PLASMA PROCESSING APPARATUS

• US 20140262034A1
• Filed: 10/03/2012
• Published: 09/18/2014
• Est. Priority Date: 10/07/2011
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Ishibashi, Kiyotaka, Morita, Osamu
• Granted Patent: US 9,767,993 B2
• Time in Patent Office: Days
• US Class Current: 156/345.29
• CPC Class Codes: C23C 16/45563 Gas nozzles
• CPC Class Codes: C23C 16/511 using microwave discharges
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32201 Generating means
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32495 Means for protecting the vessel against plasma
• CPC Class Codes: H05H 1/463 using antennas or applicators

Abstract

This microwave plasma processing apparatus has, as a gas introduction mechanism for introducing a working gas inside a chamber (10), electrical discharge prevention members (96(1) to 96(8)), each of which is provided to a plurality of dielectric window gas passages (94(1) to (94(8)) through which a dielectric window (54) passes. Each electrical discharge prevention member (96(n)), a portion (114) of which protrudes only a height h, which is greater than or equal to a predetermined distance H, upward from the rear surface of a dielectric window (52) on the inlet side, passes through an opening (54a) of a slot plate (54), and inserts into a branched gas supply path (92(n)) of a gas branch part (90). The gas branch part (90), spring coils (116) and the slot plate (54), which surround the protruding portion (114) of each electrical discharge prevention member (96(n)), constitute an enclosing conductor (118).

Claims

1. (canceled)

2. A plasma processing apparatus comprising:

a processing container configured to be evacuated to a vacuum and provided with a dielectric window;

a substrate holding unit configured to hold a substrate to be processed within the processing container;

a dielectric window gas flow path that penetrates the dielectric window;

a processing gas supply unit including an external gas supply path which is connected with the dielectric window gas flow path on a rear side or outside of the dielectric window when viewed from a plasma generation space within the processing container, the processing gas supply unit being configured to supply at least a part of a required processing gas into the processing container through the external gas supply path and the dielectric window gas flow path;

an electromagnetic wave supply unit configured to supply electromagnetic waves into the processing container through the dielectric window;

an electric discharge prevention member integrally formed in or bonded to the dielectric window, the electric discharge prevention member having an inlet connected to an outlet of the external gas supply path and forming a portion or whole of the dielectric window gas flow path; and

a surrounding conductor configured to surround the electric discharge prevention member at least in the vicinity of the inlet of the electric discharge prevention member,

wherein the surrounding conductor surrounds the electric discharge prevention member over an extent which is equal to or longer than a predetermined distance H from the inlet toward an outlet of the electric discharge prevention member.

3. The plasma processing apparatus of claim 2, wherein, assuming that a wavelength the electromagnetic waves is λ

_d when the electromagnetic waves are propagated within the electric discharge prevention member, H≧

0.05λ

_d.

4. The plasma processing apparatus of claim 3, wherein H≧

0.2λ

_d.

5. The plasma processing apparatus of claim 2, wherein, assuming that an inner diameter of the surrounding conductor or a length of a major axis of a maximum inscribed ellipse of the surrounding conductor is D, H≧

0.13D.

6. The plasma processing apparatus of claim 5, wherein H≧

0.5D.

7. The plasma processing apparatus of claim 2, wherein, assuming that the wavelength of the electromagnetic waves is λ

_d when the electromagnetic waves are propagated within the electric discharge prevention member and an inner diameter of the surrounding conductor or a length of a major axis of a maximum inscribed ellipse of the surrounding conductor is D, D≦

0.6λ

_d.

8. The plasma processing apparatus of claim 2, wherein a plurality of dielectric window gas flow paths are provided in the dielectric window in parallel to each other.

9. The plasma processing apparatus of claim 8, wherein, assuming that a distance between a center of the dielectric window and each of the dielectric window gas flow paths is R and the wavelength of the electromagnetic waves is λ

_g when the electromagnetic waves are propagated within the dielectric window, λ

_g/4<

R<

5λ

_g/8.

