U.S. patent application number 13/770289 was filed with the patent office on 2013-08-29 for underfill material and method for manufacturing semiconductor device by using the same.
This patent application is currently assigned to DEXERIALS CORPORATION. The applicant listed for this patent is DEXERIALS CORPORATION. Invention is credited to Taichi KOYAMA.
Application Number | 20130224913 13/770289 |
Document ID | / |
Family ID | 49003304 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130224913 |
Kind Code |
A1 |
KOYAMA; Taichi |
August 29, 2013 |
UNDERFILL MATERIAL AND METHOD FOR MANUFACTURING SEMICONDUCTOR
DEVICE BY USING THE SAME
Abstract
Provided is an underfill material which enables a semiconductor
chip to be mounted at a low pressure, and a method for
manufacturing a semiconductor device by using the underfill
material. The method comprises: a semiconductor chip mounting step
configured to mount a semiconductor chip having a solder bump on a
substrate via an underfill film including a film forming resin
having a weight average molecular weight of not more than 30000
g/mol and a molecular weight distribution of not more than 2.0, an
epoxy resin, and an epoxy curing agent; and a reflow step
configured to solder-bond the semiconductor chip and the substrate
by a reflow furnace. The film forming resin of the underfill
material has a weight average molecular weight of not more than
30000 g/mol and a molecular weight distribution of not more than
2.0, and accordingly, the viscosity at the time of heat melting can
be reduced, and a semiconductor chip can be mounted at a low
pressure.
Inventors: |
KOYAMA; Taichi; (Tochigi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DEXERIALS CORPORATION; |
|
|
US |
|
|
Assignee: |
DEXERIALS CORPORATION
Tokyo
JP
|
Family ID: |
49003304 |
Appl. No.: |
13/770289 |
Filed: |
February 19, 2013 |
Current U.S.
Class: |
438/124 ;
525/118 |
Current CPC
Class: |
H01L 21/56 20130101;
H01L 23/293 20130101; C08L 67/02 20130101; C08L 75/04 20130101;
C08L 75/08 20130101; H01L 2924/0002 20130101; C08G 59/42 20130101;
C08G 2261/126 20130101; H01L 2924/0002 20130101; C08L 63/00
20130101; H01L 24/81 20130101; C08L 33/08 20130101; C08L 63/00
20130101; H01L 21/563 20130101; C08L 29/14 20130101; H01L 2924/00
20130101; C08L 29/10 20130101; C08L 53/00 20130101; C08L 33/10
20130101; C08L 53/00 20130101; H01L 2224/81815 20130101; C08L 29/02
20130101; C08L 75/06 20130101; H01L 2224/81091 20130101 |
Class at
Publication: |
438/124 ;
525/118 |
International
Class: |
C08L 53/00 20060101
C08L053/00; H01L 21/56 20060101 H01L021/56; C08L 63/00 20060101
C08L063/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 24, 2012 |
JP |
2012-038482 |
Claims
1. An underfill material, comprising: a film forming resin having a
weight average molecular weight of not more than 30000 g/mol, and a
molecular weight distribution of not more than 2.0; an epoxy resin;
and an epoxy curing agent.
2. The underfill material according to claim 1, wherein the
above-mentioned epoxy curing agent is an acid anhydride.
3. The underfill material according to claim 2, wherein the
above-mentioned film forming resin is a tri-block copolymer of
p-hydroxystyrene and ethyl vinyl ether.
4. The underfill material according to claim 3, wherein a
composition ratio of the above-mentioned p-hydroxystyrene to the
above-mentioned ethyl vinyl ether (p-hydroxystyrene/ethyl vinyl
ether) is not less than 20/80 and not more than 70/30, and not less
than 15 parts by mass and not more than 90 parts by mass of the
above-mentioned epoxy curing agent with respect to 100 parts by
mass of epoxy resin are blended.
5. The underfill material according to claim 3, wherein a
composition ratio of the above-mentioned p-hydroxystyrene to the
above-mentioned ethyl vinyl ether (p-hydroxystyrene/ethyl vinyl
ether) is not less than 30/70 and not more than 50/50, and not less
than 40 parts by mass and not more than 70 parts by mass of the
above-mentioned epoxy curing agent with respect to 100 parts by
mass of epoxy resin are blended.
6. A method of manufacturing a semiconductor device comprises: a
semiconductor chip mounting step configured to mount a
semiconductor chip having a solder bump on a substrate via an
underfill film including a film forming resin having a weight
average molecular weight of not more than 30000 g/mol and a
molecular weight distribution of not more than 2.0, an epoxy resin,
and an epoxy curing agent; and a reflow step configured to
solder-bond the above-mentioned semiconductor chip and the
above-mentioned substrate by a reflow furnace.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an underfill material used
for mounting semiconductors, and a method for manufacturing a
semiconductor device by using the underfill material.
