Scanning method and apparatus

Abstract

The application relates to a scanning method and device. The method is applied to a deflection controller in a scanning device, and the method comprises the following steps: in response to an electron beam offset request, acquiring an initial scanning signal and a position offset amount of a target scanning center relative to the center of an initial scanning area corresponding to the initial scanning signal; generating a deflection signal based on the position offset amount; and controlling an electrostatic deflector based on the initial scanning signal and the deflection signal, so that the electron beam passing through the electrostatic deflector is scanned with the target scanning center as the scanning center and in a scanning mode corresponding to the initial scanning signal. The method can improve the measurement accuracy and efficiency and improve the compatibility.

Description

Technical Field

[0001] This application relates to the field of scanning electron microscopy, and in particular to a scanning method and scanning device. Background Technology

[0002] A scanning electron microscope (SEM) is a precision instrument that uses a focused electron beam to scan the surface of a sample to obtain information about its morphology and composition. In practical applications, when it is necessary to measure different locations on the sample surface, the scanning position of the electron beam is usually changed by moving the sample stage or by using the beam shift function.

[0003] Traditional electron beam deflection is achieved by adding a separate deflector to the electron optics system. This deflector is typically installed at a specific location on the electron beam path to precisely move the scanning position of the electron beam without moving the sample stage.

[0004] However, the above-mentioned solutions suffer from problems such as high mechanical complexity, limited adjustment accuracy, poor stability, and slow response speed, which affect measurement accuracy and efficiency. Summary of the Invention

[0005] Therefore, it is necessary to provide a scanning method and scanning device that can improve measurement accuracy and efficiency, as well as enhance compatibility, to address the aforementioned technical problems.

[0006] In a first aspect, this application provides a scanning method applied to a deflection controller in a scanning device, the scanning device further comprising an electrostatic deflector, the deflection controller being electrically connected to the electrostatic deflector, the method comprising:

[0007] In response to an electron beam deflection request, the initial scan signal and the position offset of the target scan center relative to the center of the initial scan region corresponding to the initial scan signal are obtained;

[0008] Based on the position offset, a deflection signal is generated;

[0009] The electrostatic deflector is controlled based on the initial scan signal and the deflection signal, so that the electron beam passing through the electrostatic deflector scans with the target scan center as the scan center, according to the scan mode corresponding to the initial scan signal.

[0010] In one embodiment, controlling the electrostatic deflector based on the initial scan signal and the deflection signal includes:

[0011] The amplitude of the initial scan signal is attenuated to obtain the intermediate scan signal;

[0012] The intermediate scanning signal and the deflection signal are superimposed to obtain the target scanning signal;

[0013] The electrostatic deflector is controlled based on the analog signal corresponding to the target scanning signal.

[0014] In one embodiment, the target scanning center includes the center of the target sub-scanning region within the initial scanning region corresponding to the initial scanning signal, and the attenuation processing of the amplitude of the initial scanning signal to obtain the intermediate scanning signal includes:

[0015] Obtain the preset attenuation coefficient;

[0016] The amplitude of the initial scan signal is attenuated based on the attenuation coefficient to obtain the intermediate scan signal;

[0017] The generation of the deflection signal based on the position offset includes:

[0018] A deflection signal is generated based on the positional offset of the center of the target sub-scanning region relative to the center of the initial scanning region; the electrostatic deflector is used to make the passing electron beam scan with the center of the target sub-scanning region as the scanning center, according to the scanning mode corresponding to the initial scan signal, based on the target scan signal.

[0019] In one embodiment, the initial scanning region is composed of multiple target sub-scanning regions, and generating a deflection signal based on the positional offset of the center of the target sub-scanning region relative to the center of the initial scanning region includes:

[0020] Multiple values ​​of DC deflection signals are generated based on the positional offset of the centers of the multiple target sub-scanning regions relative to the center of the initial scan region; the electrostatic deflector is used to ensure that the passing electron beam scans one by one with the centers of the multiple target sub-scanning regions as the scanning center, according to the scanning method corresponding to the initial scan signal, based on the target scan signal.

[0021] In one embodiment, the process includes, prior to controlling the electrostatic deflector based on the analog signal corresponding to the target scanning signal:

[0022] Obtain the preset amplitude threshold;

[0023] Based on the amplitude threshold, the target scanning signal is subjected to amplitude limiting processing.

