JP2000140543A - Air filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air filter device in which airtightness between a filter medium and a frame material holding the filter medium is secured while preventing the generation of gas from the air filter device itself. SOLUTION: The air filter device is equipped with a filter medium 10, an outer frame 20 surrounding the part excepting the filter surface of the filter medium and a seal means 28 sealing the interval of the filter medium and the outer frame and removes a contaminant contained in gas. At least a part of the filter medium is allowed to adhere to the outer frame directly or indirectly by the seal means 28 and the interval between the filter medium 10 and the outer frame 20 is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air filter device, and more particularly, to an air filter device which prevents an organic substance having a bad influence on a semiconductor from leaking even when it is installed in an air purifying device used in a semiconductor manufacturing apparatus or the like. About.

[0002]

2. Description of the Related Art In recent years, in semiconductor manufacturing processes, as the degree of integration of semiconductor wafers increases, the deterioration of yield due to contamination of wafers by gases contained in the manufacturing atmosphere has been regarded as a problem. Causes of gas generation include residues of process gases used in the semiconductor manufacturing process, sodium and boron introduced from outside air, organic substances such as siloxane emitted from building materials, and ammonia generated by people working in clean rooms. There is gas.

In order to remove these gases, various filters corresponding to the components are required. Generally, an activated carbon fiber filter or the like is used for removing organic gas, and an ion exchange filter or the like is used for removing acid gas and alkaline gas. Are used respectively. Further, since there is a possibility that a small amount of dust or the like may come out from the activated carbon fiber filter, a dust filter such as an ULPA filter is installed at the most downstream side.

[0004] These air filter devices are generally composed of a filter medium and an outer frame surrounding the filter medium and holding the filter medium. Need to be sealed. For this purpose, a resin sealing material mainly using an organic solvent such as hot melt or urethane is poured between the filter medium and the outer frame and solidified.

[0005]

However, in the above-described conventional air filter device, it is known that an organic component volatilizes from a sealing material between the filter material and the outer frame to generate gas. However, even if unnecessary gas in the semiconductor process atmosphere is removed, there is a problem in that gas is generated from the air filter device itself, and this gas component flows out downstream.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to prevent air from being generated from an air filter device itself and to secure airtightness between a filter medium and a frame member holding the filter medium. It is an object to provide a filter device.

[0007]

According to a first aspect of the present invention, there is provided a filter medium, an outer frame surrounding a portion other than the filter surface of the filter medium, and sealing means for sealing between the filter medium and the outer frame. In the air filter device for removing a contaminant in a gas, the sealing means directly or indirectly adheres at least a part of the filter medium to the outer frame to allow a space between the filter medium and the outer frame. An air filter device for sealing. Thereby, the airtightness between the filter medium and the outer frame can be ensured without using a member that generates a harmful gas from itself. In the case of indirect contact, a material such as Teflon which does not generate harmful gas is used.

The invention according to claim 2 is characterized in that the sealing means is configured to press the end of the filter medium against the outer frame by the elasticity of the filter medium itself. It is an air filter device of a statement. Thereby, the airtightness between the filter medium and the outer frame can be ensured without using another elastic member, thus simplifying the structure and reducing the possibility of generating harmful gas components. The filter medium is usually formed in a block shape by pleating a sheet-like member having elasticity, and has a greater elasticity. The filter medium may be formed of a sheet-like member, and the sealing means may be configured to sandwich an end of the sheet-like member with the outer frame.

According to a third aspect of the present invention, the outer frame is provided with an elastic member elastically in contact with a part of the filter medium.
2. The air filter device according to claim 1, wherein a part of the filter medium and the elastic member are configured to be in close contact with each other by elasticity of the filter medium itself and elasticity of the elastic member. 3.

The filter medium is usually a sheet-like member having elasticity, and a seal structure can be formed by effectively utilizing the elasticity. When it is pleated and formed into a block shape, the end portion is pulled out and used. A layered portion such as a folded portion may be formed at the end to increase the elasticity. A pocket may be formed in the outer frame, and the end may be pushed into the outer frame so as to be clamped, or the outer frame may be divided and formed, and the end may be clamped therebetween. A space for incorporating the existing framed filter may be provided in the outer frame, and the sealing means may be formed between the outer frame and the framed filter.

The invention according to claim 4 is a clean box having the air filter device according to any one of claims 1 to 3.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show an air filter device according to a first embodiment of the present invention. The air filter device includes a rectangular filter material block 12 obtained by pleating a filter material 10 and a filter material block 12 having a rectangular shape. A rectangular frame-shaped outer frame 1 surrounding the periphery and holding the filter medium block 12
4 mainly. Between the respective pleats, for example, a separator 16 obtained by corrugating a net such as an aluminum lath is inserted to secure a flow path. Thereby, the filter medium block 12 obtained by pleating the filter medium 10
The filter medium 10 has elasticity in the laminating direction.
Note that the separator 16 is not always necessary. Since this air filter is used for total filtration,
The gas to be cleaned flows toward the filter surface of the filter medium block.

