JPH05160302A - Resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To improve solder heat resistance, low stress, low water absorptive property, and adhesion by adding silica for filling in high density to epoxy resin, using a low water absorptive curing agent. CONSTITUTION:This is composed at a ratio of 300-2000 pts.wt. for silica for filling and 20-100 pts.wt. for curing agent to 100 pts.wt. for epoxy resin. As the epoxy resin, 0-cresol novolak type epoxy resin is used. For the silica for filling, the globular silica 10mum or more in grain diameter and smashed silica 10mum or less in grain diameter are used in combination. The globular silica 10mum in grain diameter is in a range of 20-80% of the all silica for filling. A low water absorptive curing agent expressed by the formula is used as the curing agent. Moreover, as the curing agent, it can be used by mixing phenol novolak resin in itself. At this time, for the curing agent expressed by the formula, 30wt.% or more out of all the quantity of the curing agent is added. Hereby, cracks can be prevented by improving low stress and low water absorption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for semiconductor encapsulation which has excellent solder heat resistance, low viscosity, low water absorption, low stress and excellent moldability.

[0002]

2. Description of the Related Art In recent years, high integration of semiconductor devices has been rapidly advanced, and the size of elements and the miniaturization of wiring width have been remarkably advanced. This is largely due to the development of a sealing resin having excellent performance as well as reliability.

On the other hand, in mounting components on a printed circuit board, a DIP package which is an insertion type package has been changed to a SOP package which is a surface mounting type package for high density mounting and streamlining of work.

Further, in recent years, for higher density mounting,
The SOP and QFP packages, which are the first generation of surface mount devices, are being moved to TSOP and TQFP packages, which have been made thinner. With the thinner package,
The resin thickness on the top surface of the chip is becoming very thin. For this reason, cracking of the resin portion due to heating during mounting has become a more serious problem.

The occurrence of cracks in the soldering process is
It is said that peeling occurs on the back surface of the package die pad between the post-curing and the mounting process, and the accumulated water vaporizes and expands explosively during soldering heating. A method is adopted in which after post-curing, the product is completely dried, moisture-proof packed and shipped.

Improvements in sealing resins have also been investigated. For example, there is a method in which a rubber component is mixed with a sealing resin to reduce the internal stress, a method in which a filler is highly filled to reduce the linear expansion coefficient (JP-A-63-189421, JP-A-63-63421). 16445 publication). The surface of the filler is treated with a coupling agent to improve the adhesiveness at the interface between the resin and the filler.
A method of increasing the strength has been proposed (Japanese Patent Laid-Open No. 61-22).
1222).

[0007]

In the above-mentioned conventional method, the moisture-proof packaging method requires complicated product handling,
Manufacturing cost rises.

Further, the encapsulating resins improved by various methods have been gradually effective, but they are not sufficient to meet the higher soldering heat resistance requirements accompanying the progress of mounting technology. For example, lowering the stress by adding a rubber component is still insufficient for the surface mounting second generation TSOP and TQFP packages, and compounding a rubber component causes a decrease in bending strength and a decrease in solder heat resistance. .. The method of highly filling the filler has a drawback that when crushed silica is used, the fluidity is reduced, molding becomes difficult, and the use of spherical silica causes a reduction in strength. Further, the effect of treating the surface of the filler with the coupling agent is not sufficient to meet the demand.

An object of the present invention is to solve the above problems and provide a resin composition for semiconductor encapsulation which has excellent solder heat resistance, low stress, low water absorption, and excellent adhesion and moldability.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a low water-absorption curing agent is used and the filling silica is filled at a high density. The present invention has been completed based on the finding that the above problems can be solved.

That is, the present invention relates to (a) epoxy resin 1
00 parts by weight, (b) 300 to 2000 parts by weight of silica for filling, (c) the following general formula (1)

[Chemical 2] The resin composition for semiconductor encapsulation is characterized by containing 20 to 100 parts by weight of a curing agent represented by

By using a low water-absorbing curing agent and highly filling silica for filling, the linear expansion coefficient is lowered while maintaining the fluidity, and the viscosity is low, the stress is low, and the water absorption is excellent. A cured product having excellent solder resistance can be obtained.

The epoxy resin used in the present invention includes:
Known compounds such as o-cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and biphenyl type epoxy resin can be used.

In order to maximize the effects of the present invention, it is preferable to use spherical silica having a particle size of 10 μm or more and crushed silica having a particle size of 10 μm or less, and the total amount of silica is 100 parts by weight of the epoxy resin. Against 50
It is preferable to add 0 part by weight or more. Also, the particle size 10
Spherical silica with a size of μm or more is 20 to 80 of the total filling silica.
% Range is preferred. If it is less than this range, the fluidity is lowered, and if it is more than this range, the strength is lowered and the desired effect cannot be obtained.

