Patent ID: 7476624

Claim:
A dry etching method for etching a polysilicon layer formed on a silicon oxide film layer through a mask layer having a predetermined pattern shape formed on the polysilicon layer, the method comprising: a main etching process for performing a plasma etching under a first pressure lower than 13 Pa by using a main etching gas containing at least an HBr gas; and an overetching process for performing, after the main etching process, a plasma etching under a second pressure ranging from 13 Pa to 27 Pa, which is higher than that of the main etching process, wherein the overetching process includes a first overetching process employing a first overetching gas and a second overetching process employing a second overetching gas following the first overetching process, wherein each of the overetching gases is a mixture gas of HBr and O 2 or the HBr gas, and wherein a pressure in the second overetching process is set to be higher than that in the first overetching process.