U.S. patent application number 11/044374 was filed with the patent office on 2005-06-23 for thermoset adhesive films.
Invention is credited to Jin, Hwail, Musa, Osama M., Nikolic, Nikola A., Shenfield, David, Wu, Bing, Zhang, Ruzhi.
Application Number | 20050137340 11/044374 |
Document ID | / |
Family ID | 29269750 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050137340 |
Kind Code |
A1 |
Nikolic, Nikola A. ; et
al. |
June 23, 2005 |
Thermoset adhesive films
Abstract
This invention is a film adhesive prepared from an adhesive
composition comprising a polymer system, a film forming rubber
compound, and curing agents for the polymeric system. The polymer
system comprises a base polymer and electron donor and electron
acceptor functionality.
Inventors: |
Nikolic, Nikola A.;
(Princeton, NJ) ; Zhang, Ruzhi; (Somerset, NJ)
; Musa, Osama M.; (Hillsborough, NJ) ; Jin,
Hwail; (La Palma, CA) ; Wu, Bing; (Marina Del
Rey, CA) ; Shenfield, David; (Fountain Valley,
CA) |
Correspondence
Address: |
National Starch and Chemical
10 Finderne Avenue
Bridgewater
NJ
08807
US
|
Family ID: |
29269750 |
Appl. No.: |
11/044374 |
Filed: |
January 27, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11044374 |
Jan 27, 2005 |
|
|
|
10146387 |
May 14, 2002 |
|
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Current U.S.
Class: |
525/200 |
Current CPC
Class: |
C08F 267/10 20130101;
C09J 11/06 20130101; C08L 33/00 20130101; C08L 25/00 20130101; C09J
2301/414 20200801; C09J 2433/00 20130101; C09J 5/10 20130101; C08L
55/00 20130101; C09J 2455/00 20130101; C09J 2425/00 20130101 |
Class at
Publication: |
525/200 |
International
Class: |
C08L 001/00 |
Claims
What is claimed:
1. A film adhesive prepared from materials comprising (i) a rubbery
polymer prepared from acrylic, vinyl, or conjugated diene monomers,
containing no electron donor or acceptor functionality, and having
a weight average molecular weight in the range of 300,000 to
1,500,000; (ii) an independent electron donor compound selected
from the group consisting of vinyl ethers and compounds containing
a carbon to carbon double bond attached to an aromatic ring and
conjugated with the unsaturation in the ring; (iii) an independent
electron acceptor compound; and (iv) a free radical initiator;
characterized in that the film adhesive can be cured within two
minutes at a temperature below 300.degree. C.
2. The film adhesive according to claim 1 in which the rubbery
polymer (i) is an acrylic polymer, a styrene-acrylic copolymer, or
a acrylonitrile-butadiene copolymer.
3. The film adhesive according to claim 1 in which the independent
electron donor compound (ii) is a vinyl ether selected from the
group consisting of bis[4-(vinyloxy)butyl]terephthalate,
bis[4(vinyloxy)butyl] (4-methyl-1,3-phenylene)-biscarbamate,
bis[4-(vinyloxy) butyl] 1,6-hexanediylbiscarbamate,
4-(vinyloxy)-butyl stearate, and bis[4-(vinyloxy) butyl]
(methylenedi-4,1-phenylene)-biscarbamate.
4. The film adhesive according to claim 1 in which the independent
electron donor compound (ii) is a compound containing a carbon to
carbon double bond attached to an aromatic ring and conjugated with
the unsaturation in the ring and are selected from the group
consisting of: 232425
5. The film adhesive according to claim 1 in which the independent
electron acceptor compound (iii) is selected from the group
consisting of fumarates, maleates, acrylates, and maleimides.
6. The film adhesive according to claim 5 in which the independent
electron acceptor compound (iii) is a bismaleimide selected from
the group consisting of N,N'-ethylene-bis-maleimide,
N,N'-butylene-bis-maleim- ide, N,N'-phenylene-bis-maleimide,
N,N'-hexamethylene-bis-maleimide, N,N'-4,4'-diphenyl
methane-bis-maleimide, N,N'-4,4'-diphenyl ether-bis-maleimide,
N,N'-4,4'-diphenyl sulfone-bis-maleimide, N,N'-4,4'-dicyclohexyl
methane-bis-maleimide, N,N'-xylylene-bis-maleimide- , and
N,N'-diphenyl cyclohexane-bis-maleimide.
7. A film adhesive prepared from (i) a rubbery polymer prepared
from acrylic, vinyl, or conjugated diene monomers, substituted with
pendant electron acceptor functionality, and having a weight
average molecular weight in the range of 300,000 to 1,500,000, (ii)
an independent electron donor compound selected from the group
consisting of vinyl ethers and compounds containing a carbon to
carbon double bond attached to an aromatic ring and conjugated with
the unsaturation in the ring; (iii) optionally, an independent
electron acceptor compound; (iv) a free radical initiator;
characterized in that the film adhesive can be cured within two
minutes at a temperature below 300.degree. C.
8. The film adhesive according to claim 7 in which the rubbery
polymer (i) is an acrylic, styrene-acrylic copolymer, or a
acrylonitrile-butadiene copolymer.
9. The film adhesive according to claim 7 in which the independent
electron donor compound (ii) is a vinyl ether selected from the
group consisting of bis[4-(vinyloxy)butyl]terephthalate,
bis[4(vinyloxy)butyl] (4-methyl-1,3-phenylene)-biscarbamate,
bis[4-(vinyloxy) butyl] 1,6-hexanediylbiscarbamate,
4-(vinyloxy)-butyl stearate, and bis[4-(vinyloxy) butyl]
(methylenedi-4,1-phenylene)-biscarbamate.
10. The film adhesive according to claim 7 in which the independent
electron donor compound (ii) is a compound containing a carbon to
carbon double bond attached to an aromatic ring and conjugated with
the unsaturation in the ring and are selected from the group
consisting of: 262728
11. The film adhesive according to claim 7 in which the independent
electron acceptor compound (iii) is selected from the group
consisting of fumarates, maleates, acrylates, and maleimides.
