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

Abstract

To achieve large pulse energy, while preventing an increase in the length of a laser chamber and a reduction in the flow rate of laser gas.SOLUTION: A laser chamber accommodates a pair of electrodes arranged to face each other in a first direction, and can introduce laser gas. At least one of the pair of electrodes includes a discharge part extending in a second direction orthogonal to the first direction, and a shoulder part arranged to surround a side face of the discharge part. A surface of the discharge part includes a discharge surface extending in the second direction, and an end face provided at an end in the second direction of the discharge part. The end face is part of a rotating elliptic surface.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure 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 apparatuses, as semiconductor integrated circuits have been miniaturized and highly integrated, an improvement in resolution has been demanded. For this reason, the wavelength of light emitted from an exposure light source has been shortened. For example, as a gas laser device for exposure, a KrF excimer laser device that outputs laser light with a wavelength of about 248 nm and an ArF excimer laser device that outputs laser light with a wavelength of about 193 nm are used.

[0003] The spectral linewidth of the spontaneous emission light of a KrF excimer laser device and an ArF excimer laser device is as wide as 350 to 400 pm. Therefore, when a projection lens is configured with a material that transmits ultraviolet light such as KrF and ArF laser light, chromatic aberration may occur. As a result, the resolution may decrease. Therefore, it is necessary to narrow the spectral linewidth of the laser light output from the gas laser device to such an extent that chromatic aberration can be ignored. For this reason, a narrowbanding module (Line Narrowing Module: LNM) including a narrowbanding element (etalon, grating, etc.) may be provided in the laser resonator of the gas laser device to narrow the spectral linewidth. Hereinafter, a gas laser device in which the spectral linewidth is narrowed is referred to as a narrowbanded gas laser device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

[0005] A laser chamber according to one aspect of the present disclosure is a laser chamber that houses a pair of electrodes arranged to face each other in a first direction and is configured to introduce a laser gas. 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 in the second direction and an end surface provided at an end of the discharge portion in the second direction. The end surface is a part of a rotational ellipsoidal surface.

[0006] A gas laser device according to one 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 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 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 in the second direction and an end surface provided at an end of the discharge portion in the second direction. The end surface is a part of a rotational ellipsoidal surface.

[0007] A method for manufacturing an electronic device according to one 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 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 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 in the second direction and an end surface provided at an end of the discharge portion in the second direction. The end surface is a part of a rotational ellipsoidal surface. The method includes introducing a laser gas into the laser chamber of the gas laser device, generating laser light by the gas laser device, outputting the laser light to an exposure device, and exposing a photosensitive substrate to the laser light in the exposure device to manufacture an electronic device.

Brief Description of the Drawings

[0008] Some embodiments of the present disclosure will be described below by way of example only with reference to the accompanying drawings.

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[0009] <Content> 1. Comparative Example 1.1 Configuration 1.2 Operation 1.3 Problem 2. First Embodiment 2.1 Configuration 2.2 Operation 2.3 Function and Effect 3. Second Embodiment 3.1 Configuration 3.2 Operation 3.3 Function and Effect 4. Third Embodiment 4.1 Configuration 4.2 Operation 4.3 Function and Effect 5. Fourth Embodiment 5.1 Configuration 5.2 Operation 5.3 Function and Effect 6. Method for Manufacturing an Electronic Device

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show some examples of the present disclosure and do not limit the content of the present disclosure. Further, not all of the configurations and operations described in the embodiments are essential as the configurations and operations of the present disclosure. Note that the same reference numerals are assigned to the same components, and redundant descriptions are omitted.

[0011] 1. Comparative Example First, the comparative example of the present disclosure will be described. The comparative example of the present disclosure is a form recognized by the applicant as being known only to the applicant and is not a publicly known example recognized by the applicant.

[0012] 1.1 Configuration The configuration of the gas laser device 2 according to the comparative example will be described with reference to FIGS. 1 and 2. FIG. 1 schematically shows the configuration of the gas laser device 2. FIG. 2 is a cross-sectional view of the laser chamber 10 shown in FIG. 1 as viewed from the Z direction. The gas laser device 2 is a discharge-excited type gas laser device that excites a laser gas by discharge, and is, for example, an excimer laser device.

