System having gas analysis device and control method for same

Abstract

Provided is a system (100) having a preparation device (10) for supplying, to a gas analysis device (1), a portion (19) of a mixed gas obtained by mixing a first gas (9) containing a first trace component to be measured in a first main component and a second gas (18) containing a second component serving as an internal standard sample in a second main component. A controller (30) of the gas analysis device includes: a first control device (36) for selecting, by means of a filter (25), a first trace component contained in the mixed gas and detecting the same by means of a detector (26); and a second control device (37) for selecting either an isotope having a low abundance ratio of the second component by means of the filter and detecting the same by means of the detector.

Description

System having gas analyzer and control method thereof

[0001] The present invention relates to a system having a gas analyzer and a control method thereof.

[0002] Japanese Patent Application Laid-Open No. 2003-060209 describes a method for adding a low concentration of impurities with high precision. An a-Si film is formed on a glass substrate while adding an impurity (boron), and then nickel is added, followed by heat treatment and laser light irradiation to obtain a crystalline silicon film. In this case, diborane gas diluted to 100 ppm with hydrogen is supplied for only 15 seconds after the start of a-Si film formation. By doing this, even if diborane gas diluted to a relatively high concentration of 100 ppm, where the concentration is stable, is supplied, the average concentration of the boron in the a-Si film can be kept at approximately 1E12 atoms / cm. ２ In this way, the boron concentration can be set accurately to a low concentration of about 1E11 atoms / cm ２ ~1E13atoms / cm ２ By setting the threshold voltage of the TFT to 0.5 V, the threshold voltage of the TFT can be controlled with high precision within a range of about several volts.

[0003] Japanese Patent Application Laid-Open Publication No. 2009-031201 discloses a technology aimed at solving the problem that, in the case of a mass spectrometer connected to a liquid chromatograph, multiple sample components are introduced into the mass spectrometer successively in a short period of time, making it difficult to introduce an internal standard sample and perform mass calibration. To achieve the above object, in a mass spectrometry method for measuring the exact mass number of ions, which combines a liquid chromatograph as an analytical means for separating a target component in a sample with a mass spectrometer as a means for sequentially ionizing the separated sample components and continuously acquiring mass spectra of the corresponding components, an internal standard sample of known mass number for mass calibration is mixed with a mobile phase solvent using a liquid chromatograph pump, and the internal standard sample is introduced into the mass spectrometer by continuous or pulse introduction, and the mass spectrum from the internal standard sample is referenced to perform mass calibration of the mass spectrum of the target component by the internal standard method.

[0004] Special gases for semiconductor manufacturing, which are mixtures of carrier gases and trace amounts of material gases, are known as material gases used in semiconductor manufacturing. Conventionally, such gases are prepared by gas manufacturers and delivered to factories or facilities using them in cylinders or other containers. There is a demand for on-site regeneration of gases used in semiconductor processes and for blending them according to the progress of the process. In response to this demand, there is a demand for accurate, real-time measurement of gases containing trace amounts of components on the order of ppm or less at the process site (e.g., manufacturing plant). Furthermore, in applications where process management is possible, there is a demand for management of the equipment (processing equipment) that executes the process and the process (parameter management) based on the measurement results.

[0005] One aspect of the present invention is a system including an analyzer for analyzing components contained in a gas. The system includes a preparation device (gas preparation device, mixed gas generation device) that supplies a gas (mixed gas) containing a component to be measured to the analyzer. The preparation device supplies a portion of the mixed gas to the analyzer, the mixed gas being a mixture of a first gas containing a first major component and a first trace component to be measured, and a second gas containing a second major component and a second component at a predetermined ratio. The analyzer includes a filter that selectively passes components contained in the mixed gas, a detector that detects the components that have passed through the filter, and a controller that controls the setting of the filter. The controller includes a first control device (first cooperative control device, function) configured to set the filter so that the detector detects the first trace component contained in the mixed gas, and a second control device (second cooperative control device, function) configured to set the filter so that the detector detects at least one isotope of the second component that is less abundant than the first major component.

[0006] The second control device may be configured to set a filter so that only one of the isotopes of the second component that is less abundant is detected by the detector. A typical second gas may be a standard gas, and the preparation device may be configured to supply a mixed gas containing the standard gas as the second gas, in which the second component is contained in the second main component as an internal standard sample.

[0007] When detecting a trace component of a first gas, if a detector is used to detect both the first major component and the first minor component, the concentration difference is too great, making it difficult to calculate the concentration of the minor component. Furthermore, the excessive concentration difference can lead to excessively high detection intensities, resulting in rapid detector degradation. By detecting the second component of a second gas containing the second component at a predetermined ratio, e.g., a concentration similar to that of the first minor component, it is possible to reduce the concentration difference between the first minor component and the second minor component during detection. However, it is not easy to generate a gas containing a trace amount of the second component at a ratio on the order of ppm or less, similar to the component to be measured. Furthermore, calibration reference gases (standard gases, calibration gases) containing trace amounts of internal standard samples are not commercially available, and individually preparing such standard gases is neither easy nor economical.

