JPH09101051A - Method for leading air into clean room, clean room, method for leading air into local equipment, and local equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the inside of a clean room from contamination with inorganic matter. SOLUTION: In the ceiling of a clean room 1 a series of non-glass-based air filters 21A are disposed in the right part as shown in diagram and a series of glass-based air filters 21B, in the left part. By means of a ceiling chamber- partitioning board 4 and an under-the-floor-partitioning board 5 the course by which air is led into the clean room 1 is divided into a non-glass-based air filter side area 6A and a glass-based air filter side area 6B. The velocity V1 at which the air is blown out from the non-glass-based air filters 21A is made greater than the velocity V2 at which the air is blown out from the glass- based air filters 21B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

As a method of 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 method, the fan filter unit 2 in which the high-performance air filter 21 and the blower 22 are integrated is arranged on the ceiling, and the air (fresh air) A passing through the external air conditioner 92 and the filter unit 91 is dry. It is adapted to be introduced into the fan filter unit 2 via 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 to become the return air R, and together with the fresh air A described above, passes through the dry coil 8 and 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 in front of the dry coil 8, and a position downstream of the dry coil 8 and a position where the return air R joins the fresh air A are set. A silencer 94 is installed at.

In any of the above-mentioned systems, a conventional clean room uses a glass type air filter having a glass fiber as a filter medium as the high performance air filter.
As such a high performance air filter, 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.

Recently, as semiconductors have become highly integrated, air in a clean room has become a problem in which not only dust but also gaseous organic substances and inorganic substances diffuse. From the glass components other than SiO ₂ contained in the glass fiber of the filter medium (Na, K,
Since Ca, B, P, etc.) are generated, non-glass type filters using fluororesin type or quartz type fibers instead of glass fibers as a filter medium have been developed so that inorganic substances are not generated from the air filter.

On the other hand, if it is desired to locally increase the cleanliness of the clean room, local equipment equipped with the high performance air filter is installed in the clean room. As such local equipment, so-called clean booths,
An example is a clean booth in which production equipment such as semiconductor manufacturing equipment is incorporated. Then, the glass-based air filter as the high-performance air filter is attached to the conventional local equipment, and clean air that has passed through the glass-based air filter in the clean room is introduced into the local equipment.

[0008]

However, the non-glass type filter has a smaller dust removing capacity than the glass type filter and must be replaced frequently, and the cost is high, so that the inorganic type clean room is not used. There is a problem that it is not economical to install it on the entire ceiling in order to suppress the occurrence of

Further, in particular, local equipment in which a semiconductor manufacturing apparatus is incorporated is required to prevent introduction of inorganic substances into the inside. The present invention has been made in order to solve the above-mentioned problems of the prior art, and an economical method capable of preventing the presence of an inorganic substance in a predetermined portion in a clean room, and the method can be implemented. It is an object of the present invention to provide a clean room and an air introduction method and a local facility capable of preventing inorganic substances from existing in the local facility installed in the clean room.

[0010]

In order to achieve the above object, the invention according to claim 1 is to install a dry air filter for collecting suspended matter in the air on the ceiling of a clean room, and to install the dry air filter. In the method of introducing air into a clean room to introduce the air that has passed through, as the dry air filter, a non-glass air filter comprising a non-glass fiber filter material and a glass-based air filter comprising a glass fiber filter element The air is passed through the non-glass type air filter to a predetermined part in the clean room, and the air introduction path into the clean room is provided in the non-glass type air filter side area and the glass type air. The air in the glass-based air filter side area is divided into the 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.

As a result, the inside of the clean room is divided into a portion into which air mainly passing through the non-glass air filter (the predetermined portion) and a portion into which air mainly passing through the glass air filter is introduced. Further, 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. Also, because the non-glass filters are installed partially instead of the entire ceiling, the number of filters that must be replaced frequently is smaller than when installing non-glass filters on the entire ceiling. .

