U.S. patent application number 14/391569 was filed with the patent office on 2015-03-05 for adhesive composition, adhesive film, and bonding method.
The applicant listed for this patent is Tokyo Ohka Kogyo Co., Ltd.. Invention is credited to Hirofumi Imai, Atsushi Kubo, Toshiyuki Ogata, Koki Tamura, Takahiro Yoshioka.
Application Number | 20150059976 14/391569 |
Document ID | / |
Family ID | 49327478 |
Filed Date | 2015-03-05 |
United States Patent
Application |
20150059976 |
Kind Code |
A1 |
Tamura; Koki ; et
al. |
March 5, 2015 |
ADHESIVE COMPOSITION, ADHESIVE FILM, AND BONDING METHOD
Abstract
An adhesive composition including a block copolymer. An adhesive
layer formed by using the adhesive composition has a Young's
modulus of 0.1 GPa or greater at 23.degree. C., a storage modulus
(G') of 1.5.times.10.sup.5 Pa or less at 220.degree. C., and a loss
factor (tan .sigma.) of 1.3 or less at 220.degree. C.
Inventors: |
Tamura; Koki; (Kawasaki-shi,
JP) ; Imai; Hirofumi; (Kawasaki-shi, JP) ;
Ogata; Toshiyuki; (Kawasaki-shi, JP) ; Kubo;
Atsushi; (Kawasaki-shi, JP) ; Yoshioka; Takahiro;
(Kawasaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tokyo Ohka Kogyo Co., Ltd. |
Kawasaki-shi |
|
JP |
|
|
Family ID: |
49327478 |
Appl. No.: |
14/391569 |
Filed: |
March 14, 2013 |
PCT Filed: |
March 14, 2013 |
PCT NO: |
PCT/JP2013/057208 |
371 Date: |
October 9, 2014 |
Current U.S.
Class: |
156/334 ;
428/355BL; 525/324 |
Current CPC
Class: |
H01L 21/6835 20130101;
C09J 153/025 20130101; H01L 2221/6834 20130101; C09J 5/00 20130101;
C09J 7/20 20180101; H01L 2221/68327 20130101; C09J 2453/00
20130101; H01L 2221/68318 20130101; Y10T 428/2883 20150115; C09J
153/00 20130101; C09J 2203/326 20130101; H01L 2221/68381 20130101;
C09J 7/387 20180101 |
Class at
Publication: |
156/334 ;
428/355.BL; 525/324 |
International
Class: |
C09J 153/00 20060101
C09J153/00; C09J 5/00 20060101 C09J005/00; C09J 7/02 20060101
C09J007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 13, 2012 |
JP |
2012-092204 |
Mar 8, 2013 |
JP |
2013-047374 |
Claims
1. An adhesive composition, comprising: a block copolymer, wherein
an adhesive layer formed by using the adhesive composition has a
Young's modulus of 0.1 GPa or greater at 23.degree. C., a storage
modulus (G') of 1.5.times.10.sup.5 Pa or less at 220.degree. C.,
and a loss factor (tan .sigma.) of 1.3 or less at 220.degree.
C.
2. The adhesive composition according to claim 1, wherein the block
copolymer is a diblock copolymer, a triblock copolymer, or a
combination thereof.
3. The adhesive composition according to claim 2, wherein the block
copolymer includes a styrene group.
4. The adhesive composition according to claim 3, wherein both
terminals of a main chain of the block copolymer are styrene
groups.
5. The adhesive composition according to claim 3, wherein a styrene
group content of the block copolymer is in a range of 10% by weight
to 65% by weight.
6. The adhesive composition according to claim 1, wherein a weight
average molecular weight of the block copolymer is in a range of
50,000 to 150,000.
7. The adhesive composition according to claim 1, wherein the block
copolymer is a hydrogenated product.
8. The adhesive composition according to claim 1, wherein the block
copolymer includes a unit of which a glass transition temperature
is 23.degree. C. or lower.
9. The adhesive composition according to claim 1 which is used for
adhering a wafer and a support.
10. The adhesive composition according to claim 9, wherein the
wafer is a wafer which is subjected to a thinning process after
adhered to the support.
11. The adhesive composition according to claim 9, wherein the
wafer is a wafer which is exposed in an environment of 220.degree.
C. or higher after adhered to the support.
12. The adhesive composition according to claims 1, wherein a
content of the block copolymer with respect to a polymer included
in the adhesive composition is 15% by weight or greater.
13. An adhesive film comprising: a film; and an adhesive layer
provided on the film, wherein the adhesive layer contains the
adhesive composition according to claim 1.
14. A bonding method, comprising: bonding a support to a wafer by
using the adhesive composition according to claim 1.
15. The adhesive composition according to claim 4, wherein a
styrene group content of the block copolymer is in a range of 10%
by weight to 65% by weight.
16. The adhesive composition according to claim 3, wherein the
block copolymer is a hydrogenated product.
17. The adhesive composition according to claim 4, wherein the
block copolymer is a hydrogenated product.
18. The adhesive composition according to claim 5, wherein the
block copolymer is a hydrogenated product.
19. The adhesive composition according to claim 6, wherein the
block copolymer is a hydrogenated product.
Description
TECHNICAL FIELD
[0001] The present invention relates to an adhesive composition, an
adhesive film, and a bonding method.
BACKGROUND ART
[0002] As an adhesive composition forming an adhesive layer for
bonding a sheet or the like onto a ground member such as a
semiconductor wafer (hereinafter, referred to as wafer), an
adhesive composition forming an adhesive layer provided on an
adhesive sheet as described in PTL 1 is known.
CITATION LIST
Patent Literature
[0003] [PTL 1] Japanese Unexamined Patent Application, Publication
No. H11-343469 (published on Dec. 14, 1999)
SUMMARY OF INVENTION
Technical Problem
[0004] Products such as a mobile telephone, digital AV equipment
and an IC card have been improved to have more sophisticated
functions. This gives rise to an increase in a demand that
semiconductor silicon chips (hereinafter, referred to as chips)
provided in the products are downsized and thinned so that silicon
can be provided with higher density in a package. For example, for
an integrated circuit in which a plurality of chips are provided in
one package, such as a CSP (chip size package) or an MCP
(multi-chip package), there is a demand that the chips be thinned.
In order to realize the chips to have a higher density in the
package, it is necessary for chips to be thinned to have a
thickness in a range of 25 .mu.m to 150 .mu.m.
[0005] By a grinding process, wafers (hereinafter, referred to as
wafers) which serve as bases for the respective chips are thinned.
Thus, the strength of the wafers becomes weakened. With the
strengths of the wafers being weakened, it is easy for cracks or
warpages to be formed in the wafer. In addition, the wafers
weakened in strength by the thinning are not easily automatically
carried and thus, need to be carried manually. As can be understood
from this, handling of the wafers is troublesome.
[0006] As a countermeasure, a wafer handling system is developed
which adds strengths to the wafers. According to the wafer handling
system, a plate called a support plate, which is made from glass,
rigid plastic, or the like is bonded to the wafers to be thinned so
that the strength of the wafer is held, and the wafers are
prevented from being cracked or warped. Since the strength of the
wafers can be secured by the wafer handling system, it is possible
to automatically carry the semiconductor wafers after the thinning
process.
