Electrooptical device

Abstract

A charged particle optical apparatus for projecting a plurality of charged particle beams along respective beam paths towards a sample location, the charged particle optical apparatus comprising: a charged particle optical assembly configured to manipulate the charged particle beams, the charged particle optical assembly comprising a first charged particle optical element configured to manipulate the charged particle beams; the first charged particle optical element includes a plate having one or more apertures surrounding a beam path of the charged particle beam; and an electrical connector configured to electrically connect the plate of the first charged particle optical element to a power source, where the electrical connector: includes a shield configured to define a field-free region substantially free of an electric field; the first charged particle optical element is electrically connected to the substrate and configured to be electrically connectable via a flexible coupler configured to electrically connect the plate of the first charged particle optical element to a power source, the flexible coupler being located within the field-free region.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to EP application 22178490.3, filed on June 10, 2022, and incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments provided herein generally relate to a charged particle optical device, a charged particle optical component, a charged particle optical apparatus, a method for providing an electrical connection, and a method of disconnecting a charged particle optical component from a charged particle optical device. Background Art

[0004] When manufacturing semiconductor integrated circuit (IC) chips, during the manufacturing process, unexpected pattern defects may occur on the substrate (e.g., wafer) or mask, thereby reducing the yield. Defects may occur due to, for example, optical effects and accidental particles or other processing steps (such as etching, deposition or chemical mechanical polishing). Therefore, monitoring the degree of unexpected pattern defects is an important process in IC chip manufacturing. More generally, the inspection and / or measurement of the surface of a substrate or other object / material is an important process during and / or after its manufacture.

[0005] Pattern inspection tools with charged particle beams have been used to inspect objects, such as detecting pattern defects. These tools typically use electron microscopy techniques, such as scanning electron microscopes (SEMs). In an SEM, a primary electron beam of relatively high energy electrons is targeted at a final deceleration step so as to land on a target with a relatively low landing energy. The electron beam is focused onto the target as a probe spot. The interaction between the material structure at the probe spot and the landing electrons from the electron beam causes electrons to be emitted from the surface, such as secondary electrons, backscattered electrons, or Auger electrons. The generated secondary electrons can be emitted from the material structure of the target.

[0006] By scanning a primary electron beam as a detection spot on the target surface, secondary electrons can be emitted on the target surface. By collecting these emitted secondary electrons from the target surface, the pattern inspection tool can obtain an image-like signal representing the characteristics of the material structure of the target surface. In this inspection, the collected secondary electrons are detected by a detector within the tool. The detector generates a signal in response to an incidental particle. When an area of ​​the sample is inspected, the signal includes data that is processed to generate an inspection image corresponding to the inspected area of ​​the sample. The image may include pixels. Each pixel may correspond to a portion of the inspected area. Typically, an electron beam inspection tool has a single beam and may be referred to as a single beam SEM. Attempts to introduce multi-electron beam inspection in a tool (or 'multi-beam tool') may be referred to as a multi-beam SEM (MBSEM).

[0007] Another application of an electron optical device (or device or array) is photolithography. A beam of charged particles reacts with a layer of resist on the surface of a substrate. By controlling the position on the resist layer towards which the beam of charged particles is directed, a desired pattern can be created in the resist.

[0008] Electron-optical devices may be apparatus for generating, irradiating, projecting and / or detecting one or more charged particle beams. The paths of charged particle beams are controlled by electromagnetic fields (i.e., electrostatic and magnetic fields). Stray electromagnetic fields may cause the beams to be steered undesirably.

[0009] In some electro-optical devices, an electrostatic field is typically generated between two electrodes. A high voltage needs to be applied to the electrodes. High voltage cables are rigid, and forces applied to such high voltage cables connected to such electrodes may undesirably affect the position and / or performance, such as the formation (as well as deformation) of the electrode to which the cable is connected, or even the electrodes in the electrode stack to which the cable is connected. Summary of the invention

[0010] The present invention provides a suitable architecture to achieve the desired high voltage connection while reducing the risk of the connection undesirably affecting the location and / or formation of the connection electrode. According to a first aspect of the present invention, there is provided a charged particle optical device for projecting multiple charged particle beams toward a sample position along corresponding beam paths, the charged particle optical device comprising: a charged particle optical component configured to manipulate the charged particle beam, the charged particle optical component comprising a first charged particle optical element, the first charged particle optical element comprising a plate having one or more apertures surrounding the beam path of the charged particle beam; and an electrical connector configured to electrically connect the plate of the charged particle optical element to a power source, wherein the electrical connector: comprises a shield configured to define a field-free region substantially free of an electric field; and is configured to be electrically connected via a flexible coupler, the flexible coupler being configured to electrically connect the plate of the charged particle optical element to a power source, the flexible coupler being located within the field-free region. The field-free region is field-free relative to the flexible coupler.

[0011] According to a second aspect of the invention, there is provided a charged particle optical component for manipulating one or more charged particle beams in a charged particle device along a beam path toward a sample position, the charged particle optical component comprising: a charged particle optical element comprising a plate having one or more apertures surrounding the beam path of the one or more charged particle beams and configured to manipulate the one or more charged particle beams; and at least one isolator adjacent to the plate around the beam path and configured to mechanically support the plate and electrically isolate the plate; and an electrical connector configured to electrically connect the plate to a power source, wherein the electrical connector comprises a plate protrusion extending radially outward of an outer periphery of the isolator or one of the isolators relative to the beam path, the protrusion being configured to be connectable to the power source via a flexible coupler in a field-free region substantially free of an electric field. The field-free region is field-free relative to the flexible coupler.

[0012] According to a third aspect of the invention, a charged particle optical component is provided, which is configured to guide multiple charged particle beams in a beam grid toward a sample, and the component includes a charged particle optical component, which includes: a planar charged particle optical element, which is configured to operate at a high voltage on the charged particle beam of the beam grid, and the element includes multiple apertures for different beam paths of the beam grid; and an isolation spacer, which is configured to: support and electrically isolate the charged particle optical element and be positioned away from the beam path; and an electrical conductor, which is structurally connected to a connection surface of the component and electrically connected to the charged particle element, wherein a groove is defined in the electrical conductor and is configured to provide a field-free volume for inserting an electrical coupler to electrically connect the charged particle optical element to the electrical conductor via the electrical coupler.

[0013] According to a fourth aspect of the present invention, a method for providing an electrical connection is provided, the method comprising: providing a charged particle optical device, the charged particle optical device being configured to project a plurality of charged particle beams along corresponding beam paths toward a sample position, the charged particle optical device comprising a charged particle optical component configured to manipulate the charged particle beam, the charged particle optical component comprising a charged particle optical element comprising a plate having one or more apertures surrounding the beam path of the charged particle beam; and providing an electrical connector, the electrical connector being configured to electrically connect the plate to a power source, wherein the electrical connector: comprises a shielding member configured to define a field-free region having substantially no electric field; and is configured to be electrically connectable to a flexible coupler, the flexible coupler being configured to electrically connect the plate to a power source, the flexible coupler being located within the field-free region.

[0014] According to a fourth aspect of the present invention, a method for disconnecting a charged particle optical component from a charged particle optical device is provided, the charged particle optical device being configured to project multiple charged particle beams along corresponding beam paths toward a sample position, the charged particle optical device comprising a charged particle optical component configured to manipulate the charged particle beams, the charged particle optical component comprising a charged particle optical element comprising a plate having one or more apertures surrounding the beam path of the charged particle beam, the plate being electrically connected to a power supply via a flexible coupler located in a field-free region defined by a shield, the method comprising: electrically disconnecting the plate from a power supply by disconnecting the flexible coupler from one of the power supply and the charged particle optical component, wherein the flexible coupler remains connected to the other of the charged particle optical component and the power supply.

[0015] Advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which certain embodiments of the invention are set forth by way of illustration and example. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other aspects of the present disclosure will become more apparent through the description of exemplary embodiments with reference to the attached drawings.

[0017] Figure 1 is a schematic diagram illustrating an exemplary electron beam inspection apparatus.

[0018] Figure 2 It is illustrated as Figure 1 A schematic diagram of an exemplary multi-beam electron optical device of a portion of an exemplary electron beam inspection apparatus.

[0019] Figure 3 is a schematic diagram of an exemplary electro-optical device including a Figure 1 A collimator element array and a scanning deflector array of a portion of an exemplary electron beam inspection apparatus.

[0020] Figure 4 Yes Figure 3 Schematic diagram of an exemplary electron-optical device array of electron-optical devices.

[0021] Figure 5 It is illustrated as Figure 1 A schematic diagram of an alternative exemplary electron optical device of a portion of an exemplary electron beam inspection apparatus.

[0022] Figure 6 As Figure 3 , Figure 4 and Figure 5 Schematic diagram of an exemplary electron-optical assembly of a portion of an electron-optical device.

[0023] Figure 7is a schematic diagram of an electrical connector for an exemplary electronic optical assembly.

[0024] Figure 8 is a schematic diagram of an electrical connector for an exemplary electronic optical assembly.

[0025] Fig. 9 is a plan view of an electrical connector of an exemplary electronic optical assembly.

[0026] Fig.10 yes Figure 8 A cross-sectional view of the electrical connector shown.

[0027] Fig.11 is a schematic diagram of an electrical connector for an exemplary electronic optical assembly.

[0028] Fig.12 is a schematic diagram of an electrical connector for an exemplary electronic optical assembly.

[0029] Fig.13 is a schematic diagram of an electrical connector for an exemplary electronic optical assembly.

[0030] Fig.14 is a schematic diagram of an electrical connector for an exemplary electronic optical assembly.

[0031] Fig.15 Yes Fig.14 Different views of an electrical connector of an electrical connector are shown.

[0032] Fig.16 is a schematic diagram of the connection between a shield and a flexible coupling of an electrical connector.

[0033] Fig.17 is a schematic diagram of the connection between a shield and a flexible coupling of an electrical connector.

[0034] Fig.18 is a schematic diagram of the connection between a shield and a flexible coupling of an electrical connector.

[0035] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the present invention. Instead, they are merely examples of devices and methods consistent with various aspects of the present invention as recited in the appended claims. DETAILED DESCRIPTION

[0036] By significantly increasing the packing density of circuit components such as transistors, capacitors, diodes, etc. on IC chips, a reduction in the physical size of the device and an increase in the computing power of electronic devices can be achieved. This is achieved by increasing the resolution, which enables the manufacture of smaller structures. Semiconductor IC manufacturing is a complex and time-consuming process with hundreds of individual steps. Errors in any step of the process of manufacturing IC chips are likely to have an adverse effect on the operation of the final product. Just one defect can cause device failure. It is expected to increase the overall yield of the process. For example, in order to obtain a 75% yield of a 50-step process (where one step can indicate the number of layers formed on the wafer), the yield of each individual step must be greater than 99.4%. If the yield of the individual step is 95%, the overall process yield will be as low as 7% to 8%.

[0037] Maintaining high substrate (i.e., wafer) throughput (defined as the number of substrates processed per hour) is also desirable. The presence of defects may affect high process yield and high substrate throughput. This is especially true if reviewing the defect requires operator intervention. Detecting and identifying micron and nanometer-scale defects with high throughput by inspection tools such as scanning electron microscopes ('SEM') is desirable to maintain high yield and low cost of IC chips.

[0038] The scanning electron microscope comprises a scanning device and a detector device. The scanning device comprises an irradiation device, which comprises an electron source for generating primary electrons and a projection device for scanning a target such as a substrate with one or more focused primary electron beams. The primary electrons interact with the target and generate interaction products, such as secondary electrons and / or backscattered electrons. When scanning the target, the detection device captures secondary electrons and / or backscattered electrons from the target so that the scanning electron microscope can create an image of the scanned area of ​​the target. The design of the electron optical tool implementing these scanning electron microscope features can have a single beam. For higher throughput such as for inspection, some designs of the device use multiple focused primary electron beams, i.e., multiple beams. The component beams in the multiple beams can be referred to as sub-beams or beam waves. Multiple beams can scan different parts of the target simultaneously. Therefore, a multi-beam inspection device can inspect the target faster than a single-beam inspection device, for example by moving the target at a higher speed.

[0039] In a multi-beam inspection apparatus, the paths of some primary electron beams are displaced away from the central axis of the scanning device, i.e., the midpoint of the primary electron optical axis (also referred to herein as the charged particle axis). In order to ensure that all electron beams arrive at the sample surface at substantially the same angle of incidence, it is necessary to manipulate the beamlet paths with a larger radial distance from the central axis to move through a larger angle than the beamlet paths with paths closer to the central axis. This stronger manipulation may cause aberrations, making the resulting image blurred and out of focus. An example is spherical aberration, which brings the focus of each beamlet path into a different focal plane. In particular, for beamlet paths that are not on the central axis, the change in the focal plane in the beamlet is greater with radial displacement from the central axis. When secondary electrons from the target are detected, such aberrations and defocus effects may still be associated with them, for example, the shape and size of the spot formed by the beamlet on the target will be affected. Therefore, such aberrations reduce the quality of the resulting image created during the inspection.

[0040] The following describes a known implementation of a multi-beam inspection device.

[0041] The drawings are schematic. Therefore, for the sake of clarity, the relative sizes of the components in the drawings are exaggerated. In the following description of the drawings, the same or similar reference numerals refer to the same or similar components or entities, and only the differences with respect to the various embodiments are described. Although the description and drawings refer to electron-optical devices, it is to be understood that the embodiments are not used to limit the present disclosure to specific charged particles. Therefore, throughout this document, references to electrons and items referenced to electrons may be more generally considered to be references to and items referenced to charged particles, which are not necessarily electrons.

[0042] Now refer to Figure 1 , Figure 1 is a schematic diagram illustrating an exemplary electron beam evaluation apparatus or inspection apparatus 100 . Figure 1 The inspection apparatus 100 includes a vacuum chamber 10, a load lock chamber 20, an electron optical device, an equipment front end module (EFEM) 30, and a controller 50. The electron optical device 40 may be within the vacuum chamber 10. The electron optical device may include the electron optical device 40 (also referred to as an electron optical device, an electron beam device, or an electron beam device) and a motorized or actuated stage.

[0043] The EFEM 30 includes a first loading port 30a and a second loading port 30b. The EFEM 30 may include additional loading ports (multiple). The first loading port 30a and the second loading port 30b may, for example, accommodate a substrate front opening pod (FOUP) containing a substrate to be inspected (e.g., a semiconductor substrate or a substrate made of (multiple) other materials) or a target (substrate, wafer, and sample are collectively referred to as "target" hereinafter). One or more robotic arms (not shown) in the EFEM 30 transport the target to the load lock chamber 20.

[0044] The load lock chamber 20 is used to remove gas around the target. The load lock chamber 20 can be connected to a load lock vacuum pump system (not shown), which removes gas particles in the load lock chamber 20. The operation of the load lock vacuum pump system enables the load lock chamber to reach a first pressure lower than atmospheric pressure. The main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas molecules in the main chamber 10 so that the pressure around the target reaches a second pressure lower than the first pressure. After reaching the second pressure, the target is transported to the electron optical device 40, and the target can be inspected by the electron optical device 40. The electron optical device 40 may include a single beam or multi-beam electron optical device.

[0045] The controller 50 is electronically connected to the electron optical device 40. The controller 50 may be a processor (such as a computer) configured to control the charged particle beam inspection apparatus 100. The controller 50 may also include processing circuitry configured to perform various signal and image processing functions. Figure 1 Controller 50 is shown as being outside of a structure including main chamber 10, load lock chamber 20, and EFEM 30, but it is to be understood that controller 50 may be part of the structure. Controller 50 may be located in one of the components of the charged particle beam inspection device, or it may be distributed over at least two components. Although the present disclosure provides an example of a main chamber 10 for housing an electron beam inspection tool, it should be noted that the broadest aspects of the present disclosure are not limited to chambers for housing electron optical equipment. On the contrary, it is to be understood that the aforementioned principles may also be applied to other arrangements of other tools and devices operating at a second pressure.

[0046] Now refer to Figure 2 , Figure 2 yes Figure 1Schematic diagram of an exemplary multi-beam electron optical device 40 of the inspection device 100. In an alternative embodiment, the inspection device 100 is a single beam inspection device. The electron optical device 40 may include an electron source 201, a beam former array 372 (also known as a gun hole plate, a Coulomb aperture array, or a pre-beamlet forming aperture array), a converging lens 310, a source converter (or micro-optical array) 320, an objective lens 331, and a target 308. In an embodiment, the converging lens 310 is magnetic. The target 308 may be supported by a support on a platform. The platform may be motorized. The platform moves so that the target 308 is scanned electronically by chance. The electron source 201, the beam former array 372, the converging lens 310 may be components of an irradiation device included in the electron optical device 40. The source converter 320 (also known as a source conversion unit) and the objective lens 331 described in more detail below may be components of a projection device included in the electron optical device 40.

