| 摘要 |
PURPOSE:To prevent irregular reflection from the surface of a circuit board when the board is irradiated with ultraviolet rays, by forming a coat film of an adhesive incorporated with an ultraviolet-ray absorbing agent on the surface of a substrate and laminating a photosensitive film on the adhesive layer. CONSTITUTION:An adhesive containing a metal plating catalyst is incorporated with an ultraviolet-ray absorbing agent and the adhesive is applied on an insulating substrate. A photopolymerizing resin film is laminated on the opposite sides of the substrate to provide photosensitive coat films. A negative film is disposed on the coat film so that it is exposed to ultraviolet rays and then the film is developed. The resulting substrate is further subjected to postexposure and to postheating so that a plating resist layer is formed. The substrate is then dipped in an electroless plating solution know in the art to form a conducting copper circuit. A pigment having high ultraviolet-ray absorbing properties may be added in the ultraviolet-ray absorbing agent. In this manner, a printed wiring board having fine patterns with a light width as small as 50mum can be produced and, further, little copper foil is deposited on the plating resist by the electroless plating. Accordingly, the wiring board is allowed to have improve insulating properties. |
