JP2006049422A - Gas laser oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the contamination of a window constituting a gas laser oscillator. <P>SOLUTION: A container structure constituted of a Bessel 1, a gate valve 5, and a housing 6 defines: a main cavity S<SB>1</SB>in which a laser medium gas and discharge electrodes 2a and 2b which excite the gas are housed; and an intermediate cavity S<SB>2</SB>one end of which is opened in the internal wall surface of the main cavity S<SB>1</SB>in the propagating direction of laser light L as a first opening 21 and the other end of which is constituted as a second opening 22 communicated with the external space. The window 61 closes the second opening 22. An inclined member 25 provided around the first opening 21 on the internal wall surface of the main cavity S<SB>1</SB>has a slope 251 inclined, so that the slope 251 is raised to the main cavity S<SB>1</SB>side from a virtual plane orthogonally crossing the propagating direction of the laser light L as approaching the center of the first opening 21 along the virtual plane. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas laser oscillation device, and more particularly to a gas laser oscillation device provided with a plate-like body such as a window.

  A gas laser oscillation device includes a container that contains a laser medium gas and a pair of discharge electrodes that excite the laser medium gas by pulse discharge, and a resonator that confines light generated by excitation of the laser medium gas in the container. Prepare. The resonator is constituted by a partial reflection mirror and a total reflection mirror arranged so as to face the propagation direction of the laser light. For example, in an external mirror type gas laser oscillation device, a partial reflection mirror and a total reflection mirror are arranged outside the container. In this case, in order to extract the light generated inside the container to the outside of the container, a part of the side wall of the container is constituted by a plate-like window transparent to the light.

  When pulse discharge is generated between the discharge electrodes, the surface of the discharge electrode is sputtered to generate metal powder as impurities. For example, when the laser medium gas contains a halogen, the halogen is highly reactive, so that a halogen compound as an impurity is easily generated in the container. For this reason, when the gas laser oscillation device is operated for a long period of time, these impurities may adhere to the inner surface of the window, thereby reducing the light transmittance of the window. As a result, the intensity of the laser beam emitted from the gas laser oscillation device is reduced. Further, impurities adhering to the window absorb laser light, and the temperature of the window is rapidly increased. As a result, the window may be damaged by thermal stress.

  Therefore, there is known a technique in which a purified gas (hereinafter referred to as a purified gas) that passes through a gas purification device is supplied toward the inner surface of the window during operation of the gas laser oscillation device (Patent Document). 1). According to this technique, the purified gas supplied toward the inner surface of the window prevents the laser medium gas containing impurities from staying in the vicinity of the inner surface of the window, so that contamination of the window can be prevented. .

JP 2000-340863 A

  Due to the limited flow rate of the purified gas supplied to the inner surface of the window, the window may still be contaminated. In particular, when a gas flow of a laser medium gas that flows in the width direction of the discharge electrode is formed inside the container, impurities carried by the gas flow may adhere to the inner surface of the window. Further, when a pulse discharge is generated between the discharge electrodes, a shock wave is generated in the container, and impurities carried by the shock wave may adhere to the inner surface of the window.

  In addition, it is thought that contamination of a window can be suppressed, so that the flow volume of the purification gas sprayed on the inner surface of a window is increased. However, in order to increase the flow rate of the purified gas, the pump and the gas purification device for supplying the purified gas into the container will be increased in size, resulting in difficulty in terms of cost and space. .

  The above-described problem can also occur in the internal mirror type gas laser oscillation device in which the partial reflection mirror and the total reflection mirror each constitute a part of the side wall of the container. That is, if impurities adhere to the inner surfaces of the partial reflection mirror and the total reflection mirror, problems such as a reduction in the output of the laser beam and a breakage of the partial reflection mirror and the total reflection mirror occur.

  An object of the present invention is to provide a gas laser oscillation apparatus capable of preventing contamination of a plate-like body such as a window, a partial reflection mirror, or a total reflection mirror.

