Characteristics of Cu-Pd films grown by simultaneous chemical vapor deposition from metalorganic precursors

The strategy of adding alloying elements during the chemical vapor deposition (CVD) of copper to improve the reliability of copper films was investigated. Deposition of Cu-Pd alloy films was demonstrated using low-pressure CVD with (hexafluoroacetylacetonato)copper(I)(vinyltrimethylsilane) [(hfac)Cu(I)vtms] and palladium(II)bis(hexafluoroacetylacetonate) [Pd(hfac)(2)] in the temperature range of 100-200 degrees C in a cold-wall differential reactor. High growth rates of 100-500 nm/min and high-purity films as confirmed by Auger electron spectroscopy (AES) were obtained. As-deposited alloy films showed low resistivities (similar to 2.3 mu Omega cm) at palladium concentrations below 3 wt. %. A high degree of conformality was observed on sub-half-micron trenches with aspect ratios greater than 3.5:1. The co-deposition of copper and palladium resulted in significant inhibition of palladium growth as compared to the independent palladium deposition.