The filter medium 10 is formed of at least one of a membrane having an electret filter, a membrane having activated carbon, and a membrane having ion exchange fibers produced by a radiation graft polymerization reaction. Here, the activated carbon may be activated carbon fiber or granular activated carbon.

Here, the ion-exchange fiber is composed of a polymer fiber into which an ion-exchange group is introduced, and the fiber is a substrate composed of an organic polymer, for example, a polymer such as polyethylene or polypropylene, cotton, wool or the like. First, a large number of active sites are generated by irradiating ionizing radiation such as electron beams or gamma rays to natural polymer fibers or woven fabrics, and a monomer having a sulfone group, a carboxyl group, an amino group, etc. It can be obtained by chemical bonding. The above-mentioned ion exchange group can be selected from the group of cations alone, anions alone or a combination of both anions and cations.

The active sites generated by the above-mentioned ionizing radiation irradiation are extremely reactive and are called radicals. By chemically bonding the above-mentioned monomers having free radicals to the active sites, the properties of the substrate can be improved. Separately, the properties of a monomer can be imparted. This technique is called a graft (grafting) polymerization method because the monomer is added to the substrate.

By the above-mentioned radiation graft polymerization method, for example, as a monomer having a sulfone group, a carboxyl group, an amino group or the like which is an ion exchange group on a polyethylene nonwoven fabric substrate, for example, sodium styrenesulfonate, acrylic acid and arylamine acid When combined, it is possible to obtain a nonwoven fabric-like ion exchanger having a significantly higher ion exchange rate than an ion exchanger called a bead-like ion exchange resin used for desalination or production of pure water, and As a monomer capable of introducing an ion-exchange group, for example, styrene, chloromethylstyrene, glycidyl methacrylate, acrylonitrile, acrolein, or the like as a base material, radiation-induced graft polymerization is performed, and then the ion-exchange group is similarly introduced. An ion exchanger in which the shape of the material is maintained can be obtained.

As the activated carbon fibers, for example, those having a configuration in which cellulose fibers are activated by sintering can be used. However, the present invention is not limited thereto. Good properties, any material may be used, including commercial products, as long as the pores are finer than the granular activated carbon and the specific surface area is large, and, like the granular activated carbon, organic and inorganic Adsorbs and removes sulfur compounds, oils and odor components. What incorporated granular activated carbon into a support can also be used as activated carbon.

The electret filter made of polypropylene is prepared as follows. That is, the polypropylene film is split (split the sheet-like polypropylene film into elongated strips) and processed into a nonwoven fabric to form the above-described electret filter.

The outer frame 14 includes a pair of a vertical frame 18 and a horizontal frame 2.
The horizontal frame 20 is provided with a fitting portion 22 for fitting the peripheral portion of the filter medium block 12, and the vertical frame 18 is provided with a fitting portion (not shown) having the same configuration. ing. A screw hole is provided at each of the upper and lower ends of the vertical frame 18, and a screw fastening hole 24 is provided at a position opposing the screw hole of the horizontal frame 20, extending over substantially the entire length of the horizontal frame 20 in the longitudinal direction. By screwing a screw 26 from the screw hole of the vertical frame 18 to the screw fastening hole 24 of the horizontal frame 20, the vertical frame 18 and the horizontal frame 20 are screwed.
Are connected at right angles to each other.

The filter medium block 12 of the fitting portion 22 of the horizontal frame 20
On the bottom surface facing the end surface of the horizontal frame 20, a plurality of strips (2 in FIG.
Ridges 28 are provided. This pointed rib 2
Reference numeral 8 designates a sealing means between the filter medium block 12 and the tip end of the sealing means is formed so as to bite into the end face of the filter medium block 12. Thus, the pointed rib 2
By making the tip of 8 penetrate into the end face of the filter medium block 12, airtightness between the filter medium block 12 and the horizontal frame 20 can be secured.

In order to assemble the air filter device of this embodiment, first, the vertical frames 18 are temporarily assembled on both ends of the lower horizontal frame 20, and the pleated filter medium block 12 is inserted in the pleated laminating direction. At this time, as the filter medium block 12,
The one whose height is longer than the length of the vertical frame 18 is used.
Then, the upper horizontal frame 20 is brought into contact with the upper end surface of the filter medium block 12 and is pushed down to a predetermined position.
6 to fix the horizontal frame 20. Then, since the filter medium block 12 has elasticity in the pleated stacking direction, the tip of the pointed rib 28 bites into the end face of the filter medium block 12 by this elastic force, and the filter medium block 12 and the pointed rib 28 come into close contact with each other, Airtightness between the horizontal frame 20 and the filter medium block 12 is ensured.

As the filter medium 10, as shown in FIG. 3, a composite membrane filter 34 in which activated carbon fibers 30 and a nonwoven fabric or woven fabric 32 of a polymer fiber into which an ion exchange group is introduced is used as a single membrane is used. can do. As shown in the figure, the activated carbon fiber 30 and the nonwoven fabric or woven fabric 32 of polymer fiber are overlapped with each other and stabbed with an infinite number of needles 36 so that the nonwoven fabric or the woven fabric described above is embedded in the activated carbon fiber 30. It can be manufactured with the cloth 32 inserted.

