JP2004179272A - Main discharge electrode for laser device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a main discharge electrode for a laser device which is capable of stable main discharging, and also to provide a method of manufacturing the same. <P>SOLUTION: In the method of manufacturing main discharge electrodes 14 and 15 for a laser device which are formed with a film 71 in at least part of a front surface, the films 71 are formed by flame coating or irradiation of electron beams under a preferrable condition that xenon and/or oxygen is added with no addition of hydrogen. By manufacturing the films 71 by this method for manufacturing the main discharge electrodes 14 and 15, the films 71 are added with xenon and/or oxygen, but not with hydrogen. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a main discharge electrode for a gas laser device and a manufacturing method thereof.
[0002]
[Prior art]
First, the configuration of a general excimer laser device will be described. FIG. 1 is a front sectional view showing a configuration of an excimer laser device 11 according to the first embodiment, and FIG. 2 is a sectional view taken along line AA in FIG.
1 and 2, an excimer laser device 11 includes a metal laser chamber 12 that seals a laser gas containing a halogen gas. Windows 17 and 19 that transmit the laser beam 21 are respectively attached to the front and rear portions of the laser chamber 12.
[0003]
Inside the laser chamber 12, main discharge electrodes 14 and 15 including an anode 14 and a cathode 15 are installed with a predetermined gap. As the material of the main discharge electrodes 14 and 15, a metal such as copper or nickel is used.
An opening 35 is provided in the upper part of the laser chamber 12, and an insulating cathode holder 51 seals the opening 35. The cathode 15 of the main discharge electrodes is fixed to the cathode holder 51 and is electrically connected to the high-voltage HV side of the high-voltage power source 23 by current introduction means (not shown). The laser chamber 12 is electrically connected to the ground GND side of the high-voltage power supply 23.
[0004]
A metal anode holder 50 is installed inside the laser chamber 12 so as to face the cathode holder 51. The anode holder 50 is fixed in a state of being suspended from the laser chamber 12 by a metal plate (not shown). The anode 14 is fixed to the anode holder 50, so that the anode 14 is electrically connected to the ground GND side of the high-voltage power supply 23.
Inside the laser chamber 12, a cross-flow fan 24 that sends laser gas into the discharge space 37 between the main discharge electrodes 14 and 15 and a heat exchanger 13 that cools the laser gas heated by the main discharge are placed at predetermined positions, respectively. is set up.
[0005]
Of the main discharge electrodes 14 and 15, both sides of the anode 14 are constituted by metal rod-like internal conductors 38A and 38A connected to the high voltage side HV and dielectrics 38B and 38B surrounding the outer periphery thereof. The preliminary ionization electrodes 38 and 38 thus fixed are fixed on the anode holder 50.
When a high voltage is applied between the internal conductors 38A, 38A and the anode 14 from the high-voltage power source 23, a corona-shaped preionization discharge occurs between them. As a result, ultraviolet preionization light is generated, and the laser gas in the discharge space 37 is ionized. This is called preionization.
[0006]
Immediately after the preliminary ionization, a high pulsed voltage is applied between the main discharge electrodes 14 and 15 from the high voltage power source 23. Thereby, main discharge occurs, the laser gas is excited, and laser light 21 is generated.
The generated laser beam 21 is amplified by the main discharge while being repeatedly reflected between the front mirror 16 and the rear mirror 18 respectively disposed at the front and rear portions of the laser chamber 12, and a part of the laser beam 21 partially transmits the front mirror 16. Then, the light is emitted forward (to the right in FIG. 1).
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-332786 (FIGS. 1 and 2)
[0008]
[Problems to be solved by the invention]
However, the prior art has the following problems.
That is, during the main discharge, the surface of the main discharge electrodes 14 and 15 facing the discharge space 37 gradually melts or wears due to corrosion caused by heat, impact, and halogen erosion caused by the main discharge. In the following description, the surfaces of the main discharge electrodes 14 and 15 facing the discharge space 37 are called main discharge electrode surfaces.
If hydrogen is mixed in the material of the main discharge electrodes 14 and 15, this hydrogen is liberated during the main discharge and reacts with the laser gas to generate HF and the like to absorb the laser beam 21. The discharge may become unstable.
