JP4440754B2 - Exhaust gas abatement system for semiconductor manufacturing equipment - Google Patents

Description

  The present invention relates to an exhaust gas abatement apparatus for a semiconductor manufacturing apparatus that can easily remove dust generated during the abatement of semiconductor exhaust gas.

  In the manufacture of semiconductors such as integrated circuits and liquid crystals, recently, a multi-chamber system having a plurality of chambers is generally adopted as a semiconductor manufacturing apparatus such as CVD because of the need for efficiency improvement and productivity improvement. In that case, specific gases for deposit, purge, and cleaning are used according to the type of process, and each process changes with time and is repeated.

That is, in the semiconductor manufacturing process, the operation of a semiconductor manufacturing apparatus such as CVD is performed by depositing a deposit gas such as SiH ₄ (toxic and explosive hazardous gas for human body) →→ removal of residual SiH ₄ gas in the CVD chamber by nitrogen. Purging →→ Cleaning of the CVD chamber with a cleaning gas such as C ₂ F ₆ (having a greenhouse effect but not harmful) →→ Purging the cleaning gas of the CVD chamber with nitrogen →→ Repeatedly, and so on.

However, in this semiconductor manufacturing process, depending on the type of gas used, if the depositing gas and the cleaning gas are mixed at a certain concentration or more, there is a risk of explosion. As typical examples, SiH ₄ / NF ₃ and SiH ₄ / SF ₆ are known. Therefore, in order to avoid this danger, in addition to purging with nitrogen, the depositing gas and the cleaning gas discharged from the semiconductor manufacturing apparatus are discharged independently from each other regardless of the number of chambers. It was connected and individually detoxified. Therefore, the equipment cost of the abatement apparatus must be increased, and the installation area of the abatement apparatus used in the clean room becomes large.

  In view of this, the present inventor has developed an exhaust gas abatement apparatus that can handle a multi-chamber semiconductor manufacturing apparatus (2) as shown in FIG. 6 (see, for example, Patent Document 1). Specifically, a plurality of independent inlet scrubbers (5a) (5b) with independent pipes (6a) (6b) (6c) in each chamber (1a) (1b) (1c) of the multi-chamber semiconductor manufacturing apparatus (2) (5c) are individually connected, and subsequently, the inner pipes (7a), (7b) and (7c) as heating oxidative decomposition zones provided in the exhaust gas treatment tower (8) are individually connected, and finally the inner pipes are connected. An outlet scrubber (50) for collecting exhaust gases treated in the exhaust gas treatment tower (8) containing the pipes (7a), (7b) and (7c) and cleaning and cooling them in common was provided. The inlet scrubbers (5a) (5b) (5c), the exhaust gas treatment tower (8), and the outlet scrubber (9) have one end communicating with the inside of the chemical tank (T). The inner pipes (7a), (7b) and (7c) are individually separated by the partition wall (9) in the exhaust gas treatment tower (8), individually treated for exhaust gas, and transmitted to each other through the partition wall (9). There is a fever.

As a result, a series of abatement processes proceed in response to the sequential operation of each chamber (1a) (1b) (1c) while shifting the time, so each chamber (1a) (1b) (1c ) Even if the required energy (heat) of the exhaust gas (F) passing through the pipes is different, there is energy exchange between the adjacent inner pipes (7a) (7b) (7c) through the partition wall (9), and individual exhaust gas treatment Exhaust gas treatment chamber (4a) with excess heat to exhaust gas treatment chamber (4a) (4b) (4c) with insufficient heat even if there is a difference in energy generated by treatment reaction between chambers (4a), (4b) and (4c) (4b) Since there is heat transfer from (4c), energy loss can be eliminated compared to the conventional case, and the overall amount of energy required for abatement was successfully reduced.
Japanese Patent No. 3215081

  However, in the exhaust gas abatement apparatus corresponding to the multi-chamber type semiconductor manufacturing apparatus (2) as described above, a large amount of exhaust gas can be removed by a series of abatement processes. The amount of dust also increases. Therefore, when the exhaust gas abatement apparatus is continuously operated for a long time, a large amount of dust becomes sludge and accumulates on the entire bottom of the chemical liquid tank (T). In order to take out the viscous dust deposited on the entire bottom of the chemical tank (T) in this way from the chemical tank (T) during maintenance, connect the pipe connected to the chemical tank (T). All of them must be removed and the chemical tank (T) must be removed from the equipment and cleaned, and it takes time to remove the dust in the chemical tank (T), and the semiconductor manufacturing equipment (2 ) There was a problem that the whole had to be stopped for a long time.

