Laser interconnect process

Claim 1

A process for forming a desired conductor pattern on a patterned surface of a substrate comprising: providing said patterned substrate, said substrate including a surface pattern of areas having differing characteristics selected from the group consisting of composition, optical reflectivity, optical absorptivity and thermal conductivity; providing a buffer layer on said substrate patterned surface, said buffer layer extending across at least two areas of said surface pattern having differing characteristics; laser illuminating said buffer layer in said desired conductor pattern in the presence of a catalyst source compound to form a layer of an electroless plating catalyst on said buffer layer in said desired conductor pattern; said formation of said catalyst pattern being by decomposition of said catalyst source compound to provide said catalyst on said buffer layer and where said differing characteristics would affect said decomposition in the absence of said buffer layer; and exposing said catalyst patterned buffer layer to an electroless plating environment to deposit electroless metal on said buffer layer in a pattern determined by the pattern of said catalyst.