JP6718566B1 - Exhaust gas abatement unit - Google Patents

Abstract

The clogging of the exhaust gas path from the foreline piping to the pyrolysis tower is greatly eliminated. The exhaust gas abatement unit (U) includes a vacuum pump (1), an exhaust gas introduction nozzle section (20), and an exhaust gas cleaning section (40). The exhaust gas introduction nozzle part (20) includes an exhaust gas nozzle (21), a protective gas nozzle (25) forming a protective gas curtain (Gk) enclosing the exhaust gas (H) from the exhaust gas nozzle (21), and a protective gas curtain (Gk). ) Is included in the water ejection nozzle (27). The exhaust gas cleaning unit (40) includes the water tank (41) and the stirring unit (46). The water tank (41) is a hollow container having water (M) for cleaning stored therein, and the exhaust gas introducing nozzle section (20) is connected to the water tank (41). The space between the water (M) in the water tank (41) and its ceiling (41a) is a flow space (45) through which the exhaust gas (H) flows. The stirring unit (46) is vertically installed from a ceiling portion (41a) of the water tank (41), and a lower portion thereof is immersed in water (M) in the water tank (41), and the first weir (47). The second weir (48) is provided downstream of the weir (47) and the upper part thereof is exposed above the water (M). [Selection diagram] Figure 2

Description

The present invention relates to an exhaust gas abatement unit that detoxifies exhaust gas discharged from a manufacturing process of electronic devices such as semiconductors and liquid crystals and releases it to the atmosphere, and more specifically, in an exhaust gas passage due to dust and reaction products contained in the exhaust gas. This relates to an exhaust gas abatement unit that can significantly reduce clogging in piping and equipment.

In the manufacturing process of electronic devices such as semiconductors and liquid crystals, various kinds of harmful or highly flammable/explosive gases with a high degree of danger and global environment-destroying gases causing ozone holes are used. Examples of the global environmental destruction gas include perfluoro compounds such as CF ₄ and C ₂ F ₆ used as a cleaning gas for a CVD chamber and carbon-free fluorine compounds such as NF ₃ (hereinafter, Gases of various compounds, including "PFC").

In an electronic device manufacturing plant, a manufacturing apparatus such as CVD and a mechanical booster pump are generally installed in a clean room on the upper floor, and a screw vacuum pump, an inlet scrubber, a pyrolysis tower, an outlet scrubber are provided on the lower floor. A series of exhaust gas abatement devices including the above are individually installed and connected by piping (Patent Documents 1 and 2).
Then, the process chamber of the manufacturing apparatus on the upper floor and the screw type vacuum pump on the lower floor are connected by piping via a mechanical booster pump, and the exhaust gas in the process chamber is sucked by the vacuum pump. .. The exhaust gas emitted from the process chamber contains a reaction product component generated in the device manufacturing process (for example, a water-soluble component or a hydrolyzable gas that reacts with moisture to generate a large amount of dust).

In the lower floor, it is installed following the vacuum pump, and the exhaust gas discharged from the vacuum pump is washed with water by a shower to remove the water-soluble components and hydrolyzable components and to collect dust generated by the reaction. An inlet scrubber for collecting, a water tank for containing cleaning water flowing out from the inlet scrubber, a thermal decomposition tower installed on the water tank for thermally decomposing the water-cleaned exhaust gas, and generated in the thermal decomposition tower However, an outlet scrubber for removing the reaction product components (acidic components, dust, etc.) contained in the detoxified exhaust gas is connected in this order by pipes.

Known thermal decomposition towers for removing exhaust gas include a thermal decomposition type that decomposes exhaust gas with the heat of an electric heater (Patent Document 2) and a plasma type that performs plasma decomposition treatment by passing the exhaust gas through a plasma space. (Patent Document 3).

JP, 2016-33364, A JP, 11-333247, A Japanese Patent No. 5307556

As described above, the exhaust gas sometimes contains a hydrolyzable component, which is discharged from the process chamber and flows into the exhaust gas abatement equipment at the downstream side. It reacts with water to produce a reaction product, which adheres to and grows in the pipe or the inner surface of the equipment, and finally causes a clogging accident that clogs the exhaust gas flow passage in any part.

With conventional exhaust gas abatement equipment, users purchase equipment such as vacuum pumps, inlet scrubbers, thermal decomposition towers, outlet scrubbers, water tanks for cleaning water recovery, and their connecting pipes individually, and at their own electronic device manufacturing plant. It was assembled inside. In this case, there were the following problems.
(1) Since the individual devices constituting the exhaust gas abatement equipment are arranged separately and connected by pipes, the installation area of the exhaust gas abatement unit is likely to expand.
(2) The user purchased the above equipment and connecting pipes individually while checking the performance, but if purchased separately, it would be difficult to unify the maintenance management of the entire equipment, and if there are weak points, Maintenance is required intensively, making maintenance difficult. For example, a pipe called a foreline that connects a process chamber of an electronic device manufacturing apparatus and an inlet scrubber via a vacuum pump, a hydrolyzable component contained in exhaust gas reacts with shower water of the inlet scrubber, and the Reaction products accumulate and block the shower outlet in a short time, or the water of the shower water reversely permeates the exhaust gas flowing in the foreline pipe and reacts in the foreline pipe, and reacts on the inner surface of the foreline pipe. There is a problem in that the product adheres and grows and blocks the foreline pipe in a short time.
(3) Further, when the exhaust gas from the process chamber is washed with water, a large amount of dust is generated, which is brought into the pyrolysis tower together with the washed exhaust gas, which may cause clogging inside the pyrolysis tower.

The present invention has been made in view of the above problems of the conventional system, and the first problem is to substantially eliminate the clogging of the exhaust gas path from the foreline pipe to the pyrolysis tower, thereby achieving long-term continuous operation. The second challenge is to build an exhaust gas abatement unit under the design concept that all components are unified, and to integrate these into one housing, to achieve the consolidation of the installation area. It is to realize space saving.

In order to solve the above problems, the exhaust gas abatement unit U of the present invention (Claim 1) includes a vacuum pump 1 for sucking the exhaust gas H from the process chamber 201 of the semiconductor manufacturing apparatus 200, and an exhaust gas from the vacuum pump 1. The exhaust gas introducing nozzle part 20 for washing the exhaust gas H with water and the impurities contained in the cleaning exhaust gas H washed with water and discharged from the exhaust gas introducing nozzle part 20 are collected, and the cleaning exhaust gas H is subjected to the next exhaust gas decomposition. Including an exhaust gas cleaning unit 40 sent to the process,
The exhaust gas introducing nozzle unit 20 forms an exhaust gas nozzle 21 for introducing the exhaust gas H into the exhaust gas cleaning unit 40 and a protective gas G enclosing the exhaust gas H ejected from the exhaust gas nozzle 21 to form a protective gas curtain Gk. A protective gas nozzle 25, and a moisture ejection nozzle 27 enclosing the protective gas curtain Gk ejected from the protective gas nozzle 25,
The exhaust gas cleaning unit 40 includes the water tank 41 and a stirring unit 46,
The water tank 41 is a hollow container that extends in the horizontal direction and stores water M for cleaning therein, and an inlet 41c for introducing the exhaust gas H to which the outlet of the exhaust gas introducing nozzle portion 20 is connected, the water M and its ceiling portion. 41a, and a flow space 45 through which the exhaust gas H flows and is sent to the exhaust gas decomposition step,
The stirring unit 46 is hung from the ceiling 41a of the water tank 41, the lower portion thereof is immersed in the water M in the water tank 41, and the first weir 47 having an exhaust gas passage 47a in the immersion portion, and the first weir 47 Exhaust gas H that has passed through the exhaust gas passage 47a is installed downstream of the first weir 47 via a stirring region 49 that stirs the water M, and an upper portion of the second weir 48 is exposed above the water M. It is characterized by including.

