Discharge chamber for gas laser device and method for manufacturing electronic device

Abstract

A discharge chamber for a gas laser device in which a pair of discharge electrodes facing each other with a gap therebetween is disposed in an internal space and in which a laser gas is sealed, the discharge chamber being provided with: a first chamber member and a second chamber member that surround at least a part of the internal space by being combined with each other; and a metal seal that includes a linear portion and a curved portion, is disposed between the first cavity member and the second cavity member, and seals a gap between the first cavity member and the second cavity member by being pressed by the first cavity member and the second cavity member. The spring constant of the curved portion of the metal seal in the pressing direction when viewed to be linear is smaller than the spring constant of the linear portion in the pressing direction.

Description

Technical Field

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

[0002] In recent years, in semiconductor exposure devices, with the miniaturization and high integration of semiconductor integrated circuits, an improvement in resolution has been required. Therefore, the shortening of the wavelength of light emitted from an exposure light source has been promoted. For example, as a gas laser device for exposure, a KrF excimer laser device that emits laser light with an output wavelength of about 248 nm and an ArF excimer laser device that emits laser light with an output wavelength of about 193 nm are used.

[0003] The spectral line widths of the spontaneous oscillation light of KrF excimer laser devices and ArF excimer laser devices are wide, being 350 pm to 400 pm. Therefore, when a projection lens is made of a material that transmits ultraviolet light 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 such an extent that chromatic aberration can be ignored. Therefore, in the laser resonator of the gas laser device, in order to narrow the spectral line width, a narrowing module (Line Narrowing Module: LNM) including a narrowing element (etalon, grating, etc.) may be provided. Hereinafter, a gas laser device with a narrowed spectral line width will be referred to as a narrowed gas laser device.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-141941

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2016-75307 Summary of the Invention

[0008] A discharge chamber for a gas laser device according to one aspect of the present disclosure may have a pair of discharge electrodes disposed in an internal space so as to face each other with a space therebetween, and a laser gas sealed therein. The discharge chamber for the gas laser device includes: a first chamber member and a second chamber member that surround at least a part of the internal space by being combined with each other; and a metal seal including a straight portion and a bent portion, disposed between the first chamber member and the second chamber member, and pressed by the first chamber member and the second chamber member to seal a gap between the first chamber member and the second chamber member. The spring constant of the bent portion of the metal seal in the pressing direction when regarded as linear is smaller than the spring constant of the straight portion in the pressing direction.

[0009] A method for manufacturing an electronic device according to one aspect of the present disclosure can generate laser light by a gas laser device including a discharge chamber for a gas laser device, output the laser light to an exposure device, and expose the laser light onto a photosensitive substrate in the exposure device to manufacture an electronic device. The discharge chamber for the gas laser device has a pair of discharge electrodes disposed in an internal space with a gap therebetween and filled with a laser gas. The discharge chamber for the gas laser device includes: a first chamber member and a second chamber member that surround at least a part of the internal space by being combined with each other; and a metal seal including a straight portion and a bent portion. The metal seal is disposed between the first chamber member and the second chamber member and is pressed by the first chamber member and the second chamber member to seal a gap between the first chamber member and the second chamber member. A spring constant of the bent portion of the metal seal in a pressing direction when regarded as linear is smaller than a spring constant of the straight portion in the pressing direction. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0011] Figure 1 It is a schematic view showing a schematic configuration example of an entire manufacturing apparatus for an electronic device.

[0012] Figure 2 It is a schematic view showing a schematic configuration example of an entire gas laser device of a comparative example.

[0013] Figure 3 It is a cross-sectional view perpendicular to a traveling direction of laser light of a chamber device of a comparative example.

[0014] Figure 4 It is a view of a lower chamber as viewed from above.

[0015] Figure 5 It is a view of an upper chamber as viewed from above.

[0016] Figure 6 It is a view showing a cross-sectional view perpendicular to a length direction of a metal seal.

[0017] Figure 7 It is a view showing a cross-sectional view along a length direction of a metal seal.

[0018] Figure 8 It is a cross-sectional view along a length direction of a metal seal used for a discharge chamber for a gas laser device of Embodiment 1.

[0019] Figure 9 It is a cross-sectional view along a length direction in a first modification example of a metal seal.

[0020] Figure 10It is a longitudinal sectional view in the second modification example of the metal seal.

[0021] Figure 11 It is a longitudinal sectional view in the third modification example of the metal seal.

[0022] Figure 12 It is a longitudinal sectional view of the metal seal used for the discharge chamber of the gas laser device according to Embodiment 2.

[0023] Figure 13 It is a diagram showing another modification example of the metal seal. Detailed implementation manners

[0024] 1. Description of the manufacturing apparatus of an electronic device used in the exposure process of the electronic device

[0025] 2. Description of the comparative example

[0026] 2.1 Structure

[0027] 2.2 Operation

[0028] 2.3 Problem

[0029] 3. Description of Embodiment 1

[0030] 3.1 Structure

[0031] 3.2 Function and effect

[0032] 4. Description of Embodiment 2

[0033] 4.1 Structure

[0034] 4.2 Function and effect

[0035] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the 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 operations described in each embodiment are not necessarily all essential as the structures and operations of the present disclosure. Furthermore, the same reference numerals are assigned to the same components, and repeated descriptions are omitted.

