A method for preparing a single crystal microcolumn with a specific crystal direction in a polycrystalline material based on an SEM-FIB-EBSD integrated system
By using the SEM-FIB-EBSD integrated system, the problem of precise fabrication of single-crystal micropillars in polycrystalline materials was solved by utilizing the FIB high-current visualization of grain boundaries and combining it with EBSD characterization and gradient beam processing, thus improving the accuracy and reliability of the experiment.
Patent Information
- Application Number
- CN202610289965.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-11
- Publication Date
- 2026-05-29
AI Technical Summary
In polycrystalline materials, it is difficult to accurately locate a single grain region. The prepared micropillars often contain other grains or have grain boundary defects. Furthermore, there is a lack of effective methods for characterizing grain orientation, which leads to large errors in experimental results.
The SEM-FIB-EBSD integrated system was used to visualize grain boundaries by FIB high-current irradiation, combined with EBSD characterization to screen single-crystal regions, and single-crystal micropillars were fabricated by gradient current FIB processing.
Precise locking of single-crystal regions was achieved, improving the single-crystal purity and preparation success rate of micropillars, reducing surface damage, and enhancing the accuracy and reliability of experiments.
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Figure CN122109161A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of materials microscopic experiments, specifically a method for ensuring that the micropillars are single-crystal structures and determining their grain orientation during in-situ microscopic experimental preparation of single-crystal micropillars from polycrystalline materials. Background Technology
[0002] In in-situ microscopic experimental research in materials science, single-crystal micropillars, with their singular crystal structure, have become a key carrier for exploring core issues such as the intrinsic mechanical properties, deformation mechanisms, and failure patterns of materials. Whether studying the plastic deformation mechanism of metallic materials or analyzing the electrical properties of semiconductor materials, single-crystal micropillars can eliminate interference factors such as polycrystalline interfaces and grain mixing, providing the most direct intrinsic performance data for experiments.
[0003] However, traditional methods for preparing single-crystal micropillars in polycrystalline metallic materials face two major challenges. On the one hand, it is difficult to accurately pinpoint a single grain region in polycrystalline materials, and the prepared micropillars often contain other grains or have grain boundary defects, causing experimental results to fail to accurately reflect the intrinsic properties of the material. On the other hand, there is a lack of effective grain orientation characterization methods, so even if single-crystal micropillars are prepared, their crystallographic orientation cannot be accurately determined, resulting in significant errors in the subsequent correlation analysis between experimental data and material properties.
[0004] In existing technologies, some methods attempt to combine focused ion beam (FIB) and electron backscatter diffraction (EBSD) techniques, but they have shortcomings in terms of the synergy of the operational procedures and the precision of parameter control. For example, the correspondence between the regions characterized by EBSD and those processed by FIB is poor, making it difficult to ensure that the prepared region is the target single-crystal region. Furthermore, the lack of gradient optimization of FIB processing parameters can easily lead to surface damage or crystal structure destruction of the micropillars. These problems severely restrict the success rate of single-crystal micropillar fabrication and the reliability of experimental data, necessitating an integrated method for fabrication and characterization that is standardized in procedures, precise in parameters, and reliable in results. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings in the above-mentioned background technology and provide a method for preparing single crystal micropillars with specific crystal orientations in polycrystalline materials based on the SEM-FIB-EBSD integrated system, so as to improve the accuracy and reliability of in-situ microscopic experiments on materials.
[0006] The technical solution of this invention is: A method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on a SEM-FIB-EBSD integrated system includes the following steps: Step S1: Polish and grind the polycrystalline material sample and fix it on the sample stage of the SEM-FIB-EBSD integrated system; Step S2: Locate the target area using an SEM probe, and irradiate the target area with a high-current FIB beam to highlight the grain boundaries of multiple crystals within the target area; Step S3: Characterize the irradiated target area using an EBSD probe, and select the single crystal regions corresponding to the crystal orientation of interest based on the characterized grain orientation distribution map. Step S4: Based on the grain boundary shape of the single crystal region of interest in EBSD, the same grain boundary shape is found by comparison under the FIB probe, thereby locating the single crystal region, and the FIB beam current is adjusted in gradient to accurately irradiate and prepare single crystal micropillars.
[0007] The crystalline material sample includes metals, ceramics, or semiconductors; the SEM-FIB-EBSD integrated system includes a scanning electron microscope, a focused ion beam microscope, and an electron backscatter diffractometer.