As the non-glass type air filter,
Examples of the filter material include fibers of quartz type and organic type (polyester type, polyvinyl alcohol type, fluororesin type, etc.), and it is preferable to use fluororesin type or quartz type fibers for the filter medium.

The invention according to claim 2 is the method according to claim 1, wherein the clean room is a clean room for semiconductor manufacturing, and the predetermined portion is a place where a 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 above method, the wind speed V ₁ of the air introduced into the clean room through the non-glass air filter is set higher than the wind speed V _{2 of the} air introduced into the clean room through the glass air filter. It is characterized by that.

This allows the boundaries of different air filters to be
Even if the inside of the clean room is not
The non-glass type air filter
It is possible to make it difficult to go below the filter. Sand
The exhaust speed from the clean room to each area is usually
Are set to the same, but in that case, the wind speed V ₁
The wind speed V_TwoBy setting a larger value, the clean
The pressure below the non-glass air filter
The pressure becomes higher than the pressure in the lower part of the air filter.
Therefore, the air that has passed through the non-glass type air filter is glass type.
It may go below 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 difference in wind speed (V ₁ −V ₂ ) is less than 0.05 m / s, the air passing through the glass-based air filter is more likely to travel to the lower side of the non-glass-based air filter than when the difference is more than 0.05 m / s. As a result, the effect of reducing the amount of inorganic substances generated in the predetermined portion is reduced. Moreover, the wind speed difference (V ₁ −V ₂ ) is 0.2.
Even if it exceeds 5 m / s, the same effect as in the case of 0.25 m / s is obtained, so that the power required for causing the wind speed difference is wasted.

According to a fourth aspect of the present invention, in the method of the first to third aspects, air is sent from outside the clean room to the non-glass type air filter side area, and excess air is discharged from the glass type air filter side area to the outside of the clean room. It is characterized by being discharged to. Thereby, the air in the glass-based air filter side area can be prevented from entering the non-glass-based air filter side area.

According to a fifth aspect of the present invention, in a clean room in which a dry air filter for collecting suspended matter in the air is installed on a ceiling, a non-glass air filter having a non-glass fiber as a filter medium is provided at a predetermined position on the ceiling. Placed in
In addition to arranging a glass-based air filter in which the filter medium is made of glass fiber at other positions, 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, (EN) Provided is a clean room characterized in that the air in the glass-based air filter side area does not enter the 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 introducing device for sending air from outside the clean room is connected to the non-glass type air filter side area and the glass type air filter side. An exhaust device for discharging excess air in the clean room to the outside is connected to the area.

According to a seventh aspect of the present invention, in the method according to the first aspect, 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. Characterize.

In the invention according to claim 8, the pressure P ₁ of the air which is introduced into the local facility through the non-glass type air filter of the local facility is transferred into the clean room in which the local facility is installed. Provided is a method for introducing air into a local facility, which is characterized by setting the pressure higher than the pressure P _{2 of} air introduced through a system air filter.

Thus, the air introduced into the clean room through the glass-based air filter is prevented from entering the local facility without passing through the non-glass-based air filter.

The difference (P ₁ -P ₂ ) between the pressures P ₁ and 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, compared with the case where it is more than 0.5 mmH ₂ O, the air passing through the glass-based air filter is more likely to enter the local facility, and Inorganic substances are more likely to be introduced into the facility. 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 Since it is about the same as, the power required to generate the pressure difference is wasted and the control of the differential pressure becomes difficult, which is not preferable.

In the invention according to claim 9, the local equipment equipped with the non-glass air filter is installed in a clean room equipped with the glass air filter, and the fresh air from outside the clean room is installed in the air inlet of the local equipment. In addition to connecting an air introduction device that sends in air, excess air in the local facility is discharged into at least one of the glass air filter side area of the clean room and the outside of the clean room into the local facility. The method of introducing air is provided.

The invention according to claim 10 provides a local facility characterized by comprising a non-glass air filter as a dry filter.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a schematic sectional view showing the structure of a clean room corresponding to the first embodiment of the present invention, and FIG. 2 is a plan view showing the arrangement of air filters on the ceiling surface of this clean room. Is.