[0003] 2. Description of the Related Art
[0004] In recent years, in a method of mounting a semiconductor
chip to a substrate, a use of an "pre-provided underfill film" has
been considered in order to shorten a step, the use of the
pre-provided underfill film being such that, before metal bonding
or pressure welding bonding of a semiconductor IC (Integrated
Circuit) electrode and a substrate electrode, an underfill film is
stuck on a substrate.
[0005] The mounting method using this pre-provided underfill film
is performed, for example, as follows (For example, refer to
Japanese Patent Application Laid-Open No. 2009-239138 and Japanese
Patent Application Laid-Open No. 2011-014717.).
[0006] Step A: An underfill film is stuck on a wafer, and then
dicing is carried out to obtain a semiconductor chip.
[0007] Step B: The semiconductor chip is aligned on a
substrate.
[0008] Step C: The semiconductor chip and the substrate are
pressure-bonded at a high temperature and a high pressure to secure
electrical connection by solder bump metal bonding and to bond the
semiconductor chip and the substrate together by curing of the
underfill.
[0009] However, according to the above-mentioned mounting method,
in the step C, since a semiconductor chip and a substrate need to
be pressure-bonded at a relatively high pressure, there is a risk
of damage to the semiconductor chip.
[0010] The present invention is proposed to solve the
above-mentioned conventional problem, and provides an underfill
material which enables a semiconductor chip to be mounted at a low
pressure, and a method for manufacturing a semiconductor device by
using the underfill material.
SUMMARY OF THE INVENTION
[0011] In order to solve the above-mentioned problem, an underfill
material according to the present invention comprises: a film
forming resin having a weight average molecular weight of not more
than 30000 g/mol and a molecular weight distribution of not more
than 2.0; an epoxy resin; and an epoxy curing agent.
[0012] Furthermore, a method for manufacturing a semiconductor
device according to the present invention comprises: a
semiconductor chip mounting step configured to mount a
semiconductor chip having a solder bump on a substrate via an
underfill film including a film forming resin having a weight
average molecular weight of not more than 30000 g/mol and a
molecular weight distribution of not more than 2.0, an epoxy resin,
and an epoxy curing agent; and a reflow step configured to
solder-bond the semiconductor chip and the substrate by a reflow
furnace.
[0013] In the present invention, since the film forming resin
included in the underfill material has a weight average molecular
weight of not more than 30000 g/mol and a molecular weight
distribution of not more than 2.0, the viscosity at the time of
heat melting can be reduced, and a semiconductor chip can be
mounted at a low pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a flow chart illustrating a method for
manufacturing a semiconductor device according to the present
embodiment.
[0015] FIG. 2 is a perspective view schematically illustrating a
step of sticking an underfill film on a wafer.
[0016] FIG. 3 is a perspective view schematically illustrating a
step of dicing the wafer.
[0017] FIG. 4 is a perspective view schematically illustrating a
step of picking up a semiconductor chip.
[0018] FIG. 5 is a perspective view schematically illustrating a
step of mounting the semiconductor chip on a substrate.
[0019] FIG. 6 is a cross-sectional diagram illustrating a state of
good solder connection and good solder wetting.
[0020] FIG. 7 is a cross-sectional diagram illustrating a state of
good solder connection and insufficient solder wetting.
[0021] FIG. 8 is a cross-sectional diagram illustrating a state of
insufficient solder connection and insufficient solder wetting.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Hereinafter, an embodiment according to the present
invention will be described in detail in the following order.
[0023] 1. Underfill Material
[0024] 2. Method for Manufacturing Semiconductor Device
[0025] 3. Examples
1. Underfill Material
[0026] An underfill material according to the present embodiment
comprises a film forming resin, an epoxy resin, and an epoxy curing
agent.
[0027] The film forming resin has a weight average molecular weight
Mw of preferably not less than 5000 g/mol and not more than 30000
g/mol, more preferably not less than 10000 g/mol and not more than
25000 g/mol. When the weight average molecular weight Mw exceeds
30000 g/mol, the minimum melt viscosity becomes high, whereby it is
difficult to mount a semiconductor chip at a low pressure. On the
other hand, when the weight average molecular weight Mw is too low,
the film forming property is worsened.
[0028] Furthermore, the film forming resin has a molecular weight
distribution (Mw/Mn) of not more than 2.0, the molecular weight
distribution (Mw/Mn) being represented by a ratio of a weight
average molecular weight Mw to a number average molecular weight
Mn. When the molecular weight distribution exceeds 2.0, it becomes
difficult to obtain a low minimum melt viscosity. A resin having
such a narrow molecular weight distribution can be obtained by, for
example, living polymerization. Furthermore, a resin having a
narrow molecular weight distribution can be obtained also by, for
example, a common technique, such as adjusting a kind or an amount
of a catalyst.
