Laser device, wavelength control method, and method for manufacturing electronic device

Abstract

The laser device (100) comprises: a first optical element (51) and a second optical element (52); a first actuator (512) which changes the posture of the first optical element (51), thereby changing the first wavelength component contained in the pulsed laser; a second actuator (522) which changes the posture of the second optical element (52), thereby changing the second wavelength component contained in the pulsed laser; a first encoder (513) which measures the position of the first actuator (512); a second encoder (523) which measures the position of the second actuator (522); and a processor (130). The processor (130) reads in a first relationship between the position of the first actuator (512) and the first wavelength component and a second relationship between the position of the second actuator (522) and the second wavelength component, controls the first actuator (512) based on the first relationship and the position of the first actuator (512) measured by the first encoder (513), and controls the second actuator (522) based on the second relationship and the position of the second actuator (522) measured by the second encoder.

Description

Technical Field

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

[0002] In recent years, in semiconductor exposure devices, as semiconductor integrated circuits become smaller and more highly integrated, there is a demand for improved resolution. Hereinafter, semiconductor exposure devices are referred to as "exposure devices". Therefore, the wavelength of light output from the exposure light source has been shortened. For example, as gas laser devices for exposure, KrF excimer laser devices that output laser light with a wavelength of about 248nm and ArF excimer laser devices that output laser light with a wavelength of about 193nm are used.

[0003] The spectral line width of the natural oscillation light of the KrF excimer laser device and the ArF excimer laser device is relatively wide, at 350pm to 400pm. Therefore, chromatic aberration is sometimes generated due to the projection lens of the exposure device. 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 Narrow Module) including a narrowing element is sometimes provided in the laser resonator of the gas laser device. The narrowing element includes, for example, an etalon or a grating. A gas laser device whose spectral line width is narrowed in this way is called a narrowed gas laser device.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: U.S. Patent Application Publication No. 2011 / 0116522

[0007] Patent Document 2: Japanese Patent Application Publication No. 2006-269628 Summary of the invention

[0008] A laser device according to one aspect of the present disclosure includes: a first optical element and a second optical element; a first actuator that changes the posture of the first optical element to change the first wavelength component included in the pulsed laser light; a second actuator that changes the posture of the second optical element to change the second wavelength component included in the pulsed laser light; a first encoder that measures the position of the first actuator; a second encoder that measures the position of the second actuator; and a processor. The processor reads a first relationship between the position of the first actuator and the first wavelength component and a second relationship between the position of the second actuator and the second wavelength component, and the processor controls the first actuator according to the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator according to the second relationship and the position of the second actuator measured by the second encoder.

[0009] A wavelength control method according to one aspect of the present disclosure is a wavelength control method for a laser device, the laser device comprising: a first optical element and a second optical element; a first actuator that changes the posture of the first optical element to change the first wavelength component contained in the pulsed laser light; a second actuator that changes the posture of the second optical element to change the second wavelength component contained in the pulsed laser light; a first encoder that measures the position of the first actuator; a second encoder that measures the position of the second actuator; and a processor. The processor reads a first relationship between the position of the first actuator and the first wavelength component and a second relationship between the position of the second actuator and the second wavelength component, and the processor controls the first actuator according to the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator according to the second relationship and the position of the second actuator measured by the second encoder.

[0010] A method for manufacturing an electronic device according to one aspect of the present disclosure includes the following steps: generating a pulsed laser by a 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 laser device has: a first optical element and a second optical element; a first actuator that changes the posture of the first optical element, thereby changing a first wavelength component included in the pulsed laser; a second actuator that changes the posture of the second optical element, thereby changing a second wavelength component included in the pulsed laser; a first encoder that measures the position of the first actuator; a second encoder that measures the position of the second actuator; and a processor that reads a first relationship between the position of the first actuator and the first wavelength component and a second relationship between the position of the second actuator and the second wavelength component, and controls the first actuator according to the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator according to the second relationship and the position of the second actuator measured by the second encoder. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0012] Figure 1 The structure of an exposure system in a comparative example is schematically shown.

[0013] Figure 2 The structure of an exposure system in a comparative example is schematically shown.

[0014] Figure 3 The structure of a bandwidth narrowing device in a comparative example is schematically shown.

[0015] Figure 4 The structure of a bandwidth narrowing device in a comparative example is schematically shown.

[0016] Figure 5 The structure of the optical measuring device in the comparative example is schematically shown.

[0017] Figure 6 This is a graph showing an example of the measurement results of interference fringes by the spectroscopic sensor included in the optical measuring instrument.

[0018] Figure 7 This is a graph showing an example of the measurement results of interference fringes when a pulse laser beam having a wavelength λ1 and a pulse laser beam having a wavelength λ2 are respectively incident on a spectroscopic sensor.

[0019] Figure 8 This is a graph showing an example of the measurement results of interference fringes when a pulse laser beam having a wavelength λ1 and a pulse laser beam having a wavelength λ2 are simultaneously incident on a spectroscopic sensor.

[0020] Fig. 9 The configuration of the bandwidth narrowing device in the first embodiment is schematically shown.

[0021] Fig.10 The configuration of the bandwidth narrowing device in the first embodiment is schematically shown.

[0022] Fig.11 In the first embodiment, the arrangement of the parallel plane substrate is shown when the entire light beam is incident on the grating as the first portion.

[0023] Fig.12 The arrangement of the parallel plane substrate in the case where the entire light beam is incident on the grating as the second portion in the first embodiment is shown.

[0024] Fig.13 A configuration example of the first rotating table and the encoder in the first embodiment is shown.

[0025] Fig.14This is a graph showing an example of a spectrum waveform of pulsed laser light output from the laser device in the first embodiment.

[0026] Fig.15 This is a flowchart showing the operation of the laser control processor in the first embodiment.

[0027] Fig.16 This is a flowchart showing the process of wavelength λ1 calibration in the first embodiment.

[0028] Fig.17 1 is a flowchart showing the process of wavelength λ2 calibration in the first embodiment.

[0029] Fig.18 This is a flowchart showing the process of intensity ratio R calibration in the first embodiment.

[0030] Fig.19 This is a graph showing an example of the measurement results of interference fringes when pulsed laser beams of wavelength λ1 and wavelength λ2 having a wavelength difference of half the free spectral range are respectively incident on the spectroscopic sensor.

[0031] Fig. 20 It is a graph showing an example of the measurement results of interference fringes when pulsed lasers of wavelength λ1 and wavelength λ2 with a wavelength difference of half the free spectrum range are simultaneously incident on a spectroscopic sensor, and it is an example of the measurement results of interference fringes when the intensity ratio defined by Eλ1 / (Eλ1+Eλ2) is 1 / 2.

[0032] Fig.21 It is a graph showing an example of the measurement results of interference fringes when pulsed lasers of wavelength λ1 and wavelength λ2 with a wavelength difference of half the free spectral range are simultaneously incident on a spectroscopic sensor, and it is an example of the measurement results of interference fringes when the intensity ratio defined by Eλ1 / (Eλ1+Eλ2) is 10 / 11.

[0033] Fig. 22 An example of the first relationship obtained by calibration with wavelength λ1 is shown.

[0034] Fig.23 An example of the second relationship obtained by calibration with wavelength λ2 is shown.

[0035] Fig.24 An example of the third relationship obtained by the intensity ratio R calibration is shown.

[0036] Fig.25 This is a flowchart showing the process of outputting exposure light in the first embodiment.

[0037] Fig.26This is a flowchart showing the operation of the laser control processor in the second embodiment.

[0038] Fig. 27 : is a flowchart showing the process of calibrating the third relationship RY(f, V) in the second embodiment.

[0039] Fig.28 An example of data stored in the memory after calibration using the third relationship RY(f, V) is shown.

[0040] Fig.29 This is a flowchart showing the process of outputting exposure light in the second embodiment.

[0041] Fig.30 This is a flowchart showing the operation of the laser control processor in the third embodiment.

[0042] Fig.31 This is a flowchart showing the process of setting the position Y of the linear stage in the third embodiment.

[0043] Fig.32 This is a flowchart showing the process of outputting exposure light in the third embodiment.

[0044] Fig.33 The structure of the narrowband device in the fourth embodiment is schematically shown.

[0045] Fig.34 The structure of the narrowband device in the fourth embodiment is schematically shown.

[0046] Fig.35 The structure of a bandwidth narrowing device in a first modified example of the fourth embodiment is schematically shown.

[0047] Fig.36 The structure of a bandwidth narrowing device in a first modified example of the fourth embodiment is schematically shown.

[0048] Fig.37 The structure of a bandwidth narrowing device in a second modified example of the fourth embodiment is schematically shown.

[0049] Fig.38 The structure of a bandwidth narrowing device in a second modified example of the fourth embodiment is schematically shown. DETAILED DESCRIPTION

[0050] <Content>

[0051] 1. Comparative Example

[0052] 1.1 Exposure system

[0053] 1.2 Exposure device 200

[0054] 1.2.1 Structure

[0055] 1.2.2 Action

[0056] 1.3 Laser device 100

[0057] 1.3.1 Structure

[0058] 1.3.2 Action

[0059] 1.4 Narrowband Devices 14

[0060] 1.4.1 Structure

[0061] 1.4.1.1 Prisms 41 and 42

[0062] 1.4.1.2 Grating system 50

[0063] 1.4.2 Action

[0064] 1.5 Light measuring device 17

[0065] 1.5.1 Structure

[0066] 1.5.2 Action

[0067] 1.6 Issues of Comparative Example

[0068] 2. Laser device that adjusts wavelength by controlling a rotating stage based on encoder output

[0069] 2.1 Structure

[0070] 2.2 Action

[0071] 2.3 Encoder Example

[0072] 2.4 Example of intensity ratio R

[0073] 2.5 Operation of the Laser Control Processor 130

[0074] 2.5.1 Main Process

[0075] 2.5.2 Wavelength λ1 Calibration

[0076] 2.5.3 Wavelength λ2 Calibration

[0077] 2.5.4 Intensity ratio R calibration

[0078] 2.5.5 Exposure Light Output

[0079] 2.6 Function

[0080] 3. Laser device with the third relationship RY selected based on repetition frequency f and charging voltage V

[0081] 3.1 Main Process

[0082] 3.2 Calibration of the third relation RY(f,V)

[0083] 3.3 Exposure Light Output

[0084] 3.4 Function

[0085] 3.5 Other structural examples

[0086] 4. Laser device that adjusts the intensity ratio R without using the third relationship RY

[0087] 4.1 Main Process

[0088] 4.2 Setting the position Y of the linear stage 612

[0089] 4.3 Exposure Light Output

[0090] 4.4 Function

[0091] 5. Arrange a plurality of prisms 43 and 44 in the XZ plane to form a narrow band device 14d

[0092] 5.1 Structure

[0093] 5.2 Action

[0094] 5.3 First Modification

[0095] 5.4 Second Modification

[0096] 6. Others

[0097] Below, the embodiments of the present disclosure are described in detail with reference to the accompanying drawings. The embodiments described below show several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and actions described in each embodiment are not necessarily all necessary for the structures and actions of the present disclosure. In addition, the same reference numerals are marked on the same structural elements and repeated descriptions are omitted.

[0098] 1. Comparative Example

[0099] 1.1 Exposure system

[0100] Figure 1 and Figure 2 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 as only known to the applicant, and is not a publicly known example acknowledged by the applicant himself.

[0101] The exposure system includes a laser device 100 and an exposure device 200. Figure 1 The laser device 100 is schematically shown in FIG. Figure 2 The exposure device 200 is schematically shown in FIG.

[0102] The laser device 100 includes a laser control processor 130 . The laser device 100 is configured to output pulse laser light toward the exposure device 200 .

[0103] 1.2 Exposure device 200

[0104] 1.2.1 Structure

[0105] like Figure 1 As shown, the exposure device 200 includes an illumination optical system 201 , a projection optical system 202 , and an exposure control processor 210 .

[0106] The illumination optical system 201 illuminates a reticle pattern of a reticle (not shown) arranged on the reticle stage RT with pulsed laser light incident from the laser device 100 .

[0107] The projection optical system 202 projects the pulsed laser light transmitted through the mask in a reduced size and forms 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.

