Systems and methods for handling the impact of failing beams in multibeam inspection

Abstract

Systems and methods for handling the impact of failing beams in multibeam inspection. Methods include determining a capture rate that is based on a number of failing beams of the multibeam arrangement. Methods include determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using the multibeam arrangement by using multibeam arrangement information including positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other, the scanning strategy applying a shift between the positions of sequential portions that is a fraction of a dimension of the portion.

Description

SYSTEMS AND METHODS FOR HANDLING THE IMPACT OF FAILING BEAMS IN MULTIBEAM INSPECTIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of EP application 24182824.3 which was filed on 18 June 2024, and which is incorporated herein in its entirety by reference.FIELD

[0002] The description herein relates to the field of inspection and charged particle systems, and more particularly to methods for handling the impact of failing beams in multibeam inspection.BACKGROUND

[0003] In manufacturing processes of integrated circuits (ICs), unfinished or finished circuit components are inspected to ensure that they are manufactured according to design and are free of defects. An inspection system utilizing an optical microscope typically has resolution down to a few hundred nanometers; and the resolution is limited by the wavelength of light. As the physical sizes of IC components continue to reduce down to sub-100 or even sub-10 nanometers, inspection systems capable of higher resolution than those utilizing optical microscopes are needed.

[0004] A charged particle (e.g., electron) beam microscope, such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM), capable of resolution down to less than a nanometer, serves as a practicable tool for inspecting IC components having a feature size that is sub- 100 nanometers. With a SEM, electrons of a single primary electron beam, or electrons of a plurality of primary electron beams, can be focused on locations of interest of a wafer under inspection. The primary electrons interact with the wafer and may be backscattered or may cause the wafer to emit secondary electrons. The intensity of the electron beams comprising the backscattered electrons and the secondary electrons may vary based on the properties of the internal and external structures of the wafer, and thereby may indicate whether the wafer has defects.SUMMARY

[0005] Embodiments of the present disclosure provide systems, methods, and non-transitory computer readable mediums for handling the impact of failing beams in multibeam inspection. Embodiments may include inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method including determining a capture rate that is based on a number of failing beams of the multibeam arrangement.

[0006] Embodiments may include inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method including inputting a capture rate that is based on anumber of failing beams of the multibeam arrangement; and evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement.

[0007] Embodiments may include inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method including determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using the multibeam arrangement by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other, the scanning strategy applying a shift between the positions of sequential portions that is a fraction of a dimension of the portion.

[0008] Embodiments may include inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method including determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other, wherein the scanning strategy is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.

[0009] Embodiments may include inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method including determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other, and wherein the scanning strategy is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. l is a schematic diagram illustrating an example assessment apparatus, consistent with embodiments of the present disclosure.

[0011] FIG. 2 is a schematic diagram illustrating an example charged particle system, consistent with embodiments of the present disclosure.

[0012] FIG. 3 is a schematic diagram illustrating an example charged particle system, consistent with embodiments of the present disclosure.

[0013] FIG. 4 is a schematic diagram illustrating an example charged particle system, consistent with embodiments of the present disclosure.

[0014] FIG. 5 is a schematic diagram illustrating an example electron-optical system array, consistent with embodiments of the present disclosure.

[0015] FIG. 6 shows an exemplary beam map corresponding to a multibeam system, consistent with embodiments of the present disclosure.

[0016] FIG. 7 shows exemplary footprints of a column, consistent with embodiments of the present disclosure.

[0017] FIG. 8 shows exemplary scanning strategies in regions of one or more samples, consistent with embodiments of the present disclosure.

[0018] FIG. 9 shows exemplary scanning strategies in regions of one or more samples, consistent with embodiments of the present disclosure.

[0019] FIG. 10 shows exemplary scanning strategies in a region, consistent with embodiments of the present disclosure.DETAILED DESCRIPTION

[0020] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise represented. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the disclosure. Instead, they are merely examples of apparatuses and methods consistent with aspects related to the subject matter recited in the appended claims. For example, although some embodiments are described in the context of utilizing electron beams, the disclosure is not so limited. Other types of charged particle beams may be similarly applied. Furthermore, other imaging systems may be used, such as optical imaging, photodetection, x-ray detection, extreme ultraviolet inspection, deep ultraviolet inspection, or the like, in which they generate corresponding types of images.

[0021] Electronic devices are constructed of circuits formed on a piece of silicon called a substrate. Many circuits may be formed together on the same piece of silicon and are called integrated circuits or ICs. The size of these circuits has decreased dramatically so that many more of them can fit on the substrate. For example, an IC chip in a smart phone can be as small as a thumbnail and yet may include over 2 billion transistors, the size of each transistor being less than 1 / 1000th the size of a human hair.

[0022] Making these extremely small ICs is a complex, time-consuming, and expensive process, often involving hundreds of individual steps. Errors in even one step have the potential to result indefects in the finished IC rendering it useless. Thus, one goal of the manufacturing process is to avoid such defects to maximize the number of functional ICs made in the process, that is, to improve the overall yield of the process.

[0023] One component of improving yield is monitoring the chip making process to ensure that it is producing a sufficient number of functional ICs. One way to monitor the process is to inspect the chip circuit structures at various stages of their formation. Inspection may be carried out using a scanning electron microscope (SEM). A SEM can be used to image these extremely small structures, in effect, taking a “picture” of the structures of the wafer. The image can be used to determine if the structure was formed properly, and also if it was formed at the proper location. If the structure is defective, then the process can be adjusted so the defect is less likely to recur. Defects may be generated during various stages of semiconductor processing. For the reason stated above, it is important to find defects accurately and efficiently as early as possible.

[0024] The working principle of a SEM is similar to a camera. A camera takes a picture by receiving and recording brightness and colors of light reflected or emitted from people or objects. A SEM takes a “picture” by receiving and recording energies or quantities of electrons reflected or emitted from the structures. Before taking such a “picture,” an electron beam may be projected onto the structures, and when the electrons are reflected or emitted (“exiting”) from the structures, a detector of the SEM may receive and record the energies or quantities of those electrons to generate an image. To take such a “picture,” some SEMs use a single electron beam (referred to as a “single-beam SEM”), while some SEMs use multiple electron beams (referred to as a “multi-beam SEM”) to take multiple “pictures” of the wafer. By using multiple electron beams, the SEM may project more electron beams onto the structures for obtaining these multiple “pictures,” resulting in more electrons exiting from the structures. Accordingly, the detector may receive more exiting electrons simultaneously, and generate images of the structures of the wafer with a higher efficiency and a faster speed.

[0025] Typical systems require all beams in a system to work, such as in a single beam (e.g., when a failing beam means the tool will not work) and in some systems because so few beams are present all should work. In typical systems, the system is considered broken when one or more of the beams are failing.

[0026] Typical systems suffer from constraints. For example, a system with 100% of the beams working is not feasible for systems with many beams (e.g., due to yield issues). Moreover, systems with 100% guaranteed area coverage may result in throughput loss. Some typical systems may optimize throughput for cases where failing beams are near the edge of a beam grid. However, these systems may result in throughput loss when failing beams are near the center of a beam grid.

[0027] Additionally, it is not known a priori which beams are working and which are not working. Therefore, it cannot be assessed up front what part of the care area will be inspected and what part of the care area will not be inspected. In typical systems, the care areas which will be inspected may be known only after inspection based on image metrics (e.g., focus index).

[0028] The disclosed embodiments provide systems and methods that address some or all of these disadvantages by various solutions, which may be dependent on customers’ needs and different use cases (and not dependent on the performance of the tool).

[0029] In some disclosed embodiments, the fact that a system has missing beams may be accepted so long as the capture rate of the system meets a determined threshold. Missing or failing beams may occur and that data may be collected to generate images when a number of beams are failing.Accordingly, in such embodiments, not all beams are needed to work. That is, at least some disclosed embodiments take into consideration that some beams may fail, and use that information to assist with imaging.

[0030] In some disclosed embodiments, the fact that a system has a number of beams that are failing may be accepted so long as the failing beams are not systematically in the same location on a repeating structure. Accordingly, in some embodiments, in the next die, field (of dies), or wafer, the position of the footprint (the pattern of footprints or footprint scanning strategy) is shifted. The footprints in such a pattern of footprints may all be contiguous, but not overlapping.

[0031] In some disclosed embodiments, the full surface of the die (i.e., region of a repeating structure) should be scanned, requiring rescanning. Since there may be some failing beams, rescanning is applied to ensure that the scanning of the die meets requirements.

[0032] Any of the disclosed embodiments may be used, regardless of whether the capture rate is “good” (e.g., higher) or “bad” (e.g., lower).

[0033] Relative dimensions of components in drawings may be exaggerated for clarity. Within the following description of drawings, the same or like reference numbers refer to the same or like components or entities, and only the differences with respect to the individual embodiments are described.

[0034] As used herein, unless specifically stated otherwise, the term “or” encompasses all possible combinations, except where infeasible. For example, if it is stated that a component may include A or B, then, unless specifically stated otherwise or infeasible, the component may include A, or B, or A and B. As a second example, if it is stated that a component may include A, B, or C, then, unless specifically stated otherwise or infeasible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0035] Without limiting the scope of the present disclosure, some embodiments may be described in the context of providing detectors and detection methods in systems utilizing electron beams. However, the disclosure is not so limited. Other types of charged particle beams may be similarly applied. Furthermore, systems and methods for detection may be used in other imaging systems, such as optical imaging, photon detection, x-ray detection, ion detection, etc.

[0036] Reference is now made to FIG. 1, which is a schematic diagram illustrating an example assessment apparatus 100, e.g., an inspection apparatus, consistent with embodiments of the present disclosure. The assessment apparatus 100 of FIG. 1 includes a vacuum chamber 10, a load lockchamber 20, a charged particle-optical apparatus 40, an equipment front end module (EFEM) 30 and a controller 50. The charged particle device 41 may be within the vacuum chamber 10. The electron- optical apparatus 40 may comprise a charged particle device 41 (also known as an electron-optical device, an electron beam device or an electron beam device) and a motorized or actuated stage.

[0037] The EFEM 30 includes a first loading port 30a and a second loading port 30b. The EFEM 30 may include additional loading port(s). The first loading port 30a and second loading port 30b may, for example, receive substrate front opening unified pods (FOUPs) that contain substrates (e.g., semiconductor substrates or substrates made of other material(s)) or targets to be assessed (substrates, wafers, and samples are collectively referred to as “targets” hereafter). One or more robot arms (not shown) in EFEM 30 transport the targets to load lock chamber 20.

[0038] The load lock chamber 20 is used to remove the gas around a target. The load lock chamber 20 may be connected to a load lock vacuum pump system (not shown), which removes gas particles in the load lock chamber 20. The operation of the load lock vacuum pump system enables the load lock chamber to reach a first pressure below the atmospheric pressure. The main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas molecules in the main chamber 10 so that the pressure around the target reaches a second pressure lower than the first pressure. After reaching the second pressure, the target is transported to the charged particle device 41 by which it may be assessed. A charged particle device 41 may comprise either a single beam or a multi -beam charged particle-optical apparatus.

[0039] The controller 50 is electronically connected to the charged particle system 40. The controller 50 may be a processor (such as a computer) configured to control the charged particle beam assessment apparatus 100. A processor may be an electronic device capable of manipulating or processing information. For example, the processor may include any combination of any number of a central processing unit (or “CPU”), a graphics processing unit (or “GPU”), an optical processor, a programmable logic controllers, a microcontroller, a microprocessor, a digital signal processor, an intellectual property (IP) core, a Programmable Logic Array (PLA), a Programmable Array Logic (PAL), a Generic Array Logic (GAL), a Complex Programmable Logic Device (CPLD), a Field- Programmable Gate Array (FPGA), a System On Chip (SoC), an Application-Specific Integrated Circuit (ASIC), a neural processing unit (NPU), and any other type of circuit capable of data processing. The processor may also be a virtual processor that includes one or more processors distributed across multiple machines or devices coupled via a network.

[0040] The controller 50 may also include a processing circuitry configured to execute various signal and image processing functions. While the controller 50 is shown in FIG. 1 as being outside of the structure that includes the main chamber 10, the load lock chamber 20, and the EFEM 30, it is appreciated that the controller 50 may be part of the structure. The controller 50 may be located in one of the component elements of the charged particle beam assessment apparatus 100 or it may be distributed over at least two of the component elements. While the present disclosure providesexamples of main chamber 10 housing an electron beam assessment apparatus, it should be noted that aspects of the disclosure in their broadest sense are not limited to a chamber housing a charged particle-optical device 41. Rather, it is appreciated that the foregoing principles may also be applied to other apparatuses and other arrangements of apparatus that operate under the second pressure.

