Cleaning of Boards After the Application of a Solder Mask
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
In the manufacture of printed circuit boards a photosensitive solder mask is applied to the surface of the boards prior to passing the boards through a solder operation. One such commercially available solder mask is VACREL*. Photosensitive solder masks are exposed and developed after they are applied. The areas of the board which are exposed by the developing operation must be cleaned prior to the soldering operation. It has been found that the following sequence of steps results in a high degree of reliability from the solder operation: a. vapor blast b. chemical clean c. repeat vapor blast with board rotated 180 degrees It is noted that the vapor blast operation roughens the surface of the photosensitive dielectric, thereby enhancing and facilitating outgassing from the photosensitive dielectric.