PLANARIZATION OF ALUMINUM-ALLOY FILM DURING HIGH-RATE SPUTTERING

Planar Al-1%Si and Al-4%Cu films have been deposited over periodic oxide lines 1 mu m thick and valleys of 2 mu m pitch. This was accomplished during high rate magnetron sputtering in a 60-70 s deposition time. The planarizing effect is mostly thermally driven and achieved using a combination of substrate heating (480-510 degree C range) and r. f. bias ( minus 150 to minus 250 v self-bias) during sputtering. It was found that depositing a 0. 1 mu m thick underlayer of TaSi//2//. //4 just prior to the aluminum alloy deposition significantly improves the reliability of the planarization effect.