JP4350338B2 - Exhaust gas treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for performing a treatment for removing exhaust gas, and more particularly to an apparatus for removing harmful exhaust gas discharged when a semiconductor wafer is epitaxially grown into a harmless solid substance by contacting the cleaning liquid. is there.
[0002]
[Prior art]
A semiconductor device is produced by epitaxially growing a thin film on the surface of a semiconductor substrate.
[0003]
That is, a silicon substrate is generally used as the semiconductor substrate. For example, SiHCl3 (trichlorosilane) is used as the raw material gas for the thin film.
[0004]
SiHCl3 is supplied to the surface of the silicon substrate in the reaction furnace. Then, the same silicon thin film is formed by epitaxial growth on the surface of the silicon substrate by the chemical reaction of SiHCl3. For example, boron B having a predetermined concentration is added as an impurity to the epitaxial growth layer. Boron B is doped into the epitaxial growth layer by supplying a predetermined concentration of doping gas B2H6 into the furnace during the epitaxial growth process. In this way, an epitaxial growth layer to which a predetermined concentration of impurity B is added is formed on the surface of the silicon substrate.
[0005]
Epitaxial growth is performed in the growth furnace as follows. A single wafer furnace is assumed as an epitaxial growth furnace.
[0006]
A growth gas is supplied into the epitaxial growth furnace through a gas supply path. A growth gas comprising a source gas (SiHCl3), a doping gas (B2H6), and a carrier gas (H2) is supplied from an gas supply source into the epitaxial growth furnace.
[0007]
The epitaxial growth furnace is provided with a discharge port for exhausting the gas in the furnace to the outside.
[0008]
When the growth gas is supplied to the epitaxial growth furnace, the growth gas passes through the surface of the wafer substrate. The wafer substrate is held by a susceptor. A chemical reaction in a high-temperature gas phase (1000 ° C. to 1200 ° C.) is performed on the substrate, and impurities (B) are implanted at a predetermined concentration on the surface of the substrate to form a thin film. The growth gas that did not contribute to the chemical reaction in the high-temperature gas phase, the by-product gas that did not contribute to the epitaxial growth but did not contribute to the epitaxial growth, and the like are discharged to the outside from the discharge port.
[0009]
The susceptor is composed of SiC or the like. Therefore, unnecessary silicon is deposited when the source gas passes over the susceptor. Therefore, an etching gas is supplied into the epitaxial growth furnace through a gas supply path to remove the deposited silicon. HCl and carrier gas (H2) for diluting HCl as an etching gas are supplied from a gas supply source. Here, the etching gas may be a pure gas of hydrogen chloride gas or a mixed gas containing hydrogen chloride gas.
[0010]
When the etching gas is supplied into the epitaxial growth furnace, the etching gas passes through the surface of the susceptor. Thereby, unnecessary silicon deposited on the susceptor is decomposed and removed by etching gas and chemical reaction (Si (s) + 2HCl (g) → SiCl2 (g) + H2 (g)). A part of the etching gas contributing to the etching is discharged to the outside from the discharge port. Dozens of percent of the gas charged into the epitaxial growth furnace is exhausted as exhaust gas.
[0011]
The gases SiHCl 3, B 2 H 6, H 2, HCl, etc. thus discharged from the outlet of the epitaxial growth furnace are supplied to the abatement apparatus. It is generated into harmless substances by the abatement device and then released to the atmosphere.
[0012]
In particular, if silicon chloride such as SiHCl3 or hydrogen chloride HCl is released into the atmosphere as it is, it will adversely affect the human body and the like, so it must be converted into a harmless substance. HCl gas is corrosive and adversely affects equipment.
[0013]
Therefore, conventionally, the cleaning tower 50 shown in FIG. 9 is used to perform detoxification by “jet scrubber”.
[0014]
As shown in FIG. 9, a caustic soda aqueous solution 3 (NaOHaq) as a detoxifying agent is sucked up from a tank by a pump and supplied upstream of a jet nozzle 51 provided in the cleaning tower 50. On the other hand, the exhaust gas 4 is introduced from the introduction port 9 toward the outside of the nozzle 51. As a result, the caustic soda aqueous solution 3 as the jet stream 3A ejected from the nozzle 51 and the exhaust gas 4 drawn downstream of the nozzle 51 by the jet stream 3A are brought into gas-liquid contact, and the reaction formula (SiHCl3 + 2H2O → 3HCl + SiO2 + H2) (1) ) Produces a harmless solid substance, that is, a by-product 52 (SiO2 hydrate), and hydrogen chloride gas is detoxified by neutralization according to the reaction formula (HC1 + NaOH → NaCl + H2O (2)). The SiO2 hydrate 52 is dissolved in the aqueous caustic soda solution 3 and recovered and removed together with the aqueous caustic soda solution 3.
[0015]
[Problems to be solved by the invention]
However, according to the prior art shown in FIG. 9, the caustic soda aqueous solution 3 is rapidly bounced and scattered by the fast flow 3A of the caustic soda aqueous solution 3, and mist and water vapor are likely to be generated on the inner wall of the cleaning tower near the outlet of the nozzle 51. For this reason, before the exhaust gas 4 comes into gas-liquid contact with the main stream of the aqueous caustic soda solution 3, a part of it comes into contact with mist and water vapor, and a large amount of by-product 52 (solid SiO2 hydrate) is formed on the inner wall of the washing tower. Precipitates in a short time. For this reason, the passage of the exhaust gas 4 may be blocked in a short time due to the accumulation of the by-product 52.
[0016]
If the amount of deposited by-product 52 in the cleaning tower 50 is large and the cycle for closing the passage of the exhaust gas 4 is accelerated, there are problems in the following points.
[0017]
1) Normally, one cleaning tower 50 shown in FIG. 9 is assigned to one epitaxial growth furnace as a single wafer furnace. The cleaning tower 50 must be disassembled and cleaned in advance before clogging by the by-product 52 occurs. However, as the clogging cycle becomes shorter, the maintenance cycle for this disassembly and cleaning becomes shorter, and the opportunity to operate the epitaxial growth furnace is lost. Is called. For this reason, the downtime of the epitaxial growth furnace is increased and the operation efficiency is remarkably deteriorated.
[0018]
2) The SiO2 hydrate as the by-product 52 includes siloxane and the like. For this reason, a by-product is an active and highly ignitable substance, and if the amount of deposited deposits is large, the probability of matching with a disaster increases due to explosive combustion during decomposition cleaning work.
[0019]
Therefore, it is desired to reduce the amount of by-product 52 deposited and deposited and to lengthen the cycle of closing the passage of the exhaust gas 4.
[0020]
The present invention has been made in view of such a situation, and it is a first solution to suppress the amount of deposits of the by-product 52 to be small and to increase the cycle of closing the passage of the exhaust gas 4. It is what.
Here, the conventional general technical level concerning the problem that the by-product 52 is deposited in the cleaning tower 50 will be described.
