JPH0597974A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition, having a low elastic modulus, linear expansion coefficient and moisture absorptivity, excellent in heat and solder crack resistance and useful for sealing IC by blending an epoxy resin with a specific phenolic resin. CONSTITUTION:An epoxy resin composition is obtained by blending (A) an epoxy resin with (B) a phenolic resin containing >=50wt.% phenolic resin having a structure in which a phenolic compound is cross-linked with a bifunctional aromatic residue expressed by the formula (R is lower alkyl; X1 and X2 are H, halogen or lower alkyl) so as to provide 0.5-1.5mol hydroxyl groups in the component (B) based on 1mol epoxy groups in the component (A).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an epoxy resin composition. More specifically, it relates to an epoxy resin composition having a low elastic modulus, a low coefficient of linear expansion and a low water absorption, and excellent heat resistance and solder crack resistance.

[0002]

2. Description of the Related Art Conventionally, diodes, transistors, I
As a method of sealing a semiconductor element such as C or LSI, a so-called resin sealing method using an epoxy resin or the like is widely used. In particular, a resin composition containing an epoxy resin or a novolac type phenol resin as a main component is inexpensive as a raw material,
Due to its excellent heat resistance, moldability, and electrical characteristics, it has become the mainstream of resin encapsulation methods.

By the way, the recent progress in semiconductor element-related technology is extremely fast and diversified, and the conventional epoxy resin or novolac type phenol resin-based resin composition is used as a sealing material. There are various problems that cannot be solved by the method.

[0004] For example, the chip size is increased with the high integration of ICs, and conversely, the package shape tends to be smaller and thinner due to further expansion of surface mounting. That is, it becomes necessary to encapsulate a large chip in a small and thin package, and at this time, thermal stress causes cracks, which is a serious problem.

Further, in the soldering process, the package itself is rapidly exposed to a high temperature of 200 ° C. or more, so that the moisture in the package is rapidly expanded and a crack is generated in the package to improve the reliability of the semiconductor. It is causing the decrease.

Various epoxy resin compositions have been proposed in order to solve these problems, but sufficient effects have not been obtained yet.

For example, JP-A-59-105018 proposes a sealing resin composition using a polycondensation product of phenol and aralkyl ether as a curing agent. However, although this resin composition is excellent in terms of low water absorption and low elastic modulus, it has poor heat resistance due to its low glass transition temperature and is not satisfactory in terms of solder crack resistance.

Further, JP-A-61-168620 proposes an epoxy resin composition having excellent heat resistance. Since the composition uses a polyfunctional epoxy resin, the crosslink density is increased and the heat resistance is excellent. But,
The water absorption is high, and the frequency of cracks is particularly high in the soldering process, which is not satisfactory.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the elastic modulus, linear expansion coefficient and water absorption coefficient are low, and the heat resistance and solder crack resistance are excellent. An object is to provide an epoxy resin composition.

[0010]

SUMMARY OF THE INVENTION The present inventors
The epoxy resin composition comprising a phenolic resin and an epoxy resin obtained by reacting a functional aromatic compound with a phenolic compound and crosslinking the phenolic compound with a bifunctional aromatic nucleus residue has the above-mentioned problems. The present invention has been accomplished by finding that the above is satisfied.

That is, the present invention relates to an epoxy resin (A) and a compound represented by the general formula (1)

[0012]

[Chemical 2] (In the formula, R represents a lower alkyl group, and X ₁ and X ₂ each independently represent a hydrogen atom, a halogen atom, or an alkyl group.)
A resin composition comprising a phenolic resin (B) containing 50% by weight or more of a phenolic resin having a structure in which a phenolic compound is crosslinked with a bifunctional aromatic residue represented by It is an epoxy resin composition in which the hydroxyl group of (B) is 0.5 to 1.5 mol with respect to 1 mol of the epoxy group.

The greatest feature of the epoxy resin composition of the present invention is that it has a low elastic modulus, a linear expansion coefficient and a water absorption coefficient, and also has excellent heat resistance. All of these characteristics are extremely important as an epoxy resin composition for semiconductor encapsulation, and an epoxy resin composition having all of these characteristics has hitherto not been known. This is possible only when a phenolic resin having a specific structure obtained by crosslinking a phenolic compound with a specific bifunctional aromatic nucleus residue is used as a curing agent for an epoxy resin.

