JP3273544B2 - Method of introducing air into clean room, method of introducing air into clean room, local equipment, and local equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clean room, a local facility, and a method for introducing air into a clean room, and a method for introducing air into local facilities installed in a clean room. is there.

[0002]

2. Description of the Related Art Conventionally, in a clean room used in factories and laboratories related to semiconductors, foods, pharmaceuticals, and biotechnology, a dry air filter for collecting suspended substances in the air is installed on a ceiling of the clean room. The air that has passed through the dry air filter is introduced into the clean room.

As a method for introducing air into such a clean room, there are a fan filter method as shown in FIG. 6 and an open bay method as shown in FIG. In the fan filter system, a fan filter unit 2 in which a high-performance air filter 21 and a blower 22 are integrated is arranged on a ceiling, and air (fresh air) A that has passed through an outside air conditioner 92 and a filter unit 91 is dried. The fan filter unit 2 is introduced through the coil 8. Then, the clean air that has entered the clean room 1 through the fan filter unit 2 enters the underfloor space from the exhaust port of the free access floor 7 and becomes return air R. It is designed to be introduced into the fan filter unit 2.

In the open bay system, a high-performance air filter 21 is arranged on the ceiling, a blower f ₇ is installed before the dry coil 8, and a position where the downstream of the dry coil 8 and the return air R join the fresh air A is determined. Is provided with a silencer 94.

[0005] In any of the above-mentioned systems, in a conventional clean room, a glass-based air filter whose filter medium is made of glass fiber is used as the high-performance air filter.
Such high-performance air filters include, for example, UL
PA (U ltra L ow P enetration A
ir) filter or, HEPA (H igh E ffic
there is iency P article A ir) filter.

In recent years, with the increase in the degree of integration of semiconductors, the diffusion of not only dust but also gaseous organic substances and inorganic substances into the air in a clean room has become a problem. From glass components other than SiO ₂ contained in the glass fibers of the filter medium (Na, K,
Since Ca, B, P, etc. are generated, non-glass filters using a fluororesin-based or quartz-based fiber as a filter medium instead of glass fiber have been developed so that inorganic substances are not generated from the air filter.

On the other hand, when it is desired to locally increase the cleanness of the clean room, local equipment having the high-performance air filter is installed in the clean room. Such local facilities include so-called clean booths,
Examples include a clean booth in which production equipment such as a semiconductor manufacturing device is incorporated. The conventional local equipment is provided with the glass air filter as the high-performance air filter, and clean air that has passed through the glass air filter in the clean room is introduced into the local equipment.

[0008]

However, compared to glass filters, the non-glass filters have a small dust removal capacity and need to be replaced frequently, and are expensive. There is a problem that it is not economical to install it on the entire ceiling in order to suppress the generation of air.

[0009] In particular, local facilities in which a semiconductor manufacturing apparatus is incorporated are required to prevent inorganic substances from being introduced therein. The present invention has been made in order to solve the problems of the related art, and an economical method capable of preventing inorganic substances from being present in a predetermined portion in a clean room, and the method can be implemented. It is an object of the present invention to provide an air introduction method and a local facility that can prevent an inorganic substance from being present in a clean room and local facilities installed in the clean room.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a dry air filter for collecting suspended substances in the air is installed on a ceiling of a clean room, and the dry air filter is mounted on the ceiling. In the method for introducing air into a clean room, in which the passed air is introduced into a clean room, the dry air filter includes a non-glass air filter in which a filter medium is made of non-glass fiber and a glass air filter in which the filter medium is made of glass fiber. The air is passed through the non-glass air filter to a predetermined portion in the clean room, and the air introduction path into the clean room is changed to the non-glass air filter side area and the glass air. Divide into the filter side area and the air in the glass air filter side area. To provide an air introducing methods to the clean room, characterized in that it has prevented from entering the non-glass-based air filter side area.

Thus, the inside of the clean room is divided into a portion where the air mainly passing through the non-glass type air filter is introduced (the predetermined portion) and a portion where the air mainly passing through the glass type air filter is introduced. Since the air from the glass-based air filter side area does not pass through the non-glass-based air filter, the amount of inorganic substances generated in the predetermined portion is reduced. In addition, since the non-glass filter is partially installed instead of the entire ceiling, the number of filters that need to be replaced frequently is reduced as compared to the case where the non-glass filter is installed over the entire ceiling. .

