JPH11166757A - Clean room - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make air flows in a clean room uniform even when the number of filters is remarkably reduced by providing wind vanes immediately below fan filter units and making part of the air discharged vertically downward from the fan filter units to flow to the outsides of area below the fan filter units. SOLUTION: When wind vanes 10 are installed to fan filter units 4 having a width D, L=αD, and H=βD, where, α=3, and β=1/3 θ=45 deg., the air flows in the area below the ceiling between the fan filter units 4 become eddy-free smooth flows. In addition, the uniformity of the air flows in the areas immediately below the units 4 are also improved and a nearly uniform flow velocity distribution is obtained. When the installed angle θof the wind vanes 10 are set about 40 deg.-60 deg., the uniformity of the flow velocity distribution at a height of 2.5 D from a grating floor can be improved effectively. Since the air flows can be made uniform throughout a clean room without using any partition wall, etc., the layout change of a semiconductor manufacturing device can be carried out easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clean room for forming a clean room for installing a production facility such as a semiconductor factory.

[0002]

2. Description of the Related Art Conventional techniques for reducing initial costs and running costs of a clean room include:
There is a technique disclosed in JP-A-62-5031.
This separates the clean room with a glass partition wall,
In areas where high cleanliness is required, such as in semiconductor manufacturing equipment and automatic transfer robots, a high-performance filter is installed on the entire ceiling to use a laminar flow system, and in other areas that do not require high cleanliness, high performance is used. A turbulent flow system is provided by providing a filter partially on the ceiling. As a result, the number of high-performance filters in a region that does not require high cleanliness can be reduced, and the capacity of the blower can be reduced by that amount, so that initial costs and running costs can be reduced.

[0003] In addition, if an airflow region such as a vortex exists in a clean room of a clean room, gas and dust that may cause wafer contamination tend to accumulate in that region, so that the airflow in the clean room is as uniform as possible. It is desirable that As a conventional technique for eliminating the above-mentioned vortex region and making the air flow uniform (laminar flow), Japanese Patent Application Laid-Open No.
There is a technique disclosed in Japanese Patent No. 294440. this is,
A filter duct for ceiling is provided at a required interval on a filter duct for a corner of a ceiling attached to a ceiling and a side wall of a clean room, and a rectifying member which also serves as a holding device for lighting equipment is provided at substantially the center of both filter ducts.

[0004] Both filter ducts are provided with a high-performance filter which is curved so that clean air flows in any of the downward, oblique and lateral directions. Therefore, the clean air blown from the filter in the lateral direction is guided downward by the rectifying member, and the clean air blown in the diagonal direction joins from both and goes downward, and goes directly to the floor, and these are integrated. And a uniform air flow (laminar flow) can be formed.

[0005]

However, the prior art disclosed in Japanese Patent Application Laid-Open No. 62-5031 has the following problems. First, the number of filters cannot be significantly reduced. In the clean room, various semiconductor manufacturing equipment and the like are arranged very densely, and the area that requires high cleanliness accounts for a large proportion of the floor area of the entire clean room. Even if the filter of the area not to be reduced is reduced, at most 20
The reduction is only about 30%.

[0006] Second, it is difficult to cope with a change in the layout of the manufacturing apparatus. Since the partition wall is used, when the layout is to be changed, it is necessary to remove the partition wall and then move the semiconductor manufacturing apparatus, which complicates the construction.

The prior art disclosed in Japanese Patent Application Laid-Open No. 63-294440 has the following problems. First
Is that it is difficult to keep the blowing speed of the clean air constant in the longitudinal direction of the filter duct. This is not a problem in a small clean room where the length of the filter duct is short.However, in a recent large-scale clean room, the length of the filter duct is long, so the flow velocity near the inlet of the filter duct is large and the The flow velocity near the tip becomes small.

[0008] Second, the cost for the filter duct is increased. In order to make the clean air flow downward, obliquely, and laterally, the high-performance filter needs to be installed in a curved state. Therefore, in the case of a large-scale clean room, the cost for manufacturing the filter duct is considerably high.

An object of the present invention is to provide a low-cost clean room which can make the air flow in a clean room uniform even if the number of filters is significantly reduced, and which can easily cope with a layout change of a semiconductor manufacturing apparatus.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide a clean room in which production equipment and the like are installed, a lower floor room separated from the clean room by a grating floor having an opening ratio located below the clean room, and a clean room. A plurality of fan filter units for ventilation and dust removal located above the room in a row in the longitudinal direction, a ceiling room separated from a clean room by a ceiling plate arranged at a constant interval in the lateral direction, In a clean room having a return duct for forming a circulating airflow from the underfloor room to the ceiling room, a wind direction plate is provided immediately below the fan filter unit, and a part of air discharged vertically downward from the fan filter unit is used as a fan. The air is allowed to flow outside the lower area of the filter unit, and the ratio of the width of the wind direction plate on the lower surface of the fan filter unit to the width of the fan filter unit is determined. Substantially equal to the ratio between the Tsu-wide and fan filter unit installation interval is achieved by further 40 to 60 degrees the direction of the wind direction plate from vertically downward.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view of a clean room according to an embodiment of the present invention. The air in the ceiling chamber 2 flows into the fan filter unit 4 from the air inlet 6 of the fan filter unit 4 installed on the ceiling of the clean room 1 and is boosted by the blower 5 installed in the fan filter unit 4. , After being removed by the high-performance filter 7,
It flows into the clean room 1 and then the grating floor 9 of the clean room 1
And flows into the underfloor chamber 3 through the return duct 8 and returns to the ceiling chamber 2 to form a circulating flow.