[0036] 1. Description of the manufacturing apparatus of an electronic device used in the exposure process of the electronic device

[0037] Figure 1 It is a schematic diagram showing a schematic overall structure example of the manufacturing apparatus of an electronic device used in the exposure process of the electronic device. As Figure 1As shown, the manufacturing apparatus used in the exposure process includes a gas laser apparatus 100 and an exposure apparatus 200. The exposure apparatus 200 includes an illumination optical system 210 and a projection optical system 220. The illumination optical system 210 includes a plurality of mirrors 211, 212, and 213. The illumination optical system 210 illuminates the mask pattern on the mask stage RT with the laser incident from the gas laser apparatus 100. The projection optical system 220 reduces and projects the laser that has passed through the mask, and images it on an unillustrated workpiece disposed on the workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a photoresist. The exposure apparatus 200 synchronously and parallelly moves the mask stage RT and the workpiece stage WT, thereby exposing the laser reflecting the mask pattern onto the workpiece. By transferring the device pattern onto the semiconductor wafer through the exposure process as described above, a semiconductor device as an electronic device can be manufactured.

[0038] 2. Description of Comparative Example

[0039] 2.1 Structure

[0040] The gas laser apparatus 100 of the comparative example will be described. It should be noted that the comparative example of the present disclosure is a manner known only to the applicant, and is not a publicly known example recognized by the applicant himself.

[0041] Figure 2 is a schematic diagram showing a schematic overall structure example of the gas laser apparatus 100 of the comparative example. The gas laser apparatus 100 is, for example, an ArF excimer laser apparatus using a mixed gas containing argon (Ar), fluorine (F2), and neon (Ne). The gas laser apparatus 100 emits a laser having a center wavelength of approximately 193 nm. In addition, the gas laser apparatus 100 may also be a gas laser apparatus other than the ArF excimer laser apparatus. For example, it may also be a KrF excimer laser apparatus using a mixed gas containing krypton (Kr), F2, and Ne. In this case, the gas laser apparatus 100 emits a laser having a center wavelength of approximately 248 nm. A mixed gas containing Ar, F2, and Ne as a laser medium, and a mixed gas containing Kr, F2, and Ne as a laser medium are sometimes referred to as laser gas.

[0042] As Figure 2 shown, the gas laser apparatus 100 includes a housing 110, a laser oscillator 130 disposed in the internal space of the housing 110, a monitor module 160, a shutter 170, and a laser processor 190 as main structures. In Figure 2 it shows the internal structure of the cavity device 101 at a cross-section along the traveling direction of the laser. In the following description, sometimes the left side of the paper surface is referred to as the front side, the right side of the paper surface is referred to as the rear side, the upper side of the paper surface is referred to as the upper side, and the lower side of the paper surface is referred to as the lower side along the traveling direction of the laser.

[0043] The laser oscillator 130 includes a cavity device 101, a charger 141, a narrowbanding module 145, an output coupling mirror 147, and a pulse compression circuit 150 as main structures.

[0044] Figure 3 It is a cross-sectional view of the cavity device 101 perpendicular to the traveling direction of the laser. The cavity device 101 includes a discharge cavity 131, and the discharge cavity 131 surrounds an internal space where light is generated by passing through a laser medium in a laser gas excited by discharge described later. The discharge cavity 131 is a discharge cavity for a gas laser device. As Figure 2 , Figure 3 shown, the discharge cavity 131 of the cavity device 101 in this example includes a cavity main body 131M divided into an upper cavity 131a and a lower cavity 131b, and an electrically insulating plate 135 as a cover body. The upper cavity 131a is a member having an opening 131H formed on its upper surface, and constitutes at least a part of the upper side of the discharge cavity 131. The lower cavity 131b is a bottomed member, and constitutes at least a part of the lower side of the discharge cavity 131. The lower edge portion of the upper cavity 131a and the upper edge portion of the lower cavity 131b face each other, and the upper cavity 131a and the lower cavity 131b are combined. By combining the upper cavity 131a and the lower cavity 131b in this way, the upper cavity 131a and the lower cavity 131b surround at least a part of the internal space of the discharge cavity 131. As materials for the upper cavity 131a and the lower cavity 131b, for example, metals such as aluminum plated with nickel or stainless steel plated with nickel can be cited.

[0045] Figure 4 It is a view of the lower cavity 131b observed from above. As Figure 4As shown, the cross-section of the internal space of the discharge chamber 131 in the horizontal direction is of a substantially rectangular shape. That is, the upper edge portion of the lower chamber 131b surrounds a substantially rectangular opening. A groove 132b is formed in the upper edge portion of the lower chamber 131b, and a metal seal 310b is disposed in the groove 132b. Therefore, the metal seal 310b is also of a substantially rectangular shape, including a straight portion 351b and a bent portion 352b. In this example, the shape of the metal seal 310b is substantially rectangular. The length of the straight portion 351b of the long side in the rectangle is, for example, approximately 800 mm, and the length of the straight portion 351b of the short side is, for example, approximately 300 mm. Additionally, the length of the bent portion 352b is, for example, approximately 50 mm. The upper chamber 131a and the lower chamber 131b are fixed in such a manner that they are pressed against each other by components not shown. Due to this pressing force, the metal seal 310b is deformed in a flattened manner in the pressing direction, sealing the gap between the upper chamber 131a and the lower chamber 131b. Here, if the upper chamber 131a and the lower chamber 131b are considered as the first chamber component and the second chamber component, respectively, the first chamber component and the second chamber component surround at least a part of the internal space of the discharge chamber 131 by being combined with each other, and the metal seal 310b seals the gap between the first chamber component and the second chamber component. Details of the metal seal 310b will be described later.

[0046] The laser gas in the internal space of the discharge chamber 131 is supplied from a laser gas supply source (not shown) through a pipe (not shown). Additionally, the laser gas in the discharge chamber 131 is subjected to a process of removing F2 gas by a halogen filter, etc., and is exhausted to the housing 110 by an exhaust pump (not shown) through a pipe (not shown).

[0047] The opening 131H in the upper chamber 131a of the chamber body 131M is blocked by an insulating plate 135. In this way, the chamber body 131M and the insulating plate 135 surround at least a part of the internal space of the discharge chamber 131 by being combined with each other.

