JP2000337675A - Clean room device of low dew point - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clean room device of a low dew point without elevating the dew point by the inflow of outdoor air. SOLUTION: A clean room device 1 of a low dew point is equipped with an air feeding surface 12, on which fan filter units(FFU) 20 are arranged, an air discharging surface 13 for discharging air in a clean room 11, air returning routs 14, 15, 16 for returning air from the air discharging surface 13 to the air feeding surface 12 through the routs at the outside of the clean room and a cooling coil 35 provided in the air returning routs. In such a device, at least an atmospheric pressure at the downstream side of the cooling coil 35 in the air returning routs 15, 16, 14 is controlled so as to be equal to or higher than the outside atmospheric pressure of the clean room device 1 whereby the inflow of air from the outside of the clean room device 1 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a clean room apparatus having a low dew point.

[0002]

2. Description of the Related Art A clean room in which a high-performance filter such as a HEPA filter or an ULPA filter is used to minimize the amount of suspended dust in a room is widely used, for example, in a precision machine, a semiconductor product manufacturing room, an operating room, and the like. I have. As a method of this clean room, a fan filter unit (hereinafter referred to as “FFU”) equipped with a fan and a high-performance filter is arranged on the ceiling surface (air supply surface) of the clean room to supply air downward into the clean room. ,
The so-called FFU system in which the air exhausted through the floor surface (exhaust surface) of the clean room is returned to the back of the ceiling via the return air duct, and the air cleaned by the FFU is supplied from the ceiling surface (air supply surface) into the clean room. Is known.

[0003] This FFU type clean room apparatus is
Negative pressure is applied to the space above the ceiling by the suction force of the fan, and the pressure is lower than in the clean room.
A high-performance filter is installed on the ceiling surface, and high-pressure air is supplied to the inside of the clean room with a single large fan so that high-pressure air can be supplied to and circulated in the clean room without the contamination sources existing in the ceiling from flowing into the clean room. Compared to methods,
The sealing performance around the filter can be extremely relaxed. At the same time, the FFU-type clean room equipment has a high effect of reducing energy consumption, can easily follow changes in production layout, and can be constructed in a short construction period.
Further, there is an advantage that individual control is easy. For this reason,
FFU type clean room apparatuses are widely used.

[0004]

On the other hand, clean room apparatuses having a low dew point, which performs dehumidification in addition to cleaning, have become widespread, although the required cleanliness is relatively low. In the case of such a clean room apparatus having a low dew point, when moist air flows into the system from outside the clean room apparatus, the dew point temperature rises, and the apparatus becomes useless. For example, 0.5 for air with a dew point temperature of -50 ° C.
%, The dew point temperature rises by about 14 ° C. If the above-mentioned FFU method is applied to a clean room apparatus as it is, the pressure in the space above the ceiling decreases due to the operation of the fan. If there is a gap in the wall or the like, outside air enters through the gap and the dew point temperature rises. In particular, because the space above the ceiling is large, unlike the return air duct, the amount of air passing through the ceiling is large, and the effect of outside air that flows into the small gap increases the dew point temperature very much. For example, when a clean room is a production facility Have obstacles such as a significant decrease in yield.

On the other hand, the gap is filled with a sealant or the like,
It is conceivable to prevent such humid air from flowing into the ceiling. However, in the manufacture of semiconductors and the like, the use of a sealant may be restricted due to organic contamination or the like. In addition, the cost required for the construction becomes enormous. Production processes in low dew point environments include electronic products such as lithium batteries and pharmaceutical and food processes, but with the increasing quality and technology of products, there is an increasing demand for cleaner rooms. .

Accordingly, it is an object of the present invention to provide a low dew point clean room apparatus in which the dew point does not rise due to the inflow of outside air by applying the excellent FFU method as a clean room type to a low dew point facility. .

[0007]

In order to achieve this object, according to the first aspect, an air supply surface on which a fan filter unit is disposed, an exhaust surface for exhausting air in a clean room, and A clean room apparatus comprising a return air path for returning air from an exhaust surface to an air supply surface outside, and an air resistance member provided in the return air path, wherein at least a downstream side of the air resistance member in the return air path. A pressure means for making the pressure on the side equal to or higher than the external pressure of the clean room device is provided.

