JP2003250279A - Regenerative circuit of high voltage pulse generating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve regeneration efficiency by regenerating reflection energy caused by load impedance mismatching at a main capacitor without any remaining electric charge. <P>SOLUTION: A primary side of a regenerative transformer Tr2 is connected in parallel to a capacitor C1, and a diode D4 and a magnetic switch SR4 are connected in series with a secondary side of the regenerative transformer Tr2, while connected in parallel to a main capacitor C0. When a solid switch SW is turned on to saturate a magnetic assist SR1, electric charge transits from the main capacitor C0 to the capacitor C1 while transiting in pulse-compression to charge a peaking capacitor CP. When discharging starts, a current shifts in an opposite direction under a reflection energy so that the capacitor C1 is discharged in opposite direction. The electric charge charged in the capacitor C1 shifts to the main capacitor C0 through the regenerative transformer Tr2, and the main capacitor C0 is charged in the same polarity as initial charging. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerative circuit for utilizing, in a high voltage generator used for an exposure gas laser device or the like, reflected energy generated by impedance mismatch as energy for the next pulse generation. Regarding

[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 a rare gas such as argon (Ar) gas and neon (Ne) as a buffer gas, and fluorine (F ₂ ) in a fluorine (F ₂ ) laser device.
₂ ) Several hundred 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 required in order to increase throughput and reduce variations in exposure amount.

In the above exposure gas laser device,
FIG. 10 shows an example of a high-voltage pulse generator (hereinafter also referred to as a discharge circuit) for generating a discharge in the laser chamber and exciting a laser gas as described above.
The discharge circuit of FIG. 10 is composed of a two-stage magnetic pulse compression circuit using three magnetic switches SR1, SR2, and SR3 made of a saturable reactor. Magnetic switch SR1 is IG
Solid-state switch S which is a semiconductor switching element such as BT
It is a magnetic switch for reducing switching loss at W, and is usually also called magnetic assist (hereinafter referred to as magnetic assist). The first magnetic switch SR2 and the second magnetic switch SR3 form a two-stage magnetic pulse compression circuit. The configuration and operation of the circuit will be described below with reference to FIG. First, the voltage of the high voltage power supply HV is a predetermined value Vin
And the main capacitor C0 is charged. At this time, the solid state switch SW is off. When the charging of the main capacitor C0 is completed and the solid state switch SW is turned on, the voltage applied to both ends of the solid state switch SW is mainly applied to both ends of the magnetic assist SR1. Magnetic assist SR1
When the time integrated value of the charging voltage V0 of the main capacitor C0 applied to both ends of the main capacitor C0 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, the magnetic assist SR1,
A current flows through the inductance LL, the primary side of the step-up transformer Tr1, and the loop of the solid switch SW. At the same time, a current flows in the loop of the capacitor C1 on the secondary side of the step-up transformer Tr1, the electric charge stored in the main capacitor C0 is transferred, and the capacitor C1 is charged. In addition, here, a combination of the inductance of the circuit loop and the parasitic inductance of the main capacitor C0 is represented as the inductance LL.

After this, the voltage V1 across the capacitor C1
When the time integrated value of reaches a limit value determined by the characteristics of the magnetic switch SR2, the magnetic switch SR2 saturates to turn on the magnetic switch, and a current flows in the loop of the capacitor C1, the capacitor C2, and the magnetic switch SR3, and is stored in the capacitor C1. The generated electric charge is transferred and charged in the capacitor C2. Further thereafter, when the time integrated value of the voltage V2 in the capacitor C2 reaches a limit value determined by the characteristics of the magnetic switch SR3, the magnetic switch SR3 saturates and the magnetic switch is turned on, and the capacitor C2 and the peaking capacitor C
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 and the second electrode 1.
Dielectric tube 1 based on the point of contact with 3
2 occurs on the outer peripheral surface of the corona precharger Cp, but its voltage Vp rises as the charging of the peaking capacitor Cp progresses, and when Vp reaches a predetermined voltage, the dielectric tube 12 of the corona preionization section 12
Corona discharge occurs on the surface. Ultraviolet rays 6 are generated on the surface of the dielectric tube 12 by this corona discharge, and the laser gas 2 as a laser medium between the main discharge electrodes E is preionized. As the charging of the peaking capacitor Cp progresses further, the voltage Vp of the peaking capacitor Cp rises, and this voltage Vp has a certain value (breakdown voltage) V.
When reaching b, the laser gas between the main discharge electrodes E is dielectrically broken down to start the main discharge, the main discharge excites the laser medium, and 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, SR3 and the capacitor C1,
By setting the inductance of the capacitance transfer type circuit of each stage configured by C2 to become smaller toward the subsequent stage, pulse compression operation is performed such that the pulse width of the current pulse flowing through each stage is gradually narrowed, Main discharge electrodes E, E
In the meantime, a strong discharge with a short pulse is realized.

