Ultraviolet laser apparatus and exposure apparatus using same

• US 7,023,610 B2
• Filed: 02/19/2003
• Issued: 04/04/2006
• Est. Priority Date: 03/11/1998
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Owa, Soichi, Ohtsuki, Tomoko
• Primary Examiner(s): Lee, John D.
• Application Number:
  US10/367,863
• Publication Number:
  US 20030231663A1
• Time in Patent Office: 1,140 Days
• Field of Search: 359326-333, 359/337, 3593411-3415, 372 4- 6, 372/21, 372/22, 372/25, 372/39, 372/68
• US Class Current: 359/328
• 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 having a single-wavelength oscillating laser generating laser light between an infrared band and a visible band, an optical amplifier for amplifying the laser light, and a wavelength converting portion converting the amplified laser light into ultraviolet light using a non-linear optical crystal. An exposure apparatus transfers a pattern image of a mask onto a substrate and includes a light source having a laser apparatus emitting 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 1.51 μ

m to 1.59 μ

m;

an optical amplifier optically connected with 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 with the optical amplifier, that includes a plurality of non-linear optical crystals to wavelength-convert the amplified pulse light into ultraviolet light.

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

a temperature controlling device connected with said wavelength convening portion to control temperature of at least one of said plurality of non-linear optical crystals or combinations thereof.

3. An apparatus according to claim 1, wherein

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

4. An apparatus according to claim 3, wherein

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

5. An apparatus according to claim 3, 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.

6. An apparatus according to claim 3, wherein

said laser generating portion includes a single-wavelength oscillating laser that emits continuous light and a light modulator that converts the continuous light into said pulse light.

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

an adjusting device connected with at least one of said laser generating portion and/or said optical amplifier to adjust an emission property of said ultraviolet light from said wavelength converting portion.

8. An apparatus according to claim 7, wherein

said adjusting device adjusts at least one of intensity, center wavelength, wavelength width and/or oscillation interval of said ultraviolet light as said emission property.

9. An apparatus according to claim 8, wherein

said laser generating portion includes a single-wavelength oscillating laser and/or a light modulator, at least one of which is connected with said adjusting device.

10. An apparatus according to claim 9, wherein

said adjusting device adjusts said emission property by controlling at least one of temperature of said single-wavelength oscillating laser, a control parameter of said single-wavelength oscillating laser, and/or a control parameter of said light modulator.

11. An apparatus according to claim 10, wherein

said adjusting device adjusts the intensity of said ultraviolet light by means of at least one of said single-wavelength oscillating laser, said light modulator and/or said optical amplifier.

12. An apparatus according to claim 11, wherein

said adjusting device detects light of which a wavelength is different from that of said ultraviolet light to operate said adjustment of said emission property based on the detected result.

13. An apparatus according to claim 12, wherein

said adjusting device detects ultraviolet light generated from said wavelength converting portion to operate said adjustment of said emission property based on the detected result.

14. An apparatus according to claim 7, wherein

said plurality of fiber optical amplifiers includes an erbium doped fiber amplifier.

15. An apparatus according to claim 7, wherein

said plurality of fiber optical amplifiers includes a fiber amplifier doped by erbium and ytterbium.

16. An apparatus according to claim 7, wherein

at least one of said plurality of fiber optical amplifiers or combinations thereof comprises one of a quartz fiber, a silicate group fiber and a fluoride group fiber.

17. An apparatus according to claim 7, wherein

at least one of said plurality of fiber optical amplifiers or combinations thereof comprises a ZBLAN fiber.

18. An apparatus according to claim 7, wherein

said plurality of fiber optical amplifiers includes a large mode diameter fiber amplifier.

19. An apparatus according to claim 7, wherein

said laser generating portion includes a single-wavelength oscillating laser that comprises a DFB semiconductor laser or a fiber laser having an oscillating wavelength within said range from 1.51 μ

m to 1.59 μ

m.

20. An apparatus according to claim 7, wherein

said ultraviolet light has a wavelength less than 200 nm.

21. An apparatus according to claim 20, wherein

said wavelength converting portion generates ultraviolet light having 8-times or 10-times high harmonic wave which is obtained from said amplified pulse light.

22. An apparatus according to claim 21, wherein said wavelength converting portion generates the 8-times high harmonic wave having a wavelength within a range from 189 nm to 199 nm.

23. An apparatus according to claim 22, wherein

said laser generating portion generates the pulse light having an oscillating wavelength within a range from 1.544 μ

m to 1.552 μ

m, and said wavelength converting portion generates the 8-times high harmonic wave having the wavelength within a range from 193 nm to 194 nm.

24. An apparatus according to claim 21, wherein

said wavelength converting portion generates the 10-times high harmonic wave having a wavelength within a range from 151 nm to 159 nm.

