Optical pulse stretcher, laser device, and method for manufacturing electronic device

Abstract

An optical pulse stretcher for stretching the pulse width of pulsed laser light, the optical pulse stretcher comprising: a polarizer that separates a component of incident pulsed laser light that has a specific polarization direction; delay optics including a plurality of mirrors for propagating the pulsed laser light that has been reflected by or transmitted through the polarizer; and a first Faraday rotator that includes a first magnet and a first Faraday material, is disposed on the optical path of the delay optics, and rotates the polarization direction of the pulsed laser light.

Description

[Technical Field]

[0001] The present disclosure relates to optical pulse stretchers, laser apparatus and methods for manufacturing electronic devices. [Background technology]

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

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

[0004] [Patent Document 1] U.S. Patent No. 6,067,311 [Patent Document 2] Summary of JP 2006-186046 A

[0005] An optical pulse stretcher according to one aspect of the present disclosure is an optical pulse stretcher that stretches the pulse width of pulsed laser light, and includes: a polarizer that separates components of a specific polarization direction of incident pulsed laser light; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; and a first Faraday rotator that includes a first magnet and a first Faraday material, is positioned on the optical path of the delay optical system, and rotates the polarization direction of the pulsed laser light.

[0006] A laser device according to another aspect of the present disclosure includes an oscillator that outputs pulsed laser light, and an optical pulse stretcher that stretches the pulse width of the pulsed laser light, wherein the optical pulse stretcher includes a polarizer that separates a specific polarization direction of the incident pulsed laser light, a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates, and a first Faraday rotator that includes a first magnet and a first Faraday material, is positioned on an optical path of the delay optical system, and rotates the polarization direction of the pulsed laser light.

[0007] According to another aspect of the present disclosure, a method for manufacturing an electronic device includes generating laser light whose pulse width has been stretched by a laser apparatus including: an oscillator that outputs pulsed laser light; and an optical pulse stretcher that stretches the pulse width of the pulsed laser light, the optical pulse stretcher including a polarizer that separates a specific polarization direction of the incident pulsed laser light; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; and a first Faraday rotator that includes a first magnet and a first Faraday material and is disposed on an optical path of the delay optical system and rotates the polarization direction of the pulsed laser light, the method including: outputting the laser light to an exposure apparatus; and exposing a photosensitive substrate in the exposure apparatus to the laser light to manufacture an electronic device. [Brief explanation of the drawings]

[0008] Some embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1]FIG. 1 is a graph showing an example of the relationship between the angle between the transmission axis of a polarizer and the polarization direction of incident light, and the transmittance. [Figure 2] FIG. 2 shows a schematic configuration of a laser device according to a comparative example. [Figure 3] FIG. 3 shows a schematic configuration of the laser device according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the details of the configuration of the Faraday rotator. [Figure 5] FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. [Figure 6] FIG. 6 is an explanatory diagram showing an example of the polarization direction of a pulsed laser beam incident on an optical pulse stretcher (OPS) and the polarization direction of a pulsed laser beam that has passed through the OPS. [Figure 7] FIG. 7 is a flowchart illustrating a first example of a control process in the laser device according to the first embodiment. [Figure 8] FIG. 8 is a flowchart illustrating a second example of the control process in the laser device according to the first embodiment. [Figure 9] FIG. 9 is a flowchart showing an example of a subroutine that is applied to step S14 in FIG. 7 or step S24 in FIG. [Figure 10] FIG. 10 is a flowchart showing a modified example of the TIS control in the laser apparatus according to the first embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of a subroutine of the process applied to step S40 in FIG. [Figure 12] FIG. 12 is a flowchart showing an example of a subroutine of the process applied to step S46 in FIG. [Figure 13] FIG. 13 shows a schematic configuration of a laser device according to a first modification of the first embodiment. [Figure 14] FIG. 14 schematically illustrates the configuration of a laser device according to Modification 2 of Embodiment 1. In FIG. [Figure 15] FIG. 15 shows a schematic configuration of a laser device according to the second embodiment. [Figure 16]FIG. 16 is an explanatory diagram showing an example of the polarization direction of the pulsed laser light incident on the second Faraday rotator and the polarization direction of the pulsed laser light that has passed through the OPS. [Figure 17] FIG. 17 is a flowchart illustrating an example of a control process in the laser device according to the second embodiment. [Figure 18] FIG. 18 is a flowchart showing an example of a subroutine of the process applied to step S74 in FIG. [Figure 19] FIG. 19 schematically illustrates the configuration of a laser device according to a first modification of the second embodiment. [Figure 20] FIG. 20 schematically illustrates the configuration of a laser device according to Modification 2 of Embodiment 2. In FIG. [Figure 21] FIG. 21 shows a schematic configuration example of an exposure apparatus. Embodiment

[0009] -table of contents- 1. Explanation of terms 1.1 Polarizer 1.2 TIS (Time-Integral Square) 2. Overview of the laser device according to the comparative example 2.1 Configuration 2.2 Operation 2.3 Challenges 3. Embodiment 1 3.1 Configuration 3.2 Operation 3.3 Control Flow Example 1 3.4 Control Flow Example 2 3.5 Effects 3.6 Variation 1 3.6.1 Configuration 3.6.2 Operation 3.6.3 Effects 3.7 Variation 2 3.7.1 Configuration 3.7.2 Operation 3.7.3 Effects 4. Embodiment 2 4.1 Configuration 4.2 Operation 4.3 Control Flow Examples 4.4 Effects 4.5 Variation 1 4.5.1 Configuration 4.5.2 Operation 4.5.3 Effects 4.6 Variation 2 4.6.1 Configuration 4.6.2 Operation 4.6.3 Effects 5. Modifications of the laser device 6. Manufacturing methods for electronic devices 7.Other Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show some examples of the present disclosure and do not limit the content of the present disclosure. Furthermore, not all of the configurations and operations described in each embodiment are necessarily essential as the configurations and operations of the present disclosure. Note that the same components are given the same reference symbols, and redundant explanations will be omitted.

[0010] 1. Explanation of terms 1.1 Polarizer A polarizer is an optical element that separates light with a specific polarization direction (transmission axis direction) from light with a polarization direction perpendicular to it. When the polarization direction of light is tilted by θ degrees with respect to the transmission axis of the polarizer, each polarization component is separated at the ratio shown below. The relationship shown below is called Malus' law.

[0011]

number

[0012] Fig. 1 is a graph showing an example of the relationship between the angle between the transmission axis of a polarizer and the polarization direction of incident light and the transmittance, where the horizontal axis represents the angle θ between the transmission axis of the polarizer and the polarized light, and the vertical axis represents the transmittance.

[0013] 1.2 TIS (Time-Integral Square) TIS is an index that represents the pulse width of the laser light and is calculated using the following formula:

[0014]

number

[0015] Here, I(t) represents the light intensity over time.

