JP2003268073A - Curing agent for epoxy resin, its composition and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a new epoxy resin curing agent which constitutes an epoxy resin composition useful for a molding material, various kinds of binders, a coating material, a laminating material, etc., having low water absorption properties, a low modulus of elasticity and a low melt viscosity and, especially when used as a semiconductor sealing material, having excellent solder heat resistance and curability. <P>SOLUTION: The epoxy curing agent comprises a thioester compound containing two or more RSC(O)- groups such as an RSC(O)PhC(O)SR (R is a hydrocarbon group; Ph is a phenylene group). The composition comprises the curing agent and an epoxy resin. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel epoxy resin curing agent comprising a polythioester compound. More specifically, it relates to an epoxy resin composition useful as a molding material, various binders, coating materials, laminates, etc. containing such a curing agent. In particular, when used as a curing agent in an epoxy resin-based semiconductor encapsulant, a polythioester-based epoxy resin curing agent that has low water absorption, low elastic modulus, low melt viscosity, and excellent molding curability The present invention relates to an epoxy resin composition containing a resin.

[0002]

2. Description of the Related Art As curing agents for epoxy resins, amines, acid anhydrides, polyamides, imidazoles, polyphenols, polymercaptans and the like have been known so far. In addition, a cationic or anionic catalyst-based curing agent and a special curing agent having heat or light latency are also known. Among them, regarding polymercaptans,
When a tertiary amine is also used as a curing accelerator, it can be cured at a low temperature and at high speed, and has been put to practical use as a curing agent having a relatively long pot life. All of these are compounds having a plurality of mercaptan groups (-SH groups), and aliphatic ethers, aliphatic esters, aliphatic polysulfides, and the like are known, but they have a big problem of giving offensive odor.

On the other hand, as a resin composition used for semiconductor encapsulation, it is general to use a compound having a phenolic hydroxyl group as a curing agent together with an epoxy resin such as an orthocresol novolac type epoxy resin.
However, acid anhydrides and amine-based curing agents are used as curing agents for optical semiconductors and liquid encapsulation. In any case, no mercaptan type curing agent is used. If a conventionally known polymercaptan-based curing agent for semiconductor encapsulation is used, in addition to a bad odor, viscosity increases and fluidity decreases with time, reacts even at low temperatures and has low thermal potential.
Various defects such as poor water absorption and easy burning are expected.

In recent years, however, the required performance of the encapsulant has changed significantly due to the rise in the mounting temperature due to the lead-free solder, the large size of the LSI chip, the thinning / miniaturization of the package, and the diversification of the package shape. Therefore, it has become difficult for conventional epoxy resin encapsulation materials to sufficiently cope with such points as moisture resistance, heat resistance, and reliability. For example, during heat treatment during soldering, cracking or peeling of the package due to rapid vaporization and expansion of moisture absorption becomes a problem. On the other hand, from the viewpoint of improving productivity, there is a demand for a curing agent having excellent fluidity, rapid curability, and short molding cycle.

In order to further improve the solder heat resistance, it is desired to develop an epoxy resin and a curing agent that have low water absorption and low elastic modulus at the soldering temperature. There is also a demand for improved adhesion to LSI components. In response to such a demand, a phenol aralkyl resin as a curing agent (Japanese Patent Publication No. 47-13782, Japanese Patent Publication No. 47-15111).
No.) is used. Phenol aralkyl resin is obtained by reacting a phenol compound with an aromatic compound having two halomethyl groups, alkoxymethyl groups, hydroxymethyl groups, etc., and has the effect of lowering the OH group concentration, resulting in low water absorption and heat. It aims to lower the elasticity, and some effects are recognized,
It wasn't enough.

Recently, a phenol biphenyl aralkyl resin of a type in which an aromatic compound having two or more alkoxymethyl groups is reacted with bis (methoxymethylbiphenyl) has been proposed (Japanese Patent No. 3122834 etc.),
Although it has been improved to some extent, it cannot be said to be sufficiently satisfactory in this case as well. Especially for lead-free solder,
In the situation where an increase in soldering temperature is unavoidable, a material having a further lower water absorption and a lower elastic modulus is required. Also,
Such a material having a high hydroxyl equivalent has a drawback that it causes a decrease in the curability and prolongs the molding cycle, clogs the gate, has a poor mold release, and causes a significant loss in productivity such as stacking.