[0047] The electron source 201, the beam former array 372, the converging lens 310, the source converter 320 and the objective lens 331 are aligned with the primary electron optical axis 304 of the electron optical device 40. The electron source 201 can generate a primary beam 302 that is generally along the electron optical axis 304 and has a source intersection point (virtual or real) 301S. During operation, the electron source 201 is configured to emit electrons. The electrons are extracted or accelerated by the extractor and / or the anode to form the primary beam 302.

[0048] The beam former array 372 cuts the peripheral electrons of the primary electron beam 302 to reduce the Coulomb effect caused thereby. The primary electron beam 302 can be trimmed into a specified number of sub-beams, such as three sub-beams 311, 312 and 313 by the beam former array 372. It should be understood that the description is intended to be applied to an electron optical device 40 having any number of sub-beams (such as one, two or more than three). In operation, the beam former array 372 is configured to block peripheral electrons to reduce the Coulomb effect. The Coulomb effect may enlarge the size of each of the detection spots 391, 392, and 393, thereby reducing the inspection resolution. The beam former array 372 reduces the aberrations caused by the Coulomb interaction between the electrons projected in the beam. The beam former array 372 may include a plurality of openings for generating primary sub-beams even before the source converter 320.

[0049] Source converter 320 is configured to convert the beam (including beamlets, if any) transmitted by beamformer array 372 into beamlets that are projected toward target 308. In an embodiment, source converter is a unit. Alternatively, the term source converter may be simply used as a collective name for a group of components that form a beam from beamlets.

[0050] like Figure 2As shown, in an embodiment, the electron optical device 40 includes a beam limiting aperture array 321 having an aperture pattern (i.e., apertures arranged in formation) configured to limit the outer dimensions of the beam (or beamlets) projected toward the target 308. In an embodiment, the beam limiting aperture array 321 is part of the source converter 320. In an alternative embodiment, the beam limiting aperture array 321 is part of the system in the upstream direction of the main device. In an embodiment, the beam limiting aperture array 321 divides one or more beamlets 311, 312, 313 into beams, so that the number of beams projected toward the target 308 is greater than the number of beamlets transmitted through the beam former array 372. In an alternative embodiment, the beam limiting aperture array 321 maintains the number of beamlets incident on the beam limiting aperture array 321, in which case the number of beamlets may be equal to the number of beams projected toward the target 308.

[0051] like Figure 2 As shown, in an embodiment, the electron optical device 40 includes a pre-bend deflector array 323 having pre-bend deflectors 323_1, 323_2 and 323_3 to respectively bend the beamlets 311, 312 and 313. The pre-bend deflectors 323_1, 323_2 and 323_3 can bend the paths of the beamlets 311, 312 and 313 onto the beam-limiting aperture array 321.

[0052] The electron optical device 40 may also include an image forming element array 322 having image forming deflectors 322_1, 322_2 and 322_3. There are corresponding deflectors 322_1, 322_2 and 322_3 associated with the path of each beam wave. The deflectors 322_1, 322_2 and 322_3 are configured to deflect the path of the beam wave toward the electron optical axis 304. The deflected beam wave forms a virtual image (not shown) of the source intersection 301S. In the current embodiment, these virtual images are projected onto the target 308 through the objective lens 331, and detection spots 391, 392, 393 are formed thereon. The electron optical device 40 may also include an aberration compensator array 324, which is configured to compensate for the aberrations that may exist in each sub-beam in the sub-beam. In an embodiment, the aberration compensator array 324 includes a lens configured to operate on the corresponding beam wave. The lens may take the form of a lens array. The lenses in the array can operate at different beams of the multiple beams. The aberration compensator array 324 may include, for example, a field curvature compensator array (not shown) having microlenses. For example, the field curvature compensator and the microlenses may be configured to compensate each sub-beam for a field curvature aberration that is apparent in the detection spots 391, 392, and 393. The aberration compensator array 324 may include an astigmatism compensator array (not shown) having a micro-stigmatizer. For example, the micro-stigmatizer may be controlled to operate the sub-beams to compensate for the astigmatism aberration present in the detection spots 391, 392, and 393.

[0053] The source converter 320 may further include a pre-bend deflector array 323 having pre-bend deflectors 323_1, 323_2, and 323_3 to bend the beamlets 311, 312, and 313, respectively. The pre-bend deflectors 323_1, 323_2, and 323_3 may bend the paths of the beamlets onto the beam-limiting aperture array 321. In an embodiment, the pre-bend micro-deflector array 323 may be configured to bend the beamlet paths of the beamlets toward an orthogonal straight line of the plane of the beam-limiting aperture array 321. In an alternative embodiment, the converging lens 310 may adjust the path directions of the beamlets onto the beam-limiting aperture array 321. The converging lens 310 may, for example, focus (collimate) the three sub-beams 311, 312, and 313 to become substantially parallel beams along the primary electron optical axis 304, so that the three sub-beams 311, 312, and 313 are substantially perpendicularly incident on the source converter 320, which may correspond to the beam-limiting aperture array 321. In such an alternative embodiment, the pre-bend deflector array 323 may not be necessary.

[0054] The image forming element array 322, the aberration compensator array 324 and the pre-bent deflector array 323 may include multiple layers of beamlet steering devices, some of which may be in array form, such as: micro-deflectors, micro-lenses or micro-stigmators. The beam path may be rotationally steered. Rotational correction may be applied by magnetic lenses. Rotational correction may be additionally or alternatively achieved by existing magnetic lenses, such as a converging lens arrangement.

[0055] In the present example of the electron optical device 40, the beams are deflected towards the electron optical axis 304 by deflectors 322_1, 322_2 and 322_3 of the image forming element array 322, respectively. It should be understood that the beam paths may have corresponded to the electron optical axis 304 before reaching the deflectors 322_1, 322_2 and 322_3.

[0056] The objective lens 331 focuses the beam onto the surface of the target 308, i.e., it projects three virtual images onto the target surface. The three images formed on the target surface by the three sub-beams 311 to 313 form three detection spots 391, 392 and 393 thereon. In an embodiment, the deflection angles of the sub-beams 311 to 313 are adjusted so that they pass through or approach the front focus of the objective lens 331 to reduce or limit the off-axis aberrations of the three detection spots 391 to 393. In the arrangement, the objective lens 331 is magnetic. Although three beams are mentioned, this is only by way of example. There may be any number of beams.

[0057] The manipulator is configured to manipulate one or more charged particle beams. The term manipulator encompasses deflectors, lenses, and apertures. The pre-bent deflector array 323, the aberration compensator array 324, and the image forming element array 322 may be referred to as a manipulator array individually or in combination with one another because they manipulate one or more sub-beams or beam waves of charged particles. The lenses and deflectors 322_1, 322_2, and 322_3 may be referred to as manipulators because they manipulate one or more sub-beams or beam waves of charged particles.

[0058] In an embodiment, a beam splitter (not shown) is provided. The beam splitter may be in the downstream direction of the source converter 320. The beam splitter may be, for example, a Wien filter including an electrostatic dipole field and a magnetic dipole field. The beam splitter may be positioned between adjacent shield sections along the direction of the beam path (described in more detail below). The inner surface of the shield may be located radially inward of the beam splitter. Alternatively, the beam splitter may be within the shield. In operation, the beam splitter may be configured to apply an electrostatic force to each electron of a beamlet through an electrostatic dipole field. In an embodiment, the magnitude of the electrostatic force is equal to the magnetic force applied by the magnetic dipole field of the beam splitter on each primary electron of the beamlet, but in opposite directions. Thus, the beamlet may pass through the beam splitter at least substantially straight with a deflection angle of at least substantially zero. The direction of the magnetic force depends on the direction of motion of the electrons, while the direction of the electrostatic force does not depend on the direction of motion of the electrons. Therefore, since secondary electrons and backscattered electrons generally move in the opposite direction compared to primary electrons, the magnetic forces exerted on the secondary electrons and backscattered electrons will no longer counteract the electrostatic forces, and thus the secondary electrons and backscattered electrons moving through the beam splitter will be deflected away from the electron optical axis 304.

[0059] In an embodiment, a secondary device (not shown) is provided, which includes detection elements for detecting a corresponding secondary charged particle beam. When the secondary beam is incident with the detection elements, these elements can generate a corresponding intensity signal output. The output can be directed to an image processing system (e.g., controller 50). Each detection element can include an array, which can be in the form of a grid. The array can have one or more pixels; each pixel can correspond to an element of the array. The intensity signal output of the detection element can be the sum of the signals generated by all pixels in the detection element.

[0060] In an embodiment, a secondary projection device and its associated electronic detection equipment (not shown) are provided. The secondary projection device and its associated electronic detection equipment can be aligned with the secondary electron optical axis of the secondary device. In an embodiment, the beam splitter is arranged to deflect the path of the secondary electron beam toward the secondary projection device. The secondary projection device then focuses the path of the secondary electron beam onto multiple detection areas of the electronic detection equipment. The secondary projection device and its associated electronic detection equipment can use secondary electrons or backscattered electrons to register and generate an image of the target 308.

[0061] In an embodiment, the inspection device 100 includes a single source.

[0062] Any element or collection of elements can be replaced within the electron-optical device or replaced in the field. One or more electron-optical components in the electron-optical device (particularly those electron-optical components that operate on or generate beamlets, such as aperture arrays and manipulator arrays) may include one or more micro-electromechanical systems (MEMS). The pre-bent deflector array 323 may be a MEMS. MEMS are miniaturized mechanical and electromechanical components manufactured using micromachining techniques. In an embodiment, the electron-optical device 40 includes an aperture, a lens, and a deflector formed as a MEMS. In an embodiment, manipulators such as lenses and deflectors 322_1, 322_2, and 322_3 as a whole array can be passively or actively controlled individually or in groups within the array to control the beam wave of charged particles projected toward the target 308.

[0063] In embodiments, the electron-optical device 40 may include alternative and / or additional components on the charged particle path, such as lenses and other components, some of which have been described earlier with reference to Figure 1 and Figure 2 An example of such an arrangement is Figure 3 and Figure 4 As shown, it will be described in further detail later. In particular, an embodiment includes an electron optical device 40, which divides the charged particle beam from the source into a plurality of sub-beams. A plurality of corresponding objective lenses can project the sub-beams onto the sample. In some embodiments, a plurality of converging lenses are provided in the upstream direction from the objective lens. The converging lens focuses each sub-beam in the sub-beam to the intermediate focus in the upstream direction of the objective lens. In some embodiments, a collimator is provided in the upstream direction from the objective lens. A corrector can be provided to reduce focusing errors and / or aberrations. In some embodiments, such a corrector is integrated into the objective lens or positioned directly adjacent to the objective lens. In the case of providing a converging lens, such a corrector can be additionally or alternatively integrated into the converging lens or positioned directly adjacent to it, and / or positioned in the intermediate focus or positioned directly adjacent to it. A detector is provided to detect the charged particles emitted by the sample. The detector can be integrated into the objective lens. The detector can be located on the bottom surface of the objective lens so as to face the sample in use. The detector can include an array, which can correspond to a beam wave array arranged in multiple beams. The detector in the detector array can generate a detection signal that can be associated with a pixel of the generated image. The converging lens, the objective lens and / or the detector may be formed as MEMS or CMOS devices.

[0064] Figure 3is a schematic diagram of another design of an exemplary electron-optical device 40. The electron-optical device 40 may include a source 201 and one or more electron-optical components. Alternatively, an electron-optical device including the electron-optical device 40 may include the source 201. The electron-optical device 40 may include an upper beam limiter 252, a collimator element array 271, a control lens array 250, a scanning deflector array 260, an objective lens array 241, a beam shaping limiter 242, and a detector array. The source 201 provides a beam of charged particles (e.g., electrons). The multiple beams focused on the sample 208 are derived from the beam provided by the source 201. For example, a beam limiter that defines an array of beam-limiting apertures can be used to derive sub-beams from the beam. The source 201 is desirably a high-brightness thermal field emitter with a good compromise between brightness and total emission current.

[0065] The upper beam limiter 252 defines a beam limiting aperture array. The upper beam limiter 252 may be referred to as an upper beam limiting aperture array or an upstream beam limiting aperture array. The upper beam limiter 252 may include a plate (which may be a plate-like body) having a plurality of apertures. The upper beam limiter 252 forms a beamlet from the charged particle beam emitted from the source 201. Portions of the beam other than those portions that contribute to the formation of the beamlet may be blocked (e.g., absorbed) by the upper beam limiter 252 so as not to interfere with the beamlets in the downstream direction. The upper beam limiter 252 may be referred to as a beamlet limiting aperture array.

[0066] The collimator element array 271 is provided in the downstream direction of the upper beam limiter. Each collimator element collimates the corresponding sub-beam. The collimator element array 271 can be formed using MEMS manufacturing technology so as to be compact in space. Figure 3 In some of the illustrated embodiments, the collimator element array 271 is the first deflection or focusing electron optical array element in the beam path in the downstream direction of the source 201. In another arrangement, the collimator can take the form of a macro collimator in whole or in part. Such a macro collimator can be in the upstream direction of the upper beam limiter 252, so that it operates on the beam from the source before generating multiple beams. A magnetic lens can be used as a macro collimator.

[0067] There is a control lens array 250 in the downstream direction of the collimator element array. 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 corresponding potential source. The control lens array 250 may include two or more (e.g., three) plate electrode arrays connected to a corresponding potential source. The control lens array 250 is associated with the objective lens array 241 (e.g., the two arrays are positioned close to each other and / or mechanically connected to each other and / or controlled together as a unit). The control lens array 250 is positioned in the upstream direction of the objective lens array 241. The control lens pre-focuses the beamlets (e.g., applies a focusing effect to the beamlets before the beamlets reach the objective lens array 241). Pre-focusing can reduce the divergence of the beamlets or increase the convergence rate of the beamlets.

[0068] As mentioned, the control lens array 250 is associated with the objective lens array 241. As mentioned above, the control lens array 250 can be regarded as providing electrodes in addition to the electrodes 242, 243 of the objective lens array 241, for example as part of the objective lens array assembly. The additional electrodes of the control lens array 250 allow further degrees of freedom for controlling the electron optical parameters of the sub-beams. In an embodiment, the control lens array 250 can be regarded as an additional electrode of the objective lens array 241, thereby enabling additional functionality of the corresponding objective lenses in the objective lens array 241. In an arrangement, such electrodes can be regarded as part of the objective lens array, providing additional functionality for the objective lenses of the objective lens array 241. In such an arrangement, even if the control lens is only referred to as part of the objective lens, for example in terms of providing one or more additional degrees of freedom for the objective lens, the control lens is also regarded as part of the corresponding objective lens.

[0069] For ease of illustration, lens arrays are schematically depicted herein by an array of ellipses. Each ellipse represents one of the lenses in the lens array. By convention, ellipses are used to represent lenses, similar to the biconvex form often used in optical lenses. However, in the context of charged particle arrangements such as those discussed herein, it is understood that the lens array will generally operate electrostatically and therefore any physical elements that take the shape of biconvex may not be required. As described above, the lens array may instead include multiple plates having apertures.

[0070] A scanning deflector array 260 including a plurality of scanning deflectors may be provided. The scanning deflector array 260 may be formed using MEMS manufacturing techniques. Each scanning deflector scans a corresponding beamlet on the sample 208. Therefore, the scanning deflector array 260 may include a scanning deflector for each beamlet. Each scanning deflector may deflect the beamlet in one direction (e.g. parallel to a single axis, such as the X axis) or in two directions (e.g. relative to two non-parallel axes, such as the X and Y axes). Deflection such as scanning the beamlet across the sample 208 along one or two directions (i.e., one-dimensionally or two-dimensionally). In an embodiment, the scanning deflector described in EP2425444 may be used to implement the scanning deflector array 260, which document is incorporated herein by reference in its entirety specifically in relation to the scanning deflector. The scanning deflector array 260 (e.g. formed using the MEMS manufacturing techniques mentioned above) may be more compact in space than a macro scanning deflector. In another arrangement, a macro scanning deflector may be used in the upstream direction of the upper beam limiter 252. Its functionality may be similar or equivalent to that of a scanning deflector array, although it manipulates the beams from the source before generating beam waves for the multiple beams.