The non-glass type air filter includes:
The fiber of the filter medium may be of a quartz type or an organic type (polyester type, polyvinyl alcohol type, fluororesin type, etc.), but a fiber using a fluororesin type or quartz type fiber as the filter medium is preferred.

According to a second aspect of the present invention, in the method of the first aspect, the clean room is a clean room for manufacturing semiconductors, and the predetermined portion is a place where the silicon wafer is exposed to air. is there.

The invention according to claim 3 is the invention according to claim 1 or 2
In the method, the set larger than the air velocity V ₂ of the air introduced into the non-glass-based through the air filter wind speed V ₁ of the air introduced into the clean room through the glass-based air filter in a clean room It is characterized by the following.

Thus, the boundary between different air filters
Even if the inside of the clean room is not
The air that has passed through the lath air filter is
It can be difficult to go below the filter. Sand
Usually, the exhaust speed from the clean room to each area
Is set to be the same, in which case the wind speed V ₁
The wind speed V_TwoBy setting a larger value,
Pressure below the non-glass air filter
Pressure in the lower part of the air filter
Air that has passed through a non-glass air filter
It may go down the air filter, but vice versa
Does not occur.

The difference between the wind speeds V ₁ and V ₂ (V ₁ -V ₂ ) is preferably 0.05 to 0.25 m / s. When the wind speed difference (V ₁ −V ₂ ) is less than 0.05 m / s, air passing through the glass-based air filter is more likely to be directed below the non-glass-based air filter as compared with the case where the difference is more than 0.05 m / s. Thus, the effect of reducing the amount of inorganic substances generated in the predetermined portion is reduced. The difference in wind speed (V ₁ −V ₂ ) is 0.2
Even if the speed exceeds 5 m / s, the effect is about the same as the case of 0.25 m / s, so that the power required to cause the difference in wind speed is wasted.

According to a fourth aspect of the present invention, in the method according to any one of the first to third aspects, air is sent from outside the clean room to the non-glass air filter side area, and extra air is discharged from the glass air filter side area to the outside of the clean room. Is discharged. This makes it possible to prevent air in the glass-based air filter side area from entering the non-glass-based air filter side area.

According to a fifth aspect of the present invention, there is provided a clean room in which a dry air filter for collecting suspended substances in the air is installed on a ceiling, wherein a non-glass air filter made of a non-glass fiber is used as a filter medium at a predetermined position on the ceiling. Placed in
At the other positions, a glass-based air filter whose filter medium is made of glass fiber is arranged, and the air introduction path into the clean room is divided into a non-glass-based air filter side area and a glass-based air filter side area, Provided is a clean room characterized in that air in a glass-based air filter side area does not enter a non-glass-based air filter side area.

According to a sixth aspect of the present invention, in the clean room according to the fifth aspect, an air introduction device for feeding air from outside the clean room is connected to the non-glass air filter side area, and the glass air filter side is connected to the non-glass air filter side area. An exhaust device for discharging extra air in the clean room to the outside is connected to the area.

The invention according to claim 7 is the method according to claim 1, wherein the predetermined portion is a place where local equipment is installed, and the dry filter of the local equipment is a non-glass air filter. Features. The present invention
And local facilities are clean booths or clean booths.
The production equipment is built into the base.

According to an eighth aspect of the present invention, the pressure P ₁ of the air introduced into the local equipment through the non-glass air filter of the local equipment is transferred to the clean room in which the local equipment is installed. to provide an air introducing methods to the local features, characterized in that set higher than the pressure P ₂ of the air introduced through the system air filter.

This prevents the air introduced into the clean room through the glass air filter from entering the local equipment without passing through the non-glass air filter.

The difference between the pressures P ₁ and P ₂ (P ₁ −P ₂ ) is preferably 0.5 to 2.0 mmH ₂ O. When the pressure difference (P ₁ −P ₂ ) is less than 0.5 mmH ₂ O, air passing through the glass-based air filter is more likely to enter the local equipment than in the case where the pressure difference is more than 0.5 mmH ₂ O. The possibility that inorganic substances are introduced into the equipment increases. Also, the pressure differential (P ₁ -P ₂₎ exceeds the 2.0mmH ₂ O, the effect of air passing through the glass-based air filter can be prevented from entering the local equipment in the case of 2.0mmH ₂ O Is not preferable because the power required for generating the pressure difference is wasted and the control of the differential pressure becomes difficult.

