Abatement device, deposit removing means, and deposit removing method

Abstract

produced during abatement of exhaust gas, the deposit removing means comprising a reservoir (P3) for storing liquid, a gas supply part (P1) for supplying pressurized gas to the reservoir, and a valve

Description

[Technical Field]

[0001] This invention relates to a pest control device, a piling removal mechanism for removing pilings accumulated in the pest control device, and a piling removal method for removing pilings accumulated in the pest control device. [Previous Technology]

[0002] The exhaust gases emitted from semiconductor manufacturing equipment and the like contain harmful components, so it is necessary to use a decontamination device to render the exhaust gases harmless. When the exhaust gases undergo an oxidation reaction, oxides accumulate in the decontamination device, so these accumulations must be removed periodically.

[0003] For example, Patent Document 1 describes a pest control device comprising: a nozzle for a treated gas, which has a gas inlet outlet disposed on the top surface of a combustion chamber to guide the treated gas into the combustion chamber; a cleaning head that moves deposits adhering to the nozzle up and down within the nozzle and discharges them from the gas inlet outlet into the combustion chamber for removal; a scraper disposed in the combustion chamber facing the top surface and rotatably horizontally to remove deposits adhering to the top surface of the combustion chamber; and a drive device that drives the cleaning head and scraper in a manner that prevents interference between the cleaning head and the scraper. According to this configuration, deposits adhering to the inner wall of the treated gas passage and the wall of the combustion chamber can be easily and quickly scraped off and removed. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent No. 6777472 [Summary of the Invention]

[0005] [The problem the invention aims to solve]

[0006] However, since Patent Document 1 is constructed by scraping off the deposits with a scraper, it cannot remove deposits attached to areas that the scraper cannot physically reach. Therefore, Patent Document 1 has room for improvement in terms of more efficient removal of deposits.

[0007] This invention was made in view of the above-mentioned situation, and its purpose is to efficiently remove deposits adhering to the inside of the pest control device. [Technical Means for Solving the Problem]

[0008] To achieve the above objective, one embodiment of the present invention is a pest control device, which includes a deposit removal mechanism for removing deposits generated during the removal of exhaust gases, and is characterized in that the deposit removal mechanism includes: a storage section for storing liquid; a gas supply section for supplying pressurized gas to the storage section; and a valve for spraying a mixture of the liquid stored in the storage section and the gas supplied by the gas supply section.

[0009] Furthermore, in the above configuration, it is preferable to further include: a pressure sensor that detects the pressure at the inlet of the discharged gas; and a control unit that controls the opening and closing of the valve; wherein the control unit controls the valve by opening it based on the pressure at the inlet exceeding a threshold.

[0010] Furthermore, in the above configuration, it is preferable that the control unit maintains the valve open for a period of time up to the elapsed period after the valve is opened.

[0011] Furthermore, in the above configuration, it is preferable that the specific time is set to a time longer than the time during which the liquid stored in the storage section is completely sprayed.

[0012] Furthermore, in the above configuration, it is preferable that the control unit controls the valve to be in a closed state during the period when the above-mentioned purifying device purifies the above-discharged gas.

[0013] To achieve the above objective, another aspect of the present invention is a deposit removal mechanism, which is applied to a pest control device for removing harmful gases and for removing deposits generated during the removal of harmful gases. The deposit removal mechanism is characterized in that it comprises: a storage section for storing liquid; a gas supply section for supplying pressurized gas to the storage section; and a valve for spraying a mixture of the liquid stored in the storage section and the gas supplied by the gas supply section.

[0014] To achieve the above objective, another aspect of the present invention is a method for removing deposits, which is a method for removing deposits generated by a decontamination device for removing exhaust gases, characterized in that it includes: a first step of storing a liquid; a second step of supplying pressurized gas to the liquid stored in the first step; and a third step of spraying the mixture of the liquid and the gas generated in the second step onto the deposits to remove the deposits. [Effects of the Invention]

[0015] According to the present invention, deposits adhering to the pest control device can be removed efficiently. Furthermore, the problems, configurations, and effects other than those described above will become clear from the following description of embodiments.

Implementation Method

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0018] Figure 1 is an overall configuration diagram of the exhaust gas treatment system of the pest control device of the present invention. The exhaust gas treatment system shown in Figure 1 is used, for example, to render the exhaust gas (process gas, cleaning gas) discharged from the process chamber 1 of a semiconductor manufacturing apparatus, a flat panel display manufacturing apparatus, a solar panel manufacturing apparatus, etc., harmless.

