A dry etching method of a polyzids without the use of cfcs - gases

摘要

PURPOSE: To enable one-stage anisotropic etching of a W-polycide film without using CFC(chlorofluorocarbon) gas. ;CONSTITUTION: A W-polycide film 5 is etched by using sulfur halogenide like S₂Al₂ and S₂Br₂ as etching gas. S and Cl*, Br* generated from the sulfur halogenide contribute to the formation of a side wall protecting film and etching seeds, respectively. The boiling points of WCl_x and WBr_x which are formed at the time of etching a WSi_x layer 4 on the upper layer side are high at a normal temperature and a normal pressure, but the vapor pressure necessary for elimination is obtained under low pressure heating. When a wafer is heated at a level that S does not sublime, ething progresses sufficiently. Since F* is not formed in plasma, undercut is not generated in a polycrystalline silicon layer 3, and C also does not exist, so that particle contamination and selectivity deterioration to a gate oxide film 2 can be prevented.;COPYRIGHT: (C)1993,JPO&Japio