Charged particle beam system for scanning samples

Abstract

A method for scanning a sample using a charged particle beam tool is provided. The method comprises providing a sample having a scanning area including a plurality of unit areas, scanning a unit area among the plurality of unit areas, blocking a next unit area adjacent to the scanned unit area among the plurality of unit areas, and scanning and blocking the plurality of unit areas until all unit areas are scanned.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Application No. 62 / 787,121, filed December 31, 2018, and U.S. Application No. 62 / 943,695, filed December 4, 2019, which are incorporated herein by reference in their entirety. Technical Field

[0003] Apparatus and methods according to the present disclosure relate generally to scanning techniques, and more particularly to methods and systems for scanning a sample by a charged particle beam tool such as a scanning electron microscope (SEM). Background Art

[0004] In the manufacturing process of integrated circuits (ICs), unfinished or completed circuit components are inspected to ensure that they are manufactured according to the design and have no defects. An inspection system using an optical microscope or a charged particle (e.g., electron) beam microscope (e.g., SEM) can be used. For the inspection of fine structures, electron beams are preferred. Using electron beams to carry out such inspections on samples can cause the problem of charge accumulation in the sample. In order to solve the problem of charge accumulation, technicians usually sputter a few nanometers of thick high conductive materials or thin films (such as gold thin films) on the sample surface to conduct the charge away from the scanning area of ​​the sample. However, this method can destroy the device structure originally designed, and will not allow the sample to be used as a device, because blocking the blanket-coated gold layer will short-circuit all circuits formed on the sample. Further improvements in this field are expected. Summary of the invention

[0005] According to some embodiments of the present invention, a method for scanning a sample by a charged particle beam tool (such as an electron beam tool) is provided. The method may include: providing a sample having a scanning area, wherein the sample is determined to have a plurality of unit areas; scanning a unit area in the plurality of unit areas; and blocking a first unit area adjacent to the scanned unit area.

[0006] The method may further include: determining whether any unit area to be scanned remains on the sample; in response to determining that any unit area to be scanned remains on the sample, scanning a next unit area, the next unit area being determined to be outside the determined dissipation area associated with the scanned unit area; and blocking a second unit area adjacent to the scanned next unit area. The method may further include: blocking a third unit area adjacent to the blocked first unit area before scanning the next unit area. In the method, the blocked first unit area may include a plurality of unit areas.

[0007] In the method, the blocked first unit area is adjacent to the scanned unit area in the X direction. In the method, the blocked first unit area is adjacent to the scanned unit area in the Y direction. In the method, the scanned unit area may be a single pixel of the scanned image. In the method, the blocked first unit area may be a single pixel. In the method, the blocked first unit area may be a plurality of pixels. In the method, the scanned unit area may be a plurality of pixels of the scanned image.

[0008] In the method, blocking a first unit area adjacent to the scanned unit area may further include: applying current to an electromagnetic blocker so that an electromagnetic field generated by the blocker deflects an electron beam of the electron beam tool so that the electron beam no longer reaches the sample.

[0009] In the method, blocking a first unit area adjacent to the scanned unit area further comprises: moving a shutter to intercept a path of an electron beam of an electron beam tool so that the electron beam no longer reaches the sample. In the method, scanning and blocking can be determined based on a dissipation time for charge dissipation in the scanned unit area. In the method, scanning and blocking can be performed on a predetermined pattern in the sample.

[0010] In the method, the predetermined pattern may be one of the following: a line pattern parallel to an edge of the scanning area, a diagonal line pattern in the scanning area, or a circular pattern. In the method, scanning and blocking are performed on the plurality of unit areas until all unit areas are scanned.

[0011] The method may further include: reconstructing an image of the sample using sub-images corresponding to the scanned plurality of unit regions. In the method, the reconstruction may be performed by using at least one of interpolation, sparse sampling, or simulation. In the method, the plurality of unit regions in the scanned region are organized into batches of unit regions provided in rows or columns, and the scanned unit regions and the blocked unit regions are in the first batch of unit regions.

[0012] In the method, after scanning and blocking the cell regions of the first batch: blocking or skipping the cell regions of the second batch adjacent to the first batch; and scanning and blocking the cell regions of the third batch at least a threshold distance from the first batch to mitigate the distortion caused by the charge of the scanned cell regions from the first batch. The method may also include: after a dissipation time threshold, returning to the cell regions of the first batch to scan the cell regions that were not previously scanned to mitigate the distortion caused by the charge of the previously scanned cell regions from the first batch.

[0013] According to some embodiments of the present disclosure, a scanning electron microscope (SEM) is provided. The SEM may include: an electron source; a scanning deflector for scanning an electron beam emitted from the electron source over a scanning area of ​​a sample, wherein the sample is determined to have a plurality of unit areas; a blocker for blocking the electron beam so that the electron beam no longer reaches the sample; and a controller including a circuit device for controlling the scanning deflector and the blocker, wherein the controller is configured to: scan a unit area among a plurality of unit areas; and block a first unit area adjacent to the scanned unit area.

[0014] In the SEM, the controller can also be configured to: determine whether there are any unit areas remaining to be scanned on the sample; in response to determining that there are any unit areas remaining to be scanned on the sample, scan the next unit area that is greater than a predetermined distance from the scanned unit area; and block a second unit area adjacent to the next unit area to be scanned.

[0015] In the SEM, the controller may be further configured to: block a third unit area adjacent to the blocked first unit area before scanning the next unit area. In the SEM, the blocked first unit area includes a plurality of unit areas. In the SEM, the blocked first unit area may be adjacent to the scanned unit area in the X direction. In the SEM, the blocked first unit area may be adjacent to the scanned unit area in the Y direction. In the SEM, the scanned unit area may be a single pixel of the scanned image. In the SEM, the blocked first unit area may be a single pixel. In the SEM, the blocked first unit area may be a plurality of pixels. In the SEM, the scanned unit area may be a plurality of pixels of the scanned image.

[0016] In the SEM, the blocker may be an electromagnetic blocker to which a current is applied to induce an electromagnetic field, which deflects the electron beam of the SEM so that the electron beam no longer reaches the sample. In the SEM, the blocker may be a shutter configured to cut off the path of the electron beam of the SEM in order to perform blocking. In the SEM, the blocker may block for a time determined based on a dissipation time of charge dissipation.

[0017] In the SEM, the controller may include circuitry for determining a next unit area to be scanned, wherein the next unit area is at least a threshold distance from the scanned unit area, and the next unit area is selected to mitigate distortion caused by charge from the scanned unit area, so that the blocked unit area separates the scanned unit area from the next unit area. In the SEM, the blocker may be configured to block a predetermined pattern in the sample, the predetermined pattern including any of the following: a line pattern parallel to an edge of the scanned area, a line pattern of diagonal lines in the scanned area, a circular pattern, or a random pattern. In the SEM, the blocking layer may be positioned between the electron source and the scanning deflector.