[0041] Reference is now made to FIG. 2, which is a schematic diagram illustrating an example charged particle system 40 including a multi-beam charged particle device 41 that is part of the example charged particle beam assessment apparatus 100 of FIG. 1, consistent with embodiments of the present disclosure. The multi -beam charged particle device 41 comprises an electron source 201 and a projection apparatus 230. The charged particle system 40 further comprises an actuated stage 209 and a sample holder 207. The sample holder may have a holding surface (not depicted) for supporting and holding the sample. Thus, the sample holder 207 may be configured to support the sample 208. Such a holding surface may be an electrostatic clamp operable to hold the sample during operation of the charged particle device 41 e.g. assessment such as measurement or inspection of at least part of the sample. The holding surface may be recessed into sample holder, for example a surface of the sample holder orientated to face the charged particle device 41. The electron source 201 and projection apparatus 230 may together be referred to as the charged particle device 41. The sample holder 207 is supported by actuated stage 209 so as to hold a sample 208 (e.g., a substrate or a mask) for assessment. The multi-beam charged particle device 41 further comprises a detector 240 (e.g., an electron detection device).

[0042] The electron source 201 may comprise a cathode (not shown) and an extractor or anode (not shown). During operation, the electron source 201 is configured to emit electrons as primary electrons from the cathode. The primary electrons are extracted or accelerated by the extractor or the anode to form a primary electron beam 202.

[0043] The projection apparatus 230 is configured to convert the primary electron beam 202 into a plurality of sub-beams 211, 212, 213 and to direct each sub-beam onto the sample 208. Although three sub-beams are illustrated for simplicity, there may be many tens, many hundreds or many thousands of sub-beams. The sub-beams may be referred to as beamlets, beams of the beam grid, etc.

[0044] The controller 50 may be connected to various parts of the charged particle beam assessment apparatus 100 of FIG. 1, such as the electron source 201, the detector 240, the projection apparatus 230, and the actuated stage 209. The controller 50 may perform various image and signal processing functions. The controller 50 may also generate various control signals to govern operations of the charged particle beam assessment apparatus, including the charged particle multi-beam apparatus.

[0045] The projection apparatus 230 may be configured to focus sub-beams 211, 212, and 213 onto a sample 208 for assessment and may form three probe spots 221, 222, and 223 on the surface of sample 208. The projection apparatus 230 may be configured to deflect the primary sub-beams 211, 212, and 213 to scan the probe spots 221, 222, and 223 across individual scanning areas in a section of the surface of the sample 208. Such scanning may be controlled by the controller 50 to cooperatewith a simultaneous scanning movement of the actuated stage 209. In response to incidence of the primary sub-beams 211, 212, and 213 on the probe spots 221, 222, and 223 on the sample 208, signal particles e.g., signal electrons are generated from the sample 208, which include secondary electrons and backscattered electrons. The secondary electrons typically have electron energy < 50 eV. Actual secondary electrons can have an energy of less than 5 eV, but anything beneath 50 eV is generally treated as a secondary electron. Backscattered electrons typically have electron energy between 0 eV and the landing energy of the primary sub-beams 211, 212, and 213. As electrons detected with an energy of less than 50 eV is generally treated as a secondary electron, a proportion of the actual backscatter electrons will be counted as secondary electrons.

[0046] The detector 240 is configured to detect signal particles such as secondary electrons or backscattered electrons and to generate corresponding signals, which are sent to a signal processing system 280, e.g., to construct images of the corresponding scanned areas of sample 208. The detector 240 may be incorporated into the projection apparatus 230.

[0047] The signal processing system 280, which may be part of the controller 50, may comprise a circuit (not shown) configured to process signals from the detector 240 so as to form an image. The signal processing system 280 could otherwise be referred to as a detection signal processing system. The signal processing system may be incorporated into a component of the multi-beam charged particle system 40 such as the detector 240 (as shown in FIG. 2). However, the signal processing system 280 may be incorporated into any components of the assessment apparatus 100 or multi-beam charged particle system 40, such as, as part of the projection apparatus 230 or the controller 50. The signal processing system 280 may include an image acquirer (not shown) and a storage device (not shown). For example, the signal processing system may comprise a processor, computer, server, mainframe host, terminals, personal computer, any kind of mobile computing devices, and the like, or a combination thereof. The image acquirer may comprise at least part of the processing function of the controller. Thus, the image acquirer may comprise at least one or more processors. The image acquirer may be communicatively coupled to the detector 240 permitting signal communication, such as an electrical conductor, optical fiber cable, portable storage media, IR, Bluetooth, internet, wireless network, wireless radio, among others, or a combination thereof. The image acquirer may receive a signal from the detector 240, may process the data comprised in the signal and may construct an image therefrom. The image acquirer may thus acquire images of the sample 208. The image acquirer may also perform various post-processing functions, such as generating contours, superimposing indicators on an acquired image, and the like. The image acquirer may be configured to perform adjustments of brightness and contrast, etc. of acquired images. The storage may be a storage medium such as a hard disk, flash drive, cloud storage, random access memory (RAM), other types of computer readable memory, and the like. The storage may be coupled with the image acquirer and may be used for saving scanned raw image data as original images, and post-processed images.

[0048] The signal processing system 280 may include measurement circuitry (e.g., analog-to-digital converters) to obtain a distribution of the detected secondary electrons. The electron distribution data, collected during a detection time window, may be used in combination with corresponding scan path data of each of primary sub-beams 211, 212, and 213 incident on the sample surface, to reconstruct images of the sample structures under assessment. The reconstructed images may be used to reveal various features of the internal or external structures of the sample 208. The reconstructed images may thereby be used to reveal any defects that may exist in the sample.

[0049] As mentioned, the controller 50 may control the actuated stage 209 to move sample 208 during assessment, e.g., inspection, of the sample 208. The controller 50 may enable the actuated stage 209 to move the sample 208 in a direction, preferably continuously, for example at a constant speed, at least during sample assessment. The controller 50 may control movement of the actuated stage 209 so that it changes the speed of the movement of the sample 208 dependent on various parameters. For example, the controller 50 may control the stage speed (including its direction) depending on the characteristics of the assessment steps of scanning process.

[0050] Known multi-beam systems, such as the charged particle system 40 and charged particle beam assessment apparatus 100 described above, are disclosed in US2020118784, US20200203116, US 2019 / 0259570 and US2019 / 0259564 all of which are hereby incorporated by reference in their entireties.

[0051] Components of a charged particle system 40, which may be used in some embodiments of the present disclosure are described below in relation to each and all of FIGs. 3 and 4, which are schematic diagrams of a charged particle system 40. The charged particle system 40 of the arrangements shown in these figures may correspond to the charged particle system 40 (which may also be referred to as an apparatus or a tool) mentioned above.

[0052] Considering the arrangement as shown in FIG. 4 the electron source 201 directs electrons toward an array of condenser lenses 231 (otherwise referred to as a condenser lens array). The electron source 201 is desirably a high brightness emitter arranged to operate within an optimized electron-optical performance range that is a compromise between brightness and total emission current (such a compromise may be considered to be a ‘good’ compromise). The electron source emits a source beam.

[0053] There may be many tens, many hundreds or many thousands, or even tens of thousands of condenser lenses 231. The condenser lenses 231 may comprise multi-electrode lenses and have a construction based on EP1602121A1, which is hereby incorporated by reference in particular to the disclosure of a lens array to split a source beam into a plurality of sub-beams. A most upbeam plate, which may be referred to as beam limiting aperture array, and which may be the most upbeam plate of the condenser lens array, may generate the plurality of beams. The array condenser lenses (which may comprise the beam limiting aperture array) may provide a lens for each sub-beam. The array of condenser lenses 231 may take the form of at least two plates, acting as electrodes, with an aperture ineach plate aligned with each other and corresponding to the location of a sub-beam. At least two of the plates are maintained during operation at different potentials to achieve the desired lensing effect.

[0054] In an arrangement the array of condenser lenses 231 is formed of three plate arrays in which charged particles have the same energy as they enter and leave each lens, which arrangement may be referred to as an Einzel lens. Thus, dispersion only occurs within the Einzel lens itself (between entry and exit electrodes of the lens), thereby limiting off-axis chromatic aberrations. When the thickness of the condenser lenses is low, e.g., a few mm, such aberrations have a small or negligible effect.

[0055] Each condenser lens 231 in the array directs electrons into a respective sub-beam 211, 212, 213, which is focused at a respective intermediate focus downbeam of the condenser lens array. The sub-beams diverge with respect to each other. In some embodiments, collimators such as deflectors 235 are provided at the intermediate focuses. The collimators are positioned in the sub-beam paths at, or at least around, the position of the corresponding intermediate points of focus. The collimators are positioned in or close to the sub-beam paths at the intermediate image plane of the associated subbeam. The collimators are configured to operate on the respective sub-beams 211, 212, 213. The collimators are configured to bend the respective sub-beam 211, 212, 213 by an amount effective to ensure that the principal ray (which may also be referred to as the beam axis) is incident on the sample 208 substantially normally (i.e., at substantially 90° to the nominal surface of the sample). The collimators (e.g., deflectors 235) may also be referred to as collimator deflectors. The deflectors 235 in effect collimate the paths of the sub-beams so that before the deflectors, the sub-beam paths with respect to each other are diverging. Downbeam of the collimators the sub-beam paths are substantially parallel with respect to each other, i.e., substantially collimated. Suitable collimators are deflectors disclosed in EP Application 20156253.5 filed on 7 February 2020, which is hereby incorporated by reference with respect to the application of the deflectors to a multi-beam array. In some embodiments of the arrangement, the collimator may comprise a macro collimator, instead of, or in addition to the deflectors 235. The macro-collimator may be electrostatic for example as two more planar plates with a single aperture.

[0056] Below (i.e., downbeam or further from source 201) the deflectors 235 there is a control lens array 250. The sub-beams 211, 212, 213 having passed through the deflectors 235 are substantially parallel on entry to the control lens array 250. The control lenses pre-focus the sub-beams (e.g., apply a focusing action to the sub-beams prior to the sub-beams reaching an objective lens array 241). The pre-focusing may reduce divergence of the sub-beams or increase a rate of convergence of the subbeams. The control lens array 250 and the objective lens array 241 operate together to provide a combined focal length. Combined operation without an intermediate focus may reduce the risk of aberrations. In some embodiments the control lenses of the control lens array may be considered to be part of the objective lenses of the objective lens array. The electrode plates of the control lens array may be considered electron-optically to be additional electrode plates of the objective lens array.

[0057] It is desirable to use the control lens array 250 to determine the landing energy. However, it is possible to use in addition the objective lens array 241 to control the landing energy. In such a case, a potential difference over the objective lens is changed when a different landing energy is selected.

[0058] The control lens array 250 comprises a plurality of control lenses. Each control lens comprises at least two electrodes (e.g., two or three electrodes) connected to respective potential sources. The control lens array 250 may comprise two or more (e.g., three) plate electrode arrays connected to respective potential sources. The control lens array 250 is associated with the objective lens array 241 (e.g., the two arrays are positioned close to each other or mechanically connected to each other or controlled together as a unit). Each control lens may be associated with a respective objective lens. The control lens array 250 is positioned upbeam of the objective lens array 241.

[0059] The control lens array 250 comprises a control lens for each sub-beam 211, 212, 213. A function of the control lens array 250 is to optimize the beam opening angle with respect to the demagnification of the beam or to control the beam energy delivered to the objective lens array 241 which directs the sub-beams 211, 212, 213 onto the sample 208. The objective lens array 241 may be positioned at or near the base of the charged particle device 41. The control lens array 250 is optional, but is preferred for optimizing a sub-beam upbeam of the objective lens array. In an arrangement the control lens array 250 may be considered to be part of the objective lens array. The plates of the control lens array may be considered to be additional plates of the objective lens array. Within an objective lens array meeting this definition the function of the control lens array may be a function of the objective lens array in addition to the functions of the objective lens array herein described.

[0060] For ease of illustration, lens arrays are depicted schematically herein by arrays of oval shapes (as shown in FIG. 4 and for that matter FIG. 3). Each oval shape represents one of the lenses in the lens array. The oval shape is used by convention to represent a lens, by analogy to the biconvex form often adopted in optical lenses. In the context of charged-particle arrangements such as those discussed herein, it will be understood however that lens arrays will typically operate electrostatically and so may not require any physical elements adopting a biconvex shape. Lens arrays may instead comprise multiple plates with apertures.

[0061] An array of scan deflectors 260 may be provided between the control lens array 250 and the array of objective lenses 241. The array of scan deflectors 260 comprises a scan deflector for each sub-beam 211, 212, 213. Each scan deflector is configured to deflect the respective sub-beam 211, 212, 213 in one or two directions so as to scan the sub beam across the sample 208 in one or two directions.

[0062] In the example of FIG. 3, the charged particle system 40 comprises a source 201, consistent with embodiments of the present disclosure. Features, functions, benefits, and advantages of the present disclosure described in reference to earlier embodiments apply to some embodiments referring to FIG. 3 unless statements are made to the contrary. The source 201 provides a beam of chargedparticles (e.g., electrons). The multi-beam focused on the sample 208 is derived from the beam provided by the source 201. Sub-beams may be derived from the beam, for example, using a beam limiter defining an array of beam-limiting apertures. For example, as shown in FIG. 3 in an example the charged particle device 41 comprises an upper beam limiter 252 that defines an array of beamlimiting apertures. The upper beam limiter 252 may comprise a plate (which may be a plate-like body) having a plurality of apertures.

