Method and system for online detection of radical concentration

Abstract

The application provides a kind of radical concentration on-line detection method and detection system, detection method includes: control module executes first detection mode, to obtain background baseline signal;Control module executes second detection mode, to obtain total signal including the background baseline signal and radical concentration signal;Wherein, second detection mode is: open the power supply of plasma source and the ionizer, close the built-in ion source of gas analysis unit, and activate the ion capture and pulse extraction function of introducer, so that the radical ion produced by ionization of ionizer is captured in introducer and then is introduced into gas analysis unit for detection in pulse mode;Control module subtracts the total signal from the background baseline signal, to obtain the radical concentration signal.The detection method and detection system provided by the application can monitor the dynamic change of radical concentration in the process in real time, and improve the accuracy of detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor detection equipment, and particularly relates to a method and system for on-line detection of free radical concentration. BACKGROUND

[0002] In the etching and thin film process of semiconductor manufacturing, free radicals generated by plasma are widely relied on, and the high reactivity thereof can accurately etch or grow extremely thin structures of 5 nanometers or less. The free radical concentration directly determines the etching and thin film growth rate, but the short lifetime and neutral characteristics thereof make it difficult to be quantified. In actual production, plasma power drift, wear of grid assembly for filtering harmful ions, and fluctuation of process gas supply will all cause changes in free radical density, thereby causing instability in etching rate or growth rate, and seriously affecting wafer reproducibility and product quality.

[0003] Therefore, it is necessary to detect the free radical concentration in the etching and thin film process. The commonly used gas detection methods include spectroscopy and mass spectrometry. The sensitivity of this method for real-time detection of free radicals is insufficient, and there is a blind area in process monitoring, which affects the detection accuracy. SUMMARY

[0004] The present application relates to the technical field of semiconductor detection equipment, and particularly relates to a method and system for on-line detection of free radical concentration.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present application provides a method for on-line detection of free radical concentration, applied to semiconductor etching and thin film process, the detection method comprising:

[0006] The control module executes a first detection mode to obtain a background baseline signal; wherein the first detection mode is to turn off the ionizer, turn on the built-in ion source of the gas analysis unit, and turn off the ion capture and pulse extraction function of the introducer, so that the to-be-detected gas enters the gas analysis unit through the flow-limiting small hole of the introducer for ionization and detection;

[0007] The control module executes a second detection mode to obtain a total signal comprising the background baseline signal and a free radical concentration signal; wherein the second detection mode is to turn on the ionizer synchronously when the plasma source power of the semiconductor equipment is turned on, turn off the built-in ion source of the gas analysis unit, and activate the ion capture and pulse extraction function of the introducer, so that the free radical ions generated by the ionizer are captured in the introducer and then introduced into the gas analysis unit in a pulse manner for detection;

[0008] The control module subtracts the background baseline signal from the total signal to obtain the free radical concentration signal.

[0009] In some embodiments, the activating the ion trapping and pulsed extraction function of the introducer comprises:

[0010] starting a temperature controller in the introducer to cool an electrode layer in the introducer;

[0011] applying a radio frequency voltage and a decreasing direct current voltage to the electrode layer to form a potential field for trapping ions;

[0012] applying a high voltage pulsed voltage to the extraction electrode to accelerate and extract the trapped ions when the ion trapping stage is completed.

[0013] In some embodiments, the control module alternately executes the first detection mode and the second detection mode according to the power switch state of the plasma source, and the on time of the ionizer is synchronized with the on time of the power supply of the plasma source.

[0014] In some embodiments, the applying a radio frequency voltage and a decreasing direct current voltage to the electrode layer to form a potential field for trapping ions to achieve ion trapping comprises:

[0015] applying a radio frequency voltage of 50-300 Vpp and a decreasing direct current voltage of 0-200 V to the electrode layer; wherein the direct current voltage applied to the outermost layer of the electrode layer is U1, the direct current voltage applied to the innermost layer of the electrode layer is U2, and U1>U2;

[0016] applying a first direct current bias U3 to the extraction electrode, and U3>U2, to form a potential field for trapping ions on the electrode layer.

