JP2002243233A - Air-cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-cleaning device capable of forming the cleaner space by equalizing air volume and forming equal descending laminar flow. SOLUTION: In an air-cleaning device with a fan filter unit installed at the upper part of a space surrounded by partitions on all sides for blowing out clean air from the blowout face of the unit toward the space and keeping the inside of the space clean, it has such a constitution that a perforated plate having many openings is arranged in the space to allow clean air to flow toward the lower part of the space through the perforated plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purifying apparatus, and more particularly to an air purifying apparatus in which a wafer handling space such as a semiconductor processing apparatus has a locally high-purity space.

[0002]

2. Description of the Related Art As the performance and integration of semiconductor devices are further improved, clean rooms are required to have higher and higher cleanliness, and the costs of equipment and maintenance thereof are steadily increasing. Therefore, in order to reduce the cost required for the clean room, and to make the atmosphere in contact with the wafer even more clean and to be able to respond to the high performance and high integration of devices, the wafer handling space of the processing equipment is locally highly cleaned. Place a local air purifier and
The transfer of wafers between these processing units is performed by using a SMIF pod or F
Attention has been paid to a mini-environment system in which the device is housed in a closed container such as an OUP.

FIG. 6 shows an example of such a local air cleaning device. The air cleaning device 1 is composed of a fan filter unit that blows clean air and a partition that separates a clean space. Specifically, a cover 4 is attached to four side surfaces of a frame including a support 2 and a support frame 3. The fan filter unit 5 is fixed on the support frame 3 with the blowing surface facing downward. The clean air blown from the fan filter unit 5 flows downward, and the gas flow keeps the space inside the frame in a clean atmosphere with few particles.

In this air purifying apparatus, for example, as shown in a front view (A) and a rear view (B) of FIG. 5, a space between a semiconductor processing apparatus 10 and a pod stage 11 on which a pod 12 is mounted. That is, it is incorporated in the space where the wafer transfer robot is installed. The covers 4 on the pod stage side and the processing chamber side have openings 13 and 1 for wafer transfer.
4 are formed. With such a configuration, clean air is always flowing in the space where the wafer is transferred, so that particle contamination on the wafer can be prevented.

[0005]

However, while the present inventors have studied the improvement of cleanliness, it has become clear that the conventional air cleaning apparatus has various problems. That is, there is a problem that a turbulent flow is generated due to the formation of air pockets under the support frame 3 of the apparatus because the air volume is not obtained, and the air flow flies under the support frame, so that a uniform descending surface flow cannot be obtained. It became clear. The turbulence of the airflow causes the particles to wind up and contaminate the wafer. Therefore, if the degree of integration is further increased, it becomes a serious problem.

For this reason, the support frame has been removed, and the structure of the apparatus for supporting the side of the unit has been studied. However, due to the structure of the fan filter unit, there is a portion without blowout at the periphery of the bottom of the unit. It was found that turbulence occurred. This problem also occurs when a plurality of fan filter units are attached, and the air flow in the entire apparatus varies.

In addition, there is a problem that the air flow is strong at the center of the blow-out surface of the fan filter unit 5 and weak at the periphery, resulting in a variation in the air flow as a whole. Although this problem can be solved to some extent by increasing the distance between the fan and the filter in the fan filter unit,
There is a new problem that the entire device becomes large.

[0008] Under the circumstances described above, the present invention solves the above-mentioned problems, and provides an air purifying apparatus capable of forming a more clean space by making the air flow more uniform to form a uniform descending surface flow. The purpose is to do. It is another object of the present invention to provide an air purifying apparatus with a more compact fan filter unit.

[0009]

According to the air purifying apparatus of the present invention, a fan filter unit is installed above a space surrounded on all sides by a partition, and clean air is blown from the blowing surface of the unit toward the space. In the air purifying apparatus for blowing and keeping the inside of the space clean, a perforated plate having a large number of openings is arranged in the space, and the clean air is caused to flow toward the lower part of the space through the perforated plate. It is characterized by the following. In this way, by attaching the perforated plate to the entire surface of the gas flow path at a predetermined distance from the outlet of the fan filter unit, even if turbulence occurs at the peripheral portion of the fan filter unit outlet surface or the lower portion of the support frame, the perforated plate is not affected. The pressure on the plate is equalized, and a uniform downward surface flow can be formed downstream of the perforated plate. As a result,
The soaring of the particles is prevented, and the particles mixed in for some reason can be discharged out of the space along the descending surface flow, so that a particle-free and highly clean atmosphere can be obtained.

