JP3761260B2 - Gas laser apparatus and laser gas injection method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser gas injection method for a gas laser device.
[0002]
[Prior art]
In a gas laser device, a medium gas that oscillates laser light is enclosed in a container (hereinafter referred to as a laser chamber), and is discharged with a high-voltage pulse between electrodes. Is generated. Among gas laser devices, in excimer laser devices such as excimer laser devices, there are various factors depending on the reaction between a medium gas (hereinafter referred to as laser gas) and the components inside the laser chamber, sputtering of electrode members by discharge, etc. Dust of a new material is generated and floats in the laser chamber. This floating dust is attached to a window that transmits laser light and exits from the inside of the laser chamber to the outside, which is a major factor for reducing laser output. In particular, in an excimer laser device, since a halogen gas is used as a laser gas, a metal halide is contained in dust, and the metal halide may adhere to the window and corrode. Therefore, various ideas have been conventionally made to reduce the amount of floating dust.
[0003]
FIG. 5 and FIG. 6 show an example of the prior art for reducing the amount of floating dust as described above, which will be described below with reference to FIG. Here, an example of an excimer laser device is shown as a gas laser device, FIG. 5 shows a cross-sectional view of a laser chamber orthogonal to the laser optical axis, and FIG. 6 shows a side view of the gas laser device.
[0004]
Inside the laser chamber 4, a pair of main discharge electrodes 22a and 22b for performing main discharge for exciting laser gas is provided, and each of the main discharge electrodes 22a and 22b has an elongated shape in the optical axis direction. is doing. One main discharge electrode 22a is attached to an insulator 21 provided on the outer peripheral wall of the laser chamber 4, and the other main discharge electrode 22b is electrically conductive in the laser chamber 4 through a support member 33 having conductivity. It is supported on the side wall of. In addition, a pair of preionization electrodes 36a and 36b for preionizing the laser gas is disposed on the side of the main discharge space of the main discharge electrodes 22a and 22b. The preionization electrode 36b is attached to the conductive side wall of the laser chamber 4, and the preionization electrode 36a is connected to a power supply terminal 34 attached to the side wall of the laser chamber 4 through an insulator. . Further, the main discharge electrode 22 a is connected to the power supply terminal 35. The power supply terminal 35 is connected to a main discharge voltage output terminal of a discharge power supply (not shown), the power supply terminal 34 is connected to a preliminary discharge voltage output terminal of the discharge power supply, and the conductive side wall (that is, the main discharge) of the laser chamber 4. The electrode 22b and the preionization electrode 36b) are connected to a common output terminal of the discharge power source.
[0005]
In the laser chamber 4, a cross flow fan 39 for circulating the laser gas and a radiator 40 for cooling the laser gas heated by the discharge are provided. Then, the laser gas flows into the main discharge space between the main discharge electrodes 22 a and 22 b along the arrow 24 by the cross flow fan 39, passes through the radiator 40, is cooled, and returns to the cross flow fan 39 to return to the main flow. It has become.
A laser gas supply pipe 41 is provided on the side wall of the laser chamber 4, and the gas injection direction of the laser gas supply pipe 41 faces the bottom surface of the laser chamber 4. At the time of exchanging the laser gas, the laser gas is injected from a laser gas cylinder provided outside through the laser gas supply pipe 41.
[0006]
Further, a filter 29 is provided on the side of the laser chamber 4. The laser gas inside the laser chamber 4 is guided to the filter 29 via the pipe line 26, and the gas output from the filter 29 is returned to the inside of the laser chamber 4 via the pipe line 27 and the pipe line 28. At this time, the returned gas is blown in the vicinity of the window 25.
[0007]
According to the above configuration, the laser gas is excited by the main discharge 23 between the main discharge electrodes 22 a and 22 b to oscillate the laser beam 30, and the laser beam 30 is emitted from the front window 25. When the laser beam is oscillating, the cross flow fan 39 causes the laser gas to flow back through the main discharge space and the radiator 40 in the direction of the arrow 24. At the same time, the laser gas is guided to the filter 29 by the cross flow fan 39 via the pipe line 26, and after the dust in the laser gas is removed by the filter 29, the gas from which the dust has been removed passes through the pipe lines 27 and 28. It is sprayed in the vicinity of the window 25 via. Since this gas acts as an air curtain for the window 25, dust in the laser chamber 4 is prevented from adhering to the window 25.
[0008]
In addition, as another example of the conventional technique further advanced from the above, a technique in which a protruding member such as a labyrinth is provided in a small space between the window 25 and the inside of the laser chamber 4 has been proposed. This is because when the shock wave due to the main discharge moves the laser gas containing dust in the direction of the window 25, the laser gas creates a vortex in the portion of the projecting member and the energy of the shock wave is attenuated. This utilizes the fact that the amount of laser gas reaching the window 25 is reduced.
[0009]
[Problems to be solved by the invention]
In the gas laser apparatus as described above, when the laser gas deteriorates and the output decreases, it is necessary to replace the laser gas. However, when the laser gas is injected through the laser gas supply pipe 41, the laser gas hits the bottom surface of the laser chamber 4, so that dust adhering to the bottom surface is blown up. As a result, since dust adheres to the window 25, there is a problem that the laser gas exchange effect is lost and the laser output after the laser gas exchange is lowered.
