Gas laser device and method for manufacturing electronic device

Abstract

A gas laser device that amplifies laser light output from a laser oscillator by means of an amplifier and emits the amplified laser light, the amplifier being provided with: a chamber device that amplifies laser light from the laser oscillator; a resonator that resonates the laser light emitted from the chamber device between both sides sandwiching the chamber device; and a beam expander, the resonator including an output coupling mirror disposed on one side sandwiching the chamber device, through which a portion of the laser beam emitted from the chamber device passes, and which reflects the other portion of the laser beam emitted from the chamber device so as to return to the chamber device, the beam expander including: a convex mirror, which is disposed on the other side of the chamber device, and which reflects the other portion of the laser beam emitted from the chamber device so as to return the other portion of the laser beam to the chamber device; a reflection mirror disposed between the chamber device and the output coupling mirror and reflecting the laser beam emitted from the chamber device so as to enlarge the beam width of the laser beam; and a concave mirror that reflects the laser beam reflected by the convex mirror toward the output coupling mirror so as to perform collimation such that the amplified beam width of the laser beam is constant.

Description

Technical Field

[0001] The present disclosure relates to a gas laser device and a method for manufacturing an electronic device. Background Art

[0002] In recent years, semiconductor exposure equipment has been required to achieve higher resolution as semiconductor integrated circuits become increasingly miniaturized and highly integrated. Consequently, there has been a trend toward shorter wavelengths of light emitted from exposure light sources. For example, gas laser devices used for exposure include KrF excimer lasers, which output laser light with a wavelength of approximately 248.0 nm, and ArF excimer lasers, which output laser light with a wavelength of approximately 193.4 nm.

[0003] The spectral line width of the natural oscillation light of the KrF excimer laser device and the ArF excimer laser device is as wide as 350pm to 400pm. Therefore, if the projection lens is composed of a material that transmits ultraviolet rays such as KrF and ArF lasers, chromatic aberration may occur. As a result, the resolution may be reduced. Therefore, it is necessary to narrow the spectral line width of the laser output from the gas laser device to a level where chromatic aberration can be ignored. Therefore, in order to narrow the spectral line width, a narrowing module (Line Narrowing Module: LNM) containing narrowing elements (interferometer, grating, etc.) is sometimes provided in the laser resonator of the gas laser device. Hereinafter, the gas laser device with a narrowed spectral line width is referred to as a narrowed gas laser device.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-233918

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 4-239784

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 4-301613 Summary of the Invention

[0009] A gas laser device according to one embodiment of the present disclosure may be a gas laser device that uses an amplifier to amplify and emit laser light output from a laser oscillator, the amplifier comprising: a chamber device through which the laser light from the laser oscillator passes, and including a pair of discharge electrodes opposed to each other in an internal space enclosing laser gas, the laser light from the laser oscillator being amplified by applying a voltage between the pair of discharge electrodes; a resonator that causes the laser light emitted from the chamber device to resonate between two sides sandwiching the chamber device; and a beam expander, the resonator including an output coupling mirror, the output coupling mirror being arranged on one side sandwiching the chamber device, transmitting a portion of the laser light emitted from the chamber device and reflecting another portion of the laser light emitted from the chamber device back to the chamber device, the beam expander being arranged between the chamber device and the output coupling mirror, the beam expander including: a convex mirror that reflects the laser light emitted from the chamber device in a manner that expands the beam width of the laser light; and a concave mirror that reflects the laser light toward the output coupling mirror in a manner that collimates the laser light reflected by the convex mirror so that the expanded beam width is constant.

[0010] A method for manufacturing an electronic device according to one embodiment of the present disclosure may be a method for manufacturing an electronic device, wherein a gas laser device generates pulsed laser light, outputs the pulsed laser light to an exposure device, and exposes the pulsed laser light on a photosensitive substrate in the exposure device in order to manufacture the electronic device, wherein the gas laser device amplifies and emits laser light output from a laser oscillator using an amplifier, the amplifier comprising: a chamber device through which the laser light from the laser oscillator passes, the amplifier comprising a pair of discharge electrodes opposed to each other in an internal space enclosed in laser gas, the laser light from the laser oscillator being amplified by applying a voltage between the pair of discharge electrodes; and a resonator for amplifying the laser light from the cavity. The laser light emitted from the chamber device resonates between the two sides of the chamber device; and a collimator, the resonator includes an output coupling mirror, the output coupling mirror is arranged on the side of the chamber device, allows a part of the laser light emitted from the chamber device to pass through, and reflects the other part of the laser light emitted from the chamber device in a manner that returns to the chamber device, the collimator is arranged between the chamber device and the output coupling mirror, the collimator includes: a convex mirror, which reflects the laser light emitted from the chamber device in a manner that expands the beam width of the laser light; and a concave mirror, which reflects the laser light toward the output coupling mirror in a manner that performs collimation so that the expanded beam width of the laser light reflected by the convex mirror is constant. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Hereinafter, several embodiments of the present disclosure will be described as simple examples with reference to the accompanying drawings.

[0012] Figure 1 It is a schematic diagram showing an example of the overall schematic configuration of an electronic device manufacturing apparatus.

[0013] Figure 2It is a schematic diagram showing an overall schematic configuration example of a gas laser device according to a comparative example.

[0014] Figure 3 This is a schematic diagram showing a schematic configuration example of an amplifier according to the first embodiment.

[0015] Figure 4 1 is a diagram showing preparations before configuring the output coupling mirror;

[0016] Figure 5 FIG. 1 is a diagram showing a configuration of an output coupling mirror;

[0017] Figure 6 This is a diagram showing how a beam expander is configured.

[0018] Figure 7 is with Figure 3 Similarly, a schematic diagram showing an example of a schematic configuration of an amplifier according to the second embodiment is shown.

[0019] Figure 8 Observed from the chamber device side Figure 7 Diagram of the beam expander shown.

[0020] Figure 9 This is a diagram showing a situation where a convex mirror and a concave mirror are arranged on a base member.

[0021] Figure 10 This is a diagram of a beam expander in a modified example of embodiment 2 as viewed from the chamber device side.

[0022] Figure 11 is with Figure 3 Similarly, a schematic diagram showing an example of a schematic configuration of an amplifier according to a third embodiment is shown.

[0023] Figure 12 This is a diagram showing a situation where an output coupling mirror, a convex mirror, and a concave mirror are arranged on a base member.

[0024] Figure 13 This is a diagram showing how a beam expander is configured.

[0025] Figure 14 is with Figure 3 Similarly, a schematic diagram showing a schematic configuration example of an amplifier in a modified example of the third embodiment is shown.

[0026] Figure 15 is with Figure 3 Similarly, a schematic diagram showing an example of a schematic configuration of an amplifier according to a fourth embodiment is shown. DETAILED DESCRIPTION

[0027] 1. Description of the electronic device manufacturing apparatus used in the exposure process of the electronic device

[0028] 2. Description of the Gas Laser Device of the Comparative Example

[0029] 2.1 Structure

[0030] 2.2 Action

[0031] 2.3 Topics

[0032] 3. Description of the Gas Laser Device of Embodiment 1

[0033] 3.1 Structure

[0034] 3.2 Action

[0035] 3.3 Function and Effect

[0036] 4. Description of the Gas Laser Device of Embodiment 2

[0037] 4.1 Structure

[0038] 4.2 Function and Effect

[0039] 5. Description of the Gas Laser Device of Embodiment 3

[0040] 5.1 Structure

[0041] 5.2 Actions and Effects

[0042] 6. Description of the Gas Laser Device of Embodiment 4

[0043] 6.1 Structure

[0044] 6.2 Actions and Effects

[0045] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and actions described in each embodiment are not necessarily required as the structures and actions of the present disclosure. In addition, the same reference numerals are given to the same structural elements, and repeated descriptions are omitted.

