JP5368003B2 - Filtration type dust collector and exhaust gas abatement system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filtration type dust collector capable of efficiently removing dust and hydrogen fluoride, etc., incorporated in waste gas which is discharged from a semiconductor manufacturing device and then heat-treated, and reacting slaked lime to be used for the reaction with the hydrogen fluoride or the like laconically. <P>SOLUTION: The filtration type dust collector 14 includes: a body part 20 for receiving the waste gas F from a waste gas heating device 12, executing dry treatment of the waste gas F and then deriving it to an exhaust fan 16; and a circulation part 22 for circulating a part of the waste gas F after filtered by a filter 28 from the upper space 24c of a casing 24 to hte lower space 24d as circulating waste gas CF. In the collector, a waste gas introducing duct 46 for circulation for introducing the circulating waste gas CF to the lower space 24d of the casing 24 is connected to the bottom part 24b of the casing 24. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a filtration dust collector suitable for removing dust, hydrogen fluoride, and the like in exhaust gas discharged from a semiconductor manufacturing apparatus and subjected to heat treatment, and an exhaust gas abatement apparatus using the same.

  In manufacturing processes for semiconductors and liquid crystals (hereinafter referred to as “semiconductor manufacturing processes”), various types of fluorine compounds are used. Many of these fluorine compounds have a great impact on human health and the global environment. It is known to give. For this reason, the used fluorine compound is appropriately detoxified by various methods in the exhaust gas abatement apparatus.

  As such an exhaust gas abatement apparatus, for example, as shown in FIG. 7, after removing dust and the like contained in the exhaust gas F discharged from the semiconductor manufacturing apparatus A by the inlet scrubber B, the exhaust gas heating provided with an electric heater or the like There is known an exhaust gas abatement apparatus that heat-treats the exhaust gas F in the apparatus C and detoxifies the heat-treated exhaust gas F by gas-liquid contact with a wet outlet scrubber D.

  If this exhaust gas abatement apparatus is used, the fluorine compound in the exhaust gas F becomes hydrogen fluoride (HF) by thermal decomposition. The hydrogen fluoride becomes hydrofluoric acid when it comes into gas-liquid contact with water at the outlet scrubber D, and the fluorine compound is removed from the exhaust gas by dissolving the hydrofluoric acid into the waste water. In addition, the substance that dissolves into the waste water at the outlet scrubber D of the exhaust gas abatement device is not only hydrogen fluoride, but also other hydrogen chloride (HCl) and hydrogen bromide (HBr) mixed in the exhaust gas F that has been thermally decomposed. Acid gases also dissolve as acids. Hereinafter, these are collectively referred to as “hydrogen fluoride and the like” or “hydrofluoric acid and the like”.

However, as described above, the dust [for example, silicon dioxide (SiO ₂ ) produced by oxidative decomposition of silane (SiH ₄ )] and hydrogen fluoride contained in the exhaust gas F is treated with water. In “wet treatment”, it is necessary to provide a waste water treatment device E that separately treats waste water containing dust, hydrofluoric acid, and the like, and there is a problem of increasing the equipment cost and exhaust gas treatment cost of the exhaust gas abatement device.

  In order to deal with such problems, as shown in FIG. 8, the exhaust gas F from the semiconductor manufacturing apparatus A is first heat-treated by the exhaust gas heating apparatus C, and then widely used in the exhaust gas treatment of municipal waste incinerators. A “dry process” in which dust, hydrogen fluoride, and the like in the exhaust gas F are removed with a filter-type dust collector 1 (for example, Patent Document 1) is considered.

  As shown in FIG. 9, the filter-type dust collector 1 of Patent Document 1 includes a dust collector body 3 having a filter 2 therein, an exhaust gas inlet pipe 4, an exhaust gas outlet pipe 5, an exhaust gas outlet pipe 5, and an exhaust gas inlet. An exhaust gas circulation line 6 that connects the pipes 4 to each other, a circulation fan 7 that is provided in the exhaust gas circulation line 6 and circulates the exhaust gas F from the exhaust gas outlet line 5 to the exhaust gas inlet line 4, and the exhaust gas inlet line 4 And a slaked lime introduction conduit 8 that continuously introduces slaked lime S into the exhaust gas inlet conduit 4.

After being discharged from the semiconductor manufacturing apparatus A and heated in the exhaust gas heating apparatus C, the dust contained in the exhaust gas F introduced into the exhaust gas inlet pipe 4 is filtered by the filter 2 in the dust collector main body 3. When passing through, it is filtered from the exhaust gas F. Further, the hydrogen fluoride contained in the exhaust gas F reacts with the slaked lime S introduced into the exhaust gas inlet pipe 4 via the slaked lime introduction pipe 8, mainly in the dust collector main body 3 and the inner surface of the filter 2. Solid calcium fluoride (CaF ₂ ) [hydrogen chloride in exhaust gas F becomes calcium chloride (CaCl ₂ ), and hydrogen bromide becomes calcium bromide (CaBr ₂ ). Hereinafter, these are collectively referred to as “calcium fluoride and the like”. ], The exhaust gas F is filtered by the filter 2 in the same manner as dust.

  As described above, since the exhaust gas F from the semiconductor manufacturing apparatus A is dry-processed by the filtration dust collector 1 instead of the inlet scrubber B and the outlet scrubber D, it is not necessary to provide the waste water treatment apparatus E. Equipment costs and exhaust gas treatment costs can be reduced.

