JP2000174366A - Pulse discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pulse discharge device wherewith high-frequency oscillating current is prevented from being produced in a peaking capacitor during major discharge and production of residual charge of polarity opposite to that of the charging voltage of the peaking capacitor is eliminated. SOLUTION: A saturable reactor SI3 is placed between a peaking capacitor and a discharge electrode. It is brought in the forward direction for main discharge current from the peaking capacitor, and in the blocking direction for voltages obtained by the peaking capacitor charged in the reversed polarity by the main discharge current, and the production of high-frequency oscillating currents being thereby prevented. A diode D is parallel-connected with the discharge electrode, and voltages obtained by the peaking capacitor being charged in the reversed polarity are brought in the forward direction. As a result, a high voltage is prevented from being applied to the discharge electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse discharge device which generates a laser beam such as an excimer laser device by generating a narrow and large current pulse by a pulse power supply and exciting the laser head such as an excimer laser device with the pulse. In particular, the present invention relates to a pulse discharge circuit for suppressing a high-frequency oscillating current between a peaking capacitor and a discharge electrode.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a pulse discharge device. The pulse power supply includes a pulse generation circuit 1, a charger 2, and a boosting / magnetic pulse compression circuit 3.

A pulse generator 1 initially charges a first-stage capacitor C0 for electric power by a charger 2, and controls a semiconductor switch SW to turn on the semiconductor switch SW. supplies a pulse current I ₀ to the input stage pulse transformer PT.

The boosting / magnetic pulse compression circuit 3 uses a pulse current I ₁ boosted by a pulse transformer PT to generate a capacitor C1.
The high pressure charging, and high-pressure charge the capacitor C2 to generate a pulse current I ₂ of narrow from the capacitor C1 to the capacitor C2 by saturable reactor SI1 at the charging voltage of the capacitor C1 to operate magnetic switch further capacitor When the saturable reactor SI2 operates as a magnetic switch with the charging voltage of C2, a narrow and high voltage pulse current I _L1 is supplied from the capacitor C2 to the load 4 such as an excimer laser.

The load 4 comprises a main electrode MC and a preliminary ionization electrode AC.
C, a peaking capacitor CP is provided in parallel with the discharge electrode LH, and a pulse current I
_The peaking capacitor CP is charged at a high voltage by _L1 ,
With this voltage, preliminary ionization of the gas in the chamber is obtained by the preliminary ionization electrode ACC, and the main discharge current I _R is caused to flow through the main electrode MC by this preliminary ionization to obtain laser emission.

There are various configurations of the pulse power supply. For example, the two-stage cascaded circuit of the saturable reactors SI1 and SI2 and the capacitors C1 and C2 reduces the pulse width by a magnetic pulse compression operation in each stage, and has a configuration in which the number of stages is increased as necessary. Further, there is a configuration in which a portion of the pulse transformer PT is a saturable transformer, and a configuration in which a two-stage configuration of a pulse transformer and a saturable transformer is used. Further, there is a switch using a discharge tube instead of the semiconductor switch SW.

[0007]

SUMMARY OF THE INVENTION In a conventional device,
The load 4 has a wiring inductance L between the peaking capacitor CP and the discharge electrode LH. Therefore, after the peaking capacitor voltage V _CP is charged at a high voltage and a main discharge occurs in the main electrode MC, the discharge current I _R is a series resonance circuit of the wiring inductance L, the capacitance of the peaking capacitor CP, and the discharge resistance of the discharge electrode LH. Generates a high-frequency oscillating current.

The voltage waveform of the peaking capacitor CP at this time is as shown in FIG. 3, for example. Charges of the peaking capacitor CP is after charging period (t ₀ ~t _1), to generate a rapid main discharge to the discharge electrode LH side. During this discharge period (t _{1 to} t ₂ ), after the main discharge, a high frequency vibration is accompanied by a resonance operation due to the presence of the wiring inductance L.

During this discharge period, the saturable reactor SI
Since SI1 and SI2 are saturated to the low impedance side, when the peaking capacitor CP is charged to the opposite polarity, it returns to the pulse generating circuit 1 side. This returning energy is called kickback energy. In some cases, the kickback energy is regenerated as charge of the capacitor C0 on the pulse generation circuit 1 side. In the pulse discharge device having the regenerative function, the high-frequency oscillation caused by the reactor L can be converged in a relatively short time, but the high-frequency oscillation current flowing through the discharge electrode LH cannot be completely eliminated.

