Cavity of gas laser device, gas laser device, and method for manufacturing electronic device

Abstract

A cavity of a gas laser device in which a laser gas is sealed in an internal space, the cavity comprising: a first main electrode and a second main electrode, the longitudinal directions of which are along a predetermined direction and which face each other in the internal space so as to be separated from each other; a window which is provided on a wall surface of the cavity and through which light from the internal space passes; and a first pre-ionization electrode provided on one side of the first main electrode, the first pre-ionization electrode having a first dielectric tube extending in the longitudinal direction, a first pre-ionization inner electrode disposed inside the first dielectric tube and extending in the longitudinal direction, and a first pre-ionization outer electrode extending in the longitudinal direction. And a first preionization external electrode including a first end portion facing the outer peripheral surface of the first dielectric tube, the first preionization external electrode extending from the first end portion in a direction away from the first dielectric tube, and a first corona discharge angle being an acute angle in a plane perpendicular to the longitudinal direction.

Description

Technical Field

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

[0002] In recent years, in semiconductor exposure devices, as semiconductor integrated circuits become smaller and more highly integrated, there is a demand for improved resolution. Therefore, the wavelength of light emitted from an exposure light source has been shortened. For example, as a gas laser device for exposure, a KrF excimer laser device that outputs a laser with a wavelength of about 248nm and an ArF excimer laser device that outputs a laser with a wavelength of about 193nm are used.

[0003] The spectral line width of the natural oscillation light of the KrF excimer laser device and the ArF excimer laser device is relatively wide, at 350pm to 400pm. Therefore, when a projection lens is constructed using a material that allows ultraviolet light such as KrF and ArF lasers to pass through, chromatic aberration sometimes occurs. 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 is invisible. 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 whose spectral line width is narrowed is referred to as a narrowed gas laser device.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-177169

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 5-327070 Summary of the invention

[0008] A cavity of a gas laser device according to one embodiment of the present disclosure comprises: a first main electrode and a second main electrode, the length direction of which is along a predetermined direction, and which are spaced apart from each other and face each other in an internal space; a window provided on a wall surface of the cavity, and through which light from the internal space passes; and a first preionization electrode provided on one side of the first main electrode, the first preionization electrode comprising a first dielectric tube extending in the length direction, a first preionization inner electrode arranged inside the first dielectric tube and extending in the length direction, and a first preionization inner electrode extending in the length direction. An outer electrode, the first preionization outer electrode includes a first end portion opposite to the outer peripheral surface of the first dielectric tube, and extends from the first end portion in a direction away from the first dielectric tube. In a plane perpendicular to the longitudinal direction, a first corona discharge angle toward the space between the first main electrode and the second main electrode among the angles formed by a first tangent line and the following straight line is an acute angle, the first tangent line is tangent to the first dielectric tube at a first prescribed position closest to the first end portion in the first dielectric tube, and the straight line passes through the first prescribed position and extends in the direction in which the first preionization outer electrode extends from the first end portion.

[0009] A gas laser device according to one embodiment of the present disclosure has a cavity in which laser gas is sealed in an internal space, wherein the cavity has: a first main electrode and a second main electrode, whose length directions are along a predetermined direction, and which are spaced apart from each other and opposed in the internal space; a window provided on a wall surface of the cavity, through which light from the internal space passes; and a first pre-ionization electrode provided on one side of the first main electrode, the first pre-ionization electrode having a first dielectric tube extending in the length direction, a first pre-ionization inner electrode arranged inside the first dielectric tube and extending in the length direction, and a second pre-ionization inner electrode extending in the length direction. A first preionization outer electrode extending in a direction, the first preionization outer electrode includes a first end portion opposite to the outer peripheral surface of the first dielectric tube, and extends from the first end portion in a direction away from the first dielectric tube. In a plane perpendicular to the longitudinal direction, a first corona discharge angle toward the space between the first main electrode and the second main electrode among the angles formed by a first tangent and the following straight line is an acute angle, the first tangent is tangent to the first dielectric tube at a first prescribed position closest to the first end portion in the first dielectric tube, and the straight line passes through the first prescribed position and extends in the direction in which the first preionization outer electrode extends from the first end portion.

[0010] A method for manufacturing an electronic device according to one embodiment of the present disclosure includes the following steps: generating laser light by a gas laser device, outputting the laser light to an exposure device, and exposing the laser light on a photosensitive substrate in the exposure device to manufacture the electronic device, wherein a cavity of the gas laser device seals a laser gas in an internal space, and the cavity comprises: a first main electrode and a second main electrode, whose length directions are along a predetermined direction and which are spaced apart from each other and opposed in the internal space; a window, which is provided on a wall surface of the cavity, and through which light from the internal space passes; and a first pre-ionization electrode, which is provided on one side of the first main electrode, and comprises a first dielectric tube extending in a length direction and a second dielectric tube disposed on the first dielectric tube. A first preionization inner electrode is provided inside the dielectric tube and extends along the length direction, and a first preionization outer electrode is provided along the length direction, the first preionization outer electrode includes a first end portion opposite to the outer peripheral surface of the first dielectric tube, and extends from the first end portion toward a direction away from the first dielectric tube. In a plane perpendicular to the length direction, a first corona discharge angle toward a space between the first main electrode and the second main electrode among the angles formed by a first tangent and the following straight line is an acute angle, the first tangent is tangent to the first dielectric tube at a first prescribed position closest to the first end portion in the first dielectric tube, and the straight line passes through the first prescribed position and extends in a direction in which the first preionization outer electrode extends from the first end portion. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0014] Figure 3 This is a cross-sectional view of the cavity of the comparative example, taken perpendicularly to the direction in which the laser beam travels.

[0015] Figure 4 is a circuit diagram in a cavity of a comparative example.

[0016] Figure 5 This is a diagram of the periphery of the preionization electrode in Embodiment 1 as viewed along the Z direction.

[0017] Figure 6 yes Figure 5 An enlarged view of the first end and its surrounding area is shown.

[0018] Figure 7 It is a diagram showing the simulation result of the relationship between the first corona discharge angle and the light emitting area of ​​ultraviolet light.

[0019] Figure 8 This is a diagram showing simulation results of the relationship between the angle α and the first corona discharge angle according to the first embodiment.

[0020] Fig. 9 It is shown Figure 8 A diagram showing the relationship between the angle α and the first corona discharge angle within a preferred range and the relationship between the angle α and the pre-ionization intensity.

[0021] Fig.10 It is shown Figure 8 FIG. 5 is a graph showing the relationship between the angle α and the first corona discharge angle when the first corona discharge angle is 90°, and the relationship between the angle α and the pre-ionization intensity.

[0022] Fig.11 This is a diagram of the periphery of the preionization electrode in the modification of the first embodiment as viewed along the Z direction.

[0023] Fig.12 This is a circuit diagram in a cavity according to a modified example of the first embodiment.

[0024] Fig.13 This is a diagram of the periphery of the preionization electrode in Embodiment 2 as viewed along the Z direction.

[0025] Fig.14 yes Fig.13 An enlarged view of the first end and its surrounding area is shown.

[0026] Fig.15 This is a diagram showing simulation results of the relationship between the angle α and the first corona discharge angle according to the second embodiment.

[0027] Fig.16 It is shown Fig.15 A diagram showing the relationship between the angle α and the first corona discharge angle within a preferred range and the relationship between the angle α and the pre-ionization intensity.

[0028] Fig.17 It is shown Fig.15 FIG. 5 is a graph showing the relationship between the angle α and the first corona discharge angle when the first corona discharge angle is 90°, and the relationship between the angle α and the pre-ionization intensity.

[0029] Fig.18 This is a diagram of the periphery of the preionization electrode in Embodiment 3 as viewed along the Z direction.

[0030] Fig.19 This is a circuit diagram in the cavity of Embodiment 3.

[0031] Fig. 20 This is a diagram of the periphery of the preionization electrode in Embodiment 4 as viewed along the Z direction.

[0032] Fig.21 This is a circuit diagram in the cavity of embodiment 4. DETAILED DESCRIPTION

[0033] 1. Description of the electronic device manufacturing apparatus used in the exposure process of the electronic device

[0034] 2. Description of the gas laser device of the comparative example

[0035] 2.1 Structure

[0036] 2.2 Actions

[0037] 2.3 Topics

[0038] 3. Description of the cavity of embodiment 1

[0039] 3.1 Structure

[0040] 3.2 Effects

[0041] 4. Description of the cavity of Embodiment 2

[0042] 4.1 Structure

[0043] 4.2 Effects

[0044] 5. Description of the cavity of Embodiment 3

[0045] 5.1 Structure

[0046] 5.2 Effects

[0047] 6. Description of the Cavity of Embodiment 4

[0048] 6.1 Structure

[0049] 6.2 Action / Effect

[0050] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0051] The embodiments described below illustrate several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and actions described in each embodiment are not necessarily all necessary for the structures and actions of the present disclosure. In addition, the same reference numerals are marked on the same structural elements and repeated descriptions are omitted. In the accompanying drawings referred to below, the sizes of each component are sometimes changed for easy understanding.

