WO2024087395A1 - 扫描电子显微镜的扫描方法及扫描电子显微镜 - Google Patents

扫描电子显微镜的扫描方法及扫描电子显微镜 Download PDF

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Publication number
WO2024087395A1
WO2024087395A1 PCT/CN2023/070548 CN2023070548W WO2024087395A1 WO 2024087395 A1 WO2024087395 A1 WO 2024087395A1 CN 2023070548 W CN2023070548 W CN 2023070548W WO 2024087395 A1 WO2024087395 A1 WO 2024087395A1
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Prior art keywords
scanning
interlaced
detection image
scans
target sample
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PCT/CN2023/070548
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English (en)
French (fr)
Inventor
陈航卫
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长鑫存储技术有限公司
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Publication of WO2024087395A1 publication Critical patent/WO2024087395A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B15/00—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
    • H01J37/147—Arrangements for directing or deflecting the discharge along a desired path
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
    • H01J37/28—Electron or ion microscopes; Electron or ion diffraction tubes with scanning beams

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  • the present disclosure relates to the technical field of integrated circuit detection, and in particular to a scanning method of a scanning electron microscope and a scanning electron microscope that executes the scanning method.
  • the Critical Dimension Scanning Electron Microscope is a scanning electron microscope that determines the boundaries of graphics based on the grayscale of the image and then calculates the line width of the graphics in the integrated circuit.
  • CDSEM Critical Dimension Scanning Electron Microscope
  • a high-energy electron beam is emitted to the sample (integrated circuit) under test in a scanning form, and the electron beam reflected from the surface of the sample under test is received.
  • a scanned image of the sample under test is formed based on the density of the reflected electron beam to obtain the microscopic morphology of the sample under test, thereby achieving further measurement of the target area in the sample under test, such as measuring the line width of the graphics.
  • CDSEM divides the scanning area into multiple scanning lines according to the set step size, scans the sample under test, and then forms a detection image of the sample under test by fitting the number of electrons in the electron beam reflected by each line of the sample under test received by the detector.
  • the detection image formed by CDSEM usually has problems such as uneven imaging brightness and uneven imaging clarity caused by reasons other than the sample. When testing microscopic areas, this unevenness will cause errors in the detection results.
  • the purpose of the present disclosure is to provide a scanning method of a scanning electron microscope and a scanning electron microscope, which are used to overcome, at least to a certain extent, the problem of uneven imaging clarity in a detection image formed by a CDSEM due to non-sample reasons.
  • a scanning method for a scanning electron microscope which is performed by a scanning electron microscope, wherein the scanning electron microscope comprises a first detector and a second detector arranged opposite to each other, and the scanning method comprises: performing multiple interlaced scans on a target sample in a first direction and a second direction to form a detection image of the target sample according to electron beams received by the first detector and the second detector; wherein the rows corresponding to two adjacent interlaced scans are different, the multiple interlaced scans correspond to all rows of the target sample, and each row of the target sample corresponds to at least two interlaced scans, and the at least two interlaced scans at least include scanning the row in the first direction and scanning the row in the second direction, and the second direction is the opposite direction of the first direction.
  • performing multiple interlaced scans on the target sample in a first direction and a second direction to form a detection image of the target sample according to the electron beams received by the first detector and the second detector includes: performing a first group of multiple interlaced scans on the target sample along the first direction to form a first detection image according to the electron beams received by the first detector, the rows corresponding to each of the interlaced scans in the first group of multiple interlaced scans are different, and the first group of multiple interlaced scans correspond to all the rows of the target sample; performing a second group of multiple interlaced scans on the target sample along the second direction to form a second detection image according to the electron beams received by the second detector, the rows corresponding to each of the interlaced scans in the second group of multiple interlaced scans are different, and the second group of multiple interlaced scans correspond to all the rows of the target sample; generating a detection image of the target sample according to the first detection image and the second detection image.
  • the order of scanning lines of the first group of multiple interlaced scans is the same as the order of scanning lines of the second group of multiple interlaced scans.
  • a scanning line sequence of the first group of multiple interlaced scans is different from a scanning line sequence of the second group of multiple interlaced scans.
  • the first group of multiple interlaced scans includes two interlaced scans, and the scanning line order is that the first interlaced scan corresponds to odd lines, and the second interlaced scan corresponds to even lines;
  • the second group of multiple interlaced scans includes two interlaced scans, and the scanning line order is that the third interlaced scan corresponds to even lines, and the fourth interlaced scan corresponds to odd lines.
  • the multiple interlaced scans of the target sample in the first direction and the second direction to form a detection image of the target sample according to the electron beams received by the first detector and the second detector also include: after forming the second detection image, performing a third group of multiple interlaced scans of the target sample along the second direction to form a third detection image; and performing a fourth group of multiple interlaced scans of the target sample along the first direction to form a fourth detection image.
  • generating the detection image of the target sample based on the first detection image and the second detection image includes: generating the detection image of the target sample based on the first detection image, the second detection image, the third detection image, and the fourth detection image.
  • the scanning line sequence corresponding to the third group of multiple interlaced scans is different from the scanning line sequence corresponding to the second group of multiple interlaced scans
  • the scanning line sequence corresponding to the fourth group of multiple interlaced scans is different from the scanning line sequence corresponding to the third group of multiple interlaced scans.
  • the first group of multiple interlaced scans includes two interlaced scans, and the scanning line order is that the first interlaced scan corresponds to odd lines, and the second interlaced scan corresponds to even lines;
  • the second group of multiple interlaced scans includes two interlaced scans, and the scanning line order is that the third interlaced scan corresponds to even lines, and the fourth interlaced scan corresponds to odd lines;
  • the third group of multiple interlaced scans includes two interlaced scans, and the scanning line order is that the fifth interlaced scan corresponds to odd lines, and the sixth interlaced scan corresponds to even lines;
  • the fourth group of multiple interlaced scans includes two interlaced scans, and the scanning line order is that the seventh interlaced scan corresponds to even lines, and the eighth interlaced scan corresponds to odd lines.
  • one interlaced scan corresponds to one scanning direction
  • two adjacent interlaced scans correspond to opposite scanning directions.
  • the target sample is scanned multiple times in the first direction and the second direction to form a detection image of the target sample according to the electron beams received by the first detector and the second detector, including: scanning the odd rows in the first direction in the first interlaced scan to generate a first sub-detection image according to the received information of the first detector; scanning the even rows in the second direction in the second interlaced scan to generate a second sub-detection image according to the received information of the second detector; scanning the odd rows in the second direction in the third interlaced scan to generate a third sub-detection image according to the received information of the second detector; scanning the even rows in the first direction in the fourth interlaced scan to generate a fourth sub-detection image according to the received information of the first detector; and generating a detection image of the target sample according to the first sub-detection image, the second sub-detection image, the third sub-detection image, and the fourth sub-detection image
  • one interlaced scan corresponds to a plurality of target rows, and in one interlaced scan, the scanning directions corresponding to adjacent target rows are opposite.
  • the scanning directions corresponding to two adjacent interlaced scans are set in the same order.
  • the scanning directions corresponding to two adjacent interlaced scans are set in opposite orders.
  • a scanning electron microscope comprising: a lens barrel, arranged along a vertical axis, for emitting an electron beam along the vertical axis; an electron deflector, arranged around the vertical axis, located below the lens barrel, for controlling the deflection of the electron beam emitted by the lens barrel according to a control signal; a sample stage, arranged below the electron deflector along the vertical axis, arranged horizontally, for horizontally carrying a target sample so that the target sample receives the deflected electron beam; a first detector and a second detector, relatively arranged between the sample stage and the electron deflector along the vertical axis, for receiving the electron beam reflected by the target sample; a controller, connected to the lens barrel, the electron deflector, the first detector and the second detector, for executing the scanning method as described in any one of the above items, controlling the lens barrel to emit the electron beam, sending the control signal to the electron deflector to control the deflection of the electron beam
  • the disclosed embodiment can solve the problem of uneven imaging clarity caused by differences in scanning order and scanning direction by setting up two detectors in opposite directions and scanning the target sample in two directions; and can solve the problem of uneven imaging brightness caused by the flow of electrons in adjacent rows caused by progressive scanning by performing interlaced scanning on the target sample, thereby greatly optimizing the imaging clarity of the CDSEM detection image and improving the detection accuracy of the target sample.
  • FIG. 1 is a schematic structural diagram of a scanning electron microscope in an exemplary embodiment of the present disclosure.
  • FIG. 2 is a flow chart of a scanning method of a scanning electron microscope provided in an embodiment of the present disclosure.
  • FIG. 3 is a flow chart of a scanning method in one embodiment of the present disclosure.
  • FIG. 4 is a flow chart of a scanning method in another embodiment of the present disclosure.
  • FIG. 5 is a schematic diagram of a scanning method in the embodiment shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of a scanning method according to an embodiment of the present disclosure.
  • FIG. 7 is a schematic diagram of a scanning method in yet another embodiment of the present disclosure.
  • FIG. 8 is a schematic diagram of a scanning method in one embodiment of the present disclosure.
  • Fig. 1 is a schematic diagram of the structure of a scanning electron microscope in an exemplary embodiment of the present disclosure.
  • the scanning electron microscope 100 shown in Fig. 1 can be used to perform the scanning method provided in the embodiment of the present disclosure.
