JP2016058742A - Laser light source device for extreme ultraviolet light source device, and laser light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably correct a wave face of laser beams varied by heat in an EUV light source device.SOLUTION: In an amplifying system 30 for amplifying laser beams output from a laser oscillation unit 20, at least one or more of wave face correcting units 34 and a sensor 36 are provided. The sensor 36 detects an angle (a direction) of the laser beams and variations of curvature ratio of a wave face, and outputs them. A wave face correcting controller (WFC-C) 50 outputs a signal to the wave face correcting unit 34 on the basis of measured result by the sensor 36. The wave face correcting unit 34 corrects wave faces of the laser beams to a specific wave face in accordance with an instruction from the wave face correcting controller (WFC-C) 50. Another wave face correcting unit and sensor can be provided also in a focusing system 40 which supplies the laser beams into a chamber 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an extreme ultraviolet light source device, a laser light source device for an extreme ultraviolet light source device, and a method for adjusting a laser light source device for an extreme ultraviolet light source device.

  For example, a semiconductor chip is generated by reducing and projecting a mask on which a circuit pattern is drawn on a resist-coated wafer and repeating processes such as etching and thin film formation. With the miniaturization of semiconductor processes, light having a shorter wavelength is required.

  Therefore, a semiconductor exposure technique using light with an extremely short wavelength of 13.5 nm and a reduction optical system has been studied. This technique is called EUVL (Extreme Ultra Violet Lithography). Hereinafter, extreme ultraviolet light is referred to as EUV light.

  Three types of EUV light sources are known: LPP (Laser Produced Plasma) type light sources, DPP (Discharge Produced Plasma) type light sources, and SR (Synchrotron Radiation) type light sources.

  The LPP type light source is a light source that generates plasma by irradiating a target material with laser light (laser beam) and uses EUV light emitted from the plasma. The DPP type light source is a light source that uses plasma generated by discharge. The SR type light source is a light source that uses orbital radiation. Among the above three types of light sources, the LPP type light source can increase the plasma density and can increase the collection solid angle as compared with other methods, so that there is a possibility that high output EUV light can be obtained. high.

  Therefore, in order to obtain high-output driver laser light at a high repetition frequency, a laser light source device configured according to a MOPA (master oscillator power amplifier) method has been proposed (Patent Document 1).

  A technique for adjusting the wavefront of laser light using a deformable mirror that can be variably controlled to a certain degree of surface shape is known (Patent Document 2).

JP 2006-128157 A JP 2003-270551 A

Overview

  For example, in order to obtain EUV light of about 100 W to 200 W, the output of the carbon dioxide laser as the driver laser light needs to be about 10 to 20 kW. When such high-power laser light is used, various optical elements in the optical path absorb light and become high temperature, and the wavefront shape and direction of the laser light change. In the present specification, the wavefront of the laser light is described as including the shape and direction of the wavefront of the laser light.

  When a high-power laser beam passes through the lens or window, the shape or refractive index of the lens or window changes due to a temperature rise due to heat generation, so that the wavefront of the laser beam changes. For example, if the wavefront of the laser beam changes, the laser beam cannot be efficiently incident on the amplification region in the laser amplifier, so that the expected laser output cannot be obtained. Furthermore, since the focal position of the laser light incident into the chamber changes according to the wavefront change of the laser light, the target material cannot be efficiently irradiated with the laser light. descend.

  The present invention has been made in view of the above problems, and an object thereof is an extreme ultraviolet light source device capable of correcting the direction of a laser beam and the shape of a wavefront into a predetermined direction and a predetermined wavefront shape. Another object of the present invention is to provide a laser light source device for an extreme ultraviolet light source device and a method for adjusting a laser light source for an extreme ultraviolet light source device. Another object of the present invention is to control the direction of the laser light and the shape of the wavefront at a plurality of positions set on the optical path, and to prevent the correction at each position from competing with each other. An extreme ultraviolet light source device, a laser light source device for an extreme ultraviolet light source device, and a method for adjusting a laser light source for an extreme ultraviolet light source device. Further objects of the present invention will become clear from the description of the embodiments described later.

  In order to solve the above problems, an extreme ultraviolet light source device according to the present invention is an extreme ultraviolet light source device that generates extreme ultraviolet light by irradiating a target material with laser light to generate plasma, A target material supply unit for supplying the target material; a laser oscillator for outputting laser light; and an amplification system for amplifying the laser light output from the laser oscillator by at least one amplifier; A condensing system for irradiating the target material in the chamber with the laser light amplified by the amplification system, wherein at least the amplification system is provided on an optical path of the laser light, and the amplification Detect the direction and wavefront shape of the laser light in the system, or the laser in the amplification system A plurality of first detection units for detecting a beam parameter corresponding to the direction and the wavefront shape of the laser beam, and provided on the optical path of the laser beam, and detected by each of the plurality of first detection units. The plurality of first correction units for correcting the direction and the shape of the wavefront to a predetermined direction and a predetermined wavefront shape, and the plurality of first correction units according to detection results by the plurality of first detection units, respectively. A plurality of correction control units for respectively controlling correction operations by the correction unit, and the direction of the laser beam incident on the light collecting system and the shape of the wavefront by controlling the plurality of correction control units in an integrated manner A laser controller for correcting

  The laser light source device used in the extreme ultraviolet light source device according to the present invention includes a laser oscillator for outputting laser light, and the laser light output from the laser oscillator is amplified by at least one amplifier. And an aggregating system for causing the laser light amplified by the amplification system to enter the chamber of the extreme ultraviolet light source device, and at least the amplification system includes: A plurality of first correction units provided on an optical path for correcting the direction of the laser beam and the wavefront shape in the amplification system to a predetermined direction and a predetermined wavefront shape; and the plurality of first correction units. A plurality of correction control units for controlling each of the correction operations, and before entering the light collection system by comprehensively controlling the plurality of correction control units. Comprising a laser controller for correcting the direction and the wavefront shape of the laser light.

  Further, the method for adjusting a laser light source device used in the extreme ultraviolet light source device according to the present invention is such that the laser light source device amplifies the laser light output from the laser oscillator by at least one amplifier. And a light collection system for causing the laser light amplified by the amplification system to enter the chamber. The laser light is output from the laser oscillator and amplified by the amplifier. And at least two points on the optical path of the laser beam, and the directions and the wavefront shapes detected at the at least two points become a predetermined direction and a predetermined wavefront shape, respectively. And correcting the direction of the laser beam and the shape of the wavefront at at least two points on the optical path of the laser beam, The direction of the laser beam and the correction of the wavefront shape at at least two points on the optical path of the laser beam are comprehensively controlled to correct the direction of the laser beam and the shape of the wavefront incident on the condensing system. .

  Also, a method for controlling an extreme ultraviolet light source device that generates extreme ultraviolet light by irradiating the target material according to the present invention with laser light to generate plasma is output from the laser oscillator. An amplification system for amplifying the laser beam to be amplified by a plurality of amplifiers, which corresponds to the direction and wavefront shape of the laser beam in the amplification system, or the direction and wavefront shape of the laser beam in the amplification system Detection is performed by the detection step in accordance with a detection step of detecting at least two points on the optical path of the laser beam and a detection result of the detection step at the at least two points on the optical path of the laser beam. The direction of the laser beam and the shape of the wavefront at the at least two points are respectively a predetermined direction and A correction step of correcting the direction of the laser beam and the shape of the wavefront at at least two points on the optical path of the laser beam so as to obtain a constant wavefront shape, and the correction at the at least two points on the optical path of the laser beam. And an overall control step for overall control of the correction step.

  According to the present invention, at least in the amplification system, the direction of the laser beam and the shape of the wavefront can be corrected. Therefore, even if the refractive index distribution of the optical element in the amplification system is generated by heat or the shape is deformed, the direction of the laser beam and the shape of the wavefront can be adjusted, and the amplification performance of the amplification system is reduced. Can be suppressed.

  By providing the second correction unit and the second detection unit in the condensing system, the direction of the laser beam and the shape of the wavefront can be corrected even in the condensing system. Therefore, the target material in the chamber can be irradiated with laser light having a predetermined direction and a predetermined wavefront shape.

  When a plurality of first correction units are provided in the amplification system, the correction control unit controls the correction operation of each first correction unit in order from the one located upstream in the traveling direction of the laser beam. . Therefore, the direction and the shape of the wavefront can be corrected in order from the upstream side of the laser beam, and it is possible to prevent the correction operations from competing with each other.

  In addition, the correction operation by the first correction unit in the amplification system is controlled first, and then the correction operation of the second correction unit in the condensing system is controlled, thereby stabilizing the amplification characteristics of the laser beam. Later, the condensing characteristic of the laser beam can be stabilized.

The block diagram of the EUV light source device which concerns on 1st Example of this invention. Explanatory drawing of a saturable absorber. The graph which shows the temperature change of a saturable absorber. The block diagram of a wavefront corrector. The schematic diagram of a sensor. Another schematic diagram of a sensor. The flowchart of a wavefront correction process. The flowchart of the process in which a laser controller notifies completion of adjustment to an EUV light source controller. The block diagram of the EUV light source device which concerns on 2nd Example. The flowchart of a wavefront correction process. The block diagram of the EUV light source device which concerns on 3rd Example. The block diagram of an EUV chamber. The block diagram of an isolator. The flowchart of a wavefront correction process. The block diagram of the EUV light source device which concerns on 4th Example. Explanatory drawing which concerns on 5th Example and shows the arrangement | positioning method of a wave front corrector. Explanatory drawing following FIG. The block diagram of a wavefront curvature correction device according to the sixth embodiment. The block diagram of a wavefront curvature correction device according to the seventh embodiment. The block diagram of a wavefront curvature correction device according to the eighth embodiment. The block diagram of the wave front curvature correction device according to the ninth embodiment. The block diagram following FIG. The block diagram of a wave front curvature correction device concerning a 10th Example. The block diagram following FIG. The block diagram of a wavefront curvature correction device according to the eleventh embodiment. The block diagram following FIG. The whole block diagram of an EUV light source device. The block diagram of a wave front curvature correction device according to the twelfth embodiment. The structure figure of an angle corrector in connection with 13th Example. The block diagram of a wave front corrector according to the fourteenth embodiment. The block diagram of a wave front corrector in connection with 15th Example. The block diagram of a wave front corrector in connection with 16th Example. The block diagram of a wave front corrector according to the seventeenth embodiment. The block diagram of a wave front corrector according to the eighteenth embodiment. The block diagram of a sensor concerning 19th Example. The structure figure of a sensor concerning a 20th example. A configuration diagram of a sensor according to the twenty-first embodiment. The structure figure of a sensor concerning 22nd Example. The structure figure of a sensor according to the 23rd embodiment. A block diagram of a wavefront amendment controller concerning the 24th example. Explanatory drawing which concerns on 25th Example and shows the principal part of a chamber. The block diagram of an optical sensor part concerning a 26th Example. The block diagram of an optical sensor part concerning a 27th Example. Explanatory drawing which shows an interference fringe. The structure figure of an optical sensor part concerning a 28th example. A configuration diagram of the optical sensor unit according to the twenty-ninth embodiment. The block diagram of a light receiving element. Explanatory drawing which shows the relationship between the beam shape of a laser beam, and the output of a light receiving element. Explanatory drawing of an optical sensor part concerning 30th Example. Explanatory drawing following FIG. Explanatory drawing following FIG. A configuration diagram of an isolator according to a thirty-first embodiment. Explanatory drawing which shows the example of the preferable combination of an Example. The block diagram of the EUV light source device which concerns on 32nd Example. The block diagram of the EUV light source device which concerns on 33rd Example. The block diagram of the vapor deposition apparatus which concerns on 34th Example. Explanatory drawing which concerns on 35th Example and shows the relationship between a mirror and a wavefront curvature correction device. The rear view of a mirror. Sectional drawing of a mirror. The rear view of the mirror which concerns on 36th Example. Sectional drawing of a mirror. Sectional drawing of the mirror which concerns on 37th Example. Sectional drawing of the mirror which concerns on 38th Example.

Embodiment

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, as described below, at least one correction means (34, 44) for correcting the wavefront of the laser light is provided on the optical path through which the laser light passes. By the correcting means, the traveling direction of the laser beam and the shape of the wavefront can be adjusted. In addition, although the laser light source device used for an extreme ultraviolet light source device is demonstrated, this invention is applicable also to laser light source devices other than the laser light source device for extreme ultraviolet light source devices.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram showing the overall configuration of the EUV light source apparatus 1. It should be noted that the characteristic configurations of the present invention shown in the following embodiments are not limited to the explicitly described combinations, and various combinations are possible, and such combinations also belong to the scope of the present invention.

  The EUV light source apparatus 1 includes, for example, a chamber 10 that generates EUV light, a laser light source apparatus 2 that supplies laser light to the chamber 10, and an EUV light source controller 70. The laser light source device 2 includes, for example, a laser oscillator (Master Oscillator) 20 that determines a time waveform and a repetition frequency of a laser pulse, an amplification system 30, a condensing system 40, a wavefront correction controller 50, and a laser controller 60. Consists of including. The EUV light source device 1 supplies EUV light to the EUV exposure device 5.

  First, an outline of the chamber 10 will be described. The chamber 10 includes, for example, a chamber body 11, a connection unit 12, a window 13, an EUV collector mirror 14, and a target material supply unit 15.

  The chamber body 11 is kept in a vacuum state by a vacuum pump (not shown). The chamber body 11 can be provided with a mechanism for collecting debris, for example.

  The connection unit 12 is provided to connect between the chamber 10 and the EUV exposure apparatus 5. The EUV light generated in the chamber body 11 is supplied to the EUV exposure apparatus 5 via the connection unit 12.

  The window 13 is provided in the chamber body 11. The driver laser light from the laser light source device 2 enters the chamber body 11 through the window 13.

  The EUV collector mirror 14 is a mirror for reflecting EUV light and collecting it at an intermediate focus (IF). The intermediate focus IF is set in the connection unit 12. The EUV collector mirror 14 is configured as a concave surface like a spheroid that ideally does not generate aberrations, for example, in order to transfer and image a plasma emission point image to the IF. On the surface of the EUV collector mirror 14, for example, a multilayer film composed of a molybdenum film and a silicon film is provided, so that EUV light having a wavelength of about 13 nm is reflected.

  The target material supply unit 15 supplies a target material such as tin, for example, as a liquid, a solid, or a gas. Tin can also be supplied as a tin compound such as stannane (SnH4). When supplying tin as a liquid, a method of supplying pure tin as a solution containing tin or a colloidal solution containing tin or a tin compound is possible in addition to a method of heating and liquefying pure tin to the melting point. In the present embodiment, description will be made by taking a tin droplet DP as an example of the target material, but the present invention is not limited to a tin droplet. For example, other substances such as lithium (Li) and xenon (Xe) may be used.

  The movement in the chamber 10 will be briefly described first. The driver laser beam is focused at a predetermined position in the chamber body 11 through the incident window 13. The target material supply unit 15 drops the tin droplet DP toward the predetermined position. The laser light source device 2 outputs a driver laser beam L1 having a predetermined output in time with the timing when the tin droplet DP reaches a predetermined position. The tin droplet DP is irradiated with the driver laser light L1 and becomes plasma PLZ. The plasma PLZ emits EUV light L2. The EUV light L <b> 2 is collected by the EUV collector mirror 14 at the intermediate focus IF in the connection unit 12 and supplied to the EUV exposure apparatus 5.

  Next, the configuration of the laser light source device 2 will be described. The laser light source device 2 is configured as a carbon dioxide pulse laser light source device and, for example, outputs a pulse of driver laser light L1 having a wavelength of 10.6 μm, a single transverse mode, a repetition frequency of 100 kHz, 100 to 200 mJ, and 10 kW to 20 kW. .