[0018] According to some embodiments of the present disclosure, a non-volatile computer-readable medium is provided, which stores an instruction set, which can be executed by at least one processor of a computer system to enable the computer system to perform a method for service processing, the method comprising: providing a sample having a scanning area, wherein the sample is determined to have multiple unit areas; scanning a unit area among the multiple unit areas; and blocking a unit area adjacent to the scanned unit area.

[0019] In a non-transitory computer readable medium, the set of instructions can be executed by at least one processor of a computer system to cause the computer system to further perform: determining whether any unit area to be scanned remains on the sample; in response to determining that any unit area to be scanned remains on the sample, scanning a next unit area determined to be outside the dissipation area associated with the scanned unit area; and blocking unit areas adjacent to the next unit area. In the non-transitory computer readable medium, the scanned unit area is a single pixel or a plurality of pixels of a scanned image before scanning the next unit area.

[0020] According to some embodiments of the present disclosure, a method for scanning a sample using a scanning electron microscope (SEM) is provided. The method may include: scanning a first set of positions using the SEM, each position in the first set of positions being physically separated by at least a threshold distance; and scanning a second set of positions using the SEM in a time period after scanning the first set of positions, the positions of the second set of positions being within a threshold distance of the positions of the first set of positions. In the method, the time period enables the charge generated from scanning the first set of positions to be fully dissipated so as to reduce the distortion caused by the charge scanning of the positions within the threshold distance. In the method, each position in the first set of positions may be arranged diagonally with respect to each other. In the method, each position in the second set of positions may be arranged diagonally with respect to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1is a schematic diagram illustrating an exemplary electron beam inspection (EBI) system according to some embodiments of the present disclosure.

[0022] Figure 2 is a schematic diagram showing an exemplary electron beam tool according to some embodiments of the present disclosure, which may be Figure 1 Portion of an exemplary electron beam inspection (EBI) system.

[0023] Figure 3 is a schematic diagram showing a top view of a reference sample with a rectangular scanning grid according to some embodiments of the present disclosure.

[0024] FIG. 4A to FIG. 4L is a diagram showing some embodiments of the present disclosure Figure 3 Schematic diagram of a top view of a reference sample that has undergone Figure 2 FIG. 2 is an exemplary scanning process performed by an exemplary electron beam tool.

[0025] FIG. 5A to FIG. 5C is a diagram showing some embodiments of the present disclosure Figure 3 Schematic diagram of a top view of a reference sample that has undergone Figure 2 Another exemplary scanning process performed by an exemplary electron beam tool of FIG.

[0026] FIG. 6A to FIG. 6I is a diagram showing some embodiments of the present disclosure Figure 3 Schematic diagram of a top view of a reference sample that has undergone Figure 2 Another exemplary scanning process performed by an exemplary electron beam tool of FIG.

[0027] Figure 7 is a flow chart illustrating an exemplary method of scanning and blocking a sample using a SEM, according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0028] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, in which the same numbers in different drawings represent the same or similar elements unless otherwise specified. The implementations set forth in the following description of exemplary embodiments do not represent all implementations according to the present invention. Instead, they are merely examples of apparatus and methods according to aspects related to the present invention as described in the appended claims. For example, although some embodiments are described in the context of using a scanning electron microscope (SEM) to generate wafer images and defect detection, the present disclosure is not limited thereto. Other types of microscopes, such as a transmission electron microscope (TEM) and a scanning tunneling microscope (STM) may also be similarly applied.

[0029] Increasing the computing power of electronic devices while reducing the physical size of the devices can be achieved by significantly increasing the packaging density of circuit components such as transistors, capacitors, diodes, etc. on IC chips. For example, in a smartphone, an IC chip (the size of a thumbnail) can include more than 2 billion transistors, each of which is less than 1 / 1000 the size of a human hair. Not surprisingly, semiconductor IC manufacturing is a complex process with hundreds of individual steps. Even an error in one step has the potential to greatly affect the functionality of the final product. Even a single "fatal defect" can cause device failure. The goal of the manufacturing process is to increase the overall yield of the process. For example, to obtain a 75% yield for a 50-step process, the yield of each step must be greater than 99.4%, and if the yield of a single step is 95%, the yield of the entire process will drop to 7%.

[0030] At various steps in the semiconductor manufacturing process, pattern defects may appear on at least one of the wafer, chip or mask, which may cause the manufactured semiconductor device to fail, thereby greatly reducing the yield rate. As semiconductor device sizes continue to shrink (with any defects), identifying defects becomes more challenging and costly. Currently, engineers in semiconductor production lines typically spend hours (sometimes even days) to identify the locations of small defects to minimize their impact on the final product.

[0031] Conventional optical inspection techniques are ineffective in detecting small defects, such as nanoscale defects. To meet the needs of the semiconductor industry, advanced electron beam inspection (EBI) tools such as scanning electron microscopes with high resolution and large depth of focus have been developed. Although SEM plays an important role in small defect detection for semiconductor wafers, inspection of semiconductor wafers using electron beams involves scanning electron microscopes (SEMs) on samples (e.g. Figure 3 Charge is deposited at a specific location on a sample W in the wafer (e.g., a unit area (or pixel) on the sample), such as pixel 1. However, this charge may affect the imaging of subsequent adjacent pixels (e.g., pixels 1B and 1C), thereby causing distortion in the imaging of the wafer W. Therefore, this distortion may reduce the accuracy of the image, thereby affecting the ability to detect and analyze features on the image.

[0032] For example, as the electron beam scans across the sample (e.g., from left to right), a charge begins to build up on the surface on which the electron beam lands (e.g., the surface of the sample or the surface of a feature on the sample). As the charge builds up, an electric field also builds up, affecting the trajectory of electrons emitted from the sample (e.g., secondary electrons, backscattered electrons, etc.). This change in the trajectory of the emitted electrons can affect the number of emitted electrons detected by the detector, resulting in a lower quality and less accurate SEM image. For example, a charge can build up on the first pixel being scanned, and the resulting electric field can affect the electrons emitted from an adjacent pixel as the adjacent pixel is scanned, resulting in fewer electrons emitted from the adjacent pixel reaching the detector, and further resulting in a lower quality and less accurate image of the adjacent pixel.

[0033] The accumulated charge eventually dissipates; that is, after a sufficient amount of time, the accumulated charge is conducted away from the scanned pixel. Figure 3 In FIG. 1 , pixels 1A to 3C appear in a row on the sample. Some embodiments of the present disclosure take this dissipation effect into account and provide a method for scanning a unit area of ​​the sample (e.g. Figure 3 The process of scanning pixel 1A of sample W in the image and blocking the unit area (e.g., pixel 1A) adjacent to the scanned unit area (e.g., pixel 1B). The blocked unit area 1B has a distance that falls within the charged area (derived from the scanning of unit area 1A), so the unit area 1B is not scanned at this time. Instead of scanning unit area 1B, the unit area outside the charged area (e.g., unit area 1C) is scanned so that the dissipated charge does not affect the scan. After the first round of scanning the sample, some pixels (e.g., pixels 1A and 1C) are scanned and some pixels (e.g., pixels 1B and 2A) are blocked. Then, in subsequent scans, the blocked pixels are scanned after the charge associated with the scanned pixels 1A and 1C is dissipated. Compared to conventional SEM continuous scanning, some of the disclosed embodiments are capable of producing improved accuracy results and information to inspect samples for fine structures and nanoscale defects during the production of high-density integrated electronic devices such as computer processors, memories, and high-resolution sensor devices (such as digital camera sensors).

