JPS5958847A - Substrate for electric insulation and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the insulating substrate without requiring a high-temperature high-pressure press and sintering by adding and mixing a fixed quantity of an organic polymerization agent to aluminum nitride powder. CONSTITUTION:A material, thermal conductivity thereof is lower than aluminum nitride and a thermal expansion coefficient and electric resistivity thereof are larger than that, such as unsaturated polyester is selected as the organic polymerization agent, and a proper quantity of benzoyl peroxide, etc. are added to the material as a high-temperature curing agent. The polymerization agent is kneaded with aluminum nitride by approximately 2-7% wt., and hot-pressed at a comparatively low temperature of 100-400 deg.C and completed. Curing capability degrades when the polymerization agent is 2% wt. or less, and thermal conductivity and the thermal expansion coefficient degrade when it is 7% wt. or more. According to the constitution, the substrate of not less than 10<9>OMEGAcm resistivity, not less than 0.05cal/cm sec deg.C thermal conductivity and a not more than 6X10<-6>/ deg.C expansion coefficient is obtained easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrically insulating substrate mainly made of aluminum nitride and a method for manufacturing the same.

2. Description of the Related Art With the development of the semiconductor industry in recent years, insulating substrates used for integrated circuits and the like are becoming more densely packed with semiconductor chips, and materials with better heat dissipation properties are required. In other words, such an insulating substrate has high electrical insulation and thermal conductivity, and a coefficient of thermal expansion equivalent to that of silicon.
It is also necessary to have high mechanical strength.

However, aluminum nitride material has attracted attention as a material that satisfies these requirements14, namely, its thermal conductivity is 0.1 at room temperature.
is~0. 16 c&L/cI! L.

see °C, which is approximately twice that of alumina,
Furthermore, it has superior high temperature resistance compared to other ceramics, and its coefficient of thermal expansion is 6 compared to alumina's approximately 8X10/℃.
It has a low X10/'C or less, good thermal shock resistance, and the electrical resistivity of aluminum nitride is 10 Ω.
α or more, the electrical insulation and dielectric properties are particularly excellent in the high frequency range, and the dielectric loss tangent is extremely small.

Aluminum nitride such as C is prepared depending on its use, for example, by molding aluminum nitride powder into a desired shape and sintering it in an atmosphere to form a sintered body. However, since aluminum nitride is a compound that is inherently difficult to sinter, high-density ivy with high thermal conductivity (1500
-2000'0, high temperature of 100 atmospheres or more, and pressure sintering such as hot pressing with high pressure is required. Moreover, even in such a high-temperature, high-pressure sintering method, it is necessary to add a sintering promoting JEM agent such as manganese oxide or strontium oxide in order to obtain a monolithic body with higher density. However, such small machining is not preferable because it often causes the inherent excellent thermal conductivity of aluminum nitride to become larger than 4H.

The present invention aims to provide an electrically insulating substrate based on aluminum nitride that is different from these conventional methods, and a method for manufacturing the same. and its manufacturing method. 1 (Ii) According to the present invention, an organic polymerizing agent having an imaginary coefficient of 2 to 7 is added to and mixed with aluminum nitride powder consisting of particles of approximately 5μ, and the mixture is heated at a relatively low temperature of 100 to 400°C. This is achieved by hot pressing under the

The organic polymerization agent added as described above generally has a lower thermal conductivity than aluminum nitride, and one with a large coefficient of thermal expansion and electrical resistivity is recommended, such as unsaturated polyester, alkyd, etc. Or with Evokin etc.
Adding appropriate amounts of high-temperature curing agents such as benzoyl peroxide (BPO), t-butylperoxo-2-ethylhexanoate (TBPO), dichloroperoxide (DCP), and lauroyl peroxide (LP) to these can be effectively used. It will be done.

For example, the thermal conductivity of a single polymer made by adding 1 weight - 1% of DCP to alkyd is 0.025 catm, sec, °C, the thermal expansion is 25 x 107 °C, and the electrical resistivity is 10
Qcm.

The present invention uses such an organic polymerization agent for aluminum nitride,
It is used in the range of 2.0 to 7.0 weight ratio, but 2
．． If it is less than 0% by weight, the thermosetting property is poor, and if it is less than 7.0% by weight.
In the above case, the apparent porosity decreases and the density increases, but the thermal conductivity and the coefficient of thermal expansion each deviate from the predetermined ranges.

The aluminum nitride and the organic polymerization agent must be heated as uniformly as possible, and mixing and kneading using a grinder or the like is preferred, for example. In some cases, it is also effective to microcapsule aluminum nitride with a combination agent.

As described above, the present invention provides an electrically insulating substrate mainly made of aluminum nitride using an extremely simple method.
Its industrial value is said to be extremely large.

The present invention will now be explained in more detail by way of practical examples.

Example 41 A polymerization agent was prepared by adding and mixing 0.5 part of dichloroperoxide (DCP) as a hardening agent to 100 parts of unsaturated alkyd (manufactured by Asahibe Co., Ltd.). Next, the particle size is 3~5μ
To 100 parts by weight of aluminum, the above-mentioned organic polymerizing agent was added in varying amounts in the range of 1 to 10 parts by weight, mixed for 30 minutes in a crusher, and then heated to a temperature of 100 to 300°C.
, pressure 100-400 Kg/CJ, degree of vacuum I x 1
A disk-shaped substrate having a thickness of approximately 28IllIIIφ×1 was fabricated under the condition of hot pressure molding in a +ia range of 0-2 to 10-” Torr and a curing time of 20 minutes.

The physical properties of the obtained substrate are shown in Table 1 below.
As is clear from the table, experiment number A is within the scope of the present invention.
It can be seen that physical properties such as thermal conductivity, coefficient of thermal expansion, and electrical resistivity in Examples 4 to A6 and AI 1 to A15 are all excellent.

Example 10 parts by weight of acetone are added to 1 part by weight of a polyester resin having a particle size of 1μ or less (manufactured by Sumitomo Chemical Co., Ltd., trade name Kokoru) in a closed container, and stirred for 48 hours to prepare a solution. 100 parts by weight of aluminum nitride having a particle diameter of 3 to 5 microns was added, mixed by stirring for 30 minutes using a pickling machine, and then dried at a temperature of 40 to 60°C. Next, the molded body was weighed so that it had a disc shape of approximately 28mm diameter x 1mm thick, and the temperature was 100 to 300°C, the pressure was 100 to 400°C, and the pressure was 97cm, and the degree of vacuum was I x 10.
The substrate was manufactured under conditions of hot pressure molding in the range of ~lXl0 Torr and a cure time of 20 minutes. Table 2 shows the physical properties of the obtained substrate. That is, as is clear from Table 2, the physical properties of the thermal conductivity, thermal expansion coefficient, and electrical resistivity of the experimental numbers 3 to 6 and AI 1 to A 15, which are within the scope of the present invention, are excellent. It can be seen that

Claims (1)

[Claims] (1) Contains an organic polymerization agent mainly composed of aluminum nitride, has an electrical resistivity of 10 Ωα or more, and a thermal conductivity of 0.0.
5caL/cm, sec℃ or more, thermal expansion coefficient is 6×
An electrically insulating substrate characterized by a temperature of 1O/°C or less. (2) A method for producing an electrically insulating substrate, which comprises adding 2 to 7 parts by weight of an organic polymerization agent to aluminum nitride powder and hot pressing at 400°C or lower.