  Laser light output from the laser oscillator 20 is amplified by the amplification system 30 and sent to the light collection system 40. The condensing system 40 supplies the driver laser light L1 into the chamber 10. The condensing system 40 includes, for example, a reflecting mirror 41, an off-axis parabolic concave mirror 42, and a relay optical system 43. In the following description, the oscillator 20 side is referred to as the upstream side and the chamber 10 side is referred to as the downstream side with reference to the traveling direction of the laser light.

  The amplification system 30 includes, for example, a relay optical system 31, a preamplifier (preamplifier) 32, a saturable absorber 33, a wavefront corrector 34, a main amplifier (main amplifier) 35, and a sensor 36. Hereinafter, the saturable absorber 33 is referred to as SA (Saturable Absorber) 33. In the following description and drawings, the preamplifier is described as a preamplifier and the main amplifier is described as a main amplifier. Note that the output of the laser beam may be increased by using MOPA (Master Oscillator and Power Amplifier).

  The relay optical system 31 adjusts the beam divergence angle and the beam size of the laser light output from the laser oscillator 20 in order to efficiently fill the amplification region in the preamplifier 32 with the laser light output from the laser oscillator 20. This is an optical system. The relay optical system 31 expands the beam diameter of the laser beam output from the laser oscillator 20 and converts it into a predetermined beam beam.

  The preamplifier 32 amplifies and emits the incident laser beam. The laser light amplified by the preamplifier 32 is incident on the SA 33. SA33 is an element that exhibits a function of allowing laser light having a light intensity equal to or higher than a predetermined threshold to pass, and not allowing laser light having a light intensity lower than the predetermined threshold to pass. As a result, the SA 33 absorbs laser light (return light) returning from the chamber 10, parasitic oscillation light from the main amplifier and self-oscillation light, and prevents damage to the preamplifier 32 and the laser oscillator 20. Furthermore, SA33 also plays a role of suppressing the pedestal and improving the quality of the pulse waveform of the laser beam. A pedestal is a small pulse that occurs close in time to the main pulse.

  FIG. 2 shows a configuration example of SA33. The SA 33 includes, for example, a holder 330 with a water cooling jacket (not shown), two windows 332 and 333 attached to the holder 330, an inlet 334 into which sulfur hexafluoride gas (SF 6 gas) flows, and SF 6 gas. And an outflow port 335 for causing the gas to flow out.

  The laser light L1 amplified by the preamplifier 32 enters through the left incident window 332 and passes through the left emission window 333. SF6 gas supplied to the gap between each of 332 and 333 has a function of absorbing carbon dioxide laser light.

  FIG. 3 is a graph showing the temperature distribution occurring in SA33. SF6 gas flows into the gaps between the windows 332 and 333 from the inflow port 334, absorbs laser light below the threshold value, and flows out from the outflow port 335. As a result, a temperature distribution that shifts in the flow direction of the SF6 gas is generated in SA33. Due to the temperature distribution of the SA33 window, the refractive index distribution of the window changes.

  As a result, the laser beam L1 passing through the SA 33 is shifted in the direction AX1e shifted from the reference optical axis AX1, as indicated by a broken line L1e in FIG. The wavefront (Wave Front) of the laser beam L1 passing through SA33 does not change concentrically while holding the reference optical axis AX1, but bends along the axis AX1e. That is, when the laser beam L1 passes through the SA33, the direction of the laser beam is deviated, and the wavefront shape also changes.

  Even if the laser light L1e having a shifted traveling direction or wavefront shape is incident on the main amplifier 35 as it is, the expected amplification action cannot be obtained. This is because the amplification region of the main amplifier 35 cannot be efficiently filled with laser light.

  In order to solve this problem, in this embodiment, a wavefront corrector 34 as a “first corrector” is provided between the SA 33 and the main amplifier 35. In the following description and drawings, the wavefront compensator may be displayed as WFC (Wave Front Compensator).

  FIG. 4 is an explanatory diagram schematically showing the principle of the wavefront corrector 34. The upper side of FIG. 4 shows a case where the thermal load applied to the amplification system 30 is small. The lower side of FIG. 4 shows a case where the heat load applied to the amplification system 30 is large.

  The wavefront corrector 34 includes an angle corrector 100 and a wavefront curvature corrector 200. The angle corrector 100 is an optical system for adjusting the angle (traveling direction) of laser light. The wavefront curvature corrector 200 is an optical system for adjusting the curvature (beam spread) of the wavefront of laser light. A specific structural example will be described later as another embodiment.

  The angle corrector 100 includes, for example, two reflection mirrors 101 and 102 that are arranged in parallel to face each other. As shown on the lower side of FIG. 4, each of the reflection mirrors 101 and 102 is pivoted about the X axis (axis perpendicular to FIG. 4) and Y axis (axis orthogonal to the X axis) of the reflection mirror. As shown in FIG. That is, the reflecting mirrors 101 and 102 are attached so as to be able to tilt and roll.

  When the thermal load is small, the laser light L1 travels in accordance with the reference optical axis, and therefore it is not necessary to change the posture of each of the reflection mirrors 101 and 102. When the thermal load is large, the laser beam L1e is incident off the reference optical axis. Therefore, the postures of the reflecting mirrors 101 and 102 are appropriately changed so that the laser light emission direction matches the reference optical axis.

  The wavefront curvature corrector 200 is formed by a convex lens 201 and a concave lens 202, for example. By adjusting the relative positional relationship between the lenses 201 and 202, a concave wave or a convex wave can be corrected to a plane wave.

  The wavefront correction controller 50 as the “correction control unit” appropriately drives the angle corrector 100 and the wavefront curvature corrector 200 so as to eliminate the deviation from the target value based on the measurement result by the sensor 36. As a result, the wavefront corrector 34 corrects the angle of the incident laser beam and the curvature of the wavefront to a predetermined angle and a predetermined curvature, and emits them. The wavefront corrector 34 enlarges and outputs the laser beam diameter so as to obtain a beam angle and a wavefront curvature necessary for high-efficiency amplification by the main amplifier, and converts the laser beam into a predetermined laser beam flux. The converted laser light is amplified by the main amplifier 35.

  The sensor 36 as a “first detection unit” is provided on the downstream side of the main amplifier 35 and detects the angle of the incident laser beam and the curvature of the wavefront. The sensor 36 may have any configuration that can directly or indirectly measure the angle of the laser beam and the curvature of the wavefront.

  The outline of the sensor 36 will be described with reference to FIGS. Another configuration example of the sensor 36 will be described later as another embodiment. As shown in the principle diagram of FIG. 5, the sensor 36 includes, for example, a reflection mirror 300 that reflects the laser light L <b> 1 and an optical sensor unit 360 that measures the laser light L <b> 1 </ b> L that slightly passes through the reflection mirror 300. Composed.

  FIG. 6 shows an example of the sensor 36. The reflection mirror 300 coated with a film that reflects the laser light L1 with high reflectivity includes a beam splitter substrate 300A and a holder 300B with a water cooling jacket (not shown) for holding the beam splitter substrate 300A.

  The beam splitter substrate 300A is made of a material such as silicon (Si), zinc selenide (ZnSe), gallium arsenide (GaAs), or diamond. Most of the laser light L1 is reflected by the highly reflective film of the beam splitter substrate 300A, but there is a laser light L1L that passes through the beam splitter substrate 300A very slightly.

  The laser beam L1L slightly transmitted through the beam splitter substrate 300A enters the optical sensor unit 360 as sample light. Examples of the optical sensor unit 360 include a beam profiler for measuring the intensity distribution of the laser beam, a power sensor (such as a calorimeter and a pyro sensor) for measuring the laser duty and the load of the optical element, and the wavefront state of the laser beam. A wavefront sensor or the like that can measure the direction and the direction can be used.

  Further, as will be described later, the wavefront state and angle (direction) of the laser beam are determined by using parameters (temperature, operation command value, etc.) related to the laser beam state and a database obtained from simulations and experimental results. It may be predicted.

  Next, the control system will be described. As shown in FIG. 1, the EUV light source device 1 includes a wavefront correction controller 50, a laser controller 60, and an EUV light source controller 70.

  FIG. 7 is a flowchart showing wavefront correction processing executed by the wavefront correction controller 50. This process is performed at the start-up before the laser light source device 2 starts operation. That is, in the adjustment stage before the operation of the laser light source device 2 is started, first, before irradiating the target, for example, a shutter (not shown) is closed so that the laser beam is not incident on the EUV chamber 10, and then the laser is turned on. Adjust oscillation. When the seed light is output from the laser oscillator 20, the wavefront and the angle (direction) of the laser beam line downstream from the laser oscillator 20 are adjusted so that the amplification efficiency of the main amplifier 35 is maintained high. Each flowchart described below shows an outline of each process, and may differ from an actual computer program. A so-called person skilled in the art will be able to change or delete the illustrated steps and add new steps. Hereinafter, the direction of the laser beam may be referred to as “angle”.

  The wavefront correction controller 50 acquires a measured value from the sensor 36 (S10), and calculates a deviation ΔD that is a difference between the target value and the measured value (S11). The wavefront correction controller 50 determines whether or not the absolute value of ΔD is equal to or less than a predetermined allowable value DTh (S12). The allowable value DTh is set, for example, as a value that does not affect the amplification characteristics of the laser light.

  When the difference ΔD between the target value and the measured value is less than or equal to the allowable value DTh (S12: YES), the wavefront correction controller 50 outputs an OK signal to the laser controller 60 (S13). The OK signal is an adjustment completion signal that means that the wavefront of the laser beam has been adjusted to a predetermined wavefront (curvature and direction).

  On the other hand, when the absolute value of ΔD exceeds the allowable value DTh (S12: NO), the wavefront correction controller 50 outputs an NG signal to the laser controller 60 (S14). The NG signal is an adjustment incomplete signal that means that the wavefront of the laser beam is not adjusted to a predetermined wavefront.

  The wavefront correction controller 50 outputs a drive signal to the wavefront corrector 34, and causes the wavefront corrector 34 to perform a correction operation (S15). The wavefront corrector 34 operates the angle corrector 100 and the wavefront curvature corrector 200 according to the drive signal. By executing the correction operation once or a plurality of times, the wavefront of the laser light coincides with a predetermined wavefront.

  FIG. 8 is a flowchart showing the operation of the laser controller 60 and the operation of the EUV light source controller 70. When receiving the OK signal from the wavefront correction controller 50 (S20: YES), the laser controller 60 notifies the EUV light source controller 70 that the adjustment of the laser light source device 2 has been completed (S21).

  Upon receiving the adjustment completion notification from the laser controller 60, the EUV light source controller 70 supplies the droplet DP from the target material supply unit 15 to the chamber body 11 (S22).

  The laser controller 60 outputs the laser light L1 from the laser oscillator 20 in accordance with the supply timing of the droplet DP. The laser light L1 is amplified by the amplification system 30 and then enters the chamber 10 via the light collection system 40. The droplet DP becomes plasma PLZ by being irradiated with the laser light L1. The EUV light L2 emitted from the plasma PLZ is collected at the intermediate focus IF by the EUV collector mirror 14 and sent to the EUV exposure apparatus 5.

  As described above, in this embodiment, in the amplification system 30 for amplifying the laser beam output from the laser oscillator 20, the wavefront corrector 34 for adjusting the curvature and direction of the wavefront of the laser beam, and the laser beam And a sensor 36 for detecting the curvature and direction of the wavefront. Therefore, in the present embodiment, the wavefront corrector 34 can adjust the curvature and direction (angle) of the wavefront of the laser light before the operation of the laser light source device 2 is started. As a result, the output characteristics of the laser beam can be stabilized even in an operating state where the thermal load is high.

  In this embodiment, since the angle (direction) of the laser beam and the curvature of the wavefront are corrected in the amplification system 30, the condensing characteristic of the laser beam sent to the chamber 10 via the condensing system 40 is also maintained to a certain degree of stability. can do.

  As described above, in this embodiment, the laser beam having a stable output can be condensed at a predetermined position (the focal position of the EUV collector mirror and the target) in the chamber 10. Therefore, the EUV light source device 1 of the present embodiment can stably generate high-power EUV light.

  A second embodiment will be described with reference to FIGS. Each embodiment described below is a modification of the first embodiment. Therefore, the difference from the first embodiment will be mainly described. In the present embodiment, the condensing system 40 is also provided with a mechanism (wavefront corrector 44, sensor 45, wavefront correction controller 50 (2)) for performing wavefront correction.

  FIG. 9 is an explanatory diagram showing the overall configuration of the EUV light source apparatus 1 according to the present embodiment. In the present embodiment, a second wavefront corrector 44 as a “second correction unit” and a second sensor 45 as a “second detection unit” are provided in the light collection system 40.

  Further, in this embodiment, in addition to the first wavefront correction controller 50 (1) for correcting the laser light in the amplification system 30, the second wavefront correction controller for correcting the laser light in the light collection system 40. 50 (2).

  FIG. 10 is a flowchart showing the operation of this embodiment. In the present embodiment, as described below, the curvature and direction (angle) of the wavefront of the laser beam are corrected in order from the upstream side. First, the wavefront correction controller 50 (1) that controls the wavefront corrector 34 in the amplification system 30 acquires a measured value from the sensor 36 (S30), and calculates a deviation ΔD1 (S31).

  The wavefront correction controller 50 (1) determines whether or not the absolute value of the deviation ΔD1 is equal to or less than the allowable value DTh1 (S32). When the absolute value of ΔD1 is equal to or smaller than the allowable value DTh1 (S32: YES), the wavefront correction controller 50 (1) outputs an OK signal to the laser controller 60 (S33).

  When the absolute value of ΔD1 exceeds the allowable value DTh1 (S32: NO), the wavefront correction controller 50 (1) outputs an NG signal to the laser controller 60 (S34). The wavefront correction controller 50 (1) instructs the wavefront corrector 34 to execute a correction operation for reducing the difference between the target value and the measured value (S35).

  When the laser controller 60 receives the OK signal from the wavefront correction controller 50 (1) (S40: YES), the laser controller 60 notifies the wavefront correction controller 50 (2) that manages the wavefront corrector 44 that the previous wavefront correction has been completed. (S41). This notification is shown as “OK signal 1” in FIG.

  The wavefront correction controller 50 (2) acquires the measurement value from the sensor 45 (S50), and calculates ΔD2 that is the difference between the target value and the measurement value (S51). The wavefront correction controller 50 (2) determines whether or not a notification that the previous correction process has been completed has been received from the laser controller 60 (S52).

  Until the wavefront correction by the wavefront correction controller 50 (1) at the previous stage is completed (S52), the wavefront correction controller 50 (2) repeatedly executes S50 and S51. When the wavefront correction by the wavefront correction controller in the previous stage is completed (S52: YES), the wavefront correction controller 50 (2) determines whether or not the absolute value of ΔD2 calculated in S51 is equal to or less than the allowable value DTh2 (S53). ).

  When the absolute value of ΔD2 is equal to or smaller than the allowable value DTh2 (S53: YES), the wavefront correction controller 50 (2) outputs an OK signal to the laser controller 60 (S54). When the absolute value of ΔD2 exceeds the allowable value DTh2 (S53: NO), the wavefront correction controller 50 (2) outputs a drive signal to the wavefront corrector 44, and the curvature and direction (angle) of the wavefront of the laser light. ) Is performed (S56).

  When the laser controller 60 receives the OK signal from the second wavefront correction controller 50 (2) (S42: YES), it notifies the EUV light source controller 70 that the adjustment of the laser light source device 2 has been completed (S43).