[0016] 2. Overview of the laser device according to the comparative example 2.1 Configuration 2 is a schematic diagram illustrating the configuration of a laser device 2 according to a comparative example. The comparative example of the present disclosure refers to a configuration that the applicant recognizes as being known only by the applicant, and is not a publicly known example that the applicant acknowledges. The laser device 2 includes an oscillator 10, an optical pulse stretcher (OPS) 50, a monitor module 60, and a laser control unit 70.

[0017] An OPS 50 and a monitor module 60 are arranged in this order on the optical path of the pulsed laser light output from the oscillator 10. The oscillator 10 includes a chamber 14, a rear mirror 17, and an output coupling mirror 18. The output coupling mirror 18 and the rear mirror 17 are arranged to form an optical resonator.

[0018] Chamber 14 is disposed on the optical path of the optical resonator and includes a pair of discharge electrodes 15a, 15b and two windows 16a, 16b through which the laser light passes. An excimer laser gas is introduced into chamber 14. The excimer laser gas may include, for example, Ar gas or Kr gas as a rare gas, F gas as a halogen gas, and Ne gas as a buffer gas.

[0019] The OPS 50 includes a beam splitter 52 and concave mirrors 54a, 54b, 54c, and 54d, which form a delay optical path. The beam splitter 52 is disposed on the optical path of the laser light and is coated with a film that transmits a portion of the incident pulsed laser light and reflects the other portion of the pulsed laser light. The reflectance of the beam splitter 52 is preferably approximately 60%. The beam splitter 52 outputs the pulsed laser light that has passed through the beam splitter 52 from the laser device 2 as described above.

[0020] The concave mirrors 54a to 54d all have approximately the same focal length f. The concave mirrors 54a to 54d are arranged to satisfy the following relationship: The concave mirrors 54a to 54d are arranged so that the image of the laser light reflected by the beam splitter 52 at the position of the beam splitter 52 is inverted and formed by the concave mirrors 54a and 54b, and then returned to the beam splitter 52 by the concave mirrors 54c and 54d, where it is again inverted and formed as an image. In this case, the delay optical path length L is 8f.

[0021] The monitor module 60 includes a beam splitter 62 and an optical sensor 63. The optical sensor 63 may be, for example, a biplanar discharge tube or a photodiode. Data measured using the optical sensor 63 is sent to the laser control unit 70.

[0022] 2.2 Operation Under the control of the laser control unit 70, a high-voltage pulse is applied between the discharge electrodes 15a and 15b in the chamber 14 from a power supply (not shown). When a discharge occurs between the discharge electrodes 15a and 15b in the chamber 14, the laser gas is excited, and an optical resonator formed by the output coupling mirror 18 and the rear mirror 17 outputs pulsed laser light with an ultraviolet wavelength of 150 nm to 380 nm from the output coupling mirror 18.

[0023] The pulsed laser light output from the output coupling mirror 18 enters the OPS 50, and a portion of the pulsed laser light passes through the delay optical path in the OPS 50 multiple times, thereby being expanded to a predetermined pulse width.

[0024] A portion of the pulsed laser light that has passed through the OPS 50 passes through the beam splitter 62 and is output from the laser device 2. Another portion of the pulsed laser light that has passed through the OPS 50 is reflected by the beam splitter 62 and enters the optical sensor 63. The pulse energy E is measured by the optical sensor 63, and the obtained data is sent from the monitor module 60 to the laser control unit 70.

[0025] The laser control unit 70 controls the voltage of the high voltage pulse output from a power supply (not shown) so that the difference ΔE between the target pulse energy Et and the measured pulse energy E approaches zero.

[0026] 2.3 Challenges There are two methods for changing the pulse width or pulse waveform expanded by the OPS 50, for example:

[0027] [Method 1] Changing the circular optical path length [Method 2] Changing the reflectivity of beam splitter 52 Method 1 requires the preparation in advance of multiple types of standard OPS housings with different circular optical path lengths. Method 2 requires the preparation in advance of multiple types of standard beam splitter 52 with different reflectances. Furthermore, both Method 1 and Method 2 require replacement with standard beam splitters, which is a significant effort. Furthermore, only the configuration of the prepared standard beam splitter can be changed, and the degree of freedom in making changes is limited, making it difficult to optimize the pulse width or pulse waveform.

[0028] 3. Embodiment 1 3.1 Configuration 3 is a schematic diagram showing the configuration of a laser device 2A according to embodiment 1. Differences between the configuration of the laser device 2A shown in FIG. 3 and that shown in FIG. 2 will be described.

[0029] The window 16b of the chamber 14 may be disposed at, for example, the Brewster angle. The pulsed laser light emitted from the chamber 14 may be linearly polarized or randomly polarized.

[0030] The laser device 2A includes an OPS 51 instead of the OPS 50 of FIG. 2. In the OPS 51, a Faraday rotator 91 is disposed on a delay optical path formed by the concave mirrors 54a to 54d. The Faraday rotator 91 is disposed, for example, on the optical path between the concave mirrors 54b and 54c. The Faraday rotator 91 may be disposed anywhere on the delay optical path. The Faraday rotator 91 is preferably disposed on the optical path of the collimated light.

[0031] 2, a polarizer 53 is disposed within the OPS 51. The polarizer 53 is coated with a film that highly transmits P-polarized light and highly reflects S-polarized light.

[0032] The Faraday rotator 91 includes a Faraday material 95 and a magnet 96. The Faraday material 95 may be calcium fluoride (CaF2) crystal or synthetic quartz. The magnet 96 may be a permanent magnet or an electromagnet.

[0033] Fig. 4 is a cross-sectional view showing the details of the configuration of the Faraday rotator 91. Fig. 4 shows a cross section parallel to the optical axis of the pulsed laser beam. The center line CL in Fig. 4 represents the center of the magnet 96. Fig. 5 is a cross-sectional view taken along line 5-5 in Fig. 4.

[0034] An actuator 120 that controls the amount of rotation of the polarization direction is disposed on the Faraday rotator 91. The actuator 120 may be, for example, a mechanism that moves the Faraday material 95 relative to the magnet 96 in the optical axis direction of the pulsed laser light. The amount (maximum amount) that the actuator 120 can move the Faraday material 95 is preferably equal to or greater than half the length of the Faraday material 95 in the optical axis direction of the pulsed laser light. The minimum unit of movement of the Faraday material 95 by the actuator 120 may be, for example, approximately 0.2 mm. The actuator 120 may also be configured to move the magnet 96 relative to the Faraday material 95 in the optical axis direction of the pulsed laser light.

[0035] The Faraday rotator 91 is an example of a "first Faraday rotator" in the present disclosure. The Faraday material 95 and the magnet 96 are an example of a "first Faraday material" and a "first magnet" in the present disclosure. The actuator 120 is an example of a "first actuator" in the present disclosure.

