JPH0786463A - Epoxy resin composite for sealing semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a cured material excellent in fluidity besides in solder heat resistance and in a hygroscopic property besides in solder heat resistance by containing epoxy resin to be expressed by a specific formula in an epoxy resin composite consisting of epoxy resin polyvalent phenolic compound and an inorganic filler. CONSTITUTION:This is an epoxy resin composite consisting of epoxy resin, polyvalent phenolic compound and an inorganic filler while containing epoxy resin to be expressed by a crystalline formula which is a solid at a cold temperature as an epoxy resin component. Since this epoxy resin has an extremely low viscosity in a molten state, it holds excellent molding fluidity besides allowing high filling with silica so that a crack-proofness of a package obtained by sealing a semiconductor element by this composite can be sharply improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition which is suitable for encapsulation of semiconductor elements and the like which gives a cured product having excellent fluidity, low hygroscopicity and solder heat resistance. is there.

[0002]

2. Description of the Related Art Conventionally, a resin composition containing an epoxy resin as a main component has been widely used as a semiconductor sealing material.
In recent years, as a method of mounting components on a printed circuit board, a shift from a conventional insertion method to a surface mounting method is progressing. In the surface mounting method, package cracking caused by rapid volume expansion of moisture absorbed by heating the entire package to the solder temperature has become a serious problem. Furthermore, in recent years, the high integration of semiconductor elements, the increase in element size, and the miniaturization of wiring width are rapidly progressing.
The problem of package cracks is becoming more serious.
As a method for preventing package cracks, there are methods such as toughening the resin structure, increasing the strength by increasing the filling of silica, and reducing the water absorption rate, but these are not yet sufficient.

In order to overcome the above problems, it has been proposed to use an epoxy resin having a low hygroscopicity and a low viscosity. As the low-viscosity epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin and the like are generally widely used. Among these epoxy resins, those having low viscosity are liquid at room temperature, and resin compositions for transfer molding are used. It is difficult to make a thing. Furthermore, these epoxy resins are not sufficient in terms of heat resistance, mechanical strength and moisture resistance.

Further, Japanese Examined Patent Publication No. 4-7365 discloses an epoxy resin composition for semiconductor encapsulation containing a biphenyl epoxy resin as a main component, which has improved handling workability, heat resistance and toughness. However, there is a problem in terms of low hygroscopicity.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an epoxy resin composition for encapsulating a semiconductor device, which provides a cured product having excellent fluidity, low hygroscopicity, and solder heat resistance. Especially.

[0006]

That is, the present invention is as follows.
(A) Epoxy resin (b) Polyhydric phenolic compound (c) An epoxy resin composition comprising an inorganic filler, which is a crystalline general formula (1) which is solid at room temperature as an epoxy resin component.

[Chemical 2] An epoxy resin composition for semiconductor encapsulation, comprising an epoxy resin represented by:

The epoxy resin represented by the above general formula (1) has the following general formula (2)

[Chemical 3] It is produced by reacting a bisphenol compound represented by and epihalohydrin. This reaction can be carried out in the same manner as a usual epoxidation reaction.

For example, a bisphenol compound is dissolved in an excess of epichlorohydrin or the like, and then sodium hydroxide,
5 in the presence of an alkali metal hydroxide such as potassium hydroxide
0 to 150 ° C, preferably 1 to 60 ° C to 120 ° C
A method of reacting for 10 hours can be mentioned. The amount of epihalohydrin used at this time is 0.8 to 2 mol, preferably 0.9 to 2 mol, per 1 mol of the hydroxyl group of the bisphenol compound.
It is in the range of 1.2 moles. After completion of the reaction, excess epi distills off the rhohydrin, dissolves the residue in a solvent such as toluene or methyl isobutyl ketone, filters and rinses with water to remove inorganic salts, and then distills off the solvent to remove the epoxy. It can be a resin.

However, since these epoxy resins are usually liquid even at room temperature, it is necessary to crystallize them for use in the present invention. Examples of the crystallization method include crystallization using a solvent or crystallization by adding a previously prepared crystal seed. In the method using a solvent, alcohols such as methanol, ethanol and isopropyl alcohol, and hydrocarbon solvents such as pentane, hexane and heptane are preferably used as the solvent species.

In the general formula (1), the substituents R ₁ to
R ₄ represents a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 6 carbon atoms. Examples of the hydrocarbon group include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, and a tert- group.
Examples include an amyl group and a phenyl group. In addition, the substituent R
_{5 to} R ₈ are hydrogen atoms or methyl groups. The preferable range of melting point of the crystalline epoxy resin used is 40 to 13
The temperature is 0 ° C, and more preferably 50 to 120 ° C. If it is lower than this, there is a problem such as blocking during storage, and if it is higher than this, the solubility is poor and the mixing property with the curing agent is reduced.

Melting point, viscosity, reactivity and heat resistance of the cured product,
Taking moisture resistance into consideration, examples of preferable crystalline epoxy resin include crystalline 1,4-bis (4-hydroxycumyl) benzene diglycidyl ether compound having a melting point of 55 to 75 ° C. and a melting point of 75 to 75 ° C. Crystalline 1, which is 95 ℃
Examples thereof include diglycidyl ether of 4-bis (3-methyl-4-hydroxycumyl) benzene. Those having a melting point lower than the above range are not preferable because they have a large amount of dimer or higher oligomer components and have problems of increased viscosity and reduced heat resistance.

