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:
Dec. 31, 1991
Filed:
Sep. 06, 1989
Applicant:
Inventors:
Yasuo Tanaka, Tokyo, JP;
Naohito Yoshimura, Tokyo, JP;
Koichi Nakano, Tokyo, JP;
Touru Nohtomi, Tokyo, JP;
Morio Gaku, Tokyo, JP;
Assignee:
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05K / ;
U.S. Cl.
CPC ...
148269 ; 148272 ; 427 97 ;
Abstract
A process for producing a multilayer printed wiring board, characterized in that copper surface of internal layer(s) is chemically oxidized, thereby forming a brown or black, oxidized copper surface on the internal layer board; and said oxidized copper surface of said internal layer board is treated with an acidic aqueous solution of a reducing agent containing at least one material selected from the group consisting of zinc formaldehyde sulfoxylate and sodium hypophosphite.