  Thus, in this embodiment, after confirming the end of the wavefront correction process on the upstream side (in the amplification system), the wavefront correction process on the downstream side (in the condensing system) is performed. Accordingly, the wavefront correction by the wavefront correction controller 50 (1) and the wavefront correction by the wavefront correction controller 50 (2) compete with each other, and sufficient wavefront correction cannot be performed or the wavefront correction fails. Can be prevented.

  This embodiment has the same effect as the first embodiment. Furthermore, in this embodiment, since the wavefront correction of the laser light is also performed in the light condensing system 40, the light condensing performance can be further stabilized.

  A third embodiment will be described with reference to FIGS. In the present embodiment, the wavefront correctors 34 (1), 34 (2), 34 (3), and 34 (3) are added to the amplifiers 32 (1), 32 (2), 35 (1), and 35 (2) in the amplification system 30. 34 (4) is associated, and the wavefront correction of the laser beam is performed every time the laser beam is amplified.

  FIG. 11 is an overall configuration diagram of the EUV light source apparatus 1 according to the present embodiment. In this embodiment, two slab type preamplifiers 32 (1) and 32 (2) are used as preamplifiers. The laser light is amplified by traveling along the zigzag optical path of the slab type preamplifiers 32 (1) and 32 (2). Corresponding to the provision of a plurality of preamplifiers, a plurality of main amplifiers 35 (1) and 35 (2) are provided. That is, the pulsed light output from the MO 20 is amplified by a plurality of preamplifiers. The amplified pulse light is further amplified by passing through a plurality of main amplifiers. Each amplifier is arranged in series so that the pulsed light is amplified.

  On the output side of the laser oscillator 20, a spatial filter 37 for improving the spatial transverse mode is provided. Furthermore, SA33 (1) is provided at the exit of the preamplifier 32 (1), and SA33 (2) is provided at the exit of another preamplifier 32 (2).

  A wavefront corrector 34 (1) and a sensor 36 (1) are provided on the downstream side (laser beam emission side) of the first SA 33 (1). A wavefront corrector 34 (2) and a sensor 36 (2) are provided on the downstream side of the second SA 33 (2).

  The laser light that has passed through the sensor 36 (2) is reflected by the reflection mirrors 38 (1) and 38 (2), and enters the wavefront corrector 34 (3). The wavefront corrector 34 (3) is provided on the upstream side (laser beam incident side) of the main amplifier 35 (1). A sensor 36 (3) corresponding to the wavefront corrector 34 (3) is provided on the downstream side of the main amplifier 35 (1).

  A wavefront corrector 34 (4) is provided upstream of the last main amplifier 35 (2), and a sensor 36 (4) is provided downstream of the main amplifier 35 (2). .

  As described in the second embodiment, a wavefront corrector 44 and a sensor 45 are also provided in the light collection system 40. Further, in this embodiment, a polarization separation type isolator 46 is provided between the reflection mirror 41 (1) and the reflection mirror 41 (2).

  The state of laser light in the amplification system 30 and the condensing system 40 will be described. First, the laser light output from the laser oscillator 20 is transmitted through the spatial filter 37, so that the spatial transverse mode is improved. The laser beam with the improved spatial transverse mode enters the incident window of the slab type preamplifier 32 (1), is amplified while passing in a zigzag manner between the two concave mirrors, and is emitted from the emission window.

  The laser light amplified by the preamplifier 32 (1) passes through SA33 (1). Thereby, the laser beam below a predetermined threshold value is removed from the laser beam. When passing through SA33 (1), the curvature and direction (angle) of the wavefront of the laser light change as described with reference to FIG.

  Therefore, the laser beam affected by SA33 (1) is corrected by the wavefront corrector 34 (1). The wavefront correction controller (WFC1-C) 50 (1) detects the state of the laser light after wavefront correction based on the measurement value from the sensor 36 (1), and the curvature and angle of the wavefront of the laser light are set to a predetermined value. Thus, the wavefront corrector 34 (1) is controlled.

  The laser beam corrected by the wavefront corrector 34 (1) is input to the second preamplifier 32 (2) and amplified, and then passes through the SA33 (2). The laser beam that has passed through SA33 (2) is subjected to wavefront correction by the wavefront corrector 34 (2), as described above. The wavefront correction controller (WFC2-C) 50 (2) controls the wavefront correction unit 34 (2) so that the curvature and angle of the wavefront of the laser light have predetermined values based on the measurement value of the sensor 36 (2). A drive signal is output.

  The laser beam corrected by the wavefront corrector 34 (2) is incident on the wavefront corrector 34 (3) via the two reflecting mirrors 38 (1) and 38 (2). The wavefront correction controller 50 (3) controls the wavefront corrector 34 (3) based on the measurement value from the sensor 36 (3) provided on the outlet side of the main amplifier 35 (1). The wavefront correction controller (WFC3-C) 50 (3) operates the wavefront corrector 34 (3) to obtain a wavefront that can efficiently fill the laser amplification region of the main amplifier 35 (1) with laser light.

  The laser beam corrected by the wavefront corrector 34 (3) passes through the main amplifier 35 (1) and the sensor 36 (3) and enters the wavefront corrector 34 (4). As described for the wavefront corrector 34 (3), the wavefront correction controller (WFC4-C) 50 (4) is a measured value from the sensor 36 (4) provided on the outlet side of the main amplifier 35 (2). Based on the above, the wavefront corrector 34 (4) is controlled so that the curvature and angle of the wavefront of the laser light incident on the main amplifier 35 (2) become a predetermined value.

  Thus, in the present embodiment, the amplification system 30 amplifies the laser light a total of four times, and corrects the curvature and angle of the wavefront of the laser light. Thereby, the high-power laser beam emitted from the main amplifier 35 (2) at the final stage is stabilized.

  Laser light output from the amplification system 30 is input to a wavefront corrector 44 in the light collection system 40. The wavefront correction controller (WFC5-C) 50 (5) causes the wavefront correction unit 44 to perform wavefront correction based on a signal from the sensor 45 provided in front of the window 13 of the chamber 10A. Thereby, a laser beam having a predetermined plane wave is obtained.

  The laser light corrected by the wavefront corrector 44 passes through the polarization separation type isolator 46 and enters the reflection mirror 41 (2). The isolator 46 will be described later with reference to FIG. The laser beam reflected by the reflection mirror 41 (2) enters the window 13 of the chamber 10A via the sensor 45.

  FIG. 12 is an explanatory diagram showing the configuration of the chamber 10A according to the present embodiment. The chamber 10A is roughly divided into two regions 11 (1) and 11 (2). One region 11 (1) is a condensing region for adjusting laser light incident from the laser light source device 2. The other region 11 (2) is an EUV light emitting region for generating EUV light by irradiating the droplet DP with laser light.

  The two regions 11 (1) and 11 (2) are partitioned by a wall. The condensing region 11 (1) and the EUV light emitting region 11 (2) communicate with each other through a small hole formed in a partition wall that partitions the regions 11 (1) and 11 (2). The pressure in the condensing region 11 (1) can be set slightly higher than the pressure in the EUV light emitting region 11 (2). Thereby, it is possible to prevent debris generated in the EUV light emission region 11 (2) from entering the light collection region 11 (1).

  The laser light that has entered the focusing region 11 (1) from the window 13 is reflected by the off-axis parabolic convex mirror 18 and enters the off-axis parabolic concave mirror 16 (1). The laser light has a predetermined beam diameter by being reflected by the mirror 18 and the mirror 16 (1).

  The laser beam set to a predetermined beam diameter is incident on the reflection mirror 17 and reflected, and is incident on another off-axis parabolic concave mirror 16 (2). The laser light reflected by the off-axis parabolic concave mirror 16 (2) enters the EUV light emission region 11 (2), and irradiates the droplet DP through the hole 14 A of the EUV collector mirror 14.

  It should be noted that the windows included in each amplifier 32 (1), 32 (2), 35 (1), 35 (2), the windows included in each SA 33 (1), 33 (2), the window 13 of the chamber 10A, and the like. As described above, the window through which the laser beam passes is preferably formed from a material having characteristics such as diamond.

  Diamond is transparent to the wavelength of 10.2 μm of the CO 2 laser and has high thermal conductivity. Therefore, even when a large heat load is applied, the temperature distribution is unlikely to occur, and the shape and refractive index are unlikely to change. Therefore, the curvature and angle of the wavefront of the laser light passing through the diamond window are unlikely to change.

  However, since diamond is generally expensive, it may be difficult in terms of cost to make all windows diamond windows. If cost is taken into consideration, a diamond window can be used as a window used for a device having a relatively large heat load. In this laser system, except for SA33, the heat load increases as it goes downstream, so for example, a relatively large heat load is applied to both windows of the main amplifier 35 and the window of the EUV chamber 10A. It is good to use a made window. Furthermore, since SA33 absorbs CO2 laser light, the heat load increases. Therefore, it is preferable to use a diamond window for SA33 regardless of whether it is provided upstream or downstream of the beam.

  FIG. 13 is an explanatory diagram showing a configuration example of the isolator 46. The isolator 46 includes, for example, a first mirror 461 including a heat sink 460, a second mirror 462, and a third mirror 463. The condensing optical system for condensing the laser light in the chamber 10A is installed on the laser light reflected by the third mirror 463 via the reflecting mirror 41 (2) and the window 13 (see FIG. 12). The light enters the condensing region 11 (1).

  The first mirror 461 transmits P-polarized light and reflects only S-polarized light by the dielectric multilayer film provided on the surface thereof. The first mirror 461 is cooled by the heat sink 460 after the P-polarized light is absorbed by the substrate. The laser light is incident on the first mirror 461 as S-polarized light.

  The S-polarized laser light reflected by the first mirror 461 is incident on a second mirror 462 provided to face the first mirror 461 in an oblique direction. A λ / 4 film that generates a phase difference of π / 2 is formed on the surface of the second mirror 462. Accordingly, the laser beam is converted into circularly polarized light by being reflected by the second mirror 462.

  Circularly polarized laser light is incident on the third mirror 463. The third mirror 463 is coated with a film that reflects P-polarized light and S-polarized light with high reflectance. The laser beam reflected by the third mirror 463 is focused and irradiated on the droplet via the condensing region 11 (1) where the condensing optical system for condensing the laser beam is installed to irradiate the plasma PLZ. generate.

  The laser light reflected by the plasma PLZ returns as the circularly polarized light in the reverse direction to the same optical path as that during irradiation. The circularly polarized return light is reflected by the third mirror 463 and enters the second mirror 462. The laser beam is converted into P-polarized light by being reflected by the λ / 4 film of the second mirror 462.

  The P-polarized laser light is incident on the first mirror 461. The P-polarized laser light incident on the first mirror 461 passes through the film of the first mirror 461, is absorbed by the mirror substrate, and changes to heat. The heat is radiated by the heat sink 460. Therefore, it is possible to prevent the laser light reflected and returned by the plasma PLZ from returning to the entrance side of the isolator 46. Thereby, the self-excited oscillation by the return light of the driver laser beam L1 can be prevented.

  By using the reflection optical system isolator 46 as shown in FIG. 13, the distortion of the wavefront generated in the laser light passing through the isolator 46 can be reduced as compared with the case of using the transmission optical system isolator.

  FIG. 14 is a flowchart showing an outline of the operation according to this embodiment. As described in the second embodiment, when a plurality of wavefront correctors are provided, wavefront correction is performed in order from the upstream wavefront corrector.

  First, the wavefront correction controller 50 (1) performs the first wavefront correction using the wavefront corrector 34 (1) located on the most upstream side (S35), and notifies the laser controller 60 that the correction has been completed. (S32).

  Next, the wavefront correction controller 50 (2) confirms that the completion notification has been issued from the preceding wavefront correction controller 50 (1) (S52), and then uses the wavefront corrector 34 (2) to perform the second operation. Wavefront correction is executed (S56). The wavefront correction controller 50 (2) notifies the laser controller 60 that the wavefront correction has been completed (S54).

  Similarly, the next wavefront correction controller 50 (3) confirms that a completion notice has been issued from the preceding wavefront correction controller 50 (2) (S62), and uses the wavefront corrector 34 (3). The third wavefront correction is executed (S66). The wavefront correction controller 50 (3) notifies the laser controller 60 that the wavefront correction has been completed (S64).

  Similarly, the wavefront correction controller 50 (4) confirms that the completion notification is issued from the preceding wavefront correction controller 50 (3) (S72), and uses the wavefront corrector 34 (4) to perform the fourth operation. Wavefront correction is performed (S76). The wavefront correction controller 50 (4) notifies the laser controller 60 that the wavefront correction has been completed (S74).

  The final wavefront correction controller 50 (5) confirms that the completion notification is issued from the preceding wavefront correction controller 50 (4) (S82), and then performs the final wavefront correction using the wavefront corrector 44. (S86). The wavefront correction controller 50 (5) notifies the laser controller 60 that the wavefront correction has been completed (S84).

  The laser controller 60 sequentially receives completion notifications to the effect that the wavefront correction has been completed from the wavefront correction controllers 50 (1) to 50 (5). Upon receiving all completion notifications, the laser controller 60 notifies the EUV light source controller 70 that the adjustment of the laser light source device 2 has been completed.

  Configuring this embodiment like this also achieves the same effects as the first and second embodiments. Furthermore, in this embodiment, the wavefront correctors 34 (1) to 34 (5) are associated with the amplifiers 32 (1), 32 (2), 35 (1), and 35 (2) in the amplification system 30, Laser light is incident on each amplifier with an appropriate wavefront curvature and angle. Therefore, the laser beam can be amplified more stably than in the first and second embodiments.

  A fourth embodiment will be described with reference to FIG. In this embodiment, a total of four preamplifiers 32 (1) to 32 (4) and a total of two main amplifiers 35 (1) and 35 (2) are provided. In this embodiment, only one SA33 is provided compared to the third embodiment.

  In the amplification system of this embodiment, the spatial filter 37, the relay optical system 31 (1), the preamplifier 32 (1), the relay optical system 31 (2), the preamplifier 32 (2), SA33, and wavefront correction are sequentially performed from the upstream side. 34 (1), sensor 36 (1), wavefront corrector 34 (2), preamplifier 32 (3), sensor 36 (2), wavefront corrector 34 (3), preamplifier 32 (4), sensor 36 (3 ), Reflection mirror 38 (1), reflection mirror 38 (2), wavefront corrector 34 (4), main amplifier 35 (1), sensor 36 (4), wavefront corrector 34 (5), main amplifier 35 (2). ), Sensor 36 (5).

  The wavefront corrector 34 (1) corrects the laser light that passes through the two preamplifiers 32 (1), 32 (2) and the SA 33. A sensor 36 (1) corresponding to the wavefront corrector 34 (1) is provided on the downstream side of the wavefront corrector 34 (1). Variation examples of the positional relationship among the wavefront corrector 34, the sensor 36, and elements (SA, preamplifier, main amplifier) that cause wavefront changes will be described later with reference to FIGS.

  The wavefront corrector 34 (2) corrects the laser light passing through the preamplifier 32 (3). Similarly, the wavefront corrector 34 (3) corrects the laser light passing through the preamplifier 32 (4). The wavefront corrector 34 (4) corrects the laser light passing through the main amplifier 35 (1). The wavefront corrector 34 (5) corrects the laser light passing through the main amplifier 35 (2).

  In this embodiment configured as described above, similarly to the third embodiment, the upstream wavefront corrector is used in order to correct the curvature and angle of the wavefront of the laser light. This embodiment also has the same effect as the third embodiment.

