JPS62119263A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:An epoxy resin composition, containing polypropylene powder and useful as a resin having high water resistance and low stress at the same time for sealing semiconductors. CONSTITUTION:An epoxy resin composition obtained by blending 1-20pts.wt. polypropylene powder with 100pts.wt. epoxy resin. The polypropylene powder to be used has >=140 deg.C melting point. 250-500pts.wt. inorganic filler and 20-100 pts.wt. curing agent having phenolic hydroxyl groups are further blended to give the aimed composition. The polypropylene powder has preferably the melting point about equal to or higher than the molding temperature or after-curing temperature. Novolak type resin is preferably used as the epoxy resin and silica is preferably used as the filler. Phenolic novolak is preferred for the curing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary of the Invention] The present invention provides an epoxy resin composition for semiconductor encapsulation containing polypropylene, which has high water resistance and low stress characteristics.

[Industrial application field]

The present invention relates to an epoxy resin composition for semiconductor encapsulation, and more particularly to an epoxy resin composition for semiconductor encapsulation that contains polypropylene and has high water resistance and low stress.

[Prior art and problems]

Conventionally, materials such as epoxy, silicone, and phenolic materials have been used as sealing resins for electrical parts and devices such as semiconductors. Among them, epoxy resin compositions using phenol novolac resin as a curing agent have good electrical properties and
It has an excellent balance of water resistance and adhesion to metal inserts, making it the mainstream sealing resin.

In such semiconductor parts, semiconductor patterns have become thinner and semiconductor chips have become larger, and as a result, there has been a demand for resins for use with semiconductors that have lower stress and excellent water resistance.

Conventionally, methods for reducing stress in a sealing resin composition include reducing the crosslinking density and adding a flexibilizing agent. However, these methods have the problem of deteriorating water resistance. It is also possible to reduce the coefficient of linear expansion by increasing the amount of filler added, but this method lowers the fluidity and causes defects such as wire open (breakage 'a) of the bonding wire.

On the other hand, if the crosslinking density is increased in order to improve the water resistance of the sealing resin composition, the resin will become harder and stress will increase. It has been difficult with conventional techniques to simultaneously achieve such low stress and high water resistance.

[Means for solving problems]

According to the present invention, the above problems are solved by an epoxy resin composition for semiconductor encapsulation characterized by containing polypropylene powder.

In the present invention, it is desirable to contain 1 to 20 parts by weight of the polypropylene powder per 100 parts by weight of the epoxy resin in order to obtain appropriate hardness during molding or after curing.

In addition, the melting point of the polypropylene powder must be 140"C or higher when low-pressure transfer molding of ICs, LSIs, etc. or the temperature during after-curing must be at least 15"C.
It is preferable to have a melting point of 0° C. or higher, and it is particularly preferable that the melting point is about the same as or higher than the molding temperature or after-cure temperature.

Furthermore, in the present invention, 250 to 500 parts by weight of the inorganic filler is contained per 100 parts by weight of the epoxy resin, because if it is less than 250 parts by weight, the coefficient of linear expansion will increase, and if it exceeds 500 parts by weight, the fluidity will deteriorate. preferable.

In addition, in the present invention, the curing agent 20 having a phenolic hydroxyl group is
It is preferable to include 100 parts by weight from the viewpoint of a good curing reaction with the epoxy resin.

That is, the present invention uses the property of polypropylene in a fluid or molten state to relax the stress generated when the epoxy resin cures and shrinks during molding.

Further, polypropylene has the advantage of not containing hydrophilic groups such as hydroxyl groups in its molecules and has excellent water resistance.

As the epoxy resin in the present invention, a novolac type epoxy resin is preferable from the viewpoint of electrical properties, water resistance, and moldability. Further, as the inorganic filler, it is desirable to use a material with good heat dissipation properties such as silica or alumina. As the curing agent having a phenolic hydroxyl group, phenol novolak is preferred from the viewpoint of water resistance. Furthermore, if the inorganic filler and the resin are cross-linked using a silane coupling agent such as 3-glycidoxypropyltrimethoxysilane, water resistance, strength, etc. can be improved. Also, hardening accelerators represented by imidazoles such as 2-methylimidazole, mold release agents such as carnauba wax, il! such as brominated epoxy, antimony oxide, etc. Known materials such as fuel and pigments such as carbon black can be used.

〔Example〕

100 parts by weight of cresol novolac type epoxy resin with an epoxy equivalent of 220 (hereinafter referred to as parts), a hydroxyl equivalent of 1
05 phenol novolac 60 parts, median diameter 12
380 parts of μm silica powder, 2 parts of 3-glycidoxypropyltrimethoxysilane, 2 parts of 2-phenylimidazole
1.5 parts of ester wax and 10 parts of polypropylene powder with a melting point of 175°C were heated at 60 to 80°C using a heated roll.
The resulting composition was made into a powder of 10 mesh passes.

Next, using 50 g of this powder, the pressure was 3 ton/c+.
Tablet under the condition of “w”, transfer pressure 50k
Transfer molding was performed at g/cL of 112, molding temperature of 175° C., and molding time of 2 minutes, and the stress of the molded product was measured by the piezo element method. Further, the molded product was subjected to post-curing treatment at 175° C. for 5 hours, and the stress, flexural modulus, and boiling water absorption were measured. The results are shown in Table 1.

[Comparative example]

A molded article was obtained using the same composition and method as in the example except that polypropylene was omitted, and then the characteristics were measured in the same manner as in the above example. The results are shown in Table 1.

Table 1 According to Table 1, the Examples are lower than the Comparative Examples.
It can be seen that it has low stress and high water resistance.

〔Effect of the invention〕

According to the present invention, by using polypropylene that does not have parent wood groups and has a melting point near the molding temperature and after-cure temperature, it is possible to alleviate the stress associated with curing shrinkage as shown in Table 1, so it is low stress and water resistant. Excellent in sex.

Claims (1)

[Scope of Claims] 1. An epoxy resin composition for semiconductor encapsulation, characterized by containing polypropylene powder. 2. Add the polypropylene powder to the epoxy resin 10
The composition according to claim 1, which contains 1 to 20 parts by weight relative to 0 parts by weight. 3. The composition according to claim 1, wherein the polypropylene powder has a melting point of 140°C or higher. 4. Claim 1, which contains 250 to 500 parts by weight of an inorganic filler and 20 to 100 parts by weight of a curing agent having a phenolic hydroxyl group based on 100 parts by weight of the epoxy resin.
Compositions as described in Section.