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:
Feb. 11, 1992
Filed:
May. 18, 1990
Yoshirou Kuromitsu, Saitama, JP;
Hideaki Yoshida, Saitama, JP;
Toshiyuki Nagase, Saitama, JP;
Tadaharu Tanaka, Saitama, JP;
Yoshio Kanda, Saitama, JP;
Mitsubishi Metal Corporation, Tokyo, JP;
Abstract
An insulating substrate is used for fabrication of a thick film circuit provided with a conductive pattern made from a paste containing glass frits, and comprises a foundation containing an aluminum nitride and incidental impurities, and a multi-level surface film structure provided between the foundation and the conductive pattern and having a lower surface film of an aluminum oxide provided on a surface of the foundation, an intermediate surface film provided on the lower surface film and formed of a substance having a relatively small acidity and an upper surface film provided on the intermediate surface film and formed of a substance having a relatively large acidity, in which the substance with the large acidity rapidly reacts with the frits in a firing stage for enhancing the adhesion of the conductive pattern but the substance with the relatively small acidity restricts the consumption thereof, so that the total thickness of the multi-level film structure is decrased and, accordingly, the heat radiation capability is improved.