Narrowband gas laser device, its control method, and method for manufacturing an electronic device

Abstract

A control method for a narrowband gas laser device, the narrowband gas laser device outputs pulsed laser containing a first wavelength component and a second wavelength component. Among them, the narrowband gas laser device has: a laser cavity, which includes a pair of electrodes; an optical resonator, which includes an adjustment mechanism, and the adjustment mechanism adjusts a parameter of the energy ratio between the first wavelength component and the second wavelength component; and a processor, which stores relationship data, and the relationship data represents the relationship between the parameter of the energy ratio and the control parameter of the adjustment mechanism. The control method includes the following steps: receiving an instruction value of the parameter of the energy ratio from an external device; and obtaining the value of the control parameter corresponding to the instruction value according to the relationship data, and controlling the adjustment mechanism according to the value of the control parameter.

Description

Technical Field

[0001] The present invention relates to a narrowband gas laser device, a control method thereof, and a manufacturing method of an electronic device. Background Art

[0002] In recent years, in semiconductor exposure devices, with the miniaturization and high integration of semiconductor integrated circuits, an improvement in resolution has been required. Therefore, the shortening of the wavelength of light emitted from an exposure light source has been developed. For example, as a gas laser device for exposure, a KrF excimer laser device that emits laser light with an output wavelength of approximately 248 nm, and an ArF excimer laser device that emits laser light with an output wavelength of approximately 193 nm are used.

[0003] The spectral line width of the spontaneous oscillation light of a KrF excimer laser device and an ArF excimer laser device is relatively wide, approximately 350 to 400 pm. Therefore, when a projection lens is formed of a material that transmits ultraviolet rays such as KrF and ArF lasers, chromatic aberration may occur. As a result, the resolution may be reduced. Therefore, it is necessary to narrow the spectral line width of the laser output from the gas laser device to a level where chromatic aberration can be ignored. Therefore, in the laser resonator of the gas laser device, in order to narrow the spectral line width, a narrowing module (Line Narrowing Module: LNM) including a narrowing element (etalon, grating, etc.) may be provided. Hereinafter, a gas laser device whose spectral line width has been narrowed will be referred to as a narrowband gas laser device.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: US Patent No. 7088758 Specification

[0007] Patent Document 2: US Patent No. 7154928 Specification

[0008] Patent Document 3: International Publication No. 2019 / 079010

[0009] Patent Document 4: Japanese Unexamined Patent Application Publication No. 2006 - 269628 Summary of the Invention

[0010] One aspect of the control method of the present invention is a control method for a narrowband gas laser device that outputs pulsed laser light containing a first wavelength component and a second wavelength component. The narrowband gas laser device includes: a laser cavity that includes a pair of electrodes; an optical resonator that includes an adjustment mechanism for adjusting a parameter of the energy ratio between the first wavelength component and the second wavelength component; and a processor that stores relationship data representing the relationship between the parameter of the energy ratio and the control parameter of the adjustment mechanism. The control method includes the steps of: receiving a command value of the parameter of the energy ratio from an external device; and obtaining a value of the control parameter corresponding to the command value based on the relationship data, and controlling the adjustment mechanism according to the value of the control parameter.

[0011] One aspect of the narrowband gas laser device of the present invention outputs pulsed laser light containing a first wavelength component and a second wavelength component. The narrowband gas laser device includes: a laser cavity that includes a pair of electrodes; an optical resonator that includes an adjustment mechanism for adjusting a parameter of the energy ratio between the first wavelength component and the second wavelength component; and a processor that stores relationship data representing the relationship between the parameter of the energy ratio and the control parameter of the adjustment mechanism. The processor receives a command value of the parameter of the energy ratio from an external device, obtains a value of the control parameter corresponding to the command value based on the relationship data, and controls the adjustment mechanism according to the value of the control parameter.

[0012] One aspect of the manufacturing method of an electronic device of the present invention includes the steps of: generating pulsed laser light using a narrowband gas laser device; outputting the pulsed laser light to an exposure device; and exposing the pulsed laser light on a photosensitive substrate in the exposure device to manufacture an electronic device. The narrowband gas laser device outputs pulsed laser light containing a first wavelength component and a second wavelength component. The narrowband gas laser device includes: a laser cavity that includes a pair of electrodes; an optical resonator that includes an adjustment mechanism for adjusting a parameter of the energy ratio between the first wavelength component and the second wavelength component; and a processor that stores relationship data representing the relationship between the parameter of the energy ratio and the control parameter of the adjustment mechanism. The processor receives a command value of the parameter of the energy ratio from an external device, obtains a value of the control parameter corresponding to the command value based on the relationship data, and controls the adjustment mechanism according to the value of the control parameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Hereinafter, several embodiments of the present invention will be described as simple examples with reference to the drawings.

[0014] Figure 1 Schematically shows the structure of the exposure system in the comparative example.

[0015] Figure 2 Schematically shows the structure of the exposure system in the comparative example.

[0016] Figure 3A Schematically shows the structure of the narrowbanding device in the comparative example.

[0017] Figure 3B Schematically shows the structure of the narrowbanding device in the comparative example.

[0018] Figure 4A Schematically shows the structure of the narrowbanding device in the first embodiment.

[0019] Figure 4B Schematically shows the structure of the narrowbanding device in the first embodiment.

[0020] Figure 5 Is a flowchart showing the processing procedure of two-wavelength oscillation in the first embodiment.

[0021] Figure 6 Is a flowchart showing the processing procedure of wavelength control for two-wavelength oscillation.

[0022] Figure 7 Is a flowchart showing the processing procedure of energy control for two-wavelength oscillation.

[0023] Figure 8 Conceptually shows the table data stored in the memory.

[0024] Figure 9 Is a graph illustrating the relationship between the control parameter Y of the linear stage and the energy ratio R.

[0025] Figure 10 Is a flowchart showing the processing procedure of energy control for two-wavelength oscillation in the second embodiment.

[0026] Figure 11A Conceptually shows the table data stored in the memory.

[0027] Figure 11B Conceptually shows the table data stored in the memory.

[0028] Figure 12A Is a graph illustrating the relationship between the control parameter Y of the linear stage and the energy ratio R.

[0029] Figure 12B Is another graph illustrating the relationship between the control parameter Y of the linear stage and the energy ratio R. Detailed Description

[0030] Content

[0031] 1. Comparative Example

[0032] 1.1 Exposure System

[0033] 1.1.1 Structure of the exposure device 100

[0034] 1.1.2 Operation

[0035] 1.2 Narrowband gas laser device

[0036] 1.2.1 Structure

[0037] 1.2.1.1 Master oscillator MO

[0038] 1.2.1.2 Laser control processor 30

[0039] 1.2.1.3 Gas adjustment device GA

[0040] 1.2.2 Operation

[0041] 1.2.2.1 Laser control processor 30

[0042] 1.2.2.2 Master oscillator MO

[0043] 1.2.2.3 Gas adjustment device GA

[0044] 1.3 Narrowband device

[0045] 1.3.1 Structure

[0046] 1.3.1.1 First and second prisms 41 and 42

[0047] 1.3.1.2 Grating system 50

[0048] 1.3.2 Operation

[0049] 1.3.3 Problems of the comparative example

[0050] 2. Narrowband gas laser device that adjusts the energy ratio R with reference to table data

[0051] 2.1 Structure

[0052] 2.2 Operation of the narrowband gas laser device

[0053] 2.3 Control of two-wavelength oscillation performed by the laser control processor 30

[0054] 2.3.1 Wavelength control of two-wavelength oscillation

[0055] 2.3.2 Energy control of two-wavelength oscillation

[0056] 2.4 Function

[0057] 3. Narrowband gas laser device that adjusts the energy ratio R considering the charging voltage HV and the gas pressure P

[0058] 3.1 Structure and Operation

[0059] 3.2 Function

[0060] 4. Others

[0061] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below show several examples of the present invention and are not intended to limit the content of the present invention. In addition, the structures and operations described in each embodiment are not necessarily all essential to the structures and operations of the present invention. In addition, the same reference numerals are assigned to the same structural elements and repeated descriptions are omitted.