In addition, in the filtration type dust collector 1 of Patent Document 1, by introducing a part of the exhaust gas F filtered by the dust collector body 3 into the exhaust gas inlet line 4 through the circulation fan 7 and the exhaust gas circulation line 6, The exhaust gas F once processed is processed again by the dust collector main body 3, and dust, hydrogen fluoride, and the like that have not been removed by the first process are removed by the second and subsequent processes. Thereby, the removal efficiency of dust, hydrogen fluoride, and the like contained in the exhaust gas F can be further increased.
JP-A-10-202031

  However, the filtration dust collector 1 of Patent Document 1 has the following problems. That is, when dust or calcium fluoride filtered from the exhaust gas F accumulates on the surface of the filter 2 and the pressure loss when the exhaust gas F passes through the filter increases, the accumulated dust or calcium fluoride is removed from the surface of the filter. Is removed by a removal device (not shown) and discharged to the outside by a conveyor 9 attached to the lower part of the dust collector main body 3. Among those discharged to the outside in this way are hydrogen fluoride A considerable amount of slaked lime S that does not react with the slaked lime S is included, and there is a problem that the utilization efficiency of the slaked lime S is poor.

  In particular, as described above, when a part of the exhaust gas F processed by the dust collector main body 3 is circulated to the inlet of the dust collector main body 3, the concentration of hydrogen fluoride or the like in the exhaust gas F processed by the dust collector main body 3 is increased. Since it becomes low, the probability that hydrogen fluoride etc. will contact slaked lime S also becomes low, the ratio of the slaked lime S discharged | emitted from a dust collector main body without being able to contact hydrogen fluoride etc. becomes higher, and the utilization efficiency of slaked lime S is improved. There was a problem of getting worse.

  In addition, in semiconductor manufacturing processes, the concentration of airborne dust and the like is strictly regulated, and semiconductor manufacturing equipment and exhaust gas abatement equipment are generally installed in a clean room with a predetermined air cleanliness. Is. For this reason, as in the filter-type dust collector 1 of Patent Document 1 (for exhaust gas treatment of municipal waste incinerators), new slaked lime S is continuously introduced from the slaked lime introduction conduit 8 and the dust filtered through the filter 2 Since the method of continuously discharging calcium fluoride or the like causes an increase in the dust concentration in the clean room, the filter-type dust collector 1 of Patent Document 1 is employed as it is in an exhaust gas abatement device for a semiconductor manufacturing apparatus. In order to use such a filter-type dust collector in a semiconductor manufacturing process, a new slaked lime S is previously stored in the filter-type dust collector, and the slaked lime S previously stored without introducing new slaked lime S is used. The filter-type dust collector is operated until it is used up, and after the slaked lime S is used up, the filter-type dust collector is stopped and the filtered dust, calcium fluoride, etc. are taken out and new slaked lime S is again used. It forced a "batch" process, such as houses.

  In this “batch type” process, the continuous operation time of the filtration dust collector is made as long as possible, so that the stop time of the filtration dust collector can be relatively shortened, leading to an improvement in overall operation efficiency. Therefore, the importance of improving the utilization efficiency of slaked lime S in the filtration dust collector used in the exhaust gas abatement apparatus for semiconductor manufacturing equipment is not comparable to the importance in the filtration dust collector used for other applications. Big.

  The present invention has been developed in view of such problems of the prior art. Therefore, the main object of the present invention is to remove dust and hydrogen fluoride contained in the heat-treated exhaust gas after being discharged from the semiconductor manufacturing apparatus, and to be used for reaction with hydrogen fluoride or the like. Another object of the present invention is to provide a filtration dust collector capable of reacting slaked lime without waste and an exhaust gas abatement apparatus using the same.

The invention described in claim 1
“(A) casing 24 having internal space 24a,
The internal space 24a of the casing 24 is partitioned into an upper space 24c and a lower space 24d into which the exhaust gas F and the powdered slaked lime S discharged from the semiconductor manufacturing apparatus A and heated are introduced, and the lower space 24d And a partition member 26 having a communication hole 40 communicating with the upper space 24c.
A filter 28 that is attached to the communication hole 40 and filters the exhaust gas F guided from the lower space 24d to the upper space 24c through the communication hole 40;
One end is connected to the portion of the casing 24 facing the lower space 24d, the exhaust gas introduction duct 30 for introducing the exhaust gas F into the lower space 24d, and one end is connected to the portion of the casing 24 facing the upper space 24c. A main body 20 including an exhaust gas outlet duct 32 that guides the exhaust gas F after being filtered by the filter 28 from the upper space 24c;
(B) a circulation fan 42 for circulating a part of the exhaust gas F after being filtered by the filter 28 from the upper space 24c to the lower space 24d;
One end of the casing 24 is connected to the portion facing the upper space 24c, the other end is connected to the circulation fan 42, and one end is connected to the circulation fan 42. The other end is connected to the circulation fan 42. A batch type filtration dust collector 14 including a circulation unit 22 including a circulation exhaust gas introduction duct 46 connected to the bottom 24b of the casing 24 facing the lower space 24d ,
The other end side of the circulation exhaust gas introduction duct 46 is branched into a plurality and connected to the bottom 24b of the casing 24,
Each of the circulation exhaust gas introduction ducts 46 branched into a plurality is provided with a flow rate adjusting means 50 for adjusting the flow rate of the exhaust gas to be circulated (circulation exhaust gas CF).
The flow rate adjusting means 50 repeats full-close and full-open alternately every predetermined time according to an instruction from a timer to generate a turbulent flow in the lower space 24d of the casing 24. A dust collector 14.

  In the filtration type dust collector 14 according to the present invention, the exhaust gas introduction duct 46 for circulation is connected to the bottom 24b of the casing 24 facing the lower space 24d, and a part of the exhaust gas F after being filtered by the filter 28 is a circulation fan. 42 is introduced into the lower space 24d from the bottom 24b of the casing 24 as the circulating exhaust gas CF through the circulating exhaust gas outlet duct 44 and the circulating exhaust gas introduction duct 46.

