Gas laser device and method for manufacturing electronic device

Abstract

A gas laser device includes a cavity device that emits light generated from a laser gas, a resonator that resonates the light emitted from the cavity device between both sides across the cavity device, and a beam expander, the resonator including an output coupling mirror that is disposed on one side across the cavity device and that transmits a portion of the light emitted from the cavity device, the output coupling mirror being disposed on the other side across the cavity device. And an output coupling mirror that reflects another part of the light emitted from the cavity device so as to return to the cavity device, the beam expander being disposed between the cavity device and the output coupling mirror, the beam expander including: a holding portion; a convex mirror that includes a reflecting surface that reflects light emitted from the cavity device so as to enlarge the beam width of the light, and a plurality of side surfaces that are fixed to the holding part by an adhesive on only one side surface; and a concave mirror including a reflecting surface and a plurality of side surfaces, the reflecting surface reflecting the light reflected by the convex mirror toward the output coupling mirror in a collimation manner, the collimation fixing the expanded beam width of the light, and only one side surface being fixed to the holding part by an adhesive.

Description

Technical Field

[0001] This disclosure relates to methods for manufacturing gas laser devices and electronic components. Background Technology

[0002] In recent years, with the miniaturization and high integration of semiconductor integrated circuits, there has been a demand for higher resolution in semiconductor exposure equipment. Therefore, the use of shorter wavelengths of light emitted from exposure light sources has been developed. For example, as gas laser devices for exposure, KrF excimer lasers using lasers with an output wavelength of approximately 248.0 nm and ArF excimer lasers using lasers with an output wavelength of approximately 193.4 nm are examples.

[0003] The natural oscillating light from KrF and ArF excimer lasers has a wide spectral linewidth, ranging from 350 pm to 400 pm. Therefore, when using projection lenses made of materials that allow ultraviolet light to pass through KrF and ArF lasers, chromatic aberration sometimes occurs. As a result, resolution may be reduced. Therefore, it is necessary to narrow the spectral linewidth of the laser output from the gas laser device to a level that eliminates chromatic aberration. Thus, in the laser resonator of a gas laser device, a line-narrowing module (LNM) containing narrowing elements (etalon, grating, etc.) is sometimes included to achieve this narrowing. Hereinafter, gas laser devices with narrowed spectral linewidths will be referred to as narrow-bandgap gas laser devices.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-018076

[0007] Patent Document 2: U.S. Patent Application Publication No. 2021 / 0336407 Summary of the Invention

[0008] One aspect of the gas laser device disclosed herein may also include: a cavity device containing a pair of opposing discharge electrodes within an internal space enclosed in a laser gas, emitting light generated from the laser gas by applying a voltage between the pair of discharge electrodes; a resonator that causes the light emitted from the cavity device to resonate between two sides of the cavity device; and a beam expander, the resonator including an output coupling mirror disposed on one side of the cavity device, allowing a portion of the light emitted from the cavity device to pass through and reflecting another portion of the light emitted from the cavity device back into the cavity device, thus expanding the beam. The beam expander is disposed between a cavity device and an output coupling mirror. The beam expander includes: a holding portion; a convex mirror having a reflective surface and a plurality of side surfaces, the reflective surface reflecting light in a manner that expands the beam width of light emitted from the cavity device, only one of the plurality of side surfaces being fixed to the holding portion by an adhesive; and a concave mirror having a reflective surface and a plurality of side surfaces, the reflective surface reflecting light reflected by the convex mirror toward the output coupling mirror in a manner that collimates the light, thereby fixing the expanded beam width of the light, only one of the plurality of side surfaces being fixed to the holding portion by an adhesive.

[0009] One method for manufacturing an electronic device according to this disclosure may also include the following steps: generating a pulsed laser using a gas laser device, outputting the pulsed laser to an exposure device, and exposing the pulsed laser on a photosensitive substrate within the exposure device to manufacture the electronic device. The gas laser device comprises: a cavity device containing a pair of opposing discharge electrodes within an internal space enclosed in laser gas, emitting light generated from the laser gas by applying a voltage between the pair of discharge electrodes; a resonator that causes the light emitted from the cavity device to resonate between two sides of the cavity device; and a beam expander, the resonator including an output coupling mirror disposed on one side of the cavity device to cause the light emitted from the cavity device to resonate between two sides of the cavity device. A portion of the light emitted from the cavity device is transmitted, while another portion is reflected back into the cavity device. A beam expander is disposed between the cavity device and the output coupling mirror. The beam expander includes: a holding portion; a convex mirror having a reflective surface and a plurality of side surfaces, the reflective surface reflecting the light in a manner that expands the beam width of the light emitted from the cavity device, only one of the plurality of side surfaces being fixed to the holding portion by an adhesive; and a concave mirror having a reflective surface and a plurality of side surfaces, the reflective surface reflecting the light reflected by the convex mirror toward the output coupling mirror in a manner that collimates the light, thereby fixing the expanded beam width of the light, only one of the plurality of side surfaces being fixed to the holding portion by an adhesive. Attached Figure Description

[0010] Hereinafter, several embodiments of the present disclosure will be described by way of example only, with reference to the accompanying drawings.

[0011] Figure 1This is a schematic diagram illustrating a general structural example of an electronic device manufacturing apparatus.

[0012] Figure 2 This is a schematic diagram showing the overall general structure of a comparative example gas laser device.

[0013] Figure 3 This is a schematic diagram showing a schematic example of the beam expander structure of a comparative example.

[0014] Figure 4 This is a perspective view showing a convex mirror and a concave mirror as comparative examples.

[0015] Figure 5 This is a cross-sectional view of a convex mirror.

[0016] Figure 6 This is a cross-sectional view of a concave mirror.

[0017] Figure 7 This diagram shows the convex mirror being fixed to the convex mirror holder using adhesive.

[0018] Figure 8 This diagram shows the concave mirror being fixed to a concave mirror holder using an adhesive.

[0019] Figure 9 Is with Figure 3 Similarly, a schematic diagram of a general structural example of the beam expander of Embodiment 1 is shown.

[0020] Figure 10 It is along Figure 9 The cross-sectional view of the beam expander for the XX line shown.

[0021] Figure 11 It is along Figure 9 A cross-sectional view of the beam expander for the XI-XI line shown.

[0022] Figure 12 Is with Figure 3 Similarly, a schematic diagram of a general structural example of the beam expander of Embodiment 2 is shown.

[0023] Figure 13 Is with Figure 4 Similarly, perspective views of the convex mirror, plane mirror, and concave mirror of Embodiment 2 are shown.

[0024] Figure 14 It is along Figure 12 A cross-sectional view of the beam expander for the XIV-XIV line shown.

[0025] Figure 15 Is with Figure 3 Similarly, a schematic diagram of a general structural example of the beam expander of Embodiment 3 is shown.

[0026] Figure 16 Is with Figure 4 Similarly, perspective views of the convex mirror, the first plane mirror, the second plane mirror, and the concave mirror of Embodiment 3 are shown.

[0027] Figure 17 It is along Figure 15 A cross-sectional view of the beam expander of the XVII-XVII line shown. Detailed Implementation

[0028] 1. Description of the electronic device manufacturing apparatus used in the exposure process of electronic devices

[0029] 2. Description of the comparative gas laser device

[0030] 2.1 Structure

[0031] 2.2 Actions

[0032] 2.3 Research Topic

[0033] 3. Description of the gas laser device in Embodiment 1

[0034] 3.1 Structure

[0035] 3.2 Actions

[0036] 3.3 Functions / Effects

[0037] 4. Description of the gas laser device in Embodiment 2

[0038] 4.1 Structure

[0039] 4.2 Actions

[0040] 4.3 Functions / Effects

[0041] 5. Description of the gas laser device in Embodiment 3

[0042] 5.1 Structure

[0043] 5.2 Actions

[0044] 5.3 Functions / Effects

[0045] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. The embodiments described below illustrate several examples of this disclosure and do not limit its scope. Furthermore, the structures and operations described in each embodiment are not necessarily all necessary for the structures and operations of this disclosure. Additionally, the same reference numerals are used to denote the same structural elements, and repeated descriptions are omitted.

[0046] 1. Description of the electronic device manufacturing apparatus used in the exposure process of electronic devices

[0047] Figure 1 This is a schematic diagram illustrating a general structural example of an electronic device manufacturing apparatus used in the exposure process of an electronic device. For example... Figure 1 As shown, the manufacturing apparatus used in the exposure process includes a gas laser device 100 and an exposure device 200. The exposure device 200 includes an illumination optics system 210 and a projection optics system 220. The illumination optics system 210 includes multiple mirrors 211, 212, and 213. The illumination optics system 210 illuminates the mask pattern on the mask stage RT using laser light incident from the gas laser device 100. The projection optics system 220 projects the laser light after it has passed through the mask onto a workpiece (not shown) disposed on a workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist. The exposure device 200 moves the mask stage RT and the workpiece stage WT synchronously and parallel, thereby exposing the workpiece with laser light reflecting the mask pattern. Through this exposure process, a device pattern is transferred onto a semiconductor wafer, thereby enabling the manufacture of semiconductor devices as electronic devices.

[0048] 2. Description of the comparative gas laser device

[0049] 2.1 Structure

[0050] The gas laser apparatus of the comparative example will be described. Furthermore, the comparative examples disclosed herein are methods known only to the applicant and are not publicly known examples acknowledged by the applicant.

[0051] Figure 2 This is a schematic diagram illustrating the overall general structure of the gas laser device 100 in this example. The gas laser device 100 is, for example, an ArF excimer laser device using a mixture of argon (Ar), fluorine (F2), and neon (Ne). This gas laser device 100 outputs laser light with a center wavelength of approximately 193.4 nm. Alternatively, the gas laser device 100 can also be a gas laser device other than an ArF excimer laser device, for example, a KrF excimer laser device using a mixture of krypton (Kr), F2, and Ne. In this case, the gas laser device 100 emits laser light with a center wavelength of approximately 248.0 nm. The mixture of Ar, F2, and Ne as the laser medium, and the mixture of Kr, F2, and Ne as the laser medium, are sometimes referred to as laser gases. Furthermore, in the mixtures used in the ArF excimer laser device and the KrF excimer laser device, helium (He) can be used instead of Ne.

[0052] The gas laser device 100 in this example includes a housing 110, and a laser oscillator 130 as the main oscillator, an optical transmission unit 141, an amplifier 160 as the power oscillator, a detection unit 153, a display unit 180, a processor 190, a laser gas exhaust device 701, and a laser gas supply device 703 disposed in the internal space of the housing 110 as the main structure.

[0053] The laser oscillator 130 includes a cavity device CH1, a charger 41, a pulse power module 43, a narrowband module 60, and an output coupling mirror 70 as its main structures.

[0054] exist Figure 2 The image shows the internal structure of the cavity device CH1 as viewed from a direction approximately perpendicular to the direction of laser travel. The cavity device CH1 has a housing 30, a pair of windows 31a and 31b, a pair of electrodes 32a and 32b, an insulating part 33, a feed passage part 34, and an electrode holder part 36 as its main structures.

