JP3909873B2 - Optical component protection device in laser device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an apparatus for protecting optical components constituting a laser apparatus from outside air.
[0002]
[Prior art]
When a gas laser oscillates, dust and dust are inevitably generated due to the reaction between the electrode and the laser gas, and such dust and dust adhere to the window of the laser chamber, reducing the light transmittance of the window, and as a result, the laser output Cause deterioration and instability. In particular, when an excimer laser is used as the light source of an exposure apparatus, fluctuations in the 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. Yes. In addition, the discharge electrodes and the like in the laser chamber deteriorate as the number of discharges increases, and require replacement.
[0003]
As described above, in the gas laser apparatus, it is necessary to clean the window and replace consumables such as the discharge electrode. For this purpose, it is important to facilitate the maintenance by easily attaching and detaching the laser chamber. .
[0004]
In view of this, the present applicant proposed in Japanese Patent Application No. 61-151391 etc. a structure in which only the laser chamber is drawn out in a direction substantially perpendicular to the optical axis, and the laser chamber is more frequently maintained than other optical components and electrical circuits. It is possible to easily remove and take out only, and to facilitate maintenance.
[0005]
On the other hand, an excimer laser that emits light in the ultraviolet region has a large light energy. Therefore, unless the surfaces of various optical components (mirrors, etalons, gratings, prisms, etc.) are kept clean, dust, dust, Oil or the like may be burned out, resulting in damage to the optical components.
[0006]
In view of this, the present applicant, in Japanese Patent Application No. 3-352805, has a laser beam entrance provided in a housing in which an optical component constituting a laser resonator is incorporated, and a laser beam exit provided in a laser chamber. A laser chamber is attached so that the optical components in the housing are connected to protect the optical components in the housing from the outside air and to perform laser oscillation. In this case, the casing is hermetically sealed using nitrogen gas or the like as a purge gas.
[0007]
[Problems to be solved by the invention]
However, in the above prior art, the laser light entrance of the housing is only blocked by being connected to the laser light exit of the laser chamber, and once the laser chamber is removed, the laser in the housing is removed. The light entrance is communicated with the outside air, and dust, dust and the like contained in the outside air adhere to the optical components in the housing.
[0008]
For this reason, there is a possibility that the optical component is damaged by the burning of dust, dust, oil or the like by the laser beam.
[0009]
The present invention has been made in view of such a situation, and an object of the present invention is to provide an apparatus that protects an optical component from damage by blocking the optical component from outside air even during maintenance such as window replacement. It is what.
[0010]
[Means for Solving the Problems]
Therefore, in the present invention, the laser chamber is mounted so that the laser beam inlet provided in the housing containing the optical components constituting the laser device is connected to the laser beam exit provided in the laser chamber. By protecting the optical components in the housing from the outside air, and in the optical component protection device in the laser device configured to perform laser oscillation,
A shutter provided on a surface of the duct of the laser chamber to which the laser beam emission port is connected, movably in the direction of removing the laser chamber, and opens and closes the laser beam inlet;
At the time of positioning and mounting of the laser chamber, the laser chamber is moved and positioned at a position where the laser light entrance is opened as the laser chamber is mounted.
As the laser chamber is removed, a shutter that is moved to close the laser light entrance is positioned to maintain the airtight state of the housing.
[0011]
[Action]
According to such a configuration, as shown in FIGS. 1A and 1B, the connection state between the laser light inlet 18 of the housing 7 and the laser light outlet 13a of the laser chamber 1 is released. As the laser chamber 1 is removed, the shutter 4 closes the laser light inlet 18 of the housing 7 to block the optical component 11 in the housing 7 from the outside air and protect it from damage.
[0012]
【Example】
Embodiments of an optical component protection apparatus in a laser apparatus according to the present invention will be described below with reference to the drawings.
[0013]
FIG. 1A is a top view of the gas laser apparatus according to the embodiment, and shows a state in which 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 diagram 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.
