JPH0782460A - Epoxy resin composition for sealing - Google Patents

Abstract

PURPOSE:A high thermal conductivity epoxy resin composition for sealing containing more than 80% of crystalline silica of high heat dissipation type where it can effectively do sealing with good full-mode filling causing no wire sweep such as aluminum wire sweep. CONSTITUTION:In an epoxy resin composition for sealing containing over 80wt.% of crystalline silica, the crystalline silica of 1 to 5mum particle distribution and 1.5 to 3mum average particle size amounts for 10 to 30wt.% of the crystalline silica content, 50 to 70wt.% distribute from 10 to 100mum with 35 to 40 average size and 20 to 30wt.%, 90 to 120mum on the average.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electric parts, electronic parts,
The present invention relates to a sealing epoxy resin composition for sealing a semiconductor element or the like.

[0002]

2. Description of the Related Art In recent years, a package having a small thermal resistance has been demanded in order to improve the reliability of power devices such as power ICs and power transistors. In the case of the full-mold type package of MyCares specification, the thickness of the molded resin product that covers the heat dissipation part of the lead frame tends to become thinner in order to improve heat dissipation and reduce thermal resistance. . Further, in order to improve the heat dissipation property, a sealing epoxy resin composition containing high thermal conductivity crystalline silica so as to be filled as high as possible is used.

As a sealing epoxy resin composition highly filled with silica, for example, JP-A-2-276814 discloses an epoxy resin, a phenol novolac resin, a curing accelerator, a maximum particle size of 130 μm or less, and an average particle size. Is 30 μm
Disclosed is a composition comprising the following crushed silica and / or spherical silica having a maximum particle size of 200 μm or less and an average particle size of 50 μm or less, and having a silica content of 54 to 87% by weight. Is said to have a low molding shrinkage and good crack resistance and moisture resistance.

In this way, the performance of electric and electronic equipment is improved,
Plastic sealing is performed for high reliability and productivity improvement. Among them, high thermal conductive crystalline silica is used for sealing epoxy resin composition 8 to improve heat dissipation.
When it is contained in a large amount of 0% by weight or more, there is a problem that the melt viscosity increases and the fluidity decreases. This problem is caused, for example, by increasing the number of cavities at the time of encapsulation molding, the size of the mold becomes larger, and the semiconductor device is molded by such a mold, and there are a thick part and a thin part. When a product is molded, it is easy to fill thick parts due to poor fluidity, but it is difficult to fill thin parts, so some parts become unfilled,
That is, the full mold filling property is deteriorated, and the melt viscosity is high, so that, for example, aluminum wire sweep is generated, resulting in deterioration of sealing moldability.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks, and an object thereof is to highly fill crystalline silica containing 80% by weight or more of crystalline silica having a good heat dissipation property. In the encapsulating epoxy resin composition for high heat conduction of the mold, the full mold filling property is good, for example, wire sweep such as aluminum wire sweep does not occur,
An object of the present invention is to provide an epoxy resin composition for encapsulation having good encapsulation moldability.

[0006]

The epoxy resin composition according to the present invention has a particle size distribution of 1 to 5 μm in an epoxy resin composition for encapsulation containing 80% by weight or more of crystalline silica, and has an average particle size. The crystalline silica, which is 1.5 to 3 μm,
10 to 30% by weight of the crystalline silica content, 10 to 1
The crystalline silica having a particle size distribution of 00 μm and an average particle size of 35 to 40 μm is 50 to 70% by weight of the crystalline silica content and has a particle size distribution of 70 to 130 μm and an average particle size of 90 to 120 μm. The crystalline silica is characterized in that it is 20 to 30% by weight of the crystalline silica content.

[0007]

According to the present invention, the epoxy resin composition comprises
Fine-grained crystalline silica having a particle size distribution of 5 μm and an average particle size of 1.5 to 3 μm has a crystalline silica content of 10
˜30 wt%, having a particle size distribution of 10 to 100 μm, the intermediate particles of crystalline silica having an average particle size of 35 to 40 μm are 50 to 70% by weight of the crystalline silica content and 70 to 130 μm. Has a particle size distribution of 90 and an average particle size of 90
The coarse particles, the intermediate particles and the fine particles are appropriately mixed such that the coarse particles of crystalline silica having a particle size of 120 μm are 20 to 30% by weight of the content of the crystalline silica. Become. That is, since the voids are reduced and the wettability between the epoxy resin and the crystalline silica is improved, the crystalline silica can be covered with a small amount of the epoxy resin. As a result, the melt viscosity is lowered and the fluidity is good.

