JPH10182831A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin compsn. having an excellent moldability (e.g. filling property and freeness from internal voids) in forming thin packages, and also excellent crack resistance to the soldering. SOLUTION: This compsn, comprises a polytetrahydrofuran/ polydimethylsiloxane/polytetrahydrofuran block terpolymer of the following general formula (wherein R is hydrogen, methyl or a cyclic onium, and m and n are each 30 to 150), an epoxy resin, a phenolic resin curing agent, an inorg. filter and a curing accelerator as indispensable components. This compsn. preferably contains 0.1 to 3wt.% based on the whole compsn., polymer of the formula.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation which is excellent in package filling, internal voids, and solder crack resistance in a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are sealed with a thermosetting resin composition. In particular, in an integrated circuit, an ortho-cresol novolac epoxy having excellent heat resistance and moisture resistance is used. An epoxy resin composition (hereinafter referred to as a resin composition) in which a resin is cured with a phenol novolak resin and an inorganic filler such as fused silica or crystalline silica is blended as a filler is used. However, in recent years, chips have become larger and larger as integrated circuits have become more highly integrated, and packages have become smaller and thinner QFPs, SOPs, SOJs, and surface-mounted packages than conventional DIP types.
It is changing to TSOP, TQFP, PLCC, etc.
In other words, a large chip is sealed in a small and thin package, and problems such as pad shift during molding, unfilled voids, internal voids, and cracks during mounting have been greatly highlighted. Therefore, development of a resin composition that solves these problems is desired.

[0003]

SUMMARY OF THE INVENTION The present invention solves such a problem by using a triblock copolymer of the formula (1) to improve the flowability of the resin composition and to reduce the consumption of the resin composition. Due to the bubble effect, there are few internal voids, excellent filling in thin packages, improved adhesion to lead frames and semiconductor chips, etc., and reduced stress due to low elasticity of molded products at high temperatures, And to provide a resin composition having improved solder crack resistance.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a (A) polytetrahydrofuran (hereinafter referred to as PTHF) -polydimethylsiloxane (hereinafter referred to as PDMS) -polytetrahydrofuran terpolymer copolymer of the formula (1). , (B) an epoxy resin, (C) a phenolic resin curing agent, (D) an inorganic filler, and (E) a curing accelerator.
Compared with the conventional resin composition, it has characteristics excellent in moldability, solder crack resistance and the like.

Embedded image (R is hydrogen, a methyl group, or a cyclic onium salt. M, n
= 30-150)

[0005]

DETAILED DESCRIPTION OF THE INVENTION The triblock copolymer of PTHF-PDMS-PTHF represented by the molecular structure of formula (1) used in the present invention is a crystalline polymer, PTH.
Since it contains F, it is solid at normal temperature, but melts at a kneading temperature of 70 to 100 ° C. during the production of the resin composition, so that it is uniformly dispersed in the resin composition and improves the fluidity during molding. Furthermore, the cured product of the resin composition containing this polymer has a characteristic that low elasticity due to PDMS is exhibited at low temperatures and low elasticity due to PTHF at high temperatures. R in the formula (1) is
Hydrogen, a methyl group, or a cyclic onium salt is particularly preferable, and a cyclic onium salt type is particularly preferable.A cyclic onium base reacts with a phenolic hydroxyl group and is fixed, so that a stain or molding on a mold is caused. It has the characteristic of not causing spots on objects. Preferably, the cyclic onium base is bonded to one or both ends. The ternary block copolymer polymer of the formula (1) has better adhesion than silicone oil which is a conventionally used low stress agent,
High defoaming effect. M and n in the formula (1) are each 30 to 15
0, and when m and n are less than 30, the adhesiveness is reduced.
When n exceeds 150, the viscosity increases and the fluidity decreases. or,
The compounding amount of the formula (1) is 0.1 to 0.1 in the total resin composition.
3% by weight is preferred. If the amount is less than 0.1% by weight, internal voids and the like are generated, and the formability decreases. If the amount exceeds 3% by weight, the solder crack resistance decreases.

[0006] The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having an epoxy group. For example, a biphenyl-type epoxy compound, a bisphenol-type epoxy compound, a phenol novolak-type epoxy resin, a cresol novolak-type epoxy resin, a triphenolmethane-type epoxy compound, an alkyl-modified triphenolmethane-type epoxy compound, and a triazine nucleus-containing epoxy resin are exemplified. However, the present invention is not limited to these.

The phenol resin curing agent used in the present invention includes, for example, phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol resin, xylylene-modified phenol resin, terpene-modified phenol resin, triphenolmethane compound and the like. Particularly, a phenol novolak resin, a dicyclopentadiene-modified phenol resin, a xylylene-modified phenol resin, and a terpene-modified phenol resin are preferable. In addition, the ratio of the epoxy group of the epoxy resin to the phenolic hydroxyl group of the phenol resin curing agent is preferably 0.9 to 1.3. And the mold release failure occurs.