[0071] An objective lens array 241 including a plurality of objective lenses is provided to direct the beamlets onto the sample 208. Each objective lens includes at least two electrodes (e.g., two or three electrodes) connected to a corresponding potential source. The objective lens array 241 may include two or more (e.g., three) plate electrode arrays connected to a corresponding potential source. Each objective lens formed by the plate electrode array may be a microlens that operates on different beamlets. Each plate defines a plurality of apertures (which may also be referred to as holes). The position of each aperture in the plate corresponds to the position of a corresponding aperture (or apertures) in another plate (or plates). The corresponding apertures define the objective lens, so that each set of corresponding apertures operates on the same beamlet in multiple beams in use. Each objective lens projects a corresponding beamlet of multiple beams onto the sample 208.

[0072] Compared with an objective lens array 241 with more electrodes, an objective lens array 241 with only two electrodes can have lower aberrations. A three-electrode objective lens can have a larger potential difference between the electrodes, thus achieving a stronger lens. Additional electrodes (i.e., more than two electrodes) provide additional degrees of freedom for controlling electron trajectories, such as to focus secondary electrons as well as the incident beam. Such additional electrodes can be considered to form a control lens array 250. Compared to a single lens, the benefit of a two-electrode lens is that the energy of the incoming beam is not necessarily the same as the energy of the outgoing beam. Beneficially, the potential difference on this two-electrode lens array enables it to be used as an acceleration or deceleration lens array.

[0073] The objective lens array may form part of an objective lens array assembly together with any one or all of the scanning deflector array 260, the control lens array 250, and the collimator element array 271. The objective lens array assembly may also include a beam shaping limiter 242. The beam shaping limiter 242 defines a beam limiting aperture array. The beam shaping limiter 242 may be referred to as a lower beam limiter, a lower beam limiting aperture array, or a final beam limiting aperture array. The beam shaping limiter 242 may include a plate (which may be a plate-shaped body) having a plurality of apertures. The beam shaping limiter 242 is in a downstream direction from at least one electrode (optionally from all electrodes) of the control lens array 250. In some embodiments, the beam shaping limiter 242 is in a downstream direction from at least one electrode (optionally from all electrodes) of the objective lens array 241.

[0074] In the arrangement, the beam shaping limiter 242 is structurally integrated with the electrode 302 of the objective lens array 241. Desirably, the beam shaping limiter 242 is positioned in an area of ​​low electrostatic field strength. Each of the beam limiting apertures is aligned with a corresponding objective lens in the objective lens array 241. The alignment is such that a portion of a beamlet 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, allowing only a selected portion of the beamlets incident on the beam shaping limiter 242 to pass through the beam limiting aperture. The selected portion may be such that only a portion of the corresponding beamlet that passes through a central portion of the corresponding aperture in the objective lens array reaches the sample. The central portion may have a circular cross-section and / or be centered on the beam axis of the beamlet.

[0075] In an embodiment, the electronic optical device 40 is configured to control the objective lens array assembly (e.g., by controlling the potential applied to the 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. Therefore, the control lens array 250 and the objective lens array 241 can be positioned relatively close together, and the focusing effect 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. The control lens array and the objective lens array operate together for a combined focal length to the same surface. Combined operation without an intermediate focus can reduce the risk of aberrations. 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.

[0076] A power source may be provided to apply corresponding potentials to electrodes of the control lenses in the control lens array 250 and the objective lenses in the objective lens array 241 .

[0077] In addition to the objective lens array 241, providing a control lens array 250 provides additional degrees of freedom for controlling the characteristics of the sub-beams. Even when the control lens array 250 and the objective lens array 241 are provided relatively close together, additional degrees of freedom are provided, for example, so that no intermediate focus is 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 opening angle relative to the beam reduction rate and / or control the beam energy delivered to the objective lens array 241. The control lens may include two or three or more electrodes. If there are two electrodes, the reduction rate and the landing energy will be controlled together. If there are three or more electrodes, the reduction rate and the landing energy can be controlled independently. Therefore, the control lens can be configured to adjust the reduction rate and / or the beam opening angle and / or the landing energy of the corresponding sub-beam on the substrate (for example, using a power supply to apply appropriate corresponding potentials to the electrodes of the control lens and the objective lens). This optimization can be achieved without excessively negatively affecting the number of objective lenses and without excessively reducing the aberrations of the objective lenses (for example, without reducing the strength of the objective lenses). The use of a control lens array enables the objective lens array to operate at its optimal electric field strength. Note that it is intended that references to reduction ratio and opening angle are intended to refer to variations of the same parameter. In an ideal arrangement, the product of the range of reduction ratios and the corresponding opening angles is constant. However, the opening angle may be affected by the aperture used.

[0078] In an embodiment, the landing energy can be controlled to a desired value within a predetermined range, for example, from 1000 eV to 5000 eV. Desirably, the landing energy is changed primarily by controlling the energy of the electrons leaving the control lens. The potential difference within the objective lens is preferably kept constant during this change so that the electric field within the objective lens remains as high as possible. In addition, the potential applied to the control lens can be used to optimize the beam opening angle and the reduction ratio. The control lens can be used to change the reduction ratio in view of the change in the landing energy. Desirably, each control lens includes three electrodes to provide two independent control variables. For example, one of the electrodes can be used to control the magnification, while a different electrode can be used to independently control the landing energy. Alternatively, each control lens may have only two electrodes. When there are only two electrodes, one of the electrodes may need to control both the magnification and the landing energy.

[0079] A detector array (not shown) is provided to detect charged particles emitted from the sample 208. The detected charged particles may include any charged particles detected by a scanning electron microscope, including secondary and / or backscattered electrons emitted from the sample 208. The detector may be an array that provides an electron optical device surface facing the sample 208 (e.g., the bottom surface of the electron optical device). Alternatively, the detector array is in the upstream direction of the bottom surface, or, for example, in the upstream direction of the objective lens array or the control lens array. The elements of the detector array may correspond to beam waves of a multi-beam arrangement. The signals generated by detecting electrons by the elements of the array are sent to a processor to generate an image. The signals may correspond to pixels of an image.

[0080] In other embodiments, a macro-scanning deflector and a scanning deflector array 260 are provided. In such an arrangement, scanning of the beamlets over the sample surface can be achieved by controlling the macro-scanning deflector and the scanning deflector array 260 together, preferably synchronously.

[0081] In an embodiment, Figure 4 As illustrated, an array 500 of electron optical devices is provided. The array 500 may include a plurality of any electron optical devices described herein. Each electron optical device in the electron optical device focuses corresponding multiple beams simultaneously onto different regions of the same sample. Each electron optical device may form sub-beams from charged particle beams from different corresponding sources 201. Each corresponding source 201 may be one source among a plurality of sources 201. At least a subset of a plurality of sources 201 may be provided as a source array. The source array may include a plurality of sources 201 provided on a common substrate. Focusing a plurality of multiple beams simultaneously onto different regions of the same sample allows for simultaneous processing (e.g., evaluation) of an increased area of ​​the sample 208. The electron optical devices in the array 500 may be arranged adjacent to each other so as to project corresponding multiple beams onto adjacent regions of the sample 208.

[0082] Any number of electron-optical devices may be used in array 500. Preferably, the number of electron-optical devices ranges from two (2) (ideally nine (9)) to one hundred (100) or even two hundred (200). In embodiments, the electron-optical devices are arranged in a rectangular array or a hexagonal array. In other embodiments, the electron-optical devices are provided in an irregular array or a regular array having a geometric shape other than rectangular or hexagonal. When reference is made to a single electron-optical device, each electron-optical device in array 500 may be configured in any manner described herein, such as specifically described above with respect to reference Figure 6 The embodiments shown and described are described. Details on how the objective lenses can be combined and adapted for use in a multi-device arrangement are described in EPA 20184161.6 filed on July 6, 2020, which is incorporated herein by reference.

[0083] exist Figure 4 In the example, array 500 includes the above reference Figure 3 A plurality of electron-optical devices of the type described. Thus, each of the electron-optical devices in this example includes both a scanning deflector array 260 and a collimator element array 271. As mentioned above, the scanning deflector array 260 and the collimator element array 271 are particularly suitable for incorporation into the electron-optical device array 500 due to their spatial compactness, which helps to position the electron-optical devices close to each other. This arrangement of electron-optical devices may be advantageous over other arrangements that use magnetic lenses as collimators. For example, due to magnetic interference between columns, it may be challenging to incorporate a magnetic lens into an electron-optical device intended for a multi-device arrangement (e.g., a multi-column arrangement).

[0084] Except for the following description and Figure 5 In addition to the illustrated diagram, alternative designs of multi-beam electron optics may have Figure 3 The same features described. An alternative design of the multi-beam electron optical device may include a converging lens array 231 in the upstream direction of the objective lens array arrangement 241, as disclosed in EP application 20158804.3 filed on February 21, 2020, which is incorporated herein by reference, as long as the multi-beam device with a collimator and its components are described. This design does not require a beam shaping limiter array 242 or an upper beam limiter array 252, because the beam limiting aperture array associated with the converging lens array 231 can shape the beam waves 211, 212, 213 of the multiple beams from the source 201. The beam limiting aperture array of the converging lens can also be used as an electrode in the lens array.

[0085] The paths of the beams 211, 212, 213 diverge from the converging lens array 231. The converging lens array 231 focuses the generated beams to an intermediate focus (i.e., toward the control lens array and the objective lens array) between the converging lens array 231 and the objective lens array assembly 241. The collimator array 271 may be located at the intermediate focus, rather than being associated with the objective lens array assembly 241.

[0086] The collimator can reduce the divergence of the divergent beam path. The collimator can collimate the divergent beam paths so that they are substantially parallel toward the objective array assembly. The corrector array can be present in the multi-beam path, for example associated with the converging lens array, the intermediate focus, and the objective array assembly. The detector 240 can be integrated into the objective 241. The detector 240 can be located on the bottom surface of the objective 241 so as to face the sample during use.

[0087] In an embodiment, the detector may be integrated into the electron-optical assembly 700. In an embodiment, the detector 240 is associated with or even integrated into the plates 710, 720 of the electron-optical assembly 700. For example, the detector 240 may be located on the bottom surface of the electron-optical assembly 700 including the objective lens 241. The detector 240 may be provided with electrical connections 60 as described elsewhere in this document.

[0088] The electron optical device array may have multiple multi-beam devices of this design, as shown in FIG. Figure 4 shown Figure 3 Such an arrangement is shown and described in EP application 20158732.6 filed on February 21, 2020, which relates to a multi-device arrangement of a multi-beam tool with a collimator at an intermediate focus characterized by the design of the disclosed multi-beam device, which application is incorporated herein by reference.

[0089] Yet another alternative design of a multi-beam tool includes multiple single-beam devices. A single beam generated for the purposes of the invention described herein may be similar to or equivalent to a multi-beam generated by a single device. Such a multi-device tool may have one hundred devices, each generating a single beam or beam wave. In such other alternative designs, the single-beam devices may have a common vacuum system, each device may have a separate vacuum system, or a group of devices may be assigned different vacuum systems. Each device may have an associated detector.

[0090] The electron optics 40 may be part of an inspection (or metro inspection) tool or part of an electron beam lithography tool.Multi-beam charged particle devices may be used for many different applications, including electron microscopy in general, not just scanning electron microscopy, and lithography.

[0091] The electron optical axis 304 describes the path of charged particles through the source 201 and output from the source 201. Unless explicitly mentioned, the beamlets and beamlets of the multibeam can be substantially parallel to the electron optical axis 304 at least through the manipulator or the electron optical array. The electron optical axis 304 can be the same as or different from the mechanical axis of the electron optical device 40.

[0092] The electronic optical device 40 may include Figure 6 The electron optical assembly 700 shown is used to manipulate electron beam waves. For example, the objective lens array 241 and / or the focusing lens array 231 may include the electron optical assembly 700. In particular, the objective lens 331 and / or the focusing lens 310 and / or the control lens 250 may include the electron optical assembly 700.

[0093] Electro-optical components are configured to provide a potential difference between two or more plates (or substrates). An electrostatic field is generated between the plates acting as electrodes. The electrostatic field generates an attractive force between the two plates. The attractive force can increase as the potential difference increases.

[0094] In an electron optical assembly, at least one plate has a stepped thickness so that the array plate is thinner in a region corresponding to an aperture array than in another region of the array plate. Having a stepped thickness is advantageous, for example two portions of a plate have different thicknesses, because at high potential differences the plate is subject to higher electrostatic forces, which may result in bending if the plate is of uniform thickness and is, for example, too thin. Bending of the plate may adversely affect beam-to-beam uniformity. Therefore, a thick plate is advantageous in mitigating bending. However, if the plate is too thick in the region of the aperture array, this may result in undesirable electron beam wave deformation. Therefore, a thin plate surrounding the aperture array is advantageous in mitigating electron beam wave deformation. That is, the aperture array may be defined in a region of the plate that is thinner than the rest of the plate. Therefore, the stepped thickness of the plate reduces the likelihood of bending without increasing the likelihood of beam wave deformation.

[0095] Figure 6 The exemplary electron optical assembly shown includes an array plate 710, an adjacent plate 720, and an isolator (or spacer) 730. (Note that the term 'array plate' is a term used to distinguish this plate from other plates referenced in the description). In the array plate, an array of apertures 711 is defined for the path of the electron beam wave. The number of apertures in the aperture array can correspond to the number of beamlets in the multi-beam arrangement. In one arrangement, there are fewer apertures in the multi-beam than beamlets, so the beamlet path groups pass through the apertures. For example, the apertures can extend through the multi-beam path; the apertures can be strips or slits. The isolator 730 is disposed between the plates to separate the plates. The electron optical assembly is configured to provide a potential difference between the array plate 710 and the adjacent plate 720.

[0096] In the adjacent plate 720, another array of apertures 721 is defined for the path of the electron beam wave. The adjacent plate 720 may also have a stepped thickness so that the adjacent plate is thinner in the area corresponding to the aperture array than another area of ​​the adjacent plate. Preferably, the aperture array 721 defined in the adjacent plate 720 has the same pattern as the aperture array 711 defined in the array plate 710. In the arrangement, the pattern of the aperture arrays in the two plates may be different. For example, the number of apertures in the adjacent plate 720 may be less than or greater than the number of apertures in the array plate 710. In the arrangement, there is a single aperture in the adjacent plate for all paths of the sub-beams of the multi-beam. Preferably, the apertures in the array plate 710 and the adjacent plate 720 are substantially well aligned with each other. This alignment between the apertures is to limit lens aberrations.

[0097] The thickness of the array plate and the adjacent plate at the thickest point of the plate may each have a thickness of up to 1.5 mm, preferably 1 mm, more preferably 500 μm. In an arrangement, the thickness of the downstream plate (i.e. the plate closer to the sample) at the thickest point may be between 200 μm and 300 μm. Preferably, the thickness of the downstream plate at the thickest point is between 200 μm and 150 μm. The thickness of the upstream plate (i.e. the plate further from the sample) at the thickest point may be up to 500 μm.

[0098] The surface of the array plate between the thinner region of the plate 710 and other regions of the plate (e.g., thicker regions) (e.g., providing a step) is preferably orthogonal to the surface of the plate facing the adjacent plate 720 and / or the path of the multiple beams. Similarly, the surface of the adjacent plate 720 at the step between the thicker region (radially outward) and the inner region (radially inward) can preferably be orthogonal to the surface of the adjacent plate facing the array plate 710.

[0099] The coating may be provided on the surface of the array plate and / or the adjoining plate. Preferably, the coating is provided on both the array plate and the adjoining plate. The coating reduces surface charges which may otherwise cause unwanted beam distortions.

[0100] The coating is configured to survive an electrical breakdown event that may occur between the array plate and an adjacent plate. Preferably, a low ohmic coating is provided, and more preferably a coating of 0.5 ohm / square or less is provided. The coating is preferably provided on the surface of the downstream plate. The coating is more preferably provided between at least one plate and the separator. The low ohmic coating reduces undesirable surface charging of the plate.

[0101] The array plate and / or the adjacent plate may comprise a low bulk resistance material, preferably 1 ohm meter or less. More preferably, the array plate and / or the adjacent plate comprises doped silicon. Plates with low bulk resistance have the advantage that they are less likely to fail because the discharge current is supplied / drained via the bulk rather than, for example, via a thin coating.

[0102] The array plate includes a first wafer. The first wafer can be etched to generate regions with different thicknesses. The first wafer can be etched in regions corresponding to the aperture array so that the array plate is thinner in the regions corresponding to the aperture array. For example, a first side of the wafer can be etched, or both sides of the wafer can be etched to create a stepped thickness of the plate. The etching can be performed by deep reactive ion etching. Alternatively or additionally, the stepped thickness of the plate can be produced by laser drilling or machining.

