JPH04275325A - Resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To provide a resin composition for sealing semiconductors, useful as a resin composition for sealing the semiconductors, excellent in solder heat resistance and improved in moldability with a low stress. CONSTITUTION:A resin composition for sealing semiconductors containing (a) 100 pts.wt. epoxy resin having <=1 melt viscosity at 150 deg.C or an epoxy resin containing >=30wt.% aforementioned epoxy resin, (b) 300-1000 pts.wt. silica for filling, (c) 1-50 pts.wt. epoxy-modified liquid polybutadiene and (d) 20-100 pts.wt. curing agent. Since cured products excellent in strength and heat resistance can be obtained, excellent semiconductors without causing cracks can be obtained.

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 that has excellent soldering heat resistance, low stress and excellent moldability, and a semiconductor device using the same.

0002

2. Description of the Related Art In recent years, the integration of semiconductor devices has rapidly progressed, and the size of elements has increased and wiring widths have become finer. Most semiconductor devices, including highly integrated semiconductor devices, are currently sealed with resin. This is largely due to the development of a sealing resin that is highly reliable and has excellent performance.

On the other hand, in mounting components onto printed circuit boards, there has been a shift from DIP packages, which are insert-type packages, to SOP packages, which are surface-mount packages, in order to achieve high-density mounting and streamline workability. In line with this, a method of using biphenyl type epoxy resin as the epoxy resin has been proposed (JP-A-58-39677, JP-A-61-47725, JP-A-61-2).
59552).

[0004] Also, in recent years, due to higher density packaging,
SOP and QFP packages, which were the first generation of surface mount devices, are now transitioning to thinner TSOP and TQFP packages.

[0005] As packages become thinner, the thickness of the resin on the top surface of the chip has become extremely thin. For this reason, cracks in the resin portion due to heating during mounting have become a more serious problem. Cracks occur during the soldering process because peeling occurs on the back of the package die pad between post-curing and the mounting process, and the moisture that accumulates there explosively evaporates and expands during soldering heat. As a countermeasure to this problem, the method of post-curing, completely drying, and shipping in moisture-proof packaging has been adopted.

[0006] Improvements in the sealing resin have also been studied. For example, there is a method of blending a rubber component into the sealing resin to reduce internal stress, a method of using a new structural resin, and a method of lowering the coefficient of linear expansion by filling the sealing resin with a high amount of filler (Japanese Unexamined Patent Application Publication No. 1983-1989-1). Publication No. 189421, Japanese Unexamined Patent Publication No. 16445/1983
Publication No.). In addition, a method has been proposed to improve the adhesion between semiconductor chips and lead frames and prevent peeling by adding an oil component (Japanese Unexamined Patent Publication No. 62-141018
Publication No.).

[0007]

[Problems to be Solved by the Invention] In the above-mentioned prior art, the moisture-proof packaging method complicates handling of the product and increases manufacturing costs.

[0008] In addition, resins improved by various methods are gradually becoming more effective, but they are not sufficient to meet the more advanced demands that accompany advances in packaging technology. For example, the method of blending a rubber component leads to a decrease in bending strength, the high filling of crushed silica has a limit in terms of fluidity, and the use of spherical silica to improve fluidity leads to a decrease in strength. There is. Specifically, semiconductor devices sealed by these conventional methods are heated to 85°C after moisture absorption treatment.
If solder immersion is performed 72 hours after the /85% RH treatment, blisters or cracks will occur on the back surface of the package die pad. That is, a sealing resin that completely prevents cracks during soldering has not been obtained, and there is a desire to develop a sealing resin that has better soldering heat resistance.

Therefore, an object of the present invention is to solve the above-mentioned problems and provide a resin composition for semiconductor encapsulation which has excellent soldering heat resistance, low stress, and excellent moldability.

0010

[Means for Solving the Problems] The present inventors conducted intensive research to solve the above problems, and found that the melt viscosity is 1.
The present invention was completed based on the knowledge that the above-mentioned problems can be solved by adding epoxy-modified polybutadiene to an epoxy resin of P or less and filling it with silica at a high density.

