The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 02, 2003
Filed:
Oct. 26, 2001
Michiyasu Komatsu, Yokohama, JP;
Haruhiko Yamaguchi, Yokohama, JP;
Takayuki Naba, Ibo-Gun, JP;
Hideki Yamaguchi, Yokosuka, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
The present invention provides a silicon nitride ceramic substrate composed of a silicon nitride sintered body in which maximum size of pore existing in grain boundary phase of the sintered body is 0.3 &mgr;m or less, and having a thermal conductivity of 50 W/mK or more and a three point bending strength of 500 MPa or more, wherein a leak current is 1000 nA or less when an alternative voltage of 1.5 kV-100 Hz is applied to a portion between front and back surfaces of the silicon nitride sintered body under conditions of a temperature of 25° C. and a relative humidity of 70%. According to the above structure of the present invention, there can be provided a silicon nitride ceramic substrate capable of effectively suppressing a leak current generation when the above substrate is assembled into various power modules and circuit boards, and capable of greatly improving insulating property and operative reliability of power modules in which output power and capacity are greatly increased.