Note: Descriptions are shown in the official language in which they were submitted.
~Z~ 5
-- 2 --
BACKGROUND OF THE INVE~TION
Field of the Invention
This invention relates to a novel photopolymer-
izable laminate. More particularly, the present invention
pertains to a photopolymerizable laminate which is useful
for preparation of a printed circuit board.
Description of the Prior Art
As pho~oresist materials for preparation of
printed circuit boards, photopolymerizable elements, so-
called dry film resists, which comprise a photopolymer-
izable layer and a support layer have been known. The
dry film resists are usually prepared by laminating a
photopolymerizable material on a flexible support film,
and optionally covering the surface of the photopolymer-
izable material with a protective film. When preparing
a printed circuit board by use of the dry film resist
(hereinafter referred to as "DFR"), first after peel-of
of the protective layer, the photopolymerizable layer is
laminated on a substrate for forming permanent images,
for example, a copper-clad laminate and then subjected
to imagewise exposure, followed by peel-off of the sup-
port layer, if desired. Subsequently, by using a develop-
in~ liquid, the support layer left to remain as desired
and the unexposed portion of the photopolymerizable layer
are removed by dissolution of dispersion to form a resist
image on the surface of the substrate. Then, a desired
printed circuit board can be obtained by two ways. One
way consists of etching the portion of the substrate
where the resist is not formed and stripping the resist.
The other way consists of plating the portion of the
substrate where the resist is not formed, stripping the
resist, and etching the substrate where the resist has
been stripped.
, . ...... .
.
- - , . ~ .
~L,f6~8~5
Whereas, recently, among the printed circuit
boards prepared by use of DFR, increased is the printed
circuit boards with electrical connection between one
surace and the other surface of the boards through an
electroconductive circuit~-forming material layer, for
example, a thin copper layer, provided on the inner sur-
faces of thru-holes. As the method for preparation of
pxinted circuit of this kind, the copper thru-hole methods
and the solder thru-hole methods are generally known, and
the tenting method is becoming popular among the copper
thru-hole methods. In the tenting method, simultaneously
with formation of wiring images by exposure, both open-
ings of the thru-hole are completely sealed with the
photo-hardened layer. During etching of the copper thin
layer~ etc., in order to orm a wiring, said pho~o-
hardened layer protects the electroconductive layer on
the inner surface of the thru-hole agains-t etching solu-
tion and therefore it is possible to obtain a printed
circuit in which the both surface are conductive to each
other through the thru-hole. The electroconductive
circuit-forming material layer on the peripheral surface
o the openings of the thru-hole may have a width which
is very limited due to the restriction in circuit de~ign-
ing. Accordingly, Inthe above-mentioned tenting method,
the photopolymerized layer sealing the openings on both
sides of the thru-hole is supported on a band portion
with a very narrow width which is called land. The ex-
posed photopolymerized layer sealing the openings will
be showered with developing solution and etching solution
and therefore may frequently suffer from breaking of the
photopolymerized layer or peeling o*f from the substrate.
For this reason, the photopolymerizable layer to be used
for the tenting method is required to have good mechanical
strength, good adhesiveness to the substrate and chemical
resistance after exposure.
~Z'~ )5
In this context, the pho-topolymerizable layer
of DFR widely used a-t present time comprises (1) an un-
saturated compound having at least one ethylenic group
capable of photopolymeriza~ion as a monomer, (2) a thermo-
plastic organic polymer as a binder, (3) a photopolymer-
ization initiator and (4) other additives (see U.S. Patents
3,6~2,33~ and 4,320,189).
The above-mentioned monomer may include tri-
methylolpropane triacrylate and pentaerythritol triacrylate
having two or more ethylenic double bonds. As another
e~ample, there is also shown triethyleneglycol diacrylate
having ether linkage. On the other hand, as the binder,
those compatible with monomer are chosen, as e~emplified
by polymethyl methacrylate, copolymers of methacrylic
acid es~er, acrylic acid ester or styrene.
However, the mechanical strength or the adhesive-
ness with a substrate o~ the photopolymerized layer is
influenced by the monomer, the binder and their ratios
employed, particularly greatly by the monomer. The
mechanical strength, chemical resistance and adhesiveness
with the substrate of the photopolymerizable layer em-
ploying the monomer as mentioned above are not necessarily
satisfactory, when the photopolymerizable layer is thin.
Accordingly, when using the tenting method, the photo-
polymerizable layer must be made thick.
On the other hand, demand for minituarization
of electronic parts and elements is increasingly strong,
and correspondingly the printed circuit board with higher
density or finer lines is strongly desired.
For formation of such a high density printed
circuit, the DFR e~loyed must have a high resolution,
but the resolution is lowered by increasing the thickness
of the photopolymerizable la~er. Accordingly, when image
:
5 ~z~
~ormation i9 ef~ec~ed by applying the DFR comprising the
photopolymerizable layer as described above for the tent-
ing method, it is di~ficult to obtain a circuit image
which is very precise and o~ high density.
On the other hand, according to the solder thru-
hole method widely used also at the present time, the
electroconductive circuit-constituting material layer,
~or example, copper thin layer, is covered with a protec-
tive m~tal such as solder before etching of the unnecessary
portions on the surface of the substrate for forming
permanent images. In the solder thru-hole method, the
substrate covered with a patterned photopolymerized layer
is subjected to cleaning for copper plating such as
defatting by alkali washing, defatting by washing with an
aqueous surfactant solution or electrolytic polishing,
and then to electroless copper plating and further to
copper plating and solder plating. Accordingly, also
in the case of preparin~ a high density printed circuit,
a line distance o~ the circuit will become narrower.
Thus, when the line distance becomes narrower,
penetration of a plating solution or a cleaning solution
into the resist or bet~een the resist and the substrate
and small 10at of the resist during cleaning:.before ::
pl~ting,:copper.plating:and:solder:.plating treatmènt
pose great problems, and therefore DFR is required to
have excellent resistance to cleaning reagents, copper
plating and solder plating. The copper plating resistance,
solder plating resistance and resistance to cleaning re-
agents of the photopolymerized layer are also influenced
by the monomer and the binder employed for the photo-
polymerizable layer, particularly predominantly by the
monomer and its amount. The photopolymerizable layer
using as the monomer an acrylic acid ester or a meth-
acrylic acid ester having only an ester bond or an ester
bond and an ether bond such as trimethylolpropane tri-
,
., `
~Z'~ 5
-- 6 --
acrylate or polyethylene glycol diacrylate is insufficientparticularly in copper plating resistance, solder plating
resistance and resistance to pre-treatment chemicals.
In order to compensate for such drawbacks, for
example, it has been proposed to add a heterocyclic com-
pound to the photopolymerizable layer (see U.S. Patent
3,622,334 and ~apanese Laid-open Patent Publication No.
192946/1982). However, such composition has a dis-
advantage that the additive may sometimes be precipita~ed
during storage of DFR for a long term.
