JPH07150014A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition maintaining both heat resistance and moisture resistance, having low elastic modulus and excellent in high- temperature preservability, containing a flexibilizer, a preliminary reaction product from a modified silicone oil and phenol novolak resin. CONSTITUTION:This composition comprises (A) a flexibilizer prepared by reaction between (1) a modified silicone oil having epoxy group but having no nonepoxy-based organic group and (2) a phenol novolak resin at 120-10 deg.C) for 5-30 (pref. about 24) hr, (B) a novolak-type epoxy resin, (C) a curing agent, (D) a curing promoter, (E) a filler, (F) a releasant and (G) a surface-treating agent. It is preferable that the component (1) have epoxy groups at both ends of the molecule, in this case, epoxy equivalent 500-5000 and an epoxy group exist midway of the molecular chain and the equivalent ratio of the epoxy group in the component (1) to the OH group in the component (2) 0.001-0.3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an epoxy resin composition for semiconductor encapsulation. More specifically, it is an epoxy resin composition for semiconductor encapsulation which uses a pre-reacted product of a modified silicone oil having an epoxy group and a phenol novolac resin as a flexibilizer, and retains heat resistance and moisture resistance of the epoxy resin. And an epoxy resin composition for semiconductor encapsulation, which provides a cured product having a low elastic modulus and a low expansion coefficient.

[0002]

2. Description of the Related Art In recent years, the tendency of semiconductor devices to become larger and more highly integrated has increased, and when semiconductors are encapsulated with conventional epoxy resin compositions, the coefficient of linear expansion between the chip or lead frame and the encapsulating resin. The thermal stress due to the difference in linear expansion coefficient between the chip or the lead frame and the encapsulating resin causes the chip to crack, the bonding line to be cut, etc. There's a problem. This is because the conventional epoxy resin for semiconductor encapsulation has been developed from the viewpoint of heat resistance and water resistance, and the cured product thereof is extremely hard, has poor flexibility, and has a large stress applied to the element.

In order to reduce this stress, the elastic modulus, the expansion coefficient and the glass transition point may be lowered, but from the viewpoint of maintaining moisture resistance and heat resistance, the glass transition point is preferably high. There is a method of adding a flexibilizing agent as a method of lowering the stress, but in the method of lowering the elastic modulus with a conventional flexibilizing agent, the glass transition point of the cured product is largely lowered, and the electrical characteristics and humidity resistance at high temperature are increased. It is unsuitable as a resin composition for semiconductor encapsulation due to deterioration of properties.

In order to improve the electric characteristics at high temperature, there is a method of mixing a low elastic modulus silicone resin which is a heat-resistant flexing agent, but when the silicone resin is used, the adhesiveness to a metal becomes poor. However, since the moisture permeability is increased, there is a problem in that the moisture resistance is unreliable.

[0005]

As a flexibilizing agent having excellent moisture resistance and not lowering the glass transition point, polybutadiene having carboxyl groups at both terminals or polybutadiene having carboxyl groups at both terminals and acrylonitrile are added. A rubber-modified epoxy flexibilizer, which is obtained by reacting a polymer with an epoxy resin, has also been proposed, but when it is held at a high temperature, the unsaturated bond in the polybutadiene structure is oxidized and deteriorated, resulting in loss of flexibility. There's a problem.

Further, Japanese Patent Application Laid-Open No. 58-2322 discloses that
Although an epoxy resin composition for semiconductor encapsulation having excellent heat resistance, which contains a phenol novolac epoxy resin and a phenol novolac resin as a curing agent, is disclosed, but there is a problem that crack resistance is inferior.
No. 20 discloses an epoxy resin composition for semiconductor encapsulation containing a rubber component in an amount of 0.05 to 10% by weight and having excellent heat resistance (glass transition temperature and the like) and crack resistance. There is a problem of deterioration (strength reduction, weight reduction, etc.) when a storage test is performed.

[0007]

As a result of intensive studies to solve such problems, the present inventors have found that an epoxy resin composition having heat resistance and moisture resistance as a semiconductor encapsulating material and having a low elastic modulus. The present invention has been completed and the present invention has been completed. The present invention provides a flexible agent which is a pre-reactant of a modified silicone oil having an epoxy group and a phenol novolac resin,
The present invention relates to an epoxy resin composition for semiconductor encapsulation containing a novolac type epoxy resin, a curing agent, a curing accelerator, a filler, a release agent and a surface treatment agent.

