JPS62281486A - Rare-gas halide excimer laser device - Google Patents

Abstract

PURPOSE:To obtain a device capable of restoring an excimer laser in a short time after the inside of a laser vessel is exposed to air and having excellent operation efficiency by mounting a rare-gas supply section supplying the laser vessel with a rare gas and a control section conducting specific operation. CONSTITUTION:A rare-gas supply section 8 supplying a laser vessel 1 with a rare gas and a control section 9 restoring the inside of the laser vessel 1 to the state proper to laser oscillations after the laser vessel 1 is exposed to air are installed. The control section 9 performs a first process in which the rare-gas supply section 8 is controlled after the laser vessel 1 is exposed to air and the laser vessel 1 is supplied with the rare gas, a second process in which an excitation power circuit 7 is controlled and discharge is generated, a third process in which the rare-gas supply section 8 or laser-gas supply and evacuation sections 4, 6 are controlled and the rare gas in the laser vessel 1 is evacuated, and a fourth process, in which the laser-gas supply and evacuation sections 4, 6 are controlled and a laser gas is sealed into the laser vessel 1, in succession.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention provides a discharge electrode for obtaining laser oscillation, an excitation power supply circuit, a reflector for laser oscillation, and a device that enables laser oscillation. The present invention relates to a rare gas halide excimer laser device (hereinafter simply referred to as an excimer laser device) that includes at least a laser gas supply/exhaust section and a laser container enclosing laser gas.

(Prior Art) In an excimer laser, after long-time operation, the laser oscillation reflector or laser light extraction window (hereinafter referred to as
Laser light absorbing substances adhere to the optical windows (collectively referred to as optical windows), resulting in a decrease in laser output.

Therefore, the optical window must be replaced or cleaned, and the inside of the laser container must be exposed to air. When air comes into contact with a discharge electrode (hereinafter simply referred to as an electrode) used for discharge to excite a laser, impurities such as moisture and oxygen in the air adhere to the electrode surface. Therefore, when a laser gas that enables laser oscillation (hereinafter simply referred to as laser gas) is sealed and discharged, impurities on the electrode surface are knocked out and mixed into the laser gas, making it impossible to obtain laser output in a short time.

Furthermore, a chemical reaction between the halogen gas, which is a component of the laser gas, and the electrode surface reduces the amount of halogen gas or generates impurities, accelerating the decrease in laser output.

In conventional excimer laser equipment, in order to prevent the laser output from being lost in a short time, that is, to restore the excimer laser to the state before exposing the inside of the laser container to air (hereinafter simply "recovering the excimer laser"). "), the excimer laser was recovered by filling it with halogen gas diluted with a rare gas, which is a component of the laser gas, for a long period of about 12 hours. Regarding this, please refer to the instruction manual for excimer lasers published by Lumonics of Canada. book(
PRIILIM Engineering NARYrN8'rRUCT Engineering ONM
AN[TAIJ LσMoN 工C8HYPI! lR]
f3 EXCXMERL from 1nX-400i9ER
AB"1.R75QQQHK4F), P, 3-13.

FIG. 4 is a configuration diagram of a conventional excimer laser device, and only the parts related to the present application are shown. When the excimer laser device is operated for a long time, substances that absorb laser light adhere to the optical window 3, resulting in a decrease in laser output. For this reason, the optical window 3
It becomes necessary to replace or clean the laser container 1, and the inside of the laser container 1 must be exposed to air. When air comes into contact with the electrode 2, impurities such as moisture and oxygen in the air adhere to the surface of the electrode 2. Therefore, the air is exhausted using the exhaust pump 6,
After that, even if the laser gas obtained from the laser gas supply section 4 necessary for laser excitation is sealed and the laser gas is discharged using the excitation power supply circuit section 7, impurities will be knocked out from the surface of the electrode 2 and mixed into the laser gas. , it becomes impossible to obtain laser output in a short time. Furthermore, the component of the laser gas, ノ10gen1jlj■hxp-^^=, is added to the oni==l^
ILA-Shinpi? The decrease in laser output is accelerated due to a decrease in gas or the generation of impurities.

(Problems to be Solved by the Invention) Conventional excimer laser devices require a long recovery time of 12 hours to recover the excimer laser.

This is a big problem in terms of operating efficiency of the device.

SUMMARY OF THE INVENTION An object of the present invention is to provide an excimer laser device that has excellent operating efficiency and can restore the excimer laser in a short time after exposing the inside of a laser container to air.

