Laser device, wavelength control method for laser device, and method for manufacturing electronic device

Abstract

This laser apparatus comprises: a first wavelength-variable semiconductor laser that outputs a first, continuous-wave laser light; a first amplifier that performs pulsing and amplification of the first laser light to output a first pulsed laser light; a wavelength conversion system which performs wavelength conversion using the first pulsed laser light to output a second pulsed laser light; an excimer amplifier that amplifies the second pulsed laser light to output a third pulsed laser light; a monitor module that measures the wavelength of the third pulsed laser light; and a processor which periodically changes a target wavelength for the third pulsed laser light, and controls a current for changing the wavelength of the first semiconductor laser on the basis of a measurement value of the wavelength of the third pulsed laser light that has been output with the same target wavelength so that the wavelength of the third pulsed laser light becomes the target wavelength.

Description

[Technical Field]

[0001] The present disclosure relates to a laser device, a wavelength control method for a laser device, and a manufacturing method for an electronic device. [Background technology]

[0002] In recent years, semiconductor exposure devices have been required to improve their resolution in response to the miniaturization and high integration of semiconductor integrated circuits. To this end, the wavelength of light emitted from exposure light sources has been shortened. For example, KrF excimer laser devices that output laser light with a wavelength of approximately 248 nm and ArF excimer laser devices that output laser light with a wavelength of approximately 193 nm are used as gas laser devices for exposure.

[0003] The spectral linewidth of the spontaneously oscillating light from KrF excimer laser devices and ArF excimer laser devices is as wide as 350 to 400 pm. Therefore, if a projection lens is constructed using a material that transmits ultraviolet light, such as KrF and ArF laser light, chromatic aberration may occur. As a result, resolution may decrease. Therefore, it is necessary to narrow the spectral linewidth of the laser light output from the gas laser device to a level where chromatic aberration is negligible. Therefore, a line narrowing module (LNM) containing a line narrowing element (e.g., an etalon or grating) may be installed inside the laser resonator of the gas laser device to narrow the spectral linewidth. Hereinafter, a gas laser device with a narrowed spectral linewidth is referred to as a line narrowing gas laser device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2021 / 0226414 [Patent Document 2] International Publication No. 2021 / 015919 [Patent Document 3] Overview of International Publication No. 2020 / 231946

[0005] A laser device according to one aspect of the present disclosure includes: a wavelength-tunable first semiconductor laser that outputs a continuous wave first laser beam; a first amplifier that pulses and amplifies the first laser beam to output the first pulsed laser beam; a wavelength conversion system that outputs a second pulsed laser beam by wavelength conversion using the first pulsed laser beam; an excimer amplifier that amplifies the second pulsed laser beam to output a third pulsed laser beam; a monitor module that measures the wavelength of the third pulsed laser beam; and a processor that periodically changes a target wavelength of the third pulsed laser beam, and controls a current to change the wavelength of the first semiconductor laser based on a measured value of the wavelength of the third pulsed laser beam output at the same target wavelength so that the wavelength of the third pulsed laser beam becomes the target wavelength.

[0006] A wavelength control method for a laser device according to one aspect of the present disclosure is a wavelength control method for a laser device, the wavelength control method including: outputting a continuous wave first laser beam from a first semiconductor laser; pulsing and amplifying the first laser beam to output the first pulsed laser beam; outputting a second pulsed laser beam by wavelength conversion using the first pulsed laser beam; amplifying the second pulsed laser beam to output a third pulsed laser beam; measuring a wavelength of the third pulsed laser beam; periodically changing a target wavelength of the third pulsed laser beam; and controlling a current for changing the wavelength of the first semiconductor laser based on a measured value of the wavelength of the third pulsed laser beam output at the same target wavelength so that the wavelength of the third pulsed laser beam becomes the target wavelength.

[0007] a wavelength conversion system that performs wavelength conversion using the first pulsed laser beam to output a second pulsed laser beam; an excimer amplifier that amplifies the second pulsed laser beam to output a third pulsed laser beam; a monitor module that measures the wavelength of the third pulsed laser beam; and a processor that periodically changes a target wavelength of the third pulsed laser beam and controls a current for changing the wavelength of the first semiconductor laser based on a measured value of the wavelength of the third pulsed laser beam outputted at the same target wavelength so that the wavelength of the third pulsed laser beam becomes the target wavelength; [Brief explanation of the drawings]

[0008] Some embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a graph for explaining two-wavelength parameters in the case of two-wavelength exposure. [Figure 2] FIG. 2 is a graph for explaining multi-wavelength parameters in the case of multi-wavelength exposure. [Figure 3] FIG. 3 is a diagram schematically showing the configuration of an exposure system. [Figure 4] FIG. 4 is a top view showing the configuration of a laser device of a comparative example. [Figure 5] FIG. 5 is a side view showing the configuration of a laser device of a comparative example. [Figure 6] FIG. 6 is a diagram showing the configuration of an exposure system according to the first embodiment. [Figure 7] FIG. 7 is a flowchart showing the processing procedure of the laser control processor in the first embodiment. [Figure 8]FIG. 8 is a timing chart showing the relationship between the pulse number and wavelength of the excimer laser light output from the laser device in the first embodiment. [Figure 9] FIG. 9 is a timing chart showing the relationship between the pulse number of the excimer laser light output from the laser device in the first embodiment and the current value of the semiconductor laser element. [Figure 10] FIG. 10 is a diagram schematically illustrating a configuration example of a first semiconductor system. [Figure 11] FIG. 11 is a graph showing the spectrum of the pulsed laser light output from the SOA. [Figure 12] FIG. 12 is a flowchart showing the processing steps of the semiconductor laser control processor when controlling the temperature of the semiconductor laser element based on the target center wavelength. [Figure 13] FIG. 13 is a graph showing the relationship between the set temperature of the semiconductor laser element and the wavelength after excimer amplification in the case of a reference current value. [Figure 14] FIG. 14 is a flowchart showing the processing steps of the semiconductor laser control processor when controlling the temperature of the semiconductor laser element based on the average current value. [Figure 15] FIG. 15 is a diagram schematically illustrating an example of the configuration of a wavelength conversion system. [Figure 16] FIG. 16 is a graph showing the relationship between the wavelength λ after wavelength conversion and the wavelength conversion efficiency η. [Figure 17] FIG. 17 is a diagram schematically illustrating an example of the configuration of a temperature adjustment system for a nonlinear crystal. [Figure 18] FIG. 18 is a graph showing the relationship between the target central wavelength after wavelength conversion and the temperature at which the wavelength conversion efficiency is maximized. [Figure 19] FIG. 19 is a flowchart showing the processing procedure of the laser control processor when controlling the wavelength conversion system. [Figure 20] FIG. 20 is a graph showing the relationship between wavelength after excimer amplification and wavelength conversion efficiency. [Figure 21] FIG. 21 is a graph showing the relationship between wavelength after excimer amplification and wavelength conversion efficiency. [Figure 22] FIG. 22 is a diagram showing the configuration of an exposure system according to the second embodiment. [Figure 23] FIG. 23 is a flowchart showing the processing procedure of the laser control processor in the second embodiment. [Figure 24] FIG. 24 is a flowchart showing the processing steps of the semiconductor laser control processor when controlling the temperature of the semiconductor laser element based on the target center wavelength. [Figure 25] FIG. 25 is a flowchart showing the processing steps of the semiconductor laser control processor when controlling the temperature of the semiconductor laser element based on the average current value. [Figure 26] FIG. 26 is a flowchart showing the processing procedure of the laser control processor when controlling the wavelength conversion system. [Figure 27] FIG. 27 is a graph showing the relationship between the wavelength λ after excimer amplification and the wavelength conversion efficiency. [Figure 28] FIG. 28 is a graph showing the relationship between the wavelength λ after excimer amplification and the wavelength conversion efficiency. [Figure 29] FIG. 29 is a flowchart showing the processing procedure of the laser control processor when controlling the wavelength conversion system. [Figure 30] FIG. 30 is a flowchart showing the processing procedure of the laser control processor in the case of dual wavelength exposure in the third embodiment. [Figure 31] FIG. 31 is a flowchart showing the processing procedure of the laser control processor in the case of dual wavelength exposure in the third embodiment. [Figure 32] FIG. 32 is a graph showing the relationship between the wavelength after excimer amplification and the current value of the semiconductor laser element. [Figure 33] FIG. 33 is a flowchart showing the processing procedure of the laser control processor in the case of multi-wavelength exposure in the third embodiment. [Figure 34] FIG. 34 is a flowchart showing the processing procedure of the laser control processor in the case of multi-wavelength exposure in the third embodiment. [Figure 35]FIG. 35 is a diagram showing a schematic diagram of a modification of the configuration of a solid seeder. [Figure 36] FIG. 36 is a diagram schematically illustrating an example of the configuration of a semiconductor laser system. [Figure 37] FIG. 37 is a diagram schematically illustrating an example of the configuration of a semiconductor laser system. [Figure 38] FIG. 38 is a diagram schematically showing an example of the configuration of an exposure apparatus. Embodiment

[0009] -table of contents- 1. Explanation of terms 2. Comparative Example 2.1 Exposure system 2.1.1 Configuration 2.1.2 Operation 2.2 Laser device according to a comparative example 2.2.1 Configuration 2.2.2 Operation 3. Challenges 4. Embodiment 1 4.1 Laser device 4.1.1 Configuration 4.1.2 Operation 4.1.2.1 Normal control 4.1.2.2 Dual wavelength control 4.1.3 Actions and Effects 4.1.4 Other 4.2 Semiconductor laser system 4.2.1 Configuration 4.2.2 Operation 4.2.3 Other 4.3 Temperature control of semiconductor laser by laser control processor 4.3.1 Flowchart example 1 4.3.2 Flowchart example 2 4.3.3 Actions and Effects 4.4 Wavelength conversion system 4.4.1 Configuration 4.4.2 Operation 4.5 Temperature control system for nonlinear crystals 4.5.1 Configuration 4.5.2 Operation 4.5.3 Other 4.6 Wavelength conversion system 4.6.1 Flowchart example 4.6.2 Operation 4.6.3 Actions and Effects 5. Embodiment 2 5.1 Configuration 5.2 Laser Control Processor Flowchart 5.3 Temperature control of semiconductor laser 5.3.1 Flowchart Example 1 5.3.2 Flowchart example 2 5.3.3 Actions and Effects 5.4 Wavelength conversion system 5.4.1 Flowchart example 5.4.2 Flowchart example 6. Embodiment 3 6.1 Dual wavelength exposure 6.1.1 Flowchart example 6.1.2 Flowchart example 6.2 Multi-wavelength exposure 6.2.1 Flowchart example 6.2.2 Flowchart example 7. Embodiment 4 7.1 Configuration 7.2 Operation 7.3 Other 8. Embodiment 5 8.1 Configuration 8.2 Operation 8.3 Other 8.4 Actions and Effects 9. Embodiment 6 9.1 Configuration 9.2 Operation 9.3 Actions and Effects 10. Electronic device manufacturing method 11.Other

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show some examples of the present disclosure and do not limit the content of the present disclosure. Furthermore, not all of the configurations and operations described in each embodiment are necessarily essential as the configurations and operations of the present disclosure. Note that the same components are given the same reference symbols, and redundant explanations will be omitted.

[0011] 1. Explanation of terms In this specification, "two wavelength exposure" means that the wavelength is λ S and λ L This refers to two-wavelength exposure achieved by alternately oscillating the laser at two wavelengths.

[0012] FIG. 1 is a graph for explaining two-wavelength parameters in the case of dual-wavelength exposure. In FIG. 1, the horizontal axis represents wavelength λ and the vertical axis represents light intensity In. As shown in FIG. 1, the wavelength on the short wavelength side in dual-wavelength exposure is λ S , the wavelength on the long wavelength side is λ L The central wavelength λc of the two-wavelength spectrum is λc=(λ L +λ S ) / 2.

[0013] In this specification, "multi-wavelength exposure" refers to multi-wavelength exposure performed by periodically changing the oscillation wavelength by oscillating the laser with wavelengths λ(1), λ(2), λ(3), ..., λ(n) for each pulse.

[0014] Figure 2 is a graph explaining the multi-wavelength parameters in the case of multi-wavelength exposure. In Figure 2, the horizontal axis represents wavelength λ, and the vertical axis represents light intensity In. As shown in Figure 2, the wavelengths in multi-wavelength exposure are wavelength λ(1), wavelength λ(2), ..., wavelength λ(k), ..., wavelength λ(n), in order from the shortest wavelength. The central wavelength λc of the multi-wavelength spectrum is λc = {λ(1) + λ(2) + λ(3) + ... + λ(n)} / n.