  • a scanning electron microscope 100 may include:
  • a lens barrel 1 is arranged along a vertical axis and is used to emit an electron beam along the vertical axis;
  • the electron deflector 2 is arranged around the vertical axis and is located below the lens barrel 1, and is used to control the deflection of the electron beam emitted by the lens barrel 1 according to the control signal;
  • the sample stage 3 is arranged below the electron deflector 2 along a vertical axis and is arranged horizontally, and is used to horizontally carry the target sample 10 so that the target sample 10 receives the deflected electron beam;
  • the first detector 4 and the second detector 5 are arranged along a vertical axis between the sample stage 3 and the electron deflector 2 to receive the electron beam reflected by the target sample 10;
  • the controller 6 is connected to the lens barrel 1, the electron deflector 2, the first detector 4 and the second detector 5, and is used to execute the scanning method provided later in the embodiment of the present disclosure, control the lens barrel 1 to emit an electron beam, send a control signal to the electron deflector 2 for deflection, and receive the electron beams received by the first detector 4 and the second detector 5 to generate a detection image of the target sample 10.
  • the scanning electron microscope 100 shown in FIG1 may be a scanning electron microscope for feature size measurement, i.e., CDSEM.
  • the target sample 10 may be an integrated circuit to be tested, such as a wafer, a chip, etc., wherein the wafer may be a semi-finished wafer after a certain process of coating photoresist and exposing and developing the photoresist is completed.
  • the scanning electron microscope 100 is used to scan the defects of the exposed and developed photoresist in the target sample 10.
  • the controller 6 is used to output a first control signal to the electron deflector 2, so as to control the electron beam emitted by the lens barrel 1 through the electronic deflector 2 to gradually change from being deflected toward the first side in the horizontal direction to being deflected toward the second side in the horizontal direction, so as to achieve a line scan of the target sample; or, the controller 6 is used to output a second control signal to the electron deflector 2, so as to control the electron beam emitted by the lens barrel 1 through the electronic deflector 2 to gradually change from being deflected toward the second side in the horizontal direction to being deflected toward the first side in the horizontal direction, so as to achieve a line scan of the target sample.
  • the horizontal direction refers to a direction in a plane parallel to the loading surface of the sample stage 3.
  • the first detector 4 is arranged on the second side in the horizontal direction, and the second detector 5 is arranged on the first side in the horizontal direction; or, the first detector 4 is arranged on the first side in the horizontal direction, and the second detector 5 is arranged on the second side in the horizontal direction.
  • the deflection of the lens barrel 1 from the first side in the horizontal direction to the second side in the horizontal direction to achieve a row scan of the target sample is defined as scanning the target sample 10 along the first direction
  • the deflection of the lens barrel 1 from the second side in the horizontal direction to the first side in the horizontal direction to achieve a row scan of the target sample is defined as scanning the target sample 10 along the second direction.
  • the second direction is the opposite direction of the first direction
  • the first direction is the opposite direction of the second direction.
  • the scanning electron microscope 100 may further include a motion mechanism 7, which connects the sample stage 3 and the controller 6 and is used to drive the sample stage 3 to move in accordance with a motion signal sent by the controller 6 and in coordination with the deflection of the electron beam to achieve a line scan of the target sample.
  • a motion mechanism 7 which connects the sample stage 3 and the controller 6 and is used to drive the sample stage 3 to move in accordance with a motion signal sent by the controller 6 and in coordination with the deflection of the electron beam to achieve a line scan of the target sample.
  • the controller 6 is used to output a third control signal to the electron deflector 2 to control the electron beam to deflect toward the first side in the horizontal direction, and at the same time output a first motion signal to the motion mechanism 7 to control the sample stage 3 to move from the second side in the horizontal direction to the first side in the horizontal direction, so as to realize scanning of the target sample 10 from the first side in the horizontal direction to the second side in the horizontal direction, that is, scanning a row of the target sample 10 in the first direction.
  • the controller 6 outputs a fourth control signal to the electron deflector 2 to control the electron beam to deflect to the second side in the horizontal direction, and at the same time outputs a second motion signal to the motion mechanism 7 to control the sample stage 3 to move from the first side in the horizontal direction to the second side in the horizontal direction, so as to realize scanning of a row of the target sample 10 in the second direction.
  • the motion mechanism 7 may be provided or not.
  • the electron beam may not be deflected and the sample stage 3 may be moved, thereby realizing the relative movement of the electron beam and the target sample 10 in the first direction or the second direction, that is, realizing the scanning of the target sample 10 in the first direction or the scanning in the second direction.
  • the deflection of the electron beam may be controlled by controlling the electron deflector 2, thereby realizing the relative movement of the electron beam and the target sample 10 in the first direction or the second direction, that is, realizing the scanning of the target sample 10 in the first direction or the scanning in the second direction.
  • the control process described above is uniformly referred to as “scanning the target sample in the first direction/the second direction” in the subsequent embodiments of the present disclosure to simplify the description.
  • Fig. 2 is a flow chart of a scanning method of a scanning electron microscope provided by an embodiment of the present disclosure. The scanning method shown in Fig. 2 is performed by the scanning electron microscope shown in Fig. 1 .
  • a scanning method 200 may include:
  • the target sample is scanned multiple times in an interlaced manner in a first direction and a second direction to form a detection image of the target sample according to the electron beams received by the first detector and the second detector.
  • the rows corresponding to two adjacent interlaced scans are different, multiple interlaced scans correspond to all rows of the target sample, each row of the target sample corresponds to at least two interlaced scans, and the at least two interlaced scans at least include scanning the row in a first direction and scanning the row in a second direction, and the second direction is the opposite direction of the first direction.
  • the existing scanning method of the scanning electron microscope is to scan the target sample from top to bottom in a left-to-right scanning mode.
  • the sub-detection image generated by a complete scan from top to bottom can be marked as Frame*1.
  • the detection image of the target sample formed by combining multiple scanning results can be marked as Frame*4, Frame*8, or Frame*16, where 4, 8, and 16 are the numbers of sub-detection images generated.
  • the reason why the detection images of existing scanning electron microscopes have uneven imaging and uneven brightness is that the first scanned area is bombarded by the electron beam, resulting in electron reflection, which will leave holes, causing the electrons in the adjacent unscanned area to flow to the hole part of the first scanned area, causing the electron reflection amount of the later scanned area to be significantly reduced relative to the electron reflection amount of the first scanned area.
  • the regional brightness of the detection image is marked according to the electron reflection amount of different areas, the brightness of the first scanned area is higher than that of the later scanned area, resulting in uneven imaging brightness.
  • the hardware detection device in the existing scanning electron microscope is set on one side of the machine, the reflected electrons on the other side are consumed due to distance during the deflection process. Therefore, the image fitting results obtained based on the electron reflection amount are different up and down and left and right, which ultimately leads to inaccurate measurement results.
  • the scanning electron microscope is first improved, that is, two detectors in opposite directions are set to scan the target sample from two opposite directions, overcome the electron loss caused by the different exit angles and incident angles entering the detector and the different electron reflection distances of the reflected electrons, and repair the problem of uneven imaging clarity.
  • the target sample is set to be scanned in an interlaced manner, giving the unscanned area adjacent to the first scanned area a suitable electron recovery time, overcome the reduction in the amount of electron reflection in the later scanned area caused by the carrier coupling between adjacent areas, that is, solve the problem of uneven number of electrons reflected by the electron beam on the surface of the object and uneven imaging brightness.
  • FIG. 3 is a flowchart of a scanning method 200 according to an embodiment of the present disclosure.
  • a scanning method 200 may include:
  • Step S31 performing a first group of multiple interlaced scans on the target sample along a first direction to form a first detection image according to the electron beam received by the first detector, wherein the rows corresponding to each interlaced scan in the first group of multiple interlaced scans are different, and the first group of multiple interlaced scans correspond to all rows of the target sample;
  • Step S32 performing a second set of multiple interlaced scans on the target sample along the second direction to form a second detection image according to the electron beam received by the second detector, wherein each interlaced scan in the second set of multiple interlaced scans corresponds to different rows, and the second set of multiple interlaced scans corresponds to all rows of the target sample;
  • Step S33 generating a detection image of the target sample according to the first detection image and the second detection image.
  • the target sample is scanned in two directions successively, and finally a detection image of the target sample is jointly generated based on the scanning detection image along the first direction (first detection image) and the scanning detection image along the second direction (second detection image).
  • each row of the target sample 10 in the scanning in the first direction, is scanned along the first direction, and the reflected electron beam is received by the first detector 4.
  • each row of the target sample 10 is scanned along the second direction, and the reflected electron beam is received by the second detector 5.
  • each interlaced scan can generate a sub-detection image (i.e., the Frame mentioned above).
  • Interlaced scanning means that the rows of two scans are not adjacent.
  • one interlaced scan corresponds to multiple target rows, and there is at least one row between adjacent target rows.
  • one interlaced scan can correspond to the 1st, 3rd, 5th, 7th, 9th...rows of the target sample, or to the 2nd, 4th, 6th, 8th, 10th...rows; when there are two rows between the target rows, one interlaced scan can correspond to the 1st, 4th, 7th, 10th...rows, or to the 2nd, 5th, 8th, 11th...rows, or to the 3rd, 6th, 9th, 12th...rows. And so on, no further details are given.
  • a group of interlaced scans corresponds to at least two interlaced scans (for example, two interlaced scans with the starting scanning rows being the 1st row and the 2nd row respectively) to achieve scanning of all the rows of the target sample;
  • a group of interlaced scans corresponds to at least three interlaced scans (for example, three interlaced scans with the starting scanning rows being the 1st row, the 2nd row and the 3rd row respectively) to achieve scanning of all the rows of the target sample.
  • the above scanning order can be referred to as a scanning line order.