[0034] As used herein, unless otherwise specifically stated, the term "or" includes all possible combinations except those that are not feasible. For example, if the database is recorded to include A or B, then unless otherwise specifically stated or not feasible, the database may include A, B, or A and B. As a second example, if the database is recorded to include A, B, or C, then unless otherwise specifically stated or not feasible, the database may include A, or B, or C, or A and B, or A and C, or B and C, or A, B, and C.

[0035] Reference now Figure 1, which schematically illustrates an exemplary electron beam inspection system according to some embodiments of the present disclosure. Figure 1 As shown, the electron beam inspection system 100 includes a main chamber 101, a load / lock chamber 102, an electron beam tool 104, an equipment front end module 106, and a user interface 109. The electron beam tool 104 is located in the main chamber 101. The equipment front end module 106 includes a first loading port 106a and a second loading port 106b. The equipment front end module 106 may include additional loading ports. The first loading port 106a and the second loading port 106b receive a wafer box containing a wafer (e.g., a semiconductor wafer or a wafer made of other materials) or a sample (wafers and samples are collectively referred to as "wafers" hereinafter) to be inspected. One or more robotic arms (not shown) in the equipment front end module 106 transfer the wafer to the load / lock chamber 102. The load / lock chamber 102 is connected to a load / lock vacuum pump system (not shown), which removes gas molecules in the load / lock chamber 102 to reach a first pressure below atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) transfer the wafer from the load / lock chamber 102 to the main chamber 101. The main chamber 101 is connected to a main chamber vacuum pump system (not shown) that removes gas molecules in the main chamber 101 to reach a second pressure lower than the first pressure. After reaching the second pressure, the electron beam tool 104 controlled by the user using the user interface 109 inspects the wafer.

[0036] Reference now Figure 2 , which schematically illustrates an exemplary electron beam tool according to some embodiments of the present disclosure, which tool may be Figure 1 A portion of an exemplary electron beam tool 104 is shown. Figure 2 As shown, the electron beam tool 104 includes a motorized stage 400 and a wafer holder 402 supported by the motorized stage 400 to hold a wafer 403 to be inspected. The wafer 403 may be referred to as a sample. The electron beam tool 104 also includes an objective lens assembly 404, an electron detector 406 (including an electron sensor surface), an objective lens aperture 408, a condenser lens 410, a beam limiting aperture 412, a gun aperture 414, a blocker 424, an anode 416, and a cathode 418. In some embodiments, the objective lens assembly 404 may include a modified swinging objective delayed immersion lens (SORIL) including a pole piece 404a, a control electrode 404b, a deflector 404c, and an excitation coil 404d. The electron beam tool 104 may additionally include an energy dispersive X-ray spectrometer (EDS) detector (not shown) to characterize the material on the wafer.

[0037] By applying a voltage between the anode 416 and the cathode 418, a primary electron beam 420 is emitted from the cathode 418. The primary electron beam 420 passes through a blanker 424 and then passes through the gun aperture 414 and the beam limiting aperture 412, both of which can determine the size of the electron beam entering the condenser lens 410, which is located below the beam limiting aperture 412. The position of the blanker 424 in the electron beam tool 104 can be anywhere between the beam limiting aperture 412 and the sample wafer 403, depending on the needs of a particular measurement.

[0038] The blocker 424 may be a shutter, an electromagnetic deflector, or a purely electrostatic deflector, etc. In some embodiments, the shutter is mechanically moved or controlled by, for example, an electromagnetic field generated by a current-carrying coil to intercept the primary electron beam 420, so that the primary electron beam 420 cannot pass through the blocker 424 and reach the sample wafer 403. In some embodiments, the electromagnetic deflector uses a magnetic field generated by a permanent magnet or an electromagnet to control the deflection of the primary electron beam 420, so that the electron beam 420 no longer reaches the sample wafer 403. In some embodiments, the purely electrostatic deflector uses an electric field generated by opposite plates carrying opposite charges to control the deflection of the primary electron beam 420, so that the electron beam 420 no longer reaches the sample wafer 403.

[0039] The condenser lens 410 focuses the primary electron beam 420 before the primary electron beam 420 enters the objective lens aperture 408 to set the size of the primary electron beam 420 before entering the objective lens assembly 404. The deflector 404c deflects the primary electron beam 420 to facilitate beam scanning on the wafer 403. For example, during the scanning process, the deflector 404c can be controlled to deflect the primary electron beam 420 to different positions on the top surface of the wafer 403 at different time points in sequence to provide data for image reconstruction of different parts of the wafer 403. Moreover, the deflector 404c can also be controlled to deflect the primary electron beam 420 to different sides of the wafer 403 at a specific position at different time points to provide data for stereoscopic image reconstruction of the wafer structure at that position. Furthermore, in some embodiments, the anode 416 and the cathode 418 may be configured to generate multiple primary electron beams 420, and the electron beam tool 104 may include multiple deflectors 404c to simultaneously project the multiple primary electron beams 420 onto different portions / sides of the wafer 403 to provide data for image reconstruction of different portions of the wafer 203.

[0040] The excitation coil 404d and the pole piece 404a generate a magnetic field that starts at one end of the pole piece 404a and ends at the other end of the pole piece 404a. A portion of the wafer 403 scanned by the primary electron beam 420 may be immersed in the magnetic field and may be charged, which in turn generates an electric field. The electric field reduces the impact energy of the primary electron beam 420 near the surface of the wafer 403 before it collides with the wafer 403. The control electrode 404b, which is electrically isolated from the pole piece 404a, controls the electric field on the wafer 403 to prevent micro-arching of the wafer 403 and ensure proper beam focusing.

[0041] The secondary electron beam 422 may be emitted from the portion of the wafer 403 that receives the primary electron beam 420. The secondary electron beam 422 may form a beam spot on the sensor surface of the electron detector 406. The electron detector 406 may generate a signal (e.g., a voltage, a current, etc.) to represent the intensity of the beam spot and provide the signal to a processing system (not shown). The intensity of the secondary electron beam 422 and the beam spot generated may vary according to the external or internal structure of the wafer 403. Moreover, as described above, the primary electron beam 420 may be projected onto different locations on the top surface of the wafer 403 to generate secondary electron beams 422 (and the beam spots generated) of different intensities. Therefore, by mapping the intensity of the beam spot with the location of the wafer 403, the processing system may reconstruct an image reflecting the internal or external structure of the wafer 403. Once the electron beam tool 104 obtains a wafer image, the wafer image may be sent to a computer system (not shown).

