An energy-filtering electronic detector system, detection method, and equipment
By combining a magnetic coil and an electrostatic deflection system, and adjusting the coil current and voltage, high-precision energy filtering is achieved, solving the problems of low energy resolution and signal strength loss in SEM energy filters, improving image quality and resolution, and simplifying system design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU SILICON TECH CO LTD
- Filing Date
- 2026-01-30
- Publication Date
- 2026-06-02
AI Technical Summary
In existing scanning electron microscopes (SEMs), energy filters have low energy resolution and are not pure, resulting in signal strength loss and decreased signal-to-noise ratio, complicated image contrast, and are highly dependent on detector position and geometry, making the system complex and expensive.
An energy-filtered electronic detector system is employed, which combines a magnetic coil deflection system and an electrostatic deflection system. By adjusting the coil current and voltage, the secondary electrons and backscattered electrons are effectively separated. A high vacuum environment is maintained using shielding components, and the signal is amplified by combining a scintillator and a photomultiplier tube module.
It achieves high-precision energy selection, effectively separates secondary electrons and backscattered electrons, improves image quality and resolution, avoids the central hole shadow effect, and enhances the reliability of the system and the purity of the image.
Smart Images
Figure CN122136247A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of scanning electron microscopy technology, specifically relating to an energy-filtering electron detector system, detection method, and device. Background Technology
[0002] The basic principle of scanning electron microscopy (SEM) is a multi-system collaborative process: Under high vacuum, an electron optics system generates an extremely fine electron probe, which, under the control of scanning coils, performs a raster-like scan of the sample surface, exciting various physical signals. The energy of these electrons contains information about the sample surface morphology, composition, and chemical state. The detector receives specific signals (such as SE or BSE) and converts them into electrical signals, which are then amplified and ultimately used to synchronously generate a microscopic image of the sample on a display screen. Several key signal electrons in SEM include secondary electrons (SE), backscattered electrons (BSE), and characteristic X-rays.
[0003] The image quality (contrast, signal-to-noise ratio, resolution) of a SEM largely depends on its detector system. Modern SEMs are typically equipped with multiple detectors to collect different types of signals to reveal different characteristics of the sample.
[0004] Energy filtering utilizes a physical mechanism to selectively detect electrons within a specific energy range while excluding electrons of other energies. This is analogous to adding an "energy filter" to a detector, allowing only the electrons of interest to pass through, thus enhancing compositional contrast, reducing charging effects, and distinguishing between different types of electron signals.
[0005] In SEM, there are two main methods for achieving energy filtering, corresponding to two common detector types: 1. Ring semiconductor detectors (the most common type) achieve filtering through bias voltage. This is the most popular and standard method of energy filtering and is usually integrated into the vacuum chamber of the SEM.
[0006] Advantages: Simple and easy to use, requiring only the adjustment of a knob or value on the software. Real-time filtering allows for real-time monitoring of the filtering effect. Low cost, making it a standard configuration for modern SEM.
[0007] However, it also has some inherent flaws and limitations: Low energy resolution and the inability to filter out "impure" electrons are the core drawbacks. The bias voltage method is based on a simple "potential barrier" model: electrons with kinetic energy greater than potential energy pass through, and vice versa. However, electron emission has a continuous energy spectrum with divergent directions, making it impossible to accurately separate SE and BSE: the so-called "SE mode" and "BSE mode" are only relative. Under low bias (SE mode), some high-angle, low-energy BSE electrons can still be detected. Similarly, under high bias (BSE mode), some abnormally high-energy secondary electrons may overcome the bias voltage and be detected.
[0008] Signal strength loss and signal-to-noise ratio (SNR) degradation occur because filtering essentially excludes a portion of the signal. When applying a high positive bias to filter electron beams (SE) to obtain a pure electron beam image, a large proportion of the SE signal is excluded. The total electron flow received by the detector is significantly reduced. To obtain acceptable image brightness, it may be necessary to increase the beam current or slow down the scan speed, but this can lead to problems such as increased electron beam damage, reduced depth of field, or longer analysis time. At low beam currents, the SNR of a pure BSE image is typically lower than that of a mixed SE / BSE image.
