Pulse width extension device, laser device and method for manufacturing electronic device

Abstract

A pulse width expansion device according to one aspect of the present disclosure comprises: a first delay optical system, in which a first circulation optical path composed of a first beam splitter and a plurality of first concave mirrors is formed on a first plane; a second delay optical system, in which a second circulation optical path composed of a second beam splitter and a plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the length direction of the cross-sectional shape of the beam of the pulsed laser traveling in the second circulation optical path is orthogonal to the second plane.

Description

Technical Field

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

[0002] In recent years, in semiconductor exposure devices, as semiconductor integrated circuits become smaller and more highly integrated, there is a demand for improved resolution. Therefore, 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 a laser with a wavelength of about 248nm and an ArF excimer laser device that outputs a laser with a wavelength of about 193nm are used.

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

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-176358

[0007] Patent Document 2: U.S. Patent No. 7184204 Summary of the invention

[0008] A pulse width expansion device according to one aspect of the present disclosure comprises: a first delay optical system, which includes a first beam splitter and a plurality of first concave mirrors, wherein a first circulation optical path formed by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system, which includes a second beam splitter and a plurality of second concave mirrors, wherein a second circulation optical path formed by the second beam splitter and the plurality of second concave mirrors is formed on a second plane which is parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the length direction of the beam cross-sectional shape of the pulsed laser traveling in the second circulation optical path is orthogonal to the second plane.

[0009] A laser device according to another aspect of the present invention includes: a laser oscillator that outputs a pulsed laser; and a pulse width expansion device that is arranged on an optical path of the pulsed laser, wherein the pulse width expansion device has: a first delay optical system that includes a first beam splitter and a plurality of first concave mirrors, wherein a first circulation optical path formed by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system that includes a second beam splitter and a plurality of second concave mirrors, wherein a second circulation optical path formed by the second beam splitter and the plurality of second concave mirrors is formed on a second plane that is parallel to the first plane and different from the first plane; and a first beam rotation mechanism that is arranged on an optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the length direction of the beam cross-sectional shape of the pulsed laser traveling in the second circulation optical path is orthogonal to the second plane.

[0010] A method for manufacturing an electronic device according to another aspect of the present invention includes the following steps: generating a laser with an expanded pulse width by a laser device; outputting the laser to an exposure device; and exposing the laser on a photosensitive substrate in the exposure device to manufacture the electronic device, wherein the laser device comprises: a first delay optical system, which comprises a first beam splitter and a plurality of first concave mirrors, wherein a first circulating optical path formed by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system, which comprises a second beam splitter and a plurality of second concave mirrors, wherein a second circulating optical path formed by the second beam splitter and the plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on an optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the length direction of the beam cross-sectional shape of the pulsed laser traveling in the second circulating optical path is orthogonal to the second plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Hereinafter, several embodiments of the present disclosure will be described as simple examples with reference to the accompanying drawings.

[0012] Figure 1 A configuration example of a laser device according to a comparative example is schematically shown.

[0013] Figure 2 This is a plan view schematically showing the structure of the laser device according to the first embodiment.

[0014] Figure 3 This is a front view schematically showing the structure of the laser device according to the first embodiment.

[0015] Figure 4 This is a perspective view schematically showing the structure of the bulky optical pulse stretcher (L-OPS) according to the first embodiment.

[0016] Figure 5 This is a perspective view schematically showing the structure of the L-OPS according to the second embodiment.

[0017] Figure 6 This is a diagram schematically showing the propagation action of pulsed laser light replaced by a pair of concave mirrors with a pair of convex lenses.

[0018] Figure 7 Modification 1 of the beam rotation mechanism applied to L-OPS is shown.

[0019] Figure 8 Modification 2 of the beam rotation mechanism applied to L-OPS is shown.

[0020] Fig. 9 This is a plan view schematically showing the structure of a laser device according to a third embodiment.

[0021] Fig.10 This is a front view schematically showing the structure of the laser device according to the third embodiment.

[0022] Fig.11 This is a perspective view schematically showing the structure of the L-OPS according to the third embodiment.

[0023] Fig.12 A configuration example of an exposure device is schematically shown. DETAILED DESCRIPTION

[0024] -Table of contents-

[0025] 1. Overview of Laser Device of Comparative Example

[0026] 1.1 Structure

[0027] 1.2 Action

[0028] 1.3 Topics

[0029] 2. Implementation Method 1

[0030] 2.1 Structure

[0031] 2.2 Action

[0032] 2.3 Specific example of L-OPS

[0033] 2.3.1 Structure

[0034] 2.3.2 Action

[0035] 2.4 Effects

[0036] 2.5 Variations

[0037] 3. Implementation Method 2

[0038] 3.1 Structure

[0039] 3.2 Action

[0040] 3.3 Effects

[0041] 4. Modification 1 of the beam rotation mechanism

[0042] 4.1 Structure

[0043] 4.2 Action

[0044] 4.3 Effects

[0045] 5. Modification 2 of the beam rotation mechanism

[0046] 5.1 Structure

[0047] 5.2 Action

[0048] 5.3 Effects

[0049] 6. Implementation Method 3

[0050] 6.1 Structure

[0051] 6.2 Action

[0052] 6.3 Specific example of L-OPS

[0053] 6.3.1 Structure

[0054] 6.3.2 Action

[0055] 6.4 Effects

[0056] 6.5 Variations

[0057] 7. About the manufacturing method of electronic devices

[0058] 8. Others

[0059] Below, the embodiments of the present disclosure are described in detail with reference to the accompanying drawings. The embodiments described below show several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and actions described in each embodiment are not necessarily all necessary for the structures and actions of the present disclosure. In addition, the same reference numerals are marked on the same structural elements and repeated descriptions are omitted.

[0060] 1. Overview of Laser Device of Comparative Example

[0061] 1.1 Structure

[0062] Figure 1The structure of the laser device 2 of the comparative example is schematically shown. The comparative example disclosed in the present invention is a method that the applicant recognizes that only the applicant knows, and is not a known example acknowledged by the applicant himself. The laser device 2 includes a master oscillator (Master Oscillator: MO) 10, a MO beam steering unit 20, a power oscillator (Power Oscillator: PO) 30, a PO beam steering unit 40 and an optical pulse stretcher (Optical Pulse Stretcher: OPS) 50.

[0063] The master oscillator 10 includes a narrowband module (LNM) 11 , a cavity 14 and an output coupling mirror (Output Coupler: OC) 17 .

[0064] The LNM 11 includes a prism beam expander 12 for narrowing the spectral line width and a grating 13. The prism beam expander 12 and the grating 13 are arranged by Littrow so that the incident angle and the diffraction angle coincide with each other.

[0065] The output coupling mirror 17 is a reflection mirror having a reflectivity of 40% to 60%. The output coupling mirror 17 and the LNM 11 are arranged to constitute an optical resonator.

[0066] The cavity 14 is arranged on the optical path of the optical resonator. The cavity 14 includes a pair of discharge electrodes 15a, 15b, and two windows for the pulse laser to pass through, namely, window 16a and window 16b. The cavity 14 contains an excimer laser gas inside. The excimer laser gas may include, for example, Ar gas or Kr gas as a rare gas, F2 gas as a halogen gas, and Ne gas as a buffer gas.

[0067] The MO beam steering unit 20 includes a high reflection mirror 21 a and a high reflection mirror 21 b. The high reflection mirror 21 a and the high reflection mirror 21 b are arranged so that the pulse laser light output from the master oscillator 10 is incident on the power oscillator 30.

[0068] The power oscillator 30 includes a rear mirror 31, a cavity 32, and an output coupling mirror 35. The rear mirror 31 and the output coupling mirror 35 are configured to constitute an optical resonator.

[0069] The cavity 32 is arranged on the optical path of the optical resonator. The cavity 32 may have the same structure as the cavity 14 of the master oscillator 10. That is, the cavity 32 includes a pair of discharge electrodes 33a and 33b, and two windows, namely, window 34a and window 34b, through which the pulsed laser light passes. The cavity 32 contains excimer laser gas inside.

[0070] The rear mirror 31 is a reflective mirror having a reflectivity of 50% to 90%. The output coupling mirror 35 is a reflective mirror having a reflectivity of 10% to 30%.