[0062] 1. Comparative Example

[0063] 1.1 Exposure System

[0064] Figure 1 and Figure 2 Schematically shows the structure of the exposure system in the comparative example. The comparative example of the present disclosure is a manner known only to the applicant and is not a publicly known example admitted by the applicant himself.

[0065] The exposure system includes a narrowband gas laser device 1 and an exposure device 100. In Figure 1 shows the narrowband gas laser device 1 schematically. In Figure 2 shows the exposure device 100 schematically.

[0066] The narrowband gas laser device 1 includes a laser control processor 30. The narrowband gas laser device 1 is configured to output pulsed laser light to the exposure device 100.

[0067] 1.1.1 Structure of Exposure Device 100

[0068] As Figure 1 shown, the exposure device 100 includes an illumination optical system 101, a projection optical system 102, and an exposure control processor 110. The exposure device 100 corresponds to an external device in the present invention.

[0069] The illumination optical system 101 illuminates a reticle pattern of an unillustrated reticle disposed on a reticle stage RT with pulsed laser light incident from the narrowband gas laser device 1.

[0070] The projection optical system 102 reduces and projects the pulsed laser light transmitted through the reticle and forms an image on an unillustrated workpiece disposed on a workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with a resist film.

[0071] The exposure control processor 110 is a processing device including a memory 112 storing a control program and a CPU (central processing unit) 111 that executes the control program. The exposure control processor 110 is particularly configured or programmed to perform various processes included in the present invention. The exposure control processor 110 overall controls the control of the exposure apparatus 100, and transmits and receives various data and various signals to and from the laser control processor 30.

[0072] 1.1.2 Operation

[0073] The exposure control processor 110 transmits data of the target value of the wavelength, data of the target value of the pulse energy, and a trigger signal to the laser control processor 30. The laser control processor 30 controls the narrowband gas laser device 1 in accordance with these data and signals.

[0074] The exposure control processor 110 causes the reticle stage RT and the workpiece stage WT to synchronously move parallel to each other in opposite directions. Thereby, the workpiece is exposed with pulsed laser light reflecting the reticle pattern.

[0075] Through such an exposure process, the reticle pattern is transferred onto the semiconductor wafer. Then, electronic devices can be manufactured through multiple processes.

[0076] 1.2 Narrowband Gas Laser Device

[0077] 1.2.1 Structure

[0078] As Figure 2 shown, the narrowband gas laser device 1 includes, in addition to the laser control processor 30, a master oscillator MO and a gas adjustment device GA.

[0079] 1.2.1.1 Master Oscillator MO

[0080] The master oscillator MO includes a laser cavity 10, a charger 12, a pulse power module (PPM) 13, a narrowbanding device 14, an output coupling mirror 15, a photodetector 17, and a shutter 18. The narrowbanding device 14 and the output coupling mirror 15 constitute an optical resonator.

[0081] The laser cavity 10 is disposed on the optical path of the optical resonator. Windows 10a and 10b are provided in the laser cavity 10.

[0082] The laser cavity 10 has a pair of electrodes 11a and 11b inside, and further houses a laser gas as a laser medium. The laser medium is, for example, F 2 , ArF, KrF, XeCl, or XeF.

[0083] A pressure sensor 16 is installed in the laser cavity 10.

[0084] The charger 12 holds the electric energy supplied to the pulse power module 13. The pulse power module 13 includes a switch 13a.

[0085] The narrowbanding device 14 includes wavelength selection elements such as the first and second prisms 41 and 42, and gratings 51 and 52 described later.

[0086] The output coupling mirror 15 is composed of a partial mirror.

[0087] The optical detector 17 includes a beam splitter 17a and a sensor unit 17b. The beam splitter 17a is disposed on the optical path of the pulsed laser output from the output coupling mirror 15. The beam splitter 17a is configured to transmit a part of the pulsed laser with a high transmittance and reflect another part of the pulsed laser to be incident on the sensor unit 17b. The sensor unit 17b is configured to include a spectroscopic sensor and be capable of outputting measurement data of the wavelength. Further, the sensor unit 17b is configured to include an energy sensor and be capable of outputting measurement data of the pulse energy.

[0088] The shutter 18 is disposed on the optical path of the pulsed laser that has passed through the beam splitter 17a. When the shutter 18 is closed, the pulsed laser that has passed through the beam splitter 17a is blocked and not incident on the exposure device 100. When the shutter 18 is open, the pulsed laser that has passed through the beam splitter 17a is not blocked and is incident on the exposure device 100.

[0089] 1.2.1.2 Laser control processor 30

[0090] The laser control processor 30 is a processing device that includes a memory 32 storing a control program and a CPU 31 executing the control program. The laser control processor 30 is specifically configured or programmed to execute various processes included in the present invention.

[0091] 1.2.1.3 Gas adjustment device GA

[0092] The gas adjustment device GA includes a gas supply device 33, a gas exhaust device 34, and a gas control processor 35.

[0093] The gas supply device 33 includes a valve (not shown) provided in the first pipe between the laser cavity 10 and a gas cylinder (not shown).

[0094] The gas exhaust device 34 includes a valve (not shown), a pump, and a decontamination device provided in the second pipe connected to the laser cavity 10.

[0095] The gas control processor 35 is a processing device that includes a memory 37 storing a control program and a CPU 36 executing the control program. The gas control processor 35 is specifically configured or programmed to execute various processes included in the present disclosure.

[0096] 1.2.2 Operations

[0097] 1.2.2.1 Laser control processor 30

[0098] The laser control processor 30 obtains data on the target value of the wavelength from the exposure control processor 110. The laser control processor 30 sends an initial setting signal to the narrowbanding device 14 based on the target value of the wavelength. After the output of the pulsed laser starts, the laser control processor 30 receives the measured data of the wavelength from the optical detector 17, and sends a feedback control signal to the narrowbanding device 14 based on the target value of the wavelength and the measured data of the wavelength.

[0099] The laser control processor 30 obtains data on the target value of the pulse energy from the exposure control processor 110. The laser control processor 30 sends an initial setting signal of the charging voltage to the charger 12 based on the target value of the pulse energy. After the output of the pulsed laser starts, the laser control processor 30 receives the measured data of the pulse energy from the optical detector 17, and sends a feedback control signal of the charging voltage to the charger 12 based on the target value of the pulse energy and the measured data of the pulse energy.

[0100] The laser control processor 30 receives a trigger signal from the exposure control processor 110. The laser control processor 30 sends an oscillation trigger signal based on the trigger signal to the switch 13a of the pulse power module 13.

[0101] The laser control processor 30 sends a gas control signal to the gas control processor 35. In addition, the laser control processor 30 receives the measured data of the air pressure P from the pressure sensor 16, and sends the measured data of the air pressure P to the gas control processor 35.

[0102] 1.2.2.2 Master oscillator MO

[0103] The switch 13a becomes in the on state after receiving the oscillation trigger signal from the laser control processor 30. After the switch 13a becomes in the on state, the pulse power module 13 generates a pulsed high voltage based on the electric energy held in the charger 12. The pulse power module 13 applies this high voltage to the electrodes 11a and 11b.

[0104] After applying the high voltage to the electrodes 11a and 11b, a discharge is caused between the electrodes 11a and 11b. By the energy of this discharge, the laser gas in the laser cavity 10 is excited and transitions to a high energy level. Then, when the excited laser gas transitions to a low energy level, it emits light with a wavelength corresponding to the energy level difference.

[0105] The light generated within the laser cavity 10 exits to the outside of the laser cavity 10 via windows 10a and 10b. The light exiting from window 10a enters the narrowbanding device 14 as a light beam. The light near the desired wavelength among the light incident on the narrowbanding device 14 is reflected back to the laser cavity 10 by the narrowbanding device 14.

