U.S. patent application number 13/396532 was filed with the patent office on 2012-08-16 for film for forming protective layer.
This patent application is currently assigned to NITTO DENKO CORPORATION. Invention is credited to Takeshi Matsumura, Takashi Oda, Naohide Takamoto.
Application Number | 20120208009 13/396532 |
Document ID | / |
Family ID | 46621998 |
Filed Date | 2012-08-16 |
United States Patent
Application |
20120208009 |
Kind Code |
A1 |
Oda; Takashi ; et
al. |
August 16, 2012 |
FILM FOR FORMING PROTECTIVE LAYER
Abstract
The present invention aims to provide a film for forming a
protective layer that is capable of preventing cracks in a low
dielectric material layer of a semiconductor wafer while
suppressing an increase in the number of steps in the manufacture
of a semiconductor device. This object is achieved by a film for
forming a protective layer on a bumped wafer in which a low
dielectric material layer is formed, including a support base, an
adhesive layer, and a thermosetting resin layer, laminated in this
order, wherein the melt viscosity of the thermosetting resin layer
is 1.times.10.sup.2 PaS or more and 2.times.10.sup.4 PaS or less,
and the shear modulus of the adhesive layer is 1.times.10.sup.3 Pa
or more and 2.times.10.sup.6 Pa or less, when the thermosetting
resin layer has a temperature in a range of 50 to 120.degree.
C.
Inventors: |
Oda; Takashi; (Ibaraki-shi,
JP) ; Takamoto; Naohide; (Ibaraki-shi, JP) ;
Matsumura; Takeshi; (Ibaraki-shi, JP) |
Assignee: |
NITTO DENKO CORPORATION
Osaka
JP
|
Family ID: |
46621998 |
Appl. No.: |
13/396532 |
Filed: |
February 14, 2012 |
Current U.S.
Class: |
428/336 ;
428/413 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 21/78 20130101; H01L 2924/0002 20130101; H01L 23/3164
20130101; C09D 171/08 20130101; Y10T 428/31511 20150401; H01L
2924/00 20130101; H01L 23/3114 20130101; Y10T 428/265 20150115;
H01L 23/562 20130101 |
Class at
Publication: |
428/336 ;
428/413 |
International
Class: |
B32B 3/00 20060101
B32B003/00; B32B 27/38 20060101 B32B027/38 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 15, 2011 |
JP |
2011-029879 |
Claims
1. A film for forming a protective layer on a bumped wafer in which
a low dielectric material layer is formed, comprising a support
base, an adhesive layer, and a thermosetting resin layer, laminated
in this order, wherein a melt viscosity of the thermosetting resin
layer is 1.times.10.sup.2 PaS or more and 2.times.10.sup.4 PaS or
less, and the shear modulus of the adhesive layer is
1.times.10.sup.3 Pa or more and 2.times.10.sup.6 Pa or less when a
temperature of the thermosetting resin layer is in a range of 50 to
120.degree. C.
2. The film for forming the protective layer according to claim 1,
wherein a thickness of the thermosetting resin layer is 5 .mu.m or
more and 200 .mu.m or less.
3. The film for forming the protective layer according to claim 1,
wherein the thermosetting resin layer contains an epoxy resin and a
phenol resin, and the adhesive layer contains an acrylic
polymer.
4. The film for forming the protective layer according to claim 2,
wherein the thermosetting resin layer contains an epoxy resin and a
phenol resin, and the adhesive layer contains an acrylic polymer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a film for forming a
protective layer in which a support base, an adhesive layer, and a
thermosetting resin layer are laminated, in this order.
[0003] 2. Description of Related Art
[0004] Conventionally, because the distance between circuits is
becoming shorter as the circuit pattern formed on a semiconductor
chip is becoming finer, the capacitance between adjacent circuits
is becoming greater. A phenomenon occurs according to which a
signal traveling in the circuit becomes slow (signal delay) in
proportion to the increase in capacitance. It has been proposed to
lower the capacitance between circuits by forming a low dielectric
material layer on the circuit using a material having a low
dielectric constant, a so-called low-k material (low dielectric
material).
[0005] Examples of the low dielectric material layer include a
SiO.sub.2 film (relative permittivity k=4.2), a SiOF film (k=3.5 to
3.7), and a SiOC film (k=2.5 to 2.8). Such a low dielectric
material layer is formed on a semiconductor wafer by a plasma CVD
method, for example.
[0006] However, such a low dielectric material layer is very
brittle, and may cause cracks in a dicing step of the semiconductor
process and operational abnormality of the semiconductor element. A
method of removing the low dielectric material layer first using a
laser (laser scribing) and then dicing the material with a blade or
the like has been employed recently (see Japanese Patent
Application Laid-Open No. 2010-093273, for example).
SUMMARY OF THE INVENTION
[0007] There has been a problem with dicing in that the number of
steps increases in such a method because the laser scribing is
performed first, followed by dicing with a blade or the like. Even
when the laser scribing is used, the method has room for
improvement in that it cannot sufficiently reduce the generation of
cracks because the low dielectric material layer is brittle.
[0008] The present invention has been made in view of the
above-described problems, and an object thereof is to provide a
film for forming a protective layer that is capable of preventing
cracks in a low dielectric material layer while suppressing an
increase in the number of steps of manufacture of a semiconductor
device.
[0009] The present inventors made investigations to solve these
problems associated with conventional approaches. As a result, they
found that cracks in the low dielectric material layer can be
prevented while suppressing an increase in the number of steps of
manufacture of a semiconductor device by using a film for forming a
protective layer in which a support base, an adhesive layer, and a
thermosetting resin layer are laminated, in this order, and in
which the temperature at which the melt viscosity of the
thermosetting resin layer falls within a specified range, and the
shear modulus of the adhesive layer falls within a specified range,
exists in a range of 50 to 120.degree. C., in accordance with the
present invention.
[0010] The film for forming a protective layer according to the
present invention is a film for forming a protective layer on a
bumped wafer on which a low dielectric material layer is formed,
including a support base, an adhesive layer, and a thermosetting
resin layer, laminated in this order, wherein the melt viscosity of
the thermosetting resin layer is 1.times.10.sup.2 PaS or more and
2.times.10.sup.4 PaS or less, and the shear modulus of the adhesive
layer is 1.times.10.sup.3 Pa or more and 2.times.10.sup.6 Pa or
less when the thermosetting resin layer has a temperature in a
range of 50 to 120.degree. C.
[0011] The film for forming a protective layer can be used in the
following method of manufacturing a semiconductor device, for
example. A method of manufacturing a semiconductor device is
disclosed, which includes the steps of pasting a film for forming a
protective layer onto a bumped wafer in which a low dielectric
material layer is formed with the thermosetting resin layer serving
as a pasting surface; peeling the support base and the adhesive
layer from the thermosetting resin layer; forming a protective
layer by thermally curing the thermosetting resin layer; and dicing
the bumped wafer and the protective layer together.
[0012] In the film for forming a protective layer according to the
present invention, the low dielectric material layer is reinforced
by the protective layer because the protective layer can be formed
on the low dielectric material layer of the bumped wafer. In
addition, if the bumped wafer is diced together with the protective
layer, because the low dielectric material layer is diced while
reinforced by the protective layer, the generation of cracks in the
low dielectric material layer can be suppressed. Because the low
dielectric material layer is diced while reinforced by the
protective layer, the low dielectric material layer does not have
to be removed in advance by laser scribing or the like. As a
result, an increase in the number of steps can be suppressed.
[0013] Because the melt viscosity of the thermosetting resin layer
is 1.times.10.sup.2 PaS or more and 2.times.10.sup.4 PaS or less,
and the shear modulus of the adhesive layer is 1.times.10.sup.3 Pa
or more 2.times.10.sup.6 Pa or less when the thermosetting resin
layer has a temperature in a range of 50 to 120.degree. C., the
bump can be made to protrude from the thermosetting resin layer
when the film for forming a protective layer is pasted onto the
bumped wafer at a temperature in this range. As a result,
deterioration of connection reliability can be suppressed.
[0014] Because the melt viscosity of the thermosetting resin layer
is 1.times.10.sup.2 PaS or more when the film for forming a
protective layer is pasted onto the bumped wafer at a temperature
in the above-described range, the thermosetting resin layer can be
prevented from being washed away when the film for forming a
protective layer is pasted onto the bumped wafer, and the
protective layer can be more certainly formed. Because the melt
viscosity of the thermosetting resin layer is less than
2.times.10.sup.4 PaS when the film for forming a protective layer
is pasted onto the bumped wafer at a temperature in the
above-described range, the bump can be made to more certainly
protrude from the thermosetting resin layer.
[0015] The thickness of the thermosetting resin layer is preferably
5 .mu.m or more and 200 .mu.m or less. The bumped wafer normally
has a height of the bump of 5 to 200 .mu.m. By making the thickness
of the thermosetting resin layer 200 .mu.m or less, the bump can be
made to more certainly protrude from the thermosetting resin layer
when the film for forming a protective layer is pasted onto the
bumped wafer. By making the thickness of the thermosetting resin
layer 5 .mu.m or more, cracks in the low dielectric material layer
during dicing can certainly be prevented.
[0016] In the above-described configuration, the thermosetting
resin layer preferably contains an epoxy resin and a phenol resin,
and the adhesive layer preferably contains an acrylic polymer. By
making the thermosetting resin layer a layer containing an epoxy
resin and a phenol resin as a base, and the adhesive layer a layer
containing an acrylic polymer as a base, the peeling property
between the thermosetting resin layer and the adhesive layer can be
improved.