[0071] The PO beam steering unit 40 includes a high reflection mirror 40 a and a high reflection mirror 40 b. The high reflection mirror 40 a and the high reflection mirror 40 b are arranged so that the pulse laser output from the power oscillator 30 is incident on the OPS 50 .

[0072] OPS50 includes a beam splitter 52 and four concave mirrors 54a to 54d. The beam splitter 52 is arranged on the optical path of the pulse laser output from the PO beam steering unit 40. The beam splitter 52 is a reflector that transmits a portion of the incident pulse laser and reflects the other pulse laser. The reflectivity of the beam splitter 52 is preferably 40% to 70%, more preferably about 60%. The beam splitter 52 allows the pulse laser that has passed through the beam splitter 52 to be output from the laser device 2.

[0073] The four concave mirrors 54a to 54d constitute a delay optical path of the pulse laser after being reflected by the first surface of the beam splitter 52. The pulse laser after being reflected by the first surface of the beam splitter 52 is arranged so that the beam is reflected by the four concave mirrors 54a to 54d and is imaged again by the beam splitter 52.

[0074] The four concave mirrors 54a to 54d may be concave mirrors whose respective focal lengths are all substantially equal. The focal length f of each of the concave mirrors 54a to 54d may correspond to the distance from the beam splitter 52 to the concave mirror 54a, for example.

[0075] The concave mirrors 54a and 54b are arranged so that the pulsed laser reflected by the first surface of the beam splitter 52 is reflected by the concave mirror 54a and incident on the concave mirror 54b. The concave mirrors 54a and 54b are arranged so that the pulsed laser reflected by the first surface of the beam splitter 52 is imaged as a first transfer image of the same magnification (1:1) as the image on the first surface of the beam splitter 52.

[0076] The concave mirror 54c and the concave mirror 54d are arranged so that the pulsed laser reflected by the concave mirror 54b is reflected by the concave mirror 54c and incident on the concave mirror 54d. Furthermore, the concave mirror 54d is arranged so that the pulsed laser reflected by the concave mirror 54d is incident on the second surface of the beam splitter 52 opposite to the first surface. The concave mirror 54c and the concave mirror 54d are arranged so that the first transfer image is imaged as the second transfer image in a 1:1 manner on the second surface of the beam splitter 52.

[0077] 1.2 Action

[0078] When discharge occurs in the cavity 14 of the master oscillator 10, the laser gas is excited, and pulsed laser light narrowed by the optical resonator composed of the output coupling mirror 17 and the LNM 11 is output from the output coupling mirror 17. The pulsed laser light passes through the MO beam steering unit 20 and is incident on the rear mirror 31 of the power oscillator 30 as seed light.

[0079] In synchronization with the timing of the incidence of the seed light after passing through the rear mirror 31, discharge is generated in the cavity 32. As a result, the laser gas is excited, the seed light is amplified by the Fabry-Perot type optical resonator composed of the output coupling mirror 35 and the rear mirror 31, and the amplified pulse laser is output from the output coupling mirror 35. The pulse laser output from the output coupling mirror 35 is incident on the OPS 50 via the PO beam steering unit 40.

[0080] The pulse laser light incident on OPS50 is incident on the first surface of beam splitter 52. A portion of the pulse laser light incident on the first surface of beam splitter 52 is transmitted through beam splitter 52 and output from OPS50 as zero-round (passed) pulse laser light that is not rounded in the delay optical path.

[0081] Of the pulsed laser light incident on the first surface of the beam splitter 52, the pulsed laser light reflected by the first surface of the beam splitter 52 enters the delay optical path and is reflected by the concave mirrors 54a and 54b. The light image of the pulsed laser light reflected by the first surface of the beam splitter 52 is imaged into a 1:1 first transfer image by the concave mirrors 54a and 54b. Then, the first transfer image is imaged into a 1:1 second transfer image by the concave mirrors 54c and 54d on the second surface of the beam splitter 52.

[0082] A portion of the pulsed laser light incident on the second surface of the beam splitter 52 from the concave mirror 54d is reflected by the second surface of the beam splitter 52 and output from the OPS50 as a pulsed laser light of 1 turn that makes 1 turn in the delayed optical path. The pulsed laser light of 1 turn is outputted delayed by a delay time Δt1 compared to the pulsed laser light of 0 turn. Assuming that the optical path length of the delayed optical path of the OPS50 is L OPS , assuming the speed of light is c, the delay time Δt1 can be expressed as Δt1 = L OPS / c.

[0083] Of the pulse laser light incident on the second surface of the beam splitter 52 as the second transfer image, the pulse laser light after passing through the beam splitter 52 further enters the delay optical path, is reflected by the four concave mirrors 54a, 54b, 54c, and 54d, and is incident again on the second surface of the beam splitter 52. Then, the pulse laser light reflected by the second surface of the beam splitter 52 is output from the OPS 50 as a two-turn pulse laser light that turns twice on the delay optical path. The two-turn pulse laser light is outputted with a delay time Δt1 compared to the one-turn pulse laser light.

[0084] Then, by repeatedly making the light go around the delay optical path, the OPS50 outputs pulse laser light of 0 turns, 1 turns, 2 turns, 3 turns, etc. The more the pulse laser light output from the OPS50 goes around the delay optical path, the lower the light intensity becomes.

[0085] The pulse lasers after the 1st cycle are delayed by an integral multiple of the delay time Δt1 with respect to the pulse lasers after the 0th cycle, and are synthesized and outputted, whereby the pulse waveforms are superimposed. In this way, the pulse width of the pulse laser is extended by the OPS 50.

[0086] The pulse laser light after passing through the OPS 50 passes through a monitor module (not shown) and is output from the laser device 2. The monitor module includes a beam splitter and a sensor (not shown), and measures the pulse energy, line width, wavelength, etc. of the pulse laser light.

[0087] exist Figure 1 In the example of having one stage OPS 50, the laser device 2 may include two or more stages of OPS. For example, one or more OPSs (not shown) may be arranged in series on the optical path of the pulse laser output from the OPS 50.

[0088] 1.3 Topics

[0089] The laser device 2 expands the pulse width of the pulse laser through the OPS50, thereby suppressing the generation of unevenness (speckle) on the surface of the workpiece. In the case where the workpiece is a wafer, speckles appear dispersedly on the wafer surface, so the size of the local exposure amount is generated, and the size of the exposure pattern changes. Speckle refers to light and dark spots generated by interference when the pulse laser is scattered in order to make the light intensity distribution of the pulse laser uniform. The image obtained by photographing the light and dark spots is called a speckle image. As an evaluation index of speckle, the following speckle contrast SC is generally used.

[0090] SC=σ(I) / Avg(I)

[0091] Here, σ(I) is the standard deviation of the intensity I in the speckle image, and Avg(I) is the average value of the intensity I.

[0092] When the pulse width is further greatly extended by using OPS in order to reduce the speckle contrast, a large OPS is required to generate an optical path difference over a very long distance. When a plurality of mirrors are used to reflect the pulse laser and extend the optical path length in order to construct a large OPS, the beam divergence in the direction parallel to the plane including the propagation optical path formed by the plurality of mirrors becomes large, and sometimes the pulse laser specifications required by the exposure device are not met.

[0093] exist Figure 1 In the orthogonal coordinate system, the height direction of the laser device 2 is assumed to be ( Figure 1 The longitudinal direction of the laser device 2 is the V-axis direction, and the longitudinal direction of the laser device 2 is the V-axis direction. Figure 1 The horizontal direction of the laser device 2 is the Z-axis direction, and the depth direction of the laser device 2 is the Z-axis direction. Figure 1 The direction perpendicular to the paper plane is the H-axis direction. Figure 1 In the case of the laser device 2 shown, the concave mirrors 54a to 54d of the OPS 50 are arranged so as to form a propagation optical path (delay optical path) on a plane parallel to a VZ plane including the V axis and the Z axis.

[0094] When constructing an OPS that produces a longer optical path difference, for example, when a plurality of concave mirrors not shown are further arranged along the VZ plane in the front or rear stage of OPS50 and the propagation optical path is expanded in the VZ plane, the beam divergence of the pulsed laser emitted from the laser device 2 in the V-axis direction parallel to the VZ plane becomes larger.

