Supervisory control of radio frequency (RF) impedance tuning operation

• US 10,666,206 B2
• Filed: 12/19/2017
• Issued: 05/26/2020
• Est. Priority Date: 08/18/2015
• Status: Active Grant

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Coumou, David J., Reinhardt, Ross, Elner, Yuriy, Gill, Daniel M.
• Primary Examiner(s): Outten, Samuel S
• Application Number:
  US15/846,922
• Publication Number:
  US 20180109230A1
• Time in Patent Office: 889 Days
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/378 A variable capacitor being added in the output circuit, e.g. collector, drain, of an amplifier stage
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/245 with semiconductor devices only

Abstract

A radio frequency (RF) control system including a RF generator having a power amplifier that outputs a RF signal and a controller. A matching network receives the RF signal and generates at least one RF output signal. In a first mode of operation, the controller enables adjustment of the frequency of the RF signal and a tune element of the matching network to achieve an impedance match and in a second mode of operation the controller enables adjustment of only the tune element of the matching network to achieve an impedance match while the frequency is adjusted to a target frequency. The RF controls system operates in a continuous and pulse mode of operation.

Claims

1. A method for controlling a radio frequency (RF) system having a RF generator comprising:

generating a RF signal and varying a frequency of the RF signal; and

in a first mode of operation, when the RF signal is at a first target frequency, adjusting the frequency of the RF signal to adjust an impedance match between the RF generator and a load and adjusting an impedance tuning element of a matching network to provide an impedance match between the RF generator and the load, and

in a second mode of operation, adjusting the impedance tuning element to provide an impedance match between the RF generator and the load and also inhibiting adjusting the frequency of the RF signal to adjust the impedance match, while adjusting the frequency of the RF signal from the first target frequency to a second target frequency.

2. The method for controlling the RF system of claim 1, wherein in the first mode of operation, adjusting the frequency of the RF signal includes adjusting the frequency of the RF signal within a predetermined range about a target frequency.

3. The method for controlling the RF system of claim 2, wherein in the first mode of operation, adjusting the frequency of the RF signal includes adjusting the frequency of the RF signal to vary the impedance match.

4. The method for controlling the RF system of claim 3, wherein in the second mode of operation, adjusting the adjusting the frequency of the RF signal from a first target frequency to a second target frequency without reference to the impedance match.

5. The method for controlling the RF system of claim 4 wherein in the first mode of operation, adjusting the frequency of the RF signal to provide an impedance match includes automatic frequency tuning (AFT).

6. The method for controlling the RF system of claim 1, wherein in the second mode of operation, the frequency of the RF signal from a first target frequency to a second target frequency occurs without reference to the impedance match.

7. The method for controlling the RF system of claim 6, wherein in the first mode of operation, adjusting the frequency of the RF signal to adjust an impedance match includes adjusting the frequency within a predetermined range about a target frequency.

8. The method for controlling the RF system of claim 1 wherein in the first mode of operation, adjusting the impedance tuning element includes adjusting at least one of a load element of the matching network or a tune element of the matching network.

9. The method for controlling the RF system of claim 1 wherein in the second mode of operation, inhibiting adjusting the frequency of the RF signal to provide an impedance match includes disabling automatic frequency tuning (AFT).

10. The method for controlling the RF system of claim 1 further comprising operating the RF generator in a continuous wave mode or a pulse mode.

11. A radio frequency (RF) control system comprising:

a RF generator including a power amplifier that outputs a RF signal, the RF generator generating a RF output signal to a matching network, the matching network receiving the RF signal, the matching network including an impedance tuning element; and

a controller varying a frequency of the RF signal and communicating commands to the matching network to adjust a tuning element that varies an impedance between a RF generator and a load, the controller operating the RF generator in one of two modes of operation, wherein

in a first mode of operation, when the RF signal is at a first target frequency, the controller both applies automatic frequency tuning (AFT) and adjusts the tuning element to vary an impedance match between the RF generator and a load, and

in a second mode of operation, as the frequency of the RF signal is adjusted from the first target frequency to a second target frequency, the controller controls the impedance tuning element to vary the impedance match and inhibits AFT or the controller controls the impedance tuning element to vary the impedance match.

12. The RF control system of claim 11, wherein in the first mode of operation, when the controller applies AFT, the frequency is adjusted within a predetermined range about a target frequency.

