Correction method, electron microscope, medium and program product
By automatically adjusting parameters through model calculations, the electron microscope was able to resolve the issue of sample image shift caused by electron beam deviation, simplifying the calibration process and improving efficiency and image quality.
Patent Information
- Application Number
- CN202511104939.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-07
- Publication Date
- 2025-11-14
AI Technical Summary
When the operating parameters of an electron microscope are changed, the electron beam may shift, causing the sample image to shift. Manual adjustment is tedious and time-consuming, making it difficult to achieve accurate calibration.
By acquiring the target and current operating parameters, the model is used to calculate and adjust the parameters, automatically adjusting the electron microscope to compensate for electron beam offset, including electron beam offset data, mechanical stage movement, etc., to achieve precise correction.
It eliminates the need for manual user operation, simplifies the calibration process, improves calibration efficiency, reduces the probability of sample image shift, and enhances image quality.
Smart Images
Figure CN120954952A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electron microscopy technology, and in particular to a calibration method, an electron microscope, media, and program products. Background Technology
[0002] An electron microscope is a microscope that uses a high-energy electron beam instead of visible light as a light source, and forms an image of the sample by the signal generated by the interaction between the electron beam and the sample.
[0003] During the operation of an electron microscope, the operating parameters of the electron microscope can be changed to obtain sample information or improve the image quality of the sample image.
[0004] However, changing the operating parameters of an electron microscope can cause the electron beam to shift, resulting in a shift in the sample image, or even preventing the sample image from being displayed in the electron microscope's field of view. In such cases, the user (electron microscope operator) usually needs to manually adjust the image (e.g., move the electron microscope's sample stage or adjust the electron beam shift data) to center the sample image in the field of view, which is tedious and time-consuming. Summary of the Invention
[0005] The purpose of this application is to provide a calibration method, an electron microscope, media, and a procedure product.
[0006] The first aspect of this application provides a calibration method applied to an electron microscope. The method includes: acquiring a target operating parameter and a current operating parameter of the electron microscope; inputting the target operating parameter and the current operating parameter into a first model and acquiring a first adjustment parameter output by the first model, wherein the first model is determined based on different operating parameters of the electron microscope and electron beam offset data corresponding to different operating parameters, and the first adjustment parameter is used to compensate for the electron beam offset data of the electron microscope after switching from the current operating parameter to the target operating parameter; switching the current operating parameter to the target operating parameter, and adjusting the electron microscope based on the first adjustment parameter.
[0007] In this embodiment, the adjustment parameters are determined by a model, enabling more accurate correction without requiring manual user intervention. This method is simple, quick, reduces calibration difficulty, and improves calibration efficiency. Furthermore, the correction method provided in this embodiment can reduce the probability of sample image shift.
[0008] In one possible implementation of the first aspect described above, the electron beam offset data includes at least one of the following: the offset vector of the electron beam in a preset coordinate system, the rotation angle of the electron beam in the preset coordinate system, and the relative relationship between the electron beam and the mechanical stage of the electron microscope.
[0009] In one possible implementation of the first aspect described above, the first adjustment parameter includes at least one of the following: position, focal distance, astigmatism, and centering.
[0010] In one possible implementation of the first aspect described above, corresponding to the first adjustment parameter being position, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the electron beam offset data of the electron microscope, adjusting the movement data of the mechanical stage of the electron microscope; or, corresponding to the first adjustment parameter being focal length, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the movement data of the mechanical stage of the electron microscope, adjusting the current value of the magnetic coil of the electron microscope, adjusting the voltage value of the electrostatic field of the electron microscope; or, corresponding to the first adjustment parameter being astigmatism, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the current value of the magnetic coil of the electron microscope, adjusting the voltage value of the electrostatic field of the electron microscope; or, corresponding to the first adjustment parameter being centering, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the current value of the magnetic coil of the electron microscope, adjusting the voltage value of the electrostatic field of the electron microscope.
[0011] In this embodiment, if nanoscale observation of the sample is required, corresponding to the first adjustment parameter being position, the electron microscope 100 is adjusted by jointly adjusting the electron beam offset data and the movement data of the mechanical stage. Specifically, this can be achieved by: performing micrometer-level movement based on the mechanical stage movement, and then performing the remaining correction based on the electron beam offset. In this way, the problem of image quality degradation caused by excessive electron beam offset can be avoided as much as possible, thereby improving the image quality of the sample image.
[0012] In one possible implementation of the first aspect described above, the method further includes: acquiring a target image of a first sample based on the adjusted electron microscope and target operating parameters; comparing the target image with a first image of the first sample corresponding to the current operating parameters; corresponding to a reference feature point in the first image being in the target image, and the deviation between the position of the reference feature point in the first image and its position in the target image being greater than a preset deviation threshold, or, the first image not containing a reference feature point; adjusting the operating parameters of the electron microscope, and acquiring a second image of the first sample after adjusting the operating parameters of the electron microscope; corresponding to a reference feature point in the first image being in the second image, and the deviation between the position of the reference feature point in the first image and its position in the second image being less than or equal to a preset deviation threshold; updating the first model based on the difference between the position of the reference feature point in the second image and the position of the reference feature point in the first image.