[0106] The output coupling mirror 15 allows a part of the light exiting from window 10b to pass through and be output, and reflects the other part back to the laser cavity 10.

[0107] In this way, the light exiting from the laser cavity 10 reciprocates between the narrowbanding device 14 and the output coupling mirror 15. This light is amplified each time it passes through the discharge space between the pair of electrodes 11a and 11b. Laser oscillation is thus performed, and the light that has been narrowbanded is output as pulsed laser light from the output coupling mirror 15.

[0108] The pulsed laser light output from the narrowbanded gas laser device 1 is incident on the exposure device 100.

[0109] 1.2.2.3 Gas adjustment device GA

[0110] The gas control processor 35 controls the gas supply device 33 and the gas exhaust device 34 based on the gas control signal received from the laser control processor 30 and the measured data of the air pressure P, so that the air pressure P inside the laser cavity 10 becomes a desired value.

[0111] For example, when increasing the air pressure P inside the laser cavity 10, the gas control processor 35 controls to open the valve included in the gas supply device 33 to supply laser gas to the inside of the laser cavity 10. In addition, for example, when decreasing the air pressure P inside the laser cavity 10, the gas control processor 35 controls to open the valve included in the gas exhaust device 34 to discharge a part of the laser gas inside the laser cavity 10.

[0112] 1.3 Narrowbanding device

[0113] 1.3.1 Structure

[0114] Figure 3A and Figure 3B The structure of the narrowbanding device 14 in the comparative example is schematically shown. In each figure, the V-axis, H-axis, and Z-axis perpendicular to each other are shown. Figure 3A The narrowbanding device 14 is shown as viewed along the -V direction, Figure 3B The narrowbanding device 14 is shown as viewed along the -H direction. The -V direction and +V direction are related to the electrodes 11a and 11b (refer to Figure 2)The directions facing each other are the same. The -Z direction is the same as the traveling direction of the light beam emitted from window 10a. The +Z direction is the same as the traveling direction of the pulsed laser output via the output coupling mirror 15 after being emitted from window 10b.

[0115] The narrowbanding device 14 includes first and second prisms 41 and 42 and a grating system 50.

[0116] 1.3.1.1 First and second prisms 41 and 42

[0117] The first prism 41 is disposed on the optical path of the light beam emitted from window 10a. The first prism 41 is supported by a holder 411.

[0118] The second prism 42 is disposed on the optical path of the light beam after passing through the first prism 41. The second prism 42 is supported by a holder 421.

[0119] The first and second prisms 41 and 42 are made of a material such as calcium fluoride or synthetic quartz that has a high transmittance for the selected wavelength of the narrowbanding device 14.

[0120] The first and second prisms 41 and 42 are arranged such that the surfaces of the first and second prisms 41 and 42 for the incident and outgoing light beams are both parallel to the V axis. The second prism 42 can be rotated about an axis parallel to the V axis by a rotating table 422.

[0121] 1.3.1.2 Grating system 50

[0122] The grating system 50 includes gratings 51 and 52. The gratings 51 and 52 are arranged at different positions in the V-axis direction on the optical path of the light beam after passing through the second prism 42. The directions of the grooves of the gratings 51 and 52 are the same as the V-axis direction. The positions of the gratings 51 and 52 are set such that the light beam after passing through the second prism 42 is incident across the gratings 51 and 52.

[0123] The gratings 51 and 52 are supported by a holder 511. However, the grating 51 is supported to maintain a fixed attitude, while in contrast, the grating 52 can be rotated about an axis parallel to the V axis by a rotating mechanism 522.

[0124] 1.3.2 Operation

[0125] Through each of the first and second prisms 41 and 42, the light beam emitted from window 10a changes its traveling direction in a plane parallel to the HZ plane, where the HZ plane is a plane perpendicular to the V axis, and the beam width is expanded in a plane parallel to the HZ plane. As an example, the traveling direction of the light beam passing through both the first and second prisms 41 and 42 and heading towards the gratings 51 and 52 is substantially the same as the -Z direction.

[0126] The light incident on gratings 51 and 52 from the second prism 42 is reflected by the multiple grooves of gratings 51 and 52 respectively, and diffracted in the direction corresponding to the wavelength of the light. Thus, the light reflected by the multiple grooves of gratings 51 and 52 is dispersed in a plane parallel to the HZ plane. Grating 51 is arranged in a Littrow configuration so that the incident angle of the light beam incident on grating 51 from the second prism 42 is consistent with the diffraction angle of the diffracted light of the desired first wavelength λ1. Grating 52 is arranged in a Littrow configuration so that the incident angle of the light beam incident on grating 52 from the second prism 42 is consistent with the diffraction angle of the diffracted light of the desired second wavelength λ2. When the incident angles of the light beams incident on gratings 51 and 52 from the second prism 42 are different from each other, a wavelength difference is generated between the first wavelength λ1 of the diffracted light returning from grating 51 to the second prism 42 and the second wavelength λ2 of the diffracted light returning from grating 52 to the second prism 42.

[0127] In Figure 3A and Figure 3B the dashed arrow indicating the light beam only shows the direction from the first prism 41 towards gratings 51 and 52. However, the light beam of the selected wavelength of the narrowbanding device 14 travels from gratings 51 and 52 towards the first prism 41 through a path opposite to these dashed arrows.

[0128] The second prism 42 and the first prism 41 narrow the beam width of the light returning from gratings 51 and 52 in a plane parallel to the HZ plane, and cause the light to return to the laser cavity 10 through the window 10a.

[0129] The turntable 422 and the rotation mechanism 522 are controlled by the laser control processor 30.

[0130] When the turntable 422 slightly rotates the second prism 42, the traveling direction of the light beam emitted from the second prism 42 towards gratings 51 and 52 slightly changes in a plane parallel to the HZ plane. Thus, the incident angle of the light beam incident on gratings 51 and 52 from the second prism 42 slightly changes. As a result, both the first wavelength λ1 and the second wavelength λ2 change.

[0131] When the rotation mechanism 522 slightly rotates grating 52, the incident angle of the light beam incident on grating 51 from the second prism 42 does not change, but the incident angle of the light beam incident on grating 52 from the second prism 42 slightly changes. As a result, the wavelength difference between the first wavelength λ1 and the second wavelength λ2 changes.

[0132] The exposure control processor 110 sends the target value λ1t of the first wavelength λ1 and the target value λ2t of the second wavelength λ2 to the laser control processor 30.

[0133] The laser control processor 30 controls the rotary table 422 based on the target value λ1t of the first wavelength λ1. Thereby, the rotary table 422 changes the attitude of the second prism 42, and adjusts the incident angle (the first incident angle) of the light beam incident on the grating 51 and the incident angle (the second incident angle) of the light beam incident on the grating 52.

[0134] The laser control processor 30 controls the rotary mechanism 522 based on the target value λ2t of the second wavelength λ2. Thereby, the rotary mechanism 522 changes the attitude of the grating 52, and adjusts the second incident angle of the light beam incident on the grating 52.

[0135] According to the above structure and operation, the first wavelength λ1 and the second wavelength λ2 in the light beam emitted from the window 10a of the laser cavity 10 are selected and returned into the laser cavity 10. Thereby, the narrowband gas laser device 1 can perform two-wavelength oscillation. By controlling the rotary table 422 and the rotary mechanism 522, the first wavelength λ1 and the second wavelength λ2 can also be set respectively.

[0136] The focal length of the exposure apparatus 100 (refer to Figure 1 ) depends on the wavelength of the pulsed laser. The pulsed laser output from the narrowband gas laser device 1 that performs two-wavelength oscillation can be imaged at two different positions in the direction of the optical axis of the pulsed laser in the workpiece table WT of the exposure apparatus 100, and the depth of focus can be substantially increased. For example, even when exposing a resist film with a large film thickness, it is possible to suppress the deviation of the imaging performance in the thickness direction of the resist film.