G.B. Patent 1379228 discloses a photopolymer-
izable copying material using a monomer represented by
the formula (A') shown below:
R~ Rl
R3'C-~ ~12 ) n;~ CO-NH-X-NH- C~O- ( CH2- ~1 2-O) m- ~2- C-R2 1 (A l )
R9
wherein X'is a saturated hydrocarbon radical with 2 to 12
carbon atoms or an arylene radical with 6 to 10 carbon
atoms,
Rl and Rl ~ ~ which are identical or different, are each
alkyl with 1 to 3 carbon atoms, R4 or CH2R4 ~
R2, R2', R'3' and R3' are identical or different and are
each H, CH3 or CH2R4,
R4 iS O--CO~Rs = CH2,
Rs iS H or CH 3, and
nland m~are identical or different numbers from 0 to 20,
R4 being present in at least one of the radicals ~l, R2
and R3 and in at least one of the radicals Rl', R2 ' and
R3
However, the monomer represented by the formula (A') is
small in solubility in a conventional developer for manu-
facturing of printed circuit boards using DFR, such as
, ..
:
~8~
l,l,l~trifluoroethane, trichloroethylene, etc. This
means that minute amount of monomer will remain on the
substrate, even when attempted to remove the unexposed
portion by developing, which poses the problem that
subsequent steps of plating, etching, etc. will not
proceed uniformly.
As the improved method ~or preparation of a
printed circuit board using DFR, it has bee-n proposed
to use a photopolymerizable laminate whose support layer
can be dissolved or dispersed in a liquid for developing
of the photopolymerizable layer and, after exposure for
image formation, to remove by developing the flexible
support layer and the unexposed portion of the photo-
polymerizable layer as such, wi~hout peeling off the
~lexible suppoxt layer from the photopolymerizable layer,
thereby forming a resist image on a substrate for forming
permanent images (U.S. Patents 4,211,560, 4,301,230 and
4,360,582). This method has the advantage of simplifying
the steps in preparation of printed circuit boards.
However, in the case when using as the monomer
in the photopolymerizable layer in this method, for
example, an acrylic acid ester or a methacrylic acid ester
having only an ester bond or an ester bond and an etner
bond such as trimethylolpropane triacrylate or poly-
ethylene glycol diacrylate, if lamination is performed
at a high temperature while applying an excessive tension
on DFR, there may be ~enerated cracks on the flexible sup-
port layer laminated on the substrate for forming perma-
nent images.
SUMMARY OF THE INVENTION
-
The principal object of this invention is to
provide a photopolymerizable laminate which results in
images having good mechanical strength and excellent
~ .~ ~
'
~ ' ,
,
plating resistance after exposure.
Other objects and advantages of the present
invention will become apparent from the following descrip-
tion.
The laminate disclosed in the pre~en~ inven-
tion comprises a photopolymerizable laminate comprising
a photopolymerizable layer and a support layex, optionally
with a protecti~e layer existing on the surface of the
photopolymerizable layer, said photopolymerizable layer
containing:
tl) S to 95 ~ by weight, based on the total weight
of the photopolymerizable layer, of a binder comprising
a vinyl polymer or a vinyl copolymer,
(2) 95 to 5 % by weight, based on the total
weight of the photopolymerizable layer, of a monomeric
component containing at least 50 % by weight of at least
one compound selected from the group consisting of the
photopolymerizable unsaturated compounds represented by
the formulae (A), (B) and (C) shown below and having
a value of molecular weight/number of double bonds con-
tained of 1000 or less, and
(3) 0.01 to 30 % by weight, ba~ed on the total
weight of the photopolymerizable layer~ of a photopolymer-
ization initiator,
O H H O
Il I r 1 1 11
CH2=C-C-O-X-C-O-C-NH-Y-NH-C~Z-CI-NH-Y-NH-C~C-X-o-C-C-CUz (A)
R, R2 O O O R2 R~
O H
[CH2=C-C-~X-l-O-C- ~ (B)
11
Rl R2 O m
O U H O
[CH2-C-C-O-X- C-O-C-~W-NEl- C-O-~-C-NH-~NH-C-O-C-X-O-C-C=CH2 ] ( C )
Rl R2 1 Rz Rl m-l
.... .
wherein
_ is an inteyer of 0 or more;
m is an integer of 3 to 10;
Rl is hydrogen or methyl;
X is a divalent Cl-a aliphatic hydrocarbon group,
~CH2-CH-0 ~CH2- or ~CH2t-0-C ~ C-~CH2tr(where R3is aCI_4
R9 0 0
alkyl group, _ is an integer of 1 to 10, $ and r are each
an integer of 1 to 4);
R2 is a Cl-6 alkyl group or CH2-O-R4 (where R4 is phenyl,
an aryl group or a Cl_6 alkyl group);
Y is a divalent C2_l~ hydrocarbon group;
Z is ~CH2 ~ 0- , ~CH2-lCH-OtX
R
CIH3
-CH 2 -C-CH 2-- or -CH-CH 2--Zl- CH 2-CH-0-
. I
CHg CH2-0-C-C=CH2 CH2-0-C-C=CH2
Il ~1 11 1
0 Rl 0 Rl
(where t is an integer of 2 to 10, x is an integer of 1
to 30, Z is tCH2 ~0- , ~CH2-CH-Otx ,
CH3 Rl
-CH2-C-CH2-0- , -C ~ -C-0- or
CH3 0 0
CH3
-CH2-CH-0 ~ C ~ 0-CH-CH2-0- ); and
Rl CH3 R
W is ~Y-WI l~p~-
Y o /C-N\
[where Wl is -NH-C-N C-NH- , -N\ /C=0 ,
I ~-N
O O
11
-NH-C-0-W2-0-C-NH- or
0-C-NH-
o
s
- 10 --
~ C~ ~ H2 ~ ~
(W2 is a trivalent C3_l0 alkyl group)].
DETAILED DESCRIPTION OF THE INVENTION
As the binder, thermoplastic polymers comprising
polymers or copolymers of vinyl monomers may be used.
Among them, polymers or copolymers comprising monomers
of the formula (D) are preferred:
~VI
H2C = C \ (D)
wherein Vl represents hydrogen or methyl and V2 represents
phenyl, -~ORs, -O-~-CH 3, Cl or vinyl (Rs is hydrogen or
an alkyl group having 1 to 10 carbon atoms).
It is more preferable to use a polymer or a co-
polymer comprising a monomer selected from methyl meth-
acrylate, methyl acrylate, butyl acrylate, methacrylic
acid, acrylic acid, styrene and butadiene.
The molecular weight of the binder may prefer-
ably be 20,000 to 500,000, more preferably 50,000 to
300,000, in terms of we.ight average molecular weight.
If the molecular weight is too large, developing time
will be undesirably prolonged~ On the contrary, a binder
with too small molecular weight will lower disadvantageously
the mechanical strength of the cured resist.
The photopolymerizable unsaturated compound
to he used in the pre~ent invention is required to have
a value of its molecular weight divided by the number
of double bonds which is not more than 1000, preferably
from 100 to 700. The photopolymerlzable unsaturated
:.
.;
~, .
: ` ''. ' ~ .
