Electron-optical assembly and module for electron-optical column

Abstract

This document discloses an electro-optic assembly for an electro-optic column used to project a charged particle beam along a beam path toward a target. The electro-optic assembly includes: an electromagnetic shield surrounding the charged particle beam path and configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield includes a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam, wherein the segments are separable.

Description

Technical Field

[0001] The embodiments provided herein are generally related to providing, for example, an electro-optic component, a module, and an electro-optic column for use in a charged particle beam detection apparatus. Embodiments also provide a method for manufacturing the electro-optic component, a method for replacing a module, and a method for projecting a charged particle beam along a beam path toward a target. Prior Technology

[0002] When manufacturing semiconductor integrated circuit (IC) wafers, unwanted pattern defects, such as those caused by optical effects and accompanying particles, inevitably appear on the substrate (i.e., wafer) or mask during the manufacturing process, thereby reducing yield. Therefore, monitoring the extent of unwanted pattern defects is a crucial process in IC wafer manufacturing. More generally, the inspection and / or measurement of the surface of substrates or other objects / materials are important processes during and / or after their manufacturing.

[0003] Pattern inspection tools utilizing charged particle beams have been used to inspect objects, such as to detect pattern defects. These tools typically employ electron microscopy techniques, such as scanning electron microscopy (SEM). In SEM, a final deceleration step is used to target a primary electron beam of electrons at relatively high energies so that it lands on the target at a relatively low landing energy. The electron beam is focused as a probe spot on the target. 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. Secondary electrons can be emitted from the target's material structure. By scanning the target surface with the primary electron beam as a probe spot, secondary electrons can be emitted across the target's surface. By collecting these emitted secondary electrons from the target surface, the pattern inspection tool can obtain an image representing the characteristics of the material structure of the target's surface.

[0004] Another application of electro-optic beams is lithography. A beam of charged particles reacts with a resist layer on the surface of a substrate. The desired pattern in the resist can be created by controlling the position of the charged particle beam as it travels along the guided resist layer.

[0005] An electro-optic beam can be a device used to generate, illuminate, project, and / or detect one or more beams of charged particles. The path of the charged particle beam is controlled by an electromagnetic field. Stray electromagnetic fields can inappropriately deflect the beam.

[0006] Generally, improvements are needed to control the path of charged particle beams. Summary of the Invention

[0007] According to a first aspect of the present invention, an electro-optic assembly for an electro-optic column is provided, the electro-optic column being used to project a charged particle beam along a beam path toward a target, the electro-optic assembly comprising: an electromagnetic shield surrounding the charged particle beam path and configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield comprises a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0008] According to a second aspect of the present invention, a module is provided, comprising an electro-optic device and an electromagnetic shielding member passing through a beam path of the module when in an electro-optic column, the electro-optic column being used to project a charged particle beam along the beam path toward a target, the electromagnetic shielding member comprising an anti-current direction segment in the anti-current direction of the electro-optic device and a co-current direction segment in the co-current direction of the electro-optic device, at least one of the anti-current direction segment and the co-current direction segment having an interface extending radially in a direction of the beam path.

[0009] According to a third aspect of the present invention, an electro-optic assembly for an electro-optic column is provided, the electro-optic column being used to project a charged particle beam along a beam path toward a target, the electro-optic assembly comprising: an electromagnetic shield surrounding the charged particle beam path and configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield comprises a plurality of segments extending along and surrounding the beam path, each segment surrounding the charged particle beam path, wherein at least two of the segments are separable and include adjacent ends that are electromagnetically engaged with each other.

[0010] According to a fourth aspect of the present invention, a method is provided for manufacturing an electro-optic component for an electro-optic column used to project a charged particle beam along a beam path toward a target. The method includes: providing an electromagnetic shield to surround the charged particle beam and shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield includes a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0011] According to a fifth aspect of the present invention, a method is provided for replacing a module of an electro-optic column used to project a charged particle beam along a beam path toward a target. The method includes: removing the module from the electro-optic column, wherein the electro-optic column includes an electromagnetic shield surrounding the charged particle beam path and configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield includes a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein at least one of the segments is included in the module and separable from other segments of the module in the opposite and / or forward directions.

[0012] According to a sixth aspect of the present invention, a method for projecting a charged particle beam along a beam path toward a target is provided, the method comprising: shielding the charged particle beam from an electromagnetic field outside an electromagnetic shield; wherein the electromagnetic shield comprises a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0013] According to a seventh aspect of the present invention, a method of operating an electro-optic component is provided, the electro-optic component being configured to project a charged particle beam along a beam path toward a target, the component comprising: a plurality of electromagnetic shielding sections configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shielding; and a module comprising an electro-optic device and configured to be removable from the component, the method comprising: removing the module from the component, wherein the removal comprises radially moving a section of the electromagnetic shielding within the module relative to the beam path.

