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

Abstract

A laser cavity device according to one aspect of the present disclosure is provided with a magnetic coupling mechanism that transmits a driving force to a rotating shaft of a fan that circulates a laser gas, the magnetic coupling mechanism including an inner rotor in which a first magnet is disposed, and an outer rotor in which a second magnet is disposed at a position facing the first magnet on the outside of the inner rotor. At least one of the first magnet and the second magnet is movable in the thrust direction of the bearing.

Description

Technical Field

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

[0002] In recent years, semiconductor exposure equipment has been required to 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, when a projection lens is constructed using a material that transmits ultraviolet light such as KrF and ArF laser light, 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 light output from the gas laser device to a level where chromatic aberration is invisible. Therefore, in order to narrow the spectral line width, the laser resonator of the gas laser device sometimes has a narrowing module (Line Narrowing Module: LNM) containing narrowing elements (etalon, grating, etc.). 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: Japanese Patent Application Laid-Open No. 2001-99194

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-43194 Summary of the Invention

[0008] A laser cavity device according to one aspect of the present disclosure includes: a laser cavity that contains laser gas; a fan disposed within the laser cavity to circulate the laser gas; a bearing that rotatably supports a rotating shaft of the fan; and a magnetic coupling mechanism that transmits a driving force of a motor to the rotating shaft of the fan using magnetic force, the magnetic coupling mechanism comprising:

[0009] An inner rotor is connected to the rotating shaft of the fan and is provided with a first magnet; and an outer rotor is connected to the driving shaft of the motor and is provided with a second magnet on the outside of the inner rotor at a position opposite to the first magnet. The outer rotor is rotated by the driving force of the motor and causes the inner rotor to rotate by magnetic attraction. At least one of the first magnet and the second magnet can be moved in the thrust direction of the bearing due to the magnetic attraction.

[0010] A gas laser device according to one aspect of the present disclosure includes: a laser cavity that accommodates a discharge electrode and laser gas; a fan that is arranged inside the laser cavity and circulates the laser gas; a bearing that rotatably supports the rotating shaft of the fan; a motor that drives the fan; and a magnetic coupling mechanism that uses magnetic force to transmit the driving force of the motor to the rotating shaft of the fan. The gas laser device generates laser light by exciting the laser gas by discharge. The magnetic coupling mechanism includes: an inner rotor that is connected to the rotating shaft of the fan and is provided with a first magnet; and an outer rotor that is connected to the driving shaft of the motor and is provided with a second magnet on the outside of the inner rotor at a position opposite to the first magnet. The outer rotor is rotated by the driving force of the motor and is driven to rotate the inner rotor by magnetic attraction. At least one of the first magnet and the second magnet can be moved in the thrust direction of the bearing by the magnetic attraction.

[0011] According to one aspect of the present disclosure, a method for manufacturing an electronic device includes the following steps: generating laser light using a gas laser device, outputting the laser light to an exposure device, and exposing a photosensitive substrate to the laser light within the exposure device to manufacture the electronic device. The gas laser device includes: a laser cavity that houses a discharge electrode and laser gas; a fan disposed within the laser cavity and circulates the laser gas; a bearing that rotatably supports a rotating shaft of the fan; a motor that drives the fan; and a magnetic coupling mechanism that transmits the motor's driving force to the fan's rotating shaft using magnetic force. The gas laser device generates laser light by exciting the laser gas through discharge. The magnetic coupling mechanism includes: an inner rotor coupled to the fan's rotating shaft and having a first magnet disposed thereon; and an outer rotor coupled to the motor's drive shaft, having a second magnet disposed outside the inner rotor at a position opposing the first magnet. The outer rotor rotates due to the motor's driving force and causes the inner rotor to rotate following the motor's attraction force. At least one of the first and second magnets can be moved in the thrust direction of the bearing due to the attraction force. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings, merely as examples.

[0013] Figure 1 It is a cross-sectional view schematically showing the structure of a gas laser device according to a comparative example.

[0014] Figure 2 It is a cross-sectional view schematically showing the structure of a magnetic coupling mechanism of a comparative example.

[0015] Figure 3 1 and 2 are cross-sectional views showing a cross section parallel to the axial direction and a cross-sectional view showing a cross section perpendicular to the axial direction of a magnetic coupling mechanism according to a comparative example.

[0016] Figure 4It is a diagram for explaining the problems of the magnetic coupling mechanism of the comparative example.

[0017] Figure 5 It is a cross-sectional view schematically showing the structure of the magnetic coupling mechanism according to the first embodiment.

[0018] Figure 6 It is a diagram for explaining the operation of the first embodiment.

[0019] Figure 7 It is a cross-sectional view showing Modification 1 of the first embodiment.

[0020] Figure 8 This is a diagram for explaining the operation of Modification Example 1.

[0021] Figure 9 It is a cross-sectional view showing a second modification of the first embodiment.

[0022] Figure 10 It is a cross-sectional view schematically showing the structure of the magnetic coupling mechanism according to the second embodiment.

[0023] Figure 11 It is a cross-sectional view schematically showing the structure of a magnetic coupling mechanism according to the third embodiment.

[0024] Figure 12 It is a diagram schematically showing a structural example of an exposure apparatus. DETAILED DESCRIPTION

[0025] <Content>

[0026] 1. Comparative Example

[0027] 1.1 Structure

[0028] 1.1.1 Structure of a gas laser device

[0029] 1.1.2 Structure of magnetic coupling mechanism and bearing

[0030] 1.1.2.1 Bearing structure

[0031] 1.1.2.2 Structure of magnetic coupling mechanism

[0032] 1.2 Action

[0033] 1.3 Topics

[0034] 2. First Implementation

[0035] 2.1 Structure

[0036] 2.2 Action and Effect

[0037] 2.3 Modification of the First Embodiment

[0038] 2.3.1 Modification 1

[0039] 2.3.2 Modification 2

[0040] 3. Second embodiment

[0041] 3.1 Structure

[0042] 3.2 Action and Effect

[0043] 4. Third Implementation

[0044] 5. Other variations

[0045] 6. Method for manufacturing electronic devices

[0046] 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 are not necessarily required as the structures and actions of the present disclosure. In addition, the same reference numerals are marked on the same components, and repeated descriptions are omitted.