FIG. 2 is an enlarged view of the vicinity of the fan filter unit 4. As shown in FIG. 2, the wind direction plate 10 is located at the position of the wind direction plate installation width H, symmetrically with respect to the center line of the fan filter unit 4, and from the vertically downward direction at the wind direction plate installation angle θ.
It is installed in the direction of. As a result, the air flowing into the clean room 1 from the fan filter unit 4 is discharged from the inner portion of the wind direction plate installation width H to a region below the fan filter unit 4, and the ceiling without the fan filter unit 4 from the outside of the wind direction plate. Released into the lower area of the plate.

Here, the installation interval of the fan filter unit 4 is defined as L, and the width of the fan filter unit is defined as D. In this embodiment, a plurality of fan filter units 4 are arranged in a row in the longitudinal direction over the entire surface of the ceiling, and the fan filter units 4 are arranged at intervals L in the lateral direction. The wind direction plate 10 according to the present embodiment does not need to be subjected to processing such as bending, and may be a simple plate-shaped member. Therefore, the clean room according to the present embodiment can be realized at low cost.

Next, the effect of the wind direction plate 10 in the present invention will be described.
The result confirmed by the numerical simulation will be described.
FIG. 3 shows a model diagram of a clean room in which a numerical simulation was performed. The right end of the figure is the symmetry boundary, and the calculation was performed only for the left half of the room. As shown in the figure, the size of the room is, assuming that the width D of the fan filter unit 4 is 1, the width of the return duct 8 is 2.5, the half width of the clean room is 25, the height of the clean room is 6, and the height of the underfloor room is 7 It is. As shown in FIG. 3, the installation interval L of the fan filter unit 4 and the wind direction board installation width H were L = αD, H = βD, and the simulation was performed using α, β and the wind direction board installation angle θ as parameters.

FIG. 4 shows a flow velocity vector diagram when α = 3 and the wind direction plate 10 is not installed. As can be seen from FIG.
Vortices are generated in the area below the ceiling between the fan filter units 4. FIG. 5 shows that α = 3, β = 1/3, θ =
It is a flow velocity vector diagram at the time of installing the wind direction board 10 at 45 degrees. Unlike FIG. 4, there is no vortex in the area under the ceiling between the fan filter units 4 and the flow is smooth.

FIG. 6 shows the calculation results of the vertical flow velocity component w of the 2.5 D portion above the grating floor 9 corresponding to the section AA in FIG. 3 with the case where the distance from the wall is X and there is no wind direction plate. 7 is a graph comparing the case where β = １ ／, １ ／, and １ ／ with the wind direction plate. As mentioned earlier, wind direction plate 1
If there is no 0, the flow velocity in the area immediately below the fan filter unit 4 is high, and the flow is uneven. On the other hand, when there is a wind direction plate, the non-uniformity is improved in each case.

In particular, β = 1/3 (that is, H = D / 3)
In the case of, it is understood that the flow velocity distribution is substantially uniform. This is because the flow rate of the air flowing out of the fan filter unit 4 in the area below the ceiling surface where the fan filter unit 4 is not provided depends on the area of the ceiling surface and the fan filter unit 4.
This is because H / D and D / L are equal to each other. Therefore, in the present invention, it is most effective that H / D = D / L. In the above calculations, the flow velocity of air blown from the fan filter unit 4 was set to 0.35 m / s.

FIG. 7 shows a simulation result of the flow velocity distribution at the same position as FIG. 6 when α = 3, β = 1/3 and the wind direction plate installation angle θ is changed to 30 °, 45 °, and 60 °. . In each case, the flow condition is shown in FIG.
As shown in (1), the flow became smooth without vortices between the fan filter units. But on the grating floor 2.
As can be seen from the figure, the uniformity of the flow velocity distribution of 5D is almost uniform when θ = 45 ° and 60 °,
In the case of = 30 °, it became slightly uneven. Therefore,
In the present invention, it is effective to set the wind direction plate installation angle θ to about 40 ° to 60 °.

