Laser chamber, gas laser apparatus, and method for manufacturing electronic device

Abstract

A laser chamber, a gas laser apparatus, and a method of manufacturing an electronic device are provided. A laser chamber according to one aspect of the present disclosure is a laser chamber of a gas laser device that outputs laser light, and is provided with: a container filled with laser gas; a first electrode extending in a first direction and disposed inside the container; a second electrode extending in the first direction and disposed closer to the inner wall of the container than the first electrode in a state of facing the first electrode in a second direction orthogonal to the first direction; a fan that causes the laser gas to flow in a discharge space between the first electrode and the second electrode; an insulating guide disposed on the downstream side of the second electrode; and a vortex dividing member that divides a vortex generated by a portion of the flow of the laser gas, the plurality of structures extending in the first direction and being disposed discretely in the direction of the flow of the laser gas at a position downstream of the insulative guide, the vortex dividing member being configured from a plurality of structures that are disposed discretely in the direction of the flow of the laser gas.

Description

Technical Field

[0001] The invention relates to a laser chamber, a gas laser device and a method for manufacturing an electronic device. Background Art

[0002] In recent years, semiconductor exposure equipment has been required to achieve higher resolution as semiconductor integrated circuits become increasingly miniaturized and highly integrated. Consequently, there has been a trend toward shorter wavelengths of light emitted from exposure light sources. For example, gas laser devices used for exposure include KrF excimer lasers, which output laser light with a wavelength of approximately 248 nm, and ArF excimer lasers, which output laser light with a wavelength of approximately 193 nm.

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

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: U.S. Patent No. 6,442,181 Summary of the Invention

[0007] A laser chamber according to one aspect of the present disclosure is a laser chamber of a gas laser device that outputs laser light, comprising: a container filled with laser gas; a first electrode extending in a first direction and arranged in the container; a second electrode extending in the first direction and arranged at a position closer to the inner wall of the container than the first electrode so as to be opposite to the first electrode in a second direction orthogonal to the first direction; a fan that causes the laser gas to flow in a discharge space between the first electrode and the second electrode; an insulating guide arranged on the downstream side of the second electrode; and a vortex dividing component composed of a plurality of structures that divides a vortex generated by a portion of the flow of the laser gas, the plurality of structures extending in the first direction and discretely arranged along the direction of the laser gas flow at a position downstream of the insulating guide.

[0008] A gas laser device according to one aspect of the present disclosure outputs laser light and comprises: an optical resonator; and a laser chamber configured to allow an optical path of the optical resonator to pass through, wherein the laser chamber includes: a container filled with laser gas; a first electrode extending in a first direction and disposed in the container; a second electrode extending in the first direction and disposed at a position closer to the inner wall of the container than the first electrode so as to be opposed to the first electrode in a second direction orthogonal to the first direction; a fan for causing the laser gas to flow in a discharge space between the first electrode and the second electrode; an insulating guide disposed on the downstream side of the second electrode; and a vortex dividing component composed of a plurality of structures for dividing a vortex generated by a portion of the flow of the laser gas, the plurality of structures extending in the first direction and discretely disposed along the direction of the laser gas flow at a position downstream of the insulating guide.

[0009] According to one aspect of the present invention, a method for manufacturing an electronic device generates laser light by a gas laser device, outputs the laser light to an exposure device, and exposes the laser light to a photosensitive substrate in the exposure device to manufacture the electronic device. The gas laser device outputs laser light and is equipped with: an optical resonator; and a laser chamber configured so that an optical path of the optical resonator passes through. The laser chamber includes: a container filled with laser gas; a first electrode extending in a first direction and disposed in the container; a second electrode extending in the first direction and disposed at a position closer to the inner wall of the container than the first electrode so as to oppose the first electrode in a second direction orthogonal to the first direction; a fan for causing the laser gas to flow in a discharge space between the first and second electrodes; an insulating guide disposed downstream of the second electrode; and a vortex dividing component composed of a plurality of structures for dividing a vortex generated by a portion of the laser gas flow, the plurality of structures extending in the first direction and discretely disposed downstream of the insulating guide in the direction of laser gas flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings, merely as examples.

[0011] Figure 1 It is a side view schematically showing the structure of a gas laser device according to a comparative example.

[0012] Figure 2 It is a cross-sectional view schematically showing the structure of a gas laser device according to a comparative example.

[0013] Figure 3 This is a cross-sectional view showing in detail the structure near the main electrode of the laser cavity.

[0014] Figure 4 This is a cross-sectional view showing in detail the structure of the laser cavity near the main electrode according to the first embodiment.

[0015] Figure 5 This is a diagram showing an example of the flow of laser gas in the first embodiment.

[0016] Figure 6 This is a cross-sectional view showing in detail the structure of the laser cavity near the main electrode according to the second embodiment.

[0017] Figure 7 This is a diagram showing an example of the flow of laser gas in the second embodiment.

[0018] Figure 8 This is a cross-sectional view showing in detail the structure of the laser cavity near the main electrode according to the third embodiment.

[0019] Figure 9 This is a diagram showing an example of the flow of laser gas in the third embodiment.

[0020] Figure 10 This is a cross-sectional view showing in detail the structure of the laser cavity in the vicinity of the main electrode according to the fourth embodiment.

[0021] Figure 11 It is a diagram schematically showing a structural example of an exposure apparatus. DETAILED DESCRIPTION

[0022] <Content>

[0023] 1. Comparative Example

[0024] 1.1 Structure

[0025] 1.2 Action

[0026] 1.3 Topics

[0027] 2. First Implementation

[0028] 2.1 Structure

[0029] 2.2 Action

[0030] 2.3 Effect

[0031] 3. Second Implementation

[0032] 3.1 Structure

[0033] 3.2 Action

[0034] 3.3 Effect

[0035] 4. Third Implementation

[0036] 4.1 Structure

[0037] 4.2 Action

[0038] 4.3 Effect

[0039] 5. Fourth embodiment

[0040] 5.1 Structure

[0041] 5.2 Action

[0042] 5.3 Effect

[0043] 6. Method for manufacturing electronic devices

[0044] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and actions described in the embodiments may not all be required as the structures and actions of the present disclosure. In addition, the same reference numerals are given to the same components, and repeated descriptions are omitted.