12. The film adhesive according to claim 7 in which the independent
electron acceptor compound (iii) is a bismaleimide selected from
the group consisting of N,N'-ethylene-bis-maleimide,
N,N'-butylene-bis-maleim- ide, N,N'-phenylene-bis-maleimide,
N,N'-4,4'-diphenyl ether-bis-maleimide, N,N'-4,4'-diphenyl
sulfone-bis-maleimide, N,N'-4,4'-dicyclohexyl
methane-bis-maleimide, N,N'-xylylene-bis-maleimide, and
N,N'-diphenyl cyclohexane-bis-maleimide.
13. A film adhesive prepared from (i) a rubbery polymer prepared
from acrylic, vinyl, or conjugated diene monomers, substituted with
pendant electron donor functionality, and having a weight average
molecular weight in the range of 300,000 to 1,500,000, (ii) an
independent electron acceptor compound; (iii) optionally, an
independent electron donor compound selected from the group
consisting of vinyl ethers and compounds containing a carbon to
carbon double bond attached to an aromatic ring and conjugated with
the unsaturation in the ring; and (iv) a free radical initiator;
characterized in that the film adhesive can be cured within two
minutes at a temperature below 300.degree. C.
14. The film adhesive according to claim 13 in which the rubbery
polymer (i) is an acrylic, styrene-acrylic copolymer, or a
acrylonitrile-butadiene copolymer.
15. The film adhesive according to claim 15 in which the
independent electron acceptor compound (ii) is selected from the
group consisting of fumarates, maleates, acrylates, and
maleimides.
16. The film adhesive according to claim 13 in which the
independent electron acceptor compound (ii) is a bismaleimide
selected from the group consisting of N,N'-ethylene-bis-maleimide,
N,N'-butylene-bis-maleimide, N,N'-phenylene-bis-maleimide,
N,N'-hexamethylene-bis-maleimide, N,N'-4,4'-diphenyl
methane-bis-maleimide, N,N'-4,4'-diphenyl ether-bis-maleimide,
N,N'-4,4'-diphenyl sulfone-bis-maleimide, N,N'4,4'-dicyclohexyl
methane-bis-maleimide, N,N'-xylylene-bis-maleimide, and
N,N'-diphenyl cyclohexane-bis-maleimide.
17. The film adhesive according to claim 13 in which the
independent electron donor compound (iii) is a vinyl ether selected
from the group consisting of bis[4-(vinyloxy)butyl]terephthalate,
bis[4(vinyloxy)butyl] (4-methyl-1,3-phenylene)-biscarbamate,
bis[4-(vinyloxy) butyl] 1,6-hexanediylbiscarbamate,
4-(vinyloxy)-butyl stearate, and bis[4-(vinyloxy) butyl]
(methylenedi-4,1-phenylene)-biscarbamate.
18. The film adhesive according to claim 13 in which the
independent electron donor compound (iii) is a compound containing
a carbon to carbon double bond attached to an aromatic ring and
conjugated with the unsaturation in the ring and are selected from
the group consisting of: 293031
19. A rubbery film adhesive prepared from (i) a rubbery polymer
prepared from acrylic, vinyl, or conjugated diene monomers,
substituted with pendant electron donor and pendant electron
acceptor functionality, and having a weight average molecular
weight in the range of 300,000 to 1,500,000, or (ii) a combination
of (a) a rubbery polymer prepared from acrylic, vinyl, or
conjugated diene monomers, substituted with pendant electron donor
functionality and having a weight average molecular weight in the
range of 300,000 to 1,500,000, and (b) a rubbery polymer prepared
from acrylic, vinyl, or conjugated diene monomers, substituted with
pendant electron acceptor functionality and having a weight average
molecular weight in the range of 300,000 to 1,500,000; (iii)
optionally, an independent electron donor compound selected from
the group consisting of vinyl ethers and compounds containing a
carbon to carbon double bond attached to an aromatic ring and
conjugated with the unsaturation in the ring; (iv) optionally, an
independent electron acceptor compound; and (v) a free radial
initiator; characterized in that the film adhesive can be cured
within two minutes at a temperature below 300.degree. C.
20. The film adhesive according to claim 19 in which the rubbery
polymers of (i) and (ii) are acrylics, styrene-acrylic copolymers,
or acrylonitrile-butadiene copolymers, or combinations of
those.
21. The film adhesive according to claim 19 in which independent
electron donor compound (ii) is a vinyl ether selected from the
group consisting of bis[4-(vinyloxy)butyl]terephthalate,
bis[4(vinyloxy)butyl] (4-methyl-1,3-phenylene)-biscarbamate,
bis[4-(vinyloxy) butyl] 1,6-hexanediylbiscarbamate,
4-(vinyloxy)-butyl stearate, and bis[4-(vinyloxy) butyl]
(methylenedi-4,1-phenylene)-biscarbamate.
22. The film adhesive according to claim 19 in which the
independent electron donor compound (ii) is a compound containing a
carbon to carbon double bond attached to an aromatic ring and
conjugated with the unsaturation in the ring and are selected from
the group consisting of: 323334
23. The film adhesive according to claim 19 in which the
independent electron acceptor compound (iii) is selected from the
group consisting of fumarates, maleates, acrylates, and
maleimides.
24. The film adhesive according to claim 19 in which the
independent electron acceptor compound (iii) is a bismaleimide
selected from the group consisting of N,N'-ethylene-bis-maleimide,
N,N'-butylene-bis-maleim- ide, N,N'-phenylene-bis-maleimide,
N,N'-hexamethylene-bis-maleimide, N,N'4,4'-diphenyl
methane-bis-maleimide, N,N'-4,4'-diphenyl ether-bis-maleimide,
N,N'-4,4'-diphenyl sulfone-bis-maleimide, N,N'-4,4'-dicyclohexyl
methane-bis-maleimide, N,N'-xylylene-bis-maleimide- , and
N,N'-diphenyl cyclohexane-bis-maleimide.
Description
[0001] This application is a continuation-in-part of Ser. No.
10/146,387 filed 14 May 2002.
FIELD OF THE INVENTION
[0002] This invention relates to film adhesives, and particularly
film adhesives for use in semiconductor packaging.
BACKGROUND OF THE INVENTION
[0003] A common mode of electronics packaging involves affixing
semiconductor devices onto substrates by means of an adhesive tape.
