Gas analyzer apparatus and control method

Abstract

To provide a gas analyzer apparatus capable of performing more stable or more highly accurate detection, the analyzer apparatus that detects components contained in a sample gas.SOLUTION: A gas analyzer apparatus 1 includes: a sample chamber 12 that is provided with a dielectric wall structure and into which a sample gas 9 to be measured flows; a plasma generation mechanism 13 for generating plasma 19 inside the sample chamber, which has been depressurized; a gas input apparatus 5 configured to cause only the sample gas to flow from a process 102 into the sample chamber; a first detector 20 configured to detect components in the plasma by filtering ionized gas from the generated plasma; and a second detector 80 configured to analyze light emission of ions in the plasma inside the sample chamber and capable of outputting a second detection result 52 that is to be synchronized with a first detection result 51 of the first detector.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 describes a glow discharge optical emission spectrometry (GD-OES) in which a sample holder includes an electrode (second electrode) having a sample fixing surface, and an outer cylinder and an inner cylinder (contact portion) with the sample fixing surface disposed on the inside. With the sample separated from the opening of the glow discharge tube, the open end of the inner cylinder is contacted with the periphery of the opening. The inside of the glow discharge tube and the outer and inner cylinders, which are connected to each other, is depressurized, and argon gas is supplied. Next, the inner cylinder is moved relative to the outer cylinder to bring the sample closer to the tip of the cylindrical portion (end portion) of the anode (first electrode) of the glow discharge tube, a refrigerant is caused to flow in a flow path (cooling portion) to cool the sample, and a voltage is applied to the electrodes to perform glow discharge optical emission analysis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-27327 A Summary of the Invention [Problem to be solved by the invention]

[0004] 2. Description of the Related Art In an analyzer that ionizes a sample gas and detects components contained in the sample gas, there is a demand for a gas analyzer that is capable of more stable or more accurate detection. [Means for solving the problem]

[0005] One aspect of the present invention is a gas analyzer having a sample chamber having a dielectric wall structure and into which a sample gas to be measured flows, a plasma generation mechanism for generating plasma in the sample chamber at a reduced pressure by an electric field and / or a magnetic field via the dielectric wall structure, a gas input device configured to allow only sample gas from a process to flow into the sample chamber, a first detector for filtering ionized gas in the generated plasma to detect components in the plasma, and a second detector for analyzing the light emission of ions in the plasma in the sample chamber and outputting a second detection result synchronized with the first detection result of the first detector. In this gas analyzer, the plasma that is the ion source of the first detector can be subjected to light emission analysis by the second detector. Therefore, a common ionized sample can be analyzed by different methods synchronously, i.e., simultaneously in parallel, or with a limited time interval (latency) or time difference that is specific to this gas analyzer and can be set in advance, and analytical data can be generated that correlates the detection results by the different methods.

[0006] Typically, the first detection result includes a mass spectrum acquired by time division (time lapse), that is, serially (sequentially) because it is necessary to change the conditions for detection by the filter. On the other hand, the second detection result includes an emission spectrum that can be acquired in parallel by spectroscopy. This gas analyzer includes a sample chamber that generates a common plasma that serves as an ion source and an emission source separately from the process, and includes first and second detectors whose routes are fixed in advance to the sample chamber. Therefore, the serial first detection result and the parallel second detection result for the common plasma generated in the sample chamber can be acquired synchronously, and they can be generated and output as analytical data by relating them. For this reason, for example, by checking the fluctuation of the parallel second detection result during the time interval during which the serially acquired first detection result is obtained, it is possible to verify that the first detection result is information from the same conditions, for example, a process under the same conditions or plasma maintained under the same conditions, and more reliable analytical results can be obtained.

[0007] In addition, by generating a microplasma in the sample chamber of the gas analyzer, the volume of the common ion source and light emission source to be detected can be reduced, and the first and second detection results can be obtained for the same target. Furthermore, it is possible to limit the serially obtained mass spectrum to a region of interest (ROI), and by confirming wide-range information with the second detection result obtained in parallel, and serially acquiring the ROI with the first detection result, it is possible to obtain more accurate analysis results for the ROI at short time intervals, including temporal fluctuations, while confirming wide-range information.

[0008] The gas analyzer may have a first analyzer for analyzing the sample gas based on a first detection result and a second detection result synchronized with the first detection result at a time interval defined by the gas analyzer. By utilizing the difference in spectral interference between the first detection result and the second detection result, more accurate analysis is possible by cooperating the detection results.

[0009] Another aspect of the present invention is a method for controlling a system having a gas analyzer, comprising synchronously outputting a first detection result from a first detector and a second detection result from a second detector. The synchronous outputting may include outputting the first detection result including a mass spectrum acquired in a time-division (serial) manner in association with a second detection result including an emission spectrum synchronously comparable to the first detection result (parallel). The mass spectrum may include a mass spectrum limited to a region of interest (ROI).

[0010] Yet another aspect of the present invention is a program (program product) for controlling a system having a gas analyzer by a computer according to the method for controlling the system. The program includes instructions for executing the control of the system. The program may be provided in a form recorded on a suitable computer-readable medium. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a process monitoring system including a gas analyzer. [Diagram 2] FIG. 13 is a diagram showing an example of analysis data. [Diagram 3] 4 is a flowchart outlining the operation of a process monitor. [Figure 4] FIG. 1 illustrates another example of a process monitoring system including a gas analyzer. [Diagram 5] FIG. 13 illustrates yet another example of a process monitoring system including a gas analyzer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 1 shows a schematic configuration of a process monitoring system 100 as an example of a system including a gas analyzer 1. The gas analyzer 1 analyzes a sample gas 9 supplied from a process chamber 101 in which a plasma process 102 is performed. The plasma process 102 performed in the process chamber 101 is typically a process for forming various types of films or layers on a substrate or a process for etching the substrate, and includes CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition). The plasma process 102 is not limited to a process related to semiconductor manufacturing, and may be a process for stacking various types of thin films on a substrate made of an optical component such as a lens or a filter.

