JPH06184283A - Resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent curability and storage stability by using a specific epoxy resin, a specific microcapsule, a novolak phenolic resin hardener and an inorganic filler as essential components. CONSTITUTION:This resin composition contains, as essential components, (A) an epoxy resin having >=2 epoxy groups in one molecule, e.g. biphenyl-type epoxy compound, (B) a novolak-type phenolic resin hardener, (C) preferably 0.1-0.5wt.% (based on the total composition) of a microcapsule having a releasing temperature of 100-150 deg.C and produced by encapsulating a cure accelerator with a capsule base composed of an acrylic rubber and an inorganic composite material and (D) preferably 70-90wt.% of an inorganic filler such as fused silica powder.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an epoxy resin composition for semiconductor encapsulation which is excellent in curability and storage stability at room temperature.

[0002]

2. Description of the Related Art Generally, in a semiconductor encapsulating epoxy resin composition, a curing accelerator is used in order to improve curability. For this reason, there are drawbacks such as poor fluidity when left at room temperature. Usually, both curability and storage stability have been achieved by transporting at low temperature or storing at low temperature. However, transportation or storage at such a low temperature significantly increases the cost. Therefore, it has been strongly desired to achieve both curability and storage stability at room temperature. Conventionally, in order to achieve both curability and storage stability, research on latent curing accelerators has been actively conducted. As a result, tetra-substituted phosphonium tetraborates (Japanese Patent Publication No. 60-56172), quaternary ammonium triazolate compounds (Japanese Patent Publication No. 60-235828, Japanese Patent Publication No. 60-235830).
No. gazette) was proposed. However, it was impossible to achieve both curability and storage stability at room temperature.

[0003]

The present invention was studied for the purpose of achieving both curability and storage stability at room temperature, which were not possible with the prior art, and as a result, storage stability was improved by encapsulating a curing accelerator. The present invention has been completed by obtaining the knowledge that the property is improved, and further advancing various researches based on this knowledge.

[0004]

The present invention provides (A) an epoxy resin having at least two epoxy groups in one molecule, (B) a novolac type phenol resin curing agent, (C).
A microcapsule having an elution temperature of 100 to 150 ° C., which is obtained by encapsulating a curing accelerator in a capsule base material made of acrylic rubber and an inorganic composite, and (D) an inorganic filler resin composition for semiconductor encapsulation. It is a thing.

The epoxy resin used in the present invention refers to all epoxy resins having at least two epoxy groups in one molecule. What is normally used for the resin composition for semiconductor encapsulation may be used, for example, a biphenyl type epoxy compound, a bisphenol type epoxy compound, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a triphenolmethane type epoxy compound, an alkyl modification. Examples thereof include, but are not limited to, triphenolmethane type epoxy compounds and triazine nucleus-containing epoxy resins.

The novolac type phenolic resin curing agent used in the present invention may be any one which is usually used in a resin composition for semiconductor encapsulation, and examples thereof include phenol novolac resin, cresol novolac resin, dicyclopentadiene modified phenolic resin and para-novolac resin. Examples thereof include, but are not limited to, a xylene-modified phenol resin, a naphthol-modified phenol resin, a condensate of phenols with benzaldehyde or naphthylaldehyde, and a triphenolmethane compound. Further, it is preferable to mix these curing agents so that the epoxy equivalent of the epoxy resin and the hydroxyl equivalent of the novolac type phenol resin curing agent are matched.

The microcapsules used in the present invention are coated with a curing accelerator in a capsule base material composed of acrylic rubber and an inorganic composite, and it is essential that the elution temperature is 100 to 150 ° C. The inorganic composite, which is one component of the capsule base material, is a common inorganic filler, fused silica,
Examples include crystalline silica and silicon nitride. Examples of the curing accelerator include triphenylphosphine, diazabicycloundecene, triphenylphosphine, 2-methylimidazole, dimethylbenzenamine and the like.

As the capsule base material other than the acrylic rubber and the inorganic composite, materials such as melamine resin and phenol resin are conceivable. However, these affect the moisture resistance or the curability depending on the added amount. It may cause adverse effects, which is not preferable. Regarding the microcapsules, the thickness of the particle size is an important technical point. The particle size of the microcapsules is preferably 20 μm or less. Two
If it exceeds 0 μm, the dispersibility is poor and uneven curing occurs. Further, the shell thickness of the capsule base material is preferably 0.5 to 5 μm. If it is less than 0.5 μm, the curing accelerator will be eluted during mixing and kneading. If it exceeds 5 μm, the curing accelerator does not elute during molding. The elution temperature as used herein means the temperature at which the microcapsule-cured curing accelerator is eluted to the outside through the shell or is destroyed by breaking the shell.

