JP2003258337A - Cleaning method for cabinet for laser apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method for cabinet for a laser apparatus for cleaning the cabinet for a laser apparatus effectively and thoroughly. <P>SOLUTION: A cleaning method for a cabinet for a laser apparatus with laser light (21) transmitting in the cabinet (is adapted such that the method) comprises; an oxygen added cleaning process (S17) where in the state of optical parts being installed therein cleaning laser light (59) irradiates into the cabinet under the atmosphere of oxygen mixed gas containing oxygen; an optical parts assembling process (S23) for assembling optical parts into the cabinet; a storing process (S24) for storing the cabinet with the inside of the cabinet being is sealed from the atmosphere; and an adsorption member assembling process (S25) for assembling an adsorption member for adsorbing at least one of an organic substance and water into the cabinet; a lamp irradiation process (S50) for irradiating inside of the cabinet by an ultraviolet lamp emitting light with ultraviolet wavelengths; and an oxygen non-added cleaning process (S39) for irradiating the inside of the cabinet with cleaning laser light (59) under a purge gas atmosphere not containing oxygen. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a casing for a laser device.

[0002]

2. Description of the Related Art Conventionally, a cleaning device for irradiating a laser beam to clean an optical component has been known.
No. 0-82856. FIG. 16 shows the cleaning device disclosed in the publication, and a conventional technique will be described below with reference to FIG. In FIG. 16, the cleaning apparatus includes a laser oscillator 101 that oscillates a cleaning laser beam 102 having a wavelength in the ultraviolet region, a housing chamber 103 that houses an optical component 104, and a gas introduction mechanism 105 that supplies a predetermined gas to the housing chamber 103. And a gas exhaust mechanism 106 for exhausting the gas in the accommodation chamber 103.

During cleaning, an optical component 104 is installed in a closed chamber 103, and oxygen gas is introduced from the gas introduction mechanism 105 into the chamber 103 while the gas exhaust mechanism 10 is being used.
It is evacuated by 6. Then, the laser oscillator 10
The cleaning laser light 102 oscillated from 1 is shaped by the beam shaping means 108, and the optical component 1 is passed through the windows 107 and 107.
Irradiate 04. As a result, ozone or oxygen radicals are generated from oxygen, and contaminants such as organic substances attached to the optical component 104 are oxidatively decomposed, exhausted, and cleaned. By performing such cleaning, the transmittance of the optical component 104 is improved and its life is extended.

[0004]

However, the conventional technique disclosed in Japanese Patent Laid-Open No. 2000-82856 has the following problems. FIG. 17 shows a schematic configuration diagram of the excimer laser device 109. The excimer laser device 109 includes a laser chamber 112, a front mirror 115, a band narrowing unit 120 that narrows the band of the laser light 111, and a monitor module 116 that measures the characteristics of the laser light 111. The band-narrowing unit 120 includes a band-narrowing box 121, and an optical component 113 is installed inside the box. The monitor module 116 also includes a monitor box 117,
An optical component 114 is installed inside. Further, the optical path of the laser light 111 is covered with an optical path cover 119 for preventing the laser light 111 from leaking to the outside. Hereinafter, the monitor box 117 that covers the optical path of the laser light 11, the optical path cover 119, and the band-narrowing box 121 are collectively referred to as housings 117, 119, and 121.

The laser light 111 is emitted from the optical components 113 and 11
The surface of No. 4 diffusely reflects or refracts inside, and hits the inner walls of the casings 117, 119, and 121. At this time, contaminants such as organic substances adhere to the inner walls of the casings 117, 119 and 121. Therefore, the housings 117, 119, 1
There is a problem that contaminants attached to the inner wall of 21 cause a chemical reaction to be vaporized and adhere to the optical components 113 and 114 to contaminate them. Moreover, the casings 117, 119, 1
The inner wall of 21 has a larger surface area than the optical components 113 and 114, and the amount of attached contaminants is also large. Therefore, in addition to cleaning the optical components 113 and 114,
It is necessary to remove contaminants from the inner walls of the casings 117, 119 and 121. Furthermore, the casings 117 and 11
Inside the 9, 121, a holder (not shown) for moving or fixing the optical components 113, 114 for optical axis alignment is installed. The holder has a complicated shape and a large surface area, and many contaminants adhere to the surface thereof. Therefore, the holder also needs to be washed.

Further, in the prior art, the object to be cleaned is put in the accommodation chamber 103 and the cleaning laser beam 102 is irradiated. However, the casings 117, 119, and 121 are considerably larger than the optical components 113 and 114, and a huge storage chamber 103 is required to accommodate them. Moreover, the outer walls of the casings 117, 119, 121 are painted for aesthetic purposes, and a sticker or the like is attached to call attention to the method of use. Therefore, if the housing 11
Even if 7, 119 and 121 are placed in the housing chamber 103 and irradiated with laser light, a large amount of organic substances are generated from the outer wall, which may contaminate the inner wall and the internal optical components 113 and 114.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for cleaning a laser device casing that efficiently and thoroughly cleans the laser device casing. I am trying.

[0008]

In order to achieve the above-mentioned object, the present invention provides a method for cleaning a casing for a laser device, through which laser light is transmitted, containing oxygen inside the casing. An oxygen-added cleaning step of irradiating the inside of the housing with cleaning laser light in an oxygen-mixed gas atmosphere without installing optical components is provided. As a result, the cleaning laser light, which is ultraviolet light, and ozone and oxygen radicals generated from oxygen liberate and remove the adhered matter that has not been removed by wiping or ultrasonic cleaning from the inner wall of the housing.

The present invention further comprises an optical component assembling step of incorporating the optical component into the housing after the oxygen addition cleaning step. As a result, since the optical component is incorporated after the casing is cleaned, it is less likely that impurities will be generated from the casing and the optical component will be contaminated.

The present invention further comprises a storage step of sealing and storing a low-reactive purge gas inside the housing after the step of incorporating the optical component. As a result, the cleaned and clean state is maintained and the optical components and the housing are stored, so that it is not necessary to perform recleaning at the time of use.