[0063] The source 201 is desirably a high brightness thermal field emitter with a good compromise between brightness and total emission current. In the example shown, a collimator is provided upbeam of the objective lens array assembly. The collimator may comprise a macro collimator 270. The macro collimator 270 acts on the beam from the source 201 before the beam has been split into a multi-beam. The macro collimator 270 bends respective portions of the beam by an amount effective to ensure that a beam axis of each of the sub-beams derived from the beam is incident on the sample 208 substantially normally (i.e., at substantially 90° to the nominal surface of the sample 208). The macro collimator 270 applies a macroscopic collimation to the beam. The macro collimator 270 may thus act on all of the beam rather than comprising an array of collimator elements that are each configured to act on a different individual portion of the beam. The macro collimator 270 may comprise a magnetic lens or magnetic lens arrangement comprising a plurality of magnetic lens subunits (e.g., a plurality of electromagnets forming a multi-pole arrangement). Alternatively or additionally, the macro-collimator may be at least partially implemented electrostatically, for example wholly electrostatically. The macro-collimator may comprise an electrostatic lens or electrostatic lens arrangement comprising a plurality of electrostatic lens sub-units. The macro collimator 270 may use a combination of magnetic and electrostatic lenses. Desirably, the macro collimator 270 uses only electrostatic lenses.

[0064] In the example of FIG. 3 a macro scan deflector 265 is provided to cause sub-beams to be scanned over the sample 208. The macro scan deflector 265 deflects respective portions of the beam to cause the sub-beams to be scanned over the sample 208. In some embodiments, the macro scan deflector 265 comprises a macroscopic multi-pole deflector, for example with 8 poles or more. The macro-scan deflector may be electrostatic or magnetic. The deflection is such as to cause sub-beams derived from the beam to be scanned across the sample 208 in one direction (e.g., parallel to a single axis, such as an X axis) or in two directions (e.g., relative to two non-parallel axes, such as X and Y axes). The macro scan deflector 265 acts macroscopically on all of the beam rather than comprising an array of deflector elements that are each configured to act on a different individual portion of the beam. In the example shown, the macro scan deflector 265 is provided between the macro collimator 270 and the control lens array 250.

[0065] In some embodiments, for example variations of the arrangements shown in and described with reference to FIG. 3, both the macro scan deflector 265 and the scan-deflector array 260 are provided. In such an arrangement, the scanning of the sub-beams over the sample surface may beachieved by controlling the macro scan deflector and the scan-deflector array 260 together, preferably in synchronization. A variation may comprise both the macro collimator 270 and a collimator array, distributing the collimation action through the column. In a variation the scan deflector function may be achieved using a scan deflector array with a deflector for one or more sub-beams of the plurality of sub-beams. Such a scan deflector array may be between a control lens array 250 and an objective lens array 241. In a variation the collimating function may be achieved using a collimator array comprising collimating elements for operating on a different sub-beam of the plurality of beams. Such a collimating element may be a deflector. The collimator array may be associated with the control lens array, for example upbeam of a control lens array. In some embodiments, charged particle system 40 can comprise a plurality of charged particle devices each with such a collimator array and a scan deflector array. That is the functionality of each of the charged particle devices with the collimator array and the scan deflector array may correspond to the functionality of the charged particle device shown in and described with reference to FIG. 3, although the macro elements of the collimator and scan deflector are present as a collimator array and scan deflector array instead of macro components.

[0066] In some embodiments both a macro scan deflector and a scan-deflector array are provided. In such an arrangement, the scanning of the sub-beams over the sample surface may be achieved by controlling the macro scan deflector and the scan-deflector array together, preferably in synchronization.

[0067] The objective lens array assembly may further comprise a beam shaping limiter 242. The beam shaping limiter 242 defines an array of beam-limiting apertures. In an arrangement, the beam shaping limiter 242 is structurally integrated with an electrode of the objective lens array 241. Desirably, the beam shaping limiter 242 is positioned in a region of low electrostatic field strength. Each of the beam-limiting apertures is aligned with a corresponding objective lens in the objective lens array 241.

[0068] The electron-optical system of FIG. 3 further comprises a detector (not shown), for example detector 240 as described below in relation to FIG. 4 (as described further below), desirably the detector may be a detector array.

[0069] Components of a charged particle system 40 that may be used in the present disclosure are further described below in relation to FIG. 4, which is a schematic diagram of a charged particle system 40, consistent with embodiments of the present disclosure. The charged particle system 40 of FIG. 4 may correspond to the charged particle system 40 (which may also be referred to as an apparatus or a tool) mentioned above. Features of the earlier described embodiments are the same, unless stated to the contrary. Features, functions, benefits and advantages of the present disclosure described in reference to earlier embodiments apply to some embodiments here unless statements are made to the contrary. Similarly features, benefits function and advantages described with reference tosome embodiments described with reference to FIG. 4, unless stated to the contrary apply to the earlier mentioned embodiments.

[0070] The schematic diagram of an example charged particle device, as shown in FIG. 4 has an objective lens array assembly. The objective lens array assembly comprises the objective lens array 241. The objective lens array 241 comprises a plurality of objective lenses. Each objective lens comprises at least two electrodes (e.g., two or three electrodes) connected to respective potential sources. The objective lens array 241 may comprise two or more (e.g., three) plate electrode arrays connected to respective potential sources. Each objective lens formed by the plate electrode arrays may be a micro-lens operating on a different sub-beam or group of sub-beams in the multi-beam. Each plate defines a plurality of apertures (which may also be referred to as holes). The position of each aperture in a plate corresponds to the position of a corresponding aperture (or corresponding hole) in the other plate (or plates). The corresponding apertures define the objective lenses and each set of corresponding holes therefore operates in use on the same sub-beam or group of sub-beams in the multi-beam. Each objective lens projects a respective sub-beam of the multi-beam onto a sample 208.

[0071] The objective lens array assembly further comprises the control lens array 250. The control lenses pre-focus the sub-beams (e.g., apply a focusing action to the sub-beams prior to the sub-beams reaching the objective lens array 241). The pre-focusing may reduce divergence of the sub-beams or increase a rate of convergence of the sub-beams. The control lens array and the objective lens array operate together to provide a combined focal length. Combined operation without an intermediate focus may reduce the risk of aberrations. In some embodiments, the control lens array may be considered to be part of the objective lens array.

[0072] In the arrangement of FIG. 4, the objective lens array assembly comprises the scan-deflector array 260. The scan-deflector array 260 comprises a plurality of scan deflectors. Each scan deflector scans a respective sub-beam over, or across, the sample 208. The scan-deflector array 260 may thus comprise a scan deflector for each sub-beam. Each scan deflector may deflect rays in the sub-beam in one direction (e.g., parallel to a single axis, such as an X axis) or in two directions (e.g., relative to two non-parallel axes, such as X and Y axes). The deflection is such as to cause the sub-beam to be scanned across the sample 208 in the one or two directions (i.e., one dimensionally or two dimensionally). In some embodiments, the scanning deflectors described in EP2425444, which document is hereby incorporated by reference in its entirety specifically in relation to scan deflectors, may be used to implement the scan-deflector array 260. The scan-deflector array 260 is positioned between the objective lens array 241 and the control lens array 250. In the example shown, the scandeflector array 260 is provided instead of a macro scan deflector, such as an electrostatic scan deflector (not shown). A scan-deflector array 260 may be more spatially compact than a macro scan deflector.

[0073] The objective lens array assembly may comprise a detector 240. (Alternatively the detector may be comprised in the charged particle device 41 without having to be present in the objective lens array assembly). The detector 240 may comprise detector elements (e.g., sensor elements such as capture electrodes). The detector 240 may comprise any appropriate type of detector. For example, the detector elements may be charged based detector configured to detect charge detected with respect to time e.g., as current, scintillators or using semiconductor devices such as PIN elements. The detector 240 may be a direct current detector or an indirect current detector.

[0074] The detector 240 may be positioned between the objective lens array 241 and the sample 208. The detector 240 is configured to be the most downbeam feature of the electron-optical device, for example proximate the sample 208. The detector 240 may be very close to the sample 208, for example less than 5mm, preferably between 200 and 10 pm.

[0075] The detector 240 may be positioned in the device so as to face the sample 208. Alternatively or additionally, the detector 240 may be positioned elsewhere in the charged particle system 40 such that part of the charged particle device 41 that faces the sample 208 is other than, and thus is not, a detector; such as an electrode of the objective lens arrangement. In such an arrangement another element of the electron-optical device may face the sample during operation, for example an electrode plate of the objective lens. In all these arrangements there is a most downbeam element of the electron-optical system, such as detector 240, most proximate to the sample. The most downbeam surface of the most downbeam element may face the sample.

[0076] A bottom surface of the detector 240 (or a facing surface of the detector 240 that may face a sample 208 in use) may comprise a substrate on which are provided a plurality of detector elements. Each detector element may surround a beam aperture. The beam apertures may be formed by etching through the substrate. In the arrangement the beam apertures are in a hexagonal close packed array, or alternatively in a rectangular array. The detector elements may be arranged in a rectangular array or a hexagonal array.

[0077] In cross section of the detector, the detector elements form the bottommost, i.e., most close to the sample 208, surface of the detector 240. Between the detector elements and the main body of the substrate a logic layer may be provided. At least part of the signal processing system may be incorporated into the logic layer. A wiring layer is provided on the backside of, or within, the substrate and connected to the logic layer by through-substrate vias. The wiring layer can include control lines, data lines and power lines. A printed circuit board or other semiconductor chips may be provided on, for example connected to, the backside of detector 240.

[0078] The detector 240 may be implemented by integrating a CMOS chip detector into an electrode of the objective lens array 241, such as the bottom electrode of the objective lens array 241. Integration of a detector 240 into the objective lens array 241 or other component of the charged particle device 41 allows for the detection of electrons emitted in relation to multiple respective subbeams. The CMOS chip may embody the detector it may be orientated to face the sample. In someembodiments, detector elements to capture the secondary charged particles are formed in the surface metal layer of the CMOS device. The detector elements can be formed in other layers. Power and control signals of the CMOS may be connected to the CMOS by the through-silicon vias. A passive silicon substrate with holes shields the CMOS chip from high E-fields, for example providing robustness.

[0079] In order to maximize the detection efficiency, it is desirable to make the surface of the detector elements as large as possible, so that substantially all the area of the objective lens array 240 (excepting the apertures) is occupied by detector elements. Additionally or alternatively, each detector element has a diameter substantially equal to an array pitch (i.e., of the pitch of the apertures of the aperture array in the electrodes of the objective lens assembly 241). The diameter of each detector element may be less than approximately 600 pm, and preferably between approximately 50 pm and 500 pm. The pitch may be selected depending on the intended distance between the sample 208 and the detector 240. In some embodiments the outer shape of the detector element is a circle, but this can be made a square to maximize the detection area. The diameter of the through-substrate via can be minimized. A typical size of the electron beam is in the order of 5 to 15 pm.

[0080] In some embodiments, a single detector element surrounds each beam aperture. In some embodiments, a plurality of detector elements are provided around each beam aperture.

[0081] In some embodiments for example of any of the embodiments described with reference to and shown in FIG. 4, one or more aberration correctors are provided that reduce one or more aberrations in the sub-beams. The one or more aberration correctors may be provided in any of the embodiments, e.g., as part of the charged particle-optical device, or as part of an optical lens array assembly, or as part of an assessment system, or as part of an electron-optical arrangement. In some embodiments, each of at least a subset of the aberration correctors is positioned in, or directly adjacent to, a respective one of the intermediate foci (e.g., in or adjacent to the intermediate image plane). The subbeams have a smallest cross-sectional area in or near a focal plane such as the intermediate plane. This provides more space for aberration correctors than is available elsewhere, i.e., upbeam or downbeam of the intermediate plane (or than would be available in alternative arrangements that do not have an intermediate image plane). In some embodiments, aberration correctors positioned in, or directly adjacent to, the intermediate foci (or intermediate image plane) comprise correctors to correct for the source 201 appearing to be at different positions for different beams. Correctors can be used to correct macroscopic aberrations resulting from the source that prevent a good alignment between each sub-beam and a corresponding objective lens. In some embodiments, aberration correctors are integrated with, or directly adjacent to, the objective lens array 241. In some embodiments, these aberration correctors reduce one or more of the following: field curvature; focus error; and astigmatism. The aberration correctors may be CMOS based individual programmable deflectors as disclosed in EP2702595A1 or an array of multipole deflectors as disclosed EP2715768A2, of which the descriptions of the beamlet manipulators in both documents are hereby incorporated by reference.

[0082] Additionally or alternatively, one or more scanning deflectors (not shown) may be integrated with, or directly adjacent to, the objective lens array 241 for scanning the sub-beams 211, 212, 213 over the sample 208. In some embodiments, the scanning deflectors described in US 2010 / 0276606, which document is hereby incorporated by reference in its entirety, may be used.

