| 摘要 |
PURPOSE:To increase an alignment accuracy of a solder resist and to prevent the resist from hanging in a small-diameter via-hole prior to a plating process by irradiating ultraviolet rays onto a surface opposite to a surface on which an ultraviolet-ray cured plating and soldering resist is applied. CONSTITUTION:An ultraviolet-ray cured plating and solder resist film 5 is applied to the whole surface of one face of a printed wiring board. A through- hole portion is masked from the other face of the board. Then, ultraviolet rays is irradiated from the masked face and an uncured portion of the resist film 5 is removed by using a solvent such as a chlorothane. In the same manner, the resist film 5 is formed on a face opposite to the face on which the resist film is formed and a thick copper plating film 8 is formed on a conductive portion not coated with the resist film 5. Then, a thermosetting solder resist is applied to the whole surface. By this method, a very accurate resist can be formed. Therefore, the resist hanging in the through-hole before a thick chemical copper plating process is prevented from remaining and a high reliability can be achieved. |
