Symmetrical etching ring with gas control

摘要

In a plasma or RIE etching tool using a uniquely designed annulus around a wafer supporting pedestal, it has been found that the introduction of one or more gases in the region immediately adjacent the annulus controls the amount of etching of features in that region in the surface of the wafer mounted on the pedestal. By so controlling the amount of gas in this region, the slope of the walls of the etched features can be also controlled.