Epoxy compounds and resins currently are among the most commonly
used materials for current film based adhesive applications, such
as die attach, in which a semiconductor die is attached to a
substrate. In a typical embodiment, a film-forming rubber polymer
is blended with epoxy resins and a hardening agent. These
compositions can then be cured upon application of heat, which
results in the development of a thermoset network. One drawback to
epoxy adhesives is their ultimate latency. Typically, these
materials must be stored at low temperature to avoid premature
advancement of the adhesive. Moreover, the speed of cure for these
compositions is relatively slow making the die-attach operation the
least efficient step in the total assembly manufacturing process
for wirebonded integrated circuit packages. This creates a need for
a film adhesive that can be rapidly cured compared to the
conventional thermoset film adhesives, and particularly to films
containing no epoxy.
SUMMARY OF THE INVENTION
[0004] This invention is a film adhesive prepared from an adhesive
composition comprising a polymer system, a film forming rubber
compound, and curing agents for the polymeric system. In a
preferred embodiment the polymer system contains no epoxy
functionality. The polymer system comprises a base polymer and
electron donor and electron acceptor functionality. The electron
donor and electron acceptor functionality can be pendant from the
base polymer, or can be interdispersed with the base polymer as
independent compounds. In some cases, the base polymer can function
as a film-forming rubber compound. The film can be prepared
directly as a monolayer from the adhesive composition, or from
coating the adhesive composition onto both sides of a thermal
resistant tape substrate.
DETAILED DESCRIPTION OF THE INVENTION
[0005] The polymer system for preparing the film adhesives will
contain a base polymer (hereinafter "polymer" or "base polymer")
and electron donor and electron acceptor functionality. The system
can be segregated into several classes: (1) an unsubstituted base
polymer blended with an independent electron donor compound and an
independent electron acceptor compound; (2) a base polymer
substituted with pendant electron acceptor functionality, blended
with an independent electron donor compound, and optionally an
independent electron acceptor compound; (3) a base polymer
substituted with pendant electron donor functionality, blended with
an independent electron acceptor compound and optionally an
independent electron donor compound; (4) a base polymer substituted
with pendant electron donor and electron acceptor functionality, or
a combination of a base polymer substituted with pendant electron
donor functionality and a base polymer substituted with pendant
electron acceptor functionality, optionally blended with an
independent electron donor compound, or an independent electron
acceptor compound, or both. Preferably, there will be a 1:1 molar
ratio of electron donor to electron acceptor; however, the molar
ratio can range from 0.01-1.0:1.0-0.01.
[0006] A suitable base polymer in the polymer system of the
inventive film adhesive is prepared from acrylic and/or vinyl
monomers using standard polymerization techniques. The acrylic
monomers that may be used to form the base polymer include
.alpha.,.beta.-unsaturated mono and dicarboxylic acids having three
to five carbon atoms and acrylate ester monomers (alkyl esters of
acrylic and methacrylic acid in which the alkyl groups contain one
to fourteen carbon atoms). Examples are methyl acryate, methyl
methacrylate, n-octyl acrylate, n-nonyl methacrylate, and their
corresponding branched isomers, such as, 2-ethylhexyl acrylate. The
vinyl monomers that may be used to form the base polymer include
vinyl esters, vinyl ethers, vinyl halides, vinylidene halides, and
nitriles of ethylenically unsaturated hydrocarbons. Examples are
vinyl acetate, acrylamide, 1-octyl acrylamide, acrylic acid, vinyl
ethyl ether, vinyl chloride, vinylidene chloride, acrylonitrile,
maleic anhydride, and styrene.
[0007] Another suitable base polymer in the polymer system of the
inventive film adhesive is prepared from conjugated diene and/or
vinyl monomers using standard polymerization techniques. The
conjugated diene monomers that may be used to form the polymer base
include butadiene-1,3,2-chlorobutadiene-1,3, isoprene, piperylene
and conjugated hexadienes. The vinyl monomers that may be used to
form the base polymer include styrene, .alpha.-methylstyrene,
divinylbenzene, vinyl chloride, vinyl acetate, vinylidene chloride,
methyl methacrylate, ethyl acrylate, vinylpyridine, acrylonitrile,
methacrylonitrile, methacrylic acid, itaconic acid and acrylic
acid.
[0008] Alternatively, the base polymer can be purchased
commercially. Suitable commercially available polymers include
acrylonitrile-butadiene rubbers from Zeon Chemicals and
styrene-acrylic copolymers from Johnson Polymer.
[0009] In those systems in which the base polymer is substituted
with electron donor and/or electron acceptor functionality, the
degree of substitution can be varied to suit the specific
requirements for cross-link density in the final applications.
Suitable substitution levels range from 6 to 500, preferably from
10 to 200.
[0010] The base polymer, whether substituted or unsubstituted will
have a molecular weight range of 2,000 to 1,000,000. The glass
transition temperature (Tg) will vary depending on the specific
base polymer. For example, the Tg for butadiene polymers ranges
from -100.degree. C. to 25.degree. C., and for modified acrylic
polymers, from 15.degree. C. to 50.degree. C.
[0011] Suitable electron donor functionality includes vinyl ether
groups, vinyl silane groups, and carbon to carbon double bonds
external to an aromatic ring and conjugated with the unsaturation
in the aromatic ring. Suitable electron acceptor groups include
maleimides, acrylates, fumarates and maleates.
[0012] Examples of suitable starting materials for reacting with
complementary functionality on the base polymer in order to add the
electron donor or electron acceptor functionality pendant to the
base polymer include: for electron donor functionality,
hydroxybutyl vinyl ether, cinnamyl alcohol, 1,4
cyclohexane-dimethanol monovinyl ether,
3-isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate,
isoeugenol, and the derivatives of the aforementioned compounds;
for electron acceptor functionality, dioctyl maleate, dibutyl
maleate, dioctyl fumarate, dibutyl fumarate, N-(6-hydroxyhexyl)
maleimide, 6-maleimidocaproic acid, and 3-maleimidopropionic
acid.