According to this, the contact of the exhaust gas H ejected from the exhaust gas nozzle 21 with the moisture M from the water ejection nozzle 27 is blocked within the range protected by the protective gas curtain Gk, so that the exhaust gas H is added. The reaction product such as dust produced by the reaction between the decomposable component and the moisture M does not adhere to the exhaust gas nozzle 21 and block the exhaust gas nozzle 21, or the exhaust gas H flowing through the exhaust gas nozzle 21. The reverse osmosis does not block the exhaust gas passage upstream of the exhaust gas nozzle 21.

Then, the cleaning exhaust gas H exiting from the exhaust gas introducing nozzle unit 20 is introduced into the water tank 41 of the exhaust gas cleaning unit 40, and is agitated together with the water M in the water tank 41 by the agitating unit 46, so that dust contained in the exhaust gas and other Contaminants are effectively collected in the water M and sent to the next step as cleaning exhaust gas H containing no contaminants.
In the present invention, the term “water” includes water, fog, steam, water sprinkling, etc., and all of them are indicated by the symbol M.

According to claim 2, in the exhaust gas abatement unit U of claim 1,
The exhaust gas introduction nozzle unit 20 is installed at a position where the exhaust gas H jetted from the exhaust gas nozzle 21 and the moisture M from the moisture jet nozzle 27 collide with each other beyond the protective gas curtain Gk at a position separated from the exhaust gas nozzle 21. It is characterized in that it further includes a scattering member 30 for colliding H, the protective gas G and the water M and scattering them.

As a result, the gas-liquid contact between the exhaust gas H and the water M is efficiently performed, and most of the hydrolyzable components in the exhaust gas H are decomposed here, and a large amount of dust is generated.

Claim 3 is the exhaust gas abatement unit U according to claim 1 or 2,
The vacuum pump 1 is installed below the mechanical booster pump 2 connected to the first foreline pipe P 1 drawn from the process chamber 201 of the semiconductor manufacturing apparatus 200 and the mechanical booster pump 2 and pulled out from the mechanical booster pump 2. And a roughing pump 4 connected to the second foreline pipe P2,
An exhaust gas introducing nozzle unit 20 is connected to the third foreline pipe P3 drawn from the roughing pump 4,
It is connected to the first foreline pipe P1, and when cleaning the semiconductor manufacturing apparatus 200, the fluorine radicals F· are supplied into the first foreline pipe P1 so that the first foreline pipe P1 and below, and the exhaust gas introducing nozzle portion 20. An inner surface cleaning unit 10 for removing the inner surface deposit S of the constituent members including
The second foreline pipe P2 is connected to the second foreline pipe P2, and the cleaning water M is supplied after the inner surface cleaning with the fluorine radicals F. The inner surface deposit S is washed with water, and then, the dry gas G is supplied to the second foreline pipe P2 and the inner surface cleaning unit 16 for drying the inner surface of the component member including the exhaust gas introducing nozzle unit 20. It is characterized by being configured.

Thereby, the inner surfaces of the first foreline pipe P1 and below and the components including the exhaust gas introducing nozzle portion 20 are simultaneously cleaned at the time of cleaning the semiconductor manufacturing apparatus 200, and the maintenance time can be shortened.

According to claim 4, in the exhaust gas abatement unit U according to claim 1,
The vacuum pump 1, the exhaust gas introduction nozzle unit 20, the exhaust gas cleaning unit 40, and the thermal decomposition tower 60 for thermally decomposing the cleaning exhaust gas H from the exhaust gas cleaning unit 40 and the decomposition exhaust gas H from the thermal decomposition tower 60 are washed with water to An outlet scrubber 80 that removes impurities in the decomposed exhaust gas H generated by thermal decomposition and discharges the decomposed exhaust gas H as clean exhaust gas H, a piping system that connects the constituent devices, and a housing that houses these And 90.

According to this, since the constituent devices for removing exhaust gas and the piping system thereof are housed together in one housing 90, the installation area can be made compact as compared with the conventional case. Since a series of exhaust gas abatement component devices are prepared by the same manufacturer, the performance of the exhaust gas abatement unit U as a whole is harmonized, and the dust clogging of the foreline piping system, which was originally a weak point, can be eliminated. done.

As described above, according to the present invention, the exhaust gas H does not contain dust and other contaminants in cooperation with the moisture jet nozzle 27 of the exhaust gas introduction nozzle unit 20 and the stirring unit 46 of the exhaust gas cleaning unit 40 in the next step. Can be sent to.
Since the abatement equipment and the piping system are integrated according to a unified design concept and these are housed in one housing 90, the installation area of the exhaust gas abatement unit U can be saved, and at the same time for the user, the exhaust gas It has become possible to comprehensively manage from the entrance to the exit of the abatement unit U.

It is a front view which shows the internal structure of the exhaust gas abatement unit to which this invention is applied. It is a functional explanatory view of the component of FIG. 1, and the enlarged view of the stirring part (weir). (A) It is a schematic sectional drawing of 1st Example of the inner surface cleaning part of this invention, (b) It is a schematic sectional drawing of the 2nd Example. It is sectional drawing of the exhaust gas introduction nozzle part of this invention. It is sectional drawing of the thermal decomposition tower of this invention. It is sectional drawing of the exit scrubber of this invention.

The present invention will be described below with reference to the illustrated embodiments. The exhaust gas abatement unit U includes a vacuum pump 1 (wherein an exhaust gas H discharged from a manufacturing apparatus 200 used in a semiconductor device manufacturing process, for example, a CVD film forming apparatus is installed in a housing 90 of the exhaust gas abatement unit U ( It is a facility that sucks in the mechanical booster pump 2 and the roughing pump 4), sequentially sends the exhaust gas H to the devices housed in the same housing 90, thermally decomposes it, detoxifies it, and releases it to the atmosphere.
In the description of the background art, the removal of PFC exhaust gas has been described as a representative example, but since the persistent exhaust gas is not limited to PFC exhaust gas, the gas to be treated in the present invention is simply exhaust gas H.

Hereinafter, an example of an embodiment of the exhaust gas abatement unit U of the present invention will be described with reference to the drawings. The exhaust gas abatement unit U is installed, for example, in a factory for manufacturing semiconductor products, liquid crystal panels, etc., on the floor below the clean room 210 in which the semiconductor manufacturing apparatus 200 is installed and below the clean room 210. Configure 200 exhaust systems.

