Pulse width extension system, laser apparatus, and method of manufacturing electronic device

Abstract

To provide a pulse width extension system capable of completing alignment adjustment of an optical axis in a short time.SOLUTION: The pulse width stretching system includes a pulse width stretching optical system configured to include a beam splitter and a plurality of mirrors, a case that houses the pulse width stretching optical system, at least one target configured such that a portion irradiated with a pulsed laser beam can be determined, and a target moving mechanism that enables the at least one target to be disposed in an optical path including the pulse width stretching optical system and enables the at least one target to be retracted from the optical path.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a pulse stretching system, a laser apparatus, and a method for manufacturing an electronic device. [Background technology]

[0002] In recent years, semiconductor exposure devices have been required to improve their resolution in response to the miniaturization and high integration of semiconductor integrated circuits. To this end, the wavelength of light emitted from exposure light sources has been shortened. For example, KrF excimer laser devices, which output laser light with a wavelength of approximately 248 nm, and ArF excimer laser devices, which 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. 1,179,9261 [Patent Document 2] International Publication No. 2022 / 132448 [Patent Document 3] Summary of the specification of U.S. Patent Application Publication No. 2022 / 0393420

[0005] A pulse width stretching system according to one aspect of the present disclosure is a pulse width stretching system that stretches the pulse width of an incident pulsed laser beam and outputs the stretched pulsed laser beam, and includes: a pulse width stretching optical system including a beam splitter and a plurality of mirrors; a case that houses the pulse width stretching optical system; at least one target configured to enable identification of a portion irradiated with the pulsed laser beam; and a target moving mechanism that enables placement of the at least one target in an optical path including the pulse width stretching optical system and retraction of the at least one target from the optical path.

[0006] A laser device according to one aspect of the present disclosure includes a laser oscillator that outputs pulsed laser light and a pulse stretching system that stretches the pulse width of the incident pulsed laser light and outputs the pulsed laser light, wherein the pulse stretching system includes a pulse stretching optical system including a beam splitter and a plurality of mirrors, a case that houses the pulse stretching optical system, at least one target configured so that a portion irradiated with the pulsed laser light can be identified, and a target moving mechanism that enables the at least one target to be placed in an optical path including the pulse stretching optical system and the at least one target to be retracted from the optical path.

[0007] A method for manufacturing an electronic device according to one aspect of the present disclosure is a method for manufacturing an electronic device, the method comprising: generating pulsed laser light whose pulse width has been stretched by a laser apparatus including a laser oscillator that outputs pulsed laser light and a pulse stretching system that stretches the pulse width of the incident pulsed laser light and outputs the pulsed laser light; the pulse stretching system including a pulse stretching optical system including a beam splitter and a plurality of mirrors, a case that houses the pulse stretching optical system, at least one target configured to enable identification of a portion irradiated with the pulsed laser light, and a target moving mechanism that enables placement of the at least one target in an optical path including the pulse stretching optical system and retraction of the at least one target from the optical path; outputting the pulsed laser light to an exposure apparatus; and exposing a photosensitive substrate in the exposure apparatus with the pulsed 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 front view schematically showing the configuration of a laser device according to a comparative example. [Figure 2] FIG. 2 is a view of the L-OPS as seen from the V-axis direction. [Figure 3] FIG. 3 is a view of the pulse stretching system seen from diagonally above. [Figure 4] FIG. 4 is a view of the pulse width stretching system in which the first and second adjustment jigs are arranged, viewed obliquely from above. [Figure 5] FIG. 5 is a view of the pulse width expansion system according to the first embodiment, viewed obliquely from above. [Figure 6] FIG. 6 is a diagram showing the configuration of the target moving mechanism according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing the configuration of the target moving mechanism according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating alignment adjustment according to the first embodiment. [Figure 9] FIG. 9 is a diagram showing a camera that captures an image of the first target and the second target. [Figure 10] FIG. 10 is a diagram showing the configuration of a target moving mechanism according to a first modified example. [Figure 11] FIG. 11 is a diagram showing the configuration of a target moving mechanism according to a first modified example. [Figure 12] FIG. 12 is a diagram showing the configuration of a target moving mechanism according to the second modified example. [Figure 13] FIG. 13 is a diagram showing the configuration of a target moving mechanism according to the second modified example. [Figure 14] FIG. 14 is a diagram showing first to fifth modified examples of the first target and the second target. [Figure 15] FIG. 15 is a view of the pulse width stretching system according to the second embodiment, viewed obliquely from above. [Figure 16] FIG. 16 is a view of the pulse width stretching system according to the third embodiment, viewed obliquely from above. [Figure 17] FIG. 17 is a diagram illustrating alignment adjustment of the first optical axis according to the third embodiment. [Figure 18] FIG. 18 is a diagram illustrating alignment adjustment of the second optical axis according to the third embodiment. [Figure 19] FIG. 19 is a diagram showing first to fifth modified examples of the first target and the second target. [Figure 20] FIG. 20 is a diagram showing first to fifth modified examples of the first target and the second target. [Figure 21] FIG. 21 is a diagram schematically showing an example of the configuration of an exposure apparatus. Embodiment

[0009] <Contents> 1. Comparative Example 1.1 Configuration 1.1.2 Laser equipment 1.1.3 Pulse width stretcher system 1.2 Operation 1.3 Challenges 2. First embodiment 2.1 Configuration 2.2 Operation 2.3 Effects 2.4 Modified target movement mechanism 2.5 Target Variations 3. Second embodiment 3.1 Configuration 3.2 Operation 3.3 Effects 4. Third embodiment 4.1 Configuration 4.2 Operation 4.3 Effects 4.4 Target Variations 5. Modifications of the First to Third Embodiments 6. Manufacturing method of electronic devices

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

[0011] 1. Comparative Example 1.1 Configuration 1.1.2 Laser equipment 1 shows a schematic configuration example of a laser device 2 according to a comparative example. The comparative example of the present disclosure is a configuration that the applicant recognizes as being known only by the applicant, and is not a publicly known example that the applicant acknowledges.

[0012] 1, the height direction of the laser device 2 is defined as the V-axis direction, the length direction as the Z-axis direction, and the depth direction as the H-axis direction. For example, the V-axis direction is parallel to the direction of gravity. The Z-axis direction is parallel to the emission direction of the pulsed laser light PL emitted from the laser device 2.