As the curing agent used in the resin composition of the present invention, one having a phenolic hydroxyl group is used.
For example, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcin, divalent phenols such as naphthalenediol, tris- (4-hydroxyphenyl). methane,
Trivalent or higher phenols represented by 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolac, o-cresol novolac, naphthol novolac, polyvinylphenol, and the like, further phenols, naphthols, Divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcin, naphthalenediol are converted into formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde. , A polyhydric phenolic compound synthesized by condensation with a condensing agent such as p-xylylene glycol. These curing agents may be used alone or in combination of two or more.

In addition to the epoxy resin used as an essential component of the present invention, a usual epoxy resin having two or more epoxy groups in the molecule may be used in combination in the resin composition of the present invention. For example, divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinno, resorcin, or tris- (4 -Hydroxyphenyl)
Derived from trivalent or higher phenols such as methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolac, o-cresol novolac, or halogen-valent bisphenols such as tetrabromobisphenol A There is a glycidyl ether compound. These epoxy resins may be used alone or in combination of two or more, and the compounding amount of the epoxy resin according to the present invention is preferably in the range of 50 to 100% by weight in the whole epoxy resin.

An inorganic filler is added to the resin composition of the present invention. As the inorganic filler, for example, spherical or crushed fused silica, silica powder such as crystalline silica,
Alumina powder, glass powder or the like is used, and the amount thereof is preferably 70% by weight or more, more preferably 75% by weight or more from the viewpoint of low hygroscopicity and improvement of solder heat resistance.

If necessary, a conventionally known curing accelerator can be used in the resin composition of the present invention. Examples include amines, imidazoles, organic phosphines, Lewis acids and the like. The addition amount is in the range of 0.2 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin.

Further, if necessary, the resin composition of the present invention contains a release agent such as carnauba wax and OP wax, and γ.
-A coupling agent such as glycidoxypropyltrimethoxysilane, a coloring agent such as carbon black, a flame retardant such as antimony trioxide, a stress reducing agent such as silicon oil, and a lubricant such as calcium stearate can be used.

[0017]

EXAMPLES The present invention will be described in more detail below with reference to examples. Reference Example 1 1,4-bis (4-hydroxycumyl) benzene 120
g was dissolved in 720 g of epichlorohydrin, 0.3 g of benzyltriethylammonium chloride was further added, and under reduced pressure (about 150 mmHg), 56.6 g of 48% aqueous sodium hydroxide solution was added dropwise at 70 ° C. over 4 hours. The water generated during this period was removed from the system by azeotropic distillation with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the dropping was completed, the reaction was continued for another hour. Then, the salt produced by filtration is removed, and after further washing with water, the epichlorohydrin is distilled off to give a colorless transparent liquid resin 1
51 g were obtained. Pre-prepared with the obtained resin 1,
Fine powder crystals of a diglycidyl ether compound of 4-bis (4-hydroxycumyl) benzene were added, and the mixture was allowed to stand at 30 ° C. to obtain a white crystalline epoxy resin. Epoxy equivalent was 243 and melting point was 64.5 ° C. Two
The viscosity in m-cresol (30% by weight) at 5 ° C. was 28 cP.

Reference Example 2 120 g of 1,4-bis (3-methyl-4-hydroxycumyl) benzene, 48% aqueous sodium hydroxide solution 53.
The reaction was performed in the same manner as in Reference Example 1 using 4 g to obtain 150 g of a white crystalline epoxy resin. Epoxy equivalent was 245 and melting point was 88.5 ° C. The viscosity in m-cresol (30% by weight) at 25 ° C is 64.5.
It was cP.

Examples 1 and 2 The epoxy resin obtained in Reference Example 1 was used as the epoxy resin component, phenol novolac resin (PSF-4300 manufactured by Gunei Chemical Co., Ltd.) as a curing agent, and crushed silica (as a filler). An average particle size of 16 μm) or spherical silica (average particle size of 22 μm), triphenylphosphine as a curing accelerator, γ-glycidoxypropyltrimethoxysilane as a silane coupling agent, and other additives are kneaded in the composition shown in Table 1. Then, an epoxy resin composition was obtained. This epoxy resin composition was molded at 175 ° C. and post-cured at 175 ° C. for 12 hours to obtain a cured product test piece, which was then subjected to various physical property measurements. In addition, an 84-pin IC is molded using the present epoxy resin composition, and after post-curing 85
Moisture was absorbed under the conditions of ° C and 85% RH for 24 hours, 48 hours and 72 hours, and immersed in a solder bath at 260 ° C for 10 seconds, and cracks in the package were observed. The results are shown in Table 1.

Example 3 Using the epoxy resin obtained in Reference Example 2 as the epoxy resin component, compounding, kneading, molding and evaluation were carried out in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 Using an o-cresol novolac type epoxy resin (softening point 71 ° C.) as an epoxy resin component, an epoxy resin composition was obtained in the same manner as in Example 1 and then molded and evaluated. The results are shown in Table 1.

[0022]

[Table 1]

[0023]

Since the epoxy resin used in the present invention has an extremely low viscosity in the molten state, it retains excellent molding fluidity and can be highly filled with silica.
The crack resistance of a package obtained by sealing a semiconductor device with the composition is significantly improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area C08L 63/00 NKT H01L 23/31

Claims (3)

[Claims] 1. An epoxy resin composition comprising (a) an epoxy resin, (b) a polyhydric phenolic compound, and (c) an inorganic filler, which is a crystalline general formula (Eq. 1) [Chemical 1] An epoxy resin composition for semiconductor encapsulation, comprising an epoxy resin represented by: 2. The melting point of the crystalline epoxy resin is 50 to 1
The epoxy resin composition for semiconductor encapsulation according to claim 1, which is in a range of 20 ° C. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, which contains an inorganic filler in an amount of 75% by weight or more.