JP2001320112A - Discharge-excited pump laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge-excited pump laser device wherein a stable beam profile can be obtained by stabilizing the shape of a discharge space. SOLUTION: In this discharge-excited pump laser device, main electrodes (5A, 5B) which are arranged sandwiching the discharge space (16) and excite laser medium by generating main discharge (35) between the electrodes are installed. An electric field control electrode (37) is arranged in a side part of the discharge space (16), almost parallel with the main electrodes (5A, 5B) in the longitudinal direction, and an electric field control voltage (-VE) which shuts electrons in the discharge space (16) into the inside is applied to the electric field control electrode (37). The discharge-excited pump laser device is a pulse laser equipment, and the electric field control voltage (-VE) is changed in accordance with oscillating frequency of pulse oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge excitation laser device for exciting a laser medium by electric discharge.

[0002]

2. Description of the Related Art Heretofore, in a discharge excitation laser apparatus for exciting a laser medium by electric discharge, there has been known a problem that a sectional shape of a laser beam (this is called a beam profile) fluctuates as a main electrode is consumed. I have. One example of a technique for solving this problem is disclosed in Japanese Patent Application Laid-Open No. 4-101476. FIG. 10 shows an excimer laser device disclosed in the publication. In FIG. 10, an excimer laser device 1 includes a laser chamber 2 in which a laser gas is sealed at a predetermined pressure ratio. Laser chamber 2
Are provided with main electrodes 5A and 5B each composed of an anode 5A and a cathode 5B so as to face in a direction perpendicular to the plane of the drawing. Then, a high voltage is applied to the main electrodes 5A and 5B from a high-voltage power supply (not shown) to cause a discharge, thereby exciting the laser medium and causing the laser light 11 to oscillate.

The laser light 1 generated in the laser chamber 2
1 is emitted backward (leftward in the figure) from the rear window 9 and narrowed by the grating 23 so that the spectrum width of the oscillation wavelength becomes narrow. The narrowed laser light 11 is transmitted from the rear window 9 to the laser chamber 2.
Again, passes through the front window 7 and the front mirror 8, exits from the excimer laser device 1, and becomes a processing light source for a semiconductor processing device such as a stepper (not shown). At this time, a slit 48 having an opening 45 is provided before and after the laser chamber 2. This slit 48
Thereby, the beam width of the laser light 11 is limited to the width of the opening 45, so that the oscillation spectrum when the laser light 11 is narrowed becomes narrower.

FIG. 11 shows a detailed view of the electrode disclosed in the publication. In FIG. 11, a high voltage is applied from a high-voltage power supply (not shown) between a cathode 5B and an anode 5A which are installed facing each other in the vertical direction, to cause a main discharge 35 to oscillate the laser beam 11. The area where the main discharge 35 occurs
It is called a discharge space 16. At this time, the gas flow 36 flows from left to right. At this time, on both sides of at least one of the cathode 5B and the anode 5A, an electric field relaxation bar 46 composed of a metal electrode 46A and a ceramic material 46B such as alumina ceramic covering the periphery thereof is provided. The metal electrode 46A has the same potential as the main electrodes 5A and 5B and electrostatically holds the potential. Even when the main electrodes 5A and 5B are consumed, the lines of electric force 47 in the discharge space 16 become substantially parallel. To make the electric field uniform. This electric field relaxation bar 4
6, the discharge space 1 due to the consumption of the main electrodes 5A and 5B.
6 is prevented from expanding in the left-right direction in the figure, and the beam profile is stabilized.

[0005]

However, the prior art has the following problems. In other words, with the recent demand for higher integration of semiconductors, there is a demand for improving the resolution of semiconductor processing equipment and performing finer processing. For that purpose, it is necessary to stabilize the beam profile of the laser beam 11 as the processing light source with higher accuracy. In order to stabilize such a highly accurate beam profile, it is not sufficient to prevent the expansion of the discharge space 16 when the main electrodes 5A and 5B are consumed by the electric field relaxation bar 46. Is needed.

