ETCHING GAS COMPOSITION FOR POLYCRYSTAL SILICON FILM AND TUNGSTEN SILICIDE FILM FOR MANUFACTURE OF SEMICONDUCTOR DEVICE AND PLASMA ETCHING METHOD USING IT

摘要

PROBLEM TO BE SOLVED: To obtain a plasma etching method in which an isotropic etching characteristic and a selective ratio with reference to an oxide film are enhanced, by a method wherein an etching gas composition for a polycrystal silicon film and a tungsten silicide film for the manufacture of a semiconductor device is composed of chlorine gas and of oxygen gas. SOLUTION: An etching gas composition which is composed of 77 to 98 wt.% of chlorine gas acting as a main etching gas and of 2 to 23 wt.% of oxygen gas acting as an auxiliary etching gas is used, and a polycrystal silicon film and a tungsten silicide film which are deposited on a semiconductor substrate are etched. Then, the oxygen gas removes the pattern profile of the polycrystal silicon film and the tungsten silicide film which are formed on the semiconductor substrate which is etched by the chlorine gas in a radical or ion state. As a result, a plasma etching method is excellent in an isotropic etching characteristic and in a selective ratio with reference to an oxide film.