Laser device and method for manufacturing electronic device

Abstract

A laser device is provided with: an oscillator that emits pulsed seed light; a first amplifier that amplifies the seed light and emits first amplified light; a first pulse expander that expands the pulse width of the first amplified light; a beam splitter that splits the first amplified light having the expanded pulse width into a first split light and a second split light having a smaller energy than the first split light; a second amplifier that amplifies a portion of the second divided light and emits a second amplified light; a second pulse expander that expands the pulse width of the second amplified light; and a beam combiner that emits coupled light in which the first split light and the second amplified light having the expanded pulse width are coupled.

Description

Technical Field

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

[0002] In recent years, in semiconductor exposure apparatuses, as semiconductor integrated circuits have been miniaturized and highly integrated, there has been a demand for higher resolution. Therefore, efforts have been made to shorten the wavelength of light emitted from an exposure light source. For example, as a gas laser device for exposure, a KrF excimer laser device that emits laser light with an output wavelength of about 248 nm and an ArF excimer laser device that emits laser light with an output wavelength of about 193 nm are used.

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

[0004] Prior Art Documents

[0005] Patent Documents

[0006] [Patent Document 1] U.S. Patent Application Publication No. 2008 / 144671 Summary of the Invention

[0007] A laser device according to one aspect of the present disclosure includes: an oscillator that emits pulsed seed light; a first amplifier that amplifies the seed light and emits first amplified light; a first pulse expander that expands the pulse width of the first amplified light; a beam splitter that splits the first amplified light with the expanded pulse width into first split light and second split light having an energy smaller than that of the first split light; a second amplifier that amplifies a part of the second split light and emits second amplified light; a second pulse expander that expands the pulse width of the second amplified light; and a combiner that emits combined light obtained by coupling the first split light and the second amplified light with the expanded pulse width.

[0008] A method for manufacturing an electronic device according to one aspect of the present disclosure includes the following steps: generating laser light by a laser device; outputting the laser light to an exposure device; and exposing the laser light on a photosensitive substrate in the exposure device in order to manufacture the electronic device. The laser device includes: an oscillator that emits pulsed seed light; a first amplifier that amplifies the seed light and emits first amplified light; a first pulse stretcher that expands the pulse width of the first amplified light; a beam splitter that splits the first amplified light with the expanded pulse width into a first split light and a second split light having an energy smaller than that of the first split light; a second amplifier that amplifies a part of the second split light and emits second amplified light; a second pulse stretcher that expands the pulse width of the second amplified light; and a combiner that emits combined light obtained by coupling the first split light and the second amplified light with the expanded pulse width. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Hereinafter, some embodiments of the present disclosure will be described with reference to the drawings by way of example only.

[0010] Figure 1 Shows the structure of the exposure system in the comparative example.

[0011] Figure 2 Shows the structure of the laser device in the comparative example.

[0012] Figure 3 Schematically shows the structure of the laser device according to the first embodiment.

[0013] Figure 4 Is a timing chart showing the oscillation trigger signals and the pulse time waveforms of the laser light of the respective parts of the laser device according to the first embodiment.

[0014] Figure 5 Schematically shows the structure of the laser device according to the second embodiment.

[0015] Figure 6 Is a timing chart showing the oscillation trigger signals and the pulse time waveforms of the laser light of the respective parts of the laser device according to the second embodiment.

[0016] Figure 7 Is a flowchart of the control of the applied voltage executed by the processor in the first and second embodiments.

[0017] Figure 8 Shows a first structural example of the combiner used in the first and second embodiments.

[0018] Figure 9 Shows a second structural example of the combiner used in the first and second embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] <Content>

[0020] 1. Comparative Example

[0021] 1.1 Structure of Exposure Device 200

[0022] 1.2 Operation of Exposure Device 200

[0023] 1.3 Structure of Laser Device 100

[0024] 1.3.1 First Oscillator MO1 and Second Oscillator MO2

[0025] 1.3.2 First Amplifier PO1 and Second Amplifier PO2

[0026] 1.3.3 First Pulse Expander PS1 and Second Pulse Expander PS2

[0027] 1.3.4 Others

[0028] 1.4 Operation of Laser Device 100

[0029] 1.4.1 First Oscillator MO1 and Second Oscillator MO2

[0030] 1.4.2 First Amplifier PO1 and Second Amplifier PO2

[0031] 1.4.3 First Pulse Expander PS1 and Second Pulse Expander PS2

[0032] 1.4.4 Others

[0033] 1.5 Problems of the Comparative Example

[0034] 2. Laser Device 100a for Splitting the First Amplified Light Bpsa

[0035] 2.1 Structure

[0036] 2.2 Operation

[0037] 2.2.1 Timing Control

[0038] 2.2.2 Energy Control

[0039] 2.3 Function

[0040] 3. Laser Device 100b for Expanding the Pulse Width of the Coupled Light Bpsa1 + Bpsb

[0041] 3.1 Structure

[0042] 3.2 Operation

[0043] 3.3 Function

[0044] 4. Others

[0045] 4.1 Control of Applied Voltage

[0046] 4.2 Structure of the Combiner COM

[0047] 4.3 Supplementary

[0048] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and operations described in the embodiments are not necessarily all essential as the structures and operations of the present disclosure. Furthermore, the same reference numerals are assigned to the same components, and repeated descriptions are omitted.

[0049] 1. Comparative Example

[0050] Figure 1 Shows the structure of the exposure system in the comparative example. The comparative example of the present disclosure is a manner known only to the applicant and not a publicly known example recognized by the applicant himself.

[0051] The exposure system includes a laser device 100 and an exposure device 200. The laser device 100 is configured to output laser B to the exposure device 200.

[0052] 1.1 Structure of the Exposure Device 200

[0053] The exposure device 200 includes an illumination optical system 201 and a projection optical system 202. The illumination optical system 201 illuminates a mask pattern of an unillustrated mask disposed on the mask stage RT using the laser B incident from the laser device 100. The projection optical system 202 reduces and projects the laser B transmitted through the mask and forms an image on an unillustrated workpiece disposed on the workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a resist film.

[0054] 1.2 Operation of the Exposure Device 200

[0055] The exposure device 200 moves the mask stage RT and the workpiece stage WT synchronously in opposite directions in parallel. Thereby, the workpiece is exposed to the laser B reflecting the mask pattern. Through this exposure process, the mask pattern is transferred onto the semiconductor wafer. Then, through multiple processes, electronic devices can be manufactured.

