Method of application of a conforming mask to a printed circuit board
US5164284A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 19, 1991 |
| Grant date | Nov 17, 1992 |
| Priority date | — |
| Expiry date | Nov 19, 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 heat, vacuum and mechanical pressure, the photoimageable composition layer is laminated to the irregular surface of the printed circuit board, partially conforming the photoimageable composition layer to the contours thereof. Within about 60 seconds and with the photoimageable composition layer still heated, the cover sheet is peeled away, leaving the top coat as a protective covering over the photoimageable composition layer. Removal of the cover sheet allows the photoimageable composition layer to fully conform to the contours of the printed circuit board. Immediately thereafter, the circuit board is cooled to about ambient temperature or below. 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.