JPH0337221A - Epoxy resin composition for semiconductor sealing - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition for semiconductor sealing having high heat resistance and high cracking resistance, excellent humidity resistance and good moldability by using a specified novolac resin as an epoxy resin curing agent. CONSTITUTION:An epoxy resin composition comprising an epoxy resin, an epoxy resin curing agent and an inorganic filler, wherein the curing agent comprises a novolac obtained by condensing dihydroxynaphthalene with an aldehyde selected from among those of formulas I-V in the presence of an acid catalyst and having a free Na<+> content and a free Cl<-> content such of 10ppm or below. In those formulas, R<1> is a hydrogen atom, a 1-5C alkyl, a phenyl or a halogen-substituted phenyl; (m) is an integer of 0-8; R<2> is a hydrogen atom, a 1-5C alkyl or a phenyl; and R<3> is a hydrogen atom, a 1-5C alkyl or a methoxy. It is desirable to add a plasticizer (e.g. polybutadiene or polysiloxane oil or rubber) to the above composition.

Description

Detailed Description of the Invention (a) Object of the Invention (Field of Industrial Application) The present invention provides an epoxy resin composition for semiconductor encapsulation that has excellent heat resistance, moisture resistance, and crack resistance, and has good moldability. relating to things.

(Prior art) Conventionally, the method of sealing with an epoxy resin composition has been used for sealing semiconductor devices because it is more advantageous than the hermetic sealing method using glass, metal, or ceramic in terms of reliability, productivity, cost, etc. , was the most commonly used.

The epoxy resin for semiconductor encapsulation is mainly composed of orthocresol novolac type epoxy resin.
The epoxy resin curing agent mainly uses a novolak type phenolic resin. However, in recent years, as semiconductor devices have become more highly integrated, the device area has become larger and the package shape has also become thinner. Problems such as deformation of aluminum wiring can no longer be ignored. Furthermore, the mounting method is changing from pin insertion to surface mounting, and semiconductor encapsulating materials are now required to have even higher heat resistance, moisture resistance, and crack resistance.

As a means of solving such problems, methods are used in which various rubber-like resins are added as plasticizers or a large amount of inorganic filler is blended into epoxy resin compositions using epoxy enol resins as the main component. However, although this method can improve crank resistance, it has problems such as deterioration of other physical properties and markedly poor fluidity during molding.

(Problem of the Invention) An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation that has high heat resistance and crack resistance, as well as excellent moisture resistance and good moldability.

(B) Structure of the invention (means for solving the problem) As a result of repeated research in order to solve the above problems, the present inventors achieved the objective by using a specific epoxy resin curing agent as a curing agent. I was able to do so.

That is, the epoxy resin composition for semiconductor encapsulation of the present invention is an epoxy resin composition containing an epoxy resin, an epoxy resin curing agent, and an inorganic filler, in which dihydroxynaphthalene and the following general formula are used as the epoxy resin curing agent. A novolac type resin obtained by condensing an aldehyde selected from the aldehydes represented by (1) to (V) in the presence of an acid catalyst, and containing free Na'',
This composition is characterized by using a novolac type resin containing 10 ppm or less of Cl.

General formula (■): R'-(IIO... (1) In formula (1), R' is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a halogen-substituted phenyl group.

General formula (II): 0CR(-CH□→,C)10 (II) In II (II), m is an integer of 0 to 8.

-Crest hole (■): R''-CH=C)l-CHO (I[[) In formula (II[), R2 is a hydrogen atom, carbon number 1 to 5
is an alkyl group or a phenyl group.

- Crest (■): R3 In formula (IV), R3 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a methoxy group.

- Pattern hole (■): As the raw material dihydroxynaphthalene for producing the epoxy resin curing agent in the present invention, for example, 1.5-
Dihydroxynaphthalene, 1.6-dihydroxynaphthalene, 1.7-dihydroxynaphthalene, 2.6-dihydroxynaphthalene, 2.7-dihydroxynaphthalene, 1.4-dihydroxynaphthalene, 1,2-dihydroxynaphthalene, ■, 3-dihydroxy Naphthalene, 2
．． Examples include 3-dihydroxynaphthalene.