Therefore, in order to make the output of the laser beam 21 stable and high, it is necessary to stably perform the main discharge by making the materials of the main discharge electrodes 14 and 15 not mixed with hydrogen.
[0009]
However, since the main discharge electrodes 14 and 15 have a length of about several tens of centimeters in the longitudinal direction, the use of a high-purity material that does not contain hydrogen makes the main discharge electrodes 14 and 15 expensive. become. Moreover, it is technically difficult to process such elongated main discharge electrodes 14 and 15 with a high-purity material.
Further, since the main discharge electrodes 14 and 15 are gradually worn out by the main discharge, the life of the main discharge electrodes 14 and 15 is short, and if the expensive main discharge electrodes 14 and 15 are used, the cost of the excimer laser device 11 is further increased. There is a problem.
Moreover, the influence of the purity of the material of the main discharge electrodes 14 and 15 on the main discharge is to a slight depth of the main discharge surface, so even if an expensive material is used for the main discharge electrodes 14 and 15 as a whole, Parts other than the surface of the main discharge electrode do not contribute to stabilization of the main discharge.
[0010]
In order to solve such a problem, a technique is known in which a dielectric film is formed on the surfaces of the main discharge electrodes 14 and 15 to stabilize the discharge (for example, Patent Document 1). However, hydrogen is also generated from the formed dielectric film to generate HF and the like, which may absorb the laser beam 21 and make the main discharge unstable.
[0011]
The present invention has been made paying attention to the above problems, and an object thereof is to provide a main discharge electrode for a laser device capable of stable main discharge and a method for manufacturing the same.
[0012]
[Means, actions and effects for solving the problems]
In order to achieve the above object, according to the present invention,
In the main discharge electrode for a laser device in which a film is formed on at least a part of the surface or a method for manufacturing the same,
The film is formed without adding hydrogen.
Thereby, hydrogen is not liberated from the film, and the output of the laser beam due to this does not decrease.
[0013]
Further, according to the main discharge electrode for a laser device of the present invention or a manufacturing method thereof,
The film is formed by thermal spraying or electron beam irradiation.
Thereby, the film can be firmly fixed to the main discharge electrode.
[0014]
Further, according to the main discharge electrode for a laser device of the present invention or a manufacturing method thereof,
The film is formed by adding at least one of xenon and oxygen.
According to xenon, the output of laser light in the ArF excimer laser device is increased. Also, oxygen increases the output of laser light from the ArF excimer laser device.
[0015]
Also according to the invention,
In a main discharge electrode for a laser device that generates a laser beam by causing a main discharge in a discharge space to excite a laser gas,
The body part,
A metal surface layer made of the same kind of metal having a higher purity than that of the body portion is formed on the surface facing the discharge space.
Thereby, since the surface of the main discharge electrode facing the discharge space has a high purity, the main discharge is stabilized and the generation of impurities is reduced. Moreover, compared with manufacturing all the main discharge electrodes with a metal with high purity, it can manufacture at a low material cost. Moreover, even if the metal surface layer is worn by the main discharge, it can be reused by forming a new metal surface layer. Further, by increasing the purity, the content of internal hydrogen can be reduced, so that generation of HF can be prevented.
[0016]
The main discharge electrode for a laser device of the present invention is
In a main discharge electrode for a laser device that generates a laser beam by causing a main discharge in a discharge space to excite a laser gas,
The body part,
It is formed on the surface facing the discharge space, satisfies at least one of the following conditions: a hardness higher than that of the body part, a high melting point, and a high corrosion resistance against the halogen gas; The metal surface layer which consists of a dissimilar metal with a low density | concentration is provided.
As a result, the surface of the main discharge electrode facing the discharge space becomes more suitable as a material of the main discharge electrode than the body portion, and hydrogen is not liberated from the surface, so that HF or the like is not generated and impurities are generated. The main discharge is stabilized by decreasing. Further, it can be manufactured at a lower cost compared to manufacturing all the main discharge electrodes with the same metal as the metal surface layer. Moreover, even if the metal surface layer is worn by the main discharge, it can be reused by forming a new metal surface layer.
