Charged particle device and charged particle apparatus

Abstract

The present invention provides a charged particle device for projecting multiple beams of charged particles toward a sample. The device includes a plurality of sources configured to emit respective source beams of charged particles, comprising the plurality of charged particle beams, along respective paths of a beam grid toward the sample. The device further includes one or more elements having an array of apertures defined therein. The one or more elements each include a plurality of beam regions assigned to a respective source beam. The one or more elements are configured to operate on the charged particle beams within the beam grid of the respective source beam. Each element is separated from an adjacent element by a spacer, the spacer having at least one aperture positioned to correspond to the positions of at least two of the beam regions.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to European Patent Application No. 22215638.2, filed December 21, 2022, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE INVENTION

[0002] Embodiments provided herein generally relate to charged particle devices and charged particle apparatus comprising charged particle devices. [Background technology]

[0003]

[0003] When manufacturing semiconductor integrated circuit (IC) chips, unwanted pattern defects, due to, for example, optical effects and incidental particles, inevitably occur on the substrate (i.e., wafer) or mask during the manufacturing process, thereby reducing yield. Therefore, monitoring the extent of unwanted pattern defects is an important process in the manufacturing of IC chips. More generally, evaluation, e.g., inspection and / or measurement, of the surface of a substrate, or other object / material, is an important process during and / or after its manufacturing.

[0004]

[0004] Pattern evaluation systems using charged particle beams have been used to inspect objects, for example, to detect pattern defects and measure structural features on such objects. These tools typically use electron microscopy, using an electron optical system, for example, in a scanning electron microscope (SEM). In an exemplary electron optical system, such as an SEM, a primary electron beam of relatively high-energy electrons is directed toward a target with a final deceleration step so that it strikes a sample with a relatively low incident energy. The electron beam is focused onto the sample as a probe spot. Interaction between the material structure of the probe spot and the incident electrons from the electron beam causes electrons, such as secondary electrons, backscattered electrons, or Auger electrons, to be emitted from the surface. The generated secondary electrons can be emitted from the material structure of the sample. By scanning the primary electron beam as a probe spot across or across the sample surface, secondary electrons can be emitted throughout the sample surface. By collecting these emitted secondary electrons from the sample surface, the pattern evaluation system (or evaluation tool) can obtain an image that represents the characteristics of the material structure of the sample surface. The intensity of the electron beam, including backscattered and secondary electrons, can vary based on the characteristics of the internal and external structure of the sample, thereby indicating whether the sample has defects.

[0005] It is desirable to increase the throughput of evaluation systems, such as inspection systems, so that samples can be processed more quickly. In particular, it is desirable to increase the throughput, for example, to one wafer per hour. One technique for increasing the throughput of an evaluation system is to increase the number of charged particle devices, also called columns, positioned to scan each sample. However, there remains the problem of limited space in the evaluation system, for example, in the evaluation device portion of the evaluation system, such as the number of charged particle devices that can be accommodated in the evaluation device to scan a sample of a typical size. Such evaluation systems may be located within the production facilities of a chip fabrication plant, which can impose practical limitations on the size, e.g., footprint, of the evaluation. It is desirable for the system's footprint within the production facility to be as small as possible. Therefore, the present invention aims to increase the throughput of samples, for example, to address these constraints. Summary of the Invention

[0006]

[0006] An object of the present disclosure is to provide embodiments of charged particle devices and charged particle apparatus.

[0007] According to a first aspect of the present invention, there is provided a charged particle device for projecting multiple beams of charged particles toward a sample. The device includes a plurality of sources configured to emit respective source beams of charged particles comprising the plurality of charged particle beams along respective paths of a beam grid toward the sample. The device further includes one or more elements in which an array of apertures is defined. The one or more elements each include a plurality of beam regions assigned to a respective source beam. The one or more elements are configured to operate on the charged particle beams within the beam grid of the respective source beam. Each element is separated from an adjacent element by a spacer, the spacer having at least one aperture positioned to correspond to the positions of at least two of the beam regions.

[0008]

[0008] According to a second aspect of the present invention, a charged particle apparatus for projecting multiple beams of charged particles towards a sample is provided, the apparatus comprising a device and a stage configured to support the sample.

[0009]

[0009] The above and other aspects of the present disclosure will become more apparent from the description of exemplary embodiments read in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating an exemplary electron beam evaluation apparatus. [Figure 2]

[0011] 2 is a schematic diagram illustrating an exemplary multi-beam charged particle characterization system that is part of the exemplary electron beam characterization apparatus of FIG. 1. [Figure 3]

[0012] 1 is a schematic diagram of an exemplary multi-beam charged particle device. [Figure 4]

[0013] 1 is a schematic diagram of an exemplary electron optical system including a macro-collimator and a macro-scan deflector. [Figure 5]

[0014] 1 is a schematic diagram of an exemplary charged particle device including a collimator element array and a scanning deflector array. [Figure 6]

[0015] 1 is a schematic diagram of an exemplary multi-beam charged particle device. [Figure 7]

[0016] FIG. 1 is a schematic diagram providing a plan view of elements of a charged particle device, including a single beam region associated with a beam grid. [Figure 8]

[0017] 1 is a schematic diagram of a charged particle device comprising multiple subdevices, each containing a charged particle beam source. [Figure 9A]

[0018] FIG. 1 is a schematic diagram providing a top view of an element of a charged particle device including multiple beam regions, each associated with a different beam grid. [Figure 9B]

[0018] FIG. 1 is a schematic diagram providing a plan view of elements of a charged particle device, including multiple beam regions, each associated with a different beam grid. [Figure 9C]

[0018] FIG. 1 is a schematic diagram providing a plan view of elements of a charged particle device, including multiple beam regions, each associated with a different beam grid. [Figure 10]

[0019] FIG. 1 is a schematic diagram providing a plan view of elements of a charged particle device, including multiple beam regions arranged in multiple rings around an intermediate region. [Figure 11]

[0020] 9C is a schematic diagram of a charged particle apparatus including a charged particle device having a beam field arrangement as shown in FIG. 9B. DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0021] The schematic diagrams and views show the components described below, however, the components shown in the figures are not to scale.

[0012]

[0022] Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which, unless otherwise stated, like numbers in different drawings represent the same or similar elements. The implementations described in the following description of exemplary embodiments do not represent all implementations that are consistent with the present invention. Instead, they are merely examples of apparatus and methods that are consistent with aspects related to the present invention as recited in the appended claims.

[0013]

[0023] Increasing the computing power of electronic devices, which reduces their physical size, can be achieved by significantly increasing the packing density of circuit components such as transistors, capacitors, and diodes on IC chips. This is made possible by increasing resolution, which allows for the fabrication of ever-smaller structures. For example, a smartphone IC chip, the size of a thumbnail and available before 2019, can contain over 2 billion transistors, each one less than 1 / 1000 the size of a human hair. Therefore, manufacturing semiconductor ICs is a complex and time-consuming process involving many individual steps. An error in one of these steps can significantly affect the functionality of the final product. The goal of a manufacturing process is to improve the overall yield. For example, to achieve a 75% yield in a 50-step process (where a step can represent the number of layers formed on a wafer), the yield at each individual step must be greater than 99.4%. Even if the yield at each individual step is 95%, the overall process yield would be as low as 7%.

[0014]

[0024] While high process yields are desirable in IC chip manufacturing facilities, it is also important to maintain high substrate (i.e., wafer) throughput, defined as the number of substrates processed per hour. High process yields and high substrate throughput can be affected by the presence of defects. This is especially true when inspection of the defects requires operator intervention. Therefore, high-throughput detection and identification of microscale to nanoscale defects by characterization systems (such as or including scanning electron microscopes ("SEMs")) is essential to maintaining high yields and low costs.

[0015]

[0025] An SEM includes a scanning device and a detector device. The scanning device includes an illumination device, which includes an electron source for generating primary electrons, and a projection device for scanning a sample, such as a substrate, with one or more focused beams of primary electrons. At least the illumination device or illumination system and the projection device or projection system may collectively be referred to as an electron-optical system or apparatus. The primary electrons interact with the sample and generate secondary electrons. A detection device captures the secondary electrons from the sample as it is scanned, allowing the SEM to create an image of the scanned area of ​​the sample. Such evaluation devices may utilize a single primary electron beam incident on the sample. For high-throughput inspection, some evaluation devices use multiple focused beams of primary electrons, or multibeams. The component beams of a multibeam may be referred to as subbeams or beamlets. The subbeams may be positioned relative to each other within the multibeam in a multibeam configuration. The multibeam may simultaneously scan different portions of the sample. Thus, a multibeam evaluation device may evaluate, e.g., inspect, a sample much faster than a single-beam evaluation device.

[0016]

[0026] Known multi-beam characterization devices and system implementations are described below.

[0017]

[0027] The figures are schematic. Accordingly, relative dimensions of components in the figures have been exaggerated for clarity. Within the following description of the figures, identical or similar reference numbers refer to identical or similar components or entities, and only differences relative to individual embodiments are described. While the description and figures relate to electron-optical systems, it should be understood that the embodiments are not used to limit the present disclosure to particular charged particles. Thus, references to electrons throughout this specification may be considered to be references to charged particles more broadly, although charged particles are not necessarily electrons.

[0018]

[0028] Reference is now made to FIG. 1, which is a schematic diagram illustrating an exemplary charged particle beam evaluation apparatus 100. It should be noted that the evaluation apparatus includes a portion of the evaluation system, and in many cases, includes a portion of the evaluation system located within the fabrication facility. The evaluation apparatus may cover a surface area of ​​the fabrication facility floor, referred to as the equipment footprint. Other portions of the evaluation system, such as vacuum and fluid supply service systems and remote processing racks, may be located elsewhere in the fabrication facility, away from the fabrication system and equipment, where space is less of a critical requirement.

[0019]

[0029] 1 includes a main chamber 10, a load lock chamber 20, a charged particle evaluation system 40 (which may also be referred to as an electron beam system or tool), a front-end equipment module (EFEM) 30, and a controller 50. The charged particle evaluation system 40 is disposed in the main chamber 10.

[0020]

[0030] The EFEM 30 includes a first load port 30a and a second load port 30b. The EFEM 30 may include additional load ports. The first load port 30a and the second load port 30b may accept, for example, substrates (e.g., semiconductor substrates or substrates made of other materials) or substrate Front Opening Unified Pods (FOUPs) containing samples to be evaluated, e.g., measured or inspected (hereinafter, substrates, wafers, and samples are collectively referred to as "samples"). One or more robotic arms (not shown) within the EFEM 30 transport the samples to the load lock chamber 20.

[0021]

[0031] The load lock chamber 20 is used to remove gas from around the sample, creating a vacuum, which is a local gas pressure lower than the pressure of the surrounding environment. The load lock chamber 20 may be connected to a load lock vacuum pumping system (not shown) that removes gas particles from within the load lock chamber 20. Operation of the load lock vacuum pumping system allows the load lock chamber to reach a first pressure below atmospheric pressure. After the first pressure is reached, one or more robotic arms (not shown) transfer the sample from the load lock chamber 20 to the main chamber 10. The main chamber 10 is connected to the main chamber vacuum pumping system (not shown). The main chamber vacuum pumping system removes gas particles from the main chamber 10, so that the pressure around the sample reaches a second pressure lower than the first pressure. After the second pressure is reached, the sample is transferred to the charged particle evaluation system 40 and can be evaluated by it. The charged particle evaluation system 40 includes a charged particle device 41. The charged particle device 41 may be an electron-optical device, which may be synonymous with an electron-optical system. The charged particle device 41 may be a multi-beam charged particle device 41 configured to project multiple beams towards the sample, e.g., the sub-beams are arranged relative to each other in a multi-beam configuration. Alternatively, the charged particle device 41 may be a single-beam charged particle device 41 configured to project a single beam towards the sample.

[0022]

[0032] The controller 50 is electronically connected to the charged particle beam evaluation system 40. The controller 50 may be a processor (e.g., a computer) configured to control the charged particle beam evaluation device 100. The controller 50 may also include processing circuitry configured to perform various signal and image processing functions. While the controller 50 is shown in FIG. 1 as being external to the structure including the main chamber 10, the load lock chamber 20, and the EFEM 30, it should be understood that the controller 50 may be part of this structure. The controller 50 may be located within one of the component elements of the charged particle beam evaluation device or distributed among at least two of these components. While the present disclosure provides an example of a main chamber 10 housing an electron beam evaluation device, it should be noted that aspects of the present disclosure, in their broadest sense, are not limited to chambers housing electron beam evaluation devices. Rather, it should be understood that the principles described above may also be applied to other tools and other device configurations operating under a second pressure.

[0023]

[0033] Reference is now made to FIG. 2, which is a schematic diagram illustrating an exemplary charged particle characterization system 40 including a multi-beam charged particle device 41 that is part of the exemplary charged particle beam characterization apparatus 100 of FIG. 1. The multi-beam charged particle device 41 comprises an electron source 201 and a projection device 230. The charged particle characterization system 40 further comprises a motion stage 209 and a sample holder 207. The sample holder may have a holding surface (not shown) for supporting and holding the sample. Thus, the sample holder may be configured to support the sample. Such a holding surface may be an electrostatic clamp operable to hold the sample during operation of the charged particle device 41, e.g., during evaluation, e.g., measurement or inspection, of at least a portion of the sample. The holding surface may be recessed within a surface of the sample holder oriented facing the sample holder, e.g., the charged particle device 41. The electron source 201 and the projection device 230 may collectively be referred to as the charged particle device 41. The sample holder 207 is supported by a moving stage 209 to hold a sample 208 (e.g., a substrate or a mask) for evaluation. The multi-beam charged particle device 41 may further comprise a detector 240 (e.g., an electron detection device).

[0024]

[0034] The electron source 201 may include a cathode (not shown) and an extractor or anode (not shown). In operation, the electron source 201 is configured to emit electrons from the cathode as primary electrons. The primary electrons are extracted or accelerated by the extractor and / or anode to form a primary electron beam 202.

[0025]

[0035] The projection device 230 is configured to convert the primary electron beam 202 into multiple sub-beams 211, 212, 213 and direct each sub-beam to the sample 208. Although three sub-beams are shown for simplicity, there may be tens, hundreds, or thousands of sub-beams. The sub-beams may be referred to as beamlets.

[0026]

[0036] 1, such as the electron source 201, the detector 240, the projection device 230, and the motion stage 209. The controller 50 may perform various image and signal processing functions. The controller 50 may also generate various control signals to govern the operation of the charged particle beam evaluation device, including the charged particle multi-beam device.