[0008] In the system of the present invention, the second control device uses a filter to select at least one of the isotopes of the second component having a low abundance ratio as the measurement target (detection target) for calibration, instead of the second component (an isotope of the second component having a high abundance ratio) contained in the standard gas as the original internal standard sample, i.e., the isotope of the second component having a high abundance ratio is not detected, and the selected isotope is detected by the detector. In this system, a gas containing the second component at a concentration on the order of 100% or more is used as the standard gas, and trace components of the measurement target on the order of ppm or less can be detected by the detector with sensitivity comparable to that of the reference sample.

[0009] An example of the second gas in this system is a standard gas (calibration gas) containing argon. For example, the abundance ratio of Ar36, which has a low abundance ratio, is 3.4 × 10 of Ar40, which has a high abundance ratio. －３Therefore, if a gas containing 10% Ar is used as the standard gas, by detecting Ar36 instead of Ar40, it can be used as a calibration gas containing 340 ppm of trace components for calibration. Furthermore, by using a filter to selectively detect the first trace component, which has a similar concentration, and the isotope of the second component, which has a low abundance ratio, not only can detection accuracy be ensured but also damage to the detector can be suppressed.

[0010] Furthermore, the preparation device of this system can set the amounts of the first and second gases to be mixed within a range that allows for precise control by supplying a portion of the mixed gas to the analyzer. In other words, to accurately detect trace components, it is desirable to avoid significant changes in the filter and detector conditions, including pressure, and to supply a trace amount of mixed gas, e.g., 1 sccm or less, to the analyzer. It is not easy to accurately supply a trace amount of mixed gas containing the first trace component. This system solves this problem by controlling the inflow rates of the first and second gases at a flow rate that allows for precise mixing to generate a mixed gas, and then supplying a portion of the mixed gas to the analyzer in an amount appropriate for analysis. The preparation device may include a first flow controller, e.g., a first mass flow meter, that controls the inflow rate of the first gas, a second flow controller, e.g., a second mass flow meter, that controls the inflow rate of the second gas, and a third flow controller that controls the inflow rate to the analyzer.

[0011] The analytical device may have an ionization device that ionizes components contained in the mixed gas upstream of a filter. The filter may include a quadrupole filter. The system may have a processing device into which a process gas flows or is discharged, a supply device that supplies at least one of an input, intermediate, and output process gas of the processing device to the preparation device as a first gas, and a management device that manages the processing device and / or a process performed by the processing device based on the analysis results of the analytical device.

[0012] Another aspect of the present invention is a method for controlling a system having an analyzer that analyzes components contained in a gas. The method includes the following steps: supplying a portion of a mixed gas, which is a mixture of a first gas containing a first trace component to be measured in a first major component and a second gas containing the second component at a predetermined ratio in a second major component, to the analyzer as the gas to be measured; selecting the first trace component contained in the mixed gas using a filter of the analyzer by a controller and detecting it with a detector of the analyzer; and selecting at least one of the isotopes of the second component that is less abundant using a filter of the analyzer and detecting it with a detector of the analyzer as an alternative to detecting the first major component, instead of the isotope of the second component that is more abundant. By omitting the detection of the first major component with a high abundance ratio and further omitting the detection of the isotope of the second component with a high abundance ratio, it is possible to continuously detect the first trace component and the isotope of the second component with a low abundance ratio that serves as its calibration component in real time with high accuracy and while suppressing detector deterioration.

[0013] The supplying step may include controlling an inflow rate of the first gas with a first flow rate controller, controlling an inflow rate of the second gas with a second flow rate controller, and controlling an amount of a portion of the mixed gas supplied to the analytical device with a third flow rate controller.The system may include a processing device into which the process gas flows or is discharged, and a supply device that supplies at least one of the input, intermediate, and output process gases of the processing device to the preparation device as the first gas, and the method may include a system management device that manages the processing device and / or a process being performed by the processing device based on the analysis result of the analytical device.

[0014] Another aspect of the present invention is a control program (program product) for a system including an analyzer for analyzing components contained in a gas, which may be provided as a recording medium. The system includes a preparation device that supplies a portion of a mixed gas obtained by mixing a first gas containing a first component to be measured that is contained in a trace amount in a first major component and a second gas containing the second component at a predetermined ratio (concentration) in a second major component to the analyzer. The analyzer includes a filter that selects and passes components contained in the mixed gas, and a detector that detects components that have passed through the filter. The program includes instructions for a controller to select the first trace component contained in the mixed gas using the filter and detect it using the detector, and to select at least one isotope of the second component that is less abundant using the filter and detect it using the detector, instead of the first major component, instead of the isotope of the second component that is more abundant using the filter and detect it using the detector.