[0108] The exposure control processor 210 is a processing device including a memory 212 storing a control program and a CPU (central processing unit) 211 executing the control program. The exposure control processor 210 is specially configured or programmed to execute various processes included in the present disclosure. The exposure control processor 210 controls the exposure device 200 and sends and receives various data and various signals to and from the laser control processor 130.

[0109] 1.2.2 Action

[0110] The exposure control processor 210 sets various parameters related to exposure conditions and controls the illumination optical system 201 and the projection optical system 202 .

[0111] The exposure control processor 210 transmits data of the target wavelength, data of the target value of the pulse energy, and a trigger signal to the laser control processor 130. The laser control processor 130 controls the laser device 100 according to these data and signals.

[0112] The exposure control processor 210 causes the reticle stage RT and the work stage WT to move in parallel in opposite directions in synchronization with each other, thereby exposing the workpiece with the pulsed laser light reflecting the reticle pattern.

[0113] The mask pattern is transferred onto the semiconductor wafer through this exposure process, and then the electronic device can be manufactured through multiple processes.

[0114] 1.3 Laser device 100

[0115] 1.3.1 Structure

[0116] like Figure 2 As shown, the laser device 100 includes a laser cavity 10, a charger 12, a pulse power module (PPM) 13, a narrowband device 14, an output coupling mirror 15, a light measuring device 17, and an optical shutter 18 in addition to a laser control processor 130. The narrowband device 14 and the output coupling mirror 15 constitute an optical resonator.

[0117] The laser cavity 10 is disposed on the optical path of the optical resonator and is provided with windows 10a and 10b.

[0118] The laser cavity 10 has a pair of electrodes 11a and 11b inside and contains laser gas which is a raw material of a laser medium. The laser medium is, for example, F2, ArF, KrF, XeCl or XeF.

[0119] The charger 12 holds electric energy for supplying to the pulse power module 13. The pulse power module 13 includes a switch 13a.

[0120] The bandwidth narrowing device 14 includes wavelength selection elements such as prisms 41 and 42 and gratings 51 and 52 described later. The bandwidth narrowing device 14 is sometimes referred to as a bandwidth narrowing module.

[0121] The output coupling mirror 15 is formed by a partially reflecting mirror.

[0122] The optical measuring device 17 includes a beam splitter 17a and a sensor unit 17b. The beam splitter 17a is arranged on the optical path of the pulse laser output from the output coupling mirror 15. The beam splitter 17a is configured to transmit a part of the pulse laser with high transmittance and reflect the other part of the pulse laser to enter the sensor unit 17b. The sensor unit 17b includes a reference Figure 5 The energy sensor 17e, and the spectroscopic sensors 17f and 17g will be described later.

[0123] The shutter 18 is arranged on the optical path of the pulse laser after passing through the beam splitter 17a. When the shutter 18 is closed, the pulse laser after passing through the beam splitter 17a is blocked and does not enter the exposure device 200. When the shutter 18 is opened, the pulse laser after passing through the beam splitter 17a is not blocked and enters the exposure device 200.

[0124] The laser control processor 130 is a processing device including a memory 132 storing a control program and a CPU 131 executing the control program. The laser control processor 130 is specially configured or programmed to execute various processes included in the present disclosure. The memory 132 corresponds to the storage device in the present disclosure.

[0125] 1.3.2 Action

[0126] The laser control processor 130 obtains the target wavelength data from the exposure control processor 210. The laser control processor 130 sends an initial setting signal according to the target wavelength to the narrowband device 14. After starting to output the pulsed laser, the laser control processor 130 receives the wavelength measurement data from the light measuring device 17, and sends a feedback control signal to the narrowband device 14 according to the target wavelength and the wavelength measurement data.

[0127] The laser control processor 130 obtains data of the target value of pulse energy from the exposure control processor 210. The laser control processor 130 sends an initial setting signal of the charging voltage V to the charger 12 according to the target value of pulse energy. After starting to output pulse laser, the laser control processor 130 receives the measurement data of pulse energy from the light measuring device 17, and sends a feedback control signal of the charging voltage V to the charger 12 according to the target value of pulse energy and the measurement data of pulse energy.

[0128] The laser control processor 130 receives the trigger signal from the exposure control processor 210. The laser control processor 130 transmits an oscillation trigger signal based on the trigger signal to the switch 13a of the pulse power module 13.

[0129] The switch 13a is turned on upon receiving an oscillation trigger signal from the laser control processor 130. When the switch 13a is turned on, the pulse power module 13 generates a pulsed high voltage based on the electric energy held by the charger 12. The pulse power module 13 applies the high voltage to the electrodes 11a and 11b.

[0130] When a high voltage is applied to the electrodes 11a and 11b, a discharge is generated between the electrodes 11a and 11b. The laser gas in the laser cavity 10 is excited by the energy of the discharge and transitions to a high energy level. Then, when the excited laser gas transitions to a low energy level, light of a wavelength corresponding to the energy level difference is emitted.

[0131] The light generated in the laser cavity 10 is emitted to the outside of the laser cavity 10 through the windows 10a and 10b. The light emitted from the window 10a is incident on the narrowband device 14 as a beam. The light near the desired wavelength of the light incident on the narrowband device 14 is folded back by the narrowband device 14 and returns to the laser cavity 10.

[0132] The output coupling mirror 15 transmits a part of the light emitted from the window 10 b and outputs it, and reflects the other part and returns it to the laser cavity 10 .

[0133] Thus, the light emitted from the laser cavity 10 reciprocates between the narrowband device 14 and the output coupling mirror 15. The light is amplified each time it passes through the discharge space between the pair of electrodes 11a and 11b. The narrowband light thus oscillated is output from the output coupling mirror 15 as pulsed laser light.

[0134] The pulse laser light outputted from the laser device 100 is incident on the exposure device 200 .

[0135] 1.4 Narrowband Devices 14

[0136] 1.4.1 Structure

[0137] Figure 3 and Figure 4 The structure of the narrowband device 14 in the comparative example is schematically shown. Figure 3 and Figure 4 , an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other are respectively shown. Figure 3 The narrowband device 14 is shown as viewed in the +Y direction. Figure 4 The narrowing device 14 is shown as viewed in the -X direction. The +Y direction and the -Y direction are in line with the electrodes 11a and 11b (see Figure 2 The −Z direction is consistent with the direction in which the light beam emitted from the window 10a travels. The +Z direction is consistent with the direction in which the pulse laser light emitted from the window 10b and outputted via the output coupling mirror 15 travels.

[0138] The narrowband device 14 includes prisms 41 and 42 and a grating system 50 .

[0139] 1.4.1.1 Prisms 41 and 42

[0140] The prism 41 is disposed on the optical path of the light beam emitted from the window 10 a . The prism 41 is supported by a holder 411 .

[0141] The prism 42 is disposed on the optical path of the light beam that has passed through the prism 41. The prism 42 is supported by a holder 421.

[0142] The prisms 41 and 42 are arranged so that the surfaces of the prisms 41 and 42 through which the light beams are incident and emitted are parallel to the Y-axis.

[0143] 1.4.1.2 Grating system 50

[0144] The grating system 50 includes gratings 51 and 52. The gratings 51 and 52 are arranged at different positions in the Y-axis direction in the optical path of the light beam after passing through the prism 42. The directions of the grooves of the gratings 51 and 52 are consistent with the Y-axis direction. The positions of the gratings 51 and 52 are set so that the light beam after passing through the prism 42 crosses the gratings 51 and 52 and enters the gratings 51 and 52.

[0145] The gratings 51 and 52 are supported by a holder 511. The grating 51 is rotatable around an axis parallel to the Y axis by a first rotating table 512. The grating 52 is rotatable around an axis parallel to the Y axis by a second rotating table 522.

[0146] 1.4.2 Action

[0147] The light beam emitted from the window 10a changes its traveling direction in a plane parallel to the plane perpendicular to the Y axis, that is, the XZ plane, through the prisms 41 and 42, respectively, and expands the beam width in a plane parallel to the XZ plane. As an example, the traveling direction of the light beam passing through both the prisms 41 and 42 and heading toward the gratings 51 and 52 is substantially consistent with the -Z direction.

[0148] The light incident on the gratings 51 and 52 from the prism 42 is reflected by the multiple grooves of the gratings 51 and 52, and diffracted in the direction corresponding to the wavelength of the light. Thus, the light reflected by the multiple grooves of the gratings 51 and 52 is dispersed in a plane parallel to the XZ plane. The grating 51 is configured in a Littrow manner so that the incident angle of the light beam incident on the grating 51 from the prism 42 and the diffraction angle of the diffracted light of the desired wavelength λ1 are consistent. The grating 52 is configured in a Littrow manner so that the incident angle of the light beam incident on the grating 52 from the prism 42 and the diffraction angle of the diffracted light of the desired wavelength λ2 are consistent. In the case where the incident angles of the light beams incident on the gratings 51 and 52 from the prism 42 are different from each other, a wavelength difference is generated between the wavelength λ1 of the diffracted light returned from the grating 51 to the prism 42 and the wavelength λ2 of the diffracted light returned from the grating 52 to the prism 42.

[0149] exist Figure 3 and Figure 4 In FIG. 1 , the dotted arrows representing the light beams only show the direction from the prism 41 toward the gratings 51 and 52 , but the light beam of the selected wavelength of the narrowband device 14 moves from the gratings 51 and 52 toward the prism 41 in the opposite path to these dotted arrows.

[0150] The prisms 42 and 41 reduce the beam width of the light returning from the gratings 51 and 52 in a plane parallel to the XZ plane, and return the light into the laser cavity 10 through the window 10 a.

[0151] The first rotating stage 512 and the second rotating stage 522 are controlled by the laser control processor 130 .

[0152] When the first rotating stage 512 slightly rotates the grating 51, the incident angle of the light beam incident on the grating 51 from the prism 42 slightly changes. As a result, the wavelength λ1 changes.

[0153] When the second rotating stage 522 slightly rotates the grating 52, the incident angle of the light beam incident on the grating 52 from the prism 42 slightly changes. As a result, the wavelength λ2 changes.

[0154] The exposure control processor 210 sends the target wavelength λ1t of wavelength λ1 and the target wavelength λ2t of wavelength λ2 to the laser control processor 130. Here, wavelength λ1 and wavelength λ2 are wavelengths that are imaged at two locations, the upper surface and the bottom surface of the resist film applied to the semiconductor wafer, for example.

[0155] The laser control processor 130 controls the first rotating stage 512 according to the target wavelength λ1t. Thus, the first rotating stage 512 changes the posture of the grating 51 and adjusts the incident angle of the light beam with respect to the grating 51.

[0156] The laser control processor 130 controls the second rotating stage 522 according to the target wavelength λ2t. Thus, the second rotating stage 522 changes the posture of the grating 52 and adjusts the incident angle of the light beam with respect to the grating 52.

[0157] Through the above structure and operation, the wavelength λ1 and the wavelength λ2 of the light beam emitted from the window 10a of the laser cavity 10 are selected and returned to the laser cavity 10. Thus, the laser device 100 can perform dual-wavelength oscillation. By controlling the first rotating stage 512 and the second rotating stage 522, the wavelength λ1 and the wavelength λ2 can also be set separately.

[0158] The pulsed laser light outputted from the laser device 100 by dual-wavelength oscillation includes two wavelength components, namely, wavelength λ1 and wavelength λ2. The pulsed laser light includes pulses in which the first pulsed laser light having wavelength λ1 and the second pulsed laser light having wavelength λ2 overlap in time and space. Alternatively, the first pulsed laser light having wavelength λ1 and the second pulsed laser light having wavelength λ2 may overlap in time but not in space.

[0159] Exposure device 200 (see Figure 1 ) depends on the wavelength of the pulsed laser. The pulsed laser output from the laser device 100 by dual-wavelength oscillation can form an image at two different positions in the direction of the optical path axis of the pulsed laser in the workpiece stage WT of the exposure device 200, and can substantially increase the depth of focus. For example, when exposing a thick resist film, the imaging performance in the thickness direction of the resist film can also be maintained.

