JP3856497B2 - Gas cleaning apparatus and exposure apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas cleaning apparatus that generates a clean gas containing no contaminants, which is applied in the fields of nuclear power, medical care, semiconductor manufacturing, and the like.
[0002]
[Prior art]
In the nuclear field, clean air free of radioactive contaminants is used. In the medical, pharmaceutical, and bio fields, clean air from which contaminant particles such as bacteria are removed from the atmosphere. In the semiconductor field, contaminated particles and ionic chemical pollutants are present. It is common to use a clean gas that has been removed. In particular, in order to produce a clean gas from which chemical contaminants in the semiconductor manufacturing field have been removed, generally two types of filters are roughly used according to the purpose, and filters for specific substances are commercially available. Yes. In the first type, activated carbon is used as a filter medium, and contaminants are physically adsorbed and removed by a minute hole of the activated carbon. This is suitable for the removal of organic pollutants. The second type uses an ion exchanger as a filter medium, and selectively adsorbs anions and cations on a pollutant existing in the state of ions in air by a substance having ion exchange ability. This is suitable for the removal of alkaline or acidic contaminants.
[0003]
In recent years, chemical contamination of air in a clean room where semiconductor manufacturing is performed has become a problem, and various countermeasures have been taken. In particular, the influence on the imaging performance of the projection exposure apparatus is highlighted. There are two major effects on the projection exposure apparatus. One is the generation of a new substance by a photochemical reaction between exposure light having a short wavelength such as excimer laser light and a substance in the atmosphere such as sulfurous acid. This product adheres to the surfaces of the illumination optical system and the projection optical system and causes fogging. As a result, there is a problem that the amount of transmitted illumination light is reduced, resulting in a decrease in illuminance.
[0004]
The other is a reduction in resolution due to line width instability found in a resist pattern called a T-top. In a projection exposure apparatus for excimer laser light, a chemically amplified photoresist is used. Since this resist has a low light absorptance and a high light transmittance, it has a preferable feature that cannot be obtained by a conventional resist in that the resist cross-sectional shape becomes substantially rectangular after development. However, when an alkaline substance such as ammonia is present on the surface of the resist, the acid that promotes photosensitivity generated by exposure reacts with the alkaline substance to form an insoluble layer on the surface of the chemically amplified photoresist. . For this reason, the cross-sectional shape of the resist after development becomes a substantially “T” shape as shown in FIG. 7, and a resist pattern having a desired line width cannot be obtained. In FIG. 7, reference numeral 120 denotes a silicon wafer, 122 denotes a material to be etched, 124 denotes a developed photoresist, and 126 denotes an insoluble layer.
[0005]
The cause of these two problems is chemical contaminants in the clean room. In order to remove this, an optimum filter is designed and manufactured from the two types of filters according to the main target contaminant and its concentration, and is incorporated into a gas cleaning apparatus, and cleaner air is supplied to the projection exposure apparatus. . This is shown in FIG. In FIG. 8, 110 is a chamber for accommodating the projection exposure apparatus 112, 114 and 116 are filter fan units (FFU) constituting a gas cleaning apparatus, and 118 is a frame for the filter fan unit 116.
[0006]
[Problems to be solved by the invention]
In the conventional technology as described above, the main pollutant as a target can be removed by one type of filter, but other pollutants remain. In addition, since the filter has a relatively short life, the replacement frequency is high and the exposure operation must be stopped each time. That is, there is a problem that an increase in so-called downtime in the exposure apparatus is inevitable. In particular, a filter using activated carbon can itself be a source of dust generation, so that foreign matter such as particles falling from the filter may remain in the gas cleaning device or in the clean room where the exposure device is installed. There is.
[0007]
The present invention has been made in view of such a situation, and an object of the present invention is to provide a gas cleaning device that has a low frequency of filter replacement and a short replacement time. It is another object of the present invention to provide a gas cleaning device that can satisfactorily prevent dust generation by a filter.
[0008]
[Means for solving the problems]
In order to solve the above-described problems, a gas cleaning device of the present invention is provided with a plurality of filters (38, 40, 42) having a filtering member that filters contaminants in the gas and an outer frame member that supports the filtering member. 44); and a cartridge (22) that accommodates the plurality of filters in an overlapping manner with respect to the gas flow, and holds the plurality of filters integrally and exchangeably, and is disposed between the plurality of filters, respectively. A base portion (46b) of the adjusting member; and an airtight sealing material (46a, 64a, 70a) provided between the base portion of the adjusting member and the outer frame member of the filter; and the plurality of filters (38, 40, 42, 44) include filters having different sizes, and the bases (46b) of the adjusting members disposed between the filters having different sizes are different in size from each other. To superimpose the filter, characterized by having a size that the size corresponding to each of the outer frame member of different filters.
