JPH0888426A - Optical parts protecting device in laser device - Google Patents

Abstract

PURPOSE: To shield optical parts off the outside air for preventing being damaged even at maintenance for replacing windows, etc., by, in accordance with dismounting of a laser chamber, providing a shutter which stops a laser light introduction opening of a body. CONSTITUTION: Relating to the surface of a cavity plate 15 on the rear side (narrow zoned side) and a cavity plate 16 on the front side (laser light take-out side), on the surface on the side where laser light emitting openings 12a and 13a of ducts 12 and 13 are connected, a shutter 4 which opens/closes a laser light path 18 is assigned while its sliding is allowed. Then, relating to the shutter 4, guides which guides the shutter 4 in the direction parallel to the direction B a laser chamber 1 is taken out are provided on both sides. On the shutter 4, a spring 5 is so assigned that it expands/shrinks in the direction the shutter 4 moves, and, a pin 3 which is touched to a plate 2 provided on the end surface of the laser chamber 1 is assigned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for protecting an optical component constituting a laser device from the outside air.

[0002]

2. Description of the Related Art When a gas laser oscillates, the generation of dust and particles due to the reaction between electrodes and laser gas is unavoidable.
Such dust and dirt adhere to the window of the laser chamber to reduce the light transmittance of the window, resulting in a decrease in laser output and instability. In particular, when an excimer laser is used as a light source of an exposure apparatus, fluctuations in laser output power cause a significant decrease in exposure quality, so it is essential to keep the window clean by replacing and cleaning the window. There is. Further, the discharge electrodes and the like in the laser chamber deteriorate with the elapse of discharge time and require replacement.

As described above, in the gas laser device, it is necessary to clean the window and replace the consumables such as the discharge electrode. For that purpose, the maintenance can be facilitated by easily attaching and detaching the laser chamber. It becomes important.

Therefore, the present applicant has filed Japanese Patent Application No. 61-151.
In 391 etc., we proposed a structure that pulls out only the laser chamber in a direction substantially perpendicular to the optical axis, and makes it possible to easily separate and take out only the laser chamber that has a higher maintenance frequency than other optical parts and electric circuits, and perform maintenance. We are trying to make it easier.

On the other hand, an excimer laser that emits light in the ultraviolet region has a large amount of light energy. Therefore, unless the surfaces of various optical parts (mirrors, etalons, gratings, prisms, etc.) are kept clean, dust is generated by the laser light. ,
Dust, oil, etc. may be seized, resulting in damage to the optical components.

Therefore, the present applicant has filed Japanese Patent Application No. 3-3528.
In No. 05, the laser chamber is attached so that the laser light inlet provided in the housing in which the optical components that form the laser resonator are provided and the laser light outlet provided in the laser chamber are connected to each other, and the housing is attached. The optical components inside the body are protected from the outside air, and laser oscillation is performed. In this case, the casing is made airtight by using nitrogen gas or the like as a purge gas.

[0007]

However, in the above-mentioned prior art, the laser light guide entrance of the housing is only closed by being connected to the laser light exit entrance of the laser chamber, and once the laser chamber is opened. Is removed,
The laser light guide inlet of the housing is communicated with the outside air, and dust and dust contained in the outside air adhere to the optical components inside the housing.

Therefore, there is a possibility that the optical components may be damaged by the seizure of dust, dust, oil, etc. by the laser light.

The present invention has been made in view of the above circumstances, and provides a device for protecting an optical component from damage by blocking the optical component from the outside air even during maintenance such as replacement of a window. That is the purpose.

[0010]

Therefore, according to the present invention,
By mounting the laser chamber so that the laser light entrance provided in the housing in which the optical components that make up the laser device are built-in and the laser light exit provided in the laser chamber are connected, In an optical component protection device for a laser device that protects an optical component from the outside air and performs laser oscillation, a connection state between a laser light guide inlet of the casing and a laser light emission outlet of the laser chamber is released. As described above, a shutter is provided to close the laser light guide entrance of the housing when the laser chamber is removed.

[0011]

According to such a structure, as shown in FIGS.
As shown in FIG. 2, the shutter 4 is moved to the housing 7 in response to the removal of the laser chamber 1 so that the laser light entrance 18 of the housing 7 and the laser light exit 13a of the laser chamber 1 are disconnected. The laser light guide inlet 18 is closed to shield the optical component 11 in the housing 7 from the outside air and protect it from damage.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical component protection device in a laser device according to the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a top view of the gas laser device of the embodiment, showing how the laser chamber 1 is positioned and mounted at a predetermined position by a positioning rail (not shown). On the other hand, FIG. 1B is a top view showing a state in which the laser chamber 1 is detached from the apparatus. 2A is a view showing a cross section taken along the line AA in FIG. 1A, and FIG. 2B is a cross sectional view taken along the line AA corresponding to FIG. 1B.

