JP2001062237A - Chemical filter, its use method, clean room, semiconductor production apparatus and fan filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily discriminate and predict the life of a filter by constituting a parallel flow type filter in which the air passing the filter flows approximately parallel along the surfaces of the filter media constituting the filter of the plural filter media varying in the length of the direction where the air flows. SOLUTION: The chemical filter which is used for a clean room, semiconductor production apparatus, etc., and removes the gaseous contaminants in the air is formed by providing the filter with two kinds of varying length portions of long filter medium portions 4 and short filter medium portion portions 5 at the length of the filter media in the air flow direction. The method of predicting the life of the parallel flow type filter includes a method of periodically measuring the concentration of the contaminants downstream of the long filter medium portions 4 and downstream of the short filter medium portions 5 and making discrimination that the filter is nearly the end of its life where a difference arises at their concentration level. Also, the downstream side in the filter of the short filter medium portions 5 is provided with a space 3 and a filter medium holding frame is disposed in this space 3 so as to come into contact with the downstream portions of the filter media within the outside frame of the filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a chemical filter, which is excellent in discriminating and predicting a filter life, and is used, for example, in a clean room, a semiconductor manufacturing apparatus and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for judging the service life of a chemical filter, a pair of air pollutant trapping devices is arranged on the upstream and downstream sides of the filter in Japanese Patent Application Laid-Open No. 9-250973, and adsorbed on the air pollutant trapping device. There has been a method for determining that the filter has reached the end of its service life when the difference between the determined substance amounts is small.

A chemical filter for determining the life is disclosed in Japanese Patent Laid-Open Publication No. Hei 8-266683, which comprises a frame and a filter medium which is removably mounted in the frame via a mounting / removing means. There is known a chemical filter that is detached as a filter.

However, the technique disclosed in Japanese Patent Application Laid-Open No. 9-250973 requires the installation of an air pollutant capturing device separately from the filter main body, and is difficult to install in a limited space such as in a semiconductor manufacturing apparatus. was there. Furthermore, this method can measure that the service life has finally come, but it is insufficient from the viewpoint that it is difficult to predict the service life during and after use.

On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. Hei 8-266683, it is necessary to extract a part for predicting the life, which is formed separately from the main filter medium part, for estimating the life. It is necessary to perform operations such as stopping or taking out the entire filter and taking it out again, which is extremely troublesome. Further, in this technique, it is difficult to keep the air flow in both parts the same because the extraction part and the main body part need to be configured separately, and there is a drawback that the life expectancy cannot be accurately predicted.

[0006]

As described above, in the conventional technology, there is a limit in improving the installation property, the accuracy of the life estimation, the simplicity of the operation for estimating the life, and the like. That is, an object of the present invention is to provide a chemical filter and a method of using the chemical filter, and a clean room, a semiconductor manufacturing apparatus, and a fan filter, which are applications of the chemical filter, particularly having improved workability for life estimation. And

[0007]

Means for Solving the Problems In order to solve the above problems, a chemical filter of the present invention mainly has one of the following constitutions (1) and (2). That is, (1) a parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, and is configured by a plurality of filter media having different lengths in the direction in which the air flows. A chemical filter, or (2) a parallel flow filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, and the length of the air flowing direction And a filter material shorter than the length of the outer frame of the filter in the direction in which air flows.

The method of using the chemical filter of the present invention mainly has the following configuration. That is, a parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, wherein the length of the air flowing direction is the same, and the filter in the direction in which the air flows. 1 consisting of a filter medium of almost the same length as the outer frame
This is a method of using a chemical filter, wherein at least one chemical filter is used in combination with one or more of the chemical filters of (1) or (2).

The clean room of the present invention mainly has the following configuration. That is, a parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, wherein the length of the air flowing direction is the same, and the filter in the direction in which the air flows. A clean room characterized by combining one or more chemical filters of the above (1) or one or more of the chemical filters of the above (2) with one or more chemical filters composed of a filter medium having substantially the same length as the outer frame. It is.

The semiconductor manufacturing apparatus of the present invention mainly has the following configuration. That is, a parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, wherein the length of the air flowing direction is the same, and the filter in the direction in which the air flows. A semiconductor comprising a combination of at least one chemical filter of the above (1) or at least one chemical filter of the above (2) with at least one chemical filter composed of a filter medium having substantially the same length as the outer frame. Manufacturing equipment.