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

[0047] Figure 1 Schematic diagram showing an overall schematic configuration example of an electronic device manufacturing apparatus used in an exposure process of an electronic device. Figure 1As 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 optical system 210 having a plurality of mirrors 211, 212, and 213, and a projection optical system 220. The illumination optical system 210 illuminates the mask pattern on the mask stage RT using the laser light incident from the gas laser device 100. The projection optical system 220 performs a reduced projection of the laser light transmitted through the mask so as to form an image on a workpiece (not shown) arranged on the work stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a photoresist. The exposure device 200 exposes the workpiece to the laser light reflecting the mask pattern by moving the mask stage RT and the work stage WT in parallel in synchronization. By transferring the device pattern to the semiconductor wafer using the above-mentioned exposure process, a semiconductor device as an electronic device can be manufactured.

[0048] 2. Description of the Gas Laser Device of the Comparative Example

[0049] 2.1 Structure

[0050] A gas laser device of a comparative example will be described. Note that the comparative examples disclosed herein are known only to the applicant and are not publicly known examples recognized by the applicant.

[0051] Figure 2 : This is a schematic diagram showing an example of the overall schematic structure of the gas laser device 100 of this example. The gas laser device 100 is, for example, an ArF excimer laser device that uses a mixed gas containing argon (Ar), fluorine (F2), and neon (Ne). The gas laser device 100 outputs laser light having a central wavelength of approximately 193.4 nm. Furthermore, the gas laser device 100 may be a gas laser device other than the ArF excimer laser device, for example, a KrF excimer laser device that uses a mixed gas containing krypton (Kr), F2, and Ne. In this case, the gas laser device 100 emits laser light having a central wavelength of approximately 248.0 nm. A mixed gas containing Ar, F2, and Ne as a laser medium, or a mixed gas containing Kr, F2, and Ne as a laser medium, is sometimes referred to as a laser gas. Furthermore, helium (He) may be used in place of Ne in the mixed gases used in the ArF excimer laser device and the KrF excimer laser device, respectively.

[0052] The gas laser device 100 of this example includes a shell 110, a laser oscillator 130 as a master oscillator arranged in the internal space of the shell 110, an optical transmission unit 141, an amplifier 160 as a 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 as main structures.

[0053] The laser oscillator 130 includes a chamber device CH1 , a charger 41 , a pulse power module 43 , a band-narrowing module 60 , and an output coupling mirror 70 as main components.

[0054] exist Figure 2 , the internal structure of chamber device CH1 as viewed from a direction substantially perpendicular to the direction of laser light propagation is shown. Chamber device CH1 includes a housing 30, a pair of windows 31a, 31b, a pair of electrodes 32a, 32b, an insulating portion 33, a feedthrough 34, and an electrode holder 36 as its main components.

[0055] The laser gas is supplied from the laser gas supply device 703 via piping to the interior of the housing 30, enclosing the laser gas therein. The laser medium in the laser gas excites the laser gas, generating light within the interior space. This light travels toward the windows 31a and 31b.

[0056] Window 31a is located on the front wall of housing 30 in the direction of laser light traveling from gas laser device 100 to exposure device 200, while window 31b is located on the rear wall of housing 30 in the same direction of laser light traveling. Windows 31a and 31b are tilted to form a Brewster's angle with respect to the direction of laser light traveling to suppress reflection of P-polarized laser light. The emission surfaces of windows 31a and 31b are flat.

[0057] Electrodes 32a and 32b are arranged facing each other within the interior of housing 30, with their longitudinal sides aligned with the direction of light travel generated by the high voltage applied between electrodes 32a and 32b. The space between electrodes 32a and 32b in housing 30 is bounded by windows 31a and 31b. Electrodes 32a and 32b serve as discharge electrodes for exciting the laser medium through glow discharge. In this example, electrode 32a serves as the cathode, and electrode 32b serves as the anode.

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

[0059] The charger 41 is a DC power supply device that charges a capacitor (not shown) located inside the pulse power module 43 at a specified voltage. The charger 41 is located outside the housing 30 and is connected to the pulse power module 43. The pulse power module 43 includes a switch (not shown) controlled by the processor 190. The pulse power module 43 is a voltage application circuit that, when the switch is switched from off to on under the control described above, boosts the voltage applied from the charger 41 to generate a pulsed high voltage, and applies this high voltage to the electrodes 32a and 32b. When the high voltage is applied, a discharge occurs between the electrodes 32a and 32b. The energy of this discharge excites the laser medium within the housing 30. When the excited laser gas transitions to the ground state, light is emitted, which is then emitted through the windows 31a and 31b and emitted to the outside of the housing 30.

[0060] The narrowband module 60 includes a housing 65, a prism 61, a grating 63, and a rotating stage (not shown) disposed in the interior of the housing 65. The housing 65 has an opening, and the housing 65 is connected to the rear side of the housing 30 via the opening.

[0061] The prism 61 expands the beam width of the light emitted from the window 31b and causes the light to be incident on the grating 63. In addition, the prism 61 reduces the beam width of the reflected light from the grating 63 and causes the light to return to the internal space of the housing 30 via the window 31b. The prism 61 is supported on a rotating table and rotated by the rotating table. The incident angle of the light relative to the grating 63 is changed by the rotation of the prism 61. Therefore, by rotating the prism 61, the wavelength of the light returned from the grating 63 via the prism 61 to the housing 30 can be selected. Figure 2 , an example in which one prism 61 is arranged is shown, but two or more prisms may be arranged.

[0062] The surface of the grating 63 is made of a high-reflectivity material and has multiple grooves spaced at regular intervals. The grating 63 is a dispersive optical element. The cross-sectional shape of each groove is, for example, a right triangle. Light incident on the grating 63 from the prism 61 is reflected by these grooves and diffracted in a direction corresponding to the wavelength of the light. The grating 63 is configured in a Littrow configuration so that the angle of incidence of light incident on the grating 63 from the prism 61 matches the diffraction angle of diffracted light of the desired wavelength. As a result, light of the desired wavelength is returned to the housing 30 via the prism 61.

[0063] The output coupling mirror 70 faces the window 31a, transmits part of the laser light emitted from the window 31a, and reflects the other part to return to the interior of the housing 30 through the window 31a. The output coupling mirror 70 is fixed to a holder (not shown) and is arranged in the interior of the housing 110.

[0064] The grating 63 and the output coupling mirror 70 disposed across the housing 30 form a Fabry-Perot resonator. The housing 30 is disposed on the optical path of the resonator. Therefore, the resonator resonates light between both sides of the cavity device CH1.

