Denki Kagaku Kogyo Kabushiki Kaisha

Takeshi Gotoh

Kohki Ichikawa

Hiroshi Murata

Motoharu Fukazawa

Katsunori Terano

Yoshitaka Taniguchi

Akira Miyai

Yusaku Harada

Isao Sugimoto

Yutaka Hirashima

Nobuyuki Yoshino

Tetsumi Ohtsuka

Yasuhito Hushii

Syoji Takakura

Yoshihiko Tujimura

Disclosed is an aluminum nitride substrate for a circuit board, the substrate having aluminum nitride crystal grains with an average grain size of 2 to 5 &#x3bc;m and a thermal conductivity of at least 170 W/m&#xb7;K. The aluminum nitride substrate does not include a dendritic grain boundary phase and has a breakdown voltage of at least 30 kV/mm at 400&#xb0; C. Also provided is a method for producing the aluminum nitride substrate, including the steps of heating a raw material containing an aluminum nitride powder to 1500&#xb0; C. at a pressure of at most 150 Pa, then increasing and holding the temperature at 1700 to 1900&#xb0; C. in a pressurized atmosphere of at least 0.4 MPa using a non-oxidizing gas, then cooling to 1600&#xb0; C. at a cooling rate of at most 10&#xb0; C./min.

Aluminum nitride substrate for circuit board and production method thereof

Provided are a process for producing a highly reliable ceramic sheet with stable quality by reducing voids, and a ceramic substrate using the sheet. A highly reliable ceramic sheet with stable quality is obtained by using hydroxypropylmethyl cellulose as an organic binder, kneading a powder material, preferably, with a twin screw extruder, and then forming a sheet by means of a single screw extruder equipped with a sheet die, and the sheet is suitably used for a ceramic substrate and a ceramic circuit board.

Method for producing ceramic sheet, ceramic substrate using ceramic sheet obtained by such method, and use thereof

Provided are a silicon nitride substrate and a silicon nitride circuit board with excellent electrical characteristics, and power control parts utilizing them. A silicon nitride substrate comprises a silicon nitride sintered body obtainable by sintering a silicon nitride powder in the presence of a sintering aid comprising MgO, YOand SiOin a proportion of (1) MgO/(MgO+SiO)=34-59 mol %, and (2) YO/(YO+SiO)=50-66 mol %, and a silicon nitride circuit board utilizes it.

Silicon nitride substrate, silicon nitride circuit board utilizing the same, and use thereof

The present invention relates to a process of producing an aluminum nitride sintered body which satisfies both high thermal conductivity and reduction in the shrinkage factor at the time of sintering. The aluminum nitride sintered body is a sintered body of a powder mixture containing an aluminum nitride powder and a sintering aid, characterized by having a thermal conductivity of at least 190 W/m&#xb7;K and a shrinkage factor represented by the percentage of {(dimensions of the molded body before sintering)&#x2212;(dimensions of the sintered body after sintering)}/(dimensions of the molded body before sintering) of at most 15%.

Process for producing aluminum nitride sintered compacts

To provide an aluminum nitride powder and an aluminum nitride sintered body which satisfy both high thermal conductivity of an aluminum nitride sintered body and reduction in the shrinkage factor at the time of sintering. An aluminum nitride powder characterized in that it has local maximum values in size in regions of from 3 to 15 &#x3bc;m, from 0.5 to 1.5 &#x3bc;m and 0.3 &#x3bc;m or less, the proportions of particles in the respective regions are from 40 to 70%, from 25 to 40% and from 0.5 to 20% on the volume basis, and it has an oxygen amount of from 0.5 to 1.5 mass %. An aluminum nitride sintered body which is a sintered body of a powder mixture containing the above aluminum nitride powder and a sintering aid, characterized by having a thermal conductivity of at least 190 W/m&#xb7;K and a shrinkage factor represented by the percentage of {(dimensions of the molded body before sintering)&#x2212;(dimensions of the sintered body after sintering)}/(dimensions of the molded body before sintering) of at most 15%.

Aluminum nitride powder and aluminum nitride sintered compact

A circuit substrate which has a ceramic substrate and an Al circuit comprising Al or an Al alloy bonded to said ceramic substrate via a layer comprising Al and Cu.

Growing community of inventors

Omuta, Japan

Takeshi Gotoh