| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device including a highly selective etching step, which can increase processing accuracy and also can realize highly selective etching of a silicon oxide film to a silicon nitride film, at the time of etching a fine hole having a diameter of 3μm or less. SOLUTION: When a silicon oxide film of a semiconductor device is etched highly selectively to a silicon nitride film, etching is carried out under conditions such that a mixture gas of C4 F8 , CO, O2 and Ar is employed as an etching gas, the C4 F8 gas is supplied at 3-7% of the total gas flow rate, and the Ar gas is supplied at 75-90% of the total gas flow rate. Thereby a high selectivity of the silicon oxide film and silicon nitride film can be realized, and etch stop in a fine contact hole can be suppressed for improving processing accuracy.
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