[0017] According to the present invention, a film for forming a
protective layer can be provided that is capable of preventing
cracks in a low dielectric material layer while suppressing an
increase in the number of steps of manufacture of a semiconductor
device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a sectional view schematically showing one example
of the film for forming a protective layer according to the present
embodiment;
[0019] FIG. 2 is a sectional view schematically showing one example
of the bumped wafer;
[0020] FIG. 3 is a sectional view schematically showing one example
of a method of manufacturing a semiconductor device according to
the present embodiment;
[0021] FIG. 4 is a sectional view schematically showing one example
of a method of manufacturing a semiconductor device according to
the present embodiment;
[0022] FIG. 5 is a sectional view schematically showing one example
of a method of manufacturing a semiconductor device according to
the present embodiment; and
[0023] FIG. 6 is a sectional view schematically showing one example
of a method of manufacturing a semiconductor device according to
the present embodiment.
DESCRIPTION OF THE REFERENCE NUMERALS
[0024] 2 SEMICONDUCTOR WAFER [0025] 3 BUMPED WAFER [0026] 5
SEMICONDUCTOR CHIP [0027] 6 ADHEREND [0028] 10 FILM FOR FORMING
PROTECTIVE LAYER [0029] 12 SUPPORT BASE [0030] 14 ADHESIVE LAYER
[0031] 16 THERMOSETTING RESIN LAYER [0032] 17 PROTECTIVE LAYER
[0033] 22 DICING BLADE [0034] 41 LOW DIELECTRIC MATERIAL LAYER
[0035] 51 BUMP
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] An embodiment of the present invention is explained by
referring to the drawings. However, the present invention is not
limited to these examples. Parts in the drawings that are not
necessary for the explanation are omitted, and there may be parts
that are shown in magnified or reduced scale to facilitate
explanation. First, the film for forming a protective layer
according to the present embodiment is explained below. FIG. 1 is a
sectional view schematically showing one example of the film for
forming a protective layer according to the present embodiment.
Film for Forming Protective Layer
[0037] As shown in FIG. 1, a film 10 for forming a protective layer
has a configuration in which a support base 12, an adhesive layer
14, and a thermosetting resin layer 16 are laminated, in this
order. The surface of the thermosetting resin layer 16 may be
protected by a separator or the like until it is pasted onto a
wafer.
[0038] A bumped wafer, to which the film 10 for forming a
protective layer is pasted, is explained. FIG. 2 is a sectional
view schematically showing one example of the bumped wafer. As
shown in FIG. 2, a bumped wafer 3 has a semiconductor wafer 2 and
bumps 51 formed on a circuit face side of the semiconductor wafer
2. The bumped wafer 3 has a low dielectric material layer 41 on the
circuit face side of the semiconductor wafer 2.
[0039] The semiconductor wafer 2 is not especially limited as long
as it is a known or common semiconductor wafer, and can be
appropriately selected from semiconductor wafers of various types
of materials. In the present invention, a silicon wafer can be
suitably used as the semiconductor wafer. The thickness of the
semiconductor wafer 2 is 10 to 800 .mu.m for example, and above
all, a semiconductor wafer having a thickness of 20 to 200 .mu.m
can be used. The height of the bump 51 is 5 to 200 .mu.m for
example, and above all, the bump 51 having a height of 10 to 100
.mu.m can be generally used.
[0040] The low dielectric material layer 41 can be formed by using
a material having a low dielectric constant, a so-called low-k
material. Examples thereof include a SiO.sub.2 film (relative
permittivity k=4.2), a SiOF film (k=3.5 to 3.7), and a SiOC film
(k=2.5 to 2.8). The low dielectric material layer 41 is formed on
the semiconductor wafer 2 by a plasma CVD method or the like.
[0041] In the film 10 for forming a protective layer (refer to FIG.
1), the melt viscosity of the thermosetting resin layer 16 is
1.times.10.sup.2 PaS or more and 2.times.10.sup.4 PaS or less, and
the shear modulus of the adhesive layer 14 is 1.times.10.sup.3 Pa
or more and 2.times.10.sup.6 Pa or less when the thermosetting
resin layer has a temperature in a range of 50 to 120.degree. C. In
the film 10 for forming a protective layer (refer to FIG. 1), it is
more preferable that the melt viscosity of the thermosetting resin
layer 16 is 1.times.10.sup.3 PaS or more and 1.times.10.sup.4 PaS
or less, and the shear modulus of the adhesive layer 14 is
1.times.10.sup.4 or more and 2.times.10.sup.6 Pa or less when the
thermosetting resin layer has a temperature in a range of 50 to
120.degree. C. Because the melt viscosity of the thermosetting
resin layer 16 is 1.times.10.sup.2 PaS or more and 2.times.10.sup.4
PaS or less, and the shear modulus of the adhesive layer 14 is
1.times.10.sup.3 Pa or more and 2.times.10.sup.6 Pa or less when
the thermosetting resin layer has a temperature in a range of 50 to
120.degree. C., the bump can be made to protrude from the
thermosetting resin layer 16 when the film 10 for forming a
protective layer is pasted onto the bumped wafer 3. As a result,
deterioration of the connection reliability can be suppressed. The
melt viscosity of the thermosetting resin layer 16 can be
controlled by the ratio of the thermosetting resin to be added, for
example. The melt viscosity of the thermosetting resin layer 16 is
1.times.10.sup.2 PaS or more and 2.times.10.sup.4 PaS or less, and
the shear modulus of the adhesive layer 14 is 1.times.10.sup.3 Pa
or more and 2.times.10.sup.6 Pa or less when the thermosetting
resin layer has a temperature more preferably in a range of 50 to
100.degree. C. and further more preferably in a range of 60 to
90.degree. C.
[0042] Because the melt viscosity of the thermosetting resin layer
16 is 1.times.10.sup.2 PaS or more in the above-described
temperature range when the film 10 for forming a protective layer
is pasted onto the bumped wafer 3 in this temperature range, the
thermosetting resin layer 16 can be prevented from being washed
away when the film 10 for forming a protective layer is pasted onto
the bumped wafer 3, and a protective layer 17 can be certainly
formed. Because the melt viscosity of the thermosetting resin layer
16 is less than 2.times.10.sup.4 PaS in the above-described
temperature range when the film 10 for forming a protective layer
is pasted onto the bumped wafer 3 in this temperature range, the
bump can be made to more certainly protrude from the thermosetting
resin layer 16.
[0043] The melt viscosity of the thermosetting resin layer is a
value measured by a parallel plate method using a rheometer (RS-1
manufactured by Haake GmbH). More in detail, it is a value obtained
by performing the measurement under a condition of a gap of 100
.mu.m, a rotating cone diameter of 20 mm, and a rotational speed of
10 s.sup.-1, at a temperature in the range of room temperature to
250.degree. C.
Thermosetting Resin Layer
[0044] The thermosetting resin layer 16 is pasted onto the surface
where the bumps 51 of the bumped wafer 3 are formed, and is used to
hold and fix the bumped wafer 3 when the backside of the bumped
wafer 3 is ground. The thermosetting resin layer 16 is thermally
cured after being pasted onto the bumped wafer 3 to form the
protective layer 17. The protective layer 17 has a function of
protecting the low dielectric material layer 41 when the bumped
wafer 3 is diced.
[0045] The thermosetting resin layer 16 has a film form. The
thermosetting resin layer 16 is normally in an uncured state
(including a semi-cured state) when it is in a form of the film 10
for forming a protective layer as a product, and is thermally cured
after being pasted onto the bumped wafer 3 (see FIG. 2) (details
are described later).
[0046] The thermosetting resin layer 16 can be constituted as a
resin composition containing at least a thermosetting resin. The
resin composition may contain a thermoplastic resin.
[0047] Examples of the thermosetting resin include an epoxy resin,
a phenol resin, an amino resin, an unsaturated polyester resin, a
polyurethane resin, a silicone resin, and a thermosetting polyimide
resin. The thermosetting resins can be used alone, or two types or
more can be used together. An epoxy resin having a small amount of
ionic impurities that erode the semiconductor element is especially
suitable as the thermosetting resin. Further, a phenol resin can be
suitably used as a curing agent for the epoxy resin. When the
thermosetting resin layer 16 is constituted by including an epoxy
resin and a phenol resin, it is preferable to include an acrylic
polymer in the adhesive layer 14. This is because the peeling
property between the thermosetting resin layer 16 and the adhesive
layer 14 can be improved.
[0048] The epoxy resin is not especially limited, and examples
thereof include bifunctional epoxy resins and polyfunctional epoxy
resins such as a bisphenol A type epoxy resin, a bisphenol F type
epoxy resin, a bisphenol S type epoxy resin, a brominated bisphenol
A type epoxy resin, a hydrogenated bisphenol A type epoxy resin, a
bisphenol AF type epoxy resin, a biphenyl type epoxy resin, a
naphthalene type epoxy resin, a fluorene type epoxy resin, a phenol
novolac type epoxy resin, an ortho-cresol novolac type epoxy resin,
a trishydroxyphenylmethane type epoxy resin, and a
tetraphenylolethane type epoxy resin, a hydantoin type epoxy resin,
a trisglycidylisocyanurate type epoxy resin, and a glycidylamine
type epoxy resin.
[0049] As the epoxy resin, a naphthalene type epoxy resin and a
trishydroxyphenylmethane type epoxy resin are especially preferable
among the examples described above. These epoxy resins can be
suitably used to achieve the desired heat resistance during
reflow.
[0050] The epoxy equivalent of the epoxy resin is preferably 150 to
1000 g/eq, and more preferably 150 to 400 g/eq. By making the epoxy
equivalent of the epoxy resin 150 to 400 g/eq, heat resistance can
be improved more.
[0051] The phenol resin acts as a curing agent for the epoxy resin,
and examples thereof include novolac type phenol resins such as a
phenol novolac resin, a phenol aralkyl resin, a cresol novolac
resin, a tert-butylphenol novolac resin, and a nonylphenol novolac
resin, a resol type phenol resin, and polyoxystyrenes such as
polyparaoxystyrene. The phenol resins can be used alone or two
types or more can be used together. Among these phenol resins, a
phenol novolac resin, a cresol novolac resin, and a phenolaralkyl
resin can be preferably used to achieve the desired heat
resistance.
