Gas analyzer

Abstract

The gas analyzer (1) comprises a sample chamber (40) into which a sample gas (9) to be measured flows, a plasma generation circuit (10) that generates plasma (8) in the sample chamber (40), and an analyzer 30 that analyzes the sample gas via the plasma (8) generated in the sample chamber. The plasma generation circuit (10) includes a plasma induction circuit (13) and an RF power supply circuit (11) configured to supply RF power to the plasma induction circuit. The plasma induction circuit is directly incorporated as at least part of the resonant components of the RF power supply circuit.

Description

[Technical Field]

[0001] The present invention relates to a gas analyzer equipped with a plasma generator. [Background technology]

[0002] A Class E power oscillator (PO) is disclosed in U.S. Public Release 2020 / 0059198. This Class E PO includes a first inductor, a switch, a first capacitor, a resonant circuit, and a feedback network. The first inductor is connected in series with a first power supply. The switch is connected between the first inductor and a primary common node. The first capacitor is connected between the first inductor and a primary common node. The resonant circuit includes a second inductor, a second capacitor, and a resistor. The second inductor is connected between the first inductor and a primary common node. The second capacitor is connected between the first inductor and a primary common node and is connected in series with the second inductor. The resistor is connected between the first inductor and a primary common node and is connected in series with the second inductor. The feedback network is connected between the switch and a feedback node. The feedback node is located between the second inductor and the second capacitor. The feedback network is configured to periodically switch on and off based on the resonant frequency of the resonant circuit.

[0003] International Publication WO2020 / 196452 ​​discloses a gas analyzer. This gas analyzer includes a sample chamber equipped with a dielectric wall structure into which only the sample gas to be measured is introduced; a plasma generation mechanism that generates plasma in the depressurized sample chamber using an electric and / or magnetic field applied through the dielectric wall structure; and an analysis unit that analyzes the sample gas through the generated plasma. This makes it possible to provide a gas analyzer that can accurately analyze even sample gases containing corrosive gases over a long period of time.

[0004] As shown in Figure 1, an existing system 101 for generating RF energy for plasma generation includes a frequency reference source 102, a power amplifier 103, and a plasma generation load circuit 104 connected to the power amplifier via an impedance-matched transmission line 105. The parameters of the plasma generation load circuit 104 vary depending on environmental conditions, and the use of a plasma chamber causes an impedance mismatch between the transmission line 105 and the power amplifier 103. This impedance mismatch limits the performance and lifespan of the system 101 and necessitates the addition of a complex and expensive matching mechanism with limited reliability and performance range. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] One of the challenges is to suppress or prevent impedance mismatch in plasma generators using a simple mechanism. [Means for solving the problem]

[0006] One aspect of the present invention is a gas analyzer comprising a sample chamber into which a sample gas to be measured flows, a plasma generation circuit configured to generate plasma within the sample chamber, and an analyzer configured to analyze the sample gas via the plasma generated within the sample chamber. The plasma generation circuit includes a plasma induction circuit including at least one of a plasma induction coil and a capacitor, and an RF power supply circuit configured to supply RF power to the plasma induction circuit, wherein the plasma induction circuit is directly incorporated (integrated) as at least a part of the resonant components of the RF power supply circuit.

[0007] The inventors of this application aim to provide a gas analyzer that can be offered in a very compact form. In such a gas analyzer, the inventors have found that by directly integrating the plasma induction circuit into the RF power supply circuit without using transmission lines, the plasma generation circuit can be miniaturized, and the impedance matching mechanism can be omitted. Furthermore, because the plasma induction circuit is coupled to the plasma chamber (sample chamber) (as induction and capacitance), if the parameters of the plasma chamber change continuously during normal operation, the effective parameters of the plasma induction circuit change and are directly fed back to adjust the oscillation frequency of the RF power supply circuit without using an impedance matching mechanism. This makes it possible to provide a self-adjusting and self-starting plasma generation circuit. By integrating the plasma induction circuit as part of the actual LC parameters for determining the oscillation frequency, the oscillation frequency is determined autonomously by the effective LC parameters. This self-adjusting capability allows the design to adapt to any variations in the mechanical properties of the chamber without the use of a special impedance matching circuit.

