TWI527619B - Perfluoride treatment device and perfluoride treatment method - Google Patents

Description

Perfluorinated treatment device and perfluorinated treatment method

The present invention relates to a treatment apparatus for perfluorination or the like which is used, for example, to decompose a perfluorinated product.

For example, in the manufacturing process of a semiconductor device and a liquid crystal device, etching and cleaning are performed in order to form a fine pattern. At this time, the use of perfluorinated compounds is mostly the case. Further, perfluorinated materials are generally stable and harmless to the human body, and others are used, for example, in cold air.

However, most of these perfluorinated substances, once released into the atmosphere, will have a serious impact on the global environment. In other words, since it has a property of being stably present in the atmosphere for a long period of time and having a large global warming coefficient, it is one of the causes of global warming. Moreover, as described above, the perfluorinated compound is generally stable, and the effect thereof is continued for a long period of time.

Therefore, in order not to affect the global environment, it is necessary to decompose the used perfluorinated material into a state that is harmless to the global environment and then release it into the atmosphere.

Patent Document 1 discloses a method for decomposing a fluorine-containing compound, which is a gas stream of a fluorine compound containing only fluorine as a halogen. In the presence of water vapor, it is contacted with a catalyst at about 200 to 800 ° C. The catalyst is a catalyst containing Al composed of Al, Ni, Al and Zn, Al and Ti, and fluorine in the gas stream is converted into hydrogen fluoride.

Further, Patent Document 2 discloses a perfluorinated material processing apparatus comprising: a perfluorination decomposition apparatus provided with a catalyst layer, supplying exhaust gas containing perfluorinated substances, and decomposing perfluorinated acid; and acidity The material removal device removes the first reaction product generated by the reaction between the acidic substance contained in the exhaust gas discharged from the perfluorination decomposition apparatus and the Ca salt.

Further Patent Document 3 discloses a catalytic PFC decomposition treatment method which is characterized in that it contains at least a gas component which reacts with water to generate a solid matter, and a PFC in a PFC-containing gas stream is decomposed by a catalyst, characterized in that And a solid matter generating step of contacting a gas stream with water to cause solid matter; a solid matter trapping step of removing the generated solid matter; and a catalyst decomposition step of the PFC.

[prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2001-224926

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-246485

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2005-111423

Exhausted in the manufacturing process of the semiconductor device and the liquid crystal device In the gas, in addition to the perfluorinated substance, a substance in which a solid component is brought into contact with water to produce a solid component is contained. Further, the conventional method, as a pretreatment before decomposing the perfluorinated product, removes the acid gas by bringing the gas into contact with water or an aqueous alkali solution to produce a solid component such as hafnium halide. However, in this case, when a filter or the like for removing the generated solid component is used, there is a problem that water or the like is condensed on the filter or the like, so that the filter or the like is likely to be clogged in a short period of time.

The present invention has been developed in view of the above problems of the prior art.

That is, an object of the present invention is to provide a perfluorinated treatment apparatus which can be used as a pretreatment which does not require a method in which a perfluorinated gas is contacted with water or an aqueous alkali solution to produce a solid component, thereby avoiding use. A large amount of water and drainage treatment, and even if the perfluorinated gas contains moisture in addition to the perfluorinated gas, the filter or the like is less likely to be clogged.

As described above, according to the present invention, there is provided a perfluorinated processing apparatus comprising: a pretreatment means for pretreating a gas containing perfluorinated matter; and a heating means for containing a perfluorinated gas and The water is heated, and the perfluorinated product is hydrolyzed by a predetermined catalyst to generate a decomposition gas containing an acid gas; the heat exchange means is disposed in the front and rear portions of the heating means for containing the inflow before the heating means Heat exchange between the perfluorinated gas and water and the decomposition gas flowing out from the heating means; and the acid component removing means is carried out from the heat exchange means The decomposition gas after the removal removes the acid component in a dry manner; the pretreatment means includes a preheating means for heating the gas containing the perfluorinated product to evaporate the water of the liquid contained in the perfluorinated gas; and the solid component The removal means removes the solid component from the perfluorinated gas obtained by evaporating the liquid water by a preheating means.

Here, it is preferable that the preheating means arranges the fins in a flow path of a gas containing perfluorinated matter. Further, it is preferable to introduce air between the preheating means and the solid component removing means, and to pass the perfluorinated gas after introducing the air through the solid component removing means.

Further, it is preferable that the heat exchange means mix the water with the perfluorinated gas before flowing into the heating means.

Further, the solid component removing means preferably includes a first filter for removing solid components and a second filter for replacing the first filter when the first filter is replaced. The solid component is removed. Preferably, a compressed air port is provided on the downstream side of the flow path of the perfluorinated gas, and the compressed air port is used for backwashing the compressed air.

Further, according to the present invention, there is provided a method for treating a perfluorinated product, comprising: a pretreatment step of pretreating a gas containing perfluorinated matter; and a heating step of supplying a perfluorinated gas and water Heating, and hydrolyzing the perfluorinated product by a predetermined catalyst to generate a decomposition gas containing an acid gas; the heat exchange step is disposed in the front and rear stages of the heating step for containing the full portion before flowing into the heating step Fluoride gas and water and decomposition gas from the heating step And the acid component removing step, wherein the acid component is dry-removed by the decomposition gas flowing out from the heat exchange step; and the pre-treatment step includes: a preheating step of heating the gas containing the perfluorinated product to contain perfluoro The water of the liquid contained in the gas of the compound is evaporated; and the solid component removing step removes the solid component from the perfluorinated gas after the liquid water is evaporated by the preheating step.

The pretreatment means includes: a preheating means for heating a gas containing a perfluorinated substance to evaporate water of a liquid contained in a perfluorinated gas; and a solid component removing means for causing a liquid by a preheating means The perfluorinated gas after evaporation of water removes solid components; even if the perfluorinated gas contains moisture in addition to the perfluorinated product, the solid component removing means is less likely to clog.

