other target o~ each 8et b~ing of a ~econd material. In
addition, each of the four target~ would have to be provided
with a separate power supply ~ystem i~ each were to be
independently controllable. Independent control i~ nece~sary
in order to vary th~ ~putkering rate ~rom each target, and
thus the percentage compo~ition of each ~aterial.
Furthermor~, an arranse~nt of multiple, discrete targets
does not lend itsel~ to providing discs with magnetic films
o~ radially-varying cvercivity. As explain~d below, this
latter characteristic i8 particularly de irable for high
density recording on magnetia r~cording dlscs.
When di~cs are u~ed in a typical magnetlc recordiny
disc drive appliaction, the disc i~ annular, i5 rotated, and
a read-writ~ head i9 positioned to fly over the disc 90 as to
read or write on concQntric tracks on the disc. Tha speed o~
travel of the head, relativ~ to th~ di3c, i8 greater and the
head flie~ higher over the di3c when the head i~ reading or
writing onto outer track~ at outer diamet2rs of the disc in
comparison to inne~ tracks at inner diameters. I~ tha write
frequency is held constant, the recording density i~ much
tg
higher on tracks closer to th~ inner diameter of the disc in
comparison to the density on tracks toward the outer dia-
meter.
A~sum$ng a disc has a ~agnetic layer with a constant
radial coercivity, such as understood to be pro~ided by the
above de3cribed known techniques, writing on tracks near the
outer diameter of the disc i~ impoasible or unreliable unless
the writing current i~ increa~ed at ~uch outer diameter
tracks. Increased writing current i~ required because, as
explained above, the head ~lie~ abovQ tho disc surface as the
head move~ outwardly ~rom inner to outer tracks of the disc.
In order to write with a con~tant current, which in many ap-
plication~ i~ highly desirable, th~ radial coercivity o~ the
magn~tic layer on the diac must bs ad~u~ted 30 a~ to derrease
a~ the flying height of the head increa~e~. In other words,
th~ coercivity of th2 di~a should decrease with incr~a~ing
radial di~tances fro~ tha center o~ the disc.
The above described prior technique~ 8im~1y do not have
ox sugge~t the provi~ion of a magnetic layer with a radial
coercivity gradi~nt.
isclosure o~ Inven~io~
In accordance with ~he ~puttQring target and method of
the present in~Qntion, a ~puttering targst has a ~puttering
surface with ~ixat and ~cond r~gions of re~pectiv~ fir~t and
second material3. In th2 illu~tr~t~d preferr2d embod:LmQnt of
tha invantion, the targ~t co~prise~ a plat~ of a fir~t mate-
rial onto whlch is mountsd, in contact therewith, a member o~
a ~econd matrial o~ a pr~determin~d geometric shap~. By con-
trolling thQ area o~ th~ member o~ tha second material ex-
posed to a ~ub3trate ~uring sputtering, r~lative to the area
o~ the ~irst material expo~ed during ~putt~ring, the composi-
tion o~ the depo~ited lay~r ~putt~red ~rom the target may b~
d~termin~d.
More specifically, the ~irst ~aterial may aomprise a
disc Or cobalt, ~or axampl~, on ths 3ur~ace o~ which is
mount~d a ring o~ ~latinu~. By controlling the area o~ the
platinum ring which i3 expo~ed to a ~ub~trate during ~put-
tering, relative to the exposed area of cobalt, the percen-
tage composition o~ platinum in the ~puttered layer may be
controlled and determined. Thu~, to ~orm a cobalt-platinum
~ilm having a platinum content averaging about three percent,
the exposed area of the platlnum ring should constitute about
three percenk of the total sputtering target surface area,
the remaining ninety-~even percent o~ this area being cobalt.
Thi3 concentration o~ platinum i~ best determinad ~rom the
ratio of the width of the exposad platinum ring to the width
of the exposed cobalt areas.
As one mean~ of controlling th~ extent o~ the exposed
area of the platinum ring, the in~r perim~ter of tha platinum
ring is cla~ped in place on the cobalt disc by a cobalt cover
ring af~ixed to the cobalt disc. The cobalt di~c, platinum
ring, and cobalt co~er ring ~rQ concQntric with one another.
In addit1on, in on~ sp~cific for~ ~hown, the outside dia~eter
of the cobalt co~er ring i~ 1~8~ than the insid~ diameter of
the platinum ring- It will thu~ ba understood that the ex-
po~ed area of the pl atinu~ ring i~ directly deter~ined and
controlled by controllin~ the out~id~ deameter of the co~alt
coYer ring. That i8, the out~idQ d~ameter o~ tha cobalt
cover ring may be altered to achiov~ sxposure o~ any desired
ar0a of the platinum ring. Thu~, by decrea~ing the outside
dia~eter of the cobalt r~ng, tho ar~a o~ exposed platinu~ is
increased. Conver~ely, by increa~ing thQ outside diametsr o~
th~ cobalt covQr ring, the expo~ad area o~ the platinu~ ring
i~ d~crea~ed. Altornately, the cobalt cover ring may be
sized larger than the platinu~ ring. In thi~ case, th2 outer
perimeter or margin of the platinum ring i~ clamped to the
cobalt disc by the cover ring. Thu~, by controlling the
inner dlamater o~ ths cobalt cover ring, thQ exposed area of
the platinum i~ controlled.
Thus, tha sputt~ring ~urfa~e o~ the t~rg~t in this caqe
ls compri~od o~ only cobalt and pl~tinum. Mor~over, the ex-
tent o~ tha exposure o~ platinu~ is readily controlled and
pr~determined as desirQd. In addition, with ~uch a two mate-
rial compo~ita tar~t configuration, it is pos~ibla to depo-
sit a layer on a ~ubstrate with a percentage concentration of
~he Recond ~ub~tanca which varie~ in a controlled manner at
di~ferent location~ on thQ ~ub~trata. Thi~ variation is
achieved by varying thQ location o~ th~ axpo~d portions of
the member o~ the s~cond substance rQlativa to th~ ~xposed
portions of tha plat~ o~ the firat ~ub~tance. A~ a ~pecific
example, a~sume the abov~ described ring configuration and
that annular disc substrate~ are ~upported for planetary mo-
tion with thQ cent~r o~ ~otlon o~ th~ sub~trate~ nearly cen-
tered on tho c~nt~r o~ the ring. In thi~ ca~e, thQ platinum
concQntration in the sputtered layer variea in the ra~ial di-
rection. This variation in platinum concentration provides a
radial coercivity gr~di~nt ~ro~ inner to out~r diamet2rR of
the dis~ ~ub~trate~. Moreov~r, a8 thQ ~ize 0~ tho axposed
platinum ring i~ changed to shl~t the centQr o~ th~ exposed
ring away ~ro2 tha center o~ th~ sub~trat~, th~ radial coer-
civity gradi~nt i~ changsd~ Furthermore, the coorcivity gra-
di~nt which re~ult~ ~ro~ ~ pArticular platinu~ cobalt target
configuration ~ay bQ ~xparim~ntally determinad or b~ predic-
ted with 80~Q acouracy by ~ath2~atlcal modeling technigues.
Itis therefore an object of an aspect of the present invention to
provid~ an improvad spuktering targ~t and method for ~put-
tering at le~st two mat~ri~ls onto a ~ubatr~t~.
It is an object of an aspect of the present invention to
provido a sputter~ng ~ethod ~nd t~rgot ~or ~puttoring a ~hin
~il~ magnetic r~cording di~c with a layer o~ magnet~c materi-
al havinq a coercivity which Yarie~ in th~ radial direction
on th~ sub~trate.
It is an object of an aspect of the present invention to
provid~ an improve~ ~puttering ~thod and targst ~or sput-
tering a co~ponit~ layer on ~ ~ubstra~o in which tha porcen-
taga concentration o~ th~ co~ponente o~ ~h~ lay~r ara accu-
rately and o~iciently controll~d.
It is an object of an aspect of the present :invention to
provide a relativoly low coet sputtering targ~t and ~ethod
for sputtering a ~ilm o~ at lea~t ~wo conntituent materials
on a subetrate.
5a
Various aspects of the invention are as follows:
A target for sputter-depositing a magnetic layer
having a radial coercivity gradient on a substrate which
is moved relative to the target, said magnetic layer
having at least two constituent materials, said target
comprising:
a circular disc member of a first diameter
which is formed of a first constituent material;
a ring member having an inside diameter and an
outside diameter smaller than the first diameter,
the ring member being formed of a second
constituent material and being disposed on the base
member concentrically therewith; and
a clamping ring member having an outside
diameter which i6 less than the outside diameter of
the ring member and greater than the inside
diameter of the ring member, the clamping ring
member also having an inside diameter which is less
than the inside diameter of the ring member, the
clamping ring member being formed of ~he first
constituent material and being mounted to the base
member concentrically therewith and overlying a
portion of the inner perimeter margin of the ring
member so as to cIamp the ring member to the base
member whereby the sputtering surface of the target
comprises only the first and second constituent
materials in a predetermined ratio of exposed areas
thereof.
A method of depositing a magnetic layer having a
radial coercivity gradient on a planar substrate having
two sides comprising the steps of:
mounting a plurality of circular substrates
for planetary motion on a substrate carrier, said
substrate carrier being rotatable ~ t an axis
normal to an~ through its center, of said
substrates being mounted for rotary motion about
,~
~L29~L~43
5b
individual, circumferentially spaced axes which are
parallel to and radially displaced from the
substrate carrier axis of rotation, each of said
substrates being mounted in front of a circular
aperture in said substrate carrier, the diameter of
said aperture being greater than the diameter of
said substrates;
preparing a pair of sputtering targets, each
of said sputtering targets having a sputtering
surface comprises of a circular disc of a first
material and a concentric ring of a second material
mounted thereon, said pair of sputtering targets
being oriented in the vertical plane disposed in
spaced apart relationship having the sputtering
surfaces opposing;
disposing said substrate carrier in the
vertical plane between said opposing sputtering
surfaces such that each side of said substrates is
exposed to a sputtering surface; and
rotating said substrate carrier during
sputtering thereby imparting planetary motion to
said substrates about the axis of the substrate
carrier, the centers of said substrates being
substantially centered over said ring during such
planetary motion.
A method of sputter depositing a magnetic layer
having a radial coercivity gradient on a substrate
comprising the following steps:
exposing said substrate to a sputter target
having a sputtering surface comprised of a circular
disc of a first constituent material and a
concentric ring of a second constituent material
mounted thereon: and
simultaneously imparting planetary motion to
said substrate during sputter deposition of said
magnetic layer with the center of said substrate
~9~44~
5c
being substantially centered over said ring during
such planetary motion thereby varying the relative
concentration of said constituent materials in said
layer in radial directions from a predetermined
location on said substrate.
,... . .
L4~3
These and other feature~, ob~ 8Ct9 and advantage~ of the
present invention will become apparent with re~erence to the
following description and drawing~.
Bri~f Description o~ the Drawinas
Fig. 1 is a front elevational view o~ one e~bodiment of
a system for making thin film ~agn~tic discs and other prod-
ucts in accordance with the pre~ent invention;
Fig. 2 i~ a front i~ometric view o~ a load cha~ber of
Fig. 1;
Fig. 3 is a side elevational view of a load chamber of
Fig. 2, taken in the direction o~ llnes 3-3 of Fig. ~ to ~how
a ~ubstrate pass through opening through which sub3trates are
trancf~rred to an ad~oi~ing chamb~r of th~ ~y~tem;
Fig. 4 i~ a front iso~etric view o~ a dQposition cham-
ber hou~ing o~ ths ~yst~m;
FigO 5 i~ an i~ometric Yi~W 0~ a valve a~embly used to
interconnect the chambers o~ the 3y~tem o~ Fig. l;
Fig. 6 is a vertical sQctional view of a portion of th~
valv~ a88embly 0~ Fig. 5, tak0n along line~ 6-6 of Fig. 5;
Fig. 7 1~ a cros~ seational view 9~ the valvQ assembly
of Fig. 5, taken along lin~ 7-7 o~ Fig. 5:
Fig. 8 i~ a varti~al ~ctional view of a portion of the
valve a~e~bly o~ Fig. $, taken along lin~ 8-8 o~ Flg. 7 to
show a gate portion o~ the va}ve a~sembly;
Fig. 9 i~ a rear elevational view of a radio fre~uency
sputter deposition cha~ber o~ the sy~t~m of Fig. 1;
Fig. 10 i~ a vertical ~ectional view of the radio fre~
guency depo~ition chamber o~ ~ig. 9, taken along lines lO-lO
o~ Fig. 9;
Fig. 11 i~ a ~ront el~vatlonal vi~w of a wat~r cooling
~acket portion o~ on~ Pvrm o~ a radio ~re~uency sputt~rlng
target a~embly utilized in the radio rrequency deposition
ahamb~r o~ Fig. 97
F~ g. 12 i3 a ~ront elavational viow o~ kh~ sur~ac~ of
the target oX on~ ~orm of a radio ~reguency depo~ition target
assembly utilized ~p the radio ~xeguency depo~ition chamber
of Fig. 9:
L4~3
Fig. 12a ttenth sheet of drawings) is a diagram
showing variables in a mathematical model for
calculating the percentage concentration of two
substances, sputtered by the target of Fig. 12, at a
point on the surface of a substrate;
Fig. 13 is a sectional view of a portion of the
target of Fig. 12, taken along lines 13-13 of Fig. 12;
Fig. 14 i8 a rear elevational view of a direct
current sputter deposition chamber of the sy~tem of Fig.
1;
Fig. 15 is a vertical sectional view of the direct
current deposition chamber of Fig. 14, taken along
lines 15-15 of Fig. 14;
Fig. 16 is a vertical sectional view through the
load chamber of Fig. 1, taken along lines 16-16 of Fig.
l, and showing the load chamber loaded with a racX or
tray of substrate carriers;
Fig. 17 is a vertical sectional view of the chamber
of Fig. 16, taken along lines 17-17 of Fig. 16;
Fig. 18 is a cros~ sectional view o~ the chamber
of Fig. 17, taken along lines 18-18 of Fig. 17, and with
all but one of the substrate carriers removed;
Fig. 19 is a partially exploded isometric view of
one ~orm of substrate carrier utilized in the system o~
Flg. I to support substrate~ as they are processed by
the system;
~29~443
7a
Fig. l9a (twentieth sheet of drawings~ is an
isometric view of an altPrnate form of substrate carrier
utilized in the system of Fig. 1 to support substrates
as they are processed by the system;
Fig. l9b (twentieth sheet of drawings) is a
vertical sectional view of the substrate supporting
portion of the carrier of Fig. l9a, taken along lines
l9b-19b of Fig, l9a;
Fig. 20 i5 an exploded view of a carrier loader for
transferring substrate carriers from a tray to a
transporter which then transfers the carriers from the
load chamber to the deposition chambers of the system of
Fig. l;
Fig. 21 is an exploded view of a lift-lower bellows
mechanism of the loader of Fig. 20, which is utilized
for lifting substrate carriers from, and for lowering
substrate carriers to, the rack;
4~
Fig. 22 is an exploded view of a ~eed through utilized
to deliver operating ~luid to the li~t~lower bellowc mecha-
nism of Fig. 21;
Fig. 23 is a sida ~levatlonal view o~ one ~orm of a
transportQr, transportar track, and transporter drive mecha-
nism which tran~fers tha substrate carrier3, and thereby the
substrates, betwsen the chambers of the sy~tem of Fig. 1:
Fig. 24 i~ a vertical ~ectional vi~w of the trans-
porter, track, and transportQr drive mechanism taken along
lines 24-24 o~ Fig. 23;
Fig. 24a 1~ a side elevational vi.ew of a portion of the
transportor, track, and transport2r drive mechani~m, taken
along lines 24a-24a of Fig. 24, but with the transporter
shifted to a po~ition in which the tran3porter i8 ready to
cros2 ~rom the chamb~r in Fig~ 23 to a chamber to the right
of this chamber:
Fig. 25 is an ~xploded view o~ the transporter o~ Fig.
23;
Fig. 26 is an i~ometric vi~w o~ an end portion of a
plunger which li~t8 thQ ubstrate carrier~ from the tr~ns-
portar and rotate3 the sub~trat~ carri~rs during depo~ition,
the plunger being ~hown in Fig. 26 in po~ition for in~ertion
into a hub o~ a ~ub tr~te carrier:
Fig. 27 is an i~ometric ViQW 0~ an end portion of the
plunger o~ Fig. ~6, tha plunger being ~hown in engagement
with the hub Or the sub~trate carrier;
Fig. 28 i~ an ~xploded view o~ the plunger o~ Fig. 26
and o~ a plunger drive mschanism which operates tha plunger:
Fig. 29 is a schematic diagram o~ a water cooling sys-
tem utiliz~d in tha sy~tom oP Flg. l;
Pig. 30 is a schematia illu~tration o~ a portion o~ the
water coolinq ~y~tam ~or radlo ~r~quency sputtQring targets
o~ the type ~hown in ~lg~. 9-13;
Fig. 31 i~ a schematic lllu3tration o~ a portion o~ the
water cooling system ~or direct current cathode ~puttering
targets o~ the type shown in Fig~. 14 and 15:
Fig 32 i~ a ~he~atic diagram o~ a vacuum system uti-
lized in the ~ystem o~ Fig. l;
43
Fig. 33 is a block diagram of a s~eond embodiment of a
system for making thin film magnetic di~c~ and other products
in accordance with tha inventlon; and
Fig. 34 18 a block diagram o~ a third embodiment o~ a
system for making thin ~ilm magnatic discs and other products
in accordance with th~ present invention.
Modes for Carryinq out the Invention
General De~criptlo~ o~ First ~mbodiment
By way o~ a speei~le examplo, th~ ~ysta~ and method of
the present lnvention will be deseribed with re~pect to sevs-
ral pr~erred embodiment~ in an applieation in whieh plural
layers Or materials are deposited by vacuum depo~ition in a
low pre~ure gas environment upon ~ ~ub~trate tQ ~orm a thin
film magnetie reeording dise. How~ver, it i8 to be under-
stood that thQ ~y~tem and ~ethod i~ not li~ited to thi exem-
plary appllcation. That i~, the method and y~te~ i~ us2~ul
generally wh~n i8 i~ desired to vaeuu~ depo~it succe~sive
layers o~ material~ upon a sub~tra~e. By way o~ additional
ex~mple~, ~ueh applieations ineludQ the manufaeture of thin
film optieal reeording di~e~, lntegr ted eireuit ~anu~acture,
and the manu~aetur~ o~ othsr produet~.
In genaral, vaeuum depo~ition, within the meaning o~
thi~ app}i~ation, amploy~ a mechanls~ ~or e~ecting atoms of
coating mat~rial ~rom a ~ource Or target in a low pre sure
ga~ environmsnt. Th~ coating material ato~ are e;ected with
su~ici~nt energy to travel to the ~ur~ace o~ a substrate for
depo~ition th~r~on. Vacuum depo~ition thereby includes tech-
nique~ such ~ sputtering (including DC ~putterlng, RF sput-
tering, r~active ~puttering, et~.), evaporative deposition,
ion plating, and neutralizod ion bea~ coating. ~t does not
ordinarily lnclude chomical vapor dopo~ition, alectroplating,
or rapid ~olidi~iaation coating t~chniquo~. Ion plating i8 a
variation o~ both ~putt~rlng and avaporativo depo~ition which
involve~ th~ ioniz~tion o~ atom~ in th~ v por ~ollowed by at-
tra~tion o~ ~om~ ~brtion o~ th~ ionized atom~ to the sub-
strate with an olec~ric rield. Sinc~ ~put~ering is ~he most
~L~9~ 3
important vacuum deposltion m~thod used in the present inven-
tion, and i5 repre~entativ~ o~ the oth~r method~, the re-
mainder of this de~cription will concen rate on sputter depo-
sition. However, the principle~ di~cu~sed hereinafter are to
be conRidered a~ equally applicable to all vacuum deposition
technique~.
With ref~rence to Fig. 1, a first ~mbodiment o~ the
system 10 includes plural vacuum chamb~rs, which in this form
include~ 8iX such chambers 12 through 22. These cha~bers are
supported by a ~rame 24 ln a side-by-~ida relationship.
Ad~acent chambers are connected together by, and communicate
with one another through, a tran~r p,aa~ag2way auch as valve
containing hou~inge 26. Each o~ the~e valve hou~ings 26 in-
clude~ a valve 2a, OnQ being ahown in da~hed lin~s in Fig. 1.
When a valve 28 between two ad~acent cha~ber~ i~ open, the
adjacent chamber3 com~unicat~. with one another through the
valve hou~ing 26. This per~it~ tha tran~r o~ sub~trates
through th~ valve hou~ing and betw2en th~ chamber~. Con-
ver ely, when the Va1Y~ 28 i~ closed, th~ adjacsnt chambers
are i~olated and ~ealed by thQ valv~ fro~ on~ another. Valve
2 8 i8 operated b~twean its op~n and clo~ed po~ition~ by a
solenoid controlled pn~umatic cy}inder 30, on0 o~ which is
alco ~hown in da~hed lines $n Fig. 1.
Each o~ the chambQra 12 through 20 i~ provided with an
independently controllable separata simil~r high vacuum pu~p-
ing ~tack 34 ~or drawing a vacuu~ in the a~60cla~ed chamber.
An ind~pendently controllabl~ vacuum pumping ~tack 36 18 also
provld~d ~or ~stabli~hing a ~acuum in th~ cha~ber 220 There-
~ore, whenevar the valvo~ 28 a~30ciated with a particu~ar
chambsr are clo~ed, tho vacuum pumping ~tack associated with
that chamber i~ capable o~ ad~usting the pr~sure within such
chamber to a de~ired magnitude. Furthermore, this ad~ustment
may be made ind~pendently o~ the pre~urQ which exi3t8 in
other ohamber~ o~ khe systQm. 0~ cour30, a ~ingl~ pumping
stacX may alternately b~ u~ed ~or drawlng ~ vacuum in more
than on~ chamber.
In tho ~yste~ o~ Fig. 1, cha~bsr 12 compri~es a sub-
strate loa~ chamber m~an~ into which ~ubstrate~ are loaded
43
11
for processing by the ~ystem. Al~o, chamber 22 comprises a
sub~trate unload cha~ber mean~ from which processed sub-
strates are removed from the ~y~tem. In addtion, the cham-
bers 14 through 20 comprise proce ~ing or deposition chamber
means within which layers of mat~rial are deposited onto sub-
strate~ while po~ition~d therein. More specific~lly, each of
the chambers 14 through 20 comprises a ~puttering chamber
within which material from sputtarin¢J targets is sputtered
onto the substrates. Further morQ, :in the speci~ic illu5-
trated embodiment, becausa of the type of material being
sputtered therein, chambers 14, 18 and 20 comprisQ DC
sputtering chambers whll~ chamber 16 compri~ea an RF
aputtering chamber. A pair o~ DC sputtexing cathode
assemblie~ 40 are ~ounted by a circular support pl,~te 38 to
the front o~ each o~ the chambera 14, 18 and 20. In
addition, an RF sputt~ring cathod~ a~sambly 42 ia mounted by
a circular aupport plate 39 to th~ front o~ tha chamber 16.
Similar a~semblies are mountQd to the rsar of thes~ chambers.
These as~e~bliea may bh re~dily r~placed by ~imply removing
the support plata~ 38, 39 and replacing thQ aa~embliea with
other asse~blie~ mounted to similar plates 38, 39.
During proce~aing, aub~trates pas~ along a proces3ing
pathway through the chamb~r~ an~ are positioned between the
front and rear aputtering a~ssmbliQ~ in the depo~ition cham-
bers 14-20. Whan in ~uch chambers, both ~ides of th0 ub-
~trate~ are si~ultaneou~ly depo~ited. That i~, the front
cathode sputtering a6~e~blie~ depo~it a layer on a ~ront sur-
face of each ~ubetrate and the rear cathode sputtering as~em-
blies depo~it a layer on a rear surface of each substrate.
