Laser device and method of manufacturing electronic device

Abstract

To provide a laser device that is suppressed from varying in beam size.SOLUTION: A laser device comprises: an oscillation stage laser which generates and outputs a pulse laser beam; and an amplification stage laser which amplifies the pulse laser beam output from the oscillation stage laser. The amplification stage laser comprises: an optical resonator configured to serve as a transfer optical system; a first discharge electrode pair and a second discharge pair which are arranged across an optical path of the optical resonator apart from each other in a first direction crossing the optical path, and configured to discharge alternately; and a slit which is arranged at a transfer position of the transfer optical system, and limits beam size in a second direction orthogonal to the first direction of the pulse laser beam amplified by discharging of the first discharge electrode pair or second discharge electrode pair.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a laser apparatus and a method for manufacturing an electronic device. [Background technology]

[0002] In recent years, semiconductor exposure devices have been required to improve their resolution in response to the miniaturization and high integration of semiconductor integrated circuits. To this end, the wavelength of light emitted from exposure light sources has been shortened. For example, KrF excimer laser devices that output laser light with a wavelength of approximately 248 nm and ArF excimer laser devices that output laser light with a wavelength of approximately 193 nm are used as gas laser devices for exposure.

[0003] The spectral linewidth of the spontaneously oscillating light from KrF excimer laser devices and ArF excimer laser devices is as wide as 350 to 400 pm. Therefore, if a projection lens is constructed using a material that transmits ultraviolet light, such as KrF and ArF laser light, chromatic aberration may occur. As a result, resolution may decrease. Therefore, it is necessary to narrow the spectral linewidth of the laser light output from the gas laser device to a level where chromatic aberration is negligible. Therefore, a line narrowing module (LNM) containing a line narrowing element (e.g., an etalon or grating) may be installed inside the laser resonator of the gas laser device to narrow the spectral linewidth. Hereinafter, a gas laser device with a narrowed spectral linewidth is referred to as a line narrowing gas laser device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Summary of JP 2010-10551 A

[0005] A laser device according to one aspect of the present disclosure is a laser device comprising an oscillation-stage laser that generates and outputs pulsed laser light, and an amplification-stage laser that amplifies the pulsed laser light output from the oscillation-stage laser, wherein the amplification-stage laser comprises an optical resonator configured to serve as a transfer optical system, a first discharge electrode pair and a second discharge electrode pair that are arranged on either side of the optical path and spaced apart in a first direction that intersects with the optical path of the optical resonator, and are configured to discharge alternately, and a slit that is arranged at a transfer position of the transfer optical system and limits the beam size in a second direction perpendicular to the first direction of the pulsed laser light amplified by the discharge of either the first discharge electrode pair or the second discharge electrode pair.

[0006] A method for manufacturing an electronic device according to another aspect of the present disclosure includes generating laser light using a laser apparatus including an oscillation-stage laser that generates and outputs pulsed laser light, and an amplification-stage laser that amplifies the pulsed laser light output from the oscillation-stage laser, the amplification-stage laser including an optical resonator configured to be a transfer optical system, a first discharge electrode pair and a second discharge electrode pair that are arranged on either side of the optical path and spaced apart in a first direction that intersects the optical path of the optical resonator and configured to alternately discharge, and a slit that is arranged at a transfer position of the transfer optical system and limits the beam size in a second direction perpendicular to the first direction of the pulsed laser light amplified by the discharge of either the first discharge electrode pair or the second discharge electrode pair, outputting the laser light to an exposure apparatus, and exposing the laser light onto a photosensitive substrate in the exposure apparatus to manufacture an electronic device. [Brief explanation of the drawings]

[0007] Some embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a diagram schematically showing the configuration of a laser device according to a comparative example. [Figure 2] FIG. 2 is a diagram schematically illustrating the configuration of the laser device according to the first embodiment. [Figure 3] FIG. 3 is a diagram schematically illustrating the configuration of a laser device according to the second embodiment. [Figure 4]FIG. 4 is a cross-sectional view that schematically shows a cross section perpendicular to the optical path of a chamber in which a slit is arranged. [Figure 5] FIG. 5 is a diagram schematically illustrating the configuration of a laser device according to the third embodiment. [Figure 6] FIG. 6 is a diagram showing a schematic configuration of an exposure apparatus. Embodiment

[0008] -table of contents- 1. Overview of the laser device according to the comparative example 1.1 Configuration 1.2 Operation 1.3 Challenges 2. Embodiment 1 2.1 Configuration 2.2 Operation 2.3 Actions and Effects 3. Embodiment 2 3.1 Configuration 3.2 Operation 3.3 Actions and Effects 4. Embodiment 3 4.1 Configuration 4.2 Operation 4.3 Actions and Effects 5. Variations 6. Manufacturing methods for electronic devices 7.Other

[0009] 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. Furthermore, not all of the configurations and operations described in each embodiment are necessarily essential as the configurations and operations of the present disclosure. Note that the same components are given the same reference symbols, and redundant explanations will be omitted.