  • the scanning line order of the first group of multiple interlaced scans is the same as the scanning line order of the second group of multiple interlaced scans, or the scanning line order of the first group of multiple interlaced scans is different from the scanning line order of the second group of multiple interlaced scans.
  • the first group of multiple interlaced scans includes two interlaced scans, and the scanning line sequence is that the first interlaced scan corresponds to odd lines (for example, lines 1, 3, 5, 7, 9...), and the second interlaced scan corresponds to even lines (for example, lines 2, 4, 6, 8, 10...); the second group of multiple interlaced scans includes two interlaced scans, and the scanning line sequence is also that the first interlaced scan corresponds to odd lines, and the second interlaced scan corresponds to even lines.
  • the first group of multiple interlaced scans generates 2 frames of sub-detection images through two interlaced scans
  • the second group of multiple interlaced scans also generates 2 frames of sub-detection images through two interlaced scans, generating a total of 4 frames of sub-detection images, namely Frame*4.
  • the detection image of the target sample is generated based on the 4 frames of sub-detection images.
  • the first group of multiple interlaced scans includes two interlaced scans, and the scanning line sequence is that the first interlaced scan corresponds to odd lines (for example, lines 1, 3, 5, 7, 9...), and the second interlaced scan corresponds to even lines (for example, lines 2, 4, 6, 8, 10...); the second group of multiple interlaced scans includes two interlaced scans, and the scanning line sequence is that the first interlaced scan corresponds to even lines, and the second interlaced scan corresponds to odd lines.
  • the first group of multiple interlaced scans generates 2 frames of sub-detection images through two interlaced scans
  • the second group of multiple interlaced scans also generates 2 frames of sub-detection images through two interlaced scans, generating a total of 4 frames of sub-detection images, namely Frame*4.
  • a detection image of the target sample is generated based on the 4 frames of sub-detection images.
  • interlaced scanning in the process of forming the first frame sub-detection image, even if electron transfer (carrier neutralization) occurs between adjacent rows, it will not affect the uniformity of the scanning effect of two adjacent target rows separated by at least one row, and the brightness of the sub-detection image formed by the first group of first interlaced scanning is uniform. After a frame of sub-detection images is formed, the target rows corresponding to the first group of first interlaced scanning all become scanned rows.
  • the number of electrons in each target row (unscanned row) corresponding to the first group of second scanning is similar (because the relative position relationship between each target row and the scanned row is the same), and the brightness of the second frame sub-detection image formed by the first group of second interlaced scanning is uniform.
  • the brightness of the first detection image generated by fitting the first frame sub-detection image with uniform brightness and the first frame sub-detection image with uniform brightness is also uniform.
  • the target rows corresponding to the first group of second interlaced scans all become the latest scanned rows, and all rows of the target sample are scanned rows under the first direction scan. Therefore, during the second group of first interlaced scans, the scanning direction is changed to the second direction scan to overcome the problem of reflected electron path differences caused by the scanning direction.
  • the target line corresponding to the first interlaced scan of the second group is set to be the group of target lines with the longest time from the last scan, that is, the target line corresponding to the first interlaced scan of the first group; similarly, when the second group is interlaced for the second time, the target line corresponding to the first group of interlaced scans is set to be the target line corresponding to the second group of interlaced scans, so as to avoid two adjacent interlaced scans from scanning the same line, causing image defects in the detection.
  • the above example takes a group of interlaced scans including only two interlaced scans as an example. When a group of interlaced scans includes more interlaced scans, the scanning line sequence of two adjacent groups of interlaced scans can also be set to be the same, so as to avoid two adjacent interlaced scans from scanning the same line.
  • the brightness of the third sub-detection image generated according to the first interlaced scan of the second group is uniform
  • the brightness of the fourth sub-detection image generated according to the second interlaced scan of the second group is uniform
  • the brightness of the second detection image generated according to the third sub-detection image and the fourth sub-detection image is also uniform.
  • the detection image of the target sample generated according to the first detection image and the second detection image can compensate for the uneven imaging clarity caused by the different electron beam emission distances caused by the detection directions, and thus generate a detection image with uniform imaging clarity and uniform imaging brightness.
  • FIG. 4 is a flowchart of a scanning method 200 in another embodiment of the present disclosure.
  • the scanning method 200 further includes:
  • Step S41 after forming the second detection image, performing a third group of multiple interlaced scans on the target sample along the second direction to form a third detection image;
  • Step S42 performing a fourth set of multiple interlaced scans on the target sample along the first direction to form a fourth detection image.
  • a detection image can be formed by two sets of interlaced scans in opposite directions, due to the limited number of reflected electrons in each scan, at least four frames of detection images containing all the rows of the target sample are required to form a clear detection image that can accurately detect. Since in the embodiment shown in FIG3, only one set of detection images corresponding to interlaced scans can cover all the rows of the target sample, in the embodiment shown in FIG4, four sets of interlaced detections are required to form a clear detection image of the target sample.
  • the principle that the scanning line sequence in the second group of multiple interlaced scans is different from the scanning line sequence in the first group of multiple interlaced scans is the same, the scanning line sequence corresponding to the third group of multiple interlaced scans is different from the scanning line sequence corresponding to the second group of multiple interlaced scans, and the scanning line sequence corresponding to the fourth group of multiple interlaced scans is different from the scanning line sequence corresponding to the third group of multiple interlaced scans.
  • the target row corresponding to the last interlaced scan in the previous group is the same as the target row corresponding to the first interlaced scan in the next group, and the target row in the group is not given enough recovery time.
  • the next group of multiple interlaced scans is started after a preset time interval, so as to give each target row enough recovery time, and avoid the reduction of imaging clarity due to continuous scanning of a group of target rows.
  • the above-mentioned preset time length can be obtained according to actual measurement (the preset time length can make the imaging quality meet the self-set clarity standard), and the present disclosure does not impose any special restrictions on this.
  • the third group of multiple interlaced scans and the fourth group of multiple interlaced scans can also be set to have the same scanning line order as the second group of multiple interlaced scans, so that the target row corresponding to the first interlaced scan in the third group of multiple interlaced scans is different from the target row corresponding to the last interlaced scan in the second group of multiple interlaced scans, and the target row corresponding to the first interlaced scan in the fourth group of multiple interlaced scans is different from the target row corresponding to the last interlaced scan in the third group of multiple interlaced scans, giving each target row sufficient recovery time to ensure imaging clarity.
  • FIG. 5 is a schematic diagram of a scanning method in the embodiment shown in FIG. 4 .
  • the target sample 500 is divided into 16 rows (the actual number of rows is much greater than 16, and FIG5 is only an example), and the serial number of each row is shown in the figure.
  • the solid line indicates that the odd-numbered rows in the target sample 500 are scanned
  • the dotted line indicates that the even-numbered rows in the target sample 500 are scanned
  • the arrow indicates the scanning direction.
  • the order from top to bottom in FIG5 can be used, that is, the target sample 500 is scanned in the order of row numbers from small to large.
  • the first group of multiple interlaced scans 51 may include two interlaced scans, and the scanning line order is the first interlaced scan 511 corresponding to odd lines, and the second interlaced scan 512 corresponding to even lines;
  • the second group of multiple interlaced scans 52 include two interlaced scans, and the scanning line order is the third interlaced scan 521 corresponding to even lines, and the fourth interlaced scan 522 corresponding to odd lines;
  • the third group of multiple interlaced scans 53 include two interlaced scans, and the scanning line order is the fifth interlaced scan 531 corresponding to odd lines, and the sixth interlaced scan 532 corresponding to even lines;
  • the fourth group of multiple interlaced scans 54 include two interlaced scans, and the scanning line order is the seventh interlaced scan 541 corresponding to even lines, and the eighth interlaced scan 542 corresponding to odd lines.
  • a first detection image corresponding to the scanning direction of the first direction can be generated; through the second group of multiple interlaced scans 52, a second detection image corresponding to the scanning direction of the second direction can be generated; through the third group of multiple interlaced scans 53, a third detection image corresponding to the scanning direction of the second direction can be generated; through the fourth group of multiple interlaced scans 54, a fourth detection image corresponding to the scanning direction of the first direction can be generated.
  • a detection image of the target sample is generated according to the first detection image, the second detection image, the third detection image, and the fourth detection image.
  • a frame of detection image containing scanning information of all rows of the target sample is obtained through a set of two interlaced scans, and finally four frames of detection images formed in two relative scanning directions and two different scanning line orders are generated to form Frame*4.
  • a clear detection image of the target sample is formed by fitting and other means, which can overcome the imaging differences caused by the scanning direction and the scanning line order and improve the imaging accuracy of the scanned image. Due to the increase in the number of detection images involved in the calculation, the clarity and contrast of the target sample detection image finally generated are better than those in the embodiment shown in Figure 3. In addition, it has the advantages of uniform imaging clarity and uniform imaging brightness of the embodiment shown in Figure 3.
  • one interlaced scan corresponds to one scanning direction.
  • the scanning directions corresponding to two adjacent interlaced scans are the same, and the scanning directions of different groups of interlaced scans are different.
  • one interlaced scan to correspond to one scanning direction, and two adjacent interlaced scans to correspond to opposite scanning directions.
  • the target samples can still be scanned in groups.
  • FIG. 6 is a schematic diagram of a scanning method according to an embodiment of the present disclosure.
  • the first group of multiple interlaced scans 61 can be set to include a first interlaced scan 611 and a second interlaced scan 612.
  • the first interlaced scan 611 is a first direction scan for odd rows (row numbers see Figure 6)
  • the second interlaced scan 612 is a second direction scan for even rows.
