JPH04309736A - Floor device for clean room - Google Patents

Abstract

PURPOSE:To facilitate a replacement of a gas adsorption filter for use in removing toxic gas generated within a clean room. CONSTITUTION:Since a gas adsorption filter is fixed to a grating 16, toxic gas can be effectively removed and a replacement of the gas adsorption filter can be easily carried out. This gas adsorption filter is comprised of grid-like structure active carbons 40 arranged and disposed within a frame 52. The active carbons 40 are formed with grid-like through-pass holes 42, so that a pressure loss of an air flow passing therethrough is low. In addition, shock absorbing materials 46 are disposed among the active carbons 40 and a dust removing filter 56 is disposed at a downstream side of it, so that the number of generated fine particles from the active carbons 40 is low.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clean room used for integrated circuits, and more particularly to a floor unit for an ultra-clean clean room suitable for manufacturing ultra-highly integrated circuit elements.

0002

[Prior Art] Generally, in semiconductor manufacturing, etc., HF, HCl, N,
In addition to H3, H2 O2, etc., various organic solvents are used. In conventional clean rooms, gas adsorption filters are installed to remove gases in order to prevent corrosion of equipment and damage to HEPA filters due to leakage of chemicals and the like. FIG. 7 shows a clean room used for manufacturing semiconductor integrated circuit devices (LSI). Fan filter units 1A and 1B are installed on the ceiling of the cleaning work area 1, and each fan filter unit 1A and 1B is equipped with a blower fan 2.
A, 2B, and high performance filters (hereinafter referred to as HEPA filters) 3A, 3B. A manufacturing device 4 is arranged in the cleaning work area 1 . Fan filter unit 1
The clean air blown out from A and 1B passes through the open floor 5 and the underfloor space 6, ascends through the maintenance areas 6A and 6B, and enters the air intake ports 1C and 1D of the fan filter unit. A part of the air from the underfloor space 6 is sent to the air conditioner 7 through the ventilation duct 6C. The air conditioner 7 consists of a mixing chamber 7A, a temperature/humidity adjustment section 7B, a blower fan 7C, a HEPA filter 7D, etc. In the mixing chamber 7A,
Air from the clean room and outside air 8 are mixed. The mixed air passes through each part of the air conditioner, is temperature and humidity conditioned, is purified, and enters the fan filter unit through the supply duct 9.

Conventionally, the open floor 5 is constructed as a metal floor with openings, and its purpose is to allow clean air supplied from the ceiling to pass through to the underfloor space 6, and also to allow workers and various types of equipment operating in the clean room to pass through. Its purpose is to serve as a support plate for the device. This open floor 5 is generally called a grating, and is manufactured as a floor unit that can withstand the weight from above and has an opening ratio suitable for various purposes.It has a standard planar dimension of 500 mm x 500 mm, and is The floor of the work area is constructed by connecting multiple pieces in succession according to the size of the area. The gratings are arranged regularly and in close contact with the cross beams laid parallel to each other in a certain direction at a pitch of 500 mm.

0004

[Problems to be Solved by the Invention] On the other hand, in clean rooms in the field of ultra-precision engineering such as semiconductors, as the microfabrication of products progresses, in addition to dust in the atmosphere, very small amounts of gases and chemical substances are becoming major sources of pollution. It's becoming obvious. As a countermeasure to this problem, a method has been considered in which an adsorbent for removing chemical substances is placed in one of the clean air circulation systems to remove harmful chemical substances from the circulating air.

For example, air for the purpose of removing harmful gas components from the outside air at the return air suction parts 1C and 1D of a fan filter unit installed on the ceiling, a part of the duct 9A of the clean room circulation system, or the outside air intake port. These harmful gases can be removed in various places such as the filter 7E in the harmonizer 7. However, the filters disposed in these circulation systems have the disadvantage that they are time-consuming to replace.

[0006] Hazardous chemical substances are mostly generated due to leakage of various chemical products, gases, etc. used in the manufacturing line from the work area, which is the product production area. Therefore, in a down-flow clean room, the most suitable place to remove the generated gas mixed in the circulating air is the suction part of the floor, that is, the open floor part.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a clean room floor unit in which gas adsorption filters can be easily replaced and maintained.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention recirculates clean air supplied through a HEPA filter on the ceiling by passing it through an open floor provided on the floor of a work area. This clean room is characterized by having a gas adsorption filter made of activated carbon in a lattice structure attached to the open floor.

[0009]

[Operation] According to the present invention, gas leaking from manufacturing equipment such as cleaning equipment in the clean air area is absorbed and removed by the gas adsorption filter with the open floor, and the gas is reliably prevented from being supplied to the clean room. Therefore, the entire clean room will not be contaminated by the gas. Furthermore, since the gas adsorption filter is provided directly under the open floor, filter replacement and maintenance are easy.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below using examples shown in the drawings. 1 and 2 show the floor structure of a clean room, in which horizontal beams (joists) 14 are arranged on support beams 10 by metal fittings 12 at the same pitch as the vertical and horizontal dimensions of gratings 16. The grating 16 is mounted and fixed on the cross beam 14 by its own weight via a vibration-proofing packing 18 made of rubber or the like.

