Laser system and method for manufacturing electronic device

Abstract

A laser system and a method of manufacturing an electronic device are provided. A laser system is provided with: a first pulse laser device that emits first pulse laser light at a predetermined period; a second pulse laser device that emits a second pulse laser at a predetermined period; a first polygon mirror that reflects the first pulse laser light and the second pulse laser light; and a processor that controls the first pulse laser device, the second pulse laser device, and the first polygon mirror such that the first pulse laser beam and the second pulse laser beam are emitted while being shifted by half of a prescribed period. The optical paths of the first pulse laser beam and the second pulse laser beam reflected by the first polygon mirror face the first direction and at least partially coincide with each other.

Description

Technical Field

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

[0002] In recent years, semiconductor exposure equipment has been required to achieve higher resolution as semiconductor integrated circuits become increasingly miniaturized and highly integrated. Consequently, there has been a trend toward shorter wavelengths of light emitted from exposure light sources. For example, gas laser devices used for exposure include KrF excimer lasers, which output laser light with a wavelength of approximately 248 nm, and ArF excimer lasers, which output laser light with a wavelength of approximately 193 nm.

[0003] The spectral line width of the natural oscillation light of the KrF excimer laser device and the ArF excimer laser device is as wide as 350pm to 400pm. Therefore, if the projection lens is made of a material that transmits ultraviolet rays such as KrF and ArF lasers, chromatic aberration may sometimes occur. As a result, the resolution may be reduced. Therefore, it is necessary to narrow the spectral line width of the laser 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 Narrowing 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 with a narrowed spectral line width is referred to as a narrowed gas laser device.

[0004] Prior art literature

[0005] Patent Literature

[0006] [Patent Document 1] U.S. Patent Application Publication No. 2023004091

[0007] [Patent Document 2] Chinese Utility Model No. 219143208

[0008] [Patent Document 3] U.S. Patent No. 5,387,211 Summary of the Invention

[0009] A laser system according to one embodiment of the present invention may include: a first pulse laser device that emits a first pulse laser at a prescribed period; a second pulse laser device that emits a second pulse laser at a prescribed period; a first polygonal mirror that reflects the first pulse laser and the second pulse laser; and a processor that controls the first pulse laser device, the second pulse laser device, and the first polygonal mirror so that the first pulse laser and the second pulse laser are emitted with a gap of half the prescribed period, and so that the optical paths of the first pulse laser and the second pulse laser after being reflected by the first polygonal mirror are directed in a first direction and at least partially overlap.

[0010] In addition, a method for manufacturing an electronic device according to one embodiment of the present invention may also include the following steps: outputting a first pulse laser and a second pulse laser generated by a laser system to an exposure device; and exposing the first pulse laser and the second pulse laser on a photosensitive substrate in the exposure device to manufacture the electronic device, the laser system including: a first pulse laser device that emits a first pulse laser at a prescribed period; a second pulse laser device that emits a second pulse laser at a prescribed period; a first polygonal mirror that reflects the first pulse laser and the second pulse laser; and a processor that controls the first pulse laser device, the second pulse laser device and the first polygonal mirror so that the first pulse laser and the second pulse laser are emitted with a gap of half the prescribed period, and so that the optical paths of the first pulse laser and the second pulse laser after being reflected by the first polygonal mirror are directed in a first direction and at least partially overlap. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0012] Figure 1 This is a schematic diagram showing an example of the overall schematic configuration of an electronic device manufacturing apparatus.

[0013] Figure 2 It is a schematic diagram showing an overall schematic configuration example of a laser system according to a comparative example.

[0014] Figure 3 It is a schematic diagram showing a schematic configuration example of a pulse laser device included in a laser system of a comparative example.

[0015] Figure 4 It is a timing chart showing the relationship between the emission timing of the first pulse laser light and the emission timing of the second pulse laser light.

[0016] Figure 5 1 is a timing chart showing emission timing of pulse coupled light obtained by combining the first pulse laser light and the second pulse laser light.

[0017] Figure 6 This is a schematic diagram showing an example of a schematic configuration of a laser system according to the first embodiment.

[0018] Figure 7 It is a schematic diagram showing a schematic configuration example of a beam steering device.

[0019] Figure 8 This is a schematic diagram showing a schematic configuration example of a beam measuring device.

[0020] Figure 9 This is a schematic diagram showing a schematic configuration example of a laser system in a modified example of the first embodiment.

[0021] Figure 10This is a schematic diagram showing an example of a schematic configuration of a laser system according to a second embodiment.

[0022] Figure 11 It is a timing chart showing the relationship between the emission timings of the first to fourth pulsed laser beams.

[0023] Figure 12 This is a timing chart showing the relationship between the emission timings of pulse coupled light obtained by combining the first pulse laser light and the second pulse laser light and pulse coupled light obtained by combining the third pulse laser light and the fourth pulse laser light.

[0024] Figure 13 It is a timing chart showing the emission timing of pulse coupled light obtained by combining the first to fourth pulse laser lights.

[0025] Figure 14 This is a schematic diagram showing a schematic configuration example of a laser system in a modified example of the second embodiment. DETAILED DESCRIPTION

[0026] 1. Description of the electronic device manufacturing apparatus used in the exposure process of the electronic device

[0027] 2. Description of the Laser System of the Comparative Example

[0028] 2.1 Structure

[0029] 2.2 Action

[0030] 2.3 Topics

[0031] 3. Description of the Laser System of Embodiment 1

[0032] 3.1 Structure

[0033] 3.2 Action

[0034] 3.3 Function and effect

[0035] 3.4 Variations

[0036] 4. Description of the Laser System of Implementation Method 2

[0037] 4.1 Structure

[0038] 4.2 Action

[0039] 4.3 Function and effect

[0040] 4.4 Variations

[0041] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, not all of the structures and actions described in each embodiment are necessarily required as the structures and actions of the present disclosure. In addition, the same reference numerals are attached to the same components, and repeated descriptions are omitted.

[0042] 1. Description of the electronic device manufacturing apparatus used in the exposure process of the electronic device

[0043] Figure 1 Schematic diagram showing an overall schematic configuration example of an electronic device manufacturing apparatus used in an exposure process of an electronic device. Figure 1 As shown, the manufacturing device used in the exposure process includes a laser system 100 and an exposure device 200. The exposure device 200 includes an illumination optical system 210 having a plurality of mirrors 211, 212, and 213, and a projection optical system 220. The illumination optical system 210 uses the laser light incident from the laser system 100 to illuminate the mask pattern on the mask carrier RT. The projection optical system 220 performs a reduced projection of the laser light transmitted through the mask so that it is imaged on a workpiece (not shown) arranged on the workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a photoresist. The exposure device 200 exposes the workpiece with the laser light reflecting the mask pattern by moving the mask carrier RT and the workpiece stage WT in parallel in synchronization. By transferring the device pattern to the semiconductor wafer using the above-mentioned exposure process, a semiconductor device as an electronic device can be manufactured.

[0044] 2. Description of the Laser System of the Comparative Example

[0045] 2.1 Structure

[0046] The laser system of the comparative example will be described. Note that the comparative examples disclosed herein are methods that the applicant has recognized as being known only to the applicant, and are not examples that the applicant considers to be publicly known.

[0047] Figure 2 This is a schematic diagram showing an example of the overall schematic configuration of the laser system 100 of this example. The laser system 100 includes a first pulsed laser device 120a and a second pulsed laser device 120b. The first pulsed laser device 120a and the second pulsed laser device 120b have identical configurations, each including a laser oscillator 130 as a master oscillator and an amplifier 160 as a power oscillator. Furthermore, the first pulsed laser device 120a and the second pulsed laser device 120b emit pulsed laser light L1 and L2 of a predetermined period.