[0013] The laser device 2 is a narrow-band gas laser device including a master oscillator (MO) 10, an MO beam steering unit 20, a power oscillator (PO) 30, a PO beam steering unit 40, and an optical pulse stretcher (OPS) 50. The master oscillator 10 is an example of a "laser oscillator" according to the technology of the present disclosure.

[0014] The laser device 2 also includes a long optical pulse stretcher 60 (hereinafter referred to as "L-OPS 60"). The PO beam steering unit 40 and the L-OPS 60 constitute a "pulse width stretching system" according to the technology of the present disclosure. In the present disclosure, the pulse width refers to the temporal width of a pulse. The L-OPS 60 is an example of a "pulse width stretching optical system" according to the technology of the present disclosure.

[0015] The master oscillator 10 includes a line narrowing module (LNM) 11 , a chamber 14 , and an output coupling mirror (OC) 17 .

[0016] The LNM 11 includes a prism beam expander 12 for narrowing the spectral linewidth, and a grating 13. The prism beam expander 12 and the grating 13 are arranged in a Littrow configuration so that the angle of incidence and the angle of diffraction match.

[0017] The output coupling mirror 17 is a reflecting mirror with a reflectance in the range of 40% to 60%. The output coupling mirror 17 and the LNM 11 are arranged to form an optical resonator.

[0018] The chamber 14 is disposed on the optical path of the optical resonator. The chamber 14 includes a pair of discharge electrodes 15a, 15b and two windows 16a, 16b through which the pulsed laser light PL passes. The chamber 14 contains an excimer laser gas therein. 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 MO beam steering unit 20 includes a high-reflection mirror 21a and a high-reflection mirror 21b. The high-reflection mirrors 21a and 21b are arranged so that the pulsed laser light PL output from the master oscillator 10 is incident on the power oscillator 30. The high-reflection mirror in this disclosure is a flat mirror in which a high-reflection film is formed on the surface of a substrate made of, for example, synthetic quartz or calcium fluoride (CaF2). The high-reflection film is a dielectric multilayer film, for example, a film containing a fluoride.

[0020] The power oscillator 30 includes a rear mirror 31, a chamber 32, and an output coupling mirror 35. The rear mirror 31 and the output coupling mirror 35 are arranged to form an optical resonator.

[0021] The chamber 32 is disposed on the optical path of the optical resonator. The chamber 32 may have a configuration similar to that of the chamber 14 of the master oscillator 10. That is, the chamber 32 includes a pair of discharge electrodes 33a, 33b and two windows 34a, 34b through which the pulsed laser light PL passes. The chamber 32 contains an excimer laser gas therein.

[0022] The rear mirror 31 is a reflective mirror with a reflectance in the range of 50% to 90%. The output coupling mirror 35 is a reflective mirror with a reflectance in the range of 10% to 30%.

[0023] The PO beam steering unit 40 includes a first steering section 41 and a second steering section 42 for exchanging light with the L-OPS 60. The PO beam steering unit 40 is an example of a “steering device” according to the technology of the present disclosure.

[0024] The first steering unit 41 is composed of a high-reflection mirror 41a and a high-reflection mirror 41b. The high-reflection mirror 41a is arranged to reflect the pulsed laser light PL output from the power oscillator 30 and make it incident on the high-reflection mirror 41b. The high-reflection mirror 41b is arranged to reflect the pulsed laser light PL reflected by the high-reflection mirror 41a and make it incident on the L-OPS 60. The high-reflection mirrors 41a and 41b are an example of the "multiple steering mirrors" according to the technology of the present disclosure.

[0025] The second steering unit 42 is composed of a high-reflection mirror 42a and a high-reflection mirror 42b. The high-reflection mirror 42a is arranged to reflect the pulsed laser beam PL emitted from the L-OPS 60 and make it incident on the high-reflection mirror 42b. The high-reflection mirror 42b is arranged to reflect the pulsed laser beam PL reflected by the high-reflection mirror 42a and make it incident on the OPS 50.

[0026] As will be described in detail later, the L-OPS 60 includes at least one beam splitter and a plurality of high-reflection mirrors. The L-OPS 60 is disposed on the ceiling side of the laser device 2.

[0027] The OPS 50 includes a beam splitter 52 and four concave mirrors 54a to 54d. The beam splitter 52 is disposed on the optical path of the pulsed laser beam PL output from the PO beam steering unit 40. The beam splitter 52 is a partial reflection mirror that transmits a portion of the incident pulsed laser beam PL and reflects the other portion. The reflectance of the beam splitter 52 is preferably within a range of 40% to 70%, and more preferably approximately 60%.

[0028] The four concave mirrors 54a to 54d form a loop optical path that circulates a portion of the pulsed laser light PL that is incident from the PO beam steering unit 40 and reflected by the beam splitter 52, and returns it to the beam splitter 52. The portion of the pulsed laser light PL that is incident from the PO beam steering unit 40 and transmitted through the beam splitter 52 and the portion of the pulsed laser light PL that has circulated around the loop optical path at least once are superimposed on each other, and are output from the OPS 50.

[0029] The OPS 50 is disposed at the final stage of the laser device 2, and causes the laser device 2 to output pulsed laser light PL whose pulse width has been expanded.

[0030] The OPS 50 may be configured to include a beam splitter and a plurality of highly reflective mirrors.

[0031] The laser device 2 may be covered by a cover panel (not shown) that can be removed for maintenance or the like.

[0032] 1.1.3 Pulse width stretcher system Next, the configuration of a pulse stretching system according to a comparative example will be described. Fig. 2 is a diagram of the L-OPS 60 as seen from the V-axis direction. Fig. 3 is a diagram of the pulse stretching system as seen from diagonally above.

[0033] L-OPS 60 includes a beam splitter 61, six concave mirrors 62a to 62f, a beam splitter 63, four concave mirrors 64a to 64d, and high-reflection mirrors 65 to 68. L-OPS 60 is housed in a case 69. Concave mirrors 62a to 62f and concave mirrors 64a to 64d are examples of the "plurality of mirrors" according to the technology of the present disclosure.

[0034] The case 69 is a rectangular box with its longitudinal direction in the Z-axis direction. The case 69 also has a maintenance face 69a. Of the two faces facing each other in the H-axis direction, the maintenance face 69a is the face on which a cover panel (not shown) opens for maintenance or the like. The inside of the case 69 is purged with a purge gas, which is an inert gas. For this purpose, a purge gas supply source (not shown) may be connected to the case 69.

