Segmented electrode apparatus for plasma processing

• US 6,863,020 B2
• Filed: 07/08/2002
• Issued: 03/08/2005
• Est. Priority Date: 01/10/2000
• Status: Expired due to Fees

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Mitrovic, Andrej S., Johnson, Wayne L.
• Primary Examiner(s): Hassanzadef, P.
• Assistant Examiner(s): CROWELL, ANNA M
• Application Number:
  US10/189,425
• Publication Number:
  US 20020170676A1
• Time in Patent Office: 974 Days
• Field of Search: 118/715, 118/723.E, 118/723.R, 118/723.MW, 118/723.I, 118/723.ER, 156/345.34, 156/345.33, 156/345.36, 156/345.43, 156/345.44, 156/345.45, 156/345.47, 156/345.46
• US Class Current: 118/723.00E
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32532 Electrodes
• CPC Class Codes: H01J 37/32568 Relative arrangement or disposition of electrodes; moving means

Abstract

An electrode assembly (50) and an associated plasma reactor system (10) and related methods for a variety of plasma processing applications. The electrode assembly provides control of a plasma density profile (202) within an interior region (30) of a plasma reactor chamber (20). The electrode assembly includes an upper electrode (54) having a lower surface (54L), an upper surface (54U) and an outer edge (54E). The lower surface of the upper electrode faces interior region of the plasma chamber housing the plasma (200), and thus interfaces with the plasma. The electrode assembly further includes a segmented electrode (60) arranged proximate to and preferably substantially parallel with the upper surface of the upper electrode. The segmented electrode comprises two or more separated electrode segments (62a, 62b, . . . 62n), each having an upper and lower surface. Each electrode segment is spaced apart from the upper electrode upper surface by a corresponding controlled gap (Ga, Gb, . . . Gn). The electrode assembly may further include one or more actuators (110) attached to one or more electrode segments at the upper surface of the one or more electrode segments. The actuators allow for movement of the one or more electrode segments to adjust one or more of the controlled gaps. The adjustable controlled gaps allow for controlling the shape of the plasma density profile within the interior region of the chamber, thereby allowing for a desired plasma process result.

Claims

1. An electrode assembly for providing a controlled RF electric field profile within a region capable of supporting a plasma, comprising:

a) an upper electrode having a lower surface, an upper surface and an outer edge, wherein the region capable of supporting a plasma is adjacent said upper electrode lower surface; and

b) a segmented electrode arranged proximate to said upper electrode upper surface, comprising two or more separated electrode segments each having an upper and lower surface, at least lower surfaces of said two or more separated electrode segments being spaced apart from said upper electrode upper surface by corresponding controlled gaps,

said segmented electrode and said upper electrode being sealed so that said segmented electrode is isolated from said plasma by said upper electrode.

2. An electrode assembly according to claim 1, further including one or more actuators attached to one or more electrode segments at said upper surface of said one or more electrode segments, for moving said one or more electrode segments to adjust one or more of said controlled gaps.

3. An electrode assembly according to claim 2, wherein said actuators are piezoelectric transducers.

4. An electrode assembly according to claim 1, further including first corrugations and first spaces on said lower surfaces of said electrode segments, and second corrugations and second spaces on said upper surface of said upper electrode, wherein said first corrugations are aligned with said second spaces.

5. An electrode assembly according to claim 2, further including first corrugations and first spaces on said lower surfaces of said electrode segments, and second corrugations and second spaces on said upper surface of said upper electrode, wherein said first corrugations are aligned with said second spaces.

6. An electrode according to claim 4 or 5, wherein said second spaces are sized slightly larger than said first corrugations.

7. An electrode assembly according to claim 5, wherein said one or more actuators protrude into corresponding one or more first corrugations.

8. An electrode assembly according to claim 2, further including an actuator controller system electronically connected to said one or more actuators, for controlling said actuators.

9. An electrode assembly according to claim 8, further including one or more segment electrode RF power supply systems electronically connected to said one or more segment electrodes through respective one or more segment electrode RF feeds.

10. An electrode assembly according to claim 9, further including a main RF power supply system electronically connected to said upper electrode through a main RF feed.

