System and method for scanning sample using multi-beam inspection device

Abstract

The present disclosure relates to systems and methods for scanning a sample using a multi-beam inspection device. A multi-beam tool includes a beam configuration system including a charged particle source configured to generate a primary beam of charged particles, a stage configured to hold a sample, and a deflector system located between the charged particle source and the stage configured to split the primary beam into an array of beams; wherein the beam configuration system is configured to provide a rotating beam configuration having a rotation angle determined based on a number of beams in rows of the beam array.

Description

[0001] Description of the case

[0002] This application is a divisional application of the Chinese invention patent application with application number 201980039657.X filed on June 7, 2019 and entitled “System and method for scanning a sample using a multi-beam inspection device”.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims priority to U.S. Application No. 62 / 684,138 filed on June 12, 2018, U.S. Application No. 62 / 787,227 filed on December 31, 2018, and U.S. Application No. 62 / 850,461 filed on May 20, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0005] Embodiments provided herein relate generally to inspection of samples using particle beam inspection devices, and more particularly, to systems and methods for scanning samples using multiple charged particle beams. Background Art

[0006] When manufacturing semiconductor integrated circuit (IC) chips, pattern defects or unwanted particles (residues) inevitably appear on the wafer or mask during the manufacturing process, thereby reducing the yield. For example, for patterns with smaller critical feature sizes that have been adopted to meet the ever-increasing performance requirements of IC chips, uninvited particles can be troublesome.

[0007] Pattern inspection tools with charged particle beams have been used to detect defects or uninvited particles. These tools typically use a scanning electron microscope (SEM). In an SEM, a primary electron beam with relatively high energy is decelerated so that it lands on a sample with a relatively low landing energy and is focused to form a detection spot thereon. Due to this focused detection spot of the primary electrons, secondary electrons will be generated from the surface. Secondary electrons may include backscattered electrons, secondary electrons, or Auger electrons generated due to the interaction of the primary electrons with the sample. By scanning the detection spot over the sample surface and collecting secondary electrons, the pattern inspection tool can acquire an image of the sample surface. Summary of the invention

[0008] Embodiments provided herein disclose a particle beam inspection apparatus, and more particularly, disclose an inspection apparatus using a multi-charged particle beam.

[0009] In some embodiments, a multi-beam tool is provided. The multi-beam tool includes a beam configuration system, the beam configuration system including: a charged particle source for generating a primary beam of charged particles, a stage for holding a sample, and a deflector system located between the charged particle source and the stage and configured to divide the primary beam into a beam array. The beam configuration system is configured to provide a rotation beam configuration having a rotation angle determined based on the number of beams in a row of the beam array.

[0010] In some embodiments, a multi-beam tool is provided. The multi-beam tool includes: a charged particle source for generating a primary beam of charged particles, a stage configured to hold a sample and configured to move in a first direction, and a deflector system located between the charged particle source and the stage. The deflector system is configured to: split the primary beam into n beams, where n is an integer and n≥2; rotate the n beams relative to the first direction so that the n beams are spaced apart along the first direction; deflect the n beams to simultaneously i) follow the movement of the stage, and ii) scan one or more groups of N scan lines on the surface of the sample.

[0011] In some embodiments, a multi-beam tool is provided. The multi-beam tool includes a beam configuration system, the beam configuration system including a charged particle source configured to generate a primary beam of charged particles, a stage configured to hold a sample and configured to move in a first direction, and a deflector system located between the charged particle source and the stage. The deflector system is configured to divide the primary beam into a beam array. The beam configuration system is configured to: deflect the beam array via the deflector system to i) scan a first set of scan lines in a field of view of the beam configuration system, and ii) follow the movement of the stage during the scanning of the first set of scan lines, wherein the first set of scan lines are spread over a first distance in a first direction; after the first set of scan lines are scanned, move the stage a first distance in the first direction; and deflect the beam array via the deflector system to i) scan a second set of scan lines in a field of view of the beam configuration system, and ii) follow the movement of the stage during the scanning of the second set of scan lines; and move the stage in the first direction when scanning the first and second sets of scan lines.

[0012] In some embodiments, a method for controlling multiple charged particle beams to scan a sample is provided. The method includes: generating a primary beam of charged particles by a multi-beam tool; dividing the primary beam into a beam array by the multi-beam tool; and rotating the beam array relative to the sample to be scanned by a rotation angle determined based on the number of beams in a row of the beam array by the multi-beam tool.

[0013] In some embodiments, a method for controlling multiple charged particle beams to scan a sample is provided. The method includes: moving the sample in a first direction by a multi-beam tool; generating a primary beam of charged particles by the multi-beam tool; dividing the primary beam into n beams by the multi-beam tool, where n is an integer and n≥2; rotating the n beams relative to the first direction so that the n beams are spaced apart along the first direction; deflecting the n beams by the multi-beam tool to simultaneously i) follow the movement of the sample, and ii) scan one or more groups of N scan lines on the surface of the sample.

[0014] In some embodiments, a method of controlling multiple charged particle beams to scan a sample is provided. The method includes: moving the sample in a first direction; generating a primary beam of charged particles by a multi-beam tool; dividing the primary beam into a beam array by the multi-beam tool; deflecting the beam array by the multi-beam tool to i) scan a first set of scan lines in a field of view of the multi-beam tool, and ii) follow the movement of the sample during the scanning of the first set of scan lines, wherein the first set of scan lines are spread over a first distance along a first direction; after the first set of scan lines are scanned, moving the sample by the multi-beam tool a first distance in the first direction; deflecting the beam array by the multi-beam tool to i) scan a second set of scan lines in the field of view of the multi-beam tool, and ii) follow the movement of the sample during the scanning of the second set of scan lines; and moving the sample by the multi-beam tool in the first direction while the first and second sets of scan lines are scanned.

[0015] In some embodiments, a non-transitory computer-readable medium having an instruction set stored therein is provided. The instruction set is executable by a controller coupled to a multi-beam tool to cause the controller to execute a method, the method comprising: instructing a beam configuration system of the multi-beam tool, by the multi-beam tool, to rotate a charged particle beam array relative to a sample to be scanned by a rotation angle determined based on the number of beams in a row of the beam array. The multi-beam tool generates a primary beam of charged particles and divides the primary beam into a charged particle beam array.

[0016] In some embodiments, a non-transitory computer-readable medium having a set of instructions stored thereon is provided. The set of instructions is executable by a controller coupled to a multi-beam tool to cause the controller to execute a method, the method comprising: instructing a sample stage of the multi-beam tool to move a sample in a first direction, the multi-beam tool generating a primary beam of charged particles and splitting the primary beam into n beams, wherein n is an integer and n≥2; instructing a beam configuration system of the multi-beam tool to rotate the n beams relative to the first direction so that the n beams are spaced apart along the first direction; instructing the beam configuration system to deflect the n beams to simultaneously i) follow the movement of the sample, and ii) scan one or more groups of N scan lines on a surface of the sample.

[0017] In some embodiments, a non-transitory computer readable medium having a set of instructions stored thereon is provided. The set of instructions is executable by a controller coupled to a multi-beam tool to cause the controller to perform a method, the method comprising: instructing a sample stage of the multi-beam tool to move a sample in a first direction, the multi-beam tool generating a primary beam of charged particles and dividing the primary beam into a beam array; instructing a beam configuration system of the multi-beam tool to deflect the beam array to i) scan a first set of scan lines in a field of view of the multi-beam tool, and ii) follow the movement of the sample during the scanning of the first set of scan lines, wherein the first set of scan lines are spread over a first distance in a first direction; after the first set of scan lines are scanned, instructing a sample holder to move the sample a first distance in the first direction; instructing the beam configuration system to deflect the beam array to i) scan a second set of scan lines in the field of view of the multi-beam tool, and ii) follow the movement of the sample during the scanning of the second set of scan lines; and moving the sample in the first direction while the first and second sets of scan lines are scanned.

[0018] The disclosed embodiment provides a method for scanning a sample area using N charged particle beams, wherein N is an integer greater than or equal to 2, and wherein the sample area includes a plurality of scanning sections of N continuous scanning lines. The method includes moving the position of the sample in a first direction; scanning a first scanning line of at least a portion of the scanning sections moving toward a detection spot of the first charged particle beam in the plurality of scanning sections using a first charged particle beam in the N charged particle beams; and scanning a second scanning line of at least a portion of the scanning sections moving toward a detection spot of the second charged particle beam in the plurality of scanning sections using a second charged particle beam in the N charged particle beams.

[0019] The disclosed embodiments provide a non-transitory computer-readable medium storing an instruction set, which can be executed by one or more processors of a charged particle beam system to cause the charged particle beam system to perform a method together with a charged particle beam source for delivering N charged particle beams to a surface of a sample in a time series. The method includes moving the position of the sample in a first direction; scanning a first scanning line of at least a portion of the scanning section moving toward a detection spot of the first charged particle beam in a plurality of scanning sections using a first charged particle beam in the N charged particle beams; and scanning a second scanning line of at least a portion of the scanning section moving toward a detection spot of the second charged particle beam in a plurality of scanning sections using a second charged particle beam in the N charged particle beams.

[0020] The disclosed embodiments also provide a method for scanning a sample by a multi-beam inspection system utilizing N×M charged particle beams, where N is an integer greater than or equal to 2. The method includes positioning N charged particle beams so that each of the N charged particle beams can scan a different scan line in a first group of N adjacent scan lines; scanning the first group of N adjacent scan lines of the sample by using the N charged particle beams when the sample moves in a first direction at a first speed; repositioning the N charged particle beams relative to the start of scanning of the first group of N adjacent scan lines so that each of the N charged particle beams can scan a different scan line in a second group of adjacent scan lines; and scanning a second group of N adjacent scan lines of the sample by using the N charged particle beams when the sample moves in the first direction at a first speed.

[0021] The disclosed embodiments also provide a method for scanning a sample placed on a stage by a multi-beam inspection system utilizing an N×M array of charged particle beams, where N and M are both integers greater than or equal to 2. The method includes positioning the N×M array of charged particle beams so that each beam at a first set of positions in the N×M array of charged particle beams can scan a different scanning segment in a first set of N×M scanning segments of the sample. The method also includes scanning a scanning line of at least a portion of the scanning segments in the first set of N×M scanning segments of the sample by using the N×M array of charged particle beams when the stage moves in a first direction at a first speed. The method also includes repositioning the N×M array of charged particle beams relative to the start of scanning of the first set of N×M scanning segments so that each beam at a second set of positions in the N×M array of charged particle beams can scan a different scanning segment in a second set of N×M scanning segments of the sample. The method further includes scanning scan lines of at least a portion of a second set of N×M scan sections of the sample by using an N×M charged particle beam array while the stage moves in a first direction at a first speed.

[0022] Other advantages of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings in which certain embodiments of the invention are set forth by way of illustration and example. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other aspects of the present disclosure will become more apparent through the description of exemplary embodiments with reference to the accompanying drawings.

[0024] Figure 1 is a schematic diagram illustrating an exemplary charged particle beam inspection system according to an embodiment of the present disclosure.

[0025] Figure 2 is a schematic diagram illustrating an exemplary electron beam tool according to an embodiment of the present disclosure.

[0026] Figure 3A and3B Examining a sample using multiple charged particle beams is schematically illustrated.

[0027] Figure 3C and 3D Schematically shows Figure 3A and 3B Movement of one of the detection spots in relative to the sample within one of the time periods T1, T2 and T3.

[0028] Figure 4A and 4B Examining a sample using multiple charged particle beams according to an embodiment of the present disclosure is schematically illustrated.

[0029] Figure 5A and 5B Examining a sample using multiple charged particle beams according to an embodiment of the present disclosure is schematically illustrated.

[0030] Figure 6 Examining a sample using multiple charged particle beams according to an embodiment of the present disclosure is schematically illustrated.

[0031] Figure 7 is a flow chart illustrating steps of an exemplary multi-beam scanning method according to an embodiment of the present disclosure.

[0032] Fig. 8A FIG. 1 is a diagram showing a primary beam wave winding according to an embodiment of the present disclosure. Figure 1 Schematic diagram of the distribution of multiple primary beam waves on the sample surface before and after the optical axis of the electron beam inspection system is rotated.

[0033] Figure 8B FIG. 1 is a diagram showing a primary beam wave winding according to an embodiment of the present disclosure. Figure 1 Schematic diagram of scanning patterns of multiple primary beam waves on a sample surface before and after the optical axis of an electron beam inspection system is shown.

[0034] Fig. 9 The embodiment of the present disclosure is used to select Fig. 8A and 8B Schematic diagram of the process of the rotation angle of the primary beam shown.

[0035] Fig.10 is a flowchart of a multi-beam scanning method according to an embodiment of the present disclosure.

[0036] Fig.11 is a schematic diagram illustrating a multi-beam interlaced scanning pattern according to an embodiment of the present disclosure.

[0037] Fig.12 is a schematic diagram showing movement trajectories of a plurality of detection spots relative to a sample during interlaced scanning according to an embodiment of the present disclosure.

[0038] Fig.13 is a schematic diagram illustrating a multi-beam interlaced scanning pattern according to an embodiment of the present disclosure.

[0039] Fig.14 is a flowchart of a multi-beam interlaced scanning method according to an embodiment of the present disclosure.

[0040] Fig.15 is a schematic diagram illustrating a multi-beam half-interlaced scanning pattern according to an embodiment of the present disclosure.

[0041] Fig.16 is a flowchart of a multi-beam half-interlaced scanning method according to an embodiment of the present disclosure.

[0042] Fig.17 is a schematic diagram showing distribution of multiple primary beam waves on the surface of a sample before and after beam repositioning according to an embodiment of the present disclosure.

[0043] Fig.18 is a schematic diagram illustrating a multi-beam scanning pattern of a “continuous scanning” mode according to an embodiment of the present disclosure.

[0044] Fig.19 is a schematic diagram showing an exemplary scanning pattern using a set of rotating primary beams according to an embodiment of the present disclosure.

[0045] Fig. 20A , 20B 20C and 20D are diagrams showing the use of an embodiment according to the present disclosure. Fig.19 A schematic diagram of an exemplary multi-beam scanning pattern of a rotating primary beam is shown. DETAILED DESCRIPTION

[0046] Reference will now be made in detail to exemplary embodiments, examples of which are shown in the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the present invention. Instead, they are merely examples of devices and methods consistent with various aspects related to the present invention as described in the appended claims.