Examples of the aldehyde represented by the above-mentioned formula (1) for producing the epoxy resin curing agent in the present invention include formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, valeraldehyde, capronaldehyde, benzaldehyde, chlorobenzaldehyde,
Examples include brombenzaldehyde. Among these, formaldehyde is particularly preferred.

Further, examples of the aldehyde represented by the above-mentioned -Momonen (II) include glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipinealdehyde, pimelinaldehyde, sperinaldehyde, azelaic aldehyde, and sebacinaldehyde. Among these, glyoxal is particularly preferred.

Examples of the aldehyde represented by the above-mentioned formula (II) include acrolein, crotonaldehyde, and cinnamaldehyde, with crotonaldehyde being particularly preferred.

Further, examples of the aldehydes represented by the above-mentioned symbol (IV) include p-hydroxybenzaldehyde, salicylaldehyde, and methoxyhydroxybenzaldehyde.

Further, examples of the aldehyde represented by the symbol (V) include phthalaldehyde, isophthalaldehyde, and terephthalaldehyde.

The novolac resin as an epoxy resin curing agent in the present invention is composed of the dihydroxynaphthalene and the
It is obtained by condensation reaction with an aldehyde selected from aldehydes represented by 1) to (V). The condensation reaction is carried out in the presence of a condensation catalyst, and examples of the condensation reaction catalyst include mineral acids such as hydrochloric acid and sulfuric acid, organic acids such as oxalic acid and toluenesulfonic acid, boron trifluoride, and boron trifluoride. Examples include ether complexes, aluminum chloride, tin salts, zinc chloride, iron chloride, Lewis acids such as titanium chloride, and the like. The amount of condensation catalyst used is 0.1 to 5% by weight based on dihydroxynaphthalene.

This condensation reaction is usually carried out by heating at a temperature of 50 to 250°C, preferably 50 to 180°C, for 1 to 10 hours. This condensation reaction may be carried out using aromatic solvents such as dungzene, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, and diphenyl ether, ethers such as ethylene glycol, diethylene glycol, tetrahydrofuran, and dioxane, methanol, ethanol, isopropanol, etc., as necessary. Alcohols, ketones such as methyl ethyl ketone and methyl isobutyl ketone, carboxylic acids such as acetic acid and propionic acid, or a mixed solvent of two or more selected from these solvents and water can be used.

The novolac type resin thus obtained usually contains a considerable amount of ionic impurities due to the condensation reaction catalyst, etc., so it is desirable to purify it by washing with water or the like. It is well known that ionic impurities in the curing agent cause corrosion of aluminum wiring in semiconductor devices, and deteriorate reliability in deterioration tests and the like under high temperature and high humidity conditions. The present inventors investigated the influence of ionic impurities, particularly free N1 and C1-, on the reliability of semiconductor devices in the novolak resin used in the present invention, and found that the free It has been found that the epoxy resin composition of the present invention can substantially avoid corrosion problems of aluminum wiring of semiconductor devices, etc., when Na'' and (4-) are each 10 ppm or less. Free N1 and CQ- are determined by atomic absorption spectrometry and silver nitrate solution titration of N1 and Cff1- extracted into pure water when a novolac type resin is heated in pure water at 95°C for 20 hours. It is expressed as weight ppm of Ha+ and Cl- in the novolac resin.

The epoxy resin composition for semiconductor encapsulation of the present invention uses the specific novolak type resin thus obtained as the main component of the epoxy resin curing agent, and preferably the entire amount of the epoxy resin curing agent is To be applied by specific epoxy resin curing agents.

Furthermore, the epoxy resin composition for sealing of the present invention further contains an epoxy resin and an inorganic filler as essential components.

There are no particular restrictions on the epoxy resin, and epoxy resins commonly used in sealing epoxy resins, such as novolac-type epoxy resins such as cresol volac-type epoxy resin, can be used.

Further, an epoxy resin obtained by reacting the above-mentioned novolac type resin such as epichlorohydrin used as a curing agent in the present invention can also be used as the epoxy resin of the present invention.

In addition, examples of the inorganic filler include fused silica,
Examples include crystalline silica, glass powder, alumina, and zircon.