[0052] 1. Description of the electronic device manufacturing apparatus used in the exposure process of the electronic device

[0053] Figure 1 Schematic diagram showing an overall schematic configuration example of an electronic device manufacturing apparatus used in an exposure process of an electronic device. Figure 1As shown, the manufacturing device 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, and the illumination optical system 210 includes a plurality of reflectors 211, 212, and 213. The illumination optical system 210 illuminates the mask pattern of the mask stage RT by the laser light incident from the gas laser device 100. The projection optical system 220 performs reduced projection of the laser light transmitted through the mask so as to image it on a 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 causes the mask stage RT and the workpiece stage WT to move in parallel synchronously, thereby causing the laser light reflecting the mask pattern to expose the workpiece. By transferring the device pattern on the semiconductor wafer through the above exposure process, a semiconductor device as an electronic device can be manufactured.

[0054] 2. Description of the gas laser device of the comparative example

[0055] 2.1 Structure

[0056] A gas laser device 100 of a comparative example will be described. The comparative examples of the present disclosure are examples that the applicant recognizes as being known only to the applicant, and are not examples that the applicant acknowledges as being publicly known.

[0057] Figure 2 1 is a schematic diagram showing an overall schematic structural example 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 a laser having a central wavelength of approximately 193 nm. In addition, 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 outputs a laser 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.

[0058] The gas laser device 100 includes a housing 110 , a laser oscillator 130 disposed in an internal space of the housing 110 , a monitor module 160 , a shutter 170 , and a laser processor 190 as main components.

[0059] The laser oscillator 130 includes a cavity device CH, 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 cavity device CH viewed from a direction substantially perpendicular to the traveling direction of the laser light is shown.

[0060] As a material of the cavity 131 of the cavity device CH, for example, a metal such as nickel-plated aluminum or nickel-plated stainless steel can be cited. The cavity 131 includes an internal space where light is generated by the excitation of the laser medium in the above-mentioned laser gas. The light travels toward the windows 139a and 139b described later. The laser gas is supplied to the internal space of the cavity 131 from a laser gas supply source not shown in the figure through a pipe not shown in the figure. In addition, the laser gas in the cavity 131 is subjected to a treatment such as removing F2 gas through a halogen filter, and is discharged to the outside of the housing 110 through a pipe not shown in the figure by an exhaust pump not shown in the figure.

[0061] In the internal space of the cavity 131, the electrode 133a as the first main electrode and the electrode 133b as the second main electrode are separated and opposed to each other, and the length direction of each is along the traveling direction of the laser. In the following, the length direction of the electrodes 133a and 133b is sometimes set as the Z direction, the arrangement direction of the electrodes 133a and 133b and the separation direction in which the electrodes 133a and 133b are separated from each other and the direction perpendicular to the Z direction is set as the Y direction, and the direction perpendicular to the Y direction and the Z direction is set as the X direction for explanation. The electrodes 133a and 133b are discharge electrodes for exciting the laser medium by glow discharge. In this example, the electrode 133a is the cathode and the electrode 133b is the anode.

[0062] The electrode 133a is supported by and electrically connected to the electrode holder portion 137. The electrode 133b is fixed to the surface of the plate-shaped electrical insulating portion 135 on the side of the internal space of the cavity 131 by a conductive member 157 composed of bolts, for example. The conductive member 157 is electrically connected to the pulse power module 143, and the high voltage from the pulse power module 143 is applied to the electrode 133b.

[0063] The electrical insulating portion 135 includes an insulator. As for the material of the electrical insulating portion 135, for example, an alumina ceramic having low reactivity with F2 gas can be cited. In addition, the electrical insulating portion 135 only needs to have electrical insulation, and as the material of such electrical insulating portion 135, resins such as phenolic resin and fluororesin, or quartz, glass, etc. are cited. The electrical insulating portion 135 blocks the opening provided in the cavity 131 and is fixed to the cavity 131.

[0064] The charger 141 is a DC power supply device that charges a charging capacitor (not shown) in the pulse power module 143 with a predetermined voltage. The pulse power module 143 includes a switch 143a controlled by the laser processor 190. When the switch 143a is turned from off to on, the pulse power module 143 generates a pulse-shaped high voltage using the electric energy charged in the charging capacitor, and applies the high voltage between the electrode 133a and the electrode 133b.

[0065] When a high voltage is applied between the electrode 133a and the electrode 133b, a discharge occurs between the electrode 133a and the electrode 133b. The laser medium in the cavity 131 is excited by the energy of the discharge, and the excited laser medium emits light when it transitions to a ground state.

[0066] A pair of windows 139a and 139b are provided on the wall surface of the cavity 131. The window 139a is located at one end side of the traveling direction of the laser in the cavity 131, and the window 139b is located at the other end side of the traveling direction. The windows 139a and 139b sandwich the space between the electrode 133a and the electrode 133b. The windows 139a and 139b are inclined at a Brewster angle with respect to the traveling direction of the laser to suppress the reflection of the P polarized light of the laser. The laser light oscillating as described later is emitted to the outside of the cavity 131 through the windows 139a and 139b.

[0067] The narrowband module 145 includes a housing 145a, a prism 145b, a grating 145c and a rotating table (not shown) arranged in the inner space of the housing 145a. The housing 145a has an opening, and the housing 145a is connected to the rear side of the cavity 131 through the opening.

[0068] The prism 145b expands the beam width of the light emitted from the window 139a and causes 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 cavity 131 via the window 139a. The prism 145b is supported by a rotating table and rotated by the rotating table. The rotation of the prism 145b changes the incident angle of the light relative 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 cavity 131. Figure 2 , an example in which one prism 145b is arranged is shown; however, at least one prism may be arranged.

[0069] The surface of the grating 145c is made of a material with high reflectivity, and a plurality of grooves are provided on the surface at predetermined intervals. 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 is diffracted in a direction corresponding to the wavelength of the light. The grating 145c is configured in a Littrow manner so 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 is returned to the cavity 131 via the prism 145b.

[0070] The output coupling mirror 147 is arranged in the inner space of the optical path tube 147a connected to the front side of the cavity 131, and faces the window 139b. The output coupling mirror 147 allows a part of the laser light emitted from the window 139b to pass toward the monitor module 160, and reflects the other part and returns to the inner space of the cavity 131 through the window 139b. In this way, a Fabry-Perot type laser resonator is formed by the grating 145c and the output coupling mirror 147, and the cavity 131 is arranged on the optical path of the laser resonator.

[0071] The monitor module 160 is arranged on the optical path of the laser light emitted from the output coupling mirror 147. The monitor module 160 includes a housing 161, a beam splitter 163 and a light sensor 165 arranged in the internal space of the housing 161. 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.

[0072] The beam splitter 163 transmits a portion of the laser light emitted from the output coupling mirror 147 toward the shutter 170 and reflects the other portion of the laser light toward the light receiving surface of the optical sensor 165. The 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 the laser processor 190.

[0073] 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 gas laser device 100 as a whole.

[0074] The laser processor 190 sends and receives various signals to and from the exposure processor 230 of the exposure device 200. For example, the laser processor 190 receives signals indicating the light emission trigger Tr and target energy Et described later from the exposure processor 230. The target energy Et is a target value of the energy of the laser used in the exposure process. The laser processor 190 controls the charging voltage of the charger 141 according to the energy E and the target energy Et received from the light sensor 165 and the exposure processor 230. By controlling the charging voltage, the energy of the laser is controlled. In addition, the laser processor 190 sends a command signal for turning on or off the switch 143a to the pulse power module 143. In addition, the laser processor 190 is electrically connected to the shutter 170 to control the opening and closing of the shutter 170.

[0075] 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 the allowable range. After the difference ΔE is within the allowable range, the laser processor 190 sends a reception preparation completion signal notifying that the reception preparation of the light emission trigger Tr is completed to the exposure processor 230. Upon receiving the reception preparation completion signal, the exposure processor 230 sends a signal indicating the light emission trigger Tr to the laser processor 190, and upon receiving the signal indicating the light emission trigger Tr, the laser processor 190 opens the shutter 170. The light emission trigger Tr is defined by a predetermined repetition frequency f of the laser and a predetermined number of pulses P, and 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 repetition frequency f of the laser is, for example, not less than 100 Hz and not more than 10 kHz.