In addition to this, the use of polycyclic aromatic compounds such as naphthol has been proposed (Japanese Patent Laid-Open No. 9-1762).
No. 62), it is essential to use an excessive amount of phenol for the purpose of increasing the melt viscosity, and a sufficient improvement has not necessarily been obtained.

Further, naphthol aralkyl resin and petroleum pitch copolymerized with formaldehyde together with phenol, addition reaction products of divinylbenzene and phenol, addition reaction products of dicyclopentadiene and phenol, etc. have been proposed, and some of them have been adopted. However, it has not reached the target characteristics.

[0009] These conventional improved prescriptions mainly reduce the concentration of alcoholic hydroxyl groups produced by the reaction between the epoxy resin and the phenolic curing agent, and thus reduce the phenolic hydroxyl groups of the curing agent and the epoxy groups of the epoxy resin. there were. Therefore, although it was effective in lowering the water absorption and reducing the elastic modulus in the soldering temperature range, the curing time at the time of encapsulation became longer due to the decrease in the number of functional groups (crosslinking points), and the separation from the mold was performed. Productivity was sometimes impaired due to mold defects. Further, even with such a formulation, although the alcoholic hydroxyl group is reduced, it is still generated, so that the lowering of the water absorption is essentially limited.

As a prescription for reducing the formation of alcoholic hydroxyl groups, those in which a phenolic hydroxyl group in a curing agent is esterified have recently been proposed. However, due to its poor reactivity with epoxy groups, partial esterification may occur. (JP-A-7
-53675, JP-A-8-208807, JP-A-1
0-168283), using a special curing catalyst (JP-A-2000-53748, JP-A-2000-14377).
No. 5) has been reported. However, because of the large decrease in curability compared to phenolic hydroxyl groups,
The current situation is that there are still many issues for practical application.
Further, in the case of partially esterified in consideration of the balance with curability, the esterification rate decreases and the effect of reducing the water absorption rate becomes small.

[0011]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to significantly reduce water absorption to a level which cannot be reached by conventional phenol resin type curing agents in an epoxy resin curing system for semiconductor encapsulation and to cure the same. It is intended to provide a novel epoxy resin curing agent that provides a cured product having excellent properties, a low viscosity, and a low elastic modulus when heated. Another object of the present invention is to provide a curable composition containing such an epoxy resin curing agent in an epoxy resin and a cured product thereof.

[0012]

That is, the present invention is based on the general formula (1)

[Chemical 7] (In the formula, R is a hydrocarbon group) The present invention relates to an epoxy resin curing agent composed of a thioester compound having two or more thioester groups.

The present invention also relates to an epoxy resin composition comprising the above thioester compound and an epoxy resin, and further an epoxy resin cured product obtained by curing the same.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the thioester group represented by the general formula (1) of the thioester compound used in the present invention, R is a hydrocarbon group and may contain a heteroatom such as halogen and oxygen. Well, for example, a substituted or unsubstituted alkyl group such as methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl, tert-butyl, 2-ethylhexyl, cyclohexyl, benzyl, 2-chloroethyl, and 2-ethoxyethyl, Phenyl,
2- or 3- or 4-methylphenyl, 2- or 3- or 4-ethylphenyl, 2- or 3- or 4-isopropylphenyl, 2- or 3- or 4-isobutylphenyl, 2- or 3-or 4-tert-butylphenyl,
2- or 3- or 4-benzylphenyl, 2- or 3-
Or, a substituted or unsubstituted aryl group such as 4-chlorophenyl, 2- or 3- or 4-ethoxyethylphenyl, 2- or 3- or 4-phenylphenyl, α- or β-naphthyl can be mentioned. By changing the type of R, the curing speed with the epoxy resin can be adjusted to a desired value. Generally, when R is an aryl group,
It is preferable because the curing rate with the epoxy resin is moderate, but it is of course possible to use one in which R is an alkyl group, which has a high curing rate, and it may be appropriately selected according to the purpose.