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

A ceiling partition plate 4 and an underfloor partition plate 5 are installed at the boundary between the right side portion 3R and the left side portion 3L in the space above the ceiling and under the floor of the clean room 1, and both of them introduce air into the clean room 1. The route is divided into a non-glass type air filter side area 6A and a glass type air filter side area 6B. In addition, the free access floor 7 that forms the floor of the clean room 1 is approximately 10 m
Rectangular holes of m × 40 mm are formed on the entire surface in a lattice pattern, and the air in the clean room is discharged to each area through the holes. Further, dry coils 8A and 8B are installed at a height near the ceiling surface of each area.

At the air inlet below the non-glass air filter side area 6A, the HEPA filter F ₁
And a filter unit 91 having a ULPA filter F ₂ are connected, and an upstream air conditioner 92 having a pre-filter F ₃ , a medium performance filter F ₄ , and an air supply fan f ₅ is connected upstream of the filter unit 91. 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. The filter unit 91 and the external conditioner 92 correspond to the air introducing device of the present invention, and the exhaust fan f ₆ corresponds to the exhaust device.

As a result, the fresh air A _{1 that} has passed through the air conditioner 92 and the filter unit 91 is introduced below the non-glass type air filter side area 6A of the air introduction path, and is exhausted under the floor of the area. Dry coil 8A ascends the area together with air R ₁
Through the non-glass type air filter 21A to be introduced into the clean room 1 via the non-glass type air filter 21A. On the other hand, in the glass-based air filter side area 6B, the return air R ₂ exhausted under the floor of the area rises, enters the ceiling under the area via the dry coil 8B, and passes through the glass-based air filter 21B. It is installed in 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 from the non-glass air filter 21A can be made larger than the speed V _{2 of the} air blown from the glass air filter 21B. For example, from clean room 1 to each area 6
Since the exhaust speeds to A and 6B are the same, the lower part 1A of the non-glass air filter 21A of the clean room 1
Is applied to the lower part 1 of the glass-based air filter 21B.
It becomes larger than the pressure of B. Therefore, although the air that has passed through the non-glass type air filter 21A may go to the lower side of the glass type air filter 21B (arrow W), the reverse does not occur.

That is, the glass type air filter 21B
It becomes difficult for the air from the head to go below the non-glass air filter 21A. As a result, the non-glass air filter 21A is provided below the non-glass air filter 21A.
Only the air that has passed through is introduced, so clean room 1
In the lower portion of the non-glass air filter 21A, the amount of generated inorganic substances is small.

Further, the fresh air A ₁ introduced below the non-glass type air filter side area 6A of the air introduction path passes through the non-glass type air filter 21A toward the lower portion 1A thereof and the lower portion 1A. While circulating in the area 6A of the air introduction path, it also goes below the glass-based air filter 21B (arrow W). Lower part 1B of glass type air filter 21B in clean room 1
Is introduced with air that has passed through the glass-based air filter 21B and air (arrow W) from the lower portion 1A of the non-glass-based air filter 21A. This air is introduced into the lower portion 1B and the area 6B of the air introduction path. And the 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 provided with the non-glass type air filter side area 6A and the glass type air filter side area 6
B and the wind speed V ₁ of the air introduced into the clean room 1 through the non-glass air filter 21A and the wind speed V _{2 of the} air introduced into the clean room 1 through the glass air filter 21B. Since the air in both areas is prevented from being mixed by setting it to a larger value, it is possible to make the air toward the non-glass air filter 21A contain almost no inorganic substances. As a result, the air below the non-glass air filter 21A can be made to contain almost no inorganic substances.

In this embodiment, as described above,
By setting the wind speed V ₁ on the non-glass type air filter 21A side higher than the wind speed V ₂ on the glass type air filter 21B side, even if the inside of the clean room 1 is not partitioned at the boundary position of different air filters, the glass type air filter It is possible to make it difficult for the air that has passed through the filter 21B to go below the non-glass air filter 21A, but 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 thereto. By partitioning the inside of the clean room 1 with, it is difficult to direct the air passing through the glass-based air filter 21B to the lower side of 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, and it takes time and effort to install the partition. Therefore, unlike in this embodiment, the wind speeds V ₁ and V ₂ are set and the partition is not installed. It is preferable to save cost and space.

