JP2500607B2 - Excimer laser oscillator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge-excited excimer laser oscillator, and more particularly to an excimer laser oscillator provided with a dust collector for collecting fine particles in laser gas generated by discharge.

[0002]

2. Description of the Related Art Generally, an excimer laser oscillating device of this type encloses a mixed gas of a rare gas and a halogen gas in a container as a laser gas, excites the laser gas by high-voltage pulse discharge, and supplies the generated light to the container. Laser oscillation is realized by taking it out from the optical window. In this way, since the excimer laser uses high-voltage pulse discharge,
The fine particles generated by the sputtering action on the electrode surface and the like float in the laser gas as dust, which causes the optical window to be polluted and shortens the life of the laser device.

In order to deal with this problem, a structure in which a laser gas containing dust is introduced into a dust collector called a "dust filter", dust is collected to clean the laser gas, and the laser gas is returned into the laser container again. The excimer laser oscillator that it has is also commercially available. Usually, in an excimer laser oscillator equipped with such a dust filter, when returning the cleaned laser gas, it is sprayed on the optical window provided in the laser container to prevent the window from being contaminated. In addition, USPAT.
In 5,027,366, a purified laser gas is sprayed onto a bearing mounted on a rotating shaft of a laser gas circulation fan to prevent dust from entering the bearing and prolong the life of the bearing.

[0004]

[Problems to be Solved by the Invention] However, USPA
In the conventional excimer laser oscillator disclosed in T. 5,027,366, the normal gas flow path returned from the dust filter is divided into two, one to the optical window, and the other to the gas flow path for blowing to the bearing. Each has a structure that leads.
And, compared with the optical window part where the tip of the gas flow path is almost open, the conductance is small and almost no clean gas flows into the bearing part where the tip of the gas flow path is in a state of being close to a dead end. Therefore, it is impossible to prevent the dust from entering the bearing, and the bearing is consumed by the dust, which shortens the life of the bearing.

Therefore, the present invention has been made in view of the above points, and an object of the present invention is to provide an excimer laser gas oscillating device in which the life of a rotary bearing of a fan for circulating a laser gas is extended. .

[0006]

In order to achieve this object, an excimer laser gas oscillating device according to the present invention is provided with a dust collecting device for collecting fine particles generated by sputtering of a discharge electrode. A passage for blowing a part of the laser gas cleaned by the device to the bearing of the laser gas circulation fan, a gas pool for storing the cleaned laser gas around the bearing, and the fine particles in the gas pool. And means for preventing the intrusion of the gas containing it. Further, the excimer laser gas oscillating device according to the present invention is provided with a dust collector for collecting fine particles generated in the sputtering of the discharge electrode, etc., and a part of the laser gas cleaned by this dust collecting device is used for circulating the laser gas. A flow path for blowing to the bearing of the fan, a gas reservoir for accumulating the purified laser gas around the bearing, and a gas discharge means for discharging the purified laser gas from the gas reservoir are provided.

[0007]

According to the present invention, since the conductance is increased by providing the gas reservoir, the clean gas flows into the bearing and the invasion of dust is prevented. Further, according to the present invention, since the gas discharge means for discharging the laser gas cleaned from the gas reservoir is provided, the discharged clean gas prevents dust from entering the bearing portion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a main part of a laser gas container of an excimer laser oscillator according to the present invention. In the figure, 1 is a laser gas container, 2 is a gas circulation fan, 3 is a rotating shaft of the gas circulating fan 2, 4 is a bearing of the rotating shaft 3, and 5 is a part of gas containing dust in the laser gas container 1. Is a flow path for guiding a part of the gas cleaned by the dust filter 5 to the bearing 4, and 7 is a housing forming a gas reservoir 8 provided in the peripheral portion of the bearing 4. The distance δ between the rotary shaft 3 and the housing 7 is set to 1 mm or less.

In such a structure, a part of the gas containing dust in the laser gas container 1 is guided to the dust filter 5, the dust is collected by the dust filter 5, and then the clean gas is again gas-passed through the flow path 6. Supply to the puddle 8. As described above, by providing the gas reservoir 8, the conductance is increased and a clean gas flows into the bearing 4 to prevent the gas containing the fine particles in the laser gas container 1 from entering the bearing 4, thereby Ingress of dust is prevented. In addition, as a means for preventing gas from entering the housing 7, the distance δ between the rotary shaft 3 and the housing 7 is 1 mm.
Since it is set as follows, this also prevents dust from entering the bearing 4.

