JP3831796B2 - Gas control device for laser equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas control device for a laser device such as an excimer laser in which the laser output is reduced due to a decrease in the gas concentration of a part of the gas constituting the laser gas accompanying laser oscillation. The present invention relates to a gas control apparatus for a laser apparatus that can appropriately control injection and exhaust of laser gas during continuous laser oscillation without affecting the laser.
[0002]
[Prior art]
Conventionally, a laser gas used by an excimer laser is a mixed gas of a halogen gas, a rare gas, and a buffer gas. For example, in the case of a KrF excimer laser, a mixed gas of F2, Kr, and Ne is used, and in the case of an ArF excimer laser Uses a mixed gas of F2, Ar, and Ne.
[0003]
In this excimer laser, when the laser oscillation is continued, the laser output is decreased mainly by the combination of the electrode material and the halogen gas and the generation of the compound thereof due to the decrease of the halogen gas and the increase of dust (impurity gas) in the laser gas. On the other hand, when the halogen gas concentration is increased, the laser output increases. The laser output also rises and falls as the laser excitation power supply voltage rises and falls.
[0004]
Thus, for example, US Pat. No. 4,977,573 describes an excimer laser output control device, which obtains a constant laser output by increasing the power supply voltage of the laser output that decreases with laser oscillation, and supplies the power supply voltage. When the rise limit is reached, a halogen gas is injected into the laser chamber, and the laser output is increased by this injection. Therefore, a control for lowering the power supply voltage is performed to obtain a constant laser output. Further, when necessary, the laser gas in the laser chamber is exhausted before and after the halogen injection, and the above-mentioned dust is removed and refreshed, so that a constant stable output can be maintained for a relatively long time.
[0005]
That is, FIG. 6 shows the relationship between the time based on the gas control in the gas control device of the conventional laser device and the power supply voltage. In FIG. 6, the halogen gas decreases with the passage of time due to laser oscillation. Since the laser output is reduced, the power supply voltage is raised so as to obtain a constant laser output, but the power supply voltage is within the control range within the power supply voltage range E10 that can be controlled to a constant laser output. The halogen gas is injected at timings T1 to T4 when the upper limit is reached. Since the laser output is increased by the halogen gas injection, the power supply voltage is controlled to decrease. Further, when the laser output does not increase greatly even when the halogen gas is injected as in the vicinity of the timing T4, the laser gas in the laser chamber is exhausted before and after the timing T4 to refresh the laser gas. Yes.
[0006]
[Problems to be solved by the invention]
However, the conventional gas control apparatus described above has a problem in that the halogen gas is rapidly injected into the laser chamber, so that the gas flow in the laser chamber is disturbed and the laser output becomes transiently unstable. . In particular, immediately after the halogen gas is injected at the timings T1 to T4 in FIG. 6, the control of the power supply voltage is performed rapidly. Therefore, even if the laser output can be kept constant, the laser wavelength can be controlled. There was a problem that there were cases where it was impossible to follow.
[0007]
Further, since the laser gas is exhausted immediately before or after the timing T4 when the halogen gas is injected, if the power supply voltage tends to increase in the vicinity of the upper limit of the power supply voltage, control for further increasing the power supply voltage by this exhaust processing is performed. As a result, there is a problem that the power supply voltage exceeds the control range and becomes uncontrollable.
[0008]
Furthermore, since the laser gas is exhausted after the halogen gas is injected, there is a high possibility that the injected halogen gas is exhausted as it is, and the halogen gas is not effectively used. There was a problem that it could not be done.
[0009]
On the other hand, a laser apparatus such as an excimer laser is desired to be capable of continuous laser oscillation over a long period of time without gas exchange that requires laser oscillation to stop or unstable laser oscillation.
[0010]
Therefore, the present invention eliminates such problems, performs a laser gas exchange process without stopping laser oscillation or causing unstable laser oscillation, and enables a laser apparatus capable of continuous laser oscillation over a long period of time. An object is to provide a gas control device.