According to a ninth aspect of the present invention, a local facility having a non-glass air filter is installed in a clean room having a glass air filter, and a fresh air from outside the clean room is installed in an air inlet of the local facility. An air introduction device for feeding air is connected, and excess air in the local facility is discharged into at least one of a glass-based air filter side area of the clean room and outside the clean room. Air introduction method.

According to a tenth aspect of the present invention, as the dry filter , the fibers of the filter medium are made of quartz, polyester, or polyvinyl.
A local facility is provided with an air filter of a nyl alcohol type or a fluororesin type .

[0026]

(First Embodiment) FIG. 1 is a schematic sectional view showing a structure of a clean room corresponding to a first embodiment of the present invention, and FIG. 2 is an air filter on a ceiling surface of the clean room. It is a top view which shows the arrangement state of.

The system for introducing air into the clean room 1 is a fan filter system, and the air filter 21A,
A large number of fan filter units 2A, 2B in which the fan 21B and the blowers 22A, 22B are integrated are installed on the ceiling surface. The black portions indicate that the fan filter unit 2A having the non-glass air filter 21A is disposed, and the other portions indicate that the fan filter unit 2B having the glass air filter 21B is disposed. Show. That is, the non-glass air filter 21A is arranged on the right side (2/5 area) 3R in FIG. 2 of the ceiling surface, and the glass air filter 21B is arranged on the left side (3/5 area) 3L in FIG. .

A ceiling partition plate 4 and an underfloor partition plate 5 are installed at the boundary between the right portion 3R and the left portion 3L below the ceiling and under the floor of the clean room 1, and both introduce air into the clean room 1. The path is divided into a non-glass air filter side area 6A and a glass air filter side area 6B. In addition, the free access floor 7, which is the floor of the clean room 1, has about 10m
A rectangular hole of mx 40 mm is formed in a grid pattern on the entire surface, and the air in the clean room is discharged to each area through this hole. Dry coils 8A and 8B are installed at a height near the ceiling surface of each area.

The HEPA filter F _{1 is connected} to the air inlet below the non-glass air filter side area 6A.
And ULPA connected filter units 91 having a filter F ₂ is, prefilter F _3, medium performance filters F _4, and air blower f ₅ outer conditioner 92 which includes a is connected to the upstream. Further, an exhaust port 93 is placed below the glass-based air filter side area 6B, excess air is adapted to be exhausted by the exhaust fan f ₆ here. Incidentally, the filter unit 91 and the outer conditioner 92 corresponds to the air introduction device of the present invention, an exhaust fan f ₆ correspond to the exhaust system.

[0030] Thus, fresh air A ₁ which has passed through the outdoor air motor 92 and the filter unit 91 is introduced below the non-glass-based air filter side area 6A of the air introduction path, a return exhausted under the floor of the area together with the air R ₁ rises the area dry coil 8A
, And enters the clean room 1 through the non-glass air filter 21A. On the other hand, the glass-based air filter side area 6B, the return air R ₂ exhausted under the floor of the area increases, enters the ceiling of the area side through the dry coil 8B, through the glass-based air filter 21B It is introduced into the clean room 1.

Here, by adjusting the rotation speed of the fan of each fan filter unit, the speed V ₁ of the air blown out of the non-glass air filter 21A is made larger than the speed V _{2 of the} air blown out of the glass air filter 21B. For example, from the clean room 1 to each area 6
A and 6B have the same pumping speed, so the lower part 1A of the non-glass air filter 21A of the clean room 1
Is lower than the lower part 1 of the glass air filter 21B.
It becomes larger than the pressure of B. Therefore, even though the air that has passed through the non-glass air filter 21A may go below the glass air filter 21B (arrow W), the reverse does not occur.

That is, the glass air filter 21B
This makes it difficult for air from flowing to the lower side of the non-glass air filter 21A. Thus, the non-glass air filter 21A is located below the non-glass air filter 21A.
Clean room 1 because only air passed through is introduced
The lower part of the non-glass-based air filter 21A has a smaller amount of generated inorganic substances.

The fresh air A ₁ introduced below the non-glass air filter side area 6A of the air introduction path passes through the non-glass air filter 21A to the lower portion 1A, and the lower portion 1A While circulating with the area 6A of the air introduction path, the air also goes below the glass air filter 21B (arrow W). Lower part 1B of glass air filter 21B in clean room 1
The air that has passed through the glass-based air filter 21B and the air (arrow W) from the lower portion 1A of the non-glass-based air filter 21A are introduced to the lower portion 1B and the area 6B of the air introduction path. circulates the door, excess air is exhausted from the exhaust port 93 by the exhaust fan f _6.