[0013] In this embodiment of the application, after the electron microscope 100 completes the calculation and compensation of the target working parameters, it acquires the sample image (i.e., the target image) under the target working parameters and compares it with the sample image (i.e., the first image) under the current working parameters. The positional relationship of the defined reference feature points in the image determines whether the adjustment is completed.
[0014] In one possible implementation of the first aspect described above, the method further includes: corresponding to a reference feature point in the first image in the second image, and the deviation between the position of the reference feature point in the first image and its position in the second image is greater than a preset deviation threshold, or, there is no reference feature point in the second image; switching the target working parameter to the current working parameter, reducing the magnification of the electron microscope, and inputting the target working parameter and the current working parameter into the first model, and obtaining the second adjustment parameter output by the first model, wherein the second adjustment parameter is used to compensate for the electron beam offset data of the electron microscope after switching from the current working parameter to the target working parameter; switching the current working parameter to the target working parameter, and adjusting the electron microscope based on the second adjustment parameter.
[0015] In one possible implementation of the first aspect described above, the operating parameters include at least one of the following: acceleration voltage, operating distance, electromagnetic lens current, electrostatic field voltage, aperture deflection coil current, centering coil current, and astigmatism coil current.
[0016] In one possible implementation of the first aspect described above, the type of electron microscope includes at least one of the following: a scanning electron microscope, a dual-beam electron microscope with electron beam imaging capability, and a multi-beam electron microscope with electron beam imaging capability.
[0017] A second aspect of this application provides an electron microscope, comprising: a memory for storing instructions executed by one or more processors of the electron microscope, and a processor for performing any of the methods described in the first aspect above.
[0018] A third aspect of this application provides a computer-readable medium storing instructions that, when executed on an electron microscope, cause the electron microscope to perform any of the methods described in the first aspect above.
[0019] The fourth aspect of this application provides a program product including instructions that, when executed on an electron microscope, cause the electron microscope to perform any of the methods described in the first aspect above. Attached Figure Description
[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 A schematic diagram of a scanning electron microscope is shown according to an embodiment of this application;
[0022] Figure 2 A schematic diagram illustrating the implementation process of a correction method is shown in the embodiments of this application;
[0023] Figure 3 A coordinate diagram is shown according to an embodiment of this application;
[0024] Figure 4 An embodiment of this application illustrates a schematic diagram of the implementation process of another correction method;
[0025] Figure 5 A schematic diagram of the structure of an electron microscope 100 is shown according to an embodiment of this application. Detailed Implementation
[0026] The illustrative embodiments of this application include, but are not limited to, a calibration method, an electron microscope, media, and program products.
[0027] An electron microscope (EM) is an instrument that uses the interaction of an electron beam with a sample to observe its microstructure. The resolution of an electron microscope is far superior to that of an optical microscope; for example, the resolution of an electron microscope can reach the nanometer or even sub-nanometer level. Therefore, electron microscopes can provide more detailed information about microstructures, such as the ultrastructure of cells (cell membranes, organelles, etc.), the structure of nanomaterials, and the structure of microorganisms (bacteria, viruses, etc.). Electron microscopes are widely used in many fields, including biology, materials science, chemistry, geology, and physics.
[0028] Electron microscopes include scanning electron microscopes (SEM), transmission electron microscopes (TEM), and scanning transmission electron microscopes (STEM).
[0029] The following section uses a scanning electron microscope as an example to introduce the structure and working principle of an electron microscope.
[0030] For example, Figure 1 A schematic diagram of a scanning electron microscope is shown.
[0031] like Figure 1As shown, a scanning electron microscope includes: an electron gun, a condenser lens, an objective lens, a deflection coil, a sample stage, a signal detector, a signal processing system, a display system, and a vacuum system.
[0032] An electron gun, consisting of a cathode, a grid, and an anode, is used to emit an electron beam.
[0033] A condenser lens is used to focus an electron beam to obtain a parallel light source.
[0034] A sample stage, also known as a mechanical stage, is used to place the sample to be observed.
[0035] Objective lens, used to focus an electron beam onto the sample surface.
[0036] A scanning coil is used to perform a grating-like scanning of the electron beam on the sample surface.
[0037] Signal detectors are used to collect signals such as secondary electrons.
[0038] A signal processing system is used to convert the signals collected by the signal detector into sample images.
[0039] A display system for displaying sample images.
[0040] Vacuum system, used to maintain the vacuum state of the sample stage and electron optics system.
[0041] Specifically, during the operation of a scanning electron microscope: an electron gun emits an electron beam, which is then focused onto the sample surface by an electromagnetic lens system (a lens system consisting of a condenser lens, objective lens, etc.) under the action of an accelerating voltage. Under the action of a deflection coil, the electron beam performs a grating scan on the sample. At the same time, a signal detector synchronously detects electrons and photons scattered from the sample surface after the interaction between the incident electrons and the sample. These are then amplified and processed by a signal processing system and finally imaged on a display system.
[0042] Understandable. Figure 1 The structure of the scanning electron microscope shown is only an example. In other embodiments, the scanning electron microscope may include more or fewer components than shown, such as aperture deflection coils, centering coils, astigmatism coils, etc. This application does not limit this.