FIG. 2 is a side sectional view of a main part of a laser gas container of an excimer laser oscillator showing a second embodiment of the present invention. In the second embodiment, the laser gas circulation fan 2 is used.
It is characterized in that a spiral groove 9 formed by a method of cutting a screw is provided on an outer peripheral portion located in the gas reservoir 8 of the rotating shaft 3. The spiral groove 9 is threaded such that the gas is inclined in the B direction along the spiral groove 9 with respect to the rotation direction A of the fan 2, that is, in the direction in which the gas flows into the container 1. Therefore, although not shown, a spiral groove having an opposite inclination direction is formed on the rotary shaft on the opposite side of the fan 2.

As described above, since the spiral groove 9 which is the gas discharging means for discharging the laser gas cleaned from the gas reservoir 8 into the container 1 is formed in the rotating shaft 3, the container 1 into the bearing 4 is formed. The gas containing fine particles inside is prevented from invading, which prevents invasion of dust.

FIG. 3 is a side sectional view of a main part of a laser gas container of an excimer laser oscillator showing a third embodiment of the present invention. In the third embodiment, a nozzle 11 is provided at the tip of a gas discharge channel 10 of a gas reservoir 8 and is provided in a gas-lean region C generated by a high-speed gas flow 12 at a blow-out portion of a gas circulation fan 2. The tip of the nozzle 11 is installed.
With such a configuration, a difference in static pressure occurs between the inside of the gas reservoir 8 and the inside of the high-speed gas flow 12, and due to this difference in pressure suppression, clean gas is introduced from the gas reservoir 8 into the container 1 through the nozzle 11. Is discharged to. The tip of the nozzle 11 is installed in a direction in which the high-speed gas flow 12 does not enter, that is, in a direction in which it is not affected by dynamic pressure.

[0013]

As described above, according to the present invention, a dust collector is provided for collecting fine particles generated by sputtering of the discharge electrode, and a part of the laser gas cleaned by the dust collector is collected. By providing a flow path that blows to the bearing of the laser gas circulation fan and a gas reservoir around the bearing to store the purified laser gas, the conductance increases, and the clean gas flows into the bearing and enters the bearing. The gas containing fine particles in the laser gas container is prevented from entering, which prevents dust from entering. Further, since the means for preventing the intrusion of gas into the bearing is provided, it is possible to reliably prevent the intrusion of dust into the bearing and reduce the wear of the bearing, which results in a long maintenance cycle of the bearing. The life can be extended.

Further, since the gas discharge means for discharging the purified laser gas from the gas reservoir is provided, it is possible to prevent the gas containing fine particles in the container from entering the bearing, which also prevents the gas from entering the bearing. Dust is prevented from entering.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part of an excimer laser oscillator according to the present invention.

FIG. 2 is a side sectional view of an essential part showing a second embodiment of an excimer laser oscillator according to the present invention.

FIG. 3 is a side sectional view of an essential part showing a third embodiment of the excimer laser oscillator according to the present invention.

[Explanation of symbols]

 1 Laser Gas Container 2 Laser Gas Circulation Fan 3 Rotating Shaft 4 Bearing 5 Dust Filter 6 Flow Path 8 Gas Reservoir 9 Spiral Groove 11 Nozzle 12 High Speed Gas Flow

Claims (4)

(57) [Claims] 1. An excimer laser device for generating a laser beam by performing a high-voltage pulse discharge in a mixed gas of a rare gas and a halogen gas, comprising a fan for circulating a laser gas, and collecting fine particles generated in a sputtering of a discharge electrode. In order to collect the cleaned laser gas in the vicinity of the bearing, a flow path for spraying a part of the laser gas cleaned by the dust collector to the bearing of the laser gas circulation fan, An excimer laser oscillating device comprising a gas reservoir and means for preventing the gas containing the fine particles from entering the gas reservoir. 2. An excimer laser device for generating a laser beam by performing a high-voltage pulse discharge in a mixed gas of a rare gas and a halogen gas, comprising a fan for circulating a laser gas, and collecting fine particles generated in a sputtering of a discharge electrode or the like. In order to collect the cleaned laser gas in the vicinity of the bearing, a flow path for spraying a part of the laser gas cleaned by the dust collector to the bearing of the laser gas circulation fan, An excimer laser oscillating device comprising a gas reservoir and a gas discharge means for discharging the laser gas cleaned from the gas reservoir. 3. The excimer laser oscillator according to claim 2, wherein a spiral groove is provided on an outer peripheral portion of a rotation shaft of the laser gas circulation fan as a gas discharging unit. 4. The excimer laser oscillating device according to claim 2, wherein the gas discharge means is provided with a gas discharge flow path for discharging gas from the gas reservoir, and a nozzle attached to a tip of the flow path. An excimer laser oscillating device characterized in that the tip of this nozzle is installed in a lean region of gas generated by a subsequent gas flow in the blow-out portion of the gas circulation fan.