The fan filter of the present invention mainly has the following configuration. That is, a parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, wherein the length of the air flowing direction is the same, and the filter in the direction in which the air flows. One or more chemical filters composed of a filter medium having substantially the same length as the outer frame are combined with one or more chemical filters of (1) or (2), and further have a ventilation device. It is a fan filter characterized by the above-mentioned.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The term "chemical filter" as used in the present invention refers to a filter intended to remove gaseous pollutants in air. The chemical filter according to the present invention is excellent in estimating the life and is used in a clean room, a semiconductor manufacturing apparatus, and the like.

[0013] The chemical filter of the present invention is configured such that the flow of air passing through the filter flows substantially in parallel with the filter medium constituting the filter. The filter medium contains a functional substance that adsorbs gas components in the air inside or on its surface. The air to be treated containing the gaseous pollutant flows into the unit from the upstream side of the filter, and flows substantially parallel to the filter medium, and gradually removes the gaseous pollutant by the adsorbing action of the filter medium to reach the downstream side. In this case, the adsorbing action of the filter medium gradually loses its activity from the upstream side due to long-term use, and eventually, the expected removal efficiency of a certain level or more cannot be maintained, and the life is shortened.

FIG. 1 is an example of the chemical filter of the present invention, and is a front view as viewed from the upstream side in the air flow direction. As shown in FIG. 1, the filter medium 1 is surrounded by an outer frame 2 to constitute a filter. The flow of air passing through the filter flows between the filter media 1 in the outer frame 2 from the near side in a direction perpendicular to the paper surface. FIG. 2 shows the chemical filter of the present invention.
2 shows an example of the outline of the internal structure of a unit. FIG.
In the example, the filter has two different lengths of a long filter medium portion 4 and a short filter medium portion 5 in the length of the filter medium in the air flow direction X. In FIG. 2, the filter outer frame 2 is not drawn in order to clearly show the internal structure of the filter.

The life prediction method using the parallel flow filter of the present invention makes use of the characteristics of the parallel flow filter in which the adsorption of the filter medium gradually loses its activity from the upstream side. That is, in the example of FIG. 2, the filter medium portion 5 having a short filter medium length has a slightly shorter life than the filter medium portion 4 having a long filter medium. The life of the part 4 is predicted. As a specific method for measuring and determining the life of the chemical filter of the present invention, the concentration of the target contaminant upstream of the filter and the concentration of the target contaminant downstream of the short filter medium portion 5 are periodically measured, and the removal efficiency is determined based on the following equation. And a method for predicting and confirming the service life, and a method of calculating the life of the filter medium downstream of the long filter medium part 5 and the short filter medium part 5
There is a method of periodically measuring the concentration of the target pollutant downstream of the system and judging that a difference in the concentration level is near the end of life. Removal efficiency (%) = (1-"downstream concentration" / "upstream concentration")
× 100

Although one of the above-described chemical filters may be used alone, a method of using a plurality of chemical filters arranged side by side is very useful. That is, of the plurality of chemical filters, one uses the chemical filter of the present invention, an example of which is shown in FIG. 2, and the other filter uses the chemical filter shown in FIG. The chemical filter shown in FIG. 3 has the same type and structure of the filter medium as the filter shown in FIG. 2, and the length of the filter medium in the air flow direction is the same as that of the long filter medium portion 4 in FIG. Filter. According to the method of use of the present invention, it is possible to determine and predict the life of the long filter medium portion 5 which is the main body portion of the chemical filter of the present invention, an example of which is shown in FIG. It can be very useful. When a plurality of chemical filters are used side by side, all the filter media of one filter are configured to have the same length as the short filter media portion 5 of FIG. 2, and the other filters are combined with the long filter media portion 4 of FIG. The same life expectancy and determination can be achieved by using the same length, which is preferable.