The present invention will be described in detail below. The epoxy resin used in the present invention includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, flexible epoxy resin, halogenated epoxy resin,
It is possible to use general epoxy resins such as glycidyl ester type epoxy resin and polymer type epoxy resin.

Although it is not excluded to use an inorganic filler such as fused silica, talc, clay, calcium carbonate, aluminum hydroxide, glass fiber or ceramic fiber, the content of crystalline silica is 70% by weight or less. The thermal conductivity is 35 × 10 ⁻⁴ cal / cm · s · ° C. or less, and when the crystalline silica is replaced with fused silica, the thermal conductivity is 20 even if the content of fused silica is 80% by weight or more. ×
It becomes about 10 ⁻⁴ cal / cm · s · ° C., and heat dissipation becomes poor.

Therefore, in order to maintain good heat dissipation, it is a prerequisite that crystalline silica is contained in an amount of 80% by weight or more. When the crystalline silica is contained in an amount of 80% by weight or more, the thermal conductivity becomes 50 × 10 ⁻⁴ cal / cm · s · ° C. or more, and the heat dissipation is good. In addition to this condition, fine particles of crystalline silica having a particle size distribution of 1 to 5 μm and an average particle size of 1.5 to 3 μm are 10 to 30% by weight of the crystalline silica content, and 10 to 100 μm. Intermediate particles of crystalline silica having a particle size distribution and an average particle size of 35-40 μm
50 to 70% by weight of the crystalline silica content, and 70
Having a particle size distribution of ˜130 μm and an average particle size of 90˜120
When the crystalline silica of the coarse particles having a particle size of 20 μm is 20 to 30% by weight of the crystalline silica content, the coarse particles and the intermediate particles contribute to the thermal conductivity, but on the other hand, hinder the full mold filling property. For example, since it causes the aluminum wire sweep to deteriorate the sealing moldability, in order to improve the sealing moldability, fine particles of crystalline silica are blended,
Coarse particles, medium particles and fine particles are well balanced and close to close packing, improving moldability. That is, when the density is close to the closest packing, the voids are reduced and the wettability between the epoxy resin and the crystalline silica is improved, so that the crystalline silica can be covered with a small amount of the epoxy resin. As a result, the melt viscosity is lowered and the fluidity is improved.

As the cross-linking agent and / or the curing agent, a phenol resin, a melamine resin, an acrylic resin, an isocyanate, an amine-based curing agent, an acid anhydride or the like may be used if necessary, and there is no particular limitation.

As the curing accelerator used as required, phosphorus-based and / or tertiary amine-based curing accelerators can be used.

As the release agent, a commonly used substance such as metal soap, wax and stearic acid can be used as it is.

In this way, the above materials are blended, mixed,
The epoxy resin composition for encapsulation is obtained by kneading, pulverizing, and granulating if necessary.

Further, the epoxy resin composition for sealing is molded by compression molding, transfer molding, injection molding or the like.

With the above composition, there is no possibility that a portion not filled with resin will be generated at the time of encapsulation and the filling property of the full mold will be deteriorated. For example, aluminum wire sweep will occur. That is not the case, and the sealing moldability is improved.

That is, according to the present invention, heat dissipation and
To obtain a high-conductivity encapsulating epoxy resin composition of crystalline silica containing 80% by weight or more of crystalline silica having a good full mold filling property, no wire sweep, and good encapsulation moldability. You can

[0018]

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

Regarding the compounding ingredients of Examples 1 to 3 and Comparative Examples 1 to 3, 82 parts by weight of crystalline silica was used, and the content was the compounding amount shown in Table 1, and the other compounding ingredients were
The following substances were used in their respective amounts.