Further, the present invention comprises an oxygen-free cleaning step of irradiating the inside of the housing with cleaning laser light in an oxygen-free purge gas atmosphere after the optical component assembling step. By irradiating the cleaning laser beam without oxygen, impurities attached to the optical component can be removed without damaging the optical component. At this time, the optical component means an element that is damaged by ozone generated from oxygen. For example, a prism coated with an antireflection film, and other parts such as a grating and a mirror coated with various optical thin films are applicable.

The present invention further comprises a lamp irradiation step of irradiating the inside of the housing with an ultraviolet lamp that emits light having an ultraviolet wavelength after the step of incorporating the optical component. This allows
It is possible to remove impurities attached to the back of an optical component or the like that cannot be completely washed even in the oxygen-free washing step.

Further, according to the present invention, the cleaning laser light is scattered inside the housing by using the scattering optical component in the oxygen-added cleaning step. As a result, the cleaning laser light reaches all corners inside the housing, so that impurities remaining on the inner wall of the housing are extremely reduced.

Further, according to the present invention, at the time of the oxygen-added cleaning step, the amount of at least one of organic matter and water inside the housing is detected, and the cleaning laser light is emitted until the detected value falls within a predetermined allowable range. Irradiating. As a result, impurities can be sufficiently removed, and an appropriate irradiation time that is not too long can be obtained.

The present invention also includes an adsorbent incorporating step of incorporating an adsorbent that adsorbs at least one of an organic substance and moisture into the inside of the housing. As a result, the impurities generated from the housing are adsorbed, so that the impurities do not remain inside the housing and are less likely to adhere to the optical component. Then, it is possible to prevent the impurities generated when the cleaning laser beam is irradiated from reattaching to the housing and the impurities leaching from the housing during storage from adhering to the optical component.

The present invention further comprises an organic substance amount measuring step for measuring the amount of organic substances inside the casing, and when the amount of organic substances does not exceed a predetermined value, an optical component set for assembling optical components inside the casing is provided. After the attaching step and the optical component assembling step, an oxygen-free cleaning step of irradiating the inside of the housing with cleaning laser light in a purge gas atmosphere containing no oxygen is provided. As a result, the impurities inside the housing can be removed by the oxygen-free cleaning process, so that cleaning can be shortened.

Further, in the present invention, in the organic substance amount measuring step, when the amount of organic substance exceeds a predetermined value, an optical component removing step of removing an internal optical component and an oxygen component removing step without the optical component being installed. And an oxygen-added cleaning step of irradiating the inside of the housing with a cleaning laser beam in an oxygen mixed gas atmosphere containing. This makes it possible to reliably remove impurities that could not be removed by the oxygen-free cleaning step.

In the present invention, the organic substance is at least one of a silicon type substance and a sulfur compound. This makes it possible to reliably determine whether or not the organic substance inside can be removed in the oxygen-free cleaning step, and it is possible to perform appropriate cleaning according to the state. In particular, a silicon-based material generates SiO2 and adheres to an optical component when irradiated with a cleaning laser beam even if its amount is very small. Therefore, by preliminarily measuring the amount and setting it to be equal to or less than a predetermined amount inside the housing at the time of irradiation of the cleaning laser light, it is possible to prevent the adhesion to the optical component.

[0019]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a configuration diagram of a general excimer laser device or fluorine molecular laser device. In FIG. 1, a laser device 11 includes a laser chamber 12 that seals a laser gas. A pair of main electrodes 14 and 15 are arranged inside the laser chamber 12 so as to face each other in a direction perpendicular to the paper surface of FIG. 1, and a high voltage power supply (not shown) causes a discharge between the main electrodes 14 and 15,
The laser gas 21 is generated by exciting the laser gas. 1
Reference numerals 7 and 19 denote windows that transmit the laser light 21.

The generated laser beam 21 is incident on the band narrowing box 31 arranged behind the laser chamber 12 (on the left side in FIG. 1) through the entrance 37. Inside the band-narrowing box 31, prisms 32, 32 and a grating 33 are installed. Reference numeral 38 is a holder 38 for holding an optical component. The laser light 21 includes a prism 32,
The beam width is expanded by 32, and the grating 33
The light is diffracted at a predetermined wavelength to narrow the band and reflected in the incident direction. While reciprocating between the front mirror 16 and the grating 33, the light partially passes through the front mirror 16 and is emitted forward.

A monitor box 39 is installed on the optical axis of the emitted laser light 21. Beam splitter 2
2, part of the laser light 21 reflected downward in FIG.
Is reflected by the beam splitter 40 and the reflection mirror 41,
The pulse energy and wavelength characteristics are measured by entering the pulse energy measuring device 42 and the wavelength measuring device 43, respectively. Laser light 21 transmitted through the beam splitter 22
Is reflected by the optical path mirrors 44A and 44B and enters the exposure device 25 such as a stepper. Between the laser chamber 12 and the band-narrowing box 31, between the laser chamber 12 and the monitor box 39, between the monitor box 39 and the exposure unit 25
And the other optical paths through which the laser light 21 passes are
Each is surrounded by optical path covers 45A to 45C.

A purge cylinder 46 containing a clean and low-reactive purge gas is connected to the optical path covers 45A to 45C. From the purge cylinder 46, the optical path cover 45
A purge gas is continuously fed into the A to 45C, the band-narrowing box 31, and the monitor box 39 to expel oxygen and organic substances from the inside. Nitrogen is preferable as the purge gas, but an inert gas such as helium may be used. In the present invention, in such an excimer laser device 11 or a fluorine molecular laser device, the band-narrowing box 31, the monitor box 39, and the optical path covers 45A to 45C are arranged on the inner wall of the casing or inside the casing. A technique for optically cleaning optical components and the like will be described.

