JP2003283017A - Magnetic compression circuit and discharge excitation gas laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of a pre-pulse voltage which worsens the compression efficiency of a magnetic compression circuit and a residual voltage which exerts a bad influence on main discharge. <P>SOLUTION: The magnetic compression circuit constitutes a two-stage magnetic pulse compression circuit by a first magnetic switch SR2 and a second magnetic switch SR3. Discharge operation is executed at a prescribed repeating frequency by the switching operation of a solid-state switch SW and the pulse compression operation of the two-stepped magnetic pulse compression circuit. A reset circuit to reset the magnetic switches SR2, SR3 is provided, a reset current to be Ir=Hs×Ln/n (L is magnetic passage length and n is a number of turns of a reset winding.) is fed to the reset windings LR2, LR3 of the magnetic switches SR2, SR3 by the reset circuit, and the reset is executed so as to make an absolute value of the magnetic field strength H to become almost equal to the saturation magnetic field strength Hs. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic compression circuit and a discharge excitation gas laser device used in a discharge excitation gas laser device used for exposure.

[0002]

2. Description of the Related Art With the miniaturization and high integration of semiconductor integrated circuits, it is required to improve the resolution in a projection exposure apparatus for manufacturing the same. For this reason, the wavelength of the exposure light emitted from the exposure light source is being shortened, and as a light source for semiconductor exposure, a K having a wavelength of 248 nm from a conventional mercury lamp is used.
An rF excimer laser device is used. Furthermore, as a light source for next-generation semiconductor exposure, Ar with a wavelength of 193 nm
F excimer laser device and fluorine (F
₂ ) Gas laser devices that emit ultraviolet rays such as laser devices are promising. In the KrF excimer laser device, a mixed gas of fluorine (F ₂ ) gas, krypton (Kr) gas and a rare gas such as neon (Ne) as a buffer gas, and in the ArF excimer laser device, fluorine (F ₂ ) gas , A mixed gas of argon (Ar) gas and a rare gas such as neon (Ne) as a buffer gas, and fluorine (F ₂ ) in a fluorine (F ₂ ) laser device.
₂ ) Hundreds of KP of laser gas, which is a mixed gas of a rare gas such as helium (He) as a gas and a buffer gas
A laser gas, which is a laser medium, is excited by generating a discharge inside the laser chamber sealed with a.

Inside the laser chamber, a pair of main discharge electrodes for exciting the laser gas are arranged facing each other with a predetermined distance therebetween in the direction perpendicular to the laser oscillation direction. A high voltage pulse is applied to the pair of main discharge electrodes, and when the voltage applied between the main discharge electrodes reaches a certain value (breakdown voltage), the laser gas between the main discharge electrodes is dielectrically broken down and main discharge starts. The laser medium is excited by this main discharge. Therefore, such an exposure gas laser device performs pulse oscillation by repeating main discharge, and the emitted laser light becomes pulsed light. At present, the laser pulse repetition frequency of the laser device used for exposure is 2K.
Although it is about Hz, in recent years, a repetition frequency of 4 KHz or higher has been requested in order to increase throughput and reduce variations in exposure amount.

Next, a discharge circuit (hereinafter also referred to as a high voltage generator) in the gas laser device will be described. FIG. 4 shows an example of the discharge circuit for generating the discharge in the laser chamber and exciting the laser gas in the exposure gas laser device described above. The high-voltage pulse generation circuit of FIG. 4 is composed of a two-stage magnetic pulse compression circuit using three magnetic switches SR1, SR2, SR3 made of a saturable reactor. Magnetic switch SR1 is I
This is for reducing switching loss in the solid-state switch SW, which is a semiconductor switching element such as GBT, and is also called magnetic assist. The first magnetic switch SR2 and the second magnetic switch SR3 form a two-stage magnetic pulse compression circuit. Here, FIG. 4A is a circuit that boosts the voltage by the switching operation of the solid state switch SW and the reactor L1 for charging the capacitor C0 without using the step-up transformer, and FIG. 4B is a circuit including the step-up transformer Tr. Is an example of.