10. The plasma processing apparatus of claim 9, wherein no dielectric window gas flow path is provided within λ

_g/4 from the center of the dielectric window.

11. The plasma processing apparatus of claim 9, wherein the dielectric window has a rotational symmetry property.

12. The plasma processing apparatus of claim 8, wherein the plurality of dielectric window gas flow paths are arranged on a circumference of a predetermined distance from the center of the dielectric window at equidistant intervals.

13. The plasma processing apparatus of claim 2, wherein the electric discharge prevention member includes a porous dielectric material.

14. The plasma processing apparatus of claim 2, wherein the electric discharge prevention member includes a dielectric material which is formed with a plurality of extra fine through holes.

15. The plasma processing apparatus of claim 2, wherein the electric discharge prevention member includes a dielectric material which is formed with a plurality of longitudinal grooves extending in an axial direction on an outer circumferential surface thereof.

16. The plasma processing apparatus of claim 2, wherein the electric discharge prevention member includes a cylinder portion which is made of a dielectric material and integrally formed in or bonded to the dielectric window.

17. The plasma processing apparatus of claim 2, wherein the electric discharge prevention member protrudes on the rear side of the dielectric window and the protruding portion is surrounded by the surrounding conductor.

18. The plasma processing apparatus of claim 2, wherein at least a portion of the external gas supply path in the vicinity of the outlet is made of a conductor and integrally extending from or connected with the surrounding conductor.

19. The plasma processing apparatus of claim 2, wherein the surrounding conductor is segmented into a plurality of conductor members which are connected with each other along an axial direction.

20. The plasma processing apparatus of claim 2, wherein an electromagnetic field absorption member is provided between a side surface of the electric discharge prevention member and the surrounding conductor.

21. The plasma processing apparatus of claim 2, wherein an endless seal member is provided between a side surface of the electric discharge prevention member and the surrounding conductor.

22. The plasma processing apparatus of claim 21, wherein a recess shielded from an atmospheric space by the seal member is formed between the side surface of the electric discharge prevention member and the surrounding conductor, and

the surrounding conductor surrounds the side surface of the electric discharge prevention member over an extent which is equal to or longer than the predetermined distance H, from the deepest position of the recess.

23. The plasma processing apparatus of claim 2, wherein an endless seal member is provided between an end surface of the inlet of the electric discharge prevention member and the outlet of the external gas supply path.

24. The plasma processing apparatus of claim 2, wherein an endless seal member is provided between the dielectric window and the outlet of the external gas supply path.

25. The plasma processing apparatus of claim 23, wherein a gap formed inside the seal member in the vicinity of the inlet of the electric discharge prevention member is larger than a gap formed outside the seal member.

26. The plasma processing apparatus of claim 25, wherein the gap outside the seal member is 0.2 mm or less and the gap inside the seal member is 0.3 mm or more.

27. The plasma processing apparatus of claim 26, wherein the gap inside the seal member is 0.5 mm to 1.0 mm.

28. The plasma processing apparatus of claim 2, wherein the electromagnetic wave supply unit includes an antenna provided above the dielectric window so as to supply the electromagnetic waves into the processing container.

29. The plasma processing apparatus of claim 28, wherein the antenna is a flat plate-type slot antenna.

30. The plasma processing apparatus of claim 29, wherein the flat plate-type slot antenna has a rotational symmetry property.

31. The plasma processing apparatus of claim 29, wherein a slot plate in the flat plate-type slot antenna forms a part of the surrounding conductor.

32. The plasma processing apparatus of claim 29, wherein the electromagnetic wave supply unit includes:

a microwave generator configured to generate microwaves as the electromagnetic waves, and

a microwave transmission line configured to propagate the microwaves generated from the microwave generator to the flat plate-type slot antenna.

