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

Abstract

The invention relates to a laser chamber, a gas laser apparatus, and a method for manufacturing an electronic device. A laser chamber according to one aspect of the present disclosure accommodates a pair of electrodes disposed so as to face each other in a first direction, and is configured so as to be able to introduce a laser gas, at least one of the pair of electrodes including: a discharge unit extending in a second direction orthogonal to the first direction; and a shoulder portion disposed so as to surround a side surface of the discharge portion, the surface of the discharge portion including: a discharge surface extending in the second direction; and an end surface that is a part of a rotating elliptical surface and that is provided at an end of the discharge section in the second direction.

Description

Technical Field

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

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

[0003] The spectral line width of the spontaneous oscillation light of a KrF excimer laser device and an ArF excimer laser device is as wide as 350 pm to 400 pm. Therefore, when a projection lens is made of a material that transmits ultraviolet light such as KrF and ArF lasers, chromatic aberration may occur. As a result, the resolution may be reduced. Therefore, it is necessary to narrow the spectral line width of the laser output from the gas laser device to such an extent that chromatic aberration can be ignored. Therefore, in the laser resonator of the gas laser device, in order to narrow the spectral line width, a narrowing module (Line Narrowing Module: LNM) including a narrowing element (etalon, grating, etc.) is sometimes provided. A gas laser device whose spectral line width has been narrowed is called a narrowed gas laser device.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: International Publication No. 2023 / 127286

[0007] Patent Document 2: Japanese Utility Model Laid-Open No. 59-14502

[0008] Patent Document 3: US Patent No. 10074953 Specification Summary of the Invention

[0009] A laser chamber according to one aspect of the present disclosure houses a pair of electrodes arranged to face each other in a first direction and is configured to be able to introduce a laser gas. At least one of the pair of electrodes includes: a discharge portion that extends in a second direction orthogonal to the first direction; and a shoulder portion that is arranged so as to surround the side surface of the discharge portion. The surface of the discharge portion includes: a discharge surface that extends in the second direction; and an end surface that is provided at the end of the discharge portion in the second direction, and the end surface is a part of a rotational ellipsoidal surface.

[0010] A gas laser device according to an aspect of the present disclosure includes: a laser chamber that houses a pair of electrodes arranged to face each other in a first direction and is configured to be able to introduce a laser gas; a power supply device connected to the pair of electrodes; and a processor that controls the power supply device to discharge the pair of electrodes. At least one of the pair of electrodes includes: a discharge portion that extends in a second direction orthogonal to the first direction; and a shoulder portion that is arranged to surround the side surface of the discharge portion. The surface of the discharge portion includes: a discharge surface that extends in the second direction; and an end surface that is provided at an end of the discharge portion in the second direction, and the end surface is a part of a rotational ellipsoidal surface.

[0011] A method for manufacturing an electronic device according to an aspect of the present disclosure includes the following steps: introducing a laser gas into the laser chamber of a gas laser device; generating a laser by the gas laser device; outputting the laser to an exposure device; and exposing the laser on a photosensitive substrate in the exposure device to manufacture an electronic device. The gas laser device includes: a laser chamber that houses a pair of electrodes arranged to face each other in a first direction and is configured to be able to introduce a laser gas; a power supply device connected to the pair of electrodes; and a processor that controls the power supply device to discharge the pair of electrodes. At least one of the pair of electrodes includes: a discharge portion that extends in a second direction orthogonal to the first direction; and a shoulder portion that is arranged to surround the side surface of the discharge portion. The surface of the discharge portion includes: a discharge surface that extends in the second direction; and an end surface that is provided at an end of the discharge portion in the second direction, and the end surface is a part of a rotational ellipsoidal surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Hereinafter, several embodiments of the present disclosure will be described with reference to the drawings only by way of example.

[0013] Figure 1 It is a side view schematically showing the structure of a gas laser device of a comparative example.

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

[0015] Figure 3 It is a cross-sectional view of a cathode electrode of a comparative example viewed from the Z direction.

[0016] Figure 4 It is a side view of a cathode electrode of a comparative example viewed from the X direction.

[0017] Figure 5 It is a cross-sectional view schematically showing the structure of a laser chamber of the first embodiment.

[0018] Figure 6 It is a perspective view schematically showing the cathode electrode of the first embodiment.

[0019] Figure 7 It is a plan view schematically showing the end portion of the cathode electrode of the first embodiment.

[0020] Figure 8 It shows along Figure 7 a cross-sectional view of the A-A line.

[0021] Figure 9 It shows along Figure 7 a cross-sectional view of the B-B line.