As the curing agent, the following general formula (1)

[Chemical 3] It is preferable to use the entire amount of the curing agent represented by, but it is also possible to use it in combination with other cured products. As other curing agents, known ones such as phenol novolac resin and acid anhydride can be used. At this time, the curing agent represented by the general formula (1) is preferably added in an amount of 30% by weight or more based on the total amount of the curing agent. Below this, the water absorption characteristics deteriorate and the solder heat resistance decreases. Further, the curing agent is 30 to 80 parts by weight with respect to 100 parts by weight of the epoxy resin, and preferably the ratio of the epoxy equivalent and the phenolic hydroxyl group equivalent is 1: 0.8 to 1.
It is 2. When the ratio of the phenolic hydroxyl group equivalent is less than this range, curability, strength and water absorption properties are deteriorated and solder heat resistance is reduced.

In the present invention, a curing accelerator can be blended in addition to the epoxy resin curing agent. Known curing accelerators can be used, and suitable curing accelerators include, for example, triphenylphosphine, imidazole, 1,8-diazabicyclo [5,4,0] undecene-1 and the like. The addition amount varies depending on the curing accelerator used, and for example, in the case of triphenylphosphine, the range is preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin.

In the resin composition for semiconductor encapsulation of the present invention, if necessary, a release agent such as OP wax and carnauba wax, a coupling agent such as γ-glyoxypropyltrimethoxysilane, carbon black and the like. It is also possible to add a colorant, a flame retardant such as antimony trioxide.

The resin composition for semiconductor encapsulation of the present invention is mixed, kneaded, pulverized, and then heat-molded according to a conventionally known method to obtain a semiconductor device in which a semiconductor element is encapsulated.

[0019]

EXAMPLES The present invention will be described in more detail below by showing Examples of the present invention. Example 1 o-cresol novolac type epoxy resin (YDCN-
702, manufactured by Tohto Kasei Co., Ltd .; hereinafter referred to as epoxy resin A),
Formula (2) below

[Chemical 4] Curing agent represented by (hereinafter referred to as curing agent A), average particle size 2
After mixing 1 μm spherical fused silica powder, crushed fused silica powder having an average particle size of 6 μm, a curing accelerator (triphenylphosphine), and other additives in the proportions shown in Table 1, using a mixing roll at 110 ° C. Knead for 4 minutes,
After cooling, the mixture was pulverized to prepare a sealing resin composition. The spiral flow was measured using these sealing resin compositions. A test piece was prepared using the same sealing resin composition, and the bending strength and bending elastic modulus were measured. Furthermore, 84p
After molding inIC and post-curing, moisture absorption was performed for 24 hours, 48 hours and 72 hours in a high temperature and humidity chamber at 85 ° C and 85%, and then the water absorption rate was measured, and the back surface of the die pad was peeled off with an ultrasonic flaw detector. After observing the
It was immersed for 2 seconds, and the crack of the package was observed. The results are shown in Table 1.

From the results shown in Table 1, it can be seen that the resin composition for semiconductor encapsulation of the present invention is excellent in fluidity, strength, adhesion, water absorption and solder heat resistance.

Example 2 Epoxy resin A, the following formula (3)

[Chemical 5] Curing agent represented by (hereinafter referred to as curing agent B), average particle size 2
1 μm spherical fused silica powder, crushed fused silica powder having an average particle size of 6 μm, a curing accelerator (triphenylphosphine), and other additives were mixed in the proportions shown in Table 1 and then mixed in the same manner as in Example 1. The physical properties were measured.

Example 3 Phenol novolac type epoxy resin (YDPN-63
8, manufactured by Toto Kasei Co., Ltd .; hereinafter referred to as epoxy resin B), curing agent A, spherical fused silica powder having an average particle size of 21 μm, crushed fused silica powder having an average particle size of 6 μm, curing accelerator (triphenylphosphine), etc. Each of the additives was mixed in the proportions shown in Table 2, and then the physical properties were measured in the same manner as in Example 1.

Example 4 Epoxy resin B, curing agent B, spherical fused silica powder having an average particle size of 21 μm, crushed fused silica powder having an average particle size of 6 μm,
After curing accelerator (triphenylphosphine) and other additives were mixed in the proportions shown in Table 1, each physical property was measured in the same manner as in Example 1.

Comparative Example 1 Epoxy resin A, phenol novolac curing agent (PSF
-4224, manufactured by Gunei Chemical Co., Ltd .; hereinafter referred to as curing agent C), spherical fused silica powder having an average particle size of 21 μm, average particle size of 6 μm
The crushed fused silica powder, the curing accelerator (triphenylphosphine), and the other additives were mixed in the proportions shown in Table 3, and then the physical properties were measured in the same manner as in Example 1.

Comparative Example 2 Epoxy resin B, curing agent C, spherical fused silica powder having an average particle size of 21 μm, crushed fused silica powder having an average particle size of 6 μm,
After curing accelerator (triphenylphosphine) and other additives were mixed in the proportions shown in Table 3, each physical property was measured in the same manner as in Example 1.

[0026]

According to the resin composition for semiconductor encapsulation of the present invention, it is possible to obtain a cured product having low stress, low water absorption and excellent solder heat resistance while maintaining fluidity. By using it, a good semiconductor without cracks can be obtained.

[Table 1]

[Table 2]

Claims (1)

[Claims] 1. (a) 100 parts by weight of epoxy resin, (b) 300 to 2000 parts by weight of silica for filling, (c) the following general formula (1) A resin composition for semiconductor encapsulation, comprising 20 to 100 parts by weight of a curing agent represented by as an essential component.