Plasma processing apparatus
AssigneesTokyo Electron Limited, DAIHEN Corporation
InventorsHiroo Konno, Shunsuke Kadooka
Life of this patent
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Abstract
In a plasma processing apparatus, target values for feedback control to be applied to a progressive wave power PF as control parameters, i.e., control instruction values Con and Coff are switched during a pulse-on period Ton and a pulse-off period Toff in each cycle of a modulation pulse, respectively. That is, a first feedback control for making the progressive wave power PF approximate to a first control instruction value Con is performed during the pulse-on period Ton, whereas a second feedback control for making the progressive wave power PF approximate to a second control instruction value Coff is performed during the pulse-off period Toff.
Claims8
A plasma processing apparatus of generating plasma by high frequency discharge of a processing gas within a decompression processing vessel that accommodates therein a processing target object, which is loaded into and unloaded from the processing vessel, and performing a process on the processing target object within the processing vessel under the plasma, the plasma processing apparatus comprising:
- a first high frequency power supply configured to output a first high frequency power;
- a first high frequency transmission line configured to transmit the first high frequency power outputted from the first high frequency power supply to a first electrode provided within or in the vicinity of the processing vessel;
- a second high frequency power supply configured to output a second high frequency power;
- a second high frequency transmission line configured to transmit the second high frequency power outputted from the second high frequency power supply to the first electrode or a second electrode provided within or in the vicinity of the processing vessel;
- and
- a power modulation unit configured to pulse-modulate an output of the second high frequency power supply with a pulse such that a first period during which the second high frequency power is turned on or has a first level and a second period during which the second high frequency power is turned off or has a second level lower than the first level are repeated alternately at a regular frequency,
- wherein the first high frequency power supply comprises:
- a RF power monitor configured to detect a progressive wave power propagating on the first high frequency transmission line from the first high frequency power supply toward the first electrode in a forward direction and a reflection wave power propagating on the first high frequency transmission line from the first electrode toward the first high frequency power supply in a backward direction, and configured to generate a progressive wave power detection signal indicating the progressive wave power and a reflection wave power detection signal indicating the reflection wave power;
- a load power measurement unit configured to calculate a measurement value of a load power applied to a load including the plasma from the progressive wave power detection signal and the reflection wave power detection signal obtained from the RF monitor;
- and
- a high frequency power output control unit configured to perform feedback controls on the progressive wave power during the first period and the second period, independently and respectively, in each cycle of the pulse such that the measurement value of the load power obtained from the load power measurement unit is equal to or approximate to a preset load power set value.
Dependencies are inferred from the claim text.