[0052] The phenol equivalent of the phenol resin is preferably 90
to 300 g/eq, more preferably 100 to 270 g/eq, and further
preferably 150 to 250 g/eq to achieve the desired heat resistance
and the stress relaxation property at a high temperature.
[0053] The phenol resin is suitably compounded in the epoxy resin
so that a hydroxyl group in the phenol resin to 1 equivalent of an
epoxy group in the epoxy resin component becomes 0.5 to 2.0
equivalents. The ratio is more preferably 0.8 to 1.2 equivalents.
When the compounding ratio goes out of this range, sufficient
curing reaction does not proceed, and the characteristics of the
epoxy resin cured substance easily deteriorate.
[0054] A thermal curing accelerating catalyst for an epoxy resin
and a phenol resin may be used in the present invention. The
thermal curing accelerating catalyst is not especially limited, and
the catalyst can be appropriately selected from known thermal
curing accelerating catalysts. The thermal curing accelerating
catalysts can be used alone, or two or more types can be used
together. Examples of the thermal curing accelerating catalyst
include an amine curing accelerator, a phosphorus curing
accelerator, an imidazole curing accelerator, a boron curing
accelerator and a phosphorus-boron curing accelerator.
[0055] The amine curing accelerator is not especially limited, and
examples thereof include monoethanolamine trifluoroborate
manufactured by Stella Chemifa and dicyandiamide manufactured by
Nacalai Tesque.
[0056] The phosphorus curing accelerator is not especially limited,
and examples thereof include triorganophosphines such as
triphenylphosphine, tributylphosphine,
tri(p-methylphenyl)phosphine, tri(nonylphenyl)phosphine, and
diphenyltriphosphine, tetraphenyl phosphonium bromide (trade name
TPP-PB), methyltriphenylphosphonium (trade name TPP-MB),
methyltriphosphonium chloride (trade name TPP-MC),
methoxymethyltriphenylphosphonium (trade name TPP-MOC), and
benzyltriphenylphosphonium chloride (trade name TPP-ZC) (all are
manufactured by Hokko Chemical Industry Co., Ltd.). A
triphenylphosphine compound substantially showing insolubility in
the epoxy resin is preferable. When the triphenylphosphine compound
is insoluble in the epoxy resin, excessive thermal curing can be
suppressed. Examples of a thermosetting catalyst having substantial
insolubility in the epoxy resin include methyltriphenylphosphonium
(trade name TPP-MB). Here, "insolubility" designates that the
thermosetting catalyst made of the triphenylphosphine compound is
insoluble in a solvent made of an epoxy resin; and in more detail,
it designates that the thermoset catalyst does not dissolve in an
amount of 10% by weight or more in a temperature range of 10 to
40.degree. C.
[0057] Examples of the imidazole curing accelerator include
2-methylimidazole (trade name 2MZ), 2-undecylimidazole (trade name
C11-Z), 2-heptadecylimidazole (trade name C17Z),
1,2-dimethylimidazole (trade name 1.2DMZ),
2-ethyl-4-methylimidazole (trade name 2E4MZ), 2-phenylimidazole
(trade name 2PZ), 2-phenyl-4-methylimidazole (trade name 2P4MZ),
1-benzyl-2-methylimidazole (trade name 1B2MZ),
1-benzyl-2-phenylimidazole (trade name 1B2PZ),
1-cyanoethyl-2-methylimidazole (trade name 2MZ-CN),
1-cyanoethyl-2-undecylimidazole (trade name C11Z-CN),
1-cyanoethyl-2-phenylimidazolium trimellitate (trade name
2PZCNS-PW),
2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (trade
name 2MZ-A),
2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine (trade
name C11Z-A),
2,4-diamino-6-['-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine
(trade name 2E4MZ-A),
2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine
isocyanuric acid adduct (trade name 2MA-OK),
2-phenyl-4,5-dihydroxymethylimidazole (trade name 2PHZ-PW), and
2-phenyl-4-methyl-5-dihydroxymethylimidazole (trade name 2P4
MHZ-PW) (all are manufactured by Shikoku Chemicals
Corporation).
[0058] The boron curing accelerator is not especially limited, and
examples thereof include trichloroborane.
[0059] The phosphorous-boron curing accelerator is not especially
limited, and examples thereof include tetraphenylphosphonium
tetraphenylborate (trade name TPP-K), tetraphenylphosphonium
tetra-p-triborate (trade name TPP-MK), benzyltriphenylphosphonium
tetraphenylborate (trade name TPP-ZK), and triphenylphosphine
triphenylborane (trade name TPP-S) (all are manufactured by Hokko
Chemical Industry, Co., Ltd.).
[0060] The ratio of the thermal curing-accelerating catalyst is
preferably 0.01% by weight or more and 10% by weight or less, of
the total amount of the thermosetting resin. By making the ratio of
the thermal curing-accelerating catalyst 0.01% by weight or more,
sufficient curing can be achieved. By making the ratio of the
thermal curing-accelerating catalyst 10% by weight or less, the
manufacturing cost can be reduced. The ratio of the thermal
curing-accelerating catalyst is more preferably 0.1% by weight or
more and 5% by weight or less, and further preferably 0.3% by
weight or more and 3% by weight or less, of the total amount of the
thermosetting resin.
[0061] The thermosetting resin layer 16 may be crosslinked to a
certain level in advance to improve the adhesion characteristics to
the bumped wafer 3 under a high temperature and to improve heat
resistance. The thermosetting resin layer 16 can be crosslinked by
adding, as a crosslinking agent, a polyfunctional compound that
reacts with a functional group or the like at the end of the
molecular chain of the polymer during manufacture.
[0062] The crosslinking agent is not especially limited, and a
known crosslinking agent can be used. Specific examples thereof
include an isocyanate crosslinking agent, an epoxy crosslinking
agent, a melamine crosslinking agent, a peroxide crosslinking
agent, a urea crosslinking agent, a metal alkoxide crosslinking
agent, a metal chelate crosslinking agent, a metal salt
crosslinking agent, a carbodiimide crosslinking agent, an oxazoline
crosslinking agent, an aziridine crosslinking agent, and an amine
crosslinking agent. An isocyanate crosslinking agent and an epoxy
crosslinking agent are preferable. The crosslinking agents can be
used alone or two type or more can be used together.
[0063] Examples of the isocyanate crosslinking agent include lower
aliphatic polyisocyanates such as 1,2-ethylene diisocyanate,
1,4-butylene isocyanate, and 1,6-hexamethylene diisocyanate;
alicyclic polyisocyanates such as cyclopentylene diisocyanate,
cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated
tolylene diisocyanate, and hydrogenated xylene diisocyanate; and
aromatic polyisocyanates such as 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and
xylylene diisiocyanate. A trimethylolpropane/tolylene diisocyanate
trimer adduct (tradename: Coronate L manufactured by Nippon
Polyurethane Industry Co., Ltd.) and a
trimethylolpropane/hexamethylene diisocyanate trimer adduct
(tradename: Coronate HL manufactured by Nippon Polyurethane
Industry Co., Ltd.) can also be used. Examples of the epoxy
crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine,
diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane,
1,6-hexanediol diglycidylether, neopentylglycol diglycidylether,
ethyleneglycol diglycidylether, propyleneglycol diglycidylether,
polyethyleneglycol diglycidylether, polypropyleneglycol
diglycidylether, sorbitol polyglycidylether, glycerol
polyglycidylether, pentaerythritol polyglycidylether, polyglycerol
polyglycidylether, sorbitan polyglycidylether, trimethylolpropane
polyglycidylether, diglycidyl adipate, diglycidyl o-phthalate,
triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcin
diglycidylether, bisphenol-s-diglycidyl ether, and an epoxy resin
having two or more epoxy groups in the molecule.
[0064] The amount of the crosslinking agent used is not especially
limited, and can be appropriately selected according to the level
of crosslinking. Specifically, the amount of the crosslinking agent
used is normally preferably 7 parts by weight or less (0.05 to 7
parts by weight, for example) per 100 parts by weight of a polymer
component (especially, a polymer having a functional group at the
end of the molecular chain) for example. By making the amount of
the crosslinking agent used 7 parts by weight or less per 100 parts
by weight of the polymer component, a decrease in adhesive strength
can be suppressed. To improve cohesive strength, the amount of the
crosslinking agent used is preferably 0.05 parts by weight or more
to 100 parts by weight of the polymer component.
[0065] In the present invention, it is possible to perform a
crosslinking treatment by irradiation with an electron beam, an
ultraviolet ray, or the like in place of using the crosslinking
agent or together with the crosslinking agent.
[0066] Examples of the thermoplastic resin include a natural
rubber, a butyl rubber, an isoprene rubber, a chloroprene rubber,
an ethylene-vinyl acetate copolymer, an ethylene-acrylate
copolymer, an ethylene-acrylic ester copolymer, a polybutadiene
resin, a polycarbonate resin, a thermoplastic polyimide resin,
polyamide resins such as 6-nylon and 6,6-nylon, a phenoxy resin, an
acrylic resin, saturated polyester resins such as PET (polyethylene
terephthalate) and PBT (polybutylene terephthalate), a
polyamideimide resin, and a fluororesin. The thermoplastic resins
can be used alone or two types or more can be used together. Of
these thermoplastic resins, acrylic resin is particularly
preferable since the resin contains ionic impurities in only a
small amount and has a high heat resistance so as to make it
possible to ensure the reliability of the semiconductor
element.
[0067] The acrylic resin is not especially limited, and examples
thereof include a polymer having one type or two types or more of
acrylates or methacrylates having a linear or branched alkyl group
having 30 or less carbon atoms (preferably 4 to 18 carbon atoms,
further preferably 6 to 10 carbon atoms, and especially preferably
8 or 9 carbon atoms) as a component. That is, the acrylic resin of
the present invention has a broad meaning and also includes a
methacrylic resin. Examples of the alkyl group include a methyl
group, an ethyl group, a propyl group, an isopropyl group, an
n-butyl group, a t-butyl group, an isobutyl group, a pentyl group,
an isopentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl
group, an octyl group, an isooctyl group, a nonyl group, an
isononyl group, a decyl group, an isodecyl group, an undecyl group,
a dodecyl group (a lauryl group), a tridecyl group, a tetradecyl
group, a stearyl group, and an octadecyl group.
