INTERNAL PLASMA GRID FOR SEMICONDUCTOR FABRICATION

摘要

The embodiments disclosed herein pertain to improved methods and apparatus for etching a semiconductor substrate. A plasma grid is positioned in a reaction chamber to divide the chamber into upper and lower sub-chambers. The plasma grid may have slots of a particular aspect ratio which allow certain species to pass through from the upper sub-chamber to the lower sub-chamber. In some cases, an electron-ion plasma is generated in the upper sub-chamber. Electrons that make it through the grid to the lower sub-chamber are cooled as they pass through. In some cases, this results in an ion-ion plasma in the lower sub-chamber. The lower sub-chamber plasma has a lower electron density, lower effective electron temperature, and higher negative ion:positive ion ratio as compared to the upper sub-chamber plasma. The disclosed embodiments may result in an etching process having good center to edge uniformity, selectivity, profile angle, and Iso/Dense loading.

主权项

1. An apparatus for etching a feature on a substrate, the apparatus comprising:
a chamber defining an interior where a plasma can be provided; a substrate holder for holding a substrate in the chamber during etching; a plasma generator for producing a plasma within the chamber; and a grid dividing the interior of the plasma chamber into an upper sub-chamber proximate the plasma generator and a lower sub-chamber proximate the substrate holder, wherein the upper sub-chamber has a height that is at least about ⅙ that of the lower sub-chamber, wherein the grid comprises a plurality of slots that extend substantially radially outwards that substantially prevent formation of induced current in the grid when the plasma is produced within the chamber.