JP5499149B2 - Exhaust gas treatment method - Google Patents

Description

  The present invention relates to an exhaust gas treatment method, and more particularly, to an exhaust gas treatment method for removing harmful gas components in exhaust gas discharged from manufacturing equipment used in the manufacture of semiconductor devices, flat displays, solar cells, magnetic thin plates and the like.

In the process of manufacturing semiconductor products such as semiconductor integrated circuits, liquid crystal panels, solar cells and their panels, magnetic disks, etc., an apparatus that generates plasma in an inert gas atmosphere and performs various processing of semiconductor products using the plasma is widely used. It has been. When the manufacturing process is etching, the exhaust gas discharged from the semiconductor manufacturing facility includes a perfluorocarbon-based reaction product such as CF ₄ , C ₂ F ₆ , and SiF ₄ together with a dilution gas. . The reaction product contained in such exhaust gas has a high global warming potential and cannot be discharged as it is, and needs to be discharged after detoxification treatment.

  In addition, when the manufacturing process is a film forming process, a metal hydride-based reaction product such as monosilane, a by-product thereof, and the like are included together with a dilution gas. Since these are highly reactive, it is necessary to discharge them after detoxification treatment for safety.

Furthermore, a polymer reaction product is also produced by the exhaust gas becoming atmospheric pressure before the detoxification treatment, for example, SiF ₄ becomes a gel polymer solid by association with water molecules, and CF ₄ These precursors generate a polymer by collision of gas molecules under atmospheric pressure, which causes clogging of the exhaust pipe. For this reason, a large amount of gas is always introduced into the vacuum pump to prevent unexpected deposition of reactants.

  The apparatus for detoxifying exhaust gas discharged from the manufacturing facility includes a method of detoxifying by contact with a liquid, for example, water, a reaction with a solid processing agent, or a physical chemical adsorption to a solid processing agent. There is a way to make it harmless. An apparatus that is rendered harmless by reaction or adsorption with a solid processing agent has at least two cylinders for continuous detoxification, and performs continuous operation by switching the filling cylinders.

  In particular, perfluorocarbon-based reaction products and metal hydride-based gases are detoxified by physical chemical adsorption and reaction on solid processing agents due to their emission regulations, and the reaction products and metal In accordance with the flow rate of the hydride-based gas, detoxification is achieved by an apparatus using an appropriately designed filling cylinder. That is, in order to efficiently perform reaction or physical / chemical adsorption, the gas flow rate range is determined, and the cylinder diameter and cylinder length are determined from the amount of introduced gas. Furthermore, in order to determine whether or not the detoxification process is appropriately performed, a detector that detects the concentration of harmful components may be provided at the inlet or outlet of the filling cylinder (see, for example, Patent Document 1). .

  On the other hand, in the manufacturing process, a reactive gas is constantly introduced in order to advance the process by single wafer processing for processing each processing substrate or batch processing for processing a plurality of processing substrates for a certain period of time. As a result, the concentration of the component gas to be processed (hazardous component) in the exhaust gas always fluctuates according to the loading / unloading of the processing substrate into / from the manufacturing apparatus. For this reason, the apparatus design is made on the basis of the maximum flow rate in the manufacturing process, resulting in an increase in the size of the processing apparatus.

  To estimate the stable operation of the treatment equipment and the breakthrough time of the treatment agent, measure the concentration of the detoxification target substance contained in the exhaust gas and measure the flow rate of the exhaust gas, and then check the exhaust gas based on the measured concentration and flow rate. It has been proposed to optimize the device design by adjusting the amount of dilution gas introduced into the system (see, for example, Patent Document 2).

  In addition, in the case of adsorption type processing equipment, the adsorbent corresponding to about half the length of the adsorption band is unused (unadsorbed) at the time when adsorption is completed. Needed to be filled. For this reason, it is difficult to reduce the size of the adsorption cylinder. For this reason, a serial adsorption device composed of two four-way switching valves that allow the intake duct to communicate freely has been proposed (see, for example, Patent Document 3).

  Similarly, when the exhaust gas treatment device is used, two cylinders are connected in series, and when one of the adsorption cylinders is replaced, they are connected in parallel. At the time of use, the exchanged adsorption cylinder is the other adsorption cylinder. It is also proposed that exhaust gas is introduced from the lower part of each adsorption cylinder, an indicator is provided on the upper part, and when the indicator detects the exhaust gas, the adsorption cylinder is placed in parallel when the exhaust gas is processed. (For example, refer to Patent Document 4).