[0056] 1.3 Structure of the Laser Device 100

[0057] Figure 2 Shows the structure of the laser device 100 in the comparative example. The laser device 100 includes a first oscillator MO1 and a second oscillator MO2, a first amplifier PO1 and a second amplifier PO2, a first pulse expander PS1 and a second pulse expander PS2, a combiner COM, and a processor 130.

[0058] 1.3.1 First oscillator MO1 and second oscillator MO2

[0059] The first oscillator MO1 and the second oscillator MO2 have the same structure as each other. The first oscillator MO1 and the second oscillator MO2 are respectively master oscillators including a laser chamber 10, a pair of discharge electrodes 11a and 11b, a narrowbanding module 14, and an output coupling mirror 15.

[0060] The narrowbanding module 14 and the output coupling mirror 15 form a laser resonator. The laser chamber 10 is arranged on the optical path of the laser resonator. Windows 10a and 10b are provided at both ends of the laser chamber 10. The discharge electrodes 11a and 11b are arranged inside the laser chamber 10. The discharge electrode 11a is connected to a pulse power supply 12. Laser gases such as argon or krypton as noble gases, fluorine as a halogen gas, and neon as a buffer gas are enclosed in the laser chamber 10, for example.

[0061] The narrowbanding module 14 includes a prism 14b and a grating 14c. The prism 14b is arranged on the optical path of the light emitted from the window 10a. The grating 14c is arranged on the optical path of the light transmitted through the prism 14b. The output coupling mirror 15 is a partial reflector and is arranged on the optical path of the light emitted from the window 10b.

[0062] 1.3.2 First amplifier PO1 and second amplifier PO2

[0063] The first amplifier PO1 is arranged on the optical path of the seed light B1 output from the first oscillator MO1, and the second amplifier PO2 is arranged on the optical path of the seed light B1 output from the second oscillator MO2. The first amplifier PO1 and the second amplifier PO2 have the same structure. The first amplifier PO1 and the second amplifier PO2 are respectively power oscillators including a laser chamber 20, a pair of discharge electrodes 21a and 21b, a rearview mirror 24, and an output coupling mirror 25.

[0064] The rearview mirror 24 and the output coupling mirror 25 are respectively partial reflectors. The reflectivity of the rearview mirror 24 is set higher than that of the output coupling mirror 25. The rearview mirror 24 and the output coupling mirror 25 form a laser resonator. The laser chamber 20 is arranged on the optical path of the laser resonator. Windows 20a and 20b are provided at both ends of the laser chamber 20. The discharge electrodes 21a and 21b are arranged inside the laser chamber 20. The discharge electrode 21a is connected to a pulse power supply 22. The same laser gas as that in the laser chamber 10 is enclosed in the laser chamber 20.

[0065] Set the discharge directions between the discharge electrodes 11a and 11b and between the discharge electrodes 21a and 21b to the V direction or the -V direction. Set the output direction of the seed light B1 from the output coupling mirror 15 to the Z direction. The V direction and the Z direction are perpendicular to each other, and set the directions perpendicular to both of them to the H direction and the -H direction.

[0066] 1.3.3 First pulse expander PS1 and second pulse expander PS2

[0067] The first pulse expander PS1 is arranged on the optical path of the laser B2 output from the first amplifier PO1, and the second pulse expander PS2 is arranged on the optical path of the laser B2 output from the second amplifier PO2. The first pulse expander PS1 and the second pulse expander PS2 have the same structure. The first pulse expander PS1 and the second pulse expander PS2 respectively include first to fourth concave mirrors 31 to 34 and a beam splitter 35. The first to fourth concave mirrors 31 to 34 are spherical mirrors respectively.

[0068] 1.3.4 Others

[0069] High reflectors 61 and 62 are arranged on the optical paths of the lasers Bps1 and Bps2 output from the first pulse expander PS1 and the second pulse expander PS2 respectively.

[0070] The beam combiner COM is arranged in the space of the optical path including both the lasers Bps1 and Bps2 reflected by the high reflectors 61 and 62 respectively.

[0071] The processor 130 is a processing device including a memory 131 storing a control program and a CPU (central processing unit) 132 executing the control program. The processor 130 is specially configured or programmed to execute various processes included in the present disclosure.

[0072] 1.4 Operation of the laser device 100

[0073] 1.4.1 First oscillator MO1 and second oscillator MO2

[0074] In each of the first oscillator MO1 and the second oscillator MO2, if a high-voltage pulse generated by the pulse power supply 12 is applied to the discharge electrode 11a, discharge is generated inside the laser chamber 10. By the energy of this discharge, the laser medium inside the laser chamber 10 is excited and transferred to a high energy level. When the excited laser medium transfers to a low energy level later, it emits light with a wavelength corresponding to the energy level difference. The light generated inside the laser chamber 10 is emitted to the outside of the laser chamber 10 through the windows 10a and 10b.

[0075] The light emitted from the window 10a of the laser chamber 10 is incident on the grating 14c after the beam width in the H direction is expanded by the prism 14b. The light incident on the grating 14c from the prism 14b is reflected by the multiple grooves of the grating 14c and diffracted in the direction corresponding to the wavelength of the light. The prism 14b reduces the beam width in the H direction of the diffracted light from the grating 14c and returns the light to the laser chamber 10 through the window 10a.

[0076] The output coupling mirror 15 transmits a part of the light emitted from the window 10b of the laser chamber 10 for output, and reflects the other part and returns it to the inside of the laser chamber 10 through the window 10b.

[0077] In this way, the light emitted from the laser chamber 10 reciprocates between the narrowbanding module 14 and the output coupling mirror 15 and is amplified each time it passes through the discharge space inside the laser chamber 10. The light is narrowed each time it is turned back by the narrowbanding module 14. The light that oscillates and is narrowed in this way is output as the seed light B1 from the output coupling mirror 15.

[0078] 1.4.2 First amplifier PO1 and second amplifier PO2

[0079] In each of the first amplifier PO1 and the second amplifier PO2, a high-voltage pulse generated by the pulse power supply 22 is applied to the discharge electrode 21a. The time from when the oscillation trigger signal is sent from the processor 130 to the pulse power supply 12 until when the oscillation trigger signal is sent to the pulse power supply 22 is set so that the moment when the seed light B1 enters the inside of the laser chamber 20 is synchronized with the moment when discharge occurs inside the laser chamber 20.