[0103] Alternatively, the array plate may include a first wafer and a second wafer. An aperture array may be defined in the first wafer. The first wafer may be arranged to contact the isolator. The second wafer arranged on the surface of the first wafer is in an area that does not correspond to the aperture array. The first wafer and the second wafer may be joined by wafer bonding. The thickness of the array plate in the area corresponding to the aperture array may be the thickness of the first wafer. The thickness of the array plate in another area other than the aperture array area (e.g., radially outward of the aperture array) may be the combined thickness of the first wafer and the second wafer. Therefore, the array plate has a stepped thickness between the first wafer and the second wafer.

[0104] One of the array plate and the adjacent plate is in an upstream direction of the other. One of the array plate and the adjacent plate is negatively charged relative to the other plate. Preferably, the upstream plate has a higher potential than the downstream plate relative to, for example, ground potential, a source or a sample. The electron optical assembly can be configured to provide a potential difference of 5 kV or greater between the array plate and the adjacent plate. Preferably, the potential difference is 10 kV or greater. More preferably, the potential difference is 20 kV or greater.

[0105] The isolator 730 is preferably disposed between the array plate and the adjacent plate such that the opposing surfaces of the plates are coplanar with each other. The isolator 730 has an inner surface 731 facing the beam path. The isolator 730 defines an opening 732 for the path of the electron beam.

[0106] A conductive coating may be applied to the separator, such as coating 740. Preferably, a low ohmic coating is provided, and more preferably a coating of 0.5 ohms / square or less is provided.

[0107] The coating is preferably located on the surface of the space facing the negatively charged plate, which is negatively charged relative to another plate. The downstream plate is preferably negatively charged relative to the upstream plate. The coating should be at the same potential as the negatively charged plate. The coating is preferably located on the surface of the separator facing the negatively charged plate. The coating is more preferably electrically connected to the negatively charged plate. The coating can be used to fill any possible gap between the separator and the negatively charged plate.

[0108] Without this coating on the isolator, an electric field enhancement may occur in these voids. This electric field enhancement may cause electrical breakdown in these voids and, as a result, instability in the potential of the lower electrode. This potential instability causes the lens strength to vary over time, defocusing the electron beam.

[0109] The inner surface 731 is shaped so that the creep path between the plates above the inner surface is longer than the minimum distance between the plates.Preferably, the inner surface of the isolator is shaped to provide a creep length of 10 kV / mm or less, preferably 3 kV / mm or less.

[0110] Figure 6 The exemplary electron optical assembly 700 includes an isolator 730 defining an opening 732. The isolator 730 has a stepped thickness. The thickness of the isolator 730 in the isolator region closest to the electron beam wave path is less than the thickness of the isolator 730 in the region farther from the electron beam wave path. In an arrangement such as Figure 6 As depicted, the opening 732 of the isolator 730 has a larger width (which may be a diameter) on the upstream side than on the downstream side. That is, an aperture or opening is defined in the isolator, which aperture or opening may define a passage having a surface. The passage may have at least two different diameters at different positions along the beam path through the aperture. For example, the stepped surface between the passage portions having different diameters is angled and is preferably parallel to at least one of the array plate and the adjacent plate and / or orthogonal to the beam path. The surface area of ​​the isolator 730 in contact with the downstream plate 720 is larger than the surface area in contact with the upstream plate 710. In another arrangement, the width of the opening defined in the isolator on the downstream side of the isolator is greater than its upstream side. One of the upstream plate and the downstream plate is positively charged relative to the other plate. Preferably, the opening defined in the isolator has a larger width on the side of the isolator closest to the plate that is positively charged relative to the other plate.

[0111] Electron optical assembly 700 may include or be a lens assembly for manipulating electron beam waves. The lens assembly may be, for example, an objective lens assembly or a converging lens assembly, or may be a portion thereof. The lens assembly (such as an objective lens assembly) may also include an additional lens array including at least two plates, such as control lens array 250.

[0112] Figure 7 FIG. 7 is a schematic diagram of an electrical connector 60 of an exemplary electron optical assembly 700. The electron optical assembly 700 is configured to manipulate an electron beam. Figure 7 As shown, in an embodiment, the electron-optical assembly 700 includes a first electron-optical element, which includes a board 710. (Note that if the electron-optical assembly 700 includes only one first electron element, the first electron-optical element may be referred to as an electron-optical element).

[0113] In an embodiment, the electron-optical assembly 700 includes a plurality of electron-optical elements, each of which includes a plate. Figure 6The illustrated electron-optical assembly 700 includes a first electron-optical element (including a board 710) and a second electron-optical element (including another board 720). In an embodiment, the electron-optical assembly 700 includes more than two electron-optical elements, each of which includes a board. The electrical connector 60 described in this document can be applied to connect any one or each of the boards 710, 720 of the electron-optical assembly 700 to a power source (or power supply).

[0114] In an embodiment, the plate 710 has one or more apertures 711 around the beam path of the electron beam. Figure 6 As shown, in an embodiment, the plate 710 includes an aperture array 711. In an alternative embodiment, the plate 710 includes only one aperture. Each aperture 711 can be used for the beam path of a single electron beam. Alternatively, one or more apertures 711 can surround the beam paths of multiple electron beams.

[0115] Figure 7 The electrical connector 60 is schematically shown. The electrical connector 60 is configured to electrically connect the board 710 of the first electron-optical element to a power supply. In an embodiment, the electron-optical device 40 comprises the electrical connector 60. In an embodiment, the electron-optical assembly 700 comprises the electrical connector 60.

[0116] In an embodiment, the power supply is a high voltage power supply. In an embodiment, the power supply is configured to apply a voltage of at least 100V, optionally at least 200V, optionally at least 500V, optionally at least 1kV, optionally at least 2kV, optionally at least 5kV, optionally at least 10kV, and optionally at least 20kV to a portion of the electron optical assembly 700 relative to a reference potential of the electron optical device 40. In an embodiment, the power supply is configured to apply a positive voltage relative to the reference potential. In an alternative embodiment, the power supply is configured to apply a negative voltage relative to the reference potential. The reference potential can be grounded. In an embodiment, one or more of the plates 710, 720 of the electron optical assembly 700 are configured to be connected to a high voltage during use of the electron optical device 40.

[0117] like Figure 7 As shown, in an embodiment, the electrical connector 60 includes a shield 61. The shield 61 is configured to define a field-free region 62. The field-free region 62 is substantially free of an electric field. In an embodiment, the shield 61 is configured to shield the electrical components within the field-free region from external electric fields. The field-free region is field-free relative to the electrical components, desirably when within the shield 61. In an embodiment, the shield 61 is configured to reduce the possibility of electrical breakdown between the electrical components within the field-free region 62 and another component of the electronic optical device 40.

[0118] In an embodiment, the electrical connector 60 includes a flexible coupler 63. The flexible coupler 63 is an electrical component. The flexible coupler 63 is conductive. The flexible coupler is configured to electrically connect the electrical connector 60. The flexible coupler is configured to electrically connect the electrical connector to a cable 64. The cable 64 is connected to a power source. The flexible coupler enables the electrical connector to be electrically connected to the cable 64. The flexible coupler can be located in an electrical path between a plate 710 and a power source. In an embodiment, the flexible coupler 63 is configured to electrically connect the plate 710 to a power source, such as thereby enabling the electrical connector 60 to connect the plate 710 to a power source. The plate 710 can be electrically connected to the power source via the flexible coupler 63. Therefore, the plate 710 can be electrically connected to the cable by the power source. The electrical path can include: a cable 64, an electrical connector 60 including, for example, a flexible connector 63, and a plate 710.

[0119] like Figure 7 As shown, in an embodiment, the flexible coupler 63 is located within the field-free region 62 defined by the shield 61. The flexible coupler 63 is intended to provide an electrical connection to the board 710, for example, via an electrical connection to an electrical conductor such as the shield 61. The flexible coupler extends from the radially outer side of the board 710. The shield 61 is configured to shield the flexible coupler 63 from the electric field outside the shield 61. Embodiments of the present invention are expected to reduce the possibility of electrical breakdown associated with the (electrical) connection of the electronic optical device to a power source, for example, between the electrical connector 60 and another component of the electronic optical device 40 (for example, another component of the electronic optical assembly 700). The flexible coupler can be considered as a plug or male part; the shield 61 can be considered to provide a field-free region in which the flexible coupler can be electrically connected to the board 710. In an embodiment, the shield 61 can be considered as a part of a socket (or male part) or at least a part of a socket (or male part) for electrical and physical engagement with an insert part such as a plug (for example, a flexible coupler). That is, the flexible coupling may be a male part such as a plug. The shield 61 may be a female part such as a socket. The male part and the female part may be removably engaged with each other.

[0120] During the process of using the electron-optical device 40, some electrostatic discharges may occur. Embodiments of the present invention are expected to: reduce the magnitude of any such discharges; and / or reduce the destructiveness that any such discharges may have. Small non-destructive discharges may occur while the electron-optical device 40 continues to perform its function as expected within the specification range of one or more performance parameters. One or more performance parameters are related to aberrations, such as geometric aberrations of the electron-optical device 40. One possible performance parameter is alignment. The alignment may have a specification range, namely, the electron-optical element is parallel and flat in a direction across (e.g., orthogonal to) the beam path, with a tolerance of up to 100nm to 10μm. Another possible performance parameter is axial misalignment (i.e., misalignment of the electron-optical element in a direction parallel to the beam path). Axial misalignment may have a specification range where the electron-optical element is positioned along the electron-optical axis within a tolerance of up to 50nm to 500nm.

[0121] The flexibility of flexible coupling 63 reduces the possibility that electrical connector 60 undesirably affects the position and / or formation (e.g., shape) of plate 710. This flexible coupling being connected to an electronic optical device can reduce the risk that force and / or moment are applied to the electronic optical device. During device operation, applying this force or moment may undesirably affect the electronic optical performance of the electronic optical device. This influence of the performance of the electronic optical device can be observed from, for example, the position of the device, thereby can be observed from the alignment and other aberrations of the device relative to one or more charged particle beams and between the charged particle beams. This aberration may be caused by, for example, stress variations in the device and / or the formation of the device, such as by the deformation of the element shape of the device, causing field distortion generated in the device.

[0122] Embodiments of the present invention are expected to allow for more accurate positioning of the electron-optical assembly 700. Embodiments of the present invention are expected to reduce the forces and / or moments applied to the electron-optical assembly 700 by the electrical connector 60. Embodiments of the present invention are expected to reduce any undesirable deformation of the electron-optical assembly 700 by the electrical connector 60. For example, the flexibility of the flexible coupler 63 can reduce the likelihood of deformation of the plate 710, thereby reducing flatness (or deforming the plate away from a planar element). It is expected that the plate 710 will be aligned with other components and / or the electron beam of the electron-optical device 40. Embodiments of the present invention are expected to improve the alignment accuracy of the plate 710. Therefore, in a non-limiting list, the performance parameters can be: alignment accuracy of the plate, for example relative to one or more charged particle beams, plate flatness, and / or degree of deformation.

[0123] like Figure 7As shown, in an embodiment, the electrical connector 60 includes a cable 64. The cable 64 is configured to electrically connect the flexible coupling 63 to a power source. In an embodiment, the cable 64 includes an insulator 65 surrounding a conductor 66. The conductor 66 is a transmission line. The insulator 65 is configured to insulate the conductor 66 from the environment.

[0124] In an embodiment, the cable 64 is a conductive cable (e.g., a coaxial cable) without an external insulator 65 (e.g., an external shield). The outer surface of the portion of the cable without the insulator is the conductive surface of the conductor 66. In the arrangement, the outer shield of the cable 64 has been removed, at least near the flexible coupler, to expose the conductive surface. Removing the outer shield can allow for a greater creep distance on the insulator 65 of the cable 64. By increasing the creep distance, the likelihood of electrons being conductive by creeping over the surface of the insulator 65 can be reduced. For example, if Figure 7 As shown, in an embodiment, an isolated section of the cable 64 (e.g., an outer shield or insulator 65) is located in the field-free region 62; that is, the insulator 65 extends into the field-free region until the end of the cable 64. The surface of the conductor 66 within the cable is provided only at the surface of the cable at the end of the cable 64. In a different embodiment, the outer shield of the cable 64 extends into the field-free region 62, shorter than the end of the cable, so that a portion of the conductor provides the outer surface of the cable 64 between the end of the cable 64 and the insulator 65. This portion of the conductor is completely within the field-free region 62. The conductor 66 of the cable 64 is exposed only within the field-free region 62. This reduces the possibility of electrical breakdown between the conductor 66 of the cable 64 and another component of the electronic optical device 40.

[0125] In an embodiment, the flexible coupling 63 is more flexible in at least one degree of freedom, optionally at least two degrees of freedom, and optionally all degrees of freedom than the cable 64. The flexible coupling 63 is configured to provide a lower stiffness connection with the board 710 (and / or any other board of the electronic-optical assembly 700), optionally at high voltages.

[0126] The cable 64 may be relatively rigid. Figure 7 As shown, in an embodiment, the cable 64 is mechanically connected to the board 710 only via a relatively low stiffness component (e.g., a flexible coupler 63). In an embodiment, the cable 64 includes a flexible coupler 63. The cable 64 is not mechanically directly attached to a board of the electronic optical assembly 700, such as a first board 710 and a second board 720 (which may be an upstream board 710 and a downstream board 720, respectively) and / or an isolator 750, 760. The isolators may be referred to as a first isolator 750 and a second isolator 760, which may be referred to as an upstream isolator 750 and a downstream isolator 760, respectively. The isolator 750 has an outward periphery 72. Regarding Fig. 9Features related to the outward periphery 72 of the isolator 750 are described in more detail. The diameter of the cable 64 can be at least 0.1 mm, optionally at least 0.5 mm, optionally at least 1 mm and optionally at least 2 mm. The diameter of the cable 64 can be at most 5 mm. The stiffness of the cable 64 can be at least 10000 N / m. The stiffness of the cable 64 can be at most 100000 N / m. In an embodiment, the end 69 of the cable 64 is electrically connected to the shield 61 when electrically connected to the board 710. In an embodiment, the shield 61 is an electrical conductor through which the cable 64 is electrically connected to the board 710. For example, if the cable 64 has no electrical insulation or insufficient electrical insulation, and / or if the diameter of the cable 64 is less than a threshold value, a portion of the cable 64 that is electrically connected to the shield 61 and extends away from the field-free region 62 is at risk of discharge within the vacuum of the device. The restriction on the diameter of the cable 64 limits the flexibility of the cable 64. The requirement that the diameter of the cable 64 has a lower limit requires that the cable have a certain rigidity, and if the cable is directly connected to the electron-optical assembly 700, there is a risk of applying force and / or torque to the electron-optical assembly 700. Therefore, it is not desirable to directly connect the cable 64 to the electron-optical assembly 700 or to increase the flexibility of the cable 64 itself.

[0127] like Figure 7 As shown, the shield 61 and the plate 710 may be connected to each other via the connection surface 67, such as a planar portion of the connection surface. Fig.13 The features of the connection surface 67 are described in more detail. In an embodiment, the flexible coupler 63 is connected to the shield 61 at a connection point 68. In such an embodiment, the flexible coupler is secured to the shield 61 and can be connected to the cable 64. For example, in an embodiment, the flexible coupler 63 is welded to the shield 61 at the connection point 68.

[0128] In an embodiment, the flexible coupler 63 includes wiring. The flexible coupler 63 can be an insertion component, such as a plug. In an embodiment, the flexible coupler 63 is made of a metal such as copper or bronze, such as phosphor bronze. In an embodiment, the flexible coupler 63 has a diameter of up to 500 μm, optionally up to 200 μm, optionally up to 100 μm, and optionally up to 50 μm. In an embodiment, the stiffness of the flexible coupler 63 is up to 10 N / m, optionally up to 5 N / m, optionally up to 2 N / m, and optionally up to 1 N / m. A thinner flexible coupler 63 can have a lower stiffness. During use of the electronic optical component 700, the flexible coupler 63 can be at a high voltage. The flexible coupler 63 is located in the field-free region 62 to reduce potential problems of discharge or partial discharge. The flexible coupling 63 is thus connected to the same potential as the cable 64 , although it is more flexible since it is completely contained within the field-free area 62 ; the risk of discharges associated with the connection of the cable 64 to the electro-optical assembly, if not prevented by the use of a flexible coupling, is significantly reduced.

