Chamber for gas laser apparatus, gas laser apparatus, and method for manufacturing electronic device

Abstract

A chamber for a gas laser device in which a laser gas is sealed in an internal space, the chamber comprising: an anode disposed in the internal space and having a longitudinal direction along a predetermined direction; a cathode disposed in the internal space, including a base and a discharge portion protruding from the base toward the anode, the length direction of the cathode being along a predetermined direction, the cathode being spaced apart from the anode and facing the anode; a cathode-side cover disposed in the internal space, separated from a part of the susceptor and the discharge portion, and covering the susceptor; and a cathode-side sound-absorbing member provided in a gap between a part of the susceptor and the cathode-side cover.

Description

Technical Field

[0001] The present disclosure relates to a chamber of a gas laser device, 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 improve resolution as semiconductor integrated circuits become increasingly miniaturized and highly integrated. Consequently, there has been a trend toward shortening the wavelength of light emitted by 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 nm, and ArF excimer lasers, which output laser light with a wavelength of approximately 193 nm.

[0003] The spectral line width of the natural oscillation light of KrF excimer laser devices and ArF excimer laser devices is as wide as 350pm to 400pm. Therefore, if the projection lens is made of a material that allows ultraviolet rays such as KrF and ArF lasers to pass through, chromatic aberration may sometimes 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 (etalon, grating, etc.) is sometimes provided in the laser resonator of the gas laser device. Hereinafter, a 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: U.S. Patent No. 6,639,929

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 6-85350

[0008] Patent Document 3: Japanese Patent No. 4579002

[0009] Patent Document 4: Japanese Patent No. 4918699

[0010] Patent Document 5: U.S. Patent Application Publication No. 2022 / 0091515 Summary of the Invention

[0011] A chamber of a gas laser device according to one embodiment of the present disclosure can enclose laser gas in an internal space, wherein the chamber comprises: an anode, which is arranged in the internal space and has a length direction along a predetermined direction; a cathode, which is arranged in the internal space and includes a base and a discharge portion protruding from the base toward the anode, the length direction of the cathode being along the predetermined direction, and the cathode being separated from and opposite to the anode; a cathode side cover, which is arranged in the internal space, is separated from a portion of the base and the discharge portion, and covers the base; and a cathode side sound absorbing component, which is arranged in a gap between a portion of the base and the cathode side cover.

[0012] A gas laser device according to one embodiment of the present disclosure may include a chamber in which laser gas is sealed in an internal space, wherein the chamber includes: an anode, which is arranged in the internal space and has a length direction along a predetermined direction; a cathode, which is arranged in the internal space and includes a base and a discharge portion protruding from the base toward the anode, the length direction of the cathode being along the predetermined direction, and the cathode being separated from and opposite to the anode; a cathode side cover, which is arranged in the internal space, is separated from a portion of the base and the discharge portion, and covers the base; and a cathode side sound absorbing component, which is arranged in a gap between a portion of the base and the cathode side cover.

[0013] A method for manufacturing an electronic device according to one embodiment of the present invention may also include the following steps: generating a laser using a gas laser device having a chamber; outputting the laser to an exposure device; and exposing the laser on a photosensitive substrate in the exposure device to manufacture the electronic device, wherein the chamber is a chamber in which laser gas is sealed in an internal space, and the chamber includes: an anode, which is arranged in the internal space and has a length direction along a prescribed direction; a cathode, which is arranged in the internal space and includes a base and a discharge portion protruding from the base toward the anode, and the length direction of the cathode is along the prescribed direction, and is separated from and opposite to the anode; a cathode side cover, which is arranged in the internal space, is separated from a portion of the base and the discharge portion, and covers the base; and a cathode side sound absorbing component, which is arranged in a gap between a portion of the base and the cathode side cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings, merely as examples.

[0015] Figure 1 This is a schematic diagram showing an example of the overall schematic configuration of an electronic device manufacturing apparatus.

[0016] Figure 2 It is a schematic diagram showing an overall schematic configuration example of a gas laser device according to a comparative example.

[0017] Figure 3 It is a VH cross-sectional view of the chamber of the comparative example.

[0018] Figure 4 yes Figure 3 A VH cross-sectional view of the periphery of the cathode is shown.

[0019] Figure 5 yes Figure 3 A VH cross-sectional view of the periphery of the cathode is shown.

[0020] Figure 6 yes Figure 3 A VH cross-sectional view of the periphery of the cathode is shown.

[0021] Figure 7 This is a VH cross-sectional view of the periphery of the cathode in the first embodiment.

[0022] Figure 8 This is a VH cross-sectional view of the periphery of the cathode in Modification 1 of Embodiment 1.

[0023] Figure 9 This is a VH cross-sectional view of the periphery of the cathode in Modification 2 of Embodiment 1.

[0024] Figure 10 This is a VH cross-sectional view of the periphery of the cathode in Modification 3 of Embodiment 1.

[0025] Figure 11 This is a VH cross-sectional view of the periphery of the cathode in Modification 4 of Embodiment 1.

[0026] Figure 12 This is a side view of the cathode and the cathode-side sound absorbing member in Embodiment 2 as viewed from the upstream side along the H direction.

[0027] Figure 13 yes Figure 12 A cross-sectional view of the periphery of the cathode at line AA is shown.

[0028] Figure 14 yes Figure 12 A cross-sectional view of the periphery of the cathode at line BB is shown.

[0029] Figure 15 yes Figure 12 A cross-sectional view of the periphery of the cathode at line CC is shown.

[0030] Figure 16 This is a VH cross-sectional view of the periphery of the anode in the third embodiment.

[0031] Figure 17 This is a VH cross-sectional view of the periphery of the anode in the fourth embodiment.

[0032] Figure 18 This is a perspective view of the outer electrode of the pre-ionization electrode in the fourth embodiment.

[0033] Figure 19 This is a VZ cross-sectional view of the groove of Modification 1 of the fourth embodiment.

[0034] Figure 20 yes Figure 19 A cross-sectional view of the periphery of the groove at line EE is shown.

[0035] Figure 21 yes Figure 19 A cross-sectional view of the periphery of the groove at line FF is shown.

[0036] Figure 22 This is a VZ cross-sectional view of the groove of Modification 2 of Embodiment 4.

[0037] Figure 23 This is a plan view of the periphery of the anode in the fifth embodiment.

[0038] Figure 24 This is a plan view of the periphery of the anode in a modified example of the fifth embodiment.

[0039] Figure 25 yes Figure 24 A cross-sectional view of the periphery of the groove at line GG is shown.

[0040] Figure 26 yes Figure 24 A cross-sectional view of the periphery of the groove at line HH is shown.

[0041] Figure 27 yes Figure 24 A cross-sectional view of the periphery of the groove at line II is shown. DETAILED DESCRIPTION

[0042] 1. Description of the electronic device manufacturing apparatus used in the exposure process of the electronic device

[0043] 2. Description of the Gas Laser Device of the Comparative Example

[0044] 2.1 Structure

[0045] 2.2 Action

[0046] 2.3 Topics

[0047] 3. Description of the Chamber in Embodiment 1

[0048] 3.1 Structure

[0049] 3.2 Function and effect

[0050] 4. Description of the Chamber in Embodiment 2

[0051] 4.1 Structure

[0052] 4.2 Function and effect

[0053] 5. Description of the Chamber in Embodiment 3

[0054] 5.1 Structure

[0055] 5.2 Function and effect

[0056] 6. Description of the Chamber in Embodiment 4

[0057] 6.1 Structure

[0058] 6.2 Action and Effect

[0059] 7. Description of the Chamber of Embodiment 5

[0060] 7.1 Structure

[0061] 7.2 Action and Effect

[0062] 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, not all of the structures and actions described in each embodiment are required to be the structures and actions of the present disclosure. In addition, the same reference numerals are attached to the same components, and repeated descriptions are omitted.

[0063] 1. Description of the electronic device manufacturing apparatus used in the exposure process of the electronic device

[0064] 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 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 optical system 210 and a projection optical system 220. The illumination optical system 210 has a plurality of mirrors 211, 212, and 213. The illumination optical system 210 uses the laser light incident from the gas laser device 100 to illuminate the mask pattern of the mask (not shown) arranged on the mask stage RT. The projection optical system 220 reduces and projects the laser light transmitted through the mask so that it is imaged on the workpiece (not shown) arranged on the workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a photoresist. The exposure device 200 exposes the workpiece with the laser light reflecting the mask pattern by moving the mask stage RT and the workpiece stage WT in parallel in synchronization. By transferring the device pattern to the semiconductor wafer through the exposure process as described above, semiconductor devices as electronic devices can be manufactured.

[0065] 2. Description of the Gas Laser Device of the Comparative Example

[0066] 2.1 Structure

[0067] A comparative example gas laser device 100 will be described. Note that the comparative examples disclosed herein are methods that the applicant has recognized as being known only to the applicant, and are not examples that the applicant considers to be publicly known.