[0010]
The present invention has been made paying attention to the above-mentioned problems, and an object thereof is to provide a gas laser device and a laser gas injection method thereof that can prevent dust from adhering to the window 25 during laser gas injection.
[0011]
[Means, actions and effects for solving the problems]
In order to achieve the above object, the invention described in claim 1 includes a laser chamber 4 that encloses a laser gas, a window 25 that transmits laser light oscillated in the laser chamber 4 and emits the laser light, and a laser. A cross-flow fan 39 that is disposed in the chamber 4 and recirculates the laser gas, a filter 29 that is attached to the laser chamber 4 and blows the window 25 after the laser gas is cleaned, and the laser gas is replaced when the laser gas is replaced. In a gas laser device having an exhaust device for exhausting from the chamber 4 and an injection device for injecting a laser gas into the laser chamber 4,
A gas pressure setting means for setting a gas pressure value in the laser chamber 4 after exhausting the laser gas;
A gas pressure detector 5 for detecting a gas pressure value in the laser chamber 4;
After comparing the gas pressure value detected by the gas pressure detector 5 with the gas pressure value set by the gas pressure setting means and driving the exhaust device until both gas pressure values substantially match, the laser gas is exhausted, The controller 1 is configured to drive the injection device while rotating the cross flow fan 39 to inject laser gas into the laser chamber 4 through the filter 29.
[0012]
Further, in the invention described in claim 10, the laser gas in the laser chamber 4 is refluxed by the cross flow fan 39, and the laser gas is cleaned through the filter 29 and then blown to the window 25. In the laser gas injection method when exchanging the laser gas of the gas laser device that excites the laser gas to excite the laser gas and oscillates the laser beam,
The gas pressure value in the laser chamber 4 after the laser gas exhaust is set, and after the laser gas is exhausted to this gas pressure value, a new laser gas is injected into the laser chamber 4 and the cross flow fan 39 is rotated to perform the injection. The cleaned laser gas is passed through the filter 29 and the cleaned laser gas is blown onto the window.
[0013]
According to the first and tenth aspects of the present invention, when the laser gas is exhausted, the laser chamber is not evacuated but exhausted so that a trace amount of laser gas corresponding to a predetermined gas pressure value remains. After this evacuation, a new laser gas is injected into the laser chamber, so that the gas flow is not disturbed as in a vacuum state, and dust accumulated at the bottom of the laser chamber 4 is rolled up. Less. Further, at this time, since the laser gas is injected while rotating the cross flow fan, the laser gas is guided to the filter 29, dust is removed, and the cleaned laser gas is blown onto the window. Therefore, the window is prevented from being contaminated with dust.
[0014]
The invention according to claim 2 is provided in the laser chamber 4 in which the laser gas is sealed, the window 25 that transmits the laser light oscillated in the laser chamber 4 and is emitted to the outside, and A cross flow fan 39 for refluxing the laser gas, a filter 29 attached to the laser chamber 4 and sprayed onto the window 25 after cleaning the laser gas, and an exhaust device for exhausting the laser gas from the laser chamber 4 when the laser gas is replaced In a gas laser device having an injection device for injecting a laser gas into the laser chamber 4,
A gas pressure setting means for setting a gas pressure value in the laser chamber 4 after exhausting the laser gas;
A gas pressure detector 5 for detecting a gas pressure value in the laser chamber 4;
After comparing the gas pressure value detected by the gas pressure detector 5 with the gas pressure value set by the gas pressure setting means and driving the exhaust device until both gas pressure values substantially match, the laser gas is exhausted, The injection device is driven while rotating the cross flow fan 39 until the gas pressure values detected by the gas pressure detector 5 in the order of rare gas, halogen gas, and rare gas are substantially equal to a predetermined value. The controller 1 is configured to inject into the laser chamber 4 through the filter 29.
[0015]
According to the eleventh aspect of the present invention, the laser gas in the laser chamber 4 is recirculated by the cross flow fan 39, and the laser gas is cleaned through the filter 29 and then blown onto the window 25. In the laser gas injection method when exchanging the laser gas of the gas laser device that discharges within 4 to excite the laser gas and oscillates the laser beam,
After setting the gas pressure value in the laser chamber 4 after exhausting the laser gas, the laser gas is exhausted to this gas pressure value, and then a new laser gas is injected into the laser chamber 4 in the order of rare gas, halogen gas, and rare gas to a predetermined pressure. At the same time, the cross flow fan 39 is rotated so that the laser gas passes through the filter 29 and the cleaned laser gas is blown onto the window.
[0016]
According to the second and eleventh aspects of the invention, when the laser gas is exhausted, the laser chamber is not evacuated but exhausted so that a trace amount of laser gas corresponding to a predetermined gas pressure value remains. After this evacuation, a new laser gas is injected into the laser chamber, so that the gas flow is not disturbed as in a vacuum state, and dust accumulated at the bottom of the laser chamber 4 is rolled up. Less. As the injection sequence of the laser gas, first, a rare gas is injected to a certain predetermined pressure, then a trace amount of halogen gas is injected to a predetermined pressure, and finally, the rare gas is injected again to a predetermined pressure. Therefore, since the rare gas is injected until the gas pressure reaches a certain level at the initial stage of injection, the next time the halogen gas is injected, the gas pressure can be accurately detected by a gas pressure detector or the like. The gas partial pressure of the gas is accurately detected. Further, at this time, since the laser gas is injected while rotating the cross flow fan, the laser gas is guided to the filter 29 to remove dust, and the cleaned laser gas is blown onto the window. Therefore, the window is prevented from being contaminated with dust.