  Further, in this embodiment, the laser light having a distorted wavefront is corrected by the two wavefront correctors 34 (1) by the two upstream preamplifiers 32 (1), 32 (2) and SA33. Since the upstream side has a smaller thermal load than the downstream side, a plurality of elements (32 (1), 32 (2), 33) that can generate wavefront changes are handled by one wavefront compensator 34 (1). It is also possible to make it. Thereby, the manufacturing cost of the laser light source device 2 can be reduced. In the following description, an element that can generate a wavefront change may be referred to as a wavefront change generation unit.

  A fifth embodiment will be described with reference to FIGS. In this embodiment, a modified example of the positional relationship among the wavefront corrector 34, the sensor 36, and the wavefront change generators (32, 35, 33, etc.) will be described. The wavefront corrector includes a wavefront corrector 34 in the amplification system and a wavefront corrector 44 in the condensing system 40. In the following description, the wavefront corrector 34 will be described as a representative.

  Examples of the wavefront change generator that can change the wavefront by a thermal load include a preamplifier 32, a main amplifier 35, SA33, a relay optical system 31, a reflection mirror, a polarizing element, a retarder, and other various optical elements. Here, for convenience of explanation, the preamplifier 32, the main amplifier 35, and the SA33 are mainly described as examples of the wavefront change generation unit.

  FIG. 16A shows a configuration in which the wavefront corrector 34 is arranged upstream of the wavefront change generators 32, 35, 33 and the sensor 36 is arranged downstream of the wavefront change generators 32, 35, 33. The laser light is corrected by the wavefront corrector 34 and then input to the sensor 36. The wavefront correction controller 50 controls the wavefront corrector 34 so that the characteristics (curvature and angle of the wavefront) of the laser light measured by the sensor 36 have predetermined characteristics.

  FIG. 16B shows a case where the wavefront corrector 34 and the sensor 36 are arranged on the downstream side of the wavefront change generators 32, 35, 33. The wavefront corrector 34 is provided between the wavefront change generators 32, 35, 33 and the sensor 36.

  The laser light enters the wavefront corrector 34 after passing through the relay optical system 31 and the wavefront change generators 32, 35, and 33. The wavefront correction controller 50 controls the wavefront corrector 34 so that the laser light characteristic (also referred to as beam characteristic) detected by the sensor 36 has a predetermined characteristic.

  FIG. 16C shows a configuration in which the wavefront corrector 34 and the sensor 36 are arranged on the upstream side of the wavefront corrector 34. A sensor 36 is provided between the wavefront corrector 34 and the wavefront change generators 33, 35, and 32. The wavefront correction controller 50 controls the wavefront corrector 34 so that the laser light characteristic detected by the sensor 36 becomes a predetermined characteristic.

  In FIG. 16 (c), the wavefront correction controller 50 predicts wavefront distortion that may occur in the wavefront change generation units 32, 33, and 35, and the laser light is converted into the wavefront correction unit 34 and the wavefront change generation units 32, 33, and 35. The wavefront corrector 34 is controlled so that the wavefront returns to the normal wavefront when passing through.

  As shown in FIG. 17, a plurality of wavefront correctors 34 or a plurality of sensors 36 may be provided. As shown in FIG. 17 (a), sensors 36 (1) and 36 (2) are arranged upstream and downstream of the wavefront change generators 32, 33 and 35, respectively, and a wavefront corrector 34 is provided at the most upstream. Deploy.

  The wavefront correction controller 50 uses the laser light characteristics detected by the sensor 36 (1) and the laser light characteristics detected by the sensor 36 (2) in each of the sensors 36 (1) and 36 (2). The wavefront corrector 34 is controlled so that the predetermined characteristic is measured.

  In FIG. 17B, the wavefront corrector 34 and the sensor 36 are arranged on the upstream side and the downstream side of the wavefront change generating units 32, 33, and 35, respectively. The wavefront corrector 34 (1) and the sensor 36 (1) are provided upstream of the wavefront change generators 32, 33, and 35. The wavefront corrector 34 (2) and the sensor 36 (2) are provided on the downstream side of the wavefront change generators 32, 33, and 35.

  The laser light that has passed through the sensor 36 (1) passes through the wavefront change generators 32, 33, and 35, is then input to the wavefront corrector 34 (2), and further passes through the wavefront corrector 34 (2). , Input to the sensor 36 (2). The wavefront correction controller 50 adjusts the wavefront correctors 34 (1) and 34 (34) so that the laser light characteristics measured at the respective positions of the sensors 36 (1) and 36 (2) become the predetermined characteristics at the respective positions. 2) is controlled.

  A sixth embodiment will be described with reference to FIG. In the present embodiment, a case where the wavefront curvature corrector 200 is configured by a transmission optical system will be described. As shown in FIG. 18, the wavefront curvature corrector 200 can be configured using a convex lens 201 and a concave lens 202.

  FIG. 18A shows a state in which an input plane wave is output as a plane wave. If the focal position of the convex lens 201 and the focal position of the concave lens 202 coincide with each other at the confocal point cf, when the laser light passes through the convex lens 201 in a plane wave state, it is converted into a concave wave surface. When the concave wave surface laser light passes through the concave lens 202, it is converted into a plane wave.

  FIG. 18B shows how a convex wave is converted to a plane wave. The convex lens 201 has moved to the upstream side (left side in FIG. 18) from the position shown in FIG. The focal position F1 of the convex lens 201 and the focal position F2 of the concave lens are respectively located on the optical axis of the laser beam, and the focal point F1 of the convex lens 201 is located on the upstream side.

  When the laser light changes to a convex wave due to the influence of heat in the wavefront change generation units 32, 33, and 35, the laser light enters the convex lens 201 in a divergent light state and is changed to a concave wave by the convex lens 201. . The laser beam converted into the concave wave is converted into a plane wave by passing through the concave lens 202.

  FIG. 18C shows a state where a convex wave is converted into a plane wave. The focal position F1 of the convex lens 201 and the focal position F2 of the concave lens 202 are on the same optical axis, and the focal position F2 is disposed upstream of the focal position F1. When the convex wave laser beam is incident on the convex lens 201, it is converted into a concave wave. The concave wave laser beam is converted into a plane wave by passing through the concave lens 202.

  FIG. 18D shows an example in which the wavefront curvature corrector 200 </ b> A is configured using two convex lenses 201 and 203. The convex lens 201 can be moved in the left-right direction (optical axis direction) in FIG.

  When laser light input as a plane wave (parallel light) is output as a plane wave (parallel light), the position of the convex lens 201 is set so that the focal position of the convex lens 201 matches the focal position of the convex lens 203.

  When the laser light becomes convergent light (concave wave surface) due to the thermal load, the uniaxial stage 204 moves the convex lens 201 to the downstream position 20IR on the optical axis. Conversely, when the laser light becomes divergent light (convex wave surface), the uniaxial stage 204 moves the convex lens 201 to the upstream position 201L on the optical axis.

  A seventh embodiment will be described with reference to FIG. In this embodiment, an example in which the wavefront curvature corrector 200B is configured as a reflective optical system will be described. The wavefront curvature corrector 200B includes two reflecting mirrors 205 (1) and 205 (2) and two off-axis parabolic concave mirrors 206 (1) and 206 (2). The reflecting mirror 205 (1) and the off-axis parabolic concave mirror 206 (1) located on the upper side in FIG. 19 are attached to the plate 207. The plate 207 is movable in the vertical direction in FIG. Each mirror 205 (1), 206 (1) moves up and down together with the plate 207.

  FIG. 19A shows an arrangement in the case where laser light input as parallel light (plane wave) is output as parallel light (plane wave). In this case, the focal position of the off-axis paraboloidal concave mirror 206 (1) and the focal position of the off-axis paraboloidal concave mirror 206 (2) are made to be in a confocal state cf.

  The laser light enters the reflection mirror 205 (2) from the left side (upstream side) in FIG. 19, is reflected, and enters the other reflection mirror 205 (1). The laser beam reflected by the reflecting mirror 205 (1) enters the off-axis parabolic concave mirror 206 (1). The laser light is reflected at a reflection angle of 45 degrees by the off-axis parabolic concave mirror 206 (1) and gathers at the focal position cf. The laser beam spreads from the focal position cf, enters the off-axis parabolic concave mirror 206 (2), and is reflected at a reflection angle of 45 degrees.

  FIG. 19B shows an arrangement when laser light input as convergent light (concave wave surface) is converted into parallel light (plane wave) and output. In this case, the plate 207 is moved downward, and the focal position f of the off-axis paraboloid concave mirror 206 (1) is moved downstream on the optical axis. Thereby, the focal position of the off-axis parabolic concave mirror 206 (1) and the focal position of the off-axis parabolic concave mirror 206 (2) are matched on the optical axis.

  When laser light is input as diverging light (convex wave surface), the plate 207 is moved upward in FIG.

  In the wavefront curvature corrector 200B configured as described above, the reflecting mirror 205 (1) and the off-axis parabolic concave mirror 206 (1) are fixed to the plate 207, and both the mirrors 205 (1) and 206 (1) are fixed. Simultaneously move on the optical axis (in the vertical direction in FIG. 19). Thereby, in the present embodiment, the curvature of the wavefront can be corrected by matching the optical axis of the input light with the optical axis of the output light.

  Furthermore, since the wavefront curvature corrector 200B of the present embodiment is configured as a reflective optical system, even when the laser light passes through the wavefront curvature corrector 200B, the change in the wavefront due to heat can be reduced. Thereby, even when high-power laser light is used, the curvature of the wavefront can be corrected with high accuracy.

  An eighth embodiment will be described based on FIG. The wavefront curvature corrector 200C of the present embodiment is a reflection optical system including an off-axis parabolic concave mirror 206, an off-axis parabolic convex mirror 208, and two reflection mirrors 205 (1) and 205 (2). Composed.

  The off-axis parabolic concave mirror 206 and the reflecting mirror 205 (1) are attached to a plate 207 that can move up and down. Furthermore, the focal position of the off-axis parabolic convex mirror 208 and the focal position of the off-axis parabolic concave mirror 206 are arranged to coincide with each other at cf.

  The parallel-wavefront laser light is reflected by the off-axis parabolic convex mirror 208, enters the off-axis parabolic concave mirror 206 as divergent light, and is converted into a plane wave. The plane wave laser light is reflected and output by each of the reflection mirrors 205 (1) and 205 (2). Similar to the seventh embodiment, by moving the plate 207 up and down, the wavefront of the input laser beam can be corrected to a plane wave and output.

  Configuring this embodiment like this also achieves the same effects as the seventh embodiment. Furthermore, in this embodiment, the distance between the off-axis paraboloid mirrors can be shortened by combining the concave surface 206 of the off-axis paraboloid and the convex surface 208 of the off-axis paraboloid. Accordingly, the overall dimensions can be reduced as compared with the seventh embodiment.

  A ninth embodiment will be described with reference to FIGS. In this embodiment, the wavefront curvature correctors 200D and 200E are configured by arranging one convex mirror 209 and one concave mirror 210 in a Z shape.

  FIG. 21 shows a wavefront curvature corrector 200D configured by arranging an upstream spherical convex mirror 209 and a downstream spherical concave mirror 210 in a Z shape. For example, when divergent (convex wavefront) laser light is incident on the convex mirror 209, the convex mirror 209 reflects the laser light at a small incident angle α of about 3 degrees or less. The reflected laser light enters the concave mirror 210 at an incident angle α, is converted into parallel light (plane wave), and is output.

  For example, as indicated by an arrow in FIG. 21, the wavefront of the laser light can be converted into a plane wave by moving the position of the concave mirror 210 along the reflection optical axis of the convex mirror 209.

  FIG. 22 shows a wavefront curvature corrector 200E configured by arranging an upstream concave mirror 210 and a downstream convex mirror 209 in a Z shape. For example, when divergent light (convex wavefront) laser light is incident on the concave mirror 210, the concave mirror 210 reflects the laser light at a small incident angle α (for example, 3 degrees or less). The reflected laser light enters the convex mirror 209 at an incident angle α and is converted into parallel light (plane wave). For example, the curvature of the wavefront of the laser light can be converted into a plane wave by moving the position of the convex mirror 209 along the reflection optical axis of the concave mirror 210.

  Thus, in this embodiment, since the wavefront curvature corrector can be configured by the convex mirror 209 and the concave mirror 210, the manufacturing cost can be reduced. Further, because of the reflection optical system, it is possible to reduce the wavefront change that occurs when the laser light passes through the wavefront curvature corrector.

  In the present embodiment, the optical axis of the output laser light moves in parallel with the optical axis of the input laser light. Therefore, an optical system for matching the optical axis of the output light with the optical axis of the input light may be added to the present embodiment.

  A tenth embodiment will be described with reference to FIGS. In the present embodiment, a case will be described in which wavefront curvature correctors 200F and 200G are composed of lenses and mirrors.

  FIG. 23 shows a case where a wavefront curvature corrector 200F is constituted by the concave lens 211L and the concave mirror 211M. For example, when convergent light (concave wave surface) laser light is incident on the concave lens 211L, it is converted into divergent light (convex wave surface). The divergent laser light is incident on the concave mirror 211M and reflected as parallel light.

  Here, when the concave mirror 211M is an off-axis parabolic concave mirror, the concave mirror 211M is installed so as to have an incident angle of the off-axis parabolic concave mirror. When the concave mirror 211M is a spherical mirror, the incident angle is set to a small angle (5 degrees or less) in order to reduce the wavefront aberration. By moving the concave lens 211L along the optical axis, the wavefront of the incident laser light can be corrected.

  FIG. 24 shows a case where the wavefront curvature corrector 200G is constituted by the convex lens 212L and the convex mirror 212M. When diverging light (convex wave surface) laser light enters the convex lens 212L, the laser light becomes convergent light (concave wave surface) and enters the convex mirror 212M. The laser light is reflected as parallel light by the convex mirror 212M.

  When the convex mirror 212M is an off-axis parabolic convex mirror, the incident angle of the off-axis parabolic convex mirror is set. When the convex mirror 212M is a spherical mirror, the incident angle is set to a small angle (5 degrees or less) in order to reduce the wavefront aberration. The curvature of the wavefront of the laser light can be corrected by moving the convex lens 212L along the optical axis.

  In this embodiment configured as described above, the optical axis of the input laser beam and the optical axis of the output laser beam coincide with each other, which is advantageous compared to the ninth embodiment. Further, in this embodiment, only one lens, which is a transmission optical element, is used, so that the wavefront change due to heat can be reduced as compared with the sixth embodiment (FIG. 18) using two lenses.

  An eleventh embodiment will be described with reference to FIGS. In this embodiment, a variable mirror is used that can variably control the curvature of the reflection surface by a control signal from the wavefront correction controller 50. Such a variable mirror is called a VRWM (Variable Radius Wave front Mirror) in this embodiment.

  The wavefront curvature corrector 200H of the present embodiment is composed of VRWM. FIG. 25A and FIG. 26A show a case where laser light incident as a plane wave (parallel light) is emitted as a plane wave (parallel light). When a plane wave is converted into a plane wave, the surface of the VRWM is controlled to be flat.

  FIG. 25B shows a case in which convex (divergent) laser light is converted into plane wave (parallel light) laser light. In this case, the shape is controlled so that the VRWM is concave.

  FIG. 25C shows a case where a laser beam having a concave surface (converged light) is converted into a laser beam having a plane wave (parallel light). In this case, the shape is controlled so that VRWM becomes a convex surface.

  FIG. 26B shows a case where a plane wave is converted into a concave spherical wave. In order to convert a plane wave into a concave spherical wave, the surface of the VRWM is controlled to have a concave toroidal shape (when the incident angle is about 45 degrees). As a result, the laser light reflected by the VRWM gathers at the focal length F. The spherical wave immediately after being reflected by the toroidal VRWM surface becomes a concave spherical wave having a radius of curvature R. The focal length F is equal to the radius of curvature R of the spherical wave.

