SELECTIVE CHEMICAL-VAPOR-DEPOSITION OF PLATINUM AND PALLADIUM DIRECTED BY MONOLAYERS PATTERNED USING MICROCONTACT PRINTING

High-purity platinum and palladium thin films can be deposited selecti vely by combining microcontact printing (mu CP) and metal-organic chem ical vapor deposition (MOCVD). Printed patterns of octadecyltrichloros ilane thin films are used to direct the selective deposition of the me tallic thin films from bis(hexafluoroacetylacetonato)platinum(II), Pt( hfac)(2), and bis(hexafluoroacetylacetonato)palladium(II), Pd(hfac)(2) , in the presence of hydrogen. This process has been used successfully to fabricate Pt and Pd patterns on substrates such as titanium nitrid e, indium tin oxide, silicon dioxide, and sapphire. Features with size s as small as 1.5 mu m have been deposited by this combined mu CP-MOCV D method. The Pt and Pd films were found to be free of detectable impu rities, as measured by X-ray photoelectron and Auger electron spectros copies. Grain sizes in the deposits can also be varied. We found, for example, that the Pt film growth process yields heavily faceted deposi ts whose habits depend strongly on the temperature of the substrate du ring processing. Addition of water vapor to the reactor feed during pl atinum chemical vapor deposition increased the number of nucleation si tes, thus reducing the grain size, but did not otherwise affect the de position rate to a significant degree. We describe in this report how this photolithography-free process might simplify the patterning of me tal and other thin films of interest in integrated circuit fabrication .