JPS6222822A - Sealing resin composition - Google Patents

Abstract

PURPOSE:A resin composition excellent in moisture resistance and thermal cycling resistance and useful for sealing electronic components, prepared by mixing an epoxy resin with a novolak phenolic resin, a polybutylene terephthalate resin and an inorganic filler. CONSTITUTION:A mixture formed by mixing an epoxy resin (A) having at lest two epoxy groups in the molecule with a novolak phenol-modified resin (B) obtained by reacting a phenol with (para)formaldehyde at a molar ratio of the epoxy groups of component A to the phenolic hydroxyl groups of component B of 0.1-10 is mixed with 0.1-10wt% polybutylene terephthalate (C) obtained from polybutylene glycol and terephthalic acid, 25-90wt% inorganic filler (D) (e.g., silica powder) and, optionally, a mold release, a flame retardant, a colorant, a silane coupling agent, a cure accelerator, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a resin composition for sealing electronic components and the like with low stress and excellent moisture resistance and temperature/cold cycle resistance.

[Technical Background of the Invention and Problems thereof] In recent years, methods have been used to seal electronic components such as diodes, transistors, and integrated circuits using thermosetting resins. This resin sealing method is economically advantageous compared to the Hermedic sealing method using glass, metal, or ceramic, and is therefore widely put into practical use. Thermosetting resins are used as the sealing resin, and among them, epoxy resin is most commonly used. By the way, acid anhydrides, aromatic amines, novolak type phenolic resins, and the like are used as curing agents for epoxy resins.

Among these, epoxy resins that use novolak type phenolic resin as a curing agent are preferred as semiconductor encapsulation materials because they have excellent moldability and moisture resistance, are non-toxic, and are inexpensive compared to those that use other curing agents. It is widely used as

However, epoxy resins using novolac-type phenolic resin as a curing agent have the disadvantage that they shrink during molding and curing, applying stress to semiconductor elements, resulting in poor reliability. In other words, when a wet air cycle test is performed on molded products using such resins, bonding wire ovens,
Resin crank, Padgebegecon crack, Belen] ~
There was a problem in that cracks and the like occurred, making it impossible to function as an electronic component. These problems have become even more serious as semiconductor devices have recently become more highly integrated and larger. For these reasons, it has been desired to develop a sealing resin that maintains the advantages of conventional epoxy resins and has low stress.

[Object of the Invention] The object of the present invention was to solve the above-mentioned drawbacks and problems, and to provide a resin composition for sealing that has excellent moisture resistance, resistance to hot and cold cycles, low stress, and high reliability. This is what we are trying to provide.

[Summary of the Invention] As a result of intensive research to achieve the above object, the present inventors found that, as described below, by including polybutylene terephthalate resin, the immersion resistance is lower than that of conventional sealing resins. The inventors have discovered that it is possible to obtain a sealing resin composition that exhibits heat resistance, thermal cycleability, and low stress, and has led to the present invention.

That is, the present invention includes (Δ) an epoxy resin, (B) a novolac type phenol resin, (C) a polybutylene terephthalate resin, and (D) an inorganic filler, and the resin composition includes (C) a polybutylene terephthalate resin. 0.1 to 10% by weight of resin and (D)
This is a sealing resin composition characterized by containing 25 to 90% by weight of an inorganic filler. And the molar ratio of the epoxy group (a) of (A) epoxy resin to the phenolic hydroxyl group (b) of (B) novolak type phenolic resin [(a
)/(b)] is within the range of 0.1 to 10.

The epoxy resin (A) used in the present invention is not particularly limited in molecular structure, molecular weight, etc., as long as it is a compound having at least two epoxy groups in its molecule. Can be broadly encompassed.

Examples include aromatic resins such as bisphenol, alicyclic resins such as cyclohexane derivatives, and epoxy novolac resins represented by the following general formula. These epoxy resins may be used alone or in combination of two or more.

(In the formula, R1 represents a hydrogen atom, a halogen atom, or an argyl group, R2 represents a hydrogen atom or an alkyl group, and n represents an integer of 1 or more.) As the novolac type phenol resin (B) used in the present invention, Examples include novolac type phenol resins obtained by reacting phenols such as phenol and alkylphenols with formaldehyde or paraformaldehyde, and modified resins thereof such as epoxidized or butylated novolac type phenol resins. [
(a)/(b)] is 0.1 to 10 (7), IQ [I
[+] is preferable. If the molar ratio is less than 0.1 or more than 10, the moisture resistance, molding workability, and electrical properties of the cured product will deteriorate, and either case is unfavorable. Therefore, it is preferable to limit it within the above range.

The polybutylene terephthalate resin (C) used in the present invention is a resin consisting of polybutylene glycol and terephthalic acid. The blending ratio of polybutylene terephthalate resin is preferably 0.1 to 10% by weight based on the resin composition. If the blending ratio is less than 0.1% by weight, there is no effect of resisting low stress and hot/cold cycles, and if it exceeds 10% by weight, water absorption and moldability deteriorate, making it unsuitable for practical use.

