| abstract |
The disclosed embodiments are related to methods and apparatus for removing material from a substrate. In various implementations, the conductive material is removed from sidewalls of features on the semiconductor substrate that have been previously etched (eg, trenches, holes, or pillars). In practicing the techniques herein, a substrate is disposed in a reaction chamber that is separated into an upper plasma generating chamber and a lower processing chamber by a corrugated ion extraction plate having pores therethrough. The extraction plate is corrugated such that the plasma sheath can follow the shape of the extraction plate, thereby allowing ions to enter the lower processing chamber at an angle relative to the substrate. Thus, during processing, ions can penetrate into previously etched features while striking the substrate to the sidewalls of such features. Through this mechanism, the material on the sidewalls of the features can be removed. |