JP2004356515A - High-voltage pulse generator with discharge-excited gas laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-voltage pulse generator which has high input energy and can correspond to a gas laser device for exposure which is subjected to high-repetition operation. <P>SOLUTION: A magnetic assist SR1 with a core formed by laminating a sheet-like core member, a step-up transformer Tr and magnetic switches SR2, SR3 are disposed inside a tank 10 filled with an insulating refrigerant 11. A cross flow fan 27 is also provided as a cooling fan. The spacing of core members of the magnetic assist SR1, the set-up transformer Tr and the magnetic switches SR1 to SR3 is set to ensure flow of insulating refrigerant so that a peripheral temperature is below a rated temperature of the core member in operation and the inductance in saturation of wiring equipment such as the magnetic switch or the like, which is a saturable reactor, is at most a prescribed value. For example, the spacing of the core members is set at 1.5 mm or more and 5 mm or less. A rotor diameter D of the cross flow fan 27 is set at 40≤D≤120 (mm). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
2. Description of the Related Art As a semiconductor integrated circuit is miniaturized and highly integrated, an improvement in resolution is required for a projection exposure apparatus for manufacturing the semiconductor integrated circuit. For this reason, the wavelength of exposure light emitted from an 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 semiconductor exposure light source. Further, as a next-generation semiconductor exposure light source, a 193 nm wavelength ArF excimer laser device and a 157 nm wavelength fluorine (F ₂ Gas laser devices that emit ultraviolet light, such as laser devices, are promising.
In a KrF excimer laser device, fluorine (F ₂ ) Gas, krypton (Kr) gas, and a mixed gas composed of a rare gas such as neon (Ne) as a buffer gas. In an ArF excimer laser apparatus, fluorine (F) is used. ₂ ) Gas, a mixed gas consisting of argon (Ar) gas and a rare gas such as neon (Ne) as a buffer gas; ₂ ) In a laser device, fluorine (F ₂ A) A laser gas, which is a laser medium, is excited by generating a discharge inside a laser chamber in which a laser gas, which is a mixed gas of a rare gas such as helium (He) as a gas and a buffer gas, is sealed at several hundred kPa. .
[0002]
Inside the laser chamber, a pair of main discharge electrodes for exciting a laser gas are opposed to 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 is broken down and the main discharge starts. The laser medium is excited by the main discharge.
Therefore, such an exposure gas laser device performs pulse oscillation by repetition of main discharge, and emitted laser light is pulsed light. At present, the repetition frequency of a laser pulse of a laser device used for exposure is about 2 kHz. However, in recent years, a repetition frequency of 4 kHz or more has been demanded in order to increase throughput and reduce variation in exposure amount.
[0003]
FIG. 7 shows an example of a high-voltage pulse generation circuit provided to generate a discharge in the laser chamber and excite the laser gas in the above-described exposure gas laser apparatus.
The high-voltage pulse generating circuit shown in FIG. 7 includes a two-stage magnetic pulse compression circuit using three magnetic switches SR1, SR2, and SR3 each composed of a saturable reactor. The magnetic switch SR1 is for reducing switching loss in the solid-state switch SW, which is a semiconductor switching element such as an IGBT, and is also called magnetic assist.
The first magnetic switch SR2 and the second magnetic switch SR3 constitute a two-stage magnetic pulse compression circuit.
Here, FIG. 7A shows a circuit including a step-up transformer Tr in addition to a magnetic compression circuit, and FIG. 7B does not include a step-up transformer and includes a reactor L1 for charging a capacitor C0 instead of the step-up transformer Tr. It is.
[0004]
Hereinafter, the configuration and operation of the circuit will be described with reference to FIG. Note that the circuit of FIG. 7B does not have the operation of boosting the voltage by the boosting transformer, and the other operations are the same as those of FIG. 7A.
First, the voltage of the high-voltage power supply CH is adjusted to 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 across the solid state switch SW is mainly applied across the magnetic switch SR1.
When the time integral of the charging voltage V0 of the main capacitor C0 applied to both ends of the magnetic switch SR1 reaches a limit value determined by the characteristics of the magnetic switch SR1, the magnetic switch SR1 is saturated and the magnetic switch is turned on, and the main capacitor C0 and the magnetic switch A current flows through SR1, the primary side of the step-up transformer Tr, and the loop of the solid state switch SW. At the same time, a current flows through the loop of the capacitor C1 on the secondary side of the step-up transformer Tr, and the electric charge stored in the main capacitor C0 transfers to charge the capacitor C1.
