# US 2021/0241996 A1 · Spatial monitoring and control of plasma processing environments > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241996 A1 - Document ID: US20210241996A1 - Status: Published application - Kind: A1 - Application number: 17/171,164 - Filed: 2021-02-09 - Published: 2021-08-05 - Earliest claimed: 2017-11-17 - Assignees: Advanced Energy Industries, Inc. - Applicants: Advanced Energy Industries, Inc. - Inventors: Daniel Carter; Kevin Fairbairn; Denis Shaw; Victor Brouk - Web page: https://patentgrep.com/patent/US20210241996A1 ## CPC - H01J 37/32137: {controlling of the discharge by modulation of energy} - H01J 37/32174: {Circuits specially adapted for controlling the RF discharge} - H01J 37/32082: {Radio frequency generated discharge (H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence)} - H01J 37/32412: {Plasma immersion ion implantation} - H01J 37/32477: {characterised by the means for protecting vessels or internal parts, e.g. coatings} - H01J 37/32559: {Protection means, e.g. coatings} - H01J 37/32568: {Relative arrangement or disposition of electrodes; moving means} - H01J 37/32706: {Polarising the substrate} - H01J 37/32935: {Monitoring and controlling tubes by information coming from the object and/or discharge} - H10P 72/0434: {mainly by convection} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract Systems and methods for plasma processing are disclosed. An exemplary system may include a plasma processing chamber comprising a source to produce a plasma in the processing chamber and at least two bias electrodes arranged within the plasma processing chamber to control plasma sheaths proximate to the bias electrodes. A chuck is disposed to support a substrate, and a source generator is coupled to the plasma electrode. At least one bias supply is coupled to the at least two bias electrodes, and a controller is included to control the at least one bias supply to control the plasma sheaths proximate to the bias electrodes. ## Claims ### Claim 1 A method for plasma processing, the method comprising: sustaining a plasma in a plasma processing chamber by inductively coupling a primary inductor to n secondary inductors so current that passes through each of the n secondary inductors results from mutual inductance through the plasma with the primary inductor; applying an asymmetric periodic voltage waveform to the plasma processing chamber with a bias supply; and adjusting at least one of current though one or more of the n secondary inductors or one or more characteristics of the asymmetric periodic voltage waveforms to alter a spatial distribution of the plasma. ### Claim 2 (depends on 1) The method of claim 1, comprising: applying the asymmetric periodic voltage waveform to each of a plurality of zones with a plurality of corresponding bias supplies. ### Claim 3 (depends on 2) The method of claim 2, comprising: monitoring at least one characteristic of the power that is applied by each of the corresponding bias supplies, and wherein the adjusting is based upon the monitoring. ### Claim 4 (depends on 1) The method of claim 1, comprising: calculating ion current in a zone of the plasma processing chamber based upon at least one characteristic of the power that is applied by the bias supply; wherein the adjusting is based upon the calculated ion current in the zone. ### Claim 5 (depends on 1) The method of claim 1, comprising: applying an asymmetric periodic voltage waveform to each of a plurality of zones in the plasma processing chamber with a corresponding bias supply; and calculating ion current in each of the plurality of zones in the plasma processing chamber based upon at least one characteristic of the power that is applied by each of the plurality of bias supplies. ### Claim 6 (depends on 5) The method of claim 5, wherein the adjusting comprises adjusting density of the plasma proximate to each of the plurality of zones by adjusting current though one or more of the n secondary inductors based upon at least one characteristic of the power that is applied by each of the plurality of bias supplies. ### Claim 7 (depends on 5) The method of claim 5, wherein the adjusting comprises adjusting density of the plasma proximate to each of the plurality of zones by adjusting one or more characteristics of the asymmetric periodic voltage waveforms. ### Claim 8 A non-transitory computer-readable medium comprising instructions stored thereon, for at least one of execution by a processor or for configuring a field programmable gate array, to perform plasma processing, the instructions comprising instructions to: maintain a plasma in a plasma processing chamber by controlling current in n secondary inductors, wherein n is greater than or equal to one and the current in the n secondary inductors results from