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Summary:PURPOSE:To prevent a plating resist from separating or swelling so as to enable the formation of a fine pattern by a method wherein a pattern chemical copper plating is executed at a certain potential specified to that of a reference hydrogen electrode. CONSTITUTION:A second metal layer 3 is provided onto a copper layer 2 on an insulating board 1, which is masked with a plating resist 4 excluding a circuit forming part, and a pattern chemical copper plating 5 is carried out onto the required circuit forming part. The pattern chemical copper plating 5 is executed at a plating reaction potential higher than the potential of a reference hydrogen electrode by -550mV. After plating, an etching resist is formed through solder plating 6, then the plating resist 4 is removed, the parts of the second metal layer 3 and the copper layer 2 covered with the plating resist 4 are removed through etching, the solder plating layer 6 is removed, and the circuit pattern of a printed board is formed. By this setup, a plating resist can be prevented from separating or swelling, and a fine pattern can be formed.
Bibliography:Application Number: JP19890132615