  • the second group of multiple interlaced scans 62 includes a third interlaced scan 621 and a fourth interlaced scan 622.
  • the third interlaced scan 621 is a second direction scan for odd lines
  • the fourth interlaced scan 622 is a first direction scan for even lines.
  • the odd-numbered rows of the target sample are scanned in the first direction and in the second direction, and the even-numbered rows of the target sample are scanned in the first direction and in the second direction, thereby realizing the scanning of all rows of the target sample in two directions.
  • a first sub-detection image can be generated according to the data of the first detector 4 after the first interlaced scan 611 is completed
  • a second sub-detection image can be generated according to the data of the second detector 5 after the second interlaced scan 612 is completed
  • a third sub-detection image can be generated according to the data of the second detector 5 after the third interlaced scan 613 is completed
  • a fourth sub-detection image can be generated according to the data of the first detector 4 after the fourth interlaced scan 614 is completed.
  • a detection image of the target sample is generated according to the first sub-detection image, the second sub-detection image, the third sub-detection image, and the fourth sub-detection image.
  • four sub-detection images correspond to Frame*2.
  • a third group of interlaced detection and a fourth group of interlaced detection may be added according to the principle of the embodiment shown in FIG. 4 .
  • the scanning directions corresponding to adjacent target rows in one interlaced scan are opposite.
  • FIG. 7 is a schematic diagram of a scanning method in yet another embodiment of the present disclosure.
  • it may be configured to scan a plurality of target rows alternately in a first direction and a second direction in one interlaced scan.
  • the first group of multiple interlaced scans 71 includes a first interlaced scan 711 and a second interlaced scan 712.
  • the first interlaced scan 711 is to scan the odd rows (row numbers are shown in FIG. 7 ) alternately in the first direction and the second direction according to the sequence of the sequence numbers
  • the second interlaced scan 712 is to scan the even rows alternately in the first direction and the second direction according to the sequence of the sequence numbers.
  • the second group of multiple interlaced scans 72 includes a third interlaced scan 721 and a fourth interlaced scan 722.
  • the third interlaced scan 721 scans the odd lines alternately in the second direction and the first direction
  • the fourth interlaced scan 722 scans the even lines in the second direction and the first direction.
  • a first detection image can be generated based on the signal received by the first detector
  • a second detection image can be generated based on the signal received by the second detector.
  • a detection image of the target sample can be generated based on the first detection image and the second detection image.
  • the detection process corresponds to two detection images covering all rows of the target sample, namely, Frame*2.
  • a third group of interlaced detection and a fourth group of interlaced detection may be added according to the principle of the embodiment shown in FIG. 4 .
  • the scanning direction setting order corresponding to two adjacent interlaced scans is the same. In other embodiments of the present disclosure, the scanning direction setting order corresponding to two adjacent interlaced scans may also be opposite.
  • FIG. 8 is a schematic diagram of a scanning method in one embodiment of the present disclosure.
  • the first group of multiple interlaced scans 81 includes a first interlaced scan 811 and a second interlaced scan 812.
  • the first interlaced scan 811 is to scan the odd rows (row numbers are shown in Figure 8) alternately in the first direction and the second direction according to the sequence of the sequence numbers
  • the second interlaced scan 812 is to scan the even rows alternately in the second direction and the first direction according to the sequence of the sequence numbers.
  • the second group of multiple interlaced scans 82 includes a third interlaced scan 821 and a fourth interlaced scan 822.
  • the third interlaced scan 821 scans the odd lines alternately in the second direction and the first direction
  • the fourth interlaced scan 822 scans the even lines in the first direction and the second direction.