[0047] 1. Comparative Example

[0048] First, comparative examples of the present disclosure will be described. The comparative examples of the present disclosure are methods that the applicant has recognized as being known only to the applicant and are not publicly known examples that the applicant has acknowledged.

[0049] 1.1 Structure

[0050] 1.1.1 Structure of a gas laser device

[0051] use Figure 1 The structure of a gas laser device 2 in a comparative example is schematically shown. The gas laser device 2 is a laser light source that generates pulsed laser light PL. The pulsed laser light PL generated by the gas laser device 2 is supplied to, for example, an exposure device 3. The gas laser device 2 is a discharge-excited gas laser device that excites laser gas through discharge, and is, for example, an excimer laser device. Among laser gases, noble gases such as krypton and xenon can be used in addition to argon, and halogen gases such as chlorine can be used in addition to fluorine. Buffer gases such as neon and helium, or mixtures thereof, can be used.

[0052] exist Figure 1 In FIG. 1 , the traveling direction of the pulse laser light PL output from the gas laser device 2 is defined as the Z direction. The X direction and the Y direction are perpendicular to each other, and the XY plane is perpendicular to the Z direction.

[0053] The gas laser device 2 includes a housing 9 , a laser cavity 10 , a charger 11 , a pulse power module (PPM) 12 , a pulse energy measurement unit 13 , a laser control unit 14 , a pressure sensor 17 , and a laser resonator.

[0054] Housing 9 houses the various components of gas laser device 2. Housing 9 is provided with an air intake port 9A and an air exhaust port 9B. Air intake port 9A and air exhaust port 9B serve as ventilation ports for ventilation within housing 9 and for introducing cooling gas from the outside into housing 9. Housing 9 is also provided with an emission window 9C for emitting pulsed laser light PL toward exposure device 3.

[0055] The laser cavity 10 is a metal container formed of aluminum metal with nickel plating on the surface, for example, and laser gas is sealed in the interior. Figure 1 As shown, a discharge electrode 21 , an electrical insulating plate 23 , a ground plate 24 and a fan 26 are housed in the laser cavity 10 .

[0056] The discharge electrode 21 is an electrode for exciting the laser gas by discharge and is composed of a pair of electrodes 21a and 21b, each of which is arranged to face each other with a predetermined gap therebetween and with its longitudinal directions substantially parallel to each other.

[0057] The electrical insulating plate 23 is arranged to block the opening formed in the laser cavity 10. The electrical insulating plate 23 supports the electrode 21a. A plurality of feedthroughs 25 are embedded in the electrical insulating plate 23. The feedthroughs 25 electrically connect the high voltage terminal of the PPM 12 and the electrode 21a so that the high voltage supplied from the PPM 12 is applied to the electrode 21a.

[0058] The ground plate 24 supports the electrode 21 b. The ground plate 24 is connected to the laser cavity 10 via wiring. The ground plate 24 is grounded via wiring. The end portion of the ground plate 24 in the Z direction is fixed to the laser cavity 10.

[0059] Fan 26 is a cross-flow fan that circulates laser gas in laser cavity 10 to generate a high-speed laser gas flow in discharge space 30 between electrodes 21a and 21b. Fan 26 is arranged so that the longitudinal direction of discharge electrode 21 is substantially parallel to the longitudinal direction of fan 26.

[0060] The fan 26 has a rotating shaft 26a rotatably supported at both ends by the laser cavity 10. A motor 31 for rotating the fan 26 is connected to the laser cavity 10 via a magnetic coupling mechanism 28. As will be described later, the magnetic coupling mechanism 28 transmits the torque of the motor 31 to the rotating shaft 26a of the fan 26 using magnetic force.

[0061] The laser cavity 10 is provided with bearings 49 that rotatably support both ends of the rotating shaft 26a of the fan 26. Reference numeral 32 denotes a fixing portion that fixes one bearing 49 to the laser cavity 10.

[0062] Charger 11 is a high-voltage power source that supplies charging voltage to the charging capacitor included in PPM 12. PPM 12 includes a solid-state switch SW controlled by laser control unit 14. When solid-state switch SW switches from off to on, PPM 12 generates a high-voltage pulse using the electrical energy stored in the charging capacitor and applies it to discharge electrode 21.

[0063] When a high voltage is applied to discharge electrode 21, a discharge occurs between electrodes 21a and 21b. The energy from this discharge excites the laser gas within laser cavity 10, causing it to transition to a higher energy level. When the excited laser gas subsequently transitions to a lower energy level, it emits light of a wavelength corresponding to the energy level difference.

[0064] Windows 10a and 10b are provided at both ends of the laser cavity 10. Light generated in the laser cavity 10 is emitted to the outside of the laser cavity 10 through the windows 10a and 10b.

[0065] The laser resonator is composed of a narrowband module (LNM) 15 and an output coupling mirror (OC) 16 .

[0066] 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 cavity 10 through the window 10a and transmits the light toward the grating 15b.

[0067] Grating 15b is 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 light returning from grating 15b to laser cavity 10 via prism 15a is narrowed.

[0068] The output coupling mirror 16 transmits a portion of the light emitted from the laser cavity 10 through the window 10b and reflects the other portion to return it to the laser cavity 10. The surface of the output coupling mirror 16 is coated with a partial reflection film.