[0011]
[Means for solving the problems and effects]
According to a first aspect of the present invention, there is provided a first injection means for injecting a halogen gas into a laser chamber so as to keep the concentration of the halogen gas substantially constant with respect to the concentration of the total mixed gas, and a mixed gas of a rare gas and a buffer gas. A second injection means for injecting into the laser chamber; a detection means for detecting a supply voltage to the laser from a laser excitation power supply; and an exhaust means for exhausting a gas in the laser chamber. In the gas control device of the laser device that controls the output to detect and feed back the laser output, the injection mode and the exhaust mode are alternately performed. In the injection mode, the laser output is The first injection means for replenishing the halogen gas in the laser chamber within a range capable of following the control to achieve the constant stable output and the wavelength control. In order to increase the injection amount of the halogen gas and the total gas pressure in the laser chamber, the injection amount of the mixed gas of the rare gas and the buffer gas from the second injection means is controlled. the supply voltage detected by said detecting means to keep raised the laser output constant and stable output performs control to reduce in association with the injection quantity, in the exhaust mode, the laser output is to the constant and stable output The amount of gas exhausted from the laser chamber by the exhaust means is controlled within a range that can follow control and wavelength control, and the laser output that is lowered by the exhaust of the gas is detected by the detection means so as to maintain a constant stable output. performs control to increase in correspondence to the exhaust amount supply voltage that is, whether the injection mode when the supply voltage reaches the first voltage drops The switched to exhaust mode, and wherein said switching from the exhaust mode to the injection mode when the supply voltage reaches a second higher voltage than the first voltage rises.
[0012]
In the first invention, the injection of the halogen gas, the rare gas, and the buffer gas and the exhaust of the gas in the laser chamber can be performed without affecting the control of the constant laser output and the wavelength control. Since a part of the gas can be exchanged, a constant laser output can be obtained for a long time. Moreover, since the injection mode and the exhaust mode are controlled separately, the injected halogen gas or the like is not immediately exhausted, so that the gas exchange in the laser chamber is performed efficiently.
[0013]
The second invention according to the first invention, in the injection mode, controls the injection amount so that the supply voltage is continuously and gradually decreased, and in the exhaust mode, the supply voltage is continuously and slowly The exhaust amount is controlled so as to rise to a large value.
[0014]
In the second invention, since the injection amount or the exhaust amount is controlled so that the supply voltage continuously and gradually decreases, a constant laser output can be stably obtained.
[0015]
A third invention is characterized in that, in the first or second invention, the laser output is controlled within a supply voltage range in which control of keeping the laser output at a constant stable output is possible.
[0016]
In the third aspect of the invention, since the control is performed within the supply voltage range in which the laser output can be controlled to be a constant stable output, the control can be reliably performed.
[0017]
According to a fourth invention, in the first to third inventions, the laser output is switched from the exhaust mode to the injection mode at an upper limit supply voltage within a range in which the laser output can be controlled to be a constant stable output. The injection mode is switched to the exhaust mode at a lower limit supply voltage within a range capable of controlling to maintain a constant stable output.
[0018]
In the fourth invention, since the injection mode and the exhaust mode are switched when the upper limit supply voltage or the lower limit supply voltage is reached, the number of times of switching between the injection mode and the exhaust mode can be reduced. Halogen gas is effectively used.
[0019]
According to a fifth invention, in the fourth invention, the upper limit supply voltage is a value lower by a predetermined amount than the upper limit supply voltage, and the lower limit supply voltage is a value higher by a predetermined amount than the lower limit supply voltage. .
[0020]
As a result, a predetermined margin is provided, so that reliable control can be performed without runaway control.
[0021]
According to a sixth invention, in the first to fifth inventions, the injection amount and the exhaust amount are controlled in accordance with the number of laser oscillation pulses.
[0022]
In the sixth invention, attention is paid to the fact that halogen gas is consumed with laser oscillation, and the injection amount and exhaust amount are controlled in accordance with the number of laser oscillation pulses. It can be controlled as a quantity.
[0023]
A seventh aspect of the sixth invention from the first, the starts controlling the injection mode, further, the laser chamber, characterized in that the laser gas having a mixing ratio of the best before laser oscillation is filled And
[0024]
Thereby, since the laser gas having the optimal mixing ratio is not exhausted at the beginning, the filled laser gas can be used effectively.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0026]
FIG. 1 is a diagram showing a configuration of an excimer laser equipped with a gas control apparatus according to an embodiment of the present invention.
[0027]
In FIG. 1, the excimer laser 1 has a discharge electrode or the like not shown in the laser chamber 2, and Kr, A laser gas composed of a mixed gas of F2 and Ne is excited and laser oscillation is performed. The emitted light is narrowed by the band narrowing unit 3, is returned to the laser chamber 2 again, is amplified, and is output as the oscillation laser light L through the front mirror 4.
[0028]
The laser power source 5 gives a potential difference between the discharge electrodes based on the voltage data sent from the control unit 9 to cause pulse discharge. The laser power source 5 temporarily stores charges by a charging circuit (not shown), and then performs pulse discharge by the operation of a switching element such as a GTO or a thyristor.
