JPH07161879A - Resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To solve the charge property at molding of a semiconductor product by specifying the diameter of the grain of an inorganic filler, and making all resin composition contain a specified quantity of inorganic filler and all inorganic filler contain a specified quantity of spherical silica. CONSTITUTION:This composition contains epoxy resin, phenol novolak resin, a curing accelerator, and an inorganic filler as essential ingredients. Especially, the maximum grain diameter of the inorganic filler is 45mum or under, and the average gain diameter is 7-30mum, and 70-90wt.% out of all resin compositions is inorganic fillers. Furthermore, it is essential to contain spherical silica by 50wt.% or over in all inorganic fillers, and if it is under 50wt.%, the fluidity at molding drops remarkably. Hereby, this is excellent in the molding property of a thin part, and the charge property of a thin package 0.5-1.0mm thick is favorable, and a highly reliable semiconductor package without voids, uncharge, wire flow, and pad shift can be gotten.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable resin composition for semiconductor encapsulation which is excellent in moldability of a thin portion.

[0002]

2. Description of the Related Art For molding semiconductor elements such as transistors, ICs and LSIs, transfer molding of epoxy resin is adopted as a method suitable for low cost and mass production. It is at a level that can be used sufficiently by improvement. On the other hand, in the trend of lighter, thinner, shorter and smaller electronic products, semiconductor packages are becoming thinner and smaller year by year, and package thickness is an important characteristic for mounting on thin products found in IC cards, memory cards and liquid crystal devices. It's coming. A semiconductor package having a thickness of 1.0 mm to 0.5 mm will be required more and more in the future, and it is indispensable that the resin for semiconductor encapsulation has excellent filling properties in a thin portion. For example, in the case of a 0.5 mm thick package, if the chip is 200 μm thick and the lead frame is 150 μm thick, the resin sealing thickness is only 150 μm. Conventionally,
There is a method of using spherical silica having a maximum particle diameter of 74 μm in order to solve the filling property of the thin portion, but it has become insufficient for a thin package of 1.0 mm or less. Due to the improper particle size distribution, problems such as voids, unfilling, wire flow, and pad shift occurred.

[0003]

SUMMARY OF THE INVENTION The present invention provides a resin composition for semiconductor encapsulation for solving the filling property of such a semiconductor product at the time of molding.

[0004]

The present invention is an epoxy resin,
In a resin composition containing a phenol novolac resin, a curing accelerator, and an inorganic filler as essential components, the maximum particle size of the inorganic filler is 45 μm or less, and the average particle size is 7 to 30 μm.
In the resin composition for semiconductor encapsulation, 70 to 90 wt% of the total resin composition is an inorganic filler, and 50 wt% or more of the total inorganic filler is spherical silica.

The epoxy resin used in the present invention may be any one used in ordinary semiconductor encapsulating resin compositions,
Examples thereof include cresol novolac type epoxy, trifunctional epoxy, biphenyl type difunctional epoxy, bisphenol type epoxy, brominated epoxy and the like, but are not particularly limited. These epoxy resins may be used alone or in combination. The phenol novolac resin as the curing agent may be any one used in ordinary semiconductor encapsulating resin compositions, and examples thereof include phenol novolac type, cresol novolac type, paraxylene modified type, dicyclopentadiene type and modified resins thereof. However, it is not particularly limited. You may use these individually or in mixture. The curing accelerator may be any as long as it accelerates the reaction between the epoxy group and the phenolic hydroxyl group, and those generally used in the resin composition for semiconductor encapsulation can be widely used, such as benzyldimethylamine. Examples thereof include tertiary amines, imidazoles, organic phosphorus compounds such as 1,8-diazabicycloundecene, and triphenylphosphine, but are not particularly limited. These may be used alone or in combination.

In the inorganic filler used in the present invention, 50% by weight or more of the total inorganic filler is spherical silica, and the balance may be any of three kinds of crystalline silica, fused silica and alumina, which may be used alone or. You may mix and use it. The maximum particle size of the inorganic filler is 45 μm or less, and the average particle size is 7 to
30 μm is indispensable, and if the maximum particle size exceeds 45 μm, the filling property of the thin portion is poor and unfilling or voids occur. The maximum particle size of 45 μm or less in the present invention means a wet particle size of 45 μm.
Less than m is 98.0% by weight or more and 45 to 74 μm is 2.0
Weight% or less and 74 μm or more are defined as 0% by weight.
The wet particle size is a method in which 25 g of silica is uniformly dispersed in 500 cc of water, and the silica is allowed to flow on a sieve having a uniform mesh, and the weight% of silica remaining on the sieve is measured. The average particle size of the inorganic filler is 7 to 30 μm, and if it deviates from this range, the fluidity is remarkably inferior and the spiral flow is lowered.
In addition, voids are likely to occur. The content of the inorganic filler in the entire composition is 70 to 90% by weight. If the content is less than 70% by weight, the resin content increases and moisture absorption increases, so that the moisture resistance reliability deteriorates. If it exceeds 90% by weight, the resin content becomes too small and the fluidity at the time of molding is lowered. It is essential that the spherical silica in the total inorganic filler contains 50% by weight or more.
If it is less than 0% by weight, the fluidity at the time of molding remarkably decreases.

