| 摘要 |
PURPOSE:To obtain a silver plating film having no steps at all times by subjecting a metallic material to a cathodic electrolyzing treatment after strike plating then subjecting the island parts and the tip parts of inner lead thereof to partial silver plating followed by a stripping treatment. CONSTITUTION:A lead frame for an IC is subjected to strike plating then to a cathodic electrolyzing treatment to reduce the oxide film formed in the peripheral part of the lead frame to the surface of the metallic simple subtance. An object to be treated is installed as the cathode and an insoluble electrode (carbon, stainless steel, etc.) as the anode in the cathodic electrolyzing treatment. An aq. soln. of sodium chloride, sodium hydroxide, etc. is used for the electrolyte. The island parts and the tip parts of inner lead are subjected to partial silver plating and then to the cathodic electrolyzing treatment according to need to strip the plating.
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