The structure and operation of the circuit will be described below with reference to FIG. The voltage of the high voltage power supply HV is a predetermined value V
It has been adjusted to in. Initially, the solid-state switch SW is on, and no voltage is applied to the series circuit of the main capacitor C0, the magnetic assist SR1, and the reactor L1. It is assumed that the internal impedance of the high-voltage power supply HV is sufficiently large, and no short circuit current flows through the solid switch SW. Solid switch S
When W is turned off, a voltage is applied from the high-voltage power supply HV to the series circuit of the main capacitor C0, the magnetic assist SR1, and the reactor L1. When the time integrated value of the voltage applied to both ends of the magnetic assist SR1 reaches a limit value determined by the characteristics of the magnetic assist SR1, the magnetic assist SR1 is saturated and the magnetic switch is turned on, and the main capacitor C0 and the magnetic assist S
A current flows through the loop of R1 and reactor L1, and the main capacitor C0 is charged. When the solid state switch SW is turned on after the charging of the main capacitor C0 is completed, the voltage applied across the solid state switch SW is mainly applied across the magnetic assist SR1. When the time integrated value of the charging voltage Vc0 of the main capacitor C0 applied to both ends of the magnetic assist SR1 reaches a limit value determined by the characteristics of the magnetic assist SR1,
The magnetic switch SR1 is saturated and the magnetic switch is turned on, and the main capacitor C0, the magnetic assist SR1, the reactor L
1. Current flows in the loop of the solid switch SW, and the main capacitor C0 is discharged. Due to the above discharge current, reactor L
Even if energy is stored in 1 and the voltage of the main capacitor C0 becomes 0, the current continues to flow and the main capacitor C0 is charged in the opposite direction. After the main capacitor C0 is charged and the solid state switch SW is turned off, the high voltage power supply H
The sum of V and the voltage charged in the capacitor C0 is applied to the capacitor C1 to charge the capacitor C1.

After this, the voltage Vc at the capacitor C1
When the time integrated value of 1 reaches a limit value determined by the characteristics of the magnetic switch SR2, the magnetic switch SR2 is saturated and the magnetic switch is turned on, and a current flows through the loop of the capacitor C1, the capacitor C2, and the magnetic switch SR3, and the capacitor C1
The electric charge stored in the capacitor is transferred and charged in the capacitor C2. Further after this, the voltage Vc2 at the capacitor C2
When the time integrated value of the magnetic switch SR3 reaches a limit value determined by the characteristics of the magnetic switch SR3, the magnetic switch SR3 is saturated and the magnetic switch is turned on.
p, a current flows through the loop of the magnetic switch SR3, the electric charge stored in the capacitor C2 is transferred, and the peaking capacitor Cp is charged. Corona discharge for preionization is performed by the dielectric tube 12 in which the first electrode 11 is inserted.
It is generated on the outer peripheral surface of the dielectric tube 12 with a point where the second electrode 13 and the second electrode 13 are in contact with each other as a base point, but as the charging of the peaking capacitor Cp progresses, the voltage Vcp thereof rises and when Vcp reaches a predetermined voltage, the corona Corona discharge occurs on the surface of the dielectric tube 12 in the preionization part. Ultraviolet rays are generated on the surface of the dielectric tube 12 by this corona discharge, and the laser gas as the laser medium between the main discharge electrodes E is preionized.

As the charging of the peaking capacitor Cp progresses further, the voltage Vcp of the peaking capacitor Cp is increased.
Rise, and when this voltage Vcp reaches a certain value (breakdown voltage) Vb, the laser gas between the main discharge electrodes E, E is dielectrically broken down to start main discharge, and the main discharge excites the laser medium, Laser light is generated. Such discharge operation is repeatedly performed by the switching operation of the solid-state switch SW and the high-voltage power supply operation, whereby pulse laser oscillation is performed at a predetermined repetition frequency.
Here, the magnetic switches SR2 and SR3 and the capacitor C
By setting the inductance of the capacitance transfer type circuit of each stage composed of 1 and C2 so as to become smaller toward the subsequent stage, a pulse compression operation is performed in which the pulse width of the current pulse flowing through each stage is gradually narrowed. That is, a strong short pulse discharge is realized between the main discharge electrodes E.

