Ultraviolet laser apparatus and exposure apparatus using same

• US 20070008609A1
• Filed: 09/13/2006
• Published: 01/11/2007
• Est. Priority Date: 03/11/1998
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Owa, Soichi, Ohtsuki, Tomoko
• Granted Patent: US 7,277,220 B2
• Time in Patent Office: Days
• US Class Current: 359/326
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02F 1/1303 Apparatus specially adapted to the manufacture of LCDs
• CPC Class Codes: G02F 1/35 Non-linear optics
• CPC Class Codes: G02F 1/3501 Constructional details or arrangements of non-linear optical devices, e.g. shape of non-linear crystals
• CPC Class Codes: G02F 1/3503 Structural association of optical elements, e.g. lenses, with the non-linear optical device
• CPC Class Codes: G02F 1/353 Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
• CPC Class Codes: G02F 1/354 Third or higher harmonic generation
• CPC Class Codes: G02F 1/37 for second-harmonic generation G02F1/3532 takes precedence
• CPC Class Codes: G03F 7/70025 by lasers
• CPC Class Codes: G03F 7/70575 Wavelength control, e.g. control of bandwidth, multiple wavelength, selection of wavelength or matching of optical components to wavelength
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/0064 Anti-reflection devices, e.g. optical isolaters absorbing layers for marking or protecting purposes in laser working B23K26/50; magneto-optical non-reciprocal devices G02F1/093, G02F1/0955
• CPC Class Codes: H01S 3/0078 Frequency filtering
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/067 Fibre lasers
• CPC Class Codes: H01S 3/06716 Fibre compositions per se C03C13/04or doping with active elements lasing materials in general H01S3/14
• CPC Class Codes: H01S 3/06729 Peculiar transverse fibre profile
• CPC Class Codes: H01S 3/06745 Tapering of the fibre, core or active region
• CPC Class Codes: H01S 3/06758 : Tandem amplifiers
• CPC Class Codes: H01S 3/06766 : C-band amplifiers, i.e. amplification in the range of about 1530 nm to 1560 nm
• CPC Class Codes: H01S 3/094011 : with bidirectional pumping, i.e. with injection of the pump light from both two ends of the fibre
• CPC Class Codes: H01S 3/09415 : the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/1608 : erbium
• CPC Class Codes: H01S 3/23 : Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
• CPC Class Codes: H01S 3/2383 : Parallel arrangements

Abstract

An ultraviolet laser apparatus according to the present invention comprises a laser generating portion having a single-wavelength oscillating laser for generating laser light having a single wavelength falling within a wavelength range from an infrared band to a visible band, an optical amplifier having a fiber optical amplifier for amplifying the laser light generated by the laser generating portion, and a wavelength converting portion for wavelength-converting the amplified laser light into ultraviolet light by using a non-linear optical crystal, whereby ultraviolet light having a single wavelength is generated. Further, an exposure apparatus according to the present invention serves to transfer a pattern image of a mask onto a substrate and comprises a light source including a laser apparatus for emitting a laser light having a single wavelength, a first fiber optical amplifier for amplifying the laser light, a light dividing device for dividing or branching the amplified laser light into plural lights, and second fiber optical amplifiers for amplifying the plural divided or branched lights, respectively; and a transmission optical system for transmitting the laser light emitted from the light source to the exposure apparatus.

Claims

1. A laser apparatus comprising:

a laser generating portion that generates pulse light having a single wavelength within a range from an infrared band to a visible band;

an optical amplifier optically connected to the laser generating portion, that includes a plurality of fiber optical amplifiers to amplify the pulse light in plural times; and

a wavelength converting portion optically connected to the optical amplifier, that includes cylindrical lenses and a plurality of non-linear optical crystals to wavelength-convert the amplified pulse light into ultraviolet light, the amplified pulse light being incident on one of the plurality of non-linear optical crystals through the cylindrical lenses.

2. An apparatus according to claim 1, wherein

said cylindrical lenses are provided on an optical path between said one non-linear optical crystal and a different one of said plurality of non-linear optical crystals from said one non-linear optical crystal, and said amplified pulse light is incident on said cylindrical lenses through the different non-linear optical crystal.

3. An apparatus according to claim 2, wherein

said amplified pulse light is wavelength-converted in plural times in said wavelength converting portion.

4. An apparatus according to claim 1, wherein

at least a portion of said optical amplifier is exchanged as a unit.

