| CPC H05K 3/027 (2013.01) [C25D 5/48 (2013.01); H05K 3/04 (2013.01); H05K 3/423 (2013.01); H05K 2203/107 (2013.01)] | 7 Claims |
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1. A subtractive method for manufacturing a circuit board with fine interconnect, comprising:
preparing a wiring substrate, including disposing a metal foil layer on a first surface of the wiring substrate;
performing a drilling process to form at least one through hole penetrating through the wiring substrate and the metal foil layer on the first surface;
performing a metal plating process to form an electroplating layer on the metal foil layer of the first surface of the wiring substrate and on an inner wall of the at least one through hole, wherein both the metal foil layer and the electroplating layer on the first surface are combined as a first metal layer;
disposing a resist film on the first metal layer and on the inner wall of the at least one through hole, the resist film being made of a metal material different from metal materials of which the metal foil layer and the electroplating layer are made;
performing a laser dry etching process to etch from a surface of the resist film towards the first surface to form an opening corresponding to a first wiring pattern, the opening penetrating the resist film and forming a first wiring pattern groove in the first metal layer, wherein a depth of the first wiring pattern groove is less than a thickness of the first metal layer;
performing a wet etching process to etch and penetrate the first metal layer from the first wiring pattern groove of the first metal layer to form wirings in the first metal layer; and
removing the resist film.
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