JPH0739466B2 - Sealing resin composition and method for producing the same - Google Patents

Description

The present invention relates to a resin composition for encapsulating electronic or electric parts, which has low stress and excellent moisture resistance, and a method for producing the same.

(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 has been widely put into practical use because it is economically advantageous as compared with the hermetic sealing method using glass, metal, or ceramic. Among thermosetting resin compositions used for resin encapsulation, epoxy resin compositions are most commonly used. Curing agents such as acid anhydrides, aromatic amines and novolac type phenolic resins are used in the epoxy resin composition, but the epoxy resin composition using the novolac type phenolic resin as a curing agent may be replaced with other curing agents. It is widely used as a semiconductor encapsulating material because it is superior in moldability and moisture resistance, has no toxicity, and is cheaper than those used.

However, the epoxy resin composition using a novolac phenolic resin as a curing agent has a drawback that it shrinks during molding and curing and stress is applied to the semiconductor element, which deteriorates the reliability of the element. When a hot and cold cycle test of a molded product using such a resin composition is performed, there is a problem that the bonding wire opens, resin cracks, pellet cracks and the like occur, and the function as an electronic component cannot be achieved. Further, there is a method of adding a third component in order to reduce the stress of the resin composition, but in this method, the third component forms a secondary aggregate and cannot be uniformly dispersed in the resin composition, Therefore, there is a drawback that the low stress characteristics vary.

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned drawbacks, has no variations in low stress characteristics, is excellent in moisture resistance, and has characteristics of conventional epoxy resin compositions. It is intended to provide a highly reliable encapsulating resin composition that retains the above and a method for producing the same.

[Structure of the Invention] (Means for Solving Problems) As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that acrylonitrile-butadiene-styrene copolymer resin is uniformly dispersed in an epoxy resin. The present invention has been completed by finding that the dispersion of low stress characteristics can be eliminated by using a resin mixed and dispersed. That is, the present invention provides a resin [(A) + (B)] in which (B) an acrylonitrile / butadiene / styrene copolymer resin is uniformly dispersed and mixed in (A) an epoxy resin, (C) a novolac type phenol resin, and (D) A resin composition for encapsulation, which comprises an inorganic filler as an essential component. Also, (A) epoxy resin is melted, and (B) acrylonitrile.
A resin [(A) + (B)] in which a butadiene / styrene copolymer resin has been added and uniformly dispersed and mixed, and (C) a novolac type phenol resin are pulverized, and then (D) an inorganic filler and, if necessary, In addition, the present invention is a method for producing a resin composition for encapsulation, which comprises adding and mixing other components, further kneading with heating, and then cooling, solidifying and grinding.

The (A) epoxy resin used in the present invention is not particularly limited in terms of molecular structure, molecular weight, etc., as long as it is a compound having at least two epoxy groups in its molecule, and those used for general encapsulating materials can be used. Can be broadly 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 are one kind or a mixture of two or more kinds. To use.

The novolak type phenolic resin (C) used in the present invention is a novolak type phenolic resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof, for example, epoxidized or butylated novolac. Type phenolic resin. The mixing ratio of the novolac type phenol resin is the molar 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 preferably in the range of 0.1 to 10. If this molar 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 preferable to limit it to the above range.

(B) Acrylonitrile-butadiene-used in the present invention
The styrene copolymer resin includes a blend type of styrene / acrylonitrile copolymer and butadiene / acrylonitrile rubber, and a latex type of polybutadiene dissolved in a mixed monomer of styrene / acrylonitrile for suspension polymerization. Can be either
Generally commercially available products may be used. Acrylonitrile
The mixing ratio of the butadiene / styrene copolymer resin is 0.1 to 60% by weight based on the resin [(A) + (B)] in which the acrylonitrile / butadiene / styrene copolymer resin is uniformly dispersed and mixed in the epoxy resin. It is desirable to do. If the proportion is less than 0.1% by weight, there is no effect of withstanding low stress and warm and cold cycles, and if it exceeds 60% by weight,
It cannot be uniformly dispersed and mixed in the epoxy resin. The acrylonitrile / butadiene / styrene copolymer resin is melt-mixed by heating in an epoxy resin and uniformly dispersed and mixed. The method of uniform dispersion in the epoxy resin is to put the epoxy resin in a device (container) that can be heated to a temperature above the melting point of the epoxy resin, heat it above the melting point to form a completely molten liquid, and then add acrylonitrile A butadiene / styrene copolymer resin is added, and the mixture is stirred at preferably 150 ° C. or higher for 20 minutes or longer to uniformly disperse and mix. The resin [(A) + (B)] in which the acrylonitrile / butadiene / styrene copolymer resin is dispersed and mixed in the epoxy resin is preferably contained in a ratio of 1 to 50% by weight with respect to the entire resin composition. .
If the blending ratio is less than 1% by weight, it has no effect on lowering the stress,
On the other hand, if it exceeds 50% by weight, the acrylonitrile / butadiene / styrene copolymer resin is not uniformly dispersed and the viscosity increases, which is not preferable.