[0137] 1.3.3 Problems of the Comparative Example

[0138] In the comparative example, the first wavelength and the second wavelength can be set respectively, but the energy ratio cannot be set. Therefore, it is sometimes difficult to make the cross-sectional shape of the resist film obtained by exposing and developing the resist film into a desired shape. For example, it is sometimes difficult to make the boundary surface between the portion where the resist film is removed by exposure and development and the portion where the resist film remains on the semiconductor wafer, that is, the resist wall surface and the surface of the semiconductor wafer form a desired angle.

[0139] In several embodiments described below, the energy ratio between the first wavelength component and the second wavelength component included in the pulsed laser can be adjusted with high precision.

[0140] 2. Narrowband Gas Laser Device for Adjusting the Energy Ratio R with Reference to Table Data

[0141] 2.1 Structure

[0142] Figure 4A and Figure 4B Schematically shows the structure of the narrowband device 14a in the first embodiment. Figure 4AThe narrowbanding device 14a is shown as viewed in the -V direction. Figure 4B The narrowbanding device 14a is shown as viewed in the -H direction.

[0143] The narrowbanding device 14a includes a parallel plane substrate 61.

[0144] The parallel plane substrate 61 is arranged so as to overlap a part of the cross-section of the optical path of the light beam after passing through the second prism 42. The parallel plane substrate 61 is arranged on the optical path of the light beam between the second prism 42 and the grating 52. The parallel plane substrate 61 is supported by a holder 611. The parallel plane substrate 61 is made of a material such as calcium fluoride or synthetic quartz. The parallel plane substrate 61 is configured to be movable in the -V direction and the +V direction by a linear stage 612. The linear stage 612 corresponds to the adjustment mechanism in the present invention.

[0145] The parallel plane substrate 61 includes an incident surface 613 for a part of the light beam after passing through the second prism 42 to enter, and an exit surface 614 for the light that has entered the parallel plane substrate 61 through the incident surface 613 to exit from the inside of the parallel plane substrate 61 toward the grating 52 (see Figure 4B ). Both the incident surface 613 and the exit surface 614 are parallel to the H axis, and the incident surface 613 and the exit surface 614 are parallel to each other. The incident surface 613 and the exit surface 614 are inclined with respect to the incident direction of the light beam to bend the light beam. Specifically, the normal vector 613v of the incident surface 613 is parallel to the VZ plane, and further, the normal vector 613v has direction components in the -V direction and the +Z direction.

[0146] The memory 32 included in the laser control processor 30 (see Figure 2 ) stores relationship data representing the relationship between the parameter representing the energy ratio and the control parameter Y of the linear stage 612. The relationship data is, for example, the table data described later in Figure 8 .

[0147] The parameter of the energy ratio is a parameter related to the ratio of the energy Eλ1 and the energy Eλ2. For example, it is the energy ratio R, where the energy Eλ1 is the energy of the wavelength component of the first wavelength λ1 in the total pulse energy E of the pulsed laser output from the narrowbanding gas laser device 1, and the energy Eλ2 is the energy of the wavelength component of the second wavelength λ2. The energy ratio R is the ratio of the energy Eλ1 of the wavelength component of the first wavelength λ1 to the total pulse energy E of the pulsed laser, and is represented by the following formula.

[0148] R = Eλ1 / E

[0149] 2.2 Operation of the Narrowbanding Gas Laser Device

[0150] A first portion B1 of the light beam after passing through the second prism 42 enters the grating 51 through the outside of the parallel plane substrate 61. A second portion B2 of the light beam enters the grating 52 through the inside of the parallel plane substrate 61. That is, the narrowbanding device 14a including the parallel plane substrate 61 causes the first portion B1 of the light beam to enter the grating 51 and causes the second portion B2 of the light beam to enter the grating 52. At this time, the parallel plane substrate 61 shifts the optical axis of the second portion B2 of the light beam in the +V direction with respect to the optical axis of the first portion B1. The optical axis refers to the central axis of the optical path. In this way, the parallel plane substrate 61 adjusts the optical path of a portion of the light beam by allowing a portion of the light beam to pass through.

[0151] In addition, the linear stage 612 changes the ratio of the first portion B1 to the second portion B2 by changing the position of the parallel plane substrate 61 in the V-axis direction.

[0152] When the second portion B2 of the light beam incident on the parallel plane substrate 61 in the light beam increases by moving the parallel plane substrate 61 in the -V direction, the light incident on the grating 52 increases. Therefore, the energy Eλ2 of the wavelength component of the second wavelength λ2 included in the pulsed laser becomes larger.

[0153] When the second portion B2 of the light beam incident on the parallel plane substrate 61 in the light beam decreases by moving the parallel plane substrate 61 in the +V direction, the light incident on the grating 52 decreases. Therefore, the energy Eλ2 of the wavelength component of the second wavelength λ2 included in the pulsed laser becomes smaller.

[0154] The moving direction of the parallel plane substrate 61 realized by the linear stage 612 may not be the V-axis direction. The linear stage 612 only needs to move the parallel plane substrate 61 in a direction intersecting the HZ plane, where the HZ plane is a plane perpendicular to the V axis.

[0155] The exposure control processor 110 sends various command values for two-wavelength oscillation to the laser control processor 30. The command values for two-wavelength oscillation include the target value λ1t of the first wavelength λ1, the target value λ2t of the second wavelength λ2, the target value Rt of the energy ratio R, and the target value Et of the total pulse energy E.

[0156] The laser control processor 30 controls the linear stage 612 according to the target value Rt of the energy ratio R. Thereby, the linear stage 612 adjusts the position of the parallel plane substrate 61 and adjusts the energy ratio R of the wavelength component of the first wavelength λ1 selected by the grating 51 and the wavelength component of the second wavelength λ2 selected by the grating 52.

[0157] The laser control processor 30 controls the rotary stage 422 according to the target value λ1t of the first wavelength λ1. Thereby, the rotary stage 422 changes the attitude of the second prism 42 and adjusts the first incident angle of the first part B1 of the light beam onto the grating 51.

[0158] The laser control processor 30 controls the rotary mechanism 522 according to the target value λ2t of the second wavelength λ2. Thereby, the rotary mechanism 522 changes the attitude of the grating 52 and adjusts the second incident angle of the second part B2 of the light beam onto the grating 52.

[0159] 2.3 Control of two-wavelength oscillation by the laser control processor 30

[0160] Figure 5 is a flowchart showing the processing procedure of two-wavelength oscillation in the first embodiment. The laser control processor 30 performs laser control of two-wavelength oscillation through the following processing.

[0161] In S1, the laser control processor 30 receives various instruction values of two-wavelength oscillation from the exposure control processor 110 of the exposure apparatus 100. Specific examples of the instruction values of two-wavelength oscillation are as described with reference to Figure 4B as follows.

[0162] Next, in S2, the laser control processor 30 closes the shutter 18. Thereby, the pulsed laser does not enter the exposure apparatus 100.

[0163] Next, in S3, the laser control processor 30 performs wavelength control of two-wavelength oscillation. The wavelength control of two-wavelength oscillation is described with reference to Figure 6 which will be described later.

[0164] Next, in S5, the laser control processor 30 performs energy control of two-wavelength oscillation. The energy control of two-wavelength oscillation is described with reference to Figure 7 which will be described later.

[0165] Next, in S7, the laser control processor 30 opens the shutter 18. Thereby, the pulsed laser can enter the exposure apparatus 100.

[0166] Next, in S8, the laser control processor 30 sends a ready-OK signal to the exposure control processor 110 of the exposure apparatus 100. After S8, the laser control processor 30 ends the processing of this flowchart.

[0167] 2.3.1 Wavelength control of two-wavelength oscillation

[0168] Figure 6 is a flowchart showing the processing procedure of wavelength control of two-wavelength oscillation. Figure 6 The processing shown corresponds to Figure 5 the subroutine of S3.

[0169] In S31, the laser control processor 30 starts the adjustment oscillation for setting the wavelength.

