Reactive deposition of conformal palladium films from supercritical carbondioxide solution

High-purity palladium films were deposited onto Si wafers and polyimide by the reduction of organopalladium compounds in supercritical CO2 solution us ing a batch process at temperatures between 40 and 80 degrees C and pressur es between 100 and 140 bar. Hydrogenolysis of pi-2-methylallyl(cyclopentadi enyl)palladium(II) in CO2 at 60 degrees C is complete in less than 2 min, y ielding continuous, 100-200 nm thick, reflective films and the benign, full y hydrogenated ligand decomposition products, cyclopentane and isobutane. A nalysis of the deposited films by X-ray photoelectron spectroscopy indicate s that they are free of ligand-derived contamination. Deposition of thin fi lms on patterned silicon wafers having feature sizes as small as 0.1 mu m w ide by 1.0 mu m deep is strictly conformal, including uniform coverage of t he lower corners and bottoms of the trenches. Deposition by hydrogenolysis of palladium(II) hexafluoroacetylacetonate also yields high-quality films w hile deposition using pi-allyl-(2,4-pentanedionato)palladium(II) is sensiti ve to fluid-phase decomposition of the precursor and yields nonuniform depo sits.