Specific examples of the thioester compound include those represented by the general formula (2) or (3)

[Chemical 8]

[Chemical 9] (In the formula, R is a hydrocarbon group, R ¹ and R ² are each hydrogen or a hydrocarbon group, and n is 2 or 3). R is a hydrocarbon group similar to R in the general formula (1), R ¹ and R ² are each hydrogen or a hydrocarbon group, and when a hydrocarbon group, it is the same as R.

Another specific example of the thioester compound having two or more thioester groups represented by the general formula (1) is represented by the general formula (4).

[Chemical 10] (In the formula, Ar ¹ and Ar ² are each represented by the following general formula (5).
Is a phenylene group represented by or a naphthalene group represented by the general formula (6), X is a direct bond, a divalent hydrocarbon group, O, S or SO ₂ , and R ³ and R ⁴ are hydrocarbons. Group, and n is an integer of 1 or more).

[Chemical 11]

[Chemical 12] (In the formula, R ⁵ , R ⁶ , and R ⁷ are each hydrogen, a hydrocarbon group, an R ⁸ SC (O) group (R ⁸ is a hydrocarbon group) or halogen, and s, t, and u are 1 or 2 respectively. Integer)

A thioester compound represented by the general formula (4)
In the thing, R^ThreeAnd R^FourIs a hydrocarbon group,
It may contain heteroatoms such as elemental, sulfur and halogen
The examples of R in the general formula (1) are
Can be mentioned. Also Ar ¹And Ar^TwoIs the general formula
Which is represented by (5) or (6),
R in⁵, R⁶And R⁷Are hydrogen and hydrocarbon, respectively
Groups such as methyl, ethyl, isopropyl, n-propyi
, Isobutyl, n-butyl, tert-butyl, 2-
Ethylhexyl, cyclohexyl, benzyl, 2-chloro
Substituted or unsubstituted such as ruethyl and 2-ethoxyethyl
Alkyl group, phenyl, 2- or 3- or 4-methyl group
Phenyl, 2- or 3- or 4-ethylphenyl, 2-or
Is 3- or 4-isopropylphenyl, 2- or 3- or
Is 4-isobutylphenyl, 2- or 3- or 4-te
rt-butylphenyl, 2- or 3- or 4-benzyl
Phenyl, 2- or 3- or 4-chlorophenyl, 2-
Or 3- or 4-ethoxyethylphenyl, 2- or 3
-Or 4-phenylphenyl, 2-or 3- or 4-me
Tylsulfinylphenyl, α- or β-naphthyl, R
⁹SC (O) group (R⁹Is a hydrocarbon group, and as R mentioned above
As exemplified) substituted aryl group as described above
Any substituted or unsubstituted aryl group, C₆H₅SC
(O), C₁₀H₇R such as SC (O)⁸With SC (O)
With the groups represented, halogens such as fluorine, chlorine, bromine, iodine
is there. Here, s, t, and u are integers of 1 and 2, respectively.
, S R⁵, T R⁶And u R⁷Is that
These may be the same or different.

X in the general formula (4) is a direct bond, 2
Is a valent hydrocarbon group, O, S or SO ₂ , and n is an integer of 1 or more, usually 10 or less, preferably 1 to 3. When X is a divalent hydrocarbon group, it may contain a different element such as oxygen, sulfur and halogen, for example, -Ar ^3-.
C (O) -S-R ¹⁰ (wherein Ar ³ is a substituted or unsubstituted aryl group, R ¹⁰ is a substituted or unsubstituted alkyl group or aryl group, for example, phenylene, naphthalene, substituted phenylene, substituted naphthalene, etc. R), such as those exemplified as R). Here, n pieces of X, n pieces of Ar ² , and n pieces of R ⁴ may be the same or different. The epoxy resin curing agent of the present invention may of course be a mixture of two or more different compounds represented by the general formula (4),
In that case, it is preferable that the average value of n is 1 to 3.