[0008]

【Example】

Example 1. Examples of the novolac type epoxy resin used in the present invention include, but are not limited to, cresol novolac type epoxy resin, phenol novolac type epoxy resin, alkylbenzene-modified phenol novolac type epoxy resin, and brominated phenol novolac type epoxy resin. Not a thing. These may be used alone or in combination of two or more.

Examples of the curing agent used in the present invention include, but are not limited to, phenol novolac resin, cresol novolac resin, and alkyl-modified phenol novolac resin. These may be used alone or in combination of two or more.

The curing accelerator used in the present invention can be used without particular limitation as long as it is a usual catalyst. Specific examples thereof include phosphorus compounds such as triphenylphosphine and triphenylphosphite, and 2-methyl. Imidazoles such as imidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl and -4-methylimidazole,
2- (dimethylaminomethyl) phenol, 2,4,6
-Tertiary amines such as tris (dimethylaminomethyl) phenol, benzyldimethylamine, α-methylbenzylmethylamine, 1,8-diazabicyclo (5,4,4)
0) Undecene-7 and 1,8-diazabicyclo (5,4,0) undecene-7 organic acid salts and the like, and the addition amount thereof is 0.15 to 1% in the encapsulating resin composition.
0% (wt%, the same applies below) is sufficient.

Examples of the filler used in the present invention include crystalline silica powder and quartz glass powder. The addition amount of the filler is 50 to 80 in the resin composition for semiconductor encapsulation.
% Is desirable, and if it exceeds 80%, the fluidity of the composition tends to be low, making molding difficult, and if it is less than 50%, the linear expansion coefficient tends to increase. Examples of the release agent used in the present invention include natural wax, synthetic wax, higher fatty acid or its metal salt, and paraffins. The surface treatment agent used in the present invention is a surface treatment agent for a filler, and a known silane coupling agent is used.

In the present invention, a pre-reacted product of a modified silicone oil having an epoxy group and a phenol novolac resin is used as a flexibilizer. The preliminary reaction product of the modified silicone oil having an epoxy group and the phenol novolac resin is a mixture of the modified silicone oil having an epoxy group and the phenol novolac resin, and a phosphorus compound or an imidazole compound is added as a catalyst under a nitrogen atmosphere. It is obtained by reacting at 120 to 160 ° C. for 5 to 30 hours.

The modified silicone oil having an epoxy group may have an epoxy group at both ends of the molecule or in the middle of the molecular chain, and a resin composition using these has heat resistance and moisture resistance. It has a low elastic modulus and a low expansion coefficient. Of these, a resin composition using a modified silicone oil having epoxy groups at both ends of the molecule is particularly preferable because it has further excellent storage stability at high temperatures.

The modified silicone oil having epoxy groups at both ends of the molecule has an epoxy equivalent of 500 to 500.
A value of 0 is preferable. When the epoxy equivalent is less than 500, the silicone chain is shortened, and therefore, when the obtained composition is molded, the effect of making it flexible is likely to be insufficient. On the other hand, when it is more than 5,000, the molecular weight of the silicone oil becomes large, so that the compatibility with the phenol novolac resin becomes small and the reaction between the epoxy group of the silicone oil and the hydroxyl group of the phenol novolac resin tends to be insufficient.

The modified silicone oil having an epoxy group in the middle of the molecular chain has an epoxy equivalent of 500 to 400.
00 is preferable, and 1000 to 20000 is more preferable. Further, the number of epoxy groups per molecule is preferably about 2 to 10, particularly about 4 to 8. If the epoxy equivalent or the number of epoxy groups per molecule is out of the range, if the epoxy groups are few, the reaction does not proceed sufficiently during the reaction with the phenol novolac resin, or if the epoxy groups are many, It tends to gel.

As the phenol novolac resin,
It is preferable that the softening point is 60 to 110 ° C. Phosphines such as triphenylphosphine are used as the phosphorus compound used as the catalyst, and particularly 2
-Ethyl, -4-methylimidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole are preferred.