JP 2002-228583 A JP 2001-353422 A JP 60-818 JP-A-4-358516

  According to the method described in Patent Document 2, although the effect of reducing the size of the apparatus is recognized as compared with the prior art, the amount of gas to be processed increases by the amount of newly introduced gas, so that it is difficult to further reduce the size of the apparatus. It was. Moreover, in what was described in patent document 3, there was no description about the method of reproduction | regeneration (desorption) of an adsorption cylinder, and there was a difficulty in practicality. Further, even the one described in Patent Document 4 does not describe any purge method after the parallel state, and there is a danger existing in the switching valve and the outlet pipe downstream from the indicator part before the adsorption cylinder is replaced. It is unclear how to treat various exhaust gases. Furthermore, there is no description about means for confirming the soundness of the indicator.

  Therefore, the present invention can reliably treat exhaust gas while effectively using the gas treating agent filled in the filling cylinder, and can safely discharge the filling cylinder without releasing the exhaust gas outside the system even when the filling cylinder is replaced. It is an object to provide an exhaust gas treatment method that can be replaced.

  In order to achieve the above object, the exhaust gas treatment method of the present invention is the exhaust gas treatment method in which harmful components in the exhaust gas are removed by the first and second filling cylinders each filled with a gas treating agent. Is a removal treatment step for removing harmful components present in the exhaust gas introduced from the exhaust gas path, an exhaust gas purge step for purging the exhaust gas after the removal treatment step, a step of replacing the filling cylinder after the exhaust gas purge step, An atmospheric gas component purge process for purging the atmosphere in the replaced filling cylinder, and a gas introduced from the filling cylinder that is performing the removal process after the atmospheric gas component purge process and introduced through the detection means and then discharged. When the first filling cylinder is performing the removal process step, the second filling cylinder introduces the processing gas derived from the first filling cylinder through the detection means and then discharges it. When the detection means detects a harmful component, the first filling cylinder is switched from the removal treatment process to the exhaust gas purging process, and the second filling cylinder is switched from the waiting process to the removal treatment process, While the purge gas derived in the exhaust gas purging process of the first filling cylinder is introduced into the second filling cylinder in the removal processing process through the detection means, the second filling cylinder performs the removal processing process, When the detection means no longer detects harmful components in the purge gas, the exhaust gas purging step is terminated, the first filling cylinder is replaced with a new filling cylinder, and then the atmospheric gas components in the replaced first filling cylinder It is characterized by switching to a standby process after performing a purge process.

  According to the present invention, the exhaust gas from the semiconductor manufacturing facility is removed through one filling cylinder, the processing gas derived from the filling cylinder is introduced into the detection means, and harmful components are detected. Because it can be discharged out of the system through the process, even if the amount of exhaust gas and the concentration of harmful components fluctuate due to the process of semiconductor manufacturing equipment, it is possible to reliably remove harmful components with one filling cylinder, Even if the gas treatment agent in one filling cylinder breaks through and harmful components are detected in the processing gas, the removal treatment can be performed in another filling cylinder, so the gas treatment agent in one filling cylinder can be used effectively. As a result, the waste of the gas treatment agent can be eliminated, and the exhaust gas treatment apparatus including the filling cylinder can be downsized.

  In addition, the replacement of the one filling cylinder after the harmful component is detected in the processing gas is performed by purging the harmful component remaining in the filling cylinder with the purge gas, and the harmful component is not detected in the purge gas by the detection means. By doing so, there is no risk of harmful components remaining in the filling cylinder and the surrounding pipes, and therefore, no harmful components are released outside the system, and the filling cylinder can be replaced safely. .

It is a block diagram which shows one example of the exhaust gas processing apparatus which enforces the exhaust gas processing method of this invention. It is explanatory drawing which shows an example of a detection means. It is explanatory drawing which shows an example of the waste gas processing method of this invention. It is a block diagram which shows the other example of the exhaust gas processing apparatus which enforces the exhaust gas processing method of this invention.

  FIG. 1 is a block diagram showing an embodiment of an exhaust gas treatment apparatus for carrying out the exhaust gas treatment method of the present invention, FIG. 2 is an explanatory view showing an example of a detection means, and FIG. 3 is another example of the exhaust gas treatment method of the present invention. It is explanatory drawing shown.

  This exhaust gas treatment apparatus includes two filling cylinders 10 and 20 filled with gas treatment agents 11 and 21 that detoxify harmful components by physical chemical adsorption or reaction, and a processing gas derived from the respective filling cylinders 10 and 20. And detecting means 30 for detecting harmful components therein.

  The gas inflow portions 10a and 20a of the filling cylinders 10 and 20 are discharged from a semiconductor manufacturing facility used in the manufacture of semiconductor devices, flat displays, solar cells, magnetic thin plates, and the like, and are discharged from an exhaust gas path 41 to an exhaust gas treatment device. Inlet passages 12 and 22 for introducing the exhaust gas to be introduced into the filling cylinders 10 and 20 are provided, and inlet valves 12V and 22V for switching the filling cylinder for introducing the exhaust gas are provided in the inlet passages 12 and 22, respectively. Each is provided.