[0029] The film forming resin is not particularly limited as long
as the above-mentioned physical properties are satisfied, and, for
example, various resins, such as polyvinyl phenol resin, phenoxy
resin, polyester urethane resin, polyester resin, polyurethane
resin, acrylate resin, polyimide resin, and butyral resin, may be
used. These film forming resins may be used alone, or two or more
kinds of these may be used in combination.
[0030] Among these, from viewpoints of film formation state,
connection reliability, and the like, polyvinyl phenol resin is
preferably used. Examples of the polyvinyl phenol resin include a
tri-block copolymer obtained by living cationic polymerization of
p-hydroxystyrene (PHS) and ethyl vinyl ether (EVE).
[0031] In the case where a copolymer of p-hydroxystyrene (PHS) and
ethyl vinyl ether (EVE) is used, a composition ratio thereof
(PHS/EVA) is preferably not less than 20/80 and not more than
70/30, more preferably not less than 30/70 and not more than 50/50.
Since p-hydroxystyrene functions also as an epoxy curing agent, an
amount of an epoxy curing agent blended can be adjusted.
[0032] When an amount of the film forming resin used is too small,
a film tends not to be formed, on the other hand, when an amount
thereof is too much, a resin removal property for obtaining
electric connection tends to be low, and therefore, an amount of
the film forming resin used is preferably 30 to 80% by mass of a
resin solid content (a total of a film forming resin and an epoxy
resin), more preferably 40 to 70% by mass.
[0033] Examples of the epoxy resin include glycidyl ether type
epoxy resin, such as tetrakis(glycidyloxyphenyl)ethane and
tris(glycidyloxyphenyl)methane, glycidyl amine type epoxy resin,
such as tetraglycidyl diaminodiphenylmethane, bisphenol A type
epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy
resin, spirocyclic epoxy resin, naphthalene type epoxy resin,
biphenyl type epoxy resin, terpene type epoxy resin,
tetrabromobisphenol A type epoxy resin, cresol novolak type epoxy
resin, phenol novolak type epoxy resin, .alpha.-naphthol novolak
type epoxy resin, and brominated phenol novolak type epoxy resin.
These epoxy resins may be used alone, or two or more kinds of these
may be used in combination. Among these, from viewpoints of high
adhesiveness and heat resistance, glycidyl ether type epoxy resin
is preferably used.
[0034] The epoxy curing agent is not particularly limited, but, in
the case where solder is used for an electrode, an acid anhydride
having a flux function to remove an oxide film on a surface of the
solder is preferably used as an epoxy curing agent. Examples of the
acid anhydride curing agent include aliphatic acid anhydride, such
as tetrapropenyl succinic anhydride and dodecenyl succinic
anhydride; alicyclic acid anhydride, such as hexahydrophthalic
anhydride and methyltetrahydrophthalic anhydride; and aromatic acid
anhydride, such as phthalic anhydride, trimellitic anhydride, and
pyromellitic anhydride. These epoxy curing agents may be used
alone, or two or more kinds of these may be used in combination.
Among these epoxy curing agents, from a viewpoint of solder
connection property, aliphatic acid anhydride is preferably
used.
[0035] An effective curing amount of the epoxy curing agent is
blended. When an amount of the epoxy curing agent used is too
small, solder wetting tends to be insufficient, on the other hand,
when an amount thereof is too large, the preservation stability
tends to be decreased. In the case where aliphatic acid anhydride
is used as an epoxy curing agent, not less than 15 parts by mass
and not more than 90 parts by mass of the aliphatic acid anhydride
with respect to 100 parts by mass of an epoxy resin is preferable,
and not less than 40 parts by mass and not more than 70 parts by
mass thereof is more preferable.
[0036] Furthermore, a curing accelerator may be contained as
needed. Specific examples of the curing accelerator include
tertiary amines, such as 1,8-diazabicyclo(5,4,0)undecene-7 salt
(DBU salt) and 2-(dimethylaminomethyl)phenol; imidazoles, such as
2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole;
phosphines, such as triphenylphosphine; and metallic compounds,
such as octyl tin. Furthermore, 0.1 to 5.0 parts by mass of the
curing accelerator with respect to 100 parts by weight of an epoxy
resin are blended as needed.
[0037] Furthermore, various compounding agents, such as a filler,
for example, silica, alumina, glass fiber, and talc; a mold
release; a pigment; a surface treatment agent; a viscosity
modifier; a plasticizer; a stabilizer; and a coupling agent, may be
blended as needed.