[0036] The actuator 120 is not limited to a moving mechanism that moves the Faraday material 95 and the magnet 96 relative to each other, but may be, for example, a mechanism that controls the current flowing through the electromagnet using the magnet 96 as an electromagnet, or a mechanism that controls the temperature of the magnet 96 using a heater or the like. In this specification, the term "actuator" is not limited to a device that performs a mechanical operation, but is used as a conceptual term that also includes a mechanism that can change the amount of rotation of the polarization direction by the Faraday rotator 91 by changing the current, temperature, etc.

[0037] Since the cross section perpendicular to the optical axis of the pulsed laser beam is a vertically long rectangle, the cross section of the Faraday material 95 may also be a vertically long rectangle. The cross section of the magnetic field generating unit 97 of the magnet 96 on which the Faraday material 95 is disposed may also be a vertically long rectangle oriented in the same direction as the cross section of the Faraday material 95.

[0038] The Faraday material 95 is placed in a magnetic field generating unit 97 of a magnet 96 while being held by a Faraday material holder 100. The cross section of the Faraday material holder 100 perpendicular to the optical axis of the pulsed laser light may be a vertically long rectangle, similar to the Faraday material 95. A through-hole 101 is formed at one end of the vertically long rectangle in the longitudinal direction of the Faraday material holder 100, and a female screw hole 102 is formed at the other end.

[0039] A guide shaft 124 is inserted into the through hole 101, and a rod-shaped male screw 126 is screwed into the female screw hole 102. The Faraday material holder 100 is held by plates 121a and 121b via the guide shaft 124 and the male screw 126. The male screw 126 is rotatably held and connected to an actuator 120. The plates 121a and 121b also hold a magnet 96. The actuator 120 is an example of a "first moving mechanism" in this disclosure.

[0040] 3, the laser device 2A also includes an OPS control unit 72 that receives the measurement results of the optical sensor 63 and controls the actuator 120. The OPS control unit 72 is connected to the laser control unit 70. The OPS control unit 72 can receive the measurement results of the optical sensor 63 via the laser control unit 70.

[0041] Each of the laser control unit 70 and the OPS control unit 72 is configured using a processor. The processor of the present disclosure is a processing device including a storage device in which a control program is stored and a CPU (Central Processing Unit) that executes the control program. The processor is specially configured or programmed to execute the various processes included in the present disclosure. The processor may include an integrated circuit such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). The processing function of the OPS control unit 72 may be incorporated into the laser control unit 70. The functions of the laser control unit 70 and the OPS control unit 72 may be realized by one or more processors.

[0042] 3.2 Operation When pulsed laser light polarized in a specific direction passes through a Faraday material 95 to which a magnetic field is applied, the polarization direction rotates. The amount of rotation of the polarization direction of the pulsed laser light in the Faraday rotator 91 is determined by the strength of the magnetic field, physical quantities such as the refractive index of the Faraday material 95, and the length of the Faraday material 95.

[0043] The strength of the magnetic field of the magnetic field generating unit 97 of the magnet 96 changes depending on the position in the optical axis direction. Therefore, by changing the position of the Faraday material 95 relative to the magnet 96 in the optical axis direction of the pulsed laser light using the actuator 120, the amount of rotation of the polarization of the pulsed laser light in the Faraday rotator 91 can be controlled.

[0044] The pulsed laser light output from the oscillator 10 is polarized in a specific direction, and the component parallel to the transmission axis of the polarizer 53 is transmitted through the polarizer 53 and passes through the OPS 51. The component perpendicular to the transmission axis of the polarizer 53 is reflected by the polarizer 53 and propagates along the delay optical path within the OPS 51.

[0045] Fig. 6 is an explanatory diagram showing an example of the polarization direction of the pulsed laser light incident on the OPS 51 and the polarization direction of the pulsed laser light that has passed through the OPS 51. The double-headed arrow shown in the circle in Fig. 6 indicates the polarization direction of the pulsed laser light. Fig. 6 shows the polarization direction of the pulsed laser light when viewed in the propagation direction of the pulsed laser light.

[0046] 6, when the polarization direction of the pulsed laser light output from the oscillator 10 is perpendicular to the transmission axis of the polarizer 53, all components of the pulsed laser light are reflected and propagate through the delay optical path within the OPS 51. When the polarization direction of the pulsed laser light output from the oscillator 10 is parallel to the transmission axis of the polarizer 53, all components of the pulsed laser light are transmitted and do not propagate through the delay optical path within the OPS 51, so that the pulse width cannot be extended and the pulse waveform cannot be changed.

[0047] In Figure 6, the components of the pulsed laser light that pass through polarizer 53 pass through OPS 51, and the components of the pulsed laser light that are reflected by polarizer 53 propagate through a delay optical path within OPS 51, but the components of the pulsed laser light that pass through polarizer 53 may propagate through a delay optical path within OPS 51, and the components of the pulsed laser light that are reflected by polarizer 53 may pass through OPS 51.

[0048] The pulsed laser light reflected by polarizer 53, concave mirror 54a, and concave mirror 54b has its polarization direction rotated by Faraday rotator 91. The pulsed laser light with its polarization direction rotated returns to polarizer 53, and the component parallel to the transmission axis of polarizer 53 is transmitted and propagates again along the delay optical path within OPS 2. The component perpendicular to the transmission axis of polarizer 53 is reflected and passes through OPS 51.

[0049] In this specification, the terms "orthogonal" and "perpendicular" are not limited to strictly orthogonal or perpendicular, but also include the concepts of approximately perpendicular or substantially perpendicular, including a range of angular difference that is practically acceptable and does not lose its technical significance, unless otherwise specified, unless it is clear from the context. Similarly, in this specification, the term "parallel" is not limited to strictly parallel, but also includes the concept of approximately parallel, including a range of angular difference that is practically acceptable and does not lose its technical significance, unless otherwise specified, unless it is clear from the context.

[0050] The OPS control unit 72 can change the amount of rotation of the polarization direction by controlling the actuator 120 of the Faraday rotator 91. The OPS control unit 72 may control the actuator 120 to move the Faraday material 95 in the optical axis direction by a predetermined amount to change the polarization direction, and may determine the amount of rotation of the Faraday rotator 91 based on the measurement results of the optical sensor 63 for each position of the Faraday material 95.

[0051] The concave mirrors 54a, 54b, 54c, and 54d that form the delay optical path of the OPS 51 are an example of a "delay optical system" in the present disclosure. The concave mirrors 54a, 54b, 54c, and 54d are an example of a "plurality of mirrors" in the present disclosure.

[0052] 3.3 Control Flow Example 1 Fig. 7 is a flowchart showing Example 1 of the control process in the laser apparatus 2A according to Embodiment 1. Fig. 7 shows a flow in which the OPS control unit 72 acquires a pulse waveform from the optical sensor 63, calculates a pulse width (TIS), and controls the Faraday rotator 91 so that the TIS satisfies a target.