[0047] Electronic devices are made up of circuits formed on a single piece of silicon called a substrate. Many circuits can be formed together on the same single piece of silicon and are called an integrated circuit or IC. The size of these circuits has been greatly reduced so that more circuits can fit on a substrate. For example, the IC chip in a smartphone can be as small as a fingernail but can include over 2 billion transistors, each less than 1 / 1000 the size of a human hair.

[0048] Manufacturing these extremely small ICs is a complex, time-consuming, and expensive process that typically involves hundreds of individual steps. An error in even one step can cause the finished IC to be defective, rendering it useless. Therefore, one goal of the manufacturing process is to avoid such defects in order to maximize the number of functional ICs manufactured in the process, i.e., to increase the overall yield of the process.

[0049] An integral part of improving yield is monitoring the chip manufacturing process to ensure that it is producing sufficient numbers of functional integrated circuits. One way to monitor the process is to inspect the chip's circuit structures at various stages of their formation. This inspection can be done using a scanning electron microscope (SEM). These extremely small structures can be imaged using an SEM, in effect taking a "photo" of the structure. The image can be used to determine if the structure was formed correctly, and if the structure was formed in the correct location. If the structure is defective, the process can be adjusted so that the defect is less likely to occur again.

[0050] The SEM scans the surface of a sample with a focused beam of primary electrons. The primary electrons interact with the sample and generate secondary electrons. By scanning the sample with the focused beam and capturing the secondary electrons with a detector, the SEM produces an image of the scanned area of ​​the sample.

[0051] Conventional SEMs generate images by raster scanning an electron beam over a sample held on a stage. Raster scanning is performed by repeating the following operations: moving the primary beam to scan a row of pixels across the sample; and after reaching the last pixel of the scan line, moving the primary beam back to scan the first pixel of the next row to scan the row of pixels. The extra time required / spent to move the beam from the last pixel in a row to the first pixel in the next row is called row extra consumption. Typically in conventional SEM systems, the stage remains stationary while the primary electron beam raster scans the sample area (e.g., a set of one or more scan lines) within its field of view. After the area is completely scanned, the stage jumps to move the unscanned sample area into the field of view so that the primary beam can start scanning a new area. For high-throughput inspections, some newer inspection systems use multiple electron beams. Since multiple electron beams can scan different parts of a wafer at the same time, a multi-beam electronic inspection system can inspect wafers at a higher speed than a single-beam system.

[0052] Typically, however, even these newer systems with multiple electron beams still employ the same raster scanning technique while the stage remains stationary. After the multiple beams have finished scanning the current sample area within their respective fields of view, the stage or beams may need to perform a large "jump" to an unscanned sample area. Furthermore, scanning may need to be stopped each time the stage moves, and scanning may only be resumed after the stage has fully stabilized, also adding considerable nonproductive time.

[0053] One aspect of the present disclosure relates to a system and method for arranging, configuring or controlling multiple electron beams to scan a sample simultaneously and continuously. As described in detail below, the disclosed system and method can reduce or minimize the extra line consumption associated with raster scanning or waiting time for stage movement. In addition, the disclosed system and method can optimize the movement of multiple electron beams into simple repetitive up and down movements without large "jump" movements to unscanned areas, thereby improving the overall inspection output and reducing the complexity of the control mechanism of the multi-beam tool.

[0054] For clarity, the relative sizes of components in the accompanying drawings may be exaggerated. In the following description of the accompanying drawings, the same or similar reference numerals refer to the same or similar components or entities, and only the differences with respect to the various embodiments are described. As used herein, unless otherwise explicitly stated, the term "or" covers all possible combinations unless not feasible. For example, if it is stated that a component can include A or B, then unless otherwise explicitly stated or not feasible, the component can include A or B or A and B. As a second example, if it is stated that a component can include A, B or C, then unless otherwise explicitly stated or not feasible, the component can include A or B or C or A and B or A and C or B and C or A and B and C.

[0055] Reference now Figure 1 , Figure 1 is a schematic diagram illustrating an exemplary charged particle beam inspection system 100 according to an embodiment of the present disclosure. Figure 1 As shown, the charged particle beam inspection system 100 includes a main chamber 10, a load lock chamber 20, an electron beam tool 40, and an equipment front end module (EFEM) 30. The electron beam tool 40 is located in the main chamber 10. Although the description and drawings are directed to electron beams, it should be understood that the embodiments are not intended to limit the present disclosure to specific charged particles.

[0056] The EFEM 30 includes a first load port 30a and a second load port 30b. The EFEM 30 may include additional load ports. The first load port 30a and the second load port 30b may, for example, accommodate a front opening pod (FOUP) containing wafers (e.g., semiconductor wafers or wafers made of other materials) or samples to be inspected (wafers and samples are collectively referred to as "wafers" hereinafter). One or more robotic arms (not shown) in the EFEM 30 transport the wafers to the load lock chamber 20.

[0057] The load lock chamber 20 may be connected to a load lock vacuum pump system (not shown) that removes gas molecules in the load lock chamber 20 to reach a first pressure below atmospheric pressure. After reaching the first pressure, one or more robots (not shown) transport the wafer from the load lock chamber 20 to the main chamber 10. The main chamber 10 is connected to a main chamber vacuum pump system (not shown) that removes gas molecules in the main chamber 10 to reach a second pressure below the first pressure. After reaching the second pressure, the wafer is inspected by an electron beam tool 40. In some embodiments, the electron beam tool 40 may include a single beam electron inspection tool. In other embodiments, the electron beam tool 40 may include a multi-beam electron inspection tool.

[0058] The controller 50 is electrically connected to the electron beam tool 40. The controller 50 may be a computer configured to perform various controls of the charged particle beam inspection system 100. The controller 50 may also include processing circuits configured to perform various signal and image processing functions. Figure 1 30, but it should be understood that the controller 50 can be part of the structure. Although the present disclosure provides an example of a main chamber 10 that houses an electron beam inspection tool, it should be noted that the aspects of the present disclosure in its broadest sense are not limited to chambers that house electron beam inspection tools. Instead, it should be understood that the aforementioned principles can also be applied to other tools that operate at a second pressure.

[0059] Reference now Figure 2 , Figure 2 is a schematic diagram showing an exemplary electron beam tool 40 according to an embodiment of the present disclosure, the electron beam tool 40 includes a Figure 1 A multi-electron beam inspection tool that is part of an exemplary charged particle beam inspection system 100. The multi-electron beam tool 40 (also referred to herein as device 40) includes an electron source 201, a gun hole plate 271, a focusing lens 210, a source conversion unit 220, a primary projection optical system 230, a motorized stage 209, and a sample holder 207, the sample holder 207 being supported by the motorized stage 209 to hold a sample 208 to be inspected (e.g., a wafer or a photomask). The multi-electron beam tool 40 may also include a secondary projection system 250 and an electronic detection device 240. The primary projection optical system 230 may include an objective lens 231. The electronic detection device 240 may include a plurality of detection elements 241, 242, and 243. The beam splitter 233 and the deflection scanning unit 232 may be located inside the primary projection optical system 230.

[0060] The electron source 201, the aperture plate 271, the condenser lens 210, the source conversion unit 220, the beam splitter 233, the deflection scanning unit 232 and the primary projection optical system 230 can be aligned with the primary optical axis 204 of the device 40. The secondary projection system 250 and the electron detection device 240 can be aligned with the secondary optical axis 251 of the device 40.

[0061] The electron source 201 may include a cathode (not shown) and an extractor or an anode (not shown), wherein during operation, the electron source 201 is configured to emit primary electrons from the cathode, and the primary electrons are extracted or accelerated by the extractor and / or the anode to form a primary electron beam 202, which forms a primary beam overlap (virtual or real) 203. The primary electron beam 202 can be visualized as being emitted from the primary beam overlap 203.

[0062] The source conversion unit 220 may include an image forming element array (not shown), a field curvature compensator array (not shown), an astigmatism compensator array (not shown), and a beam limiting aperture array (not shown). The image forming element array may include a plurality of micro deflectors or micro lenses to affect a plurality of primary beam waves 211, 212, 213 of the primary electron beam 202, and form a plurality of parallel images (virtual or real) of the primary beam overlap 203, one parallel image for each of the primary beam waves 211, 212, and 213. The field curvature compensator array may include a plurality of micro lenses to compensate for the field curvature aberration of the primary beamlets 211, 212, and 213. The astigmatism compensator array may include a plurality of micro diffusers to compensate for the astigmatism aberration of the primary beam waves 211, 212, and 213. The beam limiting aperture array may be configured to limit the diameter of a single primary beam wave 211, 212, and 213. Figure 2 As an example, three primary beams 211, 212, and 213 are shown, and it should be understood that the source conversion unit 120 can be configured to form any number of primary beams. The controller 50 can be connected to Figure 1 The controller 50 may be used to control various parts of the charged particle beam inspection system 100, such as the electronic detection device 240, the primary projection optical system 230, or the motorized stage 209. In some embodiments, as described in further detail below, the controller 50 may perform various image and signal processing functions. The controller 50 may also generate various control signals to control the operation of the charged particle beam inspection system 100.

[0063] The condenser lens 210 is configured to focus the primary electron beam 202. The condenser lens 210 can also be configured to adjust the current of the primary beam waves 211, 212 and 213 downstream of the source conversion unit 220 by changing the focal length of the condenser lens 210. Alternatively, the current can be changed by changing the radial size of the beam limiting aperture within the beam limiting aperture array corresponding to a single primary beam wave. The current can be changed by changing the radial size of the beam limiting aperture and the focal length of the condenser lens 210. The condenser lens 210 can be a movable condenser lens, which can be configured so that the position of its first principal plane is movable. The movable condenser lens can be configured to be magnetic, which can cause the off-axis beam waves 212 and 213 to be incident on the beamlet limiting mechanism at a rotation angle. The rotation angle varies with the focal length of the movable condenser lens and the position of the first principal plane. In some embodiments, the movable condenser lens can be a movable anti-rotation condenser lens, which includes an anti-rotation lens having a movable first principal plane.

[0064] The objective lens 231 can be configured to focus the beams 211, 212, and 213 onto the sample 208 for inspection, and in the current embodiment, three detection spots 221, 222, and 223 can be formed on the surface of the sample 208. The aperture plate 271 is configured to block peripheral electrons of the primary electron beam 202 in operation to reduce the Coulomb effect. The Coulomb effect may increase the size of each detection spot 221, 222, and 223 of the primary beams 211, 212, and 213 and thus reduce the inspection resolution.

[0065] The beam splitter 233 may be, for example, a Wien filter including an electrostatic deflector ( Figure 2 ). In operation, the beam splitter 233 can be configured to exert an electrostatic force on each electron of the primary beams 211, 212, and 213 through an electrostatic dipole field. The electrostatic force is equal in magnitude but opposite in direction to the magnetic force exerted on each electron by the magnetic dipole field of the beam splitter 233. The primary beams 211, 212, and 213 can therefore pass at least substantially straight through the beam splitter 233 with a deflection angle that is at least substantially zero.

[0066] The deflection scanning unit 232 is configured in operation to deflect the primary beams 211, 212, and 213 to scan detection spots 221, 222, and 223 on a single scanning area in a portion of the surface of the sample 208. In response to the incidence of the primary beams 211, 212, and 213 at the detection spots 221, 222, and 223, electrons come out of the sample 208 and generate three secondary electron beams 261, 262, and 263. Each secondary electron beam 261, 262, and 263 typically includes electrons with different energies, including secondary electrons (electron energy ≤ 50 eV) and backscattered electrons (electron energy is between 50 eV and the landing energy of the primary beams 211, 212, and 213). The beam splitter 233 is configured to deflect the secondary electron beams 261, 262, and 263 toward the secondary projection system 250. The secondary projection system 250 then focuses the secondary electron beams 261, 262, and 263 onto the detection elements 241, 242, and 243 of the electron detection device 240. The detection elements 241, 242, and 243 are arranged to detect correspondingly to the secondary electron beams 261, 262, and 263 and generate corresponding signals, which are sent to, for example, the controller 50 or a signal processing system (not shown), for example, to construct an image of the corresponding scan area of ​​the sample 208.

[0067] In some embodiments, the detection elements 241, 242, and 243 detect correspondingly with the secondary electron beams 261, 262, and 263, respectively, and generate corresponding intensity signal outputs (not shown) to the image processing system (e.g., the controller 50). In some embodiments, each detection element 241, 242, and 243 may include one or more pixels. The intensity signal output of the detection element may be the sum of the signals generated by all pixels within the detection element.

[0068] In some embodiments, the controller 50 may include an image processing system, which includes an image acquisition device (not shown), a storage device (not shown). The image acquisition device may include one or more processors. For example, the image acquisition device may include a computer, a server, a mainframe, a terminal, a personal computer, any kind of mobile computing device, or a combination thereof. The image acquisition device may be coupled to the electronic detection device 240 of the device 40 through a medium such as an electrical conductor, a fiber optic cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, a wireless broadcast, or a combination thereof. In some embodiments, the image acquisition device may receive a signal from the electronic detection device 240 and may construct an image. The image acquisition device may thus acquire an image of the sample 208. The image acquisition device may also perform various post-processing functions, such as generating contours, superimposing indicators on the acquired image, and the like. The image acquisition device may be configured to perform adjustments to the brightness and contrast of the acquired image, etc. In some embodiments, the storage device may be a storage medium such as a hard disk, a flash drive, a cloud storage device, a random access memory (RAM), other types of computer-readable memory, and the like. The memory may be coupled to the image acquisition device and may be used to save the scanned raw image data as a raw image and a post-processed image.

[0069] In some embodiments, the image acquirer can acquire one or more images of the sample based on the imaging signal received from the electronic detection device 240. The imaging signal can correspond to a scanning operation for performing charged particle imaging. The acquired image can be a single image including multiple imaging areas. The single image can be stored in a storage device. The single image can be an original image, which can be divided into multiple areas. Each area can include an imaging area containing features of the sample 208. The acquired image can include multiple images of a single imaging area of ​​the sample 208 sampled multiple times in a time series. Multiple images can be stored in a storage device. In some embodiments, the controller 50 can be configured to perform an image processing step on multiple images of the same position of the sample 208.

[0070] In some embodiments, the controller 50 may include a measurement circuit (e.g., an analog-to-digital converter) to obtain the distribution of the detected secondary electrons. The electron distribution data collected during the detection time window is combined with the corresponding scan path data of the primary electron beam 202 incident on the wafer surface to reconstruct an image of the inspected wafer structure. The reconstructed image can be used to reveal various features of the internal or external structure of the sample 208, which can be used to reveal any defects that may exist in the wafer.