That is, the present invention provides (a) an epoxy resin having a melt viscosity of 1P or less at 150°C, or an epoxy resin 100 containing 30% by weight or more of the same;
Semiconductor packaging comprising (b) 300 to 1000 parts by weight of silica for filling, (c) 1 to 50 parts by weight of epoxy-modified liquid polybutadiene, and (d) 20 to 100 parts by weight of a curing agent, based on the weight part. It is a resin composition for curing, and preferably has the following general formula (1) as a curing agent.

This is a resin composition for semiconductor encapsulation characterized by using a polyhydric phenol having at least two phenolic hydroxyl groups represented by the following formula.

[0012] By using an epoxy resin with a melt viscosity of 1P or less, filling it with high filler silica, and adding liquid polybutadiene, while maintaining fluidity, the coefficient of linear expansion is lowered, and the modulus of elasticity is further lowered. Excellent adhesion with low stress,
A cured product with excellent solder resistance can be obtained.

[0013] By using an epoxy resin having a melt viscosity of 1 P or less, a cured product having excellent soldering heat resistance can be obtained. The epoxy resin used in the present invention is an epoxy resin that melts at 100°C or higher, and particularly has a melt viscosity of 1P or lower at around 150°C. A typical example of such an epoxy resin is a biphenyl type epoxy resin. It is preferable that the entire amount of the epoxy resin be an epoxy resin having a melt viscosity of 1 P or less, such as a biphenyl type epoxy resin, but it can also be used in combination with other epoxy resins. As other epoxy resins that can be used in combination with epoxy resins having a melt viscosity of 1P or less, such as biphenyl epoxy resins, known ones such as o-cresol novolac epoxy resins and bisphenol A epoxy resins can be used. At this time, an epoxy resin having a melt viscosity of 1 P or less, such as a biphenyl type epoxy resin, is used in an amount of 30% by weight or more based on the total amount of the epoxy resin. If the amount is less than this, the soldering heat resistance will deteriorate.

In order to maximize the effects of the present invention, it is necessary to use 2 to 98% by weight of spherical silica with a particle size of 10 μm or more and 2 to 98% by weight of crushed silica with a particle size of 10 μm or less as filler silica.
98% by weight, the total is 10% by weight of epoxy resin
It is preferable to add 500 parts by weight or more to 0 parts by weight. More preferably, the spherical silica having a particle size of 10 μm or more is in the range of 20 to 80% by weight of the total filling amount of the filling silica. If the amount is less than this range, no fluidity improvement effect will be obtained, and if it is more than this, the strength will decrease and the soldering heat resistance will deteriorate.

The liquid polybutadiene preferably has an average molecular weight of about 500 to 5,000. If the average molecular weight is less than 500, bleed-out occurs during molding and mold stains occur. Also, the average molecular weight is 50
If it exceeds 00, the viscosity increases and kneading becomes difficult.
In addition, adhesion is reduced. The liquid polybutadiene is an epoxy-modified polybutadiene in which an epoxy group is introduced into liquid polybutadiene. A suitable range of epoxy equivalent is about 60 to 500; if it is smaller than this range, the concentration of epoxy groups will increase, which will have a negative effect on fluidity, and if it exceeds this range, the resin will deteriorate due to the introduction of epoxy groups. The adhesive effect of liquid polybutadiene cannot be obtained.

The curing agent is preferably used in an amount of 20 to 100 parts by weight, more preferably 30 parts by weight, based on 100 parts by weight of the epoxy resin.
Add ~70 parts by weight. Particularly preferable curing agents include the following general formula (1):

It is a polyhydric phenol having at least two phenolic hydroxyl groups represented by the following formula. By using this, a cured product with excellent solder heat resistance can be obtained. Although it is preferable to use the curing agent represented by the above general formula (1) alone, it can also be used in combination with other curing agents. In this case, it is desirable to use the curing agent represented by the above general formula (1) in an amount of 30% by weight or more based on the total amount of the curing agent. If the amount is less than this, the strength and solder heat resistance will decrease.