[0010] 1. Overview of the laser device according to the comparative example 1.1 Configuration 1 is a diagram illustrating a schematic configuration of a laser device 1 according to a comparative example. The comparative example of the present disclosure is a configuration that the applicant recognizes as being known only by the applicant, and is not a publicly known example that the applicant acknowledges. As shown in FIG. 1, the laser device 1 includes an oscillation-stage laser 10, a beam expander 20, high-reflection mirrors 21 and 22, an amplification-stage laser 30, and a monitor module 70.

[0011] The oscillation stage laser 10 includes a chamber 12, a line narrowing module (LNM) 14, and an output coupler (OC) 16. The LNM 14 and the OC 16 together form an optical resonator, and the chamber 12 is disposed on the optical path of the optical resonator.

[0012] A pair of discharge electrodes 18a, 18b are arranged inside the chamber 12. The discharge electrodes 18a, 18b are spaced a predetermined distance apart in the Y direction, which intersects with the optical path of the optical resonator, and are arranged with their longitudinal directions parallel to each other and their discharge surfaces facing each other across the optical path. In FIG. 1, the direction perpendicular to the paper surface is the Y direction. The Y direction corresponds to the discharge direction. In FIG. 1, the direction of the optical path of the optical resonator is the Z direction, and the direction perpendicular to the Y and Z directions is the X direction. The same applies to FIGS. 2 to 5. However, in FIG. 4, the direction perpendicular to the paper surface is the Z direction.

[0013] The oscillation stage laser 10 is equipped with an oscillation stage power supply including an oscillation stage high-voltage pulse generator (not shown) and a charger (not shown). The discharge electrodes 18a, 18b are connected to the oscillation stage power supply, and high-voltage pulses are applied to them by the oscillation stage power supply.

[0014] The chamber 12 is filled with laser gas. The laser gas is, for example, a mixed gas of argon (Ar) gas, fluorine (F) gas, and neon (Ne) gas. A cross-flow fan and a heat exchanger (not shown) are also disposed inside the chamber 12.

[0015] The chamber 12 is provided with windows (not shown) at both ends in the Z direction. The windows are located on the optical path of the pulsed laser light at the output portion of the chamber 12. The windows are transparent to the wavelength of the pulsed laser light (e.g., 193 nm). The material of the windows is, for example, calcium fluoride (CaF2).

[0016] The amplification-stage laser 30 includes a chamber 32, a rear mirror 33, and an OC 34. A high-reflection mirror 21, a beam expander 20, and a high-reflection mirror 22 are arranged in the optical path between the OC 16 of the oscillation-stage laser 10 and the rear mirror 33 of the amplification-stage laser 30.

[0017] The rear mirror 33 and the OC 34 together constitute an optical resonator, and the chamber 32 is disposed on the optical path of the optical resonator. Two pairs of discharge electrodes, 38a and 38b and 38c and 38d, are disposed inside the chamber 32. The discharge electrodes 38a and 38b and the discharge electrodes 38c and 38d are spaced a predetermined distance apart in the Y direction, which intersects with the optical path of the optical resonator, with their longitudinal directions parallel to each other and their discharge surfaces facing each other across the optical path. These two pairs of discharge electrodes alternately discharge, achieving high repetition rate operation.

[0018] The amplification stage laser 30 includes a first amplification stage power supply including a first amplification stage high-voltage pulse generator (not shown) and a first charger (not shown), and a second amplification stage power supply including a second amplification stage high-voltage pulse generator (not shown) and a second charger (not shown). Discharge electrodes 38a and 38b are connected to the first amplification stage power supply, and high-voltage pulses are applied to them by the first amplification stage power supply. Discharge electrodes 38c and 38d are connected to the second amplification stage power supply, and high-voltage pulses are applied to them by the second amplification stage power supply.

[0019] Because the amplification-stage laser 30 requires higher energy than the oscillation-stage laser 10, the separation distance between the discharge electrodes 38a, 38b and the separation distance between the discharge electrodes 38c, 38d of the amplification-stage laser 30 are each wider than the separation distance between the discharge electrodes 18a, 18b of the oscillation-stage laser 10. The separation distance between the discharge electrodes 38a, 38b and the separation distance between the discharge electrodes 38c, 38d may be the same distance. The electrode lengths of the discharge electrodes 38a, 38b and the discharge electrodes 38c, 38d may be the same. Electrode length refers to the length in the longitudinal direction of the discharge electrodes. In FIG. 1, the longitudinal direction of the discharge electrodes 38a, 38b, 38c, and 38d is the Z direction.