The exhaust gas abatement unit U of the present invention includes a vacuum pump 1, an inner surface cleaning unit 10, an inner surface cleaning unit 16, an exhaust gas introduction nozzle unit 20, an exhaust gas cleaning unit 40, a thermal decomposition tower 60, an outlet scrubber 80, and a piping system connecting these. It is configured with a housing 90 that stores these.
The semiconductor manufacturing apparatus 200 is provided with a process chamber 201 for performing a liquid crystal panel, a semiconductor wafer film forming process, an etching process, and the like. The exhaust gas abatement unit U is installed on the floor below it as described above.

The vacuum pump 1 includes a mechanical booster pump 2 used as an upper pump for exhausting the process chamber 201, and a roughing pump 4 (for example, a dry pump or a screw pump) as a lower pump.
As can be seen from FIG. 1, the mechanical booster pump 2 is mounted on the shelf 91 of the housing 90, and the roughing pump 4 is mounted immediately below it on the water tank 41 of the exhaust gas cleaning unit 40 described later.

In the present embodiment, the first foreline pipe P1 drawn from the process chamber 201 penetrates the floor 220 and is connected to the mechanical booster pump 2 below.
Then, the mechanical booster pump 2 and the roughing pump 4 are connected by the second foreline pipe P2, and further, the exhaust gas introducing nozzle portion 20 is installed in the third foreline pipe P3 drawn from the roughing pump 4. ing.

In the present invention, the mechanical booster pump 2 and the roughing pump 4 are arranged vertically in the housing 90, and the exhaust gas introducing nozzle portion 20 is arranged just beside the roughing pump 4. The pipe lengths of the second foreline pipe P2 and the third foreline pipe P3 are extremely short.
Then, the second foreline pipe P2 is formed in a J shape as can be seen from FIG. 1, the upper end thereof is connected to the mechanical booster pump 2, and the bottom portion of the second foreline pipe P2 is connected to the roughing pump 4, The inner surface cleaning unit 16 is connected to the connector P2c at the end of the second foreline pipe P2 facing in the direction, which will be described later.

The inner surface cleaning section 16 is attachable to and detachable from the connector P2c provided at the end of the second foreline pipe P2. When the inner surface cleaning unit 16 is not connected, the connector P2c of the second foreline pipe P2 is closed, and the inner surface cleaning unit 16 is connected during the internal cleaning.

The first foreline pipe P1 is provided with an inner surface cleaning unit 10 that produces fluorine radicals to gasify the adhered substances S on the inner surfaces of the pipes and devices below the first foreline pipe P1 and remove them. The second foreline pipe P2 is provided with an inner surface cleaning section 16 for supplying water M for cleaning and heated inert gas G for drying to the pipes and equipment below the second foreline pipe P2.

The inner surface cleaning unit 10 includes a radical generation chamber 12, a high frequency coil 13, and a high frequency power supply 14.
The radical generation chamber 12 is a hollow cylindrical member having openings provided on both end surfaces in the longitudinal direction, and an opening provided on one end surface is an inlet opening portion 12a and an opening provided on the other end surface is an outlet opening portion 12b. To do.
The radical generation chamber 12 is attached to the first foreline pipe P1 when it is connected in series to the first foreline pipe P1 as shown in FIG. 3(a) and when it is connected to the outlet as shown in FIG. 3(b). It may be connected to the first foreline pipe P1 via the opening 12b.
In the radical generation chamber 12 of FIG. 3A, the first half of the first foreline pipe P1 is connected to the inlet opening 12a at the upper end in the longitudinal direction, and the first foreline pipe P1 is connected to the outlet opening 12b at the lower end. The latter half of is connected. Then, a cracked gas supply pipe 12c for supplying a cracked gas for adhering substances in the pipe (for example, NF ₃ ) is connected to the first half portion of the first foreline pipe P1.
In the case of FIG. 3B, the decomposition gas supply pipe 12c is connected to the inlet opening 12a of the radical generation chamber 12.
Further, an arrow generated in the loop portion 13a of the radical generation chamber 12 and emerging from the outlet opening 12b indicates a fluorine radical F·.

The radical generation chamber 12 is made of a metal such as stainless steel (SUS) or Hastelloy (registered trademark), or a ceramic such as SiO ₂ or Al ₂ O ₃ , which is excellent in airtightness, heat resistance, corrosion resistance and mechanical strength. It is a cylindrical member composed of.

A high frequency coil 13 is disposed inside the radical generating chamber 12. The high frequency coil 13 is a cylindrical loop coil formed by spirally winding a wire made of a conductive metal such as copper or stainless steel. The high-frequency coil 13 is provided inside the radical generation chamber 12 so that the central axis of the loop portion 13a, which is spirally wound and has a cylindrical space inside, and the central axis of the radical generation chamber 12 are coaxial. Is attached to. Further, both ends of the loop portion 13 a of the high frequency coil 13 extend from the inside of the radical generation chamber 12 to the outside and are connected to the high frequency power supply 14.
The high-frequency coil 13 and the radical generation chamber 12 described above are preferably cooled as needed to prevent overheating.
The points shown inside the first foreline pipe P1 and the radical generation chamber 12 indicate the inner surface deposit S. Reaction products accompanying the exhaust gas H from the process chamber 201 are attached to the inner surface of the first foreline pipe P1 connected to the process chamber 201.

The high frequency power supply 14 is a power supply that applies a high frequency voltage to the high frequency coil 13.

The inner surface cleaning unit 16 that is connected to the connector P2c of the second foreline pipe P2 as needed is composed of a water supply pipe 18 for cleaning and a dry gas supply pipe 19, and the water supply pipe 18 for cleaning and dry gas supply A common pipe 17 with the pipe 19 is connected to the connector P2c provided at the lower end of the J-shaped second foreline pipe P2 in accordance with the inner surface cleaning by the fluorine radicals F. Open/close valves 18v and 19v are attached to the water supply pipe 18, the dry gas supply pipe 19 and the common pipe 17, respectively.
Clean city water M (or water M in the water tank 41) is supplied from the water supply pipe 18, and heated inert gas (nitrogen) G is supplied from the dry gas supply pipe 19 in this embodiment.

The exhaust gas introduction nozzle unit 20 is a device connected to the outlet of the third foreline pipe P3 extending from the outlet of the roughing pump 4. First, the exhaust gas introducing nozzle portion 20 reversely osmulates the exhaust gas H sent from the roughing pump 4 and enters the reaction product S inside the third foreline pipe P3 and the pipes and equipment upstream thereof. Is required, and secondly, the function of hydrolyzing the hydrolyzable components contained in the exhaust gas H by spraying the water M is required. This will be described below.

Next, the exhaust gas introducing nozzle portion 20 is composed of a casing 35, a triple pipe 20a mounted on a ceiling portion of the casing 35, and a scattering member 30 provided immediately below the triple pipe 20a.
The nozzle structure of the triple pipe 20a is an exhaust gas nozzle 21 which is an inner pipe, and an intermediate pipe which surrounds the exhaust gas nozzle 21, and injects an inert gas G to form a protective gas curtain Gk around the exhaust gas H. The protective gas nozzle 25 and an outer tube surrounding the protective gas nozzle 25 are constituted by a water jet nozzle 27 that jets water from the outside of the protective gas curtain Gk.