[0069] Light emitted from laser cavity 10 travels back and forth between bandwidth narrowing module 15 and output coupling mirror 16, being amplified each time it passes through discharge space 30 between electrodes 21a and 21b. A portion of the amplified light is output as pulsed laser light PL via output coupling mirror 16. Pulsed laser light PL is an example of "laser" in the technology disclosed herein.

[0070] 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 photosensor 13c.

[0071] Beam splitter 13a transmits the pulsed laser light PL with high transmittance and reflects the remaining 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 laser control unit 14.

[0072] Laser cavity 10 is provided with a laser gas supply device and a laser gas exhaust device (not shown). The laser gas supply device includes a valve and a flow control valve and is connected to a gas cylinder containing laser gas. The laser gas exhaust device includes a valve and an exhaust pump.

[0073] The pressure sensor 17 detects the gas pressure in the laser cavity 10 and outputs the detected value to the laser control unit 14 .

[0074] The laser control unit 14 is a processor that transmits and receives various signals to and from the exposure device control unit 3a provided in the exposure device 3. For example, the exposure device control unit 3a transmits to the laser control unit 14 a trigger signal related to the target pulse energy of the pulsed laser light PL output to the exposure device 3 and the target oscillation timing.

[0075] The laser control unit 14 centrally controls the operation of each component of the gas laser device 2 based on various signals transmitted from the exposure device control unit 3a, as well as the measured value of pulse energy, the detected value of gas pressure, and the like. For example, the laser control unit 14 determines the pressure of the laser gas within the laser cavity 10 based on the detected value of gas pressure and the charge voltage of the charger 11. The laser control unit 14 controls the laser gas supply device and the laser gas exhaust device to maintain the determined gas pressure.

[0076] 1.1.2 Structure of magnetic coupling mechanism and bearing

[0077] use Figure 2 and Figure 3 The magnetic coupling mechanism 28 and the bearing 49 of the comparative example will be described. Figure 2 It is a cross-sectional view taken along a YZ plane parallel to the axial direction AX of the rotation shaft 26 a of the magnetic coupling mechanism 28 . Figure 3 middle, Figure 3 (A) is a cross-sectional view of the magnetic coupling mechanism 28 along the YZ plane. Figure 3 (B) is Figure 3 The cross-sectional view along the line AA in (A) is a cross-sectional view taken along the line AA, which is a cross-sectional view taken along the YX plane perpendicular to the axial direction AX. Here, the axial direction AX is synonymous with the thrust direction of the bearing 49 and is sometimes referred to as the thrust direction below.

[0078] 1.1.2.1 Bearing structure

[0079] As an example, bearing 49 is a ball bearing, as is well known, and comprises an inner ring 49a fixed to rotating shaft 26a, an outer ring 49b fixed to laser cavity 10, and a plurality of rotating bodies 49c. Multiple grooves for accommodating rotating bodies 49c are formed on the outer circumferences of inner ring 49a and outer ring 49b, respectively. The rotating bodies 49c are rotatably held by inner ring 49a and outer ring 49b, with the inner and outer sides of the rotating bodies 49c being held in place. The rotating bodies 49c are, for example, spheres or cylinders.

[0080] Furthermore, a sealing member 47 is provided inside the laser cavity 10 relative to the bearing 49. The sealing member 47 is annular in shape and has a hole formed in the center thereof through which the rotating shaft 26a is inserted. A small gap is formed between the hole of the sealing member 47 and the outer peripheral surface of the rotating shaft 26a to prevent contact between the sealing member 47 and the rotating shaft 26a.

[0081] When the rotating shaft 26 a rotates, particles such as dust may be generated on the bearing 49 , and the density of the particles contained in the laser gas may increase. The sealing member 47 prevents the laser gas with increased particle density from entering the laser cavity 10 .

[0082] As an example, of the two bearings 49, the bearing 49 on the magnetic coupling mechanism 28 side is fixed to the side wall 10c of the laser cavity 10 via a fixing portion 10d. The other bearing 49 is fixed to the side wall 10c of the laser cavity 10 via a fixing portion 32. As an example, the fixing portion 32 is composed of a mounting portion 32a and a retaining portion 32b. The mounting portion 32a is a component for mounting the bearing 49. The retaining portion 32b holds the mounting portion 32a and secures the bearing 49 together with the mounting portion 32a to the side wall 10c of the laser cavity 10.

[0083] The retaining portion 32b has, for example, a cylindrical shape capable of accommodating the mounting portion 32a therein, thereby retaining the mounting portion 32a so that it can move freely in the axial direction AX. A spring 51 is disposed within the retaining portion 32b. The spring 51 biases the mounting portion 32a toward the bearing 49 on the magnetic coupling mechanism 28 side in the axial direction AX. The spring 51 biases the rotating shaft 26a, thereby stabilizing the rotating shaft 26a.

[0084] Furthermore, the holding portion 32 b also functions as a partition wall that prevents the laser gas from leaking to the outside of the holding portion 32 b.

[0085] 1.1.2.2 Structure of magnetic coupling mechanism

[0086] The magnetic coupling mechanism 28 utilizes magnetic force to transmit the driving force of the motor 31 to the rotating shaft 26a of the fan 26. The magnetic coupling mechanism 28 includes an inner rotor 42, an outer rotor 43, a shroud 44, and a bracket 46.

[0087] The inner rotor 42 is connected to the rotating shaft 26a of the fan 26. A portion of the rotating shaft 26a protrudes from the laser cavity 10, and the inner rotor 42 is fixed to the protruding portion. The inner rotor 42 has a cylindrical shape with a circular cross-section perpendicular to the axial direction AX of the rotating shaft 26a, and has an insertion portion at the center for inserting the rotating shaft 26a. A plurality of first magnets M1 are arranged along the outer peripheral surface of the inner rotor 42. The plurality of first magnets M1 are permanent magnets and are arranged at equal intervals in the circumferential direction around the rotating shaft 26a. The plurality of first magnets M1 are arranged with N poles and S poles alternating in the circumferential direction. As an example, the inner rotor 42 is an octapole type having 8 first magnets M1. The position of the first magnet M1 is fixed relative to the inner rotor 42.

