ABSTRACT
There are two categories of circuit board coatings: bare-board coatings and assembly coatings [25]. Bare-board coatings, also called permanent solder masks, are applied during the board fabrication process as liquids or dry films over conductive finishes or bare copper, and are cured by either heat or ultraviolet (UV) light. The primary function of the solder mask is to ward off solder wetting, reducing the need for touch-up after machine soldering.