[0068] Other monomers that can form the above-described acrylic
resin (monomers other than an alkylester of acrylic acid or
methacrylic acid having an alkyl group having 30 or less carbon
atoms) are not especially limited. Examples thereof include
carboxyl-containing monomers such as acrylic acid, methacrylic
acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid,
maleic acid, fumaric acid, and crotonic acid; acid anhydride
monomers such as maleic anhydride and itaconic anhydride;
hydroxyl-containing monomers such as 2-hydroxyethyl(meth)acrylate,
2-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate,
6-hydroxyhexyl(meth)acrylate, 8-hydroxyoctyl(meth)acrylate,
10-hydroxydecyl(meth)acrylate, 12-hydroxylauryl(meth)acrylate, and
(4-hydroxymethylcyclohexyl)methylacrylate; monomers which contain a
sulfonic acid group, such as styrenesulfonic acid, allylsulfonic
acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid,
(meth)acrylamidepropane sulfonic acid, sulfopropyl(meth)acrylate,
and (meth)acryloyloxynaphthalenesulfonic acid; and monomers which
contain a phosphoric acid group, such as 2-hydroxyethylacryloyl
phosphate. Among these, a carboxyl group-containing monomer is
preferable in that the preferred value for the tensile storage
modulus, Ea, of the die bond film can be achieved. (Meth)acrylate
refers to an acrylate and/or a methacrylate, and hereinafter, every
occurrence of (meth) in the present application has the same
meaning.
[0069] Other additives can be appropriately compounded in the
thermosetting resin layer 16 as necessary. Examples of the other
additives include a filler, a flame retardant, a silane coupling
agent, an ion trapping agent, an extender, an anti-aging agent, an
antioxidant, and a surfactant.
[0070] The filler may be any of an inorganic filler and an organic
filler. However, an inorganic filler is preferable. By compounding
a filler such as an inorganic filler, resistance to thermal stress
can be improved. Examples of the inorganic filler include ceramics
such as silica, clay, gypsum, calcium carbonate, barium sulfate,
aluminum oxide, beryllium oxide, silicon carbide, and silicon
nitride, metals such as aluminum, copper, silver, gold, nickel,
chromium, lead, tin, zinc, palladium, and solder, alloys, and
various inorganic powders consisting of carbon. The fillers may be
used alone or two types or more can be used together. Among these,
silica, especially molten silica is preferable. The average
particle size of the inorganic filler is preferably in a range of
0.1 to 80 .mu.m. The average particle size of the inorganic filler
can be measured with a laser diffraction type particle size
distribution device, for example.
[0071] The compounding amount of the filler (especially, the
inorganic filler) is preferably 80 parts by weight or less (0 to 80
parts by weight), and especially preferably 0 to 70 parts by weight
to 100 parts by weight of the organic resin component.
[0072] Examples of the flame retardant include antimony trioxide,
antimony pentoxide, and a brominated epoxy resin. These can be used
alone or two types or more can be used together. Examples of the
silane coupling agent include
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
glycidoxypropyltrimethoxysilane, and
.gamma.-glycidoxypropylmethyldiethoxysilane. These compounds can be
used alone or two types or more can be used together. Examples of
the ion trapping agent include hydrotalcites and bismuth hydroxide.
These can be used alone or two types or more can be used
together.
[0073] The thermosetting resin layer 16 can be formed by a common
method of preparing a resin composition by mixing a thermosetting
resin such as an epoxy resin, a thermoplastic resin such as an
acrylic resin as necessary, and a solvent and other additives as
necessary and forming the resin composition into a film-like layer.
Specifically, the film-shaped thermosetting resin layer 16 can be
formed by a method of applying the resin composition onto the
adhesive layer 14 or a method of forming a resin layer by applying
the resin composition onto an appropriate separator such as release
paper and transferring (transferring by adhesion) the resin layer
onto the adhesive layer 14, for example. The resin composition may
be a solution or a dispersion liquid.
[0074] In the present invention, because the thermosetting resin
layer is a film-shaped product formed from a resin composition
containing a thermosetting resin, adhesion to the bumped wafer 3
can be effectively exhibited.
[0075] The thickness of the thermosetting resin layer 16 (the total
thickness in the case of a laminated film) through which the bumps
51 can protrude is sufficient when the thermosetting resin layer 16
is pasted onto the bumped wafer 3, and is preferably 2 to 200 more
preferably 2 to 100 .mu.m, and further preferably 5 to 50
.mu.m.
[0076] The thickness of the thermosetting resin layer 16 is
preferably 0.05 to 0.9 times, and more preferably 0.05 to 0.7 times
the height of the bump 51. When the thickness of the thermosetting
resin layer 16 is 0.05 to 0.9 times the height of the bump 51, the
bumps 51 can be made to more certainly protrude from the
thermosetting resin layer 16 when the film 10 for forming a
protective layer is pasted onto the bumped wafer 3.
[0077] The surface of the thermosetting resin layer 16 is
preferably protected by a separator (release liner) (not shown in
the drawings). The separator has a function as a protective
material to protect the thermosetting resin layer 16 until it is
put to practical use. The separator can be used as a support base
when the thermosetting resin layer 16 is transferred onto the
adhesive layer 14. The separator is peeled when the bumped wafer 3
is pasted onto the film 10 for forming a protective layer. Examples
of the separator include polyethylene, polypropylene, plastic films
such as polyethylene terephthalate whose surface is coated with a
remover such as a fluorine remover or a long chain alkylacrylate
remover, and paper. The separator can be formed by a conventionally
known method. The thickness and the like of the separator are not
especially limited.
Adhesive Layer
[0078] The adhesive used to form the adhesive layer 14 is not
especially limited, and a general pressure-sensitive adhesive such
as an acrylic pressure-sensitive adhesive or a rubber
pressure-sensitive adhesive can be used, for example. The
pressure-sensitive adhesive is preferably an acrylic
pressure-sensitive adhesive containing an acrylic polymer as a base
polymer in view of clean washing of electronic components such as a
semiconductor wafer and glass, which are easily damaged by
contamination, with ultrapure water or an organic solvent such as
alcohol.
[0079] Specific examples of the acryl polymers include an acryl
polymer in which acrylate is used as a main monomer component.
Examples of the acrylate include alkyl acrylate (for example, a
straight chain or branched chain alkyl ester having 1 to 30 carbon
atoms, and particularly 4 to 18 carbon atoms in the alkyl group
such as methylester, ethylester, propylester, isopropylester,
butylester, isobutylester, sec-butylester, t-butylester,
pentylester, isopentylester, hexylester, heptylester, octylester,
2-ethylhexylester, isooctylester, nonylester, decylester,
isodecylester, undecylester, dodecylester, tridecylester,
tetradecylester, hexadecylester, octadecylester, and eicosylester)
and cycloalkyl acrylate (for example, cyclopentylester,
cyclohexylester, etc.). These monomers may be used alone, or two or
more types may be used in combination. The acrylic polymer may
optionally contain a unit corresponding to a different monomer
component copolymerizable with the above-mentioned alkyl ester of
(meth)acrylic acid or cycloalkyl ester thereof in order to improve
the cohesive force, heat resistance or some other property of the
polymer. Examples of such a monomer component include
carboxyl-containing monomers such as acrylic acid, methacrylic
acid, carboxyethyl(meth)acrylate, carboxypentyl(meth)acrylate,
itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid
anhydride monomers such as maleic anhydride, and itaconic
anhydride; hydroxyl-containing monomers such as
2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,
4-hydroxybutyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate,
8-hydroxyoctyl(meth)acrylate, 10-hydroxydecyl(meth)acrylate,
12-hydroxylauryl(meth)acrylate, and
(4-hydroxylmethylcyclohexyl)methyl(meth)acrylate; sulfonic acid
group containing monomers such as styrenesulfonic acid,
allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic
acid, (meth)acrylamidepropanesulfonic acid,
sulfopropyl(meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic
acid; phosphoric acid group containing monomers such as
2-hydroxyethylacryloyl phosphate; acrylamide; and acrylonitrile.
These copolymerizable monomer components may be used alone or in a
combination of two or more thereof. The amount of the
copolymerizable monomer(s) to be used is preferably 40% or less by
weight of all the monomer components.
[0080] For crosslinking, the acrylic polymer can also contain
multifunctional monomers if necessary as the copolymerizable
monomer component. Such multifunctional monomers include hexanediol
di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate,
(poly)propylene glycol di(meth)acrylate, neopentyl glycol
di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylol
propane tri(meth)acrylate, pentaerythritol tri(meth)acrylate,
dipentaerythritol hexa(meth)acrylate, epoxy(meth)acrylate,
polyester(meth)acrylate, urethane(meth)acrylate etc. These
multifunctional monomers can also be used as a mixture of one or
more thereof. For the desired adhesiveness, etc., the amount of the
multifunctional monomer is preferably 30 wt % or less based on the
total monomer content.
[0081] Preparation of the above acryl polymer can be performed in
an appropriate manner such as solution polymerization, emulsion
polymerization, bulk polymerization, and suspension polymerization
of a mixture of one or two or more kinds of component monomers, for
example. Since the adhesive layer preferably has a composition in
which the content of low molecular weight materials is suppressed
for preventing wafer contamination, and since the adhesive layer,
in which an acryl polymer having a weight-average molecular weight
of 300000 or more, particularly 400000 to 1500000 is a main
component, is preferable for preventing wafer contamination, the
adhesive can be made to have an appropriate cross-linking manner
such as an internal cross-linking manner, an external cross-linking
manner, etc.