[0009] Image contrast can become more complex and increase the risk of misinterpretation. Energy filtering doesn't always make images easier to interpret; sometimes it can introduce complexity. In SE mode, edges and sharp points appear unusually bright due to the high probability of electron escape. This effect is reduced in high-bias BSE mode, but it doesn't disappear completely. This can lead to misjudgments of sample morphology.
[0010] The energy filtering effect of a ring detector is closely related to its physical location and geometry, and is highly dependent on the detector's position and geometry. Electrons of different energies have different angular distributions. BSEs have a wide emission angular distribution, while SEs have a more uniform angular distribution. The filter's efficiency is affected by the direction in which the electrons escape.
[0011] 2. Energy filtering via electromagnetic lenses. This is a more advanced and precise energy filtering method. How it works: An electromagnetic lens is used as an energy analyzer. Electrons of different energies are deflected differently by the Lorentz force when passing through the lens's magnetic field. By precisely controlling the lens's current (i.e., magnetic field strength), it can function like a monochromator, allowing only electrons of specific energies (or a very narrow energy range) to pass through a narrow slit and ultimately reach the detector.
[0012] Energy filtering effect: It can achieve very high-precision energy selection (energy resolution up to ~0.1 eV), which is far superior to the bias voltage method of ring detectors.
[0013] Advantages: Extremely high energy resolution. Capable of analyzing chemical composition and chemical states.
[0014] Disadvantages: The system is complex and expensive. The signal is relatively weak, and the imaging speed is slow.
[0015] To address the above-mentioned shortcomings and limitations, a new technology should be designed. Summary of the Invention
[0016] In view of the shortcomings of the prior art, the purpose of this invention is to provide an energy-filtering electronic detector system, detection method and device.
[0017] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: an energy-filtering electronic detector system, comprising: The microscope tube is used to generate electronic signals for signal deflection and has a vacuum environment. The microscope tube is equipped with a magnetic coil deflection system and an electrostatic deflection system. The scanning electron microscope extends into the microscope tube to generate electronic signals, which are deflected by the magnetic coil deflection system and the electrostatic deflection system.
[0018] The magnetic coil deflection system comprises multiple pole plates placed symmetrically in the center, each pole plate having a coil wound around it. By applying current to the coil, a magnetic field is generated. Adjusting the magnitude of the coil current produces different magnetic fields, which deflect the electron beam. An electrostatic deflection system includes multiple deflection plates and a grid on one of the deflection plates. A voltage is applied to each deflection plate and the grid to deflect the electron beam. The central axis of symmetry of the electrode plate and the electric deflection electrode plate coincides, and its central axis of symmetry is also the axis of the lens barrel; The detection system receives electronic information from inside the microscope tube and forms an image; The current and voltage driver module generates current to supply two plates and a coil, which generates a magnetic field to deflect the electron beam. At the same time, the current and voltage driver module generates voltage to supply two electric deflection plates, which generate an electric field to deflect the electron beam.
[0019] Furthermore, it also includes a shielding component to maintain a high vacuum environment. The shielding component is made of non-magnetic metal material and serves as a shielding shell to prevent interference and dissipate heat. Utilizing its excellent conductivity, high strength, high hardness, and low gas escape characteristics, it achieves precise electron beam collimation, effective heat dissipation, and maintenance of a high vacuum environment in key areas. It also includes an insulating base placed between the electrodes. It is precisely positioned between the electrodes to ensure that each electrode can maintain its independent and precise potential, thereby forming the required electrostatic field distribution. The shielding component and the insulating base together constitute a sealed and vacuum-sealed mirror tube.
[0020] Furthermore, the insulating base is a ceramic insulating base, and the high precision of ceramic ensures the accuracy and concentricity of the module installation.