[0048] Figure 5This is a view of the upper chamber 131a from the upper side. The opening 131H has a substantially rectangular shape. A groove 132a surrounding the opening 131H is formed on the upper surface of the upper chamber 131a, and a metal seal 310a is disposed within the groove 132a. Accordingly, the metal seal 310a also has a substantially rectangular shape, including a straight portion 351a and a bent portion 352a. In this example, the shape of the metal seal 310a is substantially rectangular. The length of the straight portion 351a of the long side in the rectangle is, for example, approximately 780 mm, and the length of the straight portion 351a of the short side is, for example, approximately 300 mm. Additionally, the length of the bent portion 352a is, for example, approximately 80 mm. The chamber body 131M and the electrical insulating plate 135 are fixed in such a manner that they are pressed against each other by components not shown. By this pressing force, the metal seal 310a is deformed in a flattened manner in the pressing direction, sealing the gap between the chamber body 131M and the electrical insulating plate 135. Here, if the chamber body 131M and the electrical insulating plate 135 are defined as the first chamber component and the second chamber component, respectively, the first chamber component and the second chamber component surround at least a part of the internal space of the discharge chamber 131 when combined with each other, and the metal seal 310a seals the gap between the first chamber component and the second chamber component. Details of the metal seal 310a will be described later.

[0049] The electrical insulating plate 135 includes an insulator. As a material for the electrical insulating plate 135, for example, alumina ceramics with low reactivity to F2 gas can be cited. In addition, as long as the electrical insulating plate 135 has electrical insulation properties, materials such as phenolic resin, fluororesin, etc. resins, or quartz, glass, etc. can be cited as materials for such an electrical insulating plate 135.

[0050] In the internal space of the discharge chamber 131, the electrode 134a as the first main electrode and the electrode 134b as the second main electrode are opposed to each other with a space therebetween, and their respective longitudinal directions are arranged along a specified direction that is the traveling direction of the laser. In this example, the electrode 134b is located directly above the electrode 134a. The electrodes 134a and 134b are discharge electrodes for exciting the laser medium through glow discharge. In this example, the electrode 134a is the anode and the electrode 134b is the cathode.

[0051] The electrode holder 137 is electrically connected to the chamber body 131M via the wiring 137a. The electrode 134a is supported by the electrode holder 137 and is electrically connected to the electrode holder 137. The electrode 134a is electrically connected to the ground wire via the electrode holder 137, the wiring 137a, and the chamber body 131M. The electrode 134b is fixed, for example, to the surface of the electrical insulating plate 135 on the side of the internal space of the discharge chamber 131 by a current introduction terminal 157 formed of a bolt. The current introduction terminal 157 is electrically connected to a pulse compression circuit 150 and other circuit components described later, ensuring conduction between the pulse compression circuit 150 and the electrode 134b.

[0052] The charger 141 is a DC high-voltage power supply that supplies electric energy to the pulse compression circuit 150. The switch 151 is electrically connected to the charger 141 and is controlled by the laser processor 190. It is configured such that when the switch 151 changes from off to on, the electric energy from the charger 141 is supplied to the pulse compression circuit 150. The pulse compression circuit 150 is arranged on the cage 155, generates a pulsed high voltage using the electric energy held in the charger 141, and applies this high voltage between the electrode 134a and the electrode 134b.

[0053] When a high voltage is applied between the electrode 134a and the electrode 134b, a discharge occurs between the electrode 134a and the electrode 134b. The energy of this discharge excites the laser medium in the discharge chamber 131, and the excited laser medium emits light when it transitions to the ground state.

[0054] The circuit between the pulse compression circuit 150 and the electrode 134a mainly includes a plurality of peaking capacitors 153, a connection plate 152, and the above-mentioned current introduction terminal 157.

[0055] The connection plate 152 is a conductive plate that connects the electrode 134b and the pulse compression circuit 150, and is composed of a metal plate with a substantially U-shaped cross-section perpendicular to the length direction. One terminal of each peaking capacitor 153 is electrically connected to the connection plate 152. The peaking capacitor 153 is, for example, a ceramic capacitor with a dielectric material such as strontium titanate. In addition, other materials for the dielectric can include barium titanate, etc. The current introduction terminal 157 is electrically connected to the connection plate 152. In this way, one terminal of a plurality of peaking capacitors 153 is electrically connected to one electrode 134b.

[0056] The other terminal of each peaking capacitor 153 is electrically connected to the cage 155. The cage 155 is electrically connected to the discharge chamber 131. Therefore, the other terminal of each peaking capacitor 153 is electrically connected to the ground wire. In addition, the other terminal of each peaking capacitor 153 is electrically connected to the other electrode 134a via the cage 155.

[0057] A preionization electrode 180 is provided on the side of the electrode 134a on the electrode holding portion 137. The preionization electrode 180 includes a dielectric tube 181, a preionization inner electrode 183, and a preionization outer electrode 185.

[0058] The longitudinal direction of the dielectric tube 181 is arranged along a specified direction. The dielectric tube 181 is, for example, a cylindrical tube. The dielectric tube 181 is made of, for example, alumina ceramics or sapphire. The pre-ionization inner electrode 183 is rod-shaped and is arranged inside the dielectric tube 181, extending along the longitudinal direction of the dielectric tube 181. The pre-ionization inner electrode 183 is made of, for example, copper or brass. The pre-ionization outer electrode 185 is arranged between the dielectric tube 181 and the electrode 134a and extends along the longitudinal direction of the dielectric tube 181. The end portion of the pre-ionization outer electrode 185 is in contact with the outer peripheral surface of the dielectric tube 181. Further, as long as the corona discharge described later is generated, at least a part of the end portion of the pre-ionization outer electrode 185 may not be in contact with the outer peripheral surface of the dielectric tube 181. The pre-ionization outer electrode 185 is fixed to a spacer 187 fixed to the electrode 134a.