[0082] To increase the number-average molecular weight of the base
polymer, such as an acrylic polymer etc., an external crosslinking
agent can be suitably adopted in the adhesive. The external
crosslinking method is specifically a reaction method that involves
adding and reacting a crosslinking agent such as a polyisocyanate
compound, epoxy compound, aziridine compound, melamine crosslinking
agent, urea resin, anhydrous compound, polyamine, or carboxyl
group-containing polymer. When the external crosslinking agent is
used, the amount of the crosslinking agent to be used is determined
according to the base polymer to be crosslinked and applications
thereof as the adhesive. Generally, the crosslinking agent is
preferably incorporated in an amount of about 5 parts by weight or
less based on 100 parts by weight of the base polymer. The lower
limit of the crosslinking agent is preferably 0.1 parts by weight
or more. The adhesive may be blended not only with the components
described above, but also with a wide variety of conventionally
known additives such as a tackifier, and an aging inhibitor, if
necessary.
[0083] The adhesive layer 14 can be formed with an ultraviolet-ray
curable adhesive. The adhesive power of the ultraviolet-ray curable
adhesive can be easily decreased by increasing the degree of
crosslinking through irradiation with an ultraviolet ray.
Therefore, when the adhesive layer 14 is formed with an
ultraviolet-ray curable adhesive, the support base 12 and the
adhesive layer 14 can be peeled from the thermosetting resin layer
16 by decreasing the adhesive strength through irradiation with an
ultraviolet ray after the film 10 for forming a protective layer is
pasted onto the bumped wafer 3.
[0084] The irradiation with an ultraviolet ray is preferably
performed at an ultraviolet-ray intensity of 10 to 1000 mJ/cm.sup.2
and it is more preferably performed at 100 to 500 mJ/cm.sup.2. By
making the ultraviolet-ray intensity 10 mJ/cm.sup.2 or more, the
adhesive layer 14 can be cured sufficiently, and excess adhesion
with the thermosetting resin layer 16 can be prevented. As a
result, the adhesive layer 14 can be favorably peeled from the
thermosetting resin layer 16 at the interface therebetween, and
adhesive residue attached to the thermosetting resin layer 16 from
the adhesive layer 14 can be prevented. On the other hand, by
making the ultraviolet-ray intensity 1000 mJ/cm.sup.2 or less,
deterioration of the film due to the generation of heat can be
suppressed.
[0085] An ultraviolet-ray curable adhesive having an
ultraviolet-ray curable functional group such as a carbon-carbon
double bond and exhibiting adhesion can be used without special
limitation. An example of the ultraviolet-ray curable adhesive is
an addition-type ultraviolet-ray curable adhesive in which
ultraviolet-ray curable monomer components and oligomer components
are compounded in a general pressure-sensitive adhesive such as the
acrylic pressure-sensitive adhesive or the rubber
pressure-sensitive adhesive.
[0086] Examples of the ultraviolet-ray curable monomer component to
be compounded include a urethane oligomer, urethane(meth)acrylate,
trimethylolpropane tri(meth)acrylate, tetramethylolmethane
tetra(meth)acrylate, pentaerythritol tri(meth)acrylate,
pentaerythritol tetra(meth)acrylate, dipentaerythritol
monohydroxypenta(meth)acrylate, dipentaerythritol
hexa(meth)acrylate, and 1,4-butane dioldi(meth)acrylate. Further,
the ultraviolet curable oligomer component includes various types
of oligomers such as urethane-based, polyether-based,
polyester-based, polycarbonate-based, and polybutadiene-based
oligomers, and its molecular weight is appropriately in a range of
about 100 to 30,000. Among these, urethane (meth)acrylate is
preferably compounded to enhance the tip protruding property of the
bump. The compounding amount of the ultraviolet-ray curable monomer
component and the oligomer component can be appropriately
determined to an amount in which the adhesive strength of the
adhesive layer can be decreased depending on the type of the
adhesive layer. Generally, it is for example 5 to 500 parts by
weight, and preferably about 40 to 150 parts by weight based on 100
parts by weight of the base polymer such as an acryl polymer
constituting the adhesive.
[0087] Further, besides the added type ultraviolet curable adhesive
described above, the ultraviolet curable adhesive includes an
internally-crosslinked ultraviolet curable adhesive using an acryl
polymer having a radical reactive carbon-carbon double bond in the
polymer side chain, in the main chain, or at the end of the main
chain as the base polymer. The internally-crosslinked ultraviolet
curable adhesives are preferable because they do not require an
oligomer component or other low molecular weight component, which
most internally-crosslinked ultraviolet curable adhesives do not
contain, and they can form an adhesive layer that has a stable
layer structure, where an oligomer component or other low molecular
weight component does not migrate in the adhesive over time.
[0088] The above-mentioned base polymer, which has a carbon-carbon
double bond, may be any polymer that has a carbon-carbon double
bond and further is viscous. For such a base polymer, a polymer
having an acrylic polymer as a basic skeleton is preferable.
Examples of the basic skeleton of the acrylic polymer include the
acrylic polymers exemplified above.
[0089] The method for introducing a carbon-carbon double bond into
any one of the above-mentioned acrylic polymers is not particularly
limited, and may be selected from various methods. The introduction
of the carbon-carbon double bond into a side chain of the polymer
is easier in molecule design. The method is, for example, a method
of copolymerizing a monomer having a functional group with an
acrylic polymer, and then causing the resultant product to undergo
a condensation or addition reaction with a compound having a
functional group reactive with the above-mentioned functional group
and a carbon-carbon double bond, while preserving the ultraviolet
ray curability of the carbon-carbon double bond.
[0090] Example combinations of these functional groups include a
carboxylic acid group and an epoxy group; a carboxylic acid group
and an aziridine group; and a hydroxyl group and an isocyanate
group. Of these combinations, the combination of a hydroxyl group
and an isocyanate group is preferable for monitoring the extent of
the reaction. If the above-mentioned acrylic polymer, which has a
carbon-carbon double bond, can be produced by the combination of
these functional groups, each of the functional groups may be
present on any one of the acrylic polymer and the above-mentioned
compound. It is preferable, for the case of the above-mentioned
preferred combination, that the acrylic polymer has the hydroxyl
group and the above-mentioned compound has the isocyanate group.
Examples of the isocyanate compound in this case, which has a
carbon-carbon double bond, include methacryloyl isocyanate,
2-methacryloyloxyethyl isocyanate, and
m-isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate. The
acrylic polymer may be an acrylic polymer copolymerized with any
one of the hydroxyl-containing monomers exemplified above, or an
ether compound such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl
vinyl ether or diethylene glycol monovinyl ether.
[0091] The intrinsic type (i.e., self cross-linking)
ultraviolet-ray curable adhesive may be made only of the
above-mentioned base polymer (in particular, the acrylic polymer),
which has a carbon-carbon double bond. However, the above-mentioned
ultraviolet ray curable monomer component or oligomer component may
be incorporated into the base polymer to such an extent that
properties of the adhesive are not deteriorated. The amount of the
ultraviolet ray curable oligomer component or the like is usually
30 parts or less by weight, preferably from 0 to 10 parts by weight
for 100 parts by weight of the base polymer.
[0092] In the case that the ultraviolet-ray curable adhesive is
cured with ultraviolet rays or the like, a photopolymerization
initiator is incorporated into the adhesive. Examples of the
photopolymerization initiator include .alpha.-ketol compounds such
as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone,
.alpha.-hydroxy-.alpha.,.alpha.'-dimethylacetophenone,
2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexyl phenyl
ketone; acetophenone compounds such as methoxyacetophenone,
2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and
2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin
ether compounds such as benzoin ethyl ether, benzoin isopropyl
ether, and anisoin methyl ether; ketal compounds such as benzyl
dimethyl ketal; aromatic sulfonyl chloride compounds such as
2-naphthalenesulfonyl chloride; optically active oxime compounds
such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime;
benzophenone compounds such as benzophenone, benzoylbenzoic acid,
and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone compound such
as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone,
2,4-dimethylthioxanthone, isopropylthioxanthone,
2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and
2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones;
acylphosphonoxides; and acylphosphonates. The amount of the
photopolymerization initiator to be blended is, for example, from
about 0.05 to 20 parts by weight for 100 parts by weight of the
acrylic polymer or the like which constitutes the adhesive as a
base polymer.
[0093] When the adhesive layer 14 is formed with an ultraviolet-ray
curable adhesive, the layer may be irradiated with an ultraviolet
ray in advance to adjust the shear modulus and the melt viscosity.
In this case, an example of the ultraviolet-ray intensity is 10 to
1000 mJ/cm.sup.2.
[0094] When curing inhibition due to oxygen occurs during
irradiation with an ultraviolet ray, it is desirable to block
oxygen (air) from the surface of the adhesive layer 14 by some
method. Examples thereof include a method of performing irradiation
with an ultraviolet ray in a nitrogen gas atmosphere.
[0095] The thickness of the adhesive layer 14 is not especially
limited. However, it is preferably 0.1 times or more and 1.2 times
or less the height of the bump and more preferably 0.5 times or
more and 1.2 times or less the height of the bump in order to more
certainly expose the bumps. The specific thickness of the adhesive
layer 14 is preferably 5 to 300 .mu.m and more preferably 5 to 200
for example.
[0096] The total of the thickness of the support base 12 and the
thickness of the adhesive layer 14 is preferably 20 to 500 .mu.m
and more preferably 40 to 200 .mu.m to achieve the desired peeling
property.