[0160] 1.5 Light measuring device 17

[0161] 1.5.1 Structure

[0162] Figure 5The structure of the optical measuring device 17 in the comparative example is schematically shown. The sensor unit 17b included in the optical measuring device 17 includes beam splitters 17c and 17d, an energy sensor 17e, and spectroscopic sensors 17f and 17g. The beam splitter 17c is arranged on the optical path of the pulsed laser reflected by the beam splitter 17a, and is configured to reflect a part of the pulsed laser and transmit the other part.

[0163] The energy sensor 17e is arranged on the optical path of the pulse laser beam reflected by the beam splitter 17c. The energy sensor 17e includes a diffuser 17h and a photodiode 17i.

[0164] The beam splitter 17 d is disposed on the optical path of the pulse laser light after passing through the beam splitter 17 c , and is configured to reflect a part of the pulse laser light and transmit the other part.

[0165] The spectroscopic sensor 17f is disposed on the optical path of the pulse laser beam reflected by the beam splitter 17d. The spectroscopic sensor 17f includes a diffuser 17j, an etalon 17k, a condenser lens 17m, and an image sensor 17n.

[0166] The spectroscopic sensor 17g is disposed on the optical path of the pulse laser beam after passing through the beam splitter 17d. The spectroscopic sensor 17g includes a diffuser 17o, an etalon 17p, a condenser lens 17q, and an image sensor 17r.

[0167] 1.5.2 Action

[0168] In the energy sensor 17e, the pulsed laser beam transmitted through the diffuser 17h enters the photodiode 17i. The photodiode 17i generates a current corresponding to the light intensity of the pulsed laser beam. The current is integrated over the time of one pulse of the pulsed laser beam to obtain the pulse energy of the pulsed laser beam.

[0169] In the spectroscopic sensor 17f, the pulse laser light that has sequentially passed through the diffuser 17j, the etalon 17k, and the condenser lens 17m forms interference fringes in the image sensor 17n.

[0170] Figure 6 1 is a graph showing an example of the measurement result of interference fringes by the spectroscopic sensor 17f included in the optical measuring device 17. Figure 6 and the following Figure 7 , Figure 8 , Figure 19 to Figure 21 In FIG. 1 , the horizontal axis represents the radius L of the interference fringe, and the vertical axis represents the light intensity I. All units are arbitrary units. The central wavelength of the pulsed laser can be calculated from the value of the L axis where the light intensity I is the peak.

[0171] The operation of the spectroscopic sensor 17g is the same as that of the spectroscopic sensor 17f. In either the spectroscopic sensor 17g or the spectroscopic sensor 17f, the radius L of the interference fringes changes periodically according to the wavelength change of the pulsed laser. The range of wavelength change corresponding to one cycle of the periodic change is called the free spectrum range (FSR). When the free spectrum range of the spectroscopic sensor 17g is larger than the free spectrum range of the spectroscopic sensor 17f, the spectroscopic sensor 17g can perform a wide range of wavelength measurement, and the spectroscopic sensor 17f can perform a high-precision wavelength measurement. By combining them, a wide range and high-precision wavelength measurement can be performed.

[0172] 1.6 Issues of Comparative Example

[0173] Figure 7 This is a graph showing an example of the measurement results of interference fringes when a pulsed laser beam with a wavelength λ1 and a pulsed laser beam with a wavelength λ2 are incident on the spectroscopic sensor 17f. Even if the wavelength λ1 and the wavelength λ2 are close in value, when they are measured separately, the peak values ​​of the light intensity I can be determined separately and the wavelength can be measured with high accuracy.

[0174] Figure 8 This is a graph showing an example of the measurement result of interference fringes when the pulsed laser light of the wavelength λ1 and the pulsed laser light of the wavelength λ2 are simultaneously incident on the spectroscopic sensor 17 f . Figure 8 The waveform shown is roughly equivalent to Figure 7 The waveform of the interference fringe of wavelength λ1 and the waveform of the interference fringe of wavelength λ2 in the image are combined. When the wavelengths λ1 and λ2 are close in value, it is sometimes difficult to Figure 8 The measurement results shown identify the peak value of the light intensity I. In this case, it is difficult to measure the wavelength λ1 and the wavelength λ2.

[0175] In some embodiments described below, encoders 513 and 523 are mounted on the first rotating stage 512 for changing the wavelength λ1 and the second rotating stage 522 for changing the wavelength λ2, respectively. A first relationship λ1θ1 between the position θ1 of the first rotating stage 512 and the wavelength λ1 and a second relationship λ2θ2 between the position θ2 of the second rotating stage 522 and the wavelength λ2 are stored in the memory 132. The first rotating stage 512 is controlled based on the first relationship λ1θ1 and the position θ1 of the first rotating stage 512 measured by the encoder 513, and the second rotating stage 522 is controlled based on the second relationship λ2θ2 and the position θ2 of the second rotating stage 522 measured by the encoder 523.

[0176] 2. Laser device that adjusts wavelength by controlling a rotating stage based on encoder output

[0177] 2.1 Structure

[0178] Fig. 9 and Fig.10 The configuration of the bandwidth narrowing device 14a in the first embodiment is schematically shown. Fig. 9 The narrowband device 14a is shown as viewed in the +Y direction. Fig.10 The band-narrowing device 14a is shown as viewed in the -X direction.

[0179] The bandwidth narrowing device 14a includes a grating system 50a instead of the grating system 50. Furthermore, the bandwidth narrowing device 14a includes a beam splitting optical system 60a between the prism 42 and the grating system 50a.

[0180] In the grating system 50a, an encoder 513 is mounted on the first rotating table 512 of the grating 51. An encoder 523 is mounted on the second rotating table 522 of the grating 52. Fig.10 , the first rotating table 512 and the encoder 513 are shown separately, but they can also be Fig.13 The second rotating table 522 and the encoder 523 are integrated as described later.

[0181] In the first embodiment, the grating 51 is equivalent to the first optical element in the present disclosure, and the grating 52 is equivalent to the second optical element in the present disclosure. The first rotating table 512 is equivalent to the first actuator in the present disclosure, and the second rotating table 522 is equivalent to the second actuator in the present disclosure. The encoder 513 is equivalent to the first encoder in the present disclosure, and the encoder 523 is equivalent to the second encoder in the present disclosure.

[0182] The beam splitting optical system 60 a includes a parallel plane substrate 61 .

[0183] The parallel plane substrate 61 can be arranged at a position overlapping a part of the cross section of the optical path of the light beam after passing through the prism 42. The parallel plane substrate 61 is supported by a holder 611. The parallel plane substrate 61 is configured to be movable in the -Y direction and the +Y direction by a linear stage 612. An encoder 613 is mounted on the linear stage 612.

[0184] In the first embodiment, the linear stage 612 corresponds to the third actuator in the present disclosure. The encoder 613 corresponds to the third encoder in the present disclosure.

[0185] The parallel plane substrate 61 includes an incident surface 615 for a portion of the light beam after passing through the prism 42 to be incident, and an exit surface 614 for the light beam incident on the parallel plane substrate 61 through the incident surface 615 to be emitted from the inside of the parallel plane substrate 61 toward the grating 52 (see Fig.10). The incident surface 615 and the exit surface 614 are both parallel to the X-axis and inclined relative to the Y-axis. The incident surface 615 and the exit surface 614 are parallel to each other.

[0186] The plane-parallel substrate 61 further includes an end face 616 on the +Y side. The end face 616 forms an acute angle with the emission surface 614. The end face 616 may also be parallel to the XZ plane.

[0187] 2.2 Action

[0188] like Fig.10 As shown, the first part B1 of the light beam after passing through the prism 42 is incident on the grating 51 through the outside of the parallel plane substrate 61, and the second part B2 of the light beam is incident on the grating 52 through the inside of the parallel plane substrate 61. At this time, the parallel plane substrate 61 causes the optical path axis of the second part B2 of the light beam to shift in the -Y direction relative to the optical path axis of the first part B1.

[0189] When the linear stage 612 moves the parallel plane substrate 61 in the +Y direction to increase the second portion B2 of the light beam incident on the parallel plane substrate 61 , the light incident on the grating 52 increases.

[0190] When the linear stage 612 moves the parallel plane substrate 61 in the −Y direction to reduce the second portion B2 of the light beam incident on the parallel plane substrate 61 , the light incident on the grating 52 is reduced.

[0191] In this way, the linear stage 612 changes the position of the plane-parallel substrate 61 in the Y-axis direction, thereby changing the ratio of the first portion B1 to the second portion B2 and changing the intensity ratio R of the wavelength λ1 to the wavelength λ2.

[0192] The moving direction of the parallel plane substrate 61 by the linear stage 612 may not be the Y-axis direction. The linear stage 612 may move the parallel plane substrate 61 in a direction intersecting the XZ plane which is a plane perpendicular to the Y-axis.

[0193] The exposure control processor 210 sends the target wavelength λ1t, the target wavelength λ2t, and the target intensity ratio Rt to the laser control processor 130 .

[0194] The laser control processor 130 controls the first rotating stage 512 according to the target wavelength λ1t. Thus, the first rotating stage 512 changes the posture of the grating 51 and adjusts the wavelength λ1 selected by the grating 51.

[0195] The laser control processor 130 controls the second rotating stage 522 according to the target wavelength λ2t. Thus, the second rotating stage 522 changes the posture of the grating 52 to adjust the wavelength λ2 selected by the grating 52.

[0196] The laser control processor 130 controls the linear stage 612 according to the target intensity ratio Rt. Thus, the linear stage 612 adjusts the position of the parallel plane substrate 61 and adjusts the intensity ratio R of the wavelength λ1 to the wavelength λ2.

[0197] Fig.11 The arrangement of the parallel plane substrate 61 is shown in the first embodiment when the entire light beam is incident on the grating 51 as the first portion B1. The linear stage 612 may retract the parallel plane substrate 61 from the optical path of the light beam, thereby making the ratio of the second portion B2 to the first portion B1 zero.

[0198] Fig.12 The configuration of the parallel plane substrate 61 in the first embodiment is shown when the entire light beam enters the grating 52 as the second portion B2. The linear stage 612 may be configured such that the ratio of the first portion B1 to the second portion B2 is zero by configuring the parallel plane substrate 61 at a position where the entire light beam passes.

[0199] 2.3 Encoder Example

[0200] Fig.13 The following is a configuration example of the first rotating table 512 and the encoder 513 in the first embodiment. The first rotating table 512 and the encoder 513 may be accommodated in a common housing 519 .

[0201] The first rotating table 512 includes a rotor 514 and a stator 515. The rotor 514 is fixed to the rotating shaft A supported by the bearing 516, and rotates together with the rotating shaft A. Although the details of the rotor 514 and the stator 515 are not shown in the figure, for example, the rotor 514 includes a permanent magnet and the stator 515 includes an electromagnet. The rotor 514 rotates by switching the magnetic field generated by the electromagnet of the stator 515.

[0202] The encoder 513 includes a circular plate 517 and a measuring head 518. The circular plate 517 is fixed to the rotation axis A and rotates together with the rotation axis A. Although the details of the circular plate 517 and the measuring head 518 are not shown in the figure, for example, the circular plate 517 includes a holographic diffraction grating. In addition, for example, the measuring head 518 includes a laser diode, an optical system that causes interference between +1st diffracted light and -1st diffracted light based on the holographic diffraction grating of light output from the laser diode, and a photodetector that measures the interference light.

[0203] When the rotation axis A is rotated by the first rotating table 512, the circular plate 517 rotates, and the holographic diffraction grating moves in the circumferential direction of the circular plate 517 relative to the measuring head 518. The variation pattern of the intensity of the interference light relative to the moving distance of the holographic diffraction grating is approximately a sine curve. Therefore, by measuring the intensity of the interference light, the moving distance shorter than the length of one pitch of the holographic diffraction grating can be measured with high precision.

[0204] In addition, an optical system has been proposed in which the light and dark of interference light are repeated multiple times every time the holographic diffraction grating moves by one pitch. If such an optical system is used, the resolution can be further improved.

[0205] exist Fig.13 Although an example of the first rotating table 512 and the encoder 513 is shown in FIG. 5 , the second rotating table 522 and the encoder 523 may be the same.