[0015] 2. Comparative Example 2.1 Overview of the exposure system 2.1.1 Configuration 3 is a diagram showing a schematic configuration of an exposure system. The exposure system includes a laser apparatus 10 and an exposure apparatus 300. The laser apparatus 10 includes a laser control processor 12. In this specification, a processor refers to a processing device that includes a storage device in which a control program is stored and a CPU (Central Processing Unit) that executes the control program. The processor is specially configured or programmed to execute various processes included in the present disclosure.

[0016] The laser device 10 is configured to output a pulsed laser beam having a tunable oscillation wavelength toward the exposure device 300. The configuration of the laser device 10 will be described later (FIGS. 4 and 5).

[0017] The exposure apparatus 300 includes a beam delivery unit (BDU) 302, a high-reflection mirror 304, an illumination optical system 306, a reticle stage RT, a projection optical system 308, a wafer stage WS, and an exposure control processor 310. A wafer holder WH is provided on the wafer stage WS, and a wafer W is placed on the wafer holder WH.

[0018] The BDU 302 is an optical system that transmits pulsed laser light from the laser device 10 to the exposure device 300. The high-reflection mirror 304 is disposed so that the pulsed laser light that has passed through the BDU 302 enters the illumination optical system 306.

[0019] The illumination optical system 306 is an optical system that shapes the pulsed laser light beam incident from the laser device 10 and guides it to the reticle R placed on the reticle stage RT. The illumination optical system 306 shapes the pulsed laser light beam so that it has a generally rectangular cross section and a generally uniform light intensity distribution, and illuminates the reticle pattern on the reticle R. The projection optical system 308 reduces and projects the pulsed laser light that has passed through the reticle R, forming an image on the wafer W on the wafer holder WH. The wafer W is a photosensitive substrate such as a semiconductor wafer coated with a resist film.

[0020] The exposure control processor 310 is a processing device that includes a storage device in which a control program is stored and a CPU that executes the control program. The exposure control processor 310 oversees the control of the exposure apparatus 300. The exposure control processor 310 is connected to the reticle stage RT and the wafer stage WS. The exposure control processor 310 is also connected to the laser control processor 12.

[0021] 2.1.2 Operation The exposure control processor 310 determines the target short wavelength λ S t and target long wavelength λ L The laser control processor 12 transmits various parameters including the target pulse energy Et, the target pulse energy Et, and the light emission trigger signal Tr to the laser control processor 12. The laser control processor 12 controls the laser device 10 in accordance with these parameters and signals. That is, the laser control processor 12 controls the laser device 10 so that the wavelength λ of the pulsed laser light output from the laser device 10 is equal to or smaller than the target short wavelength λ. S t or target long wavelength λ L The target wavelength is periodically changed to control the oscillation wavelength so that the wavelength becomes equal to t, and the excitation intensity is controlled so that the pulse energy E becomes equal to the target pulse energy Et, and pulse laser light is output in accordance with the light emission trigger signal Tr.

[0022] In this way, the laser device 10 can achieve a target short wavelength λ at the target pulse energy Et. S t and target long wavelength λ L Two-wavelength oscillation of t is performed, and pulsed laser light is output in accordance with the light emission trigger signal Tr.

[0023] Furthermore, the laser control processor 12 transmits various data to the exposure control processor 310. The various data includes measurement data such as the wavelength and pulse energy of the pulse laser light output in accordance with the light emission trigger signal Tr.

[0024] The exposure control processor 310 synchronizes the reticle stage RT and the wafer holder WH on the wafer stage WS and translates them in opposite directions, thereby exposing the wafer W to pulsed laser light that reflects the reticle pattern.

[0025] When forming a 3D NAND pattern or a contact hole pattern, exposure is performed so that the waveform of the integrated spectrum becomes a desired two-wavelength spectrum in order to ensure the depth of focus.

[0026] 2.2 Laser device according to a comparative example 2.2.1 Configuration 4 and 5 are a top view and a side view showing the configuration of a laser device 10 according to a comparative example. The comparative example of the present disclosure is a configuration that the applicant recognizes as being known only by the applicant, and is not a publicly known example that the applicant acknowledges.

[0027] The laser device 10 shown in Figures 4 and 5 is a single-wavelength, narrow-band excimer laser device, and includes a laser control processor 12, a chamber 14, an LNM 20, an output coupling mirror 30, a beam splitter 32, a monitor module 34, and an exit shutter 36.

[0028] The LNM 20 includes a first prism 22, a second prism 24, a rotation stage 26, and a grating 28. The first prism 22, the second prism 24, and the grating 28 are supported by holders 22a, 24a, and 28a, respectively. The first prism 22 and the second prism 24 are arranged to function as a beam expander. The grating 28 is Littrow-aligned so that the angle of incidence of the light beam incident on the grating 28 from the second prism 24 matches the diffraction angle of the diffracted light of the desired wavelength.

[0029] The second prism 24 is mounted on a rotation stage 26 via a holder 24a. The rotation stage 26 is a stage that can be rotated with a relatively high response speed using a piezoelectric element (not shown). The second prism 24 is positioned so that the angle of incidence on the grating 28 changes when rotated around the V axis by the rotation stage 26.

[0030] The output coupling mirror 30 is arranged to form an optical resonator together with the LNM 20. The chamber 14 is arranged on the optical path of the optical resonator.

[0031] Chamber 14 includes windows 16a and 16b and a pair of electrodes 18a and 18b. A laser gas is supplied from a gas supply device (not shown) into chamber 14. The laser gas may be, for example, an excimer laser gas containing Ar gas or Kr gas as a rare gas, F gas as a halogen gas, and Ne gas as a buffer gas.

[0032] The electrodes 18a and 18b are arranged in the chamber 14 facing each other in the V direction, with the longitudinal direction of the electrodes 18a and 18b coinciding with the optical path of the optical resonator. The laser device 10 includes a pulse power module (PPM) and a charger (not shown). The PPM includes a switch and a charging capacitor, and is connected to the electrode 18b via a feedthrough made of an electrical insulating member (not shown). The electrode 18a is connected to the grounded chamber 14. The charger charges the charging capacitor of the PPM in accordance with commands from the laser control processor 12.

[0033] The windows 16a and 16b are arranged so that pulsed laser light excited by discharge between the electrodes 18a and 18b and amplified passes through them.

[0034] The output coupling mirror 30 is coated with a film that reflects part of the pulsed laser light and transmits part of it. The beam splitter 32 is disposed on the optical path of the pulsed laser light output from the output coupling mirror 30. The beam splitter 32 is disposed so that the reflected light from the beam splitter 32 enters the monitor module 34. Note that the beam splitter 32 may be included in the monitor module 34.

[0035] The monitor module 34 includes a pulse energy measuring instrument and a spectrum monitor. The pulse energy measuring instrument includes an optical sensor (not shown). The optical sensor may be a photodiode that is resistant to ultraviolet light and has excellent high-speed response. The spectrum monitor may detect wavelengths using, for example, an etalon spectrometer.

[0036] The exit shutter 36 is disposed on the optical path of the pulsed laser light output from the laser device 10 to the outside, and is configured to be able to output the pulsed laser light to the outside and to block the light. The pulsed laser light that has passed through the beam splitter 32 is output from the laser device 10 via the exit shutter 36.

[0037] 2.2.2 Operation The laser control processor 12 determines the target short wavelength λ S t and target long wavelength λ L The laser control processor 12 also receives a light emission trigger signal Tr.

[0038] The laser control processor 12 controls the voltage applied to the electrode 18b based on the received target pulse energy Et, including feedback control based on the pulse energy measured by the monitor module 34.

[0039] Under the control of the laser control processor 12, a pulsed high voltage is applied to electrode 18B. When high voltage is applied to electrode 18B, a discharge occurs in the discharge space between electrodes 18a and 18b. The energy of this discharge excites the laser gas in chamber 14 and causes it to transition to a higher energy level. When the excited laser gas subsequently transitions to a lower energy level, it emits light with a wavelength corresponding to the difference in energy levels.

[0040] Light generated within chamber 14 exits chamber 14 as a light beam through windows 16a and 16b. The light beam exiting window 16a has its beam width expanded by first prism 22 and second prism 24 in a plane parallel to the HZ plane, which is a plane perpendicular to the V axis. The light beam transmitted through first prism 22 and second prism 24 enters grating 28.

[0041] A light beam incident on the grating 28 is reflected by the multiple grooves of the grating 28 and diffracted in a direction according to the wavelength of the light.

[0042] The first prism 22 and the second prism 24 reduce the beam width of the light beam returned from the grating 28 in a plane parallel to the HZ plane, and return the light beam to the inside of the chamber 14 through the window 16a.

[0043] The output coupling mirror 30 transmits a portion of the light beam emitted from the window 16 b and reflects another portion back into the chamber 14 .

[0044] In this way, the light beam emitted from chamber 14 travels back and forth between LNM 20 and output coupling mirror 30. This light beam is amplified each time it passes through the discharge space in chamber 14. In addition, this light beam is narrowed in band each time it is reflected by LNM 20. The laser-oscillated, narrowed-band light beam is output from output coupling mirror 30 as pulsed laser light.

[0045] The monitor module 34 measures the pulse energy and wavelength of the pulsed laser light reflected by the beam splitter 32 and transmits the measured pulse energy and wavelength to the laser control processor 12 .

[0046] The pulsed laser light transmitted through the beam splitter 32 is output from the laser device 10 via an exit shutter 36 .

[0047] The laser control processor 12 controls the voltage applied to the electrode 18B based on the received target pulse energy Et, including feedback control based on the pulse energy measured by the monitor module 34.

[0048] The laser control processor 12 changes the oscillation wavelength by controlling the angle of incidence on the grating 28 using the rotation stage 26 on which the second prism 24 is installed. The laser control processor 12 measures the wavelength using a spectrum monitor 126 (see FIG. 6) in the monitor module 34 and calculates the target wavelength (λ S and λ L ) for each pulse. By controlling in this way, the oscillation wavelength of the pulsed laser light output from the laser device 10 is adjusted to the target short wavelength λ S t and target long wavelength λ L t and is controlled.

[0049] 3. Challenges In order to generate an exposure spectrum waveform with two wavelengths, it was necessary to change the wavelength for each pulse with high precision. Also, when an optical element such as the second prism 24 of the LNM 20 is rotated by the rotation stage 26 for each pulse, as the repetition frequency (4 kHz or more) of the laser device 10 increases, it becomes difficult to change the wavelength of the output pulse laser light to the two target wavelengths (λ S t and λ L t), it was difficult to stabilize each with high precision.

[0050] 4. Embodiment 1 The laser device includes a solid-state seeder and an excimer amplifier, and the spectrum of the pulsed laser light output from the laser device is a two-wavelength spectrum, and the target shortest wavelength λ S t, the longest wavelength of the target, λ L Here is an example where t is used.

[0051] 4.1 Laser device 4.1.1 Configuration 6 is a diagram showing the configuration of the exposure system according to embodiment 1. The exposure system includes a laser apparatus 100 and an exposure apparatus 300.

[0052] The laser device 100 includes a laser control processor 12A, a monitor module 34A, a solid-state seeder 102 serving as a master oscillator (MO), and an excimer amplifier 112 serving as a power amplifier (PA).

[0053] The solid-state seeder 102 includes a semiconductor laser system 104 that outputs pulsed laser light, a solid-state amplifier 106 that amplifies the pulsed laser light, a wavelength conversion system 108, and a solid-state seeder control processor 110.

[0054] The semiconductor laser system 104 includes a distributed feedback semiconductor laser 132 (see FIG. 10) that outputs a CW (Continuous Wave) laser beam having a wavelength of approximately 773.6 nm, and an SOA (Semiconductor Optical Amplifier) ​​136 (see FIG. 10), which is a semiconductor optical amplifier. The semiconductor laser 132 is configured so that the oscillation wavelength can be tuned by controlling the temperature of a semiconductor laser element 138 (see FIG. 10) and / or the value of the current flowing through the semiconductor laser element 138.

[0055] The SOA 136 pulses and amplifies the CW laser light output from the semiconductor laser 132. By passing a pulse current through the SOA 136, the SOA 136 pulse-amplifies the CW laser light and outputs pulse-amplified pulsed laser light PL1. The SOA 136 in the first embodiment is an example of a "first amplifier" in the present disclosure.

[0056] The solid-state amplifier 106 includes a titanium sapphire crystal (not shown) and a pumping pulse laser (not shown). The titanium sapphire crystal is placed on the optical path of the pulsed laser light pulse-amplified by the SOA 136. The pumping pulse laser is a laser device that outputs second harmonic light of a YLF laser. YLF (yttrium lithium fluoride) is a solid-state laser crystal expressed by the chemical formula LiYF4.

