JPH0214214A - Resin composition for sealing - Google Patents

Abstract

PURPOSE:To provide the title resin composition of high glass transition point and low stress, suitable for IC-sealed forms, comprising each specific polysiloxane-epoxy resin block-added form and bismaleimide resin and inorganic filler. CONSTITUTION:The objective composition comprising (A) a polysiloxane-epoxy resin block-added form produced by reaction, in the presence of a platinum-based catalyst, between a phenol-novolak epoxy resin partially containing alkenyl group and a hydrogenorganopolysiloxane of the formula (R1 and R2 are each alkyl, etc.; n is 50-300), (B) a bismaleimide resin produced by reaction between a bismaleimide (derivative) and an aromatic diamine and (C) an inorganic filler (pref. silica powder). This resin composition will give sealed forms excellent in soldering crack resistance reliability and temperature cycling resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sealing resin composition for obtaining an RC sealing body having a high glass transition point (Tg) and low stress.

[Conventional technology]

Currently, as a method for encapsulating semiconductor elements, resin encapsulation by transfer molding using an epoxy resin molding material is generally performed.

However, as semiconductor elements become more highly integrated, devices become larger and flatter, cured encapsulation materials become thinner, and surface mounting is used for mounting on substrates, more and more are required of encapsulation molding materials. In other words, the problem of stress caused by the difference in thermal expansion coefficient between the IC substrate carrier frame and the cured molded product due to temperature changes has become apparent, and the
C Slide of aluminum wiring, disconnection of bonding gold wire, I
Specific problems have arisen, such as separation of the C interface and the cured sealant, and cranking of the cured sealant.

Additionally, with the shift to surface mounting, solder heat resistance has come under scrutiny, resulting in the problem of cracks in the cured resin.

In order to deal with these problems, it is essential that the Tg of the cured resin is as high as possible, preferably at or above the solder bath temperature, and that the cured resin has low stress. Therefore, there is a natural limit to the ability of epoxy resins to simultaneously ensure both performances.

On the other hand, there is bismaleimide resin as a high ↑g resin that can be used as an alternative to epoxy resin, but the cured product of this resin has a high modulus of elasticity and can cause cracks in temperature cycle tests. It had the disadvantage of being inferior in gender. For this reason, conventional resins have high T as sealing resins.
Although a cured product can be obtained, it has been evaluated that it cannot be applied.

[Problem to be solved by the invention]

The present invention was achieved through intensive studies to improve the drawbacks of conventional bismaleimide resins, and its purpose is to: ■C without deteriorating the properties required for sealing cured resins. Another object of the present invention is to provide a resin composition for IC sealing that has low stress properties and provides a high Tg cured resin.

(Means for Solving the Problems) The present invention provides a polysiloxane-epoxy resin obtained by subjecting a phenol or novolac epoxy resin partially containing an alkenyl group to an addition reaction with a hydrogen organopolysiloxane in the presence of a platinum catalyst. This composition for semiconductor encapsulation contains as essential components a so-called bismaleimide-based resin obtained by reacting a resin block copolymer, bismaleimide and/or its derivative, and an aromatic diamine, and an inorganic filler.

The phenol-novolak epoxy resin partially containing alkenyl groups used in the present invention can be obtained by various methods, and the manufacturing method is not limited.

For example, a resin obtained by epoxidizing the phenolic hydroxyl group of a so-called co-condensed novolac synthesized from formalin of allylphenol and phenols, a phenol novolac-based epoxy resin, tributylamine, triphenylph A sphite, imidazole, etc. A resin obtained by adding a compound having a hydroxyl group such as allylphenol or allyl alcohol in the presence of a catalyst such as. Obtained by reacting phenolic novolac with allyl chloride and epichlorohydrin.

Epoxy resin or the like is used.

The polysiloxane-epoxy block copolymer used in the present invention is a reaction product obtained by reacting the above-mentioned epoxy resin partially containing allyl groups with hydrogen organopolysiloxane in the presence of a platinum-based catalyst. There is.

