JPH09102639A - Gas laser equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of operating efficiency of a laser equipment by quickly exchanging one laser head for another when the one laser head gets out of order and stops, by mounting a laser head for gas excitation on a transfer stand, and making the head movable in the direction almost rectangular to the optical axis. SOLUTION: In an excimer laser equipment 1, a laser resonator 2 which determines the optical axis of laser light and a laser head 3 which generates laser medium by discharge are retained independently of a machine frame 4. The laser head 3 is installed on the machine frame 4 in such a manner that it can be detached in the direction rectangular to the optical axis. At least two laser heads 3 of the same type are prepared and mounted on a transfer stand which is movable to the machine frame 4. When the laser head 3 set on the optical axis must be stopped, the laser head 3 is moved outside the machine frame 4 by rotating or sliding the transfer stand. Another head 3 is set on the optical axis and operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a gas laser device such as an excimer laser.

[0002]

2. Description of the Related Art In a device using a laser as a light source, for example, an excimer laser stepper, it is very important to maintain a high operating rate of the laser. On the other hand, conventionally, when the laser has to be stopped due to maintenance or failure of the laser, maintainability and repairability are improved to shorten the stop time. If possible, a replacement laser device is prepared, and light is supplied from the replacement laser device during the stop time.

[0003]

In a gas laser device, such as an excimer laser, which is still unreliable for long-term operation and requires frequent maintenance, stopping the laser for maintenance or repair is an important problem. The stop time varies depending on the situation, and even if the repairability is improved, it may be necessary to stop for a long time depending on the failure. Further, when the laser device for replacement is used, in the conventional laser device, the laser head and the laser resonator that generate the laser medium by the discharge are integrally supported. Each time it is necessary to adjust the optical system, the precision optical system takes a long time, and if the replacement laser device is not moved to another position without moving the stop laser, the performance of the entire device is not May be damaged.

[0004]

SUMMARY OF THE INVENTION The present invention has been conceived in view of the above, and a laser head for a fixed laser resonator including windows at both ends in the optical axis direction and performing gas excitation by discharge. Is mounted on a moving table to be movable in a direction substantially perpendicular to the optical axis.

[0005]

[Operation] The movement of the heavy-weight laser head can be performed smoothly by using a moving table.

[0006]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an excimer laser stepper showing an example of use of a gas laser device. In FIG. 1, reference numeral 1 is an excimer laser device for generating excimer laser light. A resonator 2 and a laser head (discharge tube) 3 for generating a laser medium by electric discharge are independently supported by a machine frame 4. The laser head 3 is detachably attached to the machine frame 4 in a direction perpendicular to the optical axis.

The laser resonator 2 comprises an etalon 5 and a rear mirror 6 located below the laser head 3, and a front mirror 7 located above. The laser medium excited by the laser head 3 is a laser medium. The laser light is extracted as laser light by being resonated between both mirrors 6 and 7 of the laser resonator 2 through windows 3a and 3b at both ends in the optical axis direction. In this embodiment, the laser resonator 2
Although an example in which an etalon is installed is shown as an example, a plurality of etalons and gratings may be installed as the wavelength selection element, or a combination thereof may be installed. The laser light is reflected by the mirror 8, the integrator 9, the mirror 10,
Condenser lens 11, reticle 12, projection lens 13
It is projected onto the wafer 14 via the.

The relationship between the laser head 3 and the machine casing 4 is as shown in FIGS. 2 and 3, and at least two identical laser heads 3 are prepared. Mobile bases 15, 15a, 15b that are movable relative to each other
Each of the laser heads 3 is mounted on the optical axis and can be taken out by rotating or sliding the moving bases 15, 15a, 15b. The movable tables 15, 15a and 15b are insulated from vibrations and the like. Although not shown in the figure, an accessory device such as a power source or a gas circulating device is switchably connected to each of the laser heads 3.

In the above structure, when the laser head 3 set on the optical axis must be stopped, the movable bases 15, 15a, 15b are rotated or slid to move the laser head 3 on the optical axis. The laser head 3 is moved to the outside of the machine frame 4, another laser head 3 is set on the optical axis, and the laser head 3 is operated. As a result, the operation is restarted with a short rest time.

In the above embodiment, an example in which two laser heads 3 were prepared in one laser device and one of them was used as a spare was shown. However, for a plurality of laser devices,
You may make it use one spare laser head.
Further, the gas laser device is not limited to the vertical type and may be a horizontal type.

[0011]

According to the present invention, when the laser head 3 in operation fails and is stopped, the laser head 3 can be promptly replaced with another laser head 3 to continue the operation. It is possible to significantly suppress the decrease in the operating rate due to the stop of the used apparatus, for example, the laser apparatus of the working machine such as the excimer laser stepper. Further, according to the present invention, since only the laser head 3 is replaced, the laser resonator 2 does not change even when the laser device is stopped and the operation is restarted. Therefore, the adjustment of the optical system is unnecessary. The same laser light as before replacement of the laser head 3 can be supplied,
It does not impair the performance of the entire device. Particularly, in the present invention, since the movement of the heavy-duty laser head can be smoothly moved by the moving base, the replacement work of the laser head can be performed extremely quickly and easily, and an excellent gas laser device is provided. You can Further, by making the laser head movable in a direction substantially perpendicular to the laser resonator, the laser becomes very compact, the installation area of the laser in the clean room is small, and the cost is greatly reduced. Further, the replacement and cleaning of the window becomes easy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration explanatory view of an excimer laser stepper using a gas laser device according to the present invention.

FIG. 2 is a perspective view showing an example of a support portion of a laser head.

FIG. 3 is a perspective view showing an example of a supporting portion of a laser head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Excimer laser device 2 ... Laser resonator 3 ... Laser head 3a, 3b ... Window 4 ... Machine frame 15, 15a, 15b ... Moving stand

Claims (1)

[Claims] 1. A laser head, which includes windows at both ends in the optical axis direction with respect to a fixed laser resonator and which excites gas by discharge, is mounted on a moving table and moved in a direction substantially perpendicular to the optical axis. A gas laser device characterized in that it is made possible.