  In addition to the exhaust gas abatement system corresponding to the above-described multi-chamber type semiconductor manufacturing apparatus (2), the 1-channel type exhaust gas abatement system corresponding to a single chamber can be operated in a chemical tank by continuously operating for a long time. As described above, it is difficult to remove the dust.

  The main subject of this invention is providing the waste gas removal apparatus which can remove easily the dust deposited in a chemical | medical solution tank in the case of removal of semiconductor waste gas.

  The invention described in "Claim 1" is a chemical solution tank (60) for storing the chemical solution (W) supplied to the inlet scrubber (40) and collecting the chemical solution (W) discharged from the inlet scrubber (40). And an exhaust gas decomposition treatment chamber (R) that heats and decomposes the cleaning exhaust gas (F) cleaned by the inlet scrubber (40) is formed inside, and decomposed in the exhaust gas decomposition treatment chamber (R). In an exhaust gas abatement apparatus (10) provided with an exhaust gas treatment tower (20) in which an exhaust pipe (62) for discharging exhaust gas (F) is suspended, a chemical liquid stored in the chemical liquid tank (60) ( A step portion (D) for dust storage in which the ceiling surface (65a) is arranged at a position lower than the liquid level (L) of (W) is formed, and the exhaust pipe (62) that hangs down straight is a step portion. The exhaust gas abatement device (10) is characterized in that it communicates with the inside of the chemical tank (60) via (D) ".

  Decomposed exhaust gas (F) with a large amount of dust that is pyrolyzed in the exhaust gas treatment tower (20) and produced as a by-product is discharged from the exhaust gas decomposition treatment chamber (R) through the exhaust pipe (62). . Here, in the present invention, since the exhaust pipe (62) hangs down straight and communicates with the inside of the chemical liquid tank (60), the dust in the decomposed exhaust gas (F) is caught in the middle of the exhaust pipe (62). Most of them fall into the chemical solution (W) stored in the chemical solution tank (60) by their own weight and accumulate in the dust storage step (D). Here, the step part (D) for the dust reservoir is arranged at a position where the ceiling surface (65a) is lower than the liquid level (L) of the chemical liquid (W) stored therein, so that the exhaust pipe ( The dust that has fallen to the step portion (D) via 62) does not have a supernatant and is stored at a high concentration at a relatively small amount of chemical solution and becomes sludge. If the dust sludge in this concentrated portion is taken out, most of the dust sludge in the chemical tank (60) can be taken out, and cleaning is completed in a short time.

  The invention described in "Claim 2" is the exhaust gas abatement apparatus (10) of "Claim 1", wherein "the drainage port (67) is provided at the side or bottom of the step (D) and the chemical tank The bottom surface (64) of (60) is inclined toward the drain port (67) '', which is removed from the exhaust gas (F) by the inlet scrubber (40), and the chemical tank ( Dust that has fallen into the chemical solution of (60) flows down in the direction of the step (D) according to the inclination of the bottom surface (64), and is concentrated and accumulated in the step (D). It is possible to easily remove the dust sludge concentrated and deposited on the stepped portion (D) from the chemical liquid tank (60) through the drain port (67) without removing it from the apparatus. Further, since the extracted concentrated dust sludge has a low water content and a small volume, there is an advantage that the sludge treatment is easy.

  According to the first aspect of the present invention, the dust generated by the thermal decomposition of the exhaust gas can be reliably dropped into the chemical tank, and the amount of the dust dropped into the chemical tank is relatively small. Can be stored in a highly concentrated sludge form in a narrow area. For this reason, the dust in a chemical | medical solution tank can be easily removed only by removing the sludge-like dust deposited on the said part.

