Flow rate control system and flow rate control method

Abstract

[Problem] To accurately analyze the composition of a gas that is discharged from a semiconductor manufacturing apparatus. [Solution] This flow rate control system, which controls the flow rate of a gas flowing from a processing chamber of a semiconductor manufacturing apparatus into a container of a mass spectrometer, comprises: a flow rate control valve which is disposed in a flow path that connects the processing chamber and the container; and a control unit which adjusts the opening degree of the flow rate control valve. The control unit determines the opening degree of the flow rate control valve when analyzing the gas on the basis of a proportional relationship between an ion current value output by the mass spectrometer when the gas flows into the container and the pressure inside the container.

Description

Flow Control System and Flow Control Method

[0001] The present disclosure relates to a flow control system and a flow control method.

[0002] A flow control device that controls the flow rate of gas supplied to a semiconductor manufacturing apparatus, for example, a film forming apparatus, adjusts the opening degree of a valve provided in a flow path through which the gas flows, based on the pressure in the flow path. For example, the flow control device described in Patent Document 1 includes a first valve provided in the flow path, a second valve provided downstream of the first valve, a first pressure sensor that measures the supply pressure upstream of the first valve, a second pressure sensor that measures the holding pressure downstream of the first valve and upstream of the second valve, and a control circuit. When causing gas to flow at a predetermined control flow rate downstream of the second valve, the control circuit causes the gas to flow into the flow path in a pulsed manner, and performs feedback control on the first valve based on the output of the second pressure sensor to maintain the holding pressure at a predetermined pressure. In addition, during the period when no gas flows through the flow path, the opening degree of the second valve is adjusted based on the comparison result between the pressure drop characteristic of the supply pressure measured using the first pressure sensor and the reference pressure drop characteristic corresponding to the predetermined control flow rate.

[0003] Japanese Patent No. 7495732

[0004] The technology according to the present disclosure accurately analyzes the composition of gas discharged from a semiconductor manufacturing apparatus.

[0005] One aspect of the technology according to the present disclosure is a flow control system that controls the flow rate of gas flowing from a processing chamber of a semiconductor manufacturing apparatus into a container of a mass spectrometer, the flow control system comprising: a flow control valve disposed in a flow path connecting the processing chamber and the container; and a control unit that adjusts the opening degree of the flow control valve, wherein the control unit determines the opening degree of the flow control valve when analyzing the gas, based on the proportional relationship between the ion current value output by the mass spectrometer when the gas flows into the container and the pressure inside the container.

[0006] According to the technology of the present disclosure, the composition of gas discharged from a semiconductor manufacturing apparatus can be accurately analyzed.

[0007] This is a schematic diagram illustrating an example of the configuration of a gas recovery system for a substrate processing apparatus according to one embodiment of the technology disclosed herein. This is a graph showing an example of the relationship between the internal pressure of the container in the analyzer, the ion current value output by the mass spectrometer, and the valve operating pressure applied by the electro-pneumatic regulator to the air-driven valve. This is a graph showing an example of the relationship between the internal pressure of the container in the analyzer and the differential value of the ion current value output by the mass spectrometer. This is a flowchart showing an example of the process for determining the operating pressure at saturation. This is a diagram showing an example of the variation in primary pressure in multiple recipes executed by the film deposition apparatus. This is a diagram showing an example of the variation in primary pressure in multiple recipes executed by the film deposition apparatus. This is a diagram showing an example of the variation in primary pressure in multiple recipes executed by the film deposition apparatus. This is a flowchart showing an example of the analysis process for the composition of exhaust gas.

[0008] A quadrupole mass spectrometer (hereinafter referred to as "Q-mass") is known to be used for the analysis of the composition of gases emitted from semiconductor manufacturing equipment, such as thin-film deposition equipment (hereinafter simply referred to as "exhaust gas"), for example, for estimating the amount of a specific mass of chemical substance in the exhaust gas. The Q-mass comprises a container into which the exhaust gas flows, an ion source, a quadrupole, and a detector, with the ion source, quadrupole, and detector arranged inside the container.