A~ explained in greater det~il below, in general, cham-
bers 14 through 22 are ~vacuated with the valve 28 isolating
chamber 12 ~rom ahamber 14. Substrates to be proce~ed are
loaded in chamber 12 an~ then thi~ cha~ber i8 evacuated.
Thereafter, th~ sub~trates are transporte~ ~orm chamber to
chamber ~or proce6sing. B~cau~ the chambers are isolatable
from one another by the valves 28, tha desired operating
parameters may be ~tablished within each chamber for the de-
position to be per~ormed therQin. At the ~ame time, other
~L~9~3
12
parameter~ may be establi~hed in other chambers to optimize
the deposition being performed in such other chambers. Fur-
thermore, because of the isolation capabilities of the
system, two ad~acent evacuated chambers may be i~olated from
the other chamber~. In this ca~e, the ~ubstrates may be
transported through an o~en valve 28 betwsen these chambers
without losing the vacuum in either of the two chambers.
The isolation capabilitie~ of the cha~bers facilitates
maintenance of the sy~tem. During the rapair or replacement
of cathode assemblie~ in one or more cha~ber~, such chamber
or chambers may be isolated from the other cha~bers by the
valve 28 and then exposed to the ambient environment durlng
thQ maintenanca proceduras. A3 a re~u:lt, thQ cathodQ assem-
blies in ths othQr cha~bers are isolat~d ~rom the a~bient en-
vironment and are ther~ore not expos~d to contaminants such
as water vapor and oxygen. In addltion, bacaus~ o~ th~ iso-
lation, a high vacuum can be mainainQd in all o~ the cha~bers
except tho e being repaired. Following repair, 1es ~yst~m
down tima is re~uired becau~e one does not hav~ to re
establish a high vacu~m in all cha~ber~ o~ the sy~tem, but
only in those chambers af~acted by t~e maintenance.
After a batch of sub~trate~ have been proces~ed, they
are removed fro~ the unload chamber 22. During such removal,
the unload chamber i~ isola.t~d from the ad~acent processing
chamber 20 ~o that proc~ing may continue during the un-
loading operation.
The per~or~anc~ of the depo~ition proces~ is monltored
and controll~d utilizing a control subsystem including a pro-
grammed digital computer 46 in con~unction with one or more
terminals 48. Line 50 schsmatically repr0s~nt~ data lines
along which signal~ are transmitted ~rom sy~tem sensors and
other system compon~nt~ to the control 3ubsystem~ In addi-
tion, llne 52 ~chematlcally rapr~s~nt3 control lines along
which control signal~ are tran~mittad to the sy~tem for con-
trolling the operation o~ valves ~nd other components o~ the
system duxing ~yst2m op~ration. The programming o~ computer
46 i9 explained be~bw.
~29~3
13
Load. Unload, and De~o~ition Chamber~
With rQferenc2 to Fig~. 1 through 3, the hou ing ~or
load chamber 12 i~ generally of a rectangular box-lik~ con-
struction having ~irst and ~coned vertical side walls 56,
58, horizontal top and bottom wall~ 60, 62, and a rear wall
64. In addition, a perimeter flange 66 i~ attached to the
front edge~ o~ the top, bottom and side wall and surrounds
an opening leadlng to the interior of the chamber. A door 68
i~ mounted at one ~ide by hinges 70 to the flange 66. The
door includes a perimet~r ~lange 72 which abuts the ~lange 66
wh~n the door i3 closed. A seal 67 ~Fig~. 16, 18) is pro-
vided b~tw~n th~ ~langes 66 and 72 to tightly ~eal the door
68 again~t ths chamber flange 66 when thQ door i~ closed.
pair of latchQs 74 are pivotally mounted to th~ free edge of
the door. When plvoted to a latch~d pos~tion, as ~hown in
Fig. 2, latch roll~r~ 76 o~ the~ latche~ abut the rear sur-
face of the ~langa 66 and aecuxe the door clo~ed. The lower
edge of the door i9 suided to it~ closed position by a roller
78 supported by a bracket 30 a~ to project ~orwardly form the
lower edge o~ the p~rimeter flange 65. Therefore, the door
is guided to its clssed position and tightly held in place
when latched.
A~ bo~t shown in Fig. 3, the wall 58 is provided with a
v~rtically elongated ~ub~trat~ pasa through opening 82.
opening 82 co~municate~ with the interior o~ the valve
housing 26 when the ~yetem iB asssmbled as ehown in Fig. 1.
A similar pa99 through opaning i~ provided through the ad;a-
cent ~ide wall o~ th0 ad~oining depo~ition cha~b~:r, a~ ex-
plained below. Th~re~ore, when the valve 28 i~ open, the two
chamber~ communicate with one another through the~e pas~
throuyh opening~ and the valve hou~ing. Aa a re~ult, when
the ~alva 28 i3 open, the trans~er o~ ~ubatrates between
ad~acent chamberY i~ par~itt~d.
The bottom wall 62 o~ chamber 12 is providod with an
opening 83 ~Fig. 3) through which a vacuum i~ e~tablished by
the pumping ~tacX ~ (Fig. 1). A cylindrical pumping stack
attachment ~lange 84 ~urround~ opaning 83. Flange 84 pro-
, ,
. .
, .
14
jects downwardly ~rom the bottom wall 62 and, as shownin Fig. 1, the pumping stack 34 is attached to flange
84.
Sealed view ports 86 are provided through the top
wall 60 and side wall 56 to enable an operator of the
system to visually inspect the interior of chamber 12.
Ports, one being indicated at 88, through the rear wall
64 o~ chamber 12, are provided for passage o~ system
components such as transporter drive mechanisms and
loader drive mechanisms into the chamber. In addition,
other openings, not shown, are provided for pressure
gauges, air supplies and the like.
When the chamber 12 is mounted to the frame 24, a
pair of support bars 90, connected to the undersicle of
chamber bottom wall 62, rest on a horizontal plate
portion of the frame 24. This provides a stable support
for the chamber. The frame itsel~ is leveled so that
the chambers are aligned vertically and the~openings 82
are in a straight line.
The unload chamber 22 is a mirror image of the
chamber 12 and for this raason will not be described in
detail .
With reference to Figs. 1 and 4, all the deposition
chamber housings are of similar construction. For this
reason, the deposition chamber housing will be
described with re~erence to the housing ~or chamber 14
shown in Fig. 4. Further~ore, the deposition chambers
are similar to the load and unload chambers 12, 22.
Therefore, components o~ chamber 14 which correspond to
similar components o~ the unload and load chambers are
correspondingly numbered.
,~ A 7
., ' ~
~;~9~4~3
14a
Deposition chamber 14 differs from the load chamber
12 in that it lacks a hinged door and a perimeter flange
66. Instead, a front plate 92 i5 provided at the front
of the deposition chamber. The front and rear walls
64, 92 of chamber 14 are provided with circular openings
94, 96. The sputtering assembly support plates 3~ and
39 are secured to walls 64, 92 to close these openings
and mount the sputtering assemblies 40, 42 in position
for deposition within the chambers. Also, because the
chambers 14 throuqh 20 are each intermediate to chambers
adjacent to each side wall thereof, openings 82 through
which the substrates pass are provided throuyh each
of the side walls of the~e chamber~. Cen-~equently,
substrates may be passed from one chamber to the next during
operation o~ the system 10. The top wall 60 of the
deposition chamber~ i~ detachably mounted to a flange 61
provided at the upp~r edges of the chamber front, rear and
side walls. A ~eal i8 po~itioned between these co~ponents
60, 61. Access to the intQrior o~ the deposition chambers is
thereby provided fro~ above.
Each of the cha~ber~ 12 through 22 are o~ rigid durable
constru¢tion and are form~d o~ a 3trong mat~rial ~uch as, for
example, stainles~ steel or aluminum.
Isolatio~ Valve9
The valve as~embli~ for salectively i801ating the re
spective chambar~ 12 through 22 ~ro~ each other are illus-
trated in Fig~. 5 through 8. A3 pr~viou~ly mentioned, each
valv~ a~sembly include~ a valve housing ~6 within whieh a
valve 28 i~ poaitionad and operated by a pneumakic cylinder
30 to selectiv~ly open and close th~ val~ hou~ing. When the
valve i~ open, a pathway 1~ provided through tha valve
housing and batwe~n ad~ac~nt chamber~0 Con~er~ely, when the
valve i~ closed, th~ ad~acent chambers are isolated, that is
sealed, fro~ ono another.
~ ore ~pecifically, tho valv~ housing 26 includes a
first hollow box ~ction 100 which de~in~s an internal first
valve passag~way 102 and a ~econd hollow box section 104
which defines an internal second valve pas~ageway 106. The
valve hou~ing al30 include~ a hollow bonnet 108 intermediat~
the sections 100 and 104. The valv~ passageways 102 and lOÇ
communicate with on~ another through the valve bonn2t ~xcept
when a valve 28 compri~ing a gate valve 110 is ~hi:Eted to a
closed po~ition, a~ ~hown in Flg. 7. When cloae~, the valve
110 seal~ rir3t valve pas~ageway 102 ~rom the ~econd valve
pa~agaway 106.
~ he ~irs~ and second valvo pa~ag~way~ 102 and lOfi are
o~ the sams cross 3ectional size and shap~ as thQ chamber
~ide wall pa53 ~hr~gh openings 82. For that matter, in the
illustrated embodiment, t~e opening~ 82 are Rized to permit
9LX9~443
the passage of components which are three inches (7.62
centimeters (c~)) wide and twenty-two inches (55.88 cm) high.
The valv~ section 100 is provided with an attachment flange
112 which is ~Qcured to a wall 58 of one of the chambers with
the chamber pass through op~ning 82 aligned with ~he first
valve pa-q~ageway 102. ~180, the valvs section 104 i~ pro-
vided with an attachment flange 114. Flange 114 is secured
to a wall 56 of an ad~acent chamb2r with the chamber pass
through opening 82 aligned with tha valvs pa~sageway 106.
Seal~ 113 and 115 seal the connection betwesn the respective
flanges 112, 114 and wall8 58, 56.
Therefor~, with th~ valve 110 ~oved to its op~n posi-
t$on 3hown in da~hed line~ in FigO 7, 3ubstrate~ may ba
transferred through the valve housing 26 between ad~acent
chambers such as in the direction indicated by the arrows
118. Convar~ely, whon the valve i~ in ths clo~ed pocition
shown in Fig. 7, th0 ad~acent cha~ber~ are 6ealed from one
another by the valve. When ~ealed, ~ubstrate transfer
b~tween the chambers i~ blocked and dif~erent ga~ pressure
environment~ ~ay be maintained in the chambers. The valve
110 provides s~ective ~ealing betwe~n the c~ambers. The
illu~tratsd valve ha~ a maximu~ leak rate of 1 ~ 10-9
atmosph~res p~r cubic centi~ter per ~econd when sealed
against a one atmo~ph~re di~erential in either direction
across th valve.
The bonnet section 108 i~ o~ rectangular box-like con-
struction with parallel spaced apart ver~ical ~ide wa~ls 122,
124 and an end wall 126. The other end of the bonnet section
is clo~ed by a cover 133 mounted to a ~langs 132. ~ top wall
128 and bottom wall 130 co~plete the bonnet. One ~ur~aca o~
the valve 110 engage~ the interior ~urracs o~ wall 124 as the
valve is moved b~tween open and clo~ed positions. A valve
~eal 134 carried by valvo 110 i8 po~ltioned between the valve
and wall 124. Seal 134 surrounds the valve pa~sageway 102
for ~ealing purposes when the valv~ i~ clo~ed. Rollers, ~or
exampl~, 138 in Figs. 7 and 8, bQar against interior surfaces
o~ the bonnet wal~ 122 and urga the valvs 110 against the
wall 124. More ~p~ci~ically, the roller~ 138 are pivoted to
~:9~L~413
valve 110 by links 139 (Fig. 7). As th~ valve approaches a
closed position, the roller~ 138 which lead the motion abut
the end wall 126. Continued motion of the valve 110 causes
the link3 139 coupled to such roller~ to pivot so that rol-
lers 138 bear again~t wall 122 and urge valve 110 against
wall 124.
A~ previou~ly mentioned, a cylimder 30 is l~tilized to
shift the valve between its open and closed po~itions.
Cylinder 30 is pneu~atically operated and, a~ shown in Fig.
6, ha~ a piston 140 positionad within a cylinder housing 142.
A pi~ton rod 144 extends ~rom pi~ton 140, thro~lgh a seal, and
into ths bonnet 103 wherein the end o~ the pi~ton rod en~age~
the valve 110. An air~low valve 146, controlled by a
301enoid 152, directs air either through a conduit 148 or a
conduit 150. With air directQd through conduit 148, the
piston 140 is shlfted to the right a~ ~hown in Fig. 6 and the
valve 110 is open. Conver~ely, with air directed through
conduit 150, the piston 140 i~ shi~ted to the le~t in Fig. 6
amd the valvQ 110 i~ clo~d. Solenoid 152 control the
position of the valve 110 in re~ponsQ to control signals
generated by th~ computer 46 (Fig. 1). Conductor~ 154
deliver power to the sol~noid.
First and ~econd valve po~ition sen~ing limit switche~
156, 158 ar~ provided ~or dekecting the respective open and
closed position~ o~ the valve and tran~itting a signal indi-
cating the valve po~ition to the computex. With r~erence to
Fig. 6, when the valve i8 in an open po~ition as shown in
this ~igure, a spring biased ~tem 160 o~ ~en~or 156 is posi-
tioned in an annular groove 162 ~ormed in ~he pis~on rod 144.
When th~ ~tem 160 is in this position, a valve open indica-
ting Aignal i9 transmitted by th~ eensor 156 to the computer.
At the same time, the etem 164 o~ tha sen~or 158 is held in a
retracted po~ltion by the pi~ton rod 144. In contrast, when
the valve iB in a closed po~ition, the ~te~ 164 i~ positloned
in an annular groove 168 ~or~ed in the piston rod. When ste~
164 i~ in groove 168, a valv~ clo~ed indicating ~ignal is
~ent from the ~ens~F 15~ to ~he computer. At the same time,
the piston rod 1~4 holde tha stem 150 in a retracted posi-
~9i44~
18
tion. In this manner, the position of each valve ismonitor~d and controlled by the computer.
Thus, valvs housings 26 provide one form of a
transfer passageway through which chambers of the system
10 may communicate with one another. Furthermore, the
illustrated valv~ structure provides one form of
effective means for selectively isolating the
respective chambers from one another.
Deposition Processinq Chambers
The processing chambers 14, 16, 18 and 20 in which
sputtering takes place are shown in various ones of
Figs. 9 through 15. During substrate processing, as
explained below, substrates are first transported from
the load chamber 12 to the deposition chamber 14.
Sputtering is performed in chamber 14 to simultaneously
deposit an underlayer, e.g., chrome, on each side of
substrates positioned in chamber 14. Thereafter, the
substrates are transported to chamber 16 wherein a
second layer is simultaneou~ly sputtered onto each side
of the substrate. The second layer may comprise a
magnetic material, such as a cobalt platinum layer.
From chamber 16, the substrates are transported to
chamber 18 wherein a third layer is sputtered
simultaneously onto both sides of the substrates. This
third layer may be of chrome and comprises an oxidation
barrier which minimiæes diffusion of potentially
corrosive oxygen through the third layer to the magnetic
layer. The partially processed substrates are then
transferred to processing chamber 20. In chamber 20, a
wear layer, such as of carbon, is simultaneously
sputtered onto both ~ides of the substrates to complete
"
~.
:-
~291a~3
18a
the processing. From chamber 20, the substrates are
transferred to the unload chamber 22 for subsequent
removal from the system.
Radio Frequency S~utterin~ Chamber
In the illustrated embodiment, chamber 16 comprises
a radio frequency deposition chamber and is described
with reference to Figs. g through 12. First and second
vertically oriented radio frequency cathode assemblies
42 are supported within the chamber 16 along the front
and rear walls of the chamber. Inasmuch as these
assemblies are simi-
43
19
lar, only the front a~sembly will be described in detail. Aspreviously mentioned, a~sembly 42 is mounted to support plate
39 which ls in turn mounted to the front wall g2 of the depo-
sition chamber. An optional central cylindrical view port
may be used to provid~ visual acce~s to the i~terior of the
chamber through plate 39. An annular target inaulator 172 is
secured to the ~upport plate 39. Th~ in~ulator upport~ a
water cooling jacket to which a ~puttering target 174 i
mounted. The sputtering surfac~ 176 of target 174 is paral-
lel to the front wall o~ thQ cha~ber and al~o to the front
~urface of substrat~s positioned in ths deposition chamber.
The watar cooling ~acket include~ a ~acket rrOnt 17a to
which a ~acket back plat~ 180 is ~ecured. The ~acket front
178 and tho ~ac~st back plata 180 are ~ormed o~ an
electrlcally conductivs mat~rial ~uch as copp0r. A~ ~hown in
Fig. 11, tha ~ack~t front 178 i~ ~nnular and include~ an
outer cixcular rib or wall portion 1~2 and an inne.r annular
hub 184. The ~acket back plato 180 1~ an~ular and when
mounted to jacket front 1781 as ~hown in Fig. 10, has it8
outer ~urface ~lush with th~ out~r ~ur~aces of wall 182 and
hub 184. Channel~ 190 aro ~orm~d in the ~urface of ~acket
front 17~. The~ channel~ ar~ ~eparated by chann~l de~ining
walls which abut tha innQr sur~ace o~ back plate 180 to closa
the channel~ wh~n th~ ~ackot back plate and ~ack~t front are
as~embled. ~hus, togQth~r with the back plate 180, these
chann~l~ provido a circuitou~ cooling water ~l~w path ~hrough
the cocling ~ack~t. Thu~, cooling wat~r enter~ an inlet 192
and flow~ in the channel~ in the direction o~ arrow~ 194 to
an outlet 196. Thie cooling water maintains the operating
temperature~ o~ the ~putterin~ targ~t~ 174 at de~ir~d levels.
Water ~upply and return lines 198, 200 (Fig. 9) are re-
~pectively conn~cted to inlet 192 and outlet 194 to circulate
cooling water to and ~rom the coollng ~ack~. The conduits
198, ~00 may be electrlcally conductlvo and used to supply RF
power to tha target etructur~ a~ wall a~ the coolant fluid.
Typlcally, however, RF power i~ supplied along water supply
line 198 wh$1e wa~er return lina 200 15 o~ an insulating
mat~rial, ~uch as pla~tic. A wat2r line shield 202 is
mounted to the support plate 39 and protects the water supply
and return lines at the location where they enter chambar 16.
Seals, some being numbered at 204, seal the chamber 16 so
that a high vacuum may be drawn by the vacu~m pumping stack
34.
In the Fig. 1 sy~tem, chamber 16 is th~ rhamber within
which deposition o~ the working magnatic layer of a thin film
magnetic disc is accompli~hed. In the illustrated embodi-
ment, this magnetic layer i~ formed by sputtering a target
composed o~ cobalt and platinum.
To understand the sputtering process, basic in~ormation
concerning the materials tran~port ~y~kem ~escribed in detail
below i8 needed. In general, sub~trates 260 to be processed
are supported by a carrier 220 (Fig. 19) with the carrier and
substrates b~ing tran~ported ~rom chamber to chamber by ro-
bot~ or transporters 222 (Fig. 10). The transporter 222 i~
supported on a trac~ 224 and driven by a tranRporter drive
mechanism 226. During ~puttering, tho carriers 220 are sup-
ported in a vertical plan~ with th~ ~ubstrates 260 centered
betwsen the two targ~t assembli~ 42 o~ the dQposition cham-
ber. More peci~ically, the transporter 222 positions the
carrier in the c~ntar of the d~position chamber 16. When so
positioned, a plunger 228 i~ operat~d by a plunger driv~ me-
chanism 230 to ~lrst shi~t th~ plung~r axially to insert a
CarriQr gripping tip portion 232 o~ the plunger into a hub
278 (Fig. 19) o~ th~ carrier. The plunger tip then grip~ the
carrier and li~t3 it upwardly from th~ tran~porter 222. The
tran~porter 222 is then driven to a parked position within
tha chamber, but out o~ the way og the cathode as~emblies 42
and tha depo~ition proces~. Additionally, the plungar 228 i9
rotated to therQby rotate the carrier. The di~cs 2~0 are
supported (i.e., by ~heave~ 288 (Fig. 19) or in groove~ 283
(Fig. l9a)) such that rotation o~ the plung~r cause~ the
discs to move in a pl~natary manner past th~ ~puttering tar-
get~ 174. An opening 238 (Fig. 12) is provided thrcugh the
target 174 to permit pas~ag~ of the plunger 228 through the
target and into th~depo~ition chamber.
~ -~
., ~
21
Referring again to th~ target 174 used in
depositing the magnetic working layer, the target may be
a homogeneous cast mixture of platinum and cobalt with
the percentage of the platinum being controlled to
establish the magnetic properties of the resulting
sputtered layer. As one example, a ninety~six percent
cobalt to four percent platinum target is suitable.
However, because of the expense and difficulties of
casting a homogeneous target, in the illustrated
embodiment, the target 174 is formed by mounting a
platinum ring 206 concentrically to the surface of an
annular cobalt plate 208. A concentric cobalt ring 210,
with an outside diameter which is less than the diameter
of the platinum ring, holds the platinum in place. The
ring 210 has an annular recess 212 for receiving the
inner margin of the platinum ring. Threaded fasteners
214, recessed into cobalt ring 210, secure the cobalt
ring 210 to the plate 208 and thereby clamp the platinum
ring 206 in place. Cobalt plugs 216 overlie the
2n fasteners 214. Plugs 216 are press fit into the
fastener receiving recesses of ring 210. Thus, the
sputtering surface 176 of the target 174 is entirely of
cobalt, except for the exposed portion of the platinum
ring.
The area or width of the platinum ring which is
exposed determines the platinum to cobalt ratio which is
sputtered onto a substrate. Moreover, over a limited
range (i.e., from approximately a zero to a twenty
percent platinum concentration), the higher the
platinum concentration, the hiyher the coercivity of the
resulting magnatic layer. Therefore, by adjusting the
magnitude of the exposed area of the platinum ring, a
degree of control of the coercivity of the resulting
disc is achieved.
~,'9' ' i
'i
9~D~43
21a
In general, to obtain a film of a desired platinum
concentration percentage, the ratio of the exposed area
of the platinum ring to the total target area should
equal this desired percentage. Thus, to form a
magnetic layer having a platinum concentration of three
percent, the exposed area of the platinum ring should
constitute about three percent of the total target
sputtering surface area, the remaining ninety-seven
percent being cobalt. The area of the platinum
~29~l~43
22
ring 206 which i~ e~po~ed, and thereby tha platinum concen-
tration, is readily controlled by controlling the outside
diameter of the cobalt cover ring 210. The diameter o~ cover
ring 210 may be varied a~ de~irad to Qxpo~e the desired area
of the platinu~ ring. Therefore, the percentage content of
platinum in the sputt~ring magnetic layer i3 readily
adjustable, controllable and predetermined as desirad.
As a more specific example, as~ume plural ninety-five
millimeter discs are supported (a~ shown in Fig. 17) on
sheaves 288 mounted on a circular carrier 220 and spaced at a
radius o~ 7.28 inches (18.49 c~) from the center of the car-
rier to the c~nter o~ the 3hsæve~. In thi~ example, also as-
sume that in deposition chamber 16 a two inch (5.08
cm) horizontal spacing exist between the ~ront and rear
~puttering ~urfaces 176 ~nd the ad~acent surface~ of
substrates 260. In addition, a~sume thQ target 174 hac a
cobalt plate 208 which i8 about 0.25 inche~ (0.64 cm) thick
and i~ about twen~y-~our inche l60.96 cm) in ou~side
diametar. Al o, as~ume the platinum ring 206 iR about 0.35
inches (0.76 cm) thick, 12.6 inche~ (32 cm) in outside
diameter and 11.6 inch~a (29.46 c~) in inside diameter. In
addition, a~sume th~ cobalt covering 210 ha~ an in~ide
diameter of about 10.5 inche~ (26.67 cm) and an outside
diameter o~ 12.28 inche~ (31.19 c~). Also, a~sume the
thicknes~ o~ tha cover ring 210, where it contacts the cobalt
plate 208, is about O.Q96 inche~ (1.24 cm~. Thus, the inner
diamet~r of the expo~ed portion o~ the platinum ring is 12.28
inche~ (31.19 cm). When planetary motion i~ impart~d to the
~ubstrates as explained in connection with a description of
carrier 220 balow, and 5putt9xing i9 per~ormed as explained
below, the re~ulting magnetic layer has approximatoly a three
to four percent platinu~ concentration. Al~o, when this
speci~ic platinum ring i~ ~ubstantially totally exposed, the
resulting platinu~ concentration is about t~n percent,
although this varios with di~erant substrat~ ~izes. Also, a
zero p~rcent platinum concentration results when th~ platinum
ring is totally 2Pvered by cobalt. Other results are
obtained for other di3c ~ize~ and geome~rie~.
