Exhaust Gas Treatment Equipment

Abstract

To provide an exhaust gas treatment facility that can operate stably for a long time and extend the filter replacement life.SOLUTION: An exhaust gas treatment facility 10 comprises: detoxification devices 11, 21 which perform a detoxification treatment on harmful components of exhaust gases; a filter unit 31 which separates powder contained in the exhaust gas emitted from the detoxification devices 11, 21; an exhaust gas pipeline L1 from the detoxification devices 11, 21 to the filter unit 31; and atmosphere suction valves 12, 22 at the outlets of the detoxification devices 11, 21. A control unit that controls the opening and closing of the atmosphere suction valves 12, 22 controls the atmosphere suction valves 12, 22 in the closing direction when an increase in the differential pressure between the upstream side and the downstream side of the filter unit 31 is detected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an exhaust gas treatment facility, and more particularly to a treatment facility for exhaust gas containing harmful components discharged from various electronic device manufacturing apparatuses such as semiconductor manufacturing apparatuses. [Background technology]

[0002] Various process gases and cleaning gases are used in various electronic device manufacturing equipment such as semiconductors. Since the process gases and cleaning gases (hereinafter referred to as exhaust gases) contain harmful components, they are sent to a detoxification device via a pump and detoxified. Powder generated during the detoxification process is separated and removed before being exhausted to the outside.

[0003] In such exhaust gas treatment equipment, there have been proposals to install multiple filter units that separate and remove powder, and to ensure stable operation by switching between the filters in use and the filters that require maintenance (e.g., Patent Document 1), as well as to use metal piping with an epoxy resin baked-on coating on the inner surface of the piping to prevent powder from accumulating on the exhaust gas piping from the abatement device to the filter units (e.g., Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-21315 A [Patent Document 2] JP 2016-017678 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a demand for exhaust gas treatment equipment that can prevent filter blockage (clogging) and extend the filter replacement life without installing multiple filter units, such as the exhaust gas treatment equipment shown in Patent Document 1.

[0006] Therefore, an object of the present invention is to provide an exhaust gas treatment facility that can operate stably for a long period of time and that can extend the filter replacement life. [Means for solving the problem]

[0007] In order to solve the above problems, the first aspect of the present invention provides an exhaust gas treatment facility comprising a detoxification device that renders harmful components in exhaust gas harmless, a filter unit that separates powder contained in the exhaust gas discharged from the detoxification device, and exhaust gas piping leading from the detoxification device to the filter unit, wherein an atmospheric intake valve is provided at the outlet of the detoxification device, and a control unit that controls the opening and closing of the atmospheric intake valve controls the atmospheric intake valve in the direction of closing when it detects an increase in the differential pressure between the upstream and downstream sides of the filter unit.

[0008] In addition, a second aspect of the present invention is an exhaust gas treatment facility comprising a detoxification device for neutralizing harmful components in exhaust gas, a filter unit for separating powder contained in the exhaust gas discharged from the detoxification device, and exhaust gas piping leading from the detoxification device to the filter unit, wherein an atmospheric intake valve is provided at the outlet of the detoxification device, and a control unit for controlling the opening and closing of the atmospheric intake valve receives a gas usage signal from a manufacturing device that outputs exhaust gas to the detoxification device, and controls the atmospheric intake valve in the direction of closing when the signal does not indicate that a gas that generates powder is being used during the detoxification treatment of the detoxification device.

[0009] Furthermore, the third invention of the present invention is an exhaust gas treatment facility comprising a detoxification device for detoxifying harmful components in exhaust gas, a filter unit for separating powder contained in the exhaust gas discharged from the detoxification device, and an exhaust gas piping leading from the detoxification device to the filter unit, wherein an atmospheric intake valve is provided at the outlet of the detoxification device, and a control unit for controlling the opening and closing of the atmospheric intake valve controls the atmospheric intake valve in the direction of closing when it detects that the detoxification device is not in a combustion mode that generates powder during detoxification treatment.

