JP2784706B2 - Gas laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device,
In particular, the present invention relates to a mechanism for preventing fouling of windows provided at both ends of a discharge chamber.

[0002]

2. Description of the Related Art In a gas laser apparatus using an active medium in a gaseous state, a gas sealed in a chamber is caused to flow between electrodes by a fan, and gas molecules are excited by discharge to form a population inversion of the laser medium. There are a CO ₂ laser and an excimer laser which return a fan after cooling a high-temperature gas with a heat exchanger.

[0003]

In the above-mentioned gas laser device, one of the factors that hinder the extension of laser oscillation life is contamination of an optical system. When a powder compound or the like generated by repeating laser oscillation adheres to the window, the light transmittance is reduced, and the laser output is reduced. As a countermeasure for this, Japanese Patent Publication No. 60-26312 and USP-
5018161 forcibly blows the gas cleaned by the filter onto the window surface, but requires a large purge flow rate in order to prevent entrainment of the laser medium gas containing dust. On the other hand, JP-A-58-18698
5 provides an inlet for the purified gas in the window area,
A gas circulation path is provided from the gas outlet of the discharge tube to the gas inlet via the electric precipitator and the pause zone, and the window is cleaned with a clean gas. Since it is installed outside, there are problems such as an increase in cavity length and a possibility of leakage from a pipe connection. Conventionally, the aperture is disposed outside the chamber, that is, on the atmosphere side, so that the aperture becomes dirty unless purged.The aperture reacts with ultraviolet light and atmospheric gas to cause deterioration or impurities, thereby contaminating surrounding optical components. Problem. The present invention has been made in view of the above-mentioned conventional problems, and does not require a large amount of purge gas to keep a window in a clean state, increases the cavity length, and possibly causes a leak from a pipe connection. It is an object of the present invention to provide a gas laser device which does not cause a problem and can prevent deterioration of the aperture.

[0004]

In order to achieve the above object, a gas laser device according to the present invention is a gas laser device, wherein a first sub-chamber and a labyrinth are installed in order from the window side on a laser light path inside a window, The labyrinth
Laser light path is included in the opening, the rate of introducing the clean laser medium gas between the labyrinth and the first sub-chamber
A gas laser device having a gas introduction opening, wherein the clean laser medium gas is introduced into the chamber through the labyrinth. Further, in the gas laser device, a second sub-chamber and a labyrinth are installed inside the window, and a clean laser medium gas is introduced to a position of the second sub-chamber separated from the window to return to a static pressure. It was introduced into the chamber via the labyrinth.

[0005]

According to the above construction, the first sub-chamber and the labyrinth are installed in order from the window side on the laser beam path inside the window, and the clean laser medium gas is supplied between the first sub-chamber and the labyrinth. After being introduced, it is decided to be introduced into the chamber through the labyrinth, and the second sub-chamber is provided inside the window, and the laser medium gas cleaned by the dust removing device is not directly introduced into the labyrinth or the inside of the window, Once introduced into the second sub-chamber and restored to the static pressure, it is introduced into the chamber via the labyrinth. Therefore, in any of the above-described configurations, a clean laser medium gas is always supplied near the inside of the window. Can be retained. Therefore, the laser medium gas containing dust does not reach the inside of the window, and the surface of the window can be kept clean without blowing a large amount of purge gas onto the window. Further, since the gas introduction path from the dust removal device to the sub-chamber is built in the side wall of the chamber, problems such as an increase in the cavity length and a possibility of leak from the pipe connection portion do not occur. Furthermore, when an aperture for shaping the laser beam is attached, the aperture is disposed in a clean laser medium gas atmosphere near the window, so that the aperture is contaminated, deteriorated, and the surrounding optical components are contaminated due to generation of impurities. Problem can be prevented.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the gas laser device according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the structure of an excimer laser device, and FIG.
It is a part enlarged view. In these figures, 1 is a chamber for filling a predetermined gas, 2 is a fan, 3 and 4 are main electrodes, 5
Is a fan drive motor, 6 is a window, 7 is a window holder, and 8 is a labyrinth. A dust filter case 9 is connected to the chamber 1, and the chamber 1 and the dust filter case 9 are provided in a dust filter inlet 10 provided substantially at the center in the optical axis direction and inside wall surfaces at both ends of the chamber 1. The gas introduction path 11 communicates with the dust filter outlets 12 provided at both ends of the dust filter case 9. In the dust filter case 9, filters 13 for a front window and a rear window are provided, respectively.

The laser medium gas flows between the main electrodes 3 and 4 by driving the fan 2, and after blowing off the gas between the main electrodes 3 and 4, the gas is cooled by a heat exchanger (not shown), and
Return to A flow is generated in the dust filter case 9 using the pressure difference generated by the fan 2, and the laser medium gas enters the dust filter case 9 from the dust filter inlet 10 and is filtered by passing through the filter 13. . The clean gas that has exited the dust filter outlet 12 passes through the gas introduction passage 11 in the chamber wall, and
As shown in (2), it enters the second sub-chamber 14 in which the labyrinth 8 is stored. The second sub-chamber 14 is provided on the laser beam path, and a buffer area B (second sub-chamber) for stabilizing the flow of the inflowing gas.
Is formed. Here, the gas restored to the static pressure passes through the labyrinth 8 and moves inside the chamber 1 without moving the clean gas remaining in the portion of the statically defined area A (the first sub-chamber 16) near the inner surface of the window 6. In the direction of the discharge region C, that is, the main electrodes 3 and 4. Therefore, the gas in the discharge region C including dust is prevented from flowing toward the window 6.

