JP2000189736A - Air filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the air tightness between a filter medium and a frame material while preventing the generation of a gas from an air filter device itself by interposing a sealing material made of an epoxide resin free from the generation of gas between the filter medium and the outside frame surrounding the peripheral part of the filter medium. SOLUTION: The air filter device installed in an air purifier uses in a semiconductor manufacturing device or the like is constituted of a pleated rectangular filter medium block 12 and the rectangular outside frame holding the filter medium block 12 and a separator is inserted between respective pleats. In such a case, the sealing materials 30a-30d made of the resin free from the generation of the gas are stuck to each upper and lower and left and right end face of the filter medium block 12. As the resin free from the generation of the gas, epoxide resin, urethane resin and the like are mentioned and for example, in modified epoxide resins, an epoxide resin obtained by mixing a bisphenol A type epoxide resin with a modified alicyclic polyamine in a prescribed mixing ratio is used.

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 sealing material made of a resin mainly using an organic solvent such as hot melt or urethane is poured between the filter medium and the outer frame to be solidified, or both are adhered using a double-sided tape.

[0005]

However, in the above-described conventional air filter device, it is known that the organic components are volatilized from the sealing material between the filter material and the outer frame and the double-sided tape to generate gas. Therefore, even if unnecessary gas in the semiconductor process atmosphere is removed, there is a problem 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 problems, and it is possible to prevent the generation of gas from an air filter device itself and to secure the airtightness between a filter medium and a frame material holding the filter medium. An object of the present invention is to provide an air filter device.

[0007]

The invention according to claim 1 has a filter medium and an outer frame surrounding a peripheral portion of the filter medium,
An air filter device for removing contaminants in a gas, wherein a seal member made of an epoxy resin that does not generate a gas is provided between the filter material and an outer frame. Thereby, airtightness between the filter medium and the outer frame can be ensured without generating harmful gas from the air filter device itself. It is preferable that the resin constituting the sealing material is molded so as to be integrally attached to the end face of the filter material. Further, it is preferable that the sealing material is provided integrally with a peripheral portion of the filtering material.

According to a second aspect of the present invention, there is provided an air filter device for removing a pollutant in a gas, comprising a filter medium, and an outer frame made of resin and in close contact with the filter medium so as to surround the periphery of the filter medium. Wherein the resin is an epoxy resin that does not generate gas. Accordingly, it is possible to prevent the gas from being generated from the air filter device itself and to secure the airtightness between the outer frame and the filter medium.

According to a third aspect of the present invention, there is provided a holding container, a partition wall for forming a circulation flow path in the holding container, and a substrate holding portion for holding a substrate substantially parallel to a part of the circulation flow path. 3. A motor fan which is built in the holding container and forms a circulating airflow circulating in the circulation flow path, and the air filter device according to claim 1 or 2 which is disposed in the circulation flow path. It is a clean box. Accordingly, the substrate can be held while maintaining the cleanliness of the substrate without using the air filter device itself as a contamination source.

According to a fourth aspect of the present invention, a cartridge having a filter medium unit formed in a cylindrical shape by rolling a filter medium and bonding an end thereof to a part of the filter medium is detachably provided inside, In the line filter installed in the middle of the pipe, the bonding means is an epoxy resin which does not generate gas.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show an air filter device according to an 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 surrounding the filter material block 12. It mainly comprises a rectangular frame-shaped outer frame 14 for holding the filter medium block 12. Between each pleat, for example, a separator 16 formed by corrugating a metal net made of resin or aluminum lath is inserted to secure a flow path.
Thus, the filter medium block 12 obtained by pleating the filter medium 10 has elasticity in the laminating direction of the filter medium 10. Note that the separator 16 is not always necessary. Since this air filter device is used for the total filtration of gas,
The gas to be cleaned flows in.

The filter medium 10 is a HEPA filter, ULPA
A membrane having at least one of a filter or an electret filter, a membrane having activated carbon fibers, and at least one of a membrane having a nonwoven fabric or woven fabric of ion exchange fibers produced by a radiation graft polymerization reaction. I have.

