Adjustable dc bias control in a plasma reactor

摘要

A plasma chamber, and a related method for its use, in which the direct current (dc) bias on a wafer-supporting cathode is reduced by including a plasma shield that blocks plasma from reaching a region of the chamber and thereby reduces the effective surface area of a grounded anode electrode. The plasma shield has a number of narrow slits through it, small enough to preclude the passage of plasma through the shield, but large enough to permit pumping of process gases through the shield. The dc bias is further controllable by installing a chamber liner of dielectric or other material to cover a selected portion of the inside walls of the chamber. The liner also facilitates cleaning of the chamber walls to remove deposits resulting from plasma polymerization.