  For this reason, the slaked lime S in the lower space 24d is constantly stirred by the introduced circulating exhaust gas CF (of course, dust and calcium fluoride are also stirred at the same time), and thus introduced into the lower space 24d. The opportunity for the hydrogen fluoride contained in the exhaust gas F to come into contact with the slaked lime S can be dramatically increased.

Further , according to the present invention, the slaked lime S in the lower space 24d of the casing 24 is more effectively agitated by controlling the flow rate adjusting means 50 provided in the exhaust gas introduction duct 46 for circulation branched into a plurality. As described below, the chance of contact between hydrogen fluoride and slaked lime S contained in the exhaust gas F (hereinafter referred to as “circulated exhaust gas CF”) circulated in the lower space 24d can be further increased.

  That is, as shown in FIG. 1, one flow rate adjusting unit 50a is fully opened and the other flow rate adjusting unit 50b is fully closed. After a predetermined time has elapsed, on the contrary, one flow rate adjusting unit 50a is fully opened. The other flow rate adjusting means 50b is fully opened while being closed. By repeating this, the slaked lime in the vicinity of the end 46a of the one exhaust gas introduction duct for one circulation during the period in which one flow rate adjusting means 50a is fully open (FIG. 1 shows the state of this period). S, dust, calcium fluoride, etc. can be blown up with the circulating exhaust gas CF and stirred, but the other flow rate adjusting means 50b is fully closed, so that it is near the end 46b of the other circulating exhaust gas introduction duct. Is deposited with slaked lime S, dust and calcium fluoride. Then, after the predetermined time has elapsed, one flow rate adjusting means 50a is fully closed and the other flow rate adjusting means 50b is fully opened, so that the end of the other circulation exhaust gas introduction duct is reversed. The slaked lime S, dust, and calcium fluoride in the vicinity of 46b are agitated, and the slaked lime S and the like are deposited in the vicinity of the end 46a of one circulation exhaust gas introduction duct.

  In this way, by switching the position of the circulating exhaust gas CF introduced into the lower space 24d, the flow of the exhaust gas F in the lower space 24d is disturbed, thereby further increasing the stirring of the slaked lime S and Contact opportunities can be further increased.

The invention described in claim 2 relates to the filter-type dust collector 14 described in claim 1 , “The bottom 24 b of the casing 24 is composed of a plurality of mortar-shaped portions 34 narrowing downward, and is branched into a plurality. Each of the circulation exhaust gas introduction ducts 46 is connected to the bottom portions 34a, 34b of the mortar-shaped portions 34 ".

  According to the present invention, the slaked lime S and the like accumulate together on the mortar-shaped portion 34 corresponding to the flow rate adjusting means 50 during the period when one flow rate adjusting means 50 is fully closed. Since the exhaust gas introduction duct 46 for circulation is connected to the bottom portions 34a and 34b of the mortar-shaped portion 34, the slaked lime S collected and accumulated in the mortar-shaped portion 34 when the flow rate adjusting means 50 is then fully opened. Are blown away from the bottom portions 34a, 34b of the mortar-shaped portion 34 upward by the circulating exhaust gas CF. Thereby, the contact opportunity of the hydrogen fluoride and the slaked lime S in the lower space 24d of the casing 24 can be further increased.

The invention described in claim 3 relates to the filter-type dust collector 14 described in claim 1 or 2 , wherein “a removal device for applying stress to the filter 28 for removing slaked lime S and dust adhering to the filter 28”. As a result, a large amount of dust adheres to the filter 28, and the pressure loss when the exhaust gas F passes through the filter 28 becomes excessive. In the worst case, the filter 28 It can be avoided that the exhaust gas F cannot be filtered. Moreover, the pressure loss value when the exhaust gas F passes through the filter 28 can be managed by regularly removing dust.

The invention described in claim 4 is: “An exhaust gas heating device 12 that receives the exhaust gas F discharged from the semiconductor manufacturing apparatus A and heat-treats the exhaust gas F at a high temperature;
The filtration type dust collector according to any one of claims 1 to 3 , which receives the exhaust gas F discharged from the exhaust gas heating device 12.
It is an exhaust gas abatement apparatus 10 ”provided with an exhaust fan 16 that exhausts the exhaust gas F discharged from the filtration dust collector 14 to the outside.

  According to the present invention, after the exhaust gas F containing the dust and fluorine compound discharged from the semiconductor manufacturing apparatus A is heat-treated with the exhaust gas heating device 12, the fluorine compound contained in the exhaust gas F is changed to hydrogen fluoride or the like, Dust and hydrogen fluoride in the exhaust gas F can be removed by a dry process with the filtration dust collector 14. Thereby, since it is not necessary to provide a waste water treatment device, the equipment cost and the exhaust gas treatment cost of the exhaust gas abatement device can be reduced.