As described above, in this embodiment, the air introduction path into the clean room 1 is divided into the non-glass air filter side area 6A and the glass air filter side area 6A.
B, and the wind velocity V ₁ of the air introduced into the clean room 1 through the non-glass air filter 21A and the wind velocity V _{2 of the} air introduced into the clean room 1 through the glass air filter 21B. By setting a larger value, the air in both areas is prevented from being mixed, so that the inorganic air can hardly be contained in the air directed to the non-glass air filter 21A. This makes it possible to make the air below the non-glass air filter 21A hardly contain inorganic substances.

In this embodiment, as described above,
Wind speed V ₁ of the non-glass-based air filter 21A side by setting larger than the wind speed V ₂ of the glass-based air filter 21B side, even if it is not divided internally clean room 1 is at the interface with different air filters, glass-based air Although the air that has passed through the filter 21B can be made less likely to go below the non-glass air filter 21A, the present invention is not limited to this embodiment, and the boundary position between the non-glass air filter 21A and the glass air filter 21B is not limited. By partitioning the inside of the clean room 1 by the above, there is also included one that makes it difficult for air that has passed through the glass-based air filter 21B to go below the non-glass-based air filter 21A. However, in that case, the space that can be used becomes narrower due to the installation of the partition, or the installation of the partition takes time, so that the partition is not installed by setting the wind speeds V ₁ and V ₂ as in this embodiment. This is preferred for cost and space savings.

In the above-described embodiment, the air introduction system is a fan filter system. However, in the above-described open bay system, a ceiling partition plate and an underfloor partition plate are installed at the boundary between two types of filters, as described above. by doing,
The method of the present invention is implemented by dividing the air introduction path into the clean room into a non-glass air filter side area and a glass air filter side area, and installing a blower for each area.

Further, in the embodiment, the fresh air A ₁ is introduced under the non-glass-based air filter side area 6A of the air introduction path, fresh air A ₁
Is not particularly limited, and may be an intermediate position in the height direction or a ceiling. (First Example) Next, the first embodiment will be described in detail with reference to specific examples.

As the non-glass air filter 21A, P
Commercially available fluororesin air filter using TFE (polytetrafluoroethylene) fiber as a filter material (Kondo Kogyo Co., Ltd.)
And no commercial name), and a commercially available ULPA filter (absolute filter manufactured by Kondo Kogyo Co., Ltd.) as the glass-based air filter 21B, and the following table in the right part 3R and the left part 3L of FIG. The fan filter units 2A and 2B were installed on the ceiling of the clean room 1 in FIG. 1 so that the air filters 21 and 21B were arranged in the combination shown in FIG.

For Nos. 1-4, clean room 1
A non-glass air filter on the right side 3R of the ceiling,
Place a glass-based air filter on the left 3L.
In No. 5, a glass air filter is arranged on the entire ceiling, and in No. 6, a non-glass air filter is arranged on the entire ceiling.

The size of the ceiling surface of the clean room 1 is 6
000 mm x 4800 mm, and as shown in FIG.
A total of 40 air filters each having a size of 600 mm × 1200 mm (16 right side portions 3R and 24 left side portions 3L) were arranged. The speed of the air by adjusting the rotational speed of the blower of each fan filter unit and is blown from an air filter positioned in the speed V ₁ and the left side portion of the air blown out from an air filter positioned in said right portion V ₂ was set as shown in Table 1 below.

As the wall material of the clean room 1,
A partition made of an inorganic material was dry-sealed, and a stainless steel plate was used as a surface material of the floor material.
After operating such a clean room 1, after 7 days, air below the right side portion 3R (at a height of 100 cm from the free access floor 7) is collected, and inorganic and organic substances contained in the air are collected by the following method. analyzed.

For the analysis of inorganic substances, ultrapure water
The air in the clean room was introduced at a flow rate of 10 l / min at the above-mentioned position into the impinger containing 6 ml for 6 hours, and the water in the impinger was subjected to an inductively coupled plasma / mass spectrometry (IPC / MS) apparatus to obtain water. The dissolved inorganic matter was analyzed. The equipment used was Yokogawa-Hewlett
HP-4500 from Packard.