The gas containing the perfluorinated gas is stirred in the preheating means so that the fins are disposed in the flow path of the perfluorinated gas containing the preheating means, so that the heat can be sufficiently transmitted to the perfluorinated gas.

Air is introduced between the preheating means and the solid component removing means, and the perfluoron-containing gas into which the air is introduced is passed through the solid component removing means, whereby the generation of carbon monoxide can be suppressed by the heating means, and the air contained in the air can be removed. Solid content.

The heat exchange means is such that water mixed with the perfluorinated gas before the first heating means is mixed, and the water used for the hydrolysis of the perfluorinated material can be more uniformly mixed in the perfluorinated gas.

The solid component removing means includes a first filter for removing solid components and a second filter for removing solid components instead of the first filter when the first filter is replaced. Thereby, since the second filter can be used even when the first filter is replaced, it can be replaced without stopping the operation of the apparatus.

The solid component removing means is provided with a compressed air port on the downstream side of the flow path of the gas containing the perfluorinated product, and the compressed air port is used for backwashing the compressed air, so that the treatment of the perfluorinated product does not have to be stopped, and It continues to operate and can extend the replacement period of filters and the like.

The pretreatment step includes: a preheating step of heating the gas containing the perfluorinated product to evaporate the water of the liquid contained in the perfluorinated gas; and removing the solid component from the liquid by the preheating means The perfluorinated gas after evaporation of the water removes the solid component; even if the perfluorinated gas contains water in addition to the perfluorinated product, the solid component removing means is less likely to clog.

1‧‧‧Semiconductor manufacturing equipment

2‧‧‧Perfluoride treatment unit

3‧‧‧acid scrubber

21‧‧‧Pre-processing unit

22‧‧‧Perfluorinated decomposition unit

23‧‧‧HF adsorption unit

24‧‧‧Control unit

211‧‧‧Inlet heater

211b‧‧‧Fins

212, 212a‧‧‧ filter

212b‧‧‧ nozzle

221‧‧‧1st heater

222‧‧‧2nd heater

231‧‧‧ heat exchanger

232‧‧‧acid component removal device

233‧‧‧Injector

Fig. 1 is an explanatory view showing the overall configuration of a semiconductor manufacturing plant to which the perfluorinated material processing apparatus of the present embodiment is applied.

Fig. 2 is an explanatory view showing a schematic configuration of a perfluorinated material processing apparatus of the present embodiment.

Fig. 3 is a schematic view showing the respective devices constituting the perfluorinated processing apparatus of the present embodiment. An explanatory diagram of the internal structure of the inlet heater 211.

Fig. 4 (a) to (b) are explanatory views of the internal structure of the inlet heater.

Fig. 5 is an explanatory diagram showing the relationship between the reaction temperature and the decomposition rate of perfluorinated compound.

Figure 6 is a flow chart showing the operation of the perfluorinated processing apparatus.

Fig. 7 is a view showing the processing apparatus of the actually manufactured perfluorinated product viewed from above.

Fig. 8 is a view showing a processing apparatus of a perfluorochemical actually manufactured as seen from the direction of VII of Fig. 7.

Hereinafter, the form of carrying out the invention will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit and scope of the invention. Further, the drawings used are for explaining the present embodiment and do not represent actual sizes.

<Description of the overall structure of the semiconductor manufacturing plant>

Fig. 1 is an explanatory view showing the overall configuration of a semiconductor manufacturing plant to which the perfluorinated material processing apparatus of the present embodiment is applied.

As shown in the figure, the semiconductor manufacturing facility of the present embodiment includes a semiconductor manufacturing facility for manufacturing a semiconductor, a perfluorination processing device 2 for decomposing a perfluorinated product, and an acid scrubber 3 for collecting acid gas. .

The semiconductor manufacturing equipment 1 is generally a clean room, and in the illustrated example, an oxide film etching of an oxide film such as a semiconductor wafer, a polycrystalline germanium P-Si etchant 11, and an etched insulating film of cerium oxide (SiO ₂ ) is provided. The device 12 and the metal etcher 13 for etching the metal film for use in wiring.

The P-Si etcher 11, the oxide film etcher 12, and the metal etcher 13 are dry etching (dry etching) devices, for example, reactive ion etching using a reactive etching gas in a process chamber (RIE: Reactive Ion Etching) ) device.

The etching gas systems used in the P-Si etcher 11, the oxide film etcher 12, and the metal etcher 13 are different, and the gas exhausted after dry etching of each device contains various perfluorinated species derived from the etching gas ( Hereinafter, it is also called PFC (perfluorocompound). This Example illustrates perfluorinated _{CF 4, C 2 F 6,} C 3 F 8, C 4 F 8, C 5 F 8, SF 6, CHF 3 and the like. Further, the exhaust gas containing the perfluorinated product, that is, the etched exhaust gas is removed by the toxic gas detoxification device 14 to remove a toxic gas such as chlorine (Cl ₂ ) gas, and then discharged to the outside of the semiconductor manufacturing equipment 1 by the collecting pipe 15. In the present embodiment, the etching exhaust gas outside the semiconductor manufacturing equipment 1 is discharged, and for example, 99% of the N ₂ (nitrogen) gas as the carrier gas contains a gas such as 1% perfluorinated product. In the present embodiment, the perfluorinated material contained in the etching exhaust gas is preferably 1% or less. Further, the flow rate of the discharged etching exhaust gas is, for example, 3000 L/min to 3500 L/min.

