Dry film photoresist for forming a conformable mask and method of application to a printed circuit board or the like
US5213945A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1991 |
| Grant date | May 25, 1993 |
| Priority date | — |
| Expiry date | Jul 25, 2011 |
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.