JPH01242616A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To provide the title compsn. having excellent curing characteristics and storage stability at ambient temp., by blending an epoxy resin having a plurality of epoxy groups with a nonvolak-type phenol resin curing agent, a specified microcapsulated curing accelerator and an inorg. filler. CONSTITUTION:This epoxy resin compsn. for sealing a semiconductor comprises an epoxy resin (A) having at least two epoxy groups in the molecule (e.g., an o-cresol novolak epoxy resin), a nonvolak-type phenol resin curing agent (B), a curing accelerator (C) enclosed in microcapsules made of a cured product of an epoxy resin having a dissolution temp. of 100-150 deg.C and having a skin thickness of 0.1-1mum and a particle diameter of 5-20mum (e.g., triphenylphosphine or 2-methyl-imidazole) and an org. filler (D) (e.g., silica) as the essential components. It is thereby possible to improve the storage stability of the compsn. as the curing accelerator is enclosed in microcapsules.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an epoxy resin composition for semiconductor encapsulation that has excellent curability and storage stability at room temperature.

[Prior art]

Generally, in epoxy resin compositions for semiconductor encapsulation, a curing accelerator is used to improve curing properties. For this reason, they have drawbacks such as poor fluidity when left at room temperature, and conventional methods have been to achieve both curability and storage stability by transporting or storing them at low temperatures.

However, transportation or storage at such low temperatures significantly increases costs. For this reason, it has been strongly desired to have both curability and storage stability at room temperature.

Hitherto, in order to achieve both curability and storage stability, research into latent curing accelerators has been actively conducted.

As a result, tetra-substituted phosphonium/tetra-substituted borates (Japanese Patent Publication No. 60-56172) and quaternary ammonium triazole compounds (Japanese Patent Publication No. 60-235828.
235830) etc. were proposed. However, it was impossible for any of these to achieve both curability and storage stability at room temperature.

[Purpose of the invention]

The present invention was developed with the aim of achieving both curability and storage stability at room temperature, which was impossible with conventional technology.As a result of research, we found that storage stability could be improved by microcapsulating the curing accelerator. Based on this knowledge, various studies have been carried out and the present invention has been completed.

[Configuration of the Invention] The present invention provides (A) an epoxy resin having at least two epoxy groups in one molecule, (B) a novolac type phenolic resin curing agent, and (C) an epoxy resin curing having an elution temperature of 100 to 150'C. The thickness of M is 0.1=IIIm, and the particle size is 5~
The present invention relates to an epoxy resin composition for semiconductor encapsulation, which is characterized in that it contains as essential components a curing accelerator (D) and a filler encapsulated in microcapsules having a diameter of 20 μm.

The epoxy resin composition referred to in the present invention essentially contains an epoxy resin, a curing agent, a microencapsulated curing accelerator, and an inorganic filler, and optionally adds 1111 fuel, processing agent, 11114, mold release agent, and others. It is a combination of agents.

Epoxy resins refer to all types of resins having epoxy groups, and include common names such as bisphenol type epoxy resins, novolac type epoxy resins, and heterocyclic type epoxy resins.

The curing accelerator of the present invention refers to the following, and it is essential that it is microencapsulated with a cured epoxy resin.

Regarding microcapsules, the particle size and shell thickness are technically important points.

Examples of the curing accelerator include diazabicycloundecene, triphenylphosphine, 2methylimidazole, and dimethylbenzylamine.

The material forming the shell of the microcapsule is a cured epoxy resin and has an elution temperature of lo.

~150°C is preferred. The elution temperature here refers to the temperature at which the microencapsulated curing accelerator elutes to the outside through the shell or elutes to the outside when the shell is destroyed.In other words, curing is accelerated during mixing and kneading of the composition. Epoxy resin is preferably used as the material constituting the shell, and is preferably one in which the curing accelerator does not dissolve out during molding and thereby brings out the catalytic action of the curing accelerator. Materials other than epoxy resin, such as melamine resin and phenol resin, can be considered, but these may affect moisture resistance, or may not affect curability depending on the amount added.

Furthermore, if the material 4 is other than epoxy resin, it will be a foreign substance to the epoxy resin composition for encapsulating a semiconductor, and there is a great possibility that it will adversely affect the moldability and physical properties after encapsulating the semiconductor.

Furthermore, the thickness of the wall material is preferably 0.1 to 1 μm.
O, l/7m) 1 and the curing accelerator will be eluted during mixing and kneading. Moreover, if the thickness is more than 1 μm, the curing accelerator will not be eluted during molding.The particle size of the microcapsules is preferably 201 JIl or less. When the particle size is larger than 20 μm, dispersibility deteriorates and curing becomes uneven, and when the particle size becomes larger, the capsule strength tends to inevitably become weaker. The amount of curing accelerator to be added is preferably 0.1 to 0.5% by weight, because if it is added in a small amount or more than necessary, the desired curability cannot be obtained.

Examples of the microencapsulation method include an interfacial precipitation method, an interfacial polymerization method, and an in-liquid hardening film method.

(Effects of the Invention) According to the present invention, it is possible to obtain an epoxy resin composition that is excellent in curability and storage stability at room temperature, which were not compatible with the conventional technology, while utilizing the conventional technology as is.Especially for semiconductor encapsulation applications. Nowadays, it is expected that more and more plastic packaging will be used in the future, and therefore, it is desired to have both hardenability and storage stability at room temperature, and the present invention plays a very important role in industry.

〔Example〕

(Manufacture of microcapsules) The particle size of triphenylphosphine and/or 2-methylimidazur as a curing accelerator is 20. The amount of epoxy resin is such that the coating thickness of the curing accelerator is 0.1 to 1. Appropriate adjustments were made to obtain Oμ sardines.

This dispersion was emulsified and dispersed in a solution in which phenol novola resin was similarly dissolved in a diluent as a curing agent for epoxy resin, and the mixture was heated to 100°C while stirring to remove xylene from the system. Microcapsules of the curing accelerator having the compositions shown in Table 1 were produced by filtering and drying to obtain microcapsules.

Table 1 (Examples 1 to 3, Comparative Examples 1 to 3) Orthocresol novolak epoxy resin 20 parts by weight Phenol novolac 10 parts by weight Fused silica 70 parts by weight Alicyclic epoxy silane 0.5 parts by weight Carbon blank
0.5 parts by weight Montanic acid wax
0.5 parts by weight The microencapsulated curing accelerator shown in Table 1 was added to the above composition in an amount of 0.2 parts by weight, and mixed uniformly using a blender.
The mixture was kneaded for 3 minutes with a hot roll at 0°C to obtain six types of epoxy resin compositions for semiconductor encapsulation having the combinations shown in Table 2.

Table 2 shows the results of testing the storage stability and curing properties of these molding materials.

(Comparative Examples 4 to 6) In the composition of the example, the curing accelerator shown in Table 2 was directly added without using the microencapsulated curing accelerator, mixed uniformly, and kneaded with a hot roll at 100°C for 3 minutes. An epoxy resin composition for semiconductor encapsulation was obtained.

Table 2 shows the results of testing the storage stability and curing properties of these molding materials.

Claims (1)

[Claims] (1) (A) Epoxy resin having at least two or more epoxy groups in one molecule (B) Novolak type phenolic resin curing agent (C) Consisting of a cured epoxy resin with an elution temperature of 100 to 150°C and a shell thickness of 0.1 to 1 μm, and the particle size is 5 to 1 μm.
An epoxy resin composition for semiconductor encapsulation, characterized in that it contains as an essential component a curing accelerator (D) inorganic filler encapsulated in microcapsules having a diameter of 20 μm.