JP4702889B2 - Gas laser device power supply circuit - Google Patents

Description

  The present invention performs a magnetic pulse compression operation of energy by a multi-stage capacitor and a magnetic switch to generate a main discharge between main discharge electrodes, and regenerates energy not consumed in the main discharge as the next main discharge energy, The present invention relates to a power supply circuit of a gas laser apparatus that performs the next magnetic pulse compression operation after resetting the operating point of each magnetic switch.

  With the miniaturization and high integration of semiconductor integrated circuits, improvement in resolving power is demanded in the projection exposure apparatus for production. For this reason, the wavelength of the exposure light emitted from the exposure light source is being shortened, and a KrF excimer laser device having a wavelength of 248 nm from a conventional mercury lamp is used as a light source for semiconductor exposure. Further, as a next-generation light source for semiconductor exposure, gas laser devices that emit ultraviolet rays, such as an ArF excimer laser device having a wavelength of 193 nm and a fluorine (F2) laser device having a wavelength of 157 nm, are promising. In the KrF excimer laser device, a mixed gas composed of a rare gas such as fluorine (F2) gas, krypton (Kr) gas and neon (Ne) as a buffer gas, and in the ArF excimer laser device, fluorine (F2) gas, argon (Ar) gas and a mixed gas composed of a rare gas such as neon (Ne) as a buffer gas, and in a fluorine (F2) laser apparatus, a fluorine (F2) gas and a rare gas such as helium (He) as a buffer gas A laser gas as a laser medium is excited by generating a discharge inside a laser chamber in which a laser gas as a mixed gas is sealed at several hundred KPa.

  Inside the laser chamber, a pair of main discharge electrodes for exciting the laser gas are disposed facing each other at a predetermined distance in a 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 breaks down and main discharge starts. The laser medium is excited by this main discharge. Such an exposure gas laser apparatus performs pulse oscillation by repeating main discharge, and the emitted laser light becomes pulse light. At present, the repetition frequency of the laser pulse of the laser apparatus used for exposure is about 4 KHz, but in recent years, a repetition frequency of 6 KHz or more has been demanded in order to increase the throughput and decrease the variation in exposure amount.

  FIG. 4 shows an example of a high voltage pulse generator (hereinafter sometimes referred to as a power supply circuit) for generating a discharge in the laser chamber and exciting the laser gas in the above-described exposure gas laser apparatus.

  The power supply circuit of FIG. 4 has a main capacitor C0 connected in parallel to the high voltage power supply HV, a boosting primary winding TC11, and a boosting secondary winding TC12, which is the boosting primary winding TC11. The primary capacitor C0 has a step-up transformer TC1 connected in parallel via a magnetic assist SR1 and a solid switch SW, a regenerative primary winding TC21 and a regenerative secondary winding TC22. TC21 has a regenerative transformer TC2 connected in parallel to the main capacitor C0 via a diode D1, a plurality of transfer capacitors C1, C2 and magnetic switches SR2, SR3, and the first stage transfer capacitor C1 is used for the boosting. A transfer capacitor C2 in the n-th stage (n = 2 to k (k is 2 or more)) is connected in parallel to the secondary winding TC12 and in parallel to the regenerative secondary winding TC22 via a diode D2. Is the n-1 stage magnetic field A magnetic pulse compression circuit connected in parallel to the (n-1) th stage transfer capacitor C1 through the switch SR2, and a parallel connection to the kth stage transfer capacitor C2 through the kth stage magnetic switch SR3. And a pair of main discharge electrodes E and E connected in parallel to the peaking capacitor Cp, and a magnetic assist that is wound around the core of the magnetic assist SR1 and resets the operating point of the core in response to energization. A reset winding LR1 for winding, a reset winding LR2 for magnetic switch that is wound around the core of the n-th magnetic switch SR2 and resets the operating point of the core in response to energization, and a core for the boosting transformer TC1 A step-up transformer reset winding TC1R that is wound and resets the operating point of the core in response to energization, and is wound around the core of the regenerative transformer TC2 and applied in response to energization. A regenerative transformer reset winding TC2R for resetting the operating point of the core.

  The magnetic assist reset winding LR1, the magnetic switch reset winding LR2, the boosting transformer reset winding TC1R, and the regeneration transformer reset winding TC2R are connected in series and connected to the power supply CS.

  The power supply circuit of FIG. 4 has a two-stage magnetic pulse compression circuit using three magnetic switches SR1, SR2, SR3 made of a saturable reactor. The magnetic switch SR1 is a magnetic switch for reducing a switching loss generated in a solid switch SW which is a semiconductor switching element such as an IGBT, and is also called a magnetic assist. The magnetic switch will be described in detail later with reference to FIGS.

The operation of the power supply circuit shown in FIG. 4 will be described with reference to FIG.
First, the solid switch SW is turned off, and the main capacitor C0 is charged by the high voltage power supply HV adjusted to the voltage value Vin. The charging voltage of the main capacitor at this time is assumed to be positive. When the solid switch SW is switched from OFF to ON, the charging voltage Vc1 of the main capacitor C0 is applied to the magnetic assist SR1. When the time integral value of the charging voltage Vc0 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 inductance of the magnetic assist SR1 is reduced. This timing is indicated by time t1 in FIG. Then, a current flows through the loop of the main capacitor C0, the magnetic assist SR1, the primary winding TC11 of the step-up transformer TC1, and the solid switch SW. At the same time, a current also flows through the loop of the secondary winding TC12 and the first-stage transfer capacitor C1 of the step-up transformer TC1, and the charge stored in the main capacitor C0 is transferred to the first-stage transfer capacitor C1. The first-stage transfer capacitor C1 is charged to the negative side.

