Composition mapping and energy dispersive x-ray spectroscopy techniques for imaging with variable charged particle beam parameters

Abstract

The disclosure relates to compositional mapping and energy dispersive X-ray spectroscopy techniques for imaging with variable charged particle beam parameters. A method of mapping compositional variations within a sample includes: acquiring an electron backscatter image of a surface of the sample using a first set of electron beam parameters; identifying, from the electron backscatter image, a plurality of locations of regions or points on the sample to be analyzed by energy dispersive X-ray spectroscopy (EDS); acquiring an EDS spectrum from each of the identified positions or points using a second set of electron beam parameters different from the first set of electron beam parameters; and generating a compositional change map on the sample from the plurality of EDS spectra.

Description

Technical Field

[0001] This application relates to charged particle beam microscopes and charged particle beam microscopy techniques. More specifically, this application relates to systems and methods for imaging and compositional mapping of a sample using variable beam parameters of an incident charged particle beam.

[0002] Incorporation by Reference

[0003] All patents, patent application publications, and other published documents mentioned herein are incorporated herein by reference in their entirety as if fully set forth herein. Background Art

[0004] Many biological and chemical analysis techniques, as well as chemical analysis techniques, require obtaining spatially resolved data related to the area or volume distribution of various structures, molecules, and / or elements within one or more samples. To collect such data, a chemical analysis device can be closely paired with an imaging device. For example, in medical science, the distribution of special color or fluorescent tags within a tissue sample can be used to identify specific proteins, diseased tissue, gene expression regions, cell structures, etc. The study of such distributions can utilize optical detectors, including cameras interfaced with an optical microscope or an electron microscope. In the semiconductor industry, an electron microscope can be used to collect impurity distributions or structural deviations within a wafer or a device carrier layer. In the mining industry, the distribution of elements within minerals or various minerals can be studied by detecting characteristic X-rays emitted from the surface of a rock sample when the sample is studied under an electron microscope. In some cases, the sample can be a fine particle sample composed of many separate sand or silt particles that do not adhere to each other. Generally, the sample to be analyzed can be any flat surface of any material. For example, in some other cases, the sample can include a polished flat surface of a semiconductor device layer or a rock sample. In many cases, individual particles or rock samples can be embedded in an encapsulant such as epoxy resin.

[0005] In many cases, the sample prepared for microscope analysis is much larger than the field of view of the microscope used to image the sample. Therefore, the first important step in data acquisition is to accurately understand the overall structure of the sample under investigation, including finding and locating various regions or structures of interest according to sample coordinates, and recording these coordinates for future research and visualization after data acquisition. A software product, known as Thermo Scientific TM Maps TM software, not only helps with the first step, but also with subsequent data collection and data analysis steps. During data collection, the Maps TM software can automatically acquire a series of tiled images to create a complete overview of the sample. The Maps TMThe software can also automatically stitch together the resulting images to form a single overview image. Once acquired, the individual images and tile sets can be overlaid on top of each other and organized in an editable multi-layered structure. Each layer can be selectively hidden, shown, transparently overlaid, and aligned with other images or layers. The user can freely zoom and pan to browse the acquired data and make annotations. The area enclosed by the tile set can be as large as the travel range of the sample platform. The software can be used to acquire and analyze data from any type of microscope (such as optical microscopes, scanning electron microscopes, transmission electron microscopes, focused ion beam microscopes, etc.). Finally, the software can also combine and compare images of a single sample obtained from different detectors or systems, for example, sample images obtained from backscattered electrons and secondary electron imaging emissions or X-ray excited emissions.

[0006] Energy-dispersive X-ray spectroscopy (EDS, EDX, EDXS or XEDS) is an analytical technique that is particularly suitable for elemental mapping of samples within an electron microscope. In such an analysis, characteristic X-ray emissions from the sample are detected while an electron beam is directed onto the sample through the electron microscope column of a scanning electron microscope (SEM), transmission electron microscope (TEM) or scanning transmission electron microscope (STEM). Upon excitation by the electron beam, each of the multiple elements within the sample emits a corresponding characteristic X-ray emission spectrum. The X-ray spectral signals from each such element can be separated from one another and recorded as a function of position on the sample (e.g., as a set of images, such as the tiled and / or layered images described above).