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 made of an organic polymer, for example, a polymer such as polyethylene or polypropylene, cotton, wool, or the like. First, ionizing radiation such as electron beam or gamma ray is applied to natural polymer fibers or woven fabrics to generate many active sites, and a monomer having a sulfone group, carboxyl group, 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 irradiation with ionizing radiation are extremely highly reactive and are called radicals. 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 structure obtained by sintering and activating cellulose fibers can be used. However, the present invention is not limited to this. 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.

A HEPA filter, a ULPA filter and a polypropylene electret filter made of glass fiber or polyfluorinated ethylene fiber are prepared as follows. That is, glass fibers or polyfluorinated ethylene fibers are collected and processed into a non-woven fabric to form a HEPA filter and an ULPA filter, and the polypropylene film is split (a sheet-like polypropylene film is slit) to form a non-woven fabric. Processing is performed to form the above-described electret filter.

The filter medium 10 may be a pleated weave of activated carbon fibers and an ion-exchange filter. As shown in FIG. 2, the activated carbon fibers 20 and the polymer fibers into which the ion-exchange groups are introduced are used. Non-woven or woven fabric 2
2 and a composite membrane filter 24 having a single membrane shape can be used. As shown in the figure, the activated carbon fiber 20 and the nonwoven fabric or the woven fabric 22 of the polymer fiber are overlapped with each other and stabbed with an infinite number of needles 26, so that the above-mentioned nonwoven fabric or the woven fabric is placed in the activated carbon fiber 20. It can be manufactured by inserting the cloth 22 therein.

As shown in FIG. 3, an ion exchange filter 28 formed by weaving polymer fiber bundles into which ion exchange groups are introduced so as to intersect 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 shown in FIG. 4, sealing members 30a, 30b, 30c, and 30d made of a resin that does not generate gas are fixed to the upper, lower, left, and right end surfaces of the filter medium block 12, respectively. Since high dimensional accuracy is required for the seal members 30a to 30d, the seal members 30a to 30d are formed using a mold, for example.
Epoxy resins and urethane resins can be considered as resins that do not generate gas. For example, among modified epoxy resins, for example, a bisphenol A-type epoxy resin as a base material containing an additive for preventing yellowing and resistance to ultraviolet light, and as a curing agent, for example, modified aliphatic polyamines, Epoxy resin obtained by mixing a base material, an aliatic amine (aliphatic amine) with an additive, at a predetermined mixing ratio (example of reaction formula)

Embedded image Among modified epoxy resins, an epoxy resin obtained by mixing a bisphenol A type epoxy resin and a modified alicyclic polyamine (epoxy adduct of isophorone diamine) as a curing agent at a predetermined mixing ratio (example of reaction formula)

Embedded image (Modification means changing the properties of the synthetic resin by replacing some of the basic components of the synthetic resin with other components). For the above-mentioned modified epoxy resin, use a dechlorinated resin (to eliminate the volatilization of chlorine-based components) and use a resin with a high boiling point (to prevent volatilization at a high boiling point and to prevent gas generation). .

The above modified aliphatic polyamine and modified alicyclic polyamine were prepolymerized to remove those having a small molecular weight, and to increase the viscosity of only those having a large molecular weight. In addition, the above mixing ratio is set at the theoretical mixing ratio so that both react at 100% in the above mixing. Further, this reaction is an addition polymerization reaction and has no by-product unlike the condensation reaction. The epoxy resin described above is thermosetting and does not generate volatile substances (gas generation) during curing. For the reasons described above, the epoxy resin does not emit gas.

In addition to the above-mentioned epoxy resins, resins that do not generate gas include modified polyols (comprising a propylene glycol polymer with a curing accelerator) and modified M.P.
D. A hard urethane resin in which I (methylene biphenyl diisocyanate, diphenylmethane diisocyanate modified with carbodiimide) is mixed at a predetermined mixing ratio is considered. (Example of reaction formula)

Embedded image

In addition to the above epoxy resin,
As a component of the resin that does not generate gas,
A mixture of the same modified epoxy resin as in the case of the above epoxy resin and an amino alcohol or a dialcohol can be considered. Amino alcohol and dialcohol are obtained by replacing amino groups of polyamine with alcohol groups. (Chemical formula)

Embedded image

The outer frame 14 is composed of a pair of vertical frames 32 and horizontal frames 34 made of metal such as aluminum, respectively. The vertical frame 32 and the horizontal frames 34 are fitted with the peripheral portions of the filter medium block 12. A wearing portion is provided. A screw hole is provided at each of the upper and lower ends of the vertical frame 32, and screw fastening holes extending substantially over the entire length in the longitudinal direction of the horizontal frame 34 are provided at positions facing the screw holes of the horizontal frame 34, respectively. By screwing the screw 36 from the screw hole of the vertical frame 32 to the screw fastening hole of the horizontal frame 34,
The vertical frame 32 and the horizontal frame 34 are connected at right angles to each other.

