| abstract |
TITLE SINGLE EXPOSURE PROCESS FOR PREPARING PRINTED CIRCUITS ABSTRACT OF THE DISCLOSURE A process for preparing a two layer printed circuit having conductive interconnections wherein at least one layer of a photoadhesive composition is applied to a substrate bearing an electrically conductive circuit pattern and exposing said photoaadhesive layer or layers through a circuit image of three different optical deensities, i.e., zero, gray and opaque, removing portions of the photosensitive layer by solvent washout applying finely divided metal, alloy or plating catalyst to adherent image areas, optionally curing the printed circuit, e.g., heating or ultraviolet exposure and plating to form an interconnected electrically conductive circuit pattern. Multilayer printed circuits can also be prepared by repeating the steps using additional layers of photoadhesive material. |