[0083] In some embodiments, as exemplified in FIG. 5, an electron-optical system array 500 is provided, consistent with embodiments of the present disclosure. The array 500 may comprise a plurality of any of the electron-optical systems described herein. Each of the electron-optical systems focuses respective multi-beams simultaneously onto different regions of the same sample. Each region, in this context, may thus correspond to a portion or part of the surface of a sample. Each electron-optical system may form sub-beams from a beam of charged particles from a different respective source 201. Each respective source 201 may be one source in a plurality of sources 201. At least a subset of the plurality of sources 201 may be provided as a source array. The source array may comprise a plurality of sources 201 provided on a common substrate. The focusing of plural multi-beams simultaneously onto different regions of the same sample allows an increased area of the sample 208 to be processed (e.g., assessed) simultaneously. The electron-optical systems in the array 500 may be arranged adjacent to each other so as to project the respective multibeams onto adjacent regions of the sample 208. Any number of electron-optical systems may be used in the array 500. Preferably, the number of electron-optical systems is in the range of from 9 to 200. In some embodiments, the electron-optical systems are arranged in a rectangular array or in a hexagonal array. In other embodiments, the electron-optical systems are provided in an irregular array or in a regular array having a geometry other than rectangular or hexagonal. Each electron- optical system in the array 500 may be configured in any of the ways described herein when referring to a single electron-optical system, for example as described above. Details of such an arrangement is described in EPA 20184161.6 filed 6 Jul. 2020 which, with respect to how the objective lens is incorporated and adapted for use in the multi-column arrangement is hereby incorporated by reference. In the example of FIG. 5, each of the electron-optical systems comprises both a scandeflector array 260 and a collimator element array 271. The scan-deflector array 260 and collimator element array 271 are particularly well suited to incorporation into an electron-optical system array 500 because of their spatial compactness, which facilitates positioning of the electron-optical systems close to each other.

[0084] Reference is now made to FIG. 6, an exemplary beam map 600 corresponding to a multibeam system (e.g., example assessment apparatus 100 of FIG. 1, electron-optical apparatus 40 of FIGs. 1-3, charged particle device 41 of FIGs. 1, 2, and 4, electron-optical system array 500 of FIG. 5, etc.), consistent with embodiments of the present disclosure. In some embodiments, a multi-beam system may generate beam map 600. Beam map 600 may show an array 610 corresponding to a plurality of charged particle beams (e.g., plurality of sub-beams 211, 212, 213 of FIGs. 2, 3, 4, etc.) of a multi-beam system. For example, array 610 may show a layout of a plurality of charged particlebeams that are provided to a sample (e.g., sample 208 of FIGs. 2, 3, 4, 5, etc.) of the multi-beam system. In some embodiments, array 610 may include at least one functional charged particle beam 612 and at least one failing charged particle beam 614 or 616.

[0085] For example, functional charged particle beam 612 may correspond to a working charged particle beam that properly scans an area of the sample and failed charged particle beams 614 and 616 may correspond to a failing charged particle beam that does not properly scan (e.g., does not scan) an area of the sample.

[0086] As exemplified in FIG. 7, a footprint 732 (e.g., corresponding to scanning strategy of array 610 of FIG. 6) of the column may be defined as the smallest bounding box on the sample surface that surrounds all of the sub-beam processed areas, consistent with embodiments of the present disclosure. Thus, the footprint 732 has an outline or a boundary which corresponds to (e.g., is the same as) an outline of the smallest bounding box on the sample surface that surrounds all of the sub-beam processed areas. The sub-beam processed areas surrounded by the smallest bounding box are the subbeam processed areas formed at a single position (which may be referred to as a single nominal processing position) of the sample between leap displacements. The single position may correspond to a single position of the actuated stage 209. The single position may correspond to a single performance of the scanning of the multi-beam in the successive steps (e.g., for one position of the actuated stage 209). The footprint 732 of the column may thus be defined to have an outline that corresponds to the outline of the smallest bounding box on the sample surface that surrounds all of the sub-beam processed areas of a single performance. The size and shape of the footprint of the column may be defined by the size and shape of the multi-beam output surface of the column (e.g., a portion of the objective lens array closest to the sample 208). In some embodiments, the distance of displacement of the sample 208 (indicated schematically by the arrow 734 leading from the center 730 of one footprint 732 to the center 730 of another footprint 732) is substantially equal to or greater than a dimension 735 of the footprint parallel to the direction of the movement.

[0087] FIG. 8 shows a scanning strategy in a region 810A (e.g., a field or a die) of a sample and a scanning strategy in a region 810B (e.g., a field or a die) of a sample, consistent with embodiments of the present disclosure. Similar to footprint 732 of FIG. 7, footprints 81 A, 82A, and 83A of the column may be defined by the size and shape of the multibeam output surface of the column.Footprints 81 A, 82A, and 83A may each correspond to a portion of a sample surface in region 810A that is scanned according to a scanning strategy. Similarly, footprints 8 IB, 82B, and 83B of the column may be defined by the size and shape of the multibeam output surface of the column. Footprints 8 IB, 82B, and 83B may each correspond to a portion of a sample surface in region 810B that is scanned according to a scanning strategy.

[0088] The portions on the sample surface are scanned by shifting (i.e., stepping) the sample and field of view of the multibeam arrangement (e.g., beam grid, array 610 of FIG. 6, etc.) relative to each of a whole number of dimensions of the portion. For example, the scanning strategy may scan thesample surface in the order of footprint 81A to footprint 82A to footprint 83 A. It is understood that this order of scanning is an example and that any order of footprints could be used in a scanning strategy. The portions should tesselate as shown in FIG. 8.

[0089] In some embodiments, scanning a sample surface may include using a scanning strategy to scan region 810A and region 81 OB. For example, the same beams of a multibeam arrangement may scan the same parts (e.g., corresponding portions) of different regions (e.g., region 810A and region 81 OB). In some embodiments, scanning may occur to corresponding parts of the different regions before further parts of the region are scanned so that the information scanned from one portion is comparable with the information scanned from the other corresponding portion from the other region. For example, scanning may occur in the order of the following footprints: 81A, 81B, 82A, 82B, 83A, 83B, where the portion of footprint 81A in region 810A corresponds to the portion of footprint 81B in region 810B, the portion of footprint 82A in region 810A corresponds to the portion of footprint 82B in region 810B, and the portion of footprint 83A in region 810A corresponds to the portion of footprint 83B in region 810B.

[0090] In some embodiments, scanning may occur in all of one region before scanning occurs in another region. For example, portions of region 810A may be scanned before portions of region 810B are scanned. For example, scanning may occur in the order of the following footprints: 81A, 82A, 83 A and then 8 IB, 82B, 83B.

[0091] It is understood that the scanning strategies described above are examples and that different scanning strategies (e.g., different orders of footprints) may be used. For example, scanning may occur in the order of footprints 81A, 81B, 82A, 82B, 83A, 83B; footprints 81A, 81B, 82B, 82A, 83A, 83B; etc.

[0092] In some embodiments, a method of inspection of a sample using a multibeam arrangement (e.g., a beam grid, array 610 of FIG. 6, etc.) of a plurality of charged particle beams, may include determining a capture rate that is based on at least beam grid information that comprises a number of failing beams of the multibeam arrangement.

[0093] Capture rate is related to failing beams in a tool. Capture rate is based on the fraction of the actual defects that the tool (e.g., electron-optical apparatus 40 of FIGs. 1-3, charged particle device 41 of FIGs. 1, 2, and 4, electron-optical system array 500 of FIG. 5, etc.) is able to detect. Capture rate is mainly affected by the signal-to-noise ratio of the images. Capture rate is also affected by failing beams that cannot capture defects (e.g., failing beams contribute to a decrease in capture rate, the capture rate is related to a fraction of the plurality of charged particle beams that are non-failing charged particle beams). Capture rate is based on the result of how the tool is used (e.g., capture rate is affected by the chosen pixel size, chosen averaging condition, defect size, resolution, specifics of the wafer to be inspected, and failing beams). The missed area of a sample (e.g., as a fraction of the total inspected area), or the missed capture rate, may be calculated as: The number of failing beams divided by the total number of beams. In some embodiments, the capture rate can involve a ratio offailing beams and the total number of beams or can involve a ratio of non-failing beams and the total number of beams.

[0094] In some embodiments, the method of inspection may include supplying the number of failing beams for determining the capture rate. In some embodiments, determining the capture rate may include determining the number of failing beams. In some embodiments, the capture rate is related to a fraction of the plurality of charged particle beams that are working charged particle beams (e.g., working charged particle beams are non-failing beams). In some embodiments, the capture rate can involve a ratio of failing beams and the total number of beams or can involve a ratio of non-failing beams and the total number of beams. In some embodiments, identifying the failing beams is based on data from a detector (e.g., detector 240 of FIG. 2). In some embodiments, the capture rate is based on operation parameters of a detection signal. In some embodiments, the operation parameters include any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, the signal-to-noise ratio, charged particle beam current, or failing beams.

[0095] For example, if the current of the “worst” beam is below a certain threshold (e.g., the slowest beam determines the speed of the entire tool), the beam may be considered “failing.” The other operation parameters may affect the capture rate similarly. For example, if the resolution of a certain beam is above a certain threshold, the beam may be considered “failing.”

[0096] In some embodiments, the signal-to-noise ratio may depend on noise in detection signals at the detector.

[0097] In some embodiments, beam parameters for determining failing beams (i.e., beam properties) comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.

[0098] In some embodiments, identifying the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams. In some embodiments, identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, image grey levels, noise (e.g., image noise), or signal-to- noise (e.g., image signal-to-noise). In some embodiments, the noise or the signal-to-noise do not have to be of the image, but would at least be of the set of data.

[0099] In some embodiments, inspection may include evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement. In some embodiments, inspection of a sample using a multibeam arrangement of a plurality of charged particle beams includes inputting a capture rate that is based on a number of failing beams of the multibeam arrangement and evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement. For example, if the capture rate is below a certain threshold, scanning of the portion of the sample will not occur. In some embodiments, capture rate is based on a number of non-failing beams (e.g., the capture rate may be based on a ratio of failingbeams and the total number of beams or can involve a ratio of non-failing beams and the total number of beams).

[0100] In some embodiments, the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample. For example, the portion of the sample may correspond to a footprint (e.g., footprints 81 A, 82A, 83A, 81B, 82B, 83B, etc. of FIG. 8) of a scanning strategy.

[0101] In some embodiments, data comprises a data set corresponding to the data from scanning the sample surface at the portion. In some embodiments, the data comprises multiple data sets derived from different scanning of different portions of the sample surface.

[0102] In some embodiments, when evaluating the capture rate against the threshold determines that the capture rate satisfies the threshold (e.g., when the capture rate meets the threshold), inspection includes scanning the portion of the sample using the plurality of charged particle beams. In some embodiments, inspection may include generating data for determining presence of defects on the sample based on data from the scanning (e.g., scanning of one or more portions), such as a data set of the portion.

[0103] In some embodiments, when evaluating the capture rate against the threshold determines that the capture rate is under the threshold (e.g., when the capture rate does not satisfy or does not meet the threshold), inspection includes ending scanning. For example, inspection may include scanning the sample when the capture rate satisfies the threshold, evaluating the capture rate against the threshold again, and ending scanning when the capture rate does not satisfy or meet the threshold.

[0104] In some embodiments, inspection may include filtering out data derived from one or more detection signals corresponding to the failing beams. In some embodiments, the filtering occurs prior to generation of the data set or after the generation of the data set and may include removing data from the data set that corresponds to a failing beam. For example, data containing nuisances (e.g., false positives) may be removed from the data set.

[0105] In some embodiments, the plurality of charged particle beams of the multibeam arrangement define a beam grid (e.g., corresponding to array 610 of FIG. 6). In some embodiments, different beams of the multibeam arrangement are assigned to a beam area of each portion of the sample, wherein a beam area of the respective portion is assigned to a respective beam of the multibeam arrangement. In some embodiments, the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample when scanning a portion, for example between stepping between portions. In some embodiments, stepping between portions may be described as stepping between a dimension of a scanned portion (e.g., a beam grid footprint) or a dimension of the field of view or either.

[0106] In some embodiments, the method may include generating data for determining presence of defects on the sample based on data from the scanning, for example of the portion such as a data set. In some embodiments, the method may include filtering out data derived from one or more detection signals corresponding to the failing beams, where the filtering occurs prior to generation of the dataset, or after the generation of the data set and may include removing data from the data set that corresponds to a failing beam. In some embodiments, the data comprises a data set corresponding to the data from scanning the sample surface at the portion. In some embodiments, the data comprises multiple data sets derived from different scanning of different portions of the sample surface.

[0107] In some embodiments, the method includes supplementing the generated data with data corresponding to scanning after the shift, generating a data file, or combining data for scanned parts of a region by combining the datasets from different portions within the region.

[0108] In some embodiments, the multibeam arrangement information comprises the capture rate that is related to a fraction of the plurality of charged particle beams that are working charged particle beams. In some embodiments, the capture rate is based on operation parameters of a detection signal. In some embodiments, the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, the signal-to-noise ratio, charged particle beam current, or failing beams. In some embodiments, the signal-to-noise ratio may depend on detection signals, at the detector.

[0109] In some embodiments, beam parameters for determining failing beams (i.e., beam properties) comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.