[0008] In step S1, the geometric dimensions of the polycrystalline material sample are φ10*3mm.
[0009] In step S2, the accelerating voltage of the SEM probe is 10~20kV, the aperture is 30μm, and the magnification is 200~300X.
[0010] In step S2, during high-current irradiation, the working distance of the sample stage is 5.2 mm, the beam current of the FIB probe is 3 nA to 30 nA, the magnification is 500X to 600X, and the irradiation time is 5 to 8 minutes.
[0011] In step S3, the magnification of the EBSD probe is 500X~600X, the scanning parameters are set to an accelerating voltage of about 20kV, and the working distance is 17.5mm~18.5mm.
[0012] In step S4, the gradient adjustment of the FIB beam includes using a 30kV ion beam energy, first selecting a 15nA~30nA ion beam for coarse cutting, then selecting a 3nA ion beam for fine cutting, and finally selecting a 100pA or 50pA ion beam for fine cutting to obtain a single-crystal micropillar sample.
[0013] The beneficial effects of this invention are: 1. This invention achieves precise locking of single-crystal regions through synergistic screening of FIB high-current irradiation and EBSD characterization, ensuring the single-crystal purity of micropillars from the source and significantly improving the preparation success rate.
[0014] 2. This invention employs a gradient beam FIB processing method to avoid surface damage or crystal structure destruction of micropillars caused by single beam processing, thus ensuring the dimensional accuracy and structural integrity of the micropillars.
[0015] 3. The entire process of this invention is completed based on the SEM-FIB-EBSD integrated system. In-situ operation reduces contamination and damage during sample transfer, resulting in higher experimental efficiency and more reliable results. It is applicable to a variety of polycrystalline material systems. Attached Figure Description
[0016] Some specific embodiments of the present invention will now be described in detail by way of example and not limitation, with reference to the accompanying drawings.
[0017] Figure 1 This is a flowchart of the present invention. Figure 2 This is a schematic diagram of a groove or depression in the FIB field of view.
[0018] Figure 3 This is a schematic diagram of the FIB irradiated area under a low-magnification SEM view.
[0019] Figure 4a This is a schematic diagram of the EBSD characterization results for the target region.
[0020] Figure 4b This is a schematic diagram of the target area under FIB irradiation.
[0021] Figure 5 This is a schematic diagram of a single-crystal micropillar under SEM view. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0023] This invention utilizes SEM, FIB, and EBSD technologies in synergy to achieve the fabrication and crystal orientation characterization of single-crystal micropillars in polycrystalline materials. Scanning electron microscopy (SEM) provides high-resolution imaging capabilities, clearly revealing the microstructure of materials. Focused ion beam microscopy (FIB) uses a high-energy ion beam to bombard the sample, achieving atomic-level etching, deposition, or cutting. Electron backscatter diffraction (EBSD) can identify phase composition, measure grain size and shape, and simultaneously determine crystal orientation information and analyze grain arrangement patterns and texture types by detecting the backscattered electron diffraction patterns on the sample surface.
[0024] like Figure 1 As shown, a method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on an integrated system [wzh3] [4] includes the following steps: Step S1. Pretreatment of polycrystalline material samples 1) Grinding and polishing Polycrystalline material samples were polished to ensure their surface condition met the requirements for EBSD characterization.
[0025] Polycrystalline material samples include, but are not limited to, polycrystalline system materials such as metals, ceramics, and semiconductors, and are suitable for various microscopic experiments on polycrystalline materials that require the investigation of intrinsic properties.
[0026] The geometric dimensions of the polycrystalline material sample are φ10*3mm. This size needs to be adapted to the space limitations of the sample stage of the SEM-FIB-EBSD integrated system. This is to avoid the inability to fit the sample stage due to the size being too large, and to prevent the subsequent fixation from being unstable or the processing area from being too small.
[0027] 2) Fixed The polished polycrystalline material sample was fixed onto the sample stage of the SEM-FIB-EBSD integrated system using conductive tape. During fixation, the surface of the pseudo-polycrystalline material sample was placed upwards, ensuring that the surface was flat and without tilt.
[0028] The SEM-FIB-EBSD integrated system is existing equipment, including a scanning electron microscope, a focused ion beam microscope, and an electron backscatter diffractometer. The scanning electron microscope is a Zeiss field emission scanning electron microscope, the focused ion beam microscope uses Bruker's [wzh5] technology, and the electron backscatter diffractometer uses Oxford's EBSD technology.