[0027]

[0037] The projection device 230 may be configured to focus the sub-beams 211, 212, and 213 onto the sample 208 for evaluation and to form three probe spots 221, 222, and 223 on the surface of the sample 208. The projection device 230 may be configured to deflect the primary sub-beams 211, 212, and 213 to scan individual scan areas within a section of the surface of the sample 208 with the probe spots 221, 222, and 223. In response to the incidence of the primary sub-beams 211, 212, and 213 on the probe spots 221, 222, and 223 on the sample 208, electrons, including secondary electrons and backscattered electrons, are generated from the sample 208. Secondary electrons typically have electron energies of ≦50 eV. Actual secondary electrons may have energies less than 5 eV, but all electrons less than 50 eV are generally considered secondary electrons. Backscattered electrons typically have electron energies between 0 eV and the incident energy of the primary sub-beams 211, 212, and 213. Electrons detected with energies less than 50 eV are generally treated as secondary electrons, so some of the actual backscattered electrons will be counted as secondary electrons.

[0028]

[0038] The detector 240 is configured to detect signal particles, such as secondary electrons and / or backscattered electrons, and generate a corresponding signal that is transmitted to a signal processing system 280 to construct, for example, an image of a corresponding scanned area of ​​the sample 208. The detector 240 may be integrated into the projection device 230.

[0029]

[0039] The signal processing system 280 may include circuitry (not shown) configured to process signals from the detector 240 to form an image. The signal processing system 280 may otherwise be referred to as an image processing system. The signal processing system may be incorporated into a component of the multi-beam charged particle evaluation system 40, such as the detector 240 (as shown in FIG. 2). However, the signal processing system 280 may be incorporated into any component of the evaluation apparatus 100 or the multi-beam charged particle evaluation system 40, such as part of the projection device 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 include a processor, a computer, a server, a mainframe host, a terminal, a personal computer, any type of mobile computing device, etc., or a combination thereof. The image acquirer may include at least a portion of the processing functionality of the controller. Thus, the image acquirer may include at least one or more processors. The image acquirer may be communicatively coupled to the detector 240 to enable signal communication, such as via a conductor, fiber optic cable, portable storage medium, IR, Bluetooth, the Internet, a wireless network, wireless radio, or the like, or a combination thereof. The image acquirer may receive signals from the detector 240, process the data contained in the signals, and form an image therefrom. Thus, the image acquirer may acquire an image of the sample 208. The image acquirer may also perform various post-processing functions, such as contour generation and overlaying indicators on the acquired image. The image acquirer may be configured to perform adjustments, such as brightness and contrast, on the acquired image. The storage may be a storage medium, such as a hard disk, a flash drive, cloud storage, random access memory (RAM), or other type of computer-readable memory. The storage may be coupled to the image acquirer and used to store raw scanned image data as original images and post-processed images.

[0030]

[0040] The signal processing system 280 may include measurement circuitry (e.g., an analog-to-digital converter) to acquire the distribution of detected secondary electrons. The electron distribution data collected during the detection time window may be used in combination with the corresponding scan path data of each of the primary sub-beams 211, 212, and 213 incident on the sample surface to reconstruct an image of the sample structure under evaluation. The reconstructed image may be used to reveal various features of the internal or external structure of the sample 208. The reconstructed image may thereby be used to reveal any defects that may be present in the sample.

[0031]

[0041] The controller 50 may control the actuation stage 209 to move the sample 208 during evaluation, e.g., inspection, of the sample 208. The controller 50 may enable the actuation stage 209 to move the sample 208 in a direction, preferably continuously, e.g., at a constant velocity, at least during sample evaluation. The controller 50 may control the movement of the actuation stage 209 to vary the speed of movement of the sample 208 in response to various parameters. For example, the controller 50 may control the stage velocity (including its direction) in response to characteristics of the evaluation step of the scanning process.

[0032]

[0042] Known multi-beam systems, such as the above-described charged particle characterization system 40 and charged particle beam characterization apparatus 100, are disclosed in U.S. Patent Application No. 2020118784, U.S. Patent Application No. 20200203116, U.S. Patent Application No. 2019 / 0259570, and U.S. Patent Application No. 2019 / 0259564, which are incorporated herein by reference.

[0033]

[0043] 2, in one embodiment, the charged particle characterization system 40 has a single charged particle device 41 and, optionally, includes a projection assembly 60. The projection assembly 60 may be a module and may be referred to as an ACC module. The projection assembly 60 is positioned to direct a light beam 62 such that the light beam 62 is between the charged particle device 41 and the sample 208.

[0034]

[0044] As the electron beam scans the sample 208, a large beam current can cause charge to accumulate on the sample 208, which can affect the quality of the image. To regulate the accumulated charge on the sample, a projection assembly 60 can be used to project a light beam 62 onto the sample 208 to control the accumulated charge through effects such as photoconduction, photoelectric, or thermal effects.

[0035]

[0045] Components of a charged particle characterization system 40 that may be used in the present invention are described below in connection with Figure 3, which is a schematic diagram of a charged particle characterization system 40. The charged particle characterization system 40 of Figure 3 may correspond to the charged particle characterization system 40 (which may also be referred to as an apparatus or tool) described above.

[0036]

[0046] 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 preferably a high-brightness emitter configured to operate within an optimized electron-optical performance range, which is a compromise between brightness and total emission current (such a compromise may be considered a "good" compromise). The electron source emits a source beam. There may be tens, hundreds, or even thousands of condenser lenses 231. The condenser lenses 231 may include multi-electrode lenses and have a structure based on EP 1602121 A1, which is incorporated herein by reference, particularly for its disclosure of the lens array that splits the source beam into multiple sub-beams. The top beam plate, which may be referred to as a beam-limiting aperture array and may be the top beam plate of the condenser lens array, may generate multiple beams. The array condenser lenses (which may include a 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 that function as electrodes, with apertures in each plate aligned with one another and corresponding to the positions of the sub-beams, and at least two of the plates held at different potentials during operation to achieve the desired lensing effect.

[0037]

[0047] In one configuration, the array of condenser lenses 231 is formed from a three-plate array in which charged particles have the same energy as they enter and exit each lens; this configuration may be called an Einzel lens. Dispersion therefore occurs only within the Einzel lens itself (between the entrance and exit electrodes of the lens), thereby limiting off-axis chromatic aberration. If the condenser lens is thin, e.g., a few mm thick, the effect of such aberrations is small or negligible.

[0038]

[0048] Each condenser lens 231 in the array directs electrons into a respective sub-beam 211, 212, 213, which is focused to a respective intermediate focus downstream of the beam from the condenser lens array. The sub-beams diverge relative to one another. In one embodiment, a deflector 235 is provided at the intermediate focus. The deflector 235 is positioned within the sub-beam path at or at least around the location of the corresponding intermediate focus. The deflector 235 is positioned within or near the sub-beam path at the intermediate image plane of the associated sub-beam. The deflector 235 is configured to operate on each sub-beam 211, 212, 213. The deflector 235 is configured to bend each sub-beam 211, 212, 213 by an amount effective to ensure that the chief ray (also referred to as the beam axis) is incident on the sample 208 substantially normal to the surface (i.e., substantially 90° relative to the nominal surface of the sample). The deflector 235 may also be referred to as a collimator or collimator-deflector. The deflector 235 actually collimates the paths of the sub-beams, causing them to diverge relative to one another before the deflector. At the beam downstream of the deflector, the sub-beam paths are substantially parallel to one another, i.e., substantially collimated. A suitable collimator is the deflector disclosed in European Patent Application No. 20156253.5, filed February 7, 2020, which is incorporated herein by reference for its application to multi-beam arrays. In one configuration, the collimator may include a macro-collimator instead of or in addition to the deflector 235. The macro-collimator may be electrostatic, for example, as two or more flat plates with a single aperture.

[0039]

[0049] Below the deflector 235 (i.e., downstream of the beam or further from the source 201) is the control lens array 250. The sub-beams 211, 212, and 213 that pass through the deflector 235 are substantially parallel to the direction in which they enter the control lens array 250. The control lenses prefocus the sub-beams (e.g., apply a focusing action to the sub-beams before they reach the objective lens array 241). Prefocusing can reduce the divergence of the sub-beams or increase the convergence rate of the sub-beams. The control lens array 250 and the objective lens array 241 together provide a composite focal length. Their cooperative action without intermediate focuses can reduce the risk of aberrations. In one embodiment, the control lenses of the control lens array can be considered to be part of the objective lenses of the objective lens array. The electrode plates of the control lens array can be considered electro-optically as additional electrode plates of the objective lens array.

[0040]

[0050] It is desirable to use the control lens array 250 to determine the incident energy. However, it is also possible to control the incident energy using the objective lens array 241. In such a case, when a different incident energy is selected, the potential difference on the objective lens is changed. One example of a situation in which it is desirable to partially change the incident energy by changing the potential difference on the objective lens is to prevent the focal point of the sub-beams from being too close to the objective lens. In such a situation, there is a risk that the components of the objective lens array 241 would have to be made so thin that they cannot be manufactured. The same may be true for the detector at this position. This situation can arise, for example, when the incident energy is reduced. This is because the focal length of the objective lens roughly corresponds to the incident energy used. By reducing the potential difference on the objective lens, thereby reducing the electric field inside the objective lens, the focal length of the objective lens is again lengthened, resulting in a focal position further below the objective lens. It should be noted that when using only the objective lens, control of the magnification is limited. In such a configuration, the demagnification and / or the aperture angle cannot be controlled. Furthermore, using an objective lens to control the incident energy may mean that the objective lens operates at a field strength other than its optimum, if the mechanical parameters of the objective lens (such as the spacing between its electrodes) cannot be adjusted, for example by changing the objective lens.

[0041]

[0051] The control lens array 250 includes a plurality of control lenses. Each control lens includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The control lens array 250 may include two or more (e.g., three) plate electrode arrays connected to a respective potential source. The control lens array 250 is associated with the objective lens array 241 (e.g., two arrays positioned adjacent to each other and / or mechanically connected to each other and / or controlled together as a unit). Each control lens may be associated with a respective objective lens. The control lens array 250 is positioned beam upstream of the objective lens array 241.

[0042]

[0052] The control lens array 250 includes a control lens for each sub-beam 211, 212, 213. The function of the control lens array 250 is to optimize the beam aperture angle for beam reduction and / or 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 electro-optical device 41. The control lens array 250 is optional but is preferred for optimizing the sub-beams beam upstream of the objective lens array 241. In one configuration, 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 in addition to the functions of the objective lens array described herein.

[0043]

[0053] For ease of illustration, lens arrays are generally represented herein by an array of elliptical shapes (see FIG. 3, and for that matter FIGS. 5 and 6). Each elliptical shape represents one of the lenses in the lens array. By convention, the elliptical shape is used to represent a lens in analogy with the biconvex shape often adopted by optical lenses. However, it should be understood that in the context of charged particle configurations such as those discussed herein, lens arrays typically operate electrostatically and may not require any physical elements to adopt a biconvex shape. Instead, the lens array may include a plurality of plates having apertures.

[0044]

[0054] An array of scan deflectors 260 may be provided between the control lens array 250 and the array of objective lenses 234. The array of scan deflectors 260 includes a scan deflector for each evaluation sub-beam 211, 212, 213. Each scan deflector is configured to deflect a respective sub-beam 211, 212, 213 in one or two directions to scan the sub-beam across the sample 208 in one or two directions.

[0045]

[0055] As shown in FIG. 3, a schematic diagram of an exemplary charged particle device includes an objective lens array assembly. The objective lens array assembly includes an objective lens array 241. The objective lens array 241 includes multiple objective lenses. Each objective lens includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The objective lens array 241 may include two or more (e.g., three) plate electrode arrays connected to a respective potential source. Each objective lens formed by the plate electrode arrays may be a microlens that operates on a different sub-beam or group of sub-beams within the multi-beam. Each plate defines multiple apertures (also called holes). The position of each aperture in a plate corresponds to the position of a corresponding aperture (or corresponding hole) in another plate. The corresponding apertures define an objective lens, and each set of corresponding holes therefore operates on the same sub-beam or group of sub-beams within the multi-beam when in use. Each objective lens projects a respective sub-beam of the multi-beam onto the sample 208.

[0046]

[0056] The objective lens array assembly further includes a control lens array 250. The control lens array 250 includes a plurality of control lenses. Each control lens includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The control lens array 250 may include two or more (e.g., three) plate electrode arrays connected to a respective potential source. The control lens array 250 is associated with the objective lens array 241 (e.g., the two arrays are positioned adjacent to each other and / or mechanically connected to each other and / or controlled together as a unit). The control lens array 250 is positioned beam upstream of the objective lens array 241. The control lenses prefocus the sub-beams (e.g., apply a focusing action to the sub-beams before they reach the objective lens array 241). Prefocusing may reduce the divergence of the sub-beams or increase the convergence rate of the sub-beams. The control lens array and the objective lens array together provide a composite focal length. Cooperative operation without intermediate focuses may reduce the risk of aberrations. In one embodiment, the control lens array may be considered part of the objective lens array.

[0047]

[0057] In the configuration of FIG. 3 , the objective lens array assembly includes a scan deflector array 260. The scan deflector array 260 includes multiple scan deflectors. The scan deflector array 260 may be formed using MEMS fabrication techniques. Each scan deflector scans a respective sub-beam on or across the sample 208. Thus, the scan deflector array 260 may include a scan deflector for each sub-beam. Each scan deflector may deflect the light rays in a sub-beam in one direction (e.g., parallel to a single axis, such as the X-axis) or in two directions (e.g., about two non-parallel axes, such as the X-axis and the Y-axis). The deflection causes the sub-beam to scan across the sample 208 in one or two directions (i.e., one-dimensionally or two-dimensionally). In one embodiment, the scan deflector array 260 may be implemented using the scan deflector described in EP 2425444, which is incorporated herein by reference in its entirety, particularly with respect to the scan deflector. The scan deflector array 260 is positioned between the objective lens array 241 and the control lens array 250. In the embodiment shown, the scan deflector array 260 is provided in place of a macro scan deflector, such as an electrostatic scan deflector (not shown). The scan deflector array 260 may be more spatially compact than a macro scan deflector.

[0048]

[0058] The objective lens array assembly may include a detector 240. (Alternatively, the detector may be included in the charged particle device 41, without needing to be present in the objective lens array assembly.) The detector 240 may include a detector element (e.g., a sensor element such as a capture electrode). The detector 240 may include any suitable type of detector. For example, the detector element may be a charge-based detector configured to detect charge detected over time, for example, using a current, a scintillator, or a semiconductor device such as a PIN element. The detector 240 may be a direct current detector or an indirect current detector.

[0049]

[0059] The detector 240 may be positioned between the objective lens array 241 and the sample 208. The detector 240 is configured to be proximate to the beam-most downstream feature of the electron-optical device, e.g., the sample 208. The detector 240 may be very close to the sample 208, e.g., 5 mm, 3 mm, 1.5 mm, less than 300 μm, preferably 200 μm to 10 μm, more preferably 100 μm to 30 μm, e.g., 40 μm to 70 μm.

