COPPER FOIL COATED WITH PURE COPPER AND PRODUCTION PROCESS THEREOF, AND TAB TAPE AND PRODUCTION PROCESS THEREOF

摘要

A copper foil which is substantially free of generation of voids even if fusing treatment is conducted on a tin-plated layer and which is excellent in etching properties is provided. To achieve this object, a pure copper-coated copper foil in which a pure-copper plated layer is formed at least on a gloss surface of a base copper foil is employed. The pure copper-plated layer preferably has a thickness of not less than 0.3 mum. A method of producing a pure copper-coated copper foil, in which electrolysis is conducted using, as an electrolyte, an aqueous sulfuric acid-copper sulfate solution having a ClSUP-/SUP ion concentration of not more than 0.5 mg/l with a base copper foil serving as a cathode, thereby forming a pure copper-plated layer at least on a gloss surface of the base copper foil. The aqueous sulfuric acid-copper sulfate solution preferably has a CuSUP2+/SUP ion concentration of 40 g/l to 120 g/l and a free SOSUB4/SUBSUP2-/SUP ion concentration of 100 g/l to 200 g/l.