Further, in the above-mentioned embodiment, the air introduction method is the fan filter method, but in the above-mentioned open bay method as well, similarly to the above, the ceiling partition plate and the underfloor partition plate are installed at the boundary position between the two types of filters. 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 in 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
The introduction height of the above into the area 6A is not particularly limited, and may be an intermediate position in the height direction or the ceiling. (First Example) Next, details of the first embodiment will be described with reference to specific examples.

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

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

The size of the ceiling surface of the clean room 1 is 6
000 mm × 4800 mm, 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. In addition, the rotation speed of the blower of each fan filter unit is adjusted so that the speed V _{1 of the} air blown out from the air filter arranged in the right side portion and the speed of the air blown out from the air filter arranged in the left side 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 plate was used as the surface material of the floor material.
Such a clean room 1 is operated, and after 7 days, the air below the right side portion 3R (at a height of 100 cm from the free access floor 7) is collected, and the inorganic and organic substances contained in the air are collected by the following method. analyzed.

For the analysis of inorganic substances, 200% ultrapure water was used.
The air in the clean room was introduced into the impinger containing ml at the above-mentioned position at a flow rate of 10 l / min for 6 hours, and the water in this impinger was applied to an inductively coupled plasma / mass spectrometry (IPC / MS) device to obtain water. Inorganic substances dissolved in were analyzed. The equipment used was Yokogawa-Hewlett
It is HP-4500 type manufactured by Packard.

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

A mass spectrum was measured for each of the peaks, and the contained organic substances were qualitatively analyzed. In addition, quantitative analysis was performed using GC / MS with a known amount of dodecane as a standard substance.
A chromatogram was obtained by introducing it into the device, and displayed in dodecane conversion value 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]

In addition, regarding the No. 2 and No. 6 clean rooms, the air filter (N
The usable time of the ULPA filter for No. 2 and the PTFE filter for No. 6) was examined. Specifically, the time it takes for the pressure loss of the filter to rise by 5 mmAq or more to reach the maximum allowable pressure loss is estimated, and when this is taken as the usable time, the No. 2 ULPA filter takes 5 years. However, the No. 6 PTFE filter was for 2.8 years.

As can be seen from the results in Table 1, Nos. 1 to 4 in which the difference in wind speeds V ₁ and V ₂ was changed under the same filter arrangement.
In No. 1 to No. 1 having a wind speed difference (V ₁ -V ₂ ) of 0.05 m / s or more, practical use is possible in terms of the concentration of the inorganic substance, and the wind speed difference (V ₁ -V ₂ ) Is “0”.
No. 4 was practically unusable. Especially for Nos. 1 and 2, although the concentrations of inorganic substances were slightly detected for Na, K, and Ca, B, which is a particular problem in semiconductors, is below the detection limit, and the concentration of organic substances is also low. By making the location where the silicon wafer directly contacts the air, it becomes particularly suitable as a clean room for semiconductor manufacturing.

A glass-based air filter was installed on the entire surface.
No. 5 has a high concentration of both organic and inorganic substances,
The same level of inorganic substances as in conventional clean rooms for semiconductor manufacturing has been analyzed. That is, since the concentration of B and organic substances, which are particularly problematic in semiconductors, is high, they are not suitable for clean rooms, which are currently strongly demanded by the semiconductor industry. In addition, when the above-mentioned analysis was performed on the air below the left side portion of the clean room of No. 2, it was almost the same as the result below the right side portion of No. 5.

Further, No. 6 in which a non-glass air filter (PTFE type) is installed on the entire surface is excellent in that both the concentration of organic substances and the concentration of inorganic substances are low and the amount of inorganic substances and organic substances generated in the clean room is small. However, since the PTFE filter has a short usable time, it must be replaced frequently, and it is not economical because of its 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 organic substance concentration and the inorganic substance concentration can be obtained at low cost. In addition, when the same analysis was performed for each clean room after 1 year of operation, 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. There wasn't.

