JPS6198726A - Epoxy resin composition for sealing electronic parts - Google Patents

Abstract

PURPOSE:The title resin composition that is composed of a specific epoxy resin, a curing agent and inorganic fillers, thus showing high moisture and heat resistance with low thermal expansion. CONSTITUTION:The objective composition is obtained by using (A) an epoxy resin of the formula (R is H, methyl; n is 0-6), (B) a curing agent such as methyl nadic anhydride, 2-methylimidazole, or 2-(dimethylaminomethyl)-phenol and (C) inorganic fillers, preferably silica powder. The resin A is obtained by reaction of 4,4'-bishydroxyphenyl or 4,4'-bishydroxy-3,3'-5,5'-tetramethylbi phenyl with an epihalohydrin or -methylepihalohydrin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an epoxy resin composition that has good moisture resistance and is suitable for sealing electronic components.

[Prior art and its problems]

2. Description of the Related Art In semiconductor devices such as transistors and integrated circuit elements, resin encapsulation methods have been attempted for the purpose of improving reliability and economic efficiency. Although this resin sealing method has the great advantage of being able to seal easily by using epoxy resin, for example, it has poor stability against moisture (moisture resistance), making it difficult to sufficiently improve the reliability of semiconductor devices. This is an inconvenience.

As a method to improve the above-mentioned disadvantages, semiconductor devices that are resin-sealed by treating the surface of the semiconductor element to be resin-sealed with a silane coupling agent and then sealing it with a boxy resin or using a sealing agent. Although it is possible to improve the moisture resistance of

[Purpose of the invention]

The present invention was made in view of these circumstances, and its purpose is to provide a composition having appropriate fluidity, and a cured product thereof having excellent heat resistance and moisture resistance, as well as thermal expansion resistance. It is an object of the present invention to provide an epoxy resin composition for encapsulating electronic components, which has a relatively low efficiency.

[Summary of the invention]

The present inventors, as a result of intensive studies to achieve the above object, have found that bishy, droxybiphenyl-based epoxy resin,
The epoxy resin composition consisting of a hardening agent and an inorganic filler has appropriate fluidity and is easy to handle, and the cured product has good moisture resistance and has an excellent aluminum corrosion ratio when encapsulating semiconductor devices etc. The present invention was completed based on the discovery that the following is true.

That is, the present invention provides: 1. (a) an epoxy resin represented by the general formula (in the formula, R represents a hydrogen atom or a methyl group, and n represents an integer of θ to 6); (b) curing; (c) an inorganic filler, an epoxy resin composition for encapsulating electronic components, characterized in that it contains 50% by weight or more of the inorganic filler as component (c); The epoxy resin composition for encapsulating electronic components according to item 1.

The bishydroxybiphenyl epoxy resin as component (a) in the present invention is represented by the general formula (wherein R represents a hydrogen atom or a methyl group, and n represents an integer from 0 to 6). This resin is 4,4'-bishydroxyphenyl or 4,4'-bishydroxy-3,3',
s'.

It can be obtained by reacting 5-tetramethylbiphenyl (hereinafter, both are represented by bishydroxybiphenyl) with epihalohydrin or β-methylepihalohydrin (hereinafter, both are represented by epihalohydrin).

Specifically, (i), an excess of bishydroxybiphenyl and shrimp halohydrin is reacted with F' coexisting with an alkali metal hydroxide, and an addition reaction of shrimp halohydrin to bishydroxybiphenyl and a ring-closing reaction to form an epoxy ring are carried out. One-step method (ii) for producing a polyepoxy compound by simultaneously carrying out the addition reaction of bishydroxybiphenyl and excess shrimp halohydrin in the presence of a basic catalyst,
Next, a two-step method may be mentioned in which an alkali metal hydroxide is added and a ring-closing reaction is performed to produce a polyepoxy compound.

Examples of the shrimp halohydrin include epichlorohydrin, shrimp bromohydrin, β-methylepichlorohydrin, β-methylevibromohydrin, β-methyleviodohydrin, and the like, but epichlorohydrin is generally used.

Further, as the alkali metal hydroxide, caustic potash and caustic soda can be used, and these can be used as solids or
Added as a ~50% alkaline aqueous solution.

As the basic catalyst, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, triethylmethylammonium chloride, tetraethylammonium iodide, and cetyltriethylammonium bromide can be used.

In the one-stage method, the temperature is 60 to 150°C, preferably Fi8
Curling is carried out at a temperature in the range 0-120°C. The alkali metal hydroxide is used in an amount of at least equimole, preferably 1.05 to 1.5 times, per equivalent of hydroxide of the biphenyl derivative. The amount of shrimp halohydrin to be added to bishydroxybiphenyl is 2 times to 8 times by mole.