[0007] In the wafer handling system, the wafers and the support
plate are bonded to each other by using an adhesive layer formed by
an adhesive tape, a thermoplastic resin, an adhesive, or the like.
Then, in a state of being bonded to the support plate by the
adhesive layer, a wafer is subjected to processes such as a
thinning treatment, a treatment at high temperature. Therefore, the
adhesive layer is required to have both easiness of bonding by
which a support plate and a wafer can easily be bonded and heat
resistance by which a suitable bonding of a wafer and a support
plate is achieved through a process.
[0008] However, in an adhesive layer formed by using an adhesive
composition in the related art such as an adhesive material
disclosed in PTL 1, easiness of bonding and heat resistance are not
sufficient, wafer breakage occurs during bonding or during a
process, and stripping of a wafer from a support plate also occurs
during a process.
[0009] Therefore, development of an adhesive composition capable of
forming an adhesive layer having excellent easiness of bonding and
heat resistance is required.
[0010] The present invention has been made in consideration of the
above problems, an object of the present invention is to provide an
adhesive composition capable of forming an adhesive layer having
excellent easiness of bonding and heat resistance, an adhesive film
obtained by forming an adhesive layer made of the adhesive
composition, and a bonding method using the adhesive
composition.
Solution to Problem
[0011] To solve the above problems, the adhesive composition
according to the present invention is an adhesive composition
containing a block copolymer, and an adhesive layer formed by using
the adhesive composition has a Young's modulus of 0.1 GPa or
greater at 23.degree. C., a storage modulus (G') of
1.5.times.10.sup.5 Pa or less at 220.degree. C., and a loss factor
(tan .sigma.) of 1.3 or less at 220.degree. C.
[0012] In addition, the adhesive film of the present invention is
obtained by forming an adhesive layer made of the adhesive
composition on a film.
[0013] Furthermore, the bonding method according to the present
invention includes a bonding step of bonding a support to a wafer
by using the adhesive composition according to the present
invention.
Advantageous Effects of Invention
[0014] The adhesive composition according to the present invention
contains a block copolymer, and an adhesive layer formed by using
the adhesive composition has a Young's modulus of 0.1 GPa or
greater at 23.degree. C., a storage modulus (G') of
1.5.times.10.sup.5 Pa or less at 220.degree. C., and a loss factor
(tan .sigma.) of 1.3 or less at 220.degree. C., and therefore, it
is possible to provide an adhesive composition capable of forming
an adhesive layer having excellent easiness of bonding and heat
resistance.
DESCRIPTION OF EMBODIMENTS
[0015] Hereinafter, embodiments of the present invention will be
described in detail.
[0016] [Adhesive Composition]
[0017] The adhesive composition according to the present invention
is a adhesive composition containing a block copolymer, and an
adhesive layer formed by using the adhesive composition has a
Young's modulus of 0.1 GPa or greater at 23.degree. C., a storage
modulus (G') of 1.5.times.10.sup.5 Pa or less at 220.degree. C.,
and a loss factor (tan .sigma.) of 1.3 or less at 220.degree.
C.
[0018] (Block Copolymer)
[0019] The block copolymer included in the adhesive composition
according to the present invention is a polymer in which two or
more kinds of block portions in which monomer units are
continuously bonded are bound, and is also referred to as a block
copolymer.
[0020] As the block copolymer, various block copolymers can be
used, and for example, a styrene-isoprene-styrene block copolymer
(SIS), a styrene-butadiene-styrene block copolymer (SBS), a
styrene-butadiene-butylene-styrene block copolymer (SBBS), a
styrene-ethylene-butylene-styrene block copolymer (SEBS), a
styrene-ethylene-propylene-styrene block copolymer
(styrene-isoprene-styrene block copolymer) (SEPS), a
styrene-ethylene-ethylene-propylene-styrene block copolymer
(SEEPS), a styrene-ethylene-ethylene-propylene-styrene block
copolymer (Septon V9461 (manufactured by Kuraray Co., Ltd.) or
Septon V9475 (manufactured by Kuraray Co., Ltd.)) of which the
styrene block is a reaction crosslinking type, or a
styrene-ethylene-butylene-styrene block copolymer (having a
reactive polystyrene-based hard block, Septon V9827 (manufactured
by Kuraray Co., Ltd.)) of which the styrene block is a reaction
crosslinking type can be used.
[0021] At least one functional group-containing atomic group may be
bonded to the block copolymer according to the present invention.
For example, the block copolymer can be obtained by bonding at
least one functional group-containing atomic group to a known block
copolymer by using a modifying agent.
[0022] The functional group-containing atomic group is anatomic
group including one or more functional groups. Examples of the
functional groups included in the functional group-containing
atomic group of the present invention include an amino group, an
acid anhydride group (preferably, a maleic anhydride group), an
imido group, a urethane group, an epoxy group, an imino group, a
hydroxyl group, a carboxyl group, a silanol group, and an
alkoxysilane group (the alkoxy group has preferably 1 to 6 carbon
atoms). In the present invention, the block copolymer is an
elastomer, and has a functional group that results in polarity. In
the present invention, by containing a block copolymer having at
least one functional group-containing atomic group, flexibility and
adhesiveness of the adhesive composition are improved.
[0023] As the block copolymer, a diblock copolymer or a triblock
copolymer is preferable, and a triblock copolymer is more
preferable. In addition, a diblock copolymer and a triblock
copolymer may be used in combination. Thus, it is possible to make
the loss factor (tan .sigma.) at 220.degree. C. of an adhesive
layer formed by using the adhesive composition described below be
an optimal value of 1.3 or less.
[0024] In addition, the block copolymer preferably contains a
styrene group, and both terminals of the main chain are preferably
styrene groups. This is because higher heat resistance is exhibited
by blocking styrene having high heat stability at both terminals
thereof. Moreover, the "styrene group" may have a substituent.
Examples of the substituent include an alkyl group having 1 to 5
carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an
alkoxyalkyl group having 1 to 5 carbon atoms, an acetoxy group, and
a carboxyl group.
[0025] The styrene group content of the block copolymer is
preferably 10% by weight to 65% by weight, and more preferably 13%
by weight to 45% by weight. Thus, it is possible to make the
Young's modulus at 23.degree. C. of an adhesive layer formed by
using the adhesive composition described below be an optimal value
of 0.1 GPa or greater.
[0026] Furthermore, the weight average molecular weight of the
block copolymer is preferably 50,000 to 150,000, and more
preferably 60,000 to 120,000. Thus, it is possible to make the
storage modulus (G') at 220.degree. C. of an adhesive layer formed
by using the adhesive composition described below be an optimal
value of 1.5.times.10.sup.5 Pa or less.
[0027] In addition, in a case where the styrene group content of
the block copolymer is in a range of 13% by weight to 50% by weight
and the weight average molecular weight of the block copolymer is
in a range of 50,000 to 150,000, solubility in hydrocarbon-based
solvents is excellent, and thus it is more preferable. Thus, when
removing an adhesive layer formed by the adhesive composition, it
is possible to easily and quickly remove using a hydrocarbon-based
solvent.
[0028] Furthermore, the block copolymer is more preferably a
hydrogenated product. In a case where the block copolymer is a
hydrogenated product, stability with respect to heat is further
improved, and changes in quality such as decomposition and
polymerization are less likely to occur. In addition, the
hydrogenated product is more preferable from the viewpoint of
solubility in hydrocarbon-based solvents and resistance to resist
solvents.