[0020] The beam expander 20 expands the beam size in the Y direction of the pulsed laser light output from the oscillation stage laser 10 to match the spacing between the respective electrode pairs of discharge electrodes 38a, 38b and discharge electrodes 38c, 38d of the amplification stage laser 30.

[0021] The chamber 32 is filled with the same laser gas as the chamber 12. Similar to the chamber 12, a cross-flow fan and a heat exchanger (not shown) are disposed inside the chamber 32, and windows (not shown) are disposed on both ends in the Z direction at the output portion of the chamber 32 on the optical path of the pulsed laser beam.

[0022] The monitor module 70 includes an energy detector (not shown) that detects the energy of the pulsed laser light output from the amplification stage laser 30, and a spectrum detector (not shown) that measures the wavelength and spectral linewidth.

[0023] 1.2 Operation The operation of the laser device 1 will be described with reference to Figure 1. When a high-voltage pulse is applied to the discharge electrodes 18a and 18b by the oscillation stage power supply, a discharge occurs between the discharge electrodes 18a and 18b, exciting the laser gas. Then, resonance occurs in the optical resonator formed by the LNM 14 and the OC 16, generating pulsed laser light. The LNM 14 is formed by an expanding prism (not shown) and a grating (diffraction grating) that is a wavelength selection element (not shown), and narrows the spectral width of the pulsed laser light.

[0024] The cross-flow fan circulates the laser gas within the chamber 12 and replaces the laser gas between the discharge electrodes 18a and 18b. The heat exchanger exhausts heat from the chamber 12.

[0025] The pulsed laser light transmitted through the OC 16 is expanded at least in the Y direction by the beam expander 20 , and is injected into the chamber 32 via the rear mirror 33 while the beam direction is changed by the high-reflection mirrors 21 and 22 .

[0026] At the timing when the pulsed laser light enters the discharge space between the discharge electrodes 38a and 38b, a high voltage pulse is applied by the first amplification stage power supply, causing a discharge between the discharge electrodes 38a and 38b and exciting the laser gas. Then, resonance occurs in the optical resonator formed by the rear mirror 33 and the OC 34, and the pulsed laser light injected from the oscillation-stage laser 10 is amplified.

[0027] Next, at the timing when the pulsed laser light is incident on the discharge space between the discharge electrodes 38c and 38d, a high voltage pulse is applied by the second amplification stage power supply, causing a discharge between the discharge electrodes 38c and 38d and exciting the laser gas. Then, the pulsed laser light incident on the amplification stage laser 30 resonates in the optical resonator formed by the rear mirror 33 and the OC 34, and the pulsed laser light injected from the oscillation stage laser 10 is amplified.

[0028] Discharges are alternately repeated by the respective discharge electrode pairs, the discharge electrodes 38a, 38b and the discharge electrodes 38c, 38d. The repetition frequency of the discharges of the discharge electrodes 18a, 18b in the oscillation-stage laser 10 is twice the repetition frequency of the discharges of the respective discharge electrode pairs, the discharge electrodes 38a, 38b and the discharge electrodes 38c, 38d in the amplification-stage laser 30.

[0029] The pulsed laser light output from the amplification stage laser 30 enters the monitor module 70. The monitor module 70 measures the energy, wavelength, and spectral linewidth of the pulsed laser light. The measurement results of the monitor module 70 are sent to a laser control processor (not shown). Based on the measurement results of the monitor module 70, the laser control processor controls the laser device 1 so as to achieve the target pulse energy, target wavelength, and target spectral linewidth.

[0030] 1.3 Challenges In the laser device 1, which alternately oscillates by shifting the discharge timing of two pairs of discharge electrodes arranged in the chamber 32 by half a period, the beam size changes between the pulsed laser light amplified by the discharge of the discharge electrodes 38a and 38b arranged on the rear mirror 33 side and the pulsed laser light amplified by the discharge of the discharge electrodes 38c and 38d arranged on the OC 34 side.

[0031] That is, the pulsed laser light amplified by the discharge of the discharge electrodes 38a and 38b on the rear mirror 33 side has a larger beam size than the pulsed laser light amplified by the discharge of the discharge electrodes 38c and 38d on the OC 34 side. The rate of change in the beam size in the X direction perpendicular to the discharge direction is larger than the rate of change in the beam size in the discharge direction (Y direction).

