US-12620566-B2 - RF reference measuring circuit for a direct drive system supplying power to generate plasma in a substrate processing system

Abstract

A substrate processing system includes a drive circuit, an RF reference measuring circuit, and a make-break connector. The drive circuit generates an RF drive signal at a first RF frequency. The RF reference measuring circuit includes an LC circuit having an input impedance and an output impedance. An output of the LC circuit connects to an RF power meter and a dummy load. The make-break connector connects the drive circuit to one of the RF reference measuring circuit and a processing chamber load including a component of the substrate processing system. An output impedance of the drive circuit matches an impedance of an input impedance of the LC circuit. The output impedance of the drive circuit does not match impedances of the RF power meter and the dummy load. The LC circuit matches the impedance of the drive circuit to the RF power meter and the dummy load.

Inventors

• Maolin Long

Assignees

• LAM RESEARCH CORPORATION

Dates

Publication Date

20260505

Application Date

20240910

Claims (20)

1. 1 . A system comprising: a drive circuit configured to generate a first radio frequency (RF) signal at a first frequency and a second RF signal at a second frequency; and a plurality of inductor-capacitor circuits coupled to the drive circuit to receive the first and second RF signals, wherein the plurality of inductor-capacitor circuits are configured to match an impedance of the drive circuit with a first impedance of a first plurality of components including a first power meter and a first dummy load and with a second impedance of a second plurality of components including a second power meter and a second dummy load.
2. 2 . The system of claim 1 , wherein the drive circuit includes: a clock configured to operate at the first radio frequency or the second radio frequency; a gate driver coupled to the clock, wherein the gate driver has a plurality of outputs; and a half bridge circuit coupled to the plurality of outputs of the gate driver.
3. 3 . The system of claim 1 , wherein the first frequency is within a first frequency range from 1.8 megahertz (MHz) to 2.2 MHz and the second frequency is within a second frequency range from 12.35 MHz to 13.65 MHz.
4. 4 . The system of claim 1 , wherein the plurality of inductor-capacitor circuits include a first inductor-capacitor circuit and a second inductor-capacitor circuit, wherein the first inductor-capacitor circuit is configured to match the impedance of the drive circuit with the first impedance and the second inductor-capacitor circuit is configured to match the impedance of the drive circuit with the second impedance.
5. 5 . The system of claim 4 , wherein the first inductor-capacitor circuit includes: an inductor; a first capacitor coupled to the inductor at a point; a second capacitor coupled to the inductor at the point, wherein the second capacitor is coupled to ground.
6. 6 . The system of claim 4 , wherein the second inductor-capacitor circuit includes: an inductor; a first capacitor coupled in series with the inductor; a second capacitor coupled to the first capacitor, wherein the second capacitor is coupled to ground.
7. 7 . The system of claim 4 , wherein the drive circuit has a first output and a second output, wherein the first inductor-capacitor circuit is coupled via a first connector to the first output and the second inductor-capacitor circuit is coupled via a second connector to the second output.
8. 8 . The system of claim 7 , wherein the first output of the drive circuit is configured to be decoupled from the first inductor-capacitor circuit to be coupled via the first connector to a first plasma processing chamber load, wherein the second output of the drive circuit is configured to be decoupled from the second inductor-capacitor circuit to be coupled via the second connector to a second plasma processing chamber load.
9. 9 . The system of claim 1 , wherein the first plurality of components include a first conductor between the first RF power meter and the first dummy load and the second plurality of components include a second conductor between the second RF power meter and the second dummy load.
10. 10 . A system comprising: a first inductor-capacitor circuit configured to be coupled to a drive circuit to receive a first radio frequency (RF) signal from the drive circuit; and a second inductor-capacitor circuit configured to be coupled to the drive circuit to receive a second RF signal from the drive circuit, wherein when the first and second RF signals are received, the first and second inductor-capacitor circuits are configured to match an impedance of the drive circuit with a first impedance of a first plurality of components including a first power meter and a first dummy load and with a second impedance of a second plurality of components including a second power meter and a second dummy load.
11. 11 . The system of claim 10 , wherein the first inductor-capacitor circuit includes: an inductor; a first capacitor coupled to the inductor at a point; a second capacitor coupled to the inductor at the point, wherein the second capacitor is coupled to ground.
12. 12 . The system of claim 10 , wherein the second inductor-capacitor circuit includes: an inductor; a first capacitor coupled in series with the inductor; a second capacitor coupled to the first capacitor, wherein the second capacitor is coupled to ground.
13. 13 . The system of claim 10 , wherein the first inductor-capacitor circuit is configured to be coupled to the drive circuit via a first connector and the second inductor-capacitor circuit is configured to be coupled to the drive circuit via a second connector.
14. 14 . The system of claim 10 , wherein the first plurality of components include a first conductor between the first RF power meter and the first dummy load and the second plurality of components include a second conductor between the second RF power meter and the second dummy load, wherein the first frequency is within a first frequency range from 1.8 megahertz (MHz) to 2.2 MHz and the second frequency is within a second frequency range from 12.35 MHz to 13.65 MHz.
15. 15 . A method comprising: generating, by a drive circuit, a first radio frequency (RF) signal at a first frequency and a second RF signal at a second frequency; and receiving, by a plurality of inductor-capacitor circuits, the first and second RF signals, wherein the first and second RF signals are received to match an impedance of the drive circuit with a first impedance of a first plurality of components including a first power meter and a first dummy load and with a second impedance of a second plurality of components including a second power meter and a second dummy load.
16. 16 . The method of claim 15 , wherein the drive circuit includes: a clock configured to operate at the first radio frequency or the second radio frequency; a gate driver coupled to the clock, wherein the gate driver has a plurality of outputs; and a half bridge circuit coupled to the plurality of outputs of the gate driver.
17. 17 . The method of claim 15 , wherein the plurality of inductor-capacitor circuits include a first inductor-capacitor circuit and a second inductor-capacitor circuit, wherein the first inductor-capacitor circuit is configured to match the impedance of the drive circuit with the first impedance and the second inductor-capacitor circuit is configured to match the impedance of the drive circuit with the second impedance.
18. 18 . The method of claim 17 , wherein the first inductor-capacitor circuit includes: an inductor; a first capacitor coupled to the inductor at a point; a second capacitor coupled to the inductor at the point, wherein the second capacitor is coupled to ground, wherein the second inductor-capacitor circuit includes: an inductor; a first capacitor coupled in series with the inductor; a second capacitor coupled to the first capacitor, wherein the second capacitor is coupled to ground.
19. 19 . The method of claim 17 , wherein the drive circuit has a first output and a second output, wherein the first inductor-capacitor circuit is coupled via a first connector to the first output and the second inductor-capacitor circuit is coupled via a second connector to the second output, the method comprising: decoupling the first output of the drive circuit from the first inductor-capacitor circuit to couple the first output via the first connector to a first plasma processing chamber load; and decoupling the second output of the drive circuit from the second inductor-capacitor circuit to couple the second output via the second connector to a second plasma processing chamber load.
20. 20 . The method of claim 15 , wherein the first plurality of components include a first conductor between the first RF power meter and the first dummy load and the second plurality of components include a second conductor between the second RF power meter and the second dummy load, wherein the first frequency is within a first frequency range from 1.8 megahertz (MHz) to 2.2 MHz and the second frequency is within a second frequency range from 12.35 MHz to 13.65 MHz.

