JPH0899014A - Exhaust gas treatment device - Google Patents

Abstract

(57) [Abstract] [Purpose] In an exhaust gas treatment device, it is possible to maintain the exhaust capacity for a long time and operate it without cleaning the perforated plate 2. [Structure] Two through holes 14 and 15 are formed at substantially the same position.
A means for changing the effective area of the effective through hole 10 in which the sliding plate 2a and the fixed plate 2b, which are a single plate member, are arranged so as to overlap each other to form the perforated plate 2 and the through holes 14 and 15 are overlapped, respectively. A cleaning liquid 3 for the gas provided on the perforated plate 2 and introduced.
Even if the reaction product produced by the gas-liquid contact adheres to the periphery of the effective through-hole 10 and lowers the conductance, the position of the sliding plate 2a is moved to increase the area of the effective through-hole and raise the conductance, thereby increasing the inside of the tower. Maintain a higher pressure than the back pressure and operate stably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treating apparatus for removing harmful substances from a gas produced from a semiconductor manufacturing apparatus and discharging the harmless gas.

[0002]

2. Description of the Related Art Conventionally, there is a leak shelf type exhaust gas treatment apparatus as a typical one of this type of exhaust gas treatment apparatus. This leaking shelf type exhaust gas treatment device has been widely used as an exhaust gas treatment device for semiconductor manufacturing equipment because the construction cost is relatively low.

FIGS. 4 (a) and 4 (b) are a schematic cross-sectional view of an exhaust gas treatment apparatus showing an example of the prior art and an enlarged view of a portion B. As shown in FIG. For example, as shown in FIG. 4 (a), the leak shelf type exhaust gas treatment apparatus stores a cleaning liquid 3 below and sprays the cleaning liquid 3 from above.
And a tower 8 having a gas inlet 5 and a gas outlet 6, and a perforated plate 12 having a plurality of through holes in the tower 8 and having a plurality of through holes through which the sprayed cleaning liquid 3 passes. And an exhaust fan 4 for exhausting gas introduced into the tower 8. Further, as shown in FIG. 4B, the perforated plate 12 has a large number of through holes of about 8 mm in a circular plate.

The operation of this exhaust gas treatment apparatus is as follows. First, when the gas generated from the semiconductor manufacturing apparatus is introduced from the gas inlet 5, the gas is guided into the tower 8 by the exhaust fan 4 and the through hole of the perforated plate 12 is introduced. When it passes through, it comes into countercurrent contact with the cleaning liquid 3 discharged from the spray nozzle 1 at the through hole. When the gas comes into contact with the cleaning liquid 3, the harmful substances contained in the gas are absorbed and the detoxified gas is released from the gas outlet 6 to the atmosphere.

[0005]

In the above-mentioned conventional leak-shelf type exhaust gas treatment apparatus, as the operation is repeated, the produced quality grows due to the chemical reaction between the cleaning liquid and the introduced gas, and FIG. As shown in, the scale 7 is accumulated around the through hole. As a result, the opening area of the through hole becomes smaller, the back pressure rises, the flow rate of the exhaust gas that can be treated decreases, and the treatment capacity decreases. Further, as the growth of the scale 7 progresses, the pressure in the tower on the gas inlet side becomes a negative pressure with respect to the back pressure, so that the exhaust wind speed of the gas exhaust hood of the semiconductor manufacturing equipment cannot be obtained. There is a problem of leaking from the hood or causing a dangerous situation.

In order to prevent this, at present, the scale is grown one by one by stopping the apparatus and dropping the scales 7 grown by hand. However, this operation is a dangerous operation that wastes a lot of time, and has a problem that the operation rate of the semiconductor manufacturing apparatus is also reduced.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an exhaust gas treating apparatus capable of maintaining and operating the exhaust capacity for a long time without cleaning the perforated plate.