[0110] In some embodiments, the method may include identifying the failing beams based on data from a detector. In some embodiments, the identifying of the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams. In some embodiments, identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, or image grey levels.

[0111] In some embodiments, the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample. In some embodiments, different beams of the multibeam arrangement are assigned a beam area of each portion of the sample.

[0112] FIG. 9 shows a scanning strategy in a region 910A (e.g., a field or a die) of a sample and a scanning strategy in a region 910B (e.g., a field or a die) of a sample, consistent with embodiments of the present disclosure. Similar to footprint 732 of FIG. 7, footprints 91A, 92A, and 93A of the column may be defined by the size and shape of the multibeam output surface of the column.Footprints 91 A, 92A, and 93A may each correspond to a portion of a sample surface in region 910A that is scanned according to a scanning strategy. Similarly, footprints 9 IB, 92B, and 93B of the column may be defined by the size and shape of the multibeam output surface of the column.Footprints 9 IB, 92B, and 93B may each correspond to a portion of a sample surface in region 910B that is scanned according to a scanning strategy.

[0113] The portions on the sample surface are scanned by shifting (i.e., stepping) the sample and field of view of the multibeam arrangement (e.g., beam grid, array 610 of FIG. 6, etc.) relative to each of a whole number of dimensions of the portion. The portions should tesselate as shown in FIG. 9.

[0114] In some embodiments, scanning a sample surface may include using a scanning strategy to scan region 910A, shift the scanning strategy (e.g., shift the pattern of footprints), and scan region 91 OB. For example, the beams of a multibeam arrangement may scan portions of region 910A, then shift positions in scanning strategy to scan portions of region 910B (e.g., scanning may not occur to corresponding parts of the different regions). For example, regions 910A and 910B may have a common pattern that is aligned with respect to the rectangles noting regions 910A and 910B, as noted by dashed lines 941 and 942 (e.g., the pattern within regions 910A and 910B are not aligned with respect to the scanning strategy footprints). It is understood that dashed lines 941 and 942 are used for illustrative purposes and are not part of any structure themselves. The position in scanning strategy may shift such that working (e.g., functional) beams of the multibeam arrangement may scan areas of region 910B that may not have been scanned by working beams in corresponding areas of region 910A. This scanning strategy is configured to reduce systematic omissions of beam areas of the sample surface due to failing beams of the multibeam arrangement. For example, by shifting the scanning strategy between regions, non-failing beams (e.g., beam 612 of FIG. 6) may scan areas in a region where corresponding areas in another region were not scanned by non-failing beams (e.g., functional beam 610 may scan areas in a region where corresponding areas in another region were scanned by failing beams 614 or 616 of FIG. 6).

[0115] In some embodiments, scanning may alternate between scanning one or more portions of region 910A and scanning one or more portions of region 910B. For example, scanning may occur in the order of the following footprints: 91A, 92A, 93A, shift scanning strategy, then 91B, 92B, 93B; 91A, shift scanning strategy, 91B, shift scanning strategy, 92A, shift scanning strategy, 92B, shift scanning strategy, 93A, shift scanning strategy, 93B; 91A, shift scanning strategy, 91B, 92B, shift scanning strategy, 92A, 93A, shift scanning strategy, 93B; etc. In some embodiments, die to die shifts between dies on different substrates may scan in the order of the following footprints: 91 A, 92 A, 93 A, shift scanning strategy, then 9 IB, 92B, 93B.

[0116] It is understood that the scanning strategies described above are examples and that different scanning strategies (e.g., different orders of footprints, different shifting of scanning strategies, such as different shifting directions, different shifting dimensions, different shifting distances, etc.) may be used.

[0117] In some embodiments, inspection of a sample using a multibeam arrangement of a plurality of charged particle beams (e.g., a beam grid, array 610 of FIG. 6, etc.) may include determining a scanning strategy for scanning a sample surface having at least two regions (e.g., regions 910A and 910B) having a common pattern using the multibeam arrangement by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein themultibeam arrangement has a field of view on the sample surface (e.g., footprints 91 A, 92 A, 93 A, 91B, 92B, 93B, etc.) that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other. In some embodiments, the scanning strategy includes applying a shift between the positions of sequential portions (e.g., sequential portions may be a portion from region 910A and a portion from region 91 OB) that is a fraction of a dimension of the portion (e.g., a fraction of a dimension of footprints 91A, 92A, 93 A, 91B, 92B, 93B, etc.). In some embodiments, the portions are the same size.

[0118] In some embodiments, the shift is between different regions of the sample surface. In some embodiments, the shift in position between the different regions of the at least two regions is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions. The shift is such that when the two positions are combined (e.g., the footprints of region 910A and the footprints of region 91 OB), each position is scanned by a good beam at least once.

[0119] In some embodiments, a method of inspection of a sample using a multibeam arrangement (e.g., beam grid) includes determining a scanning strategy for scanning a sample surface having at least two regions (e.g., regions 910A and 910B) having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface (e.g., footprints 91A, 92A, 93 A, 91B, 92B, 93B, etc.) that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other. In some embodiments, the scanning strategy is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.

[0120] In some embodiments, the shift is from a first portion (e.g., corresponding to any one of footprints 91 A, 92A, 93A, 91B, 92B, 93B, etc.) of a first region (e.g., region 910A or region 910B) to a second portion (e.g., corresponding to any one of footprints 9 IB, 92B, 93B, 91 A, 92A, 93 A) of a second region (e.g., regions 910B or 910A). In some embodiments, the regions are different dies (e.g., a first region is a first die and a second region is a second die; for example, a second die is consecutive to a first die; for example, the first region is a first die and the second region is a second die; for example, the second die is consecutive to the first die, etc.). In some embodiments, the regions are in different fields (e.g., field of view of a lithography scanner; field of view of a stepper; where a first region is a first field and the second region is a second field; for example, a second field is consecutive to a first field; for example, the first region is a first field and the second region is a second field; for example, the second field is consecutive to the first field; etc.).

[0121] In some embodiments, the first region and the second region are in a sequence and have one or more interleaving regions. In some embodiments, the first region is comprised in a surface of a first wafer and the second region is comprised in a surface of a second wafer, for example consecutive to the first wafer. In some embodiments, each of the at least two regions is a part of a die or a part of a field having a same pattern, optionally where different regions are: different parts of the same die or the same field having the same pattern or (b) of a different die or a different field having the same pattern.

[0122] In some embodiments, the sequential portions are in the same region (e.g., sequential portions may be a portion from region 910A to another portion from region 910A, sequential portions may be a portion from region 910B to another portion from region 910B, etc.). In some embodiments, a first region of the at least two regions and a second region of the at least two regions are on contiguous, non-overlapping areas of the sample surface (e.g., region 910A and region 910B may be on contiguous, non-overlapping areas of the sample surface).

[0123] In some embodiments, the shift comprises displacing the sample surface in one or more directions, for example in two different directions (e.g., in the X and Z directions) that are angled relative to each other. In some embodiments, the shift comprises rotating the sample surface in one or more directions.

[0124] In some embodiments, the positions of failing beams comprise a peripheral position away from a perimeter of the multibeam arrangement (e.g., failing beam 616 of FIG. 6). In some embodiments, the positions of failing beams comprise an inner position at or towards a center of the multibeam arrangement (e.g., failing beam 616 of FIG. 6). In some embodiments, the positions of failing beams comprise any positions within the multibeam arrangement (e.g., failing beams 614, 616 of FIG. 6).

[0125] In some embodiments, the scanning strategy minimizes a proportion of a sample surface that is systematically omitted from exposure (e.g., an assessment, where an assessment is any sort of assessment of a sample such as measurement (e.g., metrology), and inspection, where inspection is not an alternative to assessment, but a subset; etc.) by failing beams, where the sample surface is the at least two regions.

[0126] In some embodiments, the multibeam arrangement information is a map of one or more failing beams within the multibeam arrangement (e.g., beam map 600 of FIG. 6). The map is just one way of representing the information. The multibeam arrangement information could be a list of coordinates, which is not a map, but is used for relating different locations spaced relative to each other (e.g., without reference to other features).

[0127] In some embodiments, the at least two regions having the common pattern are a set of regions. In some embodiments, the method includes scanning the sample surface applying the scanning strategy.

[0128] In some embodiments, the method may include generating data for determining presence of defects on the sample based on data from the scanning, for example of the portion such as a data set. In some embodiments, the method may include filtering out data derived from one or more detection signals corresponding to the failing beams, where the filtering occurs prior to generation of the data set, or after the generation of the data set and may include removing data from the data set that corresponds to a failing beam. For example, data containing nuisances (e.g., false positives) may be removed from the data set. In some embodiments, the data comprises a data set corresponding to the data from scanning the sample surface at the portion. In some embodiments, the data comprises multiple data sets derived from different scanning of different portions of the sample surface.

[0129] In some embodiments, the method includes supplementing the generated data with data corresponding to scanning after the shift, generating a data file, or combining data for scanned parts of a region by combining the datasets from different portions within the region.

[0130] In some embodiments, the multibeam arrangement information comprises the capture rate that is related to a fraction of the plurality of charged particle beams that are working charged particle beams. In some embodiments, the capture rate is based on operation parameters of a detection signal. In some embodiments, the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, the signal-to-noise ratio, charged particle beam current, or failing beams. In some embodiments, the signal-to-noise ratio may depend on detection signals, at the detector.

[0131] In some embodiments, beam parameters for determining failing beams (i.e., beam properties) comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.

[0132] In some embodiments, the method may include identifying the failing beams based on data from a detector. In some embodiments, the identifying of the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams. In some embodiments, identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, or image grey levels.

[0133] In some embodiments, the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample. In some embodiments, different beams of the multibeam arrangement are assigned a beam area of each portion of the sample.

[0134] FIG. 10 shows a scanning strategy 1010A in a region 1010 (e.g., a field or a die) of a sample and a scanning strategy 1010B in a region 1010 (e.g., a field or a die) of the sample, where scanning strategy 1010B is a shift in scanning position from scanning strategy 1010A, consistent with embodiments of the present disclosure. For example, the shift is applied within the same field or region (although other similar regions exist on the sample). As discussed previously, the shift in scanning can be configured such that those portions on the sample corresponding to failing beams(e.g., failing beams 614 and 616 of FIG. 6) of the first scan can be scanned with a working beam (e.g., working beam 612 of FIG. 6) on the next scan or subsequent scans.

[0135] Similar to footprint 732 of FIG. 7, footprints 101 A and 102A of the column may be defined by the size and shape of the multibeam output surface of the column. Footprints 101A and 102A may each correspond to a portion of a sample surface in region 1010 that is scanned according to scanning strategy 1010A. While portion 101 A is shown to be partially in region 1010, it is understood that the described embodiments are exemplary and that embodiments of the present disclosure may be directed to any portion (e.g., partially within a region, entirely within a region, etc.). Similarly, footprints 10 IB and 102B of the column may be defined by the size and shape of the multibeam output surface of the column. Footprints 10 IB and 102B may each correspond to a portion of a sample surface in region 1010 that is scanned according to scanning strategy 1010B.

[0136] A first set of portions corresponding to footprints of scanning strategy 1010A have a step apart from each other (i.e., a shift having a whole number of dimensions of a portion associated with a footprint) and a second set of portions corresponding to footprints of scanning strategy 1010B are similar to the first set except shifted from the first set by a dimension that is a faction of a portion corresponding to a footprint.

[0137] The portions on the sample surface are scanned by shifting (i.e., stepping) the sample and field of view of the multibeam arrangement (e.g., beam grid, array 610 of FIG. 6, etc.) relative to each of a whole number of dimensions of the portion. The portions should tesselate as shown in FIG. 10.

[0138] In some embodiments, scanning a sample surface may include using scanning strategy 1010A to scan region 1010, shift the scanning strategy (e.g., shift the pattern of footprints) by a fraction of a portion to scanning strategy 1010B, and scan region 1010 (e.g., re-scan areas, portions, or parts of portions of region 1010). For example, the beams of a multibeam arrangement may scan portions of region 1010, then shift positions in scanning strategy by a fraction of a portion to scan portions of region 1010, where portions scanned using scanning strategy 1010A may overlap with some portions scanned using scanning strategy 1010B such that at least some portions of region 1010 are re-scanned. This scanning strategy is configured to reduce systematic omissions of beam areas of the sample surface due to failing beams of the multibeam arrangement and to increase scanning coverage of the sample surface to reduce omissions of beam areas due to failing beams of the multibeam arrangement.

[0139] In some embodiments, shifting between scanning strategies may occur between each sequential scanned portion of the sample surface (e.g., the portion associated with footprint 101A may be scanned, then shifting may occur between scanning strategy 1010A to scanning strategy 1010B by a fraction of a portion, then the portion associated with footprint 101B may be scanned, then shifting may occur between scanning strategy 1010B to scanning strategy 1010A by a fraction of a portion, then the portion associated with footprint 102A may be scanned, then shifting may occur between scanning strategy 1010A to scanning strategy 1010B by a fraction of a portion, then the portion associated with footprint 102B may be scanned, etc.). In some embodiments, shifting betweenscanning strategies may occur after scanning all portions of the sample surface according to the first scanning strategy (e.g., the portions associated with footprints 101A and 102A may be scanned, then shifting may occur between scanning strategy 1010A to scanning strategy 1010B by a fraction of a portion, then the portions associated with footprints 101B and 102B may be scanned, etc.).