[0088] The outer rotor 43 rotates due to the driving force of the motor 31, and the inner rotor 42 is driven to rotate by magnetic force. The outer rotor 43 is connected to the drive shaft 31a of the motor 31. As shown in the axial direction AX, the drive shaft 31a of the motor 31 is coaxial with the rotating shaft 26a of the fan 26 connected to the inner rotor 42. The outer rotor 43 is a cup-shaped container, with a cylindrical shape having a circular cross-section perpendicular to the drive shaft 31a.

[0089] More specifically, the outer rotor 43 has a cylindrical portion 43a that defines an internal space for accommodating the inner rotor 42. The cylindrical portion 43a is a bottomed cylindrical portion. Specifically, in the axial direction AX of the rotating shaft 26a, one end 43c on the laser cavity 10 side is open, and the other end on the motor 31 side has a bottom 43b.

[0090] The bottom 43b has an insertion opening into which the end of the drive shaft 31a on the rotating shaft 26a side is inserted, and the drive shaft 31a is fixed to the insertion opening. The outer rotor 43 is arranged with a gap between the end 43c and the fixing portion 10d of the laser cavity 10.

[0091] The inner diameter of the cylindrical portion 43a is larger than the outer diameter of the inner rotor 42. The outer rotor 43 accommodates the inner rotor 42 in its internal space, with the inner circumferential surface of the cylindrical portion 43a facing the outer circumferential surface of the inner rotor 42. More specifically, the inner rotor 42 is covered by a shroud 44, which will be described later, and the cylindrical portion 43a accommodates the inner rotor 42 while covered by the shroud 44.

[0092] In the cylindrical portion 43a, a plurality of second magnets M2 are arranged along the inner circumferential surface. The plurality of second magnets M2 are permanent magnets and are arranged at equal intervals in the circumferential direction around the rotating shaft 26a. The plurality of second magnets M2 are arranged with north poles and south poles alternately in the circumferential direction. The number of second magnets M2 is the same as that of first magnets M1, and each second magnet M2 is arranged so as to be opposite to the first magnet M1. The first magnet M1 and the second magnet M2 are arranged so that when one of the opposing magnets is an north pole, the other is an south pole, so as to generate an attractive force between the opposing magnets. When the inner rotor 42 is an octapole type, the outer rotor 43 is also an octapole type having eight second magnets M2. The position of the second magnet M2 is fixed relative to the outer rotor 43.

[0093] Furthermore, the first magnet M1 and the second magnet M2 have the same axial length (AX), i.e., the dimension in the thrust direction, and are positioned so that the first magnet M1 and the second magnet M2 face each other in the axial direction (AX). Furthermore, the first magnet M1 and the second magnet M2, each having different magnetic poles, generate an attractive force in a radial direction centered on the rotation axis 26a within the XY plane perpendicular to the rotation axis 26a. Hereinafter, the direction in which the attractive force is generated will also be referred to as the radial direction. The first magnet M1 and the second magnet M2 are radially arranged within a range where the attractive force interacts.

[0094] The bracket 46 is a fixing member for fixing the motor 31 to the laser cavity 10. The bracket 46 is fixed to the laser cavity 10 while accommodating the outer rotor 43. The bracket 46 is a cup-shaped container structure and has a cylindrical shape with a circular cross section perpendicular to the drive shaft 31a.

[0095] More specifically, bracket 46 is also cylindrical with a bottom, similar to outer rotor 43, and includes a cylindrical portion 46a that accommodates outer rotor 43. Cylindrical portion 46a is open at one end 46c on the laser cavity 10 side in the axial direction AX, and has a bottom 46b at the other end on the motor 31 side.

[0096] The inner diameter of the cylindrical portion 46a is larger than the outer diameter of the outer rotor 43. The cylindrical portion 46a accommodates the outer rotor 43 in its internal space, with its inner peripheral surface facing the outer peripheral surface of the outer rotor 43. An end 46c of the cylindrical portion 46a on the laser cavity 10 side is fixed to the side wall 10c of the laser cavity 10.

[0097] The bottom portion 46b is formed with a through-hole 46d through which the drive shaft 31a of the motor 31 is rotatably inserted. The motor 31 is fixed to the outer surface of the bottom portion 46b of the bracket 46 with the drive shaft 31a inserted through the through-hole 46d.

[0098] The shield 44 houses the inner rotor 42. The laser gas in the laser cavity 10 flows into the shield 44. The shield 44 functions as a partition wall that prevents the laser gas from leaking to the outside of the shield 44.

[0099] The shield 44 is a cup-shaped container, cylindrical in shape with a circular cross-section perpendicular to the rotation axis 26a. More specifically, the shield 44 includes a cylindrical portion 44a that defines the internal space housing the inner rotor 42. The end of the cylindrical portion 44a facing the side wall 10c is open, and the end facing the motor 31 forms the bottom. The shield 44 is fixed to the laser cavity 10 with the open end of the cylindrical portion 44a in contact with the side wall 10c, thereby airtightly housing the inner rotor 42.

[0100] The inner circumference of the shield 44 faces the first magnet M1, and the outer circumference faces the second magnet M2. The shield 44 is positioned between the first magnet M1 and the second magnet M2. Predetermined gaps are provided between the outer circumference of the cylindrical portion 44a and the inner circumference of the cylindrical portion 43a of the outer rotor 43, and between the inner circumference of the cylindrical portion 44a and the outer circumference of the inner rotor 42.