13. The RF control system of claim 12, wherein in the second mode of operation, the controller adjusts the frequency to the second target frequency without reference to the impedance match.

14. The RF control system of claim 13, wherein in the first mode of operation, when applying AFT, the controller adjusts the frequency about the target frequency to vary the impedance match.

15. The RF control system of claim 12, wherein when applying AFT, the controller adjusts the frequency about the target frequency to vary the impedance match.

16. The RF control system of claim 11, wherein in the second mode of operation, the controller adjusts the frequency to a target frequency without reference to the impedance match.

17. The RF control system of claim 16, wherein in the first mode of operation, the controller applies AFT to adjust the frequency about the target frequency to vary the impedance match.

18. The RF control system of claim 16, wherein in the second mode of operation, the controller adjusts the frequency to the second target frequency without reference to the impedance.

19. The RF control system of claim 11 wherein the RF generator operates in a continuous wave mode or a pulse mode.

20. The RF control system of claim 11 wherein the tuning element includes a load element and a tune element, and in the first and second modes of operation, the controller adjusts at least one of the load element and the tune element.

21. A controller for a radio frequency (RF) control system operable in one of two modes wherein a first mode of operation, when the RF signal is at a first target frequency, the controller adjusts a frequency of a RF signal to provide an impedance match between an RF generator and a load and adjusts a tuning element to vary the impedance match between the RF generator and the load and a second mode of operation in which the controller adjusts the tuning element to vary an impedance match between the RF generator and the load, while adjusting the frequency of the RF signal from the first target frequency to a second target frequency.

22. The controller of claim 21 wherein in the first mode of operation, the controller adjusts the frequency of the RF signal and the tuning element to vary the impedance match between the RF generator and the load and in the second mode of operation, the controller adjusts only the tuning element to vary the impedance match between the RF generator and the load.

23. The controller of claim 22 wherein the tuning element includes a load element and a tune element, and in the first and second modes of operation, the controller adjusts the load element and the tune element.

24. The controller of claim 23 wherein in the first mode of operation, the controller adjusts the frequency of the RF signal and at least one of the load element or the tune element to vary the impedance match between the RF generator and the load.

25. The controller of claim 21, wherein in the first mode of operation, the controller adjusts the frequency of the RF signal within a predetermined range about a target frequency.

26. The controller of claim 21, wherein in the second mode of operation, the controller adjusts the frequency of the RF signal without reference to the impedance match.

27. A controller for a radio frequency (RF) control system, the RF control system including a RF generator having a power amplifier that outputs a RF signal to a matching network, the matching network receiving the RF signal, the matching network including at least one tuning element that varies an impedance between the RF generator and a load, the controller varying a frequency of the RF signal and communicating commands to the matching network to adjust the tuning element, wherein:

in a first mode of operation, when the RF signal is at a first target frequency, the controller adjusts the frequency of the RF signal and adjusts the tuning element to provide an impedance match between the RF generator and a load, and

in a second mode of operation, the controller adjusts the tuning element to provide an impedance match between the RF generator and the load and also inhibits adjusting the frequency of the RF signal to adjust the impedance match, while adjusting the frequency of the RF signal from the first target frequency to a second target frequency.

28. The controller of claim 27, wherein in the first mode of operation, the frequency is adjusted within a predetermined range about a target frequency.

29. The controller of claim 28, wherein in the second mode of operation, the controller adjusts the frequency without reference to the impedance match.

30. The controller of claim 27, wherein in the second mode of operation, the controller adjusts the frequency without reference to the impedance match.

31. The controller of claim 30, wherein in the first mode of operation, the frequency is adjusted within a predetermined range about a target frequency.

32. The controller of claim 27 wherein in the first mode of operation, the controller adjusts the frequency of the RF signal to provide an impedance match using automatic frequency tuning (AFT).

33. The controller of claim 32 wherein in the second mode of operation, the controller inhibits adjusting the frequency of the RF signal to adjust an impedance match by inhibiting automatic frequency tuning (AFT).

34. The controller of claim 27 wherein the tuning element includes a load element and a tune element, and in the first and second modes of operation, the controller adjusts at least one of the load element and the tune element.

35. The controller of claim 27 wherein the RF generator operates in a continuous wave mode or a pulse mode.