Method for forming wiring on insulating resin layer

摘要

The method for forming wiring includes: laminating a thermosetting resin film in a semi-cured state and a metallic foil in this order on an insulating substrate where base-layer wiring is formed, a mat surface of the metallic foil facing the resin film, pressing the film and the foil with application of heat; forming an opening in the metallic foil so as to expose a part of the insulating resin layer in which a via hole is to be formed; forming the via hole in the insulating resin layer by irradiating high-energy beams on to insulating resin layer by using as a mask the metallic foil in which the opening is formed; performing a desmear process of the via hole via the opening of the metallic foil; removing the metallic foil by etching; forming an electroless-plated layer that continuously covers the top surface of the insulating resin layer, a side surface of the via hole and a top surface of the base-layer wiring corresponding to the bottom of the via hole; and forming wiring including an electroplated layer on the electroless-plated layer by a semi-additive process.