The perforated plate of the present invention can be attached to an existing cleaning device, and can be detachably attached. Therefore, the distance from the blowing surface, aperture ratio, hole position,
By appropriately selecting the pore size, it is possible to meet all the required conditions. Further, it is not necessary to adjust the air flow rate by increasing the distance between the fan and the filter in the fan filter unit as in the conventional device, and it is possible to realize a compact fan filter unit, and as a result, it is possible to reduce costs. Become.

In the present invention, it is preferable that the distance between the blowing surface and the perforated plate is 80 mm or more. 80
mm or less, when the wind speed changes or the width of the support frame, etc., the pool area increases, and in some cases, a uniform flow may not be obtained.
For example, a uniform airflow can be formed at a wind speed of 0.3 to 0.6 m / s. In addition, usually, 5
It is set to about 00 mm or less.

The aperture ratio of the perforated plate is 30 to 75%.
The hole diameter of the opening is preferably 2 to 10 mm. By keeping the opening ratio and the hole diameter within this range, the uniformity of the descending surface flow downstream of the perforated plate is further improved.

[0013]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic perspective view (A) and a cross-sectional view (B) showing an example of the air cleaning device of the present invention. As shown in FIG.
Is a frame composed of the support 2 and the support frame 3, a cover (partition) 4 surrounding four sides of the frame, a fan filter unit 5 fixed on the support frame 3, and a predetermined interval from the fan filter unit 5. Perforated plate 6
Consists of

The perforated plate 6 is formed of a stainless plate or the like having such a thickness as not to bend and having a large number of openings formed thereon. The perforated plate 6 is formed at a predetermined interval from the gas blowing surface of the fan filter unit to form a frame. It is attached. Here, the aperture ratio of the perforated plate, the diameter, the number, the position, and the like of the holes may be appropriately determined according to the required cleanliness, wind speed, and the like.
A hole diameter of 0 to 75% and a hole diameter of 2 to 10 mm are suitably used, for example, they are arranged in a lattice or staggered pattern. The mounting position of the perforated plate may be determined according to the wind speed and the width of the support frame, but it is preferable to mount the perforated plate at a distance of 80 mm or more from the blowout surface. Can be suppressed. The perforated plate is
It may be attached detachably or movably in the height direction.

The fan filter unit 5 of the present invention is constructed by integrally assembling a blower fan 5a composed of an axial fan such as a turbo fan or a plug fan and a high-performance filter 5b such as a HEPA filter or an ULPA filter.
The filter is provided downstream of the fan motor driven blower fan. Although the cover 4 is not particularly limited, when the apparatus shown in FIG. 1 is incorporated in the wafer transfer space shown in FIG. 5, a stainless steel plate having a thickness of about 1.2 to 2 mm is usually provided on the pod stage side. A similar stainless steel plate or a vinyl chloride resin plate having a thickness of about 5 mm is used on the apparatus side.

When the fan filter unit 5 is operated in this installed state, air is sucked in from the outside of the apparatus by the blower fan 5a and blown out toward the perforated plate 6 through the filter 5b. At this time, dust and fine particles contained in the air are removed by the filter 5b, and the purified air is blown into the inside of the device. Here, the fan filter unit 5
The management wind speed of the clean air from the air outlet is usually 0.3m
/ Sec to 0.6 m / sec, which is appropriately determined according to the required performance. The blown-out clean air does not become a uniform airflow because a turbulent flow is generated below the support frame 3.
On the downstream side of the perforated plate, a uniform descending surface flow is obtained, and the space surrounded by the cover 4 can be highly purified.