[0029]
A part of the laser light L oscillated from the resonator composed of the front mirror 4, the laser chamber 2, and the band narrowing unit 3 is sampled by the beam splitter 10 and enters the optical monitor module 12 via the lens 11. Is done. The remaining laser light L is emitted to an exposure device (not shown) and used.
[0030]
Each time pulse oscillation is performed, the optical monitor module 12 detects the energy per pulse of the output laser light L, and this detected pulse energy value is sent to the control unit 9. Further, the optical monitor module 12 detects interference fringes between a reference light (not shown) and the monitored laser light L, and sends the detection result to the control unit 9. The optical monitor module 12 performs detection of pulse energy and interference fringes by the same module, but may be performed by separate modules.
[0031]
Based on the detected pulse energy value sent from the optical monitor module 12, the control unit 9 feedback-controls the power supply voltage supplied to the discharge electrode via the laser power supply 5 so that a constant laser output is obtained. The wavelength control unit 9a in the control unit 9 calculates a wavelength shift based on the interference fringes transmitted from the optical monitor module 12, and performs feedback control via the band narrowing module 3 so as to eliminate this wavelength shift. To do. That is, the wavelength control is performed so that the laser light L having a desired wavelength oscillates by performing control such as rotating a wavelength selection element such as a grating in the band narrowing unit 3.
[0032]
The laser chamber 2 is initially filled with a mixed gas composed of Kr, F2, and Ne having the most appropriate mixing ratio for laser oscillation, but the halogen gas (F2) decreases with the number of laser pulse oscillations. In the injection mode, a ternary gas 6 composed of Kr, F2, and Ne is injected into the laser chamber 2 through the plug 6a in order to cause a phenomenon in which the laser output is reduced under a constant power supply voltage. A binary gas 7 made of Kr and Ne is injected through 7a.
[0033]
In the exhaust mode, the laser gas in the laser chamber 2 is exhausted by the exhaust device 8 through the plug 8a.
[0034]
These injection and exhaust processes are controlled by the control unit 9, and this control is performed by opening / closing control of the plugs 6a, 7a, 8a by the gas injection / exhaust control unit 9b.
[0035]
As described above, the control unit 9 performs control so that a constant laser output having a constant wavelength is stably output. In particular, in the constant laser output control, the laser output is filled in the laser chamber 2. This is based on being a function of the three factors of the total gas pressure, the halogen gas pressure, and the power supply voltage. Here, the laser output increases as the total gas pressure increases, increases as the halogen gas pressure increases, and increases as the power supply voltage increases. Therefore, when controlling to a constant laser output, for example, when the halogen gas pressure is constant and the total gas pressure increases, the power supply voltage may be decreased, and conversely when the total gas pressure decreases. The power supply voltage may be increased.
[0036]
Therefore, in order to keep the laser output constant, the control unit 9 basically increases the power supply voltage when the detected pulse energy value from the optical monitor module 12 is lower than the desired value. If the detected pulse energy value is higher than the desired value, the power supply voltage is basically reduced, but the laser output decreases as the number of laser pulse oscillations increases. Therefore, as control with a large period, control for increasing the total gas pressure and the halogen gas pressure is performed, and in order to compensate for the increase in laser output due to this control, control for lowering the power supply voltage is performed, and in the laser chamber 2 Control of increasing the power supply voltage is performed because the total gas pressure and the halogen gas pressure are reduced by evacuating the laser gas, and the laser output is reduced.
[0037]
That is, the control unit 9 controls the injection and exhaust of the halogen gas, the rare gas, and the buffer gas with a large cycle.
[0038]
For example, if 100% halogen gas can be used, the halogen gas injection amount Gh in the injection mode is:
Gh = (halogen gas consumption + target value × optimum halogen gas concentration) × laser pulse oscillation number,
The injection amount Gr of the mixed gas of the rare gas (Kr) and the buffer gas (Ne) is
Gr = target value × (1−optimum halogen gas concentration) × laser pulse oscillation number. Here, the target value is an amount sufficient to reduce the power supply voltage. For this reason, when the amount of decrease in the power supply voltage is reduced, the target value is reduced, and the final injection amounts Gh and Gr are reduced. Here, the injection amounts Gh and Gr are controlled according to the number of laser pulse oscillations. This is because the halogen gas consumption, that is, the decrease in halogen gas increases and the dust increases with the number of laser pulse oscillations. Thereby, the concentration of the halogen gas with respect to the concentration of the rare gas and the buffer gas in the laser chamber 2 can be controlled to the optimum halogen gas concentration (Gh / Gr = 0.15%).