[0206] In addition, the linear stage 612 is different from the first rotating stage 512 in that the parallel plane substrate 61 is linearly moved instead of rotating the grating 51, and the encoder 613 is different from the encoder 513 in that the holographic diffraction grating is not moved in the circumferential direction but moves linearly. However, the principle of measuring the moving distance of the holographic diffraction grating can be the same as that of the encoder 513, so detailed description is omitted.

[0207] 2.4 Example of intensity ratio R

[0208] Fig.14 Graph showing an example of a spectrum waveform of the pulsed laser light output from the laser device 100 in the first embodiment. Fig.14 , the horizontal axis represents the wavelength λ, and the vertical axis represents the light intensity I. The pulse laser includes a wavelength component of wavelength λ1 and a wavelength component of wavelength λ2. The wavelength λ1 corresponds to the first wavelength component in the present disclosure, and the wavelength λ2 corresponds to the second wavelength component in the present disclosure.

[0209] When the pulse energy E of the wavelength component of wavelength λ1 is Eλ1 and the pulse energy E of the wavelength component of wavelength λ2 is Eλ2, the intensity ratio R of the wavelength component of wavelength λ1 to the wavelength component of wavelength λ2 is defined by the following formula.

[0210] R=Eλ1 / (Eλ1+Eλ2)

[0211] Alternatively, the intensity ratio R may be defined by the following formula.

[0212] R=Eλ1 / Eλ2

[0213] Alternatively, the intensity ratio R can also be expressed by the ratio Eλ1:Eλ2.

[0214] exist Fig.14 In the spectral waveform shown, the integral value S of the light intensity I of the wavelength component with wavelength λ1 as the center wavelength is set to Sλ1, and the integral value S of the light intensity I of the wavelength component with wavelength λ2 as the center wavelength is set to Sλ2. The intensity ratio R can also be defined by the following formula.

[0215] R=Sλ1 / (Sλ1+Sλ2)

[0216] Alternatively, the intensity ratio R may be defined by the following formula.

[0217] R=Sλ1 / Sλ2

[0218] Alternatively, the intensity ratio R can also be expressed by the ratio Sλ1:Sλ2.

[0219] When the spectral line widths of the wavelength component with wavelength λ1 as the center wavelength and the wavelength component with wavelength λ2 as the center wavelength are the same, the peak value of the light intensity I and the integrated value S are in a proportional relationship in these wavelength components. Therefore, when the peak value of the light intensity I of the wavelength component with wavelength λ1 is set to Iλ1 and the peak value of the light intensity I of the wavelength component with wavelength λ2 is set to Iλ2, the intensity ratio R can also be defined by the following formula.

[0220] R=Iλ1 / (Iλ1+Iλ2)

[0221] Alternatively, the intensity ratio R may be defined by the following formula.

[0222] R=Iλ1 / Iλ2

[0223] Alternatively, the intensity ratio R may be expressed by the ratio Iλ1:Iλ2.

[0224] 2.5 Operation of the Laser Control Processor 130

[0225] 2.5.1 Main Process

[0226] Fig.15 1 is a flowchart showing the operation of the laser control processor 130 in the first embodiment. As described below, after acquiring data for controlling the wavelengths λ1 and λ2 and the intensity ratio R, the laser control processor 130 controls the laser device 100 to output exposure light.

[0227] In S11 , the laser control processor 130 closes the shutter 18 , thereby preventing the pulse laser from entering the exposure device 200 .

[0228] In S12, the laser control processor 130 stores the positions of various actuators measured by various encoders. The various actuators include the first rotating table 512, the second rotating table 522, and the linear table 612. The various encoders include encoders 513, 523, and 623. The rotation angle based on the specified position of the first rotating table 512 is set to the position θ1 of the first rotating table 512. The position θ1 is measured by the encoder 513. The rotation angle based on the specified position of the second rotating table 522 is set to the position θ2 of the second rotating table 522. The position θ2 is measured by the encoder 523. The moving distance based on the specified position of the linear table 612 is set to the position Y of the linear table 612. The position Y is measured by the encoder 613.

[0229] In S13, the laser control processor 130 performs wavelength λ1 calibration. The laser control processor 130 obtains data for adjusting the wavelength λ1 by controlling the position θ1 through the wavelength λ1 calibration. For details of the wavelength λ1 calibration, refer to Fig.16 This will be described later.

[0230] In S14, the laser control processor 130 performs wavelength λ2 calibration. The laser control processor 130 obtains data for adjusting the wavelength λ2 by controlling the position θ2 through the wavelength λ2 calibration. For details of the wavelength λ2 calibration, refer to Fig.17 This will be described later.

[0231] In S16, the laser control processor 130 performs the intensity ratio R calibration. The laser control processor 130 obtains data for adjusting the intensity ratio R for controlling the position Y through the intensity ratio R calibration. For details of the intensity ratio R calibration, refer to Fig.18 This will be described later.

[0232] In S18, the laser control processor 130 returns the various actuators to the positions stored in S12.

[0233] In S19 , the laser control processor 130 opens the shutter 18 and sends a preparation OK signal to the exposure control processor 210 of the exposure device 200 .

[0234] In S20, the laser control processor 130 reads the parameters stored in various calibrations. The various calibrations include wavelength λ1 calibration, wavelength λ2 calibration, and intensity ratio R calibration. The parameters stored in the various calibrations include the parameters of the first relationship λ1θ1, the parameters of the second relationship λ2θ2, and the parameters of the third relationship RY. Various calibrations and parameter references Figure 16 to Figure 18 This will be described later.

[0235] In S21, the laser control processor 130 outputs exposure light according to various signals received from the exposure control processor 210. For details of the output of exposure light, refer to Fig.25 This will be described later.

[0236] In S22, the laser control processor 130 determines whether a pause signal is received from the exposure control processor 210. The pause signal is a signal notifying that exposure is not performed when, for example, a mask is replaced in the exposure apparatus 200 or a semiconductor wafer is replaced.

[0237] When the pause signal is not received ( S22 : NO), the laser control processor 130 returns the process to S21 .

[0238] When receiving the pause signal ( S22 : YES), the laser control processor 130 advances the process to S23 .

[0239] In S23, the laser control processor 130 sends a preparation NOK signal to the exposure control processor 210. Then, the laser control processor 130 returns the process to S11.

[0240] 2.5.2 Wavelength λ1 Calibration

[0241] Fig.16 This is a flowchart showing the process of wavelength λ1 calibration in the first embodiment. Fig.16 The processing shown is equivalent to Fig.15 The S13 subroutine.

[0242] In S131, the laser control processor 130 sets the position Y of the linear stage 612 to the first position Ymin. Fig.11 As shown in FIG. 1 , the parallel plane substrate 61 moves to a position away from the optical path of the light beam. Therefore, the ratio of the wavelength component of the wavelength λ1 in the pulse laser light is greater than the ratio of the wavelength component of the wavelength λ2.

[0243] In S132 , the laser control processor 130 sets the position θ1 of the first rotating table 512 to θ1min. θ1min is, for example, the minimum value of θ1 within the movable range of the first rotating table 512 .

[0244] In S133, the laser control processor 130 sends an oscillation trigger signal to the switch 13a of the pulse power module 13 (refer to Figure 2 ) to cause the laser device 100 to oscillate. The laser control processor 130 does not receive a trigger signal from the exposure control processor 210, but outputs the oscillation trigger signal.

[0245] In S134 , the laser control processor 130 uses the light measuring device 17 to measure the wavelength λ1.

[0246] In S135 , the laser control processor 130 associates the position θ1 with the wavelength λ1 and stores them in the memory 132 .

[0247] In S136, the laser control processor 130 sets the position θ1 to the next position θ1+Δθ1. Δθ1 is the movement amount of the position θ1 for wavelength λ1 calibration.

[0248] In S137 , the laser control processor 130 determines whether the value indicating the position θ1 is smaller than θ1max. θ1max is, for example, the maximum value of θ1 within the movable range of the first rotating table 512 .

[0249] When the value indicating the position θ1 is smaller than θ1max ( S137 : YES), the laser control processor 130 returns the process to S133 .

[0250] When the value indicating the position θ1 is equal to or greater than θ1max ( S137 : NO), the laser control processor 130 advances the process to S138 .

[0251] In S138 , the laser control processor 130 calculates an equation representing a first relationship λ1θ1 between the position θ1 of the first rotating table 512 measured by the encoder 513 and the wavelength λ1 measured by the optical measuring device 17 .

[0252] In S139, the laser control processor 130 stores the parameters of the first relationship λ1θ1 in the memory 132. The parameters of the first relationship λ1θ1 are, for example, coefficients of an equation representing the first relationship λ1θ1.

[0253] After S139, the laser control processor 130 ends the processing of this flowchart and returns to Fig.15 Processing shown.

[0254] Fig. 22 FIG. 1 shows an example of the first relationship λ1θ1 obtained by wavelength λ1 calibration. When the position θ1 of the first rotating stage 512 is changed from θ1min to θ1max, the posture of the grating 51 changes, and the wavelength λ1 changes. The laser control processor 130 may also Fig.16 In S138 of , the following approximate expression is generated which represents the relationship between the position θ1 of the first rotating table 512 measured by the encoder 513 and the wavelength λ1 measured by the optical measuring device 17 .

[0255] λ1=a1·θ1+b1

[0256] In addition, you can also Fig.16 In S139 , the parameters such as coefficients a1 and b1 included in this approximate formula are stored in the memory 132 .

[0257] 2.5.3 Wavelength λ2 Calibration

[0258] Fig.17 1 is a flowchart showing the process of wavelength λ2 calibration in the first embodiment. Fig.17 The processing shown is equivalent to Fig.15 The S14 subroutine.

[0259] In S141, the laser control processor 130 sets the position Y of the linear stage 612 to the second position Ymax. Fig.12 As shown, the parallel plane substrate 61 moves to the position where the entire light beam passes. Therefore, the proportion of the wavelength component of the wavelength λ2 in the pulse laser light is greater than the proportion of the wavelength component of the wavelength λ1.

[0260] In the processing of S142 to S149, in addition to Fig.16 In addition to replacing the wavelength λ1 and the position θ1 with the wavelength λ2 and the position θ2, respectively, additional replacements are also performed, and detailed descriptions thereof are omitted.

[0261] Fig.23 FIG. 1 shows an example of the second relationship λ2θ2 obtained by the wavelength λ2 calibration. When the position θ2 of the second rotating stage 522 is changed from θ2min to θ2max, the posture of the grating 52 changes, and the wavelength λ2 changes. The laser control processor 130 may also Fig.17 In S148 of FIG. 14 , the following approximate expression is generated to express the relationship between the position θ2 of the second rotating table 522 measured by the encoder 523 and the wavelength λ2 measured by the optical measuring device 17 .

[0262] λ2=a2·θ2+b2

[0263] In addition, you can also Fig.17 In S149, the parameters such as coefficients a2 and b2 included in this approximate formula are stored in the memory 132.

[0264] 2.5.4 Intensity ratio R calibration

[0265] Fig.18 This is a flowchart showing the process of intensity ratio R calibration in the first embodiment. Fig.18 The processing shown is equivalent to Fig.15 The S16 subroutine.

[0266] In S160, the laser control processor 130 sets the position θ1 of the first rotating stage 512 so that the wavelength λ1 becomes the first measurement wavelength. As the first measurement wavelength, for example, a value close to the wavelength of the pulsed laser used as exposure light is selected. The position θ1 may also be calibrated using the wavelength λ1 (see Fig.16Alternatively, the position Y of the linear stage 612 may be set to the first position Ymin, and laser oscillation may be actually performed, and the position θ1 may be set so that the wavelength λ1 measured by the optical measuring device 17 becomes the first measurement wavelength.

[0267] In S161, the laser control processor 130 sets the position θ2 of the second rotating stage 522 so that the wavelength λ2 becomes the second measurement wavelength λ1+FSR / 2. The second measurement wavelength is a value obtained by adding half of the free spectrum range to the first measurement wavelength. That is, the wavelength λ1 and the wavelength λ2 are set so that the wavelength difference between the wavelength λ1 and the wavelength λ2 becomes half of the free spectrum range. Figure 6 When the free spectral range of the spectroscopic sensor 17g shown is larger than the free spectral range of the spectroscopic sensor 17f, the wavelength difference between the wavelength λ1 and the wavelength λ2 may be set to half the free spectral range of the spectroscopic sensor 17f.