[0021]
An abatement method disclosed in Japanese Patent Application Laid-Open No. 2001-7034 describes an invention in which a by-product deposited and accumulated on the inner end of the introduction pipe is removed by moving a scraping member in the exhaust gas introduction pipe. Yes.
[0022]
Further, the present invention is not described at all with respect to suppressing the precipitation of the by-product itself, and the precipitated by-product is removed later by a scraping member. Therefore, if the by-product precipitation rate is increased, before the by-product is removed by the scraping member, the by-product is clogged between the scraping member and the introduction pipe, and the removal itself cannot be performed. .
[0023]
Moreover, the technique which suppresses precipitation of the by-product 52 itself has already been implemented.
[0024]
That is, a gas curtain is made of dry nitrogen so that the mist and water vapor of the cleaning liquid 3 and the exhaust gas 4 are not in direct contact with each other, thereby preventing the by-product 52 from accumulating on the inner wall surface of the cleaning tower. However, this method has a problem that the configuration of the device becomes complicated and the running cost increases.
[0025]
In order to increase the efficiency of detoxification, the time and area during which the aqueous caustic soda solution 3 and the exhaust gas 4 are in gas-liquid contact may be increased to increase the efficiency of gas-liquid contact. In the case of the cleaning tower 50 of FIG. 9, if the flow of the jet stream 3A ejected from the nozzle 51 is increased, a larger amount of exhaust gas 4 can be drawn downstream of the nozzle 51 by the ejector effect, and the efficiency of gas-liquid contact is improved. Detoxification efficiency can be improved.
[0026]
In addition, since the pressure in the epitaxial growth furnace is not constant, it is necessary to adjust the flow velocity of the jet flow 3 </ b> A ejected from the nozzle 51 in order to stably draw the exhaust gas 4 to the downstream side of the nozzle 51.
[0027]
However, if the jet flow 3A ejected from the nozzle 51 is adjusted to increase the flow of the cleaning liquid 3, the flow of the exhaust gas 4 also increases accordingly, so that the detoxification efficiency is improved, but the speed of the aqueous caustic soda solution 3 itself is increased. Since it increases, the caustic soda aqueous solution 3 jumps up and becomes more noticeable. For this reason, the deposition amount of the by-product 52 in the cleaning tower 50 is further increased, the cycle in which the passage of the exhaust gas 4 is blocked is further accelerated, and the above problems 1) and 2) become more prominent. .
[0028]
The present invention has been made in view of such a situation, and a second problem to be solved is to improve the detoxification efficiency without increasing the jumping up and scattering of the aqueous caustic soda solution 3.
[0029]
[Means for solving the problems and effects]
  In order to achieve the first solution, the first invention of the present invention provides:
  The exhaust gas is guided to the cleaning tower, and the flow of the cleaning liquid is formed in the nozzle provided in the cleaning tower and the flow of the exhaust gas is formed outside the nozzle, and the exhaust gas and the cleaning liquid are brought into contact with each other at the tip of the nozzle. In the exhaust gas treatment device that performs the treatment to remove harmful substances in the exhaust gas,
  Inside the nozzle, the nozzleWall surface closest to the nozzle inside diameterAn inserter is provided to protrude further downward than the lower tip of,
  The lower end of the inserter is cylindrical
  It is characterized by.
[0030]
According to the first invention, as shown in FIG. 5, the inserter 29 is provided inside the nozzle 26 so as to protrude further downward than the lower tip of the nozzle 26.
[0031]
For this reason, the flux 3 c of the cleaning liquid 3 that passes between the nozzle 26 and the inserter 29 and is ejected from the tip of the nozzle 26 becomes thinner below the nozzle 26. As the flux 3c becomes thinner below the nozzle 26, the cleaning liquid 3 jumps up and is prevented from scattering. As a result, it is possible to suppress the deposition of the by-product 52 (solid SiO 2 hydrate) inside the cleaning tower 2, reduce the amount of the deposited by-product 52 in the cleaning tower 2, and reduce the exhaust gas 4. Cycles in which the passages are blocked can be lengthened.
[0032]
The second invention is the first invention,
The nozzle groove is a double groove
It is characterized by.
[0033]
According to the second invention, as shown in FIG. 3A, since the groove of the nozzle 26 is a double groove 26a, the cleaning liquid 3 ejected from the tip of the nozzle 26 is further suppressed from splashing and scattering. Can do. Thereby, it is possible to further suppress the deposition of the by-product 52 (solid SiO 2 hydrate) in the cleaning tower 2, reduce the deposition amount of the by-product 52 in the cleaning tower 2, and reduce the exhaust gas. The cycle in which the four passages are blocked can be lengthened.
[0034]
The third invention is the second invention,
Forming a groove on the outside of the double groove so as to protrude further downward;
It is characterized by.
[0035]
According to the third invention, as shown in FIGS. 3 (a) and 4, the groove 25a is formed on the outside of the double groove 26a so as to protrude further downward. It is possible to further suppress the splashing and scattering of the cleaning liquid 3 ejected from the nozzle. Thereby, it is possible to further suppress the deposition of the by-product 52 (solid SiO 2 hydrate) in the cleaning tower 2, reduce the deposition amount of the by-product 52 in the cleaning tower 2, and reduce the exhaust gas. The cycle in which the four passages are blocked can be lengthened. It is desirable that the groove 25a protrudes downward from the inserter 29 as shown in FIG.
[0036]
  A fourth invention is the first invention,
  Lower tip of the inserterThe cross-sectional area of the space sandwiched between the wall surface of the inserter and the wall surface closest to the nozzle inner diameter side is defined as the section of the space sandwiched between the wall surface of the inserter located above the lower tip and the wall surface closest to the nozzle inner diameter side. By making the area smaller than the area, the linear velocity of the flow of the cleaning liquid is increased around the lower tip than the periphery of the inserter located above the lower tip.
  It is characterized by.
[0037]
According to the fourth invention, as shown in FIGS. 3 (a) and 3 (c), since the restrictor 29a is formed at the lower tip of the inserter 29, the flux 3c of the cleaning liquid 3 ejected from the nozzle 26 is provided. And the linear velocity of the flux 3 c is made uniform in the circumferential direction of the inserter 29. For this reason, the splashing and scattering of the cleaning liquid 3 can be further suppressed.
[0038]
The fifth invention is the first invention, the second invention or the third invention,
Provided on the outside of the nozzle is a slide nozzle that slides toward the tip of the nozzle to remove by-products deposited on the tip of the nozzle.
It is characterized by.
[0039]
According to the fifth aspect of the invention, as shown in FIG. 1, a slide nozzle 27 is provided on the outer side of the outer nozzle 25 to remove the by-product 52 formed at the tip of the outer nozzle 25.
[0040]
Even if the by-product 52 is deposited on the front end portion of the outer nozzle 25, the by-product 52 deposited on the front end portion of the outer nozzle 25 is removed by sliding the slide nozzle 27 toward the front end portion of the outer nozzle 25. be able to.