[0014] According to an eighth embodiment of the present invention, a multi-column device is provided, comprising: an electro-optic column configured to project individual charged particle beams along respective beam paths toward a target; a charged particle source configured to generate the charged particle beams for one or more of the electro-optic columns; and an electromagnetic shield surrounding the charged particle beam path of at least one of the electro-optic columns; wherein the electromagnetic shield comprises a plurality of segments extending along different positions along the respective beam paths, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0015] The 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 illustrated by way of description and examples. Simple Explanation of the Diagram

[0016] The above and other aspects of the present invention will become more apparent from the description of the exemplary embodiments obtained in conjunction with the accompanying drawings.

[0017] Figure 1 is a schematic diagram illustrating an exemplary charged particle beam detection device.

[0018] Figure 2 is a schematic diagram illustrating an exemplary multi-beam electro-optic column, which is part of the exemplary detection device in Figure 1.

[0019] Figure 3 is a schematic diagram of an electro-optic component according to one embodiment.

[0020] Figure 4 is a schematic diagram of an electro-optical assembly according to one embodiment.

[0021] Figure 5 is a schematic diagram of an electro-optical assembly according to one embodiment.

[0022] Figure 6 is a schematic diagram of a portion of an electro-optic component according to one embodiment.

[0023] Figure 7 is a schematic diagram of an electro-optical assembly according to one embodiment.

[0024] Figure 8 is a schematic diagram of an electro-optical assembly according to one embodiment.

[0025] Figure 9 is a schematic diagram of an electro-optical assembly according to one embodiment.

[0026] Figure 10 is a schematic diagram of an electro-optical assembly according to one embodiment.

[0027] Figure 11 is a schematic diagram of an electro-optic component according to one embodiment.

[0028] Figure 12 is a schematic diagram of an electro-optic column according to one embodiment.

[0029] Figure 13 is a schematic diagram of an electro-optic column according to one embodiment.

[0030] Figure 14 is a schematic diagram of an electro-optic column according to one embodiment.

[0031] Figure 15 is a schematic diagram of an electro-optic column according to one embodiment.

[0032] Figure 16 is a schematic diagram of a multi-column device according to one embodiment.

[0033] Figure 17 is a schematic diagram of a multi-column device according to one embodiment.

[0034] Figure 18 is a schematic diagram of a multi-column device according to one embodiment.

[0035] Figure 19 is a schematic diagram of a multi-column device according to one embodiment.

[0036] Examples of these exemplary embodiments will now be described in detail with reference to the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise indicated, the same numbers in different figures denote the same or similar elements. The embodiments set forth in the following description of the exemplary embodiments do not represent all embodiments of the invention. Instead, they are merely examples of apparatuses and methods conforming to the nature of the invention as described in the appended claims. Implementation

[0037] The physical size of devices and the computing power of electronic devices can be reduced by significantly increasing the packing density of circuit components (such as transistors, capacitors, diodes, etc.) on IC chips. This has been achieved through increased resolution, enabling the fabrication of smaller structures. Semiconductor IC manufacturing is a complex and time-consuming process with hundreds of individual steps. Errors in any step of the IC chip manufacturing process can adversely affect the functionality of the final product. A single defect can cause device failure. Improvements in overall process yield are necessary. For example, to achieve a 75% yield in a 50-step process (where steps can indicate the number of layers formed on the wafer), each individual step must have a yield greater than 99.4%. If individual steps have a yield of 95%, the overall process yield will be as low as 7% to 8%.

[0038] Maintaining high substrate (i.e., wafer) yield (defined as the number of substrates processed per hour) is also necessary. High process yield and high substrate yield can be affected by the presence of defects. This is especially true if operator intervention is required to inspect for defects. High-yield detection and identification of micron and nanometer-scale defects using inspection tools such as scanning electron microscopes ("SEM") are necessary to maintain high yield and low cost of IC chips.

[0039] A Scanning Electron Array (SEM) comprises scanning devices and detector devices. The scanning devices include: an illumination device containing an electron source for generating primary electrons; and a projection device for scanning a target, such as a substrate, using one or more focused primary electron beams. The primary electrons interact with the target and produce interaction products, such as secondary electrons and / or backscattered electrons. The detector device captures the secondary electrons and / or backscattered electrons from the target while scanning, allowing the SEM to produce an image of the scanned area of ​​the target. Electro-optical tools embodying these SEM characteristics can be designed with a single beam. To achieve higher throughput, such as for inspection, some designs use multiple focused primary electron beams, i.e., multi-beams. The constituent beams of a multi-beam array can be called sub-beams or fine beams. Multi-beam arrays can scan different parts of the target simultaneously. Therefore, compared to single-beam detection devices, multi-beam detection devices can detect targets more quickly, for example, by moving the target at a higher speed.

