Exposure device with laser device

• US 6,947,123 B1
• Filed: 09/08/2000
• Issued: 09/20/2005
• Est. Priority Date: 09/10/1999
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Ohtsuki, Tomoko
• Primary Examiner(s): FULLER, RODNEY EVAN
• Application Number:
  US10/070,682
• Time in Patent Office: 1,838 Days
• Field of Search: 359/326, 359/328, 359/332, 359/341.1, 372/5, 372/22, 355/67, 355/71, 355/77
• US Class Current: 355/67
• CPC Class Codes: G02F 1/354 Third or higher harmonic generation
• CPC Class Codes: G03F 7/70025 by lasers
• CPC Class Codes: G03F 7/70041 by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control
• 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: G03F 9/7065 Production of alignment light, e.g. light source, control of coherence, polarization, pulse length, wavelength
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• 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 3/0064 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 3/0092 Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity nonlinear frequency conversion per se G02F1/35
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• 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 3/094015 with pump light recycling, i.e. with reinjection of the unused pump light back into the fiber, e.g. by reflectors or circulators
• 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 3/2375 Hybrid lasers H01S3/07 takes precedence
• CPC Class Codes: H01S 3/2383 Parallel arrangements
• CPC Class Codes: H01S 5/06804 by monitoring an external parameter, e.g. temperature
• CPC Class Codes: H01S 5/0687 : Stabilising the frequency of the laser

Abstract

An exposure apparatus has a light source comprising a laser device that is small and easy to maintain. The laser device comprises a laser oscillator for generating a single-wavelength laser beam (LB3) within a wavelength range including infrared and visible regions; an optical amplifier (18) for amplifying a laser beam (LB3); and a wavelength converter for converting the amplified laser beam into ultraviolet light using a nonlinear optical crystal. The optical amplifier (18) includes a plurality of stages of optical fiber amplifiers (22, 25) for sequential amplification of the laser beam (LB3), and a narrow-band filter (24A) and an isolator (IS3) arranged between optical fiber amplifiers.

Claims

1. An exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and exposes a second object with the ultraviolet light which has passed through the pattern of the first object, wherein

the laser device includes:

a laser light generation section which generates laser light having a single wavelength within a wavelength range ranging from an infrared band to a visible band;

an optical amplification section including plural stages of optical fiber amplifiers which serially amplify the laser light generated by the laser light generation section, and a narrow band filter and an isolator disposed between the plural stages of the optical fiber amplifiers; and

a wavelength conversion section which performs wavelength conversion of the laser light amplified by the optical amplification section into ultraviolet light by using a nonlinear optical crystal.

2. An exposure apparatus as recited in claim 1, wherein

the laser device includes an excitation-light generating light source which generating excitation light which is to be used at least one of the plural stages of the optical fiber amplifiers, and the optical amplifier is formed such that a reflection film which reflects the excitation light is formed at one end of the optical fiber coupled to the narrow band filter.

3. An exposure apparatus as recited in claim 1, wherein

the narrow band filter and the isolator reduce noise of a wavelength corresponding to a phonon sideband.

4. An exposure apparatus as recited in claim 1, wherein

at least three stages of the optical fiber amplifiers are provided, and the narrow band filter and the isolater are respectively provided between the individual optical fiber amplifiers.

5. An exposure apparatus as recited in claim 1, wherein

a gate device, which performs timewise removal of ASE (amplified spontaneous emission), is further provided between the plural stages of the optical fiber amplifiers.

6. An exposure apparatus as recited in claim 1, wherein the laser device includes an optical modulation section which modulates the laser light generated by the laser light generation section into pulsed light and which sets the width of the pulsed light to be wider than a pulsewidth set for obtaining a predetermined wavelength width with the ultraviolet light.

7. An exposure apparatus as recited in claim 12, wherein the laser device includes an optical splitter which splits the laser light generated by the laser light generation section into a plurality of laser light beams, the optical amplification section is independently provided for each of the plural split laser light beams, and the laser device further includes a regulator which regulates an amplification gain of the optical amplification sections so that outputs of the plurality of split laser light beams are substantially uniformalized.

8. An apparatus according to claim 6, wherein

the laser light generation section includes a single wavelength oscillation laser which generates the laser light of a single wavelength, and the laser light generation section pulse-generates the laser light by at least one of the single wavelength oscillation laser and the optical modulation section.