When X in the above formula is a hydrocarbon group, the following can be specifically exemplified. For example, in addition to alkylene groups such as methylene, ethylene, trimethylene, isopropylidene, tetramethylene, isobutylidene, cyclohexylene, and arylene groups such as phenylene and methylphenylene, the following (7) to (2
Examples such as 3) can be exemplified.

[0020]

[Chemical 13]

[Chemical 14]

[Chemical 15]

[Chemical 16]

[Chemical 17]

[Chemical 18]

[Chemical 19]

[0021]

[Chemical 20]

[Chemical 21]

[Chemical formula 22]

[Chemical formula 23]

[Chemical formula 24]

[Chemical 25]

As a crystalline curing agent having a low viscosity, n is 2 in the general formula (2) or (3),
A compound in which R is an aryl group or an alkyl group having 1 to 18 carbon atoms is preferable. Specific examples of such compounds include compounds represented by formulas (24) to (29).

[0023]

[Chemical formula 26]

[Chemical 27]

[Chemical 28]

[Chemical 29]

[Chemical 30]

[Chemical 31]

As another example of the crystalline curing agent having low viscosity, in the general formula (4), Ar ¹ and Ar ² are phenylene, n is 1, X is a direct bond, O,
A compound represented by the general formula (30), which is S, SO ₂ , CH ₂ or C (CH ₃ ) ₂ and R ³ and R ⁴ are an aryl group or an alkyl group having 1 to 18 carbon atoms, is preferable.

[Chemical 32]

Specific examples of such a compound include compounds represented by the formulas (31) to (46).

[Chemical 33]

[Chemical 34]

[Chemical 35]

[Chemical 36]

[0026]

[Chemical 37]

[Chemical 38]

[Chemical Formula 39]

[Chemical 40]

[0027]

[Chemical 41]

[Chemical 42]

[Chemical 43]

[Chemical 44]

[0028]

[Chemical formula 45]

[Chemical formula 46]

[Chemical 47]

[Chemical 48]

The thioester group represented by the general formula (1) is
A compound having two or more compounds has one SH group.
Compound, carboxyl group, carboxylic acid ester group,
Compounds and phthalates having two or more boric acid halide groups
By reacting with an acid anhydride such as an acid anhydride
Obtainable. For example, in the general formula (2), R ¹
Is hydrogen and n is 2, the thioester compound is
When using rubonic acid chloride as the raw material, use (47) below.
It can be produced by the reaction formula shown.

[0030]

[Chemical 49]

In the above reaction, the solvent is preferably a basic solvent that traps hydrogen chloride generated by the reaction, such as pyridine. In that case, the reaction may be carried out in the presence of a base such as potassium bicarbonate or sodium hydroxide.

When the raw material is a dicarboxylic acid, a suitable dehydrating condensing agent such as dicyclohexylcarbodiimide can be used in order to accelerate the reaction and remove the produced water as much as possible. As the solvent, a general polar solvent such as dimethylformamide, dimethylsulfoxide and methylpyrrolidone can be used. In the case of dicarboxylic acid,
The reaction proceeds without adding a catalyst by its own catalytic action, but a protonic acid, an organometallic compound such as titanium, tin, or lead, or an oxide or salt of a heavy metal can also be used as a catalyst.

The reaction temperature varies depending on the starting materials used, but when a dicarboxylic acid halide is used, the reaction temperature is preferably in the range of 0 to 200 ° C, preferably 20 to 150 ° C. After completion of the reaction, the desired thioester compound can be obtained by performing general purification operations such as washing and recrystallization.

The thioester compound thus obtained is
It is useful as an epoxy resin curing agent, and when used as a curing agent in an epoxy resin-based semiconductor encapsulant, a fast-curing epoxy resin composition having low water absorption, low elastic modulus and low melt viscosity can be obtained.

