Method of treating surface of sample

Abstract

In order to provide a method of treating a multilayer including metal and polysilicon for use in a conductor or a gate electrode of a semiconductor device with high accuracy at a high selectivity, the temperature of a sample is maintained at 100° C. or higher at the time of etching a metal film to increase the etch rate of the metal film. In order to suppress the etch rate of a polysilicon film and prevent side etching, an oxygen gas is added to a gas containing a halogen element. In order to suppress the etch rate of a silicon oxide film at the time of etching the polysilicon film, the etching is performed with etch parameters which are divided into those for the metal film and those for the polysilicon film. In the etching performed to the multilayer containing metal and polysilicon, by etching the metal film at a high temperature of 100° C. or higher, the etch rate of the metal film becomes high. Consequently, there is no partial etch residue of the metal film and a barrier film. By switching the parameters to those with which the polysilicon film can be etched at a high selectivity with respect to an oxide film at the time point of completion of etching to the barrier film, very accurate treatment can be realized.