[0048] The first pulsed laser device 120a and the second pulsed laser device 120b are, for example, ArF excimer laser devices that use a mixed gas containing argon (Ar), fluorine (F2), and neon (Ne). The ArF excimer laser device emits laser light with a central wavelength of approximately 193.4 nm. Alternatively, the first pulsed laser device 120a and the second pulsed laser device 120b may be, for example, KrF excimer laser devices that use a mixed gas containing krypton (Kr), F2, and Ne. The KrF excimer laser device emits laser light with a central wavelength of approximately 248.3 nm.

[0049] In addition, the laser system 100 also has: a beam combiner 150, which guides the first pulse laser L1 and the second pulse laser L2 to the same optical path; and reflectors 170a, 170b, which reflect the first pulse laser L1 from the first pulse laser device 120a and the second pulse laser L2 from the second pulse laser device 120b toward the beam combiner 150.

[0050] The beam combiner 150 emits the first pulse laser L1 and the second pulse laser L2 incident via the reflection mirrors 170a and 170b along the same optical path. The beam combiner 150 can perform spatial beam coupling and polarization beam coupling between the first pulse laser L1 and the second pulse laser L2.

[0051] The processor 105 is a processing device that includes a storage device that stores a control program and a CPU (Central Processing Unit) that executes the control program. The processor 105 is specially configured or programmed to perform the various processes included in the present disclosure. The first and second pulsed laser devices 120a and 120b are controlled by the processor 105, and the processor 105 causes the first and second pulsed lasers L1 and L2 to be emitted at a frequency that is offset by half of a specified period. Therefore, the first and second pulsed lasers L1 and L2 are emitted alternately. The optical paths of the first and second pulsed lasers L1 and L2 are overlapped by the beam combiner 150, and the pulsed lasers are emitted from the laser system 100 at a repetition frequency that is twice that of a single pulsed laser device.

[0052] In this specification, the laser beams in which at least a portion of the optical paths of the pulsed laser beams from a plurality of pulsed laser devices overlap and each pulsed laser beam travels in the same direction are referred to as pulse coupled light. Therefore, the pulsed laser beams composed of the first pulsed laser beam L1 and the second pulsed laser beam L2 emitted from the beam combiner 150 are pulse coupled light beams L1 and L2. 12 .

[0053] Next, the first pulse laser device 120a and the second pulse laser device 120b having the same structure are used as the pulse laser device 120, and the structures thereof are as follows. Figure 3The pulse laser device 120 mainly includes a housing 110, a master oscillator (ie, laser oscillator 130) disposed in the interior space of the housing 110, an optical transmission unit 141, a power oscillator (ie, amplifier 160), a detection unit 153, a display unit 180, and a processor 190.

[0054] The laser oscillator 130 includes a chamber device CH1 , a charger 41 , a pulse power module 43 , a band-narrowing module 60 , and an output coupling mirror 70 as main components.

[0055] exist Figure 3 , the internal structure of chamber device CH1 as viewed from a direction substantially perpendicular to the propagation direction of the laser light is shown. Chamber device CH1 mainly includes a housing 30, a pair of windows 31a, 31b, a pair of electrodes 32a, 32b, an insulating portion 33, a feedthrough 34, and an electrode holder 36.

[0056] The housing 30 has laser gas sealed in its internal space. The internal space is a space where light is generated by excitation of the laser medium in the laser gas. This light propagates to the windows 31a and 31b.

[0057] Window 31a is located on the front wall of housing 30 in the direction of laser light propagation from laser system 100 toward exposure device 200, and window 31b is located on the rear wall of housing 30 in the same direction of laser light propagation. Windows 31a and 31b are formed, for example, from a calcium fluoride substrate, with the surfaces of windows 31a and 31b located on the interior and exterior sides of housing 30 being flat. Windows 31a and 31b may be made of any material other than a calcium fluoride substrate, as long as they can transmit laser light.

[0058] Electrodes 32a and 32b are positioned opposite each other within the interior of housing 30, with their lengths oriented along the propagation direction of light generated by the high voltage applied between electrodes 32a and 32b. The discharge space between electrodes 32a and 32b in housing 30 is bounded by windows 31a and 31b. Electrodes 32a and 32b serve as discharge electrodes for exciting the laser medium through glow discharge. In this example, electrode 32a serves as the cathode, and electrode 32b serves as the anode.

[0059] Electrode 32a is supported by an insulating portion 33. The insulating portion 33 closes the opening formed in the housing 30. The insulating portion 33 comprises an insulator. Furthermore, a feedthrough 34 formed of a conductive member is disposed within the insulating portion 33. The feedthrough 34 applies the voltage supplied from the pulse power module 43 to the electrode 32a. The electrode 32b is supported by and electrically connected to the electrode holder 36.

[0060] The charger 41 is a DC power supply device that charges a capacitor (not shown) provided inside the pulse power module 43 at a predetermined voltage. The charger 41 is located outside the housing 30 and is connected to the pulse power module 43. The pulse power module 43 includes a switch (not shown) controlled by the processor 190. The pulse power module 43 is a voltage application circuit that, when the switch is switched from off to on by this control, boosts the voltage applied from the charger 41 to generate a pulsed high voltage, which is then applied to the electrodes 32a and 32b. When the high voltage is applied, a discharge occurs between the electrodes 32a and 32b. The energy from this discharge excites the laser medium within the housing 30. When the excited laser gas transitions to the ground state energy level, light is emitted, which is then emitted through the windows 31a and 31b and emitted to the outside of the housing 30. Windows 31a and 31b are tilted at a Brewster's angle with the laser beam's propagation direction to suppress reflection of the laser beam's p-polarized light. In this example, they are tilted perpendicular to the laser beam's propagation direction and the direction in which electrodes 32a and 32b face each other. Consequently, the laser beam emitted from chamber device CH1 contains a predetermined linearly polarized light with a polarization direction perpendicular to the direction in which electrodes 32a and 32b face each other, while linearly polarized light with a polarization direction different from the predetermined linearly polarized light is reduced from the laser beam.

[0061] The narrowband module 60 includes a housing 65, a prism 61, a grating 63, and a rotating stage (not shown) disposed in the interior of the housing 65. The housing 65 has an opening, and the housing 65 is connected to the rear side of the housing 30 via the opening.

[0062] The prism 61 expands the beam width of the light emitted from the window 31b and causes the light to enter the grating 63. In addition, the prism 61 reduces the beam width of the reflected light from the grating 63 and causes the light to return to the internal space of the housing 30 through the window 31b. The prism 61 is supported on a rotating stage and rotates by the rotating stage. The rotation of the prism 61 changes the incident angle of the light entering the grating 63, and the wavelength of the light returned from the grating 63 through the prism 61 to the housing 30 can be selected. Figure 3 , an example in which one prism 61 is arranged is shown, but two or more prisms may be arranged.

[0063] The surface of the grating 63 is made of a high-reflectivity material and has a plurality of grooves arranged at predetermined intervals. The grating 63 is a dispersive optical element. The cross-sectional shape of each groove is, for example, a right triangle. Light incident on the grating 63 from the prism 61 is reflected by these grooves and diffracted in a direction corresponding to the wavelength of the light. The grating 63 is configured by Littrow so that the angle of incidence of the light incident on the grating 63 from the prism 61 coincides with the diffraction angle of the diffracted light of the desired wavelength. As a result, the light of the desired wavelength is returned to the housing 30 via the prism 61.

[0064] The output coupling mirror 70 transmits part of the laser light emitted from the window 31a and reflects the other part to return it to the interior of the housing 30 through the window 31a. The output coupling mirror 70 is fixed to a holding portion (not shown) and is disposed in the interior of the housing 110.

[0065] The grating 63 and the output coupling mirror 70 provided via the housing 30 constitute a Fabry-Perot type resonator. The housing 30 is arranged on the optical path of the resonator.

