JP2689805B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

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 for semiconductor encapsulation which has excellent moisture resistance after thermal cycle and has low water absorption.

[0002]

2. Description of the Related Art Epoxy resins are excellent in heat resistance, moisture resistance, electrical properties, adhesiveness, etc., and can be imparted with various properties by blending and prescription, so that they are used as industrial materials such as paints, adhesives, and electrical insulating materials. Have been.

For example, as a method for sealing electronic circuit components such as semiconductor devices, a hermetic seal made of metal or ceramic and a phenol resin, silicone resin,
Resin sealing using an epoxy resin or the like has been proposed. However, resin sealing with epoxy resin is mainly used in terms of balance between economy, productivity, and physical properties.

In recent years, the degree of integration of semiconductor devices has remarkably advanced, the element size has increased, and the wiring has become finer. When such a semiconductor element is sealed with an epoxy resin, strain stress occurs due to curing shrinkage during curing, thermal shrinkage during cooling, displacement of aluminum wiring and cutting of bonding wires, and the element and sealing resin itself. There is a problem that reliability is deteriorated due to cracking.

Therefore, a method for reducing the stress of the epoxy resin by blending a silicone rubber, a carboxyl group-modified nitrile rubber, a polystyrene block copolymer or the like as a stress reducing agent (Japanese Patent Publication No. Sho 60-18145, Kaisho 5
8-219218, JP-A-59-96122, JP-A-58-108220, and JP-A-59-7.
5922 and JP-A-60-1220) have been proposed.

Although not directly related to moisture resistance and water absorption after the thermal cycle, 4,4'-dihydroxy-3,
3 ', 5,5'-Tetramethylbiphenyl is being studied (IEEE 1990 Conference Proceedings, p. 625). Here, 4,4'-dihydroxy-3,3 ',
We are studying the solder resistance using 5,5'-tetramethylbiphenyl as a curing agent, but it is completely unknown whether it will be useful for the solder resistance.

[0007]

However, although the method of adding the stress-reducing agent improves the moisture resistance reliability after the thermal cycle, when the amount of the stress-reducing agent increases, the stress reducing agent is added to the surface of the package. There were problems such as bleeding.

Further, 4,4'-dihydroxy-3,3
The method using ′, 5,5′-tetramethylbiphenyl as a curing agent is not practical because of poor reactivity, low glass transition temperature, and poor moisture resistance reliability.

An object of the present invention is to solve these problems and to be suitable for semiconductors which are required to have high integration and high reliability. The epoxy resin composition for semiconductor encapsulation has excellent moisture resistance reliability after thermal cycle and low water absorption. To provide things.

[0010]

Means for Solving the Problems The present inventors have achieved the above-mentioned problems by adding a curing agent having a biphenyl skeleton, and obtain an epoxy resin composition for semiconductor encapsulation which meets the purpose. And has reached the present invention.

That is, the present invention is a semiconductor encapsulating epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a filler (C), wherein the curing agent (B) is Formula (I)

Embedded image An epoxy resin composition for semiconductor encapsulation, comprising the biphenyl compound (b) represented by

The structure of the present invention will be described in detail below.

The epoxy resin (A) according to the present invention comprises 1
It is not particularly limited as long as it has two or more epoxy groups in the molecule, and specific examples thereof include, for example, a cresol novolac type epoxy resin, a bisphenol A type epoxy resin, a linear aliphatic type epoxy resin, Examples thereof include alicyclic epoxy resins, heterocyclic epoxy resins and spiro ring-containing epoxy resins.

In the present invention, the compounding amount of the epoxy resin (A) is usually in the range of 3 to 25, preferably 4 to 20% by weight. If it is less than 3% by weight, moldability and adhesiveness are insufficient. However, if it exceeds 25% by weight, the linear expansion coefficient becomes large and it becomes difficult to reduce the stress, which is not preferable.

It is important that the curing agent (B) in the present invention contains the biphenyl compound (b) represented by the above formula (I) as an essential component.

When the biphenyl compound (b) is not contained, the effect of improving the moisture resistance reliability after the thermal cycle is not exhibited.

The curing agent (B) in the present invention preferably contains a polyfunctional curing agent other than the above biphenyl compound (b) as a crosslinking agent. As a curing agent that can be used in combination,
For example, phenol novolac resin, cresol novolac resin, phenol compound (b ′) represented by the following general formula (II), acid anhydride such as maleic anhydride, phthalic anhydride, pyromellitic anhydride and metaphenylene. Examples thereof include aromatic amines such as diamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0018]

Embedded image (In the formula, R is a hydrogen atom, a C6-7 aryl group or C
It represents an alkyl group of 1 to 4. ).

Among them, phenol novolac resin and phenol compound (b ') are preferable from the viewpoint of moisture resistance reliability.

The proportion of the biphenyl compound (b) contained in the curing agent (B) is not particularly limited, and the effect of the present invention is exhibited if the biphenyl compound (b) is contained as an essential component. In order to exert a sufficient effect, the biphenyl compound (b) is usually added to the curing agent (B) in an amount of 5
.About.90% by weight, preferably 20 to 70% by weight.

The addition amount of the curing agent that can be used in combination is preferably 10 to 95% by weight in the curing agent.

In the present invention, the content of the curing agent (B) is usually 1 to 20% by weight, preferably 2 to 15% by weight. Furthermore, the mixing ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of (B) to (A) is 0.5 to 1.5, especially from the viewpoint of mechanical properties and moisture resistance reliability. 0.
It is preferably in the range of 8 to 1.2.