  When the time integration value of the charging voltage Vc1 of the first-stage transfer capacitor C1 reaches a limit value determined by the characteristics of the magnetic switch SR2, the magnetic switch SR2 is saturated and the inductance of the magnetic switch SR2 decreases. This timing is indicated by time t2 in FIG. Then, a current flows through the loop of the first-stage transfer capacitor C1, the second-stage transfer capacitor C2, and the magnetic switch SR2, and the charge stored in the first-stage transfer capacitor C1 is transferred to the second-stage transfer capacitor C2. The second transfer capacitor C2 is charged to the negative side.

  Further, when the time integration value of the charging voltage Vc2 of the second-stage transfer capacitor C2 reaches a limit value determined by the characteristics of the magnetic switch SR3, the magnetic switch SR3 is saturated and the inductance of the magnetic switch SR3 is rapidly reduced. This timing is indicated by time t3 in FIG. Then, a current flows through the loop of the second-stage transfer capacitor C2, peaking capacitor Cp, and magnetic switch SR3, and the charge stored in the second-stage transfer capacitor C2 is transferred to the peaking capacitor Cp. Charged to the negative side.

  When the voltage Vcp of the peaking capacitor Cp reaches a certain value (breakdown voltage) Vb, the laser gas between the main discharge electrodes E and E breaks down and main discharge is started. This main discharge excites the laser medium to generate light.

  In order to generate a large discharge at the main discharge electrodes E, E, charge transfer from the first-stage transfer capacitor C1 to the second-stage transfer capacitor C2, and from the second-stage transfer capacitor C2 to the peaking capacitor Cp. Each element of the magnetic pulse compression circuit (C1, SR1, C2, SR2) is designed so that a so-called magnetic pulse compression operation for sequentially reducing the pulse width of the current pulse is performed during the charge transfer.

  By the way, in the conventional power supply circuit, after the main discharge, the charge travels in the reverse direction between the peaking capacitor Cp and the main capacitor C0 and further proceeds in the forward direction, thereby adversely affecting the main discharge. Therefore, as shown in FIG. 4, the present inventors accumulate the charge transferred from the peaking capacitor Cp to the main capacitor C0 after the main discharge in the main capacitor C0 so that it can be regenerated as part of the next charging energy. A regenerative circuit (TC2, D1, D2) was developed. This regenerative circuit is disclosed in Patent Document 1 below.

An energy regeneration operation using the regeneration circuit will be described.
After the main discharge, a reverse voltage is applied to the peaking capacitor Cp due to residual charges of the main discharge. That is, the peaking capacitor Cp is charged to the positive side. This timing is indicated by time t4. Then, charges are sequentially transferred from the peaking capacitor Cp to the second-stage transfer capacitor C2 and from the second-stage transfer capacitor C2 to the first-stage transfer capacitor C1. Similarly to the peaking capacitor Cp, the transfer capacitors C2 and C1 are applied with a voltage having a polarity opposite to that of the charging voltage during the magnetic pulse compression operation. That is, the transfer capacitors C2 and C1 are also charged to the positive side. The respective timings are indicated by times t5 and t6 in FIG.

  The solid switch SW is turned off during the regenerative operation. Therefore, charge transfer from the first-stage transfer capacitor C1 to the main capacitor C0 is performed via the regeneration transformer TC2. The main capacitor C0 is charged to the same polarity as the voltage charged by the high voltage power supply HV, that is, to the positive side. At this time, the solid switch SW is turned off, and the diodes D1 and D2 of the regenerative circuit are connected in reverse polarity, so that the charge is stored in the main capacitor C0 until the solid switch SW is turned on next time. The

Here, the operation of the magnetic switch will be described in more detail.
FIG. 6 shows a general configuration of a saturable reactor constituting the magnetic switch, and FIG. 7 shows a magnetization curve of the core of the saturable reactor constituting the magnetic switch.
As shown in FIG. 6, a main winding SR and a reset winding LR are wound around the core CR. The reset winding LR is connected to the reset circuit RC. First, when a DC current flows through the reset winding LR when the operating point of the core CR is at the “0” point in FIG. 7, the operating point of the core CR moves to the point (5). When an exciting current flows through the main winding SR, the magnetic field strength H increases, and the operating point of the core CR moves from the point (5) through the point (4) toward the point (1).

  When the operating point of the core CR reaches the point (1), the magnetic flux density in the core CR 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 rapidly decreases, and the main winding SR becomes conductive. When the saturable reactor is saturated, the operating point of the core CR is at a position where the magnetic field force H is much larger than that of (1), but from the point (1) along with the decrease in the current flowing through the main winding SR. (2) Move toward the point. At this time, since the inductance of the saturable reactor increases rapidly, the current flowing through the main winding SR decreases rapidly. The operating point of the core CR when the current of the main winding SR becomes 0 stops at the point (2), and the magnetic flux remains in the core CR (residual magnetic flux).

  When the excitation current flows through the main winding SR again with the operating point of the core CR at the point (2), the operating point of the core CR moves from the point (2) to the point (1). The amount of change in the magnetic flux density is smaller than moving from point (5) through point (4) toward point (1). For this reason, the inductance of the saturable reactor at the time of non-saturation is not sufficiently increased, and the magnetic pulse compression operation in the magnetic pulse compression circuit can hardly be performed. In order to perform the magnetic pulse compression operation, it is necessary to perform a magnetic reset so that the operating point of the core CR is returned from the point (2) in FIG. 6 to the point (5) via the point (3). Therefore, after the direct current (reset current) in the direction opposite to that of the main winding SR is passed through the reset winding LR and the current of the main winding SR becomes 0, the operating point of the core CR becomes the point (5). Returned.

