Patent attributes
The disclosed embodiments relate to methods and apparatus for removing material from a substrate. In various implementations, conductive material is removed from a sidewall of a previously etched feature such as a trench, hole or pillar on a semiconductor substrate. In practicing the techniques herein, a substrate is provided in a reaction chamber that is divided into an upper plasma generation chamber and a lower processing chamber by a corrugated ion extractor plate with apertures therethrough. The extractor plate is corrugated such that the plasma sheath follows the shape of the extractor plate, such that ions enter the lower processing chamber at an angle relative to the substrate. As such, during processing, ions are able to penetrate into previously etched features and strike the substrate on the sidewalls of such features. Through this mechanism, the material on the sidewalls of the features may be removed.