  In addition, purge gas introduction for introducing purge gas supplied from a purge gas supply source (not shown) into the respective filling cylinders 10 and 20 on the downstream side (filling cylinder side) of the inlet valves 12V and 22V in the respective inlet passages 12 and 22 respectively. The paths 13 and 23 and the detection means outlet paths 14 and 24 connected to the detection means 30 are branched, and a purge valve (purge gas introduction) for controlling the introduction of the purge gas is provided in each of the purge gas introduction paths 13 and 23. Valves) 13V and 23V are provided, and the detection means outlet passages 14 and 24 are provided with detection means outlet valves 14V and 24V, respectively.

  On the other hand, the gas outflow portions 10b and 20b of the filling cylinders 10 and 20 are respectively provided with outlet passages 15 and 25 having outlet valves 15V and 25V, respectively, and the outlet valves 15V and 25V in the outlet passages 15 and 25 are provided. From the upstream side (filling cylinder side), there are branched purge gas discharge paths 16 and 26 having purge gas outlet valves 16V and 26V, respectively, and detection means inlet paths 17 and 27 connected to the detection means 30. The means inlet passages 17 and 27 are provided with detecting means inlet valves 17V and 27V, respectively.

  The detection means 30 includes a detection unit through which a gas to be measured flows, and a control device 32 including an input unit 32a, a calculation unit 32b, an output unit 32c, and the like, and a signal from the detection unit is input. The component concentration is calculated based on the intensity of the signal input to the calculation unit 32b via the unit 32a and input by the calculation unit 32b. The calculated component concentration signal is output from the output unit 32 c to the device control unit 33.

  The apparatus control unit 33 includes a signal input / output unit 33a and a signal storage / comparison calculation unit 33b. The input / output unit 33a is configured to output exhaust gas in addition to the component concentration signal from the control unit 32. A signal from the manufacturing facility that discharges the gas is also received, and a signal for operating the alarm is transmitted to the alarm generation unit 34 connected to the device control unit 33. The storage / comparison operation unit 33b compares the set concentration stored in advance and the component concentration received from the control device 32, generates an alarm activation signal, and also refers to the signal received from the manufacturing facility. For example, a valve control signal for performing valve opening / closing control is generated.

  The detection unit includes a first gas inflow / outflow path 35 where the detection means outlet path 14 on the filling cylinder 10 side and the detection means inlet path 17 merge, the detection means outlet path 24 on the filling cylinder 20 side, and the A second gas inflow / outflow path 36 joined with the detection means inlet path 27 and a gas discharge path 37 provided with a gas discharge valve 37V are provided. The gas discharge path 37 and the outlet passages 15 and 25 release gas. It joins the path 42.

  The filling cylinders 10 and 20 are airtight containers in which flanges serving as the gas inflow portions 10a and 20a and the gas outflow portions 10b and 20b are provided at both ends of a cylindrical container for filling the gas treating agents 11 and 21, respectively. In addition, a filter for preventing the gas treatment agents 11 and 21 from flowing out is provided inside. Further, a filter, a punching plate, or the like can be provided in the upper portion of the agent or the upper flange portion in the filling cylinders 10 and 20 in order to prevent gas drift and gas treatment agent rolling.

  Moreover, in order to perform adsorption | suction or reaction with the gas processing agents 11 and 21 on the optimal conditions on the filling cylinders 10 and 20, a heating means and a cooling means can be provided. As the heating mechanism, a method of winding a heater around the outer surface of the cylinder is suitable, but other methods can also be adopted. Moreover, as a cooling means, a method of winding a metal pipe with good thermal conductivity around the outer surface of the cylinder and allowing a coolant or water to flow through the inside is suitable, but other methods can also be adopted.

  The flow direction of the gas in the filling cylinders 10 and 20 is desirably set so as to be introduced from the upper part of the cylinder and discharged from the lower part of the cylinder. Even if the gas flow direction is directed from the lower part of the cylinder to the upper part, sufficient removal treatment can be performed.For example, when a liquid such as water is generated by the removal process of harmful components, the exhaust gas is introduced from the lower part. In some cases, the gas flow resistance changes with time due to the generation of liquid and the processing capacity changes. Moreover, it can also prevent that a gas processing agent flows by the gas which distribute | circulates by introducing gas from the upper part. The gas treatment agents 11 and 21 are appropriately selected as a solid treatment agent according to the harmful components in the exhaust gas to be treated, and are not particularly limited. For example, the harmful components may be monosilane or arsine. In the case of a metal hydride-based gas such as the above, copper hydroxide or one in which copper hydroxide is supported on an inorganic material is suitable. In addition, when the harmful component is a fluorine compound-based gas, an alkali metal such as sodium is supported on an inorganic material, an oxide or hydroxide of an alkaline earth metal such as calcium, or these are inorganic materials It is possible to use what is carried on the surface.