9. An exposure apparatus as recited in claim 1, wherein the optical fiber amplification section is an erbium-doped fiber amplifier and uses laser light having a wavelength of (980±

10) nm as the excitation light for the amplifier.

10. An exposure apparatus as recited in claim 1, wherein a multilayer film filter or a fiber Bragg grating is used for the narrow band filter.

11. An exposure apparatus as recited in claim 1, wherein the laser light generation section includes a single wavelength oscillatory laser which generates the laser light having a single wavelength within a wavelength range ranging from an infrared band to a visible band, and an oscillation-wavelength controller which controls an oscillation wavelength of the generated laser light to be a predetermined wavelength.

12. An exposure apparatus as recited in claim 1, wherein

the laser device further includes an optical splitter which splits the laser light generated by the laser light generation section into a plurality of laser light beams,

the optical amplification section is independently provided for each of the plural split laser light beams, and

the wavelength conversion section performs collective wavelength conversion of a bundle of the laser light beams output from the plural optical amplification sections.

13. An exposure apparatus as recited in claim 12, further comprising a regulator which regulates an amplification gain of the optical amplification sections so that outputs of the plurality of split laser light beams are substantially uniformalized.

14. An exposure apparatus as recited in claim 12, wherein the regulator changes the output of the excitation light used for the optical fiber amplifier in the optical amplification section.

15. An exposure apparatus as recited in claim 1, wherein

the laser light generation section generates single wavelength laser light having a wavelength of near 1.5 μ

m, and

the wavelength conversion section converts a fundamental wave output from the optical amplification section having a wavelength of near 1.5 μ

m into ultraviolet light of an eighth-order harmonic wave or a tenth-order harmonic wave and outputs the converted light.

16. An exposure apparatus as recited in claim 1, wherein

the laser light generation section generates a single wavelength laser light having a wavelength of near 1.1 μ

m, and

the wavelength conversion section converts a fundamental wave output from the optical amplification section having a wavelength of near 1.1 μ

m into ultraviolet light of a seventh-order harmonic wave thereof and outputs the converted light.

17. An exposure apparatus as recited in claim 1, comprising:

an illumination system which radiates ultraviolet light from the laser device onto a mask as the first object; and

a projection optical system which projects an image of a pattern of the mask onto a substrate as the second object.

18. An exposure method using an exposure apparatus as recited in claim 1, comprising using the ultraviolet light output from the laser device to perform alignment between the first object and the second object.

19. A device manufacturing method including transferring a mask pattern onto a substrate by using the exposure apparatus as recited in claims 1.

27. An exposure apparatus as recited in claim 8, wherein the width of the pulsed light modulated by the optical modulation section is 2 to 5 ns.

20. An exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and exposes a second object with the ultraviolet light which has passed through the pattern of the first object, wherein

the laser device includes:

a laser light generation section which generates laser light of a single wavelength, having a single wavelength within a wavelength range ranging from an infrared band to a visible band;

an optical amplification section including plural stages of amplifying optical fibers which serially amplify the laser light generated by the laser light generation section, an excitation-light generating light source which generates excitation light for at least one stage of the amplifying optical fiber of the plural stages of the amplifying optical fibers, a narrow band filter or an isolator disposed between the plural stages of the amplifying optical fibers, and a bypass member which passes the excitation light in parallel to the narrow band filter or the isolator; and

a wavelength conversion section which performs wavelength conversion of the laser light amplified by the optical amplification section into ultraviolet light by using a nonlinear optical crystal.

21. An apparatus according to claim 20, wherein

the laser ligth generation section pulse-generates the laser light and includes an optical modulation section which sets a pulse-width of the laser light to be wider than a pulse-width set for obtaining a predetermined wavelength width with the ultraviolet light.

22. An apparatus according to claim 20, wherein

the plural stages of the amplifying optical fibers include erbium-doped optical fiber amplifiers and use laser light having a wavelength of about 980±

10 nm as the excitation light for the amplifiers.

23. An exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and exposes a second object with the ultraviolet light which has passed through the pattern of the first object, wherein

the laser device includes:

a laser light generation section which generates laser light having a single wavelength within a wavelength range ranging from an infrared band to a visible band;

an optical amplification section including plural stages of optical fiber amplifiers which serially amplify the laser light generated by the laser light generation section, a plurality of excitation-light generating light sources which individually generate excitation lights for each of the plural stages of the optical fiber amplifiers, and a narrow band filter disposed beween the plural stagesof the optical fiber anplifiers, wherein a reflection film which reflects the excitation light is formed at one end of each of the optical fibers coupled to both sides of the narrow band filter; and

a wavelength conversion section which performs wavelength conversion of the laser light amplified by the optical amplification section into ultraviolet light by using a nonlinear optical crystal.