[0024] In one embodiment, controlling the electrostatic deflector based on the initial scan signal and the deflection signal includes:

[0025] The electrostatic deflector is controlled by the superposition of the analog signal corresponding to the initial scanning signal and the analog signal corresponding to the deflection signal.

[0026] In one embodiment, acquiring the initial scan signal includes:

[0027] Obtain initial scan parameters, wherein the initial scan parameters include at least one of scan period and scan step size;

[0028] An initial scan signal is generated based on the initial scan parameters.

[0029] In one embodiment, the position offset includes an offset in a first direction and an offset in a second direction.

[0030] Secondly, this application also provides a scanning device, including a deflection controller and an electrostatic deflector, wherein the deflection controller is electrically connected to the electrostatic deflector;

[0031] The deflection controller is used to implement the steps of any of the methods described above.

[0032] In one embodiment, the deflection controller includes a field-programmable gate array (FPGA).

[0033] The aforementioned scanning method and equipment acquire an initial scanning signal and position offset in response to an electron beam deflection request. Based on the position offset, a deflection signal is generated, and the initial scanning signal and deflection signal are used together to control an electrostatic deflector. This allows the scanning center of the electron beam to be moved from the center of the initial scanning area to the target scanning center without changing the scanning mode corresponding to the initial scanning signal. Since only the existing electrostatic deflector in the scanning equipment needs to be reused, there is no need to add a separate deflection component. This simplifies the mechanical structure of the equipment, avoids mutual interference introduced by additional components, and avoids problems such as mechanical drift and changes in deflection sensitivity associated with additional deflectors. Furthermore, since the electron beam deflection is achieved by adjusting a digital signal, the positioning accuracy of the electron beam can be improved, and it can flexibly adapt to different measurement tasks. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart illustrating a scanning method in one embodiment;

[0036] Figure 2 This is a flowchart illustrating the steps for obtaining the initial scan signal in one embodiment;

[0037] Figure 3 This is a flowchart illustrating step 130 in one embodiment;

[0038] Figure 4 This is a flowchart illustrating the scanning method in another embodiment;

[0039] Figure 5 In one embodiment, when the attenuation coefficient α is A schematic diagram of multiple target sub-scanning regions included in the initial scan area;

[0040] Figure 6 This is a flowchart illustrating step 130 in another embodiment;

[0041] Figure 7 This is a flowchart illustrating the generation of a scanning signal for electron beam deflection through digital domain superposition in one embodiment.

[0042] Figure 8 This is a flowchart illustrating the generation of scanning signals for electron beam deflection through analog domain superposition in one embodiment.

[0043] Figure 9 This is a structural block diagram of a scanning device in one embodiment. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0045] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0046] In traditional technology, electron beam deflection is achieved by adding an independent deflector (such as a dedicated deflection coil) to the electron optics system. This additional deflector is installed at a specific location in the electron beam transmission path and generates a deflection electric field by applying an independent deflection signal, directly shifting the electron beam position. This deflection signal is a DC bias, which is physically independent of the AC scanning signal driving the grating scan. Furthermore, the original deflector uses a dedicated scanning waveform generator to generate a driving signal (used to generate a fast sawtooth wave in the X direction and a slow sawtooth wave in the Y direction, forming a two-dimensional grating scan trajectory), and its scanning range is fixed at the hardware level.

[0047] Based on this, embodiments of this application provide a scanning device, including a deflection controller and an electrostatic deflector, wherein the deflection controller is electrically connected to the electrostatic deflector; the deflection controller is used to respond to an electron beam deflection request to acquire an initial scanning signal and a positional offset of the target scanning center relative to the center of the initial scanning area corresponding to the initial scanning signal; generate a deflection signal based on the positional offset; and control the electrostatic deflector based on the initial scanning signal and the deflection signal, so that the electron beam passing through the electrostatic deflector scans with the target scanning center as the scanning center, according to the scanning mode corresponding to the initial scanning signal. Wherein:

[0048] The electrostatic deflector is an existing electrostatic deflector used in multiplexed scanning equipment to achieve raster scanning.

