| 摘要 |
An etching method capable of controlling the film thickness of a hard mask layer uniformly is provided. A plasma etching is performed on a native oxide film by using an etching gas containing, for example, CF4 and Ar while a thickness of a silicon nitride film is being monitored and the etching is finished when the thickness of the silicon nitride film reaches a predetermined value. Then, a plasma etching is performed on a silicon substrate by employing an etching gas containing, for example, Cl2, HBr and Ar and using the silicon nitride film as a mask while a depth of a trench is being monitored and the etching is finished when the depth of the trench reaches a specified value.
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