[0057] The wavelength conversion system 108 includes a nonlinear crystal and converts the wavelength of the incident pulsed laser light to generate fourth harmonic light. The configuration of the wavelength conversion system 108 will be described later (see FIG. 15).

[0058] The solid state seeder control processor 110 controls the semiconductor laser system 104 and the solid state amplifier 106 based on input from the laser control processor 12A.

[0059] The excimer amplifier 112 includes a chamber 113, a pulsed power module (PPM) 117, a charger 119, a convex mirror 120, and a concave mirror 122. The chamber 113 includes ArF laser gas, windows 114a and 114b, a pair of electrodes 115a and 115b, and an electrical insulating member 116.

[0060] The PPM 117 includes a switch 118 and a charging capacitor (not shown). The PPM 117 is connected to the electrode 115b via a feedthrough in the electrical insulating member 116 of the chamber 113.

[0061] The charger 119 holds electrical energy to be supplied to the PPM 117. The charger 119 is connected to a charging capacitor (not shown). The electrode 115a is connected to a ground potential.

[0062] The convex mirror 120 and the concave mirror 122 are arranged so that the pulsed laser light PL2 output from the wavelength conversion system 108 passes through the discharge space between the electrodes 115a and 115b three times to expand the beam.

[0063] The monitor module 34A includes beam splitters 32A and 124, a spectrum monitor 126, and an optical sensor 128. The beam splitter 32A is disposed on the optical path of the pulsed laser beam PL3 output from the excimer amplifier 112 so that the pulsed laser beam PL3 is reflected by the beam splitter 32A and enters the beam splitter 124. The beam splitter 32A may be disposed outside the monitor module 34A, similar to the beam splitter 32 shown in FIG. 4.

[0064] The beam splitter 124 is disposed so that the pulsed laser light PL 3 reflected by the beam splitter 124 enters the spectrum monitor 126 , and so that the pulsed laser light PL 3 transmitted through the beam splitter 124 enters the optical sensor 128 .

[0065] The spectrum monitor 126 monitors the spectrum of the incident pulsed laser beam and detects the oscillation wavelength of the incident pulsed laser beam. The spectrum monitor 126 may be, for example, an etalon spectrometer. The etalon spectrometer includes a diffuser plate for diffusing the sample light, an etalon, a condenser lens disposed on the exit side of the etalon, and a photodiode array disposed on the focal plane of the condenser lens for detecting the interference fringe pattern, and can detect the wavelength by measuring the diameter of the interference fringes. The optical sensor 128 detects the pulse energy of the incident pulsed laser beam. The optical sensor 128 may be, for example, a photodiode.

[0066] 4.1.2 Operation 4.1.2.1 Normal control

[0067] A first continuous wave laser beam having a wavelength of approximately 773.6 nm is output from the semiconductor laser element 138. When a pulse current is passed through the SOA 136 in response to a trigger signal Tr2, the SOA 136 is pulse-amplified and outputs a pulsed laser beam PL1. The pulsed laser beam PL1 in the first embodiment is an example of the "first pulsed laser beam" in the present disclosure.

[0068] This pulsed laser light is further amplified by a solid-state amplifier 106 .

[0069] The wavelength conversion system 108 converts the pulsed laser light amplified by the solid-state amplifier 106 into fourth harmonic light with a wavelength of approximately 193.4 nm, and outputs the pulsed laser light PL2. The pulsed laser light PL2 in the first embodiment is an example of the "second pulsed laser light" in the present disclosure. The fourth harmonic light in the first embodiment is an example of the "first harmonic light" in the present disclosure.

[0070] The wavelength of the pulsed laser light PL2 output from the solid-state seeder 102 can be tuned within a range of approximately 193.2 nm to 193.5 nm, which is the amplification wavelength band of the excimer amplifier 112.

[0071] A trigger signal Tr1 is input to the switch 118 of the PPM 117, and a trigger signal Tr2 is input to the SOA 136 and the pumping pulse laser so that a discharge occurs in synchronization with the pulse laser light PL2 output from the solid seeder 102 entering the discharge space in the chamber 113 of the excimer amplifier 112.

[0072] As a result, the pulsed laser light PL2 output from the solid-state seeder 102 is three-pass amplified by the excimer amplifier 112. The excimer amplifier 112 outputs the pulsed laser light PL3. The pulsed laser light PL3 ​​in the first embodiment is an example of the "third pulsed laser light" in the present disclosure.

[0073] The pulsed laser light PL3 ​​is sampled by the beam splitter 32A of the monitor module 34A, and the pulse energy E and wavelength λ are measured.

[0074] The laser control processor 12A and the solid-state seeder control processor 110 control the oscillation wavelength of the semiconductor laser element 138 of the semiconductor laser system 104 so that the wavelength λ of the pulsed laser light PL3 ​​output from the excimer amplifier 112 and measured approaches a target value.

[0075] The laser control processor 12A and the solid-state seeder control processor 110 control the charging voltage of the charger 119 so that the pulse energy E of the pulsed laser light PL3 ​​output from the excimer amplifier 112 and measured approaches a target value.

[0076] 4.1.2.2 Dual wavelength control 7 is a flowchart showing the processing procedure of the laser control processor 12A in embodiment 1. The processing procedure of the laser control processor 12A in embodiment 1 is an example of the "method for controlling wavelength of a laser device" in the present disclosure.

[0077] In step S11, the laser control processor 12A reads the target two-wavelength control parameter data from the exposure control processor 310. The target two-wavelength control parameter data includes the target short wavelength λ S t and target long wavelength λ L Contains t.

[0078] In step S12, the laser control processor 12A determines the current value I S and the current value I at long wavelength L and the initial values ​​I S 0 and I L 0. That is, the laser control processor 12A sets I S =I S 0, I L =I L Set to 0.

[0079] In step S13, the laser control processor 12A sets the command current value I of the semiconductor laser 132 to I S That is, the laser control processor 12A sets I=I S Set to.

[0080] In step S14, the laser control processor 12A determines whether or not excimer laser light has been detected by the spectrum monitor 126. If excimer laser light has not been detected (step S14: No), the laser control processor 12A waits until excimer laser light is detected. If excimer laser light has been detected (step S14: Yes), the laser control processor 12A proceeds to step S15.

[0081] In step S15, the laser control processor 12A detects the wavelength λ of the excimer laser light on the short wavelength side in the spectrum monitor 126. S Measure.

[0082] In step S16, the laser control processor 12A calculates the wavelength λ measured in step S15. S and the target short wavelength λ S Difference from t δλ S That is, the laser control processor 12A calculates δλ S =λ S -λ S Calculate t.

[0083] In step S17, the laser control processor 12A calculates the δλ calculated in step S16. S The current value I of the semiconductor laser 132 approaches 0. S Calculate D.

[0084] In step S18, the laser control processor 12A determines the current value I S The current value I calculated in step S17 S D. That is, the laser control processor 12A sets I S =I S Let's call it D.

[0085] In this way, the processes in steps S13 to S18 are wavelength measurement and control for short wavelengths.

[0086] In step S19, the laser control processor 12A sets the command current value I of the semiconductor laser 132 to I L That is, the laser control processor 12A sets I=I L Set to.

[0087] In step S20, the laser control processor 12A determines whether or not excimer laser light has been detected by the spectrum monitor 126. If excimer laser light has not been detected (step S20: No), the laser control processor 12A waits until excimer laser light is detected. If excimer laser light has been detected (step S20: Yes), the laser control processor 12A proceeds to step S21. In step S21, the laser control processor 12A detects the wavelength λ of the excimer laser light on the long wavelength side in the spectrum monitor 126. L Measure.

[0088] In step S22, the laser control processor 12A calculates the wavelength λ measured in step S21. L and the target long wavelength λ L Difference from t δλ L That is, the laser control processor 12A calculates δλ L =λ L -λ L Calculate t.

[0089] In step S23, the laser control processor 12A calculates the δλ calculated in step S22. L The current value I of the semiconductor laser 132 approaches 0. L Calculate D.

[0090] In step S24, the laser control processor 12A determines the current value I L The current value I calculated in step S23 L D. That is, the laser control processor 12A sets I L =I L Let's call it D.

[0091] In this way, the processes in steps S19 to S24 are wavelength measurement and control for long wavelengths.

[0092] In step S25, the laser control processor 12A determines whether or not to continue the two-wavelength control. If the two-wavelength control is to be continued (step S25: Yes), the laser control processor 12A proceeds to step S26. If the two-wavelength control is not to be continued (step S25: No), the laser control processor 12A ends the processing of this flowchart. In step S26, the laser control processor 12A determines whether or not to update the dual-wavelength control parameter. If the dual-wavelength control parameter is not to be updated (step S26: No), the laser control processor 12A returns the process to step S13. If the dual-wavelength control parameter is to be updated (step S26: Yes), the laser control processor 12A returns the process to step S11.

[0093] 8 is a timing chart showing the relationship between the number of pulses and wavelength of the excimer laser light output from the laser device 100 in the first embodiment. In FIG. 8, the horizontal axis represents the number of pulses (or time), and the vertical axis represents the wavelength. As shown in FIG. 8, the laser device 100 changes the wavelength λ for each pulse. S t excimer laser light and wavelength λ L The excimer laser light of wavelength λ is alternately output. S The excimer laser beam of wavelength t is output, and the even-numbered pulses have a wavelength λ L t of excimer laser light is output.

[0094] 9 is a timing chart showing the relationship between the number of pulses of the excimer laser light output from the laser device 100 in the first embodiment and the current value of the semiconductor laser 132. In FIG. 9, the horizontal axis represents the number of pulses (or time), and the vertical axis represents the current value. As shown in FIG. 9, the laser device 100 sets the current value of the semiconductor laser 132 at a current value I S and the current value I at long wavelength L Here, the odd-numbered pulses have a current value IS and the even-numbered pulses are controlled to the current value I L Control to.

[0095] Target short wavelength λ S t and target long wavelength λ L The wavelength control when t is periodically changed is performed as follows.

[0096] The laser device 100 emits light at a wavelength λ on the short wavelength side of the two-wavelength spectrum. S and the current value I of the semiconductor laser 132 when outputting a short wavelength. S That is, the laser control processor 12A feeds back the target short wavelength λ S When outputting laser light of t, the nearest target short wavelength λ S The wavelength λ of the laser light emitted at t S Based on the measured value, the current value I of the semiconductor laser 132 is S Control.

[0097] The laser device 100 also emits light at a wavelength λ on the long wavelength side of the two-wavelength spectrum. L and the current value I of the semiconductor laser 132 when outputting a long wavelength. L That is, the laser control processor 12A feeds back the target long wavelength λ L When outputting laser light of t, the nearest same target long wavelength λ L The wavelength λ of the laser light emitted at t L Based on the measured value, the current value I of the semiconductor laser 132 is L Control.

[0098] 4.1.3 Actions and Effects In a laser device 100 including a solid-state seeder 102 including a semiconductor laser 132 and an excimer amplifier 112, the wavelength λ measured for each pulse alternately falls short of the target short wavelength λ. S t and target long wavelength λ L The current value flowing through the semiconductor laser 132 is controlled so that the wavelengths approach t, ​​respectively. This enables highly accurate two-wavelength exposure even at a repetition rate of 4 kHz or more.

[0099] 4.1.4 Other In the first embodiment, the CW light from the semiconductor laser 132 is converted into a pulsed laser light by passing a pulsed current through the SOA 136, but the method for generating the pulsed laser light is not limited to this example. For example, the CW light from the semiconductor laser 132 may be amplified into a pulsed laser light by exciting the pumping light of the titanium sapphire crystal of the solid-state amplifier 106 with the pulsed light.

[0100] The solid-state seeder 102 may include a CW semiconductor laser element and a pulsator, and may include a system for changing the wavelength by controlling the current flowing through the semiconductor laser element. Alternatively, the system may use an optical shutter to generate optical pulses instead of the SOA 136. For example, the optical shutter may be a combination of an EO (Electro-Optical) Pockels cell and a polarizer.

[0101] In the first embodiment, an example of a three-pass amplifier is shown as an amplifier, but the amplifier is not limited to a multi-pass amplifier, and may be, for example, an amplifier equipped with an optical resonator such as a Fabry-Perot resonator or a ring resonator.

[0102] In the first embodiment, an example of a solid-state seeder and an ArF excimer amplifier is shown, but the present invention is not limited to this embodiment. A combination of an excimer amplifier containing KrF laser gas and a solid-state seeder oscillating in the amplification wavelength band of the KrF excimer may also be used. Specifically, the solid-state seeder may be a semiconductor laser system outputting pulsed laser light with a wavelength of approximately 745.2 nm, a solid-state amplifier, and a wavelength conversion system for wavelength conversion to third harmonic light with a wavelength of approximately 248.4 nm. In this case, the wavelength conversion element may be an LBO crystal for wavelength conversion to second harmonic light and a CLBO crystal for summing the second harmonic light and the fundamental wave.