[0053] In step S11, the OPS control unit 72 receives a target TIS. The target TIS may be received from, for example, a processing tool or an exposure tool (not shown).

[0054] Thereafter, in step S12, the OPS control unit 72 issues a request for oscillation of the target TIS setting.

[0055] In step S13, the OPS control unit 72 determines whether or not oscillation of the TIS setting is permitted. If the determination result in step S13 is No, the OPS control unit 72 repeats step S13.

[0056] If the determination result in step S13 is Yes, the OPS control unit 72 proceeds to step S14. In step S14, the OPS control unit 72 performs first TIS control. Note that in the drawings, the first TIS control is referred to as "TIS control 1," for example. The subroutine of the first TIS control applied in step S14 will be described later with reference to FIG. 8.

[0057] In step S15 after step S14, the OPS control unit 72 transmits a signal indicating the completion of setting the target TIS.

[0058] After step S15, the OPS control unit 72 ends the flowchart of FIG.

[0059] Fig. 8 is a flowchart showing Example 2 of the control process in the laser device 2A according to Embodiment 1. The flowchart shown in Fig. 8 may be executed, for example, after the flowchart in Fig. 7 is completed.

[0060] In step S20, the laser control unit 70 starts the operation of the laser device 2A.

[0061] In step S21, the OPS control unit 72 determines whether or not a target TIS has been received. If the determination result in step S21 is Yes, the OPS control unit 72 proceeds to step S22. Each step from step S22 to step S25 may be the same as the corresponding step from step S12 to step S15 in FIG. 7, and redundant explanations will be omitted.

[0062] In step S26 after step S25, the laser control unit 70 determines whether or not to terminate the operation of the laser device 2A. If the determination result in step S26 is No, the process returns to step S21.

[0063] If the determination result in step S21 is No, the OPS control unit 72 proceeds to step S26.

[0064] If the determination result in step S26 is Yes, the laser control unit 70 stops the laser device 2A, and the flowchart in FIG. 8 ends.

[0065] FIG. 9 is a flowchart showing an example of a subroutine that is applied to step S14 in FIG. 7 or step S24 in FIG.

[0066] 9 starts, in step S30, the OPS control unit 72 moves the position of the Faraday material 95 in the optical axis direction relative to the magnet 96 to an initial position. The position of the Faraday material 95 in the optical axis direction is defined, for example, by the center position of the Faraday material 95. The initial position of the Faraday material 95 may be, for example, the center position of the magnet 96.

[0067] Next, in step S32, the OPS control unit 72 causes the oscillator 10 to output a pulsed laser beam.

[0068] In step S33, the OPS control unit 72 causes the optical sensor 63 to measure the pulse waveform.

[0069] Then, in step S34, the OPS control unit 72 calculates the TIS from the measured pulse waveform, and stores the calculated TIS value in association with the position of the Faraday material 95.

[0070] Thereafter, in step S36, the OPS control unit 72 determines whether the position of the Faraday material 95 is at the movement end position. If the determination result in step S36 is No, the OPS control unit 72 proceeds to step S37 and moves the Faraday material 95 in the optical axis direction. The amount of movement at this time may be a predetermined amount, such as 0.5 mm. After step S37, the process returns to step S33.

[0071] If the determination result in step S36 is Yes, the OPS control unit 72 proceeds to step S38.

[0072] In step S38, the OPS control unit 72 stops the output of the pulsed laser light.

[0073] Thereafter, in step S39, the OPS control unit 72 moves the Faraday material 95 to a position that satisfies the target value of TIS (target TIS). Note that instead of step S39, the OPS control unit 72 may move the Faraday material 95 to a position where the TIS is the longest. The OPS control unit 72 controls the actuator 120 so that the TIS is equal to or greater than the target value.

[0074] After step S39, the OPS control unit 72 ends the flowchart of FIG. 9 and returns to the flowchart of FIG.

[0075] 3.4 Control Flow Example 2 Fig. 10 is a flowchart showing a modified example of TIS control in the laser apparatus 2A according to embodiment 1. The flowchart in Fig. 10 shows an example of a method for creating table data describing the relationship between the TIS and the position of the Faraday material 95 in advance, and controlling the Faraday rotator 91 based on this table data.

[0076] In step S40, the OPS control unit 72 creates and stores table data. The subroutine for the process applied in step S40 will be described later with reference to FIG.

[0077] After step S40, in step S41, the OPS control unit 72 transmits a signal indicating that preparation for oscillation is complete.

[0078] In step S42, the laser control unit 70 starts the operation of the laser device 2A. Each of steps S43 to S48 may be the same as the corresponding steps S21 to S26 in Fig. 8. However, step S46 is included in Fig. 10 instead of step S24 in Fig. 8.

[0079] In step S46, the OPS control unit 72 performs second TIS control. The subroutine for the second TIS control applied in step S46 will be described later with reference to FIG.

[0080] FIG. 11 is a flowchart showing an example of a subroutine of the process applied to step S40 in FIG.

[0081] 11 starts, in step S50, the OPS control unit 72 moves the position of the Faraday material 95 in the optical axis direction relative to the magnet 96 to an initial position. Each of steps S50 to S54 may be the same as the corresponding steps S30 to S34 in FIG.

[0082] In step S55 after step S54, the OPS control unit 72 records the position of the Faraday material 95 and the TIS data in the table data.

[0083] Thereafter, in step S56, the OPS control unit 72 determines whether the position of the Faraday material 95 is the movement final position. Each of steps S56 to S58 may be the same as the corresponding step of step S36 to step S38 in FIG.

[0084] By repeating the loop from step S53 to step S57, table data indicating the relationship between the position of the Faraday material 95 and the TIS is acquired. Note that since the position of the Faraday material 95 corresponds to the control amount of the actuator 120, the table data may specify the relationship between the TIS and the control amount of the actuator 120.

[0085] After step S58, the OPS control unit 72 ends the flowchart of FIG. 11 and returns to the flowchart of FIG.

[0086] Fig. 12 is a flowchart showing an example of a subroutine of the process applied to step S46 in Fig. 10. When the flowchart in Fig. 12 starts, in step S60, the OPS control unit 72 reads out the target position of the Faraday material 95 that can achieve the target TIS from the table data.

[0087] Then, in step S61, the OPS control unit 72 drives the actuator 120 to move the Faraday material 95 to the target position.

[0088] After step S61, the OPS control unit 72 ends the flowchart of FIG. 12 and returns to the flowchart of FIG.

[0089] 3.5 Effects According to the OPS 51 of the first embodiment, the pulse width (TIS) can be changed to any desired value without changing the optical system components such as the circuit path length or optical parts. Furthermore, according to the OPS 51 of the first embodiment, the target value of the pulse width (TIS) can be met without changing the optical system components.