25. An apparatus according to claim 24, wherein

said laser generating portion generates the pulse light having an oscillating wavelength within a range from 1.57 μ

m to 1.58 μ

m, and said wavelength converting portion generates the 10-times high harmonic wave having the wavelength within a range from 157 nm to 158 nm.

26. An exposure apparatus comprising:

a laser apparatus according to claim 1; and

an illumination system optically connected with the laser apparatus.

27. An apparatus according to claim 26, wherein

said illumination system illuminates a first object having a pattern with ultraviolet light generated from said laser apparatus to expose a second object with the ultraviolet light irradiated on the first object.

28. An apparatus according to claim 27, further comprising:

an adjusting device connected with said laser apparatus to adjust an emission property of said ultraviolet light.

29. An apparatus according to claim 28, wherein

said adjusting device adjusts at least one of intensity, center wavelength, wavelength width and/or oscillation interval of said ultraviolet light as said emission property by means of at least one of said laser generating portion and/or optical amplifier.

30. An apparatus according to claim 29, wherein

said laser generating portion includes a single-wavelength oscillating laser and/or a light modulator, at least one of which is connected with said adjusting device.

31. An apparatus according to claim 30, wherein

said adjusting device adjusts said emission property by controlling at least one of temperature of said single-wavelength oscillating laser, a control parameter of said single-wavelength oscillating laser and/or a control parameter of said light modulator.

32. An apparatus according to claim 31, further comprising:

a projection optical system that projects an image of the illuminated pattern onto said second object, and said adjusting device adjusts at least one of center wavelength and/or wavelength width of said ultraviolet light to control an image characteristics of the projection optical system.

33. An apparatus according to claim 29, wherein

said laser generating portion includes a single-wavelength oscillating laser and a light modulator, and said adjusting device adjusts the intensity of said ultraviolet light by means of at least one of the single-wavelength oscillating laser, the light modulator and/or said optical amplifier.

34. An apparatus according to claim 29, wherein

said adjusting device detects light of which a wavelength is different from that of said ultraviolet light to operate said adjustment of said emission property based on the detected result.

35. An apparatus according to claim 34, wherein

said adjusting device detects ultraviolet light generated from said wavelength converting portion to operate said adjustment of said emission property based on the detected result.

36. An apparatus according to claim 29, wherein

said laser apparatus is constructed so that at least said wavelength converting portion is integrally held with at least a portion of said illumination system.

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

a projection optical system that projects an image of the illuminated pattern onto said second object; and

a mark detecting system optically connected with said illumination system to detect through the projection optical system a mark illuminated with said ultraviolet light.

38. An apparatus according to claim 1, wherein

said wavelength converting portion generates the 8-times high harmonic wave having a wavelength within a range from 189 nm to 199 nm or the 10-times high harmonic wave having a wavelength within a range from 151 nm to 159 nm.

39. An apparatus according to claim 38, wherein

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

40. An apparatus according to claim 38, wherein

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

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

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

42. An apparatus according to claim 41, wherein

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

43. An apparatus according to claim 42, wherein

said wavelength converting portion generates the 8-times high harmonic wave having a wavelength within a range from 189 nm to 199 nm or the 10-times high harmonic wave having a wavelength within a range from 151 nm to 159 nm.

44. An apparatus according to claim 42, wherein

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

45. An apparatus according to claim 42, wherein

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

46. An apparatus used in a device manufacturing process, comprising:

a laser apparatus according to claim 1; and

a main body optically connected with the laser apparatus.

47. An apparatus according to claim 46, wherein

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

48. An apparatus according to claim 46, wherein

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

49. An apparatus according to claim 46, wherein

said wavelength converting portion generates the 8-times high harmonic wave having a wavelength within a range from 189 nm to the 199 nm or 10-times high harmonic wave having a wavelength within a range from 151 nm to 159 nm.

50. An apparatus according to claim 46, further comprising:

a shutter device provided on an optical path through which the pulse light passes, that includes an electro-optical modulating element or an acousto-optical modulating element.

51. An apparatus according to claim 46, wherein

said plurality of non-linear optical crystals include at least one non-linear optical crystal, a phase alignment angle of which is adjusted by temperature control.

52. An apparatus according to claim 46, wherein

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

53. An apparatus according to claim 52, wherein

said optical device includes a narrow band filter and an isolator which are disposed between said single wavelength oscillating laser and said wavelength converting portion.

54. An apparatus according to claim 53, wherein

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

55. An apparatus according to claim 46, wherein

said main body, in order to detect patterns on an object, includes an optical system for illuminating said patterns by ultraviolet light from said laser apparatus.

56. An apparatus according to claim 55, wherein

said object is a wafer on which circuit patterns are formed, separately from said patterns on the object.