[0019] In the process chamber 1, CVD (Chemical Vapor Deposition) processing or etching processing (hereinafter referred to as process processing) using chemical vapor phase reaction to form films is performed, and various gases are used in the process chamber 1. Such gases include, for example, silane (SiH4), NH3, H2, etc., which are film-forming materials for semiconductor devices, liquid crystal panels, and solar cells, or inert gases such as gaseous fluorides such as NF3, CF4, C2F6, SF6, CHF3, CF6, etc., and nitrogen (N2), which are used as cleaning gases when cleaning with plasma in the process chamber of a plasma CVD device.

[0020] To perform vacuuming to remove the harmful exhaust gas, a turbomolecular pump (TMP) 2, as an example of a vacuum pump, is connected to the process chamber 1. Further downstream of the turbomolecular pump 2, a dry pump (DRP) 3 is connected in series with the turbomolecular pump 2. When removing the exhaust gas from the process chamber 1, the dry pump 3 first performs a certain degree of vacuuming at the start of operation, and then the turbomolecular pump 2 performs vacuuming to the required low pressure. Alternatively, a rotary pump can be used instead of the dry pump 3, or the dry pump 3 itself can be omitted depending on the specifications of the exhaust gas treatment system.

[0021] The harmful exhaust gas discharged from the self-made process chamber 1 via the turbomolecular pump 2 and the dry vacuum pump 3 is combusted and decomposed by the purifying device 4, and then electrostatically collected by the electrostatic dust collection device 5 before reaching the central scrubber 6. At this time, the exhaust gas is slightly depressurized by the central scrubber 6 and guided into the purifying device 4 and the electrostatic dust collection device 5. Alternatively, the purifying device 4 and the electrostatic dust collection device 5 may be configured as a single device.

[0022] Next, the decontamination device 4 in each of the devices constituting the exhaust gas treatment system will be described in detail. Since the configurations of the other devices are well known, detailed descriptions are omitted. FIG2 is a configuration diagram showing the details of the decontamination device 4 according to an embodiment of the present invention. The decontamination device 4 shown in FIG2 is a combustion-type decontamination device that renders the exhaust gas containing the aforementioned harmful components harmless through combustion or thermal decomposition.

[0023] The pest control device 4 includes: a body 12 having a combustion chamber 11 through which exhaust gas is introduced; an intake nozzle 16 serving as a gas passage for introducing exhaust gas into the combustion chamber 11; a main burner 13 forming a flame on the side of the combustion chamber 11; an auxiliary burner 15 forming a flame near the outlet of the intake nozzle 16; an igniter 14 forming the ignition source required for the main burner 13 and the auxiliary burner 15; a deposit removal mechanism 40 (see Figure 3) for removing deposits 17 such as silicon dioxide (SiO2) accumulated near the outlet of the intake nozzle 16; a pressure sensor 19 disposed in the intake nozzle 16 for detecting the pressure of the introduced exhaust gas; and a controller 50 for controlling the pest control device 4.

[0024] The main body 12 has a first cylindrical wall 21 that is generally cylindrical, and a second cylindrical wall 22 that is also generally cylindrical and disposed outside the first cylindrical wall 21. The upper surfaces of the first cylindrical wall 21 and the second cylindrical wall 22 are closed by an air inlet head 23, and the lower surfaces are closed by a bottom wall (not shown). Furthermore, the internal space of the first cylindrical wall 21 is a combustion chamber 11, that is, a combustion gas chamber 24 in which combustible fuel 25 and air 26 are introduced into the annular space between the first cylindrical wall 21 and the second cylindrical wall 22. In addition, the first cylindrical wall 21 and the second cylindrical wall 22 are not necessarily cylindrical.

[0025] The main burner 13 is disposed in the combustion gas chamber 24. The main burner 13 sprays a mixture 27 of combustible fuel 25 and air 26 toward the combustion chamber 11 through a plurality of nozzles 21a disposed on the first cylinder wall 21. Therefore, a first combustion-supporting gas supply nozzle 28 for supplying combustible fuel 25 to the combustion gas chamber 24 and a second combustion-supporting gas supply nozzle 29 for supplying air 26 to the combustion gas chamber 24 are disposed on the second cylinder wall 22.