[0129] The shield 61 (which may be an example of a receiving component such as a socket) includes one or more surfaces 611 defining a field-free region 62. The one or more surfaces 611 defining the field-free region 62 may be at substantially the same potential difference (e.g., voltage) as the flexible coupler 63. Thus, the field-free region defined by the shield 61 is field-free relative to the flexible coupler 63. In an arrangement with multiple surfaces 611, different surfaces 611 may face different directions so as to define a groove. The groove may be defined by a continuous surface, and different regions of the continuous surface may face different directions. One or more of the surfaces 611 of the shield 61 may be mechanically connected and electrically connected to the flexible coupler 63. In an alternative embodiment, the surface 611 of the shield 61 may be electrically connected to a power source other than the flexible coupler 63. There may be substantially no potential difference between the flexible coupler 63 located within the field-free region 62 and the surface 611 of the shield 61 defining the field-free region 62. Thus, the field-free region defined by the surface 611 of the shield 61 is field-free relative to the flexible coupler 63. It is possible that some potential difference may exist. In an embodiment, the potential difference is small enough that the likelihood of electrical breakdown between the flexible coupling 63 and the shield 61 is negligible. Any such electrical breakdown is small enough that no damage is caused.

[0130] In an embodiment, the shield 61 comprises a conductive material. The shield may be composed of a conductive material, for example, the shield may be solid. In an embodiment, the outer surface of the shield 61 is at substantially the same electrical potential as one or more surfaces 611 defining the field-free region 62. The field-free region 62 may be within a groove defined by one or more surfaces 611. One or more different surfaces (e.g., defining a groove) may define a shielding effect that provides the field-free region 62. Figure 7 As shown, in an embodiment, the outer surface of the shield 61 includes one or more rounded curves or corners 73. The outer surface of the shield can be a smooth continuous surface, such as without clearly defined edges or corners. Embodiments of the present invention are expected to reduce the possibility of electrical breakdown between the shield 61 and another component of the electronic optical device 40.

[0131] In an embodiment, the length (e.g., depth) of the field-free region 62 is at least as large as the diameter of the field-free region 62. In an embodiment, the length of the field-free region 62 is at least twice the diameter of the field-free region 62, and optionally at least five times. In general, charges on the isolator surface at least five times the gap size away from the electric field source may not matter. This may be referred to as the 1:5 rule. In order for the field-free region 62 to be substantially free of an electric field, it is expected that the field-free region 62 does not need to have a depth that follows the 1:5 rule.

[0132] In an embodiment, at least a portion of the shield 61 overlaps the plate 710 when viewed perpendicular to the plane across the beam path. In an embodiment, at least a portion of the shield 61 overlaps the plate 710 when viewed in a direction perpendicular to the plane of the plate 710. Figure 7 As shown, in an embodiment, when viewed in a direction perpendicular to the plane of the plate 710, the shield 61 substantially entirely overlaps the plate 710. It is not necessary to completely overlap. Figures 8 to 13 As shown, in an embodiment, the shield 61 only partially overlaps the board 710 when viewed in a direction perpendicular to the plane of the board 710. Any overlap may help provide a secure electrical connection between the board 710 and the shield 61, such as Figure 7 As depicted, or providing a secure electrical connection between the plate 710 and the flexible coupling 63 located within the field-free region 62 (see, for example, Figure 8 ).

[0133] like Figure 7 As shown, in an embodiment, the portion of the shield 61 that overlaps the plate 710 is located only at one of the upstream side and the downstream side of the plate 710. For example, in an embodiment, Figure 7 The orientation of the electron-optical assembly 700 is shown in FIG. Figures 2 to 5 The orientation of the electron-optical devices shown is the same. Figure 7The upper side of the electron optical component 700 in the figure is the upstream side. The downstream side is located at Figure 7 The electron optical assembly 700 is shown below. Figure 7 As shown, in an embodiment, the overlapping portion of shield 61 is located only on the upstream side of plate 710. Shield 61 has no distance contribution to the extent that electron-optical assembly 700 extends in the downstream direction. Embodiments of the present invention enable electron-optical assembly 700 to be connected to a high voltage within the spatial constraints of electron-optical device 40.

[0134] In an embodiment, the electron-optical assembly 700 may be positioned near the sample 208. For example, the electron-optical assembly 700 may be an electron-optical lens assembly, such as an objective lens assembly, close to the sample 208. The shield 61 does not affect the position of the electron-optical assembly 700 relative to the sample 208.

[0135] In an alternative embodiment, the portion of shield 61 that overlaps plate 710 may be located only on the downstream side of plate 710. In an embodiment, electron-optical assembly 700 may be positioned close to another electron-optical component located in an upstream direction of electron-optical assembly 700. Shield 61 may be positioned relative to the remainder of electron-optical assembly 700 so that electron-optical assembly 700 may be freely positioned relative to upstream electron-optical components, for example, to meet electron-optical requirements. That is, shield 61 may be positioned relative to electron-optical assembly 700 so as not to affect the position of electron-optical assembly 700 relative to upstream electron-optical components.

[0136] like Figure 7 As shown, in an embodiment, the board 710 is configured to be electrically connected to the flexible coupler 63 via the shield 61. The shield 61 is located in the middle between the flexible coupler 63 and the board 710 along the electrical path. The shield 61 can be positioned only on one side of the board 710. This can reduce the amount of space occupied by the shield 61 in the direction of the electron beam path. This arrangement can avoid additional electrical paths to the shield that are separate from the connection of the cable 64 to the electron optical assembly 700, such as from at least Figure 8 and Fig.11 This can be apparent from the description of the arrangement.

[0137] The board 710 may be electrically connected to the flexible coupling 63 without necessarily being connected via the shield 61. In an alternative embodiment, the board 710 is directly connected to the flexible coupling 63 (see, for example, Fig.11 ) or connected to the flexible coupling 63 via another component other than the shielding member 61.

[0138] like Figure 7As shown, in an embodiment, the shield 61 is mechanically fixed relative to the board 710 by a mechanical connection. The shield 61 is reliably and stably attached relative to the board 710. The shield 61 can be included as a part of the electronic optical component 700. In an embodiment, the shield 61 is directly mechanically attached to the board 710. Such a directly connected shield can be an electrical conductor. For example, the shield 61 can be connected to the board 710 by a conductive adhesive and / or a conductive weld. In an alternative embodiment or another embodiment, the shield 61 can be mechanically connected to the board 710 via an intermediate mechanical member. In an embodiment, the shield 61 and the board 710 are electrically connected to each other via a mechanical connection, for example, via a conductive layer on one or more isolators in the upstream or downstream direction of the board 710, such as a metal layer and / or a coating.

[0139] As mentioned above, in an embodiment, the connection between the shield 61 and the plate 71 is achieved by directly adhering (e.g., gluing) the shield 61 to the plate 710 with a conductive adhesive. In an alternative embodiment, the shield 61 can be adhered to a conductive trace on one of the separators 760 adjacent to the plate 710. The conductive trace can be an intermediate member between the plate 710 and the shield 61 for electrical connection. The conductive trace can provide at least a portion of the conductive layer and can be a member such as a layer (e.g., a coating). In this arrangement, the surface of the separator 760 and the shield can be secured to each other. The plate 710 (e.g., toward the edge or outer region of the plate 710) can be secured to the inward (or radially inward) portion of the surface of the separator 750. The plate 710 (e.g., the outer region, such as the edge) can be located between adjacent separators, such as the separator 760 and the adjacent separator 750. The outer edge of the plate 710 can be located radially inward of one or two of the adjacent separators. The conductive traces extend at least between the outer edge of the plate 710 and the shield 61 (e.g., the inner region of the shield 61). The conductive traces may extend between a portion of the isolator 760 and a portion of the plate 710, and / or between an outer portion of the insulator 760 and an inner portion of the shield 61 (i.e., directed toward the outer portion of the isolator 760). In an arrangement, the plate 710 may extend further outward than either isolator (e.g., relative to an inward portion of the plate 712); and the conductive traces extend at least between the outer edge of the plate 710 and the shield 61. Similar variations may exist for arrangements in which the plate 710 extends radially inward of two adjacent isolators 750, 760. The details of the conductive traces described with reference to the isolator 760 may additionally or alternatively apply to conductive traces applied to adjacent isolators 750, as long as electrical contact can be achieved between adjacent isolators 750 and the shield 61. The use of conductive traces may be beneficial in ensuring that the plate 710 is sufficiently flat during operation. The use of a coating ensures that any forces applied to the shield 61 are decoupled from the board 710, such as might occur if the shield were secured directly to the board 710. Forces applied to the board 710 (such as a direct physical connection) may affect the flatness of the board 710. Even small applied forces may have an effect on the height (i.e., flatness) of the board 710 (i.e., the electrode) and its electro-optical function. The use of conductive traces (such as a coating) reduces the transmission of such distorting forces to the board, if this cannot be prevented.

[0140] like Figures 6 to 15As shown, in an embodiment, the electron optical assembly 700 includes at least one isolator 750, 760 adjacent to the plate 710. The isolator is configured to electrically isolate the plate 710 from one or more other plates of the electron optical assembly 700 and / or one or more other components of the electron optical device 40. In an embodiment, the isolators 750, 760 are mechanically connected to the plate 710. In an embodiment, the isolators 750, 760 are configured to mechanically isolate the plate 710 from one or more other plates of the electron optical assembly 700. When the electron optical assembly 700 is located in the electron optical device 40, one of the isolators 750, 760 can be positioned in an upstream direction of the other isolator.

[0141] In an embodiment, the isolators are substantially planar. The isolators 750, 760 and one or more plates may be included in a stack within the electron-optical assembly 700. In an embodiment, the isolators are substantially parallel to the plate 710.

[0142] like Figure 7 As shown, the stack of electron optical components includes a protruding element. The protruding element may include a protruding plate portion and / or a protruding isolator portion of the plate 710. In an embodiment, as depicted, the downstream isolator 760 includes a protruding isolator portion. In an embodiment, the plate 710 includes a protrusion 713 (or a protruding plate portion); that is, the protrusion is a part of the plate 710. Alternatively, the protrusion 713 is a separate conductive planar piece connected to the plate 710. The outward periphery of the stack is defined by one or more isolators 750, 760 and one or more plates, which have a common outward dimension in a plane orthogonal to the beam path, such as in each of the primary axes of the plane orthogonal to the beam path or in a radially outward direction. The protrusion 713 extends beyond the outward periphery. In an embodiment, the protrusion 713 thus protrudes beyond the radially outward periphery of the upstream isolator 750 (e.g., the stack) relative to the beam path. In an embodiment, when viewed in a direction perpendicular to the plane of the plate 710, the protrusion 713 protrudes beyond the radially outward periphery of the isolator 750. Desirably, the shield 61 is secured to the protrusion 713. Desirably, the protrusion 713 is shaped to correspond to the contact surface of the shield, desirably located in a plane that is desirably orthogonal to the beam path.

[0143] In an embodiment, the electrical path is via a conductive element on the surface of the downstream isolator 760, which is expected to protrude further outward from the path of the multiple charged particle beams. Note that the downstream isolator 750 can be considered to include a portion of a protruding element, such as a protruding isolator portion. Such a protruding isolator portion can be a portion of the periphery of the protruding isolation portion of the downstream isolator. (In different embodiments, the upstream isolator 750 includes a protruding isolation portion, and optionally, the downstream isolator does not include a portion of the protruding element.) In an embodiment where the plate 710 does not include a protruding plate portion, the protruding element can include a protruding conductor portion. The protruding conductor portion is a conductive layer (e.g., a trace) on the protruding isolator portion of the corresponding isolator 750, 760. This layer is directly or even electrically connected to the plate 710 via different conductive elements. In such an embodiment, the protruding conductor portion can be considered to be a protrusion 713. In this arrangement, even if the plate does not extend further outward to the outward periphery of the stack, such as extending outward to the upstream isolator 750, the plate will not protrude as, for example, the protruding isolation portion of the downstream isolator 760.

[0144] like Figure 7 As shown, in an embodiment, one of the isolators 750, 760 (e.g., the downstream isolator 760) can extend radially outward beyond the protrusion 713. The downstream isolator 760 can be configured to electrically isolate the protrusion 713 of the plate 710 or the conductive layer that can replace the plate 710 as part of the protruding element from the components on the other side of the isolator 760. It is desirable to expose as little of the conductive plate 710 or the conductive layer as possible to reduce the possibility of undesired electrical breakdown. The protrusion 713 extends radially beyond the other isolator 750 (e.g., the downstream isolator 760). Figure 7 750) in the orientation shown to allow electrical connection of the plate 710. In an embodiment, the protrusion 713 is formed integrally with the plate 710. In an embodiment, the protrusion 713 is a sheet, tab or fold at the edge of the plate 710. The sheet, tab or fold may extend to the inward periphery of the isolators 750, 760. In an embodiment, the protrusion has a curved radially outward periphery when viewed along the beam path. Alternatively or additionally, the protrusion 713 may have a rectangular shape when viewed along the beam path.

[0145] The protrusion 713 is configured to electrically connect the plate 710 to the power supply. In an embodiment, the radially inward portion 712 of the plate 710 can be electrically connected to the flexible coupler 63 via the protrusion 713. The radially inward portion 712 is located within the outward periphery of the isolator 750, and the protrusion 713 protrudes beyond the outward periphery. The protrusion can be located in the electrical path between the plate 710 and the power supply. In an embodiment, the protrusion 713 is a portion of the plate 710 or a portion that is electrically in contact with the plate 710 (for example, if the protrusion is a conductive layer on one of the isolators 750, 760), which provides an electrical connection. In an embodiment, the protrusion 713 is shaped into a shape corresponding to at least a portion of the shield 61, such as a conductor, in a plane that is orthogonal to the beam path as desired. For example, the protrusion 713 can be shaped to have a shape similar to the surface of the contact protrusion 713 of the shield 61.

[0146] like Fig. 9 As shown, in the embodiment, the radially inward section 712 of the plate 710 is exposed through the aperture in the isolator 750, 760. (Note that only the upstream isolator 750 is shown in this figure. Unless otherwise specified, the features of the upstream and downstream isolators are the same. The edges of the aperture define the inward periphery of the isolator 750, 760. Fig. 9 An arrangement is shown where the aperture is circular. A circular aperture helps control the effect of the electric field on the system, for example due to the symmetrical shape of the aperture. Other shapes are possible, but may be less desirable. Generally, smoother shapes (e.g., with rounded corners) are more desirable. Rounded corners and fewer corners help reduce concentrations of the electric field that would otherwise appear at sharp corners.

[0147] As mentioned above, in an embodiment, the flexible coupling 63 comprises a wire. In an embodiment, the wire 63 extends along an elongated direction. In an embodiment, the wire comprises one or more bends, for example due to flexure of the wire. When the wire comprises one or more bends, the wire may generally extend along an elongated direction, for example along an elongated dimension. For example, this Figure 7 and Figure 8 As shown. The flexible coupler 63 need not include wiring. In an alternative embodiment, the flexible coupler 63 includes a flexible electrical connector, such as a flexible printed circuit. It is desirable that the flexible coupler 63 is sufficiently flexible so that the flexible coupler deforms (e.g., flexes) in response to an applied force, rather than applying a force when a force is applied to the electronic optical assembly 700.

[0148] like Figure 7 As shown, in an embodiment, when viewed in at least one direction in a reference frame of, for example, the device 40, the shield 61 is arranged to surround the flexible coupling 63. For example, when viewed in a direction across the beam path (i.e., a direction within the plane of the plate 710), the shield 61 is arranged to surround the flexible coupling 63. Figure 7In the arrangement shown, the shield 61 surrounds the flexible coupling 63. The shield 61 protects the flexible coupling 63 from electrical discharges, such as electrical breakdown, to external parts such as the electrical connector 60 of the electro-optical assembly or even the electro-optical device 40.

[0149] In an embodiment, the shield 61 defines a groove that is configured to accommodate the flexible coupler 63. In an embodiment, the groove corresponds to the field-free region 62 and can therefore define the field-free region 62. The shield 61 is configured (e.g., shaped) to accommodate the flexible coupler 63. Thus, the field-free region defined by the groove is field-free relative to the flexible coupler 63. In an embodiment, the shield 61 can be a conductor in which the groove is defined. The aperture of the groove is defined in a surface of the conductor, such as a side surface of the conductor. The side surface can be orthogonal to the orientation of the plate and can have a common direction with the beam path. The groove can be cylindrical. The aperture of the groove can have a shape corresponding to the cross-section of the groove (e.g., a cylinder). The flexible coupler can be positioned within the groove such that the elongated dimension of the flexible coupler 63 is along the axis of the groove (e.g., a cylinder). Therefore, the shield 61 can be considered to provide the shape of the inner surface of the container for the groove (in Figure 7 On one side in the orientation shown). In an embodiment, the groove has a generally circular cross-section. The aperture of the groove may be circular. In an embodiment, the flexible coupler 63 is located at the center of the groove, for example, the elongated dimension of the flexible coupler extends in the center of the groove. The groove does not necessarily have a circular cross-section. In alternative embodiments, the groove may have a cross-section of any shape, such as a square, rectangular or hexagonal cross-section. However, for manufacturing reasons, a circular cross-section of the groove may be preferred, otherwise having a smooth curved surface, avoiding sharp edges that may present a risk of unnecessary discharge; therefore the cross-sectional shape desirably has few corners and / or rounded corners. The cross-section of the groove may be orthogonal to the depth of the groove (i.e., the length direction).