[0005]
Thereafter, when the time integral value of the voltage V1 at the capacitor C1 reaches a limit value determined by the characteristics of the magnetic switch SR2, the magnetic switch SR2 is saturated and the magnetic switch is turned on, and a loop of the capacitor C1, the capacitor C2, and the magnetic switch SR3 is formed. A current flows, and the electric charge stored in the capacitor C1 moves and charges the capacitor C2.
Thereafter, when the time integral of the voltage V2 at the capacitor C2 reaches a limit value determined by the characteristics of the magnetic switch SR3, the magnetic switch SR3 is saturated and the magnetic switch is turned on, and the capacitors C2, the peaking capacitor Cp, and the magnetic switch SR3 are turned on. A current flows through the loop, and the electric charge stored in the capacitor C2 transfers to charge the peaking capacitor Cp.
Corona discharge for preionization is generated on the outer peripheral surface of the dielectric tube 12 from a point where the dielectric tube 12 in which the first electrode 11 is inserted and the second electrode 13 are in contact with each other. As the charging of the capacitor Cp proceeds, the voltage Vp increases, and when Vp reaches a predetermined voltage, corona discharge occurs on the surface of the dielectric tube 12 of the corona preionization section. Ultraviolet rays are generated on the surface of the dielectric tube 12 by the corona discharge, and the laser gas 2 as a laser medium between the main discharge electrodes E1 and E2 is pre-ionized.
[0006]
As the charging of the peaking capacitor Cp further proceeds, the voltage Vp of the peaking capacitor Cp increases. When the voltage Vp reaches a certain value (breakdown voltage) Vb, the laser gas between the main discharge electrodes E1 and E2 is broken down. The main discharge starts, the laser medium is excited by the main discharge, and laser light is generated.
Thereafter, the voltage of the peaking capacitor Cp rapidly decreases due to the main discharge, and eventually returns to the state before the start of charging.
Such a discharge operation is repeatedly performed by the switching operation of the solid state switch SW, whereby pulse laser oscillation is performed at a predetermined repetition frequency.
[0007]
Here, in order to realize high repetition oscillation, the high voltage pulse applied to the main discharge electrodes E1 and E2 needs to have a fast rise and a short pulse.
The rise of the high-voltage pulse applied to the main discharge electrode is fast, that is, the energy transfer time to the peaking capacitor Cp (the transfer time of the charge from the capacitor C2 at the last stage of the magnetic pulse compression circuit in FIG. 7 to the peaking capacitor Cp) is short. If it is short, the discharge starting voltage can be increased, and the laser output can be increased.
In particular, a gas laser device that emits a laser beam having a shorter wavelength needs to input a larger amount of energy into a discharge space, and requires a high-voltage pulse that rises as fast as possible.
Further, excess current that cannot be transferred to the peaking capacitor Cp flows from the last stage capacitor (the capacitor C2 in FIG. 7) of the magnetic pulse compression circuit into the discharge space, but this excess current does not contribute to laser oscillation. Therefore, in the latter half of the discharge pulse, the discharge becomes non-uniform due to electric field concentration or the like, and a history that adversely affects the next pulse discharge remains.
As the repetition frequency increases, the pulse interval decreases, so that the possibility of being affected by the previous pulse discharge history increases. Therefore, in order not to be affected by the history, it is required that the charging time for the peaking capacitor Cp be as short as possible, that is, the high voltage pulse is a short pulse.
In the above-described circuit, by setting the inductance of the capacitance transition type circuit of each stage composed of the magnetic switches SR2 and SR3 and the capacitors C1 and C2 so as to become smaller toward the subsequent stage, the pulse of the current pulse flowing through each stage is set. A pulse compression operation is performed such that the width is gradually reduced, and a strong short-pulse discharge is realized between the main discharge electrodes E.
[0008]
FIG. 8 shows a configuration example of the magnetic switch. It is known that the performance (compression performance) of compressing the pulse width of the magnetic switches SR2 and SR3 in the circuit shown in FIG. 7 improves as the inductance after saturation of the magnetic switch decreases. In this configuration example, a plurality of windings of the capacitor and the core are provided in parallel to reduce the parasitic inductance of the capacitor and the inductance of the coil of the magnetic switch, thereby reducing the inductance after saturation of the magnetic switch.
For example, when FIG. 7 shows the magnetic switch SR3 (when SR (n + 1) in FIG. 7 is SR3), the capacitor Cn ₁ ~ Cn _n Is C2 ₁ ~ C2 _n And C2 ₁ ~ C2 _n C2 in FIGS. 7 (a) and 7 (b). At this time, the capacitor C2 ₁ ~ C2 _n Is connected to the ground side. One of the other ends is connected to C1 after the magnetic switch SR2 is wound a predetermined number of times. ₁ ~ C1 _n 7A and 7B are connected to the CH side, and the other end is wound SR3 a predetermined number of times, and then the peaking capacitor Cp ₁ ~ Cp _n When combined, it is connected to the CH side of Cp in FIGS. 7A and 7B.
