JPH05230187A - Epoxy resin composition for sealing - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent water vapor resistance, solder crack resistance and reliability of water vapor resistance, comprising an epoxy resin, a specific amount of a curing agent of cresol, a phosphorus- based curing promotor and an inorganic filler. CONSTITUTION:The objective composition comprising (A) an epoxy resin (e.g. biphenyl novolak type epoxy resin), (B) a curing agent of a cresol compound of formula I having a naphthalene skeleton containing a phenolic OH group in a functional group, (C) a phosphorus-based curing promotor (e.g. triphenylphosphine) and (D) an inorganic filler (e.g. fused silica). An epoxy compound of formula II (R is H or methyl; (n) is 0-6). The component A preferably contains 50wt.% epoxy compound of formula II (R is H or methyl; (n) is 0-6) in the epoxy resin is preferable as the component A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing epoxy resin composition. The present invention relates to an epoxy resin composition for encapsulation, which is excellent in moisture absorption resistance to solder cracking and particularly excellent in moisture resistance reliability.

[0002]

2. Description of the Related Art In recent years, diodes, transistors, I
As a method for sealing semiconductors such as C and LSI and electronic parts,
For example, a resin encapsulation method by low-pressure transfer molding using epoxy resin or silicone resin has become the mainstream because of its improved reliability, mass production and price advantages.
Among them, in the resin encapsulation method using an epoxy resin, orthocresol-novolak type epoxy resin as a resin component, phenol novolac resin as a curing agent component, tertiary amine, imidazoles as a curing and curing accelerator component for sealing A molding material composed of an epoxy resin composition is most often used. However, recently, IC, LSI, VLSI
As the degree of integration of semiconductors and electronic components has become higher, and the molded products of semiconductor devices have become thinner, the epoxy resin composition for encapsulation described above has not always been sufficient. ..

For example, in a surface-mounting semiconductor device, during mounting, the semiconductor device itself is rapidly exposed to a high-temperature environment, such as being directly immersed in solder, so that package cracks occur in the molded product of the semiconductor device. There is a problem of occurrence. This phenomenon is that after the semiconductor device becomes a molded product, moisture absorbed during storage of the semiconductor device is rapidly vaporized and expanded when it is immersed in high-temperature solder, and the sealing resin cannot withstand it, resulting in package cracking. It is thought to occur. In response to this, improvement of these properties has been made in consideration of improvement of heat resistance and hygroscopicity of the encapsulating resin composition.
Although it has been disclosed and made in Japanese Patent Publication No. JP-A-2003-242242, the above-mentioned improvement of the moisture absorption solder crack resistance and the moisture resistance reliability after the moisture absorption solder treatment is not yet sufficiently satisfactory.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to moisture-absorbing solder cracking resistance that does not cause package cracks when solder is dipped after moisture absorption, and particularly moisture-resistant reliability after solder immersion after moisture absorption. It is intended to provide an epoxy resin composition for encapsulating a semiconductor having excellent properties.

[0005]

The present invention has been made to solve the above-mentioned problems, and has the following general formula [1] having an epoxy resin and a phenolic OH group having a naphthalene skeleton as a functional group. Another object of the present invention is to provide a sealing epoxy resin composition containing the cresol compound curing agent, the phosphorus-based curing accelerator, and the inorganic filler.

[0006]

[Chemical 3]

The present invention will be described in detail below. Examples of the epoxy resin include biphenyl novolac type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and halogenated epoxy resins thereof. For example, it is an epoxy resin having two or more epoxy groups in one molecule, and has an epoxy equivalent of 180 to 220 and a softening point of 6
When the compounds of 0 to 100 ° C. are used alone or in combination and the compounding amount thereof is within the range of 5 to 35% by weight of the encapsulating epoxy resin composition, there is no uniformity in mixing, heating, melting and kneading as a molding material. It can be secured and can be handled well.