  • a first detection image can be generated based on the signal received by the first detector, and a second detection image can be generated based on the signal received by the second detector. Finally, a detection image of the target sample can be generated based on the first detection image and the second detection image.
  • the detection process corresponds to two detection images covering all rows of the target sample, namely, Frame*2.
  • a third group of interlaced detection and a fourth group of interlaced detection can be added according to the principle of the embodiment shown in FIG4 .
  • the embodiment of the present disclosure can solve the problem of uneven imaging clarity caused by differences in scanning order and scanning direction by setting two detectors in opposite directions and scanning the target sample in two directions; by performing interlaced scanning on the target sample, the problem of uneven imaging brightness caused by the flow of electrons in adjacent rows caused by progressive scanning can be solved, thereby greatly optimizing the imaging clarity of the detection image of the CDSEM and improving the detection accuracy of the target sample.
  • the disclosed embodiment can solve the problem of uneven imaging clarity caused by differences in scanning order and scanning direction by setting up two detectors in opposite directions and scanning the target sample in two directions; and can solve the problem of uneven imaging brightness caused by the flow of electrons in adjacent rows caused by progressive scanning by performing interlaced scanning on the target sample, thereby greatly optimizing the imaging clarity of the CDSEM detection image and improving the detection accuracy of the target sample.

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Abstract

一种扫描电子显微镜（100）的扫描方法以及扫描电子显微镜（100），扫描电子显微镜（100）包括对向设置的第一探测器（4）和第二探测器（5），扫描方法包括:分第一方向和第二方向对目标样品（10）进行多次隔行扫描，以根据第一探测器（4）和第二探测器（5）接收的电子束形成目标样品（10）的检测图像；其中，相邻两次隔行扫描对应的行不相同，多次隔行扫描对应目标样品（10）的全部行，目标样品（10）的每一行均对应至少两次隔行扫描，至少两次隔行扫描至少包括对该行进行第一方向的扫描和对该行进行第二方向的扫描，第二方向为第一方向的反方向。可以提供更准确的样品检测图像。

Description

扫描电子显微镜的扫描方法及扫描电子显微镜
交叉引用
本公开要求于2022年10月28日提交的申请号为2022113391173、名称为“扫描电子显微镜的扫描方法及扫描电子显微镜”的中国专利申请的优先权，该中国专利申请的全部内容通过引用全部并入本文。
技术领域
本公开涉及集成电路检测技术领域，具体而言，涉及一种扫描电子显微镜的扫描方法及执行该扫描方法的扫描电子显微镜。
背景技术
特征尺寸测量用扫描电子显微镜(Critical Dimension Scanning Electron Microscope，CDSEM)是一种根据图像的灰度(grey-scale)来确定图形的边界进而计算出集成电路中图形线宽的扫描电子显微镜。在检测过程中，通过以扫描形式对被测样品(集成电路)发射高能电子束，接收被测样品表面反射的电子束，根据反射电子束的密度来形成被测样品的扫描图像，以获取被测样品的微观形态，从而实现对被测样品中的目标区域进行进一步测量，例如测量图形线宽。
在相关技术中，CDSEM将按照设定的步长将扫描区域分为多个扫描行，对被测样品进行扫描，然后根据探测器接收的被测样品每一行反射的电子束中电子的数量进行拟合，来形成被测样品的检测图像。在实际运用过程中，CDSEM形成的检测图像通常会存在非样品原因导致的成像亮度不均匀、成像清晰度不均匀等问题，在对微观区域进行检测时，这种不均匀会导致检测结果出现误差。
需要说明的是，在上述背景技术部分公开的信息仅用于加强对本公开的背景的理解，因此可以包括不构成对本领域普通技术人员已知的现有技术的信息。
发明内容
本公开的目的在于提供一种扫描电子显微镜的扫描方法及扫描电子显微镜，用于至少在一定程度上克服CDSEM形成的检测图像存在非样品原因导致的成像清晰度不均匀问题。
根据本公开的第一方面，提供一种扫描电子显微镜的扫描方法，由扫描电子显微镜执行，所述扫描电子显微镜包括对向设置的第一探测器和第二探测器，所述扫描方法包括：分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像；其中，相邻两次所述隔行扫描对应的行不相同，所述多次隔行扫描对应所述目标样品的全部行，所述目标样品的每一行均对应 至少两次隔行扫描，所述至少两次隔行扫描至少包括对该行进行所述第一方向的扫描和对该行进行所述第二方向的扫描，所述第二方向为所述第一方向的反方向。
在本公开的一个示例性实施例中，分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像包括：沿所述第一方向对目标样品进行第一组多次隔行扫描，以根据所述第一探测器接收的电子束形成第一检测图像，所述第一组多次隔行扫描中每次所述隔行扫描对应的行均不相同，所述第一组多次隔行扫描对应所述目标样品的全部行；沿所述第二方向对所述目标样品进行第二组多次隔行扫描，以根据所述第二探测器接收的电子束形成第二检测图像，所述第二组多次隔行扫描中每次所述隔行扫描对应的行均不相同，所述第二组多次隔行扫描对应所述目标样品的全部行；根据所述第一检测图像和所述第二检测图像生成所述目标样品的检测图像。
在本公开的一个示例性实施例中，所述第一组多次隔行扫描的扫描行顺序与所述第二组多次隔行扫描的扫描行顺序相同。
在本公开的一个示例性实施例中，所述第一组多次隔行扫描的扫描行顺序与所述第二组多次隔行扫描的扫描行顺序不同。
在本公开的一个示例性实施例中，所述第一组多次隔行扫描包括两次隔行扫描，扫描行顺序为第一次隔行扫描对应奇数行，第二次隔行扫描对应偶数行；所述第二组多次隔行扫描包括两次隔行扫描，扫描行顺序为第三次隔行扫描对应偶数行，第四次隔行扫描对应奇数行。
在本公开的一个示例性实施例中，所述分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像还包括：在形成所述第二检测图像后，沿所述第二方向对所述目标样品进行第三组多次隔行扫描，以形成第三检测图像；沿所述第一方向对所述目标样品进行第四组多次隔行扫描，以形成第四检测图像。
在本公开的一个示例性实施例中，所述根据所述第一检测图像和所述第二检测图像生成所述目标样品的检测图像包括：根据所述第一检测图像、所述第二检测图像、所述第三检测图像、所述第四检测图像生成所述目标样品的检测图像。
在本公开的一个示例性实施例中，所述第三组多次隔行扫描对应的扫描行顺序与所述第二组多次隔行扫描对应的扫描行顺序不同，所述第四组多次隔行扫描对应的扫描行顺序与所述第三组多次隔行扫描对应的扫描行顺序不同。
在本公开的一个示例性实施例中，所述第一组多次隔行扫描包括两次隔行扫描，扫描行顺序为第一次隔行扫描对应奇数行，第二次隔行扫描对应偶数行；所述第二组多次隔行扫描包括两次隔行扫描，扫描行顺序为第三次隔行扫描对应偶数行，第四次隔行扫描对应奇数行；所述第三组多次隔行扫描包括两次隔行扫描，扫描行顺序为第五次隔行扫描对应奇数行，第六次隔行扫描对应偶数行；所述第四组多次隔行扫描包括两次隔行扫描，扫描 行顺序为第七次隔行扫描对应偶数行，第八次隔行扫描对应奇数行。
在本公开的一个示例性实施例中，一次所述隔行扫描对应一个扫描方向，且相邻两次所述隔行扫描对应的扫描方向相反。
在本公开的一个示例性实施例中，所述分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像包括：在第一次隔行扫描中对奇数行进行第一方向的扫描，以根据所述第一探测器的接收信息生成第一子检测图像；在第二次隔行扫描中对偶数行进行第二方向的扫描，以根据所述第二探测器的接收信息生成第二子检测图像；在第三次隔行扫描中对奇数行进行第二方向的扫描，以根据所述第二探测器的接收信息生成第三子检测图像；在第四次隔行扫描中对偶数行进行第一方向的扫描，以根据所述第一探测器的接收信息生成第四子检测图像；根据所述第一子检测图像、所述第二子检测图像、所述第三子检测图像、所述第四子检测图像生成所述目标样品的检测图像。