[0071] In some embodiments, the controller 50 may control the motorized stage 209 to move the sample 208 during the inspection of the sample 208. In some embodiments, the controller 50 may enable the motorized stage 209 to continuously move the sample 208 at a constant speed in one direction. In other embodiments, the controller 50 may enable the motorized stage 209 to change the movement speed of the sample 208 over time according to the steps of the scanning process.

[0072] although Figure 2 The apparatus 40 is shown to use three primary electron beam waves, but it should be understood that the apparatus 40 may generate or use two or more primary electron beam waves. The present disclosure does not limit the number of primary electron beam waves used in the apparatus 40.

[0073] Reference now Figure 3A and 3B , Figure 3A and 3B Schematic diagram of the use of multiple charged particle beams to examine a sample. Figure 3A and 3B In the embodiment shown, four primary beams are directed at a sample (such as Figure 2 Four detection spots 310A-310D are generated on the sample 208). Figure 3A The movement of four detection spots 310A-310D relative to the sample is shown. Figure 3B Four detection spots 310A-310D and the movement of the sample relative to the absolute reference system are shown. The four detection spots 310A-310D can be but need not be arranged in a row. In the embodiment shown, the diameter of the four detection spots is W. However, in the disclosed embodiment, the diameters of the detection spots do not have to be the same. The shape of the area 300 to be inspected is rectangular, but not necessarily rectangular. For ease of explanation, two directions x and y are defined in the absolute reference system. The x and y directions are perpendicular to each other.

[0074] In some embodiments, the movement of the detection spot can be coordinated with the movement of the sample. Figure 3A As shown, in the time period T1, the four detection spots 310A-310D move a length L in the x direction relative to the sample, but do not move in the y direction. Correspondingly, in the same time period T1, the sample moves a length K in the y direction relative to the absolute reference system, but does not move in the x direction relative to the absolute reference system; and the four detection spots 310A-310D move a length K in the y direction relative to the absolute reference system, and move a length L in the x direction relative to the absolute reference system, as shown in FIG. Figure 3B Thus, during the time period T1, the four detection spots 310A-310D move in the y direction at the same speed as the sample.

[0075] The moving directions of the detection spots 310A-310D in the time period T1 do not have to be the same. The moving lengths of the detection spots 310A-310D in the time period T1 do not have to be the same. The detection spots 310A-310D may or may not move relative to each other.

[0076] exist Figure 3A and 3B In the illustrated embodiment, in the time period T1, four sub-areas 301A, 302A, 303A and 304A are checked by four detection spots 310A, 310B, 310C and 310D respectively. At the end of the time period T1, the four detection spots 310A-310D move the length L in the -x direction relative to the absolute reference system, and move the width W (that is, the width of one of the four detection spots 310A-310D) in the -y direction relative to the absolute reference system. Therefore, relative to the sample, the four detection spots 310A-310D move to the -x end of the sub-areas 301B, 302B, 303B and 304B that can be adjacent to the sub-areas 301A, 302A, 303A and 304A respectively. In this way, after reaching the last pixel of the scan line, each detection spot will traverse back to the starting point of the next scan line. Adjacent scan lines can be separated by a distance corresponding to the pixel size of the image generated by the electron beam tool. The extra time required for flying back is called line extra consumption. In some cases, this flyback may be fast enough to make the additional consumption of line negligible.In addition, the additional consumption of line may be included in the time period T1.

[0077] In time periods T2 and T3, the four detection spots 310A-310D and the sample move in the same manner as in time period T1. Thus, during T2, four sub-areas 301B, 302B, 303B, and 304B are inspected, and in T3, four sub-areas 301C, 302C, 303C, and 304C are inspected by the four detection spots 310A-310D.

[0078] At the end of time period T2, four detection spots 310A-310D move to the -x ends of sub-regions 301C, 302C, 303C and 304C respectively in the same manner as at the end of time period T1. Sub-regions 301C, 302C, 303C and 304C may be adjacent to sub-regions 301B, 302B, 303B and 304B respectively.

[0079] exist Figure 3A and 3BIn the illustrated embodiment, the pitch S of the four detection spots 310A-310D in the y direction is equal to 3W. Therefore, at the end of the time period T3, the combination of the inspected sub-areas 301C, 301B, 301A, 302C, 302B, 302A, ..., and 304A has no gap in the y direction. At the end of the time period T3, the four detection spots 310A-310D can move a length L in the -x direction relative to the absolute reference system, and can move 10W in the -y direction relative to the absolute reference system. For example, at the end of the time period T3, the detection spot 310D needs to move from the +x end of the sub-area 304C to the -x end of the sub-area 304D. In fact, relative to the absolute reference system, the detection spot 310D moves a length L in the -x direction and moves 10W in the -y direction. The movement of 10W in the -y direction can be achieved by deflecting the four primary beams in the -y direction. Alternatively or additionally, this movement can be achieved by allowing the sample to move in the y direction. Thus, relative to the sample, the four detection spots 310A-310D are moved to the -x ends of the sub-regions 301D, 302D, 303D, and 304D, respectively, where the sub-region 304D may be adjacent to the sub-region 301C. After this movement, the four detection spots 310A-310D are located at the same position relative to the absolute reference system, as at the beginning of the time period T1. During additional time periods (e.g., time period T4), the four detection spots 310A-310D may inspect additional sub-regions (e.g., 301D, 302D, 303D, 304D, etc.).

[0080] During the time period T1-T3, the sample moves 3K in the y direction relative to the absolute reference system (see Figure 3B ); the four detection spots 310A-310D move zero in the y direction relative to the absolute reference system; the four detection spots 310A-310D move 12W in the -y direction relative to the sample. Therefore, 3K equals 12W, that is, K equals 4W. The speed of the sample in the time period T1-T3 can be kept constant.

[0081] In summary, when the number of detection spots is M, and the pitch of the detection spots in the x-direction is S=NW, where N is an integer equal to or greater than 2, the number of time periods required to combine the inspected sub-areas to have no gaps in the x-direction is N, and the distance K traveled by the sample in each time period is equal to MW. Figure 3A and 3B In the example of , N=3, M=4 and K=4W.

[0082] Figure 3CThe movement of one of the detection spots 310A-310D relative to the sample during one of the time periods T1, T2 and T3 is schematically shown. Relative to the sample, the detection spot moves only a distance L in the x-direction during this time period, but not in the y-direction. Figure 3D The movement of the detection spot relative to the absolute reference system during this time period is schematically shown. Relative to the absolute reference system, during this time period, the detection spot moves a distance L in the x direction and a distance K in the y direction. Relative to the absolute reference system, the angle θ between the movement direction of the detection spot and the movement direction of the sample is arctan (L / K).

[0083] The above embodiment requires that at the end of time period T3, the detection spots 310A-310D perform a 10W "jump" in the -y direction relative to the absolute reference frame. However, in some embodiments, such a jump is not performed at the end of time period T3. Instead, the four detection spots 310A-310D are continuously moved to the end of the next adjacent sub-area in the same manner as at the end of time periods T1 and T2. Specifically, the reference frame Figure 3A At the end of time period T3, detection spot 310D moves to the -x end of sub-region 303A previously scanned by detection spot 310C; detection spot 310C moves to the -x end of sub-region 302A previously scanned by detection spot 310B; detection spot 310B moves to the -x end of sub-region 301A previously scanned by detection spot 310A; detection spot 310A moves to the -x end of sub-region 304D adjacent to sub-region 301C. In this way, each of the four detection spots 310A-310D will respectively inspect the same sub-region. That is, some sub-regions can be scanned four times by one beam wave. Therefore, the generated signal can be used to perform frame averaging to improve the signal-to-noise ratio of the constructed sample image.

[0084] Reference now Figure 4A and 4B , Figure 4A and 4B Schematically illustrates the use of multiple charged particle beams to inspect a sample according to an exemplary embodiment of the present disclosure. Figure 4A and 4B In the embodiment shown, three primary beams may be applied to a sample such as Figure 2 Three detection spots 451, 452 and 453 are generated on the sample 208). Figure 4A The movement of three detection spots 451 , 452 , 453 relative to the sample is shown. Figure 4BThe movement of three detection spots 451, 452, 453 and the sample relative to the absolute reference system is shown. The three detection spots 451, 452, 453 can be but not necessarily arranged in a row. For ease of explanation, two directions x and y are defined in the absolute reference system. The x and y directions are perpendicular to each other.

[0085] In some embodiments, the shape of the scan area 460 of the sample to be inspected is rectangular, but it does not have to be rectangular. The scan area 460 of the sample can be divided into a plurality of scan lines 400, 401, 402, ..., 434 and 435. The width of the scan line can match or be roughly similar to the width of the detection spot. In such an embodiment, the scan line can be scanned and inspected by the detection spot. Although Figure 4A Thirty-six scan lines (scan lines 400-435) are shown, but it should be understood that the scan area 460 may include any number of scan lines, depending on the size of the scan area 460 and the width of the detection spot.

[0086] In some embodiments, every three consecutive scan lines can be grouped together and form a scan segment. For example, the first three scan lines 400, 401, 402 can form a scan segment 471; the next three scan lines 403, 404, 405 can form a scan segment 472; the next three scan lines 406, 407, 408 can form a scan segment 473, and so on. In some embodiments, the three detection spots 451, 452, 453 can be arranged so that each detection spot can only scan the corresponding scan line of the scan segment. For example, as Figure 4A As shown, the detection spot 451 can be configured to scan the first scan line (the far right) in the scan segment; the detection spot 452 can be configured to scan the second scan line (the middle) in the scan segment; and the detection spot 453 can be configured to scan the third scan line (the far left) in the scan segment. Accordingly, in such an embodiment, the detection spot 451 can scan 400, 403, 406, ..., 415, etc. during time periods T1, T2, T3, ..., T6, respectively; the detection spot 452 can scan 404, 407, 410, ..., 423, etc. during time periods T1, T2, T3, ..., T6, respectively; and the detection spot 453 can scan 408, 411, 414, ..., 423, etc. during time periods T1, T2, T3, ..., T6, respectively. Although Figure 4A and 4B Movement of the detection spot and sample is shown during the first six time periods (T1-T6), but it will be appreciated that the sequence may continue until the sample is completely scanned and inspected.

[0087] In some embodiments, during each time period, when the detection spots 451, 452, and 453 scan the scan line, the sample can move a length K in the y direction relative to the absolute reference system. In such an embodiment, the sample may not move in the x direction relative to the absolute reference system. Accordingly, during each time period, the detection spots 451, 452, and 453 can move in the x direction to scan the scan line, while also moving in the y direction at the same speed as the sample (e.g., speed K), thereby following the movement of the sample when scanning the scan line. And, after the scan is completed, the detection spots 451, 452, and 453 can be retraceable in the -x direction and -y direction to the starting point of the next set of scan lines. In other embodiments, during each time period, the detection spots 451, 452, and 453 can only move in the x direction relative to the absolute reference system, and not move in the y direction. Therefore, in such an embodiment, the scan line can be tilted relative to the sample away from the sample movement direction (i.e., not perpendicular to the y direction) to accommodate sample movement.

[0088] For example, Figure 4B As shown, the sample can move 3W (i.e., the width of the scan segment) in each time period (i.e., each time period K=3W), thereby providing a new scan segment to the detection spot in each time period. In such an embodiment, in the first half of the time period T1, the detection spots 451, 452, 453 can move in the x direction to scan the scan lines 400, 404, 408 respectively, while also moving 1.5W in the y direction. After the scan is completed, in the second half of the time period T1, the detection spots 451, 452, and 453 can move back in the -x direction, while also moving 1.5W in the -y direction to the starting point of the next group of scan lines (e.g., 403, 407, and 411). In this way, after reaching the last pixel of the scan line, each detection spot will traverse back to the starting point of the next scan line. In subsequent time periods (e.g., T2, T3, ...), the detection spots 451, 452, 453 and the sample can be repeatedly moved in the same manner as during the time period T1. Thus, scan lines 403, 407, and 411 may be scanned during time period T2; scan lines 406, 410, 414 may be scanned during time period T3, and so on.

[0089] Compared with Figure 3A and 3B In contrast to the embodiment described above, in which the detection spot needs to "jump" in the -y direction at the end of time period T3, Figure 4A and 4B In the illustrated embodiment, there is no need to perform such "jumping" because each detection spot scans only a corresponding set of scan lines of the scan segment. Instead of performing "jumping", detection spots 451, 452 and 453 can continuously repeat the above movement to scan scan lines as the sample moves.

[0090] In general, the speed K of sample movement can be determined as follows:

[0091] K = MW / time period, equation (1)

[0092] Where M is the number of detection spots and W is the width of the detection spots. In addition, the pitch S of the detection spots can be determined as follows:

[0093] S = (nM + 1) × W, equation (2)

[0094] Where n is an integer equal to or greater than 2. Figure 4A and 4B In the example of , the number of detection spots is 3 (ie, M=3) and n=1, resulting in K=3W and S=4W per time period. Figure 4A and 4B An exemplary embodiment using three detection spots (ie, M=3) is shown, but it will be appreciated that any number of detection spots may be used to scan the sample.

[0095] In some embodiments, some scan lines in the first two scan segments (e.g., scan segments 471 and 472) may not be scanned by the above scan sequence. Therefore, in some embodiments, scan area 460 may need to include a buffer area 490 that is not required to be checked. In such an embodiment, except for the scan lines in buffer area 490, all scan lines (e.g., scan lines 406, 407, 408, 409, etc.) can be scanned continuously without any gaps. Although in Figure 4A and 4B Only one buffer region (e.g., buffer region 490) is shown in FIG. 4 , but it is understood that scanning region 460 may include more than one buffer region. For example, another buffer region (not shown) may be included at the end of scanning region 460 (e.g., the leftmost scanning segment).

[0096] Reference now Figure 5A and 5B , Figure 5A and 5B Examining a sample using multiple charged particle beams according to an exemplary embodiment of the present disclosure is schematically illustrated. Figure 5A and 5B Shows that with Figure 4A and 4B Example of the same scanning configuration, except in Figure 5A and 5B In the illustrated embodiment, the pitch S of the detection spots (e.g., Figure 5A The distance between the detection spot 551 and the detection spot 552 in the image is larger.

[0097] Similar to Figure 4A , the scanning area 560 of the sample can be divided into a plurality of scan lines 500, 501, 502, ..., 534 and 535. The width of the scan line can match or be roughly similar to the width of the detection spot. In such an embodiment, the scan line can be scanned and inspected by the detection spot. Although Figure 5A Thirty-six scan lines (scan lines 500-535) are shown, but it should be understood that the scan area 560 may include any number of scan lines, depending on the size of the scan area 560 and the width of the detection spot.