[0170] Next, in S32, the laser control processor 30 uses the optical detector 17 to detect the first wavelength λ1 and the second wavelength λ2.

[0171] Next, in S33, the laser control processor 30 reads the target value λ1t of the first wavelength λ1 and the target value λ2t of the second wavelength λ2 from the memory 32 (refer to Figure 2 ). Then, the laser control processor 30 calculates the differences Δλ1 and Δλ2 between the first wavelength λ1 and the second wavelength λ2 detected in S32 and their respective target values λ1t and λ2t using the following formulas.

[0172] Δλ1 = λ1 - λ1t

[0173] Δλ2 = λ2 - λ2t

[0174] Next, in S34, the laser control processor 30 determines whether the absolute value |Δλ1| of the difference Δλ1 is less than the specified value Δλ1L. If the absolute value |Δλ1| of the difference Δλ1 is greater than or equal to the specified value Δλ1L (S34: No), the laser control processor 30 proceeds to S35. If the absolute value |Δλ1| of the difference Δλ1 is less than the specified value Δλ1L (S34: Yes), the laser control processor 30 proceeds to S36.

[0175] In S35, the laser control processor 30 controls the turntable 422 of the second prism 42 to reduce the absolute value |Δλ1| of the difference Δλ1. After S35, the laser control processor 30 returns the process to S32. In this way, the laser control processor 30 controls the turntable 422 of the second prism 42 to make the first wavelength λ1 approach its target value λ1t.

[0176] In S36, the laser control processor 30 determines whether the absolute value |Δλ2| of the difference Δλ2 is less than the specified value Δλ2L. If the absolute value |Δλ2| of the difference Δλ2 is greater than or equal to the specified value Δλ2L (S36: No), the laser control processor 30 proceeds to S37. If the absolute value |Δλ2| of the difference Δλ2 is less than the specified value Δλ2L (S36: Yes), the laser control processor 30 proceeds to S38.

[0177] In S37, the laser control processor 30 controls the rotation mechanism 522 of the grating 52 to reduce the absolute value |Δλ2| of the difference Δλ2. After S37, the laser control processor 30 returns the process to S32. In this way, the laser control processor 30 controls the rotation mechanism 522 of the grating 52 to make the second wavelength λ2 approach its target value λ2t.

[0178] In S38, the laser control processor 30 stops adjusting the oscillation. After S38, the laser control processor 30 ends the process of this flowchart and returns Figure 5 to the process shown.

[0179] 2.3.2 Energy Control of Dual-Wavelength Oscillation

[0180] Figure 7 is a flowchart showing the process of energy control of dual-wavelength oscillation. Figure 7 The process shown is equivalent to Figure 5 the subroutine of S5 in

[0181] In S52, the laser control processor 30 retrieves the table data stored in the memory 32 and obtains the value of the control parameter Y of the linear stage 612 corresponding to the target value Rt of the energy ratio R.

[0182] Next, in S53, the laser control processor 30 controls the linear stage 612 according to the value of the control parameter Y obtained from the table data.

[0183] Next, in S54, the laser control processor 30 starts the adjustment oscillation for setting the pulse energy.

[0184] Next, in S55, the laser control processor 30 measures the total pulse energy E of the pulsed laser through the optical detector 17. The total pulse energy E of the pulsed laser is the energy of one pulse of the pulsed laser, which is equivalent to the sum of the energy Eλ1 of the wavelength component of the first wavelength λ1 and the energy Eλ2 of the wavelength component of the second wavelength λ2.

[0185] Then, the laser control processor 30 calculates the difference ΔE between the detected total pulse energy E and the target value Et of the total pulse energy E using the following formula.

[0186] ΔE = E - Et

[0187] Next, in S56, the laser control processor 30 determines whether the absolute value |ΔE| of the difference ΔE is less than the specified value ΔEL. When the absolute value |ΔE| of the difference ΔE is greater than or equal to the specified value ΔEL (S56: No), the laser control processor 30 makes the process enter S57. When the absolute value |ΔE| of the difference ΔE is less than the specified value ΔEL (S56: Yes), the laser control processor 30 makes the process enter S58.

[0188] In S57, the laser control processor 30 changes the charging voltage HV by the following formula.

[0189] HV = HV - ΔE·α

[0190] Here, α is a positive constant. For example, when the total pulse energy E is greater than the target value Et, the charging voltage HV is decreased according to the difference ΔE, thereby reducing the total pulse energy E and enabling the total pulse energy E to approach the target value Et. After S57, the laser control processor 30 returns the process to S55.

[0191] In S58, the laser control processor 30 stops adjusting the oscillation. After S58, the laser control processor 30 ends the process of this flowchart and returns Figure 5 to the

[0192] Figure 8 Conceptually shows the table data stored in the memory 32. The table data is data that correlates the control parameter Y of the linear stage 612 and the energy ratio R when controlling the linear stage 612 using the control parameter Y. The control parameter Y of the linear stage 612 is, for example, a parameter that specifies the position in the V-axis direction of the parallel plane substrate 61. In Figure 8 , the characters or numbers in parentheses indicate the correspondence between the control parameter Y and the energy ratio R. I is an integer of 1 or more, and i represents each integer from 0 to I.

[0193] Figure 9 is a graph illustrating the relationship between the control parameter Y of the linear stage 612 and the energy ratio R. When the control parameter Y is the central value Y(I / 2), the energy ratio R can be 50%. The curve of the graph can have a rotationally symmetric shape centered on the point where the energy ratio R is 50%.

[0194] As Figure 9 shown, within the range where the energy ratio R is greater than 0% and less than 100%, the energy ratio R is in a monotonically increasing relationship with respect to the control parameter Y. Therefore, when specifying the target value Rt of the energy ratio R within the range greater than 0% and less than 100%, the necessary control parameter Y can be uniquely determined.

[0195] Regarding other aspects, the structure and operation of the first embodiment are the same as those of the comparative example.

[0196] 2.4 Function

[0197] In the first embodiment, the adjustment mechanism, i.e., the linear stage 612, adjusts the energy ratio R between the first wavelength component and the second wavelength component of the pulsed laser. The laser control processor 30 stores relationship data representing the relationship between the parameter indicating the energy ratio R and the control parameter Y of the adjustment mechanism. The laser control processor 30 receives, in Figure 5 S1 of Figure 7 , an instruction value of the parameter of the energy ratio R from the exposure control processor 110 of the external device, i.e., the exposure device 100, and obtains, in S52 and S53 of

[0198] , the value of the control parameter Y corresponding to the instruction value according to the above relationship data, and controls the adjustment mechanism based on this value. Thus, the energy ratio R between the first wavelength component and the second wavelength component of the pulsed laser can be adjusted with high precision. In addition, even when a photodetector for measuring the energy ratio is not provided in the narrowband gas laser device 1, the energy ratio R can be adjusted. Moreover, an angle desired between the resist wall surface obtained by performing exposure and development using this pulsed laser and the surface of the semiconductor wafer can be formed. Figure 7 Before controlling the adjustment mechanism in S53 of Figure 6 , in the first embodiment, the laser control processor 30 controls the postures of the second prism 42 and the grating 52 through the processing of

[0199] to make the respective wavelengths λ1 and λ2 of the first wavelength component and the second wavelength component approach their respective target values λ1t and λ2t. When the first wavelength λ1 and the second wavelength λ2 are changed, the diffraction efficiency in the gratings 51 and 52 changes, and sometimes the energy ratio R changes. By adjusting the first wavelength λ1 and the second wavelength λ2 before adjusting the energy ratio R using the adjustment mechanism, the adjustment of the energy ratio R can be completed with a smaller number of times. Figure 7 After controlling the adjustment mechanism in S53 of

[0200] , in the first embodiment, the laser control processor 30 measures the total pulse energy E of the pulsed laser including the first wavelength component and the second wavelength component through the processing of S55 to S57, and controls the charging voltage HV of the charger 12 to make the total pulse energy E approach the target value Et. When the energy ratio R is adjusted by the adjustment mechanism, the path of the light beam inside the optical resonator changes, and sometimes the total pulse energy E changes. By adjusting the total pulse energy E after adjusting the energy ratio R by the adjustment mechanism, the adjustment of the total pulse energy E can be completed with a smaller number of times.