[0032] In an exposure device used in combination with the laser device 1, if pulsed laser light beams with different beam sizes are alternately output from the laser device 1, exposure performance is affected.

[0033] 2. Embodiment 1 2.1 Configuration Fig. 2 is a diagram schematically showing the configuration of a laser device 1A according to embodiment 1. Differences between the configuration shown in Fig. 2 and Fig. 1 will be described.

[0034] The laser device 1A does not have the high-reflection mirror 22 of the laser device 1, and includes an amplification-stage laser 30A instead of the amplification-stage laser 30. The amplification-stage laser 30A includes a chamber 32 and a ring resonator 50.

[0035] The ring resonator 50 is composed of an OC 52, a high-reflection mirror 54, a high-reflection mirror 56, a high-reflection mirror 58, a lens 62, and a lens 64. The ring resonator 50 is a transfer optical system. Each of the lenses 62 and 64 is a condenser lens, and when the focal length of each lens is f, the orbital distance of the ring resonator 50 may be 4f. Each of the lenses 62 and 64 is a spherical type.

[0036] The pulsed laser light output from the oscillation-stage laser 10 is incident on the amplification-stage laser 30A via the OC 52. The reflectance of the OC 52 is, for example, 10% to 20%.

[0037] OC52 is arranged to transmit a portion of the pulsed laser light output from beam expander 20 and make it incident on lens 62, and to transmit a portion of the pulsed laser light that has circulated around ring resonator 50 and is output from chamber 32. Another portion of the pulsed laser light output from beam expander 20 is reflected by OC52, combined with the pulsed laser light that has circulated around ring resonator 50 and passed through OC52, and output from amplification-stage laser 30A.

[0038] The lens 62 is disposed on the optical path between the OC 52 and the high-reflection mirror 54. The lens 64 is disposed on the optical path between the high-reflection mirror 56 and the high-reflection mirror 58.

[0039] The focus position of the pulsed laser light circulating in the ring resonator 50 by the lenses 62 and 64 is outside the chamber 32. The focus position may be, for example, between the high-reflection mirror 54 and the high-reflection mirror 56.

[0040] The pulsed laser light circulating in the ring resonator 50 enters the lens 62, has its beam direction changed by the high-reflection mirror 54, is focused, and is then reflected by the high-reflection mirror 56. The pulsed laser light reflected by the high-reflection mirror 56 passes through the lens 64, has its beam direction changed by the high-reflection mirror 58, and enters the chamber 32.

[0041] Discharge electrodes 38a and 38b, a slit 40, and discharge electrodes 38c and 38d are arranged inside the chamber 32. The discharge electrode pairs of the discharge electrodes 38a and 38b and the discharge electrodes 38c and 38d are spaced apart in the Y direction that intersects with the optical path of the ring resonator 50, with their longitudinal directions parallel to each other and their discharge surfaces facing each other across the optical path. Discharges occur alternately between the discharge electrodes 38a and 38b and the discharge electrodes 38c and 38d.

[0042] Chamber 32 is an example of a "first chamber" in the present disclosure. Discharge electrodes 38a and 38b are an example of a "first discharge electrode pair" in the present disclosure. Discharge electrodes 38c and 38d are an example of a "second discharge electrode pair" in the present disclosure. Lenses 62 and 64 are an example of "two condenser lenses" in the present disclosure.

[0043] The slit 40 is disposed at the transfer position of the transfer optical system. When attempting to realize the ring resonator 50 with the shortest possible circular optical path length, the transfer position is located between the electrode pair of discharge electrodes 38a and 38b and the electrode pair of discharge electrodes 38c and 38d.

[0044] The slit 40 limits the beam size in the X direction, which is orthogonal to the Y direction intersecting the optical path of the ring resonator 50, i.e., in the direction orthogonal to the discharge direction. The slit 40 may also limit the beam size in the Y direction intersecting the optical path of the ring resonator 50, i.e., in the discharge direction. In this case, the opening size of the slit 40 in the Y direction is the same as or shorter than the distance between the discharge electrodes 38a and 38b. Note that in the case of a slit 40 that limits the beam size only in the X direction, each of the lenses 62 and 64 may be a cylindrical lens. The Y direction is an example of a "first direction" in this disclosure. The X direction is an example of a "second direction" in this disclosure.

[0045] The slit 40 may be configured, for example, by two divided plates defining a gap as a beam passing region, or may be configured by a plate with a rectangular opening. The material of the plate (slit plate) that forms the light-shielding portion of the slit 40 may be an electrically insulating material that is resistant to fluorine gas, such as alumina ceramics. The other configurations may be the same as those in FIG. 1.