[0059] The pre-ionization inner electrode 183 is electrically connected to the pulse compression circuit 150 via a pre-ionization capacitor (not shown). The pre-ionization outer electrode 185 is electrically connected to the electrode 134a via the electrode holding portion 137, and is also electrically connected to the discharge chamber 131 via the electrode holding portion 137 and the wiring 137a. Therefore, the pre-ionization outer electrode 185 is electrically connected to the ground wire. By applying a high voltage from the pulse compression circuit 150 to the pre-ionization inner electrode 183 and the pre-ionization outer electrode 185, a corona discharge is generated near the end portion of the pre-ionization outer electrode 185. This corona discharge assists in the stable generation of the glow discharge generated between the electrodes 134a and 134b.

[0060] A cross-flow fan 149 and a heat exchanger 148 are arranged on the side opposite to the electrode 134a side with respect to the electrode holding portion 137 in the internal space of the discharge chamber 131. The space in the discharge chamber 131 where the cross-flow fan 149 and the heat exchanger 148 are arranged communicates with the space between the electrode 134a and the electrode 134b. The heat exchanger 148 is arranged beside the cross-flow fan 149 and is a radiator connected to a pipe (not shown) through which a cooling medium flows. As Figure 2 shown, the cross-flow fan 149 is connected to a motor 149a arranged outside the discharge chamber 131 and rotates by the rotation of the motor 149a. By the rotation of the cross-flow fan 149, the laser gas sealed in the internal space of the discharge chamber 131 circulates as shown by the arrow in Figure 3 . At least a part of the circulating laser gas passes through the heat exchanger 148, and the temperature of the laser gas is adjusted.

[0061] A pair of windows 139a and 139b are provided on the wall surface of the discharge chamber 131. The window 139a is located on one end side in the traveling direction of the laser in the discharge chamber 131, the window 139b is located on the other end side in the traveling direction, and the windows 139a and 139b are separated by the space between the electrodes 134a and 134b. The windows 139a and 139b are inclined at the Brewster angle with respect to the traveling direction of the laser to suppress the reflection of the laser. The laser oscillated as described later is emitted to the outside of the discharge chamber 131 through the windows 139a and 139b. As described above, a pulsed high voltage is applied between the electrodes 134a and 134b by the pulse compression circuit 150, so this laser is a pulsed laser.

[0062] The narrowbanding module 145 includes a housing 145a, a prism 145b, a grating 145c disposed in the internal space of the housing 145a, and a rotating table (not shown). An opening is formed in the housing 145a, and the housing 145a is connected to the rear side of the discharge chamber 131 through the opening.

[0063] The prism 145b expands the beam width of the light emitted from the window 139a and makes the light incident on the grating 145c. In addition, the prism 145b narrows the beam width of the reflected light from the grating 145c and makes the light return to the internal space of the discharge chamber 131 through the window 139a. The prism 145b is supported by the rotating table and rotates by the rotating table. By rotating the prism 145b, the incident angle of the light with respect to the grating 145c is changed, and the wavelength of the light returning from the grating 145c to the discharge chamber 131 through the prism 145b can be selected. In Figure 2 the example of arranging one prism 145b is shown, but at least one prism may be arranged.

[0064] The surface of the grating 145c is made of a material with a high reflectivity, and a plurality of grooves are provided at a predetermined interval on the surface. The cross-sectional shape of each groove is, for example, a right triangle. When the light incident on the grating 145c from the prism 145b is reflected by these grooves, it diffracts in the direction corresponding to the wavelength. The grating 145c is configured such that the incident angle of the light incident on the grating 145c from the prism 145b is consistent with the diffraction angle of the diffracted light of the desired wavelength. Thus, the light near the desired wavelength returns to the discharge chamber 131 through the prism 145b.

[0065] The output coupling mirror 147 is disposed in the internal space of the optical path tube 147a connected to the front side of the discharge chamber 131 and faces the window 139b. The output coupling mirror 147 allows a part of the laser emitted from the window 139b to pass through toward the monitor module 160 and reflects the other part back to the internal space of the discharge chamber 131 through the window 139b. In this way, the grating 145c and the output coupling mirror 147 constitute a Fabry - Perot type laser resonator.

[0066] The monitor module 160 is disposed on the optical path of the laser beam emitted from the output coupling mirror 147. The monitor module 160 includes a housing 161, a beam splitter 163 disposed in the internal space of the housing 161, and a light sensor 165. An opening is formed in the housing 161, and the internal space of the housing 161 communicates with the internal space of the optical path tube 147a through the opening.

[0067] The beam splitter 163 transmits a part of the laser beam emitted from the output coupling mirror 147 toward the shutter 170, and reflects the other part of the laser beam toward the light receiving surface of the light sensor 165. The light sensor 165 outputs a signal indicating the energy E of the laser beam incident on the light receiving surface to the laser processor 190.

[0068] The laser processor 190 of the present disclosure is a processing device, including a storage device 190a storing a control program and a CPU (Central Processing Unit) 190b executing the control program. The laser processor 190 is specially configured or programmed to execute various processes included in the present disclosure. In addition, the laser processor 190 controls the entire gas laser device 100.

[0069] Various signals are transmitted and received between the laser processor 190 and the exposure processor 230 of the exposure device 200. For example, the laser processor 190 receives signals such as a light emission trigger Tr and a target energy Et, which will be described later, from the exposure processor 230. The target energy Et is the target value of the energy of the laser beam used in the exposure process. The laser processor 190 controls the charging voltage of the charger 141 based on the energy E received from the light sensor 165 and the target energy Et received from the exposure processor 230. The energy of the laser beam is controlled by controlling the charging voltage. In addition, the laser processor 190 is electrically connected to the shutter 170 and controls the opening and closing of the shutter 170.