In the filter of the present invention, an example of which is shown in FIG. 2, a space 3 is provided downstream of the short filter medium portion 5 in the filter. In the space 3, a filter medium holding frame may be arranged so as to be in contact with the filter medium downstream portion in the filter outer frame,
This is preferable for fixing the short filter medium portion 5. The pressure loss in the air flow direction of the filter medium holding frame has a pressure loss corresponding to the pressure loss difference between the long filter medium part and the short filter medium part,
This is preferable because the flow of air from the upstream side of the filter can be made uniform. The method of giving the necessary pressure loss to the filter medium holding frame is arbitrary, but the filter medium holding frame is constituted by at least a nonwoven fabric and a frame, and the nonwoven fabric is arranged at least in a portion in contact with the filter medium on the upstream side in the wind flow direction. Is simple and most preferably used in producing a filter. FIG. 4 shows an example of the filter medium holding frame used in the present invention. In FIG. 4, the filter medium holding frame includes a nonwoven fabric 6 and a frame 7.
The air flows from the upper part of the drawing as shown by the arrow in the ventilation direction. It is desirable that the pressure loss when aerating the nonwoven fabric 6 and the frame 7 has a pressure loss corresponding to a pressure loss difference between a substantially long filter medium portion and a short filter medium portion. Also, the upper surface of the frame 7 may have a wire mesh shape.
It is preferable because it can support a small amount of the nonwoven fabric 6 that impairs air permeability. In addition, it is desirable that at least one of the remaining four surfaces of the frame except for the upper and lower surfaces through which air does not ventilate, which is in contact with the long filter medium, does not have air permeability for accurate life determination. 4 excluding the upper and lower surfaces through which air is further vented
It is more preferable that the entire surface is made of a member having no air permeability, since the surface which is in contact with the long filter medium side is hardly affected. The filter medium holding frame in which the nonwoven fabric 6 is disposed on the upper surface of the frame in FIG. 4 can be used by inserting it into the space 3 in FIG.

The air on the downstream side of the filter medium is sampled for estimating and determining the service life of the filter.
Sampling can be performed separately for the short filter medium portion downstream. However, depending on the type of installation, for example, when a usage method in which a particle removal filter is arranged downstream of the chemical filter is used, accurate sampling may not be performed from the downstream surface of the filter. For this reason, it is more desirable to provide an air suction port on the downstream side of the filter medium. FIG. 5 shows an example in which an air suction port is provided on the downstream side of the filter medium. In FIG. 5, the air suction port 8 is provided on the downstream side of the short filter medium. However, a similar suction port may be provided on the downstream side of the long filter medium. In FIG. 5, the outer frame of the filter is not drawn in order to clearly show the internal structure of the filter.

A chemical filter having an air suction tube inside the unit, one end of the tube arranged inside the filter downstream side, and the other end arranged outside the filter upstream side, comprises a plurality of filters. This is more preferable because the downstream concentration can be measured from the upper surface when they are arranged side by side. FIG. 6 shows the chemical filter of the present invention. Although the filter outer frame is not shown in FIG. 6 for easy understanding of the internal structure of the filter, the sampling tube 9 is arranged on the upper surface of the filter from the downstream side of the filter medium along the inside of the filter outer frame. Is desirable without impairing the flow of air in the filter. Further, it is particularly preferable that a hole is formed in the ear portion on the upper surface of the filter outer frame and one end of the tube is disposed on the upper surface of the filter through a sampling tube in the hole so that the tube portion does not obstruct when arranged side by side.