Here, each magnetic switch and capacitor are installed in a tank (not shown) filled with an insulating refrigerant for cooling, for example, insulating oil. The insulating refrigerant flows on the core surface by natural convection or forced convection using a fan or the like, and performs heat exchange at that time.
[0009]
As described above, a repetition frequency of a laser pulse of a laser device used for exposure is required to be 4 kHz or more. Therefore, the amount of heat generated in the core of the magnetic switch increases. When a core corresponding to the current repetition frequency of 2 kHz is used, heat is generated in excess of the core rating.
As shown in FIG. 8, the core 1 is formed by winding a magnetic alloy ribbon around a core material 3 in an annual ring shape. This magnetic alloy ribbon is provided with an insulating thin film (eg, a silica thin film) on both surfaces. If the core generates more heat than rated, cracks occur in the silica thin film due to the difference in the coefficient of thermal expansion between the magnetic alloy ribbon and the silica thin film. When a crack is generated, a leakage current increases from the crack, further generates heat, and eventually loses characteristics as a circuit element.
As described above, the core 1 is formed by winding a magnetic alloy ribbon having a thin film of an insulator on both surfaces thereof in a ring shape around a core material. Therefore, the heat radiation performance of the core 1 is high on the surface parallel to the winding diameter direction of the magnetic alloy ribbon, and low on the surface perpendicular to the winding diameter direction.
The core corresponding to the high repetition frequency laser operation of the discharge excitation gas laser device shall adopt a structure in which the core is divided into thin plates and each thin core is arranged so as to be separated by a certain distance. There are many.
By adopting such a structure, the area of a portion which is in contact with the insulating refrigerant and has high heat dissipation performance is increased as compared with the structure of FIG.
Accordingly, the cooling efficiency of the core is increased, so that it is possible to cope with a high repetition frequency of 4 kHz or more in which the amount of generated heat increases.
[0010]
FIGS. 9A and 9B show an example of the configuration of the divided core structure as described above, which was proposed by the present inventors in Japanese Patent Application No. 2001-343534.
9 (a) and 9 (b), the annular support member 4 is inserted between the cores 1a to 1d formed by winding a magnetic alloy ribbon around the core material 3 in an annual ring shape. The cores 1a to 1d are held apart from each other by a predetermined distance. The diameter of the outer periphery of the support member 4 substantially matches the diameter of the outer periphery of the core material 3 of the cores 1a to 1d, and does not contact the cores 1a to 1d. The support member 4 is made of metal, for example, stainless steel (SUS316) steel.
Here, the support member 4 has annular projecting portions 4a whose diameter is smaller than the outer circumference on the upper and lower surfaces. A stepped portion 3a protruding toward the inner ring side of the core material of the cores 1a to 1d is provided so as to fit with the protruded portion 4a provided on the upper and lower surfaces of the support member 4. The cores 1a to 1d are positioned so as to be substantially coaxial by the protrusion 4a of the support member 4 and the step 3a of the core material 3.
The thickness of the cores 1a to 1d varies depending on the design conditions. For example, if the thickness is 10 mm or less, the core is bent by its own weight. In such a case, in order to prevent the core from bending due to its own weight, several bosses 5 are provided on the outer ring side surfaces of the cores 1a to 1d, and the rods 6 are made to pass through these bosses 5, and the bosses 5 and the rods 6 are stopped. Fix with screws 7.
In the above structure, the support member does not come into contact with the core (the magnetic alloy thin ribbon portion). Therefore, there is no portion where the flow of the refrigerant is obstructed on the core surface, and efficient heat exchange is possible even under a high repetition frequency condition of 4 kHz or more.
[0011]
[Problems to be solved by the invention]
As described above, in order to realize high repetition oscillation, the high voltage pulse applied to the main discharge electrodes E1 and E2 needs to have a fast rise and a short pulse.
In a magnetic pulse compression circuit that performs pulse compression for that purpose, it is desirable that the inductance after saturation of the magnetic switch be as small as possible in order to improve the compression efficiency.
If the inductance after saturation is small, the compression ratio cannot be increased.
