Exhaust gas detoxification system

Abstract

To provide an exhaust gas detoxification system which can conduct a gas leakage inspection without stopping operation of a semiconductor manufacturing device.SOLUTION: An exhaust gas detoxification system according to the present invention comprises: an exhaust line through which exhaust gas discharged from a semiconductor manufacturing device flows; an exhaust gas treatment device which is provided in the exhaust line and capable of detoxifying the exhaust gas; a leakage inspection line which branches from the exhaust line; and a moisture meter which is provided in the leakage inspection line and capable of measuring a moisture concentration of a sampling gas flowing from the exhaust line to the leakage inspection line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an exhaust gas abatement system. [Background technology]

[0002] In the semiconductor manufacturing process, explosive silane-based gases (e.g., SiH4 and SiH2Cl2), toxic phosphorus-based gases (e.g., PH3), arsenic-based gases (e.g., AsH3), boron-based gases (e.g., B2H6), and other gases are used. These special gases are contained as harmful components in the exhaust gas discharged from semiconductor manufacturing equipment. For this reason, the exhaust gas from semiconductor manufacturing equipment is sent through an exhaust line to an exhaust gas abatement device where it is decomposed (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-023000 A [Patent Document 2] JP 2007-029790 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the exhaust lines of semiconductor manufacturing equipment, the risk of gas leakage increases over time due to loosening of joints caused by vibrations from rotating machines, deterioration of sealing materials due to the corrosiveness of exhaust gas, etc. Therefore, regular gas leakage inspections are necessary to continue safe operation of the equipment.

[0005] Conventionally, when conducting periodic gas leak inspections, it was necessary to stop the operation of the semiconductor manufacturing equipment, such as by closing the isolation valve installed downstream of the semiconductor manufacturing equipment and stopping the vacuum pump installed in the exhaust line for gas extraction.

[0006] An object of the present invention is to provide an exhaust gas abatement system that is capable of carrying out gas leakage inspection without stopping the operation of semiconductor manufacturing equipment. [Means for solving the problem]

[0007] The exhaust gas abatement system according to the first aspect of the present invention comprises: (1) an exhaust line through which exhaust gas discharged from the semiconductor manufacturing equipment flows; an exhaust gas treatment device provided in the exhaust line and capable of removing harmful substances from the exhaust gas; a leakage inspection line branching off from the exhaust line; a moisture meter provided in the leak inspection line and capable of measuring the moisture concentration of sampled gas flowing from the exhaust line to the leak inspection line.

[0008] As one embodiment of the present invention, an exhaust gas abatement system includes: (2) The moisture meter is the exhaust gas abatement system according to (1) above, which is provided with a moisture-sensing part including a metal-organic framework.

[0009] As one embodiment of the present invention, an exhaust gas abatement system includes: (3) The leak inspection line is an exhaust gas abatement system as described in (1) or (2) above, configured to be able to introduce the sampling gas from the exhaust line when an inert gas is flowing in the exhaust line as the exhaust gas.

[0010] As one embodiment of the present invention, an exhaust gas abatement system includes: (4) a vacuum pump provided in the exhaust line upstream of the leak inspection line; The exhaust gas abatement system according to claim 3, further comprising a purification section capable of purifying the inert gas supplied to the vacuum pump and flowing through the vacuum pump into the exhaust line before the inert gas is supplied to the vacuum pump. Effect of the Invention

[0011] According to the present invention, it is possible to provide an exhaust gas abatement system that is capable of carrying out gas leakage inspection without stopping the operation of semiconductor manufacturing equipment. [Brief description of the drawings]

[0012] [Figure 1] 1 is an explanatory diagram of components of an exhaust gas abatement system according to one embodiment of the present invention; [Diagram 2] 2 is an explanatory diagram illustrating a gas flow when exhaust gas treatment is performed in the exhaust gas abatement system shown in FIG. [Diagram 3] 2 is an explanatory diagram illustrating a gas flow when a gas leakage inspection is performed in the exhaust gas abatement system shown in FIG. [Figure 4] 1 is an explanatory diagram of components of an exhaust gas abatement system according to one embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an exhaust gas abatement system according to the present invention will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals.

[0014] FIG. 1 is a diagram showing an exhaust gas abatement system 51 as one embodiment of the exhaust gas abatement system according to the present invention.