[0013] Independent electron donor compounds for blending with the
base polymer include compounds having at least two vinyl ether
groups, or having at least two carbon to carbon double bonds
external to aromatic rings and conjugated with the unsaturation in
the aromatic ring. Suitable divinyl ether examples include
compounds such as bis[4-(vinyloxy)butyl]te- re-phthalate,
bis[4-(vinyloxy)butyl] (4-methyl-1,3-phenylene)biscarbamate,
bis[4-(vinyloxy) butyl] 1,6-hexanediylbiscarbamate,
4-(vinyloxy)butyl stearate, and bis[4-(vinyloxy)butyl]
(methylenedi-4,1-phenylene)biscarbam- ate (sold under the trade
name Vectomer from Morflex, Inc). Exemplary compounds having at
least two carbon to carbon double bonds external to aromatic rings
and conjugated with the unsaturation in the aromatic ring
include:
[0014] the adduct of tricyclodecane-dimethanol and
3-isopropenyl-.alpha.,.- alpha.-dimethylbenzyl isocyanate (m-TMI)
having the structure 1
[0015] the adduct of 2-hydroxyethyl disulfide and M-TMI having the
structure 2
[0016] the adduct of cyanurate/trifunctional isocyanate and
cinnamyl alcohol having the structure 3
[0017] the adduct of 1,3-propandiol and M-TMI having the structure
4
[0018] the adduct of 1,4-butanediol and M-TMI having the structure
5
[0019] and the adduct of cinnamyl alcohol and
1,6-diisocyanatohexane having 6
[0020] These compounds can be prepared by standard synthetic
methods known to those skilled in the art without undue
experimentation.
[0021] Independent electron acceptor compounds for blending with
the base polymer include resins having at least two intramolecular
maleimide, acrylate, fumarate or maleate groups. Examples of
bismaleimides include: N,N'-ethylene-bis-maleimide,
N,N'-butylene-bis-maleimide, N,N'-phenylene-bis-maleimide,
N,N'-hexamethylene-bis-maleimide, N, N'4,4'-diphenyl
methane-bis-maleimide, N, N'4,4'-diphenyl ether-bis-maleimide,
N,N'-4,4'-diphenyl sulfone-bis-maleimide, N,N'-4,4'-dicyclohexyl
methane-bis-maleimide, N,N'-xylylene-bis-maleimide- , N,N'-diphenyl
cyclohexane-bis-maleimide and the like.
[0022] Suitable film forming resins or compounds include acrylic
polymers (sold under the trade name TEISAN RESIN from Nagase
ChemteX Corporation) and acrylonitrile-butadiene elastomers (sold
under the trade name NIPOL from Zeon Chemicals). These materials,
in general, will be present in the adhesive composition from which
the film will be prepared, in an amount ranging from 10% to 70%,
preferably 15% to 50%, by weight of the adhesive formulation. Other
levels may be suitable depending on the end use application, and
optimal levels can be determined without undue experimentation on
the part of the formulator.
[0023] Suitable curing agents for the polymer system are thermal
initiators and photoinitiators, present in an amount of 0.1% to
10%, preferably 0.1% to 5.0%, by weight of the polymer system.
Preferred thermal initiators include peroxides, such as butyl
peroctoates and dicumyl peroxide, and azo compounds, such as
2,2'-azobis(2-methyl-propane- nitrile) and
2,2'-azobis(2-methyl-butanenitrile). A preferred series of
photoinitiators is one sold under the trademark Irgacure by Ciba
Specialty Chemicals. In some formulations, both thermal initiation
and photoinitiation may be desirable; for example, the curing
process can be started by irradiation, and in a later processing
step curing can be completed by the application of heat to
accomplish the thermal cure. In general, these compositions will
cure within a temperature range of 70.degree. C. to 250.degree. C.,
and curing will be effected at a temperature within the range of
ten seconds to three hours. The time and temperature curing profile
of each formulation will vary with the specific electron donor
compound and the other components of the formulation, but the
parameters of a curing profile can be determined by a practitioner
skilled in the art without undue experimentation.
[0024] In some cases, it may be an advantage to add an epoxy
compound or resin to the adhesive composition. Suitable epoxy
compounds or resins include bifunctional and polyfunctional epoxy
resins such as bisphenol A-type epoxy, cresol novolak epoxy, or
phenol novolak epoxy. Another suitable epoxy resin is a
multifunctional epoxy resin from Dainippon Ink and Chemicals, Inc.
(sold under the product number HP-7200). When added to the
formulation, the epoxy will be present in an amount up to 80% by
weight.
[0025] If an epoxy compound is added, the formulation will need to
contain a curing or hardening agent for the epoxy. Suitable curing
agents include amines, polyamides, acid anhydrides, polysulfides,
trifluoroboron, and bisphenol A, bisphenol F and bisphenol S, which
are compounds having at least two phenolic hydroxyl groups in one
molecule. A curing accelerator may also be used in combination with
the curing agent. Suitable curing accelerators include imidazoles,
such as 2-methylimidazole, 2-ethyl-4-methylimidazole,
4-methyl-2-phenylimidazole, and 1-cyanoethyl-2-phenylimidazolium
trimellitate. The curing agents and accelerators are used in
standard amounts known to those skilled in the art.
[0026] Other materials, such as adhesion promoters (epoxides,
silanes), dyes, pigments, and rheology modifiers, may be added as
desired for modification of final properties. Such materials and
the amounts needed are within the expertise of those skilled in the
art.
[0027] Filler particles that enhance the mechanical, electrical
conductivity, or thermal conductivity may also be added. Suitable
conductive fillers are carbon black, graphite, gold, silver,
copper, platinum, palladium, nickel, aluminum, silicon carbide,
boron nitride, diamond, and alumina. Suitable nonconductive fillers
are particles of vermiculite, mica, wollastonite, calcium
carbonate, titania, sand, glass, fused silica, fumed silica, barium
sulfate, and halogenated ethylene polymers, such as
tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl
fluoride, vinylidene chloride, and vinyl chloride. When present,
fillers will be in amounts of 0.1% to 90%, preferably from 5% to
90%, by weight of the formulation.
POLYMER SYNTHETIC EXAMPLES
Example 1
[0028] This example discloses a butadiene/acrylo-nitrile base
polymer containing pendant acrylate (electron acceptor)
functionality. 7
[0029] where x=50, y=5, n=310, p=678, and q=59, based on GPC and
NMR analysis (one skilled in the art will recognize that these
values may vary slightly due to the polymeric character of the
material).