[0040] In multi-beam detection apparatuses, some of the paths of the primary electron beams are displaced from the central axis of the scanning device, i.e., the midpoint of the main electro-optical axis (also referred to herein as the charged particle axis). To ensure that all electron beams arrive at the sample surface at substantially the same angle of incidence, it is necessary to manipulate sub-beam paths with a larger radial distance from the central axis through a larger angle than sub-beam paths with paths closer to the central axis. This stronger manipulation can introduce aberrations that result in a blurred and out-of-focus image. An example is spherical aberration, which introduces the focal point of each sub-beam path into different focal planes. Specifically, for sub-beam paths not on the central axis, the change in focal plane in the sub-beam is greater with radial displacement from the central axis. When detecting secondary electrons from the target, these aberrations and defocusing effects remain associated with these secondary electrons from the target; for example, the shape and size of the spot formed by the sub-beams on the target will be affected. These aberrations thus degrade the quality of the resulting image during detection.

[0041] The following describes the implementation of a known multi-beam detection device.

[0042] The figures are schematic. Therefore, for clarity, the relative dimensions of the components in the figures are exaggerated. In the following description of the figures, the same or similar reference numerals refer to the same or similar components or entities, and only describe differences with respect to individual embodiments. Although this specification and figures are directed to electro-optical devices, it should be understood that the embodiments are not intended to limit the invention to specific charged particles. References to electrons and related items throughout this document can therefore be more generally considered to be references to charged particles and related items, wherein charged particles are not necessarily electrons.

[0043] Referring now to Figure 1, which is a schematic diagram illustrating an exemplary charged particle beam detection device 100. The detection device 100 of Figure 1 includes a vacuum chamber 10, a loading and locking chamber 20, an electro-optic column 40 (also referred to as an electron beam tool), an equipment front-end module (EFEM) 30, and a controller 50. The electro-optic column 40 is located within the vacuum chamber 10.

[0044] EFEM 30 includes a first loading port 30a and a second loading port 30b. EFEM 30 may include additional loading ports. The first loading port 30a and the second loading port 30b may, for example, receive a front-opening unit cassette (FOUP) containing a substrate to be tested (e.g., a semiconductor substrate or a substrate made of other materials) or a target (the substrate, wafer, and sample are collectively referred to as the "target" below). One or more robotic arms (not shown) in EFEM 30 transport the target to the loading locking chamber 20.

[0045] Loading-lock chamber 20 is used to remove gas surrounding the target. Loading-lock chamber 20 can be connected to a loading-lock vacuum pump system (not shown), which removes gas particles from loading-lock chamber 20. Operation of the loading-lock vacuum pump system allows the loading-lock chamber to reach a first pressure below atmospheric pressure. Main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas molecules from main chamber 10, causing the pressure around the target to reach a second pressure below the first pressure. After reaching the second pressure, the target is conveyed to an electro-optic column 40 for target detection. Electro-optic column 40 may include a single-beam electro-optic device or a multi-beam electro-optic device.

[0046] The controller 50 is electronically connected to the electro-optic column 40. The controller 50 may be a processor (such as a computer) configured to control the charged particle beam detection device 100. The controller 50 may also include a processing circuitry configured to perform various signal and image processing functions. Although the controller 50 is shown in FIG. 1 as being external to a structure including the main chamber 10, the loading and locking chamber 20, and the EFEM 30, it should be understood that the controller 50 may be part of that structure. The controller 50 may be located in one of the components of the charged particle beam detection device or may be distributed above at least two of the components. While the present invention provides an example of a main chamber 10 housing an electron beam detection tool, it should be noted that the nature of the invention, in its broadest sense, is not limited to a chamber housing an electron beam detection tool. In fact, it should be understood that the foregoing principles can also be applied to other tools and other configurations of the device operating under a second pressure.

[0047] Referring now to Figure 2, which is a schematic diagram of an exemplary multi-beam electro-optic column 40 of the detection device 100 of Figure 1. In an alternative embodiment, the detection device 100 is a single-beam detection device. The electro-optic column 40 may include an electron source 301, a beamformer array 372 (also referred to as a gun aperture plate, coulomb aperture array, or pre-beam forming aperture array), a condenser lens 310, a source converter (or micro-optical array) 320, an objective lens 331, and a target 308. In one embodiment, the condenser lens 310 is magnetic. The target 308 may be supported by a support on a stage. The stage may be motorized. The stage moves so that the target 308 is scanned by accompanying electrons. The electron source 301, the beamformer array 372, and the condenser lens 310 may be components of the illumination device included in the electro-optic column 40. The source converter 320 (also referred to as the source conversion unit) and the objective lens 331, which are described in more detail below, may be components of the projection device included in the electro-optic column 40.