  According to an aspect of the present invention, a main cavity in which a laser medium gas and an exciter for exciting the laser medium gas are accommodated, and a laser medium gas in the main cavity are generated by being excited by the exciter. An intermediate cavity through which the laser beam passes, with respect to the propagation direction of the laser beam, one end is a first opening that opens on the inner wall surface of the main cavity, and the other end is a second that communicates with an external space. A container structure that defines an intermediate cavity that is configured as an opening, a plate-like body that is held by the container structure and closes the second opening, and the first wall on the inner wall surface of the main cavity. An inclination that is provided around the opening and is inclined so as to be lifted from the virtual plane toward the main cavity along the virtual plane orthogonal to the propagation direction of the laser light as the center of the first opening is approached. Have face That gas laser oscillator apparatus provided with an inclined member.

  Even if the gas flow toward the first opening is formed along the inner wall surface of the main cavity, the direction of the gas flow is changed to the direction away from the first opening by the inclined surface of the inclined member. The This prevents impurities carried by the gas stream from entering the intermediate cavity. As a result, contamination of the plate-like body can be prevented.

FIG. 1A shows a cross-sectional view of an excimer laser oscillation apparatus according to an embodiment. FIG. 1A is a cross-sectional view perpendicular to the optical axis of laser light emitted from this excimer laser oscillation device. Vessel 1 defines a main cavity S ₁ to the discharge electrodes 2a and 2b to excite the laser medium gas as the laser medium gas is accommodated. Here, the laser medium gas refers to a gas that generates light and serves as a medium for amplifying the generated light, and includes a rare gas such as krypton and a halogen such as fluorine.

The discharge electrodes 2a and 2b are arranged in a state of facing each other with a space therebetween. Although not shown, the main cavity S _1, the pulse voltage application circuit for applying repeatedly a pulse voltage between the discharge electrodes 2a and 2b are also arranged. When the pulse voltage application circuit applies a pulse voltage between the discharge electrodes 2a and 2b, glow discharge is generated between the discharge electrodes 2a and 2b. By glow discharge generated, the laser medium gas in the main cavity S ₁ is excited.

When glow discharge is caused between the discharge electrodes 2a and 2b, the surfaces of the discharge electrodes 2a and 2b are sputtered to generate particulate impurities such as metal powder. Further, since the laser medium gas comprises a highly reactive halogen, halogen compound gas is a gaseous impurity in the main cavity S ₁ is generated easily. For this reason, when the laser oscillation device is operated for a long period of time, the laser medium gas in the main cavity S ₁ contains impurities.

Consider an XYZ orthogonal coordinate system in which the direction parallel to the width direction of the discharge electrodes 2a and 2b is the X direction and the direction parallel to the opposing direction of the discharge electrodes 2a and 2b is the Y direction. One end of the gas flow path 3 is connected to one end of the vessel 1 in the X direction, and the other end of the gas flow path 3 is connected to the other end of the vessel 1 in the X direction. A blower 4 is disposed in the gas flow path 3. A blower 4 disposed outside the vessel 1 circulates the laser medium gas in a closed gas circulation path constituted by the gas flow path 3 and the vessel 1. Thus, in the main cavity S within _1, the gas flow F of the laser medium gas flowing in the X direction is formed.

FIG. 1B shows a side view of the excimer laser oscillation device viewed from the X direction. In FIG. 1B, the gas flow path 3 and the blower 4 are not shown for simplicity. A housing 6 is connected to one end of the vessel 1 in the Z direction (the left end in FIG. 1) via a gate valve 5, and a first mirror holder 7 is connected to the housing 6. The housing 6 holds a window 61 as a plate-like body. The window 61 is made of a material that transmits ultraviolet light, such as magnesium fluoride or synthetic quartz (SiO ₂ ). The first mirror holder 7 holds a partial reflection mirror 71.

  On the other hand, similarly, the housing 6 is connected to the other end portion in the Z direction of the vessel 1 (the right end portion in FIG. 1) via the gate valve 5, and the second mirror holder 8 is connected to the housing 6. Has been. The housing 6 provided at the other end in the Z direction of the vessel 1 also holds the window 61. The second mirror holder 8 holds a total reflection mirror 81. The total reflection mirror 81 and the partial reflection mirror 71 constitute an optical resonator.

By laser medium gas in the main cavity S ₁ is excited by the glow discharge between the discharge electrodes 2a and 2b, the laser beam L is generated having a wavelength in the ultraviolet range. The generated laser beam L passes through the windows 61 arranged at both ends in the Z direction, and reciprocates between the partial reflection mirror 71 and the total reflection mirror 81. In the reciprocation process, the laser beam L is amplified, and a part of the amplified laser beam L passes through the partial reflection mirror 71 and is emitted to the outside.