[0021] Furthermore, the detection system includes a scintillator, a light guide, a photomultiplier tube module, and an image processor. The light guide is connected to the scintillator. The function of the light guide is to efficiently and losslessly transmit the light signal generated by the scintillator out of the vacuum chamber of the scanning electron microscope, i.e., the microscope tube. The end of the light guide is connected to the photomultiplier tube module. The photomultiplier tube module is an extremely sensitive photodetector with very high gain (amplification factor). After being amplified in the photomultiplier tube module, the photoelectrons enter the image processor. The electron beam scans the sample (wafer) surface point by point. The system of this invention collects a signal intensity value at each point, and this intensity value is mapped to the brightness of the corresponding pixel on the screen.
[0022] Furthermore, the image processor is a scanning electron microscope image processor.
[0023] Furthermore, the surface of the scintillator is coated with an extremely thin metal film, which reflects the light generated by the scintillator and transmits it backward. Furthermore, there are two electrodes, and the optimal number of electrically deflecting electrodes is set to two.
[0024] Furthermore, the number of plates and the number of electrically deflecting plates are equal.
[0025] A filtering method for an energy-filtering detector system, comprising: A1. The microscope tube is located above the wafer. The main electron beam generated inside the microscope tube hits the wafer surface, generating secondary electron signals and backscattered electron signals. The secondary electron signals and backscattered electron signals enter the detection system. A2. Applying current to the coil generates a magnetic field. The magnetic field strength is proportional to the ampere-turns. Adjusting the magnitude of the coil current produces different magnetic fields, which magnetically deflect the electron beam. A3. Applying voltage to the deflecting plates and grid generates electrical deflection of the electron beam; A4. Adjust the combination of magnetic deflection and electrical deflection to deflect the secondary electron signal and backscattered electron signal in a specific direction. The secondary electron signal and backscattered electron signal facing the grid pass through the grid and then enter the detection system. A5. Entering the photomultiplier tube module, it strikes the photocathode and excites photoelectrons through the photoelectric effect. The photoelectron signal is amplified to form a measurable, strong electrical signal, which is then sent to the image processor. The electron beam scans the sample surface point by point, and a signal intensity value is collected at each point. This intensity value is mapped to the brightness of the corresponding pixel on the screen.
[0026] An energy-filtering detector device, an device employing an energy-filtering electronic detector system.
[0027] Compared with the prior art, the advantages of the present invention include: (1) The present invention provides an energy filtering electronic detector system, detection method and equipment with a simple module structure, which realizes the combination of electric deflection and magnetic deflection through symmetrical plates and coils; (2) The present invention provides an energy-filtering electron detector system, detection method, and device that effectively separates secondary electrons and backscattered electrons by adjusting the bias voltage. By suspending the electrode plate on the wafer bias voltage, the secondary electron signal is effectively suppressed from entering the detector, and only the backscattered electron signal is collected. If the electrode plate is not suspended on the wafer bias voltage, stray secondary electron signals are collected, while high-energy backscattered electron signals with concentrated angles are filtered out. (3) The present invention provides an energy-filtering electron detector system, detection method and device, which utilizes a grid structure to directionally deflect secondary electrons and backscattered electrons, while filtering stray electron signals. (4) The present invention provides an energy-filtering electronic detector system, detection method and device. The off-axis structure design avoids the central hole shadow effect of the coaxial detector, prevents electrons from leaking out from the middle, and improves image quality and resolution. (5) The present invention provides an energy filtering electronic detector system, detection method and equipment, with shielding and electrical insulation design, which enhances the reliability of the module and prevents external electromagnetic interference and high voltage arcing risk. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 This is a schematic diagram illustrating the principles of electrostatic deflection and magnetic deflection. Figure 2 This is an overall schematic diagram of an energy-filtering electronic detector system, detection method, and device according to the present invention; Figure 3 This is a simulation diagram of the optical axis of an energy-filtering electronic detector system, detection method, and device according to the present invention. Figure 4 This is a simulation model diagram of an energy-filtering electronic detector system, detection method, and equipment according to the present invention; Figure 5 This is a diagram showing the potential and derivative distribution along the optical axis of an energy-filtering electronic detector system, detection method, and device according to the present invention. Figure 6This is a simulation diagram of the deflection efficiency trajectory of an energy-filtering electronic detector system, detection method, and device according to the present invention.
