Narrow band laser device and method for manufacturing electronic device

Abstract

A narrowband laser device is provided with: a laser resonator including an output coupling mirror and a narrowband module including a prism and a grating, the reflecting surface of the grating having a concave surface; a laser chamber that includes a pair of discharge electrodes and is disposed on an optical path of the laser resonator; a power source that applies a high-voltage pulse to the discharge electrode, the repetition frequency of the high-voltage pulse being variable; the wave surface regulator comprises an output coupling mirror; the spectrum detector is used for measuring the spectral line width of the pulse laser output from the output coupling mirror; and a processor that controls the wavefront regulator according to the measured spectral line width.

Description

Technical Field

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

[0002] In recent years, in semiconductor exposure devices, as semiconductor integrated circuits become smaller and more highly integrated, there is a demand for higher resolution. Therefore, the wavelength of light emitted from the exposure light source is being shortened. For example, as a gas laser device for exposure, a KrF excimer laser device that outputs a laser with a wavelength of about 248nm and an ArF excimer laser device that outputs a laser with a wavelength of about 193nm are used.

[0003] The spectral line width of the natural oscillation light of the KrF excimer laser device and the ArF excimer laser device is 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 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 degree 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. A gas laser device with a narrowed spectral line width is called a narrowed gas laser device.

[0004] Prior art literature

[0005] Patent Literature

[0006] [Patent Document 1] U.S. Patent Application Publication No. 2007 / 014326

[0007] [Patent Document 2] U.S. Patent No. 6526086 Summary of the invention

[0008] A narrowband laser device according to one aspect of the present disclosure comprises: a laser resonator, which includes an output coupling mirror and a narrowband module, the narrowband module includes a prism and a grating, and the reflection surface of the grating is concave; a laser cavity, which includes a pair of discharge electrodes and is arranged on the optical path of the laser resonator; a power supply, which applies high-voltage pulses to the discharge electrodes, and the repetition frequency of the high-voltage pulses is variable; a wavefront modifier, which includes an output coupling mirror; a spectrum detector, which is used to measure the spectral line width of the pulsed laser output from the output coupling mirror; and a processor, which controls the wavefront modifier according to the measured spectral line width.

[0009] A method for manufacturing an electronic device according to one aspect of the present disclosure includes the following steps: generating a pulsed laser using a narrowband laser device; outputting the pulsed laser to an exposure device; and exposing the pulsed laser on a photosensitive substrate in the exposure device to manufacture the electronic device, wherein the narrowband laser device comprises: a laser resonator including an output coupling mirror and a narrowband module, the narrowband module including a prism and a grating, the reflection surface of the grating being concave; a laser chamber including a pair of discharge electrodes arranged on an optical path of the laser resonator; a power supply applying a high voltage pulse to the discharge electrode, the repetition frequency of the high voltage pulse being variable; a wavefront modulator including an output coupling mirror; a spectrum detector measuring the spectral line width of the pulsed laser output from the output coupling mirror; and a processor controlling the wavefront modulator based on the measured spectral line width. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings, merely as examples.

[0011] Figure 1 The structure of an exposure system in a comparative example is schematically shown.

[0012] Figure 2 The structure of a laser device according to a comparative example is schematically shown.

[0013] Figure 3 This is a graph showing an example of output timing of pulsed laser light.

[0014] Figure 4 : is a flowchart showing the procedure of line width control in a comparative example.

[0015] Figure 5 An example of a spectrum waveform for explaining E95 is shown.

[0016] Figure 6 The measurement results of the variation of the spectral line width according to the repetition frequency of the pulsed laser in the comparative example are shown.

[0017] Figure 7 The simulation results of the variation of the spectral line width according to the repetition frequency of the pulsed laser in the comparative example are shown.

[0018] Figure 8 The structure of the laser device according to the first embodiment is schematically shown.

[0019] Fig. 9 The structure of the narrowband module in the first embodiment is shown.

[0020] Fig.10 The structure of the wave front adjuster in the first embodiment is shown.

[0021] Fig.11: is a graph showing the simulation results of the spectral line width of the pulsed laser corresponding to the g-parameters of the grating and the wavefront modifier.

[0022] Fig.12 The measurement results of the variation of the line width according to the repetition frequency of the pulsed laser light in the first embodiment are shown.

[0023] Fig.13 The simulation results of the variation of the line width according to the repetition frequency of the pulsed laser in the first embodiment are shown.

[0024] Fig.14 is a graph showing the result of simulating the relationship between the g parameter of the grating and the pulse energy.

[0025] Fig.15 The structure of the laser device in the second embodiment is schematically shown.

[0026] Fig.16 The structure of the laser device in the third embodiment is schematically shown.

[0027] Fig.17 Shown from Fig.16 Observe from different directions Fig.16 The case of the power oscillator shown. DETAILED DESCRIPTION

[0028] <Content>

[0029] 1. Comparative Example

[0030] 1.1 Structure of Exposure Device 100

[0031] 1.2 Operation of Exposure Device 100

[0032] 1.3 Structure of the laser device 1

[0033] 1.3.1 Laser resonator

[0034] 1.3.2 Monitoring module 16

[0035] 1.4 Operation of the laser device 1

[0036] 1.4.1 Laser Control Processor 30

[0037] 1.4.2 Laser Oscillation

[0038] 1.4.3 Monitoring module 16

[0039] 1.4.4 Sudden Oscillation

[0040] 1.4.5 Spectral line width control

[0041] 1.5 Issues of Comparative Example

[0042] 2. Laser device 1a including concave grating 14c

[0043] 2.1 Structure

[0044] 2.2 Grating 14c g parameter g_Grating

[0045] 2.3 g parameter g_EFM of the wavefront regulator 15a

[0046] 2.4g parameter and the relationship between the spectral line width

[0047] Relationship between 2.5g parameters and pulse energy

[0048] 2.6 Function

[0049] 3. Laser device 1b including master oscillator MO and power oscillator PO

[0050] 3.1 Structure

[0051] 3.2 Action

[0052] 3.2.1 Laser control processor 30

[0053] 3.2.2 Main Oscillator MO

[0054] 3.2.3 Power Oscillator PO

[0055] 3.3 Function

[0056] 4. Laser device 1c including a ring resonator

[0057] 4.1 Structure

[0058] 4.2 Actions

[0059] 4.3 Function

[0060] 5. Others

[0061] Hereinafter, the 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 required as the structures and actions of the present disclosure. In addition, the same reference numerals are marked on the same constituent elements, and repeated descriptions are omitted.

