Method and apparatus for an improved upper electrode plate with deposition shield in a plasma processing system

• US 7,147,749 B2
• Filed: 09/30/2002
• Issued: 12/12/2006
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Nishimoto, Shinya, Nakayama, Hiroyuki, Mitsuhashi, Kouji
• Primary Examiner(s): Hassanzadeh, Parviz
• Assistant Examiner(s): CROWELL, ANNA M
• Application Number:
  US10/259,858
• Publication Number:
  US 20040060661A1
• Time in Patent Office: 1,534 Days
• Field of Search: 118/723.E, 118/723.R, 156/345.43, 156/345.44, 156/345.45, 156/345.46, 156/345.47
• US Class Current: 156/345.43
• CPC Class Codes: C23C 16/4404 Coatings or surface treatment on the inside of the reaction chamber or on parts thereof
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32532 Electrodes
• CPC Class Codes: Y10S 156/916 Differential etching apparatus including chamber cleaning means or shield for preventing deposits

Abstract

The present invention presents an improved upper electrode for a plasma processing system, wherein the design and fabrication of an electrode plate with a deposition shield coupled to the upper electrode advantageously provides gas injection of a process gas with substantially minimal erosion of the upper electrode while providing protection to a chamber interior.

Claims

1. An upper electrode assembly for a plasma processing system, comprising:

an electrode plate comprising a first surface for coupling said upper electrode to an upper assembly, a second surface comprising a plasma surface and a mating surface for mating said electrode plate with said plasma processing system, a peripheral edge, and a plurality of gas injection orifices coupled to said first surface and said second surface;

a deposition shield attached said electrode plate, said deposition shield comprising a cylindrical wall having an inner surface contiguous with said plasma surface, an outer surface contiguous with said mating surface, and a distal end surface, wherein said distal end surface comprises;

a distal end mating surface extending radially inward from said outer surface, and

a protrusion adjacent to said inner surface and protruding from said distal end mating surface, said protrusion having a distal end lip surface thereon; and

a protective barrier provided on exposed surfaces of said upper electrode assembly, said exposed surfaces comprising said plasma surface, said inner surface, and said distal end lip surface.

2. The upper electrode assembly as recited in claim 1, wherein said electrode plate further comprises a plenum cavity formed in said first surface, said plenum cavity having a plenum surface having said plurality of gas injection orifices formed therein such that said plenum cavity receives said processing gas and distributes said processing gas to said plurality of gas injection orifices.

3. The upper electrode assembly as recited in claim 1, wherein said electrode plate further comprises at least one of a first sealing feature and a second sealing feature coupled to said first surface and configured to seal said electrode plate to said upper electrode.

4. The upper electrode assembly as recited in claim 1, wherein said electrode plate further comprises a diagnostics port that couples a diagnostics system to said plasma processing system, and a fourth sealing feature configured to seal said diagnostics port when said upper electrode is coupled to said upper assembly.

5. The upper electrode assembly as recited in claim 1, wherein said protective barrier comprises Al₂O₃.

6. The upper electrode assembly as recited in claim 1, wherein said protective barrier comprises a mixture of Al₂O₃ and Y₂O₃.

7. The upper electrode assembly as recited in claim 1, wherein said protective barrier comprises a compound containing at least one of a group III element and a Lanthanon element.

8. The upper electrode assembly as recited in claim 7, wherein said group III element comprises at least one of Yttrium, Scandium, and Lanthanum.

9. The upper electrode assembly as recited in claim 7, wherein said Lanthanon element comprises at least one of Cerium, Dysprosium, and Europium.

10. The upper electrode assembly as recited in claim 1, wherein said protective barrier comprises at least one of Yttria (Y₂O₃), Sc₂O₃, Sc₂F₃, YF₃, La₂O₃, CeO₂, Eu₂O₃, and DyO₃.

11. The upper electrode assembly as recited in claim 1, wherein said gas injection orifice comprises an entrant region, and an exit region, wherein said exit region comprises an injection surface.

12. The upper electrode assembly as recited in claim 1, further comprising one or more fastening through-holes coupled to said first surface of said electrode plate, extending through said electrode plate and said deposition shield and coupled to a distal end mating surface of said distal end surface, wherein:

said fastening through hole configured to couple said electrode plate and said deposition shield to said plasma processing system, and

each of said one or more fastening through-holes comprises a third sealing feature that seals said one or more fastening through-holes when said upper electrode is coupled to said upper assembly.

13. The upper electrode assembly as recited in claim 1, wherein said protective barrier comprises a minimum thickness and said minimum thickness is constant across at least one of said exposed surfaces.