[0029] In addition, the block copolymer preferably includes a unit
of which a glass transition temperature is 23.degree. C. or lower.
In a case where the block copolymer includes a unit of which the
glass transition temperature is 23.degree. C. or lower, it is
possible to make the Young's modulus at 23.degree. C. of an
adhesive layer formed by using the adhesive composition described
below be an optimal value of 0.1 GPa or greater.
[0030] Plural kinds of the block copolymer may be used in
combination. In other words, the adhesive composition according to
the present invention may include plural kinds of the block
copolymer. At least one of plural kinds of the block copolymer
preferably includes a styrene group. Furthermore, a case where the
styrene group content in at least one of plural kinds of the block
copolymer is in a range of 10% by weight to 65% by weight, or a
case where the weight average molecular weight of at least one of
plural kinds of the block copolymer is in a range of 50,000 to
150,000 is within the scope of the present invention. In addition,
in the adhesive composition according to the present invention, in
a case of including plural kinds of the block copolymer, as a
result of mixing, the content of a styrene group may be adjusted to
be in the above range.
[0031] The content of the block copolymer with respect to a polymer
included in the adhesive composition according to the present
invention is preferably 15% by weight or greater, and more
preferably 30% by weight or greater. Thus, it is possible to
suitably provide an adhesive composition capable of forming an
adhesive layer having excellent easiness of bonding and heat
resistance.
[0032] (Adhesive Layer Formed by Using Adhesive Composition)
[0033] An adhesive layer formed by using the adhesive composition
according to the present invention has the Young's modulus of 0.1
GPa or greater at 23.degree. C., the storage modulus (G') of
1.5.times.10.sup.5 Pa or less at 220.degree. C., and the loss
factor (tan .sigma.) of 1.3 or less at 220.degree. C.
[0034] The Young's modulus at 23.degree. C. of the adhesive layer
is 0.1 GPa or greater, more preferably 0.15 GPa or greater, and
still more preferably 0.2 GPa or greater. Here, the Young's modulus
of the adhesive layer means an elastic coefficient obtained by
measuring an indentation depth by a load using a known elastic
coefficient measurement apparatus.
[0035] For example, an adhesive layer of which the Young's modulus
at 23.degree. C. is 0.1 GPa or greater can be formed by using an
adhesive composition containing a block copolymer of which the
styrene group content is 10% by weight to 65% by weight. That is,
the Young's modulus of the adhesive layer can be determined by the
styrene group content of the block copolymer included in the
adhesive composition to be formed.
[0036] The storage modulus at 220.degree. C. of the adhesive layer
is preferably 1.5.times.10.sup.5 Pa or less, and more preferably
6.times.10.sup.4 Pa or less. Here, the storage modulus means a
storage modulus measured by a known dynamic viscoelasticity
measurement apparatus when the temperature is raised at a rate of
5.degree. C./min in a temperature range of 50.degree. C. to
250.degree. C., using a sample having a shape of which a thickness
is 1 mm and a diameter is .phi..sub.25 mm, under a shear condition
of a frequency of 1 Hz.
[0037] For example, an adhesive layer of which the storage modulus
at 220.degree. C. is 1.5.times.10.sup.5 Pa or less can be formed by
using an adhesive composition containing a block copolymer of which
the weight average molecular weight is 50,000 to 150,000. That is,
the storage modulus of the adhesive layer can be adjusted by the
weight average molecular weight of the block copolymer included in
the adhesive composition to be formed.
[0038] The loss factor of the adhesive layer is preferably 1.3 or
less, more preferably 1 or less, and still more preferably 0.9 or
less. Here, the loss factor means a loss factor measured using a
known dynamic viscoelasticity measurement apparatus when the
temperature is raised at a rate of 5.degree. C./min in a
temperature range of 50.degree. C. to 250.degree. C. under shear
conditions of a sample shape of which a thickness is 1 mm and a
diameter is .phi.25 mm and a frequency of 1 Hz.
[0039] For example, an adhesive layer of which the loss factor at
220.degree. C. is 1.3 or less can be formed by using an adhesive
composition containing a diblock copolymer, a triblock copolymer,
or a combined compound of these. That is, the loss factor of the
adhesive layer can be determined by the block copolymer included in
the adhesive composition to be formed.
[0040] The adhesive layer formed by using the adhesive composition
according to the present invention has the Young's modulus of 0.1
GPa or greater at 23.degree. C., the storage modulus (G') of
1.5.times.10.sup.5 Pa or less at 220.degree. C., and the loss
factor (tan .sigma.) of 1.3 or less at 220.degree. C., and thus,
easiness of bonding and heat resistance are excellent.
[0041] (Solvent)
[0042] The solvent included in the adhesive composition according
to the present invention is not limited as long as it can dissolve
the block copolymer. For example, a nonpolar hydrocarbon-based
solvent, a polar petroleum-based solvent, or a nonpolar
petroleum-based solvent can be used.
[0043] Preferably, the solvent may include condensed polycyclic
hydrocarbon. The condensed polycyclic hydrocarbon included in the
solvent can prevent clouding of the solvent when an adhesive
composition is stored in a liquid form (particularly, at a low
temperature). This can improve product stability.
[0044] The hydrocarbon-based solvent can be linear, branched, or
cyclic hydrocarbon. Examples of the hydrocarbon-based solvent
include linear hydrocarbons such as hexane, heptane, octane,
nonane, methyloctane, decane, undecane, dodecane and tridecane,
branched hydrocarbons having 3 to 15 carbon atoms; saturated
aliphatic hydrocarbons such as p-mentane, o-mentane, m-mentane,
diphenyl mentane, 1,4-terpine, 1,8-terpine, bornane, norbornane,
pinane, thujane, carane, and longifolene, .alpha.-terpinene,
.beta.-terpinene, .gamma.-terpinene, .alpha.-pinene, .beta.-pinene,
.alpha.-thujone, .beta.-thujone, and the like.
[0045] Examples of the petroleum-based solvent include cyclohexane,
cycloheptane, cyclooctane, naphthalene, decahydronaphthalene,
tetrahydronaphthalene, and the like.
[0046] In addition, the condensed polycyclic hydrocarbon is a
hydrocarbon consisting of condensed rings in which two or more
monocycles are bonded with each other by sharing only one side
thereof, and a hydrocarbon formed by condensation of two monocycles
is preferably used.
[0047] Examples of the hydrocarbon include a hydrocarbon in which a
five-membered ring and a six-membered ring are combined with each
other and a hydrocarbon in which two six-membered rings are
combined with each other. Examples of the hydrocarbon in which a
five-membered ring and a six-membered ring are combined with each
other include indene, pentalene, indane, and tetrahydroindene, and
examples of the hydrocarbon in which two six-membered rings are
combined with each other include naphthalene, tetrahydronaphthalene
(tetralin), and decahydronaphthalene (decalin).
[0048] In addition, in a case where the solvent contains the
condensed polycyclic hydrocarbon, the component included in the
solvent may be only the condensed polycyclic hydrocarbon, or may
include other components such as a saturated aliphatic hydrocarbon.
