System with gas analysis device and method for controlling the same

Abstract

A system (100) having an analysis device (1) that analyzes a component contained in a gas (9) is provided. The analysis device has a filter (25) that selectively passes the component contained in the gas, a detector (26) that detects the component that has passed through the filter, and a first control device (36) configured so that the detector (26) detects a low-abundance isotope 21Ne that is a main component, i.e., neon, contained in the gas and does not detect a high-abundance isotope 20Ne.

Description

Technical Field

[0001] This invention relates to a system with a gas analysis device and its control method. Background Technology

[0002] Japanese Patent Application Publication No. 2006-145295 discloses a real-time GC / MS system for detecting and analyzing trace gases. This system captures and stores trace gas samples, retains the sample, and delivers it to a GC column for separation. The sample is separated into components by the GC column, and all components are analyzed in real-time using a mass spectrometer. In this system, a gas flow distribution system stores the sample from the sample bearing carrier gas using a miniature accumulator. The carrier gas is then used to deliver the sample to the gas chromatography column, facilitating real-time separation of the sample into components and delivery of these components to the mass spectrometer for detection, analysis, or testing of trace gases.

[0003] Japanese Patent Application Publication No. 2021-154240 discloses a rare gas (e.g., krypton) recovery system capable of recovering and purifying rare gases from waste gas discharged from a semiconductor manufacturing apparatus containing 100 ppm to 1% (preferably with a maximum volume concentration of less than 500 ppm) of rare gases. The system comprises: an impurity removal unit that removes specified impurities from the waste gas containing rare gases; a rare gas separation membrane assembly that separates the waste gas into concentrated waste gas and waste gas with a low rare gas concentration, wherein the concentrated waste gas contains a high concentration of rare gas (krypton) that is higher than the rare gas concentration of the waste gas containing rare gases after the specified impurities have been removed; and a rare gas adsorption unit that selectively adsorbs rare gases from the concentrated waste gas.

[0004] Japanese Patent Application Publication No. 2019-141752 discloses a laser gas recirculation system and method for obtaining purified gas from exhaust gas discharged from an excimer laser oscillator after the removal of specified impurities. This laser gas recirculation system is used to obtain purified gas with high-purity neon as the main component by removing specified impurities from exhaust gas discharged from an excimer laser oscillator or the oscillation chamber of an excimer laser. The system includes: a separation membrane device for membrane separation of the gas to be treated using a rare gas for excitation, excluding neon; and an impurity removal device for removing specified impurities from the treated gas that permeates (or does not permeate) through the separation membrane device.

[0005] Japanese Patent Application Publication No. 2005-123528 discloses an ArF excimer laser device for exposure with two mounting stages, comprising: an oscillation laser device having an oscillation chamber containing a first laser gas comprising F2 gas, Ar gas, and a first buffer gas; and an amplification device having an amplification chamber containing a second laser gas comprising F2 gas, Ar gas, and a second buffer gas, and amplifying and emitting a laser beam emitted from the oscillation laser device. The ArF excimer laser device for exposure with two mounting stages operates at an oscillation frequency of 4 kHz or higher. In the ArF excimer laser device for exposure with two mounting stages, the first buffer gas is He gas or a mixture of He gas and Ne gas, and the second buffer gas is composed of Ne gas. Summary of the Invention

[0006] There are many processes that use gases containing a major component and trace components at levels of a few percent to ppm or sub-ppm (ppb) relative to that major component for processing, and there are also many applications for determining the content of trace components with high precision. Gas lasers are one such field, including helium-neon lasers, argon lasers, krypton lasers, carbon dioxide lasers, and excimer lasers. In particular, excimer lasers, which use mixed gases such as rare gases and halogens to generate laser beams, are widely used in machining, semiconductor manufacturing, and ophthalmic treatment. Beyond gas lasers, in order to improve the yield and precision of products in processes using gases, there is a growing desire to monitor the composition of gases used in the process (including gases supplied to the process, gases generated in the process, gases discharged from the process, and gases generated as byproducts, hereinafter referred to as process gases), and to manage the process execution equipment (processing equipment) and process parameters based on this information.

[0007] Furthermore, from the perspectives of resource conservation and the circular economy, the demand for the reuse of gases used, discarded (exhausted), or containing impurities in processes is constantly increasing. In such processes, there is a strong desire to monitor the composition of gases at each stage of the recovery and / or regeneration process. Conventional GC / MS devices for measuring trace components in gases are large, time-consuming, and consume carrier gases such as helium. Therefore, there is a need for a device and method that can perform high-precision on-site analysis of trace components using a simple mechanism.

[0008] One aspect of the invention is a system having an analytical apparatus for analyzing components contained in a gas. The analytical apparatus includes: a filter that selectively allows components contained in the gas to pass through; a detector that detects components that have passed through the filter; and a first control device configured to set the filter such that the detector detects at least one isotope of a first component contained in the gas that is of low abundance, but does not detect high abundance isotopes of the first component. The first control device may also set the filter such that the detector detects only one isotope of the low abundance of the first component.

[0009] When the first component is a major component or one of the major components of the gas being analyzed, its detection intensity is several to tens, hundreds, or even more times greater than that of trace components, making it difficult to determine the first component and trace components with the same level of precision. On the other hand, the low-abundance isotopes of the first component are fractions, tens of fractions, or hundreds of fractions or less compared to the high-abundance isotopes of the first component. Therefore, conventionally, high-abundance isotopes have become the primary targets for analysis, while low-abundance isotopes are either buried by noise and difficult to measure, or are not a focus of attention in the analysis.

[0010] In this invention, at least one isotope of the first component and low-abundance isotopes of the first component are selected by the detector in such a way that high-abundance isotopes of the first component are not selected (i.e., high-abundance isotopes of the first component are not measured / detected), or at least one isotope of low-abundance isotopes of the first component is selected by the detector and measured (detected) by the detector. Therefore, trace components, which are fractions, tens of fractions, or hundreds of fractions or less relative to the main component, as well as the first component, can be measured with the same or similar accuracy. Thus, components contained in a gas, including trace components, can be measured with high precision, enabling high-precision analysis of the gas composition. Furthermore, since it is not necessary to detect signals with very high intensity corresponding to the main component, detector degradation can be suppressed.