[0046] 2.2 Operation A portion of the pulsed laser light that enters the OC 52 via the beam expander 20 passes through the OC 52. The pulsed laser light that has passed through the OC 52 is collected by the lens 62, and after being focused between the high-reflection mirror 54 and the high-reflection mirror 56, continues to propagate while diverging. The propagating pulsed laser light changes its beam direction by the high-reflection mirror 56 and becomes a parallel beam by the lens 64. The parallel pulsed laser light enters the chamber 32.

[0047] Discharge electrodes 38a, 38b and discharge electrodes 38c, 38d alternately discharge, and the pulsed laser light circulating around the ring resonator 50 is amplified when it passes through the discharge space of one of the two pairs of discharge electrodes (discharge electrodes 38a, 38b and discharge electrodes 38c, 38d) for each revolution.

[0048] The beam size of the pulsed laser light circulating around the ring resonator 50 in the X direction perpendicular to the Y direction is limited by the slit 40 each time the pulsed laser light circulates around the ring resonator 50. In this way, the pulsed laser light having a beam size equivalent to the beam size at the transfer position of the ring resonator 50, which is the transfer optical system, is output from the OC 52. As a result, the pulsed laser light having a beam size in the X direction equivalent to the size of the slit 40 in the X direction (slit width) is output from the OC 52.

[0049] 2.3 Actions and Effects According to the laser device 1A of the first embodiment, the beam size in the X direction orthogonal to the discharge direction is limited by the slit 40, and pulsed laser light having a beam size equivalent to the beam size at the transfer position is output from the laser device 1A. As a result, in the laser device 1A including the amplification-stage laser 30A that alternately discharges two sets of discharge electrode pairs, it is possible to suppress changes in the beam size of the output pulsed laser light in the direction (X direction) orthogonal to the discharge direction (Y direction).

[0050] In the laser device 1A according to the first embodiment, when the slit 40 that also limits the beam size in the discharge direction is disposed, it is possible to suppress changes in the beam size of the output pulsed laser light in the discharge direction.

[0051] According to the laser apparatus 1A of the first embodiment, the slit 40 is arranged at the transfer position of the ring resonator 50, and therefore the beam size can be limited without affecting the beam divergence angle, compared to when the slit 40 is not arranged at the transfer position. Furthermore, according to the laser apparatus 1A of the first embodiment, the slit 40 is arranged at the transfer position of the ring resonator 50, and therefore energy loss is smaller, compared to when the slit 40 is arranged at a position other than the transfer position.

[0052] 3. Embodiment 2 3.1 Configuration Fig. 3 is a diagram schematically showing the configuration of a laser device 1B according to embodiment 2. Differences between the configuration shown in Fig. 3 and Fig. 2 will be described.

[0053] The laser device 1B includes an amplification-stage laser 30B instead of the amplification-stage laser 30A. The amplification-stage laser 30B includes a chamber 35, a chamber 36, and a ring resonator 50B.

[0054] Ring resonator 50B is composed of OC 66, high-reflection mirror 68, high-reflection mirror 72, high-reflection mirror 74, lens 76, lens 78, lens 82, and lens 84. Ring resonator 50B is a transfer optical system that is configured to transfer twice during one revolution, with two transfer positions.

[0055] Each of the lenses 76, 78, 82, and 84 is a condenser lens, and when the focal length of each lens is f, the circular distance of the ring resonator 50B may be 8f.

[0056] The pulsed laser light output from the oscillation-stage laser 10 is incident on the amplification-stage laser 30B via the OC 66. The reflectance of the OC 66 is, for example, 10% to 20%.

[0057] OC66 is arranged to transmit a portion of the pulsed laser light output from beam expander 20 and cause it to enter lens 76, and to transmit a portion of the pulsed laser light that has circulated around ring resonator 50B and is output from chamber 36. Another portion of the pulsed laser light output from beam expander 20 is reflected by OC66, combined with the pulsed laser light that has circulated around ring resonator 50B and passed through OC66, and output from amplification-stage laser 30B.

[0058] Lenses 76 and 78 are disposed on the optical path between OC 66 and high-reflection mirror 68. Lenses 82 and 84 are disposed on the optical path between high-reflection mirror 72 and high-reflection mirror 74. Chamber 35 is disposed on the optical path between high-reflection mirror 68 and high-reflection mirror 72. Chamber 36 is disposed on the optical path between high-reflection mirror 74 and OC 66.

[0059] Each of chambers 34 and 35 is filled with the same laser gas as chamber 12. Also, a cross-flow fan and a heat exchanger (not shown) are disposed inside each of chambers 34 and 35, similar to chamber 12, and windows (not shown) are disposed on both ends in the Z direction at the output portions of chambers 34 and 35 on the optical path of the pulsed laser light.