The epoxy resin has an epoxy equivalent of 20.
0, 10 parts by weight of an ortho-cresol novolac epoxy resin having a softening point of 80 ° C., and a hydroxyl equivalent of 1 as a curing agent.
05, 5 parts by weight of phenol novolac resin having a softening point of 100 ° C., 0.1 part by weight of dimethylimidazole as a curing accelerator, 0.1 part by weight of carbon black as a colorant, and 0.4 part by weight of epoxysilane as a coupling agent. , 0.4 parts by weight of carnauba wax as a release agent, and flame retardant 2
Parts by weight were used respectively.

In each of the above Examples and Comparative Examples, the surface of crystalline silica was treated with epoxysilane as a coupling agent, and the above-mentioned components were uniformly mixed and dispersed in a mixer for 3 minutes, and then the roll temperature was 100 to 120 ° C. The mixture was heated, melted and kneaded with a mixing roll of. This kneaded product was cooled and pulverized to obtain an epoxy resin molding material for encapsulation made of each epoxy resin composition.

Spiral flow, gel time and melt viscosity were measured using each of the epoxy resin compositions obtained above, and the results are shown in the evaluation column of Table 1.

Further, each epoxy resin composition was molded using a transfer molding machine at a mold temperature of 175 ° C. and a molding pressure of 50 k.
The semiconductor element was sealed and molded at g / cm ² .

The thermal conductivity was measured by a rapid thermal conductivity meter (QTM-D2 manufactured by Showa Denko), and Examples 1 to 3 and Comparative Example 1 were used.
All of No. 3 to No. 3 were 50 × 10 ⁻⁴ cal / cm · s · ° C. or higher, and the heat dissipation was good.

[0025]

[Table 1]

The measured values shown in Table 1 were obtained by the following method. (1) Spiral flow Using a mold conforming to the EMMI 1-66 standard, the mold surface temperature was 170 ° C. and the molding pressure was 70 kg / cm ² . (2) Gel time Gel time measuring machine (JSR type CURELASTOME
(TER) was used and the mold surface temperature was measured at 170 ° C. (3) Melt viscosity Monohole flow tester (SHIMAZU FLO
WTESTER) and a heating furnace temperature of 175 ° C. and a plunger pressure of 10 kg / cm ² . (4) Particle size distribution A laser diffraction type particle size distribution measuring device (manufactured by Seishin Enterprise: PRO-7000S) was used as a particle size distribution measuring device.

Regarding the full mold filling property, the sealing molded product was visually observed, and the one with good filling property, which had no chipping and had an extremely smooth surface, was indicated by ◯, and there was a chipping and no smoothness. Poor packing properties are shown by x, and those with no chipping in the middle but rough surface are shown by Δ.

The aluminum wire sweeping property was shown by observing the sealed molded article by soft X-ray, that the aluminum wire was in the original shape, and that the aluminum wire was bent even slightly was x.

As shown in Table 1, according to the present invention as in Examples 1 to 3, the melt viscosity was 1000 P or less, the fluidity was good, the full mold filling property was good, and the aluminum wire sweep was not generated.

On the other hand, in Comparative Examples 1 to 3, the melt viscosity was 1500 P or more, the fluidity was poor, and aluminum wire sweep occurred. Further, in Comparative Examples 2 and 3, the full mold filling property was also poor.

[0031]

According to the epoxy resin composition of the present invention,
In addition to good heat dissipation, the melt viscosity is low and the fluidity is good, so the full mold fillability is good and the occurrence of wire sweep such as aluminum wire sweep can be prevented.

Claims (1)

[Claims] 1. An epoxy resin composition for encapsulation containing 80% by weight or more of crystalline silica, wherein the crystalline silica having a particle size distribution of 1 to 5 μm and an average particle size of 1.5 to 3 μm contains crystalline silica. 10 to 30% by weight of the amount, 10
Having a particle size distribution of ˜100 μm and an average particle size of 35-40 μm
The crystalline silica which is m has a crystalline silica content of 50 to 70.
Epoxy resin for encapsulation, characterized in that crystalline silica having a particle size distribution of 70 to 130 μm and an average particle size of 90 to 120 μm is 20 to 30% by weight of the crystalline silica content. Composition.