The invention described in claim 5 is “the exhaust gas heating device 12 that receives the exhaust gas F discharged from the semiconductor manufacturing apparatus A and heat-treats the exhaust gas F at a high temperature;
A set of filtration type dust collectors 14a, 14b according to any one of claims 1 to 3 , which are arranged in parallel with each other and receive the exhaust gas F discharged from the exhaust gas heating device 12.
An exhaust fan 16 for discharging the exhaust gas F discharged from the filtration dust collector 14 to the outside;
A flow path opening / closing means 52 provided in each of the exhaust gas introduction duct 30 and the exhaust gas discharge duct 32 of each of the filtration dust collectors 14 for opening and closing the flow paths of the exhaust gas introduction duct 30 and the exhaust gas discharge duct 32;
The exhaust gas introduction duct 30 between the one filter type dust collector 14a and the flow path opening / closing means 52 provided on the upstream side thereof, and the other filter type dust collector 14b and the above provided on the downstream side thereof. A first communication duct 54a that communicates the exhaust gas outlet duct 32 with the flow path opening / closing means 52;
The exhaust gas derivation duct 32 between one of the filter dust collectors 14a and the flow path opening / closing means 52 provided on the downstream side thereof, and the other filter dust collector 14b and the upstream of the filter dust collectors 14b provided thereon. A second communication duct 54b that communicates the exhaust gas introduction duct 30 with the flow path opening / closing means 52;
Exhaust gas abatement apparatus 10 provided with communication duct flow path opening / closing means 56 that opens and closes the flow paths of the first and second communication ducts 54a and 54b, provided in the first and second communication ducts 54a and 54b, respectively. It is.

According to the present invention, similarly to the exhaust gas abatement apparatus 10 according to claim 4 , it is not necessary to provide a waste water treatment apparatus, so that the equipment cost and the exhaust gas treatment cost of the exhaust gas abatement apparatus 10 can be reduced. it can.

  In addition, a set of filter dust collectors 14a and 14b can be connected in parallel to each other or connected in series by appropriately switching the fully closed or fully opened state of the flow path opening / closing means 52 and the communication duct flow path opening / closing means 56. Can do. As a result, when there is a large amount of exhaust gas to be dry-processed, a pair of filtration type dust collectors 14a and 14b can be connected in parallel to correspond to a large amount of exhaust gas F. If the concentration of dust, hydrogen fluoride, etc. in the exhaust gas F discharged from the exhaust fan 16 to the outside of the exhaust gas abatement device 10 needs to be extremely low, a set of filtration types The dust collectors 14a and 14b can be connected in series, and the exhaust gas F can be dealt with by continuous dry processing with the two filtration dust collectors 14a and 14b.

  Further, when a pair of filtration type dust collectors 14a and 14b are connected in series, the exhaust gas F is first passed through the "first filtration type dust collector 14a" as shown in FIG. A route (route A) for passing through the “dust collector 14b” and a route (route B) for passing through the “first filter dust collector 14a” after passing through the “second filter dust collector 14b” as shown in FIG. And the exhaust gas abatement apparatus 10 that can use the slaked lime S more efficiently can be operated.

  If it does in this way, after switching a path | route, the slaked lime S which is used with the filtration type dust collector 14 with the low density | concentration, such as hydrogen fluoride in the waste gas F introduced, will be introduced after switching a path | route. Since it will be used in the filtration type dust collector 14 having a higher concentration of hydrogen fluoride or the like in the exhaust gas F, not only can the slaked lime S be used without waste, but also hydrogen fluoride or the like in the introduced exhaust gas F. Since new slaked lime S is always used in the filtration type dust collector 14 having the lower concentration of hydrogen, the chance of hydrogen fluoride etc. coming into contact with the slaked lime S is maximized even if the concentration of hydrogen fluoride etc. is low. The slaked lime S can be used without waste, and the concentration of hydrogen fluoride or the like finally discharged from the exhaust gas abatement apparatus 10 can be minimized.

  According to the present invention, the chance of contact between slaked lime and hydrogen fluoride contained in the exhaust gas introduced into the lower space is greatly increased, and dust and hydrogen fluoride contained in the exhaust gas from the semiconductor manufacturing apparatus It is possible to provide a filtration dust collector capable of reacting slaked lime used for reaction with hydrogen fluoride and the like without waste and an exhaust gas abatement apparatus using the same.

  The present invention will be described below with reference to the illustrated embodiments. An exhaust gas abatement apparatus 10 to which the present invention is applied is an apparatus for detoxifying an exhaust gas F discharged from a semiconductor manufacturing apparatus A that manufactures semiconductors, liquid crystals, etc., and containing dust, fluorine compounds, etc. As shown in FIGS. 1 and 2, the exhaust gas heating device 12, a pair of filter-type dust collectors 14 a and 14 b connected in parallel to each other, and an exhaust fan 16 are generally included.

The exhaust gas heating device 12 receives the exhaust gas F discharged from the semiconductor manufacturing apparatus A, and heats the exhaust gas F at a high temperature in the presence of air or moisture. By heat-treating the exhaust gas F at a high temperature, for example, reactions such as the following formulas (1) and (2) are performed.
SiH ₄ + 2O ₂ → SiO ₂ (dust) + 2H ₂ O Formula (1)
2NF ₃ + 3H ₂ O → 6HF (hydrogen fluoride) + N ₂ O ₃ Formula (2)

  As a heat source for heating the exhaust gas F, an electric heater, atmospheric pressure plasma, a fuel burner, or the like can be used.

  A set of filtration type dust collectors 14a and 14b arranged in parallel with each other (of course, the number of filtration type dust collectors 14 may be one, or three or more may be used as one set). 1 is a device for receiving the exhaust gas F heat-treated in the above and dry-treating dust, hydrogen fluoride and the like contained in the exhaust gas F. As shown in FIG. 22.

  The main body 20 includes a casing 24, a partition member 26, a filter 28, an exhaust gas introduction duct 30, an exhaust gas outlet duct 32, and a dropping device 33 provided as necessary.