[0068] Figure 2 : This is a schematic diagram showing an example of the overall schematic structure of a gas laser device 100 of a comparative example. The gas laser device 100 is, for example, an ArF excimer laser device using 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 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 using 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 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.

[0069] The gas laser device 100 includes a housing 110 , a laser oscillator 130 disposed in an internal space of the housing 110 , a monitoring module 160 , an aperture 170 , and a laser processor 190 as main components.

[0070] The laser oscillator 130 includes a chamber 131, a charger 141, a pulse power module 143, a narrowband module 145, and an output coupling mirror 147. Figure 2 , the internal structure of the chamber 131 is shown when viewed from a direction substantially perpendicular to the traveling direction of the laser light.

[0071] Examples of materials for chamber 131 include nickel-plated aluminum or nickel-plated stainless steel. Chamber 131 includes an internal space enclosing the laser gas described above, in which light is generated by excitation of the laser medium within the laser gas. This light travels toward windows 139a and 139B, described later. Laser gas is supplied from a laser gas supply source (not shown) to the internal space of chamber 131 through unillustrated piping. Furthermore, the laser gas within chamber 131 is treated with a halogen filter to remove F₂ gas, and then exhausted to the exterior of housing 110 by an unillustrated exhaust pump through unillustrated piping.

[0072] Within the interior of chamber 131, cathode 400, serving as the first main electrode, and anode 500, serving as the second main electrode, are spaced apart and opposed to each other, with their respective longitudinal directions aligned with the direction of laser light propagation. Hereinafter, the longitudinal directions of cathode 400 and anode 500 will sometimes be referred to as the Z direction, the direction perpendicular to the Z direction in the direction of separation between cathode 400 and anode 500 will be referred to as the V direction, and the direction perpendicular to both the V and Z directions will be referred to as the H direction. Cathode 400 and anode 500 are discharge electrodes used to excite the laser medium through glow discharge.

[0073] Cathode 400 is fixed to the surface of plate-shaped electrical insulating portion 135 located on the interior space side of chamber 131 by a conductive member 157, for example, formed by bolts. Conductive member 157 is electrically connected to pulse power module 143, and a high voltage from pulse power module 143 is applied to cathode 400. Anode 500 is supported by and electrically connected to ground plate 137.

[0074] The electrical insulating portion 135 includes an insulator. Examples of materials for the electrical insulating portion 135 include alumina ceramics, which have low reactivity with F₂ gas. Furthermore, the electrical insulating portion 135 only needs to have electrical insulating properties. Examples of materials for the electrical insulating portion 135 include resins such as phenolic resin and fluororesin, as well as quartz and glass. The electrical insulating portion 135 blocks the opening provided in the chamber 131 and is fixed to the chamber 131.

[0075] Charger 141 is a DC power supply device that charges a charging capacitor (not shown) in pulse power module 143 at a predetermined voltage. Pulse power module 143 includes switch 143a controlled by laser processor 190. When switch 143a is switched from off to on, pulse power module 143 generates a pulsed high voltage based on the electrical energy stored in the charging capacitor and applies this high voltage between cathode 400 and anode 500.

[0076] When a high voltage is applied between cathode 400 and anode 500, discharge occurs. The energy of the discharge excites the laser medium in chamber 131, and the excited laser medium emits light when it transitions to a ground state.

[0077] A pair of windows 139a and 139b are provided on the wall of chamber 131. Window 139a is located on one side of the laser beam's direction of travel within chamber 131, while window 139b is located on the other side. Windows 139a and 139b sandwich the discharge space between cathode 400 and anode 500. Windows 139a and 139b are tilted at a Brewster's angle relative to the laser beam's direction of travel to suppress reflection of P-polarized laser light. Laser light oscillating as described below is emitted from windows 139a and 139b to the exterior of chamber 131. As described above, a pulsed high voltage is applied between cathode 400 and anode 500 by pulse power module 143, resulting in pulsed laser light.

[0078] The narrowband module 145 includes a housing 145a, a prism 145b, a grating 145c, and a rotating stage (not shown) disposed in the interior of the housing 145a. The housing 145a has an opening, and the housing 145a is connected to the rear side of the chamber 131 through the opening.

[0079] The prism 145B expands the beam width of the light emitted from the window 139a, causing the light to be incident on the grating 145c. In addition, the prism 145b reduces the beam width of the reflected light from the grating 145c, and causes the light to return to the internal space of the chamber 131 via the window 139a. The prism 145b is supported by a rotating stage and rotated by the rotating stage. The rotation of the prism 145b changes the incident angle of the light to the grating 145c. Therefore, the rotation of the prism 145b makes it possible to select the wavelength of the light that returns from the grating 145c via the prism 145b to the chamber 131. Figure 2 , an example in which one prism 145 b is arranged is shown, but at least one prism only needs to be arranged.

[0080] The surface of grating 145c is made of a high-reflectivity material and has multiple grooves arranged at predetermined intervals. The cross-sectional shape of each groove is, for example, a right triangle. When light incident on grating 145c from prism 145b is reflected by these grooves, it is diffracted in a direction corresponding to the wavelength of the light. Grating 145c is configured by Littrow so that the angle of incidence of light incident on grating 145c from prism 145B coincides with the diffraction angle of diffracted light of the desired wavelength. As a result, light near the desired wavelength is returned to chamber 131 via prism 145b.

[0081] Output coupling mirror 147 is located within the interior of optical tube 147a, connected to the front of chamber 131, facing window 139b. Output coupling mirror 147 transmits a portion of the laser light emitted from window 139b toward monitoring module 160, while reflecting the remaining portion, returning it through window 139b to the interior of chamber 131. Thus, grating 145c and output coupling mirror 147 form a Fabry-Perot laser resonator, with chamber 131 positioned in the optical path of the laser resonator. Light from chamber 131 travels toward monitoring module 160.

[0082] Monitoring module 160 is disposed on the optical path of the laser light emitted from output coupling mirror 147. Monitoring module 160 includes a housing 161, a beam splitter 163 disposed within the interior of housing 161, and a light sensor 165. Housing 161 has an opening formed therein, and the interior of housing 161 communicates with the interior of optical tube 147a through the opening.

[0083] Beam splitter 163 transmits a portion of the laser light emitted from output coupling mirror 147 toward aperture 170 and reflects the remaining portion toward the light-receiving surface of optical sensor 165. Optical sensor 165 measures the energy E of the laser light incident on the light-receiving surface and outputs a signal indicating the measured energy E to laser processor 190.

[0084] The laser processor 190 of the present disclosure is a processing device comprising a storage device 190a storing a control program and a CPU (Central Processing Unit) 190B that executes the control program. Laser processor 190 is specifically configured or programmed to perform the various processes included in the present disclosure. Furthermore, laser processor 190 controls the entire gas laser device 100.

[0085] The laser processor 190 exchanges various signals with the exposure processor 230 of the exposure device 200. For example, the laser processor 190 receives signals indicating the emission trigger Tr (described later) and the target energy Et from the exposure processor 230. The target energy Et is the target value for the laser energy used in the exposure process. The laser processor 190 controls the charge voltage of the charger 141 based on the energy E and the target energy Et received from the optical sensor 165 and the exposure processor 230. By controlling this charge voltage, the laser energy is controlled. Furthermore, the laser processor 190 sends a command signal to the pulse power module 143 to turn on or off the switch 143a. Furthermore, the laser processor 190 is electrically connected to the aperture 170 and controls the opening and closing of the aperture 170.

[0086] The laser processor 190 closes the aperture 170 until the difference ΔE between the energy E received from the monitoring module 160 and the target energy Et received from the exposure processor 230 falls within the allowable range. If the difference ΔE falls within the allowable range, the laser processor 190 transmits a reception preparation completion signal to the exposure processor 230, notifying the exposure processor 230 that the reception preparation for the light emission trigger Tr is complete. Upon receiving the reception preparation completion signal, the exposure processor 230 transmits a signal indicating the light emission trigger Tr to the laser processor 190. Upon receiving the signal indicating the light emission trigger Tr, the laser processor 190 opens the aperture 170. The light emission trigger Tr is defined by a predetermined laser repetition frequency f and a predetermined pulse number P. It is a timing signal that the exposure processor 230 uses to start the laser oscillator 130 and is an external trigger. The laser repetition frequency f is, for example, between 100 Hz and 10 kHz.

[0087] The aperture 170 is arranged on the optical path of the laser light in the internal space of the optical tube 171. The optical tube 171 is connected to an opening formed in the housing 161 of the monitoring module 160 on the side opposite to the side connected to the optical tube 147a. The internal spaces of the optical tubes 171 and 147a and the internal spaces of the housings 161 and 145a are supplied and filled with a purge gas. The purge gas contains an inert gas such as nitrogen (N2). The purge gas is supplied from a purge gas supply source (not shown) through a pipe (not shown). In addition, the optical tube 171 is connected to the exposure device 200 through an opening in the housing 110 and an optical tube 300 connecting the housing 110 and the exposure device 200. The laser light passing through the aperture 170 is incident on the exposure device 200.