[0103] 4.2 Example of a semiconductor laser system 4.2.1 Configuration FIG. 10 is a diagram schematically illustrating an example of the configuration of the semiconductor laser system 104. As shown in FIG.

[0104] The semiconductor laser system 104 includes a single-longitudinal-mode distributed feedback (DFB) semiconductor laser 132, a semiconductor laser control processor 134, and an SOA 136. The semiconductor laser 132 includes a semiconductor laser element 138, a Peltier element 148, a temperature sensor 150, a current controller 152, and a temperature controller 154. The semiconductor laser element 138 includes a first cladding layer 140, an active layer 142, and a second cladding layer 144, and includes a grating 146 at the boundary between the active layer 142 and the second cladding layer 144. The semiconductor laser 132 in the first embodiment is an example of a "first semiconductor laser" in the present disclosure.

[0105] 4.2.2 Operation The central oscillation wavelength of the semiconductor laser 132 can be changed by changing the set temperature Ts of the semiconductor laser element 138 and / or the current value I flowing through the semiconductor laser element 138. The solid-state seeder control processor 110 obtains the set temperature Ts and the current value I from the laser control processor 12A and sends them to the semiconductor laser control processor 134. The semiconductor laser control processor 134 controls the temperature controller 154 and the current controller 152, respectively, in accordance with the set temperature Ts and the current value I.

[0106] When changing the oscillation wavelength of the semiconductor laser 132 at high speed, the value of the current I flowing through the semiconductor laser 132 is changed at high speed. This makes it possible to change the wavelength of the CW laser light at high speed.

[0107] The solid-state seeder control processor 110 also receives a trigger signal Tr2 from the laser control processor 12 A. When the trigger signal Tr2 is input to the solid-state seeder 102, a pulse signal is input to the SOA 136.

[0108] By passing a pulse current corresponding to this pulse signal through the semiconductor laser element 138 of the SOA 136, the CW laser light output from the semiconductor laser 132 is pulse-amplified and a pulsed laser light is output.

[0109] 11 is a graph showing the spectrum of the pulsed laser light output from the SOA 136. As shown in FIG. 11, the SOA 136 outputs two pulses of wavelength λ1 S and λ1 L A pulsed laser beam is output.

[0110] 4.2.3 Other The SOA 136 may be configured to amplify a CW signal by passing a direct current through it, in which case the subsequent solid-state amplifier 106 is a pulse amplifier.

[0111] 4.3 Temperature control of semiconductor laser by laser control processor 4.3.1 Flowchart example 1 FIG. 12 is a flowchart showing the processing steps of the semiconductor laser control processor 134 when controlling the temperature of the semiconductor laser 132 based on the target center wavelength λct.

[0112] In step S31, the laser control processor 12A calculates the target center wavelength λct, which is the average value of the target wavelengths. That is, the laser control processor 12A calculates λct=(λ S t+λ L t) / 2.

[0113] In step S32, the laser control processor 12A calls up the relational expression between the set temperature Ts of the semiconductor laser 132 when a reference current value Ics is applied to the semiconductor laser 132 and the wavelength λ after excimer amplification.

[0114] In step S33, the laser control processor 12A calculates the set temperature Ts of the semiconductor laser 132 at the target center wavelength λct from the relational expression called up in step S32.

[0115] In step S34, the laser control processor 12A sets the set temperature of the semiconductor laser 132 to the set temperature Ts calculated in step S33.

[0116] In step S35, the laser control processor 12A determines whether or not to continue temperature control of the semiconductor laser 132. If the temperature control is not to be continued (step S35: No), the laser control processor 12A ends the processing of this flowchart. If the temperature control is to be continued (step S35: Yes), the laser control processor 12A proceeds to step S36.

[0117] In step S36, the laser control processor 12A determines whether or not to change the target center wavelength λct of the semiconductor laser 132. If the target center wavelength λct is not to be changed (step S36: No), the laser control processor 12A returns the process to step S34. If the target center wavelength λct is to be changed (step S36: Yes), the laser control processor 12A returns the process to step S31.

[0118] In this way, the laser control processor 12A controls the temperature of the semiconductor laser 132 based on the relationship between the temperature of the semiconductor laser 132 and the wavelength of the pulsed laser light PL3 ​​so that the average value of the measured wavelength of the pulsed laser light PL3 ​​becomes the target center wavelength λct.

[0119] 13 is a graph showing the relationship between the set temperature Ts of the semiconductor laser 132 and the wavelength λ after excimer amplification for a reference current value Ics. The reference current value Ics is a current value at which the semiconductor laser 132 can oscillate and at which the wavelength and performance of the semiconductor laser 132 can be maintained even if the current is changed within a range that changes the wavelength.

[0120] 13, the horizontal axis represents the wavelength λ after excimer amplification, and the vertical axis represents the set temperature Ts of the semiconductor laser 132. The laser control processor 12A may measure in advance the relationship between the temperature of the semiconductor laser 132 and the wavelength of the pulsed laser light PL3 ​​as the relational expression in step S32, and obtain an approximate straight line or an approximate curve as shown in Fig. 13 from the measured data. Furthermore, table data may be used instead of the approximate straight line or the approximate curve.

[0121] 4.3.2 Flowchart example 2 FIG. 14 is a flowchart showing the processing steps of the laser control processor 12A when controlling the temperature of the semiconductor laser 132 based on the average current value Ic.

[0122] In step S41, the laser control processor 12A calculates the average current value Ic of the semiconductor laser 132. That is, the laser control processor 12A calculates Ic=(I S +I L ) / 2.

[0123] In step S42, the laser control processor 12A calculates the difference ΔIcs between the average current value Ic calculated in step S41 and the reference current value Ics. That is, the laser control processor 12A calculates ΔIcs=Ic−Ics.

[0124] In step S43, the laser control processor 12A determines whether the absolute value of the difference ΔIcs calculated in step S42 is equal to or less than the allowable value ΔIstr. That is, the laser control processor 12A determines whether |ΔIcs|≦ΔIstr is satisfied. If |ΔIcs|≦ΔIstr is satisfied (step S43: Yes), the laser control processor 12A returns the process to step S41. If |ΔIcs|≦ΔIstr is not satisfied (step S43: No), the laser control processor 12A proceeds to step S44.

[0125] In step S44, the laser control processor 12A changes the set temperature Ts of the semiconductor laser 132 so that ΔIcs approaches zero.

[0126] In step S45, the laser control processor 12A determines whether or not to continue temperature control of the semiconductor laser 132. If the temperature control is not to be continued (step S45: No), the laser control processor 12A ends the processing of this flowchart. If the temperature control is to be continued (step S45: Yes), the laser control processor 12A returns the processing to step S41.

[0127] 4.3.3 Actions and Effects When the target center wavelength is changed significantly, there are cases where the wavelength after excimer amplification cannot be controlled by the current value of the semiconductor laser 132 alone.

[0128] 12 or 14, by setting the temperature of the semiconductor laser 132, it is possible to maintain the average current value flowing through the semiconductor laser 132 near the reference current value Ics even when the target center wavelength is significantly changed. Here, the most preferable value of the reference current value Ics is the central value in the variable range of the current flowing through the semiconductor laser 132. The average current value flowing through the semiconductor laser 132 in the first embodiment is an example of the "average current value" in the present disclosure.

[0129] As a result, even if the target wavelength of the two-wavelength spectrum is changed, it is possible to change the wavelength to two wavelengths with high precision for each pulse.

[0130] 4.4 Wavelength conversion system 4.4.1 Configuration FIG. 15 is a diagram schematically illustrating an example of the configuration of the wavelength conversion system 108. As shown in FIG.

[0131] The wavelength conversion system 108 includes a KBBF crystal 162, an LBO crystal 164, rotary stages 166 and 168 as actuators, and a rotary stage driver 170 as a controller for the actuators. "KBBF" is represented by the chemical formula KBe2BO3F2. "LBO" is represented by the chemical formula LiBO5. The KBBF crystal 162 in the first embodiment is an example of the "first nonlinear crystal" in the present disclosure.

[0132] The KBBF crystal 162 is placed on a rotation stage 166. The LBO crystal 164 is placed on a rotation stage 168. Each of the rotation stages 166 and 168 includes a piezoelectric element to rotate the wavelength conversion element at high speed. A rotation stage driver 170 controls the angle of each of the rotation stages 166 and 168.

[0133] The actuator may also be a heater for controlling the temperature of the nonlinear crystal, and the controller may be a temperature controller.

[0134] 4.4.2 Operation The pulsed laser light input to the wavelength conversion system 108 is incident on the LBO crystal 164. The LBO crystal 164 converts the pulsed laser light with a wavelength of approximately 773.6 nm into pulsed laser light with a wavelength of approximately 386.8 nm, which is second harmonic light.

[0135] The KBBF crystal 162 converts the pulsed laser light having a wavelength of approximately 386.8 nm output from the LBO crystal 164 into pulsed laser light having a wavelength of approximately 193.4 nm, which is second harmonic light.

[0136] The pulsed laser light converted to a wavelength of approximately 193.4 nm is output from the wavelength conversion system 108.

[0137] In the case of single-wavelength oscillation, the laser control processor 12A controls the angles of incidence of the KBBF crystal 162 and the LBO crystal 164 so as to maximize the wavelength conversion efficiency at the target wavelength λt, i.e., to achieve phase matching. The angles of incidence of the KBBF crystal 162 and the LBO crystal 164 are controlled by rotating the rotation stages 166 and 168.

[0138] FIG. 16 is a graph showing the relationship between the wavelength λ after wavelength conversion and the wavelength conversion efficiency η. In FIG. 16, the horizontal axis represents the wavelength λ after wavelength conversion, and the vertical axis represents the wavelength conversion efficiency η. FIG. 16 also shows the wavelength conversion efficiency curve WCE(KBBF) of the KBBF crystal 162 and the wavelength conversion efficiency curve WCE(LBO) of the LBO crystal 164. As shown in FIG. 16, the wavelength conversion efficiency of the KBBF crystal 162, which is the downstream nonlinear crystal, decreases when the wavelength λ after wavelength conversion deviates to a certain extent. Therefore, when the target wavelength difference Δλt between the two wavelength spectra is large, the pulse energy of the wavelength-converted light may decrease if the incident angle of the KBBF crystal 162 is not controlled to achieve phase matching for each pulse.

[0139] 4.5 Temperature control system for nonlinear crystals 4.5.1 Configuration 17 is a diagram schematically illustrating an example of the configuration of a nonlinear crystal temperature adjustment system 180. The temperature adjustment system 180 shown in FIG. 17 can be applied to temperature adjustment of the KBBF crystal 162 and the LBO crystal 164 in FIG.

[0140] The nonlinear crystal temperature adjustment system 180 includes a nonlinear crystal 182 , a nonlinear crystal holder 184 , a temperature sensor 186 , a heater 188 , and a temperature controller 190 .

[0141] The nonlinear crystal 182 is fixed to a nonlinear crystal holder 184. The temperature sensor 186 is disposed in the nonlinear crystal holder 184 near the nonlinear crystal 182. The heater 188 is disposed within the nonlinear crystal holder 184.

[0142] Furthermore, a rotation stage 192 for controlling the angle of incidence of the nonlinear crystal 182 and a rotation stage controller 194 for controlling the rotation stage 192 may be additionally provided.

[0143] 4.5.2 Operation The temperature controller 190 receives data on the temperature Tn of the nonlinear crystal 182 from the laser control processor 12A. The temperature controller 190 controls the power of the heater 188 so that the temperature Tn is the received temperature Tn, thereby controlling the temperature of the nonlinear crystal 182 to approach Tn.

[0144] The laser control processor 12A determines and sets the temperature Tn of the nonlinear crystal 182 from the target wavelength λt based on data on the relationship between the wavelength and temperature at which the wavelength conversion efficiency of the nonlinear crystal 182 is maximized. The data may be measured in advance, an approximation curve may be calculated, and stored, or may be stored as table data.

[0145] If phase matching cannot be achieved by temperature control alone, phase matching may be achieved by controlling the angle of incidence with the rotation stage 192 .

[0146] Fig. 18 is data stored in the laser control processor 12A on the relationship between the wavelength and temperature at which the wavelength conversion efficiency of the nonlinear crystal 182 is maximized, and is a graph showing the relationship between the target center wavelength after wavelength conversion and the temperature T at which the wavelength conversion efficiency is maximized. In Fig. 18, the horizontal axis represents the target center wavelength after wavelength conversion, and the vertical axis represents the temperature T at which the wavelength conversion efficiency is maximized. As shown in Fig. 18, when the target center wavelength after wavelength conversion is λct, the temperature at which the wavelength conversion efficiency is maximized is Tn.

