Patent ID: 6849154

Claim:
A plasma etching apparatus, comprising: a process chamber in which a target object to be processed is housed; exhaust means for maintaining a desired reduced pressure state within the process chamber; gas introducing means for introducing an etching gas into the process chamber; first and second electrodes arranged a predetermined distance apart from each other and to face each other within the process chamber, said target object being supported on said second electrode to face said first electrode; first high frequency apply means for applying a first high frequency power to the first electrode so as to cause said etching gas to form a plasma between the first electrode and the second electrode; second high frequency apply means for applying a second high frequency power having a frequency lower than that of the first high frequency power to the second electrode; third high frequency apply means for superposing a third high frequency power having a frequency lower than that of the first high frequency power and higher than that of the second high frequency power on the first high frequency power; and phase control means for adjusting the phase difference between the second high frequency power and the third high frequency power.