Examples of the epoxy resin which can be used together with the thioester compound of the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, Phenol biphenyl aralkyl type epoxy resin, epoxide of aralkyl resin by xylylene bond such as phenol and naphthol, dicyclopentadiene type epoxy resin, glycidyl ether type epoxy resin such as dihydroxynaphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type Epoxy resins having two or more epoxy groups in the molecule, such as epoxy resins and halogenated epoxy resins, can be mentioned.
These epoxy resins may be used alone or in combination of two or more.

Upon curing the epoxy resin, it is desirable to use a curing accelerator together. As such a curing accelerator, a known curing accelerator for curing an epoxy resin with a phenol resin-based curing agent can be used. For example, a tertiary amine, a quaternary ammonium salt, an imidazole and its tetraphenylboron salt, An organic phosphine compound and its boron salt, a quaternary phosphonium salt, etc. can be mentioned. More specifically, triethylamine, triethylenediamine, benzyldimethylamine, 2,4
6-tris (dimethylaminomethyl) phenol, 1,
Tertiary amines such as 8-diazabicyclo (5,4,0) undecene-7, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4- Imidazoles such as methylimidazole, organic phosphine compounds such as triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetranaphthoic acid borate, etc. Can be mentioned. Particularly useful are tertiary amines, quaternary ammonium salts and imidazoles.

If necessary, an inorganic filler, a coupling agent, a release agent, a colorant, a flame retardant, a flame retardant aid, a low stress agent, etc. are added to the epoxy resin composition of the present invention or previously added. It can be used by reacting. A phenolic polymer curing agent can also be used in combination. In this case, the thioester compound curing agent of the present invention is effective in lowering the melt viscosity, lowering the water absorption, lowering the elastic modulus, and rapidly curing the phenolic polymer curing agent. Such a phenol resin type curing agent is a compound having two or more phenolic hydroxyl groups in one molecule, and examples thereof include phenol novolac resin, cresol novolac resin, and Japanese Patent Publication No. 47-1378.
No. 2, JP-B-47-15111, JP-A-6-1842.
58, JP-A-6-136082, JP-A-7-258.
Phenol aralkyl resin, phenol biphenyl aralkyl resin, phenol naphthyl aralkyl resin, naphthol aralkyl resin, triphenol methane type novolak resin and the like disclosed in Japanese Patent No. 364, No. 3122834 and the like can be exemplified.

Especially when used for semiconductor encapsulation, the addition of an inorganic filler is essential. Examples of such inorganic fillers include amorphous silica, crystalline silica, alumina, glass, calcium silicate, gypsum, calcium carbonate, magnesite, clay, talc, mica, magnesia, barium sulfate and the like. However, amorphous silica and crystalline silica are particularly preferable. Further, in order to increase the compounding amount of the filler while maintaining excellent moldability, it is preferable to use a spherical filler having a wide particle size distribution that enables fine packing.

Examples of coupling agents include vinylsilane-based, aminosilane-based, epoxysilane-based, and other silane-based coupling agents and titanium-based coupling agents, and release agents include carnauba wax, paraffin wax, and the like.
Stearic acid, montanic acid, a carboxyl group-containing polyolefin wax and the like, and examples of the colorant include carbon black and the like. Examples of flame retardants include halogenated epoxy resins, halogen compounds, phosphorus compounds and the like, and flame retardant aids such as antimony trioxide. Examples of the stress reducing agent include silicone rubber, modified nitrile rubber, modified butadiene rubber,
Examples include modified silicone oil.

The compounding ratio of the thioester compound of the present invention to the epoxy resin is, considering heat resistance and mechanical properties,
The equivalent ratio of thioester group / epoxy group is 0.5 to 1.
5, particularly preferably in the range of 0.8 to 1.2. The tertiary amine, which is suitable as a curing accelerator, is preferably used in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin in consideration of curing characteristics and various physical properties.
Furthermore, in the epoxy resin composition for semiconductor encapsulation,
Although slightly different depending on the type of the inorganic filler, considering the solder heat resistance, moldability (melt viscosity, fluidity), low stress property, low water absorption, etc., the inorganic filler is used in an amount of 60-9.
It is preferable to mix them in such a proportion that they account for 3% by weight.