[0008] The RF power supply circuit may include an E-type (Class E) power oscillator. The RF power supply circuit may also include an electrically controlled switch, a first capacitor connected in parallel with the electrically controlled switch, a resonant circuit connected in parallel with the electrically controlled switch, the resonant circuit including a plasma induction circuit as at least part of an inductor and a second capacitor, a third capacitor, and a feedback circuit configured to obtain a feedback signal from the electrically controlled switch from a feedback node between the plasma induction circuit and the third capacitor.

[0009] The gas analyzer may further comprise a base on which a sample chamber, a plasma generator, and the analyzer are assembled as a single module, and may be provided as an integrated analyzer module and / or a portable or handheld analyzer. The gas analyzer may further comprise an exhaust system configured to exhaust from the sample chamber, which may be assembled on the base on which the sample chamber, plasma generator, and analyzer are assembled as a single module. The sample chamber, plasma generator, analyzer, and exhaust system may be integrated on or within the base as a single module. The gas analyzer may further comprise a first detector configured to detect "ionized gas" filtered from the plasma output from the sample chamber. The gas analyzer may further comprise a second detector configured to analyze the emitted light (luminescence) of ions in the plasma within the sample chamber.

[0010] One different aspect of the present invention is a system comprising the gas analyzer described above and a sampling device configured to supply a sample gas to be measured to a sample chamber. This system may further include a process chamber from which a plasma process is performed, such as substrate etching, CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), or one or more processes related to semiconductor manufacturing, from which the sample gas is supplied to the gas analyzer. The compact gas analyzer of the present invention can be easily and economically installed or mounted on a process apparatus, process controller, and / or process monitor. This system may further include a process monitoring device that monitors at least one process performed in the process chamber based on the measurement results of the gas analyzer. This system may further include a process control device that controls at least one process performed in the process chamber based on the measurement results of the gas analyzer.

[0011] One further different aspect of the present invention is a system comprising a plasma generation chamber and a plasma generation circuit. The plasma generation circuit comprises an electrically controlled switch, a first capacitor connected in parallel with the electrically controlled switch, and a resonant circuit connected in parallel with the electrically controlled switch, the resonant circuit comprising a plasma induction circuit for generating plasma in the plasma generation chamber and a third capacitor. The plasma induction circuit is incorporated as at least part of an inductor and a second capacitor for directly forming the resonant circuit. Furthermore, the system comprises a feedback circuit for obtaining a feedback signal from the electrically controlled switch from a feedback node between the plasma induction circuit and the third capacitor. The system may further include a sampler (sampling line, sampling device) configured to supply a sample gas to be measured to the plasma generation chamber, and an analyzer for analyzing the sample gas through the plasma generated in the plasma generation chamber. The sampler may be configured to supply a sample gas supplied from a process to be monitored, and the system may further include a process monitor for monitoring and controlling the process according to the measurement results of the analyzer. [Brief explanation of the drawing]

[0012] Embodiments of this specification will be better understood from the following detailed description with reference to the drawings: [Figure 1] Figure 1 shows an example of a prior embodiment of a plasma generation circuit. [Figure 2] Figure 2 shows one embodiment of the system including the plasma generation circuit of the present invention. [Figure 3] Figure 3 shows one embodiment of the system including the plasma generation circuit of the present invention. [Figure 4] Figure 4 shows the reference circuit for a Class E power oscillator (PO). [Modes for carrying out the invention]

[0013] The embodiments and various features and advantageous details herein are better described with reference to the non-limiting embodiments illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as not to unnecessarily obscure the embodiments herein. The examples used herein are merely intended to facilitate understanding of how the embodiments herein may be carried out and to further enable those skilled in the art to carry out the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0014] Figure 2 shows the configuration of a process monitoring system 70 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 71 in which one or more plasma processes 72 are performed. Examples of plasma processes 72 performed in the process chamber 71 include processes for forming various films or layers on a substrate, processes for etching a substrate, CVD (Chemical Vapor Deposition) and / or PVD (Physical Vapor Deposition). Furthermore, the plasma process 72 is not limited to processes related to semiconductor manufacturing, but may also be a process for laminating various thin films on an optical component such as a lens or filter as a substrate.

