Note: Descriptions are shown in the official language in which they were submitted.
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HEAD ASSEMBLY FOR ROTATING STORAGE DEVICE
~ackqround of the Invention
This invention relates to sliders on which
heads are mounted for accessing information stored on a
rotating medium.
A magnetic disk, for example, is typically read
from and written on by a magnetic head, held on a
movable arm near the surface of the disk. The head is
mounted on the rear or trailing edge of a slider,
downstream with respect to disk rotation, as part of a
head assembly supported by the arm. The head assembly
also includes a suspension system and electronic
circuitry to connect the head via the arm to the disk
drive electronics. Electrical connection from the end
of the arm to the head is usually made by a pair of
twisted wires welded to the head's terminal pads on the
rear edge of the slider. The wires are dressed to form
a service loop between the arm and the head. The head
and slider do not actually ride on the surface of the
rotating disk but instead fly over the disk surface on
an air boundary layer created by the rotation of the
disk. The slider and suspension are carefully designed
to achieve the desired flight characteristics, and the
service loop between the arm and the head is arranged to
have minimal influence on the suspension/slider
mechanical system.
Summary of the Invention
The invention features a slider with the
conducting terminals for the head mounted on the largest
surface of the slider that is not the surface closest to
the rotating medium; or on a surface of the slider
parallel to the surface closest to the rotating medium;
or the terminals and the head are mounted on different
surfaces of the slider.
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In another aspect, the suspension elements ~which have a
fixed conflguratlon definlng predetermlned mechanical
characteristics to control the movement of the slider) also
functlon as the conductlve paths between the arm and conductlve
terminals that are located on the slider and are connected to the
head.
Another general feature of the lnvention ls a method of
maklng multiple sllders ln a batch process by deposltlng multiple
copies of the head ln an array of rows and columns on one surface
of a block of materlal, sllclng the block into bars along one
dlmension, deposlting multlple copies of the conductlve terminals
for the head on a surface of the bar ad~acent to the surface on
which the head is deposlted, whereln the conductlve paths between
the head and the conductlve termlnals wrap over a corner between
the ad~acent surfaces, and sllclng the bar lnto lndlvidual
sllders.
Preferred embodlments of the lnventlon lnclude the
followlng features. Two thln film heads are posltloned on the
rear edge of the slider. Thln fllm conductlng clrcultry connects
the head on the rear edge of the sllder wlth termlnal pads on the
upper surface of the sllder. The head termlnal pads are dlrectly
connected, wlthout wlres, to the suspenslon clrcultry elements of
the head assembly system and thus to the dlsk drlve electronlcs.
Connectlng the head termlnal pads dlrectly to the
termlnal polnts of the suspenslon clrcult ellmlnates the need for
a wlre cable servlce loop and, therefore, ellmlnates any
mechanlcal lnfluence on the sllder's lntended fllght
characterlstlcs. Placlng the head termlnal pads on the large
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2a 60412-1948
upper surface of the slider enables the sllder to accommodate a
larger number of connectlons per head, and allows the overall
slider slze to be reduced.
In summary, a flrst broad aspect of the lnventlon
provldes a slider bearlng a head for accesslng lnformatlon on a
rotatlng rnedium and conductlve termlnals for sald head, sald
conductlve termlnals belng mounted on the largest surface of sald
sllder that ls not the surface closest to sald rotatlng medlum.
Accordlng to a second broad aspect, the lnventlon
provldes a sllder bearlng a head for accesslng lnformatlon on a
rotatlng medlum and conductlve termlnals for sald head, sald
conductlve termlnals belng mounted on a surface of sald sllder
parallel to the surface closest to sald rotatlng medlum.
Accordlng to a thlrd broad aspect, the lnventlon
provldes a sllder bearlng a head for accesslng lnformatlon on a
rotating medlum and conductlve termlnals for sald head, said
conductlve termlnals belng mounted on a surface of sald sllder
dlfferent from the surface on whlch sald head ls mounted.