[0014]
The laser chamber 1 has a discharge electrode (not shown) disposed therein, and discharges and excites the sealed gas to perform laser oscillation. In the case of an excimer laser, Kr, Ar, Xe, etc. are used as a rare gas, F2, Cl2, etc. are used as a halogen gas, Ne, He, etc. are used as a buffer gas, and a combination of gases corresponding to a desired wavelength is selected. It is enclosed in the chamber 1.
[0015]
Ducts 12 and 13 are disposed at the left and right ends of the laser chamber 1 and function as a path for the laser light L that has passed through the left and right windows 1a and 1a.
[0016]
Such a laser chamber 1 is supported from both sides by left and right cavity plates 15 and 16. The left and right cavity plates 15 and 16 are connected by an invar rod 17.
[0017]
A narrow band box 6 is disposed in the cavity plate 15, and a narrow band such as a grating 8 and a prism 9, 10 for narrowing the band by selecting the wavelength of light is disposed inside the narrow band box 6. Optical components are provided.
[0018]
A laser beam passage 18 is disposed in the cavity plate 15, and this passage 18 communicates with the inside of the narrow band (rear) box 6.
[0019]
Therefore, by connecting the laser beam emission port 12a of the duct 12 to the laser beam path 18, it becomes possible for the laser beam to reciprocate between the laser chamber 1 and the narrow band box 6, and the grating 8 and prism 9 described above. 10 narrows the bandwidth of the light.
[0020]
Further, the laser beam exit 12a of the duct 12 is connected to the laser beam path 18, so that the narrow band box 6 is cut off from the outside air and airtight. That is, the duct 12 has a function of hermetically sealing the laser beam passage and the narrow band box 6.
Similarly, a front box 7 is disposed in the cavity plate 16, and a front mirror 11, which is an optical component for extracting the laser light L to the outside, is disposed in the front box 7. .
[0021]
A laser beam passage 18 is disposed in the cavity plate 16, and this passage 18 communicates with the inside of the front box 7.
[0022]
Therefore, the laser beam exit port 13a of the duct 13 is connected to the laser beam path 18, so that the laser beam can reciprocate between the laser chamber 1 and the front box 7, and the front mirror 11 is The laser beam L is extracted to the outside as indicated by the arrows.
[0023]
As described above, the grating 8 and the prisms 9 and 10 in the narrow-band box 6 and the front mirror 11 in the front box 7 constitute a laser beam resonator and the like.
[0024]
Further, the laser beam exit port 13a of the duct 13 is connected to the laser beam passage 18, whereby the front box 7 is cut off from the outside air and airtight. That is, the duct 13 has a function of making the laser beam passage and the front box 7 airtight.
[0025]
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 optical components such as the grating 8 are kept clean by the purge gas.
[0026]
It is the surface of the cavity plate 15 on the rear side (narrow band side) and the cavity plate 16 on the front side (laser light extraction side) on the side to which the laser light emission ports 12a and 13a of the ducts 12 and 13 are connected. A shutter 4 that opens and closes the laser beam passage 18 is slidably disposed on the surface.
[0027]
Here, since the mechanism of the shutter 4 is common to both plates 15 and 16, the front side cavity plate 16 will be described as a representative.
[0028]
That is, as shown in FIG. 2A, guides 4a and 4a for guiding the shutter 4 are provided in parallel with the direction B in which the laser chamber 1 is removed. The guides 4a and 4a slidably support both side surfaces of the shutter 4 as shown in FIG. In the shutter 4, a spring 5 is disposed so as to expand and contract in the moving direction of the shutter 4, and a pin 3 that abuts on a plate 2 provided on an end surface of the laser chamber 1 is disposed.
[0029]
Therefore, when the laser chamber 1 is positioned and mounted, 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, FIG. As shown in (a), the shutter 4 is positioned at a position where the laser beam path 18 is opened. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam path 18, and the laser beam is oscillated while the front box 7 is hermetically sealed.
