KR910008562B1 - Epoxy resin compositions for encapsulating semi - conductor elements - Google Patents

Abstract

An epoxy resin compsn. comprises 10-30 wt.pts. of cresol novolak epoxy resin (1), 5-20 wt.pts. of phenol novolak resin (2), 2-20 wt.pts. of silicon-modified epoxy resin (3), 60-80 wt.pts. of inorganic filler (4) and 0.2-5 wt.pts. of copolymer (5) of silicon and n-butyl acrylate. The resin (1) is pref. 180-240 epoxy equivalent and 60-110 deg.C softening point, and the resin (3) is prepd. by reacting a reactive silicon cpd. with a cresol novolak epoxy resin. The resin compsn. for sealing a semiconductor device has a low internal stress and a good heat-resistance and moldability.

Description

Epoxy Resin Compositions for Semiconductor Device Encapsulation

The present invention relates to an epoxy resin composition used to encapsulate a semiconductor device, and more particularly, to an epoxy resin composition for sealing a semiconductor resin having a low internal stress and having excellent heat resistance and moldability. It is about.

In recent years, high integration of semiconductor devices has progressed, and as a result, high functions and enlargement of devices have progressed, and aluminum wiring tends to become finer. Epoxy resin compositions used for encapsulation of semiconductor devices have good heat resistance, moisture resistance, and mechanical strength, but there is a significant difference in coefficient of thermal expansion between semiconductor devices and epoxy resins. When a change is made, internal stress is generated largely, so that the surface of the device is cracked, cracks in the inside, cutting of the bonding wire, cracking of the passivation layer, deformation or slipping of the aluminum wiring, etc. Problem occurs. Therefore, a semiconductor element molded from an encapsulant having a large internal stress causes a decrease in reliability.

As a method for lowering the internal stress of the cured product proposed as a problem, a method of lowering the glass transition temperature of the encapsulating resin, a method of reducing the difference between the coefficient of thermal expansion of the encapsulating resin and the thermal expansion coefficient of the encapsulating resin, and reducing the elastic modulus of the encapsulating resin There is a way.

Lowering the glass transition temperature of the above method has the disadvantage of deteriorating the high temperature characteristics of the resin composition, and in the case of weighing an inorganic filler having a low coefficient of thermal expansion, in order to reduce the coefficient of thermal expansion coefficient, conversely, the elastic modulus becomes high and the moldability deteriorates. There is this.

In addition, a method of lowering the elastic modulus of the encapsulating resin is to use bisepoxy having a long side branch such as polypropylene glycol diglycidyl ether, or to use a reactive liquid rubber such as low molecular weight polybutadiene having carboxyl or amino terminal groups. There are ways to use. However, when such additives are used until the elastic modulus is sufficiently low, the mechanical strength is lowered and the high temperature characteristics are deteriorated.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said problem, the present inventors completed the present invention by obtaining an epoxy resin composition for semiconductor element encapsulation excellent in heat resistance and moldability, which has a low flexural modulus and does not lower mechanical strength. Was done.

That is, the present invention

(1) 10-30 parts by weight of a cresol noblock epoxy resin

(2) 5-20 weight part of phenol noble resin

(3) 2-20 parts by weight of a silicone-modified epoxy resin

(4) 60-80 parts by weight of inorganic filler

(5) It is related with the copolymer of silicone and n-butyl acrylate, and 0.2-5 weight part, It is related with the epoxy resin composition for semiconductor element sealing characterized by the above-mentioned.

Hereinafter, the present invention will be described in detail.

The cresol noblock epoxy resin of (1) component used by this invention is an epoxy resin whose epoxy equivalent is 180-240 and a softening point of 60-110 degreeC, and contains 3 or more epoxy groups in 1 molecule. Moreover, in order to provide flame retardance to the cresol noblock epoxy resin of the said (1) component, it is preferable to contain 10-30% brominated epoxy resin normally in all the epoxy resins.

The use amount of the said epoxy resin is 10 weight part suitably, when the usage-amount is 10 weight part or less, moisture resistance falls, and when it is 30 weight part or more, mechanical strength will worsen.

The phenol noblock resin of (2) component used for this invention must contain 2 or more hydroxyl groups in 1 molecule as a hardening | curing agent of the epoxy resin which has (1) component as a main component.

At this time, the amount is preferably 5 to 20 parts by weight.

If the amount of use is 5 parts by weight or less, the crosslinking density is low, and the mechanical strength is poor.

The silicone-modified epoxy resin of component (3) used in the present invention is obtained by reacting a reactive silicone compound with an epoxy resin of component (1). The silicon used herein has a repeating unit structure of [Si-O]. As a structure formed, dimethyl silicone, methylphenyl silicone, alkyl modified silicone, fatty acid modified silicone, epoxy modified silicone, dimethyl diphenyl copolymer silicone, etc. are mentioned, for example. The amount of the silicone-modified epoxy compound may be 2 to 20 parts by weight. If the amount is 2 parts by weight or less, the modulus of elasticity is low, and the effect is insignificant.

Inorganic fillers of component (4) used in the present invention include silicon oxide, calcium carbonate, alumina, molten silica, crystalline silica, glass, magnesite, gypsum, graphite, cement, iron carbonyl, tar, mica, silica sand, kaolin , Aluminum hydroxide, asbestos, and the like, which may be used alone or in combination of two or more thereof. The blending ratio of the inorganic filler is used 60-80 parts by weight of the total composition is less than 60 parts by weight, the coefficient of thermal expansion is increased to generate cracks, when using more than 80 parts by weight fluidity is lowered.

