LOW SURFACE ROUGHNESS ELECTROLYTIC COPPER FOIL AND PROCESS FOR PRODUCING THE SAME

摘要

A low surface roughness electrolytic copper foil having a surface roughness Rz not higher than 2.5 mum and an elongation percentage not smaller than 6% at 180°C in which tensile strength at 25°C measured within 20 min of the point in time of ending electrodeposition is not higher than 500 MPa and the lowering rate of tensile strength at 25° C measured within 300 min of the point in time of ending electrodeposition is not higher than 10%. The low surface roughness electrolytic copper foil is produced by a process employing aqueous solution of sulfuric acid-copper sulfate as electrolyte and conducting a DC current between an insoluble anode of titanium coated with a platinum metal element or its oxide element and a titanium cathode drum facing the anode, wherein the electrolyte contains hydroxyethyl cellulose, polyethylene imine, a sulfonate of active organic sulfur compound, acetylene glycol and chlorine ions.