[0060] The focus position of the pulsed laser light circulating in the ring resonator 50B by the lenses 76, 78, 82, and 84 is outside the chamber 35 and the chamber 36. The focus position may be, for example, between the lenses 76 and 78 and between the lenses 82 and 84.

[0061] The pulsed laser light circulating in ring resonator 50B enters lens 76 via OC 66, is focused, passes through lens 78, and is changed in beam direction by high-reflection mirror 68 before entering chamber 35. The pulsed laser light output from chamber 35 has its beam direction changed by high-reflection mirror 72, is focused by lens 82, and passes through lens 84. The pulsed laser light that has passed through lens 84 is changed in beam direction by high-reflection mirror 74 before entering chamber 36.

[0062] Discharge electrodes 38a and 38b are disposed inside chamber 35. Discharge electrodes 38c and 38d and a slit 40 are disposed inside chamber 36. The discharge electrode pairs of discharge electrodes 38a and 38b and discharge electrodes 38c and 38d are spaced apart in a direction (Y direction) intersecting the optical path of ring resonator 50B, with their longitudinal directions parallel to each other and their discharge surfaces facing each other across the optical path. Discharge electrodes 38a and 38b and discharge electrodes 38c and 38d discharge alternately. Chamber 35 is an example of a "second chamber" in the present disclosure. Chamber 36 is an example of a "third chamber" in the present disclosure.

[0063] The slit 40 is disposed at the transfer position of the transfer optical system. The transfer position may be the position where the discharge electrodes 38c and 38d are disposed. While FIG. 3 illustrates an example in which the slit 40 is disposed at one of the two transfer positions where the discharge electrodes 38c and 38d are disposed, the transfer position where the slit 40 is disposed may be the position where the discharge electrodes 38a and 38b are disposed, or a slit 40 may be disposed at each of the two transfer positions. The opening size of the slit 40 when disposed in the chamber 35 is the same as the opening size of the slit 40 when disposed in the chamber 36. The other configurations may be the same as those shown in FIG. 2. The transfer position where the discharge electrodes 38a and 38b are disposed is an example of the "first position" in the present disclosure. The transfer position where the discharge electrodes 38c and 38d are disposed is an example of the "second position" in the present disclosure.

[0064] Fig. 4 is a cross-sectional view that schematically shows a cross section perpendicular to the optical path of the chamber 36 in which the slit 40 is arranged. Fig. 4 shows a cross-sectional view at a transfer position where the slit 40 is arranged. As shown in Fig. 4, the slit 40 may be configured such that a gap serving as a beam passage region is defined by two divided plates.

[0065] 3.2 Operation 3, the pulsed laser light transmitted through the OC 66 is collected and focused by a lens 76, and then collimated by a lens 78. The collimated pulsed laser light then has its beam direction changed by a high-reflection mirror 68 and enters the chamber 35.

[0066] The pulsed laser light output from chamber 35 has its beam direction changed by high-reflection mirror 72, is condensed and focused by lens 82, and then becomes parallel light by lens 84. The parallel pulsed laser light then has its beam direction changed by high-reflection mirror 74 and enters chamber 36.

[0067] The pulsed laser light circulating through the ring resonator 50B is amplified each time it passes through the discharge space of one of the two pairs of discharge electrodes 38a, 38b and the two pairs of discharge electrodes 38c, 38d.

[0068] The beam size of the pulsed laser light circulating around the ring resonator 50B in the X direction perpendicular to the Y direction is limited by the slit 40 each time it circulates. In this way, the pulsed laser light having a beam size equivalent to the beam size at the transfer position of the ring resonator 50, which is the transfer optical system, is output from the OC66. As a result, the pulsed laser light having a beam size in the X direction equivalent to the size (slit width) of the slit 40 in the X direction is output from the OC66. Other operations are the same as those of the laser device 1A.

[0069] 3.3 Actions and Effects The laser device 1B according to the second embodiment can provide the same effects as the laser device 1A. Furthermore, the chambers 35 and 36 in the second embodiment can be made smaller than the chamber 32 in the first embodiment.

[0070] 4. Embodiment 3 4.1 Configuration Fig. 5 is a diagram schematically showing the configuration of a laser device 1C according to embodiment 3. Differences between the configuration shown in Fig. 5 and Fig. 1 will be described.

[0071] The laser device 1C includes an amplification-stage laser 30C instead of the amplification-stage laser 30 of the laser device 1. The amplification-stage laser 30C includes a chamber 32 and a confocal resonator 50C.