[0009] In Q-mass, exhaust gas flowing into the container is ionized by an ion source, a quadrupole filters out ions of a specific mass of a chemical substance (hereinafter referred to as "specific substance"), and a detector detects the filtered ions of the specific substance and outputs an ion current value corresponding to the amount of those ions. In Q-mass, the internal pressure of the container is proportional to the amount of the specific substance in the exhaust gas flowing into the container (hereinafter referred to as "inflow gas"). Furthermore, in Q-mass, the amount of ions generated inside the container, i.e., the ion current value, is also proportional to the internal pressure of the container. Therefore, the internal pressure of the container is estimated from the ion current value output from the Q-mass detector, and the amount of the specific substance in the exhaust gas is estimated based on the estimated internal pressure of the container to analyze the composition of the exhaust gas.

[0010] By the way, in Q-mass, the flow rate of the incoming gas must be extremely small. Therefore, a needle valve is installed between the film deposition apparatus and the Q-mass container, and the flow rate of the incoming gas is controlled to a minute amount by manually adjusting the opening of the needle valve.

[0011] However, manually adjusting the opening of the needle valve is time-consuming, so there is a need to automatically control the flow rate of the Q-mass inflow gas using a controller or the like to improve the efficiency of exhaust gas analysis. In response to this, the technology disclosed herein analyzes the composition of exhaust gas using a flow control valve whose opening can be adjusted by a control unit.

[0012] Hereinafter, an embodiment of the technology relating to this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram illustrating an example of the configuration of a gas recovery system of a substrate processing apparatus according to this embodiment.

[0013] In Figure 1, the film deposition apparatus 10, which serves as a semiconductor manufacturing apparatus, comprises a processing chamber 11 for housing a wafer W, a mounting table 12 positioned inside the processing chamber 11 on which the wafer W is placed, and a shower head 13 positioned opposite the mounting table 12. Film deposition gas is supplied to the shower head 13 from a gas supply unit 14, and the shower head 13 introduces the film deposition gas into the processing chamber 11. This allows the wafer W to undergo film deposition. In the film deposition process, plasma is generated from the film deposition gas, and this plasma is used to form a film on the wafer W. However, it is also possible to form a film on the wafer W using the film deposition gas directly without generating plasma from the film deposition gas.

[0014] Furthermore, when the wafer W is subjected to the film deposition process, unreacted film deposition gas and reaction product gases are discharged as exhaust gas from inside the processing chamber 11 through the main exhaust pipe 15. An automatic pressure control valve 16 is located in the main exhaust pipe 15, and the automatic pressure control valve 16 controls the pressure of the exhaust gas from the film deposition apparatus 10.

[0015] Incidentally, since the concentration of unreacted film-forming gas and the concentration of reaction product gases change depending on the state of the film-forming process, analyzing the composition of the exhaust gas is effective in monitoring whether the film-forming process is being carried out properly. Therefore, in this embodiment, an analyzer 17 for analyzing the composition of the exhaust gas is connected to the film-forming apparatus 10.

[0016] The analysis apparatus 17 includes a branch pipe 18 (flow path) branching off from the main exhaust pipe 15 of the film deposition apparatus 10, a mass spectrometer 19 connected to the branch pipe 18, a turbomolecular pump 20, and a return pipe 21 connecting the turbomolecular pump 20 and the main exhaust pipe 15. The mass spectrometer 19 has a container 22. In the analysis apparatus 17, a portion of the exhaust gas flows into the container 22 via the branch pipe 18, and the incoming exhaust gas is discharged from the container 22 by the turbomolecular pump 20 and returned to the main exhaust pipe 15 via the return pipe 21.

[0017] The mass spectrometer 19 is, for example, a quadrupole mass spectrometer, and has an ion source, a quadrupole, and a detector (none of which are shown) arranged inside the container 22, and also has a pressure gauge 23 that measures and outputs the pressure inside the container 22. In the mass spectrometer 19, the exhaust gas flowing into the container 22 is ionized by the ion source, the quadrupole filters out ions of a specific substance, and the detector detects the filtered ions of the specific substance and outputs an ion current value corresponding to the amount of ions of the specific substance.

[0018] Furthermore, the analyzer 17 includes an air-driven valve 24 (flow control valve), a control unit 25, and an electro-pneumatic regulator 26. The air-driven valve 24 is an air-driven diaphragm valve. The air-driven valve 24 is positioned in the branch pipe 18, that is, the flow path connecting the processing chamber 11 and the container 22, and the opening degree of the air-driven valve 24 is adjusted by the valve operating pressure supplied from the electro-pneumatic regulator 26. By adjusting the opening degree of the air-driven valve 24, the degree of communication of the branch pipe 18 is adjusted, and the flow rate of exhaust gas flowing from the branch pipe 18 into the container 22 is controlled.