The epoxy resin composition of the present invention contains, as essential components, a phenolic resin and an epoxy resin having a structure in which a phenolic compound is crosslinked with a bifunctional aromatic residue represented by the above general formula (1). Although it is an epoxy resin composition, other phenolic resins, curing accelerators, various fillers and the like may be added as long as the object of the present invention is not impaired.

The phenolic resin which is an essential component of the present invention (hereinafter referred to as essential phenolic resin) has the general formula (2)

[0016]

[Chemical 3] (In the formula, each of R ₁ and R ₂ independently represents a hydroxyl group, a halogen atom or a lower alkoxy group having 1 to 3 carbon atoms, and in particular, R ₁ and R ₂ jointly represent one oxygen atom. Good.
R ₃ is a lower alkyl group, and X ₁ and X ₂ are each independently a hydrogen atom, a halogen atom, or an alkyl group. A polyfunctional condensation reaction (crosslinking reaction) of a bifunctional aromatic compound and a phenolic compound ) Is obtained.

Examples of the bifunctional aromatic compound represented by the above general formula (2) include α, α-dichloroxylene,
Examples include α, α-dihaloxylene such as α, α-dibromoxylene, α, α-dialkoxyxylene such as α, α-dimethoxyxylene, α, α-diethoxyxylene, methylbenzaldehyde, ethylbenzaldehyde and propylbenzaldehyde. Be done. Those in which the halogen atom is substituted in the aromatic nucleus of these compounds can also be used.

Further, as the above-mentioned phenolic compound,
Phenol, o-cresol, m-cresol, p-cresol, 2,6-xylenol, 4-methylcatechol, catechol, resorcin, 2,2-bis (p-hydroxyphenyl) propane, bis (p-hydroxyphenyl) methane , P-ethylphenol, pt-butylphenol, pt-octylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, p-aminophenol, pyrogallol, phloroglucinol, α-naphthol, β-. Examples thereof include naphthol, phenanthrol, oxyanthracene and the like. Further, even if a halogen atom is substituted in the aromatic nucleus of these compounds, they can be used in the present invention.

The number average molecular weight of the essential phenolic resin used in the present invention is preferably 350 to 2000 for the purpose of the present invention.

In the present invention, as a curing agent for an epoxy resin (hereinafter referred to as a curing agent resin), in addition to the above essential phenolic resin, a novolac resin of the above-mentioned phenolic compound, a phenol aralkyl resin, a dicyclopentadiene modified phenolic resin. Alternatively, a resol-based phenol resin or the like can be used in combination. The amount of these resins that may be used in combination is preferably less than 50% by weight of the curing agent resin used in the epoxy resin composition of the present invention, that is, less than the essential phenolic resin. When the combined resin content is 50% by weight or more, the above-mentioned characteristics which are the greatest feature of the epoxy resin composition of the present invention, namely, the elastic modulus,
It is not preferable because the characteristics that the coefficient of linear expansion and the water absorption are low and the heat resistance is excellent cannot be maintained.

As the epoxy resin used in the present invention, novolac resin of the above-mentioned phenolic compound, phenol aralkyl resin, dicyclopentadiene modified phenol resin, glycidyl ether such as resole phenolic resin, butanediol, polyethylene glycol, polypropylene glycol. Glycidyl ether of alcohols such as phthalic acid, isophthalic acid, terephthalic acid, glycidyl ester of carboxylic acid such as tetrahydrophthalic acid, aniline, isocyanuric acid and the like, substituted with active hydrogen bonded to the nitrogen atom with a glycidyl group, Examples thereof include alicyclic epoxy resins obtained by epoxidizing an intramolecular olefin.

In the present invention, these epoxy resins preferably have a softening point of 60 to 100 ° C. and an epoxy equivalent of 100 to 400, more preferably a softening point of 65 to 90.
C., the epoxy equivalent is in the range of 150 to 300. These epoxy resins may be used alone, but may be a mixture of two or more kinds.

When the softening point or epoxy equivalent of the epoxy resin is out of the above range, it is not preferable because the above characteristics which are characteristic of the epoxy resin composition of the present invention cannot be maintained.

The mixing ratio of the epoxy resin and the curing agent resin is preferably in the range of 0.5 to 1.5 moles of the hydroxyl group of the curing agent resin to 1 mole of the epoxy group of the epoxy resin.
If it is out of this range, the above-mentioned characteristics which are the characteristics of the epoxy resin composition of the present invention cannot be maintained, which is not preferable.

In the epoxy resin composition of the present invention, a compound that accelerates the reaction between the epoxy group of the epoxy resin and the hydroxyl group of the curing agent resin can be used as a curing accelerator.