[0101] 1.2 Action

[0102] When the drive shaft 31a of the motor 31 is rotated, the outer rotor 43 connected to the drive shaft 31a rotates. The second magnets M2 of the outer rotor 43 and the first magnets M1 of the inner rotor 42 generate a magnetic attraction force in the radial direction, attracting each other. Therefore, when the outer rotor 43 rotates, the magnetic attraction force causes the inner rotor 42 to rotate. The north and south poles of the second magnets M2 and first magnets M1 are arranged alternately in the circumferential direction. Therefore, for example, if the rotational phase of the outer rotor 43 and the inner rotor 42 is offset, that is, the relative positional relationship of the second magnets M2 and first magnets M1 in the circumferential direction is offset, a magnetic repulsive force is generated when the magnets of the same poles face each other. This repulsive force maintains the phase rotation of the outer rotor 43 and the inner rotor 42.

[0103] The rotation of the inner rotor 42 rotates the fan 26 . The rotation of the fan 26 causes the laser gas to circulate in the laser cavity 10 , generating a laser gas flow in the discharge space 30 of the discharge electrode 21 .

[0104] The laser control unit 14 supplies a charging voltage corresponding to the target pulse energy received from the exposure device 3 to the PPM 12 via the charger 11. When a trigger signal is input from the exposure device 3, the laser control unit 14 applies a pulsed high voltage to the discharge electrode 21 via the PPM 12. Application of the high voltage to the discharge electrode 21 excites the laser gas, causing laser light to be emitted. The laser light reciprocates between the band-narrowing module 15 and the output coupling mirror 16, amplifying the laser light each time it passes through the discharge space 30. Furthermore, the laser light is narrowed by the band-narrowing module 15, and the narrowed pulsed laser light PL is emitted from the output coupling mirror 16 toward the exposure device 3.

[0105] The rotation of the fan 26 generates a laser gas flow in the discharge space 30 , thereby stabilizing the excitation of the laser gas in the discharge space 30 and supplying stable pulse laser light PL to the exposure device 3 .

[0106] 1.3 Topics

[0107] Figure 4 (A) shows the relative positional relationship between the inner rotor 42 and the outer rotor 43 in the axial direction AX, i.e., the thrust direction, in its initial state. This initial state is when only radial attractive force is generated between the first magnet M1 and the second magnet M2, and no magnetic attractive force is generated in the thrust direction. More specifically, this is when the thrust-direction centers of the first magnet M1 and the second magnet M2 are aligned.

[0108] Figure 4 (B) shows a situation where a positional deviation ΔDr is generated relative to the initial state in the relative positional relationship of the inner rotor 42 and the outer rotor 43 in the thrust direction. Such a positional deviation ΔDr is caused by assembly errors during assembly of the magnetic coupling mechanism 28, heat generated during operation, and thermal expansion of each part due to the ambient temperature. Figure 4 (B) shows the position of the outer rotor 43 from Figure 4 The state shown in (A) is a state after the laser cavity 10 side is moved by ΔDr.

[0109] The position of the first magnet M1 is fixed relative to the inner rotor 42, and the position of the second magnet M2 is fixed relative to the outer rotor 43. Figure 4 As shown in FIG. 5(B), when a positional deviation ΔDr occurs, a positional deviation ΔDm corresponding to ΔDr also occurs in the thrust direction of the first magnet M1 and the second magnet M2.

[0110] When the positional deviation ΔDm occurs, the first magnet M1 and the second magnet M2 generate a force Fs in the direction to cancel the positional deviation ΔDm due to the magnetic attraction. The force Fs is applied in the thrust direction of the bearing 49 and continues to be applied to the bearing 49 as long as the positional deviation ΔDr between the inner rotor 42 and the outer rotor 43 is not eliminated. Figure 4 Compared to the initial state shown in (A), the friction of the bearing 49 is increased. The increase in friction has problems such as causing heat generation and noise increase in the bearing 49 and shortening the life of the bearing 49.

[0111] 2. First Implementation

[0112] Next, refer to Figure 5 and Figure 6 The magnetic coupling mechanism 28A according to the first embodiment of the present disclosure will be described. Figure 5 middle, Figure 5(A) is a cross-sectional view of the magnetic coupling mechanism 28A taken along the YZ plane. Figure 5 (B) is the AA line of the magnetic coupling mechanism 28A (see Figure 5 (A)) Cross-sectional view of the XY plane.

[0113] In addition, the gas laser device including the magnetic coupling mechanism 28A of the first embodiment is identical to the gas laser device 2 shown in the comparative example except for the magnetic coupling mechanism 28A. The gas laser device including the magnetic coupling mechanism 28A is an example of a "gas laser device" in the technology disclosed herein. Furthermore, a laser cavity device including the laser cavity 10, the fan 26, and the magnetic coupling mechanism 28A is an example of a "laser cavity device" in the technology disclosed herein.

[0114] The magnetic coupling mechanism 28A of the first embodiment differs from the magnetic coupling mechanism 28 of the comparative example in that the first magnet M1 is movable in the thrust direction relative to the inner rotor 42. Therefore, the same reference numerals are used for the same components as those described above, and redundant descriptions are omitted unless otherwise specified.

[0115] 2.1 Structure

[0116] like Figure 5 As shown, in the magnetic coupling mechanism 28A, the first magnet M1 is movable in the thrust direction of the bearing 49 due to magnetic attraction. In the first embodiment, a storage chamber SP is provided within the inner rotor 42 to accommodate the first magnet M1 so that it can move in the thrust direction. The storage chamber SP has a larger dimension in the thrust direction, that is, a greater length in the thrust direction, than the first magnet M1. Therefore, the first magnet M1 can move in the thrust direction within the storage chamber SP.