[0017]
According to a third aspect of the present invention, in the gas laser apparatus according to the first or second aspect, the controller 1 rotates the cross flow fan 39 only during an initial predetermined time for injecting the laser gas, and the laser gas is supplied to the laser gas. Injection into the laser chamber 4 through the filter 29 is performed.
[0018]
The invention according to claim 12 is the laser gas injection method according to claim 10 or 11,
The cross flow fan 39 is rotated only during the initial predetermined time when laser gas is injected, and the laser gas is injected into the laser chamber 4 via the filter 29.
[0019]
According to the third and twelfth aspects of the present invention, since the amount of laser gas in the laser chamber is very small immediately after the laser gas is exhausted, there is a possibility that the gas flow may be disturbed when a new laser gas is injected. Due to this turbulence in the gas flow, dust accumulated at the bottom of the laser chamber is rolled up. Therefore, the cross flow fan is rotated only during a predetermined time at the initial stage of laser gas injection until the above-described gas flow disturbance is eliminated, so that the laser gas to be injected passes through the filter 29. Thus, the dust is removed by the filter 29, and the cleaned laser gas acts as an air curtain on the window, so that the window is prevented from being contaminated with dust.
[0020]
According to a fourth aspect of the present invention, in the gas laser apparatus according to the first or second aspect, the controller 1 is an initial stage of injecting the laser gas, and the gas pressure in the laser chamber 4 reaches a predetermined gas pressure value. The cross flow fan 39 is rotated only during the period until the laser gas is injected into the laser chamber 4 via the filter 29.
[0021]
The invention described in claim 13 is the laser gas injection method according to claim 10 or 11,
The cross flow fan 39 is rotated only in the initial stage of laser gas injection and until the gas pressure in the laser chamber 4 reaches a predetermined gas pressure value, and the laser gas passes through the filter 29 to enter the laser chamber 4. The way to inject.
[0022]
According to the fourth and thirteenth aspects of the present invention, since the amount of laser gas in the laser chamber is very small immediately after the laser gas is exhausted, there is a possibility that the gas flow may be disturbed when a new laser gas is injected. Due to this turbulence in the gas flow, dust accumulated at the bottom of the laser chamber is rolled up. Therefore, the crossing is performed only at the initial stage of laser gas injection and until a predetermined amount of laser gas is injected into the laser chamber, that is, until the gas pressure reaches a predetermined value and the above gas flow disturbance is eliminated. The flow fan is rotated so that the injected laser gas passes through the filter 29. Thus, the dust is removed by the filter 29, and the cleaned laser gas acts as an air curtain on the window, so that the window is prevented from being contaminated with dust.
[0023]
The invention according to claim 5 is the gas laser device according to claim 2,
The controller 1 rotates the cross flow fan 39 only when the first rare gas is injected, and the laser gas is injected into the laser chamber 4 via the filter 29.
[0024]
The invention as set forth in claim 14 is the laser gas injection method according to claim 11, wherein
Only when the first rare gas is injected, the cross flow fan 39 is rotated, and the rare gas is injected into the laser chamber 4 via the filter 29.
[0025]
According to the invention described in claims 5 and 14, since the amount of laser gas in the laser chamber becomes very small immediately after exhausting the laser gas, there is a possibility that the flow of this gas may be disturbed when a new laser gas is injected. Due to this turbulence in the gas flow, dust accumulated at the bottom of the laser chamber is rolled up. Therefore, only when the first rare gas of the laser gas is injected, the cross flow fan is rotated so that the injected rare gas passes through the filter 29. Thus, the dust is removed by the filter 29, and the purified rare gas acts as an air curtain on the window, so that the window is prevented from being contaminated with dust. In addition, when a predetermined amount of rare gas is injected into the laser chamber, the gas flow is not disturbed and dust does not roll up as described above, so that the window is not contaminated with dust.
[0026]
The invention according to claim 6 is the gas laser device according to any one of claims 1 to 5,
The laser gas is injected into the laser chamber 4 in a direction other than the bottom surface of the laser chamber 4.
[0027]
According to the invention described in claim 6, since the laser gas is injected into the laser chamber in a direction other than the bottom surface of the laser chamber, the laser gas is not sprayed directly on the bottom surface but is deposited on the bottom. The possibility of winding up dust is reduced. Therefore, dust is less likely to enter the laser gas when the laser gas is injected.
[0028]
Invention of Claim 7 is the gas laser apparatus as described in any one of Claims 1-5,
A gas inlet through which laser gas is injected into the laser chamber 4 is provided in the upper portion of the laser chamber 4.
[0029]
According to the seventh aspect of the present invention, since the gas inlet through which the laser gas is injected into the laser chamber is provided at the upper part in the laser chamber 4, the laser gas is not directly blown onto the bottom surface, and the bottom is The possibility of winding up accumulated dust is reduced. Therefore, dust is less likely to enter the laser gas when the laser gas is injected.
[0030]
Invention of Claim 8 is the gas laser apparatus as described in any one of Claims 1-5,
A gas inlet for injecting laser gas into the laser chamber 4 is provided between the downstream side of the filter 29 and the window 25 in the gas flow by the cross flow fan 39.