[0029] Step S2. Irradiate the target area with a high-current beam. 1) Locate the target area Turn on the SEM probe, set the accelerating voltage to 10~20kV, the aperture to 30μm, the magnification to 200~300X, and the working distance of the sample stage to 15mm. Use the SEM probe to find the target area of the polycrystalline material sample at a relatively low magnification.
[0030] Because of the polishing process, the target area cannot display any grain boundary features under the SEM probe at this time.
[0031] 2) Focus on the target area Turn on the FIB probe and set the ion beam energy to 15kV~30kV and the beam current to 50pA~100pA.
[0032] Tilt the sample stage at 54° and adjust the working distance of the sample stage to 5.2mm. Only at this distance can the target area be clearly focused by both the FIB probe and the SEM probe at the same time.
[0033] 3) High-current irradiation target area Increase the beam current of the FIB probe to 3nA~30nA, focus it, and increase the magnification to 500X~600X. Irradiate the target area on the surface of the polycrystalline material sample for 5~8 minutes until the grain boundaries of the target area are clearly visible.
[0034] Long-term high-current FIB irradiation induces differences in irradiation response between grain boundaries and the interior of grains, ultimately making grain boundaries more prominent in morphology or contrast. The specific mechanism is as follows: within the ordered atomic arrangement of grains, energy transfer from ion collisions is more efficient, and sputtering yield (the number of atoms removed per unit ion bombardment) is relatively stable; at grain boundaries, atomic bonding is weak and the arrangement is disordered, making atomic detachment more likely during ion bombardment, resulting in higher sputtering yield. Over time, this accumulation leads to the formation of microgrooves or depressions at grain boundaries, thus highlighting them in morphology or contrast. Figure 2 As shown, grooves or depressions are visible at the grain boundaries of polycrystalline material samples subjected to long-term irradiation under FIB field of view.
[0035] Switching to the SEM probe and reducing the magnification to 180X reveals that the target area, due to prolonged irradiation by the high-current FIB beam, exhibits significantly lighter contrast than its surrounding areas. For example... Figure 3 As shown, the areas with lighter contrast (yellow dashed boxes) are the FIB irradiated areas under low-magnification SEM field of view.
[0036] Step S3. Screening single-crystal regions 1) Focus on the target area Turn on the EBSD probe, tilt the sample stage to 70°, and simultaneously adjust the working distance of the sample stage to 18mm. Only at this distance can the target area (the area with shallow contrast after long-term irradiation by high-current FIB) be clearly focused by both the SEM probe and the EBSD probe.
[0037] 2) Characterize the target region Set the EBSD probe magnification to 500X~600X (consistent with the magnification during FIB irradiation), set appropriate scanning parameters for EBSD characterization, and obtain the grain orientation distribution map of the target region after FIB irradiation based on the EBSD characterization results (e.g., Figure 4a As shown in the figure, determine the single crystal region A containing the crystal orientation of interest in the grain orientation distribution diagram.
[0038] Characterization parameter settings include: acceleration voltage set to 20kV, and working distance set to 17.5mm~18.5mm.
[0039] Step S4. Preparation of single-crystal micropillars 1) Select a single crystal region Return the sample stage tilt angle to 54°, turn on the FIB probe, and then move the working distance of the sample stage back to 5.2 mm. Set the FIB ion beam energy to 15kV~30kV and the beam current to 50pA~100pA. Under the FIB probe, locate the single crystal region A containing the crystal orientation of interest by observing the grain boundary shape (e.g., Figure 4b (As shown).
[0040] 2) Gradient beam processing of single-crystal micropillars Based on the target micropillar size, the FIB beam is precisely irradiated by gradient adjustment. First, a large beam is used for rough cutting and shaping, then a medium beam is used for fine dimensional refining, and finally a small beam is used for fine processing to prepare a single-crystal micropillar.
[0041] The specific fabrication steps for single-crystal micropillars are as follows: In single-crystal region A, using a 30kV ion beam energy, a coarse cut of a micropillar with a relatively large diameter (approximately 7.8~8.2μm) and a depth of 3.5μm is first performed using an ion beam current of 15nA~30nA. Then, a 3nA ion beam current is used to finely cut the micropillar to a diameter of 2.4μm~2.6μm and a depth of 3.9μm. Finally, an ion beam current of 100pA or 50pA is used to finely cut the micropillar to a depth of 1.9μm~2.1μm and a depth of 4μm, resulting in a single-crystal micropillar (e.g., ...). Figure 5 As shown in the figure, this ensures that the micropillar crystal structure is not damaged.