In either case, the content of the condensed polycyclic hydrocarbon
is preferably 40 parts by weight or more and more preferably 60
parts by weight or more with respect to the weight of the entire
hydrocarbon solvent. In a case where the content of the condensed
polycyclic hydrocarbon is 40 parts by weight or more with respect
to the weight of the entire hydrocarbon solvent, it is possible to
obtain a high solubility for the resin. In a case where a mixing
ratio of the condensed polycyclic hydrocarbon and the saturated
aliphatic hydrocarbon is controlled within either of the above
content ranges, it is possible to moderate the odor of the
condensed polycyclic hydrocarbon.
[0049] Moreover, the content of a solvent in the adhesive
composition of the present invention is suitably adjusted according
to a thickness of the adhesive layer which is formed by using the
adhesive composition, and for example, when the total amount of the
adhesive composition is 100 parts by weight, it is preferable that
the content of a solvent be in a range of 20 parts by weight to 90
parts by weight. In a case where the content of a solvent is in the
above range, it is possible to easily perform viscosity
adjustment.
[0050] (Thermal Polymerization Inhibitor)
[0051] In the present invention, the adhesive composition may
contain a thermal polymerization inhibitor. The thermal
polymerization inhibitor has a function to prevent a radical
polymerization reaction by heating. Specifically, since the thermal
polymerization inhibitor has a high reactivity with respect to a
radical, the thermal polymerization inhibitor reacts preferentially
with radicals than with monomers, thereby inhibiting polymerization
of the monomers. Therefore, in the adhesive composition including
such a thermal polymerization inhibitor, a polymerization reaction
is suppressed under a high temperature condition (particularly, at
a temperature range 250.degree. C. to 350.degree. C.).
[0052] In a manufacturing process of a semiconductor, for example,
there is a high-temperature process in which a wafer to which a
support plate (support) is adhered is heated at a temperature of
250.degree. C. for 1 hour. If a polymerization reaction occurs in
the adhesive composition by the high temperature during the high
temperature process, solubility of the adhesive composition with
respect to a stripping solution which is used to strip the support
plate from the wafer after the high temperature process is
decreased, and it is not possible to favorably strip the support
plate from the wafer. However, in the adhesive composition of the
present invention containing the thermal polymerization inhibitor,
oxidation by heat and a polymerization reaction caused by the
oxidation are suppressed, and thus, even after the high temperature
process, it is still possible to easily strip the support plate,
and it is possible to suppress generation of residue.
[0053] The thermal polymerization inhibitor is not particularly
limited as long as it is effective in preventing a radical
polymerization reaction by heat, and the thermal polymerization
inhibitor is preferably a thermal polymerization inhibitor having
phenol. By using the thermal polymerization inhibitor containing
phenol, it is possible to secure a favorable solubility even after
the high temperature treatment is performed in ordinary atmosphere.
As the thermal polymerization inhibitor, a hindered phenol-based
antioxidant can be used, and examples thereof include pyrogallol,
benzoquinone, hydroquinone, methylene blue, tert-butylcatechol,
monobenzyl ether, methylhydroquinone, amylquinone,
amyloxyhydroquinone, n-butylphenol, phenol, hydroquinone monopropyl
ether, 4,4'-(1-methylethylidene)bis(2-methylphenol),
4,4'-(1-methylethylidene)bis(2,6-dimethylphenol),
4,4'-[1-[4-(1-(4-hydroxyphenyl)-1-methylethyl)phenyl]ethylidene]bisphenol-
, 4,4',4''-ethylidenetris(2-methylphenol),
4,4',4''-ethylidenetrisphenol,
1,1,3-tris(2,5-dimethyl-4-hydroxyphenyl)-3-phenylpropane,
2,6-di-tert-butyl-4-methylphenol,
2,2'-methylenebis(4-methyl-6-tert-butylphenol),
4,4'-butylidenebis(3-methyl-6-tert-butylphenol),
4,4'-thiobis(3-methyl-6-tert-butylphenol),
3,9-bis[2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionyloxy)-1,1-di-
methylethyl]-2,4,8,10-tetraoxaspiro(5,5)undecane,
triethyleneglycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate-
, n-octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,
penta-erythryl-tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]
(product name: IRGANOX1010, manufactured by Chiba JAPAN Co., Ltd.),
tris(3,5-di-tert-butylhydroxybenzil)isocyanurate, and
thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].
The thermal polymerization inhibitor may be used alone, or two or
more kinds may be used in combination.
[0054] The content of the thermal polymerization inhibitor is
suitably determined according to a type of a block copolymer, use
of the adhesive composition, and an environment in which the
adhesive composition is used, and for example, if the block
copolymer is 100 parts by weight, the content of the thermal
polymerization inhibitor is preferably 0.1 part by weight to 10
parts by weight. In a case where the content of the thermal
polymerization inhibitor is in the above range, an effect
suppressing a polymerization by heat is favorably exhibited, and
decrease in solubility of the adhesive composition with respect to
a stripping solution can be further suppressed after the
high-temperature process.
[0055] (Entrainer)
[0056] The adhesive composition according the present invention may
contain an entrainer which dissolves the thermal polymerization
inhibitor and has a composition different from a composition of a
solvent for dissolving a block polymer. The entrainer is not
particularly limited, and an organic solvent which dissolves
components included in the adhesive composition can be used.
[0057] For example, the organic solvent may be any one organic
solvent or a combination of two or more organic solvents, provided
that the organic solvent can dissolve the components of the
adhesive composition so as to produce a homogeneous solution.
[0058] A specific example of the organic solvent includes a terpene
solvent including an oxygen atom, a carbonyl group, or an acetoxy
group as a polar group, and examples of the organic solvent include
geraniol, nerol, linalool, citral, citronellol, menthol,
isomenthol, neomenthol, .alpha.-terpineol, .beta.-terpineol,
.gamma.-terpineol, terpinene-1-ol, terpinene-4-ol,
dihydroterpinylacetate, 1,4-cineol, 1,8-cineol, borneol, carvone,
ionone, thujone, or camphor. In addition, examples of the organic
solvent include lactone such as .gamma.-butyrolactone or the like;
ketones such as acetone, methylethylketone, cyclohexanone (CH),
methyl-n-pentylketone, methylisopentylketone, or 2-heptanone;
polyols such as ethyleneglycol, diethyleneglycol, propyleneglycol,
or dipropyleneglycol; compounds having an ester bonding such as
ethyleneglycol monoacetate, diethyleneglycol monoacetate,
propyleneglycol monoacetate, or dipropyleneglycol monoacetate,
monoalkyl ether of the polyalcohol or the compound having the ester
bonding, such as monomethyl ether, monoethyl ether, monopropyl
ether, monobutyl ether, a derivative of a polyalcohol such as
compounds having an ether bonding, such as monophenyl ether (among
these, propyleneglycol monomethyl ether acetate (PGMEA),
propyleneglycol monomethyl ether (PGME) are preferable); cyclic
ethers such as dioxane, esters such as methyl lactate, ethyl
lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl
pyruvate, ethyl pyruvate, methyl methoxypropionate, or ethyl
ethoxypropionate; or an aromatic-based organic solvent such as
anisole, ethylbenzil ether, cresylmethyl ether, diphenyl ether,
dibenzyl ether, phenetol, or butylphenyl ether.
