JPH068339B2 - 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, an epoxy resin composition using a novolac type phenol resin as a curing agent has a drawback that it shrinks during molding and curing and stress is applied to a semiconductor element, which deteriorates reliability of the element. When a cold cycle test of a molded product using such a resin composition is performed, opening of a bonding wire, resin crack, pellet crack, etc. occur,
There was a problem that the function as an electronic component could not be fulfilled. Further, there is a method of adding a third component in order to reduce the stress of the resin composition, but the third component forms a secondary aggregate and cannot be uniformly dispersed in the resin composition, which results in a low stress. There is a drawback that the 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 methylmethacrylate / butadiene / styrene copolymer resin in novolac type phenol resin The present invention has been completed by finding that variations in low stress characteristics can be eliminated by using a resin that is uniformly dispersed and mixed. That is, the present invention relates to a resin ((A) + (B)) and (C) epoxy resin in which (B) methyl methacrylate / butadiene / styrene copolymer resin is uniformly dispersed and mixed in (A) novolac type phenol resin. And (D) an inorganic filler as an essential component, which is a sealing resin composition. Also, (A)
Novolak type phenolic resin is melted and (B)
Resin ((A) +) in which methylmethacrylate / butadiene / styrene copolymer resin was added and uniformly dispersed and mixed.
(B)] and (C) epoxy resin are pulverized, then (D) inorganic filler and other optional components are added and mixed, and the mixture is further heated and kneaded, and then cooled, solidified and pulverized. Is a method for producing a sealing resin composition.

Examples of the (A) 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 such as epoxidized or butylated novolaks. Type phenolic resin. The mixing ratio of the novolac type phenol resin is 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 described below.
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.

The (C) 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 two or more kinds. Use by mixing.

The (B) methylmethacrylate / butadiene / styrene copolymer resin used in the present invention has a butadiene composition ratio of 70% by weight or less and a methylmethacrylate composition ratio of 70% by weight or less.
The content is preferably 15% by weight or more, and if the composition ratio is outside this range, the appearance of the molded product is impaired, which is not preferable. The methylmethacrylate / butadiene / styrene copolymer resin is blended in a novolak type phenol resin with a uniform dispersion of methylmethacrylate / butadiene / styrene copolymer resin [(A) + (B)] in an amount of 0.1 to 60% by weight. It is desirable to contain it in the ratio of%. 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, uniform dispersion and mixing cannot be carried out in the novolac type phenol resin. The methylmethacrylate / butadiene / styrene copolymer resin is heated and melt mixed in a novolac type phenol resin, and uniformly dispersed and mixed. The method of uniformly dispersing in the novolac type phenol resin is to put the novolac type phenol resin in a device (container) that can heat to a temperature above the melting point of the novolak type phenol resin, and heat it above the melting point to completely melt the liquid. After that, a methyl methacrylate / 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. Methyl methacrylate, butadiene,
Resin [(A) + in which styrene copolymer resin is mixed and dispersed
(B)] is preferably contained in a proportion of 1 to 30% by weight based on the entire resin composition. If the blending ratio is less than 1% by weight, it is not effective for low stress, and if it exceeds 30% by weight, the dispersion of the methyl methacrylate / butadiene / styrene copolymer resin becomes non-uniform and the viscosity is increased, 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 a novolac type phenol resin, a methylmethacrylate / butadiene / styrene copolymer resin, an epoxy resin and an inorganic filler as essential components, but if necessary, for example, natural waxes and synthetic waxes. , Metal salts of straight chain fatty acids, mold release agents such as acid amides, esters and paraffins, chlorinated paraffins, flame retardants such as bromotoluene, hexabromobenzene, antimony trioxide, silane coupling agents, various curing Accelerators and the like can be appropriately added and blended.

In the method for producing the encapsulating resin composition of the present invention, a methylmethacrylate / butadiene / styrene copolymer resin is heated and mixed in a novolac type phenol resin, and a resin uniformly dispersed and mixed may be used. The manufacturing method is not limited. However, it is usually manufactured as follows. Using a device (container) capable of heating to a temperature above the melting point of the novolac type phenolic resin, for example, a universal mixer, a strong kneader, a heating reaction kettle, etc., charge the novolac type phenolic resin into this, and heat to above the melting point After completely melting, 0.1 to 6 against novolac type phenolic resin
Add 0% by weight of methylmethacrylate / butadiene / styrene copolymer resin, preferably 2
Stir for 0 minutes or more to uniformly disperse and mix. A novolac-type phenol resin and an epoxy resin, in which methyl methacrylate / butadiene / styrene copolymer resin is uniformly dispersed and mixed, are crushed, and then a raw material composition in which an inorganic filler and other components are selected to have 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 methylmethacrylate / butadiene / styrene copolymer resin in the novolac type phenol resin and then compounding other components has been described above. In the manufacturing process of the novolac type phenol resin, methylmethacrylate / butadiene / styrene is used. It is also possible to prepare a resin in which the copolymer resin is uniformly dispersed and mixed, and if necessary, mix and knead the necessary amount of other components.