[0062] 1. Comparative Example

[0063] Figure 1 The configuration of the exposure system in the comparative example is schematically shown. The comparative example of the present disclosure is a method that the applicant recognizes to be known only by the applicant, and is not a publicly known example recognized by the applicant himself.

[0064] The exposure system includes a laser device 1 and an exposure device 100. The laser device 1 includes a laser control processor 30. The laser control processor 30 is a processing device including a memory 302 storing a control program and a CPU (central processing unit) 301 that executes the control program. The laser control processor 30 is specially configured or programmed to execute various processes included in the present disclosure. The laser control processor 30 is equivalent to the processor in the present disclosure. The laser device 1 is equivalent to the narrowband laser device in the present disclosure, and is configured to output a pulsed laser toward the exposure device 100.

[0065] 1.1 Structure of Exposure Device 100

[0066] The exposure device 100 includes an illumination optical system 101 , a projection optical system 102 , and an exposure control processor 110 .

[0067] The illumination optical system 101 illuminates a reticle pattern of a reticle (not shown) arranged on the reticle stage RT using the pulsed laser light incident from the laser device 1 .

[0068] The projection optical system 102 projects the pulsed laser light transmitted through the mask in a reduced size so as to form an image on a workpiece (not shown) arranged on a workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a resist film.

[0069] The exposure control processor 110 is a processing device including a memory 112 storing a control program and a CPU 111 executing the control program. The exposure control processor 110 is specially configured or programmed to perform various processes included in the present disclosure. The exposure control processor 110 uniformly controls the exposure device 100, and transmits and receives various data and various signals to and from the laser control processor 30.

[0070] 1.2 Operation of Exposure Device 100

[0071] The exposure control processor 110 sends the setting data of the target line width and the target pulse energy and the trigger signal to the laser control processor 30. The laser control processor 30 controls the laser device 1 according to these data and signals.

[0072] Exposure control processor 110 causes reticle stage RT and workpiece stage WT to move in parallel in opposite directions in synchronization with each other, thereby exposing the workpiece with pulsed laser light reflecting the reticle pattern.

[0073] Through such an exposure process, the mask pattern is transferred to the semiconductor wafer. Then, through multiple processes, an electronic device can be manufactured.

[0074] 1.3 Structure of the laser device 1

[0075] Figure 2 The structure of the laser device 1 of the comparative example is schematically shown. The laser device 1 includes a laser chamber 10 , a discharge electrode 11 a , a power supply 12 , a narrowband module 14 , a wavefront adjuster 15 a , a monitoring module 16 , and a laser control processor 30 . The laser device 1 can be connected to an exposure device 100 .

[0076] 1.3.1 Laser resonator

[0077] The wavefront adjuster 15a includes an output coupling mirror, and the output coupling mirror and the narrowband module 14 constitute 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. A discharge electrode 11a and a discharge electrode not shown in the figure that is paired therewith are arranged inside the laser chamber 10. The discharge electrode not shown in the figure is located at a position overlapping with the discharge electrode 11a in the direction of the V axis perpendicular to the paper surface. The direction of the V axis is equivalent to the first direction in the present disclosure. For example, a laser gas is sealed in the laser chamber 10, and the laser gas includes argon gas or krypton gas as a rare gas, fluorine gas as a halogen gas, neon gas as a buffer gas, etc.

[0078] The power source 12 includes a switch 13 and is connected to the discharge electrode 11 a and a charger (not shown).

[0079] The narrowband module 14 includes a plurality of prisms 14a and 14b and a grating 14c. The prisms 14a and 14b are sequentially arranged on the optical path of the light emitted from the window 10a. The surfaces of the prisms 14a and 14b through which the light enters and exits are parallel to the V axis.

[0080] The grating 14c is disposed on the optical path of the light transmitted through the prisms 14a and 14b. The grooves of the grating 14c are oriented in parallel with the V axis.

[0081] The wavefront adjuster 15a includes a cylindrical convex lens 15b and a cylindrical concave lens 15c.

[0082] The cylindrical convex lens 15b is a cylindrical plano-convex lens including a flat surface on which a partial reflection film is formed and a convex surface on the opposite side of the flat surface. The focal axis of the cylindrical convex lens 15b is parallel to the V axis.

[0083] The cylindrical concave lens 15c is a cylindrical plano-concave lens including a flat surface and a concave surface on the opposite side of the surface. The focal axis of the cylindrical concave lens 15c is parallel to the V axis. The cylindrical concave lens 15c is supported by a linear stage 15d. The linear stage 15d includes: an actuator (not shown) that moves the cylindrical concave lens 15c along the optical path of the laser resonator; and a driver (not shown) that drives the actuator according to a control signal from the laser control processor 30.

[0084] The convex surface of cylindrical convex lens 15b and the concave surface of cylindrical concave lens 15c are opposite to each other. The flat surface of cylindrical convex lens 15b constitutes an output coupling mirror, and the convex surface of cylindrical convex lens 15b and cylindrical concave lens 15c constituting wavefront adjuster 15a are located between the output coupling mirror and laser chamber 10.

[0085] Here, the case where the flat surface of the cylindrical convex lens 15b constitutes the output coupling mirror is described, but the cylindrical convex lens and the output coupling mirror may be constituted by different optical components. That is, the wavefront adjuster 15a may include an output coupling mirror constituted by a flat substrate or a wedge-shaped substrate and having a partial reflection film, and a cylindrical convex lens located between the output coupling mirror and the laser chamber 10 and not having a partial reflection film, instead of the cylindrical convex lens 15b.

[0086] 1.3.2 Monitoring module 16

[0087] The monitoring module 16 is located on the optical path of the pulse laser output from the output coupling mirror included in the wavefront adjuster 15a. The monitoring module 16 includes beam splitters 16a and 16b, an energy detector 16c, and a spectrum detector 16d.

[0088] The beam splitter 16a is located on the optical path of the pulsed laser output from the output coupling mirror. The beam splitter 16a is configured to transmit a portion of the pulsed laser with high transmittance toward the exposure device 100 and reflect the other portion. The beam splitter 16b is located on the optical path of the pulsed laser reflected by the beam splitter 16a. The energy detector 16c is located on the optical path of the pulsed laser reflected by the beam splitter 16b. The spectrum detector 16d is located on the optical path of the pulsed laser transmitted through the beam splitter 16b. The spectrum detector 16d includes an etalon and a light distribution sensor, which are not shown.