  In order to reduce the pressure loss of the treatment agent itself, such gas treatment agents 11 and 21 are preferably used in the form of pellets or granules, but the size and shape of the agent is the shape of the treatment cylinder. It can be appropriately determined depending on the size. Further, the filling amount of the gas treatment agents 11 and 21 can be determined in consideration of the concentration of harmful components contained in the exhaust gas, the removal efficiency of the gas treatment agent, the replacement frequency, etc. Designed to withstand continuous use for at least 2 weeks taking into account the replacement time.

  The valve and piping used in the apparatus are preferably made of a metal having airtightness such as stainless steel, and the diameter of the valve and the pipe can be appropriately determined according to the exhaust gas flow rate and the purge gas flow rate to be processed. In addition, in order to reduce gas decomposability and improve corrosion resistance, passivation treatment, for example, chromium oxide passivation film, alumina passivation film, fluoride passivation film is appropriately formed on the inner surface of valves and pipes Can be kept. Here, the purge gas is optimally an inert gas present in the exhaust gas, but other inert gases can also be used.

  The detection means 30 is capable of detecting harmful components from ppm order to% order, and more preferably, capable of detecting harmful components of 10 ppm or more and less than 1%. Various detection means can be used as the detection means 30 as long as it has a predetermined detection accuracy. For example, a laser spectrometer, a Fourier transform infrared spectrometer (FT-IR), a non-dispersion Those utilizing light absorption such as a type infrared spectrophotometer, and those utilizing mass measurement such as a mass spectrometer and gas chromatograph mass spectrometer (GC-MS) can be suitably used.

  In various detection means, the direction of the detection probe, for example, the light irradiation direction in the case of a laser spectrometer or FT-IR, is preferably a direction orthogonal to each of the paths 35, 36, and 37. . Moreover, the gas contact part of the detection part may form a passivating film as necessary, and may be heated in the range of 100 to 130 ° C. to prevent adsorption of unexpected impurities such as moisture. .

  The alarm activation signal and the valve control signal from the storage / comparison calculation unit 33b of the device control unit 33 may be generated immediately after the detection unit 30 detects the harmful component. More than the time set in the timer, for example, when detected for more than two loading / unloading times of the processing substrate in the semiconductor manufacturing facility, or the number of detections of harmful components in the detection means 30, and further the amount of harmful components is It is preferable to generate an alarm operation signal or a valve control signal by determining that the gas processing agent is broken through when the set amount is exceeded. Further, the control device 32 and the device control unit 33 in the detection unit 30 may be integrally formed, or may be appropriately divided. Further, it can be set so that the soundness of the detection means 30 is confirmed when purge gas is circulated through the detection unit.

  Next, an exhaust gas treatment method using the exhaust gas treatment apparatus shown in FIG. 1 will be described based on FIG. In FIG. 3, a thick line indicates a path through which gas flows, and in each valve, a valve expressed as “open” in the description is in an open state, and the other valves are in a closed state. Moreover, the code | symbol is attached | subjected only to the component required for description.

  First, FIG. 3A shows a state in which one filling cylinder 10 performs a process of removing harmful components in the exhaust gas (removal processing process), and the other filling cylinder 20 performs a standby process. . In this state, the inlet valve 12V, the detecting means inlet valve 17V, the detecting means outlet valve 24V and the outlet valve 25V are open, and the exhaust gas discharged from the manufacturing equipment is removed from the exhaust gas path 41 through the inlet path 12. Is introduced into the filling cylinder 10. The harmful components present in the exhaust gas introduced into the filling cylinder 10 are removed by contact with the gas treatment agent 11 filled inside the cylinder, and the harmless exhaust gas (treatment gas) is discharged from the filling cylinder 10. It is led out to the exit path 15.

  Since the outlet valve 15V is closed, the entire amount of the processing gas in the outlet path 15 flows into the detection means inlet path 17, flows into the detection section of the detection means 30 through the first gas inflow / outflow path 35, and is detected. After the harmful component is detected by 30, it flows out to the second gas inflow / outflow path 36. The processing gas in the second gas inflow / outflow path 36 is introduced into the other filling cylinder 20 that is performing the standby process through the downstream side of the detection means outlet path 24 and the inlet path 22 and comes into contact with the gas processing agent 21. However, the gas flows toward the gas outlet 20b, is led out to the outlet path 25, and is discharged from the processing gas discharge path 42 to the outside of the system.

  The removal process step of the filling cylinder 10 is continued until a harmful component is detected by the detection means 30, and ends when the amount of harmful component, the detection time, the number of detections, and the like are set in advance, as shown in FIG. As shown in (b), the filling cylinder 10 is switched to the purge process, and the filling cylinder 20 is switched to the removal process. The switching operation of this step is performed by closing the inlet valve 12V and opening the inlet valve 22V and the purge gas introduction valve 13V.