. ,~
....... .
43
23
Each of the cathod~ ~puttering a~semblie~ ~2 is powered
by a commercially available 30urc~, such as a three kilowatt
radio ~requency diode source produced by Plasma Products,
Inc. and designated model number ~FS-3000D. In addition,
commercially available radio frequency automatic matching
networks 674 (Fig. 30), such as nstwork model number AMN-300E
available fro~ Pla~a-Therm, Inc., are employed in a conven-
tional manner.
During sputtering in chamber 16, ~ub~trates 260 are
placed in the previously evacuated cha~ber. The chamber is
then pressuriæed with approxlmataly ~eYen microns of argon
sputtering ga~. The ~puttering ga~ iB ignitad in a conven-
tional manner to provid~ a pla~ma ln thQ chamber. Also,
power i delivered to the targ~t 174 to cause sputtering.
The aarrier and sub~trat~ are grounded through the plunger
228. As the plunger rotate~, planetary motion i8 i~parted to
the sub~rat~s and the targ2ts depo~i~ co~alt and pl.atinum on
the ~ubstrate~ supported by the carrier. With 1800 watt~ of
power deliYered to each targ~t 174, in approxi~ately two and
one half minutQs, a ~our hundred ang~trom magn2tic layer is
produced. Although tha thicknas~ may be varied and still re-
sult in a ~ati~actory ~agn~tic thin ~ilm r~cording ~i5C, a
four hundred angstrom layer ic highly sati~factory.
~ 130, wh~n supported ~or plane~ary motion, the 8Ub-
tra~es move relative to th~ ~puttQring surfacQ 176 duringsputtering. ~oreover, any givQn point on th~ substrate is
continuou~ly shl~t6d to points on the target ~putter~ng sur-
fac~ 176 which ar~ inter~ected or mappQd by a horizontal line
pro~ecting from the given point to the ~puttering surface.
HorQ sp2cl~ically, any given point on the ~ubstrate maps in-
wardly and outwardly ~piraling path~ on the sputtering sur-
~ace 176. Thu~, the given point and other point~ on the sub-
~trate sur~ac~ are not con~tantly ~putt~red by the same re-
gion or rQgions of the sputtering surfac~ 176 during deposi-
tion. AB a re~ult, any non-uniformities in ~puttering from
particular region~ o~ tha ~arget 174 t~nd to be averaged so
that a layer of cop~istent thickne~ i3 sputter2d onto the
sub3trates. That i8, substrate ~otion relative to the target
1~9~3
24
is such that non-uniformities in sputtering from particular
regions of the target are uni~ormly integrated or averaged
over the ~puttered surface of the substrate.
~ urthermore, the deposition rate is uniform to within
~ive percent at the subatrats plan6~ at locations from
approximately three and onehalf incheæ ~. 89 cm) to ten
inches (25.4 cm) from th~ center o~ the plunger 228. Thus,
the system i~ u~able in producing various sized thin ~ilm
magnstic discs by supportlng such disc~ at location~ on the
carrier where uni~orm d2po ition ocauxs. common disc sizes
proces~ed by the system include ninety~lvls millimeter (three
and one-half inch) diam~tQr diacs, one hundred thirty
millim~ter (~ and one-~ourth inch) dia~atsr disc~, and two
hundred ten millimeter (eight inch) diamater diac~. ~agnetic
coercivity is affect~d by the thickn~s~ of th~ sputtered
magnetic chromium layer. Th~re~ore, by controlling these
thickness2~ from disc to di~c, the re~ulting disc~ ha~e a
con~ist~nt coercivity. For exa~ple, the coercivity ~ay be
controlled to wi~hin ~w~nty oersted~ ~ro~ di~c ~o disc.
Furthermore, the u e oP a target 174 with a platinum
ring 206, enables th~ establish~ent of a radial coercivlty
gradient in th~ rasultant di~c. When di~cs are u~d in typi-
cal magnetic recording disc drive application~, the disc ia
annular, is rotated, and a r~ad-write head i8 po~itioned to
fly over and read or writQ on concentric ~rack~ on the disc.
The sp~ed of travel o~ th~ head, rslative to the disc, is
greater and th~ head ~lies higher over the disc when the head
is reading or writing onto outsr tr~cks at outer diameters of
the disc in comparison to inner tracks at inner diameters.
Also, in magnetic recording discs, the recordiny density is
much high~r on tracks approachlng the inner diamet~r of the
di~c in comparison to the density on tracks toward the outer
diam~ter.
A~uming a di~c haa a magnotic layer ~ith a constant
radial co~rcivity, writing in track~ near the outar diam~ter
o~ the disc i~ lmpo~ible or unreliable unle~ the writing
current i9 incre~ed a~ ~uch outsr diameter tracks.
Increa3ed wrlting current i3 re~uired becaus~ the head flies
~29~4~3
higher above the disc surface as the head moves
outwardly from inner to outer tracks of the disc. In
order to write with a constant current, which in many
applications is highly desirable, the radial coercivity
of the magnetic layer must be adjusted so as to decrease
as the flying height of the head increases. In other
words, the coercivity of the disc should decrease with
increasing radial distance from the center of the disc.
Therefore, discs with a radial coercivity gradient
are desirable, with the radial coercivity decreasing in
a radial outward direction from inner to outer dia~eters
on the disc. In the present system such a gradient
established by progressively decreasing the
concentration of the platinum in the cobalt of the
magnetic layer from inner to outer diameters of the
disc. As the platinum concentration decreases, the
coercivity decreases. The gradient is also enhanced by
varying the thickness of the first sputtered chromium
under layer as explained below.
In the illustrated embodiment, by sizing the
platinum ring 206 such that the center of the exposed
portion of the ring is nearly centered on the center of
the sheaves 288 (Fig. 19) of the carrier 220 (Fig. 1~),
a radial coercivity gradient is produced which is about
fifty oersteds from inner to outer diameters of the
discs. As the platinum ring size is changed to shift
the center of the ring away from the center of the
sheaves 288, the radial coercivity gradient approaches
zero and then reverses.
The percentage platinum concentration at locations
on a substrate, and thereby the radial coercivity
gradient, which results ~rom a particular platinum ,
cobalt target configuration may be experimentally
measured. In addition, the percentage platinum
~,`' .
's~
~L2~ 43
25a
concentration resulting from sputtering with a target
174 comprises of a platinum ring 206 concentrically
mounted on an annular or circular cobalt plate 208 may
be predicted with some accuracy by the following
mathematical model, which is descri~ed with reference to
Fig. 12a.
~,,
dt3
26
In this model, the following daPinitions are u~ed:
Target Plane: The plane 176 de~ined by the surface of
the cobalt plat~ 208.
Substrate Plane: The plane which i~ parallel to the
target plane and which contains the surfaces of the disc sub-
strate~ 260 being sputtered from the karget as the substrates
rotate on the substrate carrier 220.
An equation (Equation A) de~cribing sputtering ~rom a
single infinitely narrow ring of a homog~neou~ target to any
arbitrary point ln the eubstrate plane i~ given in a prior
art publication, entitled Handbook oX Thin Film Technolo~y,
edited by Mal~sQl and Glang, published 1970, at page 1-58, as
~ollows:
= Cs ~1 + ~ e /h)2 ~ (5/h~23 ds (A)
h2~tl - (e /h)2 + ~h)2]2 + 4 (e/h)2]3/~
Where:
N - th~ deposition rate (atoms per unit ti~e) ~t a point
Pl at a radius e in the ~ub~trate plan~.
C = a con~tant proportional to the 3puttQr rate or yield
of the target material.
s = a variable repr~nting the radius of the target ring,
fro~ th~ origin Cl of the target, in the target
planQ.
e = a variable repre~enting the radiu~ from the origin C2
of the sub~trate plan~ to the point Pl. The origin
C2 of the aub~trate plane being on a line nor~al to
the target plane and pa9~ing through the origin Cl o~
the targ~t plane.
h ~ a v?riable repre~entlng the distance separating the
targe~ plan~ and the ~ub~trate plan~ ~i.e., the
dl~tanca ~rom Cl to C2).
For a ring 2~6 o~ platinum QxposQd on a cobalt plate
208, the ring 206 havlng an in~ide radiu~ o~ S1 and an out-
~ide radiu~ of S2 ( each radius being measured ~rom center .
Cl), the equation (Equation B) can be integrat~d as follows:
s
N (e) Cpt / 5~1 + ( /h)2 -~ ~s/h)2] dg
h2 Sl [[1 - (e/h)2 + (SIh2]2 ~, 4(e~h~2~3/2
Simllarly, ror a target sur~ace 176 with an out~ide ra-
diu~ oî S3 extending to an in~ide radills o~ SOI and which is
entirely o~ cobalt except ~or the above de~crib~d platinum
ring 206, the ~ollowing equation ~guation C) can b~ written:
S
Co( Q ) D CCo ~ [ ~ /h)2 + (s/h ] d~ _ 2 3/2
h J [[1 - (e /h)2 ~ (~/h) ] + 4 (e/h) ]
J ~3 El + (e/h)2 + ~s/h)2L ds ._ c
[[1 - (e/h)2 + (s/h)2]~ + 4 (e/h)2l3/2 ( )
;
In tll~ above equation~, th~ criptY Pt and Co refer
re~pectively to pl~tlnu~ and cob~ltO ~or a point Plon a disc
260 located OTl a carri0r 220:
e. eO+~
where
e o ~ the radius ~rom tho center C3 o~ the disc s~strate
260 to th~ center C2 ~ the ~ trate plane; and
r,~", coordin~es oi~ a point ~1 on the ~ trate disc 260
r~l~tive to its gaoDIetric cent~r C3.
Not~: a8 an approxi~nation, the cent3r C3 o~ tha sub-
strate iY a~awll~d to b~ at ths ~anter Or the ~upporting
sheave 288. Thi~ i~ valid ~hen th~ 3h~zw~ diæmater i9 ~imi-
lar to ~h~ dlam~t~r og th~ c~ntQr hol~ in th~ ~i3c 260.
Equation~ (B) and ~C) becom~:
N~t ( r ,~) ~ Npt ( O ~ r co~)
l~Co ~r,~) ~ Nco ( O + r cooe)
where Npt ( eO ~ r co~) and Nco ( ~ + r ao~e) imply the
sa~o function~l depQndenco de~crl~ed ln eguations (~) and (C)
with e O ~ r co~ ~ubstitlatfid ~or e .
43
2~
The motion ef a point Pl on ths di~c ~ub~trate 260 as
it undergoe~ planetary motion during rotation of the sub-
strat~ carrler 220 i~ accountQd for by integrating over the
angle ~: 2
Npttr) ~ 1 ¦ Pt ( eO + r c~s~
NC (r) - 1 ~ Co ( eO + r COse~) de-
ThQn, the alloy compo~ition (percentage platinum%Pt(r)) for a point Pl at radiu3 r on the disc ~ub~rat~ i8
giv~n a~:
Pt (r) - 100 ~
Co ( ) Pt (
Al~o, th~ thickne~ o~ th~ d~po~itlon ~t a radius rl relative
to the thickn~3s at anothor radiu~ rO i9 approximat~d a~:
.
~1ckness (rl) ~ co(rl) ~Npt(rl)
Thickne~ (rO) NcO(rO) ~ Npt(r )
Th~ abov~ int~grals ar~ b~t ~v~luated u~ing standard nu~eri-
cal techniquse. Fro~ the~o int~grals, th~ p~rcentage concen-
tration o~ platinu~ at ~p~ci~iQd radial di~tanc2s from the
center o~ th~ ~uh trata m~y bo calcul~d. In add$tion, the
radial ~oncentratlon gradient May al~o b~ calculated and used
in predlcting the p~r~orm~nc~s o~ diw~ produc~d ~rom ~ given
target conf~guratlon.
A~ a 8p~Ci~iC ex~mpl~, th~ atomic p~rc~ntage conc~ntra-
tion of platlnum at polnt Pl, was calculat~d to be 5.0% when
th~ following para~et~r valu~ were u3ed:
~0 ~ 7.28~inch~D (18.49 c~)
r - 1 inch (2.54 c~)
~9~ 4~
29
SO = 0 in~he~ (o cm)
Sl = 6 . 076 inche~ (15 . 43 cm)
S2 - 6 . 3 00 inche~ ( 16 . 0 cm)
S3 - 1~ . O inche~ (30 . 48 cm)
h 2 2 inclla~ ( 5 . 08 cm)
Pt = 1. 14
c~o
The relativ~ putt~r rat~ for cobalt and platinum can
}: e estlmat~d~ ~ro~ pu~ ah~d tabl ~a o~ s~tes y~ds . ~o~
exampl~, at table 2, page 4-40 o:~ tha abov~-mentioned
Handbook o~ T2~ F~ C~}QlO~~ th~ 3putter yi~lds i~r
cobalt and platinum sputt~red ln ~gon with an ivn bombarcaing
~ne~gy Or 600 volts are gir~n a~ 1.4 and 1.~ resp~cti~ely.
The ratio o~ Cpt ~o Cco i~ then 1.14, a~ ~e~ i~orth abo~e~
Th~ abovQ calculat~d p~are~ntagQ conclantr~tion compares
well with ~n average m~a ured platlnu~n concentration o~ 4 . 89~
as measur~d by Ruth2rford sackscatter Spectro~copy, ~or a
sa~pIe which wa~ 3putter~3d ~ing the geometry d~scribed by
the param2ter valu~3~3 list~d abo~o.
: ~ Sputtering 3hi~1d3 240 ar~ also provided within the de-
position chambers to focu~ the d~po3ition on the ~ubstrate
and to shield other area~ o~ th~ cha~ er from undesired depo-
sition~.
The illustrated depoaition cha~er 20 i~ li}c~ chamber
14 and 18. How~svor, it m~y be a radio fr~sluQncy sputtering
chamb~r lik~ cha~bor 16. In thi~ oase, unlike chamber 16,
cha~er 20 d~po~it~ a wear re~stant matarial on substrate~
po~itionad thereln.
A~ an example, radlo frequ~ncy r~activo sputter~ng o~ a
cobalt-oxide wear layermay b~ e~ployed. In thi~ exampls, a
cobalt targ~t i~ u~ed and the cha~ber 20 i~ pres~urized to
approxi~ately 30von micron~ with a sputtering ga~ com~rised
o~ twenty p~rcent oxygon and eighty p0rcent argon. A typical
~puttering ti~e i~ 5.6 minute~ at two kilowa~ts power to the
sputtering target~. Thi~ r~ul~s in a wear lay~r o~ approxi-
mately fiv~ hundr~a an~troms. Suoh a layer ha3 provided
satls~actory wear r~8i~tanca when sub~ectad to ten thousand
:
. ,......................... ~ .
computer disc drive head start/stop cycleq. Alternately, as
another example, DC ~puttering may ba employed in chamb~r 20
to deposit a carbon wear layer a~ explained below.
Such wear layars provide protection to the underlying
layer~ depo it~d on the 8ub~trate8. In connection with
understanding thi~ wear protection, a~ume tha ~ub~trates
comprise magnetic r~cording di~cs used in computer disc
drives. Whenever th~ pow~r i8 shut off to an operating disc
drive, the rotating disc slows down and thQ head of the disc
drive ceases to fly and beginq to drag on the disc. The wear
layer increases thQ ll~a of tha di~c by minimizing wear from
the head dragging on the diac when powlsr is shut ofr.
B~causQ th~ chamber~ are isolatable ~rom one another as
explained above, the parameters affecting ~puttsring, ~uch as
sputtering ga~ pres~ure, sputt~ring ga~, ~puttering time and
power, in the individual aha~ber~ may ba optimized for the
particular ~puttering deposition b~in~ pQr~or~Qd.
Direct Curr~n~ Sputterin~ Chambers
Th~ deposition chambsr~ 14, 18 and 20 are best under-
stood with reference to Fig~. 14 and 15. Ele~ent~ in these
chambers which hav2 countarparts in thQ prev~ou31y de~cribed
spu~tering chamber 16 are nu~b~red with corrQsponding numbers
and there~ore will not be de~cribed in detail.
In the illu~tr~tQd Flg. 1 ~ystem, chambers 14 and la
are Qach de~ign~d to deposit chromiu~ layers, and cha~ber 20
is design~d to deposit a carbon lay~r, on ~ubstrate~ posi-
tioned ~ithin th~ chambers. Thi~ depo~ition i~ acco~plished
by direc~ curren~ sputt~ring. C~mmerc~ally availabla cathode
~puttering a~8emblias 40 may be utilized ~or this purpose.
For example, one suitabl~ asee~bly comprise~ a direat current
planar magn~tron ~putt~ring cathod~ availabla rrom Vac-~ec
Sy~tems and ~old under the trademark Fl~xi~ag. The~e cath-
ode~ have ~ive inch (12~7 cm) by ten inch (25.~ cm) rectangu-
lar water cooled, ~iv~ kilowatt rated targat~. Such cathodes
may be powered by commsrciall~ availabl~ ~ive kilowatt
ources, such as fPQ~ Advanc~d Energy System~.
~L~9~L443
AB shown in Figs. 14 and 15, two ~uch cathode assem-
blies 40 may be provided at the front and two at the rear of
the chambers. Al~o, the front and rear cathode aRsemblies
are at equal distances fro~ the plane containing substrates
260 in the ehambers. Referring to the right hand portion of
Fig. 15, the two front catho~e asaemblie~ 40 ar~ ~ecured to
th~ circular support plat~ 38 which in turn ls fastened to
the ~ro~t wall 92 of the depo~ition cha~er. Th~ cathode as-
sem~lies 40 are aool~d in a conventional manner via water in-
let and outlet line~ 198, 200 (Fig. 14). In addition, power
i~ deliv~red to the cathode a~semblie~ vla power cabl~s 248.
For purpo~e3 o~ ¢larity, tho water lines, and the uppermost
power cabl~s, ha~e bo~n eliminated ~rom the Fig. 15 view of
the~e cathod~ ~s~mblia~. Each o~ ths czthode a~e~blies 40
include~ a cathodQ housing 250 in~erted within a corr~pond-
ingly shaped opening through the ~upport plate 3B. A DC
sputtaring target a3sembly 252, including a target 254
mou~ted to a water cool~d iacket 256, i~ ~upportsd within th2
cathode h~u~ing 250. An in~ulator 25~ separate~ the cathode
hou~ing from the tar~et assembly. Clampa 2Sg hold asse~bly
252 in plac~. During sputtQring, ~at~rial i~ ~puttered from
the surfaco o~ target 254 to the ~ub~trates 260 as the
subs~rates ar~ carriod pa~t tha target by a carrier 220 (~ig.
19). Th~ t~rget~ 254 in chamb~rs 14 and 18 are of chromium
while the target~ 254 in chamber 20 are o~ aarbon. A cover
plate 251 ~nclo~s the cathode housing 250 wherQ it a~erge~
fro~ the support plata 38. Suitable ~eal~, som~ being
number~d a~ 242, ~eal the chamber~ 14, 18 and 20.
During a typical 3puttering process in the Fig. 14
chamb~r, the substratea 260 on carrier 220 are moved in a
planetary motion pa~t the targets 254. ThQ cklamber is
pre~uriz~d to approximately 7 microns with argon and a
plasma i~ ignited. When th~ targ~t~ ar~ aputtered at, ~or
example, an applied pow~r o~ approxi~ataly thrae hundred
volta and two amp~ ~or approximatoly ~iV4 minutes, a ~irst
chromtu~ underlayer of approxi~ately 3000 angstr~ms is
depoaited on the ~u~trat~.
~2~4~3
32
It has been found that the thickne~s of the chromium
underlayer hae an effact on the eoercivity of an overlying
cobalt platinum magnetic layer. That ie, with increasing
thicknes~es of the chromium underlayer, the coercivity of the
magnetic layer is increased. ~his coercivity increase~ at a
rate of about se~en o~r~tod~ per one-hundred ang~trom~ o~
chro~ium underlayer thickne~s. Thl~ increasing coercivity is
pro~a~ly due to an epitaxial s~fect be we~n the underlayer
and the cobalt platinum lay~r. ~y controlling the consisten-
cy o~ the thicknes~ o~ the und~rlayer from disc to disc,
additional control of the consistency o~ the coercivity of
the thin ~ilm magn2tie reeording dises i~ maintained.
Furthermore, by v~rying the thicknes~ of the underlayer in
the radial direction, a radial coQrciv~ty gradient may be
established in th0 re~ulting di~c. With the eputter~ng
cathode~ 40 positioned in the eonfigura~ion illustrated in
Fig8. 14 and 15, and with th~ sub~trate~ moved ln a planetary
manner during ~puttering, the re~ulting ehromium underlayer
$g somewhat thicker at in~er than ~uter radial positione of
the substratee. Th~refor~, thi~ ehro~ underlayer deposition
aleo eontrihutes to th~ pr~viou~ly described desired higher
to lower radial eoereivity grad~ent moving fro~ inner to
outer positio~s on the di~e~. ~k ha~ al~o been found that
the coereivity of the r~eulting thin ~ilm magnetic recording
discs i~ more pr2dictable and mor~ consi~tent ~rom disc to
disc, i~ the time betwe~n spultaring o~ th~ chromium
underlay~r and cobalt platinum }ayer i6 limited to no more
than about five minute~. With the sy~tem of the present
invention, this i~ ea~ily accompli~had because the ~ub~trates
ara readily tran~ar~ed ~rom cha~ber to chamber.
The chamber 18 in the pre~arr~d ~mbodim~nt is al~o uti-
lized to ~putt~r a chrome outer layer onto tha ~ubstrate~.
Thls chroma outer layer sQrve~ th~ ~unction o~ providiny an
oxy~sn di~usion b~rrier to protQct the cobalt platinum layer
from oxidation or corroslon. A chrome outer layer o~
approximat~ly 250 angstrom~ i9 ~uitabls ~or thi~ purpose.
Consequ~ntly, in c~a~ber 20, although ~hown wlth ~our cathode
asaemblies 40, only on~ ~ront and one rear assembly 40 are
~L~9~44~
~3
typically u~ed. With a two target chamber, thi~ outer layer
i~ deposited by sputtering the targets at, for example, an
applied power of approxi~ately 0.7 a~p and ~hree hundred
volts for two and onQ~half minutes. A seven micron arqon
sputtering ga~ environment i~ suitable.
In sputtering a carbon wear layer in cha~r 20, ~our
carbon cathode assemblies 40 are u~ed, two at the front and
two at the rear o~ th~ chamber. To produc~ a 400 angstrom
wear lay2r, the targ~ts are sputterea at, for example, an
applied power of approxi~ately thre~ amp~ and threa hundred
volt~ ~or three and one-hal~ minutQs. A seven micron argon
sputtering ga~ environment is al~o ~uitable for thi~ wear
layer depo~ition.
Although de~cribed above with speci~ic ~puttering
operation~ in the specific proces~ing chambers, ona can
easily replacs the previously de~cribed ~puttering a~semblies
with other vacuum deposition a~e~blis~ a~ de~ired. Thi~ is
readily acco~pli~hed by simply remo~ing the plate~ 38, 39 and
replacing them with plate~ conta~ning dif~rently con~i~ured
targets. Al~o, fewer or more deposition chamber~ may be em-
ployed depending upon tha number of layers to be deposited
onto a ~ubstrat~.
