| 摘要 |
PURPOSE: A plasma etching apparatus is provided to improve an oxide-to-PR selection ratio by applying a lower frequency power than that of the bottom electrode to the top electrode. CONSTITUTION: A wafer is etched in a chamber(10). A gas injector injects the gas to the inside of chamber. A high frequency power is applied to the top electrode(13). The high frequency power makes the gas plasma. A first low frequency power is applied to the bottom electrode(14). The first low frequency power induces the plasma to the wafer. The second low frequency power is applied to the top electrode. The second low frequency power has the frequency lower than the first low frequency power.
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