Abstract: A process for producing printed circuits including a dry substrate activation process and copper deposition without electroless plating is disclosed. The process requires fewer wet chemical baths, is less environmentally hazardous, and more efficient than conventional processes. Initially, sacrificial copper layers are laminated to the surface of a prepreg substrate and through holes are drilled therein. The sacrificial layer is then removed by etching and copper is sputter deposited upon the substrate surface and the walls of the through holes. Photoresist is then applied, exposed and developed to create the desired pattern of circuit lines. Next, copper is deposited in the photoresist channels and on the through hole walls by electroplating. After the photoresist is stripped, the exposed sputtered copper is removed by differential etching.

Abstract: A method of improving the adherence of conductive metallic lines to a polyimide resin layer by incompletely curing the polyimide resin prior to deposition of the metal layer, and subsequently completely curing the polyimide resin layer after the metal layer is deposited.