JPH0444980Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a clean room device, and particularly to one that attempts to achieve uniformity of indoor temperature economically.

[Conventional technology]

In recent years, manufacturing processes in clean rooms have not only been limited to making the room dust-free, but have also become more demanding that the room temperature be uniform both horizontally and vertically. Non-uniform temperature distribution (non-uniformity over distance and over time) in conventional clean rooms is a major problem, especially in ultra-high density semiconductor manufacturing processes. For example, when using a laser length measuring machine used to engrave precise patterns on semiconductors, temperature fluctuations in the indoor air as well as fluctuations in room pressure affect measurement accuracy. Specifically, in 16Mbit DRAM, the minimum line width is about 0.5μm, so the alignment accuracy is required to be 0.1μm.If we apply this condition to the relational expression showing the relationship between temperature and refractive index, for example,
It can be seen that in order to measure a 10 cm long object with an accuracy of 0.1 μm or less, temperature control must be performed with an accuracy of 0.01°C.

By the way, downflow cleanrooms are advantageous in preventing temperature unevenness in clean rooms, but in conventional downflow cleanrooms, circulating air is not mixed sufficiently and temperature unevenness occurs in the cooling coil itself. Therefore, constant temperature has not yet been achieved in terms of spatial distribution and over time.

In order to solve this problem, the method described in Japanese Utility Model Application Publication No. Sho 63-89526 has been proposed.

As shown in FIG. 7, a filter 52 is provided between a plenum chamber 50 and a clean room 51, and a rethane chamber 53 is provided on the floor side of the plenum chamber 50. The plenum chamber 50 and the retentate chamber 53 are connected to the circulation path 54.
A blower 55 and a temperature regulator 56 are provided in this circulation path 54, and the temperature-controlled air is passed through a porous hole installed in a meandering manner opposite to the air flow at the joint to the plenum chamber 50. Plate 57 allows for diffusion mixing within plenum chamber 50 . The blower 55 regulates the temperature of the return air from the clean room 51 and passes it through the filter 52.
The air is blown into the clean room 51 through the air.

[The problem that the idea aims to solve]

However, in the conventional system described above, since the entire amount of circulating air passes through the temperature controller 56, a meandering perforated plate 57 is separately provided to keep the room temperature constant, resulting in a large pressure loss and requiring high blowing power. There is also the problem that the device becomes large in size.

The present invention has been made in view of the above-mentioned matters, and its technical objective is to provide a clean room apparatus that can reduce pressure loss and prevent temperature unevenness within the clean room.

Incidentally, as a prior art, the one described in Japanese Utility Model Application Publication No. 63-57449 is known. As shown in FIG. 8, this uses a fan filter unit 60 instead of a filter, and an air return port 61 is provided near the wall to suck out dust. There is no description of technical matters related to temperature unevenness, which is the object of the present invention, nor is there any description that suggests this. In this type, temperature-controlled air is guided from an air conditioner installed outside the building into the plenum chamber, but the returned air and conditioned air are blown into the plenum chamber without being sufficiently mixed.
The problem of temperature unevenness mentioned above cannot be solved.

[Means to solve the problem]

In order to solve the above technical problem, the present invention takes the following measures.

In the present invention, a plurality of fan filter units 3 each having a fan 2 integrally provided on the upper part of a filter 1 are disposed between a plenum chamber 4 and a clean room 5, and are passed from the plenum chamber 4 side through the filter 1 into the clean room. This is a downflow type clean room device that blows air out to the plenum chamber 5, further suctions the blown air from the retentate chamber 6 side through the circulation duct 13, and circulates the air to the plenum chamber 4 side, and an air-conditioned air supply port 7 is provided on the retentate chamber 6 side. On the other hand, a recirculation air intake 8 is provided on the plenum chamber 4 side to take in a part of the circulating air, and the conditioned air supply port 7 and the recirculation air intake 8 are connected by a duct 9a to separate the air from the air circulation path. A path was formed, and an air conditioner 9 was installed in the middle of the duct to provide a clean room device.

Here, it is more preferable that the conditioned air supply port 7 is a plurality of nozzles disposed within the retentate chamber 6.

Further, as the filter 1, a high performance filter such as a HEPA filter or a ULPA filter, which has excellent dustproof performance, is suitable.

Further, in the above configuration, a plurality of conditioned air supply ports 7 are arranged in the retentive chamber 6, and an automatic opening/closing valve 10 is provided in the air path leading to each conditioned air supply port 7. It is preferable that a temperature sensor 11 is provided in each of the temperature sensors 11 and a controller 12 for controlling the opening degree of the automatic on-off valve 10 based on the temperature detected by the temperature sensor 11.

[Effect]

Clean air is blown out from the plenum chamber 4 to the clean room 5 via the filter 1 by the fan 2 of the fan filter unit 3 installed between the plenum chamber 4 and the clean room 5, and the air in the clean room 5 is sent from the retardant chamber 6 to the circulation duct. 13 and returns to plenum chamber 1. All the power required for air circulation is provided by the fan 2 of the fan filter unit 3.