[0041]
In particular, as shown in FIGS. 3 (a) and 4, an outer nozzle 25 is provided outside the inner nozzle 26 having a double groove 26a, and the groove 25a of the outer nozzle 25 is further below the double groove 26a. In the case where it is configured to protrude to the outside, as shown by an arrow C in FIG.
[0042]
Therefore, if the slide nozzle 27 is slid downward, the by-products 52 concentrated and deposited on the outer side of the outer end portion of the outer nozzle 25 can be collectively removed and removed.
[0043]
A sixth invention is the fifth invention,
The slide nozzle is driven by a gas pressure actuator that operates by the pressure of an inert gas.
It is characterized by.
[0044]
According to the sixth invention, as shown in FIG. 1, the slide nozzle 27 is driven by a gas pressure actuator (piston 32, chambers 33, 34) that operates by the pressure of an inert gas 5 such as nitrogen gas. Since an inert gas 5 such as nitrogen gas is used, even if a gas leak occurs, there is a possibility that explosive combustion may occur by reacting with an active substance such as the by-product 52 in the cleaning tower 2. Absent.
[0045]
A seventh invention is the first invention,
The cleaning liquid is discharged from a hole provided in the inner wall surface of the cleaning tower so as to form a flow of the cleaning liquid along the inner wall surface.
It is characterized by.
[0046]
According to the seventh invention, as shown in FIG. 7, the cleaning liquid 3 is discharged from the hole 31 provided in the inner wall surface 23a of the cleaning tower 2 (main duct 23), and the flow 3e of the cleaning liquid 3 is flown along the inner wall surface 23a. Forming. Therefore, as shown in FIG. 5, the flow 4c of the exhaust gas 4 and the flow 3e of the cleaning liquid 3 along the inner wall surface 23a are in gas-liquid contact at the gas-liquid contact portion 35 along the inner wall surface 23a. On the other hand, the flow 3 c of the cleaning liquid 3 ejected from the nozzle 26 comes into gas-liquid contact with the flow 4 c of the exhaust gas 4 at the gas-liquid contact portion 36 below the nozzle 26. Thus, the gas-liquid contact occurs between the nozzle 26 and the inner wall surface 23a of the cleaning tower 2, so that the efficiency of the gas-liquid contact is increased and the detoxification efficiency is improved.
[0047]
The eighth invention is the first invention, the second invention or the third invention,
A diffuser is formed outside the nozzle, exhaust gas is led to a passage formed between the diffuser and the nozzle, and an inert gas is purged into the exhaust gas passage to form a swirling flow to generate a negative pressure. To draw exhaust gas down the passage
It is characterized by.
[0048]
FIG. 6 schematically shows a cross section taken along the line AA in FIG.
[0049]
According to the fourth aspect of the present invention, the diffuser 24 is formed outside the outer nozzle 25, the exhaust gas 4 is led to the passage formed between the diffuser 24 and the outer nozzle 25, and the inert gas (nitrogen) is introduced into the passage of the exhaust gas 4. The gas) 6 is purged to form a swirl flow D, and the exhaust gas 4 is drawn downward by the negative pressure.
[0050]
By purging an inert gas 6 such as nitrogen gas into the passage of the exhaust gas 4, a swirling flow D is formed and a negative pressure is generated. More exhaust gas 4 can be drawn downstream by the negative pressure. Moreover, since it is the swirl | vortex flow D, the efficiency which contacts with the exhaust gas 4 increases. Therefore, the exhaust gas 4 is efficiently purged downward, the efficiency of gas-liquid contact between the exhaust gas 4 purged downward and the cleaning liquid 3 ejected from the outer nozzle 26 is increased, and the detoxification efficiency is improved.
[0051]
That is, the exhaust gas 4 can be efficiently drawn downstream without increasing the speed at which the cleaning liquid 3 is jetted. For this reason, it is possible to suppress an increase in splashing and scattering of the cleaning liquid 3 due to an increase in the ejection speed of the cleaning liquid 3.
[0052]
Therefore, according to the present invention, it is possible to improve the removal efficiency without increasing the splashing and scattering of the cleaning liquid 3.
[0055]
  Ninth inventionIsIn the first inventionThe exhaust gas is an exhaust gas discharged when epitaxially growing a semiconductor wafer.
[0056]
  Ninth inventionIs particularly applicable when exhaust gas 4 such as SiHCl 3, B 2 H 6, H 2, HCl, etc. discharged when epitaxially growing a semiconductor wafer is removed. When the abatement apparatus of the present invention is applied to the epitaxial growth furnace, the amount of deposited deposits of by-products 52 is reduced, and the maintenance cycle of the decomposing / cleaning work of the abatement apparatus is lengthened. Efficiency can be improved. The exhaust gas 4 discharged from the epitaxial growth furnace includes PH3, N2 and the like, and the content of the exhaust gas 4 varies depending on the type of raw material gas, dopant, etching gas, and the like.
[0057]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an exhaust gas abatement apparatus according to the present invention will be described below with reference to the drawings.
[0058]
FIG. 8 is a diagram showing an overall configuration of the exhaust gas treatment device 1 of the embodiment.
[0059]
In the previous process of the exhaust gas treatment apparatus 1, an epitaxial growth process for epitaxially growing a silicon thin film on a silicon substrate is performed in an epitaxial growth furnace.
[0060]
The epitaxial growth is performed by the following reaction, although it varies depending on the source gases SiCl4, SiHCl3, SiH2Cl2, and SiH4.
[0061]
(A) SiCl4 + 2H2 → Si + 4HCl (hydrogen reduction reaction) (3)
(B) SiHCl 3 + H 2 → Si + 3 HCl (hydrogen reduction reaction and thermal decomposition reaction) (4)
(C) SiH2Cl2 → Si + 2HCl (thermal decomposition reaction) (5)
(D) SiH4 → Si + 2H2 (thermal decomposition reaction) (6)
For example, SiHCl3 (trichlorosilane) (b) is used as a raw material gas for the silicon thin film. SiHCl3 is supplied to the surface of the silicon substrate in the reaction furnace. Then, the same silicon thin film is formed by epitaxial growth on the surface of the silicon substrate by the chemical reaction of SiHCl3. For example, boron B having a predetermined concentration is added as an impurity to the epitaxial growth layer. Boron B is doped into the epitaxial growth layer by supplying a predetermined concentration of doping gas B2H6 into the furnace during the epitaxial growth process. In this way, an epitaxial growth layer to which a predetermined concentration of impurity B is added is formed on the surface of the silicon substrate.
[0062]
That is, the growth gas is supplied into the epitaxial growth furnace through the gas supply path. A growth gas comprising a source gas (SiHCl3), a doping gas (B2H6), and a carrier gas (H2) is supplied from an gas supply source into the epitaxial growth furnace.