[0059] The content of the entrainer is suitably determined
according to a type of the thermal polymerization inhibitor or the
like, and for example, when the total of a solvent (main solvent)
which dissolves a block polymer and a solvent (entrainer) which
dissolves the thermal polymerization inhibitor is 100 parts by
weight, the content of the entrainer is preferably 1 part by weight
to 50 parts by weight, and more preferably 1 part by weight to 30
parts by weight. In a case where the content of the entrainer is in
the above range, it is possible to sufficiently dissolve the
thermal polymerization inhibitor.
[0060] (Other Components)
[0061] The adhesive composition may further include another
miscible substance within a range not impairing essential features
of the present invention. For example, in the adhesive, various
additives commonly used to improve performance of the adhesive such
as an additive resin, a plasticizer, an adhesion auxiliary agent, a
stabilizer, a colorant, and a surfactant can be further used.
[0062] (Method for Preparing Adhesive Composition)
[0063] A method for preparing the adhesive composition according to
the present invention is not particularly limited and a known
method may be used. For example, the adhesive composition according
to the present invention can be obtained by dissolving a block
copolymer in the main solvent and stirring each composition by
using an existing stirrer.
[0064] In a case where the thermal polymerization inhibitor is
added to the adhesive composition according to the present
invention, it is preferable to add the thermal polymerization
inhibitor which was dissolved in advance in the entrainer to the
adhesive composition of the invention.
[0065] [Use of Adhesive Composition]
[0066] The adhesive composition according to the present invention
is used for adhering a wafer and a support of the wafer.
[0067] For example, the support is a member which supports in a
process of thinning a wafer, and is adhered to the wafer by an
adhesive layer formed by using the adhesive composition according
to the present invention. In the embodiment, for example, the
support is formed of glass or silicon of which the film thickness
is in a range of 500 .mu.m to 1,000 .mu.m.
[0068] Moreover, in the embodiment, the support has a though-hole
penetrating in a thickness direction of the support. By pouring the
solvent which dissolves the adhesive composition in between the
support and the wafer through the through-hole, it is possible to
easily separate the support and the substrate.
[0069] In addition, in another embodiment, a reaction layer in
addition to an adhesive layer may be provided between a support and
a wafer. The reaction layer is changed in quality by absorbing
light irradiated through the support, and by changing the reaction
layer in quality by irradiating light or the like thereto, it is
possible to easily separate the support and the wafer. In this
case, it is preferable to use, as the support, a support having no
through-hole penetrating in a thickness direction of the
support.
[0070] As the light irradiated to the reaction layer, laser lights
such as solid-state lasers including a YAG laser, a ruby laser, a
glass laser, a YVO.sub.4 laser, an LD laser, a fiber laser, and the
like, liquid lasers including a dye laser and the like, gas lasers
including a CO.sub.2 laser, an excimer laser, an Ar laser, a He--Ne
laser, and the like, a semiconductor laser and a free electron
laser, or non-laser lights may be suitably used according to the
wavelength which can be absorbed by the reaction layer. For
example, the wavelength of light to be absorbed by the reaction
layer is a wavelength of 600 nm or less, and it is not limited
thereto.
[0071] The reaction layer may contain, for example, a light
absorbent which is decomposed by light or the like. Examples of the
light absorbent include pigments and dyes such as fine particle
metal powders such as graphite powder, iron, aluminum, copper,
nickel, cobalt, manganese, chrome, zinc and tellurium, metal oxide
powders such as black titanium oxide, carbon black, an aromatic
diamine-based metal complex, an aliphatic diamine-based metal
complex, an aromatic dithiol-based metal complex, a
mercaptophenol-based metal complex, a squarylium-based compound, a
cyanine-based pigment, a methine-based pigment, a
naphthoquinone-based pigment, and an anthraquinone-based pigment.
The reaction layer can be formed by, for example, applying a
mixture of the light absorbent and a binder resin onto the support.
In addition, a resin having a light absorbing group can be
used.
[0072] In addition, the reaction layer may be an inorganic or
organic film formed by a plasma CVD method. For example, as the
inorganic film, a metal film can be used. In addition, as the
organic film, a fluorocarbon film can be used. The reaction film
can be formed on the support by, for example, a plasma CVD
method.
[0073] In addition, the adhesive composition according to the
present invention is suitably used for adhesion of a wafer
subjected to a thinning process after being adhered to a support
and the support. As described above, the support holds the strength
of a wafer when the wafer is thinned. The adhesive composition
according to the present invention is suitably used for adhering
such a wafer and support.
[0074] Furthermore, since the adhesive composition according to the
present invention has a low dynamic viscosity even at high
temperature and does not flow even when supplied for a long period
of time to a high temperature process, by an adhesive layer formed
by using this, a wafer and a support can be easily bonded, and in a
wafer thinning process, flexibility of the adhesive layer does not
become high even at an edge portion of the wafer, and wafer
stripping does not occur.
[0075] In addition, the adhesive composition according to the
present invention is suitably used for adhesion of a wafer exposed
in an environment of 220.degree. C. or higher after being adhered
to a support and the support. Since the adhesive composition
according to the present invention has excellent heat resistance,
the adhesive composition is suitably used for adhesion of a wafer
exposed in an environment of 220.degree. C. or higher after being
adhered to a support and the support.
[0076] Moreover, a method for manufacturing a laminate adhering a
wafer and a support with the adhesive composition according to the
invention, a method for thinning a wafer of the laminate, and a
method for heating the laminate at a temperature of 220.degree. C.
or higher are also within the scope of the present invention.
[0077] [Adhesive Film]
[0078] The adhesive composition according to the present invention
can be adopted in various ways according to the use. For example,
the adhesive composition can be used in a method in which the
adhesive layer is formed by applying the adhesive composition in a
liquid form on a work object such as a semiconductor wafer, or a
method (adhesive film method) in which the adhesive film of the
present invention is bonded to a work object of a semiconductor
wafer and the like. According to the adhesive film method, the
adhesive film of the present invention is prepared in advance by
forming the adhesive layer on a film, such as a flexible film, by
use of the adhesive composition and drying the adhesive film thus
formed.
[0079] The adhesive film according to the present invention thus
includes the adhesive layer which contains an adhesive composition,
on the film.
[0080] The adhesive layer of the adhesive film may be covered with
a protecting film. In this case, the adhesive layer is uncovered by
stripping the protecting film, the adhesive layer thus uncovered is
stacked on the work object, and the film is stripped from the
adhesive layer. In this way, it is possible to easily form the
adhesive layer on the work object.
[0081] Therefore, by using the adhesive film, it is possible to
provide the adhesive layer whose film thickness uniformity and
surface smoothness are excellent as compared with an adhesive layer
formed by applying the adhesive composition directly on the work
object.
[0082] The film thus used in preparation of the adhesive film is
not particularly limited, as long as the film is a release film
which can be stripped from the adhesive layer formed on a film so
as to allow transferring of the adhesive layer from the adhesive
film onto a work surface of the work object such as a protecting
substrate or a wafer. For example, the film can be a flexible film
which is made of a synthetic-resin film containing polyethylene
terephthalate, polyethylene, polypropylene, polycarbonate, or
polyvinyl chloride whose film thickness is in a range of 15 .mu.m
to 125 .mu.m. It is preferable that the film be subjected to a
release process if necessary, so as to make transferring of the
adhesive layer easy.