[0095] The beam divergence of the pulsed laser incident on the exposure device needs to meet the specifications determined by the exposure device. Therefore, when a large OPS is used instead of OPS50, or when a large OPS is used in addition to OPS50, it is required to configure the OPS so as to obtain a pulsed laser that meets the required specifications of the exposure device.

[0096] In addition, the space inside and around the laser device is limited, so the large OPS needs to be space-saving.

[0097] 2. Implementation Method 1

[0098] 2.1 Structure

[0099] Figure 2 is a plan view schematically showing the structure of the laser device 2A according to the first embodiment. Figure 3 This is a front view schematically showing the structure of the laser device 2A. In addition, regarding the "front" of the laser device 2A, the side of the outer peripheral surface of the laser device 2A where the outer cover panel (not shown) is opened widely for maintenance of the laser device 2A is referred to as the "front". When the outer cover panel of the laser device 2A is opened, the Figure 3 The side of the configuration structure inside such a device is called the "front side".

[0100] exist Figure 2 and Figure 3 In the application and Figure 1 In the same orthogonal coordinate system, the height direction of the laser device 2A is defined as the V-axis direction, the length direction of the laser device 2A is defined as the Z-axis direction, and the depth direction of the laser device 2A is defined as the H-axis direction. The V-axis direction may be parallel to the gravity direction, and the direction opposite to the gravity direction is defined as the "+V direction", and the gravity direction is defined as the "-V direction".

[0101] The laser device 2A has a substantially rectangular shape, and a beam outlet (not shown) of the laser device 2A is provided at Figure 3The right side of the image. Let the emission direction of the pulse laser emitted from the laser device 2A be the "+Z direction". Let the direction Figure 3 The direction in front of the paper surface is the "+H direction".

[0102] The laser device 2A has a master oscillator 10, an MO beam steering unit 20, a power oscillator 30, and an OPS 50. These elements can be connected to Figure 1 The structure of the laser device 2 shown is the same. The master oscillator 10 or the combination of the master oscillator 10 and the power oscillator 30 is an example of a "laser oscillator" in the present disclosure. Figure 2 and Figure 3 The laser device 2A shown is for Figure 1 The differences between the comparative examples shown are described below.

[0103] The laser device 2A has a large optical pulse stretcher 100 (hereinafter referred to as "L-OPS100"), which is used to generate a long-distance optical path difference to expand the pulse width. L-OPS100 is arranged on the back side of the laser device 2A. When viewed from the front, the "back side" is the back side, which is the opposite side to the front side. A specific structural example of L-OPS100 is used. Figure 4 The laser device 2A replaces Figure 1 Instead of the PO beam steering unit 40 , a PO beam steering unit 42 is provided.

[0104] The PO beam steering unit 42 includes a high reflection mirror 44 a , a high reflection mirror 44 b , and a high reflection mirror 44 c to exchange light with the L-OPS 100 .

[0105] The high reflection mirror 44a is configured to reflect the pulse laser output from the power oscillator 30 and make it incident on the high reflection mirror 44b. The high reflection mirror 44b is configured to reflect the pulse laser after being reflected by the high reflection mirror 44a and make it incident on the first beam splitter BS1 of the L-OPS100. The high reflection mirror 44c is configured to reflect the pulse laser output from the L-OPS100 and make it incident on the OPS50.

[0106] 2.2 Action

[0107] The pulse laser light emitted from the power oscillator 30 has its propagation direction changed by the high reflection mirrors 44 a and 44 b of the PO beam steering unit 42 and is incident on the L-OPS 100 at the rear side of the laser device 2A.

[0108] The pulse laser light incident on the L-OPS 100 is expanded in pulse width by the L-OPS 100 and returns to the PO beam steering unit 42 .

[0109] The pulse laser beam returned to the PO beam steering unit 42 has its propagation direction changed by the high reflection mirror 44c and enters the OPS 50. The pulse laser beam entering the OPS 50 has its pulse width further expanded by the OPS 50 and is emitted from the laser device 2A.

[0110] 2.3 Specific example of L-OPS

[0111] 2.3.1 Structure

[0112] Figure 4 1 is a perspective view schematically showing the structure of the L-OPS 100. The L-OPS 100 includes a first beam splitter BS1, a plurality of concave mirrors 111 to 116, high reflective mirrors 121 and 122, a second beam splitter BS2, a plurality of concave mirrors 131 to 134, and high reflective mirrors 141 to 143.

[0113] The first delay optical system including the first circulating optical path LOP1 is formed by the first beam splitter BS1 and a plurality of concave mirrors 111 to 116. The beam rotation mechanism 120 for rotating the beam of the pulsed laser is formed by the high reflection mirrors 121 and 122. The second delay optical system including the second circulating optical path LOP2 is formed by the second beam splitter BS2 and a plurality of concave mirrors 131 to 134. The high reflection mirrors 141 to 143 form a return propagation optical path BOP for returning the pulsed laser after passing through the first circulating optical path LOP1 and the second circulating optical path LOP2 to the PO beam steering unit 42.

[0114] In addition, Figure 4 In the figure, the optical path of the pulsed laser propagated by the high reflection mirrors 44a, 44b, 121, 122, 141, 142, 143 and 44c is represented by a thick solid line, the first circulation optical path LOP1 is represented by a thin solid line, and the second circulation optical path LOP2 is represented by a single-dot chain line.

[0115] In addition, Figure 4 In the figure, the rectangular symbol shown on the optical path of the pulsed laser schematically represents the beam cross-sectional shape of the pulsed laser propagating in the optical path. The "beam cross-sectional shape" is the shape of the cross-sectional profile of the beam cross section perpendicular to the beam axis. Hereinafter, the term "beam cross section" is used as a synonym for "cross-sectional profile of the beam" or "beam cross-sectional shape". The long side direction of the rectangle is the length direction of the beam cross section, and the short side direction of the rectangle is the short side direction of the beam cross section.

[0116] For example, the pulse laser incident on the high reflection mirror 44a has a longitudinal beam shape in which the length direction of the beam cross section is parallel to the V-axis direction. The high reflection mirror 44a is configured so that the incident pulse laser is reflected along the V-axis direction ( Figure 4The high reflection mirror 44b is configured so that the pulse laser from the high reflection mirror 44a is reflected along the H-axis direction ( Figure 4 The pulse laser light emitted from the high reflection mirror 44b has a horizontally long beam shape in which the longitudinal direction of the beam cross section is perpendicular to the V-axis direction.

[0117] The combination of the high reflector 44a and the high reflector 44b constitutes a beam rotation mechanism 43, which rotates the pulsed laser to convert the longitudinally long beam into a transversely long beam. In addition, here, the description of "rotating" includes the meaning of adjusting the direction of the longitudinal direction and the short side direction of the beam cross section relative to the beam axis.

[0118] The first beam splitter BS1 is arranged on the optical path between the high reflector 44b and the high reflector 121. The concave mirrors 111 to 116 form the first circulation optical path LOP1, which becomes a delayed optical path for the propagation of the pulsed laser after being reflected by the first beam splitter BS1. The concave mirrors 111 to 116 can be concave mirrors with substantially equal focal lengths. The focal length f1 of each concave mirror 111 to 116 can be, for example, equivalent to the distance from the first beam splitter BS1 to the concave mirror 111. It is arranged so that the pulsed laser after being reflected by the first beam splitter BS1 is reflected in the order of the concave mirrors 111, 112, 113, 114, 115 and 116, and the beam is imaged again at the first beam splitter BS1.

[0119] exist Figure 4 In the figure, the first circulating optical path LOP1 is formed on the same plane parallel to the VZ plane. That is, the first beam splitter BS1 and the concave mirrors 111 to 116 are configured to form the first circulating optical path LOP1 on the same plane parallel to the VZ plane. In addition, the description of "the same plane" may include an allowable range to the extent that it can be substantially regarded as the same plane. In addition, "the optical path is formed on the same plane" may also be changed to "the plane containing the optical path is a single plane", or "the optical path is formed in the same plane". The plane on which the first circulating optical path LOP1 is formed is called the "first circulating optical path plane". The first circulating optical path plane may also be changed to the plane containing the first circulating optical path LOP1. The first circulating optical path plane is an example of the "first plane" in the present disclosure.

