JPS6281446A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent moisture resistance after thermal stress and suitable for use in sealing semiconductors, by adding a specified silica filler and synthetic rubber. CONSTITUTION:An epoxy resin is blended with silica having a weight-average particle size of 15mu or below and the max. particle size of 100mu or below as a filler, 0.1-20wt% synthetic rubber contg. at least two epoxy groups per molecule (e.g., 1,4-trans polybutadiene contg. epoxy groups at both terminals), a hardener, a curing accelerator, a parting agent, a flame retarder, a pigment, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a synthetic resin composition for semiconductor encapsulation, which has excellent moisture resistance after heat stress.

Its characteristics are: The aim is to reduce stress during papermaking by using synthetic rubber containing xyl groups and fillers with small particle sizes.

[Prior art]

Conventional engineered poxy resin compositions for semiconductor encapsulation have generally used silips with a maximum particle size of 150ξcm and an average particle size of about 20 microns, but the thin flannel cage caused filling failures in 9+ LSIs. I was waking up Sennari, who was cracked in the cage. Also, with the recent movement toward surface mounting on substrates, thin IC's? After the rcA cage is temporarily attached to the substrate, it is immersed in a deposition tank and subjected to heat stress as the rcA cage is directly immersed in solder at a temperature of 250 to 350°C. This rapid thermal stress creates gaps between the IC bellet and the resin, and between the lead frame and the resin, and the moisture resistance of the rounded product is significantly deteriorated. There was no material with excellent moisture resistance after this heat stress.

On the other hand, although various studies have been made on low-density Crab I xy resin compositions using synthetic rubber, there have been problems with moldability (particularly curability, moldability, and mold releasability). For example, when a carboxyl group-containing diene-based rubbery polymer is added [JP-A-58-176958], not only does the rubber elute and formability is problematic, but it also contains a hydrophilic carboxyl group, so Moisture resistance was poor. Diene rubbers that have two or more I-oxy groups in their molecules do not elute because they bond with epoxy resins through chemical reactions, but this rubber alone cannot improve moisture resistance after heat stress. Not enough.

[Purpose of the invention]

The present invention was developed as a result of research aimed at developing practical products by fundamentally improving epoxy resin compositions for semiconductor encapsulation, which conventionally had problems with moisture resistance after being subjected to heat stress. The present inventors have discovered that by adding a synthetic rubber containing an eixy group together, an eixy resin composition for semiconductor encapsulation with excellent moisture resistance after heat stress can be obtained.

[Structure of the invention]

The present invention uses silica with a weight average particle size of 15 microns or less and a maximum particle size of 100 microns or less as a filler, and uses synthetic rubber containing two or more engineered poxy groups in the molecule, from 01 to
This is an epoxy resin composition for semiconductor encapsulation characterized by containing 20 tf'%.

In general, an engineered poxy resin composition for semiconductor encapsulation includes an epoxy resin, silica, a processing agent, a curing agent, a curing accelerator, a mold release agent,
Composed of flame retardants, pigments, etc. Currently, the commonly used materials are cresol novolac-type eixy resin, phenol novolac (curing agent), tertiary amine (curing accelerator), silica (filler), and silane cassillating agent ( silica surface treatment agent), etc. The amount of silica is usually 50 to 80% by weight.

In the present invention, it is necessary for the silica to have a weight average particle size of 15 microns or less and a maximum particle size of 100 microns or less, and if it is larger than this, there is no effect on moisture resistance after heat stress. Flat no! For thin-walled wood cages, it is preferable to use particles with even smaller particle sizes, such as those with a weight average particle size of 10 microns or less and a maximum particle size of 50 microns or less.

The synthetic rubber must contain 01 to 20% by weight of synthetic rubber containing two or more eixyx groups in the molecule. Synthetic rubbers that do not have two or more epoxy groups in the molecule have poor affinity with epoxy resins and may cause problems such as bleeding during molding, and if the amount added is less than 0.1% by weight, there is no effect and 20% is In the above additive lid, the strength of the resin is significantly 1. <Decrease 17
In addition, the thermal expansion coefficient and dimensional change rate are large, and the moisture resistance after heat stress is not effective.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an epoxy resin composition for semiconductor encapsulation that has excellent moisture resistance after heat stress. In semiconductor encapsulation applications, the resin of the present invention, which has excellent moisture resistance after heat stress, is suitable for semiconductor encapsulation applications, where the volume occupied by XC-:lets in the entire node increases due to the development of ultra-LSIs, and the resin wall thickness becomes thinner. The composition is very advantageous in that it provides a high degree of reliability.