The operation of the circuit of FIG. 4 (b) is the same as that of FIG. 4 (a) except that the step-up transformer is used for boosting. That is, when the solid state switch SW is turned off, the high voltage power supply HV charges the main capacitor C0. The charging of the main capacitor C0 is completed, and the solid switch SW turns o.
n, and when the time integrated value of the charging voltage Vc0 of the main capacitor C0 applied to both ends of the magnetic assist SR1 reaches a limit value determined by the characteristics of the magnetic assist SR1, the magnetic assist SR1 is saturated and the magnetic switch is turned on, and the main capacitor C
0, the magnetic assist SR1, the inductance LL, the primary side of the step-up transformer Tr1, and the current flows through the loop of the solid switch SW. At the same time, current flows in the loop of the capacitor C1 on the secondary side of the step-up transformer Tr1 and the main capacitor C0
The electric charge stored in the capacitor is transferred and charged in the capacitor C1. Note that, here, a combination of the inductance of the circuit loop and the parasitic inductance of the main capacitor C0 is represented as the inductance L _L. Capacitor C1
Is charged, as described above, the pulse compression operation is performed by the two-stage magnetic compression circuit, and the peaking capacitor Cp is charged. Then, as described above, when the voltage Vcp reaches a certain value (breakdown voltage) Vb, the laser gas between the main discharge electrodes E and E is dielectrically broken down to start the main discharge, and the main discharge causes the laser medium to be discharged. When excited, laser light is generated.

Now, the operation of the magnetic switch will be described in more detail. (1) FIG. 5 shows the structure of the saturable reactor that constitutes the magnetic switch, and FIG. 6 shows the magnetization curve of the core of the saturable reactor that constitutes the magnetic switch. (2) First, the operating current of the core moves from the “0” point in FIG. 6 to the (5) point by the reset current flowing in the reset winding LR wound around the core. (3) When a current (excitation current) flows from the capacitor (C1 for SR2, C2 for SR3) in the preceding stage of the saturable reactor to the main winding of the core, the magnetic field strength H increases and the The operating point moves from point (5) to point (4) in FIG. 6 toward point (1). (4) When the operating point reaches (1) due to the exciting current, the magnetic flux density in the core of the saturable reactor becomes equal to or higher than the saturation magnetic flux density, and the saturable reactor is saturated. At this time, the inductance of the saturable reactor drops sharply, so that the current from the previous stage capacitor (C1 for SR2, C2 for SR3) passes through the saturable reactor in the saturated state to the capacitor for the subsequent stage (C2 for SR2). , SR3 Cp
) Flow into and charge this.

(5) The operating point of the core when the saturable reactor is saturated is that the magnetic field force H is much larger than in (1), but it moves to the smaller H side as the current decreases. Then reach point (2). At this time, since the inductance of the saturable reactor rapidly increases, the current flowing through the saturable reactor sharply decreases. The operating point when the current becomes 0 is (2), where it stops and the magnetic flux remains (residual magnetic flux). (6) Here, when the capacitor C0 of FIG. 4 is charged again with the core operating point at point (2) and the switch SW is turned on, the core operating point is in the direction from point (2) to point (1). However, since the amount of change in the magnetic flux density in this case is small, the inductance of the saturable reactor at the time of non-saturation does not become sufficiently large, and magnetic pulse compression can hardly be performed. (7) Therefore, after performing the magnetic pulse compression, magnetic reset is performed so that the operating point of the core is returned to the point (5) through the point (3) in FIG. (8) There are various methods for magnetic reset, but as one of the simplest methods, a reset winding is provided in the core, and a reset circuit that allows a direct current to flow in the opposite direction to the main winding is provided. There is a method in which a current (reset current) is supplied so that the operating point of the core becomes point (5).