[0030] Carboxylated butadiene/acrylonitrile polymer (50.6 g) (Nipol
1072 from Zeon Chemicals) was solvated in 4-methyl-2-pentanone
(MIBK, 250 mL) in a 500 mL four-necked flask equipped with a
mechanical stirrer, condenser and drying tube. Glycidyl
methacrylate (9.78 g) and tetrabutylphosphonium acetate solution
(0.58 g) (TBPAAC, catalyst, 70% by weight of tetrabutylphosphonium
acid acetate in methanol from Morton International, Inc.) were
added to the mixture with stirring. The mixture was heated to
110.degree. C. and held at that temperature for approximately
twelve hours. The final product has a viscosity of 4870
mPa.multidot.s at ambient temperature and according to titration
results of the residual carboxylic acid of the modified Nipol
rubber, the carboxyl conversion is about 90%. According to GPC
analysis, the weight average molecular weight and the number
average molecular weight of the modified Nipol polymer are 430,500
g/mol and 60,900 g/mol, respectively.
Example 2
[0031] This example discloses a butadiene/acrylonitrile base
polymer with pendant styrenic (electron donor) functionality, 8
[0032] where x=56, y=16, n=401, p=877, and q=76 based on GPC and
NMR analysis (one skilled in the art will recognize that these
values may vary slightly due to the polymeric character of the
material).
[0033] Carboxylated butadiene/acrylonitrile polymer (38.0 g) (Nipol
1072 from Zeon Chemicals) was solvated in 4-methyl-2-pentanone
(MIBK, 255 mL) in a 500 mL four-necked flask equipped with a
mechanical stirrer, condenser and drying tube. Isoeugenol glycidyl
ether (11.43 g) and tetrabutyl-phosphonium acetate solution (0.62
g) (TBPAAC, catalyst, 70% by wetight of tetrabutylphosphonium acid
acetate in methanol from Morton International, Inc.) were added
into the mixture with stirring. The mixture was heated to
110.degree. C. and held at that temperature for approximately
fourteen hours. According to titration results of the residual
carboxylic acid of the modified Nipol rubber, the carboxyl
conversion is about 87%. The product was purified by precipitation
in methanol three times. According to GPC analysis, the weight
average molecular weight and the number average molecular weight of
the modified Nipol polymer are 554,400 g/mol and 89,100 g/mol,
respectively.
Example 3
[0034] This example discloses a butadiene/acrylonitrile base
polymer with pendant styrenic (electron donor) functionality, 9
[0035] where x=49, y=7, n=310, p=739, and q=59 based on GPC and NMR
analysis (one skilled in the art will recognize that these values
may vary slightly due to the polymeric character of the
material).
[0036] Carboxylated butadiene/acrylonitrile polymer (53.8 g) (Nipol
1072 from Zeon Chemicals) was solvated in 4-methyl-2-pentanone
(MIBK, 360 mL) in a 1 L four-necked flask equipped with a
mechanical stirrer, condenser and drying tube. Glycidyl
N-(3-isopropenyl-.alpha.,.alpha.-dimethylbenzyl- ) carbamate (14.8
g) and tetrabutylphosphonium acetate solution (0.54 g) (TBPMC,
catalyst) were added into the mixture with stirring. The mixture
was heated to 105.degree. C. and held at that temperature for
approximately fifteen hours. The final product has a viscosity of
2000 mPa.multidot.s at ambient temperature and according to
titration results, the carboxyl conversion is about 88%. According
to GPC analysis, the weight average molecular weight and the number
average molecular weight of the modified Nipol polymer are 666,000
g/mol and 75,600 g/mol, respectively.
Example 4
[0037] This example discloses a butadiene/acrylonitrile base
polymer with pendant cinnamyl (electron donor) functionality,
10
[0038] A solution of carboxylated butadienelacrylonitrile polymer
(one molar equivalent based on the carboxylic acid) in toluene is
reacted with excess thionyl chloride at 50.degree. C. for
approximately fourteen hours. The excess thionyl chloride and the
solvent are removed under reduced pressure to afford the
butadiene/acrylonitrile polymer with pendant acid chloride.
[0039] One molar equivalent of cinnamyl alcohol and one molar
equivalent of triethylamine are mixed in dry toluene at 0.degree.
C., to which is added the butadiene/acrylonitrile polymer with
pendant acid chloride dissolved in dry toluene (one molar
equivalent based on the acid chloride). The mixture is allowed to
react overnight. The product is purified by precipitation in
methanol three times.
Example 5
[0040] This example discloses a butadiene/acrylonitrile base
polymer with pendant cinnamyl (electron donor) functionality,
11
[0041] One molar equivalent of cinnamyl amine and one molar
equivalent of triethylamine are mixed in dry toluene at 0.degree.
C., to which is added the butadiene/acrylonitrile polymer with
pendant acid chloride dissolved in dry toluene (one molar
equivalent based on the acid chloride). The mixture is allowed to
react overnight. The product is purified by precipitation in
methanol three times.
Example 6
[0042] This example discloses a butadiene/acrylonitrile base
polymer with pendant styrenic (electron donor) functionality,
12
[0043] One molar equivalent of isoeugenol and one molar equivalent
of triethylamine are mixed in dry toluene at 0.degree. C., to which
is added the butadiene/acrylonitrile polymer with pendant acid
chloride dissolved in dry toluene (one molar equivalent based on
the acid chloride). The mixture is allowed to react overnight. The
product is purified by precipitation in methanol three times.
Example 7
[0044] This example discloses a butadiene/acrylonitrile base
polymer with pendant styrenic (electron donor) functionality,
13
[0045] One molar equivalent of 4-vinyl benzyl amine and one molar
equivalent of triethylamine are mixed in dry toluene at 0.degree.
C., to which is added the butadiene/acrylonitrile polymer with
pendant acid chloride dissolved in dry toluene (one molar
equivalent based on the acid chloride). The mixture is allowed to
react overnight. The product is purified by precipitation in
methanol three times.
Example 8
[0046] This example discloses a butadiene/acrylonitrile base
polymer with pendant vinyl ether (electron donor) functionality,
14
[0047] One molar equivalent of 4-hydroxybutyl vinyl ether and one
molar equivalent of triethylamine are mixed in dry toluene at
0.degree. C., to which is added the butadiene/acrylonitrile polymer
with pendant acid chloride dissolved in dry toluene (one molar
equivalent based on the acid chloride). The mixture is allowed to
react overnight. The product is purified by precipitation in
methanol three times.
Example 9
[0048] This example discloses a butadiene/acrylonitrile base
polymer with pendant vinyl ether (electron donor) functionality,
15
[0049] One molar equivalent of 2-aminoethyl vinyl ether and one
molar equivalent of triethylamine are mixed in dry toluene at
0.degree. C., to which is added the butadiene/acrylonitrile polymer
with pendant acid chloride dissolved in dry toluene (one molar
equivalent based on the acid chloride). The mixture is allowed to
react overnight. The product is purified by precipitation in
methanol three times.