[0070] The laser processor 190 closes the shutter 170 until the difference ΔE between the energy E received from the monitor module 160 and the target energy Et received from the exposure processor 230 is within an allowable range. In addition, if the difference ΔE is within the allowable range, the laser processor 190 sends a reception ready completion signal notifying the completion of the reception preparation of the light emission trigger Tr to the exposure processor 230. When receiving the reception ready completion signal, the exposure processor 230 sends a signal indicating the light emission trigger Tr to the laser processor 190, and the laser processor 190 opens the shutter 170 when receiving the signal indicating the light emission trigger Tr. The light emission trigger Tr is a timing signal for the exposure processor 230 to cause the laser oscillator 130 to perform laser oscillation, and is an external trigger. The light emission trigger Tr may be specified by a prescribed repetition frequency f and a prescribed number of pulses P of the laser beam. The repetition frequency f of the laser beam is, for example, 100 Hz or more and 10 kHz or less.

[0071] The shutter 170 is disposed on the optical path within the internal space of the optical path tube 171, and the optical path tube communicates with an opening formed on the side of the housing 161 of the monitor module 160 opposite to the side to which the optical path tube 147a is connected. The internal spaces of the optical path tubes 171 and 147a, the housing 161, and the internal space of 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 through a pipe (not shown) from a purge gas supply source (not shown). Further, the optical path tube 171 communicates with the exposure apparatus 200 through an opening of the housing 110 and an optical path tube 500 that connects the housing 110 to the exposure apparatus 200. The laser light that has passed through the shutter 170 is incident on the exposure apparatus 200.

[0072] The exposure processor 230 of the present disclosure is a processing device, including a storage device that stores a control program and a CPU that executes the control program. The exposure processor 230 is specifically configured or programmed to execute various processes included in the present disclosure. Further, the exposure processor 230 controls the entire exposure apparatus 200.

[0073] Next, the structures of the metal seals 310b and 310a in this example will be described. Further, in this example, the metal seals 310b and 310a have substantially the same structure, and thus the metal seal 310a will be described.

[0074] Figure 6 is a view showing a cross-section of the metal seal 310a perpendicular to the length direction, Figure 7 is a view showing a cross-section of the metal seal 310a along the length direction. As Figure 6 、 Figure 7 shown, the metal seal 310a in this example includes a helical spring 320 and an outer skin 330. The helical spring 320 is a structure in which a metal wire is formed in a spiral shape at a predetermined pitch. The outer skin 330 is a member formed by processing a metal plate-like member into a shape having a substantially C-shaped cross-section perpendicular to the length direction. The outer skin 330 substantially surrounds the outer peripheral surface of the helical spring 320.

[0075] The metal seal 310a disposed in the groove 132a is pressed radially by the electrical insulation plate 135 and the cavity body 131M, and is deformed in a flattened manner in the pressing direction as described above to seal the gap between the cavity body 131M and the electrical insulation plate 135. Similarly, the metal seal 310b disposed in the groove 132b is pressed radially by the upper cavity 131a and the lower cavity 131b, and is deformed in a flattened manner in the pressing direction as described above to seal the gap between the upper cavity 131a and the lower cavity 131b.

[0076] 2.2 Operation

[0077] Next, the operation of the gas laser device 100 of the comparative example will be described.

[0078] In a state before the gas laser device 100 emits laser light, purge gas is filled into the internal spaces of the optical path tube 147a, 171, 500 and the internal spaces of the housings 145a, 161 from a purge gas supply source (not shown). In addition, laser gas is supplied into the internal space of the discharge chamber 131 from a laser gas supply source (not shown). When supplying the laser gas, the laser processor 190 controls the motor 149a to rotate the cross-flow fan 149. By the rotation of the cross-flow fan 149, the laser gas circulates in the internal space of the discharge chamber 131. At this time, the gap between the upper chamber 131a and the lower chamber 131b is sealed by the metal seal 310b, and the gap between the chamber main body 131M and the electrical insulating plate 135 is sealed by the metal seal 310a, so that the laser gas is prevented from leaking to the outside of the discharge chamber 131.

[0079] 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. When the laser processor 190 receives the signal indicating the target energy Et, it closes the shutter 170 and drives the charger 141. In addition, the laser processor 190 turns on the switch 151 of the pulse compression circuit 150. As a result, the current from the charger 141 charges the peaking capacitor 153 via the pulse compression circuit 150. At this time, the peaking capacitor 153 is charged to a high potential in a short time. Then, a pulsed high voltage is applied to the electrode 134b from the charger 141 and the peaking capacitor 153 via the current introduction terminal 157 in a short time. In addition, the timing of applying a high voltage between the preionization inner electrode 183 and the preionization outer electrode 185 is slightly earlier than the timing of applying a high voltage between the electrodes 134a and 134b. When a high voltage is applied between the preionization inner electrode 183 and the preionization outer electrode 185, a corona discharge occurs near the ends of the dielectric tube 181 and the preionization outer electrode 185, and ultraviolet light is emitted. When the ultraviolet light irradiates the laser gas between the electrodes 134a and 134b, the laser gas between the electrodes 134a and 134b is preionized. After preionization, when a high voltage is applied between the electrodes 134a and 134b as described above, a main discharge occurs between the electrodes 134a and 134b.

[0080] Through this main discharge, the laser medium contained in the laser gas between the electrodes 134a and 134b becomes an excited state, and light is emitted when the laser medium returns to the ground state. Through this light, the light resonates between the grating 145c and the output coupler 147, and the light is amplified each time it passes through the discharge space in the internal space of the discharge chamber 131, generating laser oscillation. A part of the resonating laser passes through the output coupler 147 as pulsed laser light and travels toward the beam splitter 163.

