| abstract |
In an exemplary embodiment, an ALE process for etching oxide is described herein. In one embodiment, the oxide is silicon oxide. The ALE modification step involves the use of a carbon tetrafluoride (CF4 ) based plasma. This modification step preferentially removes oxygen from the surface of the silicon oxide, thereby providing a silicon-rich surface. The ALE removal step involves the use of a hydrogen ( H2 ) based plasma. This removing step removes the silicon-rich monolayer formed in the modifying step. Silicon oxide etch ALE processing utilizing CF4 and H2 steps can be used for a wide range of substrate processing steps. For example, ALE processing can be used for, but not limited to, self-aligned contact etch steps, silicon fin exposure steps, oxide mandrel extraction steps, oxide spacer trim, and oxide liner etch. |