Post-etch, printed circuit board cleaning process
US5411595A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 1993 |
| Grant date | May 2, 1995 |
| Priority date | — |
| Expiry date | Jul 13, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/124
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A novel, environmentally innocuous, post-etch, pre-soldering cleaner and cleaning process is disclosed for removing contaminants from plated surfaces of printed circuit boards manufactured by the pattern plating method. The post-etch, cleaning process of this invention, for removing contaminants from plated surfaces of an etched printed circuit, comprises treating the plated surfaces with a cleaning solution which comprises an aqueous solution of (i) an imidazole-2-thione compound and (ii) an acid. The imidazole-2-thione compound has the formula: ##STR1## wherein A and B are the same or different --R--Y groups, wherein R is a linear, branched or cyclic alkenyl group containing 1 to 12 carbon atoms and Y is a hydrogen, halogen, cyano, vinyl, phenyl or ether moiety. Of this class of compounds, 1-methyl-3-propylimidazole-2-thione is preferred. The novel aqueous cleaners of this invention are effective replacements for conventional cleaners containing the toxic material thiourea and are superior to cleaners free of thiourea.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.