[0017]
The main discharge electrode for a laser device of the present invention is
In a main discharge electrode for a laser device that generates a laser beam by causing a main discharge in a discharge space to excite a laser gas,
The body part,
It is formed on the surface facing the discharge space, satisfies at least one of the following conditions: a hardness higher than that of the body part, a high melting point, and a high corrosion resistance against the halogen gas; An insulating surface layer made of an insulator having a low concentration is provided.
As a result, the surface of the main discharge electrode facing the discharge space becomes more suitable as a material of the main discharge electrode than the body portion, and hydrogen is not liberated from the surface, so that HF or the like is not generated and impurities are generated. The main discharge is stabilized by decreasing. Moreover, even if the insulating surface layer is worn by the main discharge, it can be reused by forming a new insulating surface layer.
[0018]
The main discharge electrode for a laser device of the present invention is
Increase the temperature by using an inert gas that does not contain hydrogen as the working gas,
The surface layer is formed by blowing the working gas together with the material of the surface layer onto the body portion.
Thereby, since the surface layer does not contain hydrogen, hydrogen in the surface layer is rarely released to the discharge space by the main discharge. Therefore, HF is rarely generated, and the output of laser light is unlikely to decrease.
[0019]
The main discharge electrode for a laser device of the present invention is
Heating an inert gas containing at least one of xenon and oxygen as a working gas,
The surface layer is formed by blowing the working gas together with the material of the surface layer onto the body portion.
Thereby, since the surface layer contains xenon and oxygen, the xenon and oxygen in the surface layer are released into the discharge space by the main discharge.
Therefore, according to xenon, the output of the laser beam in the ArF excimer laser device is increased. Also, oxygen increases the output of laser light from the ArF excimer laser device.
[0020]
Further, according to the method for manufacturing a main discharge electrode for a laser device of the present invention,
In the method of manufacturing a main discharge electrode for a laser device that generates a laser beam by causing a main discharge in a discharge space to excite a laser gas,
Increase the temperature by using an inert gas that does not contain hydrogen as the working gas,
A surface layer facing the discharge space is formed by blowing the working gas together with the material of the surface layer onto the body portion.
As a result, the surface layer is firmly fixed to the body portion, and is hardly peeled off even by main discharge. In addition, since the surface layer does not contain hydrogen, hydrogen in the surface layer is liberated by the main discharge and HF is hardly generated, and the output of laser light is unlikely to decrease.
[0021]
Further, according to the method for manufacturing a main discharge electrode for a laser device of the present invention,
In the method of manufacturing a main discharge electrode for a laser device that generates a laser beam by causing a main discharge in a discharge space to excite a laser gas,
Heating an inert gas containing at least one of xenon, oxygen, and hydrogen at a concentration that stabilizes the main discharge as a working gas,
A surface layer facing the discharge space is formed by blowing the working gas together with the material of the surface layer onto the body portion.
As a result, the surface layer is firmly fixed to the body portion, and is hardly peeled off even by main discharge. Moreover, since the surface layer contains at least one of xenon and oxygen, these gases are released into the discharge space by the main discharge. As a result, according to xenon, the output of the laser light of the ArF excimer laser device increases. Also, oxygen increases the output of laser light from the ArF excimer laser device.
[0022]
Further, according to the method for manufacturing a main discharge electrode for a laser device of the present invention,
Under atmosphere of atmosphere gas not containing hydrogen,
The surface layer facing the discharge space is formed by irradiating the surface layer material and body part with an electron beam.
As a result, the thermal stress applied to the body part is small and distortion or the like hardly occurs. In addition, since the surface layer does not contain hydrogen, hydrogen in the surface layer is liberated by the main discharge and HF is hardly generated, and the output of laser light is unlikely to decrease.
[0023]
Further, according to the method for manufacturing a main discharge electrode for a laser device of the present invention,
Under an atmosphere of an atmosphere gas containing at least one of xenon and oxygen,
The surface layer facing the discharge space is formed by irradiating the surface layer material and body part with an electron beam.