Examples of the curing accelerator include amines such as triethylamine, benzyldimethylamine, triethanolamine, tris (dimethylaminomethyl) phenol, triethylamine, triethylenetetramine, metaxylenediamine and dimethylbenzylamine;
Methylimidazole, 2-ethylimidazole, 1,2
-Imidazoles such as methyl imidazole, 2-ethyl-4-methyl imidazole, 2-undecyl imidazole, 2 phenyl imidazole, triphenylphosphine, tributylphosphine, tricyclohexylphosphine, methyldiphenylphosphine, butylphenylphosphine, diphenylphosphine, phenyl Organic phosphines such as phosphine, octylphosphine, 1,2-bis (diphenylphosphino) methane, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-
Examples thereof include tetraphenylboron salts such as methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate.

The addition amount is 0.00 relative to the epoxy resin.
1% to 5% by weight is preferred. Addition amount is 0.001
If it is less than 5% by weight, the reaction between the epoxy groups of the epoxy resin and the hydroxyl groups of the curing agent resin takes too long, which is not preferable. On the other hand, if it exceeds 5% by weight, the above-mentioned characteristics which are characteristic of the epoxy resin composition of the present invention cannot be maintained, which is not preferable.

Further, in the present invention, as the inorganic filler, crystalline silica, fused silica, alumina, clay, titanium white, zircon, boron, beryllia, magnesia, zirconia, forsterite, steatite, spinel,
One or more kinds of mullite, titania, barium sulfate, quartz glass, aluminum hydroxide, potassium titanate, silicon carbide, silicon nitride, alumina, glass fiber and the like can be blended.

Further, in the present invention, higher fatty acids, higher fatty acid metal salts, esters, natural waxes, synthetic waxes, acid amides, mold releasing agents such as paraffin, bromine compounds, antimony, phosphorus are added, if necessary. Flame retardant such as carbon black, colorant such as carbon black, silane coupling agent such as epoxysilane, aminosilane, vinylsilane, alkylsilane, organic titanate, and other additives such as flexibility-imparting agent Good.

As a general method for producing the epoxy resin composition of the present invention using the above-mentioned raw materials, the raw material mixture of a predetermined amount is thoroughly mixed by a mixer or the like, and then kneaded by a hot roll, an extruder or the like. Then, a method of cooling and pulverizing can be mentioned.

As a method of encapsulating a semiconductor using the epoxy resin composition of the present invention, a low-pressure transfer molding method is generally used, but an injection molding method, a compression molding method, a casting method, or the like is adopted. You can also

The epoxy resin composition of the present invention obtained as described above has a low elastic modulus, a low coefficient of linear expansion and a low water absorption rate and excellent heat resistance. It can be used as a laminated material or an adhesive.

[0033]

EXAMPLES The present invention will be described in more detail with reference to production examples, examples, comparative examples and test examples.

Production Example 1 In a reaction vessel equipped with a stirrer, a thermometer, a partial condenser, and a total condenser,
50 g of p-methylbenzaldehyde having a purity of 99.9%
(0.42 mol), 98.8 g of phenol (1.05 mol) and 0.05 g of diethyl sulfate were charged, and the cross-linking reaction was carried out with stirring while maintaining the mixed solution at about 140 ° C.
Water generated during the reaction was removed from the system through the vent port. After reacting for about 2 hours, unreacted phenol was removed by distillation under reduced pressure, and the resinous product remaining in the reactor was cooled.

The obtained reaction product was a reddish brown solid and was further pulverized in a dry atmosphere to obtain a pale red fine powdery essential phenolic resin. The softening point of this resin (according to JIS K-2548) was 103 ° C. This resin is called resin A.

Production Example 2 In a reaction vessel equipped with a stirrer, a thermometer, a partial condenser, and a total condenser,
50 g of a xylene chlorinated mixture containing α, α-dichloro-p-xylene (purity 87.5% by weight) (0.29 mol in total amount of aromatic nuclei), 54.6 g of phenol (0.58)
Mol) and 0.07 g of diethyl sulfate were charged, and the crosslinking reaction was carried out under stirring while maintaining the temperature of the mixture at about 140 ° C. Hydrochloric acid generated during the reaction was removed from the system through the vent port. After stirring for about 2 hours, unreacted phenol was removed by vacuum distillation, and the resinous product remaining in the reaction vessel was cooled. The obtained reaction product was a reddish brown solid. This was pulverized in a dry atmosphere to obtain a pale red fine powdery essential phenolic resin. Softening point of this resin (JIS K
(According to -2548) was 110 ° C. This resin is called resin B.