[0045] 1. Comparative Example

[0046] First, comparative examples of the present disclosure will be described. The comparative examples of the present disclosure are methods that the applicant recognizes as being known only to the applicant and are not publicly known examples that the applicant recognizes.

[0047] 1.1 Structure

[0048] use Figure 1 as well as Figure 2 The structure of a gas laser device 2 according to a comparative example will be described. Figure 1 The structure of the gas laser device 2 is schematically shown. Figure 2 Observed from the Z direction Figure 1 1 is a cross-sectional view of a gas laser device 2. The gas laser device 2 is a discharge-excitation type gas laser device that performs discharge excitation on laser gas, and is, for example, an excimer laser device.

[0049] exist Figure 1 In the figure, the direction of travel of the pulsed laser light PL output from the gas laser device 2 is defined as the Z direction. The discharge direction, described later, is defined as the Y direction. Furthermore, the direction perpendicular to the Z and Y directions is defined as the X direction. Furthermore, the pulsed laser light PL is an example of "laser" in the technology disclosed herein. The Z direction is an example of the "first direction" in the technology disclosed herein. The Y direction is an example of the "second direction" in the technology disclosed herein. The X direction is an example of the "third direction" in the technology disclosed herein.

[0050] exist Figure 1 In FIG, the gas laser device 2 includes a laser chamber 10, a charger 11, a pulse power module (PPM) 12, a pulse energy measurement unit 13, a processor 14, a pressure sensor 17, and a laser resonator. The laser resonator is composed of a narrowband module 15 and an output coupling mirror 16.

[0051] The laser chamber 10 includes, for example, a container 10a formed of aluminum metal with nickel plating applied to the surface. Figure 1 and Figure 2 As shown, a main electrode 20, a ground plate 21, wiring 22, a fan 23, a heat exchanger 24, an insulating guide 28, a conductive guide 29, and a preionization electrode 30 are provided inside the container 10a. The preionization electrode 30 includes a preionization outer electrode 31, a dielectric tube 32, and a preionization inner electrode 33.

[0052] Fluorine-containing laser gas is enclosed in container 10a as a laser medium. The laser gas includes, for example, rare gases such as argon, krypton, and xenon, buffer gases such as neon and helium, and halogen gases such as fluorine and chlorine.

[0053] The container 10a has an opening. An electrical insulating plate 26 with a feedthrough 25 embedded therein is attached to the container 10a via an O-ring (not shown) to close the opening. The PPM 12 is placed on the electrical insulating plate 26. The container 10a is grounded.

[0054] PPM 12 includes a charging capacitor (not shown) connected to main electrode 20 via feedthrough 25. PPM 12 includes switch SW for discharging main electrode 20. Charger 11 is connected to the charging capacitor of PPM 12. Hereinafter, discharge generated at main electrode 20 is referred to as main discharge.

[0055] The main electrode 20 is composed of a cathode electrode 20a and an anode electrode 20b. The cathode electrode 20a and the anode electrode 20b are arranged within the container 10a so that their discharge surfaces face each other. The space between the discharge surfaces of the cathode electrode 20a and the anode electrode 20b is referred to as the discharge space 27. The cathode electrode 20a and the anode electrode 20b each extend in the Z direction.

[0056] The surface of cathode electrode 20a opposite the discharge surface is supported by an electrically insulating plate 26 and connected to feedthrough 25. Specifically, cathode electrode 20a is positioned relative to anode electrode 20b, facing anode electrode 20b, and closer to inner wall 10b of container 10a. The surface of anode electrode 20b opposite the discharge surface is supported by ground plate 21. Anode electrode 20b is an example of a "first electrode" in the disclosed technology. Cathode electrode 20a is an example of a "second electrode" in the disclosed technology.

[0057] The ground plate 21 is connected to the container 10a via the wiring 22. The container 10a is grounded. Therefore, the ground plate 21 is grounded via the wiring 22. The end portion of the ground plate 21 in the Z direction is fixed to the container 10a.

[0058] The fan 23 is a cross-flow fan for circulating the laser gas in the container 10a, and is arranged on the opposite side of the discharge space 27 from the ground plate 21. A motor 23a for rotationally driving the fan 23 is connected to the container 10a.

[0059] Laser gas blown from fan 23 flows into discharge space 27. The flow direction of the laser gas flowing into discharge space 27 is approximately parallel to the X direction. The laser gas flowing out of discharge space 27 is drawn into fan 23 via heat exchanger 24. Heat exchanger 24 changes the temperature of the laser gas by exchanging heat between the refrigerant supplied to the interior of heat exchanger 24 and the laser gas.

[0060] Insulating guide 28 is disposed on the discharge space 27 side of electrical insulating plate 26, sandwiching cathode electrode 20a. Insulating guide 28 is shaped to guide the flow of laser gas, allowing the laser gas from fan 23 to flow efficiently between cathode electrode 20a and anode electrode 20b. Insulating guide 28 and electrical insulating plate 26 are formed, for example, from a ceramic such as alumina (Al2O3), which has low reactivity with fluorine gas.

[0061] Conductive guide 29 is disposed on the discharge space 27 side of ground plate 21, sandwiching anode electrode 20b. Like insulating guide 28, conductive guide 29 is formed to guide the flow of laser gas, ensuring efficient flow of laser gas from fan 23 between cathode electrode 20a and anode electrode 20b. Conductive guide 29 is made of, for example, porous nickel metal, which has low reactivity with fluorine gas.

[0062] Laser chamber 10 is connected to a laser gas supply device 18a and a laser gas exhaust device 18b. Laser gas supply device 18a includes a valve and a flow control valve and is connected to a gas cylinder containing laser gas. Laser gas exhaust device 18b includes a valve and an exhaust pump.

[0063] Windows 19a and 19b are provided at the ends of the container 10a for emitting light generated in the container 10a to the outside. The laser chamber 10 is arranged so that the optical path of the optical resonator passes through the discharge space 27 and the windows 19a and 19b.