Therefore, in order to obtain a voltage / current pulse having a desired pulse width, the number of stages of the magnetic pulse compression circuit is increased, or the number of turns of the saturable reactor constituting each magnetic switch of the magnetic pulse compression circuit around the core is increased. It is necessary to take measures to increase the compression ratio, such as reducing the diameter and increasing the cross-sectional area of the core. Therefore, the size of the magnetic pulse compression circuit becomes large, the maintenance becomes large, and the material cost of the magnetic pulse compression circuit itself increases.
Here, when the split core structure shown in FIG. 9 is adopted, the inductance of the winding wound around the core is larger than that of the core without the split structure. Therefore, the inductance of the magnetic switch after saturation cannot be reduced too much.
Conventionally, the distance between the cores has been set in consideration of only the heat radiation performance under the operating conditions of the magnetic switch that generates a large amount of heat. However, no consideration has been given to the problem of inductance that is unique when used in a high repetition rate laser device as described above.
Therefore, in some cases, the inductance of the magnetic switch after saturation did not decrease. Therefore, increase the number of stages of the magnetic pulse compression circuit, or reduce the number of turns of the saturable reactor constituting each magnetic switch of the magnetic pulse compression circuit around the core, thereby increasing the compression ratio such as increasing the cross-sectional area of the core. It was necessary to take measures to do so.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a high-voltage pulse generator capable of coping with a specific operating condition of an exposure gas laser device having a high input energy and performing a high repetition operation. To provide.
[0012]
[Means for Solving the Problems]
The present inventors have made intensive studies on the core structure in the gas laser apparatus for exposure, and as a result, determined the interval between the cores divided as described above to an appropriate value according to the repetition frequency, and also used for cooling. It has been found that if the rotor diameter of the cross flow fan is properly determined, the above-described problem of heat generation and the problem of inductance can be solved.
That is, in the present invention, the above-mentioned problem is solved as follows.
(1) At least one magnetic compression stage including a capacitor, a magnetic assist, and a magnetic switch is provided, and at least one of the magnetic assist and the magnetic switch is disposed in a container filled with an insulating refrigerant. The core of the arranged magnetic assist and magnetic switch has a structure in which a plurality of thin plate-shaped core members are laminated at predetermined intervals, and a fan for circulating an insulating refrigerant in the container is provided. In a high-voltage pulse generator for a discharge-excited gas laser device having a repetition frequency of operation of 4 kHz or more, the interval between the core members may be lower than the rated temperature of the core member during laser operation, and in a container that is a saturable reactor. It is set so that the inductance when the winding equipment is saturated is equal to or less than a predetermined value.
(2) In the high-voltage pulse generator for a discharge excitation gas laser device according to the above (1), which has a step-up transformer having a structure in which a plurality of thin plate-shaped core members are stacked at predetermined intervals, the distance between the core members of the step-up transformer is It is set to be equal to the above-mentioned set interval of the core member of the winding device arranged in the container.
(3) In the above (1) and (2), a cross flow fan is used as a fan. (4) In the above (3), a radiator for cooling the insulating refrigerant is provided at the inlet of the cross flow fan.
(5) In the above (3) and (4), the winding device or at least one of the winding device and the step-up transformer in the container may be provided with a surface parallel to a winding direction of a core magnetic alloy ribbon and a bottom surface of the container. Are arranged substantially perpendicular to each other, and the interval between the core members is set to 1.5 mm or more and 5 mm or less.
(6) In the above (3) and (4), the winding device or all of the winding device and the step-up transformer in the container may be configured such that the surface parallel to the winding diameter direction of the magnetic alloy ribbon of the core and the bottom surface of the container. The core members are arranged so as to be substantially parallel, and the interval between the core members is set to 2 mm or more and 5 mm or less.
(7) In the above (5) and (6), the rotor diameter of the cross flow fan is set to 40 mm or more and 120 mm or less.
In the present invention, in the high-voltage pulse generator for the discharge excitation gas laser device, the magnetic assist, the magnetic switch, and the interval between the core members of the step-up transformer are set as described above. Can be reduced to a desired value or less. Therefore, it is possible to cope with a high repetition frequency of 4 kHz or more at which the amount of heat generation increases without taking measures such as increasing the compression ratio.
In addition, since the rotor diameter of the cross flow fan is set as described above, it is possible to efficiently cool the core without increasing the number of rotations of the fan more than necessary or increasing the size of the fan. Become.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
FIGS. 1 and 2 are views showing the overall configuration of a high-voltage pulse generator according to a first embodiment of the present invention, in which a magnetic switch, a step-up transformer, a capacitor and the like are installed in a tank filled with an insulating refrigerant. The following shows an example of the arrangement. FIG. 2 is a sectional view taken along line AA of FIG. 1, but for convenience of explanation, the radiator is shown at a position different from that of FIG. 1, and some other members are provided for easy understanding. Are displayed differently from FIG.