[0089] 1.4 Operation of the laser device 1

[0090] 1.4.1 Laser Control Processor 30

[0091] The laser control processor 30 transmits setting data of the applied voltage to the discharge electrode 11a to the power supply 12 based on the setting data of the target pulse energy received from the exposure control processor 110. The laser control processor 30 transmits a control signal to the linear stage 15d included in the wavefront adjuster 15a based on the setting data of the target line width received from the exposure control processor 110. In addition, the laser control processor 30 transmits an oscillation trigger signal based on the trigger signal received from the exposure control processor 110 to the switch 13 included in the power supply 12.

[0092] 1.4.2 Laser Oscillation

[0093] The switch 13 is turned on when receiving an oscillation trigger signal from the laser control processor 30. When the switch 13 is turned on, the power source 12 generates a high voltage pulse using electric energy charged in a charger (not shown) and applies the high voltage pulse to the discharge electrode 11a.

[0094] When a high voltage pulse is applied to the discharge electrode 11a, discharge occurs inside the laser chamber 10. The energy of the discharge excites the laser medium in the laser chamber 10 and transfers to a high energy level. When the excited laser medium subsequently transfers to a low energy level, it emits light of a wavelength corresponding to the energy level difference.

[0095] Light generated inside the laser chamber 10 is emitted to the outside of the laser chamber 10 through the windows 10a and 10b. The light emitted from the window 10a of the laser chamber 10 is beam-widened by the prisms 14a and 14b and then enters the grating 14c.

[0096] The light incident on the grating 14 c from the prisms 14 a and 14 b is reflected by the plurality of grooves of the grating 14 c and diffracted in a direction corresponding to the wavelength of the light.

[0097] The prisms 14a and 14b reduce the beam width of the diffracted light from the grating 14c and return the light to the laser chamber 10 through the window 10a.

[0098] The output coupling mirror included in the wavefront modifier 15 a transmits and outputs a portion of the light emitted from the window 10 b of the laser chamber 10 , and reflects the other portion and returns it to the inside of the laser chamber 10 through the window 10 b .

[0099] In this way, the light emitted from the laser chamber 10 reciprocates between the narrowband module 14 and the output coupling mirror, and is amplified each time it passes through the discharge space inside the laser chamber 10. The light is narrowbanded each time it is turned back by the narrowband module 14. The light that is laser oscillated and narrowbanded in this way is output from the output coupling mirror as a pulsed laser. The repetition frequency of the pulsed laser is the same as the repetition frequency of the high voltage pulse applied to the discharge electrode 11a, and the repetition frequency changes according to the repetition frequency of the trigger signal received from the exposure device 100.

[0100] 1.4.3 Monitoring module 16

[0101] The energy detector 16c detects the pulse energy of the pulse laser and outputs the pulse energy data to the laser control processor 30. The pulse energy data is used by the laser control processor 30 to perform feedback control on the setting data of the voltage applied to the discharge electrode 11a.

[0102] In the spectrum detector 16d, interference fringes formed by an etalon (not shown) are measured by a light distribution sensor (not shown), and an edge waveform representing the light intensity distribution of the interference fringes is generated.

[0103] 1.4.4 Sudden Oscillation

[0104] Figure 3 1 is a diagram showing an example of output timing of pulsed laser. The laser device 1 performs laser oscillation at a repetition frequency greater than a certain value during a certain period according to a trigger signal from the exposure control processor 110. Performing laser oscillation at a repetition frequency greater than a certain value and outputting pulsed laser light is called "burst oscillation".

[0105] When the trigger signal from the exposure control processor 110 stops, the laser device 1 stops burst oscillation. Thereafter, the laser device 1 performs burst oscillation again according to the trigger signal from the exposure control processor 110. The period between the first burst oscillation and the next second burst oscillation is called a "rest period".

[0106] The period of burst oscillation corresponds to, for example, the period of exposure of one exposure area of ​​a semiconductor wafer in exposure device 100. The rest period corresponds to, for example, the period of moving the imaging position of the mask pattern from one exposure area to another exposure area in exposure device 100 or the period of replacing a semiconductor wafer.

[0107] 1.4.5 Spectral line width control

[0108] Refer again Figure 2 The linear stage 15d included in the wavefront adjuster 15a moves the cylindrical concave lens 15c along the optical path between the laser chamber 10 and the cylindrical convex lens 15b according to the control signal output from the laser control processor 30. As a result, the wavefront of the light from the wavefront adjuster 15a toward the narrowband module 14 changes. The spectral line width of the pulsed laser changes due to the change in the wavefront.

[0109] Figure 4 1 is a flowchart showing the steps of line width control in the comparative example. Figure 4 Processing shown.

[0110] In S1 , the laser control processor 30 receives a target line width from the exposure device 100 .

[0111] In S2, the laser control processor 30 calculates the spectral line width based on the data of the edge waveform output from the spectrum detector 16d.

[0112] Specifically, the laser control processor 30 extracts a portion of the waveform corresponding to the free spectrum range of the etalon from the edge waveform. The portion of the waveform extracted from the edge waveform represents the relationship between the distance from the center of the concentric circles constituting the interference fringes and the light intensity. Next, the laser control processor 30 obtains the spectrum waveform by transforming the waveform coordinates into the relationship between the wavelength and the light intensity. The laser control processor 30 calculates the spectral line width based on the spectral waveform. The spectral line width can be the full width at half maximum or an indicator called E95.

[0113] Figure 5 An example of a spectrum waveform for explaining E95 is shown. Figure 5 The horizontal axis of the spectrum represents wavelength, and the vertical axis represents light intensity. The total width of the portion of the spectrum that accounts for 95% of the total energy centered at the central wavelength λ0 is defined as E95.

[0114] Refer again Figure 4 In S3, the laser control processor 30 calculates the difference ΔΔλ between the received target spectral line width and the calculated spectral line width.

[0115] In S4, the laser control processor 30 sends a control signal to the wavefront adjuster 15a based on the difference ΔΔλ, thereby performing feedback control on the line width of the pulse laser.