1Z~L~I 88~)5
compound is selected from those having the formula (~,
(B) or (C) as specified above, ~ut a comhination of
plural kinds o~ photopolymerizable unsaturated compounds
may also be used. To describe about the formula (A),
the upper limit of n is determined spontaneously depend-
ing on the molecular weight per double bond of the com-
pound. Rl may preferably be hydrogen from standpoint of
polymerizability. X may preferably be ~CH2tk wherein k
is an integer of 1 to 6, ~C~I2-CH-O~ OEI2- wherein p is
CH3 P
an integer of 1 to 10, or -CH2-CH2-O-~ C-O-CH2- ,
particularly -CH2-. As R2, an alkyl group having 1 to 4
carbon atoms are preferred. More preferably, methyl and
ethyl may be employed. Y should preferably be selected
from the groups as set forth below:
ÇH3 ÇH3
~CH2~ , -CH2-C,-CH2-CH2-CH-CH2- ,
CH3 CH3
- -CH2 ~ CH2- and
CH3 C'13
(s is an integer of 2 to 8).
Among them, hexamethylene group, 2,2,5-trimethylhexa-
methylene group and toluylene group are further preferred.
Z may preferably be tCH2ttO- or ~CH2-~lI-Otx (where t is an
integer of 2 to 10 and x is an integer of 1 to 30). The
values of t and x are also spontaneously limited by
limitation of the molecular weight of the compound.
As Rl, methyl is preferred here.
In the formula (B), W is ~Y-~p-Y- and Wl may
preferably be one selected from the following structures
~ '
- 12 -
(El) to (E4~:
~ o
-NH- -N-C-NH- (El)
C -N~ (E2)
C -N\
-NE- -O ~2-O-~-NH- (E3)
O-~-NH-
~ ~I2 ~ CH2 ~ (E4)
wherein W2 is a trivalent alkyl group having 3 to 10
carbon atoms and _ is an integer of 3 to 10~
Among them, a compound wherein Wl has the structure (El),
Y is hexamethylene or wherein Wl has the structure (E3),
W2 is represented by the structure (Es) and Y is hexa-
methylene or toluylene is particularly preferred:
CH2-
CHg-l-CH2- (Es)
CH2-
Of the formulae (A) r (B) and (C), those re-
presented by the formula (A) are preferred as the photo-
polymerizable unsaturated compound, and a mixture of the
compounds with n being from O to 2 or 3 is preferred.
Next, an example of the method for preparation
of these compounds i5 briefly descrihed. Among the com-
pounds represented by the formula (A~, the compound of
n=O can be obtained from the reaction between a starting
monomer represented by the formula (Fl) and a diisocyanate
represented by the formula (F2):
, ~ :
;; ..........
. ,
- 13 -
O H
CH2=l-C-o-X-I-OH (Fl)
Rl R2
OCN-Y-NCO (F2)
If a diol represented by the (F3) i9 further permitted
here to be co-present with the above monomers, compounds
represented by the formula (A) of n=l or more will be
formed, simultaneou~ly with formation of the compound
o n=0:
HO-Z-H (F 3 )
Further, the compound represented by the formula
(B) is the reaction product between a monomer represented
by the formula (Fl) and a polyisocyanate represented by
e formula tF4):
W t NCO )m (F4)
Here, if a diol represented by the formula ~F 3) iS permit-
ted to coexist, the compound represented by the formula
(C) will also be formed. In the above formulae, Rl, R2, X,
Y, Z, W and m have the same meanings as definPd above.
Preferable examples of the monomer (Fl) may
include ?-hydroxypropyl acrylate, 2-hydroxypropyl meth-
acrylate, 2-hydroxybutyl acrylate, 2-hydroxy-3-phenoxy-
propyl acrylate, polypropyleneglycol monoacrylate,
polypropyleneglycol monomethacrylate, acryloxyethyl-2-
hydroxypropyl phthalate, methacryloxyethyl-2-hydroxy-
propyl phthalate and the like.
Preferable examples of the diisocyanate (F 2)
may include hexamethylene diisocyanate, toluylene di-
isocyanate, 4,4'-diphenylmethane diisocyanate, xylylene
diisocyanate, isophorone dilsocyanate, 2,2,5-trimethyl-
, ~ - : -
'' ~ "
~zL~
- 14 -
hexamethylene diisocyanate and the like.
Typical examples of the diol (F 3 ) are ethylene
glycol, propylene glycol, butane diol, hexane diol, and
further diols represented by the formula (Fs):
HO-IH~CH2-O-Zl-CH2-CH-OH
CH2-O-~ cH2 CH2-O- ~ CH2 (Fs)
wherein Rl is hydrogen or methyl, and Zl is preferably
~CH2~-0- or ~cH2-cH-otxl (t' and x' is each an
integer of 1 to 10).
Typical examples of the polyisocyanate (F 4 )
are water adducts of hexamethylene diisocyanate, iso-
phorone diisocyanate and toluylene diisocyanate, re-
spectively, and trimethylol propane adduct.
The reaction should desirably be conducted
in a sol~ent. As the solvent, aromatic hydrocarbons
such as toluene or xylene, esters such as ethyl acetate,
butyl propionate, ketones such as acetone, methyl ethyl
ketone or methyl isobutyl ketone are preferred. While
the reaction can proceed under either absence or presence
of a catalyst, it is preferred to use a catalyst in order
to carry out the reaction rapidly. As the catalyst,
there may be employed, for example, a tertiary amine
such as triethylamine or triethylene diamine, or a
organo tin compound such as stannous octoate or dibutyltin
dilaurate.
It is alsu desirable to carry out the reaction
under the conditions where the carbon-carbon double bonds
in the compound (Fl) or (Fs) will not be polymerized.
For this purpose, the reaction temperature should be
,
,, . . . -i, - ~
,.
, ~
.- : . :
15 -
80 C or lower, preferably 50 C or lower. The reaction
is also desired to be conducted, while shielding the
reaction system from light.
Further, it is preferable to react one equiva-
lent or more of hydroxyl groups per one equivalent of
isocyanate group to avoid free isocyanate groups.
The monomeric component in the photopolymer-
izable layer in the present invention may also contain
other photopolymerizable compounds, if desired, provided
such compounds are not main components in the monomexic
component.
Such photopolymerizable compounds may include
monomers represented by the following formulae;
H\ Z2
/C = C / (F6)
H \Z3
wherein Z2 is hydrogen, methyl or halogen and Z 3 iS phenyl,
vinyl phenyl, cyano, halogen, pyridyl, imidazolyl or
-CO-O-Z 4 (wherein Z 4 iS C 1-1 2 alkyl group, C6_l0 cyclo-
al~yl group, allyl, benzyl, C2_6 hydroxyalkyl group,
C 3- 8 dialkylaminoalkyl group, C~-6 halo alkyl group,
tetrahydrofurfuryl, halo phenyl, carbitol group or
hydrogen), and including, for example, styrene; divinyl-
benæene; acrylonitrile; methacrylonitrile; monoacrylates
such as ethyl acrylate, isopropyl acrylate, butyl acrylate,
cyclohexyl acrylate, ben~yl acrylate, 2-ethylhexyl acrylate,
lauryl acrylate, carbitol acrylate, methoxypolyethylene
glycol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl
acrylate, 2-hydroxy-3-chloropropyl acrylate, 1,4-butylene-
glycol monoacrylate, dimethylaminoethyl acrylate, di-
ethylaminoethyl acrylate, tetrahydrofurfuryl acrylate,
2-chloroethyl acrylate, 2,3-dibromopropyl acrylate,
tribromophenyl acrylate, allyl acrylate, ~-chloroacrylo-
. ~ .
