Process for whisker-free aqueous electroless tin plating
US6361823B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 1999 |
| Grant date | Mar 26, 2002 |
| Priority date | — |
| Expiry date | Dec 3, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12722
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A process of preserving solderability and inhibiting tin whisker growth of exposed copper or copper alloy surfaces on a substrate comprises the steps of preparing an immersion tin plating solution substantially free of other immersion-platable metals; applying the immersion tin plating solution to the substrate to form a tin coating on the surfaces; preparing an immersion alloy plating solution containing at least two immersion-platable metals; applying the immersion alloy plating solution to the substrate by immersing the substrate in the immersion alloy plating solution to form an alloy cap layer on the tin coating. The immersion platable metals in the immersion alloy plating solution may be at least two metals selected from tin, silver, bismuth, copper, nickel, lead, zinc, indium, palladium, platinum, gold, cadmium, ruthenium and cobalt. The immersion platable metals may be added to the solution in the form of metal salts
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.