[0043] Since the final image displayed on the electron microscope is generated based on the interaction between the electron beam and the sample, the interaction between different samples and electron beams emitted under the same conditions (e.g., the same accelerating voltage) may differ. Therefore, the quality of sample images obtained based on electron beams generated under the same conditions may vary. Alternatively, the interaction between different feature points of the same sample and electron beams emitted under the same conditions may also differ, and electron beams generated under the same conditions may not be able to accurately observe different features in the same sample.
[0044] Therefore, when using an electron microscope, it is usually necessary to adjust the working parameters of the electron microscope (such as accelerating voltage, working distance, etc.) to obtain higher quality (e.g., higher resolution) sample images or sample information in sample images.
[0045] However, since electron microscopes control the electron beam through electric and magnetic fields (such as accelerating voltage, electromagnetic lenses, etc.), changing the operating parameters of the electron microscope may change the related parameters controlling the electron beam (such as parameters related to the electric and magnetic fields controlling the electron beam), causing the electron beam to deflect. This may in turn cause the sample image to deflect. If the sample image deflection distance is too large, the sample image may be outside the field of view of the electron microscope, that is, the image displayed by the electron microscope display system does not include sample information.
[0046] It is cumbersome and time-consuming to manually adjust the sample image to be displayed in the center of the field of view by the user (the operator of the electron microscope) (e.g., moving the sample stage of the electron microscope or adjusting the electron beam offset data).
[0047] For example, current methods typically require users to identify feature points of a sample at low magnification using an electron microscope and record the positional relationship between these feature points and the target observation point. After changing the electron microscope's operating parameters, the identified feature points are then located again at low magnification, and the target observation point is found based on the recorded positional relationship between these feature points and the target observation point. This method is cumbersome and time-consuming, and it is also difficult to implement when there are no feature points near the target observation point.
[0048] To address the aforementioned issues, this application proposes a correction method. The method includes: acquiring target operating parameters and current operating parameters of an electron microscope; inputting the target operating parameters and current operating parameters into a first model and acquiring a first adjustment parameter output by the first model, wherein the first model is determined based on different operating parameters of the electron microscope and the electron beam shift data corresponding to those parameters; the first adjustment parameter is used to compensate for the electron beam shift data of the electron microscope after switching from the current operating parameters to the target operating parameters; switching the current operating parameters to the target operating parameters; and adjusting the electron microscope based on the first adjustment parameter.
[0049] It is understood that the calibration method provided in this application embodiment determines the adjustment parameters through a model, which can achieve more accurate calibration, and does not require manual operation by the user. It is simple and quick, reduces the calibration difficulty, and improves the calibration efficiency.
[0050] To better understand the technical methods of this application, the control methods provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0051] For example, Figure 2 A schematic diagram illustrating the implementation process of a correction method is shown in the embodiments of this application. It can be understood that... Figure 2 The execution entity in the flowchart shown is the electron microscope 100. For ease of description, the following will refer to... Figure 2 When describing the flowchart shown, the execution subject of the flowchart will not be repeated.
[0052] like Figure 2 As shown, this process includes, but is not limited to:
[0053] S201: Obtain the target operating parameters and current operating parameters of the electron microscope 100.
[0054] In some embodiments, a user may need to observe a specific region of the same sample under multiple conditions. For example, by setting different operating parameters of the electron microscope 100, sample images can be observed under different operating parameters.
[0055] In some embodiments, the operating parameters include, but are not limited to: accelerating voltage, operating distance, electromagnetic lens current, electrostatic field voltage, aperture deflection coil current, centering coil current, astigmatism coil current, etc.
[0056] S202: Input the target working parameters and the current working parameters into the first model, and obtain the first adjustment parameters output by the first model.
[0057] In some embodiments, the first model is determined based on different operating parameters of the electron microscope 100 and the electron beam offset data corresponding to the different operating parameters. The first adjustment parameter is used to compensate for the electron beam offset data of the electron microscope 100 after switching from the current operating parameter to the target operating parameter.
[0058] It is understandable that the first model could be an electro-optical model.
[0059] The electron beam offset data includes, but is not limited to: the offset vector of the electron beam in the preset coordinate system, the rotation angle of the electron beam in the preset coordinate system, and the relative relationship between the electron beam and the mechanical stage of the electron microscope 100.
[0060] Specifically, electron beam offset data corresponding to different operating parameters can be determined using any standard sample with identifiable characteristic morphology. For example, by changing the electromagnetic lens current to alter the electron beam path, the electron beam offset data, such as the offset vector and / or rotation angle, of a certain feature point of the standard sample relative to a preset fixed coordinate system (e.g., the mechanical stage coordinate system) can be calculated before and after changing the electromagnetic lens current. Figure 3 The coordinate diagram shown.
[0061] like Figure 3 As shown, the offset vector in the Z-axis direction can be determined based on the working distance of the electron beam focusing, the offset vector in the X-axis direction can be determined based on the movement of the mechanical stage or the movement of the electron beam, the offset vector in the Y-axis direction can be determined based on the movement of the mechanical stage or the movement of the electron beam, and the rotation angle in the R-axis direction can be determined based on the rotation angle (a) of the characteristic morphology (e.g., preset feature points) on the sample image of the acquired standard sample.
[0062] It is understandable that, since the offset vector and rotation angle of the electron microscope 100 under various operating parameters are regular, it is only necessary to collect the offset vector and rotation angle under certain specific operating parameters to calculate the offset vector and rotation angle under other operating parameters. There is no need for the user to manually adjust all operating parameters and for the electron microscope 100 to collect the offset vector and rotation angle under each operating parameter.