Mat~rials ~andlina Sv~tem
The materlal~ handling systQm ~or transferring and
handling thQ sub~trates during proc~ing i8 shown in Figs.
16 throuyh 28. Thi~ system includ~s the planetary 6ubstrate
carriers 220, one being ~hown in Fig. 19, for carrying sub-
strate~ 260 during proc~ssing. Another component o~ the ma-
terials handling system comprise~ rack~ or trays 270, one
positionQd in load cham~er 12 and on~ in unload chamber 22.
The tray 270 in the load cha~bQr 12 ~upport~ carrier~ 220
prior to proce~sing while the tray in the unload chamber 22
~upport~ carriers ~ollowlng proce~ing. In addition,a load
mechanlsm 272, and a aimilar unloading mechanlsm, are
provided in the re~pective load and unload cha~bers. The~e
latter mechani~m~ trans~r carri~r~ 220 to and from
transporter 222. ~ The transportQrs 222, tracks 224 and
tran porter drive assembl~es 226 compri3e ~urther components
~9~L~L43
34
of the materials handling system. In addition, the
plungers 228 and plunger drive 230, are also included in
the materials handling system.
Planetary Carriers and carrier SupPort Trav
In the system of the present invention, a carrier
means, such as carriers 220 (Figs. 19, 19a) are provided
for supporting the substrates for movement during
deposition in the high vacuum, high temperature
environment typically found in sputter deposition
chambers. In addition, such carriers impart a planetary
motion to substrates supported thereon while minimizing
particle generating from frictional engagement of metal
parts. This planetary motion enhances the uniformity of
deposition on the substrates because the substrates are
not continuously sputtered from the same region of the
target. As a result, this motion compensates for and
averages the effects of non-uniform sputtering from
particular regions of the target. Moreover, these
carriers permit simultaneous deposition of both sides of
the substrates 260 without requiring complex mechanisms
for turning the substrates over during deposition.
Furthermore, the carriers 220 are readily adapted to
support substrates of varying sizes.
With reference to Fig. 19, one form of planetary
carrier 220 comprises a circular planar pallet or
carrier chassis plate formed of aluminum or other
electrically conductive material. A central opening 276
is provided through the carrier plate. A hub 278 is
inserted through opening 276 and secured in place by a
hub clamp ring 280. The hub is engages by the load and
unload mechanisms 272 (Fig. 20), as set forth below, to
transport carriers 220 to and from the trays 270 (Fig.
17). In addition, the hub is engaged both by the
.!,,
1~3~4~3
34a
plunger 228 (Fig. 15) and by the transporters 222
during various steps of the process, as explained below.
Portions of the carrier plate 220 are removed to provide
plural, generally circular, ~puttering openings 282
through the carrier plate. A substrate supporting
structure is provided for supporting the substrates 260
in the openings 282 so that one surface of the substrate
is exposed
:,. ;
. ., . ~
~L2~
to sputtering target~ through th~a openings. A~ shown, the
substrat~ ~upport may be an integral part OI the carrier
plate and comprise plural thin ~poke~ 284 extending from the
perimeter of th~se opening~ to a central hub re~ioTI 286. As
shown, three such 8pOl~,Q3 may be employed and ar~ ~paced one-
hundred and twenty degraes apart about the hub regionL Sub-
Rtrates ~upportillg ~h~ave~ 288 are rigidly ~ecured by a fas-
tenar 289 to the hub r2glons 286 and ~uppor~ tha substrates
260 a~ shown in Figs. 17 and 19. Th~ 3heave~ are po~itioned
at equal radial di~tanc~s ~rom the cent:er of op~3ning 276.
The size of the openings 28~ is varied depending upon
the ~iz~ o~ the di~c3 being procee~ed. Thu~, lar~r and few-
er openings 282 are pro~,rid~d when larg~r disc~ ar~ handled by
the ~y~tQm. For examplQ, opQnings may b~ provided to handle
nine nin~ty-fiv~ millime~t2r di~cs, ~ix one-hundred and thirty
milll:neter discs, or three ~wo-hundred and ten mlllimeter
discs. The Fiq. 19 carrier 220 can accommodate thin, planar
trates of variou~ ~iz~ and ~hape~. All 1:hat is required
i~ that the substrate have~ a circular holQ concentric with
the center of gravity of th~ trate and sized to fit onto
a sheave 288. Thu~, while round sub~trate~ with concentric
hole~ are illustrated and pr~erred ~or the ambodlment de-
scribed, 3ub~tratea o~ virtu~lly any shape may be supported
in this manner.
The sheave~ 288 ara groov~d around their circum~erence
much like the groove provid~d in pulley wheQl3. The grooves
~re ~orm0d to acco~odate the thicXnes~ o~ the sub~trate to
be proce~3ad. With the plan~ of the carr~er plate in a ver-
tical orientation a~ ~hown, the grooves o~ the sheave~ are
also in a common vertical plan~. tn addition, substrate~
260, with interior hol~3 o~ a di~mater D2, hang ~ro~ the
groove Or the qheave~ and aonta¢t tha circular sur~aoe at the
base Or th~ shQavQ groove. Slnc~ ~ub~tr~te~ 260 merely rest
in the shQa~e groove~, loadlng and unlo~ding o~ ~ub~tratQs
260 onto the carrier 220 13 gre~tly ~impllried. This
circular ~heave sur~ace 1~ o~ ~ diameter Dl and is les~ than
D~. ~otation o~ the planetary carrler 220 at a preselected
speed about it~ center by the plung~r 228, as ~xplained
3L~9~
36
below, causes a corre~ponding rolling of the substrates on
the sheaves. For each revolution of th~ carrier, each
substrate 260 somplete~ a ~raction of a revolution on i~s
sheave given by th~ ratio Dl divided by D2. There~ore, the
orientation of the substrat~ z60 relative to a fixed
sputtering target i~ gen~rally dlfferent after each
revolution of the plan~tary. Similarly, the orientation of
the ~ubatrata~ 260 relativs to the ~pokea 284 continuously
varia~. A~ a rQsult, sputtering o~ the back ~ide o~ the
~ubstrates ~ay be per~ormed through the op~ning~ 282 without
the ~poke~ 284 leaving shadow~ on tha aub3trate3 and inter-
~erlng with the deposltion. Con~equ~ntly, ~imultaneous depo-
sition of ~aterial~ onto both sid~ o~ th~ disc ~ub~trate i5
po~ ible and the r~sulting disc ~urfaces have ~ub~tantially
uniform propertiaR.
Furth~rmore, circumferential uni~ormity o~ the depos-
it~d fil~ on th~ aub~trat~ i8 enha~c~d by this planetary mo-
tion. That i~, variatlons in sputt~ring by di~erent por-
tion~ of the sputtsring target~ tend to be averaged because
of the planetary tra~el o~ the sub~trate during ~puttering.
In addition, as previously expla~ ned ~n conn~ction with the
depo~ition o~ th~ cobalt platinum layer, layers with radial
film concentratlon gradiQnt~ may be ~puttered onto the sub-
strate~ to vary the radial coercivity in a de~ired manner.
Further~ore, thQ rolling Or th~ sub~trates on the sheaves re-
sult~ in ~ubstantially no contaminating particle generation
a~ each cubetrate ~imply roll~ in a ~h~ave groove a~ the
ghaave i9 rotated. In addition, ~uch a sub~trate carrier re-
qyire~ no lubrication. There~ore, contamination ~xom that
~ource i~ aliminated.
In addition, such a carrier 220 i~ relatively inexpen-
stve, i~ compatibla with simple load and unload tooling me-
chanis~, and i8 una~ectQd by hlgh temperature~ and high
vacuums encountered in typ~cal ~puttaring operations. As
~ention~d, the carrier plat~ i~ typically o~ alu~inum while
the sheav2~ 2~8, hub components 278, 280, and fasteners 289
are typically of s~inle3s st~l. The carrier pla~e i~ also
typically of ~tainle~ ~t~el or oth~r high temperature
~2~4~3
resistant material if the temperature of the deposition
process exceeds about one-hundred and eighty degrees
Celsius. The carrier 220 provides a ground plane for
grounding the substrates 260 and electrically isolating
the deposition environment, such as the sputtering
plasma in a two-~ided deposition process.
The carrier 220 shown in Fig. 19a also imparts
planetary motion to the substrates by supporting the
substrates for rolling within an annular groove as the
carrier is rotated. In this form of carrier, the spokes
284, central hubs 286 and sheaves 288 are eliminated.
Instead, a circular groove 283 of a cliameter Dl is
provided at the circumference of each of the circular
openings 282. As shown in Fig. 19b, each subs~rate 260,
of a diameter D2 which is less than Dl, contacts the
groove 283 and thereby rolls in the groove as the
carrier is rotated.
The Fig. l9a form of carrier is also suitable ~or
substrates of various sizes. In addition, the
substrates need not have a central opening. Howeverr
the outer perimeter of the substrate must be
substantially circular for smooth rolling action.
For each revolution of the carrier 220, each
substrate 260 completes a fraction of a revolution on
its groove given by the ratio of Dl divided by D2.
However, to provide stable support of a substrate
supported in this manner in a groove 283, the ratio of
~1 to D2 must be only slightly greater than one. This
requirement does not exist for the Fig. 19 form of
carrier because, in the Fig. 19 form with the center o
the disc 260 supported on a sheave 288, Dl and D2 need
not be close to unity for stable support. In general,
the greater the difference between Dl and ~2, the
greater the randomness of exposure of the substrate
. ._
~2~ 3
37a
surface to different regions of the target surface as
the carrier is rotated. Furthermore, the greater the
randomness, the better the compensation for non-uniform
deposition from different regions of a target and the
better the uniformity of the deposition. Thus, the Fig.
19 form of carrier has some advantages over the Fig. l9a
form of carrierO Also, somewhat higher partial
generation may re-
~;, .,
~,
.æl .
a3
38
sult from the Fig. l9a carrier than the Fig. 19 carrier.Otherwise, th~ Fig. l9a carrier posses~es the advantag~s and
~eatures previouqly explained in conn~ction with the de~crip-
tion of th~ Fig. 19 carrier.
Referrlng to Figs. 16, 17 and 18, the rack or tray 270
has a frame which include~ front and r~ar ~upport plates 296,
298. Three horizontal planetary ~upporting rod~ 300, 302 and
304 are support~d by th~ plat~ 296,298. Thq rod~ 300, 302
and 304 are eaah provid~d with plural axially spaced apart
annular groove~ 306. Each groove o~ each rod i~ aligned in a
vertical plan~ pa~sing through a corre~ponding groove o~ each
o~ the othQr rods. Further~ore, the plate3 296, 29~ ~upport
the rods so that corrQsponding groove~ o~ tha rods are po~i-
tion~d in an arc o~ a radiu~ which Qquals the radills of the
carri~rs 220. Consoquently, a~ ~hown i~ Fig. 17, the car-
riers ne3t within thQ corr~sponding grooves and are ~upported
at thr~e location~ by the rod Qcau~e th~ rod~ are po3i-
tioned beneath ~u~trata~ 260 ~upported on the carriers 220,
th~ po~ibility of aontamination of thQ sub~trate~ by par-
ticle~ ~rom tha rods i8 ~inimi~ed.
As ~hown in Fig. 17, a pair o~ parallel, horizontal,
3paced apart rails 308, 310 ar~ ~upp~rtod ~ro~ the floor 62
of chamber 12 and extsnd sub~tantially ~rom front to rear of
the chamber. Th~e rails ar3 parall~l to chamber walls 56,
58 and hava n upper tr~y engaging portion which i~ o~ circu-
lar cros~ section. Grooved rollors 312 are pivotaliy mounted
to the tray 270 and each engaga the upper por~ion of rail ~08
at two location~. Flat rollQrs 314 arQ also pivotall~
mounted to tho tray. Each rollar 314 Qngage~ the upper por-
tion of rail 310 ~t ons point. Thexe~or~, as the tray is
~lld on rail~ 308, 310 into and out o~ the chamber, the
roll~r3 312, 314 and rails 308, 310 coop~rate to establi#h a
plan~ which ~upport# ~h~ tray. Furth~rmora, rod 308 in co-
op~ration wlth roller~ 31Z d~in~ a lin~ ~long which tha tray
~lide~ into ~nd out o~ th~ chambar 12. Furthar~ore, a stop
316 (Fig. 16) li~it~ the d~pth o~ in~ertion o~ tha tray i~to
the chamber to a pa~ticular point. Con~eguantly, the tray is
easily and pr~ci~ely po~ltioned at th~ ~ame location each
lX~ 3
tim~ it i8 placed into th~ chamber. In addition, a stop 318
(Fig. 16) i~ mounted to the rail 310 following the posi-
tioning of th~ tray within the chamber 12. Stop 31~ prevents
th~ tray fro~ rolling toward door 68 after it is in position.
Note, for purpose~ of clarity, th~ sub~trates and ~heaves
have been omitted from the carrier~ 220 ~hown inFigs. 16 and
18. An identical tray supporting structura i9 also proYided
ln unload cha~ber 22.
L~--9b~L~ Ig~ sbanis~s
The loader 272 ~or loading carriers 220 from the tray
270 and onto th~ tran~port2r 222 1~ shown in Fig~. 16-22.
The unload chamber 22 i~ provided with an unloadar which is a
mir~or ~mage o~ the loader ln chamber 12. Con~e~u~ntly, the
unload~r will not be d~cribed in d~tail.
In g~neral, thQ loadQr 272 h g an upwardly extending
load arm 320 with a carrier handling finger 322 projecting
outwardly ~rom th~ fxe~ ~nd o~ ar~ 320 ~n th~ direction of
door 68. The arm 320 i~ ~upport~d at it~ lo~er end by a bel-
low~ block 324 which is capabl~ o~ v0rtical upward and down-
ward mov~ent. A bellowo 3~8~bly ind~cate~ generally at 326
(Fig. 21), and do~crib~d ln dotail b~low, i~ ~upplied with
air to shi~t th~ block 324, and th~reby th~ ar~ 320 and
finger 322, upwardly and downwardly~ Th~ bellows block 324
is mounted to a trav~ling body 330 which i~ 31ida~1y mounted
to a pair o~ spaGod apart upp~r and lower horizontal guide
rails 332, 334~ Rails 332, 334 are parallal to wa:Ll 56 and
extend ~ro~ the gront to the r~ar o~ the cha~ber. A hex
drivo ~crow 336 i~ coupled to.the travel~ng block 330, as ex-
plained below, and driven by a r~varsible step motor 338.
When driven, the driv~ ~cr~w ~hi~t~ th~ traveling block 330,
and thus the arm 320, eithar ~orwardly toward the ~ront o~
chamber 12 or r~rwardly.
Eloctrical drive pu13~ 9 d~ r~d to the ~tep motor
under tha control o~ tho computor 46. By ~onitoring ~he num-
ber o~ pulsQ~, th~ po~ition o~ tha travali~g block 330 and
arm 320 along the~guid~ rail~ ls known. ~n optional sha~t
encoder i5 utilized to ~onitor the rotation o~ the motor and
443
thus of drive ~crew 336. ~he shaft encoder provides feedback
to the computer of th~ movem~nt of kh~ drive ~crew in re-
sponse to the step motor pulse~. In addition, as e~p~ained
below, tha comput~r control~ t~ air which i~ suppli~d to a
pair o~ bellow~ 392, 394 (Fig. 21) which operat~ as axplained
below to rai~Q and low~r bQllow~ block 326. ~herefore, the
upward and downward movement o~ the ~r~ 320 i~ controlled by
the computer.
In operation, the loader i8 aapable of automatically
moving along a tray 270 o~ carriers 220 in oha~ber 12, re-
trisving a ~ingle carrier from th~ tray, and then loading the
retrieved carrier onto a transport~r 2a2. Thi~ operation ls
sequencad as ~ollow~. At th~ start o~ the ~equence, a trana-
port2r 222 is po~itionad out3id~ o~ tha ohamber 12. Also,
tha traveling block 330 i~ po~itionad a~ a ho~s po~it$on
ad;acent th~ x~ar wall 64 o~ th~ ch~mb~r 12, ~uch a~ ~hown
inFig. 16. Th~ traveling blocX 330 i~ th~n driv~n ~orwardly
by motor 338 until the ~ingar 322 i~ ert~d fully into the
hub 278 o~ th~ r~armos~ carriQr on th~ tray. The b~llows
block 326 i~ then raised to raisQ th~ arm 320. This causes
the finger 322 to contact thG hub 278 and li~t th~ carrier
out o~ the tr~y ~ The trav~l ing body 330, and thus the arm
3~0 and Yupport~d carrier 220, i8 then driv~n rearuardly to a
pc~ition which center~ th~ carrl~r 220 over the cent~r of the
track 224. Th~ tran~port~r 222 i~ then drlv~n into the cham-
ber 12 until upwardly axtending arm~ 340, 342 o~ the trans-
port~r 222 are positioned beneath th~ carrier hub 278. The
arm 320 is thQn lowsr~d by b~llow~ 392, 394 a3 explained
below, to cau~a the carrisr 2~0 to res~ on the ar~s 340, 342
o~ the transporter. The travQling bedy 330 iB then driv~n to
it~ homa po~ition ad~ac~nt to tha rear wall 64. Whan the
traveling body 330 1~ thu~ out o~ th~ way, tran~port~r 222 i~
mov~d to th~ next chamb~r and carria~ th~ load~d carrier 220
with it. A~ter the carrier 2Z2 ha8 exlted rro~ chamber 12,
the sequence i8 again r~pe~ted ~o ~hat, upon re~urn Or the
transport~r, the n~xt carrior i8' ln poaitlon ~r loading.
Thi~ ~equence i~ ~4peatad until ths l~t carr~er is loaded
on~o th2 transport~r and the tray 270 is e~pty. Then, the
443
41
~racuum 18 removed ~rom chamb~r 12 while chamber 14 is
isolated, the door 68 i~ openedr another tray o:e carriers is
insertad into chambar 12, and tha door is closed. Following
this, the vacuum i3 reeatablished in chamber 12 and loading
of carrier~3 from the tray ~nd onto th~ transporter is
continu~d .
Th~ detall~ OI th~ portion o~ the loader snechani~m 272
utilized ~or shifting the traveling body 330 along the guide
rods 3 3 2, 3 3 4 are shown in Fig . 2 0 .
~ sre speciIically, a cha~ber wall mounting bracket 343
is ~nounted to the chamber ~ide wall 56 as shown in Flgl 18.
The ~orward end o~ each o~ the guide rod~ 332, 334 i~
Iastened to the bracket 343 ~9 indicat~d ln Fig. 20 while the
raarward end o~ th~e rods i~ Ia t~n~ad to the r~ar cha~nber
wall 64. Upper and lower op~nlng~ 345, 344 ar~ provided
through the tra~teling body 330. }~all ~ushing~ ~not ~hown)
within the~o op~ning~ slidably r~ce~Y~ th~ ro~p~ctiva upper
and lower rods 332, 334. Tho hex drive ~cre~r 336 iE~ threaded
through an elongated nut 348 ~nd ha~ it~ forward end 350 sup-
ported by a bearing 352 in ~ bs~rin~ block 354 mounte~ to the
bracket 343. The nut 348 i9 ~ecured ts: a ~ount 356 and held
in plac~ by a cover 358. Mount 3S6 in turn i8 rigidly
mounted to the trav~ling body 330. Consequently, when drive
screw 336 ia rotatQd in a ~ir~t direction, th~ traveling
block shi~t~ in a ~orward dlr~cti~n along guide rail~ 332,
334. Conv~rsely, wh~n tha scrQw 326 is ro~ated in th~ oppo-
si~ dlr~ction, th~ ~raveling block ~hi~t~ r~arwardly.
Th~ driv~ ~crew 336 i8 couplQd to ~ha step motor in the
following ~nner. Tha rear end 360 Or ~crew 336 i~ connected
to a tor~ionally r~gid Plexibl~ coupling 362. Coupling 362
i~ conneated to and drivan by A ~ha~t ~nd 3G4 pro~ecting from
on~ ~nd o~ ~ commercl~lly ~v~ilabl~ s~led rerrorluidic
rotary faed through couplar 366~ Such ~ are co~mercially
available ~rom ~arro~luidic3 Corporatio~ undor thQ trad~mark
Ferro~luidic TM seal~. A 3ha~t end 36~ pro~e~ting ~rom the
other end o~ coupl~r 366 ~upport8 a hub in~ert 370 which is
conn~ct~d to a hu~371 o~ large diam~ter timing pulley 372~
A timing belt 374 couple~ timlng pulley 372 to a smallar
~9~443
tlming pulley 376. Pull~y 376 i8 driven by the step motor
338.
The coupler 366 is po~itioned within a s2aled hou~ing
378 (Fig. 16j ~cured to cha~ber wall 6d by a connector 380
(Fig~ 20). A c~ to hou~ing 378 i~ provided thr~ugh a plug
379 ~or tha purpos~ oP parmitting tightening o~ coupler 366.
The drive ~crew 336 pa~a~ through tha oha~ber wall 64 and
engage~ the couplar 366 within housing 378. Because the
coupler 366 is ~aal2d, rotaton i~ transmitted through the
coupler while a high vacuum i8 maintained within chamber 12.
Motor 338 i~ ~upported by a bracket 383 (Fig. 16) which is
mountad to houslng 378 by a motor mount 382.
Thu3, ~tQp ~otor 338 i8 oparatlvely couplad to the
drive screw 336 for rotat~on o~ th~ 3crew in either dir~c-
tion. In addition, the po~it~on of the tra~eling block 330
along the guide~ 332, 334 relativ~ to a referenc~ location
may be deter~ined ~ro~ the nu~ber o~ driv~ ~tep~ through
which the ~crew 336 ha~ be~n dri~n by the step ~otor. Fur-
thermore, th~ ~tep~ ar~ ~lectrically controlled and monitored
by the comput~r 46 80 that tha po~ition o~ th~ traveling
block is known.
. Th~ bellow~ block 324 i~ raised and lo~red by alter-
nately ~ressurizing bellows 392, 394 (Flg. 21) to thereby
rais~ and low~r th~ arm 3~0. The vertical ~otion of b~llows
block 324 i9 guide~ by a pair o~ verti~al pin~ 384 (Fig~. 16,
20), mount~d with~n the traveling body 330. The~e pin8 ex-
tend through v~rtical op~ning~ 386 through the b~llows ~lock
324. Pin~ 384 are slidably coupled to the bellow~ block by
bushing~ 388~ one being ~hown in Fig. 20.
A~ ~hown ln Fig. 21, tho bellow~ a~embly 326 includes
an upper ~tainl~s~ ~t~el b~llow~ 392 mount~d by bellows
holding clamps 3g3 to an upp~r sur~ace o~ the bellows block
324 with a ~ealiny ga~k2t poeltioned b~twaen th~ bellow~ and
block. A ~imil~r lower bellow~ 394 i~ mount~d in the sama
~anner to ~h~ undar~ld~ o~ th~ bellow~ block. Thes~ b~llows
are suitable ~or operatlon in a high vacuum environment wi~h-.
out 1 eaking ga~ ~r~ th~ bellow~ into the ~nvironment. When
the bellows block 324 and travsling block 330 are a~se~bled,
~X9~443
43
the upper bellows contacts an upper surface of the
traveling bl~ck while the lower bellows contacts a lower
surface of the traveling ~lock. Tharefore, when the
upper bellows is pressurized, the bellows block 324 and
attached arm 3~0 are shifted downwardly. Conversely~
when'lower bellows 394 is pressurized, the arm 320 is
raised.
Pressurized air for operating the bellows 392, 394
is delivered by a pair of air lines (not shown) which
pass through an upper ~eed through housing 396 attached
to the chamber wall 56 (Figs, 17 and 223. As gasket
seals housing 396 to the wall 56. A flexible stainless
steel bellows conduit ~98 is connected from the upper
housing 396 to a lower bellows feed through housing 400
mounted to the bellows block 324 lFigs. 17 and 21). A
gasket 426 seals housing 400 to the bellows block 324.