[0031]
According to the eighth aspect of the present invention, the gas injection port into which the laser gas is injected into the laser chamber is provided between the downstream of the gas flow filter 29 by the cross flow fan and the window. The cleaned clean laser gas is blown onto the window along the gas flow. Therefore, the window is not contaminated with dust.
[0032]
The invention according to claim 9 is the gas laser device according to any one of claims 1 to 5,
A gas exhaust port for exhausting laser gas from the laser chamber 4 is provided between the window 25 and the inlet of the filter 29.
[0033]
According to the invention described in claim 9, since the gas exhaust port for exhausting the laser gas from the inside of the laser chamber is provided between the window and the inlet of the filter 29, the laser gas is exhausted from the window to the inside of the laser chamber. A laser gas flow is generated toward the. Therefore, the dust in the laser chamber does not move toward the window, and the window is not contaminated with dust.
[0034]
According to a fifteenth aspect of the present invention, in the laser gas injection method at the time of exchanging the laser gas of the gas laser device that excites the laser gas by exciting inside the laser chamber 4 filled with the laser gas and oscillates the laser beam,
After the laser gas in the laser chamber 4 is exhausted, when the laser gas is injected into the laser chamber 4, the laser gas flow rate is limited to a predetermined value for a predetermined time at the beginning of the injection, and after the predetermined time has elapsed, the laser gas flow rate is reduced. This is a method of injecting by increasing from this limit value.
[0035]
According to the fifteenth aspect of the present invention, since the amount of laser gas in the laser chamber is very small immediately after the laser gas is exhausted, there is a possibility that the gas flow may be disturbed when a new laser gas is injected. Due to this turbulence in the gas flow, dust accumulated at the bottom of the laser chamber is rolled up. Therefore, the flow rate of the laser gas to be injected is limited by limiting the flow rate of the laser gas to a predetermined value only for a predetermined time at the initial stage of laser gas injection until the above-described gas flow disturbance is eliminated. Thus, the dust is not rolled up and the window is prevented from being contaminated with dust.
[0036]
The invention according to claim 16 is a laser gas injection method at the time of exchanging the laser gas of a gas laser device that excites the laser gas by exciting inside the laser chamber 4 in which the laser gas is sealed to oscillate the laser beam.
After the laser gas in the laser chamber 4 is exhausted, when the laser gas is injected into the laser chamber 4, the laser gas flow rate is limited to a predetermined value at the initial stage of injection and until the gas pressure reaches a predetermined pressure value. After the pressure reaches the predetermined pressure value, the laser gas flow rate is increased and injection is performed.
[0037]
According to the sixteenth aspect of the present invention, since the amount of laser gas in the laser chamber is very small immediately after the laser gas is exhausted, there is a possibility that the gas flow may be disturbed when a new laser gas is injected. Due to this turbulence in the gas flow, dust accumulated at the bottom of the laser chamber is rolled up. Therefore, at the initial stage of laser gas injection until the laser gas injection amount becomes a predetermined amount or more, that is, until the gas pressure becomes a predetermined value or more and the above gas flow disturbance is eliminated, the laser gas flow rate is set to a predetermined value. Limit the value to limit the flow rate of the injected laser gas. Thus, the dust is not rolled up and the window is prevented from being contaminated with dust.
[0038]
The invention described in claim 17 is the laser gas injection method according to claim 15 or 16,
When the laser gas in the laser chamber 4 is exhausted, a gas pressure value in the laser chamber 4 after the laser gas is exhausted is set, and the laser gas is exhausted to this gas pressure value.
[0039]
According to the invention described in claim 17, when the laser gas is exhausted, the gas is exhausted to a predetermined gas pressure value set in advance so that a predetermined amount of the laser gas remains. The remaining trace amount of the laser gas eliminates the disturbance of the gas flow, so that dust does not roll up with the injected laser gas. Therefore, by limiting the gas flow rate at the time of laser gas injection and reducing the flow velocity, the possibility of further dust dusting is reduced, and the window is prevented from being contaminated with dust.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a gas laser device and a laser gas injection method thereof according to the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of a laser chamber of a gas laser apparatus according to the present invention. Here, an excimer laser device is described as an example of the gas laser device, and the same components as those in FIG. 5 described in the prior art are denoted by the same reference numerals.
A filter 29 is provided on the side of the laser chamber 4, and the inside of the laser chamber 4 communicates with the gas inlet of the filter 29 via a pipe line 26. Further, the gas outlet of the filter 29 communicates with the vicinity of the window 25 through the pipe lines 27 and 28 as described above. (See FIG. 6) The inlet of the conduit 26 on the laser chamber 4 side is provided at a position where the gas recirculation path by the rotation of the cross flow fan 39 is intermediate from the cross flow fan 39 to the main discharge electrodes 22a and 22b. Is desirable. When the cross flow fan 39 rotates, the laser gas in the laser chamber 4 is guided to the filter 29 via the pipe line 26 so that the cleaned laser gas is blown to the window 25 and returned to the laser chamber 4. It has become.