[0063] In some embodiments, the first adjustment parameter includes, but is not limited to: position, focal distance, astigmatism, and alignment.
[0064] Among these, position, or beam shift, refers to the degree to which the optical axis of the electron beam deviates from the central axis of the electron microscope during imaging. Focal length, or beamfocal length, refers to the distance from the optical center of the electromagnetic lens to the focal point. Astigmatism, or beamastigmatism of the electron beam, refers to the phenomenon where defects in the electron microscope's optical system (such as uneven magnetic field distribution in the lens system or inconsistent divergence angles of the electron beam) prevent the electron beam from forming a sharp circular focal point on the imaging plane, instead creating an elliptical or irregularly shaped spot. Alignment, or beam alignment, refers to aligning the optical axis of the electron beam, the center of the sample, and the central axis of the display system onto a straight line, ensuring that the electron beam accurately illuminates the central region of the sample and forms a clear image on the imaging plane.
[0065] It is understandable that the first adjustment parameter can be the difference between the various system parameters of the electron microscope 100 (such as position, focal distance, astigmatism, alignment, etc.) under the current working parameters and the target working parameters.
[0066] S203: Switch the current working parameters to the target working parameters and adjust the electron microscope based on the first adjustment parameter.
[0067] In some embodiments, after the electron microscope 100 determines the first adjustment parameter, the current operating parameter is switched to the target operating parameter, and the electron microscope is adjusted based on the first adjustment parameter.
[0068] Specifically, the electron microscope 100 adjusts the electron microscope based on a first adjustment parameter, including:
[0069] Corresponding to the first adjustment parameter being position, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the electron beam offset data of the electron microscope, and adjusting the movement data of the mechanical stage of the electron microscope.
[0070] Alternatively, corresponding to the first adjustment parameter being the focal length, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the movement data of the mechanical stage of the electron microscope, adjusting the current value of the magnetic coil of the electron microscope, and adjusting the voltage value of the electrostatic field of the electron microscope.
[0071] Alternatively, corresponding to the first adjustment parameter being astigmatism, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the current value of the magnetic coil of the electron microscope, adjusting the voltage value of the electrostatic field of the electron microscope.
[0072] Alternatively, corresponding to the first adjustment parameter being centering, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the current value of the magnetic coil of the electron microscope, adjusting the voltage value of the electrostatic field of the electron microscope.
[0073] Specifically, if nanoscale observation of the sample is required, corresponding to the first adjustment parameter being position, the electron microscope 100 is adjusted by jointly adjusting the electron beam offset data and the movement data of the mechanical stage. Specifically, this can be achieved by: performing micrometer-level movement based on the mechanical stage movement, and then performing the remaining correction based on the electron beam offset. In this way, the image quality degradation caused by excessive electron beam offset can be minimized, thereby improving the image quality of the sample.
[0074] It is understood that the correction method provided in this application embodiment determines the adjustment parameters through a model, enabling more accurate correction without requiring manual operation by the user. This method is simple, quick, reduces calibration difficulty, and improves calibration efficiency. Furthermore, the correction method provided in this application embodiment can reduce the probability of sample image shift.
[0075] Understandable. Figure 2 The method flow shown is only an exemplary illustration; in other embodiments, Figure 2 The process shown can also include more steps.
[0076] For example, in some other embodiments, after completing S203 (switching the current operating parameters to the target operating parameters and adjusting the electron microscope based on the first adjustment parameters), the electron microscope 100 further acquires a target image of the first sample based on the adjusted electron microscope 100 and the target operating parameters; compares the target image with a first image of the first sample corresponding to the current operating parameters; if the reference feature point in the first image is in the target image and the deviation between the position of the reference feature point in the first image and its position in the target image is greater than a preset deviation threshold, or if there is no reference feature point in the first image; adjusts the operating parameters of the electron microscope 100 and acquires a second image of the first sample after adjusting the operating parameters of the electron microscope; if the reference feature point in the first image is in the target image and the deviation between the position of the reference feature point in the first image and its position in the target image is less than or equal to a preset deviation threshold; and updates the first model based on the difference between the position of the reference feature point in the target image and the position of the reference feature point in the first image.
[0077] In other words, after the electron microscope 100 completes the calculation and compensation of the target working parameters, it acquires the sample image under the target working parameters (i.e., the target image) and compares it with the sample image under the current working parameters (i.e., the first image). The positional relationship of the defined reference feature points in the image determines whether the adjustment is completed.
[0078] For example, if the reference feature point in the first image is in the target image, and the deviation between the position of the reference feature point in the first image and its position in the target image is less than or equal to a preset deviation threshold, it indicates that the reference feature point is still within the observation field of the electron microscope 100. The adjustment of the electron microscope 100 is then completed, and the user can observe the first sample based on the target image. Furthermore, the first model is updated based on the difference between the positions of the reference feature point in the target image and the reference feature point in the first image, so that this difference in relative position can be considered when determining adjustment parameters using the first model next time. For example, this difference in relative position can be defined as an error caused by system aging or other reasons.