[0042] Figure 3 is a schematic diagram showing a top view of a reference sample with a rectangular scanning grid according to some embodiments of the present disclosure. Figure 3 In the top surface of the sample wafer W, it is shown that: Figure 2 The scanning area SA of an exemplary SEM is Figure 2 An exemplary SEM scan pattern of a rectangular grid. Figure 3The rectangular grid shown is an 8×9 matrix rectangular grid with 8 rows and 9 columns of unit areas. The unit area or pixel can cover a portion of one or more dies and is designed for scanning and blocking purposes. Each unit area or pixel has an exemplary area of ​​1nm×1nm. Each unit area is marked with numbers and letters, for example, the unit area of ​​the 1st row and the 1st column is marked as 1A. The unit area located in the 8th row and the 9th column is marked as 24C. In this way, all unit areas in the grid are marked for the convenience of describing the scanning pattern of the SEM. In other embodiments, the grid can be an m×n matrix rectangular grid, where m and n are natural numbers. In addition, the shape of the grid can be rectangular, square, circular, elliptical, pentagonal, hexagonal, or any polygon. In order to better cover the disc-shaped sample W, the grid can be circular. To explain the scanning, a rectangular grid SA is used.

[0043] exist Figure 4A In FIG. 1 , during scanning of a sample W, the SEM emits an electron beam that interacts with a first unit area 1A of a scanning area or grid SA. During this scan, the electron beam interacts with the unit area 1A for a certain time and does not interact or interacts minimally with surrounding areas. During or after the scan, the charge accumulated on the unit area 1A and any surrounding areas is dissipated, which involves the charge being conducted away from the charged areas associated with the unit area 1A. The distance on the sample required for this conduction is the dissipation distance L ( Figure 4B ). Distance L is a threshold distance between successively scanned cell regions and is selected to mitigate distortion caused by charge from previously scanned nearby cell regions so that the blocked cell regions separate the scanned cell region and the next cell region to be scanned by a distance equal to or greater than the threshold distance. Thus, after scanning cell region 1A, the next cell region to be scanned is located outside the dissipation region (located at or greater than the distance L from the scanned cell region 1A), for example, the next cell region to be scanned may not be located Figure 4B The dissipation region is defined by the dashed circle in FIG. The dissipation region is determined based on the intensity of the electron beam interacting with the unit area 1A and the duration of such interaction. That is, when a higher electron beam intensity is used or when the electron beam interacts with the unit area for a longer duration, a larger dissipation region may appear, thereby generating a stronger electric field and increasing the range over which the electric field may have a negative effect.

[0044] Although it is preferred that the next cell region is outside the determined dissipation region to minimize any charge distortion, it is understood that some implementations may scan the next cell region that is not adjacent to the previously scanned cell region and that falls within the dissipation region. Figure 4BAlthough cell region 7A may have some charge / dissipation effects originating from the scanning of cell region 1A, it can be determined that these effects are not sufficient to cause corresponding charge distortion.

[0045] Referring to the scanning of sample W, scanning and blocking can be performed in organized batches of unit areas. Batches can be collections of unit areas in rows or columns. For example, FIG. 4A to FIG. 4L In the embodiment described in , each batch of unit regions corresponds to a different column. As shown in the figure, in the case where the batch is a column of unit regions, the scan can start from the unit region 1A of the first batch, and then scan down the column, and then use a blocker (e.g., Figure 2 The electron beam tool then scans the next unit area 10A, which is separated from the scanned unit area 10A by a distance greater than or equal to the dissipation distance L. In this way, after scanning the unit area 10A, the electron beam tool blocks the unit areas 13A and 16A ( Figure 4C ). Then, in Figure 4C In the embodiment, the electron beam tool scans the cell region 19A. Since the cell region 22A is adjacent to the scanned cell region 19A and is separated by a distance less than the dissipation distance L, the cell region 22A is blocked by the electron beam tool.

[0046] Then, in this way, a first round of scanning and blocking of the first batch of cell areas in the first column is completed, where some of the cell areas (i.e., 1A, 10A, and 19A) are scanned and some of the cell areas (4A, 7A, 13A, 16A, and 22A) are blocked to allow the charged areas around the cell areas 1A, 10A, and 19A to dissipate. After the charge dissipates or is substantially dissipated, the dissipation distance can be 0.1 μm to 5 μm, and the electron beam tool can revisit the first batch one or more times later to scan the blocked cell areas 4A, 7A, 13A, 16A, and 22A, so that the imaging information acquired from these cell areas is accurate and not distorted by the electric field of the accumulated charge.

[0047] like Figure 4D As shown, after scanning cell area 19A, the electron beam tool scans cell area 2A (which may be part of a second batch of cell areas - in this case, the column of cell areas associated with cell area 2A) that is outside the dissipation region associated with the scanned cell area 1A. Figure 4D As shown, cell regions 1B and 1C are located within the dissipative region. Because they are still located within the dissipative region, it can be appreciated that the columns associated with cell regions 1B and 1C can be blocked or skipped altogether.

[0048] In addition, although Figure 4D The size of the dissipation region is shown to be Figure 4B The size of the dissipation regions of the cells 1A and 1C are relatively the same, but it can be appreciated that the size of the dissipation regions and the dissipation distance L can be affected by the time that has passed to scan the cell region 1A. Therefore, the electron beam tool can take into account the time that has passed with respect to the dissipation regions when determining which cell region to scan next. To the extent that it has been determined that the dissipation regions have become smaller so that the charge has been sufficiently dissipated from the cell region 1C, the electron beam tool can scan the cell region 1C and proceed down the column associated with the cell region 1C.

[0049] Return to reference Figure 4D , although the figure shows that cell region 2A is the next cell region to be scanned after the scanning of cell region 19A, it is understood that any cell region outside the dissipation region associated with the scanned cell regions 1A, 10A, and 19A can be scanned. For example, cell region 20A or 23A can be scanned after cell region 19A because they are both outside the dissipation region associated with cell region 19A. Therefore, the electron beam tool can block and scan other cell regions in the column associated with cell region 20A or 23A.

[0050] exist Figure 4E In, use Figure 4B In the same manner as described above, after scanning the second batch of unit regions 2A, the electron beam tool blocks unit regions 5A and 8A and scans the next unit region 11A. Figure 4F As shown, use the above Figure 4C After scanning the cell area 11A, the electron beam tool blocks the cell areas 14A and 17A and scans the cell area 20A. After scanning the cell area 20A, the electron beam tool uses the method described above. Figure 4D A similar method as described in . For example, Figure 4G As shown, cell region 23A is blocked, and all cell regions in the column associated with cell regions 2B and 2C are blocked or skipped, and the electron beam scans the cell region 3A of the third batch. In a manner similar to that described above, as shown in FIG. Figure 4H As shown, after scanning unit area 3A, the electron beam tool blocks unit areas 6A and 9A, and then scans unit area 12A. After scanning unit area 12A, as shown in FIG. Fig. 4I As shown, the electron beam tool blocks cell regions 15A and 18A and then scans cell region 21A.