33. The plasma processing apparatus of claim 28, wherein the antenna is a coil type antenna.

34. The plasma processing apparatus of claim 33, wherein the electromagnetic wave supply unit includes:

a high frequency power source configured to generate high frequency waves as the electromagnetic waves,

a high frequency wave transmission unit configured to transmit the high frequency waves from the high frequency power source to the antenna, and

a matching unit configured to match a load impedance of the antenna side to an impedance of the high frequency power source side.

35. The plasma processing apparatus of claim 2, wherein the outlet of the electric discharge prevention member extends to an outlet of the dielectric window gas flow path which faces the plasma generation space within the processing container so as to form a gas jet port.

36. A plasma processing apparatus comprising:

a processing container configured to be evacuated to a vacuum and provided with a dielectric window;

a substrate holding unit configured to hold a substrate to be processed within the processing container;

a dielectric window gas flow path that penetrates the dielectric window;

a processing gas supply unit including an external gas supply path which is connected with the dielectric window gas flow path at the outside of the dielectric window when viewed from a plasma generation space within the processing container, the processing gas supply unit being configured to supply at least a part of a required processing gas into the processing container through the external gas supply path and the dielectric window gas flow path; and

an electromagnetic wave supply unit configured to supply electromagnetic waves for gas-discharge into the processing container through the dielectric window,

wherein, assuming that a distance between a center of the dielectric window and the dielectric window gas flow path is R and the wavelength of the electromagnetic waves is λ

_g when the electromagnetic waves are propagated within the dielectric window, λ

_g/4<

R<

5λ

_g/8.

37. The plasma processing apparatus of claim 36, wherein no dielectric window gas flow path is provided within λ

_g/4 from the center of the dielectric window.

38. The plasma processing apparatus of claim 36, wherein a plurality of dielectric window gas flow paths are provided in the dielectric window in parallel to each other.

39. The plasma processing apparatus of claim 38, wherein the plurality of dielectric window gas flow paths are arranged on a circumference of a predetermined distance from the center of the dielectric window at equidistant intervals.

40. The plasma processing apparatus of claim 36, wherein the dielectric window gas flow path extends in an annular shape.

41. The plasma processing apparatus of claim 40, wherein an opening is formed in a central portion of the dielectric window, a nozzle piece of a dielectric material is fitted in the opening, and the dielectric window gas flow path is formed between the nozzle piece and the opening.

42. The plasma processing apparatus of claim 41, wherein the opening of the dielectric window has first and second opening portions which are coaxial to each other and have first and second diameters, respectively,

the nozzle piece includes a first columnar portion fitted in the first opening portion leaving a first clearance, a second columnar portion fitted in the second opening portion leaving a second clearance, an annular flange surface extending in a radial direction between the first columnar portion and the second columnar portion and coming in close contact with an annular bottom surface or an annular ceiling surface between the first and second opening portions, and a plurality of grooves formed radially on the flange surface, and

the first clearance, the grooves and the second clearance communicate with each other to form the dielectric window gas flow path in a state where the nozzle piece is fitted in the opening of the dielectric window.

43. The plasma processing apparatus of claim 41, wherein the opening of the dielectric window has a diameter which changes in a taper shape in the thickness direction of the dielectric window,

the nozzle piece has a tapered body portion which is in close contact with the opening of the dielectric window and a plurality of grooves formed on an outer circumferential surface of the body portion to extend vertically or obliquely from an upper end to a lower end, and

the grooves form the dielectric window gas flow path in a state where the nozzle piece is fitted in the opening of the dielectric window.

44. The plasma processing apparatus of claim 36, wherein a through hole is formed in the dielectric window,

a nozzle piece of a dielectric material is fitted in the through hole,

a plurality of longitudinal grooves, which extend in an axial direction from one end to the other end of the nozzle piece, are formed on an outer circumferential surface of the nozzle piece in parallel to each other, and

the dielectric window gas flow path is formed by the plurality of longitudinal grooves.

45. The plasma processing apparatus of claim 36, wherein the dielectric window has a rotational symmetry property.

46. The plasma processing apparatus of claim 36, wherein an endless seal member is provided between the dielectric window and an outlet of the external gas supply path.