[0079] For example, if the reference feature point in the first image is in the target image, and the deviation between the position of the reference feature point in the first image and its position in the target image is greater than a preset deviation threshold, or if the reference feature point is not present in the first image, it indicates that the reference feature point is not in the field of view of the electron microscope 100, and the electron microscope 100 needs to be further adjusted. For example, the operating parameters of the electron microscope 100 can be adjusted (e.g., manually or automatically performing focusing, astigmatism correction, alignment, etc.), and a second image of the first sample can be obtained after adjusting the operating parameters of the electron microscope.
[0080] Furthermore, the second image is compared with the sample image (i.e., the first image) under the current working parameters, and the positional relationship of the defined reference feature points in the image is used to determine whether the adjustment has been completed.
[0081] For example, if a reference feature point in the first image is in the second image and the deviation between the position of the reference feature point in the first image and the position of the reference feature point in the second image is less than or equal to a preset deviation threshold, the first model is updated based on the difference between the position of the reference feature point in the second image and the position of the reference feature point in the first image.
[0082] For example, if a reference feature point in the first image is located in the second image, and the deviation between the position of the reference feature point in the first image and its position in the second image is greater than a preset deviation threshold, or if no reference feature point exists in the second image; switch the target working parameters to the current working parameters, reduce the magnification of the electron microscope, input the target working parameters and the current working parameters to the first model, and obtain the second adjustment parameters output by the first model, wherein the second adjustment parameters are used to compensate for the electron beam shift data of the electron microscope after switching from the current working parameters to the target working parameters; switch the current working parameters to the target working parameters, and adjust the electron microscope based on the second adjustment parameters.
[0083] In other words, after adjusting the working parameters of the electron microscope 100 (e.g., manually or automatically completing focusing, astigmatism correction, alignment, etc.), the adjusted sample image (i.e., the second image) is acquired and compared with the sample image under the current working parameters (i.e., the first image). The positional relationship of the defined reference feature points in the image determines whether the adjustment is complete.
[0084] For example, if a reference feature point in the first image is also present in the second image, and the deviation between the position of the reference feature point in the first image and its position in the second image is less than or equal to a preset deviation threshold, it indicates that the reference feature point is still within the observation field of the electron microscope 100. The adjustment of the electron microscope 100 is then complete, and the user can observe the first sample based on the second image. Furthermore, the first model is updated based on the difference between the positions of the reference feature point in the second image and the reference feature point in the first image, so that this difference in relative position can be considered when determining adjustment parameters using the first model next time.
[0085] For example, if a reference feature point in the first image is also present in the second image, and the deviation between the position of the reference feature point in the first image and its position in the second image is greater than a preset deviation threshold, or if the reference feature point is not present in the second image, it indicates that the reference feature point is not within the observation field of the electron microscope 100. This may be because the first model cannot compensate for the electron beam shift data at the current magnification, and the electron microscope 100 needs further adjustment. For example, the target operating parameter is switched to the current operating parameter, the magnification of the electron microscope is reduced, and the target operating parameter and the current operating parameter are input to the first model. The second adjustment parameter output by the first model is obtained, wherein the second adjustment parameter is used to compensate for the electron beam shift data of the electron microscope after switching from the current operating parameter to the target operating parameter; the current operating parameter is switched to the target operating parameter, and the electron microscope is adjusted based on the second adjustment parameter.
[0086] It is understood that the process of adjusting the electron microscope 100 based on the second adjustment parameter can refer to the description of the process of adjusting the electron microscope 100 based on the first adjustment parameter described above. Furthermore, after adjusting the electron microscope based on the second adjustment parameter, the adjusted sample image can be further compared with the first image to determine whether further adjustment is needed. That is, the adjustment process after completing the adjustment based on the first adjustment parameter is repeated until the condition is met (e.g., the reference feature point is in the field of view).
[0087] To more clearly explain the above adjustment process, the following will combine... Figure 4 The flowchart shown details the correction method provided in the embodiments of this application.
[0088] For example, Figure 4 An embodiment of this application illustrates a schematic flowchart of another correction method. It can be understood that... Figure 4 The execution entity in the flowchart shown is the electron microscope 100. For ease of description, the following will refer to... Figure 4 When describing the flowchart shown, the execution subject of the flowchart will not be repeated.
[0089] like Figure 4 As shown, this process includes, but is not limited to:
[0090] S401: Electron beam shift data under different operating parameters were measured using standard samples, and a first model was established.
[0091] In some embodiments, electron beam offset data corresponding to different operating parameters can be determined using any standard sample with identifiable characteristic morphology. For example, by changing the electromagnetic lens current to cause a change in the electron beam path, the electron beam offset data, such as offset vector and / or rotation angle, of the coordinate position of a certain feature point of the standard sample relative to a preset fixed coordinate system (e.g., the mechanical stage coordinate system) can be calculated before and after changing the electromagnetic lens current.
[0092] For details, please refer to the relevant description in S202 above, which will not be repeated here.
[0093] S402: Acquire the current operating parameters and first image of the electron microscope 100, and determine the reference feature points.
[0094] In some embodiments, the electron microscope 100 acquires the current operating parameters of the electron microscope 100 and reads the first image of the first sample under the current operating parameters.
[0095] For example, the electron microscope 100 can record the current values of each magnetic coil and the voltage values of each electrostatic field in the electron microscope 100 under the current state to determine the current operating parameters of the electron microscope 100. The electron microscope 100 can record the state of the mechanical stage to determine the coordinates of the first sample under the current operating parameters. The electron microscope 100 can record the characteristic image information of the first sample under the current operating parameters in the buffer as the first image.