[0055] Regarding the housing 30, the aforementioned laser gas is supplied from the laser gas supply device 703 to the internal space of the housing 30 via piping, thereby sealing the internal space with laser gas. The internal space is the space in which light is generated by the excitation of the laser medium in the laser gas. This light travels toward windows 31a and 31b.

[0056] Window 31a is disposed on the front wall of housing 30 in the direction of laser travel from gas laser device 100 to exposure device 200, and window 31b is disposed on the rear wall of housing 30 in the same direction of travel. Windows 31a and 31b are calcium fluoride substrates, and the inner and outer surfaces of housing 30 in windows 31a and 31b are planar. Furthermore, windows 31a and 31b need only be able to allow laser transmission, and are not limited to calcium fluoride substrates. Windows 31a and 31b are tilted at a Brewster angle relative to the direction of laser travel to suppress reflection of P-polarized light from the laser.

[0057] Electrodes 32a and 32b are arranged opposite each other within the interior space of housing 30, with their length direction aligned with the direction of light propagation, which is generated by a high voltage applied between electrodes 32a and 32b. The space between electrodes 32a and 32b within housing 30 is located between windows 31a and 31b. Electrodes 32a and 32b are discharge electrodes used to excite the laser medium via glow discharge. In this example, electrode 32a is the cathode, and electrode 32b is the anode.

[0058] Electrode 32a is supported by insulating portion 33. Insulating portion 33 blocks the opening formed in housing 30. Insulating portion 33 includes an insulator. Furthermore, a feedthrough portion 34 composed of conductive components is disposed in insulating portion 33. Feedthrough portion 34 applies the voltage supplied from pulse power module 43 to electrode 32a. Electrode 32b is supported by electrode holder portion 36 and is electrically connected to electrode holder portion 36.

[0059] Charger 41 is a DC power supply device that charges a capacitor (not shown) disposed inside pulse power module 43 with a specified voltage. Charger 41 is disposed outside housing 30 and connected to pulse power module 43. Pulse power module 43 includes a switch (not shown) controlled by processor 190. Pulse power module 43 is a voltage application circuit that boosts the voltage applied from charger 41 to generate a pulsed high voltage when the switch is switched from open to closed by the control, and applies the high voltage to electrodes 32a and 32b. When the high voltage is applied, a discharge occurs between electrodes 32a and 32b. The energy from this discharge excites the laser medium inside housing 30. When the excited laser gas transitions to the ground state, it emits light, which exits through windows 31a and 31b to the outside of housing 30.

[0060] The narrowband module 60 includes a housing 65, and a prism 61, a grating 63, and a rotary table (not shown) disposed within the interior space of the housing 65. An opening is formed in the housing 65, and the housing 65 is connected to the rear side of the housing 30 via the opening.

[0061] Prism 61 widens the beam width of light emitted from window 31b, allowing this light to enter the grating 63. Furthermore, prism 61 narrows the beam width of reflected light from the grating 63, causing this light to return via window 31b to the interior space of housing 30. Prism 61 is supported by a rotary table and rotates via the table. The rotation of prism 61 changes the angle of incidence of light relative to the grating 63. Therefore, by rotating prism 61, the wavelength of light returning from the grating 63 to housing 30 via prism 61 can be selected. Figure 2 The example shown is configured with one prism 61, but more than two prisms can also be configured.

[0062] The surface of the grating 63 is made of a highly reflective material, and multiple grooves are arranged on the surface at predetermined intervals. The grating 63 is a dispersive optical element. The cross-sectional shape of each groove is, for example, a right-angled triangle. Light incident from the prism 61 onto the grating 63 is reflected by these grooves and diffracted in a direction corresponding to the wavelength of the light. The grating 63 is configured in a Littlero configuration so that the angle of incidence of the light incident from the prism 61 onto the grating 63 coincides with the diffraction angle of the diffracted light of the desired wavelength. Thus, light of the desired wavelength returns to the housing 30 via the prism 61.

[0063] The output coupling mirror 70 faces the window 31a, allowing a portion of the laser emitted from the window 31a to pass through, while the remaining portion is reflected and returns through the window 31a to the interior space of the housing 30. The output coupling mirror 70 is fixed to a holder (not shown) and is disposed within the interior space of the housing 110.

[0064] A Fabry-Perot type resonator is constructed using a grating 63 and an output coupling mirror 70 disposed between the housing 30 and the resonator. The housing 30 is positioned in the optical path of the resonator. Therefore, the resonator causes optical resonance between the two sides of the cavity-separated device CH1.

[0065] The optical transmission unit 141 includes highly reflective mirrors 141b and 141c as its main structure. The highly reflective mirrors 141b and 141c are fixed to holders (not shown) at their respective tilt angles and are disposed within the interior space of the housing 110. The highly reflective mirrors 141b and 141c cause high reflection of the laser light. The highly reflective mirrors 141b and 141c are positioned in the optical path of the laser light from the output coupling mirror 70. The laser light is reflected by the highly reflective mirrors 141b and 141c and travels towards the rear mirror 371 of the amplifier 160. At least a portion of the laser light passes through the rear mirror 371.

[0066] Amplifier 160 amplifies the energy of the laser output from laser oscillator 130. The basic structure of amplifier 160 is largely the same as that of laser oscillator 130. To distinguish the structural elements of amplifier 160 from those of laser oscillator 130, it will be described as a cavity device CH3, housing 330, a pair of windows 331a and 331b, a pair of electrodes 332a and 332b, insulation 333, feedthrough 334, electrode holder 336, charger 341, pulse power module 343, and output coupling mirror 370. Electrodes 332a and 332b generate discharges for amplifying the laser from laser oscillator 130. Similar to pulse power module 43, pulse power module 343 is a voltage application circuit.

[0067] Furthermore, the main difference between amplifier 160 and laser oscillator 130 is that amplifier 160 does not have narrowband module 60, but has rear mirror 371 and beam expander 400.

[0068] The rear mirror 371 is positioned between the high-reflectivity mirror 141c and the window 331b, facing them respectively. The rear mirror 371 allows a portion of the laser light from the laser oscillator 130 to pass through into the space between the electrodes 332a and 332b, and allows a portion of the laser light amplified by the electrodes 332a and 332b to be reflected into the space between the electrodes 332a and 332b.

[0069] The output coupling mirror 370 is positioned on the side of the cavity device CH3 opposite to the rear mirror 371, and the beam expander 400 is positioned between the cavity device CH3 and the output coupling mirror 370.

[0070] Figure 3 This is a schematic diagram showing a general structural example of the beam expander 400 in this example. It is a schematic diagram of the beam expander 400 viewed along a direction perpendicular to the direction in which the optical axis LA1 of the laser emitted from window 331a and the electrodes 332a and 332b are opposite each other. Figure 3 As shown, in this example, the beam expander 400 includes a convex mirror 410, a concave mirror 420, and a retaining part 450.

[0071] Figure 4 This is a perspective view showing the convex mirror 410 and the concave mirror 420 in this example. The convex mirror 410 is a plate-like component including a reflective surface 411 for reflecting light, multiple side surfaces 412, and a back surface 413 located inside the reflective surface 411 and opposite it. The concave mirror 420 is a plate-like component including a reflective surface 421 for reflecting light, multiple side surfaces 422, and a back surface 423 located inside the reflective surface 421 and opposite it. The reflective surface 411 of the convex mirror 410 reflects the laser beam from the cavity device CH3 toward the concave mirror 420 in a manner that expands the beam width. The reflective surface 421 of the concave mirror 420 collimates the laser beam reflected from the convex mirror 410 toward the output coupling mirror 370, thereby fixing the expanded beam width of the laser beam. Furthermore, the concave mirror 420 reflects the laser beam from the output coupling mirror 370 toward the convex mirror 410 in a manner that reduces the beam width. The convex mirror 410 collimates the laser beam reflected from the concave mirror 420 toward the cavity device CH3, thereby fixing the reduced beam width of the laser beam, which then returns to the interior space of the housing 330 via the window 331a.

[0072] In this example, the convex mirror 410 is a convex cylindrical mirror. When the reflecting surface 411 is viewed from the front, the shape of the convex mirror 410 is a rectangle that is longer in the direction parallel to the focal line 410L of the convex mirror 410. Similarly, the concave mirror 420 is a concave cylindrical mirror. When the reflecting surface 421 is viewed from the front, the shape of the concave mirror 420 is a rectangle that is longer in the direction parallel to the focal line 420L of the concave mirror 420. Therefore, the convex mirror 410 includes four planar side surfaces 412, and the concave mirror 420 includes four planar side surfaces 422. Furthermore, the focal line 410L is the line connecting the focal point of the convex mirror 410, and the focal line 420L is the line connecting the focal point of the concave mirror 420. Moreover, the shapes of the convex mirror 410 and the concave mirror 420, as well as the number of side surfaces 412 and 422, are not limited. For example, the shape of the convex mirror 410 can also be a longer rectangle in the direction perpendicular to the focal line 410L, and the shape of the concave mirror 420 can also be a longer rectangle in the direction perpendicular to the focal line 420L.

[0073] Figure 5 This is a cross-sectional view of the convex mirror 410, the cross-section of which is parallel to the normal of the reflecting surface 411 of the convex mirror 410 and orthogonal to the incident surface of the laser emitted from the window 331a relative to the reflecting surface 411. Figure 5 As shown, the shape of the reflecting surface 411 in this cross section is an arc, but this shape is not limited, for example it can also be a parabola.

[0074] Figure 6 This is a cross-sectional view of the concave mirror 420, the cross-section of which is parallel to the normal of the reflecting surface 421 of the concave mirror 420 and orthogonal to the incident surface of the laser beam reflected from the convex mirror 410 toward the concave mirror 420 relative to the reflecting surface 421. Figure 6 As shown, the shape of the reflecting surface 421 in this cross section is an arc, but this shape is not limited, for example it can also be a parabola.

[0075] return Figure 3 The focal line 410L of the convex mirror 410 is contained in a plane extending in the direction in which the laser-containing optical axis LA1 is located and in the direction in which the electrodes 332a and 332b are opposite each other, and is tilted in a manner that moves away from the cavity device CH3 and closer to the electrode 332a side. Similarly, the focal line 420L of the concave mirror 420 is contained in the plane containing the laser optical axis LA1 and the focal line 410L, and is tilted in a manner that moves away from the cavity device CH3 and closer to the electrode 332a side. Furthermore, the focal lines 410L and 420L are located on the same straight line. That is, the positions of the convex mirror 410 and the concave mirror 420 are adjusted in this way. Alternatively, the focal lines 410L and 420L may not be located on the same straight line.

[0076] The retaining part 450 holds the convex mirror 410 and the concave mirror 420. In this example, the retaining part 450 includes a base member 451, a convex mirror holder 460, and a concave mirror holder 470.