[0090] 3.6 Variation 1 3.6.1 Configuration 13 is a schematic diagram showing the configuration of a laser device 2B according to Modification 1 of Embodiment 1. Differences between the configuration shown in FIG. 13 and that shown in FIG.

[0091] The oscillator 10A of the laser device 2B includes a line narrowing module (LNM) 11 instead of the rear mirror 17 in FIG. 3. The LNM 11 includes a prism beam expander 12 and a grating 13 for narrowing the spectral linewidth. The prism beam expander 12 and the grating 13 are arranged in a Littrow configuration in which the angle of incidence and the angle of diffraction match. The LNM 11 is an example of the "line narrowing optical system" in this disclosure.

[0092] The output coupling mirror 18 is a reflecting mirror with a reflectance of 40% to 60%. The output coupling mirror 18 and the LNM 11 are arranged to form an optical resonator.

[0093] 3.6.2 Operation Under the control of the laser control unit 70, a high-voltage pulse is applied from a power supply (not shown) to the discharge electrodes 15a and 15b in the chamber 14. When a discharge occurs between the discharge electrodes 15a and 15b in the chamber 14, the laser gas is excited, and an optical resonator formed by the output coupling mirror 18 and the LNM 11 outputs a narrowband pulsed laser beam with an ultraviolet wavelength of 150 nm to 380 nm from the output coupling mirror 18. Other operations are the same as those of the laser apparatus 2A according to the first embodiment described with reference to FIG.

[0094] 3.6.3 Effects According to the laser device 2B according to the first modification of the first embodiment, it is possible to extend the pulse width and change the pulse waveform of pulsed laser light having a narrowed ultraviolet wavelength.

[0095] Furthermore, the laser device 2B can change the narrowband ultraviolet wavelength pulse laser light to any pulse width and pulse waveform without changing the components of the optical system.

[0096] 3.7 Variation 2 3.7.1 Configuration 14 is a schematic diagram showing the configuration of a laser device 2C according to Modification 2 of Embodiment 1. Differences between the configuration shown in FIG. 14 and that shown in FIG.

[0097] 3 is configured as a MOPO (Master Oscillator Power Oscillator) type system including an oscillation-stage laser 10A and an amplification-stage laser 30. An MO beam steering unit 20 is disposed between the oscillation-stage laser 10A and the amplification-stage laser 30, and a PO beam steering unit 40 is disposed between the amplification-stage laser 30 and the OPS 51.

[0098] The oscillation-stage laser 10A includes an LNM 11, a chamber 14, and an output coupling mirror 18. The configuration of the oscillation-stage laser 10A may be similar to that of the oscillator 10 described with reference to FIG.

[0099] The MO beam steering unit 20 includes a high-reflection mirror 21 and a high-reflection mirror 22, and is arranged so that the pulsed laser light output from the oscillation-stage laser 10A is incident on the amplification-stage laser 30.

[0100] The amplification-stage laser 30 includes a chamber 34, a rear mirror 37, and an output coupling mirror 38. The output coupling mirror 38 and the rear mirror 37 form an optical resonator, and the chamber 34 is disposed on the optical path of this optical resonator. The amplification-stage laser 30 is an example of an "amplifier" in this disclosure.

[0101] The configuration of the chamber 34 may be similar to that of the chamber 14. The chamber 34 includes a pair of discharge electrodes 35a, 35b and two windows 36a, 36b, and an excimer laser gas is introduced into the chamber 34.

[0102] The rear mirror 37 may be a partial reflection mirror with a reflectance of 50% to 90%, and the output coupling mirror 38 may be a partial reflection mirror with a reflectance of 10% to 30%.

[0103] The PO beam steering unit 40 includes a high-reflection mirror 43 and a high-reflection mirror 44 , and is arranged so that the pulsed laser light output from the amplification-stage laser 30 enters the OPS 51 .

[0104] 3.7.2 Operation Under the control of the laser control unit 70, a high-voltage pulse is applied between the discharge electrodes 15a and 15b in the chamber 14 from a power supply (not shown). When a discharge occurs between the discharge electrodes 15a and 15b in the chamber 14, the laser gas is excited, and an optical resonator formed by the output coupling mirror 18 and the LNM 11 outputs a narrowband pulsed laser beam with an ultraviolet wavelength of 150 nm to 380 nm from the output coupling mirror 18.

[0105] The pulsed laser light output from the output coupling mirror 18 passes through the MO beam steering unit 20 and enters the rear mirror 37 of the amplification stage laser 30 as seed light. The pulsed laser light output from the output coupling mirror 18 is an example of the "first pulsed laser light" in this disclosure.

[0106] At the timing when the seed light that has passed through the rear mirror 37 enters the chamber 34, a high-voltage pulse is applied between the discharge electrodes 35a and 35b in the chamber 34 from a power supply (not shown). When a discharge occurs between the discharge electrodes 35a and 35b in the chamber 34, the laser gas is excited, and the seed light is amplified by a Fabry-Perot optical resonator composed of the output coupling mirror 38 and the rear mirror 37, and the amplified pulsed laser light is output from the output coupling mirror 38.

[0107] The pulsed laser light output from the amplification stage laser 30 is incident on the OPS 51 via the PO beam steering unit 40. The operation of the OPS 51 is the same as in the first embodiment.

[0108] 3.7.3 Effects According to the laser device 2C according to the second modification of the first embodiment, it is possible to extend the pulse width and change the pulse waveform of high-energy pulsed laser light with a narrowed ultraviolet wavelength.

[0109] Furthermore, the laser device 2C can change the high-energy pulsed laser light of narrowed ultraviolet wavelength to any pulse width and pulse waveform without changing the components of the optical system.

[0110] 4. Embodiment 2 4.1 Configuration Fig. 15 shows a schematic configuration of a laser device 2D according to embodiment 2. Differences between the configuration shown in Fig. 15 and Fig. 3 will be described.

[0111] In the laser apparatus 2D, a Faraday rotator 202 is disposed upstream of the OPS 51. The Faraday rotator 202 includes a Faraday material 205 and a magnet 206. The structure of the Faraday rotator 202 may be similar to the structure of the Faraday rotator 91 described with reference to FIGS.

[0112] The Faraday rotator 202 is provided with an actuator (not shown) that moves the Faraday material 205 relative to the magnet 206 in the optical axis direction of the pulsed laser light. Hereinafter, for convenience of notation, the Faraday rotator 91 disposed in the delay optical path of the OPS 51 will be referred to as the first Faraday rotator 91, and the Faraday rotator 202 disposed upstream of the OPS 51 will be referred to as the second Faraday rotator 202. Furthermore, the Faraday material 95, the magnet 96, and the actuator 120 of the first Faraday rotator 91 will be referred to as the first Faraday material 95, the first magnet 96, and the first actuator 120, and the Faraday material 205, the magnet 206, and the actuator of the second Faraday rotator 202 will be referred to as the second Faraday material 205, the second magnet 206, and the second actuator.