[0041]
The laser chamber 4 is connected to a pipe for injecting laser gas from an external laser gas supply means (for example, a gas cylinder). This pipe has a gas outlet on the laser chamber 4 side other than the vicinity of the bottom surface, that is, in the upper part of the laser chamber 4, and the injection direction of the laser gas is the bottom surface, for example, as shown in the pipes 42, 43, and 44 shown in the figure. It is provided to face other than. Further, as indicated by the pipe 44, by directing the injection direction of the laser gas from the inside of the laser chamber 4 toward the filter 29, a gas flow in a direction passing through the filter 29 is generated when the laser gas is injected. These conduits 42, 43, 44 can be selected by a valve or the like (not shown) provided outside. In addition, an exhaust device is connected so that the laser gas in the laser chamber 4 can be exhausted via these pipe lines 42, 43, 44.
[0042]
FIG. 2 is a block diagram showing the configuration of a gas laser apparatus for explaining the laser gas injection method according to the present invention. In the excimer laser device, a mixed gas of a halogen gas and a rare gas is used as a laser gas. In this embodiment, an example of using fluorine gas, krypton gas, and neon gas is shown. As the laser oscillation time elapses, the amount of impurities contained in the laser gas increases or the halogen gas concentration decreases, so that the laser gas gradually deteriorates. It needs to be replaced. For this purpose, an exhaust device for exhausting the deteriorated laser gas is connected to the laser chamber 4. In this embodiment, as an example of the exhaust device, a vacuum pump 20 is provided via a valve 19 and a trap 18. Is connected. Inside the vacuum pump 20, a filter or the like containing activated carbon for removing halogen gas is mounted. The trap 18 is necessary for the excimer laser device and adsorbs the halogen gas in the exhausted laser gas. As a result, the exhaust gas is exhausted after the halogen gas which is harmful to the human body and has a harmful effect such as an abnormal temperature rise on the filter of the vacuum pump 20 is removed.
[0043]
An injection device for injecting each laser gas into the laser chamber 4 is connected. That is, a fluorine and neon mixed gas cylinder 8 is connected to the laser chamber 4 via a valve 11, a krypton gas cylinder 9 is connected via a valve 12, and a neon gas cylinder 10 is connected via a valve 13. The gas pipelines between the valves 11, 12, 13, 19 and the laser chamber 4 may be provided separately or in common. The laser chamber 4 is provided with a gas pressure detector 5 for detecting the internal gas pressure. Each valve 11, 12, 13, 19 is constituted by an electromagnetic valve or an air-driven valve via an electromagnetic valve. And the drive command of each of these valves and the drive command of the vacuum pump 20 are outputted from the controller 1, and the detection signal of the gas pressure detector 5 is connected to the controller 1.
[0044]
The controller 1 is composed of a computer system mainly composed of a microcomputer, for example. In addition to the above signals, the controller 1 receives a monitor signal for monitoring laser output power and laser characteristics from a monitor device (not shown) or a command signal such as a gas exchange command from another external device (not shown). Entered. When the gas exchange command is input from the external device, the controller 1 controls the driving of the valves and the vacuum pump 20 based on the detection signal of the gas pressure detector 5 and starts exchanging laser gas.
The gas pressure setting device 2 sets the gas pressure value inside the laser chamber 4 after the laser gas is exhausted. For example, the set value may be input using a numeric keypad or a setting switch. This set value data is input to the controller 1. As the gas pressure setting means, set value data set in advance in the external device or the like may be input by communication or the like.
[0045]
FIG. 3 shows an example of a control flowchart showing a laser gas injection method according to the present embodiment. Specifically, the processing is performed by the controller 1 described above. Here, each step number is indicated by S.
In S1, the gas pressure Pr in the laser chamber 4 after exhaust is set by the set value data input from the gas pressure setting device 2, and then in S2, the gas pressure in the laser chamber 4 detected by the gas pressure detector 5 is set. Read the gas pressure Pc. In S3, the gas pressure Pc is compared with the set gas pressure Pr to determine whether or not the gas pressure Pc is greater than the gas pressure Pr. If the result of this determination is large, the vacuum pump 20 is driven in S4, the valve 19 is opened to continue the exhaust of the laser gas, and then the process returns to S2 to repeat the process. Further, when it is not large in the judgment of S3, that is, when the gas pressure Pc becomes equal to or lower than the gas pressure Pr, in S5, the vacuum pump 20 is stopped, the valve 19 is closed and the exhaust is stopped. The flow fan 39 is rotated. Next, a new laser gas is injected in S6. Here, each valve 11, 12, 13 is controlled to a predetermined opening, and each gas flow rate from the mixed gas cylinder 8, the krypton gas cylinder 9, and the neon gas cylinder 10 is adjusted to a predetermined value.
[0046]
In step S7, the gas pressure Pc detected by the gas pressure detector 5 is read, and it is determined whether or not the gas pressure Pc is equal to or higher than a predetermined pressure value. Continue. When the gas pressure Pc becomes equal to or higher than the predetermined pressure value, the valves 11, 12, 13 are closed and the rotation of the cross flow fan 39 is stopped in S8, and the laser gas injection is finished.