In FIG. 1 and FIG. 2, a final-stage magnetic switch SR3 having a racetrack-shaped core is provided at the lowest stage inside the tank 10. The surface of the core of the magnetic switch SR3 that is parallel to the winding diameter direction of the magnetic alloy ribbon faces the bottom surface of the tank 10, and the longitudinal direction of the core and the main electrodes E1 and E2 provided in the laser chamber 20 correspond to each other. The longitudinal directions are substantially the same. The core of the magnetic switch SR3 is divided as shown in FIG. 9 in order to improve the efficiency of heat exchange with the insulating refrigerant 11.
On both sides of the magnetic switch SR3, a plurality of capacitors C2 are arranged along the longitudinal direction of the main electrodes E1 and E2. The plurality of capacitors C2 are supported by a conductive support member 21 (FIG. 2) provided at one end.
[0014]
Above the magnetic switch SR3, a magnetic assist SR1, which has a substantially circular core, a step-up transformer Tr, and a magnetic switch SR2, respectively, make the axial direction of the core substantially coincide with the longitudinal direction of the main electrodes E1, E2, and The cores are arranged so that their central axes are substantially aligned. Similarly to the magnetic switch SR3, the cores of the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2 are divided.
On both sides of the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2, a plurality of capacitors C1 are arranged along the longitudinal direction of the main electrodes E1 and E2 provided in the laser chamber 20. The plurality of capacitors C1 are supported by a conductive support member 22 (FIG. 2) provided at one end. The other end is connected by a conductive connection member 23 (FIG. 2). In FIG. 2, for the sake of explanation, the conductive support member 22 is drawn so as to be bent right and left in the figure. However, in reality, as shown schematically in FIG. 1, it is bent outside the capacitor C2.
A negative high voltage is supplied to the main electrode E1 by a negative high voltage introducing member 25 penetrating the insulating material 24 provided on the bottom surface of the tank 10.
[0015]
Conventionally, a heat exchanger 26 (hereinafter, referred to as a radiator) for cooling the insulating refrigerant has been provided above the core inside the tank 10. Cooling water from the outside is introduced and discharged into the radiator 26 (FIG. 2 shows a state in which the radiator 26 is arranged above the core as described above).
The insulating refrigerant near the radiator 26 is cooled, and the insulating refrigerant 11 near the magnetic switches SR1 to SR3, the transformer Tr, and the capacitors C1 and C2 is heated during operation of the laser device.
Therefore, natural convection of the insulating refrigerant 11 occurs due to the temperature difference. The insulating refrigerant 11 flows on the surfaces of the magnetic switches SR1 to SR3 and the cores of the transformer Tr and the surfaces of the capacitors C1 and C2 by natural convection, and the heat exchange performed at that time causes the magnetic switches SR1 to SR3, the transformer Tr and the capacitor C1. , C2 are cooled.
[0016]
However, as described above, in recent years, a repetition frequency of 4 kHz or more has been demanded in order to increase the throughput and reduce the variation in the exposure amount. Under such operating conditions, self-heating in the cores of the magnetic switches SR1 to SR3 and the transformer Tr increases, which may exceed the rating of the core, and the temperature of the insulating refrigerant 11 also increases.
When the cores of the magnetic switches SR1 to SR3 and the transformer Tr are simply immersed in the insulating refrigerant 11 and the radiator 26 also immersed in the insulating refrigerant is provided and cooled by heat exchange by natural convection of the insulating refrigerant, the radiator 26 is enlarged. Therefore, the size of the tank 10 is increased.
Therefore, it is desirable to provide a cooling fan inside the tank 10 and force the convection of the insulating refrigerant inside the tank 10. Thereby, the flow velocity of the insulating refrigerant flowing on the surfaces of the magnetic switches SR1 to SR3, the core of the transformer Tr, the surfaces of the capacitors C1 and C2, and the surface of the radiator 26 increases.
Therefore, the heat exchange efficiency is increased, so that even under the operating condition of the repetition frequency of 4 kHz or more, the radiator 26 is prevented from being enlarged to some extent as compared with the natural convection, and the magnetic switches SR1 to SR3, the transformer Tr, the capacitor C1, C2 can be cooled.
[0017]
In FIG. 1, a cross flow fan 27 is used as the cooling fan. The cross flow fan 27 is disposed so that its longitudinal direction is substantially parallel to the longitudinal direction of the elliptical core of the magnetic switch SR3. The length of the fan 27 in the longitudinal direction is set to be substantially equal to or longer than the longitudinal length of the core of the magnetic switch SR3.