As shown in FIG. 4, an ion exchange filter 38 formed by weaving polymer fiber bundles into which ion exchange groups are introduced so as to cross vertically and horizontally can also be used as the filter medium 10. Similarly, although not shown, an activated carbon fiber membrane formed by weaving an activated carbon fiber bundle can be used as a filter medium.

As described above, by constituting the sealing means with the filter medium, the outer frame, the gasket, etc., the filter can be easily disassembled at the time of disposal after the use of the filter. Processing becomes easy.

FIG. 5 shows an air filter device according to a second embodiment of the present invention. The air filter device has a gasket 40 in addition to the structure of the first embodiment. The airtightness and the reliability are improved by being sandwiched and pressed between the end face of the filter medium block 12 and the horizontal frame 20 provided with the pointed ribs 28. The filter medium shown in FIG. 5 may be a filter obtained by pleating both a chemical filter (activated carbon or an ion exchange membrane) and an electret filter, or a filter obtained by pleating any of the above. The material of the gasket 40 is, for example, appropriately using Teflon material or the like,
By appropriately selecting the elasticity and the thickness, the influence of stress or the like on the filter medium block 12 can be reduced. This is the same in the following embodiments.

FIG. 6 shows an air filter device according to a third embodiment of the present invention. The air filter device has a tapered surface 42 extending toward the center on the inner surface of the fitting portion 22 of the horizontal frame 20. The end of the filter medium block 12 is pressed into the inside of the fitting section 22, and the end of the filter medium block 12 is deformed along the shape of the tapered surface 42 of the fitting section 22 so that the filter medium block 12 and the filter medium block 12 are This is to ensure close contact with the frame 20.

FIG. 7 shows an air filter device according to a fourth embodiment of the present invention. Here, in addition to the configuration of the third embodiment, a gasket 44 is provided between the fitting portion 22 and the filter medium 10, and this gasket 44 is attached to the tapered surface 42 of the fitting portion 22 of the horizontal frame 20. The airtightness and the reliability are further enhanced by being attached to the formed concave portion.

FIG. 8 shows an air filter device according to a fifth embodiment of the present invention. This is done by mounting a curved leaf spring 46 inside the fitting portion 22 of the horizontal frame 20,
The projecting end of the leaf spring 46 and the end face of the filter medium block 12 are pressed against each other by the elastic force of both the leaf spring 46 and the filter medium block 12, thereby ensuring airtightness.

FIG. 9 shows an air filter device according to a sixth embodiment of the present invention, which extends from one side of the fitting portion 22 of the horizontal frame 20 toward the other side. A horizontal rib 48 is provided, and a horizontal pocket portion 50 is formed between the horizontal rib 48 and the bottom of the fitting portion 22. Then, the end of the filter medium 10 constituting the filter medium block 12 is pushed into the horizontal pocket 50, and the filter medium 10 is pressed against the wall of the horizontal pocket 50 by utilizing the elasticity of the filter medium 10 itself.
It is intended to maintain close contact with the device. In this embodiment, the folded portion 10a is formed at the end of the filter medium 10 to be inserted into the horizontal pocket portion 50 to enhance the adhesion of the horizontal pocket portion 50 to the wall.

FIG. 10 shows an air filter device according to a seventh embodiment of the present invention. The air filter device has substantially the same configuration as that of the sixth embodiment, but includes an end portion of the filter medium 10. The winding portion 10b is formed, and the winding portion 10b is inserted into the lateral pocket portion 50 so that the elasticity of the winding portion 10b ensures the close contact with the horizontal frame 20.

FIG. 11 shows an air filter device according to an eighth embodiment of the present invention. The vertical pocket portion 5 is defined by a vertical rib 52 projecting inward from the bottom of the fitting portion 22.
4 is inserted, and the winding portion 10b at the end of the filter medium 10 is inserted into the vertical pocket portion 54, and the close contact with the horizontal frame 20 is ensured by the return force that spreads outward from the winding portion 10b. It was made.

FIG. 12 shows an air filter device according to a ninth embodiment of the present invention. This air filter device is provided at the end of a filter medium 10 instead of the winding portion 10b according to the eighth embodiment. Is pressed into the vertical pocket portion 54 so as to secure the close contact with the horizontal frame 20 by the elastic force of the bent portion 10c.

FIG. 13 shows an air filter device according to a tenth embodiment of the present invention.
At the front end of the filter medium 1, a rectangular engaging concave portion 56 having a rectangular cross section is provided, and a rectangular engaging convex portion 58 having a cross section slightly larger than the engaging concave portion 56 is provided at a position of the fitting portion 22 facing the engaging concave portion 56.
The engagement projection 58 is sandwiched between the engagement recesses 5 with the end 10d of the
6 to secure the close contact with the horizontal frame 20.