Particularly, 50% by weight or more of the epoxy resin is a biphenyl type of the following general formula [2] (R in the formula [2] represents a hydrogen atom or a methyl group, and n represents an integer of 0 to 6). It is preferable to adjust the blending amount of the epoxy resin. 50% by weight
In the above use, the moisture absorption rate is small and the crack resistance in solder immersion after absorbing the moisture is excellent, but in the use of less than 50% by weight, the moisture absorption rate is large and the adhesion to the semiconductor chip is also deteriorated.

[0009]

[Chemical 4]

A phenolic OH having a naphthalene skeleton
It is necessary to use a curing agent of the above-mentioned cresol compound of the general formula [1] having a group as a functional group, and the compounding amount of the curing agent is preferably 30% by weight or more in the proportion of the curing agent. If it is less than 30% by weight, the moisture absorption does not proceed so much and the improvement of the moisture absorption solder crack resistance is not recognized. In addition, a phenol novolac resin, a cresol novolac resin, a resole resin or the like can be used in combination as a curing agent. Among them, a phenol resin having two or more hydroxyl groups in one molecule, having a hydroxyl equivalent of 80 to 120 and a softening point of 60 to 120 ° C., alone or in combination, the compounding amount of these curing agents is for sealing. 2 of epoxy resin composition
When it is used in the range of 25% by weight, it is possible to ensure uniformity in mixing, heating, melting and kneading as a molding material, and it can be handled satisfactorily.

As the phosphorus-based curing accelerator, triphenylphosphine, triphenylphosphite, triphenylphosphate and the like can be used. Further, as other curing accelerators, tertiary amines, imidazoles and the like can be used in combination.

Examples of the inorganic filler include powders of fused silica, crystalline silica, talc, alumina, calcium silicate, calcium carbonate, silicon nitride and the like, which can be used alone or in combination.
However, since it is used for sealing electronic parts, the high-purity inorganic filler has an electric conductivity of 100 μs / cm or less when the 5 g of inorganic filler is extracted with 45 g of pure water at 95 ° C. for 20 hours. Is preferred. Silica is particularly preferable. The compounding amount of the inorganic filler is from 65 to 65 of the epoxy resin composition for sealing.
When it is used in the range of 95% by weight, it is possible to ensure uniformity in mixing, heating, melting and kneading as a molding material, and to handle it satisfactorily.

As the compounding ingredients of the epoxy resin composition for encapsulating a semiconductor of the present invention, in addition to the above, suitable additives, curing and curing accelerators, flame retardants, release agents, colorants, etc. are applied. can do.

Further, in order to form a semiconductor encapsulating epoxy resin composition comprising the above-mentioned compounding ingredients as a molding material, the compounding ingredients are uniformly mixed and manufactured by a usual process of heating, melting, cooling and crushing. The equipment used at this time, for example, mixers, blenders, kneaders, rolls and the like which are commonly used, can be applied as they are.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

[0016]

【Example】

As the epoxy resin of Examples 1 to 4 and Comparative Examples 1 to 4, biphenyl novolac type epoxy resin (YX-4000H manufactured by Yuka Shell Co., epoxy equivalent 1
85, wherein R is a methyl group and n = 0 in the general formula [2]), or, and an epoxy equivalent of 195, a softening point of 65.
As a curing agent for an ortho-cresol-novolak epoxy resin (denoted as O.C.N epoxy resin in the table) at ℃, a cresol compound of the general formula [1] having an OH group equivalent of 140 (manufactured by Nippon Kayaku Co., Ltd. OCN-7000) was used alone or in combination to use a novolac-type phenol resin having a hydroxyl equivalent of 104 and a softening point of 80 ° C. Any one of triphenylphosphine, 2-phenylimidazole, 2-methylimidazole, and DBU was used as a curing accelerator. The respective components and their blending amounts are shown in the upper part of Tables 1 and 2. The unit is parts by weight. The following components were used in common with the other components and their amounts. All units are parts by weight, and will be referred to as "parts" hereinafter.

