JP2003124554A - Laser device and aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser device that easily controls to decrease the wavelength component not selected. SOLUTION: This laser device is provided with a laser resonator that comprises a laser chamber 1 and an ignition electrode 12 and generates laser beam containing at least first and second wavelength components, a wavelength selective means 100 that makes the laser resonator mainly generate the first wavelength component, a gas controller 9 that adjusts laser gas filling the laser chamber, a power source part 11 that applies voltage to the ignition electrode, a detecting means 200 that detects intensity of the laser beam outputted from the laser resonator for a plurality of wavelength components, and a control means 8 that controls at least one out of the wavelength selective means, the gas controller and the power source part based on at least the intensity of the first and second wavelength components detected by the detecting means.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates generally to laser devices, and more particularly to F ₂ (molecular fluorine).
ne) as a laser medium. further,
The present invention relates to an exposure apparatus using such a laser device.

[0002]

2. Description of the Related Art As the degree of integration of semiconductor devices has improved, 70
As a light source of an exposure apparatus for realizing a fine pattern of nm or less, a light source that emits light having a wavelength of 160 nm or less is required. In particular, an F ₂ laser device that emits light having a wavelength near 157 nm is regarded as a potential light source.

The projection optical system of the exposure apparatus is roughly classified into a dioptric system composed of only a refractive lens.
ystem) and a catadioptric system in which a reflecting mirror and a refracting lens are combined. The refraction system is a projection optical system that has been widely used in conventional exposure apparatuses, but the correction of chromatic aberration of lenses is a major problem. Conventionally, by combining optical elements such as a plurality of lenses having different refractive indices,
The chromatic aberration is corrected for a plurality of wavelength components included in the light generated by the light source. However, as a material having sufficient transmissivity for light in the wavelength region near 157 nm generated by the F ₂ laser device, there is a situation in which materials other than CaF ₂ cannot be used. On the other hand, when a catadioptric projection optical system is used, the occurrence of chromatic aberration can be suppressed. Spectral line width of the output light of the plurality of selectively oscillated to line select F ₂ laser device one line of the oscillation lines in the F ₂ laser is about 1 pm, as the projection optical system of the exposure apparatus, a certain Exposure is performed using a catadioptric system capable of correcting chromatic aberration.

However, since the F ₂ laser device has a high gain, the wavelength component that has not been line-selected by the wavelength-selecting optical device installed on the rear side of the laser resonator causes ASE (amplified spontaneous emission: amplified sponteni).
ous emission). That is, when the light propagating from the rear side to the front side of the inter-electrode discharge area (gain area) is amplified and output as it is, the wavelength selection is not performed.

By the way, Japanese Patent Laid-Open No. 2000-286494 discloses a laser device equipped with an ASE monitor for detecting ASE light and determining the state of the mixed gas in the chamber based on the ASE detection signal. . FIG. 22
Shows the configuration of such a device. In FIG. 22, a pair of discharge electrodes 12 composed of an anode electrode and a cathode electrode are arranged in the laser chamber 1. Further, windows 2 and 3 are arranged on the rear side wall and the front side wall of the laser chamber 1 so as to form a predetermined Brewster angle with the optical axis passing through the laser chamber 1. A rear optical module 10 is arranged on the rear side of the laser chamber 1, and a wavelength selection optical element for selecting a desired wavelength can be included therein.

On the front side of the laser chamber 1, on the right side of the window 3, a front mirror 16 which is a partial reflection mirror and a monitor module 4 are arranged. The monitor module 4 includes a beam splitter 5 for splitting the laser light that has passed through the front mirror 16 and causing a part of the laser light to enter the ASE monitor 6 and the energy monitor 7. The ASE detection signal output from the ASE monitor 6 is input to the controller 8. Controller 8
Controls the state of the mixed gas (gas species and respective amounts) via the gas controller 9 based on this ASE detection signal, and also controls the high-voltage power supply 11.

In the free-run F ₂ laser system, C.
J. Sansonetti et. Al., Appl. Opt., 40, 1974, 2001
23, six oscillation lines (λ1 to λ6) as shown in FIG. 23 have been confirmed. When He gas is used as the buffer gas, λ3 and λ6 cannot be confirmed, but when Ne gas is used, six oscillation lines λ1 to λ6 can be confirmed. In FIG. 23, λ
The reference numerals are 1, 2, λ2, .... In the exposure apparatus, the λ1 component (λ1 = 15) having the highest intensity is usually used.
(7.63 nm) is selected for use. At this time, the second highest intensity λ2 component (λ2 = 157.52 nm)
The remaining wavelength components including is a factor that significantly reduces the resolution of the projection optical system even if it is 1% or less. Therefore, in the line select F ₂ laser apparatus, it is necessary to suppress the intensity of the remaining wavelength components (λ2 to λ6) including the λ2 component to the intensity equal to or lower than the specification value specified in the exposure apparatus.

Referring again to FIG. 22, in the case of the F ₂ laser device in which the rear optical module 10 including the wavelength selection optical element is arranged on the rear side, most of the λ2 component is ASE.
Caused by. However, as shown in FIG. 24, the ASE light also contains the λ1 component, and it is necessary to monitor each wavelength component in order to accurately control the intensity of the λ2 component. For example, in order to make a single line, pay attention to the first and second strongest wavelength components,
Λ2 extinction ratio (Iλ ₂ / (Iλ ₁ + I
It is necessary to keep λ ₂ )) below the specified value.

In Japanese Patent Laid-Open No. 2000-286494, each wavelength component is not monitored,
ASE light including all wavelength components (I _ASE λ ₁ + I _ASE λ ₂ +.
・ ・) Is detected by the ASE monitor and is targeted for deletion. As a result, the AS of the selected λ1 component
Even I _ASE λ _1, which is E light, is targeted for erasure. Therefore, it is difficult to directly control the attenuation of the λ2 component with respect to the λ1 component. Furthermore, A
Even if the ASE light is detected by the SE monitor, it is impossible to obtain the λ2 extinction ratio.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a laser device that can be easily controlled to reduce unselected wavelength components. To aim. A further object of the present invention is to provide an exposure apparatus using such a laser device.

[0011]

In order to solve the above problems, a laser device according to a first aspect of the present invention comprises a laser chamber filled with a laser gas and a discharge electrode for exciting and activating the laser gas. Including at least the first
And a laser resonator for generating a laser beam having a second wavelength component and a second wavelength component, and arranged inside the laser resonator,
A wavelength selecting unit that mainly generates a first wavelength component in the laser resonator, a gas controller that adjusts the laser gas with which the laser chamber is filled, a power supply unit that applies a voltage to the discharge electrode, and an output from the laser resonator. Detecting means for detecting the intensity of the laser light for a plurality of wavelength components; wavelength selecting means and a gas controller based on at least the intensity of the first wavelength component and the intensity of the second wavelength component detected by the detecting means. And a control means for controlling at least one of the power supply unit.