[0065] The optical transmission unit 141 includes high-reflection mirrors 141b and 141c as its main structure. The high-reflection mirrors 141b and 141c are fixed to holders (not shown) with their respective tilt angles adjusted, and are located within the interior space of the housing 110. The high-reflection mirrors 141b and 141c reflect laser light with a high degree of reflection. The high-reflection mirrors 141b and 141c are located on the optical path of the laser light from the output coupling mirror 70. The laser light is reflected by the high-reflection mirrors 141b and 141c and travels toward the rear mirror 371 of the amplifier 160. At least a portion of the laser light is transmitted through the rear mirror 371.

[0066] Amplifier 160 amplifies the energy of the laser light output from laser oscillator 130. The basic structure of amplifier 160 is substantially the same as that of laser oscillator 130. To distinguish the components of amplifier 160 from those of laser oscillator 130, the chamber device, housing, pair of windows, pair of electrodes, insulating portion, feedthrough, electrode holder, charger, pulse power module, and output coupling mirror of amplifier 160 are described as chamber device CH3, housing 330, pair of windows 331a and 331b, pair of electrodes 332a and 332b, insulating portion 333, feedthrough 334, electrode holder 336, charger 341, pulse power module 343, and output coupling mirror 370. Electrodes 332a and 332b generate discharge to amplify the laser light from laser oscillator 130. Pulse power module 343, like pulse power module 43, is a voltage application circuit.

[0067] The amplifier 160 differs from the laser oscillator 130 mainly in that the amplifier 160 does not include the bandwidth narrowing module 60 but includes a rear mirror 371 and a beam expander 400 .

[0068] The rear mirror 371 is disposed between the high-reflection mirror 141c and the window 331b, facing each of them. The rear mirror 371 transmits a portion of the laser light from the laser oscillator 130 toward the space between the electrodes 332a and 332b, and reflects a portion of the laser light amplified by the electrodes 332a and 332b toward the space between the electrodes 332a and 332b.

[0069] The output coupling mirror 370 is arranged at a position closer to the side of the chamber device CH3 than to the side opposite to the rear mirror 371, and the beam expander 400 is arranged between the chamber device CH3 and the output coupling mirror 370. The beam expander 400 of this example includes two prisms 401 and 402. The prism 401 expands the beam width of the laser light emitted from the chamber device CH3. The prism 402 further expands the beam width of the light whose beam width has been expanded by the prism 401 and emits the light toward the output coupling mirror 370. In addition, the prism 402 reduces the beam width of the reflected light from the output coupling mirror 370, and the prism 401 further reduces the beam width of the light whose beam width has been reduced by the prism 402 and returns the light to the internal space of the housing 330 through the window 331a. The direction in which the prisms 401 and 402 expand or reduce the beam width is the direction in which the electrodes 332a and 332b are opposed to each other and the direction perpendicular to the optical axis of the light.

[0070] A partially reflective film having a predetermined reflectivity is applied to the surface of the output coupling mirror 370 facing the beam expander 400. The output coupling mirror 370 reflects a portion of the laser light from the chamber device CH3, whose beam width has been expanded by the beam expander 400, toward the beam expander 400, while transmitting the remaining portion of the laser light.

[0071] The output coupling mirror 370 may be circular. The surface of the output coupling mirror 370 facing the beam expander 400 and the surface opposite thereto may also be flat surfaces. The rear mirror 371 and the output coupling mirror 70 have similar structures to the output coupling mirror 370.

[0072] A resonator is formed by a rear mirror 371 and an output coupling mirror 370, which are arranged between the housing 330, to resonate the laser light amplified by the electrodes 332a and 332b. The housing 330 and the beam expander 400 are arranged on the optical path of the resonator. The laser light emitted from the window 331a of the housing 330 is incident on the output coupling mirror 370 via the beam expander 400 and is reflected by the output coupling mirror 370. The laser light reflected by the output coupling mirror 370 returns to the interior space of the housing 330 via the beam expander 400 and the window 331b, and is emitted from the window 331a. The laser light emitted from the window 331a is reflected by the rear mirror 371 and returns to the interior space of the housing 330 via the window 331b. In this way, the laser light emitted from the housing 330 reciprocates between the rear mirror 371 and the output coupling mirror 370. The reciprocating laser light is amplified each time it passes through the laser gain space between the electrodes 332a and 332b. That is, the resonator resonates light between both sides of the chamber device CH3, and the output coupling mirror 370 is arranged on one side of the chamber device CH3. A portion of the amplified laser light passes through the output coupling mirror 370. The laser light that passes through the output coupling mirror 370 travels toward the detection unit 153.

[0073] The detection section 153 includes a beam splitter 153 b and a photosensor 153 c as main structures.

[0074] The beam splitter 153b is disposed on the optical path of the laser beam transmitted through the output coupling mirror 370. The beam splitter 153b transmits the laser beam transmitted through the output coupling mirror 370 through the output window 173 with high transmittance and reflects a portion of the laser beam toward the light receiving surface of the optical sensor 153c.

[0075] Optical sensor 153c measures the pulse energy of the 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 32a and 32b of amplifier 160 based on this signal.

[0076] An exit window 173 is provided on the side of the detector 153 opposite the output coupling mirror 370 relative to the beam splitter 153b. 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 having a central wavelength of 193.4 nm.

[0077] The display unit 180 is a monitor that displays the control state of the processor 190 based on a signal from the processor 190. The display unit 180 may be arranged outside the housing 110.

[0078] The processor 190 of the present disclosure is a processing device comprising a storage device that stores a control program and a CPU (Central Processing Unit) that executes the control program. Processor 190 is specifically configured or programmed to perform the various processes included in the present disclosure. Furthermore, processor 190 controls the entire gas laser device 100. Furthermore, processor 190 is electrically connected to an exposure processor (not shown) of exposure device 200, transmitting and receiving various signals to and from the exposure processor.

[0079] The laser gas exhaust device 701 and the laser gas supply device 703 are electrically connected to the processor 190. The laser gas exhaust device 701 includes an exhaust pump (not shown). In response to a control signal from the processor 190, the laser gas is exhausted from the interior of the housing 30 or 330 through the piping by suction from the exhaust pump. The laser gas supply device 703 supplies laser gas from a laser gas supply source (not shown) located outside the housing 110 into the interior of the housing 30 or 330 through the piping in response to a control signal from the processor 190.

[0080] 2.2 Action

[0081] Next, the operation of the gas laser device 100 according to the comparative example will be described.

[0082] Before the gas laser device 100 emits laser light, laser gas is supplied from the laser gas supply device 703 to the internal space of the housings 30 , 330 .

[0083] When the gas laser device 100 emits laser light, the processor 190 receives a signal indicating target energy Et and a light emission trigger signal from an exposure processor (not shown) of the exposure device 200. Target energy Et is the target value of the energy of the laser light used in the exposure process. The processor 190 sets a predetermined charging voltage for the charger 41 so that the energy E reaches the target energy Et, and turns on the switch of the pulse power module 43 in synchronization with the light emission trigger signal. As a result, the pulse power module 43 generates a pulsed high voltage based on the electrical energy stored in the charger 41, and applies the high voltage 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. When the laser medium returns to the ground state, light is emitted. 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 within the internal space of the housing 30, causing laser oscillation. Part of the laser light passes through the output coupling mirror 70 , is reflected by the high reflection mirrors 141 b and 141 c , passes through the rear mirror 371 and the window 31 b , and travels into the housing 330 .