,, .
: -
8~Q5
- 16 -
nitxile, vinyl pyridine, vinyl imidazole and so on;
CH2 = f-C-O-Zs-O-I-C = CH2 (F7)
RlO O Rl
wherein Zs is C2_ 1 o divalent alkyl group or
H-CH2-O ~ H-CH2~ (wherein Q is an integer of 1 to 20
Rl Rl
and Rl is hydrogen or methyl) and Rl is the same as de-
fined above, and including, for example, acrylic ac.id
esters or methacrylic acid esters of diols such as pentane
diol, hexane diol, ethylene glycol, tetraethylene glycol,
nonaethylene glycol, polyethylene glycol, neopentane
diol, polypropylene glycol and the like;
O O Rl
Il 11 1
CH2 = f-C-O-Z6-O-C-C = CH2 (F~)
Rl o-C-f=CH2
Rl
.
wherein Z 6 iS C 3 _ 1 2 trivalent alkyl group, C 6 - 1 4 tri-
valent alkoxyalkyl group or
-C-C-N~ _N--C-o and Rl is the same as defined above,
and including, for example, trimethylolpropane, tri-
acrylate, tri(acryloxypropoxy)hexane, tri(acryloxypropoxy)-
propane, tris(hydroxyethyl)triazine acrylate and meth-
acrylic acid esters corresponding to these;
IZ7 l12
fH2 fH2
Z8-CH2-f - -CH2-O-CH2-f - -CH2-ZlI ~Fs)
Zg Zlo i-
1 1
wherein at least three o Z7 - Zl 2 are -O-C-C-CH2 (wherein
O
.
:,
'
- 17 -
Rl is hydrogen or methyl) and the remaining are hydroxyl
groups and i is 0 or 1, and including, for example,
pentaerythritol triacrylate, pentaerythritol tetraacrylate,
dipentaerythritol hexaacrylate, dipentaerythritol penta-
acrylate, dipentaerythritol tetraacrylate and dipenta-
erythritol triacrylate;
R, l2H5 C2H5 R~
C=C~ 0_~2_l-~2-~lCl-Zl3-lCl~0-~2-l-C~2-O-lCl-C=~2 (Flo)
o IH2 o o CH2
o l
C=o Cl-o
RL_C=CH2 R~-C=CH2
wherein Z13 iS Cl-8 divalent alkyl group, ~ or
~ , Rl is the same as defined above and ] is an
integer of 2 to 6, and including, for example, ARONIX
(product of Toa Gosei Kagaku Kogyo.`.Kabushiki Kaisha);
IRl H
3 ( F 1 1 )
wherein Zl 4 iS C 1- 1~ alkyl group, Cl- 6 hydroxyalkyl group
1 1
or -CH2-NH-C-C=CH2 and Rl is the same as defined above,
and including, for example, acrylamide, methylenebis-
acrylamide, N-t-butylacrylamide, N-t-octylacrylamide, N-
methylolacrylamide, N-butoxymethylacrylamide and methacryl-
amides corresponding to these;
~ Rl
/CH2-N-~~C=CH 2
CH2=C,-~-N~ ,CH2 (F12)
Rl 2 N~C_C=CH2
~1
. *trade mark
.
' ~
- 18 -
wherein Rl is the same as defined above;
~ CH=CH-I-OZl5 (Fl3)
wherein Z 15 iS hydrogen or Cl_lO alkyl group, and includ-
ing, for e~ample, cinnamic acid, ethyl cinnamate and
propyl cinnamate;
HC,C ~
Hll N-Z 16 (Fl4)
wherein Z 16 is hydrogen, phenyl or
~ CH~ ~ W\ ¦¦ , and including, or example,
maleimide, phenyl maleimide and diphenylmethane bis-
maleimide;
diacrylates or dimethacrylates represented by the follow-
ing formula (Fls)~ R1
CH2=C-C-O-CH2- IH_CH2_0_Zl_CH2_ 1 -CH2-O- ICl-C-CH2 (F 1 s )
R, O OH OH O
wherein Rl and Z1 are the same as defined above; and
diacrylates or dimethylacrylates represented by the
following formula (Fl 6 )
CHg Rl
CH~ CI~O-Z 1 e~CH2~ CH 9 0~ CH2-Z 18-~ ICl-C=CH2 ( F 1 6 )
wherein Zl 8 iS -CH2-~ -CH- or -~H2-C- , Rl is the same
~H3 ~H
- : .
:, :-
` :, .' ~ ' " : '
' ''; . ~ ' :
.. ~ ~. ,
- 19 - ~2~
as defined above and n is an integer of 1 to 4.
Examples of photopolymerization initiators or
pho~osensitizers available in the present invention may
include, for example, polynucleus quinones such as benzoin,
benzoin alkyl ethers, anthraquinone and the like; dyes and
electron-donating substances such as benzophenone, chloro-
benzophenone, Michler~s ]cetone, fluorenone, thioxanthone,
dialkylthioxanthone, halogenated thioxanthone, isoamyl
dimethylaminobenzoate, ethyl dimethylaminobenzoate,
naphthalene sulfonyl chloride, azobisisobutyronitrile,
l-azobis-l-cyclohexanecarbonitrile, 2,4-dichlorobenæoyl
peroxide, diphenyl disulfide, dibenzothiazole, 1-(4-
isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 2-
hydroxy-2-methyl-1-phenylpropane-1-one, erythroycin and
the like; triethylamine, p-aminobenzoic acid esters, tri-
phenylphosphine, 2,2-dimethoxy-2-phenylacetophenone, and
so on. These photopolymerization initiators or photo-
sensitizers may be used either individually or as a
combination of two or more compounds.
~ he weight percentages of the components based
on the total weight of the polymerizable layer are 5 to
95 %, preferably 20 to 80 %, more preferably 30 to 70 %
for the ~inder: 95 to 5 %, preferably 80 to 20 ~, more
preerably 70 to 30 ~, for the monomeric component; and
the monomeric component contains at least 50 % by weight
of at least one compound selected from the group consist-
ing of the compounds represented by the formulae (A), (B)
and (C~. The content of the photopolymerization initiator
may be 0.01 to 30 %, preferably 0.1 to 15 %, more prefer-
ably 1 to 10 %.
Further, in the photopolymexizable layer of the
present invention, it is possible to add additives such
as dyes, stabilizers, copper surface adherents, plasti-
cizers, et~.
The photopolymerizable layer may have a thickness
which may differ depending on the purpose of use, but may
preferably be 5 to 150 ~m, more preferably 5 to 70 ~m, for
use in preparation of a printed circuit board, with resolu-
tion being enhanced as the thickness in thinner.
The support layer to be used in the photopolymer-
izable laminate of the present invention may be either
transparent or opaque to active rays, but desirably trans-
parent transmissive of active rays in view of the working
operations in the image forming step.
As the support layer transmissive of active rays,
there may be included films of polyethyleneterephthalate,
polyvinyl alcohol, polyvinyl chloride, vinyl chloride co-
polymer, polyvinylidene chloride, vinylidene chloride co-
polymer, polymethyl methacrylate, methyl methacrylate co-
polymer, polystyrene, styrene copolymer, polyamide and
cellulose derivatives.