14. The upper electrode assembly as recited in claim 1, wherein said protective barrier comprises a variable thickness, said variable thickness ranging from 0.5 microns to 500 microns.

15. The upper electrode assembly as recited in claim 1, wherein at least one gas injection orifice has a diameter that is at least 0.1 mm.

16. The upper electrode assembly as recited in claim 1, wherein at least one gas injection orifice has a length that is at least 1.0 mm.

17. The upper electrode assembly as recited in claim 11, wherein said exposed surfaces includes said injection surface of said plurality of gas injection orifices.

18. The upper electrode assembly as recited in claim 4, wherein said exposed surfaces, having said protective barrier provided thereon, comprises said interior surface of said diagnostics port.

19. The upper electrode assembly as recited in claim 1, wherein said deposition shield further comprises an opening in order to access said process space through said deposition shield.

20. The upper electrode assembly as recited in claim 19, wherein said opening comprises:

a first opening surface extending radially inward from said outer surface;

a second opening surface extending radially outward from said inner surface; and

a mating surface coupling said first opening surface to said second opening surface.

21. The upper electrode assembly as recited in claim 20, wherein said mating surface comprises at least one tapped hole and a fastening surface coupled thereto.

22. The upper electrode assembly shield as recited in claim 20, wherein said exposed surfaces, having said protective barrier provided thereon, further comprise said first opening surface of said opening, and said mating surface of said opening in said deposition shield.

23. The upper electrode assembly as recited in claim 21, wherein said exposed surfaces, having said protective barrier provided thereon, further comprise said first opening surface of said opening, and said mating surface excluding said fastening surface of said opening in said deposition shield.

49. The upper electrode assembly as recited in claim 2, wherein said plurality of gas injection orifices each comprise:

an entrant region that opens to said plenum surface; and

an exit region that opens to said second surface, wherein said exit region comprises an injection surface.

50. The upper electrode assembly as recited in claim 49, wherein said entrant region has a larger diameter than said exit region, said plurality of gas injection orifices each further comprising a tapered transition that couples said entrant region to said exit region.

51. The upper electrode assembly as recited in claim 2, wherein said protective barrier is provided on at least a portion of each of said plurality of gas injection orifices.

52. The upper electrode assembly as recited in claim 51, wherein said protective barrier is provided on only a portion of each of said plurality of gas injection orifices.

53. The upper electrode assembly as recited in claim 50, wherein said protective barrier is provided on said exit region, and said protective barrier is not provided on said entrant region.

54. The upper electrode assembly as recited in claim 53, wherein at least a portion of said entrant region is anodized.

55. The upper electrode assembly as recited in claim 4, wherein said diagnostics port comprises:

an entrant cavity opening to said first surface, and

an exit through-hole coupled to said entrant cavity, and opening to said second surface.

56. The upper electrode assembly as recited in claim 55, wherein said protective barrier is provided on at least a portion of said diagnostics port.

57. The upper electrode assembly as recited in claim 56, wherein said protective barrier is provided on only a portion of said diagnostics port.

58. The upper electrode assembly as recited in claim 55, wherein

said entrant cavity comprises a bottom surface adjacent to said exit through hole,

said exit through hole comprises a tapered opening coupling said bottom surface to said exit through hole,

said protective barrier is provided on said bottom surface, said tapered opening and a remaining portion of said exit through hole, and

said protective barrier is not provided on a remaining portion of said entrant cavity.

59. The upper electrode assembly as recited in claim 58, wherein said remaining portion of said entrant cavity is anodized.

60. The upper electrode assembly as recited in claim 21, further comprising a recess recessed from said mating surface, said recess being positioned between said tapped hole and said second opening surface.

61. The upper electrode assembly as recited in claim 60, wherein:

said protective barrier comprises a first protective barrier area provided on a portion of said mating surface extending from said first opening surface, and a second protective barrier area provided on a portion of said recess including a sidewall of said recess adjacent to said tapped hole, and

said fastening surfaces include a first fastening surface extending from said first protective barrier area to said tapped hole, and a second fastening surface extending from said second protective barrier area to said tapped hole.

62. The upper electrode assembly as recited in claim 61, wherein:

said outer surface and said second opening surface are anodized, and

said tapped hole and said first and second fastening surfaces are not anodized and do not have said protective barrier provided thereon.

63. The upper electrode assembly as recited in claim 1, further comprising a recess radially positioned between said distal end mating surface and said protrusion, said recess being recessed from said distal end mating surface.

64. The upper electrode assembly as recited in claim 63, wherein said protective barrier is provided on said end lip surface and said protective barrier is not provided on said recess.