[0008] In the clean room apparatus of the first aspect, the air resistance member includes, for example, a cooler such as a cooling coil provided in a return air path for compensating heat generation of equipment in the clean room. Another example is a resistance plate provided in the return air path to keep the air volume balance in the room constant. The return air path is, for example, a return air duct for returning the air exhausted from the exhaust surface of the clean room to the air supply surface. The return air path is usually arranged outside the clean room, but may be inside the clean room. That is, in the clean room apparatus according to the first aspect, the return air path for returning the air from the exhaust surface to the air supply surface outside the clean room is a path defined by the atmosphere in the clean room maintained at a predetermined cleanliness. good.

According to the first aspect of the present invention, air exhausted from the clean room via the exhaust surface is supplied to the clean room from the air supply surface through the return air path. At this time, the air pressure at least downstream of the air resistance member in the return air path is made equal to or higher than the external air pressure of the clean room device by the pressurizing means. In this case, there is no fear that air flows from outside the clean room device into the return air path.

[0010] In the clean room apparatus of the first aspect, the pressurizing means is, for example, a fan for blowing return air downstream of the air resistance member, as described in the second aspect. When this fan is operated, the area downstream of the fan in the return air path is pressurized and becomes equal to or higher than the external pressure of the clean room device, and air flows in from outside the clean room device. Disappears.

According to a third aspect of the present invention, the return air path includes an air supply space provided to cover the air supply surface with a predetermined width outside the clean room of the air supply surface, and the exhaust gas passage. An exhaust space provided so as to cover the exhaust surface with a predetermined width outside the clean room, and a return air duct connecting the air supply space and the exhaust space, and the air pressure in the air supply space is made uniform. A fan may be provided. Then, it is possible to make the entire air pressure in the air supply space equal to or higher than the external air pressure of the clean room device. Also,
The airflow distribution in the clean room is suitably maintained, and it is possible to meet the demand for advanced cleaning of low dew point equipment.

According to a fourth aspect of the present invention, the return air passage includes an air supply space provided to cover the air supply surface with a predetermined width outside the clean room of the air supply surface, and the exhaust air passage. An exhaust space provided so as to cover the exhaust surface with a predetermined width outside the clean room, and a return air duct connecting the supply air space and the exhaust space. A fan may be provided. By doing so, it is possible to maintain a positive pressure even in the space between the exhaust means on the upstream side of the pressurizing means and the pressurizing means, and to more reliably prevent external air from being mixed into the low dew point air. Can be prevented.

The air resistance member may be a cooling coil, and the pressurizing means may supply the return air to the cooling coil evenly. Thereby, the return air can be adjusted to a desired temperature in the return air path.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram illustrating a schematic configuration of a clean room device 1 according to an embodiment of the present invention.

Inside the building 10, there is a clean room 11
Are formed. Although not shown, clean room 1
In 1, various devices are installed according to the purpose. In this embodiment, the ceiling surface of the clean room 11 is formed on an air supply surface 12, and the floor surface of the clean room 11 is formed on an exhaust surface 13 made of, for example, a punching plate or a grating floor. Above the air supply surface 12 (the space above the ceiling) is formed in an air supply space 14 provided so as to cover the air supply surface 13 with a predetermined width outside the clean room 11 (upper side in the illustrated example). The lower part of the exhaust surface 13 (the space under the floor) is located outside the clean room 11 (the lower side in the illustrated example).
Exhaust space 1 provided so as to cover 3 with a predetermined width
5 is formed. Inside the building 10, beside the clean room 11, these air supply space 14 and exhaust space 1
The return air duct 16 which connects the 5 is formed. The exhaust space 15, the return air duct 16, and the supply space 1
4 constitutes a return air path for returning air from the exhaust surface 13 to the air supply surface 12 outside the clean room 11.