[0035] Further, an opening 69b for allowing the pulsed laser beam PL emitted from the first steering unit 41 to enter the case 69 and an opening 69c for allowing the pulsed laser beam PL to be emitted toward the second steering unit 42 are provided on the bottom surface of the case 69. The openings 69b and 69c are each connected to an optical path tube (not shown) that is purged with a purge gas.

[0036] 3 indicates the beam profile of the pulsed laser light PL. The first steering unit 41 is configured to rotate the beam profile BP of the incident pulsed laser light PL, which is long in the V-axis direction, and emit the pulsed laser light PL having a beam profile BP that is long in the H-axis direction. The second steering unit 42 is configured to rotate the beam profile BP of the incident pulsed laser light PL, which is long in the H-axis direction, and emit the pulsed laser light PL having a beam profile BP that is long in the V-axis direction.

[0037] The beam splitter 61 is disposed on the optical path of the pulsed laser beam PL emitted from the first steering unit 41. The beam splitter 61 is a partial reflection mirror that transmits a portion of the incident pulsed laser beam PL and reflects the other portion. The reflectance of the beam splitter 61 is preferably within a range of 40% to 70%, and more preferably approximately 60%.

[0038] The six concave mirrors 62a to 62f configure a first loop optical path along which a portion of the pulsed laser beam PL, which enters from the first steering unit 41 through the opening 69b and is reflected by the beam splitter 61, is circulated and returned to the beam splitter 61. In FIG. 2, the first loop optical path is indicated by a dashed line. The portion of the pulsed laser beam PL, which enters from the first steering unit 41 and is transmitted through the beam splitter 61, and the portion of the pulsed laser beam PL, which has circulated around the first loop optical path at least once, are superimposed on each other and output toward the high-reflection mirror 66.

[0039] High-reflection mirror 65 is arranged to reflect the pulsed laser beam PL, the pulse width of which has been extended by the first loop optical path, and cause it to be incident on high-reflection mirror 66. High-reflection mirror 66 is arranged to reflect the pulsed laser beam PL reflected by high-reflection mirror 65, and cause it to be incident on high-reflection mirror 67. High-reflection mirror 67 is arranged to reflect the pulsed laser beam PL reflected by high-reflection mirror 65, and cause it to be incident on high-reflection mirror 68.

[0040] The beam splitter 63 is disposed on the optical path of the pulsed laser beam PL reflected by the high-reflection mirror 67. The beam splitter 63 is a partial reflection mirror that transmits a portion of the incident pulsed laser beam PL and reflects the other portion. The reflectance of the beam splitter 63 is preferably within a range of 40% to 70%, and more preferably approximately 60%.

[0041] The four concave mirrors 64a to 64d configure a second loop optical path that circulates a portion of the pulsed laser beam PL that is incident from the high-reflection mirror 67 and reflected by the beam splitter 63, and returns it to the beam splitter 63. In Fig. 2, the second loop optical path is indicated by a solid line. The portion of the pulsed laser beam PL that is incident from the high-reflection mirror 67 and transmitted through the beam splitter 63 and the portion of the pulsed laser beam PL that has circulated around the second loop optical path at least once are superimposed on each other, and are output toward the high-reflection mirror 68.

[0042] The high-reflection mirror 68 is arranged to reflect the pulsed laser light PL, the pulse width of which has been further extended by the second loop optical path, and make it incident on the high-reflection mirror 42a of the second steering unit 42 via the opening 69c.

[0043] The concave mirrors 62a to 62f and the concave mirrors 64a to 64d are arranged at both ends in the Z-axis direction, which is the longitudinal direction of the case 69, so that the first loop optical path and the second loop optical path overlap in the V-axis direction.

[0044] The high-reflection mirrors 66 and 67 are arranged on the maintenance face 69a side of the case 69, and the high-reflection mirrors 65 and 68 are arranged on the opposite side of the maintenance face 69a. As a result, the optical path between the high-reflection mirror 65 and the first steering unit 41 and the optical path between the high-reflection mirror 68 and the second steering unit 42 are configured on the opposite side of the maintenance face 69a.

[0045] 1.2 Operation Next, the operation of the laser device 2 according to the comparative example will be described. When a discharge occurs in the chamber 14 of the master oscillator 10, the laser gas is excited, and pulsed laser light PL, which has been narrowed in line by an optical resonator formed by the output coupling mirror 17 and the LNM 11, is output from the output coupling mirror 17. This pulsed laser light PL is made incident on the rear mirror 31 of the power oscillator 30 as seed light by the MO beam steering unit 20.

[0046] A discharge occurs in chamber 32 in synchronization with the incidence of the seed light that has passed through rear mirror 31. As a result, the laser gas is excited, the seed light is amplified by a Fabry-Perot optical resonator formed by output coupling mirror 35 and rear mirror 31, and the amplified pulsed laser light PL is output from output coupling mirror 35. The pulsed laser light PL output from output coupling mirror 35 enters PO beam steering unit 40, and its traveling direction is changed by first steering section 41 before it enters L-OPS 60.

[0047] The pulsed laser light PL incident on the L-OPS 60 has its pulse width expanded and returns to the PO beam steering unit 40 , where its traveling direction is changed by the second steering section 42 and it is incident on the OPS 50 .

[0048] The pulsed laser light PL incident on the OPS 50 has its pulse width further expanded and is output from the laser device 2. The pulsed laser light PL may be output from the laser device 2 via a monitor module (not shown) that measures pulse energy, spectral linewidth, wavelength, etc. The pulsed laser light PL output from the laser device 2 is incident on an external device such as an exposure device.

[0049] By extending the pulse width of the pulsed laser light PL using the L-OPS 60 and OPS 50, the coherence is reduced, which in turn suppresses the occurrence of speckle. Speckle is a bright and dark spot that occurs due to interference when laser light is scattered in a random medium.

[0050] 1.3 Challenges Next, a problem with the laser device 2 according to the comparative example will be described. In the laser device 2 according to the comparative example, if an abnormality occurs in the laser performance, an operator may check the alignment of the optical axis through which the pulsed laser beam PL is incident on the L-OPS 60 to identify the cause. If there is a deviation in the alignment, the operator needs to remove a cover panel or the like from the case 69 and install at least one adjustment jig inside the case 69. For example, the operator performs alignment adjustment using a first adjustment jig 70 and a second adjustment jig 80 shown in FIG. 4. The second adjustment jig 80 is installed inside the case 69 after removing the cover panel from the case 69. Hereinafter, when the term "alignment adjustment" is used simply, it also includes checking the alignment. Furthermore, alignment adjustment includes at least one of adjusting the position and angle of the optical axis.

