JPS6281077A - X-ray automatic pre-ionization discharge type laser - Google Patents

Abstract

PURPOSE:To automatically preionize laser gas within a space for principal discharge by means of a simple circuit without polluting the laser gas, by causing current for charging a principal discharge capacitor to flow through an X-ray generating section within a laser chamber so as to generate X rays by that current. CONSTITUTION:A storage capacitor C is charged under a high voltage for example of 30KV through a high-voltage charging terminal HV and a charging inductance L. When an element for rapidly switching high current TH is turned ON by inputting a signal into a trigger terminal TR, a high voltage is applied to an X-ray generator tube 4 within a laser chamber 8 and the X-ray generator tube 4 generates X rays, which preionizes laser gas between principal discharge electrodes 2a and 2b. Accordingly, no timing path is needed since the current charged into the capacitor for the principal discharge is used for generating X-rays. Further, the arrangement of the X-ray generator tube enclosed within the laser chamber allows the unit to have reduced dimensions and prevents the laser gas from being polluted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to preionization of discharge type lasers.

(Background of the Invention) An excimer laser, which is a type of discharge laser, requires preliminary ionization to ionize the laser gas in the discharge space where the discharge occurs before the discharge occurs between the main discharge electrodes.

As a conventional pre-ionization method, an ultraviolet automatic pre-ionization type excimer laser is known in which the space where the main discharge occurs is irradiated with ultraviolet light generated by a spark using a charging capacitor for the main discharge. .

The ultraviolet ray automatic pre-ionization type excimer laser has a structure as shown in FIGS. 3 and 4. 3 and 4 are cross-sectional views of the main structures within the laser chamber in a plane perpendicular to the longitudinal direction of the excimer laser.

FIG. 5 is a circuit diagram of the excimer laser.

In Figures 3 to 5, 8 is a laser chamber, 1 is a main discharge capacitor, 2 is a main discharge electrode, 2a is a main electrode of one pole, 2b is a main electrode of the other pole, and 3 is a conductor. 5 is an insulator, 6 is a high voltage introduction terminal made of a conductor, 12 is for generating ultraviolet rays to preliminarily ionize the laser gas between the main electric discharges 2a and 2b before the main discharge. Spark electrodes, 12a and 12b are respective IIT pins, C is a storage capacitor, L is a charging inductance, HV is a terminal to which a high voltage power supply is connected, and TH is a high current high speed switching element such as a thyratron. be. TR is a trigger terminal of the large current high speed switching element TH.

The operation of a conventional ultraviolet automatic pre-ionization type excimer laser will be explained below.

The storage capacitor C is charged with a high voltage of, for example, 30 KV through the high voltage charging terminal HV and the charging inductance L.

When a signal is input to the trigger terminal TR to turn on the high-current high-speed switching element TH, the laser chamber 8
electrode bin 12a of the spark electrode 12 for generating ultraviolet rays,
A high voltage is applied between the electrodes 12b, and at the same time as a spark is generated, ultraviolet rays are emitted between the main discharge electrodes 2a and 2b to pre-ionize the laser gas.

At this time, the spark electrode 12 for generating ultraviolet rays becomes conductive, and the voltage between the electrodes of the main discharge capacitor 1 begins to rise.

Since this voltage is equivalent to the potential difference between the main discharge electrodes 2a and 2b, the inter-electrode voltage of the supra-nuclear discharge capacitor 1 is the discharge of an excimer laser having pre-ionized laser gas between the main discharge electrodes 2a and 2b. When the starting voltage is reached, a main discharge occurs and laser light is generated.

The energy of this main discharge is mainly given by the charge stored in the main discharge capacitor 1.

In the conventional ultraviolet automatic pre-ionization type excimer laser as described above, the timing for generating ultraviolet rays is automatically determined, so a timing circuit is not required, and the circuit is simple, which is an advantage. Spark electrode 12a
, 12b is accompanied by sputtering, so a large amount of fine impurities from the electrode material stays in the laser chamber and contaminates the laser gas, shortening the life of the laser gas. It has the disadvantage that it adheres to the output window and reduces the laser light output. In addition, ultraviolet rays have weak penetrating power and the main electrodes 2a, 2
It is difficult to uniformly pre-ionize the laser gas between B and therefore it is difficult to maintain stable glow discharge, which is essential for stable laser oscillation, and localized arc discharge tends to occur, reducing laser efficiency. This has the drawback of reducing the laser output.

Moreover, for this reason, there is a drawback that it is difficult to increase the laser output by increasing the distance between the main elements 11i2a and 2b or by increasing the size of the earth dragons ff12a and 2b.

As a solution to this problem, an X-ray preionization type excimer laser as shown in the sixth tooth is known.

FIG. 6 is a sectional view perpendicular to the optical axis of the X-ray preionization type excimer laser. In Figure 6, 7 is racer'ta
l! , 8 is a laser chamber, 9 is an X-ray generation chamber, 1O is an electron gun, and 11 is a metal foil for X-ray generation.

In the conventional X-ray pre-ionization type excimer laser as described above, the laser gas inside the laser chamber 8 is not contaminated, so the life of the laser gas is longer than the above-mentioned ultraviolet automatic pre-ionization type excimer laser. Because the ray generator is installed outside the laser chamber 8, the device becomes larger, and in order to generate the X-rays just before the main discharge, a timing circuit is required, making the overall circuit of the device complex. There was a drawback.