[0147] 4.5.3 Other The nonlinear crystal 182 does not need to be placed in a cell if it is a KBBF crystal or an LBO crystal. On the other hand, if the nonlinear crystal 182 is a CLBO crystal, it is hygroscopic, so the nonlinear crystal 182 and the nonlinear crystal holder 184 must be placed in a cell (not shown) and kept at, for example, 120 to 170°C. "CLBO" has the chemical formula CsLiBO 10 It is expressed as:

[0148] 4.6 Wavelength conversion system 4.6.1 Flowchart example FIG. 19 is a flowchart showing the processing procedure of the laser control processor 12A when controlling the wavelength conversion system 108.

[0149] In step S51, the laser control processor 12A reads the target center wavelength λct and the target wavelength difference Δλt of the two-wavelength spectrum calculated from the two-wavelength parameters received from the exposure control processor 310.

[0150] In step S52, the laser control processor 12A determines whether the target wavelength difference Δλt between the two-wavelength spectra acquired in step S51 is within the allowable range Δλtr for a decrease in wavelength conversion efficiency. That is, the laser control processor 12A determines whether Δλt≦Δλtr is satisfied. If Δλt≦Δλtr is satisfied (step S52: Yes), the laser control processor 12A proceeds to step S53. If Δλt≦Δλtr is not satisfied (step S52: No), the laser control processor 12A proceeds to step S56.

[0151] In step S53, the laser control processor 12A controls the angles of incidence of the KBBF crystal 162 and the LBO crystal 164 so that the wavelength at which the wavelength conversion efficiency is maximized becomes the target central wavelength λct obtained in step S51. That is, the laser control processor 12A controls the rotation stages 166 and 168 so that the KBBF crystal 162 and the LBO crystal 164 are phase-matched at the target central wavelength λct.

[0152] In step S54, the laser control processor 12A determines whether or not to continue the two-wavelength control. If the two-wavelength control is to be continued (step S54: Yes), the laser control processor 12A proceeds to step S55. If the two-wavelength control is not to be continued (step S54: No), the laser control processor 12A ends the processing of this flowchart.

[0153] In step S55, the laser control processor 12A determines whether the target center wavelength λct or the target wavelength difference Δλt of the two-wavelength spectrum has changed. If the target center wavelength λct or the target wavelength difference Δλt of the two-wavelength spectrum has not changed (step S55: No), the laser control processor 12A returns the process to step S53. If the target center wavelength λct or the target wavelength difference Δλt of the two-wavelength spectrum has changed (step S55: Yes), the laser control processor 12A returns the process to step S51.

[0154] In step S56, the laser control processor 12A determines that the wavelength at which the wavelength conversion efficiency is maximized is the target short wavelength λ S The incident angles of the KBBF crystal 162 and the LBO crystal 164 are controlled so that t is satisfied.

[0155] In step S57, the laser control processor 12A determines whether or not excimer laser light has been detected by the spectrum monitor 126. If excimer laser light has not been detected (step S57: No), the laser control processor 12A waits until excimer laser light is detected. If excimer laser light has been detected (step S57: Yes), the laser control processor 12A proceeds to step S58.

[0156] In step S58, the laser control processor 12A determines that the wavelength at which the wavelength conversion efficiency is maximized is the target long wavelength λ L The incident angles of the KBBF crystal 162 and the LBO crystal 164 are controlled so that t is satisfied.

[0157] In step S59, the laser control processor 12A determines whether or not excimer laser light has been detected by the spectrum monitor 126. If excimer laser light has not been detected (step S59: No), the laser control processor 12A waits until excimer laser light is detected. If excimer laser light has been detected (step S59: Yes), the laser control processor 12A proceeds to step S60.

[0158] In step S60, the laser control processor 12A determines whether or not to continue the two-wavelength control. If the two-wavelength control is to be continued (step S60: Yes), the laser control processor 12A proceeds to step S61. If the two-wavelength control is not to be continued (step S60: No), the laser control processor 12A ends the processing of this flowchart. In step S61, the laser control processor 12A determines whether the target center wavelength λct or the target wavelength difference Δλt of the two-wavelength spectrum has changed. If the target center wavelength λct or the target wavelength difference Δλt of the two-wavelength spectrum has not changed (step S61: No), the laser control processor 12A returns the process to step S56. If the target center wavelength λct or the target wavelength difference Δλt of the two-wavelength spectrum has changed (step S61: Yes), the laser control processor 12A returns the process to step S51.

[0159] 4.6.2 Operation 19, the target wavelength difference Δλt between the two wavelength spectra is determined to determine whether the decrease in wavelength conversion efficiency is within an allowable range. Δλt is, for example, in the range of 1 pm to 2 pm. Depending on the result of this determination, the control of the incident angles of the wavelength conversion elements, the KBBF crystal 162 and the LBO crystal 164, is switched.

[0160] 20 and 21 are graphs showing the relationship between wavelength λ after excimer amplification and wavelength conversion efficiency, in which the horizontal axis represents wavelength λ after excimer amplification and the vertical axis represents wavelength conversion efficiency.

[0161] As shown in FIG. 20, if the target wavelength difference Δλt of the two-wavelength spectrum is within a range in which the decrease in wavelength conversion efficiency is suppressed, the angles of incidence of the KBBF crystal 162 and the LBO crystal 164 are controlled so that the wavelength conversion efficiency is maximized at the target central wavelength λct of the two-wavelength spectrum.

[0162] On the other hand, as shown in FIG. 21, when the target wavelength difference Δλt between the two wavelength spectra is larger than the range in which the decrease in wavelength conversion efficiency is suppressed, the maximum conversion efficiency is synchronized with the target short wavelength λ for each pulse. S t and target long wavelength λ L At least the incident angle of the KBBF crystal 162, which is the nonlinear crystal arranged at the most downstream side, is controlled so that the angle becomes t.

[0163] If the target wavelength difference Δλt between the two wavelength spectra is larger, the target short wavelength λ S t and target long wavelength λ L The incident angle of the LBO crystal 164, which is the second nonlinear crystal from the downstream side, may also be controlled so that t is obtained.

[0164] 4.6.3 Actions and Effects If the target wavelength difference Δλt is within the allowable range, the change in wavelength conversion efficiency is suppressed, and the pulse energy and the wavelength λ of the spectrum of the two wavelengths are S and λ L This is controlled with high precision for each pulse.

[0165] When the target wavelength difference Δλt≦1 pm to 2 pm, it is possible to form a resist pattern for a contact hole and provide a margin for the process by increasing the depth of focus.

[0166] When the target wavelength difference Δλt is greater than 1 pm to 2 pm, it can also be used to form thick-film resist in the 3D semiconductor manufacturing process.

[0167] 5. Embodiment 2 The case where the target exposure spectrum is multi-wavelength will be explained. Here, wavelength control will be explained when the target wavelength λ(k)t is changed periodically.

[0168] 5.1 Configuration 22 is a diagram showing the configuration of an exposure system according to embodiment 2. The exposure system includes a laser apparatus 100 and an exposure apparatus 300.

[0169] The exposure control processor 310 of the exposure apparatus 300 sends the multi-wavelength exposure target wavelengths λ(1)t, λ(2)t, ..., wavelength λ(n)t to the laser control processor 12A. The laser control processor 12A controls the laser apparatus 100 according to these parameters.

[0170] 5.2 Laser Control Processor Flowchart Wavelength control when the target wavelength λ(k)t is periodically changed will be described. Fig. 23 is a flowchart showing the processing procedure of the laser control processor 12A in embodiment 2. The processing procedure of the laser control processor 12A in embodiment 2 is an example of the "wavelength control method of a laser device" in the present disclosure.

[0171] In step S71, the laser control processor 12A reads target multi-wavelength control parameter data from the exposure control processor 310. The target multi-wavelength control parameter data includes λ(1)t, λ(2)t, . . . , λ(n)t.

[0172] In step S72, the laser control processor 12A sets the current values ​​I(1), I(2), ..., I(n) to be applied to the semiconductor laser 132 at each target wavelength to their respective initial values ​​I0(1), I0(2), ..., I0(n). That is, the laser control processor 12A sets I(1) = I0(1), I(2) = I0(2), ..., I(n) = I0(n).

[0173] In step S73, the laser control processor 12A initializes the variable k to 1. That is, the laser control processor 12A sets k=1.

[0174] In step S74, the laser control processor 12A sets the command current value I of the semiconductor laser 132 to I(k). That is, the laser control processor 12A sets I=I(k).

[0175] In step S75, the laser control processor 12A determines whether or not excimer laser light has been detected by the spectrum monitor 126. If excimer laser light has not been detected (step S75: No), the laser control processor 12A waits until excimer laser light is detected. If excimer laser light has been detected (step S75: Yes), the laser control processor 12A proceeds to step S76.

[0176] In step S76, the laser control processor 12A measures the wavelength λ(k) of the excimer laser light using the spectrum monitor 126.

[0177] In step S77, the laser control processor 12A calculates the difference Δλ(k) between the wavelength λ(k) measured in step S76 and the target wavelength λ(k)t. That is, the laser control processor 12A calculates Δλ(k)=λ(k)-λ(k)t.

[0178] In step S78, the laser control processor 12A calculates the current value I(k)D of the semiconductor laser 132 at which Δλ(k) calculated in step S77 approaches zero.

[0179] In step S79, the laser control processor 12A sets the current value I(k) to be passed through the semiconductor laser 132 to the current value I(k)D calculated in step S78. That is, the laser control processor 12A sets I(k)=I(k)D.

[0180] In step S80, the laser control processor 12A determines whether k=n. If k=n is not true (step S80: No), the laser control processor 12A proceeds to step S81. If k=n is true (step S80: Yes), the laser control processor 12A proceeds to step S82.

[0181] In step S81, the laser control processor 12A increments the variable k. That is, the laser control processor 12A sets k = k + 1. Then, the laser control processor 12A returns the process to step S74. As a result, wavelength control is performed at each target wavelength until k becomes 1 to n.

[0182] In step S82, the laser control processor 12A determines whether or not to continue multi-wavelength control. If multi-wavelength control is to be continued (step S82: Yes), the laser control processor 12A proceeds to step S83. If multi-wavelength control is not to be continued (step S82: No), the laser control processor 12A ends the processing of this flowchart.

[0183] In step S83, the laser control processor 12A determines whether or not to update the multi-wavelength control parameters. If the multi-wavelength control parameters are not to be updated (step S83: No), the laser control processor 12A returns the process to step S73. If the multi-wavelength control parameters are to be updated (step S83: Yes), the laser control processor 12A returns the process to step S71.

[0184] As described above, when the laser device 100 outputs laser light of a target wavelength λ(k)t, it controls the current value I(k) of the semiconductor laser 132 based on the measurement value of the wavelength λ(k) of the laser light output at the most recent target wavelength λ(k)t.

[0185] 5.3 Temperature control of semiconductor laser 5.3.1 Flowchart Example 1 FIG. 24 is a flowchart showing the processing steps of the semiconductor laser control processor 134 when controlling the temperature of the semiconductor laser 132 based on the target center wavelength λct.

[0186] In step S91, the semiconductor laser control processor 134 calculates the target center wavelength λct. That is, the semiconductor laser control processor 134 calculates λct={λ(1)t+λ(2)t+λ(3)t+···+λ(n)t} / n.

[0187] Steps S92 to S96 following step S91 are the same as steps S32 to S36 shown in FIG. 12, respectively.

[0188] 5.3.2 Flowchart example 2 FIG. 25 is a flowchart showing the processing procedure of the semiconductor laser control processor 134 when controlling the temperature of the semiconductor laser 132 based on the average current value Ic.

[0189] In step S101, the laser control processor 12A calculates the average current value Ic of the semiconductor laser 132. That is, the laser control processor 12A calculates I C Calculate ={I(1)+I(2)+···+I(n)} / n.

[0190] Steps S102 to S105 following step S101 are the same as steps S42 to S45 shown in FIG. 14, respectively.

[0191] 5.3.3 Actions and Effects When the target center wavelength is changed significantly, it may not be possible to control the wavelength after excimer amplification using only the current value of the semiconductor laser.

[0192] By setting the temperature of the semiconductor laser 132 as shown in Figures 24 and 25, it is possible to maintain the average current value flowing through the semiconductor laser 132 near the reference current value Ics even if the target center wavelength is changed significantly.

[0193] As a result, even when the target wavelength of the multi-wavelength spectrum is changed, it is possible to change the wavelength to multiple wavelengths with high precision for each pulse.

[0194] 5.4 Wavelength conversion system 5.4.1 Flowchart example FIG. 26 is a flowchart showing the processing steps of the laser control processor 12A when controlling the wavelength conversion system 108.

