JPH0327583A - Discharge-excited gas laser device - Google Patents

Abstract

PURPOSE:To simply remove and recover fine particles generated by sputtering of discharge electrodes by providing a magnetic field generator for affecting a magnetic action to laser gas in a circulating step of the laser gas. CONSTITUTION:Duct collector body 5A of a magnetic duct collector 5 is mounted on a conduit 4. When discharging electrodes in a laser chamber are sputtered to generate fine particles, the particles are circulated in the conduit. When the gas is passed through a magnetic dust collector 5 in the circulating step, the particles are attracted by a magnetic field by a magnetic field generating mechanism 8, adhered to the inner wall of the body 5A or a pipe 7 to be removed from the gas.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a discharge excited gas laser device.

(Prior art) In a discharge-excited gas laser device such as an excimer laser device, a pair of discharge electrodes (made of nickel, for example) are filled with laser gas, and a glow discharge is generated between the discharge electrodes to emit laser light. It is configured to output .

In such a laser device, a fairly large current discharge is performed, and the sputtering of the electrode at this time generates fine particle impurities. When such fine particles are on the optical axis, they absorb and scatter laser light, reducing laser output.

Furthermore, if such fine particles adhere to an optical window, they not only absorb and scatter laser light, but also damage the window glass itself.

Therefore, expensive window glass must be replaced every time a certain period of time passes.

In order to remove such fine particles from the laser gas, a configuration as shown in FIG. 6 has conventionally been used. The laser chamber 1 is provided with a conduit 2 that includes the laser chamber 1 and constitutes a laser gas circulation path, and an electrostatic precipitator or filtration filter is installed in the conduit 2 along the gas flow direction. The structure is such that a dust collector 3 and a circulation pump 4 are sequentially arranged.

According to this configuration, the laser gas is introduced from the laser chamber 1 into the conduit 2 by driving the circulation pump 4 . When the introduced laser gas passes through the dust collector 3, fine particles generated by sputtering of the electrodes are removed. The laser gas from which fine particles have been removed is returned to the laser chamber 1 again.

(Problem to be solved by the invention) However, when using an electric precipitator as the precipitator 3,
Since high voltage must be used, the structure is complicated. Further, when using a dust collecting filter, this type of filter is not only extremely expensive, but also has the inconvenience of having to be replaced periodically.

This invention uses a discharge electrode made of a magnetic material to
The purpose of the present invention is to easily remove fine particles generated by discharge sputtering using a simple and inexpensive structure.

(Means for Solving the Problems) The present invention is characterized in that a magnetic field generating mechanism is provided that exerts a magnetic effect on the laser gas during the circulation process of the laser gas.

(Function) 3 - When a magnetic field acts on the laser gas during the circulation process of the laser gas, the magnetic particles contained in the gas due to sputtering of the discharge electrode,
This magnetic field attracts and removes the particles.

The magnetic field generating mechanism can be constructed extremely easily and inexpensively by using permanent magnets or the like.

(Example) An example of the present invention will be described with reference to FIG. 1 and subsequent figures. Note that parts given the same reference numerals as in FIG. 6 indicate the same or corresponding parts. FIG. 1 shows a magnetic precipitator 5 according to the present invention, and 5A is a precipitator main body, which is installed in the pipe 4 like the precipitator 3 in FIG.

A magnet 6 is installed on the outer periphery of the dust collector main body 5A. Further, a pipe 7 made of stainless steel, for example, is arranged inside, and a magnet 6 is also installed inside the pipe 7. A magnetic field generating mechanism 8 is constructed by these magnets.

The discharge electrode inside the laser chamber 1 is a Nikkei 4- It is assumed that the magnetic material is made of a magnetic material such as metal.

When this discharge electrode is sputtered to generate fine particles, the fine particles circulate through the pipe line 2 together with the laser gas.

When the laser gas passes through the magnetic precipitator 5 during this circulation process, the fine particles are attracted by the magnetic field generated by the magnetic field generating mechanism 8, adhere to the inner wall of the precipitator main body 5A or the pipe 7, and are removed from the laser gas. It becomes like this.

The embodiment shown in FIG. 2 shows a structure in which a magnetic precipitator 5 is provided on the outer wall surface of the laser chamber 1. Specifically, by arranging a magnet 6 on the outer wall surface, a magnetic field generating mechanism 8
This is what was installed. In this case laser chamber 1
must be non-magnetic.

In FIG. 2, 11 and 12 are a pair of discharge electrodes that perform discharge to generate laser light, 13 is a capacitor for discharge, 14 is a heat exchanger, and 15 is a fan for circulation.

The fine particles circulating together with the laser gas in the laser chamber 1 by the fan 5 are caused by the magnetic field generated by the magnet 6 that constitutes the magnetic field generation mechanism 8 of the magnetic precipitator 5.
It is magnetically attracted to the inner wall surface of the laser chamber 1 and removed.

The embodiment shown in FIG. 3 shows a structure in which a magnetic precipitator 5 is installed inside the laser chamber l.

FIG. 4 shows details of the magnetic field generating mechanism 8 of this magnetic precipitator 5.

In the configuration shown in FIG. 4, a plurality of magnets 6 are installed inside a pipe 16 made of a non-magnetic material.

A saucer 17 made of a non-magnetic material is disposed around half the circumference of the pipe 16 (the circumferential surface opposite to the circumferential surface on which the laser gas is blown).

In this structure as well, the magnetic field acts on the fine particles contained in the circulating laser gas, causing them to adhere to the pipe 16 and the saucer 17.

In this case, when the laser gas flows from the heat exchanger 14 side,
A droplet is formed in the upper part of the saucer 17, and the particles flying into the pool are attracted by the magnet 6. Therefore, the particles are not blown away by the refluxing laser gas, but instead remain in the saucer ↓7.

Note that when it is necessary to prevent fine particles from adhering to the optical window, a configuration as shown in FIG. 5 may be used. That is, a magnet 6 may be installed near the window glass 20 so as not to block the laser beam, and fine particles flying toward the window glass 20 may be magnetically attracted and removed.

In the above structure, if a non-magnetic material such as stainless steel is used to separate the attracted particles from the magnet, the particles can be easily recovered by removing the magnet.

(Effects of the Invention) As detailed above, according to the present invention, fine particles generated by sputtering of the discharge electrode can be easily removed and collected in a laser device using a magnetic material such as nickel for the discharge electrode. Moreover, the structure is extremely simple and can be realized at low cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the invention, FIG. 2 is a sectional view showing another embodiment of the invention, FIG. 3 is a sectional view showing yet another embodiment of the invention, and FIG. 4 is a sectional view showing another embodiment of the invention. is a perspective view of the magnetic precipitator shown in Figure 3, Figure 5 is a sectional view showing the vicinity of the optical window, and Figure 6 is a perspective view of the magnetic precipitator shown in Figure 3.
The figure is a layout diagram showing a conventional example. 5... Magnetic precipitator, 6... Magnet, 8... Magnetic field generation mechanism, 1l... Discharge electrode, 7-8

Claims (1)

[Claims] In a discharge-excited gas laser device in which a discharge electrode is made of a magnetic material, a magnetic concentrator equipped with a magnetic field generating mechanism that exerts a magnetic effect on the laser gas during the circulation process of the laser gas is provided. A discharge-excited gas laser device equipped with a dust container.