The perfluorinated processing apparatus 2 decomposes the perfluorinated substance contained in the etching exhaust gas discharged from the semiconductor manufacturing equipment 1 in detail, and removes the perfluorinated substance, and then discharges it as exhaust gas. Therefore, it is discharged from each device of the semiconductor manufacturing equipment 1, and the etched exhaust gas collected through the pipe is passed through three The valve 4 is introduced into the perfluorinated treatment device 2. The perfluorinated processing apparatus 2 does not need to be disposed in a clean room, and is usually disposed outside the semiconductor manufacturing apparatus 1.

The acid scrubber 3 traps acid gases. Further, the harmless gas after the acid gas is collected is discharged outside the semiconductor manufacturing plant. The acid scrubber 3 functions to trap the perfluorinated product even in the case where the perfluorinated processing apparatus 2 cannot completely remove the perfluorinated product. Further, even if the perfluorinated processing apparatus 2 malfunctions, it can function as a backup for the perfluorinated processing apparatus 2. That is, in the normal state, the perfluorochemical-containing gas system is introduced into the perfluorinated treatment device 2 through the three-way valve 4, and the perfluorinated product is decomposed by the perfluorinated treatment device 2. However, when the perfluorinated processing apparatus 2 malfunctions or the like, the three-way valve 4 is switched to directly introduce the perfluorinated gas into the acid scrubber 3.

Further, not shown in the first drawing, an alkali scrubber that traps acid gas contained in the etching exhaust gas discharged from the semiconductor manufacturing equipment 1 may be provided on the upstream side of the three-way valve 4.

<Description of Configuration of Perfluorinated Processing Apparatus>

Hereinafter, the perfluorinated processing apparatus 2 will be described in further detail.

Fig. 2 is an explanatory view showing a schematic configuration of a perfluorinated material processing apparatus 2 of the present embodiment.

As shown in the figure, the perfluorinated processing apparatus 2 includes a pre-processing unit 21 for pre-treating the introduced device inlet exhaust (etching exhaust gas); the perfluorination decomposition unit 22 is decomposed in the pre-processing unit 21 Pretreatment The perfluorinated product contained in the inlet and outlet of the apparatus; and the HF adsorption unit 23 are dry-removed so as to adsorb the decomposition gas containing HF (hydrogen fluoride) generated when the perfluorination unit 22 decomposes the perfluorinated compound. Then, the exhaust gas is detoxified by the inlet of each of the unit processing apparatuses, and then discharged as exhaust gas to the outside of the perfluorinated processing apparatus 2.

Fig. 3 is a schematic view showing the respective devices constituting the perfluorinated processing apparatus 2 of the present embodiment.

As described in FIG. 2, the perfluorinated processing apparatus 2 mainly includes a pretreatment unit 21, a perfluorination decomposition unit 22, and an HF adsorption unit 23. Further, as shown in the figure, the perfluorinated processing apparatus 2 includes a control unit 24 for controlling each of the devices and valves (not shown) included in the perfluorinated processing apparatus 2.

The pre-processing unit 21 is an example of a pre-processing means for pre-processing the device inlet exhaust. The pretreatment unit 21 includes an inlet heater 211 that performs preheating of the inlet and outlet of the apparatus, and filters 212 and 212a that remove the fine particles.

The inlet heater 211 is an example of a preheating means for heating the inlet and outlet of the apparatus to evaporate water, that is, fine water droplets (foils) of the liquid contained in the inlet and outlet of the apparatus. The inlet heater 211 is provided with a heater 211a around the pipe through which the exhaust gas of the device passes. Further, the device inlet exhaust is heated by the heater 211a when passing through the inlet heater 211, and is preheated to a temperature at which the mist evaporates. The temperature of the inlet venting of the preheated device at this time can be set, for example, to 60 °C. Thereby, it is possible to suppress the filter from being blocked by the mist at the next filter 212.

Figure 4 (a) ~ (b) is the inside of the inlet heater 211 An illustration of the structure of the part.

In the present embodiment, the inlet heater 211 is formed in a cylindrical shape. Further, the inlet of the apparatus is introduced from the upper portion of the drawing. Further, the device inlet exhaust gas flows in the lower direction in the drawing and is discharged from the lower portion in the drawing. Further, in the inlet heater 211, a fin 211b is disposed in a flow path of the exhaust gas at the inlet of the device.

In the example shown in Fig. 4(a), a plurality of disk-shaped fins 211b are disposed in the inlet heater 211. The disk-shaped fin 211b is inserted into the hole portion of the center portion to allow the holding member 211c to pass therethrough. Further, the fin 211b and the holding member 211c are joined to the hole portion by welding or the like. Thereby, the fins 211b are substantially parallel to each other in the vertical direction in the drawing and are arranged in a line at substantially equal intervals.

Moreover, in the example shown in FIG. 4(b), the fin 211b is joined to the inner wall of the inlet heater 211 by welding or the like. In this case, the fins 211b are arranged substantially parallel to each other in the vertical direction in the drawing, but are arranged in a zigzag shape in the vertical direction.

Due to the provision of such fins 211b, the air flow at the inlet of the device is disturbed. Therefore, the device inlet exhaust gas is stirred inside the inlet heater 211, and the heat generated by the heater 211a can be sufficiently transmitted to the device inlet exhaust gas. Further, in particular, in the configuration illustrated in Fig. 4(b), the heat generated by the heater 211a is further transferred by the fins 211b, so that it is easier to heat the device inlet exhaust. Further, in the manner in which the fins 211b are provided, the device inlet and exhaust are in contact with the fins 211b, and thus the contact portion is also subjected to the effect of removing moisture by condensation of moisture. In addition, at this time, the condensed moisture falls to the lower portion of the inlet heater 211, and there is an accumulation in the inlet plus The case of the bottom of the heater 211. Therefore, in the present embodiment, the bottom of the inlet heater 211 is provided with a valve 211d. Further, the valve 211d is periodically opened to discharge the water accumulated in the lower portion of the inlet heater 211.