The hydrogen organopolysiloxane used is a polysiloxane represented by the following formula, and its degree of polymerization is from 50 to
The range is 300.

If the degree of polymerization is less than 50, the stress reduction effect of the cured resin will be reduced, and if it is more than 300, the hydrosilylation reaction with the epoxy resin will be difficult to complete.

Furthermore, the amount of polysiloxane added to the epoxy resin (Wtχ
) can be selected as appropriate, but is preferably 10 to 50%.

Although the reaction method can be selected as appropriate, it is preferable to use an aromatic hydrocarbon solvent, and as a catalyst, an isopropanol solution of platinum chlorate hydrate is preferably used. Naturally, after the reaction is completed, the solvent is removed by heating under reduced pressure to obtain a white block copolymer that is solid at room temperature. The white color of the copolymer is due to the formation of domains in the epoxy resin matrix due to the aggregation of polysiloxane units, and this higher-order so-called sea-island structure is the main cause of the stress-lowering properties. Become.

Further, the bismaleimide resin for constituting the composition of the present invention can be obtained by a Michael addition reaction between bismaleimide and/or a derivative thereof and an aromatic simian. It is an oligomer, and a typical commercially available product is Kelimide from Rhone-Bouland. Naturally, the ratio of both components, the polymerization degree distribution of the obtained oligomer, etc. affect the Tg of the final cured product, so it is preferable to synthesize and use it as appropriate. Although cured products using a radical initiator or simian using only the resin have a high Tg, they are inferior in adhesion and mechanical toughness, so it is common to obtain a molding material composition in combination with an epoxy resin, and this method is a widely used method.

The blending ratio of the polysiloxane-epoxy resin bronch adduct and the bismaleimide resin is appropriately determined in view of the properties of the cured product. The cured resin of the mixture of the two is yellowish white, and it can be seen that even after curing, the tomeia caused by the aggregation of the origaripolysiloxane units remains stably.

Inorganic fillers used in the present invention include silica powder, alumina, antimony dioxide, aluminum hydroxide hydrate,
Examples include titanium oxide, which may be used alone or in combination of two or more.

Among these, silica powder is preferably used as the semiconductor encapsulating material composition. The amount of inorganic filler blended must be 50 to 80% by weight based on the total resin composition and filler, and if it is less than 50% by weight, the performance of the cured composition will be insufficient. If it exceeds % by weight, the moldability is poor and it is not suitable for practical use.

In addition to the above-mentioned essential components, a curing accelerator, a lubricant, a flame retardant, a mold release agent, a silane coupling agent, etc. can be added as appropriate when forming the molding material.

A general method for preparing the resin composition for semiconductor encapsulation of the present invention as a molding material is to knead the composition obtained by adding various additives to the above-mentioned essential component mixture using a kneader 1 heated roll. After processing, it can be cooled and pulverized to form a molding material. The obtained molding material can be applied to semiconductor encapsulation to achieve both high Tg and low stress characteristics.

[For production]

By converting the resin composition of the present invention into a molding material and molding and curing it to encapsulate a semiconductor, a highly reliable encapsulated body can be obtained due to the following effects. I can do it.

1) High Tg because the matrix is formed by mutually compatible epoxy resin units and bismaleimide resin.
A cured product is obtained, and the durability rank reliability during solder immersion is greatly improved.

2) Polysiloxane domains having a flexible structure are minutely and uniformly dispersed in the matrix. - The elastic modulus of the cured resin decreases, resulting in a low stress cured product.

3) Since it contains an epoxy resin component, it has excellent adhesion to semiconductor IC surface lead frames, etc., and improves moisture resistance.

4) Since the polysiloxane component is introduced in the form of a bronch adduct with the epoxy resin, problems such as bleeding and thinning during molding are eliminated, and even better marking properties can be obtained.