[0030] Figure label: 1. Shielding assembly; 2. Insulating base; 3. Electrode plate; 4. Electrode plate; 5. Electrically deflecting electrode plate; 6. Electrically deflecting electrode plate; 7. Grid; 8. Scintillator; 9. Light guide tube; 10. Photomultiplier tube module; 12. SEM image processor; 13. ; 14. Secondary electronic signal; 15. Backscattered electronic signal; 16. Wafer. Detailed Implementation
[0031] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution, its implementation process, and principles will be further explained below with reference to the accompanying drawings and specific implementation examples in the embodiments of this application.
[0032] It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, the present invention covers any substitutions, modifications, equivalent methods and solutions made on the spirit, principles and scope of the present invention as defined by the claims. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0033] In the description of this application, the terms "first," "second," "third," and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "a" or "one," and similar words, do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including," and similar words, mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including," and their equivalents, but do not exclude other elements or objects. The terms "connected" or "linked," and similar words, are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.
[0034] In the description of this application, the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, when using positional terms such as "both sides," "outer side," and "upper and lower," it should be understood that they are used only for ease of understanding and description, taking into account that the structure may be oriented to other positions.
[0035] In the description of this application, unless otherwise expressly specified and limited, the technical or scientific terms used shall have the ordinary meaning understood by a person with ordinary skills in the art to which this application pertains. Terms such as “installation,” “connection,” and “joining” shall be interpreted broadly, for example, as fixed connection, detachable connection, mating connection, or integral connection. For a person skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0036] The present invention aims to introduce and explain the structural composition of an energy-filtering electronic detector system, detection method and device, as well as the cooperation relationship between the various components. Unless otherwise specified, the size, material and manufacturing process of each component in the energy-filtering electronic detector system, detection method and device in the present invention can be selected according to specific circumstances, and no special limitations or explanations are made here.
[0037] Furthermore, to provide the public with a better understanding of the present invention, certain specific details are described in detail in the following description of the invention. However, those skilled in the art will fully understand the invention even without these detailed descriptions.
[0038] Example 1 Please see Figures 1-6 An energy-filtered electronic detector system, wherein the electronic signal is: in a high vacuum, the main electron beam 13 hits the surface of the wafer 16, generating a secondary electronic signal 14 and a backscattered electronic signal 15. The secondary electronic signal 14 and the backscattered electronic signal 15 enter the energy filter inside the lens tube, are deflected by the signal and detected. The microscope tube is used to generate electronic signals for signal deflection and has a vacuum environment. The microscope tube 1 is equipped with a magnetic coil deflection system and an electrostatic deflection system. The scanning electron microscope extends into the microscope tube 1 to generate electronic signals, which are deflected by the magnetic coil deflection system and the electrostatic deflection system.
[0039] The magnetic coil deflection system includes multiple pole plates (3, 4) placed symmetrically in the center. Here, there are two pole plates, which is the optimal number. Each pole plate is wound with a coil. By applying current to the coil, a magnetic field is generated. The magnetic field strength is proportional to the ampere-turns. By adjusting the magnitude of the coil current, different magnetic fields can be generated to deflect the electron beam. An electrostatic deflection system includes multiple deflection plates (5, 6) and a grid 7 provided on one of the deflection plates 6. Two deflection plates are provided. A voltage is applied to each deflection plate (5, 6) and the grid 7 to deflect the electron beam. The central axis of symmetry of the electrode plates (5, 6) and the electric deflection electrode plates (5, 6) coincides, and their central axis of symmetry is also the axis of the lens barrel; Adjusting the voltage on the electrodes (5, 6) can generate different electric field strengths, thus achieving different electron beam deflection capabilities. Adjusting the combination of magnetic and electric deflection can prevent the main electron beam 13 from being deflected, but can deflect the secondary electron signal 14 and the backscattered electron signal 15 in specific directions. The secondary electron signal 14 and the backscattered electron signal 15, which are directed toward the grid 7, pass through the grid 7 and are then received and imaged by the detection system. The detection system receives electronic information from