  Thereby, the exhaust gas from the exhaust gas path 41 is introduced into the filling cylinder 20 that has been switched to the removal process through the inlet path 22. The processing gas from which harmful components have been removed by the filling cylinder 20 is led out to the outlet path 25 and discharged from the processing gas discharge path 42 to the outside of the system. On the other hand, the purge gas introduced from the purge gas introduction path 13 through the downstream side of the inlet path 12 into the filling cylinder 10 switched to the purge step is upstream of the outlet path 15 from the gas outlet 10b, the detection means inlet path 17 and The gas is introduced into the detection means 30 via the first gas inflow / outflow path 35, and the exhaust gas remaining in the filling cylinder 10 and these paths is purged.

  The purge gas led out from the detection means 30 to the second gas inflow / outflow path 36 is introduced into the filling cylinder 20 from the detection means outlet path 24 through the downstream side of the inlet path 22, and comes into contact with the gas processing agent 21. The harmful components in the exhaust gas remaining in the filling cylinder 10 and the paths 12, 15, 17, and 35 at the time of the process switching are removed. The purge gas from which harmful components have been removed is discharged from the exit path 25 through the processing gas discharge path 42 to the outside of the system. The purging process of the filling cylinder 10 ends when no harmful component is detected in the purge gas by the detection means 30 and when a purge gas of a predetermined amount or more is circulated through the filling cylinder 10, and the replacement of the filling cylinder 10 is performed. Is done.

  The replacement of the filling cylinder 10 is performed by detaching a joint provided at an appropriate position in a state where the purge gas introduction valve 13V and the detection means inlet valve 17V are closed and the gas flow in the filling cylinder 10 is shut off. After the new filling cylinder 10 is attached, the atmospheric component purge process shown in FIG. 3C is performed. In this atmospheric component purge step, the purge gas introduction valve 13V and the purge gas lead-out valve 16V are opened, and the purge gas introduced from the purge gas introduction path 13 causes the downstream side of the inlet path 12, the upstream side of the filling cylinder 10 and the outlet path 15, and the like. The invading atmospheric components are discharged from the purge gas discharge path 16.

  On the other hand, after the introduction of the processing gas and the purge gas from the filling cylinder 10 to the detection means 30 is completed, the outlet valve 25V is closed, and the detection means inlet valve 27V and the gas discharge valve 37V are opened. The derived processing gas flows from the detection means inlet passage 27 through the second gas inflow / outflow passage 36 into the detection unit of the detection means 30, and the detection means 30 detects harmful components in the processing gas. The processing gas led out from the detection means 30 to the gas discharge path 37 is discharged out of the system through the processing gas discharge path 42.

  The atmospheric component purging process of the filling cylinder 10 is completed by circulating a predetermined amount of purge gas, and as shown in FIG. 3D, the purge gas introduction valve 13V, the purge gas outlet valve 16V, and the gas discharge valve 37V are provided. While the detection means outlet valve 14V and the outlet valve 15V are opened, the filling cylinder 10 enters a standby process.

  The stage of performing the standby process of the filling cylinder 10 shown in FIG. 3D is a state in which the filling cylinder 10 and the filling cylinder 20 in FIG. The processing gas passes through the detection means 30, flows back through the first gas inflow / outflow path 35, is introduced from the detection means outlet path 14 to the filling cylinder 10 through the downstream side of the inlet path 12, and is derived from the filling cylinder 10. The processing gas is discharged out of the system from the outlet path 15 through the processing gas discharge path 42.

  When a harmful component is detected in the processing gas derived from the filling cylinder 20, as shown in FIG. 3E, the inlet valve 22V is closed, the inlet valve 12V and the purge gas introduction valve 23V are opened, and the filling cylinder 10 is removed. While being switched to the processing step, the filling cylinder 20 is switched to the purge step. At this stage, the filling cylinder 10 and the filling cylinder 20 in FIG.

  When no harmful components are detected in the purge gas from the filling cylinder 20 by the detection means 30, the valves on the filling cylinder 20 side are closed, the filling cylinder 20 is replaced with a new filling cylinder, and then the purge gas introduction valve 23V and The purge gas outlet valve 26V is opened, and the atmospheric component purging step for the filling cylinder 20 shown in FIG. 3 (f) is performed. This stage is a state where the filling cylinder 10 and the filling cylinder 20 in FIG.

  When the atmospheric component purge process of the filling cylinder 20 is completed, the valves are opened and closed to return to the state shown in FIG. Hereinafter, by repeatedly performing each step of FIG. 3A to FIG. 3F, one of the filling cylinder 10 and the filling cylinder 20 is in a state where the removal treatment process is being performed without fail. Since the other filling cylinder can be replaced with a new filling cylinder, harmful components in the exhaust gas can be continuously removed by both filling cylinders.