24. An apparatus according to claim 23, wherein

the laser light generation section pulse-generates the light and includes an optical modulation section which sets a pulse-width of the laser light to be wider than a pulse-width set for obtaining a predetermined wavelength width with the ultraviolet light.

25. An apparatus according to claim 23, wherein

the plural stages of the amplifying optical fibers include erbium-doped optical fiber amplifiers and use laser light having a wavelength of about 980±

10 nm as the excitation light for the amplifiers.

26. An exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and exposes a second object with the ultraviolet light which has passed through the pattern of the first object, wherein

the laser device includes:

a laser light generation section which includes a single wavelength oscillatory laser and an optical modulation section and which pulse-generates laser light having a single wavelength within a wavelength range ranging from an infrared band to a visible band;

an optical modulation section which modulates the laser light generated by the laser light generation section with a predetermined repetition frequency into pulsed light having a predetermined width;

an optical amplification section including an optical fiber amplifier which amplifies the laser light which has passed through the optical modulation section; and

a wavelength conversion section which performs wavelength conversion of the laser light amplified by the optical amplification section into ultraviolet light by using a nonlinear optical crystal, wherein

the width of the pulsed light modulated by the optical modulation section is set wider than a pulsewidth set for obtaining a predetermined wavelength width with finally generated ultraviolet light.

28. An apparatus according to claim 26, wherein

the laser light generation section pulse-generates the laser light by at least one of the single wavelength oscillatory laser and the optical modulation section.

29. An apparatus according to claim 26, wherein

the optical amplifier includes an erbium-doped optical fiber amplifier and uses laser light having a wavelength of about 980±

10 nm as an excitation light for the amplifier.

30. An exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and exposes a second object with the ultraviolet light which has passed through the pattern of the first object, wherein

the laser device includes:

a laser light generation section which generates laser light having a single wavelength within a wavelength range ranging from an infrared band to a visible band;

an optical amplification section including an optical fiber amplifier which amplifies the laser light generated by the laser light generation section, a transmitting optical fiber which propagates the laser amplified by the optical fiber amplifier, and a narrow band filter disposed between the optical fiber amplifier and the transmitting optical fiber; and

a wavelength conversion section which performs wavelength conversion of the laser light amplified by the optical amplification section into ultraviolet light by using a nonlinear optical crystal.

31. An exposure apparatus as recited in claim 30, wherein the narrow band filter is concurrently used as a wavelength division multiplexing device for multiplexing which feeds excitation light to the optical fiber amplifier.

32. An apparatus according to claim 30, wherein

the laser light generation section pulse-generates the laser light and includes an optical modulation section which sets a pulse-width of the laser light to be wider than a pulse-width set for obtaining a predetermined wavelength width with the ultraviolet light.

33. An apparatus according to claim 30, wherein

the optical amplifier includes an erbium-doped optical fiber amplifier and uses laser light having a wavelength of about 980±

10 nm as an excitation light for the amplifier.

34. An exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and exposes a second object with the ultraviolet light which has passed through the first object, wherein

the laser device includes:

a laser generation section which generates laser light having a wavelength within a wavelength range ranging from an infrared band to a visible band, an optical splitter which splits the laser light into a plurality of laser light beams, a plurality of optical fiber amplifiers which respectively and independently amplify the plurality of split laser light beams, a wavelength conversion section which performs wavelength conversion of the amplified laser light beams, and

the laser device includes a regulator which regulates an amplification gain at at least one of the plurality of the optical fiber amplifiers so that outputs of the plurality of split laser light beams are substantially uniformalized.

35. An exposure apparatus as recited in claim 34, wherein the regulator controls an excitation-light generating light source which generates excitation light used in the at least one optical fiber amplifier.

36. A method of manufacturing an exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and that expose a second object with the ultraviolet light which has passed through the pattern of the first object, comprising configuring the laser device by disposing, with a predetermined relationship,

a laser light generation section which generates single wavelength laser light in a wavelength range of from an infrared region to a visible region,

an optical amplification section including plural stages of optical fiber amplifiers which serially amplify the laser light generated by the laser light generation section, and a narrow band filter and an isolator disposed between the plural stages of the optical fiber amplifiers, and

a wavelength conversion section which performs wavelength conversion of the laser light amplified by the optical amplification section into ultraviolet light by using a nonlinear optical crystal.