[0201] 3. Narrowband gas laser device that adjusts the energy ratio R considering the charging voltage HV and the gas pressure P

[0202] The structure of the narrowband device 14a in the second embodiment is the same as that with reference to Figure 4A andFigure 4B The structure of the description is the same. The processing procedure of the two-wavelength oscillation and the wavelength control of the two-wavelength oscillation in the second embodiment are respectively the same as those described with reference to Figure 5 and Figure 6 the content described.

[0203] The difference between the second embodiment and the first embodiment is that the control parameter Y of the linear stage 612 is determined by considering not only the target value Rt of the energy ratio R, but also the charging voltage HV of the charger 12 and the air pressure P inside the laser cavity 10.

[0204] In the second embodiment, the relational data stored in the memory 32 represents the relationship of the energy ratio R with respect to the combination of the control parameter Y of the linear stage 612, the charging voltage HV of the charger 12, and the air pressure P inside the laser cavity 10. The relational data is, for example, the table data described with reference to Figure 11A and Figure 11B described later in the table.

[0205] Figure 10 is a flowchart showing the processing procedure of the energy control of the two-wavelength oscillation in the second embodiment. Figure 10 The processing shown is equivalent to Figure 5 the subroutine of S5.

[0206] In S51b, the laser control processor 30 starts the adjustment oscillation for setting the pulse energy.

[0207] The laser control processor 30 sets the charging voltage HV of the charger 12 according to the target value Et of the total pulse energy E obtained in Figure 5 S1. The laser control processor 30 receives the measurement data of the total pulse energy E from the optical detector 17, and performs feedback control on the charging voltage HV based on the target value Et of the total pulse energy E and the measurement data of the total pulse energy E. The charging voltage HV set by this feedback control is used as the first voltage HV1.

[0208] The laser control processor 30 receives the measurement data of the air pressure P inside the laser cavity 10 from the pressure sensor 16.

[0209] Next, in S52b, the laser control processor 30 retrieves the table data stored in the memory 32 and obtains the value of the control parameter Y of the linear stage 612 corresponding to the target value Rt of the energy ratio R, the first voltage HV1, and the air pressure P.

[0210] Next, in S53, the laser control processor 30 controls the linear stage 612 according to the value of the control parameter Y obtained from the table data.

[0211] The processing of the subsequent S55 to S57 is the same as that described with reference to Figure 7The same applies to the description.

[0212] When controlling the linear stage 612 to adjust the energy ratio R, sometimes the path of the light beam inside the optical resonator changes, and the total pulse energy E changes. Therefore, in S55, the total pulse energy E is measured, and based on the difference ΔE from the target value Et, in S57, the charging voltage HV is changed. The newly set charging voltage HV in S57 is used as the second voltage HV2.

[0213] After S57, the laser control processor 30 returns the process to S52b. When S52b is executed again after S57, the second voltage HV2 is used as the charging voltage HV.

[0214] When the absolute value |ΔE| of the difference ΔE between the total pulse energy E and the target value Et in S56 is less than the specified value ΔEL, in S58, the adjustment of oscillation is stopped, and then the processing of this flowchart ends, which is the same as Figure 7 the same.

[0215] Figure 11A and Figure 11B Conceptually shows the table data stored in the memory 32. The table data corresponds the energy ratio R when performing laser oscillation using a combination of these control values with the combination of the control parameter Y of the linear stage 612, the charging voltage HV of the charger 12, and the air pressure P inside the laser cavity 10. In Figure 11A and Figure 11B the characters or numbers in parentheses indicate the correspondence between the combination of the above control values and the energy ratio R. J and K are integers of 1 or more, j represents each integer from 0 to J, and k represents each integer from 0 to K.

[0216] In Figure 11A and Figure 11B as the values of the control parameter Y of the linear stage 612, only two values, Y(1) and Y(2), are shown, but the table data can also be made for more values.

[0217] In addition, the case where the energy ratio R is corresponded with the combination of the control parameter Y, the charging voltage HV, and the air pressure P has been described, but the present invention is not limited thereto.

[0218] The table data can also correspond the energy ratio R with the combination of the control parameter Y and the charging voltage HV. The laser control processor 30 can also obtain the value of the control parameter Y corresponding to the combination of the target value Rt of the energy ratio R and the charging voltage HV.

[0219] The table data can also correspond the energy ratio R with the combination of the control parameter Y and the air pressure P. The laser control processor 30 can also obtain the value of the control parameter Y corresponding to the combination of the target value Rt of the energy ratio R and the air pressure P.

[0220] Figure 12A is a graph illustrating the relationship between the control parameter Y of the linear stage 612 and the energy ratio R. In Figure 12A , it is shown that the shape of the graph may change when the gas pressure P inside the laser cavity 10 is at the first value and when the gas pressure P inside the laser cavity 10 is at the second value. That is, compared with the case where the gas pressure P is higher, the change in the energy ratio R may become steeper with respect to the change in the control parameter Y when the gas pressure P is lower.

[0221] Figure 12B is another graph illustrating the relationship between the control parameter Y of the linear stage 612 and the energy ratio R. In Figure 12B , it is shown that the shape of the graph may change when the charging voltage HV of the charger 12 is at the first value and when the charging voltage HV of the charger 12 is at the second value. That is, compared with the case where the charging voltage HV is lower, the change in the energy ratio R may become steeper with respect to the change in the control parameter Y when the charging voltage HV is higher.

[0222] As Figure 12A and Figure 12B shown, regardless of the values of the charging voltage HV and the gas pressure P, in the range where the energy ratio R is greater than 0% and less than 100%, the energy ratio R has a monotonically increasing relationship with respect to the control parameter Y. Therefore, when the charging voltage HV and the gas pressure P are determined and the target value Rt of the energy ratio R is specified in the range greater than 0% and less than 100%, the necessary control parameter Y can be uniquely determined.

[0223] Regarding other aspects, the structure and operation of the second embodiment are the same as those of the first embodiment.

[0224] 3.2 Function

[0225] In the second embodiment, the narrowband gas laser device 1 has a pulse power module 13 that applies a pulsed high voltage to a pair of electrodes 11a and 11b, and a charger 12 that holds the electric energy supplied to the pulse power module 13. The relationship data stored in the laser control processor 30 represents the relationship of the parameter of the energy ratio R with respect to the combination of the control parameter Y of the adjustment mechanism and the charging voltage HV of the charger 12. The laser control processor 30 sets the charging voltage HV of the charger 12 to the first voltage HV1, and obtains the value of the control parameter Y corresponding to the combination of the command value of the parameter of the energy ratio R and the first voltage HV1 according to the relationship data. Thereby, it is possible to adjust the energy ratio R of the first wavelength component and the second wavelength component of the pulsed laser with high precision in consideration of the charging voltage HV of the charger 12.

[0226] In the second embodiment, the laser control processor 30 is inFigure 10 In S52b, the instruction value of the parameter of the energy ratio R and the control parameter Y value corresponding to the combination of the first voltage HV1 are obtained from the relationship data, and the adjustment mechanism is controlled in S53. Then, the laser control processor 30 measures the total pulse energy E of the pulsed laser including the first wavelength component and the second wavelength component through the processes of S55 to S57, and sets the charging voltage HV of the charger 12 to the second voltage HV2 so that the total pulse energy E approaches the target value Et. Then, the laser control processor 30 returns to S52b, obtains the control parameter Y value corresponding to the combination of the instruction value of the parameter of the energy ratio R and the second voltage HV2 from the relationship data, and controls the adjustment mechanism according to the newly obtained control parameter Y value in S53.