The inlet portion of the exhaust gas nozzle 21 is connected to the third foreline pipe P3 drawn from the roughing pump 4. The longitudinal cross-sectional shape of the inner surface of the exhaust gas nozzle 21 is formed into a thick circular straight tube from the inlet portion to the middle portion, and is narrowed so that the inner diameter gradually decreases from the middle portion toward the exhaust gas outlet 21f which is the outlet. ing. It is preferable that the exhaust gas ejection port 21f is formed in a knife-edge shape so that reaction products and dust do not adhere and accumulate. An inverted frustoconical portion on the outer surface of the exhaust gas nozzle 21 that gradually decreases toward the exhaust gas ejection port 21f becomes the inner surface of the gap that forms the protective gas ejection passage T1 through which the protective gas G is ejected.

The protective gas nozzle 25 is formed with a cylindrical storage recess 25b opening at the center of the upper surface, and a tapered (funnel-shaped) nozzle hole 25a is formed downward from the center of the storage recess 25b. .. The portion where the nozzle hole 25a is provided is referred to as a nozzle portion 25c. The nozzle portion 25c is hollow and has an inverted truncated cone shape.
The front end opening of the protective gas ejection passage T1 is a protective gas ejection port 25f and surrounds the entire circumference of the exhaust gas ejection port 21f. A protective gas supply pipe 26 is connected to the upper side surface of the protective gas nozzle 25 and communicates with a gas reservoir 26a formed between the inner surface of the storage recess 25b and the outer surface of the exhaust gas nozzle 21. That is, the gas reservoir 26a communicates with the protective gas ejection passage T1 that reaches the protective gas ejection port 25f. The protective gas ejection port 25f projects in the exhaust gas ejection direction from the exhaust gas ejection port 21f.

The water jet nozzle 27 is provided so as to surround the entire circumference of the protective gas nozzle 25.
The nozzle portion 27 c of the water jet nozzle 27 is formed in a tapered conical shape formed with the same taper as the nozzle portion 25 c of the protective gas nozzle 25, and is formed between the outer peripheral surface of the protective gas nozzle 25 and the inner peripheral surface of the water jet nozzle 27. A gap that forms the moisture ejection passage T2 is formed therebetween over the entire outer peripheral surface of the protective gas nozzle 25.
The water ejection passage T2 is connected to the water supply pipe 28 via the water reservoir 28a. The water supply pipe 28 is connected to the first pumping pipe 42, and the water M in the water tank 41 is supplied by the first pumping pump YP1 installed in the first pumping pipe 42.
In FIG. 4, the water supply pipe 28 is connected to the side surface of the water jet nozzle 27 and is connected to the water pool 28a.

The triple pipe 20a is installed in the casing 35, and the scattering member 30 is installed below the nozzle opening of the triple pipe 20a. The scattering member 30 includes a dish-shaped portion 31, a support member 34 attached to the casing 35, and a leg portion 32. The dish-shaped portion 31 is a circular and shallow dish-shaped member, and the periphery of the upper surface is raised. The inside of the raised edge 31b is hollow. This recessed portion is referred to as a collision portion 31a. The distance between the collision portion 31a and the tip of the nozzle opening of the protective gas nozzle 25 is preferably a point where moisture (heating steam or fine water droplets) ejected from the moisture ejecting nozzle 27 breaks through the protective gas curtain Gk, or a lower position beyond this point. .. When the collision portion 31a is brought too close to the nozzle opening of the protective gas nozzle 25, the moisture shielding effect of the protective gas curtain Gk is impaired.

The support member 34 is a disk-shaped member and is fixed to the inner surface of the casing 35. An exhaust gas downflow hole 33 is formed at an appropriate position of the support member 34. The upper ends of the cylindrical legs 32 are attached to the center of the bottom of the dish 31. The lower end of the leg portion 32 is attached to the center of the support member 34.

The casing 35 is formed of a cylindrical body having an opening on the lower surface, and the triple pipe 20a is attached downward to the ceiling portion thereof as described above. The lower surface opening is attached to an exhaust gas H introduction opening 41c of a water tank 41 described later.

The exhaust gas cleaning unit 40 is a hollow container that extends in the horizontal direction, and has a water tank 41 in which cleaning water M is stored at a certain height, and one or a plurality of stirring units provided in the water tank 41. 46 and one to a plurality of injection nozzles 50. As the stirring unit 46, a weir having a high gas-liquid contact effect by stirring the water M is used (enlarged view of FIG. 2 ).

A flow space 45 through which the exhaust gas H flows is provided between the ceiling 41a of the water tank 41 and the cleaning water M. In the water tank 41 of the present embodiment, a weir structure is adopted as the stirring section 46 in the present embodiment in order to enhance gas-liquid contact between the exhaust gas H flowing in the flow space 45 and the cleaning water M. (Hereinafter, the stirring unit 46 may also be simply referred to as a weir 46.) The stirring unit 46 includes a first weir 47 and a second weir 48, and agitates between the first weir 47 and the second weir 48. A region 49 is provided (enlarged view of FIG. 2).

The first weir 47 is vertically provided on the upstream side of the exhaust gas H from the ceiling portion 41a of the water tank 41, and the lower end portion thereof is submerged in the cleaning water M. Then, a passage hole to be the exhaust gas passage 47a is formed in the submerged portion. (The exhaust gas passage 47a is not limited to a hole, but may be a weir through which the exhaust gas H can dive. Here, a passage hole is used as the exhaust gas passage 47a.) The exhaust gas passage 47a is a water surface. It is formed by a slit-like gap that extends horizontally directly below the water surface or one or a plurality of through holes that are horizontally arranged. A guide nozzle 47b extending downstream is provided at the edge of the exhaust gas passage 47a.

The second weir 48 is provided on the downstream side of the first weir 47 via the stirring region 49. The installation form is such that the lower part is gradually separated from the upper part of the second weir 48 with respect to the first weir 47, and the whole is inclined downward toward the downstream side.
The upper part of the second weir 48 projects from the water surface, and the remaining lower part is submerged in the water. The upper end of the protruding portion is bent or curved in the direction of the first weir 47, and the lower end of the submerged portion is formed so as to be bent or curved obliquely downward toward the first weir 47 in the direction of the bottom 41b of the water tank 41. .. The upper bent portion is referred to as an upper bent piece portion 48b, and the lower bent portion is referred to as a lower bent piece portion 48a. As a whole, the second weir 48 has an inverted C shape.
The bending line 48l of the lower bending piece portion 48a that is submerged in the water is located below the exhaust gas passage 47a of the first weir 47.

The agitation region 49 is the space between the first weir 47 and the second weir 48 as described above, and the space between them is widest in the vicinity of the outlet portion of the exhaust gas passage 47a and becomes gradually narrower toward the top. .. The space between the tip of the upper bent piece 48b and the first weir 47 is the narrowest, and the space is connected to the flow space 45 from here.
The weir 46 is provided in the water tank 41 over the entire width in a direction perpendicular to the longitudinal direction of the water tank 41. The agitation unit 46 may be provided at one place, or two or more may be provided side by side.

An injection nozzle 50 is installed in the flow space 45 of the water tank 41 so as to eject the water M in the horizontal direction. In the illustrated embodiment, three injection nozzles 50 are installed, are connected to the branch pipe of the first pumping pipe 42, and water M for cleaning the water tank 41 is connected by the injection pump FP provided in the branch pipe. Is being supplied.