[0015] The exhaust gas abatement system 51 includes an exhaust line 2 through which exhaust gas discharged from the semiconductor manufacturing equipment 1 flows. The exhaust gas discharged from the semiconductor manufacturing equipment 1 is exhausted to the outside through the exhaust line 2. The exhaust gas discharged from the semiconductor manufacturing equipment 1 may contain special gases. Examples of the special gases include explosive silane-based gases (e.g., SiH4 and SiH2Cl2), toxic phosphorus-based gases (e.g., PH3), arsenic-based gases (e.g., AsH3), and boron-based gases (e.g., B2H6). Therefore, in the exhaust gas abatement system 51, an exhaust gas treatment device 9 capable of abating the exhaust gas discharged from the semiconductor manufacturing equipment 1 is provided in the exhaust line 2. That is, according to the exhaust gas abatement system 51, the exhaust gas detoxified by the exhaust gas treatment device 9 can be exhausted to the outside.

[0016] Furthermore, the exhaust gas abatement system 51 can inspect the presence or absence of gas leakage in the exhaust line 2 by checking the presence or absence of intrusion of environmental air without stopping the operation of the semiconductor manufacturing equipment 1. Specifically, the exhaust gas abatement system 51 includes a leakage inspection line 13 branching off from the exhaust line 2. In the exhaust gas abatement system 51, a moisture meter 17 capable of measuring the moisture concentration of the sampled gas flowing from the exhaust line 2 to the leakage inspection line 13 is provided in the leakage inspection line 13. Therefore, in the exhaust gas abatement system 51, a gas leakage inspection can be performed by measuring the moisture concentration of the sampled gas flowing from the exhaust line 2 to the leakage inspection line 13 with the moisture meter 17. In other words, according to the exhaust gas abatement system 51, a gas leakage inspection can be performed by flowing the sampled gas into the leakage inspection line 13 without stopping the operation of the semiconductor manufacturing equipment 1.

[0017] The exhaust gas abatement system 51 of this embodiment will be described in detail below.

[0018] As shown in FIG. 1, the exhaust gas abatement system 51 of this embodiment includes an exhaust line 2, an isolation valve 3, a vacuum pump 5, an exhaust switching three-way valve 7, an exhaust gas treatment device 9, an exhaust duct 11, a leak inspection line 13, a sampling gate valve 15, a moisture meter 17, a sampling system switching three-way valve 21, and a sampling pump 23.

[0019] The exhaust line 2 is a line through which exhaust gas discharged from the semiconductor manufacturing equipment 1 flows. The exhaust line 2 of this embodiment is provided with an isolation valve 3, a vacuum pump 5, an exhaust switching three-way valve 7, and an exhaust gas processing device 9. The exhaust line 2 of this embodiment is a line through which exhaust gas discharged from the semiconductor manufacturing equipment 1 flows, but in addition to the exhaust gas discharged from the semiconductor manufacturing equipment 1, for example, an inert gas supplied to the vacuum pump 5 from the outside and discharged through the vacuum pump 5 may be circulated through the exhaust line 2. Specifically, the vacuum pump 5 is provided on the exhaust line 2 upstream of the leak inspection line 13. The inert gas supplied to the vacuum pump 5 from the outside may be, for example, nitrogen gas. A specific example of a configuration in which nitrogen gas N2 as an inert gas is supplied to the vacuum pump 5 from the outside will be described later (see FIG. 4).

[0020] An exhaust duct 11 is connected to the downstream side of the exhaust line 2. By connecting this exhaust duct 11 to exhaust equipment in a factory or the like, the exhaust line 2 can be put into a negative pressure state. In other words, the exhaust gas can flow in the exhaust line 2 under negative pressure. This makes it possible to prevent the exhaust gas from leaking to the outside as much as possible. If the capacity of the exhaust equipment in the factory or the like is insufficient, the exhaust line 2 can be put into a negative pressure state by adding an exhaust fan (not shown) to the exhaust gas processing device 9.

[0021] The exhaust switching three-way valve 7 is provided upstream of the exhaust gas treatment device 9 in the exhaust line 2. The exhaust switching three-way valve 7 can switch the flow of exhaust gas between the exhaust gas treatment device 9 side and the exhaust duct 11 side. However, the exhaust line 2 is not limited to the configuration of this embodiment. The exhaust line 2 may be configured without including the exhaust switching three-way valve 7, for example.