[0013] For example, in recent years, semiconductor chip structures have become three-dimensional due to demands for increased memory capacity, improved logic speed, and lower power consumption. As a result, in semiconductor process control, processes have become more complex, atomic-level quality is required, and the cost of measurement and monitoring is increasing. Monitoring gases including reactants and by-products is important for process matching, transition point measurement during film formation, and detection of etching end points, and it is said that it is difficult to monitor processes comprehensively with the plasma optical emission measurement (OES) currently adopted as standard. On the other hand, residual gas analyzers and mass spectrometers with ion sources that use conventional hot filaments have a problem with their lifespan due to damage caused by semiconductor gases.

[0014] In the process monitoring system 100 using the gas analyzer 1 of this embodiment, real-time monitoring is performed even in harsh environments, and highly reliable measurement results are provided, thereby providing innovative process control. The gas analyzer 1 functions as a total solution platform developed for the purpose of dramatically improving the throughput in semiconductor chip manufacturing and maximizing the yield rate. As described above, the gas analyzer 1 of this embodiment has a very small installation area, so it can be directly connected to the chamber 101. In addition, standard protocols currently mainly adopted in semiconductor manufacturing process equipment, such as the Either Cat protocol, can be installed in the PLC 50 and integrated into the process equipment control system 100.

[0015] The gas analyzer 1 includes an ionizer 10 that generates ions (ion flow) 17 of a sample gas 9, and a sensor group (sensor group, sensor suite, analysis group) 90 that detects ions supplied from the ionizer 10 or generated in the ionizer 10. The ionizer 10 includes a plasma generation unit (plasma generation device) 11 that generates plasma 19 of the sample gas 9 to be measured that is supplied from a process 102 via a sample input 3a. The plasma generation unit 11 includes a chamber (sample chamber) 12 having a dielectric wall structure 12a and into which the sample gas 9 to be measured flows, a high-frequency supply mechanism (RF supply mechanism, plasma generation mechanism) 13 that generates plasma 19 in the sample chamber 12, which has been decompressed, by a high-frequency electric field and / or magnetic field via the dielectric wall structure 12a, and a plasma controller 16 that controls the frequency and power of the high frequency. The plasma 19 is supplied as an ion flow 17 from an opening 18 provided at one end of the sample chamber 12 to a first detector 20, which will be described later. The gas analyzer 1 includes a gas input device 5 configured to allow entry into a sample chamber 12 of only a sample gas 9 from a process chamber 101 in which a plasma process 102 is carried out.

[0016] The gas analysis sensor group 90 includes a first detector 20 that filters the ionized gas in the plasma 19 supplied as ions (ion flow) 17 to detect components in the plasma, and a second detector 80 that analyzes (spectroscopically analyzes) the light emission of the ions in the plasma 19 in the sample chamber 12. An example of the first detector (first sensor, first detector, first measuring device) 20 is a mass spectrometry type detector (mass spectrometer, MS). The first detector 20 includes a filter unit (mass filter, quadrupole filter in this example) 25 that filters the ionized sample gas (sample gas ions) 17 according to the mass-to-charge ratio, and a detector 26 that detects the filtered ions. The gas analysis device 1 further includes a vacuum container (housing) 40 that houses the filter unit 25 and the detector 26, and an exhaust system 60 that maintains the inside of the housing 40 under an appropriate negative pressure condition (vacuum condition).

[0017] The exhaust system 60 of this example includes a turbomolecular pump (TMP) 61 and a Roots pump 62. The exhaust system 60 is of a split flow type that also controls the internal pressure of the sample chamber 12 of the plasma generating device 11. Of the multi-stage TMP 61 of the exhaust system 60, a stage that provides a negative pressure suitable for the internal pressure of the chamber 12 or the input of the Roots pump 62 is connected to the chamber 12, so that the internal pressure of the chamber 12 is controlled.

[0018] Therefore, the gas analyzer 1 of this embodiment has an exhaust device 60 that exhausts gas from the sample chamber 12, and the exhaust device 60 includes a first exhaust path 65 that exhausts gas from the sample chamber 12 while bypassing the first detector 20, and a second exhaust path 66 that exhausts gas via the first detector 20. By providing the first exhaust path 65 that exhausts gas from the sample chamber 12 while bypassing the first detector 20, it becomes possible to introduce the sample gas 9 into the sample chamber 12 and control the internal pressure of the sample chamber 12, separately from the gas flow rate that is passed through the first detector 20 for filtering. Therefore, the amount of gas flowing through the first detector 20 can be stabilized, and the detection accuracy can be stabilized. On the other hand, since a sufficient amount of sample gas 9 can be drawn into the sample chamber 12 from the process via the gas input device 5, a gas analyzer 1 that can monitor the state (fluctuation) in the process chamber 101 in real time can be provided.