The compounding ratio of the modified silicone oil having an epoxy group and the phenol novolac resin is such that the equivalent ratio (epoxy group / phenolic hydroxyl group) between the epoxy group of the modified silicone oil having an epoxy group and the hydroxyl group of the phenol novolac resin is 0. The ratio is preferably 0.001 to 0.3, particularly 0.01 when using a modified silicone oil having epoxy groups at both ends of the molecule.
The ratio is preferably 0.3 to 0.3. When the equivalent ratio of the epoxy group of the modified silicone oil having an epoxy group to the hydroxyl group of the phenol novolac resin is less than 0.001, the ratio of the modified silicone oil component of the flexibilizing agent becomes small, and the semiconductor sealing Even if it is used as a material, the effect of making it flexible tends not to be sufficiently exhibited. On the other hand, when the equivalent ratio is larger than 0.3, gelation is likely to occur during the preliminary reaction between the modified silicone oil having an epoxy group and the phenol novolac resin, and it tends to be difficult to obtain a stable flexibilizing agent. It is in.

When the modified silicone oil has an epoxy group in the middle of the molecular chain, the addition amount of the catalyst is 0. 1 with respect to 100 parts of the modified silicone oil (parts by weight, hereinafter the same).
001 to 2.0 parts is preferable, and when a modified silicone oil having epoxy groups at both ends of the molecule is used, it is 0.01 to 100 parts with respect to the modified silicone oil.
4.0 parts is preferred.

In the pre-reacted product of the modified silicone oil having an epoxy group and the phenol novolac resin thus produced, 90% or more of the epoxy groups of the modified silicone oil react with the hydroxyl group of the phenol novolac resin in the pre-reaction. Those that are preferable. Especially when the reaction rate of the epoxy groups of the modified silicone oil having epoxy groups at both ends of the molecule with the hydroxyl groups of the phenol novolac resin is 90% or more, when the obtained resin composition is formed and kept at high temperature for a long time. It is possible to particularly reduce the decrease in strength.

The addition amount [S] of the flexibilizing agent is [S] / [R] with respect to the total amount of the addition amount [S] and the component amount [R] of the resin composition other than the flexing agent. ([S] + [R]) is 3 to 3
It is preferably in the range of 0%. If the ratio is less than 3%, the elastic modulus is less likely to decrease when the obtained composition is formed, and the flexibility-improving effect may not be sufficient.
If it exceeds, the glass transition point may be lowered, the mechanical strength may be lowered, and the electrical characteristics at high temperature may be greatly lowered.

In the composition of the present invention, the value of the ratio (epoxy group / phenolic hydroxyl group) of the epoxy group equivalent of the novolac type epoxy resin and the total equivalent of the phenolic hydroxyl groups in the curing agent and the flexibilizer. Is preferably in the range of 0.7 to 1.3 for the purposes of the present invention.

If desired, a colorant such as carbon, a flame retardant such as antimony trioxide, antimony pentoxide, or a phosphate may be added to the composition of the present invention. Less than,
The composition of the present invention will be specifically described based on Examples.

Example 2. Modified silicone oil having epoxy groups at both ends of a molecule having an epoxy equivalent of 2500 1
00 parts and phenol novolac resin (PSF 426
1, Gunei Chemical Co., Ltd.) 84.8 parts (epoxy group / phenolic hydroxyl group equivalent ratio: 0.05) and 1 part of triphenylphosphine while blowing nitrogen at 150 ° C.
For 24 hours, the modified silicone oil having epoxy groups at both ends of the molecule is pre-reacted with the phenol novolac resin, and the modified silicone oil having epoxy groups at both ends is pre-reacted with the flexible resin. Agent (A) was obtained.

Cresol novolac type epoxy resin (E
OCN 1020, manufactured by Nippon Kayaku Co., Ltd., brominated phenol novolac type epoxy resin (BREN-S, manufactured by Nippon Kayaku Co., Ltd.), phenol novolak resin (PSF4261) as a curing agent, curing accelerator, and flexibility. Agent (A), fused silica (RD-8, manufactured by Tatsumori Co., Ltd.) as a filler, and other materials (6 parts antimony trioxide, 1 part silane coupling agent, 1 part wax, 5 parts coloring agent) After mixing at the ratio shown in Table 1, kneading with a heating roll and cooling,
It was pulverized to prepare a molding epoxy resin composition. The obtained composition was molded under the condition of 175 ° C./3 minutes,
Post-curing was carried out at 6 ° C. for 6 hours to prepare a cured test piece.

