JP3069953B2 - Excimer laser equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device such as an excimer laser. 2. Description of the Related Art In an apparatus using a laser as a light source, for example, an excimer laser stepper, it is very important to keep the operation rate of the laser high. On the other hand, conventionally, when the laser has to be stopped due to maintenance or failure of the laser, the maintenance time and the repairability are improved to shorten the stop time. When 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 apparatus such as an excimer laser, which has low reliability for long-time operation and requires frequent maintenance, stopping the laser due to maintenance or repair is an important problem. It is. The stop time varies depending on the situation, and even if the repairability is improved, a long stop may be required depending on the failure. In addition, when a replacement laser device is used, in the conventional laser device, the laser head that generates the laser medium by electric discharge and the laser resonator are integrally supported, so that the replacement of the laser device is required. Each time it is necessary to adjust the optical system, the precision optical system takes a long time, and when the replacement laser device is not moved to another position without moving the stop laser, it is not at the optimum position, so the performance of the entire device May be impaired. SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has a fixed laser resonator including windows at both ends in the optical axis direction and capable of generating gas by discharge. The position of the laser head to be installed is set at least in the horizontal direction substantially perpendicular to the optical axis , at least from the outside of the machine frame, by the guide member that regulates the horizontal movement of the laser head.
The gas laser device is configured so as to be movable up to. [Work] The movement of the laser head, which is a heavy object, is performed by the moving table, so that the movement can be smoothly performed. 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 denotes an excimer laser device for generating excimer laser light. This excimer laser device 1 is a laser for determining the optical axis of the laser light. A resonator 2 and a laser head (discharge tube) 3 for generating a laser medium by electric discharge are supported independently of a machine frame 4. The laser head 3 is detachably mounted on the machine frame 4 in a direction substantially perpendicular to the optical axis. The laser resonator 2 comprises an etalon 5, a rear mirror 6 located below the laser head 3, and a front mirror 7 located above, and the laser medium excited by the laser head 3 is a laser medium. The laser beam 3 is resonated between the two mirrors 6 and 7 of the laser resonator 2 through the windows 3a and 3b at both ends in the optical axis direction, and is extracted as laser light. 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 wavelength selecting elements, or a combination thereof may be installed. Then, the laser light is applied to mirror 8, integrator 9, mirror 10,
Condenser lens 11, reticle 12, projection lens 13
Is projected onto the wafer 14 via the. The relationship between the laser head 3 and the machine frame 4 is as shown in FIGS. 2 and 3. At least two identical laser heads 3 are prepared. Moving table 15, 15a, 15b made movable with respect to
Each laser head 3 can be set on the optical axis or taken out by rotating the movable bases 15, 15a, 15b or sliding them with the guide member 16. . The moving table 15, 15a,
15b is insulated from vibration and the like. Although not shown, the laser heads 3 are each connected to an auxiliary device such as a power supply and a gas circulation device so as to be switchable. In the above configuration, when the laser head 3 set on the optical axis has to be stopped, the movable tables 15, 15a and 15b are rotated or slid to move the laser head 3 on the optical axis. The user moves outside the machine frame 4, sets another laser head 3 on the optical axis, and operates this laser head 3. As a result, the operation is restarted with a short downtime. In the above embodiment, two laser heads 3 were prepared in one laser device, and one of them was used as a spare. However, for a plurality of laser devices,
One spare laser head may be used.
The gas laser device is not limited to the vertical type, but may be a horizontal type. According to the present invention, when the operating laser head 3 is stopped due to a failure, it can be replaced with another laser head 3 immediately and the operation can be continued. It is possible to greatly reduce the decrease in the operation rate due to the stoppage of the laser device of a device using a laser device, for example, a working machine such as an 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, so that the optical system does not need to be adjusted. It is possible to supply the same laser light as before the laser head 3 was replaced,
The performance of the entire device is not impaired. In particular, in the present invention, the movement of the laser head, which is a heavy object, can be moved in the horizontal direction perpendicular to the optical axis by the guide member that regulates the horizontal deflection, so that the laser head remains in the installed posture. It is possible to move in the horizontal direction that does not oppose gravity, without blurring, window cleaning and replacement work becomes easy, and collision with optical equipment such as peripheral mirrors and wavelength selection elements when moving the laser head can be prevented, Replacement work can be done most efficiently,
The effect that the laser installation area is small and the laser becomes very compact is synergistically obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural 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 embodiment of a support portion of the laser head. FIG. 3 is a perspective view showing an embodiment of a support portion of the laser head. [Description of Signs] 1 ... Excimer laser device 2 ... Laser resonator 3 ... Laser head 3a, 3b ... Window 4 ... Machine frame 15, 15a, 15b ... Movable table 16 ... Guide member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-217383 (JP, A) JP-A-59-227183 (JP, A) JP-A 49-2268 (JP, U) JP-A 49-268 2465 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01S 3/03-3/038

Claims (1)

(57) [Claims] With respect to the fixed laser resonator, the laser head including the windows at both ends in the optical axis direction and performing gas excitation by electric discharge is guided in a direction substantially perpendicular to the optical axis by a guide member for restricting the horizontal deflection. Horizontally , at least
An excimer laser device characterized in that the excimer laser device can be moved from the outside of the machine frame to an installation position in the machine frame .