[0050]

[0060] The detector 240 may be positioned within the device facing the sample 208. Alternatively or additionally, the detector 240 may be positioned elsewhere in the electron-optical system 41 such that the portion of the electron-optical device facing the sample 208 is other than the detector, and therefore not a detector, such as an electrode of an objective lens arrangement. In such a configuration, another element of the electron-optical device, such as an electrode plate of an objective lens, may face the sample during operation. In all these configurations, the most downstream element of the electron-optical system, such as the detector 240, is closest to the sample. The most downstream surface of the most downstream element may face the sample. The most downstream surface may be referred to as the facing surface.

[0051]

[0061] The bottom surface of the detector 240 (or the facing surface of the detector 240 that may face the sample 208 in use) may include a substrate on which a plurality of detector elements are provided. Each detector element may surround a beam aperture. The beam aperture may be formed by etching through the substrate. In this configuration, the beam aperture is a hexagonal close-packed array, or alternatively a rectangular array. The detector elements may be arranged in a rectangular array or a hexagonal array.

[0052]

[0062] In a cross section of the detector, the detector elements form the bottom-most portion of the detector 240, i.e., the portion closest to the sample 208. A logic layer may be provided between the detector elements and the body of the substrate. At least a portion of the signal processing system may be incorporated into the logic layer. A wiring layer may be provided on or within the backside of the substrate and connected to the logic layer by through-substrate vias. The wiring layer may include control lines, data lines, and power lines. A printed circuit board and / or other semiconductor chip may be provided on, e.g., connected to, the backside of the detector 240.

[0053]

[0063] The detector 240 can 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. Integrating the detector 240 into the objective lens array 241 or other components of the electron optical system 41 allows for detection of electrons emitted in association with each of the multiple sub-beams. The CMOS chip can embody a detector that can be oriented facing the sample. In one embodiment, the detector elements that capture secondary charged particles are formed in a surface metal layer of the CMOS device. The detector elements can be formed in other layers. CMOS power and control signals can be connected to the CMOS by through-silicon vias. A passive silicon substrate with holes shields the CMOS chip from high electric fields, providing, for example, robustness.

[0054]

[0064] To maximize detection efficiency, it is desirable to make the detector element surface as large as possible, so that substantially all of the area of ​​the objective lens array 240 (excluding the apertures) is occupied by the detector elements. Additionally or alternatively, each detector element has a diameter substantially equal to the array pitch (i.e., the pitch of the apertures in the aperture array in the electrodes of the objective lens assembly 241). The diameter of each detector element can be less than about 600 μm, preferably about 50 μm to 500 μm. The pitch can be selected depending on the intended distance between the sample 208 and the detector 240. In one embodiment, the outer shape of the detector elements is circular, but this can be squared to maximize the detection area. The diameter of the through-substrate vias can be minimized. Typical sizes of electron beams are on the order of 5 to 15 micrometers.

[0055]

[0065] In one embodiment, a single detector element surrounds each beam aperture, while in another embodiment, multiple detector elements are provided around each beam aperture.

[0056]

[0066] FIG. 4 is a schematic diagram of an exemplary electron-optical system having an objective lens array assembly. The objective lens array assembly includes an objective lens array 241. The objective lens array 241 includes multiple objective lenses. Each objective lens includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The objective lens array 241 may include two or more (e.g., three) plate electrode arrays connected to a respective potential source. Each objective lens formed by the plate electrode arrays may be a microlens that operates on a different sub-beam or group of sub-beams within the multi-beam. Each plate defines multiple apertures (also called holes). The position of each aperture in a plate corresponds to the position of a corresponding aperture (or corresponding hole) in another plate. The corresponding apertures define an objective lens, and each set of corresponding holes therefore operates on the same sub-beam or group of sub-beams within the multi-beam when in use. Each objective lens projects a respective sub-beam of the multi-beam onto the sample 208.

[0057]

[0067] For ease of illustration, lens arrays are generally represented herein by an array of elliptical shapes. Each elliptical shape represents one of the lenses in the lens array. By convention, the elliptical shape is used to represent a lens in analogy with the biconvex shape often adopted by optical lenses. However, it should be understood that in the context of charged particle configurations such as those discussed herein, lens arrays typically operate electrostatically and may not require any physical elements to adopt a biconvex shape. As mentioned above, lens arrays may include multiple plates having apertures.

[0058]

[0068] The objective lens array assembly further includes a control lens array 250. The control lens array 250 includes a plurality of control lenses. Each control lens includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The control lens array 250 may include two or more (e.g., three) plate electrode arrays connected to a respective potential source. The control lens array 250 is associated with the objective lens array 241 (e.g., the two arrays are positioned adjacent to each other and / or mechanically connected to each other and / or controlled together as a unit). The control lens array 250 is positioned beam-upstream of the objective lens array 241. The control lenses prefocus the sub-beams (e.g., apply a focusing action to the sub-beams before they reach the objective lens array 241). Prefocusing may reduce the divergence of the sub-beams or increase the convergence rate of the sub-beams. The control lens array and the objective lens array together provide a composite focal length. Cooperative operation without intermediate focus may reduce the risk of aberrations.

[0059]

[0069] In one embodiment, the electron-optical system including the objective lens array assembly is configured to control the objective lens assembly (e.g., by controlling the potentials applied to electrodes of the control lens array 250) so that the focal length of the control lens is greater than the spacing between the control lens array 250 and the objective lens array 241. Thus, the control lens array 250 and the objective lens array 241 can be positioned relatively close together such that the focusing action from the control lens array 250 is too weak to form an intermediate focus between the control lens array 250 and the objective lens array 241. In other embodiments, the objective lens array assembly can be configured to form an intermediate focus between the control lens array 250 and the objective lens array 241.

[0060]

[0070] In one embodiment, the control lens array is a replaceable module, alone or in combination with other elements such as the objective lens array and / or detector array. The replaceable module may be field replaceable, i.e., the module can be replaced with a new module by a field engineer. In one embodiment, multiple replaceable modules are housed within a tool and can be swapped between operable and inoperable positions without opening the tool.

[0061]

[0071] In one embodiment, the replaceable module includes an electron-optical component on a stage that allows actuation for component positioning. In one embodiment, the replaceable module includes a stage. In one configuration, the stage and the replaceable module can be integral parts of the charged particle device 41. In one configuration, the replaceable module is limited to the stage and the electron-optical device it supports. In one configuration, the stage is removable. In an alternative design, the replaceable module including the stage is removable. The portion of the electron-optical tool 40 for the replaceable module is separable; that is, this portion of the charged particle system 40 is defined by valves upstream and downstream of the replaceable module. The valves can be operated to isolate the environment between the valves from the vacuum upstream and downstream of the valves, respectively, thereby allowing the replaceable module to be removed from the charged particle system 40 while maintaining the vacuum upstream and downstream of the portion of the column associated with the replaceable module. In one embodiment, the replaceable module includes a stage. The stage is configured to support the electron-optical device with respect to the beam path. In one embodiment, the module includes one or more actuators. An actuator is associated with the stage and configured to move the electro-optical device relative to the beam path. Such actuation can be used to align the electro-optical device with respect to the beam path and each other.

[0062]

[0072] In one embodiment, the replaceable module is a MEMS module. In one embodiment, the replaceable module is configured to be replaceable within the electro-optical device 41. In one embodiment, the replaceable module is configured to be field replaceable. Field replaceable is intended to mean that a module can be removed and replaced with the same or a different module while maintaining the internal vacuum in which the charged particle device 41 is located. Only a portion of the column is vented, which corresponds to the module being removed and vented for the module to be replaced or replaced.

[0063]

[0073] The control lens array may be in the same module as the objective lens array 241, ie, forming an objective lens array assembly or objective lens arrangement, or may be in a separate module.

[0064]

[0074] A power supply may be provided to apply respective potentials to electrodes of the control lenses of the control lens array 250 and the objective lenses of the objective lens array 241 .

[0065]

[0075] The provision of the control lens array 250 in addition to the objective lens array 241 provides an additional degree of freedom for controlling the characteristics of the sub-beams. Even if the control lens array 250 and the objective lens array 241 are provided relatively close to each other, an additional degree of freedom is provided, for example, so that an intermediate focus is not formed between the control lens array 250 and the objective lens array 241. The control lens array 250 can be used to optimize the beam aperture angle for beam demagnification and / or to control the beam energy delivered to the objective lens array 241. The control lens can include two or more electrodes. When there are two electrodes, the demagnification ratio and incident energy are controlled together. When there are three or more electrodes, the demagnification ratio and incident energy can be controlled independently. Thus, the control lens can be configured to adjust the demagnification ratio and / or beam aperture angle of each sub-beam (e.g., by applying appropriate respective potentials to the electrodes of the control lens and the objective lens using a power supply). This optimization can be achieved without unduly adversely affecting the number of objective lenses and without unduly exacerbating the aberrations of the objective lenses (eg, without increasing the strength of the objective lenses).

[0066]

[0076] In the embodiment of FIG. 4, the electron optical system includes a source 201. The source 201 provides a beam of charged particles (e.g., electrons). Multiple beams focused on the sample 208 are derived from the beam provided by the source 201. Sub-beams may be derived from the beam using, for example, a beam limiter defining an array of beam-limiting apertures. 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 in the beam upstream of the objective lens array assembly. The collimator may include a macro-collimator 270. The macro-collimator 270 acts on the beam from the source 201 before the beam is split into multiple beams. The macro-collimator 270 bends respective portions of the beam by an amount effective to ensure that the beam axis of each of the sub-beams derived from the beam is incident on the sample 208 substantially normal to the surface (i.e., substantially 90° relative to the nominal surface of the sample 208). The macro-collimator 270 applies macroscopic collimation to the beam. Thus, rather than including an array of collimator elements configured to each act on a different individual portion of the beam, the macro-collimator 270 may act on the entire beam. The macro-collimator 270 may include a magnetic lens or a magnetic lens configuration including multiple magnetic lens subunits (e.g., multiple electromagnets forming a multipole configuration). Alternatively or additionally, the macro-collimator may be implemented at least partially electrostatically, e.g., entirely electrostatically. The macro-collimator may include an electrostatic lens or an electrostatic lens configuration including multiple electrostatic lens subunits. The macro-collimator 270 may use a combination of magnetic and electrostatic lenses. Desirably, the macro-collimator 270 uses only electrostatic lenses.

[0067]

[0077] In the embodiment of FIG. 4 , a macroscan deflector 265 is provided to cause the sub-beams to scan over the sample 208. The macroscan deflector 265 deflects each portion of the beam to cause the sub-beams to scan over the sample 208. In one embodiment, the macroscan deflector 256 includes a macroscopic multipole deflector, e.g., having eight or more poles. The macroscan deflector can be electrostatic or magnetic. The deflection, for example, causes sub-beams derived from the beam to scan over the sample 208 in one direction (e.g., parallel to a single axis, such as the X axis) or in two directions (e.g., about two non-parallel axes, such as the X axis and the Y axis). The macroscan deflector 265 acts macroscopically on the entire beam, rather than including an array of deflector elements each configured to act on a different individual portion of the beam. In the embodiment shown, the macroscan deflector 265 is provided between the macrocollimator 270 and the control lens array 250.

[0068]

[0078] The electron-optical system of FIG. 4 further includes a detector (not shown), such as detector 240 described above in connection with FIG. 3, which may desirably be a detector array.

[0069]

[0079] 5, the control lens array 250 is the first deflecting or lensing electron-optical array element in the beam path downstream of the source 201. Such an embodiment may, for example, have a first beam-limiting array 252 for generating multiple beams from a source beam emitted by the source 201. The beam-limiting array 252 may be the first electron-optical element downstream of the source 201. The control lens array 250 may include a beam-limiting array 252.

[0070]

[0080] In the embodiment of FIG. 5, a collimator element array 271 is provided instead of a macro-collimator, which may be a two or more plate electrostatic collimator with a single aperture (which may be in the form of a macro-collimating lens, e.g., an electrostatic lens). The collimator element array 271 may be more spatially compact than the macro-collimator 270. Therefore, providing the collimator element array 271 together with the scan deflector array 260 may provide space savings. This space savings is desirable when multiple electron-optical systems, including objective lens array assemblies, are provided within the electron-optical system array. In such an embodiment, the macro-condenser lens or condenser lens array may not be present. Therefore, in this scenario, the control lens provides the possibility of optimizing the beam aperture angle and magnification for changes in incident energy.

[0071]

[0081] In some embodiments, as illustrated in FIG. 5, collimator element array 271 is the first deflection or focus electron optical array element in the beam path downstream of the source 201 beam.

[0072]

[0082] Avoiding any deflecting or lensing electron-optical array elements (e.g., lens arrays or deflector arrays) upstream of the control lens array 250 or the collimator element array 271 reduces the requirements for electron-optical systems upstream of the objective lens and for correctors to correct imperfections in such optical systems. For example, some alternative configurations attempt to maximize source current utilization by providing a condenser lens array in addition to the objective lens array. Providing a condenser lens array and an objective lens array in this manner either imposes stringent requirements on the uniformity of the virtual source position across the source aperture angle or requires a correction optical system for each sub-beam to ensure that each sub-beam passes through the center of the corresponding objective lens beam downstream. An architecture such as that of FIG. 5 allows the beam path from the first deflecting or lensing electron-optical array element to the beam-shaping limiter 242 to be reduced to less than about 10 mm, preferably less than about 5 mm, and preferably less than about 2 mm. Reducing the beam path reduces or eliminates the stringent requirements on the virtual source position relative to the source aperture angle.

[0073]

[0083] Providing a scan deflector array 260 instead of a macro scan deflector can reduce aberrations from the control lens. This is because the scanning motion of the macro scan deflector causes a corresponding movement of the beam on the beam-shaping limiter (also called the lower beam limiter), which defines an array of beam-limiting apertures downstream of at least one electrode of the control lens, thereby increasing the aberration contribution from the control lens. If the scan deflector array 260 is used instead, the beam is moved by a much smaller amount on the beam-shaping limiter. This is because the distance from the scan deflector array 260 to the beam-shaping limiter is much shorter. For this reason, it is preferable to position the scan deflector array 260 as close as possible to the objective lens array 241 (e.g., so that the scan deflector array 260 is directly adjacent to the objective lens array 241, as shown in FIG. 5). The smaller the movement on the beam-shaping limiter, the smaller the portion of each control lens used. Therefore, the control lens has a smaller contribution to aberrations. To minimize or at least reduce aberrations contributed by the control lens, a beam-shaping limiter is used to shape the beam downstream from at least one electrode of the control lens. This differs architecturally from conventional systems in which the beam-shaping limiter is provided only as part of or an associated aperture array of the first manipulator array in the beam path, typically generating multiple beams from a single beam from a source. In one configuration, the beam-shaping limiter 242 is structurally integrated with the electrodes of the objective lens array 241. Desirably, the beam-shaping limiter 242 is positioned in an area of ​​low electrostatic field strength. Each beam-limiting aperture of the beam-shaping limiter 242 is aligned with a corresponding objective lens in the objective lens array 241. The alignment is such that a portion of the sub-beams from the corresponding objective lens can pass through the beam-limiting aperture and impinge on the sample 208. Each beam-limiting aperture has a beam-limiting effect, thereby allowing only a selected portion of the sub-beam incident on the beam-shaping limiter 242 to pass through the beam-limiting aperture.The selected portions may be such that only a portion of each sub-beam that passes through a central portion of a respective aperture of the objective lens array reaches the sample, and the central portion may have a circular cross-section and / or may be centered on the beam axis of the sub-beam.

