US Patent 11804362 Frequency tuning for modulated plasma systems

Plasma processing and power supply systems and methods are disclosed. The plasma processing system comprises a high-frequency generator configured to deliver power to a plasma chamber and a low-frequency generator configured to deliver power to the plasma chamber. A filter is coupled between the plasma chamber and the high-frequency generator, and the filter suppresses mixing products of high frequencies produced by the high-frequency generator and low frequencies produced by the low-frequency generator. The plasma processing system also comprises means for frequency tuning the high-frequency generator using a probe signal that is concurrently applied with the power applied to the plasma chamber at the primary frequency.