inside the microscope tube and forms an image. The detection system is located on one side of the microscope tube and is a rangefinder design. The current and voltage driver module generates current to supply two electrodes and a coil, creating a magnetic field to deflect the electron beam. Simultaneously, the module generates voltage to supply two electrically deflecting electrodes, creating an electric field to deflect the electron beam. At this point, the voltage of the two electrically deflecting electrodes is suspended on the wafer bias. When the main electron beam 13 strikes the surface of wafer 16, the energies of the generated secondary electron signal 14 and backscattered electron signal 15 are primarily determined by the accelerating voltage U0 of the main electron beam 13 and the wafer bias Uwaferbias. The backscattered electron signal 15 is strongly correlated with the accelerating voltage, which directly determines the highest possible energy of the backscattered electrons. The energy of the secondary electron signal 14, however, is not directly related to the accelerating voltage; it is inherently low-energy. Due to its extremely low energy, its initial motion direction after escaping from the sample surface is random and diffuse. However, after passing through the bias voltage Uwaferbias of wafer 16, a strong directional collecting electric field is formed, which efficiently "attracts" the originally randomly moving low-energy secondary electrons to the detector, greatly enhancing the secondary electron signal. At the same time, the energy of the secondary electron signal 14 is determined by the potential difference between the detector surface and the surface potential difference of wafer 16. Therefore, if the electrode is suspended on the bias voltage Uwaferbias of wafer 16, the secondary electron signal 14 can be effectively suppressed from entering the detector, and only the backscattered electron signal 15 is collected. However, if the electrode (3, 4) is not suspended on the bias voltage Uwaferbias of wafer 16, since the energy of the backscattered electron signal 15 is much higher than that of the secondary electron signal 14, and the electrical and magnetic deflection distances are inversely proportional to the energy, the angularly scattered secondary electron signal 14 is more easily deflected onto the grid 7, passes through the grid 7 and is received by the detection system, while the angularly concentrated high-energy backscattered electron signal 15 is filtered out.
[0040] In one embodiment of the present invention, in addition to the above-described structure, it also includes a shielding component 1 for maintaining a high vacuum environment. The shielding component 1 is made of a non-magnetic metal material and serves as a shielding shell to prevent interference and dissipate heat. Utilizing its excellent conductivity, high strength, high hardness, and low gas escape characteristics, it achieves precise electron beam collimation, effective heat dissipation, and maintenance of a high vacuum environment in key areas. It also includes an insulating base 2 placed between the electrodes. The insulating base is a ceramic insulating base, precisely positioned between the electrodes to ensure that each electrode maintains its independent and precise potential, thereby forming the required electrostatic field distribution for electrical insulation, mechanical support, and thermal management between key components, while ensuring the high vacuum integrity of the equipment. The high precision of the ceramic ensures the accuracy and concentricity of the module installation. The shielding component 1 and the insulating base 2 together constitute a sealed and vacuum-sealed mirror tube.
[0041] In one embodiment of the present invention, in addition to the above-described structure, the detection system includes a scintillator 8, a light guide 9, a photomultiplier tube module 10, and an image processor 12. The deflected electronic signal (secondary electronic signal or backscattered electronic signal) strikes the scintillator 8. When high-energy electrons strike the scintillator, they excite it to emit photons (visible light). The scintillator 8 is located inside the microscope tube, and its surface is coated with a very thin metal film. The metal film reflects the light generated by the scintillator, allowing it to be transmitted backward. A long light guide 9 is connected to the scintillator 8. The function of the light guide 9 is to efficiently and losslessly transmit the light signal generated by the scintillator 8 out of the vacuum chamber (microscope tube) of the scanning electron microscope. The end of the light guide 9 is connected to the photomultiplier tube module 10. The photomultiplier tube module 10 is an extremely sensitive photodetector with very high gain (amplification). Photons enter the photomultiplier tube module 10, strike the photocathode, and excite photoelectrons through the photoelectric effect. These photoelectrons undergo secondary electron multiplication through a series of dynodes within the photomultiplier tube module 10, amplifying the signal to its original value. arrive The electron beam is multiplied by a factor of 1, ultimately forming a measurable and sufficiently strong electrical signal (current or voltage). This final electrical signal is then fed into the SEM image processor 12. The electron beam scans the sample surface point by point, and the invention acquires a signal intensity value at each point. This intensity value is mapped to the brightness of the corresponding pixel on the screen.
