High-frequency power supply device and reflected wave power control method

A reflected wave power control method for an RF power supply that supplies RF power to a plasma load, said RF power supply comprising:

• an RF generator unit that converts DC of a DC power supply to RF AC through a switching operation and outputs RF power;
• and
• a feedback system that feeds back a detection value of the RF output of said RF generator unit for performing feedback control, wherein
• said feedback system comprises:
• a forward wave power control loop system that feeds back a detection value of forward wave power, which is sent from said RF generator unit to a plasma load, for controlling the forward wave power;
• and
• a plurality of reflected wave power control loop systems each of which feeds back a detection value of reflected wave power, which is sent from said plasma load to said RF generator unit, for controlling the reflected wave power,
• said reflected wave power control loop system comprising:
• a reflected wave power peak value dropping loop system and an arc blocking system that control a peak variation in reflected wave power;
• and a reflected wave power amount dropping loop system that controls a smoothed power amount of reflected wave power, wherein
• said reflected wave power peak value dropping loop system controls a DC voltage of the DC power supply of said RF generator unit based on a peak value of reflected wave power and, through the voltage control of the DC power supply, controls whether to drop the peak value of reflected wave power,
• said arc blocking system controls whether to output from an RF amplifier unit of said RF generator unit, based on the peak value of reflected wave power, to control whether to supply power to the plasma load and thereby controls arc blocking at the plasma load, and
• said reflected wave power amount dropping loop system controls a duty ratio (time ratio) between an ON state and an OFF state of the RF amplifier unit of said RF generator unit, based on a smoothed power amount of reflected wave power, to control a supply amount of power to the plasma load and thereby controls dropping of a power amount of reflected wave power.