  The casing 24 is a box-shaped body formed of a steel plate such as stainless steel (of course, any other material may be used as long as it has heat resistance and corrosion resistance) and has an internal space 24a, and its bottom 24b. Is formed with two mortar-shaped portions 34 narrowing downward (of course, the number of mortar-shaped portions 34 is not limited to two, and may be one or three or more). Has been. Further, an exhaust gas introduction duct connection hole 36 to which one end of the exhaust gas introduction duct 30 is connected is provided on the lower side surface of the casing 24, and one end of the exhaust gas outlet duct 32 is connected in the vicinity of the edge of the ceiling surface. An exhaust gas outlet duct connection hole 38 is provided, and a circulation exhaust gas outlet duct connection hole 48 to which a later-described circulation exhaust gas outlet duct 44 is connected is provided on the upper side surface of the casing 24.

  Note that the inner surface of the casing 24, the partition member 26, the exhaust gas introduction duct 30, or another duct inner surface, which will be described later, is corroded by a corrosive component such as hydrofluoric acid contained in the exhaust gas F or generated by decomposition of the exhaust gas F. Corrosion-resistant lining and coating with vinyl chloride, polyethylene, unsaturated polyester resin and fluororesin are applied to protect each part.

  The partition member 26 is installed in a horizontal direction substantially in the middle of the internal space 24a of the casing 24, and is made of a stainless steel plate that partitions the internal space 24a of the casing 24 into an upper space 24c and a lower space 24d (of course, heat resistance and corrosion resistance are improved). Any other material may be used as long as it has a material), and a plurality of communication holes 40 for communicating the upper space 24c and the lower space 24d with each other are provided on the surface thereof.

  The filter 28 has heat resistance (for example, if it is made of PTFE (tetrafluoroethylene resin), the heat resistance temperature is 260 ° C. or less). A long and narrow bag having a bottom 28a opened with a nonwoven fabric (felt) using fibers. The bottom portion 28a is attached in close contact with the communication hole 40 of the partition member 26 so that the exhaust gas F does not leak. In the present embodiment, three filters 28 are used. However, the number of filters 28 is not limited to three as a matter of course, and the flow rate of exhaust gas F to be treated, dust and fluoride in exhaust gas F, and the like. The number of filters 28 can be set according to the concentration of hydrogen or the like. The length of the filter 28 can also be set according to the concentration of dust, hydrogen fluoride or the like in the exhaust gas F, or the height of the upper space 24c of the casing 24. Further, the filter 28 may be disposed in the same direction as the flow direction of the exhaust gas F (that is, from bottom to top in FIG. 1) (FIG. 1 shows this mode), or the exhaust gas F. It may be arranged in the direction opposite to the flow direction (that is, from top to bottom in FIG. 1). However, when arranged in the opposite direction, a framework (not shown; generally referred to as “retainer”) for maintaining the shape of the filter 28 against the wind pressure of the exhaust gas F is provided in the filter 28. It is necessary to insert in.

  The exhaust gas introduction duct 30 is a stainless steel pipe that guides the exhaust gas F treated by the exhaust gas heating device 12 to the lower space 24d of the casing 24. As described above, one end of the exhaust gas introduction duct 30 is connected to the exhaust gas introduction duct connection hole 36 of the casing 24. The other end is connected to an exhaust gas discharge port (not shown) of the exhaust gas heating device 12. In addition, when the flow rate of the exhaust gas F is large, a square cylindrical duct made of a stainless steel plate may be used instead of a pipe.

  The exhaust gas outlet duct 32 is a stainless steel pipe that guides the exhaust gas F introduced into the upper space 24c from the upper space 24c of the casing 24 to the exhaust fan 16 after being filtered by the filter 28, and has one end thereof as described above. It is connected to the exhaust gas outlet duct connection hole 38 of the casing 24, and the other end is connected to the exhaust fan 16. Similarly to the exhaust gas introduction duct 30, the exhaust gas outlet duct 32 may use a square tube made of a stainless steel plate instead of a pipe when the flow rate of the exhaust gas F is large.

  The dropping device 33 is a device that applies stress to the filter 28 in order to remove dust, calcium fluoride, and the like adhering to the filter 28. FIG. 1 shows, as an example, a motor 33a and a motor 33a. The rotation shaft 33b and a rectangular plate-shaped paddle 33c attached to the distal end side of the rotation shaft 33b are shown. The horizontal width of the paddle 33c is set to be slightly larger than the interval between the filters 28. For this reason, when the motor 33a is operated, the paddle 33c rotates simultaneously with the rotation of the rotating shaft 33b. Both end portions of the paddle 33c periodically contact the filter 28 and press the outer surface of the filter 28. Deform. That is, stress is applied to the filter 28 by the paddle 33c, and dust, calcium fluoride, and the like accumulated inside the filter 28 can be removed.

  In the present embodiment, the paddle 33c is directly brought into contact with the filter 28 to deform the filter 28 to remove dust, calcium fluoride, etc., but high pressure compressed air is periodically blown onto the filter 28. Thus, the filter 28 may be deformed by the force of compressed air to remove dust, calcium fluoride, or the like, or the filter 28 may be vibrated using a vibration generator using an eccentric motor or the like. Dust, calcium fluoride, etc. may be wiped off from.

  The circulation part 22 is a part that circulates a part of the exhaust gas F after being filtered by the filter 28 from the upper space 24c to the lower space 24d of the casing 24 as the circulation exhaust gas CF. 44 and an exhaust gas introduction duct 46 for circulation.

  The circulation fan 42 is a turbo type fan that circulates a part of the exhaust gas F after being filtered by the filter 28 from the upper space 24c of the casing 24 to the lower space 24d (of course, the fan type is not limited to this, and other centrifugal fans). Alternatively, an axial fan can also be used.) The exhaust gas F, which is about 10 times the amount of exhaust gas introduced into the lower space 24d of the casing 24 from the exhaust gas introduction duct 30 (standard state conversion), can be circulated. Has the rated capacity.