[0042] In one embodiment of the present invention, in addition to the above-described structure, the image processor is a scanning electron microscope image processor.
[0043] In one embodiment of the present invention, except for the structure described above, the number of electrode plates and the number of electrically deflecting electrode plates are equal.
[0044] A filtering method for an energy-filtering detector system, comprising: A1. The main electron beam 13 generated inside the lens tube hits the surface of the wafer 16, generating a secondary electron signal 14 and a backscattered electron signal 15. The secondary electron signal 14 and the backscattered electron signal 15 enter the detection system. A2. Applying current to the coil generates a magnetic field. The magnetic field strength is proportional to the ampere-turns. Adjusting the magnitude of the coil current produces different magnetic fields, which magnetically deflect the electron beam. A3. Applying voltage to the deflecting plates and grid generates electrical deflection of the electron beam; A4. Adjust the combination of magnetic deflection and electrical deflection to deflect the secondary electronic signal 14 and the backscattered electronic signal 15 in a specific direction. The secondary electronic signal 14 and the backscattered electronic signal 15, which are directed toward the grid 7, pass through the grid 7 and then enter the detection system. A5. The electron beam enters the photomultiplier tube module 10 and strikes the internal photocathode. Through the photoelectric effect, photoelectrons are excited. The photoelectron signal is amplified to form a measurable and strong electrical signal, which is then sent to the image processor 12. The electron beam scans the sample surface point by point and collects a signal intensity value at each point. This intensity value is mapped to the brightness of the corresponding pixel on the screen.
[0045] An energy-filtering detector device, an device employing an energy-filtering electronic detector system.
[0046] Energy filtering is achieved by combining an adjustable bias voltage and an electromagnetic lens. By adjusting the bias voltage, either high-energy backscattered electron (BSE) signals or low-energy secondary electron (SE) signals are actively detected. The electromagnetic lens combination effectively and accurately separates the SE and BSE signals, thereby extracting the components corresponding to specific physical properties from the mixed signal, resulting in a purer and more specific image. Simultaneously, the paraxial structure design avoids the central aperture shadow effect of coaxial detectors, improving image quality and resolution.
[0047] Understandable The core principle of energy-filtering electronic detector systems is the balance of forces. For example... Figure 1 As shown, it uses mutually perpendicular electric and magnetic fields to apply two forces in opposite directions to charged particles. Only when the particle's velocity satisfies a strict equilibrium condition can it pass through in a straight line without deflection. Its core components consist of two aspects: Electric field (E): Usually generated by a pair of parallel-plate capacitors, with the direction perpendicular to the expected path of the particle's motion.
[0048] Magnetic field (B): generated by a pair of coils, its direction is perpendicular to the electric field and also perpendicular to the direction of particle motion.
[0049] When a particle with charge q enters this combined field with velocity v, it will be subjected to two forces simultaneously: Electric force (F) e ):F e =qE. For electrons, the direction of the force is relative to the electric field. E is in the opposite direction, and this force attempts to push the particle toward one side of the capacitor plate.
[0050] Magnetic force (F) m This refers to the Lorentz force, Fm = qvB. Its direction is determined by the right-hand rule (for negative charges), and it is always perpendicular to the velocity v and the magnetic field. The plane containing B. This force attempts to make the particle move in a circular motion, pushing the particle to the opposite side of the electric field force.
[0051] When Fe =Fm,qE=qvB We get v=E / B, so the velocity depends only on the electric and magnetic fields and is independent of the particle's mass (m) and charge (q).