[0268] Fig.19 This is a graph showing an example of the measurement results of interference fringes when pulsed lasers of wavelength λ1 and wavelength λ2 having a wavelength difference of half the free spectrum range are incident on the spectroscopic sensor 17f. When the wavelength difference is set to half the free spectrum range, the peak of the interference fringes of wavelength λ1 and the peak of the interference fringes of wavelength λ2 appear alternately with a large interval between them.

[0269] Fig. 20 and Fig.21 This is a graph showing an example of the measurement result of interference fringes when pulsed laser beams of wavelength λ1 and wavelength λ2 having a wavelength difference of half the free spectral range are simultaneously incident on the spectroscopic sensor 17 f . Fig. 20 The waveform shown is roughly equivalent to Fig.19 The composite waveform of the interference fringes with wavelength λ1 and the interference fringes with wavelength λ2.

[0270] Refer again Fig.18 In S162, the laser control processor 130 sets the position Y of the linear stage 612 to the first position Ymin.

[0271] In S163, the laser control processor 130 sends an oscillation trigger signal to the switch 13a of the pulse power module 13 to cause the laser device 100 to oscillate. This process is similar to S133 (see Fig.16 )same.

[0272] In S164 , the laser control processor 130 measures the intensity ratio R using the light measuring device 17 .

[0273] Fig. 20An example of the measurement results of interference fringes when the intensity ratio R defined by Eλ1 / (Eλ1+Eλ2) is 1 / 2 is shown.

[0274] Fig.21 An example of the measurement result of interference fringes when the intensity ratio R defined by Eλ1 / (Eλ1+Eλ2) is 10 / 11 is shown.

[0275] according to Fig. 20 and Fig.21 It can be seen that when the wavelength difference between wavelength λ1 and wavelength λ2 is close to half of the free spectrum range, the peak of the interference fringe of wavelength λ1 and the peak of the interference fringe of wavelength λ2 can be distinguished and determined. If the first measurement wavelength and the second measurement wavelength are known, it may be easier to distinguish the interference fringes. If the interference fringes can be distinguished, the intensity ratio R can be calculated based on the value of the light intensity I of each interference fringes.

[0276] Refer again Fig.18 In S165 , the laser control processor 130 stores the position Y and the intensity ratio R in correspondence with each other in the memory 132 .

[0277] In S166, the laser control processor 130 sets the position Y to the next position Y+ΔY. ΔY is the movement amount of the position Y for the intensity ratio R calibration.

[0278] In S167, the laser control processor 130 determines whether the value representing the position Y is smaller than Ymax.

[0279] When the value indicating the position Y is smaller than Ymax ( S167 : YES), the laser control processor 130 returns the process to S163 .

[0280] When the value indicating the position Y is greater than or equal to Ymax ( S167 : NO), the laser control processor 130 advances the process to S168 .

[0281] In S168 , the laser control processor 130 calculates an equation representing a third relationship RY between the position Y of the linear stage 612 measured by the encoder 613 and the intensity ratio R measured by the light measuring device 17 .

[0282] In S169, the laser control processor 130 stores the parameters of the third relationship RY in the memory 132. The parameters of the third relationship RY are, for example, coefficients of an equation representing the third relationship RY.

[0283] After S169, the laser control processor 130 ends the processing of this flowchart and returns to Fig.15 Processing shown.

[0284] Fig.24An example of the third relationship RY obtained by the intensity ratio R calibration is shown. When the position Y of the linear stage 612 is changed from the first position Ymin to the second position Ymax, the position of the parallel plane substrate 61 changes, and the intensity ratio R changes. However, between Ymin and Ya, the intensity ratio R is 1. That is, a sufficient gap is ensured between the parallel plane substrate 61 and the light beam so that the wavelength λ1 is calibrated (see Fig.16 ), the light beam will not be incident on the parallel plane substrate 61. In addition, between Ya+1 / α and Ymax, the intensity ratio R is 0. That is, the end face 616 of the parallel plane substrate 61 is arranged below the lower end position of the light beam so that the light beam is calibrated at the wavelength λ2 (refer to Fig.17 ) in which the entire light beam is incident upon a parallel plane substrate 61.

[0285] The third relationship RY is expressed by, for example, the following equation.

[0286] R=1-α×(Y-Ya)

[0287] If Y is less than Ya, R is 1, and if Y is greater than Ya+1 / α, R is 0.

[0288] The laser control processor 130 may also be Fig.18 The formula representing the third relationship RY is generated in S168.

[0289] In addition, you can also Fig.18 In S169, the parameters such as coefficients α and Ya contained in this formula are stored in the memory 132.

[0290] 2.5.5 Exposure Light Output

[0291] Fig.25 This is a flowchart showing the process of outputting exposure light in the first embodiment. Fig.25 The processing shown is equivalent to Fig.15 The S21 subroutine.

[0292] In S212 , the laser control processor 130 reads in the target wavelengths λ1t and λ2t and the target intensity ratio Rt. The target wavelengths λ1t and λ2t and the target intensity ratio Rt may also be received from the exposure control processor 210 .

[0293] Alternatively, the laser control processor 130 may receive the target average wavelength (λ1t+λ2t) / 2 and the target wavelength difference λ1t-λ2t from the exposure control processor 210 instead of the target wavelengths λ1t and λ2t. Alternatively, the laser control processor 130 may receive the target wavelength λ1t and the target wavelength difference λ1t-λ2t from the exposure control processor 210. The laser control processor 130 may also calculate the target wavelengths λ1t and λ2t based on these values ​​received from the exposure control processor 210 and read in the calculation results.

[0294] In addition, laser control processor 130 may receive target pulse energies Eλ1t and Eλ2t for each wavelength component from exposure control processor 210 instead of target intensity ratio Rt. Laser control processor 130 may calculate target intensity ratio Rt based on these values ​​received from exposure control processor 210 and read the calculation result.

[0295] In S213 , the laser control processor 130 calculates the target position θ1t of the first rotating stage 512 , the target position θ2t of the second rotating stage 522 , and the target position Yt of the linear stage 612 .

[0296] The target position θ1 t is calculated based on the first relationship λ1θ1 obtained by the wavelength λ1 calibration and the target wavelength λ1 t received from the exposure control processor 210 .

[0297] The target position θ2 t is calculated based on the second relationship λ2θ2 obtained by the wavelength λ2 calibration and the target wavelength λ2 t received from the exposure control processor 210 .

[0298] The target position Yt is calculated based on the third relationship RY obtained by the intensity ratio R calibration and the target intensity ratio Rt received from the exposure control processor 210 .

[0299] In S214, the laser control processor 130 sets the positions θ1, θ2, and Y of the various actuators to the respective target positions θ1t, θ2t, and Yt. Then, the laser control processor 130 controls the various actuators as follows.

[0300] The laser control processor 130 controls the first rotating table 512 so that the position θ1 of the first rotating table 512 measured by the encoder 513 approaches the target position θ1t.

[0301] The laser control processor 130 controls the second rotating table 522 so that the position θ2 of the second rotating table 522 measured by the encoder 523 approaches the target position θ2t.

[0302] The laser control processor 130 controls the linear stage 612 so that the position Y of the linear stage 612 measured by the encoder 613 approaches the target position Yt.

[0303] In S215 , the laser control processor 130 determines whether a trigger signal is received from the exposure control processor 210 .

[0304] When the trigger signal is not received ( S215 : No), the laser control processor 130 stands by until a trigger signal is received.

[0305] When receiving the trigger signal ( S215 : YES), the laser control processor 130 advances the process to S216 .

[0306] In S216 , the laser control processor 130 sends an oscillation trigger signal to the switch 13 a of the pulse power module 13 , and controls the laser device 100 to perform laser oscillation.

[0307] After S216, the laser control processor 130 ends the processing of this flowchart and returns to Fig.15 Processing shown.

[0308] 2.6 Function

[0309] (1) According to the first embodiment, the laser device 100 includes: a grating 51 and a grating 52; a first rotating table 512, which changes the posture of the grating 51, thereby changing the wavelength λ1 contained in the pulsed laser; a second rotating table 522, which changes the posture of the grating 52, thereby changing the wavelength λ2 contained in the pulsed laser; an encoder 513, which measures the position θ1 of the first rotating table 512; an encoder 523, which measures the position θ2 of the second rotating table 522; and a laser control processor 130.

[0310] The laser control processor 130 reads a first relationship λ1θ1 between the position θ1 of the first rotating stage 512 and the wavelength λ1 and a second relationship λ2θ2 between the position θ2 of the second rotating stage 522 and the wavelength λ2 ( S20 ).

[0311] In addition, the laser control processor 130 controls the first rotating table 512 according to the first relationship λ1θ1 and the position θ1 of the first rotating table 512 measured by the encoder 513, and controls the second rotating table 522 according to the second relationship λ2θ2 and the position θ2 of the second rotating table 522 measured by the encoder 523 (S213, S214).

[0312] Thus, the first rotating table 512 is controlled according to the first relationship λ1θ1 and the output of the encoder 513, and the second rotating table 522 is controlled according to the second relationship λ2θ2 and the output of the encoder 523. Therefore, even if the wavelength λ1 and the wavelength λ2 are not measured when the exposure light is output, these wavelengths can be adjusted. Regarding the calculation of the wavelength, the data of the interference fringes obtained by the spectroscopic sensor are often subjected to a deconvolution process using the device function of the light measuring device 17. Generally, the calculation of the wavelength requires a time longer than the shortest oscillation period of the laser device 100. Therefore, it is difficult to control and output any two wavelengths for each pulse. However, according to the first embodiment, the wavelength λ1 and the wavelength λ2 are not measured when the exposure light is output, so the deconvolution process accompanying the wavelength calculation is not required when the exposure light is output. Therefore, it is possible to control and output any two wavelengths for each pulse.

[0313] (2) According to the first embodiment, the laser device 100 includes the optical measuring device 17 for measuring the wavelength λ1 and the wavelength λ2.

[0314] The laser control processor 130 measures the wavelength λ1 using the optical measuring device 17 (S134), and performs processing to store the relationship between the position θ1 of the first rotating table 512 and the wavelength λ1 measured by the encoder 513 as a first relationship λ1θ1 in the memory 132 (S138, S139).

[0315] Furthermore, the laser control processor 130 measures the wavelength λ2 using the optical measuring device 17 (S144), and performs processing for storing the relationship between the position θ2 of the second rotating table 522 and the wavelength λ2 measured by the encoder 523 as a second relationship λ2θ2 in the memory 132 (S148, S149).

[0316] Thus, a first relationship λ1θ1 between the wavelength λ1 measured by the optical measuring device 17 and the position θ1 of the first rotating table 512 measured by the encoder 513 is stored. In addition, a second relationship λ2θ2 between the wavelength λ2 measured by the optical measuring device 17 and the position θ2 of the second rotating table 522 measured by the encoder 523 is stored. Since the first relationship λ1θ1 and the second relationship λ2θ2 are measured and stored in advance in this way, the wavelengths λ1 and λ2 can be controlled with high accuracy using the encoders 513 and 523.

[0317] (3) According to the first embodiment, the laser device 100 includes the linear stage 612 that changes the intensity ratio R between the wavelength λ1 and the wavelength λ2.

[0318] The laser control processor 130 measures the wavelength λ1 (S134) using the optical measuring device 17 while the ratio of the wavelength λ1 is made larger than the ratio of the wavelength λ2 by the linear stage 612 (S131). The laser control processor 130 measures the wavelength λ2 (S144) using the optical measuring device 17 while the ratio of the wavelength λ2 is made larger than the ratio of the wavelength λ1 by the linear stage 612 (S141).

[0319] Thus, the intensity ratio R between the wavelength λ1 and the wavelength λ2 is changed to measure the wavelength λ1 and the wavelength λ2 individually, and therefore, these wavelengths can be measured with high accuracy.

[0320] (4) According to the first embodiment, the laser device 100 includes the linear stage 612 that changes the intensity ratio R between the wavelength λ1 and the wavelength λ2 , and the encoder 613 that measures the position Y of the linear stage 612 .

[0321] The laser control processor 130 reads the third relationship RY between the position Y of the linear stage 612 and the intensity ratio R ( S20 ), and controls the linear stage 612 based on the third relationship RY and the position Y of the linear stage 612 measured by the encoder 613 ( S213 , S214 ).