Regarding the analysis of organic matter, 20 l of air in the clean room was collected in the Tenax tube at the above-mentioned position,
This Tenax tube is connected to TCT (Thermal Deso)
rption Cold Trap Injecto
r) The apparatus was mounted and heated while flowing a helium gas to volatilize contained organic substances, and the volatile components were collected and concentrated in a trap tube cooled with liquid nitrogen. This concentrated component was introduced into a gas chromatograph / mass spectrometer (GC / MS) to obtain a total ion chromatogram. The equipment used was Yokogawa-Hewlle
HP-5972A + 7694 from TT Packard
It is.

The mass spectrum of each peak was measured, and the contained organic substances were qualitatively analyzed. Quantitative analysis was performed by GC / MS using a known amount of dodecane as a standard substance.
A chromatogram was obtained by introduction into the apparatus, and the result was expressed in terms of dodecane based on the peak area. This allows analysis up to the order of 10 ng / m ³ .

The results of these analyzes are also shown in Table 1 below.

[0046]

[Table 1]

For the clean rooms No. 2 and No. 6, an air filter (N
o. 2 was used for the ULPA filter, and No. 6 was used for the PTFE filter. Specifically, the time from the time required for the pressure loss of the filter to increase by 5 mmAq or more to the time when the maximum allowable pressure loss is reached is estimated, and this is taken as the usable time. However, the PTFE filter of No. 6 was 2.8 years old.

As can be seen from the results in Table 1, No. 1 to No. 4 in which the arrangement of the filters was the same and the difference between the wind speeds V ₁ and V ₂ was changed.
Nos. 1 to 3 having a wind speed difference (V ₁ −V ₂ ) of 0.05 m / s or more are practically usable in terms of the concentration of inorganic substances, and the wind speed difference (V ₁ −V ₂₎ ) Is “0” No.
No. 4 was not practically usable. In particular, for Nos. 1 and 2, although Na, K, and Ca were slightly detected in the inorganic substance concentration, B, which is a particular problem in semiconductors, was below the detection limit and the organic substance concentration was low. Is a place where the silicon wafer comes into direct contact with air, which is particularly suitable as a clean room for semiconductor manufacturing.

A glass air filter was installed on the entire surface.
No. 5 has high concentrations of both organic and inorganic substances,
Inorganic substances comparable to those in conventional clean rooms for semiconductor manufacturing have been analyzed. That is, since the concentration of B or an organic substance, which is particularly problematic in semiconductors, is high, it is not suitable for a clean room strongly demanded by the semiconductor industry at present. The above analysis of the air below the left portion of the clean room of No. 2 was almost the same as the result below the right portion of No. 5.

No. 6 in which a non-glass type air filter (PTFE type) was installed on the entire surface was excellent in that both the concentration of organic matter and the concentration of inorganic matter were low, and the amount of inorganic matter and organic matter generated in the clean room was small. However, PTFE filters have to be replaced frequently due to short usable time and are not economical due to high price. On the other hand, in Nos. 1 to 3 corresponding to the embodiment of the present invention, by partially disposing the PTFE filter, the effect of reducing the concentration of the organic substance and the concentration of the inorganic substance can be obtained at low cost. In addition, when the same analysis was performed for each clean room after one year of operation time, B (boron) was below the detection limit in Nos. 1 to 3, and the organic matter concentration was almost the same as the value after 7 days shown in Table 1. Did not.

As a non-glass type air filter, P
Using a quartz air filter using quartz fiber as the filter medium instead of the TFE filter as the filter on the right side, operating the clean room under the same conditions as Nos. 1 to 3, and measuring the inorganic substance concentration and the organic substance concentration. Regarding the concentration, the performance was equal to or higher than that of Nos. 1 to 3. 20-40 μg / m ³ for organic matter concentration
Met. Further, since the quartz air filter is expensive, the cost can be reduced by partially using the air filter as in the method of the present invention. (Second Embodiment) FIG. 3 is a schematic sectional view showing the structure of a clean room corresponding to a second embodiment of the present invention.

In this embodiment, a local facility 10 incorporating a semiconductor manufacturing apparatus is installed on a free access floor 7 in a non-glass air filter side area 1A in the same clean room as in FIG. This local equipment 10
Is a fan filter unit 2A in which a non-glass air filter 21A and a blower 22A are integrated on the ceiling.
Is attached, glass-based air filter side area 1
An opening 11 for exhaust is provided in the wall material on the B side.