[0030]
Therefore, when the laser chamber 1 is removed in the direction indicated by the arrow B, the shutter 4 is moved by the biasing force of the spring 5 (see the arrow C in FIG. 1B), and the shutter 4 closes the laser light path 18. Is positioned at such a position (see FIG. 2B). Thus, even if the laser chamber 1 is removed, the airtight state of the front box 7 is maintained.
[0031]
As described above, according to this embodiment, the shutter 4 that closes the laser light path 18 is provided in accordance with the removal of the laser chamber 1, so that the optical components in the boxes 6 and 7 are maintained even during maintenance. It can be shielded from the outside air and effectively protected from damage caused by dust adhesion.
[0032]
The shutter 4 is a mechanism that closes the laser light path 18 in accordance with the removal of the laser chamber 1 and is a mechanism that does not close the laser light path 18 when the laser chamber 1 is mounted. A malfunction that closes the laser beam path during laser beam oscillation does not occur as in the mechanism in which a shutter is provided on the way. 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 beam path 18. Even if the shutter 4 moves to the closing side due to breakage of the plate 2 or the like, the shutter 4 only abuts the ports 12a and 13a of the ducts 12 and 13, and does not close the laser beam path 18.
[0033]
In the embodiment, the spring 5 is used, but any elastic body such as rubber can be used instead.
[0034]
Next, a modified example of the shutter using a spring will be described. FIGS. 3A and 3B correspond to FIGS. 2A and 2B, respectively.
[0035]
That is, as shown in FIG. 3A, the shutter 4 is rotatably arranged as indicated by the arrow E by the rotation pin 19, and the biasing force of the spring acts on the side closing the laser beam passage 18. A spring 5 is attached to the shutter 4.
[0036]
Therefore, when the laser chamber 1 is positioned and mounted, the plate 2 of the laser chamber 1 is locked to the pin 3 of the shutter 4, and the shutter 4 is rotated against the spring force of the spring 5, resulting in FIG. As shown in (a), the shutter 4 is positioned at a position where the laser beam path 18 is opened. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam path 18, and the laser beam is oscillated while the front box 7 is hermetically sealed.
[0037]
Therefore, when the laser chamber 1 is removed in the direction indicated by the arrows B to B ′, the shutter 4 is rotated by the urging force of the spring 5, and the shutter 4 is positioned to close the laser beam path 18. (See FIG. 3B). Thus, even if the laser chamber 1 is removed, the airtight state of the front box 7 is maintained.
[0038]
In this embodiment as well, an arbitrary elastic body such as rubber can be used instead of the spring 5.
[0039]
Next, a shutter using an air cylinder instead of an elastic body such as a spring will be described. FIGS. 4A and 4B correspond to FIGS. 1A and 1B, respectively.
[0040]
As shown in FIG. 4A, the drive control unit that drives and controls the air cylinder 23 passes the high-pressure gas supply source 22 that supplies high-pressure air and the air supplied from the high-pressure gas supply source 22. A pipe 21 leading to the air cylinder 23 and a pilot valve 20 provided in the middle of the pipe 21 to open and close the valve according to the expansion and contraction of the rod 20a to supply and shut off the air.
[0041]
The air cylinders 23 and 23 are disposed on the cavity plates 15 and 16, and the rods of the cylinders are connected to the shutters 4 and 4.
[0042]
Therefore, when the laser chamber 1 is positioned and mounted, the side surface of the laser chamber 1 comes into contact with the rod 20a of the pilot valve 20 and degenerates, so that the pilot valve 20 is closed and no air is supplied to the air cylinder 23. As a result, the rod of the air cylinder 23 is retracted to move the shutter 4 to the open position of the laser beam path 18. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam path 18, and the laser beam is oscillated while the front box 7 is hermetically sealed.