[0074]

[0084] In other embodiments, for example, various variations of the configurations shown in and described with reference to Figures 4-5, both a macro scan deflector 265 and a scan deflector array 260 are provided. In such configurations, scanning of the sub-beams over the sample surface can be achieved by jointly, preferably synchronously, controlling the macro scan deflector and the scan deflector array 260. Variations can include both a macro collimator 270 and a collimator array 271 to distribute the collimation action throughout the array.

[0075]

[0085] In one embodiment, an electron-optical system array is provided. The array may include any of the electron-optical systems described herein. Each electron-optical system simultaneously focuses a respective multibeam onto a different region of the same sample. Each electron-optical system may form subbeams from a beam of charged particles from a different respective source 201. Each source 201 may be one of the multiple sources 201. At least a subset of the multiple sources 201 may be provided as a source array. The source array may include multiple sources 201 provided on a common substrate. Simultaneously focusing multiple multibeams onto different regions of the same sample allows for an increased area of ​​the sample 208 to be simultaneously processed (e.g., evaluated). The electron-optical systems in the array may be positioned adjacent to each other to project each multibeam onto adjacent regions of the sample 208. Any number of electron-optical systems may be used in the array. Preferably, the number of electron-optical systems ranges from 9 to 200. In one embodiment, the electron-optical systems are arranged in a rectangular or hexagonal array. In other embodiments, the electron-optical systems are provided in an irregular array or a regular array having a geometric shape other than rectangular or hexagonal. Each electron-optical system in the array may be configured in any of the ways described herein when referring to a single electron-optical system. As noted above, the scan deflector array 260 and collimator element array 271 are particularly suitable for incorporation into an electron-optical system array due to their spatial compactness, which facilitates positioning the electron-optical systems in close proximity to one another.

[0076]

[0086] In some embodiments, for example as illustrated in FIG. 5 , the objective lens array assembly, which is a unit including the objective lens array 241, further includes a beam-shaping limiter 242. The beam-shaping limiter 242 defines an array of beam-limiting apertures. The beam-shaping limiter 242 may be referred to as a lower beam-shaping limiting aperture array or a final beam-limiting aperture array. The beam-shaping limiter 242 may include a plate (which may be a plate-like body) having a plurality of apertures. The beam-shaping limiter 242 may be located beam-downstream from at least one electrode (optionally from all electrodes) of the control lens array 250. In some embodiments, the beam-shaping limiter 242 is located beam-downstream from at least one electrode (optionally from all electrodes) of the objective lens array 241.

[0077]

[0087] In some embodiments, the charged particle device 41 further comprises an upper beam limiter 252 in addition to, for example, the beam-shaping limiter 242, for example, as shown in and described with reference to FIG. 5 . The upper beam limiter 252 defines an array of beam-limiting apertures. The upper beam limiter 252 may be referred to as an upper beam-limiting aperture array or a beam-upstream limiting aperture array. The upper beam limiter 252 may include a plate (which may be a plate-shaped body) having multiple apertures. The upper beam limiter 252 may be a beam-limiting array. The upper beam limiter 252 forms sub-beams from the beam of charged particles emitted by the source 201. Portions of the beam other than those contributing to the formation of the sub-beams may be blocked (e.g., absorbed) by the upper beam limiter 252 so as not to interfere with downstream sub-beams. The charged particles projected through the apertures of the upper beam limiter 252 may form sub-beams. The upper beam limiter 252 may be referred to as a sub-beam-defining aperture array.

[0078]

[0088] Any of the objective lens array assemblies described herein may further include a detector 240 having any of the described features. The detector detects electrons emitted from the sample 208. The detected electrons may include any of the electrons detected by the SEM, including secondary electrons and / or backscattered electrons emitted from the sample 208.

[0079]

[0089] Figure 6 shows a schematic diagram of a charged particle characterization system 40 according to one embodiment. Features that are the same as those described above are given the same reference numerals. For brevity, such features are not described in detail with respect to Figure 6. For example, the source 201, the condenser lens 231, the macro-collimator 270, the objective lens array 241, and the sample 208 may be as described above.

[0080]

[0090] As described above, in one embodiment, detector 240 is between objective lens array 241 and sample 208. Detector 240 may face sample 208. Alternatively, as shown in Figure 6, in one embodiment, objective lens array 241 including multiple objective lenses is between detector 240 and sample 208. Detector 240 may have all the features of the embodiments previously described with reference to Figures 3 and 5, for example, except as noted herein.

[0081]

[0091] In one embodiment, the deflector array 95 is between the detector 240 and the objective lens array 241. In one embodiment, the deflector array 95 includes a Wien filter (or even a Wien filter array), so that the deflector array may be referred to as a beam separator. The deflector array 95 is configured to provide a magnetic field to decouple charged particles projected onto the sample 208 from secondary electrons from the sample 208. However, it is preferred that the system include electrostatic components rather than magnetic components.

[0082]

[0092] In one embodiment, the detector 240 is configured to detect signal particles by reference to the energy of the charged particles, i.e., depending on the bandgap. Such a detector can be a semiconductor-based detector, such as a PIN detector or a scintillator (optically connected to a photon converter or photon-to-electron converter). Such a detector 240 can be referred to as an indirect current detector. Secondary electrons emitted from the sample 208 gain energy from the electric field between the electrodes. The secondary electrodes have sufficient energy once they reach the detector 240.

[0083]

[0093] The control lens array 250 may be in the same module as the objective lens array 241, i.e. forming part of the objective lens array assembly, or in one type of term, the objective lens array, or may be in a separate module.

[0084]

[0094] For example, in some embodiments of any of the embodiments described with reference to and shown in FIGS. 3, 5, and 6, one or more aberration correctors are provided to reduce one or more aberrations in the sub-beams. In any of the embodiments, the one or more aberration correctors may be provided, for example, as part of the charged particle optical device, as part of the optical lens array assembly, as part of the evaluation system, and / or as part of the electron-optical configuration. In one embodiment, at least a subset of the aberration correctors are each positioned at or directly adjacent to a corresponding one of the intermediate foci (e.g., in or adjacent to the intermediate image plane). The sub-beams have a smallest cross-sectional area in or near a focal plane, such as the intermediate plane. This provides more space for the aberration correctors than is available elsewhere, i.e., beam upstream or beam downstream of the intermediate plane (or than is available in alternative configurations without an intermediate image plane).

[0085]

[0095] In one embodiment, an aberration corrector positioned at or immediately adjacent to the intermediate focus (or intermediate image plane) includes a deflector to correct for sources 201 that appear to be in different positions for different beams. The corrector can be used to correct for macroscopic aberrations resulting from sources that prevent good alignment between each sub-beam and the corresponding objective lens.

[0086]

[0096] The aberration correctors may correct aberrations that prevent proper column alignment. Such aberrations may also lead to misalignment between the sub-beams and the correctors. Therefore, it may be desirable, additionally or alternatively, to position the aberration correctors at or near the condenser lens 231 (e.g., each such aberration corrector is integrated with or directly adjacent to one or more of the condenser lenses 231). This is desirable because at or near the condenser lens 231, the condenser lens is close to perpendicular to or coincides with the beam aperture, so that the corresponding sub-beams have not yet been shifted by aberrations. However, a challenge with positioning the correctors at or near the condenser lens is that each of the sub-beams has a relatively larger cross-sectional area and a relatively smaller pitch at this location than at locations further downstream. The aberration corrector may be a CMOS-based individually programmable deflector as disclosed in EP 2702595 A1, or an array of multipole deflectors as disclosed in EP 2715768 A2, the descriptions of beamlet manipulators in both of these documents being incorporated herein by reference.

[0087]

[0097] In some embodiments, each of at least a subset of the aberration correctors is integrated with or directly adjacent to the objective lens array 241. In one embodiment, these aberration correctors reduce one or more of field curvature, focus error, and astigmatism. Additionally or alternatively, one or more scan 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 one embodiment, the scan deflectors described in U.S. Patent Application Publication No. 2010 / 0276606 may be used, the entirety of which is incorporated herein by reference.

[0088]

[0098] 2 (when read in the context of charged particle device 41 as shown in and described with respect to FIGS. 3-6), in one embodiment, projection assembly 60 optionally includes optical system 63. In one embodiment, projection system 60 comprises source 61. Source 61 is configured to emit light beam 62. As described above, projection assembly 60 is used to illuminate light beam 62 onto sample 208, thereby controlling charge accumulation due to effects such as photoconductivity, photoelectric effect, or thermal effect, and therefore modulating charge accumulation on the sample.

[0089]

[0099] In one embodiment, optical system 63 includes a cylindrical lens 64. Cylindrical lens 64 is configured to focus light beam 62 in one direction rather than an orthogonal direction. The cylindrical lens provides greater freedom in the design of source 61. In one embodiment, source 61 is configured to emit light beam 62 having a circular cross-section.

[0090]

[0100] It is not essential that a cylindrical lens 64 is provided. In alternative embodiments, other optical components that can be focused more strongly in one direction than in another can be used. In alternative embodiments, the source is configured to emit a light beam 62 that is, for example, elliptical or rectangular. This is desirable to ensure that the light beam reaches the part of the sample that needs to be illuminated, despite the small dimension between the sample and the most downstream surface of the charged particle device 41, and the large dimension of the downstream surface of the electron-optical device that is orthogonal to the beam path orientation.

[0091]

[0101] In one embodiment, the optical system 63 includes reflective surfaces 65, 66, such as mirrors. For example, two reflective surfaces 65, 66 may be provided. In an alternative embodiment, the optical system 63 does not reflect the light beam 62. The number and arrangement of reflective surfaces may be selected depending on the size of the volume that the projection system 60 needs to fit into. Such reflective surfaces may be desirable to improve the reach of the light beam 62 between the sample and the downstream beam surface of the charged particle device.

[0092]

[0102] The projection optical assembly 60 may exist in one or more other embodiments. In one configuration, the path of light from the source 61 may at least partially pass through the charged particle device 41; for example, the path of light may pass up the beam of the objective lens array 240 into the charged particle device and be reflected by a reflective surface 65 within the charged particle device 41 toward the sample, e.g., through an aperture defined in a plate defining the objective lens array and other charged particle optical elements of the charged particle device. In one embodiment, the source may be proximate to, e.g., around, and / or adjacent to the source 201, such that the path of light toward the sample passes through all elements of the charged particle device 41. In another embodiment, the path of light may pass through a light guide from the source to the objective lens array, e.g., as disclosed in European Patent Application Publication No. 22204243.4, filed October 27, which is incorporated herein by reference at least insofar as it discloses an optical light guide for output coupling light toward the sample. Light may be coupled out to illuminate the sample from a location closer to the path of beams 211, 212, 213 than shown in and described with reference to Figure 2. Additionally or alternatively, light is coupled into an optical path within a charged particle element (e.g., a facing element) that is adjacent, such as facing sample 208 during operation. The light is coupled out near or from an aperture defined in the facing element.

[0093]

[0103] The invention disclosed herein may be applied to a variety of different tools or charged particle device architectures. The charged particle device comprises multiple rows of multi-beam (or multi-beam devices). Each row may be a charged particle device, such as the charged particle device 41, described in any of the above embodiments or aspects. As multiple rows (e.g., compromised in a multi-row device) may be multiple devices (or a multi-device array), the devices may be arranged in an array that may number from 2 to 100 or more devices (or may number from 2 to 100 rows). The charged particle device may take the form of an embodiment such as that shown in FIG. 4, which is an apparatus comprising multiple charged particle devices 41 as described above with reference to FIG. 5. The charged particle device preferably includes an electrostatic scan deflector array and an electrostatic collimator array. The charged particle device may optionally include a source. Note that in different configurations, the devices in the multi-device array may have any suitable design, such as those shown in and described with reference to FIG. 3 or FIG. 6 (not shown).

[0094]

[0104] 7 shows a plan view of an element 300, an element defining an array of apertures, e.g., an electron-optical element for interacting with charged particles, e.g., operating on charged particles of the primary beam. Such an electron-optical element may be one or more of the following features: an objective lens array or a condenser lens array, or a part thereof, e.g., lens arrays 231, 241, 250; a collimator 235, 271, 270, e.g., collimator array 235, 271, which may be collimated by lensing, e.g., lensing of collimators 235, 270, and / or by deflection 271; a scanning deflector array 260, 265; a limiting aperture array 231, 242, 252 for generating and / or shaping the charged particle beam; or a detector array 240 for detecting charged particles of the primary beam and / or from the sample 208. Element 300 is included in the charged particle device 41. In one configuration, the elements may span the entire cross section of the charged particle device 41 .

[0095]

[0105] Each of the embodiments illustrated in Figures 3-6 as described above includes a charged particle device 41 having a source 201. The source is configured to emit a respective source beam of charged particles along a respective path of a beam grid toward a sample. The beam grid includes a plurality of charged particle beams. Elements 300 are configured to interact with the charged particles, e.g., operate on the charged particle beams within the beam grid of individual source beams. The elements 300 include beam regions 70 assigned to the source beams emanating from the source 201 of the charged particle device 41. The beam regions 70 are areas on the surface of the element 300 spanned by the beam grid. One or more apertures may be defined in the element. An aperture may correspond to a beam path of the beam grid, a group of beam paths of the beam grid, or all beam paths of the beam grid (i.e., paths of the beam grid).