[0083] The method in which the adhesive layer is formed on the film
may be a method in which the adhesive layer is formed by applying
the adhesive composition of the present invention on the film at a
thickness that will be in a range from 10 .mu.m to 1,000 .mu.m
after drying, in which the adhesive composition of the present
invention may be applied appropriately in consideration of a
desired film thickness and uniformity of the adhesive layer and
application may be performed by using a known method.
[0084] In a case where the protecting film is used, the protecting
film is not limited as long as it can be stripped from the adhesive
layer. For example, it is preferable that the protecting film be a
polyethylene terephthalate film, a polypropylene film, or a
polyethylene film. Further, it is preferable that the protecting
film be subjected to a silicone coating process or a silicon baking
process. This is because the protecting film subjected to the
silicon coating process or the silicon baking process can be easily
stripped from the adhesive layer. A thickness of the protecting
film is preferably, but not particularly limited to, in a range
from 15 .mu.m to 125 .mu.m. This is because it is possible to
secure flexibility of the adhesive film with the protecting
film.
[0085] The method in which the adhesive film is used is not limited
to a particular method. For example, in a case where the protecting
film is used, a thermal compression method can be used. According
to the thermal compression method, the adhesive layer is uncovered
by stripping the protecting film, stacked on the work object, and
thermally compressed on the surface of the work object by moving a
heating roller on the film (a surface opposite to a surface on
which the adhesive layer is formed). After stripping, it is
optional to sequentially reel the protecting film stripped from the
adhesive film in a roll form by using a roller such as a reel
roller. In this case, the protecting film can be stored and
reused.
[0086] Since the adhesive film according to the present invention
has a low dynamic viscosity even at high temperature and does not
flow even when supplied for a long period of time to a high
temperature process, a wafer and a support can be easily bonded,
and in a wafer thinning process, flexibility of the adhesive layer
does not become high even at an edge portion of the wafer, and
wafer stripping does not occur.
[0087] [Bonding Method]
[0088] The bonding method according to the present invention
includes a bonding step of bonding a support to a wafer by using
the adhesive composition according to the present invention. Since
by bonding a wafer and a support using the adhesive composition
according to the present invention, the adhesive composition does
not flow even when supplied for a long period of time to a high
temperature process, by using this, a wafer and a support can be
easily bonded, and bonding failure does not occur.
[0089] In the bonding step, a support may be bonded to a wafer
through an adhesive layer formed in advance using the adhesive
composition according to the present invention. For example, the
adhesive layer can be formed by applying the adhesive composition
on a wafer and baking. The baking temperature and the baking time
of the adhesive composition can be suitably selected according to
the adhesive composition or the like used.
[0090] In addition, in the bonding step, a support can be bonded to
a wafer by heating and pressurizing in a reduced pressure
environment. The temperature, the time, and the pressure when a
support is bonded to a wafer can be suitably selected according to
the adhesive composition or the like used, and for example, the
bonding temperature is in a range of 50.degree. C. to 250.degree.
C., and preferably in a range of 100.degree. C. to 250.degree. C.
The bonding time is in a range of 10 seconds to 15 minutes, and
preferably in a range of 30 seconds to 10 minutes. The bonding
pressure is in a range of 100 kg to 10,000 kg, and preferably in a
range of 1,000 kg to 10,000 kg. In addition, in the bonding step, a
wafer and a support may be bonded in a decompressed state (for
example, 1 Pa or less).
EXAMPLES
Example
Preparation of Adhesive Composition
[0091] 100 parts by weight of H1051 (manufactured by Asahi Kasei
Chemicals Corporation, SEBS: triblock copolymer of
styrene-ethylene/butylene-styrene, styrene content of 42% by
weight, and molecular weight of 78,800) which is a triblock
copolymer was dissolved in 280 parts by weight of
decahydronaphthalene shown in the following chemical formula (I)
which is a main solvent.
##STR00001##
[0092] Next, a solution in which "IRGANOX (product name) 1010"
manufactured by BASF Corporation which is a thermal polymerization
inhibitor was dissolved in butyl acetate was added to 100 parts by
weight of the triblock copolymer such that the thermal
polymerization inhibitor becomes 1 part by weight, and the butyl
acetate becomes 20 parts by weight. Thus, the adhesive composition
of Example 1 was prepared.
[0093] (Evaluation of Physical Properties of Adhesive Layer)
[0094] First, the adhesive composition of Example 1 prepared was
spin-coated on a silicon wafer (12 inches), and the resultant
product was baked at 100.degree. C., 160.degree. C., and
200.degree. C. for 3 minutes respectively, in a hotplate under
atmospheric pressure, thereby forming an adhesive layer (thickness:
50 .mu.m). The Young's modulus of the adhesive layer formed on the
wafer was measured under the conditions of a maximum test load of 5
mN, a load application time of 20 seconds, and a creep time of 5
seconds using a FISCHER SCOPE Hm2000 measurement apparatus
(manufactured by Thermo Fisher Scientific Inc.). The Young's
modulus at 23.degree. C. of the adhesive layer was 0.34 GPa as
shown in Table 1.
[0095] In addition, the adhesive composition of Example 1 prepared
was applied to a polyethylene film treated with a release agent,
and the resultant product was baked at 100.degree. C. and
180.degree. C. for 60 minutes respectively, in an oven under
atmospheric pressure, thereby forming an adhesive layer (thickness:
0.5 mm). The storage modulus (G', unit: Pa) and the loss factor
(tan .sigma.) of the adhesive layer stripped from the polyethylene
film were measured using a dynamic viscoelasticity measurement
apparatus (VAR100, manufactured by Thermo Fisher Scientific Inc.).
The storage modulus (G') and the loss factor (tan .sigma.) at
220.degree. C. were measured under the conditions that the
temperature is raised at a rate of 5.degree. C./min from room
temperature to 220.degree. C. using a sample having a shape of
which a thickness is 1 mm and a diameter is .phi.25 mm, and a
parallel plate of .phi.25 mm, under a shear condition of a
frequency of 1 Hz. As shown in Table 1, the storage modulus at
220.degree. C. was 4.9.times.10.sup.4 Pa, and the loss factor at
220.degree. C. was 0.54.
[0096] (Process Evaluation of Adhesive Layer)
[0097] The adhesive composition of Example 1 prepared was
spin-coated on a silicon wafer (12 inches), and the resultant
product was baked at 100.degree. C., 160.degree. C., and
200.degree. C. for 4 minutes respectively, in a hot plate under
atmospheric pressure, thereby forming an adhesive layer (thickness:
50 .mu.m). The obtained adhesive layer was bonded to a glass
support (12 inches) for 3 minutes under the conditions of
220.degree. C. and 4,000 kg in a reduced pressure environment of 1
Pa or less, thereby a laminate was produced. As shown in Table 1,
in this step, bonding failure to the laminate did not occur
(O).
[0098] <Thinning Process>
[0099] In the produced laminate, the wafer was thinned by being
ground up to 40 .mu.m, and appearance of the wafer after thinning
was observed with a microscope. As a result of the observation, as
shown in Table 1, stripping of the wafer and bonding failure in the
laminate did not occur (O).
[0100] <CVD Process and Curing Process>
[0101] The produced laminate was subjected to a plasma CVD process
at 220.degree. C. for 5 minutes, and a curing process of heating at
220.degree. C. for 3 hours in a nitrogen environment. Moreover, the
CVD process corresponds to a forming step of a thermal oxide film
or a nitride film, and the curing process corresponds to a forming
step of an insulating film such as polyimide.