[0120] The high reflection mirror 121 is arranged so as to reflect the pulse laser light emitted from the first beam splitter BS1 and make it incident on the high reflection mirror 122. The high reflection mirror 122 is arranged so as to reflect the pulse laser light incident from the high reflection mirror 121 and make it incident on the second beam splitter BS2.

[0121] The second beam splitter BS2 is arranged on the optical path between the high reflection mirror 122 and the high reflection mirror 141. Alternatively, the second beam splitter BS2 may be arranged on the optical path between the high reflection mirror 142 and the high reflection mirror 143.

[0122] The concave mirrors 131 to 134 form a second circulating optical path LOP2, which becomes a delayed optical path for the propagation of the pulsed laser after being reflected by the second beam splitter BS2. The concave mirrors 131 to 134 can be concave mirrors whose respective focal lengths are all approximately equal. For example, the focal length f2 of each concave mirror 131 to 134 can be equivalent to the distance from the second beam splitter BS2 to the concave mirror 131. It is configured so that the pulsed laser after being reflected by the second beam splitter BS2 is reflected in the order of the concave mirrors 131, 132, 133 and 134, and the beam is imaged again in the second beam splitter BS2.

[0123] The second circulating optical path LOP2 is formed on a plane parallel to the VZ plane. The plane on which the second circulating optical path LOP2 is formed is called the second circulating optical path plane. The second circulating optical path plane can also be renamed as the plane containing the second circulating optical path LOP2. The second circulating optical path plane is a plane parallel to the first circulating optical path plane and different from (not the same as) the first circulating optical path plane. The second beam splitter BS2 and the concave mirrors 131 to 134 are configured to form the second circulating optical path LOP2 on the same plane parallel to the VZ plane. The second circulating optical path plane is an example of the "second plane" in the present disclosure.

[0124] The concave mirrors 111, 115, 113, 131 and 133 and the concave mirrors 116, 112, 114, 134 and 132 are respectively arranged to face each other at both ends of the length direction of the laser device 2A. Figure 2 The middle is the horizontal direction (Z-axis direction).

[0125] That is, the concave mirror 111, the concave mirror 115, and the concave mirror 113 are arranged in a row along the V-axis direction in the order of the concave mirror 111, the concave mirror 115, and the concave mirror 113 and are arranged at one end portion in the longitudinal direction of the laser device 2A ( Figure 2 The concave mirror 116, the concave mirror 112 and the concave mirror 114 are arranged in a row along the V-axis direction in the order of the concave mirror 116, the concave mirror 112 and the concave mirror 114 and are arranged at the other end in the longitudinal direction of the laser device 2A ( Figure 2 The left end in FIG. 1 is referred to as the second end hereinafter. The concave mirror 111 and the concave mirror 116 are arranged at positions facing each other with the first beam splitter BS1 interposed therebetween.

[0126] Similarly, the concave mirror 131 and the concave mirror 133 are arranged in a row along the V-axis direction in the order of the concave mirror 131 and the concave mirror 133 and are arranged at the first end of the length direction of the laser device 2A. The concave mirror 134 and the concave mirror 132 are arranged in a row along the V-axis direction in the order of the concave mirror 134 and the concave mirror 132 and are arranged at the second end of the length direction of the laser device 2A. The concave mirror 131 and the concave mirror 134 are arranged at positions opposite to each other across the second beam splitter BS2.

[0127] The propagation optical path of the beam rotation mechanism 120 formed by the high reflection mirrors 121 and 122, and the return propagation optical path BOP formed by the high reflection mirrors 141 to 143 are formed on the same plane as the second circulation optical path LOP2. That is, the high reflection mirrors 121, 122 and the high reflection mirrors 141 to 143 are arranged so that the propagation optical path of the pulse laser from the high reflection mirror 121 to the second beam splitter BS2 via the high reflection mirror 122 and the return propagation optical path BOP from the second beam splitter BS2 to the high reflection mirror 141, 142 to the high reflection mirror 143 are formed on the second circulation optical path plane.

[0128] L-OPS100 is an example of a “pulse width expansion device” in the present disclosure. The beam rotation mechanism 120 is an example of a “first beam rotation mechanism” in the present disclosure. The high reflector 121 and the high reflector 122 are examples of “two or more mirrors” constituting the “first beam rotation mechanism” in the present disclosure, and the high reflector 121 and 122 are examples of “mirrors” constituting the “first beam rotation mechanism” in the present disclosure, respectively. The beam rotation mechanism 43 is an example of a “second beam rotation mechanism” in the present disclosure. In addition, the high reflector 44a and the high reflector 44b are examples of “two or more mirrors” constituting the “second beam rotation mechanism” in the present disclosure, and the high reflector 44a and 44b are examples of “mirrors” constituting the “second beam rotation mechanism” in the present disclosure, respectively. The high-reflection mirrors 141 to 143 are examples of the “return propagation optical system” in the present disclosure, and the return propagation optical path BOP is an example of the “optical path formed in the return propagation optical system” in the present disclosure.

[0129] The H-axis direction is an example of the “first axis direction” in the present disclosure. The Z-axis direction is an example of the “second axis direction” in the present disclosure. The V-axis direction is an example of the “third axis direction” in the present disclosure. Concave mirrors 111 to 116 are examples of the “first concave mirror” in the present disclosure. Concave mirrors 131 to 134 are examples of the “second concave mirror” in the present disclosure.

[0130] 2.3.2 Action

[0131] The beam rotation mechanism 43 composed of high reflection mirrors 44a and 44b of the PO beam steering unit 42 rotates the pulse laser so that the longitudinal direction of the beam cross section of the pulse laser traveling in the first circulation optical path LOP1 is orthogonal to the first circulation optical path plane.

[0132] The pulse laser emitted from the beam rotation mechanism 43 is incident on the first beam splitter BS1. After being reflected by the first surface of the first beam splitter BS1, the pulse laser is reflected in the order of the concave mirror 111, the concave mirror 112, the concave mirror 113, the concave mirror 114, the concave mirror 115, and the concave mirror 116, and propagates in the first circulating optical path LOP1. The pulse laser propagating in the first circulating optical path LOP1 maintains a beam shape in which the length direction of the beam cross section is orthogonal to the plane of the first circulating optical path and circulates in the first circulating optical path LOP1.

[0133] That is, the pulse laser light propagating through the first circulation optical path LOP1 circulates through the first circulation optical path LOP1 in a beam shape in which the short side direction of the beam cross section is parallel to the first circulation optical path plane.

[0134] The pulse laser propagating in the first circulation optical path LOP1 is incident on the first beam splitter BS1 again from the concave mirror 116. Of the pulse lasers that are incident on the first beam splitter BS1 again after circulating in the first circulation optical path LOP1, the pulse lasers that pass through the second surface of the first beam splitter BS1 propagate again in the first circulation optical path LOP1.

[0135] On the other hand, among the pulse lasers that are circled in the first loop optical path LOP1 and incident on the first beam splitter BS1 again, the pulse lasers that are reflected on the second surface of the first beam splitter BS1 are synthesized with the pulse lasers of the 0th circle after passing through the first surface of the first beam splitter BS1 and are incident on the high reflection mirror 121 of the beam rotation mechanism 120.

[0136] The pulse laser light incident on the beam rotation mechanism 120 is reflected by the high reflection mirrors 121 and 122 and rotated so that the longitudinal direction of the beam cross section of the pulse laser light propagating in the second circulation optical path LOP2 is orthogonal to the second circulation optical path plane.

[0137] The pulse laser emitted from the beam rotation mechanism 120 is incident on the first surface of the second beam splitter BS2, and the pulse laser reflected by the first surface of the second beam splitter BS2 propagates in the second circulation optical path LOP2. The pulse laser after passing through the first surface of the second beam splitter BS2 is emitted from the second beam splitter BS2 as zero-surround light and is incident on the high-reflection mirror 141. The pulse laser propagated in the second circulation optical path LOP2 is incident on the second beam splitter BS2 again. Among the pulse lasers that surround the second circulation optical path LOP2 and are incident on the second beam splitter BS2 again, the pulse laser after passing through the second surface of the second beam splitter BS2 propagates again in the second circulation optical path LOP2.

