| 摘要 |
<p>A method for plasma etching a polysilicon film on a gate oxide film formed on a silicon substrate by introducing processing gas into an airtight processing chamber comprising a main etching step for etching the polysilicon film in the depth direction of an opening made in a mask pattern serving as a mask by applying a high-frequency power to the upper and lower electrodes, and an overetching step for removing the residual part of the polysilicon film following the main etching step, wherein the polysilicon film is etched until a part of the gate oxide film is exposed by lowering the high-frequency power being applied to the upper electrode down to a specified level or below in the middle of the main etching step. Anisotropy in the profile can be improved while enhancing the selection ratio of etching and total etching rate can be prevented from lowering.</p> |