Returning to Fig. 3, the filter 212 removes fine particles as solid components from the inlet and outlet of the apparatus after the mist is evaporated by the inlet heater 211. The semiconductor manufacturing equipment 1 generates fine particles such as ruthenium oxide which are eliminated in the above-described dry etching. Moreover, the fine particles are mixed into the inlet vent of the apparatus, and thus are removed by the filter 212. The filter 212 is not limited as long as it allows exhaust gas to pass through the inlet of the apparatus and can collect fine particles. For example, a mesh filter or the like can be used.

Further, in the present embodiment, in addition to the filter 212, a filter 212a is provided as an auxiliary filter, and a flow path for switching the inlet and outlet of the device is formed between the filter 212 and the filter 212a. The filter 212a has the same performance as the filter 212, but is smaller than the filter 212 and has a short period of use. Further, when the filter 212 is replaced or the like, the filter 212 is passed through the filter 212a instead of the filter 212 to remove solid components. Thereby, the replacement of the filter 212 can be performed without stopping the operation of the perfluorinated processing apparatus 2. In the present embodiment, the first filter filter 212 and the second filter filter 212a constitute a solid component removing means.

Further, in the present embodiment, air is introduced between the inlet heater 211 and the filter 212. Moreover, the inlet of the device into which the air is introduced is exhausted through the filter 212 or the filter 212a. In the next perfluorination unit 22, in order to suppress the production of carbon monoxide, there is a need for oxygen. Shape, so the air is mixed with the device inlet exhaust at this stage.

Further, as will be described later in detail, in the present embodiment, the exhaust gas passing through the apparatus 212 after passing through the filter 212 enters the heat exchanger 231 once. Then, the device inlet exhaust gas is heated by heat exchange in the heat exchanger 231. Further, at this time, in the next perfluorination decomposition unit 22, in order to decompose the perfluorinated compound, water required for the reaction is added in a liquid state. This water is heated in the heat exchanger 231 together with the device inlet exhaust gas to become water vapor of the gas. Moreover, it is transferred while being mixed with the exhaust gas of the device inlet. In the present embodiment, pure water is used for the water, and the amount added is in an amount corresponding to the reaction formula described later, for example, 350 mL/min. Further, the water may be added to the heat exchanger 231 by steam in advance.

Further, in the present embodiment, the filter 212 is provided with a nozzle 212b which is an example of a compressed air port for backwashing by compressed air on the downstream side of the flow path of the apparatus inlet exhaust. Further, the solid component deposited on the surface of the filter 212 is removed so that the compressed air is ejected from the nozzle 212b.

In the present embodiment, a pipe for supplying compressed air is connected to the nozzle 212b, and a valve 212e is provided in the middle of the pipe. Further, in the present embodiment, a differential pressure gauge 212c for detecting a pressure difference between the inlet and the outlet of the filter passing through the filter 212 is provided. When the pressure difference measured by the differential pressure gauge 212c reaches a predetermined value or more, the valve 212e is opened, and the compressed air is injected from the nozzle 212b to remove the solid component deposited on the surface of the filter 212. Furthermore, this processing can also be performed automatically. That is, the pressure difference measured by the differential pressure gauge 212c is monitored by the control unit 24 or the like, and When it is known that the pressure difference measured by the differential pressure gauge 212c reaches a predetermined value or more, the valve 212e is opened to transmit a control signal to inject compressed air. Also, in this case, the control signal of the closing valve 212e is transmitted after the predetermined time to stop the injection of the compressed air.

As described above, the solid content of the surface of the filter inlet and the exhaust gas introduction side of the filter 212 is removed by performing compressed air injection and backwashing, and the pressure difference can be reduced. Further, in the manner of performing the backwashing, the treatment of the perfluorinated product is not stopped, the operation can be continued, and the replacement period of the filter 212 can be extended.

The perfluorination decomposition unit 22 is an example of a heating means for heating the permeate of the apparatus and water, and hydrolyzing the perfluorinated product by a predetermined catalyst to generate a decomposition gas containing an acid gas. Further, the perfluorination unit 22 includes two heaters, a first heater 221 and a second heater 222.

The first heater 221 is internally provided with a heater 221a, and the heater 221a heats the inlet of the apparatus and the water which is added to the water vapor by the heat exchanger 231. The exhaust gas from the apparatus inlet after the first heater 221 is, for example, 450 ° C to 500 ° C. In the present embodiment, the first heater 221 is set such that the flow path of the device inlet exhaust is formed as a horizontal heater in the horizontal direction.

The second heater 222 introduces the exhaust gas from the inlet of the apparatus, and first heats the inlet and the steam of the apparatus by the heater 222a provided therein. Thereby the device inlet venting is heated, for example, to 750 °C.

Further, the device inlet exhaust gas to be further heated is connected to the catalyst layer 222b disposed under the second heater 222, and reacts with water (water vapor) mixed in the inlet of the device to be decomposed.

As a decomposition reaction at this time, a case where perfluorinated compounds are CF ₄ , CHF ₃ , C ₂ F ₆ and SF ₆ is taken as an example, and the following reaction formula is shown.

_{CF 4 + 2H 2 O → CO} 2 + 4HF ... (1)

CHF ₃ +(1/2)O ₂ +H ₂ O→CO ₂ +3HF...(2)

C ₂ F ₆ +3H ₂ O+(1/2)O ₂ →2CO ₂ +6HF...(3)

SF ₆ +3H ₂ O→SO ₃ +6HF...(4)

It is clear from the above formulas (1) to (4) that the perfluorinated compound is converted into a decomposition gas containing an acid component HF (hydrogen fluoride) by a hydrolysis reaction. Further, HF in this case can be captured as an acid gas contained in the decomposition gas.

Fig. 5 is an explanatory diagram showing the relationship between the reaction temperature and the decomposition rate of perfluorinated compound.