The expansion and fluctuation of the discharge space 16 are caused not only by the consumption of the main electrodes 5A and 5B, but also by the deterioration of the laser gas discharge and the accompanying main electrodes 5A and 5B.
It also occurs due to the fluctuation of the high voltage applied between B and the like. Therefore, there are cases where expansion and fluctuation of the discharge space 16 cannot be sufficiently suppressed only by the electric field relaxation bar 46. Further, the discharge space 16 may move in the direction in which the gas flow 36 flows, thereby causing the laser light 11 to be misaligned with respect to an optical component such as the front mirror 8, and
Power is reduced. Depending on the electric field relaxation bar 46, it is difficult to prevent such a movement of the discharge space 16.

Further, in order to improve the resolution of the semiconductor processing apparatus, it is required to make the oscillation spectrum width of the laser beam 11 narrower. For that, slit 4
It is necessary to narrow the beam width of the laser beam 11 by limiting the beam width by 8 and narrow the beam divergence angle. However, when the discharge space 16 is wider than the width of the opening 45 of the slit 48, the discharge space 16 outside the width of the opening 45 and not contributing to laser oscillation becomes larger, and the excimer laser device 1 Energy efficiency is reduced. In order to prevent this, the main discharge 35 is performed in the narrow discharge space 16 using the narrow main electrodes 5A and 5B. However, such a narrow main electrode 5
When A and 5B are used, it is difficult to suppress the discharge space 16 from being wider than the width of the main electrodes 5A and 5B depending on the function of only the electric field relaxation bar 46. Therefore, there is a problem that the energy that contributes to the oscillation of the laser beam 11 among the energy input for the main discharge 35 is reduced, and the energy efficiency is reduced. Furthermore, since it is difficult to suppress the width of the discharge space 16 by the electric field relaxation bar 46, there is a problem that the beam profile tends to be unstable.

The present invention has been made in view of the above problems, and has as its object to provide a discharge excitation laser device capable of stabilizing the shape of a discharge space and obtaining a stable beam profile. I have.

[0009]

In order to achieve the above object, the present invention provides an electric field control electrode on the side of a discharge space of a discharge excitation laser device substantially in parallel with a main electrode in a longitudinal direction. Have. If, for example, an electric field control voltage for pushing electrons is applied to such an electric field control electrode, the electrons moving in the discharge space are pushed into the discharge space by the repulsive force, and the expansion of the discharge space in the left-right direction is suppressed. Thereby, the fluctuation of the beam profile becomes smaller, and a stable beam profile is obtained. This also makes it possible to make the width of the discharge space almost the same as the beam width of the oscillated laser light. That is,
Since the discharge space outside the beam width of the laser beam and not contributing to the oscillation is reduced, the ratio of the energy contributing to the oscillation of the laser beam is increased, and the efficiency of the laser device is increased.
In particular, when a narrow main electrode is used, the width of the discharge space is likely to be widened. By suppressing the width, the effect of improving energy efficiency is great.

The present invention also provides a pulse laser device,
The electric field control voltage applied to the electric field control electrode is changed according to the oscillation condition or the state thereof, such as the oscillation frequency of the laser beam. That is, in the pulse laser device, for example, a phenomenon in which the discharge space moves when the oscillation frequency changes is seen, which leads to a change in the beam profile and a decrease in the power of the laser beam. Since the moving distance of the discharge space substantially corresponds to the oscillation frequency, it is possible to suppress this movement by changing the electric field control voltage applied to the electric field control electrode according to the oscillation frequency.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings. In each embodiment, the same reference numerals are given to the same elements as those used in the description of the related art and the drawings used in the description of the embodiment earlier than the embodiment, and the overlapping description will be omitted. I do.

First, a first embodiment will be described. FIG.
FIG. 2 is a plan view of the excimer laser device according to the present embodiment, and FIG. In the following description, the direction perpendicular to the plane of the paper in FIG. 2 is the longitudinal direction,
The vertical direction in the figure, which is perpendicular to the longitudinal direction and the gas flow direction, is called the vertical direction.

1 and 2, an excimer laser apparatus 1 includes a laser chamber 2 in which a laser gas containing, for example, fluorine (F 2), krypton (Kr), and neon (Ne) is sealed at a predetermined pressure ratio. ing. Inside the laser chamber 2, main electrodes 5A and 5B composed of an anode 5A and a cathode 5B are disposed so as to be opposed to each other in the vertical direction with the discharge space 16 interposed therebetween. The laser gas is applied to the main electrode 5
The laser beam 11 is excited in the discharge space 16 by the main discharge 35 between A and 5B, and generates a laser beam 11 in the longitudinal direction.