[0063]
The epitaxial growth furnace is provided with a discharge port for exhausting the gas in the furnace to the outside.
[0064]
When the growth gas is supplied to the epitaxial growth furnace, the growth gas passes through the surface of the wafer substrate. The wafer substrate is held by a susceptor. A chemical reaction in a high-temperature gas phase (1000 ° C. to 1200 ° C.) is performed on the substrate, and impurities (B) are implanted at a predetermined concentration on the surface of the substrate to form a thin film. Part of the growth gas that has contributed to the chemical reaction in the high-temperature gas phase is discharged to the outside through the discharge port.
[0065]
The susceptor is composed of SiC or the like. Therefore, unnecessary silicon is deposited when the source gas passes over the susceptor. Therefore, an etching gas is supplied into the epitaxial growth furnace through a gas supply path to remove the deposited silicon. HCl and carrier gas (H2) for diluting HCl as an etching gas are supplied from a gas supply source. Here, the etching gas may be a pure gas of hydrogen chloride gas or a mixed gas containing hydrogen chloride gas.
[0066]
When the etching gas is supplied into the epitaxial growth furnace, the etching gas passes through the surface of the susceptor. Thereby, unnecessary silicon deposited on the susceptor is decomposed and removed by an etching gas and a chemical reaction (Si (s) + 2HCl (g) → SiCl2 (g) + H2 (g)). A part of the etching gas contributing to the etching is discharged to the outside from the discharge port. Dozens of percent of the gas charged into the epitaxial growth furnace is exhausted as exhaust gas.
[0067]
Thus, the exhaust gas 4 discharged from the exhaust port of the epitaxial growth furnace, that is, SiHCl3, B2H6, H2, and HCl, is supplied to the exhaust gas processing apparatus 1 of FIG.
[0068]
However, the actual exhaust gas contains not only HCl and SiHCl3 but also SiH2Cl2 even if SiHCl3 is used as the source gas.
[0069]
Similarly, when the SiCl4 of (a) is used as the raw material gas, the actual exhaust gas similarly contains not only HCl and SiCl4 but also SiHCl3 and SiH2Cl2.
[0070]
That is, when the reaction formula (SiCl4 + 2H2 → Si + 4HCl) of (3) is accurately expressed, it is as follows.
[0071]
SiCl4 + H2⇔SiCl2 + 2HCl (7)
SiCl2 + H2⇔Si + 2HCl (8)
Here, the intermediate SiCl2 undergoes the following reaction reversibly with surrounding HCl and H2.
[0072]
SiCl2 + HCl⇔SiHCl3 (9)
SiCl2 + H2⇔SiH2Cl2 (10)
Therefore, in addition to H2 and HCl, not only SiCl4 but also SiHCl3 and SiH2Cl2 exist in the exhaust gas.
[0073]
Even when SiHCl3 is used as the source gas, not only SiHCl3 but also SiH2Cl2 exists in addition to HCl.
[0074]
However, in this embodiment, for convenience of explanation, it is assumed that only SiHCl3 is present as silicon chloride in the exhaust gas 4 when SiHCl3 is used as the source gas.
[0075]
Here, silicon chloride such as SiHCl3 and hydrogen chloride HCl are required to be converted into harmless substances because they are directly released into the atmosphere and adversely affect the human body. HCl gas is corrosive and adversely affects equipment. Therefore, these gases are removed by the exhaust gas treatment device 1 of FIG.
[0076]
The exhaust gas processing apparatus 1 in FIG. 8 mainly includes a cleaning tower 2, a treatment tank 13, and a pump 15 which will be described later with reference to FIG. The washing tower 2, the treatment tank 13, and the pump 15 are connected by various pipes.
[0077]
In the cleaning tower 2, detoxification is performed by a detoxification method called “jet scrubber” as in the prior art shown in FIG. 9. An inner nozzle 26 is provided inside the cleaning tower 2 as described in detail with reference to FIG. A supply port 11 upstream of the inner nozzle 26 is provided in the upper part of the cleaning tower 2.
[0078]
An inlet 9 for introducing exhaust gas 4 is provided at an intermediate position of the cleaning tower 2. The outer wall of the cleaning tower 2 constitutes a main duct 23 through which the exhaust gas 4 passes.
[0079]
A supply port 10 for supplying the cleaning liquid 3 to the inner wall of the main duct 23 is provided at a position below the cleaning tower 2.
[0080]
A caustic soda aqueous solution (NaOHaq) as the cleaning liquid 3 is stored in the treatment tank 13 below the cleaning tower 2. The cleaning liquid 3 is sucked up by the pump 15, supplied into the inner nozzle 26 through the pipe line 19 and the supply port 11, and supplied to the inner wall of the main duct 23 through the pipe line 16 and the supply port 10.
[0081]
A flow meter 20 for measuring the flow rate of the cleaning liquid 3 passing through the pipe line 19 is provided on the pipe line 19. A valve 21 for controlling the flow rate of the cleaning liquid 3 passing through the pipe 19 is provided on the pipe 19. The flow rate of the cleaning liquid 3 is measured by the flow meter 20, the valve 21 is controlled based on the measurement result, and the supply amount of the cleaning liquid 3 to the inner nozzle 26 is controlled to the target value. Then, an amount of the cleaning liquid 3 corresponding to the target value is ejected from the inner nozzle 26.
[0082]
Similarly, a flow meter 17 for measuring the flow rate of the cleaning liquid 3 passing through the pipe line 16 is provided on the pipe line 16. A valve 18 for controlling the flow rate of the cleaning liquid 3 passing through the pipe line 16 is provided on the pipe line 16. The flow rate of the cleaning liquid 3 is measured by the flow meter 17, the valve 18 is controlled based on the measurement result, and the supply amount of the cleaning liquid 3 to the inner wall of the main duct 23 is controlled to the target value. Then, an amount of the cleaning liquid 3 corresponding to the target value is discharged onto the inner wall surface of the main duct 23.
[0083]
The exhaust gas 4 discharged from the epitaxial growth furnace is introduced into the main duct 23 of the cleaning tower 2 through the inlet 9.
[0084]
As will be described later with reference to FIG. 1, supply exhaust ports 7 and 8 for supplying and discharging nitrogen gas 5 for driving a gas pressure actuator (referred to as “actuator driving nitrogen gas 5”) are provided in the upper portion of the cleaning tower 2. . A supply port 12 for supplying nitrogen gas 6 for purging in the diffuser (referred to as purge nitrogen gas 6) is provided below the cleaning tower 2 as will be described later with reference to FIG.