[0064] The bandwidth narrowing module 15 includes a prism 15a and a grating 15b. The prism 15a widens the beam width of light emitted from the laser chamber 10 through the window 19a and transmits the light toward the grating 15b.

[0065] Grating 15b is arranged in a Littrow configuration, where the incident angle and diffraction angle are equal. Grating 15b is a wavelength-selective element that selectively extracts light near a specific wavelength based on the diffraction angle. The spectral width of the light returning from grating 15b to laser chamber 10 via prism 15a is narrowed.

[0066] The output coupling mirror 16 transmits a portion of the light emitted from the laser chamber 10 through the window 19b and reflects the other portion to return it to the laser chamber 10. The surface of the output coupling mirror 16 is coated with a partial reflection film.

[0067] Light emitted from the laser chamber 10 reciprocates between the band-narrowing module 15 and the output coupling mirror 16, being amplified each time it passes through the discharge space 27. A portion of the amplified light is output as pulsed laser light PL via the output coupling mirror 16. The wavelength of the pulsed laser light PL is in the ultraviolet region of 150 nm to 380 nm, which is the oscillation wavelength of an excimer laser device, for example.

[0068] The pulse energy measurement unit 13 is arranged on the optical path of the pulse laser light PL outputted via the output coupling mirror 16. The pulse energy measurement unit 13 includes a beam splitter 13a, a focusing optical system 13b, and a light sensor 13c.

[0069] Beam splitter 13a transmits pulsed laser light PL with high transmittance and reflects a portion of the pulsed laser light PL toward focusing optical system 13b. Focusing optical system 13b focuses the light reflected by beam splitter 13a onto the light-receiving surface of optical sensor 13c. Optical sensor 13c measures the pulse energy of the light focused on the light-receiving surface and outputs the measured value to processor 14.

[0070] Pressure sensor 17 detects the gas pressure in container 10a and outputs the detected value to processor 14. Processor 14 determines the gas pressure of the laser gas in container 10a based on the detected gas pressure value and the charging voltage of charger 11.

[0071] The charger 11 is a high-voltage power source that supplies charging voltage to the charging capacitor included in the PPM 12. The switch SW of the PPM 12 is controlled by the processor 14. When the switch SW is turned from off to on, the PPM 12 generates a high-voltage pulse based on the electrical energy stored in the charging capacitor and applies it to the main electrode 20.

[0072] The processor 14 is a processing device that transmits and receives various signals to and from the exposure device controller 110 provided in the exposure device 100. For example, the target pulse energy of the pulsed laser PL to be output to the exposure device 100, an oscillation trigger signal, etc. are transmitted from the exposure device controller 110 to the processor 14.

[0073] The processor 14 centrally controls the operation of each component of the gas laser device 2 based on various signals sent from the exposure device controller 110 , the measured value of pulse energy, the detected value of gas pressure, and the like.

[0074] The processor 14 functions as a controller for the gas laser device 2. For example, the processor 14 is a processing device including a storage device storing a control program and a CPU (Central Processing Unit) that executes the control program. The processor 14 is specifically configured or programmed to perform the various processes included in the present disclosure. The storage device is a non-transitory computer-readable storage medium, and includes, for example, a memory serving as a primary storage device and a memory serving as an auxiliary storage device. Alternatively, the storage device may be a semiconductor memory, a hard disk drive (HDD), a solid-state drive (SSD), or a combination thereof.

[0075] The gas laser device 2 is not necessarily limited to a narrowband laser device, and may be a laser device that outputs natural oscillation light. For example, a high-reflection mirror may be provided instead of the narrowband module 15.

[0076] Figure 3 The structure near main electrode 20 of laser chamber 10 is shown in detail. In the following description, upstream refers to the side where laser gas flows into discharge space 27 with respect to discharge space 27. Downstream refers to the side where laser gas flows out of discharge space 27 with respect to discharge space 27.

[0077] The preionization outer electrode 31 is positioned between the anode electrode 20b and the dielectric tube 32, and is held in contact with the side surface of a metal holding member 34. The holding member 34 is fixed to the upstream side surface of the anode electrode 20b. The preionization inner electrode 33 is positioned within the dielectric tube 32, and the exterior of the dielectric tube 32 is in contact with the preionization outer electrode 31.

[0078] The insulating guide 28 is arranged to cover the upstream and downstream side surfaces of the cathode electrode 20a. The surface of the insulating guide 28 is inclined so as to get closer to the electrical insulating plate 26 as it gets farther away from the cathode electrode 20a.

[0079] The conductive guide 29 includes a first guide member 29a, a second guide member 29b, and a third guide member 29c. The first guide member 29a and the third guide member 29c are arranged upstream of the anode electrode 20b, while the second guide member 29b is arranged downstream of the anode electrode 20b.

[0080] First guide member 29a is disposed on ground plate 21 to guide laser gas into discharge space 27. Dielectric tube 32 is disposed between first guide member 29a and anode electrode 20b, spaced from ground plate 21 and anode electrode 20b. Second guide member 29b is disposed on ground plate 21 downstream of anode electrode 20b, covering the downstream side of anode electrode 20b.

[0081] The third guide member 29c is disposed between the dielectric tube 32 and the anode electrode 20b so as to cover the upstream side surface of the anode electrode 20b and guide the laser gas into the discharge space 27. The third guide member 29c is close to the dielectric tube 32.

[0082] The entire surface of the conductive guide 29 is inclined so as to get closer to the ground plate 21 as it becomes farther away from the anode electrode 20 b .

[0083] In this way, the insulating guide 28 and the conductive guide 29 form a laser gas flow path. To maximize the flow velocity of the laser gas flowing in the discharge space 27 and to prevent the acoustic waves generated by the main discharge from being reflected and returning to the discharge space 27, the width of the flow path in the Y direction increases as the distance from the discharge space 27 increases. Furthermore, to prevent the acoustic waves generated by the main discharge from being reflected by the inner wall 10b within the container 10a and returning to the discharge space 27, the portion of the inner wall 10b facing the discharge space 27 in the X direction is tilted relative to the Y direction, which is the discharge direction. Furthermore, acoustic waves are waves of density and sparseness in the laser gas.