(Function) By uniformly dispersing and mixing the methyl methacrylate / butadiene / styrene copolymer resin in the novolac type phenol resin, it is possible to reduce the production of secondary aggregates and eliminate the variation in low stress characteristics. The particle size of methylmethacrylate / butadiene / styrene copolymer resin is originally several μm or less, but when mixed and kneaded with other components, the particles of methylmethacrylate / butadiene / styrene copolymer resin aggregate to form particles. Secondary agglomerates having a diameter of several hundreds of μm are generated, the low stress characteristics are deteriorated, and the low stress characteristics vary, resulting in deterioration of reliability. Therefore, rather than simply mixing and kneading methyl methacrylate / butadiene / styrene copolymer resin, novolac type phenol resin, epoxy resin, and inorganic filler, methyl methacrylate / butadiene / styrene copolymer resin is sufficiently homogeneous in the novolac type phenol resin. It was confirmed that the secondary agglomerates were small and small, the low stress characteristics were excellent, and the dispersion and the like were eliminated when dispersed and mixed in. The particle size of the methylmethacrylate / butadiene / styrene copolymer resin can be arbitrarily adjusted depending on the mixing conditions (temperature, time, etc.), but the dispersed state is preferably 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 Novolac type phenolic resin (phenol equivalent 1078) 80
% In a universal mixer and heated to 150 ° C. After the novolac type phenolic resin is completely melted, 20% of methylmethacrylate / butadiene / styrene copolymer resin is added and mixed by heating and stirring for 1 hour to obtain a resin in which the methylmethacrylate / butadiene / styrene copolymer resin is uniformly dispersed and mixed ( Hereinafter referred to as P-MBS resin).

Example 1 P-MBS resin 12% and cresol novolac epoxy resin (epoxy equivalent 215) 18% were crushed with a 2 mm screen of a Yarya crusher, and fused silica powder 65% and other components 5% were mixed at room temperature, and further 90%. After kneading and cooling at -100 ° C, it was pulverized to produce a sealing resin composition. The obtained composition was transfer-injected into a mold heated to 175 ° C. and cured to obtain a molded product (sealed product). Moisture resistance, strain, particle size of MBS resin, and other tests were performed on this molded product, and the results are shown in Table 1. The MBS resin was well dispersed in the encapsulating resin composition of the present invention, and the encapsulating resin composition was excellent in hot and cold cycles, moisture resistance, and low stress characteristics, and the remarkable effects of the present invention were recognized.

Example 2 P-MBS resin 10% and cresol novolac epoxy resin (epoxy equivalent 215) 20% were crushed with a screen 2 mm of a Yarya crusher, and fused silica powder 65% and other components 5
%, And a sealing resin composition and a molded product were prepared in the same manner as in Example 1. 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) 18.5% of novolac type phenol resin (phenol equivalent 107) 9%, MBS resin 2.5%, fused silica powder 65% and other components 5% are mixed at room temperature, further kneaded and cooled at 90 to 10 ° 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, the methyl methacrylate / butadiene / styrene copolymer resin is used in the novolac type phenol resin. By heat-mixing and uniformly dispersing and mixing, secondary agglomerates are also small, excellent in low stress characteristics, no variation, excellent in moisture resistance, and those having characteristics equivalent to conventional epoxy resin compositions can be obtained. It was

Excellent reliability can be imparted to an electronic part or an electric part using this composition.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location H01L 23/31 (72) Inventor Masayuki Kawauchiyama 5-14-25 Ryoke, Kawaguchi City, Saitama Toshiba Chemical Kawaguchi Plant Co., Ltd. (72) Inventor Akira Zensaku 1 Komukai Toshiba-cho, Kouki-ku, Kawasaki-shi, Kanagawa Stock Research Institute, Toshiba Research Institute (56) Reference JP-A-55-125166 (JP, A) JP-B 47 -45193 (JP, B1)

Claims (6)

[Claims] 1. In (A) novolak type phenolic resin,
(B) Resin in which methyl methacrylate / butadiene / styrene copolymer resin is uniformly dispersed and mixed [(A) +
(B)], (C) epoxy resin, and (D) inorganic filler as an essential component, The sealing resin composition characterized by the above-mentioned. 2. A methylmethacrylate / butadiene / styrene copolymer resin is used with respect to the resin [(A) + (B)].
The encapsulating resin composition according to claim 1, wherein the encapsulating resin composition is contained in a proportion of 1 to 60% by weight. 3. The encapsulation according to claim 1 or 2, wherein the resin [(A) + (B)] is contained in a proportion of 1 to 30% 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 items 1 to 4. 6. A resin [(A) + (B)] in which (A) a novolac type phenolic resin is melted, and (B) a methyl methacrylate / butadiene / styrene copolymer resin is added therein and uniformly dispersed and mixed. And (C) an epoxy resin are pulverized, then (D) an inorganic filler and other optional components are added and mixed, and the mixture is further heated and kneaded, and then cooled, solidified and pulverized. A method for producing a resin composition.