In the present invention, the epoxy resin (A)
A curing catalyst may be used for accelerating the curing reaction between the curing agent and the curing agent (B). The curing catalyst is not particularly limited as long as it promotes the curing reaction. For example, 2-methylimidazole,
Imidazole compounds such as 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, triethylamine, benzyldimethylamine, α-methylbenzyl Tertiary amine compounds such as dimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7, zirconium tetra Organometallic compounds such as methoxide, zirconium tetrapropoxide, tetrakis (acetylacetonato) zirconium, tri (acetylacetonato) aluminum and triphenylphosphine, trimethylphosphine;
Organic phosphine compounds such as triethylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, and tri (nonylphenyl) phosphine are exemplified. Of these, organic phosphine compounds are preferred from the viewpoint of moisture resistance, and triphenylphosphine is particularly preferably used.

Two or more kinds of these curing catalysts may be used in combination depending on the use, and the addition amount thereof is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin (A).

The filler (C) in the present invention includes amorphous silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass fiber. Among them, fused silica is particularly preferably used because it has a large effect of lowering the linear expansion coefficient and is effective in reducing stress.

The amount of the filler added is 70 to 95, preferably 75 to 90% by weight based on the whole epoxy resin composition.

In the present invention, it is preferable in terms of reliability that the filler is surface-treated in advance with a coupling agent such as a silane coupling agent or a titanate coupling agent. As the coupling agent, a silane coupling agent such as epoxy silane, amino silane, and mercapto silane is preferably used.

The epoxy resin composition of the present invention includes a halogen compound such as a halogenated epoxy resin, a flame retardant such as a phosphorus compound, a flame retardant aid such as antimony trioxide, a colorant such as carbon black and iron oxide, and a silicone rubber. , Olefin copolymers, styrene block copolymers, modified nitrile rubber, modified polybutadiene rubber, modified silicone oil and other elastomers, polyethylene and other thermoplastic resins, long chain fatty acids, long chain fatty acid metal salts, long chain fatty acids An ester, a long-chain fatty acid amide, a releasing agent such as paraffin wax, and a crosslinking agent such as an organic peroxide can be optionally added. The epoxy resin composition of the present invention is preferably melt-kneaded, for example, manufactured by melt-kneading using a known kneading method such as Banbury mixer, kneader, roll, single-screw or twin-screw extruder and cokneader. It

[0029]

The present invention will be described below in detail with reference to examples.

Examples 1 to 3 and Comparative Examples 1 and 2 The components shown in Table 1 were dry blended with a mixer in the composition ratio shown in Table 2. This is adjusted to a roll surface temperature of 90.
The mixture was heated and kneaded for 5 minutes using a mixin roll at ℃, cooled and pulverized to produce an epoxy resin composition.

Using this composition, molding was carried out under the conditions of 175 ° C. × 2 minutes by the low pressure transfer molding method, and the physical properties of each composition were measured by the following physical property measuring methods.

PCBT after the thermal cycle: Five 152pin QFPs mounted with simulated elements were molded at 180 ° C.
I post-cure it for 5 hours. -55 ° C to 150 ° C service
125 after repeating 100 cycles.
USPCBT was carried out at a temperature of 85% RH and a bias voltage of 10 V to determine the time at which the cumulative failure rate was 50%.

Water absorption rate: 10 pieces of 44 pin QFP were molded and post-cured at 180 ° C for 5 hours. The package
The test piece was allowed to stand for 96 hours in an environment of 85 ° C. and 85% RH, and the water absorption rate was determined.

Gel Time : The cure time of the composition was measured on a brass hot plate heated to 177 ° C.

[Table 1]

[Table 2] As seen in Table 2, the epoxy resin composition of the present invention (Examples 1-3) are not only has excellent moisture resistance reliability after thermal cycle, water absorption is also small.

On the other hand, Comparative Example 1 in which the curing agent (B) does not contain the curing agent (b) is inferior in moisture resistance reliability and water absorption after the thermal cycle property. Further, 4,4′-dihydroxy-3,3 ′, which has four methyl groups in one molecule,
5,5'-Tetramethylbiphenyl is inferior in reactivity and moisture resistance reliability after thermal cycle probably because of its large steric hindrance.

[0036]

Since the epoxy resin composition for semiconductor encapsulation of the present invention contains an epoxy resin, a filler, and a curing agent having a specific structure, it has a low water absorption rate and high moisture resistance reliability after a thermal cycle. Are better.

Claims (5)

(57) [Claims] 1. An epoxy resin composition for semiconductor encapsulation comprising an epoxy resin (A), a curing agent (B) and a filler (C), wherein the curing agent (B) is represented by the following formula (I): ) [Chemical 1] An epoxy resin composition for semiconductor encapsulation, comprising the biphenyl compound (b) represented by 2. The content of the biphenyl compound (b) is set to
The amount is 5 to 90% by weight with respect to the agent (B).
Epoxy resin composition for semiconductor encapsulation. 3. The total proportion of the filler (C) is 70 to 95 weight.
The epoxy for semiconductor encapsulation according to claim 1 or 2, which is the amount of
Resin composition. 4. The ratio of the epoxy resin (A) is 3 to 2 in the whole.
5% by weight, the compounding amount of the curing agent (B) is epoxy resin
The chemical equivalent ratio of (B) to (A) is 0.5 to 1.5.
The semiconductor encapsulation according to any one of claims 1 to 3,
Epoxy resin composition for use. 5. The semiconductor encapsulation according to claim 1.
Device encapsulated with an epoxy resin composition for use.