[0117] As specific dimensions, for example, the dimension of the storage chamber SP in the thrust direction is 1 mm to 4 mm larger than that of the first magnet M1. Furthermore, for example, the dimension of the storage chamber SP in the radial direction perpendicular to the thrust direction, i.e., the radial thickness, is 0.1 mm to 0.5 mm larger than that of the first magnet M1.

[0118] In the first embodiment, the second magnet M2 is fixed to the outer rotor 43 and cannot move relative to the outer rotor 43 in the thrust direction. That is, of the first magnet M1 and the second magnet M2, only the first magnet M1 can move in the thrust direction. Furthermore, the first magnet M1 and the second magnet M2 have the same dimensions in the thrust direction.

[0119] Inner rotor 42, which movably holds first magnet M1, is formed, for example, from a non-magnetic material. Furthermore, inner rotor 42 is formed from a corrosion-resistant material that is less susceptible to corrosion by fluorine gas. For example, stainless steel such as SUS316 or SUS316L is used as the material for inner rotor 42. For example, outer rotor 43 is formed from a magnetic metal, such as steel such as SM490.

[0120] 2.2 Action and Effect

[0121] use Figure 6 The operation and effects of the magnetic coupling mechanism 28A according to the first embodiment will be described. Figure 6 Compared with the comparative example Figure 4 correspond, Figure 6 (A) shows the initial state of the relative positional relationship between the inner rotor 42 and outer rotor 43 of the magnetic coupling mechanism 28A in the thrust direction. In this initial state, there is no positional offset ΔDr, the thrust-direction centers of the first magnet M1 and the second magnet M2 are aligned, and magnetic attraction occurs only in the radial direction. Figure 6 (B) shows a state where a positional deviation ΔDr occurs between the inner rotor 42 and the outer rotor 43 in the thrust direction due to assembly errors, thermal expansion, and the like of the magnetic coupling mechanism 28A.

[0122] In the magnetic coupling mechanism 28A, the first magnet M1 can move in the thrust direction by the magnetic attraction force. Figure 6 As shown in (B), even when a positional deviation ΔDr occurs between the inner rotor 42 and the outer rotor 43 in the thrust direction, the first magnet M1 moves in the thrust direction to eliminate the positional deviation ΔDm between the first magnet M1 and the second magnet M2 in the thrust direction (in Figure 6 (B) represents ΔDm=0). That is, Figure 6 As shown in (B), the first magnet M1 moves in the storage chamber SP in a direction to eliminate the positional deviation ΔDm from the second magnet M2 due to the magnetic attraction between the first magnet M1 and the second magnet M2. Figure 6 In (B), the second magnet M2 moves toward the laser cavity 10 together with the outer rotor 43 , and therefore the first magnet M1 also moves toward the laser cavity 10 due to the magnetic attraction.

[0123] Thus, in the magnetic coupling mechanism 28A, even if a positional deviation ΔDr occurs between the inner rotor 42 and the outer rotor 43, the positional deviation ΔDm is eliminated by the movement of the first magnet M1 in the thrust direction. Figure 4 The force Fs shown in (B) is continuously applied to the bearing 49. This suppresses the increase in friction of the bearing 49, and suppresses the heat generation, noise, and life reduction of the bearing 49 caused by the increase in friction.

[0124] Furthermore, since the inner rotor 42 is formed of a nonmagnetic material, the inner rotor 42 is prevented from being magnetized by the first magnets M1. If the inner rotor 42 is magnetized, a magnetic attraction force is generated between the inner rotor 42 and the first magnets M1, which acts as a resistance to the movement of the first magnets M1. Forming the inner rotor 42 of a nonmagnetic material can suppress the resistance to the movement of the first magnets M1.

[0125] Furthermore, the inner rotor 42 is formed of a corrosion-resistant material that is not easily corroded by fluorine gas, and thus it is possible to suppress corrosion caused by the laser gas leaking from the laser cavity 10 into the shield 44 .

[0126] In the first embodiment, the second magnets M2 are fixed to the outer rotor 43 , so movement resistance of the second magnets M2 due to magnetization does not become a problem. However, the outer rotor 43 may be formed of a non-magnetic material instead of a magnetic metal.

[0127] 2.3 Modification 1 of the First Embodiment

[0128] 2.3.1 Modification 1

[0129] Figure 7 Modification 1 of the first embodiment shown here replaces the first magnet M1 with a second magnet M2 that is movable in the thrust direction by magnetic attraction. In the magnetic coupling mechanism 28A of Modification 1, a housing SP is provided within the outer rotor 43 to accommodate the second magnet M2 so that it can move in the thrust direction. This structure, even with the second magnet M2 being movable, achieves the same effect as the case where the first magnet M1 is movable, suppressing increases in friction on the bearing 49.

[0130] Furthermore, when the second magnets M2 are movable, the outer rotor 43 is preferably formed of a non-magnetic material. This is because the resistance to movement of the second magnets M2 caused by magnetization of the outer rotor 43 can be suppressed.

[0131] Furthermore, in a configuration in which the second magnet M2 can be moved relative to the outer rotor 43 as in Modification 1, Figure 6 Compared with the case shown in FIG. 1 , there is an advantage that the friction between the second magnet M2 and the inner wall surface of the storage chamber SP during movement is reduced, and the second magnet M2 can be easily moved. The reason is as follows.