FIG. 14 shows an air filter device according to an eleventh embodiment of the present invention.
An engagement recess 60 having an arc-shaped cross section is provided at the base of the fitting portion 2.
2 are provided with engagement projections 62 each having an arc-shaped cross section at a position opposed to the engagement recesses 60.
The engaging protrusions 62 are positioned in the engaging recesses 60 while sandwiching d, and the elasticity of the filter medium 10 itself ensures the close contact with the horizontal frame 20.

FIG. 15 shows an air filter device according to a twelfth embodiment of the present invention, which is a composite membrane filter in which the ion exchange filter material and the activated carbon fiber filter material shown in FIG. 3 are woven together. This is a combination of a filter medium block 12 having a filter medium 34 and a dust filter 64 such as an existing ULPA filter. 15 to 20
The dust filter 64 is sealed with urethane resin, and is not mechanically sealed according to the present invention.
As the dust filter 64, a thin filter having a frame 66 already used is used. In this embodiment, the wind flows in from the left and flows out to the right.

The horizontal frame 20 is provided with a filter material block fitting portion 68 for fitting the filter material block 12 as in the previous case, and a dust filter holding portion 69 for holding the dust filter 64 is provided on the downstream side. The partition rib 72 is formed to extend, and has a partition rib 72 for partitioning the dust filter 64 from which the dust filter 64 is fitted. The end of the filter material block 12 is fitted to the filter material block fitting portion 68 via a gasket 74, whereby airtightness is ensured. If the dust filter 64 is fastened to the dust filter fitting portion 70 together with the frame 66. And airtightness is ensured.

FIG. 16 shows an air filter device according to a thirteenth embodiment of the present invention. This air filter device is different from the twelfth embodiment in that the composite membrane filter 34 (filter medium 10 ) Is extended toward the dust filter 64 in the dust filter holding portion 69 to form an extension 10e, and the extension 10e is sandwiched between the horizontal frame 20 and the frame 66 of the dust filter 64 to improve airtightness. It is intended to be secured.

FIG. 17 shows an air filter device according to a fourteenth embodiment of the present invention, which comprises a holding frame 76 for holding two filters each fitted in a horizontal frame.
Is provided. That is, the inside of the holding frame 76 is partitioned by the partition ribs 82, and the composite membrane filter 34 (the filter medium 1) is formed.
0) is divided into a horizontal frame fitting portion 78 for fitting the horizontal frame 20 for holding the airtightly, and a dust filter fitting portion 80 for fitting the dust filter 64 sandwiched by the frame 66. The frames 20, 66 of the filters 34, 64 are fixed by interference fit.

FIG. 18 shows an air filter device according to a fifteenth embodiment of the present invention. In the air filter device according to the fourteenth embodiment, a horizontal frame fitting portion 78 and a dust filter fitting portion are provided. Cutouts 84a and 84b are provided at the rising portion of 80, and gaskets 86a and 86b are attached to the cutouts 84a and 84b to improve airtightness and reliability.

FIG. 19 shows an air filter device according to a sixteenth embodiment of the present invention. In this embodiment, a holding frame 76 having no partition ribs is used.
6, the horizontal frame 20 which holds the composite membrane filter 34 (the filter medium 10) in an airtight manner and the dust filter 64 are fitted together with an interference fit to secure airtightness.

FIG. 20 shows an air filter device according to a seventeenth embodiment of the present invention, which is different from the air filter device of the sixteenth embodiment in that the composite membrane filter 3 of the holding frame 76 is provided.
A recess 88 is provided in the vicinity of the joint between the horizontal frame 20 that holds the air filter 4 (the filter medium 10) in a gas-tight manner and the dust filter 64, and the gasket 90 is attached to the horizontal frame 20 and the frame 66 of the dust filter 64.
The airtightness and reliability are further enhanced by being embedded so as to contact both sides.

FIG. 21 shows an air filter device according to an eighteenth embodiment of the present invention, which divides a horizontal frame 20 into two parts, a front frame 20a and a rear frame 20b.
The airtightness is ensured by assembling the horizontal frame 20 and the vertical frame 18 with the end 10d of the filter medium 10 sandwiched between the joining portions of the filter frame 10 and the rear frame 20b.

FIG. 22 shows an air filter device according to a nineteenth embodiment of the present invention. The air filter device has a thicker rib portion extending in the horizontal direction of a front frame 20a, and has a stepped portion. The ribs extending in the horizontal direction of the frame 20b are located at the steps, so that the outer surface of the horizontal frame 20 is flush. Other configurations are the same as those of the eighteenth embodiment.

FIG. 23 shows an air filter device according to a twentieth embodiment of the present invention. In the air filter device, the same filter medium as the filter medium block 12 is separately provided between the vertical frame 18 and the filter medium block 12. A small pleat (seal member) 92 that has been pleat-folded several times is sandwiched, and the vertical frame 18, the small pleats 92, and the filter medium block 12 are brought into close contact with each other, so that the airtightness between the vertical frame 18 and the filter medium block 12 is ensured. Things.
Here, by locating the end of the small pleats 92 on the upstream side (the upper side of FIG. 2A indicates the upstream side), even if debris is generated from the cut portion of the filter medium, it is located on the downstream side of the filter. Is not going out.