[0011]

The above reset current is
Magnetic path length of core, saturation magnetic field strength (Hs), number of winding turns (t
urn number). As the reset current, a reset current such as a manufacturer's recommended value for handling the core material of the saturable reactor (for example, ferrite) is generally used. However, if the manufacturer's recommended value is used as the reset current, the absolute value of the magnetic field strength H when flowing through the reset winding is point A in FIG. 6, and is often larger than the absolute value of the saturation magnetic field strength Hs. The inventors of the present application have found that if the magnetic field strength H when flowing through the reset winding is larger than the absolute value of the saturation magnetic field strength Hs as described above, the following problems occur. Since the region from the magnetic field strength A to -Hs ((5) → (3) → (4) in Fig. 6) is the saturated region, the capacitor in the preceding stage of the saturable reactor (in the case of SR2, C1, S
In the case of R3, from C2), the current is the latter stage capacitor (SR
A current flows through C2 in the case of 2 and Cp) in the case of SR3. Hereinafter, the magnetic switch SR2 of FIG. 4 will be described as an example.

FIG. 7 shows voltage waveforms Vc1 and Vc2 applied to the capacitors C1 and C2, and the capacitor C.
1, the current waveform i1 flowing through the loop of the capacitor C2 and the magnetic switch SR2 is shown. Since the region from the magnetic field strength A to −Hs ((5) → (3) → (4) in FIG. 6) is the saturated region, the current i1 rises rapidly and the saturable reactor is saturated (see FIG. 6). (4) → (1)) It will gradually increase. Generally, the charge is transferred from the capacitor C0 to the capacitor C1.
Ideally, when the voltage Vc1 applied to the capacitor C1 becomes maximum, the saturable reactor of the magnetic switch SR2 saturates, the current i1 flows, and the voltage Vc2 applied to the capacitor C2 starts to rise. is there. However, as a matter of fact, as described above, even before the saturable reactor is saturated at the operating point of (1) in FIG.
Current is flowing through 2. Therefore, when the magnetic switch SR2 is turned on (when the saturable reactor is saturated at the operating point (1) in FIG. 6), a certain voltage (prepulse voltage) is generated in the capacitor C2. That is, the pre-pulse voltage (corresponding to the shaded area of the current waveform) before the magnetic switch SR2 is turned on by the current flowing from the magnetic field strength A to the −Hs region ((5) → (3) in FIG. 6). Occurs.

Since the pre-pulse voltage is generated and the maximum voltage of the capacitor C1 leaks to the capacitor C2 and drops, the capacitor C2 is further charged with electric charge, so that the charge transfer efficiency from the capacitor C1 to the capacitor C2 is increased. Is reduced. That is, when the voltage of the capacitor C1 shifts (leaks) to the capacitor C2, the maximum voltage of the capacitor C1 decreases and the capacitor C2 is charged. The amount of charge transfer is determined by the difference between the voltage of the capacitor C2 and the voltage of the capacitor C1. Therefore, if the voltage of the capacitor C1 leaks to the capacitor C2 as described above, the amount of charge transfer decreases, and the charge transfer efficiency increases. Is reduced. On the other hand, after the magnetic switch is turned on, the current i1 to the capacitor C2 increases, then decreases and the operating point of the saturable reactor moves toward (1) in Fig. 6 and exceeds (2). It becomes unsaturated.