In each of the following embodiments, the band narrowing box 31 will be described as an example of the casing to be cleaned, but the monitor box 39 and the optical path cover 45A will be described.
The same applies to other housings such as ~ 45C. When the housing is the monitor box 39, for example, the beam splitter 22 and the beam splitter 4
0, the reflection mirror 41, the pulse energy measuring device 42, the wavelength measuring device 43, etc. correspond to the optical components in the description. When the housing is the optical path covers 45A to 45C, for example, the front mirror 16 or the optical path mirror 4 is used.
4A and 44B correspond to optical components.

First, the first embodiment will be described. In Figure 2,
The cleaning procedure according to the first embodiment is shown in a flowchart. First, the surface of the casing such as the band narrowing box 31 and the structural parts such as the holder 38 holding the optical parts 32 and 33 are wiped clean with pure water and a detergent, and ultrasonically cleaned in pure water. Perform (step S11). This allows
The fine dust adhering to the inner wall surface of the band-narrowing box 31 and the processing oil when manufacturing the band-narrowing box 31 are removed.

Next, while the narrow band box 31 is filled with nitrogen gas, the narrow band box 31 is heated by an oven and dried (step S12).
As a result, the water used during the cleaning in step S11 is removed. Then, only the structural component 38 is assembled to the band narrowing box 31 (step S13). in this way,
Steps S11 to S13 are performed with the inside of the band-narrowing box 31 open to the atmosphere.

Then, the band-narrowing box 31 is attached to the cleaning device 35 (step S14). In FIG. 3, in step S14, the band-narrowing box 31 is set to the cleaning device 35.
The block diagram when attached to is shown. In FIG. 3, the cleaning device 3
5 is a cleaning laser device 36 that oscillates a cleaning laser light 59.
Is equipped with. As the cleaning laser device 36, an excimer laser device or a fluorine molecular laser device that generates ultraviolet laser light is suitable. At this time, the cleaning laser device 3
6 does not need to narrow the wavelength band, so that, for example, in FIG.
In the excimer laser device or the fluorine molecular laser device shown in FIG. 3, it is preferable that only the pulse energy measuring device 42 is installed in the monitor box 39 and the total reflection mirror 41 is provided in place of the band narrowing box 31. is there.

Cleaning laser device 36 and band narrowing box 3
The space between 1 and 1 is surrounded by a cleaning cover 48,
Nitrogen gas is continuously supplied to the inside. A gate valve 47 that can be manually opened and closed is provided at the entrance 37 of the band-narrowing box 31. When the gate valve 47 is opened, the cleaning laser light 59 is emitted from the opening (not shown),
It can be made incident into the narrow band box 31.
Further, an O-ring (not shown) is incorporated in the gate valve 47, and when the gate valve 47 is closed, the inside of the band narrowing box 31 is sealed. The cleaning laser light 59 emitted from the cleaning laser device 36 enters the narrow band box 31 to be cleaned from the entrance 37. An organic substance detector 52 that detects the amount of organic substances inside, a moisture detector 53 that detects the amount of moisture, and an oxygen concentration detector 54 that detects the oxygen concentration inside are connected to the band-narrowing box 31. There is. Further, in the band-narrowing box 31, a vacuum pump 49 for exhausting the gas inside,
An oxygen mixing cylinder 51, which is filled with an oxygen mixing gas in which nitrogen is mixed with oxygen at a predetermined ratio, and a nitrogen cylinder 50 are connected.

As shown in FIG. 3, the band-narrowing box 3
1 mounted on the cleaning device 35, the gate valve 47
Is opened, and nitrogen is continuously supplied from the nitrogen gas cylinder into the band-narrowing box 31 (step S15). Thus, the impurities mixed in the air inside the band-narrowing box 31 are removed before the band-narrowing box 31 is attached to the cleaning device 35 in step S14. Alternatively, at this time, if the process of exhausting the inside of the band-narrowing box 31 with the vacuum pump 49 and filling it with nitrogen is repeated, the impurities can be more thoroughly removed.

Then, based on the outputs of the organic substance detector 52 and the moisture detector 53, the amount or concentration of the organic substance, moisture, and oxygen in the band-narrowing box 31 is detected, and the amount or concentration of these impurities is within an allowable range. Whether or not it is determined (step S16). At this time, as the organic matter, siloxane, which is a silicon-based substance, and a sulfur compound are detected. In particular, when the cleaning laser light 59 is applied to the silicon-based material, Si is decomposed and is combined with oxygen emitted from other organic substances and water to generate SiO2. This SiO2
Has a harmful effect on the surface of the optical component such as a white powder even if the amount is very small, and changes the refractive index of the optical component. Therefore, carefully remove it before irradiating the cleaning laser beam 59. It is necessary to leave.

In step S16, if even one item out of the concentrations of organic matter and moisture is outside the allowable range, the process returns to step S15 and the nitrogen supply is continued. If all the items are within the permissible range, an oxygen mixed gas of nitrogen and oxygen is supplied to the inside of the band-narrowing box 31, and the cleaning laser beam 59 is applied to the inside of the band-narrowing box 31 (step S17). . At this time, the oxygen concentration detector 54
By detecting the concentration of oxygen in the narrow band box 31, for example, by simultaneously supplying nitrogen from the nitrogen cylinder 50,
It is necessary to control the gas so that the oxygen concentration becomes a predetermined concentration. That is, as the cleaning laser beam 59, KrF or A
When rF excimer laser light is used, the concentration of oxygen may be high, for example, about 20%. However, when vacuum ultraviolet laser light such as fluorine molecular laser light is used as the cleaning laser light 59, it is necessary to suppress the concentration of oxygen to about 1000 ppm or less in order to prevent the cleaning laser light 59 from being absorbed by oxygen. There is.

Inside the band-narrowing box 31, a scattering optical component 55 for scattering the cleaning laser light 59 is installed. The cleaning laser light 59 hits the scattering optical component 55, is scattered on the surface thereof, and is applied to the entire inner wall of the band-narrowing box 31. As a result, the cleaning laser light 59, which is ultraviolet light, and the ozone and oxygen radicals generated from oxygen release the deposits not removed during cleaning in step S11 from the inner wall of the band-narrowing box 31 and the holder. The scattering optical component 55 may not be a reflection type as shown, but may be one that transmits the cleaning laser light 59 and scatters like a diffusion plate.