FIG. 24 shows an air filter device according to a twenty-first embodiment of the present invention. This air filter device is the same as the filter material block 12 separately on the outer periphery of the filter material block 12 obtained by pleating the filter material 10. The filter medium is wound several times to form a head winding part (seal member) 94, and the vertical frame 18 and the horizontal frame 20 are formed.
And the headband portion 94 and the filter medium block 12 are brought into close contact with each other to ensure airtightness. According to this embodiment, the airtightness is further secured between the vertical frame 18 and the filter medium block 12 and between the horizontal frame 20 and the filter medium block 12 by the head winding part 94.

FIG. 25 shows an air filter device according to a twenty-second embodiment of the present invention, which is a combination of both the twentieth embodiment and the twenty-first embodiment to form a vertical frame 18. , Small pleats 92, headband part 94 and filter medium block 12, horizontal frame 20, headband part 94 and filter medium block 1
2 are in close contact with each other to ensure airtightness.

FIG. 26 shows an air filter device according to a twenty-third embodiment of the present invention. In this embodiment, a filter medium block 12 and small pleats 92 are made of a nonwoven fabric 94 such as polyethylene.
a to wrap it in the vertical frame 18 and the horizontal frame 20. Here, the small pleats 92 are made of the same filter medium as the filter medium block 12, but may be a resin material having a predetermined thickness and elasticity without gas generation.

FIG. 27 shows an air filter device according to a twenty-fourth embodiment of the present invention. In this embodiment, a filter medium holding member 96 having a groove 96a along the pleat shape of the filter medium block 12 is used. The end of the filter medium is inserted into 96a and fixed. Then, the holding member 96 is connected to the vertical frame 1.
8 to seal the gap between the outer frame and the filter medium block 12.

FIGS. 28 to 29 show an air filter device according to a twenty-fifth embodiment of the present invention. In this embodiment, comb-shaped cutouts 98a and 100a along the pleated shape of the filter medium block 12 are formed. Filter medium holding member 98 having
100, the filter medium 10 is sandwiched between the filter medium holding members 98,
100 is fastened by a fastener such as a screw to form one constituent member, which is attached to the vertical frame 18 to seal the gap between the outer frame and the filter medium block 12.

FIGS. 30 to 31 show an air filter device according to a twenty-sixth embodiment of the present invention. In the embodiment shown in FIGS. 28 to 29, two filter medium holding members are provided with filter media 18a and 18b. 10 is sandwiched and fastened, and this is used as it is as an outer frame (vertical frame).

In the above-described embodiment, the filter medium block is formed into a block shape by pleating a sheet member having elasticity so as to have elasticity in the laminating direction. However, the filter medium block has elasticity. If you use something,
It is not necessary to use a pleated version.

The results of experiments on the sealing properties of the air filter according to the present invention will be described below. (1) Regarding the combination filters of FIGS. 15 to 20 The upstream filter, that is, the composite membrane filter using the seal according to the present invention is used as the first filter, and the downstream filter, that is, the HEPA using the conventional urethane resin seal is used.
Assuming that the filter is a second filter, one having the following dimensions is used. Filter medium size of the first filter 136 × 136 × 46
(Mm) Filter medium size of the second filter 136 × 136 × 26
(Mm) (Dimensions of frame 66 140 × 140 × 30
(Mm)) Dimensions of combined filter 145 × 145 × 85
(Mm) In the test method, the wind speed was 0.5 m / s and the air volume was 0.6 m ³ / min in the JIS B 9908 particle collection rate test. As a comparison object, HE by a conventional urethane resin seal was used.
Using a PA filter, filter media dimensions are 141 x 141 x 81
(Mm), filter size is 145 x 145 x 85 (m
m). The experimental results show that the average particle collection rate of the 0.3 μm particle size is the combination filter of FIGS.
The HEPA filter using a conventional urethane resin seal is equivalent to 99.97%, indicating that there is no problem in the sealability of the combination filter as compared with the conventional seal.

(2) Regarding the Filters of FIGS. 23 to 26 As the filter medium, ion exchange alone, activated carbon alone or a co-woven fabric thereof is used, and those having the following dimensions are used. Filter size 285 × 285 × 145 (mm) Filter size 305 × 305 × 150 (mm) The test method was as follows: JIS B9901 ammonia removal test Wind speed 0.5 m / s, air volume 2.4 m ³ / min. The object to be compared is a conventional filter with a urethane resin seal, and the filter medium is the same type as the filter of FIGS. 23 to 26 according to the present invention, and has the same dimensions. The experimental results are shown in FIG.
Both the filters of FIGS. 3 to 26 and the conventional filter using a urethane resin seal showed a removal rate of 99%, indicating that the seal according to the present invention had no problem with respect to the sealability as compared with the conventional seal. After the filter was actually used, an ammonia removal test was performed under the same conditions. Each of the filters shown in FIGS. 23 to 26 and a conventional filter with a urethane resin seal is used for one month after being attached to a fan filter unit (a device for supplying clean air from outside to this space) attached to the ceiling of a certain space. did. After the actual use, an ammonia removal test was performed under the same conditions as those described above, and the removal rate of both the filters of FIGS. 23 to 26 and the conventional filter using a urethane resin seal was 99%.
It was found that the seal according to the present invention had no problem in the sealing performance as compared with the conventional seal.

