JPH0739471B2 - Sealing resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a resin composition for encapsulation which is used for encapsulation of electronic / electrical parts and the like having low stress and excellent crack resistance.

(Prior Art) Conventionally, a method of sealing an electronic component such as a diode, a transistor, or an integrated circuit with a thermosetting resin has been performed. This resin encapsulation is economically advantageous as compared with the hermetic sealing method using glass, metal, or ceramic, and is therefore widely used. Among thermosetting resins used as sealing resins, epoxy resins are most commonly used. Acid anhydrides, aromatic amines, novolac type phenolic resins and the like are used as curing agents for epoxy resins. Among these curing agents, the epoxy resin using novolac type phenolic resin as the curing agent is superior in moldability, moisture resistance, nontoxic, and inexpensive as compared with those using other curing agents. It is preferably used as a sealing material.

(Problems to be Solved by the Invention) In recent years, in the fields of semiconductors and integrated circuits, higher integration of elements and larger pellets are progressing. Epoxy resins using novolac-type phenolic resins as hardeners Then, when it is molded and cured, it shrinks and stresses the semiconductor element,
It has the drawback of poor reliability. That is, if a molded product (sealed product) using such a resin is subjected to a hot and cold cycle test, the bonding wire opens, resin cracks and pellet cracks occur, and the function as an electronic / electrical component cannot be achieved. was there.

The present invention has been made in order to eliminate these drawbacks, low stress and excellent in crack resistance, stress is not applied to semiconductor elements, etc., high reliability with no wire open or crack occurrence. It is intended to provide a resin composition for sealing.

[Structure of the Invention] (Means for Solving Problems) As a result of intensive studies conducted by the present inventors to achieve the above-mentioned object, the introduction of silylated butadiene rubber results in shrinkage during molding and curing. It was found that a resin composition having a small value, a low stress and an excellent crack resistance can be obtained, and the present invention has been completed. That is, the present invention includes (A) an epoxy resin, (B) a novolac type phenol resin, (C) a silylated butadiene rubber represented by the following general formula, and (However, R is an alkyl group, m is a rubber polymerization degree, and n is 1
Represents an integer of 3 to 3) (D) an inorganic filler as an essential component, 0.1 to 5% by weight of the silylated butadiene rubber of (C) with respect to the entire resin composition, and the inorganic material of (D) A sealing resin composition containing 25 to 90% by weight of a filler. Then, the encapsulating resin composition in which the equivalent ratio [(a) / (b)] of the epoxy group (a) of the epoxy resin and the fephenolic hydroxyl group (b) of the novolac type phenol resin is within the range of 0.1 to 10 It is a thing.

As the epoxy resin (A) used in the present invention, as long as it is a compound having at least two epoxy groups in the molecule, there are no particular restrictions on the molecular structure, molecular weight, etc., and widely used resins for encapsulating materials are widely used. Can be included. Examples thereof include bisphenol type aromatic resins, alicyclic resins such as cyclohexane derivatives, and epoxy novolac resins represented by the following general formula.

(However, in the formula, R ¹ represents a hydrogen atom, a halogen atom or an alkyl group, R ² represents a hydrogen atom or an alkyl group, and n represents an integer of 1 or more). These epoxy resins can be used alone or
Use as a mixture of two or more species.

Examples of the (B) novolak type phenolic resin used in the present invention include novolak type phenolic resins obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof, for example, epoxidized or butylated novolaks. Examples include type phenol resins. These resins are used alone or in combination of two or more. The compounding ratio of the novolac type phenol resin is such that the equivalent ratio [(a) / (b)] of the epoxy group (a) of the (A) epoxy resin and the phenolic hydroxyl group (b) of the (B) novolac type phenol resin is It is desirable to be in the range of 0.1 to 10. If this equivalent ratio is less than 0.1 or exceeds 10, the moisture resistance, the molding workability and the electrical properties of the cured product deteriorate, which is not preferable in any case. Therefore, it is limited within the above range.

The (C) silylated butadiene rubber used in the present invention has the following general formula: (However, R is an alkyl group, m is a rubber polymerization degree, and n is 1
Which represents an integer of 3 to 3), and is not particularly limited to the molecular weight or the like. Specific compounds include, for example, And the like, and these are used alone or in admixture of two or more. The compounding ratio of the silylated butadiene rubber is preferably 0.1 to 5% by weight based on the total resin composition. If the proportion is less than 0.1% by weight, it is not effective for low stress and warm and cold cycles, and if it exceeds 5% by weight, hygroscopicity becomes high, which is not suitable for practical use, which is not preferable.