[0066] The optical transmission unit 141 includes high-reflection mirrors 141b and 141c as its main components. High-reflection mirrors 141b and 141c are fixed to respective retaining portions (not shown) with their respective tilt angles adjusted, and are located within the interior space of the housing 110. High-reflection mirrors 141b and 141c provide high-reflectivity for laser light. High-reflection mirrors 141b and 141c are located on the optical path of laser light that passes through the output coupling mirror 70. This laser light is reflected by high-reflection mirrors 141b and 141c and propagates to the rear mirror 371 of the amplifier 160. At least a portion of this laser light passes through the rear mirror 371.

[0067] The amplifier 160 amplifies the energy of the laser light output from the laser oscillator 130. The basic structure of the amplifier 160 is substantially the same as that of the laser oscillator 130. Therefore, the same reference numerals are given to the same structures as those of the laser oscillator 130, and detailed descriptions are omitted unless otherwise specified. The electrodes 32a and 32b generate discharges for amplifying the laser light from the laser oscillator 130. The direction in which the electrodes 32a and 32b face each other is perpendicular to the polarization direction of the linearly polarized light in the laser light from the laser oscillator 130. The windows 31a and 31b are tilted relative to the polarization direction of the prescribed linearly polarized light so that the linearly polarized light in the laser light is incident as P-polarized light and the incident angle of the laser light becomes the Brewster angle. Therefore, the laser light emitted from the chamber device CH2 contains the prescribed linearly polarized light, and linearly polarized light having a polarization direction different from the polarization direction of the prescribed linearly polarized light is reduced from the laser light.

[0068] Furthermore, the amplifier 160 differs from the laser oscillator 130 in that it does not include the bandwidth narrowing module 60 but includes a rear mirror 371. The rear mirror 371 is disposed between the high-reflection mirror 141c and the window 31b. The rear mirror 371 transmits a portion of the laser light from the laser oscillator 130 toward the discharge space between the electrodes 32a and 32b, and reflects a portion of the laser light amplified in the chamber device CH2 back toward the discharge space of the chamber device CH2.

[0069] The output coupling mirror 370 is located on the side of the chamber device CH2 opposite the rear mirror 371. The output coupling mirror 370 reflects a portion of the laser light from the chamber device CH2 and transmits another portion of the laser light. Therefore, a partially reflective film having a predetermined reflectivity is applied to the surface of the output coupling mirror 370 located on the chamber device CH2 side.

[0070] The detection section 153 includes a beam splitter 153 b and a photosensor 153 c as main structures.

[0071] The beam splitter 153b is disposed on the optical path of the laser beam transmitted through the output coupling mirror 370. The beam splitter 153b transmits the laser beam transmitted through the output coupling mirror 370 with high transmittance toward the emission window 173 and reflects a portion of the laser beam toward the light receiving surface of the optical sensor 153c.

[0072] Optical sensor 153c measures the pulse energy of the laser light incident on its light-receiving surface. Optical sensor 153c is electrically connected to processor 190 and outputs a signal representing the measured pulse energy to processor 190. Processor 190 controls the voltage applied to electrodes 32a and 32b of amplifier 160 based on this signal.

[0073] An emission window 173 is provided on the side of the detector 153 opposite to the output coupling mirror 370 relative to the beam splitter 153b. The emission window 173 is provided on the wall of the housing 110. Light transmitted through the beam splitter 153b is emitted from the emission window 173 to the exposure device 200 outside the housing 110. This laser is, for example, a pulsed laser having a central wavelength of 193.4 nm.

[0074] The display unit 180 is a monitor that displays the control state of the processor 190 based on a signal from the processor 190. The display unit 180 may be disposed outside the housing 110.

[0075] The processor 190 of the present disclosure is a processing device having the same structure as the processor 105. The processor 190 is specially configured or programmed to execute various processes included in the present disclosure.

[0076] 2.2 Action

[0077] Next, the operation of the pulse laser device 120 will be described.

[0078] When the pulse laser device 120 emits laser light, the processor 190 receives a signal indicating target energy Et and a light emission trigger signal from an exposure processor (not shown) of the exposure device 200, for example, via the processor 105. Target energy Et is the target value of the laser energy used in the exposure process. The processor 190 sets a predetermined charging voltage to the charger 41 of the amplifier 160 so that the energy E reaches the target energy Et, and, in synchronization with the light emission trigger signal, turns on the switch of the pulse power module 43 of the laser oscillator 130. The pulse power module 43 then generates a pulsed high voltage based on the electrical energy stored in the charger 41, applying the high voltage between the electrodes 32a and 32b of the laser oscillator 130. The application of the high voltage induces a discharge between the electrodes 32a and 32b, causing the laser medium contained in the laser gas between the electrodes 32a and 32b to enter an excited state. When the laser medium returns to its ground state, light is emitted. The emitted light resonates between the grating 63 and the output coupling mirror 70 of the laser oscillator 130. Each time it passes through the discharge space within the housing 30, it is amplified, causing laser oscillation. The laser light contains a predetermined linear polarization. When passing through windows 31a and 31b, linear polarization with a polarization direction different from the predetermined linear polarization is reduced from the laser light. A portion of the laser light passes through the output coupling mirror 70, is reflected by high-reflection mirrors 141b and 141c, and propagates within the amplifier 160. Within the amplifier 160, the laser light passes through the rear mirror 371 and windows 31a and 31b, continuing to propagate within the housing 30 of the amplifier 160.

[0079] The processor 190 turns on the switch of the pulse power module 43 of the amplifier 160 so that a discharge occurs when the laser light from the laser oscillator 130 propagates into the discharge space within the housing 30 of the amplifier 160. Specifically, the processor 190 controls the pulse power module 43 so that a high voltage is applied to the electrodes 32a and 32b of the amplifier 160 after a predetermined delay time has elapsed from the timing at which the switch of the pulse power module 43 is turned on.

[0080] Thus, the laser light incident on the amplifier 160 is amplified in the amplifier 160. In addition, the laser light propagating into the internal space of the shell 30 propagates to the output coupling mirror 370 via the window 31a as described above, and is reflected by the output coupling mirror 370. The laser light reflected by the output coupling mirror 370 propagates into the internal space of the shell 30 via the window 31a and is emitted from the window 31b. The light emitted from the window 31b is reflected by the rear mirror 371 and propagates into the internal space of the shell 30 via the window 31b. In this way, the laser light of the specified wavelength travels back and forth between the rear mirror 371 and the output coupling mirror 370. The laser light contains specified linear polarization light, and when passing through the windows 31a and 31b, the linear polarization light having a polarization direction different from the polarization direction of the specified linear polarization light is reduced from the laser light. In addition, the laser light is amplified each time it passes through the discharge space inside the shell 30.

[0081] A portion of the laser light from the cavity device CH2 of the amplifier 160 passes through the output coupling mirror 370 and propagates toward the beam splitter 153 b .

[0082] A portion of the amplified laser light that has propagated to the beam splitter 153 b passes through the beam splitter 153 b and the emission window 173 and propagates to the exposure device 200 , while the other portion is reflected by the beam splitter 153 b and propagates to the optical sensor 153 c .

[0083] Optical sensor 153c measures the energy E of the received amplified laser light. Optical sensor 153c outputs a signal representing the measured energy E to processor 190. Processor 190 performs feedback control on the charging voltage of charger 41 to ensure that the difference ΔE between the energy E and the target energy Et falls within an acceptable range. Laser light with a difference ΔE within the acceptable range passes through beam splitter 153b and emission window 173 and is emitted.

[0084] return Figure 2 , the operation of the laser system 100 of the comparative example will be further described. Figure 4 This is a timing diagram showing the relationship between the emission timing of the first pulsed laser L1 by the first pulsed laser device 120a and the emission timing of the second pulsed laser L2 by the second pulsed laser device 120b in this example. The horizontal axis represents time, and the vertical axis represents the intensity of the pulsed laser light. This applies similarly to the other timing diagrams described below.