The laser chamber 1 is provided with a discharge electrode (not shown) and the like inside, and discharges and excites the enclosed gas to perform laser oscillation. In the case of excimer laser, Kr, Ar, Xe, etc. are used as rare gas, F2, Cl2, etc. are used as halogen gas, and Ne, He are used as buffer gas.
Etc. are used, and a combination of gases according to a desired wavelength is selected and sealed in the laser chamber 1.

Ducts 12, 13 are provided at both left and right ends of the laser chamber 1, and the left and right windows 1a, 1 are provided.
It functions as a passage for the laser light L that has passed through a.

The laser chamber 1 is supported from both sides by the left and right cavity plates 15 and 16. The left and right cavity plates 15 and 16 are connected by an invar rod 17.

A narrow band box 6 is arranged in the cavity plate 15. Inside the narrow band box 6, a grating 8, a prism 9, 10 for selecting a wavelength of light to narrow the band. Narrowing band optics are provided.

A laser beam passage 18 is arranged in the cavity plate 15, and the passage 18 communicates with the inside of the narrow band (rear) box 6.

Therefore, the laser light emitting port 12 of the duct 12
By connecting a to the laser beam passage 18, the laser beam can reciprocate between the laser chamber 1 and the narrow band box 6, and the grating 8 and the prisms 9 and 10 can narrow the light band. Done.

Further, the laser beam emitting port 12a of the duct 12
Is connected to the laser light path 18, the narrow band box 6 is shielded from the outside air and made airtight. That is, the duct 12 also has a function of making the passage of the laser light and the narrow band box 6 airtight. Similarly, the cavity plate 16 is provided with a front box 7, and inside the front box 7, a front mirror 11 which is an optical component for extracting the laser light L to the outside is provided. .

A laser beam passage 18 is arranged in the cavity plate 16, and the passage 18 communicates with the inside of the front box 7.

Therefore, the laser light emitting port 13 of the duct 13
By connecting a to the laser beam passage 18, the laser beam can reciprocate between the inside of the laser chamber 1 and the inside of the front box 7, and the front mirror 1
Laser light L is extracted to the outside via 1 as indicated by an arrow.

As described above, the grating 8, the prisms 9 and 10 in the narrow band box 6 and the front mirror 11 in the front box 7 constitute a resonator for laser light.

Further, the laser beam emitting port 13a of the duct 13
Is connected to the laser light passage 18, the front box 7 is shielded from the outside air and made airtight. In other words, the duct 13 is used for the passage of the laser light and the front box 7.
It also has the function of making airtight.

A purge gas such as nitrogen is introduced into the narrow band box 6 and the front box 7 through a pipe (not shown), and the purge gas keeps optical components such as the grating 8 clean.

The surfaces of the cavity plate 15 on the rear side (band narrowing side) and the cavity plate 16 on the front side (laser light extraction side), which are ducts 12,
A shutter 4 that opens and closes a laser beam passage 18 is slidably arranged on the surface of the side 13 of the laser beam emitting port 12a, 13a connected to.

Since the mechanism of the shutter 4 is common to both the plates 15 and 16, the front side cavity plate 16 will be described as a representative.

That is, as shown in FIG. 2A, guides 4a and 4a for guiding the shutter 4 are provided in parallel with the direction B for removing the laser chamber 1. Guide 4
2a and 4a slidably support both side surfaces of the shutter 4, as shown in FIG. Shutter 4
A spring 5 is arranged so as to expand and contract in the moving direction of the shutter 4, and a pin 3 that comes into contact with a plate 2 provided on the end surface of the laser chamber 1 is arranged therein.

Therefore, the positioning of the laser chamber 1
At the time of mounting, the plate 2 of the laser chamber 1 is locked to the pin 3 of the shutter 4, and the shutter 4 is moved against the spring force of the spring 5, and as a result, as shown in FIG. Are positioned so as to open the laser beam passage 18. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam passage 18, and the laser beam is oscillated with the front box 7 kept airtight.

