US Patent 7572351 Process for producing wiring circuit board

The invention provides a process for producing a wiring circuit board, which comprises the steps of: (A) forming a conductor layer of a predetermined pattern on an insulating layer; (B) forming a photosensitive solder resist layer on the insulating layer and the patterned conductor layer formed on the insulating layer; (C) disposing a transparent protective film on the photosensitive solder resist layer; and (D) exposing the photosensitive solder resist layer to a light through the transparent protective film.