[0019] The mass filter 25 in this example includes four cylindrical or columnar electrodes 25a with an inner surface finished in a hyperbolic shape to form a hyperbolic electric field for filtering by mass-to-charge ratio. The quadrupole type mass filter 25 may be a quadrupole type having a large number of cylindrical electrodes, for example, nine, arranged to form a matrix (array) to form multiple pseudo-hyperbolic electric fields. The detector 26 includes a Faraday cap and a secondary electron multiplier, which may be used in combination or by switching between them. The detector 26 may be of other types, such as a channel type secondary electron multiplier, a microchannel plate, etc.

[0020] The plasma generating device 11 of this example includes a sample chamber 12 for plasma generation that is integrally built into the inside of the housing 40. The outer shell of the chamber 12 is made of Hastelloy, and an insulated cylindrical electrode is inserted inside, and plasma 19 is generated inside the chamber 12. Only the sample gas 9 flows from the process chamber 101, where the process 102 to be monitored is performed, through the gas input device 5 and the sample input 3a into the depressurized sample chamber 12, and plasma 19 is generated inside the sample chamber 12. That is, in the plasma generating device 11, an assist gas (support gas) such as argon gas is not used, and only the sample gas 9 generates the plasma 19 for analysis. The wall 12a of the sample chamber 12 is made of a dielectric material, and examples of such materials include quartz, aluminum oxide (Al2O3), silicon nitride (SiN3), and other light-transmitting dielectric materials that are highly durable against plasma.

[0021] In the plasma generating device 11, the mechanism for generating plasma (RF supply mechanism) 13 generates plasma 19 by an electric field and / or a magnetic field through a dielectric wall structure 12a inside the sample chamber 12 without using a plasma torch. One example of the RF supply mechanism 13 is a mechanism for exciting the plasma 19 with radio frequency (RF) power. Examples of the RF supply mechanism 13 include inductively coupled plasma (ICP), dielectric barrier discharge (DBD), and electron cyclotron resonance (ECR). The plasma generating mechanism 13 of these types may include a radio frequency power source and an RF field forming unit. A typical example of the RF field forming unit includes a coil arranged along the sample chamber 12. The plasma generating device 11 of this example includes a function for igniting by changing the matching state by changing the frequency of the RF field. For example, after igniting the plasma by inputting a pulsed radio frequency power, the plasma can be generated and maintained by transitioning to a steady operating state. The plasma generating device 11 may be a type that forms an inductively coupled plasma (ICP) using an assist gas such as argon gas and then introduces a sample gas to ionize it, but it is preferable to form plasma 19 using only the sample gas, and the assist gas may be made unnecessary by generating a microplasma.

[0022] The internal pressure of the sample chamber 12 in this example may be a pressure at which plasma is easily generated, for example, in the range of 0.01-1 kPa. When the internal pressure of the process chamber 101 is controlled to about 1-several hundreds of Pa, the internal pressure of the sample chamber 12 may be controlled to a lower pressure, for example, about 0.1-several tens of Pa, and may be controlled to 0.1 Pa or more, or 0.5 Pa or more, 10 Pa or less, or 5 Pa or less. For example, the inside of the sample chamber 12 may be depressurized to about 1-10 mTorr (0.13-1.3 Pa). By maintaining the sample chamber 12 at the above-mentioned reduced pressure, it is possible to generate plasma 19 at a low temperature using only the sample gas 9. The sample chamber 12 may be a small chamber capable of generating plasma 19, for example, a chamber with a total length of 1-100 mm and a diameter of 1-100 mm, or a chamber (miniature chamber) with a size of several mm to several tens of mm. It is possible to provide a gas analyzer 1 with excellent real-time performance by reducing the volume of the sample chamber 12. The sample chamber 12 may be cylindrical.

[0023] The gas analyzer 1 further includes, as the ionizer 10, an electron ionizer (filament, EI ion source) 15 that ionizes (electron ionizes) the sample gas 9 to be measured, which is supplied from the process 102 through the gas input device 5 and the sample input 3b, by electron impact. The EI ion source 15 operates at a high vacuum, and can be used for the purpose of sensitivity correction even when the process in the process chamber 101 to be monitored is in a high vacuum and difficult to generate microplasma 19. The gas supply device 5 includes a connection pipe 5c connected to the process chamber 101, a valve 5a that controls the flow of the sample gas 9 between the connection pipe 5c and the sample input 3a for plasma ionization, and a valve 5b that controls the flow of the sample gas 9 between the connection pipe 5c and the sample input 3b for EI ionization. The detection mode (measurement mode) of the gas analyzer 1 can be automatically or manually switched by switching the valves 5a and 5b using the process controller 105. The EI ion source 15 is provided between the sample input 3b and the filter unit 25, and faces a flow path common to the flow path of the ion flow 17 from the plasma (microplasma) 19 formed in the sample chamber 12. Therefore, the EI ion source 15 can electronically ionize the sample gas 9 from the gas input device 5, and can also ionize the gas (derived gas of the plasma 19) from the sample chamber 12 and supply it to the first detector 20.

[0024] In one embodiment, when the process controller 105 executes a highly reactive process 102 under a high internal pressure of the process chamber 101, for example, 1 Pa or more, the valve 5a is opened to supply the sample gas 9 to the gas analyzer 1. The control device 50 of the gas analyzer 1 generates a plasma (microplasma) 19 of the sample gas 9, which is different from the process 102, using the sample gas 9, and extracts ions 17 from the microplasma 19 to perform mass analysis. At this time, the EI ion source (filament) 15 is not lit, and the valve (port) 5b is closed. When the internal pressure of the process chamber 101 is low, for example, when measuring the ultimate pressure, the port (valve) 15a on the plasma side may be closed, the port 5b on the EI side may be opened to supply the sample gas 9, and the internal state of the process chamber 101 may be monitored by lighting the filament (activating the EI).