[0009]
In the gas purifier as described above, preferably, the pressing members (60, 58a) press the outer frame members (64, 70) of the plurality of filters (38, 40, 42, 44) against the base (46b) side of the adjusting member. , 58b, 58c) are attached to the cartridge (22). Further, a dust generation prevention filter (24, 26) for preventing the scattering of foreign matters generated from the filter (38, 40, 42, 44) is provided on at least one of the intake side and the exhaust side of the cartridge (22). As such a dust prevention filter, the dust prevention filter (68) attached directly to the cartridge (22) so as to block the intake side and the exhaust side of the cartridge (22) can be used.
[0010]
As another aspect of the present invention, a plurality of cartridges (80a, 80b) are arranged in parallel, and a plurality of cartridges (80a, 80b) are used to selectively use the plurality of cartridges (80a, 80b). The flow path switching means (86, 88) for changing with respect to (80a, 80b) is provided.
[0011]
[Action]
In the first aspect of the present invention, an airtight seal material (46a, 64a,) is provided between the base portion (46b) of the adjustment member and the outer frame member (64, 70) of the filter (38, 40, 42, 44). Since 70a) is provided, the gas to be cleaned always passes through the filter members (66, 72) of the filters (38, 40, 42, 44). Moreover, the difference in size of each filter (38, 40, 42, 44) can be absorbed (adjusted) by the base (46b) of the adjusting member, and any commercially available filter can be used.
[0012]
In addition, since the plurality of filters (38, 40, 42, 44) can be replaced at a time by replacing the cartridge (22), the stop time (down time) of the apparatus (exposure apparatus, etc.) to which the purified air should be supplied is reduced. (Time) is shortened, which contributes to the improvement of productivity.
[0013]
According to the invention described in claim 4, the outer frame members (64, 70) of the plurality of filters (38, 40, 42, 44) are adjusted by the pressing members (60, 58a, 58b, 58c). The filter (38, 40, 42, 44) can be securely held in the cartridge (22) by being pressed to the base (46b) side. According to the fifth aspect of the present invention, when the dust prevention filters (24, 26) are provided on the intake side and the exhaust side of the cartridge (22), the cartridge (22) is replaced when the cartridge (22) is replaced. ) The particles (fine particles or dust) inside are not likely to fall or scatter. In particular, if the dust prevention filter (68) is directly attached to the cartridge (22) so as to block the intake side and the exhaust side of the cartridge (22), the old cartridge (22) can be replaced by replacing the cartridge (22). Foreign matter such as existing particles is removed together with the cartridge.
[0014]
Further, when a plurality of cartridges (80a, 80b) are arranged in parallel, the plurality of cartridges (80a, 80b) are selectively selected by changing the gas flow path by the flow path switching means (86, 88). Can be used. As a result, the filter can be replaced only by switching the filter cartridge (80a, 80b), that is, by switching the air flow path, so that the downtime of the apparatus (exposure apparatus or the like) to which the purified air is to be supplied. Is very close to zero.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples. In this embodiment, the present invention is applied to a gas cleaning apparatus for a projection exposure apparatus used for manufacturing a semiconductor device.
[0016]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a gas cleaning apparatus (FFU) according to this embodiment applied to a projection exposure apparatus. Moreover, FIG. 2 shows the detailed structure of the gas cleaning apparatus of a present Example. The gas cleaning apparatus of this embodiment cleans air for air conditioning supplied to the illumination system 14 of the projection exposure apparatus 12 accommodated in the chamber 10, and necessary components are provided outside the chamber 10. It is accommodated in the arranged casing 16. The gas cleaning device (housing 16) is configured to be movable by four casters 18, and can be installed adjacent to the chamber 10, or can be moved to a predetermined place or another room in the clean room. The casing 16 can be fixed to the floor by a fixing jack 56 (see FIG. 2). An operation panel 20 is provided on the top of the housing 16 so that an operator can perform a predetermined operation. In addition, an air intake port 28 is provided at the lower part of the housing 16 so that outside air can be taken into the housing 16. The casing 16 is formed in a square cylinder shape that is open at the top and bottom. In addition, the shape of the housing | casing 16 is not restricted to square cylinder shape, It is also possible to shape | mold in cylindrical shape.