[0047]
In the laser gas injection method, when the laser gas is exhausted until the inside of the laser chamber 4 is substantially vacuumed, dust accumulated on the bottom of the laser chamber 4 is lifted up when starting to inject a new laser gas. End up. Then, since the laser gas containing dust moves in the direction of the window 25 with almost no resistance, the window 25 may be contaminated by dust. Therefore, in the laser gas injection method of the present embodiment, as shown in S3 and S4 described above, a small amount of laser gas corresponding to the set gas pressure Pr is left inside the laser chamber 4 when the laser gas is exhausted. Then, in S5 and S6, a new laser gas is injected while the cross flow fan 39 is rotated. When the cross flow fan 39 rotates, a gas flow is generated by the remaining trace amount of the laser gas. When a new laser gas is injected, the laser gas is guided to the pipe 26 and passes through the filter 29 to the laser chamber. 4 will be injected. As a result, since the laser gas cleaned by the filter 29 is blown onto the surface of the window 25 from the initial stage of laser gas injection, the laser gas acts as an air curtain to prevent the window 25 from being contaminated by dust. Is done. In addition, since a very small amount of laser gas is left in the laser chamber 4, it is difficult for the gas flow to be disturbed even at the initial stage of injection of a new laser gas, and the possibility that the accumulated dust is rolled up is reduced.
[0048]
Then, as shown in S7, the cross flow fan 39 is rotated until the gas pressure of the new laser gas reaches a predetermined required gas pressure value. Here, the time for rotating the cross flow fan 39 is not limited to this embodiment. That is, at the initial stage of laser gas injection and until the injected laser gas reaches a predetermined amount and the above gas flow turbulence does not occur, that is, the gas pressure of the laser gas becomes a predetermined gas pressure value corresponding to the predetermined amount. The cross flow fan 39 may be rotated only for the time until it reaches. Furthermore, the cross flow fan 39 may be rotated only during an initial predetermined time from the start of laser gas injection until the predetermined gas pressure value is reached.
[0049]
Further, when laser gas is injected, any one of the pipelines 42, 43, 44 is selected and injected into the laser chamber 4. The gas inlets of the pipes 42, 43, and 44 are located in the upper part of the laser chamber 4, and the gas injection direction faces the direction other than the bottom surface, so that dust accumulated at the bottom of the laser chamber 4 is removed. The possibility of winding is reduced. As a result, it is possible to prevent dust from rolling up at the initial stage of laser gas injection. Furthermore, when laser gas is injected through the pipe 44, a gas flow is generated from the inside of the laser chamber 4 toward the filter 29, so that the laser gas cleaned by the filter 29 can be guided to the window 25. Therefore, similarly to the above, the window 25 can be prevented from being contaminated by dust, so that the laser output characteristics are less deteriorated.
[0050]
Note that the gas inlet into which the laser gas is injected may be provided between the window 25 and the downstream side of the filter 29 in the gas flow by the cross flow fan 39. In this case, since new laser gas not containing dust flows toward the window 25, the window 25 can be prevented from being contaminated by dust.
At this time, the gas exhaust port for exhausting the laser gas from the laser chamber 4 is preferably provided between the window 25 and the inlet side of the filter 29 separately from the gas injection port. As a result, a flow of laser gas is generated in the direction from the window 25 into the laser chamber 4 at the time of evacuation, so that the possibility that dust contained in the laser gas adheres to the window 25 is reduced.
[0051]
Next, a laser gas injection method according to the second embodiment will be described. The configuration of the gas laser apparatus according to this embodiment is the same as that of FIGS. 1 and 2 described in the previous embodiment, and a description thereof is omitted here.
[0052]
FIG. 4 shows an example of a control flowchart showing the laser gas injection method according to the present embodiment, which is processed by the controller 1 as described above.
In S11, the gas pressure Pr in the laser chamber 4 after exhaust is set by the set value data inputted from the gas pressure setting device 2, and then in S12, the gas pressure in the laser chamber 4 detected by the gas pressure detector 5 is set. Read the gas pressure Pc. In S13, the gas pressure Pc is compared with the set gas pressure Pr to determine whether or not the gas pressure Pc is greater than the gas pressure Pr. If the result of this determination is large, the vacuum pump 20 is driven in S14, the valve 19 is opened to continue the exhaust of the laser gas, and then the process returns to S12 and the process is repeated. If the judgment is negative in S13, that is, if the gas pressure Pc is equal to or lower than the gas pressure Pr, in S15, the vacuum pump 20 is stopped, the valve 19 is closed and the exhaust is stopped. The flow fan 39 is rotated. Next, in S16, the valves 12 and 13 are opened to a predetermined opening, the respective gas flow rates from the krypton gas cylinder 9 and the neon gas cylinder 10 are adjusted to predetermined values, and new krypton gas and neon gas are injected. In S17, the gas pressure Pc in the laser chamber 4 is read from the gas pressure detector 5, and it is determined whether or not the gas pressure Pc is equal to or higher than a predetermined pressure value P1. Return to, and continue to inject new krypton gas and neon gas. When the gas pressure Pc becomes equal to or higher than the predetermined pressure value P1, the process proceeds to S18.