The filter material constituting the filter of the present invention is not particularly limited as long as it has a property of adsorbing and removing gas. Examples of the filter material include activated carbon in the form of fibrous, granular, or powdered powder, and fibrous, granular, or powdered activated carbon. A substance that adsorbs a gas, such as an ion exchanger in the form of a zeolite, or a zeolite, can be used alone or in combination with a substance that becomes another aggregate. But,
In the present invention, a filter medium containing ion-exchange fibers is particularly excellent in that the gas adsorption speed is high and the life is accurately determined and predicted. More preferably, the filter medium is composed of an ion exchange fiber having an anion exchange group and / or a cation exchange group and a reinforcing fiber. The diameter of the ion exchange fiber is 15 to 100 μm from the point of having a high specific surface area.
m is preferred. More preferably 20 to 70 μm, especially 3
0 to 50 μm (dry state) is most preferred. The mode of mixing the ion-exchange polymer and the reinforcing polymer is not particularly limited,
For example, a core-sheath type fiber, a multi-core type mixed fiber and a multi-core type composite fiber having an ion exchange polymer as a main component of a sheath component and a reinforcing polymer as a core component are preferably used. In particular, the multifilament sea-island type conjugate fiber has a sufficient mechanical strength, is excellent in strength stability and the like when various forms are given, and has a large specific surface area as an ion exchanger, which is preferable. Furthermore, when a mechanical force is applied when the morphology is imparted, the multifilament sea-island composite fibers are easily fibrillated, and the specific surface area as an ion exchanger is further increased, which is extremely preferable. Examples of the reinforcing polymer include poly-α-olefin, polyamide, polyester, and polyacryl, but are not limited thereto.
Among them, poly-α-olefin is preferable because of its excellent chemical resistance in the production of ion exchange fiber. Poly-α-olefins include polyethylene, polypropylene, poly-3-
Methylbutene-1, poly-4-methylpentene-1 and the like can be mentioned, but polyethylene is preferred in view of strength and productivity. The fiber is cut into a suitable length, and then ion-exchange groups are introduced. There are a cation exchange group and an anion exchange group in the ion exchange group, and they exert their respective functions. The cut length is optional, but if the length is too short, the fibers may fall off even if it is formed, which is not preferable.If the length is too long, the uniform difference in the reaction is hindered. 0.3-5mm and even 0.3-1
The range of mm is preferred. As the anion exchange group, a strongly basic anion exchange group obtained by treating a haloalkylated product with a tertiary amine such as trimethylamine;
And a weakly basic anion exchange group obtained by treating with a secondary or lower amine such as isopropylamine, diethylamine, piperazine, morpholine, etc., and a strongly basic anion exchange group is preferred from the viewpoint of treatment performance in the present invention. . As the cation exchange group, an aminocarboxylic acid group such as a sulfonic acid group, a phosphonic acid group, a carboxylic acid group, and an iminodiacetic acid group is preferably used, and a sulfonic acid group is more preferable in view of the processing performance in the present invention.
As a specific production method of the ion-exchange fiber in the present invention, a polystyrene-based mixed or composite fiber comprising a polystyrene-based compound and poly-α-olefin is crosslinked and insoluble in a polystyrene portion with a formaldehyde source under an acid catalyst, and then A method in which an ion-exchange group is introduced by a known method is used, but the method is not limited thereto.

The structure of the filter medium of the present invention is not particularly limited as long as it is a parallel flow type. For example, the filter medium has a honeycomb structure having a substantially hexagonal cross section, a corrugated structure having a substantially triangular shape, and a prism structure having a substantially rectangular shape. , A sheet structure that is not folded at all,
A stacking structure in which these are stacked singly or in combination is exemplified. Especially the corrugated stacking structure,
It is suitable for increasing the adsorption efficiency per unit weight of the filter medium, and is excellent in that the service life can be extended and the service life can be accurately predicted.

The filter of the present invention is preferably used in a clean room, a clean booth, a semiconductor manufacturing device or other electronic device / part manufacturing device, a fan filter in which a fan and a filter are integrated, and the like.

[0023]

【Example】

(Example 1) A multifilament sea-island type ion-exchange fiber in which a sea component is provided with polystyrene having a sulfone group, and an island component is provided with polypropylene for reinforcement / division, a natural pulp and a low melting point component are provided in an outer sheath portion. The obtained polyester-based heat-sealing fiber was subjected to wet papermaking at a ratio of 60:20:20 (% by weight) to obtain a cation exchange sheet having a basis weight of about 200 g / m2. The ion exchange capacity per unit weight of this sheet is 1.
It was 6 meq / g. The ion exchange capacity is 0.1.
Approximately 1 g of the sheet in 50 ml of 1N sodium hydroxide
The mixture was shaken at 23 ° C. for 2 hours, accurately weighed 5 ml, neutralized and titrated, and calculated from the main titer and the sample weight. A roll (120 ° C.) having a corrugated surface shape in a corrugating machine (single facer for 5th stage) using the above cation exchange sheet as a substrate for a core and a substrate for a liner, a substrate for a core and a liner And so as to be in the order of the pressure roll having a flat surface shape, rotate each roll while applying pressure between the rolls, heat and pressurize the core substrate and the liner substrate, A corrugated sheet was manufactured. This corrugated sheet was cut into a size of 600 mm in width × 60 mm in length in the ventilation direction to prepare a filter medium for a filter. Further, the same corrugated structure sheet was cut into a size of 600 mm in width × 40 mm in length in the ventilation direction, and prepared as a filter material for a short filter for estimating the life. Also, a filter outer frame with a height of 610 mm, a width of 610 mm and a depth of 70 mm is made from aluminum, and the two fixed-length cut corrugated sheets are stacked and filled as shown in FIG. 2 to produce a chemical filter. did. In addition, a filter medium holding frame in which a nonwoven fabric was arranged in a portion in contact with the filter medium on the upstream side in the wind flow direction was installed downstream of the filter medium length of 40 mm. The nonwoven fabric used had a pressure loss value of 0.5 m / s at a wind speed of 60 mm for the filter medium and a 0.5 m / s wind speed at a wind speed of 40 mm for the filter medium.
The nonwoven fabric was selected so as to have a value corresponding to the difference from the pressure loss value at the time.