The above discharge circuit has the following problems. FIG. 11 and FIG. 10 show the capacitor C2 in the discharge circuit.
3 shows voltage waveforms of the voltage V2 applied to the peaking capacitor Cp and the voltage Vp applied to the peaking capacitor Cp. Generally, in the case of a discharge excitation type gas laser device, since the discharge impedance is small between the discharge impedance between the main discharge electrodes E and E and the peaking capacitor Cp, impedance mismatch occurs and the reflected energy causes the magnetic pulse compression circuit. A vibration is generated that travels in the reverse direction and in the forward direction. That is, after discharging in the discharge circuit of FIG. 10, a voltage oscillation occurs due to impedance mismatching as shown in FIG. 11, the voltage Vp of the peaking capacitor Cp is inverted and a reverse voltage is generated, and Cp → SR3 → C2. A current flows in the loop of and the reverse voltage is generated in the capacitor C2. Then, similarly, a current flows in the loop of C2 → SR2 → C1 and a reverse voltage is generated in the capacitor C1. Then again capacitor C1
The voltage applied to V is inverted, and a current flows in the forward direction of capacitor C1 → capacitor C2, capacitor C2 → peaking capacitor Cp. As described above, the current oscillates in the magnetic pulse compression circuit in the power supply device.

Further, as shown in FIG. 11, a capacitor in the preceding stage of the peaking capacitor Cp (in the case of FIG. 10, C
Since the discharge between the main discharge electrodes E, E often starts during the charging of the peaking capacitor Cp from 2), the charge remaining in the capacitor (C2 in the case of FIG. 10) in the preceding stage of the peaking capacitor Cp is the main discharge. A reverse voltage is generated in the capacitor (C2 in the case of FIG. 10) preceding the peaking capacitor Cp by flowing between the electrodes E. The electric charge generated at this time is reflected energy, and vibration is generated in the magnetic pulse compression circuit in the reverse direction and in the forward direction as in the case of the impedance mismatch described above. Due to the above-mentioned vibration, a voltage is applied between the main discharge electrodes E, E within a short time after the main discharge is generated, and there is a problem that the main discharge is adversely affected.

Various circuit configurations have been proposed in order to avoid the problem of vibration through the magnetic pulse compression circuit of the reflected energy as described above. FIG. 12 shows an example of the configuration of a discharge circuit of a gas laser device having a circuit for processing charges generated by a reverse voltage with a resistor. In FIG. 12,
A series circuit including a diode D1 and a resistor R is connected in parallel with the capacitor C1 having the circuit configuration of FIG. The direction of the arrow shown in FIG. 12 indicates the direction of current flow when a reverse voltage is generated in the capacitor C1. As described above, in the circuit shown in FIG. 3, the current flowing when the reverse voltage is generated is consumed by the resistor R, so that the voltage is applied between the main discharge electrodes E and E within a short time after the main discharge. To be prevented. On the other hand, in order to generate a discharge between the main discharge electrodes E, E, the solid switch SW is closed to close the main capacitor C.
When the charge is transferred from 0 to the capacitor C1, the current flows in the direction opposite to the direction of the arrow, that is, in the direction opposite to the diode D1. Therefore, the current does not flow into the series circuit including the diode D1 and the resistor R, and is not consumed by the resistor R. However, since the current generated by the reverse voltage is processed by the resistor, heat is generated in the resistor and the amount of heat generated from the laser device increases. Therefore, there is a problem that a large-scale cooling structure is required and the device becomes large. Further, since the current generated by the reverse voltage is consumed as heat, there is a problem that the current consumption of the entire laser increases.

In order to avoid the above problems, FIG.
Some circuits have been proposed that regenerates the energy flowing for the next pulse generation instead of consuming the current flowing when a reverse voltage is generated as in the circuit configuration of 1. above. 13 and 14 show configuration examples of a discharge circuit of a gas laser device having a regenerative circuit configuration for energy regeneration. In the circuit configuration of FIG. 13, an intermediate tap is provided on the primary side of the step-up transformer TR1, a series circuit of an inductance LL, a magnetic assist SR1 and a main capacitor C0 is arranged at the intermediate tap, and a solid-state switch SW is provided at one end of the primary winding. And a diode D2 at the other end. In the circuit configuration of FIG. 13, the solid state switch SW is opened, for example, at the time when the electric charge charged in the main capacitor C0 has finished transferring to the capacitor C1. After discharging, the reflected energy that is transferred while extending the pulse width is charged in the capacitor C1 so that a reverse voltage is generated in the capacitor C1. Solid switch SW
Is in the off state, the current when the reverse voltage is generated in the capacitor C1 passes through the step-up transformer TR1 as shown in FIG.
0 flows in the direction of the arrow, and reversely shifts so as to charge the main capacitor C0 in the forward direction. In this way, the reflected energy is regenerated in the main capacitor C0. The solid switch SW is turned on to generate a discharge between the main discharge electrodes E, E.
Then, when the charge is transferred from the main capacitor C0 to the capacitor C1, a voltage is applied to the reverse side of the diode D2, so that the current does not flow through the diode D2 and moves to the capacitor C1 via the step-up transformer TR1.

Further, in the circuit configuration of FIG. 14, a series circuit including an inductance L1 and a diode D2 is connected in parallel with the main capacitor C0. Figure 1
In the circuit configuration of 4, the solid state switch SW is, for example,
The reflected energy turns off when the reverse charging of the main capacitor C0 ends. The OFF timing is a period until the main capacitor C0 is recharged in the forward direction. During that time, the magnetic assist SR1 does not saturate, so that it does not flow toward the solid state switch SW. The reflected energy that is transferred after the discharge while extending the pulse width is charged in the capacitor C0 so that a reverse voltage is generated in the capacitor C0. Since the solid-state switch SW is off, the capacitor C
The current when the reverse voltage is generated at 0 is the inductance L
14 flows in the direction of the arrow in FIG. 14 to charge the main capacitor C0 in the forward direction. In this way, the reflected energy is regenerated in the main capacitor C0.