Furthermore, it is desirable to incorporate a plasticizer into the epoxy resin composition for sealing of the present invention, and examples of the plasticizer include organic rubbers such as polybutadiene and polyisoprene, polysiloxane oils, and rubbers. It will be done. In addition, some of these plasticizers have epoxy groups,
Those modified with amino groups, carboxyl groups, aliphatic hydroxyl groups, aromatic hydroxyl groups, isocyanate groups, etc. can also be used. It is also possible to modify the epoxy resin or epoxy resin curing agent used in the present invention with these groups.

Furthermore, the epoxy resin composition for sealing of the present invention may contain a curing accelerator, a mold release agent, a flame retardant, a coupling agent, and the like, if necessary.

Examples of the curing accelerator include imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole, amines such as 2,4.6-)lis(dimethylaminomethyl)phenol, benzyldimethylamine, and tributyl Examples include organic phosphorus compounds such as phosphine and triphenylphosphine.

Examples of the mold release agent include natural waxes, synthetic waxes, higher fatty acids, metal salts of higher fatty acids, and paraffin.

In addition, as the flame retardant, a part of the epoxy resin may be a brominated epoxy resin, for example, a brominated phenol novolac type epoxy resin, tetrabromobisphenol A, etc.
It may be used as a type epoxy resin, or may be blended with antimony dioxide, triphenyl phosphate, etc.

Although various methods can be used to prepare the epoxy resin composition of the present invention, a melt mixing method using a mixing roll or an extruder is preferred for boat fishing because it is simple.

(Examples etc.) Below, novolak resin production examples, examples, and comparative examples are given and further detailed.

Novolak resin production example 1 In a reactor equipped with a thermometer, a stirrer, and a condenser, 1.
160 g of 6-dihydroxynaphthalene, formalin (
37%) 24g, p-)luenesulfonic acid monohydrate 1
．． Prepare 9g, 160g of 1,4-dioxane, 100g
After reacting at ``C'' for 5 hours, 25 wt% Na01l
Add 1.6 g to neutralize P-1 luenesulfonic acid,
Change the condenser to a cooling separator to reduce the internal temperature to 100°C
The temperature was gradually raised to 150''C, and then the pressure inside the system was reduced to remove water and solvent.
After washing with water to remove ionic impurities, MIBK was removed under heating and reduced pressure. As a result, 156 g of novolak resin was obtained. Its softening point was 105°C, N1 was 2 ppm+, and C1- was 1 pPII+ or less.

Novolac Resin Production Example 2 In place of formalin in Production Example 1, 22 g of glyoxal (40%) was used, and otherwise the reaction was carried out in the same manner as in Production Example 1, and the same treatment was carried out.

155 g of novola resin was obtained, the softening point of which was 11
0°C, Na'' is 2ppmSt, e- is 1p
It was below PII+.

Novolank Resin Production Example 3 14 g of crotonaldehyde was used instead of formalin in Production Example 1, and the reaction was otherwise carried out in the same manner as in Production Example 1, and the same treatment was carried out. 162 g of novolak resin was obtained, the softening point of which was 105°C, and the Na'' content was 2 ppm.
, Cj! - was 1 ppm or less.

Novolac Resin Production Example 4 The reaction was carried out in the same manner as in Production Example 1 except that 37 g of salicylaldehyde was used instead of formalin in Production Example 1, and the same treatment was carried out. 180 g of novolac resin was obtained, its softening point was 105°C, and N1 was 2 ppn+
, C1- was 1 ppm or less.

Novolac Resin Production Example 5 In place of formalin in Production Example 1, 20 g of terephthalaldehyde was used, and the reaction was otherwise carried out in the same manner as in Production Example 1, and the same treatment was carried out. As a result, 166 g of novolak resin was obtained, the melting point of which was 115°C, and the Na'' content was 2.
ppm and C1- were 1 ppm or less.

Novolac resin production example 6 In a reactor similar to that used in production example 1, 2.7-
Dihydroxynaphthalene 160 g, salicylaldehyde 37 g, P-)luenesulfonic acid monohydrate 1.9 g
After reacting at 150℃ for 6 hours, MIBK4
00 g, and added 11.6 g of 25% Na0t.
-) After neutralizing toluenesulfonic acid, it was washed with water to remove ionic impurities. Next, MIBK was removed under heating and reduced pressure to obtain 175 g of novolak resin. The softening point of the resin was 110''C, N1 was 2 ppm scI2- was below xpp cap.