The air delivery lines pass through conduit 398 and
enter housing 400.
To connect the conduit 398 to the feed through
housing 396, a cylindrical insert 402 (Fig. 22) is
inserted within the end of conduit 398 and a compression
ring 404 is then forced over the outside of the conduit.
A retainer plate 406 holds the compression ring, and
thus the attached conduit, to the underside of the feed
through housing 396 with a gasket seated between the
housing and compresæion ring. The lower end of the
conduit 398 ~Fig. 21) is connected to the lower bellows
~eed through housing 400 in the same manner by a
respective insert 410, compression ring 412, gasket,
and retainer plate 414.
43a
A first of the air lines entering housing 400 is
connected to a flow controller 416 which extends into
an opening ~17 in an air flow block 418 and communicates
through the block and an aperture 420 with the interior
of upper bellows 392. The second of the air lines
entering housing 400 is connected to a flow controller
422 which extends into an opening 424 in the air flow
block and communicates through an aperture (not shown)
leading to tha interior of bellows 394. Flow
controllers 416, 422 permit unrestricted flow into the
bellows and restricted flow out of the bellows to smooth
the lifting and lowering movement of the arm 320.
~LZ9~L443
44
To lower the arm 320, a solenoid operated computer con-
trolled air valvo is op~ned to permit the flow of air through
the first air line and into th~ upper bellows. To lower the
arm 320, another comput~r controlled Rolenoid operated air
valve i~ opened to permit the flow o~ air into th~ second air
line and into the lower b2110w3.
Plun~er and Plun~er Drive ~echanism
The detail~ of the plunger 228 and plunger drive mecha-
ni3m 230 can be und~r~tood with rQ~erenc~ to Figs. 10 and 26-
28. The plunger 228 i~ de~igned to accompli~h three func-
tions. First, it is movabl~ axially to po~ition the carrier
gripping tip 232 o~ th~ plunger lnto tha hub~ 278 o~ the
planatary carrier~ 220 (Fig. 19) when each carri~r i8 pogi-
tioned by a transportar 222 in alig~m~nt with th~ tip of the
plunger. Following in ertion, the plunger grlpping ~ip 232
is operated to grip the hub o~ kh~ planetary carrier and lift
the carrier upwardly from th~ tran~portsr. Lifting and
clamping action i~ acco~plishad util~zing rolling contact
bçtwee~ ~urfac~s of khe plunger tip an~ interior o~ the hub.
That i~, t~ plung~r tip ha~ a minor ~h~ft with ~ccentrically
mounted baaring~ which ar~ rotat~d rQlativ~ to a ma~or sha~t
with a fixed protru~ion. A~ thi0 rotation occurs, th~ di~-
tance betwesn the b~aring and protrualon increa~es until
these elements grip the int~rior of the hub and li~t th~ hub
from the tran~port~r in one contlnuou~ motion. Then, the
plunger i~ rotated by th~ plung~r driv~ machanism 230 during
sputtering to ~hor~by rota~ th~ carriQr ~20 and move the
3ubstrate 260 a~ pr~viou~ly explained. A~t~r sputter~ng, ro-
tation is stopped. Th~ carri~r 220 i~ then lowered onto a
tran~porter 22~, and the carrier 220 1~ rel~a~ed ~rom the hub
278 in one ~otion and the plunger is withdr~wn ~ro~ the hub.
~herea~ter, the tran~portor tr~n~ar~ th~ carrler to the next
chamber ~or ~urth~r proc~ing.
Th0 clamping and li~ting action o~ the plunger tip 232
is illu~trated in Fig~. 26 and 27. Speci~ically, the plunger
228 includes a ~a ~ r outer ~ha~t or ~pindle 436. A ~ixed
protru~ion 438 pro~ects outw~rdly ~rom a portion o~ the peri-
'a3
phery o~ the front face of the end of ma~or shafte 436.~hu~, the protrusion 438 is offset from the central longitu-
dinal axis of the shaft 436. More than one ~uch protrusion
may be utilized if de~ired. A rotatable minor shaft 440
(Fig. 28) Qxtends within the ~ha~t 436 and has its
longitudinal axis parallel to, but off-center from, the
longitudinal axi~ o~ th~ maior ~ha~t 436. Ths outer end of
shaft 440 term$natee in a head 442 ~rom which an eccentric
pin 444 projects. Bearings 446 and ~n outer bearing shield
448 are secured to thi~ pin and thereby hav~ centers which
are eacentric to thQ longitudinal axis o~ the minor shaft.
An air actuated cylind~r a0~embly 470 (Fig. 28) is
operatively coupled, as explainad balow, to th~ minor shaft
~40 ~or rotat~ng this ~ha~t. As the ~inor ~haft 1~ rotated
relative to ~a~or sha~t 436, th~ di~tancQ or sep~ration
between the center of thQ pin 4~4 and ~ha out~ide surface of
fixed pro~ection 438 increase~ a~ shown movin~ fro~ Figs. 26
~o 27. ~ha splndl~ or plunger ~ip 232 has its longitudinal
axi~ disposed in a horizon~al line nonmal to the plane of
carrier 220. Prior to in~ertion o~ the plunger tip into the
hub 278, tha minor ~h~t i~ ~irst rotat~d relativa to the
ma;or sha~t to an orientation which ~ini~ize~ the distance
between th~ c~nter o~ pin 444 and th~ outer ~ur~ace of
protrusion 438, as ~hown in Fig. 26. The tip 232 is also
rotated, by a motor 510 a~ explained below, to position
protru~ion 438 in a down position, beneath pin 444. This
provides maximu~ clearance ~or ~asy insertion o~ the tip 232
into the hub. Thu~ oriented, the tip 232, includ mg
pro~ection 43~ and pin 444, i~ insertod into tha hub ~78 of a
carrier 220. After insertion, th~ minor ~ha~t 440 is rotated
relativ~ to the maJor ~ha~t 436 to bring th~ baaring 446 into
rolling contact with thQ lnner sur~aca o~ the hub 278 and
li~t thQ carrier 220 ~rom it~ ~upporting transportar 222.
Additional rotation og th~ minor sha~t 440 cau~es further
li~ting o~ the hub until eventually the carrier hub 278 i8
cla~ped and ~ripped by the bearings 446 and ~ixed pro~ection
448. The eccantri~ b~arings 446 are prevented from rotating
over the center of the m~or ~har~ 436. That is, the
~9~443
46
interior aurface of the hub 278 i9 ~ized to be gripped by
projections 438 and bearings 446 before the b~aring~ ~ove to
an over c~nter position. When engaged in thi~ manner, the
hub pre~ent~ further rotation of the minor shaft 440.
Aft~r the cla~ping and lifting action i5 complete, and
the tran~porter 222 is moved away ~ro~ th~ ~puttering targets
in a chamber, the plung~r drive ~echanism 230 rotate~ the
major shaft 436 and ~h~ supportQd carrier during ~he d~posi-
tion process. Upon completion o~ proce~sing, plunger tip 232
i8 stopped, with the protru~ion 438 in its down positlon, in
the ~ams orientation a3 when the tip was in~erted into the
hub 278. In addition, tran~porter 222 i~ po~itioned under
the hub 27a of the plung~r supported carrier 220. Th~ minor
shaft 440 i8 th~n rotat~d in ths oppo~ite dir~ction fro~ that
pre~iously described to lower the hub onto the txansporter
and r~lea e the hub. The plungsr tip a32 i~ th~n withdrawn
fro~ th~ hub 80 that th~ tran~port~r 222 may transfer t~e
carrier to another chamber.
Ther~ are a numb~r o~ advantag~ to thi~ type of
plunger. First, there ar~ tring~nt r~guirements ~or
po~i~ioning o~ a tran porter 222 and it3 suppOrted plane~ary
carrier 220 in a chambsr. That i8~ the hub 278 need n~t be
perfectly align~d with the cent~r o~ tha plung~r tip 232 in
order ~or th~ plunger tip to bo in~arted into the hub. More-
over, becau3a o~ thQ po~ive cla~ping action by the plunger
tip, good ~l~ctrical aontact i~ mad~ between th~ plunger 228
and the hub 278. During ~puttering, a~ previously ~en~ioned,
grounding of the ~ub~trates i~ acco~pli~hed through the
carrier and plunger. Also becau~e o~ the po~itive clamping
action, the rotating carrier will be m~intained in a vartical
plane, perpendicular to th~ longitudinal plung3r axis. Thi~
~inimizee di~c suhstrate wobbling, motlon out o~ a vertical
plane, in the ~heave groove~ ~nd thu~ Minimizes thi~ poten-
tial ~ource o~ unde~irabl~ particles. Al~oj ~uch wobbling
could modulato th~ ~putt~rin~ by p~riodically moving certain
areas o~ the substrate3 clo~ar to the sputtering targets and
thereby cau~ing a ~riation in tha thicXne~ of the deposi-
tion on euch ~ub~trate areas. Finally, ~his clamping action
~91~43
47
eliminate~ relative rotation between the hub 278 and plunger
tip 232 during sputtering to thereby eliminate partial gene-
ration that could otherwise result ~rom such relative
rotation.
Referxing to Fig. 28, the minor ~haft 440 is rotata~ly
~upported within the ma~or sha~t 436 by a pair of bearings
450 separated by a spacer 452. ~a~or shaft 436 extends
through the wall o~ ths depo~ition cha~ber. A coupler 454
connects the inner end o~ th~ minor ~ha~t to a BtUb ~haft end
456 of a commercially available s~aled rotary motion ferro-
~luidic ~ee~ through coupl~r 458. An 0-ring ~eal, not ~hown,
is provided to seal ~ead through 45B at its connection to
~ha~t 436. The other ~tub shart end 460 o~ the reed through
is coupled by a ~ushing 461 to an elongated dri~Q screw re-
ceiving h~lix nu~ 462. As a re~ult, rotation of ~he helix
nut 462 cau~Qs the stub ~ha~t ~n~ 460, 456 and t~ minor
s~aft 440 to rotat~ and thsr~by producas th~ preYiou~ly de-
scribed cla~ping action. Th~ feed through 458 and helix nut
462 are po~itioned within ~ hollow Qxternal ma~or ~haft ex-
tension 464 (seQ al~o Fig. 10) to ~hich a plunger rotating
drive pulley 466 is ~ixedly mounted. A pneumakic actuator
mounting collar 468 i~ ~ixQdly connected to pulley 466. The
shaft extension 464 i8 threadedly connected to ma~or ~ha~t
4 3 6 . A ga~k~t i8 provid~d between the~e two 3ha f t component3
where they ~oin together.
A computsr controll~d ~olenoid actuat~d pneumatic
cylinder as~embly 470 i~ coupled by collar 468 to the drive
pulley. ~he pneumatic cylinder a~sembly 470, a~ explained
below, i~ designad to ~electively rotate the helix nut 462 to
cause a corre~ponding rotatlon o~ the minor ~ha~t and, there-
by, the plunger li~ting and clamping actoin. More specifi-
cally, the pn~umatic cylinder a~embly 470 includes an
actuator or pi~ton cylinder body 472 clamped in place by col-
lar 468. A piston a~aembly i~ poaitioned wlthln body 472 and
include~ a pi~ton head 474 to which a pi~ton rod, having a
~irst exten~ion ~ectisn 476 and a second drive screw section
478, i8 mounted. ~ ~lat sidQd ~lot in the end o~ extension
~ection 476 ~it~ over the ~n~ o~ drive ecr~w section 478 such
~g~4~3
48
that linear movement of piston head 474 results in linear
movement of drive screw section 478. Drive ~crew section 478
comprises a non-rot~ta~le high helix drive screw ~hich is in-
serted into the rotatable helix nut 48 whQn the apparatus i~
assembled. As tha piston head 47~ slid~ within the body ~72
toward the collar 468, the drive screw section 478 rotates
helix nut 462 relative to ma~or ~hsf~ 436 and also rotates
the minor ~haft 440 relative to th~ msjor ~ha~t. Thi~ con-
~erts linear motion o~ the pi~ton into pivoting motion of the
minor ~ha~t. A pi~ton retuxn ~pring 480 ~iases pi~ton head
474 in the oppo~ite direction away ~rom collar 468. Guide
pins 482, in~erted through internal bore3 o~ th~ piston head,
guide the sliding mov~ment of the pi~ton head. Thes~ guide
pin~ 482 al30 pre~ent rotation of the pi5ton head relative to
the shaft p~rtion~ 436, 464. The ~nd o~ body 472 i~ closed
by a valve body 484 to which a ~urc~ o~ air i~ coupled by a
rotary air union 486. A pair o~ ~low controls 488, like con~
trol~ 416, 422, control the ~low o~ air through val~e body
484 to the interior o~ the body 472.
~ computer actuated solenoid controlled air valve is
operated to deliver air to a~ bly 470 as required to shift
drive crQw section 478 ~orwardly toward th~ spindle tip.
Thi~ rotat~ thQ minor sha~t 440 ~o a~ ~o li~ and cla~p the
carrier 220. ~h~ co~puter al~o conkrol~ thl~ air valve to
relieve air pr~sur~ fro~ th~ p~ton head 474 a~ required to
lower and r~ e th~ carrior 220. Wh~n air pressurQ is re-
li~v~d, pring 480 ~hi~t~ drivo ~crew s~ction 478 rearwardly
and cau~s the lowering and relea~ing o~ th~ carrier.
The plungQr drive a~sQ~bly 230 includs~ a chamber wall
attachm~nt plate 490 which i8 mounted to tho r~ar wall o~ the
deposition chamb~r a~ ~hown in Fig. 10. Three horizontal
guide ~ha~t3 492 pro~ect outwardly ~rom plat~ 490 and away
fro~ the depo~ition ch~mbor. A ~otor carriage plate 494 is
slidably mount~d to the ~nds o~ tha guide ~ha~ts 492 a~ter
th2 carriags plata 494 i~ po~i~ion~d on th~ guid~ ~ha~ts.
The carriage platQ 494 1~ ~aalQd ko the rear chamber
wall by a flexible~bellows 500. In addition, a rotary Rha~t
vacuum seal 502 i~ po~ition~d within an annular projection
~9~443
4g
504 of the carriage plate 494. Shaft extension 464 extends
through the rotary seal 502. A pair of 0-ring gaskets ~ur-
round shaft extension 464 to seal th~ ~pace between this
shaft extension and the interior surface o~ saQl 502. A pair
of external o-ring gask~t~ ~shown in Fig. 28, but unnumbered)
surround seal 502 to sQal the space between 5~al 502 and the
carriage plate projection 504. Rotary ~eal 502 permits rota-
tion of shart 464 and thsreby the rotation of the major shaft
436. This results $n a corresponding rotation of a supported
carrier 220 during sputtering. Because of the sealing accom-
plished by seal 502 and bellows 500, the deposition chamber
is ~ealad against leakaga through the plunqer drive as~2mbly.
Axial ~hifting of the plunger 228 to in~ert and with-
draw the plunger tip 2~2 i~ acc~pli~h~d by a pne~matic
cylinder 506. Cylinder 506 has ita hou~ing connected to the
carriagQ plat~ 494 and it~ pi~ton rod connacted to the plate
490. A computer controlled ~olenoid actuated valv~ delivers
air thro~gh a flow controller S08, like c~ntrollers 416, 422,
to cylindar 506 to extend and rotract the piston rod as re-
quired. When th~ piston rod i~ retracted, the carriags 494
i~ shifted axially toward the depo~ition chambex and the
plung~r tip 232 is in~erted into th~ hub of a carrier. In
contra~t, when tha pi~ton rod i8 ext~nded, the carriage is
shifted in the opposite directlon and the plungsr tip is
withdrawn ~ro~ the hub. ~ellow~ 500 provide~ a vacuu~ ~eal
while permitting the axial motion of th~ plung~r tip,
A plungor rotatlon 3tep ~otor 510 is mounted by a
mounting block 512 ~o th~ carriagQ pla~e 494. When he mo~or
510 i9 snQrgizQd by ~lectrical pulse~, a drive pu~ley 514,
mount~d to tha motor ~ha~t 516, rotat~ in steps. Drive pul-
loy 514 i3 coupled by a ti~ing b~lt 518 (~e~ Fig. 10) to the
pullay 466 mounted to the sha~t 464. Consequently, wh~n the
motor 510 i8 opQrated, th~ oxten~ion sha~t 46~ and its con-
nected ma~or sha~t 436 rotats. Consequcntly, whan a carrier
220 i~ gripped by the plungr tip 232, motor 510 i9 operated
to rotate the carrier and mov~ ~ubstrate~ 260 on the carrier
in a planetaxy ~as~ on pa~t ~puttering target~ in the cham-
ber.
The computer 46 controls the electrical drive pulses
transmitted to motor 510. These pulses are monitored and
counted to determine the degree and rate of rotation. Also,
feedback to the computer is provided by signals from an op-
tional conventional shaft encoder. This shaft encoder in-
cludes a reflector 522 coupled by coupler 520 to the motor
shaft. A conventional optical through beam sender 524 senses
the position of reflector 522 and thus of the motor shaft.
Signals from the sensor 524 are transmitted to the computer
and used to track the shaft position and thus the rotational
position of the plunger. Therefore, for example, the plunger
may be rotated to always position protrusion 438 in its down
position following processing so that the plunger tip 232 is
in position for easy withdrawal from a carrier 220 and inser-
tion into the nest carrier.
Transporter, Track and Track Drive Mechanisms
The transporter or robot 222, track 224, and track
drives 226 are shown in Figs. 15, 23, 24, 24a and 25. These
mechanisms are designed to transfer carriers 220 from one
chamber to the next chamber when the valve housing 26 between
the chambers is open.
In general, a transporter 222 includes an elongated
body 530 (Figs. 23, 24, 25) supported at its front and rear
ends by respective wheel supported trolleys 532, 534. These
trolleys travel along the track 224 from chamber to chamber.
The transporter arms 340, 342 are vertically extending,
parallel, spaced apart, and are mounted at their bases to the
respective sides of the body 530. Each of the arms is
provided with a respective arcuate cradle or saddle 540, 542
at its upper end. The hub 278 rests in these cradles (Figs.
23, 24) with the carrier 220 positioned between the arms,
when the carrier is loaded onto the transporter 222. The hub
ring 280 and a section 544 of hub 278 act as spacers to
maintain the separation between the carrier 220 and the arms
340, 342.
As shown in Figs. 23 and 25, the arms 340, 342 are dis-
placed from the center of the trolley body 530 toward one end
1~9~43
51
of the body. With this construction, following the
loading of ~ carrier onto a plunger in a processiny
chamber, the transporter 222 is moved to a parked
position adjacent wall 58. Thi moves the arms 340 and
3~2 out of the way of the sputtering targets so that
there is no need to remove the transporter from the
chamber prior to sputtering, if desired.
Each of the trolleys 532, 534 is pivotally mounted
to the underside of the body 530 as shown in Fig. 25.
That is, a shoulder screw 5S0 mounted thereon is
inserted into a recess at the underside of the trolley
body~ A cover plate 556 holds this assembly within the
recess. The lower end of screw 550 is threaded into an
opening 558 formed in the upper surface of a trolley
~5 b~dy 560 of the trolley 532~ An annular spacer 561
maintains a separation be~ween the elements 530 and 560.
Trolley wheels 562, which comprisa bearings, are each
press fit onto a dowel S64 which is then pressed into an
opening 566 of the trolley body to secure thP wheel to
the trolley. This construction also allows for
compliance along the plane of the track since each
trolley pivots on its own center. The trolley also is
provided with non-metallic bumpers 568, 569.
The ends of a track in a chamber are spaced from
the respective ends of the tracks 224 in adjacent
chamber~. Thus, a gap exi9t5 :Ln the tracks batwaen the
chambers. These gap~ are located within the isolation
valve housings 26 and the valves 110 (Fig. 7) slide in
these gaps to close and .isolate the chambers without
interference by the tracks. This arrangement of two
trolleys per transporter 222 enhances the smooth
transfer of the transporter across these gaps between
tracks 224 in adjacent chambers. Also, the distance
~, ~
P , 1
129~4~3
51a
between the front and rear sets of wheels of each
trolley is greater than the distance across the gap.
This facilitates travel of the trolleys across the gaps
without skipping.
The track assembly 224 comprises an elongated
straight rigid trolley supporting track 580 supported at
walls 56 and 58 by track mounts 582, 584. A trolley
receiving recess 586 is formed in the upper surface of
the track 580 and is bounded by ~irst and second track
side walls 588, 590. The
, . . .
~ '
~a.Z9ï~
52
trolleys 532, 534 fit within thi3 rece~ and are guided in a
linear direction along the longitudinal axi~ o~ th~ track by
the side walls 588, 590. The bumper~ 568, 569 guide the
trolley~ along the trac~ and prevent unde~irabl~ particulate
generating ~tal-to-metal contact b~tween the trolley 560 and
tracX wall~ 588, 590~ The track ~ positioned in the cham-
bers to guide the transporter 222 and ~upported carrier ~20,
with the support~d sub~trate3 positioned in a plane centered
between tha front and rear ~putt~ring target assemblies 40 or
42. This enhancas the unl~orm sputtering of the s~strates
260 during th~ previou~ly describ~d deposition processes.
Fir~t and second elong~t~d cover strip~ 592, 594 ara moun~ed
to the upper surface~ o~ th~ r~p~ctive walls 5a8 and 590.
Covers 592, 594 pr~vent th~ trolley~ from li~ting upwardly
out o~ tha track. An elongated chain guiding slot 596 is
providad in th~ ~loor o~ th~ rece~s 586. Another such chain
guiding ~lot 598 i~ providsd at khe undar~id~ of the track
580 ~or purpose~ expl~i~ad below~
The transport~r 222 i~ driY~n along the track by a
chain driva mechan~sm 226 a3 follows. Spsci~ical~y, as ~hown
in Fig. 23, a contlnuou~ loop o~ chain 600 spans the ~amber
and i~ supported at its re~p~ctiv~ ~nd~ by toothle~ pulleys
602, 604. From pulley 602, thQ low~r sectoin o~ the chain
pa~C~s over and i~ drivanly ~ngagad by a drive sprockQt 608.
An idler wheal S10, in coop~ration with th~ pull~y 602, main-
tain~ the chain 600 in contact with thQ driva ~procket. The
810t 596 provide~ clearanc~ ~or th~ chain 600 where it passe~
over the drivQ sprocket 608. The pullsy 604 i~ mounted to a
~ensioning block 612. ~lock S12 i~ ~hirtabl~ toward and away
~rom wall 58 by a te~sion ad~ust~ent ~crew fil4 to ~hereby
ad~ust tha ten~ion in the chain 600. Other optional chain
ten~ian ~d~ustment ~echani~m~ are egually suitable. For
example, pulley 604 may b~ ~t~tionary ~nd idler wheel 610 may
be ~ovable to ad~ust the chain ten~ion. A ch~in guard 616
mo~nted to ths und~r~ide o~ thQ track 580 guid~ the travel
of th2 lower ~ection o~ th0 chain. In addition, the upper
section o~ the ch~4n 600 pa~e~ through the chain guiding
slot 596 and und~rneath tho rQ~p~ctive trolleys 532, 534.
~Z9~3
53
Each of the trolley bodi~ 560, a~ shown in Fig. 24a, has a
row of downwaxdly projecting chain engaging ta~th 620. These
teeth travel in th~ ~lot 596 (Fig. 24) and are engaged by the
upper ~ection o~ the driva chain. Con~eguently, when the
chain is driven in either direct~on, th~ transporter 222 is
correspondingly driven.
