Method of forming a conformable mask on a printed circuit board
US4889790A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 1988 |
| Grant date | Dec 26, 1989 |
| Priority date | — |
| Expiry date | Feb 26, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/1105
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A dry film for forming a solder mask includes a cover sheet, a photoimageable composition layer which is curable to form a solder mask and a top coat interposed between the cover sheet and the photoimageable composition layer which is selectively adherent to the photoimageable composition layer. The dry film is applied to a surface of a printed circuit board with a minor portion of the area of the photoimageable composition layer tacked to the printed circuit board. The cover sheet is peeled away. With heat and vacuum, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, conforming the photoimageable composition layer to the contours thereof and leaving the top coat as a protective covering over the photoimageable composition layer. The photoimageable composition layer is exposed to patterned actinic radiation, developed and cured to form a hard, permanent solder mask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.