[0042] [9]
[10] The advantage of this invention is that the SEM probe of the integrated system can always be turned on, but the EBSD and FIB probes cannot be turned on at the same time. It is very difficult to find the same target grain in a polycrystalline metal sample under the EBSD and FIB probes. The above method adjusts the FIB irradiation time and intensity to make the grain boundaries of the grains in the irradiation area stand out, without significantly damaging the sample surface. The contrast of the target area after irradiation will be significantly shallower than that of the surrounding areas under the SEM probe. At this time, the FIB probe is turned off and the EBSD probe is turned on. The height and angle of the EBSD probe are adjusted, and the target area is focused by finding the area with shallow contrast through the SEM probe. The crystal orientation of multiple grains in the target area is characterized by the EBSD probe. The crystal orientation distribution map obtained by EBSD characterization can clearly show the grain orientation and grain boundary shape of these grains. By comparing the grain boundary shape, grains with the same grain boundary shape can be found under the FIB probe. The above method solves the problem of accurately locking a specific grain area in polycrystalline metal materials by linking the EBSD probe and the FIB probe.
[0043] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.
[0044] Figure 1 Should "preparation of positioning region A for single-crystal micropillars" be changed to "preparation of micropillars in single-crystal region A"? Edited Is this the existing system? If there are any improvements, please provide specific solutions. It is a pre-developed integrated system device Is "probe" the appropriate word here? Change to range Change to range Change to range The attached images show the key processes. Those who have operated similar equipment will understand, while those who haven't used this equipment may find it difficult to explain.
[0045] Since neither the FIB nor the SEM probe extends in this way, it is uniformly changed to "open" here.
Claims
1. A method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on a SEM-FIB-EBSD integrated system, comprising the following steps: Step S1: Polish and grind the polycrystalline material sample and fix it on the sample stage of the SEM-FIB-EBSD integrated system; Step S2: Locate the target area using an SEM probe, irradiate the target area with a high-current FIB beam to highlight the grain boundaries of multiple crystals within the target area, and then use an SEM probe to verify the contrast difference between the target area and the surrounding area after irradiation. Step S3: Characterize the irradiated target area using an EBSD probe. Based on the grain orientation and grain boundary shape distribution map of the target area after characterization, select the single crystal regions corresponding to the crystal orientation of interest. Step S4: Based on the grain boundary shape of the single crystal region of interest in EBSD, the same grain boundary shape in the target region is found by comparison under the FIB probe, thereby locating the single crystal region, and the FIB beam current is adjusted in a gradient to accurately prepare single crystal micropillars with specific crystal orientation in polycrystalline metal samples.
2. The method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on the SEM-FIB-EBSD integrated system according to claim 1, characterized in that: The crystalline material sample includes metals, ceramics, or semiconductors; the SEM-FIB-EBSD integrated system includes a scanning electron microscope, a focused ion beam microscope, and an electron backscatter diffractometer.
3. The method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on the SEM-FIB-EBSD integrated system according to claim 2, characterized in that: In step S1, the geometric dimensions of the polycrystalline material sample are φ10*3mm.
4. The method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on the SEM-FIB-EBSD integrated system according to claim 1, characterized in that: In step S2, the accelerating voltage of the SEM probe is 10~20kV, the aperture is 30μm, and the magnification is 200~300X.
5. The method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on the SEM-FIB-EBSD integrated system according to claim 4, characterized in that: In step S2, during high-current irradiation, the working distance of the sample stage is 5.2 mm, the beam current of the FIB probe is 3 nA to 30 nA, the magnification is 500X to 600X, and the irradiation time is 5 to 8 minutes.
6. The method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on the SEM-FIB-EBSD integrated system according to claim 1, characterized in that: In step S3, the magnification of the EBSD probe is 500X~600X, the characterization parameters are set to an accelerating voltage of about 20kV, and the working distance is 17.5mm~18.5mm.
7. The method for preparing single-crystal micropillars with specific crystal orientations in polycrystalline materials based on the SEM-FIB-EBSD integrated system according to claim 1, characterized in that: In step S4, the gradient adjustment of the FIB beam includes using a 30kV ion beam energy, first selecting a 15nA~30nA ion beam for coarse cutting, then selecting a 3nA ion beam for fine cutting, and finally selecting a 100pA or 50pA ion beam for fine cutting to obtain a single-crystal micropillar sample.