[0010] In addition, an air introduction valve for adjusting the transport speed, which introduces air to adjust the transport speed, is provided at an end of the exhaust gas piping opposite to the end connected to the filter unit, and the control unit controls the air introduction valve for adjusting the transport speed in an opening direction when it detects a decrease in the differential pressure between the upstream side and the downstream side of the filter unit. The decomposition device may further include a decomposition section that thermally decomposes harmful components in the exhaust gas, a tank section that is provided below the decomposition section and that stores cooling water, and a scrubber section that is provided above the tank section and that sprays cleaning water, Furthermore, a plurality of the abatement devices may be provided. Effect of the Invention

[0011] According to the first invention, when an increase in the differential pressure between the upstream and downstream sides of the filter unit is detected, the air intake valve is controlled in the direction of closing, thereby reducing the overall ventilation air volume, preventing powder from re-adhering to the filter unit, and restoring the differential pressure. By restoring the differential pressure in this way, it is possible to extend the period until the differential pressure reaches the guideline for filter replacement.

[0012] Furthermore, according to the second and third inventions, the load state of the generated powder is constantly recognized, and the differential pressure is restored when no powder is generated, thereby enabling more stable operation and extending the life of parts before replacement.

[0013] Furthermore, by providing an air introduction valve for adjusting the transport speed, the powder transport speed in the exhaust gas piping can be constantly ensured, enabling stable operation. [Brief description of the drawings]

[0014] [Figure 1] 1 is an explanatory diagram showing an example of an exhaust gas treatment facility according to the present invention; [Diagram 2] 4 is a graph showing the change in filter differential pressure ΔP over the number of days in continuous operation according to one embodiment of the exhaust gas treatment equipment of the present invention and in normal continuous operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] 1 is an explanatory diagram showing one embodiment (example) of an exhaust gas treatment facility of the present invention. The exhaust gas treatment facility 10 in this embodiment is generally composed of a plurality of detoxification devices 11, 21 that perform detoxification of gas discharged from various electronic device manufacturing equipment 1 such as semiconductor manufacturing equipment via a dry pump 2, a filter unit 31 that separates powder contained in the exhaust gas discharged from the detoxification devices 11, 21, and an exhaust gas pipe L1 that runs from the detoxification devices 11, 21 to the filter unit 31.

[0016] The electronic device manufacturing apparatus 1 is, for example, a process chamber for manufacturing semiconductors, and various gases are used depending on the type and process of film formation, and exhaust gases corresponding to the gases are discharged. These gases discharged from the electronic device manufacturing apparatus 1 are sucked by the dry pump 2 and sent to the decontamination apparatus 11.

[0017] The abatement device 11 is of the so-called water-cooled thermal decomposition type, and includes a decomposition section 11a, a tank section 11b, and a scrubber section 11c. The decomposition section 11a thermally decomposes harmful components in the exhaust gas, and has a double-cylinder structure consisting of an inner cylinder and an outer cylinder, and includes a burner inside the inner cylinder. A fuel supply pipe (not shown) and a combustion-supporting fluid supply pipe (not shown) are arranged in the burner, and when the fuel supplied from the fuel supply pipe is mixed with the combustion-supporting fluid supplied from the combustion-supporting fluid supply pipe and combusted, the exhaust gas supplied from the dry pump 2 is thermally decomposed.

[0018] The exhaust gas treated in the decomposition section 11a and the powder generated during the treatment are discharged to the tank section 11b provided below the decomposition section 11a. The tank section 11b is a cooling water tank in which cooling water is stored up to an intermediate height in a sealed state, and is provided with an exhaust port at the top to which the scrubber section 11c described below is connected. In the tank section 11b, the gas discharged from the decomposition section 11a is cooled by contacting with the cooling water, and a part of the powder (secondary product) is captured by the cooling water. Although not shown in the figure, the tank section 11b is provided with a water supply path and a drainage path for introducing new cooling water to replace the water while keeping the amount of cooling water stored constant.

[0019] The scrubber section 11c is provided on the upper part of the tank section 11b, and is filled with a filler material and has a spray nozzle above the filler material. In the scrubber section 11c, impurities in the gas cooled by the cooling water in the tank section 11b are captured by the filler material, and then the gas is washed with cleaning water sprayed from the spray nozzle to remove water-soluble components.

