US 12,283,463 B2
Systems and methods for multi-level pulsing in RF plasma tools
Ying Wu, Livermore, CA (US); Maolin Long, Santa Clara, CA (US); John Drewery, San Jose, CA (US); and Vikram Singh, Santa Clara, CA (US)
Assigned to Lam Research Corporation, Fremont, CA (US)
Appl. No. 17/605,982
Filed by Lam Research Corporation, Fremont, CA (US)
PCT Filed Apr. 24, 2020, PCT No. PCT/US2020/029900
§ 371(c)(1), (2) Date Oct. 22, 2021,
PCT Pub. No. WO2020/233129, PCT Pub. Date Nov. 5, 2020.
Claims priority of provisional application 62/840,335, filed on Apr. 29, 2019.
Prior Publication US 2022/0216038 A1, Jul. 7, 2022
Int. Cl. H01J 37/32 (2006.01); H03K 3/017 (2006.01)
CPC H01J 37/32183 (2013.01) [H01J 37/32146 (2013.01); H01J 37/32174 (2013.01); H03K 3/017 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for generating a multi-state plasma impedance, comprising:
receiving, from a processor by a first radio frequency (RF) generator and a second RF generator, a synchronization signal having a plurality of cycles that repeat periodically;
generating a first RF signal by the first RF generator, wherein the first RF signal includes at least two parameter levels within one of the plurality of cycles;
generating a second RF signal by the second RF generator, wherein the second RF signal includes at least three parameter levels within the one of the plurality of cycles; and
modifying a time of transition between the at least two parameter levels or a time of transition among the at least three parameter levels based on a number of plasma impedance states to be achieved.
 
9. A controller system for generating a multi-state plasma impedance, comprising:
a first processor of a first radio frequency (RF) generator, wherein the first processor is configured to receive a synchronization signal having a plurality of cycles that repeat periodically,
wherein the first processor is configured to control a first RF power supply of the first RF generator to generate a first RF signal, wherein the first RF signal includes at least two parameter levels within one of the plurality of cycles; and
a second processor of a second RF generator, wherein the second processor is configured to receive the synchronization signal,
wherein the second processor is configured to control a second RF power supply of the second RF generator to generate a second RF signal, wherein the second RF signal includes at least three parameter levels within the one of the plurality of cycles,
wherein the first processor is configured to control the first RF power supply to modify a time of transition between the at least two parameter levels or the second processor is configured to control the second RF power supply to modify a time of transition among the at least three parameter levels based on a number of plasma impedance states to be achieved.
 
17. A plasma system for generating a multi-state plasma impedance, comprising:
a first radio frequency (RF) generator configured to generate a first RF signal; and
a second RF generator configured to generate a second RF signal,
wherein each of the first and second RF generators are configured to receive a synchronization signal having a plurality of cycles that repeat periodically,
wherein the first RF signal includes at least two parameter levels within one of the plurality of cycles,
wherein the second RF signal includes at least three parameter levels within the one of the plurality of cycles,
wherein the first RF generator is configured to modify a time of transition between the at least two parameter levels or the second RF generator is configured to modify a time of transition among the at least three parameter levels based on a number of plasma impedance states to be achieved.