The flexural elasticity (JI
SK6911), the glass transition point and the volume resistivity before and after the pressure cooker test for 500 hours at 121 ° C. and 2 atm. The results are shown in Table 1.

[0026]

[Table 1]

[Table 2]

[Table 3]

A high temperature storage test was carried out at 200 ° C. for 1000 hours, and the weight loss rate was calculated by the following equation.
It is 8%, which shows that the storage stability at high temperature is particularly excellent.

Example 3. ~ 8. As shown in Table 1, a curing test piece was prepared in the same manner as in Example 1 except that the ratio of the flexibilizer (A), the curing agent and the filler, and the type of the curing accelerator were changed, and the physical properties were evaluated. did. The results are shown in Table 1.

Example 9. Modified silicone oil having epoxy groups at both ends of a molecule having an epoxy equivalent of 500 10
0 parts and phenol novolac resin (PSF 4261)
212 parts (equivalent ratio of epoxy group / phenolic hydroxyl group:
0.1) and 1.5 times triphenylphosphine were reacted in the same manner as in Example 1 to obtain a flexibilizer (B). Curing test pieces were prepared in the same manner as in Example 1 except that the obtained flexibilizing agent (B) and the like were used as shown in Table 1, and the physical properties were evaluated. The results are shown in Table 1.

Example 10. 100 parts of a modified silicone oil having epoxy groups at both ends of a molecule having an epoxy equivalent of 5000, and a phenol novolac resin (PSF 42
61) 42.4 parts (equivalent ratio of epoxy group / phenolic hydroxyl group: 0.05) and triphenylphosphine 0.8
Was reacted in the same manner as in Example 1 to obtain a flexibilizer (C). Curing test pieces were prepared in the same manner as in Example 1 except that the obtained flexibilizing agent (C) and the like were used as shown in Table 1, and the physical properties were evaluated. The results are shown in Table 1.

Example 11. 100 parts of modified silicone oil having epoxy groups at both ends of a molecule having an epoxy equivalent of 2500, and a phenol novolac resin (PSF 42
61) 84.8 parts (equivalent ratio of epoxy group / phenolic hydroxyl group: 0.05) and 0.8 part of 2-ethyl-4-methylimidazole were reacted in the same manner as in Example 1, A flexing agent (D) was obtained. Curing test pieces were prepared in the same manner as in Example 1 except that the obtained flexibilizer (D) and the like were used as shown in Table 1, and the physical properties were evaluated. The results are shown in Table 1.

Example 12 Modified silicone oil having an epoxy group in the middle of the molecule with an epoxy equivalent of 8500 1
00 parts and phenol novolac resin (PSF 426
1) Gunei Chemical Co., Ltd.) 24.9 parts (epoxy group / phenolic hydroxyl group equivalent ratio: 0.05) and 0.1 part of triphenylphosphine were reacted in the same manner as in Example 1. , And a flexible agent (E) was obtained. Obtained flexibilizer (E)
Example 1 except that, etc. were used as shown in Table 1.
A cured test piece was prepared in the same manner as in, and the physical properties were evaluated. The results are shown in Table 1. Further, a high temperature storage test was conducted in the same manner as in Example 1 and the weight loss rate was calculated to be 1.6.
%, Which shows that the storage stability at high temperature is excellent.

Example 13. ~ 19. As shown in Table 1, a curing test piece was prepared in the same manner as in Example 12 except that the ratio of the flexibilizer (E), the curing agent and the filler, and the type of the curing accelerator were changed, and the physical properties were evaluated. did. The results are shown in Table 1.

Example 20. Epoxy equivalent 100 modified silicone oil having an epoxy group in the middle of 500 molecules
And phenol novolac resin (PSF4261) 2
12 parts (equivalent ratio of epoxy group / phenolic hydroxyl group:
0.1) and 0.8 part of triphenylphosphine were reacted in the same manner as in Example 1 to obtain a flexibilizer (F). Curing test pieces were prepared in the same manner as in Example 1 except that the obtained flexibilizer (F) and the like were used as shown in Table 1, and the physical properties were evaluated. The results are shown in Table 1.

