Plasma processing apparatus and plasma processing method
View Patent ↗A plasma processing apparatus is offered which has evacuable vacuum vessel, processing chamber disposed inside the vacuum vessel and having inside space in which plasma for processing sample to be processed is generated and in which the sample is placed, unit for supplying gas for plasma generation into processing chamber, vacuum evacuation unit for evacuating inside of processing chamber, helical resonator configured of helical resonance coil disposed outside the vacuum vessel and electrically grounded shield disposed outside the coil, RF power supply of variable frequency for supplying RF electric power in given range to the resonance coil, and frequency matching device capable of adjusting frequency of the RF power supply so as to minimize reflected RF power. The resonance coil has electrical length that is set to integral multiple of one wavelength at given frequency. The helical resonance coil has feeding point connected to ground potential using variable capacitive device.
1. A plasma processing apparatus comprising:
an evacuable vacuum vessel;
a processing chamber disposed inside the vacuum vessel and having an inside space in which a sample to be processed is placed and in which a plasma for processing is generated;
a unit for supplying a gas for plasma generation into the processing chamber;
a vacuum evacuation unit for evacuating the inside of the processing chamber;
a helical resonator configured of a helical resonance coil disposed outside the vacuum vessel and an electrically grounded shield disposed outside the coil;
an RF power supply of a variable frequency for supplying RF electric power in a given range to the resonance coil; and
a frequency matching device capable of adjusting the frequency of the RF power supply so as to minimize reflected RF electric power;
wherein said resonance coil has an electrical length that is set to an integral multiple of one wavelength at said given frequency; and
wherein said helical resonance coil has a feeding point connected to ground potential using a variable capacitive device.
2. The plasma processing apparatus set forth in claim 1 , wherein there is further provided a stationary inductive device connected in parallel with said variable capacitive device.
3. The plasma processing apparatus set forth in claim 1 , wherein the apparatus includes means for making an automatic adjustment of the capacitance of said variable capacitive device such that reflected RF electric power is minimized.