Printed circuit board with a uniform conductive layer formed by equalization of metals therein
US5023407A · kind A · utility
3Cited by
9References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1989 |
| Grant date | Jun 11, 1991 |
| Priority date | — |
| Expiry date | Aug 7, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/107
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A metal layer other than gold is formed on a ceramic substrate, a gold layer is further formed on said metal layer, and then a high density beam is applied to the treated substrate member. Thereby, the metal of the underlayer diffused through the grain boundaries of gold up to the surface of the gold layer by heat treatment or the like is uniformly mixed with gold to form an alloyed layer excellent in wettability to a solder. At the same time, nonmetallic impurities such as carbon adhering onto the surface of the gold layer are melted and removed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.