[0038] The underfill material having such composition comprises a
film forming resin having a weight average molecular weight of not
more than 30000 g/mol and a molecular weight distribution of not
more than 2.0, and accordingly, the viscosity at the time of heat
melting can be reduced, and a semiconductor chip can be mounted at
a low pressure. Also, acid anhydride is used as an epoxy curing
agent, whereby a flux function to remove an oxide film on a surface
of solder can be provided. Also, as the film forming resin, a
tri-block copolymer of p-hydroxystyrene and ethyl vinyl ether,
which functions also as an epoxy curing agent, is used, whereby an
amount of an epoxy curing agent blended can be adjusted.
[0039] Next, a method for manufacturing the above-mentioned
underfill material will be explained. Here, there is explained a
method for manufacturing an underfill film in which an underfill
material is formed in a film shape. The method for manufacturing
the underfill film comprises: an application step of applying a
composite onto a release base material, the composite including a
film forming resin having a weight average molecular weight of not
more than 30000 g/mol and a molecular weight distribution of not
more than 2.0, an epoxy resin, and an epoxy curing agent; and a
drying step of drying the composite on the release base
material.
[0040] In the application step, the composite, which comprises the
film forming resin, the epoxy resin, and the epoxy curing agent and
is adjusted so as to have the above-mentioned composition, is
applied on a release base material by using a bar coater, an
application apparatus, or the like. The release base material has a
lamination structure, for example, configured such that a release
agent, such as silicone, is applied to PET (Poly Ethylene
Terephthalate), OPP (Oriented Polypropylene), PMP
(Poly-4-methlpentene-1), PTFE (Polytetrafluoroethylene), or the
like, whereby the composite is prevented from drying and also a
shape of the composite is maintained. The composite is dissolved in
an organic solvent and obtained. As the organic solvent, toluene,
ethyl acetate, a mixed solvent obtained by mixing toluene with
ethyl acetate, or other various organic solvents may be used.
[0041] In the subsequent drying step, the composite on the release
base material is dried by a heat oven, a heat-drying apparatus, or
the like. Thus, there can be obtained the underfill film comprising
a film forming resin having a weight average molecular weight of
not more than 30000 g/mol and a molecular weight distribution of
not more than 2.0, an epoxy resin, and an epoxy curing agent.
2. Method for Manufacturing Semiconductor Device
[0042] Next, a method for manufacturing a semiconductor device by
using the above-mentioned underfill film will be explained.
[0043] FIG. 1 is a flow chart illustrating a method for
manufacturing a semiconductor device according to the present
embodiment. As shown in FIG. 1, a method for manufacturing a
semiconductor device according to the present embodiment comprises
an underfill film sticking step S1, a dicing step S2, a
semiconductor chip mounting step S3, and a reflow step S4.
[0044] FIG. 2 is a perspective view schematically illustrating a
step of sticking an underfill film on a wafer. As shown in FIG. 2,
in the underfill film sticking step S1, a wafer 11 is fixed by a
jig 13 having a frame in a ring or rectangular shape with a larger
diameter than a diameter of the wafer 11, and an underfill film 12
is stuck on the wafer 11. The underfill film 12 functions as a
dicing tape to protect and fix the wafer 11 at the time of dicing
of the wafer 11 and to hold the wafer 11 at the time of picking-up.
Note that many ICs (Integrated Circuits) are made in the wafer 11,
and, on an adhesion face of the wafer 11, a solder bump is prepared
every semiconductor chip divided by scribe lines.
[0045] FIG. 3 is a perspective view schematically illustrating a
step of dicing a wafer. As shown in FIG. 3, in the dicing step S2,
the wafer 11 is cut by pressing a blade 14 along scribe lines, and
thereby divided into independent semiconductor chips.
[0046] FIG. 4 is a perspective view schematically illustrating a
step of picking up a semiconductor chip. As shown in FIG. 4, each
semiconductor chip 15 with the underfill film 12 is held by the
underfill film 12 and picked up.
[0047] FIG. 5 is a perspective view schematically illustrating a
step of mounting a semiconductor chip on a substrate. A substrate
16 is, for example, a rigid substrate or a flexible substrate, and
an electrode to be electrically connected with a solder bump of the
semiconductor chip 15 is formed in a mounting portion on which the
semiconductor chip 15 is to be mounted.
[0048] As shown in FIG. 5, in the semiconductor chip mounting step
S3, the semiconductor chip 15 with the underfill film 12 and the
substrate 16 are disposed via the underfill film 12. Furthermore,
the semiconductor chip 15 with the underfill film 12 is positioned
and disposed so as to make a solder bump and a substrate electrode
face each other.
[0049] Then, the underfill film 12 is heat-pressed to be
temporarily fixed under predetermined conditions of temperature,
pressure, and time, having a degree in which a flowability is
produced by a thermal bonder while full curing is not caused. The
temperature condition at the time of the temporal fixing is
preferably not less than 60 degrees C. and not more than 150
degrees C., more preferably not less than 80 degrees C. and not
more than 120 degrees C. The pressure condition is preferably not
more than 10 N, more preferably not more than 8 N. The time
condition is preferably not less than 1 second and not more than
120 seconds, more preferably not less than 5 seconds and not more
than 60 seconds. Thus, it is made possible that, without melting,
the solder bump is maintained in contact with the electrode at a
side of the substrate 16, and the underfill film 12 is not
completely cured. Furthermore, since the temporal fixing is
performed at a low temperature, generation of a void is controlled,
and damage to the semiconductor chip 15 can be reduced.