[0088] The exposure processor 230 of the present disclosure is a processing device including a storage device 230a storing a control program and a CPU 230b executing the control program. The exposure processor 230 is specially configured or programmed to perform various processes included in the present disclosure. In addition, the exposure processor 230 controls the entire exposure device 200.

[0089] Figure 3 1 is a VH cross-sectional view of the chamber 131 of the comparative example. A cross-flow fan 149 and a heat exchanger 151 are further arranged in the internal space of the chamber 131.

[0090] The cross-flow fan 149 and the heat exchanger 151 are arranged on the side opposite to the anode 500 side with respect to the ground plate 137. In the internal space of the chamber 131, the space where the cross-flow fan 149 and the heat exchanger 151 are arranged is connected to the discharge space between the cathode 400 and the anode 500. The heat exchanger 151 is arranged next to the cross-flow fan 149 and is a radiator connected to a pipe (not shown) for the flow of liquid or gas, i.e., a cooling medium. Figure 2As shown, the cross flow fan 149 is connected to a motor 149a disposed outside the chamber 131 and rotates by the rotation of the motor 149a. As the cross flow fan 149 rotates, the laser gas sealed in the inner space of the chamber 131 is Figure 3 The laser gas circulates as indicated by the bold arrows. Specifically, the laser gas circulates in the order of the crossflow fan 149, the discharge space between the cathode 400 and the anode 500, the heat exchanger 151, and the crossflow fan 149. At least a portion of the circulating laser gas passes through the heat exchanger 151, where the temperature of the laser gas is regulated. Through the circulation of the laser gas, impurities in the laser gas generated by the main discharge between the cathode 400 and the anode 500 migrate downstream, allowing fresh laser gas to be supplied to the discharge space between the cathode 400 and the anode 500 during the subsequent discharge. Furthermore, as the laser gas passes through the heat exchanger 151, the heat generated by the main discharge is removed, suppressing the temperature rise of the laser gas. The on / off switching and rotational speed of the motor 149a are controlled by the laser processor 190. Therefore, by controlling the motor 149a, the laser processor 190 can adjust the circulation speed of the laser gas circulating within the interior space of the chamber 131.

[0091] The ground plate 137 is electrically connected to the chamber 131 via a wiring 137a. The anode 500 supported by the ground plate 137 is connected to the ground potential via the ground plate 137, the wiring 137a, and the chamber 131.

[0092] An anode side cover 550 is disposed on the ground plate 137, covering the side of the anode 500. The anode side cover 550 includes cover members 551, 553, and 555, which are arranged in order from upstream to downstream of the laser gas flow. Cover member 551 is fixed to the ground plate 137 with bolts (not shown). The preionization electrode 10 is disposed between cover member 551 and cover member 553, and cover member 553 and cover member 555 sandwich the anode 500. The anode 500 is fixed to the ground plate 137 with bolts (not shown), and the cover members 553 and 555 are fixed to the anode 500 with bolts (not shown). Examples of materials for each of the cover members 551, 553, and 555 include porous nickel metal, which has low reactivity with F2 gas. Cover members 551 , 553 , and 555 guide the laser gas so that the laser gas flows from cross flow fan 149 to heat exchanger 151 through the discharge space between cathode 400 and anode 500 due to the air blown by cross flow fan 149 .

[0093] The preionization electrode 10 is disposed on the ground plate 137 to the side of the anode 500 in the H direction. In this example, the preionization electrode 10 is disposed upstream of the anode 500. The preionization electrode 10 includes a dielectric tube 11, a preionization inner electrode, and a preionization outer electrode. Hereinafter, the preionization inner electrode and the preionization outer electrode may be referred to as the inner electrode 13 and the outer electrode 15, respectively.

[0094] The dielectric tube 11 is, for example, a cylindrical member, and extends in the Z direction. Examples of the material of the dielectric tube 11 include alumina ceramics and sapphire.

[0095] The internal electrode 13 is rod-shaped and is disposed inside the dielectric tube 11, extending along the longitudinal direction of the dielectric tube 11. Examples of the material of the internal electrode 13 include copper and brass.

[0096] The external electrode 15 is disposed between the dielectric tube 11 and the cover member 553, extending along the longitudinal direction of the dielectric tube 11. The external electrode 15 includes an end portion 15a that faces a portion of the outer circumferential surface of the dielectric tube 11. This end portion 15a extends from one end of the external electrode 15 to the other end in the longitudinal direction of the external electrode 15. The external electrode 15 is curved in a plane perpendicular to the longitudinal direction of the dielectric tube 11. This curvature causes the end portion 15a to contact the outer circumferential surface of the dielectric tube 11, pressing against the outer circumferential surface. A portion of the outer circumferential surface of the dielectric tube 11 approximately opposite the portion of contact with the end portion 15a of the external electrode 15 contacts the cover member 551. Therefore, even when the external electrode 15 presses against the dielectric tube 11, the dielectric tube 11 is supported by the cover member 551. A threaded hole (not shown) is provided at the end of the external electrode 15 opposite the end portion 15a. The external electrode 15 is secured to the cover member 553 by a screw (not shown) threaded into the threaded hole. Therefore, it can be understood that the external electrode 15 is fixed to the anode 500 via the cover member 553. Examples of the material of the external electrode 15 include copper and brass.

[0097] A pair of cathode side covers 450 are disposed on the surface of the electrically insulating portion 135 facing the interior space of the chamber 131. These cathode side covers 450 are disposed on the upstream and downstream sides of the cathode 400, extending along the cathode 400 in the Z direction and being separate components. Each cathode side cover 450 is secured to the electrically insulating portion 135 by bolts (not shown). The cathode side covers 450 have a roughly right-angled triangular cross-section, gradually increasing in height in the V direction as they approach the cathode 400 in the H direction. These cathode side covers 450 guide the laser gas in the same manner as the anode side cover 550.

[0098] Figure 4 yes Figure 3 The VH cross-sectional view of the periphery of the cathode 400 is shown. Figure 4In the figure, the laser gas flowing in the discharge space between the cathode 400 and the anode 500 is represented by a thick arrow. The cathode 400 includes a base 401 fixed to the electrical insulating portion 135 and a discharge portion 403 protruding from the base 401 toward the anode 500. The cross-sectional shape of the base 401 is a rectangle that is longer in the H direction, and the cross-sectional shape of the discharge portion 403 is a rectangle that is longer in the V direction. The base 401 and the discharge portion 403 extend along the Z direction, and their length in the Z direction is substantially the same as that of the cathode 400. The discharge portion 403 is provided on the surface of the base 401 on the opposite side to the electrical insulating portion 135. The width of the base 401 in the H direction is wider than that of the discharge portion 403, and the surfaces 401a included in the above-mentioned opposite side surfaces are provided on the left and right of the discharge portion 403 in the H direction. In Figure 3 and Figure 4 In the figure, for ease of observation, only the left side surface 401a is marked with reference numerals. The side surface of the base 401 provided in the VZ plane abuts against a portion of the side surface 451 of the cathode side cover 450, while the side surface of the discharge portion 403 does not abut against the side surface 451. In addition, the discharge portion 403 extends further toward the anode 500 than the protrusion 453 described later of the cathode side cover 450. In addition, Figure 2 , the illustration of cathode 400 is simplified.

[0099] The protrusion 453 of the cathode side cover 450 protrudes in the H direction from the side surface 451 of the cathode side cover 450 toward the side surface of the discharge section 403. The protrusion 453 is separated from the discharge section 403 in the H direction and from the surface 401a, which is part of the base 401, in the V direction. When viewed from the V direction, the protrusion 453 overlaps with the surface 401a. Furthermore, the protrusion 453 extends in the Z direction, and its length in the Z direction is approximately the same as that of the cathode 400. This protrusion 453 covers the base 401, with a gap 40 defined between the protrusion 453 and the base 401. The gap 40 is a roughly L-shaped space enclosed by the entrance 41 of the gap 40, which is provided between the side surface of the discharge section 403 and the protrusion 453, the protrusion 453, the side surface 451, the surface 401a, and the side surface of the discharge section 403. Such a gap 40 is provided to avoid interference caused by dimensional errors in the manufacture of the cathode 400 and the cathode side cover 450, which may result in the cathode 400 and the cathode side cover 450 being unable to be assembled. The cathode side cover 450 forming the gap 40 covers the cathode 400 from the side. In addition, since the cathode side cover 450 is provided on the upstream side and the downstream side of the cathode 400, a gap 40 is provided separately on the upstream side and the downstream side of the cathode 400. The gap 40 and the cathode side cover 450 are aligned with the discharge portion 403 in the H direction, i.e., Figure 3 The left and right sides are set symmetrically. Figure 3 and Figure 4 In order to facilitate observation, only the gap 40 and the inlet 41 on the left are marked with reference numerals. Figure 4 Sound wave 61a is shown.

[0100] 2.2 Action

[0101] Next, the operation of the gas laser device 100 according to the comparative example will be described.