[0011] The controller may include a second control device (second coordination function, second coordination device, second coordination control device) that selects a second component contained in the gas through a filter at a resolution lower than that of any isotope among the low-abundance isotopes of the first component, and detects it through a detector. When the second component is present in trace amounts, the detection intensity of the second component can be increased by reducing the filter resolution for components with high intensity. Therefore, even when the content of the second component is less than that of the low-abundance isotopes of the first component, the second component, as a trace component, and the first component, as a major component, can be determined with the same or similar accuracy using the low-abundance isotopes of the first component.

[0012] The analytical apparatus may have an ionization device located upstream of a filter to ionize components contained in the gas. The ionization device can be set with an ionization energy to suppress the ionization of a first component. This suppresses saturation of the ion source within the analytical apparatus due to the ionization of the high abundance of the first component, and also suppresses the influence of other trace components containing impurities on the determination. The analytical apparatus may include a third control device that sets the ionization energy of the ionization device to suppress the ionization of the first component. An example of the ionization device includes a filament that releases thermionic electrons.

[0013] The system may have: a chamber configured to temporarily hold gas at a location upstream of the analytical apparatus; and an exhaust system that controls the amount of gas flowing into the chamber. Furthermore, the exhaust system may be configured to maintain the pressure P within the chamber at the following condition (1).

[0014] 0.005Pa < P < 0.05Pa…(1)

[0015] The lower limit of condition (1) can be 0.008 and the upper limit can be 0.03.

[0016] Most mass analysis devices, which filter gas based on its mass-to-charge ratio (m / z), control the pressure of the gas introduced into them to a pressure of 10 MPa. -3 The system suppresses the influence of high-abundance components by adjusting the pressure (Pa) below a certain level. In this system, isotopes with low abundance of the primary component are measured, while isotopes with the highest abundance of the primary component are not measured. Furthermore, the ionization of the primary component is suppressed. Therefore, when the pressure within the chamber increases, the content of both the primary and trace components within the chamber increases, but the increase in the primary component does not significantly affect the measurement. Thus, by increasing the pressure within the chamber, the sensitivity of the trace component measurement (detection) is increased due to the increased content of the trace component.

[0017] Examples of the first component are inert gases such as neon (Ne) and argon (Ar). Inert gases have high ionization energies. Therefore, it is easy to set an ionization energy that suppresses the ionization of the main component and does not easily hinder the ionization of trace components. Furthermore, even if the pressure inside the chamber is increased, only the inert components increase, thus reducing the possibility of degradation of the analytical device due to filament oxidation. The filter may include a quadrupole filter.

[0018] The system may include: a processing device, from which process gas flows in or is discharged; a supply device, which supplies process gas from at least one of the input, intermediate, and output of the processing device to the analysis device as the gas to be analyzed; and a management device, which manages the processing device and / or the process performed by the processing device based on the analysis results of the analysis device.

[0019] Another aspect of the invention is a control method for a system having an analytical apparatus for analyzing components contained in a gas. The analytical apparatus includes: a filter that selectively allows components contained in the gas to pass through; and a detector that detects the components that have passed through the filter. The method includes: a controller of the analytical apparatus selecting, through the filter, any one of the low-abundance isotopes of a first component contained in the gas, and detecting it through the detector. The controller can control the analytical apparatus to select only any one of the low-abundance isotopes of the first component through the filter and detect it through the detector. The method may further include: the controller selecting, in a reduced-resolution state, a second component contained in the gas through the filter and detecting it through the detector.

[0020] The analytical apparatus may also have an ionization device that ionizes components contained in the gas at a location upstream of the filter, and the method may further include a controller setting the ionization energy to suppress the ionization of the first component. The system may have: a chamber that temporarily holds the gas at a location upstream of the analytical apparatus; and an exhaust system that controls the amount of gas flowing into the chamber, and the method may further include a controller maintaining the pressure P in the chamber at the condition described above (1).

[0021] The system may include: a processing unit, from which process gas flows in or out; and a supply unit that supplies process gas from at least any one of the input, intermediate, and output of the processing unit to the analysis unit. The system management unit may include: managing the processing unit and / or the process based on the analysis results from the analysis unit.

[0022] Another aspect of the invention is a method for analyzing components contained in a gas using an analytical apparatus. The analytical apparatus includes: a filter that allows components contained in the gas to pass selectively; and a detector that detects the components that have passed through the filter. The method includes: selecting any one of the low-abundance isotopes of a first component contained in the gas, while excluding high-abundance isotopes of the first component, and detecting them using the detector.

[0023] Another aspect of the invention is a control program (program product) for a system having an analytical apparatus for analyzing components contained in a gas, which can be provided by recording on a suitable recording medium. The analytical apparatus includes: a filter that selectively allows components contained in the gas to pass through; and a detector that detects the components that have passed through the filter. The control program includes the following commands: the controller of the analytical apparatus selects, through the filter, any one of the low-abundance isotopes of a first component contained in the gas, excluding high-abundance isotopes of the first component, and detects them through the detector. Attached Figure Description

[0024] Figure 1 This is a block diagram showing an outline of a system including a gas analysis device.

[0025] Figure 2 This is an example showing the results obtained from measuring a gas.

[0026] Figure 3 This is a graph showing how the detection intensity varies with ionization energy.

[0027] Figure 4 This is a graph showing how the detection intensity varies depending on the chamber pressure.

[0028] Figure 5 This is an example showing the results obtained from measuring a gas.

[0029] Figure 6 This is a flowchart illustrating an overview of the system's control. Detailed Implementation

[0030] exist Figure 1The outline structure of the process monitoring system 100 is shown as an example of a system including a gas analysis device 1. The system 100 shown is a system that manages a gas regeneration unit (recirculation unit, processing unit) 101 and a gas regeneration process 101p performed by the gas regeneration unit 101. The system 100 includes: a supply unit 102 that switches or supplies gas 109a, which is a process gas supplied to the gas regeneration unit 101 for process 101p, gas 109b, processed and output by process 101p, and gas 109c being processed in process 101p, as a gas (sample gas) 9 to the gas analysis device 1, either in a switching or parallel manner; and a management unit (process controller) 105 that manages the gas regeneration unit 101 and / or process 101p with reference to the analysis results of the gas analysis device 1. In this example, the supply device 102 includes switching valves 103a, 103b and 103c, which switch gases 109a, 109b and 109c to the gas analyzer 1.