[0076] The optical shutter 170 is arranged on the optical path of the laser in the internal space of the optical path tube 171, and the optical path tube 171 is connected to an opening formed in the housing 161 of the monitor module 160 on the side opposite to the side connected to the optical path tube 147a. The internal space of the optical path tubes 171 and 147a and the internal space of the housings 161 and 145a are supplied and filled with a purge gas. The purge gas contains an inactive 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 path tube 171 is connected to the exposure device 200 through the opening of the housing 110 and the optical path tube 500, and the optical path tube 500 connects the housing 110 and the exposure device 200. The laser light after passing through the optical shutter 170 is incident on the exposure device 200.

[0077] 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 execute various processes included in the present disclosure. In addition, the exposure processor 230 controls the exposure device 200 as a whole.

[0078] Figure 3 1 is a cross-sectional view perpendicular to the traveling direction of the laser beam of the cavity 131 of the comparative example. A cross-flow fan 149 and a heat exchanger 151 are further arranged in the internal space of the cavity 131 .

[0079] The cross flow fan 149 and the heat exchanger 151 are arranged on the side opposite to the electrode 133a with reference to the electrode holder 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 space between the electrode 133a and the electrode 133b. 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 a liquid or gas cooling medium. Figure 2 As 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. The cross flow fan 149 rotates, thereby the laser gas sealed in the internal space of the chamber 131 is rotated as shown in FIG. Figure 3 The laser gas circulates as shown by the thick arrow in the middle. That is, the laser gas circulates in the order of the cross-flow fan 149, between the electrode 133a and the electrode 133b, the heat exchanger 151, and the cross-flow fan 149. At least a part of the circulating laser gas passes through the heat exchanger 151, and the temperature of the laser gas is adjusted by the heat exchanger 151. Through the circulation of the laser gas, impurities in the laser gas generated by the main discharge between the electrode 133a and the electrode 133b move to the downstream side, and in the next discharge, fresh laser gas is supplied between the electrode 133a and the electrode 133b. In addition, when the laser gas passes through the heat exchanger 151, the heat associated with the main discharge is removed, and the temperature rise of the laser gas is suppressed. The on / off and rotation speed of the motor 149a are controlled by the laser processor 190. Therefore, the laser processor 190 can adjust the circulation speed of the laser gas circulating in the internal space of the cavity 131 by controlling the motor 149a.

[0080] The electrode holder 137 is electrically connected to the cavity 131 via the wiring 137a. The electrode 133a supported by the electrode holder 137 is connected to the ground potential via the electrode holder 137, the wiring 137a, and the cavity 131.

[0081] The electrode holder 137 is provided with a preionization electrode 10 on the side of the electrode 133a. The preionization electrode 10 is arranged on the upstream side of the laser gas flowing along the X direction between the electrode 133a and the electrode 133b. 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 are sometimes referred to as the inner electrode 13 and the outer electrode 15, respectively.

[0082] The dielectric tube 11 is, for example, cylindrical, and is disposed with its longitudinal direction along the Z direction. Examples of the material of the dielectric tube 11 include alumina ceramics and sapphire.

[0083] The internal electrode 13 is in a rod shape, is disposed inside the dielectric tube 11, and extends in the Z direction. Examples of the material of the internal electrode 13 include copper and brass.

[0084] The external electrode 15 is provided between the dielectric tube 11 and the electrode 133a, and extends in the Z direction. The external electrode 15 includes an end 15a that faces a portion of the outer peripheral surface of the dielectric tube 11. The end 15a is provided in the range from one end to the other end of the external electrode 15 in the Z direction. The external electrode 15 extends from the end 15a in a direction away from the dielectric tube 11. In addition, the external electrode 15 is bent on the plane perpendicular to the Z direction, that is, the XY plane, and the end 15a contacts the outer peripheral surface of the dielectric tube 11 in a manner of pressing the outer peripheral surface of the dielectric tube 11 by bending. The end 15a contacts the outer peripheral surface of the dielectric tube 11 over the entire length in the Z direction. A threaded hole (not shown) is provided at the end of the external electrode 15 on the side opposite to the end 15a, and the external electrode 15 is fixed to the guide 17 by a screw (not shown) screwed into the threaded hole. The guide 17 is fixed to the electrode 133a. Therefore, it can be understood that the external electrode 15 is fixed to the electrode 133a via the guide 17. In addition, the external electrode 15 may be fixed between the dielectric tube 11 and the electrode 133a, or may be directly fixed to the electrode 133a. Examples of the material of the external electrode 15 include copper and brass. The external electrode 15 may also be manufactured by bending a plate-like member.

[0085] The electrode holder 137 is provided with a guide 18 on the side of the electrode 133a on the opposite side from the guide 17. Therefore, the electrode 133a is sandwiched between the guides 17 and 18. The guides 17 and 18 guide the laser gas so that the laser gas from the cross flow fan 149 flows between the electrode 133a and the electrode 133b. As a material of the guides 17 and 18, for example, porous nickel metal with low reactivity with F2 gas can be cited.

[0086] A pair of holders (not shown) are fixed to the electrode holder part 137 on the side of the electrode 133a. One end of the dielectric tube 11 is inserted into a hole (not shown) of one holder, and the other end of the dielectric tube 11 is inserted into a hole (not shown) of the other holder. Thus, the dielectric tube 11 is held by the holder.

[0087] Figure 41 is a circuit diagram in the cavity 131 of the comparative example. A peaking capacitor 31a and a pre-ionization capacitor 31b are also arranged in the cavity 131. The inner electrode 13 is electrically connected to one end of the pre-ionization capacitor 31b via the current introduction terminal 31c. The outer electrode 15 is electrically connected to the electrode 133a via the electrode holder 137, and is electrically connected to the cavity 131 via the electrode holder 137 and the wiring 137a. The outer electrode 15, the electrode holder 137, the wiring 137a and the cavity 131 are at the ground potential. When the switch 143a of the pulse power module 143 is turned on, the pulse power module 143 is electrically connected to the peaking capacitor 31a and the pre-ionization capacitor 31b, so that the charge accumulated in the charging capacitor of the pulse power module 143 (not shown) is transferred to the peaking capacitor 31a and the pre-ionization capacitor 31b. In addition, a voltage is applied between the outer electrode 15 and the inner electrode 13 so that the potential of the outer electrode 15 is higher than the potential of the inner electrode 13.

[0088] 2.2 Action

[0089] Next, the operation of the gas laser device 100 according to the comparative example will be described.

[0090] Before the gas laser device 100 emits laser light, purge gas is filled from a purge gas supply source (not shown) into the inner space of the optical path tubes 147a, 171, 500 and the inner space of the housings 145a, 161. In addition, laser gas is supplied from a laser gas supply source (not shown) into the inner space of the cavity 131. When the laser gas is supplied, the laser processor 190 controls the motor 149a to rotate the cross flow fan 149. The rotation of the cross flow fan 149 causes the laser gas to circulate in the inner space of the cavity 131.

[0091] 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 light emission trigger Tr from the exposure processor 230. In addition, the laser processor 190 turns on the switch 143a of the pulse power module 143. As a result, the pulse power module 143 applies a pulse-shaped high voltage between the electrode 133a and the electrode 133b and between the inner electrode 13 and the outer electrode 15 using the electric energy charged by the charging capacitor (not shown). When the high voltage is applied between the inner electrode 13 and the outer electrode 15, corona discharge is generated near the dielectric tube 11 and the end 15a, and ultraviolet light is radiated. When the ultraviolet light irradiates the laser gas between the electrode 133a and the electrode 133b, the laser gas between the electrode 133a and the electrode 133b is pre-ionized. After the pre-ionization, when the voltage between the electrode 133a and the electrode 133b reaches the insulation breakdown voltage, the main discharge between the electrode 133a and the electrode 133b is generated. Thus, excimers are generated from the laser medium contained in the laser gas between the electrode 133a and the electrode 133b, and light is emitted when dissociated. Through this light, the light resonates between the grating 145c and the output coupling mirror 147, and the light is amplified every time it passes through the discharge space in the internal space of the cavity 131, generating laser oscillation. Then, a part of the laser light passes through the output coupling mirror 147 as a pulsed laser and travels toward the beam splitter 163.

[0092] Part of the laser light traveling toward the beam splitter 163 is reflected by the beam splitter 163 and received by the optical sensor 165. The optical sensor 165 measures the energy E of the received laser light and outputs a signal indicating 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 the allowable range.

[0093] 2.3 Topics

[0094] In the gas laser device 100 of the comparative example, when the preionization intensity of the preionization electrode 10 between the electrode 133a and the electrode 133b is low, an unstable main discharge is generated. As a result, the stability of the energy of the laser light emitted from the gas laser device 100 may be reduced. As a result, the laser light satisfying the required performance may not be emitted from the exposure device 200. Therefore, there is a demand for increasing the preionization intensity.