[0015] Fig. 1 is a block diagram showing an overview of a system including a gas analyzer. Fig. 2 shows an example of a result of measuring a gas. Fig. 3 shows an example of a result of measuring a mixed gas. Fig. 4 is a flowchart showing an overview of the control of the system. MODE FOR CARRYING OUT THE INVENTION

[0016] 1 shows a schematic configuration of a process monitoring system 100 as an example of a system including a gas analyzer 1. The illustrated system 100 is a system that manages a gas generator 101 and a gas generation process 101p executed by the gas generator 101. The system 100 includes a supply device 102 that switches between, or in parallel with, gas 109a supplied to the process 101p of the gas generator 101, gas 109b processed and output by the process 101p, and gas 109c being processed in the process 101p, and supplies these gases to the gas analyzer 1 as a gas to be analyzed (sample gas) 9; and a management device (process controller) 105 that manages the gas generator 101 and / or the process 101p by referring to the analysis results of the gas analyzer 1. The supply device 102 in this example includes switching valves 103a, 103b, and 103c that switch between gases 109a, 109b, and 109c and supply them to the gas analyzer 1.

[0017] The processing equipment that performs a process into or out of which the process gas to be analyzed by the gas analyzer 1 flows is not limited to the gas generator 101. The processing equipment may be an equipment for performing a process in a semiconductor process, such as a process for forming various types of films or layers on a substrate or etching a substrate, for example, a process including CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition). The processing equipment is not limited to a process related to semiconductor manufacturing, but may also be an equipment for performing a process for depositing various types of thin films on optical components such as lenses and filters as substrates, an equipment for performing regeneration and / or recovery, not limited to blending gases used in semiconductor manufacturing, or a processing equipment for handling gases for other purposes.

[0018] An example of the gas generator 101 is a device that generates a semiconductor gas (semiconductor special material gas) such as low-concentration diborane gas (disclosed in JP 2003-060209 A) by mixing a main component (first main component, atmospheric gas, carrier gas) with a trace amount of a material gas (first trace component) in a factory where semiconductor manufacturing equipment is installed. Many types of trace components contained in the material gas are known, such as monosilane, arsine, phosphine, and diborane. If the semiconductor gas to be generated is diborane gas, an example of the generator 101 may be a device that generates the semiconductor gas from pure hydrogen as a carrier gas (first main component) and high-concentration diborane gas as the first trace component, for example, a gas containing 3% diborane in hydrogen. In this case, an example of the gas 109b supplied from the gas generator 101 is a gas containing 100 to several hundred ppm of diborane (B2H6) in hydrogen. When monitoring the components of the gas generated by such a gas generator (blender) 101, it is desirable to use the gas analyzer 1 to quantitatively, on-site, and in real time monitor trace components (diborane in this example) or impurity components present at concentrations (mixing ratios) on the order of ppm or less relative to the main component (hydrogen, H2 in this example). Therefore, the process monitoring system 100 includes a preparation device 10 for continuously supplying the component to be analyzed (measured) to the gas analyzer 1 along with an internal standard sample of approximately the same concentration.

[0019] The process monitoring system 100 using the preparation device (gas preparation device, gas mixing device) 10 and gas analyzer 1 of this example performs real-time monitoring of trace components contained in the gas 9 to be analyzed and provides highly reliable measurement results (analysis results), thereby providing innovative process control. The preparation device 10 allows the gas analyzer 1 to, for example, monitor trace components contained in gases used in each process or step related to semiconductor manufacturing in real time while continuously calibrating them using an internal standard method. This serves as a total solution platform aimed at dramatically improving throughput and maximizing yield rates in semiconductor chip manufacturing. Furthermore, by combining it with a system for gas generation, recovery, and regeneration, it also serves as a platform aimed at reviewing each process from the perspectives of resource conservation and circular economy, and maximizing resource utilization efficiency. The gas analyzer 1 of this example is typically a very small mass spectrometer and can be directly connected to or incorporated into the device to be analyzed. Furthermore, the gas analyzer 1 can be equipped with a standard protocol that is primarily used in semiconductor manufacturing process equipment, such as the EtherCat (registered trademark) protocol 51, and can be integrated into the process equipment control system 100.

[0020] The preparation device 10 mixes the sample gas 9 supplied from the process side by a supply device 102 with a standard gas (reference gas, calibration gas) 18 supplied from a standard gas source (reference gas source) 80 in a predetermined ratio, and supplies a portion of the mixture to the gas analyzer 1 as the gas 19 to be analyzed. The gas analyzer 1 includes a chamber 29 configured to temporarily hold the mixed gas 19 supplied from the preparation device 10, an ionizer 22 configured to generate ions (ion flow) 27 of the gas 9 to be measured, a filter 25 configured to select and pass components contained in the gas, and a detector 26 configured to detect the components that have passed through the filter. An example of the gas analyzer 1 is a mass spectrometry detector (mass spectrometer, MS). The filter 25 may include a filter unit (typically a mass filter, a quadrupole filter in this example) 25 that filters (selects, sorts, turns on and off) the ionized sample gas (sample gas ions) 27 supplied from the ionization device 22 according to their mass-to-charge ratio. The detector 26 may be a detector that detects the filtered ions (ion intensity, ion current).

[0021] The gas analyzer 1 further includes a vacuum container (housing) 40 that houses the filter unit 25 and the detector 26, and an exhaust system 60 that can maintain an appropriate negative pressure condition (vacuum condition) inside the housing 40 and the chamber 29 connected to the housing 40. The chamber 29 is important as a place to control the condition (pressure) of the gas 19 to be analyzed that flows into the gas analyzer 1, but its volume should be kept to a minimum, for example, 1 to several tens of cm, to enable real-time measurement. ３ Or 1 to several cm ３ The gas analyzer 1 may be a container or buffer having a capacity of about 1000 kJ / L, or may be formed by a part of the piping connecting the preparation device 10 and the gas analyzer 1.