[0081] A part of the laser light that travels to the beam splitter 163 is reflected by the beam splitter 163 and received by the light sensor 165. The light sensor 165 measures the energy E of the received laser light and outputs a signal representing the energy E to the laser processor 190. The laser processor 190 controls the charging voltage so that the difference ΔE between the energy E and the target energy Et is within an allowable range. After the difference ΔE is within the allowable range, the laser processor 190 sends a reception preparation completion signal indicating the completion of the reception preparation for the light emission trigger Tr to the exposure processor 230.

[0082] When the exposure processor 230 receives the reception preparation completion signal, it sends the light emission trigger Tr to the laser processor 190. When the laser processor 190 opens the shutter 170 in synchronization with the reception of the light emission trigger Tr, the laser light passing through the shutter 170 enters the exposure device 200. This laser light is, for example, pulsed laser light with a central wavelength of 193 nm.

[0083] 2.3 Problems

[0084] As described above, the metal seal 310a includes a straight portion 351a and a bent portion 352a. The bent portion 352a of the metal seal 310a has a tendency to be less likely to be flattened in the pressing direction of the cavity main body 131M and the electrical insulation plate 135 compared to the straight portion 351a. In the bent portion 352a, when the metal seal 310a is not sufficiently flattened, there is a concern that the distance between the electrical insulation plate 135 and the cavity main body 131M may be different from the design value. Therefore, there is a concern that the distance between the electrode 134b fixed to the electrical insulation plate 135 and the electrode 134a disposed on the electrode holding portion 137 may be different from the design value. In addition, as described above, the metal seal 310b includes a straight portion 351b and a bent portion 352b. The bent portion 352b of the metal seal 310b has a tendency to be less likely to be flattened in the pressing direction of the upper cavity 131a and the lower cavity 131b compared to the straight portion 351b. When the bent portion 352b of the metal seal 310b is not sufficiently flattened, the distance between the upper cavity 131a and the lower cavity 131b is different from the design value, and there is a concern that the relative position of the laser light emitted from the discharge chamber 131 with respect to the lower cavity 131b may be different from the design value. Therefore, when the bent portions 352a and 352b are not sufficiently flattened, it is possible to emit laser light different from the design value.

[0085] Therefore, in the following embodiments, a discharge chamber 131 capable of emitting laser light according to a design value is illustrated.

[0086] 3. Description of Embodiment 1

[0087] Next, the discharge chamber 131, which is a discharge chamber for a gas laser device according to Embodiment 1, will be described. In addition, the same reference numerals are assigned to structures having the same configuration as those described above, and redundant descriptions are omitted unless otherwise specified. In addition, in some of the drawings, for ease of viewing, a part of a component may be omitted or briefly described.

[0088] 3.1 Structure

[0089] Figure 8 FIG. is a longitudinal sectional view of a metal seal 310a used in the discharge chamber 131 of the present embodiment along the length direction. The difference between the metal seal 310a of the present embodiment and the metal seal 310a of the comparative example is that when the bent portion 352a is regarded as a straight line, the winding pitch of the wire forming the spiral spring 320 at the bent portion 352a is larger than the winding pitch of the wire at the straight portion 351a. Therefore, in the metal seal 310a of the present embodiment, the radial spring constant of the bent portion 352a when regarded as a straight line is smaller than the radial spring constant of the straight portion 351a. Since the metal seal 310a is pressed and flattened in a specific radial direction, in the metal seal 310a of the present embodiment, the spring constant in the pressing direction of the bent portion 352a when regarded as a straight line is smaller than the spring constant in the pressing direction of the straight portion 351a. The spring constant is a value obtained by dividing the force applied to an object by the amount of deformation of the object. Therefore, when the bent portion 352a is regarded as a straight line and a predetermined force is applied in the pressing direction, the amount of flattening of the bent portion 352a is larger than the amount of flattening of the straight portion 351a. In this example, in the straight portion 351a, the adjacent wires forming the spiral spring 320 are in contact with each other without a gap, and when the bent portion 352a is regarded as a straight line, a gap is formed between the adjacent wires of the bent portion 352a.

[0090] In addition, in the Figure 5 state, the spring constant in the pressing direction of the bent portion 352a of the metal seal 310a is preferably the same as the spring constant in the pressing direction of the straight portion 351a.

[0091] Next, a modified example of the structure in which the spring constant in the pressing direction of the bent portion 352a when regarded as a straight line is smaller than the spring constant in the pressing direction of the straight portion 351a will be described.

[0092] Figure 9is a longitudinal cross-sectional view of the first modified example of the metal seal 310a. As Figure 9 shown, in this modified example, the winding pitch of the wire forming the helical spring 320 at the bent portion 352a is larger than the winding pitch of the wire at the straight portion 351a, and a retainer 321 is disposed between the wires at the bent portion 352a. The retainer 321 is a plate-like member, and the size in the in-plane direction is smaller than the diameter of the helical spring 320. Therefore, a gap is formed between the retainer 321 and the outer skin 330 in the pressing direction in which the metal seal 310a is pressed. Accordingly, it is possible to prevent the retainer 321 from hindering the flattening of the metal seal 310a. As a material for the retainer 321, for example, resin can be cited. By disposing the retainer 321 between the wires, it is possible to prevent the winding pitch of the wires from becoming smaller at the bent portion 352a, and it is possible to prevent the spring constant in the pressing direction at the bent portion 352a from increasing.

[0093] Figure 10 is a longitudinal cross-sectional view of the second modified example of the metal seal 310a. As Figure 10 shown, in this modified example, the thickness of the wire forming the helical spring 320 at the bent portion 352a is smaller than the thickness of the wire at the straight portion 351a. Further, in this example, the winding pitch of the wire at the bent portion 352a is the same as the winding pitch of the wire at the straight portion 351a. However, the winding pitch of the wire at the bent portion 352a may be larger or smaller than the winding pitch of the wire at the straight portion 351a. In this example, it is possible to reduce the spring constant in the pressing direction of the bent portion 352a regardless of the winding pitch of the wire.