Since the reset circuit causes a reset current to flow in the reset winding, the operating point of the saturable reactor reaches (2) → (3) → (5) in FIG. In this case, (2) →
In (3), the saturable reactor is in a non-saturated state, and during this period, the current of the saturable reactor of the magnetic switch SR2 continues to flow with high inductance, so that the residual voltage (area of the shaded area of the current waveform) flows in the capacitor C2. Equivalent to) remains. This residual voltage has a problem that a voltage is applied between the main discharge electrodes E and E within a short time after the occurrence of the main discharge, which adversely affects the main discharge. Such pre-pulse voltage,
The problem of residual voltage is that the step-up transformer Tr, the magnetic switch S
The same occurs in R1 and SR3. The present invention has been made to solve the above problems, and an object of the present invention is to suppress the generation of the prepulse voltage that deteriorates the compression efficiency and the residual voltage that adversely affects the main discharge. .

[0015]

In the present invention, the above problems are solved as follows. (1) In a magnetic compression circuit having a reset winding and a magnetic switch made of a saturable reactor that reversely excites the core to perform magnetic reset by causing a reset current to flow in the reset winding, When the magnetic path length of the core of the saturable reactor is Ln, the saturation magnetic field strength is Hs, the number of turns of the reset winding is n, and the reset current is Ir, the current value Ir of the reset current of the magnetic switch is expressed by the following equation. Stipulate in. Ir = Hs × Ln / n (2) The magnetic compression circuit has a reset winding, and includes a step-up transformer that reversely excites the core to perform a magnetic reset by causing a reset current to flow in the reset winding. The magnetic path length of the core of the step-up transformer is Ln, and the saturation magnetic field strength is H.
s, the number of turns of the reset winding is n, and the reset current is Ir, the current value Ir of the reset current of the step-up transformer is defined by the following formula. Ir = Hs × Ln / n (3) In the above (1) and (2), the reset switch currents Ir flowing through the magnetic switches of the respective stages, or the magnetic switches of the respective stages and the step-up transformer have equal values.
The magnetic path length Ln of each magnetic switch or each magnetic switch and the step-up transformer, the saturation magnetic field strength Hs, and the number of turns n of the reset winding are set, and the magnetic switch of each stage or the reset of the magnetic switch and the step-up transformer of each stage is set. The windings are connected in series to flow the reset current value Ir. (4) The discharge excitation gas laser device is provided with the magnetic compression circuit of the above (1) to (3). As described above, in the first to fourth aspects of the present invention, the value of the reset current flowing through the reset circuit of the magnetic switch and the step-up transformer is the absolute value of the magnetic field strength H at that time, and the saturation magnetic field strength Hs. Since the reset current is smaller than the manufacturer's recommended value so that they are almost equal, the current flows through the peaking capacitor Cp before the step-up transformer and the saturable reactor are saturated at the operating point (1) in FIG. Is almost gone. Therefore, when the magnetic switch SR3 is turned on (when the saturable reactor is saturated at the operating point of (1) in FIG. 6), almost no prepulse voltage is generated in the peaking capacitor Cp. In addition, since the current value of the saturable reactor after charge transfer does not shift to the unsaturated state while the current value is high, after charge transfer,
A large residual voltage does not remain in the next-stage capacitor. Therefore, it is possible to suppress generation of a pre-pulse voltage that deteriorates the compression efficiency of the magnetic compression circuit and a residual voltage that adversely affects the main discharge.

[0016]

FIG. 1 is a diagram showing a first embodiment of the present invention. In this embodiment, a reset circuit is provided in the discharge circuit shown in FIG. The reset current is made smaller than the above-mentioned manufacturer recommended value so that the absolute value of the magnetic field strength H at the time of reset becomes substantially equal to the saturation magnetic field strength Hs. The discharge circuit shown in FIG. 1, like the one shown in FIG. 4 (a), is a diagram showing a circuit configuration when a circuit not including a step-up transformer is applied to the present invention, and is composed of three saturable reactors. Magnetic switches SR1, SR2, and SR3, and the first magnetic switch SR2 and the second magnetic switch SR3 constitute a two-stage magnetic pulse compression circuit, and as described above, the switching operation of the solid state switch SW, The discharge operation is performed at a predetermined repetition frequency by the pulse compression operation of the two-stage magnetic pulse compression circuit.