[0138] On the other hand, the pulse laser that is incident on the second beam splitter BS2 again after being reflected on the second surface of the second beam splitter BS2 leaves the second optical path LOP2 and is incident on the high reflection mirror 141. The pulse laser that is incident on the high reflection mirror 141 from the second beam splitter BS2 is reflected in the order of the high reflection mirrors 141, 142, and 143, and returns to the high reflection mirror 44c of the PO beam steering unit 42. The pulse laser reflected by the high reflection mirror 44c is incident on OPS50. The operation of OPS50 is as follows: Figure 1 As described in .

[0139] The pulse laser emitted from the OPS 50 is incident on an exposure device (not shown). The conditions of the beam divergence of the pulse laser incident on the exposure device are determined so that the workpiece is appropriately exposed in the exposure device.

[0140] The pulse laser propagating in the first optical loop LOP1 and the second optical loop LOP2 in the L-OPS 100 propagates while being reflected by the multiple concave mirrors 111 to 116 and the concave mirrors 131 to 134, thereby expanding the beam divergence in the short side direction of the beam cross section. However, the margin of the beam divergence specification required by the exposure device in the short side direction is larger than that in the long direction. This is because the beam divergence in the short side direction of the beam cross section of the pulse laser output from the power oscillator 30 is smaller than the beam divergence in the long direction.

[0141] In the laser device 2A of embodiment 1, the pulsed laser is rotated by the beam rotation mechanisms 43 and 120 so that the short side direction of the beam cross-section having a larger margin than the requirements of the exposure device is parallel to the respective circulating optical path planes of the first circulating optical path LOP1 and the second circulating optical path LOP2, and is incident on the first circulating optical path LOP1 and the second circulating optical path LOP2.

[0142] 2.4 Effects

[0143] According to the L-OPS 100 and the laser device 2A including the L-OPS 100 in the first embodiment, the following effects are obtained.

[0144] (1) The pulsed laser light can be greatly extended through the first and second optical loop paths LOP1 and LOP2 of the L-OPS 100. The laser device 2A can generate laser light with extended pulse width, and can reduce speckle contrast.

[0145] (2) The beam is rotated using the beam rotation mechanisms 43 and 120 so that the length direction of the beam cross section of the pulsed laser is orthogonal to the first circulation optical path LOP1 and the second circulation optical path LOP2, respectively. Thus, the short side direction of the beam cross section having a larger margin relative to the specification is parallel to the surface including the propagation optical path, which can relatively reduce the effect of the expansion of the beam divergence.

[0146] (3) The second optical path LOP2, the incident optical path for the pulsed laser to enter the second optical path LOP2 from the high reflection mirror 121, and the return propagation optical path BOP are arranged on the same plane, thereby reducing the thickness direction ( Figure 2 to Figure 4 The space (in the center is the H-axis direction) is

[0147] (4) L-OPS 100 is arranged on the back side of the laser device 2A, thereby not changing the total height of the laser device 2A body from the laser device 2 of the comparative example ( Figure 3 The dimension in the V-axis direction is sufficient.

[0148] (5) The L-OPS 100 is disposed on the back side of the laser device 2A, thereby improving the assemblability and adjustability.

[0149] 2.5 Variations

[0150] In the first embodiment, a structure is described in which a pulsed laser is incident from the PO beam steering unit 42 to the L-OPS 100, and the pulsed laser after the pulse width is expanded is returned to the PO beam steering unit 42 by the L-OPS 100. However, a part or all of the PO beam steering unit 42 may also be included in the structure of the L-OPS 100. For example, Figure 4 The beam rotation mechanism 43 shown may also be included in the structure of the L-OPS 100 .

[0151] exist Figure 4 In FIG. 1 , an example of using six concave mirrors 111 to 116 to form the first circulating optical path LOP1 is shown, but the number of concave mirrors forming the first circulating optical path LOP1 is not limited to this example. Preferably, the number of concave mirrors forming the first circulating optical path LOP1 is an even number, and more preferably, an even number of 4 or more.

[0152] Likewise, in Figure 4 In FIG. 1 , an example of using four concave mirrors 131 to 134 to form the second circulating optical path LOP2 is shown, but the number of concave mirrors constituting the second circulating optical path LOP2 is not limited to this example. Preferably, the number of concave mirrors constituting the second circulating optical path LOP2 is an even number, and more preferably, an even number of 4 or more.

[0153] When the number of concave mirrors constituting the first circulation optical path LOP1 is 2n, the 2n concave mirrors constituting the first circulation optical path LOP1 are divided into rows of n concave mirrors, and the rows of n concave mirrors are separated from each other in the Z-axis direction and arranged facing each other. In each single-side mirror row in the facing arrangement structure, n concave mirrors are arranged side by side in the V-axis direction. Here, n is an integer greater than 2.

[0154] Similarly, when the number of concave mirrors constituting the second circulating optical path LOP2 is 2m, the 2m concave mirrors constituting the second circulating optical path LOP2 are divided into m columns of concave mirrors, and the m columns of concave mirrors are separated from each other in the Z-axis direction and arranged facing each other. In each single-side mirror column in the facing arrangement structure, the m concave mirrors are arranged side by side in the V-axis direction. Here, m is an integer greater than 2. Figure 4 This is an example where n=3 and m=2.

[0155] 3. Implementation Method 2

[0156] 3.1 Structure

[0157] Figure 5 This is a perspective view schematically showing the structure of L-OPS100B according to Embodiment 2. Figure 4 L-OPS100 described in Figure 5 L-OPS100B shown. About Figure 5 The structure shown is Figure 4 The differences are explained.

[0158] Figure 5 The L-OPS100B shown replaces Figure 4 The six concave mirrors 111 to 116 described in the above description are replaced by eight concave mirrors 111 to 118. The concave mirrors 111 to 118 form a first circulating optical path LOP1B, which becomes a delayed optical path for propagating the pulsed laser after being reflected by the first beam splitter BS1. The concave mirrors 111 to 118 can be concave mirrors with substantially equal focal lengths. The configuration is such that the pulsed laser after being reflected by the first beam splitter BS1 is reflected in the order of the concave mirrors 111, 112, 113, 114, 115, 116, 117, and 118, and the beam is imaged again at the first beam splitter BS1.

[0159] exist Figure 4 In the L-OPS100 described in the above, six concave mirrors 111 to 116 are used to form the first optical path LOP1. Figure 5 In the L-OPS100B shown, eight concave mirrors 111 to 118 are used to form the first circulation optical path LOP1B.

[0160] That is, in Figure 5 In the L-OPS100B shown, concave mirrors 111 to 118 and concave mirrors 131 to 134 are arranged so that there are eight concave mirrors constituting the first circulating optical path LOP1B, and four concave mirrors constituting the second circulating optical path LOP2, and the number of concave mirrors arranged on one side facing each other in the length direction of the laser device 2A is an even number.

[0161] like Figure 5 As shown, the concave mirrors 111, 117, 113 and 115 and the concave mirrors 118, 112, 116 and 114 are respectively arranged to face each other at both ends of the length direction (Z-axis direction) of the laser device 2A. The concave mirrors 111, 117, 113 and 115 are arranged in a row along the V-axis direction in the order of the concave mirrors 111, 117, 113 and 115 and are arranged at the first end of the length direction of the laser device 2A. The concave mirrors 118, 112, 116 and 114 are arranged in a row along the V-axis direction in the order of the concave mirrors 118, 112, 116 and 114 and are arranged at the second end of the length direction of the laser device 2A. The concave mirror 111 and the concave mirror 118 are arranged at positions opposite to each other with the first beam splitter BS1 interposed therebetween. The concave mirror 117 is arranged opposite to the concave mirror 112, the concave mirror 113 is arranged opposite to the concave mirror 116, and the concave mirror 115 is arranged opposite to the concave mirror 114. The first loop optical path LOP1B is formed on the same plane parallel to the VZ plane. Other structures can be Figure 4 The structures shown are the same.

[0162] The number of concave mirrors constituting the second optical path LOP2 is Figure 4 There are also four concave mirrors arranged so as to face each other in the longitudinal direction of the laser device 2A, and the number of concave mirrors arranged on one side is an even number.

[0163] 3.2 Action

[0164] In the first loop optical path LOP1B, the pulse laser light is propagated while the image is inverted by a pair of concave mirrors. Figure 6 FIG. 1 is a diagram schematically showing the propagation action of a pair of concave mirrors on a pulsed laser. Figure 6 In the figure, a pair of concave mirrors is replaced by a pair of convex lenses. Figure 6The convex lens 211 and the convex lens 212 shown are equivalent to the concave mirror 111 and the concave mirror 112, for example.