[0017]
A filter cartridge 22 having four chemical filters 38, 40, 42, and 44 (see FIG. 2) is accommodated in a substantially central portion of the housing 16 so as to be able to be taken in and out. A cartridge replacement door (not shown) for inserting and removing the filter cartridge 22 is provided on the front surface of the housing 16. Dust-preventing filters 24 and 26 are provided at the upper and lower portions of the filter cartridge 22 to prevent the particles from falling and scattering from the chemical filters (38, 40, 42, 44). It prevents dust generation due to vibration and impact during replacement. As the dust generation prevention filters 24 and 26, a nonwoven fabric or a ULPA filter can be used.
[0018]
In FIG. 2, three valve mechanisms 30 connected to a hose (not shown) that supplies clean air that has passed through the filter cartridge 22 to the illumination system 14 are provided at the upper part of the housing 16. . Each valve mechanism 30 includes a flow meter 32 that measures the flow rate of air supplied from the gas cleaning device, a ball valve 34, and a connection portion 36 to the hose. An axial fan 54 for forcibly sending air taken in from the gas intake port 28 to the filter cartridge 22 side is disposed below the dust prevention filter 26. The air fed by the axial fan 54 reaches the valve mechanism 30 through the dust prevention filter 26, the filter cartridge 22 and the dust prevention filter 24.
[0019]
Next, the configuration of the filter cartridge 22 will be described with reference to FIG. 3 in addition to FIG. A plurality of different types of chemical filters are accommodated in series in the filter cartridge 22, and spacers 46, 48, 50, 52 are inserted between the filters. The number of filters accommodated in the filter cartridge 22 is not limited to four as in the embodiment, but may be three or five depending on the thickness thereof. The chemical filters 38, 40, 42, 44 are designed so that commercially available ones can be used. Each chemical filter 38, 40, 42, 44 is made by selecting an appropriate filter medium type and thickness according to the type and concentration of the contaminant.
[0020]
The spacers 46, 48, 50, 52 are arranged between the filters 38 and 40, 40 and 42, 42 and 44, respectively. Processing is performed in accordance with the size of the frame (64, 70), and it has a function of maintaining compatibility with commercially available products. That is, even when filters having different specifications are used in combination, the filters are superposed well. The height (thickness) of the spacers 46, 48, 50, and 52 varies depending on the number of filters in the filter cartridge 22 and the thickness of each filter. That is, the combination of the filters (38, 40, 42, 44) in the filter cartridge 22 can be freely designed and selected as long as the height dimension of the filter cartridge 22 permits. Each of the chemical filters 38, 40, 42, and 44 can be a filter that removes a single contaminant, but a composite filter that combines filter media that can remove a plurality of contaminants can also be used.
[0021]
As shown in FIG. 4, the spacer 46 keeps the space between the upper and lower filters (38, 40) in an airtight state. That is, the spacer 46 is in close contact with the outer frame of the chemical filter 38 and the outer frame 70 of the chemical filter 40 so that all air passes only through the filter portions 66 and 72 (filter medium) of both the filters 38 and 40. Designed to. FIG. 4 uses another dust prevention filter 68 fixed to the upper part of the filter cartridge 22 in place of the dust prevention filter 24 (see FIG. 2) arranged at the upper part of the filter cartridge 22. An example is shown. As described above, the dust prevention filter may be directly attached to the upper and lower openings of the filter cartridge 22 or may be disposed outside the filter cartridge 22 as shown in FIG. When the dust prevention filter 68 is provided so as to cover the upper and lower openings of the filter cartridge 22, the foreign matter dropped from the filters 38, 40, 42, 44 is prevented from scattering outside the filter cartridge 22. can do. Thereby, it is possible to prevent dust generation not only in the gas cleaning device but also in the clean room.
[0022]
As shown in FIG. 5, the spacer 46 is formed into a frame shape, and includes a base portion 46 b, a sealing material 46 a applied to the upper surface thereof, and a central hollow portion 46 c. As shown in FIG. 4, the sealing material 46 a of the spacer 46 contacts the lower surface of the outer frame 64 of the filter 38 and contacts the sealing material 70 a formed on the upper surface of the outer frame 70 of the filter 40. As a result, the airtight state between the filter 40 and the filter 38 in the filter cartridge 22 is maintained, and all the air that has passed through the filter part (filter medium) 72 of the filter 40 does not leak to the outside, but the filter part 66 of the filter 38 is completely discharged. Will pass. In FIG. 4, only the relationship between the filters 38 and 40 and the spacer 46 is shown, but the filters 40 and 42 and the spacer 48, and the filters 42 and 44 and the spacer 50 are configured similarly. That is, the filter portions (66, 72) of the respective filters 38, 40, 42, 44 are kept airtight by the spacers 46, 48, 50, 52, respectively. Therefore, the air fed from the axial fan 54 is All pass through the filter part (filter medium) of each filter.
