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:
Jan. 28, 1997
Filed:
Nov. 09, 1995
Sumitomo Metal Ceramics, Inc., Mine, JP;
Abstract
A ceramic circuit board comprises a ceramic substrate having a glaze film formed thereon, the glaze film being overlaid with a functional thin film such as a ferromagnetic film serving as a magnetic sensor, for example. The ceramic substrate is made of a low-firing ceramic material such as a glass ceramic material which can be sintered at a temperature below 1000.degree. C. by co-firing with the glaze film. Preferably, the ceramic substrate has a recess on its top surface, and the glaze film is embedded in the recess such that the difference in level between the ceramic substrate and the glaze film is 20 .mu.m or less. The ceramic circuit board can be produced by preparing a plurality of ceramic green sheets from a low-firing ceramic material, laminating the ceramic green sheets after a through-hole or indentation is formed in the uppermost sheet, thereby forming a multilayer ceramic green substrate having a recess on its top surface, filling the recess with a glaze-forming glass material to such a height that the difference in level between the ceramic substrate and the glaze film formed after firing is 20 .mu.m or less, and co-firing the ceramic green substrate and the glaze-forming glass material at a temperature below 1000.degree. C.