37. A method of manufacturing an exposure apparatus which illuminates a pattern of a first object with ultraviolet light from a laser device and which exposes a second object with the ultraviolet light which has passed through the pattern of the first object, comprising configuring the laser device by disposing, with a predetermined relationship, a laser light generation section which generates single wavelength laser light in a wavelength range of from an infrared region to a visible region;

an optical amplification section including plural stages of amplifying optical fibers which serially amplify the laser light generated by the laser light generation section, an excitation-light generating light source which generates excitation light for at least one stage of the amplifying optical fiber of the plural stages of the amplifying optical fibers, a narrow band filter or an isolator disposed between the plural stages of the amplifying optical fibers, and a bypass member which passes the excitation fight in parallel to the narrow band filter or the isolator; and

a wavelength conversion section which performs wavelength conversion of the laser light amplified by the optical amplification section into ultraviolet light by using a nonlinear optical crystal.

38. An exposure apparatus which illuminates a first object having a pattern with ultraviolet light and exposes a second object with the ultraviolet light from the first object, comprising:

an illumination optical system disposed on an optical path through which the ultraviolet light passes; and

a laser device optically connected to the illumination optical system, wherein

the laser device includes;

a laser light generation section which includes a single wavelength oscillatory laser and generates single wavelength pulsed light in a wavelength range of about 1.51 μ

m to about 1.59 μ

m;

an optical amplification section including an optical fiber amplifier for amplifying the pulsed light and being optically connected to the laser light generation section;

a wavelength conversion section including a plurality of nonlinear optical crystals for performing wavelength conversion of the amplified pulsed light into a wavelength associated with ultraviolet light and being optically connected to the optical amplification section; and

a suppressing section which suppresses expansion of a wavelength width of light originated in a nonlinear effect of an optical element of the laser device between the single wavelength oscillatory laser and the wavelength conversion section.

39. An apparatus according to claim 38, wherein the optical element includes at least the optical fiber amplifier.

40. An apparatus according to claim 39, further comprising a temperature control device which is connected to the wavelength conversion section and which controls a temperature of at least one of the plurality of nonlinear optical crystals.

41. An apparatus according to claim 40, wherein the plurality of nonlinear optical crystals include at least one nonlinear optical crystal used in NCPM (Non-Critical Phase Matching).

42. An apparatus according to claim 41, wherein the laser light generation section generates the pulsed light by at least one of the single wavelength oscillatory laser and an optical modulator.

43. An apparatus according to claim 42, wherein the laser light generation section pulse-generates light having a first pulse-width from the single wavelength oscillation laser and includes an optical modulator which generates the pulsed light having a second pulse-width narrower than the first pulse-width with the pulse-generated light.

44. An apparatus according to claim 38, wherein

the laser light generation section generates the pulsed light by at least one of the single wavelength oscillatory laser and an optical modulator, and

the apparatus further comprises an adjusting device connected to the laser light generation section for adjusting oscillation characteristics of the ultraviolet light generated from the wavelength conversion section.

45. An apparatus according to claim 44, wherein the oscillation characteristics include at least one of intensity, a central wavelength and an oscillation interval of the ultraviolet light.

46. An apparatus according to claim 44, wherein the adjusting device uses a detecting result of light having a wavelength different from the ultraviolet light.

47. A method of manufacturing an exposure apparatus which illuminates a first object having a pattern with ultraviolet light and exposes a second object with the ultraviolet light from the first object, comprising:

providing an illumination optical system to be disposed on an optical path through which the ultraviolet light passes; and

optically connecting a laser device to the illumination optical system, the laser device including;

a laser light generation section which includes a single wavelength oscillatory laser and generates single wavelength pulsed light in a wavelength range of about 1.51 μ

m to about 1.59 μ

m;

an optical amplification section including an optical fiber amplifier for amplifying the pulsed light;

a wavelength conversion section including a plurality of nonlinear optical crystals for performing wavelength conversion of the amplified pulsed light into a wavelength associated with ultraviolet light; and

a suppressing section which suppresses expansion of a wavelength width of light originated via a nonlinear effect of the optical fiber amplifier between the single wavelength oscillatory laser and the wavelength conversion section.