[0116] In S5, the laser control processor 30 determines whether to end the control of the spectral line width. For example, when the burst oscillation of the pulsed laser output at a certain repetition frequency ends and enters the rest period, the control of the spectral line width ends. When the control of the spectral line width ends (S5: Yes), the laser control processor 30 ends the processing of this flowchart. When the control of the spectral line width does not end (S5: No), the laser control processor 30 returns the processing to S1 to repeat the above-mentioned actions.

[0117] 1.5 Issues of Comparative Example

[0118] Figure 6The measurement results of the variation of the spectral line width corresponding to the repetition frequency of the pulsed laser in the comparative example are shown. The variation of the spectral line width is measured by the following steps. First, the repetition frequency of the pulsed laser is set to 6000 Hz to perform the first burst oscillation, and the spectral line width is controlled using the wavefront adjuster 15a. Thereafter, the control of the spectral line width using the wavefront adjuster 15a is terminated, and the repetition frequency of the pulsed laser is set to, for example, 4500 Hz, and a second burst oscillation next to the first burst oscillation is performed. The difference between the target spectral line width in the first burst oscillation and the average value of the spectral line width of a specified number of pulses from the initial pulse in the second burst oscillation is set as the variation of the spectral line width. Similarly, after the first burst oscillation is performed with the repetition frequency set to 6000 Hz, the variation of the spectral line width is measured by switching to other repetition frequencies.

[0119] exist Figure 6 , it is shown that the maximum line width variation is 50 fm due to the change in the repetition frequency of the pulsed laser. Hereinafter, the maximum value of the line width variation caused by the change in the repetition frequency is referred to as the variation amplitude.

[0120] Figure 7 The simulation results of the variation of the line width according to the repetition frequency of the pulsed laser in the comparative example are shown.

[0121] exist Figure 7 , it is shown that the variation of the spectral line width caused by the change in the repetition frequency of the pulsed laser is 59 fm.

[0122] When a pulsed laser is generated in the laser device 1, an acoustic wave is generated inside the laser chamber 10. The acoustic wave is a density wave of the gas. If the acoustic wave reaches the optical path of the laser resonator inside the laser chamber 10, a refractive index distribution is generated on the optical path due to the compression of the gas. According to the refractive index distribution of the optical path, the wavefront of the light toward the narrowband module 14 changes, and the spectral line width of the pulsed laser changes. The relationship between the timing of the acoustic wave reaching the optical path and the timing of the light passing through depends on the repetition frequency of the pulsed laser. Therefore, it is considered that when the repetition frequency of the pulsed laser changes, the spectral line width of the pulsed laser changes.

[0123] As reference Figure 4 As described above, the line width is feedback-controlled using the wavefront adjuster 15 a . However, the line width changes greatly at the timing of switching the repetition frequency of the pulsed laser light, and it may take time for the line width to converge to the target line width through feedback control.

[0124] The case where the repetition frequency of the pulsed laser light is changed is, for example, the following case.

[0125] (a) When the repetition frequency of the trigger signal received from the exposure control processor 110 changes

[0126] (b) When the repetition frequency is changed during the calibration of the laser device 1, and the repetition frequency is restored to the original repetition frequency after the calibration is completed.

[0127] (c) When the repetition frequency is changed during the calibration of the laser device 1, and the repetition frequency is restored to the original repetition frequency after the calibration is completed.

[0128] The embodiment described below relates to suppressing the variation of the spectral line width when the repetition frequency of pulsed laser light is changed.

[0129] 2. Laser device 1a including concave grating 14c

[0130] 2.1 Structure

[0131] Figure 8 The structure of the laser device 1a of the first embodiment is schematically shown. The narrowband module 14 included in the laser device 1a includes a grating 14c having a concave reflection surface. In order to adjust the shape of the reflection surface of the grating 14c, a grating bending mechanism including a bracket 14d, an extension portion 14e, and support portions 14f and 14g may also be provided.

[0132] Fig. 9 The structure of the narrowband module 14 in the first embodiment is shown. The bracket 14d included in the grating bending mechanism is located at a position opposite to the back surface of the grating 14c, and the supporting parts 14f and 14g support both ends of the grating 14c. The telescopic part 14e located between the supporting parts 14f and 14g is configured to include, for example, a bolt, and by adjusting the interval between the central part of the grating 14c and the bracket 14d, the curvature of the reflection surface 14h of the grating 14c can be adjusted. When the interval is narrowed, the reflection surface 14h becomes concave, and when the interval is widened, the reflection surface 14h becomes convex.

[0133] The grating 14c includes a plurality of grooves and ridges parallel to the V axis, and these grooves and ridges are arranged alternately in a direction perpendicular to the V axis. The curved surface including these ridges, that is, the surface of the grating 14c formed when all the grooves of the grating 14c are filled, is used as the reflection surface 14h of the grating 14c. The reflection surface 14h can also be a part of a cylinder curved in a plane perpendicular to the V axis, and the radius of the cylinder is set as the curvature radius R_Grating. The curvature radius R_Grating of the reflection surface 14h can be calculated based on the measurement result obtained by measuring the wavefront of the light diffracted by the grating 14c and heading toward the prism 14b by a wavefront measuring instrument not shown in the figure. As a wavefront measuring instrument, GPI-XP of Zygo Corporation of the United States can be used.

[0134] If the beam width of the light incident from the laser chamber 10 to the prism 14a in the direction perpendicular to the V axis is set to w1, and the beam width of the light incident from the prism 14b to the grating 14c in the direction perpendicular to the V axis is set to w2, the beam magnification M of the prisms 14a and 14b is given by the following formula.

[0135] M=w2 / w1

[0136] 2.2 Grating 14c g parameter g_Grating

[0137] The incident angle of light incident from the prism 14b to the grating 14c is θ. The optical path length between the principal points of the grating 14c and the wavefront modifier 15a is L (refer to Figure 8 ). At this time, the g parameter g_Grating of the grating 14c is defined by the following formula.

[0138] g_Grating=1-(L×M 2 ) / (R_Grating×cosθ)

[0139] When the reflecting surface 14h is a concave surface, the g parameter g_Grating is a value less than 1. For example, when the optical path length L between the principal points of the grating 14c and the wavefront modifier 15a is 1×10 3 mm, the beam magnification M of the prisms 14a and 14b is 40 times, and the curvature radius R_Grating of the reflecting surface 14h is 1×10 7 When the incident angle θ of the light incident from the prism 14 b to the grating 14 c is 70 degrees, the g parameter g_Grating is approximately 0.53.