[0048] An electron source 301, a beamformer array 372, a condenser lens 310, a source converter 320, and an objective lens 331 are aligned with the main electro-optic axis 304 of the electro-optic column 40. The electron source 301 can generate a primary beam 302 substantially along the electro-optic axis 304 using source crossing (virtual or real) 301S. During operation, the electron source 301 is configured to emit electrons. Electrons are extracted or accelerated by an extractor and / or an anode to form the primary beam 302.

[0049] The beamformer array 372 cuts peripheral electrons from the primary electron beam 302 to reduce the resulting Coulomb effect. The primary electron beam 302 can be trimmed by the beamformer array 372 into a specified number of sub-beams, such as three sub-beams 311, 312, and 313. It should be understood that this specification is intended for use with any number of electro-optic columns 40 having any number of sub-beams (such as one, two, or more than three). The beamformer array 372 is configured in operation to block peripheral electrons to reduce the Coulomb effect. The Coulomb effect can increase the size of each of the detector spots 391, 392, and 393, and thus degrade detection resolution. The beamformer array 372 reduces aberrations caused by Coulomb interactions between electrons projected in the beam. The beamformer array 372 may include multiple openings for generating primary sub-beams even before the source converter 320.

[0050] Source converter 320 is configured to convert the beam transmitted by beamformer array 372 (including sub-beams, if present) into sub-beams projected toward target 308. In one embodiment, the source converter is a unit. Alternatively, the term source converter can be simply used as a collective term for a group of components used to form a fine beam from the sub-beams.

[0051] As shown in Figure 2, in one embodiment, the electro-optic column 40 includes a beam-limiting aperture array 321 having an aperture pattern (i.e., apertures configured in a formation manner) that defines the external dimensions of the fine beams (or sub-beams) projected toward the target 308. In one embodiment, the beam-limiting aperture array 321 is part of a source converter 320. In an alternative embodiment, the beam-limiting aperture array 321 is part of a system in the reverse direction of the main column. In one embodiment, the beam-limiting aperture array 321 divides one or more of the sub-beams 311, 312, and 313 into fine beams such that the number of fine beams projected toward the target 308 is greater than the number of sub-beams transmitted through the beamformer array 372. In an alternative embodiment, the beam limiting aperture array 321 maintains a number of sub-beams incident on the beam limiting aperture array 321, in which case the number of sub-beams may be equal to the number of fine beams projected toward the target 308.

[0052] As shown in Figure 2, in one embodiment, the electro-optic column 40 includes a pre-bending deflector array 323 having pre-bending deflectors 323_1, 323_2, and 323_3 for bending sub-beams 311, 312, and 313, respectively. The pre-bending deflectors 323_1, 323_2, and 323_3 can bend the paths of the sub-beams 311, 312, and 313 onto the beam-limiting aperture array 321.

[0053] The electro-optic column 40 may also include an imaging element array 322 having imaging deflectors 322_1, 322_2, and 322_3. Individual deflectors 322_1, 322_2, and 322_3 are associated with the path of each sub-beam. The deflectors 322_1, 322_2, and 322_3 are configured to deflect the path of the sub-beam toward the electro-optic axis 304. The deflected sub-beams form a virtual image (not shown) of the source crossing 301S. In the current embodiment, these virtual images are projected onto a target 308 via an objective lens 331, forming probe spots 391, 392, and 393 on the target. The electro-optic column 40 may also include an aberration compensator array 324 configured to compensate for aberrations that may exist in each of the sub-beams. In one embodiment, the aberration compensator array 324 includes lenses configured to operate on the individual sub-beams. The lens can be in the form of a lens array. The lenses in the array can operate on different fine beams of the multiple beams. The aberration compensator array 324 can, for example, include an array of field curvature compensators (not shown) with microlenses. The field curvature compensators and microlenses can, for example, be configured to compensate for significant field curvature aberrations in individual sub-beams at detector points 391, 392, and 393. The aberration compensator array 324 may include an array of astigmatism compensators (not shown) with micro-aberration compensators. For example, the micro-aberration compensators can be controlled to operate on the sub-beams to compensate for additional astigmatism present in detector points 391, 392, and 393.

[0054] The source converter 320 may further include a pre-bending deflector array 323 having pre-bending deflectors 323_1, 323_2, and 323_3 for bending sub-beams 311, 312, and 313, respectively. The pre-bending deflectors 323_1, 323_2, and 323_3 can bend the paths of the sub-beams onto the beam-limiting aperture array 321. In one embodiment, the pre-bending micro-deflector array 323 may be configured to bend the sub-beam paths toward an orthogonal plane to the plane of the beam-limiting aperture array 321. In an alternative embodiment, the condenser lens 310 may adjust the path direction of the sub-beams onto the beam-limiting aperture array 321. The focusing lens 310 can, for example, focus (collimate) three sub-beams 311, 312, and 313 into substantially parallel beams along the main electro-optic axis 304, such that the three sub-beams 311, 312, and 313 are incident substantially perpendicularly onto the source converter 320, which may correspond to the beam-limiting aperture array 321. In such alternative embodiments, the pre-bent micro-deflector array 323 may not be necessary.

