WO1988000403A1

WO1988000403A1 - Gas laser

Info

Publication number: WO1988000403A1
Application number: PCT/JP1987/000452
Authority: WO
Inventors: Yasuhiro Nozue; Yasuo Itakura; Noritoshi Ito; Osamu Wakabayashi; Junichi Fujimoto; Masahiko Kowaka
Original assignee: Kabushiki Kaisha Komatsu Seisakusho
Priority date: 1986-06-30
Filing date: 1987-06-30
Publication date: 1988-01-14

Abstract

A capacitor (C2) that gives discharge energy to discharge electrodes (11, 12) is disposed outside a laser tube (10) which is oriented at right angles with both the direction of discharge and a resonance direction of a laser beam. One end of the capacitor is connected to the anode side of the discharge electrode, and the other end thereof to a spare electrode (16) that is arranged on the cathode side of the discharge electrode maintaining a predetermined discharge gap. This makes it possible to reduce the posterior current after discharge has taken place and to prolong the life of the circuit components. In addition to the above-mentioned structure, a gas supply hole is formed over the discharge portion of one of the main discharge electrodes, and a laser gas is injected from the gas supply hole toward the other main discharge electrode. This enables discharge to take place very efficiently and the recycling rate of the laser gas to be minimized, and makes it possible to accomplish oscillation of a high repetitive number that has been so far impossible with the conventional devices.

Description

Technical Field of Gas Laser Equipment E

The present invention relates to gas laser concealment, and more particularly to supply of gas between discharge electrodes and supply of discharge energy between discharge electrodes.

Background art

Excimer lasers have been widely developed in recent years because of their ability to oscillate with high efficiency and high output. In particular, due to their non-coherent properties, photolithographic lasers have been developed. The use for such applications is drawing attention.

As the excimer laser discharge circuit, one of the discharge electrodes ER constituting the main discharge circuit is normally the ground potential, and the other is the capacitor C of the charging circuit B, as shown in FIG. It is connected to the high-voltage DC power supply HV through 1 and the resistor R. Further, one end of a capacitor C2 for applying discharge energy is connected to one end of the discharge electrode ER, and the other end of the capacitor C2 connects a predetermined discharge gap with the other end of the discharge electrode ER. a contrast _c are Setchimaki the arranged pre-electrodes P i, the charging circuit B of the co sweep rate on both sides of the capacitor C 1 is constituted by cyclic La Bokuro emissions such as pitch SW and Lee Ndaku data Nsu Are connected in parallel with the ground potential.

In a discharge circuit with this configuration, when the switch SW is open, HV → R1 → G1 → L → ground lightning 88/00403

Capacitor C 1 is charged on the 1st 2 — circuit. Then, when the switch SW is closed, the charge of C 1 is transferred to G 2 by the LG resonance due to the floating inductance in the circuit on the path of G 1 → SW—〇 2 → ί ί → 〇 1. Is done.

Then, G 2 is charged by this charge transfer. Then, when the charging voltage of G2 becomes equal to or higher than the starting breakdown voltage of the laser material, a discharge occurs at the discharge electrode ER, and the discharge energy excites the laser material and induces laser light.

In such a discharge circuit, as the inductance of the discharge main circuit M including G 2, E, P i and the laser light material is smaller, the post-current after the start of the discharge is attenuated faster, and the stress to the circuit components is reduced. I know it can be done.

However, in the conventional discharge circuit, the capacitor C 2 was arranged in the axial direction of the laser tube in many circuits, so the cross-sectional area of the main lightning main circuit M increased and the inductance increased, resulting in a decrease in the post-current. However, there was a problem that P became long, and circuit components deteriorated quickly.

The present invention has been made in view of the above circumstances, and has as its object to improve the life of circuit components.

Another object of the present invention is to reduce the gas circulation flow rate and reduce the burden on the gas circulation device.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view showing an example of the present invention, FIG. 2 is a cross-sectional view showing a second embodiment of the present invention, and FIGS. 3 (a) and 3 (b) are drawings of the present invention. Exclusion of third implementation of invention Description of the main part of the laser device @, FIGS. 4 (a) to (d) show a modification of the first main discharge electrode of the device S, and FIG. 5 shows a modification of the gas supply unit. FIG. 6 is a diagram showing an equivalent circuit of a discharge circuit of the gas laser device.