As a result, the thermal stress applied to the body part is small and distortion or the like hardly occurs. Moreover, since the surface layer contains at least one of xenon and oxygen, these gases are released into the discharge space by the main discharge. As a result, according to xenon, the output of the laser light of the ArF excimer laser device increases. Also, oxygen increases the output of laser light from the ArF excimer laser device.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
First, the first embodiment will be described. The schematic configuration of the excimer laser device 11 is the same as that shown in FIG.
FIG. 3 is a cross-sectional view of the main discharge electrodes 14 and 15 and the discharge space 37 therebetween, as viewed from the longitudinal direction, and FIG. 4 is a cross-sectional view of the anode 14 taken along the line BB. Hereinafter, the anode 14 is represented as the main discharge electrode, but the cathode 15 is the same.
[0025]
As shown in FIGS. 3 and 4, the main discharge electrodes 14 and 15 include a body portion 70 made of metal and a thin insulating surface layer 71 made of an insulator formed on the surface facing the discharge space 37. I have. The thickness of the insulating surface layer 71 is, for example, about 0.1 to 1 mm.
As a material of the body part 70, metals such as aluminum, nickel, brass, copper, iron, stainless steel, and cobalt are used.
[0026]
Examples of the material of the insulator forming the insulating surface layer 71 include oxides such as alumina (aluminum oxide) and zirconia (zirconium oxide), nitrides such as aluminum nitride, sodium chloride, aluminum chloride, and potassium chloride. And the like are preferred.
Furthermore, fluorides such as copper fluoride, calcium fluoride, magnesium fluoride, aluminum fluoride, sodium fluoride, or potassium fluoride may be used.
[0027]
At this time, the insulator needs to have corrosion resistance to the halogen gas in the laser gas. For example, when the laser gas contains fluorine, an oxide, nitride, or fluoride is used as the insulator. In addition, when chlorine is contained in the laser gas, oxide, nitride, or chloride is used.
[0028]
In addition, the insulator satisfies at least one of the following conditions: higher hardness, higher melting point, and higher corrosion resistance to halogen gas than the metal material used for the body part 70. Is desirable. This is to prevent the main discharge electrodes 14 and 15 from being damaged by the main discharge impact or heat.
Furthermore, it is desirable for the insulator to have a lower hydrogen concentration inside than the metal material used for the body portion 70, thereby preventing the generation of HF based on the liberation of hydrogen.
[0029]
For example, when the body portion 70 is formed of copper, alumina or the like is suitable as the insulator. That is, the hardness of alumina is higher than that of copper, and its melting point (about 2000 degrees) is higher than that of copper (about 1080 degrees). Alternatively, when the body portion 70 is copper, the insulator may be aluminum nitride.
[0030]
Next, a method for forming such an insulating surface layer 71 will be described in detail. In the present invention, the insulating surface layer 71 is formed by thermal spraying.
In FIG. 5, the block diagram of the thermal spraying apparatus 40 based on 1st Embodiment is shown. In FIG. 5, the thermal spraying device 40 includes a thermal spraying chamber 41 in which the anode 14 is installed.
[0031]
The thermal spraying chamber 41 includes a thermal spraying torch 42 that blows an insulator onto the main discharge electrodes 14 and 15. FIG. 6 is an explanatory view of the plasma jet type thermal spraying torch 42. The thermal spray torch 42 applies a high voltage between the cathode 43 and the thermal spray nozzle 44 that is an anode to generate arc discharge. When the working gas 45 is blown spirally from the rear, the working gas 45 is ionized to be in a plasma state.
[0032]
When this ionized plasma returns to its original state, it releases a large amount of heat and expands to become a jet jet 52 of thermal plasma of several tens of thousands of degrees. By introducing an insulator 49, which is the material of the insulating surface layer 71, into this thermal plasma, the molten insulator is sprayed onto the main discharge electrodes 14 and 15, so that the surface of the body portion 70 is melted and integrated to provide insulation. A surface layer 71 is formed.