The power supply circuit shown in FIG. 4 includes a reset current circuit in which reset windings LR1 to LR3 corresponding to the magnetic switches SR1 to SR3 and reset windings TC1R and TC2R corresponding to the transformers TC1 and TC2 are connected in series. ing. The reset winding and the reset current circuit are disclosed in Patent Documents 2 and 3 below, for example.
JP 2003-250279 A JP 2003-283017 A JP 2004-71613 A

  Since the current flows through the reset current circuit even after the main capacitor C0 is charged by the energy regeneration operation, the voltages Vc1, Vc2, and Vcp of the transfer capacitors C1, C2 and the peaking capacitor Cp change. At the timing of completion of the energy regeneration operation, the voltage Vc1 of the first-stage transfer capacitor C1, the voltage Vc2 of the second-stage transfer capacitor C2, and the voltage Vcp of the peaking capacitor Cp are substantially zero. The voltage Vcp and the voltage Vc2 decrease on the negative side as time elapses, coincide with each other at the timing when the core of the magnetic switch SR3 is reset, and increase on the negative side. On the other hand, the voltage Vc1 rises on the positive side with time and then falls.

  At the timing when the core of the magnetic switch SR2 is reset, the voltages Vc1, Vc2, and Vcp coincide and rise together, and at the timing when the core of the boosting transformer TC1 is reset, the voltages Vc1, Vc2, and Vcp fall. It converges to zero. If the repetition frequency of the laser pulse is about 4 KHz or less as in the prior art, the pulse interval is about 250 μs or more, and the voltages Vc1, Vc2, and Vcp are 0 after the main discharge occurs until the next magnetic pulse compression operation. Converge to.

  However, if the repetition frequency of the laser pulse is about 6 KHz or more, the pulse interval is about 166 μs or less, and the next magnetic pulse compression operation is started before the voltages Vc1, Vc2, and Vcp converge to zero. This is because the peak values of the voltages Vc1, Vc2, and Vcp on the positive side are high and it takes time to converge to zero. If charging is started by the magnetic pulse compression operation when a voltage is generated in the peaking capacitor Cp, the main discharge is adversely affected.

  The present invention has been made in view of such a situation. By reducing the peak value of the voltage Vcp charged in the peaking capacitor Cp as a result of the reset current before the magnetic pulse compression operation as much as possible, a laser with a high repetition frequency is obtained. Even if it is an apparatus, it aims at obtaining favorable discharge.

In order to achieve the above object, the first invention provides:
A main capacitor (C0) connected in parallel to a high voltage power supply (HV);
It has a primary winding for boosting (TC11) and a secondary winding for boosting (TC12), and the primary winding for boosting (TC11) has a magnetic assist (SR1) and a solid switch (SW) on the main capacitor (C0). ) Via a step-up transformer (TC1) connected in parallel via
It has a primary winding for regeneration (TC21) and a secondary winding for regeneration (TC22), and the primary winding for regeneration (TC21) is connected in parallel to the main capacitor (C0) via a diode (D1). Regenerative transformer (TC2),
A plurality of transfer capacitors (C1, C2) and magnetic switches (SR2, SR3), and the first-stage transfer capacitor (C1) is in parallel with the secondary winding for boosting (TC12) and the secondary winding for regeneration. N (n = 2 to k (k is 2 or more)) stage transfer capacitor (C2) connected in parallel to line (TC22) via diode (D2) and n−1 stage magnetic switch A magnetic pulse compression circuit connected in parallel to the transfer capacitor (C1) of the (n-1) th stage via (SR2);
A peaking capacitor (Cp) connected in parallel to the k-th transfer capacitor (C2) via the k-th magnetic switch (SR3) of the magnetic pulse compression circuit;
A pair of main discharge electrodes (E, E) connected in parallel to the peaking capacitor (Cp);
A magnetic assist reset winding (LR1) wound around the core of the magnetic assist (SR1) and resetting the operating point of the core in response to energization;
A magnetic switch reset winding (LR2) wound around the core of the n-th magnetic switch (SR2) and resetting the operating point of the core in response to energization;
A step-up transformer reset winding (TC1R) wound around the core of the step-up transformer (TC1) and resetting the operating point of the core in response to energization;
A regenerative transformer reset winding (TC2R) wound around the core of the regenerative transformer (TC2) and resetting the operating point of the core in response to energization;
With
The charges accumulated in the main capacitor (C0) by the high-voltage power supply (HV) are sequentially compressed through the step-up transformer (TC1) to the subsequent transfer capacitors (C1, C2) while the current pulse width is compressed. Then, it is further transferred to the peaking capacitor (Cp) to generate a main discharge between the main discharge electrodes (E, E). After the main discharge, electric charges are transferred from the peaking capacitor (Cp) to the transfer capacitors (C2) in the preceding stage. , C1), and further transferred to the main capacitor (C0) through the regenerative transformer (TC2) and the diode (D1) and regenerated by the main capacitor (C0). In
The voltage of the peaking capacitor (Cp) generated due to the current flowing through each of the reset windings (LR1, LR2, TC1R, TC2R) at a predetermined time after the main discharge corresponds to the predetermined time after the main discharge. It is characterized by being suppressed below the set upper limit value.

Further, the second invention is the first invention,
The turn ratio n _TC12 / n _{TC11 of the} boosting primary winding (TC11) and the boosting secondary winding (TC12) of the boosting transformer (TC1) and the primary winding for regeneration of the regenerative transformer (TC2) The turn ratio n _TC22 / n _{TC21 of the} wire (TC21) and the regenerative secondary winding (TC22) and the capacitance ratio Cc0 / Cc1 of the main capacitor (C0) and the first stage transfer capacitor (C1) The voltage Vc1 of the first stage transfer capacitor (C1) rises from negative after the charge is transferred in advance and transferred from the peaking capacitor (Cp) to the main capacitor (C0). It is characterized by this.