Example 1 Orthocresol novolac type epoxy resin having an epoxy equivalent of 214 and a softening point of 75 ° C. (manufactured by Nippon Kayaku Co., Ltd., trade name: EOCN102S), Resin A produced in Production Example 1,
Triphenylphosphine (hereinafter TP) as a curing accelerator
P), fused silica as a filler, carnauba wax as a release agent, carbon black as a colorant, and glycidoxypropyltrimethoxysilane as a coupling agent at a weight ratio shown in [Table 1] and kneaded. Temperature 10
Roll kneading was performed under conditions of 0 ° C. to 110 ° C. and kneading time of 5 minutes. The sheet-shaped kneaded product was cooled and then pulverized to obtain an epoxy resin composition.

Next, the composition was added to 200 kg / cm ² , 1
A molded product having a predetermined shape was produced by compression molding at 70 ° C. for 5 minutes, and post-cured at 175 ° C. for 5 hours. The glass transition temperature, linear expansion coefficient, flexural modulus, and water absorption of the obtained molded product were evaluated.

Glass transition temperature (unit: ° C.): From the temperature-linear expansion curve of the molded product using a TMA apparatus manufactured by Rigaku Denki, the temperature at the bending point was taken as the glass transition temperature. The temperature was measured from room temperature to 250 ° C., and the temperature rising rate was 2 ° C./min.

Linear expansion coefficient (unit: × 10 ^-5 / ° C); values from room temperature to glass transition temperature were determined.

Flexural modulus (unit: kg / mm ² ); 4 mm × 127 mm × 1 using Shimadzu autograph
Molded product of 0 mm, test speed 2 mm / min, distance between fulcrums 6
It was performed at 4 mm.

Water absorption rate (unit:%); 50 mm × 50 mm
It was determined from the change in weight after boiling a molded product of × 2 mm at 100 ° C. for 24 hours. The obtained results are shown in [Table 1].

Examples 2 to 5 and Comparative Examples 1 to 2 Using the raw materials shown in [Table 1], molded articles were obtained in the same manner as in Example 1, and the respective properties were evaluated in the same manner. The obtained results are shown in [Table 1].

[0044]

[Table 1]

Test Example The epoxy resin compositions produced in Examples 1 to 4 and Comparative Examples 1 to 2 were tableted and subjected to low pressure transfer molding,
Under conditions of 175 ° C., 70 kg / cm ² and 120 seconds, a 6 × 6 mm chip for a solder crack test is sealed in a 52p package, and a solder moisture resistance test is 3 mm × 6.
The mm chip was encapsulated in a 16p SOP package. The following solder crack test and solder moisture resistance test were performed on the sealed test element.

Solder crack test: The sealed test element was left in an environment of 85 ° C. and 85% RH for 72 hours, then immersed in a solder bath of 260 ° C. for 10 seconds, and then external cracks were observed with a microscope. The number of cracked elements was counted.

Solder moisture resistance test; 8 sealed test elements
Leave for 72 hours in an environment of 5 ° C and 85% RH, then 2
After soaking in a solder bath at 60 ° C. for 10 seconds, a pressure cooker test (125 ° C., 100% RH) was performed to measure the time at which the circuit open defect rate was 50%. The test results are shown in [Table 2].

[0048]

[Table 2]

[0049]

The epoxy resin composition of the present invention has a low elastic modulus, a linear expansion coefficient and a water absorption coefficient, and also has excellent heat resistance. Furthermore, since it has excellent solder crack resistance and solder moisture resistance, it can be used as a semiconductor sealing material. Further, by utilizing the above characteristics, it can be used in a wide range of fields such as for paints, for lamination and for adhesives,
It is extremely useful in industry.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // C08G 8/04 NBU 8215-4J

Claims (1)

[Claims] 1. An epoxy resin (A) and a compound represented by the general formula (1): [Chemical Formula 1] (Wherein R represents a lower alkyl group, and X ₁ and X ₂ independently represent a hydrogen atom, a halogen atom or a lower alkyl group), and the phenolic compound is crosslinked with a bifunctional aromatic residue. 50 phenolic resin having the structure
A resin composition comprising a phenolic resin (B) contained in an amount of not less than wt%, wherein 1 mol of the epoxy group of (A):
An epoxy resin composition in which the hydroxyl group of (B) is 0.5 to 1.5 mol.