On the other hand, temperature control is carried out by sucking the air inside the plenum chamber 4 through the recirculation air intake 8 and using the air conditioner 9.
After being subjected to processing such as cooling and heating, it is blown out into the rethane chamber 6. At this time, since the air conditioner 9 is installed outside the air circulation path, there are no obstacles in the circulation duct that would cause pressure loss.

The conditioned air and the recirculated air are mixed in the retardant chamber 6, pass through the circulation duct 13, and flow into the clean room 5 through the fan filter unit 3.

In this way, the path for mixing can be lengthened, and since a large amount of downward flow and the conditioned air are stirred, sufficiently mixed air can be supplied to the clean room 5.

In addition, since the air conditioner 9 only needs to have the ability to compensate for temperature fluctuations caused by heat generation of equipment in the clean room 5, it can be small and economical with less pressure loss due to coils, filters, etc.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 to 6.

<First Example> A first example according to claims 1 and 2 will be described with reference to FIGS. 1 and 2.

The plenum chamber 4 and the clean room 5 are partitioned by fan filter units 3 arranged vertically and horizontally, and the fan filter unit 3 is constructed by integrally providing a fan 2 above a filter 1. As the filter 1, a high-performance filter such as a HEPA filter or a ULPA filter, which has excellent dustproof performance, is used.

A retentate chamber 6 is located under the floor of the clean room 5, and a circulation duct 13 extending from the retentate chamber 6 to the plenum chamber 4 is provided on the side of the clean room 5. The cross-sectional area of this circulation duct 13 is set to 1/5 of the air flow cross-sectional area of the clean room 5.

A total of 25 air-conditioned air supply ports 7 are arranged on the floor surface of the retinue chamber 6, five in each direction.
These conditioned air supply ports 7 face upward.

A recirculation air intake 8 for taking in part of the circulating air is provided on the plenum chamber 4 side, and a duct connecting the recirculation air intake 8 and the conditioned air supply port 7 is arranged outside the building. be. An air conditioner 9 is arranged in the path of this duct to take in a part of the recirculated air and outside air and supply the air to the upper urethane chamber 6 whose temperature and humidity have been adjusted.

Each conditioned air supply port 7 is provided with an automatic opening/closing valve 10, and a temperature sensor 11 is disposed near each conditioned air supply port 7, respectively.

A detection signal from the temperature sensor 11 is sent to a controller 12, and the opening degree of the automatic on-off valve 10 is controlled by a command from the controller 12. As a result, when the temperature rises above a predetermined value (during cooling), the automatic opening/closing valve 10 opens to supply cold air commensurate with the amount of heat generated.

An example of operation will be explained below.

The return flow from the retardant chamber 6 ascends the circulation duct by the fan 2 of the fan filter unit 3 and reaches the plenum chamber 4, where it is removed by the fan 2 of the fan filter unit 3 and clean air is introduced into the clean room 5 in a vertical laminar flow. Supplied with Clean room 5
The downflow flowing into the retan chamber 6 and the conditioned air supplied from the conditioned air supply port 7 are stirred and mixed within the retan chamber 6, while
The fan 2 of the fan filter unit 3 raises the air inside the circulation duct 13 to reduce the temperature difference between the recirculation air and the conditioned air. The air after mixing is blown out into the clean room 5 through the fan filter unit 3 in a uniform flow.

In this way, the mixing path can be lengthened, and sufficiently mixed air can be supplied to the clean room 5 due to the mixing effect caused by rapid expansion upon entering the plenum chamber 4.

Therefore, unlike in the conventional case, temperature distribution within the clean room 5 can be kept uniform without causing temperature unevenness within the clean room 5.

In addition, by adjusting the amount of air-conditioned air blown out from each air-conditioned air supply port 7, it is possible to follow the indoor heat load and prevent temperature changes over time. temperature distribution can be stabilized.

An example of specific numerical values will be explained below. Clean room 5
The volume of is 8 (m) x 8 (m) x 2.7 (m),
The entire surface is a laminar flow type, and the air speed blown from the HEPA fan filter unit 2 is set to 0.4 m/s. In addition, the heat load in clean room 5 is 300Kcal/
^m2・h.

The number of air-conditioned air supply ports 7 in the retinue chamber 6 was 64 in total, with one port per 1 m ² of floor area. The temperature difference of the conditioned air is 5℃, and the air volume is approximately
It was set to 0.06m ³ /s. For example, in a 20 cm square air outlet, the air velocity is 1.5 m/s.

Here, q (calorie Kcal/h) is q=C・r・Q・△θ (However, C・specific heat Kcal/Kg℃, r・specific weight
Kg/m ³ , Q・flow rate m ³ /h, △θ・temperature difference ℃. ) From the above formula, indoor calorific value = 300 x 64 = 0.24 x 1.2 x Q x 5 Q = 13333 m ³ /h = 3.7 m ³ /s Therefore, the air volume per air conditioned air supply port 7 is
From 3.7/64, it becomes 0.06m ³ /s.