[0013] In FIG. 1, the traveling direction of the pulsed laser light PL output from the gas laser device 2 is defined as the Z direction. The discharge direction described later is defined as the Y direction. The Y direction is perpendicular to the Z direction. Also, the direction perpendicular to the Y direction and the Z direction is defined as the X direction. Note that the Y direction corresponds to the "first direction" according to the technology of the present disclosure. The Z direction corresponds to the "second direction" according to the technology of the present disclosure. The X direction corresponds to the "third direction" according to the technology of the present disclosure. Also, the pulsed laser light PL is an example of the "laser light" according to the technology of the present disclosure.

[0014] In FIG. 1, 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 narrowband module 15 and an output coupling mirror 16.

[0015] The laser chamber 10 is, for example, a metal container formed of an aluminum metal plated with nickel on its surface. As shown in FIGS. 1 and 2, inside the laser chamber 10, a main electrode 20, a ground plate 21, wiring 22, a fan 23, a heat exchanger 24, and a preionization electrode 19 are provided. The preionization electrode 19 includes a preionization outer electrode 19a, a dielectric pipe 19b, and a preionization inner electrode 19c.

[0016] A laser gas containing fluorine is introduced into the laser chamber 10 as a laser medium. The laser gas includes, for example, noble gases such as argon, krypton, and xenon, buffer gases such as neon and helium, and halogen gases such as fluorine and chlorine.

[0017] Further, an opening is formed in the laser chamber 10. An electric insulation plate 26 in which a feed-through 25 is embedded is attached to the laser chamber 10 via an O-ring (not shown) so as to close the opening. A PPM 12 is disposed on the electric insulation plate 26. The laser chamber 10 is grounded.

[0018] The PPM 12 includes a charging capacitor (not shown) and is connected to the main electrode 20 via the feed-through 25. The PPM 12 includes a switch SW for discharging the main electrode 20. A charger 11 is connected to the charging capacitor of the PPM 12. Hereinafter, the discharge occurring at the main electrode 20 is referred to as the main discharge. The PPM 12 is an example of the "power supply device" according to the technology of the present disclosure.

[0019] 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 referred to as a discharge space 29. The cathode electrode 20a is supported by the electric insulation plate 26 on the surface opposite to the discharge space 29 and is connected to the feed-through 25. The anode electrode 20b is supported by the ground plate 21 on the surface opposite to the discharge space 29.

[0020] 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.

[0021] The fan 23 is a cross-flow fan for circulating the laser gas in 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.

[0022] 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 a valve and a flow control valve and is connected to a gas cylinder containing the laser gas. The laser gas exhaust device includes a valve and an exhaust pump.

[0023] Windows 10a and 10b for emitting the light generated in 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.

[0024] The narrowbanding module 15 includes a prism 15a and a grating 15b. The prism 15a transmits the light emitted from the laser chamber 10 through the window 10a while expanding the beam width and transmits it to the grating 15b side.

[0025] The grating 15b is arranged in a retroreflective arrangement in which the incident angle and the diffraction angle are the same angle. The grating 15b is a wavelength selection element that selectively extracts light near a specific wavelength according to the diffraction angle. The spectral width of the light returning from the grating 15b to the laser chamber 10 through the prism 15a is narrowed.

[0026] The output coupling mirror 16 transmits a part of the light emitted from the laser chamber 10 through the window 10b and reflects the other part and returns it to the laser chamber 10. A partial reflection film is coated on the surface of the output coupling mirror 16.

[0027] 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 light PL through the output coupling mirror 16.

[0028] The pressure sensor 17 detects the gas pressure in the laser chamber 10 and outputs the detected value to the processor 14. The processor 14 determines the gas pressure of the laser gas in the laser chamber 10 based on the detected value of the gas pressure and the charging voltage of the charger 11.

[0029] 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 from the electrical energy stored in the charging capacitor and applies it to the main electrode 20.