[0322] Thus, the linear stage 612 is controlled based on the third relationship RY and the output of the encoder 613. Therefore, when outputting exposure light, the intensity ratio R can be adjusted without measuring the intensity ratio R of the wavelength λ1 to the wavelength λ2.

[0323] (5) According to the first embodiment, the laser device 100 includes the optical measuring device 17 for measuring the intensity ratio R between the wavelength λ1 and the wavelength λ2. The laser control processor 130 measures the intensity ratio R using the optical measuring device 17 (S164), and stores the relationship between the position Y of the linear stage 612 measured by the encoder 613 and the intensity ratio R as the third relationship RY in the memory 132 (S168, S169).

[0324] Thus, the third relationship RY between the intensity ratio R measured by the light measuring device 17 and the position Y of the linear stage 612 measured by the encoder 613 is stored. Since the third relationship RY is measured and stored in advance in this way, the intensity ratio R using the encoder 613 can be controlled with high accuracy.

[0325] (6) According to the first embodiment, the laser control processor 130 controls the first rotating stage 512 and the second rotating stage 522 so that the wavelength difference between the wavelength λ1 and the wavelength λ2 approaches half of the free spectrum range of the optical measuring device 17 (S160, S161), and then uses the optical measuring device 17 to measure the intensity ratio R (S164).

[0326] Thus, by adjusting the wavelength difference between the wavelength λ1 and the wavelength λ2 so as to be close to half of the free spectrum range, even when both the wavelength λ1 and the wavelength λ2 are output simultaneously, the intensity ratio R thereof can be measured.

[0327] Regarding other aspects, the first embodiment is the same as the above-mentioned comparative example.

[0328] 3. Laser device with the third relationship RY selected based on repetition frequency f and charging voltage V

[0329] 3.1 Main Process

[0330] Fig.26 1 is a flowchart showing the operation of the laser control processor 130 in the second embodiment. The structure of the laser device 100 in the second embodiment is the same as that in the first embodiment. The second embodiment is different from the first embodiment in that the third relationship RY(f, V) calibration (S15b) is performed instead of the intensity ratio R calibration (S16). In addition, in the second embodiment, the output of exposure light (S21b) is performed instead of the output of exposure light (S21).

[0331] 3.2 Calibration of the third relation RY(f,V)

[0332] Fig. 27 : is a flowchart showing the process of calibrating the third relationship RY(f, V) in the second embodiment. Fig. 27 The processing shown is equivalent to Fig.26 The S15b subroutine.

[0333] In S151 , the laser control processor 130 sets the repetition frequency f of the pulsed laser to fmin. Here, fmin is the minimum value of the repetition frequency f that can be requested from the exposure control processor 210 .

[0334] In S152, the laser control processor 130 sends the charger 12 (refer to Figure 2 ) is set as Vmin. Here, Vmin is the minimum value of the charging voltage V corresponding to the range of pulse energy that can be requested from the exposure control processor 210.

[0335] Following S152, in S16, the laser control processor 130 performs an intensity ratio R calibration. The process of S16 is the same as the intensity ratio R calibration in the first embodiment. However, the intensity ratio R calibration in the second embodiment is different from the intensity ratio R calibration in the first embodiment in that, according to the loop process of this flowchart, the intensity ratio R calibration is performed multiple times compared with the wavelength λ1 calibration and the wavelength λ2 calibration.

[0336] Following S16, in S154, the laser control processor 130 sets the charging voltage V to the next value V+ΔV. ΔV is the amount of change in the charging voltage V for calibration of the third relationship RY(f, V).

[0337] In S155, the laser control processor 130 determines whether the charging voltage V is less than Vmax.

[0338] When the charging voltage V is lower than Vmax ( S155 : YES), the laser control processor 130 returns the process to S16 .

[0339] When the charging voltage V is equal to or greater than Vmax ( S155 : NO), the laser control processor 130 advances the process to S156 .

[0340] In S156, the laser control processor 130 sets the repetition frequency f to the next value f+Δf. Δf is the amount of change in the repetition frequency f for calibration of the third relationship RY(f,V).

[0341] In S157, the laser control processor 130 determines whether the repetition frequency f is less than fmax.

[0342] When the repetition frequency f is smaller than fmax ( S157 : YES), the laser control processor 130 returns the process to S152 .

[0343] When the repetition frequency f is greater than or equal to fmax (S157: No), the laser control processor 130 ends the processing of this flowchart and returns to Fig.26 Processing shown.

[0344] Fig.28 An example of data stored in the memory 132 through the third relationship RY(f, V) calibration is shown. In the third relationship RY(f, V) calibration, the intensity ratio R calibration is performed multiple times according to the repetition frequency f and the charging voltage V (S16). As a result, a plurality of third relationships RY(f, V) corresponding to the repetition frequency f and the charging voltage V are stored in the memory 132. The memory 132 may also store a plurality of third relationships RY(f, V) in the form of a table. In the following description, this table is sometimes referred to as a "third relationship RY(f, V) table".

[0345] exist Fig.28 , the third relationship RY(fi, Vj) is the relationship between the intensity ratio R obtained by setting the i-th repetition frequency fi and the j-th charging voltage Vj and performing the intensity ratio R calibration and the position Y of the linear stage 612. The number of the third relationship RY(fi, Vj) is equivalent to the number obtained by multiplying the maximum value of i and the maximum value of j.

[0346] 3.3 Exposure Light Output

[0347] Fig.29 This is a flowchart showing the process of outputting exposure light in the second embodiment. Fig.29 The processing shown is equivalent to Fig.26 The S21b subroutine.

[0348] In S210 b , the laser control processor 130 sets the repetition frequency f and the charging voltage V according to the signal received from the exposure control processor 210 .

[0349] In S211b, the laser control processor 130 searches the third relationship RY(f, V) table using the set repetition frequency f and the charging voltage V. The laser control processor 130 determines the third relationship RY(f, V) corresponding to the set repetition frequency f and the charging voltage V.

[0350] For example, when the repetition frequency f set in S210b is greater than or equal to f1 and less than or equal to f2, and the charging voltage V set is greater than or equal to V1 and less than V2, Fig.28 The third relationship RY(f1,V1) is determined in the third relationship RY(f,V) table.

[0351] The processing after S212 is the same as the corresponding processing in the first embodiment. That is, the first rotating stage 512, the second rotating stage 522 and the linear stage 612 are controlled according to the third relationship RY(f1, V1) determined in S211b so that the wavelengths λ1, λ2 and the intensity ratio R are close to the target values. Then, the exposure light is output.

[0352] 3.4 Function

[0353] (7) According to the second embodiment, the third relationship RY(f, V) is associated with the repetition frequency f of the pulsed laser and is stored in the memory 132. The laser control processor 130 controls the linear stage 612 based on the third relationship RY(f, V) associated with the repetition frequency f of the pulsed laser and the position Y of the linear stage 612 measured by the encoder 613.

[0354] In the first and second embodiments, the light beam is spatially divided into the first part B1 and the second part B2 and the wavelengths are controlled separately. Therefore, it is preferable that the gas density is uniform in the optical path of the light beam. However, when the repetition frequency f changes, the gas density fluctuates in the optical path of the light beam, which sometimes affects the intensity ratio R. According to the second embodiment, an appropriate third relationship RY(f, V) is selected according to the repetition frequency f, so the accuracy of the control of the intensity ratio R can be improved.

[0355] (8) According to the second embodiment, the laser device 100 includes the laser cavity 10, the pair of electrodes 11a and 11b disposed in the laser cavity 10, and the charger 12 that holds electric energy for applying a voltage to the electrodes 11a and 11b.

[0356] The third relationship RY(f, V) is associated with the charging voltage V of the charger 12 and is stored in the memory 132. The laser control processor 130 controls the linear stage 612 based on the third relationship RY(f, V) associated with the charging voltage V of the charger 12 and the position Y of the linear stage 612 measured by the encoder 613.

[0357] In the first and second embodiments, when the charging voltage V changes, fluctuations in gas density occur in the optical path of the light beam, which may affect the intensity ratio R. According to the second embodiment, an appropriate third relationship RY(f, V) is selected according to the charging voltage V, so that the accuracy of controlling the intensity ratio R can be improved.

[0358] 3.5 Other structural examples

[0359] In the second embodiment, the case where the repetition frequency f and the charging voltage V are considered in the third relationship RY between the position Y of the linear stage 612 and the intensity ratio R and stored as a third relationship RY(f,V) table is described, but the present disclosure is not limited thereto. For example, the relationship between the position Y of the linear stage 612, the intensity ratio R, the repetition frequency f and the charging voltage V may be expressed by the following formula.

[0360] R=a1·Y+a2·Y 2 +b1·f+b2·f 2 +c1·V+c1·V 2 +d

[0361] Regarding other aspects, the second embodiment is the same as the first embodiment.

[0362] 4. Laser device that adjusts the intensity ratio R without using the third relationship RY

[0363] 4.1 Main Process

[0364] Fig.301 is a flowchart showing the operation of the laser control processor 130 in the third embodiment. The structure of the laser device 100 in the third embodiment is the same as that in the first embodiment. The third embodiment is different from the first embodiment in that the position Y of the linear stage 612 is set (S17c) instead of the intensity ratio R calibration (S16). In addition, in the third embodiment, the output of exposure light (S21c) is performed instead of the output of exposure light (S21). In addition, the processing of storing the positions of various actuators (S12) and returning the various actuators to the stored positions (S18) in the first embodiment are omitted in the third embodiment.

[0365] 4.2 Setting of the position Y of the linear stage 612

[0366] Fig.31 This is a flowchart showing the process of setting the position Y of the linear stage 612 in the third embodiment. Fig.31 The processing shown is equivalent to Fig.30 The S17c subroutine.

[0367] S170 and S171 processing and Fig.18 That is, the laser control processor 130 controls the first rotating stage 512 and the second rotating stage 522 so that the wavelength difference between the wavelength λ1 and the wavelength λ2 becomes half of the free spectrum range of the optical measuring device 17 .

[0368] In S172, the laser control processor 130 sets the repetition frequency f and the charging voltage V according to the signal received from the exposure control processor 210. After the repetition frequency f and the charging voltage V are set, the position Y of the linear stage 612 is set, thereby enabling the intensity ratio R to be adjusted with high accuracy.

[0369] In S173 , the laser control processor 130 reads in the target intensity ratio Rt. The target intensity ratio Rt may also be received from the exposure control processor 210 .

[0370] In S174, the laser control processor 130 sends an oscillation trigger signal to the switch 13a of the pulse power module 13 (refer to Figure 2 ) to make the laser device 100 oscillate laser. This process is similar to S133 (refer to Fig.16 )same.

[0371] In S175 , the laser control processor 130 measures the intensity ratio R using the light measuring device 17 .

[0372] In S176, the laser control processor 130 determines whether the difference between the intensity ratio R and the target intensity ratio Rt is within an allowable range.

[0373] If the difference between the intensity ratio R and the target intensity ratio Rt is within the permissible range (S176: Yes), the laser control processor 130 ends the processing of this flowchart and returns to Fig.30 Processing shown.

[0374] When the difference between the intensity ratio R and the target intensity ratio Rt is not within the permissible range ( S176 : No), the laser control processor 130 advances the process to S177 .

[0375] In S177, the laser control processor 130 controls the linear stage 612 so that the measured intensity ratio R approaches the target intensity ratio Rt.

[0376] After S177, the laser control processor 130 returns the process to S174.

[0377] 4.3 Exposure Light Output

[0378] Fig.32 This is a flowchart showing the process of outputting exposure light in the third embodiment. Fig.32 The processing shown is equivalent to Fig.30 The S21c subroutine.

[0379] Fig.32 The processing shown is similar to Fig.25 The processing of the first embodiment shown is different in that the control of the linear stage 612 based on the target intensity ratio Rt is not included. Fig.32 The processing shown is similar to Fig.25 The processing shown in FIG. 1 is the same as that shown in FIG. That is, the target position θ1t of the first rotating table 512 and the target position θ2t of the second rotating table 522 are calculated based on the first relationship λ1θ1 and the second relationship λ2θ2 (S213c). Furthermore, the first rotating table 512 and the second rotating table 522 are controlled so that the position θ1 of the first rotating table 512 measured by the encoder 513 and the position θ2 of the second rotating table 522 measured by the encoder 523 are close to the target positions θ1t and θ2t, respectively (S214c). Then, the exposure light is output.