[0025] The gas analyzer 1 may include an energy filter 28 disposed between the EI ionization source 15 and the filter 25. The energy filter 28 may be a Bessel-Box, a CMA (Cylindrical Mirror Analyzer), or a CHA (Concentric Hemispherical Analyzer). The Bessel-Box type energy filter 28 is composed of a cylindrical electrode, a disk-shaped electrode (having the same potential as the cylindrical electrode) disposed at the center of the cylindrical electrode, and electrodes disposed at both ends of the cylindrical electrode, and operates as a band-pass filter that passes only ions having a specific kinetic energy by the electric field created by the potential difference Vba between the cylindrical electrode and the electrodes at both ends and the potential Vbe of the cylindrical electrode. In addition, the disk-shaped electrode disposed at the center of the cylindrical electrode can prevent soft X-rays generated during plasma generation and light generated during gas ionization from directly entering the ion detector 26, thereby reducing noise. In addition, the energy filter 28 can eliminate ions and neutral particles that are generated in the ion generation section or externally and enter the filter unit 25 parallel to the central axis, resulting in a structure that can suppress detection of such particles.

[0026] An example of the second detector (detector, analyzer, sensor) 80 is an optical emission spectrometry detector, typically an optical emission spectrometry device (Optical Emission Spectrometer, OES, Atomic Emission Spectrometry, AES). An example of the OES 80 includes a light receiving or condensing element 81 such as an objective lens attached to the light-transmitting dielectric wall structure 12a of the sample chamber 12 in parallel with the RF supply mechanism 13 or coaxially with the coil of the RF supply mechanism 13, an optical fiber 82 that guides light from the condensing element 81, and a spectroscopic analysis unit (OES unit, OES detection device) 85 that performs spectroscopic analysis of the light supplied by the optical fiber 82. The spectroscopic analysis unit 85 may be any type of detection device employed in the OES 80, such as a sequential type or a multi-channel type.

[0027] The gas analyzer 1 includes a control module 30 that controls each module of the analysis unit 20 under the PCL 50. The control module 30 includes a control module 35 that controls the mass analyzer 20, a unit 31 that controls the extraction of the plasma 19, a unit 32 that controls the electron ionizer 15, a filter control function (filter control device) 33 that controls the RF and DC voltages of the mass filter 25 to select a region (region of interest, ROI) of the object (ions) to be measured by the filter 25, and a function (intensity detection device) 34 that controls the detector 26 to obtain a detection current. The control module 35 may include a function to control the potential of the lens group of the mass analyzer 20, a function to control the potential of the energy filter 28, and the like. The control unit 32 of the EI unit 15 may include a filament control function that controls the filament current and voltage.

[0028] The PLC (controller) 50 that controls the gas analyzer 1 includes computer resources such as a CPU 56 and a memory 55, and controls the gas analyzer 1 by loading and executing a program (program product) 59. The program 59 includes instructions for implementing and operating each function described below in the PLC 50. The PLC 50 includes a function as a generator 57b that associates a first detection result 51 of the first detector 20 and a second detection result 52 of the second detector 80 to generate synchronized analysis data 53. The program 59 can be provided by being recorded on a computer-readable medium.

[0029] FIG. 2 shows a schematic diagram of a first detection result 51 and a second detection result 52. An example of the first detector 20 is a mass spectrometer (MS) that measures the mass and intensity of elements ionized in the plasma. An example of the first detection result 51 is the intensity relative to the mass-to-charge ratio (m / z). An example of the second detector 80 is an optical emission spectrometer (OES) that measures the wavelength and intensity of light emitted from elements excited in the plasma. An example of the second detection result 52 is the intensity relative to the wavelength. Features (advantages) of the first detector (MS) 20 over the second detector (OES) 80 include high sensitivity, a wide dynamic lens, quantitative measurement of multiple elements, isotope ratio measurement, and simple spectrum. Disadvantages include a decrease in separation ability due to mass spectrum interference.

[0030] That is, the MS20 is superior in terms of sensitivity, and while the OES80 is on the sub-ppb level, the MS20 is capable of detecting sub-ppt. On the other hand, in terms of measurement time, since the output of the OES80 is an emission spectrum, the second detection result 52 can basically be obtained at the sensitivity of the spectrometer, and there is no change in the measurement time (detection time) even if the number of elements (components) contained in the sample gas 9 increases. Also, the second detection result 52 contains information on all elements (components) within the range in which a spectrum can be obtained. In the MS20, since the conditions of the filter 25 are changed in a time-division manner for measurement, the measurement time depends on the number of elements and mass numbers to be measured, and the first detection result 51 contains only data on the (measured mass number) that was the measurement target. In terms of spectral interference, the MS20 cannot separate elements (components) with the same mass-to-charge ratio m / z, and it is difficult for the OES80 to separate elements (components) with spectra of the same or close frequencies.

[0031] Therefore, when focusing on the measurement time, as shown in FIG. 2, the first detection result 51 includes mass spectra acquired by time division (time lapse), that is, serially (sequentially). That is, when spectrum acquisition is started at time t1 (51a), as shown at time t2, mass-to-charge ratios m / z are searched in order (51b), and a detection result (mass spectrum 51c) having a spectrum of a desired mass-to-charge m / z (region of interest, ROI) 51r can be obtained at time tn. Even with a relatively high-speed MS, it takes about 1 ms to measure with a filter condition set for one m / z, and it is possible to measure 1000 points (m / z) in one second, but the measurement time increases significantly compared to OES80. Furthermore, if one tries to improve the detection sensitivity (quantitative measurement sensitivity), time is consumed because the measurement time at one point increases. On the other hand, if time is consumed, high-precision measurement is possible, and a highly sensitive measurement result (detection result) 51 can be obtained by measuring components limited to a desired ROI.