The steps of manufacturing the air filter device of this embodiment will be described. First, resin sealing materials 30a to 30d that do not generate gas are attached to the end face of the filter material block 12 formed by pleating. This is performed in a process as shown in FIG.

First, a lower mold 44 having a bottom portion 40 formed in a shape that does not cause leakage or accumulation of resin and side portions 42 tiltably connected to both ends of the bottom portion 40, and an upper end of the lower mold 44. An upper die 46 that can be fastened at a predetermined position via a fastener such as a screw is prepared. When the resin is solidified on the end face of the filter medium block 12, the lower mold 44 and the upper mold 46 have a filter medium block 12 in which the resin is solidified inside the outer frame 14 including the vertical frame 32 and the horizontal frame 34. The inner shape and dimensions are set so that they can be fitted without any problem.

Next, with the upper end of the side portion 42 slightly open, molten resin that does not generate gas is poured into the bottom portion 40, the filter medium block 12 is dropped from above, and the side portion 42 is closed. Thereafter, the upper mold 46 is fixed via a fastener such as a screw at the upper end of the side surface 42 to close the mold. The state where the lower end of the filter medium block 12 is immersed in the resin is maintained for a predetermined time until the resin is cured, and a sealing material made of the resin is attached to one end surface of the filter medium block 12. By providing a film or a bellows between the bottom surface 40 and the side surface 42, the resin may be prevented from leaking from between the bottom surface 40 and the side surface 42. ,
The means for preventing resin leakage as described above is unnecessary.

Next, the molds 44 and 46 are opened, and the same operation is performed on the end surface opposite to the end surface where the resin is solidified to cause the resin to adhere. Next, the same operation is performed on the two end surfaces on which the resin is not yet attached. Go to each. For example, surface C
(30c) → D (30d) → A (30a) → B (30
b) or in the order of plane A (30a) → B (30b) → C
The resin is deposited in the order of (30c) → D (30d). As described above, by first forming the sealing material of the resin on the end surfaces facing each other, the filter material block 12 is easily gripped by the side surface portion 42, and the resin is formed rigidly on the filter material block 12 to handle the filter material. A flight can be planned.

The curing conditions of the above-mentioned epoxy resin as a resin are shown below. Filter material block size (mm) 285 (W) x 285 (H) x 48 (D) Filter material HEPA filter Total amount of resin used 400 cc Curing time 60 ° C, 8 to 10 hours Thickness of formed resin layer 5 mm * Outer frame size 305 (W) × 305 (H) × 50 (D)

The curing conditions for the above-mentioned epoxy resin as a resin are shown below. Filter material block size (mm) 285 (W) x 285 (H) x 48 (D) Filter material HEPA filter Total amount of resin used 400 cc Curing time 25 ° C, 8 hours Thickness of formed resin layer 5 mm * Outer frame size 305 (W ) × 305 (H) × 50 (D)

FIGS. 6 to 8 show a mold provided with another fastening mechanism for the lower mold 44 and the upper mold 46. Hook pieces 50 are provided at both ends of the upper mold 46, and side faces of the lower mold 44 are provided. A lever 54 having a fastener 52 that can be engaged with the hook piece 50 is fixed to the upper end of the lever 42. Further, in this example,
By providing the film or the bellows 56 between the bottom surface portion 40 and the side surface portion 42, the resin is prevented from leaking from between the bottom surface portion 40 and the side surface portion 42. In the case where the curing of the resin is fast, the above-described means for preventing the resin from leaking is unnecessary.

