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:
Dec. 07, 1999
Filed:
Nov. 14, 1997
Kazuo Ikeda, Yokohama, JP;
Hiroshi Komorita, Yokohama, JP;
Yoshitoshi Sato, Yokohama, JP;
Michiyasu Komatsu, Yokohama, JP;
Nobuyuki Mizunoya, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
This invention provides a silicon nitride circuit board in which a metal circuit plate is bonded to a high thermal conductive silicon nitride substrate having a thermal conductivity of not less than 60 W/m K, wherein a thickness D.sub.s of the high thermal conductive silicon nitride substrate and a thickness D.sub.M of the metal circuit plate satisfy a relational formula D.sub.s .ltoreq.2D.sub.M. The silicon nitride circuit board is characterized in that, when a load acts on the central portion of the circuit board which is held at a support interval of 50 mm, a maximum deflection is not less than 0.6 mm until the silicon nitride substrate is broken. The silicon nitride circuit board is characterized in that, when an anti-breaking test is performed to the circuit board which is held at a support interval of 50 mm, an anti-breaking strength is not less than 500 MPa. The metal circuit plate or a circuit layer are integrally bonded on the silicon nitride substrate by a direct bonding method, an active metal brazing method, or an metalize method. According to the silicon nitride circuit board with the above arrangement, high thermal conductivity and excellent heat radiation characteristics can be obtained, and heat cycle resistance characteristics can be considerably improved.