[0031] The processing apparatus that performs the process of allowing the process gas 109, which is the object of analysis in the gas analysis device 1, to flow in or out is not limited to the gas regeneration device 101. The processing apparatus can be an apparatus used in semiconductor processes to perform processes including the formation of various films or layers on a substrate or the etching of the substrate, such as CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition). The processing apparatus is not limited to processes related to semiconductor manufacturing; it can be an apparatus that performs processes of stacking various thin films using optical components such as lenses and filters as substrates, an apparatus that performs the mixing, regeneration, and recovery of gases used in semiconductor manufacturing, or a processing apparatus that processes gases for other purposes.

[0032] Japanese Patent Application Publication No. 2019-141752 disclosed an example of a gas regeneration apparatus 101. This example of gas regeneration apparatus 101 is a device (laser gas recirculation system) that obtains purified gas (after removing specified impurities) from exhaust gas discharged from an excimer laser oscillator. Regarding an example of the exhaust gas (process gas) 109a to be treated, it is described that: the main component is neon, and rare gases (krypton, xenon, argon) account for 1 to 10% of the total amount, preferably 1 to 8%. Impurities in the exhaust gas include, for example, CF4, N2, and He, and it is assumed that the concentration of CF4 in the exhaust gas is in the range of 1 ppm to 500 ppm.

[0033] Furthermore, as an example of a laser gas whose main component is neon, Japanese Patent Application Publication No. 2005-123528 discloses a mixed gas containing 3.5% argon (Ar), 10 ppm (0.001%) xenon (Xe), and the remainder neon (Ne), i.e., 96.499% neon (Ne). Therefore, when it is desired to monitor the composition of the gas being processed and the gas being recycled by using the apparatus 101 for processing such a gas, it is desirable to be able to quantitatively, online, and in real time monitor trace components or impurities present at concentrations (mixing ratios) relative to the main component at the % to ppm level or below using the gas analysis apparatus 1.

[0034] The process monitoring system 100 using the gas analysis apparatus 1 in this example monitors the gas 9, which is the object of analysis, in real time and provides highly reliable measurement results (analysis results), thereby enabling innovative process control. As an example, the gas analysis apparatus 1 functions as a comprehensive solution platform. This platform aims to significantly improve production capacity and maximize yield in semiconductor chip manufacturing by enabling real-time monitoring of the gas composition used in various processes or steps related to semiconductor manufacturing. Furthermore, by combining it with systems for gas generation, recovery, and regeneration, it also functions as a platform for reconsidering processes to maximize resource utilization efficiency from the perspectives of resource conservation and a circular economy.

[0035] Typically, the gas analysis device 1 in this example is a very small quality analysis device that can be directly connected to or assembled into the device being analyzed. Furthermore, the gas analysis device 1 can be equipped with standard protocols primarily used in semiconductor manufacturing process equipment, such as the Ethernet control automation (EitherCat) protocol 51, thereby enabling integration into process equipment control systems such as the process monitoring system 100.

[0036] Gas analysis apparatus 1 is an apparatus for analyzing components contained in a gas (sample gas) 9. Gas analysis apparatus 1 includes: a chamber 10 configured to temporarily hold the sample gas 9 supplied from the process flow side by a supply device 102; an ionization device 22 configured to generate ions (ion stream) 17 in the sample gas 9; a filter 25 configured to selectively allow components contained in the gas to pass through; and a detector 26 configured to detect components that have passed through the filter. An example of gas analysis apparatus 1 is a mass spectrometer (MS). The filter 25 may include a filter unit (typically a mass filter, in this example a quadrupole filter) 25 that filters (selects, filters, switches) the ionized sample gas (sample gas ions) 17 supplied from the ionization device 22 according to the mass-to-charge ratio. The detector 26 may also be a detector that detects the filtered ions (ionic strength, ionic current).

[0037] The gas analysis apparatus 1 also includes: a vacuum container (shell) 40 housing a filter unit 25 and a detector 26; and an exhaust system 60 capable of maintaining a suitable negative pressure condition (vacuum condition) inside the shell 40 and the chamber 10 connected to the shell 40. The chamber 10 is important as it controls the conditions (pressure) of the sample gas 9 flowing into the gas analysis apparatus 1, but in order to enable real-time measurements, the chamber 10 may have a minimum capacity, for example, 1 to several tens of cm³. 3 Or 1 to several cm 3 A container or buffer with a capacity of about 100 mm can also be formed from a piping that also serves as a supply device 102.

[0038] The exhaust system 60 in this example includes a turbomolecular pump (TMP) 61 and a Roots pump (dry pump) 62. This exhaust system 60 controls the internal pressure of the chamber 10 via a housing 40 containing a filter 25 and a detector 26. The dry pump 62 can also be provided as an option. Other types of pumps can also be used in the exhaust system 60, and the system can perform exhaust in one stage or in multiple stages (three or more stages). The exhaust system 60 can have an exhaust path 65 that allows exhaust from the sample chamber 10 around the housing 40, and can also control the internal pressure of the sample chamber 10 by separately guiding sample gas 9 into the sample chamber 10 from the flow rate of the gas flowing for filtration. When analyzing discarded or exhausted gases, a large amount of sample gas 9 can be introduced from the process into the sample chamber 10 relative to the amount of gas (ion quantity) supplied to the filter 25, thereby providing a gas analysis device 1 capable of real-time monitoring of the state (changes) of the process 101p.

