| abstract |
A copper foil for fine wiring is produced by forming on a bonding surface of a copper foil a composite metal layer comprising (I) copper, (II) at least one of tungsten and molybdenum and (III) at least one of nickel, cobalt, iron and zinc by carrying out electrolysis in a plating bath (A) containing ions of these metals and chloronium ions, and then forming a roughened layer comprising copper on the composite metal layer by carrying out electrolysis in a plating bath (B) containing copper ions at a current density not lower than a limiting current density of the plating bath to form a dendritic copper electrodeposition layer and then carrying out subsequent electrolysis at a current density lower than the limiting current density of plating bath to form nodular copper. |