[0032] On the other hand, the second detection result 52 includes an emission spectrum that can be obtained instantly (on the order of ms or less) in parallel with at least the first detection result 51 by spectroscopy. Therefore, the second detection results 52a, 52b, and 52c obtained at times t1, t2, and tn are the same unless the state of the microplasma 19 changes. Therefore, the reliability of the first detection result 51 obtained serially can be ensured by synchronizing and associating the second detection result 52 and the first detection result 51 obtained in parallel. The synchronization between the first detection result 51 and the second detection result 52 is mainly related to two latencies inherent to this gas analyzer 1.

[0033] One of the reasons for the time difference is that the first detection result 51 is the result of filtering the ion flow 17 supplied from the microplasma 19 by the filter 25, and the ions need to physically reach the detector 26. In other words, if there is a fluctuation in the microplasma 19, in order to detect the fluctuation, it takes time for the ions to physically reach the detector 26 of the first detector 20, and there is a time difference (latency) from the state of the plasma 19.

[0034] In contrast, the second detection result 52 is an emission spectrum, and if there is a change in the state of the microplasma 19, it appears in the detection result without any time difference. However, in the gas analyzer 1, the microplasma 19 generated in the fixed sample chamber 12 is the subject of inspection by the first detector 20 and the second detector 80, and the time difference between the first detection result 51 and the second detection result 52 can be set in advance as a value specific to the gas analyzer 1. Therefore, the time difference between the first detection result 51 and the second detection result 52 is known in the generation device 57b, and the first detection result 51 and the second detection result 52 can be generated as analysis data 53 in a synchronized state. This makes it possible to accurately obtain detection results of the microplasma 19 by different methods at the same time.

[0035] Another factor is that, as described above, the first detector 20 requires a certain time to obtain the first detection result (the scanned first detection result, the mass spectrum) 51c including the desired ROI. For example, if there is a change in the state of the microplasma 19 while scanning the mass spectrum, the mass spectrum 51c obtained at the time tn may not reflect the state of the microplasma 19 at the time tn. On the other hand, if there is no change in the second detection results 52a to 52c while scanning the mass spectrum, it can be guaranteed that the mass spectrum 51c obtained at the time tn reflects the state of the microplasma 19 at the time tn. In order to guarantee the reliability of the mass spectrum 51, the generating device 57b may generate all of the second detection results 52 while acquiring the mass spectrum 51 as the analysis data 53 in synchronization. The generating device 57b may verify that all the second detection results 52a-52c are the same while acquiring the mass spectrum 51, and may generate only the mass spectrum 51c when all the second detection results 52a-52c are the same as the second detection result 52c in synchronization with the second detection result 52c as the analysis data 53, or may discard the mass spectrum 51c when the condition is not satisfied. The generating device 57b may store the analysis data 53 thus generated in the memory 55, or may output it to an external server or process controller 105 via the communication device 57d.

[0036] That is, this gas analyzer 1 includes a sample chamber 12 that generates a common plasma 19 serving as an ion source and a light emission source separately from the process 102, and includes a first detector 20 and a second detector 80 whose route is fixed in advance to the sample chamber 12. Therefore, a serial first detection result 51 and a parallel second detection result 52 for the common plasma 19 generated in the sample chamber 12 can be acquired synchronously, and the generation device 57b can generate and output them as analytical data 53 by relating them. Therefore, by checking the fluctuation of the parallel second detection result 52 during the time interval during which the serially acquired first detection result 51 is obtained, it is possible to verify that the first detection result 51 is information from the same conditions, for example, the process under the same conditions or the plasma 19 maintained under the same conditions, and more reliable analytical results can be obtained.

[0037] Also, a minute microplasma 19 is generated in the sample chamber 12 of the gas analyzer 1. Therefore, the volume of the common ion source and light emission source to be detected by the first detector 20 and the second detector 80 can be reduced, and the bias in the plasma can be reduced, and the first detection result 51 and the second detection result 52 for the same target can be obtained. Furthermore, it is also possible to limit the mass spectrum 51 obtained serially to a region of interest (ROI) 51r, and it is also possible to confirm wide-range information with the second detection result 52 obtained in parallel, and to serially obtain the ROI over time with the first detection result 51. That is, as shown in FIG. 2, the first detection result 51 may include a mass spectrum 51c, and in particular, may include only the mass spectrum 51c limited to the ROI 51r. Therefore, it is possible to obtain more accurate analysis results for the ROI even at short time intervals while confirming wide-range information.

[0038] The PLC 50 may further include a plasma generation control device 57a that manages the generation state of the microplasma 19 via the plasma controller 16, an ROI control device 57c that controls the filter 25 of the first detector 20 so as to obtain a mass spectrum within a desired ROI range, and a communication control device 57d for communicating with the process controller 105 and / or an external server, etc., via wired and / or wireless communication.

[0039] The PCL 50 may further include an analysis device (analysis unit, analysis function) 70 that analyzes components (elements) contained in the sample gas 9 based on analysis data 53 including the first detection result 51 and the second detection result 52. The analysis device 70 may include a first analyzer (first analysis unit) 71 that analyzes the sample gas 9 based on the first detection result 51 and the second detection result 52 synchronized with the first detection result 51 at a time interval defined by the gas analysis device 1.

