Multi-path residual gas analysis cooperative detection system based on single ion source

Abstract

The invention discloses a multi-path residual gas analysis and collaborative detection system based on a single ion source. The multi-path residual gas analysis and collaborative detection system mainly comprises an ion source assembly, a quadrupole rod mass analyzer, a detection system and a control and data fusion module, the ion source assembly comprises a filament module and two transmission lenses, residual gas is ionized into ions by the filament module, the ions flow into the quadrupole rod mass analyzer through the transmission lenses and are screened, and ions with specific mass flow into the detection system from the quadrupole rod mass analyzer and are converted into digital signals to be transmitted to the control and data fusion module; the control and data fusion module fuses digital signals of the two detection systems into a single spectrogram. According to the invention, through a combined RGA design, comprehensive application and linkage of multiple process scenes are realized; simultaneous scanning in positive and negative ion modes can be realized, and acquired data information is richer; when full-spectrum information is scanned, sectional scanning can be realized, and the scanning speed is at least doubled.

Description

Technical Field

[0001] This invention relates to the field of vacuum mass spectrometry detection and semiconductor manufacturing process monitoring technology, and in particular to a multi-channel residual gas analysis and collaborative detection system based on a single ion source. Background Technology

[0002] As semiconductor manufacturing processes evolve towards smaller nodes (7nm, 5nm, 3nm, EUV processes), the process window is narrowing, and trace gases, contaminants, and leaks in the vacuum environment significantly impact yield. Residual gas analyzers (RGAs), as mass spectrometry-based analytical devices, are crucial tools for monitoring vacuum quality in semiconductor equipment. However, existing RGAs primarily employ a "single ion source + single mass spectrometry channel" approach, which has the following shortcomings: (1) It cannot support multiple detection modes at the same time. When switching between positive ion mode and negative ion mode, RGA needs to change the ionization polarity, which has a settling time and cannot achieve real-time synchronous monitoring.

[0003] (2) The limited quality range makes it impossible to balance high-speed and wide-spectrum scanning. Full-spectrum scanning (e.g., 1–300 amu) is slow and not suitable for the fast transient processes in ALD and etching; while high-speed scanning is usually limited to a small range below 50 amu, which cannot meet the needs of wide-span quality monitoring.

[0004] (3) A single RGA is difficult to achieve parallel monitoring for different purposes. In some application scenarios, in order to more accurately determine the gas change state in the chamber, it is necessary to monitor the full spectrum information at the same time as monitoring the specific ions of interest; a single RGA cannot achieve parallel monitoring. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a multi-channel residual gas analysis and collaborative detection system based on a single ion source. It innovatively designs an ion source that can only connect to one mass analyzer in the traditional way, allowing the ion source to connect to multiple mass analyzers simultaneously. The multiple mass analyzers are each set to a different scanning mode, and the data from all mass analyzers are fused into a single spectrum, thereby obtaining more comprehensive scanning data and improving scanning speed.

[0006] The technical solution of the present invention is as follows: A multi-channel residual gas analysis and collaborative detection system based on a single ion source includes a vacuum sampling interface 1, an ion source assembly 2, a mass analyzer 3, a detection system 4, an electronic control module 5, and a control and data fusion module 6; the combination of the mass analyzer 3, the detection system 4, and the electronic control module 5 is referred to as an RGA, and the number of RGAs is not less than 2; The residual gas to be detected flows into the ion source assembly 2 through the vacuum sampling interface 1. The ion source assembly 2 includes a filament module 7 and a transmission lens 8, the number of which is equal to the number of RGAs. The filament module 7 is heated to a high temperature and generates a large number of free electrons, ionizing the residual gas into charged ions. The transmission lens 8 has a coaxial three-electrode axisymmetric structure. Under the action of the transmission lens 8, the charged ions form a parallel and coaxial ion beam and flow into the mass analyzer 3. Under the action of the electrostatic field of the mass analyzer 3, some of the charged ions collide with the electrode rod of the mass analyzer 3, and the remaining charged ions flow into the detection system. System 4; Detection system 4 converts the received charged ions into a current signal, then converts it into a digital signal via ADC, preprocesses the digital signal, and combines the preprocessed digital signal with the detection time to obtain RGA data. Finally, the RGA data is sent to control and data fusion module 6; Control and data fusion module 6 receives all RGA data and fuses all RGAs into a single spectrum according to the detection time; The electronic control module 5 is connected to ion source component 2 and mass analyzer 3 and is used to adjust the operating parameters of ion source component 2 and mass analyzer 3; The operating parameters include voltage, current, and frequency.