[0017] In some embodiments, the applying a high voltage pulsed voltage to the extraction electrode to accelerate and extract the trapped ions comprises:

[0018] applying a second direct current bias U3' to the extraction electrode, the second direct current bias U3' cooperating with the direct current voltage U2 applied to the innermost layer and the repelling electrode voltage U4 of the ion source in the gas analysis unit to form an axial acceleration electric field, the axial acceleration electric field being used to extract the trapped ions in the form of a pulsed packet;

[0019] wherein U4<U3'<U2.

[0020] In some embodiments, the turning on the ionizer comprises:

[0021] turning on a vacuum ultraviolet lamp in the ionizer and controlling the photon energy of the vacuum ultraviolet lamp to be 8 eV to 11.8 eV;

[0022] The photon energy generated by the vacuum ultraviolet lamp is transmitted into a transmission cavity; wherein the transmission cavity is used for transmitting plasma generated by the plasma source into a process cavity.

[0023] In a second aspect, the present application provides an online detection system for radical concentration, which can implement the online detection method, and the detection system comprises:

[0024] An ionizer is configured to selectively ionize specific radicals flowing through the transmission cavity; an introducer is connected to the transmission cavity and the gas analysis unit, and has ion capturing and pulse extraction functions; the gas analysis unit comprises an internal ion source, a mass analyzer, a detector and a vacuum system, and is configured to ionize and detect ions introduced by the introducer; and a control module is electrically connected to the ionizer, the introducer and the gas analysis unit, and can execute a first detection mode and a second detection mode.

[0025] In some embodiments, the introducer comprises a temperature controller, an insulating substrate, an electrode layer and an extraction electrode.

[0026] The insulating substrate is provided with a transmission channel.

[0027] The temperature controller is attached to one sidewall of the insulating substrate and is configured to adjust the temperature of the electrode layer.

[0028] The electrode layer comprises at least two concentric electrodes, which are arranged at another sidewall of the insulating substrate and are configured to capture ions.

[0029] The extraction electrode is arranged on the temperature controller and is close to the transmission channel, and is configured to transmit the captured ions on the electrode layer to the gas analysis unit through the transmission channel.

[0030] In some embodiments, the aperture of the transmission channel is between 0.02 mm and 0.2 mm.

[0031] In some embodiments, one end of the ion source is connected to the introducer and is configured to ionize the to-be-detected gas flowing through the introducer to form radical ions.

[0032] The mass analyzer is connected to another end of the ion source and is configured to separate the radical ions and transmit the radical ions to the detector for detection.

[0033] The vacuum system is configured to provide a vacuum environment for the mass analyzer.

[0034] The online detection method and the detection system for radical concentration have the following advantages:

[0035] 1. The application improves the sensitivity of free radical concentration detection by vacuum ultraviolet light soft ionization through an ionizer and dynamic ion capture and pulse introduction through an introduction device.

[0036] 2. The application realizes selective detection of specific free radicals by adjusting the energy and pulse timing of the ionizer and adjusting the dynamic ion capture and radio frequency voltage in the introduction device, effectively avoiding the interference of other components.

[0037] 3. The application synchronously controls the opening timing of the ionizer and the power supply of the plasma source, so that the response time of ionization, dynamic ion capture and pulse extraction operation is less than 100 milliseconds, realizing real-time online monitoring, so that the dynamic change of free radical concentration in the semiconductor process can be monitored in real time, providing data support for process control.

[0038] 4. The application can selectively use low-energy ionization to reduce fragment ions, combined with standard gas calibration to reduce detection error, thereby improving the accuracy of detection. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The flowchart of the online detection method of free radical concentration provided by the embodiment of the application;

[0040] Figure 2 The timing diagram of the cooperative work of each functional module of the detection system provided by the embodiment of the application;

[0041] Figure 3 The structural diagram of the detection system provided by the embodiment of the application;

[0042] Figure 4 The structural diagram of the gas analysis unit provided by the embodiment of the application;

[0043] Figure 5 The structural diagram of the introduction device provided by the embodiment of the application.

[0044] REFERENCE NUMERALS:

[0045] Process cavity 110, transmission cavity 120, plasma source 130, ionizer 210, introduction device 220, temperature controller 221, insulating substrate 222, electrode layer 223, extraction electrode 224, transmission channel 225, gas analysis unit 230, ion source 231, mass analyzer 232, detector 233, vacuum system 234, control module 240. DETAILED DESCRIPTION

[0046] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as their common meanings to those of ordinary skill in the art to which the present application belongs. The terms such as "comprise" and like terms used herein mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects.