[0053]
In S18, the valves 12 and 13 are closed to stop the injection of krypton gas and neon gas, and the rotation of the cross flow fan 39 is stopped. Next, in S19, the valve 11 is opened to a predetermined opening, the gas flow rate from the mixed gas cylinder 8 of fluorine and neon is adjusted to a predetermined value, and a new mixed gas of fluorine is injected. In S20, the gas pressure Pc in the laser chamber 4 is read from the gas pressure detector 5, and it is determined whether or not the gas pressure Pc is equal to or higher than a predetermined pressure value P2 (where P2> P1). While the value is smaller than the value P2, the process returns to S19 and the injection of the mixed gas of fluorine is continued. When the gas pressure Pc becomes equal to or higher than the predetermined pressure value P2, the valve 11 is closed and the injection of the fluorine mixed gas is stopped in S21. Next, in S22, the valves 12 and 13 are opened to a predetermined opening, and new krypton gas and neon gas are injected. In S23, the gas pressure Pc in the laser chamber 4 is read from the gas pressure detector 5, and it is determined whether or not the gas pressure Pc is equal to or higher than a predetermined pressure value P3 (where P3> P2). While the value is smaller than the value P3, the process returns to S22 and the injection of new krypton gas and neon gas is continued. When the gas pressure Pc becomes equal to or higher than the predetermined pressure value P3, the valves 12 and 13 are closed in S24, and the injection of krypton gas and neon gas is finished.
[0054]
In the above flowchart, when the laser gas is exhausted, as in the previous embodiment, a trace amount of laser gas corresponding to the set gas pressure Pr is left in the laser chamber 4 and then the cross flow fan 39 is rotated. A predetermined amount of new krypton gas and neon gas is injected. Accordingly, even when new laser gas is injected, the accumulated dust is less likely to be rolled up, and the laser gas injected via the filter 29 can prevent the window 25 from being contaminated by dust.
In addition, when the mixed gas of fluorine gas is injected, the cross flow fan 39 is stopped, but this is because the gas flow by the cross flow fan 39 becomes a noise in detecting the gas pressure when the fluorine gas is injected. It is for preventing. As a result, a partial pressure of a small amount of fluorine gas can be detected more accurately than other rare gases (krypton gas and neon gas) in the laser gas, so that the laser oscillation characteristics of the excimer laser device are greatly improved.
Also, after injecting the mixed gas of fluorine gas, when the last rare gas is injected, the rotation of the cross flow fan 39 is stopped. This is because a predetermined amount of laser gas has already been injected into the laser chamber 4. This is because there is little possibility of winding up dust by the injected gas. At this time, the last rare gas may be injected while rotating the cross flow fan 39.
[0055]
As a laser gas injection method after exhaust, the laser gas flow rate is limited to a predetermined value at the initial injection and until the gas pressure reaches a predetermined pressure value. After the gas pressure reaches the predetermined pressure value, The laser gas flow rate may be increased by exceeding this limit value. Similarly, the laser gas flow rate is limited to a predetermined value for a predetermined time at the initial stage of injection, that is, for a predetermined time until the predetermined pressure value is reached, and after the predetermined time has elapsed, the laser gas flow rate is limited to the predetermined value. You may make it increase from a value. In this case, as means for limiting the laser gas flow rate, for example, a mass flow control valve (mass flow control valve), an orifice, a filter, or the like may be provided at the outlet of the krypton gas cylinder 9 and the neon gas cylinder 10. By controlling the laser gas flow rate in this way, the gas flow rate can be slowed at the beginning of injection, so that the possibility of raising dust is reduced. Further, since the gas flow is not disturbed after a predetermined amount of laser gas is injected, the laser gas flow rate can be increased. Also in this case, if a small amount of laser gas is left when the laser gas is exhausted, the gas flow is not disturbed when the laser gas is injected, so that it is needless to say that the effect of reducing the dust winding is increased.
[Brief description of the drawings]
FIG. 1 is a sectional view of a laser chamber of a gas laser apparatus according to the present invention.
FIG. 2 is a block diagram showing the configuration of a gas laser apparatus according to the present invention.
FIG. 3 shows an example of a control flowchart representing the laser gas injection method according to the first embodiment of the present invention.
FIG. 4 shows an example of a control flowchart showing a laser gas injection method according to a second embodiment of the present invention.
FIG. 5 shows a cross-sectional view of a laser chamber of a gas laser apparatus according to the prior art.
FIG. 6 shows a side view of a gas laser device according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Controller, 2 ... Gas pressure setting device, 4 ... Laser chamber, 5 ... Gas pressure detector, 8 ... Mixed gas cylinder, 9 ... Krypton gas cylinder, 10 ... Neon gas cylinder, 11, 12, 13, 19 ... Valve, 18 DESCRIPTION OF SYMBOLS ... Trap, 20 ... Vacuum pump, 21 ... Insulator, 22a, 22b ... Main discharge electrode, 23 ... Main discharge, 24 ... Arrow, 25 ... Window, 26, 27, 28, 42, 43, 44 ... Pipe line, 29 DESCRIPTION OF SYMBOLS ... Filter, 30 ... Laser beam, 33 ... Supporting member, 34, 35 ... Feed terminal, 36a, 36b ... Preionization electrode, 39 ... Cross flow fan, 40 ... Radiator, 41 ... Laser gas supply line.

