Improved methods and apparatus for ion-assisted etch processing in a plasma processing system are disclosed. In accordance with various aspects of the invention, an elevated edge ring, a grooved edge ring, and a RF coupled edge ring are disclosed. The invention operates to improve etch rate uniformity...http://www.google.es/patents/US6344105?utm_source=gb-gplus-sharePatente US6344105 - Techniques for improving etch rate uniformity