[0132] like Figure 8As shown, consider the case where the outer rotor 43 moves toward the laser cavity 10 due to thermal expansion, resulting in a positional offset ΔDr. In this case, the second magnet M2 moves in a direction that cancels the positional offset with the first magnet M1, that is, in a direction opposite to the laser cavity 10. The magnetic attraction generated by the second magnet M2 at this time can be decomposed into a radial component, force Fg1, and a thrust component, force Fg2. Force Fg3 is the resultant force of forces Fg1 and Fg2. The second magnet M2 generates a friction force Ffr against the inner wall surface of the storage chamber SP on the first magnet M1 side, in the direction opposite to the direction of movement of the second magnet M2, that is, in the direction opposite to the thrust force Fg2. The friction force Ffr acts as a resistance to the movement of the second magnet M2 in the thrust direction. The greater the radial force Fg1, the greater the friction force Ffr.

[0133] Furthermore, the rotation of the outer rotor 43 generates a centrifugal force Fc on the second magnet M2. This centrifugal force Fc acts in a direction opposite to the radial force Fg1 acting on the second magnet M2, thereby reducing the friction force Ffr. When the friction force Ffr decreases, the resistance to movement of the second magnet M2 decreases, facilitating movement of the second magnet M2.

[0134] In contrast, Figure 6 As shown, when the first magnet M1 of the inner rotor 42 moves, the radial force based on magnetism acting on the first magnet M1 acts in the direction of the second magnet M2 toward the outer rotor 43, and therefore has the same direction as the centrifugal force acting on the first magnet M1. Therefore, the centrifugal force acting on the first magnet M1 results in an increase in friction. Figure 6 Compared with the situation shown, Figure 8 Modification 1 shown is more advantageous from the viewpoint of reducing friction.

[0135] 2.3.2 Modification 2

[0136] Figure 9 The second modification of the first embodiment shown is an example in which oil 52 is sealed in the storage chamber SP. Figure 9 , the example shows the storage chamber SP of the outer rotor 43 housing the second magnet M2. As an example, the viscosity of the oil 52 is ISO_VG10 to VG100. Since the inner wall of the storage chamber SP is lubricated by the oil 52, the movement resistance of the second magnet M2 within the storage chamber SP is reduced compared to a case without oil 52. Furthermore, the flow resistance of the oil 52 suppresses the rapid movement of the second magnet M2, and is expected to reduce vibration of the second magnet M2 within the storage chamber SP.

[0137] In addition, Figure 9 In the description, the accommodation chamber SP of the outer rotor 43 is taken as an example, but the present invention can also be applied to the accommodation chamber SP of the inner rotor 42.

[0138] 3. Second embodiment

[0139] 3.1 Structure

[0140] like Figure 10 As shown, the magnetic coupling mechanism 28B of the second embodiment replaces the arrangement of the housing SP for the second magnet M2 in the outer rotor 43 with a moving mechanism that moves the second magnet M2 via a linear guide 56 and a carriage 57. Figure 7 Since the modified example 1 is the same as the first embodiment shown, the description will focus on the differences.

[0141] The cylindrical portion 43a of the outer rotor 43 is arranged on the outer circumference of the inner rotor 42. A linear guide 56 is provided on the inner circumferential surface of the cylindrical portion 43a, that is, at a position facing the outer circumferential surface of the inner rotor 42. The carriage 57 is held movably relative to the linear guide 56 by being engaged with the linear guide 56. The second magnet M2 is fixed to the carriage 57 and moves with the carriage 57. In this way, the linear guide 56 guides the movement of the second magnet M2 in the thrust direction via the carriage 57 and retains the second magnet M2.

[0142] In the magnetic coupling mechanism 28B, the linear guide 56 and the carriage 57 are preferably formed of non-magnetic materials in addition to the outer rotor 43. By suppressing magnetization of the linear guide 56 and the carriage 57, the movement resistance of the magnetic second magnet M2 can be suppressed.

[0143] 3.2 Action and Effect

[0144] In the second embodiment, a positional deviation ΔDr occurs between the inner rotor 42 and the outer rotor 43 (see Figure 8 In the case of the second magnet M2 moving in the thrust direction in a direction to eliminate the positional offset with the first magnet M1. In the second embodiment, the second magnet M2 is movably held by the linear guide 56, so the movement resistance caused by friction is reduced compared to the case where the second magnet M2 is accommodated in the accommodation chamber SP.

[0145] Furthermore, in the second embodiment, the second magnet M2 is held by the linear guide 56 via the carriage 57. However, the second magnet M2 may be held directly by the linear guide 56 without the carriage 57. Of course, providing the carriage 57 may also provide advantages such as easier processing. In such cases, providing the carriage 57 is preferred.

[0146] In addition, Figure 10In the description, the second magnet M2 of the outer rotor 43 is taken as an example. However, a linear guide 56 may be provided on the outer peripheral surface of the inner rotor 42 to hold the first magnet M1.

[0147] 4. Third Implementation

[0148] exist Figure 11 In the magnetic coupling mechanism 28C of the third embodiment shown, both the first magnet M1 and the second magnet M2 are movable in the thrust direction due to magnetic attraction. Each of the inner rotor 42 and the outer rotor 43 is provided with a housing SP that accommodates the first magnet M1 or the second magnet M2 so that they can move. The first magnet M1 and the second magnet M2 move in the thrust direction within their respective housing chambers SP.

[0149] In such a structure, the first magnet M1 and the second magnet M2 are also offset to the cancellation position by ΔDm (refer to Figure 6 Therefore, the positional deviation ΔDr (refer to Figure 6 etc.) caused by the increase in the friction of the bearing 49.

[0150] 5. Other variations

[0151] The gas laser device 2 using the discharge electrode 21 of the first and second embodiments is a narrowband laser device, but is not limited thereto and may also be a gas laser device that outputs natural oscillation light. For example, a high reflection mirror may be provided instead of the narrowband module 15.

[0152] In addition, in each of the above embodiments, the gas laser device 2 is an excimer laser device. However, it may alternatively be an F2 molecular laser device using a laser gas containing fluorine gas and a buffer gas. In other words, the gas laser device 2 of the present disclosure may be any gas laser device that excites the laser gas containing fluorine through discharge.