As a general method for preparing an epoxy resin as a molding material, a predetermined proportion of each raw material is thoroughly mixed by, for example, a mixer, then kneaded by a hot roll or a kneader, and then cooled and solidified. A method such as crushing into an appropriate size can be mentioned.
The molding material thus obtained is obtained by sealing a semiconductor element by, for example, low-pressure transfer molding,
A semiconductor device can be manufactured. Curing of the epoxy resin composition can be performed, for example, in a temperature range of 100 to 250 ° C.

[0042]

The present invention will be described in more detail with reference to the following examples. [Reference Example 1] 20.3 g of terephthalic acid dichloride
(0.1 mol) and 60.9 g of pyridine were added to a solution of 24.2 g (0.22 mol) of thiophenol.
Sequentially added over a period of minutes, the temperature was raised to 85 ° C., and then the reaction was performed for 2 hours. Unreacted terephthalic acid dichloride was not detected in the reaction solution. After 100 ml of methyl isobutyl ketone and 100 ml of pure water were added to the reaction solution, the precipitated crystals were separated by filtration. Then, the obtained crystals are treated with pure water 100
It was washed with ml three times and dried under reduced pressure for 10 hours to give di (S-
Phenyl) dithioterephthalate 28.9 g (82.6)
% Yield).

Reference Example 2 The same as Reference Example 1 except that 20.3 g (0.1 mol) of isophthalic acid dichloride was used in place of 20.3 g (0.1 mol) of terephthalic acid dichloride. And the reaction is carried out at a melting point of 12
1 ° C di (S-phenyl) dithioisophthalate 25.
7 g (73.3% yield) was obtained.

Reference Example 3 The same procedure as in Reference Example 1 was repeated except that a solution containing 27.9 g (0.1 mol) of biphenyl-4,4'-dicarboxylic acid dichloride and 83.7 g of pyridine was used. By reacting with phenol, 4,4'-di (S- having the melting point of 235 ° C represented by the above formula (33) is obtained.
Phenyl) biphenyldithiocarboxylate 35.4
g (83.7% yield) was obtained.

Example 1 Di (S-phenyl) dithioterephthalate represented by the formula (26) obtained in Reference Example 1, epoxy resin (ESCN-195X manufactured by Sumitomo Chemical Co., Ltd.)
L, orthocresol novolac type, epoxy equivalent 19
5 g / eq), fused silica, 1,8-diazabicyclo (5,4,0) undecene-7 (DBU), an aminosilane coupling agent and carnauba wax were mixed in the proportions shown in Table 1 and thoroughly mixed, An epoxy resin composition was obtained by kneading with a two-roll roll at 85 ° C. ± 3 ° C. for 3 minutes, cooling and pulverizing. Curatometer curability was measured using this.

Further, the epoxy resin composition was molded by a transfer molding machine at a pressure of 100 kgf / cm ² at 175 ° C. for 2 minutes and then post-cured at 180 ° C. for 6 hours to obtain water absorption, bending elastic modulus and glass transition temperature ( A test piece for Tg) was obtained.

The characteristics of these epoxy resin compositions and cured epoxy resins were measured by the following methods.

(1) Water Absorption Rate The water absorption rate was measured when a disk having a 50 mm diameter × 3 mm sample shape was made to absorb water for 168 hours in an atmosphere of 85 ° C. and a relative humidity of 85% RH. Water absorption rate (%) = (weight increase after treatment / weight before treatment)
× 100

(2) Flexural Modulus Sample shape A strip of 80 × 10 × 4 mm was allowed to stand in an atmosphere of 260 ° C. for 10 minutes, and then measured according to JIS K6911.

(3) Glass transition temperature (Tg) The linear expansion coefficient was measured by TMA, and the inflection point of the linear expansion coefficient was defined as Tg.

(4) Melt Viscosity at 175 ° C. 1 g of an epoxy resin composition was used as a tablet, and a high-lower flow tester (temperature 175 ° C., pressure 10 kgf / cm ² ,
The melt viscosity of the composition was measured with an orifice diameter of 1 mm and a length of 1 mm).