[0055] The imaging element array 322, aberration compensator array 324, and pre-bending deflector array 323 may include multiple sub-beam manipulation device layers, some of which may be in the form of an array, such as micro-deflectors, microlenses, or micro-aberration compensators. The beam path can be rotatably manipulated. Rotational correction can be applied by a magnetic lens. Alternatively, rotational correction can be achieved by existing magnetic lenses, such as those configured as condenser lenses.

[0056] In the current embodiment of the electro-optic column 40, the fine beam is deflected toward the electro-optic axis 304 by deflectors 322_1, 322_2 and 322_3 of the imaging element array 322, respectively. It should be understood that the path of the fine beam may already correspond to the electro-optic axis 304 before reaching the deflectors 322_1, 322_2 and 322_3.

[0057] Objective lens 331 focuses a fine beam onto the surface of target 308, that is, it projects three virtual images onto the target surface. The three images formed by the three sub-beams 311 to 313 on the target surface form three probe spots 391, 392, and 393 on the sample surface. In one embodiment, the deflection angles of the sub-beams 311 to 313 are adjusted to pass through or approach the focal point in front of objective lens 331 to reduce or limit off-axis aberration of the three probe spots 391 to 393. In one configuration, objective lens 331 is magnetic. Although three fine beams are mentioned, this is only an example. Any number of fine beams may be present.

[0058] The controller is configured to control one or more beams of charged particles. The term controller encompasses deflectors, lenses, and apertures. The pre-bending deflector array 323, the aberration compensator array 324, and the imaging element array 322 may be individually or in combination with each other referred to as the controller array 34 because they control one or more sub-beams or fine beams of charged particles. Lenses and deflectors 322_1, 322_2, and 322_3 may be referred to as controllers because they control one or more sub-beams or fine beams of charged particles.

[0059] In one embodiment, a beam splitter (not shown) is provided. The beam splitter may be located in the direction of flow of the source converter 320. The beam splitter may be, for example, a Wien filter comprising an electrostatic dipole field and a magnetic dipole field. The beam splitter may be positioned in the direction of the beam path between adjacent segments 32 of the shield 31 (described in more detail below). The inner surface 39 of the shield may be radially inward from the beam splitter. Alternatively, the beam splitter may be located within the shield 31. In operation, the beam splitter may be configured to apply an electrostatic force to individual electrons of the sub-beam by means of the electrostatic dipole field. In one embodiment, the electrostatic force is equal in magnitude but opposite in direction to the magnetic force applied to individual primary electrons of the sub-beam by means of the magnetic dipole field of the beam splitter. The sub-beam can therefore pass through the beam splitter at least substantially zero deflection angle and at least substantially straight. The direction of the magnetic force depends on the direction of electron motion, while the direction of the electrostatic force does not depend on the direction of electron motion. Therefore, since the secondary electrons and backscattered electrons move in roughly the opposite direction to the primary electrons, the magnetic force applied to the secondary electrons and backscattered electrons will no longer cancel the electrostatic force, and as a result, the secondary electrons and backscattered electrons moving through the beam splitter will be deflected away from the electro-optic axis 304.

[0060] In one embodiment, a secondary column (not shown) is provided, comprising detection elements for detecting a corresponding secondary charged particle beam. When the secondary beam is incident using the detection elements, these elements can generate corresponding intensity signal outputs. The outputs can be directed to an image processing system (e.g., controller 50). Each detection element may comprise one or more pixels. The intensity signal output of the detection element may be the sum of the signals generated by all pixels within the detection element.

[0061] In one embodiment, a secondary projection device and its associated electronic detection device (not shown) are provided. The secondary projection device and its associated electronic detection device can be aligned with the sub-electro-optical axis of the secondary column. In one embodiment, a beam splitter is configured 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 a plurality of detection areas of the electronic detection device. The secondary projection device and its associated electronic detection device can record and generate an image of target 308 using secondary electrons or backscattered electrons.

[0062] In one embodiment, the detection device 100 includes a single source.

[0063] Any element or assembly of elements within the electro-optic column may be replaceable or field-replaceable. One or more electro-optic components within the column (especially electro-optic components that operate or generate sub-beams, such as aperture arrays and manipulator arrays) may comprise one or more microelectromechanical systems (MEMS). The pre-bending deflector array 323 may be a MEMS. MEMS are miniaturized mechanical and electromechanical components made using microfabrication techniques. In one embodiment, the electro-optic column 40 includes an aperture, a lens, and deflectors formed as MEMS. In one embodiment, manipulators such as lenses and deflectors 322_1, 322_2, and 322_3 may be controlled passively, actively, as a whole array, individually, or as a group within the array to control the charged particle beam projected toward the target 308.