[0072] The confocal resonator 50C is composed of a rear mirror 86 and an OC 88. The rear mirror 86 and the OC 88 each have a concave inner surface with a curvature radius equal to the length of the resonator. The reflectance of the OC 88 is, for example, 10% to 20%.

[0073] The pulsed laser light output from the oscillation-stage laser 10 is reflected by the high-reflection mirror 22 and enters the amplification-stage laser 30C through the rear mirror 86.

[0074] The confocal resonator 50C is a special transfer optical system in which the transfer position and the light collection position coincide with each other.

[0075] Discharge electrodes 38a and 38b, a slit 40, and discharge electrodes 38c and 38d are arranged inside the chamber 32. The configuration of the chamber 32 may be the same as that shown in FIG. 2. The slit 40 is arranged at a transfer position when the rear mirror 86 and the OC 88 that constitute the confocal resonator 50C are used as the transfer optical system. The transfer position may be between the discharge electrodes 38a and 38b and the discharge electrodes 38c and 38d. The chamber 32 shown in FIG. 5 is an example of the "fourth chamber" in this disclosure.

[0076] The slit 40 limits the beam size in the X direction, which is orthogonal to the Y direction intersecting the optical path of the confocal resonator 50C, i.e., in the direction orthogonal to the discharge direction. The slit 40 may also limit the beam size in the Y direction intersecting the optical path of the confocal resonator 50C, i.e., in the discharge direction. In this case, the opening size of the slit 40 in the Y direction is the same as or shorter than the spacing between the discharge electrodes 38a, 38b. The other configurations may be the same as those shown in FIG. 1.

[0077] 4.2 Operation In the laser device 1C, the pulsed laser light transmitted through the rear mirror 86 travels back and forth within the confocal resonator 50C. When the pulsed laser light travels from the rear mirror 86 to the OC88, it becomes parallel light. The light reflected by the OC88 is collected and focuses between the rear mirror 86 and the OC88, after which it propagates while expanding. The light reflected by the rear mirror 86 becomes parallel light and propagates toward the OC88.

[0078] The pulsed laser light traveling back and forth within the confocal resonator 50C is amplified when it passes through the discharge space of one of the two pairs of discharge electrodes 38a, 38b and 38c, 38d.

[0079] The pulsed laser light traveling back and forth within the confocal resonator 50C has its beam size limited by the slit 40 in the direction (X direction) perpendicular to the discharge direction (Y direction).

[0080] In this way, pulsed laser light having a beam size equivalent to the beam size at the transfer position of the confocal resonator 50C, which is the transfer optical system, is output from the OC 88. As a result, pulsed laser light having a beam size in the X direction equivalent to the size (slit width) of the slit 40 in the X direction is output from the OC 88. Other operations are the same as those of the laser device 1A.

[0081] 4.3 Actions and Effects The laser device 1C according to the third embodiment can provide the same effects as the laser device 1A. Furthermore, since the laser device 1C has a shorter cavity length than the laser device 1A, the number of revolutions within the discharge time increases, thereby enabling a larger laser output.

[0082] 5. Variations Instead of the oscillation stage laser 10, which is a narrow-band gas laser device, a solid-state laser system including a semiconductor laser and a wavelength conversion system may be used.

[0083] 6. Manufacturing methods for electronic devices FIG. 6 is a diagram showing a schematic configuration of an exposure apparatus 9. In FIG. 6, the exposure apparatus 9 includes an illumination optical system 90 and a projection optical system 92. The illumination optical system 90 illuminates a reticle pattern of a reticle (not shown) placed on a reticle stage RT with laser light incident from the laser apparatus 1A. The projection optical system 92 reduces and projects the laser light that has passed through the reticle, forming an image on a workpiece (not shown) placed on a workpiece table WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0084] The exposure apparatus 9 exposes the workpiece with laser light reflecting the reticle pattern by synchronously translating the reticle stage RT and the workpiece table WT. After the reticle pattern is transferred to the semiconductor wafer through the exposure process described above, a semiconductor device can be manufactured through multiple processes. A semiconductor device is an example of an "electronic device" in this disclosure. Laser light may be generated using laser apparatus 1B or laser apparatus 1C instead of laser apparatus 1A.

[0085] 7.Other The above description is intended to be illustrative rather than limiting. Thus, it will be apparent to one skilled in the art that modifications can be made to the disclosed embodiments without departing from the scope of the claims. It will also be apparent to one skilled in the art that the disclosed embodiments can be used in combination.