Example 10
[0050] This example discloses a hydroxylated styrene/butadiene base
polymer with pendant styrenic (electron donor) functionality,
16
[0051] One molar equivalent (based on hydroxyl function) of
hydroxylated styrene/butadiene polymer is solvated in dry toluene
at 90.degree. C. under nitrogen, followed by the addition of one
molar equivalent of 3-isopropenyl-.alpha.,.alpha.-dimethylbenzyl
isocyanate (m-TMI) together with 0.07% of dibutyltin dilaurate
(catalyst) based on the total amount of reactants. The resulting
mixture is heated for an additional twenty-four hours under
nitrogen. After removal of the solvent under reduced pressure, the
product is obtained in almost quantitative yield.
Example 11
[0052] This example discloses a hydroxylated styrene/butadiene base
polymer having pendant styrenic (electron donor) functionality,
17
[0053] One molar equivalent of butadiene/styrene polymer based on
the 1,2-vinyl bonds is solvated in dry toluene under nitrogen and
0.3 molar equivalent of 2-mercaptoethanol is added into the
mixture, followed by heating to 75.degree. C. A solution of
azodiisobutyronitrile (AIBN) in toluene is then added to the
mixture. The mixture is stirred at 75.degree. C. for 7 hours. The
product is purified by precipitation in methanol three times.
[0054] One molar equivalent (based on hydroxyl function) of
hydroxylated styrene/butadiene polymer prepared as above is
solvated in dry toluene at 90.degree. C. under nitrogen, followed
by the addition of one molar equivalent of
3-isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate (m-TMI)
together with 0.07% of dibutyltin dilaurate (catalyst) based on the
total amount of reactants. The resulting mixture is heated for an
additional twenty-four hours under nitrogen. After removal of the
solvent under reduced pressure, the product is obtained in almost
quantitative yield.
Example 12
[0055] This example discloses a hydroxylated styrene/butadiene base
polymer having pendant maleimide (electron acceptor) functionality,
18
[0056] One molar equivalent (based on hydroxyl function) of
hydroxylated styrene/butadiene polymer prepared as in Example 11 is
solvated in dry toluene at 90.degree. C. under nitrogen, followed
by the addition of one molar equivalent of 6-maleimidocaproic acid
in toluene. Catalytic amount of sulfuric acid is then introduced
into the mixture. The mixture is heated to reflux and water
generated during the reaction is removed by azeotrope. The reaction
is run overnight. The product is purified by precipitation in
methanol three times.
Example 13
[0057] This example discloses a polybutadiene base polymer with
pendant styrenic (electron donor) functionality, 19
[0058] One molar equivalent (based on anhydride function) of
polybutadiene adducted with maleic anhydride (trade name: Ricon 131
MA20, produced by Sartomer Company) is solvated in acetone,
followed by the dropwise addition of one molar equivalent of
cinnamyl amine. The reaction mixture is stirred for 6 hours. After
acetone is removed by reduced pressure, the polymer is solvated in
toluene and the product is purified by precipitation in methanol
three times.
Example 14
[0059] This example discloses a styrene/acrylic base polymer with
pendant acrylate (electron acceptor) functionality. 20
[0060] where m=11 based on GPC and NMR analysis (one skilled in the
art will recognize that this value may vary slightly due to the
polymeric character of the material).
[0061] In a 500 mL four-necked flask equipped with a mechanical
stirrer, condenser, addition funnel and a N.sub.2 inlet, was
charged with 45.02 g of a styrene-acrylic polymer (Joncryl 587 from
Johnson Polymer) in methylene chloride (100 mL). After the polymer
was solvated under nitrogen at room temperature, the solution was
cooled to 0.degree. C. and 6.83 g of triethylamine was added to the
mixture. To this resulting mixture was added dropwise 6.11 g of
acryloyl chloride. The mixture was allowed to react for an
additional 6 hours. After washing with aqueous solutions several
times until the aqueous phase is neutral, the resulting organic
layer was dried over Mg.sub.2SO.sub.4 and silica gel. After the
solvents were removed under reduced pressure, a white solid was
obtained.
Example 15
[0062] This example discloses a styrene/acrylic base polymer with
pendant styrenic (electron donor) functionality, 21
[0063] where m=11 based on GPC and NMR analysis (one skilled in the
art will recognize that this value may vary slightly due to the
polymeric character of the material).
[0064] In a 1 L four-necked flask equipped with a mechanical
stirrer, condenser, addition funnel and a N.sub.2 inlet, was
charged with 126.7 g of a styrene acrylic polymer (Joncryl 587 from
Johnson Polymer) in methyl ethyl ketone (620 mL). After the polymer
was solvated at the refluxing temperature of the solvent under
nitrogen, 40.58 g of 3-isopropenyl-.alpha.,.alpha.-dimethylbenzyl
isocyanate (m-TMI) was added to the mixture together with 0.12 g of
dibutyltin dilaurate (catalyst). The resulting mixture was heated
for an additional twenty-four hours under nitrogen. After removal
of the solvent under reduced pressure, a white solid was obtained
in almost quantitative yield. According to GPC analysis, the weight
average molecular weight and the number average molecular weight of
the modified styrene-acrylic polymer are 15,600 g/mol and 8,400
g/mol, respectively. According to DSC analysis, the glass
transition temperature of the modified styrene-acrylic polymer is
approximately 40.degree. C.
ADHESIVE FILM EXAMPLES
Example 16
[0065] An adhesive film was prepared from a polymer system
comprising an unsubstituted acrylic/rubber base polymer, an
independent electron acceptor resin, an independent electron donor
resin, and an epoxy resin, which components and parts by weight
used are identified in Table 1. The film formulation also contained
a radical initiator, hardeners for the epoxy, a filler and adhesion
promoters.
1TABLE 1 Component Chemical Class Parts or Function Source by wt.
Base polymer SG-80DR 5 Acrylic rubber Nagase ChemteX Corp. Electron
acceptor Matrimid 5292A 3 Bismaleimide Ciba Specialty Chemicals
Corporation Electron donor Adduct of tricyclodecane- 2.5 Structure
I dimethanol/m-TMI Epoxy HP-7200H 3.5 Dainippon Ink and Chemicals,
Inc.