5. An apparatus according to claim 4, wherein

a phase alignment angle of at least one of said plurality of non-linear optical crystals is adjusted.

6. An apparatus according to claim 5, further comprising:

an optical device which suppresses an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion.

7. An apparatus according to claim 6, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m and said ultraviolet light has a wavelength less than 200 nm.

8. An apparatus according to claim 1, wherein

a phase alignment angle of at least one of said plurality of non-linear optical crystals is adjusted.

9. An apparatus according to claim 8, wherein

said at least one non-linear optical crystal of which the phase alignment angle is adjusted includes a non-linear optical crystal provided optically most downstream position among said plurality of non-linear optical crystals.

10. An apparatus according to claim 1, wherein

at least one of said plurality of non-linear optical crystals is used for NCPM (Non-Critical Phase Matching).

11. An apparatus according to claim 1, wherein

a temperature of at least one of said plurality of non-linear optical crystals is controlled.

12. An apparatus according to claim 8, further comprising:

an optical device which suppresses an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion.

13. An apparatus according to claim 12, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

14. An apparatus according to claim 1, further comprising:

an optical device which suppresses an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion.

15. An apparatus according to claim 14, wherein

at least a part of said optical device is provided between said single wavelength oscillating laser and said wavelength converting portion.

16. An apparatus according to claim 15, wherein

said at least a part of said optical device is provided among said plurality of fiber optical amplifiers.

17. An apparatus according to claim 15, wherein

said at least a part of said optical device includes at least one of a narrow band filter and an isolator.

18. An apparatus according to claim 14, wherein

said expansion of the wavelength width caused by non-linear effectiveness of at least one of said plurality of fiber optical amplifiers is suppressed by means of the reduction of a fiber length of the at least one fiber optical amplifier.

19. An apparatus according to claim 18, wherein

said at least one fiber optical amplifier of which the fiber length is reduced includes a fiber optical amplifier provided optically most downstream position among said plurality of fiber optical amplifiers.

20. An apparatus according to claim 14, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

21. An apparatus according to claim 1, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m.

22. An apparatus according to claim 21, wherein

said ultraviolet light has a wavelength less than 200 nm.

23. An apparatus according to claim 22, wherein

said ultraviolet light is 8-times high harmonic wave having a wavelength within a range from 189 nm to 199 nm or 10-times high harmonic wave having a wavelength within a range from 151 nm to 159 nm.

24. An apparatus according to claim 23, wherein

said pulse light has the wavelength within a range from 1.544 μ

m to 1.552 μ

m, and said ultraviolet light is the 8-times high harmonic wave having the wavelength within a range from 193 nm to 194 nm.

25. An apparatus according to claim 23, wherein

said pulse light has the wavelength within a range from 1.57 μ

m to 1.58 μ

m, and said ultraviolet light is the 10-times high harmonic wave having the wavelength within a range from 157 nm to 158 nm.

26. An apparatus according to claim 1, further comprising:

an adjusting device functionally connected to at least one of said laser generating portion and said optical amplifier, which adjusts an emission property of said ultraviolet light.

27. An apparatus according to claim 26, wherein

said emission property includes at least one of intensity, center wavelength, wavelength width and oscillation interval of said ultraviolet light.

28. An apparatus according to claim 26, wherein

said emission property is adjusted based on information obtained by detecting at least one of said ultraviolet light and light of which a wavelength is different from that of said ultraviolet light.

29. An apparatus according to claim 1, wherein

said laser generating portion includes a single-wavelength oscillating laser that pulse-emits light having a first pulse width and a light modulator that generates said pulse light having a second pulse width narrower than the first pulse width with the pulse-emitted light.

30. An apparatus according to claim 1, further comprising:

a shutter device provided on an optical path through which said pulse light passes.

31. An apparatus according to claim 30, wherein

said shutter device includes an electro-optical modulating element or an acousto-optical modulating element.

32. An apparatus according to claim 31, wherein

said shutter device is provided between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion.

33. An apparatus which irradiates ultraviolet light onto an object, comprising:

a laser apparatus according to claim 1, which generates ultraviolet light having a single wavelength; and

an optical system optically connected to the laser apparatus, through which the ultraviolet light passes.

34. An apparatus according to claim 33, wherein

said object includes a substrate on which a pattern is formed.