In the exhaust gas introducing nozzle portion 20, the water spray of the triple pipe 20a causes the hydrolyzable component in the exhaust gas H to react with the water M, thereby generating a large amount of dust.
In the exhaust gas cleaning unit 40, a function of collecting the dust before the exhaust gas H is sent to the thermal decomposition process of the next process, and a large amount of dust in the sent exhaust gas H adheres to and accumulates on the inner surface of the water tank 41 to accumulate in the water tank 41. It is tasked to prevent the internal flow space 45 from being blocked.
In the illustrated embodiment, since the weirs 46 are provided at a plurality of locations (three locations), the first injection nozzle 50a is located at the uppermost stream of the flow space 45 at the side wall of the water tank 41 at the downstream side of the flow space 45. The water M is jetted toward it and sprays the inner surface of the water tank 41 around this area (introduction opening 41c).
Since the area around the introduction opening 41c has the largest amount of dust, the second injection nozzle 50b is also installed on the downstream side of the introduction opening 41c in the flow space 45. The second injection nozzle 50b is arranged so as to eject in two directions, the upstream side and the downstream side of the flow space 45, and the inner surface of the water tank 41 around this is sprayed on the downstream side of the introduction opening 41c.
The third injection nozzle 50c is arranged so as to eject in two directions, that is, the upstream and downstream sides, on the downstream side of the most downstream stirring section 46, and sprays the inner surface of the water tank 41 around this.
In the above case, the injection nozzles 50 may be provided at a plurality of positions as shown in the figure, but may be provided only at the introduction opening 41c of the exhaust gas H.

In the water tank 41, in the downstream portion of the flow space 45, a separation dam plate 55 that divides the thermal decomposition tower 60 side and the outlet scrubber 80 side between the thermal decomposition tower 60 and the outlet scrubber 80 described later is provided in the water tank 41. It is provided over the entire width. The separation barrier plate 55 is hung from the ceiling portion 41a of the water tank 41, and the lower end portion thereof is submerged in the cleaning water M. As a result, the exhaust gas H flowing through the flow space 45 is blocked by the separation barrier plate 55 and guided to the thermal decomposition tower 60. The configuration downstream of the separation barrier plate 55 will be described in the section of the outlet scrubber 80.

A pyrolysis tower 60 of this embodiment shown in FIG. 5 is a pyrolysis treatment apparatus for exhaust gas H using atmospheric pressure plasma, and is a thick cylindrical tower body 62, which is installed on the top of the tower body 62. A non-transfer type plasma jet torch 61 for generating a high temperature plasma jet J toward the inside of 62, a thin cylindrical combustion cylinder portion 64 standing upright therebelow, and an upper end outer periphery of the tower body 62 are surrounded. In the ring-shaped space installed in, the water M is constantly supplied, and the water M is configured to flow water to the inner wall of the tower main body 62 by overflow to form a water film. The water M of the water tank 41 is supplied to the water introduction part 63 by the second pumping pump YP2 installed in the second pumping pipe 43.

The thermal decomposition tower 60 is erected on the upstream side of the separation barrier 55 in the downstream portion of the flow space 45 of the water tank 41, opens to the flow space 45, and has a communication opening provided in the ceiling portion 41 a of the water tank 41. It is connected to the flow-through space 45 via 41d.

The combustion cylinder portion 64 is arranged so as to coincide with the central axis of the tower body 62, and the lower end portion thereof is immersed in the water M in the water tank 41. Then, an exhaust pipe 66 is horizontally branched from a lower portion of the combustion cylinder portion 64 immediately above the water surface, penetrates the separation dam plate 55, and opens toward the outlet scrubber 80 side. The space on the outlet scrubber 80 side where the exhaust pipe 66 is opened is used as the decomposed exhaust gas inflow space 45a.

A plasma jet torch 61 provided at the top of the thermal decomposition tower 60 has a plasma generation chamber (not shown) inside, and a plasma jet J generated in the plasma generation chamber is formed in the center of the lower surface of the plasma jet torch 61. A plasma jet ejection hole (not shown) for ejecting is provided. A working gas feed pipe (not shown) such as nitrogen gas is provided on the upper side surface of the plasma jet torch 61 as needed.
The plasma jet J ejected from the plasma jet ejection hole is blown into the combustion cylinder portion 64 provided in the center of the tower body 62.

An overflow weir 56 is installed on the side of the decomposition exhaust gas inflow space 45a of the water tank 41 beyond the separation weir plate 55, the overflow weir 56 rising from the bottom 41b of the water tank 41 and having its upper end aligned with the water surface of the cleaning water M. A portion beyond the weir 56 is a drainage area 57, which is discharged as factory drainage.
The water M is supplied with the same amount of new water M as the water M discharged by the overflow, and the water M in the water tank 41 maintains a constant water level.

The outlet scrubber 80 is a so-called wet type scrubber, and its structure will be described below (FIG. 6). The outlet scrubber 80 is installed upright on the ceiling 41 a of the water tank 41 side by side with the pyrolysis tower 60.
The outlet scrubber 80 includes an outer casing 81, a cyclone cylinder portion 82, an exhaust fan 89, and its associated equipment. The auxiliary equipment includes the third pumping pipe 44 and the third pumping pump YP3 provided in the middle thereof, the first outlet cleaning spray 88a, the second outlet cleaning spray 88b, and the like.

The outer casing 81 has a hollow right circular tube shape with an opening on the lower surface, and the bottom thereof is immersed in the water M stored on the side of the decomposition exhaust gas inflow space 45a. The bottom portion immersed in the water M is provided with a plurality of decomposed exhaust gas passage holes 81a at positions immediately below the water surface. At the edge of the decomposed exhaust gas passage hole 81a, a lateral funnel-shaped guide nozzle 81b is installed facing inward. Further, a cleaning exhaust gas discharge tubular portion 86 is vertically provided so as to extend downward through the ceiling portion of the outer casing 81. The cleaning exhaust gas discharge tube portion 86 is connected to an exhaust fan 89 described later.

In the outer casing 81, a cyclone cylinder portion 82 is vertically provided at the center of the outer casing 81 from a ceiling portion of the outer casing 81. The upper portion of the cyclone cylinder portion 82 is formed in a cylindrical shape, and the cleaning exhaust gas discharge cylinder portion 86 is located at the center of the cylindrical portion 82c. A decomposed exhaust gas inlet port 82b through which the decomposed exhaust gas H flows into the cyclone cylinder portion 82 is formed in the cylindrical portion 82c. A funnel-shaped portion 82a squeezed into a funnel shape is provided downward at the lower end of the cylindrical portion 82c, and a thin tube portion 82d is provided downward from the lower end of the funnel-shaped portion 82a. The lower end portion of the thin tube portion 82d is immersed in the cleaning water M in the decomposed exhaust gas inflow space 45a.