Therefore, when the laser chamber 1 is removed in the direction shown by the arrow B, the shutter 4 is moved by the urging force of the spring 5 (see the arrow C in FIG. 1B), and the shutter 4 passes through the laser beam path. It is positioned so as to close 18 (see FIG. 2B). Thus, even if the laser chamber 1 is removed, the airtight state of the front box 7 is maintained.

Thus, according to this embodiment, as the laser chamber 1 is removed, the laser light passage 18
Since the shutter 4 that closes the door is provided, the optical components inside the boxes 6 and 7 can be shielded from the outside air even during maintenance, and can be effectively protected from damage caused by dust adhesion or the like.

The shutter 4 is a mechanism that closes the laser light passage 18 when the laser chamber 1 is removed, and does not close the laser light passage 18 when the laser chamber 1 is mounted. It does not occur that the laser light passage is closed during the oscillation of the laser light, such as a mechanism in which a shutter is provided in the middle of the light passage. That is, as long as the laser chamber 1 is mounted and the plate 2 is in contact with the pin 4 of the shutter 4,
The shutter 4 does not close the laser light passage 18. Further, even if the shutter 4 moves to the closing side due to breakage of the plate 2 or the like, the shutter 4 only contacts the openings 12a, 13a of the ducts 12, 13 and does not close the laser light passage 18.

Although the spring 5 is used in the embodiment, any elastic body such as rubber can be used instead.

Next, a modified example of the shutter using a spring will be described. 3 (a) and 3 (b) are shown in FIG.
It is a figure corresponding to each of (b).

That is, as shown in FIG. 3A, the shutter 4 is rotatably arranged by a rotating pin 19 as shown by an arrow E, and a biasing force of a spring is provided on the side where the laser light passage 18 is closed. A spring 5 is attached to the shutter 4 so that

Therefore, at the time of positioning and mounting the laser chamber 1, the plate 2 of the laser chamber 1 is fitted with the shutter 4
3 and the shutter 4 is rotated against the spring force of the spring 5, and as a result, as shown in FIG.
The shutter 4 is positioned so as to open the laser beam passage 18. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam passage 18, and the laser beam is oscillated with the front box 7 kept airtight.

Therefore, when the laser chamber 1 is removed in the direction shown by the arrows B to B ', the shutter 4 is rotated by the urging force of the spring 5, and the shutter 4 closes the laser beam passage 18. (See FIG. 3B). Thus, even if the laser chamber 1 is removed, the airtight state of the front box 7 is maintained.

In this embodiment as well, any elastic body such as rubber can be used instead of the spring 5.

Next, a shutter using an air cylinder instead of an elastic body such as a spring will be described. FIG. 4 (a),
1B is a diagram corresponding to FIGS. 1A and 1B, respectively.

As shown in FIG. 4 (a), the drive control section for driving and controlling the air cylinder 23 supplies the high pressure gas supply source 22 for supplying high pressure air and the air supplied from this high pressure gas supply source 22. The pipe 21 is configured to pass through and lead to the air cylinder 23, and a pilot valve 20 that is provided in the middle of the pipe 21 and that opens and closes the valve according to the expansion and contraction of the rod 20a to supply and cut off air.

The air cylinders 23, 23 are arranged in the respective cavity plates 15, 16 and the rods of the cylinders are connected to the shutters 4, 4.

Therefore, when the laser chamber 1 is positioned and mounted, the side surface of the laser chamber 1 abuts on the rod 20a of the pilot valve 20 and retracts it.
The pilot valve 20 is closed and air is no longer supplied to the air cylinder 23. As a result, the air cylinder 23
The rod of (1) retracts to move the shutter 4 to the open position of the laser light passage 18. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam passage 18, and the laser beam is oscillated with the front box 7 kept airtight.

Therefore, when the laser chamber 1 is removed in the direction indicated by the arrow B, the side surface of the laser chamber 1 is not brought into contact with the rod 20a of the pilot valve 20, as shown in FIG. The rod 20a extends as shown by an arrow G, the pilot valve 20 is opened, and the air flows through the air cylinder 23 through the valve 20.
Will be supplied to. As a result, the air cylinder 23
The rod extends to move the shutter 4 to the closed position of the laser light passage 18 as shown by arrow F. In this way, the airtight state of the front box 7 is maintained even if the laser chamber 1 is removed.

Although air is supplied in this embodiment, any kind of gas can be used as the gas to be supplied. Alternatively, liquid may be used instead of gas, and the shutter may be driven by hydraulic pressure.