  In this way, when removing harmful components continuously, immediately after switching to the removal treatment step, that is, while detecting harmful components in the purge gas derived from the filling cylinder performing the purge step. Except that the detection means 30 always confirms that noxious components in the processing gas derived from the filling cylinder performing the removal treatment step are below the specified value, and is replaced with a new filling cylinder. Since the filling cylinder after the atmospheric component purging process is connected in series via the detection means 30 to the downstream side of the filling cylinder performing the removal treatment process, the gas treatment in the filling cylinder performing the removal treatment process is performed. Even if the agent becomes near breakthrough and sufficient removal treatment cannot be performed, and harmful components flow out, the removal treatment can be surely performed by the downstream side filling cylinder performing the standby step.

Therefore, since harmful components detected by the detecting means 30 to continue the removal process until a preset condition, effectively utilized for removing processed toxic components substantially whole amount of the gas processing agent filled in the filling tube be able to. Thereby, the usage-amount of a gas processing agent can be reduced significantly conventionally , and size reduction of a filling cylinder, ie, size reduction and price reduction of an exhaust gas processing apparatus, can be achieved.

In addition, when the amount of exhaust gas and the concentration of harmful components fluctuate greatly depending on the process of the manufacturing equipment, it is necessary to design the filling cylinder according to the maximum value of the exhaust gas flow rate and the maximum value of the harmful component concentration in the conventional exhaust gas treatment device In the case where harmful components are removed by a filling cylinder using physical / chemical adsorption or reaction, there is an unadsorbed or unreacted region in the gas processing agent on the downstream side in the gas flow direction of the filling cylinder. Normally, the height of the filling cylinder, that is, the filling amount of the gas treatment agent, is determined taking this region into account, and with conventional exhaust gas treatment devices, even if the exhaust gas flow rate or harmful component concentration reaches the maximum value, sufficient removal treatment is performed. A large amount of gas processing agent is used compared to the required amount so that the gas processing agent having a sufficient removal processing capacity is replaced without being effectively used when the filling cylinder is replaced. Become.

  For this reason, in the conventional exhaust gas treatment device, in order to reduce the size, it was necessary to individually design with specifications according to the exhaust gas flow rate and harmful component concentration of the production facility. By setting one of the filling cylinders as a standby process downstream of the detection means 30, the exhaust gas flow rate temporarily reaches a maximum value, or the harmful component concentration temporarily reaches a maximum value and the removal treatment process proceeds. Even if harmful components flow out from the cylinder, the removal process of the harmful components that flowed out can be performed reliably in the filling cylinder in the standby process, so filling is performed according to the maximum value of exhaust gas flow rate and maximum value of harmful component concentration. There is no need to design a cylinder, and the exhaust gas treatment device can be reduced in size and improved in versatility. In particular, when three or more filling cylinders are used, when one or more filling cylinders are replaced or purged, one of the other two filling cylinders is removed, and the other is a standby process. Therefore, the harmful components can be removed more reliably and the gas treating agent can be used more effectively.

  In addition, even when a problem such as drifting that significantly reduces the processing performance occurs in the filling cylinder, the occurrence of the problem can be detected immediately by the detection of the harmful component by the detection means 30, and the alarm generation unit 34 generates an alarm. Since the person in charge can be notified promptly by operating, measures necessary for resolving the problem can be quickly taken. Even in this case, since the removal process is performed by the filling cylinder in another standby process, no harmful components are discharged to the outside.

  Furthermore, by introducing the purge gas derived from the filling cylinder during the purge process to the detection means 30 and detecting harmful components in the purge gas, the purge gas amount can be easily optimized and the purge time can be shortened. . At this time, it is possible to confirm the soundness of the detection means 30 itself, for example, the absence of zero point drift, by introducing a purge gas that does not contain harmful components into the detection unit.

  Further, the purge process does not need to be started immediately after the process is switched. For example, if the purge gas derived from the detection means 30 is introduced into the filling cylinder where the purge process is performed by merging with the exhaust gas, the gas flow rate is related. When it is not desirable, when the exhaust gas is not generated from the production facility, for example, the purge process may be performed when the substrate is replaced. In this control, the apparatus control unit 33 receives an operation state signal from the manufacturing facility, and based on this signal, a predetermined valve is opened and closed to perform purge and exhaust gas treatment alternately.

  That is, when the manufacturing facility is a single-wafer type semiconductor manufacturing apparatus, there is always a time required to replace each substrate, and during that time, exhaust gas containing harmful components is not discharged. In addition, since the exhaust gas is not discharged for a longer time in the exchange for each lot, the time during which these exhaust gases are not discharged is allocated to the purge time, and the exhaust gas is sufficiently exhausted in the other filling cylinder until the required purge time is reached. It is sufficient to set it so that it can be removed, and harmful components do not leak outside the system even when the filling cylinder is switched.