[0085] As described above, the first and second pulsed laser devices 120a and 120b emit first and second pulsed lasers L1 and L2 at predetermined intervals, with the first and second pulsed lasers L1 and L2 being offset from each other by half the predetermined interval. If the predetermined interval for each of the first and second pulsed lasers L1 and L2 is T, the phases are offset from each other by half a interval, T / 2. The processor 105 controls the first and second pulsed laser devices 120a and 120b to alternately emit the first and second pulsed lasers L1 and L2 as described above.

[0086] The first pulsed laser L1 emitted from the first pulsed laser device 120a is reflected by the reflective mirror 170a and enters the beam combiner 150. Furthermore, the second pulsed laser L2 emitted from the second pulsed laser device 120b is reflected by the reflective mirror 170b and enters the beam combiner 150. The beam combiner 150 emits the first pulsed laser L1 and the second pulsed laser L2 along the same optical path.

[0087] Figure 5 is the pulse coupled light L emitted from the beam combiner 150 12 The first pulse laser L1 emitted from the first pulse laser device 120a and the second pulse laser L2 emitted from the second pulse laser device 120b are alternately emitted from the beam combiner 150. That is, a train of pulse lasers with a period of T / 2, namely, pulse coupled light L, is emitted from the beam combiner 150. 12 .

[0088] In this way, the pulse coupled light L is emitted from the laser system 100 at a repetition frequency twice that of a single pulse laser device. 12 .

[0089] 2.3 Topics

[0090] As the throughput of the exposure device 200 increases, the demand for higher output of the laser system 100 as the light source increases. However, in the case where the beam combiner 150 is a spatial beam coupling method, there is a possibility that the size of the coupled beam or the beam divergence will become larger. Without changing the design of the exposure device, if the beam size or the beam divergence becomes larger, it may occur that a part of the beam cannot be used. Therefore, in order not to change the design of the exposure device, there is a need to suppress the size of the beam size or the beam divergence. In addition, even in the case of redesigning the exposure device, in order to suppress the size of the exposure device and thus make the design and manufacture of the exposure device easier, there is also a need to suppress the size of the beam size or the beam divergence.

[0091] Furthermore, when the beam combiner 150 is of a polarization beam coupling type, two different polarized lights are provided to the exposure device, which may be inappropriate for exposure.

[0092] In the following embodiments, a laser system is exemplified in which a plurality of pulse laser beams emitted from a plurality of pulse laser devices can be used as laser beams suitable for exposure.

[0093] 3. Description of the Laser System of Embodiment 1

[0094] The laser system 100 according to Embodiment 1 will be described. Components identical to those described above are denoted by the same reference numerals, and redundant descriptions will be omitted unless otherwise specified.

[0095] 3.1 Structure

[0096] Figure 6 Schematic diagram showing a schematic configuration example of the laser system 100 according to the first embodiment. Figure 6 As shown, the laser system 100 of this embodiment differs primarily from the laser system 100 of the comparative example in that it includes a first polygonal mirror 360 that reflects the first pulsed laser light L1 and the second pulsed laser light L2, and a processor 350 that controls the emission timing of the first pulsed laser light L1, the emission timing of the second pulsed laser light L2, and the rotation angle of the first polygonal mirror 360 so as to reflect the first pulsed laser light L1 and the second pulsed laser light L2 in the same first direction. As in the comparative example, the first and second pulsed laser devices 120a and 120b emit first and second pulsed laser light L1 and L2 at the same frequency.

[0097] In addition, the first pulse laser device 120 a and the second pulse laser device 120 b may be configured by the laser oscillator 130 as a master oscillator and the amplifier 160 as a power oscillator as in the comparative example, or may be configured by only the laser oscillator 130 without the amplifier 160 .

[0098] The laser system 100 of this embodiment includes a processor 350 in place of the processor 105. The processor 350 is a processing device similar to the processor 105. The processor 350 is specially configured or programmed to execute the various processes included in this embodiment. Furthermore, the processor 350 is electrically connected to the processors 190 included in the first and second pulsed laser devices 120a and 120b and the exposure processor (not shown) of the exposure device 200, and various signals are transmitted and received between the processors.

[0099] The first polygonal mirror 360 includes N mirrors with a fixed angle between adjacent mirrors. N is a natural number greater than or equal to 3. In addition, in this embodiment, an example in which N is 4 is shown. The first polygonal mirror 360 is connected to a drive unit (not shown) and rotates at a substantially constant speed with the central axis C as the rotation axis. When the repetition frequency of the first pulsed laser L1 emitted from the first pulsed laser device 120a and the second pulsed laser L2 emitted from the second pulsed laser device 120b is X [Hz], the number of revolutions per unit time of the first polygonal mirror 360 is preferably X / N [rps]. In this embodiment, since N = 4, the number of revolutions per unit time of the first polygonal mirror 360 is X / 4 [rps]. However, the number of revolutions per unit time of the first polygonal mirror 360 including N mirrors is not limited to X / N [rps], and can be, for example, 2X / N [rps]. The drive unit of the first polygonal mirror 360 is electrically connected to the processor 350, and the rotation speed of the first polygonal mirror 360 is controlled by the processor 350.

[0100] It is preferable that the incident angle θ of the first pulse laser L1 incident on the first polygon mirror 360 from the first pulse laser device 120a and the incident angle θ of the second pulse laser L2 incident on the first polygon mirror 360 from the second pulse laser device 120b are equal to are the same angles. When the first polygon mirror 360 includes N reflecting mirrors, the incident angle is preferably 360 / 4N[°]. In this embodiment, since N=4, the incident angle is

[0101] Each reflector of the first polygonal mirror 360 is formed, for example, of a multilayer film. In this case, the film of each reflector is formed so as to reflect the first and second pulsed laser beams L1 and L2 from the first and second pulsed laser devices 120a and 120b at a high reflectivity when incident at a predetermined angle of incidence. Therefore, in this example, the reflectivity of each reflector is preferably highest at an angle of incidence of 22.5°.

[0102] The first pulsed laser light L1 and the second pulsed laser light L2 reflected by the first polygon mirror 360 propagate in the same first direction. Moreover, at least a portion of the optical paths of the first pulsed laser light L1 and the second pulsed laser light L2 reflected by the first polygon mirror 360 overlap. Therefore, the pulse coupled light L1 emitted from the first polygon mirror 360 12 .

[0103] The laser system 100 of this embodiment further includes beam steering devices 310a and 310b, which are disposed in the optical paths of the first and second pulsed laser beams L1 and L2 emitted from the first and second pulsed laser beams 120a and 120b and incident on the first polygonal mirror 360, and adjust the optical paths of the first and second pulsed laser beams L1 and L2. Specifically, the beam steering devices 310a and 310b are disposed upstream of the first polygonal mirror 360.

[0104] The beam steering devices 310 a and 310 b have the same structure as each other, and therefore the beam steering devices 310 a and 310 b will be referred to as the beam steering device 310 in the following description. Figure 7 This is a schematic diagram showing an example of the general configuration of the beam steering device 310. The beam steering device 310 includes mirrors 420a and 420b and actuators 410a and 410b that respectively change the orientation of the mirrors 420a and 420b. The actuators 410a and 410b are electrically connected to the processor 350, which controls at least one of their position and angle to adjust the optical paths of the first and second pulsed laser beams L1 and L2 emitted from the beam steering device 310.

[0105] Furthermore, the beam steering device 310 may be disposed between one of the first pulsed laser device 120a and the second pulsed laser device 120b and the first polygonal mirror 360, rather than being disposed in the optical path of the other. Furthermore, if the first and second pulsed laser beams L1 and L2 are emitted from the first and second pulsed laser devices 120a and 120b in appropriate directions, the laser system 100 may not include the beam steering device 310.

[0106] In this embodiment, the laser system 100 includes a mirror 331 that reflects the second pulsed laser light L2 . The second pulsed laser light L2 emitted from the second pulsed laser device 120 b and passing through the beam steering device 310 b is reflected by the mirror 331 and enters the first polygon mirror 360 .