[0022] Figure 10 It is a diagram for explaining a rotational ellipsoidal surface.

[0023] Figure 11 It is a side view of the cathode electrode of the first embodiment and the comparative example observed from the X direction.

[0024] Figure 12 It is a cross-sectional view of the cathode electrode of the second embodiment observed from the Z direction.

[0025] Figure 13 It is a cross-sectional view of the cathode electrode of the second embodiment observed from the X direction.

[0026] Figure 14 It is a side view of the cathode electrode of the third embodiment observed from the Z direction.

[0027] Figure 15 It is a side view of the cathode electrode of the third embodiment observed from the X direction.

[0028] Figure 16 It is a side view of the anode electrode of the fourth embodiment observed from the Z direction.

[0029] Figure 17 It is a side view of the anode electrode of the fourth embodiment observed from the X direction.

[0030] Figure 18 It is a diagram schematically showing a structural example of an exposure apparatus. Detailed implementation manners

[0031] <Content>

[0032] 1. Comparative example

[0033] 1.1 Structure

[0034] 1.2 Operation

[0035] 1.3 Problems

[0036] 2. First embodiment

[0037] 2.1 Structure

[0038] 2.2 Operation

[0039] 2.3 Function and Effect

[0040] 3. Second Embodiment

[0041] 3.1 Structure

[0042] 3.2 Operation

[0043] 3.3 Function and Effect

[0044] 4. Third Embodiment

[0045] 4.1 Structure

[0046] 4.2 Operation

[0047] 4.3 Function and Effect

[0048] 5. Fourth Embodiment

[0049] 5.1 Structure

[0050] 5.2 Operation

[0051] 5.3 Function and Effect

[0052] 6. Method for Manufacturing an Electronic Device

[0053] 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 operations described in the embodiments are not necessarily all essential as the structures and operations of the present disclosure. Furthermore, the same reference numerals are assigned to the same components, and repeated descriptions are omitted.

[0054] 1. Comparative Example

[0055] First, a comparative example of the present disclosure will be described. The comparative example of the present disclosure is a manner known only to the applicant and is not a publicly known example recognized by the applicant himself.

[0056] 1.1 Structure

[0057] Use Figure 1 And Figure 2 To describe the structure of the gas laser device 2 of the comparative example. Figure 1 Schematically shows the structure of the gas laser device 2. Figure 2 Is a cross-sectional view of the laser chamber 10 shown when viewed from the Z direction. The gas laser device 2 is a discharge-excited gas laser device that excites a laser gas by discharge, for example, an excimer laser device. Figure 1

[0058] Figure 1 In Figure 1In this case, the traveling direction of the pulsed laser PL output from the gas laser device 2 is set as the Z direction. The discharge direction described later is set as the Y direction. The Y direction is orthogonal to the Z direction. In addition, the direction orthogonal to the Y direction and the Z direction is set as the X direction. Further, the Y direction corresponds to the "first direction" related to the technology of the present disclosure. The Z direction corresponds to the "second direction" related to the technology of the present disclosure. The X direction corresponds to the "third direction" related to the technology of the present disclosure. In addition, the pulsed laser PL is an example of the "laser" related to the technology of the present disclosure.

[0059] In Figure 1 this case, the gas laser device 2 includes a laser chamber 10, a charger 11, a pulse power module (PPM) 12, a processor 14, a pressure sensor 17, and a laser resonator. The laser resonator is composed of a narrowbanding module 15 and an output coupling mirror 16.

[0060] The laser chamber 10 is, for example, a metal container made of aluminum metal with nickel plating on its surface. As Figure 1 and Figure 2 shown, a main electrode 20, a ground plate 21, a wiring 22, a fan 23, a heat exchanger 24, and a preionization electrode 19 are provided inside the laser chamber 10. The preionization electrode 19 includes a preionization outer electrode 19a, a dielectric tube 19b, and a preionization inner electrode 19c.

[0061] Inside the laser chamber 10, a laser gas containing fluorine is introduced 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.

[0062] And an opening is formed in the laser chamber 10. In the laser chamber 10, an insulating plate 26 embedded with a feedthrough portion 25 is installed in a manner to block the opening, with an O-ring (not shown) interposed therebetween. The PPM 12 is disposed on the insulating plate 26. The laser chamber 10 is grounded.

[0063] The PPM 12 includes a charging capacitor (not shown) and is connected to the main electrode 20 via a feedthrough 25. The PPM 12 includes a switch SW for discharging the main electrode 20. The charger 11 is connected to the charging capacitor of the PPM 12. Hereinafter, the discharge generated at the main electrode 20 is referred to as the main discharge. The PPM 12 is an example of the "power supply device" of the technology of the present disclosure.