[0023]
As shown in FIGS. 3 and 4, pad plates 60 are disposed on the four corners of the outer frame 64 of the uppermost filter 38 in the filter cartridge 22, and are located at corresponding positions on the upper four corners of the filter cartridge 22. The clamping screws 58a, 58b, 58c, and 58d (not shown) inserted therethrough are pressed downward. That is, the four filters 38, 40, 42, 44 are filtered by applying a pressing force to the outer frame 64 of the filter 38 by the fastening screws 58 a, 58 b, 58 c, 58 d through the four contact plates 60. Fix in the cartridge 22 Vertical holes 62 are formed on both side surfaces of the filter cartridge 22 so that the filter cartridge 22 can be easily pulled out from the housing 16 when the filter cartridge 22 is replaced. In FIG. 3, only the front hole 62 is shown, but a similar hole is also formed on the back surface. Further, in order to facilitate the handling of the filter cartridge 22, other means such as providing a handle may be taken.
[0024]
In the gas purifying apparatus according to the first embodiment described above, since the plurality of filters 38, 40, 42, 44 are provided in series in the cartridge 22, the contamination that has been conventionally left untreated or remained. It becomes possible to remove the substance almost completely. As a result, for example, in a projection exposure apparatus, there is an effect of preventing line width instability of a resist that affects imaging performance and a decrease in illuminance in an illumination system or the like. Further, since the difference in size of each filter 38, 40, 42, 44 is absorbed (adjusted) by the spacers 46, 48, 50, 52, it is easy to use a commercially available filter, and mass production is possible in the production of a gas cleaning device. Is possible. In addition, by preliminarily measuring the type and concentration of contaminants, it is possible to design the life of the filter medium, which is determined in proportion to the thickness, to be the same as that of each filter (38, 40, 42, 44). Thereby, the replacement time of all the filters 38, 40, 42, 44 occurs simultaneously, and all the filters can be used without waste. Furthermore, in this embodiment, since the plurality of filters 38, 40, 42, and 44 can be replaced at a time by the cartridge system, the downtime of the apparatus (exposure apparatus or the like) to which the purified air is to be supplied is shortened. This has the effect of improving productivity.
[0025]
FIG. 6 shows an internal configuration of the gas cleaning apparatus according to the second embodiment of the present invention. In this apparatus, two filter cartridges 80a and 80b are accommodated side by side (in parallel) in a housing 78. Above the housing 78, three hose connecting portions 84 for connecting the purified air that has passed through the filter cartridges 80a and 80b to a gas supply hose (not shown) are provided. Further, a gas intake port 92 for taking outside air into the housing 78 is provided below the front surface of the housing 78. On the bottom surface of the casing 78, four casters 79 that allow the casing 78 to move are provided.
[0026]
The two filter cartridges 80a and 80b have the same configuration as the filter cartridge 22 of the first embodiment shown in FIG. Dust prevention filters 82a and 82b are disposed above the filter cartridges 80a and 80b. Dust generation preventing filters 83a and 83b are also arranged below the filter cartridges 80a and 80b. A slide-type shutter 86 is provided above the filter cartridges 80a and 80b so as to switch which filter cartridge air is to be guided to the hose connecting portion 84. Axial fans 90a and 90b are disposed below the filter cartridges 80a and 80b, respectively, so that air taken in from the gas inlet 92 is forcibly sent to the filter cartridges 80a and 80b. ing. Above the axial fans 90a and 90b, a slide type shutter 88 is provided so as to switch between which of the two filter cartridges 80a and 80b the air is sent to. .
[0027]
In the second embodiment as described above, when the gas is selected to pass through the flow path of the filter cartridge 80a, the flow path of the filter cartridge 80b is closed by the shutters 86 and 88. As a result, the air that has entered through the gas inlet 92 passes through the axial fan 90a, the dust prevention filter 83a, the filter cartridge 80a, and the dust prevention filter 82a, and reaches the clean gas takeout hose via the hose connecting portion 84. . On the other hand, when it is time to replace the filter cartridge 80a, etc., since the unused filter cartridge 80b is used, the shutters 86 and 88 are slid to close the flow path of the filter cartridge 80a. The air that enters from the gas inlet 92 reaches the hose connecting portion 84 through the axial fan 90b, the dust prevention filter 83b, the filter cartridge 80b, and the dust prevention filter 82b.