(Object of the Invention) The object of the present invention is to solve these drawbacks and obtain an XvA automatic pre-ionization discharge type laser that automatically pre-ionizes with a simple circuit without contaminating the laser gas in the laser chamber. be.

(Summary of the invention) The present invention includes an X-ray generating section enclosed in a laser chamber,
X-rays are generated by passing a charge current to the main discharge capacitor through the X-ray generation section, and the laser gas in the space where the main discharge is performed is automatically pre-ionized without a timing circuit. This is a technical point.

(Embodiment) FIG. 1 is a sectional view of an embodiment of the present invention, and is an example in which the present invention is applied to an excimer laser.

FIG. 2 is a circuit diagram of an embodiment of the present invention.

In Fig. 1.2, the same reference numerals as in Figs. 3 to 6 indicate members having the same effect, and the explanation thereof will be omitted.

4 is a sealed X-ray generating tube, and X is an X-ray.

The operation will be explained below.

In FIG. 2, a storage capacitor C is charged with a high voltage of, for example, 30 KV through a high voltage charging terminal HV and a charging inductance L.

When the high-current high-speed switching element TH is turned on by inputting a signal to the trigger terminal TR, a high voltage is applied to the X-ray generating tube 4 in the laser chamber 8, and the
A line is generated and precipitates the laser gas between the main discharge electrodes 2a and 2b! l Ionize.

Thereafter, a short circuit occurs between the two electrodes in the X-ray generating tube 4 due to arc discharge, charge moves from the storage capacitor C to the main discharge capacitor 1, and the voltage between the electrodes of the main discharge capacitor 1 begins to rise.

Since this voltage is equivalent to the potential difference between the main discharge electrodes 2a and 2b, when this voltage reaches the discharge starting voltage of the pre-ionized laser gas, the main discharge starts and laser oscillation is performed.

The energy of the supranuclear discharge is mainly given by the charge stored in the main discharge capacitor l.

In the above embodiment, an example was shown in which the present invention was applied to an excimer laser, but the present invention is not limited thereto, and can be applied to various discharge type lasers that require preliminary ionization.

(Effects of the Invention) As described above, the present invention uses the charging current to the main discharge capacitor as the X-ray generation current, so a timing circuit is unnecessary and the circuit is simple.

Furthermore, since the X-ray generating tube is enclosed within the laser chamber, the device can be made smaller.

Since the X-ray generating tube is sealed, there is no contamination of the laser gas, and the life of the laser gas and the device is long.

In addition, since X-rays with high penetrating power are used, it is possible to uniformly pre-ionize the space between the main discharge electrodes where the main discharge occurs, resulting in a stable main discharge and a high-output laser beam. It will be done.

Furthermore, since X-rays with high penetrating power are used, the area where uniform pre-ionization is possible can be expanded, and the distance between the main discharge electrodes and the area of the main discharge electrodes can be expanded, making it possible to create a high-output laser device. It is.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the structure of an embodiment of the present invention, Fig. 2 is a circuit diagram showing a circuit of an embodiment of the invention, and Figs. 3 and 4 are conventional ultraviolet automatic pre-ionization excimer lasers. 5 is a circuit diagram showing the circuit of a conventional excimer laser with automatic ultraviolet ray pre-ionization, and FIG. 6 is a sectional view showing the structure of a conventional X-ray pre-ionization excimer laser. . (Explanation of symbols of main parts) 1- Main discharge capacitor, 2- Laser main electrode, 3.-
electrode substrate, 4--X-ray generation tube, 5--insulator, 6--high voltage introduction terminal, 7--laser power supply, 8--laser discharge chamber, 9--X-ray generation chamber, 10--electron gun, 11-Metal foil for X-ray generation, 12.-Spark electrode for pre-ionization, X-. Takashi Watanabe, Patent Attorney, Co., Ltd. Procedural Amendment (Spontaneous January//day 1, 1985, Hanyu's Lift R, 1985 Patent Application No. 220.757, 3, Case of the person making the amendment) Related Patent Applicant: Nippon Kogaku Kogyo Co., Ltd. 4, 3-2-3 Marunouchi, Chiyoda-ku, Tokyo (411), Agent 8140, 1-6-3-5 Nishi-Oi, Honbunagawa-ku, Tokyo, Subject of amendment/invention of the specification Detailed explanation column, drawing 6, contents of amendment (1) "Pre-ionization..." on page 4 of the specification, lines 3 to 5.
・・・・・・・・・・・・・Ther” is replaced by “main discharge pole 2a”
, 2b. Pre-ionized laser gas”. (2) Insert "start" next to "main discharge" on page 6, line 3 of the specification. (3) Replace Figure 2 of the drawing with the one attached to 551. that's all

Claims (1)

[Claims] In a discharge type laser equipped with a main discharge capacitor in which a pair of main discharge electrodes are provided in a laser chamber filled with laser gas, an X-ray generating section is provided in the laser chamber, By configuring the charging current to the main discharge capacitor to flow through the X-ray generating section, X-rays are irradiated into the space between the main discharge electrodes and the laser gas in the space is emitted prior to the main discharge. An X-ray automatic pre-ionization discharge type laser characterized by automatic ionization.