[0008]

A feature of the present invention is that a tower having a gas inlet for introducing a gas by arranging a spray nozzle for storing a cleaning liquid and spraying the cleaning liquid from above, and an inside of the tower. A plurality of first gas
An exhaust gas treatment apparatus comprising: a perforated plate having a through hole and arranged in a plurality of stages; and an exhaust fan for bringing the gas introduced into the tower into contact with the cleaning liquid and exhausting the gas from a gas outlet of the tower. The exhaust gas treatment apparatus is provided with an effective area varying means for changing the effective area of the perforated plate through which the gas in the first through hole can pass according to the pressure in the tower on the gas inlet side.

Further, the opening area varying means is arranged such that at least two plate members having a plurality of second through holes at substantially the same position are overlapped and the plate members are displaced from each other. Therefore, it is preferable that the mechanism changes the effective area of the first through hole formed by the overlap of the respective second through holes.

Further, in addition to the opening area varying means, it is preferable that a driving mechanism for periodically rubbing the overlapping plate members with each other is provided.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

1 (a), 1 (b) and 1 (c) are schematic cross-sectional views showing an exhaust gas treating apparatus in one embodiment of the present invention and a top view (b) and a cross-sectional view showing an enlarged portion A of a perforated plate. It is a figure. As shown in FIG. 1, the exhaust gas treatment apparatus includes an effective area variable mechanism that changes the effective area through which the gas in the effective through hole 10 can pass through the perforated plate 2 according to the pressure in the tower 8 on the gas inlet side. ing.

This effective area variable mechanism is provided with through holes 14 and 1.
Slide plate 2a and fixed plate 2b having 5 in substantially the same relative position
And the sliding plate 2a with respect to the fixed plate 2b.
Is a mechanism for changing the effective area of the effective through-hole 10 formed by overlapping the respective through-holes 14 and 15 with each other.

This effective area variable mechanism also inputs a pressure gauge 9 for detecting the pressure in the tower 8 on the gas inlet 5 side, and inputs the pressure value of this pressure gauge 9 and compares it with the back pressure to lower the reference value. A control circuit 11 which gives an output to the motor 13 in accordance with the decrease value, and a feed screw (not shown) which is connected to the motor 13 for feeding a nut (not shown) attached to the end of the sliding plate 2a. And a feeding mechanism composed of.

Next, the operation of the exhaust gas treatment device will be described. First, gas exhausted from a semiconductor manufacturing apparatus such as a CVD apparatus is introduced into the tower 8 from the gas inlet 5. The gas blown and introduced by the exhaust fan 4 passes through the effective through holes 10 of the multi-stage perforated plate 2 and is discharged from the gas discharge port 6 while being in gas-liquid contact with the cleaning liquid 3 sprayed from the spray nozzle 1. You. By this gas-liquid contact, harmful substances contained in the gas are adsorbed by the cleaning liquid 3 and dropped below the tower 8.

On the other hand, during operation, the pressure gauge 9 constantly monitors the pressure of the introduced gas. Here, after driving for a long time,
If a scale is generated in the effective through hole 10 and the pressure value of the pressure gauge 9 falls below the reference value, the control circuit 11 amplifies the analog value of the value below the reference value, converts it into a digital signal value, and converts it. The digital pulse number is sent to the motor 13. Then, the motor 13 rotates according to the number of pulses sent, and the sliding plate 2a slides on the fixed plate 2b by the rotation of the feed screw, the overlapping degree of the through holes 14 and 15 changes, and the effective area of the effective through hole 10 changes. To increase. As a result, the conductance of the effective through hole 10 of the perforated plate 2 increases, and the pressure value of the pressure gauge 9 increases.

Then, the pressure gauge 9 is monitored again, and the effective area of the effective through hole 10 is increased each time the pressure value falls below the reference value. When the movement limit is reached mechanically, the perforated plate 2 is cleaned as in the related art. As a result, it is possible to increase the operation rate of the semiconductor manufacturing apparatus by that amount, which was conventionally cleaned and inspected every two months only once a year.

FIGS. 2A and 2B are diagrams showing examples of various effective through holes of the perforated plate of FIG. In the above-mentioned embodiment, the effective through hole is an elliptical shape having a high conductance coefficient, but rather it is found that it is more effective to form a turbulent flow in the gas flow and make it difficult for the reactant to adhere. Obtained. For example, as shown in FIG. 2A, this effective through hole is formed by overlapping a diamond-shaped effective through hole 10a formed by overlapping triangular through holes or a rectangular through hole shown in FIG. 2B. A rectangular effective through hole to be formed may be considered.