[0039]
However, since it is difficult at this stage to make a high-purity gas consisting only of halogen gas and it is not desirable from the viewpoint of storage, a ternary gas 6 composed of Kr, F2, and Ne and a binary gas 7 composed of Kr, Ne and Is injected into the laser chamber 2 to increase the total gas pressure and the halogen gas pressure, and by exhausting the laser gas in the laser chamber 2, the total gas pressure and the halogen gas pressure are decreased.
[0040]
Actually, the ternary gas 6 has a mixing ratio of F2: Kr: Ne = 1%: 1.25%: 97.75%, and the binary gas 7 has a mixing ratio of Kr: Ne =. 1.25%: 98.75%. Even when the ternary gas 6 and the binary gas 7 are used, the above-described injection amount can be controlled by correcting the amounts of the rare gas and the buffer gas in the ternary gas 6. That is, the injection amount Gh ′ of the ternary gas 6 is
Gh ′ = Gh / halogen cylinder concentration binary gas 7 injection amount Gr ′ is:
Gr ′ = Gr−Gh ′ × (1-halogen cylinder concentration)
Then, the halogen gas concentration in the laser chamber 2 is
Gh ′ × halogen cylinder concentration / (Gr ′ + Gh ′) = Gh / Gr, which is the optimum halogen gas concentration.
[0041]
Therefore, even if the ternary gas 6 and the binary gas 7 are used, the injection amount of only the halogen gas and the injection amount of only the mixed gas composed of the rare gas and the buffer gas can be controlled. In other words, even if the cylinder concentration changes, the same control can be performed simply by entering a set value.
[0042]
Next, gas injection / exhaust control by the control unit 9 and power supply voltage control associated therewith will be described.
[0043]
FIG. 2 is a diagram illustrating changes in the power supply voltage and the gas pressure in the laser chamber 2 with respect to the number of laser oscillation pulses by the control unit 9.
[0044]
In FIG. 2A, an optimum laser gas is initially filled in the laser chamber 2 at the beginning of laser oscillation, and halogen gas is consumed as the number of laser oscillation pulses increases. Decrease. Therefore, at the beginning, that is, from the number of laser oscillation pulses N0 to N1, the injection mode is set, and the above-described mixed gas composed of the halogen gas, the rare gas, and the buffer gas is supplied into the laser chamber 2. With this gas injection, the total gas pressure gradually increases (FIG. 2B, and the laser output increases, so the control unit 9 performs a process of gradually decreasing the power supply voltage (FIG. 2A). As a result, a constant laser output can be stably obtained in the injection mode m 1. Although the control unit 9 also performs wavelength control by the wavelength control unit 9a, the control unit 9 performs constant laser output control and wavelength control. An appropriate injection amount is controlled by appropriately setting a fluctuation of the power supply voltage that does not affect the control, that is, a target value.
[0045]
On the other hand, in the injection mode m1, the power supply voltage gradually decreases, but when the power supply voltage reaches Vmin, the control unit 9 is switched to the exhaust mode m2. By this switching, the control unit 9 stops the injection of the halogen gas, the rare gas, and the buffer gas, and gradually exhausts the laser gas in the laser chamber 2 by the exhaust device 8. This evacuation needs to be performed to the extent that it does not affect the constant laser output control and wavelength control, similar to the injection. That is, the exhaust amount is controlled so that the laser gas in the laser chamber 2 is exhausted so as not to cause a non-uniform pressure state or pulsation. This exhaust amount is gradually exhausted according to the number of laser oscillation pulses as in the injection mode m1. Then, when the power supply voltage gradually rises and this power supply voltage reaches Vmax, the control unit 9 switches to the injection mode m3 and executes the same control as in the injection mode m1. When the gas is gradually exhausted, halogen gas injection according to the number of laser oscillation pulses may be performed in order to compensate for the halogen gas consumption during the exhaust operation and to make the halogen gas concentration constant.