Using this chemical filter, an ammonia life prediction model test was performed. The test was conducted by adjusting the air adjusted to an ammonia concentration of 100 μg / m3 to a surface wind speed of 0.5 m / m3.
s to the filter for test so that the upstream of the chemical filter and the filter media length of 60 mm
The air on each downstream side of the mm portion was sampled to measure each ammonia concentration, and the removal efficiency was calculated based on the following equation. Removal efficiency (%) = (1-"downstream concentration" / "upstream concentration")
× 100 Sampling was performed by filling a collection device called an impinger with ultrapure water and allowing the target air to flow therethrough to dissolve and collect ammonia. The analysis was performed by micro-analysis using ion chromatography. Table 1 summarizes the measurement results of the removal efficiency of each of the 60 mm and 40 mm filter media lengths. At the start, the ammonia removal efficiency was almost 100% in each part, but the removal efficiency gradually decreased with time, and the removal efficiency of the 40 mm portion decreased earlier than that of the 60 mm portion. In this experiment, for example, the removal efficiency of the 60 mm portion fell below 90% four days after the 40 mm portion fell below 50%.

On the other hand, a fresh air supply apparatus for supplying a clean room was manufactured by using one new life expectancy filter used in the model experiment of this embodiment and eight normal filters shown in FIG. 3 having a filter material length of 60 mm. Adjust the surface wind velocity of the air passing through the attached filter to 0.5 m / s, and measure the removal efficiency of the filter media length of 60 mm and 40 mm of the life prediction filter attached to this device every three months. did. Furthermore, the removal efficiency when the whole apparatus was set as one unit was also measured. As a result, 2
One month later, the removal efficiency of the entire apparatus was found to be 96%, which was almost unchanged, but the filter medium length was 40 mm.
The removal efficiency was reduced to 60% in the portion indicated by, and it was possible to predict in advance that the life would be short. Based on this result, a replacement filter was immediately arranged, and after 22 months, one filter for life expectancy and eight normal filters could be replaced with new ones.

[0027]

According to the chemical filter of the present invention, by measuring the removal performance of a filter medium portion having a short length in the air flow direction, the life of another filter medium or another filter can be reduced.
Prediction and determination can be easily made without troublesome work such as removal of the filter.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state of a front of a chemical filter of the present invention.

FIG. 2 is a schematic diagram showing a state inside the chemical filter of the present invention.

FIG. 3 is a schematic diagram showing a state inside a chemical filter that can be used simultaneously with the chemical filter of the present invention.

FIG. 4 is a schematic diagram showing a state of a filter medium holding frame used in the chemical filter of the present invention.

FIG. 5 is a schematic diagram showing a state inside a chemical filter having an air suction port of the present invention.

FIG. 6 is a schematic diagram showing a state inside a chemical filter having a sampling tube of the present invention.

FIG. 7 is a graph showing the measurement results of the removal efficiency of the chemical filter of the present invention.

[Explanation of symbols]

 1: Filter medium 2: Outer frame 3: Space section 4: Long filter medium section 5: Short filter medium section 6: Non-woven fabric 7: Frame 8: Air suction port 9: Sampling tube

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[Procedure amendment]

[Submission date] August 31, 1999 (1999.8.3)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