Further, the third invention is the first invention,
The number of turns n _TC12 of the step-up secondary winding (TC12) of the step-up transformer (TC1) and the number of turns n _{TC1R of the} step-up transformer reset winding (TC1R), and the regenerative secondary of the regenerative transformer (TC2) and the number of turns n _TC2r turns n _TC22 and the regeneration transformer reset winding windings (TC22) (TC2R), the capacity of each transfer capacitor (C1, C2) and the peaking capacitor (Cp) Cc1, ... Cck, Ccp Are adjusted in advance, and the voltage rising speed of the peaking capacitor (Cp) is set to be equal to or lower than a predetermined speed.

Moreover, 4th invention is 2nd invention,
(N _TC12 / n _TC11 )> √ (Cc0 / Cc1)
(N _TC22 / n _TC21 ) <√ (Cc0 / Cc1)
It is characterized by the following relational expression.

The fifth invention is the third invention, wherein
When the reset current flowing in the boosting transformer reset winding (TC1R) is ITC1R and the reset current flowing in the regeneration transformer reset winding (TC2R) is ITC2R,
_{{ITC1R × (n TC12 / n} TC1R) -ITC2R × (n TC22 / n TC2R)}
/(Cc1+...+Cck+Ccp) <K
_{(However, {ITC1R × (n TC12 /} n TC1R) -TC2R × (n TC22 / n TC2R)}> is 0, K is a constant)
It is characterized by the following relational expression.

  The first invention will be described with reference to FIGS.

  In the first invention, each element is connected as shown in FIG. The charges accumulated in the main capacitor C0 by the high voltage power supply HV are sequentially transferred to the peaking capacitor Cp via the boosting transformer TC1 and the transfer capacitors C1 and C2. When the voltage Vcp of the peaking capacitor Cp reaches the breakdown voltage, main discharge is generated between the main discharge electrodes E and E. The electric charge not consumed by the main discharge is transferred from the peaking capacitor Cp to the main capacitor C0 via the transfer capacitors C2, C1 and the regenerative transformer TC2, and is regenerated as a part of the next discharge energy. A reset current flows through each of the reset windings LR1 to LR3, TC1R, and TC2R. After the regeneration operation is completed, the voltages Vc1, Vc2, and Vcp of the transfer capacitors C1, C2 and the peaking capacitor Cp are caused by the reset current. Both rise from the negative side to the positive side.

  In the first invention, as shown in FIG. 3, at a predetermined time Tn after the main discharge (for example, Tn = 1 to 20 [mu] s, 20 to 30 [mu] s, 30 [mu] s to), the voltage upper limit value VLn (for example, Tn = 1 to 20 [mu] s) 0 V or less, Tn = 20 to 30 μs, 300 v or less, Tn = 30 μs to 500 v or less), and the voltage Vcp of the peaking capacitor Cp is less than the voltage upper limit value VLn set at each time Tn after the main discharge. Has been. Specifically, the following two measures are taken.

As a first means, as shown in FIG. 2, the primary winding TC11 and the secondary winding of the step-up transformer TC1 are set so that the voltage Vc1 of the transfer capacitor C1 at the first stage rises from negative after the completion of the regeneration operation. the turns ratio n _TC12 / n _TC11 line TC12, the turn ratio n _TC22 / n _TC21 primary winding TC21 and secondary winding TC22 regenerative transformer TC2, of the main capacitor C0 and the first stage of the transfer capacitor C1 The capacity ratio Cc0 / Cc1 is adjusted in advance (second invention).

More specifically,
(N _TC12 / n _TC11 )> √ (Cc0 / Cc1)
(N _TC22 / n _TC21 ) <√ (Cc0 / Cc1)
As relational expression is satisfied, the volume ratio of the turns ratio n _TC12 / n _TC11 and the turns ratio n _TC22 / n _TC21 regenerative transformer TC2, the main capacitor C0 and the first stage of the transfer capacitor C1 of the step-up transformer TC1 Cc0 / Cc1 is adjusted (fourth invention).

As a second means, the number of turns n _{TC12 of the} secondary winding TC12 of the boosting transformer TC1 and the number of turns n _{TC1R of the} reset winding TC1R are set so that the voltage rising speeds of the voltages Vc1, Vc2, and Vcp are below a predetermined speed. the number of turns n _TC2r turns n _TC22 and reset winding TC2r secondary winding TC22 regenerative transformer TC2, each transfer capacitor C1, C2 and peaking capacitance of Cp Cc1, ... Cck, and Ccp, but is preconditioned (Third invention).

More specifically, when the reset current flowing through the reset winding TC1R of the boosting transformer TC1 is ITC1R and the reset current flowing through the reset winding TC2R of the regenerative transformer TC2 is ITC2R,
_{{ITC1R × (n TC12 / n} TC1R) -ITC2R × (n TC22 / n TC2R)}
/(Cc1+...+Cck+Ccp) <K
_{(However, {ITC1R × (n TC12 /} n TC1R) -ITC2R × (n TC22 / n TC2R)}> is 0, K is a constant)
It made so that the relationship equation holds, the secondary winding and the number of turns n _TC1R turns n _TC12 and reset winding TC1R of TC12, turns n _TC22 and reset winding of the secondary winding TC22 regenerative transformer TC2 of the step-up transformer TC1 and the number of turns n _TC2r line TC2r, each transfer capacitor C1, ... Ck and peaking capacitance of Cp Cc1, ... Cck, and Ccp, but are previously adjusted (fifth invention).

  According to the present invention, by adjusting each element such as the number of windings of the boosting transformer and the number of windings of the regenerative transformer, the voltage rise of the peaking capacitor Cp after the main discharge is suppressed, and the peak value of the voltage Vcp is small. Therefore, the voltage Vcp tends to converge to 0. Accordingly, even in a laser device having a high repetition frequency, the voltage Vcp of the peaking capacitor Cp can be set to 0 during the magnetic pulse compression operation, and a good discharge can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Since the configuration of the power supply circuit in this embodiment is the same as that of the conventional power supply circuit shown in FIG. 4, the description of FIG. 4 described above will be used as the description of the circuit configuration of this embodiment.