A plurality of FFUs 20 are installed on the air supply surface 12 by being mounted on a lattice-shaped ceiling frame. In this embodiment, the FFUs 20 are arranged on the entire upper surface of the air supply surface 12. . Each of these FFUs 20 has a configuration in which an air supply fan 22 is mounted on a high-performance filter 21 such as a HEPA filter or an ULPA filter, and clean air filtered by the high-performance filter 21 by the operation of the air supply fan 22. The clean room 11 is supplied by discharging downward from the entire supply surface 12.

The control of each FFU 20 is, for example, as follows. That is, the operation of the air supply fan 22 provided in each FFU 20 is controlled by the differential pressure gauge 25 and a controller (not shown). The differential pressure gauge 25 is a pressure sensor 26
A difference between the air pressure in the clean room 11 detected by the pressure sensor 27 and the air pressure in the air supply space 14 detected by the pressure sensor 27 at a position distant from a blower fan 36 described later is measured by a controller (not shown). 25 so as to maintain the differential pressure measured by the F.25 in a predetermined range.
The air supply fans 22 of the FU 20 are individually controlled. The pressure in the clean room 11 is always about several tens Pa (for example, about 20 Pa) than the pressure in the air supply space 14.
I am trying to be higher. The operation control of the air supply fan 22 is performed by changing the frequency by, for example, an inverter. The maintenance of the atmospheric pressure in the clean room 11 will be described later.

In the air supply space 14, the air blown from the return air duct 16 to the air supply space 14 is distributed evenly throughout the air supply space 14 so as to make the air pressure in the air supply space 14 uniform. Auxiliary fan 28 is provided.

In the illustrated embodiment, exhaust fans 30 are arranged on the entire lower surface of the exhaust surface 13, and the air in the clean room 11 is directed downward from the entire exhaust surface 13 to the exhaust space 15 by the operation of the exhaust fans 30. Is forcibly ejected. In the exhaust space 15,
An auxiliary fan 31 for blowing air exhausted from the clean room 11 to the exhaust space 15 toward the return air duct 16 is provided.

The return air duct 16 is provided with a cooling coil 35 as cooling means, and a blowing fan 36 is provided upstream of the cooling coil 35 (below the cooling coil 35 in the illustrated example). Have been. On the discharge side of the blower fan 36, a hopper 37 for uniformly supplying air to the cooling coil 35 is mounted. By operating the blower fan 36, the air in the exhaust space 15 is blown to the air supply space 14 through the return air duct 16, and the air is cooled to a desired temperature by the cooling coil 35 at this time. Heat generated by various devices (not shown) installed in the clean room 11 is compensated, and air at a constant temperature is supplied into the clean room 11. Cooling coil 35
Does not cause condensation or the like on the surface and does not change the humidity in the air blown through the return air duct 16.

The operation of the blower fan 36 is controlled by a differential pressure gauge 40.
And is controlled by a controller (not shown). The differential pressure gauge 40 measures the pressure on the discharge side of the blower fan 36 detected by the pressure sensor 41 and the pressure on the suction side of the blower fan 36 detected by the pressure sensor 42, and a controller (not shown) measures the difference. The operation of the blower fan 36 is controlled based on the pressure difference between the discharge side and the suction side of the blower fan 36 measured by the pressure gauge 40, and the discharge side of the blower fan 36 is controlled so that air outside the system does not enter the return air path. The pressure difference on the suction side is maintained properly. The operation control of the blower fan 36 is performed by, for example, changing the frequency by an inverter.