[0049] Exemplarily, the scanning device may further include a digital-to-analog converter (DAC) and a power amplifier. A deflection controller is electrically connected to the DAC, the DAC is electrically connected to the power amplifier, and the power amplifier is electrically connected to an electrostatic deflector. Specifically, the output of the deflection controller is electrically connected to the input of the DAC; the output of the DAC is electrically connected to the input of the power amplifier; and the output of the power amplifier is electrically connected to the input of the electrostatic deflector. Wherein:

[0050] A digital-to-analog converter (DAC) is used to convert the digital scan signal generated by the deflection controller (e.g., a digital signal resulting from the superposition of the initial scan signal and the deflection signal) into an analog scan signal. This analog scan signal includes an AC component corresponding to the initial scan signal and a DC component corresponding to the deflection signal.

[0051] A power amplifier is used to amplify the power of analog scanning signals.

[0052] An electrostatic deflector is used to shift the scanning center of the passing electron beam to the target scanning center based on the analog scanning signal after power amplification, and to perform scanning according to the scanning mode corresponding to the initial scanning signal.

[0053] In one exemplary embodiment, the deflection controller is a field-programmable gate array (FPGA).

[0054] Alternatively, the deflection controller described above can also be other devices used to generate digital waveform signals, such as a digital signal processor (DSP) or a microcontroller unit (MCU).

[0055] In one exemplary embodiment, such as Figure 1 As shown, a scanning method is provided. Taking the application of this method to a deflection controller in a scanning device as an example, the method includes the following steps 110 to 130. Wherein:

[0056] Step 110: In response to the electron beam offset request, obtain the initial scan signal and the position offset of the target scan center relative to the center of the initial scan area corresponding to the initial scan signal.

[0057] The initial scan signal can be a digital scan waveform. For example, the initial scan signal can be generated based on initial scan parameters. The initial scan signal corresponds to an initial scan area and a fixed scanning method (such as the line scan direction and interline stepping method of raster scanning). The initial scan area can refer to the complete original field of view (FOV) formed by the electron beam on the sample surface when the initial scan signal is output at full amplitude. Scanning methods include, but are not limited to, line-by-line raster scanning or frame-by-frame raster scanning. The initial scan signal can be a combination of a fast sawtooth wave in the X direction and a slow step wave in the Y direction.

[0058] For example, the electron beam offset request (such as the electron beam offset function enable signal) is monitored in real time. When the request is detected to be in an active state, the pre-stored or real-time generated initial scan signal is retrieved, and the relative offset of the current measurement point (i.e., the current scan center) relative to the target measurement point (i.e., the target scan center) is calculated.

[0059] In one exemplary embodiment, the position offset includes an offset in a first direction and an offset in a second direction. The first direction may be perpendicular to the second direction. For example, the position offset may include an offset ΔX in the X direction and an offset ΔY in the Y direction.

[0060] Alternatively, the position offset can also be represented in polar coordinates, including the offset radius and offset angle.

[0061] Step 120: Generate a deflection signal based on the position offset.

[0062] The deflection signal can be a digital DC bias signal.

[0063] For example, deflection signal components can be generated separately based on the position offset in each direction, and these components together constitute the deflection signal. The magnitude of the position offset is positively correlated with the magnitude of the corresponding deflection signal component.

[0064] Step 130: Control the electrostatic deflector based on the initial scan signal and the deflection signal so that the electron beam passing through the electrostatic deflector scans with the target scan center as the scan center and scans according to the scan mode corresponding to the initial scan signal.

[0065] For example, an analog scanning signal can be generated from an initial scanning signal and a deflection signal using a digital-to-analog converter. This analog scanning signal includes an AC component corresponding to the initial scanning signal and a DC component corresponding to the deflection signal. The analog scanning signal is then amplified using a power amplifier. An electrostatic deflector is used to ensure that the electron beam scans around the target scanning center according to the scanning pattern corresponding to the initial scanning signal, based on the amplified analog scanning signal.

[0066] Understandably, the deflection signal is used to shift the overall scanning trajectory of the electron beam after passing through the electrostatic deflector. The initial scan signal determines the scanning method of the electron beam and the size of the scanning area. The size of the scanning area can remain the original size or change according to the actual configuration. For example, the amplitude of the initial scan signal can be attenuated to obtain an intermediate scan signal, and the electrostatic deflector can be controlled based on the intermediate scan signal and the deflection signal.