[0095] Therefore, in the following embodiments, the cavity 131 of the gas laser device 100 that can increase the pre-ionization intensity is exemplified.

[0096] 3. Description of the cavity of embodiment 1

[0097] Next, the cavity 131 of this embodiment is described. In addition, the same reference numerals are used for the same structures as those described above, and repeated descriptions are omitted except for special descriptions. In addition, in some drawings, a part of the components is sometimes omitted or briefly described for easy viewing.

[0098] 3.1 Structure

[0099] Figure 5 2 is a diagram showing the periphery of the preionization electrode in the present embodiment as viewed along the Z direction. Figure 5 In FIG. 1 , the flow of the laser gas is shown by bold arrows.

[0100] For convenience of description, the following description assumes that the preionization electrode is a first preionization electrode. In addition, the first preionization electrode may be referred to as a preionization electrode 60. The preionization electrode 60 is the same as the preionization electrode 10 of the comparative example.

[0101] For the sake of convenience, the components of the preionization electrode 60 are respectively the first dielectric tube, the first preionization inner electrode, the first preionization outer electrode, and the first end of the first preionization outer electrode, and are sometimes referred to as the dielectric tube 61, the inner electrode 63, the outer electrode 65, and the first end 65a. In addition, regarding the guide 17, the reference numeral is sometimes changed to 67 and referred to as the first guide 67.

[0102] In the preionization electrode 60 of the present embodiment, the first corona discharge angle θ1 at the first end portion 65 a is an acute angle, which is different from the comparative example in which the first corona discharge angle θ1 is an obtuse angle.

[0103] The first corona discharge angle θ1 is an angle toward the space S between the electrode 133a and the electrode 133b, among the angles formed by the first tangent line 41a and the straight line 41b in a plane perpendicular to the Z direction, that is, the Z direction. That is, the first corona discharge angle θ1 is an angle on the side where the laser gas between the electrode 133a and the electrode 133b is pre-ionized. The first tangent line 41a is a straight line that is tangent to the dielectric tube 61 at the first predetermined position P1 closest to the first end 65a in the dielectric tube 61. The straight line 41b is a line that passes through the first predetermined position P1 and extends in the direction in which the outer electrode 65 extends from the first end 65a. In the present embodiment, the first end 65a contacts a portion of the outer peripheral surface of the dielectric tube 61, and therefore, the first predetermined position P1 is also a contact position where the first end 65a contacts the portion.

[0104] Figure 6 yes Figure 5 An enlarged view of the first end portion 65a and its surroundings is shown. Figure 6 In the figure, the guide member 18 is omitted. Figure 6In the equation (L1), the radius of the dielectric tube 61 is represented by r, and a straight line that is orthogonal to the separation direction of the electrodes 133a and 133b and passes through the center C of the dielectric tube 61 in a plane perpendicular to the Z direction is represented by a first straight line L1. In addition, the distance in the separation direction from the first straight line L1 to the first facing surface 134a of the electrode 133a facing the electrode 133b is represented by y1. In addition, the distance in the X direction from the center C of the dielectric tube 61 to the side surface of the electrode 133a facing the dielectric tube 61 is represented by x1. The dielectric tube 61 of the present embodiment is arranged so that the following equations (1) and (2) are satisfied.

[0105] y1≥r···(1)

[0106] x1>r···(2)

[0107] exist Figure 6 In the embodiment, the angle formed between the second straight line L2 and the first straight line L1 in the plane perpendicular to the Z direction is represented by α, and the second straight line L2 passes through the first predetermined position P1 closest to the first end 65a in the dielectric tube 61 and the center C of the dielectric tube 61. In addition, in the present embodiment, the angle formed between the third straight line L3 and the first straight line L1 in the plane perpendicular to the Z direction is represented by β1, and the third straight line L3 passes through the center C of the dielectric tube 61 and the edge of the first facing surface 134a on the dielectric tube 61 side. Angles α and β1 are acute angles. In the cavity 131 of the present embodiment, the following equations (3) and (4) are established.

[0108] 0≤α<β1···(3)

[0109] (90°+α-tan -1 ((y1-rsinα) / (x1-rcosα)))≤θ1<90°···(4)

[0110] Figure 7 1 is a diagram showing the simulation result of the relationship between the first corona discharge angle θ1 and the luminous area of ​​ultraviolet light. The luminous area is the luminous area near the dielectric tube 61 and the first end 65a. The simulation result is obtained by calculating the electric field intensity near the dielectric tube 61 and the first end 65a. In the simulation, the potential of the inner electrode 63 is set to -3kV, the potential of the outer electrode 65 is set to 0V, and the area of ​​the region where the electric field intensity is above 3kV / mm is set to the luminous area of ​​ultraviolet light. The potential of the inner electrode 63 and the potential of the outer electrode 65 are typical values ​​for generating corona discharge near the dielectric tube 61 and the first end 65a. In addition, the value used to obtain Figure 7The potential of the inner electrode 63 and the potential of the outer electrode 65 of the simulation results shown can generate corona discharge, and there is no particular limitation. The gas pressure in the cavity 131 of the present embodiment is more than 220kPa and less than 280kPa, and the potential of the outer electrode 65 at the beginning of the corona discharge in this case is -3kV. In addition, it is considered that the potential of the outer electrode 65 at the beginning of the corona discharge when the gas pressure is more than 200kPa and less than 420kPa is also -3kV. And, under such gas pressure, it is considered that the area with an electric field intensity of more than 3kV / mm is the area where the corona discharge is initially generated. The intensity of the ultraviolet light generated from this area is high, and when the area of ​​the area, i.e., the luminous area, is large, the light amount of the ultraviolet light increases, and the pre-ionization intensity increases.

[0111] Figure 7 The horizontal axis shows the size of the first corona discharge angle θ1, and the vertical axis shows the luminous area. The luminous area is a relative value. The sizes of the first corona discharge angle θ1 are 30°, 60°, 90°, and 120°, and the luminous areas are 1.18, 0.79, 0.60, and 0.52. For example, in the comparative example, the first corona discharge angle θ1 is 131° and the luminous area is 0.49. In the present embodiment, the first corona discharge angle θ1 is 65° and the luminous area is 0.74. Therefore, the luminous area of ​​the present embodiment is about 1.5 times the luminous area of ​​the comparative example. According to Figure 7 The simulation results shown show that when the first corona discharge angle θ1 becomes smaller, the light emitting area becomes larger and the pre-ionization intensity becomes higher.

[0112] Figure 8 : is a diagram showing the simulation result of the relationship between the angle α and the first corona discharge angle θ1 of the present embodiment. Figure 8 In the example, the distance x1 is 19.0 mm, the distance y1 is 9.7 mm, and the radius r is 7.0 mm. Figure 8 , the range between the dotted line representing the first corona discharge angle θ1 and the line indicating 90° for the first corona discharge angle θ1 is the following range: the first end 65a does not block the ultraviolet light generated from the dielectric tube 61 and the vicinity of the first end 65a, the ultraviolet light enters the space S between the electrode 133a and the electrode 133b, and the pre-ionization intensity converges to the preferred intensity of this embodiment. Below, this range is sometimes referred to as simply the preferred range. In addition, the range below the dotted line representing the first corona discharge angle θ1 is the range where the first end 65a is located closer to the electrode 133b than the third straight line L3 and blocks a portion of the ultraviolet light. When the angle α is less than 0°, the dielectric tube 61 blocks a portion of the ultraviolet light. Figure 8In the figure, for easy observation, the preferred range, the obtuse angle range, and the light shielding range are recorded separately from the dotted line representing the first corona discharge angle θ1, the line showing 0°, 90°, and 120° of the first corona discharge angle θ1, and the line showing 0° and 30° of the angle α. The above values ​​of the distance x1, the distance y1, and the radius r are typical values ​​where the pre-ionization intensity converges to the preferred intensity. In addition, for obtaining Figure 8 The values ​​of the distance x1, the distance y1, and the radius r in the simulation results shown are not particularly limited.

[0113] Fig. 9 It is shown Figure 8 The relationship between the angle α and the first corona discharge angle θ1 in the preferred range and the relationship between the angle α and the pre-ionization intensity are shown in FIG. Fig. 9 It can be seen that when the angle α becomes smaller, the first corona discharge angle θ1 becomes smaller. In addition, it can be seen that when the first corona discharge angle θ1 becomes smaller, Figure 6 As shown, the luminous area becomes larger, and therefore, the pre-ionization intensity becomes higher. Therefore, in this embodiment, the smaller the angle α is, the higher the pre-ionization intensity is. In this embodiment, the angle α is less than 28°. In addition, when the angle α is 0°, the first corona discharge angle θ1 is 55°.