Example 21. 100 parts of a modified silicone oil having an epoxy group in the middle of a molecule having an epoxy equivalent of 20,000 and a phenol novolac resin (PSF426
1) 10.6 parts (epoxy group / phenolic hydroxyl group equivalent ratio: 0.05) and triphenylphosphine 0.05
Was reacted in the same manner as in Example 1 to obtain a flexibilizer (G). Curing test pieces were prepared in the same manner as in Example 1 except that the obtained flexibilizer (G) and the like were used as shown in Table 1, and the physical properties were evaluated. The results are shown in Table 1.

Example 22. Modified silicone oil having an epoxy group in the middle of the molecule with an epoxy equivalent of 8500 1
00 parts and phenol novolac resin (PSF426
1) Using 249 parts (equivalent ratio of epoxy group / phenolic hydroxyl group: 0.05) and 0.05 part of 2-ethyl-4-methylimidazole to react in the same manner as in Example 1 to make it flexible. Agent (H) was obtained. Curing test pieces were prepared in the same manner as in Example 1 except that the obtained flexibilizer (H) and the like were used as shown in Table 1, and the physical properties were evaluated. The results are shown in Table 1.

Comparative Example 1. ~ 4. As the flexibilizer, DER736 manufactured by Dow Chemical Co., or Araldite GY298 manufactured by Ciba Geigy Co. was used to prepare an epoxy resin composition for encapsulation having the composition shown in Table 1, and a curing test was conducted in the same manner as in Example 1. Pieces were prepared and the physical properties were evaluated. The results are shown in Table 1.

Comparative Example 5. And 6. An epoxy resin composition for encapsulation having the composition shown in Table 1 was prepared without using a flexibilizer, and a cured test piece was prepared in the same manner as in Example 1, and the physical properties were evaluated. The results are shown in Table 1.

[0039]

As is apparent from the above results, the epoxy resin composition for semiconductor encapsulation using the pre-reacted product of the modified silicone oil having an epoxy group and the phenol novolac resin of the present invention as a flexibilizer, It retains heat resistance and moisture resistance, has a low elastic modulus, and especially those using modified silicone oil having epoxy groups at both ends of the molecule as modified silicone oil are particularly excellent in high temperature storage stability. It has an effect that it can be suitably used as a stopping epoxy resin composition.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ko Shimomura 4-1-1 Mizuhara, Itami-shi Kita Itami Works (72) Inventor Kazuro Okahashi 8-1-1 Tsukaguchihonmachi, Amagasaki Mitsubishi Electric Corporation Company Production Technology Laboratory

Claims (7)

[Claims] 1. A modified silicone oil having an epoxy group and not having a non-epoxy type organic group is reacted with a phenol novolac resin at a temperature of 120 to 160 ° C. for 5 to 30 hours, preferably about 24 hours. An epoxy resin composition for semiconductor encapsulation comprising a flexing agent, a novolac type epoxy resin, a curing agent, a curing accelerator, a filler, a release agent and a surface treatment agent. 2. The modified silicone oil according to claim 1, wherein the modified silicone oil has epoxy groups at both ends of the molecule.
The epoxy resin composition for semiconductor encapsulation according to the item. 3. The modified silicone oil according to claim 1, which has an epoxy group in the middle of the molecular chain.
The epoxy resin composition for semiconductor encapsulation according to the item. 4. The epoxy resin composition for semiconductor encapsulation according to claim 2, wherein the modified silicone oil having epoxy groups at both ends of the molecule has an epoxy equivalent of 500 to 5000. 5. The semiconductor according to claim 1, wherein an equivalent ratio (epoxy group / phenolic hydroxyl group) of the epoxy group of the modified silicone oil and the hydroxyl group of the phenol novolac resin is 0.001 to 0.3. Epoxy resin composition for encapsulation. 6. The equivalent ratio (epoxy group / phenolic hydroxyl group) of the epoxy group of the modified silicone oil having epoxy groups at both ends of the molecule and the hydroxyl group of the phenol novolac resin is 0.01 to 0.3. The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2. 7. A pre-reacted product of a modified silicone oil having epoxy groups at both ends of the molecule and a phenol novolac resin is 90% of the epoxy groups of the modified silicone oil.
The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, wherein at least 100% is obtained by reacting with a hydroxyl group of the phenol novolac resin.