[0084] The upstream and downstream side surfaces of cathode electrode 20a near the discharge surface are not covered by insulating guide 28 and protrude from the surface of insulating guide 28 toward anode electrode 20b.

[0085] The upstream and downstream side surfaces near the discharge surface of the anode electrode 20b are not covered by the conductive guide 29 and protrude from the surface of the conductive guide 29 toward the cathode electrode 20a.

[0086] 1.2 Action

[0087] Next, the operation of the gas laser device 2 of the comparative example will be described. First, the processor 14 controls the laser gas supply device 18a so as to supply laser gas into the container 10a of the laser chamber 10, and drives the motor 23a to rotate the fan 23. Figure 2 As shown by the middle arrow, the laser gas filled in the container 10a circulates.

[0088] The processor 14 receives the target pulse energy and the oscillation trigger signal transmitted from the exposure device controller 110. The oscillation trigger signal is a signal instructing the gas laser device 2 to output the pulsed laser light PL for one pulse.

[0089] The processor 14 sets a charging voltage corresponding to the target pulse energy in the charger 11. The processor 14 operates the switch SW of the PPM 12 in synchronization with the oscillation trigger signal.

[0090] When the switch SW of PPM 12 is turned from off to on, a voltage is applied between the preionization inner electrode 33 and the preionization outer electrode 31 of the preionization electrode 30, and between the cathode electrode 20a and the anode electrode 20b. This generates a corona discharge in the preionization electrode 30, generating UV (ultraviolet) light. The UV light irradiates the laser gas in the discharge space 27, preionizing the laser gas.

[0091] Then, when the voltage between cathode electrode 20a and anode electrode 20b reaches the dielectric breakdown voltage, a main discharge occurs in discharge space 27. If the discharge direction of the main discharge is defined as the direction of electron flow, the discharge direction is from cathode electrode 20a toward anode electrode 20b. When the main discharge occurs, the laser gas in discharge space 27 is excited, causing light to be emitted.

[0092] The light emitted from the laser gas is reflected by the band-narrowing module 15 and the output coupling mirror 16 and reciprocates within the laser resonator, thereby performing laser oscillation. The light narrowed by the band-narrowing module 15 is output from the output coupling mirror 16 as pulsed laser light PL.

[0093] A portion of the pulse laser light PL output from the output coupling mirror 16 enters the pulse energy measuring unit 13 . The pulse energy measuring unit 13 measures the pulse energy of the incident pulse laser light PL and outputs the measured value to the processor 14 .

[0094] The processor 14 calculates the difference ΔE between the measured pulse energy and the target pulse energy. The processor 14 performs feedback control on the charging voltage based on the difference ΔE so that the measured pulse energy reaches the target pulse energy.

[0095] When the charge voltage exceeds the maximum allowable value, processor 14 controls laser gas supply device 18a to supply laser gas into container 10a until the pressure reaches a predetermined value. Alternatively, when the charge voltage falls below the minimum allowable value, processor 14 controls laser gas exhaust device 18b to exhaust laser gas from container 10a until the pressure reaches a predetermined value.

[0096] The pulse laser light PL transmitted through the pulse energy measurement unit 13 enters the exposure device 100 .

[0097] 1.3 Topics

[0098] exist Figure 3Figure 2 shows the flow of laser gas circulating within container 10a. Laser gas, having passed through discharge space 27 from the upstream side, changes direction in the downstream space before flowing toward heat exchanger 24. This downstream space contains a region of stagnation. In this region, a portion of the laser gas flow generates an eddy current. This eddy current compresses the laser gas flow path, creating a source of resistance to the laser gas flow. As a result, the flow rate of the laser gas flowing through discharge space 27 decreases, and discharge products generated by the main discharge remain in discharge space 27, making the main discharge unstable. This deteriorates the energy stability of the pulsed laser light PL.

[0099] Therefore, an object of the present invention is to provide a laser chamber, a gas laser apparatus, and a method for manufacturing an electronic device, which are capable of increasing the flow rate of laser gas flowing through discharge space 27 .

[0100] 2. First Implementation

[0101] 2.1 Structure

[0102] The gas laser device 2 according to the first embodiment of the present disclosure has the same structure as the gas laser device 2 according to the comparative example, except that the structure of the laser chamber 10 is different.

[0103] Figure 4 The structure near the main electrode 20 of the laser chamber 10 according to the first embodiment is shown in detail. In this embodiment, a vortex divider 40 is provided within the container 10a to divide the vortex flow. In this embodiment, the vortex divider 40 is composed of a plurality of structures 50. These structures 50 are discretely arranged along the laser gas flow, downstream of the insulating guide 28 positioned downstream of the cathode electrode 20a. The structures 50 are arranged with gaps between them. Figure 4 The case where the vortex dividing member 40 includes two structures 50 is shown.

[0104] The structure 50 has an L-shaped cross-section in the XY plane perpendicular to the Z direction. The structure 50 is a so-called bracket. The structure 50 extends in the Z direction while maintaining a consistent cross-sectional shape. Its two ends in the Z direction are fixed to the inner wall 10b of the container 10a. In addition to having its ends fixed to the inner wall 10b, the structure 50 may also be supported by supports (not shown) connected to the inner wall 10b.

[0105] The structure 50 is preferably formed of, for example, aluminum plated with electroless nickel, alumina ceramics, nickel, or the like.

[0106] The structure 50 has two linear portions 51 that intersect each other orthogonally in the XY plane. The two linear portions 51 are of equal length and connected at their ends. To prevent reflected sound waves from returning to the discharge space 27, the structure 50 is arranged so that the two linear portions 51 are tilted relative to the Y direction, which is the discharge direction.

[0107] In order to divide the eddy current and suppress the acoustic waves returning to the discharge space 27 , the sizes and arrangements of the plurality of structures 50 are preferably determined so as to satisfy the following conditions.