mutual inductance through the plasma with the primary inductor; apply an asymmetric periodic voltage waveform to the plasma processing chamber with a bias supply; and adjust at least one of: current though one or more of the n secondary inductors; or one or more characteristics of the asymmetric periodic voltage waveform to alter a spatial distribution of the plasma. ### Claim 9 (depends on 8) The non-transitory computer-readable medium of claim 8, comprising instructions to: monitor at least one characteristic of the power that is applied by each of the corresponding bias supplies, and wherein the adjustment is based upon the monitoring. ### Claim 10 (depends on 8) The non-transitory computer-readable medium of claim 8, comprising instructions to: calculate ion current in a zone of the plasma processing chamber based upon at least one characteristic of the power that is applied by the bias supply; and wherein the instructions to adjust include instructions to adjust based upon the calculated ion current in the zone. ### Claim 11 (depends on 8) The non-transitory computer-readable medium of claim 8, comprising instructions to: apply an asymmetric periodic voltage waveform to each of a plurality of zones in the plasma processing chamber with a corresponding bias supply; and calculate ion current in each of the plurality of zones in the plasma processing chamber based upon at least one characteristic of the power that is applied by each of the plurality of bias supplies. ### Claim 12 (depends on 11) The non-transitory computer-readable medium of claim 11, wherein the instructions to adjust comprise instructions to adjust a density of the plasma proximate to each of the plurality of zones by adjusting current though one or more of the n secondary inductors based upon the calculated ion current in one or more of the plurality of zones. ### Claim 13 (depends on 11) The non-transitory computer-readable medium of claim 11, wherein the instructions to adjust comprise instructions to adjust a density of the plasma proximate to each of the plurality of zones by adjusting one or more characteristics of the asymmetric periodic voltage waveforms based upon the calculated ion current in one or more of the plurality of zones. ### Claim 14 A system for controlling a plasma in a processing chamber, the system comprising: a source generator; a primary inductor coupled to the source generator to excite the plasma when power is actively applied by the source generator to the primary inductor; n secondary inductors positioned relative to the primary inductor so that current that passes through the n secondary inductors results from mutual inductance through the plasma with the primary inductor, wherein n is greater than or equal to one; a terminating element coupled to each of the n secondary inductors to form n terminating elements, the terminating element affecting the current through a corresponding secondary inductor to affect the spatial distribution of the plasma; at least one electrical plane arranged within the plasma processing chamber to control a plasma sheath proximate to the at least one electrical plane; at least one bias supply coupled to the at least one electrical plane; and at least one controller coupled to the at least one bias supply to apply an asymmetric periodic voltage waveform to the at least one electrical plane to control the plasma sheath proximate to the electrical plane. ### Claim 15 (depends on 14) The system of claim 14, wherein the terminating element is an impedance-adjustable terminating element to enable current through the at least one secondary inductor to be controlled. ### Claim 16 (depends on 15) The system of claim 15, wherein the terminating element is configured to be adjustable by the at least one controller. ### Claim 17 (depends on 16) The system of claim 16, wherein the at least one controller is configured to control the terminating element based upon an indication of a level of ion current in the plasma proximate to the at least one electrical plane. ### Claim 18 (depends on 17) The system of claim 17 wherein the indication of the level of ion current is obtained from at least one characteristic of power that is applied by the at least one bias supply to the at least one electrical plane. ### Claim 19 (depends on 17) The system of claim 17, comprising at least one sensor coupled to at least one of the n terminating elements, wherein the controller adapted to regulate the current through the at least one of the n terminating elements responsive to a signal from the at least one sensor to regulate the plasma density. ### Claim 20 (depends on 19) The system of claim 19, wherein the at least one sensor includes a current sensor and wherein the impedance-adjustable terminating elements include a variable capacitor.