[0015] For example, in the semiconductor field, the structure of semiconductor chips has become increasingly three-dimensional in recent years due to demands for larger memory capacity, faster logic, and lower power consumption. As a result, semiconductor process control is facing problems such as increased process complexity, higher atomic-level quality requirements, and rising measurement and monitoring costs. Monitoring gases containing reactants and by-products is essential for process matching, measuring transition points during film deposition, and detecting endpoints during etching.

[0016] The process monitor (process monitoring device, process monitoring system) 70 includes a process controller (process controller device) 75 that controls the process 72 according to the result of analyzing the sample gas 9 supplied from the process chamber 71 in which the plasma process 72 is performed, using the gas analyzer 1. The process controller 75 includes computer resources such as a CPU and a memory, and can operate according to a control program (program product). The process controller 75 may execute control of one or more processes 72 executed in the process chamber 71.

[0017] In the process monitoring system 70 using the gas analyzer 1 according to the present embodiment, innovative process control can be performed by performing monitoring in real time even in a harsh environment and providing highly reliable measurement results. The gas analyzer 1 functions as a total solution platform developed to dramatically improve throughput and maximize yield in semiconductor chip manufacturing. As described above, since the gas analyzer 1 according to the present embodiment is provided as one module with a small (extremely small) installation area, it can be directly connected to the chamber 71 or used on site.

[0018] The gas analyzer 1 includes a chamber (sample chamber, plasma generation chamber, sampling chamber) 40 into which a sample gas 9 to be measured flows, a plasma generation circuit (plasma generation circuit) 10 configured to generate (produce) plasma 8 in the sample chamber 40, and an analyzer (analyzer, analysis unit) 30 configured to analyze the sample gas 9 to be measured through the plasma 8 generated in the sample chamber 40. The sample chamber 40 includes a dielectric wall structure 41 and receives only the inflow of the sample gas 9 to be measured supplied from the process chamber 71 through the sampling device (sampler) 79. The plasma generation circuit 10 includes an RF power supply circuit 11 and a plasma induction circuit 13 directly incorporated as part of the RF power supply circuit 11. The plasma induction circuit (plasma induction circuit, high-frequency supply mechanism, RF supply mechanism, RF supply device) 13 can include an inductance (such as a plasma induction coil), an induction capacitor, or a combination of an inductance and a capacitor for applying a high-frequency electric field and / or magnetic field through (via) the dielectric wall structure 41 to generate (produce) plasma 8 in the depressurized sample chamber 40. The device 1 can further include a control electrode 45 in the sample chamber 40 to control the floating potential Vf of the plasma 8.

[0019] The gas analyzer 1 according to this embodiment may be a mass spectrometer type, and the analyzer 30 includes a filter unit (filter, in this embodiment, a quadrupole filter) 20 for filtering the sample gas (sample gas ions) 7 generated and ionized as plasma 8 in the sample chamber 40 according to the mass-to-charge ratio, a focus electrode (ion extraction optical system) 25 for drawing a part of the plasma 8 as an ion flow 7, a detector unit (detector, first detector) 31 for detecting the ions (ionized gas) filtered from the plasma flow 7, and a vacuum container (housing) 29 that houses the filter 20, the electrode 25, and the detector 31. The filter 20 may be of other types such as an ion trap, TOF (time-of-flight type), etc.

[0020] The analyzer 30 may include an Optical Emission Spectrometer (OES, second detector) 35 configured to analyze the emitted light (luminescence) of ions in the plasma 8 within the sample chamber 40. The gas analyzer 1 includes a light-receiving element or light-collecting element 37, such as an objective lens, attached to the translucent dielectric wall structure 41 of the sample chamber 40, an optical fiber 36 that guides light from the light-collecting element 37, and a spectroscopic analysis unit (OES, OES detector device) 35 that spectroscopically analyzes the light supplied from the optical fiber 36. The spectroscopic analyzer of the OES 35 may be any detector used in an OES, such as a sequential detector or a multi-channel detector.