[Effects of the Invention] Since the cured molding material using the encapsulating resin composition of the present invention has a high Tg, the encapsulated body has excellent solder crack resistance and reliability, has low stress, and has good temperature cycle resistance. This is an extremely effective resin composition for obtaining a sealed body with excellent properties.

Examples are shown below.

[Reference Example 1] 100 parts of an orthocresol novolac epoxy resin having an epoxy equivalent of 210 and a softening point of 70°C was heated at 170°C and stirred in a molten state.

A mixture of 2.5 parts of orthoallylphenol and 0.5 parts of 1,8-diazabicyclo[5,4,0]-7-undecene was added dropwise to this over 1 hour, and the reaction was then continued for 2 hours.

The allyl group-containing epoxy resin thus obtained had an epoxy equivalent of 223 and a softening point of 73°C.

100 parts of this allyl group-containing epoxy resin, 20 parts of toluene
0 part was heated to 80°C and stirred to form a homogeneous solution. To this, 1% by weight chloroplatinic acid iripropanol solution 0.6
After adding 50% of the N2 part, a hydrodiene dimethylpolysiloxane having an average degree of polymerization of 300 and having hydrogen groups only at both ends (hereinafter referred to as oil A) and a hydrodiene dimethylpolysiloxane having an average degree of polymerization of 40 and having hydrogen groups only at both ends. Siloxane (
A mixture of 18 parts of oil (hereinafter referred to as oil B) was added dropwise over 1 hour, and then the system was heated to 100°C and the reaction was continued for 3 hours.

After cooling, epoxy 5 is removed by eluting toluene under reduced pressure.
A block adduct (c) with a total of 280 and a softening point of 73°C was obtained.

[Reference example 2] 4.4゛-diaminodiphenylmethane (DM) 18
1 part was melted by heating at a bath temperature of 150 °C, and 82 parts of N,N'-4,4°-diphenylmethane bismaleimide (old B) was gradually added thereto while stirring and maintaining a suspended state. When the reaction solution becomes transparent after addition and does not lose its transparency even after cooling, the reaction is completed and the bismaleimide resin (
0) was obtained.

The resulting bismaleimide resin had a melting point of 100°C.

[Examples 1 to 2] With the composition shown in Table 1, the block adduct (C) obtained in Reference Example 1.2, the bismaleimide resin (D), a curing accelerator, silica powder, an aminosilane colorant, and a mold release agent were blended and kneaded with rolls to obtain a molding material. This was molded by transfer molding at iso''C for 13 minutes. The molded product was post-cured at 180° C. for 8 hours. Its properties are shown in Table 1.

[Comparative Example 1] A test was carried out by replacing the bismaleimide resin system (D) of Example 1 with a 1-borac type phenolic resin.

[Comparative Example 2] A test was carried out by replacing the block adduct (C) of Example I with an orthocresol type epoxy resin and replacing the bismaleimide resin (D) with a novolac type phenol resin.

Block adduct (C) and bismaleimide resin (D
) Examples 1 and 2 have a low elastic modulus and a glass transition point (
Tg) has been significantly improved.

*1 Set the piezoresistive element on the IC frame,
After transfer molding, the stress on the element was evaluated by the change in resistance value. After mounting a 4 x 7.5 ms element on a 216-bin lead frame, the molded body was transfer molded.
The treatment was repeated alternately for 30 seconds each in an atmosphere of 6°C and 200°C, and the occurrence of cracks on the surface of the molded product was observed after 300 cycles.

Claims (1)

[Claims] (1) (A) A polysiloxane to epoxy resin obtained by reacting a phenolborac epoxy resin partially containing an alkenyl group with a hydrogen organopolysiloxane represented by the following formula in the presence of a platinum catalyst. Block adduct ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ [In the formula, R_1R_2 is alkyl or Phenis group n is 5
represents an integer from 0 to 300] (B) A bismaleimide resin obtained by reacting bismaleimide and/or a derivative thereof with an aromatic diamine. (C) A sealing resin composition containing an inorganic filler as an essential component.