Support Base
[0097] The support base 12 is not especially limited, and a plastic
base such as a plastic film or sheet can be suitably used, for
example. Examples of such a plastic material include olefin resins
such as polyethylene (PE), polypropylene (PP), and an
ethylene-propylene copolymer; copolymers having ethylene as a
monomer component such as an ethylene-vinyl acetate copolymer
(EVA), an ionomer resin, an ethylene-(meth)acrylic acid copolymer,
and an ethylene-(meth)acrylate (random or alternating) copolymer;
polyesters such as polyethylene terephthalate (PET), polyethylene
naphthalate (PEN), and polybutylene terephthalate (PBT); acrylic
resins; polyvinyl chloride (PVC); polyurethane; polycarbonate;
polyphenylene sulfide (PPS); amide resins such as polyamide (nylon)
and wholly aromatic polyamide (aramid); polyetheretherketone
(PEEK); polyimide; polyetherimide; polyvinylidene chloride; ABS
(acrylonitrile-butadiene-styrene copolymer); cellulose resins;
silicone resins; and fluorine resins.
[0098] An example of the material of the support base 12 is a
polymer such as a crosslinked body of the above-described resins.
The above-described plastic film may be unstretched or may be
uniaxially stretched or biaxially stretched as necessary. With the
resin sheet having a heat shrinking property given by a stretching
treatment or the like, the adhesion area of the adhesive layer 14
with the thermosetting resin layer 16 is decreased by
heat-shrinking the support base 12 after the film 10 for forming a
protective layer is pasted onto the bumped wafer 3, and the support
base 12 and the adhesive layer 14 can then be easily peeled from
the thermosetting resin layer 16.
[0099] The surface of the support base 12 can be subjected to a
common surface treatment such as a chemical or physical treatment
such as a chromic acid treatment, ozone exposure, flame exposure,
high voltage shock exposure, or an ionizing radiation treatment, or
a coating treatment by a primer (for example, an adhesive material
described later) to enhance adhesion with the adjacent layer, the
bonding property, and the like.
[0100] The same type or different types of the plastic materials
can be appropriately selected and used as the support base 12, and
several kinds of plastic materials can be blended and used as
necessary. A vapor-deposited layer of a conductive substance made
of metals, alloys, oxides of these, or the like and having a
thickness of about 30 to 500 .ANG. can be formed on the support
base 12 to give an antistatic function. The support base 12 may be
a single layer or may be a plurality of layers of two kinds or
more.
[0101] The thickness of the support base 12 (the total thickness in
case of a laminated body) is not especially limited, and it can be
appropriately selected according to strength, flexibility,
application purpose, and the like. It is preferably 10 to 500 .mu.m
and more preferably 20 to 200
[0102] Various additives such as a coloring agent, a filler, a
plasticizer, an anti-aging agent, an antioxidant, a surfactant, and
a flame retardant may be included in the support base 12 as long as
the effect of the present invention is not damaged.
Method of Manufacturing Film for Forming Protective Layer
[0103] The method of manufacturing the film 10 for forming a
protective layer according to the present embodiment is explained.
First, the support base 12 can be formed by a conventionally known
film forming method. Examples of the film forming method include a
calendering method, a casting method in an organic solvent, an
inflation extrusion method in a closed system, a T-die extrusion
method, a co-extrusion method, and a dry lamination method.
[0104] Next, the adhesive layer 14 is formed by applying an
adhesive composition onto the support base 12 and drying (heating
and crosslinking as necessary) the composition. Examples of the
application method include roll coating, screen coating, and
gravure coating. The adhesive layer 14 may be formed on the support
base 12 by directly applying the adhesive composition onto the
support base 12, or the adhesive layer 14 may be formed by applying
the adhesive composition onto release paper whose surface has been
subjected to a peeling treatment, and then the adhesive layer 14
may be transferred to the support base 12. The adhesive layer 14 is
irradiated with an ultraviolet ray to adjust the shear modulus and
the melt viscosity of the adhesive layer 14 as necessary.
[0105] On the other hand, a coating layer is formed by applying a
material for forming the thermosetting resin layer 16 onto release
paper so that the thickness of the layer after drying becomes a
prescribed thickness, and drying the material under a prescribed
condition (performing a heating treatment for drying as necessary
when heat curing is necessary). The thermosetting resin layer 16 is
formed on the adhesive layer 14 by transferring this coating layer
onto the adhesive layer 14. The thermosetting resin layer 16 can be
formed on the adhesive layer 14 also by applying a material for
forming the thermosetting resin layer 16 directly onto the adhesive
layer 14 and drying the material under a prescribed condition
(performing a heating treatment for drying as necessary when heat
curing is necessary). With this operation, the film 10 for forming
a protective layer can be obtained.
Method of Manufacturing Semiconductor Device
[0106] In the following, the method of manufacturing a
semiconductor device according to the present embodiment is
explained by referring to FIGS. 3 to 6. FIGS. 3 to 6 are sectional
views schematically showing one example of the method of
manufacturing a semiconductor device according to the present
embodiment.
[0107] The method of manufacturing a semiconductor device according
to the present embodiment has at least the steps of pasting the
film 10 for forming a protective layer onto the bumped wafer 3 with
the thermosetting resin layer 16 being a pasting surface, peeling
the support base 12 and the adhesive layer 14 from the
thermosetting resin layer 16, forming the protective layer 17 by
thermally curing the thermosetting resin layer 16, and dicing the
bumped wafer 3 and the protective layer 17 together.
[0108] First, as shown in FIG. 3, the film 10 for forming a
protective layer is pasted onto the bumped wafer 3 with the
thermosetting resin layer 16 being a pasting surface. The pasting
method is not especially limited. However, a pressure-bonding
method is preferable. Pressure-bonding is normally performed by
pressing the laminate with a pressing means such as a pressure
roll. As a pressure-bonding condition, the pressure-bonding
temperature is preferably 25 to 150.degree. C. and more preferably
30 to 100.degree. C. The linear pressure is preferably 0.05 to 1.0
MPa and more preferably 0.2 to 1.0 MPa. The pressure-bonding speed
is preferably 1 to 100 mm/sec and more preferably 10 to 80 mm/sec.
With this operation, the bumps 51 of the bumped wafer 3 protrude
from the thermosetting resin layer 16.
[0109] Next, backside grinding of the bumped wafer 3 is performed
as necessary. Because the film 10 for forming a protective layer is
pasted onto the surface where the bumps 51 of the bumped wafer 3
are formed, the bumped wafer 3 can be held and fixed by the film 10
for forming a protective layer. The backside of the bumped wafer 3
is the surface where the bumps 51 of the bumped wafer 3 are not
formed.
[0110] Next, a dicing tape (not shown in the drawings) is pasted
onto the backside of the bumped wafer 3. A conventionally known
dicing tape can be used, and also a conventionally known pasting
apparatus can be used.
[0111] Then, the support base 12 and the adhesive layer 14 are
peeled from the thermosetting resin layer 16. When the adhesive
layer 14 is made of an ultraviolet-ray curable resin, it is
irradiated with an ultraviolet ray from the support base 12 side as
necessary. With this operation, the adhesive layer 14 is cured, and
the peel strength of the interface between the adhesive layer 14
and the thermosetting resin layer 16 decreases.
[0112] For example, a back grinding tape peeling apparatus
MA-300011 manufactured by Nitto Seiki Co., Ltd. can be used for
peeling. The peel strength of the thermosetting resin layer 16
(before thermal curing) from the adhesive layer 14 is preferably 5
N/20 mm or less (for example, 0.01 N/20 mm to 5 N/20 mm) and more
preferably 0.01 N/20 mm to 1 N/20 mm. By making the peel strength
of the thermosetting resin layer 16 (before thermal curing) from
the adhesive layer 14 within the above-described numerical range,
the thermosetting resin layer 16 (before thermal curing) can be
favorably peeled from the adhesive layer 14. The value of the peel
strength is a value measured by a T-type peeling test (JIS K6854-3)
performed at a temperature of 23.+-.2.degree. C., a peeling angle
of 180.degree., a peeling speed of 300 mm/min, and a distance
between chucks of 100 mm. An Autograph AGS-H (trade name)
manufactured by Shimadzu Corporation is used as a tensile
tester.
[0113] Next, the protective layer 17 is formed by thermally curing
the thermosetting resin layer 16 (see FIG. 4). As a heating
condition, the heating temperature is preferably 120 to 200.degree.
C. and more preferably 140 to 180.degree. C. The heating time is
preferably 30 minutes to 3 hours and more preferably 1 to 2
hours.
[0114] Then, the bumped wafer 3 is diced together with the
protective layer 17 by a dicing blade 22 (see FIG. 5). For dicing,
a conventionally known dicing apparatus having a dicing blade can
be used, for example. Because the low dielectric material layer 41
of the bumped wafer 3 is diced in a state where it is reinforced
with the protective layer 17, the generation of cracks in the low
dielectric material layer 41 can be suppressed. Because the low
dielectric material layer 41 is diced in a state where it is
reinforced with the protective layer 17, the low dielectric
material layer 41 does not have to be removed in advance by laser
scribing or the like. As a result, an increase in the number of
processing steps can be suppressed. However, in the present
invention, the low dielectric material layer on a dicing street is
preferably removed in advance by laser scribing or the like before
dicing (for example, before pasting the bumped wafer to the film
for forming a protective layer). This procedure is preferable in
that cracks in the low dielectric material layer can more certainly
be suppressed.
[0115] After that, as shown in FIG. 6, a semiconductor chip 5
individualized by dicing is picked up, and adhered and fixed to an
adherend 6. Because the bumps 51 on the semiconductor chip 5
protrude from the protective layer 17, they can be electrically
connected to the conductive material 61 on the adherend 6.
Specifically, the semiconductor chip 5 is fixed to the adherend 6
by a conventional method in a state where the bumped surface of the
semiconductor chip 5 faces the adherend 6. For example, the
semiconductor chip 5 can be fixed to the adherend 6, thereby
securing the electrical conduction of the semiconductor chip 5 with
the adherend 6, by melting a conductive material 61 such as solder
while contacting and pressing the bumped surface of the
semiconductor chip 5 to the conductive material adhered to a
connection pad of the adherend 6. At this time, a space is formed
between the semiconductor chip 5 and the adherend 6, and the
distance of the space is generally about 30 to 300 .mu.m. After the
semiconductor chip 5 is adhered onto the adherend 6, the surface of
the semiconductor chip 5 facing the adherend 6 and the space
therebetween are washed, and the space is filled and sealed with a
sealing material such as a sealing resin.