[0077] In this example, the convex mirror retainer 460 is a plate-shaped component extending along the back surface 413 of the convex mirror 410, and the back surface 413 of the convex mirror 410 is fixed to the main surface 461 on the side near the convex mirror 410 using an adhesive. Figure 7 This diagram shows the convex mirror 410 being fixed to the convex mirror holder 460 using adhesive. Figure 7 As shown, adhesive 462 is separated into multiple adhesive portions. Adhesive 462 is disposed between the main surface 461 of the convex mirror holder 460 and the back surface 413 of the convex mirror 410, thereby separating the main surface 461 and the back surface 413 and forming a space between the main surface 461 and the back surface 413 where no adhesive 462 is disposed. Examples of adhesive 462 include, for example, UV-curable adhesives, and examples of UV-curable adhesives include, for example, polyurethane acrylate adhesives. Alternatively, adhesive 462 may not be separated into multiple adhesive portions.

[0078] In this example, the concave mirror holder 470 is a plate-shaped component extending along the back surface 423 of the concave mirror 420, and the back surface 423 of the concave mirror 420 is fixed to the main surface 471 on the side near the concave mirror 420 using an adhesive. Figure 8 This diagram shows the concave mirror 420 being fixed to the concave mirror holder 470 using an adhesive. (See diagram below.) Figure 8 As shown, similar to adhesive 462, adhesive 472, which fixes the back surface 423 to the main surface 471, is separated into multiple adhesive portions. Therefore, adhesive 472 is disposed between the main surface 471 and the back surface 423, thereby separating the main surface 471 and the back surface 423 and forming a space between the main surface 471 and the back surface 423 where no adhesive 472 is disposed. For example, the same adhesive as adhesive 462 can be used as adhesive 472. Alternatively, adhesive 472 may not be separated into multiple adhesive portions.

[0079] In this example, the base component 451 is a plate-shaped component extending in a direction parallel to the optical axis LA1 of the laser emitted from the window 331a of the cavity device CH3. In this example, the base component 451 extends in a direction where electrodes 332a and 332b face each other. A convex mirror holder 460 and a concave mirror holder 470 are fixed to one main surface 452 of the base component 451. Thus, the convex mirror 410 is fixed to the base component 451 by means of the convex mirror holder 460, and the concave mirror 420 is fixed to the base component 451 by means of the concave mirror holder 470. Therefore, the convex mirror 410 is fixed to the holding portion 450 by adhesive 462, and the concave mirror 420 is fixed to the holding portion 450 by adhesive 472, and both the convex mirror 410 and the concave mirror 420 are held by the holding portion 450.

[0080] return Figure 2 The output coupling mirror 370 has a partially reflective film with a specified reflectivity coated on the side of the beam expander 400. Furthermore, the output coupling mirror 370 causes a portion of the laser from the cavity device CH3 after the beam width has been expanded by the beam expander 400 to be reflected toward the beam expander 400, while allowing another portion of the laser to pass through.

[0081] The output coupling mirror 370 can also be circular. The side of the output coupling mirror 370 closest to the beam expander 400 and the side opposite to it can also be planar. The rear mirror 371 and the output coupling mirror 370 have a similar structure to the output coupling mirror 70.

[0082] A resonator is constructed using a rear mirror 371 and an output coupling mirror 370, separated by a housing 330, to resonate the laser beam amplified by electrodes 332a and 332b. The housing 330 and a beam expander 400 are positioned in the optical path of the resonator. Laser light exiting from window 331a of the housing 330 is incident on the output coupling mirror 370 via the beam expander 400 and reflected by the output coupling mirror 370. The laser light, after reflection at the output coupling mirror 370, returns to the interior space of the housing 330 via the beam expander 400 and window 331b, exiting from window 331a. The laser light exiting from window 331a is reflected by the rear mirror 371 and returns to the interior space of the housing 330 via window 331b. Thus, the laser light exiting the housing 330 travels back and forth between the rear mirror 371 and the output coupling mirror 370. The traveling laser light is amplified each time it passes through the laser gain space between electrodes 332a and 332b. That is, the resonator causes the light to resonate between the two sides of the cavity-separated device CH3, and the output coupling mirror 370 is disposed on one side of the cavity-separated device CH3. A portion of the amplified laser light passes through the output coupling mirror 370. The laser light passing through the output coupling mirror 370 travels towards the detection unit 153.

[0083] The detection unit 153 includes a beam splitter 153b and a light sensor 153c as its main structures.

[0084] Beam splitter 153b is configured in the optical path of the laser passing through output coupling mirror 370. Beam splitter 153b allows the laser passing through output coupling mirror 370 to pass through exit window 173 with high transmittance, and causes a portion of the laser to be reflected toward the light-receiving surface of photosensor 153c.

[0085] Optical sensor 153c measures the pulse energy of laser light incident on its light-receiving surface. Optical sensor 153c is electrically connected to processor 190 and outputs a signal representing the measured pulse energy to processor 190. Processor 190 controls the voltage applied to electrodes 332a and 332b of amplifier 160 based on this signal.

[0086] An exit window 173 is provided on the side opposite to the output coupling mirror 370, with the beam splitter 153b of the detection unit 153 as a reference. The exit window 173 is provided on the wall of the housing 110. Light transmitted through the beam splitter 153b is emitted from the exit window 173 to the exposure device 200 outside the housing 110. This laser is, for example, a pulsed laser with a center wavelength of 193.4 nm.

[0087] The display unit 180 is a monitor that displays the status of the control performed by the processor 190 based on signals from the processor 190. The display unit 180 may also be disposed outside the housing 110.

[0088] The processor 190 of this disclosure is a processing device including a storage device storing a control program and a CPU (Central Processing Unit) that executes the control program. The processor 190 is specifically configured or programmed to perform the various processes included in this disclosure. Furthermore, the processor 190 controls the gas laser device 100 as a whole. Additionally, the processor 190 is electrically connected to an exposure processor (not shown) of the exposure device 200, and transmits and receives various signals with and from the exposure processor.

[0089] Laser gas exhaust device 701 and laser gas supply device 703 are electrically connected to processor 190. Laser gas exhaust device 701 includes an exhaust pump (not shown), which, according to a control signal from processor 190, exhausts laser gas from the internal spaces of housings 30 and 330 via piping. Laser gas supply device 703, according to a control signal from processor 190, supplies laser gas via piping to the internal spaces of housings 30 and 330; this laser gas originates from a laser gas supply source (not shown) located outside housing 110.

[0090] 2.2 Actions

[0091] Next, the operation of the comparative example gas laser device 100 will be explained.

[0092] Before the gas laser device 100 emits a laser, laser gas is supplied from the laser gas supply device 703 to the internal space of the housings 30 and 330.

[0093] When the gas laser device 100 emits laser light, the processor 190 receives a signal representing the target energy Et and a light emission trigger signal from the exposure processor (not shown) of the exposure device 200. The target energy Et is the target value of the laser energy used in the exposure process. The processor 190 sets a predetermined charging voltage to the charger 41 so that the energy E becomes the target energy Et, and synchronously switches on the pulse power module 43 with the light emission trigger signal. As a result, the pulse power module 43 uses the electrical energy held by the charger 41 to generate a pulsed high voltage, which is applied between the electrodes 32a and 32b. When the high voltage is applied, a discharge occurs between the electrodes 32a and 32b, and the laser medium contained in the laser gas between the electrodes 32a and 32b becomes excited and emits light when the laser medium returns to the ground state. The emitted light resonates between the grating 63 and the output coupling mirror 70, and is amplified each time it passes through the discharge space in the internal space of the housing 30, generating laser oscillation. The laser contains first-line polarized light. When it passes through windows 31a and 31b, the linearly polarized light with a polarization direction different from that of the first-line polarized light is reduced from the laser. A portion of the laser passes through the output coupling mirror 70, is reflected by the high-reflectivity mirrors 141b and 141c, and then passes through the rear mirror 371 and window 331b, traveling into the housing 330.

[0094] The processor 190 switches on the pulse power module 343 to generate a discharge as the laser from the laser oscillator 130 travels into the discharge space within the housing 330. Specifically, the processor 190 controls the pulse power module 343 to apply a high voltage to electrodes 332a and 332b after a predetermined delay relative to the timing of switching on the pulse power module 43.

[0095] Thus, the laser incident on amplifier 160 is amplified in amplifier 160. Furthermore, the laser traveling into the interior space of housing 330, as described above, exits through window 331a and travels towards beam expander 400. The laser traveling towards beam expander 400 is reflected by convex mirror 410 towards concave mirror 420. The cross-sectional shape of the reflecting surface 411 in convex mirror 410 is an arc, and the focal line 410L of convex mirror 410 is contained in a plane that includes the optical axis LA1 of the laser and extends in the direction in which electrodes 332a and 332b are opposite each other. Therefore, the laser exiting from window 331a is reflected by convex mirror 410 towards concave mirror 420 in a manner that expands the beam width of the laser in a direction perpendicular to the direction in which electrodes 332a and 332b are opposite each other.

[0096] The laser beam, widened by the increased beam width, is reflected from the concave mirror 420 toward the output coupling mirror 370. The reflecting surface 421 in the concave mirror 420 has an arc-shaped cross-section. The focal lines 410L of the convex mirror 410 and 420L of the concave mirror 420 are contained in the same plane containing the optical axis LA1 of the laser, and the focal lines 410L and 420L are on the same straight line. Therefore, the laser beam, widened by the increased beam width, is reflected in the concave mirror 420 in a collimated manner, thus fixing the widened beam width. The collimated laser beam is then incident on the output coupling mirror 370.

[0097] A portion of the laser incident on the output coupling mirror 370 is reflected by the output coupling mirror 370 and then reflected by the concave mirror 420 toward the convex mirror 410. The beam width of the laser is reduced in a direction perpendicular to the direction in which the electrodes 332a and 332b are facing each other. The laser with the reduced beam width is reflected by the convex mirror 410 toward the window 331a. The laser is collimated in a fixed manner with the reduced beam width, travels through the window 331a into the interior space of the housing 330, and exits from the window 331b. The light exiting from the window 331b is reflected by the rear mirror 371 and travels through the window 331b into the interior space of the housing 330. In this way, the laser of a specified wavelength travels back and forth between the rear mirror 371 and the output coupling mirror 370. The laser is amplified each time it passes through the discharge space inside the housing 330, and a portion of the laser becomes amplified laser light.

[0098] In addition, the amplified laser from amplifier 160 travels through output coupling mirror 370 toward beam splitter 153b.

[0099] A portion of the amplified laser beam traveling toward the beam splitter 153b passes through the beam splitter 153b and the exit window 173 and travels toward the exposure device 200, while another portion is reflected by the beam splitter 153b and travels toward the photosensitive sensor 153c.

[0100] The optical sensor 153c measures the energy E of the received amplified laser. The optical sensor 153c outputs a signal representing the measured energy E to the processor 190. The processor 190 performs feedback control on the charging voltage of the chargers 41 and 341 to ensure that the difference ΔE between the energy E and the target energy Et is within an acceptable range. Laser with a difference ΔE within the acceptable range passes through the beam splitter 153b and the exit window 173 and enters the exposure apparatus 200.