[0098] In some embodiments, every three consecutive scan lines can be grouped together and form a scan segment. For example, the first three scan lines 500, 501, 502 can form a scan segment 571; the next three scan lines 503, 504, 505 can form a scan segment 572; and so on. In some embodiments, the three detection spots 551, 552, 553 can be arranged so that each detection spot can only scan the corresponding scan line of the scan segment. For example, Figure 5A As shown, the detection spot 551 can be configured to scan the first scan line (the far right) in the scan segment; the detection spot 552 can be configured to scan the second scan line (the middle) in the scan segment; and the detection spot 553 can be configured to scan the third scan line (the far left) in the scan segment. Therefore, in such an embodiment, the detection spot 551 can scan 500, 503, 506, ..., 521, etc. during time periods T1, T2, T3, ..., T8, respectively; the detection spot 552 can scan 507, 510, 513, ..., 528, etc. during time periods T1, T2, T3, ..., T8, respectively; the detection spot 553 can scan 514, 517, 520, ..., 535, etc. during time periods T1, T2, T3, ..., T8, respectively. Although Figure 5A and 5B Movement of the detection spot and sample is shown during the first eight time periods (T1-T8), but it will be appreciated that this sequence may continue until the sample is completely scanned and inspected.

[0099] Similar to Figure 4A and 4BIn the illustrated embodiment, during each time period, when the detection spots 551, 552, and 553 scan the scan line, the sample can move a length K in the y direction relative to the absolute reference system. In such an embodiment, the sample may not move in the x direction relative to the absolute reference system. Accordingly, during each time period, the detection spots 551, 552, and 553 can move in the x direction to scan the scan line, while also moving in the y direction at the same speed as the sample (e.g., speed K), thereby following the movement of the sample when scanning the scan line. And, after the scan is completed, the detection spots 551, 552, and 553 can retrace in the -x direction and the -y direction to the starting point of the next set of scan lines.

[0100] For example, Figure 5B As shown, the sample can move 3W (i.e., the width of the scanning section) in each time period (i.e., each time period K=3W), thereby providing a new scanning section for the detection spot in each time period. In such an embodiment, in the first half of the time period T1, the three detection spots 551, 552, and 553 can move in the x direction to scan the scanning lines 500, 507, and 514 respectively, and also move 1.5W in the y direction. After the scanning is completed, in the second half of the time period T1, the detection spots 551, 552, and 553 can move backward in the -x direction, and can also move 1.5W in the -y direction to the starting point of the next group of scanning lines (e.g., 503, 510, and 517). In this way, after reaching the last pixel of the scanning line, each detection spot will traverse back to the starting point of the next scanning line. In subsequent time periods (e.g., T2, T3, ...), the detection spots 551, 552, 553 and the sample can be repeatedly moved in the same manner as in the time period T1. Thus, scan lines 503, 510, and 517 may be scanned during time period T2; scan lines 506, 513, 520 may be scanned during time period T3, and so on.

[0101] Similar to Figure 4A and 4B The described embodiments, in Figure 5A and 5B In the illustrated embodiment, no "jumping" needs to be performed, since each detection spot scans only a corresponding set of scan lines of the scan segment. Instead of performing "jumping", the detection spots 551, 552 and 553 can continuously repeat the above movement to scan the scan lines as the sample moves.

[0102] As about Figure 4A and 4B The speed K of the sample movement can be determined as follows:

[0103] K = MW / time period, Equation (3)

[0104] Where M is the number of detection spots and W is the width of the detection spots. In addition, the pitch S of the detection spots can be determined as follows:

[0105] S = (nM + 1) × W, Equation (4)

[0106] Wherein n is an integer equal to or greater than 2.

[0107] Figure 5A and 5B An embodiment is shown in which the number of detection spots is 3 (ie, M = 3) and n = 2. Therefore, the speed K is equal to 3W and the pitch S is equal to 7W in each time period.

[0108] In some embodiments, some of the scan lines in the first four scan segments (e.g., scan segments 571, 572, 573, and 574) may not be scanned by the above-described scan sequence. Therefore, in some embodiments, the scan area 560 may need to include a buffer area 590 that does not need to be checked. In such an embodiment, except for the scan lines in the buffer area 590, all scan lines (e.g., scan lines 512, 513, 514, 515, etc.) may be scanned continuously without any gaps. Although in Figure 5A and 5B Only one buffer region (e.g., buffer region 590) is shown in FIG. 5 , but it is understood that scanning region 560 may include more than one buffer region. For example, another buffer region (not shown) may be included at the end of scanning region 560 (e.g., the leftmost scanning segment).

[0109] Reference now Figure 6 , Figure 6 Schematically illustrates the use of multiple charged particle beams to inspect a sample according to an exemplary embodiment of the present disclosure. Figure 4A , 4B , 5A and 5B show three detection spots (e.g., Figure 4A and 4B The detection spots 451, 452, 453 and Figure 5A and 5B The detection spots 551, 552, 553 in the sample are located along the sample (such as Figure 2 The detection spots and thus the primary beams may be aligned in a row in the direction of movement of the sample 208), but the detection spots and thus the primary beams may have other spatial arrangements. In some embodiments, multiple primary beams may be arranged in a matrix. For example, Figure 6As shown, nine detection spots 601, 602, ..., 609 can be arranged in a 3×3 matrix configuration. In such an embodiment, the first row of detection spots (601, 602, 603) can scan the first scanning area 660A. Similarly, the second row (604, 605, 606) and the third row (607, 608, 609) can scan the second scanning area 660B and the third scanning area 660C, respectively. Although Figure 6 It is shown that adjacent rows of detection spots scan adjacent scanning areas, but it is understood that adjacent rows of detection spots can scan non-adjacent scanning areas. For example, the first row of detection spots (601, 602, 603) can scan the first scanning area 660A, and the second row of detection spots (604, 605, 606) can scan the third scanning area 660C.

[0110] Similar to the above embodiment, the sample including scanning areas 660A, 660B, and 660C can be constantly moved in the y direction at a speed K relative to the absolute reference frame, while the scan lines in scanning areas 660A, 660B, and 660C are simultaneously scanned by three rows of detection spots. In such an embodiment, each scanning area (e.g., 660A, 660B, or 660C) can be moved at a speed K relative to the absolute reference frame. Figure 4A and 4B The same manner as described is scanned.

[0111] As compared to Figure 4A and 4B As described above, some scan lines in the first two scan sections (e.g., scan sections 671 and 672) may not be scanned by the above scan sequence. Therefore, in some embodiments, scan areas 660A, 660B, and 660C may need to include a buffer area 690 that does not need to be checked. In such an embodiment, except for the scan lines in the buffer area 690, all scan lines (e.g., scan lines in scan sections 673, 674, 675, etc.) can be scanned continuously without any gaps. Although in Figure 6 Only one buffer region (e.g., buffer region 690) is shown in the figure, but it is understood that scanning regions 660A, 660B, and 660C may include more than one buffer region. For example, another buffer region (not shown) may be included at the end (e.g., the leftmost scanning segment) of scanning regions 660A, 660B, and 660C.

[0112] although Figure 6 A configuration of a primary beam with 9 detection spots 601-609 arranged in a 3×3 matrix is ​​shown, but it should be understood that the principles disclosed herein can be applied to any number and configuration of primary beams, such as primary beams arranged in a 3×2, 4×4, 5×5, 3×5, 8×5, 20×20 or any size matrix configuration.

[0113] Reference now Figure 7 , Figure 7 is a flow chart showing the steps of an exemplary multi-beam scanning method according to an embodiment of the present disclosure. The method can be performed by a multi-electron beam tool (such as Figure 1 The electron beam tool 40 is performed.

[0114] In step 710, a multi-electron beam tool delivers N charged particle beams to a sample under inspection (such as Figure 2 The surface of a region of the sample 208 in the sample, wherein N charged particle beams generate N detection spots (such as Figure 4A In some embodiments, the scanning area of ​​the sample can be divided into a plurality of scanning lines (such as Figure 4A 400, 401, 402, ..., 435), and every N consecutive scan lines can be grouped together and form a scan segment. Figure 4A As shown, in the case of using three detection spots, the first three scan lines 400, 401, 402 may form a scan segment 471; the next three scan lines 403, 404, 405 may form a scan segment 472; and so on.

[0115] In step 720, the multi-electron beam tool controls a motorized sample stage (such as Figure 2 The motorized stage 209 of the embodiment of the present invention moves the sample in a first direction while scanning and inspecting the sample. In some embodiments, the sample can be moved continuously at a constant speed. In other embodiments, the speed of the sample movement can vary over time according to the steps of the scanning process. It should be understood that step 720 can be before step 710, or the execution of steps 710 and 720 can be started at the same time.

[0116] In steps 730 and 740, the multi-electron beam tool deflects N charged particle beams to move N detection spots on the surface of the sample to scan the scan line. For example, in each time period, the multi-electron beam tool moves N detection spots in a second direction (such as Figure 4A and 4B The N detection spots are moved in the x direction (i.e., the moving direction of the sample, such as Figure 4A and 4B The N detection spots move at the same speed (e.g., speed K) as the sample in the y direction (e.g., speed K), thereby following the movement of the sample while scanning the scan lines. And, after the scan is completed, the N detection spots can be scanned back to the starting point of the next set of scan lines.

[0117] In some embodiments, the N detection spots are arranged so that each detection spot can scan a corresponding scan line of the scan section. Figure 4A The detection spot 451) can be configured to scan only the first scanning line of the scanning section, and the second detection spot (such as Figure 4A The Nth probe spot 452) can be configured to scan only the second scan line of the scan segment, and similarly, the Nth probe spot can be configured to scan only the Nth scan line of the scan segment. In this way, the multi-electron beam tool does not need to make large "jump" movements because each probe spot only scans a corresponding set of scan lines without much (if any) overlap. Instead of making "jumps", the N probe spots can continuously repeat the above-mentioned movement along the scan lines of the sample while the sample is moved in the first direction.

[0118] although Figure 3A and 3B Four detection spots 310A-310D are shown aligned in a row along the direction of movement of the sample, but the detection spots and thus the primary beams may have other spatial arrangements. For example, a plurality of primary beams may be arranged in a matrix, such as Fig. 8A and 8B shown. Fig. 8A FIG. 2 is a diagram showing a primary beam wave around an optical axis (eg, Figure 2 Before and after the rotation of the main optical axis 204) of the plurality of primary beams (eg, Figure 2 Schematic diagram of the distribution of primary beam waves 211, 212 and 213) on the surface of the sample. Figure 8B is a schematic diagram showing scanning patterns of a plurality of primary beams on the surface of a sample before and after rotation according to an embodiment of the present disclosure. Fig. 8A and 8B Four detection spots (or primary beams) are shown arranged in a 2×2 matrix, but it is contemplated that the principles disclosed herein may be applied to any number of primary beams, such as primary beams arranged in a 3×3, 4×5, 5×5, or 20×20 matrix.

[0119] refer to Fig. 8A and 8B The four detection spots 810A-810D may be initially arranged in a 2×2 matrix, with each column of the matrix along the moving direction of the sample (see Fig. 8A and 8B Each of the detection spots 810A-810D can be detected in a manner similar to Figures 3A-3DThe manner shown performs an xy scan on a portion of the area 800 on the sample. According to the disclosed embodiment, the four detection spots 810A-810D can be rotated relative to the sample so that each of the four detection spots 810A-810D can move on a non-overlapping scan line (see Fig. 8A and 8B The rotation can be controlled by (but not limited to) Figure 2 The deflection scanning unit 232 can be rotated to rotate the primary beam, rearrange the array of image forming elements in the electron beam tool 40, or rotate the sample. After rotation, each detection spot 810A-810D can move on a longer scan line without overlapping. Because the time to switch scan lines for the detection spots is fixed, the time overhead associated with each scan line can be reduced, and the overall output of the electron beam tool 40 can be improved.

[0120] like Figure 8B As shown on the right side of FIG, after the beam is rotated, the four detection spots 810A-810D are no longer aligned along the sample movement direction. Therefore, the actual area scanned by the four detection spots 810A-810D (the area covered by the scan line) is larger than the field of view of the electron beam tool. Specifically, Figure 8B In FIG. 8 , region 800 is the region imaged by the electron beam tool. The length of each scan line 1, 2, 3, 4, ... is greater than the width of region 800, so all scan lines can cover region 800 together.

[0121] Fig. 9 The embodiment according to the present disclosure is shown in FIG. Fig. 8A and 8B The rotation process shown is a schematic diagram of the method of selecting the rotation angle. For illustrative purposes only, Fig. 9 Nine detection spots 1, 2, 3, 4, ..., 9 are shown arranged in a matrix. Before the rotation occurs, the detection spots have a pitch S along the moving direction of the sample. After rotating the pattern of detection spots by a certain angle, the beam distance D along the moving direction has the following relationship:

[0122]

[0123] According to the disclosed embodiment, a rotation angle The detection spots can be made to have the same beam distance D along the moving direction, namely:

[0124] D 12 =D 34 Equation (7)

[0125] Equations (5)-(7) above yield:

[0126]

[0127] thereby,

[0128]

[0129] To generalize the above calculations to the detection spots (i.e., primary beam waves) arranged in an M×N matrix (i.e., a matrix with M rows and N columns, with the columns of the matrix initially aligned with the direction of movement of the sample), the beam distance D along the direction of movement should satisfy:

[0130] D 1，2 =D N，N+1 Equation (10)

[0131] And the rotation angle should satisfy:

[0132]

[0133] Therefore, the appropriate rotation angle for:

[0134]

[0135] Wherein N is the number of columns in a pattern (eg, a matrix) formed by the detection spots, or the number of detection spots in a row in a pattern formed by the detection spots.

[0136] In some embodiments, the detection spots may preferably be arranged in an N×N matrix or hexagonal shape to achieve a better fill factor of the circular optical aberration free area of ​​each detection spot. In this way, the rotation angle will remain

[0137] Fig.10 is based on Fig. 8A , 8B 9 and 1000 are flow charts of a multi-beam scanning method 1000 of an embodiment. For example, the method 1000 can be used in an electron beam tool 40 to improve system throughput. Fig.10 , method 1000 includes the following steps.

[0138] In step 1010, an electron beam tool (e.g., Figure 1 and 2 The electron beam tool 40) generates an array of primary beam waves and projects them onto the sample (e.g., Figure 2 The primary beam forms a detection spot array in the area to be inspected. The detection spot array forms a predetermined pattern, such as an N×N matrix. In some embodiments, each column of the N×N matrix can be aligned with the moving direction of the sample.

