Selective metallization process

A selective metallization process comprising the steps of providing a patterned mask on a substrate, treating the patterned substrate so as to provide a catalytic layer thereon and electrolessly plating the catalyzed substrate with the patterned mask thereon, including the step of treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without substantial attack or modification of the exposed substrate before and/or after catalyzation and prior to electroless plating so as to prevent electroless plating on the mask, said weak acid comprising an aqueous solution of a member of the group consisting of acetic acid, formic acid and propionic acid.

A selective metallization process comprising providing a patterned negative mask on at least one surface of a substrate, said surface comprising an epoxy resin, treating the patterned substrate so as to create micropores on the exposed substrate, treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without attacking the substrate surface, so as to prevent electroless plating on the mask then catalyzing the patterned substrate and electrolessly plating the catalyzed substrate with the mask still intact thereon such that said plating occurs on the exposed substrate but not on the mask.