[0064] In one embodiment, the electro-optic column 40 may include alternative and / or additional components along the charged particle path, such as lenses and other components, some of which have been previously described with reference to Figures 1 and 2. Specifically, the embodiment includes an electro-optic column 40 that divides a beam of charged particles from a source into a plurality of sub-beams. A plurality of individual objectives may project the sub-beams onto the sample. In some embodiments, a plurality of condenser lenses are provided in the countercurrent direction of the objectives. The condenser lenses focus each of the sub-beams to an intermediate focal point in the countercurrent direction of the objectives. In some embodiments, a collimator is provided in the countercurrent direction of the objectives. A corrector may be provided to reduce focusing errors and / or aberrations. In some embodiments, such correctors are integrated into or located directly adjacent to the objectives. Where condenser lenses are provided, such correctors may additionally or alternatively be integrated into or located directly adjacent to the condenser lenses, and / or located in or directly adjacent to the intermediate focal point. A detector is provided to detect charged particles emitted from 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 that it faces the sample during use. The condenser lens, objective lens, and / or detector can be formed as a MEMS or CMOS device.

[0065] Figure 3 depicts an electro-optic assembly according to one embodiment of the present invention. This electro-optic assembly is used for an electro-optic column 40. The electro-optic column 40 is used to project a beam of charged particles along a beam path toward a target 308. In one embodiment, the beam path is in the axial direction of the electro-optic column 40. The axial direction corresponds to the electro-optic axis 304. Alternatively, the beam path may be angled relative to the electro-optic axis 304.

[0066] As shown in Figure 3, in one embodiment, the electro-optic component includes an electromagnetic shield 31. This electromagnetic shield is configured to surround the charged particle beam. The electromagnetic shield 31 is configured to shield the charged particle beam from electromagnetic fields external to the electromagnetic shield 31.

[0067] In the electro-optic column 40, the path of the charged particle beam is controlled by an electromagnetic field. For example, an internal electromagnetic field can be used to control the path of the charged particle beam; that is, inside the shield 31. The internal electromagnetic field is therefore predetermined in the design and operation of the electro-optic assembly. An external (i.e., stray) electromagnetic field can inappropriately deflect the charged particle beam from its intended path. Here, "external" refers to the area outside the shield. The electromagnetic shield 31 is configured to attenuate the external electromagnetic field. The electromagnetic shield 31 is configured to reduce the influence of the external electromagnetic field on the path of the charged particle beam.

[0068] In one embodiment, the electromagnetic shield 31 is configured to shield the charged particle beam from the influence of an electric field. In one embodiment, the electromagnetic shield 31 comprises a conductive material. For example, the electromagnetic shield 31 may comprise a conductive material, such as a metal, such as copper, nickel, iron, or cobalt; or a doped semiconductor; or a metal coating. This metal coating may be disposed on a metallic or non-metallic material such as plastic. The shield 31 may have a low-resistance connection to its ground connection. By using a low-ohmic material to surround the beam, the effects of stray electric fields can be attenuated. In one embodiment, the electromagnetic shield 31 is connected to a DC potential. In one embodiment, the DC potential is a ground potential. Alternatively, the DC potential may be a fixed potential different from ground to provide an electrostatic lens.

[0069] In one embodiment, the electromagnetic shield 31 is configured to shield charged particle beams from the influence of a magnetic field. In one embodiment, the electromagnetic shield 31 comprises a magnetically conductive material. For example, the electromagnetic shield 31 may comprise an alloy. The alloy may comprise nickel and / or iron and / or cobalt. In one embodiment, the electromagnetic shield 31 comprises one or more rare earth elements. In one embodiment, the electromagnetic shield 31 comprises a material having a relative permeability of at least 5,000, 10,000, at least 20,000, at least 50,000, and at least 100,000. In one embodiment, the electromagnetic shield 31 is heat-treated. In one embodiment, the electromagnetic shield 31 undergoes a magnetic annealing process. In one embodiment, the electromagnetic shield 31 is heated in a hydrogen atmosphere.

[0070] As shown in Figure 3, in one embodiment, the electromagnetic shield 31 comprises a plurality of segments 32. The segments 32 of the electromagnetic shield 31 extend at different locations along the beam path. In the orientation shown in Figure 3, the beam path extends from top to bottom. Figure 3 shows three segments 32. The middle segment 32 extends along a portion of the beam path in the downstream direction of the shown top segment 32 and in the upstream direction of the shown bottom segment 32. Each segment 32 is configured to surround a beam of charged particles. The beam can be multiple beams.