[0033]
After the insulating surface layer 71 is formed by thermal spraying, precision processing such as polishing is performed to adjust the shape of the insulating surface layer 71. Thereby, the main discharge electrodes 14 and 15 in which the insulating surface layer 71 is formed in the portion facing the discharge space 37 are formed.
[0034]
In the present invention, such plasma spraying is performed under a low pressure so that impurities are not mixed in the insulating surface layer 71. Such a thermal spraying method is called, for example, a VPS (Vacuum Plasma Spraying) thermal spraying method.
[0035]
A vacuum pump 48 is connected to the thermal spraying chamber 41, and the inside can be evacuated to, for example, about several mm Torr.
That is, the inside of the thermal spraying chamber 41 is evacuated to several mm Torr by the vacuum pump 48 and sprayed while flowing a working gas 45 containing an inert gas (hereinafter represented by argon) such as helium, neon, argon, or krypton. To start. In FIG. 5, 46 is an argon gas cylinder.
At this time, evacuation is continued by the vacuum pump 48, and the pressure in the thermal spraying chamber 41 is, for example, several tens of Torr.
[0036]
In a general VPS thermal spraying method, hydrogen is added to argon by several% to several tens% as working gas 45 in order to generate plasma stably. However, in this embodiment, by not adding hydrogen, the insulating surface layer 71 of the main discharge electrodes 14 and 15 is prevented from containing hydrogen.
As a result, hydrogen is less likely to be generated from the main discharge electrodes 14 and 15 during the main discharge, so that the output of the laser beam 21 is less likely to decrease due to the generation of HF.
[0037]
As described above, according to the first embodiment, the insulating surface layer 71 of an insulator is formed on the surface of the metal body portion 70 of the main discharge electrodes 14 and 15 facing the discharge space 37. As a result, impurities are less likely to be generated from the main discharge electrodes 14 and 15 during the main discharge, so that impurities are not mixed into the discharge space 37 and the output of the laser beam 21 is not lowered.
[0038]
Further, by forming the insulating surface layer 71 of an insulator, the body portion 70 is less likely to be damaged by the heat or impact of the main discharge. Further, since the main discharge is performed through the insulating surface layer 71, a stable main discharge with a small impact can be performed, and damage to the insulating surface layer 71 is small.
[0039]
When the main discharge is performed between the metal main discharge electrodes 14 and 15, the shape of the main discharge electrode surface greatly affects the stability of the main discharge. On the other hand, by performing the main discharge through the insulator, the main discharge is less likely to become unstable even if the insulating surface layer 71 is somewhat damaged.
[0040]
For example, even when the insulating surface layer 71 is damaged or worn, the body portion 70 remains in an almost intact shape. Therefore, the main discharge electrodes 14 and 15 are formed by forming the insulating surface layer 71 again. Can be used over a long period of time.
[0041]
Furthermore, the insulating surface layer 71 is formed by plasma spraying. In plasma spraying, since the thermal spray material is firmly fixed to the body portion 70, the insulating surface layer 71 is hardly peeled off from the body portion 70 by the main discharge, and the main discharge is less likely to become unstable.
[0042]
Further, plasma spraying is performed in a low pressure atmosphere of a predetermined working gas 45 by using the VPS spraying method. Thereby, impurities such as organic substances are rarely mixed into the insulating surface layer 71 at the time of thermal spraying, and impurities are hardly scattered into the discharge space 37 by the main discharge.
[0043]
Furthermore, since an inert gas such as argon is used as the working gas 45, a chemical reaction hardly occurs between the working gas 45 and the body portion 70 or the insulator. In addition, since hydrogen is removed from the working gas 45, the generation of HF is unlikely to occur during the main discharge, and the output of the laser beam 21 due to HF is unlikely to decrease.
[0044]
FIG. 7 is a graph showing a comparison of the output characteristics of the laser beam 21 by the main discharge electrodes 14 and 15 on which the insulating surface layer 71 is formed by plasma spraying according to the present embodiment. In FIG. 7, the horizontal axis is the input energy of the main discharge, and the vertical axis is the output energy of the laser beam 21.