[0140] When the reflecting surface 14h is convex, the g parameter g_Grating is a value greater than 1.

[0141] 2.3 g parameter g_EFM of the wavefront regulator 15a

[0142] Fig.10 The structure of the wavefront adjuster 15a in the first embodiment is shown. The focal axis of the cylindrical concave lens 15c is set to F1, the focal length is set to f1, the focal axis of the cylindrical convex lens 15b is set to F2, the focal length is set to f2, and the distance between the principal points of the cylindrical concave lens 15c and the cylindrical convex lens 15b is set to d. The g parameter g_EFM of the wavefront adjuster 15a is calculated as follows.

[0143] First, the composite focal length f_EFM of the wavefront modifier 15a in the optical path of the laser chamber 10 entering the wavefront modifier 15a and reflected by the partial reflection film 15e of the cylindrical convex lens 15b and returning to the laser chamber 10 is calculated. The composite focal length f_EFM1 from the laser chamber 10 to the partial reflection film 15e is as follows.

[0144] f_EFM1=(f1×f2) / (f1+f2-d)

[0145] The synthetic focal length f_EFM2 from the partial reflection film 15 e to the laser chamber 10 is the same as the synthetic focal length f_EFM1 .

[0146] f_EFM2=f_EFM1

[0147] The synthetic focal length f_EFM of the wavefront adjuster 15a is as follows.

[0148] f_EFM=(f_EFM1×f_EFM1) / (f_EFM1+f_EFM1+δ1-δ2)

[0149] Here, δ1 is the distance between the cylindrical concave lens 15c and the image-side principal point, and is calculated by the following formula.

[0150] δ1=f_EFM1×d / f2

[0151] δ2 is the distance between the cylindrical convex lens 15b and the object-side principal point, and is calculated by the following formula.

[0152] δ2=f_EFM1×d / f1

[0153] The g parameter g_EFM of the wavefront adjuster 15a is calculated as follows.

[0154] g_EFM=1-L / (2×f_EFM)

[0155] When the focal length f2 of the cylindrical convex lens 15b is smaller than the sum of the absolute value of the focal length f1 of the cylindrical concave lens 15c and the distance d between the principal points of the cylindrical concave lens 15c and the cylindrical convex lens 15b, the g parameter g_EFM is smaller than 1. For example, when the optical path length L between the principal points between the grating 14c and the wavefront modifier 15a is set to 1×10 3 mm, focal length f1 is set to -70mm, focal length f2 is set to 74mm, and distance d is set to 6mm, the g parameter g_EFM is approximately 0.58.

[0156] When the focal length f2 is greater than the sum of the absolute value of the focal length f1 and the distance d, the g parameter g_EFM is a value greater than 1.

[0157] 2.4g parameter and the relationship between the spectral line width

[0158] Fig.11 : is a graph showing the simulation results of the spectral line width of the pulsed laser light corresponding to the g-parameters g_Grating and g_EFM of the grating 14 c and the wavefront modifier 15 a . Fig.11The horizontal axis represents the g parameter g_Grating of the grating 14c, and the vertical axis represents the g parameter g_EFM of the wavefront modifier 15a. The contour lines of the spectral line width for each combination of these g parameters are shown in the graph. The contour lines are alternately drawn with solid lines and dashed lines every 0.0375 pm.

[0159] In the comparative example, the reflection surface of the grating 14 c is planar, and therefore the g parameter g_Grating of the grating 14 c is 1. When the g parameter g_Grating is fixed to 1 and the g parameter g_EFM of the wavefront modifier 15 a is changed, the line width of the pulsed laser light changes.

[0160] In the first embodiment, the reflection surface of the grating 14c is set to a concave shape, and the g parameter g_Grating of the grating 14c is less than 1. If the g parameter g_Grating is less than 1, the interval of the contour lines of the spectral line width becomes wider. That is, the stability of the spectral line width when the g parameter g_EFM of the wavefront modifier 15a is changed becomes higher. It is considered that when the refractive index distribution is generated on the optical path of the laser resonator due to the acoustic wave, the stability of the spectral line width is also increased.

[0161] exist Fig.11 The line width of the pulsed laser can take a value of 0.15 pm to 0.75 pm, but the line width is preferably greater than or equal to 0.15 pm and less than or equal to 0.5 pm.

[0162] Fig.12 The measurement results of the variation of the spectral line width corresponding to the repetition frequency of the pulsed laser light in the first embodiment are shown. The g parameter g_Grating of the grating 14 c is set to 0.4.

[0163] exist Fig.12 , it is shown that the variation of the spectral line width caused by the change in the repetition frequency of the pulsed laser is 37 fm.

[0164] Fig.13 The simulation results of the variation of the spectral line width according to the repetition frequency of the pulsed laser light in the first embodiment are shown. The g parameter g_Grating of the grating 14 c is set to 0.4.

[0165] exist Fig.13 , it is shown that the variation of the spectral line width caused by the change in the repetition frequency of the pulsed laser is 34 fm.

[0166] According to the first embodiment, it is possible to suppress the variation of the spectral line width when the repetition frequency of the pulsed laser light is changed, thereby improving the stability of the spectral line width.

[0167] Relationship between 2.5g parameters and pulse energy

[0168] Fig.14: is a graph showing the result of simulating the relationship between the g parameter g_Grating of the grating 14c and the pulse energy. The target line width when simulating the pulse energy is 0.3 pm. Fig.14 The variation range of the spectral line width caused by the change of the repetition frequency of the pulsed laser is also shown. Fig.14 The horizontal axis represents the g parameter g_Grating of the grating 14 c , and the vertical axis represents the relative value of the pulse energy or the variation range of the spectral line width based on the pulse energy when g_Grating is set to 1.

[0169] The smaller the g parameter g_Grating is, the smaller the fluctuation range of the spectral line width is. Therefore, it is preferable that the g parameter g_Grating is small.

[0170] However, when the g parameter g_Grating is greater than or equal to 0.4 and less than 0.5, the pulse energy reaches a peak value, and the pulse energy becomes lower regardless of whether the g parameter g_Grating is greater or less than this range. The pulse energy when the g parameter g_Grating is 0.2 is approximately the same as the pulse energy when the g parameter g_Grating is 1. It is believed that when the g parameter g_Grating is less than 0.2 or greater than 1.0, the proportion of light incident on the wavefront adjuster 15a in the light diffracted by the grating 14c decreases, leaks to the outside of the laser resonator, and the pulse energy decreases. Therefore, the g parameter g_Grating is preferably greater than or equal to 0.2 and less than 1.0, and more preferably greater than or equal to 0.4 and less than 0.5.