[0012]

In the circuit configuration including the regenerative circuit illustrated in FIGS. 13 and 14, the current is not consumed as shown in FIG. 12, but the reflected energy is regenerated. No large-scale cooling structure is required and the device does not become large. Further, since the reflected energy is not consumed as heat but is reused effectively, the current consumption of the entire laser becomes small. However, FIG. 13 and FIG.
The circuit configuration including the regenerative circuit illustrated in 4 has the following problems. As described above, the main capacitor C0
The electric charge of is transferred to the capacitor C1 via the step-up transformer TR1, and the turn ratio of the step-up transformer TR1 at that time is set so that the electric charge of the main capacitor C0 is completely transferred to the capacitor C1. On the other hand, in order to shorten the charging time to the peaking capacitor Cp as much as possible, to speed up the rising of the voltage applied to the main discharge electrodes E and to increase the discharge start voltage, the initial pulse input to the magnetic pulse compression circuit. Is preferably as short as possible. That is, it is preferable that the charge transfer rate from the main capacitor C0 to the capacitor C1 is as high as possible. The larger the number of turns on the primary side and the number of turns on the secondary side of the step-up transformer TR1, the slower the transition speed. Therefore, both turns are set to be minimum.

In the case of the turns ratio thus set, the reflected energy is reflected from the capacitor C1 to the main capacitor C0.
When the charge is transferred to the capacitor C1, all the charge in the capacitor C1 does not transfer to the main capacitor C0, and some residual charge is
Exists in 1. That is, in the case of FIG. 14, the step-up transformer T is configured so that the transitions in both the forward and reverse directions are performed 100%.
It is difficult to define the winding ratio of R1, and the residual charge is inevitably present in the capacitor C1.

In FIG. 13, the number of turns of the primary winding of the step-up transformer TR1 used is different between the time of pulse generation and the time of regeneration, but the secondary side is common. In the optimum winding ratio of the primary winding and the secondary winding used during regeneration, the primary winding corresponding to the secondary winding, which is the minimum required winding, is often not a natural number. Therefore, in order to make the number of turns on the primary side and the secondary side during regeneration a natural number, the number of turns on the secondary side increases. Then, the rate of charge transfer from the main capacitor C0 to the capacitor C1 at the time of pulse generation becomes slow.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to regenerate the reflected energy generated by the load impedance mismatch to the main capacitor without residual charge. It is an object of the present invention to provide a regenerative circuit of a high voltage pulse generator capable of improving regenerative efficiency.

[0016]

According to the present invention, in constructing a regenerative circuit, regenerative energy is not regenerated through a step-up transformer as in the conventional case, but a regenerative transformer is newly provided and the regenerative energy is regenerated. The reversal of energy is performed through the transformer. Further, a magnetic switch is provided in the regenerative circuit, and when the electric charge due to the reversal energy is charged in the capacitor C1, the magnetic switch is made conductive, and the electric charge charged in the capacitor C1 is transferred to the main capacitor C1.
The energy is transferred to 0 and the reversal energy is regenerated. That is, in the present invention, the above problems are solved as follows. (1) A charger, a main capacitor charged to a high voltage by this charger, a magnetic assist composed of a saturable reactor, and a switch means are connected in series to the primary side of the step-up transformer, In a regenerative circuit of a high-voltage pulse generator including a magnetic pulse compression circuit connected to the secondary side and a controller for controlling the switch means, in the regenerative circuit, the primary side winding has a secondary side of a step-up transformer. A regenerative transformer, which is connected in parallel with the winding and has a secondary winding and a series circuit of a diode connected to the main capacitor, regenerates reflected energy from the load side to the main capacitor. Then, the switch means is turned off by the controller before a regenerative current flowing to the main capacitor is generated during regenerative energy regeneration. (2) In the above (1), the magnetic switch is connected in series to the primary winding or the secondary winding of the regenerative transformer. (3) In the above (2), the magnetic assist formed of a saturable reactor connected in series to the primary side of the step-up transformer and the magnetic switch connected in series to the regenerative transformer are shared. (4) In the above (1), (2) and (3), the winding ratio of the regenerative transformer is determined so that residual charge does not exist on the secondary side of the step-up transformer when regenerating reflected energy. By configuring as in the above (1), the number of turns of the regenerative transformer and the number of turns ratio can be set independently of the step-up transformer. For this reason, some residual charge is generated by the capacitor C1.
It is possible to set the number of turns and the number of turns ratio of the regenerative transformer so that the number of turns does not exist. Further, as in the above (2), by providing a magnetic switch in the regenerative circuit, the charge charged in the capacitor C1 at the time of kickback is almost 100%.
%, It is possible to shift to the main capacitor C0.
Further, as in the above (3), by sharing the magnetic assist consisting of the saturable reactor connected in series with the primary side of the step-up transformer and the magnetic switch connected in series with the regenerative transformer in common, The number of switches can be reduced, the device can be downsized, and the cost can be reduced.