[0007] Furthermore, the quality analyzer 3 is a quadrupole quality analyzer.

[0008] Furthermore, the ion source component 2 is cylindrical or cubic in shape.

[0009] Furthermore, the preprocessing of the detection system 4 includes noise reduction, peak detection, and mass axis calibration.

[0010] Furthermore, the operating modes of the multi-channel residual gas analysis and collaborative detection system include: (1-1) Different RGAs simultaneously scan different quality segments and transmit the acquired RGA data to the control and data fusion module 6; the control and data fusion module 6 stitches the RGA data of different quality segments into a single spectrum, then performs quality axis calibration and relative intensity normalization, and presents it in real time; (1-2) Different RGAs simultaneously scan different ion polarities. The positive ion mode performs a full scan / skip scan of standard spectrum data, while the negative ion mode is used to monitor halogen reactants. The two ion modes are scanned and monitored simultaneously, and the data obtained from the two ion modes are integrated and displayed in real time through the control and data fusion module 6. (1-3) Different RGAs execute different scanning modes. One RGA performs a full-spectrum scan to record complete spectral information, obtain trend changes and abnormal peaks, while another RGA locks onto the target ion for high-speed sampling to achieve a rapid response. (1-4) All RGAs perform the same scan mode. RGA data from different sources are used for cross-validation to improve data reliability. At the same time, when any RGA drifts or fails, another RGA automatically takes over the scan task.

[0011] Furthermore, the control and data fusion module 6 runs on a real-time operating system or an FPGA+CPU hybrid architecture and performs the following operations: (2-1) Calibrate and calibrate the mass axis of RGA data from different sources; (2-2) Assign different proportional weights to RGA data from different sources and then merge them into a single spectrum; (2-3) Perform the following preprocessing on the RGA data: real-time denoising, baseline correction, and drift compensation to obtain preprocessed RGA data; (2-4) Based on the preprocessed RGA data obtained in (2-3), perform closed-loop control, that is: if an RGA detects a sharp increase in the target ion concentration, adjust the voltage of the ion source component 2 to encourage more ion flow to enter another RGA, thereby obtaining a higher signal-to-noise ratio.

[0012] Furthermore, when different RGAs simultaneously scan different quality segments, the control and data fusion module 6 assigns different proportional weights to the data of different RGAs, and merges and restores the spectrum through proportional weights.

[0013] Furthermore, the number of both the RGA and the transmission lens 8 is 2; The ion source assembly 2 is cylindrical in shape, the filament module 7 is disposed inside the cylinder, and the transmission lens 8 is disposed on the plane of the cylinder; along the central axis of the ion source assembly 2, the arrangement order of the filament module 7 and the transmission lens 8 is: transmission lens 8, filament module 7, transmission lens 8.

[0014] The beneficial technical effects of this invention are as follows: (1) This invention realizes the comprehensive application and linkage of RGA equipment in multiple process scenarios through a combined RGA design; (2) Commonly used RGA only supports positive ion mode scanning. This invention not only supports negative ion scanning, but also can achieve simultaneous scanning of positive and negative ion modes, and obtain richer data information. (3) When scanning full-spectrum information (e.g., 1-300 amu), RGA is usually limited by the scanning speed and cannot capture real-time gas information in the chamber instantaneously in scenarios with rapid gas changes. The present invention enables segmented scanning, which at least doubles the scanning speed.

[0015] (4) The present invention realizes that in some specific application scenarios, RGA needs to monitor the full spectrum information at the same time while monitoring specific target ions. Attached Figure Description

[0016] Figure 1 This is an overall structural diagram of the embodiment; Figure 2 This is a mechanical structure diagram of the ion source assembly.