[0040] As described above, in terms of spectral interference, the first detector (MS) 20 cannot separate elements (components) having the same mass-to-charge ratio m / z, and the second detector (OES) 80 has difficulty separating elements (components) having spectra with the same or close frequencies. Conversely, components that cannot be separated in the first detection result 51 of the first detector 20 can be separated in the second detection result 52 of the second detector 80, and components that cannot be separated in the second detection result 52 of the second detector 80 may be separated in the first detection result 51 of the first detector 20. Furthermore, in the analysis device 1 of this example, analysis data 53 is obtained that combines the first detection result 51 and the second detection result 52 that are synchronized in time and have high reliability. Therefore, in the first analyzer 71, by analyzing these data in a coordinated manner, it becomes possible to analyze the components of the sample gas 9 with higher accuracy.

[0041] The analysis device (cooperative control module) 70 performs a process of acquiring an analysis result by processing the detection result 51 of the first detector 20 and the detection result 52 of the second detector 80 in parallel or at a time interval defined by the gas analysis device 1. In this process, since the gas analysis device 1 includes an electron ionization device 15 in addition to the sample chamber 12, the following processing methods (processing modes) may be selectable, and the analysis device 70 may include a second analyzer 72 that selects one of the following modes M1, M2, and M3 to perform the analysis. (1) Detection of ionized components in the plasma 19 by the first detector 20 and emission analysis by the second detector 80 are carried out in parallel (first mode, M1). (2) Detection of components by ionization of gas derived from plasma 19 by electron ionizer 15 using first detector 20 and optical emission analysis using second detector 80 are performed in parallel (second mode, M2). (3) Detection of components by the first detector 20 without passing through plasma 19, by ionizing the sample gas 9 supplied via the sample input 3b with the electron ionizer 15, and optical emission analysis of the plasma 19 by the second detector 80 are performed in parallel (third mode, M3). By selecting or combining these processes, the components, state, concentration of each component, and time-dependent changes of the sample gas 9 can be measured with high accuracy.

[0042] In modes other than the third mode, the sample input 3b is closed by the upstream valve 5b. When the inside of the process chamber 101 is at a negative pressure (vacuum) to such an extent that it is difficult to generate plasma 19, the sample input 3a may be closed by the upstream valve 5a and the sample gas 9 may be supplied from the sample input 3b and ionized by the electron ionizer 15. In this case, the microplasma 19 is not formed, and therefore the detection result 52 by the second detector (OES) 80 is not obtained.

[0043] The process monitor (process monitoring device, process monitoring system) 100 includes a process controller (process control device) 105 that controls the process 102 based on the results of analysis by a gas analyzer 1 of a sample gas 9 supplied from a process chamber 101 in which a plasma process 102 is performed. The process controller 105 may include computer resources such as a CPU and memory, and may be operated by a control program (program product) 109. The process controller 105 may include an analyzer 70 having a configuration common to that of the PLC 50, and may receive analysis data 53 from the gas analyzer 1 to analyze the sample gas 9 and control one or more processes 102 performed by the process chamber 101.

[0044] The process controller 105 includes an end point controller 110 that determines the end point of at least one plasma process 102 based on the result of detecting (measuring) a sample gas 9 containing by-products of the plasma process by a gas analyzer 1. The at least one plasma process 102 may include at least one of etching, film formation, and cleaning. In the process monitor 100, a plasma 19 is generated in a sample chamber 12 managed by the gas analyzer 1, which is independent of the process chamber 101. This makes it possible to synchronize and correlate the detection of components by a first detector (mass analyzer, MS) 20 and the detection of components by a second detector (OES) 80 with high accuracy, and to perform not only the presence or absence of by-products of the process 102 but also a qualitative analysis with high accuracy. Therefore, the process controller 105 can appropriately control the plasma process 102 based on the analysis.

[0045] FIG. 3 shows an outline of the control of the plasma process 102 by the process controller 105 in a flow chart. In step 121, the process 102 in the process chamber 101 is started. At the same time, or before or after this, in step 122, the process controller 105 starts the analysis of the sample gas 9 by the gas analyzer 1. In step 123, the gas analyzer 1 detects the components of the plasma 19 in the sample chamber 12 by the first detector (MS) 20 and the second detector (OES) 80, and generates the analysis data 53 by synchronizing the first detection result 51 and the second detection result 52 and relating them. In the second detection result 52, information on a wide range of components can be obtained by the emission spectrum acquired in parallel at once. In the first detection result 51, only the mass spectrum (MS) limited to the region of interest (ROI) can be acquired, and information with high accuracy and high sensitivity can be obtained.

[0046] In step 124, the first analyzer 71 analyzes the components of the sample gas 9 based on the analysis data 53. If it is determined in step 125 that switching of the measurement mode is necessary, in step 126, any one of the above-mentioned first mode (M1), second mode (M2), and third mode (M3) may be selected.

[0047] In step 127, the end point controller 110 of the process controller 105 determines the status and end time of the process 102 based on the analysis result of the sample gas 9, and when it determines that the conditions for ending the process 102 are met, ends the process 102 in step 128. The end point controller 110 may also determine the end of the process 102 based on the detection result of the gas analyzer 1 of the by-products of the plasma process 102. Thereafter, preparations are made to start the next process, and the processes are sequentially repeated to manufacture the product.