[0017]

1 shows a structural example of a high voltage pulse generator (discharge circuit) of a gas laser device having a regenerative circuit according to the first embodiment of the present invention, and FIG. 2 shows the main part of FIG. Voltages V0, V1, V2, Vp applied to the capacitor C0, the capacitors C1 and C2, and the peaking capacitor Cp
Voltage waveform and main capacitor C0 to capacitor C1
7 shows a current waveform when the charge is transferred to. The high voltage pulse generator shown in FIG. 1 is obtained by adding a regenerative circuit including a regenerative transformer Tr2, a diode D4, and a magnetic switch SR4 composed of a saturable reactor to the circuit shown in FIG. The primary side of the regenerative transformer Tr2 is connected in parallel with the capacitor C1, and the regenerative transformer T
A diode D4 and a magnetic switch SR are provided on the secondary side of R2.
4 are connected in series, and a series circuit including the secondary side, the diode D4, and the magnetic switch SR4 is connected in series to the main capacitor C0.

The circuit shown in FIG. 1 operates as follows. As shown in FIG. 2, when the time from the turning on of the solid switch SW to the saturation of the magnetic assist SR1 (magnetic assist time T in FIG. 2) elapses, the transfer of charges from the main capacitor C0 to the capacitor C1. Starts and current also flows (see the current waveform of the dashed line in the figure). Then, as described above, the voltage pulse shifts while being compressed by the magnetic pulse compression circuit to charge the peaking capacitor Cp. Capacitors C1, C2 at this time,
The voltage waveform of the peaking capacitor Cp is shown as V1, V in FIG.
2, Vp. Discharge is started during the charging of the peaking capacitor Cp (“discharge start” in the same figure), and the current moves in the opposite direction as reflected energy as described above. That is, as shown in FIG. 2, the voltage pulse goes backwards through the magnetic pulse compression circuit, so that the voltage pulse shifts while being expanded. The voltage waveforms of the capacitors C2, C1 and C0 at this time are V2kb, V1kb,
It is shown at V0 kb (broken line in FIG. 2). The voltage with which the capacitors C1 and C2 are charged by the reflected energy is referred to as a kickback voltage, and the phenomenon in which the reflected energy shifts in the opposite direction is referred to as a kickback. This kickback voltage is applied to the capacitor C during pulse compression.
The maximum voltage is 1/2 of the voltage charged in C1 and C2. Also,
In the operation of FIG. 2 described above, in order to transfer the charge from the main capacitor C0 to the capacitor C1, the solid state switch SW needs to be in the on state at least during the period A. Also,
During the regenerative operation, it is necessary to charge the main capacitor C0 via the regenerative circuit, during which the solid state switch SW is turned off.
Therefore, the solid state switch SW needs to be turned off for at least the period B.

Here, in the case where the regenerative circuit is not provided, the main capacitor C0 is charged so as to have a polarity opposite to that at the initial charging (when the solid state switch SW is on), as shown by the broken line in FIG. 2 (FIG. 2). V0kb (without regenerative circuit)]. on the other hand,
When the regenerative circuit is provided as shown in FIG. 1, it operates as follows. When the capacitor C1 is charged in the opposite direction by the reflected energy, the solid switch SW is in the off state, and the voltage (kickback voltage) charged in the capacitor C1 is generated on the secondary side of the regenerative transformer Tr2. Is applied to the series circuit of the diode D4, the magnetic switch SR4, and the main capacitor C0 provided on the secondary side of the regenerative transformer Tr4. Therefore, as shown in FIG.
The main capacitor C0 is initially charged (solid switch SW is o
It is charged so as to have the same polarity as that of (at the time of n). That is, the reflected energy is regenerated in the main capacitor C0 [see V0 kb (with regenerative circuit) in FIG. 2]. In the present embodiment, as described above, since the regenerative transformer Tr2 for regenerating the reflected energy is provided separately from the step-up transformer Tr1, the step-up transformer Tr1 does not intervene in the circuit operation during regeneration. Therefore, the number of turns of the regenerative transformer can be set to be large on both the primary side and the secondary side, and the turn ratio can be set freely, so that some residual charge may be generated by the capacitor C.
It is possible to precisely define the turn ratio so that the number of turns does not exist in 1. Further, naturally, it is not necessary to change the winding ratio and the winding number of the step-up transformer TR1, so that the winding ratio and the winding number of the step-up transformer TR1 are set so that the transfer speed of the charge from the main capacitor C0 to the capacitor C1 is as fast as possible. It becomes possible.

By providing the regenerative transformer Tr2 separately from the step-up transformer Tr1 as described above, the number of turns and the turn ratio of the regenerative transformer can be set independently of the step-up transformer Tr1, and the residual voltage of the capacitor C1 is shown in FIG. Although it can be reduced as compared with the circuit shown, the residual voltage can be further reduced by providing the magnetic switch SR4 in the regenerative circuit. The operation of the magnetic switch SR4 will be described below. After the discharge, the reflected energy moving while extending the pulse width charges the capacitor C1 to a reverse voltage as shown by V1kb in FIG. At this time, the solid-state switch SW is in the off state, and the voltage (kickback voltage) charged in the capacitor C1 is generated on the secondary side of the regenerative transformer Tr2, and this voltage is applied to the regenerative transformer Tr4 as described above. It is applied to the series circuit of the diode D4, the magnetic switch SR4, and the main capacitor C0 provided on the secondary side. The Vt product of the magnetic switch SR4 (integrated value of voltage (V) applied until the magnetic switch is saturated × time (t)) causes the kickback voltage to saturate the magnetic switch SR2 again,
The value is set so that the magnetic switch SR2 is saturated before the magnetic switch SR2 is saturated so that the capacitor C1 → the capacitor C2 does not move again in the forward direction. Also, the above V
The t product is set to a value that does not saturate immediately when a kickback voltage is applied, but saturates at least after the capacitor C1 is charged to the peak value by the kickback voltage. That is, V of the magnetic switch SR4
The t product is smaller than the Vt product of the magnetic switch SR2 converted to the secondary side of the regenerative transformer Tr2 and smaller than the Vt product of the regenerative transformer Tr2 until saturation.