[0064] 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 to face each other in the Y direction. The space between the cathode electrode 20a and the anode electrode 20b is called the discharge space 29. The surface of the cathode electrode 20a on the side opposite to the discharge space 29 is supported by an electrical insulating plate 26 and connected to a feedthrough 25. The surface of the anode electrode 20b on the side opposite to the discharge space 29 is supported by a ground plate 21.

[0065] The ground plate 21 is connected to the laser chamber 10 via a wiring 22. The laser chamber 10 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 laser chamber 10.

[0066] The fan 23 is a cross-flow fan for circulating the laser gas inside the laser chamber 10. A motor 23a for rotationally driving the fan 23 is connected to the laser chamber 10. The heat exchanger 24 performs heat exchange between the refrigerant supplied to the inside of the heat exchanger 24 and the laser gas.

[0067] A laser gas supply device (not shown) and a laser gas exhaust device are connected to the laser chamber 10. The laser gas supply device includes valves and a flow control valve and is connected to a gas cylinder storing the laser gas. The laser gas exhaust device includes valves and an exhaust pump.

[0068] Windows 10a and 10b for emitting the light generated inside the laser chamber 10 to the outside are provided at the ends of the laser chamber 10. The laser chamber 10 is arranged such that the optical path of the optical resonator passes through the discharge space 29 and the windows 10a and 10b.

[0069] The narrowbanding module 15 includes a prism 15a and a grating 15b. The prism 15a transmits the light emitted from the laser chamber 10 via the window 10a so as to expand the beam width and then directs it toward the grating 15b side.

[0070] The grating 15b is arranged in a Littrow configuration where the incident angle and the diffraction angle are the same angle. The grating 15b is a wavelength selection element that selectively extracts the light near a specific wavelength according to the diffraction angle. The spectral width of the light returned from the grating 15b to the laser chamber 10 via the prism 15a is narrowed.

[0071] The output coupler 16 transmits a part of the light emitted from the laser chamber 10 via the window 10b and reflects the other part back to the laser chamber 10. A partial reflection film is coated on the surface of the output coupler 16.

[0072] The light emitted from the laser chamber 10 reciprocates between the narrowbanding module 15 and the output coupling mirror 16 and is amplified each time it passes through the discharge space 29. A part of the amplified light is output as pulsed laser PL via the output coupling mirror 16.

[0073] The pressure sensor 17 detects the air pressure inside the laser chamber 10 and outputs the detected value to the processor 14. The processor 14 determines the air pressure of the laser gas inside the laser chamber 10 based on the detected value of the air pressure and the charging voltage of the charger 11.

[0074] The charger 11 is a high-voltage power supply that supplies a 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 changes from off to on, the PPM 12 generates a high-voltage pulse using the electric energy held in the charging capacitor and applies it to the main electrode 20.

[0075] 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 processor 14 includes a storage device storing a control program and an arithmetic device such as a CPU (Central Processing Unit) that executes the control program. For example, the processor 14 uniformly controls the operations of the respective components of the gas laser device 2 based on various signals sent from the exposure device controller 110, the detected value of the air pressure, etc.

[0076] Use Figure 3 and Figure 4 to illustrate the structure of the cathode electrode 20a of the comparative example. Figure 3 is a cross-sectional view of the cathode electrode 20a of the comparative example viewed from the Z direction. Figure 4 is a side view of the cathode electrode 20a of the comparative example viewed from the X direction.

[0077] As Figure 3 shown, the cathode electrode 20a includes a discharge part 27 and a shoulder part 28. For example, the discharge part 27 and the shoulder part 28 are integrally formed of a single material such as brass or copper alloy. The discharge part 27 protrudes more in the direction toward the anode electrode 20b than the shoulder part 28. The shoulder part 28 is connected to the side surface of the discharge part 27.

[0078] As Figure 4 shown, the discharge part 27 extends in the Z direction, and its surface includes a discharge surface 27a and an end surface 27b. The discharge surface 27a extends in the Z direction. The end surface 27b is provided at the end of the discharge part 27 in the Z direction. When viewed from the X direction, the discharge surface 27a is linear and the end surface 27b is curved. The curve forming the end surface 27b is a smooth curve for suppressing electric field concentration, for example, a curve derived from a theoretical formula such as Ernst.

[0079] The structure of the anode electrode 20b is the same as that of the cathode electrode 20a. Specifically, the anode electrode 20b has a shape that is symmetric to the cathode electrode 20a with respect to the XZ plane. Hereinafter, the length of each electrode in the Z direction will be referred to as the "electrode length". In addition, the length of the discharge surface 27a of each electrode in the Z direction will be referred to as the "discharge length".