[0102] Before the gas laser device 100 emits laser light, purge gas is filled from a purge gas supply source (not shown) into the interior spaces of the optical tubes 147a, 171, and 300 and the interior spaces of the housings 145a and 161. Furthermore, laser gas is supplied from a laser gas supply source (not shown) into the interior space of the chamber 131. When the laser gas is supplied, the laser processor 190 controls the motor 149a to rotate the crossflow fan 149. The rotation of the crossflow fan 149 causes the laser gas to circulate within the interior space of the chamber 131. At this time, the laser gas is guided from the crossflow fan 149 toward the discharge space between the cathode 400 and the anode 500 by the cathode side cover 450 and the cover members 551 and 553 on the upstream side. Furthermore, the laser gas is guided from the discharge space between the cathode 400 and the anode 500 toward the heat exchanger 151 by the cathode side cover 450 and the cover member 555 on the downstream side.

[0103] When the gas laser device 100 emits laser light, the laser processor 190 receives a signal indicating the target energy Et and a signal indicating the emission trigger Tr from the exposure processor 230. Furthermore, the laser processor 190 turns on the switch 143a of the pulse power module 143. This causes the pulse power module 143 to apply a pulsed high voltage between the cathode 400 and anode 500, and between the inner electrode 13 and the outer electrode 15, using the electrical energy stored in a charging capacitor (not shown). Application of the high voltage between the inner electrode 13 and the outer electrode 15 generates a corona discharge near the dielectric tube 11 and the end 15a, emitting ultraviolet light. When ultraviolet light irradiates the laser gas between the cathode 400 and anode 500, it pre-ionizes the laser gas there. After pre-ionization, when the voltage between the cathode 400 and anode 500 reaches the dielectric breakdown voltage, a main discharge occurs between the cathode 400 and anode 500. As a result, excimer molecules are generated from the laser medium contained in the laser gas between cathode 400 and anode 500, and light is emitted when they dissociate. This light travels back and forth between grating 145c and output coupling mirror 147, and is amplified each time it passes through the discharge space within chamber 131, thereby causing laser oscillation. A portion of the laser light then passes through output coupling mirror 147 as pulsed laser light and travels toward beam splitter 163.

[0104] A portion of the laser light that has reached beam splitter 163 is reflected by beam splitter 163 and received by optical sensor 165. Optical sensor 165 measures the energy E of the received laser light and outputs a signal representing the energy E to laser processor 190. Laser processor 190 controls the charging voltage so that the difference ΔE between energy E and target energy Et falls within an allowable range. Meanwhile, another portion of the laser light that has reached beam splitter 163 passes through beam splitter 163, passes through aperture 170, and reaches exposure device 200.

[0105] 2.3 Topics

[0106] In the gas laser device 100 of the comparative example, a high temperature and high pressure state is generated in a very short time in the discharge space between the cathode 400 and the anode 500 by the main discharge between the cathode 400 and the anode 500. Figure 4 The solid line curve in FIG. 6 shows an imaginary acoustic wave 61a. Acoustic wave 61a is a compression wave of the laser gas in chamber 131, and propagates in chamber 131 while expanding from the discharge space. The propagation speed is approximately 500 m / s.

[0107] Figure 5 and Figure 6 and Figure 4 Similarly, it is a VH cross-sectional view of the periphery of the cathode 400. Figure 5 As shown, the acoustic wave 61a sometimes propagates in the gap 40 by leaving the discharge space and entering the gap 40 from the inlet 41. Figure 6 As shown, the acoustic wave 61a propagating to the gap 40 is sometimes reflected by the cathode 400 and the cathode side cover 450 around the gap 40, and returns to the discharge space as a reflected wave 61b shown by a solid line curve. Figure 5 and Figure 6 , the traveling directions of the sound wave 61a and the reflected wave 61b are indicated by thin arrows.

[0108] When reflected wave 61b returns to the discharge space at the timing of the main discharge, it changes the density distribution of the laser gas in the discharge space, destabilizing the main discharge and potentially reducing the energy stability of the laser light emitted from the gas laser device 100. This can sometimes affect laser performance. This effect tends to increase when the laser repetition rate is 2 kHz or higher. Consequently, exposure device 200 may not be able to emit laser light that meets the required performance, raising concerns about reduced reliability of the gas laser device 100.

[0109] Therefore, in the following embodiment, the chamber 131 of the gas laser device 100 that can suppress a decrease in reliability is exemplified.

[0110] 3. Description of the Chamber in Embodiment 1

[0111] Next, the chamber 131 of Embodiment 1 will be described. Components identical to those described above are denoted by the same reference numerals, and duplicate descriptions will be omitted unless otherwise specified. In some drawings, for ease of illustration, portions of components may be omitted or simplified. For identical components, only some reference numerals may be assigned, while others may be omitted.

[0112] 3.1 Structure

[0113] Figure 7 This is a VH cross-sectional view of the periphery of cathode 400 in this embodiment. In chamber 131 of this embodiment, the structure of base 401 differs from that of base 401 in the comparative example. Furthermore, chamber 131 differs from chamber 131 in the comparative example in that it further includes cathode-side sound absorbing members 470 disposed in gaps 40 on both the upstream and downstream sides of cathode 400.

[0114] The base 401 of this embodiment includes a first base 405 and a second base 407. The second base 407 is provided on the surface of the first base 405 on the opposite side to the electrical insulating portion 135. The second base 407 protrudes from the first base 405 toward the anode 500. The width of the first base 405 in the H direction is wider than that of the second base 407, and surfaces 405a included in the above-mentioned opposite side surface of the first base 405 are provided on the left and right sides of the second base 407 in the H direction. The discharge portion 403 is provided on the surface of the second base 407 on the opposite side to the first base 405. The discharge portion 403 protrudes from the second base 407 toward the anode 500. The width of the second base 407 in the H direction is wider than that of the discharge portion 403, and surfaces 407a included in the above-mentioned opposite side surface of the second base 407 are provided on the left and right sides of the H direction of the discharge portion 403. The surface 407a faces the inlet 41. In Figure 7 For ease of illustration, only the left-side surfaces 405a and 407a are labeled. First pedestal 405 abuts a portion of side surface 451 of cathode side cover 450, while second pedestal 407 does not abut side surface 451. In other words, cathode side cover 450 is separated from second pedestal 407, which is part of pedestal 401. First pedestal 405 and second pedestal 407 are positioned closer to electrical insulating portion 135 than inlet 41.

[0115] The cathode-side sound absorbing member 470 of this embodiment is disposed on the base 401, specifically, on the surface 405a of the first base 405, and is screwed to the first base 405. This cathode-side sound absorbing member 470 is positioned in the gap 40 between the second base 407, which is part of the base 401, and the side surface 451 of the cathode-side cover 450. It abuts the side surface of the second base 407 and faces the protrusion 453 and a portion of the inlet 41 of the gap 40. Furthermore, since the cathode-side sound absorbing member 470 also abuts the side surface 451 of the cathode-side cover 450, it can be understood that it is also disposed at the position farthest from the discharge space in the gap 40. In this embodiment, the region in the gap 40 through which sound waves 61a propagate is the space enclosed by the inlet 41, the protrusion 453, the side surface 451, the surface 405a, the side surface of the second base 407, the surface 407a, and the side surface of the discharge portion 403. This gap 40 is composed of an inlet 41, a first space, and a second space. The first space is connected to the inlet 41 and has a rectangular shape longer in the H direction than in the V direction. The second space is connected to the first space and located further inward from the first space. It has a rectangular shape with a longer H direction than the V direction and a narrower H direction width than the first space. The cathode-side sound absorbing member 470 extends in the Z direction and has a length substantially the same as that of the cathode 400, but may be shorter.

[0116] Cathode-side sound absorbing member 470 is, for example, made of a porous member. Examples of materials for cathode-side sound absorbing member 470 include metals such as nickel, copper, iron, stainless steel, and brass. Furthermore, cathode-side sound absorbing member 470 may be made of any porous member or an electrical insulator. Examples of materials for cathode-side sound absorbing member 470 include alumina ceramic.

[0117] 3.2 Function and effect

[0118] When a voltage is applied to the cathode 400 and anode 500, generating a main discharge between them, light is emitted from the laser gas. This light then passes through window 139b and exits chamber 131. In chamber 131 of this embodiment, the main discharge may also generate acoustic waves 61a in the discharge space between cathode 400 and anode 500. These acoustic waves 61a propagate into gap 40 between susceptor 401 and cathode-side cover 450. Acoustic waves 61a propagating into gap 40 are absorbed by cathode-side sound absorbing member 470, which is positioned there. The absorbed acoustic waves 61a propagate through the interior of cathode-side sound absorbing member 470 while repeatedly reflecting, converting to energy such as heat and gradually attenuating. Furthermore, acoustic waves 61a that have passed through cathode-side sound absorbing member 470 are reflected by susceptor 401 and cathode-side cover 450 surrounding the member and are then absorbed again by the member. As described above, the absorbed sound wave 61a is repeatedly reflected inside the cathode-side sound absorbing component 470 and further attenuated. As a result, the size of the sound wave 61a reflected inside the cathode-side sound absorbing component 470 and returned to the discharge space, i.e., the reflected wave 61b, is reduced, which can suppress the change in the density distribution of the laser gas in the discharge space caused by the reflected wave 61b, and can suppress unstable main discharge. Figure 7 For ease of visualization, the reflected wave 61b is omitted from the illustration. Furthermore, by covering the susceptor 401 with the cathode side cover 450, unnecessary discharge from the susceptor 401 during the main discharge can be suppressed. This can prevent a decrease in the energy stability of the laser light emitted from the gas laser device 100. Consequently, laser light that meets the performance required of the exposure apparatus 200 can be emitted, and a decrease in the reliability of the gas laser device 100 can be suppressed.

