NOISE BASED FREQUENCY TUNING AND IDENTIFICATION OF PLASMA CHARACTERISTICS

摘要

This disclosure describes systems, methods, and apparatus for frequency tuning a power source so as to optimize power delivery to a plasma load as well as systems, methods, and apparatus for identifying characteristics and/or changes in characteristics of a plasma load. In particular, a secondary power signal can be applied concurrently with a primary power signal, the secondary power signal having a substantially lower power level, so as to tune for a global optimum of a measure of performance and/or identifying characteristics and/or changes in characteristics of a plasma load. The secondary power signal can comprise a low level signal that is jointly generated with or combined with the primary power signal, or it can comprise noise either inherent to the primary power signal or added to the primary power signal.

主权项

1. A power generation system configured for automated frequency tuning of power delivered to a plasma load, the power generation system comprising:
a power source to apply a primary power signal at a primary frequency to an output, the output configured for coupling to a plasma load, either directly or through a matching network, the power source is configured to apply one or more secondary power signals at one or more frequencies to the plasma load, wherein power produced at the secondary frequencies is lower than power produced at the primary frequency; a sensor arranged to sense one or more attributes of power delivered to the plasma load to obtain a measure of performance; a global optimum identification module that analyzes the measure of performance and identifies a global optimum frequency as corresponding to a global optimum of the measure of performance; a frequency control module that adjusts the primary frequency towards the identified global optimum frequency corresponding to the global optimum.