[0050] In the subsequent reflow step S4, the solder bump is melted
by intense heat from a reflow furnace, whereby a metallic bond is
formed and the underfill film 12 is completely cured. A temperature
condition at the time of reflow, although depending on a kind of
the solder, is preferably not less than 200 degrees C. and not more
than 280 degrees C., more preferably not less than 240 degrees C.
and not more than 260 degrees C. Furthermore, a time condition is
preferably not less than 5 seconds and not more than 500 seconds,
more preferably not less than 10 seconds and not more than 100
seconds. Thus, a metallic bond of the solder bump and the substrate
electrode is formed and the underfill film 12 is completely cured,
whereby an electrode of the semiconductor chip 15 and the electrode
of the substrate 16 can be electrically and mechanically
connected.
[0051] As mentioned above, the method of manufacturing a
semiconductor device according to the present embodiment comprises:
the semiconductor chip mounting step S3 configured to mount the
semiconductor chip 15 having a solder bump on the substrate 16 via
the underfill film 12 including a film forming resin having a
weight average molecular weight of not more than 30000 g/mol and a
molecular weight distribution of not more than 2.0, an epoxy resin,
and an epoxy curing agent; and the reflow step S4 configured to
solder-bond the semiconductor chip 15 and the substrate 16 by a
reflow furnace, whereby the semiconductor chip 15 is mounted at a
relatively low pressure, and therefore damage to the semiconductor
chip 15 can be reduced.
[0052] Note that, in the above-mentioned embodiment, the underfill
film is made to function as a dicing tape, but is not limited to
this, and, by using a dicing tape independently, after dicing,
flip-chip mounting may be performed using the underfill film.
EXAMPLES
3. Examples
[0053] Hereinafter, Examples of the present invention will be
described. In the Examples, a tri-block copolymer obtained by
living cationic polymerization of p-hydroxystyrene (PHS) and ethyl
vinyl ether (EVE) was blended to produce a pre-provided underfill
film. Then, by using this underfill film, a semiconductor chip was
mounted on a substrate.
[0054] Here, there were evaluated the minimum melt viscosity of the
underfill film, the minimum mounting pressure of a mounting body,
solder connection state, presence and absence of a crack or a warp,
and presence and absence of a void. Note that the present invention
is not limited to these Examples.
[0055] [Evaluation Method]
[0056] (Minimum Melt Viscosity)
[0057] The minimum melt viscosity of a sample was measured by using
a rheometer (ARES manufactured by TA instruments) under conditions
of 5 degrees C./min and 1 Hz.
[0058] (Minimum Mounting Pressure)
[0059] As a minimum mounting pressure (N), there was set a minimum
set pressure capable of pressure-bonding the sample with changing a
set pressure of a flip chip bonder (FCB3 manufactured by Panasonic
Factory Solutions Co., Ltd.) and thereby making a solder bump being
in contact with an electrode at a side of a substrate.
[0060] (Solder Connection State)
[0061] The sample was cut, and a cross-section thereof was
polished, and, as shown in the cross-section diagrams illustrated
in FIG. 6 to FIG. 8, a state of a solder 20 between an electrode
151 of the semiconductor chip 15 and an electrode 161 of the
substrate 16 after curing the underfill film 12 was observed by SEM
(Scanning Electron Microscope). As shown in FIG. 6, a state of good
solder connection and good solder wetting was represented as
.circleincircle.. As shown in FIG. 7, a state of good solder
connection and insufficient solder wetting was represented as
.smallcircle.. As shown in FIG. 8, a state of insufficient solder
connection and insufficient solder wetting was represented as
x.
[0062] (Presence and Absence of Crack or Warp)
[0063] The sample was visually observed using a microscope, and
when either a crack or a warp of the sample was generated, such
state was represented as "Presence", while when neither a crack nor
a warp of the sample was generated, such state was represented as
"Absence". Note that, generally, generation of a warp increases a
possibility of having a bad influence on long-term reliability.
[0064] (Presence and Absence of Void)
[0065] The sample was observed using SAT (Scanning Acoustic
Tomograph, ultrasonic imaging device), and when a void was
generated, such state was represented as "Presence", while when a
void was not generated, such state was represented as "Absence".
Note that, generally, generation of a void increases a possibility
of having a bad influence on long-term reliability.