[0113] The maximum movement amount of the second Faraday material 205 by the second actuator is preferably equal to or greater than half the length of the second Faraday material 205 in the optical axis direction of the pulsed laser beam. The minimum movement unit of the second actuator may be, for example, about 0.2 mm. The second actuator may move the second magnet 206 in the optical axis direction of the pulsed laser beam relative to the second Faraday material 205. The second actuator is an example of a "second movement mechanism" in the present disclosure.

[0114] 4.2 Operation FIG. 16 is an explanatory diagram showing an example of the polarization direction of the pulsed laser light incident on the second Faraday rotator 202 and the polarization direction of the pulsed laser light that has passed through the OPS 51. In FIG.

[0115] The pulsed laser light polarized in a specific direction output from the amplification stage laser 30 has its polarization direction rotated by the second Faraday rotator 202. Figure 16 shows an example in which the polarization direction is rotated clockwise.

[0116] The pulsed laser light with its polarization direction rotated is transmitted through the polarizer 53, with the component parallel to the transmission axis of the polarizer 53 being transmitted and passing through the OPS 51. The component perpendicular to the transmission axis of the polarizer 53 is reflected by the polarizer 53 and propagates along the delay optical path within the OPS 51.

[0117] In Figure 16, the components of the pulsed laser light that have passed through polarizer 53 pass through OPS 51, and the components of the pulsed laser light that have been reflected by polarizer 53 propagate through a delay optical path within OPS 51; however, the components of the pulsed laser light that have passed through polarizer 53 may propagate through a delay optical path within OPS 51, and the components of the reflected pulsed laser light may pass through OPS 51.

[0118] The pulsed laser light reflected by the polarizer 53 has its polarization direction rotated by the first Faraday rotator 91 on the delay optical path within the OPS 51. The pulsed laser light, whose polarization direction has been rotated by the first Faraday rotator 91, returns to the polarizer 53, and the component parallel to the transmission axis of the polarizer 53 is transmitted and propagates again along the delay optical path within the OPS 51. Of the pulsed laser light that has propagated along the delay optical path and returned to the polarizer 53, the component perpendicular to the transmission axis of the polarizer 53 is reflected and passes through the OPS 51.

[0119] According to the configuration of Figure 16, the polarization direction of the zeroth circumnavigation light that passes through polarizer 53 and is output from OPS51 without circulating through the delay optical path of OPS51 is different from the polarization direction of the circumnavigation light from the first circumnavigation onwards that is output from OPS51 after circulating through the delay optical path one or more times, and since the amount of polarization rotation can be adjusted in two places, there is even greater freedom in changing the pulse width, etc. compared to the configuration of embodiment 1.

[0120] The OPS control unit 72 may change the amount of rotation of the polarization direction by controlling the first actuator 120 of the first Faraday rotator 91. The OPS control unit 72 may change the amount of rotation of the polarization direction by controlling the second actuator of the second Faraday rotator 202.

[0121] The OPS control unit 72 may determine the amount of rotation of the first Faraday rotator 91 based on the measurement result of the optical sensor 63. The OPS control unit 72 may determine the amount of rotation of the second Faraday rotator 202 based on the measurement result of the optical sensor 63. The OPS control unit 72 may control the amount of rotation of the second Faraday rotator 202 in order to change the waveform of the first half of the pulse waveform of the pulsed laser beam output from the laser device 2D. The OPS control unit 72 may control the amount of rotation of the first Faraday rotator 91 in order to change the waveform of the second half of the pulse waveform of the pulsed laser beam output from the laser device 2D.

[0122] 4.3 Control Flow Examples Fig. 17 is a flowchart showing an example of control processing in the laser device 2D according to embodiment 2. Differences between the flowchart in Fig. 17 and Fig. 7 will be described.

[0123] Steps S71 to S73 in Fig. 17 are the same as the corresponding steps S11 to S13 in Fig. 7. The flowchart in Fig. 17 includes step S74 instead of step S14 in Fig. 7.

[0124] If the determination result in step S73 is Yes, the OPS control unit 72 proceeds to step S74. In step S74, the OPS control unit 72 performs third TIS control. The subroutine of the third TIS control applied in step S74 will be described later with reference to FIG. 18.

[0125] Step S75 after step S74 is the same as step S15 in Fig. 7. After step S75, the OPS control unit 72 ends the flowchart in Fig. 17.

[0126] Fig. 18 is a flowchart showing an example of the third TIS control. The flowchart in Fig. 18 is an example of a subroutine of the processing applied to step S74 in Fig. 17. In Fig. 18, for convenience of illustration, the first Faraday material 95 is referred to as "Faraday material 1," the first magnet 96 as "magnet 1," the second Faraday material 205 as "Faraday material 2," and the second magnet 206 as "magnet 2."

[0127] 18 starts, in step S80, the OPS control unit 72 moves the position of the first Faraday material 95 in the optical axis direction relative to the first magnet 96 to an initial position. Step S80 may be similar to step S30 in FIG.

[0128] Next, in step S81, the OPS control unit 72 moves the position of the second Faraday material 205 in the optical axis direction relative to the second magnet 206 to an initial position. The position of the second Faraday material 205 in the optical axis direction is defined, for example, at the center position of the second Faraday material 205. The initial position of the second Faraday material 205 may be, for example, the center position of the second magnet 206. After step S81, the OPS control unit 72 proceeds to step S82.

[0129] Next, in step S82, the OPS control unit 72 causes the oscillator 10 to output a pulsed laser beam.

[0130] In step S83, the OPS control unit 72 measures the pulse waveform with the optical sensor 63. Then, in step S84, the OPS control unit 72 calculates TIS from the measured pulse waveform and stores the value in association with the positions of the first Faraday material 95 and the second Faraday material 205.

[0131] Thereafter, in step S86, the OPS control unit 72 determines whether the position of the first Faraday material 95 is the movement final position. If the determination result in step S86 is No, the OPS control unit 72 proceeds to step S87, where it moves the first Faraday material 95 in the optical axis direction. Steps S86 and S87 are the same as steps S36 and S37 in FIG. 9. After step S87, the process returns to step S83.

[0132] If the determination result in step S86 is Yes, the OPS control unit 72 proceeds to step S90. In step S90, the OPS control unit 72 determines whether the position of the second Faraday material 205 is the movement final position. If the determination result in step S90 is No, the OPS control unit 72 proceeds to step S91 and moves the first Faraday material 95 to the initial position.

[0133] Then, in step S92, the OPS control unit 72 moves the second Faraday material 205 in the optical axis direction. The amount of movement at this time may be a predetermined amount, such as 0.5 mm. After step S92, the process returns to step S83.

[0134] If the determination result in step S90 is Yes, the OPS control unit 72 proceeds to step S94. In step S94, the OPS control unit 72 stops the output of the pulsed laser light.