In the space between the outer casing 81 and the thin tube portion 82d of the cyclone tube portion 82, a baffle tube member 83 is erected so as to surround the entire lower circumference of the thin tube portion 82d. The upper part of the baffle cylinder member 83 projects upward from the water M, and the lower part is immersed in the water M. The lower end portion 83a of the lower portion immersed in the water M is bent obliquely downward toward the guide nozzle 81b side, and the upper end portion 83b of the upper portion protruding upward from the water M is bent horizontally toward the thin tube portion 82d. ing. The submerged portion of the baffle cylinder member 83 faces the guide nozzle 81b of the outer casing 81, and the whole is arranged so as to be inclined with respect to the outer casing 81 as described above, and the second weir 48 of the water tank 41 is provided. Play a similar role. The bent line 83l in the submerged portion is provided below the decomposed exhaust gas passage hole 81a.

A ring-shaped baffle plate 84 is horizontally provided above the baffle cylinder member 83 from the inner peripheral surface of the outer casing 81 toward the inner side. At the edge of the hole of the ring-shaped baffle plate 84, a cylindrical portion 84a extending downward is provided. The thin tube portion 82d of the cyclone cylinder portion 82 penetrates through the center of the cylindrical portion 84a. The cylindrical portion 84a enters between the water surface projecting portion of the upper half of the baffle tubular member 83 and the thin tube portion 82d of the cyclone tubular portion 82 to form a complicated flow path for the decomposed exhaust gas H.

A plurality of first outlet cleaning sprays 88a are installed above the ring-shaped baffle plate 84 around the narrow tube portion 82d, and water is sprayed vertically in the vertical direction. A third pumping pipe 44 for pumping the water M stored on the decomposed exhaust gas inflow space 45a side is connected to the first outlet cleaning spray 88a, and a third pumping pump YP3 is provided in the middle of the third pumping pipe 44. It is provided. The sprinkling water M from the first outlet cleaning spray 88a covers the space between the cyclone cylinder portion 82 and the exterior casing 81, and the inner surfaces of both are constantly wet with the water M. The water M sprayed by the first outlet cleaning spray 88a flows down the inner surfaces of both of them and returns to the water tank 41.

A second outlet cleaning spray 88b is installed in the cleaning exhaust gas discharge cylinder portion 86, and water is sprayed from the cleaning exhaust gas discharge cylinder portion 86 toward the funnel-shaped portion 82a. The sprinkling M of the second outlet cleaning spray 88b is the final stage of water washing, and the clean exhaust gas H is released to the atmosphere, so fresh water is used.

An exhaust fan 89 is installed on the top of the outer casing 81, and is connected to the cleaning exhaust gas discharge tubular portion 86 of the outer casing 81. An exhaust pipe 89a for exhausting air, which is installed in the exhaust fan 89, is drawn out from the housing 90 and connected to the factory pipe 150.

The control panel C of the exhaust gas abatement unit U mainly includes a control system of the thermal decomposition tower 60 and a pump centralized control system that centrally controls the mechanical booster pump 2 and the roughing pump 4. The control panel C is assembled in the housing 90.

Next, the operation of the exhaust gas detoxification unit U of the present invention will be described. In the semiconductor manufacturing process, various source gases are supplied to the process chamber 201 of the semiconductor manufacturing apparatus 200, and various electronic devices (not shown) including a large number of semiconductor substrates housed in the process chamber 201 are used. Processing is performed. The raw material gas used in the reaction process becomes exhaust gas H and is discharged to the exhaust gas abatement unit U via the first foreline pipe P1. When the exhaust fan 89 is operated, the exhaust gas passage of the exhaust gas abatement unit U is maintained at a negative pressure, and the exhaust gas H is sucked by the exhaust fan 89.

Contaminant components such as reaction product components including dust generated in the above process and unreacted components are mixed in the exhaust gas H discharged. While passing through the pipes and equipment below the first foreline pipe P1, the contaminants adhere to and deposit inside the pipes. This is referred to as an inner surface deposit S. The accumulation of the adhered substances S on the inner surface becomes remarkable in the first foreline pipe P1 and below, and further downstream.

Then, the exhaust gas H sucked from the process chamber 201 by the vacuum pump 1 reaches the exhaust gas introducing nozzle portion 20 and is ejected from the exhaust gas nozzle 21 toward the exhaust gas H introducing opening 41c of the water tank 41. The protective gas curtain Gk jetted from the protective gas nozzle 25 surrounds the entire circumference of the jetted exhaust gas H.

Moisture (high temperature steam) M for hydrolysis so as to surround the inner periphery of the protective gas curtain Gk from the tip opening of the moisture ejection passage T2 of the outermost layer moisture ejection nozzle 27, and in parallel with the protective gas curtain Gk. Erupts. Since the moisture ejection passage T2 and the protective gas ejection passage T1 for forming the protective gas curtain Gk are parallel to each other, the hydrolysis moisture M ejected from the moisture ejection passage T2 to a position separated from the protective gas nozzle 25 by a certain distance is protected. It jets out in parallel with the gas curtain Gk, and within the distance range, it does not break through the protective gas curtain Gk and come into contact with the exhaust gas H inside.

When the water M is jetted from the water jet passage T2 in parallel with the protective gas curtain Gk as described above, the water M spreads at a certain distance as the flow velocity decreases, and the water M, the protective gas curtain Gk, and the exhaust gas H are released. Mix together. The dish-shaped portion 31 of the scattering member 30 is installed at this point, and the exhaust gas H, the protective gas curtain Gk, and the moisture M collide with each other. Then, due to this collision, they are scattered around the dish-shaped portion 31 and rise up in the casing 35. During this period, the gas-liquid contact between the exhaust gas H and the water M is effectively performed, and the hydrolyzable component in the exhaust gas H contacts the water M to generate a large amount of dust.

The dust tends to adhere to the inner surface of the casing 35 and the triple pipe 20a, but is constantly washed off by the water M flowing in the casing 35, and the adhesion to the inner surface of the casing 35 and the triple pipe 20a is alleviated.

On the other hand, in the upper part of the casing 35 that has soared in the casing 35, the protective gas curtain Gk is vigorously ejected from the protective gas nozzle 25, so that the soared water M does not break through the protective gas curtain Gk and the protective gas curtain Gk. Within the protection range of 1, there is no contact with the discharged exhaust gas H. Therefore, there is no reverse osmosis of the water M traveling up the third foreline pipe P3.

The exhaust gas H blown into the flow space 45 of the water tank 41 together with a large amount of dust comes into contact with the jet water M from the first and second injection nozzles 50a and 50b which covers the entire surface of the introduction opening 41c of the exhaust gas H and a part thereof. Are collected and collected in the water M in the water tank 41. At the same time, the sprayed water M wets the inner wall of the water tank 41 to wash away the inner surface deposit S that tends to adhere to the inner wall and delay the deposition.

The exhaust gas H is sucked by the exhaust fan 89, and the exhaust gas H flows toward the stirring section 46 together with the dust that has not been collected due to the air flow toward the thermal decomposition tower 60. It is necessary to prevent this dust from being brought into the subsequent thermal decomposition step as much as possible.
In the stirring unit 46, the exhaust gas H collides with the first weir 47, suppresses the water surface in the vicinity of the first weir 47 by its force, passes through the exhaust gas passage 47a immediately below the water surface, and enters the stirring region 49. In the stirring area 49, bubbles are floated while being stirred, and during that time, the water M and the exhaust gas H come into gas-liquid contact with each other, and foreign substances such as dust in the exhaust gas H are effectively collected in the water M. Since the lower bent piece 48a of the second weir 48 is curved downward in the direction of the first weir 47, the water M spouted along the second weir 48 due to the floating of the bubbles causes the upper bent piece of the projecting portion to rise. It abuts against 48b and is returned downward to sufficiently stir the stirring area 49. This enhances the dust collection effect.
The bubble-like exhaust gas H floats as it is, pops off on the water surface, and enters the flow space 45.