[0101] 2.3 Research Topic

[0102] In the comparative example, the beam expander 400 expands the beam width of the laser emitted from the cavity device CH3 using a convex mirror 410 and a concave mirror 420, directing the light toward the output coupling mirror 370. Therefore, the energy density of the laser incident on the output coupling mirror 370 can be reduced, suppressing the time-dependent degradation of the output coupling mirror 370. Generally, the reflective surface of a light-reflecting component reflects most of the incident light; however, a portion of the light is not reflected at the reflective surface and passes through the reflective component. Therefore, a portion of the laser incident on the reflective surface 411 of the convex mirror 410 travels inside the convex mirror 410 and exits from the back surface 413 opposite to the reflective surface 411. Similarly, a portion of the laser incident on the reflective surface 421 of the concave mirror 420 travels inside the concave mirror 420 and exits from the back surface 423 opposite to the reflective surface 421. In the comparative example, the back surface 413 of the convex mirror 410 is fixed to the convex mirror holder 460 using adhesive 462, and the back surface 423 of the concave mirror 420 is fixed to the concave mirror holder 470 using adhesive 472. Therefore, laser irradiation of adhesives 462 and 472 can cause them to deteriorate, potentially reducing the durability of the gas laser device.

[0103] Therefore, in the following embodiments, a gas laser device capable of suppressing durability degradation is illustrated.

[0104] 3. Description of the gas laser device in Embodiment 1

[0105] Next, the gas laser device 100 of Embodiment 1 will be described. Furthermore, structures identical to those described above will be labeled with the same reference numerals, and repeated descriptions will be omitted unless specifically stated otherwise. Additionally, in some of the accompanying drawings, parts of components have been omitted or simplified for ease of observation.

[0106] 3.1 Structure

[0107] Figure 9 Is with Figure 3 Similarly, a schematic diagram of a schematic example of the beam expander 400 of Embodiment 1 is shown. Figure 9 As shown, in the beam expander 400 of this embodiment, the structures of the convex mirror holder 460 and the concave mirror holder 470 are different from those of the convex mirror holder 460 and the concave mirror holder 470 in the comparative example.

[0108] Figure 10 It is along Figure 9 The cross-sectional view of the beam expander 400 shown is a cross-sectional view of the beam expander 400 that runs parallel to the focal line 410L and crosses the convex mirror 410. For example... Figure 10As shown, the convex mirror holder 460 of this embodiment is a plate-shaped member extending along a specific side 412, which is one of two side 412 extending along the length direction of the convex mirror 410. Only one specific side 422 of the convex mirror 410 is fixed to the main surface 461 of the convex mirror holder 460 on the side adjacent to the convex mirror 410 using an adhesive 462. The adhesive 462 is separated into multiple adhesive portions. The adhesive 462 is disposed between the main surface 461 of the convex mirror holder 460 and the specific side 412 of the convex mirror 410, thereby separating the main surface 461 and the specific side 412, forming a space in the area between the main surface 461 and the specific side 412 where no adhesive 462 is disposed. Alternatively, the adhesive 462 may not be separated into multiple adhesive portions.

[0109] The convex mirror holder 460 includes a convex mirror protrusion 463 projecting from the main surface 461 and located around the convex mirror 410. The convex mirror protrusion 463 does not contact the convex mirror 410, which is surrounded by the convex mirror protrusion 463. Furthermore, the convex mirror protrusion 463 overlaps with the convex mirror 410 in a direction along a specific side surface 412.

[0110] The convex mirror holder 460 is fixed to the base member 451 with its main surface 464, on the side opposite to the convex mirror 410, abutting against the main surface 452 of the base member 451. In this embodiment, the convex mirror holder 460 is fixed to the base member 451 by an adhesive 453 disposed at the contact portions of a pair of opposing side surfaces 465 of the convex mirror holder 460 and the main surface 452 of the base member 451. Furthermore, the position of the adhesive 453 is not limited. For example, the adhesive 453 may also be disposed between the main surface 464 of the convex mirror holder 460 and the main surface 452 of the base member 451.

[0111] Preferably, the width 410W1 of the convex mirror 410 in the direction perpendicular to a specific side surface 412 of the convex mirror 410 is 10 mm or more and 40 mm or less; however, the width 410W1 is not limited. Furthermore, it is preferred that the width 410W2 of the convex mirror 410 in the direction along the edge 412e on the side of the reflecting surface 411 in the edge of the specific side surface 412 of the convex mirror 410 is 15 mm or more and 50 mm or less; however, the width 410W2 is not limited.

[0112] Figure 11 It is along Figure 9 The cross-sectional view of the beam expander 400 shown for the XI-XI line is a cross-sectional view of the beam expander 400 that crosses the concave mirror 420 parallel to the focal line 420L. For example... Figure 11As shown, the concave mirror holder 470 of this embodiment is a plate-shaped member extending along a specific side 422, which is one of two side 422 extending along the length direction of the concave mirror 420. Only one specific side 422 of the concave mirror 420 is fixed to the main surface 471 of the concave mirror holder 470 on the side adjacent to the concave mirror 420 using an adhesive 472. The adhesive 472 is separated into multiple adhesive portions. The adhesive 472 is disposed between the main surface 471 of the concave mirror holder 470 and the specific side 422 of the concave mirror 420, thereby separating the main surface 471 and the specific side 422, forming a space in the area between the main surface 471 and the specific side 422 where the adhesive 472 is not disposed. Alternatively, the adhesive 472 may not be separated into multiple adhesive portions.

[0113] The concave mirror holder 470 includes a concave mirror protrusion 473 that protrudes from the main surface 471 and is located around the concave mirror 420. The concave mirror protrusion 473 does not contact the concave mirror 420, which is surrounded by the concave mirror protrusion 473. Furthermore, the concave mirror protrusion 473 overlaps with the concave mirror 420 in a direction along a specific side surface 422.

[0114] The concave mirror holder 470 is fixed to the base member 451 with its main surface 474, on the side opposite to the concave mirror 420, abutting against the main surface 452 of the base member 451. In this embodiment, the concave mirror holder 470 is mechanically fixed to the main surface 452 of the base member 451 by two bolts 454 spaced apart from the concave mirror 420 in a direction parallel to the focal line 420L. Furthermore, the number and position of the bolts 454 are not limited. Moreover, the mechanical fixing is not limited to fixing based on bolts 454. For example, the concave mirror holder 470 can also be fixed to the main surface 452 of the base member 451 by hooks.

[0115] Preferably, the width 420W1 of the concave mirror 420 in the direction perpendicular to a specific side surface 422 of the concave mirror 420 is 10 mm or more and 40 mm or less; however, the width 420W1 is not limited. Furthermore, preferably, the width 420W2 of the concave mirror 420 in the direction along the edge 422e on the side of the reflecting surface 421 in the edge of the specific side surface 422 of the concave mirror 420 is 15 mm or more and 50 mm or less; however, the width 420W2 is not limited.

[0116] 3.2 Actions

[0117] In the beam expander 400 of this embodiment, similar to the beam expander 400 of the comparative example, the laser emitted from the window 331a of the cavity device CH3 is reflected sequentially by the convex mirror 410 and the concave mirror 420, and the beam width of the laser is expanded in a direction perpendicular to the direction opposite to the electrodes 332a and 332b. Then, the laser with expanded beam width is incident on the output coupling mirror 370. A portion of the laser incident on the output coupling mirror 370 is reflected by the output coupling mirror 370. The laser reflected by the output coupling mirror 370 is reflected sequentially by the concave mirror 420 and the convex mirror 410, and the beam width of the laser is reduced in a direction perpendicular to the direction opposite to the electrodes 332a and 332b. The laser with reduced beam width travels through the window 331a into the interior space of the housing 330 and is emitted from the window 331b. The light emitted from the window 331b is reflected by the rear mirror 371 and travels through the window 331b into the interior space of the housing 330. In this way, the laser travels back and forth between the rear mirror 371 and the output coupling mirror 370, and is amplified each time it passes through the discharge space inside the housing 330.

[0118] 3.3 Functions / Effects

[0119] In the beam expander 400 of this embodiment, similar to the beam expander 400 of the comparative example, the energy density of the laser incident on the output coupling mirror 370 can be reduced, suppressing the time-related degradation of the output coupling mirror 370. Furthermore, in the beam expander 400 of this embodiment, only one specific side 412 of the convex mirror 410 is fixed to the convex mirror holder 460 using adhesive 462, and only one specific side 422 of the concave mirror 420 is fixed to the concave mirror holder 470 using adhesive 472. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the back surface 413 of the convex mirror 410 is fixed to the convex mirror holder 460 using adhesive 462, it is possible to suppress the laser light incident from the reflecting surface 411 of the convex mirror 410 and transmitted through the convex mirror 410 from irradiating the adhesive 462. Furthermore, compared to the case where the back surface 423 of the concave mirror 420 is fixed to the concave mirror holder 470 using adhesive 472, it is possible to suppress the irradiation of the adhesive 472 by laser light incident from the reflecting surface 421 of the concave mirror 420 and passing through the concave mirror 420. Therefore, according to the gas laser device 100 of this embodiment, it is possible to suppress the deterioration of the adhesive 462 and 472 caused by the laser, and to suppress the decrease in the durability of the gas laser device 100. Generally, adhesives shrink during curing; however, due to manufacturing errors, there is a tendency for the thickness of the applied adhesive to deviate depending on the application position. Therefore, there is a tendency for the amount of shrinkage of the adhesive to deviate depending on the application position. Therefore, when the back surface 413 of the convex mirror 410 is fixed with adhesive 462, there is a concern that the reflecting surface 411 may deform due to deviations in the amount of shrinkage of adhesive 462. Similarly, when the back surface 423 of the concave mirror 420 is fixed with adhesive 472, there is a concern that the reflecting surface 421 may deform due to deviations in the amount of shrinkage of adhesive 472. There is a tendency that, in the deformation of the reflecting surfaces 411 and 421, the greater the deformation in the direction perpendicular to each reflecting surface 411 and 421, the greater the impact on the laser beam profile. In the beam expander 400 of this embodiment, as described above, only one specific side surface 412 of the convex mirror 410 is fixed with adhesive 462, and only one specific side surface 422 of the concave mirror 420 is fixed with adhesive 472. Therefore, the shrinkage direction of adhesive 462 can approach the direction parallel to the reflecting surface 411 of the convex mirror 410, and the shrinkage direction of adhesive 472 can approach the direction parallel to the reflecting surface 421 of the concave mirror 420. Therefore, according to the gas laser device 100 of this embodiment, deformation of the reflecting surface 411 in the direction perpendicular to the reflecting surface 411 and deformation of the reflecting surface 421 in the direction perpendicular to the reflecting surface 421 can be suppressed, thereby suppressing the influence on the laser beam profile.