Disclosure of the invention

Therefore, in the present invention, in a gas laser device, a capacitor that applies discharge energy to a discharge electrode is disposed outside the laser tube in a direction perpendicular to the discharge direction and perpendicular to the resonance direction of the laser light. One end is connected to the anode side of the discharge electrode, and the other end is connected to a spare electrode arranged with a predetermined discharge gap with respect to the cathode side of the discharge electrode.

That is, by disposing the capacitor outside the laser tube in a direction perpendicular to the discharge direction and perpendicular to the direction of the t-swing of the laser light, the distance between the discharge electrode and the capacitor can be reduced. Therefore, the discharge main circuit cross-sectional area as a whole decreases. As a result, the inductance becomes smaller, the post-current also becomes smaller, and the life of circuit components can be prolonged.

Further, in the present invention, in the above-described gas laser device, a small hole is formed on one surface of a discharge portion of one of the main discharge electrodes, and a laser gas is emitted from the hole into a discharge region.

With this structure, the gas is directly injected into the discharge area from one main discharge electrode to the other main discharge electrode, so that the gas deteriorated by the discharge is efficiently blown. Discharge is performed very efficiently, and the laser Since it is not necessary to circulate the gas in the spare power gap, which does not affect the performance of the vehicle, the burden on the gas circulator is reduced.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to explain the present invention in more detail, the present invention will be described in detail with reference to the drawings.

FIG. 5 is a new view showing the configuration of the discharge circuit according to the present invention, and shows a cross section of a plane orthogonal to the resonance direction of laser light. In the figure, main electrodes 11 and 12 constituting a discharge electrode ER are arranged inside a laser tube 10. The upper main electrode 11 in the figure is the anode and the lower main electrode 13 is the cathode. The main electrode 陽極 1 on the anode side is orthogonal to the laser light resonance direction (perpendicular to the paper). The laser electrode has an extension 13 extending in the direction perpendicular to the discharge direction of the discharge electrode ER on the wall side of the laser tube. One end of the discharge capacitor G 2 is connected to the extension 13. It is connected. The main electrodes 11 and 12 are provided on their opposing surfaces with a chang-type (chang: scientific instrument television, rev. Of Scientific Instruments vol. (Electrode shape reported on pages 405 to 407), and the main electrodes 12 are separated by a predetermined gap. The electrode 16 is connected between the main electrode 1 and the main electrode 11 as one wall, and the edge member 18 that forms the laser resonance chamber 17 with the main electrode 11 as one wall leaks the sealed gas in the laser resonance chamber Ί 7. The end opposite to the main electrode 12 is connected to the capacitor C 2 through the special member 9. Here, the main electrode 12 serving as the cathode is open at both ends so that the sealed gas can flow into the laser resonance chamber 17, and is connected to the outside of the laser tube 10 through a pipe. The laser gas is fed from the continuous gas circulation and circulated to be recirculated, so that the laser tube 10 can be disposed separately from a vibration source such as an air supply fan.

In this configuration, since the capacitor C2 is arranged in a direction orthogonal to the tube axis and orthogonal to the discharge direction, the main electrode 11 and the capacitor C2 can be connected with the shortest distance. For this reason, the inductance of the main electrodes 11 and 12 and the discharge main circuit including the spare electrode Ί6, the capacitor Ί3 and the laser gas is reduced.c As a result, the post-current becomes small, and the circuit components Deterioration can be suppressed.

FIG. 2 is a sectional view showing a second embodiment of the present invention, in which a laser gas is branched from both sides of a main electrode 12 serving as an anode from the upper side of a laser tube 10 to the lower side thereof. It is configured to make it happen. In this case, the main electrode Ί2 and the capacitor G2 are connected through a conductor (not shown).

In such a configuration, the same effect as the actual saturation example shown in FIG.

In FIGS. 1 and 2, reference numeral 20 denotes a sealing member for hermetically sealing the sealed gas.