[0108] First, in the XY plane, the point where the inner wall 10b and the insulating guide 28 are in contact on the downstream side of the cathode electrode 20a is set as the first point P1, and the point where the inner wall 10b becomes parallel to the discharge direction is set as the second point P2. In this disclosure, "contact" is not limited to contact, but also includes proximity. Figure 4 In the figure, the first point P1 is the point where the inner wall 10b and the electrical insulating plate 26 are connected in the XY plane. The second point P2 is the end of the inclined surface of the inner wall 10b that is inclined relative to the discharge direction. In addition, the distance between the first point P1 and the second point P2 in the Y direction is referred to as the first distance L. h , the distance between the first point P1 and the second point P2 in the X direction is set to the second distance L w .

[0109] When the number of structures 50 included in the eddy flow dividing member 40 is N and the length of each of the two straight portions 51 is S, it is preferable that the following equations (1) and (2) are satisfied.

[0110] S≤L h / (2N)···(1)

[0111] S≤L w / (2N)···(2)

[0112] The point connecting the two straight portions 51 is defined as the vertex A of the structure 50. The distance in the Y direction between the vertex A of the structure 50 closest to the first point P1 among the plurality of structures 50 and the inner wall 10b is defined as L. a1h In the case of , it is preferable to satisfy the following formula (3).

[0113] 0 <L a1h ≤L h / (2N)···(3)

[0114] In addition, the distance in the X direction between the vertex A of the structure 50 closest to the second point P2 among the plurality of structures 50 and the inner wall 10b is defined as L. a1w In the case of , it is preferable to satisfy the following formula (4).

[0115] 0 <L a1w ≤Lw / (2N)···(4)

[0116] Furthermore, the above formulas (3) and (4) include a range in which the orientation of the structure 50 in the XY plane is restricted in order to avoid contact with the inner wall 10 b .

[0117] When the distance in the Y direction between the vertices A of two adjacent structures 50 is L a2h In the case of , it is preferable to satisfy the following formula (5).

[0118] L a2h ≤(L h -S / 2-L a1h ) / (N-1)···(5)

[0119] In addition, the distance in the X direction between the vertices A of two adjacent structures 50 is set to L. a2w In the case of , it is preferable to satisfy the following formula (6).

[0120] L a2w ≤(L w -S / 2-L a1w ) / (N-1)···(6)

[0121] Furthermore, two structures 50 adjacent to each other refer to a combination of one structure 50 and a structure 50 having a vertex A closest to the vertex A of the structure 50 .

[0122] 2.2 Action

[0123] The operation of the gas laser device 2 of this embodiment is the same as that of the comparative example, except for the fact that the vortex dividing member 40 is provided in the container 10 a .

[0124] Figure 5 An example of the flow of the laser gas in the first embodiment is shown. Figure 5 As shown, in this embodiment, similarly to the comparative example, stagnation occurs in the space downstream from the discharge space 27 , and an eddy current is generated in the region where the stagnation occurs. However, the eddy current is divided into a plurality of small eddies by the eddy current dividing member 40 .

[0125] 2.3 Effect

[0126] In this embodiment, the eddy current is divided into multiple small eddies by the eddy current divider 40, thereby reducing the flow resistance of the laser gas caused by the eddy current. As a result, the flow rate of the laser gas flowing through the discharge space 27 is increased, and the discharge products remaining in the discharge space 27 are reduced. This improves the stability of the main discharge and the energy stability of the pulsed laser PL. Furthermore, the present applicant conducted simulations using "SOLIDWORKS 2019 Flow Simulation," a thermal fluid analysis software developed by SolidWorks, and confirmed that the flow rate in this embodiment is 2% higher than in the comparative example.

[0127] Furthermore, vortex divider 40 is composed of a plurality of structures 50 discretely arranged along the flow of laser gas. This reduces the area over which sound waves are reflected by vortex divider 40 and thereby suppresses sound waves reflected by vortex divider 40 and returning to discharge space 27. Furthermore, by arranging the two linear portions 51 so that each is inclined relative to the Y direction, which is the discharge direction, the return of sound waves to discharge space 27 can be further suppressed. By suppressing the return of sound waves to discharge space 27 in this manner, the energy stability of pulsed laser light PL is further improved.

[0128] 3. Second Implementation

[0129] 3.1 Structure

[0130] The gas laser device 2 according to the second embodiment of the present disclosure has the same structure as the gas laser device 2 according to the first embodiment, except for the structure of the laser chamber 10 .

[0131] Figure 6 The structure near the main electrode 20 of the laser chamber 10 according to the second embodiment is shown in detail. In this embodiment, as in the first embodiment, a vortex divider 40 for dividing the vortex is provided within the container 10a. In this embodiment, the vortex divider 40 is composed of a plurality of structures 60, which are discretely arranged along the flow of the laser gas, downstream of the insulating guide 28 disposed downstream of the cathode electrode 20a. Figure 6 The case where the vortex dividing member 40 includes two structures 60 is shown.

[0132] The structure 60 has the same structure as the structure 50 of the first embodiment, except for its different cross-sectional shape. The cross-sectional shape of the structure 60 in the XY plane, which is perpendicular to the Z direction, is circular. The structure 60 is a so-called cylindrical rod. In this embodiment, the structure 60 is a hollow cylinder with a circular hollow portion. Alternatively, the structure 60 may be a solid cylinder without a hollow portion.

[0133] The structure 60 extends in the Z direction while maintaining the same cross-sectional shape, and its ends in the Z direction are fixed to the inner wall 10b of the container 10a. In addition to being fixed to the inner wall 10b at both ends, the structure 60 may also be supported by pillars (not shown) connected to the inner wall 10b.

[0134] The structure 60 is preferably formed of, for example, aluminum plated with electroless nickel, alumina ceramics, nickel, or the like.

[0135] In order to divide the eddy current and suppress the acoustic waves returning to the discharge space 27, the sizes and arrangements of the plurality of structures 60 are preferably determined to satisfy the following conditions. h and the second distance L w The definition of is the same as that of the first embodiment.