When the agitating unit 46 is provided in a plurality of stages, the above-described collecting action is repeated, and by the time it reaches the thermal decomposition tower 60, the cleaning exhaust gas H contains almost no impurities such as dust.

From the above, in the exhaust gas path from the first foreline pipe P1 to the exhaust gas nozzle 21 of the exhaust gas introduction nozzle unit 20, the protective gas curtain Gk of the exhaust gas introduction nozzle unit 20 causes the water content M in the exhaust gas introduction nozzle unit 20 to be hydrolyzable. The contact with the exhaust gas H containing the components is blocked, and the clogging of the above path is suppressed. Then, in the casing 35 of the exhaust gas introducing nozzle portion 20, most of the hydrolyzable components in the exhaust gas H are decomposed by gas-liquid contact between the exhaust gas H and the scattered water (high temperature steam) M due to the presence of the scattering member 30, It is accompanied by a large amount of dust.
Then, the exhaust gas H accompanied by the dust is washed in multiple stages in the stirring section 46 of the water tank 41 and is supplied to the thermal decomposition tower 60 in a state without the dust.

The exhaust gas H washed in the water tank 41 is introduced into the thermal decomposition tower 60 through the communication opening 41d of the water tank 41, and the plasma jet J of the plasma jet torch 61 is introduced in the thermal decomposition region 65 above the tower body 62 and the combustion cylinder 64. To be pyrolyzed in the presence of moisture. As a result, dust such as dust and reaction products are generated in the decomposed exhaust gas H.
The thermally decomposed exhaust gas H passes through the combustion cylinder portion 64 together with impurities. Since the lower end of the combustion tube portion 64 is open, most of the impurities such as dust and reaction products contained in the decomposed exhaust gas H fall as they are and fall into the water M of the water tank 41 to be collected. The decomposed exhaust gas H flows into the decomposed exhaust gas inflow space 45a together with the remaining lightweight impurities through the exhaust pipe 66.

The decomposed exhaust gas H that has flowed into the decomposed exhaust gas inflow space 45a pushes down the water surface in the vicinity of the decomposed exhaust gas passage hole 81a of the outer casing 81 by the suction force of the exhaust fan 89, flows into the decomposed exhaust gas passage hole 81a, and interferes with the outer casing 81. In the stirring area 87 between the tubular member 83 and the tubular member 83, bubbles rise and rise. The water M in the stirring area 87 is largely stirred by this foaming. As a result, most of the impurities including dust contained in the decomposed exhaust gas H are collected by the water M in the stirring area 87.

The cleaned decomposed exhaust gas H passes through a meandering flow path between the baffle cylinder member 83 and the ring-shaped baffle plate 84, and from the space between the cylindrical portion 84a of the ring-shaped baffle plate 84 and the thin tube portion 82d to the ring. Appear in the space above the baffle plate 84. In the meandering flow path, the cleaned decomposed exhaust gas H becomes a turbulent flow and comes into contact with the baffle cylinder member 83, the ring-shaped baffle plate 84, and the narrow tube portion 82d. A first outlet cleaning spray 88a is installed above the ring-shaped baffle plate 84, and the sprinkled water M from this sprays out the attached contaminants.
Since the first outlet cleaning spray 88a sprinkles water M in the upper and lower directions, the inner surface of the outer casing 81 is covered with the falling water film, so that the foreign matters are washed away and do not adhere.

The decomposed exhaust gas H is not collected even by the showering, rises together with a slight amount of impurities and mist that did not fall, and enters the cyclone cylinder portion 82 through the decomposed exhaust gas inlet port 82b. The decomposed exhaust gas H that has entered the cyclone cylinder 82 swirls around the cleaning exhaust gas discharge cylinder 86, and due to the formation of vortices in the cyclone cylinder 82, impurities and mists heavier than the decomposed exhaust gas H are generated by the centrifugal force and gravity. It falls while rotating and is collected in the water M in the water tank 41.
The clean exhaust gas H containing no contaminants after being washed with water and a cyclone is sucked by the exhaust fan 89, discharged to the exhaust pipe 89a, and flows to the factory pipe 150.

When the reaction process and its detoxification work are completed, the process chamber 201 is switched to the cleaning process. In the cleaning process, the common pipe 17 of the inner surface cleaning unit 16 is connected to the connector P2c of the second foreline pipe P2. At this stage, the open/close valves 18v and 19v are closed.
After that, a fluorine-based cleaning gas (for example, C ₂ F ₆ , NF ₃ etc.) is flown into the process chamber 201 to change the reaction product attached to the inner surface of the process chamber 201 into a volatile gas such as NF _4. Flow to the exhaust gas abatement unit U side. As a result, the inside of the process chamber 201 is cleaned.

On the exhaust gas removal unit U side, dust and reaction products are attached to the exhaust gas path from the first foreline pipe P1 to the exhaust gas introduction nozzle portion 20. In the cleaning process, the cleaning gas is supplied to the process chamber 201, but most of the cleaning gas is consumed in the cleaning process of the process chamber 201, and the exhaust gas after cleaning which is sucked into the first foreline pipe P1 has the first foreground. There is almost no cleaning capability in the exhaust gas passage below the line pipe P1.

Therefore, the opening/closing valve 10a is opened, and a cleaning gas (for example, NF ₃ ) is separately supplied to the inner surface cleaning unit 10 to clean the inner surface of the exhaust gas passage below the first foreline pipe P1.
That is, the high-frequency power source 14 is operated and a high-frequency voltage is applied to the high-frequency coil 13 while separately supplying the cleaning gas to the radical generation chamber 12 of the inner surface cleaning unit 10. Then, capacitively coupled plasma (CCP) is generated inside the loop portion 13a of the high frequency coil 13, and an inductively coupled plasma (ICP) is generated by flowing an induction current due to an induction magnetic field in the CCP.

The cleaning gas is decomposed by high heat of the ICP in the radical generation chamber 12 and electron impact. As a result, a large amount of fluorine radicals F· are generated, and reaction products S attached to the inner surfaces of the first foreline pipe P1 and the mechanical booster pump 2 as well as the equipment and pipes downstream thereof are generated while passing through them. Gasify. That is, the F radical F· generated by decomposing NF ₃ gasifies and cleans the reaction product S by the reaction of Si+4F→SiF ₄ . As a result, the inner surface of the first foreline pipe P1, the mechanical booster pump 2, and the equipment and pipes downstream thereof are simultaneously cleaned during the cleaning process of the process chamber 201.