(Means for Solving the Problems) Means provided by the present invention to solve the above-mentioned problems includes: a laser container in which a laser gas is sealed; an electrode that discharges within the laser container; an excitation power supply circuit that supplies a high voltage to the discharge electrode to cause a discharge; a laser oscillation reflector that reflects laser light generated in the laser container by the discharge to cause laser oscillation; and the laser container. A rare gas/ride excimer laser device comprising: a laser gas supply/exhaust section for discharging the laser gas from the laser containers 1-7; a rare gas supply section for supplying rare gas to the laser container; a control section that restores the interior of the laser container to a state suitable for laser oscillation after the laser container has been exposed to air; a first step of controlling the supply section to supply the rare gas to the laser container; a second step of controlling the excitation power supply circuit to cause the discharge; and the rare gas supply section or the laser gas supply. A third step of controlling the exhaust section to exhaust the rare gas in the laser container, and a fourth step of controlling the laser gas supply and exhaust section to fill the laser gas in the laser container are sequentially performed. It is characterized by

(Function) In the apparatus of the present invention, sequence control consisting of the first to fourth steps is performed by the control unit provided, a rare gas such as He is sealed, and a suitable time (approximately 10 minutes) is performed.
The system generates a discharge, evacuates it, and then fills it with laser gas. Due to the discharge in the rare gas, impurities such as moisture and oxygen adhering to the electrode surface are driven out into the rare gas, so that the impurities on the electrode surface can be removed by exhausting after the discharge. Next, if laser gas is sealed, the laser output will not decrease in a short period of time. Therefore, in the apparatus of the present invention, only a short time is required to restore the excimer laser.

(Embodiment) FIG. 1 is a block diagram showing a first embodiment of the present invention. The difference from the conventional device is that it is equipped with an Hθ supply section 8 and a control section 9. In this embodiment, in order to restore the excimer laser, Hs is sealed into the laser container 1 from the H8 supply section 8 under sequential control from the controller section 9, and then the excitation power supply circuit section 7 is used to fill the laser container 1 with Hs for an appropriate period of time (approximately 10 2) discharge, exhaust the gas using the exhaust pump 6, and then fill it with laser gas from the laser gas supply section 4. By discharging He, impurities such as moisture and oxygen adhering to the surface of the electrode 2 are thrown out into the He gas, so that the impurities on the surface of the electrode 2 can be removed by exhausting after the discharge. After that, the laser gas is sealed in the laser container, so there is no possibility that the laser output will not be obtained in a short period of time.

The time required to restore the excimer laser is only 10 minutes for the discharge, and therefore, in the excimer laser device of this embodiment, the excimer laser can be restored in a short time.

FIG. 2 is a block diagram showing a second embodiment of the present invention. The difference from the conventional device is the same as the embodiment shown in FIG. Under proper control, He is first sealed into the laser container 1 from the He supply section 8, and discharged for an appropriate time (approximately 10 minutes) using the excitation power supply circuit section 7.
The exhaust pump 6 is used to exhaust the air, and then the rare gas diluted halogen gas, which is a component of the laser gas, is filled in from the rare gas diluted halogen gas supply device 5 in the laser gas supply unit 4, and the halogen gas is evacuated for an appropriate period of time (about (10 minutes) Discharge is performed using the excitation power supply circuit section 7, exhaust is performed using the exhaust pump 6, and then laser gas is filled. By discharging He, impurities such as moisture and oxygen attached to the surface of the electrode 2 are thrown out into the He gas, so the impurities on the surface of the electrode 2 can be removed by exhausting after the discharge, and furthermore, the impurities on the surface of the electrode 2 can be removed. By discharging the halogen gas, the surface of the electrode 2 can be covered with halogen gas, which is a component of the laser gas, and thereafter, a chemical reaction between the surface of the electrode 2 and the halogen gas can be suppressed. After that, the laser gas is sealed in the laser container, so there is no possibility that the laser output will not be obtained in a short period of time.

The time required to restore the excimer laser is only 20 minutes for two discharges, and therefore, in the apparatus of the second embodiment, only a short time is required to restore the excimer laser.

FIG. 3 shows curves 11 and 12 representing changes in laser output depending on the number of operating shots in the excimer laser devices of the first and second embodiments, respectively. If the excimer laser has been restored, the rate of decrease in laser output due to the number of operating shots shown in FIG. 3 will be small. For comparison, Fig. 3 shows a case in which no recovery method is taken in the conventional excimer laser device shown in Fig. 4, that is, when the inside of the laser container is exposed to air and then the air is exhausted. In the conventional excimer laser device shown in FIG. A curve 14 represents the decrease in laser output due to the number of operating shots when a halogen gas diluted with a rare gas, which is a component of the laser gas supplied from the chamber 5, is sealed for a long period of 12 hours, then exhausted, and the laser gas is filled. It is shown. Comparing curve 11, curve 13, and curve 14, the excimer laser device of the first embodiment of the present invention is inferior to the conventional excimer laser device, which takes a long time of 12 hours to restore the excimer laser. It can be seen that the lost excimer laser has been restored.