[0136] When the number of structures 60 included in the eddy flow dividing member 40 is N and the outer diameter of the structure 60 is D, it is preferable that the following equations (7) and (8) are satisfied.

[0137] D≤L h / (2N)···(7)

[0138] D≤L w / (2N)···(8)

[0139] The distance in the Y direction between the center C of the structure 60 closest to the first point P1 among the plurality of structures 60 and the inner wall 10b is defined as L. c1h In the case of , it is preferable to satisfy the following formula (9).

[0140] 0 <L c1h ≤L h / (2N)···(9)

[0141] In addition, the distance in the X direction between the center C of the structure 60 closest to the second point P2 among the plurality of structures 60 and the inner wall 10b is defined as L. c1w In the case of , it is preferable to satisfy the following formula (10).

[0142] 0 <L c1w ≤L w / (2N)···(10)

[0143] When the distance in the Y direction between the centers C of two adjacent structures 60 is L c2h In the case of , it is preferable to satisfy the following formula (11).

[0144] L c2h ≤(L h -D / 2-L c1h ) / (N-1)···(11)

[0145] In addition, the distance in the X direction between the centers C of two adjacent structures 60 is set to L. c2w In the case of , it is preferable to satisfy the following formula (12).

[0146] L c2w ≤(L w -D / 2-L c1w ) / (N-1)···(12)

[0147] Furthermore, two structures 60 adjacent to each other refer to a combination of one structure 60 and a structure 60 having a center C closest to the center C of the structure 60 .

[0148] 3.2 Action

[0149] The operation of the gas laser device 2 of this embodiment is the same as that of the comparative example, except for the fact that the vortex dividing member 40 is provided in the container 10 a .

[0150] Figure 7 An example of the flow of the laser gas in the second embodiment is shown. Figure 7 As shown, in this embodiment, similar to the first embodiment, the vortex is divided into a plurality of small vortices by the vortex dividing member 40 .

[0151] 3.3 Effect

[0152] In this embodiment, as in the first embodiment, the vortex is divided into multiple small vortices by the vortex dividing member 40, thereby improving the energy stability of the pulsed laser PL. In addition, simulations confirmed that the flow velocity in this embodiment is increased by 1% compared to the comparative example.

[0153] Furthermore, in this embodiment as well, since vortex divider 40 is composed of a plurality of structures 60 discretely arranged along the flow of laser gas, and the area over which acoustic waves are reflected is small, it is possible to suppress acoustic waves reflected by vortex divider 40 and returning to discharge space 27. Furthermore, in this embodiment, the cross-sectional shape of structures 60 is circular, further suppressing acoustic waves returning to discharge space 27. By suppressing acoustic waves returning to discharge space 27 in this manner, the energy stability of pulsed laser light PL is further improved.

[0154] 4. Third Implementation

[0155] 4.1 Structure

[0156] The gas laser device 2 according to the third embodiment of the present disclosure has the same structure as the gas laser device 2 according to the first embodiment, except that the structure of the laser chamber 10 is different.

[0157] Figure 8 The structure of the laser chamber 10 near the main electrode 20 of the third embodiment is shown in detail. In this embodiment, as in the first embodiment, a vortex divider 40 for dividing the vortex is provided within the container 10a. In this embodiment, the vortex divider 40 is a mesh plate 70, which is positioned downstream of the insulating guide 28 positioned downstream of the cathode electrode 20a, along the flow of the laser gas.

[0158] The mesh plate 70 extends in the Z direction, maintaining a uniform cross-sectional shape. Its two ends in the Z direction are fixed to the inner wall 10b of the container 10a. Furthermore, both ends of the mesh plate 70 in the XY plane are in contact with the inner wall 10b. In addition to being fixed to the inner wall 10b at both ends, the mesh plate 70 may also be supported by supports (not shown) connected to the inner wall 10b.

[0159] The mesh plate 70 is a mesh-like member having a plurality of two-dimensional openings 71. That is, the mesh plate 70 is composed of a plurality of structures discretely arranged along the flow of the laser gas.

[0160] The mesh plate 70 is preferably formed of, for example, aluminum plated with electroless nickel, alumina ceramic, nickel, or the like.

[0161] In order to divide the eddy current and suppress the sound waves returning to the discharge space 27, the mesh plate 70 is preferably configured to meet the following conditions. In addition, the first point P1, the second point P2, the first distance L h and the second distance L w The definition of is the same as that of the first embodiment.

[0162] In the XY plane, the point closer to the first point P1 of the two points where the mesh 70 contacts the inner wall 10b is defined as the third point P3, and the point closer to the second point P2 is defined as the fourth point P4. mh In the case of , it is preferred to satisfy the following formula (13).

[0163] 0.25L h ≤L mh ≤L h ···(13)

[0164] In addition, the distance between the third point P3 and the fourth point P4 in the X direction is set to L mw In the case of , it is preferred to satisfy the following formula (14).

[0165] 0.25L w ≤L mw ≤L w ···(14)

[0166] In this manner, the mesh plate 70 is preferably disposed in a space defined by the straight line K connecting the first point P1 and the second point P2 and the inner wall 10 b.

[0167] In the present embodiment, the mesh plate 70 is arranged in a straight line connecting the third point P3 and the fourth point P4 on the XY plane, but may be arranged in a curved line connecting the third point P3 and the fourth point P4.

[0168] In order to suppress the acoustic waves returning to the discharge space 27, the mesh 70 preferably has two or more openings 71 per 1 inch square. The mesh 70 preferably has an opening ratio of 50% to 80%.

[0169] 4.2 Action

[0170] The operation of the gas laser device 2 of this embodiment is the same as that of the comparative example, except for the fact that the vortex dividing member 40 is provided in the container 10 a .

[0171] Figure 9 An example of the flow of the laser gas in the third embodiment is shown. Figure 9 As shown, in this embodiment, similar to the first embodiment, the vortex is divided into a plurality of small vortices by the vortex dividing member 40 .