  FIG. 26C shows a case where a plane wave is converted into a convex spherical wave. In order to convert a plane wave into a convex spherical wave, the surface of the VRWM is controlled to have a convex toroidal shape (when the incident angle is about 45 degrees). The convex wave reflected by the VRWM becomes a wavefront emitted from the point light source at the position of the focal length −F. The spherical wave immediately after being reflected by the toroidal VRWM surface becomes a spherical wave having a radius of curvature −R. The focal length -F is equal to the radius of curvature -R of the wavefront.

  In this embodiment configured as described above, since the wavefront curvature corrector 200H can be configured only by VRWM, the number of components can be reduced, and the wavefront curvature corrector 200H can be formed compactly. high.

  Furthermore, the wavefront curvature corrector 200H of the present embodiment can emit the incident laser beam by changing the optical axis of the laser beam to 45 degrees. Therefore, as shown in FIG. 27, the wavefront curvature corrector 200H can be used at a position where the optical path of the laser light is changed by 45 degrees. In that case, since the reflection mirror 41 can be omitted, the configuration can be simplified and the manufacturing cost can be reduced.

  A twelfth embodiment will be described with reference to FIG. In this embodiment, the VRWM 213 and the reflection mirror 214 are arranged in a Z shape to constitute the wavefront curvature corrector 200J.

  As shown in FIG. 28A, when the laser light incident on the VRWM as a plane wave is emitted as a plane wave, the VRWM 213 is controlled to have a flat shape. As shown in FIG. 28B, when converting the laser light incident as a convex wave into a plane wave, the shape of the VRWM 213 is set to a concave spherical shape. As shown in FIG. 28C, when converting the laser light incident as a concave wave into a plane wave, the shape of the VRWM 213 is set to a convex spherical shape.

  Configuring this embodiment like this also achieves the same effects as the eleventh embodiment. However, in this embodiment, the incident optical axis and the outgoing optical axis of the laser light are shifted in parallel and do not match. Therefore, an optical system for returning the optical axis may be added to this embodiment.

  A thirteenth embodiment will be described with reference to FIG. In the present embodiment, an angle corrector 100A is constituted by one reflecting mirror 102 and one parallel plane window 103. The reflection mirror 102 and the parallel plane window 103 are rotatable in both clockwise and counterclockwise directions in FIG.

  As indicated by a solid arrow in the drawing, the laser light incident on the reflecting mirror 102 is reflected by the reflecting mirror 102, enters the window 103, passes through the window 103, and is emitted. The optical axis indicated by this solid line arrow is taken as the reference optical axis.

  On the other hand, as shown by a dotted arrow, when the laser beam is inclined and enters the reflection mirror 102, the inclination angle of the reflection mirror 102 is adjusted. Thereby, the optical axis of the laser beam reflected by the reflecting mirror 102 is made parallel to the reference optical axis.

  Laser light parallel to the reference optical axis is incident on the parallel plane window 103. By adjusting the inclination angle of the parallel plane window 103, the optical axis of the laser light transmitted through the parallel plane window 103 can be matched with the reference optical axis.

  A fourteenth embodiment will be described with reference to FIG. In this embodiment, a wavefront corrector 34A that can be used as both an angle corrector and a wavefront curvature corrector will be described. The wavefront corrector 34 </ b> A includes a VRWM 110 and a reflection mirror 111.

  FIG. 30A shows a case where the heat load is small. The plane wave laser light is incident on and reflected by the reflection mirror 111 at 45 degrees, and is incident on the VRWM 110 at an incident angle of 45 degrees. The VRWM 110 is controlled to have a flat shape. The laser light is reflected by the flat mirror surface of the VRWM 110 and output in the form of a plane wave.

  Note that the present invention is not limited to the case where plane wave incident light is converted into plane wave outgoing light. The focal length of the VRWM can also be controlled to a constant value so that laser light input as divergent light (convex wavefront) is output as laser light having a wavefront with a desired curvature.

  FIG. 30B shows a case where the angle (direction) of the laser beam and the curvature of the wavefront are changed.

  It is assumed that the direction of the incident laser beam is tilted downward in FIG. 30 due to the influence of the thermal load, and its wavefront changes to diverging light (convex wavefront). In that case, the angle of the reflection mirror 111 is controlled so that the optical axis of the laser beam reflected by the reflection mirror 111 coincides with the reference optical axis.

  The laser beam reflected by the reflection mirror 111 enters the VRWM 110 at an incident angle of 45 degrees. The shape of the VRWM 110 is set to be concave so that the laser light reflected by the VRWM 110 becomes a plane wave.

  In addition, although the case where the laser beam of a convex wave is converted into a plane wave was described, it is not restricted to this. The concave wave laser beam can be converted into a plane wave, or the incident light of the convex wave surface or the concave wave can be converted into outgoing light having a wave surface with a desired curvature.

  Further, in the case of the incident angle within the allowable aberration, for example, by controlling the biaxial angle of the VRWM 110 in the horizontal direction and the vertical direction (by controlling the tilt and roll), the optical axis of the emitted light is changed to the reference optical axis. May be matched.

  A fifteenth embodiment will be described with reference to FIG. In the present embodiment, the reflection mirror 113 and the VRWM 112 are arranged in a Z shape to constitute a wavefront corrector 34B that serves both as an angle corrector and a wavefront curvature corrector. The incident angle is a small angle of about 3 degrees or less. That is, the incident angle is set to an angle at which no aberration occurs.

  FIG. 31A shows a case where the heat load is low. The plane-wave laser light is incident on the reflection mirror 113 at an incident angle of 3 degrees or less and reflected. The reflected laser light is incident on the VRWM 112 at an angle of 3 degrees or less. The shape of the VRWM 112 is controlled to be flat and reflects the laser light in a plane wave state. Although the case of a plane wave has been described, the present invention is not limited to this. For example, even when a convex wave or a concave wave is input, by changing the shape of the VRWM 112, a laser beam having a wavefront with a predetermined curvature may be output. it can.

  FIG. 31B shows a case where the heat load is high. A case where the angle of the incident laser beam is inclined downward in FIG. 31 and the wavefront of the laser beam is a convex wave will be described. In this case, the angle of the reflection mirror 113 is changed so that the optical axis of the laser light reflected by the reflection mirror 113 matches the reference optical axis (the optical axis shown in FIG. 31A).

  The light reflected by the reflection mirror 113 enters the VRWM 112 at an incident angle of 3 degrees or less. The VRWM 112 is changed into a convex shape and the angle thereof is adjusted so that the laser light reflected by the VRWM 112 becomes a plane wave. In addition to the case of converting to a plane wave, a concave wave or a convex wave can be converted into a wavefront having a desired curvature and output. The same applies to the following embodiments.

  A sixteenth embodiment will be described with reference to FIG. In the present embodiment, by using two convex lenses 114 and 115, a wavefront corrector 34C that serves both as an angle corrector and a wavefront curvature corrector is configured. The convex lens 115 is provided on a moving stage 117 for adjusting the position in a direction (vertical direction in FIG. 32) orthogonal to the optical axis. Further, the moving stage 117 is provided on another moving stage 118 for adjusting the position in the optical axis direction. Therefore, the convex lens 115 can be moved both in the optical axis direction and in the direction orthogonal to the optical axis. Reference numeral 119 is a point (light condensing point) where light that has passed through the convex lens 114 gathers.

  FIG. 32A shows a case where the heat load is small. The plane wave laser light passes through the convex lens 114 and gathers at the focal position of the convex lens 114. The convex lens 115 is disposed so that the focal position of the convex lens 115 coincides with the focal position of the convex lens 114 on the same optical axis. The light condensed at that position becomes divergent light, enters the convex lens 115, is converted into a plane wave by the convex lens 115, and is output.

  FIG. 32B shows a case where the heat load is large. Due to the influence of the thermal load, the incident direction of the laser beam is inclined obliquely upward and becomes divergent light (convex wave surface). Therefore, the divergent light is collected farther than the focal position of the convex lens 114. Then, the position of the convex lens 114 is moved in the optical axis direction (left-right direction in FIG. 32) so that the focal point coincides with the front focal point of the convex lens 115. Furthermore, the convex lens 115 is moved in a direction (vertical direction in FIG. 32) orthogonal to the optical axis. Thereby, the emission direction of the laser beam is made to coincide with the reference optical axis. The laser light that has passed through the convex lens 114 enters the convex lens 115, is converted into a plane wave, and is output along the reference optical axis.

  Note that the wavefront corrector 34 that performs angle correction and wavefront curvature correction may be configured by combining one convex lens and one concave lens, without being limited to the combination of the convex lens 114 and the convex lens 115.

  A seventeenth embodiment will be described with reference to FIG. In the present embodiment, the deformable mirror 120 and the reflection mirror 121 are used to configure a wavefront corrector 34D that serves both as an angle corrector and a wavefront curvature corrector.

  As shown in FIG. 33, the deformable mirror 120 and the reflecting mirror 121 are arranged in a Z shape. The shape of the reflecting surface of the deformable mirror 120 is variably controlled according to the control signal. The deformable mirror 120 is disposed in front of the preamplifier or between the preamplifier and the main amplifier. As a result, laser light before becoming high-power laser light is incident on the deformable mirror 120.

  When distorted laser light with a wavefront is incident on the deformable mirror 120, the shape of the reflecting surface of the deformable mirror 120 is adjusted according to the incident wavefront. The deformable mirror 120 corrects the wavefront of the incident laser light into a plane wave and reflects it. The laser light corrected to a plane wave is reflected by the reflection mirror 121 and output.

  By using the deformable mirror 120, a wavefront that is not a spherical wave, for example, a wavefront such as an S-shape, can be converted into a plane wave or a desired spherical wave. If the angle is small, the direction of the laser beam can also be corrected. Note that the direction of the laser beam can be adjusted by controlling the tilt and roll of each of the reflection mirror 121 and the deformable mirror 120. The same applies to Example 18.

In the present embodiment, the deformable mirror 120 is arranged in front (upstream side) of the main amplifier, so that it is possible to correct the wavefront of the relatively low output laser light. On the other hand, in the technique described in Japanese Patent Application Laid-Open No. 2003-270551 described above, since the high-power laser light is incident on the deformable mirror, the deformable mirror is highly likely to be damaged by the heat of the laser light. Low reliability. The deformable mirror is configured as an assembly of a large number of microactuators, and it is difficult to effectively cool the deformable mirror. Therefore, when high-power laser light is incident on the deformable mirror, there is a high possibility that the deformable mirror is damaged by heat.

  The eighteenth embodiment will be described with reference to FIG. In this embodiment, the wavefront corrector 34E is configured by combining the deformable mirror 120 and polarization control. The wavefront corrector 34E includes a deformable mirror 120, a beam splitter 122, and a λ / 4 plate 123. Wavefront change generators 32, 35, and 33 can be disposed between the beam splitter 122 and the λ / 4 plate 123.

  For example, laser light of P-polarized light (polarization plane including paper) enters the beam splitter 122 provided with a film for separating P-polarized light and S-polarized light. It is assumed that the wavefront of the laser light is input to the beam splitter 122 in a plane wave state. However, it is assumed that the laser beam passes through the wavefront change generators 32, 35, and 33 from the beam splitter 122, and the wavefront is distorted in an S shape.

  The laser light that has passed through the wavefront change generators 32, 33, and 35 passes through the λ / 4 plate 123 and becomes circularly polarized light. The wavefront distorted in an S shape is corrected to a predetermined wavefront by the deformable mirror 120 adjusted to an appropriate shape.

  The laser beam whose wavefront is corrected passes through the λ / 4 plate 123 again and is converted to S-polarized light. The S-polarized laser light is converted from a predetermined wavefront into a plane wave by passing through the wavefront change generators 32, 33, and 35. The laser light converted into a plane wave enters the beam splitter 122. The S-polarized laser light is reflected by the beam splitter 122 and output as a plane wave. By adjusting the surface shape of the deformable mirror 122, a wavefront shape other than a plane wave can be output.

  A nineteenth embodiment will be described with reference to FIG. In the present embodiment, the sensor 36 </ b> A is configured using the diffractive mirror 301. A grating 301 </ b> A is formed on the surface of the diffractive mirror 301. The diffractive mirror 301 is provided with a cooling water passage 301 </ b> B through which cooling water flows.

  The diffractive mirror 301 reflects incident laser light at an angle of 45 degrees. This reflected light is zero-order light and has the highest intensity. The minus first-order light obtained by diffraction has a low intensity. The optical sensor unit 360 receives the −1st order light and measures the characteristics of the laser light.

  A twentieth embodiment will be described with reference to FIG. In the present embodiment, the sensor 36B is configured using the window 300W. The window 300W includes a window substrate 300AW and a holder 300BW for holding the window substrate 300AW. Holder 300BW includes a water cooling jacket (not shown).

  The window 300W is disposed in an inclined state in the optical axis of the driver laser beam. The slight laser light reflected by the surface of the window 300W enters the optical sensor unit 360 as sample light.

  As the window 300W, for example, the windows of the amplifiers 32 and 35 and the window 13 of the EUV chamber 10 can be used. In this case, it is not necessary to provide a window just to obtain sample light for measurement, and the manufacturing cost can be reduced. The window substrate 300A is made of a material that transmits CO2 laser light such as diamond and has high thermal conductivity.

  In the parallel plane window 300W, the laser light is slightly reflected by both the front surface and the back surface, and enters the optical sensor unit 360 as sample light. Therefore, it is not suitable for measuring a beam profile. However, it is possible to collect the sample light at the focal position with the condenser lens, measure the position of the focus image, and measure the direction of the laser light. Also, the duty and power of the laser beam line can be measured without any inconvenience.

  A twenty-first embodiment will be described with reference to FIG. In the present embodiment, the sensor 36C is configured by using the beam profilers 304A and 304B. In this embodiment, the light transmitted through the reflection mirror 302A is detected by the beam profiler 304A, and the light transmitted through the reflection mirror 302B is detected by the beam profiler 304B. The angle of the reflection mirror 302A is adjusted according to the measurement result of the beam profiler.

  A lens 303A is provided between the back side of the reflection mirror 302A and the beam profiler 304A. Similarly, a lens 303B is provided between the back side of the reflection mirror 302B and the beam profiler 304B.

  The plane-wave laser light is transmitted through the relay optical system 31 and transmitted through the wavefront change generators 32, 35, and 33, whereby the direction of the laser light and the curvature of the wavefront are changed. The laser light whose direction and the curvature of the wavefront are changed enters the wavefront corrector 34. The wavefront corrector 34 corrects the curvature of the wavefront and the direction of the laser beam, and outputs the laser beam.

  The laser light corrected by the wavefront corrector 34 is reflected by the reflection mirror 302A and enters the reflection mirror 302B. On the other hand, the sample light slightly transmitted through the reflecting mirror 302A is transferred onto the two-dimensional sensor of the beam profiler 304A by the transfer lens 303A. The two-dimensional sensor measures the beam shape and position of the laser light.

  Measurement data from the beam profiler 304 </ b> A is input to the wavefront correction controller 50. The wavefront correction controller 50 controls the wavefront corrector 34 by transmitting a control signal so that the position of the laser beam becomes the reference position.

  On the other hand, the light slightly transmitted through the reflection mirror 302B is transferred onto the two-dimensional sensor provided in the beam profiler 304B by the transfer lens 303B. The two-dimensional sensor measures the beam shape and position of laser light.