As the curing accelerator used in the present invention, any one can be used as long as it promotes the curing reaction between the epoxy group and the phenolic hydroxyl group, and those generally used for a sealing material can be widely used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, dimethylbenzylamine, 2-methylimidazole and the like are used, and these are used alone or in combination.

As the inorganic filler used in the present invention, those generally used for a sealing material can be widely used. The blending amount of the inorganic filler is 80 in the total resin composition.
When the content is less than 80% by weight, the solder crack resistance is reduced. When the content is more than 90% by weight, the fluidity is reduced, and molding failure occurs.

The resin composition of the present invention comprises, in addition to the components (A) to (E), if necessary, a silane coupling agent, a brominated epoxy resin, a flame retardant such as antimony trioxide, hexabromobenzene, and carbon black. , Colorants such as bengalara,
Various additives such as a release agent such as natural wax and synthetic wax and a low stress additive such as silicone oil and rubber can be blended. The resin composition of the present invention,
After sufficiently homogenizing the components (A) to (E) and other additives using a mixer or the like, the mixture is further melt-kneaded with a hot roll or a kneader, cooled, and pulverized. These resin compositions can be used for covering, insulating, encapsulating, etc. electrical components or electrical components such as transistors and integrated circuits.

Hereinafter, the present invention will be described specifically with reference to examples. Example 1 1.0 part by weight of a polymer of the formula (2) (m = 48, n = 95)

Embedded image Biphenyl type epoxy compound (melting point: 95 ° C., epoxy equivalent: 195 g / eq) 5.4 parts by weight Paraxylene-modified phenol resin (softening point: 70 ° C., hydroxyl equivalent: 175 g / eq) 4.9 parts by weight Fused spherical silica powder (average particle diameter) 20 μm, maximum particle size 75 μm) 87.0 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0.2 part by weight Carbon black 0.3 part by weight Carnauba wax 1.2 Parts by weight were mixed at room temperature with a mixer, kneaded at 70 to 100 ° C. using a biaxial roll, cooled and pulverized to obtain a resin composition, which was formed into tablets. About the obtained resin composition, it evaluated by the method shown below. Table 1 shows the results.

Evaluation method Spiral flow: Measurement was performed using a mold for measuring spiral flow according to EMMI-I-66 at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² and a curing time of 2 minutes. Internal void: Using a low pressure transfer molding machine, 17
5 ° C., 100 kg / cm ² , curing time 2 minutes, 160p
The QFP was sealed, and the obtained package was measured using an ultrasonic flaw detector to count voids of 0.3 mm or more on the internal island. Solder crack resistance: Using a low-pressure transfer molding machine, at 175 ° C., 100 kg / cm ² , and curing time of 2 minutes.
A 9 mm × 9 mm chip was sealed in 80 pQFP. The test device was tested under the environment of 85 ° C. and 85% relative humidity.
Treated for 20 and 160 hours, then IR at 240 ° C
Soldering was performed with a reflow device, and internal cracks were observed using an ultrasonic flaw detector.

Examples 2 and 3, Comparative Examples 1 and 2 Resin compositions were prepared in the same manner as in Example 1 according to the formulations shown in Table 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. The structure of the polymer of formula (1) used in Example 3 is shown in formula (3) (m = 74, n = 102).

Embedded image

The silicone oil used in Comparative Example 2 is a polyoxyalkylene-modified silicone oil.

[Table 1]

[0015]

According to the present invention, it is possible to solve molding defects such as unfilling and internal voids in a thin package, and furthermore, the solder cracking resistance is not reduced, and the moldability and the soldering resistance, which have been contradictory to each other, have been reduced. Cracking properties can be compatible.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 61/04 C08L 61/04 63/00 63/00 83/10 83/10 H01L 23/29 H01L 23/30 R 23/31

Claims (3)

[Claims] 1. A polytetrahydrofuran-polydimethylsiloxane-polytetrahydrofuran triblock copolymer polymer of the formula (1), (B) an epoxy resin, (C) a phenol resin curing agent, and (D) an inorganic filler. Timber,
And (E) an epoxy resin composition for semiconductor encapsulation comprising a curing accelerator as an essential component. Embedded image (R is hydrogen, a methyl group, or a cyclic onium salt. M, n
= 30-150) 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the polymer of the formula (1) is contained in an amount of 0.1 to 3% by weight in the total epoxy resin composition. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein one or both terminals of the polymer of the formula (1) is a cyclic onium salt type.