[0067] In the aforementioned scanning method, an initial scanning signal and position offset are acquired in response to an electron beam deflection request. A deflection signal is generated based on the position offset, and the initial scanning signal and deflection signal are used together to control the electrostatic deflector. This allows the scanning center of the electron beam to be moved from the center of the initial scanning area to the target scanning center without changing the scanning mode corresponding to the initial scanning signal. Since only the existing electrostatic deflector in the scanning equipment needs to be reused, there is no need to add a separate deflection component. This simplifies the mechanical structure of the equipment, avoids mutual interference introduced by additional components, and avoids problems such as mechanical drift and changes in deflection sensitivity that exist with additional deflectors. Furthermore, since the deflection of the electron beam is achieved by adjusting the digital signal, the positioning accuracy of the electron beam can be improved, and it can be flexibly adapted to different measurement tasks.

[0068] In one exemplary embodiment, such as Figure 2 As shown, the steps for obtaining the initial scan signal described above may include:

[0069] Step A1: Obtain the initial scan parameters, which include at least one of the scan cycle and scan step size.

[0070] For example, the initial scan parameters, the electron beam offset function enable signal, and the position offset (such as ΔX, ΔY) of the target scan center relative to the center of the initial scan region corresponding to the initial scan signal can be acquired simultaneously. In addition, the initial scan parameters may also include waveform attenuation coefficient α, power amplification gain G, etc.

[0071] Step A2: Generate the initial scan signal based on the initial scan parameters.

[0072] For example, a full-width initial scan signal V can be generated based on the scan cycle and scan step size. full It is understandable that when the electron beam offset function is not enabled, a conventional raster scan can be performed using a full-width initial scan signal; when the electron beam offset function is enabled, the full-width initial scan signal can be attenuated according to the waveform attenuation coefficient α.

[0073] In this embodiment, by acquiring the scan period and scan step size and generating an initial scan signal based on them, the programmable configuration of the digital scan waveform can be achieved.

[0074] In one exemplary embodiment, such as Figure 3 As shown, step 130 above may include:

[0075] Step 310: Attenuate the amplitude of the initial scan signal to obtain the intermediate scan signal.

[0076] Understandably, attenuating the amplitude of the initial scan signal will reduce the scan coverage area (i.e., FOV).

[0077] Step 320: The intermediate scanning signal and the deflection signal are superimposed to obtain the target scanning signal.

[0078] For example, the intermediate scan signal and the deflection signal can be directly added in the digital domain to obtain the target scan signal. This target scan signal includes an attenuated AC scan component and a DC bias component.

[0079] Step 330: Control the electrostatic deflector based on the analog signal corresponding to the target scanning signal.

[0080] For example, the target scanning signal can be transmitted to a digital-to-analog converter (DAC) to convert the target scanning signal from digital to analog, obtaining a corresponding analog signal. This analog signal is amplified by a power amplifier and applied to the electrodes of an electrostatic deflector, thereby controlling the deflection of the electron beam. It is understood that, since the target scanning signal contains both attenuated AC scanning components and DC bias components, the scanning trajectory of the electron beam on the sample surface is a reduced grating scanning pattern, and the center of the entire scanning pattern is shifted to the target scanning center.

[0081] In this embodiment, by attenuating the amplitude of the initial scanning signal, the scanning coverage of the electron beam can be reduced, compressing the originally large initial scanning area into a local sub-region. Furthermore, by superimposing the attenuated intermediate scanning signal with the deflection signal, the reduced sub-region can be shifted to any target position within the initial scanning area. Thus, a refined scan of a specific local area within the initial scanning area can be performed without moving the sample stage or changing the scanning method.

[0082] Furthermore, such as Figure 4 As shown, the target scanning center may include the center of the target sub-scanning region in the initial scanning region corresponding to the initial scanning signal, and step 130 may further include:

[0083] Step 3101: Obtain the preset attenuation coefficient.

[0084] Step 3102: Attenuate the amplitude of the initial scan signal based on the attenuation coefficient to obtain the intermediate scan signal.

[0085] For example, the preset attenuation coefficient can be expressed as α ( In one possible implementation, the attenuation coefficient can be determined based on the size of the target sub-scan region. It is understood that the smaller the attenuation coefficient α, the smaller the scanning range corresponding to the intermediate scan signal. For example, the attenuation coefficient can be set by the user through host computer software, or it can be automatically calculated by the deflection controller based on the ratio of the side length of the target sub-scan region to the side length of the initial scan region.