[0007] Maps TM A useful feature of the software is its ability to automatically perform a second data collection instance on the surface of the sample based on an analysis of the results of a previous first data collection instance. This feature is useful for compositional mapping because during such mapping, after the first stage of image data collection, there can be an analysis of the image data, and then based on that analysis, subsequent stages of compositional data collection can be planned and executed. The intervention analysis can include automatically segmenting the image into individual particles and / or grains by automatically identifying particle boundaries and / or grain boundaries, and the image can be an overview image constructed from the registration of several acquired images. Once the image is segmented, the software can control the sample platform and / or the scanable incident beam to interrogate selected points within each identified sample particle or grain. As an example, initial imaging can be performed by detecting backscattered electrons emitted from the sample within an electron microscope by a first detector, and subsequent compositional data collection can be performed by energy-dispersive X-ray spectroscopy using a second detector within the same microscope.

[0008] Unfortunately, currently available compositional mapping algorithms belonging to electron microscope-based EDS analysis do not provide varying electron beam voltages during data acquisition. Thus, the entire data acquisition session encompassing both the detection of backscattered electrons for imaging and the detection of emitted X-rays for chemical analysis must share the same electron beam setting (e.g., beam energy controlled by beam acceleration voltage). In order to obtain sufficient X-ray signal intensity at each sampling position on the sample, it is necessary to utilize a uniform high beam acceleration voltage. However, the present inventors have found that such conditions may result in less than ideal imaging of backscattered electrons from particulate samples. This problem occurs because when using a high beam voltage, the penetration of electrons into the sample often creates a large "depth of field", which results in the resulting images often showing blurred images with "out-of-focus" grain boundaries. The blurring is an artifact of the larger electron interaction volume at high beam voltages, which causes surface features to be blurred by subsurface features.

[0009] Figure 1 is a flowchart of a known algorithm workflow for generating a compositional map of a sample. In a first step (step 101), a backscattered electron (BSE) image of the sample is acquired. This image may consist of only a single image frame (i.e., the platform holding the sample is not moved during image acquisition), or may be a composite image generated by aligning and subsequently overlaying and / or merging multiple image frames. In the next step (step 103), background signals (if present) attributable to the sample mountant (e.g., epoxy resin) are removed from the acquired backscattered electron signals that make up the image. In step 105, the background-corrected image is automatically analyzed to identify spatially separated particles (if any) in the sample carrier and to determine the boundary and platform coordinates of these particles. In step 107, the background-corrected image is further automatically analyzed to identify individual particles within the sample and to determine the boundary position coordinates of these particles, with reference to a sample-based and / or laboratory-based reference coordinate system. Finally, in step 109, one or more sampling positions are selected within each of the multiple identified grains, and EDS compositional analysis is obtained at each such position by measuring the energy spectrum of the X-rays emitted from each sampling position during the guidance of the electron beam to the corresponding sampling position.

[0010] Since for generating compositional maps ( Figure 1) The known algorithm workflow does not provide electron beam adjustment. Therefore, during the acquisition of backscattered electron images (step 101) and EDS composition analysis (step 109), the same electron beam parameters (e.g., beam current and beam energy, the latter being controlled by the beam acceleration voltage) must be used. Unfortunately, the inventors have found that the beam parameters that are optimal for obtaining an acceptable backscattered electron image are not optimal for obtaining an X-ray spectrum, and vice versa. If the beam parameters are initially set to values selected to produce an acceptable X-ray spectrum within a reasonable data acquisition time (e.g., a beam current of 5 nA and a beam acceleration voltage of 20 keV to 30 keV), then due to electron penetration beneath the surface of the grains, the grain boundaries in the backscattered electron image will be unclear. Poor imaging results in uncertainty in selecting the most representative locations for subsequent composition analysis. As a practical example, a "reasonable" X-ray spectrum analysis rate corresponds to obtaining a complete set of X-ray spectra at each analyzed surface location (i.e., point) from a circular sample with a diameter of 30 mm within a time period of no more than two hours, where the surface locations are spaced within a Cartesian grid with a grid spacing of 10 μm. This corresponds to a spectrum collection rate of no less than approximately 110 spectra per second. To enable each such X-ray spectrum to have acceptable signal-to-noise ratio characteristics, each X-ray spectrum should correspond to the detection of approximately 1000 X-ray photons per millisecond. The collection area of the X-ray detector linearly affects the collection speed; for this task, a detector with a collection area of approximately 100 mm 2 is preferred.

