| 摘要 |
PURPOSE:To obtain anisotropic shape without using a complex device while simplifying a reaction system as much as possible, by properly regulating etching by light irradiation and timing of discharge. CONSTITUTION:A pile film of a reaction product in progress of etching is thin in its central part while being thick toward a side wall 8, and light irradiation is interrupted to perform discharge for some what removing the pile film 6. When later the etching through light irradiation is again performed, a quantity of arriving active species is reduced owing to the large thickness of the pile film 6 in the part near the sidewall 8 so as to make etching progress slow, while the etching makes progress relatively fast in the central part 8 due to the thinnese of the film. Accordingly, when a cycle of etching and discharge is repeated while sufficiently reducing etching time so as not to cause a large undercut at one time, shape abnormality such as an undercut can be efficiently prevented. Thereby, anisotropic etching can be easily achieved without making a device complex and causing no damage to the material to be etched.
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