[0119] Furthermore, in the chamber 131 of the present embodiment, the cathode-side sound absorbing member 470 is also disposed at a position in the gap 40 that is farthest from the discharge space between the cathode 400 and the anode 500 .

[0120] Acoustic wave 61a, while being absorbed by cathode-side sound-absorbing member 470, propagates toward the location farthest from the discharge space, and thus tends to attenuate. Therefore, this configuration can attenuate acoustic wave 61a propagating toward the location farthest from the discharge space, as well as reflected wave 61b returning from cathode-side sound-absorbing member 470 to the discharge space. This can suppress changes in the laser gas density distribution in the discharge space caused by reflected wave 61b, thereby preventing unstable main discharge.

[0121] The cathode-side sound absorbing member 470 of this embodiment is disposed on the surface 405a of the first pedestal 405, but it may also be disposed on at least one of the surface 405a and the surface 407a of the second pedestal 407, or may be disposed so as to fill the entire gap 40. Furthermore, the cathode-side sound absorbing member 470 is disposed in each gap 40 on the upstream and downstream sides of the cathode 400, but it may also be disposed in at least one of the gaps 40. Alternatively, it may be disposed so as to surround the entire circumference of the cathode 400, such as the first pedestal 405 and the second pedestal 407.

[0122] In addition, the arrangement position of the cathode-side sound absorbing member 470 is not necessarily limited to the above-described position, and other examples will be described using modified examples.

[0123] Figure 8 This is a VH cross-sectional view of the periphery of cathode 400 in Modification 1 of this embodiment. In chamber 131 of this modification, cathode-side sound absorbing member 470 is separated from side surface 451 of cathode side cover 450, which differs from the present embodiment. The region in gap 40 of this modification, where sound waves 61a propagate, is a space enclosed by inlet 41, protrusion 453, side surface 451, surface 455 of cathode side cover 450 facing protrusion 453, surface 405a, side surface 407a of second base 407, and side surface 407a of discharge portion 403. This gap 40 is composed of inlet 41, a first space, and a second space, forming a cranked shape. The first space is connected to inlet 41 and is a rectangular shape longer in the H direction than in the V direction. The second space is connected to the first space and is located further inward from the first space. It is a rectangular shape longer in the V direction than in the H direction and narrower in the H direction than the first space.

[0124] Figure 9 This is a VH cross-sectional view of the periphery of cathode 400 in Variation 2 of this embodiment. The base 401 of this variation has the same structure as the base 401 of the comparative example. In the chamber 131 of this variation, a cathode-side sound absorbing member 470 is disposed on the cathode side cover 450, which differs from the present embodiment. Specifically, cathode-side sound absorbing member 470 is disposed on the surface of the protrusion 453 that is located on the side of surface 401a of base 401. In other words, cathode-side sound absorbing member 470 is disposed in the gap between surface 401a, which is part of base 401, and protrusion 453 of cathode side cover 450. Cathode-side sound absorbing member 470 is screwed to protrusion 453, abuts against side surface 451 of cathode side cover 450, and is spaced apart from and facing surface 401a.

[0125] Figure 10This is a VH cross-sectional view of the periphery of cathode 400 in Modification 3 of this embodiment. In chamber 131 of this modification, cathode-side sound absorbing member 470 is disposed on side 451 of cathode side cover 450, unlike Modification 2. Cathode-side sound absorbing member 470 is screwed to side 451. Cathode-side sound absorbing member 470 is spaced apart from the side surface of base 401 and abuts a portion of surface 455 of cathode side cover 450 and a portion of protrusion 453. Cathode-side sound absorbing member 470 also abuts the angle formed by side 451 and surface 455, so it can be understood as being disposed at the position farthest from the discharge space within gap 40. In this modification, the region within gap 40 where sound waves 61a propagate is the space enclosed by gap entrance 41, protrusion 453, side 451, surface 455, the side surface of base 401, surface 401a of base 401, and the side surface of discharge section 403. The gap 40 is composed of the inlet 41 , the first space, and the second space and has a crank shape, similar to Modification 1. The side surface 451 of the cathode side cover 450 is spaced apart from a portion of the side surface of the base 401 and abuts against another portion of the side surface of the base 401 .

[0126] In the first, second, and third modifications, the acoustic wave 61a propagating to the gap 40 is absorbed by the cathode-side sound absorbing member 470. Therefore, the magnitude of the reflected wave 61b is reduced, and the stability of the energy of the laser light emitted from the gas laser device 100 can be suppressed from decreasing.

[0127] Figure 11 This is a VH cross-sectional view of the periphery of cathode 400 in Variation 4 of this embodiment. In chamber 131 of this variation, base 401 includes a first base 405 and a second base 407, similar to base 401 of the present embodiment. This configuration combines Variations 1 to 3, with a cathode-side sound absorbing member 470 also being positioned on surface 407a of second base 407. Specifically, in chamber 131 of this variation, cathode-side sound absorbing members 470 are positioned on surface 405a, surface 407a, protrusion 453, and side surface 451. The cathode-side sound absorbing member 470 positioned on surface 407a extends in the H direction and is also positioned on the cathode-side sound absorbing member 470 positioned on surface 405a. The cathode-side sound absorbing member 470 positioned on protrusion 453 faces and is spaced apart from the cathode-side sound absorbing member 470 positioned on surface 407a of second base 407. The cathode-side sound absorbing member 470 disposed on the side surface 451 of the cathode-side cover 450 faces and is separated from the cathode-side sound absorbing members 470 disposed on the surface 405 a of the first base 405 and the surface 407 a of the second base 407 .

[0128] With this configuration, compared to a case where cathode-side sound absorbing member 470 is disposed only on either base 401 or cathode-side cover 450, sound wave 61a is absorbed by cathode-side sound absorbing member 470, further attenuating the sound wave. Consequently, the magnitude of reflected wave 61b is further reduced, further suppressing a decrease in the stability of the laser energy emitted from gas laser device 100.

[0129] 4. Description of the Chamber in Embodiment 2

[0130] Next, the chamber 131 of Embodiment 2 will be described. Components identical to those described above are denoted by the same reference numerals, and duplicate descriptions will be omitted unless otherwise specified. In some drawings, for ease of illustration, portions of components may be omitted or simplified. For identical components, only some reference numerals may be assigned, while others may be omitted.

[0131] 4.1 Structure

[0132] Figure 12 This is a side view of the cathode 400 and the cathode-side sound absorbing member 470 according to the present embodiment as viewed from the upstream side along the H direction. Figure 13 yes Figure 12 The cross-sectional view of the periphery of the cathode 400 at line AA is shown. Figure 14 yes Figure 12 The cross-sectional view of the periphery of the cathode 400 at line BB is shown. Figure 15 yes Figure 12 A cross-sectional view of the periphery of cathode 400 is shown at line CC.

[0133] The cathode-side sound absorbing member 470 of this embodiment is disposed on the surface 405a of the first base 405, as in the first variation of the first embodiment, and is separated from the side surface 451 of the cathode-side cover 450. However, in the chamber 131 of this embodiment, the structures of the surface 405a, the surface 455 of the cathode-side cover 450 that contacts the gap 40, and the cathode-side sound absorbing member 470 differ from those of the first variation of the first embodiment.

[0134] The surface 405a of the first pedestal 405 and the surface 455 of the cathode side cover 450 are gradually inclined from one side in the Z direction toward the other, moving away from the anode 500 and the protrusion 453. One side in the Z direction is located on the monitoring module 160 side, and the other side is located on the narrowing module 145 side. Therefore, the area between the side surface of the second pedestal 407 and the side surface 451 of the cathode side cover 450 in the gap 40 gradually deepens in the V direction from one side in the Z direction toward the other.

[0135] The cathode-side sound absorbing member 470 is disposed on the inclined surface 405a as described above. In this embodiment, the height of the cathode-side sound absorbing member 470 in the V direction gradually increases from one side to the other in the Z direction. Furthermore, the surface of the cathode-side sound absorbing member 470 facing the protrusion 453 is positioned at the same height from one side to the other in the Z direction, and is also positioned at the same height as the surface 407a of the second base 407. Therefore, the side surface of the second base 407 is covered by the cathode-side sound absorbing member 470.