[0039] One example of filter 25 is a mass filter, comprising four cylindrical or quadrupole electrodes (hyperquads) 25a whose inner surfaces are processed into hyperboloids to form a hyperbolic electric field for filtering based on the mass-to-charge ratio. The quadrupole mass 25 can also be a filter that arranges multiple, for example, nine cylindrical electrodes in a matrix (array) to form multiple pseudo-hyperbolic electric fields. As for detector 26, examples include Faraday cups (FC), secondary electron multipliers (SEMs), etc. Detector 26 can be used in combination or interchangeably. Detector 26 can also be other types such as channel electron multipliers (CEMs), microchannel plates (MPs), etc.

[0040] Ionization apparatus 22 includes an electron ionization device (filament, EI ion source) 23, which ionizes (electron ionizes) the sample gas 9 supplied from process 101p via gas supply device 102 and chamber 10 by electron bombardment (thermal electrons). The EI ion source 23 is typically located at 10... -3 It operates under high vacuum below Pa, but in this example, when the main component of sample gas 9 is an inactive gas, even at 10 Pa... -2 It can also operate under low vacuum of Pa or above. The gas analysis device 1 may also include one or more lenses (ion lenses, electrostatic ion lenses) 24, which are configured to guide the ionized gas 9 as an ion stream (ion beam) 17 to the filter 25.

[0041] The gas analysis device 1 includes a controller (control box, control module) 30 for controlling each module of the analysis device 1, and an interface device 50 for external communication. The controller 30 includes computer resources such as a CPU and memory, and controls the gas analysis device 1 by loading and executing a program (program product) 39. The program 39 can be provided by recording on a computer-readable medium. The interface device 50 includes a power input I / F 52 and a communication I / F 51 compliant with Ethernet control automation.

[0042] The control module (controller) 30 may have the functions of controlling the ionization device 22 (ionization control device) 31, controlling the mass filter 25 (filter control device) 32, detecting arriving ions (ion current) via the detector 26 (detector control device) 33, and controlling the pressure of the chamber 10 by controlling the exhaust system 60 (pressure control device) 34. These control devices 31-34 may have the function of controlling each device (unit) as the controlled object to maintain the set value or condition. In addition, the controller 30 may also have the function of coordinating the control of multiple devices (units) of the gas analysis device 1 to perform a specified measurement (coordination control device) 35. The coordination control device may include, for example, the function of setting a specified condition for the filter 25 by the controller 30 and using the detector 26 to detect the component selected according to the condition. The ionization control device 31 controlling the ionization device 22 may include the function of an ionization energy control device (filament control device) that controls the filament current and / or voltage supplied to the filament 23.

[0043] exist Figure 2 The diagram shows an example of measuring a process gas (first mixed gas) 109b regenerated by the gas regeneration process 101p of the gas regeneration apparatus 101 described above as sample gas 9. This first mixed gas 109b is ArF gas, and as an example, it contains 3.5% argon (Ar), 10 ppm (0.001%) xenon (Xe), and 96.499% neon (Ne). Figure 2 The diagram shows an example of the results obtained when the first mixed gas 109b was used as the sample gas and measured using an existing mass spectrometer (MS). The results of the mass analysis were obtained as an indicator of the intensity in terms of mass-to-charge ratio (m / z).

[0044] Neon, argon, xenon, helium, krypton, and other elements are contained together in a chemically stable, inert gas. Neon is an element with atomic number 10. As a stable isotope, 20Ne (mass-to-charge ratio 20) accounts for 90.48%, 21Ne (mass-to-charge ratio 21) accounts for 0.27%, and 22Ne (mass-to-charge ratio 22) accounts for 9.25%. Argon is an element with atomic number 18. As a stable isotope, 40Ar (mass-to-charge ratio 40) accounts for 99.6%, 38Ar (mass-to-charge ratio 38) accounts for 0.063%, and 36Ar (mass-to-charge ratio 36) accounts for 0.337%. Xenon is an element with atomic number 54. As a stable isotope, 132Xe with a mass-to-charge ratio of 132 accounts for 26.9%, 131Xe with a mass-to-charge ratio of 131 accounts for 21.2%, 130Xe with a mass-to-charge ratio of 130 accounts for 4.07%, 129Xe with a mass-to-charge ratio of 129 accounts for 26.4%, 128Xe with a mass-to-charge ratio of 128 accounts for 1.91%, and 126Xe with a mass-to-charge ratio of 126 accounts for 0.089%.

[0045] When the mixture 109b was measured using conventional mass analysis equipment, neon accounted for more than 96% of the components contained in the mixture 109b, and the concentration (content) of xenon was about six digits lower than that of neon (10). -6 Therefore, it is difficult to simultaneously detect neon and xenon under the same conditions using a detector. In particular, it is difficult to simultaneously determine each component with high precision. Furthermore, the ion current becomes enormous when measuring neon, making it difficult to ensure the detector's lifespan. Moreover, even if it were possible to simultaneously measure argon, the ionization of argon is expected to be hindered because the ionization of neon, which constitutes a large portion of the gas, would saturate the ionization device. Therefore, it is considered impossible to measure such a sample gas using a mass spectrometry-type gas analysis device.

[0046] exist Figure 3 The diagram shows the pressure within chamber 10 set to 10. -2This is an example of measuring the intensity of argon obtained by changing the ionization energy (thermal electron energy) of the ionization device 22 to determine the mixed gas 109b. In conventional mass analysis apparatuses, since the mass spectra registered in existing databases, such as NIST, are measured at 70 eV, the ionization energy in the ionization device is set to 70 eV. However, it is known that in this case, when the ionization energy is increased, the number of argon ions increases, but the increase tends to peak near the ionization energy of 37 eV, and then the intensity of argon decreases when the ionization energy is increased toward 70 eV. Therefore, it is believed that when the ionization energy exceeds 37 eV, the interior of the ionization device 22 becomes saturated due to the ionization of neon, which accounts for a large portion of the mixed gas 109b, thus hindering the ionization of argon. Therefore, it is known that, as with mixed gas 109b, in a gas where the main component (first component) accounts for several tens of percent, suppressing the ionization of the main component can promote the ionization of other components.