Description

CLAIM OF PRIORITY This patent application claims the benefit of and priority, under 35 U.S.C. § 120, to U.S. patent application Ser. No. 17/910,785, filed on Sep. 9, 2022, and titled “RF REFERENCE MEASURING CIRCUIT FOR A DIRECT DRIVE SYSTEM SUPPLYING POWER TO GENERATE PLASMA IN A SUBSTRATE PROCESSING SYSTEM”, which is a national stage filing of and claims priority, under 35 U.S.C. § 371, to PCT/US2021/023081, filed on Mar. 19, 2021 and titled “RF REFERENCE MEASURING CIRCUIT FOR A DIRECT DRIVE SYSTEM SUPPLYING POWER TO GENERATE PLASMA IN A SUBSTRATE PROCESSING SYSTEM”, which claims the benefit of and priority, under 35 U.S.C. § 119 (e), to U.S. Provisional Application No. 62/991,960, filed on Mar. 19, 2020, and titled “RF REFERENCE MEASURING CIRCUIT FOR A DIRECT DRIVE SYSTEM SUPPLYING POWER TO GENERATE PLASMA IN A SUBSTRATE PROCESSING SYSTEM”, all of which are incorporated by reference herein in their entirety. FIELD The present disclosure relates to substrate processing systems and more particularly to a radio frequency (RF) reference measuring circuit to measure an RF reference generated by a direct drive system supplying RF power to a substrate processing system. BACKGROUND The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Substrate processing systems are typically used to etch thin film on substrates such as semiconductor wafers. Etching usually includes either wet chemical etching or dry etching. Dry etching may be performed using plasma generated by inductively-coupled plasma (ICP). A magnetic field is generated by one or more inductive coils arranged outside of a processing chamber adjacent to a dielectric window. Process gas flowing inside the processing chamber is ignited by the magnetic field to create plasma. In some applications, RF bias power may also be supplied to an electrode in the substrate support. The frequency of the RF plasma power or RF bias power can be varied to provide additional process control. In addition, a magnitude or level of the RF plasma power or the RF bias power can be varied during processing to provide additional process control. Changes in the RF plasma power or level and/or the RF bias power or level can cause changes in the impedance seen by the drive circuit. When an impedance mismatch occurs between the load and the drive circuit, power is reflected, which is inefficient. SUMMARY A substrate processing system comprises a drive circuit, an RF reference measuring circuit, and a make-break connector. The drive circuit is configured to generate an RF drive signal at a first RF frequency. The RF reference measuring circuit includes an LC circuit having an input impedance and an output impedance. An output of the LC circuit is configured to connect to an RF power meter and a dummy load. The make-break connector is configured to connect the drive circuit to one of the RF reference measuring circuit and a processing chamber load including a component of the substrate processing system. An output impedance of the drive circuit matches an impedance of an input impedance of the LC circuit. The output impedance of the drive circuit does not match impedances of the RF power meter and the dummy load. The LC circuit is configured to match the impedance of the drive circuit to the RF power meter and the dummy load. In other features, the RF reference measuring circuit includes a first conductor connected to an output of the LC circuit and the RF power meter is connected to the first conductor. In other features, the RF reference measuring circuit includes a second conductor connected to an output of the RF power meter and the dummy load is connected to the second conductor. In other features, the output impedance of the drive circuit, and the input impedance of the LC circuit are in a range from 0.1Ω to 10Ω. In other features, the output impedance of the drive circuit, and the input impedance of the LC circuit are in a range from 0.5Ω to 2Ω. In other features, the output impedance of the LC circuit and impedances of the RF power meter, the dummy load, the first conductor and the second conductor are in a range from 20Ω to 100Ω. In other features, the output impedance of the LC circuit and the impedances of the RF power meter, the dummy load, the first conductor and the second conductor are in a range from 45Ω to 55Ω. In other features, the LC circuit includes a first connector connected to the make-break connector, an inductor having one end connected to the first connector, a first capacitor connected in series with an opposite end of the inductor, and a second capacitor connected in parallel between the opposite end of the induc