[0136] 4.2 Function and effect

[0137] In the chamber 131 of this embodiment, the surface 455 of the cathode side cover 450 in contact with the gap 40 is perpendicular to the V direction from the anode 500 toward the cathode 400, extends along the Z direction as a predetermined direction, and is inclined from one side toward the other side in the Z direction away from the anode 500.

[0138] With this structure, the distance from the other side of surface 455 in the Z direction to the discharge space is longer than the distance from the one side of surface 455 in the Z direction to the discharge space. Therefore, when acoustic wave 61a propagating into gap 40 is reflected by surface 455, the phase of reflected wave 61b returning to the discharge space from the other side of surface 455 in the Z direction is offset from the phase of reflected wave 61b returning to the discharge space from the one side of surface 455 in the Z direction. This phase offset can prevent reflected waves 61b from returning to the discharge space all at once, compared to a situation where the phases are not offset. Consequently, changes in the density distribution of the laser gas in the discharge space caused by reflected wave 61b can be suppressed, and unstable main discharge can be prevented.

[0139] The cathode side sound absorbing member 470 of this embodiment extends in the Z direction and is disposed on the base 401. The height of the cathode side sound absorbing member 470 in the V direction from the anode 500 toward the cathode 400 increases from one side to the other in the Z direction.

[0140] With this structure, sound wave 61a absorbed by cathode-side sound absorbing member 470 is repeatedly reflected and attenuated more frequently on the other side in the Z direction than on one side in the Z direction. Consequently, reflected wave 61b returning to the discharge space from the other side in the Z direction is reduced compared to reflected wave 61b returning to the discharge space from one side in the Z direction. This reduces the change in the density distribution of the laser gas in the discharge space caused by reflected wave 61b, compared to a case where this reduction is not observed. This allows for the suppression of unstable main discharge.

[0141] While the present embodiment describes chamber 131 using Modification 1 of Embodiment 1, this is not limiting and can also be applied to Embodiment 1 and its other modifications. Specifically, cathode-side sound absorbing member 470 may be disposed on a surface perpendicular to the V-direction extending from anode 500 toward cathode 400. Examples of such surfaces include surface 405a of Embodiment 1, the surface of protrusion 453 located on the surface 401a side of base 401 in Modification 2, and surface 455 of cathode-side cover 450 in Modification 3. These surfaces may be inclined from one side in the Z-direction toward the other, moving away from anode 500.

[0142] In this embodiment, the chamber 131 is described with one side in the Z direction being the monitoring module 160 side and the other side being the narrowband module 145 side. However, the opposite may be true. In other words, one side in the Z direction may be the narrowband module 145 side and the other side may be the monitoring module 160 side.

[0143] Furthermore, the cathode side sound absorbing member 470 does not need to gradually increase in height in the V direction from one side toward the other side in the Z direction. The cathode side sound absorbing member 470 may increase in height in a step-like manner from one side toward the other side in the Z direction.

[0144] 5. Description of the Chamber in Embodiment 3

[0145] Next, the chamber 131 of Embodiment 3 will be described. Components identical to those described above are denoted by the same reference numerals, and duplicate descriptions will be omitted unless otherwise specified. In some drawings, for ease of illustration, portions of components may be omitted or simplified. For identical components, only some reference numerals may be assigned, while others may be omitted.

[0146] In the chamber 131 of each embodiment after embodiment 3 and its modified examples, the structure on the anode 500 side is mainly described, but the structure on the cathode 400 side may be the structure on the cathode 400 side of any of embodiments 1, 2 and their modified examples.

[0147] 5.1 Structure

[0148] Figure 16 This is a VH cross-sectional view of the periphery of the anode 500 in this embodiment. In the chamber 131 of this embodiment, the anode 500 includes a base 501 extending in the Z direction and a discharge portion 503. The anode side cover 550 is separate from and covers the anode 500 on the side of the anode 500, which is different from the first embodiment.

[0149] The base 501 is fixed to the ground plate 137, and the discharge portion 503 protrudes from the base 501 toward the discharge portion 403 of the cathode 400. Unlike the cathode 400, the base 501 is narrower in the H direction than the discharge portion 503, and the side surfaces of the base 501 are located further inward than the side surfaces of the discharge portion 503.

[0150] In the anode-side cover 550 , the cover member 553 and the cover member 555 are separated from the anode 500 . Therefore, gaps 50 are provided between the anode 500 and the cover member 553 , and between the anode 500 and the cover member 555 .

[0151] Furthermore, the chamber 131 of this embodiment differs from the first embodiment in that it further includes an anode-side sound absorbing member 570 disposed in the gap 50 between the anode-side cover 550 and the anode 500. The anode-side sound absorbing member 570 is disposed on the side of each of the cover member 553 and the cover member 555 facing the anode 500 and is screwed to the side. Furthermore, the anode-side sound absorbing member 570 is disposed on the upstream and downstream sides of the base 501 of the anode 500 and is screwed to each side of the base 501. Thus, four anode-side sound absorbing members 570 are disposed on the anode-side cover 550 and the anode 500, respectively. The anode-side sound absorbing members 570 disposed on the upstream side of the cover member 553 and the base 501 face each other, while the anode-side sound absorbing members 570 disposed on the downstream side of the base 501 and the cover member 555 face each other. The anode-side sound absorbing member 570 extends in the Z direction and has approximately the same length as the anode 500 , but may be shorter than the anode 500 . The structure and material of the anode-side sound absorbing member 570 are the same as those of the cathode-side sound absorbing member 470 .

[0152] 5.2 Function and effect

[0153] The sound wave 61a also propagates from the discharge space between the cathode 400 and the anode 500 to the gap 50 between the anode 500 and the anode side cover 550. In this structure, an anode-side sound-absorbing component 570 is also provided in the gap 50, so that the sound wave 61a propagating to the gap 50 is absorbed by the anode-side sound-absorbing component 570 provided in the gap 50 and can be gradually attenuated. Therefore, the size of the reflected wave 61b reflected inside the anode-side sound-absorbing component 570 and returned to the discharge space is reduced, and the change in the density distribution of the laser gas in the discharge space caused by the reflected wave 61b can be suppressed, and the main discharge can be suppressed from becoming unstable. As a result, the reduction in the stability of the energy of the laser emitted from the gas laser device 100 can be suppressed. Figure 16 In the figure, the reflected wave 61b is omitted for ease of observation.

[0154] Furthermore, in the chamber 131 of the present embodiment, the anode-side sound absorbing member 570 is disposed on each of the anode-side cover 550 and the anode 500 .

[0155] With this configuration, compared to a case where the anode-side sound absorbing member 570 is disposed on only one of the anode 500 and the anode-side cover 550, the sound wave 61a is absorbed by the anode-side sound absorbing member 570 and can be further attenuated. Consequently, the magnitude of the reflected wave 61b is further reduced, further suppressing a decrease in the energy stability of the laser light emitted from the gas laser device 100.

[0156] In the chamber 131 of this embodiment, the anode-side sound absorbing member 570 is disposed on both the anode-side cover 550 and the anode 500. However, it may be disposed on either the anode-side cover 550 or the anode 500. Furthermore, the side surfaces of the base 501 are not disposed inwardly relative to the side surfaces of the discharge portion 503 but are disposed on the same plane. In other words, the anode 500 may have the same structure as the anode 500 of the comparative example, and the anode-side sound absorbing member 570 may also be disposed on the side surfaces of the anode 500.

[0157] 6. Description of the Chamber in Embodiment 4

[0158] Next, the chamber 131 of Embodiment 4 will be described. Components identical to those described above are denoted by the same reference numerals, and duplicate descriptions will be omitted unless otherwise specified. In some drawings, for ease of illustration, portions of components may be omitted or simplified. For identical components, only some reference numerals may be assigned, while others may be omitted.

[0159] 6.1 Structure

[0160] Figure 17 1 is a VH cross-sectional view of the periphery of anode 500 in this embodiment. In cavity 131 of this embodiment, groove 137b is provided in ground plate 137, and anode-side sound absorbing member 570 is disposed in groove 137b, which is different from Embodiment 1.

[0161] Groove 137b is provided on the upstream side of anode 500, specifically, between cover members 551 and 553 and below dielectric tube 11 and outer electrode 15. Groove 137b extends in the Z direction, and its depth in the V direction is constant in the Z direction.

[0162] The height of the anode-side sound absorbing member 570 disposed in the aforementioned groove 137 b in the V direction is constant in the Z direction, and the anode-side sound absorbing member 570 faces the dielectric tube 11 and the external electrode 15. The anode-side sound absorbing member 570 does not protrude from the main surface of the ground plate 137, and the surface 570 a of the anode-side sound absorbing member 570 facing the dielectric tube 11 and the external electrode 15 is located at the same height as the main surface of the ground plate 137.