[0030] 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 in which a control program is stored and an arithmetic device such as a CPU (Central Processing Unit) that executes the control program. For example, the processor 14 comprehensively controls the operations of the components of the gas laser device 2 based on various signals transmitted from the exposure device controller 110, the detected value of the gas pressure, and the like.

[0031] The configuration of the cathode electrode 20a according to the comparative example will be described with reference to FIGS. 3 and 4. FIG. 3 is a cross-sectional view of the cathode electrode 20a according to the comparative example as viewed from the Z direction. FIG. 4 is a side view of the cathode electrode 20a according to the comparative example as viewed from the X direction.

[0032] As shown in FIG. 3, the cathode electrode 20a includes a discharge portion 27 and a shoulder portion 28. For example, the discharge portion 27 and the shoulder portion 28 are integrally formed of a single material such as brass or a copper alloy. The discharge portion 27 protrudes in the direction toward the anode electrode 20b more than the shoulder portion 28. The shoulder portion 28 is connected to the side surface of the discharge portion 27.

[0033] As shown in FIG. 4, 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 Z-direction end of the discharge part 27. When viewed from the X direction, the discharge surface 27a is linear, and the end surface 27b is curved. The curve constituting the end surface 27b is a smooth curve for suppressing electric field concentration, and is, for example, a curve derived from a theoretical formula such as Ernst.

[0034] The configuration of the anode electrode 20b is the same as that of the cathode electrode 20a. Specifically, the anode electrode 20b has a shape symmetric to the cathode electrode 20a with respect to the XZ plane. Hereinafter, the length of each electrode in the Z direction is referred to as "electrode length". Also, the length of the discharge surface 27a of each electrode in the Z direction is referred to as "discharge length".

[0035] 1.2 Operation Next, the operation of the gas laser device 2 according to the comparative example will be described. First, the processor 14 drives the motor 23a to rotate the fan 23. Thereby, in 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 part 28 rectifies the laser gas to suppress the loss of the flow velocity.

[0036] The processor 14 receives an oscillation trigger signal transmitted from the exposure apparatus controller 110. The oscillation trigger signal is a signal instructing the gas laser device 2 to output pulsed laser light PL for one pulse. The energy of the pulsed laser light PL for one pulse is referred to as "pulse energy".

[0037] The processor 14 sets a predetermined charging voltage in the charger 11 and operates the switch SW of the PPM 12 in synchronization with the oscillation trigger signal.

[0038] When the switch SW of PPM12 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 occurs at the preionization electrode 19, generating UV (Ultraviolet) light. The laser gas in the discharge space 29 is irradiated with the UV light, thereby preionizing the laser gas.

[0039] After that, when the voltage between the cathode electrode 20a and the anode electrode 20b reaches the breakdown voltage, a main discharge occurs in the discharge space 29. Assuming the discharge direction of the main discharge is the direction in which electrons flow, the discharge direction is from the cathode electrode 20a toward the anode electrode 20b. When the main discharge occurs, the laser gas in the discharge space 29 is excited and emits light.

[0040] As the laser gas circulates within 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. Also, when the laser gas passes through the heat exchanger 24, the heat associated with the discharge is removed, suppressing the temperature rise of the laser gas.

[0041] 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 causing laser oscillation. The light narrowbanded by the narrowbanding module 15 is output from the output coupling mirror 16 as pulsed laser light PL. The pulsed laser light PL output from the output coupling mirror 16 is incident on the exposure apparatus 100.

[0042] Note that the gas laser device 2 is not necessarily limited to a narrowbanding laser device and may be a laser device that outputs spontaneously emitted light. For example, a high-reflection mirror may be arranged instead of the narrowbanding module 15.

[0043] In FIGS. 1 and 2, an excimer laser device is illustrated as the gas laser device 2. However, the gas laser device 2 may be an F2 laser device or the like that uses a laser gas containing fluorine gas and buffer gas.