  Further, according to the invention described in claim 2, not only dust generated by pyrolysis of exhaust gas but also dust cleaned by the inlet scrubber can be deposited on the stepped portion, and the drain outlet is only opened. Therefore, these dusts can be easily discharged from the drain outlet.

  As described above, according to the present invention, it is possible to provide an exhaust gas abatement apparatus that can easily remove dust accumulated in a chemical tank when a semiconductor exhaust gas is detoxified.

  Hereinafter, the present invention will be described in detail according to illustrated embodiments. 1 and 4 are front and plan conceptual views of a three-chamber compatible exhaust gas abatement apparatus (10) corresponding to, for example, a three-chamber semiconductor manufacturing apparatus (2). (The present invention is merely a representative example of this embodiment, and is naturally applicable to a one-chamber compatible exhaust gas abatement apparatus and the like.) The apparatus (10) of the present invention is generally an inlet scrubber (40a). (40b) (40c), individual piping (6a) (6b) (6c) connecting these with the chamber (1a) (1b) (1c), exhaust gas treatment tower (20), outlet scrubber (50), and chemical tank (60).

  In the figure, (2) is a semiconductor manufacturing apparatus such as CVD, and (1a), (1b) and (1c) are chambers provided in the semiconductor manufacturing apparatus (2). And the exhaust gas in the chamber (1a) (1b) (1c) is exhausted to independent pipes (6a) (6b) (6c) for independent exhaust gas introduction by exhaust pumps (3a) (3b) (3c), The exhaust gas introducing independent pipes (6a), (6b), and (6c) are connected to independent inlet scrubbers (40a), (40b), and (40c), respectively.

  The inlet scrubber (40a) (40b) (40c) and the exhaust gas treatment tower (20) are installed in this order on the chemical tank (60), and the outlet scrubber (50) is located on the downstream side of the chemical tank (60). The scrubber body (53) is installed on the chemical tank (51). Although not shown, of course, the chemical solution tank and the chemical solution tank are integrated, and the water in the chemical solution tank and the water in the chemical solution tank are partitioned by a partition wall that can supply water from the chemical solution tank to the chemical solution tank by overflow. You may leave it.

Each inlet scrubber (40a) (40b) (40c) is equipped with a spray nozzle (41a) (41b) (41c) for injecting chemical liquid (W) such as water or alkaline liquid, and the spray nozzle (41a) ( 41b) (41c), a mist-like high-pressure chemical solution (W), which contains a large amount of dust such as SiO ₂ and hydrolyzable substances such as SiF ₄ and F ₂ contained in the exhaust gas (F) Water soluble components are removed by washing. Each inlet scrubber (40a) (40b) (40c) is a straight straight pipe, and is installed upright on the top surface of the chemical tank (60), and its bottom surface opens to the chemical tank (60). The removed component falls into the chemical tank (60) as it is. The bottom openings (42a) (42b) (42c) are separated by partition walls (61a) (61b) (61c) which will be described in detail in the explanation of the chemical tank (60).

  The chemical tank (60) is in the shape of a rectangular box, and its interior is divided into three zones (α) (β) (γ) on the supply side and exhaust side in this case by the partition walls (61a) (61b) (61c) as described above. It is divided into 1 zone (δ), and the bottom opening (42a) (42b) (42c) of the aforementioned inlet scrubber (40a) (40b) (40c) in each supply side zone (α) (β) (γ) Is open. The upper ends of the partition walls (61a) (61b) (61c) are hermetically welded to the ceiling surface (65) of the chemical tank (60), but the lower ends thereof are washed water (or alkali or acid) of the chemical tank (60). Although it is immersed in other chemicals), it is separated from the bottom surface (64), and the cleaning water in the chemical tank (60) can freely move between each zone (α) (β) (γ) (δ). Come and go.