  The data measured by the beam profiler 304B is input to the wavefront correction controller 50. The wavefront correction controller 50 outputs a control signal to the actuator 305 for adjusting the angle of the reflection mirror 302A, and controls the angle of the reflection mirror 302A so that the position of the laser beam measured by the beam profiler 304B becomes the reference position. To do. Further, in order to control the curvature of the wavefront of the laser light, a control signal is sent to the WFC 34 so that the laser beam shape becomes a predetermined value.

  In this embodiment configured as described above, the beam profilers 304A and 304B are disposed on the side where the laser light is transmitted through the reflection mirrors 302A and 302B (the back side of the reflection mirror), so that the sensor 36C can be configured in a compact manner. . Further, the measurement optical system shown in FIG. 37 can reduce the influence of the wavefront of the driver laser light.

  A twenty-second embodiment will be described with reference to FIG. In this embodiment, a change that occurs in the direction of the laser beam and the curvature of the wavefront is predicted based on the temperature change of the optical element through which the laser beam passes.

  The measurement optical element 310 is a window, a lens, or a mirror through which laser light is transmitted. The optical element 310 is attached to the holder 311. The holder 311 is provided with a flow path 311A through which cooling water flows.

  On the cooling water inflow side, for example, a temperature sensor 312 (1) such as a platinum resistance temperature detector or a thermistor is provided. The temperature sensor 312 (1) detects the temperature of the cooling water and outputs a signal. A temperature sensor 312 (2) is also provided on the downstream side of the cooling water.

  The water temperature difference calculation unit 313 calculates a difference between the upstream cooling water temperature and the downstream cooling water temperature, and outputs the difference to the laser beam characteristic determination unit 314. The water temperature difference is proportional to the amount of heat Q used to cool the optical element 310 if the flow rate of the cooling water is constant.

  The laser beam characteristic determination unit 314 uses a table 315 indicating the relationship between the water temperature difference and the direction of the laser beam and a table 316 indicating the relationship between the water temperature difference and the curvature of the wavefront to transmit the laser light that passes through the optical element 310. And predict the wavefront curvature. The prediction result is input to the wavefront correction controller 50.

  The table 315 is generated, for example, by measuring in advance a change in the direction of the laser beam due to a difference in water temperature by experiment or simulation. Similarly, the table 316 is generated by measuring in advance the change in the curvature of the wavefront due to the water temperature difference through experiments and simulations.

  According to the present embodiment, by detecting the temperature change of the optical element 310 as a difference in the cooling water temperature, the wavefront change (angle (direction) and wavefront curvature) of the laser light can be easily estimated. In addition, the structure which measures the temperature change of the optical element 310 directly using a radiation thermometer may be sufficient.

  A twenty-third embodiment will be described with reference to FIG. In this embodiment, the temperature of the optical element 310 is directly detected by the temperature sensor 312A. The temperature sensor 312A is covered with a light shielding plate 317 for protection from laser light.

  The laser beam characteristic determination unit 314A refers to the tables 315A and 316A based on the temperature detected by the temperature sensor 312A, thereby predicting the change in the direction of the laser light passing through the optical element 310 and the curvature of the wavefront.

  In the table 315A, for example, the relationship between the temperature of the optical element 310 and the direction of the laser beam is set in advance by experiment or simulation. Similarly, the relationship between the temperature of the optical element 310 and the curvature of the wavefront of the laser beam is set in advance in the table 316A through experiments and simulations.

  A twenty-fourth embodiment will be described with reference to FIG. In this embodiment, based on the operation instruction from the EUV light exposure apparatus 5, the influence of the thermal load generated on the driver laser light is predicted, and the wavefront correction is performed so as to cancel the predicted influence of the thermal load.

  The EUV exposure apparatus 5 gives an operation instruction to the EUV light source controller 70. The driving instruction includes, for example, pulse energy Eeuv of EUV light and a repetition frequency f (or an external trigger signal). The EUV light source controller 70 outputs a control signal to the laser controller 60 in order to supply the EUV light required by the EUV exposure apparatus 5.

  For example, it is assumed that a proportional relationship of Eco2 = K · Eeuv is established between the EUV energy Eeuuv and the driver laser energy Eco2 (however, since it is actually a non-linear relationship, the relationship between Eeuv and Eco2 is It is preferable to find it in an experiment and store it in a table.) If the above assumption holds, the thermal load Wlaser of the driver laser beam can be expressed as Wlaser = duty · K · Eeuv · f.

  The wavefront correction controller 50A includes a prediction unit 36F and a wavefront control unit 50A1. The prediction unit 36F predicts a wavefront change that occurs in the laser light instead of the sensor 36. The wavefront controller 50A1 controls the wavefront corrector 34 based on the predicted wavefront change.

  The prediction unit 36F includes, for example, a driving instruction acquisition unit 320 that acquires a driving instruction, a laser beam characteristic determination unit 321, a table 322 that indicates the relationship between the driving state and the direction of the laser light, and the wave front of the driving state and the laser light. And a table 323 showing the relationship with the curvature of the.

  The laser beam characteristic determination unit 321 predicts a wavefront change in the laser light by referring to the tables 322 and 323 based on the operation instruction from the EUV exposure apparatus 5. The wavefront control unit 50A1 controls the wavefront corrector 34 so as to cancel the predicted wavefront change.

  A twenty-fifth embodiment will be described with reference to FIG. In the present embodiment, the actual focused image of the driver laser light in the EUV chamber 10B is measured, and the wavefront corrector 44 is controlled.

  A sensor 45A is provided in the EUV light emission region 11 (2) of the chamber 10B. The sensor 45A includes, for example, a beam splitter 330, transfer lenses 331 and 332, and an imaging unit 333. The imaging unit 333 is configured by an element such as an infrared CCD (Charge Coupled Device), for example.

  The beam splitter 330 reflects part of the driver laser light condensed at a predetermined position toward the transfer lenses 331 and 332. The remaining driver laser light is absorbed by the damper 19 and converted into heat.

  The wavefront correction controller 50B outputs a control signal to the wavefront corrector 44 so that the shape and position of the laser light condensed in the chamber 10B become a predetermined shape and position.

  The wavefront of the driver laser beam is not corrected only by the wavefront corrector 44, but the positions and postures of the mirrors 16 (1), 16 (2), 17, and 18 in the light collection region 11 (1) are adjusted. By doing so, the wavefront of the driver laser light may be corrected.

  In the present embodiment, the final focusing result of the driver laser beam is measured and the wavefront of the driver laser beam is controlled, so that the focusing property can be stabilized with high accuracy.

  A twenty-sixth embodiment will be described with reference to FIG. In this embodiment, a Shack-Hartmann sensor is used as the optical sensor unit 360A. The Shack-Hartmann sensor 360A includes, for example, a microlens array 361 composed of a large number of microlenses and an image sensor 362 such as an infrared CCD.

  Most of the laser light is reflected by the reflection mirror 300. Laser light that slightly passes through the reflection mirror 300 enters the microlens array 361. The image of the condensing point of each microlens is measured by the imaging unit 362. By analyzing the position of the condensing point of each microlens, the wavefront of the laser beam can be measured.

  In the present embodiment, it is possible to simultaneously measure the distortion and angle (direction) of the wavefront of the laser beam. Note that a pinhole array, a Fresnel lens array, or the like may be used instead of the microlens array.

  A twenty-seventh embodiment will be described with reference to FIGS. In this embodiment, the characteristics of the laser beam are measured based on the interference fringes obtained by the wedge substrate 363. The optical sensor unit 360 </ b> B includes a wedge substrate 363 and an infrared sensor 364. The wedge substrate 363 transmits the carbon dioxide laser.

  Most of the laser light is reflected by the reflection mirror 300. The laser light slightly transmitted through the reflection mirror 300 enters the wedge substrate 363 and is reflected on both the front and back surfaces of the wedge substrate 363.

  Interference fringes are generated by superimposing the laser beams reflected on the front and back surfaces of the wedge substrate 363 at a predetermined angle. FIG. 44A shows interference fringes when the laser light incident on the wedge substrate 363 is a plane wave. FIG. 44B shows interference fringes when the laser light incident on the wedge substrate 363 is a convex wave. FIG. 44C shows interference fringes when the laser light incident on the wedge substrate 363 is a concave surface wave.

  Interference fringes obtained by the wedge substrate 363 are detected by the infrared sensor 364. Based on the bending state of the interference fringes, it is possible to detect a change in the curvature of the wavefront of the laser light. Furthermore, the direction of the laser light can be detected based on the direction in which the interference fringes flow.

  In this embodiment, the distortion and direction of the wavefront of the laser beam can be measured simultaneously. However, it is difficult to expect as high accuracy as the Shack-Hartmann sensor. Instead of the infrared sensor 364, a beam profile, beam pointing, energy meter, or the like may be used.

  The twenty-eighth embodiment will be described with reference to FIG. The optical sensor unit 360C of the present embodiment measures the beam profile and beam pointing.

  The laser light transmitted through the reflection mirror 300 is split into reflected light and transmitted light by the beam splitter 363A. The transmitted light is condensed on the two-dimensional infrared sensor 366 (1) by the condensing lens 365 (1), and the condensing performance and direction (pointing state) are measured. On the other hand, the reflected light is transferred and imaged on the two-dimensional infrared sensor 366 (2) by the transfer lens 365 (2), and the beam profile is measured.

  A twenty-ninth embodiment will be described with reference to FIGS. In this embodiment, the optical sensor unit 360D is configured by using a cylindrical lens 367 having a cylindrical convex surface, a cylindrical lens 368 having a cylindrical convex surface, and a four-divided light receiving element 369. Here, the bus lines of both cylindrical lenses are arranged so as to be orthogonal to each other. The definition of the bus will be described later.

  As shown in FIG. 47, the light receiving surface 369A of the light receiving element 369 is divided into four regions of diamond-shaped DA1 to DA4. The outputs of the upper and lower light receiving surfaces DA1, DA3 and the outputs of the left and right light receiving surfaces DA2, DA4 arranged orthogonal to DA1, DA3 are compared and output by the operational amplifier 369B.

  As shown in FIG. 48A, when the convex-wave laser light passes through the lenses 367 and 368, it becomes long laser light in the vertical direction and enters the light receiving element 369. The light receiving element 369 outputs a positive voltage.

  As shown in FIG. 48C, when the concave wave surface laser light passes through the lenses 367 and 368, the laser light becomes long in the horizontal direction and enters the light receiving element 369. The light receiving element 369 outputs a negative voltage.

  On the other hand, as shown in FIG. 48B, when plane-wave laser light is transmitted through the lenses 367 and 368, the light is incident on the light receiving element 369 as substantially circular laser light. The output of the light receiving element 369 is zero. Note that a two-dimensional sensor may be used instead of the light receiving element 369.

  A thirtieth embodiment will be described with reference to FIGS. The optical sensor unit 360E of the present embodiment has two cylindrical lenses 368 (1) and 368 (2) having the same focal length and are arranged on the optical axis of the laser beam by making the generating lines of the cylindrical lenses orthogonal to each other. Deploy. The generating line of the cylindrical lens is a line connecting the tops of the convex surfaces. Each cylindrical lens 368 (1) and 368 (2) is configured as a cylindrical convex cylindrical lens.

  The light receiving element is disposed at an intermediate position D between the focal length F1 of the cylindrical lens 368 (1) and the focal length F2 of the cylindrical lens 368 (2). As the light receiving element, a quadrant light receiving element shown in FIG. 47, a two-dimensional imaging element, or the like can be used. Hereinafter, the position D where the light receiving element is disposed is referred to as a sensor position D.

  FIG. 49A shows a case where the plane-wave laser light is viewed from the horizontal direction (X) and the vertical direction (Y) when the two cylindrical lenses 368 (1) and 368 (2) are transmitted. The condensing state of the laser beam is shown.

  49A, the bus line of the first cylindrical lens 368 (1) is perpendicular to the horizontal direction (X direction), and the bus line of the second cylindrical lens 368 (2) is horizontal (X ) Shows the state of the laser beam when it is parallel. In this case, with respect to the X direction, the first cylindrical lens 368 (1) functions as a convex lens, and the second cylindrical lens 368 (2) functions as a window.

  Accordingly, at the focal position F1 of the cylindrical lens 368 (1), the laser light is condensed in a linear shape parallel to a direction perpendicular to the X direction and then spreads as divergent light. At the sensor position D indicated by the dotted line, the laser beam spreads to a certain length L1 parallel to the X axis.

  On the lower side of FIG. 49A, the bus of the first cylindrical lens 368 (1) is parallel to the vertical direction (Y), and the bus of the second cylindrical lens 368 (2) is vertical (Y The state of the laser beam is shown in the case perpendicular to (). In this case, with respect to the Y direction, the first cylindrical lens 368 (1) functions as a window, and the second cylindrical lens 368 (2) functions as a convex lens.

  Accordingly, the laser beam is condensed linearly at the focal position F2 of the cylindrical lens 368 (2) in parallel with the direction orthogonal to the Y direction. Since the sensor position D is in front of the focal position F2, laser light having a certain length L2 parallel to the Y axis is detected.

  FIG. 49B shows the shape IM1 of the laser light measured at the sensor position D on the XY plane. The cross-sectional shape IM1 on the XY plane of the laser light is a substantially rectangular shape having a width L1 in the X direction and a width L2 in the Y direction. If F1 = F2 is set and the sensor position D is arranged at the center of each of the cylindrical 368 (1) and 368 (2), a square shape of L1 = L2 is obtained.

  FIG. 50 shows a condensing state of the laser light when the convex-wave laser light is transmitted through the two cylindrical lenses 368 (1) and 368 (2). The upper side of FIG. 50A corresponds to the upper side of FIG. The lower side of FIG. 50A corresponds to the lower side of FIG. Similarly, FIG. 51 corresponds to FIG.

  As shown in the upper side of FIG. 50A, the convex-wave laser light is slightly far from the focal position F1 of the cylindrical lens 368 (1) (on the right side in FIG. 50) and parallel to the direction orthogonal to the X direction. In addition, the light is condensed linearly. Laser light spreads as diverging light. At the sensor position D, the laser beam spreads to a certain length L1a parallel to the X axis.

  As shown in the lower side of FIG. 50 (a), the convex wave laser beam is condensed linearly in parallel with the direction orthogonal to the Y direction at a position farther than the focal position F2 of the cylindrical lens 368 (2). To do. Since the sensor position D is in front of the condensing point, the laser light has a certain length L2a parallel to the Y axis.

  FIG. 50B shows a shape IM2 of the convex-wave laser light in the XY plane. The shape IM2 of the laser beam is a rectangular shape having a width L1a in the X direction and a width L2a in the Y direction and long in the Y direction.

  FIG. 51 shows a state of the laser light when the concave wave laser light is transmitted through each of the cylindrical lenses 368 (1) and 368 (2). As shown in the upper side of FIG. 51 (a), the laser beam is condensed linearly in parallel with the direction orthogonal to the X direction before the focal position F1 of the cylindrical lens 368 (1). After focusing, the laser beam spreads as diverging light. At the sensor position D, the laser beam has a certain length L1b parallel to the X axis.

  As shown in the lower side of FIG. 51 (a), the laser beam is condensed at a position before the focal position F2 of the cylindrical lens 368 (2), and is linearly parallel to the direction orthogonal to the Y direction. Condensate. Since the sensor position D is in front of the focal point, the laser beam has a certain length L2b parallel to the Y axis.

  FIG. 51B shows the shape IM3 of the concave wave laser beam in the XY plane. The shape IM3 of the laser beam is a rectangular shape having a width L1b in the X direction and a width L2b in the Y direction and long in the X direction.

  A thirty-first embodiment will be described with reference to FIG. In this embodiment, another example of the polarization separation type isolator 46A is shown.