[0140] In some embodiments, the order of scanning may occur as follows: footprint 101A, shift, footprint 101B, footprint 102B, shift, footprint 102A.

[0141] Similarly, the above described scanning strategies may be applied with die to die scanning strategies. For example, two dies may be scanned, then both dies may be re-scanned. In some embodiments, a first die may be scanned and then re-scanned, then a second die may be scanned and then re-scanned.

[0142] It is understood that the scanning strategies described above are examples and that different scanning strategies (e.g., different orders of footprints, different shifting of scanning strategies, such as different shifting directions, different shifting dimensions, different shifting distances, etc.) may be used. For example, footprints 101B or 102B of scanning strategy 1010B may be scanned before scanning footprints 101A or 102A of scanning strategy 1010A.

[0143] In some embodiments, methods of inspection of a sample using a multibeam arrangement of a plurality of charged particle beams (e.g., a beam grid) include determining a scanning strategy for scanning a sample surface having at least two regions (e.g., at least region 1010) having a common pattern using the multibeam arrangement by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface (e.g., footprints 101 A, 102A, 101B, 102B, etc.) and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other. In some embodiments, the scanning strategy includes applying a shift between the positions of sequential portions (e.g., sequential portions may be a portion from scanning strategy 1010A and a portion from scanning strategy 1010B) that is a fraction of a dimension of the portion (e.g., a fraction of a dimension of footprints 101A, 102A, 101B, 102B, etc.). In some embodiments, the portions are the same size.

[0144] In some embodiments, the sequential portions overlap, optionally the sequential portions are a first portion (e.g., portion associated with footprints 101A or 102A) and a second portion (e.g., portion associated with footprints 101B or 102B). In some embodiments, there are interleaving portions (e.g., corresponding to footprints) between the sequential portions. In some embodiments, the interleaving portions are on the same or other (e.g., different) regions. In some embodiments, the interleaving portions are on two other (e.g., different) regions.

[0145] In some embodiments, the scanning strategy is configured such that any location within the first portion (e.g., corresponding to footprints 101A, 102A, 101B, 102B, etc.) is scanned by at leastone working beam of the multibeam arrangement (e.g., due to rescanning the first portion with working / non-failing beams).

[0146] In some embodiments, a method of inspection of a sample using a multibeam arrangement includes determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion (e.g., footprints 101A, 102A, 101B, 102B, etc.) of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other. In some embodiments, the scanning strategy is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement (e.g., due to rescanning the first portion with working / non-failing beams).

[0147] In some embodiments, the portion before the shift and the portion after the shift overlap (e.g., the portions corresponding to footprints 101A and 101B overlap, the portions corresponding to footprints 102A and 102B overlap, etc.).

[0148] In some embodiments, the scanning strategy is a rescanning strategy in that different portions overlap on the sample surface (e.g., portions overlap, positions of the field of view of the beam grid overlap on the sample surface, etc.). In some embodiments, in the scanning strategy, different beams of the multibeam arrangement scan the same location of the at least two regions of the sample surface (e.g., beams of the multibeam arrangement may scan a location on the sample surface during scanning strategy 1010A and different beams of the multibeam arrangement may scan the same location during scanning strategy 1010B). In some embodiments, different beams of the multibeam arrangement scan the sample surface (e.g., at the same location of the sample surface) in different portions (e.g., beams of the multibeam arrangement may scan a location on a portion of the sample surface during a scanning strategy, then different beams may scan the same location in a different portion of a shifted scanning strategy; beams of the multibeam arrangement may scan a location on a portion corresponding to footprint 101 A or 102 A during scanning strategy 1010A and different beams of the multibeam arrangement may scan the same location in a different portion corresponding to footprint 102A or 102B during scanning strategy 1010B; etc.). In some embodiments, the shift in position between different portions (e.g., portions corresponding to footprints 101A and 101B; portions corresponding to footprints 102A and 102B; etc.) in a same region (e.g., region 1010) of the sample surface is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement. In some embodiments, the scanning strategy causes scanning an entire region (e.g., region 1010) of the sample, wherein the multibeam arrangement has at least one failing beam.

[0149] In some embodiments, the sequential portions are in the same region (e.g., sequential portions may be a portion associated with footprint 101 A and a portion associated with footprint 102A, a portion associated with footprint 101 A and a portion associated with footprint 101B, a portion associated with footprint 102A and a portion associated with footprint 102B, a portion associated with footprint 102A and a portion associated with 101B, etc.). In some embodiments, a first region of the at least two regions and a second region of the at least two regions are on contiguous, non-overlapping areas of the sample surface (e.g., region 1010 and another region may be on contiguous, nonoverlapping areas of the sample surface).

[0150] In some embodiments, the shift comprises displacing the sample surface in one or more directions, for example in two different directions (e.g., in the X and Z directions) that are angled relative to each other. In some embodiments, the shift comprises rotating the sample surface in one or more directions.

[0151] In some embodiments, the positions of failing beams comprise a peripheral position away from a perimeter of the multibeam arrangement (e.g., failing beam 616 of FIG. 6). In some embodiments, the positions of failing beams comprise an inner position at or towards a center of the multibeam arrangement (e.g., failing beam 616 of FIG. 6). In some embodiments, the positions of failing beams comprise any positions within the multibeam arrangement (e.g., failing beams 614, 616 of FIG. 6).

[0152] In some embodiments, the scanning strategy minimizes a proportion of a sample surface that is systematically omitted from exposure (e.g., an assessment, where an assessment is any sort of assessment of a sample such as measurement (e.g., metrology), and inspection, where inspection is not an alternative to assessment, but a subset; etc.) by failing beams, where the sample surface is one region.

[0153] In some embodiments, the multibeam arrangement information is a map of one or more failing beams within the multibeam arrangement (e.g., beam map 600 of FIG. 6). The map is just one way of representing the information. The multibeam arrangement information could be a list of coordinates, which is not a map, but is used for relating different locations spaced relative to each other (e.g., without reference to other features).

[0154] In some embodiments, the at least two regions having the common pattern are a set of regions. In some embodiments, the method includes scanning the sample surface applying the scanning strategy.

[0155] In some embodiments, the method may include generating data for determining presence of defects on the sample based on data from the scanning, for example of the portion such as a data set. In some embodiments, the method may include filtering out data derived from one or more detection signals corresponding to the failing beams, where the filtering occurs prior to generation of the data set, or after the generation of the data set and may include removing data from the data set that corresponds to a failing beam. For example, data corresponding to failing beams may not be useful orneeded during inspection, metrology, etc. In some embodiments, the data comprises a data set corresponding to the data from scanning the sample surface at the portion. In some embodiments, the data comprises multiple data sets derived from different scanning of different portions of the sample surface.

[0156] In some embodiments, the method includes supplementing the generated data with data corresponding to scanning after the shift, generating a data file, or combining data for scanned parts of a region by combining the datasets from different portions within the region.

[0157] In some embodiments, the multibeam arrangement information comprises the capture rate that is related to a fraction of the plurality of charged particle beams that are working charged particle beams. In some embodiments, the capture rate is based on operation parameters of a detection signal. In some embodiments, the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, the signal-to-noise ratio, charged particle beam current, or failing beams. In some embodiments, the signal-to-noise ratio may depend on detection signals, at the detector.

[0158] In some embodiments, beam parameters for determining failing beams (i.e., beam properties) comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.

[0159] In some embodiments, the method may include identifying the failing beams based on data from a detector. In some embodiments, the identifying of the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams. In some embodiments, identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, or image grey levels.

[0160] In some embodiments, the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample. In some embodiments, different beams of the multibeam arrangement are assigned a beam area of each portion of the sample.

[0161] A non-transitory computer readable medium may be provided that stores instructions for a processor of a controller (e.g., controller 50 of FIGs. 1, 4) for controlling the electron beam tool or other systems of other systems and servers, or components thereof, consistent with embodiments in the present disclosure. These instructions may allow the one or more processors to carry out image processing, data processing, beamlet scanning, graphical display, operations of a charged particle beam apparatus, or another imaging device, or the like for providing operations consistent with those described above for FIGs. 1-10. In some embodiments, the non-transitory computer readable medium may be provided that stores instructions for a processor to perform the steps of processes described with respect to FIGs. 1-10. Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a Compact Disc Read Only Memory (CD-ROM), any other optical data storagemedium, any physical medium with patterns of holes, a Random Access Memory (RAM), a Programmable Read Only Memory (PROM), and Erasable Programmable Read Only Memory (EPROM), a FLASH-EPROM or any other flash memory, Non-Volatile Random Access Memory (NVRAM), a cache, a register, any other memory chip or cartridge, and networked versions of the s me.

[0162] In this text reference is made to electron-optical plates in which one or more apertures are defined. Such a plate may be manufactured using processing suitable for manufacturing microelectromechanical systems (MEMS). Such a charged particle-optical component or device may be referred to as a MEMS. MEMS are miniaturized mechanical and electromechanical elements that are made using microfabrication techniques. In some embodiments, the charged particle system 40 comprises apertures, lenses and deflectors which may be formed as MEMS such as the condenser lens array, the control lens array, the objective lens array, the collimator array, scan deflector arrays, corrector arrays and even features of the detector array. Further such electron optical components such as the condenser lenses, objective lenses or detector may be formed as MEMS or CMOS devices.

[0163] One or more electric power sources may be provided as a power supply to the electron-optical element of each and every component and element of the different charged particle systems herein disclosed. Potentials may be applied to the different electrodes of the different electrostatic components. Current may be applied to the referenced magnetic components. Such components and elements include, for example: the macro-condenser lens, the source, the scan deflector, the detector, the electrodes of the control lenses of the control lens array 250, the objective lenses of the objective lens array 241, the elements of the collimator array, the lenses of the condenser lens array, the scan deflector array and corrector elements.

[0164] References to upper and lower, up and down, above and below, top and bottom etc. should be understood as referring to directions generally parallel to the (typically but not always vertical) upbeam and downbeam directions of charged particle beams for example relative to the path of the beams such as the path of the beam grid or impinging on the sample 208. Thus, references to upbeam and downbeam are intended to refer to directions in respect of the beam path independently of any present gravitational field.

[0165] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made as described without departing from the scope of the claims and clauses set out below.