Thus, air that has passed through the non-glass air filter 21A on the ceiling of the clean room and the non-glass air filter 21A on the ceiling of the local equipment 10 is introduced into the local equipment 10. And this local equipment 1
The pressure P ₁ of the air in the 0 is set to be larger than the air P ₂ of the glass-based air filter side area 1B. Therefore, the pressure P ₁ of the air in the local facility 10 is discharged from the opening 11 to the glass-based air filter side area 1B, but the air in the area 1B is not introduced into the local facility 10.

Therefore, only the air that has twice passed through the non-glass air filter is introduced into the local facility 10, so that the amount of inorganic substances generated in the local facility 10 is reduced. (Second Example) In the second embodiment, the clean room to be used has the No. 1 configuration of the first example, and the local equipment 10 has a size of 1800 mm wide × 180 depth.
The filter material of the air filter 21A of the fan filter unit 2A mounted on the ceiling was set to 600 mm × 600 mm. In addition, local equipment 1
The air in the area on the non-glass air filter side is sent into the area 0 by the blower 22A at a rate of 4 m ³ / min.
The pressure P ₁ of the air inside the chamber is 1.5 mmH ₂ O higher than the atmospheric pressure, and the pressure P
₂ was set to be higher than the atmospheric pressure by 0.5 mmH ₂ O.

Then, the clean room 1 and the local equipment 10
Was operated, and the air in the local facility 10 was analyzed in the same manner as in the first embodiment. As a result, the same result as that of No. 1 in the first embodiment was obtained with respect to the inorganic substance concentration. ) Was below the detection limit. (Third Embodiment) FIG. 4 is a schematic sectional view showing a structure of a clean room corresponding to a third embodiment of the present invention.

In this embodiment, the open bay system is the same as that shown in FIG.
A local facility 10 in which a semiconductor manufacturing apparatus is incorporated is installed in a clean room in which only a semiconductor device is installed. Therefore, the entire inside of the clean room is a glass-based air filter side area 1B.

In the local facility 10, a fan filter unit 2A in which a non-glass air filter 21A and a blower 22A are integrated is mounted on the ceiling. Further, the air inlet of the local facility 10 and the external filter unit 91 are connected by a pipe 95 so that the fresh air A is directly introduced into the local facility 10.

The pressure P of the air in the local facility 10
_1, because it is set to be greater than the pressure P ₂ in the air in the clean room 1B, excess air of the local equipment 10 is discharged naturally from the gap between the local equipment 10 in a clean room 1B, The air in the clean room 1B is not introduced into the local facility 10.

Therefore, even if only the air that has passed through the glass-based air filter 21B is introduced into the clean room, the air introduced into the local facility 10 is such that fresh air A has passed through the non-glass-based air filter. Therefore, the amount of inorganic substances generated in the local facility 10 is reduced. That is, in this embodiment, the air filters in the clean room 1B are all relatively inexpensive glass-based air filters 21B, but by introducing only the fresh air A, the inorganic substance concentration in the local equipment 10 can be reduced over a long period of time. Therefore, the cost of the air filter is economical. (Third Embodiment) In the third embodiment, the clean room to be used is configured as No. 5 of the first embodiment, and the same local equipment 10 as the second embodiment is installed. Inside, fresh air A was sent at 4 m ³ / min by a blower 22A, and the pressure P ₁ of air in the local facility 10 was made higher by 0.5 mmH ₂ O than the pressure P ₂ of air in the clean room 1B.

Then, the clean room 1B and the local equipment 1
0, and the air in the local facility 10 was analyzed in the same manner as in the first embodiment. As a result, the same result as that of No. 1 in the first embodiment was obtained with respect to the inorganic substance concentration. The concentration of B) was below the detection limit. As described above, even if the local equipment 10 is installed in the clean room 1B in which only the glass-based air filter 21B is installed, the fresh air A is directly introduced into the local equipment 10 so that the air in the local equipment 10 is air-cooled. Inorganic substances can be prevented from being present therein. (Fourth Embodiment) FIG. 5 is a schematic sectional view showing the structure of a clean room corresponding to a fourth embodiment of the present invention.

In this embodiment, the fan filter system is the same as that shown in FIG.
A local facility 10 incorporating a semiconductor manufacturing apparatus is installed in a clean room in which only 1B is installed. Therefore, the entire inside of the clean room is a glass-based air filter side area 1B.