在本公开的一个示例性实施例中，一次所述隔行扫描对应多个目标行，在一次所述隔行扫描中相邻的所述目标行对应的扫描方向相反。
在本公开的一个示例性实施例中，相邻两次隔行扫描对应的扫描方向设置顺序相同。
在本公开的一个示例性实施例中，相邻两次隔行扫描对应的扫描方向设置顺序相反。
根据本公开的第二方面，提供一种扫描电子显微镜，所述扫描电子显微镜包括：镜筒，沿垂直轴线设置，用于沿所述垂直轴线发射电子束；电子偏转器，环绕所述垂直轴线设置，位于所述镜筒的下方，用于根据控制信号控制所述镜筒发射的所述电子束偏转；样品台，沿所述垂直轴线设置在所述电子偏转器的下方，水平设置，用于水平承载目标样品以使所述目标样品接收偏转后的所述电子束；第一探测器和第二探测器，沿所述垂直轴线相对设置在所述样品台和所述电子偏转器之间，用于接收所述目标样品反射的电子束；控制器，连接所述镜筒、所述电子偏转器、所述第一探测器和所述第二探测器，用于执行如上任一项所述的扫描方法，控制所述镜筒发射所述电子束，对所述电子偏转器发送所述控制信号以控制所述电子束偏转，接收所述第一探测器和所述第二探测器接收的电子束以生成所述目标样品的检测图像。
本公开实施例通过设置方向相对的两个探测器，并对目标样品进行两个方向的扫描，可以解决由扫描顺序和扫描方向差异带来的成像清晰度不均匀问题；通过对目标样品进行隔行扫描，可以解决由逐行扫描带来的相邻行电子流动导致的成像亮度不均匀问题，极大优化CDSEM的检测图像的成像清晰度，提高对目标样品的检测准确度。
应当理解的是，以上的一般描述和后文的细节描述仅是示例性和解释性的，并不能限制本公开。
附图说明
此处的附图被并入说明书中并构成本说明书的一部分，示出了符合本公开的实施例， 并与说明书一起用于解释本公开的原理。显而易见地，下面描述中的附图仅仅是本公开的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本公开示例性实施例中扫描电子显微镜的结构示意图。
图2是本公开实施例提供的扫描电子显微镜的扫描方法的流程图。
图3是本公开一个实施例中扫描方法的流程图。
图4是本公开另一个实施例中扫描方法的流程图。
图5是图4所示实施例中的扫描方法的示意图。
图6是本公开在一个实施例中扫描方法的示意图。
图7是本公开再一个实施例中扫描方法的示意图。
图8是本公开一个实施例中扫描方法的示意图。
具体实施方式
现在将参考附图更全面地描述示例实施方式。然而，示例实施方式能够以多种形式实施，且不应被理解为限于在此阐述的范例；相反，提供这些实施方式使得本公开将更加全面和完整，并将示例实施方式的构思全面地传达给本领域的技术人员。所描述的特征、结构或特性可以以任何合适的方式结合在一个或更多实施方式中。在下面的描述中，提供许多具体细节从而给出对本公开的实施方式的充分理解。然而，本领域技术人员将意识到，可以实践本公开的技术方案而省略所述特定细节中的一个或更多，或者可以采用其它的方法、组元、装置、步骤等。在其它情况下，不详细示出或描述公知技术方案以避免喧宾夺主而使得本公开的各方面变得模糊。
此外，附图仅为本公开的示意性图解，图中相同的附图标记表示相同或类似的部分，因而将省略对它们的重复描述。附图中所示的一些方框图是功能实体，不一定必须与物理或逻辑上独立的实体相对应。可以采用软件形式来实现这些功能实体，或在一个或多个硬件模块或集成电路中实现这些功能实体，或在不同网络和/或处理器装置和/或微控制器装置中实现这些功能实体。
下面结合附图对本公开示例实施方式进行详细说明。
图1是本公开示例性实施例中扫描电子显微镜的结构示意图。图1所示扫描电子显微镜100可以用于执行本公开实施例提供的扫描方法。
参考图1，扫描电子显微镜100可以包括：
镜筒1，沿垂直轴线设置，用于沿垂直轴线发射电子束；
电子偏转器2，环绕垂直轴线设置，位于镜筒1的下方，用于根据控制信号控制镜筒1发射的电子束偏转；
样品台3，沿垂直轴线设置在电子偏转器2的下方，水平设置，用于水平承载目标样品10以使目标样品10接收偏转后的电子束；
第一探测器4和第二探测器5，沿垂直轴线相对设置在样品台3和电子偏转器2之间，用于接收目标样品10反射的电子束；
控制器6，连接镜筒1、电子偏转器2、第一探测器4和第二探测器5，用于执行本公开实施例后续提供的扫描方法，控制镜筒1发射电子束，对电子偏转器2发送控制信号以偏转，以及接收第一探测器4和第二探测器5接收的电子束以生成目标样品10的检测图像。
图1所示的扫描电子显微镜100可以为特征尺寸测量用扫描电子显微镜，即CDSEM。目标样品10可以为待测的集成电路，例如为晶圆、芯片等，其中晶圆可以是完成涂覆光刻胶、完成光刻胶曝光显影的某个工艺过程后的半成品晶圆，此时，扫描电子显微镜100用于对目标样品10中曝光显影的光刻胶的缺陷进行扫描。
在实际控制过程中，控制器6用于对电子偏转器2输出第一控制信号，以通过电子偏转器2控制镜筒1发射的电子束由向水平方向的第一侧偏转逐渐变为向水平方向的第二侧偏转，以实现对目标样品的一行扫描；或者，控制器6用于对电子偏转器2输出第二控制信号，以通过电子偏转器2控制镜筒1发射的电子束由向水平方向的第二侧偏转逐渐变为向水平方向的第一侧偏转，以实现对目标样品的一行扫描。
在本公开实施例中，水平方向指与样品台3的载物表面平行的平面中的一个方向。第一探测器4设置在水平方向上的第二侧，第二探测器5设置在水平方向上的第一侧；或者，第一探测器4设置在水平方向上的第一侧，第二探测器5设置在水平方向上的第二侧。
在后续说明中，为了简化表述，将镜筒1由向水平方向的第一侧偏转逐渐变为向水平方向的第二侧偏转以实现对目标样品的一行扫描定义为沿第一方向对目标样品10进行扫描，将镜筒1由向水平方向的第二侧偏转逐渐变为向水平方向的第一侧偏转以实现对目标样品的一行扫描定义为沿第二方向对目标样品10进行扫描，由上述定义可知，第二方向为第一方向的相反方向，第一方向为第二方向的相反方向。
虽然在图1所示实施例中，仅设置了两个相对的第一探测器4和第二探测器5，但是在本公开的其他实施例中，还可以设置4个相对的探测器(每侧两个)或者6个相对的探测器(每侧三个)，只需要保证相对探测器的数量相等、位置对称即可，本公开对此不作特殊限制。
在本公开的另一个实施例中，扫描电子显微镜100还可以包括运动机构7，运动机构7连接样品台3和控制器6，用于根据控制器6发送的运动信号，配合电子束的偏转带动样品台3移动，以实现对目标样品的一行扫描。
在此实施例中，控制器6用于对电子偏转器2输出第三控制信号，以控制电子束向水平方向的第一侧偏转，同时对运动机构7输出第一运动信号，以控制样品台3从水平方向的第二侧向水平方向的第一侧移动，以实现对目标样品10从水平方向的第一侧向水平方向的第二侧进行扫描，即对目标样品10的一行进行第一方向的扫描。
或者，控制器6对电子偏转器2输出第四控制信号，以控制电子束向水平方向的第二侧偏转，同时对运动机构7输出第二运动信号，以控制样品台3从水平方向的第一侧向水平方向的第二侧移动，以实现对目标样品10的一行进行第二方向的扫描。
运动机构7可以设置，也可以不设置。当设置运动机构7时，可以设置电子束不偏转、样品台3运动，从而实现电子束与目标样品10进行第一方向或者第二方向的相对运动，即实现对目标样品10进行第一方向的扫描或者进行第二方向的扫描。如果不设置运动机构7，或者运动结构7不工作时，可以通过控制电子偏转器2来控制电子束偏转，从而实现电子束与目标样品10进行第一方向或者第二方向的相对运动，即实现对目标样品10进行第一方向的扫描或者进行第二方向的扫描。
无论是否设置运动结构7，本公开后续实施例中均统一以“对目标样品进行第一方向/第二方向的扫描”来指代上述控制过程，以简化表述。
图2是本公开实施例提供的扫描电子显微镜的扫描方法的流程图。图2所示的扫描方法由图1所示的扫描电子显微镜执行。
参考图2，在本公开实施例中，扫描方法200可以包括：
分第一方向和第二方向对目标样品进行多次隔行扫描，以根据第一探测器和第二探测器接收的电子束形成目标样品的检测图像。
其中，相邻两次隔行扫描对应的行不相同，多次隔行扫描对应目标样品的全部行，目标样品的每一行均对应至少两次隔行扫描，至少两次隔行扫描至少包括对该行进行第一方向的扫描和对该行进行第二方向的扫描，第二方向为第一方向的反方向。
现有的扫描电子显微镜的扫描方法，是按照从左到右的扫描模式依次对目标样品进行从上到下的扫描顺序进行扫描。从上到下完整扫描一次生成的子检测图像可以被标记为Frame*1，最终，由多次扫描结果结合而成的目标样品的检测图像可以被标记为Frame*4、Frame*8、或者Frame*16，其中4、8、16分别是生成的子检测图像的数量。
根据分析，造成现有的扫描电子显微镜的检测图像出现成像不均匀、亮度不均匀的原因是，先扫描区域被电子束轰击从而产生电子反射之后会留下空穴，导致相邻未扫描区域的电子流动到先扫描区域的空穴部分，造成后扫描区域的电子反射量相对于先扫描区域的电子反射量出现明显降低，进而导致根据不同区域的电子反射量来标记检测图像的区域亮度时，先扫描区域的亮度高于后扫描区域的亮度，造成成像亮度不均匀。此外，由于现有的扫描电子显微镜中硬件检测装置设置在机台一侧，导致另一侧的反射电子在偏转过程中出现由距离导致的消耗，因此根据电子反射量得到的图像拟合结果上下和左右均有差异，最终导致量测结果不准确。
在本公开实施例中，为了解决上述问题，首先对扫描电子显微镜进行机台改进，即设置了方向相对的两个探测器，以实现从两个相反方向对目标样品进行扫描，克服反射电子由于出射角度和进入探测器的入射角度不同、电子反射距离不同导致的电子损耗，修复成像清晰度不均匀问题。此外，设置对目标样品进行隔行扫描，给与先扫描区域相 邻的未扫描区域合适的电子恢复时间，克服由于相邻区域之间的载流子耦合导致的后扫描区域电子反射量减小，即解决电子束在物体表面反射的电子数量不均匀问题、成像亮度不均匀问题。
图3是本公开一个实施例中扫描方法200的流程图。
参考图3，在本公开的一个示例性实施例中，扫描方法200可以包括：
步骤S31，沿第一方向对目标样品进行第一组多次隔行扫描，以根据第一探测器接收的电子束形成第一检测图像，第一组多次隔行扫描中每次隔行扫描对应的行均不相同，第一组多次隔行扫描对应目标样品的全部行；
步骤S32，沿第二方向对目标样品进行第二组多次隔行扫描，以根据第二探测器接收的电子束形成第二检测图像，第二组多次隔行扫描中每次隔行扫描对应的行均不相同，第二组多次隔行扫描对应目标样品的全部行；
步骤S33，根据第一检测图像和第二检测图像生成目标样品的检测图像。
图3所示实施例中，先后对目标样品进行两个方向的扫描，最后根据沿第一方向的扫描检测图像(第一检测图像)和沿第二方向的扫描检测图像(第二检测图像)共同生成目标样品的检测图像。
结合图1，在第一方向的扫描中，对目标样品10的每一行的扫描均为沿第一方向扫描，反射电子束由第一探测器4接收。在第二方向的扫描中，对目标样品10的每一行的扫描均为沿第二方向扫描，反射电子束由第二探测器5接收。