  The greatest feature of this embodiment is that the primary winding TC11, the secondary winding TC12, and the reset winding TC1R in the step-up transformer TC1 are set so that the voltage Vcp of the peaking capacitor Cp after the main discharge is equal to or lower than the upper limit value VLn. The number of turns, the number of turns of the primary winding TC21, secondary winding TC22 and reset winding TC2R in the regenerative transformer TC2, and the capacities of the capacitors C1, C2, and Cp are adjusted in advance. is there.

  In the present embodiment, two measures are taken to suppress the voltage Vcp of the peaking capacitor Cp below the upper limit value VLn. The first means makes the voltage Vc1 of the first-stage transfer capacitor C1 negative after completion of the regenerative operation, and the second means suppresses the rising speed of the voltage Vcp of the peaking capacitor Cp after completion of the regenerative operation. Is the method.

Here, characters used in this specification are defined.
Cc0: Capacity of main capacitor C0 Cc1: Capacity of transfer capacitor C1 at the first stage Cc2: Capacity of transfer capacitor C2 at the second stage Ccn: Capacity of transfer capacitor Cn at the nth stage _nTC11 : _{Primary of} boosting transformer TC1 turns n _TC12 winding TC11: turns n _TC21 secondary winding TC12 of the step-up transformer TC1: turns n _TC22 of the primary winding TC21 regenerative transformer TC2: number of turns of the secondary winding TC22 regenerative transformer TC2 ITC1R: Current that flows in the reset winding TC1R of the boosting transformer TC1 ITC2R: Current that flows in the reset winding TC2R of the regenerative transformer TC2 ITC12: Current that flows in the secondary winding TC12 for boosting during magnetic reset ITC22: For regeneration during magnetic reset The current flowing in the secondary winding TC22 The first and second means will be described below.

First, in the first means, the turns ratio n _TC12 / n _{TC11 of the} primary winding TC11 and secondary winding TC12 of the step-up transformer TC1, and the primary winding TC21 and secondary winding _TC22 of the regeneration transformer TC2 are used. Turns ratio n _TC22 / n _TC21 and the capacitance ratio Cc 0 / Cc 1 of the main capacitor C 0 and the first-stage transfer capacitor C 1 are adjusted in advance.

  Here, in general, when charge is transferred between the primary side capacitor and the secondary side capacitor via the transformer, the turns ratio (n1 / n2) of the primary winding and the secondary winding of the transformer. And the capacitance ratio (C1 / C2) of the primary side capacitor and the secondary side capacitor will be considered. The following three relations are conceivable between (n2 / n1) and (C1 / C2).

The first relationship is
(N2 / n1) = √ (C1 / C2)
It is expressed by the following formula. When this equation holds, if the charge is transferred from the primary capacitor to the secondary capacitor, the voltage of the primary capacitor becomes 0 after the charge transfer. Conversely, when charge is transferred from the secondary side capacitor to the primary side capacitor, the voltage of the secondary side capacitor becomes 0 after the charge transfer. In a normal circuit, the winding ratio n1 / n2 and the capacitance ratio C1 / C2 are adjusted so that this relationship is established.

The second relationship is
(N2 / n1)> √ (C1 / C2)
It is expressed by the following formula. When this equation holds, if the charge is transferred from the primary capacitor to the secondary capacitor, the voltage of the primary capacitor becomes negative after the charge transfer. Conversely, when charge is transferred from the secondary capacitor to the primary capacitor, the secondary capacitor voltage becomes positive after the charge transfer.

The third relationship is
(N2 / n1) <√ (C1 / C2)
It is expressed by the following formula. When this equation holds, if the charge is transferred from the primary capacitor to the secondary capacitor, the voltage of the primary capacitor becomes positive after the charge transfer. Conversely, when charge is transferred from the secondary side capacitor to the primary side capacitor, the voltage of the secondary side capacitor becomes negative after the charge transfer.

In the present embodiment, after the regeneration operation is completed, that is, after the charge is transferred from the first-stage transfer capacitor C1 to the main capacitor C0 via the regeneration transformer TC2, the voltage of the first-stage transfer capacitor C1 is made negative. One of the purposes. Considering the above three relationships, the turn ratio n _TC22 / n _{TC21 of the} primary winding TC21 and secondary winding TC22 of the regenerative transformer TC2, and the capacitance ratio Cc0 of the main capacitor C0 and the first stage transfer capacitor C1 / Between Cc1
(N _TC22 / n _TC21 ) <√ (Cc0 / Cc1) (1)
It can be understood that the following relationship should be established.

Further, in the power supply circuit shown in FIG. 4, since the boosting transformer TC1 is connected in parallel with the regenerative transformer TC2, the primary winding TC11 of the boosting transformer TC1 is satisfied in order to satisfy the above equation (1). And the winding ratio n _TC12 / n _{TC11 of the} secondary winding TC12 and the capacitance ratio Cc0 / Cc1 of the main capacitor C0 and the transfer capacitor C1 of the first stage,
(N _TC12 / n _TC11 )> √ (Cc0 / Cc1) (2)
It is necessary to hold the relationship.

Accordingly, when the circuit is configured, the number of turns n _{TC11 of the} primary winding TC11 of the boosting transformer TC1, the number of turns n _{TC12 of the} secondary winding TC12 of the boosting transformer TC1, and the number of turns n of the primary winding TC21 of the regenerative transformer TC2. and _TC21, the number of turns n _TC22 secondary winding TC22 regenerative transformer TC2, the capacitance Cc1 of the first-stage transfer capacitor C1, the capacitance Cc0 of the main capacitor C0, but the (1), a (2) Adjusted to meet. This makes it possible to make the voltage of the transfer capacitor C1 in the first stage after completion of the regenerative operation negative.