[0011] Figure 2 is a backscattered electron image that exemplifies a typical example of the problems that occur when the same beam voltage used for X-ray analysis is also used for BSE imaging of the same sample. Specifically, the edges of particles 201 and 202 and the intergranular boundary between grains 202a and 202b of particle 202 are not well-defined. On the other hand, if the electron beam is adjusted such that the edges of the particles and grains become well-defined, additional analysis time is required to obtain a noise-free X-ray spectrum, thereby reducing the overall analysis efficiency. Therefore, there is a need in the art for an imaging and composition mapping technique that maintains accuracy and efficiency. Summary of the Invention

[0012] According to a first aspect of the present disclosure, a method of mapping compositional variations within a sample includes: obtaining an electron microscope image of a surface of the sample using a first set of electron beam parameters; identifying a plurality of locations of regions or points on the sample to be analyzed by energy dispersive X-ray spectroscopy (EDS) from the electron backscatter image; obtaining an EDS spectrum from each of the identified locations or points using a second set of electron beam parameters different from the first set of electron beam parameters; and generating a compositional variation map on the sample from the plurality of EDS spectra. Generally, the electron microscope image is obtained by backscattered electron (BSE) imaging using a scanning electron microscope (SEM). However, if the sample includes a thin sheet having a thickness less than about 200 nm or less than about 100 nm depending on the type of the sample (possibly thinned by ion beam milling), the electron microscope image can be obtained by transmission electron microscopy using a transmission electron microscope (TEM).

[0013] According to a second aspect of the present disclosure, an electron microscope system includes: (a) an electron source and an electron optical column; (b) a sample stage located within a vacuum chamber for supporting a sample of the specimen; (c) a first detector for detecting electrons backscattered and emitted from the sample when the electron beam impinges on the sample; (d) a second detector for detecting X-rays emitted from the sample when the electron beam impinges on the sample; and (e) one or more computer processors including executable instructions that, when executed by the one or more computer processors, cause the one or more computer processors to: (i) cause the first detector to obtain an electron microscope image of a surface of the sample using a first set of electron beam parameters; (ii) cause the second detector to obtain an EDS spectrum from each of a plurality of locations or points identified from the electron microscope image on the sample surface, wherein obtaining the plurality of EDS spectra uses a second set of electron beam parameters different from the first set of electron beam parameters; and (iii) generate a compositional variation map on the sample from the plurality of EDS spectra. Generally, the electron microscope image is obtained by backscattered electron (BSE) imaging using a scanning electron microscope (SEM). However, if the sample includes a thin sheet having a thickness less than about 200 nm or less than about 100 nm depending on the type of the sample (possibly thinned by ion beam milling), the electron microscope image can be obtained by transmission electron microscopy using a transmission electron microscope (TEM). BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and each other aspect of the present invention will become apparent from the following description, which is given by way of example only and with reference to the drawings, which are not necessarily drawn to scale, in which:

[0015] Figure 1 is a flowchart of a known algorithm workflow for generating a compositional map of a sample;

[0016] Figure 2 is an electron micrograph of a sample that includes a plurality of particles having a plurality of grains, the electron micrograph being obtained using an electron beam voltage that is selected according to Figure 1 the known algorithm workflow shown;

[0017] Figure 3 is a schematic diagram of an embodiment of a charged particle beam microscope system that can be used in conjunction with the method of the present disclosure;

[0018] Figure 4 is a flowchart of an algorithm workflow for generating a compositional map of a sample according to the present teachings; and

[0019] Figure 5 is the obtained Figure 2 electron micrograph of the sample, wherein the electron beam voltage is selected according to the algorithm workflow of the present teachings. DETAILED DESCRIPTION

[0020] The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the described embodiments will be readily apparent to those skilled in the art, and the general principles herein may be applied to other embodiments. Thus, the invention is not intended to be limited to the embodiments shown and examples, but is to be accorded the widest scope consistent with the features and principles shown and described. For a more complete understanding of the features of the present invention in detail, please refer to Figures 1 to 4 .