[0102] Appearance of the wafer after the CVD process and the curing
process was observed with a microscope, and bonding failure
(unadhered portion) which causes a wafer breakage or decrease in a
critical dimension uniformity of the wafer and fluidity of the edge
portion of the adhesive layer were evaluated. The fluidity of the
edge portion was evaluated by observing whether the edge portion of
the adhesive layer was raised on the wafer or the shape of the
adhesive layer of the edge portion was changed. As a result of the
observation, as shown in Table 1, in the laminate, fluidity of the
edge portion did not occur, and stripping of the wafer and bonding
failure did not occur (O).
[0103] In addition, the adhesive compositions of Examples 2 to 16
were prepared in the same manner as in Example 1 using each of the
block copolymers described in Table 1, adhesive layers were formed
in the same manner as in Example 1, and an evaluation of physical
properties and a process evaluation were performed. The results are
shown in Table 1. "E" shown in Table 1 refers to an exponent
(4.9E+04=4.9.times.10.sup.4). In addition, "part(s)" shown in Table
1 refers to "part(s) by weight".
TABLE-US-00001 TABLE 1 CVD Curing Young's Bonding Thinning
evaluation evaluation Block copolymer Random copolymer modulus
evaluation evaluation 220.degree. C., 220.degree. C., Example
(G1726 or diblock) resin (GPa) G' (Pa) Tan .sigma. 220.degree. C.
40 .mu.m Si 5 minutes 3 hours 1 H1051 0.34 4.9E+04 0.54
.largecircle. .largecircle. .largecircle. .largecircle. 2
H1051/G1726 = 5/5 0.2 1.1E+04 1.06 .largecircle. .largecircle.
.largecircle. .largecircle. 3 H1051/G1652 = 8/2 0.25 5.9E+04 0.69
.largecircle. .largecircle. .largecircle. .largecircle. 4
H1043/HG252 = 95/5 1.6 5.4E+04 0.3 .largecircle. .largecircle.
.largecircle. .largecircle. 5 H1043/S4033 = 6/4 1.44 9.9E+04 0.47
.largecircle. .largecircle. .largecircle. .largecircle. 6 H1043 85
parts TOPAS8007 15 parts 1.55 5.2E+04 0.41 .largecircle.
.largecircle. .largecircle. .largecircle. 7 H1043/G1726 = 35/65
0.85 8.0E+03 0.84 .largecircle. .largecircle. .largecircle.
.largecircle. 8 MP-10/HG252 = 6/4 0.12 3.6E+04 0.93 .largecircle.
.largecircle. .largecircle. .largecircle. 9 MP-10/HG252 = 95/5 0.21
6.6E+04 0.91 .largecircle. .largecircle. .largecircle.
.largecircle. 10 S8004 50 parts TOPAS-TM 30 parts/ 0.21 1.1E+04
1.09 .largecircle. .largecircle. .largecircle. .largecircle. A1 20
parts 11 S4033 85 parts A1 15 parts 0.19 1.3E+05 0.59 .largecircle.
.largecircle. .largecircle. .largecircle. 12 S4033 50 parts/ A1 10
parts 0.13 1.7E+04 1.05 .largecircle. .largecircle. .largecircle.
.largecircle. HG252 40 parts 13 V9827 70 parts TOPAS-TM 20 parts/
0.11 1.7E+04 1.16 .largecircle. .largecircle. .largecircle.
.largecircle. A2 10 parts 14 H1051 80 parts TOPAS-TM 20 parts 0.33
1.4E+05 0.7 .largecircle. .largecircle. .largecircle. .largecircle.
15 V9827 50 parts/ TOPAS-TM 15 parts/ 0.1 6.9E+03 1.28
.largecircle. .largecircle. .largecircle. .largecircle. S2002 20
parts A2 15 parts 16 S8004 35 parts A1 50 parts/ 0.28 8.2E+03 1.19
.largecircle. .largecircle. .largecircle. .largecircle. TOPAS8007
15 parts
[0104] <Block Copolymer>
[0105] In Examples 2 to 16, as the block copolymer, H1051
(manufactured by Asahi Kasei Chemicals Corporation, SEBS, triblock
copolymer of styrene-ethylene/butylene-styrene, styrene content of
42% by weight, and molecular weight of 78,800);
[0106] G1726 (manufactured by Kraton performance Polymers Inc.,
SEBS/SEB: combination of triblock copolymer of
styrene-ethylene/butylene-styrene block and diblock copolymer of
styrene-ethylene/butylene, styrene content of 30% by weight,
diblock content of 70% by weight (with respect to the total G1726),
and molecular weight of 51,300);
[0107] G1652 (manufactured by Kraton Performance Polymers Inc,
SEBS: triblock copolymer of styrene-ethylene/butylene-styrene,
styrene content of 30% by weight, and molecular weight of
77,700);
[0108] HG1043 (manufactured by Asahi Kasei Chemicals Corporation,
SEBS: triblock copolymer hydrogenated styrene-based thermoplastic
elastomer of styrene-ethylene/butylene-styrene block, styrene
content of 67% by weight, and molecular weight of 77,000);
[0109] HG252 (manufactured by Kuraray Co., Ltd., SEEPS-OH:
polystyrene-poly(ethylene-ethylene/propylene)block-polystyrene
terminal hydroxyl group modification, styrene content of 28% by
weight, and molecular weight of 67,000);
[0110] S4033 (manufactured by Kuraray Co., Ltd., SEPS:
polystyrene-poly(ethylene/propylene) block-polystyrene, styrene
content of 30% by weight, and molecular weight of 95,000);
[0111] MP-10 (manufactured by Asahi Kasei Chemicals Corporation,
SEBS: triblock copolymer hydrogenated styrene-based thermoplastic
elastomer terminal amino modification of
styrene-ethylene/butylene-styrene block, styrene content of 30% by
weight, and molecular weight of 83,000);
[0112] S8004 (manufactured by Kuraray Co., Ltd., SEBS: triblock
copolymer of polystyrene-poly(ethylene/butylene) block-polystyrene,
styrene content of 31% by weight, and molecular weight of
98,100);
[0113] V9827 (manufactured by Kuraray Co., Ltd., SEBS: styrene
block is a reaction crosslinking type
styrene-ethylene-butylene-styrene block copolymer, styrene content
of 30% by weight, and molecular weight of 90,000); and
[0114] S2002 (manufactured by Kuraray Co., Ltd., SEPS: triblock
copolymer of styrene-isoprene-styrene, styrene content of 30% by
weight, and molecular weight of 53,000), were mixed in weight
ratios shown in Table 1, thereby preparing adhesive
compositions.
[0115] <Random Copolymer>
[0116] Copolymers selected from TOPAS-.TM. (manufactured by
Polyplastics Co., Ltd., cycloolefin copolymer,
norbornene:ethylene=65:35 (weight ratio), molecular weight of
10,100, dispersivity of 2.08);
[0117] A1: copolymer of (styrene/dicyclopentanyl
methacrylate/stearyl methacrylate=20/60/20 (weight ratio),
molecular weight of 10,000); and
[0118] A2: copolymer (styrene/1-adamantyl methacrylate/stearyl
methacrylate=20/60/20 (weight ratio), molecular weight of 10,000),
were mixed in weight ratios shown in Table 1, thereby preparing
adhesive compositions.