[0380] 4.4 Function

[0381] (9) According to the third embodiment, the laser device 100 includes the linear stage 612 that changes the intensity ratio R between the wavelength λ1 and the wavelength λ2, and the optical measuring device 17 that measures the intensity ratio R between the wavelength λ1 and the wavelength λ2.

[0382] The laser control processor 130 reads the target intensity ratio Rt (S173), and controls the linear stage 612 so that the intensity ratio R measured by the light measuring device 17 approaches the target intensity ratio Rt (S177). Then, the laser control processor 130 controls the first rotating table 512 based on the first relationship λ1θ1 and the position θ1 of the first rotating table 512 measured by the encoder 513, and controls the second rotating table 522 based on the second relationship λ2θ2 and the position θ2 of the second rotating table 522 measured by the encoder 523 (S214c).

[0383] Thus, after the laser control processor 130 controls the linear stage 612 based on the measurement result of the intensity ratio R, it controls the first rotating stage 512 and the second rotating stage 522 based on the first relationship λ1θ1 and the second relationship λ2θ2 and the measurement results of the encoders 513 and 523. Therefore, even without measuring the third relationship RY in advance, the intensity ratio R can be adjusted, and when outputting the exposure light, the wavelength λ1 and the wavelength λ2 can be adjusted based on the first relationship λ1θ1 and the second relationship λ2θ2.

[0384] (10) According to the third embodiment, the laser control processor 130 controls the first rotating stage 512 and the second rotating stage 522 so that the wavelength difference between the wavelength λ1 and the wavelength λ2 approaches half of the free spectrum range of the optical measuring device 17 (S170, S171). Then, the laser control processor 130 controls the linear stage 612 so that the intensity ratio R measured by the optical measuring device 17 approaches the target intensity ratio Rt (S175, S177).

[0385] Thus, by adjusting the wavelength difference between the wavelength λ1 and the wavelength λ2 to be close to half of the free spectrum range, the wavelength λ1 and the wavelength λ2 can be output simultaneously, and the intensity ratio R thereof can be measured to control the linear stage 612. Then, when outputting exposure light, the first relationship λ1θ1 and the second relationship λ2θ2 are used, thereby adjusting the wavelength λ1 and the wavelength λ2 to the target wavelength λ1t and the target wavelength λ2t, respectively.

[0386] Regarding other aspects, the third embodiment is the same as the above-mentioned first embodiment.

[0387] 5. Arrange a plurality of prisms 43 and 44 in the XZ plane to form a narrow band device 14d

[0388] 5.1 Structure

[0389] Fig.33 and Fig.34 The structure of the bandwidth narrowing device 14d in the fourth embodiment is schematically shown. Fig.33 The narrowband device 14d is shown as viewed in the +Y direction. Fig.34The band narrowing device 14d viewed in the -X direction is shown. The band narrowing device 14d includes prisms 43 and 44, a grating 53, and a parallel plane substrate 71 instead of the grating system 50a and the beam splitting optical system 60a in the first embodiment.

[0390] The prisms 43 and 44 are arranged at different positions in the wavelength dispersion direction DD of either prism 43 or 44 in the optical path of the light beam after passing through the prism 42. The prism 43 is supported by a holder 431, and the prism 44 is supported by a holder 441. The positions of the prisms 43 and 44 are set so that the light beam after passing through the prism 42 crosses the prisms 43 and 44 and enters the prisms 43 and 44. The wavelength dispersion direction DD of the prism refers to the direction in which the refraction angle of light at the surface of the prism is dispersed according to the wavelength. Fig.33 and Fig.34 In the example shown, the wavelength dispersion directions DD of the prisms 43 and 44 are the same.

[0391] The prisms 43 and 44 are arranged so that the surfaces of the prisms 43 and 44 through which the light beams are incident and emitted are parallel to the Y-axis.

[0392] The prism 43 can be rotated around an axis parallel to the Y axis by the third rotating table 432 , and the prism 44 can be rotated around an axis parallel to the Y axis by the fourth rotating table 442 .

[0393] An encoder 433 is attached to the third rotating table 432 of the prism 43 . An encoder 443 is attached to the fourth rotating table 442 of the prism 44 .

[0394] In the fourth embodiment, the prism 43 is equivalent to the first optical element in the present disclosure, and the prism 44 is equivalent to the second optical element in the present disclosure. The third rotating table 432 is equivalent to the first actuator in the present disclosure, and the fourth rotating table 442 is equivalent to the second actuator in the present disclosure. The encoder 433 is equivalent to the first encoder in the present disclosure, and the encoder 443 is equivalent to the second encoder in the present disclosure.

[0395] The grating 53 is arranged to straddle the optical paths of the first portion B1 of the light beam after passing through the prism 43 and the second portion B2 of the light beam after passing through the prism 44 . The direction of the grooves of the grating 53 coincides with the Y-axis direction. The grating 53 is supported by a holder 531 .

[0396] The parallel plane substrate 71 is arranged on the optical path of the light beam emitted from the window 10a. For example, the parallel plane substrate 71 is arranged on the optical path of the light beam between the window 10a and the prism 41. The parallel plane substrate 71 is supported by a holder 711. The parallel plane substrate 71 is arranged so that the surfaces of the parallel plane substrate 71 for the light beam to be incident and emitted are all parallel to the Y axis. The parallel plane substrate 71 is configured to be rotatable around an axis parallel to the Y axis by the fifth rotating table 712. An encoder 713 is installed on the fifth rotating table 712 of the parallel plane substrate 71.

[0397] The fifth rotating table 712 in the fourth embodiment corresponds to the third actuator in the present disclosure. The encoder 713 corresponds to the third encoder in the present disclosure.

[0398] 5.2 Action

[0399] The parallel plane substrate 71 refracts the light beam in opposite directions at the same angle at the surface where the light beam emitted from the window 10a is incident and the surface where the light beam is emitted toward the prism 41, so that the light beam is transmitted. Therefore, the traveling direction of the light beam emitted from the parallel plane substrate 71 is the same as the traveling direction of the light beam incident on the parallel plane substrate 71, and the optical path axis is displaced in the X-axis direction according to the posture of the parallel plane substrate 71. The optical path axis refers to the central axis of the optical path.

[0400] The light beam transmitted through the parallel plane substrate 71 enters the prism 41 and then enters the prism 42. The prisms 41 and 42 expand the beam width of the light beam in a plane parallel to the XZ plane and transmit the light beam.

[0401] The first part B1 of the light beam after passing through the prism 42 is incident on the prism 43, and the second part B2 is incident on the prism 44. The incident angles of the light beams incident on the prisms 43 and 44 depend on the postures of the prisms 43 and 44. The light beams incident on the prisms 43 and 44 change their traveling directions according to the postures of the prisms 43 and 44, and are emitted toward the grating 53.

[0402] The light incident on the grating 53 from the prisms 43 and 44 is reflected by the plurality of grooves of the grating 53, and diffracted in a direction corresponding to the wavelength of the light. Thus, the light reflected by the plurality of grooves of the grating 53 is dispersed in a plane parallel to the XZ plane. The prism 43 is arranged in a posture in which the incident angle of the first part B1 of the light beam incident on the grating 53 from the prism 43 and the diffraction angle of the light of wavelength λ1 in the diffracted light diffracted by the grating 53 coincide with each other. The prism 44 is arranged in a posture in which the incident angle of the second part B2 of the light beam incident on the grating 53 from the prism 44 and the diffraction angle of the light of wavelength λ2 in the diffracted light diffracted by the grating 53 coincide with each other. In the case where the incident angles of the light beams incident on the grating 53 from the prisms 43 and 44 are different from each other, a wavelength difference is generated between the wavelength λ1 of the diffracted light returning from the grating 53 to the prism 43 and the wavelength λ2 of the diffracted light returning from the grating 53 to the prism 44.

[0403] exist Fig.33 and Fig.34 In FIG. 1 , the dotted arrows representing the light beams only show the direction from the prism 41 toward the grating 53, but the light beam of the selected wavelength of the narrowband device 14d travels from the grating 53 toward the prism 41 in the opposite path to these dotted arrows.

[0404] The prisms 41 to 44 reduce the beam width of the light returning from the grating 53 in a plane parallel to the XZ plane, and return the light to the laser cavity 10 through the window 10 a.

[0405] The third rotating stage 432 and the fourth rotating stage 442 are controlled by the laser control processor 130 .

[0406] When the third rotating stage 432 slightly rotates the prism 43, the traveling direction of the first part B1 of the light beam emitted from the prism 43 toward the grating 53 slightly changes in a plane parallel to the XZ plane. As a result, the incident angle of the first part B1 of the light beam incident on the grating 53 from the prism 43 slightly changes. As a result, the wavelength λ1 changes.

[0407] When the fourth rotating stage 442 slightly rotates the prism 44, the traveling direction of the second portion B2 of the light beam emitted from the prism 44 toward the grating 53 slightly changes in a plane parallel to the XZ plane. As a result, the incident angle of the second portion B2 of the light beam incident on the grating 53 from the prism 44 slightly changes. As a result, the wavelength λ2 changes.

[0408] Through the above structure and operation, the wavelength λ1 and the wavelength λ2 of the light beam emitted from the window 10a of the laser cavity 10 are selected and returned to the laser cavity 10. Thus, the laser device 100 can perform dual-wavelength oscillation. By controlling the third rotating stage 432 and the fourth rotating stage 442, the wavelength λ1 and the wavelength λ2 can also be set separately.

[0409] The fifth rotating stage 712 changes the posture of the parallel plane substrate 71, thereby changing the displacement amount of the light beam in the X-axis direction when passing through the parallel plane substrate 71, and the position of the light beam incident on the prisms 41 to 44 changes in the X-axis direction. As a result, the ratio of the first part B1 to the second part B2 changes. For example, when the parallel plane substrate 71 is rotated in the same direction as the parallel plane substrate 71, the displacement amount of the light beam in the X-axis direction changes. Fig.33 When the parallel plane substrate 71 is rotated in the clockwise direction, the proportion of the first part B1 decreases, and when the parallel plane substrate 71 is rotated in the counterclockwise direction, the proportion of the first part B1 increases. Thus, the intensity ratio R of the wavelength component of wavelength λ1 and the wavelength component of wavelength λ2 contained in the pulsed laser can be adjusted.

[0410] The laser control processor 130 controls the third rotating stage 432 based on the target wavelength λ1t received from the exposure control processor 210. Thus, the third rotating stage 432 changes the posture of the prism 43.

[0411] The laser control processor 130 controls the fourth rotating stage 442 based on the target wavelength λ2t received from the exposure control processor 210. Thus, the fourth rotating stage 442 changes the posture of the prism 44.

[0412] The laser control processor 130 controls the fifth rotating stage 712 according to the target intensity ratio Rt received from the exposure control processor 210 . Thus, the fifth rotating stage 712 adjusts the posture of the parallel plane substrate 71 .

[0413] In other respects, the fourth embodiment is the same as any one of the first to third embodiments. However, in the flowcharts of the first to third embodiments, the components of the first embodiment are replaced by the corresponding components of the fourth embodiment. For example, the first rotating table 512, the second rotating table 522, and the linear table 612 in the first embodiment are replaced by the third rotating table 432, the fourth rotating table 442, and the fifth rotating table 712 in the fourth embodiment.

[0414] 5.3 First Modification

[0415] Fig.35 and Fig.36 The structure of the bandwidth narrowing device 14e in the first modified example of the fourth embodiment is schematically shown. Fig.35 The narrowband device 14e is shown as viewed in the +Y direction. Fig.36 The band-narrowing device 14e is shown as viewed in the -X direction.

[0416] In the narrow-band device 14e, the prism 42 can be rotated around an axis parallel to the Y axis by a sixth rotating table 422. An encoder 423 is attached to the sixth rotating table 422 of the prism 42.