[0021] The gas analyzer 1 further includes an exhaust system 60 that maintains the inside of the housing 29 under appropriate negative pressure conditions (vacuum conditions). In this embodiment, the exhaust system 60 includes a turbomolecular pump (TMP) 61 and a Roots pump 62. The exhaust system 60 is a dual-type configuration that also controls the internal pressure of the sample chamber 40 using an intermediate negative pressure stage formed between the TMP 61 and the Roots pump 62.

[0022] In the sample chamber 40 depressurized by the exhaust system 60, only the sample gas 9 flows in from the process chamber 71 via the sampling device (sampler) 79, and in the sample chamber 40, the plasma 8 is formed only by the sample gas 9. The chamber 40 is designed to generate the microplasma 8 in the intermediate region that is neither a macro plasma nor a nano plasma. Generating the microplasma 8 for analysis is one of the factors for realizing this compact gas analyzer 1. Examples of the microplasma 8 include plasmas in a region of about several mm to 100 μm. To generate the plasma 8 of this size, the plasma generation circuit 10 generates the plasma 8 for analysis using only the sample gas 9 without using an assist gas (support gas) such as argon gas. Although the microplasma 8 is small, it can supply the filter 20 with a sufficient amount of ionized gas 7 to be detected by the first detector 31 such as a Faraday cup (FC), and has a sufficient volume to be detected by the second detector (OES) 35. The wall body 41 of the sample chamber 40 is composed of a dielectric member (dielectric), and examples include dielectrics with high plasma resistance such as quartz, aluminum oxide (Al2O3), and silicon nitride (SiN3).

[0023] The sample chamber 40 is a small chamber suitable for generating the microplasma 8. For example, the sample chamber 40 may have an overall length of 1 to 100 mm and a diameter of 1 to 100 mm. The overall length and diameter may also be 5 mm or more, 10 mm or more, 80 mm or less, 50 mm or less, or 30 mm or less. The capacity of the sample chamber 40 is 1 mm 3 or more, and / or 10 5 mm 3 or less. The capacity of the sample chamber 40 may also be 10 mm 3 or more, 30 mm 3 or more, or 100 mm 3 or more. The capacity of the sample chamber 40 is 10 4 mm 3 or less, 10 3 mm 3The following is also acceptable. In a space of this size, it is easy to control the potential (electric field) within the chamber space using the electrodes 45 placed inside the chamber. Miniaturizing the sample chamber 40 in this way is one of the advantages that allows this gas analyzer 1 to be provided in a compact modular structure. Furthermore, in this gas analyzer 1 that corresponds to this small sample chamber 40, the plasma generation circuit 10 has a simplified configuration, as will be described in detail later, resulting in a smaller footprint. This circuit configuration also contributes to providing a compact gas analyzer 1.

[0024] The internal pressure of the sample chamber (container) 40 is controlled to an appropriate negative pressure using the exhaust system 60 shared with the filter 20. An independent exhaust system or an exhaust system shared with the process equipment may also be used. The internal pressure of the sample chamber 40 should be a pressure at which microplasma 8 is easily generated, for example, in the range of 0.01 to 1 kPa. If the internal pressure of the process chamber 71 is controlled or maintained to a pressure of 1 to several hundred Pa, the internal pressure of the sample chamber 40 can be controlled to a lower pressure, for example, 0.1 to several tens of Pa, and may be controlled to be above 0.1 Pa, above 0.5 Pa, below 10 Pa, or below 5 Pa. For example, the pressure inside the sample chamber 40 may be reduced to about 1 to 10 mTorr (or 0.13 to 1.3 Pa). By reducing the pressure inside the sample chamber 40 to the above degree, it becomes possible to generate microplasma 8 at a low temperature using only the sample gas 9.