According to this embodiment, as shown in FIG. 8, a lever 54 provided on the side surface portion 42 so as to be swingable is lifted up (FIG. 8).
(A)), a U-shaped fastener 52 slidably provided on the lever 54 is hooked on the hook piece 50 of the upper die 46 (FIG. 8).
(B)). Then, the lever 54 is lowered, and the fastener 52 is fitted into the receiving portion of the hook piece 50 (FIG. 8C). The lever 54 is further lowered, and the upper die 46 is fixed to the upper end of the side surface portion 42. Close the mold.

At this time, the hook piece 50 is bent downward by the fastener 52, and the return force f generates a moment about the fulcrum of the lever 54 via the fastener 52 as shown in FIG. Since the fulcrum exists on the extension of the vector of the force f, or the moment is applied in the direction in which the lever 54 is pressed against the side surface 42, the lever 54 does not move upward, and is surely moved upward. Type 4
6 can be fixed to the side part 42.

As described above, using the molds 44 and 46, the sealing members 30a to 30
By attaching 30d, the accuracy of the shape and dimensions can be increased, and the filter medium block 12 provided with the sealing materials 30a to 30d can be accurately placed in the outer frame 14.

According to the above-described method, the filter medium block 12 having the four end faces to which the sealing materials 30a to 30d made of resin are attached is incorporated into the outer frame 14 composed of the vertical frame 32 and the horizontal frame 34 (see FIG. 1). This is because the vertical frame 32 is temporarily assembled at both ends of the lower horizontal frame 34, the filter medium block 12 is inserted into the vertical frame 32, and the upper horizontal frame 34 is fitted to the upper end surface of the filter medium block 12 at a predetermined position. Then, the screw 36 is tightened to fix the horizontal frame 34. As a result, the sealing materials 30a to 30d attached to the end surfaces of the filter medium block 12 are in close contact with the bottoms of the fitting portions of the vertical frame 32 and the horizontal frame 34, and airtightness is secured here.

When the filter medium 10 is to be replaced, the filter frame 12 whose four surfaces have been solidified with resin can be easily discarded by opening and taking out the outer frame 14, and the outer frame 14 can be reused without being discarded. it can. Here, if a resin material is used for the separator 16 and a flammable material such as a nonwoven fabric material is used for the filter material, the filter material block 12 can be discarded as a flammable material as it is.

In the above description, the sealing resin is provided between the filter medium block 12 and the outer frame 14. However, the outer frame itself holding the filter medium is made of a resin that does not generate gas, and the filter medium block 12 is connected to the filter medium block 12 by the above-described method. The outer frame 14 may be directly attached. Thus, an air filter device that does not generate gas can be configured without using the sealing material itself. The outer frame made of resin can be formed by using the mold shown in FIGS. 5 to 8 so that the inner dimensions are set to be the same as the outer dimensions of the vertical frame 32 and the horizontal frame 34. .

In this case, since the vertical frame 32 and the horizontal frame 34 do not require much dimensional accuracy, the molding die can be greatly simplified. That is, in FIG. 5, the side surface portion 42 and the upper die 46 of the lower die 44 are not necessarily required. For example, the lower die 44 can be formed as long as there is only a box-shaped bottom portion that is open at the top.

When a resin material is used for the separator 16 and a combustible material such as a nonwoven fabric material is used as the filter material, the filter can be disposed of as a combustible material when the filter is replaced. At this time, if the resin forming the vertical frame 32 and the horizontal frame 34 is transparent, the pleated filter medium block 12 is formed from the outside.
Can be seen through and the appearance is poor, so it is half (not) as resin
It is desirable to use a transparent one. In the above embodiment, a layer made of a resin that does not generate gas is provided integrally on the periphery of the filter medium block 12. For example, a layer of a resin that does not generate gas is formed independently (by hardening), and May be provided as a separate member on the periphery of the.

The experimental results of the sealing properties when the above-mentioned epoxy resin is used as the resin are shown below. Test method Particle collection rate test specified in JIS B 9908 Conditions: Air volume 2.1 m ^{3 /} min (LV 0.5 m / s) Particle size 0.3 μm Filter media block size 285 (W) × 285 (H) × 48 (D ) Filter material HEPA filter Seal layer thickness 5mm Outer frame size 305 (W) × 305 (H) × 50 (D) A filter using a conventional urethane seal under the above conditions,
Regarding the three types of filters of the present invention using an epoxy resin as a seal, the particle collection rates were all 99.97%, and it was found that the filter according to the present invention had no problem in terms of sealing performance. In the above experiment, the outer frame was provided for the filter of the present invention using the epoxy resin as a seal. However, even when the outer frame was omitted (the resin layer also served as the outer frame), the particle collection rate was also the same. It was 99.97%.

