Platinum Metals Rev., 1997, 41, (1), 7
Palladium Aids Insulator Metallisation
Minute copper and nickel patterns can be produced on glass, silica and other insulating materials by using laser-assisted surface activation.
Now investigators at the C.N.R.S., Marseille, France, have reported a simple process in which visible continuous-wave and pulsed lasers can activate spun-on seeding layers of palladium acetylacetonate dissolved in chloroform (G. A. Shafeev, J.-M. Themlin, L. Bellard, W. Marine and A. Cros, J. Vac. Sci. Technol., A, 1996, 14, (2), 319–326). The focused laser beam changes the chemical state of the palladium precursor by pyrolysis. The patterned catalytic film can then promote electroless metal growth.
The quality of the adhesion of the metal deposit to the underlying insulator is very important, and this is determined by the palladium clusters formed when the laser beam activates the catalytic seeding layer. After thermal decomposition the remaining palladium atoms are bonded to one of the two acetylacetonate “wings” of the parent molecule. Removing these ligands by treatment with hot acetic acid allows wear-resistant metal deposits to be formed on insulators.