Next, in the second means, the number of turns n _TC22 and resetting of the secondary winding TC22 turns n _TC12 and the number of turns n _TC1R the reset winding TC1R, regeneration transformer TC2 secondary winding TC12 of the step-up transformer TC1 The number of turns TC2R of the winding _TC2R and the capacitances Cc1,... Cck, Ccp of the transfer capacitors C1, C2 and the peaking capacitor Cp are adjusted in advance.

Each transformer TC1, TC2 is reset by a reset current together with each magnetic switch SR1-SR3. At this time, reset currents ITC1R and ITC2R flow through the reset windings TC1R and TC2R of the transformers TC1 and TC2, and accordingly, currents ITC12 and ITC22 flow through the secondary windings TC12 and TC22 of the transformers TC1 and TC2. In such cases, in general,
_{ITC12 = ITC1R × (n TC12 /} n TC1R)
ITC22 = ITC2R x ( _nTC22 / _nTC2R )
The relationship becomes true. Note that the reset current ITC1R flowing in the reset winding TC1R of the boosting transformer TC1 and the current ITC12 flowing in the secondary winding TC12 flow in the direction of positively charging the first-stage transfer capacitor C1. In addition, the reset current ITC2R flowing through the reset winding TC2R of the regeneration transformer TC2 and the current ITC22 flowing through the secondary winding TC22 flow in the direction of negatively charging the first-stage transfer capacitor C1.

In order to magnetically reset the step-up transformer TC1, it is necessary to positively charge the first-stage transfer capacitor C1. That is,
ITC12 -ITC22
_{= ITC1R × (n TC12 / n} TC1R) - ITC2R × (n TC22 / n TC2R)> 0
It is necessary to hold the relationship.

Further, the reset of the magnetic switches SR2 and SR3 performed after the main discharge is completed earlier than the reset of the boosting transformer TC1, and it is necessary to suppress the voltage rising speed of the peaking capacitor Cp to K (v / μs) or less. for that purpose,
(ITC12 -ITC22) / (Cc1 + Cc2 + Ccp)
_{= {ITC1R × (n TC12 /} n TC1R) -ITC2R × (n TC22 / n TC2R)}
/ (Cc1 + Cc2 + Ccp) <K (3)
To establish a relationship. Note that K is a constant, and a desired value may be obtained by experiment.

Therefore, the number of turns n _TC12 secondary winding TC12 of the step-up transformer TC1 during circuit configuration, a winding n _TC1R the reset winding TC1R of the step-up transformer TC1, turns n of the secondary winding TC22 regenerative transformer TC2 _TC22 , the winding n _TC2R of the reset winding TC2R of the regeneration transformer TC2, the capacitance Cc1 of the first-stage transfer capacitor C1, the capacitance Cc2 of the second-stage transfer capacitor C2, and the capacitance Ccp of the peaking capacitor Cp Are adjusted so as to satisfy the above expression (3). By doing so, the voltage rising speed of the peaking capacitor Cp after completion of the regenerative operation can be suppressed to less than K.

The power supply circuit of this embodiment includes a two-stage magnetic pulse compression circuit, but when the power supply circuit includes an n (n = 2 to k (k is 2 or more)) magnetic pulse compression circuit,
_{{ITC1R × (n TC12 / n} TC1R) -ITC2R × (n TC22 / n TC2R)}
/(Cc1+...+Cck+Ccp) <K ... (3) '
It is sufficient that the relationship is established.

Next, voltage characteristics obtained by this embodiment will be described.
FIG. 1 shows voltage characteristics of each capacitor during the magnetic pulse compression operation and the energy regeneration operation.
As shown in FIG. 1, the voltage characteristics generated in the magnetic pulse compression operation and the energy regeneration operation according to this embodiment are largely the same as the conventional voltage characteristics shown in FIG. Therefore, the basic flow of the magnetic pulse compression operation and the energy regeneration operation according to this embodiment is the same as the conventional one. The difference is that the voltage Vc0 of the main capacitor C0 becomes negative after the charge of the main capacitor C0 is transferred to the first-stage transfer capacitor C1 (a in FIG. 1), and the first-stage transfer capacitor C1. The voltage Vc1 of the first-stage transfer capacitor C1 becomes negative after the first charge is transferred to the main capacitor C0 (b in FIG. 1).

  The reason why the main capacitor C0 becomes negative after charge transfer as indicated by a in FIG. 1 is that each element is adjusted so as to satisfy the above equation (2). In addition, as indicated by b in FIG. 1, the first-stage transfer capacitor C1 becomes negative after charge transfer because each element is adjusted so as to satisfy the above equation (1).

FIG. 2 shows voltage characteristics of the capacitors C1, C2, and Cp after completion of the energy regeneration operation.
As shown in FIG. 2, the voltage Vc2 of the second stage transfer capacitor C2 and the voltage Vcp of the peaking capacitor Cp are substantially 0 at the timing of completion of the energy regeneration operation (a in FIG. 2). The voltage Vc1 of C1 is negative. The voltage Vcp and the voltage Vc2 decrease on the negative side with time, coincide with each other at the timing (b in FIG. 2) when the core of the magnetic switch SR3 is reset, and increase on the negative side. On the other hand, the voltage Vc1 rises on the negative side as time passes, falls again after turning to the positive side.

  Then, the voltages Vc1, Vc2, and Vcp rise together at the timing when the core of the magnetic switch SR2 is reset (c in FIG. 2), and rise together, and the timing when the core of the boosting transformer TC1 is reset (in FIG. 2) In d), the voltages Vc1, Vc2, and Vcp drop from the peak values. By setting each element so as to satisfy the above equation (3), it is possible to adjust the rising speed of the voltages Vc1, Vc2, and Vcp after the core of the magnetic switch SR2 is reset.