[0150] In an embodiment, the groove is configured to have a surface that is concentric with the elongation direction of the flexible coupler 63. The flexible coupler 63 can be positioned so that it maintains a certain distance from the surface of the shield 61 (e.g., the surface 611 of the groove defining the field-free region 62) (except when the flexible coupler 63 is connected to the shield 61).

[0151] Figure 8 is a schematic diagram of an electrical connector 60 in an exemplary electronic optical assembly 700. Unless expressly stated to the contrary, the features of the electrical connector 60 and the exemplary electronic optical assembly may be the same as those of Figure 7 Shown and referenced Figure 7 The arrangement described is the same or similar. Figure 8Shield 61 need not be arranged around flexible coupler 63 as illustrated in the illustrated arrangement. In an alternative embodiment, shield 61 comprises two planar members 70 defining a field-free region 62 between them. In an embodiment, planar members 70 extend substantially parallel to plate 710. In an embodiment, planar members 70 are positioned on either side of plate 710, for example in the direction of the beam path. Protrusion 713 of plate 710 is located between planar members 70 of shield 61. Protrusion 713 is shaped to correspond to the shape of shield 61 in a plane desirably orthogonal to the beam path. Desirably, the size of the shield should be larger than the protrusion.

[0152] In an embodiment, the length (e.g., depth) of the field-free region 62 is at least as large as the size of the gap between the planar members 70. In an embodiment, the length of the field-free region 62 is at least twice the size of the gap between the planar members 70, and optionally at least five times the size. Typically, the charge on the isolator surface at least five times the size of the gap from the electric field source may not matter. This may be referred to as the 1:5 rule. In order for the field-free region 62 to be substantially free of an electric field, it is expected that the field-free region 62 does not need to have a depth that follows the 1:5 rule.

[0153] like Figure 8 As shown, in an embodiment, the plate 710 is located between two isolators 750, 760, one of which may be in an upstream direction of the other isolator. In an embodiment, the isolators are substantially planar, so the plate 710 can be considered to be sandwiched between the two isolators 750, 760. In an embodiment, the isolators 750, 760 include a dielectric material such as glass or quartz. A portion of the surface of the plate 710 is covered by the dielectric material of the isolators 750, 760, for example, in contact therewith. The radially inward portion 712 is exposed and is used for the passage of the electron beam. The edge of the protrusion 713 remains exposed (i.e., uncovered) to allow the plate 710 (or the conductive layer) to be electrically connected, for example, to the flexible coupler 63. It is noted that the use of conductive traces on the isolators 750, 760 can be used to electrically connect the plate 710 to a power source (such as the flexible coupler 63), for example as combined Figure 7 Described and illustrated.

[0154] Fig.10 yes Figure 8 1 is a cross-sectional view of an embodiment of the electrical connector 60 shown. When viewed along the elongated dimension of the flexible coupling 63, Fig.10 is along the electrical connector, for example Figure 8 The cross-sectional view is taken along the line CC shown. Fig.10As shown, in an embodiment, the separators 750, 760 have a larger size than the plate 710 in the direction through the electron beam. In an embodiment, a dielectric 714 is provided at the subsurface of the plate 710 between the separators 750, 760; that is, the dielectric can be positioned on the side of the plate, for example, for covering the subsurface of the plate 710. In an embodiment, the dielectric 714 includes an adhesive. In an embodiment, the dielectric 714 includes a material that hardens when cured (for example, when subjected to UV radiation). In an embodiment, the dielectric includes an adhesive or an epoxy resin. In an embodiment, the dielectric 714 is formed by capillary filling of the gap (for example, a lateral gap) around the outward periphery of the plate 710 between the separators 750, 760. In an embodiment, the material forming the dielectric 714 is of low viscosity to help fill the gap. Desirably, the filling of the lateral gap is completed so that the lateral gap is filled by the dielectric. Therefore, desirably, the dielectric has no gaps that may become a source of electrical breakdown. Dielectric 714 is configured to electrically isolate board 710 from external components of the electron-optical assembly of electron-optical device 40 and other components of the electron-optical assembly.

[0155] In an embodiment, the dielectric 714 comprises an epoxy adhesive. In an embodiment, the adhesive is UV curable. It is desirable that the dielectric 714 has relatively low outgassing after curing, which, for example, could otherwise be a source of voids within the dielectric. Such dielectric materials may be applied to other surfaces of the board 710 that might otherwise be undesirably exposed. For example, any portion of the board 710 that is not covered by the shield 61 or isolator radially outward of the isolator relative to the beam path may have such a protective layer, such as a coating.

[0156] In an embodiment, the only exposed (or uncovered) portions of plate 710 are radially inward portion 712 and a portion of protrusion 713. In a different embodiment, the only exposed portion of the plate is radially inward portion 712. Protrusion 713 may be exposed, but it is a conductive layer that protrudes above the isolator portion and is in electrical contact with plate 710. Figure 8 and Fig.10 As shown, in an embodiment, the protrusion 713 is located within the field-free region 62. The planar member of the shield 61 extends further inward than the outward periphery of the stack. The planar shield extends further outward than the protrusion 713. The width of the protrusion is less than the width of the shield. The surface 611 (or facing surface) of the shield facing the protrusion 713 defines the field-free region 62. In practice, within the electrical connector 60, it is desirable that the exposed (or uncovered) portion of the flexible coupler and the protruding conductive portion (or protrusion 713, i.e., the plate 710 or a conductive layer in electrical contact with the plate 710) is located within the field-free region 72. Such a field-free region greatly reduces, if not prevented, exposure of components within the field-free region to external electric fields.

[0157] As mentioned above, the surface of the board 710 may be covered by a dielectric material such as spacers 750, 760 and dielectric 714. This helps to reduce and / or shape the electric field near the edge of the board 710. The use of such dielectric materials can further improve the field-free region and reduce exposure to external fields within the field-free region.

[0158] Fig.10 is a schematic diagram of an electrical connector 60 in an exemplary electronic optical assembly 700. Unless expressly stated to the contrary, Figure 8 and Fig.10 (as well as Figure 7 ) and reference Figure 8 and Fig.10 (as well as Figure 7 ) may be applicable to the description of the electrical connector 60 and the electronic optical assembly described in the foregoing. Fig.11 As shown, in an embodiment, the spacers 750, 760 are thicker than the planar member 70 of the shield 61. The dimensions of the spacers 750, 760 in the direction along the electron beam are larger than the dimensions of the planar member 70 of the shield 71. In an embodiment, the planar member 70 is in mechanical contact with the spacers 750, 760. In an embodiment, the flexible coupler 63 is electrically connected to the planar member 70 of the shield 61.

[0159] As mentioned above, in an embodiment, the plate 710 includes a protrusion 713 that protrudes beyond the outward perimeter of the separator 750. (See, e.g., Fig.11 . ) In an alternative embodiment, protrusion 713 is not required. The outward perimeters of the spacers 750, 760 on either side of the plate 710 may extend beyond the outward perimeter of the plate 710. (This arrangement is not depicted in cross-section; this arrangement may be employed Figure 8 , Fig.10 and Fig.11 Shown and referenced Figure 8 , Fig.10 and Fig.11 70, except that the outward periphery of the separators is outside the outward periphery of the plate 710.) For example, when the separators 750, 760 are thicker than the planar member 70 of the shield 61 (e.g., as Fig.11 ), then the planar member 70 may be arranged to overlap the plate 710 within the footprint of the stack, for example when considered in a plane orthogonal to the direction of the beam path. Fig. 9 As shown. (Note that considering Figure 8 The cross section CC in Fig. 9 right Figure 8 , Fig.10 and Fig.11 Shown and relative to Figure 8 , Fig.10and Fig.11 The application of the described embodiments may vary; therefore, Fig. 9 are referenced with respect to different embodiments. ) Fig. 9 An embodiment within the scope of the disclosure is a plan view of an electrical connector 60 of an exemplary electronic optical assembly 700 in which a plate 710 is recessed into the stack and recessed relative to the outward perimeter of the isolator. Fig. 9 As shown, in an embodiment, the planar member 70 of the shield 61 extends inwardly, for example toward the path of the beam, through the outward perimeter 72 of the isolator 750. The planar member of the shield 61 desirably extends inwardly beyond the outward perimeter 111 of the plate 710 relative to the path of one or more charged particle beams. This allows the outward perimeter 111 of the plate 710 to be located within the outward perimeter 72 of the isolator 750.

[0160] The protrusion 713 may not need to protrude outwardly to the outward periphery of the stack. In an embodiment, the protrusion 713 is an indentation adjacent to the periphery of the isolators 750, 760, such as provided by a cutout portion. For example, a cutout can be provided that conforms to or is located within the shape of the periphery 751 of the shield 61, such as within the periphery of the planar member 70 of the shield. The periphery 751 of the shield 61 can be an inwardly extending portion of the periphery of the shield. Therefore, the protrusion 713 can protrude to the outside of the isolator together with the indentation. By providing an indentation, the protrusion 713 of the plate 710 can be used for electrical connection, such as the protrusion being exposed (not covered) for electrical connection with a flexible coupler.

[0161] In an embodiment, the shield 61 is arranged so that the size of the field-free region 62 in a direction across the beam path (e.g., a direction parallel to the plane of the plate 710) is larger than the size in a direction along the beam path (e.g., a direction perpendicular to the plane of the plate 710). The electrical connector 60 is configured to electrically connect the plate 710 to a power source away from the beam path of the electron beam. The electrical path typically extends from the electron optical device 40 away from the beam path in a radial direction.

[0162] Fig.12 is a schematic diagram of an electrical connector 60 of an exemplary electro-optical assembly 700 . Fig.12 At least some features of the electronic optical assembly 700 and the electrical connector 60 shown are similar to those described above and for example Figure 7The features shown are the same for electrical connection to a power source; for example the assembly comprises an insert component (such as a flexible coupler) and a receiving component (such as a connector 60), which may include a shield 61 or be implemented by a shield 61 (in the present arrangement). The receiving component and the insert component may be engaged with each other, for example removably engaged, for example essentially a plug and socket. It is to be noted that in the arrangement, the connector 60 is essential to ensure the electrical connection; although it is essentially the engagement of a plug and socket (which are different entities) between the connector and the flexible coupler for making the electrical connection. In order to avoid redundant description, the description of these features will not be repeated. Unless stated to the contrary, Fig.12 This feature of the illustrated embodiment should be considered as Figure 7 Shown and referenced Figure 7 Therefore, the arrangement of the connector and the flexible coupling can be applied to the embodiments described later as well as the above embodiments, such as with Figure 7 Descriptive and Figure 7 shown.

[0163] Fig.12 An electrical connector 60 is shown that is suitable for making an electrical connection through a mechanical compliance mechanism. The connection can be a high voltage connection. Fig.12 As shown, the flexible coupling 63 optionally includes a wiring 74. The wiring 74 is made of a conductive material. For example, in an embodiment, the wiring 74 includes bronze, such as phosphor bronze. In an alternative embodiment, the wiring 74 includes, for example, copper. In an embodiment, the wiring 74 is compliant in at least one degree of freedom, optionally at least two degrees of freedom, and optionally five degrees of freedom.

[0164] like Fig.12 As shown, in an embodiment, the flexible coupling 63 includes a resilient element 75. In an embodiment, the resilient element is resilient in degrees of freedom. In particular, the resilient element 75 is resilient in degrees of freedom different from the degrees of freedom to which the wiring 74 complies. In an embodiment, the flexible coupling 63 including the wiring 74 and the resilient element 75 is compliant in all six degrees of freedom.

[0165] In an embodiment, the flexible coupling 63 has an elongated direction, for example, an elongated dimension. In an embodiment, the elastic element 75 is elastic in a degree of freedom corresponding to the elongated direction of the flexible coupling 63. The elongated direction of the flexible coupling 63 may be a direction in which the wiring 74 is less compliant.

[0166] like Fig.12 As shown, in an embodiment, the elastic element is spring loaded, such as a spring loaded element, which can be referred to as a spring pin. The spring pin can be connected to the wiring 74, for example, by welding. In an embodiment, the flexible coupling 63 is configured to be positionable relative to the shield 61 in at least five degrees of freedom.

[0167] In an embodiment, the flexible coupler 63 is connected to the shield 61 at a connection point 68. In such an embodiment, the flexible coupler is secured to the shield and can be connected to the cable 64. For example, in an embodiment, the electrical connector 63 is welded to the shield 61 at the connection point 68. The wire 74 can be welded to the shield 61. The flexible coupler 63 is electrically connected to the cable 64 at a connection point (e.g., at an end 69 of the cable 64). Fig.12 As shown, in an embodiment, the cable 64 includes a landing pad 76 or more generally a connection surface. The landing pad can be located at the end 69 of the cable 64. The connection surface or more specifically the landing pad 76 is configured to accommodate an elastic element 75. The elastic element 75 is directly electrically connected to the landing pad 76 of the cable 64. In an embodiment, the landing pad can be a recessed surface. The recessed surface is recessed toward the center of the surface. The center of the surface may be the deepest recessed. The center of the surface may be referred to as a connection point. When the landing pad and the spring-loaded pin are positioned together, the elasticity of the spring-loaded pin may be sufficient to resist compressing the pin to disengage the pin from the pad, such as at the connection point, so that the pin and the pad remain engaged, and any force in the direction of the pin is absorbed by the elasticity of the pin instead of being applied to the electronic optical component 700.

[0168] In an alternative embodiment not shown in the drawings, the orientation of the flexible coupler 63 is reversed. The wiring 74 can be located between the elastic element 75 and the cable 64. The elastic element 75 can be located between the shield 61 and the wiring 74. In this arrangement, the landing pad 76 can be provided at the surface of the shield 61 to form the connection point 68. In this embodiment, the flexible coupler 63 is secured to the cable 64 and can be connected to the shield 61.

[0169] In an embodiment, the diameter of the shield 61 (which may also be referred to as an HV cover (high voltage cover)) is greater than the diameter of the cable 64. In an embodiment, the shield 61 has an outer surface that is at least partially rounded. This may help reduce the electric field outside the shield 61, thereby preventing discharge.

[0170] In an embodiment, the shield 61 is bonded to the board 710 (or conductive layer). For example, in an embodiment, the shield 61 is soldered to the board 710. Solder provides good electrical contact within a limited volume and is also suitable for vacuum conditions.

[0171] In an embodiment, the flexible coupling 63 can be disconnected and reconnected with at least one of the cable 64 and the shield 61. Fig.12In the illustrated embodiment, the flexible coupler 63 can be easily disconnected from the cable 64. A pogo pin or other type of resilient element 75 can be released from a landing pad 76 at the end 69 of the cable 64. This can make it easier to replace the electron-optical assembly 700 within the electron-optical device 40. In an alternative embodiment where the orientation of the flexible coupler 63 is reversed, the flexible coupler 63 can be easily disconnected from the connection point 68 of the shield 61.

[0172] In an embodiment, a method of disconnecting the electron-optical assembly 700 from the electron-optical device 40 is provided. The method includes electrically disconnecting the board 710 from the power source by disconnecting the flexible coupler 63 from the electron-optical assembly 700 or the power source. When the flexible coupler 63 is disconnected from the power source, the flexible coupler 63 may remain connected to the electron-optical assembly 700. Alternatively, when the flexible coupler 63 is disconnected from the electron-optical assembly 700, the flexible coupler 63 may remain connected to the power source.

[0173] In an embodiment, the method further includes disconnecting the electron-optical assembly 700 from the electron-optical device 40. The electron-optical assembly 700 can be replaced with a replacement electron-optical assembly. The replacement electron-optical assembly can be connected to the power supply and the rest of the electron-optical device 40. For example, the flexible coupler 63 can be reconnected to the power supply or the electron-optical assembly can be replaced.

[0174] Fig.13 is a schematic diagram of an electrical connector 60 of an exemplary electronic optical assembly 700. Possible features of the electronic optical assembly 700 and the electrical connector 60 described elsewhere in this document may be applied to Fig.13 The electro-optical assembly 700 and electrical connector 60 are shown, noting the features and functions that may be used as engageable receiving and inserting components, such as plugs and sockets in nature. Fig.13 The characteristics can be Figures 7 to 12 Shown and referenced Figures 7 to 12 Any of the embodiments described above are the same, providing Fig.13 To illustrate features of the electrical connector 60 , these features may be applied to other embodiments described elsewhere in this document.