[0135] Thereafter, in step S96, the OPS control unit 72 moves the first Faraday material 95 and the second Faraday material 205 to positions that satisfy the target value of TIS (target TIS). Instead of step S96, the OPS control unit 72 may move the first Faraday material 95 and the second Faraday material 205 to positions where the TIS is longest.

[0136] After step S96, the OPS control unit 72 ends the flowchart of FIG. 18 and returns to the flowchart of FIG.

[0137] 17 and 18, table data describing the relationship between the TIS, the position of the first Faraday material 95, and the position of the second Faraday material 205 may be created in advance, as in the example described in FIGS. 10 and 11, and the first Faraday rotator 91 and the second Faraday rotator 202 may be controlled based on this table data.

[0138] 4.4 Effects According to the second embodiment, it is possible to extend the pulse width of the pulsed laser beam and change the pulse waveform without changing the components of the optical system, such as changing the optical circuit length or changing the optical parts. Furthermore, according to the second embodiment, it is possible to meet the target value of the pulse width (TIS) without changing the components of the optical system.

[0139] When the polarization direction of the pulsed laser light incident on the OPS 51 is perpendicular to the transmission axis of the polarizer 53, all components of the pulsed laser light are reflected by the polarizer 53 and propagate through the delay optical path. Then, only the component of the pulsed laser light that is perpendicular to the transmission axis of the polarizer 53 is reflected by the polarizer 53 and passes through the OPS 51. Therefore, the pulsed laser light that has passed through the OPS 51 contains only the component that is perpendicular to the transmission axis of the polarizer 53 (high polarization purity). The configuration of the second embodiment is applicable to applications that require high polarization purity, such as light sources for exposure devices.

[0140] 4.5 Variation 1 4.5.1 Configuration 19 is a schematic diagram showing the configuration of a laser device 2E according to Modification 1 of Embodiment 2. Differences between the configuration shown in FIG. 19 and that shown in FIG. 15 will be described.

[0141] An oscillator 10A of a laser device 2E includes an LNM 11 instead of the rear mirror 17 in Fig. 15. The configuration of the LNM 11 may be the same as that in Fig. 13 .

[0142] 4.5.2 Operation The operation of the oscillator 10A of the laser device 2E is similar to that of the oscillator 10A of Fig. 13. Other operations are similar to those of the laser device 2D according to the second embodiment described with reference to Fig. 15 .

[0143] 4.5.3 Effects According to the laser device 2E according to the first modification of the second embodiment, it is possible to extend the pulse width and change the pulse waveform of pulsed laser light having a narrowed ultraviolet wavelength.

[0144] Furthermore, the laser device 2E can change the narrowband ultraviolet wavelength pulse laser light to any pulse width and pulse waveform without changing the components of the optical system.

[0145] 4.6 Variation 2 4.6.1 Configuration 20 is a schematic diagram showing the configuration of a laser device 2F according to Modification 2 of Embodiment 2. Differences between the configuration shown in FIG. 20 and that shown in FIG. 15 will be described.

[0146] 19 is configured as a MOPO (Master Oscillator Power Oscillator) type system including an oscillation-stage laser 10A and an amplification-stage laser 30. An MO beam steering unit 20 is disposed between the oscillation-stage laser 10A and the amplification-stage laser 30, and a PO beam steering unit 40 is disposed between the amplification-stage laser 30 and the OPS 51.

[0147] The configurations of the oscillation-stage laser 10A, the MO beam steering unit 20, the amplification-stage laser 30, and the PO beam steering unit 40 may be similar to those in FIG.

[0148] 4.6.2 Operation The operation of the laser device 2F is similar to that of the laser device 2C.

[0149] 4.6.3 Effects According to the laser device 2F of the second modification of the second embodiment, it is possible to extend the pulse width and change the pulse waveform of high-energy pulsed laser light with a narrowed ultraviolet wavelength.

[0150] Furthermore, the laser device 2F can change the high-energy pulsed laser light of narrowed ultraviolet wavelength to any pulse width and pulse waveform without changing the components of the optical system.

[0151] 5. Modifications of the laser device The configuration of the oscillation-stage laser 10A is not limited to that shown in Figures 14 and 19, and it is also possible to employ, for example, a solid-state laser system including a semiconductor laser and a wavelength conversion system. The wavelength conversion system may be configured using a nonlinear optical crystal. That is, the oscillation-stage laser is not limited to a gas laser, but may also be an ultraviolet solid-state laser that outputs pulsed laser light with an ultraviolet wavelength. For example, the oscillation-stage laser may be a solid-state laser that oscillates at a wavelength of approximately 193.4 nm, or an ultraviolet solid-state laser that outputs fourth harmonic light of a titanium sapphire laser (wavelength of approximately 774 nm).

[0152] The amplifier is not limited to a configuration having a Fabry-Perot resonator such as the amplification-stage laser 30 shown in Fig. 14, but may also have a configuration having a ring resonator. Furthermore, the amplifier is not limited to a configuration having an optical resonator, but may also be a simple amplifier, for example, an excimer amplifier. The amplifier may also be a multi-pass amplifier such as a three-pass amplifier that amplifies seed light by reflecting it off a cylindrical mirror and passing it through a discharge space three times.

[0153] 6. Manufacturing methods for electronic devices 21 shows a schematic configuration example of an exposure apparatus 80. The exposure apparatus 80 includes an illumination optical system 804 and a projection optical system 806. The laser apparatus 2A generates laser light and outputs the laser light to the exposure apparatus 80. The illumination optical system 804 illuminates a reticle pattern of a reticle (not shown) placed on a reticle stage RT with the laser light incident from the laser apparatus 2A. The projection optical system 806 reduces and projects the laser light that has passed through the reticle, forming an image on a workpiece (not shown) placed on a workpiece table WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0154] Exposure apparatus 80 exposes a workpiece with laser light reflecting a reticle pattern by synchronously translating reticle stage RT and workpiece table WT. After transferring the reticle pattern to a semiconductor wafer through the exposure process described above, a semiconductor device can be manufactured through multiple processes. A semiconductor device is an example of an "electronic device" in this disclosure. Laser apparatus 2B to 2F may also be used, not limited to laser apparatus 2A.

[0155] 7.Other The above description is intended to be illustrative rather than limiting. Thus, it will be apparent to one skilled in the art that modifications can be made to the disclosed embodiments without departing from the scope of the claims. It will also be apparent to one skilled in the art that the disclosed embodiments can be used in combination.

[0156] Terms used throughout this specification and claims should be construed as "open ended" unless expressly stated otherwise. For example, terms such as "comprise," "have," "comprise," and "equip" should be construed as meaning "without excluding the presence of elements other than those listed." In addition, the modifier "a" should be construed as meaning "at least one" or "one or more." In addition, the term "at least one of A, B, and C" should be construed as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C." Furthermore, it should be construed as including combinations of these with elements other than "A," "B," and "C."