[0047] exist Figure 4 The diagram shows the relationship between the pressure in chamber 10 and the measured intensity of argon when the ionization energy is set to 35 eV during the measurement of mixed gas 109b. Increasing the pressure within the chamber increases the amount of argon introduced into filter 25, leading to an increase in the intensity measured by detector 26. This measurement verifies that even when the ionization energy is set lower than that set in conventional mass analysis devices, the measured intensity of argon (detection intensity) increases approximately proportionally to the chamber pressure.

[0048] These components, being inert gases, have relatively high ionization energies: neon has an ionization energy of approximately 21.6 eV, argon approximately 15.8 eV, and xenon approximately 12.1 eV. Therefore, it can be seen that ionization in ionization device 22 at energies exceeding the ionization energies of each component has the advantage of increasing the ion quantity; however, it also has the drawback of excessively increasing the ion quantity. In particular, when the ionization energy of the main component (first component) in a gas such as the mixed gas 109b in this example is high, by reducing the ionization energy in ionization device 22 to a predetermined range, it is possible to discover an ionization energy condition that can suppress the ionization of the main component and have almost no effect on the ionization of trace components. For example, the target value of the ionization energy of ionization device 22 can be set to a value that is insufficient or inadequate for the main component (a value indicating ionization but not to the extent that all molecules are ionized), and sufficiently high compared to the ionization energy of trace components.

[0049] In this example, the ionization control device 31 of the controller 30 of the gas analysis apparatus 1 may also include a function to maintain the ionization energy of the ionization device 22 at a set value 22a that meets the above conditions. The controller 30 may also have a third control device 31a that sets the ionization energy of the ionization device 22 to a value 22a that suppresses the ionization of the first component. When the above-mentioned mixed gas 109b is used as the sample gas 9 for analysis, the third control device 31a may also set the ionization energy set value 22a to 35 eV or a value around that.

[0050] The coordination control function 35 of the controller 30 includes a first control device 36 configured to set the filter 25 such that the filter 25 detects at least one isotope of the low abundance isotopes of the first component contained in the gas (sample gas) 9, which is the object of measurement, but does not detect the high abundance isotopes of the first component. The first control device 36 includes a first coordination function (first coordination control device) that selects at least one isotope of the low abundance isotopes of the first component through the filter 25 and detects it through the detector 26. The first control device 36 may also be configured to set the filter 25 such that the detector 26 detects only one isotope of the low abundance isotopes of the first component.

[0051] The controller 30 may further include a second control device 37 that sets the filter 25 such that the detector 26 detects trace amounts of the second component contained in the sample gas 9 at a resolution lower than that of the low-abundance isotope of the selected first component. The second control device 37 includes a second coordination function (second coordination control device) for selecting trace amounts of the second component at low resolution through the filter 25 and detecting them through the detector 26.

[0052] The controller 30 may also include a pressure control device 34, which maintains the pressure P in the chamber 10 under the following conditions via the exhaust system 60.

[0053] 0.005PaP<0.05Pa…(1)

[0054] The lower limit of condition (1) can be 0.008 and the upper limit can be 0.03.

[0055] exist Figure 5The following is a simulation of the results obtained by measuring the ArF gas (first mixed gas) 109b as sample gas 9 using the gas analysis apparatus 1 described above. First, the filter 25 is set by the first control device 36 such that the filter 25 selects at least one isotope of the first component (neon) as the main component (neon) and the low-abundance isotope of the first component (neon) in the sample gas 9, in a manner that does not select the high-abundance isotope (20Ne) of the first component (neon), i.e., does not measure (detect) the high-abundance isotope (20Ne) of the first component. In this example, only 21Ne is selected, and the ion flow that has passed through the filter 25 is measured (detected) by the detector 26 at this time. The first control device 36 can set the filter 25 to prevent 20Ne from passing through (not setting the time of passage), or it can disconnect the detector 26 when 20Ne passes through the filter 25.

[0056] Through the first control device 36, the gas analyzer 1 can select 0.27% (10) of the intensity of neon with an intensity of 20Ne via the filter 25. -4 Instead of selecting 20Ne, 21Ne is detected by detector 26. Therefore, neon, which constitutes the main component of sample gas 9 and accounts for over 90% of the total, can be detected at an intensity close to that of a trace component present in the ppm level. Thus, in the gas analysis apparatus 1, the components contained in gas 9, including both the main component and trace components, can be determined with high precision, enabling high-precision analysis of the components of gas 9, including trace components. Furthermore, in the gas analysis apparatus 1, it is not necessary to detect signals with very high intensity corresponding to the main component, thus suppressing the degradation of detector 26.

[0057] In the gas analysis apparatus 1 of this example, argon, which has the second highest mixing ratio in ArF gas 109b, can also be detected by the detector 26 by the first control device 36 through the filter 25, selecting only the low-abundance isotope 36Ar and not the high-abundance 40Ar. Therefore, in the gas analysis apparatus 1, argon, which has the second highest content after neon in the sample gas 9, can also be detected with the same or similar intensity as other trace components.

[0058] Furthermore, the gas analyzer 1 sets the pressure P inside the chamber 10 to a pressure one order of magnitude or more higher than that of conventional filament-type mass analyzers via the pressure control function 34, thereby increasing the amount of sample gas 9 flowing into the gas analyzer 1. On the other hand, the ionization energy setting 22a is reduced to 35 eV via the ionization energy control function 31a of the ionization control device 31, thereby suppressing the ionization of neon isotopes, which are the main components of the sample gas 9. Therefore, the amount of ions of trace components other than neon can be relatively increased, thereby improving the detection sensitivity of trace components. In addition, the main component of the mixed gas (ArF) 109b to be measured is neon, which is an inactive gas, and it is believed that even if the flow rate is increased, it will hardly affect the lifespan of the filament 23. In addition, as impurities, they may originate from the chamber 10 or the supply device 102 for the chamber 10, etc. However, by increasing the inflow of gas 9 into chamber 10, the amount of impurities originating from gas regeneration device 101 or process 101p can be increased, thereby also having the advantage of improving the detection sensitivity of trace components as elements of management device 101 or process 101p.