A gas processor 10, a filter 11, and a pump 12 are connected to the vessel 1 through a gas line 13. The pump 12 circulates the laser medium gas in the laser medium gas circulation path constituted by the gas processor 10, the filter 11, the gas line 13 and the vessel 1. Gas processor 10 to capture the gaseous impurities contained in the laser medium gas taken out of the main cavity S within _1. The filter 11 captures particulate impurities contained in the laser medium gas that has passed through the gas processor 10.

The laser medium gas is purified by the gas processor 10 and the filter 11, and the purified laser medium gas passes through the pump 6 and the gas line 13 through the housing 6 provided at both ends in the Z direction of the vessel 1. It is returned into the cavity _{S 1.} Since the structure of both ends in the Z direction of the vessel 1 is substantially the same, the structure of one end in the Z direction of the vessel 1 will be described in detail below.

FIG. 2 shows an enlarged cross-sectional view of one end of the vessel 1 in the Z direction. FIG. 2 is a cross-sectional view parallel to the XZ plane. In FIG. 2, the illustration of the first mirror holder 7 shown in FIG. A through portion 1 a is formed on the side wall of the vessel 1. Penetrating portion 1a is formed at a position where the laser medium gas in the main cavity S ₁ intersects the optical axis of the laser beam L generated by being discharge excitation.

The housing 6 has a hollow cylindrical shape, and is connected to the vessel 1 via the gate valve 5 at a position corresponding to the through portion 1a so that the internal space thereof is connected to the through portion 1a. Thus, the housing 6, together with the vessel 1 defines a constituted intermediate cavity S ₂ by its own internal space and penetrating portion 1a.

Intermediate cavity S ₂ extends in the propagation direction of the laser beam L, a first opening 21 which is opened at one end thereof to the inner wall surface of the main cavity S _1, and the other end to the outside of the space It is configured as a second opening 22 that communicates. The intermediate cavity S ₂ is formed in a cylindrical shape, the shape of the first and second openings 21 and 22 are circular when viewed from both the Z direction.

Window 61, the second opening 22 of the intermediate cavity S ₂ so as to close hermetically and is attached to the housing 6 through the O-ring. Window 61 has one major surface is opposed (hereinafter referred to as the inner surface.) The intermediate cavity S _2, it is attached to the housing 6 in a state in which the other major surface is opposed to the external space.

Gas supply ports 23 a and 23 b are provided in the housing 6. Gas supply port 23a and 23b is connected to the gas line 13 in FIG. 1 (b), a laser medium gas purified by the gas processor 10 and the filter 11 of FIG. 1 (b), the intermediate cavity S in ₂ Supply. Gas supply port 23a and 23b, the housing 6 with respect to the propagation direction of the laser beam L, from the position of the end of the window 61 toward supplies laser medium gas purified to the intermediate cavity S _2. For this reason, the inner surface of the window 61 can be exposed to the atmosphere of the purified laser medium gas.

Intermediate member 24a, 24b, and 24c are provided in the intermediate cavity _{S 2.} The arrangement positions of the intermediate members 24 a to 24 c are between the gas supply ports 23 a and 23 b and the first opening 21 in the propagation direction of the laser light L. Specifically, the intermediate members 24a to 24c are provided on the inner peripheral surface of the penetrating portion 1a. The intermediate members 24a to 24c protrude from the inner peripheral surface of the penetrating portion 1a toward the optical axis of the laser beam L. Specifically, each of the intermediate members 24a to 24c is configured by a rotating body whose cross section parallel to the rotational symmetry axis has a C-shape, and these three intermediate members 24a to 24c are each rotationally symmetric. With the axes aligned with the optical axis of the laser light L, they are discretely arranged in the Z direction.

Each of the intermediate members 24a-24c, the surface of the window 61 side (hereinafter, first. That surface) 241, toward the optical axis of the laser beam L from the inner circumferential surface of the through portion 1a, the main cavity _{S 1} Inclined to approach. Further, each of the intermediate members 24a-24c, the main cavity _{S 1} side of the surface (hereinafter, referred to as a second surface.) 242 also toward the optical axis of the laser beam L from the inner circumferential surface of the through portion 1a, the main It is inclined so as to approach the cavity S _1.