[0227] When the energy ratio R is adjusted by the adjustment mechanism, sometimes the path of the light beam inside the optical resonator changes and the total pulse energy E changes. Therefore, after the energy ratio R is adjusted by the adjustment mechanism, the total pulse energy E is measured, and the charging voltage HV is changed from the first voltage HV1 to the second voltage HV2 according to the measurement result. After changing the charging voltage HV, the data obtained from the relationship data changes. Therefore, the new control parameter Y value is obtained again by referring to the relationship data. Thus, the energy ratio R of the first wavelength component and the second wavelength component of the pulsed laser can be adjusted with high precision considering the charging voltage HV of the charger 12.

[0228] In the second embodiment, the relationship data stored in the laser control processor 30 represents the relationship of the parameter of the energy ratio R with respect to the combination of the control parameter Y of the adjustment mechanism and the internal air pressure P of the laser cavity 10. The laser control processor 30 receives the measurement data of the internal air pressure P of the laser cavity 10, and obtains the control parameter Y value corresponding to the combination of the instruction value of the parameter of the energy ratio R and the air pressure P from the relationship data. Thus, the energy ratio R of the first wavelength component and the second wavelength component of the pulsed laser can be adjusted with high precision considering the internal air pressure P of the laser cavity 10.

[0229] In the second embodiment, the narrowband gas laser device 1 includes a pulse power module 13 that applies a pulsed high voltage to a pair of electrodes 11a and 11b, and a charger 12 that stores electric energy to be supplied to the pulse power module 13. The relational data stored in the laser control processor 30 represents the relationship of the parameter of the energy ratio R with respect to the combination of the control parameter Y of the adjustment mechanism, the charging voltage HV of the charger 12, and the gas pressure P inside the laser cavity 10. The laser control processor 30 sets the charging voltage HV of the charger 12 to the first voltage HV1, receives the measurement data of the gas pressure P inside the laser cavity 10, and obtains the value of the control parameter Y corresponding to the combination of the instruction value of the parameter of the energy ratio R, the first voltage HV1, and the gas pressure P according to the relational data. Thereby, it is possible to adjust the energy ratio R of the first wavelength component and the second wavelength component of the pulsed laser with high precision in consideration of the charging voltage HV of the charger 12 and the gas pressure P inside the laser cavity 10.

[0230] 4. Others

[0231] In the first and second embodiments, the case where the exposure control processor 110 included in the exposure device 100 outputs various instruction values for two-wavelength oscillation has been described. However, the present invention is not limited thereto. For example, these instruction values may be output by a controller of an external device (not shown) that collectively controls a plurality of exposure devices 100.

[0232] In the first and second embodiments, the narrowband gas laser device 1 including two gratings 51 and 52 and performing two-wavelength oscillation has been described. However, the present invention is not limited thereto. For example, the narrowband gas laser device 1 may also include three or more gratings, perform laser oscillation of three or more wavelengths, and obtain control parameters according to the relationship between the control parameters and the energy ratio.

[0233] In the first and second embodiments, the narrowband device 14a including the parallel plane substrate 61 has been described. However, the present invention is not limited thereto. For example, it may be configured to displace the position of the light beam by a combination of a plurality of prisms (not shown) instead of the parallel plane substrate 61, and move any one of the plurality of prisms, thereby changing the displacement amount.

[0234] In the first and second embodiments, the case where the linear stage 612 moves the parallel plane substrate 61 to displace the optical axis has been described. However, the present invention is not limited thereto. A rotary stage (not shown) may also rotate the parallel plane substrate 61 about an axis parallel to the H axis, thereby displacing the optical axis.

[0235] In the first and second embodiments, it has been described that by retrieving the table data stored in the memory 32 (refer to Figure 8 , Figure 11A , Figure 11B)However, the present invention is not limited to this case where the value of the control parameter Y is obtained. When the relationship between the energy ratio R and the control parameter Y is approximated by a curve such as Figure 9 and this curve is represented by a function, the value of the control parameter Y can also be calculated by substituting the target value Rt of the energy ratio R into the function. Alternatively, when the relationship between the energy ratio R and the combination of the control parameter Y, the charging voltage HV, and the atmospheric pressure P can be approximated by a function, the value of the control parameter Y can also be calculated by substituting the target value Rt of the energy ratio R, the charging voltage HV, and the atmospheric pressure P into the function. These functions can also be stored in the memory 32.

[0236] In the first and second embodiments, the case where the first wavelength λ1 and the second wavelength λ2 are detected and compared with the target values λ1t and λ2t respectively for wavelength control has been described. However, the present invention is not limited to this. Instead of detecting the second wavelength λ2, the wavelength difference δλ between the first wavelength λ1 and the second wavelength λ2 can be detected. That is, the first wavelength λ1 and the wavelength difference δλ can be detected and compared with the target value λ1t of the first wavelength λ1 and the target value δλt of the wavelength difference δλ respectively for wavelength control.

[0237] In the first and second embodiments, the case where the parameter of the energy ratio includes the energy ratio R, and the energy ratio R is the ratio of the pulse energy Eλ1 of the wavelength component of the first wavelength λ1 to the total pulse energy E of the pulsed laser has been described. However, the present invention is not limited to this. The parameter of the energy ratio only needs to be a parameter related to the ratio of the energy of the wavelength component of the first wavelength λ1 to the energy of the wavelength component of the second wavelength λ2. For example, the parameter of the energy ratio can also be the value obtained by dividing the pulse energy Eλ1 of the wavelength component of the first wavelength λ1 by the pulse energy Eλ2 of the wavelength component of the second wavelength λ2. In addition, for example, the parameter of the energy ratio can also be a combination of the value of the pulse energy Eλ1 of the wavelength component of the first wavelength λ1 and the value of the pulse energy Eλ2 of the wavelength component of the second wavelength λ2.

[0238] In the second embodiment, the case where the control parameter Y of the linear stage 612 is determined by considering, in addition to the target value Rt of the energy ratio R, the charging voltage HV of the charger 12 and the atmospheric pressure P inside the laser cavity 10 has been described. However, the present invention is not limited to this. The control parameter Y of the linear stage 612 can also be determined by considering the target value Rt of the energy ratio R and the charging voltage HV of the charger 12. The control parameter Y of the linear stage 612 can also be determined by considering the target value Rt of the energy ratio R and the atmospheric pressure P inside the laser cavity 10.

[0239] The above description is not restrictive, but rather a simple illustration. Therefore, it will be obvious to those skilled in the art that modifications can be made to the embodiments of the present invention without departing from the claims. In addition, it will be obvious to those skilled in the art that the embodiments of the present invention can be used in combination.

[0240] Unless otherwise expressly stated, the terms used throughout this specification and the claims should be construed as "non-limiting" terms. For example, terms such as "comprising", "all", "having", and "including" should be construed as "not excluding the existence of structural elements other than the recited structural elements". In addition, the modifier "a" should be construed to mean "at least one" or "one or more". In addition, a phrase such as "at least one of A, B, and C" should be construed as "A", "B", "C", "A + B", "A + C", "B + C", or "A + B + C". Furthermore, it should be construed to also include combinations with parts other than "A", "B", and "C".

Claims

1. A control method, which is a control method for a narrowband gas laser device that outputs pulsed laser light containing a first wavelength component and a second wavelength component. Wherein, The narrowband gas laser device has: A laser cavity that includes a pair of electrodes; An optical resonator that includes an adjustment mechanism, which is a linear stage. The linear stage adjusts the ratio between the first part of the light beam incident on the first grating and the second part of the light beam incident on the second grating by moving a parallel plane substrate, thereby adjusting the parameter of the energy ratio between the first wavelength component and the second wavelength component; And A processor that stores relationship data representing the relationship between the parameter of the energy ratio and the control parameter of the adjustment mechanism. The control method includes the following steps: Receiving an instruction value of the parameter of the energy ratio from an external device; and Obtaining the value of the control parameter corresponding to the instruction value according to the relationship data, and controlling the adjustment mechanism according to the value of the control parameter.