[0080] The seed light B1 reciprocates between the rearview mirror 24 and the output coupling mirror 25 and is amplified each time it passes through the discharge space inside the laser chamber 20. The amplified laser B2 is output from the output coupling mirror 25.

[0081] 1.4.3 First pulse expander PS1 and second pulse expander PS2

[0082] In each of the first pulse expander PS1 and the second pulse expander PS2, the beam splitter 35 causes a part of the laser B2 incident in the Z direction from the output coupling mirror 25 to be transmitted in the Z direction as the first output light and causes the other part to be reflected in the V direction.

[0083] The first to fourth concave mirrors 31 to 34 sequentially reflect the laser beam B2 reflected by the beam splitter 35 in the V direction, and make it incident on the beam splitter 35 in the V direction. At this time, the beam cross-section of the laser beam B2 incident on the beam splitter 35 in the Z direction is imaged on the beam splitter 35 by the first to fourth concave mirrors 31 to 34 at a ratio of 1:1. The beam splitter 35 reflects a part of the laser beam B2 incident in the V direction from the fourth concave mirror 34 in the Z direction as the second output light, and transmits the other part in the V direction.

[0084] Between the first output light and the second output light, there is a time difference corresponding to the time for the light to travel one round in the delay optical path formed by the first to fourth concave mirrors 31 to 34. By spatially overlapping the first output light and the second output light, it is possible to emit the Expansion laser beams Bps1 and Bps2 with the pulse width reduced.

[0085] By expanding the pulse width of the laser, it is possible to suppress the generation of Speckle speckles on the surface of the semiconductor wafer exposed by the exposure apparatus 200. Speckles refer to the bright and dark spots generated by interference when the laser is scattered to equalize the light intensity distribution of the laser. The intensity of the speckles is represented by the speckle contrast SC, and can be calculated by the following formula.

[0086] SC = (λ 2 / (A·Ω) + τ c / TIS) 1 / 2

[0087] Here, λ is the wavelength, A is the area of the beam cross-section, Ω is the beam divergence angle, τc is the coherence time, and TIS is the pulse width calculated by the following formula.

[0088] TIS = ([∫I(t)dt] 2 ) / (∫I(t) 2 dt)

[0089] Here, t is the time, and I(t) is the light intensity at time t.

[0090] 1.4.4 Others

[0091] The high-reflection mirrors 61 and 62 respectively reflect the laser beams Bps1 and Bps2 toward the combiner COM. The combiner COM couples the laser beams Bps1 and Bps2 by bringing their optical paths closer, and emits the combined light.

[0092] The processor 130 controls the applied voltages of the first oscillator MO1 and the second oscillator MO2 generated by the pulse power supply 12, and the applied voltages of the first amplifier PO1 and the second amplifier PO2 generated by the pulse power supply 22, so that the energy of one pulse of the seed light B1 and the energy of one pulse of the laser B2 respectively become desired values. Further, the processor 130 sends oscillation trigger signals to the pulse power supplies 12 and 22 so that the repetition frequency of the coupled light output from the beam combiner COM becomes a desired value.

[0093] In order to increase the processing speed of the semiconductor wafer in the exposure apparatus 200, it is required to increase the output energy of the laser apparatus 100. As a method for increasing the output energy of the laser apparatus 100, a method of increasing the repetition frequency and a method of increasing the energy of each pulse are considered. However, if the repetition frequency is increased, sometimes the next discharge may occur before the discharge products between the discharge electrodes 11a and 11b and between the discharge electrodes 21a and 21b are removed after one discharge, making the discharge unstable. Or, if the rotation speed of a fan (not shown) is increased in order to remove the discharge products in a short time, the power consumption becomes high. Further, if the repetition frequency is increased, the influence of sound waves becomes large and the light quality deteriorates. On the other hand, if the energy of each pulse is increased, the peak intensity becomes large, and thus the optical elements are likely to deteriorate due to two-photon absorption.

[0094] Therefore, the processor 130 alternately sends oscillation trigger signals to the pulse power supply 12 of the first oscillator MO1 and the second oscillator MO2. If the repetition frequency of the oscillation trigger signals of the first oscillator MO1 and the second oscillator MO2 is set to 6 kHz, the repetition frequency of the coupled light can be set to 12 kHz. Compared with the case where laser oscillation is performed at a repetition frequency of 12 kHz using one oscillator and one amplifier, according to the structure of the comparative example, the first oscillator MO1 and the second oscillator MO2 and the first amplifier PO1 and the second amplifier PO2 perform laser oscillation at a repetition frequency of 6 kHz respectively, so that the possibility of the discharge becoming unstable can be reduced. Further, compared with the case where laser oscillation is performed at a repetition frequency of 6 kHz using one oscillator and one amplifier, according to the structure of the comparative example, even if the peak intensity of the laser is not increased, the energy of the laser per unit time becomes larger, and thus deterioration of the optical elements can be suppressed.

[0095] 1.5 Problems of the Comparative Example

[0096] In the comparative example, the first oscillator MO1, the second oscillator MO2, the first amplifier PO1, and the second amplifier PO2 are required. Since the laser chambers 10 and the narrowbanding modules 14 are respectively included in the first oscillator MO1 and the second oscillator MO2, there are problems that the laser apparatus 100 becomes expensive and the installation space becomes large.

[0097] 2. Laser device 100a that branches the first amplified light Bpsa

[0098] 2.1 Structure

[0099] Figure 3 The structure of the laser device 100a according to the first embodiment is schematically shown. The laser device 100a includes an oscillator MO, a first amplifier POa, a second amplifier POb, a beam splitter BS, a first pulse stretcher PSa, a second pulse stretcher PSb, a combiner COM, and a processor 130. Several high - reflection mirrors for changing the traveling direction of light are shown, but the traveling direction of light and the configuration of the high - reflection mirrors are not limited to the directions and configurations shown in the figure. Figure 3 In, several high - reflection mirrors for changing the traveling direction of light are shown, but the traveling direction of light and the configuration of the high - reflection mirrors are not limited to the directions and configurations shown in the figure.

