Plasma processing apparatus and waveform correction method

1. A plasma processing apparatus including an electrode to which a high frequency for plasma generation is applied and which serves as a mounting table for a target object, the apparatus comprising:

a high frequency generation unit configured to generate the high frequency by using waveform data including a set frequency component having a predetermined frequency;

a distortion component extraction unit configured to extract a distortion component given to the high frequency in a path for transmitting the high frequency generated by the high frequency generation unit to the electrode; and

a waveform correction unit configured to correct the waveform data by combining an antiphase component obtained by inverting a phase of the distortion component and the set frequency component of the waveform data used for generation of the high frequency.

2. The plasma processing apparatus of claim 1 , wherein the distortion component extraction unit includes:

a waveform acquisition unit configured to acquire a waveform of a power of the high frequency applied to the electrode, a difference between the power of the high frequency and power of a reflection wave obtained by the high frequency being reflected by a plasma, or a voltage value of the electrode;

a Fourier transformation unit configured to extract a plurality of frequency components included in the waveform by performing Fourier transformation on the waveform; and

a comparison unit configured to extract, as the distortion component, a frequency component other than the set frequency component by comparing the respective frequency components and the set frequency component.

3. The plasma processing apparatus of claim 2 , wherein the distortion component extraction unit further includes a voltage measuring unit configured to measure, as the voltage value of the electrode, a voltage of a path for transmitting the high frequency generated by the high frequency generation unit to the electrode, and

the waveform acquisition unit acquires a waveform of the voltage of the path which is measured by the voltage measuring unit.

4. The plasma processing apparatus of claim 2 , wherein an electrostatic chuck configured to attract and hold the target object by an electrostatic force is provided on the electrode,

the distortion component extraction unit further includes a voltage measuring unit configured to measure a voltage of the electrostatic chuck as the voltage value of the electrode, and

the waveform acquisition unit acquires a waveform of the voltage of the electrostatic chuck which is measured by the voltage measuring unit.

5. The plasma processing apparatus of claim 2 , wherein a focus ring is provided on the electrode to surround a region on which the target object is mounted,

the distortion component extraction unit further includes a voltage measuring unit configured to measure a voltage of the focus ring as the voltage value of the electrode, and

the waveform acquisition unit acquires a waveform of the voltage of the focus ring which is measured by the voltage measuring unit.

6. A waveform correction method in a plasma processing apparatus including an electrode which serves as a mounting table for a target object and to which a high frequency for plasma generation is applied, the method comprising:

generating the high frequency by using waveform data including a set frequency component having a predetermined frequency;

extracting a distortion component given to the high frequency in a path for transmitting the generated high frequency to the electrode; and,

correcting the waveform data by combining an antiphase component obtained by inverting a phase of the distortion component and the set frequency component of the waveform data used for high frequency generation.