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

The resin composition for semiconductor encapsulation of the present invention may also contain, if necessary, a mold release agent such as OP wax or carbana wax, a coupling agent such as γ-glytoxypropyltrimethoxysilane, carbon black, etc. colorant,
Flame retardants such as antimony trioxide may also be added.

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

[0020]

EXAMPLES Examples of the present invention will be shown below to explain the present invention in more detail.

Examples 1 to 2 Biphenyl-type epoxy resin (manufactured by Yuka Shell Co., Ltd., YX-4000) with a melt viscosity of 0.2P (150°C), curing agent (tetraphenol ethane), and spherical fused silica with an average particle size of 21 μm. After mixing the powder, crushed fused silica powder with an average particle size of 6 μm, liquid epoxy-modified polybutadiene with an average molecular weight of 2000 and an epoxy equivalent of 120, a curing accelerator (triphenylphosphine), and other additives in the proportions shown in Table 1, Using a mixing roll, the mixture was kneaded at 110° C. for 4 minutes, cooled, and then pulverized to prepare a sealing resin composition. Spiral flow was measured using these sealing resin compositions. In addition, test pieces were prepared using the same sealing resin composition, and the bending strength and bending elastic modulus were measured. Furthermore, 8
After molding 4pin IC and post-curing, 85℃, 85
Absorb moisture in a constant temperature and humidity chamber for 24 hours, 48 hours, and 7%.
After 2 hours, the package was immersed in a 260° C. solder bath for 10 seconds, and cracks in the package were observed. These 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, and soldering heat resistance.

Examples 3 to 4 Biphenyl type epoxy resin (manufactured by Yuka Shell Co., Ltd., YX-4000) with melt viscosity 0.2P (150°C), curing agent (phenol novolak resin, softening point 100°C), average particle size Spherical fused silica powder of 21 μm, crushed fused silica powder with average particle size of 6 μm, average molecular weight 2000, epoxy equivalent 1
20 liquid epoxy modified polybutadiene, curing accelerator (
Triphenylphosphine) and other additives were mixed in the proportions shown in Table 1, and then the physical properties were measured in the same manner as in Example 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, and soldering heat resistance.

Comparative Example 1 Only spherical fused silica powder with an average particle size of 21 μm was used as a filler, and liquid polybutadiene was not used, but the mixture was mixed in the proportions shown in Table 1, and each physical property was measured in the same manner as in Example 1. . The results are shown in Table 1.

Comparative Example 2 Using only fused crushed silica powder with an average particle size of 6 μm as a filler, without using liquid polybutadiene, the mixture was mixed in the proportions shown in Table 1, and the physical properties were measured in the same manner as in Example 1. did. The results are shown in Table 1.

[Table 1]

[0027]

[Effects of the Invention] As described above, by using the resin composition of the present invention, it is possible to obtain a cured product with low stress and excellent soldering heat resistance while maintaining fluidity. Accordingly, a good semiconductor without cracks can be obtained.

Claims (3)

[Claims] Claim 1: (a) 100 parts by weight of an epoxy resin having a melt viscosity of 1 P or less at 150°C or an epoxy resin containing 30% by weight or more thereof, (b) 300 to 1000 parts by weight of silica for filling ( c) 1 to 50 parts by weight of epoxy-modified liquid polybutadiene; and (d) 20 to 100 parts by weight of a curing agent. A resin composition for semiconductor encapsulation comprising as essential components. 2. Claim 1, wherein the filling silica comprises 2 to 98% by weight of spherical silica having a particle size of 10 μm or more and 2 to 98% by weight of crushed silica having a particle size of 10 μm or less.
The resin composition for semiconductor encapsulation described above. 3. The semiconductor encapsulation method according to claim 1, wherein the curing agent is a polyhydric phenol having at least two phenolic hydroxyl groups represented by the following general formula (1): Resin composition.