[0085]
Inside the cleaning tower 2, the cleaning liquid 3 and the exhaust gas 4 are brought into gas-liquid contact as a high-speed flow below the jet nozzle of the inner nozzle 26. When the cleaning liquid 3 and the exhaust gas 4 are brought into gas-liquid contact, a harmless solid substance, that is, a by-product 52 (a hydrate of SiO 2) is generated according to the reaction formula (SiHCl 3 + 2H 2 O → 3HCl + SiO 2 + H 2 (1)). The hydrogen chloride gas is detoxified by neutralization according to the formula (HC1 + NaOH → NaCl + H2 O (2)). The SiO2 hydrate 52 is dissolved in the caustic soda aqueous solution 3 and collected together with the caustic soda aqueous solution 3 in the treatment tank 13. Water is appropriately supplied to the treatment tank 13 from the outside, and the cleaning liquid 3 contaminated by the treatment bowl 13 is appropriately drained through the drainage channel 22. Further, the treatment tank 13 is provided with a pipe line 14 for releasing the atmosphere above the cleaning liquid 3 to the atmosphere 14. The pipe 14 is usually provided with a gas seal such as argon gas to prevent air from being blown into the treatment chamber 13.
[0086]
Next, the internal configuration of the cleaning tower 2 will be described with reference to FIG.
[0087]
As shown in FIG. 1, the cleaning tower 2 generally includes a main duct 23, a diffuser 24, an inner nozzle 26, an outer nozzle 25, an inserter 29, a slide nozzle 27, a piston 32, and chambers 33 and 34. It consists of and.
[0088]
The main duct 23 is a passage that constitutes the outer wall of the cleaning tower 2 and allows the exhaust gas 4 to pass therethrough. A plurality of holes 31 are formed in the inner wall surface 23a. The hole 31 is formed near the lower tip of the inner nozzle 26. The hole 31 communicates with the supply port 10 for the cleaning liquid 3.
[0089]
FIG. 7 is a perspective view of the main duct 23 in a perspective view. As shown in FIG. 7, when the cleaning liquid 3 is supplied to the supply port 10, the cleaning liquid 3 is discharged from the hole 31 and flows along the inner wall surface 23a, that is, along the tangential direction of the inner wall surface 23a. 3e is formed. As a result, the inner wall surface 23 a of the cleaning tower 2 is immersed in the cleaning liquid 3.
[0090]
Returning to FIG. 1, the inner nozzle 26 is a cylindrical member having a circular cross section, and is provided in the center of the cleaning tower 2 so that the longitudinal direction thereof coincides with the vertical direction of the cleaning tower 2. A supply port 11 is provided upstream of the inner nozzle 26. FIG. 3A and FIG. 4 are enlarged views of the lower end portion of the inner nozzle 26. As shown in FIG. 3A, the groove of the inner nozzle 26 is configured as a double groove 26a.
[0091]
Returning to FIG. 1, an inserter 29 is provided inside the inner nozzle 26. The inserter 29 is a member on a round bar having a circular cross section, and is provided so that the longitudinal direction thereof coincides with the longitudinal direction of the inner nozzle 26. FIG. 3A shows a side surface of the lower tip portion of the inserter 29, and FIG. 3B shows a cross section of the inserter 29 as viewed from the direction of arrow G in FIG.
[0092]
As shown in these drawings, the inserter 29 is provided such that its lower end protrudes further downward than the lower end of the inner nozzle 26.
[0093]
A plurality of grooves 30 are formed in the inserter 29 along the longitudinal direction thereof. The groove 30 extends to a predetermined position below the inserter 29. Accordingly, in the portion of the inserter 29 where the groove 30 is not formed, the cross-sectional area of the flow of the cleaning liquid 3 is smaller than that of the portion where the groove 30 is formed, so that the throttle portion 29a is configured (FIG. 3 ( a)).
[0094]
Therefore, when the cleaning liquid 3 is supplied from the supply port 11 as shown in FIG. 1, the cleaning liquid 3 passes through the groove 30 of the inserter 29 as shown by the arrow 3a, or the inner nozzle 26 and the inserter 29 as shown by the arrow 3b. Flows downward through the passage between and. Then, as indicated by an arrow 3d in FIG. 3A, when the flow of the cleaning liquid 3 reaches the constricted portion 29a, the cross-sectional area of the flow of the cleaning liquid 3 decreases, so that the linear velocity of the flow of the cleaning liquid 3 increases in the constricted portion 29a. To do. Then, the cleaning liquid 3 is ejected from the inner nozzle 26 at a high speed.
[0095]
FIG. 3C shows an inserter 29 equivalent to the inserter 29 of FIG. As shown in FIG. 3C, it is possible to configure the inserter 29 by combining members having different diameters. However, in this embodiment, the throttle portion 29a is formed by forming the groove 30 in the round bar. I have to. Since such a configuration is used, the strength can be increased and the flow velocity in the circumferential direction of the throttle portion 29a can be made uniform as compared with the configuration shown in FIG.
[0096]
Returning to FIG. 1, an outer nozzle 25 is provided outside the inner nozzle 26. The outer nozzle 25 is a cylindrical member having a circular cross section, and is provided such that its longitudinal direction coincides with the longitudinal direction of the inner nozzle 26.
[0097]
As shown in FIG. 3A, the outer nozzle 25 is provided such that its lower tip protrudes further downward than the lower tip of the inner nozzle 26. FIG. 4 is an enlarged view of the tip of the outer nozzle 25. As shown in FIG. 4, the tip of the outer nozzle 25 is formed with a groove 25a whose thickness decreases in a tapered shape toward the tip. ing. The groove 25a of the outer nozzle 25 is formed so as to protrude further downward than the double groove 26a of the inner nozzle 26.
[0098]
Returning to FIG. 1, a cylindrical slide nozzle 27 having a circular cross section is provided outside the outer nozzle 25. The slide nozzle 27 is slidably provided with respect to the outer nozzle 25 so that the longitudinal direction thereof coincides with the longitudinal direction of the outer nozzle 25.
[0099]
The slide nozzle 27 is driven by a piston 32 constituting a gas pressure actuator. The piston 32 is operated by the pressure of the nitrogen gas 5 for driving the actuator.
[0100]
That is, the piston 32 is connected to the upper part of the slide nozzle 27. A chamber 34 is formed above the piston 32, and a chamber 33 is formed below the piston 32. The upper chamber 34 communicates with the supply / discharge port 7. The lower chamber 33 communicates with the supply / discharge port 8.
[0101]
Therefore, when the actuator driving nitrogen gas 5 is supplied into the upper chamber 34 through the supply / discharge port 7 and the actuator driving nitrogen gas 5 is discharged from the lower chamber 33 through the supply / discharge port 8, The piston 32 moves downward by the pressure of the actuator driving nitrogen gas 5 in the side chamber 34. Along with this, the slide nozzle 27 connected to the piston 32 slides downward. Conversely, when the actuator driving nitrogen gas 5 is supplied into the lower chamber 33 through the supply / discharge port 8 and the actuator driving nitrogen gas 5 is discharged from the upper chamber 34 through the supply / discharge port 7, The piston 32 moves upward by the pressure of the actuator driving nitrogen gas 5 in the side chamber 33. Along with this, the slide nozzle 27 connected to the piston 32 slides upward.