[0025] In the process monitoring system 70 using the gas analyzer 1, the sample gas 9 supplied from one or more process chambers 71 where plasma processing is performed, via a sampling device 79, is the target of monitoring. Within the sample chamber 40, by supplying high-frequency power under appropriate conditions, plasma 8 can be maintained simply by introducing the sample gas 9 without using arc discharge or a plasma torch. By not requiring support gases such as argon gas, it is possible to generate ionized plasma 8 using only the sample gas 9 (simply, purely), and to analyze this ionized plasma 8 with the analyzer 30. In other words, it is possible to provide a gas analyzer 1 that has high measurement accuracy for the sample gas 9 and can also quantitatively measure components not limited to gas components. As a result, the process monitor (process monitoring device) 70 equipped with the gas analyzer 1 can stably and accurately monitor the internal state of the process chamber 71 of the process apparatus over a long period of time.

[0026] In the process monitor 70, the plasma 8 of the sample gas 9 is generated in a sample chamber 40 dedicated to gas analysis, separate from the process chamber 71. Therefore, the sample chamber 40 can generate microplasma 8 under conditions different from those of the process chamber 71, which are suitable for sampling and gas analysis. For example, even when no process plasma or cleaning plasma is generated in the process chamber 71, the internal state of the process chamber 71 can be monitored by plasmaizing the sample gas 9 (by using the plasmaized sample gas). The sample chamber 40 may be a small chamber (miniature chamber) suitable for generating microplasma 8, for example, a few millimeters to tens of millimeters in size. Because the volume of the sample chamber 40 is small, the entire analyzer 1 can be made smaller and lighter. A gas analyzer 1 suitable for real-time measurement can be provided. The gas analyzer 1 may also be a portable or handheld type.

[0027] The gas analyzer 1 includes a control unit (central control unit) 50 and a local control unit (local controller) 51. The central control unit 50 may have the functions of the local control unit 51. The control unit (controller) 50 includes a filter control unit (filter control function, filter controller, or filter control device) 53 that controls the filter unit (filter) 20, a detector control unit (detector control function, detector controller, or detector control device) 54 that controls the detectors 31 and 35, and a management control unit (management device, management controller, manager, management function, or management unit) 55 that controls the data input / output of the gas analyzer 1, and data analysis as needed. The controller 50 may have computer resources including memory 57 and a CPU 58, and the functions of the controller 50 may be provided by a program 59 recorded in memory 57. The program (program product) 59 may be provided by recording the program on a suitable recording medium.

[0028] The local controller 51 has the following functions: 51a, which controls the on / off state of the plasma generation circuit (plasma generation unit) 10; 51b, which controls the voltage supplied to the control electrode 45 to control the stray potential of the plasma 8 (plasma potential control unit, potential control device, potential controller, or voltage controller); and 51c, which controls the internal pressure of the sample chamber 40 using a pressure control valve 65 provided in the line connected to the exhaust system 60. By controlling these functions, even if the type of process performed in the process chamber 71 is changed and / or the state of the process is changed based on a request from the control unit 75 of the management device 70, the self-regulating plasma generation circuit 10 can stably generate plasma 8 in the sample chamber 40. Therefore, the process monitoring device 70, including the gas analyzer 1, can continuously analyze the sample gas 9 and monitor one or more processes.

[0029] The gas analyzer 1 includes a base 5 for integrating a sample chamber 40, a plasma generator 10, an analyzer 30, control devices 50 and 51, and an exhaust system 60 as a single module. The base 5 may be a chassis or base plate on which the sample chamber 40, plasma generator 10, analyzer 30, control devices 50 and 51, and exhaust system 60 are assembled, and these can be installed and handled as a single module. The base 5 may also be a housing (main body) that accommodates the sample chamber 40, plasma generator 10, analyzer 30, control devices 50 and 51, and exhaust system 60, and may be transported or installed as a single unit in the field as a portable, mobile, handheld, laptop, and / or desktop device. A typical example of the size of the gas analyzer is 300-400 mm in height, 250-350 mm in width, and 350-450 mm in depth, but is not limited to these dimensions.

[0030] The plasma induction circuit (induction circuit) 13 of the plasma generation circuit 10 generates plasma 8 in the sample chamber (plasma generation chamber) 40 using an electric field and / or magnetic field applied through the dielectric wall structure 41, without using electrodes or a plasma torch. An example of the plasma induction circuit 13 may include components or circuit elements such as coils and / or capacitors for a mechanism to excite the plasma 8 with high-frequency (or radio frequency (RF)) power. The plasma induction mechanism (method) may be inductively coupled plasma (ICP), dielectric barrier discharge (DBD), electron cyclotron resonance (ECR), or other methods using RF power.

