Method and apparatus for generating high output power gas discharge based source of extreme ultraviolet radiation and/or soft x-rays

• US 20020168049A1
• Filed: 03/27/2002
• Published: 11/14/2002
• Est. Priority Date: 04/03/2001
• Status: Active Grant

• Current Assignee: Ushio Denki Kabushiki Kaisha
• Original Assignee: Lambda Physik AG (Coherent Corp.)
• Inventors: Schriever, Guido, Rebhan, Ulrich
• Granted Patent: US 6,804,327 B2
• Time in Patent Office: Days
• US Class Current: 378/119
• CPC Class Codes: B03C 3/383 using radiation
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G03F 7/70033 by plasma extreme ultraviolet [EUV] sources
• CPC Class Codes: G03F 7/70175 Lamphouse reflector arrangements or collector mirrors, i.e. collecting light from solid angle upstream of the light source
• CPC Class Codes: G03F 7/70916 Pollution mitigation, i.e. mitigating effect of contamination or debris, e.g. foil traps
• CPC Class Codes: H05G 2/003 being produced from a liquid or gas

Abstract

An EUV photon source includes a plasma chamber filled with a gas mixture, multiple electrodes within the plasma chamber defining a plasma region and a central axis, a power supply circuit connected to the electrodes for delivering a main pulse to the electrodes for energizing the plasma around the central axis to produce an EUV beam output along the central axis, and a preionizer for ionizing the gas mixture in preparing to form a dense plasma around the central axis upon application of the main pulse from the power supply circuit to the electrodes. The EUV source preferably includes an ionizing unit and precipitator for collecting contaminant particulates from the output beam path. A set of baffles may be disposed along the beam path outside of the pinch region to diffuse gaseous and contaminant particulate flow emanating from the pinch region and to absorb or reflect acoustic waves emanating from the pinch region away from the pinch region. A clipping aperture, preferably formed of ceramic and/or Al₂O₃, for at least partially defining an acceptance angle of the EUV beam. The power supply circuit may generates the main pulse and a relatively low energy prepulse for homogenizing the preionized plasma prior to the main pulse. A multi-layer EUV mirror is preferably disposed opposite a beam output side of the pinch region for reflecting radiation along the central axis for output along the beam path of the EUV beam. The EUV mirror preferably has a curved contour for substantially collimating or focusing the reflected radiation. In particular, the EUV mirror may preferably have a hyperbolic contour.

Claims

1. An EUV photon source, comprising:

a plasma chamber filled with a gas mixture;

multiple electrodes within the plasma chamber defining a plasma region and a central axis;

a power supply circuit connected to the electrodes for delivering a main pulse to the electrodes for energizing the plasma around the central axis to produce an EUV beam output;

a preionizer for ionizing the gas mixture in preparing to form a dense plasma around the central axis upon application of the main pulse from the power supply circuit to the electrodes;

an ionization unit positioned along a beam path of the EUV beam outside of the plasma region for ionizing contaminant particulates along the beam path; and

an electrostatic particle filter for collecting the ionized particulates.

2. The EUV source of claim 1, wherein said ionizing unit generates a corona discharge.

3. The EUV source of claim 1, further comprising one or more baffles along the beam path outside of the pinch region.

4. The EUV source of claim 3, the one or more baffles for diffusing gaseous and contaminant particulate flow emanating from the pinch region.

5. The EUV source of claim 4, the one or more baffles further for absorbing or reflecting acoustic waves emanating from the pinch region away from the pinch region.

6. The EUV source of claim 3, further comprising a clipping aperture along the beam path outside of the pinch region for at least partially defining an acceptance angle of the EUV beam.

7. The EUV source of claim 6, wherein said aperture comprises ceramic.

8. The EUV source of claim 6, wherein said aperture comprises Al₂O₃.

9. The EUV source of claim 6, wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

10. The EUV source of claim 9, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

11. The EUV source of claim 10, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

12. The EUV source of claim 10, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

13. The EUV source of claim 6, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

14. The EUV source of claim 13, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

15. The EUV source of claim 13, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

16. The EUV source of claim 3, wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

17. The EUV source of claim 16, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

18. The EUV source of claim 17, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

19. The EUV source of claim 17, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

20. The EUV source of claim 3, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

21. The EUV source of claim 20, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

22. The EUV source of claim 20, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

23. The EUV source of claim 1, further comprising a clipping aperture along the beam path outside of the pinch region for at least partially defining an acceptance angle of the EUV beam.