[0100] The structures of the oscillator MO, the first amplifier POa, the second amplifier POb, the first pulse stretcher PSa, the second pulse stretcher PSb, the combiner COM, and the processor 130 are the same as those of the first oscillator MO1, the first amplifier PO1, the second amplifier PO2, the first pulse stretcher PS1, the second pulse stretcher PS2, the combiner COM, and the processor 130 in the comparative example, respectively.

[0101] The oscillator MO emits pulsed seed light Bmo. The first amplifier POa is arranged on the optical path of the seed light Bmo, amplifies the seed light Bmo, and emits the first amplified light Bpoa. The first pulse stretcher PSa is arranged on the optical path of the first amplified light Bpoa, expands the pulse width of the first amplified light Bpoa, and emits it as the first amplified light Bpsa.

[0102] The beam splitter BS is arranged on the optical path of the first amplified light Bpsa with an expanded pulse width, and splits the first amplified light Bpsa into a first split light Bpsa1 and a second split light Bpsa2. The second split light Bpsa2 has less energy than the first split light Bpsa1. When the first split light Bpsa1 is the light transmitted through the beam splitter BS and the second split light Bpsa2 is the light reflected by the beam splitter BS, it is preferable that the transmittance of the beam splitter BS is 80% or more and 96% or less.

[0103] The second amplifier POb is arranged on the optical path of the second split light Bpsa2, amplifies a part of the second split light Bpsa2, and emits the second amplified light Bpob. The second pulse stretcher PSb is arranged on the optical path of the second amplified light Bpob, expands the pulse width of the second amplified light Bpob, and emits it as the second amplified light Bpsb.

[0104] The total optical path length of the delay optical paths included in the first pulse expander PSa can be equal to the total optical path length of the delay optical paths included in the second pulse expander PSb. The number of stages of the delay optical paths included in the first pulse expander PSa can be equal to the number of stages of the delay optical paths included in the second pulse expander PSb. When the first pulse expander PSa and the second pulse expander PSb include delay optical paths with equal numbers of stages, the combination of the optical path lengths of the delay optical paths included in the first pulse expander PSa can be equal to the combination of the optical path lengths of the delay optical paths included in the second pulse expander PSb. The equality of the optical path lengths of the delay optical paths is not limited to the case of being exactly the same, and also includes the case where the optical path length of the smaller one is 95% or more of the optical path length of the larger one.

[0105] The beam combiner COM is arranged in a space including the optical paths of both the first split light Bpsa1 and the second amplified light Bpsb whose pulse width has been Expansion adjusted. The beam combiner COM emits a combined light Bpsa1 + Bpsb obtained by coupling the optical paths of the first split light Bpsa1 and the second amplified light Bpsb whose pulse width has been Expansion adjusted by bringing them closer. Regarding the structure of the beam combiner COM, refer to Figure 8 and Figure 9 which will be described later.

[0106] Beam splitters with a higher transmittance than reflectance are respectively arranged on the optical paths of the seed light Bmo, the first split light Bpsa1, the second amplified light Bpsb, and the combined light Bpsa1 + Bpsb. Energy sensors Emo, a first energy sensor Epoa, a second energy sensor Epob, and an energy sensor Ecom are respectively arranged on the optical paths of the light reflected by these beam splitters.

[0107] 2.2 Operations

[0108] Figure 4 is a timing diagram showing the oscillation trigger signals and the pulse time waveforms of the laser light of each part of the laser device 100a according to the first embodiment. Figure 4 The horizontal axis of Figure 4 represents time, and

[0109] 2.2.1 Timing Control

[0110] The processor 130 outputs oscillation trigger signals Tmo, Tpoa, and Tpob to the oscillator MO, the first amplifier POa, and the second amplifier POb respectively. The oscillator MO, the first amplifier POa, and the second amplifier POb respectively emit the seed light Bmo, the first amplified light Bpoa, and the second amplified light Bpob according to the oscillation trigger signals Tmo, Tpoa, and Tpob.

[0111] The time T1 from when the oscillation trigger signal Tmo is output from the processor 130 to the oscillator MO until when the oscillation trigger signal Tpoa is output to the first amplifier POa is set so as to optimize parameters such as the energy, energy stability, and spectral line width of the first amplified light Bpoa.

[0112] The pulse time waveform of the first amplified light Bpsa with an extended pulse width can include multiple peaks. The time interval between adjacent peaks can correspond to the time for light to make one round in the delay optical path included in the first pulse expander PSa. However, in the case where the first pulse expander PSa has a structure in which multiple-stage delay optical paths are connected in series, since the combination of the number of round trips of each delay optical path becomes diverse, the pulse time waveform of the first amplified light Bpsa becomes a complex waveform including more peaks. The same applies to the pulse time waveform of the second amplified light Bpsb with an extended pulse width.

[0113] The ratio of the energies of the first split light Bpsa1 and the second split light Bpsa2 is determined by the transmittance of the beam splitter BS.

[0114] The time T2 from when the oscillation trigger signal Tpoa is output from the processor 130 to the first amplifier POa until when the oscillation trigger signal Tpob is output to the second amplifier POb is set so as to make the pulse width of the coupled light Bpsa1 + Bpsb as long as possible. From this viewpoint, the processor 130 controls the amplification timing in the second amplifier POb so that the second amplifier POb amplifies a part included in the latter half of the pulse time waveform of the second split light Bpsa2. The time T2 is longer than the time T1.

[0115] 2.2.2 Energy Control

[0116] The energy of the seed light Bmo is measured by the energy sensor Emo (refer to Figure 3 ). The processor 130 controls the applied voltage HVmo of the oscillator MO based on the measurement result of the energy sensor Emo. Therefore, the energy of the seed light Bmo is controlled within an appropriate range as the seed light of the first amplifier POa.

[0117] Only the part after the oscillation trigger signal Tpob is input to the second amplifier POb in the second split light Bpsa2 incident on the second amplifier POb serves as the seed light of the second amplifier POb. The seed light of the second amplifier POb includes at least one peak part included in the latter half of the pulse time waveform of the second split light Bpsa2. When the energy of the seed light of the second amplifier POb is the same as that of the seed light Bmo of the first amplifier POa, the energy of the second split light Bpsa2 is greater than the energy of the seed light Bmo.