Therefore, when the capacitor C1 is charged by the kickback voltage, the magnetic switch SR4 of the regenerative circuit is saturated and brought into a conductive state before the magnetic switch SR2 is saturated. As a result, the charge due to the kickback voltage charged in the capacitor C1 is discharged through the secondary side of the regenerative transformer Tr2, the diode D4, the magnetic switch SR4, and the circuit of the main capacitor C0, and the main capacitor C0 is charged. That is, the regenerative current is the regenerative transformer TR.
1 to flow in the direction of the arrow in FIG. 1, and reversely shifts to charge the main capacitor C0 in the forward direction. In this way, the reflected energy is regenerated in the main capacitor C0. that time,
Due to the inductance of the magnetic switch SR4, the current continues to flow even after the voltage of the main capacitor C0 and the voltage of the capacitor C1 become equal, and most of the charges charged in the capacitor C1 are transferred to the main capacitor C0. Further, due to the leakage current of the magnetic switch SR4 and the like, the transfer of the energy does not reach 100%, and a slight charge may remain in the capacitor C1.
By adjusting the turns ratio between the primary side and the secondary side of 2, the residual charge of the capacitor C1 can be made almost zero.
Note that when the solid switch SW is turned on to transfer a charge from the main capacitor C0 to the capacitor C1 in order to generate a discharge between the main discharge electrodes E, E, a voltage is applied to the diode D4 in the reverse direction. Does not flow to the regenerative transformer Tr1 side, but moves to the capacitor C1 via the step-up transformer TR1. Regenerative transformer Tr as described above
By connecting the diode D4 and the magnetic switch SR4 in series to the secondary winding of No. 2, the electric charge charged in the capacitor C1 can be transferred to the main capacitor C0 by almost 100%. In the above example, the magnetic switch SR4
Is provided on the secondary side of the regenerative transformer Tr2, the magnetic switch SR4 may be provided on the primary side of the regenerative transformer Tr2.

By the way, in a high voltage pulse power supply for a discharge excitation laser using a voltage doubler charging circuit, in order to regenerate the reflected energy to the power supply side, a regeneration transformer and a capacitor are connected in parallel to the primary side of the transformer. A pulse charging circuit has been proposed in which a connected regenerative circuit is provided, and the capacitor is charged with reflected energy to regenerate the power source (see Japanese Patent Laid-Open No. 5-327089). Therefore, regarding the effect of providing the magnetic switch, the regenerative circuit disclosed in Japanese Patent Laid-Open No. 5-327089 is applied to the voltage transfer type magnetic pulse compression circuit shown in FIG. Description will be made in comparison with the illustrated regenerative circuit. Figure 3
FIG. 3 is a diagram showing a circuit configuration in the case where the regenerative circuit described in Japanese Patent Laid-Open No. 5-327089 is applied to a voltage transfer type magnetic compression circuit. In the regenerative circuit shown in FIG. 3, the magnetic switch SR4 is not provided, and the regenerative transformer T
A capacitor CR is connected in parallel with the primary winding of r2. Therefore, when the capacitor C1 is charged by the kickback voltage, the capacitor CR is charged with a voltage equal to the charging voltage of the capacitor C1. Then, the electric charge charged in the capacitor CR is transferred to the main capacitor C0, and the electric charge remains in the capacitor C1. This residual charge vibrates in the magnetic compression circuit as described above and adversely affects the discharge. Assuming that the capacitors CR and C1 have the same capacitance, the charge charged in the capacitor CR is 1 / the amount of charge generated by kickback.
Therefore, 1/2 of the electric charge is not regenerated and remains in the capacitor C1 as a residual electric charge.

On the other hand, in the regenerative circuit shown in FIG. 1, the capacitor CR is not connected in parallel with the capacitor C1, and a magnetic switch SR4 that is reversely excited in the regenerative current direction is provided in the regenerative circuit. Has been. Therefore, the inversion charges generated by the kickback are transferred from the capacitor C2 to the capacitor C1 and then transferred from the capacitor C1 to the main capacitor C0 by almost 100% via the regenerative transformer Tr2. Therefore, the capacitor C
The residual charge amount of 1 can be greatly reduced as compared with the regenerative circuit of FIG.

In the LC inverting type circuit as described in the above-mentioned Japanese Patent Laid-Open No. 5-327089, the residual charge remains in the circuit without vibrating, but in the voltage transfer type magnetic pulse compression circuit, When the regenerative circuit described in the publication is applied, the electric charge remaining as described above vibrates in the magnetic compression circuit. Further, in FIG. 3 above,
The case where the capacitor CR is provided in parallel on the primary side of the regenerative transformer Tr2 has been described. However, even when the capacitor CR is not provided, the main capacitor C0 is connected in parallel to the capacitor C1 via the regenerative transformer Tr1. Therefore, the residual charge remains in the capacitor C1, and the residual charge vibrates in the magnetic pulse compression circuit.