  In addition, the purge gas derived from the filling cylinder during the purge process is not passed through the detection means 30, and the purge gas outlet valve (16V, 26V) is opened, and the purge gas is supplied to the abatement equipment separately provided from the purge gas discharge path (16, 26). You may make it send out and remove the harmful component in purge gas with this abatement equipment.

  In the purge process, the purge gas is continuously circulated. However, a batch purge that alternately opens the purge gas introduction valves 13V and 23V and the purge gas outlet valves 16V and 26V may be adopted. The evacuation device may be connected to a valve-side path that is open with the 23V or purge gas lead-out valves 16V and 26V closed, or evacuation may be performed, or batch purge and evacuation may be combined. In particular, when the evacuation device is a helium leak detector, it is more preferable because it can simultaneously check for leaks of the filling cylinders 10 and 20 and the joints of the respective paths.

  Further, the replacement of the filling cylinder may be merely replacement of the filled gas processing agent. Even if it takes a long time to replace the filling cylinder or the gas treatment agent, if the duration of the removal treatment process is set to be longer than the time required for these replacements, for example, 2 weeks or more, harmful components in the exhaust gas Is not discharged out of the system.

  FIG. 4 is a block diagram showing another embodiment of the exhaust gas treatment apparatus for carrying out the exhaust gas treatment method of the present invention. In the following description, the same components as those in the exhaust gas treatment apparatus shown in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, the detection means inlet paths 17 and 27 branched from the outlet paths 15 and 25 of the respective filling cylinders 10 and 20 are joined to the detection means inflow path 38 and connected to the gas inflow portion of the detection means 30 and are detected. The detection means outlet paths 14 and 24 are branched from the detection means outflow path 39 connected to the gas outflow portion of the means 30 and connected to the inlet paths 12 and 22 of the respective filling cylinders 10 and 20. The gas discharge path 37 is branched from Also in the exhaust gas treatment apparatus configured as described above, the exhaust gas can be treated in the same procedure as that shown in FIG. 3 by opening and closing each valve in the same manner as described above.

  The purge gas derived from each of the filling cylinders 10 and 20 is discharged from the outlet passages 15 and 25 through the processing gas discharge path 42 by opening the outlet valves 15V and 25V. The purge gas discharge paths 16 and 26 having 16 V and 26 V, respectively, may be branched from the outlet paths 15 and 25 and discharged.

Example 1
The exhaust gas treatment apparatus shown in FIG. 1, is operated in the procedure shown in FIG. 3, was removed of the SiF ₄ gas in an exhaust gas discharged from the single-wafer fabrication facility. Most of the gas discharged from the manufacturing facility is argon (Ar). When the manufacturing facility is processing the substrate, about 3% of SiF ₄ is discharged, and when the substrate is carried into and out of the manufacturing facility. Ar containing several tens of ppm of SiF ₄ was discharged. The exhaust gas flow rate was about 0.4 L / min during substrate processing, and 0.3 L / min during substrate loading / unloading. The processing time was 5 minutes when the substrate was processed, and 1 minute when the substrate was loaded and unloaded. The pressure of the exhaust gas was about 10 Torr. However, the above conditions are initial basic conditions, and the SiF ₄ concentration during substrate processing varies between 0.1% and 3% depending on the processing substrate to be manufactured, and the processing time is also arbitrary between 3 minutes and 15 minutes. Had changed. Further, the exhaust gas flow rate during the substrate processing varied between about 0.4 L / min and about 1.5 L / min.

With respect to the exhaust gas conditions, a filling cylinder having a diameter of 125 mm was used, and 20 kg of a calcium oxide agent was filled therein as a gas treatment agent. The superficial velocity at the initial basic conditions was 3.7 cm / sec, and the superficial velocity at the maximum exhaust gas flow rate was approximately 14 cm / sec. When processing was performed while measuring the concentration of SiF ₄ in the processing gas by the detecting means, SiF ₄ was detected in 420 processed sheets. However, the concentration was about 1 ppm, and when the exhaust gas flow rate was 1.5 L / min, SiF 4 was not detected when the exhaust gas flow rate was less than 0.8 L / min. Therefore, the time when the concentration of SiF ₄ in the exhaust gas exceeded 100 ppm was taken as the breakthrough point of the filled cylinder, and the substrate processing was continued while measuring, and finally 480 substrates could be processed. At the time of processing 480 sheets, no SiF ₄ was detected at the exit of the filling cylinder during the standby process.