[0120] In the beam expander 400 of this embodiment, the convex mirror holder 460 includes a convex mirror protrusion 463 that protrudes from the main surface 461 and is located around the convex mirror 410. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the convex mirror holder 460 does not include the convex mirror protrusion 463, it is possible to suppress scattered light from irradiating the adhesive 462 and causing the adhesive 462 to deteriorate. Alternatively, the convex mirror holder 460 may also omit the convex mirror protrusion 463.

[0121] In the beam expander 400 of this embodiment, the convex mirror 410 is surrounded by the convex mirror protrusion 463. Therefore, according to the gas laser device 100 of this embodiment, compared with the case where the convex mirror 410 is not surrounded by the convex mirror protrusion 463, it is possible to suppress the scattered light from irradiating the adhesive 462 and causing the adhesive 462 to deteriorate.

[0122] In the beam expander 400 of this embodiment, the convex mirror protrusion 463 overlaps with the convex mirror 410 in a direction along a specific side surface 412 fixed by adhesive 462 within the convex mirror 410. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the convex mirror protrusion 463 does not overlap with the convex mirror 410 in the aforementioned direction, it is possible to suppress scattered light from irradiating the adhesive 462 and causing degradation of the adhesive 462. Alternatively, the convex mirror protrusion 463 may not overlap with the convex mirror 410 in the aforementioned direction.

[0123] In the beam expander 400 of this embodiment, the concave mirror holder 470 includes a concave mirror protrusion 473 that protrudes from the main surface 471 and is located around the concave mirror 420. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the concave mirror holder 470 does not include the concave mirror protrusion 473, it is possible to suppress scattered light from irradiating the adhesive 472 and causing the adhesive 472 to deteriorate. Alternatively, the concave mirror holder 470 may also omit the concave mirror protrusion 473.

[0124] In the beam expander 400 of this embodiment, the concave mirror 420 is surrounded by the concave mirror protrusion 473. Therefore, according to the gas laser device 100 of this embodiment, compared with the case where the concave mirror 420 is not surrounded by the concave mirror protrusion 473, it is possible to suppress the scattered light from irradiating the adhesive 472 and causing the adhesive 472 to deteriorate.

[0125] In the beam expander 400 of this embodiment, the protrusion 473 for the concave mirror overlaps with the concave mirror 420 in a direction along a specific side surface 422 of the concave mirror 420 that is fixed by the adhesive 472. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the protrusion 473 for the concave mirror does not overlap with the concave mirror 420 in the aforementioned direction, it is possible to suppress scattered light from irradiating the adhesive 472 and causing the adhesive 472 to deteriorate. Alternatively, the protrusion 473 for the concave mirror may not overlap with the concave mirror 420 in the aforementioned direction.

[0126] In this embodiment, the convex mirror 410 is not in contact with and is surrounded by the convex mirror protrusion 463, and the concave mirror 420 is not in contact with and is surrounded by the concave mirror protrusion 473. However, the convex mirror protrusion 463 and the convex mirror 410 may also be in contact with each other, and the concave mirror protrusion 473 and the concave mirror 420 may also be in contact with each other. However, at least one of the convex mirror protrusion 463 and the convex mirror 410, and the concave mirror protrusion 473 and the concave mirror 420 may not be in contact with each other. Furthermore, the convex mirror 410 may not be surrounded by the convex mirror protrusion 463, and the concave mirror 420 may not be surrounded by the concave mirror protrusion 473. However, it is preferable that at least one of the convex mirror 410 and the concave mirror 420 is surrounded by the corresponding protrusion of the convex mirror protrusion 463 and the concave mirror protrusion 473. In addition, the protrusion corresponding to the convex mirror 410 is a convex mirror protrusion 463, and the protrusion corresponding to the concave mirror 420 is a concave mirror protrusion 473.

[0127] In this embodiment, only a specific side 412 extending along the length direction of the convex mirror 410 is fixed using adhesive 462, and only a specific side 422 extending along the length direction of the concave mirror 420 is fixed using adhesive 472. However, the side 412 of the convex mirror 410 fixed using adhesive 462 and the side 422 of the concave mirror 420 fixed using adhesive 472 are not limited to the specific side 412 and 422 described above. For example, it is also possible that only a side 412 extending along the short side direction of the convex mirror 410 is fixed using adhesive 462, and only a side 422 extending along the short side direction of the concave mirror 420 is fixed using adhesive 472.

[0128] In this embodiment, the retaining portion 450 includes a base component 451, a convex mirror retainer 460, and a concave mirror retainer 470. However, the retaining portion 450 is not limited as long as only one side 412 of the convex mirror 410 is fixed with adhesive 462 and only one side 422 of the concave mirror 420 is fixed with adhesive 472. For example, the retaining portion 450 may not include the convex mirror retainer 460 and the concave mirror retainer 470. In this case, for example, only one side 412 of the convex mirror 410 is fixed to the main surface 452 of the base component 451 with adhesive 462, and only one side 422 of the concave mirror 420 is fixed to the main surface 452 of the base component 451 with adhesive 472. In this case, the base component 451 may also include at least one of the convex mirror protrusion 463 and the concave mirror protrusion 473.

[0129] In this embodiment, the convex mirror holder 460 is fixed to the main surface 452 of the base component 451 using adhesive 453, and the concave mirror holder 470 is mechanically fixed to the main surface 452 of the base component 451. However, the method of fixing the convex mirror holder 460 and the concave mirror holder 470 to the base component 451 is not limited. For example, at least one of the convex mirror holder 460 and the concave mirror holder 470 may be fixed to the base component 451 using adhesive. Alternatively, one of the convex mirror holder 460 and the concave mirror holder 470 may be fixed to the base component 451 using adhesive, while the other may be mechanically fixed to the base component 451.

[0130] 4. Description of the gas laser device in Embodiment 2

[0131] Next, the gas laser device 100 of Embodiment 2 will be described. Furthermore, structures identical to those described above will be labeled with the same reference numerals, and repeated descriptions will be omitted unless specifically stated otherwise. Additionally, in some of the accompanying drawings, parts of components have been omitted or simplified for ease of observation.

[0132] 4.1 Structure

[0133] Figure 12 Is with Figure 3 Similarly, a schematic diagram of a schematic example of the beam expander 400 of this embodiment is shown. Figure 12 As shown, the main difference between the beam expander 400 of this embodiment and the beam expander 400 of Embodiment 1 is that it also includes a plane mirror 430, and the holding part 450 also includes a plane mirror holder 480.

[0134] Figure 13 Is with Figure 4 Similarly, perspective views of the convex mirror 410, plane mirror 430, and concave mirror 420 of this embodiment are shown. Figure 12 and Figure 13 As shown, in this embodiment, the convex mirror 410 reflects the laser from the cavity device CH3 toward the plane mirror 430. The plane mirror 430 is a plate-shaped component, including a reflective surface 431 that reflects light, multiple side surfaces 432, and a back surface 433 located inside the reflective surface 431 and opposite to it. The reflective surface 431 of the plane mirror 430 reflects the laser reflected by the convex mirror 410 toward the concave mirror 420. The concave mirror 420 reflects the laser reflected by the plane mirror 430 toward the output coupling mirror 370. Furthermore, the concave mirror 420 reflects the laser reflected by the output coupling mirror 370 toward the plane mirror 430, the plane mirror 430 reflects the laser reflected by the concave mirror 420 toward the convex mirror 410, and the convex mirror 410 reflects the laser reflected by the plane mirror 430 toward the cavity device CH3.

[0135] The focal line 410L of the convex mirror 410 is contained in a plane extending in the direction in which the laser beam contains the optical axis LA1 and the electrodes 332a and 332b are opposite each other, and is tilted towards the electrode 332a side as it moves away from the cavity device CH3. Similarly, the focal line 420L of the concave mirror 420 is contained in the plane containing the laser beam contains the optical axis LA1 and the focal line 410L, and is tilted towards the electrode 332b side as it moves away from the cavity device CH3. Furthermore, the focal line 410Lv of the virtual image 410v of the convex mirror 410 generated by the reflecting surface 431 of the plane mirror 430 and the focal line 420L of the concave mirror 420 are on the same straight line. Moreover, the optical axis LA1 of the laser beam from the cavity device CH3 toward the convex mirror 410 and the optical axis LA2 of the laser beam from the concave mirror 420 toward the output coupling mirror 370 are on the same straight line. In other words, the positions of the convex mirror 410, the plane mirror 430, and the concave mirror 420 are thus adjusted. Figure 12 In the diagram, the virtual image 410v and its focal line 410Lv are shown using dashed lines.

[0136] In this embodiment, when the reflecting surface 431 is viewed from the front, the plane mirror 430 is a rectangle that is longer in the direction parallel to the optical axis LA1 of the laser from the cavity device CH3. Therefore, the plane mirror 430 includes four planar side surfaces 432. Furthermore, the shape of the plane mirror 430 and the number of side surfaces 432 are not limited. For example, the shape of the plane mirror 430 may also be a rectangle that is longer in the direction perpendicular to the optical axis LA1.

[0137] Figure 14 It is along Figure 12 The cross-sectional view of the beam expander 400 along the XIV-XIV line shown is a cross-sectional view of the beam expander 400 that runs parallel to the reflecting surface 431 and traverses the plane mirror 430. For example... Figure 14As shown, the plane mirror holder 480 of this embodiment is a plate-shaped member extending along a specific side 432, which is one of two side 432 extending along the length direction of the plane mirror 430. Only one specific side 432 of the plane mirror 430 is fixed to the main surface 481 of the plane mirror holder 480 on the side adjacent to the plane mirror 430 using an adhesive 482. The adhesive 482 is separated into multiple adhesive portions. The adhesive 482 is disposed between the main surface 481 of the plane mirror holder 480 and the specific side 432 of the plane mirror 430, thereby separating the main surface 481 and the specific side 432, forming a space between the main surface 481 and the specific side 432 where no adhesive 482 is disposed. As an adhesive 482, for example, the same adhesive as adhesive 462 is used. Alternatively, the adhesive 482 may not be separated into multiple adhesive portions.

[0138] The plane mirror holder 480 includes a plane mirror protrusion 483 that protrudes from the main surface 481 and is located around the plane mirror 430. The plane mirror protrusion 483 does not contact the plane mirror 430, which is surrounded by the plane mirror protrusion 483. Furthermore, the plane mirror protrusion 483 overlaps with the plane mirror 430 in a direction along a specific side surface 432.

[0139] The plane mirror holder 480 is fixed to the base member 451 with its main surface 484, on the side opposite to the plane mirror 430, abutting against the main surface 452 of the base member 451. In this embodiment, similar to the concave mirror holder 470 in Embodiment 1, the concave mirror holder 470 is mechanically fixed to the main surface 452 of the base member 451 by two bolts 454. Furthermore, the number and position of the bolts 454 are not limited. Moreover, the mechanical fixing is not limited to fixing based on bolts 454. For example, the plane mirror holder 480 can also be fixed to the main surface 452 of the base member 451 by hooks.

