Directional copper deposition using dc magnetron self-sputtering

A directional copper deposition process has been developed that uses a de magnetron source operating in self-sputtering mode. The process is performed at 10(-5) Torr range pressure where a "long throw" approach can be utilized without discharge enhancement or mechanical collimation due to a very long mean free path of sputtered species. Magnetron sputtering conditions at which the contact hole filling is promoted and substantially enhanced by the self-sputtering process are illustrated and compared to standard sputtering (i.e., short throw, mTorr pressure) in the presence of argon. The experimental parameters of the new process have been explored by depositing Cu on patterned Si wafers with trenches and contact holes of various aspect ratios. (C) 1998 American Vacuum Society.