Example 1
[0066] An underfill film was produced as follows. Using a solvent
having a ratio of toluene to ethyl acetate of 50/50 wt %, 70 parts
by mass of a film forming resin, 40 parts by mass of a curing
agent, and 2 parts by mass of a curing catalyst with respect to 100
parts by mass of an epoxy resin were blended to produce an epoxy
resin composite.
[0067] As the film forming resin, there was used a tri-block
copolymer obtained by living cationic polymerization of
p-hydroxystyrene (PHS) and ethyl vinyl ether (EVE). Specifically,
MARUKA LYNCUR TB (PHS/EVE=50/50) manufactured by Maruzen
Petrochemical Co., Ltd. and having a composition ratio of PHS to
EVE of 50/50, a weight average molecular weight Mw of 20000 g/mol,
and a molecular weight distribution (Mw/Mn) of 1.8 was used.
Furthermore, JER 1031S manufactured by Mitsubishi Chemical
Corporation, RIKACID DDSA manufactured by New Japan Chemical Co.,
Ltd., and U-CAT5002 manufactured by San-Apro Ltd. were used as the
epoxy resin, the curing agent, and the curing catalyst,
respectively.
[0068] This epoxy resin composite was applied onto a siliconized
PET (Polyethylene Terephthalate) film, by using a bar coater, and
then, dried by blowing hot air having a temperature of 80 degrees
C. for 5 minutes, whereby an underfill film having a thickness of
30 .mu.m was produced.
[0069] The above-mentioned underfill film was stuck on a wafer, and
diced to obtain a semiconductor chip. Under a condition of a
temperature of 100 degrees C., while a pressure was applied as the
minimum mounting pressure until a solder bump of the semiconductor
chip made a contact with a bump at a side of the substrate,
pressure bonding was performed for 10 seconds, whereby the
semiconductor was mounted. Then, through a reflow furnace having a
maximum temperature of 260 degrees C., the semiconductor chip and
the substrate were solder-connected.
[0070] Table 1 shows evaluation results of the underfill film and
the mounting body of Example 1. It was found that the minimum melt
viscosity of the underfill film of Example 1 was less than 15.0
PaS, hence the underfill film of Example 1 had excellent
flowability. Also, it was found that the minimum mounting pressure
at the time of semiconductor mounting was less than 10.0 N, hence
mounting at a low pressure was possible. Also, the mounting body of
Example 1 had a state of good solder connection and good solder
wetting, and furthermore, neither a crack nor a warp was generated,
and no void was generated.
Example 2
[0071] An underfill film was produced and a mounting body was
produced in the same manner as in Example 1, except that 70 parts
by mass of a curing agent with respect to 100 parts by mass of an
epoxy resin were blended, and MARUKA LYNCUR TB (PHS/EVE=30/70)
manufactured by Maruzen Petrochemical Co., Ltd. and having a
composition ratio of PHS to EVE of 30/70, a weight average
molecular weight Mw of 20000 g/mol, and a molecular weight
distribution (Mw/Mn) of 1.8 was used as a film forming resin.
[0072] Table 1 shows evaluation results of the underfill film and
the mounting body of Example 2. It was found that the minimum melt
viscosity of the underfill film of Example 2 was less than 15.0
PaS, hence the underfill film of Example 2 had excellent
flowability. Also, it was found that the minimum mounting pressure
at the time of semiconductor mounting was less than 10.0 N, hence
mounting at a low pressure was possible. Also, the mounting body of
Example 2 had a state of good solder connection and good solder
wetting, and furthermore, neither a crack nor a warp was generated,
and no void was generated.
Example 3
[0073] An underfill film was produced and a mounting body was
produced in the same manner as in Example 1, except that 100 parts
by mass of a film forming resin with respect to 100 parts by mass
of an epoxy resin were blended, and MARUKA LYNCUR TB
(PHS/EVE=30/70) manufactured by Maruzen Petrochemical Co., Ltd. and
having a composition ratio of PHS to EVE of 30/70, a weight average
molecular weight Mw of 20000 g/mol, and a molecular weight
distribution (Mw/Mn) of 1.8 was used as the film forming resin.
[0074] Table 1 shows evaluation results of the underfill film and
the mounting body of Example 3. It was found that the minimum melt
viscosity of the underfill film of Example 3 was less than 15.0
PaS, hence the underfill film of Example 3 had excellent
flowability. Also, it was found that the minimum mounting pressure
at the time of semiconductor mounting was less than 10.0 N, hence
mounting at a low pressure was possible. Also, the mounting body of
Example 3 had a state of good solder connection and good solder
wetting, and furthermore, neither a crack nor a warp was generated,
and no void was generated.