[0163] Figure 18 This is a perspective view of the outer electrode 15 of the preionization electrode 10 of this embodiment. The outer electrode 15 includes a trapezoidal portion 15c, which is composed of an end portion 15a extending in the Z direction, i.e., the longitudinal direction of the dielectric tube 11, and in contact with the outer peripheral surface of the dielectric tube 11, and a plurality of rod members 15b connected at one end to the end portion 15a and arranged in parallel along the longitudinal direction of the end portion 15a. Due to the gaps 15e between the plurality of rod members 15b, the outer electrode 15 does not separate the discharge space from the anode-side sound absorbing member 570, as shown in FIG. Figure 17 As shown, the sound wave 61a propagates from the discharge space to the anode-side sound absorbing member 570 via the gap 15e.

[0164] 6.2 Action and Effect

[0165] Acoustic wave 61a also propagates from the discharge space between cathode 400 and anode 500 through gaps 15e between the plurality of rod members 15b to ground plate 137. In this configuration, anode-side sound absorbing members 570 are disposed within grooves 137b of ground plate 137, allowing acoustic wave 61a to be absorbed by anode-side sound absorbing members 570. Consequently, the magnitude of reflected wave 61b returning from anode-side sound absorbing members 570 and grooves 137b to the discharge space is reduced, suppressing changes in the laser gas density distribution within the discharge space caused by reflected wave 61b and preventing instability in the main discharge. This reduces the stability of the laser energy emitted from gas laser device 100. Furthermore, since anode-side sound absorbing members 570 are disposed within grooves 137b, they are less likely to obstruct the flow of laser gas within chamber 131, compared to a case where anode-side sound absorbing members 570 are disposed on the main surface of ground plate 137.

[0166] In addition, the structures of the groove 137b and the anode-side sound absorbing member 570 are not necessarily limited to those described above, and other examples will be described using modified examples.

[0167] Figure 19 : is a VZ cross-sectional view of the groove 137b of the modification 1 of this embodiment. Figure 19 In the figure, for ease of viewing, illustration of components other than the ground plate 137, the groove 137b, and the anode-side sound absorbing member 570 is omitted. Figure 20 yes Figure 19A cross-sectional view of the periphery of the groove 137b at line EE shown, Figure 21 yes Figure 19 FF line shown in FIG. Figure 19 The cross-sectional view of the periphery of the groove 137b at the DD line shown is the same as that of the Figure 17 same.

[0168] In this modified example, the depth of groove 137b in the V direction, which is perpendicular to the main surface of ground plate 137, gradually increases from one side in the Z direction to the other. This is different from the embodiment in that the main surface of ground plate 137 is perpendicular to the Z direction. Therefore, the bottom surface of groove 137b is inclined from one side in the Z direction to the other. One side in the Z direction is located on the monitoring module 160 side, and the other side is located on the narrowband module 145 side.

[0169] Furthermore, the anode-side sound absorbing member 570 of this modified example is disposed on the inclined bottom surface of the groove 137b as described above. Similar to the fourth embodiment, the height of the anode-side sound absorbing member 570 in the V direction is constant from one side to the other in the Z direction. Therefore, similar to the fourth embodiment, at the position on line DD, the anode-side sound absorbing member 570 does not protrude from the main surface of the ground plate 137, and the surface 570a of the anode-side sound absorbing member 570 is located at the same height as the main surface of the ground plate 137. Furthermore, the position of the surface 570a on line EE is lower than the main surface of the ground plate 137, and the position on line FF is lower than the main surface of the ground plate 137.

[0170] In the groove 137b of this modification, the depth of the groove 137b in the V direction perpendicular to the main surface of the ground plate 137 orthogonal to the Z direction as the prescribed direction increases from one side toward the other side.

[0171] With this structure, the distance from the other side of the bottom surface of slot 137b in the predetermined direction to the discharge space is longer than the distance from the one side of the bottom surface in the predetermined direction to the discharge space. Consequently, the phase of reflected wave 61b returning to the discharge space from the other side of the bottom surface in the predetermined direction is offset from the phase of reflected wave 61b returning to the discharge space from the one side of the bottom surface in the predetermined direction. This phase offset can prevent reflected waves 61b from returning to the discharge space all at once, compared to a situation where the phases are not offset. Consequently, changes in the laser gas density distribution in the discharge space caused by reflected wave 61b can be suppressed, thereby preventing unstable main discharge.

[0172] Figure 22 : is a VZ cross-sectional view of the groove 137b of the second modification of this embodiment. Figure 22In the figure, for ease of viewing, illustration of components other than the ground plate 137, the groove 137b, and the anode-side sound absorbing member 570 is omitted.

[0173] The anode-side sound absorbing member 570 of this modification differs from Modification 1 in that its height in the V direction gradually increases from one side in the Z direction to the other. The surface 570a of the anode-side sound absorbing member 570 is located at the same height from one side in the Z direction to the other, and is located at the same height as the main surface of the ground plate 137.

[0174] With this configuration, sound wave 61a absorbed by anode-side sound absorbing member 570 is repeatedly reflected and attenuated more frequently on the other side in the Z direction than on the one side in the Z direction. Consequently, reflected wave 61b returning to the discharge space from the other side in the predetermined direction is reduced compared to reflected wave 61b returning to the discharge space from the one side in the predetermined direction. This reduces the change in the density distribution of the laser gas in the discharge space caused by reflected wave 61b, compared to a case where this change is not reduced. This allows for the suppression of unstable main discharge.

[0175] In the chamber 131 of each modified example of the present embodiment, one side in the Z direction is described as the monitoring module 160 side and the other side is described as the narrowing module 145 side, but the reverse may be true.

[0176] In Modification 2, the anode-side sound absorbing member 570 does not need to gradually increase in height in the V direction from one side in the Z direction to the other side. Alternatively, the anode-side sound absorbing member 570 may increase in height in a stepwise manner from one side in the Z direction to the other side. Furthermore, the anode-side sound absorbing member 570 of this embodiment and the various modifications may be disposed on the main surface of the grounding plate 137, rather than in the groove 137b of the grounding plate 137.

[0177] 7. Description of the Chamber of Embodiment 5

[0178] Next, the chamber 131 of Embodiment 5 will be described. The same reference numerals are used to designate the same components as those described above, and duplicate descriptions will be omitted unless otherwise specified. In some drawings, for ease of illustration, portions of components may be omitted or simplified. For identical components, only some reference numerals may be used, while others may be omitted.

[0179] 7.1 Structure

[0180] Figure 23This is a top view of the periphery of the anode 500 in this embodiment. In the chamber 131 of this embodiment, in order to suppress the influence of the acoustic wave 61a on the performance of the laser, when viewed along the V direction, the longitudinal directions of the dielectric tube 11 and the external electrode 15 are inclined relative to the virtual axis 70 described later, which is different from the first embodiment. Figure 23 In the figure, to facilitate understanding of this tilt, the center axis 11a of the dielectric tube 11 is shown tilted relative to the imaginary axis 70 as an example. The imaginary axis 70 extends in the Z direction between the cathode 400 and the anode 500. Furthermore, the imaginary axis 70 is located between the cathode 400 and the anode 500 and overlaps with the center axis of the anode 500 when viewed along the V direction. Due to this tilt, the distance from the imaginary axis 70 to the dielectric tube 11 decreases from one side in the Z direction to the other. The one side in the Z direction is located on the monitoring module 160 side, and the other side is located on the narrowing module 145 side. While the dielectric tube 11 is used in the above description, the same applies to the inner electrode 13, the outer electrode 15, the end portion 15a, the portion of the cover member 551 with which the dielectric tube 11 contacts, and the cover member 553.

[0181] 7.2 Action and Effect

[0182] By shortening the distance as described above, the propagation path length of reflected wave 61b from dielectric tube 11, returning from dielectric tube 11 to the discharge space, changes depending on the position in a predetermined direction. Consequently, compared to situations where reflected wave 61b returning to the discharge space experiences a phase shift or no phase shift, it is possible to suppress the simultaneous return of reflected waves 61b to the discharge space. Consequently, changes in the laser gas density distribution in the discharge space caused by reflected wave 61b can be suppressed, thereby preventing unstable main discharge.

[0183] Furthermore, the ground plate 137 of the present embodiment may be provided with the groove 137 b and the anode-side sound absorbing member 570 described in the fourth embodiment and its modified example.

[0184] Next, a modification of this embodiment will be described. Figure 24 This is a top view of the periphery of anode 500 in this variation. In this variation, the longitudinal directions of dielectric tube 11, external electrode 15, the portion of cover member 551 where dielectric tube 11 contacts, and cover member 553 are inclined relative to imaginary axis 70, similar to Embodiment 5. Ground plate 137 in this variation is provided with groove 137b and anode-side sound absorbing member 570, as described in Embodiment 4. Grooves 137b and anode-side sound absorbing member 570 in this variation will be described later.

[0185] Figure 25 yes Figure 24A cross-sectional view of the periphery of the groove 137b at line GG shown in FIG. Figure 26 yes Figure 24 The cross-sectional view of the periphery of the groove 137b at the HH line shown, Figure 27 yes Figure 24 A cross-sectional view of the periphery of the groove 137b taken along line II is shown.