[0022] The exhaust system 60 of this example includes a turbomolecular pump (TMP) 61 and a roots pump (dry pump) 62, and controls the internal pressure of the chamber 29 via the housing 40 in which the filter 25 and the detector 26 are built. The dry pump 62 may be provided as an option. Other types of pumps may be used in the exhaust system 60, and the system may be a single-stage exhaust system or a multi-stage exhaust system with three or more stages. The exhaust system 60 may also serve to exhaust the mixed gas 17 prepared in the preparation apparatus 10.

[0023] An example of the filter 25 is a mass filter, which includes four cylindrical or columnar electrodes (HyperQuad) 25a whose interiors are hyperbolic to form a hyperbolic electric field for filtering based on mass-to-charge ratio. A quadrupole-type mass filter 25 may have a large number of cylindrical electrodes, for example, nine, arranged in a matrix (array) to form multiple pseudo-hyperbolic electric fields. Examples of the detector 26 include a Faraday cup (FC) and a secondary electron multiplier (SEM). These detectors 26 may be used in combination or in a switchable manner. The detector 26 may also be of other types, such as a channel electron multiplier (CEM) or a microchannel plate (MP).

[0024] The ionization device 22 includes an electron ionization device (filament, EI ion source) 23 that ionizes (electron ionization) the gas 19 to be analyzed, which is supplied from the preparation device 10 via a chamber 29, by electron impact (thermal electrons). －３ It can be operated at a high vacuum of 10 Pa or less. －２The gas analyzer 1 can operate in a low vacuum of 100 Pa or higher. The gas analyzer 1 may include one or more lenses (ion lenses, electrostatic ion lenses) 24 configured to direct the ionized gas 19 as an ion flow (ion beam) 27 to a filter 25.

[0025] The gas analyzer 1 includes a controller (control box, control module) 30 that controls each module of the analyzer 1, and an interface device 50 with the outside. The controller 30 includes computer resources such as a CPU and memory, and controls the gas analyzer 1 by loading and executing a program (program product) 39. The program 39 can be provided by being recorded on a computer-readable medium. The interface device 50 includes a power input I / F 52 and an EtherCAT-compliant communication I / F 51.

[0026] The control module (controller) 30 may include a function (ionization control device) 31 for controlling the ionizer 22, a function (filter control device) 32 for controlling the mass filter 25, a function (detector control device) 33 for detecting arriving ions (ion current) via the detector 26, and a function (pressure control device) 34 for controlling the exhaust system 60 to control the pressure of the chamber 29. These control devices 31 to 34 may also have the function of controlling each controlled device (unit) to maintain a set value or condition. The controller 30 may also have a function (cooperative control device) 35 for performing predetermined measurements by cooperatively controlling multiple devices (units) of the gas analyzer 1. For example, the cooperative control device may include a function for setting predetermined conditions in the filter 25 and detecting components selected by those conditions with the detector 26. The ionization control device 31 for controlling the ionizer 22 may also function as an ionization energy control device (filament control device) for controlling the filament current and / or voltage supplied to the filament 23.

[0027] FIG. 2 shows an output assuming that the process gas 109c generated (output) by the gas generation process 101p of the gas generator 101 is directly measured as the sample gas 9 by the analyzer 1. As described above, the sample gas (first gas) 9 to be measured, in this example, the process gas 109c, is an example of the sample gas (first gas) 9 disclosed in Japanese Patent Application Laid-Open Publication No. 2003-060209, which contains, for example, 200 ppm (0.02%) of diborane (B2H6) as a first trace component T1 in hydrogen as a main component (first main component) M1. In a mass spectrometry type gas analyzer, the components in the gas are obtained as intensities relative to the mass-to-charge ratio (m / z) as a result of mass analysis. The sample gas 9 is composed of hydrogen (H2), the main component M1, at a concentration of 99.98% or more, and the concentration (content) of diborane, the trace component T1, relative to the concentration of hydrogen is approximately four orders of magnitude smaller (10 －４ ). For this reason, it is difficult to detect them simultaneously using a detector. Furthermore, when trying to obtain the detection intensity of diborane, which is the trace component T1, the detection intensity of hydrogen, which is the main component M1, becomes enormous, making it difficult to ensure the life of the detector. Therefore, it was thought that it was impossible to measure such a sample gas 9 using a mass spectrometry type gas analyzer.

[0028] 3 shows an example of an output obtained when the mixed gas 19 supplied from the preparation device 10 of this example is measured by the gas analyzer 1. The preparation device (gas mixing device, gas conditioner) 10, for example, mixes a sample gas (first gas) 9 and a standard gas (second gas) 18 in a 1:1 ratio and supplies a portion of the mixed gas 17, for example, 5%, to the analyzer 1 as the gas to be analyzed 19. Therefore, the preparation device 10 includes a first flow controller 11 for supplying a certain amount of the sample gas 9 as the mixing gas 15, a second flow controller 12 for supplying a certain amount of the standard gas 18 as the mixing gas 16, and a third flow controller 13 for supplying a portion of the mixed gas 17 to the gas analyzer 1 as the gas to be analyzed 19. The remaining mixed gas 17 not supplied to the gas analyzer 1 is exhausted from the preparation device 10 and may be sent to a gas treatment facility together with the exhaust gas from the gas analyzer 1.