The generated laser beam 11 is emitted backward (leftward in FIG. 1) from the rear window 9 and
To the band narrowing unit 20 provided on the outside rear side of the. The beam width of the laser light 11 is expanded by the prisms 22 and 22 inside the laser light 11, and the spectral width of the oscillation wavelength is narrowed by the grating 23. The narrowed laser light 11 re-enters the laser chamber 2 from the rear window 9 and exits from the front window 7 and the front mirror 8. At this time, the laser chamber 2
Before and after, slits 48, 48 having an opening 45 are provided. Thereby, the beam width of the oscillating laser light 11 is reduced to the width of the opening 45, and the laser light 11
By reducing the divergence angle, the oscillation spectrum when the band is narrowed is made narrower.

As shown in FIG. 2, inside the laser chamber 2, a through-flow fan 14 for circulating the laser gas inside the laser chamber 2 and sending it to the discharge space 16 is provided for cooling the laser gas heated by the discharge. And the heat exchangers 3 are respectively provided at predetermined positions. The gas flow 36 of the laser gas at this time is represented by an arrow, and flows in the discharge space 16 from left to right in the figure. The left side in the figure with respect to the discharge space 16 is called the upstream side, and the right side is called the downstream side. On the side of the anode 5A, a preliminary ionization electrode 18 composed of a rod-shaped internal conductor 26 made of copper or the like and a dielectric 27 surrounding the outer periphery is provided. On the upstream side and the downstream side of the gas flow 36 at a substantially middle position in the vertical direction between the main electrodes 5A, 5B, electric field control electrodes 37, 37 formed of rod-shaped conductors made of copper or the like are provided. They are arranged substantially parallel to the main electrodes 5A and 5B in the longitudinal direction.

FIG. 3 is a charge / discharge circuit diagram of the excimer laser device, and FIG. 4 is an enlarged view of the vicinity of the discharge space. In FIG. 3, the charge / discharge circuit includes a high-voltage power supply 13, a saturable reactor L,
It has a capacitor C2, a main discharge capacitor Cp1, and a preliminary discharge capacitor Cp2. The anode 5A is on the ground side (GND) of the high voltage power supply 13, the cathode 5B is on the high voltage side (-V) of the high voltage power supply 13, and the internal conductor 26 is on the high voltage side of the high voltage power supply 13 via the preliminary discharge capacitor Cp2. (-V). Further, the electric field control electrodes 37, 37 are connected to the negative high voltage (-VE) of the external power supply 44. The external power supply 44 is, for example, a DC power supply, and constantly applies a negative electric field control voltage (−VE) to the electric field control electrodes 37, 37.
The ground side of the external power supply 44 and the ground side of the high voltage power supply 13 have the same potential.

When a switch (not shown) in the high-voltage power supply 13 is short-circuited, charges are accumulated in the capacitor C2, a voltage is applied to both ends of the saturable reactor L, and the saturable reactor L becomes low impedance after a predetermined time. Thus, the electric charge of the capacitor C2 is transferred to the main discharge capacitor Cp1. When the voltage between both poles of the main discharge capacitor Cp1 reaches a predetermined value, a preliminary discharge 19 occurs between the anode 5A and the internal conductor 26 as shown in FIG. And a main discharge 35 occurs. The preliminary discharge 19 generates ultraviolet light (not shown), and the laser gas in the discharge space 16 is ionized (preliminary ionization) in advance. This prevents the main discharge 35 from becoming an arc discharge, so that the main discharge 35 is uniformly and stably performed over the entire discharge space 16.

During the preliminary discharge 19, the internal conductor 26
Electrons move from the anode to the anode 5A. At this time, electrons having a negative charge are transferred to the left and right electric field control electrodes 37.
Is repelled by the negative electric field control voltage (-VE) applied to the discharge space 16 and is pushed into the discharge space 16. As a result, the region where the preliminary discharge 19 occurs narrows in the left-right direction, so that the range in which the laser gas is pre-ionized also narrows in the left-right direction. Since the pre-ionized range of the laser gas preferentially contributes to the main discharge 35, the range in which the main discharge 35 occurs is narrowed, and expansion of the discharge space 16 in the left-right direction can be suppressed.

Further, also during the main discharge 35, the electrons receive repulsive forces from the left and right electric field control electrodes 37, 37 while flowing from the cathode 5B to the anode 5A, and are pushed into the inside of the discharge space 16 from both left and right sides. Thereby, the main discharge 3
5 is reduced, and expansion of the discharge space 16 in the left-right direction can be suppressed.