[0140] Preferably, the width 430W1 of the plane mirror 430 in the direction perpendicular to a specific side surface 432 of the plane mirror 430 is 10 mm or more and 40 mm or less; however, the width 430W1 is not limited. Furthermore, preferably, the width 430W2 of the plane mirror 430 in the direction along the edge 432e on the side of the reflecting surface 431 in the edge of the specific side surface 432 of the plane mirror 430 is 15 mm or more and 50 mm or less; however, the width 430W2 is not limited.

[0141] Similar to the concave mirror holder 470 in Embodiment 1, the convex mirror holder 460 in this embodiment is mechanically fixed to the main surface 452 of the base member 451 by two bolts 454. Furthermore, the number and position of the bolts 454 are not limited. Moreover, the mechanical fixing is not limited to fixing based on bolts 454. For example, the convex mirror holder 460 can also be fixed to the main surface 452 of the base member 451 by hooks.

[0142] Similar to the convex mirror holder 460 of Embodiment 1, the concave mirror holder 470 of this embodiment is fixed to the base member 451 by an adhesive 453. Furthermore, the position of the adhesive 453 is not limited. For example, the adhesive 453 may also be disposed between the main surface 474 of the concave mirror holder 470 and the main surface 452 of the base member 451.

[0143] 4.2 Actions

[0144] Similar to Embodiment 1, the laser emitted from window 331a is reflected by convex mirror 410, and the beam width of the laser is expanded in a direction perpendicular to the direction opposite to electrodes 332a and 332b. This expanded beam width laser is reflected by the reflecting surface 431 of plane mirror 430 towards concave mirror 420. As described above, the focal line 410Lv of the virtual image 410v and the focal line 420L of the concave mirror 420 are on the same straight line. Therefore, the laser reflected by plane mirror 430 is collimated and reflected by concave mirror 420, fixing the expanded beam width through this collimation. The collimated laser is then incident on output coupling mirror 370.

[0145] Furthermore, the laser beam reflected by the output coupling mirror 370 is reflected by the concave mirror 420 towards the plane mirror 430. The beam width of this laser is reduced in a direction perpendicular to the direction in which the electrodes 332a and 332b are facing each other. The laser beam with reduced width is reflected by the plane mirror 430 towards the convex mirror 410, and the laser beam reflected by the plane mirror 430 is reflected by the convex mirror 410 towards the window 331a. The laser is collimated in a fixed manner with a reduced beam width and returns to the interior space of the housing 330 via the window 331a.

[0146] 4.3 Functions / Effects

[0147] The gas laser device 100 according to this embodiment, similar to the gas laser device 100 of Embodiment 1, can reduce the energy density of the laser incident on the output coupling mirror 370, thus suppressing the time-related degradation of the output coupling mirror 370. Furthermore, in the beam expander 400 of this embodiment, only one specific side 432 of the plane mirror 430 is fixed to the plane mirror holder 480 using adhesive 472. Therefore, compared to the case where the back surface 433 of the plane mirror 430 is fixed to the plane mirror holder 480 using adhesive 482, the gas laser device 100 according to this embodiment can suppress the irradiation of the adhesive 482 by laser light incident from the reflecting surface 431 of the plane mirror 430 and transmitted through the plane mirror 430. Therefore, the gas laser device 100 according to this embodiment can suppress the degradation of the adhesive 482 caused by the laser, and can suppress the decrease in the durability of the gas laser device 100. Furthermore, the gas laser device 100 according to this embodiment, like the convex mirror 410 and concave mirror 420 of Embodiment 1, can suppress the deformation of the reflecting surface 431 in the direction perpendicular to the reflecting surface 431, and can suppress the influence on the beam profile of the laser.

[0148] In the beam expander 400 of this embodiment, the plane mirror holder 480 includes a plane mirror protrusion 483 that protrudes from the main surface 481 and is located around the plane mirror 430. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the plane mirror holder 480 does not include the plane mirror protrusion 483, it is possible to suppress scattered light from irradiating the adhesive 482 and causing the adhesive 482 to deteriorate. Alternatively, the plane mirror holder 480 may also omit the plane mirror protrusion 483.

[0149] In the beam expander 400 of this embodiment, the plane mirror 430 is surrounded by the plane mirror protrusion 483. Therefore, according to the gas laser device 100 of this embodiment, compared with the case where the plane mirror 430 is not surrounded by the plane mirror protrusion 483, it is possible to suppress the scattered light from irradiating the adhesive 482 and causing the adhesive 482 to deteriorate.

[0150] In the beam expander 400 of this embodiment, the protrusion 483 for the plane mirror overlaps with the plane mirror 430 in a direction along a specific side 432 of the plane mirror 430 that is fixed by adhesive 482. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the protrusion 483 for the plane mirror does not overlap with the plane mirror 430 in the aforementioned direction, it is possible to suppress scattered light from irradiating the adhesive 482 and causing the adhesive 482 to deteriorate. Alternatively, the protrusion 483 for the plane mirror may not overlap with the plane mirror 430 in the aforementioned direction.

[0151] In this embodiment, the plane mirror 430 is not in contact with and is surrounded by the plane mirror protrusion 483; however, the plane mirror protrusion 483 and the plane mirror 430 may also be in contact with each other. However, at least one of the following: the convex mirror protrusion 463 and the convex mirror 410; the concave mirror protrusion 473 and the concave mirror 420; and the plane mirror protrusion 483 and the plane mirror 430 may also not be in contact with each other. Furthermore, it is preferable that at least one of the convex mirror 410, the concave mirror 420, and the plane mirror 430 is surrounded by a corresponding protrusion among the convex mirror protrusion 463, the concave mirror protrusion 473, and the plane mirror protrusion 483. Additionally, the protrusion corresponding to the convex mirror 410 is the convex mirror protrusion 463, the protrusion corresponding to the concave mirror 420 is the concave mirror protrusion 473, and the protrusion corresponding to the plane mirror 430 is the plane mirror protrusion 483.

[0152] In this embodiment, only a specific side 432 extending along the length direction of the plane mirror 430 is fixed using adhesive 482. However, the side 432 of the plane mirror 430 fixed using adhesive 482 is not limited to the specific side 432 described above. For example, it is also possible that only a side 432 extending along the short side direction of the plane mirror 430 is fixed using adhesive 482.

[0153] In this embodiment, the retaining portion 450 includes a base component 451, a convex mirror retainer 460, a concave mirror retainer 470, and a plane mirror retainer 480. However, the retaining portion 450 is not limited as long as only one side 412 of the convex mirror 410 is fixed with adhesive 462, only one side 422 of the concave mirror 420 is fixed with adhesive 472, and only one side 432 of the plane mirror 430 is fixed with adhesive 482. For example, the retaining portion 450 may not include the plane mirror retainer 480. In this case, for example, only one side 432 of the plane mirror 430 is fixed to the main surface 452 of the base component 451 with adhesive 482. In this case, the base component 451 may also include a protrusion 483 for the plane mirror.

[0154] In this embodiment, the convex mirror holder 460 and the plane mirror holder 480 are mechanically fixed to the main surface 452 of the base component 451, and the concave mirror holder 470 is fixed to the main surface 452 of the base component 451 using an adhesive 453. However, the method of fixing the convex mirror holder 460, the concave mirror holder 470, and the plane mirror holder 480 to the base component 451 is not limited. For example, at least one of the convex mirror holder 460 and the concave mirror holder 470 may be fixed to the base component 451 using an adhesive. Alternatively, one of the convex mirror holder 460 and the concave mirror holder 470 may be fixed to the base component 451 using an adhesive, while the other is mechanically fixed to the base component 451. Furthermore, the plane mirror holder 480 may also be fixed to the base component 451 using an adhesive.

[0155] In this embodiment, the focal line 410Lv and the focal line 420L in the virtual image 410v are located on the same straight line. However, the focal line 410Lv and the focal line 420Lv may not be located on the same straight line.

[0156] In this embodiment, the optical axis LA1 of the laser beam from the cavity device CH3 toward the convex mirror 410 and the optical axis LA2 of the laser beam from the concave mirror 420 toward the output coupling mirror 370 are on the same straight line. Therefore, for example, even without changing the design positions of the cavity device CH3 and the output coupling mirror 370, the beam expander 400 can be configured in the existing amplifier 160. Alternatively, the optical axes LA1 and LA2 may not be on the same straight line.

[0157] 5. Description of the gas laser device in Embodiment 3

[0158] Next, the gas laser device 100 of Embodiment 3 will be described. Furthermore, structures identical to those described above will be labeled with the same reference numerals, and repeated descriptions will be omitted unless specifically stated otherwise. Additionally, in some of the accompanying drawings, parts of components have been omitted or simplified for ease of observation.

[0159] 5.1 Structure

[0160] Figure 15 Is with Figure 3 Similarly, a schematic diagram of a schematic example of the beam expander 400 of this embodiment is shown. Figure 15 As shown, the main difference between the beam expander 400 of this embodiment and the beam expander 400 of embodiment 2 is that it also includes a plane mirror 440, and the holding part 450 also includes a plane mirror holder 490.

[0161] Figure 16 Is with Figure 4Similarly, perspective views of the convex mirror 410, the two plane mirrors 430 and 440, and the concave mirror 420 of this embodiment are shown. Hereinafter, plane mirror 430 will be referred to as the first plane mirror, plane mirror 440 as the second plane mirror, plane mirror holder 480 as the first plane mirror holder, plane mirror holder 490 as the second plane mirror holder, and plane mirror protrusion 483 as the first plane mirror protrusion.

[0162] In this embodiment, the convex mirror 410 reflects the laser from the cavity device CH3 toward the first plane mirror 430. The first plane mirror 430 reflects the laser reflected by the convex mirror 410 toward the second plane mirror 440. The second plane mirror 440 is a plate-shaped component, including a reflective surface 441 that reflects light, a plurality of side surfaces 442, and a back surface 443 located inside the reflective surface 441 and opposite to it. The reflective surface 441 of the second plane mirror 440 reflects the laser reflected by the first plane mirror 430 toward the concave mirror 420. The concave mirror 420 reflects the laser reflected by the second plane mirror 440 toward the output coupling mirror 370. Furthermore, the concave mirror 420 reflects the laser reflected by the output coupling mirror 370 toward the second plane mirror 440, and the second plane mirror 440 reflects the laser reflected by the concave mirror 420 toward the first plane mirror 430. The first plane mirror 430 causes the laser light reflected by the second plane mirror 440 to be reflected towards the convex mirror 410, and the convex mirror 410 causes the laser light reflected by the first plane mirror 430 to be reflected towards the cavity device CH3.