(5) Curastometer About 5 g of the curable epoxy resin composition was used as a tablet, and the change in torque according to the curing was measured with a curast meter at a mold temperature of 175 ° C.

(6) Solder Crack Occurrence Rate The epoxy resin compositions of Examples and Comparative Examples were mounted on a copper frame and were 6.7 mm × 6.7 mm × 0.4 mm.
LSI chip of 175 ℃, 150 seconds, pressure 60kg
sealed by transfer molding under the condition of f / cm ² ,
After post-curing at 175 ° C. for 4 hours, eight 60-pin QFP (package size 20 mm × 14 mm × 2.7 mm) semiconductor devices were formed. This semiconductor device is
After treatment for 168 hours in a thermo-hygrostat at 5 ° C. and 85% humidity, it was immersed in silicone oil at 260 ° C. for 10 seconds, and the occurrence of internal cracks was observed by soft X-ray.

[Examples 2 to 4 and Comparative Example 1] The compounds having the composition shown in Table 1 were evaluated in the same manner as in Example 1.
Incidentally, as the phenol aralkyl resin in the table,
HE100C-15 manufactured by Sumikin Chemical Co., Ltd. (hydroxyl equivalent 170 g / eq) was used.

[0055]

[Table 1] Numerical values of raw materials in the table are parts by weight

[0056]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a thioester compound-based epoxy resin curing agent which is useful for molding materials, various binders, coating materials, laminated materials and the like.
Such a thioester compound has low water absorption, low elastic modulus, high fluidity (low melt viscosity), and excellent solder heat resistance, especially when used as an epoxy resin curing agent for semiconductor encapsulation.
An epoxy resin composition having good curability can be formed.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/31 F term (reference) 4H006 AA01 AA03 AB49 4J002 CD021 CD041 CD051 CD061 CD081 CD121 DE077 DE147 DE237 DG047 DG057 DJ007 DJ017 DJ037 DJ047 DJ057 DL007 EN028 EN108 EU118 EU138 EV016 EV066 EV216 EW018 EY018 FA087 FD017 FD090 FD130 FD146 FD158 FD160 FD200 GJ02 GQ01 4J036 AA01 DA05 DC05 DD01 FA01 JA07 4M109 AA01 BA01 CA21 EB02 EC01 EC03 GA04

Claims (10)

[Claims] 1. A compound represented by the general formula (1): An epoxy resin curing agent comprising a thioester compound having two or more thioester groups represented by the formula (wherein R is a hydrocarbon group). 2. A thioester compound is represented by the general formula (2) or (3): [Chemical 3] (In the formula, R is a hydrocarbon group, R ¹ and R ² are each hydrogen or a hydrocarbon group, and n is 2 or 3.) The epoxy resin curing agent according to claim 1. 3. The thioester compound has the general formula (4): (In the formula, Ar ¹ and Ar ² are each a phenylene group represented by the general formula (5) or a naphthalene group represented by the general formula (6), X is a direct bond, a divalent hydrocarbon group,
The epoxy resin curing agent according to claim 1, which is O, S or SO ₂ , R ³ and R ⁴ are hydrocarbon groups, and n is an integer of 1 or more). [Chemical 5] [Chemical 6] (In the formula, R ⁵ , R ⁶ , and R ⁷ are each hydrogen, a hydrocarbon group, an R ⁸ SC (O) group (R ⁸ is a hydrocarbon group) or halogen, and s, t, and u are 1 or 2 respectively. Integer) 4. The epoxy resin curing agent according to claim 3, which is a thioester compound in which n is 1 in the general formula (4). 5. An epoxy resin composition comprising the thioester compound according to claim 1 and an epoxy resin. 6. The epoxy resin composition according to claim 5, which contains an inorganic filler. 7. The epoxy resin composition according to claim 5, which contains a tertiary amine. 8. The method according to claim 5, which is used for semiconductor encapsulation.
The epoxy resin composition described. 9. An epoxy resin cured product obtained by curing the epoxy resin composition according to claim 5. 10. A semiconductor device obtained by encapsulating a semiconductor element using the epoxy resin composition according to claim 8.