As described above, according to the present embodiment,
Electric field control electrodes 37 are provided on both sides of the discharge space 16, and a negative electric field control voltage (-VE) is applied to the electrodes. Thereby, the electrons are pushed into the inside of the discharge space 16, and
The expansion of the discharge space 16 is prevented, and the beam profile is stabilized. In addition, since the expansion of the discharge space 16 is prevented, the discharge from the main electrodes 5A and 5B to the components in the laser chamber 2 other than the main electrodes 5A and 5B (hereinafter, such a discharge with other components instead of between the electrodes). (A discharge that does not contribute to laser oscillation is referred to as a parasitic discharge). Accordingly, the main discharge 35 is stabilized, and the components can be brought close to the main electrodes 5A and 5B, so that the excimer laser device 1 can be downsized.

Further, since the expansion of the discharge space 16 is eliminated, the width of the discharge space 16 and the width of the opening 45 can be made substantially equal. As a result, the ratio of the main discharge 35 that does not contribute to laser oscillation is reduced, and the energy input to the discharge space 16 is efficiently used for laser oscillation, and the energy efficiency of the excimer laser device 1 is improved. Further, even when a high voltage is applied between the main electrodes 5A and 5B, the discharge space 16 does not expand, so that higher-density energy can be applied to the discharge space 16. Thereby, the power of the laser beam 11 can be increased.
In such a case, the discharge space 16 tends to expand as the higher voltage is applied between the main electrodes 5A and 5B. Therefore, the higher the applied high voltage, the higher the electric field control voltage (−V
E) should be increased.

Electrons move from the cathode 5B to the anode 5B.
Since the line moves substantially linearly to A, as shown in FIG. 4, the lines of electric force 47 in the discharge space 16 are parallel to the left-right direction, and the electric field is uniform. As a result, the beam profile of the laser light 11 is adjusted. Further, the main electrodes 5A,
Even if 5B is consumed by the main discharge 35, since the lines of electric force are always parallel, the shape of the discharge space 16 becomes constant, and stable laser oscillation can be performed without fluctuation of the beam profile.

Further, since the electric field control electrode 37 is formed in a metal rod shape, the structure is simple. In addition, because of the thin rod shape, the main electrode 5 can be kept close to the discharge space 16.
It is possible to keep away from A and 5B. Therefore, no parasitic discharge occurs between the main electrodes 5A, 5B and the electric field control electrode 37, and the main discharge 35 is not disturbed. In addition, since a higher electric field control voltage (-VE) can be applied to the electric field control electrode 37, the discharge space 16 can be narrowed more reliably.

Further, as shown in FIG. 5, the main electrodes 5A,
The effect of the electric field control electrode 37 is particularly remarkable when a narrow electrode is used on at least one side of 5B. That is, as described in the section of the prior art, the narrow main electrode 5 is used.
A, 5B, the width of the discharge space 16 is the same as that of the main electrodes 5A,
It can be several times the width of 5B. On the contrary,
By applying an electric field control voltage (-VE) to the electric field control electrode 37, the width of the discharge space 16 can be made substantially equal to the width of the opening 45 of the slit 48. by this,
The width of the laser beam 11 and the width of the discharge space 16 substantially match, the input energy is efficiently used for laser oscillation, and the high-power laser beam 11 can be obtained. By narrowing the beam width in this manner, the oscillation spectrum when the laser light 11 is narrowed becomes narrow. Therefore, when the laser beam 11 is used for processing, the resolution is improved and finer processing is possible.

It has been described that the electric field control voltage (-VE) is always applied to the electric field control electrode 37 while both the preliminary discharge and the main discharge 35 are performed. However, the present invention is not limited to this. Alternatively, the electric field control voltage (-VE) may be applied only during one discharge. Or, external power supply 4
4 is a pulse power source, and when at least one of the preliminary discharge 19 and the main discharge 35 occurs, the electric field control voltage (−
VE) may be applied. In addition, high-voltage power supply 1
Although an external power supply 44 separate from the power supply 3 is provided to apply the electric field control voltage (-VE), the present invention is not limited to this. For example, the internal conductor 26 and the electric field control electrode 37 may be connected, and the electric field control voltage (-VE) may be applied to the electric field control electrode 37 in the form of a pulse during the preliminary discharge 19. Alternatively, the electric field control electrode 37 and the cathode 5B may be connected to each other, and the electric field control voltage (-VE) may be applied in a pulsed manner during the main discharge 35. This eliminates the need for the external power supply 44 and simplifies the wiring. In addition, it becomes possible to apply the electric field control voltage (-VE) only when necessary, so that the electric field control voltage (-VE) can be efficiently used. ) Can be applied. still,
When the electric field control electrode 37 is connected to the internal conductor 26 or the cathode 5B in this manner, an electric field control voltage (−
VE) may be changed to a desired value.