[0102]
FIG. 1 shows a state in which the slide nozzle 27 is positioned at the uppermost position. When the slide nozzle 27 slides to the lowest position, the lower tip of the slide nozzle 27 reaches the lower tip of the outer nozzle 25. By sliding the slide nozzle 27 downward, the by-product 52 deposited on the outer tip of the outer nozzle 25 can be removed at the tip of the slide nozzle 27 as will be described later.
[0103]
Here, the nitrogen gas N2 is used as the actuator driving gas because, even if a gas leak occurs, it reacts with an active substance in the cleaning tower 2 such as the by-product 52, causing explosive combustion. This is to prevent the occurrence. Therefore, an inert gas such as an argon gas may be used as the actuator driving gas in addition to the nitrogen gas.
[0104]
A diffuser 24, which is a passage for the exhaust gas 4, is provided on the outer side of the outer nozzle 25 (slide nozzle 27). The diffuser 24 is arranged so that its upper end is positioned in the vicinity of the inlet 9 for the exhaust gas 4. The diffuser 27 is a substantially cylindrical member having a circular cross section, and is provided so that its longitudinal direction matches the longitudinal method of the outer nozzle 25 (slide nozzle 27).
[0105]
By providing the diffuser 24, a passage of the exhaust gas 4 is formed between the diffuser 24 and the outer nozzle 25 inside thereof, and a passage of the exhaust gas 4 is formed between the diffuser 24 and the main duct 23 outside thereof. Is done.
[0106]
FIG. 6 schematically shows a cross section taken along the line AA in FIG.
[0107]
As shown in FIG. 6, the diffuser 24 is formed with a plurality of pores 28 that guide the purge nitrogen gas 6 to the exhaust gas passage between the diffuser 24 and the outer nozzle 25. For example, 16 holes 28 are formed. As shown in FIG. 1, the hole 28 is disposed at an inclination of a predetermined angle θ, for example, 31 ° with respect to a vertical line as seen in a longitudinal section (see FIG. 1). In addition, as shown in FIG. 6, the holes 28 are arranged radially when viewed in cross section. The hole 28 communicates with the supply port 12 of the purge nitrogen gas 6.
[0108]
As shown by the arrow 4 a in FIG. 1, when the exhaust gas 4 is introduced from the introduction port 9, the exhaust gas 4 is guided to a passage formed between the diffuser 24 and the outer nozzle 25.
[0109]
On the other hand, when the purge nitrogen gas 6 is supplied to the supply port 12, as shown in FIG. 6, the purge nitrogen gas 6 passes through the hole 28 and is exhausted between the diffuser 24 and the outer nozzle 25. It is led to the gas passage. When the purge nitrogen gas 6 is introduced into the passage of the exhaust gas 4 through the holes 28, a downward swirling (tornado) flow D is formed. This downward swirling flow D generates a negative pressure (static pressure). Since such a negative pressure is generated, the exhaust gas 4 is drawn downward by the negative pressure. Further, since the swirl flow D, the contact area between the purge nitrogen gas 6 and the exhaust gas 4 is increased. For this reason, the exhaust gas 4 is efficiently purged from the lower end of the diffuser 24 as shown by an arrow 4c in FIG. Here, the nitrogen gas N2 is used as the purge gas 6 for the same reason as the actuator gas 5, and an inert gas such as an argon gas may be used instead of the nitrogen gas.
[0110]
Here, it is assumed that the hole 31 formed in the inner wall surface 23a of the main duct 23 is disposed in the vicinity of the lower end of the diffuser 24 (see FIG. 1).
[0111]
When the slide nozzle 27 is positioned at the uppermost position, it is assumed that the tip of the slide nozzle 27 is positioned in the nitrogen gas blowing direction of the hole 28 formed in the diffuser 24 (see FIG. 1).
[0112]
FIG. 2 shows the relationship among the tip positions of the inserter 29, inner nozzle 26, outer nozzle 25, and diffuser 24 described above. As shown in FIG. 2, the lower tip of the inserter 29 is positioned below the lower tip of the inner nozzle 26 by a distance a. The lower tip of the outer nozzle 25 is positioned below the lower tip of the inserter 29 by a distance b. Further, the lower tip of the outer nozzle 25 is positioned at the lower tip by a distance c from the lower tip of the diffuser 24. These distances a, b, and c have the highest gas-liquid contact efficiency (highest detoxification efficiency) depending on the diameter, length, etc. of the inserter 29, inner nozzle 26, outer nozzle 25, and diffuser 24. It is set to a value that minimizes splashing and scattering.
[0113]
In FIG. 1, reference numeral 37 denotes a cleaning nozzle. When the cleaning tower 2 is disassembled and cleaned, an outer nozzle in which by-products 52 are concentrated and deposited from the cleaning nozzle 37 toward the inside of the cleaning tower 2. A caustic soda aqueous solution as a cleaning liquid is ejected toward the outer front end portion of 25. Thereby, the active and easily ignited by-product 52 is dissolved and removed, and the cleaning and disassembling work of the cleaning tower 2 can be performed safely.
[0114]
Moreover, the material which comprises the washing tower 2 can use a vinyl chloride, for example, and can use SUS etc. suitably in the location where intensity | strength is required.
[0115]
At last, the operation and effect of the above-described configuration will be described.
[0116]
(1) About inserter 29
In the present embodiment, as described above, the inserter 29 is provided inside the inner nozzle 26 so as to protrude further downward than the lower tip of the inner nozzle 26.
[0117]
Therefore, as shown in FIG. 5, the flux 3 c of the cleaning liquid 3 that passes between the inner nozzle 26 and the inserter 29 and is ejected from the tip of the inner nozzle 26 is narrowed and narrowed below the nozzle 26. For this reason, the splashing and scattering of the cleaning liquid 3 are greatly suppressed. Thereby, it is possible to suppress the deposition of the by-product 52 (solid SiO 2 hydrate) in the cleaning tower 2, and to reduce the amount of the deposition of the by-product 52 in the cleaning tower 2, The cycle in which the passage of the exhaust gas 4 is blocked can be lengthened.
[0118]
(2) About the double groove 26a of the inner nozzle 26
In the present embodiment, the tip of the inner nozzle 26 is formed in a double groove 26a.
[0119]
For this reason, as shown in FIG. 3A, since the cleaning liquid 3 forms a vortex B at the double groove 26a of the inner nozzle 26, the cleaning liquid 3 ejected from the inner nozzle 26 jumps up and is prevented from scattering. Thereby, it is possible to further suppress the deposition of the by-product 52 (solid SiO 2 hydrate) in the cleaning tower 2, reduce the deposition amount of the by-product 52 in the cleaning tower 2, and reduce the exhaust gas. The cycle in which the four passages are blocked can be lengthened.
[0120]
By combining the inserter 29 and the double groove 26a described above, the cleaning liquid 3 can jump up and the effect of suppressing scattering can be further enhanced.