[0165] exist Figure 5 In the case of the first circulating optical path LOP1B shown in the figure, the number of concave mirrors on one side of the concave mirrors 111 to 118 arranged facing each other in the Z-axis direction is an even number, so that the number of pairs of concave mirrors for image inversion is an even number, and the image of the pulsed laser (surround light) propagating in the first circulating optical path LOP1B when it merges again at the first beam splitter BS1 is not inverted relative to the pulsed laser (through light) of the zero surround after passing through the first beam splitter BS1. That is, it is sufficient to configure an even number of pairs of concave mirrors for image inversion, Figure 5 The concave mirrors 111 to 118 shown are examples of arranging four sets of a pair of concave mirrors for inverting an image.

[0166] The same is true for the second circulating optical path LOP2. The number of concave mirrors on one side of the concave mirrors 131 to 134 arranged face to face in the Z-axis direction is an even number. Therefore, the number of pairs of concave mirrors for image inversion is an even number. When the pulsed laser (surround light) propagating in the second circulating optical path LOP2 merges again at the second beam splitter BS2, the image of the pulsed laser (surround light) propagating in the second circulating optical path LOP2 is not inverted relative to the 0-surround pulsed laser (passing light) after passing through the second beam splitter BS2. Figure 5 The concave mirrors 131 to 134 shown are examples of arranging two sets of a pair of concave mirrors for inverting an image.

[0167] 3.3 Effects

[0168] According to L-OPS100B of embodiment 2, in the respective circulating optical paths of the first circulating optical path LOP1B and the second circulating optical path LOP2, the image of the circulating light is not inverted relative to the passing light, and therefore the direction of the circulating light will not be in the opposite direction to the direction of the passing light. When the circulating light and the passing light are overlapped, the apparent beam size and divergence can be suppressed from increasing.

[0169] 4. Modification 1 of the beam rotation mechanism

[0170] 4.1 Structure

[0171] Figure 7 A modification 1 of the beam rotating mechanism 120 is shown. Figure 4 and Figure 5 The beam rotation mechanism 120 shown is used Figure 7 Such a beam rotation mechanism 123 is shown.

[0172] The beam rotation mechanism 123 may be composed of three or more high-reflection mirrors. For example, the beam rotation mechanism 123 may be composed of four high-reflection mirrors 124a, 124b, 124c, and 124d.

[0173] The high reflective mirror 124a is configured to Figure 7 The pulsed laser after the first loop optical path LOP1 not shown in the figure is reflected and incident on the high reflection mirror 124b. The high reflection mirror 124b is configured so that the pulsed laser after being reflected by the high reflection mirror 124a is reflected and incident on the high reflection mirror 124c. The high reflection mirror 124c is configured so that the pulsed laser after being reflected by the high reflection mirror 124b is reflected and incident on the high reflection mirror 124d. The high reflection mirror 124d is configured so that the pulsed laser after being reflected by the high reflection mirror 124c is reflected and incident on Figure 7 The second beam splitter BS2 not shown in the figure. The angle between the incident light and the reflected light of each of the high reflective mirrors 124a, 124b, 124c and 124d (the sum of the incident angle and the reflection angle) may be, for example, 90 degrees.

[0174] The beam rotation mechanism 123 is an example of the “first beam rotation mechanism” in the present disclosure. The high-reflection mirrors 124a, 124b, 124c, and 124d are examples of “four or more mirrors” constituting the “first beam rotation mechanism” in the present disclosure.

[0175] 4.2 Action

[0176] The pulse laser beam incident on the high reflection mirror 124 a is reflected by the high reflection mirrors 124 a , 124 b , 124 c , and 124 d in this order and then incident on the second beam splitter BS2 .

[0177] The beam rotation mechanism 123 and Figure 4 Compared with the beam rotation mechanism 120, the number of high-reflection mirrors is increased to propagate the pulse laser in a manner that does not interfere with other devices not shown in the figure, and the beam rotation mechanism 123 rotates the pulse laser so that the short side direction of the beam cross section of the pulse laser in the second circulating optical path LOP2 is parallel to the circulating optical path plane.

[0178] 4.3 Effects

[0179] By adopting the beam rotation mechanism 123 of Modification 1, it is possible to realize an appropriate mirror arrangement corresponding to the surrounding space.

[0180] Furthermore, according to the beam rotation mechanism 123 of variation 1, the pulse laser can be propagated without interfering with other devices, and the delay path can be expanded so that the short side direction of the beam cross section of the pulse laser in the second loop optical path LOP2 is parallel to the loop optical path plane.

[0181] 5. Modification 2 of the beam rotation mechanism

[0182] 5.1 Structure

[0183] Figure 8A second modification of the beam rotation mechanism 120 is shown. Figure 4 and Figure 5 The beam rotation mechanism 120 shown is used Figure 8 The beam rotation mechanism 125 shown in the figure may be composed of four high reflection mirrors 126a, 126b, 126c and 126d.

[0184] The angle between the incident light and the reflected light of the mirror constituting the beam rotation mechanism 125 may be other than 90 degrees. For example, the angle between the incident light and the reflected light of the high reflector 126b and the angle between the incident light and the reflected light of the high reflector 126c may be 45 degrees respectively.

[0185] The high reflective mirror 126a is configured to Figure 8 The pulsed laser after the first loop optical path LOP1 not shown in the figure is reflected and incident on the high reflection mirror 126b. The high reflection mirror 126b is configured so that the pulsed laser emitted from the high reflection mirror 126a is reflected at a reflection angle of 45 degrees and incident on the high reflection mirror 126c. The high reflection mirror 126c is configured so that the pulsed laser emitted from the high reflection mirror 126b is reflected at a reflection angle of 45 degrees and incident on the high reflection mirror 126d. The high reflection mirror 126d is configured so that the pulsed laser emitted from the high reflection mirror 126c is reflected and incident on Figure 8 The second beam splitter BS2 not shown in the figure.

[0186] The beam rotation mechanism 125 is an example of the “first beam rotation mechanism” in the present disclosure. The high-reflection mirrors 126a, 126b, 126c, and 126d are examples of “four or more mirrors” constituting the “first beam rotation mechanism” in the present disclosure.

[0187] 5.2 Action

[0188] The pulse laser beam incident on the high reflection mirror 126 a is reflected by the high reflection mirrors 126 a , 126 b , 126 c , and 126 d in this order and then incident on the second beam splitter BS2 .

[0189] The beam rotation mechanism 125 and Figure 4 Compared with the beam rotation mechanism 120, the number of high-reflection mirrors is increased to propagate the pulse laser in a manner that does not interfere with other devices not shown in the figure, and the beam rotation mechanism 125 rotates the pulse laser so that the short side direction of the beam cross section of the pulse laser in the second circulating optical path LOP2 is parallel to the circulating optical path plane.

[0190] 5.3 Effects

[0191] The beam rotation mechanism 125 of Modification 2 can also realize an appropriate mirror configuration corresponding to the surrounding space, similar to Modification 1. In addition, according to the beam rotation mechanism 125 of Modification 2, the pulse laser can be propagated in a manner that does not interfere with other devices, and the delay optical path can be expanded in a manner that the short side direction of the beam cross section of the pulse laser in the second loop optical path LOP2 is parallel to the loop optical path plane.

[0192] 6. Implementation Method 3

[0193] 6.1 Structure

[0194] Fig. 9 is a plan view schematically showing the structure of a laser device 2B according to Embodiment 3. Fig.10 2B is a front view schematically showing the structure of the laser device 2B. Figure 2 and Figure 3 The differences in the structures shown are explained below.

[0195] The laser device 2B of the third embodiment is configured by exchanging the order in which the pulse laser light of the first embodiment passes through the first circulation optical path LOP1 and the second circulation optical path LOP2 of the L-OPS 100 disposed on the back side of the laser device 2A.

[0196] Detailed structure of L-OPS100C which is arranged on the back side of laser device 2B instead of L-OPS100 Fig.11 This will be described later.