[0166] The embodiments may further be described using the following clauses:1. A method of inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method comprising: determining a capture rate that is based on a number of failing beams of the multibeam arrangement.2. The method of clause 1, further comprising supplying the number of failing beams for determining the capture rate.3. The method of any of clauses 1-2, wherein determining the capture rate further comprises determining the number of failing beams.4. The method of any of clauses 1-3, wherein the capture rate is related to a fraction of the plurality of charged particle beams that are working charged particle beams.5. The method of any of clauses 1-4, wherein identifying the failing beams is based on data from a detector.6. The method of clause 5, wherein the capture rate is based on operation parameters of a detection signal.7. The method of clause 6, wherein the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, signal-to- noise ratio, charged particle beam current, or failing beams.8. The method of clause 7, wherein the signal-to-noise ratio may depend on noise at the detector.9. The method of any of clauses 7-8, wherein beam parameters for determining failing beams comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.10. The method of any of clauses 1-9, wherein identifying the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams.11. The method of clause 10, wherein identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, image grey levels, noise, or signal-to-noise.12. The method of any of clauses 1-11, further comprising evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement.13. A method of inspection of a sample using a multibeam arrangement and of a plurality of charged particle beams, the method comprising: inputting a capture rate that is based on a number of failing beams of the multibeam arrangement; and evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement.14. The method of clause 12 or 13, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.15. The method of clause 14, wherein data comprises a data set corresponding to the data from scanning the sample surface at the portion.16. The method of clause 15, wherein the data comprises multiple data sets derived from different scanning of different portions of the sample surface.17. The method of any of clauses 12-16, wherein, when the evaluating the capture rate against the threshold determines that the capture rate satisfies the threshold, scanning the portion of the sample using the plurality of charged particle beams.18. The method of clause 17, further comprising generating data for determining presence of defects on the sample based on data from the scanning, such as a data set of the portion.19. The method of any of clauses 13-18, wherein, when the evaluating the capture rate against the threshold determines that the capture rate is under the threshold, ending scanning.20. The method of any of clauses 18-19, further comprising filtering out data derived from one or more detection signals corresponding to the failing beams, optionally wherein the filtering is: (a) prior to generation of the data set, or (b) after the generation of the data set and may include removing data from the data set that corresponds to a failing beam.21. The method of any of clauses 13-20, wherein the plurality of charged particle beams of the multibeam arrangement define a beam grid.22. The method of any of clauses 1-21, wherein different beams of the multibeam arrangement are assigned to a beam area of each portion of the sample.23. The method of any of clauses 1-22, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.24. A method of inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using the multibeam arrangement by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other, the scanning strategy applying a shift between the positions of sequential portions that is a fraction of a dimension of the portion.25. The method of clause 24, wherein the shift is between different regions of the sample surface.26. The method of clause 25, wherein the shift in position between the different regions of the at least two regions is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.27. A method of inspection of a sample using a multibeam arrangement, the method comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by usingmultibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other, wherein the scanning strategy is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.28. The method of any of clauses 24-27, wherein the shift is from a first portion of a first region to a second portion of a second region.29. The method of clause 28, wherein the regions are different dies.30. The method of clause 28, wherein the regions are different fields.31. The method of clause 28, wherein the first region and the second region are in a sequence and have one or more interleaving regions.32. The method of any of clauses 28-30, wherein the first region is comprised in a surface of a first wafer and the second region is comprised in a surface of a second wafer, for example consecutive to the first wafer.33. The method of any of clauses 24-32, wherein each of the at least two regions is a part of a die or a part of a field having a same pattern, optionally wherein different regions are: (a) different parts of the same die or the same field having the same pattern or (b) of a different die or a different field having the same pattern.34. The method of clause 24, wherein the sequential portions overlap, optionally the sequential portions are a first portion and a second portion.35. The method of clause 33, wherein there are interleaving portions between the sequential portions.36. The method of clause 35, wherein the interleaving portions are on the same or other regions.37. The method of clauses 35 or 36, wherein the interleaving portions are on two regions.38. The method of any of clauses 34-37, wherein the scanning strategy is configured such that any location within the first portion is scanned by at least one working beam of the multibeam arrangement.39. A method of inspection of a sample using a multibeam arrangement, the method comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other, andwherein the scanning strategy is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement.40. The method of any of clauses 34-39, wherein the portion before the shift and the portion after the shift overlap.41. The method of any of clauses 34-40, wherein the scanning strategy is a rescanning strategy in that different portions overlap on the sample surface.42. The method of any of clauses 34-41, wherein in the scanning strategy different beams of the multibeam arrangement scan the same location of the at least two regions of the sample surface.43. The method of any of clauses 34-42, wherein different beams of the multibeam arrangement scan the sample surface for example at the same location of the sample surface in different portions.44. The method of any of clauses 34-43, wherein the shift in position between different portions in a same region of the sample surface is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement.45. The method of any one of clauses 34-44, wherein the scanning strategy causes scanning an entire region of the sample.46. The method of any of clauses 24-45, wherein the sequential portions are in the same region.47. The method of any of clauses 24-46, wherein a first region of the at least two regions and a second region of the at least two regions are on contiguous, non-overlapping areas of the sample surface.48. The method of any of clauses 24-47, wherein the shift comprises displacing the sample surface in one or more directions, for example in two different directions that are angled relative to each other.49. The method of any of clauses 24-48, wherein the shift comprises rotating the sample surface in one or more directions.50. The method of any of clauses 24-49, wherein the positions of failing beams comprise a peripheral position away from a perimeter of the multibeam arrangement.51. The method of any of clauses 24-50, wherein the positions of failing beams comprise an inner position at or towards a center of the multibeam arrangement.52. The method of any of clauses 24-51, wherein the positions of failing beams comprise any positions within the multibeam arrangement.53. The method of any of clauses 24-52, wherein the scanning strategy minimizes a proportion of a sample surface that is systematically omitted from exposure by failing beams.54. The method of any of clauses 24-53, wherein the multibeam arrangement information is a map of one or more failing beams within the multibeam arrangement.55. The method of any of clauses 24-54, wherein the at least two regions having the common pattern are a set of regions.56. The method of any of clauses 24-55, further comprising scanning the sample surface applying the scanning strategy.57. The method of any of clauses 12-23 or 56, further comprising generating data for determining presence of defects on the sample based on data from the scanning, for example of the portion such as a data set.58. The method of clause 57, further comprising filtering out data derived from one or more detection signals corresponding to the failing beams optionally wherein the filtering is: (a) prior to generation of the data set, or (b) after the generation of the data set and may include removing data from the data set that corresponds to a failing beam.59. The method of clauses 57-58, wherein the data comprises a data set corresponding to the data from scanning the sample surface at the portion.60. The method of clause 59, wherein the data comprises multiple data sets derived from different scanning of different portions of the sample surface.61. The method of any of clauses 57-60, further comprising supplementing the generated data with data corresponding to scanning after the shift for scanned parts of a region by combining the datasets from different portions within the region.62. The method of any of clauses 1-61, wherein the multibeam arrangement information comprises a capture rate which is related to a fraction of the plurality of charged particle beams that are working charged particle beams.63. The method of clause 62, wherein the capture rate is based on operation parameters of a detection signal.64. The method of clause 63, wherein the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, signal-to- noise ratio, charged particle beam current, or failing beams.65. The method of clause 64, wherein the signal-to-noise ratio may depend at a detector.66. The method of any of clauses 64-65, wherein beam parameters for determining failing beams comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.67. The method of any one of clauses 1-66, further comprising identifying the failing beams based on data from a detector.68. The method of clause 67, wherein the identifying of the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams.69. The method of clause 68, wherein identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, or image grey levels.70. The method of clause 69, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.71. The method of any of clauses 1-70, wherein different beams of the multibeam arrangement are assigned a beam area of each portion of the sample.72. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method comprising: determining a capture rate that is based on a number of failing beams of the multibeam arrangement.73. The non-transitory computer readable medium of clause 72, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform supplying the number of failing beams for determining the capture rate.74. The non-transitory computer readable medium of any of clauses 72-73, wherein determining the capture rate further comprises determining the number of failing beams.75. The non-transitory computer readable medium of any of clauses 72-74, wherein the capture rate is related to a fraction of the plurality of charged particle beams that are working charged particle beams.76. The non-transitory computer readable medium of any of clauses 72-75, wherein identifying the failing beams is based on data from a detector.77. The non-transitory computer readable medium of clause 76, wherein the capture rate is based on operation parameters of a detection signal.78. The non-transitory computer readable medium of clause 77, wherein the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, signal-to-noise ratio, charged particle beam current, or failing beams.79. The non-transitory computer readable medium of clause 78, wherein the signal-to-noise ratio may depend on noise at the detector.80. The non-transitory computer readable medium of any of clauses 78-79, wherein beam parameters for determining failing beams comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.81. The non-transitory computer readable medium of any of clauses 72-80, wherein identifying the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams.82. The non-transitory computer readable medium of clause 81, wherein identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, image grey levels, noise, or signal-to-noise.83. The non-transitory computer readable medium of any of clauses 72-82, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement.84. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of inspection of a sample using a multibeam arrangement and of a plurality of charged particle beams, the method comprising: inputting a capture rate that is based on a number of failing beams of the multibeam arrangement; and evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement.85. The non-transitory computer readable medium of clause 83 or 84, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.86. The non-transitory computer readable medium of clause 85, wherein data comprises a data set corresponding to the data from scanning the sample surface at the portion.87. The non-transitory computer readable medium of clause 86, wherein the data comprises multiple data sets derived from different scanning of different portions of the sample surface.88. The non-transitory computer readable medium of any of clauses 83-87, wherein, when the evaluating the capture rate against the threshold determines that the capture rate satisfies the threshold, scanning the portion of the sample using the plurality of charged particle beams.89. The non-transitory computer readable medium of clause 88, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform generating data for determining presence of defects on the sample based on data from the scanning, such as a data set of the portion.90. The non-transitory computer readable medium of any of clauses 84-89, wherein, when the evaluating the capture rate against the threshold determines that the capture rate is under the threshold, ending scanning.91. The non-transitory computer readable medium of any of clauses 89-90, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform filtering out data derived from one or more detection signals corresponding to the failing beams, optionally wherein the filtering is: (a) prior to generation of the data set, or (b) after the generation of the data set and may include removing data from the data set that corresponds to a failing beam.92. The non-transitory computer readable medium of any of clauses 84-91, wherein the plurality of charged particle beams of the multibeam arrangement define a beam grid.93. The non-transitory computer readable medium of any of clauses 82-92, wherein different beams of the multibeam arrangement are assigned to a beam area of each portion of the sample.94. The non-transitory computer readable medium of any of clauses 72-93, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.95. A non- transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using the multibeam arrangement by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other, the scanning strategy applying a shift between the positions of sequential portions that is a fraction of a dimension of the portion.96. The non-transitory computer readable medium of clause 95, wherein the shift is between different regions of the sample surface.97. The non-transitory computer readable medium of clause 96, wherein the shift in position between the different regions of the at least two regions is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.98. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of inspection of a sample using a multibeam arrangement, the method comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other, wherein the scanning strategy is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.99. The non-transitory computer readable medium of any of clauses 95-98, wherein the shift is from a first portion of a first region to a second portion of a second region.100. The non-transitory computer readable medium of clause 99, wherein the regions are different dies.101. The non-transitory computer readable medium of clause 99, wherein the regions are different fields.102. The non-transitory computer readable medium of clause 99, wherein the first region and the second region are in a sequence and have one or more interleaving regions.103. The non-transitory computer readable medium of any of clauses 99-101, wherein the first region is comprised in a surface of a first wafer and the second region is comprised in a surface of a second wafer, for example consecutive to the first wafer.104. The non-transitory computer readable medium of any of clauses 95-103, wherein each of the at least two regions is a part of a die or a part of a field having a same pattern, optionally wherein different regions are: (a) different parts of the same die or the same field having the same pattern or (b) of a different die or a different field having the same pattern.105. The non-transitory computer readable medium of clause 95, wherein the sequential portions overlap, optionally the sequential portions are a first portion and a second portion.106. The non-transitory computer readable medium of clause 104, wherein there are interleaving portions between the sequential portions.107. The non-transitory computer readable medium of clause 106, wherein the interleaving portions are on the same or other regions.108. The non-transitory computer readable medium of clauses 106 or 107, wherein the interleaving portions are on two regions.109. The non-transitory computer readable medium of any of clauses 105-108, wherein the scanning strategy is configured such that any location within the first portion is scanned by at least one working beam of the multibeam arrangement.110. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of inspection of a sample using a multibeam arrangement, the method comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other, and wherein the scanning strategy is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement.111. The non-transitory computer readable medium of any of clauses 105-110, wherein the portion before the shift and the portion after the shift overlap.112. The non-transitory computer readable medium of any of clauses 105-111, wherein the scanning strategy is a rescanning strategy in that different portions overlap on the sample surface.113. The non-transitory computer readable medium of any of clauses 105-112, wherein in the scanning strategy different beams of the multibeam arrangement scan the same location of the at least two regions of the sample surface.114. The non-transitory computer readable medium of any of clauses 105-113, wherein different beams of the multibeam arrangement scan the sample surface for example at the same location of the sample surface in different portions.115. The non-transitory computer readable medium of any of clauses 105-114, wherein the shift in position between different portions in a same region of the sample surface is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement.116. The non-transitory computer readable medium of any one of clauses 105-115, wherein the scanning strategy causes scanning an entire region of the sample.117. The non-transitory computer readable medium of any of clauses 95-116, wherein the sequential portions are in the same region.118. The non-transitory computer readable medium of any of clauses 95-117, wherein a first region of the at least two regions and a second region of the at least two regions are on contiguous, nonoverlapping areas of the sample surface.119. The non-transitory computer readable medium of any of clauses 95-118, wherein the shift comprises displacing the sample surface in one or more directions, for example in two different directions that are angled relative to each other.120. The non-transitory computer readable medium of any of clauses 95-119, wherein the shift comprises rotating the sample surface in one or more directions.121. The non-transitory computer readable medium of any of clauses 95-120, wherein the positions of failing beams comprise a peripheral position away from a perimeter of the multibeam arrangement.122. The non-transitory computer readable medium of any of clauses 95-121, wherein the positions of failing beams comprise an inner position at or towards a center of the multibeam arrangement.123. The non-transitory computer readable medium of any of clauses 95-122, wherein the positions of failing beams comprise any positions within the multibeam arrangement.124. The non-transitory computer readable medium of any of clauses 95-123, wherein the scanning strategy minimizes a proportion of a sample surface that is systematically omitted from exposure by failing beams.125. The non-transitory computer readable medium of any of clauses 95-124, wherein the multibeam arrangement information is a map of one or more failing beams within the multibeam arrangement.126. The non-transitory computer readable medium of any of clauses 95-125, wherein the at least two regions having the common pattern are a set of regions.127. The non-transitory computer readable medium of any of clauses 95-126, further comprising scanning the sample surface applying the scanning strategy.128. The non-transitory computer readable medium of any of clauses 83-94 or 127, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform generating data for determining presence of defects on the sample based on data from the scanning, for example of the portion such as a data set.129. The non-transitory computer readable medium of clause 128, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform filtering out data derived from one or more detection signals corresponding to the failing beams optionally wherein the filtering is: (a) prior to generation of the data set, or (b) after the generation of the data set and may include removing data from the data set that corresponds to a failing beam.130. The non-transitory computer readable medium of clauses 128-129, wherein the data comprises a data set corresponding to the data from scanning the sample surface at the portion.131. The non-transitory computer readable medium of clause 130, wherein the data comprises multiple data sets derived from different scanning of different portions of the sample surface.132. The non-transitory computer readable medium of any of clauses 128-131, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform supplementing the generated data with data corresponding to scanning after the shift for scanned parts of a region by combining the datasets from different portions within the region.133. The non-transitory computer readable medium of any of clauses 72-132, wherein the multibeam arrangement information comprises a capture rate which is related to a fraction of the plurality of charged particle beams that are working charged particle beams.134. The non-transitory computer readable medium of clause 133, wherein the capture rate is based on operation parameters of a detection signal.135. The non-transitory computer readable medium of clause 134, wherein the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, signal-to-noise ratio, charged particle beam current, or failing beams.136. The non-transitory computer readable medium of clause 135, wherein the signal-to-noise ratio may depend at a detector.137. The non-transitory computer readable medium of any of clauses 135-136, wherein beam parameters for determining failing beams comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.138. The non-transitory computer readable medium of any one of clauses 72-137, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform identifying the failing beams based on data from a detector.139. The non-transitory computer readable medium of clause 138, wherein the identifying of the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams.140. The non-transitory computer readable medium of clause 139, wherein identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, or image grey levels.141. The non-transitory computer readable medium of clause 140, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.142. The non-transitory computer readable medium of any of clauses 72-141, wherein different beams of the multibeam arrangement are assigned a beam area of each portion of the sample.143. A system to inspect of a sample using a multibeam arrangement of a plurality of charged particle beams, the system comprising: a memory storing a set of instructions; and one or more processors configured to execute the set of instructions to cause the system to perform operations comprising: determining a capture rate that is based on a number of failing beams of the multibeam arrangement.144. The system of clause 143, wherein the operations further comprise supplying the number of failing beams for determining the capture rate.145. The system of any of clauses 143-144, wherein determining the capture rate further comprises determining the number of failing beams.146. The system of any of clauses 143-145, wherein the capture rate is related to a fraction of the plurality of charged particle beams that are working charged particle beams.147. The system of any of clauses 143-146, wherein identifying the failing beams is based on data from a detector.148. The system of clause 147, wherein the capture rate is based on operation parameters of a detection signal.149. The system of clause 148, wherein the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, signal-to- noise ratio, charged particle beam current, or failing beams.150. The system of clause 149, wherein the signal-to-noise ratio may depend on noise at the detector.151. The system of any of clauses 149-150, wherein beam parameters for determining failing beams comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.152. The system of any of clauses 143-151, wherein identifying the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams.153. The system of clause 152, wherein identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, image grey levels, noise, or signal-to-noise.154. The system of any of clauses 143-153, wherein the operations further comprise evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement.155. A system to inspect a sample using a multibeam arrangement and of a plurality of charged particle beams, the system comprising: a memory storing a set of instructions; and one or more processors configured to execute the set of instructions to cause the system to perform operations comprising: inputting a capture rate that is based on a number of failing beams of the multibeam arrangement; and evaluating the capture rate against a threshold to determine whether to scan a portion of the sample with the multibeam arrangement.156. The system of clause 154 or 155, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.157. The system of clause 156, wherein data comprises a data set corresponding to the data from scanning the sample surface at the portion.158. The system of clause 157, wherein the data comprises multiple data sets derived from different scanning of different portions of the sample surface.159. The system of any of clauses 154-158, wherein, when the evaluating the capture rate against the threshold determines that the capture rate satisfies the threshold, scanning the portion of the sample using the plurality of charged particle beams.160. The system of clause 159, wherein the operations further comprise generating data for determining presence of defects on the sample based on data from the scanning, such as a data set of the portion.161. The system of any of clauses 155-160, wherein, when the evaluating the capture rate against the threshold determines that the capture rate is under the threshold, ending scanning.162. The system of any of clauses 160-161, wherein the operations further comprise filtering out data derived from one or more detection signals corresponding to the failing beams, optionally wherein thefiltering is: (a) prior to generation of the data set, or (b) after the generation of the data set and may include removing data from the data set that corresponds to a failing beam.163. The system of any of clauses 155-162, wherein the plurality of charged particle beams of the multibeam arrangement define a beam grid.164. The system of any of clauses 143-163, wherein different beams of the multibeam arrangement are assigned to a beam area of each portion of the sample.165. The system of any of clauses 143-164, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.166. A system to inspect a sample using a multibeam arrangement of a plurality of charged particle beams, the system comprising: a memory storing a set of instructions; and one or more processors configured to execute the set of instructions to cause the system to perform operations comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using the multibeam arrangement by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other, the scanning strategy applying a shift between the positions of sequential portions that is a fraction of a dimension of the portion.167. The system of clause 166, wherein the shift is between different regions of the sample surface.168. The system of clause 167, wherein the shift in position between the different regions of the at least two regions is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.169. A system to inspect a sample using a multibeam arrangement, the system comprising: a memory storing a set of instructions; and one or more processors configured to execute the set of instructions to cause the system to perform operations comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other,wherein the scanning strategy is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.170. The system of any of clauses 166-169, wherein the shift is from a first portion of a first region to a second portion of a second region.171. The system of clause 170, wherein the regions are different dies.172. The system of clause 170, wherein the regions are different fields.173. The system of clause 170, wherein the first region and the second region are in a sequence and have one or more interleaving regions.174. The system of any of clauses 170-172, wherein the first region is comprised in a surface of a first wafer and the second region is comprised in a surface of a second wafer, for example consecutive to the first wafer.175. The system of any of clauses 166-174, wherein each of the at least two regions is a part of a die or a part of a field having a same pattern, optionally wherein different regions are: (a) different parts of the same die or the same field having the same pattern or (b) of a different die or a different field having the same pattern.176. The system of clause 166, wherein the sequential portions overlap, optionally the sequential portions are a first portion and a second portion.177. The system of clause 175, wherein there are interleaving portions between the sequential portions.178. The system of clause 177, wherein the interleaving portions are on the same or other regions.179. The system of clauses 177 or 178, wherein the interleaving portions are on two regions.180. The system of any of clauses 176-179, wherein the scanning strategy is configured such that any location within the first portion is scanned by at least one working beam of the multibeam arrangement.181. A system to inspect a sample using a multibeam arrangement, the system comprising: a memory storing a set of instructions; and one or more processors configured to execute the set of instructions to cause the system to perform operations comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using a multibeam arrangement of charged particle beams by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the multibeam arrangement relative to each other, andwherein the scanning strategy is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement.182. The system of any of clauses 176-181, wherein the portion before the shift and the portion after the shift overlap.183. The system of any of clauses 176-182, wherein the scanning strategy is a rescanning strategy in that different portions overlap on the sample surface.184. The system of any of clauses 176-183, wherein in the scanning strategy different beams of the multibeam arrangement scan the same location of the at least two regions of the sample surface.185. The system of any of clauses 176-184, wherein different beams of the multibeam arrangement scan the sample surface for example at the same location of the sample surface in different portions.186. The system of any of clauses 176-185, wherein the shift in position between different portions in a same region of the sample surface is configured such that any location within the portion is scanned by at least one working beam of the multibeam arrangement.187. The system of any one of clauses 176-186, wherein the scanning strategy causes scanning an entire region of the sample.188. The system of any of clauses 166-187, wherein the sequential portions are in the same region.189. The system of any of clauses 166-188, wherein a first region of the at least two regions and a second region of the at least two regions are on contiguous, non-overlapping areas of the sample surface.190. The system of any of clauses 166-189, wherein the shift comprises displacing the sample surface in one or more directions, for example in two different directions that are angled relative to each other.191. The system of any of clauses 166-190, wherein the shift comprises rotating the sample surface in one or more directions.192. The system of any of clauses 166-191, wherein the positions of failing beams comprise a peripheral position away from a perimeter of the multibeam arrangement.193. The system of any of clauses 166-192, wherein the positions of failing beams comprise an inner position at or towards a center of the multibeam arrangement.194. The system of any of clauses 166-193, wherein the positions of failing beams comprise any positions within the multibeam arrangement.195. The system of any of clauses 166-194, wherein the scanning strategy minimizes a proportion of a sample surface that is systematically omitted from exposure by failing beams.196. The system of any of clauses 166-195, wherein the multibeam arrangement information is a map of one or more failing beams within the multibeam arrangement.197. The system of any of clauses 166-196, wherein the at least two regions having the common pattern are a set of regions.198. The system of any of clauses 166-197, wherein the operations further comprise scanning the sample surface applying the scanning strategy.199. The system of any of clauses 154-165 or 198, wherein the operations further comprise generating data for determining presence of defects on the sample based on data from the scanning, for example of the portion such as a data set.200. The system of clause 199, wherein the operations further comprise filtering out data derived from one or more detection signals corresponding to the failing beams optionally wherein the filtering is: (a) prior to generation of the data set, or (b) after the generation of the data set and may include removing data from the data set that corresponds to a failing beam.201. The system of clauses 199-200, wherein the data comprises a data set corresponding to the data from scanning the sample surface at the portion.202. The system of clause 201, wherein the data comprises multiple data sets derived from different scanning of different portions of the sample surface.203. The system of any of clauses 199-202, further comprising supplementing the generated data with data corresponding to scanning after the shift for scanned parts of a region by combining the datasets from different portions within the region.204. The system of any of clauses 143-203, wherein the multibeam arrangement information comprises a capture rate which is related to a fraction of the plurality of charged particle beams that are working charged particle beams.205. The system of clause 204, wherein the capture rate is based on operation parameters of a detection signal.206. The system of clause 205, wherein the operation parameters comprise any of chosen pixel size, chosen averaging condition, defect size, resolution, specifics of a wafer to be inspected, signal-to- noise ratio, charged particle beam current, or failing beams.207. The system of clause 206, wherein the signal-to-noise ratio may depend at a detector.208. The system of any of clauses 206-207, wherein beam parameters for determining failing beams comprise any of charged particle beam focus, charged particle beam resolution, or charged particle beam current.209. The system of any one of clauses 143-208, wherein the operations further comprise identifying the failing beams based on data from a detector.210. The system of clause 209, wherein the identifying of the failing beams is based on one or more sets of data, which may be rendered into images for identifying the failing beams.211. The system of clause 210, wherein identifying the failing beams is based on a parameter of the set of data, such as any measurable parameter of the images when the set of data is rendered, including any of image quality, image sharpness, image contrast, image intensity, or image grey levels.212. The system of clause 211, wherein the portion of the sample corresponds to a field of view of the plurality of charged particle beams on the sample.213. The system of any of clauses 143-212, wherein different beams of the multibeam arrangement are assigned a beam area of each portion of the sample.