FIG. 3 is a sectional view showing the vicinity of a window of the gas laser device according to the third embodiment, wherein the aperture is mounted. The aperture 15 is provided at the bottom of the stepped hole of the window holder 7,
That is, it is attached to the boundary surface between the above-mentioned statically-determined area A (first sub-chamber 16) and the buffer area B (second sub-chamber 14). Therefore, since the aperture 15 is always in a clean laser medium gas atmosphere, problems such as contamination and deterioration do not occur by selecting the material. For example, in an excimer laser device using fluorine as a laser medium gas, good results can be obtained by using an aperture in which aluminum is plated with Ni. Further, the aperture 15 also has a function as a partition for separating the statically defined area A (first sub-chamber 16) and the buffer area B (second sub-chamber 14), and the area A (first sub-chamber 16). Can be kept more stable.

[0009]

As described above, according to the present invention, the following effects can be obtained. (1) A first sub-chamber and a labyrinth are installed in order from the window side on a laser beam path inside a laser chamber of a window , and a laser beam is contained in an opening of the labyrinth , and a clean laser medium gas is supplied to the first sub-chamber. chamber and has a laser gas inlet opening for introducing between the labyrinth, guiding the conductor inlet
It said cleaning laser medium gas inlet, of the labyrinth
Having to introduce into the chamber through the opening, the shock wave can be of Rutotomoni discharge it near the inside of the window to always stay clean laser medium gas contains dust
Weakening the effect of flowing the laser gas in the window direction
It can, therefore, can be kept rather than the laser medium gas to reach the inside of the window containing the dust, the window surface without using a large amount of purge gas to clean. (2) On the laser beam path inside the window, a sub-chamber for introducing and stabilizing the laser medium gas cleaned by the dust remover is provided, and is introduced into the chamber through the labyrinth. A clean laser medium gas can always stay in the vicinity. Therefore, the laser medium gas containing dust floating in the discharge region does not reach the inner surface of the window, and the window surface can be always kept clean without using a large amount of purge gas. (3) Since the laser medium gas introduction path from the dust removal device to the sub chamber is built in the side wall of the chamber, the cavity length can be increased.
There is no problem such as the possibility of leakage from the pipe connection. (4) When attaching an aperture for shaping a laser beam, so it was decided to arrange in clean laser medium gas atmosphere inside the vicinity of the window, fouling of the aperture, the optical component around due to degradation or impurities generated In addition, it is possible to prevent the occurrence of a problem such as contamination of the device, and does not require a purge mechanism dedicated to the aperture. Further, since the atmosphere laser medium gas in which the aperture is placed is completely dry and the gas which may cause a chemical reaction is only halogen, the material selection of the aperture becomes easy. Further, by attaching the aperture to the boundary between the static area A (first sub-chamber) and the buffer area B (second sub-chamber), the clean gas in the static area can be more stably removed. Since it can be maintained, the effect of preventing the window from being stained increases.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a structure of a gas laser device.

FIG. 2 is an enlarged view of a part P in FIG.

FIG. 3 is a cross-sectional view of the vicinity of a window of the gas laser device with an aperture attached.

[Explanation of symbols]

Reference Signs List 1 chamber 6 window 8 labyrinth 9 dust filter case 11 gas introduction path 13 filter 14 second sub-chamber 15 aperture 16 first sub-chamber 17 labyrinth opening 18 laser gas introduction opening 19 clean laser medium gas into second sub-chamber Opening to introduce
mouth

Claims (10)

(57) [Claims] 1. A gas laser device, comprising:
A first sub-chamber and a labyrinth are installed in order from the window side on the laser beam path inside the laser chamber , and the labyrinth
Laser light path is included in the opening 17, Surure introduce clean laser medium gas between the labyrinth and the first sub-chamber
Has a gas inlet opening 18, and is introduced through the inlet opening 18.
The cleaned laser medium gas is released from the labyrinth .
A gas laser device, which is introduced into a chamber through a port 17 . 2. A gas laser device, comprising:
First subchamber, the aperture, a labyrinth is placed from the window side in order in the laser beam path of the laser chamber inside the
The labyrinth opening 17 includes a laser light path , and has a laser gas introduction opening 18 for introducing a clean laser medium gas between the aperture and the labyrinth.
A gas laser device, wherein the clean laser medium gas introduced from 18 is introduced into the chamber through the labyrinth opening 17 . 3. A gas laser device, wherein a second sub-chamber is provided around a laser optical path inside a window, and has an opening 19 for introducing a clean laser medium gas into the second sub-chamber.
2. The apparatus according to claim 1, further comprising an opening for introducing the laser gas in the second sub-chamber between the first sub-chamber and the labyrinth, and introducing the laser gas into the chamber via the labyrinth. Gas laser equipment. 4. A gas laser device, wherein a second sub-chamber is provided around a laser beam path inside a window, and has an opening 19 for introducing a clean laser medium gas into the second sub-chamber.
The gas laser device according to claim 2 , further comprising an opening (18) for introducing the laser gas in the second sub-chamber between the aperture and the labyrinth, and introducing the laser gas into the chamber through the labyrinth. 5. The gas laser device according to claim 2, wherein the aperture is disposed in a clean laser medium gas atmosphere near the inside of the window. 6. The gas laser device according to claim 2, wherein the aperture shapes a laser beam. 7. The labyrinth opening has a diameter larger than the diameter of the labyrinth opening , and the diameter of the labyrinth outlet is larger than the diameter of the labyrinth opening .
7. The gas laser device according to 4, 5, or 6. 8. The gas laser device according to claim 3, wherein the labyrinth is housed inside the second sub-chamber. 9. The gas laser device according to claim 1, wherein the laser medium gas is cleaned by a dust remover. 10. The apparatus according to claim 9, wherein dust floating in the laser medium gas is removed by a dust removing device, and a laser medium gas introducing passage from the removing device to the gas introducing portion is built in a side wall of the chamber. The gas laser device as described in the above.