24. The EUV source of claim 23, wherein said aperture comprises ceramic.

25. The EUV source of claim 23, wherein said aperture comprises Al₂O₃.

26. The EUV source of claim 23, wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

27. The EUV source of claim 26, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

28. The EUV source of claim 27, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

29. The EUV source of claim 27, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

30. The EUV source of claim 23, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

31. The EUV source of claim 30, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

32. The EUV source of claim 30, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

33. The EUV source of claim 1, wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

34. The EUV source of claim 33, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

35. The EUV source of claim 34, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

36. The EUV source of claim 34, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

37. The EUV source of claim 1, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

38. The EUV source of claim 37, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

39. The EUV source of claim 37, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

40. An EUV photon source, comprising:

a plasma chamber filled with a gas mixture;

multiple electrodes within the plasma chamber defining a plasma region and a central axis;

a power supply circuit connected to the electrodes for delivering a main pulse to the electrodes for energizing the plasma around the central axis to produce an EUV beam output;

a preionizer for ionizing the gas mixture in preparing to form a dense plasma around the central axis upon application of the main pulse from the power supply circuit to the electrodes; and

one or more baffles along a beam path outside of the pinch region.

41. The EUV source of claim 40, the one or more baffles for diffusing gaseous and contaminant particulate flow emanating from the pinch region.

42. The EUV source of claim 41, the one or more baffles further for absorbing or reflecting acoustic waves emanating from the pinch region away from the pinch region.

43. The EUV source of claim 40, further comprising a clipping aperture along the beam path outside of the pinch region for at least partially defining an acceptance angle of the EUV beam.

44. The EUV source of claim 43, wherein said aperture comprises ceramic.

45. The EUV source of claim 43, wherein said aperture comprises Al₂O₃.

46. The EUV source of claim 43, wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

47. The EUV source of claim 46, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

48. The EUV source of claim 47, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

49. The EUV source of claim 47, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

50. The EUV source of claim 43, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

51. The EUV source of claim 50, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

52. The EUV source of claim 50, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

53. The EUV source of claim 40, wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

54. The EUV source of claim 53, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

55. The EUV source of claim 54, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

56. The EUV source of claim 54, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

57. The EUV source of claim 40, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

58. The EUV source of claim 57, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

59. The EUV source of claim 57, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

60. An EUV photon source, comprising:

a plasma chamber filled with a gas mixture;

multiple electrodes within the plasma chamber defining a plasma region and a central axis;

a power supply circuit connected to the electrodes for delivering a main pulse to the electrodes for energizing the plasma around the central axis to produce an EUV beam output;

a preionizer for ionizing the gas mixture in preparing to form a dense plasma around the central axis upon application of the main pulse from the power supply circuit to the electrodes; and

a clipping aperture along a beam path outside of the pinch region for at least partially defining an acceptance angle of the EUV beam.

61. The EUV source of claim 60, wherein said aperture comprises ceramic.

62. The EUV source of claim 60, wherein said aperture comprises Al₂O₃.

63. The EUV source of claim 60, wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

64. The EUV source of claim 63, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

65. The EUV source of claim 64, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

66. The EUV source of claim 64, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

67. The EUV source of claim 60, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along the beam path of the EUV beam.

68. The EUV source of claim 67, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

69. The EUV source of claim 67, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

70. An EUV photon source, comprising:

a plasma chamber filled with a gas mixture;

multiple electrodes within the plasma chamber defining a plasma region and a central axis;

a power supply circuit connected to the electrodes for delivering a main pulse to the electrodes for energizing the plasma around the central axis to produce an EUV beam output;

a preionizer for ionizing the gas mixture in preparing to form a dense plasma around the central axis upon application of the main pulse from the power supply circuit to the electrodes, and

wherein said power supply circuit generates the main pulse and a relatively low energy prepulse before said main pulse for homogenizing the preionized plasma prior to the main pulse.

71. The EUV source of claim 70, further comprising a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along a beam path of the EUV beam.

72. The EUV source of claim 71, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

73. The EUV source of claim 71, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

74. An EUV photon source, comprising:

a plasma chamber filled with a gas mixture;

multiple electrodes within the plasma chamber defining a plasma region and a central axis;

a power supply circuit connected to the electrodes for delivering a main pulse to the electrodes for energizing the plasma around the central axis to produce an EUV beam output along the central axis;

a preionizer for ionizing the gas mixture in preparing to form a dense plasma around the central axis upon application of the main pulse from the power supply circuit to the electrodes; and

a multi-layer EUV mirror disposed opposite a beam output side of the pinch region for reflecting radiation in a direction of the beam output side for output along a beam path of the EUV beam.

75. The EUV source of claim 74, wherein the EUV mirror has a curved contour for substantially collimating the reflected radiation.

76. The EUV source of claim 74, wherein the EUV mirror has a curved contour for substantially focusing the reflected radiation.

77. The EUV source of claim 74, wherein the EUV mirror has a hyperbolic contour.

78. The EUV source of claim 74, wherein the electrodes are configured such that the EUV source is of Z-pinch type.

79. The EUV source of claim 74, wherein the electrodes are configured such that the EUV source is of HCT-pinch type.

80. The EUV source of claim 74, wherein the electrodes are configured such that the EUV source is of capillary discharge type.

81. The EUV source of claim 74, wherein the electrodes are configured such that the EUV source is of plasma focus type.