[0084] Processor 190 turns on the switch of pulse power module 343 to generate a discharge when the laser light from laser oscillator 130 travels into the discharge space within housing 330. Specifically, processor 190 controls pulse power module 343 so that a high voltage is applied to electrodes 332a and 332b after a predetermined delay time has elapsed from the timing of turning on the switch of pulse power module 343.

[0085] Thus, the laser light incident on the amplifier 160 is amplified in the amplifier 160. In addition, as described above, the laser light that has entered the internal space of the housing 330 travels to the output coupling mirror 370 via the window 331a and the beam expander 400 and is reflected by the output coupling mirror 370. The laser light reflected by the output coupling mirror 370 travels to the internal space of the housing 330 via the beam expander 400 and the window 331a and is emitted from the window 331b. The light emitted from the window 331b is reflected by the rear mirror 371 and travels toward the internal space of the housing 330 via the window 331b. In this way, the laser light of a specified wavelength reciprocates between the rear mirror 371 and the output coupling mirror 370. Each time the laser light passes through the discharge space inside the housing 330, it is amplified, and a portion of the laser light becomes the amplified laser light.

[0086] In addition, the amplified laser light from the amplifier 160 passes through the output coupling mirror 370 and travels toward the beam splitter 153 b .

[0087] Part of the amplified laser light that has reached the beam splitter 153 b passes through the beam splitter 153 b and the exit window 173 and travels toward the exposure device 200 , while the other part is reflected by the beam splitter 153 b and travels toward the optical sensor 153 c .

[0088] Optical sensor 153c measures the energy E of the received amplified laser light. Optical sensor 153c outputs a signal representing the measured energy E to processor 190. Processor 190 performs feedback control on the charging voltage of chargers 41 and 341 to ensure that the difference ΔE between the energy E and the target energy Et falls within an acceptable range. Laser light with a difference ΔE within the acceptable range passes through beam splitter 153b and exit window 173 and enters exposure device 200.

[0089] 2.3 Topics

[0090] In the comparative example, the beam expander 400 expands the beam width of the laser light emitted from the chamber device CH3 using two prisms 401 and 402, and then emits the light toward the output coupling mirror 370. This reduces the energy density of the laser light incident on the output coupling mirror 370, thereby suppressing the degradation of the output coupling mirror 370 over time. However, since the prisms 401 and 402 are transmissive optical elements, there is a concern that the prisms 401 and 402 may degrade over time due to the transmitted light.

[0091] Therefore, in the following embodiments, a gas laser device capable of suppressing temporal degradation is exemplified.

[0092] 3. Description of the Gas Laser Device of Embodiment 1

[0093] Next, the gas laser device 100 according to Embodiment 1 will be described. The same components as those described above are denoted by the same reference numerals, and duplicate descriptions will be omitted unless otherwise specified. In some drawings, some components are omitted or simplified for easier viewing.

[0094] 3.1 Structure

[0095] Figure 3 1 is a schematic diagram showing an example of the schematic configuration of the amplifier 160 according to the first embodiment, and is a schematic diagram of the amplifier 160 viewed from a direction in which a pair of electrodes 332a and 332b face each other. Figure 3 The internal structure of the chamber device CH3 is shown in FIG.

[0096] The main difference between the amplifier 160 of this embodiment and the amplifier 160 of the comparative example is that the beam expander 400 includes a convex mirror 411 and a concave mirror 412 .

[0097] Convex mirror 411 includes a reflective surface 411s for reflecting light and is fixed to a holder (not shown) so as to reflect the light toward concave mirror 412. Concave mirror 412 includes a reflective surface 412s for reflecting light and is fixed to a holder (not shown) so as to reflect the light toward output coupling mirror 370. Convex mirror 411 reflects laser light from chamber device CH3 toward concave mirror 412, and concave mirror 412 reflects laser light from convex mirror 411 toward output coupling mirror 370. Furthermore, concave mirror 412 reflects laser light reflected by output coupling mirror 370 toward convex mirror 411, and convex mirror 411 reflects light reflected by concave mirror 412 toward chamber device CH3. This light then returns to the interior of housing 330 through window 331a.

[0098] In this embodiment, the convex mirror 411 and the concave mirror 412 are columnar components extending in the direction in which the electrodes 332a and 332b oppose each other. The cross-sectional shape of the reflecting surface 411s in the convex mirror 411, perpendicular to the direction in which the electrodes 332a and 332b oppose each other, is a parabola. The cross-sectional shape of the reflecting surface 411s in the direction in which the electrodes 332a and 332b oppose each other, is a straight line. Furthermore, the cross-sectional shape of the reflecting surface 412s in the concave mirror 412, perpendicular to the direction in which the electrodes 332a and 332b oppose each other, is a parabola. The cross-sectional shape of the reflecting surface 412s in the direction in which the electrodes 332a and 332b oppose each other, is a straight line. Furthermore, the focal position of the reflecting surface 411s roughly overlaps with the focal position of the reflecting surface 412s. In other words, the positions of the convex mirror 411 and the concave mirror 412 are adjusted in this manner.

[0099] In the present specification and claims, perpendicularity refers to a state where the angle formed is 85 degrees or more and 95 degrees or less, and parallelism refers to a state where the angle formed is within 5 degrees.

[0100] In this embodiment, the output coupling mirror 370 is a rectangular shape that is long in a direction perpendicular to the direction in which the electrodes 332a and 332b face each other. Furthermore, the output coupling mirror 370 extends from the incident position of the laser beam reflected by the concave mirror 412 to a position intersecting the optical axis LA of the laser beam directed from the chamber device CH3 toward the convex mirror 411. Therefore, when the convex mirror 411 is not provided, the laser beam from the chamber device CH3 is incident on the output coupling mirror 370. The shape of the output coupling mirror 370 is not limited and, for example, may be circular.

[0101] 3.2 Action

[0102] When laser light is emitted from window 331a of housing 330, it is reflected by convex mirror 411 toward concave mirror 412. The cross-sectional shape of reflective surface 411s in convex mirror 411, perpendicular to the direction in which electrodes 332a and 332b oppose each other, is a parabola. Therefore, the beam width of the laser light reflected by convex mirror 411 is expanded in the direction perpendicular to the direction in which electrodes 332a and 332b oppose each other and to the optical axis LA of the laser light. This laser light, with its beam width expanded, is reflected by concave mirror 412 toward output coupling mirror 370. The cross-sectional shape of reflective surface 412s in concave mirror 412, perpendicular to the direction in which electrodes 332a and 332b oppose each other, is a parabola. The focal position of reflective surface 411s and the focal position of reflective surface 412s approximately overlap. Therefore, the laser light reflected by concave mirror 412 is collimated to a constant beam width and then enters output coupling mirror 370.

[0103] The laser light reflected by the output coupling mirror 370 is reflected by the concave mirror 412 toward the convex mirror 411. The beam width of this laser light is reduced in a direction perpendicular to the direction in which the electrodes 332a and 332b face each other. This laser light with a reduced beam width is reflected by the convex mirror 411 toward the window 331a. This laser light is collimated so that the amplified beam width remains constant and returns to the interior of the housing 330 through the window 331a.