[0116] Various substrates such as a lead frame and a circuit board
(wiring circuit board, or the like) can be used as the adherend 6.
The material of the substrate is not especially limited, and
examples thereof include a ceramic substrate and a plastic
substrate. Examples of the plastic substrate include an epoxy
substrate, a bismaleimide triazine substrate, and a polyimide
substrate.
[0117] The material of the bump and the conductive material is not
especially limited, and examples thereof include solder (alloys) of
a tin-lead metal material, a tin-silver metal material, a
tin-silver-copper metal material, a tin-zinc metal material, and a
tin-zinc-bismuth metal material, a gold metal material, and a
copper metal material.
[0118] In this step, it is preferable to wash the opposing surface
(electrode forming surface) between the semiconductor chip 5 and
the adherend 6 and the space therebetween. The washing liquid used
for washing is not especially limited, and examples thereof include
an organic washing liquid and an aqueous washing liquid.
[0119] Next, a sealing step is performed for sealing the space
between the semiconductor chip 5 and the adherend 6. The sealing
step is performed using a sealing resin. The sealing condition is
not especially limited. Normally, thermal curing of the sealing
resin is performed by heating at 175.degree. C. for 60 to 90
seconds. However, the present invention is not limited to this
operation, and the resin can be cured at 165 to 185.degree. C. for
a few minutes.
[0120] The sealing resin should be understood not to be
particularly limited, and may be a resin having an insulating
property (referred to as an "insulating resin"). Accordingly,
sealing materials such as known sealing resins can be appropriately
selected and used. However, an insulating resin having substantial
elasticity is more preferable. Examples of the sealing resin
include a resin composition containing an epoxy resin. The epoxy
resins exemplified above can be used. In the epoxy-containing
sealing resin, a thermosetting resin other than the epoxy resin
such as a phenol resin, a thermoplastic resin, or the like may be
contained as a resin component besides the epoxy resin. The phenol
resin can be used as a curing agent for the epoxy resin, and
examples of the phenol resin include the phenol resins exemplified
above.
[0121] Below, preferred examples of the present invention are
explained in detail. However, materials, addition amounts, and the
like described in these examples are not intended to limit the
scope of the present invention, and shall be understood merely to
be illustrative examples for the purposes of explanation, and any
limitations specifically described below shall be understood as
example limitations.
<Preparation of Support Base>
[0122] A polyethylene terephthalate film (PET film) having a
thickness of 50 .mu.m and an ethylene vinyl acetate copolymer film
(EVA film) having a thickness of 120 .mu.m were prepared.
<Production of Adhesive Layer>
[0123] In Examples 1 to 9 and Comparative Examples 1 and 2, an
adhesive layer was obtained by applying the following adhesive
composition solution A onto the prepared support base and drying
the solution. The thickness of the produced adhesive layer is as
shown in Tables 1 and 2.
Adhesive Composition Solution A
[0124] 86.4 parts of 2-ethylhexyl acrylate (hereinafter, also
referred to as "2EHA"), 13.6 parts of 2-hydroxyethyl acrylate
(hereinafter, also referred to as "HEA"), 0.2 parts of benzoyl
peroxide, and 65 parts of toluene were charged into a reactor with
a cooling tube, a nitrogen introducing tube, a thermometer, and a
stirrer, and then polymerized at 61.degree. C. in a nitrogen gas
stream for 6 hours to give an acrylic polymer A.
[0125] An acrylic polymer A' was obtained by adding 14.6 parts of
2-methacryloyloxyethyl isocyanate (hereinafter, also referred to as
"MOI") to the acrylic polymer A, and performing an addition
reaction at 50.degree. C. in an air stream for 48 hours.
[0126] Next, an adhesive composition solution A was obtained by
adding 8 parts of a polyisocyanate compound (trade name: Coronate L
manufactured by Nippon Polyurethane Industry Co., Ltd.) and 5 parts
of a photopolymerization initiator (trade name: Irgacure 651
manufactured by Ciba Specialty Chemicals Inc.) into 100 parts of
the acrylic polymer A'.
<Production of Thermosetting Resin Layer>
Thermosetting Resin Layer a
[0127] 31.6 parts of a naphthalene type epoxy resin having an epoxy
equivalent of 142 g/eq (trade name: HP4032D manufactured by DIC
Co., Ltd.), 7.9 parts of a trisphenol meta type epoxy resin having
an epoxy equivalent of 169 g/eq (trade name: EPPN501HY manufactured
by Nippon Kayaku Co., Ltd.), 47.3 parts of an aralkyl type phenol
resin having a phenol equivalent of 175 g/eq (trade name: MEHC7800S
manufactured by Meiwa Plastic Industries, Ltd.), 12 parts of a
butyl acrylate-acrylonitrile-glycidyl methacrylate copolymer (trade
name: SG-28GM manufactured by Nagase ChemteX Corporation), and 1.2
parts of triphenylphosphine as a curing catalyst were dissolved in
methylethylketone to prepare a solution of the adhesive composition
having a solid concentration of 38.6% by weight.
[0128] A thermosetting resin layer a having the thickness shown in
Tables 1 and 2 was produced by applying this solution of the
adhesive composition onto a release film made of a polyethylene
terephthalate film having a thickness of 50 .mu.m, which had been
subjected to a silicone release treatment as a release liner
(separator), and drying the solution at 130.degree. C. for 2
minutes.
Thermosetting Resin Layer b
[0129] 38.1 parts of a trisphenol meta type epoxy resin having an
epoxy equivalent of 169 g/eq (trade name: EPPN501HY manufactured by
Nippon Kayaku Co., Ltd.), 40.8 parts of an aralkyl type phenol
resin having a phenol equivalent of 175 g/eq (trade name: MEHC7800S
manufactured by Meiwa Plastic Industries, Ltd.), 20 parts of a
butyl acrylate-acrylonitrile-ethyl methacrylate copolymer (trade
name: SG-P3 manufactured by Nagase ChemteX Corporation), and 1.2
parts of triphenylphosphine as a curing catalyst were dissolved in
methylethylketone to prepare a solution of the adhesive composition
having a solid concentration of 48.0% by weight.
[0130] A thermosetting resin layer b having the thickness shown in
Tables 1 and 2 was produced by applying this solution of adhesive
composition onto a release film made of a polyethylene
terephthalate film having a thickness of 50 .mu.m which had been
subjected to a silicone release treatment as a release liner
(separator), and drying the solution at 130.degree. C. for 2
minutes.
Thermosetting Resin Layer c
[0131] 34.4 parts of a bisphenol A type epoxy resin having an epoxy
equivalent of 185 g/eq (trade name: YL-980 manufactured by Japan
Epoxy Resin Co., Ltd.), 14.8 parts of a trisphenol meta type epoxy
resin having an epoxy equivalent of 169 g/eq (trade name: EPPN501HY
manufactured by Nippon Kayaku Co., Ltd.), 22.6 parts of an aralkyl
type phenol resin having a phenol equivalent of 175 g/eq (trade
name: MEHC7800S manufactured by Meiwa Plastic Industries, Ltd.),
15.1 parts of a phenol novolac resin having a phenol equivalent of
105 g/eq (trade name: GS-180 manufactured by Gun Ei Chemical
Industry Co., Ltd.), 12 parts of a butyl
acrylate-acrylonitrile-ethyl methacrylate copolymer (trade name:
SG-P3 manufactured by Nagase ChemteX Corporation), and 1.2 parts of
triphenylphosphine as a curing catalyst were dissolved in
methylethylketone to prepare a solution of the adhesive composition
having a solid concentration of 54.4% by weight.
[0132] A thermosetting resin layer c having the thickness shown in
Tables 1 and 2 was produced by applying this solution of adhesive
composition onto a release film made of a polyethylene
terephthalate film having a thickness of 50 .mu.m, which had been
subjected to a silicone release treatment as a release liner
(separator) and drying the solution at 130.degree. C. for 2
minutes.
<Production of Film for Forming Protective Layer>
[0133] In Examples 1 to 9 and Comparative Examples 1 and 2, a film
for forming a protective layer was produced by pasting each of the
thermosetting resin layers produced as described above onto the
adhesive layer produced as described above. In Comparative Examples
3 and 4, a film for forming a protective layer was produced by
pasting each of the thermosetting resin layers produced as
described above onto the prepared support base. Combinations of the
support base, adhesive layer, and thermosetting resin layer of the
films for forming a protective layer according to examples and
comparative examples are shown in Tables 1 and 2.
[0134] The conditions of the lamination step are as follows.
<Laminator Condition>
[0135] Laminator: roll laminator
[0136] Laminating speed: 1 mm/min
[0137] Laminating pressure: 0.5 MPa
[0138] Laminator temperature: room temperature (23.degree. C.)
Measurement of Shear Modulus of Adhesive Layer
[0139] The shear modulus of the adhesive layer (in Examples 3 to 9
and Comparative Examples 1 and 2, the adhesive layer after
irradiation with an ultraviolet ray shown in Tables 1 and 2) was
measured. The shear modulus was measured by forming an adhesive
layer (thickness 0.2 mm) using the prepared adhesive composition
solution A using a shear modulus measurement apparatus (ARES
manufactured by Rheometric Scientific FE, Ltd.) Specifically, the
shear modulus of the sample was measured at the "pasting
temperature" shown in Tables 1 and 2 under a condition of a
frequency of 1 Hz, a plate diameter of 7.9 mm .phi., and a strain
of 1%. The results are shown in Tables 1 and 2.