Tilting member 25 is provided around the first opening 21 in the inner wall surface of the main cavity S _1. The inclined member 25 has an inclined surface 251 that is inclined such that the height from the inner wall surface of the main cavity S ₁ increases as the center of the first opening 21 is approached. The inclined surface 251 protrudes closer to the center of the first opening 21 than the edge of the first opening 21. The inclined member 25 is constituted by a rotating body arranged with its rotational symmetry axis coincident with the optical axis of the laser beam L, and the inclined surface 251 surrounds the periphery of the first opening 21 over the entire circumference. Is arranged.

  The distance between the inclined member 25 and the discharge electrode 2a (see FIG. 1) and 2b is an arc between the inclined member 25 and the discharge electrode 2a or 2b when a pulse voltage is applied between the discharge electrodes 2a and 2b. Designed to prevent discharge. Further, from the viewpoint of preventing the occurrence of arc discharge, the end portions of the inclined member 25 on the discharge electrodes 2a and 2b side are not formed into sharp and sharp shapes but are formed into smoothly curved shapes. Further, as the material of the inclined member 25, an insulator such as ceramics is selected.

First and second rectifier plate 26a and 26b are provided in the main cavity _{S 1.} First rectifying plate 26a is provided in the X-direction end portion of the main cavity S _1, second rectifying plate 26b is provided on the X direction end portion. These first and second rectifying plates 26a and 26b exhibit a function of preventing the laser medium gas circulated by the blower 4 in FIG. 1A from forming a turbulent flow.

FIG. 3 is an enlarged partial cross-sectional perspective view of the penetrating portion 1a of FIG. Each of the intermediate members 24a to 24c has a large opening 243 at the end on the window 61 side in FIG. 2 (the left end in FIG. 3) with respect to the propagation direction of the laser light L in FIG. A small opening 244 smaller than the large opening 243 is provided at the end portion on the cavity S ₁ side (the right end portion in FIG. 3), and the shape is narrowed like a funnel from the large opening 243 to the small opening 244. In addition, the outer peripheral edge of the edge part by the side of the window 61 of FIG. 2 of each intermediate member 24a-24c is in contact with the inner peripheral surface of the penetration part 1a.

The diameter _{D 1} of the large aperture 243 is approximately equal to the inner diameter of the through portion 1a. The diameter D ₂ of the small opening 244, the diameter of the beam cross section of the laser beam L in FIG. 2 (hereinafter, referred to as the beam diameter.) Substantially equal. Specifically, the diameter D ₂ of the small aperture 244, when the beam diameter of the laser beam L in FIG. 2 is D, greater than D, is selected below a value D + 10 mm. The beam diameter of the laser beam L in FIG. 2 is about 70 mm wide × 100 mm long.

  FIG. 4 is an enlarged view of the inclined member 25 of FIG. 4A is a plan view viewed from the Z direction, and FIG. 4B is a cross-sectional view perpendicular to the Z axis. The inclined member 25 has a shape obtained by forming a through hole 252 extending from the upper bottom surface to the lower bottom surface of a truncated cone having a trapezoidal cross section parallel to the thickness direction. The size of the opening (hereinafter referred to as the top opening) 252a of the through cone 252 on the upper bottom surface side of the truncated cone is substantially equal to the size of the upper bottom surface of the truncated cone. An opening (hereinafter referred to as a bottom opening) 252b of the through-hole 252 on the lower bottom surface side of the truncated cone is larger than the top opening 252a. The inner peripheral surface of the through hole 252 extends in a tapered shape from the top opening 252a toward the bottom opening 252b.

The shapes of the top opening 252a and the bottom opening 252b are both circular in plan view. The diameter _{D 3} of the top opening 252a is substantially equal to the diameter of the laser beam L in FIG. Specifically, the diameter D ₃ of the top opening 252a, when the diameter of the laser beam L in FIG. 2 is D, greater than D, is selected below a value D + 10 mm. On the other hand, the diameter _{D 4} of the bottom opening 252b is substantially equal to the diameter of the first opening 21 of Figure 2. Specifically, the diameter of the bottom opening 252b with a diameter _{D 4} and the first opening 21 of Figure 2 are both about 142 mm.