[0417] The prism 42 in the first modification example corresponds to the first optical element in the present disclosure. The sixth rotating table 422 corresponds to the first actuator in the present disclosure. The encoder 423 corresponds to the first encoder in the present disclosure.

[0418] In the band narrowing device 14 e , the prism 43 is supported by a holder 431 so as to maintain a constant posture.

[0419] In the first variant, the sixth rotating stage 422 rotates the prism 42. As a result, the incident angle of the light beam incident from the prism 42 to the grating 53 via the prisms 43 and 44 changes. As a result, both the wavelength λ1 and the wavelength λ2 change. In addition, by rotating the prism 44 by the fourth rotating stage 442, the wavelength λ2 can be changed independently of the wavelength λ1, and the wavelength difference between the wavelength λ1 and the wavelength λ2 can be changed. Therefore, by controlling both the sixth rotating stage 422 and the fourth rotating stage 442, the wavelength λ1 and the wavelength λ2 can be made close to the target wavelengths λ1t and λ2t, respectively.

[0420] When the prism 42 is rotated, the incident position of the light beam from the prism 42 toward the prisms 43 and 44 also changes. Therefore, when the prism 42 is rotated, the ratio of the first part B1 to the second part B2 changes, and the intensity ratio R of the wavelength λ1 to the wavelength λ2 changes. When the intensity ratio R of the wavelength λ1 to the wavelength λ2 is out of the allowable range due to the rotation of the prism 42, the intensity ratio R of the wavelength λ1 to the wavelength λ2 can also be adjusted by controlling the posture of the parallel plane substrate 71.

[0421] Regarding other aspects, the first variant is similar to the reference Fig.33 and Fig.34 However, in each flowchart, the third rotating table 432 of the fourth embodiment is replaced by the sixth rotating table 422 of the first modified example.

[0422] 5.4 Second Modification

[0423] Fig.37 and Fig.38 The structure of a bandwidth narrowing device 14f in a second modified example of the fourth embodiment is schematically shown. Fig.37 The narrowband device 14f is shown as viewed in the +Y direction. Fig.38 The band-narrowing device 14f is shown as viewed in the -X direction.

[0424] The narrowband device 14f includes a linear stage 452. An encoder 453 is mounted on the linear stage 452.

[0425] The linear stage 452 is configured to move the prisms 43 and 44 together with their respective holders 431 and 441, the third and fourth rotating stages 432 and 442, and the encoders 433 and 443. The moving direction of the prisms 43 and 44 realized by the linear stage 452 is a direction intersecting the YZ plane. The direction intersecting the YZ plane is a direction intersecting a plane parallel to both the optical path axis of the light beam incident from the prism 42 to the prisms 43 and 44 and the grooves of the grating 53, for example, the wavelength dispersion direction DD of either prism 43 or 44 (see Fig.33 ).

[0426] In the second modification, the linear stage 452 is equivalent to the third actuator in the present disclosure. The encoder 453 is equivalent to the third encoder in the present disclosure. In the second modification, the parallel plane substrate 71 (see Fig.33 and Fig.34 ).

[0427] When the linear stage 452 moves the prisms 43 and 44, the ratio of the first part B1 incident on the prism 43 and the second part B2 incident on the prism 44 in the light beam emitted from the prism 42 changes. For example, when the prisms 43 and 44 are moved in the -H direction, the ratio of the first part B1 decreases, and when the prisms 43 and 44 are moved in the +H direction, the ratio of the first part B1 increases.

[0428] Regarding other aspects, the second variant is similar to the reference Fig.33 and Fig.34 The fourth embodiment described above is the same as that described above, but the fifth rotating table 712 of the fourth embodiment is replaced by the linear table 452 of the second modified example.

[0429] 6. Others

[0430] The above description is not limiting but simply illustrative. Therefore, those skilled in the art will appreciate that changes can be made to the embodiments of the present disclosure without departing from the claims. In addition, those skilled in the art will appreciate that the embodiments of the present disclosure can be used in combination.

[0431] Unless explicitly stated otherwise, the terms used in this specification and claims as a whole should be interpreted as "non-limiting" terms. For example, terms such as "including" or "comprising" should be interpreted as "not limited to the parts recorded as included". Terms such as "having" should be interpreted as "not limited to the parts recorded as having". In addition, the indefinite article "one" should be interpreted as meaning "at least one" or "one or more". In addition, terms such as "at least one of A, B and C" should be interpreted as "A", "B", "C", "A+B", "A+C", "B+C" or "A+B+C". Furthermore, it should be interpreted as also including combinations of them and parts other than "A", "B" and "C".

Claims

1. A laser device, comprising: a first optical element and a second optical element; a first actuator that changes the posture of the first optical element, thereby changing the first wavelength component included in the pulsed laser light; a second actuator that changes the posture of the second optical element, thereby changing the second wavelength component included in the pulsed laser light; a first encoder for measuring a position of the first actuator; a second encoder for measuring a position of the second actuator; an optical measuring device for measuring the first wavelength component and the second wavelength component; a third actuator that changes the intensity ratio between the first wavelength component and the second wavelength component; and processor, the processor measures the first wavelength component using the optical measuring device in a state where the ratio of the first wavelength component is made larger than the ratio of the second wavelength component by the third actuator, The processor stores the relationship between the position of the first actuator measured by the first encoder and the first wavelength component as a first relationship in a storage device, the processor measures the second wavelength component using the optical measuring device in a state where the proportion of the second wavelength component is made larger than the proportion of the first wavelength component by the third actuator, the processor stores the relationship between the position of the second actuator measured by the second encoder and the second wavelength component in the storage device as a second relationship, the processor reads the first relationship and the second relationship, The processor controls the first actuator based on the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator based on the second relationship and the position of the second actuator measured by the second encoder.

2. The laser device according to claim 1, wherein: The laser device also has: a third encoder for measuring the position of the third actuator, the processor reads a third relationship between the position of the third actuator and the intensity ratio, The processor controls the third actuator based on the third relationship and the position of the third actuator measured by the third encoder.

3. The laser device according to claim 2, wherein: The light measuring device further measures the intensity ratio between the first wavelength component and the second wavelength component. The processor measures the intensity ratio using the light measuring device, and stores the relationship between the position of the third actuator measured by the third encoder and the intensity ratio in the storage device as the third relationship.

4. The laser device according to claim 3, wherein: The processor controls the first actuator and the second actuator so that the wavelength difference between the first wavelength component and the second wavelength component approaches half of the free spectral range of the optical measuring device. Then, the processor measures the intensity ratio using the light measuring device.

5. The laser device according to claim 2, wherein: The third relationship is stored in the storage device in association with the repetition frequency of the pulse laser. The processor controls the third actuator based on the third relationship associated with the repetition frequency of the pulsed laser and the position of the third actuator measured by the third encoder.

6. The laser device according to claim 2, wherein: The laser device also has: Laser cavity; a pair of electrodes disposed in the laser cavity; and a charger that maintains electrical energy for applying a voltage to the electrodes, The third relationship is stored in the storage device in association with the charging voltage of the charger, The processor controls the third actuator based on the third relationship associated with the charging voltage of the charger and the position of the third actuator measured by the third encoder.

7. The laser device according to claim 1, wherein: The light measuring device further measures the intensity ratio between the first wavelength component and the second wavelength component. The processor reads in the target intensity ratio, the processor controls the third actuator so that the intensity ratio measured by the light measuring device approaches the target intensity ratio, Then, the processor controls the first actuator based on the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator based on the second relationship and the position of the second actuator measured by the second encoder.

8. The laser device according to claim 7, wherein: The processor controls the first actuator and the second actuator so that the wavelength difference between the first wavelength component and the second wavelength component approaches half of the free spectral range of the optical measuring device. Then, the processor controls the third actuator so that the intensity ratio measured by the light measuring device approaches the target intensity ratio.

9. A wavelength control method, which is a wavelength control method for a laser device, wherein the laser device has: a first optical element and a second optical element; a first actuator that changes the posture of the first optical element, thereby changing the first wavelength component included in the pulsed laser light; a second actuator that changes the posture of the second optical element, thereby changing the second wavelength component included in the pulsed laser light; a first encoder for measuring a position of the first actuator; a second encoder for measuring a position of the second actuator; an optical measuring device for measuring the first wavelength component and the second wavelength component; a third actuator that changes the intensity ratio between the first wavelength component and the second wavelength component; and processor, the processor measures the first wavelength component using the optical measuring device in a state where the ratio of the first wavelength component is made larger than the ratio of the second wavelength component by the third actuator, The processor stores the relationship between the position of the first actuator measured by the first encoder and the first wavelength component as a first relationship in a storage device, the processor measures the second wavelength component using the optical measuring device in a state where the proportion of the second wavelength component is made larger than the proportion of the first wavelength component by the third actuator, the processor stores the relationship between the position of the second actuator measured by the second encoder and the second wavelength component in the storage device as a second relationship, the processor reads the first relationship and the second relationship, The processor controls the first actuator based on the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator based on the second relationship and the position of the second actuator measured by the second encoder.

10. The wavelength control method according to claim 9, wherein: The laser device also has: a third encoder for measuring the position of the third actuator, the processor reads a third relationship between the position of the third actuator and the intensity ratio, The processor controls the third actuator based on the third relationship and the position of the third actuator measured by the third encoder.

11. The wavelength control method according to claim 10, wherein: The light measuring device further measures the intensity ratio between the first wavelength component and the second wavelength component. The processor measures the intensity ratio using the light measuring device, and stores the relationship between the position of the third actuator measured by the third encoder and the intensity ratio in the storage device as the third relationship.

12. The wavelength control method according to claim 11, wherein: The processor controls the first actuator and the second actuator so that the wavelength difference between the first wavelength component and the second wavelength component approaches half of the free spectral range of the optical measuring device. Then, the processor measures the intensity ratio using the light measuring device.

13. The wavelength control method according to claim 10, wherein: The third relationship is stored in the storage device in association with the repetition frequency of the pulsed laser. The processor controls the third actuator based on the third relationship associated with the repetition frequency of the pulsed laser and the position of the third actuator measured by the third encoder.

14. The wavelength control method according to claim 10, wherein: The laser device also has: Laser cavity; a pair of electrodes disposed in the laser cavity; and a charger that maintains electrical energy for applying a voltage to the electrodes, The third relationship is stored in the storage device in association with the charging voltage of the charger, The processor controls the third actuator based on the third relationship associated with the charging voltage of the charger and the position of the third actuator measured by the third encoder.

15. The wavelength control method according to claim 9, wherein: The light measuring device further measures the intensity ratio between the first wavelength component and the second wavelength component. The processor reads in the target intensity ratio, the processor controls the third actuator so that the intensity ratio measured by the light measuring device approaches the target intensity ratio, Then, the processor controls the first actuator based on the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator based on the second relationship and the position of the second actuator measured by the second encoder.

16. A method for manufacturing an electronic device, comprising the following steps: Generate pulsed laser light through a laser device, outputting the pulse laser to an exposure device, exposing the pulsed laser on a photosensitive substrate in the exposure device to manufacture an electronic device, The laser device has: a first optical element and a second optical element; a first actuator that changes the posture of the first optical element, thereby changing the first wavelength component included in the pulsed laser light; a second actuator that changes the posture of the second optical element, thereby changing the second wavelength component included in the pulsed laser light; a first encoder for measuring a position of the first actuator; a second encoder for measuring a position of the second actuator; an optical measuring device for measuring the first wavelength component and the second wavelength component; a third actuator that changes the intensity ratio between the first wavelength component and the second wavelength component; and processor, the processor measures the first wavelength component using the optical measuring device in a state where the ratio of the first wavelength component is made larger than the ratio of the second wavelength component by the third actuator, The processor stores the relationship between the position of the first actuator measured by the first encoder and the first wavelength component as a first relationship in a storage device, the processor measures the second wavelength component using the optical measuring device in a state where the proportion of the second wavelength component is made larger than the proportion of the first wavelength component by the third actuator, the processor stores the relationship between the position of the second actuator measured by the second encoder and the second wavelength component in the storage device as a second relationship, the processor reads the first relationship and the second relationship, The processor controls the first actuator based on the first relationship and the position of the first actuator measured by the first encoder, and controls the second actuator based on the second relationship and the position of the second actuator measured by the second encoder.

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