[0104] 3.3 Function and Effect

[0105] The beam expander 400 of this embodiment includes a convex mirror 411 and a concave mirror 412. The convex mirror 411 reflects the laser light from the chamber device CH3 in a manner that expands the beam width of the laser light. The concave mirror 412 reflects the laser light toward the output coupling mirror 370 in a manner that collimates the laser light reflected by the convex mirror 411 so that the amplified beam width of the laser light remains constant. Generally speaking, optical elements that reflect light tend to be less susceptible to aging than optical elements that transmit light. Therefore, according to the gas laser device 100 of this embodiment, compared with a case where the beam expander 400 is composed of the prisms 401 and 402 that transmit light, it is possible to suppress the aging of the beam expander 400. As a result, it is possible to suppress the aging of the gas laser device 100.

[0106] In this embodiment, the cross-sectional shapes of the reflecting surfaces 411s and 412s perpendicular to the direction in which the electrodes 332a and 332b face each other are parabolic, but this is not a limitation. These cross-sectional shapes may also be arcs, for example. In this case, the convex mirror 411 and the concave mirror 412 are arranged so that the focal position of the reflecting surface 411s overlaps the focal position of the reflecting surface 412s.

[0107] In this embodiment, the convex mirror 411 reflects the laser light emitted from the chamber device CH3 so as to expand the beam width in the direction opposite the electrodes 332a and 332b and perpendicular to the laser light's optical axis LA. However, the direction in which the beam width is expanded by the convex mirror 411 is not limited to this. The beam width can be expanded in multiple directions, or the beam diameter can be expanded. In this case, for example, the reflecting surfaces 411s and 412s are portions of a parabola of revolution or a sphere.

[0108] In this embodiment, as described above, the output coupling mirror 370 extends from the incident position of the laser beam reflected by the concave mirror 412 to the position intersecting the optical axis LA. Therefore, the output coupling mirror 370 and the beam expander 400 can be arranged as follows, for example.

[0109] Figure 4 3 is a diagram showing the preparations before configuring the output coupling mirror 370. Figure 5 3 is a diagram showing the configuration of the output coupling mirror 370. Figure 6 It is a diagram showing how the beam expander 400 is arranged.

[0110] like Figure 4 As shown, first, in a state where the chamber device CH3 is not installed, light is emitted from the autocollimator 450 toward the rear mirror 371. The autocollimator 450 measures the angle between the optical axis of the light emitted from the autocollimator 450 and the optical axis of the light reflected by the rear mirror 371 and incident on the autocollimator 450. The orientation of the autocollimator 450 relative to the rear mirror 371 is adjusted so that the angle becomes zero degrees.

[0111] Then, if Figure 5 As shown, the output coupling mirror 370 is positioned at the designed position, and light is emitted from the autocollimator 450. The autocollimator 450 measures the angle between the optical axis of the light emitted from the autocollimator 450 and the optical axis of the light reflected by the output coupling mirror 370 and incident on the autocollimator 450. The orientation of the output coupling mirror 370 relative to the rear mirror 371 is adjusted so that this angle is zero degrees. As described above, the output coupling mirror 370 extends to a position intersecting the optical axis LA. Therefore, the output coupling mirror 370 can be correctly oriented relative to the rear mirror 371 without moving the autocollimator 450.

[0112] Then, if Figure 6As shown, the beam expander 400 is positioned in the designed position. The autocollimator 450 is moved to a position where the light emitted from the autocollimator 450 and returned from the concave mirror 412 is incident on the autocollimator 450. The autocollimator 450 measures the angle between the optical axis of the light emitted from the autocollimator 450 and the optical axis of the light reflected from the output coupler 370 and incident on the autocollimator 450. The orientation of the autocollimator 450 relative to the rear mirror 371 is adjusted so that this angle is zero degrees. The autocollimator 450 then measures the angle between the optical axis of the light emitted from the autocollimator 450 and the optical axis of the light returned from the concave mirror 412 to the autocollimator 450. The positions of the convex mirror 411 and the concave mirror 412, as well as their orientation relative to the output coupler 370, are adjusted so that this angle is zero degrees. In this way, the output coupler 370, the convex mirror 411, and the concave mirror 412 can be arranged.

[0113] 4. Description of the Gas Laser Device of Embodiment 2

[0114] Next, the gas laser device 100 according to Embodiment 2 will be described. The same reference numerals are used for the same components as those described above, and duplicate descriptions will be omitted unless otherwise specified. In some drawings, some components are omitted or simplified for easier viewing.

[0115] 4.1 Structure

[0116] Figure 7 is with Figure 3 Similarly, a schematic diagram showing an example of the schematic configuration of the amplifier 160 according to this embodiment is shown. Figure 8 Viewed from the chamber device CH3 side Figure 7 Diagram of the beam expander 400 shown.

[0117] The main difference between the amplifier 160 of this embodiment and the amplifier 160 of the first embodiment is that the beam expander 400 further includes a base member 413 and a drive mechanism 430. Figure 7 、 Figure 8 , a state in which a slit member 420 described later is arranged on the base member 413 is shown. However, when the laser beam is emitted from the gas laser device 100 , the slit member 420 is removed.

[0118] The base member 413 in this embodiment is a plate-shaped member extending parallel to the optical axis LA of the laser beam directed from the chamber device CH3 toward the convex mirror 411. In this embodiment, the base member 413 extends perpendicular to the direction in which the electrodes 332a and 332b face each other, but this is not limiting. The convex mirror 411 and the concave mirror 412 are arranged on one main surface of the base member 413. Furthermore, the base member 413 is provided with a pair of positioning portions 425 that can position the slit member 420 at a predetermined position.

[0119] The slit component 420 includes a main body 421 and a retaining portion 422. The main body 421 is a plate-shaped component provided with a slit 421h serving as a through hole. The main body 421 is circular, and the slit 421h is a rectangular shape that is longer in the direction in which the electrodes 332a and 332b are opposite to each other. The retaining portion 422 is a plate-shaped component provided with a through hole 422h in which the main body 421 can be embedded. By embedding the main body 421 in the through hole 422h, the main body 421 is retained in the retaining portion 422. Therefore, it can be understood that the slit component 420 is provided with the slit 421h. In addition, the main body 421 and the retaining portion 422 may be formed as a whole, or the slit 421h may be provided in the retaining portion 422.

[0120] The pair of positioning parts 425 of this embodiment are columnar parts with a roughly L-shaped cross-section. The pair of positioning parts 425 can hold the slit part 420 by clamping the holding part 422 of the slit part 420 from a direction perpendicular to the thickness direction. In addition, the positioning part 425 can abut against one main surface of the holding part 422. By making the positioning part 425 abut against one main surface of the holding part 422, the side surface of the base part 413 side of the holding part 422 abuts against the main surface of the base part 413, thereby positioning the slit part 420 at a predetermined position. The predetermined position is a position closer to the chamber device CH3 side than the convex mirror 411 of the base part 413. When the slit part 420 is arranged at this predetermined position, it is a position where the optical axis LA passes through the slit 421h.