The local equipment 10 has a fan filter unit 2A in which a non-glass air filter 21A and a blower 22A are integrated on the ceiling, and the local equipment 10 has a glass air filter of the clean room 1B. The air that has passed through 21B is introduced after passing through the non-glass air filter 21A of the local facility 10. The air in the clean room 1B enters the underfloor space from the exhaust port of the free access floor 7 to become return air R, is mixed with fresh air A, passes through a glass air filter, and is circulated into the clean room 1B. ing.

The pressure P of the air in the local facility 10
_1, because it is set to be greater than the pressure P ₂ in the air in the clean room 1B, excess air of the local equipment 10 is discharged naturally from the gap between the local equipment 10 in a clean room 1B, The air in the clean room 1B is not introduced into the local facility 10.

Therefore, since only the air that has passed through the non-glass air filter 21A is introduced into the local facility 10, the amount of inorganic substances generated in the local facility 10 is reduced. (Fourth embodiment) In the fourth embodiment, the clean room to be used is configured as No. 5 of the first embodiment, and the same local equipment 10 as the second embodiment is installed. Inside, fresh air A was sent at 4 m ³ / min by a blower 22A, and the pressure P ₁ of air in the local facility 10 was made higher by 0.5 mmH ₂ O than the pressure P ₂ of air in the clean room 1B.

Then, the clean room 1B and the local equipment 1
0 was operated and the air in the local facility 10 was analyzed in the same manner as in the first embodiment. In the measurement after the operation time of 7 days and 1 year, the inorganic substance concentration was measured in the first embodiment.
No. 1 was obtained, and in particular, the concentration of boron (B) was below the detection limit. However, the operating time is one year 2
Months later, the boron (B) concentration was 35 ng / m ^3.
And the detected concentration increased as the operating time increased. When local equipment provided with a glass air filter is installed in this clean room, the concentration of boron (B) present in the air in the local equipment is 120 ng.
/ M ³ .

As described above, the glass air filter 21
When the local equipment 10 is installed in the clean room 1B to which only B is attached, and the circulating air in the clean room is introduced into the local equipment 10, as the number of times of passing through the glass air filter increases. In addition, the concentration of inorganic substances contained in the circulating air increases. Then, as the operating time increases, when the circulating air having a high inorganic substance concentration passes through the non-glass air filter 21A of the local facility 10, the inorganic substances in the circulating air tend to be accumulated in the non-glass air filter 21A. Therefore, an inorganic substance comes to exist in the air in the local facility 10.

However, according to the fourth embodiment, when the operation time is short, the inorganic substance can be prevented from being present in the local facility 10, and therefore there is no particular problem in the case of short-term use. This is suitable because there is no need to install new piping in an existing clean room as in the third embodiment.

[0068]

As described above, according to the method of the first aspect, the inside of the clean room can be made an area in which the inorganic substance concentration is partially reduced, and an expensive non-glass air filter is provided on the entire ceiling. The cost can be suppressed lower than in the case of installation.

According to the method of the second aspect, the air contacting the silicon wafer can be reduced in inorganic content, so that the yield of semiconductor manufacturing can be improved.

According to the method of the third aspect, even if the inside of the clean room is not partitioned at the boundary position between different air filters, it is difficult for air passing through the glass air filter to go below the non-glass air filter. In addition, the concentration of inorganic substances below the non-glass air filter can be easily reduced.

According to the method of claim 4, since the air in the glass-based air filter side area can be prevented from entering the non-glass-based air filter side area, the inorganic concentration below the non-glass-based air filter can be reduced. It can be easily reduced.

According to the clean rooms of the fifth and sixth aspects, the methods of the first to fourth aspects can be performed. According to the method of claim 7, since the air that has passed through the non-glass air filter twice is introduced into the local equipment, the concentration of inorganic substances in the air in the local equipment can be reduced.

According to the method of the eighth aspect, the air in the glass-based air filter-side area of the clean room is prevented from directly entering the local facility without passing through the non-glass-based air filter. Since only the air that has passed through the non-glass air filter is introduced, the concentration of inorganic substances in the air in the local facility can be easily reduced.

According to the method of the ninth aspect, even if air that has passed through the glass air filter is introduced into the clean room, the air introduced into the local equipment is such that fresh air passes through the non-glass air filter. Since only the fuel has passed, the amount of inorganic substances generated in the local equipment is reduced. That is, according to this method, even if a part or all of the air filter attached to the clean room is a relatively inexpensive glass-based air filter, the concentration of inorganic substances in local equipment can be reduced over a long period of time, so that it is economical. is there.

