METHOD FOR VOID-FREE COBALT GAP FILL

摘要

The present invention provides methods of depositing void-free cobalt into features with high aspect ratios. Methods involve the following steps: (a) partially filling a feature with cobalt; (b) exposing the feature to plasma generated from nitrogen-containing gas to selectively inhibit cobalt nucleation on surfaces near or at the top of the feature; optionally repeating the steps (a) and (b), and depositing bulk cobalt into the feature by chemical vapor deposition. The methods may also involve exposing a feature including a barrier layer to the plasma generated from the nitrogen-containing gas to selectively inhibit cobalt nucleation. The methods may be performed at low temperatures less than about 400°C by using cobalt-containing precursors.