FIGS. 32 to 34 show an example of an apparatus in which the above-described filter device is suitably used. A plurality of semiconductor wafers (substrates to be processed) W are housed in a carrier 110, and are transported and stored. 5 shows a clean box for performing such operations. This clean box is composed of a rectangular cylindrical container body 112, a lid 114 that opens and closes an opening on the upper end side of the container body, and a bottom plate 116 that covers an opening on the lower end side. An airtight holding container 118 is tightly connected.

The holding container 118, that is, the container body 11
2. The material of the lid 114 and the bottom plate 116 is, for example, polycarbonate, polyacetal, polytetrafluoroethylene, polybutylene terephthalate or vinylidene fluoride resin, and further, a mixture of these with an antistatic agent is used. Can be

The inside of the container body 112 has a pair of left and right partition plates 12 having a gap between the lid 114 and the bottom plate 116.
0, the central central chamber 122a and the central chamber 122a
Are partitioned into a pair of side chambers 122b located on both sides of the side wall. A carrier support 124 having a tapered portion extending upward so as to engage with a tapered portion at a lower portion of the carrier 110 is integrally provided on an upper portion of each partition plate 120.

The carrier support 124 in the central chamber 122a
On the lower side, a particle removal filter 126 mainly for removing particles and a chemical filter 128 for removing impurity gas are provided so that air can flow vertically.
It is arranged detachably. On the other hand, in each of the side chambers 122b, a DC brushless motor fan 130 is disposed so as to send out air downward.
Immediately above 0, a backflow preventing chemical filter 132 is provided. At least one of the particle removal filter 126, the chemical filter 128, and the backflow prevention chemical filter 132 is configured as the filter device of the present invention.

The ceiling 114a of the lid 114 is formed in a shape smoothly curved inward, and a triangular upper rectifying plate 134 is provided at the center thereof. Similarly, the inner surface 116a of the bottom plate portion 116 is also formed in an inwardly curved shape, and a triangular lower rectifying plate 136 is provided at the center thereof. Note that a carrier inlet rectifying plate 138 is also provided below the carrier support 124.

General 25 wafer carrier 11 for storing
When 0 is taken as an example, the gap between the first and 25th wafers W and the carrier main body is wider than the gap between the other wafers W, which hinders the uniform flow rate supply to the wafers W. . By providing the carrier inlet rectifying plate 138, the flow rate between the first and 25th wafers W and the gap between the carrier main body at the air inlet portion can be made uniform, and cleaning can be performed efficiently. .

A power supply unit 140 is provided on the side of the container body.
A mounting slot 140a for detachably holding the power supply unit 140 is formed, and a terminal for connecting a power supply terminal of the power supply unit 140 to a terminal of the motor fan 130 is provided in the mounting slot 140a. A control device is built in the power supply unit 140. When the power supply unit 140 is attached to the slot 140a, the DC brushless motor fan 130 operates and stops at the timing of operation / stop according to a control program previously input to the control device. And the number of revolutions is controlled.

The components in this clean box are the same as those in FIG. 34 except for a partition plate that is integrally adhered to the container body.
As shown in (1), all parts are assembled by sequentially stacking each part without using fixing tools such as screws. That is, the filters 126 and 128 arranged in the central chamber 122a are sequentially placed on the upper frame 116b of the bottom plate 116 and held in the central chamber 122a. In the side chamber 122b, a support 144 on which the DC brushless motor fan 130 can be mounted is mounted on the upper frame 116b, and a chemical filter 132 for preventing backflow is mounted and stored on the support 144. ,by this,
The configuration is such that the fastening portion serving as a dust generation source is eliminated and the holding container 118 for cleaning or the like can be easily disassembled.

In this embodiment, the chemical filter 128 is formed by simultaneously woven ion exchange fibers and activated carbon fibers.

In this embodiment, an example is shown in which the chemical filter 128 is constructed by simultaneously weaving the ion exchange fiber and the activated carbon fiber. However, the chemical filter 128 is used alone or in combination with the ion exchange fiber and the activated carbon fiber. A filter may be configured.

Next, as for the particle removal filter 126, the seal according to the present invention is not applied, and an HEPA filter using a normal sealant (urethane or the like), ULPA, etc.
Use a filter. The HEPA filter is an air filter having a particle collection efficiency of 99.97% or more for particles having a rated air volume of 0.3 μm. However, 1980
In the era, especially with the improvement in the integration of semiconductor-related VLSIs, a clean room with a cleanliness of class 10 (10 / ft ³ ) or less is required, and a filter having a higher collection efficiency than a HEPA filter is required. It has come to be required. Correspondingly, a ULP having a balance collection efficiency of 99.9995% or more for particles having a particle size of 0.1 μm.
A filter was commercialized.