[0086] At this time, step 120 above may include: generating a deflection signal based on the positional offset of the center of the target sub-scanning region relative to the center of the initial scanning region; the electrostatic deflector is used to make the passing electron beam scan with the center of the target sub-scanning region as the scanning center, according to the scanning method corresponding to the initial scan signal, based on the target scan signal.

[0087] For example, when it is only necessary to move the scanning center to the center of a specific sub-region within the initial scanning area, a DC deflection signal value can be calculated based on the positional offset (ΔX, ΔY) of the center of the target sub-scanning region relative to the center of the initial scanning region. Specifically, the coordinates of the center of the target sub-scanning region in the coordinate system of the initial scanning region can be obtained; according to a preset conversion coefficient (such as the scanning displacement corresponding to each volt), the offset is converted into a digital domain DC bias value (such as including two components in the X and Y directions); this DC bias value is output as the only deflection signal and superimposed with the attenuated intermediate scanning signal to obtain the target scanning signal; the electrostatic deflector, based on this target scanning signal, fixes the scanning center of the electron beam at the center of the target sub-scanning region and scans only this sub-region according to the original scanning method (such as raster scanning).

[0088] In this embodiment, by obtaining a preset attenuation coefficient, the reduction ratio of the scanning range can be flexibly controlled according to actual observation needs. Since the attenuation coefficient can be preset or dynamically adjusted, the size of the local sub-region is configurable, thereby adapting to the fine observation requirements of different scales. At the same time, a deflection signal is generated based on the offset of the center of the target sub-scanning region relative to the center of the initial scanning region, which can accurately align the attenuated scanning field of view with the target region of interest.

[0089] Optionally, the initial scanning area may be composed of multiple target sub-scanning areas, and step 120 may include: generating multiple values ​​of DC deflection signal based on the positional offset of the center of the multiple target sub-scanning areas relative to the center of the initial scanning area; the electrostatic deflector is used to make the passing electron beam scan with the center of the multiple target sub-scanning areas as the scanning center, according to the scanning method corresponding to the initial scanning signal, based on the target scanning signal.

[0090] For example, when multiple sub-regions within the initial scanning area need to be measured sequentially, the corresponding DC deflection signal value can be calculated based on the offset of the center of each sub-region relative to the center of the initial scanning area. The deflection controller outputs one DC deflection value in each time slice according to a preset scanning order (e.g., arranged row by row from left to right or top to bottom), and superimposes it with the same attenuated intermediate scanning signal to generate the target scanning signal for the current sub-region. Based on the sequentially generated target scanning signals, the electrostatic deflector causes the scanning center of the electron beam to jump to the center of each sub-region, and completes the scanning of each sub-region according to the original raster scanning method. After each sub-region is scanned, the deflection controller automatically updates the deflection signal to the DC bias value corresponding to the next sub-region.

[0091] In one possible implementation, when it is necessary to divide the initial scan area into multiple target sub-scan areas, the attenuation coefficient can be determined based on the number of target sub-scan areas. Please refer to [reference needed]. Figure 5 , Figure 5 In one embodiment, when the attenuation coefficient α is This is a schematic diagram showing the multiple target sub-scanning regions included in the initial scan area. It can be understood that when the attenuation coefficient α = At that time, the initial scan area (original FOV) was divided into 9 equally sized target sub-scan areas of 3×3 (e.g., Figure 5 (K0 to K8 in the original FOV). The deflection controller places the initial scanning region of the electron beam in the central sub-region of the original FOV (e.g., K4) and adjusts the DC deflection signal. The value of is set so that the current scan center is located at the center of K4. In this way, the electron beam can be shifted to the surrounding 8 sub-regions (K0, K1, K2, K3, K5, K6, K7, K8) in four directions (up, down, left, and right), which facilitates continuous beam shift in multiple directions and regions.

[0092] In this embodiment, by generating multiple DC deflection signal values ​​and controlling the electron beam to switch scanning centers one by one, it is possible to achieve automatic sequential scanning of multiple sub-regions within the initial scanning area without repeated manual intervention, thereby improving the efficiency of batch measurement or continuous observation.

[0093] Optionally, such as Figure 6 As shown, step 310 above may further include:

[0094] Step 3401: Obtain the preset amplitude threshold.

[0095] The preset amplitude threshold can be determined based on the full amplitude of the digital input of the digital-to-analog converter or the boundary value of the linear input range of the power amplifier.