The experimental results of gas generating properties when the above-mentioned epoxy resin is used as the resin are shown below. Filter material block size 285 (W) × 285 (H) × 48 (D) Filter material HEPA filter Seal layer thickness 5mm Outer frame size 305 (W) × 305 (H) × 50 (D) Content of test: Organic on wafer The kimono was subjected to semi-quantitative analysis in terms of C-16. Use tester: GC-MS Result: Use of epoxy resin 0.0 ng / g · hour Conventional urethane use 0.9 ng / g · hour From the above, it was found that there was no gas generation. As a result of an experiment on the gas generating properties of the epoxy resin under the same conditions as those of the epoxy resin, it was found to be 0.0 ng / g · hour similarly to the epoxy resin of the above, indicating no gas generating properties.

FIGS. 9 to 11 show a clean box using the above-described air filter device. The clean box uses a plurality of semiconductor wafers (substrates to be processed) W in a carrier 1.
It is housed in a state where it is housed in the apparatus 10 and transported and stored. 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, an antistatic agent may be mixed therein. .

The inside of the container main body 112 includes 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. These particle removal filters 126,
The chemical filter 128 and the two backflow preventing chemical filters 132 are each hermetically sealed with the configuration of the air filter device described with reference to FIGS. 1 to 8, that is, with a sealing material made of a resin that does not generate gas.

The ceiling 114a of the lid 114 is formed into 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 25 wafers
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 the clean box are the same as those in FIG. 11 except for a partition plate integrally bonded 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 weaving the non-woven fabric or woven fabric of ion exchange fiber and the activated carbon fiber. May be used alone or in combination to form a chemical filter.

Hereinafter, the particle removal filter 126 will be described. The HEPA filter has a particle size of 0.
The air filter has a particle collection efficiency of 99.97% or more for 3 μm particles. However, in the 1980's, especially as the integration of semiconductor-related VLSIs increased,
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 has been required. Correspondingly, for particles having a particle size of 0.1 μm, 99.
ULPA filters having a particle collection efficiency of 9995% or more have been commercialized.

[0052] Initially, the filter medium of ULPA filter, it had been using glass fibers, the glass fibers which react with hydrogen fluoride (HF) vapor used in the production process of the semiconductor device to generate a BF ₃ It turned out and became a problem. In recent years, ULPA filters using PTFE (polytetrafluoroethylene), which is free from impurities such as boron and metals and is not attacked by acids, alkalis, organic solvents, and the like, as a filter medium have been commercialized. Here, glass fiber and PTFE may be selectively used as needed.

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 above the two filters 126 and 128, storage of the carrier 110 is easy.

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 is cleaned by passing through the chemical filter 128 and the ULPA filter 126, 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, solid substances such as particles attached to each part or gaseous substances generated from these substances are carried to the 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 an operation is performed to positively remove contamination introduced from outside into the container. After a certain amount of time has elapsed, an operation is performed to reduce the flow velocity or perform the operation intermittently to prevent 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 such a clean box, a circulating flow is formed in the holding container, which is physically and chemically cleaned by the particle removal filter and the 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 housed substrate from the outside atmosphere but also effectively prevents contamination generated from the substrate itself. This can contribute to an improvement in the production yield and quality of semiconductor wafers, photomasks, and the like for which contamination due to particulate or 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 in the ascending flow path,
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, so that the substrate is prevented from being contaminated from a container that is easily contaminated during opening and closing. In addition, the used particle removal filter 12
6. Since the chemical filter 128 and the two backflow preventing chemical filters 132 are all hermetically sealed with a sealing material made of a resin that does not generate gas, these filter devices themselves do not become a source of contamination, and It contributes to maintaining the cleanliness of the substrate.