In the present invention, an epoxy resin, a phenol novolac resin, a curing accelerator and an inorganic filler are essential components. In addition to these, a silane coupling agent, antimony trioxide, hexabromobenzene and other flame retardants may be added if necessary. , Carbon black, colorants such as red iron oxide, natural wax,
A release agent such as a synthetic wax and various additives such as a low stress additive such as silicone oil and rubber may be appropriately blended. Further, in order to produce the encapsulating resin composition of the present invention as a molding material, after the epoxy resin, the phenol novolac resin, the curing accelerator, the inorganic filler, and other additives are sufficiently uniformly mixed by a mixer or the like. Further, it can be melt-kneaded with a hot roll or a kneader, cooled, and then pulverized to obtain a sealing material.

The present invention will be shown below with reference to examples. The blending ratio is shown in parts by weight. Example 1 Biphenyl type epoxy resin (Yuka Kagaku Co., Ltd., YX-4000H, epoxy equivalent 190, softening point 170 ° C.) 90 parts by weight Brominated epoxy resin (Nippon Kayaku Co., Ltd., BREN, epoxy equivalent 270, softening) Point 70 ° C) 10 parts by weight Phenol novolac resin (Sumitomo Durez Co., Ltd., PR series, hydroxyl group equivalent 104, softening point 80 ° C) 47 parts by weight Spherical silica A (maximum particle size 45μ, average particle size 15μ) 500 parts by weight Melt Silica A (maximum particle size 30 μ, average particle size 5 μ) 100 parts by weight Triphenylphosphine (Kitako Chemical Co., Ltd.) 2 parts by weight γ-glycidoxypropyltrimethoxysilane (Nippon Unicar Co., Ltd., A-187) ( Hereinafter referred to as epoxysilane) 4 parts by weight Antimony trioxide 10 parts by weight Carnauba wax 3 parts by weight Carbon black 2 parts by weight The parts were thoroughly mixed at room temperature, then kneaded at 80 to 100 ° C. using a biaxial heating roll, cooled, pulverized and tableted to obtain a resin composition for semiconductor encapsulation. This material was molded using a transfer molding machine at 175 ° C. and an injection pressure of 120 kg / cm ² to obtain a test piece for evaluation. The evaluation results are shown in Table 1.

Evaluation method Sparral flow: According to the EMMI method. Fillability of 0.5 mm thick package: 52 with simulated element
pQFP (14 x 14 x 0.5 mm, chip 6 x 6 x
0.23 mm, lead frame thickness 0.15 mm) 17
Transfer molding is performed at 5 ° C and the filling property of the resin is judged. Moisture resistance reliability failure rate: 52pQFP (1
4 x 14 x 1.0 mm, chip 6 x 6 x 0.30 mm)
Reflow treatment (85 ° C, 85% RH, 72H
After moisture absorption treatment, 240 ° C reflow treatment), then 125
Al after 500hr treatment by PCT test at 2.3 ° C at 2.3 ° C
Judgment is based on the number of wiring defects. Example 2 A resin composition for semiconductor encapsulation was obtained in the same manner as in Example 1 except that the formulation shown in Table 1 was used. The evaluation results are shown in Table 1. Comparative Examples 1 to 5 Using the formulations shown in Table 1, a resin composition for semiconductor encapsulation was obtained in the same manner as in Example 1. The evaluation results are shown in Table 1.

[0010]

[Table 1]

[0011]

The resin composition for semiconductor encapsulation of the present invention is excellent in moldability of the thin portion and has a package thickness of 0.5 to 0.5.
A 1.0 mm thin package has a good filling property, and a highly reliable semiconductor package can be obtained without generation of voids, unfilling, wire flow and pad shift.

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Claims (1)

[Claims] 1. A resin composition comprising an epoxy resin, a phenol novolac resin, a curing accelerator, and an inorganic filler as essential components, wherein the inorganic filler has a maximum particle size of 45 μm or less and an average particle size of 7 to 30 μm. 70 in total resin composition
A resin composition for semiconductor encapsulation, characterized in that ˜90 wt% is an inorganic filler, and 50 wt% or more of the total inorganic filler is spherical silica.