  The circulation exhaust gas outlet duct 44 is a stainless steel pipe that guides the exhaust gas F dry-processed by the filtration dust collector 14 from the upper space 24 c of the casing 24 to the circulation fan 42, and one end thereof is provided at the upper end of the side surface of the casing 24. Further, the other end of the circulation exhaust gas is connected to the air inlet 42 a of the circulation fan 42. In addition, when the flow rate of the exhaust gas F is large, a square cylindrical duct made of a stainless steel plate may be used instead of a pipe.

  The circulation exhaust gas introduction duct 46 is a stainless steel pipe that guides the exhaust gas F sent from the circulation fan 42 to the lower space 24 d of the casing 24, and one end thereof is connected to the exhaust port 42 b of the circulation fan 42. Further, the other end side of the circulation exhaust gas introduction duct 46 is branched into two, and each of the branched exhaust gas introduction duct ends 46 a and 46 b of the two mortar-shaped portions 34 in the casing 24. It is connected to the bottom portions 34a and 34b.

  Further, at the ends 46a and 46b of the branched exhaust gas introduction ducts, there are electric ball valves (of course, other types of valves or dampers) as flow rate adjusting means 50 for adjusting the flow rate of the exhaust gas F to be circulated. 1), one flow rate adjusting means 50a is fully open, and the other flow rate adjustment valve 50b is fully closed (FIG. 1 shows this state). The flow rate adjusting means 50a is fully closed and the other flow rate adjustment valve 50b is fully open, and alternately repeats at predetermined time intervals according to an instruction from a timer (not shown). The operation pattern of the flow rate adjusting means 50 is not limited to this. A state where both the flow rate adjusting means 50 are closed or a state where both the flow rate adjusting means 50 are open exists in the series of operation patterns. May be.

  As shown in FIG. 2, the exhaust gas introduction duct 30 and the exhaust gas outlet duct 32 of each filtration type dust collector 14a, 14b have flow path opening / closing means for passing or blocking the exhaust gas F in the exhaust gas inlet duct 30 or the exhaust gas outlet duct 32. A ball valve 52 (of course, may be a valve of another type or a damper, and may be any operation means such as manual operation, electric operation or pneumatic operation).

  Of the pair of filter type dust collectors 14a and 14b, the first filter type dust collector 14a and the flow channel opening / closing means 52 provided on the upstream side thereof (that is, attached to the exhaust gas introduction duct 30 of the first filter type dust collector 14a). Of the exhaust gas introduction duct 30, the second filtration type dust collector 14b and the channel opening / closing means 52 provided on the downstream side thereof (that is, the second filtration type dust collector 14b). The exhaust gas outlet duct 32 between the exhaust gas outlet duct 32 and the flow path opening / closing means 52) attached to the exhaust gas outlet duct 32 is communicated with each other by a first communication duct 54a.

  Further, the first filtration type dust collector 14a and the flow path opening / closing means 52 provided on the downstream side thereof (that is, the flow path opening / closing means 52 attached to the exhaust gas outlet duct 32 of the first filtration type dust collector 14). The exhaust gas outlet duct 32, the second filter type dust collector 14b, and the channel opening / closing means 52 provided upstream thereof (that is, the channel attached to the exhaust gas introduction duct 30 of the second filter type dust collector 14). The exhaust gas introduction duct 30 with the opening / closing means 52) is in communication with each other by a second communication duct 54b.

  The first communication duct 54a and the second communication duct 54b are provided with a communication duct flow path opening / closing means 56 for conducting or blocking the exhaust gas F in the first communication duct 54a or the second communication duct 54b. Yes.

  The exhaust fan 16 is connected to the exhaust gas discharge duct 32 of the filtration dust collector 14, and when the exhaust fan 16 is operated, the upstream side of the exhaust fan 16 inside the exhaust gas abatement apparatus 10 is always at atmospheric pressure. The pressure is kept low (= negative pressure). For this reason, the exhaust gas F, dust in the exhaust gas F, a fluorine compound, or the like does not leak out from the exhaust gas abatement apparatus 10 by mistake.

  Next, the operation of the exhaust gas abatement apparatus 10 will be described. The exhaust gas F discharged from the semiconductor manufacturing apparatus A is introduced into the exhaust gas heating apparatus 12 and heated to oxidize and decompose harmful substances such as silane into silicon dioxide or nitrogen fluoride as described above. Is decomposed into hydrogen fluoride, which is rendered harmless.

  The exhaust gas F heated by the exhaust gas heating device 12 is introduced into the filtration dust collector 14, and the introduction path is a flow path opening / closing means provided in the exhaust gas introduction duct 30 or the exhaust gas outlet duct 32 of the filtration dust collector 14. 52 and the communication duct flow path opening / closing means 56 provided in the communication ducts 54a and 54b are operated to set the respective flow or blocking states. In FIG. 2, only the flow path opening / closing means 52 provided in the exhaust gas introduction duct 30 and the exhaust gas outlet duct 32 of the first filtration type dust collector 14a are in a flow state, and the other flow path opening / closing means 52 and the communication duct are in the flow state. The flow path opening / closing means 56 is in a shut-off state, and all the exhaust gas F from the exhaust gas heating device 12 is introduced into the first filtration type dust collector 14 (in the case of other introduction paths) Will be described later).

