Copper foil for printed circuits
US5552234A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 24, 1994 |
| Grant date | Sep 3, 1996 |
| Priority date | — |
| Expiry date | Mar 24, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1291
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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 th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.