Here, the test conducted by the present inventors will be described.
The inventors set the voltage upper limit value VLn of the peaking capacitor Cp suitable for a high repetition frequency (6 KHz) as follows.

・ Upper limit VL10V in the period of 1μs ~ 20μs after main discharge
・ Upper limit VL2300V in the period from 20μs to 30μs after main discharge
・ Upper limit VL3500V for 30μs ~ after main discharge
The number of turns of each winding and the capacitance of the capacitor were adjusted based on the first and second means described above so as to satisfy the above conditions. At this time, the constant K in the above equation (3) is
K = 500 [V] / 40 [μs] = 12.5 [V / μs]
Set to. As a result, the voltage characteristic shown in FIG. 3 was obtained.

  FIG. 3 shows voltage characteristics of the peaking capacitor Cp measured before and after the main discharge. Immediately after the main discharge occurs (less than 1 μs), the voltage Vcp of the peaking capacitor Cp vibrates between positive and negative in a very short time. For this reason, in FIG. 3, the voltage characteristic immediately after the main discharge is generated is shown by a substantially vertical straight line.

  As shown in FIG. 3, the voltage Vcp of the peaking capacitor Cp is lower than the upper limit value VL1 (= 0V) in the period of 1 μs to 20 μs after the main discharge and the upper limit in the period of 20 μs to 30 μs after the main discharge, as set. The value is less than the value VL2 (= 300V), and less than the upper limit value VL3 (= 500V) in the period of 30 μs after the main discharge. That is, since the voltage rise of the peaking capacitor Cp after the main discharge is suppressed and the peak value of the voltage Vcp is suppressed, the voltage Vcp converges to 0 early as a result. Therefore, even with a high repetition frequency laser device, it is possible to obtain good discharge.

FIG. 1 is a diagram showing the voltage characteristics of each capacitor during the magnetic pulse compression operation and the energy regeneration operation obtained in this embodiment. FIG. 2 is a diagram illustrating voltage characteristics of the capacitors C1, C2, and Cp after completion of the energy regeneration operation. FIG. 3 is a diagram showing voltage characteristics of the peaking capacitor Cp measured before and after the main discharge. FIG. 4 is a diagram showing a power supply circuit of the gas laser device. FIG. 5 is a diagram showing the voltage characteristics of each capacitor during the magnetic pulse compression operation and the energy regeneration operation obtained in the conventional apparatus. FIG. 6 is a diagram showing a general configuration of a saturable reactor constituting the magnetic switch. FIG. 7 is a diagram showing the magnetization curve of the core of the saturable reactor constituting the magnetic switch.

Explanation of symbols

C0 ... Main capacitors C1, C2 ... Transfer capacitors Cp ... Peaking capacitors SR1, SR2, SR3 ... Magnetic switch TC1 ... Boosting transformer TC11 ... Primary winding TC12 ... Secondary winding TC1R ... Reset winding TR2 ... Regenerative transformer TC21 ... Primary winding TC22 ... Secondary winding TC2R ... Reset winding LR1, LR2, LR3 ... Reset winding HV ... High voltage power supply D1, D2 ... Diode E ... Main discharge electrode

Claims (6)

