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) typ ically contain high percentages of carbon and exhibit poor electrical conductivities. The role of atomic H in the removal of carbonaceous im purities was investigated using quartz crystal microbalance mass depos ition rate measurements, x-ray photoelectron spectroscopy compositiona l 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. Simu ltaneous 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 sput tering with ions alone. The primary products detected with the additio n of H were CH4 and CH3. High purity (similar to 99 at.%) Cu films wit h resistivities of similar to 5 mu Omega cm were achieved at room temp erature with use Of the H atom beam. The Cu content represents the hig hest purity ever reported using II-CVD at room temperature. (C) 1997 A merican Vacuum Society.