Ion-induced chemical vapor deposition of high purity Cu films at room temperature using a microwave discharge H atom beam source

Films deposited via ion-induced chemical vapor deposition (IZ-CVD) typically contain high percentages of carbon and exhibit poor electrical conductivities. The role of atomic H in the removal of carbonaceous impurities was investigated using quartz crystal microbalance mass deposition rate measurements, x-ray photoelectron spectroscopy compositional analysis, and laser-induced thermal desorption coverage measurements. A surface kinetic model for the ion-enhanced etching of C with H is formulated based upon experiments conducted on carbon substrates. Simultaneous Ar ion and H atom bombardment lead to high etching yields of similar to 15 C/Ar+ at H atom to Ar ion flux ratios of similar to 3000:1. During H-assisted II-CVD, the H serves to enhance the removal of C through ion-enhanced chemical sputtering in addition to physical sputtering with ions alone. The primary products detected with the addition of H were CH4 and CH3. High purity (similar to 99 at.%) Cu films with resistivities of similar to 5 mu Omega cm were achieved at room temperature with use Of the H atom beam. The Cu content represents the highest purity ever reported using II-CVD at room temperature. (C) 1997 American Vacuum Society.