Patent ID: 6893576

Claim:
A method of manufacturing a multi-layer printed wiring board comprising an internal layer circuit forming step, an outer layer circuit forming step, and a solder resist forming step, wherein the inertial layer circuit forming step and the outer layer circuit forming step comprise steps of: providing a board coated with a patterning material; coating the surface of the patterning material with a photosensitive film; exposing the photosensitive film according to a predetermined conductive pattern; forming an etching resist by removing a portion of the photosensitive film which is not exposed from the board; removing the patterning material from the board according to the etching resist; and removing the etching resist from the board, and the solder resist forming step comprises steps of: coating the surface of the board subjected to the outer layer circuit forming step with a photosensitive solder resist material; coating the solder resist material with a photosensitive film; irradiating a laser beam on the photosensitive film according to a formed pattern of the solder resist, to form a light shielding mask having an exposed portion that absorbs an ultraviolet ray and an unexposed portion that does not absorb the ultraviolet ray; exposing the solder resist material to an ultraviolet ray through the unexposed portion of the light shielding mask; removing the light shielding mask; and removing the solder resist material which is not exposed due to the light shielding mask.