[0022] The exhaust gas treatment device 9 is a device that removes the special gas discharged from the semiconductor manufacturing equipment 1, and may be, for example, a device that removes the special gas by burning it with a burner. However, the method of exhaust gas treatment in the exhaust gas treatment device 9 is not particularly limited, and may be, for example, a treatment device that decomposes the special gas by plasma, or another method.

[0023] The leak inspection line 13 is a line for flowing a sampling gas for performing a gas leak inspection, which is provided by branching off from the exhaust line 2. The leak inspection line 13 is provided with a sampling gate valve 15 for introducing the sampling gas from the exhaust line 2, a sampling system switching three-way valve 21 located downstream of the sampling gate valve 15 for switching the sampling system to take in an inert gas such as nitrogen gas N2, a sampling pump 23 located downstream of the sampling system switching three-way valve 21 for sucking in the sampling gas, and a moisture meter 17 located downstream of the sampling pump 23.

[0024] The leak inspection line 13 is configured to be able to introduce a sampling gas from the exhaust line 2 when an inert gas is flowing as exhaust gas in the exhaust line 2. More specifically, when exhaust gas containing a special gas is flowing in the exhaust line 2, the sampling gate valve 15 is closed. In contrast, when an inert gas is flowing as exhaust gas not containing a special gas in the exhaust line 2, the sampling gate valve 15 is opened. In this way, by opening and closing the sampling gate valve 15, it is possible to selectively introduce an inert gas as a sampling gas from the exhaust line 2 into the leak inspection line 13.

[0025] One inlet of the sampling system switching three-way valve 21 is connected to the upstream side of the leak inspection line 13. The other inlet of the sampling system switching three-way valve 21 is connected to an inert gas introduction line. The inert gas introduction line can supply, for example, an inert gas toward the other inlet of the sampling system switching three-way valve 21. In this embodiment, an example is shown in which nitrogen gas N2 can be supplied as the inert gas from the inert gas introduction line. The inert gas supplied from the inert gas introduction line may not contain any moisture at all, or may contain a trace amount of moisture. The outlet of the sampling system switching three-way valve 21 is connected to the downstream side of the leak inspection line 13 connected to the moisture meter 17.

[0026] The moisture meter 17 is provided in the leak inspection line 13 and can measure the moisture concentration of the sample gas flowing from the exhaust line 2 to the leak inspection line 13. The moisture meter 17 generally has a higher sensitivity than an oxygen concentration meter, and a moisture meter 17 capable of measurement at the ppb (Parts-Per-Billion) level is easier to obtain than an oxygen concentration meter having the same level of sensitivity. Therefore, by configuring the exhaust gas abatement system 51 to include the moisture meter 17, it becomes easier to realize the exhaust gas abatement system 51 that can detect minute leaks, compared to a configuration in which an oxygen concentration meter is provided instead of the moisture meter 17.

[0027] The type of moisture meter 17 is not particularly limited, and may be, for example, a moisture meter of a CRDS (Cavity Ring Down Spectroscopy) type or a capacitance type. However, it is preferable that the moisture meter 17 includes a moisture-sensing unit 17a including a metal organic framework (hereinafter, referred to as "MOF"). In other words, it is preferable that the moisture meter 17 is an MOF moisture meter including MOF as a moisture-sensing material. In the MOF moisture meter, crystal or quartz is used, and glass is not used. Compared to glass, crystal or quartz is less likely to be contaminated by special gases, etc., and the analysis accuracy of the moisture meter 17 is less likely to decrease.

[0028] Below, the operation of the exhaust gas abatement system 51 of this embodiment will be explained separately for a "production state" in which the semiconductor manufacturing equipment 1 is producing semiconductors, and a "leak inspection state" in which a gas leak inspection of the exhaust line 2 is being performed.

[0029] <Current production status> The status of each component device during production is as shown in the "In Production" column of Table 1, and the gas flow is as shown by the bold arrows in Figure 2.

[0030] [Table 1]

[0031] Exhaust gas discharged from semiconductor manufacturing equipment 1 flows through exhaust line 2 to exhaust gas treatment device 9. Since sampling gate valve 15 is closed, the exhaust gas does not flow into leak inspection line 13.