[0066] The electron donor had the following structure: 22
[0067] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
Example 17
[0068] An adhesive film was prepared from a polymer system
comprising a poly(butadiene) base polymer substituted with pendant
electron acceptor functionality, an independent electron acceptor
resin, an independent electron donor resin, and an epoxy resin,
which components and parts by weight used are identified in Table
2. The film formulation also contained a radical initiator,
hardeners for the epoxy, and adhesion promoters.
2TABLE 2 Component Chemical Class Parts or Function Source by wt.
Butadiene base polymer Polymer from Example 1. 2 substituted with
pendant electron acceptor functionality Electron acceptor Matrimid
5292A 1 Bismaleimide Ciba Specialty Chemicals Corporation Electron
donor Adduct of tricyclodecane- 2.5 Structure I dimethanol/m-TMI
Epoxy HP-7200H 3.5 Dainippon Ink and Chemicals, Inc.
[0069] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
Example 18
[0070] An adhesive film was prepared from a polymer system
comprising a styrene/acrylic base polymer substituted with pendant
electron donor functionality, an independent electron acceptor
resin, an independent electron donor resin, and an
acrylonitrile/butadiene rubber, which components and parts by
weight used are identified in Table 3. The film formulation also
contained a radical initiator and adhesion promoters.
3 TABLE 3 Component Chemical Class Parts or Function Source by wt.
Sytrene/acrylic base polymer Polymer from 2 substituted with
pendant Example 15 electron donor functionality Electron acceptor
Matrimid 5292A 5 Bismaleimide Ciba Specialty Chemicals Corporation
Electron donor Adduct of 1.75 Structure I tricyclodecane-
dimethanol/m-TMI Acrylonitrile/butadiene Zeon Chemicals 4
rubber
[0071] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
Example 19
[0072] An adhesive film was prepared from a polymer system
comprising a styrene/acrylic base polymer substituted with pendant
electron donor functionality, an acrylonitrile/butadiene base
polymer substituted with pendant electron donor functionality, an
independent electron acceptor resin, an independent electron donor
resin, which components and parts by weight used are identified in
Table 4. The film formulation also contained a radical initiator,
filler, and adhesion promoters.
4TABLE 4 Component Chemical Class Parts or Function Source by wt.
Sytrene/acrylic base polymer Polymer from Example 2 substituted
with pendant 15 electron donor functionality
Acrylonitrile/butadiene base Polymer from Example 2 4 polymer
substituted with pendant electron donor functionality Electron
acceptor Matrimid 5292A 5 Bismaleimide Ciba Specialty Chemicals
Corporation Electron donor Adduct of 1.8 Structure I
tricyclodecane- dimethanol/m-TMI
[0073] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
Example 20
[0074] An adhesive film was prepared from a polymer system
comprising a acrylonitrile/butadiene base polymer substituted with
pendant electron donor functionality, an independent electron
acceptor resin, an independent electron donor resin, and an epoxy,
which components and parts by weight used are identified in Table
5. The film formulation also contained a radical initiator,
hardeners for the epoxy, filler, and adhesion promoters.
5 TABLE 5 Component Chemical Class Parts or Function Source by wt.
Acrylonitrile/butadiene base Polymer from Example 2 2.5 polymer
substituted with pendant electron donor functionality Electron
acceptor Matrimid 5292A 3 Bismaleimide Ciba Specialty Chemicals
Corporation Electron donor Adduct of 2.5 Structure I
tricyclodecane- dimethanol/m-TMI Epoxy HP-7200H 3.5 Dainippon Ink
and Chemicals, Inc.
[0075] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
Example 21
[0076] An adhesive film was prepared from a polymer system
comprising a acrylonitrile/butadiene base polymer substituted with
pendant electron donor functionality, an independent electron
acceptor resin, an independent electron donor resin, and an epoxy,
which components and parts by weight used are identified in Table
6. The film formulation also contained a radical initiator,
hardeners for the epoxy, filler, and adhesion promoters.
6 TABLE 6 Component Chemical Class Parts or Function Source by wt.
Acrylonitrile/butadiene base Polymer from Example 3 2.5 polymer
substituted with pendant electron donor functionality Electron
acceptor Matrimid 5292A 3 Bismaleimide Ciba Specialty Chemicals
Corporation Electron donor Adduct of 2.5 Structure I
tricyclodecane- dimethanol/m-TMI Epoxy HP-7200H 3.5 Dainippon Ink
and Chemicals, Inc.
[0077] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
Example 22
[0078] An adhesive film was prepared from a polymer system
comprising an acrylonitrile/butadiene base polymer substituted with
pendant electron acceptor functionality, a styrene/acrylic base
polymer substituted with pendant electron donor functionality, an
independent electron acceptor resin, an independent electron donor
resin, which components and parts by weight used are identified in
Table 7. The film formulation also contained a radical
initiator.
7TABLE 7 Component Chemical Class Parts or Function Source by wt.
Acrylonitrile/butadiene base Polymer from Example 1 2.5 polymer
substituted with pendant electron donor functionality
Styrene/acrylic base polymer Polymer from Example 3 substituted
with pendant 15 electron donor functionality Electron acceptor
Matrimid 5292A 5 Bismaleimide Ciba Specialty Chemicals Corporation
Electron donor Adduct of 1.8 Structure I tricyclodecane-
dimethanol/m-TMI
[0079] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
COMPARATIVE ADHESIVE FILM EXAMPLE
Example 23
[0080] This example discloses an adhesive film prepared with a
polymeric system containing an acrylonitrile/butadiene base
polymer, and epoxy resin, and no electron donor nor electron
acceptor functionality. The formulation also contained a phenol
novolak resin and curing agents. The formulation components and
parts by weight are disclosed in Table 8.
8 TABLE 8 Component Chemical Class Parts or Function Source by wt.
Acrylonitrile/butadiene Nipol 1072 2.7 rubber Zeon Chemicals Epoxy
HP-7200H 3.5 Dainippon Ink and Chemicals, Inc. Phenol Novolak resin
HRJ-1166 1 Schenectady International Inc.
[0081] The film formulation was prepared by mixing the components
in methyl ethyl ketone with stirring, followed by vacuum degassing.