Then, while irradiating the cleaning laser beam 59, the moisture detector 53 detects the amount of moisture in the band-narrowing box 31, and the irradiation is continued until it falls within the allowable range (step S18). If the amount of water falls within the allowable range, the cleaning laser beam 59 is stopped (step S19), the gate valve 47 is closed to evacuate the inside of the band-narrowing box 31, and then the inside is filled with nitrogen (step S2).
0). Then, the organic substance detector 52 measures the amount of organic substances in the band-narrowing box 31 to determine whether or not this is within the allowable range (step S21). Step S21
If the value is outside the allowable range in step S17, the process returns to step S17, oxygen is supplied again, and the cleaning laser beam 59 is irradiated again. Step S
21, if it is within the allowable range, the cleaning laser beam 59 is stopped, the gate valve 47 is closed, and the band narrowing box 31
Is sealed and removed from the cleaning device 35 (step S22).

In step S18, only the amount of water is used to determine whether or not to stop the cleaning laser beam 59. Ozone is generated inside the cleaning laser beam 59 during irradiation, and the oxygen detector and the organic substance are not generated. This is because the detection by the detector 52 cannot be performed accurately. Therefore, in this flowchart, in steps S20 and S21, the inside of the band-narrowing box 31 is evacuated to seal nitrogen,
The amount of organic substances is detected to make sure that impurities do not remain inside. However, step S
Instead of performing steps 20 and S21, the cleaning process using the cleaning laser beam 59 may be ended using only the water content in step S18 as a criterion for determination.

Then, the band-narrowing box 31 is brought into a clean space such as a clean room, the gate valve 47 is removed and the holder 38 inside the band-narrowing box 31 is provided with a grating 33 and prisms 32, 32.
Assemble the optical parts 32 and 33 such as (step S2
3). Then, the entrance 37 is closed by a plate or the like instead of the gate valve 47, the inside of the band-narrowing box 31 is evacuated, and stored in a state of being filled with nitrogen (step S24). Alternatively, in step S24, the entrance 3
Alternatively, the band narrowing box 31 may be placed in a storage chamber in which the inside can be evacuated and filled with nitrogen with 7 opened, and the storage chamber may be stored with the interior of the storage chamber filled with nitrogen.

As described above, according to the first embodiment, a cleaning laser which is an ultraviolet ray is applied to the inner wall of the casing 31 and the structural parts 38 by introducing an oxygen mixed gas containing oxygen into the casing 31. The light 59 is emitted. As a result, the cleaning laser light 59 causes the inner wall of the housing 31 and the structural parts 38
In addition to releasing organic substances and water adhering to, organic substances and the like are also oxidatively decomposed and released by ozone and oxygen radicals generated from oxygen. Therefore, by exhausting the inside of the casing 31, the liberated impurities can be removed, and the inner wall of the casing 31 and the structural component 38 can be cleaned more cleanly.

In particular, when the cleaning laser light 59 is ArF excimer laser light, the cleaning is performed in a state where oxygen is added, so that organic substances that were not decomposed in a state where oxygen is not added are preferably decomposed. It is possible. 4 to 6 are graphs showing decomposition results of organic substances when ArF excimer laser light is used as the cleaning laser light 59. 4 to 6, the horizontal axis represents the irradiation time of the cleaning laser light 59, and the vertical axis represents the residual amounts of n-hexane, toluene, and siloxane, respectively. In FIGS. 4 to 6, when the broken line is nitrogen without addition of oxygen,
The solid line shows the case where 20% of oxygen is added to nitrogen. Figure 4-
As shown in FIG. 6, by adding oxygen, a great effect is exhibited as compared with the case where only nitrogen is not added.

Also, when the fluorine molecular laser beam is used as the cleaning laser beam 59, the effect of oxygen addition appears in the experimental results. Some substances, such as toluene, are relatively slow to decompose even when irradiated with a fluorine molecular laser beam having a shorter wavelength than the ArF excimer laser beam. FIG. 7 is a graph showing the result of decomposition of organic substances when fluorine molecular laser light is used as the cleaning laser light 59. In FIG. 7, the horizontal axis represents the irradiation time of the cleaning laser light 59, and the vertical axis represents the residual amount of toluene. In FIG. 7, the broken line shows the case where oxygen is not added, and the solid line shows the case where oxygen is added at 1000 ppm.
As shown in FIG. 7, by adding oxygen, it becomes possible to decompose toluene, which would otherwise be slow to decompose.

The cleaning according to the first embodiment is a casing of the laser device 11 in which the presence of organic substances does not significantly affect the pulse energy and the wavelength of the laser light 21, such as a KrF excimer laser device. It is good to do it for the body 31. That is, according to the first embodiment, the optical components 32 and 33 are not cleaned, and the optical components 32 and 33 are assembled inside the housing 31 in the atmosphere after cleaning. Moisture may remain inside the housing 31. Further, in order to enable such cleaning, the optical component 31 needs to be manufactured and stored in a very clean state before assembly. When such a condition is satisfied, the first embodiment has an advantage that the cleaning work is relatively easy as compared with the respective embodiments described below.

Next, a second embodiment will be described. In FIG.
A cleaning procedure according to the second embodiment is shown in a flowchart. Steps S11 to S23 are the same as those in the first embodiment, and description thereof will be omitted. Then, after the optical components 32 and 33 are assembled to the holder 38 in step S23, an adsorbent such as molecular sieve (or molecular sieves) is installed inside the housing 31 (step S25). Then, the entrance 37 is closed by a plate or the like instead of the gate valve 47, the inside of the band-narrowing box 31 is evacuated, and stored in a state of being filled with nitrogen (step S2).
4).