As shown in FIG. 2, a gas adsorption filter 20 is built into the lower surface of the grating 16. Gas adsorption filter 20 can be easily replaced by removing grating 16. In FIG. 3, a lattice-structured activated carbon 40 constituting the gas adsorption filter of the present invention is shown, and the activated carbon 40 is formed in the shape of a rectangular parallelepiped as a whole. As shown in FIG. 4, the activated carbon 40 has a large number of lattice holes 4 passing through
2, and the lattice hole 42 has an opening diameter l = 0.7 to 1.2 mm.
, wall thickness t=0.2 to 0.4 mm. The activated carbon 40 is not limited to a lattice structure, but may have a honeycomb structure.

A plurality of activated carbons 40 configured as described above are arranged in a line in an inner frame 44 made of expanded polystyrene shown in FIG. A polyester fiber cushioning material 46 is placed between each activated carbon 40 to prevent the activated carbons 40 from coming into direct contact with each other. Furthermore, polyester fiber protective sheets 48 and 50 are provided on the upper and lower surfaces of the activated carbon 40. Furthermore, the activated carbon 40 configured in this way has a lower frame 52.
There is a lower expanded metal 54, a coarse filter 56,
The upper expanded metal 58 and the upper frame 60 are stacked and integrated with a bolt 62 to form a gas adsorption filter.

FIG. 6 shows another embodiment of the present invention, in which the gas adsorption filter 20 is suspended from the cross beam 14 using a suspension fitting 24 provided at the end thereof. The gas adsorption filter 20 is attached separately from the grating 16 by sharing the cross beam 14, so even when the grating 16 is removed, the gas adsorption filter 20 can be left as it is, and by removing the grating 16, it can be removed from the floor as it is. It is possible to pull up and remove the gas adsorption filter 20. In addition, a gas adsorption filter 2 is installed from the bottom of the floor.
0, the gas adsorption filter 20 can be easily removed by lifting one end of the suspension fitting 24 and pulling it diagonally upward, the other end comes off the cross beam 14, and then pulling it diagonally downward.

Gas adsorption filters are made of various materials such as pellets, honeycombs, and non-woven fabrics, but in all cases, the adsorbent is held by a holding material that prevents the adsorbent from falling off.
Needless to say, it is protected. However, in order to reduce the blowing power, it is important to select a material with a resistance of several millimeters of water column (maximum 5 mm Aq) or less when the air flow passes through the floor surface.

[0015] Furthermore, there may be cases where no gas adsorption filter is attached to the floor in an area where a gas adsorption filter is not required. In this case, it is desirable to install an air resistance element of the same level as the gas adsorption filter using a similar method. In this way, adding air resistance at the bottom of the floor is a negative factor in terms of air flow resistance and blowing power, but by having an appropriate amount of air resistance across the entire floor surface, pressure equalization occurs in the work area. This has the advantage that abnormal phenomena such as lateral air flow within the work area are less likely to occur. This means that the current floor design, which prevents sideways airflow by changing the floor opening ratio, becomes unnecessary. Conventionally, floor openings have been designed to prevent cross-overs in work areas through simulations and experiments, which requires an extremely large amount of effort.The application of the present invention will eliminate the need for complicated opening ratio designs, which will lead to a reduction in design man-hours. It is also highly efficient.

[0016]

As explained above, the present invention effectively removes harmful gases generated in a clean room by using an open-bed gas adsorption filter, prevents corrosion of HEPA filters, and prevents boron compounds from scattering from the filter material. Therefore, the yield of integrated circuit devices can be improved and performance deterioration can be prevented.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a clean room floor unit according to the present invention.

[Fig. 2] Fig. 2 is a sectional view of a clean room floor unit according to the present invention.

[Fig. 3] Fig. 3 is a perspective view of the lattice structure-shaped activated carbon of the present invention.

[
FIG. 4 is an enlarged perspective view of activated carbon of the present invention

[Figure 5] Figure 5
is an exploded perspective view of the gas adsorption filter of the present invention.

[Figure 6] Figure 6
are characteristic diagrams showing the respective pressure losses when the aperture ratio of the activated carbon of the present invention is changed.

[Figure 7] Figure 7 is a schematic configuration diagram showing an example of a conventional clean room.

[Explanation of symbols]

14...Horizontal beam 16...Grating 20...Gas adsorption filter 40...Lattice structured activated carbon

Claims (3)

[Claims] Claim 1: A clean room in which clean air supplied through a HEPA filter on the ceiling is recirculated by passing through an open floor provided on the floor of the work area, the open floor being made of activated carbon in a lattice structure. A clean room floor unit featuring a built-in gas adsorption filter. Claim 2: In a clean room in which clean air supplied through a HEPA filter on the ceiling is recirculated by passing through an open floor provided on the floor of the work area, a lattice-structured activated carbon is placed directly under the open floor. A clean room floor unit characterized by a detachable gas adsorption filter. Claim 3: A claim characterized in that the gas adsorption filter is supported by a cross beam that supports the open floor, has approximately the same dimensions as one unit of the open floor, and is configured to correspond to the open floor. The clean room floor unit described in item 2.