[0051] The first adjustment jig 70 includes a first target 71 and a camera 72. The first target 71 is a circular fluorescent plate with a pinhole 71a formed in its center, and a portion irradiated with the pulsed laser beam PL emits visible fluorescent light. The first target 71 is positioned so that the design optical axis on the incident side of the high-reflection mirror 41a passes through the pinhole 71a. The camera 72 is positioned opposite the first target 71 across the high-reflection mirror 41a. The high-reflection mirror 41a has a property of transmitting visible light. The camera 72 receives the fluorescent light emitted from the first target 71 via the high-reflection mirror 41a, thereby capturing an image of the first target 71. The pinhole 71a is an example of a "first passage hole" according to the technology of the present disclosure.

[0052] With the laser device 2 emitting pulsed laser light PL, the operator observes the image captured by the camera 72. If the center of the irradiation area is deviated from the pinhole 71a, the operator adjusts the first steering unit 41 so that the center of the irradiation area coincides with the pinhole 71a. Specifically, the operator adjusts the angles of the high-reflection mirrors 41a and 41b. In this manner, the first adjustment jig 70 is used to adjust the position of the beam, i.e., the position of the optical axis.

[0053] The second adjustment jig 80 includes a second target 81 and a camera 82. The second target 81 is a circular fluorescent plate, and a portion irradiated with the pulsed laser beam PL emits visible fluorescent light. The second target 81 is positioned so that the design optical axis on the exit side of the high-reflection mirror 65 passes through the center of the second target 81. In this comparative example, the center of the second target 81 is the target position where a portion of the pulsed laser beam PL that has passed through the pinhole 71a is irradiated. The camera 82 is positioned between the high-reflection mirror 65 and the high-reflection mirror 66, at a position where it can capture an image of the second target 81 from the exit side. The operator removes the cover panel of the case 69 and positions the second target 81 and the camera 82.

[0054] With the laser device 2 emitting the pulsed laser beam PL, the operator observes the image captured by the camera 82. If the position irradiated with part of the pulsed laser beam PL that has passed through the pinhole 71a of the first target 71 is deviated from the target position of the second target 81, the operator adjusts the first steering unit 41 so that the irradiation position coincides with the target position. Specifically, the operator adjusts the angles of the high-reflection mirrors 41a and 41b. In this manner, the second adjustment jig 80 is used to adjust the pointing angle of the beam, i.e., adjust the angle of the optical axis.

[0055] As described above, in the alignment adjustment of the optical axis, the optical axis is adjusted so that it passes through two predetermined points, specifically, the pinhole 71a of the first target 71 and the target position of the second target 81.

[0056] However, the above-described alignment adjustment requires removing the cover panel, placing the second adjustment jig 80 inside the case 69, and then reinstalling the cover panel. Including this work, the alignment adjustment may take several hours. Furthermore, it takes even more time to reseal the unsealed case 69 and purge it with purge gas. As a result, the work time required for the alignment adjustment is long, and may exceed the upper limit of the work time required at the factory where the laser device 2 is installed.

[0057] Therefore, there is a demand for a pulse width stretching system that can complete the alignment adjustment of the optical axis in a short time.

[0058] 2. First embodiment A laser device 2 according to a first embodiment of the present disclosure will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0059] 2.1 Configuration The laser device 2 according to this embodiment has the same configuration as the laser device 2 according to the comparative example, except for the pulse width stretching system.

[0060] 5 is a view of the pulse width expansion system according to the first embodiment as viewed from diagonally above. In this embodiment, a first target 71 and a second target 81 used for alignment adjustment are arranged in a case 69 so as to be retractable from the optical path of the pulsed laser beam PL. The optical system constituting the L-OPS 60 is the same as that in the comparative example.

[0061] The configurations of the first target 71 and the second target 81 are the same as those of the comparative example. The first target 71 and the second target 81 are preferably made of synthetic quartz, and more preferably made of borosilicate crown glass commonly known as BK7.

[0062] In the present embodiment, the first target 71 is arranged in the optical path between the high-reflection mirror 65 and the high-reflection mirror 66 so as to be able to be retracted. When the first target 71 is arranged in the optical path, the first target 71 is arranged so that the designed optical axis on the output side of the high-reflection mirror 65 passes through the pinhole 71a. Furthermore, in the present embodiment, the second target 81 is arranged in the optical path between the high-reflection mirror 67 and the high-reflection mirror 68 so as to be able to be retracted. When the second target 81 is arranged in the optical path, the second target 81 is arranged so that the designed optical axis on the output side of the high-reflection mirror 67 passes through the center of the second target 81. In this way, in the present embodiment, as in the comparative example, the first target 71 is arranged on the upstream side of the optical path of the pulsed laser beam PL, and the second target 81 is arranged on the downstream side.

[0063] In this embodiment, a window 69d is provided in the case 69, which allows the first target 71 and the second target 81 to be observed from outside the case 69. For example, the window 69d is arranged on the maintenance face 69a side, and the high-reflection mirrors 65 and 68 are provided in a region corresponding to the area between the high-reflection mirror 66 and the high-reflection mirror 67 on the maintenance face 69a.

[0064] Figures 6 and 7 show the configuration of the target moving mechanism according to the first embodiment. Figure 6 shows the state of the target moving mechanism when the target is not in use. Figure 7 shows the state of the target moving mechanism when the target is in use. Figures 6(A) and 7(A) are views of the target moving mechanism as seen from the V-axis direction. Figures 6(B) and 7(B) are views of the target moving mechanism as seen from the Z-axis direction. Figures 6(C) and 7(C) are views of the target moving mechanism as seen from the H-axis direction.

[0065] Not using a target means retracting the first target 71 and the second target 81 from the optical path. Using a target means placing the first target 71 and the second target 81 in the optical path. The target movement mechanism is a mechanism that enables the first target 71 and the second target 81 to be placed in the optical path and the first target 71 and the second target 81 to be retracted from the optical path.

[0066] In this embodiment, the target movement mechanism includes a link mechanism 90. The link mechanism 90 is made up of a plurality of connected rod-shaped members. The link mechanism 90 may be made up of gears such as bevel gears, or may be made up of other power transmission mechanisms. One end of the link mechanism 90 is connected to a lever 91 provided on the maintenance surface 69a. The link mechanism 90 is configured to rotate in response to an operator rotating the lever 91. One end of the link mechanism 90 is joined to a first connecting portion 92a and a second connecting portion 92b.