[0021] In the description of the present invention herein, it should be understood that unless otherwise implicitly or explicitly understood or stated, words in the singular form encompass their plural counterparts, and words in the plural form encompass their singular counterparts. Additionally, it should be understood that unless otherwise implicitly or explicitly understood or stated, for any given component or embodiment described herein, any possible candidates or alternatives listed for that component can generally be used individually or in combination with each other. Further, it should be understood that the drawings shown herein are not necessarily drawn to scale, where only some elements may be drawn for the clarity of the present invention. And, reference numerals may be repeated in the various drawings to indicate corresponding or similar elements. Additionally, it should be understood that unless otherwise implicitly or explicitly understood or stated, any list of candidates or alternatives is merely illustrative and not restrictive.

[0022] Unless otherwise defined, all other technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. It should be understood that there is an implied "about" prior to any quantitative term mentioned in this description, such that minor and non-substantive deviations are within the scope of the present invention. Whenever the terms "substantially", "about", "approximately" or similar statements are explicitly used in conjunction with a specific value, a variation of up to and including 10% of that value is reasonable unless otherwise explicitly stated. Additionally, the use of "comprising", "containing" and "including" is not intended to be limiting. As used herein, "a" may also refer to "at least one" or "one or more". Further, the use of "or" is inclusive such that the phrase "A or B" is true when A is true, B is true, or both A and B are true.

[0023] Figure 3 is a highly schematic illustration of an embodiment of a charged particle beam microscope system that can be used in conjunction with the methods of the present disclosure. More specifically, Figure 1 depicts an embodiment of a scanning electron microscope (SEM) 1. The microscope 1 includes an electron optical column 3 that generates a charged particle beam 5 (in this case, an electron beam) that propagates along a particle optical axis 5'. The electron optical column 3 is mounted within a vacuum chamber 7 that includes a sample carrier 9 for holding and / or positioning a sample 13 and an associated platform / actuator 11. The vacuum chamber 7 is evacuated using a vacuum pump (not shown). By means of a voltage source (not shown), the sample carrier 9 or at least the sample 13 can be biased (floated) to a potential relative to ground, if necessary.

[0024] The particle optical column 3 includes an electron source 17 (such as a Schottky emitter), electrostatic and / or magnetic lenses 19, 21 for focusing the electron beam 5 onto the sample 13 (generally, the structure is more complex than the schematic depiction herein), and a deflection unit 23 (shown schematically) for performing beam deflection / scanning of the beam 5. When the beam 5 impinges on or scans across the sample 13, the beam will cause emissions of various types of "stimulated" emissions (such as backscattered or secondary electron emissions) and / or radiation (such as emissions of X-rays and / or cathodoluminescence (infrared, visible, and / or ultraviolet photons)). One or more detectors can then be used to sense / record one or more of these radiation types, which can generally be used to form an image, spectrum, diffraction pattern, etc. by assembling a "map" (or "matrix") of the detector output as a function of the scanning position on the sample. Figure 1Two such detectors 25, 27 are shown. According to various embodiments of the present disclosure, detector 25 may be an X-ray detector (such as an SDD or Si(Li) sensor), and detector 27 may be a detector for backscattered electrons emitted from sample 13 in response to the impact of electron beam 5 on the sample. Detector 27 may be a segmented electron detector that includes a plurality of independent detection segments (e.g., quadrants) disposed around a central orifice 29 that permits electron beam 5 to pass through. These are merely examples, and those skilled in the art will understand that other detector types, numbers, and geometries / configurations are possible.