Novolak resin production example 7 Reacted in the same manner as in production example 1, neutralized with NaOH in the same way,
Water and solvent in the system were removed under heating and reduced pressure.

However, ionic impurities were not removed by washing with water. As a result, 163 g of novolak resin was obtained.

Its softening point is 110 'CSNa' is 14 ppm,
Cl3- was 3 ppm or less.

Novolac resin production example 8 p-) After using 1 g of 36% by weight hydrochloric acid in place of luenesulfonic acid and reacting in the same manner as in production example 1, the solvent and water were removed under heating and reduced pressure. Washing and washing with water were not performed. As a result, 161 g of novolak resin was obtained. Its softening point is 110°C, and Na'' is 1 ppm+
Below, Cff1- was 13 ppm. .

Novolac resin production example 9 After reacting in the same manner as in production example 8, 25% by weight NaOH1
, 6 g was added to neutralize the hydrochloric acid, and the solvent, water, etc. were removed under heating and reduced pressure. However, ionic impurities were not removed by washing with water. As a result, 162 g of novolak resin was obtained. Its softening point is 110'(SNa'' is 14 ppm, C
1- was tspp melon.

Examples 1 to 15 Comparative Examples 1 to 5 Each novolac type resin obtained in Production Examples 1 to 9 above was used, and various additives were blended according to the formulations shown in Tables 1 and 2. 90°C using a kissing roll
After melt-mixing at a temperature of 5 minutes, the obtained molten mixture was taken out in the form of a sheet, cooled, and then crushed to obtain each epoxy resin composition.

Each of the obtained resin compositions was molded by transfer molding, and after curing at 170°C for 5 hours, the following (a)
- (C) tests were conducted and evaluated. The results were as shown in Tables 3 and 4.

(a) A test piece with a glass transition temperature of 5 types φ x 10 mm was measured using a thermomechanical measurement device (TMA).
It was measured by

(II) Cracking resistance Semiconductor elements were sealed by transfer molding using each epoxy resin composition, and 20 molded product pots obtained by further curing at 170"C for 5 hours were tested at -50°C for 15 minutes to
After repeating the temperature cycle of 100 times at 200° C. for 15 minutes, the package was examined for cracks.

(c) Moisture resistant Electric component base 2 obtained by molding an element having two aluminum wirings by transfer molding using each epoxy resin composition and post-curing at 170°C for 5 hours.
For 0 pieces, a bias voltage of 15 V was applied under high pressure steam at 120° C., and the time until 50% failure occurred was determined.

As is clear from Table 3, the epoxy resin compositions of each example, especially the &amp;
Ii material has a high glass transition temperature and excellent heat resistance, and also has excellent crank resistance and moisture resistance. Also, as is clear from Table 4, in order to have good moisture resistance, the free Na+ and C1- in the novolac resin used must be 10p each.
It is essential that it be below pm.

(C) (Effects of the Invention) The epoxy resin composition for semiconductor encapsulation of the present invention has good moldability and can provide encapsulation with excellent heat resistance, moisture resistance, and crank resistance.

Claims (2)

[Claims] (1) In an epoxy resin composition containing an epoxy resin, an epoxy resin curing agent, and an inorganic filler, dihydroxynaphthalene and aldehydes represented by the following general formulas (I) to (V) are used as the epoxy resin curing agent. A novolak type resin obtained by condensation reaction with an aldehyde selected from the following in the presence of an acidic catalyst, and in which free Na^+ and Cl^- are each 10 ppm or less. An epoxy resin composition for semiconductor encapsulation characterized by: General formula (I): R^1-CHO...(I) In formula (I), R^1 is a hydrogen atom and has 1 to 5 carbon atoms.
is an alkyl group, phenyl group or halogen-substituted phenyl group. General formula (II): ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) In formula (II), m is an integer from 0 to 8. General formula (III): R^2-CH=CH-CHO...(III) In formula (III), R^2 is a hydrogen atom and has 1 to 5 carbon atoms.
is an alkyl group or a phenyl group. General formula (IV): ▲There are numerical formulas, chemical formulas, tables, etc.▼... (IV) In formula (IV), R^3 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a methoxy group. General formula (V): ▲There are mathematical formulas, chemical formulas, tables, etc.▼…(V) (2) The epoxy resin composition for semiconductor encapsulation according to claim 1, which contains a plasticizer.