Claims

1. An optical pulse stretcher that stretches the pulse width of pulsed laser light, a polarizer that separates a component of the incident pulsed laser light in a specific polarization direction; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; a first Faraday rotator including a first magnet and a first Faraday material, the first Faraday rotator being disposed on an optical path of the delay optical system and rotating the polarization direction of the pulsed laser beam; a first actuator capable of changing an amount of rotation of the polarization direction of the pulsed laser beam in the first Faraday rotator; a processor that controls the first actuator; Equipped with Optical pulse stretcher.

2. 10. An optical pulse stretcher according to claim 1, the first actuator is a first moving mechanism that changes the position of the first Faraday material relative to the first magnet in the optical axis direction of the pulsed laser light; Optical pulse stretcher.

3. An optical pulse stretcher for stretching the pulse width of pulsed laser light, comprising: a polarizer that separates a component of the incident pulsed laser light in a specific polarization direction; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; a first Faraday rotator including a first magnet and a first Faraday material, the first Faraday rotator being disposed on an optical path of the delay optical system and rotating the polarization direction of the pulsed laser beam; a second Faraday rotator including a second magnet and a second Faraday material, which rotates the polarization direction of the pulsed laser light incident on the polarizer; 1. An optical pulse stretcher comprising:

4. 4. An optical pulse stretcher according to claim 3, a first actuator capable of changing an amount of rotation of the polarization direction of the pulsed laser beam in the first Faraday rotator; a second actuator capable of changing an amount of rotation of the polarization direction of the pulsed laser beam in the second Faraday rotator; a processor that controls the first actuator and the second actuator; an optical pulse stretcher further comprising:

5. 5. An optical pulse stretcher according to claim 4, the first actuator is a first moving mechanism that changes the position of the first Faraday material relative to the first magnet in the optical axis direction of the pulsed laser beam, the second actuator is a second moving mechanism that changes the position of the second Faraday material relative to the second magnet in the optical axis direction of the pulsed laser light; Optical pulse stretcher.

6. An optical pulse stretcher for stretching the pulse width of pulsed laser light, comprising: a polarizer that separates a component of the incident pulsed laser light in a specific polarization direction; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; a first Faraday rotator including a first magnet and a first Faraday material, the first Faraday rotator being disposed on an optical path of the delay optical system and rotating the polarization direction of the pulsed laser beam; the polarization direction of the pulsed laser light incident on the optical pulse stretcher and the transmission axis of the polarizer are orthogonal to each other; Optical pulse stretcher.

7. 10. An optical pulse stretcher according to claim 1, the plurality of mirrors includes four concave mirrors; Optical pulse stretcher.

8. 4. An optical pulse stretcher according to claim 3, Each of the first Faraday material and the second Faraday material is calcium fluoride or synthetic quartz. Optical pulse stretcher.

9. an oscillator that outputs pulsed laser light; an optical pulse stretcher that stretches the pulse width of the pulsed laser light, The optical pulse stretcher a polarizer that separates a specific polarization direction of the incident pulsed laser light; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; a first Faraday rotator including a first magnet and a first Faraday material, the first Faraday rotator being disposed on an optical path of the delay optical system and rotating the polarization direction of the pulsed laser beam; A laser device comprising: a first actuator capable of changing an amount of rotation of the polarization direction of the pulsed laser beam; a processor that controls the first actuator; A laser device comprising:

10. 10. The laser device according to claim 9, the first actuator is a first moving mechanism that changes the position of the first Faraday material relative to the first magnet in the optical axis direction of the pulsed laser light; Laser device.

11. 10. The laser device according to claim 9, an optical sensor that measures the pulse waveform of the pulsed laser light that has passed through the optical pulse stretcher; the processor calculates a pulse width from the pulse waveform and controls the first actuator so that the pulse width is equal to or greater than a target value. Laser device.

12. 10. The laser device according to claim 9, the processor controls the first actuator using table data indicating a relationship between a pulse width of the pulsed laser light that has passed through the optical pulse stretcher and a control amount of the first actuator so that the pulse width becomes equal to or greater than a target value. Laser device.

13. An oscillator that outputs pulsed laser light; an optical pulse stretcher that stretches the pulse width of the pulsed laser light, The optical pulse stretcher a polarizer that separates a specific polarization direction of the incident pulsed laser light; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; a first Faraday rotator including a first magnet and a first Faraday material, the first Faraday rotator being disposed on an optical path of the delay optical system and rotating the polarization direction of the pulsed laser beam; A laser device comprising: the polarization direction of the pulsed laser light incident on the optical pulse stretcher and the transmission axis of the polarizer are orthogonal to each other; Laser device.

14. 10. The laser device according to claim 9, the oscillator includes a line-narrowing optical system that narrows the spectral line width of the pulsed laser light having an ultraviolet wavelength. Laser device.

15. 10. The laser device according to claim 9, The oscillator comprises: an oscillation stage laser that outputs a first pulsed laser beam having an ultraviolet wavelength; an amplifier that amplifies and outputs the first pulsed laser light output from the oscillation-stage laser, Laser device.

16. An oscillator that outputs pulsed laser light; an optical pulse stretcher that stretches the pulse width of the pulsed laser light, The optical pulse stretcher a polarizer that separates a specific polarization direction of the incident pulsed laser light; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; a first Faraday rotator including a first magnet and a first Faraday material, the first Faraday rotator being disposed on an optical path of the delay optical system and rotating the polarization direction of the pulsed laser beam; A laser device comprising: a second Faraday rotator including a second magnet and a second Faraday material, which rotates the polarization direction of the pulsed laser light incident on the optical pulse stretcher; Laser device.

17. 17. The laser device of claim 16, a first actuator capable of changing an amount of rotation of the polarization direction of the pulsed laser beam in the first Faraday rotator; a second actuator capable of changing an amount of rotation of the polarization direction of the pulsed laser beam in the second Faraday rotator; a processor that controls the first actuator and the second actuator; The laser device further comprises:

18. A method for manufacturing an electronic device, comprising: an oscillator that outputs pulsed laser light; an optical pulse stretcher that stretches the pulse width of the pulsed laser light, The optical pulse stretcher a polarizer that separates a specific polarization direction of the incident pulsed laser light; a delay optical system including a plurality of mirrors through which the pulsed laser light reflected by or transmitted through the polarizer propagates; a first Faraday rotator including a first magnet and a first Faraday material, the first Faraday rotator being disposed on an optical path of the delay optical system and rotating the polarization direction of the pulsed laser beam; a first actuator capable of changing an amount of rotation of the polarization direction of the pulsed laser beam in the first Faraday rotator; generating the laser light having the extended pulse width by a laser device including a processor that controls the first actuator; outputting the laser light to an exposure device; A method for manufacturing an electronic device, comprising exposing a photosensitive substrate to the laser light in the exposure apparatus to manufacture the electronic device.

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