Here, as the perfluorinated compound contained in the etching exhaust gas, CF ₄ , CHF ₃ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₈ , C ₅ F ₈ , SF ₆ , and NF _{3 are} exemplified. Further, CO which is not a perfluorinated component among the components contained in the gas discharged from the semiconductor manufacturing equipment 1 is also collectively shown.

As shown in the figure, any component has a decomposition rate of approximately 100% at around 750 ° C so that it can react at a temperature of 750 ° C to substantially remove perfluorinated materials.

Further, in the present embodiment, as the catalyst constituting the catalyst layer 222b, Zn (zinc), Ni (nickel), Ti (titanium), F (fluorine), or Sn may be contained in Al ₂ O ₃ (alumina). (Thin), Co (cobalt), Zr (zirconium), Ce (铈), Si (矽) and other oxides. More specifically, for example, a composition of 80% by weight of Al ₂ O ₃ (alumina) and 20% by weight of NiO (nickel oxide) can be used.

In the second heater 222, the decomposition gas of HF containing the perfluorinated decomposition is discharged from the lower side of the second heater 222 and sent to the next HF adsorption unit 23. Further, at this time, the temperature of the decomposition gas discharged from the second heater 222 is about 600 ° C to 700 ° C.

The HF adsorption unit 23 is disposed in the front stage and the rear stage of the first heater 221 and the second heater 222, and includes a heat exchanger 231 that is connected to the apparatus inlet before flowing into the first heater 221 and from the second An example of a heat exchange means for exchanging heat between the decomposition gases after the heater 222 has flowed out; the acid component removal device 232 is a decomposition gas that has flowed out of the heat exchanger 231, and reacts the acid component with the calcium salt. An example of the means for removing the acid component by dry removal, and the ejector 233 is an example of an exhaust gas discharge means for discharging the exhaust gas after the acid component is removed by the acid component removing means 232.

Further, the HF adsorption unit 23 further includes a drug supply device 234, which is an example of a drug supply means for supplying a calcium salt of a drug for dry removal of HF from above the acid component removal device 232, and a drug discharge device 235 is derived from an acid. An example of a drug discharging means for discharging the used calcium salt below the component removing device 232; the HF concentration detector 236 monitors the concentration of HF contained in the gas discharged from the acid component removing device 232; and the powder trap 237, equipped with HF concentration detector Between the 236 and the ejector 233, the solid component produced is removed by the acid component removing device 232.

The heat exchanger 231 exchanges heat between the high-temperature decomposition gas discharged from the second heater 222 and the low-temperature device inlet exhaust gas before being introduced into the first heater 221. Thereby, the temperature of the decomposition gas is lowered, and the temperature of the inlet and outlet of the apparatus introduced before the first heater 221 is increased. Further, as described above, the heat exchanger 231 mixes the water with the device inlet exhaust gas before flowing into the first heater 221. Further, the water added to the heat exchanger 231 evaporates to form water vapor.

The temperature of the decomposition gas after passing through the heat exchanger 231 is lowered to about 300 ° C to 500 ° C, and the temperature of the exhaust gas passing through the heat exchanger 231 is increased to about 200 ° C to 300 ° C.

The heat exchanger 231 is not particularly limited, and a plate type heat exchanger in which two sheets are alternately arranged and a flow path is formed between the plates to exchange heat between the device inlet exhaust gas and the decomposition gas can be used; Among the casing (cylinder) and a plurality of branch pipe members (heat transfer pipes), a casing inlet and a decomposition gas are respectively passed through the casing, and a heat exchanger is exchanged between the casing and the tubular heat exchanger. Further, the double tube heat exchanger may be provided in a double tube structure, and the inner tube allows a high-temperature decomposition gas to flow therethrough, and the outer tube allows a low-temperature device inlet to flow therethrough. Further, the device inlet exhaust gas and the decomposition gas may flow in opposite directions or may flow in parallel. In the present embodiment, the double inlet heat exchanger is used to make the device inlet exhaust gas and the decomposition gas flow in opposite directions.

The acid component removing device 232 is filled with a drug layer 232a made of a calcium salt, and the HF contained in the decomposition gas is dry-removed so as to carry out an adsorption reaction with the calcium salt. As the calcium salt, CaCO ₃ (calcium carbonate), Ca(OH) ₂ (calcium hydroxide), CaO (calcium oxide) or the like can be used. Further, the shape of the calcium salt may be a powder, but it is preferably formed into a cylindrical shape or a spherical shape in terms of ease of handling. In the present embodiment, for example, a mixture of Ca(OH) ₂ and CaCO ₃ is used, and CaCO ₃ : Ca(OH) ₂ = 50% by weight to 80% by weight: 20% by weight to 50% by weight is used. In this case, the formability is good, and when it is used as a pellet, pulverization can be suppressed. Further, in the present embodiment, the mixture is used as a cylindrical particle having a diameter of about 3 mm on the bottom surface and a height of about 8 mm.

The adsorption reaction at this time is exemplified by the case where CaCO ₃ or Ca(OH) ₂ is used as the calcium salt, and the following reaction formula is shown.

CaCO ₃ +2HF→CaF ₂ +CO ₂ +H ₂ O...(5)

Ca(OH) ₂ +2HF→CaF ₂ +2H ₂ O...(6)

From the above formulas (5) to (6), it is understood that the HF system reacts with a calcium salt to produce CaF ₂ (calcium fluoride (fluorite), CO ₂ (carbon dioxide), and H ₂ O (water).

A compressed air pipe through which compressed air flows in is connected to the ejector 233, and the exhaust gas is sucked by the negative pressure generated by the compressed air at a high speed, and is discharged together with the compressed air to the outside of the perfluorinated processing apparatus 2. Thereby, the exhaust gas is further lowered in temperature and discharged. The exhaust gas discharged from the acid component removing device 232 is, for example, about 200 ° C, and the exhaust gas discharged from the ejector 233 is, for example, 100 ° C or lower.