As already described above, the process, in
which resist images are formed by subjecting both of the
support layer and the photopolymerizable layer as such
without peeling the support layer off from the photo-
polymerizable layer to developing for removal of the
unexposed portions, has the advantages of simplification
of the process and stability of images. To be applied
for this process, the support layer is required to be a
material which can be dissolved or dispersed in a solvent
which dissolve or disperse the photopolymerizable layer.
As the support layer, it is particularly preferred to use
a film of polymethyl methacrylate, methyl methacrylate
copol~mer, polystyrene or styrene copolymer with respect
to its solubility when the liquid ~or developing is an
organic solvent, or to use a polymeric film containing
amino groups, ammonium groups, hydroxyl groups, carboxylic
groups or salts thereof, such as polyvinyl alcohol film~
..
.
- 21 -
cellulos~ derivative film, when the liquid for developing
is aqueous.
The protective layer may exist on the surface
of the photopolymerizable layer, and must be easily peeled
off from the photopolymerizable layer. For this purpose,
polyethylene film, polypropylene film, Cellophanel peeling
paper or polyethyleneterephthalate treated with peeling
agent is preferably used as the protective film.
~ he photopolymerlzable layer disclosed in the
present invention can be hardened by irradiation of active
rays, and the active rays herein mentioned refers to
visible light, UV-ray and electron beam. As the light
source, there are the sun, arc lamp, mercury lamp, high
pressure mercury lamp, ultra-high pressure mercury lamp,
sterili~ing lamp, xenon lamp and fluorescent lamp.
The photopolymerizable laminate disclosed in
the present invention is particularly useful for use in
ormatlon of printed circuit board. In both of the cases
o~ the copper thru-hole process according to the tenting
method and the solder thru-hole process, the present
photopolymerizable laminate can be used in conventional
manner widely known in the art to prepare print wiring
plates with very good results. In the tenting method,
as reflected by the high mechanical strength of the
hardened film and good adhesion to the substrate, there
is little damage on the sealing film for thru-hole during
developing or etching. On the other hand, in the solder
thru-hole method, during plating, good plating resistance
was exhibited without any plating solution penetrated
into the surface between the resist and the substrate.
Also, since the unexposed portion can be completely re-
moved by developing, etching or plating can be applied
very evenly. Further, the present photopolymerizable
layer has a high photosensitivity, which will bring about
- 22 -
shortening of the exposure time. That is, by use of the
photopolymerizable laminate disclosed in the present
invention, one can enjoy the advantages that a high density
and high precision printed circuit board can be prepared
easily, and also that ~he step of preparing the printed
circuit board can be simplified.
Another superiority of the present invention is
the fact that the photopolymerizable lamina-te of the
present invention is applicable without causing a problem
such as cracks for a more preferable process, in which
the flexible support layer is removed by developing as
such, without peel-off from the photopolymerizable layer,
together with the unexposed portion of the photopolymer-
izable layer.
It can be also applied for preparation of
decorative panels or printing plates.
The present invention is further illustrated by
referring to the following Examples, by which the present
invention is not limited at all.
~ ~3 -
Reference Example l
-
Into a four-neck.ed flask of 2-Q volume equipped
with a droppincJ runnel, a thermometer and a stirrer,168 g
of hexamethylene diisocyanate as the compound (F2), 80 g
of methyl ethyl ketone as the Solvent 1 and 0.6 g of
dibutyltin dilaurate as the catalyst were charged. While
qtirring ths mixture, a mix~re of 286 g of 2-hydroxy-
propyl-acrylate as the compound (Fl) and 65 g of methyl
ethyl ketone as tne Solvent 2 was added dropwise at an
innsx tempera~ure which was controlled to be no~ higher
than 35 C. After the d~opwise addition, stirring wa~
continued at ~0 C fox 30 hours until the characteristic
absoxption o~ the isocyanate yroups at around 2270 cm l
in IR-absorption spectrum was con~irmed to ha~e substan-
tially d~sappeared. Then! as the Solven~ 3, 50 g of
metn~l ethyl ketone was added. This reaction product is
called as C~l.
Reference Example 2
Into the sam~ flask as in Reference Example 1,
~50 ~ of 2,4-toluylene diisocyanate as the compound (F2),
80 g of acetone and 0.6~ y of dibutyltin dilaurate were
cllar~ed, and a mixture oE 336 g of 2--hydroxyp~opyl acrylate
~s the co~lpound (Fl1., an.~2I5 g.ofacetone was added to the
resultant mixture under stirring~ After addition, stir-
ring ~as continued for 25 hours, during which the inner
temperature was controlled at no~ higher than 40 C~ A
part of the xeaction mixture was sampIed and mixed with
equal amouilt of~ ethanol, and the mlxture le~t to stand
at 50 C for one hour. Thls sample was sub~çcted to ~el
pe~neat.ion chr~matoyraph~. As the result, no adduct Qf
tolulyerle diisocyanate.anl.l ethanol ::W~5 r~cognized.and
tolulyene diis~cyanate was confi.cmed to be consumed in
the xeaction Thi~ reac~ion mi~t~lre i~ called as C-2.
~ '
- 2~ 8~
Reference Example 3
Into a thxee-necked flask of one liter volume,
97.7 g of propylene glycol glycidylether diacrylate
(Denacolacrylate DA-9ll, hydroxyl equivalence=222,
produced by Nagase Sangyo Co., Ltd.), 280 g of C-2 as
prepared above, 0.3 g of dibutyltin dilaurate and 75 g of
acetone were charged. Under magnetic stirring, the re-
action was continued at 30 C for 4 hours and further at
15 C for 12 hours~ Completion of the reaction was con
firmed by IR-absorption spectrum. This product is called
as C-3.
Reference Example 4
~ Into the same flask as employed in Reference
Example l, lOQ g of hexamethylene diisocyanate as the
compound (F2), 0.35 g of dibutyltin dilaurate as the
catalyst and 70 g of ethyl acetate as the Solvent l were
charged. -While stirring the mixture, a mixture of 200 g
of polyethylene glycol (ave~age molecular weight 200) as
the compound (F3) was added dropwise over 2 hours. Dur-
ing the addition, the inner temperature was controlled to
be not higher than 40 C by controlling the temperature
of the water bath and the dxopping rate. Further, after
stirring at 40 C for one hour, 134 g of 2-hydroxypropyl
acrylate as the compound (Fl) was added dropwise at an
inner temperature controlled to be not higher than 40 C.
Then, the mixture was stirred at 40 C for 48 hours, and
lO0 g of-ethyl acetate as the Solvent 2 was added to give
a homogeneous solution. This is called as C-4.
Reference Examples 5 - 13
Using the device and the method as described in
Reference Example l, various ~,onomeric components ~Reac-
tion product ~C)] were prepared. The starting m~t~rials
*tra~e mark
6~S
- 25 -
and their a~ounts charged are shown in Table 1. As the
catalyst, in every case, dibutyltin dilaurate was used.
The products in respective Reference examples are called
as C-5 to C-13.
- :'
..