The varnish obtained was coated to a thickness of 2 mil onto a 5
mil thick silicone-treated release-liner and then dried by heating
at 100.degree. C. for 10 minutes to form a partially cured adhesive
film with a thickness of 1 mil.
PERFORMANCE EXAMPLES
Example 24
[0082] A sample of each film produced in Examples 16-22 and
Comparative Example 23 was used to bond a 100 by 100 square mil
silicon die to a PI flex substrate at 120.degree. C. in 5 seconds
and cured at 180.degree. C. for one minute. The die shear strength
of these bare packages was measured at 180.degree. C. on a Dage
Series 4000 Bondtester.
[0083] The results are disclosed in Table 9 and demonstrate that
the inventive films have superior adhesive strength.
9TABLE 9 DIE SHEAR STRENGTH in Kg Force @ 180.degree. C. Cure
condition 180.degree. C./1 min Die shear strength measure
180.degree. C. temperature Example 16 1.86 Example 17 0.90 Example
18 2.22 Example 19 1.93 Example 20 2.78 Example 21 2.80 Example 22
3.00 Comparative Example 23 0.26
[0084] In a particular embodiment, the film forming polymers will
be based on rubbery polymers having a weight average molecular
weight (Mw) within the range of 300,000 to 1,500,000, and will be
prepared from acrylic, vinyl, or conjugated diene monomers. These
polymers will be the base for an electron donor/electron acceptor
adhesive system, by which it is meant that some of the compounds in
the system will be electron donors and some will be electron
acceptors. In general, electron donor refers to an olefin compound
that contains a carbon to carbon double bond with an
electron-donating group, for example, vinyl ethers and compounds
containing a carbon to carbon double bond attached to an aromatic
ring and conjugated with the unsaturation in the ring; electron
acceptor refers to an olefin compound that contains a carbon to
carbon double bond with an electron-withdrawing group, for example,
fumarates, maleates, acrylates, and maleimides. Specific compounds
are disclosed earlier in this specification.
[0085] The base rubbery polymer will be chosen from polymers
containing no electron donor or acceptor functionality; polymers
substituted with pendant electron donor functionality; polymers
substituted with pendant electron acceptor functionality; polymers
substituted with both electron donor and electron acceptor
functionality; and a combination of polymers, one or more
substituted with electron donor functionality and one or more
substituted with electron acceptor functionality. In the case in
which the rubbery polymers have no electron donor or acceptor
functionality, the adhesive system will contain independent
compounds having electron donor functionality and electron acceptor
functionality. In the case in which the rubbery polymers have
either electron donor or electron acceptor functionality, the
adhesive system will contain independent compounds having electron
acceptor functionality or electron donor functionality,
respectively, in order to form a complete electron donor/electron
acceptor system. It is optional to add additional electron donor or
electron acceptor functionality to the adhesive systems.
[0086] The prepared films of this invention are suitably used for
attaching semiconductor chips to substrates and for this purpose
can be cured within two minutes at a temperature or temperature
range below 300.degree. C.
[0087] As would be understood by those skilled in the art, when the
electron donor and electron acceptor functionality is added as
independent compounds or polymers, those materials preferably
should be compatible with the rubbery polymer. Compatible in this
sense means that the compounds are capable of forming a homogenous
intimate mixture without separation from the rubbery polymer into
two or more phases during film preparation and after curing.
Example 25
[0088] Seven film adhesives, identified as Examples 25 A through G,
were prepared from various rubbery polymers and independent
electron donor and electron acceptor compounds. The electron donor
compound used had two end styrenic functionalities and a
dicyclopentadiene backbone. The electron acceptor compound used was
a bismaleimide sold under the tradename Anilix-MI. The rubbery
polymers used in the adhesive formulation are indicated in Table 10
as polymers H through N and were the following:
[0089] H: nitrile-butadiene rubber (Nipol 1072J, Zeon);
[0090] I: proprietary carboxyl terminated nitrile butadiene and
epoxy adduct;
[0091] J: proprietary carboxyl terminated nitrile butadiene and
epoxy adduct;
[0092] K: proprietary carboxyl terminated nitrile butadiene and
epoxy adduct;
[0093] L: acrylic rubber (Nagase, SG-8H DR)
[0094] M: acrylic rubber (Nagase, SG-P3 DR)
[0095] N: vinyl terminated nitrile butadiene (Hycarl300x43,
Noveon)
[0096] The compositions, including the weight average molecular
weight and glass transition temperature (Tg) of the rubbery
polymers are recorded in Table 10. The components of the film
adhesives were blended with methyl ethyl ketone (solvent) and
coated onto a release liner to a thickness of approximately 25
.mu.m. The solvent was evaporated off at a temperature of
99.degree. C. for three minutes, and then the adhesive on release
liner was passed through a roll laminator. Examples 25A, B, C, D,
and G were rolled at 93.degree. C.; Examples 25E and F were rolled
at 140.degree. C. Each adhesive (on release liner) was applied to a
substrate with the adhesive contacting the substrate. The release
liner was removed and a silicon chip contacted with the adhesive
with temperature and pressure; Examples 25A, B, C, D, and G were
contacted at 120.degree. C. and 2 kg pressure; Examples 25E and F
were contacted at 170.degree. C. and 2 kg pressure. Die shear
strength (DSS) was tested at 245.degree. C. after 180.degree. C.
and one minute cure. Commercially acceptable die shear strengths
preferably are greater than 3.0. The Examples show that high
molecular weight rubbery polymers are needed in order to obtain
acceptable die shear strengths.
10TABLE 10 Composition in Parts by Weight and Die Shear Strength of
Film Adhesives Containing Rubbery Polymers Mw in Tg Ex Ex Ex Ex Ex
Ex Ex Polymer 000 .degree. C. 25A 25B 25C 25D 25E 25F 25G H 320 -22
7.00 I 85 -9 7.00 J 32 -15 7.00 K 15 40 7.00 L 350 0 7.00 M 1000 0
7.00 N 13 -45 7.00 Electron 3.00 3.00 3.00 3.00 3.00 3.00 3.00
Donor Electron 5.00 5.00 5.00 5.00 5.00 5.00 5.00 Accep- tor Perox-
0.60 0.60 0.60 0.60 0.60 0.60 0.60 ide Total 15.60 15.60 15.60
15.60 15.60 15.60 15.60 solids ppw DSS 3.3 2.2 1.5 0.9 4.9 3.5
1.6
* * * * *