[0046]
By the way, the range of the power supply voltage capable of such laser output control and wavelength control is a region sandwiched between the maximum power supply voltage VA and the minimum power supply voltage VB shown in FIG. Further, the control unit 9 switches from the exhaust mode to the injection mode at the upper limit power supply voltage Vmax that is a predetermined amount smaller than the maximum power supply voltage VA, and switches from the injection mode to the exhaust mode at the lower limit power supply voltage Vmin that is a predetermined amount larger than the minimum power supply voltage VB. To switch to. For example, when switching from the exhaust mode to the injection mode, the power supply voltage exceeds the maximum power supply voltage VA and becomes uncontrollable due to an increase in the power supply voltage to compensate for the decrease in the total gas pressure due to exhaust. This is to reliably prevent this.
[0047]
FIG. 3 is an enlarged view of a change in power supply voltage in the injection mode m1 of FIG. In FIG. 3, the time points at which the halogen gas, rare gas, and buffer gas are injected into the laser chamber 2 are indicated by P1 to P3. These injection intervals are determined by a preset number of laser oscillation pulses ΔN. Of course, this laser oscillation pulse number ΔN may be determined at any time in accordance with the decrease or increase of the power supply voltage and further in relation to the total number of laser oscillation pulses. Further, the control unit 9 may learn the laser oscillation pulse number ΔN and the above-described injection amount or exhaust amount based on the result of once controlling. Note that ΔN in FIG. 3 is actually performed at intervals of about 30 minutes, and at least laser oscillation of about 20,000 pulses is performed.
[0048]
Here, the above-described injection / exhaust control and power supply voltage control will be described with reference to the flowchart shown in FIG.
[0049]
In FIG. 4, first, the partial pressure ratio of halogen gas: rare gas: buffer gas is appropriate in the laser chamber 2 and the total gas pressure is set to the gas pressure Ps as shown in FIG. 2 (step S1). Further, Vmin is set from Vmax, which is the control range of the power supply voltage, and a gas injection amount ΔG for each laser oscillation pulse number ΔN is set (step S2). At this gas pressure Ps, the power supply voltage for obtaining a desired constant laser output is set to Vmax.
[0050]
Thereafter, when laser oscillation is started (step S3), the controller 9 determines whether or not the number of times of laser oscillation after gas replenishment has reached ΔN in the initial injection mode (step S4), and does not satisfy ΔN. In this case, the process proceeds to step S3 and laser oscillation is continued. When ΔN is reached, the gas of ΔG is supplied from the ternary gas 6 and the binary gas 7 into the laser chamber 2 and the laser output is constant. A process for reducing the power supply voltage is performed (step S5). Thereafter, it is further determined whether or not the power supply voltage has reached Vmin (step S6). If Vmin has not been reached, the process proceeds to step S3 and the above processing is repeated. Transition from injection mode to exhaust mode.
[0051]
In the exhaust mode, the laser gas in the laser chamber 2 is gradually exhausted (injection of the consumed halogen gas as necessary), and the power supply voltage is increased so that the laser output becomes constant (step S7). ). Thereafter, it is determined whether or not the power supply voltage has reached Vmax (step S8). If it has not reached Vmax, the process proceeds to step S7, and the exhaust of the laser gas is continued. The process proceeds to S3, the mode is again switched to the injection mode, and the above-described processing is repeated.
[0052]
In this way, during continuous laser oscillation for a long time, the injection mode and the exhaust mode are switched by the arrival of the power supply voltages Vmax and Vmin, and the halogen gas, the rare gas, and the buffer gas are gradually replenished. The laser gas in the laser chamber 2 is partially exchanged by exhausting.
[0053]
Further, by performing such control, it is possible to suppress the influence of dust to a certain level or less, so in principle, laser oscillation is possible until the life of other parts. A constant and stable laser output can be obtained by continuous pulse oscillation of 10,000 pulses without special laser gas exchange.
[0054]
By the way, in the above-described embodiment, the number of laser oscillation pulses in the injection mode and the exhaust mode is substantially the same, but it is considered that the influence on the change in the laser gas output due to the exhaust in the exhaust mode is small. The rising slope of the power supply voltage due to the exhaust in may be made larger than the falling slope of the power supply voltage in the injection mode.
[0055]
FIG. 5 is a diagram showing changes in the power supply voltage and the total gas pressure when control is performed in which the rising slope of the power supply voltage in the exhaust mode with respect to the number of laser oscillation pulses is made larger than the downward slope in the injection mode. Even if the number of laser oscillation pulses in the exhaust mode is reduced as shown in FIG. 5, the same effect as the above-described embodiment can be obtained, and the number of times of laser gas exchange is increased, so that the refreshing effect of the laser gas is increased. The dust reducing effect in the laser chamber 2 can be increased.