[0051] After scanning the cell region 21A, the cell region 24A and all the cell regions in the column associated with the cell regions 3B and 3C are within the range of the distance L and can be blocked or skipped. Then, after scanning the cell region 21A, as shown in FIG. Figure 4JAs shown, the electron beam tool returns to the first batch of cell areas (in this case, the first column associated with cell area 1A) to scan the unscanned cell area 4A adjacent to the previously scanned first cell area 1A because the charge from cell area 1A has dissipated sufficiently over time to mitigate any threshold level of charge distortion for the imaged cell area 4A.

[0052] For similar reasons explained above, Figure 4K As shown, in Figure 4J After scanning unit area 4A, the electron beam tool blocks unit areas 7A and 10A, and the electron beam scans unit area 13A ( Figure 4K ). The process continues so that cell area 22A is scanned, after which the electron beam tool sequentially scans cell areas 5A, 14A, and 23A of the second batch and cell areas 6A, 15A, and 24A of the third batch. The electron beam tool can then move back to the first column of cell areas and scan cell areas 7A and 16A of the first batch, after which the electron beam tool scans cell areas 8A and 17A of the second batch and cell areas 9A and 18A of the third batch. After completing the scan of column A associated with cell areas 1A, 2A, and 3A, the scanning and blocking process can be moved so as to be in the same manner as described above with respect to Figures 4A to 4K The B columns (e.g., columns associated with cell regions 1B, 2B, and 3B) are scanned in a manner similar to that described above. After scanning the cell regions in column B, the electron beam tool can then move to scan and block column C (e.g., columns associated with cell regions 1C, 2C, and 3C), which completes the Figure 4L As shown. In this way, the entire scanning area or grid SA is scanned. After the scan is completed, the processor or controller of the SEM system can be used with or without the user to Figure 1 The information obtained is analyzed without intervention of the user interface 109 in the process.

[0053] Figure 5A , Figure 5B and Figure 5C is a diagram showing some embodiments of the present disclosure Figure 3 Schematic diagram of the top view of the reference sample, which passes through the Figure 2 The exemplary electron beam tool of performs different scanning phases of column-to-row scanning. The distance L' is a distance greater than a threshold between successively scanned cell regions, which is selected to mitigate charge-induced distortion from previously scanned nearby cell regions, so that the blocked cell regions separate each cell region to be scanned and the next cell region to be scanned by a distance greater than the threshold distance. Figure 5AIn FIG. 1 , during scanning of the sample W, the electron beam tool emits an electron beam that interacts with a first unit area 1A of the scanning area or grid SA. During this scan, the electron beam interacts with most of the unit areas 1A or the entire unit area 1A for a certain time. During or after the scan, the charge accumulated on the unit area 1A begins to dissipate by being conducted away from the unit area of ​​the sample W. The distance on the sample required for this conduction is the dissipation distance L'( Figure 5B ). Therefore, after scanning the unit region 1A, the next unit region to be scanned may be located at a distance L' from the scanned unit region 1A or outside the distance L', that is, the next unit region to be scanned may not be located at Figure 5B The dissipative region is annotated with a dashed line.

[0054] like Figure 5B As shown, after scanning cell area 1A, the electron beam tool blocks cell areas 4A, 7A, and 10A by deflecting the electron beam from these cell areas because each of these blocked cell areas falls within the dissipation region of the dashed circle associated with the dissipation distance L'. The electron beam then scans the next cell area 16A, which is separated from the scanned cell area 1A by the dissipation distance L'. In this way, after scanning cell area 16A, cell areas 19A and 22A are blocked, and all cell areas in columns 2 to 5 are blocked or skipped ( Figure 5C ).

[0055] Then, the electron beam scans the next unit area 2C. After scanning the unit area 2C, the electron beam tool blocks the unit areas 5C, 8C, 11C and 14C and scans the unit area 17C ( Figure 5C ). After scanning unit area 17C, unit areas 20C and 23C are blocked, and all unit areas in columns 7 to 9 are within the range of distance L' and can be blocked or skipped, and they can be scanned later. Then, the electron beam returns to the first column to continue scanning the next unit area (for example, unit area 4A). In this way, the first round of scanning of the scanning area is completed by scanning unit areas 1A, 16A, 2C, and 17C.

[0056] FIG. 6A to FIG. 6I is a diagram showing some embodiments of the present disclosure Figure 3 Schematic diagram of a top view of a reference sample that has undergone Figure 2 An exemplary electron beam tool of FIG. 1 is shown with different stages of scanning by diagonal scanning at a dissipation distance L. Fig. 6AIn the embodiment, the electron beam tool emits an electron beam that interacts with a first unit area 1A of a scanning area or grid SA during scanning of a sample W. During the scanning, the electron beam interacts with most of the unit areas 1A or the entire unit area 1A for a certain time.

[0057] During or after scanning, the charge accumulated on the unit area 1A begins to dissipate by being conducted away from the unit area of ​​the sample W. The distance on the sample required for this conduction is the dissipation distance L ( Figure 6B ). Therefore, after scanning the cell area 1A, the electron beam tool scans the cell area 11A located outside the dissipation region. In the scanning pattern starting from the cell area 1A and then diagonally to the lower right corner of the grid SA, the cell areas 4B and 7C are wholly or partially within the range of the distance L from the cell area 1A and are blocked by the blocker (e.g., Figure 2 Then, the electron beam scans the next unit area 11A, which is separated from the scanned unit area 11A by more than the dissipation distance L. In this way, after scanning the unit area 11A, the electron beam tool blocks the unit areas 14B and 17C ( Figure 6C ). Then, the electron beam scans the next unit area 21A. After scanning the unit area 21A, the electron beam tool blocks the unit area 24B and then scans the unit area 2A ( Fig.6D ). It will be appreciated that between blocking of cell area 24B and scanning of cell area 2A, the electron beam tool may block cell areas 1B, 4C, 8A, 11B, 14C, 18A, 21B, 24C, 1C, 5A, 8B, 11C, 15A, 18B, and 21C.

[0058] After scanning the cell area 2A, the electron beam tool blocks at least the cell areas 5B and 8C because these cell areas fall within the range of the distance L from the cell area 2A. Then, the electron beam scans the cell area 12A ( Fig. 6E ). After scanning unit area 12A, the electron beam tool can block unit areas 2B, 5C, 9A, 12B, 15C, 2C, 6A, 9B and 12C or skip them all and continue to scan the next unit area.

[0059] Then, the electron beam scans the unit area 3A ( Fig. 6F ).exist Figure 6G In the example, after scanning unit area 3A, the electron beam tool scans unit area 19A ( Figure 6G ). It will be appreciated that the electron beam tool may scan cell region 10A instead of cell 19A and then block one or more cell regions that are diagonal to cell 10A.