[0031] Figure 3 shows an example of a system (gas analyzer) 1 including a plasma generation chamber (sample chamber) 40 and a plasma generation circuit 10. An example of the plasma generation circuit (plasma generation circuit, plasma generation unit, plasma generator) 10 includes a plasma induction circuit 13 which includes at least one of a plasma induction coil 13a and a capacitor 13b for inducing or generating plasma in the sample chamber 40. The plasma generation circuit 10 also includes an RF power supply circuit 11 configured to supply RF power to the plasma induction circuit 13. The plasma induction circuit 13 is directly incorporated (integrated) as at least part of the resonant components L2 and C2 of the RF power supply circuit 11 (without using a transmission line).

[0032] The RF power supply circuit 11, which is the plasma generation circuit 10, may include a first inductor (L1) 12a connected in series with the power supply (first power supply), and an electrically controlled switch 14, such as a MOSFET (power transistor, transistor switch), connected between the first inductor (L1) 12a and the primary common node 12b, the primary common node 12b being connected to either the second power supply or ground. The RF power supply circuit 11 further includes a first capacitor (C1) 18 connected in parallel with the electrically controlled switch 14 and between the first inductor (L1) 12a and the primary common node 12b, and a resonant circuit 16 connected in parallel with the electrically controlled switch 14. The resonant circuit 16 includes a plasma induction circuit 13 and a third capacitor (C3) 17 connected in series with it. The plasma induction circuit 13 is incorporated (integrated) as at least part of an inductor (second inductor, L2) 13a and / or a second capacitor (C2) 13b to directly form the resonant circuit 16. The RF power supply circuit 11 may further include a feedback circuit 15 for obtaining a feedback signal from an electrically controlled switch 14 from a feedback node 15a between the plasma induction circuit 13 and the third capacitor C3. The feedback circuit 15 may include a base resistor (Rbb) 15b. The RF power supply circuit 11 may also include a bias circuit for applying Vbias 19.

[0033] Figure 4 shows a typical self-regulating Class E power oscillator as a reference circuit for the RF power supply circuit 11 described above. Several types of Class E oscillators are described in US2020 / 0059198. The reference circuit 110 has a load (R LA load is required, and this load also needs impedance matching with other parts of the circuit. The plasma generation circuit 10 equipped with the RF power supply circuit 11 differs in that the inductor (L2) 13a and capacitor (C2) 13b of the plasma induction circuit 13 and the inductor (L2) 13a and capacitor (C2) 13b of the LC resonant circuit 16 are common or identical, and the inductor (L2) 13a and capacitor (C2) 13b are incorporated into the resonant circuit 16 as part of the resonant circuit 16. That is, the elements (elements) 13a and 13b of the plasma induction circuit 13 directly constitute the resonant circuit 16 (there are no transmission lines), and this load R L With the connection transmission lines eliminated, the electrical parameters of the plasma generation chamber 40 are determined by the characteristics (attributes, properties) of the RF power supply circuit 11 (plasma generation circuit 10).

[0034] Therefore, the need for impedance matching, transmission lines, and frequency references can be completely eliminated. The plasma generation circuit 10 continuously self-tunes itself as the load parameters change, automatically adapting to constantly changing load conditions, thus ensuring continuous and reliable operation of the circuit. Furthermore, since the plasma induction circuit 13 is built into the RF power supply circuit 11 without using transmission lines and an impedance matching mechanism is unnecessary, the configuration of the plasma generation circuit 10 is simplified, and the space required for installation of the plasma generation circuit 10 can be minimized. This also contributes to the miniaturization of the gas analyzer 1, enabling the provision of a modular, miniaturized, and / or portable gas analyzer 1.

[0035] The plasma induction circuit 13 may be configured by connecting a spiral planar inductor (L2) 13a and a capacitor (C2) 13b in series. A capacitor (C3) 17 (with a much larger value than capacitor C2) and a resistor Rb form a feedback circuit 15. These values ​​are calculated to ensure an appropriate phase shift of the self-starting oscillation mode for generating plasma 8 in the chamber 40.

