| 摘要 |
To determine an optimum addition ratio of ethyl alcohol in the etching gas in a plasma etching unit, an ethyl alcohol addition ratio at which the isotropic etching rate of the etching mask is obtained, and on the basis of the obtained ethyl alcohol addition ratio, the optimum addition ratio is determined, by performing an etching process using an etching gas containing ethyl alcohol in the optimum addition ratio, the portions of the bottom antireflective coating which are not covered with the etching mask are removed. Thus, it is possible to provide a novel etching method capable of appropriately removing unnecessary portions of the bottom antireflective coating which are not covered by photoresist without causing much damage to the photoresist used as the etching mask.
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