24. An upper electrode assembly for a plasma processing chamber comprising:

a cylindrical element having a first surface, a mating surface, a peripheral edge coupled to said first surface and said mating surface, an outer surface coupled to said mating surface, an inner surface coupled to said outer surface by a distal end surface, and a plasma surface coupled to said inner surface, wherein;

said first surface comprises a coupling surface for coupling said upper electrode to said plasma processing chamber and a plenum cavity formed in said first surface and

said distal end surface comprises a first surface extending radially inward from said outer surface, and a protrusion adjacent to said inner surface and protruding from said first surface, said protrusion having a distal end lip surface thereon, and

said cylindrical element further comprising a plurality of gas injection orifices coupled to said plenum cavity and said plasma surface; and

a protective barrier coupled to exposed surfaces of said upper electrode, said exposed surfaces comprising said plasma surface, said inner surface, and said distal end lip surface.

25. The upper electrode assembly as recited in claim 24, wherein said upper electrode assembly further comprises at least one sealing feature located on said first surface at a position radially outside said plenum cavity and configured to receive a seal.

26. The upper electrode assembly as recited in claim 24, wherein said upper electrode further comprises:

a plurality of fastening through-holes coupled to said first surface, extending through said electrode plate and said deposition shield and coupled to a distal end mating surface of said distal end surface, said plurality of through-holes configured to receive a fastening device, and

a plurality of sealing features, each sealing feature located on said first surface surrounding one of the through-holes, and configured to receive a seal.

27. The upper electrode assembly as recited in claim 24, wherein said upper electrode further comprises a plurality of fastener receptors coupled to said first surface and configured to receive a fastener.

28. The upper electrode assembly as recited in claim 24, wherein each gas injection orifice comprises an entrant region coupled to said plenum cavity, and an exit region, said exit region comprising an injection surface coupled to said plasma surface.

29. The upper electrode assembly as recited in claim 28, wherein said exposed surfaces, having said protective barrier thereon, include each injection surface of said plurality of gas injection orifices.

30. The upper electrode assembly as recited in claim 24, wherein said upper electrode is formed of a metal.

31. The upper electrode assembly as recited in claim 30, wherein said metal comprises aluminum.

32. The upper electrode assembly as recited in claim 24, wherein said protective barrier comprises a compound containing at least one of a group III element and a Lanthanon element.

33. The upper electrode assembly as recited in claim 32, wherein said group III element comprises at least one of Yttrium, Scandium, and Lanthanum.

34. The upper electrode assembly as recited in claim 32, wherein said Lanthanon element comprises at least one of Cerium, Dysprosium, and Europium.

35. The upper electrode assembly as recited in claim 24, wherein said protective barrier comprises at least one of Al₂O₃, Y₂O₃, Sc₂O₃, Sc₂F₃, YF₃, La₂O₃, CeO₂, Eu₂O₃, and DyO₃.

36. The upper electrode assembly as recited in claim 24, wherein said first surface comprises an anodization layer.

37. The upper electrode assembly as recited in claim 24, wherein said plenum cavity comprises an anodization layer.

38. The upper electrode assembly as recited in claim 24, wherein said mating surface comprises a metallic surface.

39. The upper electrode assembly as recited in claim 24, wherein said protective barrier comprises a minimum thickness and said minimum thickness is constant across at least one of said exposed surfaces.

40. The upper electrode assembly as recited in claim 24, wherein said protective barrier comprises a variable thickness, said variable thickness ranging from 0.5 microns to 500 microns.

41. The upper electrode assembly as recited in claim 24, wherein at least one gas injection orifice has a diameter that is at least 0.1 mm.

42. The upper electrode assembly as recited in claim 24, wherein at least one gas injection orifice has a length that is at least 1.0 mm.

43. The upper electrode assembly as recited in claim 24, wherein said upper electrode further comprises:

a diagnostics port having an interior surface coupled to said first surface and said plasma surface; and

a fourth sealing feature located on said first surface, surrounding said diagnostic port, and configured to receive a seal.

44. The upper electrode assembly as recited in claim 43, wherein said exposed surfaces further comprise said interior surface.

45. The upper electrode assembly as recited in claim 24, wherein said upper electrode further comprises an opening coupled between said outer surface and said inner surface.

46. The upper electrode assembly as recited in claim 45, wherein said opening comprises a first opening surface coupled to the inner surface, a second opening surface coupled to the outer surface, and a mating surface coupled to the first opening surface and to the second opening surface.

47. The upper electrode assembly as recited in claim 46, wherein said mating surface comprises at least one tapped hole and a fastening surface coupled thereto.