[0019] The control unit 25 has a memory (not shown) for storing programs and executes these programs to control the operation of each component of the analyzer 17 and the automatic pressure control valve 16. The control unit 25 also determines the valve operating pressure based on the ion current value output from the mass spectrometer 19 and the pressure inside the container 22 measured by the pressure gauge 23, and transmits the determined valve operating pressure as a command value to the electro-pneumatic regulator 26.

[0020] The electro-pneumatic regulator 26 applies a valve operating pressure corresponding to the command value to the air-driven valve 24, adjusting the opening degree of the air-driven valve 24. In other words, in the analyzer 17, the flow rate of exhaust gas (hereinafter referred to as "inflow gas") flowing into the container 22 of the mass spectrometer 19 is controlled by the control unit 25 without requiring manual intervention from the operator. These air-driven valve 24, control unit 25, and electro-pneumatic regulator 26 constitute a flow rate control system.

[0021] Figure 2 is a graph showing an example of the relationship between the internal pressure of the container 22 in the analyzer 17, the ion current value output by the mass spectrometer 19, and the valve operating pressure applied by the electro-pneumatic regulator 26 to the air-driven valve 24. Figure 3 is a graph showing an example of the relationship between the internal pressure of the container 22 in the analyzer 17 and the differential value of the ion current value output by the mass spectrometer 19.

[0022] Here, as the valve operating pressure increases, the opening degree of the air-driven valve 24 increases. Therefore, as the valve operating pressure increases, the flow rate of the incoming gas increases, and the pressure inside the container 22 also increases in proportion to the valve operating pressure. Furthermore, as the valve operating pressure increases and the flow rate of the incoming gas increases, the amount of the specific substance also increases proportionally, and the amount of ions of the specific substance generated inside the container 22, i.e., the ion current value, also increases along with the increase in the amount of the specific substance. In other words, as the valve operating pressure increases, the pressure inside the container 22, the amount of the specific substance, and the ion current value all increase, so the amount of the specific substance and the pressure inside the container 22 are proportional, and the ion current value and the pressure inside the container 22 are also proportional.

[0023] Therefore, the analysis device 17 estimates the pressure inside the container 22 based on the ion current value output from the detector of the mass spectrometer 19, and then estimates the amount of a specific substance based on the estimated pressure inside the container 22 to analyze the composition of the exhaust gas.

[0024] However, as shown in Figure 2, if the valve operating pressure becomes too high and the flow rate of the incoming gas increases too much, the amount of ions of the specific substance reaching the detector will stop increasing beyond a certain point due to the ionization capacity of the ion source and the limits of the filtering capacity of the quadrupole, and the ion current value will saturate. In this case, it can be said that the proportional relationship between the ion current value and the pressure inside the container 22 has been broken. Also, as shown in Figure 3, when the pressure inside the container 22 reaches a certain level, the ion current value saturates and the derivative of the ion current decreases.

[0025] As mentioned above, the analysis of the exhaust gas composition relies on the assumption that the ion current value in the analyzer 17 is proportional to the pressure inside the container 22. Therefore, if the ion current value no longer increases in proportion to the pressure inside the container 22, it becomes impossible to estimate the pressure inside the container 22 from the ion current value, and consequently, it becomes difficult to estimate the amount of specific substances and accurately analyze the exhaust gas composition.

[0026] Therefore, in this embodiment, when analyzing the composition of the exhaust gas, the flow rate of the incoming gas is kept within the range where a proportional relationship exists between the ion current value and the pressure inside the container 22. Specifically, the valve operating pressure at the boundary between the range where a proportional relationship exists between the ion current value and the pressure inside the container 22 and the range where a proportional relationship does not exist (hereinafter referred to as the "proportional limit between the ion current value and the pressure inside the container 22") is determined as the valve operating pressure when analyzing the composition of the exhaust gas.