[0186] In the groove 137b and the anode-side sound absorbing member 570 of this modification, the longitudinal direction of each groove 137b and the anode-side sound absorbing member 570 is inclined relative to the imaginary axis 70, similarly to the dielectric tube 11, which is different from the fourth embodiment. Therefore, the anode-side sound absorbing member 570 and the groove 137b are arranged along the dielectric tube 11, and the distance from the imaginary axis 70 to the anode-side sound absorbing member 570 decreases from one side to the other side in the Z direction. Figure 24 In FIG, the portion of the anode-side sound absorbing member 570 that overlaps with the dielectric tube 11 is indicated by a dotted line. Figure 26 In order to Figure 25 For comparison, the dashed line Figure 25 The dielectric tube 11, the inner electrode 13 and the anode side sound absorbing member 570 are shown. Figure 27 In order to Figure 26 For comparison, the dashed line Figure 26 The dielectric tube 11, the inner electrode 13 and the anode side sound absorbing component 570 are shown. Figure 25 、 Figure 26 and Figure 27 , it can be understood that the dielectric tube 11 , the inner electrode 13 , and the anode-side sound absorbing member 570 are approaching the imaginary axis 70 from one side toward the other side in the Z direction.

[0187] With this configuration, the propagation path length of reflected wave 61b from anode-side sound absorbing member 570, returning from anode-side sound absorbing member 570 to the discharge space, varies depending on the position in a predetermined direction. Consequently, it is possible to suppress the simultaneous return of reflected waves 61b to the discharge space, compared to situations where the phases of reflected waves 61b returning to the discharge space are shifted or not. Consequently, changes in the laser gas density distribution in the discharge space caused by reflected waves 61b can be suppressed, thereby preventing unstable main discharge.

[0188] In the present variation, the chamber 131 is described using the grooves 137b whose depth in the V direction is constant in the Z direction and the anode-side sound absorbing member 570 whose height in the V direction is constant in the Z direction, as described in the fourth embodiment. However, the grooves 137b and anode-side sound absorbing member 570 of this variation only need to be inclined relative to the imaginary axis 70 as described above. The grooves 137b and anode-side sound absorbing member 570 described in the first and second variations of the fourth embodiment may also be used. Furthermore, the anode-side sound absorbing member 570 of this variation may be disposed on the main surface of the grounding plate 137, rather than in the grooves 137b of the grounding plate 137. Furthermore, the preionization electrode 10 of this variation does not need to be inclined relative to the imaginary axis 70 as in the present embodiment. Furthermore, in the present embodiment and the present variation, the chamber 131 is described with one side in the Z direction being the monitoring module 160 side and the other side being the narrowband module 145 side. However, the reverse is also possible.

[0189] The above description is not limiting but merely illustrative. Therefore, it is obvious to those skilled in the art that changes can be made to the embodiments of the present disclosure without departing from the scope of the claims. In addition, it is 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", "having", and "having" should be interpreted as "not excluding the presence of constituent elements other than the recorded constituent elements". In addition, the modifier "1" should be interpreted as "at least 1" or "1 or more". In addition, terms such as "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 also be interpreted as including combinations of them with contents other than "A", "B" and "C".

Claims

1. A chamber of a gas laser device, wherein a laser gas is sealed in an internal space of the chamber, wherein: The chamber has: an anode, which is disposed in the internal space and has a length direction along a predetermined direction; a cathode disposed in the internal space, comprising a base and a discharge portion protruding from the base toward the anode, wherein the cathode has a length direction along the predetermined direction and is separated from and opposite to the anode; a cathode side cover, which is arranged in the internal space, separated from a part of the base and the discharge part, and covers the base; as well as A cathode side sound absorbing member is provided in a gap between a portion of the base and the cathode side cover.

2. The chamber of the gas laser device according to claim 1, wherein: The cathode-side sound absorbing member is disposed on the base.

3. The chamber of the gas laser device according to claim 1, wherein: The cathode side sound absorbing member is disposed on the cathode side cover.

4. The chamber of the gas laser device according to claim 1, wherein: The cathode side sound absorbing component is respectively disposed on the base and the cathode side cover.

5. The chamber of the gas laser device according to claim 4, wherein: The cathode side sound absorbing member disposed on the base faces the cathode side sound absorbing member disposed on the cathode side cover.

6. The chamber of the gas laser device according to claim 1, wherein: The cathode-side sound absorbing member is further arranged at a position in the gap farthest from a discharge space between the cathode and the anode.

7. The chamber of the gas laser device according to claim 1, wherein: A surface of the cathode side cover in contact with the gap is perpendicular to a direction from the anode toward the cathode, extends in the predetermined direction, and is inclined from one side toward the other side in the predetermined direction so as to be away from the anode.

8. The chamber of the gas laser device according to claim 7, wherein: The cathode side sound absorbing member extends along the predetermined direction and is arranged on the base. The height of the cathode-side sound absorbing member in a direction from the anode toward the cathode increases from one side toward the other side in the predetermined direction.

9. The chamber of the gas laser device according to claim 1, wherein: The chamber of the gas laser device further comprises: a grounding plate disposed in the internal space, and the anode is disposed on the grounding plate; an anode side cover, which is disposed on the ground plate, separated from the anode on the side of the anode and covers the anode; as well as The anode side sound absorbing component is arranged in the gap between the anode side cover and the anode.

10. The chamber of the gas laser device according to claim 9, wherein: The anode side sound absorbing member is disposed on the anode side cover.

11. The chamber of the gas laser device according to claim 9, wherein: The anode-side sound absorbing member is disposed on the anode.

12. The chamber of the gas laser device according to claim 9, wherein: The anode side sound absorbing member is respectively disposed on the anode side cover and the anode.

13. The chamber of the gas laser device according to claim 1, wherein: The chamber of the gas laser device further comprises: a grounding plate disposed in the internal space, wherein the anode is disposed on the grounding plate; and The anode-side sound absorbing member is disposed on the ground plate and is disposed in a groove provided on the side of the anode.

14. The chamber of the gas laser device according to claim 13, wherein: The groove extends along the specified direction, The depth of the groove in a direction perpendicular to a main surface of the ground plate increases from one side toward the other side in the prescribed direction, wherein the main surface of the ground plate is orthogonal to the prescribed direction.

15. The chamber of the gas laser device according to claim 14, wherein: The anode side sound absorbing member extends along the prescribed direction, The height of the anode-side sound absorbing member in the vertical direction is constant from one side toward the other side in the predetermined direction.

16. The chamber of the gas laser device according to claim 14, wherein: The anode side sound absorbing member extends along the prescribed direction, The height of the anode-side sound absorbing member in the vertical direction increases from one side toward the other side in the prescribed direction.

17. The chamber of the gas laser device according to claim 1, wherein: The chamber of the gas laser device further comprises a pre-ionization electrode disposed on the side of the anode. The preionization electrode comprises: a dielectric tube; a preionization inner electrode, which is arranged inside the dielectric tube and extends along the length direction of the dielectric tube; and a preionization outer electrode, which extends along the length direction of the dielectric tube and includes an end portion opposite to the dielectric tube. A distance from an imaginary axis to the dielectric tube becomes shorter from one side toward the other side in the prescribed direction, wherein the imaginary axis extends between the cathode and the anode along the prescribed direction.

18. The chamber of the gas laser device according to claim 17, wherein: The chamber of the gas laser device further comprises: a grounding plate disposed in the internal space, wherein the anode is disposed on the grounding plate; and an anode-side sound absorbing member disposed on the side of the anode in the ground plate, The distance from the virtual axis to the anode-side sound absorbing member becomes shorter from one side toward the other side in the predetermined direction.

19. A gas laser device comprising a chamber in which a laser gas is sealed in an internal space, wherein: The chamber has: an anode, which is disposed in the internal space and has a length direction along a predetermined direction; a cathode disposed in the internal space, comprising a base and a discharge portion protruding from the base toward the anode, wherein the cathode has a length direction along the predetermined direction and is separated from and opposite to the anode; a cathode side cover, which is arranged in the internal space, separated from a part of the base and the discharge part, and covers the base; as well as A cathode side sound absorbing member is provided in a gap between a portion of the base and the cathode side cover.

20. A method for manufacturing an electronic device, wherein: The manufacturing method comprises the following steps: Generating laser light using a gas laser device having a chamber; outputting the laser light to an exposure device; and exposing the laser on a photosensitive substrate in the exposure device to manufacture an electronic device, The chamber is a chamber in which laser gas is sealed in an internal space, and the chamber comprises: an anode, which is disposed in the internal space and has a length direction along a predetermined direction; a cathode disposed in the internal space, comprising a base and a discharge portion protruding from the base toward the anode, wherein the cathode has a length direction along the predetermined direction and is separated from and opposite to the anode; a cathode side cover, which is arranged in the internal space, separated from a part of the base and the discharge part, and covers the base; as well as A cathode side sound absorbing member is provided in a gap between a portion of the base and the cathode side cover.

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