摘要 |
The temperature of the specimen holder 6 in the vacuum container 1 is lowered with the thermal control unit 11 to adjust the temperature of the specimen 7 composed of a silicon substrate to a low temperature of 0° C. or lower. Then, trenches are formed in the specimen 7 by plasma etching using an etching gas comprising SF6 as the main constituent and optionally O2 as an additive. Thus, the etching rate and the yield can be increased in the trench formation in the silicon semiconductor substrate.
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