35. An apparatus according to claim 33, wherein

said object has a pattern detected by the irradiation of said ultraviolet light.

36. An apparatus according to claim 33, wherein

said object includes a wafer or a mask used in a device manufacturing process.

37. An apparatus according to claim 33, wherein

said object has a photosensitive layer exposed with said ultraviolet light.

38. An apparatus which detects a pattern of an object, comprising:

a laser apparatus according to claim 1, which generates ultraviolet light having a single wavelength; and

an optical system optically connected to the laser apparatus, through which the ultraviolet light passes to illuminate the pattern.

39. An apparatus according to claim 38, wherein

said object includes a substrate on which a pattern is formed.

40. An apparatus according to claim 38, wherein

said object includes a wafer or a mask used in a device manufacturing process.

41. A method of irradiating ultraviolet light onto an object, comprising:

generating pulse light having a single wavelength within a range from an infrared band to a visible band, from a laser generating portion;

amplifying the pulse light in plural times by means of an optical amplifier that includes a plurality of fiber optical amplifiers;

wavelength-converting the amplified pulse light into ultraviolet light by means of a wavelength converting portion that includes cylindrical lenses and a plurality of non-linear optical crystals, the amplified pulse light being incident on one of the plurality of non-linear optical crystals through the cylindrical lenses; and

irradiating the ultraviolet light onto the object through an optical system.

42. A method according to claim 41, wherein

said amplified pulse light is incident on said cylindrical lenses through a different one of said plurality of non-linear optical crystals from said one non-linear optical crystal.

43. A method according to claim 42, wherein

said amplified pulse light is wavelength-converted in plural times in said wavelength converting portion.

44. A method according to claim 41, wherein

at least a portion of said optical amplifier is exchanged as a unit.

45. A method according to claim 44, wherein

a phase alignment angle of at least one of said plurality of non-linear optical crystals is adjusted.

46. A method according to claim 45, wherein

an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion is suppressed.

47. A method according to claim 46, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

48. A method according to claim 41, wherein

a phase alignment angle of at least one of said plurality of non-linear optical crystals is adjusted.

49. A method according to claim 48, wherein

said at least one non-linear optical crystal of which the phase alignment angle is adjusted includes a non-linear optical crystal provided optically most downstream position among said plurality of non-linear optical crystals.

50. A method according to claim 41, wherein

at least one of said plurality of non-linear optical crystals is used for NCPM (Non-Critical Phase Matching).

51. A method according to claim 41, wherein

a temperature of at least one of said plurality of non-linear optical crystals is controlled.

52. A method according to claim 48, wherein

an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion is suppressed.

53. A method according to claim 52, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

54. A method according to claim 41, wherein

an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion is suppressed.

55. A method according to claim 54, wherein

said expansion of the wavelength width is suppressed by an optical device of which at least a part is disposed between said single wavelength oscillating laser and said wavelength converting portion.

56. A method according to claim 55, wherein

said at least a part of said optical device is provided among said plurality of fiber optical amplifiers.

57. A method according to claim 55, wherein

said at least a part of said optical device includes at least one of a narrow band filter and an isolator.

58. A method according to claim 54, wherein

said expansion of the wavelength width caused by non-linear effectiveness of at least one of said plurality of fiber optical amplifiers is suppressed by means of the reduction of a fiber length of the at least one fiber optical amplifier.

59. A method according to claim 58, wherein

said at least one fiber optical amplifier of which the fiber length is reduced includes a fiber optical amplifier provided optically most downstream position among said plurality of fiber optical amplifiers.

60. A method according to claim 54, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

61. A method according to claim 41, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m.

62. A method according to claim 61, wherein

said ultraviolet light has a wavelength less than 200 nm.

63. A method according to claim 62, wherein

said ultraviolet light is 8-times high harmonic wave having a wavelength within a range from 189 nm to 199 nm or 10-times high harmonic wave having a wavelength within a range from 151 nm to 159 nm.

64. A method according to claim 41, wherein

an emission property of said ultraviolet light is adjusted by means of at least one of said laser generating portion and said optical amplifier.

65. A method according to claim 64, wherein

said emission property includes at least one of intensity, center wavelength, wavelength width and oscillation interval of said ultraviolet light.

66. A method according to claim 64, wherein

said emission property is adjusted based on information obtained by detecting at least one of said ultraviolet light and light of which a wavelength is different from that of said ultraviolet light.