[0029] An example of the first flow rate controller 11 and the second flow rate controller 12 is a mass flow controller (MFC). For example, the first flow rate controller 11 and the second flow rate controller 12 control the flow rates (inflow rates) of the respective gases 15 and 16 to 1 sccm to generate a mixed gas 17 of 2 sccm. An example of the third flow rate controller 13 is a flow control valve, which supplies a small flow rate (several percent) of the generated mixed gas 17 to the gas analyzer 1 that is acceptable for the gas analyzer 1. For example, 0.1 sccm of the mixed gas 17 is supplied from the preparation device 10 to the gas analyzer 1 as the gas to be analyzed, and the remaining 1.9 sccm of the mixed gas 17 is exhausted. Note that these flow rates are merely examples and are not limited thereto. In this example, the preparation device 10 supplies a portion (a small amount) of the mixed gas 17 to the gas analyzer 1 as the gas to be analyzed 19, allowing the flow rates of the sample gas 9 and the standard gas 18 when mixed to be set independently of the flow rates supplied to the gas analyzer 1. Therefore, the flow rates of the sample gas 9 and the standard gas 18 supplied to the preparation device 10 may be set to amounts sufficient to be controlled with sufficient precision by the flow rate controllers 11 and 12, for example, MFCs.

[0030] In this example, the sample gas (first gas) 9 to be measured is diborane gas, which contains hydrogen as the main component (first main component) M1 and 200 ppm of diborane as the trace component T1. An example of the standard gas (calibration gas, second gas) 18 supplied from the standard gas source 80 is hydrogen gas (argon-added hydrogen gas) containing hydrogen as the main component (second main component) and 10% argon Ar as the second component R1. It is not easy to prepare a standard gas containing a specific component in ppm as a standard sample (internal standard sample), and attempting to measure the components (trace components) contained in such a gas can result in problems similar to those encountered with the first gas in this example.

[0031] However, it is relatively easy to precisely adjust the argon concentration in the standard sample R1 to 10% relative to the major component (second major component), and this standard gas 18 can be obtained at low cost. Argon is an element with atomic number 18, and its stable isotopes are 40Ar (mass-to-charge ratio: 40) at 99.6%, 38Ar (mass-to-charge ratio: 38) at 0.06%, and 36Ar (mass-to-charge ratio: 36) at 0.34%. Therefore, in a standard gas 18 with a 10% argon concentration, the concentration of 36Ar, which has a low abundance, is 340 ppm, which is close to the concentration of diborane, the trace component T1 to be measured (analyzed). Therefore, by using 36Ar as the internal standard sample R1 for the trace component T1, the standard gas 18 containing 10% argon can be used as a calibration gas containing an internal standard sample R1 equivalent to the trace component T1 in ppm units. Therefore, the standard gas 18 containing the internal standard sample corresponding to the trace component can be easily obtained at low cost.

[0032] For example, when preparing mixed gas 19 by mixing sample gas 9 and standard gas 18 in a 1:1 ratio in preparation apparatus 10, the composition of mixed gas 19, if sample gas 9 is generated according to the specifications of process 101p of gas generator 101, will contain 100 ppm diborane (B2H6), 5% argon, the remainder hydrogen, and 170 ppm 36Ar. Therefore, as shown in FIG. 3 , in the measurement results (detection results) of gas analyzer 1, the peaks (intensities) of trace component T1 to be measured in sample gas 9 and internal standard sample R1 in standard gas 18 are nearly identical, allowing for accurate comparison of the intensities of trace component T1 and internal standard sample R1. Therefore, by comparing the intensity of internal standard sample R1, whose concentration is known, with the intensity of trace component T1, the concentration (ratio, content, amount) of trace component T1 contained in sample gas 9 can be accurately determined. Furthermore, in the gas analyzer 1, there is no need to measure the main component M1 of the sample gas 9, and furthermore, there is no need to measure the argon isotope 40Ar, which is present in a high proportion in the standard gas 18, so deterioration of the detector 26 can be suppressed.

[0033] The cooperative control function 35 of the controller 30 of the gas analyzer 1 includes a first control device (first cooperative control device) 36 configured to set the filter 25 so that the detector 26 detects diborane (B2H6, molecular weight 26) as the first trace component T1 contained in the mixed gas 19 to be analyzed, and a second control device (second cooperative control device) 37 configured to set the filter 25 so that the detector 26 detects one of the rare isotopes of argon (Ar) as the second component (standard sample R1) of the standard gas 18, in this example, Ar. Instead of detecting hydrogen as the first major component M1 of the sample gas 9, the second control device 37 also measures the rare isotope of standard sample R1, in place of the rare isotope of standard sample R1, in this example, Ar. That is, the second control device 37 does not detect hydrogen, which is the first main component M1 of the sample gas 9, and does not detect the isotope with a high abundance in the standard sample R1, which is the second component of the standard gas 18, namely, 40Ar in this example, but measures the isotope 36Ar with a low abundance in the standard sample R1, thereby making it possible to determine the concentration of diborane, which is the trace component T1 to be measured, with high accuracy.