[0096] Step 3402: Based on the amplitude threshold, the target scanning signal is subjected to amplitude limiting processing.

[0097] For example, when the amplitude of the target scanning signal is greater than the amplitude threshold, the amplitude of the target scanning signal can be clamped and limited to the amplitude threshold to complete the digital domain amplitude limiting and prevent the amplitude of the analog signal after subsequent digital-to-analog conversion from exceeding the limit.

[0098] In this embodiment, by performing amplitude limiting processing on the target scanning signal, it is possible to prevent the superimposed signal from exceeding the full-amplitude range of the digital-to-analog converter or power amplifier, thereby avoiding signal distortion or device damage.

[0099] In one possible implementation, please refer to Figure 7 , Figure 7This is a flowchart illustrating the generation of a scanning signal for electron beam deflection using digital domain superposition in one embodiment. Wherein, V g It is a digital scanning waveform generated by the deflection controller based on the scanning waveform parameters, where G is the power amplification gain and V is the voltage drop gain. out It is the analog scanning signal output by the power amplifier:

[0100] (1)

[0101] Among them, V g The target scanning signal consists of two parts:

[0102] (2)

[0103] in, That is, the deflection signal. That is, the intermediate scan signal. ( This determines the area covered by the scan. The attenuation coefficient of the scanning waveform. This is the maximum value of the digital scan waveform, which is also the original scan waveform. The offsets in the X and Y directions superimposed on the original scanning waveform determine the center position of the scanning area. Based on the relative offsets (ΔX, ΔY) between the current measurement point and the target measurement point, and combined with the scanning waveform parameters, the following is obtained using an FPGA algorithm:

[0104] (3)

[0105] According to formulas 1 to 3 above, for a given gain value G, When it is 1, then Full-width output, at this time Zero, maximum, Maximum, maximum scanning range. Implementing Beam shift functionality requires... right Scaling, After scaling, its corresponding FOV will also decrease, and through Adjust the current FOV to the original FOV center. Please continue to refer to [the relevant documentation]. Figure 5 ,when At that time, the original FOV was divided into 9 zones, and adjustments were made. The value of is set so that the initialization location of BeamShift is at K4, and the other areas are used to implement BeamShift, and BeamShift needs to ensure that To prevent the amplitude of the scan waveform from exceeding the maximum value.

[0106] Specifically, when Beam Shift is disabled, the XY offset is 0, and the waveform attenuation coefficient is... When the value is 1, normal scanning is performed, and the scanning range is at its maximum. When Beam Shift is enabled, the value is determined based on the XY offset and... The initial scan area is placed at the center of the original FOV, which facilitates beam shifting in different directions. This can be done based on scan parameters such as scan cycle, scan step size, and attenuation coefficient. Generate attenuated digital scan waveform The offset signal is obtained based on the offsets in the X and Y directions. .right and The final digital scan waveform is obtained by superimposing the two digital waveforms. Then The analog voltage signal is obtained by converting the digital-to-analog converter; the amplified analog voltage signal is applied to the electrostatic deflector, causing the electron beam to be deflected towards the scanning area of ​​the target measurement point under the action of the electric field and the scanning is completed.

[0107] In an exemplary embodiment, step 130 may include controlling an electrostatic deflector based on a superposition signal of the analog signal corresponding to the initial scan signal and the analog signal corresponding to the deflection signal.

[0108] For example, the initial scan signal can be transmitted to a digital-to-analog converter (DAC) so that the DAC performs digital-to-analog conversion on the initial scan signal to obtain an analog AC scan signal; the deflection signal can be transmitted to a DAC so that the DAC performs digital-to-analog conversion on the deflection signal to obtain an analog DC deflection signal; the analog AC scan signal and the analog DC deflection signal can be superimposed to obtain an analog scan signal.

[0109] In one possible implementation, please refer to Figure 8 , Figure 8 This is a flowchart illustrating the generation of a scanning signal for electron beam deflection using analog domain superposition in one embodiment. It is the original digital scan waveform (i.e., the initial scan signal). , It can be generated by a separate hardware module. It is a digital deflection signal. It can be generated by a separate hardware module. The digital signals generated by the two hardware modules are converted into analog signals by a digital-to-analog converter, then superimposed, and finally amplified to obtain the final analog scanning signal. The final result is:

[0110] (4)

[0111] Understandably, the original waveform is not shown here. To attenuate, therefore Always equal to In other words, when Beam Shift is activated, the FOV remains at its original size, and can be adjusted by changing... The values ​​are then superimposed on the circuit to perform Beam Shift.

