US 11,929,235 B2
Systems and methods for tuning a MHz RF generator within a cycle of operation of a kHZ RF generator
Arthur M. Howald, Livermore, CA (US); and John C. Valcore, Jr., Fremont, CA (US)
Assigned to Lam Research Corporation, Fremont, CA (US)
Appl. No. 17/616,987
Filed by Lam Research Corporation, Fremont, CA (US)
PCT Filed May 6, 2020, PCT No. PCT/US2020/031723
§ 371(c)(1), (2) Date Dec. 6, 2021,
PCT Pub. No. WO2020/247138, PCT Pub. Date Dec. 10, 2020.
Claims priority of provisional application 62/858,538, filed on Jun. 7, 2019.
Prior Publication US 2022/0165543 A1, May 26, 2022
Int. Cl. H01J 37/32 (2006.01)
CPC H01J 37/32155 (2013.01) [H01J 37/32183 (2013.01)] 32 Claims
OG exemplary drawing
 
1. A tuning method comprising:
accessing, for a first set of one or more cycles of operation of a first radio frequency generator, a plurality of reflection parameter values associated with a second radio frequency generator;
calculating a plurality of load impedance parameter values from the plurality of reflection parameter values by applying the plurality of reflection parameter values to a computer-based model of at least a portion of a radio frequency path, wherein the radio frequency path is between the second radio frequency generator and an electrode of a plasma chamber;
receiving a plurality of frequency modulation parameters of a radio frequency signal to be generated by the second radio frequency generator;
determining values of the plurality of frequency modulation parameters by applying the plurality of load impedance parameter values to the computer-based model, wherein the values of the plurality of frequency modulation parameters are determined to minimize a reflection coefficient parameter at an input of the computer-based model; and
controlling the second radio frequency generator according to the values of the plurality of frequency modulation parameters during a second set of one or more cycles of operation of the first radio frequency generator.