| 摘要 |
PURPOSE:To improve the reliability upon semiconductor device and the yield thereof while enabling highly selective etching process to be performed by a method wherein a mixed gas of CHF3, CH2F2 and O2 or CHF3, CH3F and O2 is used as an etching gas. CONSTITUTION:A gas easy to produce polymer is used as an etching gas to attain the selection-ratio of silicon and resist, but CHF3 gas only used as etching gas subjected to is a limit to the controllability thereof. Therefore, CH2F2 or CH3F easier to produce polymer is added to CHF3 moreover O2 is added to remove the produced polymer. Through these procedures, a silicon oxide film can be etched with high selectivity for silicon and resist to improve the reliability upon a semiconductor element device and the yield thereof.
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