[0118] The pulse time waveform of the coupled light Bpsa1 + Bpsb is equivalent to the combined waveform of the first split light Bpsa1 and the second amplified light Bpsb, and is controlled as follows. The energies of the first split light Bpsa1 and the second amplified light Bpsb are measured by the first energy sensor Epoa and the second energy sensor Epob, respectively. The processor 130 controls the applied voltage HVpoa of the first amplifier POa according to the measurement result of the first energy sensor Epoa, and controls the applied voltage HVpob of the second amplifier POb according to the measurement result of the second energy sensor Epob. Regarding the control of the applied voltage based on the energy measurement result, refer to Figure 7 which will be described later.

[0119] Alternatively, the pulse time waveform of the coupled light Bpsa1 + Bpsb can also be measured by the energy sensor Ecom. The processor 130 can calculate the energy of the first part included in the first half H1 of the pulse time waveform of the coupled light Bpsa1 + Bpsb and the energy of the second part included in the second half H2, and control the applied voltage HVpoa of the first amplifier POa according to the energy of the first part, and control the applied voltage HVpob of the second amplifier POb according to the energy of the second part.

[0120] The first split light Bpsa1 and the second amplified light Bpsb may also have the same energy. Therefore, the energy difference between the first split light Bpsa1 and the second amplified light Bpsb can be smaller than the energy difference between the first split light Bpsa1 and the second split light Bpsa2. In addition, since the first split light Bpsa1 is generated by branching from the first amplified light Bpsa, the energy of the first amplified light Bpsa can be greater than the energy of the second amplified light Bpsb.

[0121] 2.3 Function

[0122] (1) According to the first embodiment, the laser device 100a includes the following components.

[0123] (a) An oscillator MO that emits pulsed seed light Bmo;

[0124] (b) A first amplifier POa that amplifies the seed light Bmo and emits the first amplified light Bpoa;

[0125] (c) A first pulse expander PSa that expands the pulse width of the first amplified light Bpoa;

[0126] (d) A beam splitter BS that splits the first amplified light Bpsa with an expanded pulse width into a first split light Bpsa1 and a second split light Bpsa2 having an energy smaller than that of the first split light Bpsa1;

[0127] (e) A second amplifier POb that amplifies a part of the second split light Bpsa2 and emits the second amplified light Bpob;

[0128] (f) A second pulse stretcher PSb that expands the pulse width of the second amplified light Bpob; and

[0129] (g) A combiner COM that emits a combined light Bpsa1 + Bpsb obtained by coupling the first split light Bpsa1 and the second amplified light Bpsb whose pulse width has been Expansion stretched.

[0130] When splitting the seed light Bmo output from the oscillator MO and making it incident on two amplifiers, in order to make the split seed light Bmo the light amount required for each of the two amplifiers, it is necessary to double the output energy of the oscillator MO, and sometimes the life of the oscillator MO will become shorter. According to the first embodiment, since the first amplified light Bpsa is split after the first amplifier POa, even if there is one oscillator MO, it is possible to obtain the second split light Bpsa2 with sufficient light amount as the seed light of the second amplifier POb while suppressing the load on the oscillator MO. Since there is one oscillator MO, one laser chamber 10 and one narrowbanding module 14 are sufficient, so it is possible to prevent the laser device 100a from becoming expensive or the installation space from becoming large. In addition, since the first amplified light Bpsa is split after the first pulse stretcher PSa, it is possible to reduce the peak intensity of the first amplified light Bpsa incident on the beam splitter BS and suppress the deterioration of optical elements such as the beam splitter BS.

[0131] (2) According to the first embodiment, the laser device 100a further includes a processor 130. The processor 130 controls the amplification timing in the second amplifier POb so that the second amplifier POb amplifies a part included in the latter half of the pulse time waveform of the second split light Bpsa2.

[0132] As a result, the second amplified light Bpsb is obtained by amplifying a part that is a part of the second split light Bpsa2 and is included in the latter half of the pulse time waveform of the second split light Bpsa2. Therefore, the pulse width of the combined light Bpsa1 + Bpsb can be increased when coupled with the first split light Bpsa1. The Speckle contrast SC can be reduced by increasing the pulse width.

[0133] (3) According to the first embodiment, the energy difference between the first split light Bpsa1 and the second amplified light Bpsb whose pulse width has been expanded is smaller than the energy difference between the first split light Bpsa1 and the second split light Bpsa2.

[0134] As a result, it is possible to reduce the energy difference between the first half and the second half of the coupled light Bpsa1 + Bpsb.

[0135] (4) According to the first embodiment, the laser device 100a includes a processor 130. The processor 130 is configured to output an oscillation trigger signal Tmo, Tpoa, and Tpob to the oscillator MO, the first amplifier POa, and the second amplifier POb, respectively. The time T1 from when the oscillation trigger signal Tmo is output to the oscillator MO until the oscillation trigger signal Tpoa is output to the first amplifier POa is shorter than the time T2 from when the oscillation trigger signal Tpoa is output to the first amplifier POa until the oscillation trigger signal Tpob is output to the second amplifier POb.

[0136] Accordingly, by staggering the amplification timing between the first amplifier POa and the second amplifier POb, it is possible to increase the pulse width of the coupled light Bpsa1 + Bpsb when the first split light Bpsa1 and the second amplified light Bpsb are coupled.

[0137] (5) According to the first embodiment, the energy of the second split light Bpsa2 is greater than the energy of the seed light Bmo.

[0138] As a result, since the energy of the second split light Bpsa2 is large, a part of the second split light Bpsa2 can have a sufficient light amount to serve as the seed light of the second amplifier POb.

[0139] (6) According to the first embodiment, the laser device 100a includes: a first energy sensor Epoa that measures the energy of the first split light Bpsa1; a second energy sensor Epob that measures the energy of the second amplified light Bpsb with an extended pulse width; and a processor 130. The processor 130 controls the applied voltage HVpoa of the first amplifier POa based on the measurement result of the first energy sensor Epoa, and controls the applied voltage HVpob of the second amplifier POb based on the measurement result of the second energy sensor Epob.

[0140] Accordingly, by measuring the first split light Bpsa1 and the second amplified light Bpsb respectively and independently controlling the applied voltages HVpoa and HVpob of the first amplifier POa and the second amplifier POb, it is possible to accurately control the pulse time waveform of the coupled light Bpsa1 + Bpsb and achieve sufficient energy stability. In addition, the dose representing the energy of the laser irradiated on a part of the semiconductor wafer can also be stabilized.