[0080] 1.2 Operation

[0081] Next, the operation of the gas laser device 2 of the comparative example will be described. First, the processor 14 drives the motor 23a to rotate the fan 23. As a result, inside the laser chamber 10, the laser gas circulates in the order of the fan 23, the discharge space 29, and the heat exchanger 24. At this time, the shoulder 28 rectifies the laser gas to suppress the loss of the flow rate.

[0082] The processor 14 receives the oscillation trigger signal transmitted from the exposure device controller 110. In addition, the oscillation trigger signal is a signal indicating that the gas laser device 2 outputs pulsed laser PL of one pulse amount. The energy of the pulsed laser PL of this one pulse amount will be referred to as the "pulse energy".

[0083] The processor 14 sets a prescribed charging voltage for the charger 11 and causes the switch SW of the PPM 12 to operate in synchronization with the oscillation trigger signal.

[0084] When the switch SW of the PPM 12 changes from off to on, a voltage is applied between the preionization inner electrode 19c and the preionization outer electrode 19a of the preionization electrode 19 and between the cathode electrode 20a and the anode electrode 20b. As a result, a corona discharge is generated in the preionization electrode 19, and UV (Ultraviolet) light is generated. By irradiating the laser gas in the discharge space 29 with the UV light, the laser gas is preionized.

[0085] After that, when the voltage between the cathode electrode 20a and the anode electrode 20b reaches the breakdown voltage, a main discharge is generated in the discharge space 29. If the discharge direction of the main discharge is set as the direction of electron flow, the discharge direction is from the cathode electrode 20a toward the anode electrode 20b. When the main discharge is generated, the laser gas in the discharge space 29 is excited and emits light.

[0086] By circulating the laser gas in the laser chamber 10, the discharge products generated in the discharge space 29 move to the downstream side, and fresh laser gas is supplied to the discharge space 29 during the next discharge. In addition, when the laser gas passes through the heat exchanger 24, the heat generated by the discharge is removed, thereby suppressing the temperature rise of the laser gas.

[0087] The light emitted from the laser gas is reflected by the narrowbanding module 15 and the output coupling mirror 16 and reciprocates within the laser resonator, thereby performing laser oscillation. The light narrowbanded by the narrowbanding module 15 is output as pulsed laser PL from the output coupling mirror 16. The pulsed laser PL output from the output coupling mirror 16 is incident on the exposure apparatus 100.

[0088] In addition, the gas laser device 2 is not necessarily limited to a narrowbanding laser device, and may also be a laser device that outputs natural oscillation light. For example, a high reflection mirror may be arranged instead of the narrowbanding module 15.

[0089] In addition, in Figure 1 and Figure 2 As an example of the gas laser device 2, an excimer laser device is illustrated, but the gas laser device 2 may also be an F2 laser device or the like that uses a laser gas containing fluorine gas and a buffer gas.

[0090] 1.3 Problems

[0091] In the gas laser device 2, in order to achieve the required pulse energy, it is necessary to appropriately set the input energy density per unit volume in the discharge space 29, that is, the input energy density. In order to appropriately set the input energy density, it is necessary to appropriately set the volume of the discharge space 29 calculated based on the interval between the cathode electrode 20a and the anode electrode 20b, the discharge width, and the discharge length.

[0092] In addition, in the gas laser device 2, it is required to output pulsed laser PL having a large pulse energy. In order to achieve such a large pulse energy, it is necessary to increase the input energy while appropriately setting the input energy density. Therefore, it is considered to increase the discharge length.

[0093] However, as Figure 4 shown, the cathode electrode 20a and the anode electrode 20b have end faces 27b that contribute little to the discharge. Therefore, if the discharge length is increased for large pulse energy, the electrode length becomes very long. In this way, if the electrode length becomes long, it is necessary to elongate the laser chamber 10, but the elongation requires a huge cost, so it becomes an obstacle to large pulse energy.

[0094] Moreover, according to the structure of the laser chamber 10, the end face 27b disturbs the flow distribution of the laser gas, and thus sometimes the flow velocity of the laser gas decreases.

[0095] Therefore, it is required to achieve large pulse energy while suppressing the elongation of the laser chamber 10 and the decrease in the flow velocity of the laser gas.

[0096] 2. First Embodiment

[0097] 2.1 Structure

[0098] The gas laser device 2 of the first embodiment of the present disclosure has the same structure as that of the gas laser device 2 of the comparative example except for the structure inside the laser chamber 10.