[0017] In the figure, the correspondence between the component names and the attached drawing numbers is as follows: 1. Vacuum sampling interface; 2. Bidirectional ion source assembly; 3. Mass analyzer; 4. Detection system; 5. Electrical control module; 6. Control and data fusion module; 7. Filament module; 8. Transmission lens. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] The design concept of this embodiment is to innovate the traditional ion source that can only connect to one mass analyzer by using a filament module 7 with multiple transmission lenses 8, so that the ion source can connect to multiple mass analyzers at the same time. On this basis, a control and data fusion module 6 was independently developed to set the multiple mass analyzers to different scanning modes and fuse the data of all mass analyzers into a single spectrum, thereby not only obtaining more comprehensive scanning data, but also improving the scanning speed.

[0020] I. Structure like Figure 1 As shown, the embodiment mainly includes a vacuum sampling interface 1, an ion source assembly 2, a quadrupole mass analyzer 3, a detection system 4, an electronic control module 5, and a control and data fusion module 6. The combination of the quadrupole mass analyzer 3, the detection system 4, and the electronic control module 5 is referred to as an RGA. There are two RGAs, designated RGA-1 and RGA-2 respectively.

[0021] The residual gas to be detected flows into the ion source assembly 2 through vacuum sampling interface 1. The mechanical structure of the ion source assembly 2 is as follows: Figure 2 As shown, the ion source assembly 2 mainly includes a filament module 7 and two transmission lenses 8. The ion source assembly 2 is cylindrical in shape, with the filament module 7 disposed inside the cylinder and the transmission lenses 8 disposed on the plane of the cylinder. Along the central axis of the ion source assembly 2, the arrangement order of the filament module 7 and the transmission lenses 8 is: transmission lens 8, filament module 7, transmission lens 8.

[0022] After the filament module 7 is heated to a high temperature, it generates a large number of free electrons, which ionize the residual gas into charged ions. The transmission lens 8 has a coaxial three-electrode axisymmetric structure. Under the action of the transmission lens 8, the charged ions form a parallel and coaxial ion beam and flow into the quadrupole mass analyzer 3. Under the action of the electrostatic field of the mass analyzer 3, some of the charged ions collide with the poles of the quadrupole mass analyzer 3, and the remaining charged ions flow into the detection system 4. The detection system 4 converts the received charged ions into a current signal, and then converts it into a digital signal through an ADC. Then, it performs preprocessing such as noise reduction, peak detection, and mass axis calibration on the digital signal. The preprocessed digital signal is combined with the detection time to obtain RGA data. Finally, the RGA data is sent to the control and data fusion module 6. The control and data fusion module 6 receives all RGA data and fuses all RGAs into a single spectrum according to the detection time. The electronic control module 5 is connected to the ion source assembly 2 and the mass analyzer 3 and is used to adjust the operating parameters such as voltage, current and frequency of the ion source assembly 2 and the mass analyzer 3.

[0023] II. Driver Drive and control of ion source component 2 (1) Filament emission drive: constant current drive circuit with soft start function and temperature protection; filament switching is automatically switched by the electronic control module 5 when current drift or breakage is detected; (2) Electron energy setting: The electron acceleration voltage is provided by a high-voltage source and can be adjusted in the range of 30–70 V; it is used to control the ionization energy and directly affects the ionization efficiency. (3) Positive / negative ion switching: By switching the voltage, the polarity of the ionization region field is changed. In parallel mode, constant polarity can be used and ions under different conditions can be guided to different RGAs respectively.

[0024] 2. RGA Scan Driver and Detection (1) Quadrupole quality analyzer 3 drive: Each RGA is equipped with an independent RF / DC voltage drive source, and the frequency and amplitude can be adjusted by the program.

[0025] (2) Detection system 4 preamplifier: low noise transimpedance amplifier for Faraday cup / SEM output with automatic gain control to avoid overload while maintaining high sensitivity to weak signals.

[0026] (3) ADC and real-time processing: Each RGA performs preprocessing such as noise reduction, peak detection and mass axis calibration through local FPGA algorithm; then the processed mass spectrometry data packet is sent to the control and data fusion module 6 through a dedicated bus.