[0139] In step 1020, the electron beam tool directs a primary beam array about a primary optical axis (eg, Figure 2 The rotation can be similar to Fig. 9 The rotation is performed relative to the sample. In various embodiments, the electron beam tool can perform the rotation by controlling the deflection scanning unit 232 to rotate the primary beam, rearranging the array of image forming elements in the electron beam tool 40, or rotating the sample. The rotation angle can be set to be equal to wait.

[0140] In step 1030, the electron beam tool deflects the primary beam array to scan across the field of view of the tool. When the beam is rotated, the primary beam array may be able to scan along non-overlapping and longer scan lines, such as Figure 8B and 11 Adjacent scan lines may be separated by a distance corresponding to the pixel size of the image generated by the electron beam tool.

[0141] In step 1040, after scanning the area of ​​the sample below the field of view, the electron beam tool moves the unscanned area of ​​the sample into the field of view. Figure 3A As shown, at the end of T3, the detection spots 310A-310D may move to the next unscanned area including sub-areas 301D, 302D, 303D, 304D, etc. Therefore, step 1030 may be repeated to continue scanning the unscanned area.

[0142] In the disclosed embodiment, steps 1030 and 1040 may be repeated until the entire sample has been inspected. Thus, it may be desirable to operate the electron beam tool in a "step-and-scan" mode, in which the sample stage (e.g., motorized stage 209) stays at a particular position while the primary beam array is deflected to scan an area in the field of view (step 1030) and moved (or "stepped") to the next position so that the unscanned area "jumps" into the electron beam tool's field of view (step 1030). For example, in combination with Figure 3A and 3B As described above, at the end of time period T3, a movement of 10W in the -y direction can be achieved by moving the sample in the y direction. However, since in the "step and scan" mode the scan repeatedly waits for the sample stage to step and stabilize, the "step and scan" mode is usually slower than the "continuous scan" mode, in which the sample stage moves continuously at a slower speed while the primary beam is deflected to scan the sample.

[0143] To allow the above beam rotation method to be used with a faster "continuous scan" mode, the rotated primary beam can be configured to scan the sample using an interlaced scan pattern, such as Fig.11 As stated, Fig.11 FIG. 2 shows an exemplary multi-beam interlaced scanning pattern according to an embodiment of the present disclosure. Fig.11 As shown, in Fig. 8A and 8B After the detection spots 810A-810D in the image are rotated, the electron beam tool can control the primary beam wave so that: the detection spot 810A moves along scan lines 1, 5, 9, 13, 17, etc.; the detection spot 810B moves along scan lines 2, 6, 10, 14, 18, etc.; the detection spot 810C moves along scan lines 3, 7, 11, 15, 19, etc.; the detection spot 810D moves along scan lines 4, 8, 12, 16, 20, etc. These scan lines are substantially parallel to each other. In this way, the detection spots 810A-810D can move between different scan lines while the sample stage is continuously moving. By using this technique, large "jumps" of the sample stage can be avoided.

[0144] Fig.11 An exemplary movement trajectory of the detection spot relative to the absolute reference system is shown on the right side of . The trajectory can be divided into four stages. In stage 1, the detection spot follows the movement of the sample and scans in a first direction. In stage 2, the movement of the detection spot is opposite to the movement direction of the sample, thereby reaching the starting point of the second scan line. In stage 3, the detection spot follows the movement of the sample and scans in a second direction. In stage 4, the movement of the detection spot is opposite to the movement direction of the sample, thereby reaching the starting point of the third scan line. These four stages are repeated during interlaced scanning.

[0145] Fig.12 Shown according to Fig.11 The illustrated embodiment shows an exemplary movement trajectory of the detection spots 810A-810D relative to the sample during interlaced scanning. Fig.12 , the movement tracks 81, 82, 83 and 84 correspond to the detection spots 810A-810D, respectively. Each of the movement tracks 81, 82, 83 and 84 has a continuous pattern formed during the continuous movement of the sample.

[0146] Although interlaced scanning is used in combination with beam rotation in the above-described embodiments, it is contemplated that interlaced scanning may also be applied to multi-beam scanning without beam rotation. Fig.13 is a schematic diagram showing a multi-beam interlaced scanning pattern without beam rotation according to an embodiment of the present disclosure. Fig.13 , the detection spots 810A-810D are arranged in a 2×2 matrix, and each column of the matrix is ​​aligned with the moving direction of the sample. That is, the pattern of detection spots 810A-810D does not rotate relative to the sample. Fig.13When the sample moves continuously in the direction (downward direction shown), any unscanned area in the area 800 first enters the field of view of the detection spots 810A and 810B, and then enters the field of view of the detection spots 810C and 810D. Each detection spot 810A-810D can form a scan line on the area 800. By appropriately controlling the beam distance between the detection spots 810A and 810C along the direction of sample movement, that is, the beam pitch, the scan line formed by the detection spots 810A and 810C can have an interlaced scanning pattern. Similarly, by appropriately controlling the beam distance between the detection spots 810B and 810D along the direction of sample movement, that is, the beam pitch, the scan line formed by the detection spots 810B and 810D has an interlaced scanning pattern. Through interlaced scanning, multi-beam scanning can be combined with a fast "continuous scanning mode" with or without beam rotation. Therefore, the system output is improved. In addition, since beam rotation is not required, detectors associated with beam rotation (for example, Figure 2 The complexity of the electronic detector 240).

[0147] Fig.14 is based on Figure 11-13 Flowchart of a multi-beam interlacing method 1400 of the illustrated embodiment. For example, the method 1400 may be used in an electron beam tool 40 to improve system throughput. Fig.14 , method 1400 includes the following steps.

[0148] In step 1410, an electron beam tool (e.g., Figure 1 and 2 The electron beam tool 40) generates an array of N primary beam waves and projects them onto the sample (e.g., Figure 2 The primary beam forms an array of N detection spots in the area to be inspected.

[0149] In step 1420, the electron beam tool controls the sample to move continuously. For example, the electron beam tool can control the stage (e.g., Figure 2 The motorized stage 209) continuously moves the sample.

[0150] In step 1430, if Figure 11-13 As shown, the electron beam tool deflects N primary beams to simultaneously i) follow the movement of the sample and ii) scan N scan lines respectively over the sample surface.

[0151] In step 1440, after scanning N scan lines, the electron beam tool deflects N primary beams relative to the sample in a direction opposite to the sample movement direction through the N scan lines, so that the detection spot formed by the primary beam arrives at the starting point of a new set of scan lines. According to the disclosed embodiment, steps 1430 and 1440 are repeatedly performed to form an interlaced scanning pattern, for example, Figure 11-13 The interlaced scanning pattern shown.

[0152] As described above, in order to form an interlaced scanning pattern, it may be necessary for the primary beam waves or corresponding detection spots to be finely spaced. For example, for a beam pitch of 10 μm, it may be necessary to limit the beam alignment error to within 1 nm to avoid unnecessary gaps between adjacent detection spots (which prevents part of the sample from being scanned). In order to relax the requirements on beam alignment, semi-interlaced scanning can be used in some embodiments.

[0153] Fig.15 is a schematic diagram showing a multi-beam half-interlaced scanning pattern according to an embodiment of the present disclosure. Fig.15 As shown, each detection spot 810A-810D is allowed to first continuously perform an xy scan (e.g., scan multiple scan lines) in a small area while the sample stage is continuously moving. After the xy scan is completed, the sample makes a small "jump" to move to the next unscanned area in the field of view of the detection spots 810A-810D. In this way, the area scanned by the detection spots 810A and 810C can form an interlaced scanning pattern, and the area scanned by the detection spots 810B and 810D can form an interlaced scanning pattern.

[0154] Semi-interlaced scanning uses appropriate spacing between detection spots 810A and 810C and between detection spots 810B and 810D. However, beam alignment is less critical in semi-interlaced scanning than in interlaced scanning because it allows for some overlap of interlaced areas. Also, the sample stage makes relatively smaller "jumps" in semi-interlaced scanning than in typical "step-and-scan" mode, and therefore spends less time jumping and settling. Therefore, semi-interlaced scanning can improve system throughput.

[0155] Fig.16 is a flowchart of a multi-beam semi-interlaced scanning method according to an embodiment of the present disclosure. For example, method 1600 can be used for an electron beam tool (e.g., Figure 1 and 2 Electron beam tools 40) to improve system output. Fig.16 , method 1600 includes the following steps.

[0156] In step 1610, the electron beam tool generates an array of N primary beam waves and projects them onto the sample (e.g., Figure 2The primary beam forms an array of N detection spots in the area to be inspected.

[0157] In step 1620, the electron beam tool controls the sample to move continuously. For example, the electron beam tool can control the stage (e.g., Figure 2 The motorized stage 209) continuously moves the sample.

[0158] In step 1630, if Fig.15 As shown, the electron beam tool deflects N primary beams to simultaneously i) follow the movement of the sample and ii) scan M scan lines on the sample surface within the field of view of each beam. M is an integer equal to or greater than 2.

[0159] In step 1640, if Fig.15 As shown, after N primary beams scan a set of M scan lines in their respective fields of view, the electron beam tool moves the sample to expose the unscanned area to the fields of view of the N primary beams. In some embodiments, the electron beam tool can move the sample by M scan lines. In this way, the area scanned by the primary beams can form an interlaced scan pattern.

[0160] According to the disclosed embodiment, steps 1630 and 1640 are repeatedly performed so that a similar Fig.15 The interlaced scanning pattern shown. In addition, Fig.15 and 16 The semi-interlaced scanning process shown can be used with or without beam rotation.

[0161] As mentioned above, continuous scan mode is generally faster than step scan mode and therefore can achieve higher throughput. Fig.17 is a schematic diagram showing the distribution of multiple primary beams in a continuous scanning mode according to an embodiment of the present disclosure. Fig.17 , electron beam tools (e.g., Figure 1 and 2 The electron beam tool 40) may have nine primary beam waves 171, 172, 173, ..., and 179. In some embodiments, in order to make the electron beam tool suitable for continuous scanning mode, the nine primary beam waves may be arranged in a straight line perpendicular to the direction of sample movement and separated by equal distances (see Fig.17 In this way, each primary beam can continuously scan the sample without any jumps. Fig. 8A and 8BAs mentioned, in this arrangement, the fields of view of the detection spots overlap, so the system throughput is not maximized. To improve the system throughput, some or all of the primary beams can be repositioned relative to the other primary beams along the direction of sample movement to effectively increase the beam distance in the direction perpendicular to the sample (see Fig.17 ). Thus, similar to Fig. 8A and 8B By rotating the beam as shown, each primary beam can scan a longer scan line. Furthermore, to operate the electron beam tool in a continuous scan mode, the electron beam tool can control the repositioned primary beam to match the Figure 7 Interlaced scanning is performed in a manner similar to that shown in FIG. 8 .

[0162] Fig.17 The embodiments in can also be adapted to include multiple primary beams arranged along the sample moving direction. Fig.18 The electron beam tool may further include primary beams 181-189, which are aligned with the primary beams 171-179 along the sample movement direction and are spaced equidistant from the primary beams 171-179 along the sample movement direction. Each pair of primary beams arranged in a row along the sample movement direction may be controlled similar to Fig.15 The semi-interlaced scanning is performed in the manner shown to reduce or avoid large jumps. Alternatively, the group of primary beams 171-179 and the group of primary beams 181-189 can be respectively interlaced ( Fig.18 ), in which case each pair of primary beams aligned along the sample movement direction scans the same area in sequence and frame averaging can therefore be performed.

[0163] Reference now Fig.19 , Fig.19 is a schematic diagram showing an exemplary scanning pattern using a set of rotating primary beams according to an embodiment of the present disclosure. As previously described, in order to achieve higher system throughput, it is desirable for each primary beam to scan a longer scan line. Maintaining continuous and constant movement of the sample during inspection can also increase the throughput of the inspection system (e.g., the continuous scanning mode described in the previous section).

[0164] Fig.19 A multi-beam inspection system is shown having a 3×3 array of primary beam waves that produces nine detection spots 1901, 1902, ..., 1909 arranged in a 3×3 matrix configuration. Similar to the previous embodiment, the sample (e.g., Figure 2The sample 208) can be moved in the y direction at a constant speed K. In some embodiments, the 3×3 array of primary beams can be rotated by a specific angle relative to the sample movement direction. The rotation angle can be determined by the number of primary beams in a row (e.g., three in a 3×3 array configuration), as described with respect to Fig. 9 As described in equation (12). In some embodiments, the sample can be rotated by a rotation angle such that the detection spot is effectively rotated relative to the sample movement direction. In some embodiments, the beam and the sample can be rotated simultaneously, resulting in the beam rotating by a rotation angle relative to the sample movement direction.

[0165] In some embodiments, the detection spots 1901-1909 can scan the sample in a direction perpendicular to the direction of sample movement. For example, the detection spots 1901-1909 can be scanned in the x-direction as shown by arrows 1921-1929 while the sample moves in the y-direction. In such an embodiment, the scan width of the primary beam can be determined by how wide the sample can be scanned by each primary beam without causing too much overlap between areas scanned by adjacent primary beams (e.g., the movement span of the detection spot 1901, as shown by the length of arrow 1921). Even if the rotating beam configuration can support a continuous scanning mode, the relatively short scan width in the x-direction may still limit the improvement of system throughput because the overhead of the scanning pattern (e.g., the relative percentage of non-scanning beam movement relative to scanning beam movement) may be high.

[0166] In some embodiments, the detection spots 1901-1909 can scan the sample in a direction parallel to the direction of sample movement. For example, the detection spots 1901-1909 can move in the y direction as shown by arrows 1931-1939 while the sample is also moving in the y direction. In such embodiments, the scan width of the primary beam is not limited by the configuration of the primary beam (e.g., pitch or rotation angle) because increasing the scan width will not produce any overlap between areas scanned by adjacent beams. Also, the increased scan width can improve system throughput because the overhead of the scan pattern can be greatly reduced.

[0167] although Fig.19 A configuration of a primary beam with 9 detection spots 1901-1909 arranged in a 3×3 matrix is ​​shown, but it should be understood that the principles disclosed herein can be applied to any number and configuration of primary beams, such as primary beams arranged in a 3×2, 4×4, 5×5, 3×5, 8×5, 20×20 or any size matrix configuration.