FIGS. 4 and 5 show time charts during regeneration of the regenerative circuit of this embodiment shown in FIG. 1 and the regenerative circuit shown in FIG. 4 and 5, V0, V1, V2
Vcp is the main capacitor C0, the capacitors C1, and
C2 represents the voltage of the peaking capacitor Cp, and Vcr in FIG. 5 represents the voltage charged in the capacitor CR in FIG. In the regenerative circuit of the present embodiment, as described below, most of the electric charge due to kickback is the main capacitor C.
It is regenerated to 0, and the vibration due to the above-mentioned residual charge does not occur. That is, as shown in FIG. 4, at time t1, the transfer of charges from the main capacitor C0 to the capacitor C1 starts, and the voltage pulse is pulse-compressed by the magnetic pulse compression circuit to the capacitor C2 and the peaking capacitor Cp as described above. After shifting (t2 and t3 in FIG. 4), the peaking capacitor Cp is charged. Discharge starts during the charging of the peaking capacitor Cp (t4 in FIG. 4), and as described above, the current shifts in the opposite direction as reflected energy. That is, the electric charges charged in the peaking capacitor Cp in the opposite direction are transferred to the capacitors C2 and C1 (t5 and t6 in FIG. 4). When the capacitor C1 is charged by the kickback, the magnetic switch SR4 of the regenerative circuit described above is turned on, and the electric charge charged in the capacitor C1 is transferred to the main capacitor C0 via the regenerative transformer Tr1. As shown in, the main capacitor C
0 is charged, and at time t7, the electric charge of the capacitor C1 is transferred to the main capacitor C0 by almost 100%.

On the other hand, in the regenerative circuit shown in FIG.
Since the residual electric charge remains in the capacitor C1, as described below, the residual electric charge in the capacitor C1 causes vibration, which adversely affects the discharge. That is, as shown in FIG. 5, at time t1, the transfer of charges from the main capacitor C0 to the capacitor C1 starts, and the voltage pulse is compressed by the magnetic pulse compression circuit to the capacitor C2 and the peaking capacitor Cp as described above. After shifting (t2 and t3 in FIG. 5), the peaking capacitor Cp is charged. Discharge starts during the charging of the peaking capacitor Cp (t4 in FIG. 5), and as described above, the current shifts in the opposite direction as reflected energy. That is, the electric charges charged in the peaking capacitor Cp in the opposite direction are transferred to the capacitors C2 and C1 (t5 and t6 in FIG. 5).
Due to the kickback, the charge of the capacitor C2 is transferred to the capacitors C1 and CR at the same time.
Since electric charge remains in No. 1, the forward transfer of the voltage pulse starts again due to this residual electric charge (after t6 and t7 in FIG. 5), and as shown in FIG. 5, due to this forward transfer and kickback. Vibration occurs and the voltage is applied to the load multiple times. On the other hand, the electric charge charged in the capacitor CR is transferred to the main capacitor C0 via the regenerative transformer Tr2. Although the magnetic assist SR4 is provided on the secondary side of the regenerative transformer TR2 in FIG.
May be provided on the primary side of the regenerative transformer TR2.

In FIG. 1, the magnetic switch SR is provided in the regeneration circuit.
4 has been described, the magnetic switch SR4 may be used also as the magnetic switch SR1 connected to the main capacitor C0. FIG. 6 shows the magnetic assist SR1.
2 shows a circuit configuration of a second embodiment of the present invention in which is operated as the magnetic switch. In this embodiment, as shown in FIG. 6, the cathode side of the diode D4 connected to the secondary side of the regenerative transformer Tr2 is connected to the connection point between the magnetic assist SR1 and the primary winding of the step-up transformer Tr1.
With the above configuration, the main capacitor C0 during regeneration
Charging current flows as indicated by the arrow in FIG. That is, since the charging current flows through the magnetic assist SR1, the Vt product of the magnetic assist SR1 is set to a value similar to that of the magnetic switch SR4, so that the same function as that of the magnetic switch SR4 can be achieved.
Can fulfill. In addition, V of the magnetic assist SR1
The t product cannot be freely set to a value because it is defined to some extent by the magnetic compression operation.
The magnetic switch can be operated by adjusting the winding ratio of 2 or the like. 1 and 6, the diode D4 is provided on the secondary side of the regenerative transformer TR2.
It may be provided on both sides of the primary side and the secondary side. With such a configuration, the volume of the core of the regenerative transformer TR2 can be halved.

By the way, as described above, in order to perform the regenerative operation, the solid state switch SW must be in the off state by the time point (C) in FIG. The solid state switch SW must be in the on state while the charge is transferred from the capacitor C0 to the capacitor C1. That is, in FIG. 2, the solid state switch SW must be in the on state from the time point (time point (A)) when the solid state switch SW is turned on to the time point (B).
To summarize the above, the solid-state switch SW must be in the on state during the period A in FIG. 2 and must be in the off state at any point in the period B.