[0048] FIG. 4 shows another example of the process monitoring apparatus 100. This process monitoring apparatus 100 includes another example of the gas analyzer 1. In this gas analyzer 1, the spectroscopic analysis unit 85 of the second detector 80 is arranged so as to be directly connected to the light-transmitting and dielectric wall structure 12a of the sample chamber 12. Therefore, the light from the plasma 19 in the sample chamber 12 can be spectroscopically analyzed without passing through an optical fiber, and the spectroscopic analysis result can be obtained with higher accuracy. In addition, by arranging the spectroscopic analysis unit 85 adjacent to or coaxially with the wall 12a to which RF for generating the plasma is supplied, the plasma 19 can be generated so that the inner surface of the wall 12a is treated with the plasma 19. Therefore, it is possible to prevent a situation in which the inner surface of the wall 12a is contaminated by the derivative of the plasma 19 and the light emission becomes difficult to see.

[0049] This gas analyzer 1 has a first path 151 that supplies a flow of ionized gas (ion flow) 17 to a first detector 20 from an opening 18 provided at one end of the sample chamber 12, and a second path 152 that supplies light for spectroscopic analysis by a second detector 80 from the other end of the sample chamber 12. Light for spectroscopic analysis can be obtained from the opposite direction to which the ion flow 17 flows, and unexpected fluctuations in the second detection result 52 of the second detector 80 can be suppressed.

[0050] FIG. 5 shows yet another example of a process monitoring system 100. The process monitoring system 100 includes yet another example of a gas analyzer 1. The sample chamber 12 of the gas analyzer 1 is cylindrical with a light-transmitting, dielectric side wall 12b, and a light-collecting element 81 is attached to the side wall 12b for directing light via an optical fiber 82 to a spectroscopic analysis unit 85 of a second detector 80. Thus, the gas analyzer 1 includes a first path 151 for supplying an ionized gas flow (ion flow) 17 to a first detector 20 from an opening 18 provided at one end along a first axis (central axis) 155 of the sample chamber 12, and a third path 153 for supplying light for spectroscopic analysis by the second detector 80 in a direction perpendicular to the first axis 155 of the sample chamber 12. The plasma 19 generated in the cylindrical chamber 12 can be accessed from the side by the third path 153. Therefore, the second detector 80 is capable of performing optical emission analysis (spectroscopic analysis) using the light emitted from the atomized sample in the center of the plasma 19, and can obtain the detection result 52 with higher accuracy.

[0051] The location where the spectroscopic analysis unit 85 is placed to obtain the light emission from the plasma 19 or the location where the optical fiber 82 is attached is not limited to the above.

[0052] The above discloses a gas analyzer having a sample chamber having a dielectric wall structure and into which only sample gas to be measured flows, a plasma generation mechanism that generates plasma in the sample chamber, the pressure of which is reduced, by an electric field and / or a magnetic field via the dielectric wall structure, and an analysis unit (sensor group) that analyzes the sample gas via the generated plasma. The analysis unit includes a first analyzer (first detector), such as a mass analyzer, that filters ionized gas in the plasma, and a second analyzer (second detector), such as an optical emission spectrometer, that performs spectroscopic analysis of ions in the plasma in the sample chamber. This analysis device can perform spectroscopic analysis of the ion species and concentration of the plasma, which is the ion source of the first analyzer, by the second analyzer. For this reason, a common ionized sample can be analyzed by different methods simultaneously in parallel or with a limited time interval (latency) in the gas analyzer, and the analysis results by the different methods can be obtained in real time as the analysis results of one analysis device. That is, the analysis unit may include a third analyzer that acquires analysis results obtained by processing the analysis results of the first analyzer and the second analyzer in parallel or at a time interval specified by the gas analysis device. That is, the results of capturing the ionized gas in the plasma in the sample chamber using different analysis methods without time lag can be compared to analyze the components and concentrations of the sample gas with high accuracy, including temporal fluctuations.

[0053] Since a microplasma is formed in the sample chamber, the size of the light source is small enough for the subject of the optical emission spectroscopy analysis, and stable analysis results can be obtained. The second analyzer may include a unit that receives light from the plasma in the sample chamber through a highly light-transmitting dielectric wall structure, and the inner surface of the wall structure is constantly refreshed by the plasma, so that degradation of analytical performance due to dirt or the like can be suppressed. Furthermore, the second analyzer may be a spectroscopic analyzer connected to the sample chamber through an optical fiber, and in order to eliminate the influence of the optical fiber, the second analyzer may include a spectroscopic analyzer that obtains optical emission from the sample chamber without using the optical fiber. The first analyzer may include an electron ionization unit that generates electrons for ionizing the sample gas.

[0054] Further disclosed above is a process monitoring system having a gas analyzer, which is an example of a system having a gas analyzer and a process chamber in which a plasma process is performed and in which a sample gas is supplied to the gas analyzer.

[0055] The above also discloses a method for analyzing components of a sample gas using a gas analyzer. This method includes obtaining analysis results obtained by processing the analysis results of the first analyzer and the second analyzer in parallel or at a time interval specified by the gas analyzer. Even if there are components that cannot be separated by mass analysis because they have the same charge ratio, highly accurate analysis results can be obtained by analyzing the mass analysis results while taking into account the ionization type obtained by spectroscopic analysis, and there are many other effects that can be obtained by cooperation between mass analysis and spectroscopic analysis. When the first analyzer includes an electronic ionization unit that generates ions for ionizing the sample gas, the following measurement method may be included. (1) Analysis of the ionized gas in the plasma by the first analyzer and analysis of the gas in the plasma by the second analyzer are performed in parallel. (2) Analysis of the gas derived from the plasma ionized by the electronic ionization unit by the first analyzer and analysis of the gas in the plasma by the second analyzer are performed in parallel. (3) Analyzing the gas ionized by the electron ionization unit by the first analyzer without using plasma, and analyzing the gas in the plasma by the second analyzer in parallel.

