| 摘要 |
PURPOSE:To enable SiO2 to be etched uniformly under a high selectivity, by utilizing a mixture of CCl4 and He as a processing gas and supplying CCl4 and He at a specific flow ratio for causing plasma discharge under a specific relation between a partial pressure of CCl4 and a power density of high-frequency power. CONSTITUTION:A vacuum chamber 1 is evacuated through a vacuum exhaust tube 17 and a mixture of CCl4 and He gases is introduced thereinto through a gas inlet tube 5 to a predetermined pressure. Simultaneously, high-frequency power is applied by a high-frequency power supply 8 so that plasma discharge is caused to etch an object to be treated. The rate of flows of CCl4 and He should be 0.1<=CCl4/He<=0.3. Further, plasma discharge should be caused under conditions satisfying PCCl4 omega(W/cm<2>) when PCCl4(Pa) is a partial pressure of CCl4 and omega is a power density. If PCCl4=10omega, uniformity of etching is deteriorated. In order to create CCl4 plasma stably and uniformly, it is required to satisfy the conditions as above mentioned. Maximum speed ratio can be obtained in a rage of 0.1<=CCl4/He<=0.3.
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