  An overflow tank (63) is installed in the chemical liquid tank (60) so that the water level (namely, the liquid level (L)) in the chemical liquid tank (60) is constant. The water overflowing from the overflow tank (63) is discharged from the overflow outlet (66).

  In addition, in the portion corresponding to the exhaust side zone (δ), the ceiling surface (65 b) is a step portion for dust storage arranged at a position lower than the liquid level (L) of the chemical liquid (W) stored therein ( D) is formed, and an exhaust pipe (62) to be described later is connected to the ceiling surface (65a).

  Furthermore, a drainage port (67) is provided below the side surface of the step (D), and the bottom surface (64) is a drainage port (so that the sludge-like dust accumulated at the bottom can be easily discharged. It is formed to be inclined downward toward 67).

  In addition, in the three zones (α), (β), and (γ), the submerged nozzles (68a), (68b), and (68c) are individually arranged, and the three zones (α), (β), and (γ) are passed through. Water is sprayed toward the flowing exhaust gas (F) and at the same time, water is sprayed on the inner wall of the three zones (α) (β) (γ) to form a water film on the inner wall of the three zones (α) (β) (γ). The component is protected from the corrosive component in (F).

  In addition, the inner surface of the inlet scrubber (40a) (40b) (40c) and the chemical tank (60) and other parts other than the processing tower body (21) of the present embodiment are included in the semiconductor exhaust gas (F). Or in order to protect each part from corrosion by corrosive components such as hydrofluoric acid generated by decomposition of exhaust gas (F), corrosion resistant lining and coating with FRP, vinyl chloride, polyethylene, unsaturated polyester resin and fluororesin are applied. Yes.

  The exhaust gas treatment tower (20) is roughly composed of a treatment tower main body (21) constituting a casing and a cylindrical heating element (30a) (30b) (30c), and each of the inlet scrubbers (40a) (40b) ) (40c) is connected to the cylindrical heating element (30) through the aforementioned three zones (α), (β), and (γ).

  The cylindrical heating element (30) is cylindrical, and a heating element (H) embedded in a cylindrical member, a cylindrical ceramic heater, or the like is used.

  Here, the cylindrical heating element (30) passes through the bottom (22) of the processing tower body (21) described later, and the ceiling surface of each zone (α) (β) (γ) of the chemical tank (60) ( It is connected to α1) (β1) (γ1) and takes in the exhaust gas (F) flowing from each zone (α) (β) (γ).

  The schematic structure of the treatment tower body (21) is made of a steel-made cylindrical outer jacket (21a), a heat and corrosion resistant lining member (21b) such as Hastelloy, and the outer jacket (21a) and lining member ( 21b), and an exhaust gas decomposition treatment chamber (R) is formed inside the lining member (21b). The lining member (21b) covers the entire inner periphery of the exhaust gas decomposition treatment chamber (R), and the lining member (21b) is in direct contact with the thermally decomposed exhaust gas (F).

  A bottom portion (22) is integrally attached to the bottom surface of the exhaust gas treatment tower main body (21), and both are detachably attached by a fastener. A cooling unit (23) is provided at the bottom of the exhaust gas treatment tower main body (21) to store cooling water (24). The cooling water (24) is supplied by a water supply pipe (25) provided on the side surface of the cooling unit (23), and the spiral water flow is a morning glory shape (conical truncated conical shape) that is the outer wall portion of the cooling unit (23). It flows down while swirling along the cooling wall (23a). Although the cooling wall (23a) is preferably like Hastelloy, it is always covered with the water film of the spiral water flow, so it may be a corrosion resistant stainless steel plate whose surface is covered with the FRP layer or the resin layer. .

  The bottom (22) of the exhaust gas treatment tower body (21) is made of Hastelloy or a corrosion-resistant stainless steel plate whose surface is covered with an FRP layer so as to surround the lower end of the cylindrical heating element (30). A formed protective wall (27) is provided, and the cooling water (24) is accumulated between the protective wall (27) and the cooling wall (13). This portion is referred to as a cooling water reservoir (28). The cooling water (24) overflows the protective wall (27) and flows into the exhaust pipe (62).