By the way, in the gas laser device used as the light source for exposure, it is required that the laser output energy is constant, and the output energy constant control is performed. The exposure gas laser device 1 including the discharge circuit 1a that performs the above control includes a controller 2, a monitor module 3, and a beam splitter 4 as shown in FIG. 7, for example.
Have. A part of the laser light emitted from the exposure gas laser device 1 is extracted by the beam splitter 4 and guided to the monitor module 3 for measuring the laser output energy. The monitor module 3 measures the laser output energy and sends the measurement result to the controller 2. The controller 2 adjusts the voltage of the high voltage power supply HV of the discharge circuit (high voltage pulse generator) shown in FIG. 7 so that the laser output energy becomes constant. That is, the voltage of the high-voltage power supply HV, that is, the voltage V0 of the main capacitor C0 changes for each laser pulse, and the laser output energy becomes constant.

The magnetic assist time of the magnetic assist SR1 is constant because the Vt product of the magnetic switch, which is a saturable reactor, is constant when V0 fluctuates as described above.
The magnetic assist time T also changes so that the product becomes constant.
Therefore, the length of the period A in FIG. 2 also changes. As described above, the solid switch SW is on-off.
The control needs to be performed corresponding to the periods A and B, but at this time, it is necessary to consider the fluctuation of the period A caused by the fluctuation of the magnetic assist time T described above. Further, the period B is also a function of the voltage as in the case of A, so it is necessary to consider it.

Next, the structure of the control device capable of controlling the on-off of the solid state switch SW according to the periods A and B will be described. Figure 8 shows the solid state switch S
The 1st example of composition of the control device for performing on-off control of W is shown. The controller in FIG. 8 is the same as the controller 2 in FIG. 7, and receives the data of the measurement result of the laser output energy transmitted from the monitor module 3. Based on the received laser output energy data, the controller 2 calculates and determines the charging voltage for the main capacitor C0 for the next discharge by the charging voltage value calculator 2a. Then, the charging voltage value adjustment command is transmitted to the high voltage power source HV so that the charging voltage to the main capacitor C0 becomes the determined voltage value, and the high voltage power source HV is controlled. At the same time, the controller 2 sends the charging voltage value data of the main capacitor C0 determined by the charging voltage value calculation unit 2a to the switch on-off timing control unit 2b. The switch on-off timing control unit 2b calculates the magnetic assist time T based on the received charging voltage value data and the Vt product of the magnetic assist SR1 stored in advance in the switch on-off timing control unit 2b, and the period A
Find the length of. That is, the current pulse width Ti in FIG. 2 is determined to be substantially constant from the value of the circuit constant, and is stored in the switch on-off timing control unit 2b in advance. The switch on-off timing control unit 2b determines the length of the period A from the sum of the calculated magnetic assist time T and the current pulse width Ti stored in advance. Also,
The period B is determined by the charging voltage value data and the circuit constant of the magnetic pulse compression circuit. Therefore, for example, the relationship between the voltage value and the period B is obtained in advance and stored in a storage circuit or the like. Then, the period B corresponding to the charging voltage value data is read from the storage device.

The on-off timing control section 2b controls the on-off frequency of the solid-state switch SW based on the set repetition frequency, but on the basis of the periods A and B obtained as described above, the solid-state switch is controlled. The solid state switch SW is set to be a starting point from the time point when the on signal is transmitted to the SW (time point (A) in FIG. 2) and before the end of the time period B (between time point (B) and time point (C) in FIG. 2). To of
The f signal is transmitted. It should be noted that the off signal is transmitted later than the time point (B) in FIG. 2 in consideration of the deviation between the time point when the on signal is transmitted to the solid state switch SW and the time point when the solid state switch SW is actually turned on and the variation (jitter) of the deviation. It is desirable to do. In addition, the off signal may be transmitted before the time point (C) in consideration of the deviation between the time point when the off signal is transmitted to the solid state switch SW and the time point when the solid state switch SW is actually turned off, and the fluctuation (jitter) of the deviation. desirable.
While the regenerative operation is performed by the above configuration and control,
The solid-state switch SW can be surely turned off.

FIG. 9 shows a second configuration example of the control device for performing on-off control of the solid-state switch SW. The configuration example of the control device shown in FIG. 9 is a modification of the first configuration example shown in FIG. 8, and the difference is that in the first configuration example, the main capacitor C0 from the charging voltage value calculation unit 1a of the controller 2 is different.
While the magnetic assist time T is calculated by using the charging voltage value data of the above, in the second configuration example, the voltage value of the main capacitor C0 is directly detected by the voltage detector Vs, and this detection data is obtained. The magnetic assist time T is calculated using this.
That is, the voltage detector Vs measures the measured main capacitor C.
The charging voltage value data of 0 is transmitted to the switch on-off timing control unit 2b. As described above, the switch on-off timing control unit 2b determines the length of the period A based on the received charging voltage value data and the Vt product of the magnetic assist SR1 stored in the switch on-off timing control unit 2b in advance. In addition to the above, the period B is calculated as described above.

The on-off timing control section 2b determines the on-off of the solid state switch SW based on the repetition frequency.
Although the frequency of f is controlled, the period A calculated as described above is used.
Based on the period B and the period B, the time point at which the on signal is transmitted to the solid state switch SW (time point (A) in FIG. 2) is used as the starting point.
After the lapse of the period A and before the end of the period B (between the time point (B) and the time point (C) in FIG. 2), the solid state switch SW is turned off.
The f signal is transmitted. As in the case of the first configuration example,
The off signal should be transmitted later than the time point (B) in FIG. 2 in consideration of the deviation between the time point when the on signal is transmitted to the solid state switch SW and the time point when the solid state switch SW is actually turned on or the fluctuation (jitter) of the deviation. Is desirable. In addition, the off signal may be transmitted before the time point (C) in consideration of the deviation between the time point when the off signal is transmitted to the solid state switch SW and the time point when the solid state switch SW is actually turned off, and the fluctuation (jitter) of the deviation. desirable. By performing control using the above control device, the solid state switch SW can be surely turned off while the regenerative operation is performed.