[0059] In the gas analysis apparatus 1, the second control device 37 uses the filter 25 to select trace amounts of the second component (xenon) contained in the sample gas 9 from the process gas (ArF gas) 109b at a resolution lower than that for selecting a low-abundance isotope (21Ne) of the first component (neon), and detects it via the detector 26. The second control device 37 controls the filter 25 and the detector 26 to detect only the isotope 21Ne at a resolution of 1 AMU or higher, within the scanning unit (resolution, mass-to-charge ratio m / z) of the gas analysis apparatus 1 when measuring neon. Conversely, when measuring xenon, the second control device 37 controls the filter 25 and the detector 26 to detect over a wide range of multiple isotopes containing xenon. The second control device 37 can also control the filter 25 to use the set (integral) of the measurement results from the detector 26 detected at a resolution of 1 AMU or higher as the xenon detection result. In the xenon measurement, the second control device 37 can also set the filter 25 so that the filter 25 detects all stable isotopes, namely 132Xe, 131Xe, 130Xe, 129Xe, 128Xe and 126Xe, as the xenon intensity, and detects it through the detector 26.

[0060] Through these controls and settings, in the gas analysis device 1, xenon present in the first mixed gas (ArF gas) 109b at the ppm level can be detected with an intensity approximately the same as or close to that of nearly 100% neon and a few percent argon. Therefore, the gas analysis device 1 can simultaneously and in real time measure, analyze, and monitor the trace and main components in the process gas 109b. Similarly, it can be seen that even if the process gas 109 contains impurities at the ppm or sub-ppm (ppb) level in addition to the components of the predetermined mixed gas (ArF gas), such as helium (He), methane (CH4), nitrogen (N2), oxygen (O2), carbon dioxide (CO2), carbon tetrafluoride (CF4), etc., in addition to the components of the predetermined mixed gas (ArF gas), these impurities can be measured with high accuracy and in real time, and can be used for the management of process 101p.

[0061] Furthermore, the system 100 may also include a calibration device 70, which measures a standard gas (test gas) 71 containing a known concentration under conditions pre-set for the gas analyzer 1 as described above, and calibrates (corrects) the detection intensity of trace components such as argon and xenon, as well as the detection intensity of neon, which is the main component. The controller (control module) 30 of the gas analyzer 1 may also include a mixing ratio output device (calculation function, calculation device, output device) 38, which stores the calibration result 38a and, when measuring the sample gas 9 on-site, calculates the mixing ratio of trace components based on the ratio of the detection intensity of other components to the detection intensity of neon, which is the main component (first component), based on the calibration result 38a. With the gas analyzer 1, trace components or impurities can be determined with high precision on-site. Therefore, the measurement results (analysis results) of the gas analyzer 1 can be used for the control, management, and monitoring of process 101p. The function of calculating the mixing ratio can also be installed in an external device such as the process controller 105.

[0062] The gas to be measured in the gas analysis apparatus 1 can also be other gases, such as KrF gas. As a gas used for xenon lasers, it is known to contain krypton instead of xenon, or to contain both xenon and krypton (KrF gas). Krypton (Kr) is an element with atomic number 36. As a stable isotope, 86Kr with a mass-to-charge ratio of 86 accounts for 17.3%, 84Kr with a mass-to-charge ratio of 84 accounts for 57%, 83Kr with a mass-to-charge ratio of 83 accounts for 11.5%, 82Kr with a mass-to-charge ratio of 82 accounts for 11.6%, 80Kr with a mass-to-charge ratio of 80 accounts for 2.25%, and 78Kr with a mass-to-charge ratio of 78 accounts for 0.35%. Therefore, in the system 100 where a mixed gas containing approximately ppm to a few percent of Kr is measured, the gas analysis apparatus 1 in this example can, in the same way as in the case of a mixed gas containing xenon, accurately detect and analyze other trace impurities, including them.

[0063] The analysis results from the gas analyzer 1 can be supplied to the process controller 105 via the communication interface 51 of the interface device 50, such as Ethernet control automation technology. The analysis results can also be provided to other external devices monitoring the process 101p via the cloud. The process controller 105 may have computer resources such as a CPU and memory, and can be run via a control program (program product) 108. An example of the process 101p controlled and / or monitored by the process controller 105 is a process executed by the processing unit 101. Gases used in semiconductor processes flow into or out of the processing unit 101. Process gases 109a-109c, at least any one of the inputs, intermediates, and outputs of the processing unit 101, can be supplied to the gas analyzer 1 via the supply device 102 for analysis, and the processing unit 101 and the process 101p can be controlled and monitored based on the results.

[0064] exist Figure 6 Example of a control process (control method, control program) in a process monitoring system 100 including a gas analysis device 1 is shown. In step 81, at least any one of the input, intermediate, and output process gases 109a-109c of the processing device 101 is selected by the supply device 102 and supplied to the gas analysis device 1 as sample gas 9. The process gas flows into or out of the processing device 101. In step 82, the gas analysis device 1 begins gas analysis. First, in step 83, the gas analysis device 1 sets the ionization energy 22a in the ionization device 22 to a value suitable for the gas 9 to be measured by the ionization control device (third control device) 31a. In this example, when measuring a mixed gas containing neon as the main component (first component), the ionization energy 22a, which can suppress the ionization of neon, is set to, for example, 35 eV. Next, in step 84, the gas analyzer 1 sets the pressure of chamber 10 to a higher range than the normal condition (1) by means of pressure control device 34, and increases the supply of trace components to the gas analyzer 1.

[0065] In step 86, if neon, which has the highest content and is the main component (first component), is measured, in step 87, the first control device 36 uses filter 25 to select 21Ne, which is a low-abundance isotope, instead of selecting 20Ne, a high-abundance isotope (20Ne is not measured), and detects it through detector 26. Multiple low-abundance isotopes can be selected and detected, but if it is desired to detect the main component with the same intensity as trace components, especially extremely small amounts at the ppm level, only one (limited to one) of the low-abundance isotopes can be selected through filter 25 and detected through detector 26.

[0066] In step 88, if the argon content is the second highest, in step 89, the first control device 36 selects 36Ar as a low-abundance isotope through the filter 25 instead of 40Ar as a high-abundance isotope (40Ar is not measured), and detects it through the detector 26.