Accordlng to a fourth broad aspect, the lnventlon
provldes a method of maklng a sllder of the kind bearlng a head
for accesslng lnformatlon on a rotatlng medium and conductlve
termlnals for said head, said method comprlsing depositing
multlple coples of sald head ln an array of rows and columns on
one surface of a block of materlal, sllclng sald block lnto bars
along one dlmenslon, depositing multlple coples of sald conductlve
termlnals on a surface of sald bar ad~acent to the surface on
whlch sald head ls deposlted, whereln conductlve paths between
sald head and sald conductlve termlnals wrap over a corner between
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2b 6041~-1948
said ad~acent surfaces, and slicing sald bar into lndivldual sald
sllders.
According to a fifth broad aspect, the lnventlon
provldes apparatus for supportlng, on an arm, a head for accesslng
lnformatlon on a rotatlng medium, sald apparatus comprlslng a
sllder bearlng (1) sald head ln a positlon for accesslng sald
lnformatlon, and (11) conductlve termlnals electrlcally connected
to sald head, and suspenslon elements supportlng said sllder on
sald arm, sald suspenslon elements havlng a fixed conflguratlon
deflnlng predetermlned mechanlcal characterlstlcs to enable sald
sllder to assume a desired orlentatlon relatlve to sald rotating
medium, and sald suspenslon elements provldlng conductlve paths
from sald termlnals to sald arm.
Accordlng to a slxth broad aspect, the inventlon
provldes a sllder bearlng a head for accesslng lnformatlon on a
rotating medlum, comprlslng a rear edge on whlch sald head ls
mounted, a rear face perpendlcular to sald rear edge and bearlng
electrlcal termlnals for connectlon to a suspenslon element for
supportlng sald sllder, and contlnuous conductlve paths leadlng
from sald head on sald rear edge to sald termlnals on sald rear
face.
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Other features and advantages of the invention
will be apparent from the following description of the
preferred embodiment and from the claims.
Description of the Preferred Embodiment
We first briefly describe the drawings.
Fig. l is an exploded isometric view, not to
scale, of a portion of a slider suspension system.
Fig. 2 is an isometric view, cut away, not to
scale, of a slider attached to other sliders in t~e
final stage of slider fabrication.
Fig. 3 is an isometric view, cut away, not to
scale, of a block of slider substrate material at the
first stage in the slider fabrication process.
Structure
Referring to Fig. 1, a movable arm 10 supports,
near a magnetic disk 12, a head assembly 20 which
includes a suspension circuit 30, a slider 40 attached
to the suspension circuit 30, and two thin film heads 50
with appropriate conducting circuitry s2 formed on the
slider 40.
The suspension circuit 30, chemically etched or
stamped from an electrically conducting material, such
as beryllium-copper, is 0.378" x 0.346". It is composed
of a set of fingers 36 which are organized in generally
concentric tiers. These fingers form a spring
suspension for slider 40. The conducting fingers end at
terminal points 38 and ground 39, which are welded to
the head's eight terminal pads 54 and the common ground
terminal pad 56, on the rear (upper) surface 42 of the
slider 40. The opposite ends of the conducting fingers
are welded at eight terminals 32 to corresponding
circuitry on arm 10. Although Fig. l shows the
suspension 30 generally in a single plane, for clarity,
it is preferred to bend the fingers to form a recess to
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receive the slider in order that the center of gravity of the
slider lie on the main plane of the suspension.
The fingers of the suspension circuit 30 thus both (i)
provide direct electrical connections from the thin film heads 5d
via conducting circuitry 52 on the movable arm (not shown) that
lead to the disk drive electronics and (ii) have a fixed,
carefully designed configuration which defines predetermined
mechanical characteristics to enable the slider and suspension
system to have desired flight characteristics relative to the
magnetic disk.