Also, the electric field control voltage (-VE) applied to the electric field control electrodes 37, 37 has been described as being the same on the upstream side and the downstream side of the discharge space 16, but the present invention is not limited to this. . That is, since the discharge space 16 tends to swell more on the downstream side due to the gas flow 36, for example, the electric field control voltage (-VE) applied to the electric field control electrode 37 arranged on the downstream side should be made higher than that on the upstream side. Thereby, the discharge space 16 can be more finely controlled. Further, the value of the applied electric field control voltage (-VE) is preferably determined by observing the state of the main discharge 35 and the beam profile.

The electric field control electrode 37 is connected to the discharge space 16.
Although it was explained that it is provided on both the upstream side and the downstream side of
The invention is not limited to this, and may be arranged, for example, only on the downstream side. As described above, since the discharge space 16 swells greatly downstream, the swelling of the discharge space 16 can be more effectively suppressed by installing the electric field control electrode 37 on the downstream side. Further, the electric field control electrode 37 does not disturb the gas flow 36 in the discharge space 16, and the main discharge 35 is suitably performed. Further, for example, if the electric field control electrode 37 is installed only on the upstream side, parasitic oscillation is unlikely to occur between the electric field control electrode 37 and the main electrodes 5A and 5B.
6, closer to or stronger electric field control voltage (-VE)
And the force for suppressing the discharge space 16 increases.

Hereinafter, the electric field control electrode 37 according to the present embodiment will be described.
3 shows another example of the shape. FIG. 6 is an example of the second shape,
The electric field control electrode 37 has a net shape. Accordingly, the degree of the electric field control electrode 37 obstructing the gas flow 36 is reduced, and, for example, the gas flow rate does not extremely decrease in some regions. It is possible. Furthermore, since the electric field control voltage (-VE) can be uniformly applied to the discharge space 16,
Electrons moving in the discharge space 16 are reliably pushed inward by the main discharge 35, and the discharge space 16 can be narrowed more efficiently. In addition, since the electrons receive the pushing force immediately after leaving the cathode 5B, the electrons move closer to vertical. Therefore, the shape of the discharge space 16 becomes closer to a rectangle, and the beam profile becomes uniform. As another application example, a plurality of thin rod-shaped electric field control electrodes 37 may be arranged vertically in parallel with the main electrodes 5A and 5B.

FIG. 7 shows an example of the third shape, in which the electric field control electrode 37 has a streamlined shape, for example, a water droplet shape. Thereby, the degree of the electric field control electrode 37 obstructing the gas flow 36 is further reduced, and the gas flow velocity does not decrease, so that the oscillation frequency can be increased. FIG. 8 shows an example of the fourth shape, in which the electric field control electrode 37 has a shape in which the periphery of a rod-shaped conductor 39 is covered with a dielectric tube 38.
Is applied with an electric field control voltage (-VE). Thus, the main discharge 35 is stabilized without causing a parasitic discharge between the electric field control electrode 37 and the main electrodes 5A and 5B and other components in the laser chamber 2.

Next, a second embodiment will be described. FIG. 9 shows a detailed view of the electrode according to the present embodiment. In FIG. 9, the external power supply 44 and the high-voltage power supply 13 are both connected to the laser controller 4 that controls the excimer laser device 1, and apply a voltage based on the instruction. In FIG. 9, the illustration of the preliminary ionization electrode is omitted. The laser controller 4 determines the oscillation frequency of the laser light 11 based on, for example, a command from a processing machine (not shown). Then, the laser controller 4 instructs the oscillation frequency to the high-voltage power supply 13, and the high-voltage power supply 13
To oscillate the laser beam 11 at the oscillation frequency.