A laser device according to a second aspect of the present invention includes a laser chamber filled with a laser gas and a discharge electrode for exciting and activating the laser gas,
A laser resonator that generates laser light having at least a first wavelength component and a second wavelength component, and a first laser light that is disposed outside the laser resonator and is included in the laser light generated by the laser resonator. A wavelength selection unit that emits a wavelength component and a second wavelength component in different directions, a gas controller that adjusts the laser gas filled in the laser chamber, a power supply unit that applies a voltage to the discharge electrode, and a wavelength from the laser resonator. Based on the detection means for detecting the intensity of the laser light output through the selection means for a plurality of wavelength components, and the intensity of at least the first wavelength component and the intensity of the second wavelength component detected by the detection means. And a control means for controlling at least one of the wavelength selection means, the gas controller, and the power supply section.

Further, an exposure apparatus according to the present invention comprises the above laser device and an exposure device which exposes an object using a laser beam generated by the laser device.

In the present invention, not the spontaneous emission component (ASE) of the laser light is detected, but the intensity of the laser light is detected for a plurality of wavelength components, thereby effectively reducing the unselected wavelength components. be able to.
For example, the partial pressure of F ₂ gas in the laser chamber can be known by monitoring the intensities of the λ1 component and the λ2 component. the intensity of the λ2 component is dependent on F ₂ gas partial pressure, by F ₂ gas partial pressure performs the open control such that the predetermined value or less, it is possible to control the intensity of the λ2 component. Further, by performing feedback control of the partial pressure of F ₂ gas, it is possible to control not only the intensity of the λ2 component, but also the output energy, pulse width, spectrum width, spectrum purity, and the like.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to the same components, and the description thereof will be omitted.

FIG. 1 shows the configuration of a laser device according to the first embodiment of the present invention. In FIG. 1, the laser device is
The laser resonator includes a λ1 component (center wavelength: 157.63 nm) and a remaining wavelength component (λ2 to λ6) including a λ2 component (center wavelength: 157.52 nm). The laser chamber 1 of the laser resonator is filled with a mixed gas containing F ₂ gas, He gas, Ne gas or the like as a laser medium at several atmospheric pressure. Controller 8
Under the control of 1, the gas controller 9 can inject at least one type of gas and exhaust the mixed gas even during laser oscillation.

A pair of discharge electrodes 12 are arranged in the laser chamber 1 so as to face each other in a direction orthogonal to the plane of the drawing. Between the electrodes, a high voltage power source 11 such as a pulse power module is used to generate a pulse-shaped high voltage. The voltage HV is applied. The voltage to be applied by the high voltage power supply 11 can be controlled by the controller 8. When a laser medium is supplied into the laser chamber 1 and a high voltage is applied between the electrodes to cause discharge, light is emitted from the laser medium.

Windows 2 and 3 are provided on the rear and front walls of the laser chamber 1, respectively.
It is arranged so as to form a predetermined Brewster angle with the optical axis penetrating through. On the rear side of the laser chamber 1, a wavelength selection device 100 for selecting a line of wavelength λ1 is arranged.

The wavelength component (λ1) selected by the wavelength selection device 100 enters the laser chamber 1 from the window 2, and the amplified laser light passes from the laser chamber 1 through the window 3 and the spatial filter 15 (slit). Then, while resonating with the front mirror 16, a part thereof is output to the outside of the laser resonator. The laser light emitted from the front mirror 16 is monitored by the monitor module 20.
It is emitted toward 0.

The laser light emitted from the front mirror 16 is split into a first direction (right side in the figure) and a second direction (lower side in the figure) by the beam splitter 5 arranged in the monitor module 200. . The laser light that has passed through the first direction is input to the exposure device as the output light of the laser device. On the other hand, the laser light reflected in the second direction is reflected by the beam splitter 20 installed below the beam splitter 5.
5 is further divided into two directions, one is incident on the wavelength sensor 210 and the other is incident on the energy monitor 220.

The detection signal output from the wavelength sensor 210 (intensity Airamuda ₁ of λ1 component, .lambda.2 component intensity Iλ _2, λ3 component intensity Iλ _3, ···) on the basis of the extinction ratio is calculated. The extinction ratio is extinction ratio = Iλ
₂ / (Iλ ₁ + Iλ ₂ ), or more easily, the extinction ratio = Iλ ₂ / Iλ ₁ . Alternatively, the remaining wavelength components including the λ2 component may be targeted. That is more accurate. When He is used as the buffer gas, the extinction ratio = (Iλ ₂ + Iλ ₄
+ Iλ ₅ ) / (Iλ ₁ + Iλ ₂ + Iλ ₄ + Iλ ₅ ). Further, when Ne is used as the buffer gas, the extinction ratio = (Iλ ₂ + Iλ ₃ + Iλ ₄ + Iλ ₅ + Iλ ₆ ) / (I
λ ₁ + Iλ ₂ + Iλ ₃ + Iλ ₄ + Iλ ₅ + Iλ ₆ ).

If the red light emitting component from the fluorine atom is strong, it adversely affects the exposure apparatus. Therefore, it is preferable to add the intensity Iλ _red of the red light emitting component to the extinction ratio calculation item. In this case, for example, extinction ratio = (Iλ ₂ + Iλ ₃
+ Iλ ₄ + Iλ ₅ + Iλ ₆ + Iλ _red ) / (Iλ ₁ + Iλ ₂ + Iλ ₃ + I
Calculate as λ ₄ + Iλ ₅ + Iλ ₆ + Iλ _red ).

Based on the measurement result of the wavelength sensor,
The controller 8 controls the laser input parameters.
The laser input parameters include the partial pressure of F ₂ gas, the total gas pressure, the applied voltage (HV), the angle or position of the wavelength selection element, and the like. In this control, it is preferable that the extinction ratio calculated by the above equation be equal to or less than the specification value of the exposure apparatus.