[0121]
(3) About the outer nozzle 25
In this embodiment, the groove 25a of the outer nozzle 25 is formed outside the double groove 26a of the inner nozzle 26 so as to protrude further downward.
[0122]
For this reason, as shown in FIGS. 3A and 4, the double groove 26 a of the inner nozzle 26 and the groove 25 a of the outer nozzle 25 are substantially combined to form a “triple groove”. Compared with the case where only the double groove 26a is provided, the splashing and scattering of the cleaning liquid 3 ejected from the inner nozzle 26 can be further suppressed. Thereby, it is possible to further suppress the deposition of the by-product 52 (solid SiO 2 hydrate) in the cleaning tower 2, reduce the deposition amount of the by-product 52 in the cleaning tower 2, and reduce the exhaust gas. The cycle in which the four passages are blocked can be lengthened.
[0123]
Further, as shown in FIG. 3A, the cleaning liquid 3 ejected from the inner nozzle 26 is concentrated and scattered on the outer tip of the outer nozzle 25 as shown by an arrow C, and is concentrated on the outer tip of the by-product 52. It can be deposited.
[0124]
The groove 25a of the outer nozzle 25 desirably protrudes downward from the inserter 29 as shown in FIG.
[0125]
(4) About the aperture 29a of the inserter 29
In the present embodiment, a throttle portion 29 a is formed at the lower end portion of the inserter 29.
[0126]
Therefore, as shown in FIG. 3A, the linear velocity of the flux 3c of the cleaning liquid 3 ejected from the inner nozzle 26 increases and the linear velocity is made uniform in the circumferential direction of the throttle portion 29a of the inserter 29. For this reason, compared with the case where the throttle part 29a is not provided, it is possible to further suppress the splashing and scattering of the cleaning liquid 3.
[0127]
(5) About slide nozzle 27
In the present embodiment, a slide nozzle 27 is provided on the outer side of the outer nozzle 25 to remove the by-product 52 formed at the outer tip of the outer nozzle 25.
[0128]
By providing the outer nozzle 25 as described above, the by-product 52 can be concentrated and deposited on the outer side of the front end portion of the outer nozzle 25.
[0129]
Further, as shown in FIG. 2, by appropriately setting the distances a, b, and c, it is possible to minimize the deposition amount of the by-product 52, and even if the by-product 52 is precipitated. The deposited portion can be concentrated on the outer front end portion of the outer nozzle 25.
[0130]
Therefore, when the slide nozzle 27 is slid downward, the by-products 52 concentrated and deposited on the outer tip of the outer nozzle 25 at the tip of the slide nozzle 27 are collectively removed.
[0131]
In the present embodiment, the outer nozzle 25 is provided outside the inner nozzle 26, but the outer nozzle 25 may be omitted. In this case, a slide nozzle 27 is slidably provided on the outer side of the inner nozzle 26, and the by-product 52 deposited on the lower tip of the inner nozzle 26 is cut off by the slide nozzle 27.
[0132]
(6) Gas pressure actuator (piston 32, chambers 33, 34) for driving the slide nozzle 27
In the present embodiment, the slide nozzle 27 is driven by a piston 32 that operates by the pressure of the nitrogen gas 5.
[0133]
In this embodiment, since the inert gas 5 such as nitrogen gas is used as the driving medium for the piston 32, even if a gas leak occurs, it reacts with an active substance such as the by-product 52 inside the cleaning tower 2. There is no risk of explosive combustion.
[0134]
However, the actuator for driving the slide nozzle 27 is arbitrary, and may be driven by a hydraulic pressure such as a hydraulic pressure in addition to the gas pressure. The actuator may be driven only by a mechanical element such as a ball screw without using a driving medium such as gas or oil. May be.
[0135]
In the present embodiment, the slide nozzle 27 is controlled by automatic control. For example, assuming that the epitaxial growth process is performed at 5 to 10 batches per hour in an epitaxial growth furnace, the slide nozzle 27 slides downward every four hours and repeats a series of operations of returning to the uppermost position. Do. The slide nozzle 27 operates every time the time set by the timer (4 hours) is reached. However, this is only an example, and a cycle for operating the slide nozzle 27 can be set in accordance with the amount of the by-product 25 deposited on the outer nozzle 25.
[0136]
It is also possible to control the slide nozzle 27 manually.
[0137]
(7) About the hole 31 provided in the inner wall surface 23a of the main duct 23 (cleaning tower 2)
In the present embodiment, as shown in FIG. 7, the cleaning liquid 3 is discharged from the hole 31 provided in the inner wall surface 23a of the cleaning tower 2, and a flow 3e of the cleaning liquid 3 is formed along the inner wall surface 23a.
[0138]
Therefore, as shown in FIG. 5, the flow 4c of the exhaust gas 4 passing through the passage between the outer nozzle 25 and the diffuser 24 and the flow 3e of the cleaning liquid 3 along the inner wall surface 23a are along the inner wall surface 23a. Gas-liquid contact is made at the gas-liquid contact portion 35. On the other hand, the flow 4 c of the exhaust gas 4 that has passed through the passage between the outer nozzle 25 and the diffuser 24 is in gas-liquid contact with the flow 3 c of the cleaning liquid 3 ejected from the inner nozzle 26 at the gas-liquid contact portion 36 below the inner nozzle 26. . As described above, the gas-liquid contact occurs both below the nozzle 26 and the inner wall surface 23a of the cleaning tower, so that the efficiency of the gas-liquid contact is increased and the removal efficiency is improved. Even if the mist and water vapor of the cleaning liquid 3 ejected from the inner nozzle 26 are scattered on the inner wall surface 23a, the flow 3e of the cleaning liquid 3 is formed along the inner wall surface 23a. The by-product 52 due to mist and water vapor is prevented from being deposited on the inner wall surface 23a.
[0139]
(8) About the hole 28 provided in the diffuser 24
In the present embodiment, as shown in FIG. 6, a diffuser 24 is formed outside the outer nozzle nozzle 25, and the exhaust gas 4 is guided to a passage formed between the diffuser 24 and the nozzle 26. Purge nitrogen gas 6 is purged into the passage through hole 28 to form swirl flow D, and exhaust gas 4 is drawn down the passage by negative pressure.
[0140]
By purging the purge nitrogen gas 6 into the passage of the exhaust gas 4, a swirling flow D is formed and a negative pressure is generated. Since the negative pressure is generated, more exhaust gas 4 can be drawn downstream. Further, since the swirl flow D, the area where the purge nitrogen gas 6 comes into contact with the exhaust gas 4 is increased. For this reason, the efficiency of purging the exhaust gas 4 from the diffuser 24 is improved.
[0141]
For this reason, the efficiency with which the exhaust gas 4 comes into gas-liquid contact with the cleaning liquid 3 ejected from the inner nozzle 26 is increased, and the removal efficiency is improved.