At first, glass fibers were used as the filter medium of the ULPA filter, but the glass fibers may react with hydrogen fluoride (HF) vapor used in the semiconductor device manufacturing process to form BF _3. It turned out and became a problem.
In recent years, there are no impurities such as boron or metal, and acids, alkalis,
ULPA filters using PTFE (polytetrafluoroethylene) that is not affected by organic solvents and the like as a filter medium have been commercialized. Here, if necessary, glass fiber and PT
What is necessary is just to use FE properly.

The operation of the thus configured clean box will be described. The space inside the holding container 118 is kept clean in advance, and the filters 126, 128, and 132, the power supply unit 140, and the like are stored in predetermined locations. In a highly clean space such as a clean room, the lid is removed, and the carrier 110 containing the wafer W is supported by the carrier support 1.
24, and cover it tightly with the lid 114. Since the carrier support 124 is located above the two filters 126 and 128, the carrier 110 can be easily stored.

When the external switch is turned on, the motor fan 130 is operated according to a preset program. As a result, the side chamber 122b is lowered and the central chamber 122
a rises and branches into two at the top, and each side chamber 122
A circulation path of the air descending to b and returning to the fan 130 is formed. That is, the DC brushless motor fan 130
After flowing downward in the above, after flowing along the floor surface 116a of the bottom plate portion 116, the air is turned upward by the lower current plate 136, merges, and flows into the ascending flow path.

Here, the air passes through the chemical filter 128 and the particle removal filter 126 and is cleaned, and is guided to the gap between the wafers W by the carrier inlet rectifying plate 138 provided below the carrier support 124. By providing the carrier entrance rectifying plate 138, excessive flow into the gap between the wafer W and the carrier main body is prevented.
The air that has passed between the wafers W flows along the upper straightening plate 134 and the inner surface 114a of the lid 114, inverts, moves down the side chamber 122b, passes through the filter 132, is cleaned, and returns to the motor fan 130. .

In this process, a solid substance such as particles adhered to each part or a gaseous substance generated from the solid substance is transported to a circulating airflow, and the two filters 126,
After being cleaned at 128, it flows to the wafer W. Therefore,
So-called self-contamination from objects inside the container as well as external contamination is prevented. Further, since the wafer W is held in the ascending flow channel and is located on the upstream side of the lid 114 which is easily contaminated by the outside air at the time of opening and closing, contamination from the future is prevented.

As an operation pattern of the motor fan 130, an appropriate mode can be considered according to the use condition of the clean box. Generally, in the initial stage, the operation is performed continuously or at a high flow rate, and the operation for positively removing the contamination brought into the container from the outside is performed. After a certain amount of time has elapsed, the flow rate is reduced or the operation is performed intermittently to perform an operation for preventing contamination generated from the accommodated wafers W and components in the container. Thus, the life of the power supply can be extended.

Here, in the intermittent operation, the motor fan 1
If contaminants are generated from the motor when the motor 30 stops, the backflow prevention filter 132 is provided, so that the backflow is prevented from flowing back to the wafer W and directly contaminating the wafer W.

According to the present clean box, a circulating flow is formed in the holding container, which is physically and chemically cleaned with a particle removal filter and a chemical filter, and then flows toward the substrate holding portion. It is possible to provide a clean box that not only efficiently prevents contamination of the substrate from the external atmosphere, but also effectively prevents contamination generated from the substrate itself. In addition, the present invention can contribute to improvement in the production yield and quality of semiconductor wafers, photomasks, and the like for which contamination by gaseous impurities must be extremely avoided. Since the particle removal filter and the chemical filter are arranged on the upstream side of the substrate holding portion of the ascending flow channel, the substrate can be easily taken in and out from above, and the lid of the container is located downstream of the substrate holding portion. Therefore, the substrate is prevented from being contaminated from a container that is easily contaminated during opening and closing.

[0073]

As described above, according to the present invention, airtightness between the filter medium and the outer frame can be ensured without using a member that generates harmful gas from the air filter device itself. In particular, by being configured to be pressed against the outer frame by the elasticity of the filter medium itself, without using another elastic member, it is possible to ensure airtightness between the filter medium and the outer frame, and to use another elastic member. Without using, therefore,
The above effects can be obtained with a simple configuration. Therefore, it can be used in a space requiring a clean atmosphere such as in semiconductor manufacturing to improve quality and production efficiency.

[Brief description of the drawings]

FIG. 1 shows an air filter device according to a first embodiment of the present invention, in which (a) is a plan view, (b) is a front view, and (c) is a right side view.

FIG. 2 is an enlarged sectional view taken along line AA of FIG.

FIG. 3 is a diagram attached to an example of a filter medium and a description of a forming method thereof.

FIG. 4 is a plan view of another example of the filter medium.

FIG. 5 is an enlarged sectional view of a main part showing an air filter device according to a second embodiment of the present invention.

FIG. 6 is an enlarged sectional view showing a main part of an air filter device according to a third embodiment of the present invention.