As described above, according to the second embodiment, after the cleaning, the adsorbent that adsorbs water and organic substances is used as the casing 3.
The housing 31 is installed inside the housing 1, and the housing 31 is stored in that state. That is, after cleaning, in step S23, the optical components 32 and 33 are assembled in a state where the inside of the housing 31 is opened to a clean atmosphere. At this time, impurities may be mixed into the inside of the casing 31 and left from the air, or impurities that have not been washed out may exude from the inner wall of the casing 31. In such a case, the molecular sieve can adsorb these impurities and prevent the optical components 32 and 33 from being soiled. What kind of substance should be adsorbed?
It can be determined by selecting the type of molecular sieve.

Next, a third embodiment will be described.
FIG. 9 is a flowchart showing the cleaning procedure according to the third embodiment. Steps S11 to S22 are the same as those in the first embodiment, and description thereof will be omitted. First, step S22
The band-narrowing box 31 removed from the cleaning device 35 in the state of being sealed with is placed on the table 60 inside the glove box 56 (step S31). FIG. 10 shows an explanatory diagram of the glove box 56. In FIG. 10, for example, at least one side surface of the glove box 56 is formed of a transparent wall such as glass or acrylic resin,
The worker wears gloves 57, 57 provided on the transparent side surface.
It is possible to access the internal band-narrowing box 31 via. In addition, the glove box 56,
A glove box cylinder 58 for introducing a purge gas such as clean nitrogen is connected to the inside thereof. Further, the glove box 56 is additionally provided with an oxygen concentration detector 54 and a moisture detector 53, which can measure the amounts of oxygen and moisture therein.

Such a purge gas is supplied to the inside of the glove box 56 (step S32), the oxygen concentration detector 54 and the moisture detector 53 detect the oxygen concentration and the amount of moisture in the glove box 56, and this is determined. It is determined whether or not it is within the allowable range (step S33). Then, when the oxygen concentration and the water content are within the allowable ranges, for example, the upper lid of the band-narrowing box 31 is opened via the gloves 57, 57, and the molecular sieve (not shown) and the optical components 32, 33 are band-narrowed by the box. 31 is assembled (step S34). At this time, the molecular sieve and the optical components 32 and 33 may be carried in at the same time when the band-narrowing box 31 is placed inside the glove box 56 in step S31, or may be placed inside the glove box 56 in advance. You can leave it.

When the assembling is completed, the narrow band box 3
The gate valve 47 of No. 1 is closed to seal the band-narrowing box 31 (step S35), and the band-narrowing box 31 is attached to the cleaning device 35 (step S36). Then, the gate valve 47 is opened to supply the purge gas from the purge cylinder 46 into the narrow band box 31 (step S3).
7). It is confirmed by the oxygen concentration detector 54 and the moisture detector 53 attached to the narrowing band box 31 that the oxygen concentration and the water content inside the narrowing band box 31 are within the permissible range (step S38), and the cleaning is performed. The laser beam 59 is emitted (step S39). Oxygen narrowing box 3
If it remains inside 1, the ozone may be generated by the irradiation of the cleaning laser light 59, and the coating on the surfaces of the optical components 32 and 33 may be contaminated.
Then make sure that almost no oxygen remains.

FIG. 11 shows a configuration diagram when the band-narrowing box 31 is attached to the cleaning device 35 and the cleaning laser beam 59 is irradiated in step S39. Cleaning laser light 59
Like the laser light 21, the light is expanded by the prisms 32 and 32 and is incident on the grating 33. This allows
Impurities such as organic substances and water are released from the surfaces of the prisms 32, 32 and the grating 33 which are irradiated with the cleaning laser light 59. In FIG. 11, the cleaning laser beam 59
A diffusion plate (not shown) is arranged in the optical path of the cleaning laser beam 59.
It is preferable to clean the portions of the optical components 32 and 33 that the cleaning laser light 59 does not pass through by diffusing. Then, the water content detector 53 determines whether or not the water content inside the band-narrowing box 31 has become a predetermined value or less (step S38), and when the water content is within the allowable range, the cleaning laser beam 59 is stopped. Yes (step S40).

After that, the gate valve 47 is closed to evacuate the inside of the band-narrowing box 31, and then the inside is filled with nitrogen (step S42). And the organic matter detector 5
2, the amount of the organic matter in the band-narrowing box 31 is measured, and it is determined whether or not this is within the allowable range (step S
43). If it is out of the allowable range in step S43, the process returns to step S39, and the cleaning laser beam 59 is irradiated again. If it is within the allowable range in step S43, the cleaning laser light 59
Stop, the gate valve 47 is closed, and the band-narrowing box 31 is sealed and removed from the cleaning device 35.
It is stored as it is (step S44).

As described above, according to the third embodiment, oxygen is added to the cleaning laser beam 59 in step S17.
Of the optical component 3 in the band-narrowing box 31 inside the glove box 56 filled with the purge gas.
2, 33 are assembled. As a result, when the band-narrowing box 31 is opened, air is extremely unlikely to be mixed into the band-narrowing box 31, so that moisture, organic substances, and the like can be removed from the inner wall of the band-narrowing box 31 and the holder 38. It is less likely to adhere, and the optical components 32 and 33 are less likely to be soiled. At this time, the molecular sieve is assembled inside the band-narrowing box 31. As a result, impurities are released from the inner wall or the holder 38 by the cleaning laser light 59 in step S39, or in step S39.
Even when impurities that cannot be completely removed by 17 are gradually released, they can be reliably captured and the optical components 32 and 33 can be prevented from being contaminated.

Further, after the cleaning laser beam 59 is irradiated in the oxygen-added state, the optical parts 32 and 33 are assembled, oxygen is not added, and the cleaning laser beam 59 is irradiated again.
The surface coating of the optical components 32 and 33 may be contaminated by ozone. Therefore, by irradiating the cleaning laser beam 59 in a gas containing no oxygen,
Effective cleaning with ultraviolet light is possible without contaminating the optical components 32 and 33.

