Electroless metal adhesion to organic dielectric material with phase separated morphology

Abstract

Improved adhesion of electroless metal deposited on an organic dielectric layer with phase separated morphology is accomplished by the spontaneous formation of a morphologically and topographically rough surface. In one embodiment a ternary solution of a polar solvent and two polymer precursors of the same polymer which are separable in two phases of different order are cast in film on a substrate and heated to form two phases of different order to spontaneously produce a rough surface. Upon exposure to an alkaline solution, one phase is etched at a faster rate than the other. Seeding and electroless deposition of a metal on the rough surface results in improved adhesion of the metal to the dielectric layer. In a second embodiment a quaternary solution of a polar solvent, a seeding agent, two polymer precursors of the same polymer which are separable in two phases of different order are cast in a thin film on a substrate and heated to form three phases. Upon curing the precursors there is surface roughening as a result of phase separation. Upon exposure to alkaline solution there is etching of one of the polymer phases at a faster rate and simultaneous opening of the seeding colloid. The rough surface is overcoated with a photoresist, exposed and developed. Subsequent electroless metal deposition results in improved metal to dielectric layer adhesion. The method is applicable to selective deposition of electroless copper onto a polyimide layer.

Dependencies are inferred from the claim text.