[0099] Figure 5 FIG. 4 is a cross-sectional view of the laser chamber 10 of the first embodiment as viewed from the Z direction. The difference between the laser chamber 10 of the present embodiment and the laser chamber 10 of the comparative example is only that the main electrode 30 is provided instead of the main electrode 20 of the comparative example.

[0100] The main electrode 30 is composed of a cathode electrode 30a and an anode electrode 30b. The cathode electrode 30a and the anode electrode 30b are the same as the cathode electrode 20a and the anode electrode 20b of the comparative example except for the shape. In addition, the cathode electrode 30a and the anode electrode 30b are an example of "a pair of electrodes" of the technology of the present disclosure.

[0101] Figures 6 - 9 FIG. 11 shows the structure of the cathode electrode 30a of the first embodiment. Figure 6 FIG. 13 is a schematic perspective view schematically showing the cathode electrode 30a. Figure 7 FIG. 15 is a top view schematically showing the end portion of the cathode electrode 30a. Figure 8 FIG. 17 is a cross-sectional view showing a cross-section along the Figure 7 A-A line. Figure 9 FIG. 21 is a cross-sectional view showing a cross-section along the Figure 7 B-B line.

[0102] As Figure 6 shown, the cathode electrode 30a extends in the Z direction. The cathode electrode 30a includes a discharge portion 31 and a shoulder portion 32. In the present embodiment, the discharge portion 31 and the shoulder portion 32 are integrally formed of a single material such as brass or copper alloy. The discharge portion 31 protrudes more in the direction toward the anode electrode 30b than the shoulder portion 32. The shoulder portion 32 is provided so as to surround the side surface of the discharge portion 31. The shoulder portion 32 rectifies the laser gas to suppress the loss of the flow rate.

[0103] Alternatively, the discharge portion 31 and the shoulder portion 32 may be formed of different components. In this case, the discharge portion 31 and the shoulder portion 32 may be formed of the same material or different materials.

[0104] As Figures 6 - 9 shown, the discharge portion 31 extends in the Z direction, and its surface includes a discharge surface 31a and an end surface 31b. The discharge surface 31a extends in the Z direction. The end surface 31b is provided at the end portion of the discharge portion 31 in the Z direction. Specifically, the end surfaces 31b are provided at both end portions of the discharge portion 31. The two end surfaces 31b are symmetric with respect to the XY plane, and therefore only one end surface 31b will be described below.

[0105] In the present embodiment, the end face 31b is a part of a rotating ellipsoidal surface centered on the rotation axis C. The rotation axis C is the intersection line of the first cross-section 33a and the second cross-section 33b. The first cross-section 33a is a cross-section obtained by cutting the end of the discharge part 31 with the XY plane, and the second cross-section 33b is a cross-section obtained by cutting with the YZ plane in such a way as to pass through the center in the X direction of the discharge part 31. That is, the rotation axis C is located at the position of the center in the width direction of the end of the discharge surface 31a. The XY plane is an example of the "plane parallel to the first direction and the third direction" of the technology of the present disclosure. The YZ plane is an example of the "plane parallel to the first direction and the second direction" of the technology of the present disclosure.

[0106] The end face 31b is a part of a rotating ellipsoidal surface, i.e., a flat ellipsoidal surface, with the minor axis as the rotation axis C. As Figure 10 shown, when the major axis radius of the rotating ellipsoidal surface constituting the end face 31b is set as L1 and the minor axis radius is set as L2, it is preferable to satisfy the relationship of 2 ≤ L1 / L2 ≤ 10. Particularly preferably, L1 / L2 = 5.

[0107] In addition, for example, the end face 31b is one of the four divided surfaces obtained by cutting the rotating ellipsoidal surface with the XY plane containing the minor axis and the XZ plane containing the major axis. Therefore, as Figure 7 shown, the planar shape of the end face 31b observed from the Y direction is a semi-circular shape.

[0108] At the end of the discharge part 31, the discharge part 31 and the shoulder part 32 are symmetric with respect to the second cross-section 33b. Therefore, Figure 8 the cross-sectional shape of the end in the first cross-section 33a shown is the same as the cross-sectional shape of the end in the second cross-section 33b shown. Here, the cross-sectional shape refers to the shapes of the discharge part 31 and the shoulder part 32 divided by the rotation axis C in Figure 9 and Figure 8 and Figure 9 . In addition, the same also includes shapes that are line-symmetric and become the same through inversion operations.

[0109] In the first cross-section 33a and the second cross-section 33b, the surface of the shoulder part 32 includes a curved part 32a. The curved part 32a is connected to the end face 31b via a straight part 32b. The curved part 32a is a part of a spherical surface centered on a point on the rotation axis C. For example, the curved part 32a is a part of a spherical surface with a radius of R10. The straight part 32b forms a conical surface.