Measurement of Melt Viscosity
[0140] The melt viscosity of the thermosetting resin layer (before
thermal curing) was measured. The melt viscosity is measured by a
parallel plate method using a rheometer (RS-1 manufactured by Haake
GmbH). In more detail, the measurement is performed using a gap of
100 .mu.m, a rotating cone diameter of 20 mm, and a rotational
speed of 10 s.sup.-1 at a temperature in the range of room
temperature to 250.degree. C. The melt viscosity at the "pasting
temperature" shown in Tables 1 and 2 was regarded as the measured
value. The results are shown in Tables 1 and 2. Peel strength of
adhesive layer and thermosetting resin layer and peeling property
at the interface between adhesive layer and thermosetting resin
layer
[0141] Each of the films for forming a protective layer in the
Examples and Comparative Examples were pasted onto the surface of a
bumped silicon wafer where bumps were formed with the thermosetting
resin layer as the pasting surface. The following wafer was used as
the bumped silicon wafer. The pasting conditions were as
follows.
<Bumped Silicon Wafer>
[0142] Thickness of silicon wafer: 200 .mu.m
[0143] Material of low dielectric material layer: SiN film
[0144] Thickness of low dielectric material layer: 0.3 .mu.m
[0145] Height of bump: 65 .mu.m
[0146] Pitch of bump: 150 .mu.m
[0147] Material of bump: solder
<Pasting Condition>
[0148] Pasting apparatus: DR-3000 .mu.l manufactured by Nitto Seiki
Co., Ltd.
[0149] Laminating speed: 0.1 mm/min
[0150] Laminating pressure: 0.5 MPa
[0151] Laminator temperature: set at the "pasting temperature" in
Tables 1 and 2
[0152] Then, the peel strength of the adhesive layer from the
thermosetting resin layer was measured. Specifically, a T-type
peeling test (JIS K6854-3) as a tensile test was performed at a
temperature of 23.+-.2.degree. C., a peeling angle of 180.degree.,
a peeling speed of 300 mm/min, and a distance between chucks of 100
mm using an Autograph AGS-H (trade name) manufactured by Shimadzu
Corporation. The results are shown in Tables 1 and 2. The adhesive
layer was cured in Examples 1 and 2 by irradiation with an
ultraviolet ray from the support base side. For ultraviolet
irradiation, an ultraviolet ray irradiation apparatus (trade name:
UM810 manufactured by Nitto Seiki Co., Ltd.) was used and the
ultraviolet ray irradiation intensity was set to 400 mJ/cm.sup.2.
After that, the peel strength of the adhesive layer on the
thermosetting resin layer was measured. The results are shown in
Tables 1 and 2 as "peel strength of adhesive layer on thermosetting
resin layer before peeling and after irradiation with ultraviolet
ray."
[0153] The ability to peel the adhesive layer with a support base
from the protective layer (thermosetting resin layer) was
evaluated. The evaluation results are shown in Tables 1 and 2, by
marking cases where the adhesive layer was peeled from the
thermosetting resin layer at the interface as .smallcircle. and
marking cases where it was not peeled as x.
Whether the Tip of Bump is Exposed or not
[0154] The evaluation was performed by observing the surface of the
semiconductor wafer side of the sample used in the peeling test.
The results are shown in Tables 1 and 2, by marking cases where the
tip of the bump was exposed as o and cases where it is not exposed
as x.
Dicing Property
[0155] After observation of the exposure of the tip of the bump, a
protective layer was formed by curing the thermosetting resin layer
by heating at 175.degree. C. for 2 hours. After that, dicing of the
bumped silicon wafer was performed. The bumped silicon wafer was
diced together with the protective layer using DU-300 manufactured
by Nitto Denko Corporation as the dicing tape and DFD6361 (trade
name) manufactured by DISCO Corporation as the dicing apparatus.
The evaluation was performed by marking cases where the dicing was
successful, where there was no peeling or chipping of the low
dielectric material layer, as .smallcircle., and by marking cases
where there was even a little peeling or chipping of the low
dielectric material layer, as x. The results are shown in Tables 1
and 2. However, evaluation of the dicing property was not performed
in Comparative Examples 1 and 3 because the tip of the bump could
not be exposed. Evaluation of the dicing property was not performed
in Comparative Example 4 because the support base could not be
peeled from the protective layer (the thermosetting resin
layer).
<Dicing Condition>
[0156] Dicing size: 10 mm.times.10 mm
[0157] Dicing speed: 30 mm/sec
[0158] Spindle rotating speed: 40000 rpm
TABLE-US-00001 TABLE 1 EXAM- EXAM- EXAM- EXAM- EXAM- EXAM- EXAM-
EXAM- EXAM- PLE 1 PLE 2 PLE 3 PLE 4 PLE 5 PLE 6 PLE 7 PLE 8 PLE 9
PASTING TEMPERATURE (.degree. C.) 75 75 75 75 100 65 75 75 50
SUPPORT MATERIAL PET PET PET PET PET PET PET PET PET BASE THICKNESS
(.mu.m) 50 50 50 50 50 50 50 50 50 ADHE- TYPE OF A A A A A A A A A
SIVE SOLUTION LAYER THICKNESS 30 60 30 60 30 30 30 30 30
ULTRAVIOLET 0 0 400 400 400 400 400 400 400 RAY IRRADIA- TION
INTEN- SITY (mJ/cm.sup.2) SHEAR MODULUS 3.8 .times. 10.sup.4 3.8
.times. 10.sup.4 5.7 .times. 10.sup.5 5.7 .times. 10.sup.5 4.5
.times. 10.sup.4 2.9 .times. 10.sup.5 5.7 .times. 10.sup.5 5.7
.times. 10.sup.5 1.2 .times. 10.sup.6 (Pa) AT PASTING TEMPERATURE
THERMO- TYPE OF a a a a a a a a a SETTING SOLUTION RESIN THICKNESS
(.mu.m) 40 40 40 40 40 40 60 5 40 LAYER MELT VISCOSITY 1.5 .times.
10.sup.3 1.5 .times. 10.sup.3 1.5 .times. 10.sup.3 1.5 .times.
10.sup.3 4.5 .times. 10.sup.2 1.2 .times. 10.sup.4 1.5 .times.
10.sup.3 1.5 .times. 10.sup.3 1.7 .times. 10.sup.4 (Pa S) AT
PASTING TEM- PERATURE INITIAL PEEL STRENGTH (N/20 mm) >2 >2
0.04 0.03 0.04 0.04 0.04 0.04 0.04 OF ADHESIVE LAYER ON THERMO-
SETTING RESIN LAYER IRRADIATION WITH ULTRAVIOLET YES YES NO NO NO
NO NO NO NO RAY BEFORE PEELING PEEL STRENGTH (N/20 mm) OF 0.04 0.04
-- -- -- -- -- -- -- ADHESIVE LAYER ON THERMO- SETTING RESIN LAYER
BEFORE PEELING AND AFTER IRRADIA- TION WITH ULTRAVIOLET RAY PEELING
PROPERTY .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. WHETHER TIP OF BUMP IS EXPOSED .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. OR NOT
THICKNESS RATIO 40/65 40/65 40/65 40/65 40/65 40/65 60/65 5/65 5/65
(THICKNESS OF THERMOSETTING RESIN LAYER/BUMP HEIGHT) DICING
PROPERTY .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle.
TABLE-US-00002 TABLE 2 COMPARATIVE COMPARATIVE COMPARATIVE
COMPARATIVE EXAMPLE 1 EXAMPLE 2 EXAMPLE 3 EXAMPLE 4 PASTING
TEMPERATURE (.degree. C.) 65 100 75 75 SUPPORT BASE MATERIAL PET
PET PET EVA THICKNESS (.mu.m) 50 50 50 120 ADHESIVE LAYER TYPE OF
SOLUTION A A -- -- THICKNESS 30 30 -- -- ULTRAVIOLET RAY 400 400 --
-- IRRADIATION INTENSITY (mJ/cm.sup.2) SHEAR MODULUS (Pa) AT 2.9
.times. 10.sup.5 4.5 .times. 10.sup.4 -- -- PASTING TEMPERATURE
THERMOSETTING TYPE OF SOLUTION b C a a RESIN LAYER THICKNESS
(.mu.m) 40 40 40 40 MELT VISCOSITY (Pa S) AT 1.6 .times. 10.sup.5
8.9 .times. 10.sup.1 1.5 .times. 10.sup.3 1.5 .times. 10.sup.3
PASTING TEMPERATURE INITIAL PEEL STRENGTH (N/20 mm) OF ADHESIVE
0.04 0.04 -- -- LAYER FROM THERMOSETTING RESIN LAYER IRRADIATION
WITH ULTRAVIOLET RAY BEFORE NO NO -- -- PEELING PEEL STRENGTH (N/20
mm) OF ADHESIVE LAYER -- -- -- -- FROM THERMOSETTING RESIN LAYER
BEFORE PEELING AND AFTER IRRADIATION WITH ULTRAVIOLET RAY PEELING
PROPERTY .largecircle. .largecircle. .largecircle. X WHETHER TIP OF
BUMP IS EXPOSED OR NOT X X X .largecircle. THICKNESS RATIO 40/65
40/65 40/65 40/65 (THICKNESS OF THERMOSETTING RESIN LAYER/BUMP
HEIGHT) DICING PROPERTY -- .largecircle. -- --
(Results)
[0159] In the films for forming a protective layer of Examples 1 to
9, the bump could protrude from the thermosetting resin layer. On
the other hand, the tip of the bump was not exposed in Comparative
Example 1 because the melt viscosity of the thermosetting resin
layer at the pasting temperature was as high as 1.6.times.10.sup.5
PaS. In Comparative Example 2, the resin that constitutes the
thermosetting resin layer was washed away upon pasting and the
protective layer could not be formed because the melt viscosity of
the thermosetting resin layer at the pasting temperature was as low
as 8.9.times.10.sup.1 PaS. In Comparative Example 3, the bump
contacted a hard PET film of the support base and the tip of the
bump was not exposed because no adhesive layer existed. In
Comparative Example 4, although the tip of the bump could be
exposed by embedding the bump into a soft EVA film of the support
base because no adhesive layer existed, the thermosetting resin
layer could not be peeled from the support base.
* * * * *