Examples of the inorganic filler (D) used in the present invention include silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, asbestos, mica,
Red iron oxide, glass fiber, carbon fiber and the like are mentioned, and these are used alone or in combination of two or more. Among these, silica powder and alumina are particularly preferable. The blending ratio of the inorganic filler is 25 to 90 with respect to the entire composition.
It is desirable that the content is wt%. 25% by weight
If it is less than 90%, there is no effect on the moisture resistance, heat resistance, mechanical properties and moldability, and if it exceeds 90% by weight, the bulkiness becomes large and the moldability becomes poor, which is not suitable for practical use.

The encapsulating resin composition of the present invention contains an epoxy resin, an acrylonitrile-butadiene-styrene copolymer resin, a novolac-type phenol resin and an inorganic filler as essential components, but if necessary, for example, natural waxes and synthetic waxes. , Linear fatty acid metal salts, acid amides, esters, paraffins and other mold release agents, chlorinated paraffin, bromtoluene, hexabromobenzene, flame retardants such as antimony trioxide, silane coupling agents, various curing accelerators It is also possible to appropriately add and blend agents and the like.

The method for producing the encapsulating resin composition of the present invention may be acrylonitrile / butadiene / styrene copolymer resin, which may be heat-mixed in an epoxy resin, and may be a resin uniformly dispersed and mixed, and is particularly limited to the production method. It will not be done. However, it is usually manufactured as follows. Using a device (container) that can heat to a temperature above the melting point of the epoxy resin, such as a universal mixer, a strong kneader, a heating reaction kettle, etc., charge the epoxy resin and heat it above the melting point to completely melt it. After that, 0.1 to 60% by weight of acrylonitrile-butadiene-styrene copolymer resin is added to the epoxy resin, and preferably stirred at 150 ° C or higher for 20 minutes or longer,
Disperse and mix evenly. Epoxy resin in which acrylonitrile / butadiene / styrene copolymer resin is uniformly dispersed and mixed, and novolac type phenol resin are pulverized, and then the raw material composition in which the inorganic filler and other components are selected in a predetermined composition ratio is blended. After sufficiently homogeneously mixing with each other, the mixture is further heated and kneaded by a hot roll, an extruder, a kneader or the like, cooled and solidified, and then crushed to an appropriate size to produce a sealing resin composition. The manufacturing method of dispersing and mixing the acrylonitrile / butadiene / styrene copolymer resin in the epoxy resin and then blending other components has been described above.However, in the manufacturing process of the epoxy resin, the acrylonitrile / butadiene / styrene copolymer resin is uniformly dispersed. It is also possible to prepare a mixed resin and mix and knead the necessary amount with other components as necessary.

(Function) By uniformly dispersing and mixing the acrylonitrile / butadiene / styrene copolymer resin in the epoxy resin, it is possible to reduce the production of secondary aggregates and eliminate the variation in low stress characteristics. The particle size of the acrylonitrile-butadiene-styrene copolymer resin is originally several μm or less, but when mixed and kneaded with other components, the particles of the acrylonitrile-butadiene-styrene copolymer resin aggregate and the particle size Secondary aggregates of 100 μm are generated, the low stress characteristics are deteriorated, and variations in the low stress characteristics occur, resulting in impaired reliability. Therefore, simply acrylonitrile-butadiene-styrene copolymer resin, epoxy resin,
If you do not mix and knead the novolac type phenolic resin and the inorganic filler, but disperse the acrylonitrile / butadiene / styrene copolymer resin in the epoxy resin sufficiently evenly, the secondary agglomerates will be less and less In addition, it was confirmed that the low stress characteristics are excellent and the variation is eliminated. The particle size of the acrylonitrile / butadiene / styrene copolymer resin can be arbitrarily adjusted depending on the mixing conditions (temperature, time, etc.), but it is preferable that the dispersed state is within the range of 0.1 to 50 μm.

The encapsulating resin composition of the present invention thus obtained can be applied to encapsulation, coating, insulation and the like of electronic or electric parts.

(Examples) 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".