  In addition, rotating arms (35a) (35b) (35c) connected to the motor (M) are suspended from the ceiling portion of the exhaust gas treatment tower main body (21), and the dust wiping arm (four branches) ( The dust adhered to the inner and outer surfaces of the cylindrical heating elements (30a), (30b), and (30c) is removed by 36a), (36b), and (36c). The dust is in the form of extremely fine cotton dust, and falls by simply touching the rotating dust removal arm (36a) (36b) (36c).

  Since the cylindrical heating elements (30a), (30b), and (30c) are straight straight pipes, most of the dust falls into the chemical tank (60) without being caught on the way.

  At the bottom (22) of the exhaust gas treatment tower main body (21) corresponding to the exhaust zone (δ) of the chemical liquid tank (60), the exhaust pipe (62) extends from the bottom (22) to the step (D) of the chemical liquid tank (60). It is provided straight toward. A cracked gas supply pipe (69) is connected to the side surface of the exhaust pipe (62), and is connected to the upper part of the chemical tank (51) of the outlet scrubber (50). In addition, a water pipe (52) is connected to the bottom of the chemical tank (51) below the liquid level (L) of the chemical tank (61), and the chemical liquid (W) in the chemical tank (51) is connected to the chemical tank (61). ).

  The outlet scrubber (50) is for finally removing harmful components in the heat-decomposed exhaust gas (F) .A chemical tank (51) is installed at the lower end of the outlet scrubber (50). A straight pipe type scrubber body (53) is connected. In this scrubber main body (53), a plurality of perforated plates (54) in the vertical direction (two stages in this embodiment) are sprayed, and a chemical solution is sprayed toward the lower surface of the perforated plate (54). Directly above the upper spray nozzle (55) and the uppermost perforated plate (54), it is downwardly sprayed with cleaning water (or chemical) from above so as to face the flow direction of the semiconductor exhaust gas (F) Spray nozzle (56) (see FIG. 5).

  Here, the perforated plate (54) is a plate-like member attached so as to cross the entire interior space of the scrubber body (53), and a small gas passage for allowing the semiconductor exhaust gas (F) to flow therethrough. A number of flow holes (54a) are formed. The perforated plate (54) is preferably a punching metal or a net.

  A mesh member (57) having an opening smaller than the gas flow hole (54a) of the perforated plate (54) is provided below the spray nozzle (56) attached to the lowermost part inside the scrubber body (53). It is installed across the entire space.

  The outlet scrubber (50) is erected on the chemical tank (51) for storing the chemical liquid (W) such as cleaning water or alkaline liquid (or although not shown, the chemical tank provided separately) And the chemical liquid (W) sprayed from the spray nozzle (56) is gas-exhausted into the exhaust gas (F) fed through the cracked gas feed pipe (69). The liquid comes into contact and is fed into the chemical tank (51).

  The spray nozzle (56) is supplied with a new chemical cleaning solution (W) such as fresh water instead of the circulating chemical solution in the chemical solution tank (51). The top outlet of the outlet scrubber (50) is connected to an exhaust fan (70) that discharges the treated exhaust gas (F) into the atmosphere.

Next, the operation of the exhaust gas abatement apparatus (10) shown in FIG. 1 will be described. In a semiconductor manufacturing process, particularly a CVD (Chemical Vapor Deposition) process, C ₂ F ₄ , CF _4, and CHF ₃ are used to clean the CVD chamber after the deposition with a deposition gas such as SiH ₄ is completed as described above. Cleaning with a cleaning gas such as perfluorocarbon (hereinafter referred to as “PFC”) such as NF ₃ or a fluorine compound not containing carbon such as NF ₃ is performed.

