JP2006158990A - Detoxifying apparatus and its management method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detoxifying apparatus capable of certainly determining breakthrough of a detoxifying agent filled in a detoxifying cylinder, and its management method. <P>SOLUTION: In the detoxifying apparatus, a gas containing a harmful component is introduced into the detoxifying cylinder filled with the detoxifying agent to perform removal treatment of the harmful component. A main detoxifying agent 14 and a sub-detoxifying agent 15 having different reaction form with the harmful component are used as the detoxifying agent and the sub-detoxifying agent is arranged in the detoxifying cylinder 13 at a downstream side in a gas flowing direction of the main detoxifying agent. A gas component measurement means (analyzer 16) for measuring a gas component produced by the reaction of the main detoxifying agent or the sub-detoxifying agent with the harmful component is provided on a treatment gas leading out part 12 for leading out the gas after the removal treatment of the harmful component is performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an abatement apparatus and a management method thereof, and more specifically, an abatement apparatus for removing harmful components in a gas discharged from a semiconductor manufacturing apparatus or the like from the gas, and an abatement agent in the abatement apparatus. The present invention relates to a management method for determining replacement time.

  Exhaust gases containing these toxic components are discharged from semiconductor manufacturing devices that use toxic inorganic components such as volatile inorganic hydrides, volatile inorganic halides, and organometallic compounds. These harmful components are dangerous and toxic and flammable, and must be detoxified before the exhaust gas is released into the atmosphere. For this reason, various detoxifying agents (removing agents) for removing harmful components from the exhaust gas by reacting with the harmful components have been developed, and in recent years, the exhaust gas is disposed in the detoxification cylinder filled with the detoxifying agent. Dry detoxification devices that distribute and detoxify are widely used.

Further, if the detoxifying agent breaks through with the progress of the removal process, the removal process of harmful components cannot be continued. For this reason, an analyzer is installed at the gas outlet (process gas outlet) of the detoxification cylinder to measure the concentration of harmful components, and when the concentration of harmful components exceeds the specified concentration, it is determined that the detoxifying agent has passed through. And a method of using a detection agent that changes color upon contact with harmful components and determining that the detection agent has changed color as breakthrough of the detoxifying agent (see, for example, Patent Document 1). .
JP-A-6-319945

  However, in the method of measuring the concentration of harmful components with the analyzer, the harmful components flowing out from the detoxification cylinder are analyzed, so the harmful components flow out downstream of the analyzer. It is necessary to provide an abatement means. In addition, with detection agents, if the gas flow in the detoxifying cylinder is uneven and the contact between the harmful components and the detection agent is not sufficient, the detection agent may not be discolored even if the detoxifying agent breaks through. is there. For this reason, restrictions have arisen in the size, shape, etc. of the abatement cylinder. Furthermore, since the discoloration of the detection agent is visually confirmed, the installation position of the abatement cylinder is also limited.

  Therefore, an object of the present invention is to provide an abatement apparatus and a management method thereof that can reliably determine the breakthrough of the detoxifying agent filled in the abatement cylinder.

  In order to achieve the above object, a detoxifying apparatus of the present invention is the detoxifying apparatus for removing a harmful component by introducing a gas containing a harmful component into a detoxifying cylinder filled with a detoxifying agent. As a harmful agent, using a main harmful agent and a secondary harmful agent having a different reaction form with the harmful component, and arranging the secondary harmful agent on the downstream side in the gas flow direction from the primary harmful agent, Gas component measuring means for measuring a gas component generated by a reaction between the main or secondary detoxifying agent and the harmful component in a processing gas deriving unit for deriving a gas after performing the removal processing of the harmful component It is characterized by providing.

  In the above configuration, the gas component measuring means is generated by a reaction between the sub-detoxifying agent and the harmful component and is not generated by a reaction between the main detoxifying agent and the harmful component, or a gas component with a small production amount. Or measuring a gas component produced by the reaction of the main harmful agent and the harmful component and not generated by the reaction of the auxiliary harmful agent and the harmful component or a small amount of the produced gas It is characterized by.

  Further, the management method of the abatement apparatus according to the present invention determines that the time when the concentration of the gas component generated by the reaction between the sub-detergent and the harmful component is increased is the replacement time of the harmful agent, The time when the concentration of the gas component generated by the reaction between the detoxifying agent and the detrimental component decreases is determined as the time for replacement of the detoxifying agent.

