Etching method and apparatus
AssigneeTokyo Electron Limited
InventorsSusumu Saito, Akitaka Shimizu
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Abstract
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.
Claims5
An etching method of a substrate to be processed including a mask layer having a pattern;
- a native oxide film to be etched, formed in a groove portion of the pattern;
- and a silicon layer formed beneath the mask layer and the native oxide film to be etched, wherein the native oxide film is formed on a surface of the silicon layer in the groove portion, the etching method comprising:
- performing a first etching on the mask layer and the native oxide film by using a first plasma and monitoring a thickness of the mask layer during the first etching, wherein the first etching is finished when the thickness of the mask layer is reduced to a threshold value;
- performing a second etching on the silicon layer by using a second plasma, wherein the etched mask layer is used as a mask.
Dependencies are inferred from the claim text.