[0096]

[0106] The element 300 may be separated from adjacent elements arranged beam-downstream of the element 300 by spacers 80. The element 300 and the adjacent elements may be, for example, electrodes. In particular, the element 300 and the adjacent elements may be a pair of electrode plates. The element and the adjacent elements may include at least a portion of a lens array, such as the control lens array 250 or the condenser lens array 231. The spacers may provide physical separation between the element 300 and the adjacent elements in the direction of the path of the beam grid. The spacers may support the elements to which the spacers are connected, such as the element 300 and the adjacent elements. In a stack of elements (e.g., multiple elements stacked on top of each other with interleaved spacers), the spacers may provide structural or mechanical rigidity to the stack of elements. The spacers may insulate elements, such as the element 300, from adjacent elements. The spacers may electrically isolate, for example, the elements to which the spacers are connected, such as the element 300 and the adjacent elements. In a different embodiment, the spacer may be conductive so that no potential difference is applied between the connected elements, for example between element 300 and an adjacent element, i.e., the connected elements have the same potential difference relative to other elements of the charged particle device 41.

[0097]

[0107] FIG. 7 shows a space region 85. The space region 85 is disposed between 70 and 80, which is part of the substrate of element 300. The space region 85 may be sized to be sufficiently large between the beam region and the spacer, and may be empty, for example, to reduce the possibility of unwanted discharges at the surface of the spacer 80. The space region 85 optionally includes dummy apertures to reduce edge effects around the beam region and / or vents for fluid conductance, pressure control, and contamination suppression. The space region 85 covers the distance between the beam region 70 and the nearest spacer 80. The shortest distance between the beam region 70 and the space 80 nearest to that beam region 70 is desirably equal to or greater than a predetermined threshold distance that is large enough to limit the possibility of unwanted discharges.

[0098]

[0108] FIG. 7 shows an access area 90 that represents an area of ​​the charged particle device 41 that is used to provide service connections to one or more elements of the charged particle device 41, such as electrical connections, connections for control and data signals, cooling fluids, feedthroughs, connections between service connections and feedthroughs, and to gain access to components, for example, during maintenance.

[0099]

[0109] The invention disclosed herein can be applied to a variety of different charged particle device architectures. As shown, for example, in FIG. 8, a charged particle device 41 comprises multiple subdevices 42, each of which can be described in any of the embodiments or aspects described above. As a plurality of devices (or a multi-device array, e.g., included in a multi-device device), the devices can be arranged in an array that can range from 2 to 100 or more devices. Such a device 41 can be referred to as a multi-device 41 (or a charged particle multi-device).

[0100]

[0110] The charged particle device may take the form of the embodiment shown in FIG. 8, which is a charged particle device including a plurality of sub-devices 42, the reference numerals having the meanings described above with reference to FIG. 3. The charged particle device preferably comprises an electrostatic scan deflector array and an electrostatic collimator array. The charged particle device 41 comprises a plurality of sources 201. It should be noted that in a different configuration, the devices in the multi-device array may have any suitable design as shown in and described with reference to FIGS. 4 to 6 (not shown). Each source 201 is configured to emit a respective source beam of charged particles along a respective path of a beam grid towards the sample 208. The beam grid includes a plurality of charged particle beams, which may be called sub-beams or beamlets.

[0101]

[0111] In a configuration with multiple subdevices, such as that of Figure 8, it is possible to reduce the number of components compared to a system including multiple separate charged particle devices, each with a corresponding source, to provide a comparable number of beam regions. Thus, for example, as shown in Figures 9A-9C (which provide a plan view of element 300', which may have equivalent electron-optical functionality to element 300 of Figure 7), in a configuration such as that of Figure 8, there may be multiple beam regions, each corresponding to one of multiple sources. Note that in Figures 9A-9C, common reference numbers in these different figures indicate similar features, which may be differently sized in different embodiments (e.g., having similarly sized beam regions).

[0102]

[0112] Each beam region may correspond to a different source, e.g., the surface area of ​​elements 300 assigned to a beam grid derived from the source. The surface area of ​​the beam region and the elements 300, 300' assigned to each beam grid may be larger than that required by the beam grid. This is shown, for example, in Figures 9A-9C by different beam grids 70a-70e having outer concentric boundaries that form an annulus or ring around the periphery of each beam region. This annular region desirably ensures sufficient spacing between adjacent beam regions to account for alignment tolerances and reduce the possibility of interference (or crosstalk) between adjacent beam grids. For example, an annular region around or around each beam region assigned to a particular beam region. The annular regions may be considered to be of the assigned beam regions, and the features of the annular regions may not be distinguishable from the portions of the beam regions for actual use by the beam grids (desirably, so that alignment variations between different beam grids and their beam regions allow the beam grids to be projected through element 300′ without distinguishable variations or differences between the different beam grids, i.e., alignment variations may be within the tolerances allowed by the annular regions of adjacent beam regions). The annular regions may be, for example, between the outer periphery of the beam region and the outer periphery of the active portion of the beam region through which the respective beam grid passes. The annular regions of each beam grid may be considered to be a portion of the space region between the path of the beam grid and an adjacent spacer, e.g., the shortest distance between the periphery of the active portion of the beam grid and the nearest surface of the spacer, although features of the annular regions within the space region may have the features of the beam grid but not the remainder of the space region.

[0103]

[0113] For example, FIG. 9A shows three beam regions 70a-c, which may be equally spaced apart; FIG. 9B shows four beam regions 70a-d, which may be equally spaced apart from adjacent beam regions; and FIG. 9C shows six beam regions 70a-f, in which the beam regions are equally spaced apart from adjacent beam regions. There may be as many different beam regions as desired. Despite the presence of more beam regions, some features and components of element 300' may be maintained or increased to a lesser extent than the number of beam regions. That is, the number of components and features may be fewer than would be expected if multiple beam regions were achieved by having separate charged particle devices 41 with separate elements 300.

[0104]

[0114] By reducing or preventing the number of such component features corresponding to the number of beam regions (e.g., reducing the number of components and features from what would be expected if separate elements for different beam grid paths were used), multiple beam regions can be provided in a more compact area. The access area required for operation and maintenance of such a multi-device can desirably be reduced. (This assumes that the size of the beam regions is the same as if individual elements 300, or at least access areas 90, were provided for the different beam regions.) For example, access area 90 in FIG. 7 corresponds to a single beam region 70, whereas in the configurations of FIGS. 9A-9C, there is a single access area 90' for multiple beam regions, e.g., the three beam regions 70a-c in FIG. 9A. In configurations where beam region 70 in FIG. 7 is the same as beam region 80' in FIG. 9A (which need not be the case), the size of access area 90' is not significantly increased if they are not the same area (as in FIG. 9A, comparing the access area of ​​FIG. 7). Having multiple beam areas means that the total beam area, expressed as, for example, density over the total area of ​​element 300' or density per unit area of ​​the element, can be significantly larger.

[0105]

[0115] In a configuration with multiple beam regions 70a-c, such as the configuration of FIG. 9A, each beam region 70a, 70b, 70c may have the same size or area as the corresponding beam region 70 in a configuration such as that of FIG. 7 where only one beam region 70 is present. Alternatively, the beam regions 70a-c in a configuration with multiple beam regions may be a different size or area than the corresponding beam region 70 in a configuration such as that of FIG. 7 where only one beam region 70 is present. Furthermore, the multiple beam regions 70a-c may include beam regions of different sizes. In other words, there may be two or more sizes or areas of beam regions in the same charged particle device 41. It is desirable for all of the beam regions 70a-c of the multiple beam regions to be the same size or cover the same area on the element 300′.

[0106]

[0116] In one configuration, the access area 90' per beam region may be proportionally smaller as the number of beam regions present in the element 300' increases. In this manner, the total size of the access region 90' may be reduced relative to the area of ​​the sample that may be simultaneously evaluated by the device, thus increasing throughput. That is, the ratio of the area of ​​the element allocated to the access region 90' of a multi-device may be smaller for configurations having multiple beam regions, e.g., as described and illustrated with reference to FIGS. 9A-9C , and desirably, the proportional size of the access region 90' decreases as the number of beam regions increases (even though the dimensions of the element 300' (e.g., across the multi-device) may increase as the number of beam regions increases). Thus, the proportional size of the element 300 allocated to a beam region and operating on a beam of a multi-device beam grid may be larger for multiple beam regions compared to a single beam region 70, e.g., may increase as the number of beam regions increases.

[0107]

[0117] As mentioned above, in many cases, the size of an evaluation system, e.g., the area (or footprint) required to accommodate such an evaluation system in a production facility, is determined by the area required for the operation of a stage with charged particle devices of the evaluation system to scan samples. The more charged particle devices a characterization system has, the larger its area (or footprint). Due to the limited available footprint of such evaluation systems in the production facility of a chip fabrication plant, the number of charged particle devices that can be present in an evaluation system with an array of charged particle devices to scan a sample of a typical size may be limited. The present invention enables an increase in sample throughput of such evaluation systems by enabling a denser arrangement of beam regions within device 41.

[0108]

[0118] It should be noted that this discussion thus far considers the effects to be the same for all elements of the multi-device. However, the beam areas required for elements at different positions on the charged particle path from the source 201 to the sample 208, or at least to the collimators 235 (270, 271), increase in size with distance from the source. If a collimator is present, the source beam and the beam grid beams diverge. Between the collimators 235, 270, 271 and the sample, the different beams are substantially collimated. Between the surface of the device 41 facing the sample and the collimator, the beam areas may be similar, even if they are different, e.g., not the same between adjacent elements 300. Such elements may be electron-optical elements such as the collimators 235, 270, 271, the detector array 240, the lens electrode and control lens array 250 of the objective lens array 241, the scan deflectors 260, 265, and the beam-limiting aperture arrays 242, 252. Elements between the source 201 and the collimators 235, 270 may have a beam area smaller than the beam area of ​​a collimator in the same charged particle device 41. Such elements 300 that may be present between the collimator and the source may be the condenser lens array 231 and its constituent or associated beam-limiting aperture array, as well as any other elements such as correctors that may be positioned in the diverging paths of the charged particles from the source 201.

[0109]

[0119] Unlike the configuration of Figure 7, in the configuration of Figures 9A-9C, element 300' includes multiple beam regions, each beam region assigned to an individual source beam from an individual source from among multiple sources 201 as shown in the configuration of Figure 8. Element 300 is configured to operate on charged particle beams within a beam grid of individual source beams. There may be multiple elements, particularly preferably adjacent elements located directly beam upstream or beam downstream of element 300'.

[0110]

[0120] As described above, each beam region in a multi-device 41 such as that shown in FIG. 8 (i.e., in a device 41 having multiple sources 201) corresponds to an individual beam grid corresponding to a specific one of the multiple sources 201, and some other components of the device 41 are preferably shared among the different beam regions. For example, the apparatus may include a spacer 80 disposed between element 300 and an adjacent element. The spacer may include supports. The supports are preferably disposed between element 300' and an adjacent element to support the element and / or the adjacent element. For example, as shown in FIG. 9A, the spacer 80' has at least one aperture positioned to correspond to the positions of at least two beam regions, e.g., a single aperture around all beam regions 70A, 70B, and 70C, e.g., multiple beam regions. In the example of FIG. 9A, the aperture defined by the spacer 80' is positioned to surround, e.g., three beam regions 70a-c. In an alternative configuration, the aperture defined by the spacer is positioned to encompass, for example, between two and six beam regions.

[0111]

[0121] For example, as shown in FIG. 9B, the spacer can include an outer support 81 having apertures positioned to correspond to multiple beam regions 70a-d. As shown in FIG. 9B, the apertures in the outer support 81 can be positioned to correspond to or surround multiple beam regions, such as a single aperture around all four beam regions 70a, 70b, 70c, and 70d. In other words, the apertures in the spacer can surround multiple beam grids emitted by multiple, e.g., four, sources 201. In an alternative configuration, the outer support 81 can have apertures positioned to correspond to or surround more than two beam regions, e.g., two to six beam regions.

[0112]

[0122] 9B defines a circular aperture. Alternatively, the aperture defined by the outer support 81 may be non-circular, for example, rectangular, elliptical, hexagonal, or oval, or may be a shape corresponding to the beam grid enclosed by the outer support 81.

[0113]

[0123] The multiple beam regions are optionally arranged in a two-dimensional array. Desirably, the two-dimensional array has a pattern. For example, as shown in FIG. 9B, the two-dimensional array can include at least two parallel rows of beam regions, each row including at least two beam regions. Alternatively, as shown in FIG. 9C, the multiple beam regions can have a pattern including, for example, an annular portion around a central position of the beam regions. The multiple beam regions can include at least one annular portion of beam regions. For example, at least one annular portion of ring regions can be a ring of beam regions 71. The pattern can define, for example, each beam region 70b in the annular portion, equidistantly spaced from its adjacent or neighboring beam regions 70a, 70c. Hereinafter, the term "ring" will be used to describe the arrangement of beam regions as shown in FIG. 9C. However, in alternative configurations, the beam regions can be arranged around a central point. The arrangement of beam regions can be circular, forming an annular portion, particularly a ring, or non-circular, such as the three beam regions 70a-c of FIG. 9A.

[0114]

[0124] In the configuration of FIG. 9C , the ring of beam regions 71 can be positioned in an annular configuration around a central location of the multiple beam regions, such as a two-dimensional ring around the central location. The central location can be located at a midpoint between the multiple beam regions, e.g., the central location can be equidistant from each of the multiple beam regions surrounded by the outer support 81. A beam region can be equidistantly spaced from its adjacent or neighboring beam regions 70A, 70C, e.g., in an annular configuration. In other words, in both FIGS. 9B and 9C , the two-dimensional array includes beam regions arranged around a midpoint. The midpoint in these examples is at the central location of the multiple beam regions. For example, in the configuration of FIG. 9C , the two-dimensional array is an annular configuration of beam regions, and the annular configuration forms the ring of beam regions 71.

[0115]

[0125] For example, as shown in FIGS. 9B and 9C, the spacer optionally includes an inner support 82 disposed between the element 300′ and an adjacent element to support the element and / or adjacent elements. The periphery of the inner support 82 is surrounded by three or more beam regions. In an embodiment such as that shown in FIG. 9B, the inner support 82 is surrounded by four beam regions. In an embodiment such as that shown in FIG. 9C, the inner support 82 is surrounded by six beam regions 70a-f. In the configurations of FIGS. 9B and 9C, the inner support 82 may be positioned at a central location at the midpoint of multiple beam regions. There may be two or more inner supports, one of which may be positioned at the central location; in a different configuration, all central supports are positioned away from the central location, preferably within the outer support 81.