[0114] Fig.10 It is shown Figure 8 1 and 2 are graphs showing the relationship between angle α and the first corona discharge angle θ1 when the first corona discharge angle θ1 is 90°, and the relationship between angle α and pre-ionization intensity. It can be seen that when the first corona discharge angle θ1 is 90°, the pre-ionization intensity is substantially constant regardless of the size of angle α, and angle α has little effect on the pre-ionization intensity.

[0115] 3.2 Effects

[0116] When a high voltage is applied between the inner electrode 63 and the outer electrode 65, a corona discharge is generated near the dielectric tube 61 and the first end 65a, and ultraviolet light is radiated. When the ultraviolet light irradiates the laser gas between the electrode 133a and the electrode 133b, the laser gas between the electrode 133a and the electrode 133b is pre-ionized. After the pre-ionization, when the voltage between the electrode 133a and the electrode 133b reaches the insulation breakdown voltage, the main discharge between the electrode 133a and the electrode 133b is generated. However, in the cavity 131 of the present embodiment, the first corona discharge angle θ1 is an acute angle. According to this structure, compared with the case where the first corona discharge angle θ1 is an obtuse angle, the light emitting area of ​​the ultraviolet light between the dielectric tube 61 and the first end 65a can be increased, and the light amount of the ultraviolet light can be increased. As a result, the pre-ionization intensity can be increased, and the decrease in the stability of the laser emitted from the gas laser device 100 can be suppressed. Therefore, the laser that meets the required performance can be emitted from the exposure device 200.

[0117] In addition, the preionization electrode 60 of the present embodiment may be arranged on the downstream side of the laser gas flowing between the electrode 133a and the electrode 133b along the X direction, closer to the electrode 133a. In addition, in the present embodiment, the first main electrode is the electrode 133a, the second main electrode is the electrode 133b, and the preionization electrode 60 is arranged on the side of the electrode 133a serving as the first main electrode. However, it is also possible that the first main electrode is the electrode 133b, the second main electrode is the electrode 133a, and the preionization electrode 60 may be arranged on the side of the electrode 133b serving as the first main electrode. In addition, if the first corona discharge angle θ1 is an acute angle, equations (1), (2), (3), and (4) may not hold true.

[0118] Fig.11 This is a diagram of the periphery of the preionization electrode 60 in a variation of the present embodiment observed along the Z direction. In the preionization electrode 60 of the present variation, the configuration position of the preionization electrode 60 is different from that of the first embodiment. The preionization electrode 60 of the present variation is disposed on one side of the electrode 133b, which is the second main electrode, in the X direction. The first corona discharge angle θ1 of the present variation is also an acute angle as in the first embodiment. The preionization electrode 60 of the present variation is also disposed on the upstream side of the laser gas flowing along the X direction between the electrode 133a and the electrode 133b. Fig.11 In FIG. 1 , the flow of the laser gas is shown by bold arrows.

[0119] The first guide 67 of this modification is fixed to the electrode 133b on the surface of the electrical insulating portion 135 on the inner space side of the cavity 131. Therefore, the external electrode 65 is fixed to the electrode 133b via the first guide 67. Alternatively, the external electrode 65 may be directly fixed to the electrode 133b.

[0120] Fig.12 This is a circuit diagram of the chamber 131 of a modified example of this embodiment. The outer electrode 65 is electrically connected to the electrode 133b and the pulse power module 143. The inner electrode 63 is electrically connected to one end of the pre-ionization capacitor 31b via the current introduction terminal 31c. The pre-ionization capacitor 31b is connected to the ground potential.

[0121] In this modification, a voltage is applied between the outer electrode 65 and the inner electrode 63 so that the potential of the outer electrode 65 is lower than that of the inner electrode 63, so that the fluorine ions move toward the inner electrode 63 side, that is, the dielectric tube 61 side. Therefore, the corrosion of the outer electrode 65 due to the fluorine ions can be suppressed.

[0122] In addition, the preionization electrode 60 of the present modification may be arranged on the downstream side of the laser gas flowing in the X direction between the electrode 133 a and the electrode 133 b rather than the electrode 133 b .

[0123] 4. Description of the cavity of Embodiment 2

[0124] Next, the cavity 131 of Embodiment 2 is described. In addition, the same reference numerals are given to the same structures as those described above, and repeated descriptions are omitted except for special descriptions. In addition, in some drawings, a part of the components is sometimes omitted or briefly described for easy viewing.

[0125] 4.1 Structure

[0126] Fig.13 2 is a diagram showing the periphery of the preionization electrode 60 in the present embodiment as viewed along the Z direction. Fig.13 In FIG. 1 , the flow of the laser gas is shown by bold arrows.

[0127] In the outer electrode 65 of the present embodiment, the configuration position of the outer electrode 65 is different from that of the first embodiment. The outer electrode 65 of the present embodiment is fixed to the opposite side of the electrode 133a with respect to the dielectric tube 61, which is different from the first embodiment. The outer electrode 65 is fixed to the guide 67a, which is provided on the upstream side of the outer electrode 65, by screwing a screw (not shown) into the threaded hole of the outer electrode 65. The guide 67a is a conductor fixed to the electrode holder portion 137. The guide 67a guides the laser gas so that the laser gas from the cross flow fan 149 flows between the electrode 133a and the electrode 133b. As the material of the guide 67a, the same material as the first guide 67 can be cited. In addition, the guide 67a may not be provided.

[0128] Fig.14 yes Fig.13 The first corona discharge angle θ1 of this embodiment is an acute angle similar to that of the first embodiment. Fig.14 In the figure, the guide 18 is omitted.

[0129] exist Fig.14 In FIG. 1 , the surface of the electrode 133b facing the electrode 133a is represented as the second facing surface 134b. Fig.14 In , the distance in the separation direction from the first straight line L1 to the second opposing surface 134b is represented by y2. In addition, the distance from the center C of the dielectric tube 61 to the side surface on the upstream side of the electrode 133b in the direction perpendicular to the Z direction and the separation direction is represented by x2. The dielectric tube 61 of this embodiment is arranged so that the following equations (5) and (6) are satisfied.

[0130] y2≥r···(5)

[0131] x2>r···(6)

[0132] In this embodiment, Fig.14 In the figure, the angle between the first straight line L1 and the second straight line L2 is represented by α. In addition, the angle between the fourth straight line L4 in the plane perpendicular to the Z direction and the first straight line L1 is represented by β2, and the fourth straight line L4 passes through the center C of the dielectric tube 61 and the edge of the second opposing surface 134b on the dielectric tube 61 side. The angle β2 is an acute angle. In the cavity 131 of this embodiment, the following equations (7) and (8) are established.

[0133] β2<α<90°···(7)

[0134] (90°-α+tan -1 ((y2-rsinα) / (x2-rcosα)))≤θ1<90°···(8)

[0135] Fig.15 : is a diagram showing the simulation result of the relationship between the angle α and the first corona discharge angle θ1 of the present embodiment. Fig.15 In the example, the distance x2 is 19.0 mm, the distance y2 is 25.7 mm, and the radius r is 7.0 mm. Fig.15 , the range between the dotted line representing the first corona discharge angle θ1 and the line indicating 90° for the first corona discharge angle θ1 is the following range: the first end 65a does not block the ultraviolet light generated from the dielectric tube 61 and the vicinity of the first end 65a, the ultraviolet light enters the space S between the electrode 133a and the electrode 133b, and the pre-ionization intensity converges to the preferred intensity of this embodiment. Hereinafter, this range is sometimes referred to as simply the preferred range. In addition, the range below the dotted line representing the first corona discharge angle θ1 is the range where the first end 65a is located closer to the electrode 133a side than the fourth straight line L4 and blocks a portion of the ultraviolet light. When the angle α is greater than 90°, the dielectric tube 61 blocks a portion of the ultraviolet light. Fig.15 In the figure, for easy observation, the preferred range, the obtuse angle range, and the light shielding range are described separately from the dotted line representing the first corona discharge angle θ1, the line representing the first corona discharge angle θ1 showing 0°, 90°, and 120°, and the line representing the angle α showing 50° and 90°. The above values ​​of the distance x2, the distance y2, and the radius r are typical values ​​that produce a range in which the pre-ionization intensity becomes a preferred intensity. In addition, for obtaining Fig.15 The values ​​of the distance x2, the distance y2, and the radius r in the simulation results shown are not particularly limited.

[0136] Fig.16 It is shown Fig.15 The relationship between the angle α and the first corona discharge angle θ1 in the preferred range and the relationship between the angle α and the pre-ionization intensity are shown in FIG. Fig.16It can be seen that when the angle α increases, the first corona discharge angle θ1 decreases. It can be seen that when the first corona discharge angle θ1 decreases, Figure 7 As shown, the light emitting area becomes larger, and therefore, the pre-ionization intensity becomes higher. Therefore, in this embodiment, the larger the angle α is, the higher the pre-ionization intensity is. In this embodiment, the angle α is greater than 53° and less than 90°.