在每个方向对应的扫描中，均包括多次隔行扫描，每次隔行扫描均可以生成一帧子检测图像(即前文所述的Frame)。隔行扫描是指两次扫描的行不相邻。在本公开实施例中，一次隔行扫描对应多个目标行，相邻的目标行之间至少间隔一行。假设扫描电子显微镜100将对目标样品10的检测分成了N行，最小一行的序号为1，则当目标行之间间隔一行时，一次隔行扫描可以对应目标样品的第1、3、5、7、9……行，也可以对应第2、4、6、8、10……行；当目标行之间间隔两行时，一次隔行扫描可以对应第1、4、7、10……行，也可以对应地2、5、8、11……行，也可以对应3、6、9、12……行。以此类推，不再赘述。
当一次隔行扫描的目标行之间间隔一行时，一组隔行扫描至少对应两次隔行扫描(例如起始扫描行分别为第1行、第2行的两次隔行扫描)，以实现对目标样品的全部行的扫描；当一次隔行扫描的目标行之间间隔两行时，一组隔行扫描至少对应三次隔行扫描(例如起始扫描行分别为第1行、第2行、第3行的三次隔行扫描)，以实现对目标样品的全部行的扫描。
上述的扫描顺序可以被称为扫描行顺序。在图2所示实施例中，第一组多次隔行扫描的扫描行顺序与第二组多次隔行扫描的扫描行顺序相同，或者，第一组多次隔行扫描的扫描行顺序与第二组多次隔行扫描的扫描行顺序不同。
当第一组多次隔行扫描的扫描行顺序与第二组多次隔行扫描的扫描行顺序相同时， 在一个实施例中，第一组多次隔行扫描包括两次隔行扫描，扫描行顺序为第一次隔行扫描对应奇数行(例如第1、3、5、7、9……行)，第二次隔行扫描对应偶数行(例如第2、4、6、8、10……行)；第二组多次隔行扫描包括两次隔行扫描，扫描行顺序同样为第一次隔行扫描对应奇数行，第二次隔行扫描对应偶数行。此时，第一组多次隔行扫描通过两次隔行扫描生成2帧子检测图像，第二组多次隔行扫描也通过两次隔行扫描生成2帧子检测图像，共生成4帧子检测图像，即Frame*4。最后，根据4帧子检测图像生成目标样品的检测图像。
当第一组多次隔行扫描的扫描行顺序与第二组多次隔行扫描的扫描行顺序不同时，在一个实施例中，第一组多次隔行扫描包括两次隔行扫描，扫描行顺序为第一次隔行扫描对应奇数行(例如第1、3、5、7、9……行)，第二次隔行扫描对应偶数行(例如第2、4、6、8、10……行)；第二组多次隔行扫描包括两次隔行扫描，扫描行顺序为第一次隔行扫描对应偶数行，第二次隔行扫描对应奇数行。此时，第一组多次隔行扫描通过两次隔行扫描生成2帧子检测图像，第二组多次隔行扫描也通过两次隔行扫描生成2帧子检测图像，共生成4帧子检测图像，即Frame*4。最后，根据4帧子检测图像生成目标样品的检测图像。
由于使用了隔行扫描，在形成第一帧子检测图像的过程中，即使相邻行出现了电子转移(载流子中和)，也不会对间隔至少一行的两个相邻的目标行的扫描效果的均匀性造成影响，第一组第一次隔行扫描形成的子检测图像的亮度均匀。当形成一帧子检测图像后，第一组第一次隔行扫描对应的目标行均成为已扫描行。在进行第一组第二次隔行扫描时，第一组第二次扫描对应的各目标行(未扫描行)的电子数量相近(因为各目标行与已扫描行的相对位置关系相同)，第一组第二次隔行扫描形成的第二帧子检测图像的亮度均匀。根据亮度均匀的第一帧子检测图像和亮度均匀的第一帧子检测图像拟合生成的第一检测图像的亮度也均匀。
在完成第一组第二次隔行扫描后，第一组第二次隔行扫描对应的目标行均成为最新的已扫描行，至此目标样品的全部行均为第一方向扫描下的已扫描行。因此，在第二组第一次隔行扫描时，将扫描方向更换为第二方向的扫描，克服由扫描方向导致的反射电子路径差异问题。
当设置两组隔行扫描对应的扫描行顺序相同时，将第二组第一次隔行扫描对应的目标行设置为距离上次扫描时间最长的一组目标行，即第一组第一次隔行扫描对应的目标行；同理，在第二组第二次隔行扫描时，将第一组第二次隔行扫描对应的目标行设置为第二组第二次隔行扫描对应的目标行，以避免相邻两次隔行扫描对同一行进行扫描，造成检测图像缺陷。以上示例以一组隔行扫描仅包括两次隔行扫描为例，当一组隔行扫描包括更多次隔行扫描时，同样可以设置相邻两组隔行扫描的扫描行顺序相同，以避免相邻两次隔行扫描对同一行进行扫描。
当设置两组隔行扫描对应的扫描行顺序不同时，能够在不同扫描行顺序下得到与不 同扫描行顺序对应的子检测图像，降低扫描行顺序差异导致的扫描图像差异。
最终，根据第二组第一次隔行扫描生成的第三子检测图像的亮度均匀，根据第二组第二次隔行扫描生成的第四子检测图像的亮度均匀，根据第三子检测图像和第四子检测图像生成的第二检测图像的亮度也均匀。
由于第一检测图像反应的是从第一方向进行扫描的检测效果，第二检测图像反应的是从第一方向的反方向进行扫描的检测效果，根据第一检测图像和第二检测图像生成的目标样本的检测图像可以弥补由于检测方向带来的电子束出射距离不同导致的成像清晰度不均匀，进而生成成像清晰度均匀、成像亮度均匀的检测图像。
图4是本公开另一个实施例中扫描方法200的流程图。
参考图4，在本公开的一个示例性实施例中，扫描方法200还包括：
步骤S41，在形成第二检测图像后，沿第二方向对目标样品进行第三组多次隔行扫描，以形成第三检测图像；
步骤S42，沿第一方向对目标样品进行第四组多次隔行扫描，以形成第四检测图像。
虽然在图3所示实施例中，能够通过两组方向相反的隔行扫描形成检测图像，但是由于每次扫描的反射电子数量有限，形成能够准确进行检测的清晰检测图像至少需要4帧包含目标样品全部行的检测图像。由于在图3所示实施例中一组隔行扫描对应的检测图像才能覆盖目标样品的全部行，因此在图4所示实施例中，需要对目标样品进行四组隔行检测，以形成目标样品的清晰检测图像。
与第二组多次隔行扫描中的扫描行顺序和第一组多次隔行扫描中的扫描行顺序不同的原理相同，第三组多次隔行扫描对应的扫描行顺序与第二组多次隔行扫描对应的扫描行顺序不同，第四组多次隔行扫描对应的扫描行顺序与第三组多次隔行扫描对应的扫描行顺序不同。由于设置相邻两组多次隔行扫描的行扫描顺序不同，可能在相邻两组多次隔行扫描中，前一组中最后一次隔行扫描对应的目标行与后一组第一次隔行扫描对应的目标行相同，未给该组目标行足够的恢复时间。在本公开的一个实施例中，可以在设置不同组多次隔行扫描对应不同行扫描顺序时，每完成一组多次隔行扫描后，间隔预设时长再开启下一组多次隔行扫描，以给各目标行足够的恢复时间，避免由于连续扫描一组目标行导致成像清晰度降低。上述预设时长可以根据实际测量(该预设时长能够使得成像质量满足自行设定的清晰标准)得到，本公开对此不作特殊限制。
在本公开的其他实施例中，也可以设置第三组多次隔行扫描、第四组多次隔行扫描均与第二组多次隔行扫描的扫描行顺序相同，从而使得第三组多次隔行扫描中的第一次隔行扫描对应的目标行与第二组多次隔行扫描中的最后一次隔行扫描对应的目标行不同，第四组多次隔行扫描中的第一次隔行扫描对应的目标行与第三组多次隔行扫描中的最后一次隔行扫描对应的目标行不同，给各目标行足够的恢复时间，保证成像清晰度。
图5是图4所示实施例中的扫描方法的示意图。
参考图5，假设目标样品500被分为16行(实际上的行数远大于16，图5仅为示 例)，每行的序号如图所示。以实线表示对目标样品500中的奇数行进行扫描，以虚线表示目标样品500中的偶数行进行扫描，以箭头表示扫描方向。在每次隔行扫描中，例如均可以为在图5中从上到下的顺序，即按照行序号由少到多的顺序对目标样品500中进行行扫描。
在一个实施例中，第一组多次隔行扫描51可以包括两次隔行扫描，扫描行顺序为第一次隔行扫描511对应奇数行，第二次隔行扫描512对应偶数行；第二组多次隔行扫描52包括两次隔行扫描，扫描行顺序为第三次隔行扫描521对应偶数行，第四次隔行扫描522对应奇数行；第三组多次隔行扫描53包括两次隔行扫描，扫描行顺序为第五次隔行扫描531对应奇数行，第六次隔行扫描532对应偶数行；第四组多次隔行扫描54包括两次隔行扫描，扫描行顺序为第七次隔行扫描541对应偶数行，第八次隔行扫描542对应奇数行。
通过第一组多次隔行扫描51，可以生成对应扫描方向为第一方向的第一检测图像；通过第二组多次隔行扫描52，可以生成对应扫描方向为第二方向的第二检测图像；通过第三组多次隔行扫描53，可以生成对应扫描方向为第二方向的第三检测图像；通过第四组多次隔行扫描54，可以生成对应扫描方向为第一方向的第四检测图像。
最后，根据第一检测图像、第二检测图像、第三检测图像、第四检测图像生成目标样品的检测图像。
在本公开实施例中，通过一组两次隔行扫描获得包含目标样品的全部行的扫描信息一帧检测图像，最终生成在两个相对的扫描方向、两个不同的扫描行顺序下形成的四帧检测图像，形成Frame*4，通过拟合等手段构成目标样品的清晰的检测图像，可以克服扫描方向、扫描行顺序带来的成像差异，提高扫描图像的成像准确度。由于参与计算的检测图像数量增多，最终生成的目标样品检测图像的清晰度、对比度均比图3所示实施例中具有更好的效果，此外，具备图3所示实施例的成像清晰度均匀、成像亮度均匀等优点。
在图3、图4所示实施例中，一次隔行扫描对应一个扫描方向，在一组隔行扫描中，相邻两次隔行扫描对应的扫描方向相同，不同组隔行扫描的扫描方向不同。
在本公开的再一个实施例中，也可以设置一次隔行扫描对应一个扫描方向，且相邻两次隔行扫描对应的扫描方向相反。在此实施例中，仍然可以分组对目标样品进行扫描。
图6是本公开在一个实施例中扫描方法的示意图。
参考图6，在一个实施例中，可以设第一组多次隔行扫描61包括第一次隔行扫描611和第二次隔行扫描612，第一次隔行扫描611为对奇数行(行序号见图6)进行第一方向扫描，第二次隔行扫描612为对偶数行进行第二方向扫描。
同时，设第二组多次隔行扫描62包括第三次隔行扫描621和第四次隔行扫描622，第三次隔行扫描621为对奇数行进行第二方向扫描，第四次隔行扫描622为对偶数行进行第一方向扫描。
至此，完成对目标样品的奇数行进行第一方向的扫描和第二方向的扫描，以及对目标样品的偶数行进行第一方向的扫描和第二方向的扫描，实现对目标样品全部行的两个方向的扫描。在此实施例中，可以在第一次隔行扫描611结束后根据第一探测器4的数据生成第一子检测图像，在第二次隔行扫描612结束后根据第二探测器5的数据生成第二子检测图像，在第三次隔行扫描613结束后根据第二探测器5的数据生成第三子检测图像，在第四次隔行扫描614结束后根据第一探测器4的数据生成第四子检测图像，最后，根据第一子检测图像、第二子检测图像、第三子检测图像、第四子检测图像生成目标样品的检测图像。
在图6所示实施例中，四张子检测图像对应Frame*2，为了增强成像质量，可以根据图4所示实施例的原理，增加第三组隔行检测和第四组隔行检测。
在本公开的再一个实施例中，也可以设置在一次隔行扫描中相邻的目标行对应的扫描方向相反。
