Patent ID: 7892411

Claim:
An electrolytic copper plating process for electroplating copper on a plurality of workpieces in a copper sulfate plating bath containing copper sulfate and an organic additive therein in a vertical, continuous-conveyance plating tank wherein a plurality of soluble or insoluble anodes are used, and said workpieces are used as cathodes, comprising the steps of: immersing oxidative decomposition units including metal copper in an unpowered state in a region of said copper sulfate plating bath in said plating tank in which the anodes and the workpieces are immersed, said region being apart from a region between said anodes and said cathodes, such that a neighborhood of the thus-immersed metal copper is used as an oxidative decomposition region, wherein the anodes are arranged along a moving direction of the workpieces such that the anodes oppose front and rear sides of the workpieces, the oxidative decomposition units including said metal copper are arranged such that a part of the oxidative decomposition units is located lateral to one end of the anodes in a moving direction of the workpieces and the remainder of the oxidative decomposition units is located lateral to the opposite end of the anodes, said oxidative decomposition units are surrounded and isolated by anti-spreading means for air bubbles such that said copper sulfate bath is movable through said anti-spreading means for air bubbles, and said air bubbles are applied to said inside of said anti-spreading means for air bubbles; and shield plates are arranged between the oxidative decomposition units and the anodes so as to inhibit a bipolar phenomenon; setting a current density at not higher than 5 A/L; setting an immersed area of said metal copper at 0.001 to 1 dm 2 /L based on said plating bath; and applying air bubbling to said oxidative decomposition region at 0.01 to 2 L/dm 2 ·min based on said immersed area, whereby said electroplating is performed while dissolving said metal copper as copper ions and also while subjecting on a surface of said metal copper a decomposed/modified organic product, which has been formed as a result of decomposition or modification by an oxidation or reduction reaction of said organic additive, to oxidative decomposition by a non-electrolytic oxidizing action independent from a current impressed between said anodes and said cathodes.