| 摘要 |
PROBLEM TO BE SOLVED: To efficiency form a trench which has high aspect ratio, using a relatively simple means. SOLUTION: An initial trench 4 is formed by etching an Si substrate 1 through reactive ion etching by using an oxide film mask 2 as a mask. Then, after a protective oxide film 11 is formed on the inner wall of the trench 4, the film 11 formed on the bottom of the trench 4 is etched by reactive ion etching together with the substrate 1 which forms the bottom of the trench 4. The steps of forming the protective oxide film 11 and of etching the bottom of the trench 4 are repeated, until the depth of the trench 4 becomes a prescribed value. These steps are performed in the same chamber to perform plasma treatment, by switching the gas species introduced into the chamber.
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