When the inner surface cleaning with the fluorine radicals F. is completed, the on-off valve 10a of the inner surface cleaning unit 10 is closed.
The common pipe 17 of the inner surface cleaning unit 16 is connected to the connector P2c at the lower end of the second foreline pipe P2 prior to the inner surface cleaning. After closing the opening/closing valve 10a of the inner surface cleaning unit 10, the opening/closing valve 18v of the water supply pipe 18 of the inner surface cleaning unit 16 is opened.
The cleaning water M discharged from the water supply pipe 18 flows into the roughing pump 4 through the common pipe 17, enters the third foreline pipe P3 through the roughing pump 4, and then passes through the exhaust gas nozzle 21. It flows into the water tank 41. As a result, the equipment below the roughing pump 4 and the inside of the third foreline pipe P3 are cleaned. Since water cannot be passed through the mechanical booster pump 2, water cleaning is performed by the roughing pump 4 and below.

When the water washing is completed, the opening/closing valve 18v of the water supply pipe 18 is closed and the opening/closing valve 19v of the dry gas supply pipe 19 is opened. As a result, the heated inert gas (for example, heated nitrogen gas) G is supplied from the dry gas supply pipe 19, flows into the water tank 41 through the water washing path, and dries the inner surface of the path. Cleaning of the exhaust system is completed by this drying, and the process goes to the next manufacturing process.

As described above, in the present invention, the exhaust gas introducing nozzle unit 20 and the exhaust gas cleaning unit 40 cooperate with each other to decompose the hydrolyzable components contained in the exhaust gas H and to eliminate impurities such as dust due to this decomposition. Not only that, the cooperation of the inner surface cleaning unit 10 and the inner surface cleaning unit 16 can clean the exhaust gas path from the first foreline pipe P1 to the exhaust gas introduction nozzle unit 20 in accordance with the cleaning process, and the most clogging accident occurs. It is now possible to greatly reduce the clogging of this part.

C: control panel, F・: fluorine radical, FP: injection pump, G: protective gas (dry gas/heating gas/inert gas), Gk: protective gas curtain, H: exhaust gas, J: plasma jet, M: moisture (Water, water droplets, mist, steam, jet water, water spray), P1: first foreline pipe, P2: second foreline pipe, P2c: connector, P3: third foreline pipe, S: inner surface deposit (reaction) Product), T1: Protective gas jet, T2: Moisture jet, U: Exhaust gas removal unit, YP1: First pump, YP2: Second pump, YP3: Third pump 1: Vacuum pump, 2 : Mechanical booster pump, 4: Roughing pump, 10: Internal cleaning part, 10a: Open/close valve, 12: Radical generation chamber, 12a: Inlet opening, 12b: Outlet opening, 12c: Decomposition gas supply pipe, 13: High frequency Coil, 13a: loop part, 14: high frequency power supply, 16: inner surface cleaning part, 17: common pipe, 18: water supply pipe, 18v: open/close valve, 19: dry gas supply pipe, 19v: open/close valve, 20: exhaust gas introduction nozzle Part, 20a: triple pipe, 21: exhaust gas nozzle, 21f: exhaust gas nozzle, 25: protective gas nozzle, 25a: nozzle hole, 25b: storage recess, 25c: nozzle part, 25f: protective gas nozzle, 26: protective gas Supply pipe, 26a: Gas reservoir, 27: Moisture ejection nozzle, 27c: Nozzle part, 28: Moisture supply pipe, 28a: Water reservoir, 30: Scattering member, 31: Plate-shaped part, 31a: Collision part, 31b: Raised edge, 32: leg part, 33: exhaust gas downflow hole, 34: support member, 35: casing, 40: exhaust gas cleaning part, 41: water tank, 41a: ceiling part, 41b: bottom part, 41c: introduction opening, 41d: communication opening, 42 : First pumping pipe, 43: second pumping pipe, 44: third pumping pipe, 45: flow space, 45a: decomposition exhaust gas inflow space, 46: stirring section (weir), 47: first weir, 47a: exhaust gas Passage path, 47b: guide nozzle, 48: second weir, 48a: lower bending piece portion, 48b: upper bending piece portion, 48l: bending line, 49: stirring area, 50 (50a to 50c): injection nozzle, 55: Separation weir plate, 56: overflow weir, 57: drainage region, 60: thermal decomposition tower, 61: plasma jet torch, 62: tower body, 63: water introduction part, 64: combustion cylinder part, 65: thermal decomposition region, 66 : Exhaust pipe, 80: Outlet scrubber, 81: Exterior casing, 81a: Decomposition exhaust gas passage hole, 81b: Guide nozzle, 82: Cyclone cylinder part, 82a: Funnel shape Part 82b: Decomposed exhaust gas introduction port, 82c: Cylindrical part, 82d: Thin tube part, 83: Baffle cylinder member, 83a: Lower end part, 83b: Upper end part, 83l: Bending line, 84: Ring-shaped baffle plate, 84a: Cylindrical part, 86: Cleaning exhaust gas discharge cylinder part, 87: Agitation region, 88a: First outlet cleaning spray, 88b: Second outlet cleaning spray, 89: Exhaust fan, 89a: Exhaust pipe, 90: Housing, 91 : Shelf, 150: Factory piping, 200: Semiconductor manufacturing equipment, 201: Process chamber, 210: Clean room, 220: Floor.

Claims (2)

Included in a vacuum pump that sucks exhaust gas from a process chamber of a semiconductor manufacturing apparatus, an exhaust gas introduction nozzle section that cleans the exhaust gas discharged from the vacuum pump with water, and a cleaning exhaust gas that has been washed with water and discharged from the exhaust gas introduction nozzle section In an exhaust gas abatement unit including an exhaust gas cleaning unit that collects contaminants to be collected and sends the cleaning exhaust gas to the next exhaust gas decomposition step,
The vacuum pump is a mechanical booster pump connected to a first foreline pipe drawn from the process chamber of the semiconductor manufacturing apparatus, and a second foreline installed below the mechanical booster pump and drawn from the mechanical booster pump. It consists of a roughing pump connected to piping,
An exhaust gas introducing nozzle part is connected to the third foreline pipe drawn out from the roughing pump,
An inner surface deposit of a constituent member that is connected to the first foreline pipe and supplies fluorine radicals into the first foreline pipe during cleaning of the semiconductor manufacturing apparatus to form the first foreline pipe and the following constituent members including the exhaust gas introducing nozzle portion. An inner surface cleaning section for removing
The second foreline pipe is connected to the second foreline pipe, and water for cleaning is supplied after cleaning the inner face with fluorine radicals to wash the adhering substances on the inner face of the constituent member including the exhaust gas introducing nozzle portion below the second foreline pipe with water. Then, after that, a dry gas is supplied to the second foreline pipe, and an inner surface cleaning section for drying the inner surface of the constituent member including the exhaust gas introduction nozzle section is formed. Harm unit. A vacuum pump, an exhaust gas introduction nozzle part, an exhaust gas cleaning part, and a pyrolysis tower for thermally decomposing the cleaning exhaust gas from the exhaust gas cleaning part, and decomposition exhaust gas produced by the thermal decomposition by washing the decomposition exhaust gas from the thermal decomposition tower with water. An outlet scrubber that removes impurities inside and discharges decomposed exhaust gas as clean exhaust gas to the outside of the apparatus, a piping system that connects the constituent devices, and a housing that houses these. The exhaust gas abatement unit according to 1.