  According to the present invention, the change in the gas component concentration derived from the processing gas deriving unit of the detoxification cylinder, for example, the reduction of the gas component generated only by the reaction between the harmful component and the main detoxifying agent, or the harmful component By using the increase in gas components generated only by reaction with the sub-detoxifying agent as a criterion, it is possible to reliably know the breakthrough of the main detoxifying agent. Moreover, even if the main harmful chemicals break through, the harmful chemicals can be removed by the secondary harmful chemicals, so that no harmful chemicals will flow out.

  FIG. 1 is a schematic system diagram of an abatement apparatus showing an embodiment of the present invention. This abatement device has a gas introduction unit 11 for introducing a gas containing a harmful component and a treatment gas deriving unit 12 for deriving the gas subjected to the removal process, and is disposed upstream in the gas flow direction. The main detoxifying agent 14 is filled with a sub-detoxifying agent 15 laminated on the downstream side, and an analyzer 16 as a gas component measuring means is provided in the processing gas deriving unit 12.

The main detoxifying agent 14 and the sub-detoxifying agent 15 are detoxifying agents capable of reacting with the harmful components and removing the harmful components from the gas. The thing with which the reaction form of an ingredient and a harmful ingredient differs is used. For example, when the harmful component is phosphine (PH ₃ ), when copper oxide (CuO) is used as a detoxifying agent,
3CuO + 2PH ₃ → Cu ₃ P + P + 3H ₂ O
By the detoxification reaction, water (H ₂ O) is generated as a gas component that can be measured by the analyzer 16.

When basic copper carbonate (Cu (OH) ₂ .CuCO ₃ ) is used as a detoxifying agent,
3Cu (OH) ₂ · CuCO ₃ + 4PH ₃
→ 2Cu ₃ P + 3CO ₂ + 9H ₂ O + 2P
By this detoxification reaction, water and carbon dioxide (CO ₂ ) are generated as gas components that can be measured by the analyzer 16. Similarly, when the detoxifying agent is copper hydroxide, water is generated as a gas component that can be measured by the analyzer 16, and when the detoxifying agent is copper nitrate, nitrogen oxide (NOx) is generated.

  Therefore, when the harmful component to be removed is phosphine, by using copper oxide and basic copper carbonate as the main detoxifying agent 14 and the sub-detoxifying agent 15, the amount of carbon dioxide in the processing gas can be increased or decreased. By monitoring, it is possible to determine the breakthrough of the main detoxifying agent 14, and even with other combinations of copper hydroxide, copper nitrate and basic copper carbonate, the main detoxifying agent 14 depends on the amount of carbon dioxide produced. The breakthrough can be determined.

  When copper oxide, copper hydroxide or copper nitrate is used in combination with basic copper carbonate, which one should be used as the main detoxifying agent should be set arbitrarily in consideration of cost, detoxifying performance, etc. Can do. For example, when copper oxide, copper hydroxide or copper nitrate is used as the main detoxifying agent 14 and basic copper carbonate is used as the sub-detoxifying agent 15, the main detoxifying agent 14 causes sufficient reaction with harmful components. The concentration of carbon dioxide in the processing gas is relatively low, and the main detoxifying agent 14 breaks through and the reaction between the basic copper carbonate, which is the auxiliary detoxifying agent 15, and harmful components begins. As a result, the concentration of carbon dioxide in the processing gas increases.

  On the other hand, when basic copper carbonate is used as the main remover 14 and copper oxide, copper hydroxide, or copper nitrate is used as the auxiliary remover 15, when the main remover 14 is sufficiently reacted. The concentration of carbon dioxide in the processing gas is relatively high, and when the main detoxifying agent 14 breaks through and the reaction with the auxiliary detoxifying agent 15 starts, the concentration of carbon dioxide in the processing gas decreases. Become.

  Moreover, what is necessary is just to measure the density | concentration of the nitrogen oxide in process gas, when combining a copper nitrate and another abatement agent. Further, when the concentration of harmful components in the gas to be treated is substantially constant, even the detoxifying agent that produces the same gas component, for example, water, by the detoxification reaction, is produced by the reaction with the main detoxifying agent 14. If the amount of water and the amount of water produced by the reaction with the sub-detoxifying agent 15 can be discriminated by the analyzer 16, the main removal is also performed by monitoring the change in the concentration of the same gas component in the gas to be treated. The breakthrough of the agent 14 can be detected.

  For example, as can be seen from the above reaction formula, when the same amount of phosphine is treated, the amount of water generated with basic copper carbonate is 1.5 times the amount of water generated with copper oxide. By detecting the difference, breakthrough of copper oxide or basic copper carbonate used as the main scavenger 14 can be detected.