[0028]
The shutters 86 and 88 are not limited to the slide type, but may be a rotary type, a roll blind type, or a blade type in which a plurality of wings are arranged. Further, the number of filter cartridges is not limited to two, and three or more filter cartridges can be accommodated in one casing 78. Furthermore, the types of filters stored in the filter cartridges do not have to be the same, and different filters can be used in consideration of the type, concentration, and filter life of the contaminants.
[0029]
As described above, according to the present embodiment, since the filter cartridges 80a and 80b are provided in parallel, the filter can be replaced only by switching the filter cartridges 80a and 80b, that is, switching the air flow path. Downtime is very close to zero.
[0030]
As mentioned above, although the Example of this invention was described, this invention is not limited to such an Example, It can change in the range which does not deviate from the summary described in the claim. That is, the gas purifier according to the present invention is not limited to the semiconductor manufacturing field, and can be applied to the nuclear field, the medical / medicine / bio field, or the food field that require a clean gas.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a use state of a gas cleaning apparatus (FFU) according to a first embodiment of the present invention applied to a projection exposure apparatus.
FIG. 2 is a front view (partial cross section) showing an internal configuration of the gas cleaning apparatus according to the first embodiment;
FIG. 3 is a perspective view showing an internal structure of a filter cartridge used in the gas cleaning device of the first embodiment.
FIG. 4 is a cross-sectional view showing a configuration of a main part of the first embodiment.
FIG. 5 is a perspective view showing a configuration of a spacer used in the filter cartridge of the first embodiment.
FIG. 6 is a schematic view showing a configuration of a gas cleaning device according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a conventional problem.
FIG. 8 is a conceptual diagram showing a use state of a conventional gas cleaning device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 12 ... Projection exposure apparatus 14 ... Illumination system 16 ... Case 22 of gas purifier 22, 80a, 80b ... Filter cartridge 24, 26, 68, 82a, 82b, 83a, 83b ... Dust prevention filters 38, 40, 42, 44 ... chemical filters 46, 48, 50, 52 ... spacers 46a, 64a, 70a ... sealing materials 86, 88 ... shutters

Claims (9)

In a gas cleaning device that removes pollutants in gas,
A plurality of filters having a filtering member that filters contaminants in the gas, and an outer frame member that supports the filtering member;
A cartridge that accommodates the plurality of filters in an overlapping manner with respect to the gas flow, and holds the plurality of filters integrally and exchangeably;
A base of an adjustment member respectively disposed between the plurality of filters ;
An airtight seal provided between the base of the adjustment member and the outer frame member of the filter ;
The plurality of filters include filters having different sizes from each other,
The base portion of the adjustment member disposed between the filters having different sizes has a size corresponding to each of the outer frame members of the filters having different sizes in order to overlap the filters having different sizes. Gas purifier. The gas purification apparatus according to claim 1, wherein the airtight sealing material is provided on one surface of a base portion of the adjustment member that contacts an outer frame member of the filter.   3. The gas purifier according to claim 1, wherein each of the plurality of filters has filtering members of different types, and the plurality of contaminants can be removed by the plurality of filters. apparatus. The gas according to any one of claims 1 to 3, further comprising a pressing member that is provided in the cartridge and presses an outer frame member of the plurality of filters against a base side of the adjustment member. Cleaning device. The plurality of filters include a chemical filter and a dust prevention filter,
5. The dust generation filter is disposed on at least one of an intake side and an exhaust side of the cartridge to prevent scattering of foreign matters generated from the chemical filter. 6. The gas purifier according to 1. The gas purifier according to claim 5, wherein the base of the adjusting member and the airtight seal material are disposed between the chemical filter and the dust generation filter.   6. The gas purifier according to claim 5, wherein the dust generation prevention filter is directly attached to the cartridge so as to block an intake side and an exhaust side of the cartridge.   A plurality of the cartridges arranged in parallel, and further comprising a flow path switching means for changing the flow path of the gas with respect to the plurality of cartridges so as to selectively use the plurality of cartridges. The gas cleaning device according to any one of claims 1 to 7. In a projection exposure apparatus used for manufacturing a semiconductor device,
A projection exposure apparatus comprising the gas cleaning device according to any one of claims 1 to 8.

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