[0112] Specifically, when beam shift is disabled, the XY offset is 0, and the waveform attenuation coefficient is no longer needed. At this point, normal scanning is performed, and the scanning range is at its maximum. When Beam Shift is enabled, the scanning range remains unchanged, maintaining the maximum range for scanning. Based on the XY offset, Beam Shift can be performed in different directions while maintaining the original FOV size. Full-amplitude digital scan waveforms can be generated based on scanning parameters such as the scan cycle and scan step size. The digital offset signal is obtained based on the offsets in the X and Y directions. ;right and The two digital waveforms are converted from analog to digital and then superimposed on the hardware module to obtain the accumulated analog voltage signal. The amplified analog voltage signal is applied to the electrostatic deflector, causing the electron beam to deflect towards the scanning area of ​​the target measurement point under the action of the electric field and complete the scanning.

[0113] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0114] Based on the same inventive concept, this application also provides a scanning apparatus for implementing the scanning method described above. The solution provided by this apparatus is similar to the implementation described in the above method; therefore, specific limitations in one or more scanning apparatus embodiments provided below can be found in the limitations of the scanning method described above, and will not be repeated here.

[0115] In one exemplary embodiment, such as Figure 9 As shown, a scanning device 900 is provided, which is applied to a deflection controller in a scanning device. The scanning device 900 includes: an acquisition module 901, a generation module 902, and a control module 903, wherein:

[0116] The acquisition module 901 is used to acquire the initial scan signal and the position offset of the target scan center relative to the center of the initial scan area corresponding to the initial scan signal in response to the electron beam offset request.

[0117] The generation module 902 is used to generate a deflection signal based on the position offset.

[0118] The control module 903 is used to control the electrostatic deflector based on the initial scan signal and the deflection signal, so that the electron beam passing through the electrostatic deflector scans with the target scan center as the scan center and scans according to the scan mode corresponding to the initial scan signal.

[0119] In one embodiment, the control module 903 includes:

[0120] The attenuation processing submodule is used to attenuate the amplitude of the initial scan signal to obtain the intermediate scan signal.

[0121] The superposition processing submodule is used to superimpose the intermediate scan signal and the deflection signal to obtain the target scan signal.

[0122] The control submodule is used to control the electrostatic deflector based on the analog signal corresponding to the target scanning signal.

[0123] In one embodiment, the target scanning center includes the center of the target sub-scanning region in the initial scanning region corresponding to the initial scanning signal, and the attenuation processing submodule includes:

[0124] The coefficient acquisition unit is used to acquire the preset attenuation coefficient.

[0125] The attenuation processing unit is used to attenuate the amplitude of the initial scan signal based on the attenuation coefficient to obtain the intermediate scan signal.

[0126] Furthermore, the aforementioned generation module 902 is also used for:

[0127] A deflection signal is generated based on the positional offset of the center of the target sub-scanning region relative to the center of the initial scanning region. An electrostatic deflector is used to ensure that the passing electron beam scans with the center of the target sub-scanning region as the scanning center, according to the scanning method corresponding to the initial scan signal, based on the target scan signal.

[0128] In one embodiment, the initial scanning region is composed of multiple target sub-scanning regions, and the generation module 902 is further configured to:

[0129] Multiple DC deflection signal values ​​are generated based on the positional offset of the center of each of the multiple target sub-scanning regions relative to the center of the initial scan region. The electrostatic deflector is used to ensure that the passing electron beam scans one by one with the center of each of the multiple target sub-scanning regions as the scanning center, according to the scanning method corresponding to the initial scan signal.

[0130] In one embodiment, the control module 903 further includes a limiting processing submodule, which includes:

[0131] The threshold acquisition unit is used to acquire a preset amplitude threshold.

[0132] Amplitude limiting processing unit is used to perform amplitude limiting processing on the target scanning signal based on an amplitude threshold.

[0133] In one embodiment, the control module 903 is further configured to:

[0134] The electrostatic deflector is controlled by the superposition of the analog signal corresponding to the initial scanning signal and the analog signal corresponding to the deflection signal.

[0135] In one embodiment, the acquisition module 901 includes:

[0136] The parameter acquisition submodule is used to acquire the initial scan parameters, which include at least one of the scan cycle and scan step size.