Furthermore, the recovery period discharge by the discharge electrodes LH is recovered (t ₂ ~t _3), the capacitor C _P is recharged with a polarity such as waveform A ₁ and B _1. This residual charge energy changes depending on the gas state in the discharge tube of the load 4 and the like.

In the above-described discharge phenomenon, the high-frequency oscillating current between the peaking capacitor CP and the discharge electrode LH and the residual charge (waveform B _{1 having a} polarity opposite to the charging voltage of the peaking capacitor CP) increase the life of the discharge electrode. Shrink,
There is a problem that the energy generated from the discharge electrode is reduced and an unstable operation is caused.

Further, a part of the high-frequency vibration energy is consumed as heat at the discharge electrode, which causes a problem of cooling the discharge electrode and lowers the conversion efficiency between electric energy and light energy.

An object of the present invention is to provide a pulse discharge device capable of suppressing generation of a high-frequency oscillating current in a peaking capacitor during a main discharge and eliminating generation of residual charges having a polarity opposite to the charging voltage of the peaking capacitor. It is in.

[0014]

The present invention suppresses the generation of an oscillating current after the peaking capacitor is charged to the opposite polarity by providing a saturable reactor in the main discharge path from the peaking capacitor CP to the discharge electrode LH. Further, by providing a diode in parallel with the discharge electrode, the voltage applied to the discharge electrode after the peaking capacitor CP is charged to the opposite polarity is suppressed by the forward voltage of the diode. The configuration is characterized.

A pulse current is supplied from a pulse power supply to a discharge electrode such as a laser head, and the pulse current charges a peaking capacitor connected in parallel to the discharge electrode. The charging voltage reaches a discharge starting voltage of the discharge electrode. In the pulse discharge device for obtaining a main discharge current at the discharge electrode, a saturable reactor is provided between the peaking capacitor and the discharge electrode, and the saturable reactor is a main discharge current from the peaking capacitor to the discharge electrode. , A forward direction, and the peaking capacitor is turned to a blocking direction with respect to a voltage charged to a reverse polarity by the main discharge current.

A diode is provided in parallel with the discharge electrode, the diode being in a blocking direction with respect to the main discharge current and the diode being in a forward direction with respect to a voltage charged to the opposite polarity. Features.

Further, the saturable reactor is a voltage-time product that performs a saturation operation after the electric charge of the peaking capacitor charged to the opposite polarity shifts to the pulse power supply side.

[0018]

FIG. 1 is a discharge circuit diagram of a pulse discharge device showing an embodiment of the present invention. 2 is different from FIG. 2 in that a diode D is provided in parallel with the discharge electrode LH.
The saturable reactor SI3 is provided between the peaking capacitor CP and the discharge electrode LH.

The saturable reactor SI3 a forward with respect to the polarity of the main discharge current I _R flowing through the discharge electrodes LH with high pressure charging of the peaking capacitor CP (low impedance)
The magnetic reset is performed so that the current having the polarity opposite to that of the current I _R has a blocking direction (high impedance).

The diode D is a peaking capacitor C
The polarity of the main discharge current I _R flowing through the discharge electrode LH in the high-voltage charging of P is set to a blocking direction. This diode D
It is constituted by a series circuit of a plurality of diode elements so as to obtain a high withstand voltage higher than the voltage applied to the discharge electrode LH.

In the above configuration, when the peaking capacitor CP is charged at a high voltage and the main discharge current flows through the discharge electrode LH, the current I _{R in} the loop of the peaking capacitor CP → the saturable reactor SI3 → the discharge electrode LH → the wiring inductance L Flows. At this time, the saturable reactor SI
No. 3 is magnetically reset in the direction of lower impedance, and does not affect the main discharge current, so that a narrow pulse current can be obtained.

After the main discharge, the peaking capacitor C
P is charged to the opposite polarity, and the presence of the wiring inductance L causes a high-frequency oscillating current to flow between itself and the peaking capacitor CP. However, the saturable reactor SI3 has a high impedance in this current direction. Suppress current generation. The peaking capacitor C
The voltage in which P is charged to the opposite polarity is applied to the discharge electrode LH. However, since the diode D is provided in parallel with the discharge electrode LH, the voltage applied to the discharge electrode LH is reduced in the forward direction of the diode D. Layer) voltage.

Here, since the saturable reactor SI2 is saturated in the direction of lower impedance with respect to the charging voltage of the opposite polarity of the peaking capacitor CP, the electric charge of the peaking capacitor CP is reduced to the saturable reactor SI2 →
The flow shifts to the capacitor C2 through the path of the capacitor C2, and further shifts from the capacitor C2 to the capacitor C1 through the saturable reactor SI1.