[0163] The focal line 410L of the convex mirror 410 is contained in a plane extending in the direction in which the laser beam contains the optical axis LA1 and the electrodes 332a and 332b are opposite each other, and is tilted towards the electrode 332a side as it moves away from the cavity device CH3. Similarly, the focal line 420L of the concave mirror 420 is contained in the plane containing the laser beam contains the optical axis LA1 and the focal line 410L, and is tilted towards the electrode 332b side as it moves away from the cavity device CH3. Furthermore, the focal line 410Lv of the virtual image 410v of the convex mirror 410 generated by the reflecting surface 431 of the first plane mirror 430 and the focal line 420Lv of the virtual image 420v of the concave mirror 420 generated by the reflecting surface 441 of the second plane mirror 440 are located on the same straight line. Additionally, the optical axis LA1 of the laser beam from the cavity device CH3 toward the convex mirror 410 and the optical axis LA2 of the laser beam from the concave mirror 420 toward the output coupling mirror 370 are located on the same straight line. That is, the positions of the convex mirror 410, the first plane mirror 430, the second plane mirror 440, and the concave mirror 420 are thus adjusted. Figure 15 In the image, the virtual image 410v and its focal line 410Lv, the virtual image 420v and its focal line 420Lv are shown using dashed lines.

[0164] In this embodiment, when the reflecting surface 441 is viewed from the front, the second plane mirror 440 is a rectangle that is longer in the direction parallel to the optical axis LA1 of the laser from the cavity device CH3. Therefore, the second plane mirror 440 includes four planar side surfaces 442. Furthermore, the shape of the second plane mirror 440 and the number of side surfaces 442 are not limited. For example, the shape of the second plane mirror 440 may also be a rectangle that is longer in the direction perpendicular to the optical axis LA1.

[0165] Figure 17 It is along Figure 15 The cross-sectional view of the beam expander 400 along line XVII-XVII shown is a cross-sectional view of the beam expander 400 that traverses the second plane mirror 440 parallel to the reflecting surface 441. (As shown...) Figure 17 As shown, the second plane mirror holder 490 of this embodiment is a plate-shaped member extending along a specific side 442, which is one of two side 442s extending along the length direction of the second plane mirror 440. Only one specific side 442 of the second plane mirror 440 is fixed to the main surface 491 of the second plane mirror holder 490 on the side adjacent to the second plane mirror 440 using an adhesive 492. The adhesive 492 is separated into multiple adhesive portions. The adhesive 492 is disposed between the main surface 491 of the second plane mirror holder 490 and the specific side 442 of the second plane mirror 440, thereby separating the main surface 491 and the specific side 442, forming a space between the main surface 491 and the specific side 442 where no adhesive 492 is disposed. For example, the same adhesive as adhesive 462 is used as the adhesive 492. Alternatively, the adhesive 492 may not be separated into multiple adhesive portions.

[0166] The second plane mirror holder 490 includes a second plane mirror protrusion 493 protruding from the main surface 491 and located around the second plane mirror 440. The second plane mirror protrusion 493 does not contact the second plane mirror 440, but is surrounded by the second plane mirror protrusion 493. Furthermore, the second plane mirror protrusion 493 overlaps with the second plane mirror 440 in a direction along a specific side surface 442.

[0167] The second plane mirror holder 490 is fixed to the base member 451 with its main surface 494, on the side opposite to the second plane mirror 440, abutting against the main surface 452 of the base member 451. In this embodiment, similar to the concave mirror holder 470 in Embodiment 1, the concave mirror holder 470 is mechanically fixed to the main surface 452 of the base member 451 by two bolts 454. Furthermore, the number and position of the bolts 454 are not limited. Moreover, the mechanical fixing is not limited to fixing based on bolts 454. For example, the second plane mirror holder 490 can also be fixed to the main surface 452 of the base member 451 by hooks.

[0168] Preferably, the width 440W1 of the second plane mirror 440 in the direction perpendicular to a specific side surface 442 of the second plane mirror 440 is 10 mm or more and 40 mm or less; however, the width 440W1 is not limited. Furthermore, preferably, the width 440W2 of the second plane mirror 440 in the direction along the edge 442e on the side of the reflecting surface 441 in the edge of the specific side surface 442 of the second plane mirror 440 is 15 mm or more and 50 mm or less; however, the width 440W2 is not limited.

[0169] Similar to the convex mirror holder 460 of Embodiment 1, the convex mirror holder 460 of this embodiment is fixed to the base member 451 by an adhesive 453. Furthermore, the position of the adhesive 453 is not limited. For example, the adhesive 453 may also be disposed between the main surface 464 of the convex mirror holder 460 and the main surface 452 of the base member 451.

[0170] Similar to the concave mirror holder 470 in Embodiment 1, the concave mirror holder 470, the first plane mirror holder 480, and the second plane mirror holder 490 in this embodiment are mechanically fixed to the main surface 452 of the base component 451 by two bolts 454. Furthermore, the number and position of the bolts 454 are not limited. Moreover, the mechanical fixing is not limited to fixing based on bolts 454. For example, the concave mirror holder 470, the first plane mirror holder 480, and the second plane mirror holder 490 can also be fixed to the main surface 452 of the base component 451 by hooks.

[0171] 5.2 Actions

[0172] Similar to Embodiment 2, the laser emitted from window 331a is reflected by convex mirror 410, and the laser beam width is expanded in a direction perpendicular to the direction opposite to electrodes 332a and 332b. The laser with expanded beam width is reflected from first plane mirror 430 toward second plane mirror 440, and the laser reflected from first plane mirror 430 is reflected from the reflecting surface 441 of second plane mirror 440 toward concave mirror 420. As described above, the focal line 410Lv of virtual image 410v and the focal line 420Lv of virtual image 420v are on the same straight line. Therefore, the laser reflected from second plane mirror 440 is collimated and reflected in concave mirror 420, and this collimation fixes the expanded beam width. The collimated laser is then incident on output coupling mirror 370.

[0173] Furthermore, the laser beam reflected by the output coupling mirror 370 is reflected by the concave mirror 420 towards the second plane mirror 440. The beam width of this laser is reduced in a direction perpendicular to the direction in which the electrodes 332a and 332b are facing each other. The laser beam with reduced width is reflected by the second plane mirror 440 towards the first plane mirror 430, and the laser beam reflected by the second plane mirror 440 is reflected by the first plane mirror 430 towards the concave mirror 420. The laser beam reflected by the first plane mirror 430 is reflected by the convex mirror 410 towards the window 331a. The laser is collimated in a fixed manner with a reduced beam width and returns to the interior space of the housing 330 via the window 331a.

[0174] 5.3 Functions / Effects

[0175] The gas laser device 100 according to this embodiment, similar to the gas laser device 100 of Embodiment 1, can reduce the energy density of the laser incident on the output coupling mirror 370, thus suppressing the time-related degradation of the output coupling mirror 370. Furthermore, in the beam expander 400 of this embodiment, only a specific side 442 of the second plane mirror 440 is fixed to the second plane mirror holder 490 using adhesive 492. Therefore, compared to the case where the back surface 443 of the second plane mirror 440 is fixed to the plane mirror holder 490 using adhesive 492, the gas laser device 100 according to this embodiment can suppress the irradiation of the adhesive 492 by laser light incident from the reflecting surface 441 of the second plane mirror 440 and transmitted through the second plane mirror 440. Therefore, the gas laser device 100 according to this embodiment can suppress the degradation of the adhesive 492 caused by the laser, and can suppress the decrease in the durability of the gas laser device 100. Furthermore, the gas laser device 100 according to this embodiment, like the convex mirror 410 and concave mirror 420 of Embodiment 1, can suppress the deformation of the reflecting surface 441 in the direction perpendicular to the reflecting surface 441, and can suppress the influence on the beam profile of the laser.

[0176] In the beam expander 400 of this embodiment, the second plane mirror holder 490 includes a second plane mirror protrusion 493 that protrudes from the main surface 491 and is located around the second plane mirror 440. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the second plane mirror holder 490 does not include the second plane mirror protrusion 493, it is possible to suppress scattered light from irradiating the adhesive 492 and causing the adhesive 492 to deteriorate. Alternatively, the second plane mirror holder 490 may also omit the second plane mirror protrusion 493.

[0177] In the beam expander 400 of this embodiment, the second plane mirror 440 is surrounded by the second plane mirror protrusion 493. Therefore, according to the gas laser device 100 of this embodiment, compared with the case where the second plane mirror 440 is not surrounded by the second plane mirror protrusion 493, it is possible to suppress the scattered light from irradiating the adhesive 492 and causing the adhesive 492 to deteriorate.

[0178] In the beam expander 400 of this embodiment, the protrusion 493 for the second plane mirror overlaps with the second plane mirror 440 in a direction along a specific side 442 of the second plane mirror 440 that is fixed by adhesive 492. Therefore, according to the gas laser device 100 of this embodiment, compared to the case where the protrusion 493 for the second plane mirror does not overlap with the second plane mirror 440 in the aforementioned direction, it is possible to suppress scattered light from irradiating the adhesive 492 and causing the adhesive 492 to deteriorate. Alternatively, the protrusion 483 for the plane mirror may also not overlap with the second plane mirror 440 in the aforementioned direction.

[0179] In this embodiment, the second plane mirror 440 is not in contact with and is surrounded by the second plane mirror protrusion 493. However, the second plane mirror protrusion 493 and the second plane mirror 440 may also be in contact with each other. However, at least one of the following may also not be in contact: the convex mirror protrusion 463 with the convex mirror 410, the concave mirror protrusion 473 with the concave mirror 420, the first plane mirror protrusion 483 with the first plane mirror 430, and the second plane mirror protrusion 493 with the second plane mirror 440. Furthermore, it is preferable that at least one of the convex mirror 410, the concave mirror 420, the first plane mirror 430, and the second plane mirror 440 is surrounded by a corresponding protrusion of the convex mirror protrusion 463, the concave mirror protrusion 473, the first plane mirror protrusion 483, and the second plane mirror protrusion 493. In addition, the protrusion corresponding to the convex mirror 410 is a convex mirror protrusion 463, the protrusion corresponding to the concave mirror 420 is a concave mirror protrusion 473, the protrusion corresponding to the first plane mirror 430 is a first plane mirror protrusion 483, and the protrusion corresponding to the second plane mirror 440 is a second plane mirror protrusion 493.

[0180] In this embodiment, only a specific side 442 extending along the length direction of the second plane mirror 440 is fixed using adhesive 492. However, the side 442 of the second plane mirror 440 fixed using adhesive 492 is not limited to the specific side 442 described above. For example, it is also possible that only one side 442 extending along the short side direction of the second plane mirror 440 is fixed using adhesive 492.

[0181] In this embodiment, the retaining portion 450 includes a base component 451, a convex mirror retainer 460, a concave mirror retainer 470, a first plane mirror retainer 480, and a second plane mirror retainer 490. However, the retaining portion 450 is not limited as long as only one side 412 of the convex mirror 410 is fixed with adhesive 462, only one side 422 of the concave mirror 420 is fixed with adhesive 472, only one side 432 of the first plane mirror 430 is fixed with adhesive 492, and only one side 442 of the second plane mirror 440 is fixed with adhesive 492. For example, the retaining portion 450 may not include the second plane mirror retainer 490. In this case, for example, only one side 442 of the second plane mirror 440 is fixed to the main surface 452 of the base component 451 with adhesive 492, and the base component 451 may also include a protrusion 493 for the second plane mirror.