[0110] In addition, the cut shape in the width direction at any position of the discharge surface 31a is an elliptical arc that is the same as the cross-sectional shape of the end face 31b in the first cross-section 33a.

[0111] The structure of the anode electrode 30b is the same as that of the cathode electrode 30a. Specifically, the anode electrode 30b has a shape that is symmetric with respect to the XZ plane with the cathode electrode 30a.

[0112] 2.2 Operation

[0113] The operation of the gas laser device 2 of the present embodiment is the same as that of the comparative example except for the different functions of the main electrodes 30.

[0114] 2.3 Function and Effect

[0115] Figure 11 is a side view of the cathode electrode 30a of the first embodiment as viewed from the X direction. In Figure 11 for comparison, the cathode electrode 20a of the comparative example is shown.

[0116] In the cathode electrode 30a and the anode electrode 30b of the present embodiment, the end face 31b is a part of a rotating ellipsoid surface, and thus the length of the end face 31b in the Z direction is short. Therefore, the discharge length can be increased without increasing the electrode length. As a result, high pulse energy can be achieved without making the laser chamber 10 long.

[0117] In addition, shoulders 32 are provided at the Z-direction ends of the cathode electrode 30a and the anode electrode 30b in the present embodiment. Therefore, the laser gas can be rectified at the ends to suppress the loss of the flow rate.

[0118] Therefore, according to the present embodiment, high pulse energy can be achieved while suppressing the elongation of the laser chamber 10 and the decrease in the flow rate of the laser gas.

[0119] In addition, as in the above embodiment, it is preferable that the cathode electrode 30a and the anode electrode 30b have the same structure, but the structure described in the above embodiment may be applied to only one of the cathode electrode 30a and the anode electrode 30b. For example, the cathode electrode 30a may have the structure described in the above embodiment, and the anode electrode 30b may have the same structure as the anode electrode 20b of the comparative example.

[0120] 3. Second Embodiment

[0121] 3.1 Structure

[0122] The gas laser device 2 of the second embodiment of the present disclosure will be described. In addition, the same reference numerals are given to the structures that are the same as those described above, and the repeated description is omitted except in special cases. The gas laser device 2 of the present embodiment has the same structure as the gas laser device 2 of the first embodiment except for a part of the structures of the cathode electrode 30a and the anode electrode 30b.

[0123] Figure 12 and Figure 13 shows the structure of the cathode electrode 30a of the second embodiment. Figure 12 is a cross-sectional view of the cathode electrode 30a observed from the Z direction. Figure 13 is a cross-sectional view of the cathode electrode 30a observed from the X direction.

[0124] In the present embodiment, the discharge portion 31 and the shoulder portion 32 are formed of different components. In the present embodiment, the discharge portion 31 is formed of a metal material such as brass or copper alloy, and the shoulder portion 32 is formed of an insulating material. For example, the shoulder portion 32 is formed of a ceramic such as alumina or zirconia.

[0125] The other structures of the cathode electrode 30a of the present embodiment are the same as those of the cathode electrode 30a of the first embodiment. The structure of the anode electrode 30b is the same as that of the cathode electrode 30a. In addition, the structure of the anode electrode 30b of the present embodiment may also be the same as the structure of the anode electrode 20b of the comparative example or the anode electrode 30b of the first embodiment.

[0126] 3.2 Operation

[0127] The operation of the gas laser device 2 of the present embodiment is the same as that of the comparative example except for the different functions of the main electrodes 30.

[0128] 3.3 Function and Effect

[0129] In the present embodiment, since the shoulder portion 32 formed of an insulating material surrounds the side surface of the discharge portion 31, in addition to the effects of the first embodiment, an effect of being able to suppress unexpected discharges other than the discharge portion 31 can be obtained.

[0130] 4. Third Embodiment

[0131] 4.1 Structure

[0132] The gas laser device 2 of the third embodiment of the present disclosure will be described. In addition, the same reference numerals are given to the structures that are the same as those described above, and redundant descriptions are omitted except in special cases. The gas laser device 2 of the present embodiment has the same structure as the gas laser device 2 of the first embodiment except for a part of the structures of the cathode electrode 30a and the anode electrode 30b.

[0133] Figure 14 and Figure 15 shows the structure of the cathode electrode 30a of the third embodiment. Figure 14 is a side view of the cathode electrode 30a observed from the Z direction. Figure 15 is a side view of the cathode electrode 30a observed from the X direction.