[0116]

[0126] The inner support 82 desirably provides sufficient support for the element 300′ to allow the beam regions (or regions of adjacent elements defining adjacent beam regions) to be spaced apart so that the outer support 81 defines an aperture having a diameter larger than that of the configuration of FIG. 9A . In a configuration such as that shown by FIG. 9A , there is a single support, the outer support 81. Thus, the outer support 81 supports the element 300′ and / or adjacent elements such that the gap between the element and the adjacent element is maintained, for example, above a threshold distance, i.e., the space (e.g., defined by the gap) between the element and the adjacent element is maintained above or at a threshold distance, for example, in intermediate regions of the space, element, and / or adjacent element. Therefore, the gap is not excessively reduced in the intermediate regions, which could pose a risk of discharge. In a configuration such as that shown and described with reference to FIG. 9A , the diameter of the aperture defined by the outer support 81 can have a threshold diameter that defines a maximum allowable diameter. This may mean that the aperture diameter cannot exceed a threshold diameter above that of element 300', otherwise the element and adjacent elements will not have sufficient support and a high risk of discharge, for example, in the intermediate region. Thus, beam regions 70a-c in the configuration of FIG. 9A are spaced closer together compared to beam regions 70a-d in the configuration of FIG. 9B. In the configuration of FIG. 9B, inner support 82 supports element 300' in the intermediate region, e.g., equidistant from the surrounding beam regions. Thus, the aperture diameter of outer support 81 may be larger than the aperture of a spacer enclosing fewer beam regions, e.g., enclosing four beam regions as shown and described with reference to FIG. 9B, but having three beam regions as shown in FIG. 9A.

[0117]

[0127] Optionally, in an alternative configuration, the inner support may have one or more apertures defined therein. Such apertures may be positioned to correspond to or surround one or more beam regions. For example, the multiple beam regions may include a central beam region, e.g., for each aperture, positioned, e.g., in a mid-region of the element. The central beam region is desirably located in a central position. The central beam region is optionally surrounded by the inner support. Such an inner support may have the same features as those described with respect to outer support 81, as shown in and described with reference to FIGS. 7 and 9A-9C.

[0118]

[0128] In this configuration, the multi-device 41 may include elements 300' as shown in and described with reference to FIGS. 9A-9C, and may include multiple sub-devices 42. The number of sub-devices 42 in the charged particle multi-device 41 can be used to simultaneously scan samples, such as samples with an industry-standard size, e.g., 300 mm in diameter, to provide coverage of many charged particle beams on the sample surface. The time required for such a multi-device 41 can be reduced compared to using, for example, multiple charged particle devices 41 with a single source and a single beam region, rather than a source array with multiple beam regions. Currently, there is a limit to the beam current that can be generated with a single power supply. Using multiple power supplies allows for increased beam current without increasing the beam current per power supply. Furthermore, compared to scanning a sample with a charged particle device 41 using only one source, the sample area scanned per unit time by the multi-source 41 is larger. That is, the surface area of ​​a standard sample is scanned in a shorter time. The throughput of the multi-device 41 is therefore greater than that of known devices with a single source. Thus, including multiple beam regions per device 41 (e.g., as a multi-device) may reduce costs by reducing the total number of devices used per sample. Furthermore, the multi-source generation of beam regions with a greater density than known multi-device designs allows such multi-devices to have a greater percentage of their cross-section as beam regions, potentially allowing faster scanning of sample surfaces with such multi-devices for greater throughput. A higher density of multiple beam regions per multi-device 41 may further reduce the scan time required per sample, e.g., cost of goods.

[0119]

[0129] Within the inner support, there may be one or more additional inner supports, which may have the same characteristics as the inner support shown and described with reference to Figures 9B-9C. The outer support 81, inner support 82, and additional inner supports may be referred to as a support arrangement, such as a concentric support arrangement. Such a concentric support arrangement may have as many support elements as necessary, for example, there may be at least two concentric elements with a common axis at a central location. However, it may be desirable for the support arrangement to have several support elements, for example, to optimize, and preferably maximize, the proportional size of the beam area relative to the elements.

[0120]

[0130] Another alternative exemplary configuration is shown in FIG. 10. The configuration of FIG. 10 includes multiple beam regions 70'', spacers, and access portions 90''. Similar to the configuration of FIG. 9C, there is at least one annular portion of beam regions, illustrated as a ring of beam regions. The configuration of FIG. 10 includes an inner annular portion of beam regions 72 (or inner ring) disposed adjacent a central location. The inner ring of beam regions 72 of FIG. 10 includes six beam regions. In alternative configurations, the inner ring may include one to six beam regions.

[0121]

[0131] The configuration of FIG. 10 further includes an outer ring of beam regions 73. The outer ring of beam regions 73 surrounds the inner ring of beam regions 72. The outer ring of beam regions 73 is positioned concentrically around the inner ring of beam regions 72. In the configuration of FIG. 10, the outer ring of beam regions includes 19 beam regions. In alternative configurations, the outer ring can include any number of beam regions, e.g., more than the number of beam regions in the inner ring 72, e.g., 6 to 20 beam regions. Further, alternative configurations can optionally include multiple rings, such as one or more additional rings of beam regions. The additional rings can be concentrically positioned around the outer ring, such that the outer ring can be between the inner and additional rings. For example, in one configuration, there can be up to four rings, including an inner ring with up to six beam regions, and the outer ring can have up to 20 beam regions, and there can be two additional rings with, e.g., up to 33 and up to 46 beam regions, respectively. Multiple rings can be positioned over a sample having a diameter of 300 mm. A charged particle device 41 (or multi-device) may have more than 100 sources 201 (e.g., up to 105 sources 201), and therefore, for example, there may be more than 100 subdevices 42. It should be noted that different sources 201 may emit charged particles that impinge on the sample with a beam grid having a corresponding beam area 75, and that in parts of the subdevice 42 with diverging charged particles, the beam area may be smaller. Multiple beam areas of the beam grids of different subdevices 42 may be provided on a single sample, for example, the subdevices may be configured to scan the sample, desirably simultaneously.

[0122]

[0132] In the configuration of FIG. 10 , the spacer further includes an intermediate support 83 disposed between the element and adjacent elements to support the element and / or adjacent elements. Specifically, in the configuration of FIG. 10 , the intermediate support 83 is configured to surround the inner ring 72 of the beam region. The intermediate support 83 is surrounded by the outer ring 73 of the beam region. The configuration of FIG. 10 also includes an outer support 84 configured to surround the beam region of the outer ring 73. In alternative configurations, the outer support may not be included because the intermediate support provides sufficient support to the element and adjacent elements so that the element and adjacent elements can be fully supported. Furthermore, for example, as shown in FIG. 10 , the spacer may include an inner support 82 disposed in an intermediate region, more preferably in a central location.

[0123]

[0133] In the configuration of FIG. 10 , the intermediate support 83 defines one of the at least one apertures defined by the spacer. The intermediate support 83 is positioned to correspond to the inner ring 72 of the beam region 70″. In an alternative configuration, the intermediate support may have a continuous surface without an aperture. The intermediate support may be positioned between at least one beam region of the inner ring 72 of the beam region and at least one beam region of the outer ring 73 of the beam region. The intermediate support may include multiple separate support structures disposed around the inner ring of the beam region. In this manner, the intermediate support provides support for elements between the inner ring 72 and the outer ring 73.

[0124]

[0134] The intermediate support is optionally positioned between two adjacent beam regions, for example, equidistant between the two or more beam regions. Desirably, the location of the intermediate support corresponds to the intermediate region. Desirably, the intermediate support surrounds one or more of the beam regions. The intermediate support may define one or more apertures. For example, the intermediate support may define multiple apertures. Each aperture of the intermediate support may correspond to or surround at least one beam region. Desirably, each aperture of the intermediate support may surround two or more adjacent beam regions.

[0125]

[0135] The elements are preferably configured to be positioned such that the array of apertures is disposed along the path of the beam grid. The elements 300, 300' may be, for example, electrodes of a lens array. The electrodes are preferably electrode plates. The lens array optionally includes adjacent elements and spacers.

[0126]

[0136] 9A-9C and 10 are shown as being continuous and surrounding the multiple beam regions. Instead of being continuous, the spacers may be multiple separate support structures positioned at locations around the multiple beam regions.

[0127]

[0137] Each configuration of beam regions as shown in Figures 9A-9C and 10 corresponds to a different charged particle subdevice 42 having a different number of sources 201. The number of beam regions may correspond to the number of subdevices 42. In particular, the charged particle device 41 associated with Figure 9A comprises three sources 201, while the charged particle device 41 associated with Figure 9B comprises four sources 201 and the charged particle device 41 associated with Figure 9C comprises six sources 201. The charged particle device 41 associated with Figure 10 comprises 25 sources 201.

[0128]

[0138] Having densely arranged beam regions within the multi-device 41 allows, for example, multiple multi-devices 41 of the same design to be scanned over a sample. Such a configuration can increase throughput. For example, up to seven charged particle devices 41 having the multiple beam region arrangement shown in FIG. 9A can be positioned facing a single sample having a standard diameter of, for example, 300 mm. Desirably, the charged particle device 41 is configured so that multiple beams of the beam grid are configured to scan the sample simultaneously. In this way, a total of up to 21 beam regions can be provided simultaneously over the same sample.

[0129]

[0139] In a configuration of up to seven charged particle devices 41 having the multiple beam field arrangement shown in and described with reference to FIG. 9B , they can be positioned facing a single sample having a diameter of 300 mm, preferably with the charged particle devices 41 configured so that multiple beams of the beam grid are configured to scan the sample simultaneously. In this manner, a total of up to 28 beam fields can be provided simultaneously on the same sample. In a configuration of up to seven charged particle devices 41 having the beam field arrangement shown in FIG. 9B , they can be positioned facing a single sample having a diameter of 300 mm, preferably with the charged particle devices 41 configured so that multiple beams of the beam grid are configured to scan the sample simultaneously. In this manner, a total of up to 42 beam fields can be provided simultaneously on the same sample.

[0130]

[0140] A similar configuration can be applied to the multi-device 41 shown in and described with reference to Figures 9C and 10.

[0131]

[0141] The elements 300, 300′ and any corresponding adjacent elements (or adjacent elements opposite the elements) are included in a lens array. The lens array may be a condenser lens array, which may correspond to the array of condenser lenses 231 as described above with reference to FIG. 3, for example. The charged particle device 41 may include multiple condenser lens arrays, each including the elements 300′, as described above with reference to FIGS. 9 and 10. The one or more condenser lens arrays are preferably configured to generate multiple beams of the beam grid from individual source beams. Alternatively or additionally, the lens array may be an objective lens array, which may correspond to the objective lens array 241 as described above with reference to FIG. 3, for example. The charged particle device 41 may include multiple objective lens arrays, each including the elements 300′, as described above with reference to FIGS. 9 and 10. The one or more objective lens arrays are preferably configured to operate on multiple beams of the beam grid.

[0132]

[0142] One configuration may include one or more condenser lens arrays and one or more objective lens arrays. Each of the lens arrays may include elements 300'. Such objective lens arrays are desirably positioned downstream in the beam from the condenser lens arrays. In this manner, one or more condenser lens arrays are positioned upstream in the beam from one or more objective lens arrays. One or more objective lens arrays are positioned downstream in the beam from one or more condenser lens arrays.

[0133]

[0143] At least one of the one or more condenser lens arrays desirably has two or more of the multiple beam regions. For example, the charged particle device 41 may include a single condenser lens array. Thus, multiple beam grids may form beam regions on the same condenser lens array. In an alternative configuration, there may be multiple condenser lens arrays, each including, for example, different elements 300', and each condenser lens array may be arranged so that multiple beam regions correspond to each condenser lens array.

[0134]

[0144] Similar to one or more condenser lens arrays, the charged particle device 41 (or multi-device 41) may additionally or alternatively include one or more objective lens arrays. At least one of the one or more objective lens arrays desirably has two or more of the multiple beam regions. For example, the charged particle device 41 may include a single objective lens array. Thus, multiple beam grids may form beam regions on the same objective lens array. In an alternative configuration, there may be multiple objective lens arrays, each arranged such that multiple beam regions correspond to each objective lens array.

[0135]

[0145] The one or more lens arrays optionally include more condenser lens arrays than objective lens arrays. Desirably, the beam area per objective lens array is, on average, greater than the beam area per condenser lens array. For example, there may be multiple condenser lens arrays and a single objective lens array. The number of condenser lens arrays may optionally correspond to the number of sources. Alternatively, there may be the same number of beam areas per objective lens array as there are beam areas per condenser lens array. With this configuration, desirably, each objective lens array has the same number of beam areas as the corresponding condenser lens array assigned to the same source beam. For example, each objective lens array may be positioned directly beam downstream of the corresponding condenser lens array.

[0136]

[0146] In at least one of the one or more lens arrays, the aperture array defines at least one pattern. The pattern may be present as a patterned array, such as a two-dimensional array of apertures, in one or more of the elements 300′ included in the one or more lens arrays. The aperture pattern may have apertures positioned over the beam regions provided by at least one or more elements. For example, in at least one of the lens arrays, the aperture array may define a single continuous pattern, such as a continuous pattern of a two-dimensional array of apertures. In particular, in at least one of the one or more lens arrays, the distance between apertures of the aperture array in two different, adjacent beam regions may be the same as the distance between adjacent apertures in the two different beam regions. In this way, there may be no pattern discontinuity between different beam regions of the lens array, i.e., the pattern of apertures defining the beam regions may be continuous, for example, between and including the beam regions.

[0137]

[0147] Alternatively, there may be multiple patterns. The multiple patterns may be multiple occurrences of the same pattern. Alternatively, the multiple patterns may include two or more distinct patterns that are different from each other. The multiple patterns may be discontinuous with each other, such that the distance between adjacent apertures within the same pattern is shorter than the distance between apertures in adjacent patterns. Each of the multiple patterns may correspond to a respective beam region. For example, in at least one of the one or more lens arrays, the distance between adjacent apertures from different, adjacent beam regions may be different from the distance between apertures in the respective beam region. In particular, in at least one of the one or more lens arrays, the distance between apertures in the aperture array in two different, adjacent beam regions may be different from the distance between adjacent apertures in the two different beam regions. Alternatively, the patterns may be distinct due to differences in aperture placement instead of, or in addition to, being distinct because the patterns are spaced apart from each other. Desirably, the aperture array of one or more condenser lens arrays includes more beam region arrays of discontinuous patterns than the number of discontinuous patterns in the aperture array of the objective lens array.

[0138]

[0148] The one or more lens arrays preferably include a plurality of lens arrays including at least two groups of lens arrays. Each group of lens arrays includes one or more lens arrays of the plurality of lens arrays. For example, the plurality of lens arrays may include one or more condenser lens arrays, where the one or more condenser lens arrays may form one group of lens arrays. The plurality of lens arrays may include one or more objective lens arrays, where the one or more objective lens arrays may form another group of lens arrays. The same may apply to collimating lens arrays and / or control lens arrays.

[0139]

[0149] Preferably, each group of the lens arrays is configured to be individually controlled. In particular, at least one group of the lens arrays may be configured to be actuated relative to at least another group of the lens arrays in at least one degree of freedom. Preferably, at least one of the one or more lens arrays is configured to be actuated in up to six degrees of freedom. This preferably allows the groups of lens arrays to be aligned relative to each other.