11. An electrode assembly according to claim 10, further including an RF control system electronically connected to said upper electrode and one or more segment electrode RE power supply systems.

12. An electrode assembly according to claim 11, further including a main control system electronically connected to said actuator controller system and said RF control system.

13. An electrode assembly according to claim 12, further including a pressure sensor in the chamber and a temperature sensor on the segmented electrode assembly, both electronically connected to said main control system.

14. An electrode assembly according to claim 13, further including a database electronically connected to said main control system, containing information pertaining to a plurality of parameter values corresponding to a variety of plasma density profiles.

15. An electrode assembly according to claim 10 wherein said main RF power supply system and said segment electrode RF power supply systems include a signal generator, a gain stage, a phase shifter, a match network, and a bandpass filter.

16. An electrode assembly according to claim 1, 2, 4 or 5, further including an insulator ring surrounding said outer edge of said upper electrode.

18. An electrode assembly according to claim 1, 2, 4 or 5, wherein one or more of said controlled gaps includes a solid dielectric layer.

19. An electrode according to claim 1, wherein one or more of said controlled gaps includes a solid dielectric layer that fills the entirety of said one or more controlled gaps.

20. An electrode assembly according to claim 1, 2, 4 or 5, as arranged in a plasma chamber having chamber sidewalls and an interior region with an insulator ring arranged within the interior region adjacent the chamber sidewalls, the electrode assembly further including a modular housing enclosing said two or more electrode segments and said outer edge and said upper surface of said upper electrode, and also including no more than two vacuum seals, with a first vacuum seal arranged between said insulator ring and said chamber sidewalls, and a second vacuum seal arranged between said insulator ring and said modular housing.

21. An electrode assembly according to claim 1, 2, 4 or 5, wherein said two or more electrode segments are wedge-shaped and symmetrically arranged in a plane.

22. An electrode assembly according to claim 21, wherein the number of wedge-shaped electrode segments is four.

23. An electrode assembly according to claim 1, 2, 4 or 5, wherein said two or more electrode segments are circular-shaped.

24. An electrode assembly according to claim 1, 2, 4 or 5, wherein said upper electrode includes a gas conduit leading from said upper electrode upper surface to one or more gas injection holes on said upper electrode lower surface.

25. A plasma reactor system comprising:

a) a plasma chamber having a lower wall and chamber sidewalls;

b) a substrate support member having a support surface for supporting a substrate, arranged adjacent said lower wall; and

c) an electrode assembly according to claim 1 or 4, arranged adjacent said substrate support member and within said chamber sidewalls such that said lower surface of said upper electrode and a surface of said substrate are substantially parallel and form, in combination with said chamber sidewalls, an interior region capable of containing a plasma.

26. A plasma reactor system according to claim 25, further including a cooling system in fluid communication with said electrode assembly, for flowing fluid through said electrode assembly.

27. A plasma reactor system according to claim 26, further including a vacuum system in pneumatic communication with said interior region, for regulating the pressure of said interior region.

28. A plasma reactor system according to claim 27, further including:

a) two or more electrode segment RF power supply systems electronically connected to respective said two or more electrode segments; and

b) a main RF power supply system electronically connected to said upper electrode.

29. A plasma reactor system according to claim 28, wherein said main RF power supply system and said electrode segment RF power supply systems each include a frequency generator, a gain stage, a phase shifter, a match network, and a bandpass filter.

30. A plasma reactor system according to claim 28, further including a gas supply system in pneumatic communication with said interior region, for supplying gas to said interior region.

31. A plasma reactor system according to claim 30, further including a wafer handling system in operative communication with said plasma chamber, for placing and removing substrates onto and from said substrate support member.

32. A plasma reactor system according to claim 31, further including a main control system electronically connected to said cooling system, said vacuum system, said two or more electrode segment RF power supply systems, said main RF power supply system, said gas supply system and said wafer handling system, for controlling said cooling system, said vacuum system, said two or more electrode segment RF power supply systems, said main RF power supply system, said gas supply system and said wafer handling system through electronic signals generated by said main control system.

