Low surface roughness electrolytic copper foil and process for producing the same

摘要

An electrodeposited copper foil with low surface roughness having a surface roughness R_z 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 electrodeposited copper foil with low surface roughness 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 hydroxyethylcellulose, polyethyleneimine, a sulfonate of active organic sulfur compound, acetylene glycol and chlorine ions.