[0137] The signal generation submodule is used to generate the initial scan signal based on the initial scan parameters.

[0138] In one embodiment, the aforementioned position offset includes an offset in a first direction and an offset in a second direction.

[0139] Each module in the aforementioned scanning device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of the electronic device in hardware form or independent of it, or stored in the memory of the electronic device in software form, so that the processor can call and execute the operations corresponding to each module.

[0140] In one exemplary embodiment, an electronic device is provided, including a memory and a processor, wherein the memory stores a program, and the processor executes the program to implement the steps in the above-described method embodiments.

[0141] In one embodiment, a readable storage medium is provided on which a program is stored, which, when executed by a processor, implements the steps in the above method embodiments.

[0142] In one embodiment, a program product is provided, including a program that, when executed by a processor, implements the steps in the above method embodiments.

[0143] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0144] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0145] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A scanning method, characterized in that, A deflection controller used in a scanning device, the scanning device further including an electrostatic deflector, the deflection controller being electrically connected to the electrostatic deflector, the method comprising: In response to an electron beam deflection request, the initial scan signal and the position offset of the target scan center relative to the center of the initial scan region corresponding to the initial scan signal are obtained; Based on the position offset, a deflection signal is generated; The electrostatic deflector is controlled based on the initial scan signal and the deflection signal, so that the electron beam passing through the electrostatic deflector scans with the target scan center as the scan center, according to the scan mode corresponding to the initial scan signal.

2. The method according to claim 1, characterized in that, The control of the electrostatic deflector based on the initial scan signal and the deflection signal includes: The amplitude of the initial scan signal is attenuated to obtain the intermediate scan signal; The intermediate scanning signal and the deflection signal are superimposed to obtain the target scanning signal; The electrostatic deflector is controlled based on the analog signal corresponding to the target scanning signal.

3. The method according to claim 2, characterized in that, The target scanning center includes the center of the target sub-scanning region within the initial scanning region corresponding to the initial scanning signal. The attenuation process of the amplitude of the initial scanning signal to obtain the intermediate scanning signal includes: Obtain the preset attenuation coefficient; The amplitude of the initial scan signal is attenuated based on the attenuation coefficient to obtain the intermediate scan signal; The generation of the deflection signal based on the position offset includes: A deflection signal is generated based on the positional offset of the center of the target sub-scanning region relative to the center of the initial scanning region; the electrostatic deflector is used to make the passing electron beam scan with the center of the target sub-scanning region as the scanning center, according to the scanning mode corresponding to the initial scan signal, based on the target scan signal.

4. The method according to claim 3, characterized in that, The initial scanning region is composed of multiple target sub-scanning regions, and the generation of a deflection signal based on the positional offset of the center of the target sub-scanning region relative to the center of the initial scanning region includes: Multiple values ​​of DC deflection signals are generated based on the positional offset of the centers of the multiple target sub-scanning regions relative to the center of the initial scan region; the electrostatic deflector is used to ensure that the passing electron beam scans one by one with the centers of the multiple target sub-scanning regions as the scanning center, according to the scanning method corresponding to the initial scan signal, based on the target scan signal.

5. The method according to claim 2, characterized in that, Before controlling the electrostatic deflector based on the analog signal corresponding to the target scanning signal, the following steps are included: Obtain the preset amplitude threshold; Based on the amplitude threshold, the target scanning signal is subjected to amplitude limiting processing.

6. The method according to claim 1, characterized in that, The control of the electrostatic deflector based on the initial scan signal and the deflection signal includes: The electrostatic deflector is controlled by the superposition of the analog signal corresponding to the initial scanning signal and the analog signal corresponding to the deflection signal.

7. The method according to claim 1, characterized in that, The acquisition of the initial scan signal includes: Obtain initial scan parameters, wherein the initial scan parameters include at least one of scan period and scan step size; An initial scan signal is generated based on the initial scan parameters.

8. The method according to claim 1, characterized in that, The position offset includes the offset in the first direction and the offset in the second direction.

9. A scanning device, characterized in that, It includes a deflection controller and an electrostatic deflector, wherein the deflection controller is electrically connected to the electrostatic deflector; The deflection controller is used to implement the steps of the method according to any one of claims 1 to 8.

10. The scanning device according to claim 9, characterized in that, The deflection controller includes a field-programmable gate array.

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