[0047] The embodiments of the present application provide an online detection method of radical concentration, applied to semiconductor etching and thin film process, referring to Figure 1 and combining Figures 3 to 5 It is shown that the detection method comprises the steps of:

[0048] S101: The control module 240 executes a first detection mode to obtain a background baseline signal; wherein the first detection mode is that the ionizer 210 is turned off, the built-in ion source 231 of the gas analysis unit 230 is turned on, and the ion capture and pulse extraction function of the introducer 220 is turned off, so that the to-be-detected gas enters the gas analysis unit 230 through the flow-limiting small hole of the introducer 220 for ionization and detection.

[0049] It should be noted that the control module 240 has a first detection mode and a second detection mode, which alternately executes the first detection mode and the second detection mode according to the power switch state of the plasma source 130, and the opening time of the ionizer 210 is synchronized with the power-on time of the plasma source 130 of the semiconductor equipment. The plasma source 130 is used to provide plasma and transmit the plasma into the process cavity 110 through a transmission cavity. When the power of the plasma source 130 is turned off, the control module 240 executes the first detection mode, and when the power of the plasma source 130 is turned on, the control module 240 executes the second detection mode.

[0050] In this step, specifically, since the plasma source 130 is closed, the ionizer 210 is closed, and the ion capture and pulse introduction function of the introducer 220 is closed, at this time, only the un-ionized to-be-tested gas (such as SiH4, N2O, NH3, etc.) exists in the process cavity 110, the to-be-tested gas enters the gas analysis unit 230 through the flow-limiting small hole of the introducer 220, and since the built-in ion source 231 of the gas analysis unit 230 is turned on, the to-be-tested gas is ionized to generate a fragment ion spectrum. The gas analysis unit 230 detects the fragment ion spectrum to obtain a background baseline signal.

[0051] S102: The control module 240 executes a second detection mode to obtain a total signal including the background baseline signal and a free radical concentration signal; wherein the second detection mode is: turning on the power supply of the plasma source 130 and the ionizer 210, turning off the built-in ion source 231 of the gas analysis unit 230, and activating the ion capture and pulse introduction function of the introducer 220, so that the free radical ions generated by the ionizer 210 are captured in the introducer 220 and then introduced into the gas analysis unit 230 in a pulse manner for detection.

[0052] In this step, the power supply of the plasma source 130 and the ionizer 210 are turned on, and at this time, the plasma source 130 releases plasma into the process cavity 110 through the transmission cavity. During this process, since the energy required for ionization of different plasmas is different, the embodiment controls the vacuum ultraviolet lamp in the ionizer 210 to release photon energy in the range of 8eV to 11.8eV, so as to selectively ionize the plasma according to actual needs to generate free radical ions and avoid matrix interference.

[0053] Further, the ion capture and pulse introduction function of the introducer 220 specifically includes the following steps:

[0054] The temperature controller 221 in the introducer 220 is started to cool the electrode layer 223 in the introducer 220. For example, the cooling temperature is controlled at -20℃ to -40℃.

[0055] The radio frequency voltage and the decreasing direct current voltage are applied to the electrode layer 223 to form a potential field for capturing ions. That is, the free radical ions are captured on the ice-cold electrode layer 223.

[0056] Specifically, in this step, a radio frequency voltage of 50-300Vpp is applied to the electrode layer 223, and a direct current voltage of 0-200V is applied in a decreasing manner; the direct current voltage applied to the outermost layer of the electrode layer 223 is U1, the direct current voltage applied to the innermost layer of the electrode layer 223 is U2, and U1>U2; a first direct current bias U3 is applied to the extraction electrode 224, and U3>U2, so as to form a potential field of the captured ions on the electrode layer 223.

[0057] When the ion capturing stage ends, the temperature controller 221 is started to heat the electrode layer 223, and a high-voltage pulse voltage is applied to the extraction electrode 224, so as to accelerate and extract the captured ions.

[0058] Specifically, in this step, a second direct current bias U3' is applied to the extraction electrode 224, the second direct current bias U3' cooperates with the direct current voltage U2 applied to the innermost layer and the repelling electrode voltage U4 of the ion source 231 in the gas analysis unit 230 to form an axial acceleration electric field, and the axial acceleration electric field is used to extract the captured ions in the form of pulse packets.