[0060] refer to Figure 6H, after scanning cell area 19A, the electron beam tool may block cell areas 22B, 16A, 19B, 22C, 13A, 16B, 19C, and 23A because these cell areas are within the range of distance L and scanning these cell areas will result in distorted information. It will be appreciated that instead of blocking these cell areas (i.e., cell areas 22B, 16A, 19B, 22C, 13A, 16B, 19C, and 23A), the electron beam tool may skip these cells altogether before moving to scan the next cell area. The electron beam tool then scans cell area 10A ( Figure 6H ). Fig. 6E In the same manner, the electron beam tool is in the scanning unit area 20A ( Fig.6I ), at least unit areas 13B and 16C are blocked before the first round of scanning of the scanning area SA is completed. Therefore, when the first round of scanning of the scanning area SA is completed, unit areas 1A, 10A, 19A, 2A, 11A, 20A, 3A, 12A and 21A are scanned, and all other unit areas in the scanning area or grid SA are blocked (some unit areas can be skipped altogether). The above embodiment shows a rectangular grid. For those of ordinary skill in the art, the grid shape can be any shape including the following items: square, pentagon, hexagon, polygon, circle, ellipse and a mixture of various shapes.

[0061] As described above, a plurality of unit areas of the scanning area can be organized in batches by unit areas provided in rows or columns, and the scanned unit areas and the blocked unit areas are located in the unit areas of the first batch. After scanning and blocking the unit areas of the first batch, the electron beam tool blocks the unit areas of the second batch adjacent to the first batch; and the electron beam tool scans and blocks the unit areas in the unit areas of the third batch, the unit areas of the third batch are not adjacent to the unit areas of the first batch and are at least a threshold distance from the unit areas of the first batch to reduce the distortion caused by the charge of the scanned unit areas from the first batch. After scanning and blocking the unit areas of the third batch or after the dissipation time threshold, the electron beam tool returns to the unit areas of the first batch to scan the unit areas that were not previously scanned, to reduce the distortion caused by the charge of the unit areas of the first batch previously scanned. In this way, the unit areas to be scanned and blocked can be flexibly controlled to adapt to different purposes (e.g., the efficiency or time consumption of scanning, and the image quality level of the final image).

[0062] Alternatively, the method includes scanning a first set of positions using a SEM. Each position in the first set of positions is physically separated by at least a threshold distance. In some embodiments, the method also includes scanning a second set of positions using the SEM within a time period after scanning the first set of positions. In some embodiments, the positions in the second set of positions are located within a threshold distance of the positions in the first set of positions. The time period enables the charge generated from scanning the first set of positions to be sufficiently dissipated so as to reduce distortion caused by the charge of the scanning of the positions within the threshold distance. In some embodiments, each position in the first set of positions is arranged diagonally with respect to each other. In some embodiments, each position in the second set of positions is arranged diagonally with respect to each other.

[0063] Reference now Figure 7 , Figure 7 is a flow chart illustrating an exemplary method for scanning a sample using a charged particle tool according to some embodiments of the present disclosure. The method may be performed by a charged particle beam tool, such as an electron beam tool (e.g., Figure 2 Electron beam tool 104).

[0064] In step S710, a sample is provided in an electron beam tool. The sample (e.g., Figure 2 Sample 403 or Figure 3 Samples W) include wafers made of silicon, silicon dioxide, germanium, and silicon germanium, with or without patterns formed thereon by any method including UV, DUV, and EUV lithography methods. The samples may include areas having conductive, semiconductive, or insulating properties. In addition, the samples may or may not be treated by sputtering a layer of a highly conductive material (e.g., gold or silver) thereon.

[0065] In an electron beam tool, the top surface of the sample can be logically divided into many unit areas, such as pixels (e.g., Figure 3 ). The electron beam of the electron beam tool scans each unit area in a short period of time. In this example, the unit area or pixel is a 1nm×1nm square area of ​​the sample, but it should be understood that the unit area can be a defined area of ​​any size or any shape, including rectangular, circular or polygonal, etc.

[0066] In step S720, the electron beam tool scans one or more unit regions of the sample. During the scan, the electron beam interacts with the material on the surface of the unit region of the sample. The longer the electron beam interacts with the unit region, the more charge buildup occurs in the area surrounding the unit region due to the interaction. Optionally, in step S720, a timestamp associated with the scan of the unit region may be provided, which allows the electron beam tool to determine when to revisit the unit regions surrounding the scanned unit region so as to minimize the impact that charge distortion from previously scanned unit regions may have on surrounding unit regions.

[0067] The more charge buildup occurs in the area surrounding the cell area, the longer it takes for the charge to dissipate from that area. Additionally, the type of sample material can affect charge dissipation, as each sample material can have distance dissipation characteristics and time dissipation characteristics. These characteristics can vary depending on the material used. In some examples, the distance for the accumulated charge to be conducted away from the scanned cell area of ​​the sample is about 0.1 μm to 5 μm, which is called the dissipation distance, and the time required for this effect is called the dissipation time.

[0068] In step S730, the electron beam tool blocks the unit area adjacent to the scanned unit area of ​​the sample. Taking into account the dissipation distance and dissipation time required to conduct the accumulated charge away from the scanned unit area of ​​the sample, the next area to be scanned will be located at a distance equal to or greater than the dissipation distance from the unit area scanned in step S720. In order to achieve the effect of not scanning the area between the scanned unit area in step S720 and the next unit area to be scanned, the electron beam tool is equipped with a component called a blocker (e.g., Figure 2 The blocker 424 may be a shutter, an electromagnetic field deflector, or a pure electrostatic deflector, etc. The blocker may deflect the electron beam so that the electron beam no longer reaches the sample, so that the area between the unit area scanned in step S720 and the unit area to be scanned is not scanned by the electron beam.

[0069] As mentioned above, it will be appreciated that more than one cell region may be blocked (e.g., Figure 4B The number of blocked unit regions may depend on the amount of time the electron beam interacts with the scanned unit region in step S720. The amount of time may affect the blocking time and the blocking distance, both of which may be used to determine the blocking time and the corresponding one or more blocked unit regions, respectively. That is, the blocking time is determined by the dissipation time, and the unit region for blocking is determined by the dissipation distance, so that the blocking distance is greater than the dissipation distance and the blocking time is greater than the dissipation time.

[0070] In step S750, the electron beam tool determines whether there are any unscanned unit areas in the sample. If there are unscanned unit areas after step S730 of blocking the unit areas, the method proceeds to S770, where the electron beam tool scans another unit area outside the dissipation area associated with the previously scanned unit area (for example, the unit area scanned in step S720). In this way, the scanning and blocking of the unit area can be repeated until the area of ​​interest of the sample is completely scanned, at which point in step S750 the electron beam tool determines that there are no remaining unscanned areas. The process of scanning the sample then ends in step S760. Optionally, after step S750, the method further includes the following process: reconstructing the entire image by using sub-images generated using various scanned unit areas to provide an image of the sample. To this end, the sequence of images can be mapped into a logical arrangement of multiple unit areas and the order in which the multiple unit areas are scanned. For example, using FIG. 4A to FIG. 4J As a reference, the first sub-image (the sub-image associated with the unit area 1A) and the tenth sub-image (the sub-image associated with the unit area 4A) can be spliced ​​together using the scanning order of the unit area. In addition, reconstruction is performed by using at least one of interpolation, sparse sampling or simulation.

