GROUND RETURN FOR PLASMA PROCESSES

• US 20100196626A1
• Filed: 02/04/2010
• Published: 08/05/2010
• Est. Priority Date: 02/04/2009
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Kho, Jeffrey A., Anwar, Suhail, Furuta, Gaku, Kurita, Shinichi, Choi, Soo Young, White, John M., Inagawa, Makoto, Tiner, Robin L., Sorensen, Carl A.
• Granted Patent: US 9,382,621 B2
• Time in Patent Office: Days
• US Class Current: 427/569
• CPC Class Codes: C23C 16/4585 Devices at or outside the perimeter of the substrate support, e.g. clamping rings, shrouds
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32174 Circuits specially adapted for controlling the RF discharge
• CPC Class Codes: H01J 37/32568 Relative arrangement or disposition of electrodes; moving means
• CPC Class Codes: H01L 21/67069 for drying etching

Abstract

A method and apparatus for providing an electrically symmetrical ground or return path for electrical current between two electrodes is described. The apparatus includes at least on radio frequency (RF) device coupled to one of the electrodes and between a sidewall and/or a bottom of a processing chamber. The method includes moving one electrode relative to another and realizing a ground return path based on the position of the displaced electrode using one or both of a RF device coupled to a sidewall and the electrode, a RF device coupled to a bottom of the chamber and the electrode, or a combination thereof.

Claims

1. A radio frequency return device for a plasma processing chamber, comprising:

a base having a shaft movably disposed within an opening formed in the base;

a spring coupled between the base and the shaft, the spring comprising a first material made of a metal or metal alloy having an elastic property that is substantially the same at an ambient temperature and a processing temperature of about 200°

C. or greater; and

a second material substantially encasing the first material, the second material being different than the first material.

2. The device of claim 1, wherein the second material is conductive and the first material is coated, wrapped or clad with the second material.

3. The device of claim 1, wherein the first material retains about 85% of the mechanical property at the processing temperature.

4. The device of claim 2, wherein the second material includes a first property at ambient temperature and a second property at the processing temperature, the first property and the second property being substantially different.

5. The device of claim 2, wherein the coating, wrapping or cladding comprises an aluminum material.

6. The device of claim 5, wherein the aluminum material comprises a foil material.

7. The device of claim 1, wherein the elastic property is ultimate tensile strength.

8. The device of claim 1, wherein the first material comprises a nickel-molybdenum-chromium alloy.

9. The device of claim 8, wherein the second material comprises an aluminum material.

10. The device of claim 1, wherein the shaft is coupled to a compression spring disposed in the base.

11. A plasma processing system, comprising:

a chamber; and

at least one electrode disposed within the chamber, the at least one electrode facilitating generation of a plasma within the chamber and movable relative to a second electrode within the chamber, the at least one electrode being maintained electrically coupled while moving relative to the second electrode by one or more flexible contact members, at least one of the one or more flexible contact members comprising a material made of a metal or metal alloy that substantially retains elasticity without plastically deforming when the material reaches a temperature above about 200°

C.

12. The system of claim 11, wherein the material is coated, wrapped or clad with a conductive material.

13. The system of claim 12, wherein the coating, wrapping or cladding comprises aluminum.

14. The system of claim 11, wherein the at least one flexible contact member further comprises:

a base coupled to the at least one electrode; and

a shaft movably disposed in the base, wherein the at least one flexible contact member is coupled to the base at a first end and to the shaft at a second end.

15. The system of claim 14, wherein the base comprises one or more bearing elements between the shaft and an opening formed in the base.

16. The system of claim 14, wherein the shaft is coupled to a compression spring disposed in the base.

17. The system of claim 11, wherein the at least one flexible contact member further comprises:

a spring comprising a first material made of a metal or metal alloy having a having a mechanical property that is substantially the same at an ambient temperature and a processing temperature of about 200°

C. or greater.

18. The system of claim 17, wherein the first material is coated, wrapped or clad with a second material that is different than the first material.

19. The system of claim 18, wherein the second material includes a first property at ambient temperature and a second property at the processing temperature, the first property and the second property being substantially different.

20. The system of claim 11, wherein the chamber includes at least four sidewalls and at least one of the sidewalls includes a transfer port, and wherein the at least one flexible contact member further comprises:

a first plurality of compressible contact members; and

a second plurality of flexible straps.

21. The system of claim 20, wherein the first plurality of compressible contact members are disposed on a side of the first electrode facing the transfer port.

22. A method, comprising:

moving a first electrode in a chamber relative to a second electrode;

applying radio frequency power between the first electrode and the second electrode; and

establishing a selective electrical connection between the first electrode and a grounded component of the chamber based on a distance between the first electrode and the second electrode.

23. The method of claim 22, wherein the first electrode is a substrate support and the grounded component is a sidewall of the processing chamber.

24. The method of claim 22, wherein establishing the selective electrical connection further comprises:

moving the first electrode to a position where the first electrode is electrically disconnected from the grounded component.

25. The method of claim 22, wherein the selective electrical connection comprises a return path for radio frequency current.

26. The method of claim 22, wherein the selective electrical connection is closed when the first electrode is in a distance range proximal to the second electrode.

27. The method of claim 26, wherein the first electrode is movable within the distance range.

28. The method of claim 26, wherein the selective electrical connection is open when the first electrode is moved away from the second electrode.

29. A method, comprising:

applying a radio frequency power between a movable electrode and a fixed electrode disposed in a chamber;

providing a first radio frequency return path to a bottom of the chamber;

displacing the movable electrode relative to the fixed electrode; and

providing a second radio frequency return path to a sidewall of the chamber through one or more compressible contact members.

30. The method of claim 29, wherein providing the first radio frequency return path and the second radio frequency return path is based on a position of the movable electrode relative to the fixed electrode.

31. The method of claim 30, wherein the second radio frequency return path is discontinued as the movable electrode is displaced away from the fixed electrode.

32. The method of claim 29, wherein the one or more compressible contact members are coupled to and movable with the movable electrode.

33. The method of claim 29, wherein the second radio frequency return path is maintained during at least a portion of the displacement of the movable electrode.