FIG. 2 is a graph showing the dependence of the λ2 extinction ratio on the partial pressure of F ₂ gas. The horizontal axis in Fig. 2 is 1% due to He gas.
It means the amount of fluorine gas diluted to 1 to be supplied into the laser chamber. For example, the F ₂ / He gas partial pressure on the horizontal axis is 40
The point of 0 hPa means that out of the total gas pressure = 2700 hPa, the pressure of the fluorine gas diluted to 1% with He gas is 400 hPa, and that of fluorine gas alone is 4 hPa. Here, the total gas pressure is constant, and the applied voltage (HV) is 25 kV, 23 kV, and 20 kV.
The relationship between the gas partial pressure of 1% F ₂ / He and the λ2 extinction ratio is obtained for each kV. As can be seen from FIG. 2, the slope of the graph differs depending on the applied voltage.
₂ By reducing the gas partial pressure, the λ2 extinction ratio becomes smaller. Therefore, in order to reduce the λ2 extinction ratio, F ₂
It may be controlled so as to reduce the gas partial pressure.

FIG. 3 is a graph showing the dependence of the λ2 extinction ratio on the total gas pressure. Here, the gas partial pressure of 1% F ₂ / He is constant, and the applied voltage (HV) is 25 kV, 2
The relationship between the total gas pressure and the λ2 extinction ratio is obtained for each of 3 kV and 20 kV. The F ₂ / He gas partial pressure is the pressure occupied by 1% F ₂ / He gas with respect to the total gas pressure in the laser chamber, as described in paragraph “0024”. Thus, the λ2 extinction ratio can be controlled by using the total gas pressure and the applied voltage as laser input parameters. However, here, the change amount of the λ2 extinction ratio (Δλ2 extinction ratio) and the change amount of the output energy (Δ
Output energy), that is, η = (Δλ2 extinction ratio)
If / (Δ output energy) is defined as the rate of change, F
_{2 When the} gas partial pressure is changed, the rate of change η is one digit larger than when other laser input parameters are changed.
showed that. Therefore, while keeping the output energy constant,
In order to change the λ2 extinction ratio, it is most suitable to use the partial pressure of F ₂ gas as the laser input parameter.

In FIG. 4, the gas partial pressure of 1% F ₂ / He is 54
The relationship between the output energy and the λ2 extinction ratio is shown for each of 0 hPa, 360 hPa, and 270 hPa. The 1% F ₂ / He gas partial pressure is the pressure occupied by the 1% F ₂ / He gas with respect to the total gas pressure in the laser chamber, as described in paragraph “0024”. As can be seen from FIG. 4, the λ2 extinction ratio can be greatly changed by changing the F ₂ gas partial pressure rather than changing the output energy. Therefore, in order to largely change the λ2 extinction ratio while keeping the output energy constant at, for example, 5 mJ, it is effective to change the F ₂ gas partial pressure. The change in the partial pressure of the F ₂ gas can be realized by, for example, simultaneously injecting the buffer gas or the halogen gas and exhausting the mixed gas, performing gas exhaust after gas injection, or performing gas injection after gas exhaust. .

FIG. 5 shows the relationship between the F ₂ gas partial pressure and the λ2 extinction ratio when the output energy is kept constant at 5 mJ. In FIG. 5, the gas partial pressure is 100% F ₂ . As shown in FIG. 5, by controlling the partial pressure of F ₂ gas, the λ2 extinction ratio can be changed while oscillating so that the output becomes stable. For example, when the exposure apparatus requires a λ2 extinction ratio of 0.1% or less, the F ₂ gas partial pressure may be controlled to be 0.28 kPa or less. This corresponds to an F ₂ concentration of 0.11% or less. Alternatively, when the exposure apparatus requires a λ2 extinction ratio of 0.05% or less, F
_{2 The} partial pressure of gas may be 0.26 kPa or less. This corresponds to an F ₂ concentration of 0.09% or less.

Thus, in order to reduce the λ2 extinction ratio,
To F₂Open control of gas partial pressure below a specified value
Is effective. Also, monitor the decrease in λ2 extinction ratio.
It can be confirmed by the wavelength sensor installed in the module.
I can do it. Furthermore, using the relationship of FIG.
F based on the ratio₂It is also possible to monitor the concentration. F₂Dark
Output from the wavelength sensor by monitoring the
F based on the detection signal ₂Feedback control of gas partial pressure
It is possible to adjust the output power in addition to the λ2 extinction ratio.
Energy, pulse width, spectral width, spectral purity
Etc. can be controlled.

In addition to this, the λ2 extinction ratio can be controlled by changing the angle or position of a wavelength dispersion element (prism or the like) or an optical element such as a mirror in the wavelength selection device. For example, in a wavelength selection device, the refractive index of an optical element may change due to a temperature change due to laser irradiation, and the optical axis may shift. When the λ2 component passes through the spatial filter due to the shift of the optical axis and the λ2 extinction ratio increases, it is effective to control the wavelength selection device.

Specific examples of the wavelength selection device used in the laser device according to the present embodiment will be described with reference to FIGS. 6 to 9. FIG. 6 shows a first specific example of a wavelength selection device using a dispersion prism as a wavelength dispersion element. Here, the wavelengths are separated by utilizing the wavelength dispersion characteristic of the optical element. In FIG. 6, the wavelength selection device 101 includes an HR (high reflection: high dispersion: 111, 112) made of dispersion prisms 111 and 112, and a dielectric having high durability with respect to light having a wavelength of about 157 nm.
high reflection) A mirror 113 is arranged. H
The R mirror 113 is arranged on the rotating stage 114, and the wavelength selecting operation is controlled by rotating the rotating stage 114 under the control of the controller 8. In this specific example, the case where two prisms are arranged is illustrated, but one or three or more prisms may be arranged.

Dispersion prism 1 arranged in the wavelength selection device
When the temperature of the optical element 11, 112 or the like rises due to the irradiation of the laser beam, the refractive index of the optical element changes, and the optical axis thereof shifts. If the optical axis is deviated, line selection is not correctly executed, and for example, the λ2 component passes through the spatial filter and is emitted from the laser resonator. Therefore, by controlling the rotary stage 114 with a control signal to rotate the HR mirror 113 about the direction orthogonal to the paper surface and restore the optical axis shift to the original state, λ
2 The extinction ratio can be reduced.

FIG. 7 shows a second specific example of a wavelength selection device using a grating as a wavelength dispersion element. In FIG. 7, the wavelength selection device 102 includes beam expander prisms 121 and 122 and a grating 123. The grating 123 is arranged on the rotary stage 124, and by controlling the rotary stage 124 with a control signal to rotate the grating 123, the deviation of the optical axis can be controlled. In the case of line select, the beam expander prism 12
1 can be omitted.

FIG. 8 shows third and fourth specific examples of the wavelength selection device using the etalon as the wavelength dispersion element. Figure 8
8A shows a wavelength selection device provided with a transmission etalon, and FIG. 8B shows a wavelength selection device provided with a rear mirror etalon.