Next, a fourth embodiment will be described.
FIG. 12 is a flowchart showing the cleaning procedure according to the fourth embodiment. Steps S11 to S34 are the same as in the third embodiment, and description thereof will be omitted. And step S
At 34, after opening the upper lid of the band-narrowing box 31 and assembling the molecular sieve and the optical components 32 and 33 into the band-narrowing box 31, inside the glove box 56,
The inside of the band-narrowing box 31 is irradiated with a xenon (Xe) lamp (step S50). FIG. 13 shows a xenon lamp 61 which can be irradiated with the xenon lamp 61.
The block diagram of the attached glove box 56 is shown. As shown in FIG. 13, a xenon lamp 61 that is movable in the height direction is suspended from the ceiling of the glove box 56. When irradiating, the xenon lamp 61 is lowered and turned on via a globe (not shown), and the optical components 32, 3
The band-narrowing box 31 in which 3 is assembled is irradiated from above with the upper lid open.

That is, in the case of an optical component such as the grating 33 which does not transmit the cleaning laser light 59, the cleaning laser light 59 does not reach the back surface of the grating 33 when the cleaning laser light 59 is irradiated, and the back surface is not irradiated. There may be insufficient cleaning. In order to compensate for this, in the present embodiment, the xenon lamp 61 is irradiated onto the optical components 32 and 33, and the portion that cannot be completely washed by the washing laser light 59 alone is washed. As a result, like the cleaning laser beam 59,
Impurities such as organic matter and water can be released.

The irradiation of the xenon lamp 61 is determined by the moisture detector 53 attached to the glove box 56 to determine whether or not the amount of moisture is within the allowable range (step S51), and the irradiation may be performed until it falls within the allowable range. Alternatively, a predetermined irradiation time may be set. Then, the upper lid of the band-narrowing box 31 is closed and the gate valve 47 is closed to seal the band-narrowing box 31 (step S35). The following steps S36 to S44 are the same as those in the third embodiment, and description thereof will be omitted.

As described above, according to the fourth embodiment, the optical components 32 and 33 are irradiated with the xenon lamp 61. As a result, ultraviolet rays are radiated to the parts of the optical components 32 and 33 that the cleaning laser beam 59 does not reach, and more thorough cleaning is performed. Also, the xenon lamp 61
The wavelength of the ultraviolet light emitted from 172 nm is KrF.
It has a shorter wavelength than the excimer laser light (248 nm) and the ArF excimer laser light (193 nm). Therefore, the cleaning ability of decomposing and releasing the organic substance becomes stronger. In the above flowchart, the xenon lamp 61 is irradiated with the optical components 32 and 33 assembled, but the optical components 32 and 33 before assembly are used, for example.
Alternatively, the xenon lamp 61 may be irradiated beforehand. As a result, the cleaning of the optical components 32 and 33 can be performed more thoroughly, and the adhesion of impurities is further reduced. Note that the present embodiment is not limited to the xenon lamp 61, and any lamp having a similar ultraviolet wavelength may be used.

FIG. 14 shows a cleaning procedure in which the timing of incorporating the molecular sieve is changed in the flowchart shown in FIG. In FIG. 14, there are four possible timings for assembling the molecular sieve inside the band-narrowing box 31: A1 to A4. As a first example, as shown by the arrow A1, in step S13, the molecular sieve is attached after the structural component 38 is attached to the band-narrowing box 31. This allows impurities adhering to the inside of the band-narrowing box 31 to be adsorbed and removed in advance from the initial state, so that the cleaning laser beam 59 can be irradiated in a relatively clean state, for example, the irradiation time of the cleaning laser beam 59. Becomes shorter. Further, it is unlikely that the impurities are saturated inside the band-narrowing box 31 and are not released any more, and the impurities can be reliably removed.

As a second example, as shown by an arrow A2, a molecular sieve is assembled inside the band-narrowing box 31 immediately before the irradiation of the cleaning laser beam 59 in the oxygen-added state in step S17. As a result, impurities such as organic substances and water released upon irradiation with the cleaning laser light 59 can be adsorbed, and thus impurities may reattach to the inner wall of the housing 31 immediately after the irradiation with the cleaning laser light 59 is stopped. A small amount, and reliable removal is possible.
As a third example, as shown in the flowchart of FIG. 12 (arrow A3), a molecular sieve may be incorporated together with the optical components 32 and 33 in step S34. As a fourth example, as shown by arrow A4,
Immediately before sealing the band-narrowing box 31 in step S35, a molecular sieve may be incorporated. As a result, in step S39, the band-narrowing box 31
Impurities generated when the cleaning laser beam 59 is irradiated in the oxygen-free state can be adsorbed by the molecular sieve.
As a result, the impurities are unlikely to reattach to the inner wall immediately after the irradiation of the cleaning laser beam 59 is stopped, and the reliable removal is possible.

In the above-described embodiment, the cleaning laser device 36 is common for the case of adding oxygen and the case of not adding oxygen, but the present invention is not limited to this. For example, in the case where oxygen is added to the interior of the housing 31 and the structural component 38 to irradiate the cleaning laser light 59 as in step S17, the same as the laser light 21 oscillated from the laser device 11 using the housing 31. Alternatively, it is preferable to use the cleaning laser device 36 that oscillates the cleaning laser light 59 having a shorter wavelength. That is, the shorter the wavelength of the cleaning laser light 59 is, the larger the energy thereof is. Therefore, by using the cleaning laser light 59 having a short wavelength, more thorough cleaning can be performed. On the other hand, if the cleaning laser light 59 having a long wavelength is used,
When the casing 31 and the structural component 38 are assembled to the laser device 11 and irradiated with the laser light 21, organic substances and the like that are not liberated by the cleaning laser light 59 are liberated by the larger energy of the laser light 21, and the optical component 32 is released. , 33 may be attached.