[0107] Furthermore, the laser system 100 of this embodiment includes a beam measuring device 320 that measures at least one of the beam positions and orientations (directions) of the first and second pulsed laser beams L1 and L2 reflected by the first polygon mirror 360 .

[0108] Figure 8 Schematic diagram showing a schematic configuration example of the beam measuring device 320. The beam measuring device 320 includes a beam splitter 430 and a light sensor 440. The beam splitter 430 splits the pulse coupled light L 12Part of the beam is reflected toward optical sensor 440, while another part is transmitted. Optical sensor 440 is electrically connected to processor 350. Optical sensor 440 includes a light-receiving surface for receiving light, measures at least one of the beam position and orientation on the light-receiving surface, and transmits the measurement results to processor 350. Beam measurement device 320 is preferably also capable of measuring pulse energy, power, wavelength, spectrum, and the like.

[0109] The processor 350 controls the beam steering devices 310a and 310b based on the measurement results of the beam measuring device 320 so that the optical path of the first pulsed laser light L1 reflected by the first polygon mirror 360 and the optical path of the second pulsed laser light L2 reflected by the first polygon mirror 360 are close to each other. In addition, the processor 350 controls the first pulsed laser device 120a, the second pulsed laser device 120b, the beam steering devices 310a and 310b, and the first polygon mirror 360 based on the measurement results of the beam measuring device 320 to adjust the pulsed coupled light L 12 intensity and optical path to achieve the optimal beam power for exposure device 200.

[0110] In addition, the beam measuring device 320 may be provided outside the laser system 100. In addition, the laser system 100 may not include the beam measuring device 320.

[0111] In addition, in this embodiment, the laser system 100 includes a reflected pulse coupled light L 12 The pulse coupled light L emitted from the first polygon mirror 360 12 The light is reflected by the mirror 332 and enters the beam measuring device 320 .

[0112] In this embodiment, the pulse coupled light L 12 A pulse stretcher 325 is provided on the propagation optical path. The pulse stretcher 325 temporally stretches the pulse widths of the first pulse laser L1 and the second pulse laser L2. That is, the pulse stretcher 325 is provided downstream of the first polygon mirror 360. The pulse stretcher 325 includes, for example, a beam splitter, which is arranged between the pulse coupled light L1 and the second pulse laser L2. 12 On the optical path, the pulse coupled light L 12 and a plurality of reflectors, which branch the pulse coupled light L 12 Multiple reflections make it relative to the pulse coupling light L passing through the beam splitter 12 Delay. The delayed pulse coupling light L 12 The pulse coupled light L that passes through the beam splitter is returned to 12 The light path is the same as the light path.

[0113] The pulse stretcher 325 can be located upstream of the first polygonal mirror 360, but is preferably located downstream of the first polygonal mirror 360. When located upstream of the first polygonal mirror 360, the first and second pulsed laser beams L1 and L2, whose pulse widths have been temporally expanded, are reflected by the rotating first polygonal mirror 360, making it easier for the optical paths of the reflected first and second pulsed laser beams L1 and L2 to shift. In contrast, when the pulse stretcher 325 is located downstream of the first polygonal mirror 360, the first and second pulsed laser beams L1 and L2 are reflected by the first polygonal mirror 360 before their pulse widths have been temporally expanded, making it easier for the first and second pulsed laser beams L1 and L2 to be reflected in the same direction. Alternatively, the pulse stretcher 325 may be omitted.

[0114] In this embodiment, if Figure 6 As shown, the emission direction of the first pulse laser L1 emitted from the first pulse laser device 120a and the emission direction of the second pulse laser L2 emitted from the second pulse laser device 120b are the same as the pulse coupled light L composed of the first and second pulse lasers L1 and L2 emitted from the laser system 100. 12 By emitting the first pulse laser L1 and the second pulse laser L2 in this way, the number of mirrors and the like that reflect the first pulse laser L1 and the second pulse laser L2 can be reduced, the layout can be made more efficient, and the size of the laser system 100 can be reduced. However, the emission direction of the first pulse laser L1 emitted from the first pulse laser device 120a and the emission direction of the second pulse laser L2 emitted from the second pulse laser device 120b may not be the same as the emission direction of the pulse coupled light L1 emitted from the laser system 100. 12 The direction opposite to the direction of emission.

[0115] 3.2 Action

[0116] The processor 350 causes the first and second pulse laser devices 120a and 120b to emit the first and second pulse lasers L1 and L2 in the same manner as in the comparative example. Figure 4 As shown, the first and second pulsed lasers L1 and L2 are emitted with an offset of one-half of a predetermined period T. The first and second pulsed lasers L1 and L2 emitted from the first and second pulsed laser devices 120a and 120b have their optical paths adjusted by beam steering devices 310a and 310b, are incident on the first polygonal mirror 360, and are reflected by the reflecting surface of the first polygonal mirror 360.

[0117] Here, it is assumed that the angle formed by the first pulsed laser light L1 incident on the first polygonal mirror 360 and the second pulsed laser light L2 incident on the first polygonal mirror 360 is 90°. Figure 6In the figure, the solid line represents the state of the first polygon mirror 360 at the time of the first pulse laser L1 incident, and the dotted line represents the state of the first polygon mirror 360 at the time of the second pulse laser L2 incident. The two states of the first polygon mirror 360 are rotated 45 degrees relative to each other. In this case, when the absolute spatial coordinates of the position where the first pulse laser L1 is incident on the first polygon mirror 360 coincide with the absolute spatial coordinates of the position where the second pulse laser L2 is incident on the first polygon mirror 360, the optical path propagated by the first pulse laser L1 after being reflected by the first polygon mirror 360 and the optical path propagated by the second pulse laser L2 after being reflected by the first polygon mirror 360 become the same optical path. In other words, the optical axes coincide. In addition, even when the first pulse laser L1 and the second pulse laser L2 are reflected by the same reflection surface, the reflection position of the first pulse laser L1 and the reflection position of the second pulse laser L2 on that reflection surface can be different from each other.

[0118] The processor 350 controls the emission timing of the first pulse laser device 120a, the emission timing of the second pulse laser device 120b, and the rotation angle of the first polygon mirror 360 so that the first and second pulse lasers L1 and L2 reflected by the first polygon mirror 360 are reflected in the same first direction. Figure 6 As shown, each pulse laser becomes pulse coupled light L 12 , propagating along the same optical path. Furthermore, as long as the optical paths of the first and second pulsed laser beams L1 and L2 are oriented in the same first direction and at least partially overlap, their optical axes do not need to be completely aligned. However, it is preferred that the optical axis of the first pulsed laser beam L1 and the optical axis of the second pulsed laser beam L2, after reflection by the first polygonal mirror 360, be aligned. Furthermore, the alignment of the first direction can be within a range of 0.1°.

[0119] In this embodiment, the first polygon mirror 360 reflects the first and second pulsed lasers L1 and L2 in a first direction between the incident first and second pulsed lasers L1 and L2. The first and second pulsed lasers L1 and L2 reflected by the first polygon mirror 360 are pulse coupled light L 12 The light propagates between the optical paths of the first and second pulsed laser beams L1 and L2 incident on the first polygon mirror 360 , and propagates between the first pulsed laser device 120 a and the second pulsed laser device 120 b .

[0120] The pulse coupled light L emitted from the first polygon mirror 360 12 The pulse coupled light L is incident on the beam measuring device 320 via the mirror 332. The processor 350 controls the beam steering device 310 based on the measurement result measured by the beam measuring device 320 so that the pulse coupled light L 12The beam position and direction are within a specified range. Specifically, processor 350 controls beam steering device 310 based on the measurement results of beam measuring instrument 320 to ensure that the optical paths of first pulsed laser light L1 and second pulsed laser light L2, after being reflected by first polygon mirror 360, are close to each other. Beam measuring instrument 320 can also measure the pulse energy, power, wavelength, and spectrum of each pulsed light.