[0044] 1.3 Problems In the gas laser device 2, in order to achieve the required pulse energy, it is necessary to appropriately set the input energy density, which is the input energy per unit volume in the discharge space 29. To appropriately set the input energy density, it is necessary to appropriately set the volume of the discharge space 29 calculated from the distance between the cathode electrode 20a and the anode electrode 20b, the discharge width, and the discharge length.

[0045] In addition, in the gas laser device 2, it is required to output a pulsed laser beam 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. For this purpose, it is conceivable to increase the discharge length.

[0046] However, as shown in FIG. 4, since the cathode electrode 20a and the anode electrode 20b have end faces 27b that contribute little to the discharge, if the discharge length is increased to increase the pulse energy, the electrode length becomes very long. When the electrode length becomes long in this way, it is necessary to lengthen the laser chamber 10, but lengthening requires a great deal of cost, which is an obstacle to increasing the pulse energy.

[0047] In addition, depending on the structure of the laser chamber 10, the end face 27b may disturb the distribution of the flow of the laser gas, resulting in a decrease in the flow velocity of the laser gas.

[0048] Therefore, it is required to realize a large pulse energy while suppressing the lengthening of the laser chamber 10 and the decrease in the flow velocity of the laser gas.

[0049] 2. First Embodiment 2.1 Configuration The gas laser device 2 according to the first embodiment of the present disclosure has the same configuration as the gas laser device 2 according to the comparative example, except that the configuration inside the laser chamber 10 is different.

[0050] FIG. 5 is a cross-sectional view of the laser chamber 10 according to the first embodiment as viewed from the Z direction. The laser chamber 10 according to the present embodiment is different from the laser chamber 10 according to the comparative example only in that the main electrode 30 is provided instead of the main electrode 20 according to the comparative example.

[0051] 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 according to the comparative example, except that their shapes are different. Note that the cathode electrode 30a and the anode electrode 30b are an example of the "pair of electrodes" according to the technology of the present disclosure.

[0052] FIGS. 6 to 9 show the configuration of the cathode electrode 30a according to the first embodiment. FIG. 6 is a perspective view schematically showing the cathode electrode 30a. FIG. 7 is a plan view schematically showing the end portion of the cathode electrode 30a. FIG. 8 is a cross-sectional view showing a cross-section along line A-A in FIG. 7. FIG. 9 is a cross-sectional view showing a cross-section along line B-B in FIG. 7.

[0053] As shown in FIG. 6, 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 a copper alloy. The discharge portion 31 protrudes in the direction toward the anode electrode 30b more 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 and suppresses the loss of the flow velocity.

[0054] Note that the discharge portion 31 and the shoulder portion 32 may be composed 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.

[0055] As shown in FIGS. 6 to 9, the discharge part 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 of the discharge part 31 in the Z direction. Specifically, the end surface 31b is provided at both ends of the discharge part 31 respectively. Since the two end surfaces 31b are symmetric in shape with respect to the XY plane, hereinafter, only one of the end surfaces 31b will be described.

[0056] In the present embodiment, the end surface 31b is a part of an ellipsoidal surface of revolution centered on the rotation axis C. The rotation axis C is the intersection line of a first cross-section 33a obtained by cutting the end of the discharge part 31 in the XY plane and a second cross-section 33b obtained by cutting the discharge part 31 in the YZ plane so as to pass through the center in the X direction. That is, the rotation axis C is the end of the discharge surface 31a and is located at the center in the width direction. The XY plane is an example of the "plane parallel to the first direction and the third direction" according to the technology of the present disclosure. The YZ plane is an example of the "plane parallel to the first direction and the second direction" according to the technology of the present disclosure.

[0057] The end surface 31b is a part of a flattened ellipsoidal surface which is an ellipsoidal surface of revolution with the minor axis as the rotation axis C. As shown in FIG. 10, when the major axis radius of the ellipsoidal surface of revolution constituting the end surface 31b is L1 and the minor axis radius is L2, it is preferable to satisfy the relationship of 2 ≤ L1 / L2 ≤ 10. In particular, it is preferable that L1 / L2 = 5.