[0094] Figure 11 is a longitudinal cross-sectional view of the third modified example of the metal seal 310a. As Figure 11 shown, in this modified example, the thickness and the winding pitch of the wire forming the helical spring 320 at the bent portion 352a are the same as the thickness and the winding pitch of the wire at the straight portion 351a. However, in this modified example, the materials of the wires at the straight portion 351a and the bent portion 352a are different from each other, and the Young's modulus of the wire forming the helical spring 320 at the bent portion 352a is smaller than the Young's modulus of the wire at the straight portion 351a. As a material for the wire at the bent portion 352a, for example, stainless steel can be cited, and as a material for the wire at the straight portion 351a, for example, steel can be cited. At the boundary between the straight portion 351a and the bent portion 352a, the wires of different materials are connected to each other by welding, for example.

[0095] Further, as long as the spring constant in the pressing direction when the bent portion 352a is regarded as being linear is smaller than the spring constant in the pressing direction of the straight portion 351a, they may be appropriately combined and used Figures 8 to 11Structure of the described metal seal 310a.

[0096] In addition, the metal seal 310b used in the discharge chamber 131 of the present embodiment has substantially the same structure as the metal seal 310a. Therefore, in the metal seal 310b, the spring constant in the pressing direction when the bent portion 352b is regarded as linear is also smaller than the spring constant in the pressing direction of the straight portion 351b.

[0097] 3.2 Function and Effect

[0098] In the discharge chamber 131 of the present embodiment, in the metal seals 310a and 310b, the spring constant in the pressing direction when the bent portions 352a and 352b are regarded as linear is smaller than the spring constant in the pressing direction of the straight portions 351a and 351b. Therefore, compared with the case where the spring constant in the pressing direction when the bent portions 352a and 352b are regarded as linear is the same as the spring constant in the pressing direction of the straight portions 351a and 351b, the metal seals 310a and 310b are more likely to be flattened at the bent portions 352a and 352b. Therefore, at the bent portion 352a, the metal seal 310a is not sufficiently flattened, so that it is possible to suppress the distance between the electrical insulating plate 135 and the chamber body 131M from being different from the design value. Therefore, the distance between the electrode 134b and the electrode 134a is suppressed from being different from the design value. In addition, since the bent portion 352b of the metal seal 310b is not sufficiently flattened, the distance between the upper chamber 131a and the lower chamber 131b is suppressed from being different from the design value, and the relative position of the laser beam emitted from the discharge chamber 131 with respect to the lower chamber 131b is suppressed from being different from the design value. Therefore, according to the discharge chamber 131 of the present embodiment, the laser beam can be emitted according to the design value.

[0099] 4. Description of Embodiment 2

[0100] Next, the discharge chamber 131 of the discharge chamber for a gas laser device according to Embodiment 2 will be described. In addition, the same reference numerals are given to the structures that are the same as those described above, and redundant descriptions are omitted unless otherwise specified.

[0101] 4.1 Structure

[0102] Figure 12 It is a cross-sectional view along the length direction of the metal seal 310a used in the discharge chamber 131 of the present embodiment. As Figure 12As shown, the metal seal 310a of the present embodiment is different from the metal seal 310a of the first embodiment in that it is composed of a metal tube 340. In the present embodiment, the wall thickness of the metal tube 340 at the bent portion 352a is smaller than the wall thickness of the metal tube 340 at the straight portion 351a. Therefore, the diameter of the inner peripheral surface of the metal tube 340 at the bent portion 352a is larger than the diameter of the inner peripheral surface of the metal tube 340 at the straight portion 351a. Therefore, in the metal seal 310a of the present embodiment, the radial spring constant of the bent portion 352a when regarded as linear is smaller than the radial spring constant of the straight portion 351a. Therefore, in the metal seal 310a of the present embodiment, the spring constant in the pressing direction of the bent portion 352a when regarded as linear is smaller than the spring constant in the pressing direction of the straight portion 351a. As described above, the spring constant refers to the value obtained by dividing the force applied to an object by the deformation amount of the object. Therefore, in the present embodiment, when the bent portion 352a is regarded as linear, when a prescribed force is applied in the pressing direction, the flattening amount of the bent portion 352a is larger than the flattening amount of the straight portion 351a.

[0103] In addition, in the present embodiment, as in the third modification of the first embodiment, the materials constituting the metal tube 340 in the straight portion 351a and the bent portion 352a may be different from each other, and the Young's modulus of the material constituting the metal tube 340 at the bent portion 352a is smaller than the Young's modulus of the material constituting the metal tube 340 at the straight portion 351a. In this case, for example, stainless steel can be cited as the material of the metal tube 340 at the bent portion 352a, and steel can be cited as the material of the metal tube 340 at the straight portion 351a. At the boundary between the straight portion 351a and the bent portion 352a, the metal tubes of different materials are connected to each other by welding, for example.

[0104] In addition, in the present embodiment, it is also preferable that Figure 5 in the state where, the spring constant in the pressing direction of the bent portion 352a of the metal seal 310a is the same as the spring constant in the pressing direction of the straight portion 351a. In addition, in the present embodiment, the metal seal 310b also has substantially the same structure as the metal seal 310a. In the metal seal 310b of the present embodiment, the spring constant in the pressing direction of the bent portion 352b when regarded as linear is also smaller than the spring constant in the pressing direction of the straight portion 351b.

[0105] 4.2 Function and Effect

[0106] In the discharge chamber 131 of the present embodiment, laser can also be emitted according to the design value in the same manner as in the first embodiment.

[0107] In addition, although different from the present embodiment, it is also possible that the wall thickness of the metal tube 340 is constant at the straight portion 351a and the bent portion 352a, and the Young's modulus of the material constituting the metal tube 340 at the bent portion 352a is smaller than the Young's modulus of the material constituting the metal tube 340 at the straight portion 351a.

