JPS605551B2 - Manufacturing method for highly thermally conductive ceramics - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing highly thermally conductive ceramics,
More specifically, the present invention relates to a method for producing ceramics that have excellent heat dissipation properties, are delicate, and have excellent electrical insulation properties.

[Technical background of the invention and its problems]

In the field of electronic equipment and energy-related electronic equipment, as the density thereof increases, for example, the integration of ICs and VLSIs progresses, there is a strong desire for the development of insulating materials with excellent heat dissipation properties.

Currently, various types of ceramics are used as such insulating materials.
has become the mainstream.

&0 is also used, and in some cases SiO, BN, A
IN is also beginning to be used. However, AI2Q has a limited thermal conductivity (maximum oK of about 30 W') and cannot sufficiently enhance its heat dissipation properties, and since AI2Q is a toxic substance, its use is not preferable.

In the case of BN, hexagonal crystals have low strength, and cubic crystals are as expensive as diamonds, so they are not commonly used and are not suitable for industrial use. In addition, AIN's theoretically have high thermal conductivity, but in reality, impurities (such as oxygen or trace amounts of Si) are unavoidable, and as a result,
A! It only shows a value about 2 to 3 times that of 203. Furthermore, although SIC is also a material with high thermal conductivity, it usually has low electrical resistance and is not suitable as an insulating material.
○-based materials were developed (Special Seki No. 56-66086, No. 57)
2591, No. 57-15484, etc.), but because this material has varistor properties, it cannot be used under high voltage.Moreover, it is inconvenient because the manufacturing process uses toxic substances. As described above, each of the conventionally known highly thermally conductive ceramics has its advantages and disadvantages, so there is a desire for a material that has even better heat dissipation properties and is highly electrically insulating.

[Purpose of the invention]

The present invention can meet the above industrial demands,
The purpose is to provide a method for manufacturing ceramics with excellent heat dissipation properties and electrical insulation properties.

[Summary of the invention]

The present invention is a method for manufacturing ceramics based on SIC-AIN.

That is, the method of the present invention comprises 0 to 85% by weight (excluding 0%) of silicon carbide powder and at least one oxide selected from the group of calcium oxide, barium oxide, and strontium oxide or thermally decomposed powder. A mixed powder consisting of 0.1 to 5% by weight of powder of at least one compound that is converted into each of the oxides and the balance is aluminum nitride powder is formed, and the obtained molded body is heated to 1600 to 1820% by weight.
It is characterized by being sintered at a temperature of 0.00. The mixed powder according to the present invention always contains SIC as a blended component, and its blending ratio is 85% or less (
However, 0 is not included. ) is set. Preferably,
It is 65% by weight or less. SIC blending ratio is 85% by weight
If this value is exceeded, the electrical insulation properties of the ceramics obtained by competitive bonding will deteriorate, thereby defeating the purpose. The particle size of the SIC powder used is usually about 2 Buddha's size or less. In addition, the mixed powder includes a powder of one or more oxides of Ca○, BaO, Sr○, or a compound that is thermally decomposed at the temperature during brazing and converted into the above-mentioned oxide, For example, for Ca0, CaC
03, CaN03; Regarding 0, BaC03, BaN
Regarding 03; SrN03, powders such as 03 and SrN03 are blended with S.

These powders are setting aids. The blending ratio is 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the total weight. If it is less than 0.1% by weight, the effect as a bran binder will not be exhibited, and if it is less than 0.1% by weight, %, the effect as a dawn coagulation aid not only reaches a saturated state and becomes meaningless;
On the contrary, the thermal conductivity of the resulting ceramics deteriorates due to late setting, which is disadvantageous. NN constitutes the remainder of the mixed powder.

The particle size of the MN powder used may normally be 0.2 to 2 degrees.
The mixed powder is prepared by putting the powders of the above-mentioned ingredients into a grinding mixer such as a ball mill, and mixing them for a predetermined period of time. This mixed powder is then filled into a predetermined mold and press-molded by a conventional method to form a molded body.

At this time, if an organic binder such as paraffin or stearic acid is added to the mixed powder in an amount of about 5 to 1% by weight (varies somewhat depending on the type of binder and the molding method), the molding operation can be carried out smoothly. This molded body is sintered to form the ceramic of the present invention.

Prior to compaction, the compact is heated, for example, in nitrogen gas for about 450 min.
The binder component can be removed by freezing at a temperature of °C. The atmosphere at the time of bidding may be any non-oxidizing atmosphere that does not react with SIC's AIN, and is usually an argon gas atmosphere.

As a competitive binding method, a hot press method is usually applied, for example, in which a molded body is placed in a carbon mold and then heated and pressed. A hot isostatic method can also be applied, and in this case, homogeneous and complex shapes can also be manufactured. In these cases the pressure is usually 100-3000k9/
It's a good thing. Furthermore, scaling of a molded article containing a large proportion of NN can also be carried out under normal pressure. In the method of the present invention, the silk temperature in this sintering process is 1600 to 1
It is necessary to set the temperature to 820 qo.

When the temperature is less than 1,600 oo, it is difficult to make the ceramic densified, resulting in problems in properties such as strength and thermal conductivity, and when the temperature exceeds 182,000, the thermal conductivity of the obtained ceramic decreases rapidly. Resulting in. [Examples of the invention] Example 1 Average particle size: 0. Physical O-type SIC powder 60mm and average particle size 1
．． Kano's AIN powder 389 and two quantities of high purity CaC03 powder (reagent grade) were weighed, placed in a ball mill pot, and thoroughly mixed.

Powfin was dispersed in the obtained mixed powder (approximately 7% by weight), and this was filled into a mold on the 37 x 37 x 100 side and press-molded at a pressure of 500 k9' to form a compact. did. This molded body was subjected to temporary molding at a temperature of 45,000 in a nitrogen stream. Next, this was set in a carbon mold and hot pressed in an argon gas flow for 3 minutes under the conditions of 1800 qo and 300 k9' flow.

The electrical resistance of the obtained composite body is greater than 1.60V under the condition of 10V, and the thermal conductivity is 100W/20K.
Met.

Examples 2 to 12 According to Example 1, 18-fold complexes were produced by changing the blended components, blending ratio, and adjacent stripe conditions as shown in the table.

The density, thermal conductivity, and electrical resistance of these were measured and the results are also listed in the table. [Effects of the Invention] As is clear from the above description, the method of the present invention is capable of producing a ceramic material that is delicate, has high electrical resistance, is rich in insulation, has high thermal conductivity, and has excellent heat dissipation properties. Therefore, its industrial value is great.

Claims (1)

[Scope of Claims] 1. 0 to 85% by weight (excluding 0) of silicon carbide powder and at least one oxide or thermally decomposed material selected from the group of calcium oxide, barium oxide, and strontium oxide. A mixed powder consisting of 0.1 to 5% by weight of powder of at least one compound that is converted into each of the oxides and the balance being aluminum nitride powder is molded, and the resulting molded body is heated to 1600 to 1820% by weight. A method for producing highly thermally conductive ceramics characterized by sintering in a temperature range of °C. 2. The method for producing highly thermally conductive ceramics according to claim 1, wherein the amount of the oxide powder or the compound powder is 0.5 to 3% by weight. 3. The method for producing highly thermally conductive ceramics according to claim 1, wherein the sintering is performed by a hot press method. 4 The sintering is performed using a hot isostatic press (HIP).
) A method for producing highly thermally conductive ceramics according to claim 1 or 3, which is carried out by the method. 5. The method for producing highly thermally conductive ceramics according to claim 1, wherein the sintering is performed under normal pressure.