  Also, new slaked lime S is accommodated in advance in the lower space 24d of the casing 24 in the first filtration type dust collector 14 (see FIG. 1), and the main switch (not shown) of the filtration type dust collector 14 is turned on. Then, the circulation fan 42 is activated and the exhaust gas F from the upper space 24c to the lower space 24d of the casing 24 (in this stage, since the exhaust gas F has not yet been introduced into the filtration dust collector 14, strictly speaking, the previous stop At that time, the exhaust gas F) remaining in the upper space 24c is circulated. At this time, as described above, the two flow rate adjusting means 50 provided in the circulation exhaust gas introduction duct 46 branched into two are such that one of the flow rate adjusting means 50a is fully open and the other flow rate adjusting valve 50b. Is fully closed, and one flow rate adjusting means 50a is fully closed and the other flow rate adjustment valve 50b is alternately opened at predetermined intervals. Exhaust gas F from the fan 42 alternately repeats a state of jetting from one bottom 34 a and a state of jetting from the other bottom 34 b of the two mortar-shaped parts 34 in the casing 24.

  After the heat treatment by the exhaust gas heating device 12, the exhaust gas F introduced into the lower space 24 d of the casing 24 in the first filtration dust collector 14 a through the exhaust gas introduction duct 30 is stirred by the exhaust gas F from the circulation fan 42. While the slaked lime S is involved, it enters the filter 28 through the communication hole 40 of the partition member 26, and dust, hydrogen fluoride, etc. in the exhaust gas F react with the slaked lime S when passing through the filter 28. Calcium fluoride and the like produced in this manner and unreacted slaked lime S are filtered and adhere to the inner surface of the filter 28 and accumulate.

  The exhaust gas F filtered by the filter 28 enters the upper space 24c of the casing 24, and part of the exhaust gas F is again introduced into the lower space 24d of the casing 24 by the circulation fan 42 as the circulation exhaust gas CF, and the remaining exhaust gas F is Then, the exhaust gas enters the exhaust fan 16 through the exhaust gas discharge duct 32 and is discharged from the exhaust fan 16 to the outside of the exhaust gas abatement apparatus 10.

  The other introduction path | route at the time of introducing the waste gas F heat-processed with the waste gas heating apparatus 12 to the filtration dust collector 14 is demonstrated below.

  In FIG. 3, the flow path opening / closing means 52 provided in the exhaust gas introduction duct 30 and the exhaust gas outlet duct 32 of the first filtration type dust collector 14a and the exhaust gas introduction duct 30 and the exhaust gas outlet duct 32 of the second filtration type dust collector 14b are provided. The flow path opening / closing means 52 provided is in a flow state, and the two communication duct flow path opening / closing means 56 are both cut off. In this way, according to the introduction path connecting the two filter type dust collectors 14a and 14b in parallel, the exhaust gas F heated by the exhaust gas heating device 12 is converted into the first filter type dust collector 14a and the second filter type dust collector 14b. Therefore, it is possible to cope with a case where the amount of exhaust gas F to be processed is large.

  In FIG. 4, the flow path opening / closing means 52 provided in the exhaust gas introduction duct 30 of the first filtration dust collector 14a, the flow path opening / closing means 52 provided in the exhaust gas outlet duct 32 of the second filtration dust collector 14b, The communication duct flow path opening / closing means 56 provided in the second communication duct 54b is in a flow state, and the remaining flow path opening / closing means 52 and the communication duct flow path opening / closing means 56 are blocked. Thus, according to the introduction path (path A) connecting the two filtration type dust collectors 14a and 14b in series, the exhaust gas F heated by the exhaust gas heating device 12 is processed by the first filtration type dust collector 14a. Further, since it is processed by the second filtration type dust collector 14b, when the concentration of dust, hydrogen fluoride or the like in the exhaust gas F is high, or in the exhaust gas F discharged from the exhaust fan 16 to the outside of the exhaust gas abatement apparatus 10. It is possible to cope with the case where it is necessary to maximize the removal efficiency of dust, hydrogen fluoride, etc., such as when the concentration of dust, hydrogen fluoride, etc. needs to be extremely low.

  FIG. 5 also shows an introduction path for connecting two filtration type dust collectors 14 in series, but contrary to the case of FIG. 4, the exhaust gas F heated by the exhaust gas heating device 12 is the second filtration type. After being processed by the dust collector 14, it is further processed by the first filtering dust collector 14 (path B).

  When the exhaust gas abatement apparatus 10 is operated in the path A for a predetermined period and then switched from the path A to the path B, the first filtration type dust collector 14a into which the exhaust gas F having a high concentration such as dust and hydrogen fluoride has been introduced. The dust and calcium fluoride accumulated in the inside are taken out and replaced with new slaked lime S, and the second filtration type dust collector 14b is continuously operated as it is. And after operating for a predetermined period in the route B, when switching to the route A again, the dust and calcium fluoride accumulated in the second filtration dust collector 14b are taken out and replaced with new slaked lime S. The filter-type dust collector 14a is continuously operated as it is.

  As a result, as described above, the slaked lime S that is used in the filtration dust collector 14 having a lower concentration of hydrogen fluoride or the like in the introduced exhaust gas F and remains in a large amount is introduced after switching the route. Since it is used in the filtration type dust collector 14 having a higher concentration of hydrogen fluoride or the like in the exhaust gas F to be used, not only can the slaked lime S be used without waste, but also the fluorination in the exhaust gas F to be introduced. Since new slaked lime S is always used for the filtration type dust collector 14 having a lower concentration of hydrogen or the like, the opportunity for hydrogen fluoride or the like to contact the slaked lime S is maximized even if the concentration of hydrogen fluoride or the like is low. The slaked lime S can be used without waste, and the concentration of hydrogen fluoride or the like finally discharged from the exhaust gas abatement apparatus 10 can be minimized.

  In addition, about all the ducts connected to the filtration dust collector 14, as shown in FIG. 6, with respect to the end portion of each duct connected to the filtration dust collector 14, the opposite end portion is at a high position. A union joint 60 that can be joined or removed by simply rotating itself without rotating each duct may be attached to the opposite end.