FIG. 3 is a schematic sectional view showing a half of a tower portion in another embodiment of the exhaust gas treatment apparatus of the present invention. In this exhaust gas treatment apparatus, as shown in FIG. 3, a drive mechanism for periodically moving the overlapping fixed plate 2 and sliding plate 2a is provided separately from the above-described effective area variable mechanism. The drive mechanism includes a connecting rod 17 connected to the fixed plate 2b, and an air cylinder 16 connected to the connecting rod 17 via a piston rod 16a.

This drive mechanism operates only for a short time when the semiconductor manufacturing apparatus is temporarily stopped, and is stopped while the above-mentioned effective area variable mechanism is operating. Then, the reciprocating motion of the air cylinder 16 causes the sliding plate 2a stopping the fixed plate 2b to perform a rubbing operation to remove the reaction substances adhering to the inside without stacking.

By providing this drive mechanism, the period for cleaning is extended, and maintenance is free once every several years.

[0022]

As described above, according to the present invention, two plate members having through holes formed at substantially the same position are superposed and arranged to form a perforated plate. By providing a means capable of changing the effective area of the through hole in this perforated plate, even if the reaction product generated by the gas-liquid contact of the cleaning gas of the introduced gas adheres around the effective through hole and reduces the conductance, By moving the position of the plate member, the area of the effective through hole can be enlarged, the frequency of maintenance in the conventional work of removing the scale to which the perforated plate adheres is reduced, it can be operated continuously for a long time, and the semiconductor in the previous stage There is an effect that the operation rate of the manufacturing apparatus can be improved.

Further, by providing a mechanism for periodically rubbing the two plate members together, the adhered reaction product can be removed as required, so that the maintenance free effect is obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view (a) showing an exhaust gas treatment device in one embodiment of the present invention, a top view (b) and a cross-sectional view (c) showing an enlarged portion A of a porous plate.

FIG. 2 is a view showing examples of various effective through holes of the perforated plate of FIG.

FIG. 3 is a schematic sectional view showing a half of a tower section in another embodiment of the exhaust gas treatment apparatus of the present invention.

FIG. 4 is a schematic cross-sectional view of an example of a conventional exhaust gas treatment apparatus and an enlarged view of a portion B.

[Explanation of symbols]

 1 Spray Nozzle 2, 12 Perforated Plate 2a Sliding Plate 2b Fixed Plate 3 Cleaning Liquid 4 Exhaust Fan 5 Gas Inlet 6 Gas Outlet 7 Scale 8 Tower 9 Pressure Gauge 10, 10a, 10b Effective Through Hole 11 Control Circuit 13 Motor 14, 15 Through Hole 16 Air Cylinder 16a Piston Rod 17 Connecting Rod

Claims (3)

[Claims] 1. A tower having a spray nozzle for storing a cleaning solution below and spraying the cleaning solution from above and having a gas suction port for introducing a gas, and a plurality of first towers in the tower through which the gas passes. An exhaust gas treatment apparatus comprising: a perforated plate having a through hole and arranged in a plurality of stages; and an exhaust fan for bringing the gas introduced into the tower into contact with the cleaning liquid and exhausting the gas from a gas outlet of the tower. The exhaust gas treatment apparatus is provided with an effective area varying means for changing an effective area through which the gas in the first through hole can pass, in accordance with the pressure in the tower on the gas inlet side. 2. The opening area varying means includes at least two plate members having a plurality of second through holes at substantially the same position in a stack, and the plate members are displaced from each other. 2. The exhaust gas treating apparatus according to claim 1, wherein the exhaust gas treating apparatus is a mechanism for changing the effective area of the first through hole formed by overlapping the respective second through holes. 3. The exhaust gas treating apparatus according to claim 2, further comprising a drive mechanism for periodically rubbing the overlapping plate members with each other.