[0137] Fig.17 It is shown Fig.15 1 and 2 are graphs showing the relationship between angle α and the first corona discharge angle θ1 when the first corona discharge angle θ1 is 90°, and the relationship between angle α and pre-ionization intensity. It can be seen that when the first corona discharge angle θ1 is 90°, the pre-ionization intensity is substantially constant regardless of the size of angle α, and angle α has little effect on the pre-ionization intensity.

[0138] 4.2 Effects

[0139] Even though the outer electrode 65 is different from the first embodiment and is provided on the opposite side of the electrode 133a with respect to the dielectric tube 61, the first corona discharge angle θ1 of the present embodiment is an acute angle. According to this structure, compared with the case where the first corona discharge angle θ1 is an obtuse angle, the light emitting area of ​​the ultraviolet light between the dielectric tube 61 and the first end 65a can be increased, and the light amount of the ultraviolet light can be increased. Thus, the pre-ionization intensity can be increased, and the decrease in the stability of the laser light emitted from the gas laser device 100 can be suppressed. Therefore, the laser light satisfying the required performance can be emitted from the exposure device 200.

[0140] In addition, the preionization electrode 60 of this embodiment may be arranged on the downstream side of the laser gas flowing between the electrodes 133a and 133b in the X direction relative to the electrode 133a. In addition, if the first corona discharge angle θ1 is an acute angle, equations (5), (6), (7), and (8) may not hold.

[0141] 5. Description of the cavity of Embodiment 3

[0142] Next, the cavity 131 of Embodiment 3 is described. In addition, the same reference numerals are given to the same structures as those described above, and repeated descriptions are omitted except for special descriptions. In addition, in some drawings, a part of the components is sometimes omitted or briefly described for easy viewing.

[0143] 5.1 Structure

[0144] Fig.181 is a diagram of the periphery of the preionization electrode in the present embodiment observed along the Z direction. In the cavity 131 of the present embodiment, one preionization electrode is added to the embodiment 1, which is different from the embodiment 1. Below, for the sake of convenience, the added preionization electrode is described as the second preionization electrode. In addition, the second preionization electrode is sometimes referred to as the preionization electrode 70. The preionization electrode 70 has the same structure as the preionization electrode 60 in the modified example of the embodiment 1, and only the label is changed.

[0145] For ease of explanation, the components in the pre-ionization electrode 70 are respectively described as the second dielectric tube, the second pre-ionization inner electrode, the second pre-ionization outer electrode and the second end, and are sometimes respectively referred to as the dielectric tube 71, the inner electrode 73, the outer electrode 75 and the second end 75a.

[0146] The preionization electrode 70 is provided at a position facing the preionization electrode 60 on the side of the electrode 133b. The preionization electrodes 60 and 70 are arranged on the upstream side of the laser gas flowing in the X direction between the electrode 133a and the electrode 133b. Fig.18 In FIG. 1 , the flow of the laser gas is shown by bold arrows.

[0147] In addition, the tangent, straight line and corona discharge angle in the pre-ionization electrode 70 are sometimes referred to as the second tangent 42a, straight line 42b and second corona discharge angle θ2, respectively. The second tangent 42a and the second corona discharge angle θ2 are equivalent to the first tangent 41a, straight line 41b and first corona discharge angle θ1 in the modified example of the first embodiment, and only the names and numbers are changed. The pre-ionization electrode 70 has the same structure as the pre-ionization electrode 60, and therefore, the second corona discharge angle θ2 of this embodiment is an acute angle as well as the first corona discharge angle θ1. In addition, the second corona discharge angle θ2 is an angle toward the space S between the electrode 133a and the electrode 133b in the plane perpendicular to the Z direction and formed by the second tangent 42a and the straight line 42b. That is, the second corona discharge angle θ2 is an angle on the side where the laser gas between the electrode 133a and the electrode 133b is pre-ionized. The second tangent line 42a is a straight line that is tangent to the dielectric tube 71 at the second predetermined position P2 closest to the second end 75a in the dielectric tube 71. The straight line 42b is a line that passes through the second predetermined position P2 and extends in the direction in which the external electrode 75 extends from the second end 75a. In this embodiment, equations (1), (2), (3), and (4) also hold true.

[0148] A second guide 77 having the same structure as the first guide 67 of the modification of Embodiment 1 is disposed on the surface of the electrical insulating portion 135 on the inner space side of the cavity 131. Therefore, the external electrode 75 is fixed to the electrode 133b via the second guide 77. Alternatively, the external electrode 75 may be directly fixed to the electrode 133b.

[0149] A pair of holders (not shown) having the same structure as the holders on the dielectric tube 61 side are provided on the surface of the electrical insulating portion 135 on the inner space side of the cavity 131 in the present embodiment. In the same manner as the pair of holders on the dielectric tube 61 side hold the dielectric tube 61, one end side of the dielectric tube 71 is inserted into the hole of the holder (not shown) and held by the holder, and the other end side of the dielectric tube 71 is inserted into the hole of the holder (not shown) and held by the holder.

[0150] One end of each of the internal electrodes 63 and 73 is electrically connected to each other through an internal electrode connector (not shown). In addition, the other ends of each of the internal electrodes 63 and 73 can also be electrically connected to each other through an internal electrode connector. The internal electrode connector is cylindrical, but can also be linear. The other end of the external electrode 75 is electrically connected to the electrode 133b.

[0151] Fig.19 1 is a circuit diagram in the cavity 131 of the present embodiment. In the circuit diagram of the present embodiment, the pre-ionization capacitor 31b and the current introduction terminal 31c are not configured, which is different from the circuit diagram of the comparative example. When the switch 143a is turned on, the charge accumulated in the charging capacitor is transferred to the peaking capacitor 31a, and at the same time, the voltage between the electrode 133a and the electrode 133b rises. In addition, a voltage half of the voltage between the electrode 133a and the electrode 133b is induced in the inner electrodes 63 and 73, respectively. As a result, corona discharge is generated near the dielectric tube 61 and the first end 65a and near the dielectric tube 71 and the second end 75a, and ultraviolet light is radiated respectively. When the ultraviolet light irradiates the laser gas between the electrode 133a and the electrode 133b, the laser gas between the electrode 133a and the electrode 133b is pre-ionized. After pre-ionization, when the voltage between the electrodes 133a and 133b reaches the insulation breakdown voltage, a main discharge occurs between the electrodes 133a and 133b. As a result, excimer molecules are generated from the laser medium contained in the laser gas between the electrodes 133a and 133b, and emit light when dissociated.

[0152] 5.2 Effects

[0153] According to this structure, compared with the case where the second corona discharge angle θ2 is an obtuse angle, the light emitting area of ​​the ultraviolet light between the dielectric tube 71 and the second end 75a can be increased, and the light amount of the ultraviolet light can be increased. As a result, the pre-ionization intensity can be increased, and the decrease in the stability of the laser emitted from the gas laser device 100 can be suppressed. Therefore, the laser that meets the required performance can be emitted from the exposure device 200. In addition, according to this structure, compared with the case where either one of the pre-ionization electrodes 60 and 70 is provided, the pre-ionization intensity can be increased.

[0154] 6. Description of the Cavity of Embodiment 4

[0155] Next, the cavity 131 of Embodiment 4 is described. In addition, the same reference numerals are given to the same structures as those described above, and repeated descriptions are omitted except for special descriptions. In addition, in some drawings, a part of the components is sometimes omitted or briefly described for easy viewing.

[0156] 6.1 Structure

[0157] Fig. 20 This is a diagram of the periphery of the preionization electrodes 60 and 70 in the present embodiment as viewed along the Z direction.

[0158] The chamber 131 of this embodiment is different from Embodiment 3 in that two preionization electrodes are further added to Embodiment 3. For ease of explanation, the two added preionization electrodes are described as the third preionization electrode and the fourth preionization electrode, and are sometimes referred to as the preionization electrode 80 and the preionization electrode 90.

[0159] The preionization electrodes 80 and 90 have the same structure as the preionization electrode 60 . The preionization electrode 80 is arranged on the side of the electrode 133 a , and the preionization electrode 90 is arranged on the side of the electrode 133 b .

[0160] For the sake of convenience, the components of the preionization electrode 80 are respectively described as the third dielectric tube, the third preionization inner electrode, the third preionization outer electrode, and the third end, and are sometimes referred to as the dielectric tube 81, the inner electrode 83, the outer electrode 85, and the third end 85a. In addition, the components of the preionization electrode 90 are respectively described as the fourth dielectric tube, the fourth preionization inner electrode, the fourth preionization outer electrode, and the fourth end, and are sometimes referred to as the dielectric tube 91, the inner electrode 93, the outer electrode 95, and the fourth end 95a.