[0071] As shown in Figure 3, in one embodiment, segment 32 of the electromagnetic shield 31 is separable. By making segment 32 separable, it is easier to disassemble and / or replace one or more parts of the electro-optical column 40. Parts of the electro-optical column 40 can be removed individually. Segments 32 can be removed individually to remove and / or replace parts of the electro-optical column 40. It is anticipated that one embodiment of the present invention will make it easier to maintain the electro-optical column 40.

[0072] In Figure 3 (and in several other figures), the electromagnetic shield 31 is shown symmetrically positioned around the beam path. In practice, the origin and direction of the external stray field may be unknown. The symmetrical electromagnetic shield 31 can have a predetermined attenuation factor regardless of the direction of the stray field. However, symmetrically positioning the electromagnetic shield 31 around the beam path is not necessary for this invention. The electromagnetic shield can be positioned off-center from the beam path. In some cases, the direction of the external field may be known (e.g., because the source of the field is known). In one embodiment, the electromagnetic shield 31 is designed to attenuate the field effect in one direction more than in another.

[0073] As shown in Figure 3, in one embodiment, segment 32 is configured such that gaps 33 in the electromagnetic shield 31 are formed between adjacent segments 32 in the direction of the beam path. For example, two gaps 33 are shown between three segments 32. These three exemplary segments may be referred to as the countercurrent segment 32' of the middle segment 32 and the downstream segment 32'' of the middle segment 32. As shown in Figure 3, in one embodiment, segment 32 is configured such that at least one segment 32 (e.g., the middle segment 32) can move radially in the direction of the beam path independently of the other segment 32 (e.g., the countercurrent segment 32' and the downstream segment 32''). In the orientation shown in Figure 3, the radial direction is the left-right direction, that is, traversing between the vertical sides of the page. In one embodiment, one of the segments 32 can be displaced independently of the other segment 32 in an angled (preferably perpendicular to the beam path) direction. In one embodiment, segment 32 may be displaced independently of the other segment 32 in a direction angled to the direction perpendicular to the beam path.

[0074] One embodiment of the invention is expected to facilitate easier removal and / or replacement of the portion along the middle of the electro-optic column 40. Disassembly and assembly can be accomplished by moving segment 32 in a direction angled to and, where applicable, perpendicular to the beam path. Disassembly and assembly are also possible by moving segment 32 in the direction of the beam path, for example, by removing segments one by one. The gap 33 allows segment 32 to be moved more easily, independently (e.g., without contacting or interfering with) other segments 32, into or out of the beam path. In one embodiment, the shield 31 includes an aperture through which the beam path extends. In one embodiment, the aperture has a size of at least 2 mm, and, where applicable, at least 5 mm, in a direction perpendicular to the beam path. In one embodiment, the beam has a size of approximately 1 mm to 2 mm. The beam is fitted into the aperture before and after replacing segment 32 of the shield 31.

[0075] As shown in Figure 3, in one embodiment, adjacent segments 32 have opposing surfaces 34. The opposing surface 34 of one segment faces the opposing surface 34 of the adjacent segment 32 of the electromagnetic shield 31. The opposing surfaces 34 are configured to extend in a direction away from the beam path, preferably radially to the beam path. The opposing surfaces 34 of adjacent segments 32 may be parallel. In the configuration shown in Figure 3, the opposing surfaces 34 of the top and middle segments 32 preferably extend further in the radial direction than the opposing surfaces 34 of the middle and bottom segments 32. In one embodiment, the opposing surfaces 34 define the extent of the gap 33 in the direction of the beam path.

[0076] In one embodiment, the opposing surface 34 preferably extends radially away from the beam path by a distance at least as large as the gap 33 between adjacent segments 32. As shown in FIG3, the gap 33 between the top segment 32 and the middle segment 32 has a distance D1. The distance D1 is measured in the direction of the beam path. The opposing surface 34 on either side of the gap 33 preferably extends radially away from the beam path by a width W1. The width W1 is measured in a radial direction that may be perpendicular to the beam path. The width W1 is measured from the inner surface of the segment 32 to the radial outer edge of the opposing surface 34. In one embodiment, W1 ≥ D1. That is, the width W1 may be greater than or equal to the distance D1.

[0077] As shown in Figure 3, the gap 33 between the bottom section 32 and the middle section 32' has a distance D2 in a direction parallel to the beam path. The opposing surface 34 on either side of the gap 33 extends with a width W2 in a radial direction, for example, relative to the beam path. In one embodiment, W2 ≥ D2. That is, the width W2 may be greater than or equal to the distance D2.