[0036] The plasma induction circuit 13 is coupled (inductively and capacitively) to the plasma chamber 40, and as the parameters of the plasma chamber change continuously during normal operation, the effective parameters of the plasma induction circuit 13 also change. The feedback circuit 15 ensures a continuous oscillation mode by tracking the effective (coupled) parameters of the plasma induction circuit 13, significantly reducing the overall system sensitivity to variations in components, environment, and plasma chamber. The feedback can be obtained from node 15a between the plasma induction circuit 13 and capacitor (C3) 17, providing a signal amplitude high enough to supply for driving the electrically controlled switch 14. By incorporating the plasma induction circuit 13 as part of the actual LC parameters for setting the oscillation frequency of the RF power supply circuit 11, the oscillation frequency is autonomously determined by the effective LC parameters. This self-adjusting (self-regulating) design allows for stability against any variations in the mechanical properties of the chamber without the need for special impedance matching circuits.

[0037] As shown in the reference circuit (power oscillator, PO) 110 in Figure 4, the plasma induction circuit is under load R L If it is isolated from the resonant circuit, a cable (transmission line) is required, and it is usually a load R L The output of the PO110 has an impedance of 50Ω to connect to the plasma induction circuit installed in the plasma chamber 40. Cables (commercially available) have a parameter called "characteristic impedance," so the plasma induction circuit and the output of the PO110 (i.e., R) L The characteristic impedance of the ) must be exactly the same, that is, matched.

[0038] One of the major differences from the reference circuit 110 in Figure 4 is that the plasma generation circuit 10 of the present invention is for a plasma generator (integrated plasma generator), so the load R LThe fact that it is not used. Reference circuit 110 is a resonant circuit and R L Using R L This represents the load of the power oscillator, and the "load" can be anything that accepts the RF power generated by the oscillator. In the invention of the integrated plasma generator 10, the resonant circuit 16 is used as the load, i.e., R L It also functions as a load. Therefore, in our invention, the resonant circuit 16 is both a load and part of the plasma chamber 40. When the plasma chamber parameters change (which they do in actual applications), the parameters of the resonant circuit 16 also change, and the integrated plasma generator self-tunes itself, automatically maintaining optimal performance.

[0039] The term "impedance matching" originates from transmission line engineering, specifically the recognition of a "source" that generates RF power, a "load" that receives and dissipates this power, and a "transmission line" that connects these two and supplies power from the "source" to the "load." In this context, matching the physical parameters (such as RF impedance) of all these elements is crucial for the system to function properly.

[0040] In plasma generation, the impedance of the plasma chamber constantly changes with changes in conditions, causing a mismatch by altering the RF impedance of the "load." This can lead to many undesirable effects and even circuit failure. As described above, the plasma generation circuit 10 of this invention uses the resonant circuit 16 as the "load." That is, since the "load" is integrated into the "source," no "transmission line" is needed to connect the two. Also, for the same reason that the resonant circuit 16 is both the "load" and the "source," impedance matching of the transmission line is unnecessary, and since there is no concept of separate "source" and "load," impedance matching between them is also unnecessary. In this invention, there is only one circuit (integrated into the RF power supply circuit (power oscillator)), and when this circuit is properly designed and tested, it exhibits robust and efficient performance over a wide range of plasma chamber 40 parameters.

[0041] As described above, the present invention provides a compact gas analyzer 1 equipped with a plasma generation circuit 10. Since the plasma generation circuit 10 directly includes a plasma induction circuit 13, when the parameters of the plasma chamber change, the plasma generator (plasma generation circuit 10 having a plasma induction circuit 13) automatically self-tunes according to the parameters of the resonant circuit 16 built into the plasma generation circuit 10, maintaining optimal performance. One of the optimal applications of this gas analyzer 1 is process monitoring and control, as described above. The sample gas 9 to be measured is supplied from the process chamber 71 via a sampling device (sampler) 79, and the gas analyzer 1 analyzes the sample gas 9 via the generated plasma 8. The process controller 75 monitors and controls the process 72 according to the measurement results of the gas analyzer 1. The applications of this gas analyzer 1 are not limited to those described above, and taking advantage of its small size and portability, it can be used for a wide range of applications, such as environmental measurements at various sites and analysis of multiple gases in multiple (various) situations.