Note that an inclined surface 251 shown in FIG. 2 is formed by a surface corresponding to the side surface of the truncated cone. A plurality of bolt holes 253 penetrating to the back surface corresponding to the lower bottom surface of the truncated cone are formed in the inclined surface 251 at intervals in the circumferential direction. In other words, the inclined member 25 by a bolt, the rear surface is mounted in contact with the inner wall surface of the main cavity S ₁ of FIG.

  FIG. 5 shows a modification of the inclined member 25. FIG. 5A is a plan view seen from the Z direction, and FIG. 5B is a cross-sectional view perpendicular to the Z axis. In this example, the top opening 252a and the bottom opening 252b have a rectangular shape. The inclined member 25 is attached so that, for example, the long sides of the rectangle representing the shapes of the top opening 252a and the bottom opening 252b are parallel to the X axis in FIG. Note that the length of the short side of the top opening 252a is selected to be larger than D and D + 10 mm or less, where D is the beam diameter of the laser light L in FIG. The length of the long side of the top opening 252a is selected to be greater than D and not greater than D + 10 mm.

Returning to FIG. 2, the description will be continued. As described above, in the main cavity S within _1, the gas flow F flowing in the X direction is formed. Further, the discharge between the discharge electrodes 2a (see FIG. 1 (a)) and 2b, shock wave toward the intermediate cavity S ₂ is generated. The main cavity S ₁ due to the presence of impurities, the gas flow F and shock waves carry the impurities. Therefore, in order to prevent impurities from adhering to the inner surface of the window 61, it is necessary to prevent the gas flow F and the shock wave from reaching the inner surface of the window 61.

According to this embodiment, the laser medium gas supplied from the gas supply port 23a and 23b in the intermediate cavity S in _2, flows out from the intermediate cavity S ₂ in the main cavity S _1. Thus, the shock wave and the gas flow F such that occurred in the main cavity S within _1, entry into the intermediate cavity S ₂ is prevented. For this reason, impurities carried by the gas flow F and the shock wave can be prevented from adhering to the inner surface of the window 61.

Note that the higher the outflow rate of the laser medium gas from the intermediate cavity S ₂ to the main cavity S ₁ , the lower the probability that the gas flow F, shock wave, etc. will enter the intermediate cavity S ₂ . However, since the delivery pressure and the delivery rate of the laser medium gas by the pump 12 shown in FIG. 1 (b) is limited only by delivery pressure and delivery rate of the pump 12 shown in FIG. 1 (b), the main from the intermediate cavity S ₂ the possible to increase the outflow speed of the laser medium gas to the cavity S ₁ is limited.

In this regard, the inclined surface 251 of the inclined member 25 is protruded toward the center of the first opening 21 from the edge of the first opening 21, and the top opening 252 a in FIG. 4 is made smaller than the first opening 21. since the, compared to the case without the tilting member 25, it is possible to increase the outflow speed of the laser medium gas from the intermediate cavity S ₂ to the main cavity S _1. Therefore, without increasing the size of the pump 12 in FIG. 1 (b), can be suppressed from entering into the intermediate cavity S _2, such as gas flow F and shock waves.

Further, the gas flow F that has reached the inclined member 25 from the first rectifying plate 26 a first flows so as to climb the inclined surface 251 along the inclined surface 251. For this reason, the traveling direction of the gas flow F is changed to a direction away from the window 61. Accordingly, entry into the intermediate cavity S ₂ of the gas flow F is prevented. The gas flow F whose traveling direction has been changed in the direction away from the window 61 flows toward the second rectifying plate 26b and flows down the inclined surface 251 along the inclined surface 251. This prevents the gas flow F whose traveling direction has been changed from forming a turbulent flow.

