Automatic impedance tuning with RF dual level pulsing

摘要

Methods and systems for RF pulse reflection reduction are provided herein. In some embodiments, a method includes (a) providing a plurality of pulsed RF power waveforms from a plurality of RF generators to a process chamber during a first duty cycle, (b) measuring a first power level impedance Z1 and a different second power level impedance Z2 at different time periods during the first duty cycle, (c) adjusting the second power level impedance Z2 towards 50 ohm such that a standing wave ratio (SWR) of the second power level impedance Z2 decreases towards 50 ohm and a SWR of the first power level impedance Z1 increases from 50 ohm, and (e) repeating (d) until the SWR of the first power level impedance Z1 is substantially equal to the SWR of the second power level impedance Z2.

主权项

1. A method comprising:
(a) providing a plurality of pulsed RF power waveforms from a plurality of RF generators to a process chamber during a first duty cycle, and providing a pulse switch timing signal from one of the plurality of RF generators to synchronize the plurality of pulsed RF power waveforms from the plurality of RF generators; (b) measuring a first power level impedance Z1 and a different second power level impedance Z2 at different time periods during the first duty cycle; (c) adjusting the first power level impedance Z1 to 50 ohm; (d) further adjusting the first power level impedance Z1 such that a standing wave ratio (SWR) of the first power level impedance Z1 increases from 50 ohm, and adjusting the second power level impedance Z2 such that a SWR of the second power level impedance Z2 decreases; and (e) repeating (d) until the SWR of the first power level impedance Z1 is substantially equal to the SWR of the second power level impedance Z2.