According to the local facility of the tenth aspect, the concentration of inorganic substances in the air in the local facility can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a structure of a clean room corresponding to a first embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement state of an air filter on a ceiling surface of the clean room in FIG. 1;

FIG. 3 is a schematic cross-sectional view illustrating a structure of a clean room corresponding to a second embodiment of the present invention.

FIG. 4 is a schematic sectional view showing a structure of a clean room corresponding to a third embodiment of the present invention.

FIG. 5 is a schematic sectional view showing a structure of a clean room corresponding to a fourth embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a structure (fan filter system) of a conventional clean room.

FIG. 7 is a schematic sectional view showing a structure (open bay system) of a conventional clean room.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Clean room 2, 2A, 2B fan filter unit 10 Local equipment 21 Air filter 21A Non-glass air filter 21B Glass air filter 6A Non-glass air filter side area of air introduction path 6B Glass air filter side area of air introduction path 91 filter unit (air introduction device) 92 outer conditioner (air introduction device) f ₆ exhaust fan (exhaust device)

Continued on the front page (51) Int.Cl. ⁷ Identification code FI F24F 3/044 F24F 3/044 7/06 7/06 C H01L 21/02 H01L 21/02 D // E04H 5/02 E04H 5/02 B (56) References JP-A-6-302487 (JP, A) JP-A-2-61414 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 46/00 B01D 46 / 52 B01L 1/04 F24F 3/044 F24F 7/06 H01L 21/02

Claims (10)

(57) [Claims] 1. A method for introducing air into a clean room, wherein a dry air filter for collecting suspended substances in the air is installed on a ceiling of a clean room, and air passing through the dry air filter is introduced into the clean room. As an air filter, a non-glass air filter in which the filter medium is made of non-glass fiber and a glass air filter in which the filter medium is made of glass fiber are respectively arranged at predetermined positions on the ceiling, and air that has passed through the non-glass air filter is removed. While introducing air into the clean room, the air introduction path into the clean room is divided into a non-glass air filter side area and a glass air filter side area. Specially to prevent the air filter from entering the air filter side area. Air method of introducing into the clean room to be. 2. The method for introducing air into a clean room according to claim 1, wherein said clean room is a clean room for manufacturing semiconductors, and said predetermined portion is a place where a silicon wafer is exposed to air. 3. The method according to claim 1, wherein the wind speed of the air introduced into the clean room through the non-glass air filter is set to be higher than the wind speed of the air introduced into the clean room through the glass air filter. The method for introducing air into a clean room according to claim 1 or 2, wherein: 4. The method according to claim 1, wherein air is sent into the non-glass air filter side area from outside the clean room, and excess air is discharged from the glass air filter side area outside the clean room. The method for introducing air into a clean room according to any one of the above. 5. A clean room in which a dry air filter for collecting suspended matter in the air is installed on a ceiling, wherein a non-glass air filter made of a non-glass fiber is placed at a predetermined position on the ceiling. At the position of, a glass-based air filter whose filter medium is made of glass fiber is placed, and the air introduction path into the clean room is divided into a non-glass-based air filter side area and a glass-based air filter side area, A clean room characterized in that the air in the air filter side area does not enter the non-glass air filter side area. 6. An air introduction device for feeding air from outside the clean room to the non-glass air filter side area, and discharging extra air in the clean room to the glass air filter side area. 6. An exhaust device connected to the apparatus, wherein:
The described clean room. 7. The air introduction into a clean room according to claim 1, wherein the predetermined portion is a place where local equipment is installed, and a dry filter of the local equipment is a non-glass air filter. Method. 8. The pressure of air introduced into the local facility through the non-glass air filter of the local facility is introduced into the clean room where the local facility is installed through the glass air filter. A method for introducing air into local equipment, characterized in that the pressure is set higher than the pressure of the air to be blown. 9. An air introduction device for installing local equipment having a non-glass air filter in a clean room having a glass air filter, and for feeding fresh air from outside the clean room to an air inlet of the local equipment. And the extra air in the local equipment
A method of introducing air into local facilities, wherein the air is discharged toward at least one of a glass-based air filter side area of a clean room and the outside of the clean room. 10. The fiber of a filter medium is used as a dry filter.
Quartz-based, polyester-based, polyvinyl alcohol-based,
Or local equipment characterized by having an air filter made of fluororesin .