Comparison of processes for selective electroless copper plating on 96% alumina photo-selectively activated using chlorinated and non-chlorinated photochemical coatings: photoactivity and reliability studies

• Published in: Surface & coatings technology 1997-06, Vol.100-101 (1-3), p.238-242
• Main Authors: Kelly, P V, Macauley, D J, Mongey, K F, Crean, G M
• Format: Article
• Language: English
• ISSN: 0257-8972

Photo-activation processes using a wide variety of photochemical coatings as activation precursors have been reported in recent years. This work presents a comparison of a series of chlorinated and non-chlorinated photochemicals in a photo-activation process for electroless copper metallization on alumina ceramic substrates. A purpose-built KrCl exp * excimer lamp contact mask aligner was used for the photo-selective activation step. UV spectral studies show that two chlorinated photochemicals are less susceptible to photolysis in a 222 nm excimer lamp contact mask aligner than the non-chlorinated photochemical. Evidence has been found that the photolysis process is temperature assisted and requires elevation of the substrate to temperatures in the range 60-80 deg 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 presented.