The fact that a uniform descending surface flow can be formed by installing a perforated plate will be described with reference to the results of airflow analysis. In this airflow analysis, the wind speed from the outlet of the fan filter unit was 0.5 m / sec, and the mounting position of the perforated plate was 100 mm from the outlet surface. Further, as shown in FIG. 2, the openings of the perforated plate were formed with openings having a hole diameter of 8.74 mm at a pitch of 10 mm, and the opening ratio was 57%. FIG. 3 shows the analysis results. In FIG. 3, (A) is a wind speed vector diagram in the device, and the length of the vector indicates the strength of the wind speed. (B) is a stream diagram of particles. For comparison, a similar analysis was performed for a conventional apparatus in which a perforated plate was not arranged, and this was shown in FIG.

When there is no perforated plate, as shown in FIG.
It can be seen that the wind speed is strong at the center of the device and weak at the end, causing variations in the wind speed. Further, it can be seen that the airflow soars due to the accumulation of air at the support frame portion, and a uniform descending surface flow cannot be obtained. Therefore, the amount of particles that stay in the space due to the airflow increases, and the probability of wafer contamination increases. On the other hand, in FIG. 3 where the perforated plate is installed, almost the same wind speed is obtained at the center and the end, and even if turbulence occurs at the end of the device between the blowing surface and the perforated plate, the flow is downstream of the perforated plate. It can be seen that the flow is made uniform and a uniform descending surface flow is formed. Thus, by arranging the perforated plate, an extremely clean space can be created.

When the air purifying apparatus of the present invention is incorporated in another processing apparatus or the like, it goes without saying that the partition walls and other members may also be used as members of the processing apparatus. Further, in FIG. 1, the horizontal cross-sectional area of the fan filter unit and the space to be cleaned are the same. And a uniform descending surface flow can be formed.

In the above embodiment, the case where the processing apparatus and the like are locally highly purified has been described. However, the present invention can be applied to the entire clean room. Furthermore, not only the clean room or the local cleaning device for semiconductor manufacturing, but also various clean rooms and local cleaning devices such as a biological clean room, a biohagard countermeasure facility, a refrigeration unit of a marine container ship, a clean room and a delivery room of a hospital, and the like. It is also possible to apply to.

[0021]

As described above, according to the present invention, that is, by attaching the perforated plate to the entire lower surface at a certain distance from the blowout surface of the fan filter unit, the peripheral portion of the blowout surface or below the support frame can be obtained. Even if turbulence occurs, the airflow under the perforated plate is made uniform,
An excellent effect that the fan filter unit can be made compact can be achieved. Furthermore, since it can be attached to existing cleaning equipment and the perforated plate is detachably provided, the degree of freedom of installation is high, and the distance from the outlet, the aperture ratio of the perforated plate, the hole diameter, the position, etc. are changed. Can be retrofitted, and can correspond to all setting conditions of each device. Further, by providing the perforated plate, the fan filter unit can be made compact, which contributes to cost reduction of the unit.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an air cleaning device of the present invention.

FIG. 2 is a schematic diagram showing an example of the arrangement of holes in a perforated plate.

FIG. 3 is a schematic diagram showing an airflow state and a flow of particles according to the present invention.

FIG. 4 is a schematic diagram showing an airflow state and a flow of particles inside a conventional apparatus.

FIG. 5 is a schematic view showing an example of installation of the air cleaning device of the present invention.

FIG. 6 is a schematic diagram showing a conventional air cleaning device.

[Explanation of symbols]

 1 air purifier, 2 columns, 3 support frame, 4 cover, 5 fan filter unit, 5b filter, 5a fan, 6 perforated plate, 10 processing unit, 11 pod stage, 12 pod, 13, 14 opening.

Claims (3)

[Claims] 1. A fan filter unit is installed above a space surrounded on all sides by a partition, and clean air is blown from a blowing surface of the unit toward the space to keep the inside of the space clean. The air purifying apparatus according to claim 1, wherein a perforated plate having a large number of openings is arranged in said space, and clean air flows toward a lower portion of said space through said perforated plate. 2. The air purifying apparatus according to claim 1, wherein a distance between the blowing surface and the perforated plate is set to 80 mm or more. 3. The air cleaning apparatus according to claim 1, wherein the aperture ratio of the perforated plate is 30 to 75%, and the hole diameter of the opening is 2 to 10 mm.