Next, an embodiment using a linear actuator as an actuator for driving the shutter will be described. 5 (a) and 5 (b) are the same as FIGS. 1 (a) and 1 (b).
It is a figure corresponding to each.

As shown in FIG. 5A, the drive control unit for controlling the drive of the linear actuator 26 includes the rod 24.
The sensor 24 is configured to detect whether or not the laser chamber 1 is removed according to the expansion and contraction of a, and the controller 25 that outputs a shutter open / close signal to the linear actuator 26 based on the detection signal of the sensor 24. .
The linear actuators 26, 26 are arranged on the respective cavity plates 15, 16 and their rods are connected to the shutters 4, 4.

Therefore, when the laser chamber 1 is positioned and mounted, the side surface of the laser chamber 1 abuts on the rod 24a of the sensor 24 and retracts the rod 24a.
Detects that the laser chamber 1 has not been detached (mounted), and the controller 25 sends a signal of "shutter open" to the linear actuator 26 according to the detection result. As a result, the rod of the linear actuator 26 retracts to move the shutter 4 to the open position of the laser light passage 18. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam passage 18, and the laser beam is oscillated with the front box 7 kept airtight.

Therefore, when the laser chamber 1 is removed in the direction shown by the arrow B, the side surface of the laser chamber 1 is not brought into contact with the rod 24a of the sensor 24 as shown in FIG. 24a expands as shown by arrow I, the sensor 24 detects that the laser chamber 1 has been removed, and the controller 25 sends a "shutter closed" signal to the linear actuator 26 according to the detection result. . As a result, the rod of the linear actuator 26 expands to move the shutter 4 to the closed position of the laser light passage 18 as shown by the arrow H. In this way, the airtight state of the front box 7 is maintained even if the laser chamber 1 is removed.

[0049]

As described above, according to the present invention,
Not only during laser oscillation but also during maintenance such as window replacement, the optical parts of the laser device can be shielded from the outside air, so that the optical parts can be effectively protected from damage and the durability of the device can be improved. Can be dramatically improved.

[Brief description of drawings]

FIG. 1A and FIG. 1B are views showing a configuration of an embodiment of an optical component protection device in a laser device according to the present invention.

2A and 2B are sectional views taken along the line AA of FIG. 1A, and FIG. 2C is a sectional view taken along the line D-D of FIG. 2A.

3 (a) and 3 (b) are diagrams showing modified examples of the configuration shown in FIGS. 2 (a) and 2 (b).

4A and 4B are views corresponding to FIGS. 1A and 1B, and are views showing another embodiment using an air cylinder as an actuator.

5 (a) and 5 (b) are diagrams corresponding to FIGS. 1 (a) and 1 (b), and are diagrams showing another embodiment using a linear actuator as an actuator.

[Explanation of symbols]

 1 Laser Chamber 4 Shutter 6 Narrow Band (Rear) Box 7 Front Box 8 Grating 9 Prism 10 Prism 11 Front Mirror 12 Duct 13 Duct 18 Laser Light Path

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[Procedure amendment]

[Submission date] January 9, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1A and FIG. 1B are views showing a configuration of an embodiment of an optical component protection device in a laser device according to the present invention.

2A and 2B are sectional views taken along the line AA of FIG. 1A, and FIG. 2C is a sectional view taken along the line D-D of FIG. 2A.

3 (a) and 3 (b) are diagrams showing modified examples of the configuration shown in FIGS. 2 (a) and 2 (b).

4A and 4B are views corresponding to FIGS. 1A and 1B, and are views showing another embodiment in which an air silling is used as an actuator.

FIG. 5 is a diagram corresponding to FIGS. 1A and 1B and is a diagram showing another embodiment using a linear actuator as an actuator.

[Explanation of symbols] 1 laser chamber 4 shutter 6 narrow band (rear) box 7 front box 8 grating 9 prism 10 prism 11 front mirror 12 duct 13 duct 18 laser light passage

Claims (1)

[Claims] 1. By mounting the laser chamber so that a laser light inlet provided in a housing in which an optical component constituting a laser device is incorporated and a laser light emitting outlet provided in a laser chamber are connected to each other. In an optical component protection device for a laser device that protects optical components in the housing from the outside air and performs laser oscillation, a connection between a laser light inlet of the housing and a laser light emitting port of the laser chamber An optical component protection device in a laser device, wherein a shutter is provided for closing a laser light guide entrance of the casing according to removal of the laser chamber so that the state is released.