Note that the cooling fan is not limited to the crossflow fan, and for example, a plurality of axial fans may be provided in the longitudinal direction of the core of the magnetic switch SR3.
However, if the cooling fan is a cross-flow fan, the flow velocity of the insulating refrigerant near the elliptical core of the magnetic switch SR3, which is not uniform in the axial fan, can be made substantially uniform, and the temperature distribution of the core becomes low. It became almost uniform. Further, the flow rates of the insulating refrigerant flowing on the surfaces of the respective cores of the magnetic assist SR1, the magnetic switch SR2, and the step-up transformer Tr can be made substantially uniform, and the temperatures of the respective cores become substantially uniform.
[0018]
When the cross flow fan 27 is used, a radiator may be arranged below the liquid level of the insulating refrigerant in the upper part of the tank 10 as shown in FIG. 2, but as shown in FIG. Preferably, it is located near the intake.
That is, the casing made by the guide of the cross flow fan 27 is configured such that the fluid (insulating refrigerant 11) flows in from above as shown in FIG. With this configuration, the flow velocity near the fluid inlet above the fan 27 is the fastest. This position is also where the fluid flows after being heated. That is, it becomes possible to arrange the radiator 26 at a position where the flow velocity after heating by heat exchange with the core and the condenser of the insulating refrigerant 11 is fast.
Further, since the flow velocity is high, the heat exchange efficiency is improved as compared with the case where the insulating refrigerant 11 is disposed below the liquid level in the upper part of the conventional tank 10. Therefore, the radiator 26 can be reduced in size.
Here, since the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2 are arranged as described above, the flow of the insulating refrigerant flows between the cores, that is, the surface parallel to the winding diameter direction of the magnetic alloy ribbon. Pass in parallel. As described above, since the heat dissipation performance of the core is high on the surface parallel to the winding diameter direction of the magnetic alloy ribbon, heat can be efficiently removed by the insulating refrigerant passing through this surface, and suitable cooling can be achieved. It is possible.
[0019]
In the present embodiment, the optimum value of the interval d between the cores of the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2 in the high voltage pulse generator having the above configuration was examined as follows.
First, the core temperature corresponding to the interval d between the divided cores was measured. The result is shown in FIG. Here, the measured core is the core of the magnetic switch SR2.
The repetition frequency of the laser operation is 2, 4, and 6 kHz. The horizontal axis in FIG. 3 is the core interval d, the vertical axis is the temperature T, and Ts is the rated temperature of the core.
As shown in FIG. 3, as the repetition frequency increases, the core interval d for realizing the core rated temperature Ts increases. However, when the distance exceeds a certain core interval, the heat radiation performance of the core is saturated, and the temperature of the core does not change.
Therefore, in the case of the repetition frequency of 4 kHz, the core interval is set to the core interval d at the rated temperature Ts of the core. _T4 Set above. Here, in order to allow a margin for cooling, for example, the core interval d at the rated temperature Ts in the case of a repetition frequency of 6 kHz _T6 Set above.
[0020]
Further, the present inventors have examined the relationship between the maximum value L of the inductance after saturation of the magnetic switch and the core interval d, which are allowed to realize a short pulse. FIG. 4 shows the results. The horizontal axis in FIG. 4 is the core interval d, and the vertical axis is the inductance L.
As is clear from FIG. 4, the higher the repetition frequency, the smaller the allowable maximum value L of the inductance after saturation of the magnetic switch, and the smaller the core interval d corresponding thereto. When the repetition frequency is 4 kHz or more, the core interval is set to d. _L6 Set as follows.
From the above, when the repetition frequency is 4 kHz or more, the core interval d is d _T6 Above, d _L6 It can be seen that it is desirable to set the following.
In our experiments, d _T6 = 1.5 mm, d _L6 = 5 mm. Therefore, when the repetition frequency is 4 kHz or more, it is desirable that the core interval be 1.5 mm or more and 5 mm or less.
[0021]
Next, a second embodiment of the present invention will be described.
In the first embodiment, the surfaces of the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2, which are parallel to the winding diameter direction of the magnetic alloy ribbon, are parallel to the flow of the insulating refrigerant. In FIG. 5, as shown in FIG. 5, the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2 of the high-voltage pulse generator are arranged in the same direction as the magnetic switch SR3.
FIG. 5 shows a configuration corresponding to FIG. 1, and the same components as those shown in FIG. 1 are denoted by the same reference numerals.