67. A method according to claim 41, wherein

said object includes a substrate on which a pattern is formed.

68. A method according to claim 41, wherein

said object has a pattern detected by the irradiation of said ultraviolet light.

69. A method according to claim 41, wherein

said object includes a wafer or a mask used in a device manufacturing process.

70. A method according to claim 41, wherein

said object has a photosensitive layer exposed with said ultraviolet light.

71. A method of detecting a pattern of an object, comprising:

generating pulse light having a single wavelength within a range from an infrared band to a visible band, from a laser generating portion;

amplifying the pulse light in plural times by means of an optical amplifier that includes a plurality of fiber optical amplifiers;

wavelength-converting the amplified pulse light into ultraviolet light by means of a wavelength converting portion that includes cylindrical lenses and a plurality of non-linear optical crystals, the amplified pulse light being incident on one of the plurality of non-linear optical crystals through the cylindrical lenses; and

irradiating the ultraviolet light onto the pattern through an optical system.

72. A method according to claim 71, wherein

said amplified pulse light is incident on said cylindrical lenses through a different one of said plurality of non-linear optical crystals from said one non-linear optical crystal.

73. A method according to claim 72, wherein

said amplified pulse light is wavelength-converted in plural times in said wavelength converting portion.

74. A method according to claim 71, wherein

at least a portion of said optical amplifier is exchanged as a unit.

75. A method according to claim 74, wherein

a phase alignment angle of at least one of said plurality of non-linear optical crystals is adjusted.

76. A method according to claim 75, wherein

an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion is suppressed.

77. A method according to claim 76, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

78. A method according to claim 71, wherein

a phase alignment angle of at least one of said plurality of non-linear optical crystals is adjusted.

79. A method according to claim 78, wherein

said at least one non-linear optical crystal of which the phase alignment angle is adjusted includes a non-linear optical crystal provided optically most downstream position among said plurality of non-linear optical crystals.

80. A method according to claim 71, wherein

at least one of said plurality of non-linear optical crystals is used for NCPM (Non-Critical Phase Matching).

81. A method according to claim 71, wherein

a temperature of at least one of said plurality of non-linear optical crystals is controlled.

82. A method according to claim 78, wherein

an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion is suppressed.

83. A method according to claim 82, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

84. A method according to claim 71, wherein

an expansion of a wavelength width of light between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion is suppressed.

85. A method according to claim 84, wherein

said expansion of the wavelength width is suppressed by an optical device of which at least a part is disposed between said single wavelength oscillating laser and said wavelength converting portion.

86. A method according to claim 85, wherein

said at least a part of said optical device is provided among said plurality of fiber optical amplifiers.

87. A method according to claim 85, wherein

said at least a part of said optical device includes at least one of a narrow band filter and an isolator.

88. A method according to claim 84, wherein

said expansion of the wavelength width caused by non-linear effectiveness of at least one of said plurality of fiber optical amplifiers is suppressed by means of the reduction of a fiber length of the at least one fiber optical amplifier.

89. A method according to claim 88, wherein

said at least one fiber optical amplifier of which the fiber length is reduced includes a fiber optical amplifier provided optically most downstream position among said plurality of fiber optical amplifiers.

90. A method according to claim 84, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m, and said ultraviolet light has a wavelength less than 200 nm.

91. A method according to claim 71, wherein

said pulse light has the single wavelength within a range from 1.51 μ

m to 1.59 μ

m.

92. A method according to claim 91, wherein

said ultraviolet light has a wavelength less than 200 nm.

93. A method according to claim 92, wherein

said ultraviolet light is 8-times high harmonic wave having a wavelength within a range from 189 nm to 199 nm or 10-times high harmonic wave having a wavelength within a range from 151 nm to 159 nm.

94. A method according to claim 71, wherein

an emission property of said ultraviolet light is adjusted by means of at least one of said laser generating portion and said optical amplifier.

95. A method according to claim 94, wherein

said emission property includes at least one of intensity, center wavelength, wavelength width and oscillation interval of said ultraviolet light.

96. A method according to claim 94, wherein

said emission property is adjusted based on information obtained by detecting at least one of said ultraviolet light and light of which a wavelength is different from that of said ultraviolet light.

97. A method according to claim 71, wherein

said object includes a substrate on which a pattern is formed.

98. A method according to claim 71, wherein

said object includes a wafer or a mask used in a device manufacturing process.