Example 4
[0075] An underfill film was produced and a mounting body was
produced in the same manner as in Example 1, except that 15 parts
by mass of a curing agent with respect to 100 parts by mass of an
epoxy resin were blended, and MARUKA LYNCUR TB (PHS/EVE=70/30)
manufactured by Maruzen Petrochemical Co., Ltd. and having a
composition ratio of PHS to EVE of 70/30, a weight average
molecular weight Mw of 20000 g/mol, and a molecular weight
distribution (Mw/Mn) of 1.8 was used as the film forming resin.
[0076] Table 1 shows evaluation results of the underfill film and
the mounting body of Example 4. It was found that the minimum melt
viscosity of the underfill film of Example 4 was less than 15.0
PaS, hence the underfill film of Example 4 had excellent
flowability. Also, it was found that the minimum mounting pressure
at the time of semiconductor mounting was less than 10.0 N, hence
mounting at a low pressure was possible. Also, the mounting body of
Example 4 had a state of good solder connection and insufficient
solder wetting. Also, in the mounting body of Example 4, neither a
crack nor a warp was generated, and no void was generated.
Example 5
[0077] An underfill film was produced and a mounting body was
produced in the same manner as in Example 1, except that 90 parts
by mass of a curing agent with respect to 100 parts by mass of an
epoxy resin were blended, and MARUKA LYNCUR TB (PHS/EVE=20/80)
manufactured by Maruzen Petrochemical Co., Ltd. and having a
composition ratio of PHS to EVE of 20/80, a weight average
molecular weight Mw of 20000 g/mol, and a molecular weight
distribution (Mw/Mn) of 1.8 was used as the film forming resin.
[0078] Table 1 shows evaluation results of the underfill film and
the mounting body of Example 5. It was found that the minimum melt
viscosity of the underfill film of Example 5 was less than 15.0
PaS, hence the underfill film of Example 5 had excellent
flowability. Also, it was found that the minimum mounting pressure
at the time of semiconductor mounting was less than 10.0 N, hence
mounting at a low pressure was possible. Also, the mounting body of
Example 5 had a state of good solder connection and insufficient
solder wetting. Also, in the mounting body of Example 5, neither a
crack nor a warp was generated, and no void was generated.
Comparative Example 1
[0079] An underfill film was produced and a mounting body was
produced in the same manner as in Example 1, except that 30 parts
by mass of PHENOLITE TD2131 manufactured by DIC Corporation and 60
parts by mass of RIKACID DDSA manufactured by New Japan Chemical
Co., Ltd. with respect to 100 parts by mass of an epoxy resin were
blended as curing agents; and Phenotohto YP50 manufactured by
Nippon Steel Chemical Co., Ltd. and having a weight average
molecular weight Mw of 50000 g/mol, and a molecular weight
distribution (Mw/Mn) of 3.5 was used as a film forming resin.
[0080] Table 1 shows evaluation results of the underfill film and
the mounting body of Comparative Example 1. It was found that the
minimum melt viscosity of the underfill film of Comparative Example
1 was more than 15.0 PaS, hence the underfill film of Comparative
Example 1 had insufficient flowability. Also, it was found that the
minimum mounting pressure at the time of semiconductor mounting was
more than 10.0 N, hence a high pressure was required for the
semiconductor mounting. Also, the mounting body of Comparative
Example 1 had a state of insufficient solder connection and
insufficient solder wetting, and generation of a crack or a warp
and generation of a void were observed.
Comparative Example 2
[0081] An underfill film was produced and a mounting body was
produced in the same manner as in Example 1, except that 30 parts
by mass of PHENOLITE TD2131 manufactured by DIC Corporation and 60
parts by mass of RIKACID DDSA manufactured by New Japan Chemical
Co., Ltd. with respect to 100 parts by mass of an epoxy resin were
blended as curing agents; and Teisan Resin SG-P3 manufactured by
Nagase Chemtex Corporation and having a weight average molecular
weight Mw of 850000 g/mol, and a molecular weight distribution
(Mw/Mn) of 3.4 was used as a film forming resin.
[0082] Table 1 shows evaluation results of the underfill film and
the mounting body of Comparative Example 2. It was found that the
minimum melt viscosity of the underfill film of Comparative Example
2 was more than 15.0 PaS, hence the underfill film of Comparative
Example 2 had insufficient flowability. Also, it was found that the
minimum mounting pressure at the time of semiconductor mounting was
more than 10.0 N, hence a high pressure was required for the
semiconductor mounting. Also, the mounting body of Comparative
Example 2 had a state of insufficient solder connection and
insufficient solder wetting, and generation of a crack or a warp
and generation of a void were observed.
Comparative Example 3
[0083] An underfill film was produced and a mounting body was
produced in the same manner as in Example 1, except that MARUKA
LYNCUR TB (PHS/EVE=50/50) manufactured by Maruzen Petrochemical
Co., Ltd. and having a composition ratio of PHS to EVE of 50/50, a
weight average molecular weight Mw of 20000 g/mol, and a molecular
weight distribution (Mw/Mn) of 3.0 was used as a film forming
resin.