FIG. 3 (a) is a cross-sectional view showing a third embodiment of the present invention. The first main discharge electrode (power source) 21 is formed in a plate shape and a large number of holes h are formed in the surface. And the laser gas is supplied into the discharge space through the hole h. Things.

In other words, this device has a plate-shaped first main discharge electrode (power source) 21 (Fig. 3 (b)) having a large number of holes h formed on the surface and a first main discharge electrode opposed to the first main discharge electrode. A second main discharge electrode (anode) 22 of the chang type arranged in the manner described above, and a gas supply unit arranged on the back side of the first main discharge electrode 1 2 3, and gas discharge sections 24 a, 24 b disposed on both sides of the second main discharge electrode 22, and disposed near the gas supply section 23. A fluorinated krypton (KrF) gas is ejected from the gas supply unit 23 through the hole h of the first main discharge electrode 1 by a member flow fan (not shown) of the gas circulation device. The gas is excited (excimer) in a discharge portion 25 formed between the first and second main discharge electrodes, and emits a laser beam when it falls to a ground state. Excimer fell based ground state in those in so that the rapidly dissociated, returns to the circulation system again occupied thereby discharging gas outlet or al.

Reference numeral 26 denotes a pre-ionization gap for uniform discharge and increasing efficiency.

In such a device, gas is supplied to the discharge section very efficiently, and gas is discharged through the gas discharge sections provided on both sides of the second main discharge electrode. Since only the gas that gives a bad effect to the air is blown away, the gas flow required for the set number of repetitions can be reduced to the minimum required degree.

The shape of the gas supply holes provided in the first main discharge electrode is not limited to the hole shown in the embodiment, but also to the shape shown in FIG. As shown in FIG. 4A, a large number of rectangular slits S1 are arranged II at predetermined intervals perpendicular to the optical axis 0 (<< 50% aperture ratio), FIG. As shown in (b), a large number of rectangular slits S2 are arranged obliquely with respect to the optical axis 0 at a predetermined interval (aperture ratio: 5096), and FIG. As shown in (1), a large number of trapezoidal slits S3 are arranged at predetermined intervals perpendicular to the optical axis 0 (aperture ratio: 50%). The width of S4 can be changed as appropriate between the center and the end (Fig. 4 (d)).

In addition, as shown in FIG. 5, the gas supply section 3 of the second main discharge electrode is composed of a reservoir 30 having a larger sectional area than the discharge surface of the electrode, as shown in FIG. Make sure that the laser gas blows out uniformly. At this time, in order to blow out the laser gas uniformly from the slit S, the total area a of the slit S needs to satisfy the following equation.

a

0. 4 ()

A

A: Reservoir cross section

Thus, the total opening area of the slit is determined according to the capacity of the reservoir.

Further, the shape of the main discharge electrode and the shape of the gas discharge portion and the like can be appropriately changed without being limited to the embodiment.

Claims

The scope of the claims

(1) The first tube installed facing each other in the laser tube

In a gas laser device in which a laser gas is emitted to the first and second discharge electrodes to cause laser oscillation,

A capacitor for applying discharge energy to the discharge electrode is disposed outside the laser tube in a direction orthogonal to the discharge direction and orthogonal to the resonance direction of the laser beam, and one end of the capacitor is connected to the anode of the discharge electrode. A gas laser device, characterized in that the other end is connected to a spare electrode arranged with a predetermined discharge gap with respect to the negative electrode side of the discharge electrode.

(2) A large number of gas supply holes are provided on the entire discharge surface of the first main discharge electrode, and a laser gas is emitted toward the second main discharge electrode via the gas supply hole. The gas laser device according to claim 1 (1), characterized in that:

(3) The gas laser device according to (2), wherein the gas supply holes are slits arranged at regular intervals along an optical axis.

(4) Each of the slits is disposed so as to be perpendicular to an optical axis.

The gas laser device according to (3).

(5) The gas laser device according to (3), wherein the slits are arranged obliquely so as to form a predetermined angle with respect to an optical axis.

(6) The first main discharge electrode has a reservoir on a back surface, and the laser gas is supplied from the reservoir to the first main discharge electrode. The gas laser device according to item (2), which is characterized in that the gas laser is emitted through a hole.