[0168] Reference now Fig. 20A , 20B , 20C and 20D, Fig. 20A , 20B20C and 20D are diagrams showing the use of an embodiment according to the present disclosure. Fig.19 Schematic diagram of an exemplary multi-beam scanning pattern of a rotating primary beam wave shown in FIG. In some embodiments, the scanning direction of the detection spots 1901-1909 is parallel to the sample movement direction. In such an embodiment, each detection spot scans a plurality of scanning segments positioned along the sample movement direction. For example, Fig. 20A As shown, the first row scanning segment (e.g., scanning segments 2011, 2021, etc.) can be scanned by a primary beam wave corresponding to the detection spot 1901. Similarly, the second row scanning segment (e.g., scanning segments 2012, 2022, etc.) can be scanned by a primary beam wave corresponding to the detection spot 1902. Similarly, the third, fourth, fifth, sixth, seventh, eighth, and ninth row scanning segments can be scanned by the detection spots 1903, 1904, 1905, 1906, 1907, 1908, and 1909, respectively.

[0169] In some embodiments, each scanning segment is scanned in a raster scanning pattern. For example, within portion 2011, detection spot 1901 may scan a scan line via scan path 2071 and then return to the other side via retrace path 2072 to begin scanning the next scan line. These steps may be repeated until all scan lines of the scanning segment are scanned. Fig. 20A A raster scan pattern within each scan segment is shown, but it should be understood that any other scanning method may be used to scan each scan segment. For example, in some embodiments, the detection spot 1901 may scan and retrace in opposite directions, e.g., scanning from right to left and retrace from left to right.

[0170] In some embodiments, the detection spots 1901-1909 may first scan a first set of scanning segments (e.g., scanning segments 2011, 2012, 2013, ..., 2019). After the scanning of the first set of scanning segments is completed, the detection spots 1901-1909 may be repositioned to prepare for scanning a second set of scanning segments (e.g., scanning segments 2021, 2022, 2023, ..., 2029). Fig. 20B As shown, repositioning of the primary beam can involve moving each detection spot from the position where the scan of the first group ends to the position where the scan of the second group will begin, as shown by arrows 2081, 2082, 2083, ..., 202b, 208b. After repositioning, the detection spots 1901-1909 can begin scanning the second group of scan segments. In some embodiments, the scanning and repositioning steps can be repeated until the entire sample area of ​​interest has been scanned and examined. Although Fig. 20BThe scan of the first group is shown ending at the rightmost corner, but it should be understood that the end point of the scan can be different depending on the various scan patterns used. For example, as described in the previous section, if the scan and retrace are performed using opposite directions (e.g., scanning from right to left and retrace from left to right), the scan of the first group can end at the leftmost corner. In this case, the repositioning distance can be shorter.

[0171] To avoid any gaps in the scan data between adjacent scan segments (e.g., between scan segments 2011 and 2021) that may be introduced during repositioning of the primary beam, the adjacent scan segments may partially overlap. Fig. 20C As shown, scanning segments 2011 and 2021 may partially overlap, thereby generating overlapping region 2091. Similarly, scanning segments 2012 and 2022 may generate overlapping region 2092. These overlapping regions may be scanned two or more times. For example, overlapping region 2091 may be first scanned during scanning of scanning segment 2011, and then scanned a second time during scanning of scanning segment 2021. A controller (e.g., Figure 2 A controller 50) can collect scan data, including multiple scan data from each overlapping area, and process the scan data to produce a continuous image of the sample for inspection.

[0172] In some embodiments, the scanning and repositioning steps can be performed while the stage that holds the sample is continuously moving at a constant speed. In such embodiments, the movement of the detection spot can be adjusted to accommodate the continuous movement of the stage. For example, Fig.20D The movement of the probe spot 1901 relative to a fixed position of the multi-beam inspection tool over time is shown as scanning occurs while the sample moves continuously in the y-direction. In such a case, the path of the beam used for the scanning step (e.g., scanning path 2071) and the path of the beam used for the retrace step (e.g., retrace path 2072) can be adjusted to accommodate the movement of the stage. For example, the scanning path 2071 can be extended because the sample is also moving in the same direction. The retrace path 2072 can be shortened because the sample is moving in an opposite direction relative to the retrace direction, for example, the sample may have moved to the right when the probe spot 1901 retrace to the left.

[0173] As described with respect to earlier embodiments, in some embodiments, the controller can control the movement of the primary beam and the stage so that the primary beam can only repeat the movement pattern. Where the controller controls the speed of scanning, retrace, repositioning, and stage movement, the detection spot 1901 can continuously repeat the movement pattern, such as Fig. 20B shown.

[0174] For example, about Fig.20D, at T1, the detection spot 1901 is located at position A to start scanning the scan segment 2011. During the time period from T1 to T2, the detection spot 1901 performs scanning and retracement, and the sample continues to move in the y direction until the detection spot 1901 completes the scanning of the last scan line of the portion. At T2, the detection spot 1901 reaches position B when the scanning of the scan segment 2011 is completed. During the time period from T2 to T3, the detection spot 1901 is repositioned back to position A, and the sample continues to move in the y direction. At T3, the detection spot 1901 is repositioned back to position A. At the same time, at T3, the next scan segment (for example, the scan segment 2021) moves in, and the upper left corner of the scan segment 2021 (where the scan within the portion starts) can be aligned with portion A. Therefore, in this case, the detection spot 1901 can simply continuously repeat the movement pattern between position A and position B, such as Fig.20D As the detection spot 1901 repeatedly moves in this manner, the detection spot 1901 can continuously scan the scanning segments of the corresponding row (for example, the scanning segments 2011, 2021, 2031, etc.).

[0175] although Fig. 20A , 20B and 20C show a configuration of a primary beam having 9 detection spots 1901-1909 arranged in a 3×3 matrix. It should be understood that the principles disclosed herein can be applied to any number and configuration of primary beams, such as primary beams arranged in a matrix configuration of 3×2, 4×4, 5×5, 3×5, 8×5, 20×20 or any size.

[0176] The embodiments may be further described using the following terms:

[0177] 1. A multi-beam tool comprising:

[0178] A beam configuration system comprising: a charged particle source for generating a primary beam of charged particles; a stage for holding a sample; and a deflector system located between the charged particle source and the stage and configured to divide the primary beam into a beam array,

[0179] Wherein the beam configuration system is configured to provide a rotated beam configuration having a rotation angle determined based on the number of beams in a row of the beam array.

[0180] 2. A multi-beam tool according to clause 1, wherein:

[0181] The beam array is disposed about an optical axis of the multi-beam tool; and

[0182] The rotating beam configuration includes the stage being configured to rotate about the optical axis.

[0183] 3. The multi-beam tool of clause 1, wherein:

[0184] The beam array is disposed about an optical axis of the multi-beam tool; and

[0185] The rotating beam configuration includes the deflector system being configured to rotate the beam array about the optical axis.

[0186] 4. A multi-beam tool according to any one of clauses 1 to 3, wherein:

[0187] The multi-beam tool is configured to generate an image of a surface area of ​​the sample; and

[0188] The rotating beam configuration enables the beam array to scan an area larger than the surface area imaged.

[0189] 5. A multi-beam tool according to any one of clauses 1 to 4, wherein:

[0190] The stage is configured to move along a first direction; and

[0191] Scanning of the beam array across the field of view includes scanning of the beam array to cover a set of scan lines along a second direction across the field of view.

[0192] 6. The multi-beam tool of clause 5, wherein the second direction is substantially perpendicular to the first direction relative to the sample.

[0193] 7. The multi-beam tool of clause 5, wherein the second direction is substantially parallel to the first direction relative to the sample.

[0194] 8. A multi-beam tool according to any of clauses 5 to 7, wherein the set of scan lines are spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0195] 9. The multi-beam tool according to any one of clauses 1 to 8, wherein the beam configuration system further comprises a controller coupled to the stage, the controller being configured to control movement of the stage.

[0196] 10. A multi-beam tool according to any one of clauses 1 to 9, wherein the beam configuration system further comprises a controller coupled to the deflector system, the controller being configured to control the deflector system to deflect the beam array.

[0197] 11. A multi-beam tool comprising:

[0198] Bundle configuration system, including:

[0199] A charged particle source for generating a primary beam of charged particles; a stage configured to hold a sample and configured to move in a first direction; and a deflector system located between the charged particle source and the stage, the beam configuration system being configured to:

[0201] Divide the primary beam into n beams, where n is an integer and n≥2;

[0202] rotating the n beams with respect to the first direction so that the n beams are spaced apart along the first direction;

[0203] The n beams are deflected to simultaneously i) follow the movement of the stage and ii) scan one or more sets of n scan lines over the surface of the sample.

[0204] 12. The multi-beam tool according to clause 11, wherein

[0205] The one or more groups of n scan lines include a first group of n scan lines spread over a first distance along the first direction; and

[0206] The bundle configuration system is further configured to:

[0207] After the first set of n scan lines are scanned, shifting the n beams by the first distance in a direction opposite to the first direction; and

[0208] The n beams are deflected to simultaneously i) follow the movement of the stage and ii) scan a second set of n scan lines over the surface of the sample.

[0209] 13. The multi-beam tool of clause 12, wherein the first and second sets of n scan lines are substantially parallel lines.

[0210] 14. A multi-beam tool according to any of clauses 12 and 13, wherein each scan line of the first and second sets of n scan lines are spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0211] 15. A multi-beam tool according to any of clauses 11 to 14, wherein the one or more groups of n scan lines are along a second direction substantially perpendicular to the first direction relative to the sample.

[0212] 16. A multi-beam tool according to any of clauses 11 to 14, wherein the one or more groups of n scan lines are along a second direction substantially parallel to the first direction relative to the sample.

[0213] 17. A multi-beam tool according to any one of clauses 11 to 16, wherein:

[0214] The n beams are projected onto the surface of the sample and form n detection spots on the surface; and

[0215] The n beams following the movement of the stage comprises: the n detection spots moving in the first direction at the same speed as the stage.

[0216] 18. A multi-beam tool according to any of clauses 11 to 17, wherein the stage moves at a constant speed.

[0217] 19. The multi-beam tool according to any one of clauses 11 to 18, wherein the beam configuration system is configured to:

[0218] The n beams are rotated at a rotation angle determined based on the number of beams in a row of the n beams.

[0219] 20. The multi-beam tool of clause 19, wherein:

[0220] The n beams are arranged around an optical axis of the multi-beam tool; and

[0221] The beam configuration system being configured to rotate the n beams includes: the beam configuration system being configured to rotate the stage around the optical axis.

[0222] 21. The multi-beam tool of clause 19, wherein:

[0223] The n beams are arranged around an optical axis of the multi-beam tool; and

[0224] The beam configuration system being configured to rotate the n beams comprises: the deflector system being configured to rotate the n beams around the optical axis.

[0225] 22. The multi-beam tool according to any one of clauses 11 to 21, wherein the beam configuration system further comprises a controller coupled to the stage, the controller being configured to control the movement of the stage.

[0226] 23. The multi-beam tool according to any one of clauses 11 to 22, wherein the beam configuration system further comprises a controller coupled to the deflector system, the controller being configured to control the deflection of the n beams.

[0227] 24. A multi-beam tool comprising:

[0228] A beam configuration system comprising: a charged particle source configured to generate a primary beam of charged particles; a stage configured to hold a sample and configured to move in a first direction; and a deflector system located between the charged particle source and the stage and configured to split the primary beam into a beam array,

[0229] The bundle configuration system is configured as follows:

[0230] deflecting the beam array via the deflector system to i) scan a first set of scan lines in a field of view of the beam configuration system, and ii) follow movement of the stage during the scanning of the first set of scan lines, wherein the first set of scan lines are spread over a first distance along the first direction;

[0231] After the first group of scan lines are scanned, moving the stage in the first direction by the first distance;

[0232] deflecting the beam array via the deflector system to i) scan a second set of scan lines in the field of view of the beam configuration system, and ii) follow the movement of the stage during the scanning of the second set of scan lines, and

[0233] The stage is moved in the first direction while the first and second sets of scan lines are scanned.

[0234] 25. The multi-beam tool of clause 24, wherein:

[0235] The array of beams includes a first beam; and

[0236] wherein the beam configuration system is configured to deflect the beam array via the deflector system to i) scan a first set of scan lines in a field of view of the beam configuration system, and ii) follow the movement of the stage during the scanning of the first set of scan lines comprises: the beam configuration system is configured to:

[0237] deflecting the first beam to simultaneously i) follow the movement of the stage, and ii) scan a first scan line;

[0238] After the first scan line is scanned, deflecting the first beam by a predetermined distance in a direction opposite to the first direction; and

[0239] The first beam is deflected to simultaneously i) follow the movement of the stage, and ii) scan a second scan line.

[0240] 26. The multi-beam tool according to any of clauses 24 and 25, wherein the beam configuration system is further configured to:

[0241] projecting the array of beams onto a surface of the sample to form an array of detection spots on the surface,

[0242] Wherein the beam array following the movement of the stage comprises: the detection spot array moves in the first direction at the same speed as the stage.

[0243] 27. The multi-beam tool according to any of clauses 24 to 26, wherein during said scanning of said first and second sets of scan lines, said beam configuration system is further configured to move said stage in said first direction at a constant speed.

[0244] 28. A multi-beam tool according to any of clauses 24 to 27, wherein each scan line of the first and second sets of scan lines are spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0245] 29. A multi-beam tool according to any of clauses 24 to 28, wherein the first and second sets of scan lines are substantially perpendicular to the first direction relative to the sample.

[0246] 30. The multi-beam tool according to any of clauses 24 to 29, wherein the first and second sets of scan lines are substantially parallel lines.

[0247] 31. The multi-beam tool of any of clauses 24 to 30, wherein the beam configuration system further comprises a controller coupled to the stage, the controller being configured to control the movement of the stage.

[0248] 32. The multi-beam tool according to any one of clauses 24 to 31, wherein the beam configuration system further comprises a controller coupled to the deflector system, the controller being configured to control the deflection of the beam array.

[0249] 33. A method comprising:

[0250] generating a primary beam of charged particles by a multibeam tool;

[0251] dividing the primary beam into a beam array by the multi-beam tool; and

[0252] The beam array is rotated by the multi-beam tool relative to a sample to be scanned by a rotation angle determined based on the number of beams in a row of the beam array.

[0253] 34. The method of clause 33, wherein rotating the beam array relative to the sample comprises rotating the sample about an optical axis of the multi-beam tool.

[0254] 35. The method of clause 33, wherein rotating the beam array relative to the sample comprises rotating the beam array about an optical axis of the multi-beam tool.