[0119] As shown in Table 1, in all the adhesive layers formed using
the adhesive compositions of Examples 2 to 16, the Young's moduli
at 23.degree. C. were 0.1 GPa or greater, the storage moduli (G')
at 220.degree. C. were 1.5.times.10.sup.5 Pa or less, and the loss
factors (tan a) at 220.degree. C. were 1.3 or less.
[0120] In addition, as shown in Table 1, in all the laminates
bonded by the adhesive layers formed using the adhesive
compositions of Examples 2 to 16, bonding failure did not occur
when producing the laminates, and even when the wafer was thinned
by being ground up to 40 .mu.m, stripping of the wafer and bonding
failure did not occur (O). Furthermore, in all of Examples 2 to 16,
after the laminates were subjected to the CVD process and the
curing process, fluidity of the edge portion did not occur, and
stripping of the wafer and bonding failure did not occur (O).
Comparative Example
Preparation of Adhesive Composition
[0121] 100 parts by weight of TOPAS-8007 (manufactured by
Polyplastics Co., Ltd., molecular weight of 95,000, dispersivity of
1.9, copolymer of ethylene:norbornene=35:65 (weight ratio)) which
is a hydrocarbon resin was dissolved in 280 parts by weight of
decahydronaphthalene which is a main solvent. Next, a solution in
which "IRGANOX (product name) 1010" manufactured by BASF
Corporation which is a thermal polymerization inhibitor was
dissolved in butyl acetate was added to 100 parts by weight of the
triblock copolymer such that the thermal polymerization inhibitor
becomes 1 part by weight, and the butyl acetate becomes 20 parts by
weight. In this manner, the adhesive composition of Comparative
Example 1 was prepared.
[0122] (Evaluation of Physical Properties of Adhesive Layer)
[0123] An adhesive layer (thickness: 50 .mu.m) was formed on a
silicon wafer (12 inches) in the same manner as in Example, and the
Young's modulus of the adhesive layer was measured using a FISCHER
SCOPE Hm2000 measurement apparatus (manufactured by Thermo Fisher
Scientific Inc.) in the same manner as in Example. As shown in
Table 2, the Young's modulus of the adhesive layer was 3.4 GPa.
[0124] In addition, an adhesive layer (thickness: 0.5 mm) was
formed on a polyethylene film in the same manner as in Example, and
the storage modulus (G') and the loss factor (tan .sigma.) of the
adhesive layer were measured using a dynamic viscoelasticity
measurement apparatus (VAR100, manufactured by Thermo Fisher
Scientific Inc.) in the same manner as in Example. As shown in
Table 2, the storage modulus (G') at 220.degree. C. thereof was
1.4.times.10.sup.3 Pa, and the loss factor (tan .sigma.) at
220.degree. C. thereof was 5.31.
[0125] (Process Evaluation of Adhesive Layer)
[0126] The prepared adhesive composition was spin-coated on a
silicon wafer (12 inches), and the resultant product was baked at
100.degree. C., 160.degree. C., and 200.degree. C. for 4 minutes
respectively, in a hot plate under atmospheric pressure, thereby
forming an adhesive layer (thickness: 50 .mu.m). Next, under the
conditions of a flow rate of 400 sccm, a pressure of 700 mTorr, a
high-frequency power of 2500 W, and a film-forming temperature of
240.degree. C., by a CVD method using C.sub.4F.sub.8 as a reaction
gas, a fluorocarbon film (thickness: 1 .mu.m) was formed on a glass
support (12 inches, thickness: 700 .mu.m) as a release layer. Then,
the glass support on which a release layer was formed and a wafer
substrate were bonded for 3 minutes through an adhesive layer under
the conditions of 220.degree. C. and 4,000 kg in a reduced pressure
environment of 1 Pa or less, thereby producing a laminate in which
the wafer substrate, the adhesive layer, the release layer, and the
glass support were laminated in this order. As shown in Table 2, at
this step, bonding failure to the laminate did not occur (O).
[0127] <Thinning Process>
[0128] In the produced laminate, when the wafer was thinned by
being ground up to 40 .mu.m in the same manner as in Example, as a
result of the observation with a microscope, as shown in Table 2,
stripping of the wafer and bonding failure in the laminate did not
occur (O).
[0129] <CVD Process and Curing Process>
[0130] After the produced laminate was subjected to a plasma CVD
process at 220.degree. C., and a curing process of heating at
220.degree. C. in a nitrogen environment in the same manner as in
Example, appearance of the wafer was observed with a microscope. As
a result of the observation, as shown in Table 2, the edge portion
flowed, and stripping of the wafer and bonding failure occurred
(X).
[0131] In addition, the adhesive compositions of Comparative
Examples 2 to 5 were prepared in the same manner as in Comparative
Example 1 using each of the resins described in Table 2, then
adhesive layers were formed in the same manner as in Comparative
Example 1, and an evaluation of physical properties and a process
evaluation were performed. The results are shown in Table 2. "E"
shown in Table refers to an exponent
(1.4E+03=1.4.times.10.sup.3).
TABLE-US-00002 TABLE 2 CVD Curing Young's Bonding Thinning
evaluation evaluation Comparative modulus evaluation evaluation
220.degree. C., 220.degree. C., Example Resin (GPa) G' (Pa) Tan
.sigma. 220.degree. C. 40 .mu.m Si 5 minutes 3 hours 1 TOPAS8007
3.4 1.4E+03 5.31 .largecircle. .largecircle. X X 2 A3 4.2 1.1E+03
9.74 .largecircle. .largecircle. X X 3 G1726 0.031 1.3E+03 1.85
.largecircle. X X X 4 G1652 0.062 1.8E+05 0.69 X X .largecircle.
.largecircle. 5 Polystyrene 3.3 1.6E+02 14.4 .largecircle.
.largecircle. X X
[0132] In Comparative Examples 2 to 5, as the resin, using each of
A3 (copolymer of styrene/isobornyl methacrylate/methyl
methacrylate/acrylic acid=70.5/11.3/17.0/1.1 (weight ratio) shown
in Table 2, molecular weight of 75,000), G1726 (manufactured by
Kraton performance Polymers Inc.), G1652 (manufactured by Kraton
performance Polymers Inc.), or polystyrene (molecular weight of
96,400), adhesive compositions were prepared.
[0133] As shown in Table 2, in the adhesive layers formed using the
adhesive compositions including the resins of Comparative Examples
2 to 5, there was no adhesive layer which satisfied all of the
Young's modulus of at 23.degree. C. of 0.1 GPa or greater, the
storage modulus (G') at 220.degree. C. of 1.5.times.10.sup.5 Pa or
less, and the loss factor (tan .sigma.) at 220.degree. C. of 1.3 or
less.
[0134] In Comparative Example 4, a bonding failure occurs at the
time when the laminate was produced. In addition, in Comparative
Examples 4 and 5, after the thinning process, stripping of the
wafer and bonding failure occurred. Furthermore, in Comparative
Examples 1 to 3 and 5, after the CVD process and the curing
process, the edge portion flowed, and stripping of the wafer and
bonding failure occurred.
INDUSTRIAL APPLICABILITY
[0135] The present invention can be suitably used, for example, in
a manufacturing process of a fine semiconductor apparatus.
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