Wiring level production on a support, especially for multilayer circuit board production, involves leaving an exposed and developed photosensitive resin layer as insulation between conductive regions

摘要

Circuit board wiring level production on a support involves leaving an exposed and developed photosensitive resin layer as insulation between conductive regions. Production of one or more overlying circuit board wiring levels on a support comprises: (a) applying a metallization nucleating layer over the entire support surface; (b) applying a photosensitive resin layer on the nucleating layer; (c) lithographically structuring the resin layer by exposure with a circuit pattern and developing for resin removal from the circuit regions to be metallized; and (d) selectively growing metal in the circuit regions by electroless plating to form a corresponding wiring level metal layer. An Independent claim is also included for production of one or more overlying circuit board wiring levels on a support by: (a') preparing the support and a metal foil carrier; (b') applying a photosensitive resin layer (2) on one or both sides of the foil carrier; (c') lithographically structuring the resin layer by exposure with a circuit pattern and developing for resin removal from the circuit regions to be metallized; (d') selectively forming a wiring level metal layer (5) in the circuit regions; (e') joining the support to the wiring level side of the structure; and (f) removing the foil carrier. Preferred Features: The metal foil carrier consists of several overlying separable foil layers and the foil carrier removal step (f) involves stripping a foil layer from an adjacent foil layer. When the resin layer (2) is applied to both sides of the foil carrier, the foil carrier removal step (f) involves stripping two foil layers from adjacent foil layers. The foil carrier comprises a strippable thick metal foil layer (1a) having a thin metal foil layer (1b) on one or both sides. One or more further overlying wiring levels may be formed after metal layer formation and before application of the support. Joining of the support and the structure is carried out using an interposed prepreg or adhesive foil layer. In the second process, the metal layer may be formed by electroplating or electroless plating.