In addition, in the two-stage method, the first stage reaction is 90 to 15
It is carried out at a temperature of 0°C, preferably 100-140°C. The amount of epihalohydrin used is 2 to 20 times the molar amount Fi, preferably 3 to 8 times the molar amount of bishydroxybiphenyl, and the epihalohydrin used in excess can be reused by recovering it by distillation. Further, the basic catalyst is used in mass production in an amount of 0.002 to 0.5 mol% based on the phenolic hydroxyl group of bishydroxybiphenyl.

The reaction temperature in the latter stage is 60 to 150°C, preferably 80 to 120°C.
The alkali metal hydroxide yJ is used in an equimolar amount to 1.1 times the molar amount of the produced halohydrin.

These first-stage and second-stage reactions may be carried out in the presence of an inert organic solvent such as methyl isobutyl ketone, methyl ethyl ketone, or toluene.

After the reactions (1) and (if) are completed, the reaction product is washed with warm water to remove an alkali metal salt such as common salt, and then purified by distilling off water. Alternatively, the reaction product is dissolved in an organic solvent that is insoluble or poorly soluble in water, such as methyl isobutyl ketone, methyl ethyl ketone, toluene, etc., and this solution is brought into contact with water or hot water to dissolve inorganic impurities such as common salt in the aqueous phase. Thereafter, the organic solvent is distilled off to perform purification.

The epoxy resin represented by the above general formula obtained in this way does not consist only of the n=00 compound, even when a large excess of shrimp halohydrin is used;
It usually contains a polyepoxy compound of 1 to 6 in a proportion of 20% by weight or less. In the general formula of the present invention, n is an integer of 0 to 6, but if n is larger than 6, the softening point will be high, which is disadvantageous in terms of workability, and therefore it cannot be used.

It is preferable that n is θ~3.

The softening point of the epoxy resin represented by this general formula depends on its degree of polymerization and molecular weight distribution, but for example, R
When R is all CH3, it is 83 to 185°C, and when R is all H, it is liquid to 140°C.

The epoxy resin used in the present invention is a bishydroxyl-vinyl-based epoxy resin represented by the above general formula, but it can be used in combination with other epoxy resins if necessary. Examples of general-purpose epoxy resins that may be blended as necessary include the following.

(i) diglycidyl ether of bisphenol A;
The products include Epicoat 827, 828, 834, 864, and 100 from Yuka Shell Epoxy Co., Ltd.
1, 1004, 1007, 1031, Chipa Araldite GY250, 6099, Union Carbide ER, L2774, Dow Chemical DER33
2, 331, 661, (all of the above are product names), etc.

(ii) Epoxyphenol novolak: The product is Epicoat 15 from Yuka Shell Epoxy Co., Ltd.
2, 154, DOW Chemical Company DEN438, 44
8. Chipa's Araldai) EPN1138, EPN1139
(All of the above are product names) etc.

(iii) Epoxy cresol novolac; its products include Ciba's Araldite ECN1235 and 1
273, 1280 (all of the above are product names), etc.

In addition, epoxy resin obtained from phthalic acid or hexahydrophthalic acid and epichlorohydrin, epoxy resin obtained from rosehydroxybenzoic acid and epichlorohydrin, epoxy resin obtained from aromatic amine such as toluidine or aniline and epichlorohydrin, vinyl cyclohexene dioxide , 1,4-butanediol diglycidyl ether, 1,6-hexanesiol diglycidyl ether, etc. However, these epoxy resins contain free sodium ion and chloride ion content, which can cause a decrease in moisture resistance. It is desirable that each of these amounts to be less than t0 ppm.

The curing agent or curing accelerator used as component (b) of the present invention includes acid anhydride type, imidazole type, phenol type, etc., and examples thereof include the following.

(+) Methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, pyromellitic anhydride, tetrahydrophthalic acid hydrate, glutaric anhydride, phthalic anhydride, benzophenonetetracarboxylic anhydride , cyclopentanetetracarboxylic anhydride,
acid anhydrides such as

(ii) Imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, and 2-ethyl-4-methylimidazole.

(iii) z-(dimethylaminemethyl)phenol,
2.4.6-) Phenols such as lis(dimethylaminomethyl)phenol, or novolac phenols (e.g., Gunei Kagakusha brand name MP-617, 120M)
); alkylphenol novolaks, such as cresol novolak, butylphenol novolac, nonylphenol-rutuvolak; polyalkenylphenols, such as poly-p-vinylphenol, poly-p-impropenylphenol.