[0025] The electron microscopy system 1 further includes a controller / computer processing unit 31 that is configured to control, inter alia, lenses 19 and 21, deflection unit 23, and detectors 25, 27, and to display information collected from detectors 25, 27 on a display unit 33 (such as a flat panel display). This control is effected via control lines (bus) 31’. Controller 31 (or another controller) may additionally be used to perform various mathematical processes such as combining, integrating, subtracting, false coloring, edge enhancement, and other processes known to those skilled in the art. Additionally, an automatic identification process (e.g., for particle analysis or grain analysis) may be included in such processes.

[0026] Figure 1 Also depicted is a vacuum port 7’ that may be opened to introduce an article (component, sample) into the interior of vacuum chamber 7 and / or remove it from the interior of the vacuum chamber, or on which an auxiliary device or module (not depicted) may be mounted, for example. If desired, microscope 1 may include a plurality of such ports 7’.

[0027] Figure 4 is a flowchart of an algorithmic workflow method 400 for generating a compositional map of a sample using an electron microscope in accordance with the present teachings. In a first step of method 400 (step 401), the beam parameters of the electron beam incident on the sample are set to values suitable for electron microscope imaging (such as backscattered electron (BSE) imaging). In step 401, these electron beam parameters, which include the electron beam acceleration voltage and, in some embodiments, may include the beam current, may be automatically set to predetermined values. According to some embodiments, the beam parameters to be set in step 401 and subsequently used for imaging may be input by the user based on prior experience with a sample that includes materials, provenance, and / or preparation methods similar to the sample being analyzed. Generally, the beam parameters are selected and set so as to obtain an image having clear, well-defined image features (such as features corresponding to particle boundaries and / or grain boundaries).

[0028] In step 403 of method 400, an electron microscope image (such as a backscattered electron image) is acquired using the electron beam parameters set in step 401. The image may include only a single image frame (i.e., the stage holding the sample does not move during image acquisition). Alternatively, the image may be a composite image generated by aligning and then overlaying and / or merging a plurality of image frames obtained from a series of individual image frames corresponding to respective positions on the surface of the sample. According to the present invention, the electron beam parameters selected in step 401 and then used during the execution of step 403 generally include a beam acceleration voltage less than or equal to about 2 keV.

[0029] The next three steps (steps 405, 407, and 409) are substantially the same as steps 103, 105, and 107 outlined in Figure 1 In step 405, background signals attributable to the sample encapsulant (e.g., epoxy resin), if present, are removed from the acquired backscattered electron signals that make up the image. In step 407, the background-corrected image is analyzed to identify spatially separated particles (if any) in the carrier of the sample and to determine the boundaries and stage coordinates of these particles. In step 409, the background-corrected image may be further analyzed to identify and determine the boundaries of individual grains within the sample and to determine the stage coordinates of such grains. If the sample image is small or consists of few particles or grains, the user may manually identify the boundaries, particles, and grains visually on the graphical user interface depiction of the BSE image by pointing to the visually observable particles / grains or drawing lines around these particles / grains using a pointing device (e.g., a computer mouse). The software can then automatically convert the user input into the actual stage coordinates of the identified features on the actual surface of the sample. Alternatively, especially in the case of a large and / or complex sample image, well-known digital edge detection techniques based on discontinuities in image brightness may be used to automatically determine the boundaries of grains and / or particles.

[0030] The accuracy of the identification of the particle boundaries and / or grain boundaries identified in steps 407 and 409 depends on the clarity of the electron backscattered image generated in step 403. For example, Figure 5 is Figure 2 an image of the same sample region depicted in Figure 2 but with the electron beam parameters set, as in step 401 of method 400, to values that optimize the image clarity of the surface features. As described above, the beam parameters used in step 401 preferably include a beam acceleration voltage less than or equal to about 2 keV. Compared with Figure 5The improved image clarity and feature resolution reduce the uncertainty of the boundaries of particles 201 and 202, provide additional details related to the exposure of grains 202b at the surface of the sample, and allow the identification of surface cracks on particle 201. In addition, the enhanced contrast variation of particle 201 reveals energy bands that can indicate local compositional partitioning. Thus, for the purpose of subsequent compositional analysis, the boundaries between the energy bands can be classified as additional grain boundaries.

