METHOD FOR MACHINING SILICON BASED MATERIAL LAYER

摘要

PURPOSE:To provide a method for machining a silicon based material layer by which the side wall protective film can be removed sufficiently and efficiently. CONSTITUTION:A polycide 5 deposited on a gate insulating film 2 is subjected to dry etching using an etching gas produced from a chlorine based or a bromine based chemical species and an oxygen based chemical species. A resist mask 7 is then subjected to ashing through plasma processing using an oxygen based gas and carbon components are removed from the interior of a side wall protective film 8 which is subsequently oxidized to have a composition close to that of a stoichiometrically stable SiO2. Thereafter, the modified side wall protective film 8 is removed by processing with diluted hydrofluoric acid solution. Since the side wall protective film can be removed sufficiently, dust can be reduced and the coverage of the film can be improved in the following step. This method enhances the reliability and increases the yield in the production of the semiconductor device.