[0067] The first connection portion 92a is fixed to a target holder 93a that holds the first target 71. The first connection portion 92a is rotatably supported by a first support portion 95a that is arranged on a substrate 94. The second connection portion 92b is fixed to a target holder 93b that holds the second target 81. The second connection portion 92b is rotatably supported by a second support portion 95b that is arranged on the substrate 94.

[0068] The link mechanism 90 transmits a driving force corresponding to the rotational operation of the lever 91 to the target holders 93a, 93b, thereby moving the first target 71 and the second target 81 between a tilted state and an upright state. As shown in Fig. 6, the first target 71 and the second target 81 are retracted from the optical path when they are in the tilted state. As shown in Fig. 7, the first target 71 and the second target 81 are positioned in the optical path when they are in the upright state.

[0069] The window 69d is covered with a window plate 96 made of glass, acrylic, or the like that transmits visible light. A lid 97 made of metal or the like that blocks ultraviolet light is removably attached to the maintenance face 69a with a plurality of bolts 97a so as to cover the window 69d. Fig. 6 shows the state in which the lid 97 is attached. Fig. 7 shows the state in which the lid 97 is removed.

[0070] 2.2 Operation In this embodiment, before operating the laser device 2, the first target 71 and the second target 81 are placed in a tilted state by operating the lever 91, and a lid 97 is attached to cover the window 69d. The operation of the laser device 2 according to this embodiment regarding the output of the pulsed laser light PL is the same as that of the comparative example.

[0071] In this embodiment, if an abnormality occurs in the laser performance, the operator operates lever 91 to raise first target 71 and second target 81 and place them in the optical path in order to check the alignment of the optical axis. In addition, the operator can remove lid 97 to observe first target 71 and second target 81 from outside case 69 through window 69d.

[0072] Next, the operator causes the laser device 2 to output the pulsed laser beam PL, and visually checks the position of the irradiation area of ​​the pulsed laser beam PL irradiating the first target 71, as shown in FIG. 8. If the center of the irradiation area does not coincide with the pinhole 71a, the operator adjusts the first steering unit 41 so that the center coincides with the pinhole 71a. Specifically, the operator adjusts the angles of the high-reflection mirrors 41a and 41b. In this manner, the position of the optical axis is adjusted.

[0073] Next, the worker visually checks the position on the second target 81 where part of the pulsed laser beam PL that has passed through the pinhole 71a of the first target 71 is irradiated. If the irradiation position does not coincide with the target position on the second target 81, the worker adjusts the first steering unit 41 so that the irradiation position coincides with the target position on the second target 81. Specifically, the worker adjusts the angles of the high-reflection mirrors 41a and 41b. In this manner, the angle of the optical axis is adjusted.

[0074] When the alignment adjustment is completed, the operator operates the lever 91 to lay down the first target 71 and the second target 81, thereby retracting them from the optical path. The operator also attaches the lid 97 to cover the window 69d.

[0075] 9, the worker may attach camera 100 at a position where it is possible to capture images of first target 71 and second target 81 through window 69d, and perform the above-mentioned alignment adjustment while observing the images captured by camera 100. In this case, the worker removes camera 100 after completing the alignment adjustment. Camera 100 may be any imaging device that can receive fluorescence emitted by first target 71 and second target 81.

[0076] 2.3 Effects In this embodiment, the first target 71 and the second target 81 are arranged in the case 69 by the target moving mechanism so that they can be retracted from the optical path of the pulsed laser light PL. Therefore, when performing alignment adjustment of the optical axis, it is not necessary to remove the cover panel and attach an adjustment jig inside the case 69, or to remove the adjustment jig and attach the cover panel to the case 69 after the alignment adjustment. Furthermore, because the case 69 remains sealed during alignment adjustment, it is not necessary to purge the inside of the case 69 again with purge gas. Therefore, according to this embodiment, it is possible to complete the alignment adjustment in a short time.

[0077] 2.4 Modified target movement mechanism Next, various modified examples of the target movement mechanism will be described. In the first embodiment, the target movement mechanism is a mechanism that moves the first target 71 and the second target 81 away from the optical path by tilting them, but various modifications are possible.

[0078] 10 and 11 show the configuration of a target moving mechanism according to a first modified example. Fig. 10 shows the state of the target moving mechanism when a target is in use. Fig. 11 shows the state of the target moving mechanism when a target is not in use.

[0079] In this modified example, the target moving mechanism includes a linear guide 101. The linear guide 101 is fixed on a substrate 94. The first target 71 and the second target 81 are slidably held by the linear guide 101 via a holder 102.

[0080] Furthermore, in this modified example, an actuator 103 is provided that drives the linear guide 101 to slide the first target 71 and the second target 81. An operating unit (not shown) for operating the actuator 103 is provided outside the case 69, and the operator slides the first target 71 and the second target 81 by operating the operating unit.

[0081] When adjusting the alignment of the optical axis, the operator operates the operation unit to place the first target 71 and the second target 81 on the optical path as shown in Fig. 10. After completing the alignment adjustment, the operator operates the operation unit to move the first target 71 and the second target 81 out of the optical path as shown in Fig. 11.

[0082] The target moving mechanism may be configured so that the first target 71 and the second target 81 can be slid by manual operation by an operator, instead of by the actuator 103.

[0083] 12 and 13 show the configuration of a target moving mechanism according to a second modified example. Fig. 12 shows the state of the target moving mechanism when a target is used. Fig. 13 shows the state of the target moving mechanism when a target is not used.

[0084] In this modified example, the target moving mechanism includes rotating arms 111 and 112. The first target 71 is rotatably held by the rotating arm 111 via a target holder 93a. The second target 81 is rotatably held by the rotating arm 112 via a target holder 93b.

[0085] Furthermore, this modified example is provided with an actuator 110 that rotates the first target 71 and the second target 81 by driving rotating arms 111 and 112. The rotation axes of the rotating arms 111 and 112 are parallel to the optical axis. The rotating directions of the rotating arms 111 and 112 are opposite to each other. An operating unit (not shown) for operating the actuator 110 is provided on the outside of the case 69, and the operator rotates the first target 71 and the second target 81 by operating the operating unit.

[0086] When adjusting the alignment of the optical axis, the operator operates the operation unit to place the first target 71 and the second target 81 on the optical path as shown in Fig. 12. After completing the alignment adjustment, the operator operates the operation unit to move the first target 71 and the second target 81 out of the optical path as shown in Fig. 13.

[0087] The target moving mechanism may be configured so that the first target 71 and the second target 81 can be rotated by manual operation by an operator, instead of by the actuator 110.