Further, the decomposition gas system is introduced from below the acid component removing device 232, and is discharged from above the acid component removing device 232. Further, during the period in which the decomposition gas system flows upward from the lower side of the acid component removing device 232, a reaction with HF and a calcium salt exemplified in the above formulas (5) to (6) is generated, and HF is dry-removed. In this case, the calcium salt into CaF _2, since the reaction is not greater, the sequence must be replaced.

Therefore, in the present embodiment, the drug supply device 234 that supplies the calcium salt to the acid component removal device 232 and the drug discharge device 235 that discharges the used calcium salt from the acid component removal device 232 are provided.

In the present embodiment, the concentration of HF is monitored by the HF concentration detector 236, and when the concentration of HF reaches, for example, 100 ppm, it is determined that the calcium salt is replaced. Further, opening and closing of a roller valve (not shown) or the like provided in the medicine discharge device 235 is performed, and a predetermined amount of used calcium salt is discharged. Further, after the used calcium salt is discharged, opening and closing of a roller valve (not shown) or the like to the drug supply device 234 is performed, and a new amount of calcium salt is dispensed. In this manner, the calcium salts in the drug discharge device 235 are sequentially replaced. Further, the control unit 24 acquires information on the HF concentration from the HF concentration detector 236, and when the HF concentration reaches, for example, 100 ppm, the automatic setting of the roller valve of the medicine supply device 234 or the medicine discharge device 235 is automatically performed. Perform this series of procedures. Further, at this time, the calcium salt can be completely replaced, but usually only a part of it is replaced. The amount of replacement of the calcium salt is, for example, 40 kg/h.

The powder trap 237 is provided to remove the powder of the calcium salt generated by the acid component removing device 232 or the like in the case of replacement of the calcium salt. As the powder trap 237, a metal mesh filter or the like can be used.

<Description of the operation of the perfluorinated processing device>

Fig. 6 is a flow chart showing the operation of the perfluorinated processing apparatus 2.

Hereinafter, the operation of the perfluorinated processing apparatus 2 will be described using FIGS. 5 and 6.

First, the device inlet exhaust gas passes through the inlet heater 211 of the pre-processing unit 21 and is preheated (step 101). Thereby, the mist contained in the exhaust gas of the apparatus inlet is evaporated.

Next, air is introduced into the exhaust gas at the inlet of the preheated device, and the particles are removed by the filter 212 of the pretreatment unit 21 (step 102).

At this time, it is judged whether or not the filter 212 has to be replaced (step 103). Further, when it is necessary to replace the filter 212 (Yes in step 103), the flow path of the device inlet exhaust gas is switched to the auxiliary filter filter 212a side (step 104). Further, an operation of replacing the filter 212 is performed (step 105).

When the operation of replacing the filter 212 is completed, the flow path of the device inlet exhaust gas is switched to the filter 212 side of the original filter (step 106).

On the other hand, when it is not necessary to replace the filter 212 (No in step 103), the process proceeds to the next step 107. Further, it is determined whether or not the filter 212 has to be replaced, and the time during which the perfluorinated processing device 2 is operated after the replacement of the front filter 212 can be judged or visually judged.

Next, the device inlet exhaust system is heated by heat exchange by the heat exchanger 231 (step 107). Also, at this time, the fraction of perfluorinated The reaction is added to add the necessary water (step 108).

The exhaust gas passing through the apparatus inlet of the heat exchanger 231 is first heated by the first heater 221 (step 109), and further heated by the second heater 222 to a temperature necessary for decomposition of the perfluorinated product (step 110). . Further, when the catalyst layer 222b of the second heater 222 is decomposed, the perfluorination is decomposed, and the device inlet exhaust gas becomes a decomposition gas containing HF (step 111).

The decomposed gas enters the heat exchanger 231 again, and performs heat exchange with the inlet exhaust of the apparatus (step 112).

Further, the decomposition gas system is reacted with the calcium salt by the acid component removing device 232 to dryly remove the HF (step 113). Further, at this time, the control unit 24 determines whether or not the HF concentration acquired by the HF concentration detector 236 has reached a predetermined value or more (step 114). When the predetermined value or more is reached (Yes in step 114), the medicine discharge device 235 and the medicine supply device 234 are operated to replace the calcium salt (step 115). Moreover, when the predetermined value is not reached (No in step 114), the replacement of the calcium salt is not performed, and the process proceeds to the next step 116.

The exhaust gas after the HF dry removal is removed by the powder trap 237 (step 116), and the perfluorinated processing apparatus 2 is discharged by the ejector 233 (step 117).

The perfluorinated processing apparatus 2 detailed above has the following features.

(i) Since the perfluorination is decomposed by the catalyst layer 222b, a large amount of etching exhaust gas can be processed and the running cost can be reduced.

(ii) A method of removing HF by dissolving HF in water to remove HF by a method in which HF and a calcium salt contained in the decomposition gas are reacted by dry reaction, and HF-containing drainage is not generated. Further, CaF ₂ produced after the adsorption reaction is harmless and easy to handle. Further, since CaF ₂ is a raw material for producing HF, it is a valuable substance. That is, the valuable substance CaF ₂ can be produced from an etched exhaust gas which is harmful to the global environment.

(iii) The energy utilization efficiency can be improved by heat exchange between the device inlet exhaust gas and the decomposition gas by the heat exchanger 231. Moreover, drainage is not generated as compared with the case where the conventional decomposition gas is cooled by water. Therefore, the operation cost of the perfluorinated processing apparatus 2 can be reduced without requiring a drain treatment step.