[0071] The embodiments may be further described using the following terms:

[0072] 1. A method for scanning a sample by a charged particle beam tool, comprising:

[0073] providing a sample having a scan area, wherein the sample is determined to have a plurality of unit areas;

[0074] scanning a cell region among a plurality of cell regions; and

[0075] A first cell region adjacent to the scanned cell region is blocked.

[0076] 2. The method according to item 1, further comprising:

[0077] determining whether there are any unit areas on the sample to be scanned;

[0078] In response to determining that there are any unit areas to be scanned on the sample,

[0079] Scanning a next unit area that is greater than a predetermined distance from the scanned unit area; and

[0080] A second cell region adjacent to the next cell region to be scanned is blocked.

[0081] 3. A method according to item 2, wherein the predetermined distance is based on a dissipation area associated with the scanned cell area.

[0082] 4. The method according to item 2, further comprising: blocking a third unit region adjacent to the blocked first unit region before scanning the next unit region.

[0083] 5. The method according to item 1, wherein the blocked first unit region includes a plurality of unit regions.

[0084] 6. The method according to any one of items 1 to 5, wherein the blocked first cell region is adjacent to the scanned cell region in the X direction.

[0085] 7. The method according to any one of items 1 to 5, wherein the blocked first unit region is adjacent to the scanned unit region in the Y direction.

[0086] 8. A method according to item 1, wherein the scanned unit area is a single pixel of the scanned image.

[0087] 9. The method according to item 1, wherein the blocked first unit area is a single pixel.

[0088] 10. The method according to item 1, wherein the blocked first unit area is a plurality of pixels.

[0089] 11. A method according to item 1, wherein the scanned unit area is a plurality of pixels of the scanned image.

[0090] 12. The method according to any one of items 1 to 11, wherein blocking a first unit region adjacent to the scanned unit region further comprises:

[0091] A current is applied to the electromagnetic blanker so that the electromagnetic field generated by the blanker deflects the charged particle beam of the charged particle beam tool so that the charged particle beam no longer reaches the sample.

[0092] 13. The method according to any one of items 1 to 11, wherein blocking a first unit region adjacent to the scanned unit region further comprises:

[0093] The shutter is moved to intercept the path of the charged particle beam of the charged particle beam tool so that the charged particle beam no longer reaches the sample.

[0094] 14. The method according to any one of items 1 to 13, wherein scanning and blocking are determined based on a dissipation time for charge dissipation in the scanned cell area.

[0095] 15. A method according to any one of items 1 to 13, wherein scanning and blocking are performed on a predetermined pattern in the sample.

[0096] 16. The method according to item 15, wherein the predetermined pattern is one of: a line pattern parallel to an edge of the scanned area, a line pattern of diagonal lines in the scanned area, or a circular pattern.

[0097] 17. The method according to any one of items 1 to 15, wherein scanning and blocking are performed on the plurality of unit areas until all unit areas are scanned.

[0098] 18. The method according to item 17 also includes: reconstructing an image of the sample using sub-images corresponding to the scanned multiple unit areas.

[0099] 19. A method according to item 18, wherein the reconstruction is performed by using at least one of interpolation, sparse sampling or simulation.

[0100] 20. A method according to any one of items 1 to 19, wherein the plurality of unit areas of the scanning area are organized into batches of unit areas provided in rows or columns, and

[0101] The scanned cell region and the blocked cell region are in the first batch of cell regions.

[0102] 21. The method according to item 20, wherein after scanning and blocking the first batch of cell areas:

[0103] Blocking or skipping a region of cells of a second batch adjacent to a first batch; and

[0104] A cell region of a third batch that is at least a threshold distance from the first batch is scanned and blocked to mitigate charge-induced distortion from the scanned cell region of the first batch.

[0105] 22. The method according to item 20 further includes: after a dissipation time threshold, returning to the first batch of cell regions to scan previously unscanned cell regions, thereby mitigating distortion caused by charges from previously scanned first batch of cell regions.

[0106] 23. A charged particle beam system comprising:

[0107] Charged particle sources;

[0108] a scanning deflector for scanning a charged particle beam emitted from the charged particle source over a scanning area of ​​a sample, wherein the sample is determined to have a plurality of unit areas;

[0109] a blocker for blocking the charged particle beam so that the charged particle beam no longer reaches the sample; and

[0110] a controller including circuit means for controlling said scanning deflector and said blanker,

[0111] Wherein, the controller is configured as:

[0112] scanning a cell region among a plurality of cell regions; and

[0113] A first cell region adjacent to the scanned cell region is blocked.

[0114] 24. The system according to item 23, wherein the controller is further configured to:

[0115] Determining whether there are any unit areas remaining on the sample to be scanned;

[0116] In response to determining that there are still unit areas remaining to be scanned on the sample,

[0117] Scanning a next unit area that is greater than a predetermined distance from the scanned unit area; and

[0118] A second cell region adjacent to the next cell region to be scanned is blocked.

[0119] 25. A system according to item 24, wherein the predetermined distance is based on a dissipation area associated with the scanned cell area.

[0120] 26. The system according to any one of clauses 24 and 25, wherein the controller is further configured to:

[0121] Before scanning the next cell region, a third cell region adjacent to the blocked first cell region is blocked.

[0122] 27. A system according to item 23, wherein the blocked first unit area includes multiple unit areas.

[0123] 28. A system according to any one of items 23 to 27, wherein the charged particle beam system is a scanning electron microscope (SEM).

[0124] 29. A system according to any one of items 23 to 28, wherein the charged particle beam is an electron beam.

[0125] 30. The system according to any one of items 23 to 29, wherein the blocked first cell region is adjacent to the scanned cell region in the X direction.

[0126] 31. A system according to any one of items 23 to 29, wherein the blocked first unit area is adjacent to the scanned unit area in the Y direction.

[0127] 32. A system according to item 23, wherein the scanned unit area is a single pixel of the scanned image.

[0128] 33. A system according to item 23, wherein the blocked first unit area is a single pixel.

[0129] 34. A system according to item 23, wherein the blocked first unit area is a plurality of pixels.

[0130] 35. A system according to item 23, wherein the scanned unit area is a plurality of pixels of the scanned image.

[0131] 36. A system according to any one of items 23 to 35, wherein the blocker is an electromagnetic blocker to which an electric current is applied to induce an electromagnetic field, which deflects the charged particle beam of the SEM so that the charged particle beam no longer reaches the sample.