As shown in the figure, in the present embodiment, the surface parallel to the winding diameter direction of the magnetic alloy SR1 and the step-up transformer Tr, and the magnetic alloy thin strips of the magnetic switch SR2 and the magnetic switch SR3 are connected to the bottom surface of the tank 10. They are arranged to face each other. Further, each core is divided as described above, and the cores are arranged so as to be substantially coincident with each other.
The core of the magnetic switch SR3 may be an elliptical core as in FIG. 1, or may be a circular core as in the magnetic switch SR2 and the like.
[0022]
A plurality of capacitors C2 are arranged on both sides of the magnetic switch SR3 along the longitudinal direction of the main electrodes E1 and E2, as in the first embodiment. The plurality of capacitors C2 are supported by the conductive support members as described above.
On both sides of the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2, a plurality of capacitors C1 are arranged along the longitudinal direction of the main electrodes E1 and E2. As described above, the plurality of capacitors C1 are supported by the conductive support member, and the other ends are connected by the conductive connection member.
A negative high voltage is supplied to the electrode E1 by a negative high voltage introducing member 25 that penetrates the insulating material 24 provided on the bottom surface of the tank 10.
Further, a cross flow fan 27 is provided as a cooling fan, and the cross flow fan 27 is arranged so that its longitudinal direction is substantially parallel to the core of the magnetic switch SR3. The length of the fan 27 in the longitudinal direction is set to be substantially equal to or longer than the diameter of the core of the magnetic switch SR3 or the length in the longitudinal direction.
Further, a radiator 26 is arranged near the intake of the insulating refrigerant 11 of the cross flow fan 27.
[0023]
In this embodiment, as shown in FIG. 5, all the surfaces of the magnetic alloy ribbon of each core parallel to the winding diameter direction are arranged in the direction facing the flow direction of the insulating refrigerant. Therefore, the heat radiation performance of the core is lower than that of the first embodiment.
Regarding the high voltage pulse generator having the above configuration, the optimum value of the interval d between the cores of the magnetic assist SR1, the step-up transformer Tr, and the magnetic switch SR2 was examined in the same manner as described above. As a result, in the configuration of this embodiment, d _T6 = 2mm, d _L6 = 5 mm. Therefore, when the repetition frequency is 4 kHz or more, it is desirable that the core interval be 2 mm or more and 5 mm or less.
Next, in the configurations of the first and second embodiments, the peripheral speed of the cross flow fan 27 and the core interval d at which the rated temperature Ts is reached are set. _TS And examined the relationship.
FIG. 6 shows the result. Here, the measurement target of the core interval is the core of the magnetic switch SR2, the repetition frequency of the laser operation is 4 kHz, and the diameter of the impeller (rotor) of the cross flow fan is 80 mm. The horizontal axis of the figure is the peripheral speed V (m / S) of the cross flow fan, and the vertical axis is the core interval d. _TS It is.
As shown in the figure, as the peripheral speed of the crossflow fan increases, the core interval d at which the core temperature reaches the rated temperature Ts is obtained. _TS Gradually narrows. This is presumably because as the peripheral speed of the fan increases, the speed of the insulating refrigerant flowing between the cores increases, and the heat exchange efficiency increases.
However, when the peripheral speed is equal to or higher than Vmax, the core interval d _TS Is d _Tmax Does not change much. Although the cause is not clear, it is considered that the flow of the insulating refrigerant when the insulating refrigerant collides with the side surface of the core becomes large and the speed of the insulating refrigerant flowing between the cores is restricted.
[0024]
The core interval shown in the first and second embodiments is a characteristic when the peripheral speed is Vmax. Here, in the case of 4 kHz, Vmax was 0.8 m / s or more.
In addition, when the rotor diameter of the cross flow fan is smaller than 40 mm, when trying to realize Vmax = 0.8 m / s, the rotation speed of the fan becomes too high and the load of the motor for rotating the cross flow fan becomes large, which is not preferable. Was.
Further, when the rotor diameter of the cross flow fan is larger than 120 mm, the tank accommodating the cross flow fan becomes too large, which is not preferable.
Therefore, it was found that when the frequency is 4 kHz or more, the rotor diameter D of the cross flow fan is preferably 40 ≦ D ≦ 120 (mm).
[0025]
【The invention's effect】
As described above, in the present invention, the following effects can be obtained.
(1) In the high-voltage pulse generator for the discharge excitation gas laser device, since the distance between the core members of the magnetic assist, the magnetic switch, and the step-up transformer is set as described above, the inductance of the winding is reduced while increasing the core cooling efficiency. It can be less than the desired value.