In FIG. 8A, the wavelength selection device 10
3 includes a transmission etalon 131 arranged on the rotary stage 132 and an HR mirror 133. Here, the transmission pressure characteristic can be controlled by changing the gas pressure in the wavelength selection device 103 using the gas pressure control signal and changing the optical path length of the etalon gap. Alternatively, the transmission spectrum characteristic can be controlled by rotating the rotary stage 132.

In the wavelength selection device 104 shown in FIG. 8B, a rear mirror etalon 141 is arranged. The light reflection surface of the etalon (the surface forming the etalon gap) is orthogonal to the laser optical axis. Here, the reflection spectrum characteristic of the etalon is controlled so that the λ2 component is reflected by changing the gas pressure in the wavelength selection device 104 using the gas pressure control signal and changing the optical path length of the etalon gap. It

FIG. 9 shows a fifth specific example of a wavelength selection device using a birefringent filter as a wavelength dispersion element. In FIG. 9, the wavelength selection device 105 includes a birefringent filter 151 arranged on the moving stage 153, and a total reflection mirror 152. The birefringent filter 151 has two planes arranged so as to have an angular wedge, and light having a certain wavelength has two portions having a specific plate thickness.
After passing through it, the plane of polarization is changed. The birefringent filter 151 has a different refractive index depending on the plane of polarization of light, and can separate components having different planes of polarization in different directions.

The plate thickness of the birefringent filter 151 on the optical axis is such that the moving stage 153 is parallel to the paper surface and
It changes by moving in the direction shown by the arrow (⇔) in the figure. Here, the moving stage 15 is controlled by using the control signal.
By moving 3 and changing the FSR, that is, the transmission wavelength spectrum characteristic, the λ2 component can be separated from the λ1 component.

In the wavelength selection device shown in FIGS. 6 to 9, since the λ2 extinction ratio also changes due to the change in the refractive index of the optical element due to the temperature change caused by laser irradiation, the temperature inside the wavelength selection device is changed. It is also possible to control the λ2 extinction ratio by controlling the temperature of the optical element.

Next, a specific example of the monitor module used in the laser apparatus according to this embodiment will be described with reference to FIGS. FIG. 10 shows a first specific example of a monitor module using an etalon. Figure 10
In the above, a diffusion plate 231 is arranged below the beam splitter 5 arranged to divide the λ1 component emitted from the laser chamber into two directions, in order to make it uniform and enable accurate measurement. Below that, Etalon 2
32 and the condenser lens 234 are arranged in this order, and further, the line sensor 235 is arranged at the position of the focal length of the condenser lens 234. The line sensor 235 measures the wavelength of light based on the obtained fringe diameter.

As a material for each optical element, a wavelength of 157 nm is used.
When measuring around the ₂Can be used
preferable. However, for the etalon, fluorine does not
Pinged synthetic quartz may be used as a base material.

FIG. 11 shows a second monitor module using a grating spectroscope (Zerniter type spectroscope).
A specific example of In FIG. 11, the beam splitter 5
A mirror 246 is arranged below the mirror, and a diffusion plate 241 and a condenser lens 242 are arranged on the left side of the mirror 246. A slit plate 243 is arranged to the left of the condenser lens 242, and a concave mirror 244 is arranged further to the left. Here, the slit plate 243 and the concave mirror 24
4 is set so as to be equal to the focal length of the concave mirror 244. A concave mirror 245 is arranged below the concave mirror 244.
The light emitted from 44 is diffracted by the grating 247 and is incident on the concave mirror 245. Concave mirror 2
A line sensor 248 is arranged at a focal length of 45.

In the thus constructed grating spectroscope, the light passing through the slit 243 is collimated by the concave mirror 244, and then the grating 24
The wavelength components are separated by 8, and the respective wavelength components are incident on the concave mirror 245 as parallel light, condensed by the concave mirror 245, and detected by the line sensor 248.

The wavelength component detected by the monitor module as described above is a light amplification component (LA) due to stimulated emission.
SER) and amplified spontaneous release component (ASE). When the light incident on the monitor module includes the λ2 component and the like in addition to the λ1 component, these are separated and detected by the line sensor. Therefore, it is necessary to check whether or not an unnecessary line is output. Can be monitored. It is also possible to monitor the fluctuation of the spectral line width and wavelength. The absolute wavelength is monitored by Br lamp or Pt.
This can be performed by making a reference line near the wavelength of 157.6 nm in the lamp incident on the etalon spectroscope or the grating spectroscope.

When outputting laser light to the exposure device,
Normally, the power lock mode is used to keep the output energy constant. Generally, in order to perform power lock, gas pressure control and applied voltage (HV) control are performed. When the excitation gas in the laser chamber is oscillated for several M (mega) pulses or more, impurities are generated inside the laser chamber,
Halogen gas (fluorine and chlorine) is reduced by reacting with substances and discharge products in the laser chamber. Therefore, when the power lock control is not performed, the gas composition changes from the initial state and the output energy also decreases.

When performing the power lock control, the gas pressure in the laser chamber is changed based on the energy value detected by the monitor module in order to inject the decreasing halogen gas or to guarantee the decreasing laser output. Is adjusted (mainly increased) or the applied voltage is adjusted. Further, it is also practiced to replace a part of the gas in the laser chamber and return a part of the gas to a fresh state. In such a process, the λ2 extinction ratio changes as shown in FIG. FIG. 12 is a graph showing a change state of the λ2 extinction ratio with respect to the total number of shots. Here, the reason why the λ2 component increases is that the gas pressure is increased by the power lock control, the F ₂ gas partial pressure is increased, or the applied voltage is increased. According to this embodiment, such an increase in the λ2 component can be suppressed.

Next, a second embodiment of the present invention will be described. The laser device according to the second embodiment of the present invention is
A free-run F ₂ laser device is equipped with a wavelength sensor. FIG. 13 is a diagram showing the configuration of a laser device according to the second embodiment of the present invention. Here, the wavelength selection device 110 is arranged outside the front mirror 16, and line selection is performed outside the laser resonator.

In FIG. 13, the HR mirror 163 is arranged on the rear side of the laser chamber 1, and the front mirror 16 and the wavelength selection device 110 are arranged on the front side. In this embodiment, the spatial filter 30 is arranged at a position (several meters) apart from the wavelength selection device 110 to block wavelength components other than the selected wavelength component. Therefore, wavelength components other than the selected wavelength component also enter the monitor module arranged on the left side of the spatial filter 30. Therefore, in the wavelength sensor 210, not only the extinction ratio is measured, but also the intensity ratio of the λ1 component and the λ2 component (A =
It is also possible to obtain λ1 / (λ1 + λ2)). Therefore, the energy of the λ1 component can also be calculated by multiplying the energy intensity detected by the energy monitor 220 by A times.