[0086] Terms used throughout this specification and claims should be construed as "open ended" unless expressly stated otherwise. For example, words such as "comprise," "have," "comprise," and "equip" should be construed as meaning "without excluding the presence of elements other than those listed." In addition, the modifier "a" should be construed as meaning "at least one" or "one or more." In addition, 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." Furthermore, it should be construed to include combinations of these with elements other than "A," "B," and "C."

Claims

1. an oscillation stage laser that generates and outputs pulsed laser light; an amplification-stage laser that amplifies the pulsed laser light output from the oscillation-stage laser, The amplification stage laser comprises: an optical resonator configured to be a transfer optical system; a first discharge electrode pair and a second discharge electrode pair, which are arranged to sandwich the optical path of the optical resonator and are spaced apart in a first direction intersecting the optical path, and which are configured to alternately discharge; a slit that is arranged at a transfer position of the transfer optical system and that limits a beam size in a second direction orthogonal to the first direction of the pulsed laser light amplified by discharge of either the first discharge electrode pair or the second discharge electrode pair. Laser device.

2. 2. The laser device according to claim 1, the optical resonator is a ring resonator; Laser device.

3. 3. The laser device according to claim 2, the amplification-stage laser includes a first chamber disposed on an optical path of the optical resonator; the first discharge electrode pair and the second discharge electrode pair are disposed inside the first chamber. Laser device.

4. 4. The laser device according to claim 3, the optical resonator includes two focusing lenses; the transfer position is between the first discharge electrode pair and the second discharge electrode pair; Laser device.

5. 5. The laser device according to claim 4, a focusing position of the pulsed laser light circulating in the ring resonator by the two focusing lenses is outside the first chamber; Laser device.

6. 4. The laser device according to claim 3, the slit further limits the beam size in the first direction. Laser device.

7. 3. The laser device according to claim 2, the amplification-stage laser includes a second chamber and a third chamber disposed on an optical path of the optical resonator; the first discharge electrode pair is disposed inside the second chamber; the second discharge electrode pair is disposed inside the third chamber; Laser device.

8. 8. The laser device according to claim 7, the optical resonator includes four focusing lenses; the transfer positions are a first position where the first discharge electrode pair is arranged and a second position where the second discharge electrode pair is arranged, the slit is disposed at least one of the first position and the second position. Laser device.

9. 9. The laser device according to claim 8, a focusing position of the pulsed laser light circulating in the ring resonator by the four focusing lenses is outside the second chamber and the third chamber; Laser device.

10. 2. The laser device according to claim 1, the optical resonator is a confocal resonator; Laser device.

11. 11. The laser device according to claim 10, the amplification stage laser includes a fourth chamber disposed on an optical path of the optical resonator; the first discharge electrode pair and the second discharge electrode pair are disposed inside the fourth chamber. Laser device.

12. 12. The laser device according to claim 11, the transfer position of the optical resonator is between the first discharge electrode pair and the second discharge electrode pair; Laser device.

13. 13. The laser device according to claim 12, the slit further limits the beam size in the first direction. Laser device.

14. 2. The laser device according to claim 1, The separation distance of the first discharge electrode pair is the same as the separation distance of the second discharge electrode pair. Laser device.

15. 2. The laser device according to claim 1, The electrode length of the first discharge electrode pair is the same as the electrode length of the second discharge electrode pair. Laser device.

16. 2. The laser device according to claim 1, the oscillation stage laser includes a chamber; A discharge electrode pair is disposed inside the chamber. Laser device.

17. 17. The laser device of claim 16, a separation distance between the first discharge electrode pair and the second discharge electrode pair is wider than a separation distance between the discharge electrode pairs of the oscillation-stage laser; Laser device.

18. 17. The laser device of claim 16, a repetition frequency of discharge of the discharge electrode pair is twice the repetition frequency of discharge of each of the first discharge electrode pair and the second discharge electrode pair; Laser device.

19. A method for manufacturing an electronic device, comprising: an oscillation stage laser that generates and outputs pulsed laser light; an amplification-stage laser that amplifies the pulsed laser light output from the oscillation-stage laser, The amplification stage laser comprises: an optical resonator configured to be a transfer optical system; a first discharge electrode pair and a second discharge electrode pair, which are arranged to sandwich the optical path of the optical resonator and are spaced apart in a first direction intersecting the optical path, and which are configured to alternately discharge; a slit that is arranged at a transfer position of the transfer optical system and that limits a beam size in a second direction orthogonal to the first direction of the pulsed laser light amplified by discharge of either the first discharge electrode pair or the second discharge electrode pair; generating a laser beam by a laser device comprising: outputting the laser light to an exposure device; exposing the laser light onto a photosensitive substrate in the exposure apparatus to manufacture an electronic device; A method for manufacturing electronic devices.

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