  In this way, when taking out the filtered dust, calcium fluoride, etc. and replacing it with new slaked lime S, the risk of dust etc. in the lower space 24d of the filtering dust collector 14 spilling and scattering into the clean room is minimized. Can be

It is a conceptual diagram which shows the filtration type dust collector of this invention. It is a block diagram showing an exhaust gas abatement device of the present invention. It is a figure which shows the other introduction path | route to a set of filtration type dust collectors. It is a figure which shows the other introduction path | route to a set of filtration type dust collectors. It is a figure which shows the other introduction path | route to a set of filtration type dust collectors. It is a conceptual diagram which shows the other Example of the filtration type dust collector of this invention. It is a block diagram which shows the wet processing flow of the conventional waste gas. It is a block diagram which shows the dry-type processing flow of the conventional waste gas. It is a conceptual diagram which shows the conventional filtration type dust collector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exhaust gas abatement device 12 ... Exhaust gas heating device 14 ... Filtration type dust collector 16 ... Exhaust fan 20 ... Main body part 22 ... Circulation part 24 ... Casing 24a ... Internal space 24b ... Bottom part 24c ... Upper space 24d ... Lower space 26 ... Partition member DESCRIPTION OF SYMBOLS 28 ... Filter 30 ... Exhaust gas introduction duct 32 ... Exhaust gas extraction duct 33 ... Discharge device 34 ... Mortar-shaped part 36 ... Exhaust gas introduction duct connection hole 38 ... Exhaust gas extraction duct connection hole 40 ... Communication hole 42 ... Circulation fan 44 ... Exhaust gas for circulation Derivation duct 46 ... circulation exhaust gas introduction duct 48 ... circulation exhaust gas extraction duct connection hole 50 ... flow rate adjusting means 52 ... flow path opening / closing means 54 ... communication duct 56 ... communication duct flow path opening / closing means 60 ... union joint

Claims (5)

A casing having an internal space,
The internal space of the casing is partitioned into an upper space and a lower space into which exhaust gas and powdery slaked lime discharged from a semiconductor manufacturing apparatus and heated are introduced, and the lower space and the upper space communicate with each other A partition member having a communicating hole,
A filter attached to the communication hole, for filtering the exhaust gas guided from the lower space to the upper space through the communication hole;
One end is connected to a portion of the casing facing the lower space, the exhaust gas introduction duct for introducing the exhaust gas into the lower space, and one end is connected to a portion of the casing facing the upper space and filtered by the filter A main body provided with an exhaust gas exhaust duct for extracting the exhaust gas after the upper space;
A circulation fan for circulating a part of the exhaust gas after being filtered by the filter from the upper space to the lower space;
One end is connected to the portion of the casing facing the upper space, the other end is connected to the circulation fan, and the other end is connected to the circulation fan, and the other end faces the lower space. A batch-type filtration dust collector composed of a circulation unit having a circulation exhaust gas introduction duct connected to the bottom of the casing ,
The other end side of the exhaust gas introduction duct for circulation is branched into a plurality and connected to the bottom of the casing,
Each of the circulation exhaust gas introduction ducts branched into a plurality is provided with a flow rate adjusting means for adjusting the flow rate of the exhaust gas to be circulated,
The filtration type dust collector , wherein the flow rate adjusting means repeats full-close and full-open alternately every predetermined time according to an instruction from a timer, thereby generating a turbulent flow in the lower space of the casing . The bottom of the casing is composed of a plurality of mortar-shaped portions that narrow downward, and each of the circulation exhaust gas introduction ducts branched into a plurality is connected to the bottom of each mortar-shaped portion. The filtration dust collector according to claim 1. The filtration dust collector according to claim 1 or 2 , wherein a dusting device is provided for applying stress to the filter to wipe off slaked lime and dust adhering to the filter . An exhaust gas heating apparatus that receives exhaust gas discharged from a semiconductor manufacturing apparatus and heat-treats the exhaust gas at a high temperature;
The filtration dust collector according to any one of claims 1 to 3, which receives the exhaust gas discharged from the exhaust gas heating device;
An exhaust gas abatement apparatus comprising: an exhaust fan that exhausts the exhaust gas discharged from the filtration dust collector to the outside . An exhaust gas heating apparatus that receives exhaust gas discharged from a semiconductor manufacturing apparatus and heat-treats the exhaust gas at a high temperature;
A set of filtration type dust collectors according to any one of claims 1 to 3, which are arranged in parallel with each other and receive the exhaust gas discharged from the exhaust gas heating device;
An exhaust fan for exhausting the exhaust gas discharged from the filtration dust collector to the outside ;
A flow path opening / closing means provided on each of the exhaust gas introduction duct and the exhaust gas discharge duct of each of the filtration dust collectors, for opening and closing the flow paths of the exhaust gas introduction duct and the exhaust gas discharge duct;
The exhaust gas introduction duct between one of the filter-type dust collectors and the channel opening / closing means provided on the upstream side thereof, and the other filter-type dust collector and the channel opening / closing means provided on the downstream side thereof A first communication duct that communicates the exhaust gas outlet duct with each other,
The exhaust gas outlet duct between one of the filtration type dust collectors and the flow path opening / closing means provided on the downstream side thereof, and the other filtration type dust collector and the flow path opening / closing means provided on the upstream side thereof. A second communication duct that communicates the exhaust gas introduction duct with each other,
An exhaust gas abatement apparatus provided with communication duct flow path opening / closing means provided on the first and second communication ducts, respectively, for opening and closing the flow paths of the first and second communication ducts .

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