In the present embodiment, a region downstream of the cooling coil 35 in the return air path constituted by the exhaust space 15, the return air duct 16 and the air supply space 14 (that is, in this embodiment, Between the area downstream of the cooling coil 35 in the air duct 16 and the air supply space 14).
The dehumidified air (outside air) is supplied from the air supply duct 45. That is, the end face of the dehumidifying rotor 48 which is arranged upstream of the air supply duct 45 and rotates is formed by the dehumidifying area 47 and the regeneration area 48.
The end face of the dehumidification rotor 48 moves alternately between the dehumidification area 47 and the regeneration area 48 with rotation. High-temperature air heated by a heater 49 is supplied to the regeneration area 48 by operation of a fan 50, and a heat exchanger 51 such as a cooling coil is supplied to the dehumidification area 47.
The outside air cooled to a desired temperature by the operation of the fan 52 is supplied. Then, the outside air is dehumidified by passing through the dehumidification rotor 48 in the dehumidification area 47, and the air thus dehumidified and cooled to a desired temperature is removed.
Through the air supply duct 45, a region downstream of the cooling coil 35 in the return air path (that is, in this embodiment, between the region downstream of the cooling coil 35 in the return air duct 16 and the air supply space 14). Supplied. As a result, the dehumidified and cooled air is supplied to the clean room 11 in a clean state by the FFU 20, and the inside of the clean room 11 has a low dew point atmosphere. Fan 5
By supplying the outside air from the air supply duct 45 by the operation of 2, the region of the return air duct 16 downstream of the cooling coil 35 and the air supply space 14 are pressurized. Although not shown, an amount of air corresponding to the outside air taken in by the operation of the fan 52 is exhausted to the outside of the building 10.

The operation of the blower fan 52 is controlled by a differential pressure gauge 55 and a controller (not shown). The differential pressure gauge 55 measures the difference between the air pressure inside the clean room 11 detected by the pressure sensor 56 and the air pressure outside the clean room device 1 detected by the pressure sensor 57, and a controller (not shown) controls the differential pressure gauge 55. The fan 52 is controlled so that the measured differential pressure is maintained within a predetermined range. Thus, the pressure in the clean room 11 is always higher than the pressure outside (outdoor pressure) of the clean room apparatus 1. in this case,
The difference between the pressure in the clean room 11 and the pressure outside (outside) the clean room device 1 is controlled so that the pressure in the clean room 11 is higher than the pressure outside. That is, the pressure in the clean room 11 is
2 is controlled by the outside air intake amount. The operation of the fan 52 is controlled by, for example, changing the frequency by an inverter.

Now, in the clean room apparatus 1 configured as described above, the air in the clean room 11 is discharged downward from the exhaust surface 13 and exhausted to the exhaust space 15. In this case, the exhaust fan 30 is operated as needed to remove the air in the clean room 11 to the exhaust space 15.
Forcibly exhaust air. Further, when the static pressure in the clean room 11 is uneven, the air in the clean room 11 is averaged from the entire exhaust surface 13 by increasing the operation of the exhaust fan 30 corresponding to a portion where the static pressure is low. Exhaust.

The air exhausted from the clean room 11 to the exhaust space 15 is then blown toward the return air duct 16. At that time, in the clean room apparatus 1 of this embodiment, the air exhausted from the clean room 11 to the exhaust space 15 is directed to the return air duct 16 by the operation of the auxiliary fan 31 provided in the exhaust space 15. The air can be blown without delay.

Thus, the return air duct 16 is removed from the exhaust space 15.
Is blown upward in the return air duct 16 by the operation of the blower fan 36, and is cooled by the cooling coil 35 at that time, whereby various devices installed in the clean room 11 are installed. (Not shown) heat is compensated. The air thus conditioned is then blown from the return air duct 16 to the air supply space 14, and
After the operation of the air supply fan 22 provided in the FU 20, the air becomes clean air filtered by the high-performance filter 21.
Clean room 11 is discharged downward from air supply surface 12
Is supplied inside. This makes it possible to circulate and supply clean air with a low dew point into the clean room 11.

In the clean room apparatus 1 according to this embodiment, the outside air cooled to a desired temperature by the heat exchanger 51 and dehumidified by the dehumidification rotor 48 is supplied to the fan 5.
2, the air pressure in the area downstream of the cooling coil 35 in the air supply space 14 and the return air duct 16 is always equal to the air pressure outside the clean room apparatus 1. Alternatively, it is maintained at a higher pressure. Therefore, the air supply space 14
In a region downstream of the cooling coil 35 in the inside or the return air duct 16, there is no fear that air (outside air that has not been dehumidified or temperature-controlled) flows in from outside. Therefore, clean air with a low dew point can be supplied into the clean room 1. Further, in the clean room apparatus 1 of this embodiment, the static pressure of the entire air supply space 14 can be made constant by operating the auxiliary fan 28 provided in the air supply space 14.