[0121] The pulse coupled light L that has passed through the beam measuring device 320 12 The light enters the pulse stretcher 325 , has its pulse width extended in time, and is emitted from the pulse stretcher 325 .

[0122] In this way, the laser system 100 emits pulse coupled light L having a repetition frequency twice that of the first and second pulse laser beams L1 and L2. 12 .

[0123] 3.3 Function and effect

[0124] The laser system 100 includes: a first pulse laser device 120a, which emits a first pulse laser L1 with a specified period T; a second pulse laser device 120b, which emits a second pulse laser L2 with a specified period T; a first polygonal mirror 360, which reflects the first pulse laser L1 and the second pulse laser L2; and a processor 350, which controls the first pulse laser device 120a, the second pulse laser device 120b and the first polygonal mirror 360, so that the first pulse laser L1 and the second pulse laser L2 are emitted with a gap of half the specified period T, and the optical paths of the first pulse laser L1 and the second pulse laser L2 after being reflected by the first polygonal mirror 360 are directed to the same first direction and at least partially overlap.

[0125] The laser system 100 of this embodiment emits pulse coupled light L at a repetition frequency twice that of a single pulse laser device. 12 In addition, the pulse coupled light L composed of the first and second pulse lasers L1 and L2 can be suppressed. 12 The beam size and beam divergence of the pulse coupled light L 12 The polarization direction is fixed. Therefore, the laser system 100 of this embodiment can emit laser light suitable for exposure. In addition, the first and second pulsed lasers L1 and L2 can be reflected at the same incident angle by the same polygon mirror to form pulse coupled light L 12 , so that the pulse coupled light L 12 The energy and light quality of each pulse laser are close to each other. In addition, pulse coupling light L can be easily performed. 12 Adjust the optical path.

[0126] In addition, the pulse coupled light L 12In the case where the optical path of the laser beam emitted from any pulse laser device 120 is not propagated in the space between the first pulse laser device 120a and the second pulse laser device 120b, the structure of the laser system 100 may become complicated if an optical path tube or the like is used to cover the optical path and make the surrounding of the laser beam into a predetermined atmosphere. However, in this embodiment, the first polygon mirror 360 reflects the first and second pulse laser beams L1 and L2 in the direction between the first and second pulse laser beams L1 and L2 incident on the first polygon mirror 360, and the pulse coupled light L 12 The pulse coupled light L is transmitted between the first pulse laser device 120a and the second pulse laser device 120b. 12 The optical paths of the first and second pulsed laser beams L1 and L2 incident on the first polygon mirror 360 do not intersect, and the structure of the laser system 100 can be simplified.

[0127] 3.4 Variations

[0128] Next, a modification of the first embodiment will be described. Figure 9 1 is a schematic diagram showing a schematic configuration example of a laser system 100 according to this modification. The laser system 100 according to this modification differs from the laser system 100 according to the above embodiment in that the number of reflecting surfaces of the first polygon mirror 360 is different.

[0129] The number N of reflective surfaces of the first polygonal mirror 360 in this variation is 8, which is greater than the number of reflective surfaces of the first polygonal mirror 360 in the aforementioned embodiment. Therefore, the number of revolutions per unit time of the first polygonal mirror 360 in this variation can be reduced compared to the number of revolutions per unit time of the first polygonal mirror 360 in the aforementioned embodiment. For example, in the aforementioned embodiment, since the number N of reflective surfaces is 4, when the repetition frequency of the first and second pulsed laser beams L1 and L2 is X [Hz], the number of revolutions per unit time of the first polygonal mirror 360 is X / 4 [rps]. In contrast, in this variation, the number of revolutions per unit time of the first polygonal mirror 360 can be X / 8 [rps]. This further reduces the number of revolutions per unit time of the first polygonal mirror 360, making it easier to control the laser system 100. Furthermore, the amount of change in the angle of the reflective surface during the period in which a pulse is reflected by the reflective surface can be reduced, thereby suppressing deviations in the optical paths of the first and second pulsed laser beams L1 and L2 reflected by the first polygonal mirror 360.

[0130] Here, it is preferable that the incident angle θ of the first pulse laser L1 incident on the first polygon mirror 360 from the first pulse laser device 120a and the incident angle θ of the second pulse laser L2 incident on the first polygon mirror 360 from the second pulse laser device 120b are equal to are equal to each other. At each incident angle θ, When the first polygon mirror 360 includes N reflecting mirrors, the incident angle is preferably 360 / 4N[°]. In this modification, since N=8, the incident angle is θ=

[0131] In addition, the number N of reflecting mirrors of the first polygon mirror 360 is not limited to 4 or 8, and may be a natural number of 3 or greater.

[0132] 4. Description of the Laser System of Implementation Method 2

[0133] A laser system 100 according to Embodiment 2 will be described. Components identical to those described above are denoted by the same reference numerals, and redundant descriptions will be omitted unless otherwise specified.

[0134] 4.1 Structure

[0135] Figure 10 Schematic diagram showing an example of the general structure of the laser system 100 of the second embodiment. The laser system 100 of this embodiment differs from the first embodiment mainly in that the first embodiment includes two first and second pulse laser devices 120a and 120b, and a first polygon mirror 360 generates pulse coupled light L 12 In contrast, this embodiment comprises first to fourth pulse laser devices 120a to 120d, which generate third pulse coupled light L by three polygon mirrors, namely, a first polygon mirror 360a, a second polygon mirror 360b and a third polygon mirror 360c. 1-4 In addition, to avoid complicating the diagram, Figure 10 In the figures and subsequent figures, the electrical wiring of the processor 350 is omitted.

[0136] The first polygon mirror 360a has the same structure as the first polygon mirror 360 in the first embodiment. As in the first embodiment, it reflects the first pulse laser L1 and the second pulse laser L2 toward the first direction to generate the pulse coupled light L1 described in the first embodiment. 12 The same first pulse coupling light L 12 .

[0137] The third and fourth pulsed laser devices 120c and 120d have the same structure as the first and second pulsed laser devices 120a and 120b, and emit third and fourth pulsed lasers L3 and L4 at a predetermined period T. The third and fourth pulsed lasers L3 and L4 emitted from the third and fourth pulsed laser devices 120c and 120d are incident on the second polygonal mirror 360b. In this embodiment, the laser system 100 includes a mirror 333 for reflecting the fourth pulsed laser L4. The fourth pulsed laser L4 emitted from the fourth pulsed laser device 120d is reflected by the mirror 333 and is incident on the second polygonal mirror 360b.

[0138] In addition, a beam steering device for adjusting the optical path can also be provided in the optical path from the first and second pulse laser devices 120a, 120b to at least one side of the first polygonal mirror 360a, and in the optical path from the third and fourth pulse laser devices 120c, 120d to at least one side of the second polygonal mirror 360b, in the same manner as in embodiment 1.

[0139] The second polygon mirror 360b has the same structure as the first polygon mirror 360a, and reflects the third pulse laser L3 and the fourth pulse laser L4 toward the second direction to generate the second pulse coupled light L 34 .

[0140] The first pulse coupled light L emitted from the first polygon mirror 360a 12 and the second pulse coupled light L emitted from the second polygon mirror 360b 34 In this embodiment, the first pulse coupled light L 12 The light is reflected by the mirror 332 and enters the third polygon mirror 360c. In addition, in this embodiment, the laser system 100 includes a light source that reflects the second pulse coupled light L 34 The second pulse coupled light L emitted from the second polygon mirror 360b 34 The light is reflected by the mirrors 334 and 335 and enters the third polygon mirror 360 c .

[0141] The third polygon mirror 360c has the same structure as the first polygon mirror 360a, and transmits the first pulse coupled light L 12 and the second pulse coupling light L 34 The light is reflected in the third direction to generate the third pulse coupled light L 1-4 In this embodiment, the laser system 100 includes a device for reflecting the third pulse coupled light L 1-4 The third pulse coupled light L emitted from the third polygon mirror 360c 1-4 The light is reflected by the mirror 336 and emitted from the laser system 100. 1-4 A beam measuring device 320 and a pulse stretcher 325 are provided on the optical path in the same manner as in the first embodiment.