Therefore, the saturable reactor SI3 is
The voltage-time product (the product of the voltage and the time that determines the time required for the saturable reactor to saturate in the reverse direction) must be set longer than the time required for the transfer of the charge from the peaking capacitor CP to the capacitor C2. Accordingly, generation of an oscillating current at the discharge electrode LH can be completely suppressed. Further, after the transfer of energy from the peaking capacitor CP to the capacitor C2 is completed, the saturation operation in the reverse direction is obtained in the saturable reactor SI3. Can be extinguished through.

From the above, according to the present embodiment, the saturable reactor SI3 can prevent the oscillating current at the discharge electrode LH even in the presence of the reactor L, and the diode D applies a high voltage to the discharge electrode LH. Can be prevented. Thus, the life of the discharge electrode can be extended, and a stable operation can be obtained while increasing the energy conversion efficiency from the discharge electrode. Further, heat generation at the discharge electrode can be reduced and the cooling device can be simplified.

In this embodiment, the diode D
Is omitted, and only the saturable reactor SI3 is provided to prevent an oscillating current from flowing to the discharge electrode.

In the above embodiments, the capacitor C
2 shows a case in which the kickback energy transferred to the C1 side does not have a function of regenerating the kickback energy. However, the kickback energy can be effectively reused by applying to a device for regenerating the capacitor C0 on the pulse generation circuit 1 side. This regenerative function includes, for example, a diode D1 and a reactor L as shown in FIG.
A series circuit of No. 1 is provided in parallel with the capacitor C0, and when the capacitor C0 is charged to the opposite polarity by kickback energy, an oscillating current is generated in the reactor L1 through the diode D1 to charge the capacitor C0 to the same polarity as at the time of the initial charge. I do.

[0028]

As described above, according to the present invention, since the saturable reactor is provided in the main discharge path from the peaking capacitor CP to the discharge electrode LH, the generation of the oscillating current after the peaking capacitor is charged to the opposite polarity. Thus, the life of the discharge electrode can be extended, stable operation can be obtained while increasing the energy conversion efficiency from the discharge electrode, and heat generation at the discharge electrode can be reduced to simplify the cooling device.

Further, since a diode is provided in parallel with the discharge electrode, the voltage applied to the discharge electrode after the peaking capacitor CP is charged to the opposite polarity can be suppressed by the forward voltage of the diode. Further, the saturable reactor is operated to be saturated after the electric charge of the peaking capacitor shifts to the pulse power supply side, so that the residual electric charge of the peaking capacitor can be eliminated, and the stable operation at the discharge electrode is further ensured.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a pulse discharge device showing an embodiment of the present invention.

FIG. 2 shows an example of a conventional pulse discharge device.

FIG. 3 is a voltage waveform example of a peaking capacitor CP.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pulse generating circuit 2 charger 3 boosting / magnetic pulse compression circuit 4 load SW semiconductor switch C0, C1, C2 capacitor SI0, SI1, SI2, SI3 saturable reactor CP peaking capacitor LH discharge electrode D, D1 ... diode L ... wiring inductance

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Higashi 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Inside the Meidensha Corporation (72) Inventor Masayuki Tani 2-1-1, Osaki, Shinagawa-ku, Tokyo Stock Company Inside the company Meidensha (72) Inventor Tadashi Shibuya 2-1-1-17 Osaki, Shinagawa-ku, Tokyo F-term in the company Meidensha 5F071 AA06 GG03 GG05 HH07 JJ02 JJ05 JJ08

Claims (3)

[Claims] 1. A pulse current is supplied from a pulse power supply to a discharge electrode such as a laser head, and a peaking capacitor connected in parallel to the discharge electrode is charged by the pulse current. A pulse discharge device that obtains a main discharge current at the discharge electrode by reaching the saturable reactor between the peaking capacitor and the discharge electrode, wherein the saturable reactor supplies a main discharge current from the peaking capacitor to the discharge electrode. A pulse discharge device wherein the discharge current is in a forward direction and the peaking capacitor is in a blocking direction with respect to a voltage charged in reverse polarity by the main discharge current. 2. A diode is provided in parallel with the discharge electrode, the diode being in a blocking direction with respect to the main discharge current and the diode being in a forward direction with a voltage charged to the opposite polarity. The pulse discharge device according to claim 1, wherein: 3. The saturable reactor is a voltage-time product that performs a saturation operation after the charge of the peaking capacitor charged to the opposite polarity shifts to the pulse power supply side. The pulse discharge device according to claim 1.