The copolymer of silicone of component (5) and n-butyl acrylate used in the present invention is obtained by reacting n-butyl acrylate with a reactive silicone compound. The reactive silicone compound to be used should have at least two reactors capable of reacting with at least a carboxyl group in one molecule, and examples thereof include an epoxy group, a hydroxyl group, an amine group, and a carboxyl group.

The weight ratio of n-butyl acrylate to silicon in the polymerization reaction is suitably 30-50. When the weight ratio exceeds 50, it is difficult to control the reaction due to excessive heat of reaction.

The epoxy resin composition for semiconductor element encapsulation of the present invention is an organic phosphine compound such as triphenyl phosphine, tributyl phosphine, dimethyl phosphine, etc. for the purpose of making the above components an essential component and promoting the curing speed during molding. 0.1-5 weight part can be used. When the blending ratio of such a curing accelerator is less than 0.1 parts by weight, the curing rate is slow, and when 5 parts by weight or more, moisture resistance may deteriorate.

In the composition of the present invention, known additives such as release agents such as natural waxes, higher fatty acids and metal salts thereof, coupling agents of epoxy silanes, colorants such as carbon black, and flame retardant aids such as antimony trioxide may be 10 parts by weight or less. It is preferable to mix and use.

Referring to the production method of the epoxy resin composition of the present invention in detail.

(5) The component is melted and mixed with the epoxy resin of the component (1) for 30 minutes at 140 ° C to 160 ° C, and then cooled to obtain a solid compound. The mixture is pulverized small with other compositions, mixed uniformly using a mixer such as Henschel mixer, melted and kneaded with a heating roller, kneader, heating extruder, etc. Can be used.

Hereinafter, the present invention will be described in detail with reference to Examples.

The cresol noblock resin epoxy resin used in each Example and the comparative example is epoxy equivalent 213, softening point 79 degreeC, and the softening point of the brominated phenyl noblock resin is 110 degreeC. Parts used in Preparation Examples, Comparative Examples and Comparative Examples are all based on parts by weight.

[Production Example 1]

60 parts of reactive silicone was placed in a reactor and the temperature was raised to 100 ° C, followed by 27 parts of n-butyl acrylate, 1.5 parts of acrylic acid, and 3 parts of 4,4'-azobis- (4-cyano valeric acid) and di 0.2 part of cumyl peroxide is added and polymerization is carried out with sufficient stirring. The product produced here is called SBA-I.

Example 1

After mixing with the ingredients and amounts shown in Table 1, and then heated and kneaded at 75-85 ° C between two rolls to be pulverized to a certain particle size for convenient use to obtain a resin composition for semiconductor encapsulation of the present invention . The spiral properties of the composition obtained as described above were measured, and a specimen for evaluation of physical properties was prepared using a low pressure transfer molding machine, and cured after 8 hours at 175 ° C. The spiral flow was measured according to EMMI-166 (Epoxy Molding Material Institute; Society of Plastic Industry) using a spiral mold, and the flexural modulus was measured according to ASTM D-790. , Coefficient of thermal expansion and glass transition temperature were measured using TMA (Thermo mechanical Anaylsis) method.

Comparative Example 1

The composition of the present invention was prepared by mixing the same ingredients and amounts shown in Table 1 in the same manner as in Example 1, except that 16.1 parts by weight of a cresol noblock epoxy resin was used instead of the SBA-1 and silicone-modified epoxy resin used in Example 1. And the test in the same manner as in Example and the results are shown in Table 1.

Comparative Example 2

Except for using the cresol novolac epoxy resin 8.1 parts by weight, and the silicone-modified epoxy resin 8 parts by weight in place of the cresol noblock epoxy resin in Comparative Example 1 in the same manner as in Example 1 in the components and amounts shown in Table 1 The composition was prepared and tested in the same manner as in Example 1, and the results are shown in Table 1.

TABLE 1

As can be seen from Table 1, in the present invention, when SBA-1 and SBA-2 are used instead of the conventional cresol noblock epoxy resin, the flexural modulus decreases and the flexural strength does not decrease, indicating that the composition has excellent heat resistance and moldability. have.

Claims (6)

(1) 10-30 parts by weight of cresol noblock epoxy resin (2) 5-20 weight part of phenol noble resin (3) 2-20 parts by weight of a silicone-modified epoxy resin (4) 60-80 parts by weight of inorganic filler (5) An epoxy resin composition for semiconductor element encapsulation, comprising a copolymer of silicon and n-butyl acrylate and 0.2-5 parts by weight. The epoxy resin composition for semiconductor element encapsulation according to claim 1, wherein the cresol noblock epoxy resin has an epoxy equivalent of 180 to 240 and a softening point of 60 to 110 ° C. The epoxy resin composition for semiconductor element encapsulation according to claim 1 or 2, wherein the cresol noblock epoxy resin contains three or more epoxy groups in one molecule. The epoxy resin composition for semiconductor element encapsulation according to claim 1, wherein the silicone-modified epoxy resin is prepared by reacting a reactive silicone compound with a cresol noblock epoxy resin. The epoxy resin composition for semiconductor element encapsulation according to claim 4, wherein the reactive silicone compound is dimethylsilicone, methylphenylsilicone, alkyl modified silicone, fatty acid modified silicone, epoxy modified silicone, dimethyl diphenyl copolymerized silicone. The inorganic filler according to claim 1, wherein the inorganic filler is silicon oxide, calcium carbonate, alumina, molten silica, crystalline silica, glass, masnecite, gypsum, graphite, cement, iron carbonyl, tar, mica, silica sand, kaolin, aluminum hydroxide, Epoxy resin composition for sealing semiconductor elements, characterized in that selected from asbestos.