48. The upper electrode assembly as recited in claim 46, wherein said exposed surfaces further comprise said first opening surface and said mating surface excluding said fastening surface.

77. The upper electrode assembly as recited in claim 35, wherein said protective barrier comprises at least one of Al₂O₃, Y₂O₃, Sc₂O₃, Sc₂F₃, YF₃, La₂O₃, CeO₂, Eu₂O₃, and DyO₃.

65. An upper electrode assembly for a plasma processing system comprising:

an electrode plate comprising a first surface for coupling said upper electrode assembly to an upper assembly, a second surface comprising a plasma surface and a mating surface for mating said electrode plate with said plasma processing system, a peripheral edge, and a plurality of gas injection orifices coupled to said first surface and said second surface;

a deposition shield attached to said electrode plate, said deposition shield comprising a cylindrical wall having an inner surface contiguous with said plasma surface, an outer surface contiguous with said mating surface, a distal end surface, and an opening formed in said cylindrical wall and having an opening surface extending from said inner surface to said outer surface; and

a protective barrier provided on said plasma surface, said inner surface, and only a portion of said opening surface, wherein said opening surface comprises;

a first opening surface extending radially inward from said outer surface,

a second opening surface extending radially outward from said inner surface,

a mating surface coupling said first opening surface to said second opening surface,

at least one tapped hole in said mating surface, and

a fastening surface coupled to said at least one tapped through-hole.

66. The upper electrode assembly shield as recited in claim 65, wherein said protective barrier is provided on said first opening surface of said opening, and said mating surface excluding said fastening surface of said opening in said deposition shield.

67. The upper electrode assembly as recited in claim 65, wherein said electrode plate further comprises a plenum cavity formed in said first surface, said plenum cavity having a plenum surface having said plurality of gas injection orifices formed therein such that said plenum cavity receives said processing gas and distributes said processing gas to said plurality of gas injection orifices.

68. The upper electrode assembly as recited in claim 67, wherein said electrode plate further comprises a diagnostics port radially positioned between said plenum cavity and said peripheral edge, which couples a diagnostics system to said plasma processing system.

69. The upper electrode assembly as recited in claim 68, further comprising one or more fastening through-holes coupled to said first surface of said electrode plate, extending through said electrode plate and said deposition shield and coupled to a distal end mating surface of said distal end surface, wherein:

said fastening through hole is radially positioned between said plenum cavity and said peripheral edge, and

is configured to couple said electrode plate and said deposition shield to said plasma processing system.

70. The upper electrode assembly as recited in claim 69 further comprising one or more fastening receptors positioned radially between said peripheral edge and said plenum cavity.

71. The upper electrode assembly as recited in claim 70 further comprising:

a first annular sealing feature radially positioned between said plenum cavity and said fastening receptors;

a second annular sealing feature radially positioned between said fastening through-hole and said peripheral edge;

a third sealing feature surrounding said fastening through hole; and

a fourth sealing feature surrounding said diagnostics port.

75. The upper electrode assembly as recited in claim 65, wherein said protective barrier consists essentially of Yttria.

76. The upper electrode assembly shield as recited in claim 66, wherein said protective barrier is provided on said first opening surface of said opening, and said mating surface excluding said fastening surface of said opening in said deposition shield.

78. The upper electrode assembly as recited in claim 67, wherein:

said plenum surface includes an anozidation layer provided thereon, and

said first surface other than said plenum surface does not include an anodization layer provided thereon and dos not include said protective barrier provided thereon.

72. An upper electrode assembly for a plasma processing system comprising:

an electrode plate comprising a first surface for coupling said upper electrode assembly to an upper assembly, a second surface comprising a plasma surface and a mating surface for mating said electrode plate with said plasma processing system, a peripheral edge, and a plurality of gas injection orifices coupled to said first surface and said second surface;

a deposition shield attached to said electrode plate, said deposition shield comprising a cylindrical wall having an inner surface contiguous with said plasma surface, an outer surface contiguous with said mating surface, a distal end surface, and an opening formed in said cylindrical wall and having an opening surface extending from said inner surface to said outer surface; and

a protective barrier provided on said plasma surface, said inner surface, and only a portion of said opening surface, wherein said distal end surface comprises;

a distal end mating surface extending radially inward from said outer surface, and

a protrusion adjacent to said inner surface and protruding from said distal end mating surface, said protrusion having a distal end lip surface thereon.

73. The upper electrode assembly as recited in claim 72, further comprising a recess radially positioned between said distal end mating surface and said protrusion, said recess being recessed from said distal end mating surface.

74. The upper electrode assembly as recited in claim 73, wherein said protective barrier is provided on said end lip surface and said protective barrier is not provided on said recess.