[0027] Here, the valve operating pressure at the proportional limit between the ion current value and the internal pressure of the container 22 can also be called the valve operating pressure when the ion current value saturates, and will therefore be referred to as the "saturation operating pressure" hereafter (see Figure 2). Furthermore, since the opening degree of the air-driven valve 24 is adjusted by the valve operating pressure, the act of determining the valve operating pressure is nothing more than the act of determining the opening degree of the air-driven valve 24 based on the proportional relationship between the ion current value and the internal pressure of the container 22. Therefore, the act of determining the saturation operating pressure can also be said to be the act of determining the opening degree of the air-driven valve 24 corresponding to the proportional limit between the ion current value and the internal pressure of the container 22. In this embodiment, the opening degree of the air-driven valve 24 corresponding to the proportional limit between the ion current value and the internal pressure of the container 22 will be referred to as the "saturation opening degree" hereafter.

[0028] Figure 4 is a flowchart showing an example of the process for determining the operating pressure at saturation. As mentioned above, the act of determining the valve operating pressure is nothing more than the act of determining the opening degree of the air-driven valve 24. Therefore, the process in Figure 4 can also be said to be the process for determining the opening degree at saturation, and corresponds to the flow rate control method according to this embodiment. Furthermore, the process in Figure 4 is executed by the control unit 25 of the analyzer 17 based on a program stored in memory.

[0029] First, the control unit 25 obtains the pressure of the exhaust gas from the film deposition apparatus 10 during the film deposition process (hereinafter referred to as "primary pressure") from its own memory or an external storage device (not shown). At this time, since the primary pressure fluctuates during the film deposition process performed in the film deposition apparatus 10, the control unit 25 obtains the maximum value of the fluctuating primary pressure (step S41). Subsequently, the control unit 25 controls the automatic pressure control valve 16 to set the value of the primary pressure to its maximum value (step S42).

[0030] Next, the control unit 25 transmits a command value to the electro-pneumatic regulator 26 to gradually increase the valve operating pressure, and the electro-pneumatic regulator 26 applies the valve operating pressure corresponding to the command value to the air-driven valve 24. As a result, the air-driven valve 24 gradually opens (step S43), and the opening degree of the air-driven valve 24 gradually increases in response to the increase in valve operating pressure.

[0031] Next, the control unit 25 measures the ion current value output by the detector of the mass spectrometer 19 and the pressure inside the container 22 output by the pressure gauge 23 of the mass spectrometer 19 (step S44), and monitors the proportional relationship between the ion current value and the pressure inside the container 22. At this time, as long as the valve operating pressure is low, as shown in Figure 2, both the ion current value and the pressure inside the container 22 increase as the valve operating pressure increases.

[0032] Then, the control unit 25 determines whether the proportional relationship between the ion current value and the pressure inside the container 22 has reached the proportional limit of the ion current value and the pressure inside the container 22 (whether the ion current value has saturated) (step S45).

[0033] If, in step S45, it is determined that the proportional limit between the ion current value and the pressure inside the container 22 has not been reached, the process returns to step S44, and the control unit 25 continues to monitor the proportional relationship between the ion current value and the pressure inside the container 22.

[0034] On the other hand, in step S45, if it is determined that the proportional limit between the ion current value and the pressure inside the container 22 has been reached, the control unit 25 determines the valve operating pressure at this time as the "saturation operating pressure" and stores it in memory. Furthermore, the control unit 25 determines the pressure inside the container 22 at this time as the "saturation internal pressure of the container" and stores it in memory (step S46), and terminates this process.

[0035] Incidentally, the film deposition apparatus 10 performs film deposition processes for multiple recipes, but since the content of each film deposition process differs, the pattern of fluctuation in the primary pressure for each film deposition process also differs. For example, as shown in Figures 5A to 5C, the pattern of fluctuation in the primary pressure during the film deposition process for recipe A (Figure 5A), the pattern of fluctuation in the primary pressure during the film deposition process for recipe B (Figure 5B), and the pattern of fluctuation in the primary pressure during the film deposition process for recipe C (Figure 5C) are all different from each other. Therefore, the maximum value of the primary pressure during the film deposition process for each recipe is also different.