[0031] Step 409 also includes selecting locations on the surface of the sample that will subsequently be analyzed by energy-dispersive X-ray spectroscopy (EDS). The number of such EDS analyses and the specific locations on the sample for the analyses can be selected, with the goal of obtaining a representative compositional analysis while achieving the desired resolution of compositional variations in the least amount of time. Thus, the number and locations of the analyses depend on the size of the sample as well as the structural complexity and possible compositional complexity of the sample. The structural complexity of the sample can be estimated based on observed particle boundaries, grain boundaries, and / or striation boundaries.

[0032] Return to Figure 4Discussion of method 400 outlined above, step 411 includes changing the electron beam parameter values (from the values previously set in step 403) to a second set of values different from the first set of values, and this second set of values is suitable for EDS compositional analysis. Generally, the beam parameter values for EDS analysis can be selected so as to obtain sufficient signal intensity at each analysis point, and this signal intensity is necessary to achieve the desired compositional resolution on the sample in the least amount of time. If the sample is vulnerable to damage by the electron beam, further consideration should be given during selection to obtaining low-noise results without damaging the sample. Finally, in step 413, EDS compositional analysis is obtained at each such position by measuring the energy spectrum of the X-rays emitted from each sampling position during guiding the electron beam to the corresponding sampling position. The EDS compositional analysis can include one or more operations of scanning the electron beam over the surface of the sample and / or translating the sample platform one or more times to expose various regions of the sample surface to the electron beam. Generally, the electron beam parameters selected in step 411 and subsequently used during the execution of step 413 include a beam acceleration voltage greater than the beam acceleration voltage used during the execution of step 401 previously, so as to induce X-ray signals from most of the elements of interest. The rule of thumb is that during EDS analysis, the beam acceleration voltage must be approximately twice (i.e., 2x) the binding energy of the element of interest in order to obtain an available amount of X-rays from the atoms of that element. Most of the elements generally of interest have X-ray emission lines in the range of 0 keV to 5 keV, regardless of whether the emission is due to backfilling of inner shell orbits (e.g., elements O, Na, and Mg) or outer shell orbits of high atomic number elements (e.g., Au, Pt, U). However, since there are many overlapping X-ray emission lines in the energy range of 0 keV to 5 keV, analysts usually utilize a higher voltage (e.g., 25 keV) to excite the emission of multiple X-ray lines from transition metal elements with a larger atomic number in order to resolve the blurred peaks. As an example, both S and Pb show X-ray emission lines at 2.3 kV, but Pb also shows another line near 10 kV; thus, resolving Pb from S usually requires the simultaneous presence of both emission lines in order to accurately separate them. Similar to the above 2x voltage rule of thumb, these element identification problems mean that, in order to obtain the best results, most EDS work should be carried out using an electron beam acceleration voltage of 20 keV or higher. Therefore, according to a preferred embodiment of the present invention, during the execution of step 413, an acceleration voltage of 20 keV to 30 keV is used.

[0033] Although the present invention has been described in terms of the illustrated embodiments, it should be readily apparent to those of ordinary skill in the art that the embodiments can have variations and these variations should be within the scope of the present invention. Therefore, many such modifications can be made by those of ordinary skill in the art without departing from the scope of the appended claims.

Claims

1. A method for mapping compositional changes within a sample, the method comprising: acquiring an electron backscattered image of a surface of the sample using a first set of electron beam parameters; identifying from the electron backscatter image a plurality of locations of regions or points on the sample to be analyzed by energy dispersive X-ray spectroscopy (EDS); acquiring an EDS spectrum from each of the identified locations or points using a second set of electron beam parameters different from the first set of electron beam parameters; as well as A composition variation map across the sample is generated from the plurality of EDS spectra.

2. The method according to claim 1, wherein: The first set of electron beam parameters is selected to optimize the sharpness and spatial resolution of the electron backscatter image; and The second set of electron beam parameters is selected to achieve a desired compositional resolution.