[0043]
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 pilot valve 20 opens as shown by the arrow G, and the air is supplied to the air cylinder 23 through the valve 20. As a result, the rod of the air cylinder 23 extends to move the shutter 4 to the closed position of the laser beam path 18 as indicated by the arrow F. Thus, even if the laser chamber 1 is removed, the airtight state of the front box 7 is maintained.
[0044]
In this embodiment, air is supplied, but any kind of gas can be used as the gas to be supplied. Alternatively, a liquid may be used instead of a gas, and the shutter may be driven by liquid pressure.
[0045]
Next, an embodiment using a linear actuator as an actuator for driving the shutter will be described. FIGS. 5A and 5B correspond to FIGS. 1A and 1B, respectively.
[0046]
As shown in FIG. 5A, the drive control unit that drives and controls the linear actuator 26 detects whether or not the laser chamber 1 has been removed according to the expansion and contraction of the rod 24a, and the detection of the sensor 24. The controller 25 outputs a shutter opening / closing signal to the linear actuator 26 based on the signal. The linear actuators 26 and 26 are disposed on the cavity plates 15 and 16, and rods thereof are connected to the shutters 4 and 4.
[0047]
Therefore, when the laser chamber 1 is positioned and mounted, the side surface of the laser chamber 1 comes into contact with the rod 24a of the sensor 24 and degenerates, so that the sensor 24 is not removed (attached). ), And the controller 25 sends a “shutter open” signal to the linear actuator 26 in accordance with the detection result. As a result, the rod of the linear actuator 26 retracts and moves the shutter 4 to the open position of the laser beam path 18. In this state, the laser beam emission port 13a of the duct 13 is connected to the laser beam path 18, and the laser beam is oscillated while the front box 7 is hermetically sealed.
[0048]
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 24a of the sensor 24 as shown in FIG. The sensor 24 is expanded as indicated by I, and 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 in accordance with the detection result. As a result, the rod of the linear actuator 26 extends and moves the shutter 4 to the closed position of the laser beam path 18 as indicated by an arrow H. Thus, even if the laser chamber 1 is removed, the airtight state of the front box 7 is maintained.
[0049]
【The invention's effect】
As described above, according to the present invention, the optical component of the laser device can be shielded from the outside air not only at the time of laser oscillation but also at the time of maintenance for replacing the window, etc. It can be effectively protected, and the durability of the apparatus can be dramatically improved.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams showing the configuration of an embodiment of an optical component protection apparatus in a laser apparatus according to the present invention.
2 (a) and 2 (b) are cross-sectional views taken along the line AA in FIG. 1 (a), and FIG. 2 (c) is a cross-sectional view taken along the line DD in FIG. 2 (a).
FIGS. 3A and 3B are diagrams showing a modification of the configuration shown in FIGS. 2A and 2B. FIG.
4 (a) and 4 (b) are diagrams corresponding to FIGS. 1 (a) and 1 (b), showing another embodiment in which air shilling is used as an actuator.
FIG. 5 is a diagram corresponding to FIGS. 1 (a) and 1 (b), showing another embodiment using a linear actuator as the 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 beam path

Claims (1)

By mounting the laser chamber so that the laser light inlet provided in the housing containing the optical components constituting the laser device is connected to the laser light exit provided in the laser chamber, In the optical component protection device in the laser device that protects the optical components from the outside air and performs laser oscillation,
A shutter provided on a surface of the duct of the laser chamber to which the laser beam emission port is connected, movably in the direction of removing the laser chamber, and opens and closes the laser beam inlet;
At the time of positioning and mounting of the laser chamber, the laser chamber is moved and positioned at a position where the laser light entrance is opened as the laser chamber is mounted.
An optical component in a laser apparatus, comprising: a shutter that is positioned while maintaining the hermetic state of the housing at a position that is moved to close the laser light inlet according to removal of the laser chamber Protective device.

Images