〔Example〕

Below is Engineering 4! This will be explained using a study example of a resin composition. All parts used in the examples are parts by weight.

Examples 1-4 The silica used in this example is as follows.

Fused Silica A (Denki Kagaku Kogyo) Weight average particle size 10 microns Maximum particle size 70 microns Fused Silica B (1! Ki Kagaku Kogyo) Weight average particle size 7 microns Maximum particle size 50 microns Crystalline Silica C (Tatsumori) Weight average particles Diameter: 10 microns Maximum particle size: 70 microns The synthetic rubber containing eixyl groups used in this example has the following structure.

Synthetic rubber a: 1,4 trans type polybutadiene containing engineered epoxy groups at both terminals (1i 1450 per epoxy) Synthetic rubber b: Synthesis of 1,4 trans type polybutadiene containing epoxy groups in the molecule (number average molecule III 3000, epoxy equivalent 200) Rubber C
: Internally engineered 1,2 vinyl type polybutadiene containing I xyl group (number average molecular weight 700, epoxy equivalent 220) Synthetic rubber d: 1.2 vinyl type polybutadiene containing internal epoxy group (number average molecular weight 1000, epoxy equivalent 190) Synthetic rubber e: 1.2 vinyl type butadiene containing epoxy groups in the molecule (number average molecular weight 1800, epoxy group II!: 220) Examples 1~
9 70 parts of IJ Force A-C, 0.4 parts of Table i#r treatment agent (Nippon Unicar A-186), parts of synthetic rubber a-e X,
x H? Xyresin (Sumitomo Chemical KSCN-1025) 2
0-X part, phenol novolac (Sumitomo Bakelite)
10 parts, curing accelerator (KAI Kasei PP-360/Shikoku Kasei 2MZ = 9/1) 0.2 parts, pigment (Mitsubishi Kasei) 11.5 parts, mold release agent (Hoechst Jano ξn Hoechst OP/Hoechst S = 1 /1) 0.4 part was added and kneaded in a ridge co-kneader to obtain nine types of niboxy resin compositions.

The results of measuring the moisture resistance and moldability of these molding materials after heat stress were found to be superior to those of the comparative examples as shown in the table.

Comparative Example 1 Terminal carboxyl group, 1f Liisozolene (Kuraray LIR
-403') 12 parts of synthetic rubber was added to synthetic rubber B- in the example.
The same raw materials as in Example were used in place of No. 6.

Comparative Example 2 Fused silica D (Tatsumori) with a weight average particle diameter of 20 microns and a maximum particle diameter of xso microns was used in place of the silica A-C in the examples, and the other raw materials were the same as in the examples.

Comparative Example 3 Fused silica D (Tatsumori) with a weight average particle size of 20 microns and a maximum particle size of 150 microns was used in place of the silica A-C in the examples, and the synthetic rubber in the examples was not added at all. The same raw materials as in the examples were used.

*1.16 pin When molding DIP, determine the degree of paris on the lead bin when the distance to a part of the tie bar is less than h: A, 2, 1, 6: B, station ~ -: C1h or more (tie bar) ) Do *2, 1 6 pin DI with aluminum simulated element sealed
P was immersed in a solder bath at 280°C for 5 seconds, and then heated to 135°C.
Stored for 500 hours at ℃ and 100% RH, and judged based on the number of defects due to aluminum corrosion/total number.

Claims (1)

[Claims] It is characterized by using silica with a weight average particle size of 15 microns or less and a maximum particle size of 100 microns or less as a filler, and containing 0.1 to 20% by weight of synthetic rubber containing two or more epoxy groups in the molecule. An epoxy resin composition for semiconductor encapsulation.