[0059] Wherein, U4<U3'<U2.

[0060] S103: The control module 240 subtracts the total signal from the background baseline signal to obtain the free radical concentration signal.

[0061] In this embodiment, the control module 240 controls the ionizer 210, the electrode layer 223, the extraction electrode 224, the ion source 231 and other modules in the gas analysis unit 230 to periodically and alternately perform (each cycle is several hundred milliseconds to several seconds) the detection method provided in the above embodiment, so as to realize real-time monitoring of the dynamic change of the free radical concentration in the semiconductor process, and provide data support for process control. Figure 2 As shown in FIG. 1, the control module 240 controls the ionizer 210, the electrode layer 223, the extraction electrode 224, the ion source 231 and other modules in the gas analysis unit 230 to periodically and alternately perform (each cycle is several hundred milliseconds to several seconds) the detection method provided in the above embodiment, so as to realize real-time monitoring of the dynamic change of the free radical concentration in the semiconductor process, and provide data support for process control. Moreover, the ionization by the ionizer 210 and the dynamic ion capture by the extraction electrode 224 greatly improve the sensitivity of the detection of the free radical concentration. In addition, the energy and pulse timing of the ionizer 210 and the dynamic ion capture and radio frequency voltage of the extraction electrode 224 can be adjusted to realize selective detection of specific free radicals, effectively avoid the interference of other components, and improve the accuracy of the detection data.

[0062] In another embodiment provided in the present application, an online detection system of a free radical concentration is provided, which is used to be installed on a plasma chemical vapor deposition system (PECVD), and can implement the detection method provided in the above embodiment on the PECVD.

[0063] Reference is made to Figure 3 andFigure 4 As shown, in a plasma chemical vapor deposition system (PECVD), a plasma source 130 is connected with a process chamber 110 through a transmission chamber 120, the plasma source 130 is used to provide plasma, and the transmission chamber 120 is used to transmit the plasma into the process chamber 110 for chemical vapor deposition. The detection system includes an ionizer 210, an introducer 220, a gas analysis unit 230, and a control module 240. The ionizer 210 is installed on the sidewall of the transmission chamber 120, and is used to selectively ionize specific radicals flowing through the transmission chamber 120 by controlling the ionization energy, so as to form radical ions. The introducer 220 is connected with the transmission chamber 120 and the gas analysis unit 230, and has the functions of ion capture and pulse extraction. The to-be-detected gas or radical ions in the transmission chamber 120 can enter the gas analysis unit 230 through the introducer 220. The gas analysis unit 230 includes an internal ion source 231, a mass analyzer 232, a detector 233, and a vacuum system 234. The mass analyzer 232 is used to connect the detector 233 with the ion source 231. The ion source 231 is used to ionize the ions introduced by the introducer 220. The detector 233 is used to detect the radical ions formed after ionization. The vacuum system 234 provides a vacuum environment for the gas analysis unit 230. The control module 240 is electrically connected with the ionizer 210, the introducer 220, and the gas analysis unit 230, and can execute a first detection mode and a second detection mode.

[0064] In the embodiment, the detection system can monitor the dynamic change of the radical concentration in the semiconductor process in real time, and provide data support for process control. The ionization by the ionizer 210 and the dynamic ion capture and pulse extraction by the introducer 220 greatly improve the sensitivity of the radical concentration detection. In addition, the selective detection of specific radicals can be realized by adjusting the energy and pulse timing of the ionizer 210 and adjusting the dynamic ion capture and radio frequency voltage in the introducer 220, the interference of other components is effectively avoided, and the accuracy of the detection data is improved.

[0065] Reference Figure 3 and Figure 5As shown, in some embodiments, the introducer 220 includes a temperature controller 221, an insulating substrate 222, an electrode layer 223, and an extraction electrode 224. The insulating substrate 222 has a transmission channel 225 formed therein, which connects the insulating substrate 222. The temperature controller 221 is attached to one side wall of the insulating substrate 222, and is used to adjust the temperature of the electrode layer 223. The electrode layer 223 includes at least two concentric electrodes, which are arranged at a distance from each other on the other side wall of the insulating substrate 222, and are used to capture ions. The extraction electrode 224 is arranged on the temperature controller 221 and is close to the transmission channel 225, and is used to transmit the captured ions on the electrode layer 223 to the gas analysis unit 230 through the transmission channel 225.

