JPH0621152B2 - 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 encapsulating an electronic / electrical component, which has low stress and excellent moisture resistance and the like.

(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. As a sealing resin composition, an epoxy resin composition is most commonly used among thermosetting resin compositions. Curing agents such as acid anhydrides, aromatic amines and novolac type phenolic resins are used in the epoxy resin composition. Among these, the epoxy resin composition using a novolac type phenolic resin as a curing agent is superior in moldability and moisture resistance, nontoxic, and inexpensive as compared with those using other curing agents, and thus semiconductor encapsulation. Widely used as a material.

(Problems to be Solved by the Invention) However, an epoxy resin composition using a novolac-type phenol resin as a curing agent has a drawback that the semiconductor element shrinks during molding and curing and stress is applied to the semiconductor element, resulting in poor reliability. 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 and pellet cracks occur, and the function as an electronic component cannot be achieved. Further, when molding is performed using this encapsulating resin composition, burrs are likely to be generated, and the number of steps for removing the burrs is increased in production, resulting in high cost. Further, a third component is added in order to reduce the stress of the resin composition, but this has a drawback that the mold is significantly contaminated.

The present invention has been made to solve the above-mentioned drawbacks, and provides a highly reliable encapsulating resin composition having low stress, excellent moisture resistance, and the advantages of conventional epoxy resin compositions. Is intended.

[Structure of Invention] (Means and Actions for Solving Problems) As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that when polynorbornene rubber is blended, low stress and moisture resistance are obtained. The present invention has been completed and the present invention has been completed.

That is, the present invention relates to (A) epoxy resin (B) novolac type phenol resin (C) polynorbornene rubber And (D) an inorganic filler as an essential component, the polynorbornene rubber (C) is contained in an amount of 0.1 to 30% by weight, and the inorganic filler (D) is added in an amount of 25 to 90% by weight based on the resin composition. It is a resin composition for sealing characterized by containing each.

As the epoxy resin (A) used in the present invention, as long as it is a compound having at least two epoxy groups in its molecule, there are no particular restrictions on the molecular structure, molecular weight, etc. 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.

(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 may be used alone or in combination of two or more. Used.

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. Type phenolic resin and the like. The mixing ratio of the novolac type phenol resin is such that the molar 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 molar ratio is less than 0.1 or exceeds 10,
Moisture resistance, molding workability, and electrical properties of the cured product deteriorate, which is not preferable in any case. Therefore, it is limited within the above range.

The (C) polynorbornene rubber used in the present invention is obtained by ring-opening polymerization of a norbornene monomer synthesized from ethylene and cyclopentadiene by a Diels-Alder reaction, and has the following structural formula.

The compounding ratio of the polynorbornene rubber is preferably in the range of 0.1 to 30% by weight based on the resin composition. If the proportion is less than 0.1% by weight, it is not effective for low stress and cold and warm cycles, and if it exceeds 30% by weight, it adversely affects moldability such as mold stains and increase in viscosity and is not suitable for practical use, which is not preferable. . It is speculated that the compounding of polynorbornene rubber imparts flexibility to the resin composition, relieves stress, and results in low stress. Further, unlike other rubbers, it has a small water absorption, and therefore exhibits an excellent effect on moisture resistance.

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 can be mentioned, and silica powder and alumina are particularly preferable. The blending ratio of the inorganic filler needs to be 25 to 90% by weight of the resin composition. If its content 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 bulkiness becomes large and the moldability is poor and it is not suitable for practical use.

The encapsulating resin composition of the present invention contains an epoxy resin, a novolac type phenolic resin, a polynorbornene rubber, and an inorganic filler as essential components, but if necessary, for example, natural waxes, synthetic waxes, linear fatty acid Mold release agents such as metal salts, acid amides, esters, paraffins, chlorinated paraffin, bromtoluene, hexabromobenzene, flame retardants such as antimony trioxide, carbon black, colorants such as red iron oxide, silane coupling agents, 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 a raw material composition in which an epoxy resin, a novolac type phenolic resin, a polynorbornene rubber, an inorganic filler and others are selected in a predetermined composition ratio. After mixing the components sufficiently uniformly with a mixer or the like, further melt mixing treatment with a hot roll, or mixing treatment with a kneader or the like,
Then, it is cooled and solidified, and crushed to 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.

(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%, polynorbornene rubber 1%, fused silica powder 71%, curing accelerator 0.3%, ester wax 0.3
% And silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., cooled, and then pulverized to obtain a molding material. The obtained molding material was transfer-injected into a metal heated to 170 ° C. and cured to obtain a molded product. The molded product was tested for various properties related to moisture resistance, stress, etc., and the results are shown in Table 1. The remarkable effects of the present invention were recognized.

Example 2 Cresol novolac epoxy resin (epoxy equivalent 21
5) 17%, novolac type phenolic resin (phenol equivalent 107) 8%, polynorbornene rubber 3%, fused silica powder 71%, hardening accelerator 0.3%, ester wax 0.3
%, And 0.4% of the silane coupling agent were mixed, kneaded and pulverized in the same manner as in Example 1 to obtain a molding material. Then, molded articles were obtained in the same manner and Example 1 was performed on these molded articles
Various properties relating to moisture resistance, stress, etc. were tested in the same manner as in, 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) 19%, novolac type phenolic resin (phenol equivalent 107) 9%, silica powder 71%, curing accelerator 0.3%, ester wax 0.3%, and silane coupling agent 0.4% in the same manner as in the example. A molding material was obtained. A molded product was formed using this molding material, and various characteristics of the molded product were tested in the same manner as in the examples. The results are shown in Table 1.

As is clear from Table 1, the encapsulating resin composition of the present invention has low stress, excellent moisture resistance, and excellent hot and cold cycles.

[Effects of the Invention] The encapsulating resin composition of the present invention is low in stress and excellent in moisture resistance, so that there is no occurrence of opening of bonding wires, resin cracks, or pellet cracks, and a conventional epoxy resin composition. It is a composition that retains its advantages, and when it is used for sealing, coating, insulating, etc. of electronic / electrical parts, a product with sufficiently high reliability can be obtained.

Claims (2)

[Claims] 1. An epoxy resin (A), a novolac type phenolic resin (B), and a polynorbornene rubber (C). And (D) an inorganic filler as an essential component, 0.1 to 30% by weight of the polynorbornene rubber of (C) and 25 to 90% by weight of the (D) inorganic filler to the resin composition. A resin composition for encapsulation, each of which is contained. 2. An 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.