[0020] The exhaust gas discharged from the scrubber section 11c contains a relative humidity of almost 100% and a small amount of mist due to water spraying from the spray nozzle, and some powder still remains. If powder with a high moisture content or moisture mist is entrained in the exhaust gas, the adhesion force on the filter surface of the filter unit 31 described later increases, and it may be difficult to remove the powder from the filter surface even by backwashing. For this reason, an air intake valve 12 for drawing in air for drying is provided at the outlet (rear stage of the abatement device) of the scrubber section 11c before joining the exhaust gas pipe L1. The air intake valve 12 is a control valve whose opening can be adjusted to adjust the flow rate of the air to be introduced. The air introduced from the air intake valve 12 is used not only for drying as described above, but also for transporting the powder in the exhaust gas pipe L1.

[0021] The abatement device 21 has the same configuration as the abatement device 11, and includes a decomposition section 21a, a tank section 21b, and a scrubber section 21c, and an air intake valve 22 is provided at the outlet of the scrubber section 21c.

[0022] A plurality of bag filters 31a are provided inside the filter unit 31. The exhaust gas introduced into the filter unit 31 from the exhaust gas piping L1 passes through the bag filter 31a from the primary side to the secondary side, and powder and the like contained in the exhaust gas adheres to and accumulates on the primary side surface of the bag filter 31a. The exhaust gas that has passed through the bag filter 31a is discharged to the outside of the exhaust gas treatment facility 10 by the exhaust pump 3.

[0023] In addition, in order to backwash the powder and other materials adhering to the bag filter 31a, the backwash valve 31b is constantly opened and closed at regular intervals, and jetted air is blown from the secondary side to the primary side of the bag filter 31a, causing the powder and other materials adhering to the primary side surface of the bag filter 31a to detach and fall into the powder discharge section (hopper) 31c.

[0024] In the exhaust gas treatment equipment 10 of this embodiment, a control unit (not shown) detects the difference in pressure (filter differential pressure ΔP) measured by a pressure gauge P1 on the upstream side and a pressure gauge P2 on the downstream side of the filter unit 31. As exhaust gas treatment continues in the exhaust gas treatment equipment 10, clogging of the bag filter 31a progresses and the filter differential pressure ΔP gradually increases, and when it reaches 1.0 kPa, it is determined that it is time to replace the filter.

[0025] Further, at the end of the exhaust gas pipe L1 opposite to the end connected to the filter unit 31, an air introduction valve 41 for adjusting the transfer speed is provided, which introduces air in order to adjust the transfer speed.

[0026] Here, if the amount of ventilation air from the exhaust gas pipe L1 to the filter unit 31 is large, a phenomenon occurs in which the adhering powder removed by backwashing adheres again to the primary side surface of the bag filter 31a.

[0027] Therefore, in the exhaust gas treatment facility 10 in this embodiment, when the control unit detects an increase in the filter differential pressure ΔP during continuous operation of the exhaust gas treatment (for example, when an increase of 0.9 to 1.0 kPa is detected), the control unit automatically controls the opening of the atmospheric intake valves 12, 22 provided at the rear of the detoxification devices 11, 21 in a direction to temporarily reduce the opening. In this way, by reducing the opening of the atmospheric intake valves 12, 22, the overall ventilation air volume is reduced, reattachment to the primary side surface of the bag filter 31a is prevented, and the differential pressure is restored. In addition, the atmospheric intake valves 12, 22 whose opening has been reduced may be controlled by a timer to return to their original opening after, for example, 10 to 60 minutes have elapsed, depending on the number of bag filters 31a. At this time, if the differential pressure recovery cannot be confirmed, the opening of the atmospheric intake valves 12, 22 may be controlled again in a direction to reduce the opening.

[0028] 2 is a graph showing the change in filter differential pressure ΔP over time in normal continuous operation and in the case where control is performed with the addition of a differential pressure recovery function according to the embodiment of the present invention described above. In the case of normal continuous operation, as shown by the black triangles, the filter differential pressure reached the replacement guideline of 1.0 kPa in about 240 days. In the case of the embodiment of the present invention, as shown by the black circles, it took about 330 days to reach the filter differential pressure that is the replacement guideline, enabling stable operation and an extended part replacement lifespan.

[0029] Next, a modified example (Modification 1) of the control of the exhaust gas treatment facility 10 of the present invention will be described. In the electronic device manufacturing apparatus 1, various gases are used depending on the type and process, and exhaust gas corresponding to the gas is discharged. In the process steps for manufacturing semiconductors and liquid crystal panels, special gases such as silane gas (SiH4) and tungsten hexafluoride (WF6) are used as process gases. When these flammable special gases are treated by the abatement device 11, powder (secondary product) is generated.

