CPC H01J 37/32183 (2013.01) [H01J 2237/3322 (2013.01)] | 17 Claims |
1. A plasma generation system comprising:
a radio frequency generator characterized by a source impedance;
a plasma chamber characterized by a load impedance; and
a matching network coupled to the radio frequency generator and the plasma chamber characterized by a matching network impedance, wherein the matching network together with the plasma chamber is characterized by a combined load impedance;
the matching network further comprising a plurality of impedance control components and a tuning controller, wherein the tuning controller performs a method comprising:
driving the matching network to define a multi-dimensional tuning range for the matching network;
defining a plurality of target impedance values spaced apart throughout the multi-dimensional tuning range;
driving the matching network to produce a plurality of tuning values for the impedance control components for driving the impedance of the matching network proximate to the plurality of target impedance values;
driving the matching network to generate closest measured frame tuning values proximate to the target impedance values; and
computing interpolated tuning values between the measured frame tuning values, including performing an n-dimensional interpolation calculating the proximity of the interpolated impedances using the sum of reflection coefficient and normalized cartesian distance;
storing the tuning values mapped to corresponding matching network impedance values in a tuning database; and
operating the matching network by:
(a) measuring one or more of the matching network impedance, the load impedance, or the combined load impedance;
(b) computing a desired matching network impedance based on the matching network impedance, the load impedance, or the combined load impedance to match the combined load impedance with the source impedance;
(c) looking up a closest matching network impedance value proximate to the desired matching network impedance in the tuning database;
(d) looking up a set of tuning values corresponding to the closest matching network impedance value in the tuning database; and
(e) setting each impedance control component to its respective tuning value.
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