57. An apparatus according to claim 46, wherein

said main body includes an illumination portion for illuminating ultraviolet light from said laser apparatus to said object in order to work said object.

58. An apparatus according to claim 46, wherein

said main body includes an exposure portion for exposing a photosensitized object by ultraviolet light from said laser apparatus.

59. An apparatus according to claim 58, wherein

said exposure portion includes an illumination system through which said ultraviolet light passes, and said wavelength converting portion is provided within said main body and is optically connected with said illumination system.

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

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

61. An apparatus according to claim 60, wherein

said plurality of non-linear optical crystals include at least one non-linear optical crystal, a phase alignment angle of which is adjusted by temperature control.

62. An apparatus according to claim 60, wherein

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

63. An apparatus according to claim 60, wherein

said optical device includes at least one of a narrow band filter and an isolator which are disposed between said single wavelength oscillating laser and said wavelength converting portion.

64. An apparatus according to claim 60, wherein

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

65. An apparatus according to claim 64, wherein

a fiber length of said fiber optical amplifier, which is one of said plurality of fiber optical amplifiers and is disposed optically most downstream position among them.

66. An apparatus according to claim 64, wherein

said optical device includes at least one of a narrow band filter and an isolator which are disposed between said single wavelength oscillating laser and said wavelength converting portion.

67. An apparatus according to claim 60, wherein

at least a portion of said optical amplifier is exchangeable as a unit, and further comprising a shutter device disposed between said single wavelength oscillating laser and said wavelength converting portion.

68. An apparatus according to claim 1, wherein

said plurality of non-linear optical crystals include at least one non-linear optical crystal, a phase alignment angle of which is adjusted by temperature control.

69. An apparatus according to claim 68, wherein

temperature of a non-linear optical crystal which generates said ultraviolet light and which is disposed optically most downstream position among them is controlled.

70. An apparatus according to claim 68, wherein

at least a portion of said optical amplifier is exchangeable as a unit, and further comprising a shutter device disposed between a single wavelength oscillating laser of said laser generating portion and said wavelength converting portion.

71. An apparatus according to claim 1, wherein

at least a portion of said optical amlifier can be exchanged as a unit.

72. An apparatus according to claim 71, further comprising:

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

73. An apparatus according to claim 71, further comprising:

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

74. An apparatus according to claim 71, wherein

said plurality of non-linear optical crystals include at least one non-linear optical crystal, a phase alignment angle of which is adjusted by temperature control.

75. An apparatus according to claim 1, wherein

said laser generating portion includes a single wavelength oscillating laser and further comprising a shutter device disposed between said single wavelength oscillating laser and said wavelength converting portion.

76. An apparatus according to claim 75, wherein

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

77. An apparatus according to claim 75, further comprising:

an optical device which suppresses an expansion of the wavelength width of light between said single wavelength oscillating lasaer and said wavelength converting portion.

78. An apparatus according to claim 75, wherein

plurality of non-linear optical crystals include at least one non-linear optical crystal, a phase alignment angle of which is adjusted by temperature control.

79. An apparatus according to claim 1, wherein

said laser generating portion includes a single wavelength oscillating laser which oscillates a continuous light and a light modulator which converts said continuous light to said pulse light, and further comprising a shutter device disposed between said single wavelength oscillating laser and said wavelength converting portion.

80. An apparatus according to claim 79, wherein

said laser apparatus includes an optical device which suppresses an expansion of the wavelength width of light between said single wavelength oscillating laser and said wavelength converting portion.

81. An apparatus according to claim 79, wherein

said plurality of non-linear optical crystals include at least one non-linear optical crystal, a phase alignment angle of which is adjusted by temperature control.

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

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

an optical system optically connected to the ultraviolet laser apparatus to illuminate the object with the generated ultraviolet light.

83. An apparatus according to claim 82, wherein

at least a portion of the laser apparatus can be replaced as a unit.

84. An apparatus according to claim 83, wherein

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

85. An apparatus according to claim 82, wherein

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

86. An apparatus according to claim 82, wherein

said object has a pattern which is detected by an illumination of the ultraviolet light.

87. A exposure method of exposing an object with an illumination light, comprising:

generating pulse light having a single wavelength within a range from 1.51 μ

m to 1.59 μ

m 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 a plurality of non-linear optical crystals; and

irradiating the ultraviolet light as the illumination light on a pattern that is transferred onto the object.

88. A method according to claim 87, further comprising:

adjusting an emission property of said ultraviolet light by means of at least one of said laser generating portion and/or said optical amplifier.

89. A method according to claim 88, wherein at least one of intensity, center wavelength, wavelength width and/or oscillation interval of said ultraviolet light is adjusted as said emission property.