[0027] 3. Data fusion and control algorithms Control and data fusion module 6 runs on a real-time operating system or an FPGA+CPU hybrid architecture and is responsible for: (1) Alignment of each RGA mass axis (time and mass calibration); The mass axis is the horizontal axis that displays the mass spectrum. Sometimes the mass axis may be offset, so it is necessary to calibrate the mass axis, which means calibrating and aligning the mass axes of each RGA channel. (2) Merge data from different RGAs according to their weights (e.g., give high weight to RGA-1 for high quality segments and high weight to RGA-2 for low quality segments); when each RGA is scanned by quality segment, each RGA introduces ions of different proportions through different lens voltages. When the RGAs are finally merged into a single spectrum, the spectrum is restored by merging the proportions and weights. (3) Real-time noise reduction, baseline correction, drift compensation (temperature drift, filament aging effect), and feedback to the driving layer for adaptive gain or polarity adjustment.

[0028] (4) The driving layer provides closed-loop control: If RGA-1 detects a sharp increase in the target ion concentration, the ion source voltage can be adjusted to allow more ion flow to enter RGA-2 to obtain a higher signal-to-noise ratio.

[0029] III. Work Process The embodiment connects to a semiconductor process equipment; the semiconductor process equipment sends an external trigger signal; the electronic control module 5 receives the trigger signal and begins synchronization timing, issuing instructions to RGA-1 and RGA-2 to begin execution; the parameters of the ion source components 2 of the two RGAs are set according to preset parameter values, with electron energy and emission current set according to the process mode (e.g., 70 eV, filament current 2 mA); depending on the application scenario, each RGA synchronously and in parallel executes a specific scan and performs local preprocessing, while each RGA individually performs baseline subtraction and peak detection and sends data packets to the data fusion module. The system can be configured with multiple operating modes according to actual usage scenario requirements: 1. RGA performs scans in different quality segments: RGA-1 scans the 1-50 amu quality segment; RGA-2 scans the 51-100 amu quality segment. The two RGAs are scanned and acquired synchronously. The data is output to the data fusion module to stitch the different quality segments into a single spectrum, perform quality axis calibration and relative intensity normalization, and present the data in real time.

[0030] 2. RGA performs scans of different ion polarities: positive ion mode performs full scan / skip scan of standard spectral data; negative ion mode is used to monitor halogen reactants. Both ion modes are scanned and monitored simultaneously, and the data obtained from the two ion modes are integrated and displayed in real time through the data fusion module.

[0031] 3. RGA performs different scanning modes: RGA-1 performs a full-spectrum scan to record complete spectral information, obtain trend changes and abnormal peaks, while RGA-2 locks onto the target ion and performs high-speed sampling to achieve a rapid response.

[0032] The RGAs execute the exact same scanning mode: based on the monitoring requirements of the application scenario, two sets of RGAs simultaneously scan a process segment using the same scanning mode and scanning quality range, serving as cross-validation to improve data reliability. Furthermore, if any one RGA experiences drift or failure, the other automatically takes over the scanning task.

[0033] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, and for those of ordinary skill in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. Therefore, the present invention is not limited to the specific details without departing from the general concept defined by the claims and their equivalents.

Claims

1. A multi-channel residual gas analysis and collaborative detection system based on a single ion source, characterized in that: It includes a vacuum sampling interface (1), an ion source assembly (2), a mass analyzer (3), a detection system (4), an electrical control module (5), and a control and data fusion module (6); the combination of the mass analyzer (3), the detection system (4), and the electrical control module (5) is called an RGA, and the number of RGAs is not less than 2; The residual gas to be detected flows into the ion source assembly (2) through the vacuum sampling interface (1); the ion source assembly (2) includes a filament module (7) and a transmission lens (8), the number of transmission lenses (8) being equal to the number of RGAs; the filament module (7) generates a large number of free electrons after being heated to a high temperature, ionizing the residual gas into charged ions; the transmission lens (8) is a coaxial three-electrode axisymmetric structure, and the charged ions form a parallel and coaxial ion beam under the action of the transmission lens (8), and flow into the mass analyzer (3); under the action of the electrostatic field of the mass analyzer (3), some of the charged ions collide with the electrode rod of the mass analyzer (3), and the remaining charged ions flow into The detection system (4) converts the received charged ions into a current signal, then converts it into a digital signal via an ADC, preprocesses the digital signal, and combines the preprocessed digital signal with the detection time to obtain RGA data. Finally, the RGA data is sent to the control and data fusion module (6). The control and data fusion module (6) receives all RGA data and fuses all RGAs into a single spectrum according to the detection time. The electronic control module (5) is connected to the ion source component (2) and the mass analyzer (3) and is used to adjust the operating parameters of the ion source component (2) and the mass analyzer (3). The operating parameters include voltage, current and frequency.