[0056] Further disclosed herein is a method for controlling a system having a process chamber performing a plasma process, the system having an analyzer as described above, where only sample gas from the process chamber flows into the sample chamber, the method including controlling a plasma process performed in the process chamber based on measurements from the gas analyzer.

[0057] Although an example of a mass filter employing a quadrupole type as the filter 25 of the first detector 20 has been described above, this filter 25 may be of another type, such as an ion trap or Wien filter.

[0058] Furthermore, while particular embodiments of the present invention have been described above, various other embodiments and modifications may be conceived 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. [Explanation of symbols]

[0059] 1 Gas analyzer, 5 Gas input device, 9 Sample gas 12 Sample chamber, 13 Plasma generation mechanism, 19 Plasma 20 first detector, 80 second detector

Claims

1. a sample chamber having a dielectric wall structure into which a sample gas to be measured flows; a plasma generation mechanism that generates plasma in the sample chamber under reduced pressure by an electric field and / or a magnetic field via the dielectric wall structure; a gas input device configured to allow only the sample gas from the process to flow into the sample chamber; an electron ionization device configured to receive a portion of the sample gas from the gas input device and to electron ionize the portion of the sample gas; a first detector configured to filter the electron-ionized gas and output a first detection result for detecting components in the sample gas; a second detector configured to analyze the emission of ions in the plasma in the sample chamber to output a second detection result for detecting components in the sample gas; a gas analyzer having an exhaust system configured to create a negative pressure within the sample chamber and within a housing containing the electron ionizer and the first detector.

2. In claim 1, The first detection result and the second detection result are output in synchronization as analysis data. A gas analyzer having a generator for generating a gas.

3. In claim 2, A gas analyzer, wherein the first detection result includes a mass spectrum of the first detector, and the second detection result includes an emission spectrum of the second detector.

4. In claim 3, A gas analyzer, wherein the mass spectrum includes a mass spectrum limited to a region of interest.

5. In any one of claims 1 to 4, the sample chamber is integral with the housing; a light guide for providing light for spectroscopic analysis by said second detector from an end of said sample chamber different from said housing;

6. In any one of claims 1 to 4, the dielectric wall structure comprises at least one of quartz, aluminum oxide, and silicon nitride; a light guide that directs light from the plasma in the sample chamber through the dielectric wall structure to the second detector;

7. In claim 6, the plasma generating mechanism includes a coil-shaped RF supply mechanism attached to a side of the sample chamber; The gas analyzer, wherein the light guide is mounted in the sample chamber coaxially with the coiled RF supply mechanism.

8. In any one of claims 1 to 4, The gas analyzing apparatus, wherein the second detector includes an optical emission analyzer connected to the sample chamber via an optical fiber.

9. In any one of claims 1 to 4, The sample chamber has a total length of 1-100 mm and a diameter of 1-100 mm.

10. A process monitoring device comprising the gas analyzer according to any one of claims 1 to 4.

11. A gas analyzer according to any one of claims 1 to 4; a process chamber in which a plasma process is performed, the process chamber providing the sample gas to the gas analyzer.

12. In claim 11, The system further comprises a process controller for controlling at least one plasma process performed in the process chamber based on measurements from the gas analyzer.

13. In claim 12, The system, wherein the process control device includes a device for determining an endpoint of the at least one plasma process based on measurements of by-products of the at least one plasma process by the gas analyzer.

14. 1. A method of controlling a system having a gas analyzer, comprising: the gas analyzer includes: a sample chamber having a dielectric wall structure into which a sample gas to be measured flows; a plasma generation mechanism that generates plasma in the sample chamber, the pressure of which is reduced, by an electric field and / or a magnetic field via the dielectric wall structure; a gas input device configured to allow only the sample gas from a process to flow into the sample chamber; an electron ionizer configured to receive a portion of the sample gas from the gas input device and to electron ionize the portion of the sample gas; a first detector configured to filter the electron ionized gas and output a first detection result for detecting components in the sample gas; a second detector configured to analyze light emission of ions in the plasma in the sample chamber and output a second detection result for detecting components in the sample gas; and an exhaust device configured to create a negative pressure in the sample chamber and in a housing containing the electron ionizer and the first detector; The method includes synchronously outputting a first detection result from the first detector and a second detection result from the second detector.

15. In claim 14, The method, wherein the synchronous outputting includes a mass spectrum of the first detector as the first detection result and an emission spectrum of the second detector as the second detection result.

16. In claim 15, The method, wherein the mass spectrum comprises a mass spectrum limited to a region of interest.

17. In any one of claims 14 to 16, the system includes a process chamber for performing a plasma process, the process chamber being capable of supplying a sample gas to the gas analyzer via the gas input device; The method comprises: and controlling a plasma process performed in the process chamber based on detection results of the gas analyzer that generated plasma in the sample chamber independent of the process chamber.

18. In claim 17, The method, wherein controlling the plasma process includes determining an endpoint of at least one plasma process based on detection of by-products of the at least one plasma process by the gas analyzer.

19. In claim 18, The method, wherein the at least one plasma process comprises at least one of etching, film deposition, and cleaning.

20. A program for controlling a system including a gas analyzer according to the method of controlling the system by a computer, the program comprising: A program having instructions for carrying out the method according to any one of claims 14 to 16.

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