[0141] (7)According to the first embodiment, the laser device 100a includes an energy sensor Ecom that measures the pulse time waveform of the coupled light Bpsa1 + Bpsb and a processor 130. The processor 130 calculates the energy of the first part included in the first half H1 of the pulse time waveform and the energy of the second part included in the second half H2 of the pulse time waveform, controls the applied voltage HVpoa of the first amplifier POa according to the energy of the first part, and controls the applied voltage HVpob of the second amplifier POb according to the energy of the second part.

[0142] Thereby, the information required to independently control the applied voltages HVpoa and HVpob of the first amplifier POa and the second amplifier POb can be obtained using one energy sensor Ecom. Thereby, the pulse time waveform of the coupled light Bpsa1 + Bpsb can be controlled with high precision, and sufficient energy stability can be achieved. In addition, the dose can also be stabilized.

[0143] (8)According to the first embodiment, the Expansion energy of the first amplified light Bpsa with the Expansion pulse width is larger than the energy of the second amplified light Bpsb with the

[0144] pulse width.

[0145] (9)According to the first embodiment, the first split light Bpsa1 is the light transmitted through the beam splitter BS, the second split light Bpsa2 is the light reflected by the beam splitter BS, and the transmittance of the beam splitter BS is 80% or more and 96% or less.

[0146] Thereby, the first split light Bpsa1 can be made to have a sufficient light amount as a part of the coupled light Bpsa1 + Bpsb, and a part of the second split light Bpsa2 can be made to have a sufficient light amount as the seed light of the second amplifier POb.

[0147] (10)According to the first embodiment, the optical path lengths of the delay optical paths included in the first pulse expander PSa and the second pulse expander PSb are equal to each other.

[0148] Thereby, the pulse time widths of the first split light Bpsa1 and the second amplified light Bpsb can be made equal.

[0149] (11)According to the first embodiment, the first pulse expander PSa and the second pulse expander PSb each include delay optical paths with a stage number of 2 or more and equal to each other.

[0150] Thus, it is possible to make the speckle contrast SC of the first split light Bpsa1 and the second amplified light Bpsb equal.

[0151] (12) According to the first embodiment, the combination of the optical path lengths of the delay optical paths included in the first pulse expander PSa is equal to the combination of the optical path lengths of the delay optical paths included in the second pulse expander PSb.

[0152] Thus, it is possible to make the pulse time widths of the first split light Bpsa1 and the second amplified light Bpsb and Speckle Contrast SC equal.

[0153] (13) According to the first embodiment, the combiner COM couples by bringing the optical paths of the first split light Bpsa1 and the second amplified light Bpsb whose pulse widths have been adjusted closer to each other, and emits the coupled light Bpsa1 + Bpsb. Expansion Thus, even if the wavelengths and polarization directions of the first split light Bpsa1 and the second amplified light Bpsb are the same, it is possible to generate the coupled light Bpsa1 + Bpsb.

[0154] In other respects, the first embodiment is the same as the comparative example.

[0155] Regarding other aspects, the first embodiment is the same as the comparative example.

[0156] 3. Laser device 100b for expanding the pulse width of the coupled light Bpsa1 + Bpsb

[0157] 3.1 Structure

[0158] Figure 5 Schematically shows the structure of the laser device 100b according to the second embodiment. The laser device 100b includes a third pulse expander PSc disposed on the optical path of the coupled light Bpsa1 + Bpsb. The third pulse expander PSc expands the pulse width of the coupled light Bpsa1 + Bpsb and emits it as the coupled light Bpsc.

[0159] In the second embodiment, a third pulse stretcher PSc is added. Therefore, the number of stages of the delay optical paths of the first pulse stretcher PSA and the second pulse stretcher PSb is preferably as small as possible with 1 as the lower limit. By including the delay optical path of the number of stages that needs to be added in addition to the delay optical paths of the first pulse stretcher PSA and the second pulse stretcher PSb in the third pulse stretcher PSc, the number of delay optical paths included in the laser device 100b can be reduced. Therefore, it is preferable that the number of stages of the delay optical paths included in each of the first pulse stretcher PSA and the second pulse stretcher PSb is equal to or less than the number of stages of the delay optical path included in the third pulse stretcher PSc. In addition, it is preferable that the number of stages of the delay optical paths included in the first pulse stretcher PSA and the second pulse stretcher PSb are equal to each other. Further, it is preferable that the difference in the optical path lengths between the first pulse stretcher PSA and the second pulse stretcher PSb is smaller than both the difference in the optical path lengths between the first pulse stretcher PSA and the third pulse stretcher PSc and the difference in the optical path lengths between the second pulse stretcher PSb and the third pulse stretcher PSc.

[0160] It is preferable that the optical path lengths of each of the first pulse stretcher PSA and the second pulse stretcher PSb are longer than the optical path length of the delay optical path included in the third pulse stretcher PSc. When the third pulse stretcher PSc includes multiple stages of delay optical paths, it is preferable that the optical path lengths of each of the first pulse stretcher PSA and the second pulse stretcher PSb are longer than the optical path length of the longest delay optical path included in the delay optical paths included in the third pulse stretcher PSc.

[0161] 3.2 Operation

[0162] Figure 6 It is a timing chart showing the oscillation trigger signals of each part of the laser device 100b of the second embodiment and the pulse time waveform of the laser. Since the optical path length of the first pulse stretcher PSA is longer than the optical path length of the third pulse stretcher PSc, the time T3 for the first amplified light Bpoa to go around the delay optical path included in the first pulse stretcher PSA is longer than the time T4 for the coupled light Bpsa1 + Bpsb to go around the delay optical path included in the third pulse stretcher PSc.

[0163] Since the optical path lengths of each of the first pulse stretcher PSA and the second pulse stretcher PSb are long, the time T2 from when the oscillation trigger signal Tpoa is output from the processor 130 to the first amplifier POa until the oscillation trigger signal Tpob is output to the second amplifier POb can be extended. It is preferable that the time T2 is longer than the time T3.

[0164] 3.3 Function

[0165] (14)According to the second embodiment, in addition to the components of the laser device 100a, the laser device 100b further includes a third pulse stretcher PSc that expands the pulse width of the combined coupling light Bpsa1 + Bpsb.