Further, the magnetic switches SR1, SR2,
A reset circuit RC for resetting SR3 is provided, and the reset circuit RC resets the magnetic switches SR1, SR2, SR3 such that the absolute value of the magnetic field strength H becomes substantially equal to the saturation magnetic field strength Hs. .
That is, as shown in FIG. 5, the reset windings LR1, L are provided in the cores of the magnetic switches SR1, SR2, SR3.
R2 and LR3 are wound, and reset windings LR1 and L
R2 and LR3 are connected in series to the reactor L, the resistor R, and the DC power source E, and the diode D is connected in parallel to the series circuit of the resistor R and the DC power source E. Then, a reset current Ir is passed through the reset windings LR1, LR2, LR3 to reset the magnetic switches SR1, SR2, SR3. The reset current Ir is adjusted by selecting the voltage of the DC power source E and the resistance value of the resistor R.

Here, the diode D is in a blocking state against the reset current Ir, but the magnetic switches SR1 and SR
2, SR3 is in the forward direction with respect to the induced current generated during operation. Due to the diode D and the reactor L, the above-mentioned induced current does not flow into the DC power source E,
It circulates through the reset winding of the magnetic switches SR2 and SR3, the diode D, and the reactor L. That is, the DC power source E is connected to the magnetic switch S by the diode D and the reactor L.
R1, SR2 and SR3 are protected from the induced current generated during operation. In the present embodiment, the reset current I
r was determined based on the following equation (1) so that the saturation magnetic field strength of the core of the saturable reactor forming the magnetic switches SR1, SR2, SR3 would be Hs. Ir = Hs × Ln / n (1) Here, L is the magnetic path length, and n is the number of turns of the reset winding.
Normally, the magnetic field strength H when a reset current of the manufacturer's recommended value is applied to the reset windings of the magnetic switches SR1, SR2, SR3 is H> H as described in FIG.
It was s.

Further, the magnetic switches SR1, SR2, SR
Since No. 3 has a different compression ratio, the saturation magnetic field strength Hs and the magnetic path length Ln are different. Therefore, the reset windings LR1, L
The reset currents flowing through R2 and LR3 are different. Therefore,
In the past, it was general to provide a reset circuit for each magnetic switch. In this embodiment, the magnetic switches SR1,
The magnetic path S, the saturation magnetic field strength, and the number of turns of the reset winding of SR2 and SR3 are adjusted, and the magnetic switch S is adjusted by one reset circuit.
The configuration is such that R1, SR2, and SR3 can be reset. That is, the reset current Ir1 flowing through the magnetic switch SR1 is expressed by the following equation (2),
The reset current Ir2 flowing in 2 is expressed by the following equation (3), and the reset current Ir3 flowing in the magnetic switch SR3 is
It is expressed by the following equation (4). Ir1 = Hs1 × L1 / n1 (2) Ir2 = Hs2 × L2 / n2 (3) Ir3 = Hs3 × L3 / n3 (4) Here, Ir1, Ir2 and Ir3 are magnetic switches SR1, SR2 and SR3, respectively. Reset current, Hs1, H
s2 and Hs3 are magnetic switches SR1, SR2, respectively.
The magnetic path lengths of SR3, n1, n2, and n3 are the numbers of turns of the reset windings of the magnetic switches SR1, SR2, and SR3, respectively. If the magnetic path lengths Hs1, Hs2, Hs3 and the number of turns n1, n2, n3 of the reset winding are adjusted, Ir1 = Ir2
= Ir3, whereby the magnetic switches SR1, SR2, SR3 can be reset by one reset circuit.

