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:
Mar. 17, 1992
Filed:
Feb. 05, 1990
Yoshirou Kuromitsu, Saitama, JP;
Hideaki Yoshida, Saitama, JP;
Toshiyuki Nagase, Saitama, JP;
Hiroto Uchida, Saitama, JP;
Tadaharu Tanaka, Saitama, JP;
Yoshio Kanda, Saitama, JP;
Kenji Morinaga, Fukuoka, JP;
Mitsubishi Metal Corporation, Tokyo, JP;
Abstract
An insulating substrate is used for fabrication of a thick film circuit and comprises a foundation of aluminum nitride and a surface film structure provided on the foundation, in which the foundation contains at least one oxidizing agent selected from the group consisting of an yttrium oxide and a calcium oxide ranging from 0.1% to 10% by weight for enhancing a stiffness of the foundation, and in which the surface film structure is of the multi-level surface film structure having a lower surface film of an aluminum oxide rapidly grown on the foundation in the presence of the oxidizing agent and an upper surface film containing a silicon oxide and a substance selected from the group consisting of a zirconium oxide, a titanium oxide and a boron oxide for enhancing the resistivity against a firing operation.