[0171] 2.6 Function

[0172] (1) According to the first embodiment, the laser device 1 a includes a laser resonator, a laser chamber 10 , a power supply 12 , a wavefront modifier 15 a , a spectrum detector 16 d , and a laser control processor 30 .

[0173] The laser resonator includes an output coupling mirror formed by the flat surface of a cylindrical convex lens 15b and a narrowband module 14. The narrowband module 14 includes prisms 14a and 14b and a grating 14c. The reflection surface 14h of the grating 14c is concave.

[0174] The laser chamber 10 includes a discharge electrode 11 a and a discharge electrode paired therewith, and is disposed on an optical path of a laser resonator.

[0175] The power source 12 is configured to apply a high voltage pulse to the discharge electrode 11 a , and the repetition frequency of the high voltage pulse is variable.

[0176] The wavefront modifier 15a includes an output coupling mirror.

[0177] The spectrum detector 16d generates a fringe waveform in order to measure the spectral line width of the pulse laser light output from the output coupling mirror and reflected by the beam splitter 16a.

[0178] The laser control processor 30 controls the wavefront adjuster 15a based on the measured spectral line width.

[0179] Thus, by making the reflecting surface 14h concave, it is possible to suppress the variation of the spectral line width due to the change of the repetition frequency of the pulsed laser light, and stabilize the spectral line width.

[0180] (2) According to the first embodiment, when the curvature radius of the reflection surface 14h of the grating 14c is set to R_Grating, the incident angle of the light incident on the grating 14c from the prisms 14a and 14b is set to θ, the optical path length from the principal point of the grating 14c to the principal point of the wavefront modifier 15a is set to L, and the beam magnification of the prisms 14a and 14b is set to M, the formula

[0181] g_Grating=1-(L×M 2 ) / (R_Grating×cosθ)

[0182] The calculated value of g_Grating is greater than or equal to 0.2 and less than 1.0.

[0183] This can stabilize the line width and suppress a decrease in pulse energy.

[0184] (3) According to the first embodiment, the value of g_Grating is greater than or equal to 0.4 and less than 0.5.

[0185] This makes it possible to stabilize the line width and obtain high pulse energy.

[0186] (4) According to the first embodiment, when the synthetic focal length of the wavefront adjuster 15a is set to f_EFM, the laser control processor 30 controls the wavefront adjuster 15a so that

[0187] g_EFM=1-L / (2×f_EFM)

[0188] The calculated g_EFM becomes a value larger than the value of g_Grating.

[0189] Thus, by increasing the g parameter g_EFM of the wavefront modifier 15 a by the amount by which the g parameter g_Grating of the grating 14 c is reduced, it is possible to achieve a target spectral line width.

[0190] (5) According to the first embodiment, the laser control processor 30 is configured to control the wavefront adjuster 15a so that the spectral line width measured by the spectrum detector 16d is greater than 0.15 pm and less than 0.5 pm, and the g parameter g_Grating of the grating 14c is greater than 0.2 and less than 1.0.

[0191] Thus, by setting the line width to be greater than or equal to 0.15 pm and less than or equal to 0.5 pm and setting the g parameter g_Grating of the grating 14 c to be greater than or equal to 0.2 and less than 1.0, the line width is stabilized and a decrease in pulse energy can be suppressed.

[0192] (6) According to the first embodiment, the grating 14c includes a plurality of grooves in the direction of the V axis, and the reflection surface 14h is a concave surface curved in a plane perpendicular to the direction of the V axis.

[0193] Thus, by adjusting the wavefront shape in a plane perpendicular to the direction of the V-axis, the spectral line width can be stabilized.

[0194] (7) According to the first embodiment, the surface of prism 14a on which light traveling back and forth in the laser resonator is incident and the surface from which light is emitted from prism 14a and the surface of prism 14b on which light is incident and the surface from which light is emitted from prism 14b are parallel to the direction of the V axis.

[0195] Thus, by expanding the beam width in a plane perpendicular to the V-axis direction by the prisms 14 a and 14 b and making the beam incident on the grating 14 c , the line width can be narrowed.

[0196] (8) According to the first embodiment, the wavefront adjuster 15a includes the cylindrical convex lens 15b having the focal axis F2 parallel to the direction of the V axis and the cylindrical concave lens 15c having the focal axis F1 parallel to the direction of the V axis.

[0197] Thus, by adjusting the wavefront shape in a plane perpendicular to the direction of the V-axis, the spectral line width can be controlled.

[0198] (9) According to the first embodiment, the wavefront adjuster 15a includes a cylindrical convex lens 15b, a cylindrical concave lens 15c, and a linear stage 15d. The cylindrical convex lens 15b includes a flat surface constituting an output coupling mirror and a convex surface located between the flat surface and the laser chamber 10. The cylindrical concave lens 15c is located on the optical path between the cylindrical convex lens 15b and the laser chamber 10. The linear stage 15d moves the cylindrical concave lens 15c.

[0199] Thus, by moving the cylindrical concave lens 15 c , the wavefront can be adjusted to control the spectral line width without changing the resonator length.

[0200] (10) According to the first embodiment, the narrowband module 14 includes a grating bending mechanism including the bracket 14d for adjusting the curvature of the grating 14c, the telescopic portion 14e, and the supporting portions 14f and 14g.

[0201] Thereby, the curvature of the reflection surface 14h of the grating 14c can be adjusted to an appropriate value.

[0202] Regarding other aspects, the first embodiment is the same as the comparative example.

[0203] 3. Master oscillator MO and laser device 1b including power oscillator PO

[0204] 3.1 Structure

[0205] Fig.15 The structure of the laser device 1b in the second embodiment is schematically shown. The laser device 1b includes a master oscillator MO, a power oscillator PO, a monitoring module 16, a laser control processor 30, and high reflection mirrors 31 and 32. The structure of the laser control processor 30 is the same as the corresponding structure in the first embodiment.