[0045]
Further, in FIG. 7, when the anode 14 and the cathode 15 in which H is plasma sprayed with the working gas 45 containing hydrogen are used, the anode 14 and the cathode in which AC is plasma sprayed with the working gas 45 not containing hydrogen. 15 is used. C is an output characteristic when only the anode 14 does not contain hydrogen and the cathode 15 contains hydrogen.
[0046]
As shown in FIG. 7, when the plasma spraying of the anode 14 and the cathode 15 is performed with the working gas 45 not containing hydrogen (AC), the output is the highest. When the plasma spraying of the anode 14 and the cathode 15 is performed with the working gas 45 containing hydrogen (H), the output is the lowest.
Thus, by performing thermal spraying so that the working gas 45 does not contain hydrogen, the output of the laser beam 21 can be increased.
[0047]
Next, a second embodiment will be described.
In FIG. 8, the block diagram of the thermal spraying apparatus 40 based on 2nd Embodiment is shown. In addition to an argon cylinder 46, an additive gas cylinder 47 is connected to the thermal spray chamber 41.
That is, in the second embodiment, an additive gas is added to the inert gas as the working gas 45.
[0048]
First, the case where oxygen is added as an additive gas will be described.
FIG. 9 shows the output characteristics of the laser beam 21 when oxygen is added to the laser gas. In FIG. 9, the horizontal axis represents the oxygen addition concentration (ppm), and the vertical axis represents the output energy of the laser beam 21. As shown in FIG. 9, when oxygen is mixed in the laser gas by about 5 to 50 ppm, the output energy of the laser beam 21 is increased. More desirably, about 5 to 30 ppm is mixed.
[0049]
By adding oxygen to the working gas 45 in addition to an inert gas such as argon during plasma spraying, the insulating surface layer 71 contains a small amount of oxygen. During the main discharge, this oxygen is liberated from the insulating surface layer 71 to the discharge space 37. As a result, the same effect as when oxygen is added to the laser gas is obtained, and the output of the laser beam 21 is increased.
The amount of oxygen added to the working gas 45 may be added so that the oxygen concentration in the discharge space 37 is substantially the same as when about 5 to 30 ppm of oxygen is mixed in the laser gas.
[0050]
Next, a case where xenon is added as an additive gas to the working gas 45 will be described.
FIG. 10 shows the output characteristics of the laser light 21 when xenon is added to the laser gas in the ArF excimer laser apparatus. In FIG. 10, the horizontal axis represents the xenon addition concentration (ppm), and the vertical axis represents the output energy of the laser beam 21. As shown in FIG. 10, when xenon is mixed in the laser gas by about 5 to 20 ppm, the output energy of the laser beam 21 is increased.
[0051]
That is, when manufacturing the main discharge electrodes 14 and 15 for the ArF excimer laser device, xenon is mixed into the working gas 45 in addition to an inert gas such as argon. The amount of xenon added to the working gas 45 may be added so that the xenon concentration in the discharge space 37 is substantially the same as when about 5 to 20 ppm of xenon is mixed in the laser gas.
[0052]
As a result, a small amount of xenon is contained in the insulating surface layer 71, and this xenon is released from the insulating surface layer 71 into the discharge space 37 during main discharge. As a result, an effect similar to that obtained by adding xenon to the laser gas is obtained, and the output of the laser light 21 of the ArF excimer laser device is increased.
However, the output of the laser light 21 is increased by xenon in this way only in the case of an ArF excimer laser device using argon, fluorine, and an inert gas such as neon or helium as the laser gas.
[0053]
In the above description, only the case where the surface layer is formed of an insulator has been described. However, the present invention is not limited to this, and the surface layer may be a metal surface layer formed of metal. This will be described in detail below.
That is, when the main discharge electrodes 14 and 15 are formed entirely of metal, the material of the main discharge electrodes 14 and 15 is preferably as high as possible. This is because the generation of impurities from the main discharge electrodes 14 and 15 is suppressed and the discharge becomes stable. However, if the main discharge electrodes 14 and 15 including the body portion 70 are entirely made of a metal having high purity, it becomes expensive and the manufacturing difficulty is high.
