Plasma-etching process for molybdenum silicon nitride layers on half-tone phase masks based on gas mixtures containing monofluoromethane and oxygen

摘要

A method for etching phase shift layers of half-tone phase masks includes etching a phase shift layer by using a plasma which is obtained from CH3F and O2. A high cathode power is used for the etching. The method has a very high selectivity between the substrate and the phase shift layer, so that half-tone phase masks with a high imaging quality can be produced.