[0121] The drive mechanism 430 of this embodiment includes a rotating mechanism capable of rotating the base member 413 about an axis 430c perpendicular to the direction in which the base member 413 extends, and a moving mechanism capable of moving the base member 413 in a direction parallel to the direction in which the base member 413 extends. In the drive mechanism 430 of this embodiment, the rotating mechanism is mounted on the moving mechanism, and the base member 413 is mounted on the rotating mechanism. The axis 430c overlaps with the center of gravity of the base member 413, but the position of the axis 430c is not limited to this.

[0122] 4.2 Function and Effect

[0123] The beam expander 400 of this embodiment includes a plate-shaped base member 413 extending parallel to the optical axis LA and having a convex mirror 411 and a concave mirror 412 disposed on its principal surface. Therefore, by arranging the base member 413 in the designed position, the convex mirror 411 and the concave mirror 412 can be positioned in the designed position. This makes it easier to position the convex mirror 411 and the concave mirror 412 in the designed position than when the convex mirror 411 and the concave mirror 412 are disposed separately.

[0124] Furthermore, in this embodiment, the base member 413 is provided with a positioning portion 425. When the slit member 420 having the slit 421h is positioned at a predetermined position, the positioning portion 425 can position the slit member 420 at the predetermined position. The predetermined position is located closer to the chamber device CH3 than the convex mirror 411 of the base member 413. When the slit member 420 is positioned at the predetermined position, the optical axis LA passes through the slit 421h. Therefore, for example, the beam expander 400 can be configured as follows.

[0125] Figure 9 This is a diagram showing a situation where a convex mirror 411 and a concave mirror 412 are arranged on a base member 413.

[0126] First, if Figure 9 As shown, the slit member 420 is positioned in the base member 413 at a position positioned by the positioning portion 425, and the convex mirror 411 and the concave mirror 412 are positioned at the designed positions. The adjustment light source 452 irradiates the slit member 420 with parallel light having a propagation direction perpendicular to the slit member 420. The entire slit 421h is located within the irradiation point of the light in the slit member 420. Therefore, parallel light having a shape roughly the same as that of the slit 421h is reflected by the convex mirror 411. The light reflected by the convex mirror 411 and then by the concave mirror 412 is measured using a beam measuring device 453. Examples of the beam measuring device 453 include an optical position sensor, a spectrometer, a beam profiler, and a wavefront sensor. The beam measuring device 453 measures the incident position of the light from the concave mirror 412, as well as the beam size and divergence angle of the light. The beam size is the size of the light reflected and collimated by the concave mirror 412, and the divergence angle indicates the degree of collimation of the light after reflection from the concave mirror 412. Based on the measurement results, the positions of convex mirror 411 and concave mirror 412 and their orientation relative to slit member 420 are adjusted so that the incident position of light from concave mirror 412 on beam measurement device 453 is at a predetermined position, the beam size is a predetermined size, and the divergence angle is within a predetermined range. Next, base member 413, on which convex mirror 411 and concave mirror 412 are mounted, is mounted on drive mechanism 430.

[0127] Next, without arranging the chamber device CH3, the output coupling mirror 370 is arranged at the designed position. Figure 4 and Figure 5 In the same manner as in the embodiment 1 shown, the orientation of the output coupling mirror 370 relative to the rear mirror 371 is adjusted. Next, the beam expander 400 with the convex mirror 411 and the concave mirror 412 adjusted is placed at the designed position. Figure 6 As in the case of the first embodiment shown, the autocollimator 450 measures the angle between the optical axis of the light emitted from the autocollimator 450 and the optical axis of the light returning to the autocollimator 450 from the concave mirror 412. The drive mechanism 430 adjusts the position and orientation of the base member 413 relative to the rear mirror 371 so that this angle is zero degrees. In this way, the beam expander 400 can be configured. Alternatively, the position and orientation of the base member 413 may not be adjusted, and the beam expander 400 may not include the drive mechanism 430. For example, securing working space may make it difficult to adjust the position and orientation of the convex mirror 411 and the concave mirror 412 disposed in the gas laser device 100. However, in this embodiment, the beam expander 400 can be configured with the relative position and orientation of the convex mirror 411 and the concave mirror 412 adjusted. Therefore, compared to a case where the beam expander 400 does not include the base member 413 , the positions and orientations of the convex mirror 411 and the concave mirror 412 can be easily adjusted to the correct positions and orientations.

[0128] In addition, in this embodiment, the slit member 420 is positioned at a predetermined position by a pair of positioning portions 425, but the positioning portion for positioning the slit member 420 at a predetermined position is not limited thereto. For example, the positioning portion may be an annular member that inserts a portion of the slit member 420 into the internal space to hold the slit member 420.

[0129] In the present embodiment, the base member 413 is provided with the positioning portion 425 , but the base member 413 may not be provided with the positioning portion 425 .

[0130] The slit 421h of the slit member 420 of this embodiment is rectangular, but the present invention is not limited thereto. Other examples of the slit 421h will be described using the following modified examples.

[0131] Figure 10 This is a diagram showing the beam expander 400 in a modified example of the second embodiment as viewed from the chamber device CH3 side. Figure 10 , the slit member 420 is shown to be arranged on the base member 413 . However, when the laser beam is emitted from the gas laser device 100 , the slit member 420 is removed.

[0132] The main difference between the slit part 420 of this modification and the slit part 420 of embodiment 2 is that the slit 421h is circular. When the slit part 420 is arranged at a predetermined position that can be positioned by a pair of positioning parts 425, the optical axis LA of the laser light from the chamber device CH3 toward the convex mirror 411 passes through the slit 421h. Even in the slit part 420 of this modification, the convex mirror 411 and the concave mirror 412 can be arranged on the base part 413 in the same manner as in embodiment 2. In addition, the slit 421h is not limited to this. The slit 421h can be the same shape as the outer shape of the laser light emitted from the chamber device CH3, and the size of the laser light can be the same as the size of the slit 421h. In addition, the slit 421h can also be an elliptical shape that forms a circular beam in the beam measuring device 453.

[0133] 5. Description of the Gas Laser Device of Embodiment 3

[0134] Next, a gas laser device 100 according to Embodiment 3 will be described. The same reference numerals are used for components identical to those described above, and duplicate descriptions will be omitted unless otherwise specified. Furthermore, in some drawings, some components are omitted or simplified for easier viewing.

[0135] 5.1 Structure

[0136] Figure 11 is with Figure 3 Similarly, a schematic diagram showing an example of the schematic configuration of the amplifier 160 of this embodiment is shown. The main difference between the amplifier 160 of this embodiment and the amplifier 160 of the second embodiment is that the output coupling mirror 370 is arranged on the base member 413. Figure 11 , the slit member 420 is shown to be arranged on the base member 413 . However, when the laser beam is emitted from the gas laser device 100 , the slit member 420 is removed.

[0137] The output coupling mirror 370 of this embodiment is disposed on the main surface of the base member 413. However, the output coupling mirror 370 may also be disposed on, for example, a side surface of the base member 413 that is opposite to the output coupling mirror 370 side. In this case, the side surface of the base member 413 faces the rear mirror 371 side surface of the output coupling mirror 370. Furthermore, the output coupling mirror 370 does not extend to a position intersecting the optical axis LA, but may extend to a position intersecting the optical axis LA.