An example in which the epoxy resin which does not generate gas according to the present invention is applied to a cartridge filter of a line filter will be described below. FIG. 12 shows a line filter L installed between the pipes P ₁ and P ₂ . Inside the line filter L, a cartridge filter 6 provided with a filter medium 10a is provided.
0 is attached. The cartridge filter 60 is provided with an EP1 × membrane (ion exchange membrane) in an inner cylinder 61 having a perforated side surface.
The filter member 10a is wound around, and its end is bonded to the filter surface of the filter member 10a with an epoxy resin that does not generate gas to form a cylindrical filter member unit. An outer cylinder 64 is provided outside the cartridge filter 60 to form a line filter L.

[0062] As shown in FIG. 13, the gas in the piping _{P 1} enters the line filter L, cartridge filter 60
By it is cleaned, leaving the line filter L to the pipe P _2. The filter material of the cartridge filter may be wound into a cylindrical shape by bonding the ends of the filter material with the epoxy resin. As shown in FIG. 14, the filter medium 10b may be pleated. In FIG. 14, the ends of the filter medium 10b are bonded together.

[0063]

As described above, according to the present invention,
It is possible to provide an air filter device that can secure airtightness between a filter medium and an outer frame using a sealing material without generating a gas such as an organic substance component. Further, since a resin that does not generate gas is used as an adhesive for the filter medium, gas generation from the line filter can be prevented. 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 an embodiment of the present invention, wherein (a) is a plan view, (b) is a front view, and (c) is a right side view.

FIG. 2 is a diagram attached to an example of a filter medium used in the air filter device shown in FIG. 1 and a method of forming the same.

FIG. 3 is a plan view showing another example of the filter medium.

FIG. 4 is a perspective view of a filter medium block having a sealing material made of resin adhered to an end face.

FIG. 5 is an exploded perspective view showing a filter material block and a mold for attaching a sealing material made of resin to the end face thereof.

FIG. 6 is a perspective view showing a filter medium block and another mold for attaching a sealing material made of resin to an end face thereof.

FIG. 7 is an enlarged front view showing a part of FIG. 6 in an enlarged manner.

FIG. 8 is a perspective view showing a fastening operation (mold closing operation) of the mold shown in FIG. 6 in the order of steps.

FIG. 9 is a front sectional view showing a clean box using the air filter device of the present invention.

FIG. 10 is a sectional view taken along line AA of FIG. 9;

FIG. 11 is an exploded perspective view illustrating an article constituting the clean box according to the embodiment of FIG. 9;

FIG. 12 is a view showing an embodiment in which the epoxy resin that does not generate gas according to the present invention is applied to a cartridge filter of a line filter.

FIG. 13 is a longitudinal sectional view of the embodiment of FIG.

FIG. 14 is a transverse sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Filter medium 12 Filter medium block 14 Outer frame 30a-30d Sealing material 32 Lower die 34 Upper die 40 Bottom part 42 Side part 44 Lower die 46 Upper die

Continuation of the front page (72) Inventor Yoko Yoko, 11-1 Asahimachi, Haneda, Ota-ku, Tokyo F-term in the Ebara Corporation (reference) 3L058 BF03 BF09 BG01 BG03 BG04 4D019 AA01 BA03 BA13 BB02 BB03 BB08 BC04 CA01 CA02 CA03 CB01 CB03 CB04 4D058 JA10 JA14 KA01 KA12 KA15 KA23 KC04 KC64 QA01 QA21

Claims (4)

[Claims] 1. An air filter device having a filter medium and an outer frame surrounding a peripheral portion of the filter medium and removing contaminants in a gas, wherein an epoxy which does not generate gas is provided between the filter medium and the outer frame. An air filter device provided with a sealing material made of resin. 2. An air filter device comprising a filter medium and an outer frame made of resin and closely contacting the filter medium so as to surround a periphery of the filter medium, wherein the resin removes gas from the resin. An air filter device, which is an epoxy resin that is not generated. 3. A holding container, a partition wall that forms a circulation flow path in the holding container, a substrate holding portion that holds a substrate substantially in parallel with a part of the circulation flow passage, and a built-in storage container. A clean box, comprising: a motor fan that forms a circulating airflow that circulates through the circulation flow path; and the air filter device according to claim 1 or 2 that is disposed in the circulation flow path. 4. A cartridge having a filter medium unit formed in a cylindrical shape by rolling the filter medium and bonding its end to a part of the filter medium is detachably provided inside, and is installed in the middle of the pipe. In the line filter, the bonding means is an epoxy resin that does not generate gas.