[0172] 4.3 Effect

[0173] In this embodiment, as in the first embodiment, the vortex is divided into multiple small vortices by the vortex dividing member 40, thereby improving the energy stability of the pulsed laser PL. In addition, simulations confirmed that the flow velocity in this embodiment is increased by 1% compared to the comparative example.

[0174] Furthermore, in this embodiment, the vortex divider 40 is a mesh plate 70 composed of a plurality of structures discretely arranged along the flow of the laser gas. This reduces the area over which sound waves are reflected by the vortex divider 40 and thus suppresses sound waves that are reflected by the vortex divider 40 and return to the discharge space 27. By suppressing the sound waves that return to the discharge space 27 in this manner, the energy stability of the pulsed laser PL is further improved.

[0175] 5. Fourth embodiment

[0176] 5.1 Structure

[0177] The gas laser device 2 according to the fourth embodiment of the present disclosure has the same structure as the gas laser device 2 according to the first embodiment, except that the structure of the laser chamber 10 is different.

[0178] Figure 10The structure of the laser chamber 10 near the main electrode 20 of the fourth embodiment is shown in detail. In this embodiment, as in the first embodiment, a vortex divider 40 for dividing the vortex is provided within the container 10a. In this embodiment, the vortex divider 40 is formed by combining a plurality of structures 60 and a mesh plate 70.

[0179] The structure 60 has the same structure as the structure 60 described in the second embodiment. The mesh 70 has the same structure as the mesh 70 described in the third embodiment. The size and arrangement of the multiple structures 60 can be the same as in the second embodiment. The arrangement and aperture ratio of the mesh 70 can be the same as in the second embodiment.

[0180] The mesh plate 70 is arranged in a curved shape so as to avoid the plurality of structures 60. In this embodiment, the plurality of structures 60 are arranged in a space surrounded by the mesh plate 70 and the inner wall 10b, and the plurality of structures 60 are in contact with the mesh plate 70.

[0181] 5.2 Action

[0182] The operation of the gas laser device 2 of this embodiment is the same as that of the comparative example, except for the fact that the vortex dividing member 40 is provided in the container 10 a .

[0183] Figure 10 FIG. 4 shows an example of the flow of the laser gas in the fourth embodiment. Figure 10 As shown, in this embodiment, compared with the second and third embodiments, the vortex dividing member 40 can divide the vortex into a plurality of smaller vortexes.

[0184] 5.3 Effect

[0185] According to this embodiment, compared with the second and third embodiments, the eddy current can be divided into multiple smaller eddies, thereby further reducing the flow path resistance and further increasing the flow velocity of the laser gas flowing in the discharge space 27. This further improves the energy stability of the pulsed laser PL.

[0186] In addition, the eddy flow dividing member 40 may be configured by combining a plurality of structures 50 and mesh plates 70. The structure 50 has the same structure as the structure 50 described in the first embodiment.

[0187] 6. Method for manufacturing electronic devices

[0188] Figure 11An example configuration of an exposure apparatus 100 is schematically shown. Exposure apparatus 100 includes an illumination system 104 and a projection system 106. Illumination system 104 illuminates the reticle pattern of a mask (not shown) placed on reticle stage RT using pulsed laser light PL incident from, for example, a gas laser device 2. Projection system 106 projects the pulsed laser light PL transmitted through the reticle into a reduced image onto a workpiece (not shown) placed on workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0189] Exposure apparatus 100 synchronizes and parallels the reticle stage RT and workpiece stage WT to expose a workpiece with pulsed laser light PL reflecting the reticle pattern. After the reticle pattern is transferred to a semiconductor wafer through the aforementioned exposure steps, semiconductor devices can be manufactured through multiple steps. Semiconductor devices are an example of "electronic devices" in this disclosure.

[0190] Furthermore, the gas laser device 2 is not limited to the manufacture of electronic devices, but can also be used for laser processing such as hole drilling.

[0191] The above description is for illustrative purposes only and is not intended to be limiting. Therefore, it will be apparent to those skilled in the art that modifications may be made to the various embodiments of the present disclosure without departing from the scope of the appended claims.

[0192] The terms used in this specification and the appended claims should be interpreted as "non-restrictive" terms. For example, the terms "include" or "comprise" should be interpreted as "not limited to the parts described as including". The term "have" should be interpreted as "not limited to the parts described as having". In addition, the phrases "one" and "one" described in this specification and the appended claims should be interpreted as "at least one" or "one or more". In addition, the term "at least one of A, B and C" should be interpreted as "A", "B", "C", "A+B", "A+C", "B+C" or "A+B+C", and should be interpreted as also including combinations thereof with parts other than "A", "B" and "C".

Claims

1. A laser chamber, which is a laser chamber of a gas laser device that outputs laser light, comprising: a container filled with laser gas; a first electrode extending along a first direction and disposed in the container; a second electrode extending along the first direction so as to oppose the first electrode in a second direction perpendicular to the first direction and arranged closer to the inner wall of the container than the first electrode; a fan configured to flow the laser gas in a discharge space between the first electrode and the second electrode; an insulating guide member disposed on a downstream side of the second electrode; as well as The vortex dividing component is composed of a plurality of structures, which divides the vortex generated by a portion of the laser gas flow. The plurality of structures extend along the first direction and are discretely arranged along the direction of the laser gas flow at a position downstream of the insulating guide.

2. The laser chamber according to claim 1, wherein: The structure is a bracket composed of two linear portions whose cross sections on a plane perpendicular to the first direction are perpendicular to each other.

3. The laser chamber according to claim 2, wherein: In a plane perpendicular to the first direction, a point where the inner wall on the downstream side of the second electrode contacts the insulating guide is defined as a first point, a point where the slope of the inner wall becomes parallel to the second direction is defined as a second point, and a direction perpendicular to the first and second directions is defined as a third direction. The distance between the first point and the second point in the second direction is set to L h , the distance between the first point and the second point in the third direction is set to L w , when the number of the structures constituting the eddy flow dividing member is N and the length of each of the two straight portions is S, S≤L h / (2N) and S≤L w / (2N).