The operation of this embodiment will be described below with reference to FIG.
The magnetic switch SR2 will be described as an example. The same applies to the magnetic switch SR3. FIG. 2 shows voltage waveforms Vc1 and Vc2 applied to the capacitors C1 and C2, and a current waveform i1 flowing in the loop of the capacitors C1 and C2 and the magnetic switch SR2 in the present embodiment. In addition, (1) to (4) of FIG.
It corresponds to (1) to (4) of. By setting the reset currents Ir2 and Ir3 of the magnetic switches SR2 and SR3 as described above, the magnetic field strength at the time of reset becomes (3) in FIG. 6, and the magnetic field strength is (3) → (4) → (1). Before the saturable reactor moves and saturates at the operating point of (1) in FIG. 6, current hardly flows through the capacitor C2 (in the case of the magnetic switch SR3, the peaking capacitor Cp). Therefore, conventionally, as shown by the dotted line in FIG. 2, when the magnetic switches SR2 and SR3 are turned on (when the saturable reactor is saturated at the operating point of (1) in FIG. 6),
The above-mentioned pre-pulse voltage is generated in the capacitor C2 and the peaking capacitor Cp, but in the present embodiment, when the magnetic switches SR2 and SR3 are turned on, almost no pre-pulse voltage is generated in the capacitor C2 and the peaking capacitor Cp (see the same figure). See the solid line).

Further, since the residual electric charge in the capacitor C1 is hardly transferred to the capacitor C2, almost no residual voltage remains in the capacitor C1 after discharging. Therefore, it is possible to prevent the efficiency of charge transfer from the capacitors C1 to C2 from decreasing. As described above, according to the present embodiment, it is possible to suppress the generation of the pre-pulse voltage that deteriorates the compression efficiency and the residual voltage that adversely affects the main discharge.

In the embodiment described above, the discharge circuit of FIG. 4A is applied to the present invention.
Applied to the discharge circuit including the step-up transformer shown in (b),
The reset circuit allows magnetic switches SR1, SR2, S
The R3 and the step-up transformer Tr1 may be reset. FIG. 3 shows the above-mentioned FIG.
The 2nd Example of this invention which applied this invention to the discharge circuit shown to (b) is shown. The discharge circuit shown in FIG. 3 is provided with a step-up transformer as in the case shown in FIG. 4 (b). The step-up transformer Tr boosts the voltage and applies it to a magnetic pulse compression circuit connected to the subsequent stage. The magnetic compression circuit is composed of three magnetic switches SR1, SR2, and SR3 each made of a saturable reactor as in the case of FIG. 1, and as described above, the switching operation of the solid state switch SW,
The discharge operation is performed at a predetermined repetition frequency by the pulse compression operation of the two-stage magnetic pulse compression circuit.

In the present embodiment, the magnetic switch S
In addition to R1, SR2 and SR3, a reset circuit RC for resetting the step-up transformer Tr1 is provided,
The reset circuit RC causes the magnetic switches SR1,
SR2, SR3 and the step-up transformer Tr are reset so that the absolute value of the magnetic field strength H becomes substantially equal to the saturation magnetic field strength Hs. That is, in the cores of the step-up transformer Tr1 and the magnetic switches SR1, SR2, SR3, the reset windings TR1, LR1, LR2, L are provided as in the case shown in FIG.
R3 is wound, and this reset winding TR1, LR
1, LR2 and LR3 are supplied with a reset current Ir so that the step-up transformer Tr1 and the magnetic switches SR1, SR2 and SR3.
To reset. The reset current Ir is selected by selecting the value of the resistor R so as to satisfy the following equation (1), as in the first embodiment. Ir = Hs × Ln / n (1) Here, Ln is the magnetic path length, and n is the number of turns of the reset winding.

In this embodiment as well, as in the first embodiment,
Step-up transformer Tr1, magnetic switches SR1, SR2, S
The magnetic path length of R3, the saturation magnetic field strength, and the number of turns of the reset winding are adjusted so that the step-up transformer Tr1 and the magnetic switches SR1, SR2, and SR3 can be reset by one reset circuit. In this embodiment, as in the first embodiment, when the magnetic switches SR2 and SR3 are turned on, almost no pre-pulse voltage is generated in the peaking capacitor Cp, and the residual charge in the capacitor C1 is transferred to the capacitor C2. There is almost nothing to do. Therefore, it is possible to prevent the charge transfer efficiency from the capacitors C1 to C2 from being lowered, and it is possible to suppress the generation of the residual voltage which adversely affects the main discharge. Furthermore, since the step-up transformer Tr1 is reset by the reset current, it is possible to suppress the generation of residual charge in the capacitor C1.