The inorganic filler of (1) has an average particle size of 14
7 μm of fused silica with an electric conductivity of 3 μs / cm
54 parts, 5 parts of γ-glycidoxypropyltrimethoxysilane as a coupling agent, 21 parts of antimony trioxide as a flame retardant, 14 parts of a brominated epoxy resin having an epoxy equivalent of 400 and a softening point of 65 ° C., and a colorant. 2.5 parts of carbon black and 3 parts of carnauba wax as a release agent were used. The compounding amounts of the above compounding ingredients are uniformly mixed for each example, and the mixture is heated, melted, and kneaded with a mixing roll having a roll temperature of 100 ° C., cooled, and pulverized to obtain an epoxy resin composition for sealing each semiconductor. A molding material was obtained.

Using the molding material of the epoxy resin composition for sealing each semiconductor obtained above, a predetermined mold was attached to a 75-ton transfer molding machine, and the mold temperature was 180 ° C., respectively.
Molding was carried out for a molding time of 60 seconds.

The moisture absorption rate of a test piece having a diameter of 50 mm and a thickness of 3 mm is
The weight change rate of the test piece before and after the treatment at 85 ° C. and 85% relative humidity for 72 hours was calculated. The results are shown in the lower part of Tables 1 and 2.

Moisture-absorbing solder cracks were obtained by sealing and molding 12 pieces of 60QFP molded products using a 42Q 60QFP leadframe mounted with evaluation elements each having a comb-shaped aluminum wiring circuit arranged on the surface of a silicon chip. After being treated as a test piece and treated at 85 ° C and 85% relative humidity for 72 hours, 250
It was immersed in a solder bath at a temperature of 10 ° C. for 10 seconds and inspected for appearance cracks. The results are shown in the lower part of Tables 1 and 2 by the number of cracks generated / total number of samples.

Moisture-resistant reliability after moisture-absorption soldering was the same as that of moisture-absorption solder cracks. 12 pieces of 60QFP molded products were used. After treatment for 72 hours at the same temperature of 85 ° C and 85% relative humidity as in the moisture-absorption solder crack test, soldering at 250 ° C After dipping in a bath for 10 seconds and further treating with PCT at 2 atm for 200 hours, the mounted semiconductor chips were evaluated for open defects, and the results are shown in Table 1 and Table 2 at the bottom of Table 1 and Table 2. Indicated.

From the results shown in the lower part of Tables 1 and 2, the curing agent for the cresol compound of the above-mentioned general formula [1] having a phenolic OH group having a naphthalene skeleton as a curing agent as a curing agent and phosphorus-based curing acceleration In the examples containing the agent, after moisture absorption, when immersed in solder, moisture absorption resistance that does not cause package cracks while maintaining good solder crack resistance, especially moisture absorption after solder immersion after moisture absorption It was confirmed that the reliability was excellent.

[0023]

The epoxy resin composition for encapsulation of the present invention absorbs moisture after absorbing moisture, and does not cause package cracks when immersed in solder. It is possible to obtain a semiconductor device and an electronic component that are excellent in the reliability of the moisture resistance.

[0024]

[Table 1]

[0025]

[Table 2]

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 23/31

Claims (3)

[Claims] 1. An epoxy resin, a curing agent for a cresol compound of the following general formula [1] having a phenolic OH group having a naphthalene skeleton as a functional group, a phosphorus-based curing accelerator, and an inorganic filler are contained. An epoxy resin composition for encapsulation, comprising: [Chemical 1] 2. An epoxy resin represented by the following general formula [2] (wherein R represents a hydrogen atom or a methyl group, and n represents an integer of 0 to 6) having a biphenyl skeleton. 2. The epoxy resin composition for encapsulation according to claim 1, wherein the epoxy resin content is 50% by weight or more in the epoxy resin. [Chemical 2] 3. The encapsulating epoxy resin composition according to claim 1, wherein the cresol compound curing agent is contained in an amount of 30% by weight or more in the curing agent.