# US 10,373,794 B2 · Systems and methods for filtering radio frequencies from a signal of a thermocouple and controlling a temperature of an electrode in a plasma chamber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,373,794 B2 - Document ID: US10373794B2 - Status: Granted - Kind: B2 - Application number: 14/965,030 - Filed: 2015-12-10 - Published: 2017-05-04 - Granted: 2019-08-06 - Earliest claimed: 2015-10-29 - Assignees: Lam Research Corporation - Applicants: Lam Research Corporation - Inventors: Vince Burkhart; Christopher Ramsayer; Mohan Thilagaraj - Web page: https://patentgrep.com/patent/US10373794B2 ## CPC - H01J 37/04: Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement {(H01J37/32009, H01J37/32623, H01J37/3266, H01J37/32697 take precedence; electron or ion-optical systems for localised treatment of objects H01J37/3007)} - H01J 37/244: Detectors; Associated components or circuits therefor - H01J 37/32522: {Temperature} - H01J 37/32935: {Monitoring and controlling tubes by information coming from the object and/or discharge} - H05B 1/0233: {for semiconductors manufacturing} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A circuit including a first filter assembly and a controller. The first filter assembly is implemented on a printed circuit board. The first filter assembly includes a first filter and a second filter. The first filter receives a first signal from a first sensor, prevents passage of a first portion of the first signal and outputs a second signal. The first portion of the first signal is at a first radio frequency. A second portion of the first signal is indicative of a first temperature of a first electrode in a plasma chamber. The second filter receives the second signal and prevents passage of a portion of the second signal. The portion of the second signal is at a second radio frequency. The second radio frequency is less than the first radio frequency. The controller adjusts a temperature of the first electrode based on an output of the second filter. ## Claims ### Claim 1 A circuit comprising: a first filter assembly implemented on a printed circuit board, the first filter assembly comprising a first filter configured to (i) receive a first signal from a first sensor, (ii) prevent passage of a first portion of the first signal, and (iii) output a second signal, wherein the first portion of the first signal is at a first radio frequency, and wherein a second portion of the first signal is indicative of a first temperature of a first electrode in a plasma chamber, and a second filter configured to (i) receive the second signal, and (ii) prevent passage of a portion of the second signal, wherein the portion of the second signal is at a second radio frequency, and wherein the second radio frequency is less than the first radio frequency; and a controller configured to adjust a temperature of the first electrode based on an output of the second filter. ### Claim 2 (depends on 1) The circuit of claim 1, wherein: the first filter is a band stop filter and permits passage of the portion of the second signal; and the second filter is a low pass filter. ### Claim 3 (depends on 1) The circuit of claim 1, wherein the controller is configured to control operation of a cooling device to maintain a temperature of the first filter assembly at a predetermined temperature. ### Claim 4 (depends on 3) The circuit of claim 3, wherein the cooling device is a fan. ### Claim 5 (depends on 3) The circuit of claim 3, wherein the cooling device is a valve or a pump. ### Claim 6 (depends on 3) The circuit of claim 3, wherein the controller is configured to control flow of a fluid through a block thermally connected to the first filter assembly to maintain the temperature of the first filter assembly at a predetermined temperature. ### Claim 7 (depends on 3) The circuit of claim 3, wherein: the first filter assembly comprises a second sensor and a third sensor; an output of the second sensor is indicative of a temperature at an input of the first filter assembly; an output of the third sensor is indicative of a temperature at an output of the first filter assembly; and the controller is configured to control the cooling device based on the output of the second sensor and the output of the third sensor. ### Claim 8 (depends on 1) The circuit of claim 1, further comprising a third filter separate from the first filter assembly and configured to receive the output of the second filter, wherein: the controller is configured to adjust the temperature of the first electrode based on an output of the third filter; and the third filter includes thermocouple lines wrapped around a core. ### Claim 9 (depends on 1) The circuit of claim 1, further comprising a second filter assembly comprising: a third filter configured to filter an output of the second filter; and a fourth filter configured to generate an output based on a second signal from the first sensor, and wherein the controller is configured to (i) receive an alternating current based on the output of the fourth filter, and (ii) adjust a temperature of the first electrode based on an output of the third filter. ### Claim 10 (depends on 1) The circuit of claim 1, further comprising an isolation device configured to isolate a direct current from (i) thermocouple lines associated with the first sensor, or (ii) the controller. ### Claim 11 (depends on 1) A system comprising: the circuit of claim 1; and the first electrode configured to receive a first radio frequency signal and a second radio frequency signal, wherein the first radio frequency signal is at a first radio frequency, the second radio frequency signal is at a second radio frequency, the second radio frequency is less than the first radio frequency, the first filter prevents passage of the first radio frequency and permits passage of the second radio frequency, and the second filter prevents passage of the second radio frequency. ### Claim 12 (depends on 11) The system of claim 11, wherein the second filter prevents passage of signals at frequencies above a cut-off frequency including the first radio frequency. ### Claim 13 A circuit comprising: a first filter assembly comprising a band stop filter configured to (i) receive a first signal from a first sensor, (ii) prevent passage of a first portion of the first signal, and (iii) and output a second signal, wherein the first portion of the first signal is at a first radio frequency, and wherein a second portion of the first signal is indicative of a first temperature of a first electrode in a plasma chamber, and a low pass filter configured to (i) receive the second signal, and (ii) prevent passage of a portion of the second signal, wherein the portion of the second signal is at a second radio frequency, and wherein the second radio frequency is less than the first radio frequency; and a controller configured to adjust a temperature of the first electrode based on an output of the low pass filter. ### Claim 14 (depends on 13) The circuit of claim 13, wherein: the controller is configured to control flow of a fluid through a block thermally connected to the first filter assembly to maintain the temperature of the first filter assembly at a predetermined temperature; the first filter assembly comprises a second sensor and a third sensor; an output of the second sensor is indicative of a temperature at an input of the first filter assembly; an output of the third sensor is indicative of a temperature at an output of the first filter assembly; and the controller is configured to control a cooling device based on the output of the second sensor and the output of the third sensor to maintain the first filter assembly at a predetermined temperature. ### Claim 15 (depends on 13) The circuit of claim 13, further comprising a second filter assembly separate from the first filter assembly, wherein: the second filter assembly comprises a third filter configured to filter an output of the low pass filter, and a fourth filter configured to generate an output based on a second signal from the first sensor; and the controller is configured to (i) receive an alternating current based on the output of the fourth filter, and (ii) adjust a temperature of the first electrode based on an output of the third filter. ### Claim 16 (depends on 1) The circuit of claim 1, wherein the controller is configured to adjust the temperature of the first electrode by adjusting an amount of current supplied to the first electrode. ### Claim 17 (depends on 1) The circuit of claim 1, further comprising a plurality of relays, wherein: the controller is configured to adjust the temperature of the first electrode by adjusting an amount of current supplied to one or more of the plurality of relays; and the first electrode receives current from the plurality of relays. ### Claim 18 (depends on 1) The circuit of claim 1, wherein the second filter receives the second signal from the first filter. ### Claim 19 (depends on 1) The circuit of claim 1, wherein the first sensor is a thermocouple.