Alternatively, it is also possible to disperse the wavelength component of the laser light by the dispersive element in the wavelength sensor 210, extract only the λ1 component, and monitor the energy thereof. In this case, since the red component due to the light emission from the fluorine atom is cut, a filter for cutting the red component becomes unnecessary, which is desirable from the viewpoint of durability of the monitor module.

Although not shown here, the HR mirror 163.
It is also possible to install a wavelength selection device between the window 2 on the rear side of the laser chamber 1 and a double wavelength selection type laser device.

Typical examples of the wavelength dispersion element in the wavelength selection device 110 include a prism, a birefringent filter, and a grating. FIG. 14 illustrates a wavelength selection device including a plurality of prisms and a total reflection mirror. In the wavelength selection device A1 shown in FIG.
A dispersion prism 52 is arranged below the dispersion prism 51, and a total reflection mirror 53 is arranged below the dispersion prism 52. Although the case where two dispersive prisms are arranged is illustrated here, one or three or more dispersive prisms may be arranged.

Laser light generated from chamber 1 (wavelength λ
1 (including the component of λ2) passes through the window 3 and the front mirror 16 and is refracted by the dispersion prisms 51 and 52. Here, since the component of the wavelength λ2 is refracted more than the component of the wavelength λ1, the component of the wavelength λ1 and the component of the wavelength λ2 can be separated. Since the longer the wavelength in the prism is, the smaller the refractive index is, the separated components of the wavelength λ1 and the wavelength λ2 are totally reflected by the total reflection mirror 53, and only the wavelength λ1 is output to the monitor module 200. The unselected wavelength λ2 component is emitted in the other direction and eliminated. The measurement result is sent to the controller 8 so that the component of wavelength λ1 is efficiently emitted,
The angle of the total reflection mirror 53 is feedback-controlled from the controller 8 via the mirror attitude angle control driver 54.

Since the dispersive prism has a high transmittance in the P-polarized light direction, the dispersive prism 51 is arranged so that the polarization direction of the F ₂ laser is the P-polarized light direction with respect to the incident surface of the dispersive prism 51. Is arranged, the transmittance of the dispersion prism is increased. When the material of the dispersive prism is CaF ₂ and the apex angle is 65.4 degrees, the incident angle and the exit angle to the dispersive prism can be made Brewster's angle, and the transmittance of P-polarized light can be close to 100%. can do. When the selected wavelength λ1 is 157 nm, CaF ₂ having a small birefringence is preferably used as the material of the prism.

When the laser light is output, the laser light is absorbed in the prism and the temperature of the dispersion prism rises.
The refractive index of ₂ becomes large, the angle of the beam output to the exposure device changes, and the output direction shifts. Total reflection mirror 53
By controlling the angle of 1 by the control signal, the variation of this angle can be corrected. Alternatively, in order to keep the temperature of the wavelength selection device A1 constant, the wavelength selection device A1
May be placed in the constant temperature bath 55 to adjust the temperature. The constant temperature bath 55 is provided with windows 56 and 57 for passing laser light.

FIG. 15 exemplifies a wavelength selection device in which a plurality of 45-degree right angle prisms and a plurality of dispersion prisms are arranged so that the optical axis of incident light and the optical axis of emitted light coincide with each other.
In the wavelength selection device A2 shown in FIG. 15, the laser light (including the components of wavelengths λ1 and λ2) generated by the laser chamber 1 passes through the window 3 and the front mirror 16 and is reflected by the right-angle prism 91 to be a dispersion prism. It is incident on 92. The dispersion prisms 92 and 93 separate the wavelength λ1 component and the wavelength λ2 component, and the 45 ° right-angle prism 95 reflects them in the incident direction. The laser light passing through the dispersion prisms 93 and 92 is incident on the right-angle prism 96, and the optical axis of the component of wavelength λ1 emitted from the right-angle prism 96 is made to coincide with the optical axis of the laser light output from the front mirror 16. The prism is placed on. With this configuration, the optical axis of the laser chamber and the optical axis of the monitor module are coaxial with each other. Therefore, even if the monitor module equipped with the wavelength selection device A2 and the normal monitor module are replaced, the alignment is re-established. No need to adjust. Further, since the optical axis does not change even if the wavelength selection device A2 is installed or removed, it is possible to easily switch between free run and line select. In this laser device, the rotating stage 94 is rotated from the controller 8 by using the rotating stage driver 79, and the dispersion prism 93 is rotated.
The wavelength can be selected by controlling the angle of the optical axis, and the optical axis can be adjusted by rotating the rotary stage 97 to control the angle of the rectangular prism 96.

Next, an exposure apparatus according to one embodiment of the present invention will be described with reference to FIG. This exposure apparatus performs exposure using the laser device shown in FIG. Figure 1
The exposure apparatus shown in FIG. 6 includes the laser apparatus 400 shown in FIG.
It includes an exposure device 301 and a shutter 411 arranged in an optical transmission path between the laser device 400 and the exposure device 301.
The controller 8 of the laser device 400 generates an abnormal signal when the extinction ratio exceeds the specification value of the exposure device. on the other hand,
The exposure device 301 includes an exposure device controller 302 for controlling optical elements inside the exposure device based on the abnormal signal.
Are arranged. Further, when the emission of the laser beam to the exposure unit is not desired, the controller 8 of the laser device 400 sends a signal to the shutter 411 to close the shutter. Although the laser device and the exposure device shown in FIG. 1 are combined here, the laser device and the exposure device shown in FIG. 13 may be combined.

Next, a control method in the laser device according to the first embodiment of the present invention will be described. Figure 17
6 is a flowchart showing an example of a method for controlling the wavelength selection device based on the measurement result of the spectral intensity of output light in the laser device shown in FIG. 1. In the wavelength selection device shown in FIG. 6, the attitude angle of the HR mirror 113 is controlled by the rotary stage, but the attitude angle of the prism 111 or 112 may be controlled.

As shown in FIG. 17, first, step S1
In step S2, laser oscillation is started, and it is checked in step S2 whether or not the number of shots has reached the specified number of shots. When the number of shots reaches the specified number of shots, the power lock is released (step S3), and the intensity I _{1 of the} λ1 component and the intensity I _{2 of the} λ2 component incident on the wavelength sensor at that time are measured (step S4). . In step S5, the extinction ratio R = I ₂ / I ₁ is calculated from the measurement result.
In step S6, it is checked whether the extinction ratio R exceeds a predetermined upper limit value R (UL). If the extinction ratio R is less than or equal to the upper limit R (UL), the process returns to step S2. On the other hand, when the extinction ratio R exceeds the upper limit R (UR), the process proceeds to step S7 of the subroutine * 1.