[0056]
Of course, if the number of laser oscillation pulses in the injection mode is made smaller than the number of laser oscillation pulses in the exhaust mode, the same effect as that of the above-described embodiment can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an excimer laser equipped with a gas control apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing changes in a power supply voltage and a gas pressure in a laser chamber with respect to the number of laser oscillation pulses.
FIG. 3 is an enlarged view of a change in power supply voltage with respect to the number of laser oscillation pulses in an injection mode.
FIG. 4 is a flowchart showing a procedure of injection / exhaust control and power supply voltage control.
FIG. 5 is a diagram showing changes in the power supply voltage and the total gas pressure when the rising slope of the power supply voltage in the exhaust mode with respect to the number of laser oscillation pulses is made larger than the falling slope in the medium mode.
FIG. 6 is a diagram showing a relationship between a time based on gas control in a gas control device of a conventional laser apparatus and a power supply voltage.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Excimer laser 2 ... Laser chamber 3 ... Band narrowing unit 4 ... Front mirror 5 ... Laser power supply 6 ... Three-way gas 7 ... Two-way gas 8 ... Exhaust device 6a, 7a, 8a ... Plug 9 ... Control part 9a ... Wavelength Control unit 9b ... Gas injection / exhaust control unit 10 ... Beam splitter 11 ... Lens 12 ... Optical monitor module L ... Laser light m1, m3 ... Injection mode m2 ... Exhaust mode N0-N3 ... Number of laser oscillation pulses Vmax ... Upper limit power supply voltage Vmin ... Lower limit power supply voltage

Claims (7)

First injecting means for injecting the halogen gas into the laser chamber in order to keep the concentration of the halogen gas substantially constant with respect to the concentration of the total mixed gas;
Second injection means for injecting a mixed gas of a rare gas and a buffer gas into the laser chamber;
Detection means for detecting the supply voltage to the laser from the laser excitation power supply;
Exhaust means for exhausting the gas in the laser chamber,
In a gas control device of a laser device that performs control to detect laser output and keep the laser output substantially constant by feeding back the laser output,
Alternate between injection mode and exhaust mode ,
In the injection mode, the halogen gas is supplied from the first injection means so as to replenish the halogen gas in the laser chamber within a range in which the laser output can follow the control to make the constant stable output and the wavelength control. In order to increase the injection amount and the total gas pressure in the laser chamber, the injection amount of the mixed gas of the rare gas and the buffer gas from the second injection means is controlled, and the laser output rising by the injection of these gases is kept constant. In order to keep the stable output of the control means, the supply voltage detected by the detection means is controlled to decrease corresponding to the injection amount,
In the exhaust mode, the exhaust amount of the gas in the laser chamber is controlled by the exhaust means within a range in which the laser output can follow the control to make the constant stable output and the wavelength control, and the laser output is lowered by the exhaust of the gas. In order to keep the laser output at a constant stable output, the supply voltage detected by the detection means is controlled to increase corresponding to the displacement ,
Switching from the injection mode to the exhaust mode when the supply voltage drops to reach the first voltage;
A gas control device for a laser device , wherein the exhaust mode is switched to the injection mode when a supply voltage rises to reach a second voltage higher than the first voltage . In the injection mode, the injection amount is controlled so that the supply voltage continuously and gradually decreases,
2. The gas control device of a laser device according to claim 1, wherein in the exhaust mode, the exhaust amount is controlled so that the supply voltage continuously and gradually increases. 3. The gas control apparatus for a laser apparatus according to claim 1, wherein the laser output is controlled within a supply voltage range in which control for maintaining the laser output at a constant stable output is possible. Switching from the exhaust mode to the injection mode at an upper limit supply voltage within a range where control capable of maintaining the laser output at a constant stable output is performed, and lower limit supply within a range capable of control maintaining the laser output at a constant stable output. The gas control device for a laser device according to any one of claims 1 to 3, wherein the injection mode is switched to the exhaust mode by voltage. The upper limit supply voltage is a value lower than the upper limit supply voltage by a predetermined amount,
The gas control device for a laser device according to claim 4, wherein the lower limit supply voltage is a value higher by a predetermined amount than the lower limit supply voltage. The gas control device for a laser device according to any one of claims 1 to 5, wherein the injection amount and the exhaust amount are controlled in accordance with the number of laser oscillation pulses. Start control from the injection mode,
Further, the laser chamber, the gas control device for a laser device according to any one of claims 1 to 6, the laser gas with optimum mixing ratio of before laser oscillation, characterized in that it is filled.

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