US Patent 7473459 Method of manufacturing a film printed circuit board

A method of manufacturing a film printed circuit board is provided. A film substrate consisting of a polyimide substrate, an alloy layer and a first copper layer is provided. A first lithographic and etching process is performed to pattern the copper layer and the alloy layer and a plurality of conductive line structures is formed on the polyimide substrate. A second copper layer is formed over the polyimide substrate and the conductive line structures. A second lithographic and etching process is performed to pattern the second copper layer.