2. The control method according to claim 1, Wherein, The control method further includes the following step: Before controlling the adjustment mechanism, controlling the narrowband gas laser device so that the wavelengths of the first wavelength component and the second wavelength component respectively approach their target values.

3. The control method according to claim 1, Wherein, The control method further includes the following step: After controlling the adjustment mechanism, measuring the total pulse energy of the pulsed laser light containing the first wavelength component and the second wavelength component, and controlling the narrowband gas laser device so that the total pulse energy approaches the target value.

4. The control method according to claim 1, Wherein, The parameter of the energy ratio includes the ratio of the pulse energy of the first wavelength component to the total pulse energy of the pulsed laser light containing the first wavelength component and the second wavelength component.

5. The control method according to claim 1, Wherein, The parameter of the energy ratio includes the value of the pulse energy of the first wavelength component and the value of the pulse energy of the second wavelength component.

6. The control method according to claim 1, Wherein, The narrowband gas laser device further has: A pulse power module that applies a pulsed high voltage to the pair of electrodes; and A charger that holds the electric energy for supplying to the pulse power module. The relationship data represents the relationship between the parameter of the energy ratio and the following combination: The combination is the combination of the control parameter of the adjustment mechanism and the charging voltage of the charger. The control method further includes the following step: Setting the charging voltage of the charger to a first voltage. According to the relationship data, obtaining the value of the control parameter corresponding to the combination of the instruction value and the first voltage.

7. The control method according to claim 6, Wherein, After controlling the adjustment mechanism, Measuring the total pulse energy of the pulsed laser light containing the first wavelength component and the second wavelength component. Set the charging voltage of the charger to the second voltage so that the total pulse energy approaches the target value. Then, obtain the value of the control parameter corresponding to the combination of the command value and the second voltage according to the relationship data. Control the adjustment mechanism according to the newly obtained value of the control parameter.

8. The control method according to claim 1, wherein, the relationship data represents the relationship of the parameter of the energy ratio with respect to the following combination: the combination is the combination of the control parameter of the adjustment mechanism and the air pressure inside the laser cavity. The control method further includes the following steps: receiving measurement data of the air pressure inside the laser cavity. Obtain the value of the control parameter corresponding to the combination of the command value and the air pressure according to the relationship data.

9. The control method according to claim 1, wherein, the narrowband gas laser device further has: a pulse power module that applies a pulsed high voltage to the pair of electrodes; and a charger that holds the electric energy supplied to the pulse power module. The relationship data represents the relationship of the parameter of the energy ratio with respect to the following combination: the combination is the combination of the control parameter of the adjustment mechanism, the charging voltage of the charger, and the air pressure inside the laser cavity. The control method further includes the following steps: Set the charging voltage of the charger to the first voltage; and Receive measurement data of the air pressure inside the laser cavity. Obtain the value of the control parameter corresponding to the combination of the command value, the first voltage, and the air pressure according to the relationship data.

10. The control method according to claim 9, wherein, after controlling the adjustment mechanism, Measure the total pulse energy of the pulsed laser including the first wavelength component and the second wavelength component. Set the charging voltage of the charger to the second voltage so that the total pulse energy approaches the target value. Then, obtain the value of the control parameter corresponding to the combination of the command value, the second voltage, and the air pressure according to the relationship data. Control the adjustment mechanism according to the newly obtained value of the control parameter.

11. A narrowband gas laser device that outputs a pulsed laser including a first wavelength component and a second wavelength component. wherein, the narrowband gas laser device has: a laser cavity that includes a pair of electrodes; an optical resonator that includes an adjustment mechanism, the adjustment mechanism being a linear stage, and the linear stage adjusts the ratio between the first part of the beam incident on the first grating and the second part of the beam incident on the second grating by moving a parallel plane substrate, thereby adjusting the parameter of the energy ratio between the first wavelength component and the second wavelength component. and a processor that stores relationship data representing the relationship of the parameter of the energy ratio with respect to the control parameter of the adjustment mechanism. The processor receives the command value of the parameter of the energy ratio from an external device, obtains the value of the control parameter corresponding to the command value according to the relationship data, and controls the adjustment mechanism according to the value of the control parameter.

12. The narrowband gas laser device according to claim 11, wherein, before controlling the adjustment mechanism, the processor controls the narrowband gas laser device so that the wavelengths of the first wavelength component and the second wavelength component approach their respective target values.

13. The narrowband gas laser device according to claim 11, wherein, after controlling the adjustment mechanism, the processor measures the total pulse energy of the pulsed laser including the first wavelength component and the second wavelength component, and controls the narrowband gas laser device so that the total pulse energy approaches the target value.

14. The narrowband gas laser device according to claim 11, wherein, the parameter of the energy ratio includes the ratio of the pulse energy of the first wavelength component to the total pulse energy of the pulsed laser including the first wavelength component and the second wavelength component.

15. The narrowband gas laser device according to claim 11, wherein, the parameter of the energy ratio includes the value of the pulse energy of the first wavelength component and the value of the pulse energy of the second wavelength component.

16. The narrowband gas laser device according to claim 11, wherein, the narrowband gas laser device further includes: a pulse power module that applies a pulsed high voltage to the pair of electrodes; and a charger that holds the electric energy for supplying to the pulse power module, the relationship data represents the relationship of the parameter of the energy ratio with respect to the following combination: the combination is the combination of the control parameter of the adjustment mechanism and the charging voltage of the charger, the processor sets the charging voltage of the charger to a first voltage, and obtains the value of the control parameter corresponding to the combination of the command value and the first voltage according to the relationship data.

17. The narrowband gas laser device according to claim 16, wherein, after controlling the adjustment mechanism, the processor measures the total pulse energy of the pulsed laser including the first wavelength component and the second wavelength component, sets the charging voltage of the charger to a second voltage so that the total pulse energy approaches the target value, then obtains the value of the control parameter corresponding to the combination of the command value and the second voltage according to the relationship data, and controls the adjustment mechanism according to the newly obtained value of the control parameter.

18. The narrowband gas laser device according to claim 11, wherein, the relationship data represents the relationship of the parameter of the energy ratio with respect to the following combination: the combination is the combination of the control parameter of the adjustment mechanism and the air pressure inside the laser cavity, the processor receives the measurement data of the air pressure inside the laser cavity, and obtains the value of the control parameter corresponding to the combination of the command value and the air pressure according to the relationship data.

19. The narrowband gas laser device according to claim 11, wherein, the narrowband gas laser device further includes: a pulse power module that applies a pulsed high voltage to the pair of electrodes; and A charger that holds electric energy to be supplied to the pulse power module The relational data represents the relationship of the parameter of the energy ratio with respect to a combination of the control parameter of the adjustment mechanism, the charging voltage of the charger, and the air pressure inside the laser cavity The processor sets the charging voltage of the charger to a first voltage, receives measurement data of the air pressure inside the laser cavity, and obtains the value of the control parameter corresponding to the combination of the command value, the first voltage, and the air pressure according to the relational data 20. A method for manufacturing an electronic device, comprising the following steps Generating pulsed laser light using a narrow-band gas laser device Outputting the pulsed laser light to an exposure device Exposing the pulsed laser light on a photosensitive substrate in the exposure device to manufacture an electronic device The narrow-band gas laser device outputs the pulsed laser light including a first wavelength component and a second wavelength component The narrow-band gas laser device includes A laser cavity that includes a pair of electrodes An optical resonator that includes an adjustment mechanism, the adjustment mechanism being a linear stage that adjusts the ratio between the first portion of the light beam incident on the first grating and the second portion of the light beam incident on the second grating by moving a parallel plane substrate, thereby adjusting the parameter of the energy ratio between the first wavelength component and the second wavelength component; and A processor that stores relational data representing the relationship of the parameter of the energy ratio with respect to the control parameter of the adjustment mechanism, the processor receives a command value of the parameter of the energy ratio from an external device, obtains the value of the control parameter corresponding to the command value according to the relational data, and controls the adjustment mechanism according to the value of the control parameter

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