On the other hand, as in step S39, the optical components 32 and 33 are assembled and the cleaning laser beam 59 is added without adding oxygen.
In the case of irradiating the laser beam, it is preferable to use the same cleaning laser device 36 as the type of the laser device 11 that uses the optical components 32 and 33. That is, when the cleaning laser light 59 having a wavelength shorter than that of the laser light 21 is used, the energy of the cleaning laser light 59 is too large, which may damage the coating on the surfaces of the optical components 32 and 33. On the other hand, when the cleaning laser light 59 having a wavelength longer than that of the laser light 21 is used, the energy of the cleaning laser light 59 may be too small to perform sufficient cleaning.

FIG. 15 is a flowchart showing the cleaning procedure according to the fifth embodiment. The fifth embodiment will particularly describe the housing 31 and the optical components 32 and 33 used in the fluorine molecular laser device. As described above, the housing 31 and the optical component 3 used for the fluorine molecular laser device 11.
For 2, 33, a fluorine molecular laser device is used as the cleaning laser light 59. Since the fluorine molecular laser beam has a short wavelength, the cleaning power is very strong, and most of the organic substances adhering to the inner wall of the casing 31 are removed except for the silicon-based substance and the sulfur compound, even if oxygen is not added. It is possible. Therefore, in the present embodiment, when the silicon-based material and the sulfur compound are scarcely present inside the housing 31, the cleaning laser beam 59 is irradiated without adding oxygen and only cleaning is performed. .

Steps S11 to S13 are the same as those in each of the above-mentioned embodiments, and the description thereof will be omitted. Then, the optical components 32 and 33 and the molecular sieve are assembled to the band-narrowing box 31 to which the structural component 38 is assembled in step S13 (step S61), and the band-narrowing box 31 is attached to the cleaning device 35 (step S6).
2). Then, the gate valve 47 is opened and nitrogen is continuously supplied into the band-narrowing box 31 from the nitrogen gas cylinder (step S63). As a result, the impurities mixed in the air contained in the band-narrowing box 31 are removed. Then, based on the outputs of the organic substance detector 52 and the moisture detector 53, the amount or concentration of the organic substance, moisture, and oxygen inside the band-narrowing box 31 is detected, and by the predetermined time (step S64), these impurities are detected. It is determined whether or not it is within the allowable range (step S65). At this time, as the organic substance, siloxane, which is a silicon-based substance, and a sulfur compound are detected particularly precisely.
The reason for this is the same as in step S16.

Then, as described above, when the silicon-based material and the sulfur compound are not detected inside the band-narrowing box 31 in step S65, the cleaning laser beam 59 is irradiated with no oxygen (step S65). S6
6). Then, within a predetermined time or within a predetermined number of oscillation pulses (step S67), the amount of water in the band-narrowing box 31,
Irradiation is continued until the oxygen concentration and the organic substance concentration are within the allowable range (step S68). The organic substances in step S67 are aromatic compounds such as toluene and polymer compounds such as n-hexane. When the impurities are within the allowable range, the gate valve 47 is closed to close the band narrowing box 31.
Is removed from the cleaning device 35 (step S69) and stored (step S70).

On the other hand, in steps S65 and S67,
If the impurities do not fall within the permissible range even after the lapse of a predetermined time, only irradiation with the cleaning laser beam 59 without oxygen addition
Determined that complete cleaning cannot be performed. Then, the band-narrowing box 31 is removed from the cleaning device 35, and the internal optical components 32 and 33 are removed from the holder 38 (step S
71). Then, the band-narrowing box 31 in which the optical components 32 and 33 are not arranged is attached to the cleaning device 35 (step S72), the gate valve 47 is opened, and nitrogen is supplied into the band-narrowing box 31 (step S73). . The supply of nitrogen is continued until the internal impurities are within the allowable range (step S74). Then, for example, the process proceeds to step S17 in FIG. 12, and inside the band-narrowing box 31,
An oxygen mixed gas composed of nitrogen and oxygen is supplied to irradiate the cleaning laser light 59 into the narrow band box 31. The following steps are similar to those shown in FIG. At this time, as described in other embodiments, the cleaning with the xenon lamp 61 (step S50) and the use of the glove box 56 (step S31) may be omitted.

As described above, according to the fifth embodiment, the cleaning laser in the oxygen-added state is used only when the silicon-based substance and the sulfur compound are not found in the cleaning of the casing 31 used in the fluorine molecular laser device. Irradiation of the light 59 is omitted. This shortens the cleaning process. In the description of each of the above embodiments, the cleaning laser light 59
Nitrogen has been exemplified as the gas sealed in the housing at the time of irradiation, but an inert gas such as helium may be used.

[Brief description of drawings]

FIG. 1 is a block diagram of a general excimer laser device or fluorine molecular laser device.

FIG. 2 is a flowchart showing a cleaning procedure according to the first embodiment.

FIG. 3 is a configuration diagram of a cleaning device equipped with a band-narrowing box.

FIG. 4 is a graph showing the results of decomposition of organic substances by ArF excimer laser light.

FIG. 5 is a graph showing the result of decomposition of organic matter by ArF excimer laser light.

FIG. 6 is a graph showing the results of decomposition of organic substances by ArF excimer laser light.

FIG. 7 is a graph showing the result of decomposition of organic matter by a molecular fluorine laser beam.

FIG. 8 is a flowchart showing a cleaning procedure according to the second embodiment.

FIG. 9 is a flowchart showing a cleaning procedure according to the third embodiment.

FIG. 10 is an explanatory diagram of a glove box.

FIG. 11 is a configuration diagram of a cleaning device equipped with a band-narrowing box.

FIG. 12 is a flowchart showing a cleaning procedure according to the fourth embodiment.

FIG. 13 is a configuration diagram of a glove box with a xenon lamp.

FIG. 14 is a flowchart of a cleaning procedure in which the timing of incorporating the molecular sieve is changed.

FIG. 15 is a flowchart showing a cleaning procedure according to the fifth embodiment.

FIG. 16 is a configuration diagram of an optical component cleaning device according to a conventional technique.

FIG. 17 is a schematic configuration diagram of an excimer laser device.