33. A plasma reactor system comprising:

a) a plasma chamber having a lower wall and chamber sidewalls;

b) a substrate support member having a support surface for supporting a substrate, arranged adjacent said lower wall; and

c) an electrode assembly according to claim 2 or 5, arranged adjacent said substrate support member and within said chamber sidewalls such that said lower surface of said upper electrode and a surface of said substrate are substantially parallel and form, in combination with said chamber sidewalls, an interior region capable of containing a plasma.

34. A plasma reactor system according to claim 33, further including a cooling system in fluid communication with said electrode assembly, for flowing fluid through said electrode assembly.

35. A plasma reactor system according to claim 34, further including a vacuum system in pneumatic communication with said interior region, for regulating the pressure of said interior region.

36. A plasma reactor system according to claim 35, further including:

a) two or more electrode segment RF power supply systems electronically connected to respective said two or more electrode segments; and

b) a main RF power supply system electronically connected to said upper electrode.

37. A plasma reactor system according to claim 36, wherein said two or more electrode segment RF power supply systems and said main RF power supply system each include a frequency generator, a gain stage, a phase shifter, a match network, and a bandpass filter.

38. A plasma reactor system according to claim 36, further including a gas supply system in pneumatic communication with said interior region, for supplying gas to said interior region.

39. A plasma reactor system according to claim 38, further including an actuator controller system in operative communication with said one or more actuators.

40. A plasma reactor according to claim 39, wherein said one or more actuators are electronic actuators electrically connected to said actuator controller system.

41. A plasma reactor system according to claim 40, further including a wafer handling system in operative communication with said plasma chamber for placing and removing substrates onto and from said substrate support member.

42. A plasma reactor system according to claim 41, further including a main control system electronically connected to said cooling system, said vacuum system, said two or more electrode segment RF power supply systems, said main RF power supply system, said gas supply system, said actuator controller system and said wafer handling system, for controlling said cooling system, said vacuum system, said two or more electrode segment RF power supply systems, said main RF power supply system, said gas supply system, said actuator controller system and said wafer handling system through electronic signals generated by said main control system.

43. An electrode assembly according to claim 15, wherein said segmented electrode is an output capacitor of said match network.

44. A system according to claim 25, wherein said electrode assembly is a first modular electrode assembly that is removable and capable of being replaced with a second modular electrode assembly.

45. A system according to claim 33, wherein said electrode assembly is a first modular electrode assembly that is removable and capable of being replaced with a second modular electrode assembly.

46. An electrode assembly according to claim 2, 4 or 5, further including a modular housing enclosing said two or more separated electrode segments and said outer edge, said modular housing having dielectric side walls, and an upper wall, which in combination with said upper surface of said upper electrode define an electrode cavity containing a dielectric cooling fluid which is circulated around said electrode segments, over said upper surface of said upper electrode, and through said controlled gaps.

17. An electrode assembly for providing a controlled RF electric field profile within a region capable of supporting a plasma, comprising:

a) an upper electrode having a lower surface, an upper surface and an outer edge, wherein the region capable of supporting a plasma is adjacent said upper electrode lower surface;

b) a segmented electrode arranged proximate to said upper electrode upper surface, comprising two or more separated electrode segments each having an upper and lower surface, said two or more separated electrode segments being spaced apart from said upper electrode upper surface by corresponding controlled gaps; and

c) a modular housing enclosing said two or more separated electrode segments and said outer edge, said modular housing having dielectric side walls, and an upper wall, which in combination with said upper surface of said upper electrode define an electrode cavity containing a dielectric cooling fluid which is circulated around said electrode segments, over said upper surface of said upper electrode, and through said controlled gaps.

47. An electrode assembly for providing a controlled RF electric field profile within a region capable of supporting a plasma, comprising:

a) an upper electrode having a lower surface, an upper surface and an outer edge, wherein the region capable of supporting a plasma is adjacent said upper electrode lower surface; and

b) a segmented electrode arranged proximate to said upper electrode upper surface, comprising two or more separated electrode segments each having an upper and lower surface, at least lower surfaces of said two or more separated electrode segments being spaced apart from said upper electrode upper surface by corresponding controlled gaps, and

further including first corrugations and first spaces on said lower surfaces of said electrode segments, and second corrugations and second spaces on said upper surface of said upper electrode, wherein said first corrugations are aligned with said second spaces.