Further, a virtual gas flow towards the main cavity _{S 1} to the window 61 in the Z direction (hereinafter, referred to as virtual gas stream.) When assuming the second surface 242 of the intermediate member 24a~24c is, the virtual gas Demonstrate resistance to flow. The second surface 242, since the inclined so as to approach the main cavity S ₁ toward the optical axis of the laser beam L from the inner circumferential surface of the through portion 1a, the second surface 242 is a virtual gas stream The resistance exerted is larger than the resistance exhibited by the perforated disk in which the opening having the same size as the small opening 244 in FIG. In addition, since the plurality of intermediate members 24a to 24c are discretely arranged with respect to the Z direction, a large resistance can be exhibited against the virtual gas flow. Therefore, even if the gas flow F and the shock wave or the like enters the intermediate cavity S _2, reaching the window 61 internal surface such as those gas flow F and shock waves is prevented.

On the other hand, the first face 241 of the intermediate member 24a~24c, since inclined so as to approach the main cavity S ₁ toward the optical axis of the laser beam L from the inner circumferential surface of the through portion 1a, the gas supply port 24a and 24b is supplied to the intermediate cavity S in ₂ from the main cavity flow of the laser medium gas toward the S ₁ (hereinafter, referred to as purge gas stream.) it is possible to reduce the resistance exerted against. Specifically, the resistance exerted by the first surface 241 against the purified gas flow is smaller than the provision that the perforated disk exerts against the purified gas flow. As described above, the intermediate members 25a to 25c exhibit the function of preventing the gas flow F and shock waves from reaching the inner surface of the window 61 while suppressing the loss of the delivery pressure of the pump 12 of FIG. .

As described above, according to this embodiment, since reaching the entrance and window 61 internal surface into the intermediate cavity S ₁ such as a gas flow F and shock waves can be prevented, thereby preventing contamination of the window 61. Therefore, it is possible to prevent a decrease in the output of the laser beam L due to a decrease in the light transmittance of the window 61, a breakage of the window 61 due to the impurities adhering to the window 61 absorbing the laser beam L, and the like.

FIG. 6 shows a modification of the inclined member 25 of FIG. In this example, the inclined member is divided into a first inclined member 31 and a second inclined member 32 that are arranged to face each other in the X direction with the first opening 21 interposed therebetween. The first and second inclined members 31 and 32 are provided around the first opening 21 on the inner wall surface of the main cavity S _{1 in} FIG. 2, respectively, and as the center of the first opening 21 approaches, having first and second inclined surfaces 311 and 321 the height from the inner wall surface of the cavity S ₁ is inclined to be higher.

The traveling direction of the gas flow F on the first inclined surface 311 is changed so as to move away from the window 61 of FIG. Thus, the gas flow F, entry into the intermediate cavity S ₂ in FIG. 2 can be prevented. The gas flow F whose traveling direction is changed on the first inclined surface 311 flows along the second inclined surface 321 toward the second rectifying plate 26b of FIG. This prevents the gas flow F whose traveling direction has been changed from forming a turbulent flow.

Note that the top portion of the first inclined surface 311, the height h ₁ from the inner wall surface of the main cavity S ₁ in FIG. 2, the top portion of the second inclined surface 321, of FIG. 2 of the main cavity S ₁ a height h ₂ from the inner wall surface may be different. For _{example, h} 1> h ₂ and may be configured such that. Also, it is configured to omit the second inclined member 32, the effect of preventing the gas flow F enters into the intermediate cavity S ₂ in FIG. 2 is considered to be obtained.

FIG. 7 shows a cross-sectional view of an excimer laser oscillation device according to another embodiment. Configuration In this example, the intermediate cavity S _2, a small diameter portion S _2a throttled to the beam diameter and the value substantially matches the inner diameter of the laser beam L, by a large large diameter portion S _2b of inner diameter than the small diameter portion S _2a is doing. The large diameter portion S 2 _b is defined at the end portion on the window 61 side in the housing 6. The small diameter portion _S2a is defined from the end of the large diameter portion _S2b on the first opening 21 side to the first opening 21. Since the inner diameter of the small diameter portion S _2a, squeezed until the beam diameter substantially matching values of the laser beam L, while omitting the intermediate member 24a~24c in Figure 2, the inner surface of the through-hole 311 of the tilting member 31 is tapered Instead of a shape, it is formed in a straight shape.

