JP4094762B2 - Discharge excitation type laser equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a discharge-pumped laser apparatus using ultraviolet pre-ionization by corona discharge, and more particularly to an improvement in the laser chamber configuration of this laser apparatus.
[0002]
[Prior art]
Conventionally, dust is generated by sputtering by discharge in a chamber of this type of laser apparatus. Therefore, the fan is turned to recirculate the laser gas and the dust is removed through a filter.
[0003]
By the way, in the conventional chamber, the flow velocity of the gas may decrease at a position where the traveling direction of the laser gas flow changes. This is because the inner wall of the chamber and the rectifying plate at the position where the traveling direction of the laser gas flow changes provide a gas flow resistance.
[0004]
As described above, when the gas flow rate is lowered, dust stays in the vicinity of the main discharge space and adversely affects the discharge. Conventionally, it has been necessary to enlarge the fan provided in the chamber in order to increase the average flow rate. .
[0005]
[Problems to be solved by the invention]
As described above, in the conventional chamber, the chamber inner wall, the rectifying plate, etc. at the position where the traveling direction of the laser gas flow changes may become a resistance to the gas flow, and the gas flow velocity may decrease. Therefore, it is necessary to increase the average flow velocity of the gas flow in the chamber, and as a result, the scale of the apparatus increases and the cost increases.
[0006]
Therefore, in the present invention, the above inconvenience is solved, and the gas flow velocity is prevented from being lowered by the chamber inner wall, the rectifying plate, etc. at the position where the traveling direction of the laser gas flow is changed. It is possible to increase the average gas flow velocity without the need for conversion.
[0007]
[Means for solving the problems and effects]
In order to achieve the above object, the invention according to claim 1 is directed to a main electrode for generating a main discharge necessary for laser oscillation in a main discharge space in a main body container filled with a laser gas, and a longitudinal direction of the main electrode. A preionization electrode that is disposed on the side of the main discharge space so as to extend along the main discharge space and performs corona discharge before the main discharge to generate preionization in the main discharge space, and one direction through the main discharge space in the discharge excitation type laser device comprising a gas recirculation means for recirculating said laser gas, said body vessel interior wall surface, the surface of the portion where the flow direction changes of the laser gas, thereby causing turbulence in the laser gas I'm trying to make any one of KUBOMI, hole, or mesh .
[0008]
According to this configuration, since the inner wall portion of the main body container in which the flow direction of the laser gas to be recirculated is shaped to cause turbulence in the laser gas, the gas flow velocity is lowered in the portion in which the flow direction of the laser gas changes. And the average flow rate of the gas in the chamber can be increased. That is, it is not necessary to increase the size of the fan as in the conventional case, and the scale of the apparatus is reduced, leading to cost reduction.
[0009]
Further, according to this configuration, in consideration of an increase in the number of repetitions of pulsed laser oscillation (main discharge pitch) in the future, the amount of dust inevitably increases and dust stays in the main discharge space. It is considered that there is a possibility of affecting the next discharge. For this reason, it is inevitable that the gas flow rate in the chamber must be increased, and this is an effective means even in such a situation.
[0010]
According to a second aspect of the present invention, in the first aspect of the present invention, the first rectifying plate that guides the reflux laser gas to the main discharge space and the reflux gas that flows out from the main discharge space are disposed on the gas reflux means side. The second rectifying plate is further provided, and the surface of the first and second rectifying plates is provided with any one of a dent, a hole, and a mesh that causes a turbulent flow in the laser gas.
[0011]
According to this configuration, not only the inner wall of the main body container but also this rectifying plate can further increase the average gas flow velocity.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.
[0013]
FIG. 1 shows a sectional configuration of a laser chamber in a gas laser apparatus according to an embodiment of the present invention, and shows a laser chamber 1 used in a discharge excitation laser apparatus using ultraviolet pre-ionization by corona discharge. . FIG. 2 is a perspective view when the external housing of the chamber is removed in order to clarify the internal configuration of the laser chamber shown in FIG. The laser chamber 1 is disposed between a half mirror (MH) and a narrow band module (NH) mounted on a gas laser device, and is a portion that encloses a laser gas and generates a discharge necessary for laser oscillation. . And as a material, it is a container comprised, for example by giving nickel plating to aluminum.
[0014]
As shown in FIG. 1, the laser chamber 1 includes a charger 2 and a pulse power module 3 as a power source outside the chamber. Here, the charger 2 is a capacitor and accumulates charges necessary for discharging. The pulse power module 3 generates a discharge by generating a high-speed pulse, and excimer laser excitation requires a high-speed and high-voltage discharge, so it can operate at high speed, high current, high voltage and low impedance. A thyratron, which is a simple switching element, is used.
[0015]
In the chamber, a pair of main electrodes (cathodes) 4 and main electrodes (anodes) 5 are provided at positions that are above and below each other with the optical axes of the half mirror (HM) and the band narrowing module (NH) interposed therebetween. ing. The main electrodes 4 and 5 generate a main discharge necessary for laser oscillation in the main discharge space. The main electrode (cathode) 4 is supported by the insulator 6 and the conductor 7 at the upper center of the chamber, while the main electrode (anode) 5 is separated from the main electrode (cathode) 4 by a conductor 8 at a predetermined position. It is supported by the place. The conductor 8 is disposed on the side of the main discharge space so as to extend along the longitudinal direction of the main electrodes 4 and 5, and performs a corona discharge before the main discharge to preliminarily ionize the main discharge space. The preionized electrodes 9 and 10 to be generated are held.