2. The multi-channel residual gas analysis and collaborative detection system based on a single ion source according to claim 1, characterized in that, The mass analyzer (3) is a quadrupole mass analyzer.

3. The multi-channel residual gas analysis and collaborative detection system based on a single ion source according to claim 1, characterized in that, The ion source component (2) is cylindrical or cubic in shape.

4. The multi-channel residual gas analysis and collaborative detection system based on a single ion source according to claim 1, characterized in that, The preprocessing of the detection system (4) includes noise reduction, peak detection, and mass axis calibration.

5. The multi-channel residual gas analysis and collaborative detection system based on a single ion source according to claim 1, characterized in that: The operating modes of the multi-channel residual gas analysis and collaborative detection system include: (1-1) Different RGAs simultaneously scan different quality segments and transmit the acquired RGA data to the control and data fusion module (6); the control and data fusion module (6) stitches the RGA data of different quality segments into a single spectrum, then performs quality axis calibration and relative intensity normalization, and presents it in real time; (1-2) Different RGAs simultaneously scan different ion polarities. The positive ion mode performs a full scan / skip scan of standard spectrum data, while the negative ion mode is used to monitor halogen reactants. The two ion modes are scanned and monitored simultaneously, and the data obtained from the two ion modes are integrated and displayed in real time through the control and data fusion module (6). (1-3) Different RGAs execute different scanning modes. One RGA performs a full-spectrum scan to record complete spectral information, obtain trend changes and abnormal peaks, while another RGA locks onto the target ion for high-speed sampling to achieve a rapid response. (1-4) All RGAs perform the same scan mode. RGA data from different sources are used for cross-validation to improve data reliability. At the same time, when any RGA drifts or fails, another RGA automatically takes over the scan task.

6. The multi-channel residual gas analysis and collaborative detection system based on a single ion source according to claim 5, characterized in that: The control and data fusion module (6) runs on a real-time operating system or an FPGA+CPU hybrid architecture and performs the following operations: (2-1) Calibrate and calibrate the mass axis of RGA data from different sources; (2-2) Assign different proportional weights to RGA data from different sources and then merge them into a single spectrum; (2-3) Perform the following preprocessing on the RGA data: real-time denoising, baseline correction, and drift compensation to obtain preprocessed RGA data; (2-4) Based on the preprocessed RGA data obtained in (2-3), perform closed-loop control, that is: if an RGA detects a sharp increase in the target ion concentration, adjust the voltage of the ion source component (2) to encourage more ion flow to enter another RGA, thereby obtaining a higher signal-to-noise ratio.

7. The multi-channel residual gas analysis and collaborative detection system based on a single ion source according to claim 5, characterized in that: When different RGAs scan different quality segments simultaneously, the control and data fusion module (6) assigns different proportional weights to the data of different RGAs and merges and restores the spectrum through proportional weights.

8. The multi-channel residual gas analysis and collaborative detection system based on a single ion source according to claim 3, characterized in that: The number of RGA and transmission lens (8) is 2; The ion source assembly (2) is cylindrical in shape, the filament module (7) is disposed inside the cylinder, and the transmission lens (8) is disposed on the plane of the cylinder. Along the central axis of the ion source assembly (2), the arrangement order of the filament module (7) and the transmission lens (8) is: transmission lens (8), filament module (7), transmission lens (8).

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