[0058] Also, for example, the end surface 31b is one of the four divided surfaces formed by cutting the ellipsoidal surface of revolution with the XY plane including the minor axis and the XZ plane including the major axis. Therefore, as shown in FIG. 7, the planar shape of the end surface 31b viewed from the Y direction is a semi-circular shape.

[0059] At the end of the discharge part 31, the discharge part 31 and the shoulder part 32 are plane-symmetric with respect to the second cross-section 33b. Therefore, the cross-sectional shape of the end in the first cross-section 33a shown in FIG. 8 is the same as the cross-sectional shape of the end in the second cross-section 33b shown in FIG. 9. Here, the cross-sectional shape refers to the shape of the discharge part 31 and the shoulder part 32 divided by the rotation axis C in FIGS. 8 and 9. Also, the same means line-symmetric and includes shapes that become the same by an inversion operation.

[0060] 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 one 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 constitutes a tapered surface.

[0061] Also, the cross-sectional shape in the width direction at any position of the discharge surface 31a is the same elliptical arc as the cross-sectional shape of the end face 31b in the first cross-section 33a.

[0062] The configuration 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 cathode electrode 30a about the XZ plane.

[0063] 2.2 Operation The operation of the gas laser device 2 according to the present embodiment is the same as that of the comparative example except that the action of the main electrode 30 is different.

[0064] 2.3 Action and Effect FIG. 11 is a side view of the cathode electrode 30a according to the first embodiment as viewed from the X direction. FIG. 11 shows the cathode electrode 20a according to the comparative example for comparison.

[0065] In the cathode electrode 30a and the anode electrode 30b according to the present embodiment, since the end face 31b is a part of an ellipsoidal surface, the length of the end face 31b in the Z direction is short, so the discharge length can be increased without increasing the electrode length. As a result, it is possible to realize an increase in pulse energy without increasing the length of the laser chamber 10.

[0066] Further, in the present embodiment, since the shoulders 32 are also provided at the Z-direction ends of the cathode electrode 30a and the anode electrode 30b, the laser gas can be rectified at the ends to suppress the loss of the flow velocity.

[0067] Therefore, according to the present embodiment, it is possible to realize an increase in pulse energy while suppressing an increase in the length of the laser chamber 10 and a decrease in the flow velocity of the laser gas.

[0068] Note that, as in the above embodiment, it is preferable that the cathode electrode 30a and the anode electrode 30b have the same configuration, but the configuration 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 configuration described in the above embodiment, and the anode electrode 30b may have the same configuration as the anode electrode 20b according to the comparative example.

[0069] 3. Second Embodiment 3.1 Configuration The gas laser device 2 according to the second embodiment of the present disclosure will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted unless otherwise specified. The gas laser device 2 according to the present embodiment has the same configuration as the gas laser device 2 according to the first embodiment, except that a part of the configurations of the cathode electrode 30a and the anode electrode 30b are different.

[0070] FIGS. 12 and 13 show the configuration of the cathode electrode 30a according to the second embodiment. FIG. 12 is a cross-sectional view of the cathode electrode 30a as viewed from the Z direction. FIG. 13 is a cross-sectional view of the cathode electrode 30a as viewed from the X direction.

[0071] In this embodiment, the discharge part 31 and the shoulder part 32 are composed of different components. In this embodiment, the discharge part 31 is formed of a metal material such as brass or copper alloy, and the shoulder part 32 is formed of an insulating material. For example, the shoulder part 32 is formed of a ceramic such as alumina or zirconium oxide.

[0072] Other configurations of the cathode electrode 30a according to this embodiment are the same as those of the cathode electrode 30a according to the first embodiment. The configuration of the anode electrode 30b is the same as that of the cathode electrode 30a. Note that the configuration of the anode electrode 30b according to this embodiment may be the same as the configuration of the anode electrode 20b according to the comparative example or the anode electrode 30b according to the first embodiment.

[0073] 3.2 Operation The operation of the gas laser device 2 according to this embodiment is the same as that of the comparative example, except that the action of the main electrode 30 is different.

[0074] 3.3 Action and Effect In this embodiment, since the shoulder part 32 formed of an insulating material surrounds the side surface of the discharge part 31, in addition to the effect according to the first embodiment, an effect that unexpected discharge outside the discharge part 31 can be suppressed is obtained.