[0175] like Fig.13 As shown, in an embodiment, the shield 62 is arranged so that the field-free region 62 is adjacent to the surface of the plate 710 in a plane passing through the beam path. Fig.13As depicted, the shield may be secured to the plate 710 and may be an electrical conductor with a recess defining a field-free region 62 for the flexible coupler 63 (e.g., such that the field-free region is field-free relative to the flexible coupler 63), but specific features may be relevant to other embodiments such as those disclosed herein. In an embodiment, the field-free region 62 at least partially overlaps the plate 710 when viewed in a direction within the plane of the plate 710. Alternatively expressed, the field-free region is at least partially located in the sample plane of the plate 710. Extending the field-free region into the same plane as the plate may help reduce the extent to which the shield 61 extends in a direction along the beam path and / or orthogonal to the plate. This helps to reduce, if not minimize, the distance above and / or below the plate 710. As Fig.13 As shown, in embodiments, shield 61 may extend upward, e.g., no further upward than upstream isolator 750. In embodiments (not shown), shield 61 may extend downward as far as downstream isolator 760. The exact arrangement of shield 61 relative to plate 710 may be selected depending on the spatial constraints of electron-optical assembly 700, such as the volume available for electron-optical assembly 70 in electron-optical device 40.

[0176] like Fig.13 As shown, in an embodiment, the shield 61 (e.g., an electrical conductor) includes an inwardly protruding edge portion 77 or a protruding shelf portion. The shape of the protruding edge portion 77 has a surface corresponding to the planar surface of the protrusion and the side surface of the protrusion. The protruding edge portion 77 is configured to provide a mechanical and / or electrical connection between the shield 61 and the plate 710 and optionally between the protruding isolator portion of the protrusion 713. Fig.13 As shown, shield 61 and plate 710 can be connected to each other via connection surface 67, such as a planar portion of the connection surface. Connection surface 67 (such as a side of connection surface 67) can also connect shield 61 to side surface protrusions, such as plate 710 and / or spacer 760. By providing connection surface 67, the mechanical and / or electrical connection between plate 710 and shield 61 can become robust, reliable and stable. Figure 7 and Fig.12 Such a connection surface 67 between a shielding element 61 (eg as a connecting body or an electrical conductor) and a planar portion of the connection surface 67 is also shown in FIG.

[0177] like Fig.13As shown, in an embodiment, the shield 61 includes an indentation, such as a cutout portion. The cutout portion can be defined below the protruding edge portion 77. The indentation can be shaped to correspond to a portion of the inner periphery of the shield, desirably the protruding edge portion. The indentation can be shaped to accommodate at least a portion of the inner periphery of the protruding edge portion of the shield. At least a portion of the plane of the connecting surface 67 (desirably the inward portion) can be shaped to correspond to the indentation. The cutout shape allows mechanical and / or electrical connection to the board 710.

[0178] like Figure 6 and Fig.14 As shown, in an embodiment, the electron optical assembly 700 includes a second electron optical element, which includes a plate 720. The electron optical assembly 700 may have Figures 7 to 13 Description and references Figures 7 to 13 The same features and similar functions as described. Plate 720 has one or more apertures around the beam path of the electron beam. Fig.14 An arrangement of an electron-optical assembly 700 is shown which also includes a third electron-optical element comprising a plate 730. Fig.14 Three plates 710, 720, 730 are shown, but in embodiments, the electronic optical assembly 700 may include more than three plates. Each plate may be individually connected to a power supply. One or more plates may be connected to a high voltage power supply so that the potential difference between the plate surfaces can be controlled to control the electric field adjacent to the plate. Each plate may be provided with its own electrical connector 60. In an arrangement, a plurality of plates have a common electrical connector 60 and therefore a common electrical connection.

[0179] Fig.15 yes Fig.14 Schematic diagram of a side view of the arrangement shown. Fig.15 Three shields 61 of three electrical connectors of three plates 710, 720, 730 are shown, which can be referred to as upstream plate 710, middle plate 720, and downstream plate 730. The shields can be referred to as leftmost shield 612, middle shield 613, and rightmost shield 614. Each shield 612-614 defines a field-free region 62, for example, relative to the insertion of an object such as a flexible coupler 63. In the electrical conductors of the respective shields 612-614, grooves define the field-free region 62.

[0180] like Fig.15 As shown, in an embodiment, each shield 612 to 614 (eg, electrical conductors) is mounted on a corresponding plate 710 , 720 , 730 . Fig.14 and Fig.15The illustrated electron-optical assembly 700 includes other isolators 770, 780 adjacent to other plates 720, 730, such that each plate 710, 720, 730 has two adjacent isolators, in the upstream and downstream directions of the individual plates. The isolators may serve as upstream isolators and downstream isolators of the respective adjacent plates along the beam path. For example, the upstream plate 710 has adjacent isolators 750, 760; the intermediate plate 720 has adjacent isolators 760, 770; and the downstream plate 730 has adjacent isolators 770, 780. Fig.15 In the arrangement shown, the leftmost shield 612 is connected to the upstream board 710 for connecting the upstream board 710 to a power source. Fig.15 An intermediate shield 613 is shown for connecting the downstream plate 730 to a power source. Fig.15 The rightmost shield 614 is shown for electrically connecting the midplane 720 to a power source. In an embodiment, the shields 612 to 614 are electrically isolated from each other. Alternatively, the shields 612 to 614 may be electrically connected to each other.

[0181] like Fig.15 As shown, the electrical connector 60 is optionally arranged such that the shields 612 to 614 define respective field-free regions 62 (e.g., relative to a pluggable power supply such as a flexible coupling) that overlap each other in a direction along the beam path. Fig.15 When the electrical connector 60 is viewed in the view shown, i.e., in a direction parallel to the plane of the plates 710, 720, 730, the field-free regions 62 overlap each other, desirably in substantially the same plane, for example at the same position along the beam path direction. This may help to simplify the connection of the plates 710, 720, 730 to different potentials.

[0182] In different arrangements of the electronic optical assembly 700, the plate 710 and the isolators 750, 760 do not extend further outward than the periphery of the stack. In this arrangement, the connection surface 67 has only a side portion, for example, it does not have a planar portion. The side portion includes at least a side surface of the plate 710 (or a conductive layer in the plate plane) and at least one adjacent isolator, which can be in the upstream and / or downstream direction of the plate 710. The stack itself has no protrusions, although the plate or alternatively the conductive layer electrically connected to the plate 710 can extend to the peripheral surface of the stack at the side portion to replace the dielectric, which may be present in other places in the plane of the plate 710 at the periphery of the stack. The shield 61 has a surface shaped to correspond to the side portion of the connection surface. This arrangement avoids the need for protrusions and is directly connected to the plate or the conductive layer in the plate plane, and is mechanically stabilized to the stack via the peripheral surface of at least one isolator. The plate and / or the conductive layer can extend partially along the peripheral surface of the adjacent isolator to increase the electrical contact between the plate 710 and the shield 61. To ensure a secure connection, the shield can be mechanically connected to the other boards (or conductive layers) via a dielectric layer to ensure that the shield 61 is electrically isolated from each other board. However, while useful, this arrangement of the electrical connector 60 can have a less secure mechanical connection of the shield to the electronic optical component than an electrical connector having protrusions 713.

[0183] In an embodiment, the electron-optical assembly 700 includes one or more electron-optical elements, which include elements that can be referred to as micro-electromechanical components (although such components may not include moving or movable features), or can be manufactured using a technology suitable for manufacturing micro-electromechanical components (e.g., 'MEMS technology'), some of which are designed to have electron-optical functionality. The electron-optical assembly 700, or at least components of the electron-optical assembly 800, can be manufactured using such technology. The electron-optical assembly 700 may include one or more elements that can be considered as MEMS elements. During use, one or more of such elements may be controlled to be set to a high potential difference relative to a reference potential (e.g., ground). Such elements may need to be accurately positioned (e.g., aligned) within the electron-optical assembly 700, such as relative to the path of the beam grid and relative to other electron-optical elements within the device, such as relative to the source, relative to the path of the sample and / or the beam grid. Embodiments of the present invention are expected to allow such elements to be more accurately positioned (e.g., aligned) within a stack of such electron-optical assemblies 700, so that during operation, for example, the electron-optical assembly 700 is not distorted by, for example, externally applied forces or torques. Embodiments of the present invention may additionally or alternatively enable more accurate positioning, e.g., alignment, of such elements relative to other elements in device 40 , thereby enabling more accurate positioning, e.g., alignment, of a stack of electro-optical assemblies 700 including such elements within device 40 .

[0184] As mentioned above, in an embodiment, the electron optical assembly 700 is an electron optical lens assembly. The electron optical lens assembly may include an objective lens assembly. The electron optical lens assembly may be an objective lens assembly. In an alternative embodiment, the electron optical lens assembly is an electron optical converging lens assembly.

[0185] In an embodiment, the electron optical assembly 700 includes a collimator. For example, in an embodiment, the electron optical assembly 700 includes a magnetic collimator combined with an electrostatic focusing lens array. The electron optical assembly 700 may include a single aperture lens array with one or two macro electrodes placed away from the virtual source conjugate plane.

[0186] In an alternative embodiment, the electron optical assembly 700 includes a magnetic macro lens combined with an electrostatic slit deflector. The magnetic macro lens can be used for collimation. As a further alternative, in an embodiment, the electron optical assembly 700 includes a combined magnetic and electrostatic macro lens and a downstream slit deflector.

[0187] Generally, the electron-optical assembly 700 may include any plates, such as plates of detector arrays, plates of lens electrodes (in which multiple deflectors may be integrated), multiple deflector arrays, beam aperture arrays (e.g., upper beam aperture arrays and / or final beam limiting arrays), deflector arrays (e.g., strip deflector arrays), and other types of corrector elements.

[0188] The embodiments described within this document focus primarily on a multi-beam electron optical device 40. The present invention is equally applicable to a single-beam electron optical device 40.

[0189] In an embodiment, multiple electrical connectors 60 may be provided for the same board. For example, the board 710 may include different electrodes to which different potentials are applied during use of the electron-optical assembly 700. For example, in an embodiment, the board 710 is a strip electrode, wherein each electrode in the strip electrode has or can have a different potential applied. In different embodiments, alternating electrodes may have a common applied potential so that adjacent electrodes have different applied potentials. Each board 710 may have more than one electrical connector 60. Similarly, a deflector having multipolar electrodes may need to apply different potentials to the board for different electrodes; for example, the board may include multiple deflectors, common electrodes for different deflectors having a common electrical connector 60.

[0190] like Figure 7 and Figure 12 to Figure 14As shown, in an embodiment, the flexible coupler 63 is connected to the shield 61 at a connection point 68 and to the cable 64 at another connection point, such as at an end 69 of the cable 64. That is, these connection arrangements of the shield 61 of the connector 60 and the cable, such as the flexible coupler, are described as examples of engageable (e.g., removably connectable) male and female components, such as essentially a plug and a socket. Fig.16 is a schematic diagram showing an example of how a flexible coupler 63 may be connected to a shield 61 and a cable 64 (e.g., how to connect an insert component of a cable 64 to a receiving component of a shield 61 using, for example, a flexible coupler, which may be part of the insert component or the receiving component). Fig.16 The features of the electrical connector 60 shown and described may be applied to any other embodiments disclosed herein, such as Figure 7 and Figure 12 to Figure 14 Shown and referenced Figure 7 and Figure 12 to Figure 14 Described. In an embodiment, the flexible coupler 63 is connected to the shield 61 by a clamp (e.g., a bracket clamp). In an embodiment, the shield 61 forms a clamp, for example, including two parts, i.e., an upper part and a lower part. The shield 61 includes an upper bracket and a lower bracket (i.e., an upper part and a lower part, respectively). The upper bracket and the lower bracket can be initially formed as separate parts and then combined together to form the shield 61, such as the conductive body of the shield. Fig.16 The joint 79 between the two parts of the shield 61 is shown. Fig.16 As shown, in an embodiment, a fastener, such as a fastener member 78, is provided to secure the two brackets of the shield 61 together.

[0191] In an embodiment, one end of the flexible coupler 63 is located between two brackets of the shield 61. The flexible coupler 63 can be located between two parts of the shield 61, such as sandwiched therebetween. The end of the flexible coupler 63 is located in a joint 79 of the shield 61. The flexible coupler 63 can be positioned on the lower bracket, and the upper bracket is then placed on top of the lower bracket and the flexible coupler 63. Then, a fixing member 78 is applied to secure the flexible coupler 63 in place relative to the shield 61. In an embodiment, the fixing member includes, for example, a pin, a nail, or a screw.

[0192] like Fig.16 As shown, in an embodiment, the other end of the flexible coupler 63 can be connected to the conductor 66 of the cable 64. In an embodiment, the flexible coupler 63 is crimped onto the conductor 66. Alternatively, the flexible coupler 63 can be welded, adhered or friction-fitted to the conductor 66 of the cable 64.

[0193] Fig.17Schematic diagram of an alternative way to connect a flexible coupling 63 to a shield 61 or to connect a cable 64 to a shield 61 via a flexible coupling 63, the flexible coupling 63 may be part of the cable 64, or may be an insert component that may include the cable 64 and the flexible coupling. Fig.17 As shown, in an embodiment, the flexible coupler 63 is connected to the shield 61 by a fixture (such as a compression fixture), for example, by a set screw 80. In an embodiment, the shield 61 includes a groove for accommodating the set screw 80. In an embodiment, the shield 61 includes another groove for accommodating the end of the flexible coupler 63. The set screw 80 is inserted to nail (or compress and secure) the end of the flexible coupler 63 in the groove of the shield 61.

[0194] Fig.18 61 or a cable 64 connected to the shield 61 via the flexible coupling 63, the flexible coupling 63 may be part of the cable 64, or may be an insert component that may include the cable 64 and the flexible coupling. In different arrangements, the flexible coupling may be part of the connector, or may include a portion that is part of the shield 61 (and the connector 60) and an insert component that also includes the cable 64. As shown in FIG. Fig.18 As shown, in an embodiment, a securing connector (or retainer) 81 is provided to connect the flexible coupler 63 to the shield 61. In an embodiment, the securing connector 81 is configured to be inserted (e.g., compression secured) into the shield, such as being pushed or screwed into the shield 61, so as to form an electrical connection between the shield 61 and the flexible coupler 63. The flexible coupler 63 may be attached to the end of the connector 81 that is not inserted (e.g., pushed into) the shield 61. In an embodiment, the shield 61 is provided with a groove for accommodating the connector 81 to be pushed therein.

[0195] In alternative embodiments, the orientation of the flexible coupler 63 and the connector 81 can be reversed. In particular, in an embodiment, the connector 81 is located between the flexible coupler 63 and the conductor 66 of the cable 64. For example, the connector 81 can be fixed relative to the conductor 66, for example by using a conductive bonding material, such as a conductive adhesive or a weld. One end of the flexible coupler 63 is connected to the connector 81. The other end of the flexible coupler 63 can be directly connected to the shield 61.

[0196] In an alternative embodiment, the flexible coupling 63 is connected to the shield 61 via a landing pad, similar to Fig.12The landing pad 76 shown. Possible features of the landing pad are described elsewhere in this document. The landing pad may be provided at the end surface of the groove forming the field-free region 62. The flexible coupler 63 may be a fixture and may be pushed against the landing pad by an elastic member (such as a spring). The other end of the flexible coupler 63 may be connected to the conductor 66 of the cable 64 as described above. In yet another alternative embodiment, the landing pad may be located at the end of the cable 64. An elastic member such as a spring may be provided to generate a small thrust to keep the flexible coupler 63 in contact with the landing pad at the end of the cable 64. The other end of the flexible coupler 63 may be directly connected to the shield 61.

[0197] In an alternative embodiment, the flexible coupler 63 may be connected to the shield 61 by a retainer such as a push clip. The shield 61 may include a groove into which one end of the flexible coupler 63 extends. The push clip may be provided by another groove in the clamp 61 for holding the end of the flexible coupler 63 relative to the shield 61. In an embodiment, the end of the flexible coupler 63 may extend through the push clip to prevent the push clip from pushing itself out of the shield 61. The push clip ensures that contact is maintained between the flexible coupler 63 and the shield 61.

[0198] exist Figures 16 to 18 Shown and referenced Figures 16 to 18 Describe and more generally refer to at least Figure 7 and Figure 12 to Figure 14 In the different arrangements described, there may be an insertion component and a receiving component that are mutually engageable (such as removably). The connector 60 may be used as a receiving component and may include a shield 61. A flexible coupler 63 may be used as an insertion component or a portion of an insertion component. The insertion component may include a cable 64 or at least an end of a cable. The receiving component may accommodate the insertion component to achieve electrical connection. The insertion component may be inserted into the receiving component, such as in a groove defined in the receiving component, which defines a field-free area to achieve electrical connection.

