JPH0496963A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition suitable as a semiconductor molding material having high thermal conductivity, excellent heat-cycle properties with only a slight mold wearing containing a crystalline silica and a silicon nitride having specific averaged particle diameter as inorganic fillers. CONSTITUTION:(A) An epoxy resin composition containing epoxy resin (e.g. cresol-novolak type or bisphenol-A type), a crosslinking agent (preferably phenolic resin, etc., having 80-120 OH equivalent and 60-120 deg.C softening point), a hardener and a hardening accelerator, etc., is mixed with (B) B1: spherical crystalline silica having 10-40mum averaged particle diameter and preferably <=2.2 maximum value of shape factor and B2: silicon nitride having <=10mum averaged particle diameter as inorganic fillers and arbitrarily with other inorganic filler (e.g. molten silica, aluminum hydroxide or clay), then uniformly blended, melted by heating, cooled and crushed to afford the objective epoxy resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molding material resin composition. In particular, the present invention relates to a molding material resin composition for semiconductors having excellent high thermal conductivity.

[Prior art]

2. Description of the Related Art In recent years, packages with low thermal resistance are required in order to improve the durability and reliability of power devices such as power ICs and power transistors. In full mold type packages such as TO220 and TO3 with micaless specifications, the thickness of the sealing resin molded product that covers the heat dissipation part of the lead frame is becoming thinner and thinner to improve heat dissipation and reduce thermal resistance. Although there is a trend, thinning the wall thickness of molded products has had the problem of reducing the heat cycle resistance of the package. On the other hand, automotive regulators, acoustic
BACKGROUND OF THE INVENTION Due to the shift to hybrid ICs for high voltage, high power, and high frequency devices such as output circuits and power supply circuits of video equipment, devices are being increasingly packed in high density. Due to the difference in dimensional changes due to heat between the ceramic substrate on which the device is mounted and the pan cage of the device, which is made of a molded resin molded product, there have been problems such as the ceramic substrate cracking and the mounted device coming off.

As a solution to this problem, in order to obtain a good epoxy resin composition with high thermal conductivity, a technique using silicon nitride as an inorganic filler has been proposed in Japanese Patent Application Laid-Open No. 2-346575.
It was stated in the publication. Using silicon nitride has high thermal conductivity and a low linear expansion coefficient, and the low linear expansion coefficient reduces stress, which greatly improves heat cycle performance, but mold wear is significant compared to a formulation containing only crystalline silica. It turned out that it had some drawbacks.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to provide an epoxy resin composition that has high thermal conductivity, excellent heat cycle properties, and less mold wear.

[Means to solve the problem]

The present invention has been made to solve the above problems, and is characterized by an inorganic filler having an average particle size of 10 to 40.
An epoxy resin composition containing μ-crystalline silica and silicon nitride having an average particle size of 101I11 or less.

A particularly preferred aspect of the crystalline silica is that the crystalline silica has a maximum shape factor of 2.2 or less and is close to spherical.

The present invention will be explained in detail below.

As the inorganic filler used in the present invention, it is necessary to limit the use of crystalline silica to those with an average particle size in the range of 10 to 40 μ-, and the use of silicon nitride to those with an average particle size of 10 μ- or less. . In this way, by limiting the average particle diameter of the two types of inorganic fillers to the above range, the molded product can easily have a close-packed structure, and the inorganic filler has an order of magnitude better thermal conductivity than the binder resin. This is because the distance between adjacent materials is shortened and high thermal conductivity can be ensured. Therefore, 1
If silicon nitride with a particle diameter exceeding 0 μ- is used, it becomes difficult to form a close-packed structure, making it impossible to obtain high thermal conductivity. Furthermore, if the average particle size of crystalline silica is less than 10 μ-, the viscosity during melting will be high, the moldability will be poor, and filling defects will easily occur, whereas if the average particle size exceeds 40 tl #1, This is because the molding material may clog the gate of the mold.

The shape factor of crystalline silica refers to the ratio of the long axis to the short axis when one filler is viewed as a substantially elliptical shape, and is 1
represents spherical shape. Crystalline silica having a shape factor of more than 2.2 is undesirable because it moves away from a spherical shape and becomes sword-shaped, resulting in more significant mold wear.

In addition to the crystalline silica and silicon nitride, powders of fused silica, talc, alumina, rhusium silicate, rhusium carbonate, aluminum hydroxide, clay, and the like can be used as the inorganic filler.

As the epoxy resin, conventionally known epoxy resins can be used as appropriate. As such an epoxy resin, a compound having at least two or more epoxy groups in its molecule is preferable, and there are no particular restrictions on molecular structure or molecular weight, and examples include phenol novolac type epoxy resin, Talezol novolac type epoxy resin, etc. resin, bisphenol A type epoxy resin, or these halogenated epoxy resins.

