| 摘要 |
PURPOSE: Provided is a method of producing a copper foil for fine wiring, which has a bonding surface uniformly roughened to a low surface roughness, has good etching properties, enables high density fine wiring and also adheres strongly to base materials. CONSTITUTION: A method of producing a copper foil for fine wiring comprises the steps of treating a copper foil as a cathode by electrolysis in a plating bath (A) containing (i) copper ions, (ii) metal ions of at least one metal selected from the group consisting of tungsten and molybdenum, (iii) metal ions of at least one metal selected from the group consisting of nickel, cobalt, iron and zinc and (iv) 1 to 100 mg/l of chromium ions, at a current density lower than a limiting current density of the plating bath (A), to form on a bonding surface of the copper foil a composite metal layer comprising (I) copper, (II) at least one metal selected from the group consisting of tungsten and molybdenum and (III) at least one metal selected from the group consisting of nickel, cobalt, iron and zinc; and 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 (B) to form a dendritic copper electrodeposition layer and then carrying out subsequent electrolysis at a current density lower than the limiting current density of the plating bath (B) to form nodular copper. In this method, the plating bath (A) contains 5 to 25 g/l of copper ions, 0.006 to 11 g/l of total of tungsten ions and molybdenum ions, 2 to 30 g/l of total of nickel ions, cobalt ions, iron ions and zinc ions and 1 to 100 mg/l of chromium ions and is adjusted to pH 1.5 to 5.0, and the plating bath (B) contains 5 to 76 g/l of copper ions.
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