[0034] The second control device 37 may measure 38Ar having an abundance ratio of 0.06% at a mass-to-charge ratio of 38 in addition to 36Ar as the isotope with a low abundance ratio in the standard sample R1. Since the abundance ratio of these isotopes is 0.40%, it is easy to deal with cases where the concentration of the trace component T1 to be measured in the sample gas 9 is higher than in this example. Furthermore, the second control device 37 may measure only 38Ar having an abundance ratio of 0.06% instead of 36Ar having an abundance ratio of 0.34% as the isotope with a low abundance ratio in the standard sample R1. In the gas analyzer 1 of this example, an intensity equivalent to 30 ppm can be obtained for the standard sample R1, making it easy to deal with cases where the concentration of the trace component T1 to be measured in the sample gas 9 is even lower than in this example.

[0035] The gas analyzer 1 may continuously determine the concentration of trace component T1 in the sample gas 9 in real time by comparing the detection intensity of the standard sample R1 with the detection intensity of the trace component T1 using an internal standard method with a standard gas (reference gas, calibration gas) 18. The gas analyzer 1 may also be calibrated in advance using an external standard method with the standard gas 18. The gas analyzer 1 of this example can measure, for example, 36Ar in the standard gas 18 under the same measurement conditions in advance to determine the relationship between the detection intensity and the concentration of 36Ar. The controller 30 of the gas analyzer 1 may include an output device (computing function, computing device) 38 that stores the calibration results 38a and, when measuring the mixed gas 19 on-site, determines the concentration (mixing ratio) of trace component T1 from the ratio of the detection intensity of 36Ar to the detection intensity of other components.

[0036] The analysis results of the gas analyzer 1 can be provided to the process controller 105 via a communication interface 51, such as an EtherCat, of the interface device 50. The analysis results may also be provided to another external device monitoring the process 101p via the cloud. The process controller 105 may include computer resources such as a CPU and memory, and may be operated by a control program (program product) 108. The process 101p controlled and / or monitored by the process controller 105 is not limited to this example, and may be a processing device 101 into which process gases used in semiconductor processing flow or are discharged. At least one of input, intermediate, and output process gases 109a to 109c of the processing device 101 can be supplied from the supply device 102 via the preparation device 10 to the gas analyzer 1 and analyzed, and the processing device 101 and the process 109p can be controlled and monitored based on the analysis results.

[0037] 4 shows an example of a control process (control method, control program) in a process monitoring system 100 including a gas analyzer 1. In the following example, a diborane gas 109b containing 200 ppm of diborane as a trace component T1 relative to hydrogen as a main component (first main component) M1 is generated in a gas generator 101, and the composition of the diborane gas 109b is verified in the gas analyzer 1 using argon-added hydrogen gas containing 10% argon Ar as a standard gas 18, in which hydrogen is the main component (second main component) M2, and a standard sample R1 is used, and a generation process 101p of the gas generator 101 is managed based on the verification results.

[0038] First, in step 81, at least one of the process gases 109a-109c at the input, intermediate, or output of the processing device 101, into which the process gas flows or is discharged, is selected as the gas to be measured by the supply device 102, and supplied to the preparation device 10 as the sample gas 9. In step 82, the gas analyzer 1 starts gas analysis. First, the gas analyzer 1 sets the ionization energy of the ionizer 22 to a value appropriate for the gas 9 to be measured by the ionization control device 31. The ionization energy of the ionizer 22 is often set to 70 eV because mass spectra registered in existing databases such as NIST are measured at 70 eV, but the ionization energy may also be selected appropriately by the ionization control device 31. The gas analyzer 1 sets the pressure of the chamber 29 by the pressure control device 34.

[0039] Next, in step 83, the preparation device 10 prepares the mixed gas 19 to be analyzed. That is, the preparation device 10 mixes a first gas (sample gas) 9 containing a first trace component T1 to be measured in a first main component M1 with a second gas (standard gas) 18 containing a second component (standard sample) R1 at a predetermined ratio in a second main component M2, and supplies a portion of the mixed gas 19 to the analyzer 1 as the gas to be analyzed. In step 83, the inflow rate of the sample gas (first gas) 9 is controlled by the first flow controller (MFC) 11, the inflow rate of the standard gas (second gas) 18 is controlled by the second flow controller (MFC) 12, and further, the amount of the mixed gas 17 of the sample gas 9 and the standard gas 18, the inflow rates of which are controlled at 1:1 by the MFCs 11 and 12, supplied to the analyzer as the gas to be analyzed by the third flow controller 13 may be controlled.

[0040] In step 84, the controller 30 of the analytical device 1 does not detect hydrogen, which is the main component (first main component) M1 of the sample gas 9 and the main component (second main component) M2 of the standard gas 18, for the mixed gas 19 in step 85, but instead controls the analytical device 1 to detect a standard sample R1 of the standard gas 18, as will be described below. That is, the second control device 37 of the controller 30 controls the filter 25 so that hydrogen (H2), which is the main component M1 and M2, is not selected, or controls the detector 26 so that it does not detect an ion current when hydrogen is selected by the filter 25.