[0197] In the L-OPS 100C, a structure is adopted in which the order of passing through the first loop optical path LOP1 and the second loop optical path LOP2 in the L-OPS 100 is reversed, and thus the longitudinal direction and the short side direction of the beam cross section of the pulse laser incident on the L-OPS 100C and the pulse laser emitted from the L-OPS 100C are different from those of the L-OPS 100. Therefore, the laser device 2B has a PO beam steering unit 45 having a structure different from that of the PO beam steering unit 40.

[0198] The PO beam steering unit 45 includes a high reflection mirror 46a, a high reflection mirror 46b, a high reflection mirror 46c, a high reflection mirror 46d, and a high reflection mirror 46e to exchange light with the L-OPS100C.

[0199] The high reflector 46a is configured to reflect the pulse laser output from the power oscillator 30 and make it incident on the high reflector 46b. The high reflector 46b is configured to reflect the pulse laser emitted from the high reflector 46a and make it incident on the high reflector 46c. The high reflector 46c is configured to reflect the pulse laser emitted from the high reflector 46b and make it incident on the L-OPS100C. The high reflector 46d is configured to reflect the pulse laser emitted from the L-OPS100C and make it incident on the high reflector 46e. The high reflector 46e is configured to make the pulse laser emitted from the high reflector 46d incident on the OPS50.

[0200] 6.2 Action

[0201] The PO beam steering unit 45 adjusts the longitudinal and short-side directions of the beam cross section of the pulse laser emitted from the power oscillator 30 through the high-reflection mirrors 46a, 46b, and 46c, and emits the pulse laser toward the L-OPS 100C. That is, the pulse laser emitted from the power oscillator 30 is reflected by the high-reflection mirrors 46a, 46b, and 46c in this order and enters the L-OPS 100C.

[0202] The return light (expanded pulse laser) whose pulse width is expanded by L-OPS100C and emitted from L-OPS100C toward the PO beam steering unit 45 is emitted toward OPS50 after the directions of the longitudinal direction and the short side direction of the beam cross section are adjusted by the high reflection mirrors 46d and 46e.

[0203] 6.3 Specific example of L-OPS

[0204] 6.3.1 Structure

[0205] Fig.11 This is a perspective view schematically showing the structure of L-OPS100C according to Embodiment 3. Fig.11 The structure shown is Figure 4 The differences in the structures shown are explained below.

[0206] replace Figure 4 The beam rotation mechanism 43 is provided with high reflection mirrors 46a, 46b and 46c, and the pulse laser from the power oscillator 30 is reflected by the high reflection mirrors 46a, 46b and 46c, thereby allowing the pulse laser to be incident on the L-OPS100C.

[0207] In addition, you can also omit Fig.11 The high reflection mirrors 46a and 46b shown in the figure allow the pulse laser from the power oscillator 30 to be incident on the L-OPS 100C using a single high reflection mirror 46c.

[0208] L-OPS100C Replacement Figure 4The beam rotation mechanism 120 is replaced with only the high reflection mirror 128. The high reflection mirror 128 is arranged so as to reflect the pulse laser light emitted from the high reflection mirror 46c and make it incident on the second beam splitter BS2.

[0209] The high reflector 141 and the high reflector 142 constitute a return optical path FOP for guiding the pulsed laser after passing through the second loop optical path LOP2 to the first loop optical path LOP1. The high reflector 141 and the high reflector 142 are an example of a "return propagation optical system" in the present disclosure, and the return optical path FOP is an example of an "optical path formed in the return propagation optical system" in the present disclosure.

[0210] In addition, L-OPS100C replaces Figure 4 In addition to the high reflection mirror 143 , a beam rotation mechanism 157 composed of a high reflection mirror 153 and a high reflection mirror 154 is provided.

[0211] The second beam splitter BS2 is disposed between the high reflection mirror 128 and the high reflection mirror 141. Alternatively, the second beam splitter BS2 may be disposed on the optical path between the high reflection mirror 142 and the high reflection mirror 153.

[0212] The mirrors are arranged so that the second circulation optical path LOP2 and the propagation optical path of the pulse laser light constituted by the high reflection mirror 128 , the high reflection mirror 141 , the high reflection mirror 142 , the high reflection mirror 153 , and the high reflection mirror 154 are in the same plane.

[0213] The first beam splitter BS1 is arranged on the optical path between the high reflection mirror 154 and the high reflection mirror 46 d .

[0214] In addition, instead of Figure 4 In addition to the high reflection mirror 44c, a beam rotation mechanism 47 composed of a high reflection mirror 46d and a high reflection mirror 46e is provided.

[0215] 6.3.2 Action

[0216] The pulse laser light emitted from the power oscillator 30 enters the high reflection mirror 128 via the high reflection mirrors 46 a , 46 b , and 46 c , is reflected by the high reflection mirror 128 , and enters the second beam splitter BS2 .

[0217] The length direction of the beam cross section of the pulsed laser incident on the high reflector 46a is oriented in the V-axis direction. The length direction of the beam cross section of the pulsed laser reflected by the high reflectors 46a, 46b, and 46c and emitted from the high reflector 46c is oriented in the V-axis direction. That is, the high reflectors 46a to 46c propagate the pulsed laser without rotating the beam (in a non-rotating manner).

[0218] Regarding the beam propagated by the high reflection mirrors 46a, 46b, and 46c without rotation, the longitudinal direction of the beam cross section of the pulsed laser light in the second circulation optical path LOP2 is oriented in a direction orthogonal to the second circulation optical path plane.

[0219] The pulsed laser beam propagated by the high reflection mirrors 46a, 46b, 46c and the high reflection mirror 128 is incident on the first surface of the second beam splitter BS2, and the pulsed laser beam reflected by the first surface of the second beam splitter BS2 propagates in the second circulating optical path LOP2. The pulsed laser beam that has passed through the first surface of the second beam splitter BS2 and the pulsed laser beam that has propagated in the second circulating optical path LOP2 and reflected by the second surface of the second beam splitter BS2 are reflected by the high reflection mirrors 141 and 142, and then are incident on the beam rotation mechanism 157.

[0220] The beam rotation mechanism 157 rotates the pulsed laser light so that the longitudinal direction of the beam cross section of the pulsed laser light is orthogonal to the first circulation optical path plane in the first circulation optical path LOP1.

[0221] The pulse laser emitted from the high reflection mirror 154 of the beam rotation mechanism 157 is incident on the first beam splitter BS1. The pulse laser reflected by the first beam splitter BS1 propagates in the first circulation optical path LOP1. The pulse laser (circulation light) reflected by the first beam splitter BS1 after circulating in the first circulation optical path LOP1 and the pulse laser (passing light) not circulating in the first circulation optical path LOP1 but passing through the first beam splitter BS1 are incident on the beam rotation mechanism 47.

[0222] The pulse laser incident on the high reflection mirror 46d is reflected by the high reflection mirror 46d and the high reflection mirror 46e. The high reflection mirror 46d and the high reflection mirror 46e rotate the beam so that the length direction of the beam cross section of the pulse laser emitted from the high reflection mirror 46e is oriented toward the V-axis direction. The pulse laser reflected by the high reflection mirror 46e is incident on the OPS50.

[0223] Fig.11 The second optical loop LOP2 shown is an example of the "first optical loop" in the present disclosure. Fig.11 The first optical path LOP1 shown is an example of the "second optical path" in the present disclosure. Fig.11 The second beam splitter BS2 shown is an example of the "first beam splitter" in the present disclosure. Fig.11 The first beam splitter BS1 shown is an example of the “second beam splitter” in the present disclosure. Fig.11 The concave mirrors 131 to 134 shown are examples of the "first concave mirror" in the present disclosure. Fig.11 The concave mirrors 111 to 116 shown are examples of the "second concave mirror" in the present disclosure, respectively. The beam rotation mechanism 157 is an example of the "first beam rotation mechanism" in the present disclosure.

[0224] 6.4 Effects

[0225] According to the L-OPS 100C of the third embodiment and the laser device 2B including the L-OPS 100C, the same operation and effect as those of the first embodiment can be obtained. In addition, according to the structure of the third embodiment, the degree of freedom of appropriate arrangement corresponding to the surrounding space is increased.

[0226] 6.5 Variations

[0227] Can also replace Fig.11 The concave mirrors 111 to 116 constituting the first circulating optical path LOP1 are used. Figure 5 Concave mirrors 111 to 118 constituting the first circulation optical path LOP1B described in the drawings.