  However, depending on the type of gas used as described above, there is a combination in which there is a risk of explosion if the depositing gas and the cleaning gas are mixed at a certain concentration or more. Therefore, in order to avoid this danger, different chambers (1a) (1b) (1c) are used for each gas, and individual inlet scrubbers (40a) (40b) via independent pipes (6a) (6b) (6c) (40c) Separately supplied and individually washed with spray nozzles (41a) (41b) (41c), and separation zones (α) (β) corresponding to the individual inlet scrubbers (40a) (40b) (40c) The exhaust gas (F) is supplied to the individual cylindrical heating elements (30a), (30b), and (30c) through (γ). In the individual inlet scrubber (40a) (40b) (40c), it comes into contact with the atomized chemical liquid (alkaline liquid, acidic liquid or water) sprayed from the spray nozzle (41a) (41b) (41c), and exhaust gas (F) The dust inside is brought into contact with the fine droplets dispersed and captured and sent to the chemical tank (60). At the same time, water-soluble components in the exhaust gas (F) are absorbed and removed into the chemical solution.

  In the separation zone (α) (β) (γ), water is constantly blown to the inner surface of the separation zone (α) (β) (γ) by the watering nozzles (68a) (68b) (68c) to form a water film. Thus, the corrosive exhaust gas (F) is prevented from coming into contact with the inner surface of the separation zone (α), β, and γ and corroding it. In addition, since the separation zones (α), β, and γ extend horizontally with respect to the individual inlet scrubbers 40a, 40b, and 40c installed vertically, the exhaust gas (F) When flowing from the inlet scrubber (40a) (40b) (40c) into the separation zone (α) (β) (γ), the flow direction is changed, turbulence is generated and at the same time the watering nozzle (68a) (68b) ( The dust in the exhaust gas (F) is efficiently collected by spraying from 68c) and falls into the chemical tank (60) together with the spraying.

The low-temperature wet exhaust gas (F) that has passed through the separation zone (α) (β) (γ) individually rises in the cylindrical heating elements (30a), (30b), and (30c), where it is oxidatively decomposed during the rise. However, when SiH ₄ (silane) is contained in the exhaust gas (F), as described above, the cylindrical heating element (30) in which the SiH ₄ (silane) flows flows upward from the middle. It is mainly decomposed at the part heated to 400-600 ° C to generate a large amount of dust.

Generated dust, such as SiO _2, is automatically removed by the dust removal arm (36a) (36b) (36c) of the rotary arm (35a) (35b) (35c) and falls into the chemical tank (60). And gather. In the exhaust gas abatement apparatus (10) of the present embodiment, the bottom surface (64) of the chemical tank (60) is provided in a downward slope toward the step portion (D) provided with the drain port (67). Dust removed by the dust wiping arms (36a), (36b) and (36c) is also collected in the space provided with the step (D) of the chemical tank (60).

  Since the cylindrical heating element (30) incorporates the heating element (H) inside as described above, the heat from the heating element (H) heated to a temperature slightly higher than the decomposition temperature passes through the inner cylindrical wall. The atmosphere in the narrow through-hole that becomes the reaction space in the cylindrical heating element (30) is heated to the decomposition temperature or higher. The exhaust gas (F) is directly heated and oxidatively decomposed without passing through heat loss while passing through the through holes that form the narrow reaction space of the cylindrical heating element (30).

  In addition, there is heat radiation from the outer peripheral surface of the cylindrical heating element (30), a high temperature zone is formed in the vicinity of the ceiling part (21H) of the exhaust gas treatment tower body (21), and the cylindrical heating element (30) exits. If undecomposed components remain in the exhaust gas (F), they are finally decomposed in this high temperature zone.

  As described above, the gas processed in the cylindrical heating element (30) and the high temperature zone is sucked by the atmospheric discharge fan (70) and is discharged through the exhaust pipe (62) and the cracked gas supply pipe (69). It is led into the chemical tank (51) of the scrubber (50), and when it passes through the outlet scrubber (50), it is cleaned and cooled with gas, and is released into the atmosphere.