[0032] The sampling system switching three-way valve 21 allows the inert gas to flow from the inert gas introduction line to the moisture meter 17, which measures the moisture concentration of the inert gas. This allows the moisture meter 17 to be continuously operated for ventilation.

[0033] <Status during leak inspection> The gas leakage inspection of the exhaust line 2 can be performed in a state where the use of the special gas in the semiconductor manufacturing equipment 1 is stopped and only an inert gas such as nitrogen gas is exhausted as an exhaust gas. More specifically, the gas leakage inspection may be performed in a state where the semiconductor manufacturing equipment 1 does not exhaust the special gas, for example, during an interval of a cycle for processing a wafer. At this time, the semiconductor manufacturing equipment 1 is in a standby state and exhausts an inert gas. At this time, an inert gas such as nitrogen gas may be supplied from the outside to the vacuum pump 5 for purging or the like (see FIG. 4). In such a case, the sampling gas flowing from the exhaust line 2 to the leakage inspection line 13 for the gas leakage inspection may be, for example, only the inert gas as the exhaust gas exhausted from the semiconductor manufacturing equipment 1, for example, only the inert gas flowing from the outside to the exhaust line 2 through the vacuum pump 5, or for example, a mixed inert gas obtained by mixing the inert gas as the exhaust gas exhausted from the semiconductor manufacturing equipment 1 and the inert gas flowing from the outside to the exhaust line 2 through the vacuum pump 5.

[0034] The gas leakage inspection may be performed in a state where the semiconductor manufacturing equipment 1 exhausts a special gas. However, the special gas may cause the moisture meter 17 to malfunction. Therefore, as described above, the gas leakage inspection is preferably performed in a state where the semiconductor manufacturing equipment 1 does not exhaust a special gas. When the gas leakage inspection is performed in a state where the semiconductor manufacturing equipment 1 exhausts a special gas, for example, it is preferable to provide an adsorption section including an adsorbent capable of physically adsorbing harmful components contained in the special gas upstream of the moisture meter 17. By providing an adsorption section including such an adsorbent, the moisture meter 17 is less likely to be damaged by the special gas. Therefore, even when the gas leakage inspection is performed in a state where the semiconductor manufacturing equipment 1 exhausts a special gas, the gas leakage inspection can be performed accurately for a long period of time.

[0035] The state of each component device during the gas leak test is as shown in the "During leak test" column of Table 1, and the gas flow is as shown by the thick arrows in Figure 3.

[0036] During the gas leakage inspection, the sampling gate valve 15, which was closed during production, is opened, and a part of the exhaust gas discharged from the semiconductor manufacturing equipment 1 passes through the sampling gate valve 15 as a sampling gas and flows into the leakage inspection line 13. The remaining exhaust gas flows into the exhaust gas processing device 9. The sampling gas that flows into the leakage inspection line 13 flows into the moisture meter 17. As described above, in this embodiment, the gas leakage inspection is performed in a state in which the semiconductor manufacturing equipment 1 discharges an inert gas. That is, the gas leakage inspection is performed in a state in which the inert gas flows into the exhaust line 2. Therefore, if there is no gas leakage, the environmental air is not introduced into the inert gas in the exhaust line 2, so the moisture meter 17 indicates a predetermined low moisture concentration according to the trace amount of moisture contained in the inert gas. On the other hand, if a gas leakage occurs, the environmental air is introduced into the inert gas in the exhaust line 2, so the moisture concentration indicated by the moisture meter 17 is higher than that in the case in which there is no gas leakage, due to the moisture contained in the environmental air. The moisture concentration may be derived using the dew point temperature.

[0037] As described above, the gas leakage inspection may be performed in a state where the semiconductor manufacturing equipment 1 exhausts a special gas. Even in this case, if a gas leakage occurs, the ambient air is introduced into the sampling gas, and the moisture concentration indicated by the moisture meter 17 is higher than that in the case where there is no gas leakage due to the moisture contained in the ambient air. However, when the gas leakage inspection is performed in a state where the semiconductor manufacturing equipment 1 exhausts a special gas, it is preferable to perform a purge process after the gas leakage inspection. In the purge process, the sampling system switching three-way valve 21 is switched to connect to the inert gas introduction line. This allows the inert gas to flow into the moisture meter 17. Next, the sampling gate valve 15 is closed. This stops the gas flow from the exhaust line 2 to the leakage inspection line 13. This state is maintained for a predetermined time. This allows the inert gas to flow into the leakage inspection line 13 for a predetermined time, and the special gas can be removed. The predetermined time may be appropriately set according to, for example, the presence or absence of an adsorbent upstream of the moisture meter 17, the adsorption capacity of the adsorbent, the shape of the piping, and the like.