For this reason, it is possible to cope with a high repetition frequency of 4 kHz or more in which the amount of generated heat increases without taking measures such as increasing the compression ratio. Can respond to
(2) Since the rotor diameter of the cross flow fan is set as described above, the core can be efficiently cooled without increasing the number of rotations of the fan more than necessary or increasing the size of the fan. It becomes.
[Brief description of the drawings]
FIG. 1 is a diagram (1) illustrating an overall configuration of a high-voltage pulse generator according to a first embodiment of the present invention.
FIG. 2 is a diagram (2) illustrating the overall configuration of the high-voltage pulse generator according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a measurement result of an interval d between divided cores and a temperature of the core;
FIG. 4 is a diagram illustrating a relationship between a maximum value L of an inductance and a core interval d.
FIG. 5 is a diagram showing an overall configuration of a high-voltage pulse generator according to a second embodiment of the present invention.
FIG. 6 is a diagram illustrating a relationship between a peripheral speed of a cross flow fan and a core interval at a rated temperature.
FIG. 7 is a diagram illustrating an example of a high voltage pulse generation circuit.
FIG. 8 is a diagram illustrating a configuration example of a magnetic switch.
FIG. 9 is a diagram showing a configuration example of a divided core structure.
[Explanation of symbols]
10 tanks
11 Insulating refrigerant
20 Laser chamber
21,22 Conductive support member
23 conductive connecting members
24 Insulation
25 Negative high voltage introduction member
26 radiator (heat exchanger)
27 Cross Flow Fan
C1, C2 capacitor
E1, E2 main electrode
SR3 Magnetic switch
SR1 Magnetic assist
SR2 Magnetic switch
Tr step-up transformer

Claims (7)

A main capacitor charged to at least a high voltage, a magnetic assist including a saturable reactor, and a pulse generation circuit including switch means;
A magnetic pulse compression circuit having at least one magnetic compression stage composed of a capacitor and a magnetic switch composed of a saturable reactor and connected to an output terminal of the pulse generation circuit;
A high-voltage pulse generator for a discharge-excited gas laser device, wherein a pair of electrodes arranged in at least a laser chamber are connected to an output end of the magnetic pulse compression circuit,
The magnetic assist and the magnetic switch are winding devices in which a winding is wound around a core formed by winding a magnetic alloy ribbon around an annular winding core,
At least one of the magnetic assist and the magnetic switch is disposed in a container filled with an insulating refrigerant, and a plurality of thin plate-shaped core members are provided at predetermined intervals in a core of the winding device disposed in the container. It is a structure laminated on
Further, in the high voltage pulse generator for the discharge excitation gas laser device provided with a fan for circulating the insulating refrigerant in the container,
The repetition frequency of the laser operation of the discharge excitation gas laser device is 4 kHz or more, the temperature is lower than the rated temperature of the core member during the laser operation, and the inductance when the winding device in the container which is a saturable reactor is saturated is predetermined. A high-voltage pulse generator for a discharge-excited gas laser device, wherein the interval between the core members is set so as to be equal to or less than the value. The high voltage pulse generator for a discharge excitation gas laser device has a step-up transformer for stepping up a voltage pulse generated in a pulse generation circuit, and the step-up transformer has a structure in which a plurality of thin plate-shaped core members are stacked at predetermined intervals. And is disposed in the container,
2. The high voltage pulse generator for a discharge excitation gas laser device according to claim 1, wherein the interval between the core members of the step-up transformer is equal to the set interval between the core members of the winding device arranged in the container. 3. The high voltage pulse generator for a discharge excitation gas laser device according to claim 1, wherein a cross flow fan is used as said fan. 4. The high voltage pulse generator for a discharge excitation gas laser device according to claim 3, wherein a radiator for cooling the insulating refrigerant is provided at an inlet of the cross flow fan. At least one of the winding device or the winding device and the step-up transformer in the container is arranged such that a surface parallel to the winding diameter direction of the magnetic alloy ribbon of the core and a bottom surface of the container are substantially perpendicular to each other,
5. The high-voltage pulse generator for a discharge-excited gas laser device according to claim 3, wherein an interval between the core members is set to 1.5 mm or more and 5 mm or less. All of the winding device or the winding device and the step-up transformer in the container are arranged such that the surface parallel to the winding diameter direction of the magnetic alloy ribbon of the core and the bottom surface of the container are substantially parallel,
5. The high-voltage pulse generator for a discharge-excited gas laser device according to claim 3, wherein an interval between the core members is set to 2 mm or more and 5 mm or less. 7. The high-voltage pulse generator for a discharge-excited gas laser device according to claim 5, wherein a rotor diameter of the cross flow fan is set to 40 mm or more and 120 mm or less.

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