Manufacture of resin Cresol novolac epoxy resin (epoxy equivalent 21
5) Put 85% into universal mixer and heat to 150 ℃. After the cresol novolac epoxy resin was completely melted, 15% of acrylonitrile-butadiene-styrene copolymer resin was added and mixed by heating and stirring for 1 hour to obtain a resin in which the acrylonitrile-butadiene-styrene copolymer resin was uniformly dispersed and mixed (hereinafter referred to as E -Called ANBS resin).

Example 1 20% of E-ANBS resin and 10% of novolak type phenolic resin (phenol equivalent 107) were crushed with a screen 2 mm of a Yariya crusher, and 65% of fused silica powder and 5% of other components were mixed at room temperature, and further 90%. After kneading and cooling at -100 ° C, it was pulverized to produce a sealing resin composition. 175 the resulting composition
Transfer molding was injected into a mold heated to ℃ and cured to obtain a molded product (sealed product). For this molded product, moisture resistance, strain, particle size of ABS resin, and other tests were performed.
The results are shown in Table 1. The encapsulating resin composition of the present invention has a well-dispersed ABS resin, a hot and cold cycle, moisture resistance,
It was excellent in low stress characteristics, and the remarkable effect of the present invention was recognized.

Example 2 E-ANBS resin 18% and novolac-type phenol resin (phenol equivalent 107) 1% were crushed with a screen 2 mm of a yaiya crusher, and mixed with fused silica powder 65% and other components 5%, and as in Example 1. Similarly, a sealing resin composition and a molded product were prepared. Further, various properties were similarly tested, and the results are shown in Table 1. Similar to Example 1, the remarkable effect of the present invention was confirmed.

Comparative Example 1 Cresol novolac epoxy resin (epoxy equivalent 21
5) 18% of novolac type phenolic resin (phenol equivalent 107) 9%, ABS resin 3%, fused silica powder 65% and other components 5% are mixed at room temperature, further kneaded and cooled at 90 to 100 ° C, and then pulverized. Then, a resin composition for sealing was manufactured. Then, a molded product was obtained using this composition, and various properties were tested in the same manner as in Examples. The results are shown in Table 1.

Comparative Example 2 Cresol novolac epoxy resin (epoxy equivalent 21
5) 20% to 10% novolac type phenolic resin (phenol equivalent 107), fused silica powder 65% and other components 5%
Was obtained in the same manner as in Comparative Example 1, and various properties were tested in the same manner as in Comparative Example 1, and the results are shown in Table 1.

[Effects of the Invention] As is clear from the above description and Table 1, according to the encapsulating resin composition and the method for producing the same of the present invention, the acrylonitrile / butadiene / styrene copolymer resin is heated and mixed in the epoxy resin. By evenly dispersing and mixing,
The secondary agglomerates were small, the low stress characteristics were excellent, there was no variation, the humidity resistance was excellent, and the characteristics equivalent to those of conventional epoxy resin compositions were obtained. Excellent reliability can be imparted to an electronic part or an electric part using this composition.

Front Page Continuation (72) Inventor Masanori Kokubo 5-14-25 Ryoke, Kawaguchi City, Saitama Prefecture Kawaguchi Plant, Toshiba Chemical Co., Ltd. (72) Inventor Akira Zensaku 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Prefecture 1 Stock Association (56) Reference JP-A-61-233051 (JP, A) JP-A-60-8315 (JP, A) JP-A-60-1220 (JP, A) JP-A-62-141018 ( JP, A)

Claims (6)

[Claims] 1. A resin [(A) + (B)] in which (B) an acrylonitrile / butadiene / styrene copolymer resin is uniformly dispersed and mixed in (A) an epoxy resin, (C) a novolac type phenol resin, and ( D) A resin composition for sealing, which comprises an inorganic filler as an essential component. 2. Acrylonitrile / butadiene / styrene copolymer resin is used in an amount of 0.1 to 6 relative to the resin [(A) + (B)].
The encapsulating resin composition according to claim 1, wherein the encapsulating resin composition is contained in a proportion of 0% by weight. 3. The encapsulation according to claim 1 or 2, wherein the resin [(A) + (B)] is contained in a proportion of 1 to 50% by weight with respect to the entire resin composition. Resin composition. 4. The encapsulating resin composition according to any one of claims 1 to 3, wherein the inorganic filler is contained in a proportion of 25 to 90% by weight with respect to the entire resin composition. 5. A molar 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 any one of claims 1 to 4. 6. A resin obtained by melting an epoxy resin (A), adding (B) an acrylonitrile / butadiene / styrene copolymer resin therein, and uniformly dispersing and mixing the resin [(A) +
(B)] and (C) novolac type phenolic resin are pulverized, then (D) inorganic filler and other components as required are added and mixed, and further heat kneaded, followed by cooling, solidifying and pulverizing. A method for producing a resin composition for sealing, which is characterized.