FIG. 8 shows that θ = 45 °, β = 1 / α, and α =
FIG. 7 shows a simulation result of the flow velocity distribution at the same position as in FIG. 6, comparing a case where the wind direction plates are not installed with α = 3 and β = 1/3 and a case where the wind direction plates are set to 3, 4, and 5; α = 4,
In the case of 5, the magnitude of the average flow velocity in the clean room 1 is α = 3
So that the fan filter unit 4
The flow velocity of the clean air blown out from is set large.

As can be seen from FIG. 8, when α = 5, there is almost the same nonuniformity of the flow velocity distribution as when no wind direction plate is installed, but when α = 3, 4, the inside of the clean room The airflow can be made almost uniform. Therefore, the number of fan filter units 4 can be reduced by 67% when α = 3 and by 75% when α = 4, as compared with the case of the entire laminar flow method.

As described above, Japanese Patent Application Laid-Open No. Sho 62-5031
In the prior art disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, only 20 to 30% can be reduced, so that the number of fan filter units 4 can be significantly reduced as compared with the prior art, and the initial cost and running cost can be reduced accordingly. it can. However, in order to reduce the number of fan filter units 4 and maintain the cleanliness in the clean room 1, α =
As the blowout flow rate in the case of 4, 5 was set large,
It is necessary to increase the capacity of one blower by that much, but when flowing air with the same flow rate in general, it is more efficient to use a small number of large capacity blowers than to use many small capacity blowers, Running costs do not increase.

Further, according to the present invention, since the air flow can be made uniform throughout the clean room without using a partition wall or the like,
Even when the layout of the semiconductor manufacturing apparatus is changed, it can be easily handled.

Further, it is considered that the above-described effects regarding the installation width and the installation angle of the wind direction plate depend on the flow speed of air blown from the fan filter unit 4. Is generally 0.3 to 0.3 due to the degree of cleanliness in the clean room 1.
Since the Reynolds number, which is a dimensionless number representing the flow properties, does not change significantly in this flow velocity range, the effect of the present invention can be generally expected in a practical flow velocity range. it is conceivable that.

In this embodiment, two wind direction plates 10 are provided for one fan filter unit 4, but the same effect can be expected even if two or more wind direction plates 10 are provided. However, in this case, it is effective that the installation width of the two innermost sheets when viewed from the center line of the fan filter unit 4 is H / D = D / L as shown above.

Generally, the fan filter unit 4
Is composed of a blower 5, a high-performance filter 7, and an air intake 6, but the same effect can be expected even if the wind direction plate of the present invention is incorporated in the fan filter unit 4.

[0026]

According to the clean room of the present invention, when the number of fan filter units is reduced, the air flow in the clean room can be changed to a laminar state having a uniform flow velocity distribution without vortices. -A clean room that can reduce running costs and can easily cope with a layout change of a semiconductor manufacturing apparatus can be realized.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a clean room according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the vicinity of a fan filter unit according to the embodiment of the present invention.

FIG. 3 is a model diagram of a simulation performed for confirming the effects of the present invention.

FIG. 4 is a flow velocity vector diagram in the vicinity of a fan filter unit when a wind direction plate is not installed.

FIG. 5 is a flow velocity vector diagram near a fan filter unit when a wind direction plate is installed.

FIG. 6 is a comparison of the flow velocity distribution in a clean room when the installation width of the wind direction plate is changed.

FIG. 7 is a comparison of the flow velocity distribution in a clean room when the wind direction plate installation angle is changed.

FIG. 8 is a comparison of the flow velocity distribution in a clean room when the fan filter unit installation interval is changed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Clean room 2 ... Ceiling room 3 ... Underfloor room 4 ... Fan filter unit 5 ... Blower 6 ... Air intake 7 ... High-performance filter 8 ... Return duct 9 ... Grating 10 ... Wind direction board

Claims (3)

[Claims] 1. A clean room in which a production facility or the like is installed, a lower floor room separated from the clean room by a grating floor having an opening ratio located below the clean room, and a clean room located above the clean room. A plurality of fan filter units for ventilation and dust removal are arranged in a row in the longitudinal direction, a ceiling room partitioned from the clean room by a ceiling plate arranged at a constant interval in the lateral direction, and from the underfloor room. And a return duct for forming a circulating airflow leading to the ceiling room, in a clean room, a wind direction plate is provided directly below the fan filter unit to be inclined from vertically downward, and air discharged vertically downward from the fan filter unit. Characterized in that a part of the clean room flows outside the lower region of the fan filter unit along the wind direction plate. 2. The method according to claim 1, wherein the ratio of the width of the wind direction plate to the width of the fan filter unit on the lower surface of the fan filter unit is substantially equal to the ratio of the width of the fan filter unit to the installation interval of the fan filter unit. The clean room according to claim 1, wherein 3. The direction of the wind direction plate is from 40 to 40 from a vertical downward direction.
The clean room according to claim 1 or 2, wherein the angle is set to 60 degrees.