47. The plasma processing apparatus of claim 46, wherein a gap formed inside the seal member in a vicinity of an inlet of the dielectric window gas flow path is larger than a gap outside the seal member.

48. The plasma processing apparatus of claim 47, wherein the gap formed outside the seal member is 0.2 mm or less and the gap formed inside the seal member is 0.3 mm or more.

49. The plasma processing apparatus of claim 48, wherein the gap formed inside the seal member is 0.5 mm to 1.0 mm.

50. The plasma processing apparatus of claim 36, wherein a first recess is formed in the dielectric window at a position radially inside of the dielectric window gas flow path, and

an electrically grounded protruding conductor is fitted in the first recess.

51. The plasma processing apparatus of claim 36, wherein a second recess is formed in the dielectric window at a position radially outside the dielectric window gas flow path, and

an electrically grounded surrounding conductor is fitted in the second recess.

52. The plasma processing apparatus of claim 36, further comprising:

an electric discharge prevention member integrally formed in or bonded to the dielectric window, the electric discharge prevention member having an inlet connected to an outlet of the external gas supply path and forming a part or whole of the dielectric window gas flow path.

53. The plasma processing apparatus of claim 36, wherein the electromagnetic wave supply unit includes an antenna provided above the dielectric window so as to supply the electromagnetic waves into the processing container.

54. The plasma processing apparatus of claim 53, wherein the antenna is a flat plate-type slot antenna.

55. The plasma processing apparatus of claim 54, wherein the flat plate-type slot antenna has a rotational symmetry property.

56. The plasma processing apparatus of claim 54, wherein a slot plate in the flat plate-type slot antenna forms a part of a surrounding conductor.

57. The plasma processing apparatus of claim 54, wherein the electromagnetic wave supply unit includes:

a microwave generator configured to generate microwaves as the electromagnetic waves, and

a microwave transmission line configured to propagate the microwaves generated from the microwave generator to the flat plate-type slot antenna.

58. The plasma processing apparatus of claim 53, wherein the antenna is a coil type antenna.

59. The plasma processing apparatus of claim 58, wherein the electromagnetic wave supply unit includes:

a high frequency power source configured to generate high frequency waves as the electromagnetic waves,

a high frequency wave transmission unit configured to transmit the high frequency waves from the high frequency power source to the antenna, and

a matching unit configured to match a load impedance of the antenna side to an impedance of the high frequency power source side.

60. The plasma processing apparatus of claim 52, wherein the outlet of the electric discharge prevention member extends to an outlet of the dielectric window gas flow path which faces the plasma generation space within the processing container so as to form a gas jet port.

61. A plasma processing apparatus comprising:

a processing container configured to be evacuated to a vacuum and provided with a dielectric window;

a substrate holding unit configured hold a substrate to be processed within the processing container;

a dielectric window gas flow path that penetrates the dielectric window;

a processing gas supply device including a gas nozzle provided in the dielectric window, and an external gas supply path which is connected with the dielectric window gas flow path on a rear side or outside of the dielectric window when viewed from a plasma generation space within the processing container, the processing gas supply device being configured to supply at least a part of a required processing gas into the processing container through the external gas supply path and the dielectric window gas flow path; and

an electromagnetic wave supply unit configured to supply electromagnetic waves into the processing container through the dielectric window,

wherein the gas nozzle includes a through hole formed in the dielectric window, and a nozzle piece made of a dielectric material fitted in the through hole, and

a plurality of longitudinal grooves, which extend in an axial direction from one end to the other end of the nozzle piece, are formed on an outer circumferential surface of the nozzle piece in parallel to each other.

62. The plasma processing apparatus of claim 61, wherein the ratio of depth and width of each of the longitudinal grooves is 2 or more.

63. The plasma processing apparatus of claim 61, wherein the width of each of the longitudinal grooves is in a rage of 0.05 mm to 0.2 mm.