(iv) The drug supply device 234 disposed above the acid component removing device 232 and the drug layer 232a having the drug discharging device 235 disposed below are assembled, and the gravity can be used by opening the valve, and the system can be easily installed by such a simple system. Replace the calcium salt. In the present embodiment, the decomposition gas is introduced from below, and is exhausted from above, and the HF concentration detector 236 is provided to determine the replacement period of the calcium salt so as to monitor the HF concentration. Thereby, the upper layer portion of the drug layer 232a is not discharged, and only the reacted calcium salt in the lower layer portion is discharged. Therefore, almost no unreacted calcium salt is generated, and the excessive consumption of calcium salt can be reduced.

(v) As the pre-processing unit 21, the inlet heater 211, the filters 212 and 212a are provided, so that a large amount of water and drainage treatment can be avoided in the pre-processing step. Further, in the case where the acid gas is contained in the exhaust gas at the inlet of the device, the acid component removing device is present in the present embodiment. 232, therefore, there are few cases where acid gas is discharged to the outside of the device.

<Explanation of actual perfluorinated processing device>

Fig. 7 is a view of the actually processed perfluorinated processing apparatus 2 as seen from above. Further, Fig. 8 is a view showing the actually processed perfluorinated processing apparatus 2 viewed from the VII direction of Fig. 7. That is, Fig. 8 is a view showing the treatment apparatus 2 of the perfluorinated product from the horizontal direction.

As shown in the figure, the actual perfluorinated processing apparatus 2 is disposed in substantially all of the inside of the rectangular region, regardless of the situation as viewed from above or from the horizontal direction. Further, the control unit 24 is disposed outside the rectangular area. Further, the rectangular rectangle in the present embodiment has a basic shape, but is similar to a rectangular ladder shape, a parallelogram shape, an elliptical shape, or the like, and may include a rectangular shape as long as it does not deviate from the characteristic range of the embodiment.

Next, description will be given of each device of the perfluorinated processing apparatus 2 in FIGS. 7 and 8. Hereinafter, when the position where the control unit 24 is provided is viewed from above, the lower left side of the processing device 2 for the perfluorinated product will be described.

The inlet vent of the apparatus is introduced into the inlet port In on the lower left side of the perfluorinated processing apparatus 2. Further, as shown in Fig. 8, it flows in the direction of the arrow A1 and passes through the inlet heater 211 provided on the lower side of the perfluorinated processing apparatus 2. Then, the heater 211a (see FIG. 3) disposed in the inlet heater 211 is preheated. Thereby, the mist contained in the exhaust gas of the device inlet is evaporated.

Venting through the inlet of the inlet heater 211, usually The flow is performed in the direction of the arrow A2 and the direction of the arrow A3 via a plurality of branch pipes, and is introduced into the filter 212. Further, the fine particles contained in the exhaust gas of the apparatus inlet are removed by the filter 212. Further, the device inlet exhaust system passing through the filter 212 flows in the direction of the arrow A4 toward the heat exchanger 231.

However, when the filter 212 is replaced, the flow path of the inlet of the apparatus is switched at the portion of the switching unit K. Then, the switching portion K flows in the direction of the arrow A5, and the filter 212a is introduced. Further, the fine particles contained in the exhaust gas of the apparatus inlet are removed by the filter 212a. Further, the device inlet exhaust system passing through the filter 212a flows in the direction of the arrow A6 toward the heat exchanger 231.

Further, although not shown, air is introduced into the apparatus inlet exhaust gas passing through the inlet heater 211 in the vicinity of the switching portion K.

The apparatus inlet exhaust gas passing through the filter 212 or the filter 212a flows in the direction of the arrow B through the pipe P1, and enters the heat exchanger 231 provided on the upper side of the perfluorinated processing apparatus 2. Further, the device inlet exhaust is heat-exchanged by the heat exchanger 231. Further, although not shown, water is added to the heat exchanger 231 at this time, and the water becomes steam and is transported together with the device inlet exhaust.

The device inlet exhaust gas discharged from the heat exchanger 231 flows in the direction of the arrow C through the pipe P2, and enters the first heater 221 provided on the lower right side of the perfluorinated processing device 2. The first heater 221 is a horizontal heater, and flows into the inlet of the device from the left side in Fig. 7, from Fig. 7 The middle right discharge device inlet is exhausted. Further, the first heater 221 is internally provided with a heater 221a (see FIG. 3), and the device inlet exhaust is heated when the inside of the first heater 221 moves from the left side to the right side.

Then, the device inlet exhaust gas discharged from the first heater 221 flows in the direction of the arrow D through the pipe P3, and enters the second heater 222 provided on the upper right side of the perfluorinated processing device 2. The second heater 222 is a vertical heater, and a heater 222a (see FIG. 3) is disposed above, and a catalyst layer 222b is disposed below (see FIG. 3). Further, the device inlet exhaust gas flows in from above the second heater 222, is heated by the heater 222a to the decomposition temperature of the perfluorinated product, and flows downward from the second heater 222. Further, in the catalyst layer 222b, the perfluorinated product reacts with water (water vapor) mixed with the inlet and outlet of the apparatus to decompose. Then, the acid decomposition gas containing the decomposition product HF is discharged from the lower side of the second heater 222.

Then, the decomposition gas system discharged from the second heater 222 flows in the direction of the arrow E by the pipe P4, and enters the heat exchanger 231 again. Then, in the heat exchanger 231, heat exchange is performed between the high-temperature decomposition gas and the low-temperature device inlet exhaust gas.

The decomposition gas system discharged from the heat exchanger 231 flows in the direction of the arrow F (the left direction in FIG. 7) through the pipe P5, and enters the acid component removing device 232 provided on the upper side of the perfluorinated processing device 2. At this time, the decomposition gas system flows in from below the acid component removing device 232 and flows upward above the acid component removing device 232. Further, at this time, in the drug layer 232a composed of a calcium salt (refer to Fig. 3), HF generated in the decomposition gas is generated. The adsorption reaction is dry removed. Then, it becomes a harmless exhaust gas and is discharged from the upper side of the acid component removing device 232.