[0206] The master oscillator MO includes a laser cavity 10, a discharge electrode 11a, a narrowband module 14, and a wavefront adjuster 15a. These structures are the same as the corresponding structures in the first embodiment, and the reflection surface of the grating 14c included in the narrowband module 14 is concave. Fig.15 FIG. 1 shows the discharge electrode 11b which is paired with the discharge electrode 11a. Fig.15 The power supply 12 is omitted in the figure.

[0207] High reflective mirrors 31 and 32 are arranged on the optical path of the pulse laser B1 output from the master oscillator MO. The high reflective mirrors 31 and 32 are respectively configured to be able to change the position and posture by an actuator not shown. The high reflective mirrors 31 and 32 constitute a beam steering unit for adjusting the incident position and incident direction of the pulse laser B1 to the power oscillator PO.

[0208] The power oscillator PO is disposed on the optical path of the pulse laser B1 that has passed through the beam steering unit. The power oscillator PO includes a laser chamber 20 , a discharge electrode 21 a and a discharge electrode 21 b paired therewith, a rear mirror 24 , and an output coupling mirror 25 .

[0209] The rear mirror 24 is made of a material that allows the pulse laser B1 to pass through, and a partial reflection film is coated on one surface thereof. The same is true for the output coupling mirror 25. However, the reflectivity of the rear mirror 24 is set higher than the reflectivity of the output coupling mirror 25. The rear mirror 24 and the output coupling mirror 25 constitute a laser resonator. The laser cavity 20 is arranged on the optical path of the laser resonator. Windows 20a and 20b are provided at both ends of the laser cavity 20.

[0210] Regarding other aspects, the above-mentioned components of the power oscillator PO are the same as the corresponding components of the main oscillator MO.

[0211] The monitoring module 16 is disposed on the optical path of the pulse laser B2 output from the output coupling mirror 25. The structure of the monitoring module 16 is the same as the corresponding structure in the first embodiment. Fig.15 The energy detector 16c and the beam splitter 16b are omitted in the figure.

[0212] 3.2 Action

[0213] 3.2.1 Laser control processor 30

[0214] The laser control processor 30 receives setting data of a first target pulse energy of the pulse laser B2 output from the power oscillator PO from the exposure control processor 110 .

[0215] The laser control processor 30 also sets a second target pulse energy of the pulse laser B1 output from the master oscillator MO.

[0216] The laser control processor 30 sends setting data of applied voltage to the power supplies of the master oscillator MO and the power oscillator PO, respectively, according to the first and second target pulse energies.

[0217] The laser control processor 30 sends the first and second oscillation trigger signals based on the trigger signal received from the exposure control processor 110 to switches included in the power supplies of the main oscillator MO and the power oscillator PO.

[0218] 3.2.2 Main Oscillator MO

[0219] The operation of the master oscillator MO is the same as that of the laser device 1 a in the first embodiment.

[0220] 3.2.3 Power Oscillator PO

[0221] The power source included in the power oscillator PO generates a high voltage pulse upon receiving the second oscillation trigger signal from the laser control processor 30, and applies the high voltage pulse to the discharge electrode 21a.

[0222] The delay time of the second oscillation trigger signal sent to the power supply contained in the power oscillator PO relative to the first oscillation trigger signal sent to the power supply contained in the master oscillator MO is set so that the timing of the discharge inside the laser chamber 20 is synchronized with the timing of the pulse laser B1 output from the master oscillator MO being incident on the inside of the laser chamber 20.

[0223] The pulse laser light B1 reciprocates between the rear 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 pulse laser light B2 is output from the output coupling mirror 25 .

[0224] 3.3 Function

[0225] According to the second embodiment, by amplifying the pulse laser light B1 output from the master oscillator MO, it is possible to output the pulse laser light B2 having high pulse energy toward the exposure device 100 .

[0226] The spectral line width of the pulse laser light B2 depends on the spectral line width of the pulse laser light B1. By making the reflection surface of the grating 14c concave, the spectral line width of the pulse laser light B2 can be stabilized.

[0227] Regarding other aspects, the second embodiment is the same as the first embodiment.

[0228] 4. Laser device 1c including a ring resonator

[0229] 4.1 Structure

[0230] Fig.16 The structure of a laser device 1 c according to the third embodiment is schematically shown. Fig.17 Shown from Fig.16 Observe from different directions Fig.16 The laser device 1c includes a master oscillator MO, a power oscillator PO, a monitoring module 16, a laser control processor 30, and high reflective mirrors 31 and 32. The structure of the master oscillator MO is the same as the corresponding structure in the second embodiment, and the reflecting surface of the grating 14c included in the narrowband module 14 is concave.

[0231] The power oscillator PO includes a laser chamber 20, high reflection mirrors 26a to 26c, an output coupling mirror 27, and a high reflection mirror 33. The structures of the laser chamber 20, windows 20a and 20b provided in the laser chamber 20, and a pair of discharge electrodes 21a and 21b are the same as the corresponding structures in the second embodiment.

[0232] The output coupling mirror 27 and the high reflection mirror 26a are arranged outside the laser chamber 20 and near the window 20a. The high reflection mirrors 26b and 26c are arranged outside the laser chamber 20 and near the window 20b. In the discharge space inside the laser chamber 20, the optical path from the high reflection mirror 26a to the high reflection mirror 26b intersects with the optical path from the high reflection mirror 26c to the output coupling mirror 27. The laser resonator composed of the high reflection mirrors 26a to 26c and the output coupling mirror 27 is called a ring resonator.

[0233] 4.2 Action

[0234] The pulse laser B1 output from the master oscillator MO is sequentially reflected by the high reflection mirrors 31, 32, and 33, and is incident on the output coupling mirror 27 from the outer side of the laser resonator of the power oscillator PO in the substantially -H direction. The pulse laser B1 incident on the laser resonator via the output coupling mirror 27 is sequentially reflected by the high reflection mirrors 26a, 26b, and 26c, is amplified when passing through the discharge space, and is incident on the output coupling mirror 27 from the inner side of the laser resonator in the Z direction.

[0235] A portion of the pulsed laser B1 incident on the output coupling mirror 27 in the Z direction is reflected toward the substantially -H direction, and is reflected again by the high reflection mirrors 26a, 26b, and 26c and amplified. Another portion of the pulsed laser B1 incident on the output coupling mirror 27 in the Z direction passes through the output coupling mirror 27 and is output toward the exposure device 100 as the pulsed laser B2.