[0067] In step 90, when measuring xenon (the second component) as a trace component, in step 91, the second control device 37 uses filter 25 to select xenon isotopes at a resolution lower than that used to select low-abundance isotopes such as 21Ne or 36Ar as the main component, and detects them using detector 26. For example, all xenon isotopes, namely 126Xe, 128Xe, 129Xe, 130Xe, 131Xe, and 132Xe, are selected by filter 25 and detected by detector 26, and their sum (integral value) is taken as the measured value of xenon.

[0068] In step 92, the gas analyzer 1 can output the mixing ratio to the process controller 105 based on the calibration result 38a via the mixing ratio output device 38. Alternatively, information on impurities such as helium (He), methane (CH4), nitrogen (N2), oxygen (O2), carbon dioxide (CO2), and carbon tetrafluoride (CF4) at the ppm or sub-ppm level obtained during the gas analysis can also be output to the process controller 105. In step 93, the process controller 105, acting as a process management device, manages the processing unit (gas regeneration unit) 101 or the process (gas regeneration process) 101p implemented by the processing unit based on the measurement results (analysis results) of the gas analyzer 1.

[0069] As explained above, as an embodiment of the present invention, a rapid analytical method for analyzing impurities in Ne gas used for excimer lasers using a gas analysis apparatus 1 can be provided. The Ne gas used for excimer lasers must have concentrations of Ar, Xe, Kr, etc., within a certain range. Furthermore, components unsuitable for the laser, such as N2, O2, and CO, must be kept below a certain concentration. Moreover, considering analysis time, space, and carrier gas consumption, it is desirable to directly sample the Ne gas into a mass spectrometer to determine impurities in the Ne gas in real time, without using a gas chromatograph (GC) or similar instrument.

[0070] Therefore, it is desirable to improve the analytical sensitivity of Xe and impurities (such as N2, O2, CO, CO2, etc. in Ne gas). In the gas analysis apparatus 1, the pressure control device 34 is used to increase the sensitivity compared to normal (e.g., 10). -3 (with Pa as the upper limit) introduce more gas into the mass analysis chamber 10 (e.g., 10). -2(Approximately Pa). As a result, more impurities are introduced into the quality analysis chamber.

[0071] In particular, impurities such as N2 and O2, besides originating from Ne gas, are always present in a certain amount as background components within the mass analysis chamber. Therefore, it is necessary to distinguish between impurities originating from the chamber and those originating from Ne gas. Introducing as much Ne gas as possible into the mass analysis chamber increases the amount of Ne gas-derived impurities relative to the background in the vacuum, thereby enabling more sensitive determination of impurity concentrations. Furthermore, Ne gas is an inert gas, so even if more gas than usual is introduced into the mass analysis chamber 10, the damage to the filament 23 is minimal.

[0072] Next, the ionization energy is controlled by the ionization energy control device (third control device) 31a. If too much Ne gas is introduced into the mass analysis chamber 10, the ion source will become saturated with Ne ions, which will adversely affect the accuracy of the impurity concentration analysis. Therefore, the ionization energy (the energy at which the hot electrons released from the filament 23 collide with molecules and atoms) is adjusted to suppress the ionization of Ne. In this example, 35 eV is used. The energy required for Ne to ionize is much higher than that of other atoms and molecules, so by adjusting the ionization energy, other atoms / molecules can be fully ionized while only the ionization of Ne is suppressed.

[0073] Furthermore, if there is no possibility that the mass region of other components overlaps with that of the analyte (e.g., Xe), the determination is performed by the second control device 37 in a manner that prioritizes sensitivity over resolution. Specifically, by broadening the peak, a higher ion intensity can be obtained.

[0074] Furthermore, the ionization of Ne (20Ne) is suppressed by the first control device 36, and the intensity of the Ne peak used for quantification is reduced by several orders of magnitude by using the isotope 21Ne. In excimer laser gases, it is necessary to maintain the concentrations of Xe, Ar, Kr, etc., in the Ne gas within a certain concentration range. However, to maintain this concentration range, it is essential to be able to monitor these concentrations with high precision. By using the first control device 36, the intensity of the Ne peak used for quantification can be reduced by several orders of magnitude, thereby making the ratios of the Ne / Ar / Xe peaks (e.g., in the case of ArF laser gases) close. Similarly, with Ar, the intensity of the Ar peak used for quantification can be reduced by several orders of magnitude by using the isotope 36Ar. By carefully selecting the isotopes of the components contained in the gas, their peak intensities can be made close, thereby improving the accuracy of concentration calculations.

[0075] Furthermore, by detecting the low-abundance isotopes 21Ne and 36Ar and calculating the concentration of each component, it is possible to avoid detecting ions with high peak currents, such as 20Ne and 40Ar. Therefore, the degradation of the detector 26 can be mitigated, thereby providing a gas analysis device 1 that can be used for a long period.

[0076] Furthermore, the mixing ratio output device 38 allows the concentration (mixing ratio) to be calculated based on the ratio of the peak intensity of Ne to the peak intensities of other components, always using the peak intensity of Ne as a reference. Typically, impurity concentrations are calculated directly from peak intensities. In this case, the peak intensity varies depending on the amount of gas introduced into the mass spectrometer; therefore, in quantification within a system measuring changes in ambient pressure, the amount of gas introduced into the mass spectrometer needs to be kept constant. In this method, by calculating the concentration based on the Ne peak value, even slight changes in pressure within the mass spectrometer can be eliminated.

[0077] Furthermore, while the example of using a quadrupole mass filter as filter 25 was described above, filter 25 can be any filter that can select, filter, and switch on / off components containing molecules and / or atoms based on the mass-to-charge ratio m / z, such as TOF, ion trap, or Wien filter, or other types.

[0078] Furthermore, while specific embodiments of the present invention have been described above, those skilled in the art will be able to conceive of various other embodiments and modifications without departing from the scope and spirit of the present invention. Such other embodiments and modifications are the subject of the following claims, which define the present invention.