As a non-glass type air filter, P
A quartz air filter using quartz fiber as a filter material was used as a filter for the right part instead of the TFE filter, and the clean room was operated under the same conditions as No. 1 to 3, and the inorganic and organic concentrations were measured. Regarding the concentration, the performance was equal to or higher than Nos. 1-3. The organic matter concentration is 20 to 40 μg / m ^3.
Met. Further, since the quartz type air filter is also expensive, it is possible to reduce the cost by partially using it 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 the second embodiment of the present invention.

In this embodiment, a local facility 10 incorporating a semiconductor manufacturing apparatus is installed on the free access floor 7 in the 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 and the area 1 on the glass air filter side
An opening 11 for exhaust is provided in the wall material on the B side.

As a result, the air that has passed through the non-glass air filter 21A on the clean room ceiling 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 equipment 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 equipment 10.

Therefore, since only the air that has passed through the non-glass air filter doubly is introduced into the local facility 10, the amount of inorganic substances generated in the local facility 10 is reduced. (Second Example) In the second embodiment, the clean room used is the No. 1 configuration of the first example, and the local facility 10 has a size of width 1800 mm x depth 180.
The filter material of the air filter 21A of the fan filter unit 2A mounted on the ceiling was set to 0 mm x height 2700 mm and set to 600 mm x 600 mm. Local equipment 1
The air in the non-glass type air filter side area was blown into the 0 at 4 m ³ / min by the blower 22A, and the local equipment 10
The pressure P ₁ of the inside air is higher than the atmospheric pressure by 1.5 mmH ₂ O, and the pressure P of the air in the glass-based air filter side area is P 1.
₂ was set to be 0.5 mmH ₂ O higher than atmospheric pressure.

The clean room 1 and the local equipment 10
When the air in the local facility 10 was analyzed in the same manner as in the first embodiment, the same results as those of No. 1 of the first embodiment were obtained with respect to the concentration of inorganic substances, and in particular, boron (B ) Was below the detection limit. (Third Embodiment) FIG. 4 is a schematic sectional view showing the structure of a clean room corresponding to the third embodiment of the present invention.

In this embodiment, the same open bay system as in FIG. 7 is used, and the glass-based air filter 21B is installed on the ceiling.
A local facility 10 in which a semiconductor manufacturing apparatus is incorporated is installed in a clean room in which only a chisel is attached. Therefore, the entire interior of this clean room is the glass-based air filter side area 1B.

In this local equipment 10, a fan filter unit 2A in which a non-glass air filter 21A and a blower 22A are integrated is attached to the ceiling. In addition, the air inlet of the local equipment 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 equipment 10.

Further, the pressure P of the air in the local equipment 10
_{Since 1} is set to be higher than the pressure P ₂ of the air in the clean room 1B, the excess air in the local equipment 10 is naturally discharged to the clean room 1B from the gap of the local equipment 10, 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 equipment 10 is the fresh air A that 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 of the clean room 1B are all glass air filters 21B which are relatively inexpensive, but the introduction of only the fresh air A can reduce the concentration of inorganic substances in the local facility 10 for a long period of time. Therefore, the cost of the air filter is economical. (Third Example) In the third embodiment, the clean room to be used has the configuration of No. 5 of the first example, and the same local facility 10 as that of the second example is installed. Fresh air A was blown into the inside by a blower 22A at a rate of 4 m ³ / min so that the pressure P ₁ of air in the local equipment 10 was higher than the pressure P ₂ of air in the clean room 1B by 0.5 mmH ₂ O.