[0166] Thereby, instead of adding the third pulse stretcher PSc, the optical path lengths and the number of stages of the first pulse stretcher PSa and the second pulse stretcher PSb can be reduced respectively. Therefore, the total optical path length and the total number of stages of the first pulse stretcher PSa, the second pulse stretcher PSb, and the third pulse stretcher PSc can be reduced.

[0167] (15)According to the second embodiment, the first pulse stretcher PSa and the second pulse stretcher PSb each include a delay optical path having a number of stages less than or equal to the number of stages of the delay optical path included in the third pulse stretcher PSc.

[0168] Thereby, the number of stages of the delay optical paths of the first pulse stretcher PSa and the second pulse stretcher PSb is further reduced, and thus the total number of stages of the delay optical paths of the first pulse stretcher PSa, the second pulse stretcher PSb, and the third pulse stretcher PSc can be reduced.

[0169] (16)According to the second embodiment, the first pulse stretcher PSa and the second pulse stretcher PSb each include delay optical paths having equal numbers of stages.

[0170] Thereby, the speckle contrast SC of the first split light Bpsa1 and the second amplified light Bpsb can be made equal.

[0171] (17)According to the second embodiment, the difference in optical path length between the first pulse stretcher PSa and the second pulse stretcher PSb is smaller than both the difference in optical path length between the first pulse stretcher PSa and the third pulse stretcher PSc and the difference in optical path length between the second pulse stretcher PSb and the third pulse stretcher PSc.

[0172] It is considered that the structure of the first pulse stretcher PSa suitable for combination with the third pulse stretcher PSc is also suitable as the structure of the second pulse stretcher PSb. By reducing the difference in optical path length between the first pulse stretcher PSa and the second pulse stretcher PSb, the pulse time waveforms of both the first split light Bpsa1 and the second amplified light Bpsb with expanded pulse width can be made into ideal waveforms.

[0173] (18)According to the second embodiment, the optical path length of the first pulse stretcher PSa and the optical path length of the second pulse stretcher PSb are each longer than the optical path length of the third pulse stretcher PSc.

[0174] Thus, the time difference between the first split light Bpsa1 and the second amplified light Bpsb can be increased, and the pulse width of the coupled light Bpsa1 + Bpsb can be increased.

[0175] (19) According to the second embodiment, the laser device 100b includes a processor 130. The processor 130 is configured to output an oscillation trigger signal Tpoa and a Tpob to the first amplifier POa and the second amplifier POb, respectively. The time T2 from when the oscillation trigger signal Tpoa is output to the first amplifier POa until when the oscillation trigger signal Tpob is output to the second amplifier POb is longer than the time T3 for the first amplified light Bpoa to travel one round along the delay optical path included in the first pulse expander PSa.

[0176] Accordingly, by significantly staggering the amplification timing in the first amplifier POa and the second amplifier POb, the pulse width of the coupled light Bpsa1 + Bpsb can be increased when the first split light Bpsa1 and the second amplified light Bpsb are coupled.

[0177] In other aspects, the second embodiment is the same as the first embodiment.

[0178] 4. Others

[0179] 4.1 Control of the applied voltage

[0180] Figure 7 is a flowchart of the control of the applied voltage executed by the processor 130 in the first and second embodiments. In Figure 7 the following five controls are summarized and described as the control of the applied voltage HV based on the energy E of the laser.

[0181] (a) Control of the applied voltage HVmo of the oscillator MO based on the energy of the seed light Bmo measured by the energy sensor Emo

[0182] (b) Control of the applied voltage HVpoa of the first amplifier POa based on the energy of the first split light Bpsa1 measured by the first energy sensor Epoa

[0183] (c) Control of the applied voltage HVpob of the second amplifier POb based on the energy of the second amplified light Bpob measured by the second energy sensor Epob

[0184] (d) Control of the applied voltage HVpoa of the first amplifier POa based on the energy of the first part of the coupled light Bpsa1 + Bpsb measured by the energy sensor Ecom

[0185] (e) Control of the application voltage HVpob of the second amplifier POb based on the energy of the second part of the coupled light Bpsa1 + Bpsb measured by the energy sensor Ecom

[0186] In S1, the processor 130 obtains the result of measuring the energy E of the laser while changing the application voltage HV, and calculates the slope k of the energy E with respect to the application voltage HV. This calculation is performed at regular intervals.

[0187] In S2, the processor 130 outputs an oscillation trigger signal to emit one pulse of the laser.

[0188] In S3, the processor 130 obtains the measurement result of the energy E of the laser and calculates the difference ΔE from the target value.

[0189] In S4, the processor 130 calculates the correction amount ΔHV of the application voltage HV by the following formula.

[0190] ΔHV = ΔE / k

[0191] In S5, the processor 130 corrects the application voltage HV of the next pulse using the correction amount ΔHV.

[0192] After S5, the processor 130 returns the process to S2. As described above, the application voltage HV is controlled to make the energy E of the laser approach the target value.

[0193] 4.2 Structure of the beam combiner COM

[0194] Figure 8 Shows a first structural example of the beam combiner COM used in the first and second embodiments. The beam combiner COM of the first structural example includes a prism mirror 51 coated with a high reflection film 511.

[0195] The first split light Bpsa1 and the second amplified light Bpsb are incident on the beam combiner COM through optical paths perpendicular to each other. The high reflection surface coated with the high reflection film 511 is inclined 45 degrees with respect to both the first split light Bpsa1 and the second amplified light Bpsb. The high reflection surface of the prism mirror 51 forms an angle of 45 degrees or less with another surface to form a ridge line 510. The second amplified light Bpsb does not enter the prism mirror 51 but passes through a position as close as possible to the ridge line 510 of the prism mirror 51. The first split light Bpsa1 is incident on a position as close as possible to the ridge line 510 in the high reflection surface and is reflected in a direction parallel to the second amplified light Bpsb. Thus, the first split light Bpsa1 and the second amplified light Bpsb can be made close to each other.

[0196] Figure 9Shows a second structural example of the beam combiner COM used in the first and second embodiments. The beam combiner COM of the second structural example has the following structure: A high-reflection film 521 is coated on a part of the planar substrate 52 that is transparent to the second amplified light Bpsb, and an antireflection film is coated on the other part.