[0026] The auxiliary burner 15 is disposed at the air inlet head 23. More specifically, the auxiliary burner 15 is disposed near the outlet of the air inlet nozzle 16. A third combustion-supporting gas supply nozzle 30 is disposed midway through the air inlet nozzle 16, through which combustible fuel 25 and oxygen (or air 26) are supplied to the air inlet nozzle 16, and the auxiliary burner 15 sprays the mixture of combustible fuel 25 and oxygen (or air 26) toward the combustion chamber 11, and exhausts the combusted gas. In addition, in this embodiment, the auxiliary burner 15 performs combustion at a higher temperature than the main burner 13, which can effectively remove harmful gases (such as CF4).

[0027] Furthermore, an auxiliary nozzle 31 is provided at the intake nozzle 16, through which a mixed fluid of water and nitrogen sprayed by the deposit removal mechanism 40, which will be described in detail later, flows. In addition, the auxiliary nozzle 31 is installed at the intake nozzle 16 at an angle such that the mixed fluid sprayed from the auxiliary nozzle 31 collides with the approximately central portion of the deposit 17.

[0028] Ignition device 14 is disposed at air intake head 23. Ignition device 14 sprays a mixture of combustible fuel 25 and air 26 (or oxygen) from above the combustion chamber 11 toward the interior of the combustion chamber 11 to generate ignition.

[0029] During the pest control process, a film-like deposit 17 accumulates near the outlet of the air intake nozzle 16. In order to remove the deposit 17, the pest control device 4 is equipped with a deposit removal mechanism 40.

[0030] Figure 3 is a structural diagram of the buildup removal mechanism 40 shown in Figure 2. As shown in Figure 3, the buildup removal mechanism 40 includes: a nitrogen pipe P1 serving as a gas supply unit, through which nitrogen flows; a water pipe P2 serving as a water supply unit, through which water flows; a storage pipe P3 serving as a storage unit, through which a mixture of water and nitrogen is stored; an exhaust pipe P4; an injection pipe P5 used to spray the mixture towards the auxiliary nozzle 31 of the pest control device 4; check valves 43, 44, and 45; and three-way valves 41 and 42. Furthermore, the opening and closing of the three-way valves 41 and 42 are controlled by a controller 50 (see Figure 2).

[0031] Nitrogen gas is supplied to nitrogen pipe P1 at a pressure of, for example, 0.6 MPa and stored in storage pipe P3. Water is supplied to water pipe P2 at a pressure of, for example, 0.3 MPa and stored in storage pipe P3. The mixture of water and nitrogen gas stored in storage pipe P3 flows through injection pipe P5 and is sprayed into combustion chamber 11 through auxiliary nozzle 31. Furthermore, the air in storage pipe P3 is exhausted to the atmosphere through exhaust pipe P4.

[0032] Here, the nitrogen and water are not adjusted to the pressure mentioned above for supplying to the deposit removal mechanism 40, but are directly supplied from the nitrogen or water that is permanently located in the factory where the pest control device 4 is installed. That is, the nitrogen or water is not pressurized or depressurized specifically for the pest control device 4.

[0033] In this embodiment, the volume of water to be stored is relatively small, for example, about a few cc. Therefore, the storage piping P3 also serves as a storage unit.

[0034] Although not shown in the figure, the controller 50 is configured to include: hardware, which includes a CPU (Central Processing Unit) for performing various calculations, a memory device such as ROM (Read Only Memory) or HDD (Hard Disc Drive) for storing programs used to execute the CPU's calculations, RAM (Random Access Memory) which serves as the operating area for the CPU to execute programs, and an interface for sending and receiving data with other machines, i.e., a communication interface; and software, which is stored in the memory device and executed by the CPU. The various functions of the controller 50 are realized by the CPU loading various programs stored in the memory device into RAM and executing them.

[0035] Next, the operation of the buildup removal mechanism 40, in other words, the method for removing the buildup 17 from the buildup removal mechanism 40, will be explained. Figures 4(a) to 4(d) show the sequence of operation of the buildup removal mechanism 40. In the figures, the blacked-out ports of the three-way valves 41 and 42 indicate the closed state, and the whiteed-out ports indicate the open state.

[0036] When the controller 50 is not in the process of processing and the pressure detected by the pressure sensor 19 exceeds a certain threshold, it determines that the start condition for the operation of the deposit removal mechanism 40 is met and starts the operation of the deposit removal mechanism 40. Here, the determination of whether the process is in progress is based on the process signal from the process chamber 1 input to the controller 50.

[0037] On the other hand, when the pressure detected by the pressure sensor 19 is below a threshold during the process, the controller 50 stops the operation of the deposit removal mechanism 40. That is, the controller 50 does not spray the mixed fluid using the deposit removal mechanism 40 during the period when the purging device 4 is emitting gas for purging. In addition, the threshold is preset to the value at which the internal pressure of the air intake nozzle 16 rises and deposits 17 are generated.