:' ' ,.
8~
- 26 -
Notes for Table l
*l) IPDI: isophorone diisocyanate
*2) HPA: 2-hydroxypropyl acrylate
*3) DNT: HMDI adduct (DURANATE#24A-100, produced by
Asahi Kasei Kogyo Kabushik~ Kaisha)
*4) MEK: methyl ethyl ketone
*5) B-l: 2-hydroxy-3 phenoxypropyl acrylate (ARONIX~
5700, produced by Toa Gosei Kagaku Xogyo
Co., Ltd.)
*6) HMDI: hexamethylene diisocyanate
*7) CHL: HMDI trimethylolpropane adduct (CORONATE~
HL, NCO content 12.8%, 75% ethyl acetate
solution, produced by Nippon Polyurethane
Kogyo Co., Ltd.)
*8) CL: trimethylolpropane toluylene diisocyanate
adduct (CORONATE~L, NCO content 13.2 %, 75 %
ethyl acetate solution, produced by Nippon
Polyurethane Kogyo Co., Ltd.)
*9) B-2: polypropyleneglycol monomethacrylate
(BLEMMER~P-1000 average molecular weight
370, produced by Nippon Yushi Co., Ltd.)
*10) TMHMDI: trimethylhexamethylene diisocyanate
*ll) TDI: toluylene diisocyanate
*12) MDI: diphenylmethane diisocyanate
*13) HPM~: 2-hydroxypropyl methacrylate
t~`~
~trade mark
:
- 27 -
Reference Example 14
Reference Example 4 was repeated except for em-
ploying 96 gof DNT (*3 in Table 1) as the compound (F2),
80 gof methyl ethyl ketone as the Solvent 1, 200 gof poly-
ethylene glycol (average molecular weight 200) as the
compound (F3),52 gof 2-hydroxypropyl acrylate as the com-
pou~d (Fl), 32 gof methyl ethyl ketone as the Solvent 2,
and a separate flask of one liter volume as the reaction
vessel. As the result, the product C-14 was obtained~
Reference Example 15
Into a separable flask of 5-Q volume equipped
with a stirrer and a reflux condenser, 2000 gof deionized
water was charged and 10 g of methyl cellulose (METOLOSE
S~-100, produced by Shinetsu Kagaku Co., Ltd.) and 5 g of
sodium chloride were dissolved therein. With stirring at
75 C, a homogeneous mixture comprising 480 g of meth~l
methacrylate and 20 g of butyl acrylate as the monomers,
2.5 g of azobisisobutyronitrile and 1 g of dodecyl
mercaptan was charged into the solution. About one hour
later, the inner temperature began to be elevated until
reaching 90 C. When the inner temperature lowered :
to 80 C, the water bath was heated to 80 C, whereat the
mixture was stirred for 2 hours and further at 90 C for
one hour. Then, the contents were poured into a metal
sieve o~ 300 mesh and washed with sufficient amount of
water As the result, a polymer in shape of beads with
particle sizes of 100 to 400 ~m was obtained, which was
then dried. This polymer i9 called as B-15. This B-l~
was analyzed by gel permeation chromatography to find that
it had a weight-average molecular weight o~ 176000.
Example 1
Into a 300-ml separable flask equlpped with a
. . _. _ _ . ~ . .. _ . .
*trade mark
.
~. . ;
`- 28 -
bl O O O O O O O ~1 0
0
,~1 o ~ c~ o o o o o I
o o o o ~
~_
cl
o ~ 0 ~ ~ ~ ~0
o
o I I I I I o
U~ ~
,~1 oo o ~ o ~D 00 0 I
,
~1
~ ~ #
,1 ,1 o ~ 0 o ~ 0
~ u~ ~ ¢ ~ t) ¢
, 1 ~ 1 0 ~ C~l O I
~1 01 d` U~ ~ O
U~
O ~
~ ~ cn
cO~ ~
,~ , 1 oo oo ~ o~ o ~ o cJ I
~0 ~ I~ ~ ~ o ,
~_ ~ ~ ~ ~O ~ ~ ~ U~
f::
O * # ~C # ;C ~ H
a H H !~3
C~ H j~ H
~1
;Q~ ~ ~ O 1~ ~0 ~ ~0 ~ '1
;Y; ~
:. ,~
: ' ~
~;~4i~
- 29 -
stirrer, 49 g of B-15 as the binder, 53 g o~ C-l as the
monomeric component, 2 g of benzophenone and 0.2 g of
Michler's ketone as the initiators, Diaresin Blue P
(produced by Mitsubishi Kasei Kogyo Co., Ltd.) as the dye,
0.2 g of benzotriazole and 30 mg o~ p-methoxyphenol as the
additives, and 84 g of ethyl acetate as the solvent were
charged, followed by stirring for 15 hours. Then, a
support of polyethyleneterephthalate film with a thickness
of ~0 ~m was coated by means of a blade coater with the
above mixture, dried on air for 30 minutes and then in an
oven at 60 C for 15 minutes. The photopolymerizable
layer obtained had a thickness of 35 ~m. Next, after a
polyethylene film with a thickness of 25 ~m as the protec-
tive layer was laminated on the photosensitive layer by
pressure rollers, the laminate was bonded onto a copper-
clad laminate by pressure rollers at 80 C, while peeling
o~f the above polyethylene film. This laminate was ex-
posed to light through a nega-mask film at a dose of 100
mJ/cm2 using a ultra-high pressure mercury lamp (Phoenix
~odel 3000, produced by Oak Seisakusho). Subs~quently,
the polyethyleneterephthalate film was peeled off, and the
une.Yposed portion was dissolved and removed by spraying
l,l,l-trichloroethane through a spray nozzle for 120 sec-
onds. As the result, good image was obtained (this is
called as Resist image). It was confirmed that it exhi-
bited a resolution of 40 ~m. Next, when the exposed cop-
pe~ face was etched by spraying a ferric chloride solution
of 50 C for 2 minutes, no image flow was observed.
Example 2
In a 10-Q separable flask eq~ipped with a stir-
rer and a reflux condenser, 1960 g of a binder of
methacrylic resin ~DELPET*70H, produced by Asahi Kasei
Kogyo Kabushiki Kaisha) was dissolved in 3000 g of methyl
ethyl ketone as the solvent under stirring at 70 C, fol-
lowed by addition of 1880 g of C-4 and 332 g of dipentaery-
thritol pentaacrylae (DPHA*produced by Nihon Kayaku Co.,
*trade mark
~2~
- 30 -
L~d.) as the monomeric components, 80 g of benzophenone
and 8 g o~ Michler~s ketone as initiators, 2C g of Dia
Resin Blue-P as the dye, 8 g of benzotriazole and 1.3 g
of p-methoxyphenol as the additives. The mixture was
stirred for 6 hours, and the resultant solution was
applied by means of a coating machine on a 38 ~m poly-
ethylene film as the protective layer, followed by drying
of ~he solvent, to form a photosensitive layer with a
thickness of 40 ~m. This laminate was wound up in a roll
while being covered with a 15 ~m oriented polystyrene
film for the support. This laminate is called as L-2.