[0197] The first split light Bpsa1 and the second amplified light Bpsb are incident on the planar substrate 52 through optical paths perpendicular to each other. The high-reflection surface coated with the high-reflection film 521 is inclined 45 degrees with respect to both the first split light Bpsa1 and the second amplified light Bpsb. The second amplified light Bpsb transmits through the following position: This position is located in the part coated with the antireflection film and as close as possible to the boundary with the part coated with the high-reflection film 521. The first split light Bpsa1 is incident on the following position and is reflected in a direction parallel to the second amplified light Bpsb: This position is located in the part coated with the high-reflection film 521 and as close as possible to the boundary with the part coated with the antireflection film. Thereby, the first split light Bpsa1 and the second amplified light Bpsb can be made close to each other.

[0198] 4.3 Supplement

[0199] The above description is not restrictive 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 to use the embodiments of the present disclosure in combination.

[0200] Unless otherwise clearly stated, the terms used throughout this specification and the claims should be interpreted as "non-limiting". For example, terms such as "comprising", "having", "including", and "possessing" should be interpreted as "not excluding the existence of components other than the recited components". In addition, the modifier "one" should be interpreted as "at least one" or "one or more". Furthermore, 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". Moreover, it should be interpreted as also including combinations with components other than "A", "B", and "C".

Claims

1. A laser device comprising: an oscillator that emits pulsed seed light; a first amplifier, which amplifies the seed light to emit a first amplified light; A first pulse stretcher, which stretches the pulse width of the first amplified light; a beam splitter for splitting the first amplified light whose pulse width is extended into a first split light and a second split light with less energy than the first split light; a second amplifier that amplifies a portion of the second split light to emit a second amplified light; a second pulse stretcher that stretches the pulse width of the second amplified light; and The beam combiner emits coupled light obtained by coupling the first split light and the second amplified light whose pulse width is extended.

2. The laser device according to claim 1, wherein: The laser device also includes a processor, The processor controls the timing of amplification in the second amplifier so that the second amplifier amplifies the portion included in the second half of the pulse time waveform of the second divided light.

3. The laser device according to claim 2, wherein: The energy difference between the first split light and the second amplified light having a pulse width extended is smaller than the energy difference between the first split light and the second split light.

4. The laser device according to claim 1, wherein: The laser device also includes a processor, which is configured to output an oscillation trigger signal to the oscillator and the first amplifier and the second amplifier, respectively, and the time from when the oscillation trigger signal is output to the oscillator to when the oscillation trigger signal is output to the first amplifier is shorter than the time from when the oscillation trigger signal is output to the first amplifier to when the oscillation trigger signal is output to the second amplifier.

5. The laser device according to claim 1, wherein: The energy of the second split light is greater than the energy of the seed light.

6. The laser device according to claim 1, wherein: The laser device also has: a first energy sensor for measuring the energy of the first split light; a second energy sensor for measuring the energy of the second amplified light whose pulse width has been extended; as well as processor, The processor controls an applied voltage of the first amplifier based on a measurement result of the first energy sensor, and controls an applied voltage of the second amplifier based on a measurement result of the second energy sensor.

7. The laser device according to claim 1, wherein: The laser device also has: An energy sensor that measures a pulse time waveform of the coupled light; as well as processor, The processor calculates the energy of a first part included in the first half of the pulse time waveform and the energy of a second part included in the second half of the pulse time waveform, controls the applied voltage of the first amplifier based on the energy of the first part, and controls the applied voltage of the second amplifier based on the energy of the second part.

8. The laser device according to claim 1, wherein: The energy of the first amplified light whose pulse width is extended is greater than the energy of the second amplified light whose pulse width is extended.

9. The laser device according to claim 1, wherein: The first split light is light transmitted through the beam splitter, The second split light is light reflected by the beam splitter, The transmittance of the beam splitter is 80% or more and 96% or less.

10. The laser device according to claim 1, wherein: The optical path lengths of the delay optical paths included in the first pulse stretcher and the second pulse stretcher are equal to each other.

11. The laser device according to claim 1, wherein: The first pulse stretcher and the second pulse stretcher each include delay optical paths of which the number of stages is greater than or equal to each other.

12. The laser device according to claim 11, wherein: A combination of optical path lengths of the delay optical paths included in the first pulse stretcher is equal to a combination of optical path lengths of the delay optical paths included in the second pulse stretcher.

13. The laser device according to claim 1, wherein: The beam combiner couples the first split light and the second amplified light whose pulse width has been extended by bringing the first split light and the second amplified light close to each other in optical path, thereby emitting the coupled light.

14. The laser device according to claim 1, wherein: The laser device further includes a third pulse stretcher that stretches the pulse width of the coupled light.

15. The laser device according to claim 14, wherein: The first pulse stretcher and the second pulse stretcher each include a delay optical path having a number of stages less than the number of stages of the delay optical path included in the third pulse stretcher.

16. The laser device according to claim 15, wherein: The first pulse stretcher and the second pulse stretcher each include the delay optical paths of equal numbers to each other.

17. The laser device according to claim 14, wherein: A difference in optical path length between the first pulse stretcher and the second pulse stretcher is smaller than a difference in optical path length between the first pulse stretcher and the third pulse stretcher and a difference in optical path length between the second pulse stretcher and the third pulse stretcher.

18. The laser device according to claim 14, wherein: The optical path length of the first pulse stretcher and the optical path length of the second pulse stretcher are respectively longer than the optical path length of the third pulse stretcher.

19. The laser device according to claim 14, wherein: The laser device further comprises a processor, The processor is configured to output an oscillation trigger signal to the first amplifier and the second amplifier respectively. The time from when the oscillation trigger signal is output to the first amplifier to when the oscillation trigger signal is output to the second amplifier is longer than the time it takes for the first amplified light to travel around a delay optical path included in the first pulse stretcher.

20. A method for manufacturing an electronic device, comprising the following steps: generating laser light by means of a laser device; outputting the laser light to an exposure device; and In order to manufacture the electronic device, the laser light is exposed on a photosensitive substrate in the exposure device. The laser device comprises: an oscillator that emits pulsed seed light; a first amplifier, which amplifies the seed light to emit a first amplified light; A first pulse stretcher, which stretches the pulse width of the first amplified light; a beam splitter for splitting the first amplified light whose pulse width is extended into a first split light and a second split light with less energy than the first split light; a second amplifier that amplifies a portion of the second split light to emit a second amplified light; a second pulse stretcher that stretches the pulse width of the second amplified light; and The beam combiner emits coupled light obtained by coupling the first split light and the second amplified light whose pulse width is extended.

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