[0134] In the present embodiment, an insulating film 40 is formed on the surface of the shoulder 32 of the cathode electrode 30a. For example, the insulating film 40 is formed so as to cover the curved portion 32a. For example, the insulating film 40 is an alumina sprayed coating film formed by spraying alumina (Al2O3) by a plasma spraying method. The thickness of the insulating film 40 is preferably 200 μm or less.

[0135] The other structure of the cathode electrode 30a of the present embodiment is the same as that of the cathode electrode 30a of the first embodiment. The structure of the anode electrode 30b is the same as that of the cathode electrode 30a. In addition, the structure of the anode electrode 30b of the present embodiment may also be the same as the anode electrode 20b of the comparative example, or the anode electrode 30b of the first embodiment or the second embodiment.

[0136] 4.2 Operation

[0137] The operation of the gas laser device 2 of the present embodiment is the same as that of the comparative example except that the function of the main electrode 30 is different.

[0138] 4.3 Function and Effect

[0139] In the present embodiment, since the insulating film 40 is formed on the surface of the shoulder 32, in addition to the effects of the first embodiment, it is also possible to obtain the effect of suppressing unexpected discharges other than the discharge portion 31.

[0140] 5. Fourth Embodiment

[0141] 5.1 Structure

[0142] The gas laser device 2 of the fourth embodiment of the present disclosure will be described. In addition, the same reference numerals are given to the structures that are the same as those described above, and repeated descriptions are omitted unless otherwise specified. The gas laser device 2 of the present embodiment has the same structure as the gas laser device 2 of the first embodiment except for a part of the structure of the anode electrode 30b.

[0143] Figure 16 And Figure 17 shows the structure of the anode electrode 30b of the fourth embodiment. Figure 16 is a side view of the anode electrode 30b observed from the Z direction. Figure 17 is a side view of the anode electrode 30b observed from the X direction.

[0144] The anode electrode 30b has the same structure as the cathode electrode 30a, including a discharge portion 31 extending in the Z direction and a shoulder portion 32 provided so as to surround the side surface of the discharge portion 31. The surface of the discharge portion 31 includes a discharge surface 31a extending in the Z direction and end surfaces 31b provided at both end portions in the extending direction of the discharge portion 31. The end surface 31b is a part of a rotational ellipsoidal surface. Other structures of the anode electrode 30b in the present embodiment are the same as those of any one of the cathode electrodes 30a in the first to third embodiments except for the arrangement direction.

[0145] In the present embodiment, an alumina spray coating film 50 in which metals such as copper are dispersed is formed on the discharge surface 31a and the end surface 31b of the anode electrode 30b. The alumina spray coating film 50 is formed by a plasma spraying method. Preferably, the thickness of the alumina spray coating film 50 is 200 μm or less.

[0146] The cathode electrode 30a in the present embodiment has the same structure as any one of the cathode electrodes 30a in the first to third embodiments.

[0147] 5.2 Operation

[0148] The operation of the gas laser device 2 in the present embodiment is the same as that of the comparative example except for the function of the main electrode 30.

[0149] 5.3 Function and Effect

[0150] In the present embodiment, since the alumina spray coating film 50 is formed on the discharge surface 31a and the end surface 31b of the anode electrode 30b, in addition to any effects in the first to third embodiments, an effect of suppressing deterioration of the anode electrode 30b caused by the impact of discharge can be obtained. As a result, the main electrode 30 has a long life. In addition, this effect is known from Japanese Patent No. 4059758 and Japanese Patent No. 4367886.

[0151] 6. Manufacturing Method of Electronic Device

[0152] Figure 18 A structural example of the exposure apparatus 100 is schematically shown. The exposure apparatus 100 includes an illumination optical system 104 and a projection optical system 106. The illumination optical system 104 illuminates, for example, a mask pattern of an unillustrated mask disposed on the mask stage RT by using pulsed laser light PL incident from the gas laser device 2. The projection optical system 106 reduces and projects the pulsed laser light PL transmitted through the mask and images it on an unillustrated workpiece disposed on the workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a photoresist.

[0153] The exposure apparatus 100 exposes the pulsed laser PL reflecting the reticle pattern onto the workpiece by causing the reticle stage RT and the workpiece stage WT to move in parallel synchronously. After transferring the reticle pattern onto the semiconductor wafer through the above exposure step, semiconductor devices can be manufactured through multiple processes. The semiconductor device is an example of the "electronic device" in the present disclosure.

[0154] In addition, the gas laser device 2 is not limited to the manufacture of electronic devices and can also be used for laser processing such as drilling.

[0155] The above description is illustrative rather than restrictive. Therefore, it is obvious to those skilled in the art that various modifications can be made to the embodiments of the present disclosure without departing from the appended claims.