[0161] The preionization electrode 80 is disposed on the other side of the electrode 133a in the X direction, that is, on the side opposite to the preionization electrode 60. In addition, the preionization electrode 90 is disposed at a position facing the preionization electrode 80 on the other side of the electrode 133b, that is, on the side opposite to the preionization electrode 70. The preionization electrode 80 and the preionization electrode 90 are arranged on the downstream side of the laser gas flowing in the X direction between the electrode 133a and the electrode 133b. Fig. 20 In FIG. 1 , the flow of the laser gas is shown by bold arrows.

[0162] In addition, sometimes the tangent, straight line and corona discharge angle in the preionization electrode 80 are respectively referred to as the third tangent 43a, straight line 43b and the third corona discharge angle θ3, and the tangent, straight line and corona discharge angle in the preionization electrode 90 are respectively referred to as the fourth tangent 44a, straight line 44b and the fourth corona discharge angle θ4. The preionization electrode 80 is a component obtained by reversing the preionization electrode 60 based on the electrode 133a, and the preionization electrode 90 is a component obtained by reversing the preionization electrode 70 based on the electrode 133b. The preionization electrodes 80 and 90 have the same structure as the preionization electrode 60, and therefore, the third corona discharge angle θ3 and the fourth corona discharge angle θ4 of the present embodiment are acute angles like the first corona discharge angle θ1. In addition, the third corona discharge angle θ3 is an angle toward the space S between the electrode 133a and the electrode 133b in the plane perpendicular to the Z direction, among the angles formed by the third tangent line 43a and the straight line 43b. The fourth corona discharge angle θ4 is an angle toward the space S between the electrode 133a and the electrode 133b in the plane perpendicular to the Z direction, among the angles formed by the fourth tangent line 44a and the straight line 44b. That is, the corona discharge angles θ3 and θ4 are angles on the side where the laser gas between the electrode 133a and the electrode 133b is pre-ionized. The third tangent line 43a is a straight line that is tangent to the dielectric tube 81 at the third predetermined position P3 closest to the third end 85a in the dielectric tube 81. The straight line 43b is a line that passes through the third predetermined position P3 and extends in the direction in which the outer electrode 85 extends from the third end 85a. The fourth tangent line 44a is a straight line that is tangent to the dielectric tube 91 at the fourth predetermined position P4 closest to the fourth end 95a in the dielectric tube 91. The straight line 44b is a line that passes through the fourth predetermined position P4 and extends in the direction in which the external electrode 95 extends from the fourth end 95a. In this embodiment, the equations (1), (2), (3), and (4) also hold true.

[0163] The electrode holder portion 137 of the present embodiment is provided with a third guide 87 having the same structure as the first guide 67 and fixed to the electrode 133a. In addition, a fourth guide 97 having the same structure as the second guide 77 and fixed to the electrode 133b is provided on the surface of the electrical insulating portion 135 on the inner space side of the cavity 131. The external electrodes 85 and 95 are fixed to the guides 87 and 97 separately, similarly to the fixing of the external electrodes 65 and 75 to the guides 67 and 77. Therefore, the external electrode 85 is fixed to the electrode 133a via the third guide 87, and the external electrode 95 is fixed to the electrode 133b via the fourth guide 97. In addition, the external electrode 85 may be directly fixed to the electrode 133a, and the external electrode 95 may be directly fixed to the electrode 133b.

[0164] A pair of holders holding the dielectric tube 61 of the present embodiment extend in the X direction, respectively, and include holes (not shown) on the upstream and downstream sides of the flow of the laser gas. One end of the dielectric tube 61 is inserted into the hole on the upstream side of one holder, and one end of the dielectric tube 81 is inserted into the hole on the downstream side of one holder. Thus, one end of the dielectric tube 61 and one end of the dielectric tube 81 are held by one holder. In addition, the other end of the dielectric tube 61 is inserted into the hole on the upstream side of the other holder, and the other end of the dielectric tube 81 is inserted into the hole on the downstream side of the other holder. Thus, the other end of the dielectric tube 61 and the other end of the dielectric tube 81 are held by the other holder.

[0165] A pair of holders holding the dielectric tube 71 of the present embodiment extend in the X direction, respectively, and include holes (not shown) on the upstream and downstream sides of the flow of the laser gas. One end of the dielectric tube 71 is inserted into the hole on the upstream side of one holder, and one end of the dielectric tube 91 is inserted into the hole on the downstream side of the other holder. Thus, one end of the dielectric tube 71 and one end of the dielectric tube 91 are held by one holder. In addition, the other end of the dielectric tube 71 is inserted into the hole on the upstream side of the other holder, and the other end of the dielectric tube 91 is inserted into the hole on the downstream side of the other holder. Thus, the other end of the dielectric tube 71 and the other end of the dielectric tube 91 are held by the other holder.

[0166] One end of each of the internal electrodes 83 and 93 is electrically connected to each other through an internal electrode connector having the same structure as the internal electrode connectors in the internal electrodes 63 and 73. In addition, the other ends of each of the internal electrodes 83 and 93 can also be electrically connected to each other through the internal electrode connector. The other end of the external electrode 85 is electrically connected to the electrode 133a via the electrode holder portion 137, and is electrically connected to the cavity 131 via the electrode holder portion 137 and the wiring 137a. The external electrode 85, the electrode holder portion 137, the wiring 137a, and the cavity 131 are at the ground potential. The other end of the external electrode 95 is electrically connected to the electrode 133b.

[0167] Fig.211 is a circuit diagram in the cavity 131 of the present embodiment. When the switch 143a is turned on, the charge accumulated in the charging capacitor is transferred to the peaking capacitor 31a, and at the same time, the voltage between the electrode 133a and the electrode 133b increases. In addition, a voltage half of the voltage between the electrode 133a and the electrode 133b is induced in the inner electrodes 63, 73, 83, and 93, respectively. As a result, corona discharge is generated near the dielectric tube 61 and the first end 65a, near the dielectric tube 71 and the second end 75a, near the dielectric tube 81 and the third end 85a, and near the dielectric tube 91 and the fourth end 95a, and ultraviolet light is radiated. When the ultraviolet light irradiates the laser gas between the electrode 133a and the electrode 133b, the laser gas between the electrode 133a and the electrode 133b is pre-ionized. Then, the main discharge between the electrode 133a and the electrode 133b is generated. As a result, excimer molecules are generated from the laser medium contained in the laser gas between the electrode 133 a and the electrode 133 b , and emit light when dissociated.

[0168] 6.2 Action / Effect

[0169] According to this structure, compared with the case where the corona discharge angles θ3 and θ4 are obtuse angles, the light emitting area of ​​ultraviolet light between the dielectric tube 81 and the third end 85a and the light emitting area of ​​ultraviolet light between the dielectric tube 91 and the fourth end 95a can be increased, and the light quantity of ultraviolet light can be increased. As a result, the pre-ionization intensity can be increased, and the decrease in the stability of the laser light emitted from the gas laser device 100 can be suppressed. Therefore, the laser light that meets the required performance can be emitted from the exposure device 200. In addition, according to this structure, compared with the case where any one of the pre-ionization electrodes 60, 70, 80, and 90 is provided, the pre-ionization intensity can be increased.

[0170] In addition, in the chamber 131 of the present embodiment, any one of the four pre-ionization electrodes 60 , 70 , 80 , and 90 may not be disposed.

[0171] The above description is not limiting but simply illustrative. Therefore, those skilled in the art will appreciate that changes can be made to the embodiments of the present disclosure without departing from the claims. In addition, those skilled in the art will appreciate that the embodiments of the present disclosure can be used in combination.

[0172] Unless explicitly stated otherwise, the terms used in this specification and claims as a whole should be interpreted as "non-limiting" terms. For example, terms such as "including", "having", "having", and "having" should be interpreted as "excluding the presence of structural elements other than the structural elements to be recorded". In addition, the modifier "one" should be interpreted as meaning "at least one" or "one 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 further, should be interpreted as also including combinations of them and parts other than "A", "B", and "C".

Claims

1. A cavity of a gas laser device, wherein a laser gas is sealed in an internal space, wherein: The cavity has: a first main electrode and a second main electrode, the length directions of which are along a predetermined direction, and which are spaced apart from each other and face each other in the internal space; a window disposed on a wall of the cavity, through which light from the interior space passes; and a first pre-ionization electrode, which is disposed on one side of the first main electrode, The first preionization electrode comprises a first dielectric tube extending along the length direction, a first preionization inner electrode arranged inside the first dielectric tube and extending along the length direction, and a first preionization outer electrode extending along the length direction, the first preionization outer electrode comprising a first end portion facing the outer peripheral surface of the first dielectric tube and extending from the first end portion in a direction away from the first dielectric tube, In a plane perpendicular to the longitudinal direction, a first corona discharge angle toward the space between the first main electrode and the second main electrode among the angles formed by a first tangent and a straight line is an acute angle, wherein the first tangent is tangent to the first dielectric tube at a first prescribed position closest to the first end in the first dielectric tube, and the straight line passes through the first prescribed position and extends in a direction in which the first preionization outer electrode extends from the first end.