  Here, in the exhaust gas abatement apparatus (10) of the present embodiment, the exhaust pipe (62) hangs down straight and is connected to the ceiling part (65a) of the step part (D), and the inside of the chemical liquid tank (60) Therefore, the dust in the cracked exhaust gas (F) is not caught in the middle of the exhaust pipe (62), and most of the dust goes into the chemical liquid (W) stored in the chemical liquid tank (60) by its own weight. It falls and accumulates on the step (D). Since the ceiling (65a) of the step (D) is lower than the level of the chemical (W) stored in the chemical tank (60), the supernatant liquid does not enter the step (D) and the exhaust pipe (62 The dust that has fallen to the step portion (D) via) is accumulated at a high concentration at a relatively small amount of chemical solution and becomes sludge. Therefore, the dust in the chemical tank (60) can be easily removed simply by removing the sludge-like dust accumulated on the portion. If a drainage port (67) is provided at the side or bottom of the step (D), the high-concentration dust sludge accumulated on the step (D) can be taken out from the drainage port (67), and the chemical tank ( 60) need not be taken out from the device (10), and maintenance becomes extremely easy. In addition, since the extracted dust sludge does not contain much water, the bulk is small, and subsequent sludge treatment becomes easy.

  In addition, since the bottom surface (64) of the chemical tank (60) is provided in a downward slope toward the drain port (67), dust or the like removed from the exhaust gas (F) by the inlet scrubber (40) is also stepped ( In this respect, it is not necessary to take out the chemical tank (60) from the apparatus (10).

  In the above-described embodiment, an example of the exhaust gas abatement device (10) corresponding to the multi-chamber semiconductor manufacturing device (2) is shown, but the step portion (D) is formed in the chemical tank (60). In addition, as long as the exhaust pipe (62) hanging down straight communicates with the inside of the chemical tank (60) via the step (D), it may correspond to a single chamber.

  In addition, the case where the drainage port (67) is provided on the lower side of the side surface of the stepped portion (D) has been shown, but sludge-like dust accumulated on the stepped portion (D) can be easily removed simply by opening the drainage port (67). As long as it can be discharged, the installation location of the drain port (67) is not limited to this, and may be provided, for example, on the bottom surface (64) side of the stepped portion (D).

Schematic conceptual diagram of the device of the present invention Schematic conceptual diagram of the processing tower main body part of FIG. Plane schematic conceptual diagram of FIG. Cross-sectional view of an exhaust gas treatment tower of one embodiment used in the present invention Sectional perspective view of an outlet scrubber of an embodiment used in the present invention. Schematic conceptual diagram of a conventional example

Explanation of symbols

(1a) (1b) (1c) ... Chamber
(2)… Semiconductor manufacturing equipment
(6a) (6b) (6c) ... Individual piping
(10)… Exhaust gas abatement system
(20)… Exhaust gas treatment tower
(21) ... Processing tower body
(30a) (30b) (30c) ... Cylindrical heating element
(40a) (40b) (40c) ... Inlet scrubber
(50) ... Exit scrubber
(60)… chemical tank
(62) ... Exhaust pipe
(64)… Bottom
(65I)… Ceiling surface
(67)… Drain outlet
(F)… Exhaust gas
(H) ... heating element
(D) ... Step
(L) ... Liquid level
(W)… Chemical solution
(R)… Exhaust gas decomposition treatment chamber

Claims (2)

A chemical tank for storing the chemical supplied to the inlet scrubber and collecting the chemical discharged from the inlet scrubber;
Exhaust gas in which an exhaust gas decomposition processing chamber for heating and thermally decomposing the cleaning exhaust gas washed with water at the inlet scrubber is formed, and an exhaust pipe for discharging the exhaust gas decomposed in the exhaust gas decomposition processing chamber is vertically disposed A processing tower,
In an exhaust gas abatement device equipped with
In the chemical tank, a dust storage step having a ceiling surface disposed at a position lower than the liquid level of the chemical stored in the interior is formed, and the exhaust pipe hanging straight down is provided through the step. An exhaust gas abatement apparatus that communicates with the inside of the chemical liquid tank.   2. The exhaust gas abatement apparatus according to claim 1, wherein a drainage port is provided at a side portion or a bottom portion of the stepped portion, and a bottom surface of the chemical solution tank is inclined toward the drainage port.

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