Patent ID: 7712212

Claim:
A method of producing a multilayer printed circuit board comprising: providing a structure having a substrate, at least one lower conductor circuit and an insulating layer, the at least one lower conductor circuit being formed on the substrate and having a surface at least partially roughened, the insulating layer being formed on the substrate and at least one lower conductor circuit; forming at least one opening for a viahole structure extending from the insulating layer to the at least one lower conductor circuit by applying a laser beam so that a portion of an upper surface of the at least one lower conductive circuit is exposed by the at least one opening; subjecting the insulating layer, the side wall of the at least opening and the exposed portion of the upper surface of the at least one lower conductive circuit to an electroless plating so as to form an electroless plated film; forming a plating resist on the electroless plated film; subjecting the electroless plating layer and the plating resist over the insulating layer to an electrolytic plating so as to form an electrolytic plated film; removing the plating resist; etching and removing the electroless plated film exposed by a pattern of the plating resist to form at least one upper conductor circuit comprising the electroless plated film and the electrolytic plated film, and the viahole structure electrically connected between the lower conductor circuit and the upper conductor circuit; and roughening a surface including a side surface of the upper conductor circuit.