The samQ link (i.~., 622 in Fig. 24a) alway~ engages
the same tooth of a transporter in thl~ cha~ber. ~herefore,
by monitoring the po~ition o~ thi~ link, the poBition of the
transporter in the chamber i~ known. The transporters have
~our positions within a chamber, corr~ponding to four posi-
tions of the link. The~e po~ition~ include a load po~ition
in which the hub 278 i8 centered on the plunger 228, a parked
po~ition in which the tran~porter i~ mov~d ad~acent ~o a wall
58 to shift tha arm~ 340, 342 out Or the way of the ~put-
tering targets, a rear crossing po~ition in which the trans-
porter i~ positioned for a tran~fQr to the left, and a ~or-
ward cro~sing po~ition in which th~ trans~orter i8 po~itioned
for a trans~er ~o tha right. In addltlon, tw~ positions of
the link ar2 u~d when a tran~porter i~ not engaged on the
chain containlng th~ link. ~he~e additlonal link positions
include a rear cro~sing offs~t, in which tha chaln i~ posi-
tion~d for entry o~ a tran~porter from a cha~ber to the le~t
(l.e. in Fig. 23), and-a forward cros~ing of~aet, in which
the chain is po~itionQd ~or ~ntry o2 a tran~porter from a
chamber to thc right.
In ~ l~ft to right tran~ar (a~ shown in Fig. 24a), the
track chain in the right chamber is shifted to its rear
cro~sing o~et. Then, the track chain in the left cha~ber
i~ shi~ted to it~ forward crossing position which po~itions
the rorward ~-ooth 620 to tha point Or contact with the chain
link which is b~yond the link 622. As chown in ~ig. 24a, the
receiving ahain i9 in a prop~r poBition wh~n thQ top Or the
roller link 622 i9 spac~d ~u~t b310w ~axaggerated in Fig.
~4a) the lower edg0~ o~ ~irst kooth 620. ~hi~ alignment re-
duce~ the wear and the potential binding of the chain. After
th~ transportQr is~riv~n to the right, to the point of con-
tact as pr2viously dQ~cribed, the chain driva in the left
~291~43
54
cha~ber is haltsd. The chain drive~ in the left and right
chambers are then driven simultaneously, in synchronization,
in a direation whioh mvv~ the transporter to the right and
into the right chamber. In a right to left transfer, the
track chain in the left chamber i~ po~itioned at it~ forward
crossing offset. Then, the track in th~ right chamber is
positioned at it~ r~ar cros3ing po~ition. Ths chain dri~es
are again ~imul~aneou~ly dri~en i~ ~ynGhronizat~on to drive
the transporter into the left cha~ber.
The 3am~ link (i.e., link 622 in Fig. 24a) alway~ en-
gages tho ~ame tooth o~ a transporter.
With referenca to Figs. 15 and 24, th~ drivo ~ochanl~m
226 includes a st~p moto~ 626 driY~nly conn~cted by a b~lt to
a drive pulley 628. ~h~ pull~y i~ coupl~d through a rotary
seal 630 to a flexible coupling 632 located within the cham-
ber. A~ shown in F~g. 24, the ~l~xibl~ coupling 632 ls con-
nectad ~o the drive ~prockot 6~8. There~ore, when the ~otor
626 is operat~d ~o driv~ ~h~ drive sprockst ei~her in the
clocXwisa or co~nterolockwi~e dirQctlona, the chain i9 driven
in the corresponding direction. The computer 46 control~ the
transmission o~ driv~ pul~es to th~ motor 626. By counting
these pulse~, the computer track~ the po~ition o~ the chain
link~ 622 and thus the po~ition of transporters 222 in the
system. ~ shaft encoder (not shown, but integral with the
motor) i~ utilized to monitor the move~nt of the mokor drive
sha~t in a con~entional manner. Signals from the shaft en-
coder are tran~mitted to ths computor to proYid~ feedback o~
the position o~ the chain within th~ chamber. Of course,
limit ~witche~ ~r optical detectQr~ may al80 be used to moni-
tor the posltion~ o~ thQ tran~portQr.
A singlo tran3porter 222 may b~ utilizad to trans~er a
carrler 220 from tha lo~d chamber 12 through the daposition
chambers 14-20, and to the unload cha~ber 22. In this case,
a~er the carrier i8 unloaded in cha~ber 22, this transporter
i9 raturned to chamb~r 12 to rec0ive the n~xt carrier. How-
ever, ln th~ illu~trated prsferred embodiment, to sp~ed the
processing, three ~ch transporter~ ar~ e~ployed. The ~irst
transport~r ~rav~ls between cham~er~ ~2, 14 and 16. The
~9~443
second transport~r travel3 between chambers 14, 16 and 18.
Finally, tha third of these tran~porter~ travels between
chambers 20 and 22. Therefore, under the control of computer
46, certain of the transporter~ ar~ tran~porting carriers 220
in certain part~ o~ the sy~t~m whila other tran~porkers are
transporting other carrier~ elsewhere in the sy~tem.
Nater Coolinq Syst~3m
The water cooling syatem ~or the cathode a~semblies 40,
42 in the processing chamberR 14 through 20 i9 ~hown in Figs.
29-31. The Fig. 29 cooling ~y~tem i3 a clo~ed loop sytem.
Alternately, water ~rom ~ municipal water supply or other
~ource may be util~zed and r~tur~ed to the at~rm drain~ or a
system sew~r after U5~.
With referenc~ to Fig~. 29-31, cool water from a refri-
g2ration apparatus 636 i8 directQd through a ~ain shut-o~f
valve 638, a ~ilter 640, te~peratur~ and pr~sure switches
642, 644 and to branch lin~ 648 and 650. The temperature
8witch 642 i~ interlocke~ with a ~ain huk-of~ valve for
turning off water flow in the ~ent ths cooling water temper
ature exc~eds a predeter~lned level, 3uch a3 70 degrees
fahrsnheit (21.11 degrees Cel~iu~). Thl~ shut-o~ valve is
al o closed and an alarm i~ triggored i~ the pres~ure sen~ed
by pres~ure switah 544 exceed~ a predetermined level, ~or ex-
ample, Rixty p~ig ~413,685.4 pa~cal). Water ent~ring line
6~B is directed through th~ wator ~ackets o~ the cathode as-
semblie~ 40, 42 of tha chambers 14 and 16 and then returned
via a lin~ 652 to a ~ain return line 654 and then to the
cooling apparatu~ 636.
Similarly, coollng water i~ ~ed through the water
~acket~ o~ the cathoda as~emblie3 Or chamber# 18 and 20 and
returned via a branch line 656 to the main return line 654.
~anually operatod ~hut-o~ valv~ 658 are provided ~or ~hu~-
ting o~ the water rlow a~ ~sired. The coollng water aupply
sy~tem utillzad for chambers 18 and 20 i~ ldentical to that
utilized ~or chamber 14. There~ore, the cooling 9y8tem for
chambers 18 and 20 ~ill not be de~cribed in detail.
~lZ9~4~3
56
Cooling water ~lowing along lines 648 iB directed as
shown by the arrow~ to bran~h linea 660, 662 leading to the
respective chambers 14, 16. From line 660, the cooling wat~r
is fed through lines 198 at the re~pectiYe ~ront and back
sides of chamber 14. At each ~ide of the chamb~r, water
flows through one cathode a~sembly 40, through a coupling
line 667, through another cathode assembly 40, and is re-
turned via return li~a 200 to a branch line 664. From line
664, the water flows via lines 652 and lin~ 654 to the
cooling apparatus 636. Isolation valves 666 are positioned
in the water supply lines between linQs 660 and the respec-
tive lines 198. Similar isolation valve~ 668 are interposed
b~tw~en the llnes 200 and tho return line 664. When a set of
valves 666, 668 a330ciatQd with a ~low path through a ~et of
cathodes 40 at the ~ront or rsar o~ th~ cha~ber 14 are
clo~ed, the rQspQctive ~et o~ cathode~ is i~olated ~rom the
water ~upply sy~te~ for rapair or oth~r purpose~. Also, com~
puter monitored water ~low ~w~tches 670 are positioned be-
tween the line~ 200 and 664. Ths~ switche~ enable the com-
puter to detect water ~lowing thxough tha ~ront and rear sets
of cathode as~emblies 40 and to block energi~ation o~ the
cathode assemblies in the event cooling wat~r i~ not being
delivQred to the a85emblie9.
In cha~b~r 16, cooling water ~rom th~ lin~ 662 is
directed through isolation valve~ 672 and thorugh RF matching
networks 674 to the ra~peGtivo cathode as~e~blie~ 42. The
outlet lines 200 ~rom these cathoda asse~blies pa~s through
the RF networks 674, i~olation valve 676 and water flow
switchRs 678 to a water return branch line 680. From line
680, water i~ returned to line 652 and via line 6454 to the
cooling apparatu~ G36. The pairs o~ valva~ 672, 676 operate
like the valves 666 and 668 to selectively i~olata the
cathode as~e~blies 42 ~rom thQ w~ter cooling system. In
addition, the water ~low 3witche~ 678 operate lika the
previously d~cribed ~witch~ 670.
~29~43
yacuum Pumping and Sputterinq Ga Su~ly Systems
The sputtering gas supply and vacuum pumping ~ystem
utilized in the embodiment of Fig. 1 are shown in Fig. 32.
Sputtering gas is ~upplied ~rom one or more sputtering
gas sy~tem~ ~84 to the chamber~ 14 I:hrough 20 for the sput-
tering processes. On~ ~uch sy~t~m is typically employed for
each type o~ sputtaring gas which i8 used. Argon or other
sputtering gas from a source 686 i8 ~ed through a regulator
688, pa~3t a manually controlled shu1:-off valve 690, and
through a two micron filtex 692. From filter 692, the sput-
tering gas i~ deliv~rcd via a conduit 694 through a f`low in-
dicator 696, a computer actuated sol~noid controlled valve
698, and through a needla valvQ 7û0 to the deposition chamber
14. Needle valve 700 is ad~u~ted to pro~ridel the~ appropriate
gas flow rate to the chamber. Th~a solenoid controlled valve
698 is op~ned and closed in ra~pon~e to commands from the
computer 46 to deliver ~puttaxlng gas to chamber 14 as
reguired. A conduit 702 deliver~ the sputtering ga~ from
fileter 692 to other chambers utilizing ~he ~a:~e type o~ gas.
Each such cha~ber i~ provided w~th it~ own ~low indicator,
sol~noid controllad valve and na~dl~ v~lv~.
Each o~ ths vacuum pumping ~tack~3 34 are con~tructed
from commQrcially available colaponents. Furthermore, the
pumping stack0 34 ar~ identi~al and will be described in con-
nection with ths pumping ~tack u~ed for chamber~ 12 and 14.
Each vacuum pumping stack 34 include~ a cryo co:mpressor
706 which is coupl~d to a cryo pu~p 708. The p~Llnp 708 is
coupled to a variabl~ sp~3ed orifice throttle valve 710 in
coD~Qunic:ation with a cryo trap 712. l'hs trap 712 i~
selectively coupled to the chamber 12 by a high vacuum valve
714. The ~ryo trap 712 i~ provld~d with a van~ 716.
Suitabla solenoid a¢tuatad v~lva~ 720, 722, 724 and 726 are
included in lines leading ~o tho ~y~tem ~or purposes
explained below. Howl3ver, in gen~ral, valve 720 compri~as a
cryo syatem regener~tion valve, valv~ 722 comprisss a rough
vacuum valve, val~ 724 co~prises a vacuum system purging
valve, and valve 72~; compri~e3 a chamber venting valve. In
~29~3
58
addition, a liquid nitrogen ~ill control valve 728 is also
included. Furthermore, gauges numbered as 730, 732 and 734
are provided for monitoring the vacuum sy~tem.
Th~ fir~t three chamberc 12, 14 and 16 are coupled by a
rough vacuum line 738 to a mechanical rough vacuum pumping
system 736. A ~imilar rough pumping ~ystem i~ provided for
the chamber~ 18, 20 and 22 and iE~ c:oupled to these chambers
by a rough vacuum line 739. A rough ~acu~m crossover valve
790 permits selective coupling o~ mechanical pumping systam
736, via line 739, to chambQrs 18-22 and coupling of the
other mechanical pumplng systQm, via line 738, to chambers
12-16 a~ de~ired. ~he mechanical pumping 3y8tem 736 includes
a mechanical pump 740, a comput~r controlled solenoid opera-
ted shut-o~ valv~ 742, and a bellows 744. Also, a molecular
sieve 750 i3 po~itioned in rough line 738 between the pump
740 and valves 720, 722 Or ~ach of the chambers 12, 14 and
16. A sieve heater (not ~hown) i~ provided within sieve 7~0.
A similar ~ieve and h~ater i3 provided i~ rough line 739 ~or
cha~ber~ lB, 20 and 22. In addition, pr@ssure gaugs~ 752 and
754 are provided ~or monitoring the ~tatu~ of the mechanical
rough pumping 8y8tam.
~ i~uid nitrog~n i~ suppli~d to each o~ the cryo traps
712 via a lin~ 785 ~rom a liquid nitrog~n ~upply syst~m 760.
The liquid nitrogen supply sy~tem include3 first and second
liquid nitrog~n tanks 762, 7G4, pr~sur~ relief valve~ 766,
76~, and 770, and oomputer controlled 301enoid actuated flow
valv~s 782, 784 and 786.
The gauge~ 730 monitor th~ chamber pxes6ura and include
a rough Yacuum gauge ~or monitoring the establi~hment o~ the
rough pre~ure in chamber 12. This rough vacuum gauge i~ of
the commercially avallabla type which tran~mits an eloctrical
slgnal corre3ponding to the gauge pre~sur~. Thi~ ~lectrical
signal i9 tran~mittQd to tha computer ~6 ~or monitoring of
the chamb~r pre~ure. Gauge~ 730 al~o include a high vacuum
ion gau~a ~or monitoring th3 vacuum in chamber 12 when a high
vacuum i8 being e~tabliah~d a~ explained below. In addition,
gauges 730 include ~ ther~istor gauge.
. ~
~LX91D~3
59
A ~uitable rough vacuum gauge i~ a series 275 Convec-
tron gauge manufactured by the Granville-Phillips ~ompany.
Suitable ion and thermistor gauges are Perkin-Elmer DGC~III
gauges. In addition, gaug~s 732 co~prise cryo temperature
gauges and gauges 734 may compri~e Convectron gauges. The
gauge~ 730 which monitor the chamber pressure are the same
for chambers 12, 16 and 20 except that, in chamber 16, a ca-
pacitancs monometer gauge i~ used as the rough pressure
gauge. The gauges 730 for the chambers 14 and 18 comprise
capacitance monometer gauges such a~ model 227 gauges
produced by MXS In~trument~. In addition, the gauge3 730 for
chamber 22 compri~e~ a rough vacuum Convectron gauge. Also,
although not shown in Fig. 32, the radio ~requency sputtering
chamber 16 includes a conventional hot filament for heating
the sputtering gases as required.
Each of the above gauges, like the above described
rough vacuum gauge, may be of the type which generate~ elec-
trical ~ignals corre~ponding to the para~eter being measured.
Such signals are tran~itted to and monitored by the computer
46.
The vacuum pumping system 36 u6ed in chamber 22 i like
the pumping ~yskems utilized in chambers 14, except that a
throttle valve 710, cryo trap 712, liquid nitrogen fill valve
728, and sourcQ o~ liqu~d nitrogen is not used. Because ful-
ly proce3~ed Bubstrates are received in cha~ber 22 and then
unloaded, it i8 not a~ important to establish a~ high a vac-
uum in thi~ latter chamber a~ in the other cha~bers. For
that matter, by placing the components o~ the throttle valve
in contact with the cryo pump, the cryo trap 712, liquid ni-
trogen supply, and nitrogen ~ill valve~ 728 may be eliminated
from the other chambers a~ w~ll.
The operation o~ the vacuum pumping sy~tem can be
understood with referenc~ to Fig. 32~ As~ume that a tray 270
o~ sub~trate contain~ng carrier~ 220 have ju~t been loaded in
chamber 12 and the door to this cha~ber ha~ been closed to
~eal the chamber. Also a~sume that a rough vacuum has been
established in the~ryo portion of the pumping system by the
mechanical pump 740 via valves 720 and 724. In ~his case,
1~931 ~
- 60
valve3 724 and 726 are closed. Also, the high vacuum valve
714 c108~ the path bekw~en the chamber 12 and the cryo trap
712. However, th~ rough valves 722 and roughing pump valve
742 are open~ ~ump 740 draw3 a rough vacuum ~r~m the chamber
12 via a path through valve~ 714, 722 and 742. A~ter a rough
vacuum has been established in th~ sy~tem, for example, one
millitorr (0.13 pa~cal), valve 722 i~ closed. The high vacu-
um valve 714 ia then openQd a~d th~ cryo pump 708 i~ operated
to continue the e~tablish~Qnt o~ the desir~d vacuum in cham-
ber 12.
~ iquid nitrogen ~rom ~ub-sy3tem 760 i~ delivered via
liquid nitrogen ~ill control valve 728 to the ~ryo trap 712
to assi~t in the sstabll~hm~nt o~ the high vacuum. After the
high vacuum is establish~d, it i~ maintained within chamber
12 dus to the tightly ealed natur~ o~ thi3 chamber. In
addition, becau~e the cha~ber 12 is selectiYely isolatable by
th~ ieolation valva~ ~ro~ the ad~oining chamber, a v~cuu~ may
be e~tabli~hed in thi~ ~hamber without int~r~ring with a
previously ~stablish~d vacu~ inside t~ ad~oining chamber.
It is important to e8tabli8h an extrem~ly high vacuum
in the chamber 12 prior to opening this chamber to the
adjoining chamber. For oxamplo, a vacuum on the order of 1 x
10 7 torr (1.33 x 10 5 pa~cal) may be established in chamber
12. Otharwise, it h~s b~sn ~ound that som~ conta~ination,
for example wat~r vapor ~rom ~re h ~ub~trate~ loaded ~nto
chamber 12, remain3 when the carrier0 220 are transported
into chamber 14. This water vapor can intar~ere with the
uni~ormity o~ di~c~ produced by teh proc~ss. Purging gas
~uch a~ ~iltered nitrogen, 1~ de}ivered along a llne 788
through valv~ 724 and 726 at desired timea to purge the
vacuum pumping ~ystem and al~o to eliminate the vacuum within
chamber la prior to opaning the door and loadlng o~
additional sub~tr~te~ to bc proce~ed.
In the proc~s~ing chamber~ 14 through ~0, ~ollowing the
initial e3tabli~hment o~ a hlgh vacuum in the~e chamber~, the
chambers are pres~urized ~o the de~ired pres~ure with sput-
tering ga~ ~rom ga~sy~tem 684.
,,;
61
A further understanding of the vacuum system will
be apparent from the computer logic descriptions and
algorithms set forth belowO
Computer Control System
As previous~y mentioned in connection with Fig. 1,
a programmed digital computer 46 in conjunction with
terminals 48 are used to monitor and control the system.
The computer ~6 may comprise, for example, a Hewlett
Packard Model 1000 Programmable Digital Computer. The
control software used in the computer is designed to
control the various sub-systems of the processing system
of Fig. 1, including the vacuum pumping sub-system, the
materials handling sub-system, and the sputtering sub-
system.
In the control instrumentation, the positions of
the drive shafts of the six track drive motors 626 are
monitored via the track drive encoders. The track drive
motors 626 are stepped by motor drive pulses under the
control of computer 46. The computer monitors these
drive pulses and therefrom, together with the drive
pulse count and feedback from the encoders, the position
of the transporters in the system is established.
Similar step motors 3~8 and 510 control plunger rotation
and the position of the traveling block 330 of the
loader/unloader mechanisms. Encoder feedback is also
provided for the loader and unloader drive mechanisms.
rrhus, there are twelve step motor axes which are
monitored by the computer. Each of the plunger axes,
when the optional encoder feedback system is not used,
employs a commercially available step motor controller
having an indexer and driver card. one suitable step
motor controller is available from Superior ~lectric
~b'`
~'. ~'
~'~9~3
61a
Company. The indexer produces a timed series of pulses
as required to sequence the windings of the step motor
510 and produce rotation of the motor shaft and plunger
228. ~he computer communicates with the step motor
controller, as explained below, programs the indexer
card with the desired velocity, acceleration and other
parameters, and control the operation of the indexer to
produce the
... ..
~L~9~4~3
62
desired outputs ~or step motor operation. ~he driver
card amplifies the indexer pulses to a level required to
produce a useful amount of torque at the shaft of each
of the step motors 510.
The instrumentation for controlling the chain drive
motors 626 for the transporter drive mechanisms 226, and
the loader/unloader motors 338, include an indexer card,
a driver count card, and a count compare card. Such a
count compare card is also available as a part of the
step motor controller available from Superior ~lectric.
The function of the indexer and driver cards is the same
as described above for the plunger motors 510. The
count compare card is used to count pulses transmitted
from the shaft encoders associated with each of the
chain drive motors and the loader/unloader motors. This
allows closed loop monitoring of the operation of the
step motors so that the actual motor shaft rotation, and
thus the distance traveled by the driven component, may
be verified after a move is complete.
Communication be~ween the step motor controllers
and computer 46 is through commercially available
interface cards in the step motor controllers. These
interface cards link the computer to the indexer and the
count compare cards. While a step motor is vperating,
the indexer cards generate motion busy signals which are
sensed by a da~ mLL,L ~ cont~l unit and fed
through a conventional data ac~uisition control unit
interface to the computer. The data acquisition control
unit may comprise a Hewlett-Packard Model 3497A main
frame computer which employs commercially available
function cards. Two or more such units are typically
used in the system.
, . ~
., , ~,
~29~3
62a
The data acquisition control units interface the
electrical hardware of the system of Fig. 1 to the
computer. Four different types of functions cards are
used in the data acquisition control unit. The first
type of function card is a sixteen channel digital input
card used to sense motion busy signals from the indexer
cards in the step motor controllers, and also the state
of all of the limit switches of the system o~ Fig. 1.
These digital cards produce signals corresponding to the
state of the sensed components. These
~L29~443
S3
signals are then read by the computer through the data acqui~
sition control unit.
A second type of function card i8 an eight channel high
voltage actuator card used to control solenoid~ employed in
the system of Fig. 1. E~ch card co~tain~ eight programmable
relay~. In respon~e to signals from the~e cards, ~olenoids
are operated to supply air pre~ure to control the valve
cylinder~ 30, cylinder~ 470, 506 of the plungers 228, and
other air controlled components of the system. In addition,
other components are also controlled by such actuators, in-
clud$ng the ~putteirng power supplies.
A third type o~ ~unction card utilized in the data ac-
quisition control unit i~ a twenty channel analog multiplexer
card u~ed to gate a Yalect2d analog voltagQ ~ignal into an
internal volt meter of the data acgui$itlon contrsl unit.
Each card contains twenty relays ~uitable ~or gating of low
level analog signals. The digital co~puter selects the
analog ~ignal o~ intere3t, by progra~ming a corresponding
multiplex~r relay, from the multiplexer cards. The computer
then read~ the internal voltmet~r through tha data
acquisition control unit ~nterfac~. The voltage is then
converted to a repre3entation of tho physical parameter, such
as pre3~urs, by tha computer. ~ a re~ul~, tha compu~er is
interfaced between vacuum and other physical parameter
monitoring in~truments in the ~ystem.
A flnal typ~ o~ function card i8 a dual voltage digital
to an~log outp~t card. These card~ are utilized to convert a
nu~b~r generated by the computer 46 to a correspond$rlg con-
trol volt~ge lsvel. ~ach card contain~ ~wo channels o~ digi-
tal to analog capability for gen~r~ting voltage sigrlals of
from plU3 to minus t~n vol~s, at ~i~teen milliamps. The com-
putor, vla thes~ digital to analog cards, directly controls
devicQ~ which r~quire voltage re~erence~. For example, the
output power ~rom the r~dlo ~requency generator~, used in the
radio freguency sputtering chaDber 16 in the system o~ Fig.
1, i8 controlled in this way.
;,;
~L29~3
64
Each of tha above data acquisition control units in-
cludes an internal clock which may b2 read by the computer
when the system i~ energized to establish a system time.
The vacuum gauges descri~d in Fig. 32, provide vacuum
measurements u~ed in conkrolling the operation of the vacuum
pumping sy~tem~ 34, 36. The vacuu~ gauges have analog out-
puts which intar~ace to the computer 46 indirectly through
the multiplexer cards de~cribed above. The computer monitors
the signal~, a~ ~xplained abov~, to obtain a digital repre-
sentation o~ th~ pressurQ sensed by the in~tru~ent. The in-
struments in thi~ group include the oonvectron gauges, tem-
peratur~ sensor~ and capacitance mono~eter~.