The slider 40 (Fig. 2) is made of alsimag (which is
somewhat conductive) and has a width 43 of 0.126", a length 44 of
0.158", and a thickness 45 of 0.034". Two thin film magnetic
heads 50 are deposited on the rear edge 46 of the slider and
connected by thin film conductors 52, which extend up over the
corner 48 and onto the rear (upper) surface 42 of the slider, to
terminal pads 54 located on the rear surface. The thin film
conductive paths 52 are 0. 005" wide and 2 microns thick with a
minimum of 0. 005" separation between each path. Conductive paths
52 terminate at eight terminal pads 54, four for each head, each
terminal pad being 0.020" X 0.015" x 0.0005". An additional
conductor from each head terminates in a common ground terminal
pad 56 ( 0 . 050" X 0 . 050" X 0 . 0005" ) . The positioning of the
conductive paths and the terminal pads is symmetrical and
corresponds to the positioning of the terminal points on the
suspension circuitry. An encapsulating layer of alumina 60 as an
electrical insulator surrounds
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the thin film heads and the conductive paths, and
underlays the terminal pads, leaving only the top
surfaces of the terminal pads exposed.
Prior to the attachment of the suspension
circuit to the slider, the thin film heads are tested,
and the better one is designated the head to be
activated. The suspension circuit is oriented as it is
attached to the slider so that the ground terminal pad
39 will also contact two of the terminals (shown as 55
in Fig. 1) from the head that is not to be activated,
thus shorting out that head.
Manufacture
The slider is manufactured by batch
processing. In general, in the first stage, multiple
copies of two thin film heads for the rear edges of the
sliders are laid down on a block of material in an array
of rows and columns. The block is then sliced into bars
on which multiple copies of the conductive paths, or
thin film circuitry, and conductive terminals for the
rear face of the slider are deposited in rows. The
conductive paths between the thin film heads and the
conductive terminals wrap over a corner between adjacent
bar faces. The bars are then sliced into individual
sliders for final finishing.
More specifically, referring to Fig. 3, a block
41 of alsimag is polished to produce an extremely flat
and smooth surface 61. Next a thin film of alumina 62
is sputtered over the entire surface 61. Each head 50,
including its conducting circuitry 52, is then
constructed by depositing thin films of different
materials on this prepared surface 61. These films are
patterned using photoresist techniques; the structure is
laminate in form. The conductors of a slider are
patterned to reach the edge 63 of the intended rear face
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of the slider. Another insulating film of alumina 64 is
then sputtered over the entire surface, and the block is
sliced into bars, along edges such as 63, each bar
having a thickness approximately equal to the thickness
of the slider.
Referring again to Fig. 2, the rear face of
each bar 42, including the exposed ends 53 of the
conductor elements 52 that were deposited on the rear
edge of the slider, is also polished to produce an
extremely flat and smooth surface finish. The ends of
the conductors 53 are masked while a thin film of
alumina 66 is sputtered over the remaining unmasked
surface. The ends of the conductors are then unmasked,
and the required thickness of copper to form the
remainder of the head conductors 5~ (on the rear face)
is sputtered over this prepared surface. A two-axis
programmable stage laser is used to remove the copper
coating between the elements of the intended circuit
pattern. The registration of the pattern must ensure
that the start of each conductor element on the rear
face of the slider coincides with the corresponding
conductor end on the edge of the bar 48. This will form
the electri.cal interconnect. A final insulating layer
of alumina 60 is sputtered over the surface leaving
exposed only the terminal pads and ground which are then
plated with copper to the desired additional thickness.
Conventional manufacturing procedures are followed to
create an air bearing surface, including rails 72, on
the front face of each bar 70. The bar is sliced into
individual sliders along edges such as 49 to complete
the batch manufacturing process.
Referring again to Fig. 1, the heads are tested
to determine the one to be activated and the terminal
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points 38 and ground 39 of the suspension circuit 30 are
welded directly to the terminal pads 54 and the common
ground terminal pad 56 on the slider 40 in nine places,
shorting out the head that is not to be activated.
Other embodiments are within the following
claims.