[0228] 7. About the manufacturing method of electronic devices

[0229] Fig.12 The structure example of the exposure device 80 is schematically shown. The exposure device 80 includes an illumination optical system 804 and a projection optical system 806. The illumination optical system 804 illuminates the mask pattern of the mask (not shown) arranged on the mask stage RT by the laser light incident from the laser device 2A. The projection optical system 806 performs reduced projection of the laser light transmitted through the mask so as to form an image on the workpiece (not shown) arranged on the workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a photoresist.

[0230] The exposure device 80 moves the mask stage RT and the work stage WT synchronously and in parallel, thereby exposing the workpiece to the laser reflecting the mask pattern. After the mask pattern is transferred to the semiconductor wafer through the above exposure process, a semiconductor device can be manufactured through multiple processes. The semiconductor device is an example of an "electronic device" in the present disclosure. It is not limited to the laser device 2A, and the laser device 2B and the like can also be used.

[0231] 8. Others

[0232] The above description is not limiting but simply illustrative. Therefore, those skilled in the art will appreciate that changes can be made to the embodiments of the present disclosure without departing from the claims. In addition, those skilled in the art will appreciate that the embodiments of the present disclosure can be used in combination.

[0233] Unless explicitly stated otherwise, the terms used in this specification and claims as a whole should be interpreted as "non-limiting" terms. For example, terms such as "including", "having", "having", and "having" should be interpreted as "excluding the existence of structural elements other than the structural elements to be recorded". In addition, the modifier "one" should be interpreted as meaning "at least one" or "one or more". In addition, terms such as "at least one of A, B, and C" should be interpreted as "A", "B", "C", "A+B", "A+C", "B+C", or "A+B+C". Furthermore, it should be interpreted as also including combinations of them and parts other than "A", "B", and "C".

Claims

1. A pulse width extension device, comprising: a first delay optical system comprising a first beam splitter and a plurality of first concave mirrors, wherein a first circulating optical path constituted by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system comprising a second beam splitter and a plurality of second concave mirrors, wherein a second circulating optical path constituted by the second beam splitter and the plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the longitudinal direction of the cross-sectional shape of the beam of the pulsed laser traveling in the second circulating optical path is orthogonal to the second plane; The pulse width expansion device further includes a return propagation optical system for propagating the pulse laser light after passing through the second delay optical system. The optical path formed in the return propagation optical system is formed on a plane that is coplanar with the second plane.

2. The pulse width extension device according to claim 1, wherein: The return propagation optical system is composed of a plurality of mirrors.

3. The pulse width extension device according to claim 1, wherein: A second beam rotation mechanism is further provided in the preceding stage of the first delay optical system. The second beam rotation mechanism rotates the beam of pulsed laser light incident on the first delay optical system so that the longitudinal direction of the beam cross-sectional shape of the pulsed laser light traveling in the first circulation optical path is orthogonal to the first plane.

4. The pulse width extension device according to claim 3, wherein: The second beam rotation mechanism includes two or more mirrors.

5. The pulse width extension device according to claim 1, wherein: The first delay optical system includes four or more first concave mirrors.

6. The pulse width extension device according to claim 1, wherein: The first delay optical system is configured with a pair of the first concave mirrors arranged in an even number facing each other.

7. The pulse width extension device according to claim 1, wherein: The second delay optical system includes four or more second concave mirrors.

8. The pulse width extension device according to claim 1, wherein: The second delay optical system is configured with a pair of the second concave mirrors arranged in an even number facing each other.

9. The pulse width extension device according to claim 1, wherein: The pulse width extending device is arranged on the back side of the laser device that outputs the pulse laser.

10. The pulse width extension device according to claim 1, wherein: The first plane is parallel to the direction of gravity.

11. The pulse width extension device according to claim 1, wherein: Let n and m be integers greater than 2, The first delay optical system includes 2n first concave mirrors. The second delay optical system includes 2m second concave mirrors. When a direction perpendicular to the first plane is defined as a first axis direction, and two directions perpendicular to the first axis direction and perpendicular to each other are defined as a second axis direction and a third axis direction, Regarding the 2n first concave mirrors, each row of n first concave mirrors is arranged facing each other in the second axis direction, and in each row of the first concave mirrors on one side, n first concave mirrors are arranged side by side in the third axis direction. Regarding the 2m second concave mirrors, each row of m second concave mirrors is arranged facing each other in the second axis direction, and in each single-side row of the second concave mirrors, m second concave mirrors are arranged side by side in the third axis direction.

12. The pulse width extension device according to claim 11, wherein: The pulse laser is incident on the first beam splitter from the first axis direction.

13. The pulse width extension device according to claim 11, wherein: The pulse laser is incident on the first beam splitter from the third axis direction.

14. A pulse width extension device, comprising: a first delay optical system comprising a first beam splitter and a plurality of first concave mirrors, wherein a first circulating optical path constituted by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system comprising a second beam splitter and a plurality of second concave mirrors, wherein a second circulating optical path constituted by the second beam splitter and the plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the longitudinal direction of the cross-sectional shape of the beam of the pulsed laser traveling in the second circulating optical path is orthogonal to the second plane; The first beam rotation mechanism includes two or more mirrors.

15. A pulse width extension device, comprising: a first delay optical system comprising a first beam splitter and a plurality of first concave mirrors, wherein a first circulating optical path constituted by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system comprising a second beam splitter and a plurality of second concave mirrors, wherein a second circulating optical path constituted by the second beam splitter and the plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the longitudinal direction of the cross-sectional shape of the beam of the pulsed laser traveling in the second circulating optical path is orthogonal to the second plane; The first beam rotation mechanism includes four or more mirrors.

16. The pulse width extension device according to claim 15, wherein: An angle between incident light and reflected light of at least one mirror among the four or more mirrors constituting the first beam rotation mechanism is 45 degrees.

17. A pulse width extension device, comprising: a first delay optical system comprising a first beam splitter and a plurality of first concave mirrors, wherein a first circulating optical path constituted by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system comprising a second beam splitter and a plurality of second concave mirrors, wherein a second circulating optical path constituted by the second beam splitter and the plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the longitudinal direction of the cross-sectional shape of the beam of the pulsed laser traveling in the second circulating optical path is orthogonal to the second plane; A return propagation optical system is further provided on the optical path between the first beam splitter and the first beam rotation mechanism, and the return propagation optical system propagates the pulse laser light after passing through the first delay optical system. The optical path formed in the return propagation optical system is formed on a plane that is coplanar with the first plane.

18. A laser device comprising: a laser oscillator that outputs pulsed laser light; and A pulse width expansion device is arranged on the optical path of the pulse laser. in, The pulse width extension device comprises: a first delay optical system comprising a first beam splitter and a plurality of first concave mirrors, wherein a first circulating optical path constituted by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system comprising a second beam splitter and a plurality of second concave mirrors, wherein a second circulating optical path formed by the second beam splitter and the plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; as well as a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the longitudinal direction of the cross-sectional shape of the beam of the pulsed laser traveling in the second circulating optical path is orthogonal to the second plane; The pulse width expansion device further includes a return propagation optical system for propagating the pulse laser light after passing through the second delay optical system. The optical path formed in the return propagation optical system is formed on a plane that is coplanar with the second plane.

19. A method for manufacturing an electronic device, comprising the following steps: generating laser light with a pulse width extended by a 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 laser device has: a first delay optical system comprising a first beam splitter and a plurality of first concave mirrors, wherein a first circulating optical path constituted by the first beam splitter and the plurality of first concave mirrors is formed on a first plane; a second delay optical system comprising a second beam splitter and a plurality of second concave mirrors, wherein a second circulating optical path constituted by the second beam splitter and the plurality of second concave mirrors is formed on a second plane parallel to the first plane and different from the first plane; and a first beam rotation mechanism, which is arranged on the optical path between the first delay optical system and the second delay optical system, and rotates the beam of the pulsed laser after passing through the first delay optical system so that the longitudinal direction of the cross-sectional shape of the beam of the pulsed laser traveling in the second circulating optical path is orthogonal to the second plane; The laser device further includes a return propagation optical system for propagating the pulsed laser light after passing through the second delay optical system. The optical path formed in the return propagation optical system is formed on a plane that is coplanar with the second plane.

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