Voltage waveform controlling method, substrate processing method, and substrate processing apparatus

Abstract

Provided is a voltage waveform control method comprising generating a voltage waveform of a non-sinusoidal wave comprising a pulse period having a positive bias voltage, a ramp period having a negative bias voltage, a first transition period changing from the pulse period to the ramp period, and a second transition period changing from the ramp period to the pulse period, adjusting a length of a negative voltage period having the negative bias voltage during a period of the voltage waveform to be at most 20% of a total length of the period, adjusting a slope of the ramp period, and outputting an adjusted voltage waveform based on the adjusted length of the negative voltage period and the adjusted slope of the ramp period, where the adjusting the length of the negative voltage period comprises adjusting a length of the first transition period and a length of the second transition period.