[0142] The processor 350 of this embodiment controls the first pulse laser device 120a, the second pulse laser device 120b, the third pulse laser device 120c, the fourth pulse laser device 120d, the first polygon mirror 360a, the second polygon mirror 360b, and the third polygon mirror 360c as described below.

[0143] 4.2 Action

[0144] In this embodiment, the first polygon mirror 360a reflects the first and second pulsed lasers L1 and L2 in a first direction between the incident first and second pulsed lasers L1 and L2. The first and second pulsed lasers L1 and L2 reflected by the first polygon mirror 360a are pulse coupled light L 12 The light propagates between the optical paths of the first and second pulsed laser beams L1 and L2 incident on the first polygon mirror 360a, and propagates between the first pulsed laser device 120a and the second pulsed laser device 120b. In addition, the second polygon mirror 360b reflects the third and fourth pulsed laser beams L3 and L4 in a second direction between the incident third and fourth pulsed laser beams L3 and L4. The third and fourth pulsed laser beams L3 and L4 reflected by the second polygon mirror 360b are the pulse coupled light L 34 The light propagates between the optical paths of the third and fourth pulsed lasers L3 and L4 incident on the second polygon mirror 360b, and propagates between the third pulsed laser device 120c and the fourth pulsed laser device 120d. By setting it as such, the number of mirrors can be reduced, the layout can be made more efficient, and the laser system 100 can be reduced in size.

[0145] Figure 11 1 and 2 are timing charts showing the relationship between the emission timings of the first to fourth pulsed laser beams L1 to L4. The emission timings of the first and second pulsed laser beams L1 and L2 emitted by the first and second pulsed laser devices 120a and 120b are the same as those in the first embodiment.

[0146] The emission timings of the third and fourth pulsed lasers L3 and L4 emitted by the third and fourth pulsed laser devices 120c and 120d are offset from the emission timings of the first and second pulsed lasers L1 and L2 by one-quarter of the predetermined period T, i.e., T / 4. In this example, the emission timing of the third pulsed laser L3 is delayed relative to the emission timing of the first pulsed laser L1 by one-quarter of the predetermined period T, and is advanced relative to the emission timing of the second pulsed laser L2 by one-quarter of the predetermined period T. Furthermore, the emission timing of the fourth pulsed laser L4 is advanced relative to the emission timing of the first pulsed laser L1 by one-quarter of the predetermined period T, and is delayed relative to the emission timing of the second pulsed laser L2 by one-quarter of the predetermined period T.

[0147] The first pulse laser light L1 emitted from the first pulse laser device 120a and the second pulse laser light L2 emitted from the second pulse laser device 120b are respectively reflected by the first polygon mirror 360a and are converted into the first pulse coupled light L 12 The processor 350 controls the emission timing of the first pulse laser device 120a and the second pulse laser device 120b and the rotation angle of the first polygon mirror 360a in the same manner as in the first embodiment.

[0148] The third pulse laser light L3 emitted from the third pulse laser device 120c and the fourth pulse laser light L4 emitted from the fourth pulse laser device 120d are respectively reflected by the second polygon mirror 360b and converted into the second pulse coupled light L 34 The processor 350 controls the emission timing of the third pulse laser device 120c, the emission timing of the fourth pulse laser device 120d, and the rotation angle of the second polygonal mirror 360b so that at least a portion of the optical path of the third pulse laser L3 reflected by the second polygonal mirror 360b overlaps with at least a portion of the optical path of the fourth pulse laser L4 reflected by the second polygonal mirror 360b, and reflects the third pulse laser L3 and the fourth pulse laser L4 in the same second direction.

[0149] Figure 12 is the first pulse coupled light L 12 Coupled with the second pulse light L 34 The first pulse coupled light L having a period of T / 2 is emitted from the first polygon mirror 360a. 12 The second pulse coupled light L with a period of T / 2 is emitted from the second polygon mirror 360b. 34 As described above, the emission timing of the third and fourth pulse lasers L3 and L4 is shifted from the emission timing of the first and second pulse lasers L1 and L2 by one quarter of the predetermined period T, so the first pulse coupled light L 12 The emission timing of the second pulse coupling light L 34 The emission timing is shifted by one quarter of the prescribed period T. The number of rotations per unit time of the third polygon mirror 360c is twice that of the first polygon mirror 360a and the second polygon mirror 360b. Alternatively, as in the modified example of the first embodiment, the third polygon mirror 360c may have twice as many reflecting surfaces as the first polygon mirror 360a and the second polygon mirror 360b, and the number of rotations per unit time of the third polygon mirror 360c is the same as that of the first polygon mirror 360a and the second polygon mirror 360b.

[0150] The first and second pulse coupled light beams L emitted from the first and second polygon mirrors 360a and 360b 12 、L 34 The light is reflected by the third polygon mirror 360c and becomes the third pulse coupled light L 1-4 Shoot out.

[0151] Figure 13 is the third pulse coupled light L 1-4 As described above, the emission timings of the first to fourth pulse lasers L1 to L4 are shifted by 1 / 4 of the prescribed period T. Therefore, the third pulse coupled light L 1-4The period is 1 / 4 of the predetermined period T. Thus, the third pulse coupled light L having a period of T / 4 is emitted from the third polygon mirror 360c. 1-4 .

[0152] Therefore, the processor 350 of this embodiment controls the first to fourth pulse laser devices 120a to 120d and the first to third polygonal mirrors 360a to 360c so that the optical paths of the first to fourth pulse lasers L1 to L4 reflected by the third polygonal mirror 360c are directed in the same third direction and at least partially overlap.

[0153] In addition, the third pulse coupling light L 1-4 A beam measuring device 320 and a pulse stretcher 325 are provided on the optical path in the same manner as in the first embodiment.

[0154] 4.3 Function and effect

[0155] According to the laser system 100 of this embodiment, it is possible to emit pulse laser light toward the exposure device 200 at a repetition frequency four times higher than that of one pulse laser device 120 .

[0156] 4.4 Variations

[0157] Figure 14 Schematic diagram showing a schematic configuration example of a laser system 100 in a modified example of Embodiment 2. In the description of this modified example, identical components to the aforementioned laser system 100 are denoted by the same reference numerals, and duplicate descriptions are omitted unless otherwise specified. The laser system 100 in this modified example differs from the laser system 100 in Embodiment 2 primarily in that the first polygon mirror 360a also serves as the second polygon mirror 360b.

[0158] The first polygon mirror 360a has the same structure as the first polygon mirror 360 in the first embodiment. As in the first embodiment, it reflects the first pulse laser L1 and the second pulse laser L2 toward the first direction to generate the pulse coupled light L1 described in the first embodiment. 12 The same first pulse coupling light L 12 In this modification, the laser system 100 includes mirrors 337 and 338 for reflecting the first pulsed laser light L1 . The first pulsed laser light L1 emitted from the first pulsed laser device 120 a is reflected by the mirrors 337 and 338 and enters the first polygon mirror 360 a .

[0159] Furthermore, the first polygon mirror 360a reflects the third pulse laser light L3 and the fourth pulse laser light L4 toward the second direction, thereby generating the second pulse coupled light L described in the second embodiment. 34 The same second pulse coupling light L 34 .

[0160] The third polygon mirror 360c has the same structure as the first polygon mirror 360a in the first embodiment, and is the same as the second embodiment. 12 and the second pulse coupling light L 34 The light is reflected in the third direction to generate the third pulse coupled light L described in the second embodiment. 1-4 The same third pulse coupling light L 1-4 The number of rotations per unit time of the third polygon mirror 360c is twice that of the first polygon mirror 360a.

[0161] A beam steering device for adjusting the optical path can also be provided in the same manner as in embodiment 1 on the optical path from the first and second pulse laser devices 120a, 120b to at least one side of the first polygonal mirror 360a, and on the optical path from the third and fourth pulse laser devices 120c, 120d to at least one side of the first polygonal mirror 360a.