[0096] In some embodiments, the electron microscope 100 acquires a preset deviation threshold. The deviation threshold may be distance data.
[0097] In other embodiments, the electron microscope 100 determines the target location corresponding to a reference feature point in the first image. The target location is a region within the field of view, which can be defined, for example, by marking within the field of view, or by the proportion of the target location to the center of the field of view; this application does not impose any limitations on this.
[0098] S403: Obtain target operating parameters.
[0099] In some embodiments, the electron microscope 100 acquires target operating parameters input by the user.
[0100] It is understandable that users can enter only the working parameters that need to be changed, or they can enter all the working parameters; this application does not impose any restrictions on this.
[0101] S404: Calculate the electron beam offset data before and after changing the working parameters using the first model, obtain the first adjustment parameter output by the first model, and adjust the electron microscope 100 based on the first adjustment parameter to compensate for the image defocusing caused by the electron beam offset generated in order to achieve the target working parameters.
[0102] In some embodiments, the electron microscope 100 inputs target operating parameters and current operating parameters to a first model, calculates electron beam offset data before and after changing the operating parameters using the first model, and obtains a first adjustment parameter output by the first model. Furthermore, the electron microscope 100 is adjusted based on the first adjustment parameter to compensate for image defocusing caused by electron beam offset in order to achieve the target operating parameters.
[0103] Specifically, the process of adjusting the electron microscope 100 based on the first adjustment parameter can be referred to the relevant description in S203 above, and will not be repeated here.
[0104] S405: Obtain the target image after changing the working parameters and compare it with the first image before changing the working parameters.
[0105] In some embodiments, after the electron microscope 100 has been adjusted based on the first adjustment parameter, the target image of the first sample is acquired based on the adjusted electron microscope 100 and the target working parameters.
[0106] S406: Determine whether the reference feature points in the target image meet the observation conditions.
[0107] In some embodiments, if the determination result is yes, then S407 is further executed to optimize the first model based on the relative position difference of reference feature points in the target image and the first image.
[0108] In other embodiments, if the determination result is negative, S408 is further executed to perform focusing, astigmatism correction, centering, and to acquire a second image, which is then compared with the first image before the change of operating parameters.
[0109] In some embodiments, the observation conditions may be: the reference feature point in the first image is in the target image, and the deviation between the position of the reference feature point in the first image and its position in the target image is less than or equal to a preset deviation threshold; or, the target position of the reference feature point in the target image is located within the field of view.
[0110] S407: Optimize the first model based on the relative position difference of reference feature points in the target image and the first image.
[0111] In some embodiments, if the reference feature points in the target image meet the observation conditions, the electron microscope 100 records the relative position difference between the reference feature points in the target image and the reference feature points in the first image into a database, and optimizes the first model based on the relative position difference, for example, defining the difference as an error caused by system aging.
[0112] S408: Performs focusing, astigmatism correction, centering, and acquires a second image, which is then compared with the first image before the operating parameters were changed.
[0113] In some embodiments, if the reference feature points in the target image do not meet the observation conditions, the electron microscope 100 performs a focusing, astigmatism correction, and centering operation, and acquires a second image of the first sample based on the adjusted electron microscope 100. Furthermore, the second image is compared with the first image before the operating parameters were changed.
[0114] It is understood that in other embodiments, the above-mentioned focusing, astigmatism correction, and centering operations can also be performed manually by the user, and this application does not impose any restrictions on this.
[0115] S409: Determine whether the reference feature points in the second image meet the observation conditions.
[0116] In some embodiments, if the determination result is yes, then S410 is further executed to optimize the first model based on the relative position difference of reference feature points in the second image and the first image.
[0117] In other embodiments, if the determination result is negative, S411 is further executed to switch back to the current target parameter and reduce the magnification.
[0118] In some embodiments, the observation conditions may be: the reference feature point in the first image is in the second image, and the deviation between the position of the reference feature point in the first image and the position in the second image is less than or equal to a preset deviation threshold; or, the target position of the reference feature point in the second image is located within the field of view.
[0119] S410: Optimize the first model based on the relative position difference of reference feature points in the second image and the first image.
[0120] In some embodiments, if the reference feature points in the second image meet the observation conditions, the electron microscope 100 records the relative position difference between the reference feature points in the second image and the reference feature points in the first image into a database, and optimizes the first model based on the relative position difference, for example, defining the difference as an error caused by system aging.
[0121] S411: Switch back to the current target parameters and reduce the magnification.
[0122] In some embodiments, if the reference feature points in the second image do not meet the observation conditions, it means that the reference feature points are not in the field of view of the electron microscope 100. This may be because the first model cannot complete the compensation of the electron beam offset data at the current magnification. The electron microscope 100 switches back to the current target parameters and reduces the magnification.
[0123] Furthermore, step S402 is executed to acquire the current operating parameters and first image of the electron microscope 100, and to determine reference feature points.
[0124] Understandable. Figure 4 The method flow shown is only an exemplary illustration; in other embodiments, Figure 4 The process shown may also include more or fewer steps, as described above. Figure 4 Some steps in the process can be merged or split, and this application does not impose any restrictions on this.
