Patent ID: 7988842

Claim:
A continuous copper electroplating method wherein a workpiece to be placed is continuously electroplated in a plating vessel accommodating a copper sulfate plating bath containing an organic additive by use of a soluble or insoluble anode as an anode and the workpiece as a cathode, the method comprising the steps of: providing an overflow vessel for accommodating a plating bath overflowing from said plating vessel adjacent to said plating vessel, returning the plating bath in said overflow vessel to said plating vessel while permitting the plating bath from said plating vessel to overflow into said overflow vessel, providing an oxidative decomposition vessel different from said plating vessel, transferring the plating bath to said oxidative decomposition vessel, and returning the plating bath from said oxidative decomposition vessel through said overflow vessel to said plating vessel for circulating the plating bath between said plating vessel and said oxidative decomposition vessel; and metallic copper is immersed in said oxidative decomposition vessel and exposed to air bubbling, so that while said metallic copper is dissolved in the form of copper ions in said oxidative decomposition vessel; decomposed organic products and/or degenerated organic products formed by decomposition or degeneration of said organic additive in the course of the copper electroplating are subjected to oxidative decomposition treatment on surfaces of said metallic copper by non-electrolytic oxidation action independent from a current applied between said anode and said cathode, wherein said overflow vessel comprises first and second overflow vessels through which the plating baths are mutually movable, under which the plating bath is returned from the first overflow vessel to said plating vessel and the plating bath is introduced from said second overflow vessel into said oxidative decomposition vessel to subject the plating bath to oxidative decomposition treatment, and the plating bath after the oxidative decomposition treatment is introduced from said oxidative decomposition vessel into the first overflow vessel for circulating the plating bath between said plating vessel and said oxidative decomposition vessel.