In step S7 of the subroutine * 1, it is determined whether the wavelength selection device corresponds to A, which is a prism, grating, or transmission type etalon, B, which is a rear mirror etalon, and C, which is a birefringent filter. , Depending on the result, move to each step.

If the result is A in step S7, the process proceeds to step S8, and the attitude angle in the dispersion direction of the HR mirror, grating, or transmission etalon on the rotary stage is rotated in the positive direction by the angle Δθ. Further, the process proceeds to step S11, and it is checked whether the extinction ratio R has decreased. If the extinction ratio R has decreased, the process proceeds to step S12 to check whether the extinction ratio R has become equal to or lower than the upper limit value R (UL).
If the extinction ratio R is not less than or equal to the upper limit R (UL), the process returns to step S8 and the posture angle is rotated forward (rotated in the same direction as the previous time). Extinction ratio R is the upper limit R
If it becomes less than (UL), the process returns to step S2.

When the extinction ratio R is increased in step S11, the process proceeds to the subroutine * 2, and step S1
In 3, the attitude angle of the HR mirror, the grating or the transmission etalon is reversely rotated by Δθ (rotation in the opposite direction to the previous time), and then in step S16, it is checked whether the extinction ratio R has decreased. If the extinction ratio R has decreased, the process proceeds to step S17, where the extinction ratio R is the upper limit value R (UL).
Check if: The extinction ratio R is the upper limit value R (U
If it exceeds L), the process returns to S13, and step S
The operations of 13 to S17 are repeated. If the extinction ratio R has not decreased in step S16, step S1
Move to 8 and replace the gas with a new one.

If the result of step S7 is B, the process proceeds to step S9. In step S9,
Gas is injected into the inside of the housing including the rear-mirror etalon by ΔP. Further, the process proceeds to step S11, and it is checked whether the extinction ratio R has decreased. If the extinction ratio R has decreased, the process proceeds to step S12 to check whether the extinction ratio R has become equal to or lower than the upper limit value R (UL). If the extinction ratio R is not lower than the upper limit R (UL), the process returns to step S9 and the gas is changed to ΔP.
Repeat the injection procedure. Extinction ratio R is the upper limit value R (UL)
If the following occurs, the process returns to step S2.

When the extinction ratio R is increased in step S11, the process proceeds to the subroutine * 2, and step S1
4, the gas of the housing including the rear-mirror etalon is Δ
After evacuating P, it is checked in step S16 whether the extinction ratio R has decreased. When R decreases, the process proceeds to step S17, and it is checked whether the extinction ratio R is equal to or less than the upper limit value R (UL). If the extinction ratio R exceeds the upper limit R (UL), the process returns to step S14 and the operations of steps S14 to S17 are repeated. If the extinction ratio R has not decreased in step S16, the process proceeds to step S18, and the gas is replaced with a new gas.

If C is satisfied in step S7, the process proceeds to step S10. In step S10, the birefringent filter on the moving stage is moved by ΔL in the positive direction. Further, the process proceeds to step S11, and it is checked whether the extinction ratio R has decreased. If the extinction ratio R has decreased, the process proceeds to step S12 to check whether the extinction ratio R has become equal to or lower than the upper limit value R (UL). The extinction ratio R is the upper limit value R (U
If not less than L), the process returns to step S10, and the process of moving the birefringent filter by ΔL in the same direction as the previous time is repeated. When the extinction ratio R becomes less than or equal to the upper limit value R (UL), the process returns to step S2.

When the extinction ratio R is increased in step S11, the process proceeds to the subroutine * 2, and step S
In 15, the birefringent filter is moved backward by ΔL (moved in the opposite direction to the previous one), and then in step S16, it is checked whether the extinction ratio R has decreased. When R decreases, the process proceeds to step S17, and it is checked whether the extinction ratio R is equal to or less than the upper limit value R (UL). If the extinction ratio R exceeds the upper limit R (UL), the process returns to step S15 and the operations of steps S15 to S17 are repeated. If the extinction ratio R has not decreased in step S16, the process proceeds to step S18, and the gas is replaced with a new gas.

FIG. 18 is a flow chart showing an example of a method for controlling the F ₂ gas concentration in the laser gas based on the measurement result of the spectral intensity of the output light in the laser device shown in FIG. Here, the applied voltage of the high-voltage power supply and the laser gas pressure are measured, and the extinction ratio R is controlled so as to be equal to or less than the upper limit value based on the measurement result and the detection result by the wavelength monitor.

First, laser oscillation is started in step S21, and it is checked in step S22 whether or not the number of shots has reached the specified number of shots. When the number of shots reaches the specified number of shots, the power lock is released (step S23), and the intensity I _{1 of the} λ1 component and the intensity I _{2 of the} λ2 component incident on the wavelength sensor at that time are measured (step S24). . In step S25, the extinction ratio R = I ₂ / I ₁ is calculated from the measurement result. Step S2
6, the extinction ratio R has a predetermined upper limit value R (U
L) is checked. If the extinction ratio R is less than or equal to the upper limit value R (UL), the process returns to step S22. On the other hand, when the extinction ratio R exceeds the upper limit value R (UR), the process proceeds to step S27, and the applied voltage V and the gas pressure P are measured.

In step S28, the F ₂ gas concentration C _F is calculated based on the applied voltage V, the gas pressure P and the extinction ratio R. In this calculation, the characteristics shown in FIG. 2 are used. Further, in step S29, with the applied voltage V and the gas pressure P kept constant, the target F ₂ gas concentration C _F (T) for making the extinction ratio R below the upper limit R (UL) is obtained. . In step S201, it is checked whether C _F is larger than C _F (T).

If C _F is larger than C _F (T), the process proceeds to step S202, in which a part of the laser gas (pressure ΔP) is exhausted in order to reduce the F ₂ gas concentration in the laser gas. _The buffer gas containing no ₂ gas is injected by the same pressure (ΔP), and the process returns to step S22. On the other hand, C
_{If F} is C _F (T) or less, the extinction ratio R cannot be decreased even if the F ₂ gas concentration is further decreased.
Gas exchange is performed at 03.

FIG. 19 is a flow chart showing another example of the method for controlling the F ₂ gas concentration in the laser gas based on the measurement result of the spectral intensity of the output light in the laser device shown in FIG. Here, after the gas control, the light intensity of each wavelength is measured again to determine whether the value of the extinction ratio R has decreased.