[0140]

[0150] At least one group of lens arrays includes at least one lens array having multiple beam regions. The multiple beam regions optionally correspond to one ring of the beam region, e.g., inner ring 72 in the configuration of FIG. 10 . Another group of lenses may include at least one lens array having multiple beam regions corresponding to another ring of the beam region, e.g., outer ring 73 in the configuration of FIG. 10 . In this manner, it may be possible to independently align different lens arrays corresponding to different rings of the beam region. In this manner, an actuator configured to actuate the lens arrays may be shared between groups of lens arrays. Alternatively, each lens array may have its own actuator so that each lens array is individually controllable, although this configuration may be more complex and require a larger access area compared to a configuration in which only each group of lens arrays has a corresponding actuator, e.g., a single actuator.

[0141]

[0151] 9 and 10 , elements 300′, including, for example, spacers and / or lens arrays of a charged particle device 41 (or multi-device), may be shared among multiple sources 201, instead of each source 201 being associated with a dedicated element 300′, such as a spacer and / or lens array, that interacts only with the beam grid of the corresponding source 201. That is, some, if not all, sources may share a multi-device 41. Such elements may be shared among one or more of multiple sub-devices 42 of a multi-device 41, and each source 201 may be associated with a different sub-device 42. Furthermore, in addition to or instead of elements 300′, spacers, and / or lens arrays being shared among multiple sources of a charged particle device, other components of a multi-device 41 may be shared.

[0142]

[0152] FIG. 11 provides a side view (e.g., a cross section in the direction of the beam path or electron optical axis) of a charged particle apparatus including a charged particle device 41 (or multiple devices 41). As an exemplary configuration, the charged particle device 41 of FIG. 11 provides an arrangement of four beam regions arranged in two rows of two beam regions, similar to the arrangement of beam regions shown in FIG. 9B. The charged particle device 41 of FIG. 11 includes multiple charged particle beam sources 201. The charged particle device 41 of FIG. 11 includes four sources 201 (two of which are visible), a collimator 235, a condenser lens array 231, and an objective lens array 241. The collimator is configured to collimate the beams of the beam grid from the diverging array of beams from the condenser lens array 231 into collimated beams, for example, toward a sample. As mentioned above, with reference to FIGS. 8-10, the objective lens array 231 and / or the objective lens array 241 can be formed from one or more elements 300′. Additionally, any other elements such as the detector 240 (which may be associated with the illustrated objective lens array 241), the collimator array 235, the control lens array (which may be associated with the objective lens array), the scan deflector array 235, and the correction array may each include one or more elements 300'.

[0143]

[0153] As indicated by arrows 601, 602 in FIG. 11 , one or more of the collimator 235, the condenser lens array 231, and the objective lens array 241 can be actuated in one or more directions. In principle, any of the elements, or a charged particle device comprising multiple elements 300, 300′, can be actuated in one or more directions. For example, one or more of the collimator 235, the condenser lens array 231, and the objective lens array 241 can be actuated in one or more translational directions and / or one or more rotational directions. In particular, one or more of the collimator 235, the condenser lens array 231, and the objective lens array 241 can be actuated in a Z direction 602 in FIG. 11 , which can correspond to the direction of charged particle flow from the source 201 to the sample, which can be vertical. Additionally or alternatively, one or more of the collimator 235, the condenser lens array 231, and the objective lens array 241 may be actuated in an X direction 601 in Figure 11, which may be a lateral direction orthogonal to the Z direction, which may be a horizontal direction. Additionally or alternatively, one or more of the collimator 235, the condenser lens array 231, and the objective lens array 241 may be actuated in a Y direction, which may be a lateral direction orthogonal to the X and Z directions, and in some cases a horizontal direction. Different electron-optical devices may be actuated to rotate around any of different axial directions of a reference frame, for example around the X, Y, and / or Z directions.

[0144]

[0154] Additionally, one or more elements 300′ may form a collimator 235. The collimator 235 is preferably configured to operate on beams associated with different beam regions and / or beam grids. In other words, the collimator 235 may be positioned such that the collimator 235 is in the path of a beam grid from multiple sources 201. Similarly, the element 300′ and / or adjacent elements may include a detector array, such that an element associated with the detector array has multiple beam regions. The detector array preferably includes a detector element associated with each aperture. The detector array is preferably configured such that the detector elements are positioned such that they are associated proximate to, for example, the objective lens array. In one embodiment, the detector array is preferably configured such that the detector elements are positioned such that they face a sample location where a sample is placed during use.

[0145]

[0155] The charged particle device of FIG. 11 further includes a cooling conduit 402 configured to thermally condition the lens array. The cooling conduit may be a path or conduit for a coolant, such as a fluid such as water, that can be thermally conditioned to have a stable temperature. The coolant may have a high heat capacity, allowing for efficient thermal conditioning. In an alternative configuration, one or more cooling conduits may be provided to thermally condition any element and / or adjacent elements within the charged particle device. In such a configuration, the cooling conduit desirably contacts the element and / or adjacent elements. For example, the cooling conduit may be provided along a surface of the element, e.g., away from the beam region, and the element and / or adjacent elements may be composed of a material with a high heat capacity. Desirably, the cooling conduit includes at least one path between different beam regions.

[0146]

[0156] The charged particle device 41 may be provided within a vacuum chamber. The charged particle device and the vacuum chamber may form components of a charged particle apparatus. In particular, a charged particle device such as the multi-device 41 is desirably housed entirely within the vacuum chamber. In this manner, multiple sub-devices 42 may be arranged within the same common vacuum chamber, e.g., a wall 500 that may be continuous, e.g., enclosing the charged particle device 41 to maintain a low pressure within the vacuum chamber. In one configuration, the vacuum chamber may include an actuation stage and, optionally, a support 209 for supporting the sample 208. A vacuum system including a vacuum pump may be used to maintain the vacuum within the vacuum chamber. A vacuum port 406 may be provided through the wall 500 of the vacuum chamber. The vacuum port may be connected to the vacuum pump of the vacuum system.

[0147]

[0157] This may be a simpler and more efficient configuration than alternatives in which each device has a dedicated single source and vacuum chamber. The common, or shared, vacuum chamber optionally includes at least one cooling port 403, as shown in FIG. 11 . While three are shown, there may be as many or as few as needed, e.g., one. The device may include multiple vacuum subchambers, with each source 201 desirably housed within its own vacuum subchamber. The cooling port may be shared between different subchambers so that the subchambers can be efficiently cooled and the device does not become overly complex. The cooling port 403 may be a feedthrough through the wall of the vacuum chamber for passage of cooling conduits 402, which poses less risk to the integrity of the vacuum chamber, or a fluid supply to the cooling conduits within the chamber.

[0148]

[0158] For example, as shown in Figure 11, the charged particle device 41 may further include a shield 405 configured to extend at least partially between the paths of different beam grids. As shown in Figure 11, the shield 405 may be positioned between the paths of two or more beam grids such that the beam paths of the two or more beam grids share the shield 405. In this way, shielding within the device is efficiently used between different beam grids associated with corresponding sources 201. In an alternative configuration, the shield may extend along a grid path whose beam regions have a discontinuous pattern.

[0149]

[0159] For example, as shown in FIG. 11, the sources 201 include emitters, and the apparatus further includes shields 405 at least between the emitters of different sources, eg, between different sources 201.

[0150]

[0160] In the charged particle device 41 described above with reference to FIGS. 8-11, a voltage supplier 401 can be configured to apply a potential to the element and / or adjacent elements. The applied potential can be any potential within the operating range of the charged particle multi-device. For example, the voltage supplier can connect the element to ground. Desirably, the voltage supplier applies potentials to different sources, e.g., at different high potentials relative to ground or the sample. As shown in FIG. 11, voltages can be supplied by the voltage supplier 401 to the source 201 to emit charged particles to generate different beam grids for operation with different beam regions of the element.

[0151]

[0161] The voltage supplier 401 may apply a potential difference between an element and an adjacent element. In this way, a potential difference may be applied between adjacent beam regions of different elements, for example, an element and an adjacent element, to supply a high potential voltage to one or more elements of the device 41. The voltage supplier 401 may apply a potential to one or more elements of a lens array, such as the condenser lens array 231 and / or the objective lens array 241. The voltage supplier 401 may be provided to operate on such elements associated with multiple beam regions.

[0152]

[0162] The charged particle device may include electronics associated with the element and / or adjacent elements. Each element and / or adjacent element and its corresponding electronics are preferably associated with two or more beam regions. For example, the element and / or further elements may include an electrode array configured to be controlled by the electronics. In configurations in which at least one of the element and adjacent elements is a detector, the electronics may additionally be capable of receiving, processing, and / or transmitting directional signals from the detector to a process external to the charged particle device or evaluation system. All or a portion of the electronics is optionally located remotely from the element and / or adjacent elements. For example, the electronics may be located outside the vacuum chamber. Alternatively or additionally, all or a portion of the electronics may be included on or adjacent to the element and / or adjacent elements.

[0153]

[0163] There may be one or more feedthroughs in the chamber wall that allow services such as power, e.g., electricity, signals (optical and / or electronic), and coolant through the chamber wall while maintaining a vacuum within the vacuum chamber. The charged particle device may further comprise such feedthroughs 404 configured to pass electrical connections of a voltage supply 401 to apply an electrical potential, e.g., a high potential, to one or more elements of the device 41. Thus, the feedthroughs are used more efficiently than in an alternative configuration in which different feedthroughs are associated with a single beam region of different elements 300′ of a corresponding single source.

[0154]

[0164] Similarly, the charged particle device may further comprise a feedthrough 404 configured to transmit, control, and receive detection signals to and from the device 41; for example, the feedthrough 404 may be configured to pass signal conductors, for example, to and from a vacuum chamber with one or more elements of the charged particle multi-device 41. The feedthrough 404 may be the same as that used to supply voltage, or may be a different, additional feedthrough. The feedthrough 404 (which may be one feedthrough for all sources, or one or more feedthroughs each for a different source or group of sources) may be configured for passing electrical connections from the voltage supplier 401 to the sources 201, such as emitters.

[0155]

[0165] The same feedthrough 404 may be used for passing control signals, detection signals, and / or power, for example, to set the potential of a source and / or element through the vacuum chamber wall 500. Thus, one or more of the cooling ports 403 through the vacuum chamber wall 500 is effectively a feedthrough. In one configuration, the cooling conduit 402 is contained within the same feedthrough 404, 403 for control signals, detection, and / or power supply. While having individual feedthroughs for different functions may help simplify the layout of service lines (e.g., cable fibers and tubing) within the chamber, which may aid in layout within the vacuum chamber and help maintain a desirably small size of the vacuum chamber, it may be preferable to pool (or combine) functions into fewer feedthroughs, preferably one. Having a smaller number of feedthroughs may help reduce the risk of vacuum breakdown. Such a feedthrough suitable for multiple functions (e.g., of cables, wires, pipes, and other features for transmitting electrical signals, such as PCBs) for a service line is shown in WO 2018121969, which claims a priority date of December 27, 2016, and is incorporated herein by reference with respect to at least the portions relating to the features of the feedthrough and the method of feedthrough through the service line.

[0156]

[0166] The following provisions are provided:

[0157]

[0167] Clause 1. A charged particle device for projecting multiple beams of charged particles toward a sample, comprising: a plurality of sources configured to emit respective source beams of charged particles along respective paths of a beam grid toward the sample, the beam grid including a plurality of charged particle beams; and one or more elements defining an array of apertures each including a plurality of beam regions assigned to a respective source beam, the one or more elements configured to operate on the charged particle beams in the beam grid of the respective source beam, each element being separated from an adjacent element by a spacer, the spacer having at least one aperture positioned to correspond to the position of at least two of the beam regions.

[0158]

[0168] Clause 2. The device of clause 1, wherein one or more elements are configured to be positioned such that the array of apertures is disposed along the path of the beam grid.

[0159]

[0169] Clause 3. A device according to clause 1 or 2, wherein each beam region corresponds to an individual beam grid of one of the individual source beams.

[0160]

[0170] Clause 4. A device according to any one of the preceding clauses, wherein the elements are electrodes of a lens array, preferably the electrodes are electrode plates, and preferably the lens array includes adjacent elements and spacers.

[0161]

[0171] Clause 5. A device according to any one of the preceding clauses, wherein the spacer includes an outer support disposed between adjacent elements for supporting the adjacent elements.

[0162]

[0172] Clause 6. A device as described in Clause 5, wherein the outer support defines at least one aperture, preferably the aperture is positioned to correspond to the positions of the multiple beam regions, and preferably the outer support is positioned to surround the multiple beam regions.

[0163]

[0173] Clause 7. A device described in any one of the preceding clauses, wherein the plurality of beam regions are preferably arranged in a two-dimensional array having a pattern, the two-dimensional array preferably including at least two parallel rows of beam regions, each row including at least two beam regions.

[0164]

[0174] Clause 8. The device of clause 7, wherein the plurality of beam regions includes at least one ring of beam regions arranged in a two-dimensional ring around a central location at a midpoint of the plurality of beam regions, and preferably the at least one ring of beam regions includes up to four rings of beam regions.

[0165]

[0175] Clause 9. A device as described in Clause 7, wherein the two-dimensional array includes beam regions arranged around an intermediate region, preferably at a central position, of a plurality of beam regions, and preferably the two-dimensional array is an annular portion, such as an annular portion, of beam regions, and preferably the annular portion forms at least one ring.

[0166]

[0176] Clause 10. A device as described in clause 8 or 9, wherein at least one ring of beam regions includes an inner ring of beam regions positioned adjacent a central position, and preferably the inner ring of beam regions includes up to six beam regions.

[0167]

[0177] Clause 11. A device as described in Clause 10, wherein at least one ring of beam regions includes an outer ring of beam regions, the outer ring of beam regions surrounding an inner ring of beam regions, preferably the outer ring of beam regions being positioned concentrically around the inner ring of beam regions, preferably the outer ring of beam regions including up to 20 beam regions.

[0168]

[0178] Clause 12. A device described in any one of the preceding clauses, wherein the spacer includes an intermediate support positioned between adjacent elements to support the adjacent elements, the intermediate support being positioned equidistant between two adjacent beam regions, for example between two or more beam regions, preferably the position of the intermediate support corresponds to the intermediate region, preferably the intermediate support surrounds, for example, one or more of the beam regions and is positioned around the intermediate region, for example the spacer may have a plurality of apertures defined therein, the intermediate support may define one or more apertures therethrough.