[0075] 4. Third Embodiment 4.1 Configuration The gas laser device 2 according to the third embodiment of the present disclosure will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted unless otherwise specified. The gas laser device 2 according to this embodiment has the same configuration as the gas laser device 2 according to the first embodiment, except that a part of the configurations of the cathode electrode 30a and the anode electrode 30b are different.

[0076] FIG. 14 and FIG. 15 show the configuration of the cathode electrode 30a according to the third embodiment. FIG. 14 is a side view of the cathode electrode 30a viewed from the Z direction. FIG. 15 is a side view of the cathode electrode 30a viewed from the X direction.

[0077] In this embodiment, an insulating film 40 is formed on the surface of the shoulder portion 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 film formed by spraying alumina (Al2O3) by a plasma spraying method. The thickness of the insulating film 40 is preferably 200 μm or less.

[0078] Other configurations of the cathode electrode 30a according to this embodiment are the same as those of the cathode electrode 30a according to the first embodiment. The configuration of the anode electrode 30b is the same as that of the cathode electrode 30a. Note that the configuration of the anode electrode 30b according to this embodiment may be the same as the configuration of the anode electrode 20b according to the comparative example, or the anode electrode 30b according to the first embodiment or the second embodiment.

[0079] 4.2 Operation The operation of the gas laser device 2 according to this embodiment is the same as that of the comparative example except that the action of the main electrode 30 is different.

[0080] 4.3 Action and Effect In this embodiment, since the insulating film 40 is formed on the surface of the shoulder portion 32, in addition to the effect according to the first embodiment, an effect that unexpected discharge other than the discharge portion 31 can be suppressed is obtained.

[0081] 5. Fourth Embodiment 5.1 Configuration The gas laser device 2 according to the fourth embodiment of the present disclosure will be described. Note that the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted unless otherwise specifically described. The gas laser device 2 according to this embodiment has the same configuration as the gas laser device 2 according to the first embodiment except that a part of the configuration of the anode electrode 30b is different.

[0082] Figs. 16 and 17 show the configuration of the anode electrode 30b according to the fourth embodiment. Fig. 16 is a side view of the anode electrode 30b viewed from the Z direction. Fig. 17 is a side view of the anode electrode 30b viewed from the X direction.

[0083] The anode electrode 30b has the same configuration as the cathode electrode 30a, and includes 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 ends in the extending direction of the discharge portion 31. The end surface 31b is a part of a rotational ellipsoidal surface. Other configurations of the anode electrode 30b according to the present embodiment are the same as those of any of the cathode electrodes 30a according to the first to third embodiments, except that the arrangement direction is different.

[0084] In the present embodiment, an alumina sprayed coating 50 in which a metal such as copper is dispersed is formed on the discharge surface 31a and the end surfaces 31b of the anode electrode 30b. The alumina sprayed coating 50 is formed by a plasma spraying method. The thickness of the alumina sprayed coating 50 is preferably 200 μm or less.

[0085] The cathode electrode 30a according to the present embodiment has the same configuration as any of the cathode electrodes 30a according to the first to third embodiments.

[0086] 5.2 Operation The operation of the gas laser device 2 according to the present embodiment is the same as that of the comparative example, except that the action of the main electrode 30 is different.

[0087] 5.3 Action and Effect In the present embodiment, since the alumina sprayed coating 50 is formed on the discharge surface 31a and the end surfaces 31b of the anode electrode 30b, in addition to the effects of any of the first to third embodiments, an effect of suppressing deterioration of the anode electrode 30b due to the impact of discharge can be obtained. As a result, the main electrode 30 has a longer service life. This effect is known from Japanese Patent No. 4059758 and Japanese Patent No. 4367886.

[0088] 6. Method of Manufacturing an Electronic Device FIG. 18 schematically shows a configuration example of an exposure apparatus 100. 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 reticle pattern of a reticle (not shown) disposed on a reticle stage RT with pulsed laser light PL incident from a gas laser device 2. The projection optical system 106 reduces and projects the pulsed laser light PL that has passed through the reticle and forms an image on a workpiece (not shown) disposed on a workpiece table WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a photoresist.