Although an example of the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the clean room apparatus 1 according to the embodiment shown in FIG. 1, an example in which the exhaust fan 30 is mounted on the entire exhaust surface 13 (floor surface) of the clean room 11 has been described.
The air in the exhaust space 1 is passed through the exhaust surface 13 without resistance.
5, the number of exhaust fans 30 can be reduced or omitted. Also, an example in which the FFUs 20 are arranged on the entire air supply surface 12 has been described.
The number of FFUs 2 to be installed is arbitrary. For example, the FFUs 20 can be arranged with appropriate thinning. Although FIG. 1 illustrates an example in which the ceiling surface of the clean room 11 is formed on the air supply surface 12 and the floor surface is formed on the exhaust surface 13,
The positions of the air supply surface 12 and the exhaust surface 13 are not limited to these. For example, the air supply surface 12 and the exhaust surface 13 may be inverted, or the air supply surface 12 and the exhaust surface 13 may be formed on the wall surface of the clean room 11. In addition, the auxiliary fans 28 and 3
1 can be omitted, but when the capacity of the air supply space 14 or the exhaust space 15 is large, the auxiliary fans 28, 31
Should be installed. The number of the auxiliary fans 28 and 31 is not limited to one, and may be two or more. The installation positions of the auxiliary fans 28 and 31 are determined by a known calculation method in order to make the static pressure in the air supply space 14 and the exhaust space 15 uniform. And the number of installations can be determined. Further, the air supplied into the system from the air supply duct 45 may be all outside air (all-outside air dry air supply), or may be recycled by taking in return air from the clean room 11.

[0029]

According to the first to fifth aspects, it is possible to supply dehumidified clean air into the clean room without worrying about inflow of air from outside the clean room apparatus.
For this reason, there is no need to apply a special seal to the return path,
It is possible to create an environment that is optimal for the manufacture of semiconductor devices free from organic contamination and the like. In particular, according to the third aspect, the air pressure in the entire air supply space can be made uniform, and according to the fourth aspect, the air exhausted from the clean room to the exhaust space can be blown to the return air duct without interruption. . These claims 3 and 4 are particularly effective when the volume of the clean room is large.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a clean room apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clean room apparatus 10 Building 11 Clean room 12 Air supply surface 13 Exhaust surface 14 Air supply space 15 Exhaust space 16 Return air duct 20 FFU 25, 40, 55 Differential pressure gauge 28, 31 Auxiliary fan 30 Exhaust fan 35 Cooling coil 36 Ventilation fan 48 Reduction Wet rotor 51 Cooling coil 52 Fan

Claims (5)

[Claims] 1. An air supply surface on which a fan filter unit is disposed, an exhaust surface for exhausting air in a clean room, a return air path for returning air from the exhaust surface to the air supply surface outside the clean room, and a return air path. A clean room apparatus provided with an air resistance member provided in the clean room apparatus, wherein the air pressure at least downstream of the air resistance member in the return air path is equal to or higher than the external air pressure of the clean room apparatus. A clean room device with a low dew point, characterized by providing a pressurizing means. 2. The low dew point clean room apparatus according to claim 1, wherein the pressurizing means is a fan that blows return air downstream of the air resistance member. 3. The return air path includes an air supply space provided to cover the air supply surface with a predetermined width outside the clean room on the air supply surface, and the exhaust air space outside the clean room on the exhaust surface. An exhaust space provided to cover the surface with a predetermined width, a return air duct connecting the air supply space and the exhaust space, and a fan for equalizing the air pressure in the air supply space. The low-dew-point clean room apparatus according to claim 1 or 2, wherein: 4. The return air path includes an air supply space provided to cover the air supply surface with a predetermined width outside the clean room on the air supply surface, and the exhaust air space outside the clean room on the exhaust surface. An exhaust space provided so as to cover the surface with a predetermined width; a return air duct connecting the air supply space and the exhaust space; and a fan for equalizing the air pressure in the exhaust space. The low dew point clean room apparatus according to any one of claims 1, 2, and 3. 5. The air resistance member is a cooling coil,
5. The low dew point clean room apparatus according to claim 1, wherein the cooling air is supplied to the cooling coil evenly by the pressurizing means.