JPH04186684A - Narrow band excimer laser - Google Patents

Abstract

PURPOSE:To obtain an efficient narrow band laser light by constituting a discharge space which has a pair of discharge electrodes, a resonator comprising a light emitting mirror and a total reflecting mirror and a dispersion device and a specific discharged band. CONSTITUTION:Laser light 10 excited in a discharged space 12 is dispersed when it enters a dispersion device 13. When it is turned back by a total reflecting mirror 15, it is emitted from an emitting mirror 14, passing through the dispersion device 13 and the discharge space 12 once again. Since the discharge space 12 has a discharge band given by an equation, an unnecessary portion of the laser light dispersed by the dispersion device 13 is removed without inserting an aperture, thereby obtaining laser light with a narrow spectral width. This construction makes it possible to use effectively energy injected into the discharge space and take out effectively the laser light having a narrow spectral width.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a narrowband excimer laser device.

[Conventional technology]

For conventional narrowband excimer laser equipment, in 1984
``Canadian Journal of Physics'' published in July,
It is described in detail in the literature published in HYSIC5)J Vol. 63, pages 214 to 219.

The conventional narrowband excimer + described in this document
The P device is shown in FIG. This narrow band excimer laser device consists of a resonator consisting of a discharge space 12 in which laser light is excited, a dispersion element 13 to narrow the band of the laser light, an output mirror 14 and a total reflection mirror 15 to oscillate the laser light. , 1st
The first aperture 35 and the second aperture 36 are arranged as shown in the figure.

In this narrow band excimer laser device, the discharge space 1
The laser beam 10 excited in the dispersion element 13 enters the dispersion element 13, is dispersed, is reflected by the total reflection mirror 15, and is returned to the dispersion element 13. After passing through the discharge space 12, the exit mirror 1
A laser beam 10 is emitted from 4. Here, in the resonator, there is a first aperture 35 and a second aperture 35 having a width such that the Fresnel number (NF) expressed by the following equation is approximately l.
6 is inserted, unnecessary components of the laser light dispersed by the dispersion element 13 are removed, and laser light with a narrow spectrum width can be obtained.

NA=(W/2)2/(L・λ) W: Width of discharge L: Resonator length λ: Wavelength of laser light [Problem to be solved by the invention] By the way, in the conventional narrow band niximer laser device, In order to extract laser light with a narrow spectrum width, an aperture with a width smaller than the discharge width of the discharge space where the laser light is excited is inserted, so that the energy injected into the part hidden by the aperture is This has the disadvantage that it is wasted and it is difficult to extract the laser light efficiently.

An object of the present invention is to narrow the spectrum of laser light without inserting an aperture, and to efficiently control the laser light. , a pair of main discharge electrodes for exciting the laser medium, a resonator consisting of an exit mirror and a total reflection mirror for oscillating the laser beam, and a dispersion inserted into the resonator to narrow the band of the laser beam. The device is characterized by having a discharge space having a discharge width expressed by the following formula.

w≦2 (L・λ)1″ W: Width of discharge L: Resonator length λ: Wavelength of laser light Another narrowband excimer laser device has the above-mentioned dispersion The feature is that a beam expander is inserted between the element and the main discharge electrode pair.

[Effect]

In the narrowband excimer laser according to the present invention, the laser light excited in the discharge space enters the dispersion element, is reflected by the total reflection mirror, passes through the dispersion element and the discharge space again, and is emitted from the output mirror. . Here, the discharge space is
Since the discharge width is given by the following equation, unnecessary components of the laser light dispersed by the dispersion element can be removed without inserting an aperture, and laser light with a narrow spectral width can be obtained.

w≦2 (L・λ)1/2 W: Width of discharge L: Resonator length λ: Wavelength of laser light This allows the energy injected into the discharge space to be used effectively, and efficiently widens the spectral width. A narrow laser beam can be extracted.

In addition, in the narrowband excimer laser of the present invention in which a beam expander is inserted between the dispersion element and the main discharge electrode, the laser light excited in the discharge space is expanded by the beam expander and enters the dispersion element. Therefore, the resolution of the dispersive element can be improved, and laser light with a narrower spectral width can be obtained.

〔Example〕

Embodiments of the present invention will be described in detail using the drawings.

FIGS. 1(a) and 1(b) are a front view of an embodiment of a narrowband excimer laser device of the invention set forth in claim 1 (hereinafter referred to as the first invention), and FIG. - It is a sectional view in the A section.

FIGS. 2(a) and 2(b) are construction views of an embodiment of the narrow band excimer and laser device of the invention set forth in claim 2 (hereinafter referred to as the second invention) (FIG. 2(a) )) and a sectional view taken along the line A-A in (a).

The narrow band excimer laser device using the first invention shown in FIG. It is composed of a space 12, a dispersion element 13 for dispersing laser light, an output mirror 14 for oscillating the laser light, and a total reflection mirror 15. The shape of the electrodes and their spacing are set so that the discharge width satisfies the above conditions.

In the narrowband excimer laser device according to the first invention, the laser beam IO excited in the discharge space 12 is dispersed by entering the dispersion element 13, and the total reflection mirror 1
5, the dispersive element 13. The light passes through the discharge space 12 and exits from the exit mirror 14 . Here, since the discharge space 12 has a discharge width given by the following formula, unnecessary components of the laser light dispersed by the dispersion element are removed without inserting an aperture, and the laser light with a narrow spectral width is can be obtained.

w≦2 (L・λ)1″ W: Width of discharge L: Resonator length λ: Wavelength of laser light This allows the energy injected into the discharge space to be used effectively, and efficiently narrows the spectral width. Laser light can be compared.

In the narrow band excimer laser device using the second invention shown in FIG.
1, a discharge space 12 having a discharge width of 2 (L·λ)l/2 or less, and a dispersion element 13 for dispersing laser light. Output mirror 14 for oscillating laser light. Total reflection mirror 15. It consists of a beam expander 16 for expanding the laser beam 10 from the discharge space 12. The main discharge electrode shape and electrode spacing are as described above.

In the narrowband excimer laser device according to the second invention, laser light 10 excited in discharge space 12 is expanded by beam expander 16 and enters dispersion element 13 . Thereby, the resolution of the dispersion element 13 can be improved, and the laser beam 10 with a narrower spectrum width can be efficiently extracted.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to suppress a narrow spectrum laser beam without inserting an anno(-cha), thereby improving the efficiency of obtaining a narrow band laser beam. We can provide excimer laser equipment.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the narrowband excimer laser device of the first invention, FIG. 2 is a diagram showing an embodiment of the narrowband excimer laser device of the second invention, and FIG. 3 is a diagram showing an embodiment of the narrowband excimer laser device of the second invention. FIG. 2 is a diagram showing a narrowband excimer laser device. 11... Main discharge electrode bowl, 12... Discharge space, 13... Dispersion element, 14... Exit mirror, 15... All Reflector, 16...beam expander. Agent Patent Attorney Uchihara Volume l Enja 2 Sen

Claims (2)

[Claims] (1) a pair of main discharge electrodes for exciting the laser medium;
In a narrowband excimer laser device having a resonator consisting of an output mirror and a total reflection mirror for oscillating a laser beam, and a dispersion element inserted into the resonator to narrow the band of the laser beam, the following formula is used. 1. A narrow band excimer laser device characterized by having a discharge space having a discharge width as shown in FIG. w≦2(L・λ)＾1＾/＾2 w: Width of discharge L: Resonator length λ: Wavelength of laser light (2) A narrowband excimer laser device according to claim 1, wherein a beam expander is inserted between the dispersion element and the pair of main discharge electrodes.