[0088] 2.5 Target Variations Next, various modifications of the first target 71 and the second target 81 according to the first embodiment will be described. Fig. 14 shows first to fifth modifications of the first target 71 and the second target 81.

[0089] The first target 71 according to the first modification differs from the first target 71 according to the first embodiment only in that an indicator 71c indicating the position of the pinhole 71a is formed thereon. The second target 81 according to the first modification differs from the second target 81 according to the first embodiment only in that an indicator 81c indicating the target position of the position to be irradiated with a portion of the pulsed laser beam PL that has passed through the pinhole 71a is formed thereon. The indicators 71c, 81c are cross-shaped and formed by notches or grooves. The indicator 71c is an example of a "first indicator" according to the technology of the present disclosure. The indicator 81c is an example of a "second indicator" according to the technology of the present disclosure.

[0090] The first target 71 according to the second modification differs from the first target 71 according to the first embodiment only in that it has a graduated indicator 71d. The second target 81 according to the second modification differs from the second target 81 according to the first embodiment only in that it has a graduated indicator 81d. The indicators 71d and 81d are similar to the indicators 71c and 81c according to the first modification, except that they have a scale.

[0091] The second target 81 according to the third modification differs from the second target 81 according to the first embodiment only in that a pinhole 81a is formed at a target position where a portion of the pulsed laser light PL that has passed through the pinhole 71a is irradiated. In the first target 71 according to the third modification, the diameter of the pinhole 71a is larger than the diameter of the pinhole 81a of the second target 81. For example, if the diameter of the pinhole 81a is 1 mm, the diameter of the pinhole 71a is 2 mm. The portion of the pulsed laser light PL that has passed through the pinhole 71a of the first target 71 is irradiated onto a region of the second target 81 that includes the pinhole 81a. The pinhole 81a is an example of a "second passage hole" according to the technology of the present disclosure.

[0092] The first target 71 according to the fourth modification differs from the first target 71 according to the third modification only in that an indicator 71c similar to that of the first modification is further formed. The second target 81 according to the fourth modification differs from the second target 81 according to the third modification only in that an indicator 81c similar to that of the first modification is further formed.

[0093] The first target 71 according to the fifth modified example differs from the first target 71 according to the third modified example only in that it further has a graduated indicator 71d similar to that of the second modified example. The second target 81 according to the fourth modified example differs from the second target 81 according to the third modified example only in that it further has a graduated indicator 81d similar to that of the second modified example.

[0094] According to the first to fifth modifications, the irradiation positions of the pulsed laser beam PL on the first target 71 and the second target 81 can be confirmed more accurately than in the first embodiment, and therefore alignment adjustment can be performed more accurately.

[0095] The indicators 71c, 81c, 71d, and 81d are not limited to a cross shape, but may be Y-shaped, star-shaped, a shape with multiple straight lines radiating from a single point, or a shape with multiple similar polygons that share the same center.

[0096] 3. Second embodiment A laser device 2 according to a second embodiment of the present disclosure will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0097] 3.1 Configuration The laser device 2 according to this embodiment has the same configuration as the laser device 2 according to the comparative example, except for the pulse width stretching system.

[0098] 15 is a view of a pulse stretching system according to the second embodiment, viewed from diagonally above. The pulse stretching system according to this embodiment differs from the first embodiment in the position at which the second target 81 is disposed. Specifically, in this embodiment, the second target 81 is disposed so as to be retractable in the optical path between the high-reflection mirror 68 and the high-reflection mirror 42a. For example, the second target 81 is disposed in an optical path tube outside the case 69 connected to the opening 69c, and at a position close to the high-reflection mirror 42a.

[0099] In this embodiment as well, the first target 71 and the second target 81 are configured to be movable by a target moving mechanism. Separate target moving mechanisms may be provided for the first target 71 and the second target 81. As with the first embodiment and each of the modified examples, the target moving mechanism may be a tiltable type, a sliding type, a rotating type, or the like.

[0100] 3.2 Operation The operation of the laser device 2 according to this embodiment regarding the output of the pulsed laser light PL is the same as that of the comparative example. Also, the operation of the laser device 2 according to this embodiment regarding the alignment adjustment of the optical axis is the same as that of the first embodiment.

[0101] In this embodiment, the worker adjusts the first steering section 41 while observing the first target 71 visually or using the camera 100 through the window 69d, as in the first embodiment.

[0102] On the other hand, since it is difficult for an operator to visually observe the second target 81, it is preferable to adjust the first steering unit 41 while observing using the camera 120. Specifically, the camera 120 is disposed in a position facing the second target 81 across the high-reflection mirror 42a. The high-reflection mirror 42a has the property of transmitting visible light. The camera 120 captures an image of the second target 81 by receiving fluorescence emitted by the second target 81 via the high-reflection mirror 42a. The camera 120 may be disposed so as to capture an image of the second target 81 from outside the optical path tube through a window provided in the optical path tube.

[0103] 3.3 Effects In this embodiment, the distance between the first target 71 and the second target 81 is longer than in the first embodiment, so the angle of the optical axis can be adjusted with higher precision.

[0104] 4. Third embodiment A laser device 2 according to a third embodiment of the present disclosure will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0105] 4.1 Configuration The laser device 2 according to this embodiment has the same configuration as the laser device 2 according to the comparative example, except for the pulse width stretching system.

[0106] 16 is a view of a pulse stretching system according to a third embodiment, viewed from diagonally above. The pulse stretching system according to this embodiment differs from the first embodiment only in the configuration of the first target 71. In this embodiment, the first target 71 is provided with two pinholes 71a and 71b.

[0107] Each optical element constituting L-OPS 60 gradually deteriorates when irradiated with pulsed laser light PL, and therefore the optical axis may be changed to extend its service life. The optical axis in L-OPS 60 is changed by adjusting first steering unit 41. In addition, second steering unit 42 is adjusted so that the output optical path of pulsed laser light PL output from PO beam steering unit 40 does not change when the optical axis in L-OPS 60 is changed.

[0108] 16 shows the first optical axis OA1 before the change and the second optical axis OA2 after the change. The first optical axis OA1 and the second optical axis OA2 are substantially parallel within the L-OPS 60. For example, the first optical axis OA1 can be made the second optical axis OA2 by rotating the high-reflection mirror 41a around the V axis to tilt the first optical axis OA1 in the Z axis direction, and then rotating the high-reflection mirror 41b. Furthermore, by rotating the high-reflection mirror 42a, the second optical axis OA2 can be aligned with the position of the first optical axis OA1 on the high-reflection mirror 42b, and by rotating the high-reflection mirror 42b around the V axis, the second optical axis OA2 can be aligned with the output optical path.