[0016]
Further, in this chamber, the heat exchanger 11 that cools the laser gas sealed in the chamber and performs heat exchange, and the laser gas sealed in the chamber from the side piece of one of the preliminary ionization electrodes 9 are paired with each other. After flowing through the main discharge space A between the main electrodes 4 and 5 into the side piece of the other preliminary ionization electrode 10, heat exchange is performed by the heat exchanger 11, and then again into the main discharge space A. And a fan (blower) 12 that recirculates the laser gas so as to flow in, and the both sides of the conductor 8 in the longitudinal direction of the conductor 8, and the laser gas recirculated in the chamber to the main discharge space A between the chamber inner wall A rectifying plate 13 that guides the laser gas that has passed through the main discharge space A and a rectifying plate 14 that guides the laser gas to the heat exchanger 11 between the inner wall of the chamber is provided.
[0017]
In the present invention, the sheets 15, 16, 17 and the sheet 18, on the surface of the inner wall of the chamber and the surface of the rectifying plate at the position where the traveling direction of the laser gas changes in the path through which the laser gas recirculated by the fan 12 passes, 19 is attached to be embedded.
[0018]
The sheets 15, 16, 17 and the sheets 18, 19 are characteristic portions of the present invention, and are attached to a portion of the gas recirculation path serving as a resistance to gas flow, and cause turbulence in the laser gas recirculated in the chamber. Acts as follows.
[0019]
And the expanded block diagram of this sheet | seat 15,16,17 and the sheet | seats 18 and 19 is shown in FIG. As shown in FIG. 3, in this embodiment, for example, a sheet using aluminum as a material is provided with a large number of semicircular crumpled shapes (tempered). 3A is a view of the sheet as viewed from above, and FIG. 3B is a cross-sectional view taken along the line II of FIG. 3A. And the electroless nickel plating is given to the whole surface of this sheet | seat. Ideally, it is desirable that the diameter of the large number of holes be 3 mm and the distance between the centers of adjacent circles be 5 mm.
[0020]
Thus, in this embodiment, since the sheet having a shape that causes turbulent flow in the laser gas is embedded in a position where the traveling direction of the laser gas changes in the path through which the laser gas passes, the gas in the gas reflux path is It is possible to prevent a decrease in the gas flow rate at a position where the flow traveling direction changes, thereby increasing the average flow rate of the gas in the chamber. Further, it is not necessary to increase the size of the fan as in the conventional case, and the scale of the apparatus is reduced, leading to cost reduction.
[0021]
Further, according to this configuration, in consideration of an increase in the number of repetitions of pulsed laser oscillation (main discharge pitch) in the future, the amount of dust inevitably increases and dust stays in the main discharge space. It is considered that there is a possibility of affecting the next discharge. For this reason, it is inevitable that the gas flow rate in the chamber must be increased, and this is an effective means even in such a situation.
[0022]
3 will be described with reference to FIGS. 4 and 5 other than the shape of the sheet shown in FIG. 3, that is, a number of semicircular scums (temple processing). FIG. 4 shows a configuration in which a number of circular holes are processed on the sheet shown in FIG. 3 described above. FIG. 4A is a view of the sheet as viewed from above, and FIG. FIG. 4A is a cross-sectional view taken along the line II of FIG. FIG. 5 shows a configuration in which the above-described sheet shown in FIG. 3 is processed into a mesh (mesh) shape, and FIG.
[0023]
As described above, in the present embodiment, in addition to the configuration in which a large number of semicircular spheres (tempered) shown in FIG. 3 are provided, a number of circular holes and mesh (mesh) as described above are provided. The structure processed in this may be sufficient. In the processing, processing is performed into a shape (size) capable of causing turbulent flow so that the gas flow velocity does not decrease.
[0024]
In the above embodiment, a sheet having a shape that causes a turbulent flow in the gas flow velocity is embedded in the chamber inner wall and the surface of the rectifying plate. However, the present invention is not limited to this, and is directly The same shape as the above-described sheet may be processed on the inner wall of the chamber and the surface portion of the current plate.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cross-sectional configuration of a laser chamber in a gas laser apparatus according to an embodiment of the present invention.
2 is a diagram showing an internal configuration of a laser chamber shown in FIG.
FIG. 3 is an enlarged configuration diagram of a shape portion that causes turbulent flow.
4 is another modification of the shape portion shown in FIG.
5 is another modification of the shape portion shown in FIG.
[Explanation of symbols]
1 Laser chamber 2 Charger 3 Pulse power module 4 Main electrode (cathode)
5 Main electrode (anode)
6 Insulator 7 Conductor 8 Conductor 9 Preionization electrode 10 Preionization electrode 11 Heat exchanger 12 Fan 13 Current plate 14 Current plate 15 Sheet 16 Sheet 17 Sheet 18 Sheet 19 Sheet

Claims (2)

A main electrode for generating a main discharge necessary for laser oscillation in the main discharge space and a side of the main discharge space so as to extend along the longitudinal direction of the main electrode in a main body container filled with laser gas A preionization electrode for performing corona discharge before the main discharge to generate preionization in the main discharge space, and a gas reflux means for refluxing the laser gas in one direction through the main discharge space. In a discharge excitation laser device,
A discharge-excited laser device characterized in that any one of the inner wall surface of the main body container on which the flow direction of the laser gas changes is provided with any one of a dent, a hole, and a mesh that causes turbulence in the laser gas. . A first rectifying plate for guiding the reflux gas to the main discharge space, and a second rectifying plate for guiding the reflux gas flowing out from the main discharge space to the gas reflux means side;
2. The discharge excitation type laser device according to claim 1, wherein the surface of each of the first and second rectifying plates is provided with any one of a hollow, a hole, and a mesh that causes a turbulent flow in the laser gas.

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