At this time, the laser controller 4 also outputs a command signal to the external power supply 44, and the electric field control voltage (-VE)
Is set to an appropriate value. For example, if the discharge space 16 moves toward the downstream side, the electric field control voltage (-V) applied to the electric field control electrode 37B disposed on the downstream side.
E) higher than the upstream side. This prevents the movement of the discharge space 16 due to the change in the oscillation frequency, and stabilizes the beam profile and the power of the laser beam 11 while keeping the position of the discharge space 16 constant. Further, the degree of expansion of the discharge space 16 may change according to the oscillation frequency. Therefore, the laser controller 4
The value of the command signal to be output to the external power
A stronger electric field control voltage (-VE) is applied if the oscillation frequency is such that the frequency band 6 greatly spreads, and a weaker electric field control voltage (-VE) is applied if the oscillation frequency is not so wide. Thereby, a discharge space 16 having a constant shape is always obtained, and the beam profile is stabilized.

Another application example is as follows. When the main discharge 35 is continued for a long period of time, the power of the laser beam 11 decreases with the deterioration of the laser gas. Along with this, the laser controller 4 monitors the power of the laser beam 11, and increases the high voltage applied to the main electrodes 5A and 5B when the power decreases. At this time, when the laser gas deteriorates, the discharge space 16 fluctuates and the beam profile fluctuates. In order to prevent this, the degree of deterioration of the laser gas is estimated based on the high voltage, and the electric field control voltage (-VE) applied to the electric field control electrodes 37A and 37B is controlled according to the degree of deterioration. Discharge space 1
It is possible to keep the position and width of 6 constant.

It is known that the main electrodes 5A and 5B are gradually consumed as the main discharge 35 is performed for a long time, and the beam profile fluctuates. To prevent this,
According to the time when the main discharge 35 was performed or the number of pulse discharges,
A command is sent from the laser controller 4 to the external power supply 44,
By controlling the electric field control voltage (-VE) applied to the electric field control electrode 37, the shape of the discharge space 16 can be stabilized. Alternatively, the beam profile oscillated from the excimer laser device 1 may be constantly monitored by a beam profile detector or the like, and the electric field control voltage (-VE) may be controlled based on the fluctuation of the beam profile. In this way, it is possible to suppress the fluctuation of the beam profile and always obtain a stable beam profile.

Although the present invention has been described with respect to an excimer laser, the present invention can be applied to all discharge-excited laser devices. In particular, a fluorine laser can be applied just like an excimer laser.

[Brief description of the drawings]

FIG. 1 is a plan view of an excimer laser device according to a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a charge / discharge circuit diagram of an excimer laser device.

FIG. 4 is an enlarged view near a discharge space.

FIG. 5 is a detailed view of an electrode when a thin main electrode is used.

FIG. 6 shows an example of a second shape of the electric field control electrode.

FIG. 7 shows an example of a third shape of the electric field control electrode.

FIG. 8 shows an example of a fourth shape of the electric field control electrode.

FIG. 9 is a detailed view of an electrode according to a second embodiment.

FIG. 10 is a plan view of an excimer device according to the related art.

FIG. 11 is a detailed view of an electrode.

[Explanation of symbols]

1: excimer laser, 2: laser chamber, 3: heat exchanger, 4: laser controller, 5: main electrode, 7: front window, 8: front mirror, 9: rear window, 11: laser beam, 13: high voltage power supply , 14: once-through fan, 16: discharge space, 18: preliminary ionization electrode, 22: prism, 23: grating, 35: main discharge, 36: gas flow, 37: electric field control electrode, 38: dielectric tube, 3
9: conductor, 44: external power supply, 45: opening, 46: electric field relaxation bar, 48: slit.

Claims (2)

[Claims] 1. A discharge excitation laser device having main electrodes (5A, 5B) arranged opposite to each other with a discharge space (16) therebetween and generating a main discharge (35) between them to excite a laser medium. A discharge excitation laser device equipped with electrodes, wherein an electric field control electrode (37) is arranged on the side of the discharge space (16) substantially in parallel with the main electrodes (5A, 5B) in the longitudinal direction. Laser device. 2. The discharge excitation laser device according to claim 1, wherein the discharge excitation laser device is a pulse laser device that performs pulse oscillation, and an electric field control voltage (-VE) applied to the electric field control electrode (37).
Is changed according to the oscillation condition or state of the laser beam (11).