[0089] The exposure apparatus 100 exposes the workpiece with the pulsed laser light PL reflecting the reticle pattern by synchronously translating the reticle stage RT and the workpiece table WT in parallel. After transferring the reticle pattern to the semiconductor wafer through the above-described exposure process, a semiconductor device can be manufactured through a plurality of processes. The semiconductor device is an example of the “electronic device” in the present disclosure.

[0090] Note that 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.

[0091] The above description is intended as an illustration only and not a limitation. Thus, it will be apparent to those skilled in the art that various changes may be made to the embodiments of the present disclosure without departing from the scope of the appended claims.

[0092] The terms used throughout this specification and the appended claims should be construed as terms that are "not limiting." For example, the terms "comprising" or "included" should be construed as "not limited to those described as being included." The term "having" should be construed as "not limited to those described as having." Also, the modifier "one" described in this specification and the appended claims should be construed to mean "at least one" or "one or more." Further, the term "at least one of A, B, and C" should be construed as "A", "B", "C", "A + B", "A + C", "B + C", or "A + B + C", and should further be construed to include combinations with things other than "A", "B", and "C".

Claims

1. A laser chamber configured to accommodate a pair of electrodes arranged to face each other in a first direction and to introduce a 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 in the second direction and an end surface provided at an end of the discharge portion in the second direction. The end surface is a part of a rotational ellipsoidal surface. Laser chamber.

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

3. The laser chamber according to claim 1, when a direction orthogonal to the first direction and the second direction is defined as a third direction, the rotation axis of the rotational ellipsoidal surface is an intersection line of a first cross section obtained by cutting the end portion with a plane parallel to the first direction and the third direction and a second cross section obtained by cutting the end portion with a plane parallel to the first direction and the second direction.

4. The laser chamber according to claim 3, wherein the cross-sectional shape of the end portion in the first cross section and the second cross section is the same.

5. The laser chamber according to claim 4, wherein the rotational ellipsoidal surface is a flattened ellipsoidal surface having a minor axis as the rotation axis.

6. The laser chamber according to claim 5, wherein when the major axis radius of the rotational ellipsoidal surface is L1 and the minor axis radius of the rotational ellipsoidal surface is L2, the relationship 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 composed of different components.

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

10. The laser chamber according to claim 9, wherein the insulating material is alumina 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 alumina sprayed film.

13. The laser chamber according to claim 12, wherein the thickness of the insulating film is 200 μm or less.

14. The laser chamber according to claim 1, One of the pair of electrodes is an anode electrode on which an alumina sprayed film with metal dispersed on the discharge surface and the end surface is formed.

15. The laser chamber according to claim 14, wherein the thickness of the alumina sprayed film is 200 μm or less.

16. The laser chamber according to claim 1, wherein the shoulder portion rectifies the laser gas.

17. A gas laser device comprising: a laser chamber configured to accommodate a pair of electrodes arranged to face each other in a first direction and to be capable of introducing a laser gas; a power supply device connected to the pair of electrodes; a processor configured to control 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 in the second direction and an end surface provided at an end of the discharge portion in the second direction, and the end surface is a part of an ellipsoidal surface.

18. A method for manufacturing an electronic device, wherein a laser gas is introduced into the laser chamber of the gas laser device, wherein the laser gas is introduced into the laser chamber of the gas laser device, a laser chamber configured to accommodate a pair of electrodes arranged to face each other in a first direction and to be capable of introducing a laser gas; a power supply device connected to the pair of electrodes; a processor configured to control 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 in the second direction and an end surface provided at an end of the discharge portion in the second direction, and the end surface is a part of an ellipsoidal surface. The laser light is generated by the gas laser device, the laser light is output to an exposure device, and the method includes exposing a photosensitive substrate to the laser light in the exposure device to manufacture an electronic device.

19. The method for manufacturing an electronic device according to claim 18,

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