[0108] As described above, the present invention has been described by taking the embodiment as an example, but the present invention can be appropriately modified. For example, as long as the spring constant of the metal seals 310a and 310b in the pressing direction when the bent portion 352a is regarded as linear is smaller than the spring constant in the pressing direction of the straight portion 351a, the structure may be different from the above-described embodiment. In addition, in the above-described embodiment, the metal seals 310a and 310b have a substantially rectangular shape. However, as long as the shapes of the metal seals 310a and 310b include the straight portions 351a and 351b and the bent portions 352a and 352b, they may not be rectangular. A modification example in which the shapes of the metal seals 310a and 310b are other than rectangular will be described. Figure 13 This is a diagram showing another modification example of the metal seal 310a. As Figure 13 shown, the metal seal 310a has a track shape including a straight portion 351a and a bent portion 352a. In addition, although not particularly shown, the shape of the metal seal 310b may also be a track shape.

[0109] In addition, the metal seals 310a and 310b may not have substantially the same structure. Specifically, for example, the metal seal 310a may be configured as in the above-described embodiment, and the metal seal 310b may be configured differently from the above-described embodiment.

[0110] In addition, as examples of the first chamber member and the second chamber member, the upper chamber 131a and the lower chamber 131b and the chamber body 131M and the electrical insulation plate 135 are given as examples. However, the first chamber member and the second chamber member may be other members as long as they are members that surround at least a part of the internal space of the discharge chamber 131 by being combined with each other.

[0111] The above description is illustrative rather than restrictive. Therefore, it will be apparent to those skilled in the art that modifications can be made to the embodiments of the present disclosure without departing from the scope of the claims. Additionally, it will also be apparent to those skilled in the art to use the embodiments of the present disclosure in combination. Unless otherwise specified, the terms used in this specification and the claims should be construed as "non-restrictive" terms. For example, terms such as "comprising," "having," "including," and "containing" should be construed as "not excluding the existence of elements other than those recited." In addition, the modifier "a" should be construed to mean "at least one" or "one or more." Further, the term "at least one of A, B, and C" should be construed as "A," "B," "C," "A + B," "A + C," "B + C," or "A + B + C," and should also be construed to include combinations with parts other than A, B, and C.

Claims

1. A discharge chamber for a gas laser device, which has a pair of discharge electrodes disposed opposite to each other with a space therebetween in an internal space and in which a laser gas is sealed. Among them, The discharge chamber for the gas laser device includes: A first chamber member and a second chamber member, which surround at least a part of the internal space by being combined with each other; and A metal seal, which includes a straight portion and a bent portion, and is disposed between the first chamber member and the second chamber member, and is pressed by the first chamber member and the second chamber member to seal a gap between the first chamber member and the second chamber member. The spring constant of the bent portion of the metal seal in the pressing direction when regarded as being linear is smaller than the spring constant of the straight portion in the pressing direction.

2. The discharge chamber for the gas laser device according to claim 1, wherein The metal seal includes a metal outer skin and a helical spring surrounded by the outer skin.

3. The discharge chamber for the gas laser device according to claim 2, wherein The winding pitch of the wire forming the helical spring at the bent portion is larger than the winding pitch at the straight portion.

4. The discharge chamber for the gas laser device according to claim 3, wherein A retainer is disposed between the wires at the bent portion.

5. The discharge chamber for the gas laser device according to claim 4, wherein The retainer is made of resin.

6. The discharge chamber for the gas laser device according to claim 2, wherein The thickness of the wire forming the helical spring at the bent portion is smaller than the thickness of the wire at the straight portion.

7. The discharge chamber for the gas laser device according to claim 2, wherein The Young's modulus of the wire forming the helical spring at the bent portion is smaller than the Young's modulus of the wire at the straight portion.

8. The discharge chamber for the gas laser device according to claim 7, wherein The wire at the bent portion is stainless steel, The wire at the straight portion is steel.

9. The discharge chamber for the gas laser device according to claim 1, wherein The metal seal is composed of a metal tube, The wall thickness of the metal tube at the bent portion is smaller than the wall thickness at the straight portion.

10. The discharge chamber for the gas laser device according to claim 1, wherein The spring constant of the bent portion of the metal seal in the pressing direction is the same as the spring constant of the straight portion in the pressing direction.

11. The discharge chamber for the gas laser device according to claim 1, wherein The first chamber member is an upper chamber constituting at least a part of the upper side of the discharge chamber for the gas laser device, and the second chamber member is a lower chamber constituting at least a part of the lower side of the discharge chamber for the gas laser device.

12. The discharge chamber for the gas laser device according to claim 1, wherein The first chamber member is a chamber body that constitutes the main body of the discharge chamber for the gas laser device and has an opening at the upper part, and the second chamber member is a cover that closes the opening.

13. The discharge chamber for the gas laser device according to claim 12, wherein The cover body is an insulating plate on which the discharge electrode is fixed.

14. A method for manufacturing an electronic device, comprising the following steps: Generating laser light by a gas laser device including a discharge chamber for the gas laser device, Outputting the laser light to an exposure device, Exposing the laser light on a photosensitive substrate in the exposure device to manufacture an electronic device, The discharge chamber for the gas laser device has a pair of discharge electrodes disposed opposite each other with a space therebetween in the internal space, and a laser gas is sealed therein, The discharge chamber for the gas laser device includes: A first chamber member and a second chamber member that surround at least a part of the internal space by being combined with each other; and A metal seal including a straight portion and a bent portion, disposed between the first chamber member and the second chamber member, and pressed by the first chamber member and the second chamber member to seal a gap between the first chamber member and the second chamber member, The spring constant in the pressing direction of the bent portion of the metal seal is smaller than the spring constant in the pressing direction of the straight portion when the bent portion is regarded as linear.

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