[0132] 37. A system according to any one of items 23 to 35, wherein the blocker is a shutter configured to intercept the path of the charged particle beam of the SEM in order to perform the blockage.

[0133] 38. A system according to any one of items 23 to 37, wherein the blocker is configured to block for a time determined based on a dissipation time for charge dissipation.

[0134] 39. A system according to any one of items 23 to 37, wherein the controller includes a circuit device for determining a next cell area to be scanned, wherein the next cell area is at least a threshold distance away from the scanned cell area, and the next cell area is selected to reduce distortion caused by charge from the scanned cell area so that the blocked cell area separates the scanned cell area from the next cell area.

[0135] 40. A system according to any one of items 23 to 39, wherein the blocker is configured to block a predetermined pattern in the sample, the predetermined pattern comprising any one of: a line pattern parallel to an edge of the scanning area, a line pattern of diagonal lines in the scanning area, a circular pattern, or a random pattern.

[0136] 41. A system according to any one of items 23 to 40, wherein the blocker is positioned between the charged particle source and the scanning deflector.

[0137] 42. A non-transitory computer readable medium storing a set of instructions executable by at least one processor of a computer system to cause the computer system to perform a method for service processing, the method comprising:

[0138] providing a sample having a scanning area, wherein the sample is determined to have a plurality of unit areas;

[0139] scanning a unit area among the plurality of unit areas with a charged particle beam; and

[0140] Block cell regions adjacent to the cell region being scanned.

[0141] 43. The non-transitory computer readable medium of clause 42, wherein the set of instructions is executable by at least one processor of a computer system to cause the computer system to further perform:

[0142] Determining whether there are any unit areas remaining on the sample to be scanned;

[0143] In response to determining that there are still unit areas remaining to be scanned on the sample,

[0144] Scanning a next unit area which is away from the scanned unit area by a distance greater than a predetermined distance using a charged particle beam; and

[0145] Block the cell area adjacent to the next cell area.

[0146] 44. A non-transitory computer readable medium according to item 43, wherein the predetermined distance is based on a dissipation area associated with the scanned cell area.

[0147] 45. The non-transitory computer readable medium according to items 42 to 44, wherein the scanned unit area is a single pixel or a plurality of pixels of the scanned image before scanning the next unit area.

[0148] 46. ​​A method of scanning a sample by a charged particle beam system, the method comprising:

[0149] scanning a first unit area of ​​a first set of unit areas with a charged particle beam, each unit area of ​​the first set of unit areas being separated by more than a predetermined distance; and

[0150] A second cell region in a second set of cell regions is scanned a period of time after scanning a first cell region in the first set of cell regions, each cell region in the second set of cell regions being separated by more than the predetermined distance.

[0151] 47. A method according to item 46, wherein the predetermined distance is based on the size of the dissipative region associated with the unit area.

[0152] 48. A method according to any one of items 46 to 47, wherein the time period is based on a time for dissipating charges generated by the scanning of the first unit area.

[0153] It will be appreciated that the controller of the electron beam tool may use software to control the above functions. For example, the controller may assist in the scanning and blocking of the cell areas and the order in which the cell areas are scanned. In addition, the controller may automatically adjust the order in which the cell areas are scanned and blocked based on the characteristics of the wafer and the length of time the electron beam interacts with the wafer. The controller may send instructions for scanning the wafer (e.g., scanning Figure 7 The software may be stored on a non-transitory computer readable medium. Common forms of non-transitory media include, for example, a floppy disk, a floppy disk, a hard disk, a solid state drive, a magnetic tape or any other magnetic data storage medium, a CD-ROM, any other optical data storage medium, any physical medium with a pattern of holes, RAM, PROM and EPROM, cloud storage, Flash EPROM or any other flash memory, NVRAM, cache, registers, any other memory chip or cartridge, and networked versions thereof.

[0154] It will be further understood that various changes may be made by those skilled in the art to the details, materials and arrangements of components described and illustrated to explain the nature of the described embodiments without departing from the scope as expressed in the appended claims.

Claims

1. A charged particle beam system, comprising: Charged particle sources; a scanning deflector for scanning a charged particle beam emitted from the charged particle source over a scanning area of ​​a sample, wherein the sample is determined to have a plurality of unit areas; A blocker, used for blocking the charged particle beam so that the charged particle beam no longer reaches the sample; and a controller including circuit means for controlling said scanning deflector and said blanker, Wherein, the controller is configured as: scanning a unit area among the plurality of unit areas; as well as A first unit area adjacent to the scanned unit area and located within a dissipation region is blocked, the dissipation region being determined based on the intensity of the charged particle beam interacting with the scanned unit area and the duration of the interaction.

2. The system of claim 1, wherein the controller is further configured to: determining whether any unit area remains to be scanned on the sample; In response to determining that any unit area remains to be scanned on the sample, Scanning a next unit area that is greater than a predetermined distance from the scanned unit area; and A second cell region adjacent to the next cell region to be scanned is blocked.

3. The system of claim 2, wherein the predetermined distance is based on a dissipation area associated with the cell area being scanned.

4. The system of claim 2, wherein the controller is further configured to: Before scanning the next unit region, a third unit region adjacent to the blocked first unit region is blocked. The system according to claim 1 , wherein the blocked first unit area includes a plurality of unit areas.

6. The system of claim 1, wherein the charged particle beam system is a scanning electron microscope (SEM) and the charged particle beam is an electron beam. 7 . The system according to claim 1 , wherein the blocked first cell region is adjacent to the scanned cell region in an X direction. 8 . The system according to claim 1 , wherein the blocked first unit region is adjacent to the scanned unit region in the Y direction.

9. The system of claim 1, wherein the unit area scanned is a single pixel of the scanned image.

10. The system of claim 1, wherein the first unit area that is blocked is a single pixel.

11. The system according to claim 1, wherein the first unit area to be blocked is a plurality of pixels.

12. The system of claim 1, wherein the unit area scanned is a plurality of pixels of a scanned image.

13. A system according to claim 1, wherein the controller includes a circuit device for determining a next cell region to be scanned, wherein the next cell region is at least a threshold distance away from the cell region being scanned, and the next cell region is selected to reduce distortion caused by charge from the cell region being scanned, so that the blocked cell region separates the cell region to be scanned from the next cell region.

14. The system according to claim 1, wherein the blocker is an electromagnetic blocker to which a current is applied to induce an electromagnetic field, which deflects the charged particle beam of the charged particle beam system so that the charged particle beam no longer reaches the sample.

15. A non-transitory computer readable medium storing a set of instructions executable by at least one processor of a computer system to cause the computer system to perform a method for service processing, the method comprising: providing a sample having a scanning area, wherein the sample is determined to have a plurality of unit areas; scanning a unit area among the plurality of unit areas with a charged particle beam; as well as Cell regions adjacent to the scanned cell region and located within a dissipation region determined based on the intensity of the charged particle beam interacting with the scanned cell region and the duration of the interaction are blocked.

Images