<Second example> 3 and 4 show a second embodiment.

In the first embodiment, fine temperature control is possible by adjusting the amount of air-conditioned air blown out from each air-conditioned air supply port 7, but a large number of automatic opening/closing valves 10 and temperature sensors 11 are required. Therefore, high costs are unavoidable.

In this embodiment, five conditioned air supply ports 7 are arranged in a row directly below the circulation duct 13. If a large-capacity one is used as the air-conditioned air supply port 7, the air-conditioning capacity will not decrease, and the automatic opening/closing valve 10
and temperature sensors 11 can be significantly reduced. In this embodiment, the conditioned air supply port 7 is oriented horizontally, facing the recirculation.

Therefore, the structure becomes simple and costs can be reduced. The other configurations and operations are the same as those in the previous embodiment, and will therefore be omitted.

<Third Example> FIGS. 5 and 6 show a third embodiment.

In this example, a nozzle is employed as the conditioned air supply port 7 according to the first aspect. In this example, conditioned air is blown out sideways at high speed, and surrounding air inside the retardant chamber 6 is attracted and mixed. Supply of conditioned air commensurate with the calorific value is carried out through the temperature sensor 11 through the circulation duct 13 or the retan chamber 6.
One location is provided on the circulation duct side of the air conditioner 9, and the detection signal is used to control the flow rate of the cooling coil of the air conditioner 9, thereby preventing temperature changes while maintaining a constant air flow rate.

Such a configuration has the advantage that the automatic on-off valve 10 is unnecessary and only one temperature sensor 11 is required.

The other configurations and operations are the same as those in the previous embodiment, and will therefore be omitted.

[Effect of idea]

According to the present invention, the conditioned air supply port 7 is provided on the retentate chamber 6 side, the recirculation air intake port 8 is provided on the plenum chamber 4 side, and the air conditioner 9 is installed between the conditioned air supply port 7 and the recirculation air intake port 8. Because of this provision, the path through which the air is mixed can be lengthened, and since the large volume of downward flow and the conditioned air are mixed, sufficiently mixed air can be supplied to the clean room 5. .

Therefore, uniformity of air temperature is promoted, and temperature unevenness within the clean room can be suppressed.

Further, unlike the case where the entire amount of circulating air passes through the air conditioner 9, there is less pressure loss, so the equipment can be made smaller and the operating cost is economical.

Further, as shown in claim 2, if the air supply amount of the air conditioned air supply ports 7 arranged in large numbers is individually controlled according to the temperature distribution, fine-grained air conditioning corresponding to the heat generation distribution from the heat generation sources in the clean room is possible. Become.

[Brief explanation of the drawing]

1 to 6 show embodiments of the present invention,
1 is a sectional view of the first embodiment, FIG. 2 is a plan view of the inside of the retentate chamber, FIG. 3 is a side view of the second embodiment, FIG. 4 is a plan view of the inside of the retentate chamber, and FIG.
FIG. 6 is a side view of the third embodiment, FIG. 6 is a plan view of the interior of the retardant chamber, and FIGS. 7 and 8 are sectional views showing a conventional clean room apparatus. 1... Filter, 2... Fan, 3... Clean room, 4... Plenum chamber, 5... Clean room, 6
... Retardant chamber, 7 ... Conditioned air supply port, 8
...Recirculation air intake, 9...Air conditioner, 10...
...Temperature sensor section, 11...Controller, 12...
...Circulation duct.

Claims (1)

[Claims for Utility Model Registration] (1) A plurality of fan filter units 3 each having a fan 2 integrally provided on the top of a filter 1 are arranged between a plenum chamber 4 and a clean room 5, and In a down-flow clean room device that blows air into a clean room 5 through a filter 1, sucks the blown air from the retan chamber 6 side through a circulation duct 13, and circulates the air to the plenum chamber 4 side, an air conditioner is installed on the retan chamber 6 side. An air supply port 7 is provided, and an air intake port 8 is provided on the plenum chamber 4 side to take in a portion of the circulating air, and the air conditioned air supply port 7 and the recirculation air intake port 8 are provided.
A clean room apparatus characterized in that a duct 9a connects the air passages to form an air passage independent of the air circulation passage, and an air conditioner 9 is provided in the middle of the duct 9a. (2) The clean room apparatus according to claim 1, wherein the conditioned air supply port 7 is a plurality of nozzles disposed within the retentate chamber 6. (3) A plurality of conditioned air supply ports 7 are arranged in the retinue chamber 6, and each conditioned air supply port 7 is
An automatic on-off valve 10 is provided in the air path leading to the air, and a temperature sensor 11 is provided near each air-conditioned air supply port 7, and the opening degree of the automatic on-off valve 10 is controlled based on the temperature detected by the temperature sensor 11. 2. The clean room apparatus according to claim 1, further comprising a controller 12 for controlling the clean room.