| 摘要 |
PROBLEM TO BE SOLVED: To provide a dry etching method for tungsten wherein etch-rate is high, side-etch is less, and selectivity against silicon oxide film is excellent. SOLUTION: Firstly, (a) on a semiconductor substrate 101, a silicon oxide film 102 and a tungsten film 103 are formed, and over it, a patterned photo-resist 104 is formed. Then, (b) the semiconductor substrate is set in a dry etching device, and, SF6 , Cl2 and CO are supplied at flow amount ratio of 200:0.5-1.5:20-100, for performing etching. Then, (c) the photo-resist is removed.
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