Comparing curve 12, curve 13, and curve 14, the excimer laser device according to the second embodiment of the present invention has a longer recovery time than the conventional excimer laser device, which takes a long time of 12 hours to recover. It can be seen that the decrease in laser output due to the number of operating shots is small.

In this way, in the second embodiment, under the sequence control from the control unit 10 provided, Ha is first sealed in the laser container 1, discharged (for about 10 minutes), and exhausted, and then becomes a component of the laser gas. By filling in halogen gas diluted with rare gas and discharging for an appropriate time (about 10 minutes), impurities on the electrode surface can be removed, and in addition, the electrode surface can be covered with halogen gas, which is a component of the laser gas. After that, the chemical reaction between the electrode surface and the halogen gas can be suppressed. Then, since the laser gas is sealed, the laser output does not decrease in a short period of time. Therefore, in the second embodiment, only a short time is required to restore the excimer laser.

In the second embodiment, the recovery is more complete than in the first embodiment. That is, in the second embodiment, the rate of decrease in laser output during long-term operation is smaller. However, the first embodiment has the advantage that it can be done in a shorter time than the second embodiment.

In addition, as a modification of the second embodiment, the control unit 10 is configured to repeat the filling, discharging, and exhausting of Hs gas, and then the filling, discharging, and exhausting of halogen gas diluted with rare gas, which is a component of the laser gas, two or more times. Eximer laser recovery will be more complete by performing sequence control from

Note that although Us is used in the first and second embodiments described above, other rare gases (eg, Ar) can also be used in the present invention.

(Effects of the Invention) By using the present invention, an excimer laser device can be obtained in which the inside of the laser container can be restored in a short time after being exposed to air.

[Brief explanation of drawings]

1 is a block diagram of an excimer laser device according to a first embodiment of the present invention, FIG. 2 is a block diagram of an excimer laser device according to a second embodiment of the present invention, and FIG. 3 is a block diagram of an excimer laser device according to a second embodiment of the present invention. In the example, whether or not the excimer laser has been restored was determined when no measures were taken to restore the excimer laser using a conventional excimer laser device, and when it took a long time of 12 hours to restore the excimer laser using a conventional device. The graph shown in comparison with FIG. 4 is a block diagram of a conventional excimer laser device. l...laser container, 2...electrode, 3...optical window,
4... Laser gas supply section, 5... Halogen gas supply device for rare gas dilution in the laser gas supply section 4, 6... Exhaust pump, 7... Excitation power supply circuit, 8... H8 supply section,
9, 10...Control unit, 11...Curve showing the decrease in laser output due to the number of operating shots when the excimer laser is restored in the first embodiment, 12...
A curve showing the decrease in laser output due to the number of operating shots when the excimer laser is restored in the second embodiment,
13...Curve showing the decrease in laser output due to the number of shots when no method is taken to restore the excimer laser in a conventional excimer laser device, 14
. . . A curve showing the decrease in laser output due to the number of operating shots when the excimer laser is restored over 12 hours in a conventional excimer laser device. Agent Patent Attorney Nobu Honjo Bento Box Figure 1 Figure 2 Figure 4

Claims (3)

[Claims] (1) A laser container in which a laser gas is sealed, an electrode that discharges within the laser container, an excitation power supply circuit that supplies the discharge electrode with a high voltage that causes the discharge electrode to generate a discharge, and the laser container that causes the discharge to occur. A rare gas halide excimer comprising: a laser oscillation reflector that reflects laser light generated within to cause laser oscillation; and a laser gas supply/exhaust section that supplies laser gas to the laser container and exhausts the laser gas from the laser container. In the laser device, the laser device includes a rare gas supply unit that supplies a rare gas to the laser container, and a control unit that restores the inside of the laser container to a state suitable for laser oscillation after the laser container is exposed to air. ; this control section controls the first step of supplying the rare gas to the laser container by controlling the rare gas supply section after the laser container is exposed to air; and the first step of controlling the excitation power supply circuit to supply the rare gas to the laser container. a second step of causing electric discharge; a third step of controlling the rare gas supply section or the laser gas supply/exhaust section to exhaust the rare gas in the laser container; and controlling the laser gas supply/exhaust section. and a fourth step of filling the laser gas into the laser container. (2) After the third step, the control section controls the laser gas supply/exhaust section to fill the laser container with halogen gas diluted with a rare gas, which is one of the components of the laser gas. a 3B step of controlling the excitation power supply circuit to cause the discharge; and a 3C step of controlling the laser gas supply and exhaust section to exhaust the rare gas diluted halogen gas in the laser container. 2. The rare gas halide excimer laser device according to claim 1, wherein the fourth step is performed after performing the above steps sequentially. (3) The rare gas halide excimer laser device according to claim 1 or 2, wherein the rare gas is He gas.