Examples of the (D) inorganic filler used in the present invention include silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, red iron oxide, glass fiber, carbon fiber and the like, which may be used alone or Two
Use as a mixture of two or more species. Of these, silica powder and alumina are preferably used. The blending ratio of the inorganic filler is preferably 25 to 90% by weight based on the total resin composition. If the proportion is less than 25% by weight, it has no effect on moisture resistance, heat resistance, mechanical properties and moldability, and 90% by weight.
If it exceeds, the dryness becomes large and the moldability is poor, which is not suitable for practical use.

The encapsulating resin composition of the present invention contains an epoxy resin, a novolac type phenolic resin, a silylated butadiene rubber and an inorganic filler as essential components, but unless necessary to impair the object of the present invention, for example, natural Waxes, synthetic waxes, metal salts of straight-chain fatty acids, acid amides, esters, paraffins and other mold release agents, chlorinated paraffins, bromotoluene, hexabromobenzene, flame retardants such as antimony trioxide, carbon black, A colorant such as red iron oxide, a silane coupling agent, various curing accelerators and the like can be appropriately added and blended.

A general method for producing the encapsulating resin composition of the present invention as a molding material is to use an epoxy resin, a novolac type phenol resin, a silylated butadiene rubber, an inorganic filler, and other raw material components selected in a predetermined composition ratio. After sufficiently uniform mixing with a mixer or the like, melt mixing treatment with a hot roll or mixing treatment with a kneader or the like is further performed, followed by cooling and solidification, and pulverization into an appropriate size to obtain a molding material. The molding material thus obtained can be applied to sealing, covering, insulating, etc. of electronic parts or electric parts.

(Function) In the encapsulating resin composition of the present invention, by adding a silylated butadiene rubber, it is possible to impart flexibility to the resin composition, relieve stress, and provide low stress.

(Examples) Next, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples. In the following Examples and Comparative Examples, "%" means "% by weight"
Means

Example 1 Cresol novolac epoxy resin (epoxy equivalent 21
5) 18%, novolac type phenol resin (phenol equivalent 107) 9%, silylated butadiene rubber 3% represented by the following formula, 69% of fused silica powder, 0.3% of hardening accelerator, 0.3% of ester wax and 0.4% of silane coupling agent were mixed at room temperature, further kneaded at 90 to 95 ° C, cooled, and then pulverized to obtain a molding material. . This molding material was transfer-injected into a mold heated to 170 ° C. and cured to form a molded product (sealed product). This molded product was tested for various properties related to moisture resistance, stress, etc., and the results are shown in Table 1.
The remarkable effect of the present invention was recognized.

Example 2 Cresol novolac epoxy resin (epoxy equivalent 21
5) 18%, novolac type phenolic resin (phenol equivalent 107) 9%, silylated butadiene rubber 3% represented by the following formula: Example 1 containing 69% silica powder, 0.3% curing accelerator, 0.3% ester wax and 0.4% silane coupling agent.
Mixing, kneading and crushing were carried out in the same manner as above to obtain a molding material. Also, a molded product was obtained in the same manner, and various properties related to moisture resistance, stress, etc. were tested on the molded product in the same manner as in Example 1, and the results are shown in Table 1. The remarkable effect of the present invention was recognized.

Comparative Example Cresol novolac epoxy resin (epoxy equivalent 21
5) 20%, novolac type phenol resin (phenol equivalent 107) 10%, silica powder 69%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent
0.4% was mixed, kneaded and pulverized in the same manner as in Example 1 to obtain a molding material. A molded product was formed using this molding material, and various characteristics of the molded product were tested in the same manner as in Example 1. The results are shown in Table 1.

[Effects of the Invention] As is clear from the above description and Table 1, the encapsulating resin composition of the present invention has low stress and excellent crack resistance, so that the opening of the bonding wire and the resin crack, No pellet cracks occur, and the stress due to shrinkage during curing is low. Therefore, by using this resin composition, highly reliable electronic and electric parts can be obtained.

Claims (2)

[Claims] 1. An epoxy resin (A), a novolac type phenolic resin (B), and a silylated butadiene rubber represented by the following general formula: (However, R is an alkyl group, m is a rubber polymerization degree, and n is 1
Represents an integer of 3) (D) Inorganic filler as an essential component, and the above (C) with respect to the entire resin composition.
0.1 to 5% by weight of the silylated butadiene rubber and 25 to 90% by weight of the inorganic filler (D), and a sealing resin composition. 2. The equivalent ratio [(a) / (b)] of the epoxy group (a) of the epoxy resin and the phenolic hydroxyl group (b) of the novolac type phenol resin is in the range of 0.1 to 10. The encapsulating resin composition according to claim 1.