[0038] When the above-mentioned start conditions are met, the controller 50 first activates the three-way valves 41 and 42 as shown in Figure 4(a). This disconnects the nitrogen piping P1 from the storage piping P3, disconnects the storage piping P3 from the injection piping P5, and connects the water piping P2, storage piping P3, and exhaust piping P4. Therefore, water flows sequentially through the water piping P2, storage piping P3, and exhaust piping P4, releasing the air in the storage piping P3 to the atmosphere.

[0039] Next, the controller 50 actuates the three-way valves 41 and 42 as shown in Figure 4(b). This connects nitrogen pipe P1 to storage pipe P3, water pipe P2 to storage pipe P3, disconnects storage pipe P3 from exhaust pipe P4, and disconnects storage pipe P3 from injection pipe P5. Therefore, the pressurized mixture of nitrogen and water is stored in storage pipe P3 (step 1, step 2).

[0040] Next, the controller 50 actuates the three-way valves 41 and 42 as shown in Figure 4(c). This connects nitrogen pipe P1 to storage pipe P3, disconnects water pipe P2 from storage pipe P3, disconnects storage pipe P3 from exhaust pipe P4, and connects storage pipe P3 to injection pipe P5. Therefore, the nitrogen-water mixture stored in storage pipe P3 flows through injection pipe P5. The nitrogen-water mixture flowing through injection pipe P5 is sprayed via auxiliary nozzle 31 towards the deposit 17 near the outlet of intake nozzle 16 (step 3).

[0041] At this time, the deposit 17 is subjected to a rapid temperature change due to the spray of water droplets, resulting in cracks due to the change in surface condition. Then, the deposit 17 is crushed and removed by the impact force of pressurized nitrogen. Furthermore, in this embodiment, the controller 50 maintains the state shown in FIG. 4(c) for a specific time. More specifically, even after the water stored in the storage pipe P3 is sprayed, it is temporarily maintained in a state of nitrogen spraying. Therefore, the cracked deposit 17 can be removed by reliably pressurized nitrogen. Here, "specific time" means, for example, about 5 seconds, but this time can be appropriately determined based on the volume of the storage pipe P3 for the stored water and nitrogen.

[0042] Furthermore, since the water stored in the storage pipe P3 is sprayed and then temporarily kept in a state of nitrogen spraying, water residue in the auxiliary nozzle 31, especially near the outlet, can be prevented. Also, since the nitrogen blows away the water droplets in the auxiliary nozzle 31, deposits can be prevented from accumulating in the auxiliary nozzle 31.

[0043] Next, the controller 50 actuates the three-way valves 41 and 42 as shown in Figure 4(d). This disconnects the nitrogen pipe P1 from the storage pipe P3, disconnects the water pipe P2 from the storage pipe P3, connects the storage pipe P3 to the exhaust pipe P4, and connects the storage pipe P3 to the injection pipe P5. Therefore, when nitrogen accumulates in the storage pipe P3, the nitrogen is released to the atmosphere through the exhaust pipe P4.

[0044] Thus, when the controller 50 is not in the process processing state and the internal pressure of the inlet nozzle 16 exceeds the threshold, it determines that the deposit 17 has accumulated, and causes the deposit removal mechanism 40 to operate as shown in Figures 4(a) to (d) to remove the deposit 17. The controller 50 repeats this operation each time the operation start condition is met.

[0045] The pest control device 4 constructed as described above can perform the following functions.

[0046] By spraying nitrogen containing water droplets onto the pile 17, a rapid temperature change can be imposed on the pile 17. This causes cracks to form in the pile 17. Furthermore, by spraying pressurized nitrogen containing water droplets onto the pile 17, the impact is increased compared to simply spraying nitrogen, which can blow away and remove the cracked pile 17. Moreover, since the cracking of the pile 17 is caused by utilizing the rapid temperature change, a small amount of water (water droplets) is sufficient to spray onto the pile 17. That is, the pile is not disintegrated by the impact force of a large amount of water, but only by spraying a small amount of water onto the high-temperature (e.g., around 800-900°C) pile 17.

[0047] Furthermore, in this embodiment, since the mixed fluid of water and nitrogen is generated using the factory's existing nitrogen system, it is not necessary to use a pressure pump or the like to make the water high pressure. Therefore, no special equipment is required to install the pest control device 4.

