| 摘要 |
PROBLEM TO BE SOLVED: To suppress or prevent side-etching by specifying the flow rate of inert gas to that of phlorocarbon gas for plasma etching, so that the precision in cross-section shape of the recessed part formed at an insulating film comprising nitrogen is improved. SOLUTION: Insulating films 2b-2d formed between interlayer insulating films 1c-1f comprise, for example, silicon nitride film, and the interlayer insulting film 1d is provided with a channel 3a for forming wiring where the insulating film 2b is exposed above a bottom, with a wiring 4 formed inside it. At the interlayer insulating films 1e and 1f as well as insulating films 2c and 2d, such hole 5 and channel 3b as a partial upper surface of the wiring 4 is exposed from the bottom are formed. Before the hole 5 is entirely formed, the insulating film 2c left at the bottom of the hole 5 is removed by selective etching in CHF3/O2/Ar gas. Here, the flow rate of the Ar gas is 20 times or more of that of CF gas.
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