[0167] It will be appreciated that the embodiments of the present disclosure are not limited to the exact construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

CLAIMS1. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method comprising: determining a capture rate that is based on a number of failing beams of the multibeam arrangement.

2. The non-transitory computer readable medium of claim 1, wherein the set of instructions that is executable by at least one processor of a computing device to cause the computing device to further perform supplying the number of failing beams for determining the capture rate.

3. The non-transitory computer readable medium of claim 1, wherein determining the capture rate further comprises determining the number of failing beams.

4. The non-transitory computer readable medium of claim 1, wherein the capture rate is related to a fraction of the plurality of charged particle beams that are working charged particle beams.

5. The non-transitory computer readable medium of claim 1, wherein identifying the failing beams is based on data from a detector.

6. The non-transitory computer readable medium of claim 5, wherein the capture rate is based on operation parameters of a detection signal.

7. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of inspection of a sample using a multibeam arrangement of a plurality of charged particle beams, the method comprising: determining a scanning strategy for scanning a sample surface having at least two regions having a common pattern using the multibeam arrangement by using multibeam arrangement information comprising positions of failing beams in the multibeam arrangement, wherein the multibeam arrangement has a field of view on the sample surface that is a portion of the sample surface and the scanning strategy determines the positions of different portions on the sample surface in the scanning strategy when stepping the sample and field of view of the beam grid relative to each other,the scanning strategy applying a shift between the positions of sequential portions that is a fraction of a dimension of the portion.

8. The non- transitory computer readable medium of claim 7, wherein the shift is between different regions of the sample surface.

9. The non-transitory computer readable medium of claim 8, wherein the shift in position between the different regions of the at least two regions is configured such that any location in the at least two regions is scanned by a working beam of the multibeam arrangement in at least one of region of the at least two regions.

10. The non-transitory computer readable medium of claim 7, wherein the shift is from a first portion of a first region to a second portion of a second region.

11. The non-transitory computer readable medium of claim 10, wherein the regions are different dies.

12. The non-transitory computer readable medium of claim 10, wherein the regions are different fields.

13. The non-transitory computer readable medium of claim 10, wherein the first region and the second region are in a sequence and have one or more interleaving regions.

14. The non-transitory computer readable medium of claim 10, wherein the first region is comprised in a surface of a first wafer and the second region is comprised in a surface of a second wafer, for example consecutive to the first wafer.

15. The non-transitory computer readable medium of claim 7, wherein each of the at least two regions is a part of a die or a part of a field having a same pattern, optionally wherein different regions are: (a) different parts of the same die or the same field having the same pattern or (b) of a different die or a different field having the same pattern.

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