[0125] It is understood that the above description only uses scanning electron microscope as an example of electron microscope 100. In other embodiments, electron microscope can also be other types, such as dual-beam electron microscope with electron beam imaging function or multi-beam electron microscope with electron beam imaging function, or other electron microscopes with electron beam imaging function. This application does not limit the specific type of electron microscope 100.
[0126] The structure of the electron microscope 100 in the embodiments of this application is described below with reference to the accompanying drawings.
[0127] For example, Figure 5 A schematic diagram of the structure of an electron microscope 100 is shown according to an embodiment of this application.
[0128] like Figure 5 As shown, the electron microscope 100 may include a processor 110, a memory 120, an electron optical system 130, a vacuum system 140, a power supply system 150, a sample stage system 160, an imaging system 170, a control system 180, a cooling system 190, and auxiliary systems 191, etc.
[0129] It is understood that the structures illustrated in the embodiments of this application do not constitute a specific limitation on the electron microscope 100. In other embodiments of this application, the electron microscope 100 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.
[0130] Processor 110 may include one or more processing units, such as an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural network processing unit (NPU). Different processing units may be independent devices or integrated into one or more processors. Processor 110 can be used to execute the correction method provided in the embodiments of this application.
[0131] The processor 110 may also include a memory for storing instructions and data.
[0132] The memory 120 can be used to store computer-executable program code, including instructions. The memory 120 may include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a given function, etc. The data storage area may store data created during the use of the electron microscope 100 (such as operating parameters, sample images, etc.). Furthermore, the memory 120 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, universal flash storage (UFS), etc. The processor 110 implements the correction method provided in this application embodiment by executing instructions stored in the memory 120 and / or instructions stored in memory disposed within the processor 110.
[0133] Electron optical system 130 is used to generate, focus, and control an electron beam to achieve high-resolution imaging of a sample. Electron optical system 130 may include an electron gun, a condenser lens, an objective lens, and a scanning coil. Specifically, the electron gun, condenser lens, objective lens, and scanning coil can be referenced above. Figure 1 The relevant descriptions in the document are not repeated here.
[0134] The vacuum system 140 is used to maintain a high vacuum environment inside the electron microscope 100 to prevent the electron beam from colliding with air molecules, thereby ensuring the stability of the electron beam and the imaging quality.
[0135] The power supply system 150 provides a stable power supply to all components of the electron microscope 100, ensuring the normal operation of the electron microscope 100.
[0136] The sample stage system 160 is used to support and move a sample, enabling the sample to be scanned and imaged under an electron beam. The sample stage system 160 may include a sample stage, a sample moving device, a sample tilting device, and a sample rotating device. The sample stage is used to fix the sample. The sample moving device is used to move the sample in the X, Y, and Z directions. The sample tilting device is used to adjust the tilt angle of the sample. The sample rotating device is used to rotate the sample to achieve multi-angle observation.
[0137] Imaging system 170 is used to capture the signal after the electron beam interacts with the sample and convert it into an observable image. Imaging system 170 may include: a fluorescent screen, an electron detector, an image processing system, and a computer system. The fluorescent screen is used for direct image observation. The electron detector is used to capture electron signals; the electron detector includes, but is not limited to, scintillator detectors, secondary electron detectors, and backscattered electron detectors. The image processing system is used to process and analyze the acquired images, including magnification, contrast adjustment, and filtering. The computer system is used to store and process image data.
[0138] The control system 180 is used to operate and adjust the various components of the electron microscope 100 to achieve optimal imaging results. The control system 180 may include an operation panel, an automatic control system, and a software system. The operation panel is used to acquire parameters of the electron microscope 100 that are manually adjusted by the user. The automatic control system is used to automatically adjust the parameters of the electron microscope 100, such as autofocus and automatic correction. The software system is used to control the operation of the electron microscope 100, including parameter setting, image acquisition, and processing.
[0139] The cooling system 190 is used to keep the various components of the electron microscope 100 operating within the normal temperature range and to prevent overheating from affecting the imaging quality.
[0140] Auxiliary system 191 includes devices for specific experiments or functions, such as heating stages, freezing stages, stretching stages, and gas injection systems.
[0141] In some embodiments, this application also provides a computer-readable storage medium storing at least one computer program instruction, at least one program segment, code set, or instruction set, which is loaded and executed by a model training system to implement the correction method provided in the above-described method embodiments.
[0142] In some embodiments, this application also provides a computer program product, which includes computer program instructions that, when executed by a model training system, enable the device to implement the correction methods provided in the above-described method embodiments.
[0143] The various embodiments of the mechanisms disclosed in this application can be implemented in hardware, software, firmware, or a combination of these implementation methods. Embodiments of this application can be implemented as computer programs or program code executable on a programmable system, the programmable system including at least one processor, a storage system (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device.
[0144] Program code can be applied to input instructions to execute the functions described in this application and generate output information. The output information can be applied to one or more output devices in a known manner. For the purposes of this application, the processing system includes any system having a processor such as, for example, a digital signal processor (DSP), a microcontroller, an application-specific integrated circuit (ASIC), or a microprocessor.
[0145] The program code can be implemented using a high-level procedural language or an object-oriented programming language to communicate with the processing system. Assembly language or machine language can also be used when needed. In fact, the mechanisms described in this application are not limited to any particular programming language. In either case, the language can be a compiled language or an interpreted language.