[0162] Next, the operation of the modified example will be described.

[0163] The emission timing of the first to fourth pulse laser beams L1 to L4 is the same as that of the above-mentioned embodiment 2. In addition, the first pulse coupled light L emitted by the first polygon mirror 360a is 12 Coupled with the second pulse light L 34 The relationship of the injection timing is also the same as that in the above-mentioned embodiment 2.

[0164] The first pulsed laser light L1 emitted from the first pulsed laser device 120a is reflected by mirrors 337 and 338 and enters the first polygonal mirror 360a. At this time, the first and second pulsed laser lights L1 and L2 enter the same first reflection surface. However, the rotation angle of the first polygonal mirror 360a when the first pulsed laser light L1 enters differs from the rotation angle of the first polygonal mirror 360a when the second pulsed laser light L2 enters.

[0165] The third and fourth pulsed laser beams L3 and L4 emitted from the third and fourth pulsed laser devices 120c and 120d are incident on the first polygonal mirror 360a. At this time, the reflection surface onto which the third and fourth pulsed laser beams L3 and L4 are incident is the same second reflection surface. Here, the second reflection surface is different from the first reflection surface. The rotation angle of the first polygonal mirror 360a when the third pulsed laser beam L3 is incident is different from the rotation angle of the first polygonal mirror 360a when the fourth pulsed laser beam L4 is incident.

[0166] The first polygon mirror 360a reflects the first pulse laser L1 and the second pulse laser L2 toward the first direction to generate the first pulse coupled light L 12 .

[0167] In addition, the first polygon mirror 360a reflects the third pulse laser L3 and the fourth pulse laser L4 toward the second direction to generate the second pulse coupled light L 34 .

[0168] The third polygon mirror 360c couples the first pulsed light L 12 and the second pulse coupling light L 34 The light is reflected in the third direction to generate the third pulse coupled light L 1-4 .

[0169] The processor 350 of this variation controls the first to fourth pulsed laser devices 120a to 120d and the first and third polygonal mirrors 360a and 360c so that the optical paths of the first to fourth pulsed lasers L1 to L4 reflected by the third polygonal mirror 360c face the same third direction and at least partially overlap.

[0170] In addition, the third pulse coupling light L 1-4 A beam measuring device 320 and a pulse stretcher 325 are provided on the optical path in the same manner as in the second embodiment.

[0171] According to the configuration of this modification, one polygon mirror can be omitted compared to the configuration of the second embodiment, and thus the configuration of the device can be simplified.

[0172] The above description is not limiting but merely illustrative. Therefore, it is obvious to those skilled in the art that the embodiments of the present disclosure can be changed without departing from the claims. In addition, it is obvious to those skilled in the art that the embodiments of the present disclosure are used in combination. Unless otherwise expressly stated, the terms used in this specification and the 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 "not excluding the presence of constituent elements other than the constituent elements described". In addition, the modifier "1" should be interpreted as "at least 1" or "1 or more". In addition, the term "at least one of A, B and C" should be interpreted as "A", "B", "C", "A+B", "A+C", "B+C" or "A+B+C", and should also be interpreted as a combination of parts other than "A", "B" and "C".

Claims

1. A laser system comprising: a first pulse laser device that emits a first pulse laser at a predetermined period; a second pulse laser device that emits a second pulse laser at the predetermined period; a first polygonal mirror that reflects the first pulsed laser light and the second pulsed laser light; and A processor controls the first pulse laser device, the second pulse laser device, and the first polygonal mirror so that the first pulse laser and the second pulse laser are emitted with a shift of half the prescribed period, and the optical paths of the first pulse laser and the second pulse laser after being reflected by the first polygonal mirror are directed in a first direction and at least partially overlap.

2. The laser system according to claim 1, wherein: The first polygonal mirror comprises N reflecting mirrors whose angles formed by adjacent reflecting mirrors are fixed. When a frequency that is the reciprocal of the predetermined period is X [Hz], the number of rotations of the first polygon mirror per unit time is X / N [rps].

3. The laser system according to claim 2, wherein: An incident angle of the first pulsed laser on the reflecting mirror of the first polygonal mirror and an incident angle of the second pulsed laser on the reflecting mirror of the first polygonal mirror are 360 / 4N[°].

4. The laser system according to claim 2, wherein: The N is 4 or more and 8 or less.

5. The laser system according to claim 1, wherein: The laser system further includes a beam steering device that adjusts at least one of the optical paths of the first pulsed laser light and the second pulsed laser light incident on the first polygon mirror.

6. The laser system according to claim 5, wherein: The laser system further includes a beam measuring device that measures at least one of the beam positions and directions of the first pulse laser light and the second pulse laser light reflected by the first polygon mirror.

7. The laser system according to claim 6, wherein: The processor controls the beam steering device based on the measurement result of the beam measuring instrument so that the optical paths of the first pulse laser and the second pulse laser reflected by the first polygon mirror approach each other.

8. The laser system of claim 1, wherein: The first pulse laser light and the second pulse laser light reflected by the first polygon mirror propagate between an optical path of the first pulse laser light incident on the first polygon mirror and an optical path of the second pulse laser light incident on the first polygon mirror.

9. The laser system of claim 1 , wherein: The first pulse laser and the second pulse laser reflected by the first polygon mirror propagate between the first pulse laser device and the second pulse laser device.

10. The laser system of claim 1, wherein: The emission direction of the first pulse laser light emitted from the first pulse laser device and the emission direction of the second pulse laser light emitted from the second pulse laser device are opposite to the emission direction of the pulse laser light emitted from the laser system.

11. The laser system of claim 1 , wherein: The laser system further includes a pulse stretcher that stretches the pulse widths of the first pulse laser light and the second pulse laser light reflected by the first polygonal mirror.

12. The laser system of claim 1, wherein: The laser system also has: a third pulse laser device that emits a third pulse laser at the predetermined period; a fourth pulse laser device for emitting a fourth pulse laser at the predetermined period; a second polygonal mirror reflecting the third pulse laser and the fourth pulse laser; as well as a third polygonal mirror that reflects the first pulsed laser light and the second pulsed laser light reflected by the first polygonal mirror and the third pulsed laser light and the fourth pulsed laser light reflected by the second polygonal mirror; The processor controls the first pulse laser device, the second pulse laser device, the third pulse laser device, the fourth pulse laser device, the first polygonal mirror, the second polygonal mirror and the third polygonal mirror so that the third pulse laser and the fourth pulse laser are offset by half of the prescribed period and are emitted offset by a quarter of the prescribed period from the first pulse laser and the second pulse laser, so that the optical paths of the third pulse laser and the fourth pulse laser after being reflected by the second polygonal mirror are directed in the second direction and at least partially overlap, and the optical paths of the first pulse laser, the second pulse laser, the third pulse laser and the fourth pulse laser after being reflected by the third polygonal mirror are directed in the third direction and at least partially overlap.

13. The laser system of claim 12, wherein: The first polygonal mirror also serves as the second polygonal mirror.

14. A method for manufacturing an electronic device, comprising the following steps: outputting the first pulse laser and the second pulse laser generated by the laser system to the exposure device; and exposing the first pulse laser and the second pulse laser on a photosensitive substrate in the exposure device to manufacture an electronic device, The laser system comprises: a first pulse laser device that emits the first pulse laser at a predetermined period; a second pulse laser device that emits the second pulse laser at the predetermined period; a first polygonal mirror reflecting the first pulsed laser and the second pulsed laser; as well as A processor controls the first pulse laser device, the second pulse laser device, and the first polygonal mirror so that the first pulse laser and the second pulse laser are emitted with a shift of half the prescribed period, and the optical paths of the first pulse laser and the second pulse laser after being reflected by the first polygonal mirror are directed in a first direction and at least partially overlap.

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