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:
Sep. 03, 1996
Filed:
Mar. 24, 1994
Yoshio Kawasumi, Toda, JP;
Japan Energy Corporation, Tokyo, JP;
Abstract
A copper foil for printed circuits including a thermal oxidation-resistant treated layer (e.g., Zn--Ni or Zn--Co alloy plating) formed on the shiny side of the foil and a Cr-base anticorrosive treated layer (e.g., chromate film, mixed film of chromium oxide and zinc and/or zinc oxide, or both) formed further thereon, characterized in that a copper plating layer or an etched surface is provided before forming the thermal oxidation resistant treated layer. The copper plating or etching permits the shiny side to be completely covered with fresh copper or purified to overcome any ununiformity of the chemical activity and/or any lack of smoothness of the entire surface of the shiny side. The evenness of the freshly formed copper surface enhances the homogeneity and completeness of the thermal oxidation-resistant plated layer to be formed subsequently by thermal oxidation resistance treatment, rendering it possible to take the full advantage of the thermal oxidation-resistant treated layer. Thus a surface treatment technique of imparting a thermal oxidation resistance upon heating at 300.degree. C. for 30 minutes to the shiny side of copper foil has now been successfully developed for the first time in the art.