Next, by use of AL 700 (lamlnator: product of Asahi Kasei
Kogyo Kabushiki Kaisha) the photosensitive layer supported
on the polystyrene was laminated by adhesion on both sur-
faces of a thru-hole substrate ~copper-clad laminate with
1064 holes with 4.0 mm diameter being bored at intervals
of 4.0 mm, with the thru-hole portions also subjected to
copper plating), while peeling off the polyethylene film,
to obtain a laminated substrate. The heating rolls of
the laminator were set at 80 C. After irradiation of
light at a dose of 120 mJ/cm2 by use of a ultra-high
pressure mercury lamp on the laminated substrate, develop-
ing was conducted by spraying l,l,l-trichloroethane for
120 seconds and the number of the breaking of the hardened
film on the thru-holes was counted. As the result, no
breaking was ohserved. (This test is called as Tenting-I).
Then, the above substrate subjected to develop-
ment processing was subjected to etchiny operation by
spraying ferric chloride solution of 50 C for 2 minutes,
whereby no breaking was observed. (This test is called as
Tenting-II). Next, by using another laminated substrate,
exposure was effected on both surfaces through a land mask
under the above conditions to form hardened films with a
diameter of 4.6 mm on both openings of respective thru-
holes, and thereafter the tests were conducted similarly
as Tenting-I and II. The respective tests are called as
' . .,
' :
,.
~2~8~
- 31 -
Land I and II, but no breaking of hole was observed.
Example 3
A photosensitive composition was prepared
according to the same recipe as in Example 1 except for
using no dye. A photosensitive layer was formed to a
thicXness of 120 ~m on a polyethyleneterephthalate film
with a thickness of 38 ~m, and the lamina-te covered with
polyethylene film was wound up in a roll. While peeling
off the polyethylene film from the laminate, the
laminate was subjected to lamination on a plywood with
rubber rolls. After exposure by means of a high pressure
mercury lamp at a dose of 400 mJ/cm2, the polyethylene-
terephthalate film was peeled of, whereby a tough coated
film was formed on the plywood. This film had a pencil
hardness of 4H. Further, exposure test was conducted by
means of a weather-o-meter for 500 hours. As the result,
no change was observed in appearance, surface hardn~ss and
adhesion to the plywood,
Examples 4 - 17
Using the same laminatQr as in Example 2, dry
film resist laminates were formed according to the same
method. The starting materials and their amounts, thick-
nesses of the resist layers, the protective layers and
supports are listed in Table 2. For respective Examples,
0.2 % of benzotriazole and 0.05 % of p-methoxyphenol were
added based on the total weight of the monomer and the
binder to prepare resist solutions, The laminates
obtained are called as L-4 to L-17, respectively.
In Examples 5, 6, 12, 13, 14 and 17, as d~ffer-
ent from Example 2, protective films were laminated after
formation of photosensitive layers on supports to prepare
laminates shaped in rolls. Further, the support layer
: .. `
:
.
.
~.z~
- 32 -
was peeled off be~ore the developin~ process. The results
of tenting and land tests are also listed in Table 3.
~,
,
8~
-- 33 --
h h ¦
5 _~
~r~
h
a~
h
u~ 5
O o COO O ~`IU\
I~ ~ O~ ~ 00 1~ 1~
_~ _ _ _ _ _ _
~ ~o
u~ 'S ~ ¢ E~
~ b ,~, ,~
'~ h
0 ~0 o o o . U~ ~ o o U~ ô ~ ~ O O .
H 1--1 H H H H H H H H H H H H H
O O O O O O ~')
c~l ~D 0 0~ 0
d _ _ ~, _ ~ _ ~,
C`l ~ ~ ~ ,
d ~O r~ o ,_ U~ ~ ô r) ô ô ô ô _~ ô
~0 ~ O ~ ~D O a~ ~ ~$ ul U) ~D ~ `J u~
O 0~~1 ~ ~ ~D1~ ~ ~ ~1 ~ ~ ~ In ~ ~ u
.~
.~:' ; '
:; "~ ' : . ~ .,
.
`
-
`
,
8~
-- 34 --
~ 0~ u~
~ I I
Q~
h
ta
O ~ 1-- oo ~ oo U~
C~ ~ ~ ~r) ~t ~ ~ ~
O O O O O C`l O
I~ Lr) ~t 00 0 ~ U~
00 Q)
0 ~ 0 ~1 0 ~1 0
?~ ~P~ ~~ ~ ~ ~
.~ 4
~ 0 ~ 0 ~ 0 ~ ~ ~ 0
.~ U~ ~
bO
O _~ ~1 C`l
~1
l l l
~ . ~ 1 .
E~ o ~0 u~ ô co O O O O O O
~rl O O
1:~ ~ ~~1 ~~1 ~t~\ ~ ~'7 ~ `S) ~ ~ ~O 00 a~ ~
H H HH 1--1 H 1--1 H H H H H H H H H H H
O O O ~ O O O
h ~ O O O C~ `D O O
_~
~1
~4
Fq I '
O OO O ~ ~ OO _~ I~ OO _~ O ~ O
~1 00 O O1~ Ot~00 OC~ U)d~ O ~ ~ `I ~ O C) O
~ ~ ~ O ~ t~
o oI~ oo cr~
X ~ ~ X X~
OJ ,
~ ~ o l~
0
~ .
.: ~: : ,.
.
8~5
- 35 -
Table 3
Number of Broken Holes _ __ _ _
Example Tenting I Tenting I_ Land I Land II
2 0 0 0 0
4 0 0 0 0
0 0 0 0
6 0 0 0 0
7 0 0 0 0
8 0 l O
9 0 0 0 0
0 o o o
11 0 1 0 0
12 0 0 o O
13 O O O O
14 0 0 0 0
0 1 0
1~ 0 0 0 0
17 0 0 0 0
,
,
,
- 36 -
Note)
t~1onomeriC component)
M-1: "ARONIX*M-305", produced by Toa Gosei Kagaku
Kogyo Co., Ltd. (main component: pentaerythri-
tol triacrylate).
M-2: D-330~, produced by Nihon Kayaku Co., Ltdo
(main component: dipentaerythritol triacry-
late).
M-3: "EPOXYESTER 70 PA", produced by Kyoei Yushi
Kagaku Kogyo Co., Ltd. (main component:
propyleneglycol diglycidylether-acrylilc acid
adduct).
M-4: "BISCOAT*3700", produced by Osaka Yuki Kagaku
- Kogyo Co., Ltd. (main component: bis~1,5-pen-
tanediol)phthalic anhydride-acrylic acid
ester).
M-5: "EPOXYESTER BP-4PA", produced by Kyoei Yushi
Kagaku Kogyo Co., Ltd.
M-6: "ARONIX 8100", produced by Toa Gosei Kagaku
Kogyo Co., Ltd. (polyfunctional acrylic acid
ester).
M-7: "BISCOAT 823", produced by Osaka Yuki Kagaku
Kogyo Co., Ltd. (non-yellow discoloration type
urethane acrylate 7 average molecular weight
1350).
M-8: R-526*, produced by Kyoei Yushi Kagaku Kogyo
Co., Ltd. (polyester type diacrylate).
*trade mark
.
-
- ; -
.