[0038] <How to check for deterioration of moisture meter> Next, a description will be given of a deterioration inspection of moisture meter 17 that can be performed without stopping the operation of semiconductor manufacturing equipment 1. For example, deterioration of moisture meter 17 can be detected by monitoring whether the moisture concentration of the sample gas flowing into moisture meter 17 during a gas leak inspection is a predetermined concentration. Specifically, if the predetermined concentration is not reached even after the response time of moisture meter 17 has elapsed, it can be detected that moisture meter 17 has deteriorated.

[0039] Other methods may also be used for inspecting deterioration of moisture meter 17. For example, the moisture concentration of the inert gas flowing into moisture meter 17 may be monitored while inert gas is being supplied to moisture meter 17 from an inert gas inlet line, and deterioration of moisture meter 17 may be detected by detecting a deviation from an initial measured value before deterioration. If the error exceeds a predetermined value, span calibration can be performed with inert gas.

[0040] As described above, in the exhaust gas abatement system 51 of this embodiment, a gas leak inspection can be carried out without stopping the operation of the semiconductor manufacturing equipment 1.

[0041] In addition, between times when gas leak tests are not being performed, an inert gas such as nitrogen gas (N2) can be flowed through the moisture meter 17, allowing the moisture meter 17 to be constantly operated, enabling gas leak tests to be performed with good responsiveness. Furthermore, by measuring the moisture concentration of the inert gas, the measurement error of the moisture meter 17 can be monitored, and deterioration of the moisture meter 17 can be detected.

[0042] As described above, in this embodiment, the gas leak inspection is performed by flowing an inert gas as the sampling gas, but the gas leak inspection may be performed by flowing exhaust gas containing a special gas as the sampling gas. In such a case, as described above, the special gas can be prevented from remaining in the leak inspection line 13 by purging the leak inspection line 13 with an inert gas after the gas leak inspection. Even a small amount of special gas can cause corrosion of pipes, etc., but purging can prevent deterioration of the pipes, etc.

[0043] Next, an exhaust gas abatement system 151 as another embodiment will be described with reference to Fig. 4. The exhaust gas abatement system 151 of this embodiment differs from the above-mentioned exhaust gas abatement system 51 (see Fig. 1, etc.) in that it is configured to be able to supply nitrogen gas N2 as an inert gas from the outside to the vacuum pump 5, and that it is provided with a purification section 24 that is able to purify the nitrogen gas N2 supplied from the outside to the vacuum pump 5, but the other configurations are the same. Therefore, the above differences will be mainly described here, and a description of the same configurations will be omitted.

[0044] The gas leakage inspection of the exhaust line 2 of the exhaust gas abatement system 151 of this embodiment may be performed in a state where nitrogen gas N2 as an inert gas, which is supplied to the vacuum pump 5 from the outside and then flows into the exhaust line 2, mainly flows as a sampling gas from the exhaust line 2 to the leakage inspection line 13. Hereinafter, in this embodiment, an example of a configuration in which nitrogen gas N2 as an inert gas supplied to the vacuum pump 5 from the outside is mainly used as a sampling gas for gas leakage inspection will be described.