[0109] By changing from the first optical axis OA1 to the second optical axis OA2 in this way, it is possible to change the incident position of the pulsed laser beam PL on each optical element constituting the L-OPS 60. By operating the laser device 2 using the first optical axis OA1 and changing to the second optical axis OA2 when deterioration occurs in each optical element, it is possible to extend the service life of the L-OPS 60.

[0110] The pinholes 71a and 71b of the first target 71 are provided at positions spaced apart by a distance corresponding to the distance between the first optical axis OA1 and the second optical axis OA2. The second target 81 has the same configuration as in the first embodiment.

[0111] Similar to the first embodiment, the first target 71 and the second target 81 are configured to be movable by a target movement mechanism. Similar to the first embodiment and each modified example, the target movement mechanism can be a tiltable mechanism, a sliding mechanism, a rotating mechanism, or the like. When the first target 71 is placed in the optical path by the target movement mechanism, the pinhole 71a is positioned where the first optical axis OA1 passes, and the pinhole 71b is positioned where the second optical axis OA2 passes.

[0112] 4.2 Operation The operation of the laser device 2 according to this embodiment regarding the output of the pulsed laser light PL is the same as that of the comparative example, except that the first optical axis OA1 is changed to the second optical axis OA2 in response to deterioration of the L-OPS 60. In this embodiment, alignment adjustment can be performed regardless of whether the first optical axis OA1 or the second optical axis OA2 is used.

[0113] 17, the operator adjusts the first steering unit 41 so that the center of the irradiation area coincides with the pinhole 71a, and checks the position at which the pulsed laser beam PL that has passed through the pinhole 71a is irradiated onto the second target 81. If the irradiation position does not coincide with the target position of the second target 81, the operator adjusts the first steering unit 41 so that it coincides with the target position. In this case, the target position is the position at which the design optical axis of the first optical axis OA1 passes through the second target 81.

[0114] On the other hand, when the second optical axis OA2 is used, the operator adjusts the first steering unit 41 so that the center of the irradiation area coincides with the pinhole 71b, as shown in Fig. 18, and checks the position at which the pulsed laser beam PL that has passed through the pinhole 71b is irradiated onto the second target 81. If the irradiation position does not coincide with the target position of the second target 81, the operator adjusts the first steering unit 41 so that it coincides with the target position. In this case, the target position is the position at which the design optical axis of the second optical axis OA2 passes through the second target 81.

[0115] 4.3 Effects In this embodiment, alignment adjustment can be performed with high accuracy even when the optical axis is changed to extend the service life of the L-OPS 60. Furthermore, similar to the first embodiment, alignment adjustment can be completed in a short time.

[0116] In the third embodiment, the optical axis of L-OPS 60 can be set to two positions, but it may be set to three or more positions. That is, three or more pinholes may be provided in first target 71 to correspond to the three or more positions where the optical axis is set.

[0117] 4.4 Target Variations Next, various modified examples of the first target 71 and the second target 81 according to the third embodiment will be described. Fig. 19 and Fig. 20 show first to fifth modified examples of the first target 71 and the second target 81. Fig. 19 shows the irradiation area when the first optical axis OA1 is used. Fig. 20 shows the irradiation area when the second optical axis OA2 is used.

[0118] The first target 71 according to the first modification is different from the first target 71 according to the third embodiment only in that it is provided with indicators 71c that indicate the positions of the pinholes 71a and 71b. The second target 81 according to the first modification is different from the second target 81 according to the third embodiment only in that it is provided with indicators 81c that indicate the target positions to be irradiated with portions of the pulsed laser beam PL that has passed through the pinholes 71a and 71b. The indicators 71c and 81c are formed by notches or grooves.

[0119] The first target 71 according to the second modification is different from the first target 71 according to the third embodiment only in that it is provided with a graduated indicator 71d that indicates the positions of each of the pinholes 71a and 71b. The second target 81 according to the second modification is different from the second target 81 according to the third embodiment only in that it is provided with a graduated indicator 81d that indicates each target position to be irradiated with a portion of the pulsed laser beam PL that has passed through the pinholes 71a and 71b. The indicators 71d and 81d are similar to the indicators 71c and 81c according to the first modification, except that they have graduated indicators.

[0120] The second target 81 according to the third modification differs from the second target 81 according to the third embodiment only in that a pinhole 81a is formed at a target position where a portion of the pulsed laser beam PL that has passed through the pinhole 71a is irradiated, and a pinhole 81b is formed at a target position where a portion of the pulsed laser beam PL that has passed through the pinhole 71b is irradiated. In the first target 71 according to the third modification, the diameters of the pinholes 71a and 71b are larger than the diameters of the pinholes 81a and 81b of the second target 81. For example, if the diameters of the pinholes 81a and 81b are 1 mm, the diameters of the pinholes 71a and 71b are 2 mm. The portion of the pulsed laser beam PL that has passed through the pinhole 71a of the first target 71 is irradiated onto a region of the second target 81 that includes the pinhole 81a. The portion of the pulsed laser beam PL that has passed through the pinhole 71b of the first target 71 is irradiated onto a region of the second target 81 that includes the pinhole 81b.

[0121] The first target 71 according to the fourth modification differs from the first target 71 according to the third modification only in that an indicator 71c similar to that of the first modification is further formed. The second target 81 according to the fourth modification differs from the second target 81 according to the third modification only in that an indicator 81c similar to that of the first modification is further formed.

[0122] The first target 71 according to the fifth modified example differs from the first target 71 according to the third modified example only in that a graduated indicator 71d similar to that of the second modified example is further formed. The second target 81 according to the fifth modified example differs from the second target 81 according to the third modified example only in that a graduated indicator 81d similar to that of the second modified example is further formed.

[0123] According to the first to fifth modifications, the irradiation positions of the pulsed laser beam PL on the first target 71 and the second target 81 can be confirmed more accurately than in the third embodiment, and therefore alignment adjustment can be performed more accurately.

[0124] The indicators 71c, 81c, 71d, and 81d are not limited to a cross shape, but may be Y-shaped, star-shaped, a shape with multiple straight lines radiating from a single point, or a shape with multiple similar polygons that share the same center.