Polybutylene terephthalate resin has good compatibility with epoxy resins and phenol resins, and is thought to impart flexibility to the resin composition and relieve stress, resulting in low stress.

Examples of the inorganic filler (D) used in the present invention include silica powder, alumina, antimony trioxide, talc, lucium carbonate, titanium white, clay, asbestos, mica, red iron, glass fiber, carbon fiber, etc. Silica powder and alumina are preferred. The blending ratio of the inorganic filler is preferably 25 to 90% by weight of the resin composition. If the amount is less than 25% by weight, there will be no effect on moisture resistance, heat resistance, mechanical properties and moldability;
If it exceeds 0% by weight, bulk will increase and moldability will be poor, making it unsuitable for practical use.

The sealing resin composition of the present invention contains an epoxy resin, a novolac type phenol resin, a polybutylene terephthalate resin, and an inorganic filler as essential components, but may optionally include natural waxes, synthetic waxes, straight chain fatty acids, etc. metal salts, acid amides, esters, mold release agents such as paraffins, chlorinated paraffins, flame retardants such as bromotoluene, hexabromobenzene, antimony trioxide, and carbon black.

Coloring agents such as red iron oxide, silane coupling agents, various curing accelerators, etc. can also be added and blended as appropriate.

Typical methods for producing the sealing resin composition of the present invention as a molding material include epoxy resin, novolac type phenol resin, polybutylene terephthalate resin,
After mixing the raw material composition containing the inorganic filler and others at a predetermined composition ratio sufficiently using a mixer, etc., it is further melted and mixed using hot rolls, or mixed using a kneader, etc., and then cooled and solidified. It can be pulverized to a suitable size and used as a molding material.

The molding material made of the encapsulating resin composition according to the present invention can be applied to encapsulating, covering, insulating, etc. electronic or electrical components.

[Effects of the Invention] The encapsulating resin composition of the present invention has excellent moisture resistance and moisture-air cycle, has low stress, and has good molding workability, and is suitable for encapsulating and coating electronic and electrical components. When used for insulation, etc., a product with sufficiently high reliability can be obtained.

[Examples of the Invention] The present invention will be specifically explained with reference to Examples, but the present invention is not limited to the following Examples.

In the Examples and Comparative Examples below, "%" means "% by weight".

Example 1 Talesol novolak epoxy resin (epoxy F17
215) 18%, 9% novolac type phenol resin (phenol equivalent fil 107), 2% polybutylene terephthalate resin, and 70% fused silica powder were mixed at room temperature, and then kneaded at 90 to 95°C and cooled. , and crushed to obtain a molding material. 1 of the obtained molding material
A molded product was obtained by transfer injection into a mold heated to 70° C. and curing. This molded article was tested for moisture resistance, stress and other properties, and the results are shown in Table 1.

Example 2 Cresol novolak epoxy resin (epoxy
215) 16%, novolak type phenolic resin (
A molding material was obtained by mixing, kneading, and pulverizing 8% of phenol, 4% of polybutylene terephthalate resin, and 70% of fused silica powder in the same manner as in Example 1.
Molded articles were then obtained in the same manner, and these molded articles were tested for moisture resistance, stress, and other properties in the same manner as in Example 1. The results are shown in Table 1.

Comparative example Cresol novolac epoxy resin (epoxy equivalent: 21
5) A molding material was obtained in the same manner as in the example from raw materials consisting of 20%, 10% novolac type phenol resin (phenol 107), and 70% silica powder. This molding material was used to make a molded article, and the properties of the molded article were tested in the same manner as in the Examples, and the results are shown in Table 1.

Table 1 *1: The number of cracks is determined by embedding a 25x25x3mm copper plate in the bottom of a 30x25x51111n molded product.
Place in constant temperature baths at 40℃ and +200℃ for 30 minutes each15
Resin cracks after repeated cycles were investigated.

*2: Using the sealing resin composition (molding material), an electrical component having two aluminum wirings was transfer-molded at 110°C for 3 minutes, and then cured at 180°C for 8 hours. For 100 sealed electrical components thus obtained, 1
A humidity test was conducted in high-pressure steam at 20° C., and the time required for 50% wire breakage (defect occurrence) due to aluminum corrosion was evaluated.

*3: A commercially available strain gauge was adhered to the island part of the DIP16 bin lead frame, and then cured at 180°C for 8 hours to further stabilize the strain.

As is clear from Table 1, the resin composition for 19 stop of the present invention is excellent in moisture resistance, humidity and air cycle, and has low stress.

Claims (1)

[Scope of Claims] 1. The resin composition contains (A) an epoxy resin, (B) a novolac type phenol resin, (C) a polybutylene terephthalate resin, and (D) an inorganic filler; 0.1 to 10% by weight of terephthalate resin and (D)
A sealing resin composition containing 25 to 90% by weight of an inorganic filler. 2 (A) Epoxy group (a) of epoxy resin and (B) phenolic hydroxyl group (b) of novolac type phenol resin
2. The sealing resin composition according to claim 1, wherein the molar ratio [(a)/(b)] is in the range of 0.1 to 10.