[0195] In step S111, the laser control processor 12A calculates the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum.

[0196] In step S112, the laser control processor 12A determines whether the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum is within the allowable range Δλtr for a decrease in wavelength conversion efficiency. That is, the laser control processor 12A determines whether Δλmaxt≦Δλtr is satisfied. If Δλmaxt≦Δλtr is satisfied (step S112: Yes), the laser control processor 12A proceeds to step S113. If Δλmaxt≦Δλtr is not satisfied (step S112: No), the laser control processor 12A proceeds to step S116.

[0197] In step S113, the laser control processor 12A controls the angles of incidence of the KBBF crystal 162 and the LBO crystal 164 so that the wavelength at which the wavelength conversion efficiency is maximized becomes the target central wavelength λct. That is, the laser control processor 12A controls the rotation stages 166 and 168 so that the KBBF crystal 162 and the LBO crystal 164 are phase-matched at the target central wavelength λct.

[0198] In step S114, the laser control processor 12A determines whether or not to continue the multi-wavelength control. If the multi-wavelength control is to be continued (step S114: Yes), the laser control processor 12A proceeds to step S115. If the multi-wavelength control is not to be continued (step S114: No), the laser control processor 12A ends the processing of this flowchart.

[0199] In step S115, the laser control processor 12A determines whether the target center wavelength λct or the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum has changed. If the target center wavelength λct or the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum has not changed (step S115: No), the laser control processor 12A returns the process to step S113. If the target center wavelength λct or the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum has changed (step S115: Yes), the laser control processor 12A returns the process to step S111.

[0200] In step S116, the laser control processor 12A initializes the variable k to 1. That is, the laser control processor 12A sets k=1.

[0201] In step S117, the laser control processor 12A controls the angles of incidence of the KBBF crystal 162 and the LBO crystal 164 so that the wavelength at which the wavelength conversion efficiency is maximized becomes the target wavelength λ(k)t.

[0202] In step S118, the laser control processor 12A determines whether or not excimer laser light has been detected by the spectrum monitor 126. If excimer laser light has not been detected (step S118: No), the laser control processor 12A waits until excimer laser light is detected. If excimer laser light has been detected (step S118: Yes), the laser control processor 12A proceeds to step S119.

[0203] In step S119, the laser control processor 12A determines whether k=n. If k=n is not true (step S119: No), the laser control processor 12A proceeds to step S120. If k=n is true (step S119: Yes), the laser control processor 12A proceeds to step S121.

[0204] In step S120, the laser control processor 12A increments the variable k. That is, the laser control processor 12A sets k = k + 1. Then, the laser control processor 12A returns the process to step S117. As a result, the incident angle of the nonlinear crystal for each target wavelength is controlled until k becomes 1 to n.

[0205] In step S121, the laser control processor 12A determines whether or not to continue multi-wavelength control. If multi-wavelength control is to be continued (step S121: Yes), the laser control processor 12A proceeds to step S122. If multi-wavelength control is not to be continued (step S121: No), the laser control processor 12A ends the processing of this flowchart.

[0206] In step S122, the laser control processor 12A determines whether the target center wavelength λct or the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum has changed. If the target center wavelength λct or the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum has not changed (step S112: No), the laser control processor 12A returns the process to step S116. If the target center wavelength λct or the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum has changed (step S112: Yes), the laser control processor 12A returns the process to step S111.

[0207] 27 and 28 are graphs showing the relationship between wavelength λ after excimer amplification and wavelength conversion efficiency, in which the horizontal axis represents wavelength λ after excimer amplification and the vertical axis represents wavelength conversion efficiency.

[0208] As shown in Figure 27, if the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum is within a range in which a decrease in wavelength conversion efficiency is suppressed, the incident angles of the KBBF crystal 162 and the LBO crystal 164 are controlled so that the wavelength conversion efficiency is maximized at the target center wavelength λct of the multi-wavelength spectrum.

[0209] On the other hand, as shown in FIG. 28, when the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum is larger than the range in which the decrease in wavelength conversion efficiency is suppressed, at least the incident angle of the KBBF crystal 162, which is a nonlinear crystal arranged at the most downstream side, is controlled so that the maximum conversion efficiency is synchronized with each target wavelength λ(k)t for each pulse.

[0210] If the maximum target wavelength difference Δλmaxt of the multi-wavelength spectrum is even larger, the incident angle of the LBO crystal 164, which is the second nonlinear crystal arranged downstream, may also be controlled so that the maximum conversion efficiency is at each target wavelength λ(k)t.

[0211] 5.4.2 Flowchart example FIG. 29 is a flowchart showing the processing procedure of step S111 in FIG.

[0212] In step S131, the laser control processor 12A reads each target wavelength from the exposure control processor 310. That is, the laser control processor 12A reads λ(1)t, λ(2)t, . . . , λ(n)t.

[0213] In step S132, the laser control processor 12A extracts the shortest target wavelength λmint and the longest target wavelength λmaxt from among the target wavelengths.

[0214] In step S133, the laser control processor 12A calculates the difference Δλmaxt between the longest target wavelength λmaxt and the shortest target wavelength λmint. That is, the laser control processor 12A calculates Δλmaxt=λmaxt−λmint.

[0215] Thereafter, the laser control processor 12A ends the processing of this flowchart, and proceeds to step S112 in FIG.

[0216] 6. Embodiment 3 6.1 Dual wavelength exposure 6.1.1 Flowchart example FIG. 30 is a flowchart showing the processing procedure of the laser control processor 12A in the case of dual wavelength exposure in the third embodiment.

[0217] Steps S141 to S145 are the same as steps S11 to S15 shown in Fig. 7. The processes of steps S143 to S145 are wavelength measurement and control processes for short wavelengths.

[0218] Steps S146 to S148 are the same as steps S19 to S21 shown in Fig. 7. The processes of steps S146 to S148 are wavelength measurement and control processes for long wavelengths.

[0219] In step S149, the laser control processor 12A selects the shorter wavelength λ S and long wavelength λ LThe measured value and the set current value I S and I L From this, the target short wavelength λ S t and target long wavelength λ L The current values ​​I approaching t S D and I L Calculate D.

[0220] In step S150, the laser control processor 12A determines the set current value I for the short wavelength to be applied to the semiconductor laser 132. S and the set current value I for long wavelengths L The current value I calculated in step S149 S D and I L D. That is, the laser control processor 12A sets I S =I S D.I. L =I L Let's call it D.

[0221] In this way, the laser control processor 12A controls the target short wavelength λ S When outputting pulsed laser light of t, the nearest target short wavelength λ S Wavelength λ of the pulsed laser light emitted at t S Measured values ​​of λ and different target long wavelengths λ L Wavelength λ of the pulsed laser light emitted at t L The current value I of the semiconductor laser 132 is S The laser control processor 12A also controls the target long wavelength λ L When outputting pulsed laser light of t, the nearest same target long wavelength λ L Wavelength λ of the pulsed laser light emitted at t L Measured values ​​of λ and different target short wavelengths λ S Wavelength λ of the pulsed laser light emitted at t S The current value I of the semiconductor laser 132 is L Control.

[0222] In step S151, the laser control processor 12A determines whether or not to continue the two-wavelength control. If the two-wavelength control is to be continued (step S151: Yes), the laser control processor 12A proceeds to step S152. If the two-wavelength control is not to be continued (step S151: No), the laser control processor 12A ends the processing of this flowchart.

[0223] In step S152, the laser control processor 12A determines whether or not to update the dual-wavelength control parameter. If the dual-wavelength control parameter is not to be updated (step S152: No), the laser control processor 12A returns the process to step S143. If the dual-wavelength control parameter is to be updated (step S152: Yes), the laser control processor 12A returns the process to step S141.

[0224] 6.1.2 Flowchart example FIG. 31 is a flowchart showing the processing procedure of step S149 in FIG.

[0225] In step S161, the laser control processor 12A selects the short wavelength λ S and long wavelength λ L The measured value and the set current value I S and I L Load.

[0226] In step S162, the laser control processor 12A calculates the laser beam intensity at the point (λ S ,I S ) and point (λ L ,I L ) and calculates the equation of the line that passes through these two points. That is, the laser control processor 12A calculates I=a·λ+b, where the slope a and the intercept b are constants.

[0227] The relationship between the oscillation wavelength λ of the semiconductor laser 132 and the current value I can be approximated by a straight line. L -I S ) / (λ L -λ S ), intercept b=I S -a λS It can be calculated by:

[0228] In step S163, the laser control processor 12A calculates the target short wavelength λ from the equation of the straight line obtained in S162. S Current value I S That is, the laser control processor 12A calculates I S D=a λ S Find t+b.

[0229] In step S164, the laser control processor 12A calculates the target long wavelength λ from the equation of the straight line obtained in S162. L Current value I L That is, the laser control processor 12A calculates I L D=a λ L Find t+b.

[0230] Thereafter, the laser control processor 12A ends the processing of this flowchart, and proceeds to step S150 in FIG.

[0231] FIG. 32 is a graph showing the relationship between the wavelength λ after excimer amplification and the current value I of the semiconductor laser 132. In FIG. 32, the horizontal axis represents the wavelength λ after excimer amplification, and the vertical axis represents the current value I of the semiconductor laser. In FIG. 32, S ,I S ) and point (λ L ,I L ) and the line I=a·λ+b passing through the two points. From this line I=a·λ+b, the target short wavelength λ S Current value I S D and target long wavelength λ L Current value I L D can be found.

[0232] In this way, the laser control processor 12A controls the target short wavelength λ S Wavelength λ of the pulsed laser light emitted at t S Measured value of and target long wavelength λ L Wavelength λ of the pulsed laser light emitted at t LFrom the measured values, an approximate straight line of the relationship between the current for changing the wavelength of the semiconductor laser 132 and the wavelength of the pulsed laser light is obtained, and the current value I of the semiconductor laser 132 is calculated based on the approximate straight line. S and I L Control.

[0233] 6.2 Multi-wavelength exposure 6.2.1 Flowchart example FIG. 33 is a flowchart showing the processing procedure of the laser control processor 12A in the case of multi-wavelength exposure in the third embodiment.

[0234] Steps S171 to S176 are the same as steps S71 to S76 shown in FIG. 23, respectively.

[0235] In step S177, the laser control processor 12A determines whether k=n. If k=n is not true (step S177: No), the laser control processor 12A proceeds to step S178. If k=n is true (step S177: Yes), the laser control processor 12A proceeds to step S179.

[0236] In step S178, the laser control processor 12A increments the variable k. That is, the laser control processor 12A sets k=k+1. Thereafter, the laser control processor 12A returns the process to step S174. The processes of steps S174 to S178 are wavelength measurement and control processes for each target wavelength.

[0237] In step S179, the laser control processor 12A calculates the current values ​​I(1)D, I(2)D, ..., I(n)D that approach the target wavelengths λ(1)t, λ(2)t, ..., λ(n)t, respectively, from the measured values ​​of the multiple wavelengths λ(1), λ(2), ..., λ(n) and the respective set current values ​​I(1), I(2), ..., I(n).

[0238] In step S180, the laser control processor 12A sets the current values ​​to be passed through the semiconductor laser at each target wavelength to the current values ​​I(1)D, I(2)D, . . ., I(n)D calculated in step S179. That is, the laser control processor 12A sets I(1)=I(1)D, I(2)=I(2)D, . . ., I(n)=I(n)D.

[0239] In step S181, the laser control processor 12A determines whether or not to continue multi-wavelength control. If multi-wavelength control is to be continued (step S181: Yes), the laser control processor 12A proceeds to step S182. If multi-wavelength control is not to be continued (step S181: No), the laser control processor 12A ends the processing of this flowchart.

[0240] In step S182, the laser control processor 12A determines whether or not to update the multi-wavelength control parameters. If the multi-wavelength control parameters are not to be updated (step S182: No), the laser control processor 12A returns the process to step S173. If the multi-wavelength control parameters are to be updated (step S182: Yes), the laser control processor 12A returns the process to step S171.

[0241] 6.2.2 Flowchart example FIG. 34 is a flowchart showing the processing procedure of step S179 in FIG.

[0242] In step S191, the laser control processor 12A reads the measured values ​​of multiple wavelengths λ(1), λ(2), . . . , λ(n) and the respective set current values ​​I(1), I(2), . . . , I(n).

[0243] In step S192, the laser control processor 12A obtains an equation for an approximate straight line by the least squares method from n points (λ(1), I(1)), (λ(2), I(2)), ..., (λ(n), I(n)). That is, the laser control processor 12A obtains I=a λ+b, with the slope a and intercept b as constants. The relationship between the oscillation wavelength λ of the semiconductor laser 132 and the current value I can be approximated by a straight line.

