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 assembly is positioned in a reaction chamber to divide the chamber into upper and lower sub-chambers. The plasma grid assembly may include one or more plasma grids having slots of a particular aspect ratio, which allow certain species to pass through from the upper sub-chamber to the lower sub-chamber. Where multiple plasma grids are used, one or more of the grids may be movable, allowing for tenability of the plasma conditions in at least 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.

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; anda grid assembly 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; and
a controller configured to produce the plasma in the chamber under conditions that use the grid assembly to produce an upper zone plasma in the upper sub-chamber and a lower zone plasma in the lower sub-chamber, the lower zone plasma being an ion-ion plasma, wherein the grid assembly comprises at least a first grid and a second grid, each grid comprising a plurality of slots that substantially prevent formation of induced current in the grid when the plasma is produced within the chamber, wherein at least one of the plurality of slots in at least one of the first and second grids in the grid assembly has a height to width aspect ratio between about 0.5-1.