Patent ID: 7279429

Claim:
A method for etching at least a portion of at least one layer of a semiconductor wafer to expose one or more underlying layers, the method comprising: placing a semiconductor wafer in a plasma reactor; supplying an etchant source gas to the plasma reactor, the etchant source gas comprising: (a) at least one reactive compound; and (b) at least one ignition gas, wherein the at least one ignition gas increases the ignitability of the etchant source gas as compared to the ignitability of the etchant source gas lacking the at least one ignition gas; igniting the etchant source gas via the application of a RF energy source; and etching at least a portion of the at least one layer in the semiconductor wafer, wherein flow of the at least one ignition gas is stopped to ensure that the at least one ignition gas does not react in the etching, and wherein the at least one ignition gas is selected from chlorine, chlorine-containing gases, bromine, bromine-containing gases, or mixtures of two or more thereof.