The exhaust gas discharged from the acid component removing device 232 flows in the arrow G direction (the left direction in FIG. 7) through the pipe P6, and enters the powder trap 237 provided on the upper left side of the perfluorinated processing device 2. Further, the calcium salt powder or the like is removed by the powder trap 237. Further, in the middle of the pipe P6, the HF concentration detector 236 is disposed, and the HF concentration contained in the exhaust gas is measured. Further, in the present embodiment, the pipe P6 is long and has fins around it. In other words, the piping P6 connected to the ejector 233 is connected to the other side of the rectangular region, and the heat dissipating fins for cooling the exhaust gas are provided. Thereby, the temperature of the exhaust gas can be further reduced.

Further, the exhaust gas discharged from the powder trap 237 is finally sucked by the ejector 233 provided on the upper left side of the perfluorinated processing apparatus 2, and the pipe P7 is directed in the direction of the arrow H (upward direction in Fig. 7). The flow is discharged from the discharge port Ou to the outside of the device.

Further, the method for treating a perfluorinated product of the perfluorinated processing apparatus 2 described above includes a pretreatment step of pretreating the inlet and outlet of the apparatus, and a heating step of heating the inlet and the outlet of the apparatus. And the perfluorinated product is hydrolyzed by a predetermined catalyst to generate a decomposition gas containing an acid gas; and the heat exchange step is disposed in the front and rear portions of the heating step for introducing the exhaust gas and the water at the inlet of the device before the heating step And heat exchange between the decomposition gas flowing out from the heating step; and an acid component removal step of decomposing the gas after flowing out from the heat exchange step to dry the acid component The pretreatment step includes: a preheating step of evaporating the water of the liquid contained in the perfluorinated gas by heating the inlet of the apparatus; and removing the solid component from the liquid by the preheating step The perfluorinated gas after evaporation of water removes solid components; the present invention is a method for treating perfluorinated compounds having the above characteristics.

Further, in the above example, the case of treating the perfluorinated substance contained in the etching exhaust gas discharged from the semiconductor manufacturing plant has been described, but it is of course not limited thereto. For example, it is also possible to treat the etched exhaust gas discharged from the liquid crystal manufacturing plant or the like and the perfluorinated matter contained in the exhaust gas.

2‧‧‧Perfluoride treatment unit

4‧‧‧Three-way valve

21‧‧‧Pre-processing unit

22‧‧‧Perfluorinated decomposition unit

23‧‧‧HF adsorption unit

24‧‧‧Control unit

211‧‧‧Inlet heater

211a‧‧‧heater

212, 212a‧‧‧ filter

212b‧‧‧ nozzle

212c‧‧‧Differential Pressure Gauge

212e‧‧‧ valve

221‧‧‧1st heater

221a, 222a‧‧‧ heater

222‧‧‧2nd heater

222b‧‧‧ catalyst layer

231‧‧‧ heat exchanger

232‧‧‧acid component removal device

232a‧‧‧ drug layer

233‧‧‧Injector

234‧‧‧Pharmaceutical supply device

235‧‧‧Drug discharge device

236‧‧‧HF concentration detector

237‧‧‧Powder trap

Claims (7)

An apparatus for treating a perfluorinated product, comprising: a pretreatment mechanism for pretreating a gas containing perfluorinated matter; and a heating mechanism for heating a gas containing perfluorinated water and water, and by Al _{The 2} O ₃ type catalyst hydrolyzes the perfluorinated product to generate a decomposition gas containing an acid gas; the heat exchange mechanism is disposed in the rear stage of the pretreatment mechanism and is disposed in the front and rear sections of the heating mechanism for containing Heat exchange between the perfluorinated gas and water before flowing into the heating means and the decomposition gas flowing out of the heating means; and the acid component removing means is a dry gas after the gas is discharged from the heat exchange means The pretreatment mechanism includes a preheating mechanism that heats a gas containing perfluorinated substances to evaporate water of a liquid contained in the perfluorinated gas, and a solid component removing mechanism from the foregoing The heat mechanism removes the solid component filter by the perfluorinated gas after the liquid water is evaporated. The apparatus for treating a perfluorinated product according to claim 1, wherein the preheating means arranges the fins in a flow path of a gas containing perfluorinated matter. The apparatus for processing a perfluorinated product according to claim 1 or 2, wherein air is introduced between the preheating means and the solid component removing means, and a perfluoron-containing gas after introducing air passes through the solid component. Remove the mechanism. The apparatus for treating a perfluorinated product according to claim 1 or 2, wherein the heat exchange means mixes the water with a perfluorinated gas before flowing into the heating means. The apparatus for processing a perfluorinated product according to claim 1 or 2, wherein the solid component removing means includes a first filter for removing solid components and a second filter, wherein the second filter is used for performing When the first filter is replaced, the solid component is removed instead of the first filter. The apparatus for processing a perfluorinated product according to claim 1 or 2, wherein the solid component removing means is provided with a compressed air port on a downstream side of a flow path of a gas containing perfluorinated gas, and the compressed air port is used for Compressed air is backwashed. A method for treating a perfluorinated product, comprising: a pretreatment step of pretreating a gas containing perfluorinated matter; and a heating step of heating a gas containing perfluorinated water and water, and by Al ₂ O ₃ catalyst the class of perfluorinated hydrolysis decomposition gas containing acid gas; heat exchange step, disposed in line with the pre-stage and the processing step disposed in the preceding and succeeding stage heating step, for the inflow Heat exchange between the perfluorinated gas and water before the heating step and the decomposition gas flowing out from the heating step; and an acid component removal step, wherein the decomposition gas flowing out from the heat exchange step is dry The pretreatment step includes: a preheating step of heating the gas containing the perfluorinated product to evaporate the water of the liquid contained in the perfluorinated gas; and removing the solid component by the preheating The step of removing the solid component filter by the perfluorinated gas after evaporation of the liquid water.