[0255] 36. A method according to any of clauses 33 to 35, wherein rotating the beam array relative to the sample enables the beam array to scan an area larger than the sample surface area imaged by the multi-beam tool.

[0256] 37. A method according to any one of clauses 33 to 36, further comprising:

[0257] The sample is moved in a first direction by the multi-beam tool,

[0258] Wherein the beam array scans a set of scan lines covering the imaged surface area along a second direction.

[0259] 38. The method of clause 37, wherein the second direction is substantially perpendicular to the first direction relative to the sample.

[0260] 39. The method of clause 37, wherein the second direction is substantially parallel to the first direction relative to the sample.

[0261] 40. A method according to any of clauses 37 to 39, wherein the set of scan lines are spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0262] 41. A method comprising:

[0263] moving the sample in a first direction by a multi-beam tool;

[0264] generating a primary beam of charged particles by the multi-beam tool;

[0265] Splitting the primary beam into n beams by the multi-beam tool, wherein n is an integer and n≥2;

[0266] rotating the n beams with reference to the first direction by the multi-beam tool so that the n beams are spaced apart along the first direction;

[0267] The n beams are deflected by the multi-beam tool to simultaneously i) follow the movement of the sample, and ii) scan one or more sets of n scan lines over the surface of the sample.

[0268] 42. The method of clause 41, wherein the one or more groups of n scan lines include a first group of n scan lines spread over a first distance along the first direction, the method further comprising:

[0269] After the first set of n scan lines are scanned, offsetting the n beams by the multi-beam tool in a direction opposite to the first direction by the distance; and

[0270] The n beams are deflected by the multi-beam tool to simultaneously i) follow the movement of the sample, and ii) scan a second set of n scan lines over the surface of the sample.

[0271] 43. The method of clause 42, wherein the first and second sets of n scan lines are substantially parallel lines.

[0272] 44. A method according to any of clauses 42 and 43, wherein each scan line in the first and second sets of n scan lines is spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0273] 45. A method according to any one of clauses 42 to 44, wherein the one or more groups of n scan lines are along a second direction substantially perpendicular to the first direction relative to the sample.

[0274] 46. ​​A method according to any of clauses 42 to 44, wherein the one or more groups of n scan lines are along a second direction substantially parallel to the first direction relative to the sample.

[0275] 47. A method according to any of clauses 45 to 46, wherein the first set of n scan lines covers a field of view of the multi-beam tool along the second direction.

[0276] 48. A method according to any of clauses 42 to 47, wherein the n beams are projected onto the surface of the sample and form n detection spots on the surface, the method further comprising:

[0277] The n beams are deflected to allow the n detection spots to move in the first direction at the same speed as the sample.

[0278] 49. The method of any one of clauses 42 to 48, wherein moving the sample in the first direction comprises moving the sample in the first direction at a constant speed.

[0279] 50. A method comprising:

[0280] moving the sample in a first direction;

[0281] generating a primary beam of charged particles by a multibeam tool;

[0282] dividing the primary beam into a beam array by the multi-beam tool;

[0283] deflecting the beam array by the multi-beam tool to i) scan a first set of scan lines in a field of view of the multi-beam tool, and ii) follow movement of the sample during the scanning of the first set of scan lines, wherein the first set of scan lines are spread over a first distance along the first direction;

[0284] after the first set of scan lines are scanned, moving the sample by the multi-beam tool in the first direction by the first distance;

[0285] deflecting the beam array by the multi-beam tool to i) scan a second set of scan lines in a field of view of the multi-beam tool, and ii) follow movement of the sample during the scanning of the second set of scan lines; and

[0286] The sample is moved in the first direction by the multi-beam tool while the first and second sets of scan lines are scanned.

[0287] 51. The method of clause 50, wherein deflecting the beam array to i) scan the first set of scan lines in the field of view of the multi-beam tool, and ii) follow the movement of the sample during the scanning of the first set of scan lines comprises:

[0288] deflecting a first beam in the array of beams to simultaneously i) follow the movement of the sample, and ii) scan a first scan line;

[0289] After the first scan line is scanned, deflecting the first beam by a predetermined distance in a direction opposite to the first direction; and

[0290] The first beam is deflected to simultaneously i) follow the movement of the sample, and ii) scan a second scan line.

[0291] 52. A method according to any one of clauses 50 and 51, wherein deflecting the beam array to follow the movement of the sample includes: deflecting the beam array to allow the array of detection spots formed by the beam array on the sample to move in the first direction at the same speed as the sample.

[0292] 53. The method according to any one of clauses 50 to 52, further comprising:

[0293] During the scanning of the first and second sets of scan lines, the sample is moved in the first direction at a constant speed.

[0294] 54. A method according to any of clauses 50 to 53, wherein each scan line in the first and second sets of scan lines is spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0295] 55. A method according to any one of clauses 50 to 54, wherein the first and second sets of scan lines are substantially perpendicular to the first direction relative to the sample.

[0296] 56. A method according to any of clauses 50 to 55, wherein the first and second sets of scan lines are substantially parallel lines.

[0297] 57. A non-transitory computer readable medium having stored thereon a set of instructions executable by a controller coupled to a multi-beam tool to cause the controller to perform a method comprising:

[0298] instructing, by the multi-beam tool, a beam configuration system of the multi-beam tool to rotate a charged particle beam array relative to a sample to be scanned by a rotation angle determined based on the number of beams in a row of the beam array,

[0299] Wherein the multi-beam tool generates a primary beam of charged particles and splits the primary beam into an array of charged particle beams.

[0300] 58. The medium of clause 57, wherein the array of charged particle beams is disposed about an optical axis of the multi-beam tool, wherein the set of instructions further causes the controller to perform:

[0301] A sample stage of the multi-beam system is instructed to rotate the sample about the optical axis.

[0302] 59. The medium of clause 57, wherein the beam array is disposed about an optical axis of the multi-beam tool, wherein the set of instructions further causes the controller to perform:

[0303] The beam configuration system is instructed to rotate the charged particle beam array about the optical axis.

[0304] 60. The medium of any of clauses 57 to 59, wherein the set of instructions further causes the controller to perform:

[0305] controlling the multi-beam tool to generate an image of a surface area of ​​the sample; and

[0306] The beam configuration system is instructed to move the charged particle beam array over an area larger than the surface area being imaged.

[0307] 61. The medium of clause 60, wherein the set of instructions further causes the controller to perform:

[0308] instructing a sample stage of the multi-beam tool to move the sample in a first direction; and

[0309] The beam configuration system is instructed to move the charged particle beam array to scan a set of scan lines covering the field of view along a second direction.

[0310] 62. A medium according to clause 61, wherein the second direction is substantially perpendicular to the first direction relative to the sample.

[0311] 63. A medium according to clause 61, wherein the second direction is substantially parallel to the first direction relative to the sample.

[0312] 64. A medium according to any of clauses 61 to 63, wherein the set of scan lines are spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0313] 65. A non-transitory computer readable medium having stored thereon a set of instructions executable by a controller coupled to a multi-beam tool to cause the controller to perform a method comprising:

[0314] instructing a sample stage of the multi-beam tool to move a sample in a first direction, the multi-beam tool generating a primary beam of charged particles and splitting the primary beam into n beams, where n is an integer and n≥2;

[0315] instructing a beam configuration system of the multi-beam tool to rotate the n beams relative to the first direction so that the n beams are spaced apart along the first direction;

[0316] The beam configuration system is instructed to deflect the n beams to simultaneously i) follow the movement of the sample, and ii) scan one or more sets of n scan lines over the surface of the sample.

[0317] 66. The medium of clause 65, wherein the one or more groups of n scan lines include a first group of n scan lines spread over a first distance along the first direction, wherein the set of instructions further causes the controller to perform:

[0318] After the first set of n scan lines are scanned, instructing the beam configuration system to shift the n beams by the distance in a direction opposite to the first direction; and

[0319] The beam configuration system is instructed to deflect the n beams to simultaneously i) follow the movement of the sample, and ii) scan a second set of n scan lines over the surface of the sample.

[0320] 67. The medium of clause 66, wherein the first and second sets of n scan lines are substantially parallel lines.

[0321] 68. A medium according to any of clauses 66 and 67, wherein each scan line in the first and second groups of n scan lines is spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0322] 69. The medium of any of clauses 65 to 68, wherein the set of instructions further causes the controller to execute:

[0323] The beam configuration system is instructed to move the one or more groups of n scan lines relative to the sample in a second direction substantially perpendicular to the first direction.

[0324] 70. The medium of any of clauses 65 to 68, wherein the set of instructions further causes the controller to perform:

[0325] The beam configuration system is instructed to move the one or more groups of n scan lines relative to the sample in a second direction substantially parallel to the first direction.

[0326] 71. A medium according to any of clauses 69 and 70, wherein the first set of n scan lines covers a field of view of the multi-beam tool along the second direction.

[0327] 72. A medium according to any of clauses 65 to 71, wherein the n beams are projected onto the surface of the sample and form n detection spots on the surface, wherein the set of instructions further causes the controller to execute:

[0328] The beam configuration system is instructed to deflect the n beams to allow the n detection spots to move in the first direction at the same speed as the sample.

[0329] 73. The medium of any of clauses 65 to 72, wherein the set of instructions further causes the controller to perform:

[0330] The sample stage is instructed to move the sample in the first direction at a constant speed.

[0331] 74. A non-transitory computer readable medium having stored thereon a set of instructions executable by a controller coupled to a multi-beam tool to cause the controller to perform a method comprising:

[0332] instructing a sample stage of the multi-beam tool, which generates a primary beam of charged particles and divides the primary beam into an array of beams, to move the sample in a first direction;

[0333] instructing a beam configuration system of the multi-beam tool to deflect the beam array to i) scan a first set of scan lines in a field of view of the multi-beam tool, and ii) follow movement of the sample during the scanning of the first set of scan lines, wherein the first set of scan lines are spread over a first distance along the first direction;

[0334] instructing the sample holder to move the sample in the first direction by the first distance after the first set of scan lines are scanned;

[0335] instructing the beam configuration system to deflect the beam array to i) scan a second set of scan lines in the field of view of the multi-beam tool, and ii) follow movement of the sample during the scanning of the second set of scan lines; and

[0336] The sample holder is instructed to move the sample in the first direction while the first and second sets of scan lines are scanned.

[0337] 75. The medium of clause 74, wherein the array of beams includes a first beam, wherein the set of instructions further causes the controller to instruct the beam configuration system to:

[0338] deflecting the first beam to simultaneously i) follow the movement of the sample, and ii) scan a first scan line;

[0339] After the first scan line is scanned, deflecting the first beam by a predetermined distance in a direction opposite to the first direction; and

[0340] The first beam is deflected to simultaneously i) follow the movement of the sample, and ii) scan a second scan line.

[0341] 76. A medium according to any of clauses 74 and 75, wherein the array of beams is projected onto a surface of the sample and forms an array of detection spots on the surface, wherein the set of instructions further causes the controller to further perform:

[0342] The beam configuration system is instructed to deflect the beam array to allow the array of detection spots to move in the first direction at the same speed as the sample.

[0343] 77. The medium of any of clauses 74 to 76, wherein the set of instructions further causes the controller to perform:

[0344] During the scanning of the first and second sets of scan lines, the sample stage is instructed to move the sample in the first direction at a constant speed.

[0345] 78. A medium according to any of clauses 74 to 77, wherein each of the first and second sets of scan lines are spaced apart by a distance corresponding to a pixel size of an image generated by the multi-beam tool.

[0346] 79. A medium according to any of clauses 74 to 78, wherein the first and second sets of scan lines are substantially perpendicular to the first direction relative to the sample.

[0347] 80. A medium according to any of clauses 74 to 79, wherein the first and second sets of scan lines are substantially parallel lines.

[0348] 81. A method of scanning an area of ​​a sample using N charged particle beams, wherein N is an integer greater than or equal to 2, and wherein the area of ​​the sample comprises a plurality of scan segments of N consecutive scan lines, the method comprising:

[0349] Moving the position of the sample in a first direction;

[0350] Scanning a first scanning line of at least a portion of the scanning sections of the plurality of scanning sections that moves toward a detection spot of the first charged particle beam using a first charged particle beam of the N charged particle beams; and

[0351] A second scan line of at least a portion of the scan sections moving toward a detection spot of the second charged particle beam among the plurality of scan sections is scanned with a second charged particle beam among the N charged particle beams.

[0352] 82. The method of clause 81, wherein moving the position of the sample in the first direction comprises constantly moving the position of the sample at a first speed.

[0353] 83. A method according to any of clauses 81 and 82, wherein the scan line is positioned perpendicular to the first direction.

[0354] 84. A method according to any of clauses 81 and 82, wherein the scan line is tilted away from the first direction to accommodate movement of the position of the sample in the first direction.

[0355] 85. The method of any one of clauses 81 to 84, wherein the first scan line of the plurality of scan segments is positioned parallel to the second scan line of the plurality of scan segments.

[0356] 86. The method according to any one of clauses 81 to 85, further comprising:

[0357] The N charged particle beams are deflected to move the detection spots of the N charged particle beams from respective starting positions to respective ending positions in a second direction to follow the movement of the sample while scanning a set of scan lines.

[0358] 87. The method according to clause 86, further comprising:

[0359] The N charged particle beams are deflected to move the detection spots of the N charged particle beams from the respective end positions to the respective start positions to reposition the detection spots to the respective start positions to prepare for scanning a next set of scan lines.

[0360] 88. A method according to any one of clauses 81 to 87, wherein the second direction is substantially opposite to the third direction.

[0361] 89. A method according to any of clauses 86 to 88, wherein:

[0362] Deflecting the N charged particle beams so that the detection spots of the N charged particle beams move in the second direction comprises: deflecting the N charged particle beams so that the detection spots of the N charged particle beams move in the second direction at a second speed; and

[0363] Deflecting the N charged particle beams to move the detection spots of the N charged particle beams in the third direction includes: deflecting the N charged particle beams to move the detection spots of the N charged particle beams in the third direction at a third speed.

[0364] 90. The method of clause 89, wherein the second speed and the third speed are the same.

[0365] 91. A method according to any one of clauses 82 to 90, wherein the first speed is associated with a size of a scanning segment.

[0366] 92. A method according to any one of clauses 82 to 90, wherein the first speed is determined based on the length of the scan line, the second speed and the third speed.

[0367] 93. A method according to any one of clauses 81 to 92, wherein the sample comprises a wafer or a photomask.