[Explanation of symbols]

11: Excimer laser device, 12: Laser chamber, 1
4: main electrode, 15: main electrode, 16: front mirror, 1
7: Front window, 19: Rear window, 2
1: laser light, 22: beam splitter, 25: exposure device, 31: narrow band box, 32: prism, 33:
Grating, 35: Cleaning device, 36: Cleaning laser device, 37: Entrance, 38: Holder, 39: Monitor box, 40: Beam splitter, 41: Reflection mirror, 4
2: pulse energy measuring device, 43: wavelength measuring device,
44: Optical path mirror, 45: Optical path cover, 46: Purge cylinder, 47: Gate valve, 48: Wash cover, 49:
Vacuum pump, 50: Nitrogen cylinder, 51: Oxygen mixed cylinder, 52: Organic matter detector, 53: Moisture detector, 54: Oxygen concentration detector, 55: Scattering optical component, 56: Glove box, 57: Globe, 58: Glove box cylinder, 59: cleaning laser light, 60: table, 61: xenon lamp.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akira Sumitani             1200 Manda, Hiratsuka-shi, Kanagawa Made by Komatsu Ltd.             Seisakusho Institute (72) Inventor Ikuo Uchino             1200 Manda, Hiratsuka-shi, Kanagawa Made by Komatsu Ltd.             Seisakusho Institute (72) Inventor Taketo Watanabe             1200 Manda, Hiratsuka-shi, Kanagawa Made by Komatsu Ltd.             Seisakusho Institute (72) Inventor Osamu Wakabayashi             1200 Gigaphoton Co., Ltd. Manda 1200, Hiratsuka City, Kanagawa Prefecture             Inside the company F-term (reference) 3B116 AA26 AB53 BC01                 5F072 AA04 AA06 JJ20 KK07 KK15                       KK18 KK21 RR05 SS06

Claims (11)

[Claims] 1. A method for cleaning a casing (31, 39, 45) for a laser device, through which a laser beam (21) is transmitted, wherein an oxygen mixed gas atmosphere containing oxygen is contained inside the casing (31, 39, 45). And the cleaning laser light without the optical parts (32, 33) installed.
Oxygen-added cleaning process of irradiating (59) inside the casing (31, 39, 45)
(S17) is provided for the laser device housing (31,3
9,45) cleaning method. 2. The laser device casing according to claim 1,
In the cleaning method of (39, 45), after the oxygen-added cleaning step (S17), an optical component assembling step (S23) for incorporating the optical component (32, 33) into the housing (31, 39, 45) is provided. A method for cleaning a casing (31, 39, 45) for a laser device characterized by the above. 3. The laser device casing according to claim 2,
In the cleaning method of (39, 45), after the optical component assembling step (S23), a storage step of sealing and storing a low-reactive purge gas inside the housing (31, 39, 45)
Laser device housing characterized by having (S24) (31,3
9,45) cleaning method. 4. The cleaning method for a casing (31, 39, 45) for a laser device according to claim 1, wherein the purge gas containing no oxygen is included after the optical component assembling step (S23). Laser light cleaning in atmosphere (59)
Irradiating the inside of the housing (31, 39, 45) with oxygen-free cleaning process (S
39) laser device housing (31, 39,
45) Cleaning method. 5. The laser device casing according to claim 4,
In the cleaning method of (39, 45), after the optical component assembling step (S23), an ultraviolet lamp that emits light of an ultraviolet wavelength is attached to the casing (31, 39,
5) A method for cleaning a casing (31, 39, 45) for a laser device, which comprises a lamp irradiation step (S50) of irradiating the inside. 6. The method for cleaning a laser device casing (31, 39, 45) according to claim 1, wherein a scattering optical component (55) is used during the oxygen-added cleaning step (S17). )
A method for cleaning a casing (31, 39, 45) for a laser device, characterized in that the cleaning laser light (59) is scattered inside the casing (31, 39, 45) by using. 7. The method for cleaning a casing (31, 39, 45) for a laser device according to claim 1, wherein the oxygen-added cleaning step (S17) or the oxygen-free cleaning step (S3) is performed.
At the time of 9), detect the amount of at least one of the organic substances and moisture inside the casing (31, 39, 45), and irradiate the cleaning laser beam (59) until the detected value falls within the predetermined allowable range. A method for cleaning a casing (31, 39, 45) for a laser device, the method comprising: 8. The method for cleaning a casing (31, 39, 45) for a laser device according to claim 1, wherein the casing is made of an adsorbent that adsorbs at least one of organic matter and moisture. (31, 39, 45) Adsorbent assembly step (S25) incorporated into the inside of the laser device housing (3
1,39,45) cleaning method. 9. A method for cleaning a casing (31, 39, 45) for a laser device, through which a fluorine molecular laser beam (21) passes, for measuring the amount of organic substances inside the casing (31, 39, 45). If the amount of organic substances does not exceed the specified value, the optical components (32, 33) are assembled inside the housing (31, 39, 45). 33) Assembling step (S61), and after the optical component assembling step (S61), the inside of the housing (31, 39, 45) is made a purge gas atmosphere containing no oxygen, and the cleaning laser light (59) is used as the housing. (31, 39, 45) A method for cleaning a casing (31, 39, 45) for a laser device, which comprises an oxygen-free cleaning step (S66) of irradiating the inside. 10. The laser device casing according to claim 9,
In the cleaning method of 1,39,45), in the organic matter amount measuring step (S65), when the amount of organic matter exceeds a predetermined value, optical components (32, 39, 45) inside the casing (31, 39, 45) , 33) to remove the optical components (S71), and the inside of the casing (31, 39, 45) is filled with an oxygen-containing gas atmosphere containing oxygen, and the cleaning laser light is used without the optical components (32, 33) being installed. Case for laser device characterized by comprising an oxygen-added cleaning step (S17) of irradiating the inside of the case (31, 39, 45) with (59)
How to wash (31, 39, 45). 11. The method for cleaning a casing (31, 39, 45) for a laser device according to claim 9, wherein the organic substance is at least one of a silicon-based substance and a sulfur compound. Laser device housing (3
1,39,45) cleaning method.