Metallization of Alumina Ceramics by Electroless-plating

Abstract

To clarify the adhesion mechanism between alumina substrates and electroless-plated films, the adhesion strength was examined using SnCl₂ and PdCl₂, Pd alkali ions, Pd colloid, and Cu colloid for catalytic activation. The result showed that the adhesion strength was little influenced by catalytic activation, and that the adhesion strength of the electroless-plated Cu and the Ni-P film on a substrate with a surface roughness of 0.24μm was 1.5kg mm^-2 and 2.5kg mm^-2, respectively. The adhesion strength of these films was found to be influenced by morphology conditions on the initial deposition of each film. Regardless of the type of catalytic activation, the morphology of the initial deposition of electroless-plated Cu was rough, and granules were deposited on the surface of the alumina substrate, while electroless-plated Ni-P produced a uniform dense film. Therefore, it seemed that the interface region between the substrate and the Cu film is brittler than that between the substrate and the Ni-P film, causing the adhesion strength of the Cu film to always be lower. It was concluded that the initial deposition condition is one of the most important factors in controlling the adhesion strength between the film and the alumina substrate.