Patent ID: 11972927
Assignee: ADVANCED ENERGY INDUSTRIES, INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 4:
5. A plasma processing system comprising:
a high-frequency generator configured to deliver power to a plasma chamber;
a wideband measurement system configurable with a filter bandwidth that exceeds a modulation frequency of the plasma, the wideband measurement system providing an indication of an impedance presented to the high-frequency generator; and
a frequency-tuning subsystem configured to adjust a frequency of the high-frequency generator to adjust the impedance presented to the high-frequency generator;
wherein the frequency-tuning subsystem is configured to adjust the frequency of the power by:
delivering power at a selected frequency for at least 90% of a total time;
delivering power at a test frequency during test periods, wherein the test periods are no longer than 10% of the total time, wherein a value of the test frequency changes from test period to test period; and
changing a value of the selected frequency to the value of the test frequency if the impedance presented to the high-frequency generator is closer to a target impedance when the high-frequency generator is delivering power at the test frequency.