[0030] On the other hand, when a persistent gas such as nitrogen trifluoride (NF3) used in the cleaning process is treated by the detoxification device 11, the generation of powder is slight.

[0031] A gas usage signal indicating what gas is being used in what process is transmitted from the electronic device manufacturing apparatus 1 to the control unit of the exhaust gas treatment facility 10. Examples of the gas usage signal include a signal (DEPO signal) indicating that a film formation process (process step) that generates powder is being performed in the decontamination device 11, a signal (CLN signal) indicating that a cleaning process is being performed, and the like.

[0032] In the event that powder is generated in the abatement device 11, the load caused by the powder generation will be such that differential pressure recovery control as in the above embodiment will have little effect. However, if the control unit confirms that no powder is being generated, the opening of the atmospheric intake valves 12, 22 can be automatically controlled to reduce, thereby reducing the overall ventilation air volume and achieving differential pressure recovery.

[0033] The control unit confirms that no powder is being generated when, for example, both the DEPO signal and the CLN signal are received and neither signal is input. Also, if only the CLN signal is received, the CLN signal input is sufficient since it indicates that at least a large amount of powder is not being generated and the load is light (this may be considered to be a case where the signal is not using the gas that generates the powder of the present invention).

[0034] In the embodiment, when an increase in the filter differential pressure ΔP is detected, the opening of the atmosphere intake valves 12, 22 is controlled, but as time passes and the filter becomes increasingly clogged, it becomes difficult to remove the powder by backwashing, and in some cases, sufficient effects are not obtained. In the first modification, the steady load state of the generated powder is recognized by the input signal from the electronic device manufacturing equipment 1, and then differential pressure recovery control is added, making it possible to further stabilize operation and extend the life of parts replacement.

[0035] Note that many models of abatement devices 11, 21 are capable of switching the combustion mode in order to optimize the operating conditions (combustion mode) from the viewpoint of energy saving, based on a gas usage signal from electronic device manufacturing equipment 1. Therefore, instead of controlling based on a gas usage signal from electronic device manufacturing equipment 1 as in variant 1, as variant 2, it is also possible to control the opening degree of atmosphere intake valves 12, 22 by the control unit based on the combustion mode of the abatement device.

[0036] As a combustion mode, for example, there is an idle mode in which only a small ignition burner is on (fuel consumption of about 1 L / min) when the gas to be treated is not flowing, and when the gas to be treated starts to flow, the mode switches to a low energy mode or a high energy mode.

[0037] The low-energy mode is a mode used when treating flammable gases such as silane gas (SiH4) or tungsten hexafluoride (WF6), which can be detoxified using 60-70% of the fuel used.

[0038] The high-energy mode is a mode used when treating, for example, difficult-to-decompose gases such as nitrogen trifluoride (NF3) that can only be treated using 100% of the fuel.

[0039] Therefore, in the idle mode and high energy mode, no powder is generated during treatment by the abatement device (in the high energy mode, a small amount of powder is generated, as in the case of the CLN signal input in the first modification, but this may be considered as a mode that is not a combustion mode that generates powder according to the present invention). Therefore, as a second modification, when the control unit confirms that no powder is being generated based on the combustion mode of the abatement device, the opening of the atmospheric intake valves 12, 22 may be automatically controlled in a direction to reduce, thereby reducing the overall ventilation air volume and attempting to restore the differential pressure.

[0040] Furthermore, in any of the embodiment, variant 1, and variant 2, when both decontamination devices 11, 21 are operating, the powder transport speed in the exhaust gas piping L1 is sufficient. However, if either of them stops, the powder transport speed in the exhaust gas piping L1 decreases, and there is a risk of powder accumulating on the exhaust gas piping L1.

[0041] In the case of two abatement devices and one filter unit, the filter differential pressure ΔP during normal operation is 0.6-0.8 kPa. If one of the abatement devices stops, the filter differential pressure ΔP drops to about 0.3 kPa.

[0042] In this way, when the control unit detects that the filter differential pressure ΔP has dropped to a level where it is determined that the powder transport speed in the exhaust gas piping L1 is not being obtained sufficiently, it is preferable to open the atmosphere introduction valve 41 for adjusting the transport speed in the exhaust gas piping L1, and return the filter differential pressure ΔP to approximately 0.6 kPa to ensure the transport speed.