  Even when other harmful components are removed, the tendency is basically the same. For example, in the case of volatile inorganic halides, for example, HF (hydrogen fluoride), water is treated after treatment, organometallic compounds, for example, TBA (tributylarsine). ), Isobutane is produced after the treatment, so that in the same manner as in the case of the phosphine, the respective detoxifying agents are combined, and gas components that cause a change in concentration when the main detoxifying agent 14 breaks through are analyzed by the analyzer 16. By measuring with, it is possible to detect the breakthrough of the main detoxifying agent 14 and to determine the replacement time of the detoxifying agent.

  The amount of the secondary detoxifying agent 15 filled in the detoxifying cylinder 13 is sufficient to remove harmful components when the analyzer 16 detects a change in the gas component concentration accompanying the breakthrough of the main detoxifying agent 14. What is necessary is just to set to the quantity which has, and what is necessary is just to set according to conditions, such as a harmful | toxic component density | concentration in process target gas, a processing amount, and a flow rate. The analyzer 16 may be any analyzer as long as it can measure the gas component to be analyzed in the process gas, but it is preferable to use an analyzer capable of continuous measurement.

  In addition, each detoxifying agent can be used in combination with a plurality of types of detoxifying agents as long as the analyzer 16 can measure a change in a specific gas component. It is also possible to use copper hydroxide and basic copper carbonate as the sub-detoxifying agent 15.

  In this way, the concentration of the harmless gas component generated along with the removal of the harmful component is measured, and the breakthrough of the main detoxifying agent 14 is detected based on the change in the concentration of the gas component. By determining the replacement time of the detoxifying agent, it is possible to reliably determine the replacement time of the detoxifying agent before the harmful component flows out from the detoxifying cylinder 13. In addition, it is possible to more reliably determine the replacement time of the detoxifying agent than in the case where the color change of the detecting agent is visually determined. In addition, by providing an alarm generating means in the analyzer 16, it is possible to easily and reliably know the replacement time of the detoxifying agent.

  In addition, although it is preferable to arrange the main detoxifying agent 14 and the sub-detoxifying agent 15 in a single detoxifying tube 13 as described above, the main detoxifying tube filled with the main detoxifying agent 14 is used. And a sub-detoxifying cylinder filled with the sub-detoxifying agent 15 may be arranged in series, and the analyzer 16 may be provided in the processing gas outlet portion of the sub-detoxifying cylinder.

  The experimental apparatus shown in the system diagram in FIG. 2 was used. In this experimental apparatus, a nitrogen gas container 21 that supplies nitrogen gas as a base gas and a harmful gas container 22 that supplies harmful component gas are connected via pressure controllers 23 and 23 and flow rate controllers 24 and 24. In addition, nitrogen gas containing harmful components at a preset concentration can be supplied to the buffer tank 25 at a preset flow rate.

  As the abatement cylinder 26, a stainless steel cylindrical body having an inner diameter of 160 mm and an effective filling height of 300 mm was used. The treatment gas deriving unit 27 of the detoxification cylinder 26 includes an analyzer 28 for measuring gas components generated by the reaction and a noxious component for measuring harmful components that have not been removed and have flowed out of the decontamination cylinder 26. An analyzer 29 was installed, and a recorder 30 for recording the measured values of both analyzers 28 and 29 was provided, so that the recorder 30 could check the change in the concentration of each gas component.

Example 1
The toxic gas container 22 is a phosphine container, the analyzer 28 is a Fourier transform infrared absorption photometer (MIDAC: IGA200), the toxic component analyzer 29 is a phosphine gas analyzer (Bionics: TG4000), The gas to be treated with the phosphine concentration in nitrogen adjusted to 1% was introduced into the detoxifying cylinder 26 at 12 liters per minute. In the detoxifying cylinder 26, a detoxifying agent mainly composed of copper oxide serving as a main detoxifying agent on the upstream side is 200 mm in height, and a basic copper carbonate serving as a sub-detoxifying agent is composed mainly on the downstream side. Each of the detoxifying agents was filled at a height of 100 mm to form a laminated state.

  The gas to be treated was circulated through the abatement cylinder 26, and the carbon dioxide concentration was measured by the analyzer 28 and the phosphine concentration was measured by the harmful component analyzer 29. As a result, the carbon dioxide concentration, which was 500 ppm for a while after the start of the experiment, became 1000 ppm 47 hours after the start of the experiment, 5000 ppm after 53 hours, 7000 ppm after 56 hours, and then the concentration of about 7000 ppm continued. The toxic component analyzer 29 did not detect phosphine until 59 hours after the start of the experiment, but it was detected 59 hours later, and the concentration gradually increased, and reached an allowable concentration of 0.3 ppm after 60.5 hours. .