[0054]
Therefore, the main discharge electrodes 14 and 15 can be easily manufactured by forming only the surface of the main discharge electrode with a metal having the same kind as the body portion 70 and high purity. As a result, the main discharge is stabilized and impurities are not easily generated, so that a decrease in the output of the laser light 21 is reduced.
If the surface layer is made of the same kind of metal having a low internal hydrogen concentration, generation of HF can be prevented.
[0055]
In addition, the metal used for the body portion 70 has a higher hardness, a higher melting point, and a higher resistance to halogen gas, satisfying at least one of the conditions, and the internal hydrogen concentration is high. You may comprise a surface layer with a low dissimilar metal. Thereby, the tolerance with respect to the main discharge of the main discharge electrodes 14 and 15 can be improved and the life can be extended. Further, since the hydrogen content is small, hydrogen is not liberated and HF is hardly generated.
[0056]
That is, as described in the first and second embodiments, an inert gas such as argon is used as the working gas 45, and metal is supplied in the same manner as the insulator 49 shown in FIG. Thermal spray. At this time, by removing hydrogen from the working gas 45, adding oxygen as an additive gas to the working gas 45, or adding xenon in the case of the main discharge electrodes 14 and 15 for the ArF excimer laser device, A decrease in the output of the laser beam 21 can be prevented.
[0057]
Next, a third embodiment will be described.
In FIG. 11, the block diagram of the electron beam irradiation apparatus 60 which concerns on 3rd Embodiment is shown. In FIG. 11, the electron beam irradiation device 60 includes an electron beam chamber 61 in which main discharge electrodes 14 and 15 are installed, and an electron beam nozzle 62 that irradiates an electron beam 63.
[0058]
At the time of manufacture, the inside of the electron beam chamber 61 is evacuated to a high vacuum by the vacuum pump 48, and a very small amount of atmospheric gas 65 is sent into the interior using the mass flow controller 64. The atmospheric gas 65 is mainly made of an inert gas such as argon, and prevents the generation of HF by preventing hydrogen from being contained in the same manner as described in the first embodiment.
[0059]
Further, only in the case of an ArF excimer laser device, the atmosphere gas 65 may contain either oxygen or xenon as an additive gas. In FIG. 11, it is drawn so as to include the additive gas.
Note that the pressure of the atmospheric gas 65 needs to be set to a level that does not hinder the progress of the electron beam 63.
[0060]
Main discharge electrodes 14 and 15 are installed inside the electron beam chamber 61. A plurality of small holes 74 having a depth of about 0.005 mm to 1.5 mm are provided on the surface of the body portion 70 of the main discharge electrodes 14, 15. A high metal 73 is embedded. Alternatively, the metal 73 is different from the body portion 70, satisfies at least one of the conditions that the hardness is high, the melting point is high, and the corrosion resistance against the halogen gas is high, and the internal hydrogen concentration The surface layer may be composed of a dissimilar metal having a low value.
When the surface of the main discharge electrode is irradiated with the electron beam 63, the surface is heated locally, and the embedded metal 73 and the surface of the body part 70 are melted and mixed.
[0061]
When the main discharge electrodes 14 and 15 are cooled, a metal surface layer 72 is formed on the surface layer of the body portion 70 as shown in FIG. At this time, since the inside of the electron beam chamber 61 is filled with a small amount of the atmospheric gas 65 as described above, the atmospheric gas 65 is taken into the metal surface layer 72 during melting.
And when atmospheric gas 65 does not contain hydrogen, the production | generation of HF is prevented. When the atmosphere gas 65 contains an additive gas, the additive gas is released to the discharge space 37 during the main discharge, increasing the output of the laser beam 21 or stabilizing the main discharge.
[0062]
Alternatively, a metal 73 may be placed on the surface of the body part 70 and the electron beam 63 may be irradiated. As a result, the surface of the body portion 70 and the metal 73 are melted and mixed, and the metal surface layer 72 is formed.
[0063]
As described above, according to the third embodiment, the main discharge electrodes 14 and 15 are heated by the electron beam 63 to form the metal surface layer 72. Thereby, only the surface of the body part 70 is locally heated, so that it is difficult for thermal stress to remain in the body part 70.