A main capacitor (C0) connected in parallel to a high voltage power supply (HV);
It has a primary winding for boosting (TC11) and a secondary winding for boosting (TC12), and the primary winding for boosting (TC11) has a magnetic assist (SR1) and a solid switch (SW) on the main capacitor (C0). ) Via a step-up transformer (TC1) connected in parallel via
It has a primary winding for regeneration (TC21) and a secondary winding for regeneration (TC22), and the primary winding for regeneration (TC21) is connected in parallel to the main capacitor (C0) via a diode (D1). Regenerative transformer (TC2),
A plurality of transfer capacitors (C1, C2) and magnetic switches (SR2, SR3), and the first-stage transfer capacitor (C1) is in parallel with the secondary winding for boosting (TC12) and the secondary winding for regeneration. N (n = 2 to k (k is 2 or more)) stage transfer capacitor (C2) connected in parallel to line (TC22) via diode (D2) and n−1 stage magnetic switch A magnetic pulse compression circuit connected in parallel to the transfer capacitor (C1) of the (n-1) th stage via (SR2);
A peaking capacitor (Cp) connected in parallel to the k-th transfer capacitor (C2) via the k-th magnetic switch (SR3) of the magnetic pulse compression circuit;
A pair of main discharge electrodes (E, E) connected in parallel to the peaking capacitor (Cp);
A magnetic assist reset winding (LR1) wound around the core of the magnetic assist (SR1) and resetting the operating point of the core in response to energization;
A magnetic switch reset winding (LR2) wound around the core of the n-th magnetic switch (SR2) and resetting the operating point of the core in response to energization;
A step-up transformer reset winding (TC1R) wound around the core of the step-up transformer (TC1) and resetting the operating point of the core in response to energization;
A regenerative transformer reset winding (TC2R) wound around the core of the regenerative transformer (TC2) and resetting the operating point of the core in response to energization;
With
The charges accumulated in the main capacitor (C0) by the high-voltage power supply (HV) are sequentially compressed through the step-up transformer (TC1) to the subsequent transfer capacitors (C1, C2) while the current pulse width is compressed. Then, it is further transferred to the peaking capacitor (Cp) to generate a main discharge between the main discharge electrodes (E, E). After the main discharge, electric charges are transferred from the peaking capacitor (Cp) to the transfer capacitors (C2) in the preceding stage. , C1), and further transferred to the main capacitor (C0) through the regenerative transformer (TC2) and the diode (D1) and regenerated by the main capacitor (C0). In
The voltage of the peaking capacitor (Cp) generated due to the current flowing through each of the reset windings (LR1, LR2, TC1R, TC2R) is set to increase stepwise with the passage of time after the main discharge. The power supply circuit of the gas laser device is characterized by being suppressed to an upper limit value or less. The turn ratio n _TC12 / n _{TC11 of the} boosting primary winding (TC11) and the boosting secondary winding (TC12) of the boosting transformer (TC1) and the primary winding for regeneration of the regenerative transformer (TC2) The turn ratio n _TC22 / n _{TC21 of the} wire (TC21) and the regenerative secondary winding (TC22) and the capacitance ratio Cc0 / Cc1 of the main capacitor (C0) and the first stage transfer capacitor (C1) The voltage Vc1 of the first stage transfer capacitor (C1) rises from negative after the charge is transferred in advance and transferred from the peaking capacitor (Cp) to the main capacitor (C0). The power circuit of the gas laser device according to claim 1. A main capacitor (C0) connected in parallel to a high voltage power supply (HV);
It has a primary winding for boosting (TC11) and a secondary winding for boosting (TC12), and the primary winding for boosting (TC11) has a magnetic assist (SR1) and a solid switch (SW) on the main capacitor (C0). ) Via a step-up transformer (TC1) connected in parallel via
It has a primary winding for regeneration (TC21) and a secondary winding for regeneration (TC22), and the primary winding for regeneration (TC21) is connected in parallel to the main capacitor (C0) via a diode (D1). Regenerative transformer (TC2),
A plurality of transfer capacitors (C1, C2) and magnetic switches (SR2, SR3), and the first-stage transfer capacitor (C1) is in parallel with the secondary winding for boosting (TC12) and the secondary winding for regeneration. The n-th stage magnetic switch is connected to the line (TC22) in parallel via a diode (D2), and the n-th (n = 2 to k (k is 2 or more)) stage transfer capacitor (C2). A magnetic pulse compression circuit connected in parallel to the transfer capacitor (C1) of the (n-1) th stage via (SR2);
A peaking capacitor (Cp) connected in parallel to the k-th transfer capacitor (C2) via the k-th magnetic switch (SR3) of the magnetic pulse compression circuit;
A pair of main discharge electrodes (E, E) connected in parallel to the peaking capacitor (Cp);
A magnetic assist reset winding (LR1) wound around the core of the magnetic assist (SR1) and resetting the operating point of the core in response to energization;
A magnetic switch reset winding (LR2) wound around the core of the n-th magnetic switch (SR2) and resetting the operating point of the core in response to energization;
A step-up transformer reset winding (TC1R) wound around the core of the step-up transformer (TC1) and resetting the operating point of the core in response to energization;
A regenerative transformer reset winding (TC2R) wound around the core of the regenerative transformer (TC2) and resetting the operating point of the core in response to energization;
With
The charges accumulated in the main capacitor (C0) by the high-voltage power supply (HV) are sequentially compressed through the step-up transformer (TC1) to the subsequent transfer capacitors (C1, C2) while the current pulse width is compressed. Then, it is further transferred to the peaking capacitor (Cp) to generate a main discharge between the main discharge electrodes (E, E). After the main discharge, electric charges are transferred from the peaking capacitor (Cp) to the transfer capacitors (C2) in the preceding stage. , C1), and further transferred to the main capacitor (C0) through the regenerative transformer (TC2) and the diode (D1) and regenerated by the main capacitor (C0). In
The turn ratio n of the boosting primary winding (TC11) and the boosting secondary winding (TC12) of the boosting transformer (TC1) _TC12 / N _TC11 And the turn ratio n of the primary winding (TC21) for regeneration and the secondary winding (TC22) for regeneration of the transformer for regeneration (TC2) _TC22 / N _TC21 And the capacitance ratio Cc0 / Cc1 of the main capacitor (C0) and the first-stage transfer capacitor (C1) are adjusted in advance, and the charge is transferred from the peaking capacitor (Cp) to the main capacitor (C0). After the transfer, the voltage Vc1 of the transfer capacitor (C1) at the first stage rises from negative.
A power supply circuit for a gas laser device. The number of turns n _TC12 of the step-up secondary winding (TC12) of the step-up transformer (TC1) and the number of turns n _{TC1R of the} step-up transformer reset winding (TC1R), and the regenerative secondary of the regenerative transformer (TC2) and the number of turns n _TC2r turns n _TC22 and the regeneration transformer reset winding windings (TC22) (TC2R), the capacity of each transfer capacitor (C1, C2) and the peaking capacitor (Cp) Cc1, ... Cck, Ccp Are adjusted in advance, and the voltage increase rate indicated by the voltage per unit time of the peaking capacitor (Cp) increases stepwise with the passage of time after the main discharge of the peaking capacitor (Cp). The power supply circuit for a gas laser device according to any one of claims 1 to 3, wherein the power supply circuit is configured to have a speed not exceeding an upper limit value of a voltage to be set . (N _TC12 / n _TC11 )> √ (Cc0 / Cc1)
(N _TC22 / n _TC21 ) <√ (Cc0 / Cc1)
Power supply circuit of the gas laser device according to claim 2 or 3, wherein the relational expression holds. When the reset current flowing in the boosting transformer reset winding (TC1R) is ITC1R and the reset current flowing in the regeneration transformer reset winding (TC2R) is ITC2R,
_{{ITC1R × (n TC12 / n} TC1R) -ITC2R × (n TC22 / n TC2R)}
/(Cc1+...+Cck+Ccp) <K
(However, {ITC1R × (n _TC12 / n _TC1R ) −TC2R × (n _TC22 / n _TC2R )}> 0, K is the voltage rise rate of the peaking capacitor (Cp), and is obtained by testing the power supply circuit. are constant)
The power supply circuit of the gas laser device according to claim 4, wherein:

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