[0182] In this embodiment, the convex mirror holder 460 is fixed to the main surface 452 of the base component 451 using adhesive 453, and the concave mirror holder 470, the first plane mirror holder 480, and the second plane mirror holder 490 are mechanically fixed to the main surface 452 of the base component 451. However, the method of fixing the convex mirror holder 460, the concave mirror holder 470, the first plane mirror holder 480, and the second plane mirror holder 490 to the base component 451 is not limited. For example, at least one of the convex mirror holder 460 and the concave mirror holder 470 may be fixed to the base component 451 using adhesive. Alternatively, one of the convex mirror holder 460 and the concave mirror holder 470 may be fixed to the base component 451 using adhesive, while the other may be mechanically fixed to the base component 451. In addition, the second plane mirror holder 490 can also be fixed to the base component 451 using an adhesive.

[0183] In the amplifier 160 of this embodiment, before the laser beam reaches the output coupling mirror 370 from the cavity device CH3, the only components that reflect the laser are the convex mirror 410, the first plane mirror 430, the second plane mirror 440, and the concave mirror 420, and the laser beam is reflected four times. Therefore, according to the gas laser device 100 of this embodiment, the beam profile does not reverse due to reflection in the laser beam from the cavity device CH3 toward the convex mirror 410 and the laser beam from the concave mirror 420 toward the output coupling mirror 370.

[0184] In this embodiment, the focal line 410Lv of the virtual image 410v and the focal line 420Lv of the virtual image 420v are located on the same straight line. However, the focal lines 410Lv and 420Lv may not be located on the same straight line.

[0185] In this embodiment, the optical axis LA1 of the laser beam from the cavity device CH3 toward the convex mirror 410 and the optical axis LA2 of the laser beam from the concave mirror 420 toward the output coupling mirror 370 are on the same straight line. Therefore, for example, even without changing the design positions of the cavity device CH3 and the output coupling mirror 370, the beam expander 400 can be configured in the existing amplifier 160. Alternatively, the optical axes LA1 and LA2 may not be on the same straight line.

[0186] The above description uses the above-described embodiments as examples; however, this disclosure is not limited thereto and can be appropriately modified.

[0187] In the above embodiments, a convex mirror 410 was described as an example. This convex mirror 410 reflects the laser beam emitted from the cavity device CH3 in a manner that amplifies the beam width in the direction perpendicular to the direction in which the electrodes 332a and 332b are facing each other. However, the direction in which the beam width amplified by the convex mirror 410 is increased is not limited. For example, the direction in which the beam width amplified by the convex mirror 410 is increased could also be the direction in which the electrodes 332a and 332b are facing each other.

[0188] Furthermore, in the embodiments described above, a gas laser device 100 having a laser oscillator 130 and an amplifier 160 was used. However, the gas laser device 100 may also not have an amplifier 160. In this case, for example, a beam expander 400 is disposed between the cavity device CH1 and the output coupling mirror 70, and the laser emitted from the window 31a of the cavity device CH3 is incident on the convex mirror 410.

[0189] The foregoing description is not a limitation but merely illustrative. Therefore, those skilled in the art will understand that modifications can be made to the embodiments of this disclosure without departing from the claims. Furthermore, those skilled in the art will understand that the embodiments of this disclosure can be used in combination. Unless explicitly stated otherwise, the language used throughout this specification and the claims should be interpreted as “non-limiting”. For example, terms such as “comprising,” “having,” “possessing,” and “comprise” should be interpreted as “excluding the presence of structural elements other than the described structural elements.” Furthermore, the modifier “a” should be interpreted as meaning “at least one” or “one or more.” Moreover, the phrase “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,” and further, should be interpreted as including combinations of these and portions other than “A,” “B,” and “C.”

Claims

1. A gas laser device, comprising: a cavity device including a pair of discharge electrodes opposed to each other in an internal space in which a laser gas is enclosed, and emitting light generated from the laser gas by applying a voltage between the pair of discharge electrodes; a resonator resonating the light emitted from the cavity device between two sides across the cavity device; and a beam expander, the resonator including an output coupling mirror disposed on one side across the cavity device, transmitting a part of the light emitted from the cavity device, and reflecting another part of the light emitted from the cavity device in a manner to return to the cavity device, the beam expander being disposed between the cavity device and the output coupling mirror, the beam expander including: a holding portion; a convex mirror including a reflecting surface reflecting the light emitted from the cavity device in a manner to expand a beam width of the light, and a plurality of side surfaces, only one of which is fixed to the holding portion with an adhesive; and a concave mirror including a reflecting surface reflecting the light reflected at the convex mirror toward the output coupling mirror in a manner to collimate the light, and a plurality of side surfaces, only one of which is fixed to the holding portion with an adhesive.

2. The gas laser device according to claim 1, wherein the holding portion includes a convex mirror protrusion protruding from a surface of the one side of the convex mirror fixed with the adhesive, and located around the convex mirror, and a concave mirror protrusion protruding from a surface of the one side of the concave mirror fixed with the adhesive, and located around the concave mirror.

3. The gas laser device according to claim 2, wherein at least one of the convex mirror and the convex mirror protrusion and the concave mirror and the concave mirror protrusion are not in contact with each other.

4. The gas laser device according to claim 3, wherein at least one of the convex mirror and the concave mirror is surrounded by the corresponding one of the convex mirror protrusion and the concave mirror protrusion.

5. The gas laser device according to claim 1, wherein the holding portion includes a plate-like base member extending in a direction parallel to an optical axis of the light emitted from the cavity device toward the convex mirror; a convex mirror holder having the one side of the convex mirror fixed with the adhesive, and fixed to one main surface of the base member; and a concave mirror holder having the one side of the concave mirror fixed with the adhesive, and fixed to the one main surface of the base member.

6. The gas laser device according to claim 5, wherein at least one of the convex mirror holder and the concave mirror holder is fixed to the one main surface with the adhesive.

7. The gas laser device according to claim 6, wherein one of the convex mirror holder and the concave mirror holder is fixed to the one main surface with the adhesive, and the other is mechanically fixed to the one main surface. ​ ​ 8. The gas laser device according to claim 1, wherein the shape of the convex mirror in a case where the reflecting surface of the convex mirror is viewed from the front and the shape of the concave mirror in a case where the reflecting surface of the concave mirror is viewed from the front are rectangular.

9. The gas laser device according to claim 8, wherein the one side surface of the convex mirror extends along the length direction of the concave mirror, the one side surface of the concave mirror extends along the length direction of the concave mirror.

10. The gas laser device according to claim 1, wherein the width of the convex mirror in a direction perpendicular to the one side surface of the convex mirror and the width of the concave mirror in a direction perpendicular to the one side surface of the concave mirror are 10 mm or more and 40 mm or less.

11. The gas laser device according to claim 1, wherein the width of the convex mirror in a direction along the edge of the one side surface of the convex mirror on the reflecting surface side and the width of the concave mirror in a direction along the edge of the one side surface of the concave mirror on the reflecting surface side are 15 mm or more and 50 mm or less.

12. The gas laser device according to claim 1, wherein the beam expander further includes a plane mirror including a reflecting surface that reflects the light reflected by the convex mirror toward the concave mirror and a plurality of side surfaces, only one side surface of the plurality of side surfaces being fixed to the holding portion with an adhesive.

13. The gas laser device according to claim 12, wherein the holding portion includes: a convex mirror protrusion that protrudes from a surface that fixes the one side surface of the convex mirror with an adhesive and is located around the convex mirror; a concave mirror protrusion that protrudes from a surface that fixes the one side surface of the concave mirror with an adhesive and is located around the concave mirror; and a plane mirror protrusion that protrudes from a surface that fixes the one side surface of the plane mirror with an adhesive and is located around the plane mirror.

14. The gas laser device according to claim 13, wherein at least one of the convex mirror protrusion and the convex mirror, the concave mirror protrusion and the concave mirror, and the plane mirror protrusion and the plane mirror do not contact each other.

15. The gas laser device according to claim 13, wherein at least one of the convex mirror, the concave mirror, and the plane mirror is surrounded by the corresponding protrusion of the convex mirror protrusion, the concave mirror protrusion, and the plane mirror protrusion.

16. The gas laser device according to claim 12, wherein the optical axis of the laser light from the cavity device toward the convex mirror and the optical axis of the laser light from the concave mirror toward the output coupling mirror are located on the same straight line.

17. The gas laser device according to claim 1, wherein ​ The expander further includes a first plane mirror including a reflecting surface that reflects the light reflected by the convex mirror and a plurality of side surfaces of which only one is fixed to the holding portion with an adhesive, and a second plane mirror including a reflecting surface that reflects the light reflected by the first plane mirror toward the concave mirror and a plurality of side surfaces of which only one is fixed to the holding portion with an adhesive.

18. The gas laser device according to claim 17, wherein The holding portion includes: a convex mirror protrusion that protrudes from a surface of the one side surface of the convex mirror fixed with the adhesive and is located around the convex mirror; a concave mirror protrusion that protrudes from a surface of the one side surface of the concave mirror fixed with the adhesive and is located around the concave mirror; a first plane mirror protrusion that protrudes from a surface of the one side surface of the first plane mirror fixed with the adhesive and is located around the first plane mirror; and a second plane mirror protrusion that protrudes from a surface of the one side surface of the second plane mirror fixed with the adhesive and is located around the second plane mirror.

19. The gas laser device according to claim 1, wherein The cavity device transmits and amplifies laser light output from a laser oscillator.

20. A method for manufacturing an electronic device, comprising the steps of: generating pulsed laser light by a gas laser device, outputting the pulsed laser light to an exposure device, exposing the pulsed laser light on a photosensitive substrate in the exposure device to manufacture an electronic device, The gas laser device has: a cavity device including a pair of discharge electrodes facing each other in an internal space in which a laser gas is enclosed, and an exit through which light generated from the laser gas by applying a voltage between the pair of discharge electrodes is emitted; a resonator that resonates the light emitted from the cavity device between both sides across the cavity device; and an expander, The resonator includes an output coupling mirror disposed on one side across the cavity device, transmits a part of the light emitted from the cavity device, and reflects another part of the light emitted from the cavity device in a manner to return to the cavity device. The expander is disposed between the cavity device and the output coupling mirror. The expander includes: a holding portion; a convex mirror including a reflecting surface that reflects the light emitted from the cavity device in a manner to expand a beam width of the light, and a plurality of side surfaces of which only one is fixed to the holding portion with an adhesive; and a concave mirror including a reflecting surface that reflects the light reflected by the convex mirror toward the output coupling mirror in a manner to collimate the light, and a plurality of side surfaces of which only one is fixed to the holding portion with an adhesive. ​ ​ ​

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