First, laser oscillation is started in step S31, and it is checked in step S32 whether or not the number of shots has reached the specified number of shots. When the number of shots reaches the specified number of shots, the power lock is released (step S33), and the intensity I _{1 of the} λ1 component and the intensity I _{2 of the} λ2 component incident on the wavelength sensor at that time are measured (step S34). . In step S35, the extinction ratio R = I ₂ / I ₁ is calculated from the measurement result. Step S3
6, the extinction ratio R has a predetermined upper limit value R (U
L) is checked. If the extinction ratio R is less than or equal to the upper limit value R (UL), the process returns to step S32. On the other hand, when the extinction ratio R exceeds the upper limit R (UR), the process proceeds to step S37, and the applied voltage V and the gas pressure P are measured.

In step S38, the F ₂ gas concentration C _F is calculated based on the applied voltage V, the gas pressure P and the extinction ratio R. In this calculation, the characteristics shown in FIG. 2 are used. Further, in step S39, the target F ₂ gas concentration C _F (T) for making the extinction ratio R equal to or less than the upper limit value R (UL) is obtained with the applied voltage V and the gas pressure P kept constant. . In step S40,
Check if C _F is greater than C _F (T).

If C _F is larger than C _F (T), the process proceeds to step S41, and in order to reduce the concentration of F ₂ gas in the laser gas, while exhausting part of the laser gas (pressure ΔP), ₂ Inject the buffer gas containing no gas at the same pressure (ΔP). On the other hand, when C _F is C _F (T) or less, the extinction ratio R cannot be decreased even if the F ₂ gas concentration is further decreased. Gas exchange is performed in S46.

After the gas control in step S41, the intensity I _{1 of the} λ1 component and the intensity I _{2 of the} λ2 component incident on the wavelength sensor are measured again in step S42. Further, in step S43, it is checked whether the extinction ratio R has decreased, and if it has decreased, the process proceeds to step S44.
It is checked whether the extinction ratio R is less than or equal to the upper limit value R (UL). If the extinction ratio R is less than or equal to the upper limit value, step S
Return to 32. When the extinction ratio R is larger than the upper limit value, the process proceeds to step S45, and the F ₂ gas concentration C _F is the lower limit value C.
Check if it is larger than _F (LL). If C _F is larger than the lower limit value, the operation of decreasing the F ₂ gas concentration after step S37 is repeated.

If the extinction ratio R has not decreased in step S43, the process proceeds to step S47, and the gas is replaced with a new one. Further, in step S45, F ₂
If the gas concentration C _F is less than or equal to the lower limit C _F (LL), the process proceeds to step S48 and the gas is replaced with a new one.

FIG. 20 is a flowchart showing a control method combining the control methods of FIGS. 17 and 19 in the laser device shown in FIG. First, after measuring the spectral intensity of the selected wavelength and controlling the wavelength selection device based on the measurement result, if the extinction ratio cannot be lowered by the control of the wavelength selection device, the control of the F ₂ gas concentration is performed. Carry out.

As shown in FIG. 20, when the extinction ratio R does not decrease in step S16, the gas exchange is not performed, but the operation proceeds to the operation of decreasing the F ₂ gas concentration after step S37. After the gas control in step S41, in step S42, the λ incident on the wavelength sensor
The intensity I _{1 of the one} component and the intensity I _{2 of the} λ2 component are measured again. Further, in step S43, it is checked whether or not the extinction ratio R has decreased. If the extinction ratio R is equal to or less than the upper limit value R (UL) in step S44, the process returns to step S2. Such control has the effect of substantially extending the life of the laser gas.

FIG. 21 is a control timing chart in the laser device shown in FIG. 1, in which the horizontal axis represents the number of shots. In FIG. 21, (a) is a graph showing the relationship between the λ2 extinction ratio and the number of shots, (b) is a graph showing the adjustment timing of the optical element, and (c) is the adjustment timing of the F ₂ gas partial pressure. It is a graph which shows. As shown in FIG. 21, when the λ2 extinction ratio approaches the upper limit value, adjustment is first performed by the optical element, and only λ2 is adjusted by the optical element.
2 When it becomes impossible to lower the extinction ratio, the adjustment by the partial pressure of F ₂ gas is also used. Here, the λ2 extinction ratio is controlled by the attitude control of the optical element used in the wavelength selection device and the F ₂ gas concentration, but other than that, it may be controlled by the total gas pressure or the applied voltage.

[0078]

As described above, according to the present invention,
Since the intensity of the λ1 component, the intensity of the λ2 component, etc. can be measured by the wavelength sensor, it is possible to use such information to provide a laser device that can be easily controlled to reduce the wavelength components that are not selected. You can Furthermore, it is possible to provide an exposure apparatus using such a laser device.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a laser device according to a first embodiment of the present invention.

FIG. 2 is a graph showing the dependence of the λ2 extinction ratio on the partial pressure of F ₂ gas.

FIG. 3 is a graph showing the dependence of λ2 extinction ratio on total gas pressure.

FIG. 4 is a graph showing the output energy dependence of the λ2 extinction ratio.

FIG. 5 is a graph showing the dependence of λ2 extinction ratio on the partial pressure of F ₂ gas under a constant output condition.

FIG. 6 is a diagram showing a first specific example of the wavelength selection device used in the first embodiment of the present invention.

FIG. 7 is a diagram showing a second specific example of the wavelength selection device used in the first embodiment of the present invention.

FIG. 8A is a diagram showing a third specific example of the wavelength selection device used in the first embodiment of the present invention,
(B) is a figure showing the 4th example.

FIG. 9 is a diagram showing a fifth specific example of the wavelength selection device used in the first embodiment of the present invention.

FIG. 10 is a diagram showing a first specific example of a monitor module used in the first embodiment of the present invention.

FIG. 11 is a diagram showing a second specific example of the monitor module used in the first embodiment of the present invention.

FIG. 12 is a graph showing how the λ2 extinction ratio changes with respect to the total number of shots.

FIG. 13 is a diagram showing a configuration of a laser device according to a second embodiment of the present invention.

FIG. 14 is a diagram showing a first specific example of the wavelength selection device used in the second embodiment of the present invention.

FIG. 15 is a diagram showing a second specific example of the wavelength selection device used in the second embodiment of the present invention.

FIG. 16 is a diagram showing a configuration of an exposure apparatus that performs exposure using the laser apparatus according to the first embodiment of the present invention.

FIG. 17 is a flowchart showing an example of a method for controlling the wavelength selection device based on the measurement result of the spectral intensity of output light in the laser device according to the first embodiment of the present invention.