3. The method of claim 1 or claim 2, wherein said identifying said plurality of locations or regions comprises automatically identifying particle boundaries or grain boundaries by digital image analysis.

4. The method according to claim 1 or claim 2, wherein: The first set of electron beam parameters includes using an electron beam accelerating voltage less than or equal to 2 keV; and The second set of electron beam parameters includes using an electron beam accelerating voltage in a range of 20 keV to 30 keV.

5. An electron microscope system, comprising: Electron source and electron optical column; A sample platform, the sample platform is located in the vacuum chamber and is used to support a sample of the sample; a first detector for detecting electrons backscattered from the sample when the electron beam impinges on the sample; a second detector for detecting X-rays emitted from the sample when the electron beam impinges on the sample; as well as One or more computer processors, the one or more computer processors comprising executable instructions that, when executed by the one or more computer processors, cause the one or more computer processors to: causing the first detector to acquire an electron backscatter image of the surface of the sample using a first set of electron beam parameters; causing the second detector to acquire an EDS spectrum from each of a plurality of locations or points on the sample surface identified from the electron backscatter image, wherein acquiring the plurality of EDS spectra uses a second set of electron beam parameters that are different from the first set of electron beam parameters; and A composition variation map across the sample is generated from the plurality of EDS spectra.

6. The electron microscope system of claim 5, wherein the executable instructions, when executed by the one or more computer processors, further cause the one or more computer processors to: causing the electron source and the electron optical column to set the first set of electron beam parameters to values ​​that optimize the sharpness and spatial resolution of the electron backscatter image; and The electron source and the electron optical column are caused to set the second set of electron beam parameters to values ​​that achieve a desired compositional resolution.

7. The electron microscope system of claim 5 or claim 6, wherein the executable instructions, when executed by the one or more computer processors, further cause the one or more computer processors to: Particle boundaries or grain boundaries within the sample are identified by digital image analysis of the electron backscattered image.

8. The electron microscope system of claim 5 or claim 6, wherein the executable instructions, when executed by the one or more computer processors, cause the one or more computer processors to: setting the electron beam acceleration voltage of the first set of electron beam parameters to a value less than or equal to 2 keV; and The electron beam acceleration voltage of the second set of electron beam parameters is set to a value within a range of 20 keV to 30 keV.

9. One or more computer-readable media having executable instructions defined therein, which when executed by one or more computer processors cause the one or more computer processors to: causing a first detector of the electron microscope system to acquire an electron backscatter image of a surface of the sample using a first set of electron beam parameters; identifying from the electron backscatter image a plurality of locations of regions or points on the sample that are subsequently analyzed by the electron microscope system using energy dispersive X-ray spectroscopy (EDS); causing a second detector of the electron microscope system to acquire an EDS spectrum from each of the identified locations or points using a second set of electron beam parameters different from the first set of electron beam parameters; and A composition variation map across the sample is generated from the plurality of EDS spectra.

10. The one or more computer-readable media of claim 9, wherein the executable instructions, when executed by the one or more computer processors, further cause the one or more computer processors to: causing the electron source and electron optical column of the electron microscope to set the first set of electron beam parameters to values ​​that optimize the sharpness and spatial resolution of the electron backscatter image; and The electron source and electron optical column are caused to set the second set of electron beam parameters to values ​​to obtain sufficient EDS signal intensity from each identified position or point, which is necessary to achieve the desired compositional resolution in the shortest time.

11. One or more computer-readable media according to claim 9 or claim 10, wherein the executable instructions, when executed by the one or more computer processors, further cause the one or more computer processors to: Particle boundaries or grain boundaries within the sample are identified by digital image analysis of the electron backscattered image.

12. One or more computer-readable media according to claim 9 or claim 10, wherein the executable instructions, when executed by the one or more computer processors, further cause the one or more computer processors to: setting the electron beam acceleration voltage of the first set of electron beam parameters to a value less than or equal to 2 keV; and The electron beam acceleration voltage of the second set of electron beam parameters is set to a value within a range of 20 keV to 30 keV.

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