4. The laser chamber according to claim 3, wherein: The distance between the vertex of the structure closest to the first point among the plurality of structures and the inner wall in the second direction is set to L a1h In the case of <h2 style=";text-align:left;direction:ltr">0<L<h2 style=";text-align:left;direction:ltr"> a1h <h2 style=";text-align:left;direction:ltr"> ≤L<h2 style=";text-align:left;direction:ltr"> h <h2 style=";text-align:left;direction:ltr"> / (2N)。 5. The laser chamber according to claim 4, wherein: The distance between the vertex of the structure closest to the first point among the plurality of structures and the inner wall in the third direction is set to L a1w In the case of <h2 style=";text-align:left;direction:ltr">0<L<h2 style=";text-align:left;direction:ltr"> a1w <h2 style=";text-align:left;direction:ltr"> ≤L<h2 style=";text-align:left;direction:ltr"> w <h2 style=";text-align:left;direction:ltr"> / (2N)。 6. The laser chamber according to claim 5, wherein: The distance in the second direction between the vertices of the two adjacent structures is set to L a2h In the case of L a2h ≤(L h -S / 2-L a1h ) / (N-1)。 7. The laser chamber according to claim 6, wherein: The distance in the third direction between the vertices of the two adjacent structures is set to L. a2w In the case of L a2w ≤(L w -S / 2-L a1w ) / (N-1)。 8. The laser chamber according to claim 1, wherein: The structure is a cylinder whose cross-section on a plane perpendicular to the first direction is circular.

9. The laser chamber according to claim 8, wherein: In a plane perpendicular to the first direction, a point where the inner wall on the downstream side of the second electrode contacts the insulating guide is defined as a first point, a point where the slope of the inner wall becomes parallel to the second direction is defined as a second point, and a direction perpendicular to the first and second directions is defined as a third direction. The distance between the first point and the second point in the second direction is set to L h , the distance between the first point and the second point in the third direction is set to L w , when the number of the structures constituting the eddy flow dividing member is N and the outer diameter of the structure is D, D≤L h / (2N) and D≤L w / (2N).

10. The laser chamber according to claim 9, wherein: The distance between the center of the structure closest to the first point among the plurality of structures and the inner wall in the second direction is set to L c1h In the case of <h2 style=";text-align:left;direction:ltr">0<L<h2 style=";text-align:left;direction:ltr"> c1h <h2 style=";text-align:left;direction:ltr"> ≤L<h2 style=";text-align:left;direction:ltr"> h <h2 style=";text-align:left;direction:ltr"> / (2N)。 11. The laser chamber according to claim 10, wherein: The distance between the center of the structure closest to the first point among the plurality of structures and the inner wall in the third direction is set to L c1w In the case of <h2 style=";text-align:left;direction:ltr">0<L<h2 style=";text-align:left;direction:ltr"> c1w <h2 style=";text-align:left;direction:ltr"> ≤L<h2 style=";text-align:left;direction:ltr"> w <h2 style=";text-align:left;direction:ltr"> / (2N)。 12. The laser chamber according to claim 11, wherein: The distance in the second direction between the centers of the two adjacent structures is set to L. c2h In the case of L c2h ≤(L h -S / 2-L c1h ) / (N-1)。 13. The laser chamber according to claim 12, wherein: The distance in the third direction between the centers of the two adjacent structures is set to L. c2w In the case of L c2w ≤(L w -S / 2-L c1w ) / (N-1)。 14. The laser chamber according to claim 8, wherein: The structure is a hollow cylinder with a hollow portion.

15. The laser chamber according to claim 1, wherein: The eddy current dividing component is a mesh plate.

16. The laser chamber according to claim 15, wherein: In a plane perpendicular to the first direction, with the point where the inner wall on the downstream side of the second electrode meets the insulating guide as the first point, and the point where the inclined surface of the inner wall becomes parallel to the second direction as the second point, the eddy current dividing component is arranged in a space defined by a straight line connecting the first point and the second point and the inner wall.

17. The laser chamber of claim 1, wherein: The eddy flow dividing component is composed of a combination of a mesh plate and a plurality of cylinders, and the cross-section of the plurality of cylinders on a plane perpendicular to the first direction has a circular shape.

18. The laser chamber of claim 1, wherein: The eddy flow dividing member is composed of a combination of a mesh plate and a plurality of brackets, and the plurality of brackets are composed of two linear portions whose cross sections on a plane perpendicular to the first direction are orthogonal to each other.

19. A gas laser device that outputs laser light and comprises: an optical resonator; and a laser cavity configured to pass an optical path of the optical resonator, The laser chamber comprises: a container filled with laser gas; a first electrode extending along a first direction and disposed in the container; a second electrode extending along the first direction so as to oppose the first electrode in a second direction perpendicular to the first direction and arranged closer to the inner wall of the container than the first electrode; a fan configured to flow the laser gas in a discharge space between the first electrode and the second electrode; an insulating guide member disposed on a downstream side of the second electrode; as well as The vortex dividing component is composed of a plurality of structures, which divides the vortex generated by a portion of the laser gas flow. The plurality of structures extend along the first direction and are discretely arranged along the direction of the laser gas flow at a position downstream of the insulating guide.

20. A method for manufacturing an electronic device, wherein: Laser is generated by a gas laser device, Outputting the laser to an exposure device, exposing the laser to a photosensitive substrate in the exposure device to manufacture an electronic device, The gas laser device outputs the laser and comprises: an optical resonator; and a laser cavity configured to pass an optical path of the optical resonator, The laser chamber comprises: a container filled with laser gas; a first electrode extending along a first direction and disposed in the container; a second electrode extending along the first direction so as to oppose the first electrode in a second direction perpendicular to the first direction and arranged closer to the inner wall of the container than the first electrode; a fan configured to flow the laser gas in a discharge space between the first electrode and the second electrode; an insulating guide member disposed on a downstream side of the second electrode; and The vortex dividing component is composed of a plurality of structures, which divides the vortex generated by a portion of the laser gas flow. The plurality of structures extend along the first direction and are discretely arranged along the direction of the laser gas flow at a position downstream of the insulating guide.

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