[0138] 5.2 Actions and Effects

[0139] The beam expander 400 of this embodiment includes a drive mechanism 430, and an output coupling mirror 370, a convex mirror 411, and a concave mirror 412 are arranged on a base member 413. Therefore, the beam expander 400 can be arranged, for example, as follows.

[0140] Figure 12 4 is a diagram showing a configuration of an output coupling mirror 370, a convex mirror 411, and a concave mirror 412 on a base member 413. Figure 13 It is a diagram showing how the beam expander 400 is arranged.

[0141] First, if Figure 12 As shown, the slit component 420 is arranged at a position positioned by the positioning portion 425 in the base component 413, and the output coupling mirror 370, the convex mirror 411 and the concave mirror 412 are arranged at the designed positions. The orientation of the output coupling mirror 370 is adjusted so that the slit component 420 is parallel to the output coupling mirror 370. Next, parallel light with a propagation direction perpendicular to the slit component 420 is irradiated from the adjustment light source 452 to the slit component 420. The entire slit 421h is located within the irradiation point of the light in the slit component 420. Therefore, the parallel light with an appearance roughly the same as that of the slit 421h is reflected by the convex mirror 411. The light reflected by the convex mirror 411 and then reflected by the concave mirror 412 is measured by the light beam measuring device 453. The incident position of the light from the concave mirror 412, the beam size of the light and the divergence angle are measured by the light beam measuring device 453. Based on the measurement results, the positions of convex mirror 411 and concave mirror 412 and their orientation relative to slit member 420 are adjusted so that the incident position of light from concave mirror 412 on beam measurement device 453 is at a predetermined position, the beam size is a predetermined size, and the divergence angle is within a predetermined range. Next, base member 413, on which convex mirror 411 and concave mirror 412 are mounted, is mounted on drive mechanism 430.

[0142] Then, if Figure 13As shown, without the chamber device CH3, the beam expander 400 is positioned in its designed position. An autocollimator 450 is placed on the side of the rear mirror 371 opposite the beam expander 400, so that the emitted light enters the slit 421h via the rear mirror 371. The autocollimator 450 measures the angle between the optical axis of the light emitted from the autocollimator 450 and the optical axis of the light reflected by the rear mirror 371 and entering the autocollimator 450. The orientation of the autocollimator 450 is adjusted so that this angle is zero and the light transmitted through the rear mirror 371 enters the slit 421h. Next, the autocollimator 450 measures the angle between the optical axis of the light emitted from the autocollimator 450 and the optical axis of the light returning from the beam expander 400 to the autocollimator 450. The drive mechanism 430 adjusts the position of the base member 413 and its rotation angle around the axis 430c so that this angle is zero. In this manner, the output coupling mirror 370 and the beam expander 400 can be arranged. Furthermore, according to the gas laser device 100 of this embodiment, even without providing drive mechanisms for individually adjusting the orientations and positions of the output coupling mirror 370, the convex mirror 411, and the concave mirror 412, it is possible to easily adjust the positions and orientations of these components to the correct positions and orientations.

[0143] In the present embodiment, the base member 413 is provided with the positioning portion 425 , but the base member 413 may not be provided with the positioning portion 425 .

[0144] The beam expander 400 of this embodiment includes the driving mechanism 430 , but may not include the driving mechanism.

[0145] The drive mechanism 430 of this embodiment includes a rotation mechanism capable of rotating the base member 413 about an axis 430c and a movement mechanism capable of moving the base member 413 in a direction parallel to the extension direction of the base member 413, but is not limited thereto. The drive mechanism 430 only needs to include at least one of the aforementioned rotation mechanism and movement mechanism. Other examples of the beam expander 400 will be described using the following variations.

[0146] Figure 14 is with Figure 3 Similarly, a schematic diagram of an example of the general structure of the amplifier 160 in a modified example of embodiment 3 is shown. The main difference between the drive mechanism 430 of this modified example and the drive mechanism 430 of embodiment 3 is that it is composed of a rotating mechanism that can rotate the base member 413 around an axis 430c perpendicular to the extending direction of the base member 413. Figure 14 , the slit member 420 is shown to be arranged on the base member 413 . However, when the laser beam is emitted from the gas laser device 100 , the slit member 420 is removed.

[0147] In this variation, the axis 430c passes through the center of the slit 421h when the slit member 420 is positioned at a predetermined position and is perpendicular to the direction in which the base member 413 extends. By configuring the drive mechanism 430 as such a rotation mechanism, the beam expander 400 can be configured similarly to Embodiment 3 even without including a movement mechanism capable of moving the base member 413 in a direction parallel to the direction in which the base member 413 extends. Therefore, according to this variation, the structure of the beam expander 400 can be simplified.

[0148] 6. Description of the Gas Laser Device of Embodiment 4

[0149] Next, a gas laser device 100 according to Embodiment 4 will be described. The same reference numerals are used for components identical to those described above, and duplicate descriptions will be omitted unless otherwise specified. Furthermore, in some drawings, some components are omitted or simplified for easier viewing.

[0150] 6.1 Structure

[0151] Figure 15 is with Figure 3 Similarly, a schematic diagram is shown of a schematic configuration example of the amplifier 160 of this embodiment. The amplifier 160 of this embodiment mainly differs from the amplifier 160 of the first embodiment in that the resonator is a ring-type resonator.

[0152] Furthermore, the amplifier 160 of this embodiment differs from the amplifier 160 of the first embodiment in that a prism 375 is included instead of the rear mirror 371 , and an optical transmission unit 376 is included.

[0153] In this embodiment, laser light from the laser oscillator 130 is incident on the output coupling mirror 370. The output coupling mirror 370 transmits a portion of the laser light toward the light transmission unit 376 and reflects the other portion of the laser light toward the detection unit 153. Furthermore, the output coupling mirror 370 reflects a portion of the laser light emitted from the chamber device CH3 and having its beam width expanded by the beam expander 400 toward the light transmission unit 376 and transmits the other portion of the laser light toward the detection unit 153.

[0154] The optical transmission unit 376 is arranged closer to the output coupling mirror 370 than the chamber device CH3, and includes a reflecting mirror 377, a resonator concave mirror 378, and a resonator convex mirror 379. The reflecting mirror 377, the resonator concave mirror 378, and the resonator convex mirror 379 are each fixed to a holder (not shown).

[0155] The reflecting mirror 377 reflects the laser light from the output coupling mirror 370 toward the cavity concave mirror 378 .

[0156] The cavity concave mirror 378 has the same structure as the concave mirror 412 and includes a reflecting surface 378s having the same structure as the reflecting surface 412s. The cavity concave mirror 378 reflects the laser light reflected by the reflecting mirror 377 so as to reduce the beam width in the direction collimated by the concave mirror 412.

[0157] The resonator convex mirror 379 has the same structure as the convex mirror 411 and includes a reflective surface 379s having the same structure as the reflective surface 411s. The resonator convex mirror 379 collimates the laser beam reflected by the resonator concave mirror 378 to maintain a constant beam width after the beam is narrowed, and reflects the beam back to the chamber device CH3. With this optical transmission unit 376, the beam width of the laser beam expanded by the beam expander 400 remains approximately the same as the beam width before expansion, and the laser beam returns to the interior of the housing 330 through the window 331a.

