JP2744347B2 - Repetitive oscillation excimer laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a repetitive oscillation excimer laser device that outputs laser light in a medium with high efficiency.

[Prior art]

FIG. 3 shows, for example, CMC Corporation, March 25, 1986.
"Spiker-Sustina" (Spiker-Su) shown in P-53, supervised by Toyoda and Murahara, "Excimer Laser Advanced Application Technology"
It is a conceptual block diagram of a stainer).
Is a main electrode for performing a discharge 7 in the medium, 2 is a main switch for catching the discharge at the main electrodes 1A and 1B (FIGS. 5 and 6), and 3 is a voltage at the start of the discharge by applying a required voltage in advance. A pre-pulse switch for catching a discharge for reducing resistance, 4 is an excitation circuit (hereinafter, referred to as a sustainer) which shifts to a discharge operation when the discharge resistance is lowered, 5 is a spiker activated by the pre-pulse switch 3, 6 Is the inductance. Next, the operation will be described. Generally, a condition of a main discharge circuit of an excimer laser is that a high excitation intensity is obtained. Circuits have been devised to achieve high voltage and high efficiency.
There is a distribution constant for LC. Further, since the resistor R limits the current and is not suitable for increasing the output, the impedance Z is reduced to obtain a high excitation intensity. FIG. 4 is an example.
Discharge current I and resistance R when main electrodes 1A and 1B start discharging
It is known that the resistance R at the time of discharge decreases exponentially with the passage of time and stabilizes around 0.1 to 0.2 ohm after a certain time. Meanwhile, the discharge current flows as a pulse. The spiker 5 in FIG. 3 is a means for increasing the efficiency of the laser so as to maximize the life of the laser with a high average output. That is, before the steady discharge is excited, the discharge is performed in advance with a small electric power, the discharge impedance is matched, the optimum state of the pulse output is prepared in advance, and immediately after that, the main switch 2 is turned on to perform the steady discharge by the sustainer 4. It is a rush. However, the main switch 2 between the sustainer 4 and the discharge field
Usually, a magnetic saturation element 8 shown in FIG. 5 and a rail gap switch 9 shown in FIG. 6 are used. The rail gap switch 9 is not suitable for repetitive operation of several hundred hertz or more, and the magnetic saturation element 8 cuts off the current from the sustainer 4 but does not cut off the high voltage, and is applied to the main electrodes 1A and 1B. Therefore, a sufficient voltage cannot be applied to the sustainer 4 from the viewpoint of self-breakdown.

[Problems to be solved by the invention]

Since the conventional repetitive oscillation excimer laser device is configured as described above, when a magnetic saturation element is used for the main switch, the voltage is as low as not to cause self-breakdown despite the need for a voltage as high as possible. Only voltage can charge the sustainer. Further, the inductance cannot be completely reduced and is not suitable for high-speed switching. Further, there is a problem that the repetitive discharge in the case of using the rail gap switch is about 1 Hz and cannot be further increased. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and completely cuts off both the voltage and current of the sustainer from the main electrode, and forms a discharge circuit with as low a inductance as possible when the main switch is turned on. It is an object to obtain a repetition oscillation excimer laser device.

[Means for Solving the Problems]

A repetitive oscillation excimer laser device according to the present invention includes a spiker that applies a high voltage between main electrodes to excite a laser medium to start discharge, and turns on and off a pre-pulse switch to uniformly discharge, and a discharge by the spiker. A sustainer for supplying energy between the main electrodes to cause a steady discharge after the start, and a plurality of modularized field-effect transistors connected between the sustainer and the main electrode and in series with the main electrode, wherein a plurality of modularized field effect transistors are arranged. And a main switch that is connected in series and parallel with no wiring and controls on / off of input of energy from the sustainer to the main electrode.

[Action]

The main switch according to the present invention is configured by arranging a plurality of modularized field effect transistors in multiple stages and connecting them in series and in parallel without wiring, so that the inductance of the main switch can be sufficiently reduced, and the spikes are used in advance. After matching the discharge with the circuit impedance, when the high voltage of the sustainer is turned on and off with the voltage and current completely cut off, the ratio of peak voltage / steady voltage becomes large and the rise of pulse discharge becomes It becomes faster and the laser output can be made more efficient.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1 and FIG. 2, the same parts as those in FIG. 3 are denoted by the same reference numerals.
(Field effect transistor) A solid state switch as a main switch, which is connected in series and parallel using one or a plurality of solid state switches such as a module, 11 is one thyratron capable of high-speed response, Or, a thyratron switch as a main switch connected in parallel. Next, the operation will be described. The operation of the whole circuit is the same as that of the conventional example, and the description is omitted. The solid-state device switch 10 shown in FIG. 1 has a configuration in which modules as high-voltage switches are connected in series and parallel (for example, multi-stage products, no wiring) to achieve impedance matching.
As a pre-pulse effect of the spiker 5 shown in the figure, the discharge resistance R has already reached the minimum. Since the solid state switch 10 is turned on in this optimum state, the ratio of peak voltage / steady state voltage becomes large, and the rise of discharge becomes faster. When the thyratron switch 11 shown in FIG. 2 is used, a single thyratron has a high inductance because a local current flows during discharging. In order to reduce the inductance as much as possible, a plurality of thyratrons are connected in parallel to form a thyratron switch 11. As described above, the discharge efficiency is improved by matching the circuit impedance at the time of discharging, and a high-speed response is enabled.

【The invention's effect】

As described above, according to the present invention, since the main switch is configured by arranging a plurality of modularized field-effect transistors in multiple stages and connecting them in series and in parallel without wiring, it is possible to sufficiently reduce the inductance of the main switch. While you can
The ratio of peak voltage / steady-state voltage becomes large, the rise of pulse discharge is accelerated, and the laser output can be made more efficient.

[Brief description of the drawings]

FIGS. 1 and 2 are spider-sustainer circuit diagrams according to one embodiment of the present invention, FIGS. 3, 5, and 6 are conventional spiker-sustainer circuit diagrams, and FIG. FIG. 4 is a diagram illustrating a correlation between discharge current and resistance of an electrode. In the figure, 1A and 1B are main electrodes, 2 is a main switch, 3 is a pre-pulse switch, 4 is a sustainer, 5 is a spiker, 10
Denotes one or more solid state switches as a main switch, and 11 denotes one or more thyratron switches as a main switch. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-304683 (JP, A) JP-A-63-316491 (JP, A) JP-A-63-228783 (JP, A) JP-A 64-64 28980 (JP, A) JP-A-2-7484 (JP, A)

Claims (1)

(57) [Claims] 1. A spiker for applying a high voltage between main electrodes to excite a laser medium to start a discharge, turning on / off a pre-pulse switch to uniformly discharge, and a steady discharge after the spiker starts discharging. A sustainer for applying energy between the main electrodes, and a plurality of modularized field-effect transistors connected between the sustainer and the main electrode and in series with the main electrode, arranged in multiple stages, and directly connected without wiring. A repetitive oscillation excimer laser device comprising: a main switch connected in parallel to control on / off of input of energy from the sustainer to the main electrode.