COMPARISON OF PROCESSES FOR SELECTIVE ELECTROLESS COPPER PLATING ON 96-PERCENT ALUMINA PHOTO-SELECTIVELY ACTIVATED USING CHLORINATED AND NONCHLORINATED PHOTOCHEMICAL COATINGS - PHOTOACTIVITY AND RELIABILITY STUDIES

Photo-activation processes using a wide variety of photochemical coati ngs as activation precursors have been reported in recent years. This work presents a comparison of a series of chlorinated and non-chlorina ted photochemicals in a photo-activation process for electroless coppe r metallization on alumina ceramic substrates. A purpose-built KrCl e xcimer lamp contact mask aligner was used for the photo-selective acti vation step. UV spectral studies show that two chlorinated photochemic als are less susceptible to photolysis in a 222 nm excimer lamp contac t mask aligner than the non-chlorinated photochemical. Evidence has be en found that the photolysis process is temperature assisted and requi res elevation of the substrate to temperatures in the range 60-80 degr ees C for decomposition to take place on a time scale of the order of tens of minutes. Adhesion. resistivity and sawability test results for the electroless copper metallizations on 96% alumina activated are pr esented. (C) 1998 Published by Elsevier Science S.A.