Apparatus for plasma processing

An apparatus for processing a substrate with plasma, comprising:

• a chamber provided with an antenna and configured to accommodate the substrate;
• a microwave generator configured to generate a microwave having a center frequency, power, and a bandwidth respectively corresponding to a setting frequency, setting power, and a setting bandwidth;
• a waveguide configured to guide the microwave output by the microwave generator to the antenna;
• a demodulator provided in the waveguide and configured to measure travelling wave power and reflected wave power of the microwave for each frequency;
• and
• a controller connected to the microwave generator and the demodulator and has a storage unit, wherein
• the controller is configured to
• control the microwave generator to generate the microwave in correspondence to the setting frequency, the setting power, and the setting bandwidth at a first timing,
• control the demodulator to measure the travelling wave power and the reflected wave power of the microwave for each frequency, and calculates a frequency spectrum that is a ratio between the travelling wave power and the reflected wave power for each frequency on the basis of a measurement result from the demodulator,
• store the frequency spectrum related to the first timing into the storage unit,
• control the microwave generator to generate the microwave in correspondence to the setting frequency, the setting power, and the setting bandwidth at a second timing at which time has elapsed from the first timing,
• control the demodulator to measure the travelling wave power and the reflected wave power of the microwave for each frequency, and calculates the frequency spectrum related to the second timing on the basis of a measurement result from the demodulator,
• calculate a correction value for correcting a waveform of the travelling wave power for each frequency such that a difference for each frequency between the frequency spectrum related to the second timing and the frequency spectrum related to the first timing, stored in the storage unit, is small, and
• control the microwave generator to correct the waveform of the travelling wave power on the basis of the calculated correction value for each frequency.