That is, it is preferable that the curing accelerator does not elute at the time of mixing and kneading the composition, and the catalytic action of the curing accelerator is brought out by elution at the time of molding. Furthermore, if it is a material other than the epoxy resin, it is different from the epoxy resin composition for semiconductor encapsulation and is a foreign substance, and there is a great possibility that the moldability and the physical properties after semiconductor encapsulation are adversely affected.
As the microencapsulation method, an interfacial precipitation method,
There is an interfacial polymerization method, in which a curing accelerator is encapsulated in a capsule base material in which an acrylic rubber is premixed with an inorganic composite material to encapsulate it. The inorganic composite in the capsule here is 30 to 9 based on the total amount of the acrylic rubber and the inorganic composite.
0% is good, and if it is less than 30%, the curing accelerator easily elutes at 100 to 150 ° C. If it exceeds 90%, it becomes difficult to encapsulate the curing accelerator. The addition amount of the curing accelerator is preferably 0.1 to 0.5% by weight in the total amount of the epoxy resin composition. Outside of this range, the desired curability cannot be obtained.

Examples of the inorganic filler used in the present invention include fused silica powder, spherical silica powder, crystalline silica powder, secondary agglomerated silica powder, porous silica powder, alumina and the like, and particularly fused silica powder and spherical silica powder. , And a mixture of fused silica powder and spherical silica powder are preferred. Further, the blending amount of the inorganic filler is preferably 70 to 90% by weight based on the total amount of the resin composition in view of the balance between solder crack resistance, moldability and fluidity.

The resin composition of the present invention contains an epoxy resin, microcapsules, and an inorganic filler as essential components.
In addition to these, silane coupling agents, brominated epoxy resins, flame retardants such as antimony trioxide and hexabromene, colorants such as carbon black and red iron oxide, mold release agents such as natural wax and synthetic wax, and silicones as required. Various additives such as low stress additives such as oil and rubber may be appropriately blended.

Further, in order to produce the resin composition for semiconductor encapsulation of the present invention as a molding material, epoxy resin, microcapsules, inorganic fillers and other additives are sufficiently uniformly mixed with a mixer or the like, Further, it can be melt-kneaded with a hot roll or a kneader, cooled, and then pulverized to obtain a sealing material. These molding materials are used to coat and insulate transistors, integrated circuits, etc., which are electrical or electronic components.
It can be applied to sealing and the like.

The present invention will be specifically described below with reference to examples. Examples 1 and 2 Orthocresol novolac epoxy resin (softening point 65 ° C., epoxy equivalent 200) 20 parts by weight Phenol novolac resin (softening point 95 ° C., hydroxyl equivalent 104) 10 parts by weight fused silica 70 parts by weight Alicyclic epoxysilane (A-186 manufactured by Nippon Unicar Co., Ltd.) 0.5 parts by weight Carbon black 0.5 parts by weight Carnauba wax 0.5 parts by weight The microcapsulated curing accelerator shown in Table 1 was 0.2 parts by weight. The mixture was added as described above and uniformly mixed using a blender, and then kneaded with a hot roll at 100 ° C. for 3 minutes to obtain 6 kinds of epoxy resin compositions for semiconductor encapsulation in the combinations shown in Table 2. Table 2 shows the evaluation results of the storability and curability of these molding materials.

Evaluation method Curability: JIS K6911 (Bacol hardness of the molding after molding the molding material at 175 ° C. and 10 seconds after mold opening) Storability: When the molding material was stored at 40 ° C., the spiral flow was initially set. 10% less than the number of days)

Comparative Examples 1 to 7 Epoxy resin compositions for semiconductor encapsulation were obtained in the same manner as in the examples, except that triphenylphosphine was used instead of the microencapsulated curing accelerator. . Table 2 shows the evaluation results of the storability and curability of these molding materials.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

According to the present invention, it is possible to obtain an epoxy resin composition for semiconductor encapsulation which utilizes the conventional technique as it is and is excellent in curability and storage stability at room temperature, which were not compatible with the conventional technique. In semiconductor encapsulation applications, plastic packaging has been increasingly advanced, and therefore epoxy resin for semiconductor encapsulation, which has both curability and storage stability at room temperature, is very useful in industry.

Claims (1)

[Claims] 1. Accelerating curing with (A) an epoxy resin having at least two epoxy groups in one molecule, (B) a novolac-type phenol resin curing agent, and (C) a capsule base material composed of an acrylic rubber and an inorganic composite. A microcapsule having an elution temperature of 100 to 150 ° C., which is formed by encapsulating the agent, and
(D) A resin composition for semiconductor encapsulation, which comprises an inorganic filler as an essential component.