In this modification, the laser medium gas is supplied to the large diameter portion S _2b from the gas supply port 23a and 23b. Since then supplied to the laser medium gas to the large larger diameter portion S _2b of relatively inner diameter, despite targeted inner diameter of the small diameter portion S _2a until substantially coincident with the beam diameter of the laser beam L, FIG. 1 The increase in load applied to the pump 12 in (b) can be mitigated. The laser medium gas supplied to the large diameter portion S _2b flows out to the main cavity S ₁ through the small diameter portion S _2a . Since the step portion 31 at the boundary between the large diameter portion S _2b and the small diameter portion S _2a is formed smoothly, a decrease in the flow rate of the purified gas flow toward the main cavity S ₁ is prevented. Since the inner diameter of the small-diameter portion S _2a is substantially matched with the beam diameter of the laser light L, the outflow speed of the purified gas flowing out from the intermediate cavity S ₂ to the main cavity S ₁ can be increased. Therefore, it is possible to prevent the gas flow F and the shock wave or the like of the main cavity S ₁ enters the intermediate cavity S _2. As a result, contamination of the window 61 is prevented.

FIG. 8 is a sectional view of an excimer laser oscillation device according to still another embodiment. In this example, a configuration in which the cross section of the intermediate cavity S ₂ perpendicular to the light propagation direction of the laser light L continuously decreases from the second opening 22 toward the first opening 21. . The diameter of the first opening 21 is substantially the same as the beam diameter of the laser light L. Thus, it is possible to increase the outflow rate of the purge gas stream from the intermediate cavity S ₂ to the main cavity S _1, can be prevented from entering the gas flow F and shock waves of the intermediate cavity S _2. Incidentally, the second opening 22, the through hole 311 of the tilting member 31 may be formed continuously or stepwise tapered surface over the opening of the main cavity S ₁ side.

As mentioned above, although the Example was described, this invention is not limited to this. For example, the shape of the inclined member 25 and the intermediate members 24a to 24c in FIG. 2 may not be a rotating body. Other intermediate members equivalent to the intermediate members 24 a to 24 c may be provided in the housing 6. The first surface 241 and the second surface 242 of each of the intermediate members 24a to 24c may not be parallel. The first surface 241 and the second surface 242 may not be parallel between the intermediate members. Although the internal mirror type gas laser oscillation device has been described, the present invention can also be applied to an internal mirror type gas laser oscillation device provided with a partial reflection mirror or a total reflection mirror instead of the window. Although the excimer laser oscillation device has been described, the present invention can also be applied to other gas laser oscillation devices such as a CO ₂ laser oscillation device. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

It is a diagram showing an excimer laser oscillation device, (a) is a schematic cross-sectional view perpendicular to the optical axis of laser light, (b) is a schematic side view. It is sectional drawing which expanded and showed the Z direction one end part of the vessel. It is a fragmentary sectional perspective view which shows an intermediate member. It is a diagram which shows an inclined member, Comprising: (a) is a top view, (b) is sectional drawing. It is a diagram which shows another inclination member, Comprising: (a) is a top view, (b) is sectional drawing. It is a perspective schematic diagram showing other inclination members. It is sectional drawing of the excimer laser oscillation apparatus by another Example. It is sectional drawing of the excimer laser oscillation apparatus by other Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vessel (container main body), 2a, 2b ... Discharge electrode (exciter), 3 ... Gas flow path, 4 ... Blower (gas flow formation means), 5 ... Gate valve, 6 ... Housing (tubular body), 7 DESCRIPTION OF SYMBOLS 1st mirror holder, 8 ... 2nd mirror holder, 10 ... Gas processor, 11 ... Filter, 12 ... Pump, 13 ... Gas line, 21 ... 1st opening part, 22 ... 2nd opening part, 23a , 23b ... gas supply ports, 24a, 24b, 24c ... intermediate members, 25 ... inclined members, 251 ... inclined surfaces, 26a, 26b ... rectifying plates, 61 ... windows (plate-like bodies), 71 ... partial reflectors, 81 ... Total reflection mirror, S ₁ ... main cavity, S ₂ ... intermediate cavity, F ... gas flow, L ... laser light.