[0244] In step S193, the laser control processor 12A initializes the variable k to 1. That is, the laser control processor 12A sets k=1.

[0245] In step S194, the laser control processor 12A calculates the current value I(k)D that results in the target wavelength λ(k)t based on the equation of the straight line calculated in step S192. That is, the laser control processor 12A calculates I(k)D=a·λ(k)t+b.

[0246] In step S195, the laser control processor 12A determines whether k=n. If k=n is not true (step S195: No), the laser control processor 12A proceeds to step S196. If k=n is true (step S195: Yes), the laser control processor 12A ends the processing of this flowchart and proceeds to step S180 in FIG. 33.

[0247] In step S196, the laser control processor 12A increments the variable k. That is, the laser control processor 12A sets k = k + 1. The laser control processor 12A then returns the process to step S194. As a result, the current value for each target wavelength is found until k becomes 1 to n.

[0248] In this way, when outputting pulsed laser light of a target wavelength λ(k)t, the laser control processor 12A controls the current value of the semiconductor laser 132 based on the measurement value of the wavelength λ(k) of the pulsed laser light output at the same target wavelength λ(k)t most recently, and the measurement value of the wavelength of the pulsed laser light output at a target wavelength other than the target wavelength λ(k)t.

[0249] In addition, the laser control processor 12A calculates an approximate straight line of the relationship between the current for changing the wavelength of the semiconductor laser 132 and the wavelength of the pulsed laser light from the measured values ​​of the wavelengths λ(1), λ(2), ..., λ(n) of the pulsed laser light output at the target wavelengths λ(1)t, λ(2)t, ..., λ(n)t, respectively, and controls the current value of the semiconductor laser 132 based on the approximate straight line.

[0250] 7. Embodiment 4 7.1 Configuration 35 is a diagram schematically showing a modified example of the configuration of a solid seeder 200. The solid seeder 200 shown in FIG. 35 can be applied to the solid seeder 102 in FIG.

[0251] The solid-state seeder 200 includes a first solid-state laser device 202 , a second solid-state laser device 208 , a dichroic mirror 220 , a wavelength conversion system 222 , and a solid-state seeder control processor 232 .

[0252] The solid-state seeder 200 is a system configuration in which pulsed laser light PL1 having a wavelength of approximately 1554 nm output from a first solid-state laser device 202 and pulsed laser light PL4 having a wavelength of approximately 257.6 nm output from a second solid-state laser device 208 are converted into pulsed laser light having a wavelength of approximately 193.4 nm by twice adding frequencies in a wavelength conversion system 222.

[0253] The first solid-state laser device 202 includes a first semiconductor laser system 204 and a first solid-state amplifier 206. In Fig. 35, notations with numbers such as "semiconductor laser system 1" and "solid-state amplifier 1" respectively represent the first semiconductor laser system and the first solid-state amplifier.

[0254] 10, the first semiconductor laser system 204 can be configured similarly to the semiconductor laser system 104 shown in FIG. 10, but has a different oscillation wavelength from that of the semiconductor laser system 104. The first semiconductor laser system 204 includes a semiconductor laser 132 that oscillates in a single longitudinal mode CW at a wavelength of approximately 1554 nm, and an SOA 136.

[0255] The first solid-state amplifier 206 is an optical parametric amplifier (OPA), which may be, for example, a periodically poled lithium niobate (PPLN) crystal or a periodically poled potassium titanyl phosphate (PPKTP) crystal.

[0256] The first solid-state amplifier 206 is configured to pulse amplify the seed light by inputting a 1030 nm pulsed laser light, which will be described later, as pump light and a laser light output from the first semiconductor laser system 204 as seed light.

[0257] The second solid-state laser device 208 includes a second semiconductor laser system 210, a second solid-state amplifier 212, two nonlinear crystals, an LBO crystal 214 and a first CLBO crystal 216, which perform wavelength conversion to fourth harmonic light, and a dichroic mirror 218. The fourth harmonic light in the fourth embodiment is an example of the "second harmonic light" in the present disclosure. The LBO crystal 214 and the first CLBO crystal 216 in the fourth embodiment are an example of the "second nonlinear crystal" in the present disclosure.

[0258] The second semiconductor laser system 210 can have a configuration similar to that of the semiconductor laser system 104 shown in FIG. 10 , but has a different oscillation wavelength from that of the semiconductor laser system 104. For example, the second semiconductor laser system 210 includes a semiconductor laser 132 that oscillates in a single longitudinal mode at a wavelength of approximately 1030 nm, and an SOA 136 that pulses and amplifies the laser light output from the semiconductor laser 132. The continuous wave laser light with a wavelength of 1030 nm in the fourth embodiment is an example of a "second laser light" in the present disclosure. The semiconductor laser 132 in the fourth embodiment is an example of a "second semiconductor laser" in the present disclosure. The SOA 136 in the fourth embodiment is an example of a "second amplifier" in the present disclosure.

[0259] The second solid state amplifier 212 includes a Yb fiber amplifier and a Yb:YAG crystal.

[0260] The dichroic mirror 218 is disposed on the optical path between the LBO crystal 214 and the first CLBO crystal 216, and has high transmittance for pulsed laser light with a wavelength of approximately 515 nm and high reflectance for pulsed laser light with a wavelength of approximately 1030 nm. The dichroic mirror 218 is disposed so that the highly reflected pulsed laser light with a wavelength of approximately 1030 nm enters the first solid-state amplifier 206 as pump light.

[0261] The wavelength conversion system 222 includes a second CLBO crystal 224, a third CLBO crystal 226, and rotation stages 228 and 230. The second CLBO crystal 224 and the third CLBO crystal 226 are placed on rotation stages 228 and 230, which include piezoelectric elements, respectively, and are configured so that the incident angle of each crystal can be changed at high speed.

[0262] The dichroic mirror 220 is configured to highly reflect the pulsed laser light having a wavelength of approximately 1554 nm output from the first solid-state laser device 202 and to highly transmit the pulsed laser light having a wavelength of approximately 257.6 nm output from the second solid-state laser device 208, and is positioned so that both pulsed laser lights enter the wavelength conversion system 222 coaxially.

[0263] 7.2 Operation The laser control processor 12A fixes the oscillation wavelength of the second solid-state laser device 208 to 1030 nm. That is, the laser control processor 12A causes the semiconductor laser of the second semiconductor laser system 210 to oscillate at a constant current value.

[0264] Furthermore, in response to the trigger signal Tr2, the laser control processor 12A causes the SOA 136 and the second solid-state amplifier 212 to pulse-amplify the CW laser light. The second solid-state amplifier 212 outputs pulsed laser light PL5 having a wavelength of 1030 nm. The pulsed laser light PL5 in the fourth embodiment is an example of the "fifth pulsed laser light" in the present disclosure.

[0265] The pulsed laser light PL5 output from the second solid-state amplifier 212 is converted into second harmonic light having a wavelength of 515 nm by the LBO crystal 214. The second harmonic light having a wavelength of 515 nm is highly transmitted through the dichroic mirror 218 and converted into pulsed laser light PL4 having a wavelength of 257.6 nm by the first CLBO crystal 216. The second solid-state laser device 208 in the fourth embodiment is an example of the "solid-state laser device" in the present disclosure. The pulsed laser light PL4 in the fourth embodiment is an example of the "fourth pulsed laser light" in the present disclosure.

[0266] Here, the dichroic mirror 218 highly reflects the 1030 nm pulsed laser light that could not be wavelength converted by the LBO crystal 214 and makes it incident as pump light for the first solid-state amplifier 206 of the first solid-state laser device 202 .

[0267] In response to this, the laser control processor 12A controls the current value of the semiconductor laser 132 in the first semiconductor laser system 204 to alternately change the wavelength of the pulsed laser light PL1 output from the first solid-state laser device 202 for each pulse around 1554 nm.

[0268] The pulsed laser light PL1 having a wavelength of approximately 1554 nm output from the first solid-state laser device 202 and the pulsed laser light PL4 having a wavelength of 257.6 nm output from the first CLBO crystal 216 are sum-frequency converted by the second CLBO crystal 224 to a pulsed laser light having a wavelength of approximately 220.9 nm. Furthermore, the pulsed laser light having a wavelength of approximately 220.9 nm and the pulsed laser light having a wavelength of 1554 nm are sum-frequency converted by the third CLBO crystal 226 to a pulsed laser light PL2 having a wavelength of approximately 193.4 nm. The wavelength is then alternately changed to λ for each pulse. S and λ L The pulsed laser beam PL2 is outputted.

[0269] The laser control processor 12A performs control as shown in the flowchart of FIG. 7 to obtain the target two-wavelength spectrum λ S t and λ L The wavelength is controlled alternately for each pulse so as to approach t.

[0270] 7.3 Other In a system using the solid seeder 200, by performing control as shown in the flowchart of the second embodiment, it is also possible to control the wavelength for each pulse so as to approach the target multi-wavelength spectrum.

[0271] In a system using the solid seeder 200, by performing control as shown in the flowchart of the third embodiment, it is also possible to control the wavelength for each pulse so as to approach the target two-wavelength or multi-wavelength spectrum.

[0272] 8. Embodiment 5 8.1 Configuration Fig. 36 is a diagram schematically illustrating a configuration example of a semiconductor laser system 240. The semiconductor laser system 240 shown in Fig. 36 can be applied to the semiconductor laser system 104 in Fig. 6, the first semiconductor laser system 204 in Fig. 35, or the second semiconductor laser system 210 in Fig. 35.

[0273] The semiconductor laser system 240 includes a single-longitudinal-mode distributed Bragg reflector (DBR) semiconductor laser 242 and the SOA 136. The semiconductor laser 242 includes a semiconductor laser element 244. The semiconductor laser 242 in the fifth embodiment is an example of the "first semiconductor laser" in the present disclosure.

[0274] The semiconductor laser element 244 includes a feedback layer 246, an active layer 248, and a phase adjustment region 250 between the first cladding layer 140 and the second cladding layer 144. The feedback layer 246 includes a grating 146 at the boundary between the feedback layer 246 and the second cladding layer 144. The phase adjustment region 250 is disposed between the feedback layer 246 and the active layer 248.

[0275] The semiconductor laser element 244 has electrodes 252, 254, and 256 disposed on the first cladding layer 140. The electrodes 252, 254, and 256 are provided corresponding to the feedback layer 246, the active layer 248, and the phase adjustment region 250, respectively. The other configuration is the same as in Fig. 10. However, current controller 152 is connected to electrodes 252, 254, and 256 by wiring, and is configured so as to be able to independently control the value of the current flowing through each wiring.

[0276] 8.2 Operation The central oscillation wavelength of the semiconductor laser 242 can be changed by changing the set temperature Ts of the semiconductor laser element 244 and / or the current value Itu1 or Itu2 flowing through the semiconductor laser element 244. The solid-state seeder control processor 110 acquires the set temperature Ts, the current value Itu1, the current value Itu2, and the current value Iemit from the laser control processor 12A and sends them to the semiconductor laser control processor 134. The semiconductor laser control processor 134 controls the temperature controller 154 in accordance with the set temperature Ts, and controls the current controller 152 in accordance with the current value Itu1, the current value Itu2, and the current value Iemit.

[0277] When the oscillation wavelength of the semiconductor laser 242 is changed at high speed within a fine adjustment range, the current value Itu2 flowing through the phase adjustment region 250 is changed at high speed, whereby the wavelength of the CW laser light can be changed at high speed.

[0278] When changing the oscillation wavelength of the semiconductor laser 242 at high speed and over a wide range, the wavelength of the CW laser light can be changed at high speed by quickly changing the current value Itu1 flowing through the grating 146. However, since there are wavelengths that cannot be oscillated, the current value Itu2 to the phase adjustment region 250 may also be used in combination.

[0279] To oscillate the semiconductor laser 242 and obtain a desired power, a current value Iemit flowing through the active layer 248 is input.

[0280] The solid-state seeder control processor 110 also receives a trigger signal Tr2 from the laser control processor 12 A. When the trigger signal Tr2 is input to the solid-state seeder 200, a pulse signal is input to the SOA 136.

[0281] When the trigger signal Tr2 is input to the solid state seeder 200, a pulse signal is input to the SOA 136.

[0282] By passing a pulse current corresponding to this pulse signal through the semiconductor of the SOA 136, the CW laser light output from the semiconductor laser element 244 is pulse-amplified and a pulsed laser light is output.

[0283] 8.3 Other The SOA 136 may also perform CW amplification by passing a direct current through it, in which case the subsequent solid-state amplifier 106, the first solid-state amplifier 206, or the second solid-state amplifier 212 is an amplifier that performs pulse amplification.