  The laser light is incident on the beam splitter 464 for separating P-polarized light and S-polarized light as P-polarized light. The beam splitter 464 transmits P-polarized light and reflects S-polarized light. The laser light transmitted through the beam splitter 464 is converted into circularly polarized light by transmitting through the λ / 4 plate 465.

  The laser beam is condensed and irradiated onto the droplet through an optical system in the condensing region 11 (1) provided with an optical system for condensing the laser beam. A part of the laser light returns in the same optical path as circularly polarized light and enters the λ / 4 plate 465 again. When the laser beam passes through the λ / 4 plate 465, it is converted into S-polarized light. Accordingly, the S-polarized laser light is reflected by the beam splitter 464 and absorbed by the damper 466.

  In addition, this invention is not limited to each Example mentioned above. A person skilled in the art can make various additions and changes within the scope of the present invention. Moreover, the structure which combined each above-mentioned Example suitably is also contained in the scope of the present invention.

  FIG. 53 shows an example of a preferred combination of the above embodiments. The present invention is not limited to the combination example shown in FIG. Other combinations not explicitly shown in FIG. 53 are also included in the scope of the present invention.

  A driver laser system that supplies laser light to an EUV light source device includes a “driver laser light line” and a “beam delivery + condensing optical system”. The “driver laser beam line” is a mechanism for correcting the wavefront of the beam line from the oscillator 20 of the driver laser to the main amplifier 35 at the final stage. The “beam delivery + condensing optical system” is a mechanism that delivers driver laser light to the window of the EUV chamber and irradiates a target material such as a droplet with a laser beam by the condensing optical system.

  Wavefront changes that occur in the “driver laser beam line” are broadly classified into wavefront changes caused by transmission through the amplifiers 32 and 35 and wavefront changes caused when the signal passes through the SA 33. In the condensing optical system, the condensing performance is changed by changing various optical elements such as a reflecting mirror, an isolator, and an EUV window by heat.

  FIG. 53 shows an example for correcting the wavefront change due to the amplifier transmission, the wavefront change due to the transmission through the saturable absorption cell, and the wavefront change due to the transmission through the condensing optical system.

  In the first case, in order to correct the wavefront change due to the amplifier, a wavefront corrector is configured from the reflective flat mirror and the VRWM having an incident angle of 45 degrees (FIG. 30). Further, two beam profilers having different arrangement positions are arranged as sensors (FIG. 37). In the first case, in order to correct the wavefront change of the saturable absorber, a wavefront corrector is composed of a reflective flat mirror and an incident angle of 45 degrees VRWM (FIG. 30), and the sensor of FIG. 37 is used.

  In the “beam delivery + condensing optical system” of the first case, the configuration shown in FIG. 31 is adopted as the wavefront corrector, and the configuration of the pointing sensor and the beam profiler described in FIG. 45 is adopted as the sensor. As the isolator, the configuration shown in FIG. 13 is adopted. The condensing optical system in the chamber employs the configuration shown in FIG.

  In the first case, a plurality of wavefront correctors positioned on the driver laser light line are configured by a reflection optical system, and the condensing optical system is also a simple configuration of the reflection optical system. Therefore, the wavefront change due to heat can be reduced as compared with the case where the transmission optical system is employed. Furthermore, since a simple beam profiler or pointing sensor is used as the sensor, it can be sufficiently detected even at a wavelength of 10.6 μm such as a CO2 laser.

  The second case will be described. The configurations of the wavefront corrector and sensor for correcting the wavefront change of the amplifier are the same as those in the first case (FIGS. 30 and 37). A deformable mirror is used as a wavefront corrector for correcting a wavefront change caused by the saturable absorber (FIGS. 33 and 34). Furthermore, a wavefront sensor shown in FIG. 42 is employed as the sensor. Thereby, the wavefront changed into a complicated wavefront shape by the heat load can be corrected to a precise wavefront by the deformable mirror. The wavefront sensor can accurately measure the wavefront of the laser light.

  In the “beam delivery + condensing optical system” of the second case, a structure (FIG. 19 or FIG. 20) in which an off-axis paraboloidal mirror is combined is adopted as a wavefront corrector. The sensor uses the wavefront sensor shown in FIG. The isolator employs the configuration shown in FIG.

  In the second case, distortion of the wavefront due to the saturable absorber can be corrected with high accuracy. Furthermore, since the wavefront sensor shown in FIG. 42 is adopted as the “beam delivery + condensing optical system” sensor, it is possible to irradiate the target with laser light while detecting the condensing performance on the target (droplet), and EUV The output energy of light can be further stabilized.

  A third case will be described. The configuration shown in FIG. 31 is adopted for the wavefront corrector for correcting the wavefront change of the amplifier, and the configuration shown in FIG. 46 is adopted for the sensor. The wavefront corrector and sensor of the saturable absorber are the same as in the second case.

  In the “beam delivery + condensing optical system” of the third case, the configuration shown in FIGS. 33 and 34 is used as the wavefront corrector, and the wavefront sensor shown in FIG. 42 is used as the sensor. The isolator and the condensing optical system are the same as those in the first case and the second case.

  In the third case, wavefront distortion due to the saturable absorber can be corrected with high accuracy. Furthermore, a deformable mirror is used as a wavefront corrector for the “beam delivery + condensing optical system”, and a wavefront sensor is used as a sensor. Can be irradiated with laser light. Therefore, the stability of the output energy of EUV light can be improved compared to the second case.

  The thirty-second embodiment will be described with reference to FIG. In this embodiment, a configuration of a prepulse laser and a configuration for correcting optical characteristics of the prepulse laser are added to the configuration shown in FIG. The pre-pulse laser beam L4 is applied to the droplet DP when the droplet DP reaches a predetermined position. Thereby, the target material expands. Accordingly, the density of the target material can be reduced to an appropriate value at a predetermined position where the driver laser light L1 is irradiated, and the generation efficiency of EUV light can be increased.

  Therefore, in this embodiment, a prepulse laser oscillator 90 and an off-axis parabolic concave mirror 92 for sending the prepulse laser beam into the chamber 10 through the window 13 (2) are provided. As the prepulse laser light, for example, a fundamental wave, a second harmonic, a third harmonic, and a fourth harmonic of a YAG laser can be used. Alternatively, the fundamental wave or harmonic light of a pulsed titanium sapphire laser may be used as the prepulse laser light. In this embodiment, the target material supply unit that supplies the droplet DP is not shown, but for example, the droplet DP is supplied to the position of the prepulse laser focusing point on an axis perpendicular to the paper surface.

  Since the diameter of the tin droplet DP is 100 μm or less, in order to hit the pre-pulse laser beam, it is necessary to manage the beam shape and the focusing position with high accuracy. Therefore, in this embodiment, as described in each of the embodiments, a mechanism for automatically correcting the optical performance of the pre-pulse laser beam L4 is provided. Here, the optical performance means, for example, a light condensing shape or position or pointing.

  Between the pre-pulse laser oscillator 90 and the off-axis parabolic concave mirror 92, a wavefront correction unit 95 as a “third correction unit” is provided. Between the off-axis parabolic concave mirror 92 and the window 13 (2), a sensor 96 as a “third detection unit” is provided.

  The pre-pulse laser beam L4 enters the off-axis parabolic concave mirror 92 via the wavefront correction unit 95 and is reflected toward the window 13 (2). The sensor 96 detects the optical performance of the pre-pulse laser beam L 4 that travels to the chamber 10 and outputs it to the wavefront correction controller 97. Then, the wavefront correction controller 97 controls the wavefront correction unit 95 so that the optical performance of the pre-pulse laser beam L4 becomes a predetermined value.

  In the present example configured as described above, the target material is irradiated with the pre-pulse laser beam L4 before the driver laser beam L1 is applied to the target material. Than can be raised. Furthermore, in this embodiment, the curvature and direction of the wavefront of the prepulse laser light can be adjusted, so that the target material can be irradiated with the prepulse laser light more accurately, and the efficiency can be improved.

  A thirty-third embodiment will be described with reference to FIG. In this embodiment, the prepulse laser light is amplified by a plurality of amplifiers 98 (1) and 98 (2) and then sent into the chamber 10.

  The prepulse laser beam output from the prepulse laser oscillator 90 is incident on the first amplifier 98 (1) via the first wavefront correction unit 95 (1) and is amplified. The amplified prepulse laser light passes through the first sensor 96 (1), enters the reflection mirror 91 (1), and is reflected. The first wavefront correction controller 97 (1) operates the wavefront correction unit 95 (1) based on the detection signal from the sensor 96 (1) provided on the outlet side of the amplifier 98 (1). Thereby, the wavefront shape and direction of the pre-pulse laser beam passing through the amplifier 98 (1) are adjusted to a desired value.

  The pre-pulse laser beam reflected by the reflection mirror 91 (1) enters the other reflection mirror 91 (2) via the second wavefront correction unit 95 (2), and is reflected by the reflection mirror 91 (2). The The prepulse laser beam reflected by the reflection mirror 91 (2) passes through the second amplifier 98 (2) and is further amplified. The second wavefront correction controller 97 (2) operates the wavefront correction unit 95 (2) based on the detection signal from the sensor 96 (2) provided on the outlet side of the amplifier 98 (2). Thereby, the wavefront shape and direction of the pre-pulse laser beam passing through the amplifier 98 (2) are adjusted to a desired value.

  The pre-pulse laser beam amplified by the amplifier 98 (2) passes through the second sensor 96 (2) and enters the third wavefront correction unit 95 (3). The pre-pulse laser beam that has passed through the wavefront correction unit 95 (3) is incident on the off-axis parabolic concave mirror 92 and reflected, passes through the window 13 (2), and is irradiated onto the target material in the chamber 10. The third wavefront correction controller 97 (3) operates the wavefront correction unit 95 (3) based on the detection signal from the sensor 96 (3) provided on the incident side of the window 13 (2). Thereby, the wavefront shape and direction of the pre-pulse laser beam incident on the chamber 10 are adjusted to a desired value.

  The prepulse laser controller 99 operates the prepulse laser oscillator 90 based on an instruction from the laser controller 70. Further, the prepulse laser controller 99 controls the wavefront correction controllers 97 (1) to 97 (3) to correct the wavefront and angle of the prepulse laser light. When the wavefront correction of the pre-pulse laser beam is completed, the pre-pulse laser controller 99 notifies the laser controller 70 to that effect.

  Configuring this embodiment like this also achieves the same effects as the thirty-second embodiment. Furthermore, in this embodiment, the prepulse laser light is amplified in multiple stages using a plurality of amplifiers 98 (1) and 98 (2), so that a higher output prepulse laser light can be obtained.

  When a plurality of amplifiers 98 (1) and 98 (2) are used, an error occurs in the wavefront and position or direction of the prepulse laser beam due to distortion of the optical system due to heat. However, in this embodiment, the prepulse laser beam is corrected at a plurality of locations by using a plurality of wavefront correction units 95 (1) to 95 (3) and a plurality of sensors 96 (1) to 96 (3). be able to. Therefore, in this embodiment, the target material can be irradiated with a relatively high-power prepulse laser beam accurately and stably, and the reliability and output efficiency are improved.

  A thirty-fourth embodiment will be described with reference to FIG. In this embodiment, a case where a laser light source device unique to the present invention is applied to the vapor deposition apparatus 500 will be described.

  FIG. 56 is an overall configuration diagram of the vacuum vapor deposition apparatus 500. The vapor deposition apparatus 500 includes the laser light source device 2 described above. The deposition chamber 510 includes a window 511. In the vapor deposition chamber 510, a target material 520, a substrate installation plate 530, and a substrate 540 to be vapor deposited are provided.

  The drive laser light output from the laser light source device 2 passes through the window 511 and enters the target material 520 to cause ablation 521. A portion of the ablated target material adheres to the surface of the substrate 540 placed on the plate 530.

  As described above, the laser light source device of the present invention can be applied not only to the extreme ultraviolet light source device but also to the vacuum vapor deposition device 500. Furthermore, for example, it can be applied to drilling processing or glass processing using ablation.

  A thirty-fifth embodiment will be described with reference to FIGS. In each of the following embodiments including this embodiment, a function for cooling the mirror surface axially symmetrically on a mirror 600 for making a laser beam incident on an optical element (for example, VRWM200H) for correcting a wavefront curvature. Is provided. It should be noted that the cooling function described in this embodiment can be provided not only on the mirror that causes laser light to enter the VRWM but also on other mirrors.

  FIG. 57 is a schematic diagram showing the relationship between the VRWM 200H and a mirror with cooling function (hereinafter abbreviated as mirror) 600. The mirror 600 reflects the incident laser beam L1 (1). The reflected laser beam L1 (2) enters the VRWM 200H and is reflected as the laser beam L1 (3).

Heat from the laser beam L1 (1) is transmitted to the mirror 600. Therefore, unless any countermeasure is taken, the mirror surface 602 is irregularly deformed due to thermal expansion or the like. When the mirror surface 602 is irregularly deformed, the wavefront of the laser beam L1 (2) reflected by the mirror surface 602 also has an irregular shape. The irregular wavefront shape is a shape that is neither a plane wave nor a concave wave or a convex wave, that is, a shape that is not axially symmetric with respect to the optical axis.

When the wavefront of the laser beam L1 (2) reflected by the mirror 600 has a shape that is not axially symmetric, the VRWM 200H cannot arrange the wavefront of the laser beam L1 (2) into a plane wave. This is because the VRWM 200H can deal only with a concave wave or a convex wave symmetrical to the optical axis, unlike a deformable mirror that can deal with various wavefront shapes.

  Therefore, in this embodiment, the mirror 600 is provided with a function of cooling the mirror surface 602 in an axisymmetric manner so that the mirror surface is deformed into an axisymmetric shape even when the mirror surface is deformed by heat. Thus, when the plane wave laser beam L1 (1) is incident on the mirror 600, the wavefront of the laser beam L1 (2) reflected by the mirror 600 has a convex shape, for example. The VRWM 200H reflects the convex-wave laser beam L1 (2) so as to be a plane wave.

  The cooling structure of the mirror 600 will be described with reference to the rear view of the mirror in FIG. The mirror main body 601 is formed in a disk shape from a metal material having high thermal conductivity. A reflection surface 602 for reflecting the laser beam is formed on one surface of the mirror body 601.

  A spiral cooling passage 604 is formed in the mirror main body 601 and spreads outward from the center. One end of the cooling passage 604 communicates with an inflow port 605 that opens at the center of the back surface 603 of the mirror 600. The other end side of the cooling passage 604 communicates with an outlet 606 that opens on the outer peripheral side of the back surface 603.

  FIG. 59 is a cross-sectional view of the mirror 600. A cooling pump 610 is connected to the inflow port 605. A cooler 611 is connected to the outflow port 606. A coolant such as water cooled by the cooler 611 is discharged from the pump 610 toward the inflow port 605. The refrigerant flowing into the center of the mirror 600 cools the mirror surface 602 while flowing from the center toward the outside. As a result, the center part of the mirror surface 602 is cooled most. The refrigerant flows in a spiral shape to cool the mirror surface 602 so that the temperature of the mirror surface 602 is axisymmetrically distributed. In addition, although the case where water is used as a refrigerant | coolant is mentioned as an example, you may use substances other than water. The auxiliary components such as the refrigerant tank and the filter are not shown.

  In this embodiment configured as described above, a cooling function is provided in the mirror 600 that causes laser light to enter the element 200H for correcting the wavefront, and cooling is performed so that the temperature distribution of the mirror surface 602 is axisymmetric. Therefore, even when the mirror surface 602 is deformed by heat, the mirror surface 602 can be deformed in an axial symmetry, and the wavefront can be corrected by the VRWM 200H.

