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:
Jun. 13, 2000
Filed:
May. 27, 1997
Yoshikazu Nakata, Kobe, JP;
Syozo Otomo, Asa-gun, JP;
Kazunari Tanaka, Mine, JP;
Koichi Uno, Nagoya, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Sumitomo Metal Ceramics Inc., Yamagushi, JP;
Abstract
A process for forming fine thick-film conductor patterns on a ceramic substrate which comprises the steps of forming grooves in a positive-working photoresist layer on the substrate by the photolithographic technology, filling the grooves with a conductive paste by squeezing with a squeegee, removing the photoresist layer by a wet process, and firing the remaining conductive paste pattern is improved. By the improvements, the conductive paste is squeezed into the grooves by the screen printing technique using a mask, and/or the solvent in the conducive paste consists essentially of one or more hydrocarbons, and/or the squeegee is made of a material having a flexural modulus in a range of 30-200 kgf/mm.sup.2. The formation of the grooves may be accomplished by laser beam machining; in this case a negative-working photoresist or any other soluble resin may be used to form the grooves therein. Also provided are a process for forming a fine thick-film conductor pattern by means of transfer of a conductive paste pattern formed on a support film to a green sheet, as well as a process for forming bumps on a ceramic circuit substrate.