The ratio of these curing agents is usually 10 parts of epoxy resin.
The amount is 3 to 120 parts by weight relative to 0 parts by weight, and is generally blended in so-theoretical equivalents. In addition, the amount of the curing accelerator is 0.02 to 1.0% by weight in the epoxy resin composition.
It is preferable that

The inorganic filler as component (e) used in the present invention may be any inorganic filler that is normally used as an inorganic filler. Such inorganic fillers include fused silica powder, crystalline silica powder, quartz glass powder, talc, calcium silicate powder, zirconium silicate powder, alumina powder, calcium carbonate powder, clay powder, barium sulfate powder, and glass fiber. etc., and one or more than 21 selected from the group consisting of these are used,
Particularly preferred is silica powder.

The amount of the inorganic filler blended may be an amount sufficient to impart the desired elastic modulus, linear expansion coefficient, glass transferability, etc. to the cured product depending on the type of inorganic filler blended.
It is preferable that the resin composition contains 50 to 85% by weight. If it is less than 50%, the coefficient of linear expansion will increase, while if it exceeds 85%, the fluidity of the resin composition will decrease.

In the present invention, a mold release agent, a coloring agent, a coupling agent, a flame retardant, etc. may be added as needed. Examples of mold release agents include natural waxes, synthetic waxes, higher fatty acids and their metal salts, paraffin, etc. Coloring agents include Nyoribon, etc., and flame retardants include, for example, antimony dioxide, Antimony oxide, phosphoric acid, phosphorus compounds, etc. are used.

〔Effect of the invention〕

According to the present invention, it is possible to obtain an epoxy resin composition for sealing electronic components whose cured resin has excellent heat resistance and moisture resistance and also has a relatively small coefficient of thermal expansion. Therefore, when the resin composition is used for sealing electronic components such as semiconductor devices, it can provide excellent sealing reliability and stability.

[Embodiments of the invention]

Production of bishydroxybiphenyl-based epoxy resin Production Example 1 Epoxy resin A 4.4'-bis-hydroxy-3,3'
,5. s'-tetramethyl-biphenyl 121.29 (
0.5 mol), epichlorohydrin 3702 (4 mol)
, 2.429 parts of tetramethylammonium chloride (2 parts per biphenyl) was charged, and the oil bath was heated to 130°C.
The addition reaction was carried out under reflux for 2 hours under open conditions.

The contents were then cooled to 60'C and fitted with a moisture removal device. Sodium hydroxide 42 f (1,05 mol)
was added to reactor E, 5, the reaction temperature was 50 to 65°C, and the degree of vacuum was 10.
The ring-closing reaction was carried out by continuously azeotropically removing the produced water under the conditions of collecting 0 to 20,011 Il. The reaction end point was defined as the point at which the produced water reached 18 d (1.5 hours).

After collecting excess epichlorohydrin under reduced pressure, toluene soo*z was added and washed three times with 1 ton of water to remove the generated common salt, remaining alkali, and catalyst gold. Toluene was removed under reduced pressure using a rotary evaporator to obtain 4,4'-bis(2,3-epoxygloboxy) as a light brown solid.
-3,3',5,5'-tetramethylbiphenyl 166
．． 1 f was obtained. The properties of the product were as follows.

Softening temperature 283~93℃ Epoxy @:203 One change, +01. .

-, Pa °- 1, °-17 Production example 2 Epoxy resin B 4.4'-bis hydroxy-3+3'
-515'-tetramethyl-biphenyl 121.2f
(0.5 mol), epichlorohydrin 259? (2,
8 mol), tetramethylammonium chloride 2.4f
was charged and the reaction was carried out in the same manner as in Production Example 1 to obtain a light brown solid product at 150? Obtained. The properties of the product were as follows.

Softening@degree: 120-130°C Epoxy Jil: 580 Examples 1-2, Comparative Example 1 Epoxy resin A and B1 obtained in Production Example 1.2 Bisphenol A type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.: E-
828 (trade name), acid anhydride curing agent: Kayahard MCD
(trade name manufactured by Nippon Kayaku Co., Ltd.), curing accelerator: I-benzyl-2-methyl-imidazole, fused silica, silane coupling agent, and carbon black in the proportions shown in Table 1. A composition was prepared. Next, the prepared epoxy resin composition is used to coat an IC,
A moisture resistance test was conducted using a pressure tester (133° C., 3 atm) to check for current failure due to corrosion of the aluminum electrode. Table 2 shows the ratio of the number of test pieces (denominator) to the number of defective items (numerator).

Further, the water absorption coefficient and thermal expansion coefficient of the cured product are also shown in Table 2.

(Margin below) Table 1

Claims (1)

[Claims] 1. (a) Epoxy resin represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents a hydrogen atom or a methyl group, and n represents an integer from 0 to 6.) 1.) A curing agent; (c) An inorganic filler. An epoxy resin composition for encapsulating electronic components. 2. The epoxy resin composition for encapsulating electronic components according to claim 1, which contains 50% by weight or more of the inorganic filler as component (c).