[0025]

As described above, in the present invention, the absolute value of the magnetic field strength H at that time of the value of the reset current flowing through the reset circuit of the magnetic switch and the step-up transformer becomes substantially equal to the saturation magnetic field strength Hs. As a result, almost no current flows through the peaking capacitor before the step-up transformer and the saturable reactor are saturated at the operating point (1) in FIG. Therefore, when the magnetic switch is turned on (when the saturable reactor is saturated at the operating point (1) in FIG. 6), almost no prepulse voltage is generated in the peaking capacitor. Further, since the current value of the saturable reactor after the charge transfer is not high and does not shift to the non-saturated state, a large residual voltage does not remain in the capacitor of the next stage after the charge transfer. Therefore, it is possible to suppress generation of a pre-pulse voltage that deteriorates the compression efficiency of the magnetic compression circuit and a residual voltage that adversely affects the main discharge.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing voltage waveforms Vc1 and Vc2 and a current waveform i1 according to the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration example of a discharge circuit (high-voltage pulse generator).

FIG. 5 is a diagram showing a configuration example of a saturable reactor that constitutes a magnetic switch.

FIG. 6 is a diagram showing a magnetization curve of a core of a saturable reactor that constitutes a magnetic switch.

FIG. 7: Voltage waveforms Vc1 and Vc in a conventional discharge circuit
2 is a diagram showing 2 and a current waveform i1. FIG.

[Explanation of symbols]

C0 main capacitor HV high voltage power supply SW solid state switch L1 reactor SR1, SR2, SR3 Magnetic switch LL inductance Tr1 step-up transformer C1, C2, C3 capacitors Cp peaking capacitor 11 First electrode 12 Dielectric tube 13 Second electrode E, E Main discharge electrode TR1, LR2, LR3 reset winding L reactor R resistance E DC power supply D diode

Claims (4)

[Claims] 1. A magnetic compression circuit having a reset winding and comprising a magnetic switch made of a saturable reactor for reversely exciting a core to magnetically reset the core by supplying a reset current to the reset winding. , The magnetic path length of the core of the saturable reactor of the above magnetic switch is L
When n is the saturation magnetic field strength, H is the number of turns of the reset winding, and Ir is the reset current, the current value Ir of the reset current of the magnetic switch is defined by the following equation: Ir = Hs × Ln / n A magnetic compression circuit characterized in that. 2. The magnetic compression circuit has a reset winding, and by applying a reset current to the reset winding,
When a step-up transformer that reversely excites the core to perform magnetic reset is provided, and the magnetic path length of the core of the step-up transformer is Ln, the saturation magnetic field strength is Hs, the number of turns of the reset winding is n, and the reset current is Ir. The magnetic compression circuit according to claim 1, wherein the current value Ir of the reset current of the step-up transformer is Ir = Hs × Ln / n defined by the following equation. 3. The magnetic compression circuit is provided with m stages of magnetic compression sections, and the reset current values Ir flowing through the magnetic switches of each stage, or the magnetic switches of each stage and the step-up transformer are equal. The magnetic path length Ln and the saturation magnetic field strength H of each magnetic switch or each magnetic switch and the step-up transformer are adjusted so that
s, the number of turns n of the reset winding is set, the magnetic switch of each stage, or the magnetic switch of each stage and the reset winding of the step-up transformer are connected in series, and the reset current value Ir is supplied to the series circuit. The magnetic compression circuit according to claim 1 or 2, wherein the magnetic compression circuit flows. 4. A discharge excitation gas laser device provided with the magnetic compression circuit according to claim 1, 2, or 2.