  From this experimental result, it can be seen that the copper oxide as the main scavenger approached breakthrough in about 47 hours and broke through after 56 hours. Moreover, it turns out that breakthrough approached 59 hours after the basic copper carbonate which is a sub-detoxifying agent, and broke through after 60.5 hours. Therefore, by replacing 56 hours after the time when the carbon dioxide concentration in the processing gas deriving unit 27 reaches 7000 ppm with the replacement timing of the main detoxifying agent, the detoxifying agent is replaced with a margin of about 3 hours. It can be seen that harmful components can be reliably prevented from flowing out.

  It should be noted that in actual device management, by setting so that the time when the carbon dioxide concentration reaches about 5000 ppm is determined as the time for replacement of the harmful agent before the main harmful agent completely breaks through. In addition, the outflow of harmful components to the outside can be prevented more reliably.

Example 2
A removal agent mainly composed of basic copper carbonate as a main removal agent on the upstream side of the removal tube 26 at a height of 200 mm and a removal agent containing copper oxide as a subsidiary removal agent as a main component on the downstream side. Each of the harmful agents was filled at a height of 100 mm to form a laminated state. The experiment was conducted under the same conditions as in Example 1 except for this.

  As a result, the carbon dioxide concentration measured by the analyzer 28 was 7000 ppm in less than 1 hour from the start of the experiment, and was a constant concentration of approximately 7000 ppm for a while thereafter. The carbon dioxide concentration gradually decreased from 43 hours after the start of the experiment, and became 50 ppm or less after 50 hours, and thereafter became substantially constant at 500 ppm or less. In the harmful component analyzer 29, phosphine was detected 61 hours after the start of the experiment and reached an allowable concentration of 0.3 ppm after 63 hours. Therefore, it can be determined that the main scavenger has passed through in about 50 hours.

Example 3
An abatement agent mainly composed of copper hydroxide as a main disinfectant on the upstream side of the disinfecting cylinder 26 at a height of 200 mm, and a disinfectant mainly composed of copper oxide as a sub-disinfectant on the downstream side Each of the agents was filled at a height of 100 mm to form a laminated state. The experiment was conducted under the same conditions as in Example 1 except for this.

  As a result, the water concentration (relative humidity at 25 ° C.) measured by the analyzer 28 gradually increased from the start of the experiment, reached 90% after 10 hours, and then remained substantially constant until 60 hours. After 60 hours, the water concentration gradually decreased and became 65% or less after 65 hours. The phosphine concentration measured by the harmful component analyzer 29 reached an allowable concentration of 0.3 ppm 70 hours after the start of the experiment. Therefore, it can be determined that the main scavenger has passed through in about 65 hours.

It is a schematic system diagram of the abatement apparatus showing an embodiment of the present invention. It is a systematic diagram of the experimental apparatus used in the Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Gas introduction part, 12 ... Processing gas derivation | leading-out part, 13 ... Detoxification cylinder, 14 ... Main detoxifying agent, 15 ... Sub-detoxifying agent, 16 ... Analyzer

Claims (5)

  In a detoxification apparatus that introduces a gas containing harmful components into a detoxification cylinder filled with a detoxifying agent and performs the removal process of the detrimental components, as the detoxifying agent, the main reaction having a different reaction form with the harmful components Using a harmful agent and a sub-detoxifying agent, disposing the sub-detoxifying agent on the downstream side in the gas flow direction with respect to the main detoxifying agent, and deriving the gas after the removal of the harmful components A detoxifying device, characterized in that a gas component measuring means for measuring a gas component generated by a reaction between the main detoxifying agent or auxiliary detoxifying agent and the detrimental component is provided in a processing gas deriving unit.   The gas component measuring means measures a gas component that is generated by a reaction between the sub-detoxifying agent and the harmful component and that is not generated by a reaction between the main detoxifying agent and the harmful component, or a small amount is generated. The abatement apparatus according to claim 1.   The gas component measuring means measures a gas component that is generated by a reaction between the main harmful agent and the harmful component and is not produced by a reaction between the auxiliary harmful agent and the harmful component, or a production amount is small. The abatement apparatus according to claim 1.   3. The method for managing an abatement apparatus according to claim 2, wherein the time when the concentration of the gas component to be measured is increased is determined as the replacement timing of the detoxifying agent.   The method for managing an abatement apparatus according to claim 3, wherein the time when the concentration of the gas component to be measured is lowered is determined as a replacement period for the detoxifying agent.

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