[0284] 8.4 Actions and Effects 10, the current value I, which is a parameter for adjusting wavelength tunability and output power, is common, so changing the wavelength also changes the output power. In contrast, the parameter that mainly determines the output power of the semiconductor laser 242 is Iemit flowing in the active layer, so the output power fluctuation is small even when the current value Itu1 or Itu2 is changed.

[0285] The wavelength tunability of the semiconductor laser 242 and the semiconductor laser 132 is caused by a change in the refractive index in response to a change in the carrier density in the laser waveguide, so that the carrier density is substantially fixed at the oscillation threshold carrier density above the laser oscillation threshold current in the semiconductor laser 132. Therefore, the amount of wavelength tunability is relatively small even if the injection current is increased or decreased above the laser oscillation threshold current.

[0286] In contrast, in the semiconductor laser 242, the carrier density of the active layer 248 is almost fixed at the oscillation threshold carrier density at a laser oscillation threshold current or higher, as in the semiconductor laser 132, but the portion of the grating 146 and the phase adjustment region 250 do not have laser gain, so the carrier density can change significantly depending on the injected current. Therefore, the semiconductor laser 242 has a larger wavelength tunability than the semiconductor laser 132.

[0287] 9. Embodiment 6 9.1 Configuration Fig. 37 is a diagram schematically illustrating a configuration example of a semiconductor laser system 260. The semiconductor laser system 260 shown in Fig. 37 can be applied to the semiconductor laser system 104 in Fig. 6, the first semiconductor laser system 204 in Fig. 35, or the second semiconductor laser system 210 in Fig. 35.

[0288] The semiconductor laser system 260 includes a single-longitudinal-mode sampled grating distributed Bragg reflector (SG-DBR) semiconductor laser 262. The semiconductor laser 262 includes a semiconductor laser element 264. The semiconductor laser 262 in the sixth embodiment is an example of the "first semiconductor laser" in the present disclosure.

[0289] The semiconductor laser element 264 includes an active layer 248 , a phase adjustment region 250 , a first feedback layer 266 , and a second feedback layer 268 between the first cladding layer 140 and the second cladding layer 144 .

[0290] The first feedback layer 266 includes a first grating 146a at the interface between the first feedback layer 266 and the second cladding layer 144. The second feedback layer 268 includes a second grating 146b at the interface between the second feedback layer 268 and the second cladding layer 144. The active layer 248 and the phase adjustment region 250 are disposed between the first feedback layer 266 and the second feedback layer 268.

[0291] In the semiconductor laser element 264, electrodes 254, 256, 270, and 272 are disposed on the first cladding layer 140. The electrodes 254, 256, 270, and 272 are provided corresponding to the active layer 248, the phase adjustment region 250, the first feedback layer 266, and the second feedback layer 268, respectively. The other configuration is the same as in Fig. 10. However, current controller 152 is connected to electrodes 254, 256, 270, and 272 by wiring, and is configured so as to be able to independently control the value of the current flowing through each wiring.

[0292] 9.2 Operation The central oscillation wavelength of the semiconductor laser 262 can be changed by changing the set temperature Ts of the semiconductor laser element 264, and / or the value of the current Itu1 or Itu2 flowing through the semiconductor laser element 264, and / or the value of the current Itu3 flowing through the semiconductor laser element 264. The solid-state seeder control processor 110 obtains the current value Itu3 from the laser control processor 12A and transmits it to the semiconductor laser control processor 134. The semiconductor laser control processor 134 controls the current controller 152 in accordance with the current value Itu3.

[0293] When the oscillation wavelength of the semiconductor laser 262 is changed at high speed within a fine adjustment range, the current value Itu2 flowing through the phase adjustment region 250 is changed at high speed, whereby the wavelength of the CW laser light can be changed at high speed.

[0294] When the oscillation wavelength of the semiconductor laser 262 is to be changed quickly and over a wide range, the wavelength of the CW laser light can be changed quickly by quickly changing the current value Itu1 flowing through the first grating 146a and the current value Itu3 flowing through the second grating 146b. However, since there are wavelengths that cannot be oscillated, the current value Itu2 to the phase adjustment region 250 may also be used.

[0295] To oscillate the semiconductor laser 262 and obtain a desired power, a current value Iemit flowing through the active layer 248 is input.

[0296] When the trigger signal Tr2 is input to the solid state seeder 200, a pulse signal is input to the SOA 136.

[0297] By passing a pulse current corresponding to this pulse signal through the semiconductor of the SOA 136, the CW laser light output from the semiconductor laser element 264 is pulse-amplified and a pulse laser light is output.

[0298] 9.3 Actions and Effects The semiconductor laser 262 has a feature that the output power fluctuates little even when the current value Itu1, Itu2, or Itu3 is changed, since the parameter that mainly determines the output power is Iemit that flows in the active layer.

[0299] In the semiconductor laser 262, the corrugation periods of the first grating 146a and the second grating 146b are slightly different, so that the wavelength tunable range is much larger than that of the semiconductor laser 242, and some can be tuned by 100 nm or more.

[0300] 10. Electronic device manufacturing method FIG. 38 is a schematic diagram illustrating an exemplary configuration of an exposure apparatus 320. In FIG. 38, the exposure apparatus 320 includes an illumination optical system 324 and a projection optical system 325. The illumination optical system 324 illuminates a reticle pattern on a reticle stage RT with laser light incident from the laser apparatus 100. The projection optical system 325 reduces and projects the laser light that has passed through the reticle, forming an image on a workpiece (not shown) placed on a workpiece table WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist. The exposure apparatus 320 exposes the workpiece with laser light reflecting the reticle pattern by synchronously translating the reticle stage RT and the workpiece table WT in opposite directions. After transferring a device pattern to a semiconductor wafer through the exposure process described above, a semiconductor device can be manufactured through multiple processes. A semiconductor device is an example of an “electronic device” in this disclosure.

[0301] 11.Other The above description is intended to be illustrative rather than limiting. Thus, it will be apparent to one skilled in the art that modifications can be made to the disclosed embodiments without departing from the scope of the claims. It will also be apparent to one skilled in the art that the disclosed embodiments can be used in combination.

[0302] Terms used throughout this specification and claims should be construed as "open ended" unless expressly stated otherwise. For example, words such as "comprise," "have," "comprise," and "equip" should be construed as meaning "without excluding the presence of elements other than those listed." In addition, the modifier "a" should be construed as meaning "at least one" or "one or more." In addition, the term "at least one of A, B, and C" should be construed as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C." Furthermore, it should be construed to include combinations of these with elements other than "A," "B," and "C."

Claims

1. a first wavelength-tunable semiconductor laser that outputs a first continuous wave laser beam; a first amplifier that pulses and amplifies the first laser beam and outputs a first pulsed laser beam; a wavelength conversion system that outputs a second pulsed laser beam by wavelength conversion using the first pulsed laser beam; an excimer amplifier that amplifies the second pulsed laser beam and outputs a third pulsed laser beam; a monitor module that measures the wavelength of the third pulsed laser beam; a processor that periodically changes a target wavelength of the third pulse laser beam, and controls a current for changing the wavelength of the first semiconductor laser based on a measurement value of the wavelength of the third pulse laser beam output at the same target wavelength so that the wavelength of the third pulse laser beam becomes the target wavelength; A laser device comprising:

2. 2. The laser device according to claim 1, the processor controls a current for changing the wavelength of the first semiconductor laser, including a measurement value of the wavelength of the third pulse laser beam output at the different target wavelength, so that the wavelength of the third pulse laser beam becomes the target wavelength. Laser device.

3. 3. The laser device according to claim 2, the processor determines an approximate straight line of a relationship between a current for changing the wavelength of the first semiconductor laser and the wavelength of the third pulse laser beam from a measurement value of the wavelength of the third pulse laser beam output at the same target wavelength and a measurement value of the wavelength of the third pulse laser beam output at a different target wavelength, and controls the current for changing the wavelength of the first semiconductor laser based on the approximate straight line. Laser device.

4. 2. The laser device according to claim 1, the processor controls the temperature of the first semiconductor laser so that an average value of a current for changing the wavelength of the first semiconductor laser becomes a reference current value; Laser device.

5. 2. The laser device according to claim 1, The target wavelengths are two wavelengths. Laser device.

6. 2. The laser device according to claim 1, the processor calculates a target center wavelength that is an average value of the periodically changing target wavelengths; controlling the temperature of the first semiconductor laser based on the target center wavelength; Laser device.

7. 7. The laser device according to claim 6, the processor controls the temperature of the first semiconductor laser based on a relationship between the temperature of the first semiconductor laser and the wavelength of the third pulsed laser beam so that an average value of measured values ​​of the wavelength of the third pulsed laser beam becomes the target center wavelength. Laser device.

8. 8. The laser device according to claim 7, the processor measures in advance a relationship between the temperature of the first semiconductor laser and the wavelength of the third pulsed laser beam and approximates the relationship with a straight line or a curve. Laser device.

9. 2. The laser device according to claim 1, the wavelength conversion system includes a first nonlinear crystal; The processor: Calculating a target center wavelength that is an average value of the periodically changing target wavelengths; controlling an actuator so that the first nonlinear crystal is phase-matched at the target center wavelength; Laser device.

10. 10. The laser device according to claim 9, the actuator is a rotation stage; the processor controls an incident angle of the first pulsed laser light to the first nonlinear crystal. Laser device.

11. 10. The laser device according to claim 9, the actuator is a heater; the processor controls the temperature of the first nonlinear crystal. Laser device.

12. 2. The laser device according to claim 1, The wavelength conversion system includes: a first nonlinear crystal; a rotation stage for rotating the nonlinear crystal; Including, the processor controls the rotation stage so that the wavelength at which wavelength conversion efficiency is maximized becomes the target wavelength. Laser device.

13. 2. The laser device according to claim 1, the wavelength conversion system outputs the second pulsed laser beam which is a first harmonic beam of the first pulsed laser beam. Laser device.

14. 2. The laser device according to claim 1, a solid-state laser device that outputs a fourth pulsed laser beam; the wavelength conversion system performs sum frequency conversion on the first pulse laser beam and the fourth pulse laser beam to output a second pulse laser beam. Laser device.

15. 15. The laser device of claim 14, The solid-state laser device is a second semiconductor laser that outputs a second continuous wave laser beam; a second amplifier that pulses and amplifies the second laser beam to output a fifth pulsed laser beam; a second nonlinear crystal that receives the fifth pulsed laser beam and outputs second harmonic light, which is the fourth pulsed laser beam; Including, Laser device.

16. 2. The laser device according to claim 1, the first semiconductor laser is at least one of a distributed feedback semiconductor laser, a distributed Bragg reflector semiconductor laser, and a sampled grating distributed Bragg reflector semiconductor laser; Laser device.

17. 17. The laser device of claim 16, a current flowing through a phase adjustment region of the distributed Bragg reflector semiconductor laser is controlled to change the wavelength of the first semiconductor laser; Laser device.

18. 17. The laser device of claim 16, changing the wavelength of the first semiconductor laser by controlling a current flowing through a phase adjustment region of the sampled grating distributed reflector semiconductor laser; Laser device.

19. A wavelength control method for a laser device, comprising: outputting a continuous wave first laser beam from a first semiconductor laser; pulsing and amplifying the first laser beam to output a first pulsed laser beam; outputting a second pulsed laser beam by wavelength conversion using the first pulsed laser beam; amplifying the second pulsed laser beam to output a third pulsed laser beam; measuring a wavelength of the third pulsed laser beam; periodically changing a target wavelength of the third pulsed laser beam; controlling a current for changing the wavelength of the first semiconductor laser based on a measurement value of the wavelength of the third pulse laser beam outputted at the same target wavelength so that the wavelength of the third pulse laser beam becomes the target wavelength; Including, A method for controlling wavelength of a laser device.

20. A method for manufacturing an electronic device, comprising: a first wavelength-tunable semiconductor laser that outputs a first continuous wave laser beam; a first amplifier that pulses and amplifies the first laser beam and outputs a first pulsed laser beam; a wavelength conversion system that outputs a second pulsed laser beam by wavelength conversion using the first pulsed laser beam; an excimer amplifier that amplifies the second pulsed laser beam and outputs a third pulsed laser beam; a monitor module that measures the wavelength of the third pulsed laser beam; a processor that periodically changes a target wavelength of the third pulse laser beam, and controls a current for changing the wavelength of the first semiconductor laser based on a measurement value of the wavelength of the third pulse laser beam output at the same target wavelength so that the wavelength of the third pulse laser beam becomes the target wavelength; generating the third pulsed laser beam by a laser device comprising: outputting the third pulsed laser beam to an exposure device; exposing a photosensitive substrate to the third pulsed laser beam in the exposure apparatus to manufacture an electronic device; A method for manufacturing an electronic device, comprising:

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