[0043] Incidentally, the degree of decrease in the filter differential pressure ΔP at which the transport speed adjusting atmosphere introduction valve 41 should be opened may be preset based on the number of abatement devices, filter units, etc.

[0044] Table 1 below shows examples of the air flow rate at each location of the exhaust gas treatment equipment 10 during normal operation and during differential pressure recovery control in Example 1 and Modifications 1 and 2, when the filter differential pressure ΔP drops and the atmospheric intake valve 41 for adjusting the conveying speed is opened.

[0045] Q1 is the flow rate of exhaust gas after abatement treatment in the abatement device 11, Q2 is the flow rate of air taken in through the atmospheric intake valve 12, Q3 is the flow rate of exhaust gas after abatement treatment in the abatement device 21, Q4 is the flow rate of air taken in through the atmospheric intake valve 22, and Q5 is the flow rate of air taken in through the atmospheric introduction valve 41 for adjusting the transport speed.

[0046] [Table 1]

[0047] In the above embodiment, the exhaust gas treatment equipment has two detoxifiers and one filter unit, but the number of each is not particularly limited. The detoxifier is not limited to the water-cooled thermal decomposition type, and any known type capable of detoxifying harmful components in exhaust gas, such as a heater type or a plasma type, may be used. [Explanation of symbols]

[0048] 1...electronic device manufacturing equipment, 2...dry pump, 3...exhaust pump, 10...exhaust gas treatment equipment, 11, 21...abatement device, 11a, 21a...decomposition section, 11b, 21b...tank section, 11c, 21c...scrubber section, 12, 22...atmospheric intake valve, 31...filter unit, 31a...bag filter, 31b...backwash valve, 31c...powder discharge section, 41...atmospheric intake valve for adjusting conveying speed

Claims

1. An exhaust gas treatment facility including a detoxification device that detoxifies harmful components in exhaust gas, a filter unit that separates powder contained in the exhaust gas discharged from the detoxification device, and an exhaust gas piping that runs from the detoxification device to the filter unit, An atmosphere intake valve is provided at an outlet of the abatement device, The control unit which controls the opening and closing of the atmospheric intake valve controls the atmospheric intake valve to close when it detects an increase in the differential pressure between the upstream and downstream sides of the filter unit.

2. An exhaust gas treatment facility including a detoxification device that detoxifies harmful components in exhaust gas, a filter unit that separates powder contained in the exhaust gas discharged from the detoxification device, and an exhaust gas piping that runs from the detoxification device to the filter unit, An atmosphere intake valve is provided at an outlet of the abatement device, The control unit which controls the opening and closing of the atmospheric intake valve receives a gas usage signal from a manufacturing device which outputs exhaust gas to the decontamination device, and controls the atmospheric intake valve in the direction of closing if the signal does not indicate that a gas which generates powder is being used during the decontamination process.

3. An exhaust gas treatment facility including a detoxification device that detoxifies harmful components in exhaust gas, a filter unit that separates powder contained in the exhaust gas discharged from the detoxification device, and an exhaust gas piping that runs from the detoxification device to the filter unit, An atmosphere intake valve is provided at an outlet of the abatement device, An exhaust gas treatment facility characterized in that a control unit that controls the opening and closing of the atmospheric intake valve controls the atmospheric intake valve to close when it detects that the combustion mode during the detoxification process of the decontamination device is not one that generates powder.

4. an air introduction valve for adjusting a conveying speed, which introduces air in order to adjust a conveying speed, is provided at an end of the exhaust gas pipe opposite to the end connected to the filter unit; 4. The exhaust gas treatment facility according to claim 1, wherein the control unit controls the transport speed adjusting atmospheric intake valve in an opening direction when it detects a decrease in the differential pressure between the upstream side and the downstream side of the filter unit.

5. The exhaust gas treatment equipment as described in claim 4, characterized in that the abatement device comprises a decomposition section which heats and decomposes harmful components in the exhaust gas, a tank section provided at the bottom of the decomposition section which stores cooling water, and a scrubber section provided at the top of the tank section which sprays cleaning water.

6. 6. The exhaust gas treatment facility according to claim 5, wherein a plurality of the abatement devices are provided.

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