[0368] 94. A non-transitory computer readable medium storing instructions, the instruction set being executable by one or more processors of a charged particle beam system to cause the charged particle beam system to perform a method together with a charged particle beam source for delivering N charged particle beams to a surface of a sample in a time sequence, the method comprising:

[0369] moving the position of the sample in a first direction;

[0370] Scanning a first scanning line of at least a portion of a scanning section of a plurality of scanning sections that moves toward a detection spot of the first charged particle beam using a first charged particle beam of the N charged particle beams; and

[0371] A second scan line of at least a portion of the scan sections moving toward a detection spot of the second charged particle beam among the plurality of scan sections is scanned with a second charged particle beam among the N charged particle beams.

[0372] 95. The computer-readable medium of clause 94, wherein moving the position of the sample in the first direction comprises constantly moving the position of the sample at a first speed.

[0373] 96. A computer-readable medium according to any of clauses 94 and 95, wherein the scan line is positioned substantially perpendicular to the first direction.

[0374] 97. The computer-readable medium of any one of clauses 94 to 96, wherein the first scan line of the plurality of scan segments is positioned substantially parallel to the second scan line of the plurality of scan segments.

[0375] 98. The computer-readable medium of any of clauses 94 to 97, wherein the set of instructions is executable by the one or more processors to cause the controller to further perform:

[0376] The N charged particle beams are deflected to move the detection spots of the N charged particle beams from respective starting positions to respective ending positions in a second direction to follow the movement of the sample while scanning a set of scan lines.

[0377] 99. The computer-readable medium of clause 98, wherein the set of instructions is executable by the one or more processors to cause the controller to further perform:

[0378] The N charged particle beams are deflected to move the detection spots of the N charged particle beams from the respective end positions to the respective start positions in a third direction to reposition the detection spots to the respective start positions to prepare for scanning a next set of scan lines.

[0379] 100. A computer-readable medium as described in any of clauses 94 to 99, wherein the second direction is substantially opposite to the third direction.

[0380] 101. A computer-readable medium according to any of clauses 98 to 100, wherein:

[0381] Deflecting the N charged particle beams to move the detection spots of the N charged particle beams in the second direction comprises deflecting the N charged particle beams to move the detection spots of the N charged particle beams in the second direction at a second speed; and

[0382] Deflecting the N charged particle beams to move the detection spots of the N charged particle beams in the third direction includes deflecting the N charged particle beams to move the detection spots of the N charged particle beams in the third direction at a third speed.

[0383] 102. The computer-readable medium of clause 101, wherein the second speed is substantially the same as the third speed.

[0384] 103. A computer-readable medium as described in any of clauses 95 to 102, wherein the first speed is associated with a size of a scanning segment.

[0385] 104. The computer-readable medium of any one of clauses 95 to 102, wherein the first speed is determined based on a length of the scan line, the second speed, and the third speed.

[0386] 105. A method of scanning a sample by a multi-beam inspection system utilizing at least N charged particle beams, N being an integer greater than or equal to 2, the method comprising:

[0387] positioning the N charged particle beams so that each of the N charged particle beams can scan a different scan line in a first set of N adjacent scan lines;

[0388] scanning the first set of N adjacent scan lines of the sample by using the N charged particle beams while the sample moves in a first direction at a first speed;

[0389] repositioning the N charged particle beams relative to the start of the scanning of the first set of N adjacent scan lines so that each of the N charged particle beams scans a different scan line in a second set of adjacent scan lines; and

[0390] The second set of N adjacent scan lines of the sample are scanned by using the N charged particle beams while the sample moves in the first direction at the first speed.

[0391] 106. The method of clause 105, wherein the multi-beam inspection system utilizes N×M charged particle beams, and wherein M is an integer greater than or equal to 1.

[0392] 107. A method according to clause 106, wherein the N×M charged particle beams form an N×M charged particle beam array, wherein M is an integer greater than or equal to 2, and wherein the N charged particle beams are a first linear arrangement of the N charged particle beams of the N×M charged particle beam array.

[0393] 108. A method according to clause 107, wherein M is equal to N.

[0394] 109. The method of clause 107, wherein the second group of N charged particle beams is a second linear arrangement of N charged particle beams of the N×M array of charged particle beams, the method further comprising:

[0395] positioning the second linear arrangement of the N charged particle beams so that each beam of the second linear arrangement of the N charged particle beams can scan a different scan line in a third set of N adjacent scan lines;

[0396] scanning the third set of N adjacent scan lines of the sample by using the second set of N charged particle beams while the sample moves in the first direction at the first speed;

[0397] rearranging the second linear arrangement of the N charged particle beams relative to the start of the scanning of the third group of N adjacent scan lines so that each beam of the second linear arrangement of the N charged particle beams scans a different scan line in a fourth group of adjacent scan lines; and

[0398] The fourth group of N adjacent scan lines of the sample are scanned by using the second group of N charged particle beams while the sample moves in the first direction at the first speed.

[0399] 110. The method of clause 109, wherein the scan of the first group coincides with the scan of the third group, and wherein the scan of the second group coincides with the scan of the fourth group.

[0400] 111. The method of clause 110, wherein the scanning of the first group occurs substantially simultaneously with the scanning of the third group, and wherein the scanning of the second group occurs substantially simultaneously with the scanning of the fourth group.

[0401] 112. A method according to claim 105, wherein the positioning of the N charged particle beams occurs before the scanning of the first group, wherein the scanning of the first group occurs before the repositioning, wherein the repositioning occurs before the scanning of the second group, and wherein the sample moves continuously at substantially the first speed from the moment the scanning of the first group begins to the moment the scanning of the second group ends.

[0402] 113. The method according to clause 105, further comprising:

[0403] repositioning the N charged particle beams relative to the start of the scanning of the second set of N adjacent scan lines so that each of the N charged particle beams scans a different scan line in a third set of adjacent scan lines; and

[0404] When the sample moves in the first direction at the first speed, the third set of N adjacent scan lines of the sample is scanned by using the N charged particle beams,

[0405] wherein from the moment when the scanning of the first group starts to the moment when the scanning of the third group starts, the sample moves substantially continuously at the first speed,

[0406] wherein the first direction is substantially parallel to the y-axis of the sample, and movement relative to the sample in the first direction is movement in a direction of increasing y-coordinate values ​​of the y-axis,

[0407] wherein the scan line at the beginning of the first group is located at a y coordinate of the sample that is greater than the y coordinates of all other scan lines of the first group and the scan lines of the second and third groups,

[0408] wherein the scan line at the beginning of the third group is located at a y-coordinate of the sample that is less than the y-coordinates of all scan lines of the first and second groups and greater than the y-coordinates of all other scans of the third group, and

[0409] Wherein, from the moment when the scanning of the first group starts to the moment when the scanning of the third group starts, the travel distance of the sample relative to the fixed spot of the multi-beam inspection system is basically equal to the distance along the y-axis from the scanning line at the starting end of the first group to the scanning line at the starting end of the third group.

[0410] 114. The method according to clause 113,

[0411] wherein the positioning of the N charged particle beams occurs before the scanning of the first group, wherein the scanning of the first group occurs before the repositioning to enable the scanning of the second group, wherein the repositioning to enable the scanning of the second group occurs before the scanning of the second group, wherein the scanning of the second group occurs before the repositioning to enable the scanning of the third group, and wherein the repositioning to enable the scanning of the second group occurs before the scanning of the third group.

[0412] 115. A method for scanning a sample on a stage by a multi-beam inspection system, the multi-beam inspection system utilizing an N×M array of charged particle beams, N and M being integers greater than or equal to 2, the method comprising:

[0413] positioning the N×M array of charged particle beams so that each beam in the N×M array of charged particle beams at a first set of positions can scan a different scan section in a first set of N×M scan sections of the sample;

[0414] While the stage moves at a first speed in a first direction, scanning lines of at least a portion of the first group of N×M scanning sections of the sample by using the N×M array of charged particle beams;

[0415] repositioning the N×M array of charged particle beams relative to the start of the scan of the first set of N×M scan segments so that each beam in the N×M array of charged particle beams at a second set of positions can scan a different scan segment in a second set of N×M scan segments of the sample; and

[0416] While the stage moves in the first direction at the first speed, scanning lines of at least a portion of the second group of N×M scanning sections of the sample are scanned by using the N×M charged particle beam array.

[0417] 116. The method of clause 115, wherein the scan line is positioned substantially parallel to the first direction.

[0418] 117. The method according to any of clauses 115 and 116, further comprising:

[0419] While scanning the scan line, the N×M array of charged particle beams is deflected to accommodate the movement of the stage.

[0420] 118. A method according to any of clauses 115 to 117, wherein said repositioning of said N x M array of charged particle beams is performed while said stage is moving in said first direction at said first speed.

[0421] 119. The method according to clause 118, further comprising:

[0422] The N x M array of charged particle beams is deflected to accommodate the movement of the stage while repositioning the N x M array of charged particle beams.

[0423] 120. A method according to any of clauses 115 to 119, wherein corresponding positions in the first set of positions and the second set of positions of the N×M array of charged particle beams are substantially the same relative to a fixed point of the multi-beam inspection system.

[0424] 121. A method according to any of clauses 115 to 120, further comprising:

[0425] The N x M array of charged particle beams is rotated about an optical axis of the multi-beam inspection system.

[0426] 122. A method according to any of clauses 115 to 120, further comprising:

[0427] The stage is rotated about an optical axis of the multi-beam inspection system.

[0428] 123. A method according to any of clauses 115 to 122, wherein:

[0429] Scan segments in the first set of N×M scan segments of the sample partially overlap with scan segments in the second set of N×M scan segments of the sample to generate overlapping areas.

[0430] 124. A method according to clause 123, wherein the overlapping area is scanned multiple times.

[0431] 125. A method according to clause 124, wherein the overlapping area is scanned a first time when the first set of N×M scanning segments of the sample are scanned, and the overlapping area is scanned a second time when the second set of N×M scanning segments of the sample are scanned.

[0432] 126. The method according to clause 125, further comprising:

[0433] While scanning the first group of N×M scanning sections of the sample, acquiring first scanning data of the overlapping area;

[0434] While scanning the second group of N×M scanning sections of the sample, acquiring second scanning data of the overlapping area; and

[0435] The first and second scan data of the overlapping region are processed to produce a continuous image of the sample.

[0436] 127. A method according to any of clauses 115 to 126, further comprising:

[0437] The movement of the stage is controlled by a controller coupled to the stage.

[0438] 128. A method according to any one of clauses 115 to 127, wherein M is equal to N.

[0439] It should be understood that the multi-electron beam tool can use software to perform the above functions. For example, the multi-electron beam tool can control the electric sample stage to move the sample when scanning is performed. Similarly, the multi-electron beam tool can control and deflect the primary beam wave to move the detection spot along the scan line when the sample continues to move. In addition, the multi-electron beam tool can perform image processing to generate the beam spot image of the received secondary electron beam. The software can be stored on a non-transient computer readable medium. Common forms of non-transient media include, for example, floppy disks, flexible disks, hard disks, solid-state drives, tapes or any other magnetic data storage media, CD-ROMs, any other optical data storage media, any physical media with hole patterns, RAM, PROM and EPROM, cloud storage, FLASH-EPROM or any other flash memory, NVRAM, cache, registers, any other memory chip or cassette, and network versions of the above.

[0440] Although the disclosed embodiments have been explained with respect to their preferred embodiments, it should be understood that other modifications and variations may be made without departing from the spirit and scope of the appended claims.

Claims

1. A non-transitory computer readable medium storing a set of instructions executable by one or more processors of a multi-beam tool comprising a beam configuration system and a sample stage to cause the multi-beam tool to perform a method comprising the following steps: instructing the beam configuration system to rotate a charged particle beam array relative to a sample to be scanned by the multi-beam tool by a rotation angle determined based on the number of beams in a row of the charged particle beam array, The multi-beam tool generates a primary beam of charged particles and divides the primary beam into the array of charged particle beams.

2. The computer readable medium of claim 1 , wherein the array of charged particle beams is arranged around an optical axis of the multi-beam tool, wherein the set of instructions is executable by the one or more processors to cause the multi-beam tool to further perform: The sample stage is instructed to rotate the sample about the optical axis.

3. The computer readable medium of claim 1 , wherein the array of charged particle beams is arranged around an optical axis of the multi-beam tool, wherein the set of instructions is executable by the one or more processors to cause the multi-beam tool to further perform: The beam configuration system is instructed to rotate the charged particle beam array about the optical axis.

4. The computer readable medium of claim 1, wherein the set of instructions is executable by the one or more processors to cause the multi-beam tool to further perform: controlling the multi-beam tool to generate an image of a surface area of ​​the sample; and The beam configuration system is instructed to move the charged particle beam array across an area larger than the surface area captured in the image.

5. The computer readable medium of claim 4, wherein the set of instructions is executable by the one or more processors to cause the multi-beam tool to further perform: instructing the sample stage to move the sample along a first direction; and The beam configuration system is instructed to move the charged particle beam array to scan a set of scan lines covering a field of view along a second direction.

6. The computer-readable medium of claim 5, wherein the second direction is substantially perpendicular to the first direction relative to the sample.

7. The computer-readable medium of claim 5, wherein the second direction is substantially parallel to the first direction relative to the sample.

8. The computer readable medium of claim 5, wherein the set of scan lines are spaced apart a distance corresponding to a pixel size of the image generated by the multi-beam tool.

9. A multi-beam system comprising: a charged particle source configured to generate a primary beam of charged particles; The bundle configuration system is configured to: dividing the primary beam of charged particles into an array of beams; and deflecting the beam array to scan a set of scan lines along a first direction to cover a surface area of ​​a sample; as well as A sample stage for holding the sample, the sample stage being configured to move the sample at a constant speed along a second direction parallel to the first direction.

10. The multi-beam system of claim 9, wherein the beam configuration system is further configured to scan the set of scan lines in a set of scan segments, wherein each scan segment comprises a plurality of scan lines.

11. The multi-beam system of claim 10, wherein the number of the plurality of scan lines forming each scan segment is determined based on the number of beams in a row of the beam array.

12. The multi-beam system of claim 10, wherein a scan width of the scan lines in the scan section is predetermined but not limited by the beam array configuration.

13. The multi-beam system of claim 10, wherein each of the scanning segments is scanned in a raster scanning pattern.

14. The multi-beam system of claim 9, wherein the beam configuration system is further configured to rotate the beam array relative to the sample.

15. The multi-beam system of claim 9, wherein the sample stage is further configured to rotate the sample relative to the beam array.

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