Frequency tuning for modulated plasma systems
AssigneeAdvanced Energy Industries, Inc.
InventorGideon Van Zyl
Life of this patent
Estimating the term…
Abstract
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.
Claims20
A power generation system comprising:
- a high-frequency generator configured to apply power to a plasma chamber at a primary frequency;
- a filter configured to couple to an output of the high-frequency generator to suppress mixing products to limit variation of a time-varying load reflection coefficient presented to the high-frequency generator;
- and
- a frequency-tuning subsystem configured to:
- apply, while the high-frequency generator is applying power at the primary frequency, a probe signal comprising one or more probe frequencies, wherein the one or more probe frequencies are different than the primary frequency, wherein power of the probe signal is lower than power produced at the primary frequency;
- and
- adjust the primary frequency of the high-frequency generator in response to the one or more probe frequencies indicating an improved measure of performance.
A method for automated frequency tuning of a power generation system, the method comprising:
- applying a primary power signal at a primary frequency to a plasma load with a high-frequency generator, either directly or through a matching network;
- applying a probe signal at one or more probe frequencies to the plasma load, wherein the one or more probe frequencies are different than the primary frequency, and wherein power produced at the probe frequencies is lower than power produced at the primary frequency;
- suppressing mixing products with a filter that is separate from the high-frequency generator to reduce variation of a time-varying load reflection coefficient presented to the high-frequency generator;
- and
- adjusting the primary frequency based upon a measure of performance in response to probe signal.
A plasma processing system comprising:
- a plasma chamber;
- a high-frequency generator configured to apply power to a plasma chamber at a primary frequency;
- a low-frequency generator to apply power to the plasma chamber at a low frequency;
- a filter coupled between the high-frequency generator and the plasma chamber that is configured to suppress mixing products of the primary frequency and the low frequency to limit variation of a time-varying load reflection coefficient presented to the high-frequency generator;
- and
- 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 wherein the probe signal comprises one or more probe frequencies that are different than the primary frequency.
Dependencies are inferred from the claim text.