FIG. 18 is a flowchart showing an example of a method for controlling the F ₂ gas concentration in the laser gas based on the measurement result of the spectral intensity of output light in the laser device according to the first embodiment of the present invention.

FIG. 19 is a flowchart showing another example of the method for controlling the F ₂ gas concentration in the laser gas based on the measurement result of the spectral intensity of output light in the laser device according to the first embodiment of the present invention.

FIG. 20 is a flowchart showing a control method in which the control methods of FIGS. 17 and 19 are combined in the laser device according to the first embodiment of the present invention.

FIG. 21 is a control timing chart in the laser device according to the first embodiment of the present invention.

FIG. 22 is a diagram showing a configuration of a conventional laser device.

FIG. 23 is a diagram showing typical wavelength components output in a free-run F ₂ laser device.

FIG. 24 is a diagram showing a λ1 component and a λ2 component output in a line select F ₂ laser device.

[Explanation of symbols]

1 laser chamber 2, 3 window 4, 200 monitor module 5, 205 beam splitter 6 ASE monitor 7 energy monitor 8 controller 9 gas controller 10 rear optical module 11 power supply 12 discharge electrode 15, 30 spatial filter (slit) 16 front mirror 51, 52, 92, 93, 111, 112 Dispersion prism 53, 152 Total reflection mirror 55 Constant temperature bath 56, 57 Window 91, 95, 96 Right angle prism 94, 97, 114, 124, 132 Rotation stage 100-105, 110, A1, A2 Wavelength selection device 113, 133, 163 HR mirrors 121, 122 Beam expander prism 123 Grating 131 Transmission type etalon 141 Rear mirror etalon 151 Birefringence filter 153 Moving stage 210 Wave Sensor 220 the energy monitor 231, 241 diffusing plate 232 etalons 234 and 242 condenser lenses 235,248 line sensor 243 slits 244, 245 concave mirror 246 mirror 247 grating 301 exposure 302 exposure unit controller 400 laser device 411 Shutter

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H097 AA03 CA13 LA10                 5F046 CA03 CA07                 5F071 AA04 DD04 HH01 HH02 HH05                       JJ05                 5F072 AA04 HH01 HH02 HH05 JJ05                       KK01 KK05 KK08 KK15 KK30                       YY09

Claims (17)

[Claims] 1. A laser chamber including a laser chamber filled with a laser gas and a discharge electrode for exciting and activating the laser gas, and generating laser light having at least a first wavelength component and a second wavelength component. A laser resonator, a wavelength selecting unit that is disposed inside the laser resonator and mainly generates a first wavelength component in the laser resonator, and a gas controller that adjusts a laser gas with which the laser chamber is filled. A power supply unit that applies a voltage to the discharge electrode, a detection unit that detects the intensity of laser light output from the laser resonator for a plurality of wavelength components, and at least a first wavelength component detected by the detection unit. At least one of the wavelength selecting unit, the gas controller, and the power supply unit based on the intensity and the intensity of the second wavelength component. Laser apparatus comprising a control means for controlling, the. 2. The laser resonator generates laser light containing an amplified spontaneous emission (ASE) component.
The laser device described. 3. A laser chamber filled with a laser gas, and a discharge electrode for exciting and activating the laser gas to generate laser light having at least a first wavelength component and a second wavelength component. And a wavelength selection for emitting the first wavelength component and the second wavelength component included in the laser light generated by the laser resonator in different directions. Means, a gas controller for adjusting the laser gas filled in the laser chamber, a power supply unit for applying a voltage to the discharge electrode, and an intensity of laser light output from the laser resonator via the wavelength selection unit. Detecting means for detecting a plurality of wavelength components, and based on at least the intensity of the first wavelength component and the intensity of the second wavelength component detected by the detecting means. Laser apparatus comprising a control means for controlling at least one of said wavelength selection means and the gas controller and the power supply unit. 4. The laser device according to claim 3, further comprising a spatial filter that cuts a second wavelength component from the laser light output from the laser resonator via the wavelength selecting means. Wherein said control means, based on the first intensity Airamuda _first wavelength component and intensity Airamuda ₂ of the second wavelength component detected by said detecting means, the extinction ratio of the second wavelength component Airamuda ₂ / (Iλ ₁ + Iλ ₂ ) or Iλ ₂ / Iλ ₁ is controlled to be 0.1% or less, and at least one of the wavelength selecting means, the gas controller, and the power supply unit is controlled.
The laser device according to claim 1. 6. The detector according to claim 1, wherein the detecting means includes an etalon spectroscope or a grating spectroscope.
The laser device according to the item. 7. The laser device according to claim 1, wherein the wavelength selection unit includes a dispersion prism, a grating, an etalon, or a birefringence filter. 8. The laser device according to claim 1, wherein the control unit controls the attitude angle or pressure or position of at least one optical element included in the wavelength selection unit. 9. The laser device uses F 2 as a laser gas.
9. The laser device according to claim 1, which is an F ₂ laser using a mixed gas of ₂ (fluorine molecule) gas and a buffer gas. 10. The laser apparatus according to claim 9, wherein the control unit controls the gas controller to change a partial pressure of F ₂ gas in the laser chamber. 11. The gas controller changes the partial pressure of F ₂ gas by simultaneously injecting a buffer gas or a halogen gas and exhausting a mixed gas.
0 laser device. 12. The control means controls the gas controller such that the partial pressure of F ₂ gas in the laser chamber is 0.28 kPa or less or the F ₂ gas concentration is 0.11% or less. The laser device according to any one of claims 9 to 11. 13. The control means controls the gas controller so that the partial pressure of F ₂ gas in the laser chamber is 0.26 kPa or less, or the F ₂ gas concentration is 0.09% or less. The laser device according to any one of claims 9 to 11. 14. The laser device according to claim 1, wherein the control unit controls the gas controller so as to change the pressure of the laser gas in the laser chamber. 15. An exposure apparatus comprising: the laser device according to claim 1; and an exposure device that exposes an object using a laser beam generated by the laser device. 16. A shutter disposed between the laser device and the exposure device, wherein the control means controls the intensity of at least the first wavelength component and the second wavelength detected by the detection means. The exposure apparatus according to claim 15, wherein opening and closing of the shutter is controlled based on the intensity of the component. 17. The method of claim 16, wherein the control means, based on the first intensity Airamuda _first wavelength component and intensity Airamuda ₂ of the second wavelength component detected by said detecting means, the extinction ratio of the second wavelength component Airamuda The exposure apparatus according to claim 16, wherein the shutter is controlled to be closed when ₂ / (Iλ ₁ + Iλ ₂ ) or Iλ ₂ / Iλ ₁ becomes equal to or more than a predetermined value.