[0048] Furthermore, according to this embodiment, the accumulated material in the portion that cannot be scraped off by the scraper can be removed efficiently, and there is no need for a scraper to scrape off the accumulated material 17. Of course, if the accumulated material removal mechanism 40 of this embodiment and the scraper are used together, the accumulated material 17 can be removed even more effectively.

[0049] Furthermore, since the controller 50 determines that the process is not in progress and activates the buildup removal mechanism 40, there is no need to worry about negatively impacting the pest control process within the pest control device 4. Additionally, in the case of non-processing, since nitrogen gas also flows through the pest control device 4, the pressure sensor 19 can detect the increase in internal pressure of the air intake nozzle 16 when buildup 17 is generated. Therefore, even if the buildup removal mechanism 40 is activated only in the case of non-processing, the buildup 17 can be removed efficiently.

[0050] Furthermore, the amount of water used to remove the deposit 17 is relatively small, approximately a few cc, as described above, but it is sufficient to reduce the temperature change for the purpose of removal and does not significantly affect the operation of the pest control device 4. More specifically, because the amount of water sprayed into the pest control device 4 is small, it evaporates immediately after the deposit 17 is removed. Therefore, for example, there will be no change in the temperature state of the combustion chamber 11 due to residual water droplets in the pest control device 4. Thus, according to this embodiment, the deposit 17 can be removed efficiently without reducing the pest control performance of the pest control device 4.

[0051] Furthermore, the present invention is not limited to the above-described embodiments, and various changes or combinations can be made without departing from the spirit of the present invention. All technical matters included in the technical concept described in the claims are subject to the present invention. The above embodiments show preferred examples, but those skilled in the art can implement various substitutions, modifications, variations, combinations, or improvements based on the content disclosed in this specification, and all of these are included within the technical scope described in the appended claims.

[0052] For example, in addition to the combustion type described above, the pest control device 4 may be plasma type or other forms. For example, in the case of a plasma type pest control device, the power consumption in the plasma generating device can be reduced.

[0053] Alternatively, a two-way valve may be used to replace the same configuration of the three-way valve 41 and the three-way valve 42.

[0054] Alternatively, nitrogen can be replaced by, for example, factory air or other gases that are normally supplied to the factory. Alternatively, antifreeze or other liquids can be used instead of water. That is, the mixed fluid can be the gas discharged from the purifying device 4 or, depending on the operating environment, the preferred one.

[0055] Also, depending on the amount of water to be stored, a storage tank can be used instead of storage piping P3.

[0056] Of course, the stack removal mechanism 40 can also be operated manually without the control of the controller 50 to spray the mixture of nitrogen and water onto the stack 17. [Simplified Explanation of the Diagram]

[0016] Figure 1 is an overall structural diagram of the exhaust gas treatment system used in this invention. Figure 2 is a detailed structural diagram showing the pest control device of an embodiment of this invention. Figure 3 is a structural diagram of the buildup removal mechanism shown in Figure 2. Figures 4(a) to (d) are diagrams showing the sequence of operation of the buildup removal mechanism.

Claims

1. A pest control device comprising a deposit removal mechanism for removing deposits generated during the treatment of exhaust gases; wherein the deposit removal mechanism comprises: a storage section for storing liquid; a gas supply section for supplying pressurized gas to the storage section; and a valve for spraying a mixture of the liquid stored in the storage section and the gas supplied by the gas supply section.

2. The pest control device of claim 1, wherein the pest control device further comprises: a pressure sensor that detects the pressure at the inlet of the exhaust gas; and a control unit that controls the opening and closing of the valve; and the control unit controls the valve to open when the pressure at the inlet exceeds a threshold.

3. The pest control device of claim 2, wherein the control unit, after opening the valve, keeps the valve in an open state for a period of time up to the elapsed period of a specific time.

4. The pest control device as claimed in claim 3, wherein the specific time is set to a time longer than the time during which the liquid stored in the storage section is completely sprayed.

5. The pest control device according to any one of claims 2 to 4, wherein the control unit controls the valve to be in a closed state during the period when the pest control device is eliminating the exhaust gas.

6. A buildup removal mechanism, which is applied to a pest control device for removing harmful gases and for removing buildup generated during the removal of harmful gases; and the buildup removal mechanism comprises: a storage section for storing liquid; a gas supply section for supplying pressurized gas to the storage section; and a valve for spraying a mixture of the liquid stored in the storage section and the gas supplied by the gas supply section.

7. A method for removing deposits, comprising: a first step of storing a liquid; a second step of supplying pressurized gas to the liquid stored in the first step; and a third step of spraying a mixture of the liquid and the gas generated in the second step onto the deposits to remove the deposits.

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