1248BOS
- 37 -
M-9: "ARONIX M-1200", produced by Toa Gosei Kagaku
Kogyo Co., Ltd. (non-yellow discoloration type
urethane acrylate).
M-10: SP-4010*, produced by Showa Kobunshi Co., Ltd.
(special epoxy acrylate).
(Binders)
B-l: "DELPET 80N", produced by Asahi Kasei Kogyo
Kabushiki Kaisha.
B-2: "STYRON*GP 683", produced by Asahl Kasei Kogyo
Kabushiki Kaisha.
B-3: ACRYPET , produced by Mitsubishi Rayon Co~,
Ltd.
B-4: "DELPET*CR-l", produced by Asahi Kasei Kogyo
Kabushiki Kaisha.
B-5: "DELPET*70H", produced by Asahi Kasei Kogyo
Kabushiki Kaisha.
B-6: "ASAFLEX AFX-810", produced by Asahi Kasei
Kogyo Kabushiki Kaisha,
(Initiators)
I-l: 2,4-diisopropylthioxanthone
- I-2: isopropyl 4-(dimethylamino)benzoate
I-3: benzophenone
I-4: 4,4'-bis(dimethylamino)benzophenone (Michler's
ketone)
*tra~e mark
- 38 -
I-5: fluorein
I-6: dimethylbenzyl ketal
I-7: triphenyl phosphine
I-8: 4-chlorothioxanthone
I-9: Ethyl 4-(dimethylamino)benzoate
I-lOo 4-chlorobenzophenone
~Dyes)
D-l: "Blue-P"
D-2: "Green-C"
D-3: "Blue-K"
D-4: "Blue-G"
(all produced by Mltsubishi Kasei Kogyo Co., Ltd.)
(Protective layer)
P : oriented polypropylene (20~m)
E : polyethylene (38~m)
(Support layer)
S : oriented polystyrene ( 15~m)
T : polyeehvlenet~rephthalate (20~m)
- . . , . :
, .
, .
,~ :
- 39 -
Example 18
On the copper clad laminate laminated with the
photosensitive layer o~tained in Example 1, exposure was
effected through A posi-mask film at a dose of 100 mJ/cm2.
Then, de~eloping was carried out with l,l,1-trichloro-
ethane, followed by the pretreatments in the order of
immersing in Neutraclean C (Shippley Far East Co., Ltd.)
of 40 C for 3 minutes ~ washing with water -~ immersing
in 20 ~ aqueous ammonium persulfate for 1 minute -~ washing
with water ~ immersing in 20 % diluted sul.furic acid ..
for 2 minutes ~ washing with water. Subsequently, copper
plating was conducted under the condition C shown in the
note in Table 4 and then solder plating under the con-
dition E. As the result, no ~low was seen on ~ine lines
of the image. On this image was plastered Cellophane
tape, and the tape was peeled off after sufficient ad-
hesion under pressure with the result that there was no
peel-off of the resist at all. Also, another substrate
subjected to the same pre-treatments as described above
was applied with copper plating according to the condition
D and`E, followed ~urther by solder plating. This product
was also free from peel-off of resist in the tape peeling
test.
Comparative E~ample 1
Using a solution prepared according to the
following composition, a laminate was prepared in the
same manner as in Example 1 (thickness o~ photopolymeri-
zable layer: 40 ~m):
B-15 (prepared in Reference Example 15) 200 g
Trimethylolpropane triacrylate 220 g
Benzophenone. 8 g
Mich~ër'.s~ketone 0.8 g
Benzotriazole 0.8 g
~, :
~ : .
- :
38~
-- ~o --
p-methoxyphenol 0.13 g
Diaresin Blue-P 2 g
Ethyl acetate 300 g-
According to the method as in Example 2~ a
thru-hole substrate was laminated with this laminate, and
tenting and land tests were conducted to obtain the
following results.
TestsNumber of holes broken
Tenting I 8
Tenting II 15
Land I 40
Land II 52
Further, plating test was conducted similarly
as in Example 18. As the result, the hardened photo-
sensitive layer on both sides of the plated image was
peeled off with widths of 0.1 - 0.5 mm.
Example 19
According to the same procedure as in Compara-
tive Example 1, except that 140 g o trimethylolpropane
triacrylate was replaced with C-l, a laminate was pre-
pared. This laminate is called as L-l9.
Examples 20 - 35
Using the dry film resist laminates obtained in
Examples 2, 4 through 17 and 19, the same plating
operations as in Example 18 were repeated, and plating
resistance of the resists was tested. The results are
shown in Table 4. Plating pre-treatments, plating con-
ditions and the results oE tape peeling tests are as
described in the notes in Table 4.
,:
.
,
~z~
- 41 -
Table 4
Plating Condition
ExampleLaminate A-C-E B-C-E A-D-E
2 a a b
21 4 b a a
22 5 a a b
23 6 b b b
24 7 a a a
8 a b a
26 9 a a a
27 lQ a a b
28 11 a a b
29 12 b b b
13 a a a
31 14 a a
32 15 a b b
33 16 b a b
34 17 a a b
19 a b b
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- 42 -
Note)
(Plating pre-treatment conditions)
Condition A: After immersion in an aqueous 50 %
solution of L 5B* produced by Macdamid
Co. at 40 C for 3 minutes, washed with
water, immersed in an aqueous 15 %
ammonium persulfate solution for one
minute, washéd with water, further
immersed in 20 % dil. sulfuric acid
for 2 minutes and washed with water.
Condition B~ After electrolytic defatting in an
aqueous 5 ~ solution of "Okite*90"
produced by Diafloc Co. at a current
density of 4A/dm2 at 50 C for 2
minutes, washed with water, immersed
in an aqueous 15 % ammonium persulfate
solution for one minute, further in -
20 ~ dil. sulfuric acid for 2 minutes
and washed with water.
(Plating conditions)
Condition C: Plating is performed in a plating
solution of "Copper sul~ate conc."
produced by ~apan Metal Finishing Co.
diluted with 19 % sulfuric acid to
3.6-fold at a current density of
2.5 A/dm2 at room temperature for 30
minutes.
Condition D: Platlng is performed is an aqueous
50 % solution of "Pyrodone conc."
produced by Harshaw-Murata Co. at a
current density of 2.5 A/dm2 at 50 C
for 30 minutes.
~`"` *trade mark
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- ~3 -
Condition E With the use of the solder plating
solution (tin/lead=4/6) produced by
Macdamed Co., plating is per~ormed at
a current density of 2 A/dm2 for 10
minutes.
(Tape peeling test evaluation)
a : Resist did not ~eel of~:at all.
b : On both sides of image line, some portions with
width of 100-~m or less and length of l mm or
less were peeled off.
Comparative Example 2
Using the laminate prepared in Comparative
Example 1, plating resistance test was conducted according
to the same method as in Example 18. The plating con-
ditions and the results of tape peeling test are shown
below.
Platin~ condition Results of tape peeling test
A-C-E Resist peeled off with width of
100~m - 200~m and length of 3-5 mm on
both s.ides of image line
B-C-E Resist peeled off with width of
150~m - 250~m and length of 4-10 mm
on both sides of image line
A-D-E Resist peeled off with width of
` 50~m - 150~m and length of 3-5 n~ on
both sides of image line
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