64. The plasma processing apparatus of claim 63, wherein the depth of each of the longitudinal grooves is in a range of 1 mm to 2 mm.

65. The plasma processing apparatus of claim 61, wherein each of the longitudinal grooves has a rectangular shape in cross section, a long side of the rectangular shape corresponding to the depth of each of the longitudinal grooves and a short side of the rectangular shape corresponding to the width of each of the longitudinal grooves.

66. The plasma processing apparatus of claim 61, wherein the through hole and the nozzle piece have diameters which changes in a same taper angle θ

in a thickness direction of the dielectric window, respectively.

67. The plasma processing apparatus of claim 66, wherein the taper angle θ

is in a range of 0.001≦

tan θ

≦

0.2.

68. The plasma processing apparatus of claim 61, wherein the diameters of the through hole and the nozzle piece change stepwise in a midway thereof in a thickness direction of the dielectric window.

69. The plasma processing apparatus of claim 68, wherein the outer circumferential surface of the nozzle piece is in contact with an inner wall of the through hole from one end to a predetermined middle point in the thickness direction of the dielectric window, and is spaced apart from the inner wall of the through hole from the middle point to the other end, leaving a gap therebetween.

70. The plasma processing apparatus of claim 61, further comprising an adhesive layer between the outer circumferential surface of the nozzle piece and an inner wall of the through hole.

71. The plasma processing apparatus of claim 70, wherein the adhesive layer has a thickness in a range of 0.1 μ

m to 2 μ

m.

72. The plasma processing apparatus of claim 70, wherein the adhesive layer is substantially a compact body of which the porosity is 10% or less.

73. The plasma processing apparatus of claim 70, wherein the adhesive layer is made of or includes a sintered body of a polymer.

74. The plasma processing apparatus of claim 70, wherein the adhesive layer includes a dielectric material which is the same as that of the dielectric window or the nozzle piece.

75. The plasma processing apparatus of claim 70, wherein the adhesive layer is made of or includes a dielectric material which is the same as that of the dielectric window or the nozzle piece.

76. The plasma processing apparatus of claim 70, wherein the material of the adhesive layer has a thermal expansion coefficient which has a relative difference in a range of 5 ppm with reference to thermal expansion coefficients of the dielectric window and the gas nozzle.

77. The plasma processing apparatus of claim 70, wherein the outer circumferential surface of the nozzle piece has a surface roughness in a range of 0.1 μ

m≦

Ra≦

3.2 μ

m wherein Ra is an arithmetic mean roughness.

78. The plasma processing apparatus of claim 70, wherein the inner wall of the through hole has a surface roughness in a range of 0.1 μ

m≦

Ra≦

3.2 μ

m wherein Ra is an arithmetic mean roughness.

79. The plasma processing apparatus of claim 61, wherein, assuming that a distance between a center of the dielectric window and the longitudinal grooves of the gas nozzle is R and the wavelength of the electromagnetic waves is λ

_g when the electromagnetic waves are propagated within the dielectric window, λ

_g/4<

R<

5λ

_g/8.

80. The plasma processing apparatus of claim 79, wherein no dielectric window gas flow path is provided within λ

_g/4 from the center of the dielectric window.

81. The plasma processing apparatus of claim 61, wherein an endless seal member is provided between the dielectric window and an outlet of the external gas supply path.

82. The plasma processing apparatus of claim 81, wherein a gap formed inside the seal member in the vicinity of the inlet of the gas nozzle is larger than a gap formed outside the seal member.

83. The plasma processing apparatus of claim 82, wherein the gap formed outside the seal member is 0.2 mm or less and the gap formed inside the seal member is 0.3 mm or more.

84. The plasma processing apparatus of claim 83, wherein the gap formed inside the seal member is 0.5 mm to 1.0 mm.

85. The plasma processing apparatus of claim 61, further comprising a surrounding conductor configured to surround the gas nozzle at least in the vicinity of an inlet of the gas nozzle.

86-90. -90. (canceled)