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, the same results as those of No. 1 of the first embodiment were obtained with respect to the concentration of inorganic substances, and in particular, boron ( The concentration of B) was below the detection limit. Thus, even if the local equipment 10 is installed in the clean room 1B in which only the glass-based air filter 21B is installed, by introducing the fresh air A directly into the local equipment 10, the air in the local equipment 10 is It is possible to prevent the presence of inorganic substances therein. (Fourth Embodiment) FIG. 5 is a schematic sectional view showing the structure of a clean room corresponding to the fourth embodiment of the present invention.

In this embodiment, the same fan filter system as in FIG. 6 is used, and the glass-based air filter 2 is installed on the ceiling.
A local facility 10 in which a semiconductor manufacturing apparatus is incorporated is installed in a clean room in which only 1B is installed. Therefore, the entire interior of this clean room is the glass-based air filter side area 1B.

The local equipment 10 is provided with a fan filter unit 2A in which a non-glass air filter 21A and a blower 22A are integrated on the ceiling. Inside the local equipment 10, the glass air filter of the clean room 1B is installed. The air passing 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, becomes return air R, is mixed with the fresh air A, passes through the glass-based air filter, and is circulated and introduced into the clean room 1B. ing.

Further, the pressure P of the air in the local equipment 10
_{Since 1} is set to be higher than the pressure P ₂ of the air in the clean room 1B, the excess air in the local equipment 10 is naturally discharged to the clean room 1B from the gap of the local equipment 10, 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 type air filter 21A is introduced into the local facility 10, the amount of inorganic substances generated in the local facility 10 is reduced. (Fourth Example) In the fourth embodiment, the clean room to be used has the configuration of No. 5 of the first example, and the same local facility 10 as that of the second example is installed. Fresh air A was blown into the inside by a blower 22A at a rate of 4 m ³ / min so that the pressure P ₁ of air in the local equipment 10 was higher than the pressure P ₂ of air in the clean room 1B by 0.5 mmH ₂ O.

The clean room 1B and the local equipment 1
0 and the air in the local equipment 10 was analyzed in the same manner as in the first embodiment, and the measurement after 7 days and one year of operation time showed that the inorganic substance concentration was the same as in the first embodiment.
No. 1 was obtained, and the concentration of boron (B) was below the detection limit. However, uptime 1 year 2
The concentration of boron (B) was 35 ng / m ^{3 in} the measurement after a month.
The detected concentration increased as the operating time increased. When a local facility equipped with a glass-based air filter is installed in this clean room, the concentration of boron (B) present in the air inside the local facility is 120 ng.
/ M ³ .

In this way, the glass-based air filter 21
When the local equipment 10 is installed in the clean room 1B in which only B is installed 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-based air filter increases. The concentration of inorganic substances contained in the circulating air becomes high. Then, as the operating time increases, when the circulating air having a high concentration of inorganic substances passes through the non-glass air filter 21A of the local facility 10, the inorganic substances in the circulating air easily accumulate in the non-glass air filter 21A. Therefore, the inorganic substances are present in the air inside the local facility 10.

However, in the fourth embodiment, when the operating time is short, it is possible to prevent the inorganic substances from existing in the local equipment 10. Therefore, in the case of short-term use, there is no particular problem. This is suitable because there is no need to install a new pipe in an existing clean room as in the third embodiment.

[0068]

As described above, according to the method of claim 1, the inside of the clean room can be an area where the concentration of inorganic substances is partially reduced, and an expensive non-glass air filter is provided on the entire ceiling. The cost can be kept low as compared with the case of installation.

According to the method of claim 2, since the air contacting the silicon wafer can be made to have a reduced inorganic content, the semiconductor production yield can be improved.

According to the method of claim 3, even if the inside of the clean room is not partitioned at the boundary position of different air filters, it is difficult to direct the air passing through the glass-based air filter to the lower side of the non-glass-based air filter. The inorganic substance concentration below the non-glass type 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 substance concentration below the non-glass-based air filter can be controlled. It can be easily reduced.

According to the clean room of claims 5 and 6, the methods of claims 1 to 4 can be implemented. According to the method of claim 7, the air that has passed through the non-glass air filter doubly is introduced into the local facility, so that the concentration of the inorganic substances in the air in the local facility can be reduced.