All computer control function~ ar~ implemented with
so~tware in the computer 46. Tho internal hard di~c o~ the
computer i~ u3ed for gQneral m~s ~torage of data and pro~
grams. ~n internal micro-Ploppy di~c i~ u~ed for input and
output o~ progxam~ and d~t~. In additlon, th~ te:r~inals 48
in Fig. 1 may compris~ a 8y8te~ conBole and log ~or moni-
toring the performance of thi~ ~y~tem, an operator co~mand
entry terminal, and a color graphic~ terminal for dlsplaying
the ~tatu o~ the sy~tem. A printer may be employed to pro-
duc~ hard copy outputs ~rom th~ control ~ystem.
The operation o~ th~ co~putsr 46 to control the system
o~ Fig. 1 will b2 readily appar~nt to one skilled in the art
whan con~idarad ln con~unction with th~ above tn~or~ation and
the ~ollowlng log~c d~3criptions. Ths de~cription which ~ol-
low~ explain3 the control algorlthms lmplemented to accom-
plish the ba~ic control proce~ in the ~ystem of Fig. 1.
The control proc~s~e~ ara cat~gorlz¢d according to u5e.
Materi~l~ Hand,Ling ~ te~ ontrol ProçQs~e~
o~d-Car~le~ Pxoce~s
This proce~s is u~ed to tran~er the next available
carrier 220 ~ro~ ~he planstary tray 270 to the ~inger 322 of
th~ loadar arm 320 in pr~parztion rOr tran3~rring the
carrier to the transporter ln the load chamber 12.
1) I~ a carrier a~o ~ 3 on the laoder ~ing~r 322, then skip
to st~p 8.
1~9~ 3
2) ~f the planetary tray 270 i~ empty, then terminate with
error.
3) I~ th~ first tran~porter 222 is in chamber 12, then open
the chamber 12 to 14 gate valve 28 and move the first
transportex ~ro~ cha~ber 1~ to aha~ber 14.
4) Put loader ar~ 320 ln a down po3i~ion.
~) Move the loader arm 320 to tray position of next avail~
able carrier 220 and insert ~inger 322 in hub 278.
6) Put loader ar~ 320 in up position.
7) Move loader ar~ 320 to load po~ition with carrier 220
alignQd with track.
8) Finished.
Ad~anaed~ al P~cess
Thi~ procQss i~ u~d to tran~fer a carrier fro~ a
source ch~ber to a de3tinatlon chamber, the dsstination
chamber b~ing th~ next ch~mber in th~ proc~s~. Three ~ub-
proce3~es are used $n this proc~ss and will be d~scrib~d here
be~ore the main A~anc~-Material Process.
dvanced-Material~ateri~l-to-carrier sub-~roce~3
Thi~ gUb-prOCQ~8 1~ used to move a carrisr 220 from a
plunger 2~8 to a transport~r 222 in a chamber.
Algorithm:
1) I~ trAnsporter 222 not in ch~mber, then terminate with
error.
2) If cha~ber i~ 12, or cha~ber is 22, carrier 220 is on
th~ transporter in tha cha~bsr, then skip to st~p 16.
3) I~ carrier 220 is not on the plunger 228, then terminate
with ~rror.
4) I~ plungex 1~ inserted (in rorward position in chamber),
then eklp to ~tep 9.
5) Chsck ~or op~rator rsque6ted pau~Q.
6) ~ove transportsr 2~2 to park po~ition.
7) Check ~or opQrator requ~t~d pau~.
8) Insert the plunger (move ~orwardly~.
9) Check rOr operator roquestad pau~s.
10) I~ tran~porter~not at load po~ition then ~ove it to load
position.
443
66
11) Check for operator reque~ted pause.
12) Release the plung~r grip.
13) Check for op~rator rQquested pau~e.
14) Withdraw the plunger 228 (mo~ rearwardly).
15) Check for operator reque~ted pause.
16) Finished.
Advance-Material/Material-to_Plunger ~ub-process
Thi~ sub-process i8 used to move a carrier 220 from a
transporter 222 to a plunger 228 in a chamber.
Algorithm:
1) I~ chamber i~ 12 or chamber 18 22 or carrier 220 ia on
the plunger, then ~kip to ~tep 14.
2) If tran~porter 222 is not in the cha~ber, then terminate
with error.
3) I~ carri~r 220 is not on th~ tran~port~r 222, then ter-
minate with error.
4) Check for operator r~qussted pau~e.
5) I~ plunger 228 i~ in~art~d into th~ chamber, ~hen with-
draw th~ plunger (movo r~arwardly).
6) I~ plung~r tip 232 i~ in clamping position, r~lease it.
7) Chack ~or op~rator requ~t~d pause.
8) I~ transport~r not at load poaition, then moYe transpor-
ter to load po~ition.
9) Check ~or op~rator r~que~t~d pau~e.
10) Insert plunger (mo~e ~orwardly) into hub 278.
11) Check ~or operator requ2sted pause.
12) Clamp tha plunger tip 232 onto hub 278.
13) Check ~or operator regue~ted pau~e.
14) Finished.
Ad~anc~d ~at~rl~1
Loader-materlal-to-c~rier sub~~roce9~
This sub-proce3~ i~ used to mov~ a carri~r 220 ~rom the
loader 272 to a ~ran~porter in load chamber 12.
Algorithm: ~
1) If carrier 2~ not on loader arm 320, then termina~e
with error.
~L~9~43
67
2) If loader arm 320 i9 in down posltion, then put it in up
positio~.
3) If loader ar~ 320 i~ at load posikion, then skip to step
6.
4) If transport~r 222 i~ in load chamber 12, then open
chamber 12 to cha~ber 14 valv~ and move transporter to
chamber 14.
5) Move load~r to load position.
6 ) MOVQ tran~porter to load position in cha~ber 12.
7) Put loader arm 320 ln down po~ition.
8) Move loadQr arm 320 to park position adjacent rear wall
o~ chamb~r 12.
~in Advance-Ma~rial Proce~s
Algorithm: (for main procoss)
1) I~ carrier 220 not ln ~ouxc~ ch mber, th~n t~rminat2
with ~rror.
2) I~ carri~r 220 ln de~tination cha~b~r, th~n p~us~ with
error.
3~ Repeat step 2 until caxrior 220 not in destination cham-
ber or untll proce~q is a~ort~d by op~rator.
4) Determine which tranaportQr will be u~ed to transport
the carri~r a~ follow~:
Source Cha~ber Carri~r U~ed
12
14
16 2
18 2
18 2
5) Record current ~tate o~ valve between ~ource chamber and
de~tinatio~ chamb~r ~opened or clo~ed).
6) I~ valve clo~d then open it.
7) I~ source ch~mb~r ls cha~ber 12, then exQcut~ Loader-
mat~rial-to-carri~r ~ub-proc~ or el~ ex~cute the
following two ~ub-~tep3:
7a) Move tran~por~er ~electod in ~t~p 4 to load posi-
tion in~ource chamb~r.
9~L443
7b) Exacut~ Material-to-carriQr sub-process in source
chamber.
8) Move transporter ~elected in step 4 to load position in
destination chamber.
9) Xf sourca chamber is a transporter home chamber (chamber
14 ~or fir~t transporter, cha~ber 18 for seoond
transporter, or chamber 22 ~or third transport~r) then
execute the following two ~Ub-Bt~p~:
9a) EXQCUt~ Material-to-plunger s~b-proce~s in desti-
natlon chamb~r.
9b~ Move tran portsr ~elect~d in step 4 ~o source
chamber.
10) Close the gate valvQ betw~n ~ourc~ and desitlnation
cha~b~r~.
Unload-Carrier P~ocess
This proces~ i~ u~ed to tran~er a carrisr 220 ~rom a
tran3porter to the next availabla po~it~on in the planetary
tray 270 in the unload cha~ber 22.
Algorith~:
1) If tran~porter i~ not at load poaitlon then terminate
with error.
2) If loadQr arm 320 i~ not at park po~ition in unload
cha~ber 22, then termina~ with ~rror.
3) If carri~r 220 i~ on th~ load~r arm, ~hen ~erminate with
~rror.
4) I~ carri2r 220 i3 not on the transporter, then skip to
step 13.
5) Put load~r arm 320 in down po~ition.
6) ~ove loadQr arm 320 to load posltion.
7) Put load~r arm 320 in up po~ition.
8) Move transporter to park position.
9) Ig planetary tray 270 i~ ~ull, then ~kip to step ~2.
10) MOVQ load~r arm 320 to naxt available tray position.
11) Put loader arm 320 ln down po~ition.
12) ~ov~ load~r arm 320 to park po~ition.
13) Finished.
~L~9~1L4~3
~9
SE~Ltkerinq Proces~
Proce~s-Material
This proces~ i~ used to per~orm a deposition in a
selected chamber. Several ~ub-processe^~ are used in this
process and ara dQ~cribed first be~or~ deccribing main sput-
tering proce~s. Some sub-proa~s~ mentioned below are de-
scribed abov2 in ~atQrial~ ~andling System Control Processe~.
SE ~terinc~Froaess~
Ba~ Chambex Sub-l~rocess
Thi~ sub-proco3s i3 used to bring th~ pre~sure o~ 3put-
tering gas in the chambar to the required l~v21 before igni-
ting a plasma.
Algorithm:
1) Check for operator requ~tad pau~.
2) Clo~ throt~le valve 710.
3) open proce~s gas valv~ 698.
4) Wait for proces~ ga~ stabilization tim~.
5) Walt one s~cond.
6) Read chamber pres~ura.
7~ R~paat~ ~tep~ 5 and 6 until chamber prQs~ur~ is within
process g~3 pre~surs tolerance, or until a time out
occur~.
8) I~ timed out, th~n pau~ with ~rro~ (an oporator re-
quested ratry will caus~ execu~ion o~ steps 5 through 8
again with ~nother time out interval).
9) Repeat ~t8p8 5, through 8 until the operator ha~ con-
tinued or aborted th~ proc~3 when a tim~ out occurs or
until a tlme out doe~ not occur.
~ut~q~inq P~o~e~
S~ar~S~utt~ Qnltor 5u~-~Eoaes~
Thi~ ~ub-procas~ ~tart~ a ~puttsr monitoring process,
set ~orth below, which run~ ~oncurrently with ~he ~ain sput-
tering proce~. The ~unction o~ tha ~puttar monitoring pro-
ce~s i~ to monitor ~ e depo~ition operation.
Algorithm:
~9~L4D~
1) Set handshake flag to false.
2) Start the sputter monitoring process.
3) Wait ~or handshake ~lag to be set to true ~this insures
that the sputtQr monitoring proce 8 iS running before
continuing).
SputtQr Proces~
Ram-~owe~ Sub-P:roce~
This sub-process i~ used to ra~p up the power level of
the RF power generator~ in ~ cham~er to the desired sput-
tering power.
Algorithm:
1) CalculatQ tha power increment ~or ~ront and rear power
~upplies a~ ~ollows:
front increment: ~ ~ront-powsr level/~tep~-in-ra~p
Rear-incr~ment: = rear-power-l~vol~tep~-in-r~mp.
2) Set front-accumulation and rQar-accu~ulation to O.
3) Increment front and re3r accumulation~ a~ rollow~:
front accumula~ion: o ~ront-accu~ula~ion ~ front-
incre~ent
r~ar-accumulation: ~ r~ar-accumulation + rear-increment
4) Set front and rear power level to the ~ront and rear
accumulation~.
5) Wait for ti~a-per-step.
6) Rep~at ~tsp~ 3 through 5 ~or 1 to (3tep~-in-ramp-l).
7) Set ~ront and rear pow0r level~ to the ~ront-power-level
and r~ar-powar-level (thi~ i~ tha actual regu~red power
lav~l).
Sutt~r ~rocess
$~art-powor Su~-~ro~a~
Thls sub-proces~ i~ use~ to ignite a plasma in a cham-
ber.
Algorithm:
1) I~ watsr Slow not pres~nt in target~ then pause wltherxor.
2) Close ~Ipo~er of~ relay contact~ ~or all ~pu~tering
power supplie~in the cha~ber.
~29~443
71
3) Close "power on" relay contacts for all sputtering power
upplies in the chamb~r.
4) Turn on tesla coil.
5) I~ power ~upplies are RF thQn execute the ~ollowing two
sub-staps:
5a~ Wait ~or te31a pra-ignite ti~
5b) Execute Ra~p-power Bub-proce~s .
6) S~t the pla~ma-on flag to true to indicate to the sput-
ter monitoring proca~s that depo~ition has started.
Sutter Proces~ea
stoP-Pow~r Sub-E~ocQsE~
Thl~ sub-proce~s 1~ uaed to terminata BpUttarin~ in a
chamber .
Algorith~:
1) II pow~r ~upplie~ ar~ RF then executa th~ rollowirlg ~ub-
step~:
la) Set p~wer output level o~ all supplie~ im the
chaDlber to O
lb) Wait for te~la prQ ignite time.
2) Open "powar o~f" r~lay contact~ ~or all ~puttering power
5uppl ies in ~he chamber.
3) Set the plas~a-on ~lag to ~alse to indicate to the 5pUt-
ter monitoring proc~s that the depo~ition i8 complete.
SPut~er, P~o~es~e~.
Spu~ y~ ub-~roce~s
Thi~ sub-proc~ is ueed to ~tart plung~r 228 rotating,
to iynite a plasma, and to time th~ depoaition proces3 in a
chamber.
Algorithm:
1) Execute Start-aputter-monitor 3ub-proce~.
2) Check ~or operator reque~ted pause.
3) Lock the proce~ in it~ memory partition (~or aacurate
timing o~ the deposition proces~).
4) Calculate plunyer 2~8 rotation time a~ follows:
rotation-tim~4~ proc~ time + 5 second~
lX9~L44~3
72
If the sputtering power supply i~ an RF ~upply, then add
an addltional time to the plunger rot~tion for plasma
ignition, power supply ramp up, and power 8Upply ramp
down.
rotation-time: = rotation-time + te~la-pre-ignite-time +
(steps-in-ramp * time-per-step) + tesla-post ignite-
time.
5~ Start plunger rotation.
6) Execute Start-power sub-process.
7) Walt for proce~s time.
8) Execute Stoprpow~r 3ub-process.
9) Unlock the proce~ ln it3 memory partition ~so other
proce~seR can ~hare th~ memory).
10) Clo~ the proce~ ga~ v~lve 69B.
11) Open thQ throttle valve 710.
12) Wait ~or plunger 228 to ~op rotating.
S~ut~r Proces~ea
Process-Materlal
Algorithm:
1) Check ~or op~rator reque~ted pause.
2) ~xecuts Mat~rial-to-plunger ~ub-proces~ in selected
chamb~r.
3) If a tran~port~r i~ in the chamber, move it to park
poaition.
4 ) C10~Q th~ chamber gate valve3.
5) Wait for th~ pre-depo~ition delay.
6) Check ~or op~rator requested paus.
7) Execute Back~ill-chamber sub-process.
8) Check ~or operator rQ~uested pause.
9) Execute Sputter-ln-cha~ber ~ub-proces3.
10) Ch~ck for operator reguest~d paus~
11) Wait ~or the post-depo~ition delay.
~2~4~
73
Sputter Proces~es
Sputter Monitorinq ~roce~s
Thi~ proces~ is used to ~onitor th~ deposition in the
selected chamber. It is started autv~atically by the start-
sputter-monitor BUb-prOCe~B described above.
Algorithm:
1) Set handshake flag to true to i~dicate to the deposition
process that the sputter monitoring process i~ running.
2) Wait for the plas~a-on ~lag to be set to true or until a
time out occurs. A time out will occur a~ter waiting
for the process tim~ for the depoE~ition proces~.
3) I~ time out ha~ occurred then ter~inata.
4) Wait rOr t~ala poAt-ignite time.
5) Op~n "power-on" r~l~y contacts for all ~puttering power
~upplie~ in the chamb~r.
6) Turn o~ the te la coil.
7~ Read chamber prQ~sur~.
8) Calculate 5um and ~um of sguare~ of pre~surs.
9) Wait for 1 second.
10) If no water flow in targets th~n turn off power supplies
and terminate with 2rror.
11) R~pQat step~ 9 and 10 until deposition process is over
or until ti~ to sampl~ thQ chamb~r pressure again.
12~ Repeat ~tep~ 7 through 11 until d~position process is
over~
13) Calculat~ mean and standard deviation of pressure
sample~.
Automatic De~o~ition Proc~s~as
~his proces~ i~ used to cycle a ~ingle carrier 220 ~rom
the load chamber 12, through all proc~a~ chambers 14-20, and
to th~ unload chamber 22, in an automatic mode run. ~he re-
quired number o~ r~petitions o~ this proaa~ ara invoked when
an auto~atic run i~ skarted. Many o~ ~he previously defined
sputtering proce~a~ are u~ed by this process.
Algorithm:
1) Execute Load-CRrrier process.
~9~4413
74
2) Execute Advance-Material proce~ for chamber 12, set
current chamber to cha~ber 14.
3) If proce~sing required in current chamber, then execute
the Proces~-~aterial process for the cuxrent cha~ber.
4) Execute Advance-Material proces~ for the current cham-
ber, and set the ourrent cha~ber to the next chamber.
5) Repeat steps 3 and 4 ~or current chambers of 14 through
20.
6) Execute Unload-Carri~r procss~.
Vacuu~ Pum~in~ SY~tem ~roces~es
Tha~e proces~e~ are us~d to draw a vacuum in a selected
chamber. Several ~ub-proce~se3 ar~ us8d and ~ra de~cribed
below.
Vacuum Pum;Qinq__y~e~ Proces~es
Relea~e rou~h hine~ Sub-process
~his sub-procR~Y is us~d by the maln vacuum processes
ln conjunction wlth a Get-rough lines ub-process ~o manage
and shar~ the u~e of th~ two rough pumping lines. It re-
leases ownership of any rough lin~s owned by the ~ain process
making them availabl~ ~or u~ when not usad by the main pro-
cess. It al~o control~ a rough cro~ valv~ 790 to couple the
two rough pumpo (742 and ona not ~hown ~n Fig. 32) to aither
chambers 12, 14 and 16 or cha~bsr~ 18, 20 and 22.
Algorithm:
1) I~ both rough pump3 ar0 on lins and at least one rough
line i8 owned by th~ ~ain proae~s, then close the rough
cros~ valve and skip to ~tep 3.
2) I~ a-t le~st one rough pu~p i5 on lin~ and both rough
linc~ are owned by the ~aln proce~s, then open the rough
cro~3 valvs and 3kip to ~tep 3.
3) I~ the right rough line i~ owned by ths main procos~,
then rsle~e owner~hip.
4) I~ the le~t rough line i8 ownod by th2 main process,
then rolea~e ownership.
~LX914q~3
Vac:uum Pum~n~ SYstem Proc:e~e~3
Put rouqh PumPc-on-l ine Sub-~roces~
Thi~ sub-prQce33 i~ used by the main vacuu~ processes
to put the rough pumps on line. Thi~ i3 normally re~Iuired
after a power failure.lgorithm:
oth rough pump!3 are on 1 ine then skip to 5tep 6 .
2) Attempt to obtain owner~hip of both rough lines, try for
no longsr than 1 ~econd each.
3 ) I~ ft rough pump i~ not on line AND the pressure at
the pump i~3 les~ that that required to put it on line
AND tha le~t rough line i~ owned aND (the right rough
line i3 owned OR the rough cro~s valve 1~ clol3ed) then
open the le!fk rough pump cuto~ valve.
4) ïi~ right rough pll~p if~ not on line AND the pres~ure at
th~ pump i9 le~ than that rQ~ulr~d to put it on lin~
AND l:h~3 right rough linQ i owned AND (the 1~ ft rough
line i~ own~d OR the r~ugh cro~s v21ve i~; closed) then
open the right rough pump cuto~f valv~.
5 ) E3cecutis R~leas~--rough 1~ n~ su}:\-proces~ .
6) Fini~hed.
Vacuu~ PuEp~n~ SY~te~ Proce~e~
Pu~p-rou~h ~ina-~o~n Sub-~roc~s~
Thi~ ~ub-proG~s~ i~ used to veri~y that the spe~ified
rough lina can be pumped to th~ prQs~ure required by the main
v~cuum processes for u~e o~ the rough line. It assumes that
th2 rough pump to be u~ed 1~ on line.
Algorith~:
1) Walt ~or the rough line pre~ure to reach th~ proper
prQ~sure. ~ima out a~ter the rough lin~ time ou~ value.
2) I~ step 1 timed out, then exeauta the ~ollowing sub-
!3te~pB:
2a) Clo~e the rough pum~ valv~
2b) Pau~e with error
~9~4~3
76
2c) If a retry i~ requasted by the op~rator, then open
the rough pump valve and ~xecute steps 1 and 2
again with a new time out int~rval.
3) Repeat step~ 1 and 2 until step 1 doe~ not time out or
until the proce~s is continued or abort~d by the
operator.
vacuum ~ ~in~ Syst~m Proce~se~
Ge~ouah Line~ Sub-roc~s~
This sub proce~s is used by the ]~ain processes in con-
junction with the RelQa~e-rough line~ ~ub-proces~ to manage
and sh~re tho use o~ th~ two rough lin~s. It ~btains owner-
ship o~ th~ ~peci~iod rough lina and al~o the other rough
linQ i~ it i8 reguirod by tha main vacuu~ process. It veri-
fies that th2 rough line3 can b~ p~p~d down. It handle~ the
case when on}y on~ rough pump i~ o~ }in~ by opening the rough
cross~valva.
Algorithm-
1) Ex~cu~e Put-rough pu~p~-on-llne ~ub proce~s.
2) If both rough pu~p~ ~r~ on lin~ th~n execut~ steps 3
through g el~ ~kip to 8t~p 10.
3~ Obtain owner~hip o~ th~ rough line.
4) Close all cha~ber rou~h and cryo reg~nerats valv~s ~or
ths rough lin~.
5) Clo~e ths rough cros~ valve.
6) Executo Pump-rough linQ-down sub-proces~ ~or the rough
line.
7) I~ th~ other rough line 1~ raquired by the main vacuum
proces~, then attempt to obtain ownership of the other
rough line, but only try ~or 10 ~acond~.
~) Ir owner~hip i~ obtained in ~t~p 7, then ex~3cute the
rollowing sub-~tep~:
8a) Close all chAmber roug~ an~ cryo regen~rate valves
~or the other rough lln~
~b) Ex~aute Pump-rough llna-down ~ub-pro~2s~ ~or th~
other rough lin~
8c) Open th~ ~ough cros~ valve.
9) Skip to ~tep 15~
9~
10 ) I f no rough pUmp8 are on 1 ine then termina~e with error.
11) Obtain ownership of both rough lines.
12) Close all chamber rough and cryo regenerate valves ~or
both rough line~.
13) Open the rough cross valve.
14 ) ~xecute pump-rough line-down ~ub-proc~ss for the rough
line. This ha~ the effect of pumping both rough lines
with one rough pump since only o~e pump is on line but
the rough cro~s valve i~ open).
15) Finished.
Vacuum P~pin~ Svste~ P~oce~es
Hi~h VacUum Sub-P~ocess
This sub~proce6~ i~ u~ed to put ~ chamber o~ the ~ystem
into a high vacuum modQ. A rough-cha~bar sub-proce~s i5 uged
in thi~ main High Vacuum Sub-proc~s. It i documented here
before the ~ain process.
Vacuu~ PumpLng_~yg~_m Proce6se~
Hiah Vacuu~ Sub-Process
Rou~h-Cha~ber Sub-Process
This ~ub-pr3cas~ is u~ed to rough a chamber to a lower
cros~over pressure. Th~ cros~ov~r pre~ure i~ at a pre~eter-
mined level (i.e. ona hundred microns) where the rough vacuum
has been e~tablishad to a low enough level ~or the high vacu-
um to be drawn by the high vacuum portions o~ the vacuu~ 5ys-
tems.