[0142]
In the present embodiment, the exhaust gas 4 is drawn downstream by forming a swirl flow D of the purge nitrogen gas 6, and the cleaning liquid is used to draw the exhaust gas 4 downstream as in the prior art shown in FIG. There is no need to increase the speed at which 3 is ejected. For this reason, it is possible to suppress an increase in splashing and scattering of the cleaning liquid 3 due to an increase in the ejection speed of the cleaning liquid 3.
[0143]
For this reason, according to this embodiment, the removal efficiency can be improved without increasing the splashing and scattering of the cleaning liquid 3.
[0144]
The supply amount of the purge nitrogen gas 6 is appropriately set so that the detoxification efficiency is maximized and the precipitation amount of the by-product 52 is minimized. For example, the purge nitrogen gas 6 is supplied to the supply port 12 at a flow rate of 60 L / min. The
[0145]
(9) Positional relationship between the slide nozzle 27 and the hole 28 formed in the diffuser 24 In this embodiment, as shown in FIG. 1, the slide nozzle 27 is formed in the diffuser 24 when it is positioned at the uppermost position. It arrange | positions so that the front-end | tip part of the slide nozzle 27 may be located in the nitrogen gas blowing direction of the hole 28. FIG. Therefore, the by-product 52 attached to the tip of the slide nozzle 27 when the by-product is missing by the slide nozzle 27 can be blown off by the purge nitrogen gas 6.
[0146]
Although it is desirable that all the configurations of (1) to (9) described above are implemented in combination, implementation of only one of (1) to (9) or implementation of appropriately combining two or more is also possible. .
[0147]
However, it is desirable that the configuration (1) in which the inserter 29 is provided is an essential configuration, and that (1) is combined with one or more of the other (2) to (9) as appropriate.
[0148]
However, the configuration (8) for generating the swirling flow D of the purge nitrogen gas 6 may be carried out independently without being combined with the configuration (1) in which the inserter 29 is provided. That is, the configuration (8) of generating the swirl flow D of the purge nitrogen gas 6 can be applied to a conventional cleaning tower in which the inserter 29 is not provided, for example, a conventional cleaning tower 50 shown in FIG. In this case, the exhaust gas 4 can be drawn downstream without increasing the speed of the cleaning liquid 3 ejected from the jet nozzle 51 in FIG. For this reason, the removal efficiency can be improved without increasing the splashing and scattering of the cleaning liquid 3.
[0149]
In the embodiment described above, it is assumed that the exhaust gas 4 discharged when epitaxially growing a semiconductor wafer is removed. When the abatement apparatus of the present invention is applied to the epitaxial growth furnace, the amount of deposited deposits of by-products 52 is reduced, and the maintenance cycle of the decomposing / cleaning work of the abatement apparatus is lengthened. Efficiency can be improved.
[0150]
However, the abatement apparatus of the present embodiment is not limited to the exhaust gas treatment of the epitaxial growth furnace, but is a furnace in which the abatement is caused by gas-liquid contact between the cleaning liquid and the exhaust gas and the deposition of by-products becomes a problem. If so, it can be applied to any furnace.
[Brief description of the drawings]
FIG. 1 is a diagram showing an internal configuration of a cleaning tower according to an embodiment.
FIG. 2 is a diagram showing the positional relationship of the lower tip of each nozzle in the cleaning tower.
FIG. 3 (a) is a view showing the flow of the cleaning liquid ejected from the tip of the nozzle, and FIG. 3 (b) is a cross-sectional view of FIG. FIG. 3C is a diagram equivalently showing the inserter shown in FIG.
4 is an enlarged view of a tip of an outer nozzle shown in FIG. 3. FIG.
FIG. 5 is a view showing a state in which exhaust gas and cleaning liquid are in gas-liquid contact under an inner nozzle.
6 is a cross-sectional view taken along the line AA of FIG. 1 and shows a state in which a swirling flow is formed by the purge nitrogen gas.
FIG. 7 is a perspective view showing the main duct shown in FIG. 1 as a cutaway view.
FIG. 8 is a diagram illustrating an overall configuration of an exhaust gas treatment apparatus according to an embodiment.
FIG. 9 is a diagram showing an internal configuration of a conventional cleaning tower.
[Explanation of symbols]
1 Exhaust gas treatment equipment
2 washing tower
3 Cleaning liquid (caustic soda solution)
5 Nitrogen gas for actuator drive
6 Nitrogen gas for purging
23 Main duct
24 Diffuser
25 Outer nozzle
26 Inner nozzle
27 Slide nozzle
28 holes
29 Inserter
29a Aperture
30 grooves
31 holes
32 piston
33 rooms
34 rooms
52 By-products

Claims (9)

The exhaust gas is guided to the cleaning tower, and the flow of the cleaning liquid is formed in the nozzle provided in the cleaning tower and the flow of the exhaust gas is formed outside the nozzle, and the exhaust gas and the cleaning liquid are brought into contact at the tip of the nozzle. In the exhaust gas treatment device that performs the treatment to remove harmful substances in the exhaust gas,
Inside the nozzle , an inserter is provided so as to protrude further downward than the lower end of the wall surface on the nozzle inner diameter side among the wall surfaces of the nozzle ,
An exhaust gas processing apparatus, wherein a lower end portion of the inserter is cylindrical . The exhaust gas processing apparatus according to claim 1, wherein the nozzle has a double groove. The exhaust gas processing apparatus according to claim 2, wherein a groove is formed on the outer side of the double groove so as to protrude further downward. The cross-sectional area of the space sandwiched between the wall surface of the lower tip portion of the inserter and the wall surface closest to the nozzle inner diameter side, the wall surface of the inserter positioned above the lower tip portion, and the wall surface closest to the nozzle inner diameter side The linear velocity of the flow of the cleaning liquid is increased around the lower tip than around the inserter located above the lower tip. The exhaust gas treatment device according to claim 1. The slide nozzle which drops off the by-product deposited on the front-end | tip part of the said nozzle by slid toward the front-end | tip part of the said nozzle outside the said nozzle is provided. The exhaust gas processing apparatus as described. The exhaust gas processing apparatus according to claim 5, wherein the slide nozzle is driven by a gas pressure actuator that is operated by a pressure of an inert gas. The exhaust gas processing apparatus according to claim 1, wherein the cleaning liquid is discharged from a hole provided in an inner wall surface of the cleaning tower to form a flow of the cleaning liquid along the inner wall surface. A diffuser is formed outside the nozzle, exhaust gas is guided to a passage formed between the diffuser and the nozzle, and an inert gas is purged into the exhaust gas passage to form a swirling flow to generate a negative pressure. The exhaust gas processing apparatus according to claim 1, wherein the exhaust gas is drawn downward by the passage. The exhaust gas processing apparatus according to claim 1 , wherein the exhaust gas is an exhaust gas discharged when epitaxially growing a semiconductor wafer.

Images