[0052] By carefully designing the directions of the electric and magnetic fields, these two forces can be made to be exactly opposite in direction. When the electric and magnetic forces are equal in magnitude and opposite in direction, the net force on the particle is zero, and it will maintain its original direction of motion, passing through the system in a straight line. Therefore, this design will not affect the main electron beam. However, for the returning secondary electrons or backscattered electrons, they will be deflected due to their different directions, and the deflection ability varies for electron signals of different energies.
[0053] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the protection scope of the present invention.
Claims
1. An energy-filtering electronic detector system, characterized in that: include: The microscope tube, used to generate, accelerate, and focus an electron beam, contains a magnetic coil deflection system and an electrostatic deflection system. The magnetic coil deflection system includes multiple pole plates placed symmetrically in the center, each pole plate is wound with a coil. By applying current to the coil, a magnetic field is generated. Adjusting the magnitude of the coil current generates different magnetic fields, which deflect the electron beam. The electrostatic deflection system includes multiple deflection plates and a grid on one of the deflection plates. A voltage is applied to each deflection plate and the grid to deflect the electron beam. The central axis of symmetry of the electrode plate and the electric deflection electrode plate coincides; The detection system receives electronic information from inside the microscope tube and forms an image; The current and voltage driver module generates current to supply two plates and a coil, which generates a magnetic field to deflect the electron beam. At the same time, the current and voltage driver module generates voltage to supply two electric deflection plates, which generate an electric field to deflect the electron beam.
2. The energy-filtering electronic detector system according to claim 1, characterized in that: It also includes a shielding assembly for maintaining a high vacuum environment, the shielding assembly being made of a non-magnetic metal material, serving as a shielding shell to prevent interference and dissipate heat; and an insulating base disposed between the electrodes, the insulating base serving for electrical insulation and mechanical support, the shielding assembly and the insulating base together forming a sealed and vacuum-sealed lens barrel.
3. The energy-filtering electronic detector system according to claim 2, characterized in that: The insulating base is a ceramic insulating base.
4. The energy-filtering electronic detector system according to claim 1, characterized in that: The detection system includes a scintillator, a light guide, a photomultiplier tube module, and an image processor. The light guide is connected to the rear of the scintillator and transmits the light signal generated by the scintillator to the lens barrel. The end of the light guide is connected to the photomultiplier tube module, and the photoelectrons are amplified in the photomultiplier tube module before entering the image processor.
5. The energy-filtering electronic detector system according to claim 1, characterized in that: The image processor is a scanning electron microscope image processor.
6. The energy-filtering electronic detector system according to claim 1, characterized in that: The surface of the scintillator is coated with a metal film to reflect the light generated by the scintillator.
7. An energy-filtering electronic detector system according to any one of claims 1-6, characterized in that: There are two electrodes, and there are two electrically deflecting electrodes.
8. The energy-filtering electronic detector system according to claim 7, characterized in that: The number of the electrodes and the number of the electric deflection electrodes are equal.
9. The filtering method of the energy filtering detector system according to claim 1, employing the method of the system according to any one of claims 1-7, characterized in that: include: A1. The main electron beam generated inside the lens tube hits the wafer surface, generating secondary electron signals and backscattered electron signals, which then enter the detection system. A2. Applying current to the coil generates a magnetic field. The magnetic field strength is proportional to the ampere-turns. Adjusting the magnitude of the coil current produces different magnetic fields, which magnetically deflect the electron beam. A3. Applying voltage to the deflecting plates and grid generates electrical deflection of the electron beam; A4. Adjust the combination of magnetic deflection and electrical deflection to deflect the secondary electron signal and backscattered electron signal in a specific direction. The secondary electron signal and backscattered electron signal facing the grid pass through the grid and then enter the detection system. A5. Entering the photomultiplier tube module, it strikes the photocathode and excites photoelectrons through the photoelectric effect. The photoelectron signal is amplified to form a measurable, strong electrical signal, which is then sent to the image processor. The electron beam scans the sample surface point by point, and a signal intensity value is collected at each point. This intensity value is mapped to the brightness of the corresponding pixel on the screen.
10. An energy filtering detector device, characterized in that: The device employs the system described in any one of claims 1-7.