Tin whisker-free printed circuit board
US6720499B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 2001 |
| Grant date | Apr 13, 2004 |
| Priority date | — |
| Expiry date | Jan 24, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12722
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A printed circuit board including electrical circuitry formed on an outer surface of the printed circuit board, the circuitry comprising copper or a copper alloy; a final finish on the circuitry, the final finish including a coating of tin on the copper or copper alloy circuitry; and an alloy cap layer on the tin coating, the alloy cap layer comprising at least two immersion-platable metals. The immersion platable metals in the alloy cap layer may be at least two metals selected from tin, silver, bismuth, copper, nickel, lead, zinc, indium, palladium, platinum, gold, cadmium, ruthenium and cobalt. The circuitry remains whisker free and solderable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.