[0156] The terms used in this specification and the appended claims should be construed as "non-restrictive" terms. For example, the term "comprising" or "including" should be construed as "not limited to being described as including". The term "having" should be construed as "not limited to being described as having". In addition, the modifier "a" described in this specification and the appended claims should be construed as "at least one" or "one or more". Further, the term "at least one of A, B, and C" should be construed as "A", "B", "C", "A + B", "A + C", "B + C", or "A + B + C", and should also be construed as including combinations thereof with elements other than "A", "B", and "C".

Claims

1. A laser chamber, which houses a pair of electrodes arranged to face each other in a first direction and is configured to allow the introduction of laser gas, wherein: At least one of the pair of electrodes includes: a discharge portion extending in a second direction orthogonal to the first direction; and a shoulder portion arranged to surround a side surface of the discharge portion, The surface of the discharge portion includes: a discharge surface extending along the second direction; and an end surface disposed at an end of the discharge portion in the second direction. The end surface is a part of a rotational ellipsoid.

2. The laser chamber according to claim 1, wherein: The discharge portion protrudes further in the first direction than the shoulder portion.

3. The laser chamber according to claim 1, wherein: When the direction orthogonal to the first direction and the second direction is set as the third direction, the rotation axis of the rotating ellipsoid is the intersection line of the first section and the second section, the first section is the section obtained by cutting the end portion using a plane parallel to the first direction and the third direction, and the second section is the section obtained by cutting the end portion using a plane parallel to the first direction and the second direction.

4. The laser chamber according to claim 3, wherein: The cross-sectional shapes of the end portions in the first cross section and the second cross section are the same.

5. The laser chamber according to claim 4, wherein: The rotation ellipsoid is a flat ellipsoid with the minor axis as the rotation axis.

6. The laser chamber according to claim 5, wherein: When the major axis radius of the rotation ellipsoid is L1 and the minor axis radius of the rotation ellipsoid is L2, the relationship of 2≤L1 / L2≤10 is satisfied.

7. The laser chamber according to claim 1, wherein: The discharge portion and the shoulder portion are integrally formed of a single material.

8. The laser chamber according to claim 1, wherein: The discharge portion and the shoulder portion are formed of different components.

9. The laser chamber according to claim 8, wherein: The shoulder is formed of an insulating material.

10. The laser chamber according to claim 9, wherein: The insulating material is aluminum oxide or zirconium oxide.

11. The laser chamber according to claim 1, wherein: An insulating film is formed on a surface of the shoulder portion.

12. The laser chamber according to claim 11, wherein: The insulating film is an aluminum oxide spray coating.

13. The laser chamber according to claim 12, wherein: The insulating film has a thickness of 200 μm or less.

14. The laser chamber of claim 1, wherein: One of the pair of electrodes is an anode electrode having an aluminum oxide sprayed film in which a metal is dispersed formed on the discharge surface and the end surface.

15. The laser chamber of claim 14, wherein: The aluminum oxide sprayed coating has a thickness of 200 μm or less.

16. The laser chamber of claim 1, wherein: The shoulder rectifies the laser gas.

17. A gas laser device comprising: a laser chamber that accommodates a pair of electrodes disposed to face each other in a first direction and is configured to allow introduction of laser gas; a power supply device connected to the pair of electrodes; as well as A processor controls the power supply device to discharge the pair of electrodes, wherein: At least one of the pair of electrodes includes: a discharge portion extending in a second direction orthogonal to the first direction; and a shoulder portion arranged to surround a side surface of the discharge portion, The surface of the discharge portion includes: a discharge surface extending along the second direction; and an end surface disposed at an end of the discharge portion in the second direction. The end surface is a part of a rotational ellipsoid.

18. A method for manufacturing an electronic device, wherein: The manufacturing method of the electronic device comprises the following steps: introducing laser gas into a laser chamber of a gas laser device; generating laser light by the gas laser device; outputting the laser light to an exposure device; and exposing the laser on a photosensitive substrate in the exposure device to manufacture an electronic device, The gas laser device comprises: The laser chamber accommodates a pair of electrodes arranged to face each other in a first direction and is configured to be able to introduce the laser gas; a power supply device connected to the pair of electrodes; as well as a processor that controls the power supply device to discharge the pair of electrodes, At least one of the pair of electrodes includes: a discharge portion extending in a second direction orthogonal to the first direction; and a shoulder portion arranged to surround a side surface of the discharge portion, The surface of the discharge portion includes: a discharge surface extending along the second direction; and an end surface disposed at an end of the discharge portion in the second direction. The end surface is a part of a rotational ellipsoid.

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