[0042] The foregoing description of specific embodiments is intended to fully illustrate the general nature of the embodiments herein, so that others may readily modify and / or adapt such specific embodiments for various uses without departing from the general concept by applying their current knowledge, and such adaptations and modifications should and are intended to be understood within the meaning and equivalents of the disclosed embodiments. It should be understood that any expressions or terms used herein are for illustrative purposes only and not to limit them. Thus, while the embodiments herein are described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein may be carried out with modifications within the spirit and scope of the appended claims.

Claims

1. A sample chamber into which the sample gas to be measured flows, A plasma generation circuit configured to generate plasma within the sample chamber, The analyzer is configured to analyze the sample gas via plasma generated in the sample chamber, The plasma generation circuit includes a plasma induction circuit that includes at least one of a plasma induction coil and a capacitor, A gas analyzer comprising an RF power supply circuit configured to supply RF power to the plasma induction circuit, wherein the plasma induction circuit is directly incorporated as at least a portion of the resonant components of the RF power supply circuit.

2. In claim 1, The RF power supply circuit is Electrically controlled switches, A first capacitor connected in parallel with the electrically controlled switch, A resonant circuit connected in parallel with the electrically controlled switch, the resonant circuit including the plasma induction circuit as at least part of an inductor and a second capacitor, and a third capacitor, A gas analyzer including a feedback circuit configured to obtain a feedback signal for an electrically controlled switch from a feedback node between the plasma induction circuit and the third capacitor.

3. In claim 1 or 2, A gas analyzer further having a base on which the sample chamber, the plasma generator, and the analyzer are assembled as a single module.

4. In claim 3, A gas analyzer further comprising an exhaust system configured to exhaust from the sample chamber, and assembled on a base on which the sample chamber, the plasma generator, and the analyzer are assembled as a single module.

5. In claim 1 or 2, An exhaust device configured to exhaust air from the sample chamber, A gas analyzer further comprising a base for integrating the sample chamber, the plasma generator, the analyzer, and the exhaust system as a single module.

6. In any of claims 1 to 5, A gas analyzer further comprising a first detector configured to detect ionized gas selected from plasma output from the sample chamber.

7. In any of claims 1 to 6, A gas analyzer further comprising a second detector configured to analyze the emission of ions in the plasma within the sample chamber.

8. A gas analyzer according to any one of claims 1 to 7, A system comprising a sampling device configured to supply the sample gas to be measured to the sample chamber.

9. In claim 8, A system comprising a process chamber from which plasma processing is performed, and further comprising a process chamber from which the sample gas is supplied to the gas analyzer.

10. In claim 8, A system further comprising a process monitoring device that monitors at least one process performed in the process chamber based on the measurement results of the gas analyzer.

11. In claim 8 or 9, A system further comprising a process control device that controls at least one process performed in the process chamber based on the measurement results of the gas analyzer.

12. Plasma generation chamber and It has a plasma generation circuit, The aforementioned plasma generation circuit is Electrically controlled switches, A first capacitor connected in parallel with the electrically controlled switch, A resonant circuit connected in parallel with the electrically controlled switch, comprising a plasma induction circuit and a third capacitor for generating plasma in the plasma generation chamber, wherein the plasma induction circuit is incorporated as at least part of an inductor and a second capacitor for directly forming the resonant circuit, A system including a feedback circuit for obtaining a feedback signal for the electrically controlled switch from a feedback node between the plasma induction circuit and the third capacitor.

13. In claim 12, A sampler configured to supply a sample gas to be measured to the plasma generation chamber, A system comprising an analyzer that analyzes the sample gas via the plasma generated in the plasma generation chamber.

14. In claim 13, The sampler is configured to supply the sample gas supplied from the process under monitoring, The system further comprises a process monitor for monitoring and controlling the process based on the measurement results of the analyzer.

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