AUXILIARY CIRCUIT IN RF MATCHING NETWORK FOR FREQUENCY TUNING ASSISTED DUAL-LEVEL PULSING

• US 20180294566A1
• Filed: 04/02/2018
• Published: 10/11/2018
• Est. Priority Date: 04/07/2017
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Wang, Yuhou, Sato, Arthur H., Wu, Ying, Paterson, Alexander Miller
• Granted Patent: US 10,879,044 B2
• Time in Patent Office: Days
• CPC Class Codes: H01J 37/32183 Matching circuits
• CPC Class Codes: H01Q 5/335 at the feed, e.g. for impedance matching

Abstract

A radio frequency (RF) matching circuit control system includes an RF matching circuit including a plurality of tunable components. The RF matching circuit is configured to receive an input signal including at least two pulsing levels from an RF generator, provide an output signal to a load based on the input signal, and match an impedance associated with the input signal to impedances of the load. A controller is configured to determine respective impedances of the load for the at least two pulsing levels of the input signal and adjust operating parameters of the plurality of tunable components to align a frequency tuning range of the RF matching circuit with the respective impedances of the load for the at least two pulsing levels to match the impedance associated with the input signal to the respective impedances.

Claims

1. A radio frequency (RF) matching circuit control system, comprising:

an RF matching circuit including a plurality of tunable components, wherein the RF matching circuit is configured to

receive an input signal from an RF generator, wherein the input signal includes at least two pulsing levels,

provide an output signal to a load based on the input signal, and match an impedance associated with the input signal to impedances of the load; and

a controller configured to

determine respective impedances of the load for the at least two pulsing levels of the input signal, and

adjust operating parameters of the plurality of tunable components to align a frequency tuning range of the RF matching circuit with the respective impedances of the load for the at least two pulsing levels to match the impedance associated with the input signal to the respective impedances.

2. The RF matching circuit control system of claim 1, wherein the operating parameters include:

a first operating parameter corresponding to at least one of a first capacitance of a first capacitor and a second capacitance of a second capacitor of the RF matching circuit; and

a second operating parameter corresponding to a third capacitance of a third capacitor.

3. The RF matching circuit control system of claim 2, wherein the first capacitor corresponds to a shunt capacitor connected between the input signal and ground.

4. The RF matching circuit control system of claim 3, wherein the second capacitor corresponds to a series capacitor connected between the input signal and the load.

5. The RF matching circuit control system of claim 4, wherein the third capacitor is connected between (i) an end of the second capacitor connected to the load and (ii) ground.

6. The RF matching circuit control system of claim 5, wherein the operating parameters further include a third operating parameter corresponding to an inductance value of an inductor.

7. The RF matching circuit control system of claim 6, wherein the inductor is connected in parallel with the third capacitor.

8. The RF matching circuit control system of claim 5, wherein adjusting the first operating parameter shifts the frequency tuning range in a translational direction.

9. The RF matching circuit control system of claim 5, wherein adjusting the second operating parameter shifts the frequency tuning range in a rotational direction.

10. The RF matching circuit control system of claim 5, wherein, to adjust the first operating parameter, the controller is configured to (i) determine respective values of the first capacitance and the second capacitance to reduce a reflected power associated with the impedance of the load for a first pulsing level of the at least two pulsing levels and (ii) adjust at least one of the first capacitor and the second capacitor based on the determined respective values.

11. The RF matching circuit control system of claim 5, wherein, to adjust the second operating parameter, the controller is configured to (i) determine a value of the third capacitance to reduce a reflected power associated with the impedance of the load for a second pulsing level of the at least two pulsing levels and (ii) adjust the third capacitor to the determined value of the third capacitance.

12. A substrate processing system comprising the RF matching circuit control system of claim 1.

13. The RF matching circuit control system of claim 1, wherein the load corresponds to at least one of an electrode, an inductive coil structure, and plasma within a substrate processing chamber.

14. A method for performing impedance matching in a substrate processing system, the method comprising:

using an RF matching circuit including a plurality of tunable components, receiving an input signal from an RF generator, wherein the input signal includes at least two pulsing levels,

providing an output signal to a load based on the input signal, and

matching an impedance associated with the input signal to impedances of the load;

determining respective impedances of the load for the at least two pulsing levels of the input signal; and

adjusting operating parameters of the plurality of tunable components to align a frequency tuning range of the RF matching circuit with the respective impedances of the load for the at least two pulsing levels to match the impedance associated with the input signal to the respective impedances.

15. The method of claim 14, wherein the operating parameters include:

a first operating parameter corresponding to at least one of a first capacitance of a first capacitor and a second capacitance of a second capacitor of the RF matching circuit; and

a second operating parameter corresponding to a third capacitance of a third capacitor.

16. The method of claim 15, wherein the first capacitor corresponds to a shunt capacitor connected between the input signal and ground.

17. The method of claim 16, wherein the second capacitor corresponds to a series capacitor connected between the input signal and the load.

18. The method of claim 17, wherein the third capacitor is connected between (i) an end of the second capacitor connected to the load and (ii) ground.

19. The method of claim 18, further comprising connecting an inductor in parallel with the third capacitor.

20. The method of claim 18, wherein adjusting the first operating parameter shifts the frequency tuning range in a translational direction and adjusting the second operating parameter shifts the frequency tuning range in a rotational direction.