As the crosslinking agent, phenol resin, melamine resin, acrylic resin, isocyanate resin, etc. can be used. In particular, as the phenol resin, phenol novolac resin, talesol novolac resin, resol resin, etc. can be mentioned. Among them, for example, 1 A phenolic resin with two or more hydroxyl groups in the molecule, with a hydroxyl equivalent of 80 to 1.
20. Those having a softening point of 60 to 120°C can be used alone or in combination with others.

The curing agent is not particularly limited, and amine curing agents such as aliphatic polyamines, polyamide resins, and aromatic diamines, acid anhydride curing agents, Lewis acid complex compounds, and the like can be used.

The curing accelerator is not particularly limited, and phosphorus-based and/or tertiary amine-based curing accelerators can be used.

In addition to the above-mentioned components of the epoxy resin composition of the present invention, commonly used release agents, coloring agents, coupling agents, etc. may be added as necessary. I can do it.

In addition, in order to make an epoxy resin composition from the above-mentioned ingredients, it is possible to uniformly mix the ingredients and manufacture it using the usual process of heating and melting, cooling, and pulverizing, and the equipment used at this time is also Those normally used can be applied as they are.

Next, the present invention will be specifically explained using Examples and Comparative Examples.

[Example] Regarding the compounding components of Examples 1 to 4 and Comparative Example 1.2, the inorganic filler was changed in the average particle size and shape factor of crystalline silica and silicon nitride in the formulation column in the upper row of Table 1. What was shown,
The other ingredients listed below were used in their respective amounts.

The epoxy resin has an epoxy equivalent of 200 and a softening point of 8.
14 parts by weight of ortho-cresol novolane epoxy resin at 0°C, and 14 parts by weight of phenol resin with a hydroxyl equivalent of 1
05, 7 parts by weight of phenol novolac resin with a softening point of 100°C, 2 methylimidazole as a curing accelerator
．． 1 part by weight, 5 parts by weight of carbon blank as a coloring agent, 0.5 parts by weight of epoxy silane as a coupling agent, 0.4 parts by weight of carnauba binder as a mold release agent, and silicone powder as a flexibilizing agent. 3 parts by weight of each was used.

In each of the above Examples and Comparative Examples, the surfaces of crystalline silica and silicon nitride were treated with a coupling agent, epoxysolane, and the above ingredients were uniformly mixed and dispersed for 3 minutes with a mixer, and then the roll temperature was set at 100 to 120 degrees. The mixture was heated, melted, and kneaded using a C mixing roll. This kneaded material is cooled,
Each epoxy resin composition was obtained by pulverization.

Physical properties such as linear expansion coefficient and thermal conductivity were measured using each test piece molded using a transfer molding machine using each epoxy resin composition obtained above, and the results are shown in the evaluation column of Table 1. Ta. Note that the linear expansion coefficient was measured by the duratometer method. Thermal conductivity was measured by the normal wire method using a quick thermal conductivity needle QTM-D2 manufactured by Showa Denko.
A 0 mm disc molded product was used.

In addition, using each of the epoxy resin compositions obtained above, a 40-cavity mold for 160IP molded products was attached to a transfer molding machine, and a 16DIP mold with a built-in silicon chip for evaluation of heat cycle properties with a size of 14 x 3.2 wm was installed. A molded article was molded at a mold temperature of 180° C. and a molding time of 60 seconds. This 161) IP molded product was heated to -65°C for 30 minutes and 15 minutes.
2 heat cycles with each cycle being 30 minutes at 0°C.
After 00 cycles, check the occurrence of pan cage crank by 3
The specimens were inspected using a 0x microscope and their number was determined. The results are shown in the evaluation column of Table 1 as the heat cycle failure rate.

The amount of mold wear was evaluated using the SE old method (SEMI G31: Se
m1conductor equipment an
d Materials International
5 standards), 900 d of each of the above epoxy resin compositions was preheated to 95°C, and
From an aluminum orifice at 0°C, 70kg/
It was extruded at an extrusion pressure of cd, and the weight loss of the orifice after extrusion was measured as the amount of mold wear. The orifice used had a nozzle diameter of 1.5 m and a length of 6.4 m.

The results are shown in the evaluation in Table 1 as the amount of mold wear.

From the evaluation results in the lower row of Table 1, Examples 1 to 4 are compared to Comparative Example 1.
It was confirmed that compared to No. 2, the thermal conductivity and coefficient of linear expansion were maintained, the heat cycle performance was excellent, and the amount of mold wear could be significantly reduced.

〔Effect of the invention〕

The novel epoxy resin composition of the present invention makes it possible to obtain an epoxy resin composition that has high thermal conductivity, excellent heat cycle properties, and less mold wear.

■ hand Continued Display of incidents 1990 Written amendment (voluntary) April 1991 Patent application No. 212729 address Name representative

Claims (2)

[Claims] (1) An epoxy resin composition comprising crystalline silica having an average particle size of 10 to 40 μm and silicon nitride having an average particle size of 10 μm or less as an inorganic filler. (2) The epoxy resin composition according to claim 1, wherein the crystalline silica has a maximum shape factor of 2.2 or less.