[0041] In step 86, for diborane, which is the first trace component T1 to be measured, the first control device 36 controls the process in step 87 so that diborane contained in the mixed gas 19 to be analyzed, supplied from the preparation device 10, is selected by the filter 25 and detected by the detector 26.

[0042] In step 88, for argon, which is the standard sample R1 of the standard gas 18, the second control device 37 selects 36Ar, a low-abundance isotope of argon contained in the mixed gas 19 to be analyzed, using the filter 25 and detects it with the detector 26 in step 89 instead of 40Ar, a high-abundance isotope of argon contained in the mixed gas 19 to be analyzed (without detecting 40Ar). For example, the second control device 37 sets the filter 25 so that only 36Ar is selected, and measures (detects) the ion flow that has passed through the filter 25 with the detector 26 at that timing. The second control device 37 may set the filter 25 so that 40Ar does not pass through (i.e., does not set a timing for passing), or may turn off the detector 26 when 40Ar passes through the filter 25 (so that the ion flow is not detected).

[0043] In step 90, the gas analyzer 1 may output, via the output device 38, the concentrations of trace components obtained by comparing the detection intensity of trace component T1 with the detection intensity of standard sample R1, or the concentrations (mixing ratios) obtained based on the calibration results 38a, to the process controller 105. Furthermore, information on impurities at ppm or sub-ppm levels, such as helium (He), methane (CH), nitrogen (N), oxygen (O), carbon dioxide (CO), and carbon tetrafluoride (CF), obtained during the gas analysis process, may be output to the process controller 105. In step 91, the process controller 105, as a process management device, manages the gas generator 101 or the gas generation process 101p performed by the gas generator based on the measurement results (analysis results) of the gas analyzer 1.

[0044] In gas analysis, there is a demand for quantifying the concentration of mixed gases in real time and avoiding the need to shut down the instrument every time a calibration curve is created. Furthermore, it can be difficult to calculate the impurity concentration based on the ratio of base peak to impurity, and detecting the base peak due to excessive concentration differences can lead to detector degradation. In addition, there are cases where isotopes or multivalent ions of the base component do not exist or cannot be used. In such situations, the system 100 of this example enables measurement using the internal standard method by using the preparation device 10 to simultaneously flow a low-cost gas (standard gas, reference gas, calibration gas) 18, which is based on the same components as the base component and contains a certain amount of impurities, with the gas 9 to be measured. Mass flow controllers 11 and 12 can be used to accurately control the flow rates of the sample gas 9 and the standard gas 18. Even when it is difficult to control the trace amount of gas input to the gas analyzer 1, accurate measurement of trace components can be achieved by supplying only a portion of the mixed gas 17, prepared to a certain amount, to the gas analyzer 1 as the gas 19 to be analyzed.

[0045] An example of the analysis results of the analyzer 1 of this embodiment is shown in FIG. 3 . The first control device 36 measures diborane as the trace component T1 to be measured, and the second control device 37 measures 36Ar contained in the same mixed gas 19 before and after the diborane measurement under the same conditions except for the setting of the filter 25. By detecting 36Ar, a low abundance isotope, the concentrations of diborane and 36Ar contained in the mixed gas 19 become approximately equal or at the same level, and the detection intensities become approximately equal. Therefore, the gas analyzer 1 can measure diborane and 36Ar with high accuracy. Furthermore, the first control device 36 and the second control device 37 enable the gas analyzer 1 to measure (detect) only diborane and 36Ar from among the components (composition) contained in the mixed gas 19, without needing to detect the main component hydrogen or other isotopes of argon that are highly abundant. Therefore, it is not necessary to measure components with large concentration differences, and it is possible to prevent the detection intensity in the detector 26 from becoming too high, and to prevent deterioration of the detector 26.

[0046] Furthermore, in the gas analyzer 1, the output function 38 may accurately identify the concentration of diborane contained in the mixed gas 19 in real time from the detection intensities of diborane and 36Ar based on the results of a prior calibration using 36Ar. Therefore, the gas analyzer 1 can accurately determine the concentration of diborane, which is a trace component contained in the diborane gas 109b generated in the gas generator 101, on-site. Furthermore, the measurement results (analysis results) of the gas analyzer 1 can be used to control, manage, and monitor the process 101p.

[0047] In the above, a gas containing hydrogen as the second major component and argon as the internal standard is referred to as an example of a standard gas (second gas). However, the standard gas (reference gas) is not limited to this and may contain other isotopes in appropriate abundance ratios and may contain components that can be measured separately from the components to be measured. The gas to be analyzed (measured) is not limited to a semiconductor material gas containing a carrier gas (first major component) such as hydrogen and trace components (first components) such as monosilane, arsine, phosphine, and diborane. It may also be a gas used for other purposes and containing trace components of 1 to several hundred ppm. Furthermore, while an example of a quadrupole-type mass filter is described as the filter 25, the filter 25 may be of other types, such as a TOF, ion trap, or Wien filter, as long as it can select, sort, and turn on / off components containing molecules and / or atoms based on their mass-to-charge ratio (m / z).