[0084] Table 1 shows evaluation results of the underfill film and
the mounting body of Comparative Example 3. It was found that the
minimum melt viscosity of the underfill film of Comparative Example
3 was more than 15.0 PaS, hence the underfill film of Comparative
Example 3 had insufficient flowability. Also, it was found that the
minimum mounting pressure at the time of semiconductor mounting was
more than 10.0 N, hence a high pressure was required for the
semiconductor mounting. Also, the mounting body of Comparative
Example 3 had a state of insufficient solder connection and
insufficient solder wetting, and generation of a crack or a warp
and generation of a void were observed.
TABLE-US-00001 TABLE 1 Compar- Compar- Compar- ative ative ative
Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Blending Component
ple 1 ple 2 ple 3 ple 4 ple 5 ple 1 ple 2 ple 3 Film MARUKA LYNCUR
TB (PHS/EVE = 50/50) 70 -- -- -- -- -- -- -- Forming Mw = 20000,
Mw/Mn = 1.8 (manufactured by Resin Maruzen Petrochemical Co., Ltd.)
MARUKA LYNCUR TB (PHS/EVE = 30/70) -- 70 100 -- -- -- -- -- Mw =
20000, Mw/Mn = 1.8 (manufactured by Maruzen Petrochemical Co.,
Ltd.) MARUKA LYNCUR TB (PHS/EVE = 70/30) -- -- -- 70 -- -- -- -- Mw
= 20000, Mw/Mn = 1.8 (manufactured by Maruzen Petrochemical Co.,
Ltd.) MARUKA LYNCUR TB (PHS/EVE = 20/80) -- -- -- -- 70 -- -- -- Mw
= 20000, Mw/Mn = 1.8 (manufactured by Maruzen Petrochemical Co.,
Ltd.) Phenotohto YP50 -- -- -- -- -- 70 -- -- Mw = 50000, Mw/Mn =
3.5 (manufactured by Nippon Steel Chemical Co., Ltd.) Teisan Resin
SG-P3 -- -- -- -- -- -- 70 -- Mw = 850,000, Mw/Mn = 3.4
(manufactured by Nagase Chemtex Corporation) MARUKA LYNCUR TB
(PHS/EVE = 50/50) -- -- -- -- -- -- -- 70 Mw = 20000, Mw/Mn = 3.0
(manufactured by Maruzen Petrochemical Co., Ltd.) Epoxy Resin JER
1031S 100 100 100 100 100 100 100 100 (manufactured by Mitsubishi
Chemical Corporation) Curing PHENOLITE TD2131 -- -- -- -- -- 30 30
-- Agent (manufactured by DIC Corporation) RIKACID DDSA 40 70 40 15
90 60 60 40 (manufactured by New Japan Chemical Co., Ltd.) Curing
U-CAT 5002 2 2 2 2 2 2 2 2 Catalyst (manufactured by San-Apro Ltd.)
Evaluation Minimum Melt Viscosity (Pa S) <15.0 <15.0 <15.0
<15.0 <15.0 >15.0 >15.0 >15.0 Minimum Mounting
Pressure (N) <10.0 <10.0 <10.0 <10.0 <10.0 >10.0
>10.0 >10.0 Solder Connection State .circleincircle.
.circleincircle. .circleincircle. .largecircle. .largecircle. X X X
Presence and Absence of Crack or Warp Ab- Ab- Ab- Ab- Ab- Pres-
Pres- Pres- sence sence sence sence sence ence ence ence Presence
and Absence of Void Ab- Ab- Ab- Ab- Ab- Pres- Pres- Pres- sence
sence sence sence sence ence ence ence
[0085] From the results shown in Table 1, it was found that an
underfill film comprising a film forming resin having a weight
average molecular weight of 30000 g/mol and a molecular weight
distribution of 2.0, an epoxy resin, and an epoxy curing agent had
excellent flowability and was possible to be mounted at a low
pressure.
[0086] Specifically, a film forming resin having a composition
ratio of p-hydroxystyrene to ethyl vinyl ether
(p-hydroxystyrene/ethyl vinyl ether) of not less than 20/80 and not
more than 70/30 was used, and not less than 15 parts by mass and
not more than 90 parts by mass of acid anhydride with respect to
100 parts by mass of epoxy resin were blended, whereby solder
connection was in a good state, and generation of a crack or a warp
and generation of a void were able to be prevented.
[0087] Furthermore, it was found that a film forming resin having a
composition ratio of p-hydroxystyrene to ethyl vinyl ether
(p-hydroxystyrene/ethyl vinyl ether) of not less than 30/70 and not
more than 50/50 was used, and not less than 40 parts by mass and
not more than 70 parts by mass of acid anhydride with respect to
100 parts by mass of epoxy resin were blended, whereby solder
wetting was in a good state.
* * * * *