[0035]

As described above, the following effects can be obtained in the present invention. (1) Since the inversion charge (reflected energy) due to the difference in the impedance of the load is not consumed as heat but is regenerated to the main capacitor C0, unlike the case where it is consumed as heat, a large-scale cooling structure is not required and the device is The size of the laser does not increase, and the current consumption of the entire laser decreases. (2) Further, in performing the regenerative operation, in the present invention, the regenerative transformer T is individually provided for regenerating the reflected energy.
Since R2 is provided, step-up transformer T can be used for circuit operation during regeneration.
The number of turns and the number of turns ratio of the regenerative transformer can be set independently of the step-up transformer without R1. For this reason,
By making the number of turns of the regenerative transformer large on both the primary side and the secondary side, it is possible to precisely specify the turns ratio so that some residual charges do not exist in the capacitor C1. Also,
Of course, it is not necessary to change the winding ratio and the winding number of the step-up transformer TR1, so that the winding ratio and the winding number of the step-up transformer TR1 can be set so that the transfer speed of the charges from the main capacitor C0 to the capacitor C1 is as fast as possible. It will be possible. (3) By providing a magnetic switch in the regenerative circuit,
Almost 100% of the electric charge charged in the capacitor C1 during kickback can be transferred to the main capacitor C0. Therefore, it is possible to suppress the generation of residual charge in the capacitor C1, avoid adverse effects on the main discharge electrode, and improve the regeneration efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a high voltage pulse generator having a regenerative circuit according to a first embodiment of the present invention.

FIG. 2 is a time chart explaining the operation of the regenerative circuit shown in FIG.

FIG. 3 is a diagram showing a configuration example of a regenerative circuit having a regenerative transformer for comparing the operation with the regenerative circuit of the present invention.

FIG. 4 is a diagram showing a time chart during regeneration of the regenerative circuit of the first embodiment.

5 is a diagram showing a time chart during regeneration of the regenerative circuit shown in FIG.

FIG. 6 is a diagram showing a configuration of a regenerative circuit according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a configuration example of a control system of an exposure gas laser device.

FIG. 8 is a diagram showing a configuration example (1) of a control device for controlling a solid-state switch of a high-voltage pulse generator.

FIG. 9 is a diagram showing a configuration example (2) of a control device for controlling a solid state switch of a high voltage pulse generator.

FIG. 10 is a diagram showing a configuration example of a high voltage pulse generator.

11 is a diagram showing waveforms of a voltage applied to the capacitor C2 and a voltage applied to the peaking capacitor Cp in FIG.

FIG. 12 is a diagram showing a configuration example of a discharge circuit of a gas laser device having a circuit for processing charges generated by a reverse voltage with a resistor.

FIG. 13 is a diagram showing a configuration example (1) of a high voltage generator having a regenerative circuit configuration for energy regeneration.

FIG. 14 is a diagram showing a configuration example (2) of a high voltage generator having a regenerative circuit configuration for energy regeneration.

[Explanation of symbols]

SR1 magnetic assist SR2, SR3 magnetic switch SR4 magnetic switch SW solid state switch C0 main capacitor Tr1 step-up transformer C1, C2 capacitors Cp peaking capacitor E Main discharge electrode Tr2 regenerative transformer D4 diode Vs voltage detector 1 Gas laser device for exposure 1a discharge circuit 2 controller 2a Charge voltage value calculator 2b switch on-off timing controller 3 Monitor module 4 beam splitter

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5F071 AA06 GG03                 5H790 BA02 BB15 CC01 CC06 DD06                       EA01 EA02 EA03 EA07 EA11

Claims (4)

[Claims] 1. A charger, a main capacitor charged to a high voltage by the charger, a magnetic assist consisting of a saturable reactor, and a switch means are connected in series to the primary side of a step-up transformer. A regenerative circuit in a high-voltage pulse generator comprising a magnetic pulse compression circuit connected to the secondary side of the transformer, and a controller for controlling the switch means, wherein the regenerative circuit has a primary winding of a step-up transformer. Energy reflected from the load side, which is connected in parallel with the first-stage capacitor of the magnetic pulse compression circuit connected to the secondary winding of the, and the series circuit of the secondary winding and the diode is connected to the main capacitor. Is equipped with a regenerative transformer that regenerates the main capacitor, and the controller described above regenerates the regenerated energy before the regenerative current flowing to the main capacitor occurs. Regeneration circuit in the high-voltage pulse generating device and having a function of a switch means in the off state. 2. The primary winding or 2 of the regenerative transformer
The regenerative circuit in the high voltage pulse generator according to claim 1, wherein a magnetic switch is connected in series to the secondary winding. 3. A magnetic assist comprising a saturable reactor connected in series to the primary side of the step-up transformer and a magnetic switch connected in series to the regenerative transformer are used in common. Circuit in the high-voltage pulse generator of. 4. The winding ratio of the regenerative transformer is set so that residual charge is minimized on the secondary side of the step-up transformer during regeneration of reflected energy. A regenerative circuit in the high-voltage pulse generator according to claim 3.