[0045] The purification unit 24 can purify the nitrogen gas N2 supplied to the vacuum pump 5 and flowing through the vacuum pump 5 to the exhaust line 2 before being supplied to the vacuum pump 5. As described above, the purification unit 24 of the present embodiment can purify the nitrogen gas N2 as an inert gas, but is not limited to this configuration, and may be configured to purify other inert gases other than the nitrogen gas N2. The purification unit 24 can increase the purity of the nitrogen gas N2 supplied from the outside to the vacuum pump 5. In addition, since the purification unit 24 purifies the nitrogen gas N2 before being supplied to the exhaust line 2, the moisture in the exhaust line 2 is not removed by the purification unit 24. In other words, it is possible to suppress a decrease in the accuracy of the gas leakage inspection by the moisture meter 17 due to purification by the purification unit 24. Then, the nitrogen gas N2 as an inert gas purified by the purification unit 24 is flowed through the vacuum pump 5 to the exhaust line 2, and a part of it flows into the leakage inspection line 13 as a sampling gas and is supplied to the moisture meter 17. By providing such a purification section 24, it is possible to lower the dew point temperature of the inert gas (nitrogen gas N2 in this embodiment) supplied from the outside to the vacuum pump 5, which is the reference for the gas leakage inspection. When gas leakage occurs, environmental air enters the inert gas in the exhaust line 2, that is, the nitrogen gas N2 as the inert gas supplied from the outside to the vacuum pump 5 in this embodiment, and the moisture content increases. Therefore, the dew point temperature of the inert gas in the exhaust line 2 rises. By detecting this increase in dew point temperature, it is possible to detect gas leakage. However, when the dew point temperature of the inert gas that is the reference for the gas leakage inspection is high, there is a risk that a minute leak such as 0.1 cc / min cannot be detected. This is because when the dew point temperature of the inert gas that is the reference for the gas leakage inspection is high, the amount of change in the dew point temperature with respect to a change in a given amount of moisture is smaller than when the dew point temperature is low. Therefore, it is preferable that the dew point temperature of the inert gas that is the reference for the gas leakage inspection is set low. In this way, the amount of change in the dew point temperature due to a minute leak can be increased. For this reason, in this embodiment, a refining section 24 capable of refining the nitrogen gas N2 as the inert gas supplied to the vacuum pump 5 from the outside is provided.The inert gas used in the gas leak inspection can be refined by the refining unit 24, and the dew point temperature of the inert gas, which is the standard for the gas leak inspection, can be lowered. This makes it possible to more reliably detect gas leaks, even if the leak is very small, because the change in the dew point temperature when the gas leak occurs becomes large.

[0046] The exhaust gas abatement system according to the present invention is not limited to the specific configurations shown in the above-mentioned embodiments, and various modifications and combinations are possible without departing from the scope of the claims. The exhaust gas abatement systems 51, 151 of the above-mentioned embodiments are equipped with only a moisture meter 17 to detect gas leakage in the exhaust line 2, but are not limited to this configuration. The exhaust gas abatement system according to the present invention may be equipped with, for example, an oxygen concentration meter in addition to the moisture meter 17. By providing an oxygen concentration meter in addition to the moisture meter 17, gas leakage in the exhaust line 2 can be more reliably detected based on the detection results of both the moisture meter 17 and the oxygen concentration meter. [Industrial Applicability]

[0047] The present invention relates to an exhaust gas abatement system. [Explanation of symbols]

[0048] 1: Semiconductor manufacturing equipment 2: Exhaust line 3: Isolation valve 5: Vacuum pump 7: Exhaust switching three-way valve 11: Exhaust duct 13: Leak inspection line 15: Sampling gate valve 17: Moisture meter 17a: Moisture sensitive part 21: Sampling system switching three-way valve 23: Sampling pump 24: Refining Department 51, 151: Exhaust gas abatement system

Claims

1. an exhaust line through which exhaust gas discharged from the semiconductor manufacturing equipment flows; an exhaust gas treatment device provided in the exhaust line and capable of removing harmful substances from the exhaust gas; a leakage inspection line branching off from the exhaust line; a moisture meter provided in the leak inspection line and capable of measuring the moisture concentration of sampled gas flowing from the exhaust line to the leak inspection line.

2. The exhaust gas abatement system according to claim 1 , wherein the moisture meter comprises a moisture-sensing portion including a metal-organic framework.

3. 3. The exhaust gas abatement system according to claim 1, wherein the leakage inspection line is configured to be capable of introducing the sampling gas from the exhaust line when an inert gas is flowing in the exhaust line as the exhaust gas.

4. a vacuum pump provided in the exhaust line upstream of the leak inspection line; 4. The exhaust gas abatement system according to claim 3, further comprising a purification section capable of purifying the inert gas supplied to the vacuum pump and flowing through the vacuum pump into the exhaust line before the inert gas is supplied to the vacuum pump.

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