FIG. 7 is an enlarged sectional view of a main part showing an air filter device according to a fourth embodiment of the present invention.

FIG. 8 is an enlarged sectional view of a main part showing an air filter device according to a fifth embodiment of the present invention.

FIG. 9 is an enlarged sectional view showing a main part of an air filter device according to a sixth embodiment of the present invention.

FIG. 10 is an enlarged sectional view showing a main part of an air filter device according to a seventh embodiment of the present invention.

FIG. 11 is an enlarged sectional view showing a main part of an air filter device according to an eighth embodiment of the present invention.

FIG. 12 is an enlarged sectional view showing a main part of an air filter device according to a ninth embodiment of the present invention.

FIG. 13 is an enlarged sectional view showing a main part of an air filter device according to a tenth embodiment of the present invention.

FIG. 14 is an enlarged sectional view showing a main part of an air filter device according to an eleventh embodiment of the present invention.

FIG. 15 is a main part enlarged sectional view showing an air filter device according to a twelfth embodiment of the present invention.

FIG. 16 is an enlarged sectional view showing a main part of an air filter device according to a thirteenth embodiment of the present invention.

FIG. 17 is an enlarged sectional view showing a main part of an air filter device according to a fourteenth embodiment of the present invention.

FIG. 18 is an enlarged sectional view showing a main part of an air filter device according to a fifteenth embodiment of the present invention.

FIG. 19 is an essential part enlarged sectional view showing an air filter device according to a sixteenth embodiment of the present invention.

FIG. 20 is an enlarged sectional view showing a main part of an air filter device according to a seventeenth embodiment of the present invention.

FIGS. 21A and 21B show an air filter device according to an eighteenth embodiment of the present invention, where FIG. 21A is a perspective view and FIG.

FIGS. 22A and 22B show an air filter device according to a nineteenth embodiment of the present invention, wherein FIG. 22A is a perspective view and FIG.

23A and 23B show an air filter device according to a twentieth embodiment of the present invention, wherein FIG. 23A is an exploded perspective view, and FIG. 23B is an enlarged sectional view of a main part.

24A and 24B show an air filter device according to a twenty-first embodiment of the present invention, wherein FIG. 24A is an exploded perspective view, and FIG.

FIGS. 25A and 25B show an air filter device according to a twenty-second embodiment of the present invention, wherein FIG. 25A is a perspective view and FIG.

26A and 26B show an air filter device according to a twenty-third embodiment of the present invention, wherein FIG. 26A is an exploded perspective view of the whole, and FIG. 26B is a perspective view of a main part.

FIG. 27 is an exploded perspective view showing an air filter device according to a twenty-fourth embodiment of the present invention.

FIG. 28 is an exploded perspective view showing an air filter device according to a twenty-fifth embodiment of the present invention.

FIG. 29 is an exploded perspective view showing an assembling step of a twenty-fifth embodiment of the present invention.

FIG. 30 is an exploded perspective view showing an air filter device according to a twenty-sixth embodiment of the present invention.

FIG. 31 is an exploded perspective view showing an assembling step of a twenty-sixth embodiment of the present invention.

FIG. 32 is a front sectional view showing a clean box using the air filter device of the present invention.

FIG. 33 is a sectional view taken along line AA of FIG. 32;

FIG. 34 is an exploded perspective view illustrating an article constituting the clean box of the embodiment of FIG. 32;

[Explanation of symbols]

Reference Signs List 10 filter medium 12 filter medium block 14 outer frame 18 vertical frame (outer frame) 20 horizontal frame (outer frame) 20a front frame 20b rear frame 22 fitting portion 28 pointed rib 34 composite membrane filter (filter medium) 38 ion exchange filter (filter medium) 40,44,74,84a, 84b, 90 Gasket 42 Tapered surface 46 Leaf spring 50,54 Pocket 56,60 Engagement concave 58,62 Engagement convex 64 Dust removal filter 72,82 Partition rib 76 Holding frame 92 Small pleat (Seal member) 94 Headband (Seal member)

Continuation of the front page (72) Inventor Yoko Yokobu 11-1 Asahimachi, Haneda, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 4D058 JA14 JB14 JB23 JB24 JB25 JB39 KC33 KC35 KC63 KC66 SA04 TA03 TA04 TA07

Claims (4)

[Claims] An air filter for removing a pollutant in a gas, comprising: a filter medium; an outer frame surrounding a portion other than the filter surface of the filter medium; and sealing means for sealing between the filter medium and the outer frame. In the apparatus, the sealing means seals a gap between the filter medium and the outer frame by directly or indirectly adhering at least a part of the filter medium to the outer frame. . 2. The air filter device according to claim 1, wherein the sealing means is configured to press an end portion of the filter medium against the outer frame by the elasticity of the filter medium itself. 3. An outer frame is provided with an elastic member elastically in contact with a part of the filter medium, and a part of the filter medium and the elastic member are formed by elasticity of the filter medium itself and elasticity of the elastic member. The air filter device according to claim 1, wherein the air filter device is configured to be in close contact with the air filter device. 4. A clean box having the air filter device according to claim 1.