Claims (16)

A main cavity in which a laser medium gas and an exciter for exciting the laser medium gas are accommodated, and an intermediate cavity through which laser light generated by the excitation of the laser medium gas in the main cavity by the exciter passes. Thus, with respect to the propagation direction of the laser beam, an intermediate cavity is configured such that one end is a first opening that opens on the inner wall surface of the main cavity and the other end is a second opening that communicates with an external space. A container structure defining
A plate-like body that is held by the container structure and closes the second opening;
An inclined surface that is provided around the first opening on the inner wall surface of the main cavity and is inclined so that the height from the inner wall surface of the main cavity increases as it approaches the center of the first opening. A gas laser oscillation device comprising an inclined member having The gas laser oscillation device according to claim 1, wherein the inclined surface of the inclined member is disposed so as to surround the first opening portion around the entire circumference. 3. The gas laser oscillation device according to claim 1, wherein the inclined surface protrudes closer to a center side of the first opening than an edge of the first opening. The gas laser oscillation device according to claim 1, wherein the inclined member is made of an insulator. 5. The gas laser oscillation according to claim 1, further comprising gas flow forming means for forming a gas flow of the laser medium gas flowing in a direction intersecting a propagation direction of the laser light in the main cavity. apparatus. Furthermore, the gas laser oscillation apparatus in any one of Claims 1-5 provided with the gas supply port which supplies gas in the said intermediate cave. Further, the intermediate member protrudes from the inner wall surface of the intermediate cavity toward the optical axis of the laser beam, and the surface on the plate-like body side approaches the optical axis of the laser beam from the inner wall surface of the intermediate cavity. The gas laser oscillation device according to any one of claims 1 to 5, further comprising an intermediate member inclined so as to approach the main cavity. The gas laser oscillation device according to claim 7, wherein a surface of the intermediate member on the main cavity side is inclined so as to approach the main cavity as it approaches the optical axis of the laser light from the inner wall surface of the intermediate cavity. The intermediate member has a large opening at the end on the plate-like body side with respect to the propagation direction of the laser light, and has a small opening smaller than the large opening at the end on the main cavity side. The gas laser oscillation device according to claim 7 or 8, wherein the gas laser oscillation device has a shape narrowed like a funnel over the small opening. The at least one other intermediate member having the same shape as the intermediate member is provided in the intermediate cavity at a position different from each other with respect to the propagation direction of the laser light. Gas laser oscillator. Furthermore, the gas supply port which supplies gas in the said intermediate | middle cavity from the position between the said plate-shaped body and the said intermediate member regarding the propagation direction of the said laser beam is provided in any one of Claims 7-10. Gas laser oscillation device. The gas laser oscillation device according to any one of claims 1 to 11, wherein a size of the first opening is smaller than a size of the second opening. The cross section of the intermediate cavity perpendicular to the light propagation direction of the laser light becomes smaller stepwise or continuously as it approaches the first opening from the second opening. Gas laser oscillation device. The container structure is connected to the container main body at a position corresponding to the through hole, and a container main body having a through hole that defines the main cavity inside and communicates the main cavity with an external space. The gas laser oscillation device according to claim 1, comprising a cylindrical body that defines the intermediate cavity together with the container body. A main cavity in which a laser medium gas and an exciter for exciting the laser medium gas are accommodated, and an intermediate cavity through which laser light generated by the excitation of the laser medium gas in the main cavity by the exciter passes. Thus, with respect to the propagation direction of the laser beam, an intermediate cavity is configured such that one end is a first opening that opens on the inner wall surface of the main cavity and the other end is a second opening that communicates with an external space. A container structure defining
A plate-like body that is held by the container structure and closes the second opening;
An intermediate member that protrudes from the inner wall surface of the intermediate cavity toward the optical axis of the laser beam, and the surface on the plate-like body side approaches the optical axis of the laser beam from the inner wall surface of the intermediate cavity. A gas laser oscillation device comprising an intermediate member inclined so as to approach the main cavity. A main cavity in which a laser medium gas and an exciter for exciting the laser medium gas are accommodated, and an intermediate cavity through which laser light generated by the excitation of the laser medium gas in the main cavity by the exciter passes. With respect to the propagation direction of the laser beam, one end is configured as a first opening that is opened in the inner wall surface of the main cavity, and the other end is configured as a second opening that communicates with an external space. A container structure defining an intermediate cavity in which the size of one opening is smaller than the size of the second opening;
A gas laser oscillation apparatus comprising: a plate-like body that is held by the container structure and closes the second opening.

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