2. The cavity of the gas laser device according to claim 1, wherein: Assuming the radius of the first dielectric tube is r, When the distance in the separation direction from a first straight line that is orthogonal to the separation direction of the first main electrode and the second main electrode and passes through the center of the first dielectric tube to a first opposing surface of the first main electrode facing the second main electrode in a plane perpendicular to the longitudinal direction is y1, the following equation holds true: y1≥r。 3. The cavity of the gas laser device according to claim 2, wherein: The first pre-ionization outer electrode is disposed between the first main electrode and the first dielectric tube. Assuming that the angle formed by the second straight line passing through the first predetermined position and the center of the first dielectric tube and the first straight line in a plane perpendicular to the longitudinal direction is α, Assuming that the angle formed by a third straight line passing through the center of the first dielectric tube and the edge of the first opposing surface on the first dielectric tube side in a plane perpendicular to the longitudinal direction and the first straight line is β1, The following formula holds 0≤α＜β1。 4. The cavity of the gas laser device according to claim 3, wherein: Let x1 be the distance from the center of the first dielectric tube to the first main electrode in a direction perpendicular to the longitudinal direction and the separation direction, Assuming the first corona discharge angle is θ1, The following formula holds 90°+α-tan -1 ((y1-rsina) / (x1-rcosa)))≤θ1<90°。 5. The cavity of the gas laser device according to claim 2, wherein: The first pre-ionization outer electrode is fixed on the opposite side of the first main electrode with respect to the first dielectric tube. The second main electrode includes a second opposing surface opposed to the first main electrode. Assuming that the angle formed by the second straight line passing through the first predetermined position and the center of the first dielectric tube and the first straight line in a plane perpendicular to the longitudinal direction is α, Assuming that the angle formed by a fourth straight line passing through the center of the first dielectric tube and the edge of the second opposing surface on the first dielectric tube side in a plane perpendicular to the longitudinal direction and the first straight line is β2, The following formula holds β2＜α＜90°。 6. The cavity of the gas laser device according to claim 5, wherein: Let y2 be the distance in the separation direction from the first straight line to the second opposing surface in a plane perpendicular to the longitudinal direction, Assuming that the distance from the center of the first dielectric tube to the second main electrode in a direction perpendicular to the longitudinal direction and the separation direction is x2, Assuming the first corona discharge angle is θ1, The following formula holds (90°-α+tan -1 ((y2-rsina) / (x2-rcosa)))≤θ1<90°。 7. The cavity of the gas laser device according to claim 1, wherein: The chamber further comprises a second pre-ionization electrode, which is disposed on the one side of the second main electrode at a position opposite to the first pre-ionization electrode. The second preionization electrode comprises a second dielectric tube extending along the longitudinal direction, a second preionization inner electrode arranged inside the second dielectric tube and extending along the longitudinal direction, and a second preionization outer electrode extending along the longitudinal direction, the second preionization outer electrode comprising a second end portion facing the outer peripheral surface of the second dielectric tube and extending from the second end portion in a direction away from the second dielectric tube, In a plane perpendicular to the longitudinal direction, a first corona discharge angle toward the space between the first main electrode and the second main electrode among the angles formed by a second tangent line and a straight line that is tangent to the second dielectric tube at a second prescribed position closest to the second end in the second dielectric tube, and that passes through the second prescribed position and extends in a direction in which the second preionization outer electrode extends from the second end, is an acute angle.

8. The cavity of the gas laser device according to claim 7, wherein: The first pre-ionization inner electrode is electrically connected to the second pre-ionization inner electrode, The first pre-ionization outer electrode is electrically connected to the first main electrode, The second pre-ionization outer electrode is electrically connected to the second main electrode.

9. The cavity of the gas laser device according to claim 7, wherein: The cavity also has: a third pre-ionization electrode, which is disposed on the other side of the first main electrode; and a fourth pre-ionization electrode provided on the other side of the second main electrode at a position opposing the third pre-ionization electrode, The third preionization electrode comprises a third dielectric tube extending along the length direction, a third preionization inner electrode arranged inside the third dielectric tube and extending along the length direction, and a third preionization outer electrode extending along the length direction, the third preionization outer electrode comprising a third end portion facing the outer peripheral surface of the third dielectric tube and extending from the third end portion in a direction away from the third dielectric tube, The fourth preionization electrode comprises a fourth dielectric tube extending along the longitudinal direction, a fourth preionization inner electrode arranged inside the fourth dielectric tube and extending along the longitudinal direction, and a fourth preionization outer electrode extending along the longitudinal direction, the fourth preionization outer electrode including a fourth end portion facing the outer peripheral surface of the fourth dielectric tube and extending from the third end portion in a direction away from the fourth dielectric tube, In a plane perpendicular to the longitudinal direction, a third corona discharge angle toward the space between the first main electrode and the second main electrode among angles formed by a third tangent line and a straight line that is tangent to the third dielectric tube at a third predetermined position closest to the third end in the third dielectric tube, the straight line passing through the third predetermined position and extending in a direction in which the third preionization outer electrode extends from the third end, is an acute angle, In a plane perpendicular to the longitudinal direction, a fourth corona discharge angle toward the space between the first main electrode and the second main electrode is an acute angle among the angles formed by the fourth tangent and the following straight line, wherein the fourth tangent is tangent to the fourth dielectric tube at a fourth prescribed position closest to the fourth end in the fourth dielectric tube, and the straight line passes through the fourth prescribed position and extends in the direction in which the fourth preionization outer electrode extends from the fourth end.

10. The cavity of the gas laser device according to claim 9, wherein: The first pre-ionization inner electrode is electrically connected to the second pre-ionization inner electrode, The third pre-ionization inner electrode is electrically connected to the fourth pre-ionization inner electrode, The first pre-ionization outer electrode and the third pre-ionization outer electrode are electrically connected to the first main electrode. The second pre-ionization outer electrode and the fourth pre-ionization outer electrode are electrically connected to the second main electrode.

11. A gas laser device having a cavity in which a laser gas is sealed, wherein: The cavity has: a first main electrode and a second main electrode, the length directions of which are along a predetermined direction, and which are spaced apart from each other and face each other in the internal space; a window disposed on a wall of the cavity, through which light from the interior space passes; and a first pre-ionization electrode, which is disposed on one side of the first main electrode, The first preionization electrode comprises a first dielectric tube extending along the length direction, a first preionization inner electrode arranged inside the first dielectric tube and extending along the length direction, and a first preionization outer electrode extending along the length direction, the first preionization outer electrode comprising a first end portion facing the outer peripheral surface of the first dielectric tube and extending from the first end portion in a direction away from the first dielectric tube, In a plane perpendicular to the longitudinal direction, a first corona discharge angle toward the space between the first main electrode and the second main electrode among the angles formed by a first tangent line and a straight line that is tangent to the first dielectric tube at a first prescribed position closest to the first end in the first dielectric tube, and that passes through the first prescribed position and extends in a direction in which the first preionization outer electrode extends from the first end, is an acute angle.

12. The gas laser device according to claim 11, wherein: The gas pressure in the chamber is greater than or equal to 200 kPa and less than or equal to 420 kPa.

13. A method for manufacturing an electronic device, comprising the following steps: The laser is generated by a gas laser device. outputting the laser to an exposure device, The laser is exposed on a photosensitive substrate in the exposure device to manufacture an electronic device. The cavity of the gas laser device seals laser gas in the internal space. The cavity has: a first main electrode and a second main electrode, the length directions of which are along a predetermined direction, and which are spaced apart from each other and face each other in the internal space; a window disposed on a wall of the cavity, through which light from the interior space passes; and a first pre-ionization electrode, which is disposed on one side of the first main electrode, The first preionization electrode comprises a first dielectric tube extending along the length direction, a first preionization inner electrode arranged inside the first dielectric tube and extending along the length direction, and a first preionization outer electrode extending along the length direction, the first preionization outer electrode comprising a first end portion facing the outer peripheral surface of the first dielectric tube and extending from the first end portion in a direction away from the first dielectric tube, In a plane perpendicular to the longitudinal direction, a first corona discharge angle toward the space between the first main electrode and the second main electrode among the angles formed by a first tangent line and a straight line that is tangent to the first dielectric tube at a first prescribed position closest to the first end in the first dielectric tube, and that passes through the first prescribed position and extends in a direction in which the first preionization outer electrode extends from the first end, is an acute angle.

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