[0036] Therefore, in this embodiment, the control unit 25 sets the primary pressure value to the maximum primary pressure when the film deposition process for each of the multiple recipes is executed, and then executes the process shown in Figure 4 to determine the saturation operating pressure and saturation internal pressure. For example, when determining the saturation operating pressure and saturation internal pressure for the film deposition process of recipe A, the primary pressure value is set to the maximum value P Ａｍａｘ After setting (Figure 5A), execute the process shown in Figure 4. When determining the operating pressure and internal pressure at saturation for the film deposition process of Recipe B, set the primary side pressure to the maximum value P. Ｂｍａｘ After setting (Figure 5B), execute the process shown in Figure 4. When determining the operating pressure and internal pressure at saturation for the film deposition process of Recipe C, set the primary side pressure to the maximum value P. Ｃｍａｘ After setting it to (Figure 5C), execute the process shown in Figure 4.

[0037] Thus, the saturation operating pressure and saturation internal pressure determined in the film deposition process for each recipe are all stored in the memory of the control unit 25.

[0038] Figure 6 is a flowchart illustrating an example of the analysis process for exhaust gas composition. The process in Figure 6 is also executed by the control unit 25 of the analysis device 17 based on a program stored in memory.

[0039] First, the control unit 25 obtains the saturation operating pressure corresponding to the film deposition process recipe executed by the film deposition apparatus 10 from memory (step S61). At the same time, the control unit 25 also obtains the saturation internal pressure of the container from memory.

[0040] Subsequently, the control unit 25 transmits the saturation operating pressure as a command value to the electro-pneumatic regulator 26, and in response, the electro-pneumatic regulator 26 applies a valve operating pressure corresponding to the saturation operating pressure to the air-driven valve 24. As a result, the opening degree of the air-driven valve 24 is set to the saturation opening degree (step S62), and the opening degree of the air-driven valve 24 is maintained at the saturation opening degree until this process is completed.

[0041] Next, the control unit 25 measures the ion current value output by the detector of the mass spectrometer 19 (step S63), and determines whether or not an abnormality has occurred in the internal pressure of the container 22 (step S64). Specifically, it is determined whether or not the estimated internal pressure of the container 22 based on the measured ion current value exceeds the acquired saturated internal pressure of the container.

[0042] When it is determined in step S64 that the estimated internal pressure of the container 22 exceeds the acquired saturated internal pressure of the container, it is considered that a malfunction or clogging of the air-driven valve 24 has occurred, so the control unit 25 terminates this process. On the other hand, when it is determined in step S64 that the estimated internal pressure of the container 22 does not exceed the acquired saturated internal pressure of the container, the control unit 25 estimates the amount of the specific substance based on the estimated internal pressure of the container 22 and analyzes the composition of the exhaust gas in real time (step S65).

[0043] Next, the control unit 25 determines whether or not the analysis of the exhaust gas composition is completed, for example, whether or not the execution time of the exhaust gas composition analysis exceeds a predetermined execution time (step S66).

[0044] When it is determined in step S66 that the execution time of the exhaust gas composition analysis does not exceed the predetermined execution time, the process returns to step S63. On the other hand, when it is determined in step S66 that the execution time of the exhaust gas composition analysis exceeds the predetermined execution time, the control unit 25 terminates this process.

[0045] According to the present embodiment, when analyzing the composition of the exhaust gas, the opening degree of the air-driven valve 24 is set to the saturated opening degree, so that a proportional relationship between the ion current value and the internal pressure of the container 22 is established. Thereby, the internal pressure of the container 22 can be accurately estimated from the ion current value, and further, the amount of the specific substance is estimated based on the estimated internal pressure of the container 22, so that the composition of the exhaust gas can be accurately analyzed.

[0046] In the present embodiment, the opening degree of the air-driven valve 24 is set to the saturation opening degree, so that until the proportional limit between the ion current value and the internal pressure of the container 22 is reached, the flow rate of the inflow gas can be increased to raise the amount of the specific substance, and the amount of ions generated inside the container can be increased. Furthermore, since the saturation operation pressure is determined based on the ion current value actually measured by the mass spectrometer 19 and the internal pressure of the container 22, it is not necessary to determine the saturation operation pressure with a margin relative to the catalog data of the quadrupole filtering performance of the air-driven valve 24, and the quadrupole filtering performance can be utilized to the limit. Thereby, the amount of ions detected by the detector of the mass spectrometer 19 can be increased, and the composition analysis of the exhaust gas can be performed more accurately.