[0153] 6. Method for manufacturing electronic devices

[0154] Figure 12 An 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 reduces and projects the pulsed laser light PL transmitted through the reticle, forming an image on a workpiece (not shown) placed on workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0155] Exposure apparatus 100 uses synchronous parallel movement of 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 process, semiconductor devices can be manufactured through multiple steps. Semiconductor devices are an example of "electronic devices" in this disclosure.

[0156] exist Figure 12 The gas laser device 2 shown uses at least one of the magnetic coupling mechanisms 28A, 28B, and 28C of the above-described embodiments.

[0157] 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.

[0158] 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.

[0159] The terms used in this specification and the appended claims as a whole should be interpreted as "non-limiting" terms. For example, the terms "include" or "included" should be interpreted as "not limited to what is recorded as included". The term "having" should be interpreted as "not limited to what is recorded as having". In addition, the modifier "one" recorded in this specification and the appended claims should be interpreted as meaning "at least one" or "one or more". In addition, the term "at least one of A, B and C" should be interpreted as "A", "B", "C", "A+B", "A+C", "B+C" or "A+B+C", and should be interpreted as also including combinations of them with parts other than "A", "B" and "C".

Claims

1. A laser cavity device comprising: a laser cavity containing laser gas; a fan disposed inside the laser cavity to circulate the laser gas; a bearing that rotatably supports a rotating shaft of the fan; as well as A magnetic coupling mechanism that transmits the driving force of the motor to the rotating shaft of the fan using magnetic force, The magnetic coupling mechanism comprises: an inner rotor connected to the rotating shaft of the fan and provided with a first magnet; as well as an outer rotor connected to the drive shaft of the motor and having a second magnet disposed outside the inner rotor at a position opposing the first magnet, wherein the outer rotor is rotated by the driving force of the motor and driven to rotate the inner rotor by magnetic attraction. At least one of the first magnet and the second magnet is movable in the thrust direction of the bearing by magnetic attraction.

2. The laser cavity device according to claim 1, wherein: A housing chamber is provided inside at least one of the inner rotor and the outer rotor, and the housing chamber houses the first magnet or the second magnet so as to be movable in the thrust direction.

3. The laser cavity device according to claim 2, wherein: A dimension of the accommodation chamber in the thrust direction that is larger than that of the first magnet or the second magnet is in a range of 1 mm to 4 mm.

4. The laser cavity device according to claim 2, wherein: The dimension of the accommodating chamber in a radial direction perpendicular to the thrust direction is larger than that of the first magnet or the second magnet by 0.1 mm to 0.5 mm.

5. The laser cavity device according to claim 2, wherein: At least one of the inner rotor that movably holds the first magnet and the outer rotor that movably holds the second magnet is formed of a non-magnetic material.

6. The laser cavity device according to claim 2, wherein: Oil is sealed in at least one of the accommodation chamber provided in the inner rotor and the accommodation chamber provided in the outer rotor.

7. The laser cavity device according to claim 6, wherein: The viscosity of the oil is ISO_VG10 to VG100.

8. The laser cavity device according to claim 1, wherein: The outer rotor has a cylindrical portion arranged on the outer periphery of the inner rotor. A linear guide is provided on the inner peripheral surface of the cylindrical portion. The linear guide guides movement of the second magnet in the thrust direction and holds the second magnet.

9. The laser cavity device according to claim 8, wherein: The outer rotor and the linear guide are made of non-magnetic materials.

10. The laser cavity device according to claim 1, wherein: One of the first magnet and the second magnet is movable.

11. The laser cavity device according to claim 10, wherein: The second magnet is movable.

12. The laser cavity device according to claim 1, wherein: Both the first magnet and the second magnet are movable.

13. The laser cavity device according to claim 1, wherein: The first magnet and the second magnet have the same size in the thrust direction.

14. A gas laser device comprising: a laser cavity accommodating a discharge electrode and laser gas; a fan disposed inside the laser cavity to circulate the laser gas; a bearing that rotatably supports a rotating shaft of the fan; a motor that drives the fan; and a magnetic coupling mechanism that transmits the driving force of the motor to the rotating shaft of the fan using magnetic force, The gas laser device generates laser light by exciting the laser gas through discharge. The magnetic coupling mechanism comprises: an inner rotor connected to the rotating shaft of the fan and provided with a first magnet; and an outer rotor connected to the drive shaft of the motor and having a second magnet disposed outside the inner rotor at a position opposing the first magnet, wherein the outer rotor is rotated by the driving force of the motor and driven to rotate the inner rotor by magnetic attraction. At least one of the first magnet and the second magnet is movable in the thrust direction of the bearing by magnetic attraction.

15. A method for manufacturing an electronic device, comprising the following steps: Laser is generated by a gas laser device, Outputting the laser to an exposure device, exposing the photosensitive substrate to the laser in the exposure device to manufacture electronic devices, The gas laser device comprises: a laser cavity accommodating a discharge electrode and laser gas; a fan disposed inside the laser cavity to circulate the laser gas; a bearing that rotatably supports a rotating shaft of the fan; a motor that drives the fan; and a magnetic coupling mechanism that transmits the driving force of the motor to the rotating shaft of the fan using magnetic force, The gas laser device generates the laser light by exciting the laser gas through discharge. The magnetic coupling mechanism comprises: an inner rotor connected to the rotating shaft of the fan and provided with a first magnet; and an outer rotor connected to the drive shaft of the motor and having a second magnet disposed outside the inner rotor at a position opposing the first magnet, wherein the outer rotor is rotated by the driving force of the motor and driven to rotate the inner rotor by magnetic attraction. At least one of the first magnet and the second magnet is movable in the thrust direction of the bearing by magnetic attraction.

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