[0066] In this embodiment, the temperature controller 221 is a thermoelectric cooler, which is tightly coupled to the back of the insulating substrate 222 through a thermal interface material (such as a heat-conductive epoxy resin). The temperature controller 221 can accurately cool or heat, and transmit the required temperature to the electrode layer 223 through the insulating substrate 222. The insulating substrate 222 is a high-thermal-conductivity insulating substrate 222, which can be made of ceramic, metalized PCB material, or aluminum nitride material.

[0067] When the control module 240 controls the introducer 220 to perform the ion capture function, the temperature controller 221 reduces the temperature of the electrode layer 223, and applies a radio frequency voltage and a decreasing direct current voltage to the electrode layer 223 to form a potential field for capturing ions, thereby achieving the ion capture function and capturing the free radical ions in the transmission cavity 120.

[0068] When the ion capture stage is completed, the control module 240 controls the introducer 220 to start the pulse extraction function. At this time, the temperature controller 221 needs to be started to heat the electrode layer 223, and a high-voltage pulse voltage is applied to the extraction electrode 224, so as to accelerate and extract the ions captured on the electrode layer 223 through the transmission channel 225.

[0069] It can be understood that, by using the introducer 220 in this embodiment, a two-dimensional, nearly uniform radio frequency electric field "blanket" is created at the connection with the transmission cavity 120. This electric field can efficiently confine the ions generated by soft ionization of a vacuum ultraviolet lamp (VUV) in a quasi-two-dimensional plane, and by dynamically controlling the parameters of the electric field, the ions can be captured, cooled, and "kicked" into the subsequent gas analysis unit 230 in a pulsed manner. This technology solves the problems of unstable ion flow, low transmission efficiency, and poor signal-to-noise ratio caused by the existing sampling method, and is particularly suitable for detection of low-concentration, transient free radicals in a process.

[0070] In some embodiments, the transmission channel 225 has an aperture between 0.02 mm and 0.2 mm.

[0071] In some embodiments, the transmission channel 225 has an aperture of 0.03 mm, 0.05 mm, 0.07 mm, 0.09 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.17 mm, or 0.19 mm.

[0072] In some embodiments, the ion source 231 is in communication with one end of the inlet 220 for ionizing the gas flowing through the inlet 220 to form radical ions. The mass analyzer 232 is in communication with the other end of the ion source 231 for separating and screening the radical ions and transmitting the radical ions to the detector 233 for detection. The vacuum system 234 is connected to the mass analyzer 232 for providing a vacuum environment for the mass analyzer 232.

[0073] In the present embodiment, the mass analyzer 232 can be a quadrupole mass spectrometer, an ion trap mass spectrometer, a quadrupole array mass spectrometer, or other instruments that can achieve the function. The detector 233 can be a Faraday cup, an electron multiplier, or a combination of the two. The vacuum system 234 can be a combination of a mechanical pump and a molecular pump to provide a high vacuum environment for the mass analyzer 232, which can maintain a vacuum pressure of 10 -5 to 10 -7 Torr.

[0074] In some embodiments, the ionizer 210 includes a vacuum ultraviolet lamp corresponding to the observation window on the transmission cavity 120, and a lamp cover covering the outside of the vacuum ultraviolet lamp. The photon energy of the vacuum ultraviolet lamp is adjustable in the range of 8 eV to 11.8 eV, the material of the observation window is consistent with the material of the lamp cover, and the control unit controls the vacuum ultraviolet lamp to pulse ionize specific radicals.

[0075] Although the embodiments of the present application have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to the embodiments. However, it should be understood that such modifications and changes are within the scope and spirit of the present application. Moreover, the present application described herein can have other embodiments and can be implemented or realized in various ways.

