Patent ID: 9558928
Date: 2017-01-31
CPC Classifications: H01J,H01L

Claim:
1. A method of cleaning a substrate having a plurality of high-aspect ratio openings, the method comprising: providing a substrate having a plurality of high-aspect ratio openings into a plasma processing chamber, each of the openings having a height to lateral dimension aspect ratio of greater than about 10:1; flowing a first etchant including a fluorine-based species towards the substrate; applying a first bias power to the plasma processing chamber to generate a plasma of the fluorine-based species to remove silicon oxide in the high-aspect ratio openings; flowing a second etchant including a hydrogen-based species towards the substrate, wherein the second etchant consists only of hydrogen or includes hydrogen and nitrogen trifluoride, a concentration of the hydrogen being greater than a concentration of the nitrogen trifluoride; and applying a source power and a second bias power to the plasma processing chamber to generate a plasma of the hydrogen-based species to remove silicon in the high-aspect ratio openings.