  A thirty-sixth embodiment will be described with reference to FIGS. FIG. 60 is a rear view of the mirror 600A according to the present embodiment. In the mirror body 601, a plurality of annular cooling passages 604 (1) to 604 (5) are concentrically arranged.

  FIG. 61 is a cross-sectional view of the mirror 600A. In each of the annular cooling passages 604 (1) to 604 (5), an inflow port and an outflow port are provided apart from each other in the diameter direction. Each inflow port is connected to the discharge port of the pump 610 through a common inflow passage 607. Each outlet is connected to the inlet of the cooler 611 via a common outlet passage 608.

  The temperature of the surface 602 of the mirror 600A is detected by a temperature sensor 613 configured like a radiation thermometer, for example. The temperature controller 612 controls the discharge flow rate and the refrigerant temperature of the pump 610 based on the mirror surface temperature detected by the temperature sensor 613.

  In addition, for example, a throttle part is provided in the middle of a pipeline that supplies the refrigerant to each of the annular cooling passages 604 (1) to 604 (5), and the flow area of the throttle part is variably controlled by the temperature controller 612. It is good also as a structure. For example, if the flow passage area of the throttle provided in the annular cooling passage 604 (1) at the center of the mirror is increased, the center of the mirror can be cooled more strongly. Configuring this embodiment like this also achieves the same effects as the thirty-fifth embodiment.

  A thirty-seventh embodiment will be described with reference to FIG. In the present embodiment, in the thirty-sixth embodiment, a pump 610 and a cooler 611 are provided in each of the annular cooling passages 604 (1) to 604 (5). In FIG. 62, for convenience, only some pumps and coolers are provided with reference numerals.

  The temperature controller 612B individually controls the flow rate and temperature of the refrigerant flowing through each annular cooling passage 604 (1) to 604 (5) based on a signal from the temperature sensor 613. Configuring this embodiment like this also achieves the same effects as the thirty-fifth embodiment. Furthermore, in this embodiment, since the flow rate and temperature of the refrigerant supplied to the plurality of annular cooling passages 604 (1) to 604 (5) arranged concentrically can be individually controlled, the mirror surface The temperature of 602 can be cooled more appropriately.

  A thirty-eighth embodiment will be described with reference to FIG. FIG. 63 is a cross-sectional view of a mirror 600C with a cooling function according to the present embodiment. In the mirror main body 601, for example, a plurality of cooling elements 620 are disposed. Further, a temperature sensor 621 for detecting the temperature of the mirror surface 602 is provided in the mirror body 601. The cooling element 620 is configured as an element that utilizes the Peltier effect, for example. Of the both ends of the cooling element 620, heat is absorbed at the end on the mirror surface 602 side, and heat is released at the end on the mirror back surface 603 side.

  The temperature controller 612C individually controls the operation of each cooling element 620 based on the detection signal from each temperature sensor 621. Configuring this embodiment like this also achieves the same effects as the thirty-seventh embodiment.

  1: EUV light source device, 2: Laser light source device, 5: EUV exposure device, 10, 10A, 10B: chamber, 11: chamber body, 11 (1): light collecting region, 11 (2): light emitting region, 12: Connection part, 13: Window, 14: EUV collector mirror, 14A: Hole part, 15: Target material supply part, 16: Off-axis parabolic concave mirror, 17: Reflective mirror, 18: Off-axis parabolic convex mirror, 19 : Damper, 20: laser oscillator, 30: amplification system, 31: relay optical system, 32: preamplifier, 33: saturable absorber, 34, 34A to 34E: wavefront corrector, 35: main amplifier, 36, 36A to 36C : Sensor, 36F: Prediction unit, 37: Spatial filter, 38: Reflection mirror, 40: Condensing system, 41: Reflection mirror, 44: Wavefront corrector, 45, 45A: Sensor, 46, 46A: Isolator, 50, 50A, 50B: wavefront correction controller, 60: laser controller, 70: EUV light source controller, 90: prepulse laser oscillator, 95, 95 (1) to 95 (3): wavefront correction unit for prepulse laser light, 96 96 (1) -96 (3): Prepulse laser light sensor, 97, 97 (1) -97 (3): Prepulse laser light wavefront correction controller, 98 (1), 98 (2): Prepulse laser light Amplifier, 99: prepulse laser controller, 100, 100A: angle corrector, 200, 200A to 200J: wavefront curvature corrector, 360, 360A to 360E: optical sensor unit, 600, 600A, 600B, 600C: with cooling function mirror.

The present invention relates to a laser light source device for an extreme ultraviolet light source device and a laser light source device .

The present invention has been made in view of the above problems, and an object thereof is an extreme ultraviolet light source device capable of correcting the direction of a laser beam and the shape of a wavefront into a predetermined direction and a predetermined wavefront shape. It is providing the laser light source device for laser , and a laser light source device . Another object of the present invention is to control the direction of the laser light and the shape of the wavefront at a plurality of positions set on the optical path, and to prevent the correction at each position from competing with each other. Another object is to provide a laser light source device for an extreme ultraviolet light source device and a laser light source device . Further objects of the present invention will become clear from the description of the embodiments described later.

In order to solve the above problems, a laser light source device for an extreme ultraviolet light source device according to the present invention is a laser light source device for use in an extreme ultraviolet light source device, a laser oscillator for outputting a laser beam, said laser the laser beam output from the oscillator, and amplification system for amplifying the at least one amplifier, the laser light is amplified by the amplification system, in order to enter the said chamber in the extreme ultraviolet light source device comprising a light collection system, and at least the amplifier system, at least one first correction for correcting the shape of the counter及beauty wavefront towards the laser beam in the shape of a predetermined direction and a predetermined wavefront and parts, said at least one correction control unit for control the correcting operation by the first correction unit is provided.

Further, engagement Relais chromatography The light source device of the present invention, the amplification system for a laser oscillator for outputting a laser beam, the laser beam output from the laser oscillator, which is amplified by at least one amplifier When, the laser light is amplified by the amplification system, and a light collection system for entering the chamber pole end ultraviolet light source device, at least in the amplification system, the laser light within said amplification system and at least one first correction unit for correcting the shape of the direction and wavefront shape of a predetermined direction and a predetermined wavefront, said first correcting unit by the correction operation the Gosuru for at least one of the braking a correction control unit that provided.

In order to solve the above problems, a laser light source device for an extreme ultraviolet light source device according to the present invention is a laser light source device used in an extreme ultraviolet light source device, and a laser oscillator for outputting laser light, and the laser An amplification system for amplifying the laser light output from an oscillator by at least one amplifier, and for causing the laser light amplified by the amplification system to enter the chamber of the extreme ultraviolet light source device A light collection system, and at least the amplification system includes at least one first correction unit for correcting the direction of the laser light and the shape of the wavefront to a predetermined direction and a predetermined wavefront shape, At least one correction control unit for controlling the correction operation by the first correction unit is provided. The condensing system includes an isolator including a first mirror that absorbs a first polarization component included in the laser light and reflects a second polarization component different from the first polarization component. .

The laser light source device according to the present invention includes a laser oscillator for outputting laser light, an amplification system for amplifying the laser light output from the laser oscillator by at least one amplifier, A condensing system for causing the laser light amplified by the amplification system to enter the chamber of the extreme ultraviolet light source device, and at least the amplification system includes a direction and a wavefront of the laser light in the amplification system. At least one first correction unit for correcting the shape into a predetermined direction and a predetermined wavefront shape, and at least one correction control unit for controlling a correction operation by the first correction unit. Is provided. The condensing system includes an isolator including a first mirror that absorbs a first polarization component included in the laser light and reflects a second polarization component different from the first polarization component. .

Claims (22)

An extreme ultraviolet light source device that generates extreme ultraviolet light by irradiating a target material with laser light to generate plasma,
A target material supply unit for supplying the target material into the chamber;
A laser oscillator for outputting laser light;
An amplification system for amplifying the laser light output from the laser oscillator by at least one amplifier;
A condensing system for irradiating the target material in the chamber with the laser light amplified by the amplification system;
With
At least the amplification system is
It is provided on the optical path of the laser beam and detects the direction and wavefront shape of the laser beam in the amplification system, or detects the beam parameter corresponding to the direction and wavefront shape of the laser beam in the amplification system. A plurality of first detectors for performing,
A plurality of lasers provided on the optical path of the laser beam, for correcting the direction of the laser beam and the shape of the wavefront detected by the plurality of first detectors to a predetermined direction and a predetermined wavefront shape, respectively. A first correction unit;
A plurality of correction control units for controlling correction operations by the plurality of first correction units, respectively, according to detection results by the plurality of first detection units;
A laser controller that corrects the direction of the laser beam and the shape of the wavefront incident on the condensing system by comprehensively controlling the plurality of correction control units;
An extreme ultraviolet light source device. The laser controller is incident on the condensing system by controlling the plurality of correction control units so that the correction operations by the plurality of first correction units are executed according to a predetermined order set in advance. Correcting the direction of the laser beam and the shape of the wavefront;
The extreme ultraviolet light source device according to claim 1. The laser controller controls the plurality of correction control units so as to execute a correction operation in order from the first correction unit located on the upstream side in the traveling direction of the laser light.
The extreme ultraviolet light source device according to claim 2. The amplifier is roughly divided into a preamplifier provided upstream in the traveling direction of the laser light and a main amplifier provided downstream in the traveling direction of the laser light, and the plurality of first correction units are Provided at least one of the upstream side and the downstream side of the preamplifier and at least one of the upstream side and the downstream side of the main amplifier, respectively.
The extreme ultraviolet light source device according to claim 1. After the direction of the laser beam and the shape of the wavefront are corrected to the predetermined direction and the shape of the predetermined wavefront by the plurality of first correction units, the target material supply unit is placed in the chamber. Supply target material,
The extreme ultraviolet light source device according to claim 1. The amplification system is provided with a saturable absorber for absorbing laser light of a predetermined value or less,
The extreme ultraviolet light source device according to claim 1. At least one of the plurality of first correction units adjusts an angle correction function for adjusting an emission angle of the laser light in the predetermined direction, and adjusts the curvature of the wavefront of the laser light to the shape of the predetermined wavefront. And a curvature correction function for
The extreme ultraviolet light source device according to claim 1. At least one of the plurality of first correction units is configured as a reflective optical system including a mirror capable of variably controlling the curvature.
The extreme ultraviolet light source device according to claim 7. At least one of the plurality of first detection units includes a reflection mirror that reflects the laser light, and an optical sensor that detects a state of leakage light that passes through the reflection mirror as an electrical signal.
The extreme ultraviolet light source device according to claim 1. The extreme ultraviolet light source device according to claim 1, comprising a Shack-Hartmann wavefront meter as a detector for detecting the direction of the laser light and the shape of the wavefront. The extreme ultraviolet light source apparatus according to claim 1, further comprising: a beam pointing measuring instrument and a beam profile measuring instrument as detectors for detecting the beam parameters corresponding to the direction of the laser beam and the shape of the wavefront. The extreme ultraviolet light source device according to claim 1, further comprising at least two beam profile measuring devices as detectors for detecting the beam parameters corresponding to the direction of the laser light and the shape of the wavefront. As a detector for detecting a beam parameter corresponding to the direction of the laser beam and the shape of the wavefront, a detector for measuring the temperature distribution of the optical element subjected to a thermal load or energy detection for detecting the energy of the laser The extreme ultraviolet light source device according to claim 1, further comprising: a device for predicting a direction and a wavefront shape of the laser based on a signal from the measuring device or a signal from the energy detector. A prepulse laser oscillator for outputting a prepulse laser beam irradiated to the target material;
A prepulse optical system for irradiating the target material with the prepulse laser light;
At least one second detection unit for detecting a direction and a wavefront shape of the prepulse laser beam, or for detecting a beam parameter corresponding to the direction and the wavefront shape of the prepulse laser beam;
At least one second correction unit for correcting the direction and the wavefront shape of the pre-pulse laser beam detected by the second detection unit into a predetermined direction and a predetermined wavefront shape;
At least one pre-pulse laser beam correction control unit for controlling the correction operation by the second correction unit according to the detection result by the second detection unit;
The extreme ultraviolet light source device according to claim 1. A diamond window is used as a window incident on the chamber or an amplifier window.
The extreme ultraviolet light source device according to claim 1. A mirror for causing the laser beam to be incident on at least one of the plurality of first correction units is provided with a cooling mechanism for axisymmetrically cooling the surface of the mirror with respect to an axis passing through the center of the surface.
The extreme ultraviolet light source device according to claim 1. A laser light source device used for an extreme ultraviolet light source device,
A laser oscillator for outputting laser light;
An amplification system for amplifying the laser light output from the laser oscillator by at least one amplifier;
A condensing system for causing the laser light amplified by the amplification system to enter the chamber of the extreme ultraviolet light source device;
With
At least the amplification system is
A plurality of first correction units provided on the optical path of the laser light, for correcting the direction of the laser light and the shape of the wavefront in the amplification system to a predetermined direction and a predetermined wavefront;
A plurality of correction control units for respectively controlling correction operations by the plurality of first correction units;
A laser controller that corrects the direction of the laser beam and the shape of the wavefront incident on the condensing system by comprehensively controlling the plurality of correction control units;
A laser light source device for an extreme ultraviolet light source device. A diamond window is used as a window incident on the chamber or an amplifier window.
The laser light source device according to claim 17. The plurality of first correction units are provided in the amplification system,
The laser controller controls the plurality of correction control units so as to execute correction operations in order from the first correction unit located on the upstream side in the traveling direction of the laser light among the plurality of first correction units. Correcting the direction of the laser light and the shape of the wavefront incident on the light collection system;
The laser light source device according to claim 17. A mirror for causing the laser beam to be incident on at least one of the plurality of first correction units is provided with a cooling mechanism for axisymmetrically cooling the surface of the mirror with respect to an axis passing through the center of the surface.
The laser light source device according to claim 17. A method of adjusting a laser light source device used in an extreme ultraviolet light source device,
The laser light source device includes an amplification system for amplifying laser light output from a laser oscillator by at least one amplifier, and a condensing for allowing the laser light amplified by the amplification system to enter the chamber. System and
Outputting the laser beam from the laser oscillator,
Detecting the direction of the laser beam amplified by the amplifier and the shape of the wavefront at at least two points on the optical path of the laser beam;
The direction of the laser beam and the wavefront of the laser beam at at least two points on the optical path of the laser beam so that the direction and the wavefront shape detected at the two points are respectively a predetermined direction and a predetermined wavefront shape. Correct the shape,
The direction of the laser light and the shape of the wavefront incident on the condensing system are controlled by comprehensively controlling correction of the direction of the laser light and the shape of the wavefront at at least two points on the optical path of the laser light. For adjusting laser light source device for extreme ultraviolet light source device. A method for controlling an extreme ultraviolet light source device that generates extreme ultraviolet light by irradiating a target material with laser light to generate plasma,
The extreme ultraviolet light source device includes an amplification system for amplifying laser light output from a laser oscillator by a plurality of amplifiers,
Detection by detecting at least two points on the optical path of the laser light, the direction of the laser light and the shape of the wavefront in the amplification system, or the beam parameter corresponding to the direction of the laser light and the shape of the wavefront in the amplification system Steps,
According to the detection result of the detection step at the at least two points on the optical path of the laser beam, the direction of the laser beam and the shape of the wavefront at the at least two points detected by the detection step are respectively predetermined. A correction step of correcting the direction of the laser beam and the shape of the wavefront at at least two points on the optical path of the laser beam so as to be in the direction of
An overall control step for comprehensively controlling the correction step at at least two points on the optical path of the laser beam;
The method of controlling the extreme ultraviolet light source device that executes

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