图7是本公开再一个实施例中扫描方法的示意图。
参考图7，在一个实施例中，可以设置在一次隔行扫描中对多个目标行进行第一方向和第二方向交替的扫描。
设第一组多次隔行扫描71包括第一次隔行扫描711和第二次隔行扫描712，第一次隔行扫描711为对奇数行(行序号见图7)按照序号顺序进行第一方向和第二方向交替的扫描，第二次隔行扫描712为对偶数行按照序号顺序进行第一方向和第二方向交替的扫描。
同时，设第二组多次隔行扫描72包括第三次隔行扫描721和第四次隔行扫描722，第三次隔行扫描721为对奇数行进行第二方向和第一方向交替的扫描，第四次隔行扫描722为对偶数行进行第二方向和第一方向扫描。
至此，完成对目标样品的奇数行进行第一方向的扫描和第二方向的扫描，以及对目标样品的偶数行进行第一方向的扫描和第二方向的扫描，实现对目标样品全部行的两个方向的扫描。在此实施例中，可以四次隔行扫描结束后，根据第一探测器接收的信号生成第一检测图像，根据第二探测器接收的信号生成第二检测图像，最后，根据第一检测图像、第二检测图像生成目标样品的检测图像。
在图7所示实施例中，检测过程对应两张覆盖目标样品全部行的检测图像，即Frame*2，为了增强成像质量，可以根据图4所示实施例的原理，增加第三组隔行检测和第四组隔行检测。
在图7所示检测方法中，当电子束由图7中的左侧逐渐偏转到图7中的右侧，即完成对第一方向的扫描时，无需将电子束的偏转方向调整回图7中的左侧，直接对下一个目标行进行扫描，从而可以节省调整电子偏转角度的时间，即无需对图1中的电子偏转器2进行重置，继续按照当前偏转角度反向调节即可。在扫描行数量较大时，可以提高扫描效率。
图7所示检测方法中，相邻两次隔行扫描对应的扫描方向设置顺序相同，在本公开的其他实施例中，还可以设置相邻两次隔行扫描对应的扫描方向设置顺序相反。
图8是本公开一个实施例中扫描方法的示意图。
参考图8，设第一组多次隔行扫描81包括第一次隔行扫描811和第二次隔行扫描812，第一次隔行扫描811为对奇数行(行序号见图8)按照序号顺序进行第一方向和第二方向交替的扫描，第二次隔行扫描812为对偶数行按照序号顺序进行第二方向和第一方向交替的扫描。
同时，设第二组多次隔行扫描82包括第三次隔行扫描821和第四次隔行扫描822，第三次隔行扫描821为对奇数行进行第二方向和第一方向交替的扫描，第四次隔行扫描822为对偶数行进行第一方向和第二方向扫描。
至此，完成对目标样品的奇数行进行第一方向的扫描和第二方向的扫描，以及对目标样品的偶数行进行第一方向的扫描和第二方向的扫描，实现对目标样品全部行的两个方向的扫描。与图7所示实施例相同，可以四次隔行扫描结束后，根据第一探测器接收的信号生成第一检测图像，根据第二探测器接收的信号生成第二检测图像，最后，根据第一检测图像、第二检测图像生成目标样品的检测图像。
同样，在图8所示实施例中，检测过程对应两张覆盖目标样品全部行的检测图像，即Frame*2，为了增强成像质量，可以根据图4所示实施例的原理，增加第三组隔行检测和第四组隔行检测。
上述实施例仅为有限列举，在实际实施中，本领域技术人员可以根据实际需求设置每次隔行检测的目标行和检测方向、相邻目标行的检测方向关系、相邻两次隔行检测的目标行和检测方向的关系、每组隔行检测中隔行检测的次数，以及多次隔行检测的组数，只要能够保障对目标样品的每一行均进行了第一方向的隔行扫描和第二方向的隔行扫描即可，本公开实施例于此不在穷举。
综上所述，本公开实施例通过设置方向相对的两个探测器，并对目标样品进行两个方向的扫描，可以解决由扫描顺序和扫描方向差异带来的成像清晰度不均匀问题；通过对目标样品进行隔行扫描，可以解决由逐行扫描带来的相邻行电子流动导致的成像亮度不均匀问题，极大优化CDSEM的检测图像的成像清晰度，提高对目标样品的检测准确度。
应当注意，尽管在上文详细描述中提及了用于动作执行的设备的若干模块或者单元，但是这种划分并非强制性的。实际上，根据本公开的实施方式，上文描述的两个或更多模块或者单元的特征和功能可以在一个模块或者单元中具体化。反之，上文描述的一个模块或者单元的特征和功能可以进一步划分为由多个模块或者单元来具体化。
本领域技术人员在考虑说明书及实践这里公开的发明后，将容易想到本公开的其它实施方案。本申请旨在涵盖本公开的任何变型、用途或者适应性变化，这些变型、用途或者适应性变化遵循本公开的一般性原理并包括本公开未公开的本技术领域中的公知常识或 惯用技术手段。说明书和实施例仅被视为示例性的，本公开的真正范围和构思由权利要求指出。
工业实用性
本公开实施例通过设置方向相对的两个探测器，并对目标样品进行两个方向的扫描，可以解决由扫描顺序和扫描方向差异带来的成像清晰度不均匀问题；通过对目标样品进行隔行扫描，可以解决由逐行扫描带来的相邻行电子流动导致的成像亮度不均匀问题，极大优化CDSEM的检测图像的成像清晰度，提高对目标样品的检测准确度。

Claims (15)

  1. 一种扫描电子显微镜的扫描方法，由扫描电子显微镜执行，所述扫描电子显微镜包括对向设置的第一探测器和第二探测器，所述扫描方法包括：
    分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像；
    其中，相邻两次所述隔行扫描对应的行不相同，所述多次隔行扫描对应所述目标样品的全部行，所述目标样品的每一行均对应至少两次隔行扫描，所述至少两次隔行扫描至少包括对该行进行所述第一方向的扫描和对该行进行所述第二方向的扫描，所述第二方向为所述第一方向的反方向。
  2. 如权利要求1所述的扫描方法，其中，分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像包括：
    沿所述第一方向对目标样品进行第一组多次隔行扫描，以根据所述第一探测器接收的电子束形成第一检测图像，所述第一组多次隔行扫描中每次所述隔行扫描对应的行均不相同，所述第一组多次隔行扫描对应所述目标样品的全部行；
    沿所述第二方向对所述目标样品进行第二组多次隔行扫描，以根据所述第二探测器接收的电子束形成第二检测图像，所述第二组多次隔行扫描中每次所述隔行扫描对应的行均不相同，所述第二组多次隔行扫描对应所述目标样品的全部行；
    根据所述第一检测图像和所述第二检测图像生成所述目标样品的检测图像。
  3. 如权利要求2所述的扫描方法，其中，所述第一组多次隔行扫描的扫描行顺序与所述第二组多次隔行扫描的扫描行顺序相同。
  4. 如权利要求2所述的扫描方法，其中，所述第一组多次隔行扫描的扫描行顺序与所述第二组多次隔行扫描的扫描行顺序不同。
  5. 如权利要求2或4所述的扫描方法，其中，所述第一组多次隔行扫描包括两次隔行扫描，扫描行顺序为第一次隔行扫描对应奇数行，第二次隔行扫描对应偶数行；所述第二组多次隔行扫描包括两次隔行扫描，扫描行顺序为第三次隔行扫描对应偶数行，第四次隔行扫描对应奇数行。
  6. 如权利要求2所述的扫描方法，其中，所述分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像还包括：
    在形成所述第二检测图像后，沿所述第二方向对所述目标样品进行第三组多次隔行扫描，以形成第三检测图像；
    沿所述第一方向对所述目标样品进行第四组多次隔行扫描，以形成第四检测图像。
  7. 如权利要求6所述的扫描方法，其中，所述根据所述第一检测图像和所述第二检测 图像生成所述目标样品的检测图像包括：
    根据所述第一检测图像、所述第二检测图像、所述第三检测图像、所述第四检测图像生成所述目标样品的检测图像。
  8. 如权利要求6所述的扫描方法，其中，所述第三组多次隔行扫描对应的扫描行顺序与所述第二组多次隔行扫描对应的扫描行顺序不同，所述第四组多次隔行扫描对应的扫描行顺序与所述第三组多次隔行扫描对应的扫描行顺序不同。
  9. 如权利要求8所述的扫描方法，其中，
    所述第一组多次隔行扫描包括两次隔行扫描，扫描行顺序为第一次隔行扫描对应奇数行，第二次隔行扫描对应偶数行；
    所述第二组多次隔行扫描包括两次隔行扫描，扫描行顺序为第三次隔行扫描对应偶数行，第四次隔行扫描对应奇数行；
    所述第三组多次隔行扫描包括两次隔行扫描，扫描行顺序为第五次隔行扫描对应奇数行，第六次隔行扫描对应偶数行；
    所述第四组多次隔行扫描包括两次隔行扫描，扫描行顺序为第七次隔行扫描对应偶数行，第八次隔行扫描对应奇数行。
  10. 如权利要求1所述的扫描方法，其中，一次所述隔行扫描对应一个扫描方向，且相邻两次所述隔行扫描对应的扫描方向相反。
  11. 如权利要求10所述的扫描方法，其中，所述分第一方向和第二方向对目标样品进行多次隔行扫描，以根据所述第一探测器和所述第二探测器接收的电子束形成所述目标样品的检测图像包括：
    在第一次隔行扫描中对奇数行进行第一方向的扫描，以根据所述第一探测器的接收信息生成第一子检测图像；
    在第二次隔行扫描中对偶数行进行第二方向的扫描，以根据所述第二探测器的接收信息生成第二子检测图像；
    在第三次隔行扫描中对奇数行进行第二方向的扫描，以根据所述第二探测器的接收信息生成第三子检测图像；
    在第四次隔行扫描中对偶数行进行第一方向的扫描，以根据所述第一探测器的接收信息生成第四子检测图像；
    根据所述第一子检测图像、所述第二子检测图像、所述第三子检测图像、所述第四子检测图像生成所述目标样品的检测图像。
  12. 如权利要求1所述的扫描方法，其中，一次所述隔行扫描对应多个目标行，在一次所述隔行扫描中相邻的所述目标行对应的扫描方向相反。
  13. 如权利要求12所述的扫描方法，其中，相邻两次隔行扫描对应的扫描方向设置顺序相同。
  14. 如权利要求12所述的扫描方法，其中，相邻两次隔行扫描对应的扫描方向设置顺 序相反。
  15. 一种扫描电子显微镜，所述扫描电子显微镜包括：
    镜筒，沿垂直轴线设置，用于沿所述垂直轴线发射电子束；
    电子偏转器，环绕所述垂直轴线设置，位于所述镜筒的下方，用于根据控制信号控制所述镜筒发射的所述电子束偏转；
    样品台，沿所述垂直轴线设置在所述电子偏转器的下方，水平设置，用于水平承载目标样品以使所述目标样品接收偏转后的所述电子束；
    第一探测器和第二探测器，沿所述垂直轴线相对设置在所述样品台和所述电子偏转器之间，用于接收所述目标样品反射的电子束；
    控制器，连接所述镜筒、所述电子偏转器、所述第一探测器和所述第二探测器，用于执行如权利要求1-14任一项所述的扫描方法，控制所述镜筒发射所述电子束，对所述电子偏转器发送所述控制信号以控制所述电子束偏转，接收所述第一探测器和所述第二探测器接收的电子束以生成所述目标样品的检测图像。
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