[0048] Furthermore, while particular embodiments of the present invention have been described above, various other embodiments and modifications may be devised by those skilled in the art without departing from the scope and spirit of the present invention, and such other embodiments and modifications are within the scope of the following claims, which define the present invention.

Claims

1. An analytical device for analyzing the components contained in gas, A system comprising a preparation device that supplies a portion of a mixed gas to the analytical device, which is obtained by mixing a first gas containing a first trace component of the object to be measured contained in a first main component and a second gas containing a second component in a predetermined ratio in a second main component, in a predetermined proportion, The analytical apparatus includes a filter that selectively passes through components contained in the mixed gas, The system includes a detector for detecting components that have passed through the filter, The system includes a first control device configured to set the filter so that the detector detects the first trace component contained in the mixed gas, A system comprising: a second control device configured to set the filter so that, instead of detecting the first principal component, the detector detects at least one of the isotopes of the second component that have a low abundance, instead of an isotope that has a high abundance of the second component.

2. In claim 1, The second control device is configured to set the filter such that only any of the isotopes of the second component having a low abundance is detected by the detector.

3. In claim 1 or 2, The preparation apparatus is configured to supply the mixed gas as the second gas, which includes a standard gas in which the second main component is contained as an internal standard sample.

4. In any of claims 1 to 3, The preparation device includes a first flow controller for controlling the inflow rate of the first gas, A second flow controller for controlling the inflow rate of the second gas, A system including a third flow controller that supplies a portion of the mixed gas to the analyzer.

5. In any of claims 1 to 4, The analytical apparatus is a system that includes an ionizer for ionizing components contained in the mixed gas upstream of the filter.

6. In any of claims 1 to 5, The filter system includes a quadrupole filter.

7. In any of claims 1 to 6, A processing apparatus into which process gas is introduced or discharged, A supply device that supplies at least one of the input, intermediate, or output process gases of the processing apparatus as the first gas to the preparation device, A system comprising a control device that manages the processing device or the process being executed by the processing device based on the analysis results of the analytical device.

8. A control method for a system having an analytical device for analyzing components contained in a gas, The analytical apparatus includes a filter that selectively allows components contained in the gas to be measured to pass through, and a detector that detects the components that have passed through the filter. This method is The preparation device supplies a portion of the mixed gas, obtained by mixing a first gas containing a first trace component of the object to be measured in a first main component and a second gas containing a second component in a second main component in a predetermined ratio, to the analytical device. The controller selects the first trace component contained in the mixed gas using the filter and detects it with the detector, A method comprising, instead of detecting the first principal component, selecting at least one of the isotopes with a low abundance of the second component using the filter and detecting it with the detector, instead of an isotope with a high abundance of the second component.

9. In claim 8, A method comprising selecting at least one of the isotopes of the second component having a low abundance using the filter and detecting it with the detector, wherein the method includes selecting only one of the isotopes of the second component having a low abundance using the filter and detecting it with the detector.

10. In claim 8 or 9, The above supply involves controlling the inflow rate of the first gas with the first flow controller, The amount of gas flowing in the second gas is controlled by the second flow controller, A method comprising controlling the amount of the mixed gas supplied to the analyzer by a third flow controller.

11. In any of claims 8 to 10, The method of supplying includes supplying the mixed gas as the second gas, which includes a standard gas in which the second main component is contained as an internal standard sample.

12. In any of claims 8 to 11, The system includes a processing apparatus into which process gas is introduced or discharged, The apparatus comprises a supply device that supplies at least one of the input, intermediate, or output process gases to the preparation device, A method comprising a system management device that manages the processing device or the process performed by the processing device based on the analysis results of the analysis device.

13. An analytical device for analyzing the components contained in gas, A control program for a system having a preparation device that supplies a portion of a mixed gas to the analyzer, which is obtained by mixing a first gas containing a first trace component of the object to be measured in a first main component and a second gas containing a second component in a second main component in a predetermined ratio, in a predetermined proportion, The analytical apparatus includes a filter that selectively passes through components contained in the mixed gas, The system includes a detector for detecting components that have passed through the filter, The control program involves the controller selecting the first trace component contained in the mixed gas using the filter and detecting it with the detector, A control program including an instruction to select at least one of the isotopes of the second component that has a low abundance, using the filter, and to detect it using the detector, instead of detecting the first principal component.

14. In any of claims 1 to 6, A system further comprising an output device that determines the concentration of the first trace component in the first gas from the intensity detected by the detector of at least one of the isotopes of the second component that are present in a predetermined ratio in the second gas mixed with the first gas in a predetermined ratio, without detecting the first main component, and the intensity detected by the detector of the first trace component.

15. In any of claims 8 to 11, A method further comprising determining the concentration of the first trace component in the first gas from the intensity detected by the detector of at least one of the isotopes of the second component that are present in a predetermined ratio in the second gas mixed with the first gas in a predetermined ratio, without detecting the first main component, and the intensity detected by the detector of the first trace component.