Claims

1. A system having an analytical device that analyzes components contained in a gas. The analytical device has: A filter that allows components contained in the gas to pass through selectively; and The detector detects the components that have passed through the filter. The analytical device also has: A first control device is configured to set the filter such that the detector detects at least one isotope of a low abundance of the first component, which is a first component contained in the gas, with a first intensity, but does not detect high abundance isotopes of the first component. The second control device is configured to set the filter such that the detector detects a trace amount of a second component contained in the gas relative to the first component at a second intensity; as well as An output device that, without detecting high-abundance isotopes of the first component, determines the mixing ratio of the second component relative to the first component based on the first intensity of at least one of the low-abundance isotopes of the first component and the second intensity of the second component, which is present in trace amounts relative to the first component.

2. The system according to claim 1, wherein, The first control device is configured to set the filter such that the detector detects only any one of the low-abundance isotopes of the first component at the first intensity.

3. The system according to claim 1 or 2, wherein, The second control device is configured to set the filter such that the detector detects the second component contained in the gas at a resolution lower than that of any of the isotopes selected from the low abundance of the first component.

4. The system according to any one of claims 1 to 3, The analytical apparatus further includes an ionization device located upstream of the filter to ionize components contained in the gas, the ionization device being set with an ionization energy to suppress the ionization of the first component.

5. The system according to any one of claims 1 to 3, wherein, The analytical device also has: An ionization device that ionizes components contained in the gas at a location upstream of the filter; and A third control device sets the ionization energy of the ionization device to suppress the ionization of the first component.

6. The system according to claim 4 or 5, wherein, The ionization device includes a filament that releases thermionic electrons.

7. The system according to any one of claims 1 to 6, further comprising: A chamber configured to temporarily hold the gas at a location upstream of the analytical apparatus; and An exhaust system that controls the amount of gas flowing into the chamber, the exhaust system being configured to maintain the pressure P in the chamber at the condition that 0.005 Pa < P < 0.05 Pa.

8. The system according to any one of claims 1 to 7, wherein, The first component contains an inactive gas.

9. The system according to any one of claims 1 to 8, wherein, The filter includes a quadrupole filter.

10. The system according to any one of claims 1 to 9, comprising: The process gas flows into or exits the processing device; A supply device that supplies the process gas, at least any one of the input, intermediate, and output of the processing device, to the analysis device; as well as A management device that manages the processing device or the process executed by the processing device based on the analysis results of the analysis device.

11. A control method, which is a control method for a system having an analytical apparatus for analyzing components contained in a gas. The analytical device has: A filter that allows components contained in the gas to pass through selectively; and The detector detects the components that have passed through the filter. The method includes: The controller selects at least one isotope of a low abundance of the first component contained in the gas through the filter, but does not select a high abundance isotope of the first component, and detects it with a first intensity through the detector. The controller selects a second component contained in the gas in trace amounts relative to the first component via the filter, and detects it at a second intensity via the detector; and Without detecting high-abundance isotopes of the first component, the controller calculates the mixing ratio of the second component relative to the first component based on the first intensity of at least one of the low-abundance isotopes of the first component and the second intensity of the second component, which is present in trace amounts relative to the first component, and outputs the mixing ratio.

12. The method according to claim 11, Selecting at least one isotope from the low-abundance isotopes of the first component via the filter and detecting it at the first intensity via the detector includes: The filter selects only one isotope from the low-abundance isotopes of the first component, and the detector detects it at the first intensity.

13. The method according to claim 11 or 12, Detection by the detector at the second intensity also includes: The controller selects the second component contained in the gas through the filter at a resolution lower than that of any isotope among the low-abundance isotopes of the first component, and detects it through the detector at the second intensity.

14. The method according to any one of claims 11 to 13, wherein, The analytical apparatus has an ionization device located upstream of the filter to ionize the components contained in the gas. The method further includes: the controller setting the ionization energy to suppress the ionization of the first component.

15. The method according to any one of claims 11 to 14, It also has: A chamber, located upstream of the analytical apparatus, temporarily holds the gas; and An exhaust system that controls the amount of gas flowing into the chamber. The method also includes the controller maintaining the pressure P within the chamber under the following conditions: 0.005Pa < P < 0.05Pa.

16. The method according to any one of claims 11 to 14, wherein, The first component contains an inactive gas.

17. The method according to any one of claims 11 to 16, wherein, The system has: The process gas flows into or exits the processing device; as well as A supply device that supplies the process gas from at least one of the inputs, intermediates, and outputs of the processing device to the analysis device. The method includes: the system's management device managing the processing device or the process implemented by the processing device based on the analysis results of the analysis device.

18. A method for analyzing components contained in a gas using an analytical apparatus. The analytical apparatus includes: A filter that allows the components contained in the gas to pass through selectively; as well as The detector detects the components that have passed through the filter. The method includes: The filter selects at least one isotope of a low-abundance isotope of the first component contained in the gas, while excluding high-abundance isotopes of the first component, and detects them at a first intensity by the detector. The filter selects a second component contained in the gas in trace amounts relative to the first component, and the detector detects it at a second intensity; and Without detecting high-abundance isotopes of the first component, the mixing ratio of the second component relative to the first component is determined based on the first intensity of at least one of the low-abundance isotopes of the first component and the second intensity of the second component, which is present in trace amounts relative to the first component, and the mixing ratio is output.

19. A control program for a system having an analytical apparatus for analyzing components contained in a gas. The analytical device has: A filter that allows components contained in the gas to pass through selectively; and The detector detects the components that have passed through the filter. The control program contains commands that cause the controller of the analysis device to perform the following processes: The filter selects at least one isotope of a low-abundance isotope of the first component contained in the gas, while excluding high-abundance isotopes of the first component, and detects them at a first intensity by the detector. The filter selects a second component contained in the gas in trace amounts relative to the first component, and the detector detects it at a second intensity. as well as Without detecting high-abundance isotopes of the first component, the mixing ratio of the second component relative to the first component is determined based on the first intensity of at least one of the low-abundance isotopes of the first component and the second intensity of the second component, which is present in trace amounts relative to the first component, and the mixing ratio is output.

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