Comparative Example 1
Under the same exhaust gas conditions as in Example 1, an exhaust gas treatment experiment was performed using a filled cylinder of the same size. Here, only the detector is connected to the subsequent stage of the filling cylinder, and the second filling cylinder is not connected. As a result of the experiment, SiF ₄ was detected in the same manner as in the example with about 420 processed sheets, and thereafter, SiF ₄ could not be detected. However, the number of sheets detected continuously at 1 ppm, which is the limit concentration of SiF ₄ , was 430, and the number of processed sheets was 50 fewer than that in Example 1. From this result, the number of sheets that can be processed with the expectation of safety was 420 sheets. Therefore, it can be seen that a loss of about 12% occurs with the same amount of gas processing agent. In order to obtain the same processing performance as in Example 1, it is necessary to increase the gas processing agent charging amount by 2.4 kg. I understood it.

Example 2
In order to calculate the unreacted portion of the gas treatment agent filled in the filling cylinder after the 420th sheet where SiF ₄ was first detected after performing the same operation as in Example 1, the concentration of SiF ₄ introduced into the filling cylinder and The number of sheets until the processing tube exit, that is, the SiF ₄ concentration detected by the detecting means coincided was examined. As a result, the number of processable sheets was about 500. At this time, no SiF ₄ was detected at the exit of the filling cylinder during the standby process.

Example 3
Using the filling cylinder completely broken through in Example 2, the filling cylinder was replaced. In order to replace the filling cylinder, a predetermined valve was opened and closed to switch the removal process step to the other filling cylinder side, and then Ar was vented from the upper part of the filled filling cylinder at 0.5 L / min. The pressure at this time is 10 Torr. When the SiF ₄ concentration was continuously measured by the detection means, after the start Ar breathable, SiF ₄ concentration becomes less than 1ppm in about 10 minutes, it was carried out an exchange of breakthrough already filled barrel to stop Ar ventilation. A new filling cylinder filled with 20 kg of a new calcium oxide agent is attached to the device, and a leak inspection is performed with a He leak detector while evacuating from the bottom of the new filling cylinder. The leakage is 1 × 10 ⁻⁹ Pa · m ³ / s. It was confirmed that: Thereafter, Ar was vented from the top of the new filling cylinder at 3 L / min for about 20 minutes to complete the air purge operation of the filling cylinder. After that, SiF ₄ -containing gas passed through the detection means was passed through the new filling cylinder, and the SiF ₄ concentration was measured at the outlet of the new filling cylinder, but no SiF ₄ was detected.

  DESCRIPTION OF SYMBOLS 10,20 ... Filling cylinder, 10a, 20a ... Gas inflow part, 10b, 20b ... Gas outflow part, 11, 21 ... Gas treatment agent, 12, 22 ... Inlet path, 12V, 22V ... Inlet valve, 13, 23 ... Purge gas Introduction path, 13V, 23V ... purge gas introduction valve, 14, 24 ... detection means outlet path, 14V, 24V ... detection means outlet valve, 15, 25 ... outlet path, 15V, 25V ... outlet valve, 16, 26 ... purge gas discharge path , 16V, 26V ... purge gas outlet valve, 17, 27 ... detection means inlet path, 17V, 27V ... detection means inlet valve, 30 ... detection means, 32 ... control device, 32a ... input unit, 32b ... calculation unit, 32c ... output 33, device control unit, 33a, input / output unit, 33b, storage / comparison calculation unit, 34, alarm generation unit, 35, first gas inflow / outflow path, 36, second gas inflow / outflow Road, 37 ... gas discharge path, 37V ... gas discharge valve, 38 ... detector inflow path 39 ... detector outflow path 41: exhaust gas passage, 42 ... gas discharge path

Claims (1)

In the exhaust gas treatment method for removing harmful components in the exhaust gas with the first and second filling cylinders respectively filled with a gas treatment agent,
Each filling cylinder has a removal treatment process for removing harmful components present in the exhaust gas introduced from the exhaust gas route, an exhaust gas purge process for purging the exhaust gas after the removal treatment process, and a replacement of the filling cylinder after the exhaust gas purge process. Process, an atmospheric gas component purging step for purging the atmosphere in the replaced filling cylinder, and a gas derived from the filling cylinder performing the removal treatment process after the atmospheric gas component purging process and introduced through the detection means. And a standby process to discharge
When the first filling cylinder is performing the removal processing step, the second filling cylinder performs a standby step of introducing and discharging the processing gas derived from the first filling cylinder through the detection means, and the detection means When the harmful component is detected, the first filling cylinder is switched from the removal treatment process to the exhaust gas purging process, and the second filling cylinder is switched from the standby process to the removal treatment process,
While the purge gas derived in the exhaust gas purging process of the first filling cylinder is introduced into the second filling cylinder in the removal processing process through the detection means, the second filling cylinder performs the removal processing process, When the detection means no longer detects harmful components in the purge gas, the exhaust gas purging step is terminated, the first filling cylinder is replaced with a new filling cylinder, and then the atmospheric gas components in the replaced first filling cylinder An exhaust gas treatment method characterized by switching to a standby process after performing a purge process.

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