Algorithm-
1) I~ chamb~r pre~sure l~s~ than or equal to lower cross-
over pres~ure, than ~ip to step 10.
2) Execute Get-rough llne~ ~ub-proc~s~.
3) C10~Q tha as~ociaked cha~ber gate valve~ 28, proces~ gas
valve 698, vent valve 726, rough valve 722, and high
vacuum valve 710.
4 ) Check ~or oparator requested paus2 .
5) open chamber rough valve 722.
6~ Wait for chamb4r pre~sure to reach lower cro~30ver pres-
aure, ~ait no long~r than th~3 chamber rough tim~ out.
~29~43~
7) Clo~e chamber rough valve 722.
8) If timed out then pause with error (an operator reques-
ted retry will cau3e steps 5 thro-lgh 8 to be executed
again wi~h a new ~lme out value).
9) Repeat ~tepB 5 throuyh 8 until no time out or until
operator has continued or abortsd the process.
10) Finished.
Vacuum Pumplna Sy~tem Proce~ses
Hiqh-Vacuum Sub-Pxoc:e 9
Algorithm:
1) I~ high-vacuum valve 710 is opened then skip to ~tep 10.
2) Check for operator re~ue~ted pau~a.
3) Cl03e the chambar g~te valva~.
4) Chec~ for operator reque~ted pause.
5) Execut~ Rough-chamber ~ub-proc~Q.
6) Wait for cro~sov~r d~lay.
7) Read chambar pre~ur~.
8) Repeat 8tQp~ 4 through 7 until cha~ber pre~sure is less
than tha upp~r crossover pra~ur~, or until the number
of allowed itera~ion~ ha~ b~en ~xhaustad.
9) ExecutQ Relaase-rough lin~3 ~ub-proces~.
10~ I~ chambQr pre3~ure not le~e than uppQr crossover pres-
sure, then pau30 with orror ~an operator reguasted retry
will cau~6 ~tep~ 4 through 10 to b~ executed again with
a ~et o~ iteration~).
11) Rep~at step~ 4 through 10 unt$1 chamber pres~ure is less
than uppQr cro~ov~r pres~ure, or until process has been
continued or aborted by the operator.
12 ) ChQck ~or operator r~quasted ~au3e.
13) Close th~ as~ociated chamber isolation valve~, process
ga~, vent, rough and high-vacuum valve~.
14) open the chamber hlgh-va~uum valve 710.
Vent Proc~
Thi~ proce~s ~ used to vent a chamber o~ thQ 3ystem to
atmosph~ric pra~ ure.
~X~ 3
79
Algorithm.
1) Close the chamber isolation valves, process gas,
vent, rough and high-vacuum valves.
2) Check for operator requested pause
3) Open the chamber vent valve 726
4) Wait for vent time.
5) Close chamber vent valve.
Vacuum Pumpin~ System Processes
Rou~h and Chill Cry~o Pump Process
This process is used to rough and chill a cryo
pump. It is used by the Regeneration and Recover
pxocesses. Several sub-processes are used only in this
process. There are documented before the main process.
Algorithm:
1) If cryo pressure is less than or equal to lower
cryo crossover pressure, then skip to step 12.
2) Isolate the cryo pump frnm the rest of the vacuum
pumping system.
3) Execute Get-rough lines sub-process.
4) Check for OperatQr requested pause.
5) Turn cryo compressor off.
6) Set bakeout complete flag(s) to false indicating
that the molecular sieve(s) for the rough line(s)
is being used and will reguire(s) baking out.
7) Open the cryo regenerate valve 720.
8) Wait for cryo pressure to reach the lower cryo
crossover pressure, but wait no longer than the
rough cryo time out valve.
9) Close the cryo regenerate valve 720.
10) If step 8 timed out, then pause with error (an
operator re~uested retry will cause steps 7 through
10 to be executed again with a new time out
interval).
11) Repeat steps 7 through 10 until the cryo pressure
is less than the lower cryo crossover pressure, or
until the operator continues or aborts the process.
12) Finished.
. . .
~2~3~4~3
Vacuum Pumpi~ Svstem Proce~es
Rouqh and Chill Cryo_~Pum~ rocess
Chill-cryQ_Sub-proces~
This ~ub-proc~s~ is ~s~d to chill a cryo pump to a de-
sired chill ~ndpoint temp~ratur~.
Algorithm:
1) If cryo te~peratur~ i~ lesY than or equal to the chillcryo endpoint temperature, then turn cryo compressor on
and ~kip to stQp 7.
2) Check ~or operator requ~ted pau~e.
3) Turn cryo co~pres~or on.
4) Wait ~or cryo temperature to reach chill cryo endpoint
temperature, but wait no longer ~han the chill cryo tima
out.
5) If ~top 4 tim~ out, th~n exQGut~ the ~ollowl~g sub-
step~:
5a) Turn cryo compr~3~0r of~
5b~ Pau~e wlth error (an op~rator retry w~ll cause
~ep~ 3 throuqh 5 to be Qx~cuted again with a ne.w
time out int2rval).
6) Repeat stsps 3 throu~h 5 until cryo temp~rature i3 less
than or sgual to the ch~ll cryo endpoint t~mpsrature, or
until oparator continua~ or ~borts the prOCe~8.
7) Finished.
~L~cuu~ nplnq SY~ 2roc2s3e~
Rouqh_an~ ChiLl Crvo Pum~ Process (Main Process)
Algorithm: :
1) Check ~or operator r~qu~ted pau~.
2) Execut~ the rough-cryo sub-proce~3.
3) Wait ~or cryo cro~ov~r delay.
4~ Read cryo pra~ur~.
5) Repeat ~tep~ 2 through 4 un~il cryo preesure i~ le~s
than uppar cryo ¢ro~80ver pres~ura, or until the maximum
allowed it~ra~ions have been ~xecut~d.
6) ExecutQ the R~a~e-rough line~ ~ub-procQ~e.
~29~L443
81
7) I~ cryo pressure i3 greater than the uppar cryo cross-
over pra3sure, then pau~e with error (an operator re-
quested retry will cause steps 2 through 7 to execute
again with a naw set of iterations).
8) Repeat ~tep~ 2 through 7 until cryo pressure is less
than the upper crcss-ov~r pr~s~ure, or until operator
has continued or aborted the proces~.
9) Ex~cute Chill-cryo sub-proce~.
Vacuum Pumpin~ Syst~m ~^oceasQs
Si~ve-Bakeout Proae~s
Thi~ proce~ us~d to bak~ out one or both the
molecular ~ieve traps 750 o~ th~ roughing pump ~y~tem.
Algorithm:
1) Execute Get-rough lines ~ub-proces~.
2~ If the bakeout-complete ~lag ~or the rough lin~ i~ true,
then skip to ~tep 11.
3) Determine if both ~i~va~ are to be bakad out. Both
~ieve~ are to b~ b~ked out if both rough line3 are owned
by the main process.
4) Turn on the siev~ heat~r for th~ rough linQ.
5) If both ~ia~e~ ar~ to be baked out, then turn on the
sievQ h~ater for the rough l$ne.
6) Wait for the bakeout delay tim~.
7) Execut~ Pump-rough lina-down ~ub-proces~.
8) Turn of~ th~ sieve he~ter ~or the rough line.
9) Set th~ bak~out-complete ~lag ~sr the rough line to
true, indicating that thQ ~i~v~ for the rough line has
been baked out.
10) I~ both ~iev~ wara baked out, then ~xecute the
~ollowing 9ub-step~:
lOa) Turn of~ the ~i~ve ha~t~r for the other rough llne
lOb) Set the bakeout-complete fla~ ~or the other rough
line to true.1) Execute Releaae-rough llne~ ~ub-process.
~g~ 3
~ .
Vacuum Pum~in ~ ~tem Proces~es
Re~eneration Proce~s
Thi~ proces~ i~ used to regenerate a cryo pump of the
system. Several ~ub-proce~sas are u~ed in this regeneration
prcces~ and are described first.
Vacuum~ umDlnq~ Svs.tem ProceYs
Reganer~tion Proces~
Start-bak~out Sub-proces~
This ~ub-proce~ initiate~ the ~i.ave bakeout process.
Algorithm:
1) Start the ~i~ve-bakeout proce~3.
Vacuum Pumnina Sv~t~m ~roce~s
R ~enera~ion ~rocess
PuroLe-and-warm-cryo Sub-~oces~
Thi~ purge-and warm ~ub-procs~ i3 u~ed to bring the
cryo pump to room temperature. ~h~ cryo pu~p i5 purged for
an additional time after thi~ t~p~rature i8 achieve.
Algorit~m:
1) ExecutQ Start-sieve -bakaout sub-proc~
2) Clo~ the high-vacuum, purge and regenerate valve~ for
the cryo pumping apparatu~.
3) Check ~or op~ra~or equaated pau~e.
4) Turn oryo compr~s~or of~.
5) Open cryo purge valv~.
6) Wait ~or tha cryo to roaoh roo~ temp~rature, or for
purge time out whichever ia ~ir~t.
7) I~ ti~2d out, then pau~e with ~rror (an operator re-
quested ret~y will cau~e 8t9pB 6 and 7 to be executed
again ~ith a new timQ out valu~).
8) Repea~ ~tep~ ~ and 7 until room te~psrature i~ reached
or until the operator ha~ continued or aborte~ ~he pro-
C~
9) Ch~ck ~or op~rator r~guestsd p~U~Q.
10) Wait ~or the additional purge ti~e.Check ~or op~htor reque~t~d pau-Q.
.. .
-~
~''3~4~3
83
12) Wait for bakeout-complete flag to be set to true, but
wait no longer than the bakeout delay plus the rough
line time out (this flag indicates that the sieve bake-
out started in step 1 is complete).
13) Check ~or operator rsqu~ted pause.
14) Close cryo purg~ valve.
15) If timed out in Bt~p 12 then ter~inate.
vacuum Pumpln System Process
Reqeneration Proce~s fMa~n Process)
Algorithm:
1) Generate operator mas~age to turn the cold trap ~ill
controller 728 o~.
2) Record ~tate o~ high-v~cuum valve 710 (opened or
clo~ed).
3) C10B~ the high va~uum valv~ 710, purge valve 724, and
regeneration v~lves 720 ~or the cry.
4) Check ~or opeartor requested pau~e.
5) ~xecute Purge-and warm cryo 3ub-proce3~.
6) Ch~ck for op~rator regue tad pau~e.
7) Execute rough and chill cryo pump proce~.
8) Check ~or operator r~que~ted pau~s.
9) I~ recorded state o~ high-vacuu~ valve i~ opened, then
execute tho high vacuum, sub-prooe~.
Vaouum ~ ein~ s~ste~ Proce~
Recov~ Proces~
Thi~ proce~s i~ used to recover the cryo pump3 a~ter a
power failure. Thi~ process is auto~atically started afker a
power ~ailur~.
Algorithm:
1) Determin~ 1~ regenoration i~ allowed.
2) Executa Put rough pu~ps-on-line ~ub-process.
3) Read cryo te~peratur~ ~nd pre~sure.
4) I~ cryo temperature i~ les~ than or equal to the chill
cryo endpoin~ temperature OR cryo pressure is less than
or aqual to ~e low~r cryo cros~over pressur2, then
43
84
start the rough and chill cryo pump proces~ for the cur-
rent chamber and ~kip to step 6.
5) If regneration is allowed, then start th~ regeneration
proce ~ for the current cha~berJ or else log a message
lndicating th~ cryo ne~d~ to b~ rege~erated.
6) Repeat ~tep~ 3 through 5 for cha~bers 12 through 220
operation o~ thQ Fir3t Embodiment
Substrates, ~uch a~ el~ctrole~s nickel plated aluminum
substrate~, are fir~t suitably cleaned prior to processing.
For example, the 8ub3trat~ may be sprayed with 1,1,1 tri-
chloroothane which ha~ been dis~illed and ~lltered through a
10 micron filter. This remov~s the majority of the polishing
abrasiv~ and r~si~ua ~rom the substrata~. Substrates are
then ultrasonically clsan~d in a dzgr~a~er bath containing
1,1,1 trlchloroe~han~ haated ~o 159~162~Cal~iua (C~ and fil-
tered to 10 micron~. ~he ~ubstrate~ are rai ~d through the
v~por zon ab~va thi~ ~ath. Th~n, th~ aub~trates are lowered
into a second bath containing 1,1,1 trichloro~than~ heated to
159-162C and filtared to 10 mlcron~ and again ultrasonical-
ly c~eanad. The sub~tr~t~ ar~ ral~ad through the vapor zone
abo~e thi~ bath and low~r0d into 3tlll ano~her bath contain-
inq 1,1,1 trichloro~thane, which has b~en distilled ~rom a
boiling ~ump at 159-162C. Fro~ thi~ last bath the sub-
strates are rai~ed into th~ vapor zone, allowod to drain, and
then 810wly rai~ed at ~ 310w rata to clear tha vapor zone.
Thes~ lattar 3t~ps ~liminata ~vaporation marks ~ro~n the sub-
strate ~ur~acas. ~h~ cleaned ~ubstrates are ~tored in an en-
closed box. Additional cleaning ~ay b~ p~rformsd a~ needed.
A~t~r loading of ~ tray o~ Aubstrata~ lnto chamber 12
~in a cloan roo~), a vacuum i~ e~tablish~d in chamber 12.
Also, a vacuum i~ establi3h~d in cha~ber~ 14 through 22 as
well. In addition, cathode a89e~bli~ 40, 42 may be pre-
sputt~red to bring tha~o cathode a~0embl i9~ to a ~teady state
operation.
The load~r 272 in chamber 12 ~hen picks up the flrst of
the carrl~r~ 220 ~r~m the tray and po~ition~ it in th~ center
of the track in cha~ber 12. A transporter 222 then enters
~9~43
chamber 12 and is loaded with the carrier. The loaded
transporter then travels to chamber 14, wherein the
plunger 228 in this chamber is inserted into the hub 278
of the planetary carrier and grips and lifts the
planetary from the transporter. The transporter is then
shifted out of the way of the sputtering cathode
assemblies 40 in chamber 14. The plunger 278 then
rotates the planetary carrier 220 and supported
substrates and sputtering of a first layer (for example,
of chrome) is performed. Following sputtering, the
transporter 222 in chamber 14 transfers planetary
carrier 220 to chamber 16 and then returns to chamber 12
to fetch another carrier for chamber 14. A second
transporter delivers substrates processed in chamber 16
to chamber 18 and also delivers substrates processed in
chamber 18 to chamber 20. In this way, successive
chrome, cobalt-platinum, chrome and carbon layers are
sputtered onto the substrates. Finally, a third
transporter transfers the processed substrates from
chamber 20 to chamber 22. The planetary carrier 220 is
unloaded from this third transporter by an unloader
mechanism 272 and placed onto a tray 270. In this
manner, the processing continues.
After the last planetary carrier 220 is lifted from
the tray in chamber 12 and delivered to chamber 14, the
vacuum in chamber 12 is relieved and the door 68 to this
chamber is opened. The next tray of substrates is then
loaded. Chamber 14 is isolated form chamber 12 during
this loading operation. After the desired vacuum is
reestablished in chamber 12, a first transporter from
chamber 14 is returned to chamber 12 to obtain the first
planetary carrier 220 from this new tray.
In a similar manner, after the tray in chamber 22
is filled, chambers 20 and 22 are isolated and chamber
22 is opened to permit replacement of the filled tray
. .
. ~ , . ...
~lZg~43
85a
with an empty tray. The vacuum is then reestablished
in chamber 22. Thereafter, carriers are again
transferred between chambers 20 and 22.
The isolation valves in housing 26 permit the
isolation of the chambers from one another so that the
parameters affecting sputtering may be optimized in each
of these chambers. In addition, the processing speed is
enhanced because
,
'.J., ,, ~<
~91~4~
86
processing may continue while additional trays o~ substrate
containing planetarie~ are load~d and unloaded from the re-
~pective chamber~ 12 and 22.
Pre~errQd Embodimant of ~i~. 33
Another embodim~nt of tha inventio~ is sho~n in Fig.
33. This embodiment lncludes cha~ber~ 12, 14, 16, 20 and 22
like those hown in the embodim~nt o* Fig. 1. In addition,
isolation valve~ are al~o provlded for ~lectiv~ly i~olating
these chamber~ from one another.
As can ba se~n from Fig. 33, this sQcond embodiment of
the invention eli~inate~ tha proce~sing chamber 1~. There
~ore, during processing, the carri~r~ 220 are transrerred in
the ~ollowing ~e~uQnce through the cha~ber~ o~ thi~ e~bodi-
ment. From load chamber 12, a carrier 220 i~ delivered to
chamber 14 for sputtQrlng o~ th~ und~rlayer onto the 9ub-
~trate~. From cha~bQr 14, thQ carrier 220 i3 trans~erred to
chamber 16 Por depo~ition of ~he ~econd la~er. From chamber
16, rather than trav~lling to a chamb~r 18, the carrier 220
is return~d to chamber 14 for depo ition of the third layer.
In thi~ ca~e, both the ~ir~t and third d~po~ited lay~rs are
of the same material, such a~ chrome. The sputtering, po~er
and other param2t~r~ are ad~u~ted in chambex 14 to ad~ust the
deposition o~ thi~ th~rd layer. ~or ~xample, to make the
third layer thinner than the ~irst layer. From chamber 14,
the ~ub~trate~, now cont~ining thrae d~pos$ted layero, are
trans~erred to chamb~r 20 ~or d~po~ition o~ the ~ourth layer.
Finally, fro~ cha~ber 20, the carrier~ are delivex~d to the
unload chamber 220
A single transport~r 222 may be utilized to per~orm
thi~ sequenc~. How~ver, three tran~portera are pre~erred, as
in the ca~e o~ th~ Fig. 1 embodiment. ~h3 ~ir~t o~ these
trans~oxters travel~ ~rom chamber 12 to chambar 14. The
~econd Or the~e tran~porter~ travel~ b~twen cha~b~r~ 14, 16
and 20. Finally, the third Or ~hese ~ran~porter~ travels be-
tween chambar3 20 and 22.
The ~mbodimefl~ o~ Fig. 33 is ~lightly ~lower t~lan the
embodiment o~ Fig. 1, becau~e o~ the ~act that the cha~ber 14
87
is utilizQd for two d~poRitions. Nevertheless, this embodi-
ment illustrate~ the principle that the system does not re-
quire transportation o~ the carriers 220 in on~ dîrection
from ona end of the ~ystem to another.
Pre~erred Embodiment o~ Fi~. 34
Still another embodimant o~ the invention ic shown in
Fig. 34. This embodim~nt i~ like the embodiment o~ Flg. 1,
except that th~ load cha~ber 12 ha~ b~en modified to include
a pair of load chamber~ 12a, 12b like the previously de-
~cribed chamb~r 12. In addition, an inter~ace chamber 12c is
also employ~d. Th~ inter~ace chamb~r 12c i8 position2d be-
tween the load chamber~ 12a, 12b ancl th~ fir~t processing
ahamber 14.
Also, in tha e~bodiment four transport~r~ 222 are
utilized. A ~ir~t tr~n3port~r trav~l~ between the cha~bers
12a a~d 12c on a track 224~ loacted at the rear of chamber
12c. A ~cond transportar trav01s betwaen chambers 12b, 12c
and 14. The third transport~r travQls betwe~n chambers 14,
16 and 18. Finally, th~ ~ourth tran~porter travels between
cha~ber~ 18, 2 0, and 22.
In th~3 Fig. 1 ~ystem~ ~ub~tantial tim i~ required to
e3tablish a vacuu~ in cha~ber 12 to a desirsd high vacuum
l~vel be~or~ tr~n~ar~ betwQen chambsrs 12 and 14 ar~ psrmit-
t2d. In ~om~ cas~, a delay in proc~inq occur~ becau~e
ch~mber 14 i~ empty ~or a p~rlod o~ time until the de~ired
vacuum ia ostabliahad in cha~b~r 12, and carrier~ 220 ar~
again transferr~d fro~ chamb~r 12 to chamber 14. The embodi-
men~ of Fig. 34 eli~ina~s any ~u~h d~}ay.
: Specl~ically, a tray 270 o~ carrier~ 220 i po itioned
in chamber 12a and al~o in chamber 12b. A vacuum is esta-
blished ln theaa chamb2rs. Th~ carriers 220 are loaded ~rom
one o~ th~ chamb~ra, ~or exa~ple chamber 12b, onto a tran~-
porter which carriaa th~ carrier~ through the lnterrace cham-
ber 12c and to tha chamb~r 14 ~or procassing as proviously
explainad. When ahamber 12b is empti~d of carriers,
proces~ing con~inu~ by uaing carriar~ ~rom chamber 12a.
That i~, the rsar tran~por~er 2~2 obtains a carrier from
'
~9~443
88
chamber 12a and carries it to interface chamber 12c. The
plunger 228, which may be like those previou~ly described, is
then utilized to pick the planetary toward the front cha~ber
12c and load~ it onto a transporter. ~hi~ latter transporter
carries the carrier to hamb~r 14 to continue the substrate
processing. While carriar~ are being tran~ferred from
chambar 12a, a n~u tray iA place~ in chamber 12b and a vacuum
is reestablished in this chamber. Thereafter, when chamber
12a i emptied of it~ carriers, the ~y~tem then utilizes
carriers fro~ the replenishQd chamber 12b. Also, while the
carrier~ are u~ed ~rom chamber 12b, a new batch o~ carriers
is loaded into chamber 12a. Thu~, in tha embodiment of Fig.
34, alternately operating load chamber~ are pro~ided for
delivering a continuous supply o~ carriers to downstr~am
chamber~ ~or procassing.
Also, th~ unload chamber may comprise two unload cham-
bers, like the load chamb~rA 12a and 12b, togethQr wikh an
unload inter~ace chamber like 12c. However, this is not
typically used. That i8, unifor~ity in the ~rocessed discs
is particularly af~ected by contaminants, such as water
vapor, carried by unproces~ed sub~trates from chamber 12 to
cha~ber 14. ~y pumping chamber 12 to a high vacuum, such
effectR ar~ ~inlmizad. How~v~r, the disc~ are far less
sensitive after they h~vo be~n completoly processed.
Consequently, di~a6 may bo trans~errQ~ ~rom chamber 20 to
chamber 22 wi~hout waiting ~or th~ establi~hment of a vacuum
which i~ a~ high a~ the vacu~m in chamb~r 12.
In addition, ~putt~r ~tching ~or ~leaning purpose~ may
be perfor~ed in chamb4r~ 12 and inter~ac~ chamber 12c a~ de-
sired~ To accompli~h sputter Qtching, ~puttering a semblies
and a plungar i8 utilized in the3~ ¢ha~bers. Sputter ~tching
i~ accompli~hed by n~tive}y biasing the plunger 228, and
thus the carrier which i~ mounted to thQ plunger and th~ ~up-
port~d ~ub~trat~. q'hi~ cau9~ po~ltive ions in the plasma
to bombard the ~u~trate~ and remov~ a ~mall quanti~y of ma-
terial ~rom the sub~trats ~ur~ace~. Substantially uniform
etching occur~ bea~s~ the plan~t~ry ~otion ~mparted to the
substrat~s during ~tching expossA both substrate sur~ace3 to
1~9144~3
8~
the pla~ma~ Al~o, additional procea~ing apparatus 790 may be
placed in chamber~ 12 or 12c. Such apparakus ~ay comprise
commercially availabls ion gun~ which bo~bard tho ubstrates
with ion~ ~or cl~aning purposes. Altarnately, or in addi-
tion, such apparatu~ 790 may compris~ ~ub~trate heaters for
warming the ubstrates prior to delivary to chamber 14.
Having illu~trated and dQscribQd thQ principla~ of our
invention with refQrence to ~averal pr~ferred embodiment3, it
should be apparQnt to tho~ persons skillad in the art that
such invention may b~ modi~i~d in arrangement and d~tail
without departing from such principl~. We claim as our in-
vention all such modi~ication~ as co~ within the trua spirit
and ~cope o~ the ~ollowing cl~ims.