[0158] The prism 375 returns the laser light emitted from the window 331b of the housing 330 through the window 331b to the interior space of the housing 330. Thus, the output coupling mirror 370, the prism 375, and the optical transmission unit 376 form a ring-shaped resonator for laser light resonance.

[0159] 6.2 Actions and Effects

[0160] Like the gas laser device 100 of the first embodiment, the gas laser device 100 of the present embodiment can also suppress the temporal degradation of the beam expander 400 . As a result, the temporal degradation of the gas laser device 100 can be suppressed.

[0161] The optical transmission unit 376 of this embodiment includes a reflector 377, a resonator concave mirror 378, and a resonator convex mirror 379, but is not limited thereto. For example, the laser light from the output coupling mirror 370 may be incident on the resonator concave mirror 378 without passing through the reflector 377. In this case, for example, the laser light reflected by the resonator convex mirror 379 may be reflected toward the chamber device CH3 by a reflector disposed between the resonator convex mirror 379 and the chamber device CH3. Furthermore, the optical transmission unit 376 may include at least one prism in place of the resonator concave mirror 378 and the resonator convex mirror 379. In this case, the at least one prism reduces the beam width of the laser light reflected by the reflector 377 in the direction collimated by the concave mirror 412, so that the beam width is approximately the same as the beam width before amplification. This laser light is then returned to the interior of the housing 330 through the window 331a.

[0162] The above description is not limiting but simply illustrative. Therefore, it is obvious to those skilled in the art that the embodiments of the present disclosure can be changed without departing from the scope of the claims. In addition, it is also obvious to those skilled in the art that the embodiments of the present disclosure can be used in combination. Unless otherwise specified, the terms used in this specification and claims should be interpreted as "non-restrictive" terms. For example, terms such as "including", "having", "equipped", etc. should be interpreted as "not excluding the presence of structural elements other than the structural elements described". In addition, the modifier "one" should be interpreted as meaning "at least one" or "one or more". In addition, the term "at least one of A, B and C" should be interpreted as "A", "B", "C", "A+B", "A+C", "B+C" or "A+B+C", and should be interpreted as also including combinations of them with structures other than "A", "B", "C".

Claims

1. A gas laser device that amplifies laser light output from a laser oscillator using an amplifier and emits the amplified laser light. The amplifier comprises: a chamber device that transmits the laser light from the laser oscillator and includes a pair of discharge electrodes facing each other in an internal space enclosing a laser gas, and amplifies the laser light from the laser oscillator by applying a voltage between the pair of discharge electrodes; a resonator that causes the laser light emitted from the chamber device to resonate between two sides sandwiching the chamber device; as well as Beam expander, The resonator includes an output coupling mirror, which is arranged on one side sandwiching the cavity device, and transmits a portion of the laser light emitted from the cavity device and reflects another portion of the laser light emitted from the cavity device back to the cavity device. The beam expander is arranged between the chamber device and the output coupling mirror, The beam expander comprises: a convex mirror including a reflecting surface that reflects the laser light emitted from the chamber device in such a manner as to expand a beam width of the laser light; as well as A concave mirror includes a reflecting surface that reflects the laser light toward the output coupling mirror in a manner that collimates the laser light reflected by the convex mirror so that the expanded beam width of the laser light remains constant.

2. The gas laser device according to claim 1, wherein The convex mirror reflects the laser light emitted from the chamber device so as to expand the beam width of the laser light in a direction in which the pair of discharge electrodes face each other and in a direction perpendicular to the optical axis of the laser light.

3. The gas laser device according to claim 2, wherein: The reflecting surface of the convex mirror and the reflecting surface of the concave mirror have a parabolic cross-sectional shape perpendicular to a direction in which the pair of discharge electrodes face each other.

4. The gas laser device according to claim 1, wherein The output coupling mirror extends to a position intersecting an optical axis of the laser light from the chamber device toward the convex mirror.

5. The gas laser device according to claim 1, wherein The beam expander further includes a plate-shaped base member extending in a direction parallel to the optical axis of the laser light from the chamber device toward the convex mirror, and having the convex mirror and the concave mirror arranged on a main surface thereof.

6. The gas laser device according to claim 5, wherein: The base member is provided with a positioning portion, and when the slit member provided with the slit is arranged at a predetermined position of the base member closer to the chamber device than the convex mirror, the positioning portion can position the slit member at the predetermined position. The optical axis of the laser light directed from the chamber device toward the convex mirror passes through the slit of the slit member disposed at the predetermined position.

7. The gas laser device according to claim 6, wherein: The gap is circular.

8. The gas laser device according to claim 6, wherein The gap is rectangular.

9. The gas laser device according to claim 5, wherein The output coupling mirror is arranged on the base component.

10. The gas laser device according to claim 5, wherein The beam expander further includes at least one of a rotating mechanism and a moving mechanism, wherein the rotating mechanism is capable of rotating the base component around an axis perpendicular to the extension direction of the base component, and the moving mechanism is capable of moving the base component in a direction parallel to the extension direction of the base component.

11. The gas laser device according to claim 6, wherein The beam expander further includes a rotation mechanism capable of rotating the base member about an axis that passes through a center of the slit and is perpendicular to an extending direction of the base member when the slit member is arranged at the predetermined position.

12. The gas laser device according to claim 11, wherein The output coupling mirror is arranged on the base component.

13. The gas laser device according to claim 1, wherein The resonator is a Fabry-Perot type resonator.

14. The gas laser device according to claim 1, wherein The resonator is a ring-type resonator.

15. The gas laser device according to claim 14, wherein The resonator further comprises: a resonator concave mirror disposed closer to the output coupling mirror than the cavity device and including a reflecting surface for reflecting the laser light collimated by the concave mirror and reflected by the output coupling mirror so as to reduce the beam width of the laser light in the direction of collimation by the concave mirror; and A convex mirror for a resonator is arranged at a position closer to the output coupling mirror than the cavity device and includes a reflecting surface. The reflecting surface collimates the laser light reflected by the concave mirror for a resonator so that the narrowed beam width is constant, and reflects the laser light in a manner returning to the cavity device.

16. A method for manufacturing an electronic device, comprising generating pulsed laser light using a gas laser device. Outputting the pulse laser to an exposure device, and exposing the pulsed laser on a photosensitive substrate in the exposure device for manufacturing an electronic device, wherein, The gas laser device amplifies the laser light output from the laser oscillator using an amplifier and emits the amplified laser light. The amplifier comprises: a chamber device that transmits the laser light from the laser oscillator and includes a pair of discharge electrodes facing each other in an internal space enclosing a laser gas, and amplifies the laser light from the laser oscillator by applying a voltage between the pair of discharge electrodes; a resonator that causes the laser light emitted from the chamber device to resonate between two sides sandwiching the chamber device; as well as Beam expander, The resonator includes an output coupling mirror, which is arranged on one side sandwiching the cavity device, and transmits a portion of the laser light emitted from the cavity device and reflects another portion of the laser light emitted from the cavity device back to the cavity device. The beam expander is arranged between the chamber device and the output coupling mirror, The beam expander comprises: a convex mirror for reflecting the laser light emitted from the chamber device so as to expand the beam width of the laser light; as well as A concave mirror reflects the laser light toward the output coupling mirror in a manner that collimates the laser light reflected by the convex mirror so that the beam width expanded thereby becomes constant.

Images