[0047] In the present embodiment, when analyzing the composition of the exhaust gas, the control unit 25 sets the opening degree of the air-driven valve 24 via the electropneumatic regulator 26 based on the saturation operation pressure acquired from the memory, so that the flow rate control of the inflow gas is performed automatically without requiring manual work by an operator. Thereby, the efficiency of exhaust gas analysis can be improved.

[0048] While preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist thereof.

[0049] For example, in the analyzer 17, the air-driven valve 24 is used to control the flow rate of the exhaust gas flowing into the interior of the container 22, but other types of valves may be used. For example, a valve whose opening degree is adjusted by a motor may be used. In this case, in the process of FIG. 4, the control unit 25 stores the accumulated rotation speed of the motor from the start of the valve opening operation when it is determined that the proportional limit between the ion current value and the internal pressure of the container 22 has been reached. Further, in the process of FIG. 6, the control unit 25 adjusts the opening degree of the valve by rotating the motor of the valve by the stored accumulated rotation speed.

[0050] Further, the semiconductor manufacturing apparatus whose exhaust gas composition is analyzed by the analyzer 17 is not limited to a film forming apparatus, and for example, the composition of the exhaust gas of an etching apparatus may be analyzed by the analyzer 17.

[0051] This application claims priority based on Japanese Patent Application No. 2025-066658, filed on April 15, 2025, and all of its contents are incorporated herein by reference.

[0052] 10 Film deposition apparatus 11 Processing chamber 17 Analytical apparatus 18 Branch pipe 19 Mass spectrometer 22 Container 24 Air-driven valve 25 Control unit 26 Electro-pneumatic regulator

Claims

1. A flow control system for controlling the flow rate of gas flowing from a processing chamber of a semiconductor manufacturing apparatus to a container of a mass spectrometer, comprising: a flow control valve arranged in a flow path connecting the processing chamber and the container; and a control unit for adjusting the opening degree of the flow control valve, wherein the control unit determines the opening degree of the flow control valve when analyzing the gas based on the proportional relationship between the ion current value output by the mass spectrometer when gas flows into the container and the internal pressure of the container.

2. The flow control system according to claim 1, wherein the control unit monitors the proportional relationship between the ion current value and the pressure inside the container while gradually increasing the opening of the flow control valve, and determines the opening of the flow control valve at the boundary between the range in which the proportional relationship between the ion current value and the pressure inside the container is established and the range in which the proportional relationship between the ion current value and the pressure inside the container is not established as the opening of the flow control valve when analyzing the gas.

3. The flow rate control system according to claim 2, wherein the control unit determines that the proportional relationship between the ion current value and the pressure inside the container no longer holds when the ion current value is saturated.

4. The flow rate control system according to claim 2, wherein when the control unit obtains the proportional relationship between the ion current value and the pressure inside the container, the value of the pressure of the gas discharged from the processing chamber is set to the maximum value of the pressure of the gas discharged from the processing chamber when processing is performed in the semiconductor manufacturing apparatus.

5. The flow control system according to claim 1, wherein the mass spectrometer is a quadrupole mass spectrometer and has a pressure gauge for measuring the pressure inside the container.

6. The flow control system according to claim 1, wherein the flow control valve is an air-driven diaphragm valve, and the opening degree of the flow control valve is adjusted by the valve operating pressure controlled by an electro-pneumatic regulator.

7. The flow control system according to claim 6, wherein the electro-pneumatic regulator applies to the flow control valve a valve operating pressure corresponding to the determined opening degree of the flow control valve.

8. The flow control system according to claim 1, wherein the control unit maintains the determined opening degree of the flow control valve when analyzing the gas flowing into the container.

9. The flow rate control system according to claim 2, wherein the semiconductor manufacturing apparatus performs processing of a plurality of recipes, and the control unit sets the value of the gas pressure discharged from the processing chamber to the maximum value of the gas pressure discharged from the processing chamber when the processing of the plurality of recipes is performed, and monitors the proportional relationship between the ion current value and the pressure inside the container.

10. A flow rate control method for controlling the flow rate of gas flowing from a processing chamber of a semiconductor manufacturing apparatus to a container of a mass spectrometer, wherein the opening degree of a flow control valve arranged in a flow path connecting the processing chamber and the container when analyzing the gas is determined based on the proportional relationship between the ion current value output by the mass spectrometer when the gas flows into the container and the internal pressure of the container.

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