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:
Jul. 20, 1993
Filed:
Sep. 03, 1991
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
A ceramic electrically insulating circuit board (1) has an electrically conductive plug (4a) tightly filling a through-hole (2) formed in the circuit board (1) made of aluminum nitride including a low, up to 1% by weight at the most, content of an oxide phase as a sintering assistant. The conductive plug is formed by putting high melting point metal paste (10) into the through-hole and sintering either the board prior to the metal paste or sintering both, the board and the paste, simultaneously. Then, causing melted copper or copper alloy (11) to permeate into gaps or interstices in the sintered high-melting point metal plug to form a tight seal of the hole and good electrical contacts of the conductive plug and any circuits on both sides of the board.