JPS6386716A - Epoxy resin composition for semiconductor sealing - Google Patents

Abstract

PURPOSE:To provide the titled composition outstanding in moldability, moisture resistance after thermal shock and crack resistance, containing solid silicone rubber coated with liquid synthetic rubber having reactive functional group. CONSTITUTION:The objective composition containing solid silicone rubber (pref. with a melting point equal to the decomposition temperature for the siloxane linkage and molecular weight >=20,000, e.g., dimethyl polysiloxane, phenylmethyl polysiloxane) coated with liquid synthetic rubber having reactive functional group (e.g., epoxy group, vinyl group, carboxyl group) (pref., with the functional group being epoxy group and molecular weight 700-3,000).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides improvements in moldability, moisture resistance (especially moisture resistance after thermal shock),
This is an epoxy resin composition for semiconductor encapsulation that has excellent crack resistance, and its feature lies in the addition of a synthetic rubber/silicone composite material that has a wide stress absorption range.

[Prior art]

Conventionally, methods using synthetic rubbers and silicones have been known as techniques for reducing stress in semiconductor encapsulation compositions.

However, there were problems with moldability, moisture resistance, etc.

For example, a method using synthetic rubber (Japanese Unexamined Patent Publication No. 53-144
958.57-180626.58-174416), there was a problem with the generation of paris during molding due to elution of synthetic rubber, and methods using silicones (Japanese Patent Laid-Open No. 56-129)
246.58-47014''), deterioration of moisture resistance was a problem due to the water permeability of silicone.

In addition, the conventional technology has both advantages and disadvantages in terms of moisture resistance after thermal shock, and cannot satisfy the demands of the market. No technology has been established that can equally satisfy both rapid thermal shocks such as solder immersion and relatively gentle thermal shocks such as thermal shocks in the gas phase.

[Purpose of the invention]

The present invention improves moldability and moisture resistance (
As a result of our research to improve the moisture resistance (especially moisture resistance after thermal shock), we found that the problem could be solved by combining and integrating the features of synthetic rubber and silicone.Based on this knowledge, we proceeded with various research. This has led to the completion of the present invention.

[Structure of the invention]

The present invention is an epoxy resin composition for semiconductor encapsulation characterized by containing a solid silicone rubber whose surface is coated with a liquid synthetic rubber having a reactive functional group.

The epoxy resin composition referred to in the present invention includes a modified mexi resin, a curing accelerator, and a silicone rubber coated with synthetic rubber (hereinafter referred to as a composite low stress additive), and generally contains a curing agent. - Fillers, surface treatment agents, mold release agents, pigments, II fuel, etc. are often added.

Engineering resin refers to all types of epixy resins such as bisphenol type, phenol novolac type, cresol novolak type, and heterocyclic type epixy resin.

A curing accelerator refers to a catalyst that cures an epixy resin, and examples thereof include imidazoles, tertiary amines, organic phosphites, and organic aluminums.

Further, for semiconductor encapsulation, it is preferable to use a material with few impurities, for example, one having an extracted water conductivity of 10 or less when 5 tons of resin is extracted with 459 pure water at 125° C. for 20 hours.

It is essential that the composition of the present invention contains a composite low stress additive. As the liquid synthetic rubber, it is necessary to use one or more synthetic rubbers having reactive functional groups (for example, epoxy groups, vinyl groups, carboxyl groups) and to react and immobilize them on the surface of the solid silicone rubber. Trade names of liquid synthetic rubbers include R-45 series (Idemitsu Petrochemicals), Nl5SO-FB series (Japan 1st difference), 8-stone polybutadiene series (Nippon Petrochemicals), and the like. In particular, the functional group is an epoxy group and the molecular weight is 700.
~3000 liquid synthetic rubber is preferred.

Solid silicone rubber is a cross-linked silicone colimer whose melting point is the decomposition temperature of siloxane bonds and whose molecular weight is 2.
It is more than 10,000. Common names are dimethylcolisiloxane, phenylmethylpolysiloxane, etc. Commercially available manufacturers include Toshiba Silicone, Toray Silicone, and Shin-Etsu Chemical. In addition, as for the particle size of the solid silicone rubber, it is preferable that the maximum particle size is 50 #l or less h0.As for the composite technology of liquid synthetic rubber and solid silicone rubber, the catalyst, reaction conditions (temperature), and dispersion conditions are is India.

The catalyst is preferably uncatalyzed or the same as the curing accelerator of the composition.

Further, the amount of the composite low stress additive added is preferably 0.5 to 5% by weight.

〔Effect of the invention〕

Original F! Complying with IJE makes it possible to supply epixy resins for semiconductor encapsulation with excellent moldability, moisture resistance, and crack resistance to the market.

The company supplies plastic-encapsulated semiconductors that do not have any problems even under severe mounting conditions such as solder immersion, and will further promote the general use of semiconductors that can be mass-produced and at lower costs.

〔Example〕

The following is an explanation using a study example of a molding material for semiconductor encapsulation. All parts used in the study examples are parts by weight, and the raw materials used are as follows.

Egoxy resin Epicoat 180S65 Yuka Shell Exoxy Hardening Agent Phenol Novolak Tensei Bakelite Hardening Accelerator Subaki Tamea D
Susumu Chemical Industry Filler Heguzu Rex Ryu Mori Surface Treatment Agent A-189 Nippon Unicar Mold Release Agent Hoechst Wax E Hoechst Jano ξn Composite Low Stress Additive ■～■ Table 1 Comprehensive Table -1 Examination Example 1 ~7 20 parts of epixy resin, 10 parts of curing agent, 2 parts of curing accelerator α, 5 parts of surface treatment agent, 0.5 part of mold release agent, low stress additive X
and 70-x parts of filler were mixed as shown in Table 2 to obtain seven types of molding materials. What are the results of evaluating the moldability, moisture resistance, and crack resistance of these materials? ! -2, the use of the composite low stress additive of the present invention shows outstanding properties.

Claims (1)

[Claims] An epoxy resin composition for semiconductor encapsulation, comprising a solid silicone rubber whose surface is coated with a liquid synthetic rubber having a reactive functional group.