[0169]

[0179] Clause 13. A device as described in Clause 11, wherein the spacer includes an intermediate support disposed between adjacent elements to support the adjacent elements, the intermediate support being positioned between at least one beam region of the inner ring of the beam regions and at least one beam region of the outer ring of the beam regions, preferably the intermediate support surrounding the inner ring of the beam regions and the intermediate support being surrounded by the outer ring of the beam regions, preferably the intermediate support defining one of the at least one aperture, the intermediate support being positioned to correspond to the inner ring of the beam regions.

[0170]

[0180] Clause 14. A device described in any one of clauses 8 to 13, wherein the plurality of beam regions includes a central beam region positioned within the intermediate region, preferably at a central location.

[0171]

[0181] Clause 15. A device described in any one of the preceding clauses, wherein the spacer includes an inner support positioned between adjacent elements to support the adjacent elements, the periphery of the inner support being surrounded by three or more beam regions, and preferably the inner support being positioned at a central position at the midpoint of the multiple beam regions.

[0172]

[0182] Clause 16. A device according to any one of clauses 4 to 15, wherein the one or more lens arrays comprise one or more condenser lens arrays.

[0173]

[0183] Clause 17. The device of clause 11, wherein one or more condenser lens arrays are configured to generate a plurality of beams of the beam grid from individual source beams.

[0174]

[0184] Clause 18. A device described in any one of clauses 4 to 15, wherein the one or more lens arrays include one or more objective lens arrays configured to operate on a plurality of beams of the beam grid.

[0175]

[0185] Clause 19. A device according to clause 16 or 17, wherein the one or more lens arrays comprise one or more objective lens arrays configured to operate on a plurality of beams of the beam grid.

[0176]

[0186] Clause 20. A device according to clause 18 or 19, wherein one of the objective lens arrays has two or more of the plurality of beam regions.

[0177]

[0187] Clause 21. A device according to clause 19 or 20, wherein the one or more lens arrays include a greater number of condenser lens arrays than objective lens arrays, and preferably the aperture arrays of the condenser lens arrays include a greater number of discontinuous patterns than the objective lens arrays.

[0178]

[0188] Clause 22. A device according to any one of clauses 19 to 21, wherein the beam area per objective lens array is on average greater than the beam area per condenser lens array.

[0179]

[0189] Clause 23. A device as described in clause 19 or 20, wherein there are the same number of beam areas per objective lens array as there are beam areas per condenser lens array, and preferably each objective lens array has the same number of beam areas as the corresponding condenser lens array assigned to the same source beam.

[0180]

[0190] Clause 24. A device according to any one of clauses 16 to 23, wherein in at least one of the one or more lens arrays, the pattern of the aperture arrays for different beam regions within the array is the same.

[0181]

[0191] Clause 25. A device according to any one of clauses 16 to 24, wherein in at least one of the one or more lens arrays, the distance between adjacent apertures in the beam region is the same.

[0182]

[0192] Clause 26. A device described in any one of clauses 16 to 25, wherein in at least one of the one or more lens arrays, the distance between adjacent apertures from different, adjacent beam regions is different from the distance between apertures within the respective beam regions.

[0183]

[0193] Clause 27. A device described in any one of clauses 16 to 26, wherein at least one of the one or more lens arrays includes apertures for different beam regions and has a discontinuous pattern between the different beam regions.

[0184]

[0194] Clause 28. A device described in any one of clauses 16 to 27, wherein in at least one of the one or more lens arrays, the distance between apertures in two different, adjacent beam regions is the same as the distance between adjacent apertures in the two different beam regions, and the apertures in the different beam regions have a continuous pattern.

[0185]

[0195] Clause 29. A device according to any one of the preceding clauses, wherein the one or more lens arrays comprise a plurality of lens arrays comprising at least two groups of lens arrays, each group of lens arrays comprising one or more lens arrays of the plurality of lens arrays, and each group of lens arrays configured to be individually controlled.

[0186]

[0196] Clause 30. A device as described in clause 29, wherein at least one group of the lens arrays is configured to be actuated relative to at least another group of the lens arrays in at least one degree of freedom, and preferably at least one of the one or more lens arrays is configured to be actuated in up to six degrees of freedom.

[0187]

[0197] Clause 31. A device as described in Clause 30, wherein at least one of the groups of lens arrays includes a plurality of lens arrays, and preferably at least one of the groups of lens arrays includes a lens array having a plurality of beam areas corresponding to rings of beam areas.

[0188]

[0198] Clause 32. A device as described in clause 29 or 30, wherein the at least two groups of lens arrays include at least one group of condenser lens arrays and at least one group of objective lens arrays, and preferably the number of groups of condenser lens arrays is different from the number of groups of objective lens arrays.

[0189]

[0199] Clause 33. A device according to any one of the preceding clauses, wherein voltages are applied to the aperture array and / or adjacent elements to provide voltages to different beam regions.

[0190]

[0200] Clause 34. The device of clause 33, further comprising a voltage supplier configured to supply a voltage.

[0191]

[0201] Clause 35. A device according to any one of the preceding clauses, wherein the element or adjacent elements preferably comprises a detector array including a detector element associated with each aperture, preferably the detectors being configured to face the sample position.

[0192]

[0202] Clause 36. A device according to any one of the preceding clauses, further comprising a cooling conduit configured to thermally condition the element and / or adjacent elements, preferably the cooling conduit being in contact with the element and / or adjacent elements, for example along a surface of the element, preferably the cooling conduit comprising a path between different beam regions, preferably having a discontinuous pattern.

[0193]

[0203] Clause 37. A device according to any one of the preceding clauses, wherein associated with the element and / or adjacent elements is electronics associated with two or more beam regions, and preferably the element and / or further elements comprise an electrode array configured to be controlled by the electronics, for example the electronics may be remote from the element and / or adjacent elements and / or may be included in the element and / or adjacent elements.

[0194]

[0204] Clause 38. A device according to any one of the preceding clauses, wherein the plurality of elements includes a collimator configured to collimate beams of the beam grid, preferably from diverging paths, and preferably the collimator operates on beams associated with different beam regions and / or beam grids.

[0195]

[0205] Clause 39. A device as described in any one of the preceding clauses, further comprising a shield, preferably configured to extend at least partially between paths of different beam grids so that the beam paths share the shield along part of the path of the beam grid, for example along a grid path in which the beam areas have a discontinuous pattern.

[0196]

[0206] Clause 40. A device according to any one of the preceding clauses, wherein the source comprises emitters, and the apparatus further comprises a shield between the emitters.

[0197]

[0207] Clause 41. A charged particle apparatus for projecting multiple beams of charged particles towards a sample, the charged particle apparatus comprising a device according to any one of the preceding clauses and a stage configured to support the sample.

[0198]

[0208] Clause 42. The apparatus of clause 41, further comprising a vacuum chamber, wherein the device is housed within the vacuum chamber, and preferably the vacuum chamber includes at least one cooling port.

[0199]

[0209] Clause 43. The apparatus of clause 42, further comprising a plurality of vacuum sub-chambers, preferably each source being housed within a respective vacuum sub-chamber.

[0200]

[0210] Clause 44. Apparatus according to any one of clauses 41 to 43, further comprising a feedthrough configured to supply a voltage of elevated potential to one or more elements of the device, preferably a feedthrough for supplying a voltage to be applied to one or more elements of the device, such elements operating over two or more of the beam regions.

[0201]

[0211] Clause 45. An apparatus as described in any one of clauses 41 to 44, further comprising a feedthrough configured to transmit control signals to the device, preferably one or more elements of the device, and to receive detection signals from one or more elements of the device, such elements operating over two or more of the beam regions.

[0202]

[0212] References to a component or system of components or elements being controllable to manipulate a charged particle beam in a particular manner include configuring a controller or control system or control unit to control the component to manipulate the charged particle beam in the described manner, and optionally using other controllers or devices (e.g., voltage and current supplies) to control the component to manipulate the charged particle beam in this manner. For example, a voltage supply may be electrically connected to and apply an electrical potential to one or more components, such as element 300′ of each component, a non-limiting list of which includes control lens array 250, objective lens array 241, condenser lens 231, corrector, collimator element array, and scan deflector array 260, all under the control of a controller or control system or control unit. An actuatable component, such as a stage, may be controllable to actuate and thus move relative to another component, such as the beam path, using one or more controllers, control systems, or control units to control the actuation of the component.

[0203]

[0213] The embodiments described herein may take the form of a series of aperture arrays or electron-optical elements arranged in an array along a beam or multi-beam path. Such electron-optical elements may be electrostatic. In one embodiment, all electron-optical elements, e.g., from the beam-limiting aperture array to the last electron-optical element in a sub-beam path before the sample, may be electrostatic and / or in the form of aperture arrays or plate arrays. In some configurations, one or more of the electron-optical elements are fabricated as microelectromechanical systems (MEMS) (i.e., using MEMS fabrication techniques). For example, aperture arrays, plate electrodes of an objective lens array, one or more features of a detector array, a scan deflector array, and a collimator element array may be formed using MEMS fabrication techniques.

[0204]

[0214] References to upper and lower, top and bottom, and upward and downward should be understood to refer to directions parallel to the (typically, but not always, perpendicular) upstream and downstream beam directions of the electron beam or multi-beam impinging on the sample 208. References to upstream and downstream beams are therefore intended to refer to directions relative to the beam path, independent of any prevailing gravitational field. These references are intended to correspond to the general direction from the electron beam source to the sample. However, these references to the beam path may correspond to a reference relative to the electronic optical axis of the device 41. In the case of a multi-device 41, the direction of the beam path of at least one subdevice 42 (reference subdevice) may correspond to the electronic optical axis of the same subdevice 41. Other subdevices of the multi-device 41 may be calibrated relative to the reference subdevice. The electronic optical axis may correspond to a geometric axis of the reference subdevice, which in one embodiment is a geometric axis of the multi-device.

[0205]

[0215] An evaluation system according to one embodiment of the present disclosure may be a tool that performs a qualitative evaluation (e.g., pass / fail) of a sample, a tool that performs a quantitative measurement (e.g., feature size) of a sample, or a tool that generates an image of a map of a sample. Examples of evaluation systems are inspection tools (e.g., to identify defects), review tools (e.g., to classify defects), and metrology tools, or tools that can perform any combination of evaluation functions associated with an inspection tool, review tool, or metrology tool (e.g., metrology inspection tool). The electron-optical device 41 may be a component of a charged particle evaluation system 40, such as an inspection tool or metrology inspection tool, or part of an electron beam lithography tool. Any reference to a tool herein is intended to encompass a device, apparatus, or system, and a tool may include various components, for example, for data processing elements, which may or may not be collocated and may even be located in separate rooms.

[0206]

[0216] The terms "sub-beam" and "beamlet" are used interchangeably herein and should be understood to encompass any radiation obtained from a parent radiation beam by separating or splitting the parent radiation beam. The term "beam" may be used synonymously with "sub-beam" and "beamlet". The term "manipulator" is used to encompass any element that affects the path of a sub-beam or beamlet, such as a lens or deflector.

[0207]

[0217] While the invention has been described in connection with various embodiments, other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0208]

[0218] The above description is intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications can be made as described without departing from the scope of the claims set out below.

Claims

1. 1. A charged particle device for projecting multiple beams of charged particles towards a sample, comprising: a plurality of sources configured to emit respective source beams of charged particles along respective paths of a beam grid toward the sample, the beam grid including a plurality of charged particle beams; one or more elements defining an array of apertures each including a plurality of beam regions assigned to an individual source beam, the one or more elements being configured to operate on the charged particle beam within the beam grid of the individual source beams; each element is separated from an adjacent element by a spacer; A charged particle device, wherein the spacer has at least one aperture positioned to correspond to the positions of at least two beam regions.

2. The device of claim 1 , wherein the one or more elements are configured to be positioned such that the array of apertures is disposed along the path of the beam grid.

3. 3. The device of claim 1, wherein each beam region corresponds to an individual beam grid of one of the individual source beams.

4. the elements are electrodes of a lens array; Preferably, the electrode is an electrode plate, 4. A device according to any one of claims 1 to 3, wherein the lens array preferably comprises the adjacent elements and the spacers.

5. The device of any one of claims 1 to 4, wherein the spacer includes outer supports disposed between adjacent elements for supporting the adjacent elements.

6. the outer support defines the at least one aperture; Preferably, the aperture is positioned to correspond to the positions of the plurality of beam regions; 6. The device of claim 5, wherein the outer support is preferably positioned to surround the plurality of beam regions.

7. the plurality of beam regions are preferably arranged in a patterned two-dimensional array; the two-dimensional array preferably includes at least two parallel rows of beam areas; A device according to any one of claims 1 to 6, wherein each row comprises at least two beam regions.

8. the plurality of beam regions includes at least one ring of beam regions arranged in a two-dimensional ring about a central location at a midpoint of the plurality of beam regions; 8. The device of claim 7, wherein the at least one ring of beam regions preferably includes up to four rings of beam regions.

9. the two-dimensional array preferably includes beam regions arranged around an intermediate region at a central position of the plurality of beam regions; Preferably, the two-dimensional array is annular, such as an annular portion of a beam area; 8. The device of claim 7, wherein the annular portion preferably forms at least one ring.

10. the at least one ring of beam regions includes an inner ring of beam regions disposed adjacent the central location; 10. A device according to claim 8 or 9, wherein the inner ring of beam regions preferably comprises up to six beam regions.

11. the at least one ring of beam regions includes an outer ring of beam regions; an outer ring of the beam region surrounding an inner ring of the beam region; Preferably, an outer ring of the beam region is positioned concentrically around an inner ring of the beam region; 11. The device of claim 10, wherein the outer ring of beam regions preferably includes up to 20 beam regions.

12. the spacer including intermediate supports disposed between the adjacent elements for supporting the adjacent elements; the intermediate support is positioned equidistant between two adjacent beam regions, e.g., between two or more beam regions; Preferably, the location of the intermediate support corresponds to the intermediate region; Preferably, the intermediate support surrounds one or more of the beam regions and is positioned around the intermediate region, for example; For example, the spacer may have a plurality of apertures defined therein; A device according to any preceding claim, wherein the intermediate support is capable of defining one or more of the apertures therethrough.

13. the spacer including an inner support disposed between the adjacent elements for supporting the adjacent elements; the periphery of the inner support is surrounded by three or more of the beam regions; A device according to any one of claims 1 to 12, wherein the inner support is preferably positioned at a central location at the midpoint of the plurality of beam regions.

14. the one or more lens arrays include one or more condenser lens arrays; and / or 14. A device according to any one of claims 4 to 13, wherein the one or more lens arrays comprise one or more objective lens arrays configured to operate on the plurality of beams of the beam grid.

15. the one or more lens arrays include a greater number of condenser lens arrays than objective lens arrays; 15. The device of claim 14, wherein the aperture array of the condenser lens array preferably includes a more discontinuous pattern than the objective lens array.

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