Claims (14)

  A laser chamber 4 that encloses a laser gas, a window 25 that transmits laser light oscillated in the laser chamber 4 and emits the laser light to the outside, and a crossflow fan 39 that is disposed in the laser chamber 4 and recirculates the laser gas. A filter 29 attached to the laser chamber 4 and sprayed onto the window 25 after cleaning the laser gas, an exhaust device for exhausting the laser gas from the laser chamber 4 when the laser gas is replaced, and injecting the laser gas into the laser chamber 4 In the gas laser apparatus having an injection device for performing the above operation, a gas pressure setting means for setting a gas pressure value in the laser chamber 4 after the laser gas is exhausted, a gas pressure detector 5 for detecting the gas pressure value in the laser chamber 4, and a gas The gas pressure value detected by the pressure detector 5 is compared with the gas pressure value set by the gas pressure setting means. Then, after exhausting the laser gas by driving the exhaust device until both gas pressure values substantially coincide with each other, the injection device is driven while rotating the cross flow fan 39, and the laser gas is passed through the filter 29. A gas laser device comprising a controller 1 for injecting the laser chamber 4.   A laser chamber 4 that encloses a laser gas, a window 25 that transmits laser light oscillated in the laser chamber 4 and emits it to the outside, and a crossflow fan 39 that is disposed in the laser chamber 4 and recirculates the laser gas. A filter 29 attached to the laser chamber 4 and sprayed onto the window 25 after cleaning the laser gas, an exhaust device for exhausting the laser gas from the laser chamber 4 when the laser gas is replaced, and injecting the laser gas into the laser chamber 4 In the gas laser apparatus having an injection device for performing the above operation, a gas pressure setting means for setting a gas pressure value in the laser chamber 4 after the laser gas is exhausted, a gas pressure detector 5 for detecting the gas pressure value in the laser chamber 4, and a gas The gas pressure value detected by the pressure detector 5 is compared with the gas pressure value set by the gas pressure setting means. Then, the exhaust device is driven to exhaust the laser gas until both gas pressure values substantially coincide with each other, and then the injection device is driven while the cross flow fan 39 is rotated, so that noble gas, halogen gas, noble gas A controller 1 for sequentially injecting each laser gas into the laser chamber 4 through the filter 29 until the gas pressure value detected by the gas pressure detector 5 substantially matches a predetermined value. Gas laser device.   3. The gas laser apparatus according to claim 1, wherein the controller 1 rotates the cross flow fan 39 only during an initial predetermined time for injecting the laser gas, and passes the laser gas through the filter 29 to the laser chamber 4. A gas laser device characterized by being injected into the inside.   3. The gas laser apparatus according to claim 1 or 2, wherein the controller 1 is configured so that the cross flow fan 39 is only in the initial stage of laser gas injection and until the gas pressure in the laser chamber 4 reaches a predetermined gas pressure value. , And the laser gas is injected into the laser chamber 4 via the filter 29.   3. The gas laser device according to claim 2, wherein the controller 1 rotates the cross flow fan 39 only when the first rare gas is injected, and the laser gas passes through the filter 29 into the laser chamber 4. A gas laser device that is injected.   6. The gas laser device according to claim 1, wherein a laser gas is injected into the laser chamber 4 in a direction other than a bottom surface of the laser chamber 4.   6. The gas laser apparatus according to claim 1, wherein a gas injection port into which a laser gas is injected into the laser chamber 4 is provided in an upper portion of the laser chamber 4. .   6. The gas laser apparatus according to claim 1, wherein a gas injection port into which laser gas is injected into the laser chamber 4 includes a downstream side of the filter 29 in a gas flow by the cross flow fan 39. A gas laser device provided between the window and the window.   6. The gas laser device according to claim 1, wherein a gas exhaust port for exhausting a laser gas from the laser chamber 4 is provided between the window 25 and the inlet of the filter 29. A characteristic gas laser device.   The laser gas in the laser chamber 4 is recirculated by the cross flow fan 39, and the laser gas is cleaned through the filter 29 and then blown to the window 25. The laser gas is discharged in the laser chamber 4 to excite the laser gas. In a laser gas injection method at the time of laser gas exchange of a gas laser device that oscillates laser light, a gas pressure value in the laser chamber 4 after the laser gas is exhausted is set, and after the laser gas is exhausted to this gas pressure value, a new laser gas is supplied to the laser chamber 4 A laser gas injection method, wherein the cross flow fan 39 is rotated to cause the injected laser gas to pass through the filter 29 and the cleaned laser gas is blown onto the window.   The laser gas in the laser chamber 4 is recirculated by the cross flow fan 39, and the laser gas is cleaned through the filter 29 and then blown to the window 25. The laser gas is discharged in the laser chamber 4 to excite the laser gas. In the laser gas injection method at the time of exchanging the laser gas of the gas laser device that oscillates the laser beam, the gas pressure value in the laser chamber 4 after the laser gas is exhausted is set, and after the laser gas is exhausted to this gas pressure value, a new laser gas is used as a rare gas, Halogen gas and rare gas are sequentially injected into the laser chamber 4 to a predetermined pressure, and the cross flow fan 39 is rotated to cause the laser gas to pass through the filter 29, and the cleaned laser gas is blown onto the window. Laser gas injection method characterized in that   12. The laser gas injection method according to claim 10 or 11, wherein the cross flow fan 39 is rotated only during an initial predetermined time for injecting the laser gas, and the laser gas is injected into the laser chamber 4 through the filter 29. A laser gas injection method characterized by the above.   12. The laser gas injection method according to claim 10 or 11, wherein the cross flow fan 39 is rotated only at an initial stage of laser gas injection and until a gas pressure in the laser chamber 4 reaches a predetermined gas pressure value. A laser gas injection method, wherein a laser gas is injected into the laser chamber 4 through the filter 29.   The laser gas injection method according to claim 11, wherein the cross flow fan 39 is rotated only when the first rare gas is injected, and the rare gas is injected into the laser chamber 4 via the filter 29. A laser gas injection method characterized.

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