According to the method of claim 8, the air in the glass-based air filter side area of the clean room is prevented from directly entering the local equipment without passing through the non-glass-based air filter. Since only the air that has passed through the non-glass type air filter is introduced, it is possible to easily reduce the concentration of inorganic substances in the air in the local facility.

According to the method of claim 9, even if the air that has passed through the glass-based air filter is introduced into the clean room, the fresh air to be introduced into the local equipment is a non-glass-based air filter. Since only those that have passed through, the amount of inorganic substances generated in the local equipment is reduced. That is, according to this method, even if part or all of the air filter to be attached to the clean room is a relatively inexpensive glass-based air filter, the concentration of the inorganic substances in the local facility can be reduced over a long period of time, which is economical. is there.

According to the local facility of the tenth aspect, it is possible to reduce the concentration of inorganic substances in the air in the local facility.

[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 air filters on the ceiling surface of the clean room in FIG.

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

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

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

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

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

[Explanation of symbols]

1 Clean room 2, 2A, 2B Fan filter unit 10 Local equipment 21 Air filter 21A Non-glass type air filter 21B Glass type air filter 6A Non-glass type air filter side area of air introduction route 6B Glass type air filter side area of air introduction route 91 Filter unit (air introduction device) 92 External air conditioner (air introduction device) f ₆ Exhaust fan (exhaust device)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area E04F 17/04 E04F 17/04 A F24F 3/044 F24F 3/044 H01L 21/02 H01L 21/02 D // E04H 5/02 E04H 5/02 B

Claims (10)

[Claims] 1. A method for introducing air into a clean room, wherein a dry air filter for collecting suspended matter in the air is installed on a ceiling of the clean room, and the air passed through the dry air filter is introduced into the clean room. As an air filter, a filter material is a non-glass air filter made of non-glass fiber and a glass material air filter made of glass fiber is placed at a predetermined position on the ceiling, respectively, and the air passing through the non-glass air filter is filtered. The air is introduced into a specified part of the clean room, and 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 so that the air in the glass air filter side area is non-glass. The special feature is that it does not enter the system air filter side area. Air method of introducing into the clean room to be. 2. The method for introducing air into the clean room according to claim 1, wherein the clean room is a semiconductor manufacturing clean room, and the predetermined portion is a place where a silicon wafer is exposed to air. 3. A wind speed of air that is introduced into the clean room through the non-glass air filter is set to be higher than a wind speed of air that is introduced into the clean room through the glass air filter. The method for introducing air into the clean room according to claim 1 or 2, which is characterized. 4. The non-glass type air filter side area is supplied with air from outside the clean room, and the excess air is discharged from the glass type air filter side area to the outside of the clean room. The method of introducing air into the clean room according to item 1. 5. In a clean room in which a dry air filter for collecting suspended matter in the air is installed on a ceiling, a non-glass air filter having a non-glass fiber as a filter medium is arranged at a predetermined position on the ceiling, and other than that. A glass-based air filter whose filter material is made of glass fiber is placed at the position of, 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. The non-glass type air filter side area is connected to an air introducing device for sending air from outside the clean room, and the glass type air filter side area is configured to discharge excess air in the clean room to the outside. 6. An exhaust device for controlling the exhaust gas is connected.
The described clean room. 7. The air introduction into the clean room 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. Method. 8. The pressure of the air introduced into the local equipment through the non-glass air filter of the local equipment is introduced into the clean room in which the local equipment is installed through the glass air filter. A method for introducing air into a local facility, characterized in that the pressure is set higher than the pressure of the generated air. 9. An air introduction device in which a local facility equipped with a non-glass type air filter is installed in a clean room equipped with a glass type air filter, and fresh air from outside the clean room is fed into an air inlet of the local facility. And the excess air in the local equipment
A method for introducing air into a local facility, characterized in that the air is discharged toward at least one of a glass air filter side area of the clean room and the outside of the clean room. 10. A local facility comprising a non-glass air filter as a dry filter.