[0064]
Further, when an electron gas 63 is irradiated, an inert gas such as argon is used as the atmosphere gas 65, and hydrogen is not included therein, thereby preventing generation of hydrogen from the main discharge electrodes 14 and 15, The output reduction of the laser beam 21 is prevented.
Further, by adding oxygen to the atmosphere gas 65, the output of the laser light 21 is increased. Further, in the main discharge electrodes 14 and 15 for the ArF excimer laser device, the output of the laser light 21 is increased by including xenon in the atmospheric gas 65.
[0065]
The description of each of the above embodiments can be applied only to the ArF excimer laser device with respect to the addition of xenon. Further, with respect to the addition of other gases and the manufacturing method using an inert gas not containing hydrogen, any excimer laser device, fluorine molecular laser device, or the like can be similarly applied.
Further, the example in which the front mirror 16 and the rear mirror 18 are provided as the resonator of the excimer laser device has been shown. However, for example, instead of the rear mirror 18, a narrow-band optical such as a grating that narrows the wavelength of the laser light 21. An element may be used.
In the above description, the main discharge electrodes 14 and 15 have been described in exactly the same manner, but a surface layer may be formed on only one side, or different types of surface layers may be formed.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a configuration of a general excimer laser device.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a cross-sectional view of the main discharge electrode according to the first embodiment as viewed from the longitudinal direction.
4 is a cross-sectional view taken along the line BB in FIG. 3;
FIG. 5 is a configuration diagram of a thermal spraying apparatus according to the first embodiment.
FIG. 6 is an explanatory diagram of a thermal spray torch according to the first embodiment.
FIG. 7 is a graph showing comparison of output characteristics of laser light.
FIG. 8 is a configuration diagram of a thermal spraying apparatus according to a second embodiment.
FIG. 9 is a graph showing output characteristics of laser light when oxygen is added to the laser gas.
FIG. 10 is a graph showing output characteristics of laser light when xenon is added to the laser gas.
FIG. 11 is a configuration diagram of an electron beam irradiation apparatus according to a third embodiment.
FIG. 12 is an enlarged view of a main discharge electrode.
[Explanation of symbols]
11: excimer laser device, 12: laser chamber, 13: heat exchanger, 14: main discharge electrode (anode), 15: main discharge electrode (cathode), 16: front mirror, 17: front window, 18: rear mirror, 19 : Rear window, 21: laser light, 23: high-voltage power supply, 24: cross-flow fan, 35: opening, 37: discharge space, 38: preionization, 40: spraying device, 41: spraying chamber, 42: spraying torch, 43 : Cathode, 44: spray nozzle, 45: working gas, 46: argon cylinder, 47: additive gas cylinder, 48: vacuum pump, 49: insulator, 50: anode holder, 51: cathode holder, 52: jet jet, 60: Electron beam irradiation device, 61: electron beam chamber, 62: electron beam nozzle, 63: electron beam, 64: mass flow controller La, 65: atmospheric gas, 70: body portion, 71: insulating surface layer, 72: metal surface layer, 73: metal, 74: Small holes.

Claims (6)

In the method of manufacturing a main discharge electrode for a laser device in which a film (71, 72) is formed on at least a part of the surface,
The method of manufacturing a main discharge electrode for a laser device, wherein the films (71, 72) are formed without adding hydrogen. In the main discharge electrode for a laser device in which a film (71, 72) is formed on at least a part of the surface,
A main discharge electrode for a laser device, wherein hydrogen is not added to the films (71, 72). 2. The method of manufacturing a main discharge electrode for a laser device according to claim 1, wherein the film (71, 72) is formed by thermal spraying or electron beam irradiation. The main discharge electrode for a laser device according to claim 2, wherein the film (71, 72) is formed by thermal spraying or electron beam irradiation. The method of manufacturing a main discharge electrode for a laser device according to claim 1, wherein the film (71, 72) is formed by adding at least one of xenon and oxygen. Method. The main discharge electrode for a laser device according to claim 2, wherein the film (71, 72) is formed by adding at least one of xenon and oxygen.

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