[0236] 4.3 Function

[0237] According to the third embodiment, since return light from the power oscillator PO to the master oscillator MO is less likely to be generated, the master oscillator MO can be operated stably.

[0238] Regarding other aspects, the third embodiment is the same as the second embodiment.

[0239] 5. Others

[0240] 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 can be used in combination.

[0241] 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 existence of constituent elements other than the recorded constituent elements". 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". Furthermore, it should be interpreted as also including their combination with constituent elements other than "A", "B" and "C".

Claims

1. A narrow-band laser device, wherein: The narrowband laser device comprises: A laser resonator, comprising an output coupling mirror and a narrowband module, wherein the narrowband module comprises a prism and a grating, wherein the reflection surface of the grating is concave; a laser chamber comprising a pair of discharge electrodes and arranged on an optical path of the laser resonator; A power supply, which applies high voltage pulses to the discharge electrode, wherein the repetition frequency of the high voltage pulses is variable; A wavefront modifier, comprising the output coupling mirror; A spectrum detector, which is used to measure the spectral line width of the pulsed laser output from the output coupling mirror; as well as A processor controls the wavefront modifier based on the measured spectral line width.

2. The narrowband laser device according to claim 1, wherein: When the curvature radius of the reflection surface of the grating is set to R_Grating, the incident angle of the light incident from the prism to the grating is set to θ, the optical path length from the principal point of the grating to the principal point of the wavefront adjuster is set to L, and the beam magnification of the prism is set to M, the formula g_Grating=1-(L×M 2 ) / (R_Grating×cosθ) The calculated value of g_Grating is greater than or equal to 0.2 and less than 1.

0.

3. The narrowband laser device according to claim 2, wherein: The value of g_Grating is greater than or equal to 0.4 and less than 0.

5.

4. The narrowband laser device according to claim 2, wherein: When the synthetic focal length of the wavefront adjuster is set to f_EFM, the processor controls the wavefront adjuster so that g_EFM=1-L / (2×f_EFM) The calculated g_EFM becomes a value larger than the value of the above-mentioned g_Grating.

5. The narrowband laser device according to claim 2, wherein: The processor controls the wavefront adjuster so that the measured spectral line width is greater than or equal to 0.15 pm and less than or equal to 0.5 pm.

6. The narrowband laser device according to claim 1, wherein: The grating includes a plurality of grooves in a first direction, and the reflection surface is a concave surface curved in a plane perpendicular to the first direction.

7. The narrowband laser device according to claim 6, wherein: A surface of the prism on which the light reciprocating in the laser resonator is incident on the prism and a surface on which the light is emitted from the prism are parallel to the first direction.

8. The narrowband laser device according to claim 6, wherein: The wavefront modifier includes a cylindrical convex lens and a cylindrical concave lens, each having a focal axis parallel to the first direction.

9. The narrowband laser device according to claim 1, wherein: The wave surface regulator comprises: a cylindrical plano-convex lens comprising a flat surface constituting the output coupling mirror and a convex surface located between the flat surface and the laser chamber; a cylindrical concave lens located on an optical path between the cylindrical plano-convex lens and the laser chamber; and An actuator moves the cylindrical concave lens.

10. The narrowband laser device according to claim 1, wherein: The narrowbanding module includes a grating bending mechanism for adjusting the curvature of the grating.

11. A method for manufacturing an electronic device, wherein: The manufacturing method of the electronic device comprises the following steps: Generate pulsed laser using narrowband laser device; outputting the pulse laser to an exposure device; and exposing the pulsed laser on a photosensitive substrate in the exposure device to manufacture the electronic device, The narrowband laser device comprises: A laser resonator, comprising an output coupling mirror and a narrowband module, wherein the narrowband module comprises a prism and a grating, wherein the reflection surface of the grating is concave; a laser chamber comprising a pair of discharge electrodes and arranged on an optical path of the laser resonator; A power supply, which applies high voltage pulses to the discharge electrode, wherein the repetition frequency of the high voltage pulses is variable; A wavefront modifier, comprising the output coupling mirror; a spectrum detector for measuring the spectral line width of the pulsed laser output from the output coupling mirror; as well as A processor controls the wavefront modifier based on the measured spectral line width.

12. The method for manufacturing an electronic device according to claim 11, wherein: When the curvature radius of the reflection surface of the grating is set to R_Grating, the incident angle of the light incident from the prism to the grating is set to θ, the optical path length from the principal point of the grating to the principal point of the wavefront adjuster is set to L, and the beam magnification of the prism is set to M, the formula g_Grating=1-(L×M 2 ) / (R_Grating×cosθ) The calculated value of g_Grating is greater than or equal to 0.2 and less than 1.

0.

13. The method for manufacturing an electronic device according to claim 12, wherein: The value of g_Grating is greater than or equal to 0.4 and less than 0.

5.

14. The method for manufacturing an electronic device according to claim 12, wherein: When the synthetic focal length of the wavefront adjuster is set to f_EFM, the processor controls the wavefront adjuster so that g_EFM=1-L / (2×f_EFM) The calculated g_EFM becomes a value larger than the value of g_Grating described above.

15. The method for manufacturing an electronic device according to claim 12, wherein: The processor controls the wavefront adjuster so that the measured spectral line width is greater than or equal to 0.15 pm and less than or equal to 0.5 pm.

16. The method for manufacturing an electronic device according to claim 11, wherein: The grating includes a plurality of grooves in a first direction, and the reflection surface is a concave surface curved in a plane perpendicular to the first direction.

17. The method for manufacturing an electronic device according to claim 16, wherein: A surface of the prism on which the light reciprocating in the laser resonator is incident on the prism and a surface on which the light is emitted from the prism are parallel to the first direction.

18. The method for manufacturing an electronic device according to claim 16, wherein: The wavefront modifier includes a cylindrical convex lens and a cylindrical concave lens, each having a focal axis parallel to the first direction.

19. The method for manufacturing an electronic device according to claim 11, wherein: The wave surface regulator comprises: a cylindrical plano-convex lens comprising a flat surface constituting the output coupling mirror and a convex surface located between the flat surface and the laser chamber; a cylindrical concave lens located on an optical path between the cylindrical plano-convex lens and the laser chamber; and An actuator moves the cylindrical concave lens.

20. The method for manufacturing an electronic device according to claim 11, wherein: The narrowbanding module includes a grating bending mechanism for adjusting the curvature of the grating.

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