[0199] The detector may form part of an electro-optical device such as Figures 1 to 5 The electron optical device 40 of any one of the above. The electron optical device can be configured to generate a beam wave from a source beam and project the beam wave toward the sample. The detector can be arranged facing the sample and configured to detect electrons emitted from the sample. The detector can include a current detector array. Signal communication with the detector array can include signal communication via optical fiber, which can be included in the objective lens assembly. The electron optical device can include the electron optical device. The electron optical device can include a source configured to emit an electron beam. Alternatively, the source can be part of the electron optical device rather than part of the electron optical device. The electron optical device can include one or more electron optical components.

[0200] A plurality of electron-optical devices may be comprised in an electron-optical device array.The electron-optical devices in the electron-optical device array are preferably configured to focus respective multiple beams simultaneously onto different areas of the same sample.

[0201] Although the present invention has been described in conjunction with various embodiments, other embodiments of the present invention will be apparent to those skilled in the art in view of the description and practice of the present invention disclosed herein. For example, as described above, in an embodiment, the electronic optical assembly 700 includes an electrical connector 60. However, the electrical connector 60 of the present invention can be used anywhere in the electronic optical device 40 where there may be a possible electrical breakdown problem. In an embodiment, the electronic optical device 40 includes an electrical connector 60 separated from the electronic optical assembly 700. For example, the electrical connector 60 can be located at a position where a low-force electrical connection is required to other parts of the electronic optical device 40 (such as the body or frame of the electronic optical device 40). The electrical connector 60 can be located at a position where a particularly low-force electrical connection is not required. The electrical connector 60 can make the electronic optical device 40 more compact while providing a field-free region, for example, relative to a coupler, and the field-free region is field-free relative to the coupler. The description and examples are intended to be considered as exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0202] The above description is intended to be illustrative, rather than limiting. Therefore, it will be apparent to those skilled in the art that modifications can be made as described without departing from the scope of the claims and clauses set forth below.

[0203] The following terms are provided:

[0204] Item 1. A charged particle optical device for projecting multiple charged particle beams along corresponding beam paths toward a sample position, the charged particle optical device comprising: a charged particle optical component configured to manipulate the charged particle beam, the charged particle optical component comprising a first charged particle optical element, the first charged particle optical element comprising a plate having one or more apertures surrounding the beam path of the charged particle beam; and an electrical connector configured to electrically connect the plate of the charged particle optical element to a power source, wherein the electrical connector: comprises a shield configured to define a field-free region substantially free of an electric field; and is configured to be electrically connectable via a flexible coupler, the flexible coupler being configured to electrically connect the plate of the charged particle optical element to the power source, the flexible coupler being located within the field-free region.

[0205] Clause 2. The charged particle optical device of clause 1, wherein at least part of the shield overlaps the plate of the charged particle optical element when viewed in a direction perpendicular to the plane of the plate of the charged particle optical element.

[0206] Clause 3. Charged particle optical device according to clause 2, wherein the portion of the shield overlapping the plate of the charged particle optical element is located only at one of the upstream side and the downstream side of the plate.

[0207] Clause 4. A charged particle optical device according to any preceding clause, wherein the plate of the charged particle optical element is configured to be electrically connectable to the flexible coupling via a shield.

[0208] Clause 5. Charged particle optical device according to any preceding clause, wherein the shield is mechanically fixed relative to a plate of the charged particle optical element by a mechanical connection.

[0209] Clause 6. Charged particle optical device according to clause 5, wherein the shield and the plate are electrically connected via a mechanical connection.

[0210] Clause 7. Charged particle optical device according to any preceding clause, wherein the charged particle optical component comprises at least one isolator adjacent to the plate.

[0211] Clause 8. A charged particle optical device according to clause 7, wherein the isolator is substantially planar.

[0212] Clause 9. A charged particle optical device according to clause 7 or 8, wherein the spacer is substantially parallel to the plate.

[0213] Clause 10. Charged particle optical apparatus according to any of clauses 7 to 9, wherein the plate comprises a protrusion which projects beyond a radially outward periphery of the isolator relative to the beam path.

[0214] Clause 11. A charged particle optical apparatus according to clause 10, wherein at least a radially inward portion within an outward periphery of the isolator relative to the beam path is electrically connectable to the flexible coupling via the protrusion.

[0215] Clause 12. A charged particle optical device according to any preceding clause, wherein the flexible coupling comprises a wire extending in an elongated direction.

[0216] Clause 13. A charged particle optical device according to any preceding clause, wherein the flexible coupling comprises an elastic element.

[0217] Clause 14. A charged-particle optical device according to clause 13, wherein the elastic element is elastic in the degree of freedom.

[0218] Clause 15. A charged particle optical device according to clause 14, wherein the flexible coupling has an elongation direction, and the elastic element is elastic in a degree of freedom corresponding to the elongation direction of the flexible coupling.

[0219] Clause 16. Charged-particle optical apparatus according to any one of clauses 13 to 15, wherein the elastic element is a pogo pin.

[0220] Clause 17. A charged particle device according to any preceding clause, wherein the flexible coupling is configured to be positionable in at least five degrees of freedom relative to the shield.

[0221] Clause 18. A charged particle optical device according to any preceding clause alone, wherein the shield is arranged to surround the flexible coupling when viewed in at least one direction.

[0222] Clause 19. The charged particle optical device of Clause 18, wherein the shield defines a recess configured to receive the flexible coupler.

[0223] Clause 20. The charged particle optical device of Clause 19, wherein the groove has a substantially circular cross-section.

[0224] Clause 21. A charged-particle optical device according to Clause 20, wherein the substantially circular cross-section is orthogonal to the depth of the groove.

[0225] Clause 22. A charged particle optical device according to any one of clauses 19 to 21, wherein the groove is configured to have a surface that is concentric with the elongation direction of the flexible coupling.

[0226] Clause 23. A charged particle optical device according to any preceding clause, wherein the shield comprises an electrical conductor, desirably with a groove defined therein, desirably the body being configured to be electrically connected via the flexible coupling.

[0227] Clause 24. A charged particle optical device according to any one of clauses 1 to 17, wherein the shield comprises two planar members defining a field-free region between the two planar members, wherein the shield is desirably isolated from the flexible coupler, desirably the flexible coupler is connected to a power source different from that of the flexible coupler.

[0228] Clause 25. A charged particle optical device according to any preceding clause, wherein the shield is arranged such that the field-free region has a larger dimension in a direction parallel to the plane of the plate than in a direction perpendicular to the plane of the plate.

[0229] Clause 26. Charged particle optical apparatus according to any preceding clause, wherein the shield is arranged such that the field-free region is adjacent to a surface of a plate in the plane across the beam path.

[0230] Clause 27. A charged particle optical device according to any preceding clause, wherein the electrical connector comprises a cable configured to electrically connect the flexible coupler to the power source, wherein the flexible coupler is more flexible than the cable in at least one degree of freedom.

[0231] Clause 28. A charged particle optical device according to any preceding clause, wherein the plate has an array of apertures.

[0232] Clause 29. A charged particle optical device according to Clause 28, wherein the apertures of the array are used for the beam paths of corresponding charged particle beams.

[0233] Clause 30. A charged particle optical device according to any preceding clause, the charged particle plate being a first charged particle plate, wherein the charged particle optical component comprises a second charged particle optical element comprising a plate having one or more apertures surrounding a beam path of the charged particle beam.

[0234] Clause 31. The charged particle optical device of clause 30, comprising a further electrical connector configured to electrically connect the board of the second charged particle optical element to the power supply.

[0235] Clause 32. Charged-particle optical apparatus according to Clause 31, wherein the electrical connectors are arranged such that the shields define respective field-free regions which overlap each other in a direction along the beam path.

[0236] Clause 33. A charged-particle optical device according to any preceding clause, wherein the electrical connector comprises the flexible coupling.

[0237] Clause 34. A charged-particle optical device according to any preceding clause, wherein the electrical connector comprises a holder configured to connect to the flexible coupling.

[0238] Clause 35. A charged particle optical device according to any preceding clause, wherein the charged particle optical assembly comprises one or more charged particle optical elements, the one or more charged particle optical elements comprising micro-electromechanical components.

[0239] Clause 36. A charged particle optical device according to any preceding clause, wherein the charged particle optical component is a charged particle optical lens component.

[0240] Clause 37. The charged particle optical device of Clause 36, wherein the charged particle optical lens assembly comprises an objective lens assembly.

[0241] Clause 38. The charged particle optical device of Clause 36, wherein the charged particle optical lens assembly is an objective lens assembly.

[0242] Clause 39. The charged particle optical device of any one of Clause 36, wherein the charged particle optical lens assembly comprises a charged particle optical converging lens assembly.

[0243] Clause 40. A charged particle optical device according to any preceding clause, wherein the charged particle optical component comprises a collimator.

[0244] Item 41. A charged particle optical component for manipulating one or more charged particle beams in a charged particle device along a beam path toward a sample position, the charged particle optical component comprising: a charged particle optical element comprising a plate having one or more apertures surrounding a beam path of one or more charged particle beams and configured to manipulate the one or more charged particle beams; and at least one isolator adjacent to the plate around the beam path and configured to mechanically support the plate and electrically isolate the plate; and an electrical connector configured to electrically connect the plate to a power source, wherein the electrical connector comprises a protrusion of the plate extending radially outwardly of an outer periphery of the isolator or one of the isolators relative to the beam path, the protrusion being configured to be connectable to the power source via a flexible coupler in a field-free region where there is substantially no electric field.

[0245] Clause 42. The charged-particle optical component of Clause 41, wherein the electrical connector comprises a shield configured to define the field-free region.

[0246] Clause 43. A charged particle optical component according to clause 41 or 42, wherein the electrical connector comprises a fixture configured to connect to the flexible coupler to electrically connect the board to the power source.

[0247] Clause 44. The charged-particle optical component of Clause 43, wherein the connector is located in the field-free region during operation of a charged-particle device including the charged-particle optical component.

[0248] Clause 45. A charged particle optical component according to clause 41 or 42, wherein the electrical connector comprises the flexible coupler located within the field-free region.

[0249] Item 46. A charged particle optical component configured to direct multiple charged particle beams in a beam grid toward a sample, the component comprising a charged particle optical component comprising: a planar charged particle optical element configured to operate at a high voltage on a charged particle beam of the beam grid, the element comprising multiple apertures for the paths of different beams of the beam grid; and an isolation spacer configured to: support and electrically isolate the charged particle optical element and be positioned away from the beam path; and an electrical conductor structurally connected to a connection surface of the component and electrically connected to the charged particle element, wherein a groove is defined within the electrical conductor and is configured to provide a field-free volume for inserting an electrical coupler to electrically connect the charged particle optical element to the electrical conductor via the electrical coupler.

[0250] Clause 47. The charged particle optical component of Clause 46, wherein the connection surface comprises a surface of the isolation spacer.

[0251] Clause 48. The charged particle optical component of Clause 46, wherein the connection surface comprises a surface of the charged particle optical element.

[0252] Clause 49. A charged particle optical component according to Clause 46, wherein the connection surface is a protruding portion desirably comprising a portion of the spacer.

[0253] Clause 50. A charged particle optical component according to any one of Clauses 46 to 49, wherein a portion of the connection surface extends outwardly from a periphery of the component relative to the path of the beam grid.

[0254] Item 51. A charged particle optical apparatus, comprising: a charged particle optical device according to any one of items 1 to 40 or a charged particle optical component according to any one of items 41 to 50; and an actuatable platform configured to support a sample.

[0255] Item 52. A method for providing an electrical connection, the method comprising: providing a charged particle optical device, the charged particle optical device being configured to project a plurality of charged particle beams along corresponding beam paths toward a sample position, the charged particle optical device comprising a charged particle optical component configured to manipulate the charged particle beams, the charged particle optical component comprising a charged particle optical element, the charged particle optical element comprising a plate having one or more apertures surrounding the beam path of the charged particle beam; and providing an electrical connector, the electrical connector being configured to electrically connect the plate to a power source, wherein the electrical connector: comprises a shield configured to define a field-free region having substantially no electric field; and is configured to be capable of being electrically connected to a flexible coupler, the flexible coupler being configured to electrically connect the plate to the power source, the flexible coupler being located within the field-free region.

[0256] Clause 53. The method of clause 52, comprising disconnecting the flexible coupling from the power source, wherein the flexible coupling remains connected to the charged-particle optical lens assembly.

[0257] Clause 54. The method of clause 53, comprising replacing the flexible coupler and the charged-particle optical lens assembly with a replacement flexible coupler and a replacement charged-particle optical lens assembly.

[0258] Clause 55. The method of clause 54, comprising connecting the replacement flexible coupler to the power source such that the replacement charged-particle optical lens assembly is electrically connected to the power source via the replacement flexible coupler.

[0259] Clause 56. The method of any one of clauses 52 to 55, comprising disconnecting the charged-particle optical component from the charged-particle optical device.

[0260] Clause 57. The method of Clause 56, comprising replacing the charged particle optical lens assembly with the replacement charged particle optical assembly.

[0261] Item 58. A method for disconnecting a charged particle optical component from a charged particle optical device, the charged particle optical device being configured to project multiple charged particle beams along corresponding beam paths toward a sample position, the charged particle optical device comprising a charged particle optical component configured to manipulate the charged particle beams, the charged particle optical component comprising a charged particle optical element, the charged particle optical element comprising a plate having one or more apertures surrounding the beam path of the charged particle beam, the plate being electrically connected to a power supply via a flexible coupler located within a field-free region defined by a shield, the method comprising: electrically disconnecting the plate from the power supply by disconnecting the flexible coupler from one of the power supply and the charged particle optical component, wherein the flexible coupler remains connected to the other of the charged particle optical component and the power supply.

[0262] Clause 59. The method of Clause 58, comprising disconnecting the charged-particle optical component from the charged-particle optical device.

[0263] Clause 60. The method of Clause 59, comprising replacing the charged particle optical component with a replacement charged particle optical component.

Claims

1. A charged particle optical device for projecting a plurality of charged particle beams along respective beam paths toward a sample location, the charged particle optical device comprising: a charged particle optical assembly configured to manipulate the charged particle beam, the charged particle optical assembly comprising a first charged particle optical element comprising a plate having one or more apertures surrounding a beam path of the charged particle beam; and an electrical connector configured to electrically connect the board of the charged-particle optical element to a power source, wherein the electrical connector: including a shield configured to define a field-free region substantially free of an electric field; and The device is configured to be electrically connectable via a flexible coupling, the flexible coupling being configured to electrically connect the plate of the charged-particle optical element to the power source, the flexible coupling being located within the field-free region. 2 . The charged particle optical device according to claim 1 , wherein at least part of the shield overlaps the plate of the charged particle optical element when viewed in a direction perpendicular to the plane of the plate of the charged particle optical element. 3 . The charged particle optical apparatus according to claim 2 , wherein the portion of the shield overlapping the plate of the charged particle optical element is located only at one of an upstream side and a downstream side of the plate.

4. A charged particle optical device according to any preceding claim, wherein the plate of the charged particle optical element is configured to be electrically connectable to the flexible coupling via the shield.

5. A charged particle optical device according to any preceding claim, wherein the shield is mechanically fixed relative to the plate of the charged particle optical element by a mechanical connection.

6. Charged particle optical device according to claim 5, wherein the shield and the plate are electrically connected via the mechanical connection.

7. A charged particle optical device according to any preceding claim, wherein the charged particle optical component comprises at least one isolator adjacent to the plate.

8. A charged particle optical device according to claim 7, wherein the isolator is substantially planar.

9. Charged particle optical apparatus according to claim 7 or 8, wherein the isolator is substantially parallel to the plate.

10. Charged particle optical apparatus according to any one of claims 7 to 9, wherein the plate comprises a protrusion which projects beyond a radially outward periphery of the isolator relative to the beam path.

11. Charged particle optical apparatus according to any preceding claim, wherein the flexible coupling comprises an elastic element that is elastic in a degree of freedom. 12 . The charged particle optical device according to claim 11 , wherein the flexible coupling has an elongated direction, and the elastic element is elastic in a degree of freedom corresponding to the elongated direction of the flexible coupling.

13. A charged particle device according to any preceding claim, wherein the flexible coupling is configured to be positionable in at least five degrees of freedom relative to the shield.

14. A charged particle optical apparatus according to any preceding claim, wherein the shield is arranged to surround the flexible coupling when viewed in at least one direction.

15. The charged particle optical device of claim 14, wherein the shield defines a recess configured to receive the flexible coupling.

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