[0146] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried on or stored thereon on one or more temporary or non-temporary machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. For example, the instructions may be distributed via a network or through other computer-readable media. Therefore, computer-readable media may include various media capable of storing program code, such as USB flash drives, external hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0147] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.
[0148] It should be noted that all units / modules mentioned in the device embodiments of this application are logical units / modules. Physically, a logical unit / module can be a physical unit / module, a part of a physical unit / module, or a combination of multiple physical units / modules. The physical implementation of these logical units / modules themselves is not the most important factor; the combination of functions implemented by these logical units / modules is the key to solving the technical problems proposed in this application. Furthermore, to highlight the innovative aspects of this application, the above-described device embodiments of this application have not introduced units / modules that are not closely related to solving the technical problems proposed in this application. This does not mean that the above-described device embodiments do not contain other units / modules.
[0149] It should be noted that in the examples and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.
[0150] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of this application.
Claims
1. A calibration method, characterized in that, Applied to an electron microscope, the method includes: Obtain the target operating parameters and current operating parameters of the electron microscope; The target operating parameters and the current operating parameters are input into the first model, and the first adjustment parameter output by the first model is obtained. The first model is determined based on different operating parameters of the electron microscope and the electron beam offset data corresponding to different operating parameters. The first adjustment parameter is used to compensate for the electron beam offset data of the electron microscope after switching from the current operating parameters to the target operating parameters. The current operating parameters are switched to the target operating parameters, and the electron microscope is adjusted based on the first adjustment parameters.
2. The method according to claim 1, characterized in that, The electron beam offset data includes at least one of the following: the offset vector of the electron beam in a preset coordinate system, the rotation angle of the electron beam in the preset coordinate system, and the relative relationship between the electron beam and the mechanical stage of the electron microscope.
3. The method according to claim 1 or 2, characterized in that, The first adjustment parameter includes at least one of the following: Position, focal length, astigmatism, centering.
4. The method according to claim 3, characterized in that, Corresponding to the first adjustment parameter being position, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the electron beam offset data of the electron microscope, adjusting the movement data of the mechanical stage of the electron microscope; or, Corresponding to the first adjustment parameter being focal length, adjusting the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the movement data of the electron microscope's mechanical stage, adjusting the current value of the electron microscope's magnetic coil, and adjusting the voltage value of the electron microscope's electrostatic field; or, Corresponding to the first adjustment parameter being astigmatism, the adjustment of the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the current value of the magnetic coil of the electron microscope, adjusting the voltage value of the electrostatic field of the electron microscope; or, Corresponding to the first adjustment parameter being aligned, the adjustment of the electron microscope based on the first adjustment parameter includes at least one of the following: adjusting the current value of the magnetic coil of the electron microscope, and adjusting the voltage value of the electrostatic field of the electron microscope.
5. The method according to any one of claims 1 to 4, characterized in that, Also includes: The target image of the first sample was obtained based on the adjusted electron microscope and target working parameters; The target image is compared with the first image of the first sample corresponding to the current working parameters; The reference feature point in the first image is in the target image, and the deviation between the position of the reference feature point in the first image and its position in the target image is greater than a preset deviation threshold, or the reference feature point does not exist in the first image; Adjust the operating parameters of the electron microscope and acquire a second image of the first sample after adjusting the operating parameters of the electron microscope; The reference feature point in the first image is in the second image, and the deviation between the position of the reference feature point in the first image and its position in the second image is less than or equal to the preset deviation threshold. The first model is updated based on the difference between the positions of the reference feature points in the second image and the positions of the reference feature points in the first image.
6. The method according to claim 5, characterized in that, Also includes: The reference feature point in the first image is in the second image, and the deviation between the position of the reference feature point in the first image and the position of the reference feature point in the second image is greater than the preset deviation threshold, or the reference feature point does not exist in the second image; The target working parameters are switched to the current working parameters, the magnification of the electron microscope is reduced, and the target working parameters and the current working parameters are input into the first model. The second adjustment parameter output by the first model is obtained, wherein the second adjustment parameter is used to compensate for the electron beam offset data of the electron microscope after switching from the current working parameters to the target working parameters. The current operating parameters are switched to the target operating parameters, and the electron microscope is adjusted based on the second adjustment parameters.
7. The method according to any one of claims 1 to 6, characterized in that, The operating parameters include at least one of the following: acceleration voltage, operating distance, electromagnetic lens current, electrostatic field voltage, aperture deflection coil current, centering coil current, and astigmatism coil current.
8. The method according to any one of claims 1 to 7, characterized in that, The type of electron microscope includes at least one of the following: scanning electron microscope, dual-beam electron microscope with electron beam imaging function, and multi-beam electron microscope with electron beam imaging function.
9. An electron microscope, characterized in that, include: Memory for storing instructions executed by one or more processors of the electron microscope, and A processor for performing the method according to any one of claims 1 to 8.
10. A computer-readable medium, characterized in that, The computer-readable medium stores instructions that, when executed on the electron microscope, cause the electron microscope to perform the method of any one of claims 1 to 8.
11. A program product, characterized in that, The program product includes instructions that, when executed on an electron microscope, cause the electron microscope to perform the method of any one of claims 1 to 8.