[0125] 5. Modifications of the First to Third Embodiments Next, various modified examples common to the first to third embodiments will be described. In each of the above embodiments, the first target 71 and the second target 81 are each circular, but they are not limited to being circular and may be other shapes such as triangular or rectangular. Furthermore, the first target 71 and the second target 81 are not limited to being targets that emit fluorescence when irradiated with pulsed laser light PL, as long as the areas irradiated with the pulsed laser light PL can be identified.

[0126] In addition, in each of the above embodiments, two targets are arranged so as to be retractable in the optical path including the L-OPS 60, but only one target may be arranged so as to be retractable. In this case, the target does not need to have a pinhole. Even when only one target is used, the position of the optical axis can be adjusted as an alignment adjustment.

[0127] 6. Manufacturing method of electronic devices 21 shows a schematic configuration example of an exposure apparatus 200. The exposure apparatus 200 includes an illumination optical system 204 and a projection optical system 206. The illumination optical system 204 illuminates a reticle pattern of a reticle (not shown) placed on a reticle stage RT with pulsed laser light PL incident from, for example, a laser device 2. The projection optical system 206 reduces and projects the pulsed laser light PL 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.

[0128] The exposure apparatus 200 exposes the workpiece with pulsed laser light PL reflecting the reticle pattern by synchronously translating the reticle stage RT and the workpiece table WT. After the reticle pattern is transferred to the 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.

[0129] The above description is intended to be illustrative rather than limiting. Thus, it will be apparent to those skilled in the art that modifications may be made to the embodiments of the present disclosure without departing from the scope of the appended claims.

[0130] Terms used throughout this specification and the appended claims should be interpreted as "open-ended" terms. For example, the terms "including" or "including" should be interpreted as "not limited to what is stated as including." The term "having" should be interpreted as "not limited to what is stated as having." Additionally, the modifier "a" or "an" used in this specification and the appended claims should be interpreted as meaning "at least one" or "one or more."

[0131] The above description is intended to be illustrative, not limiting. Accordingly, it will be apparent to those skilled in the art that modifications can be made to the embodiments of the present disclosure without departing from the scope of the claims. It will also be apparent to those skilled in the art that the embodiments of the present disclosure can be used in combination. Terms used throughout this specification and claims should be construed as "open-ended" terms unless expressly stated. For example, terms such as "comprise," "have," "comprise," and "equip" should be interpreted as meaning "without excluding the presence of elements other than those listed." The modifier "a" or "an" should be interpreted as meaning "at least one" or "one or more." The term "at least one of A, B, and C" should be interpreted as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C," including combinations other than "A," "B," and "C."

Claims

1. A pulse width stretching system that stretches the pulse width of an incident pulsed laser beam and outputs the stretched pulsed laser beam, a pulse width stretching optical system including a beam splitter and a plurality of mirrors; a case that houses the pulse width stretching optical system; at least one target configured so that a portion irradiated with the pulsed laser light can be distinguished; a target moving mechanism that enables the at least one target to be placed in an optical path of the pulsed laser beam including the pulse width stretching optical system and the at least one target to be retracted from the optical path; A pulse width stretching system comprising:

2. 2. The pulse stretching system of claim 1, The plurality of mirrors form a loop optical path that circulates a portion of the pulsed laser light reflected by the beam splitter and returns it to the beam splitter.

3. 2. The pulse stretching system of claim 1, The optical system includes a steering device including a plurality of steering mirrors for adjusting the alignment of the optical axis of the pulsed laser light incident on the pulse width expanding optical system.

4. 2. The pulse stretching system of claim 1, The at least one target emits fluorescence at a portion irradiated with the pulsed laser light.

5. 2. The pulse stretching system of claim 1, The target moving mechanism is capable of moving the at least one target between a collapsed state and an upright state.

6. 2. The pulse stretching system of claim 1, The target moving mechanism allows the at least one target to slide.

7. 2. The pulse stretching system of claim 1, The target moving mechanism is capable of rotating the at least one target.

8. 2. The pulse stretching system of claim 1, the at least one target is housed in the case; The case has a window formed therein that allows the at least one target to be observed from outside the case.

9. 9. A pulse stretching system according to claim 8, comprising: A camera is provided that captures an image of the at least one target from outside the case through the window.

10. 2. The pulse stretching system of claim 1, the at least one target includes a first target and a second target; the first target and the second target are configured to be movable by the target moving mechanism, The first target is disposed upstream of the second target in the optical path.

11. 11. A pulse stretching system according to claim 10, comprising: The first target has at least one first through hole formed therein through which a portion of the pulsed laser beam passes.

12. 12. A pulse stretching system according to claim 11, comprising: The first target has a first indicator formed thereon that indicates the position of the at least one first through hole.

13. 13. A pulse stretching system according to claim 12, comprising: The second target is formed with a second indicator that indicates a target position where a portion of the pulsed laser beam that has passed through the at least one first passage hole is irradiated.

14. 12. A pulse stretching system according to claim 11, comprising: the second target has the at least one second passage hole formed therein; The diameter of the at least one first through hole is larger than the diameter of the at least one second through hole.

15. 13. A pulse stretching system according to claim 12, comprising: The second target has a second indicator formed thereon that indicates the position of the at least one second through hole.

16. A laser device comprising: a laser oscillator that outputs pulsed laser light; and a pulse width stretching system that stretches the pulse width of the incident pulsed laser light and outputs the stretched pulsed laser light, the pulse stretching system a pulse width stretching optical system including a beam splitter and a plurality of mirrors; a case that houses the pulse width stretching optical system; at least one target configured so that a portion irradiated with the pulsed laser light can be distinguished; a target moving mechanism that can place the at least one target in an optical path including the pulse width stretching optical system and move the at least one target out of the optical path; A laser device comprising:

17. A method for manufacturing an electronic device, comprising: A laser device comprising: a laser oscillator that outputs pulsed laser light; and a pulse width stretching system that stretches the pulse width of the incident pulsed laser light and outputs the stretched pulsed laser light, the pulse stretching system a pulse width stretching optical system including a beam splitter and a plurality of mirrors; a case that houses the pulse width stretching optical system; at least one target configured so that a portion irradiated with the pulsed laser light can be distinguished; a target moving mechanism that can place the at least one target in an optical path including the pulse width stretching optical system and move the at least one target out of the optical path; generating the pulsed laser light having the extended pulse width by a laser device including: outputting the pulsed laser light to an exposure device; exposing a photosensitive substrate to the pulsed laser light in the exposure apparatus to manufacture an electronic device; A method for manufacturing electronic devices.

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