Bath and method for the electroless plating of tin and tin-lead alloy
US5266103A · kind A · utility
13Cited by
9References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 1, 1992 |
| Grant date | Nov 30, 1993 |
| Priority date | — |
| Expiry date | Jul 1, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K3/3473
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A tin or tin-lead alloy electroless plating bath comprising (A) a stannous salt or a mixture of a stannous salt and a lead salt, (B) an acid, (C) thiourea or a thiourea derivative, and (D) a reducing agent is improved by adding (E) a nonionic surfactant and optionally, (F) a cationic surfactant, a nitrogenous heterocyclic compound or a derivative thereof, or alternatively by adding (G) an ammonium or quaternary ammonium ion. From the bath, uniform films of fine grains will chemically deposit on fine pitch printed wiring boards intended for SMT.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.