Using this chemical filter, an ammonia life prediction model test was performed. The test was conducted by adjusting the air adjusted to an ammonia concentration of 100 μg / m3 to a surface wind speed of 0.5 m / m3.
s to the filter for test so that the upstream of the chemical filter and the filter media length of 60 mm
The air on each downstream side of the mm portion was sampled to measure each ammonia concentration, and the removal efficiency was calculated based on the following equation. Removal efficiency (%) = (1-"downstream concentration" / "upstream concentration")
× 100 Sampling was performed by filling a collection device called an impinger with ultrapure water and allowing the target air to flow therethrough to dissolve and collect ammonia. The analysis was performed by micro-analysis using ion chromatography. FIG. 7 shows the measurement results of the removal efficiencies of the 60 mm and 40 mm filter media portions. At the start, the ammonia removal efficiency was almost 100% in each part, but the removal efficiency gradually decreased with time, and the removal efficiency of the 40 mm portion decreased earlier than that of the 60 mm portion. In this experiment, for example, the removal efficiency of the 60 mm portion fell below 90% four days after the 40 mm portion fell below 50%.

Claims (14)

[Claims] 1. A parallel flow filter in which a flow of air passing through a filter flows substantially parallel along a surface of a filter medium constituting the filter, the filter comprising a plurality of filter media having different lengths in a direction in which air flows. A chemical filter. 2. The chemical filter according to claim 1, wherein a filter medium holding frame is arranged so as to be in contact with a downstream portion of the filter medium in which air of the filter medium flows. 3. The chemical filter according to claim 2, wherein the filter medium holding frame is composed of at least a nonwoven fabric and a frame, and the nonwoven fabric is arranged at least in a portion of the filter medium that is in contact with the downstream side where air flows. . 4. The chemical filter according to claim 1, wherein an air suction port is provided downstream of the short filter medium through which the air flows. 5. A filter having an air suction tube inside an outer frame of the filter, wherein one end of the tube is arranged inside a filter medium holding frame, and the other end of the tube is located outside an upstream side of the filter medium where air flows. The chemical filter according to claim 2, wherein the chemical filter is arranged so as to protrude. 6. A parallel flow type filter in which a flow of air passing through a filter flows substantially parallel along a surface of a filter medium constituting the filter, wherein air flows in the same length in a direction in which the air flows. A chemical filter comprising a filter medium shorter than a filter outer frame length in a direction. 7. The chemical filter according to claim 6, wherein a filter medium holding frame is disposed so as to be in contact with a downstream portion of the filter medium in which air of the filter medium flows. 8. The chemical filter according to claim 7, wherein the filter medium holding frame is composed of at least a nonwoven fabric and a frame, and the nonwoven fabric is arranged at least in a portion of the filter medium that is in contact with the downstream side where air flows. . 9. The chemical filter according to claim 6, wherein an air suction port is provided on a downstream side of the filter medium through which the air flows. 10. A filter having an air suction tube inside an outer frame of the filter, wherein one end of the tube is arranged inside a filter medium holding frame, and the other end of the tube is located outside an upstream side of the filter medium where air flows. The chemical filter according to claim 7, wherein the chemical filter is arranged so as to protrude. 11. A parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of a filter medium constituting the filter, wherein the length of the air flowing direction is the same, and the air flows. The chemical filter according to any one of claims 1 to 5, or the chemical filter according to any one of claims 6 to 10, wherein the one or more chemical filters are formed of a filter medium having substantially the same length as the filter outer frame in the direction. A method of using a chemical filter, wherein one or more chemical filters are used in combination. 12. A parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, wherein the air flows in the same length in the air flowing direction. The chemical filter according to any one of claims 1 to 5, or the chemical filter according to any one of claims 6 to 10, wherein the one or more chemical filters are formed of a filter medium having substantially the same length as the filter outer frame in the direction. A clean room characterized by combining one or more chemical filters. 13. A parallel flow filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, wherein the length of the air flowing direction is the same, and the air flows. The chemical filter according to any one of claims 1 to 5, or the chemical filter according to any one of claims 6 to 10, wherein the one or more chemical filters are formed of a filter medium having substantially the same length as the filter outer frame in the direction. A semiconductor manufacturing apparatus characterized by combining one or more chemical filters. 14. A parallel flow type filter in which the flow of air passing through the filter flows substantially parallel along the surface of the filter medium constituting the filter, wherein the length of the air flowing direction is the same, and the air flows. The chemical filter according to any one of claims 1 to 5, or the chemical filter according to any one of claims 6 to 10, wherein the one or more chemical filters are formed of a filter medium having substantially the same length as the filter outer frame in the direction. A fan filter comprising a combination of one or more chemical filters and further comprising a ventilation device.