Claims

1. An online method for detecting free radical concentration, applied to semiconductor etching and thin film processes, characterized in that, The detection method includes: The control module executes the first detection mode to obtain the baseline signal; wherein, the first detection mode is: turning off the ionizer, turning on the built-in ion source of the gas analysis unit, and turning off the ion capture and pulse extraction functions of the introducer, so that the gas to be tested enters the gas analysis unit through the flow-limiting orifice of the introducer for ionization and detection; The control module executes a second detection mode to obtain a total signal including the background baseline signal and the free radical concentration signal; wherein, the second detection mode is: when the plasma source power supply of the semiconductor device is turned on, the ionizer is turned on simultaneously, the built-in ion source of the gas analysis unit is turned off, and the ion capture and pulse extraction function of the introducer is activated, so that the free radical ions generated by the ionizer are captured in the introducer and then pulsedly introduced into the gas analysis unit for detection; The control module subtracts the total signal from the background baseline signal to obtain the free radical concentration signal; The ion trapping and pulse extraction function of the introducer is activated, including: The temperature controller in the introducer is activated to cool the electrode layer in the introducer; A radio frequency voltage and a decreasing DC voltage are applied to the electrode layer to form a potential field for capturing ions, thereby achieving ion capture; After the ion capture stage is completed, the temperature controller is activated to heat the electrode layer and a high-voltage pulse voltage is applied to the extraction electrode to accelerate the extraction of captured ions. Applying a radio frequency voltage and a decreasing DC voltage to the electrode layer to form a potential field for trapping ions includes: A radio frequency voltage of 50-300 Vpp and a DC voltage of 0-200V in a decreasing manner are applied to the electrode layer; wherein, the DC voltage applied to the outermost layer of the electrode layer is U1, the DC voltage applied to the innermost layer is U2, and U1>U2; A first DC bias voltage U3 is applied to the lead-out electrode, where U3 > U2, to form a potential field for capturing ions on the electrode layer.

2. The online detection method according to claim 1, characterized in that, The control module alternately executes the first detection mode and the second detection mode according to the power switch status of the plasma source, and the turn-on time of the ionizer is synchronized with the power-on time of the plasma source.

3. The online detection method according to claim 1, characterized in that, Applying a high-voltage pulse to the extraction electrode to accelerate the extraction of trapped ions includes: A second DC bias voltage U3' is applied to the extraction electrode. The second DC bias voltage U3', together with the DC voltage U2 applied to the innermost layer and the repulsion voltage U4 of the ion source in the gas analysis unit, form an axial accelerating electric field. The axial accelerating electric field is used to extract the captured ions in the form of pulse packets. Among them, U4 <U3’<U2。 4. The online detection method according to claim 1, characterized in that, Turning on the ionizer includes: Turn on the vacuum ultraviolet lamp in the ionizer and control the photon energy of the vacuum ultraviolet lamp between 8 eV and 11.8 eV; The photon energy generated by the vacuum ultraviolet lamp is transferred to the transmission cavity; wherein, the transmission cavity is used to transfer the plasma generated by the plasma source to the process cavity.

5. An online detection system for free radical concentration, characterized in that, The online detection method according to any one of claims 1 to 4 can be implemented, wherein the detection system comprises: An ionizer is used to selectively ionize specific free radicals flowing through the transmission cavity; an introducer is connected to the transmission cavity and the gas analysis unit, and the introducer has ion capture and pulse extraction functions; the gas analysis unit includes a built-in ion source, mass analyzer, detector and vacuum system, and is used to ionize and detect ions introduced by the introducer; a control module is electrically connected to the ionizer, the introducer and the gas analysis unit, and the control module can execute a first detection mode and a second detection mode.

6. The online detection system according to claim 5, characterized in that, The inlet device includes a temperature controller, an insulating substrate, an electrode layer, and an outlet electrode; A transmission channel is formed on the insulating substrate; The temperature controller is attached to one side wall of the insulating substrate and is used to adjust the temperature of the electrode layer; The electrode layer includes at least two concentric electrodes, which are spaced apart and disposed on the other sidewall of the insulating substrate for capturing ions; The lead-out electrode is located on the temperature controller and close to the transmission channel, and is used to transmit the ions captured on the electrode layer to the gas analysis unit through the transmission channel.

7. The online detection system according to claim 6, characterized in that, The aperture of the transmission channel is between 0.02 mm and 0.2 mm.

8. The online detection system according to claim 5, characterized in that, One end of the ion source is connected to the introducer and is used to ionize the gas to be tested flowing through the introducer to form free radical ions; The mass analyzer is connected to the other end of the ion source and is used to separate the free radical ions and transmit the free radical ions to the detector for detection; The vacuum system is used to provide a vacuum environment for the mass analyzer.

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