[0078] The radial extent of the opposing surface 34 can help the segment 32 attenuate the effects of stray electromagnetic fields. Generally, increasing the radial extent of the opposing surface 34 relative to the size of the gap 33 reduces the effects of stray electromagnetic fields. In one embodiment, the opposing surface 34 extends radially by a distance at least twice the size of the gap 33 between adjacent segments 32. In one embodiment, the opposing surface 34 extends radially by a distance at least three times the size of the gap 33 between adjacent segments 32. In one embodiment, the opposing surface 34 extends radially by a distance at least four times the size of the gap 33 between adjacent segments 32. In one embodiment, the opposing surface 34 extends radially by a distance at least five times the size of the gap 33 between adjacent segments 32.

[0079] In the configuration shown in Figure 3, the opposing surfaces 34 on either side of the gap 33 extend equidistantly in the radial direction. However, this is not necessarily the case. In an alternative embodiment, the opposing surfaces 34 on either side of the gap 33 may extend differently in the radial direction. In one embodiment, the shorter distance between the two opposing surfaces 34 extends at least as much in the radial direction as (or twice, three times, four times, or five times) the size of the gap 33. It is anticipated that one embodiment of the invention will reduce the influence of stray electromagnetic fields on the beam path. In one configuration, the opposing surfaces 34 may extend a non-uniform distance around and relative to the beam path. For example, in the opposing radial direction relative to the beam path, the opposing surfaces may extend further from the beam than in another direction.

[0080] As shown in Figure 3, in one embodiment, at least one end of segment 32 in the direction of the beam path includes a flange 35 extending radially in the direction of the beam path. In one embodiment, flange 35 includes an opposing surface 34. In one embodiment, the electromagnetic shielding preferably opens radially away from the beam path. Flange 35 helps to increase the radial extent of the opposing surface 34 without excessively increasing the thickness of the electromagnetic shielding 31. By keeping the thickness of the electromagnetic shielding 31 relatively low, the material cost of the electromagnetic shielding is limited. It is anticipated that one embodiment of the present invention will reduce the influence of stray electromagnetic fields on the beam without excessively increasing manufacturing costs.

[0081] Figure 4 schematically depicts a portion of an electro-optic column 40 according to one embodiment of the present invention. As shown in Figure 4, providing a flange system is not necessary. In the configuration shown in Figure 4, the top section 32' of the electromagnetic shield 31 has a potentially constant outer diameter. The opposing surface 34 extends in the radial direction. The radial extent of the opposing surface 34 is provided by increasing the thickness of the section 32 (relative to the middle section 32). The radial extent of the opposing surface 34 is provided by the thickness of the top section 32. Therefore, the opposing surface is provided by the wall of the shield 31. That is, the shield is a tube, wherein the opposing surface corresponds to the end surface of the tube. The thickness of the tube, at least at the end where it provides the wall, can thus define the range of widths W1, W2 in the direction away from the beam path.

[0082] The intermediate section 32 shown in Figure 4 is similar to the intermediate section 32 shown in Figure 3. The bottom section 32'' shown in Figure 4 includes a flange 35. The wall thickness of the bottom section 32 is greater than that of the intermediate section 32. In the bottom section 32'', the radial extent of the opposing surface 34 is provided, partly by increasing the thickness of the bottom section 32'' (relative to the intermediate section 32) and partly by providing the flange 35.

[0083] As shown in Figure 4, in one embodiment, the electro-optic assembly includes at least one electro-optic element between adjacent segments 32 of the electromagnetic shield 31. This electro-optic element is configured to operate along the path of the beam. For example, in one embodiment, one or more deflectors 36 are disposed between adjacent segments 32. (The deflectors are shown in cross-section in the same manner as the segments). In one embodiment, one or more lenses 37 are disposed between adjacent segments 32. (Since an electrostatic lens will contain two or more plates; therefore, the lens is schematically indicated for simplicity). Other types of electro-optic elements may be positioned between adjacent segments 32. Magnetic lenses may include coils outside the shield 31 and cores positioned between adjacent segments 32. In one embodiment, the electro-optic element between segments 32 is a MEMS element. For example, the deflectors 36 and / or lenses 37 may be MEMS.

[0084] In one embodiment, the electromagnetic shield 31 is configured to extend around the path of the multiple beams. In one embodiment, the electromagnetic shield 31 includes a plurality of segments 32: an anti-current direction segment 32' in the anti-current direction of the electro-optic element; a co-current direction segment 32'' in the co-current direction of the electro-optic element; and element segments 32 associated with the electro-optic element. In one embodiment, the element segments 32 are configured to be removable from a tool having the electro-optic element. In one embodiment, small gaps exist between adjacent segments 32 along the beam path.

[0085] In the embodiment shown in Figure 4, deflector 36 acts on the beam passing through gap 33. In the embodiment shown in Figure 4, deflector 36 is positioned radially outward from the outer extent of segment 32. In an alternative embodiment, deflector 36 may be positioned at least partially inward from the outer radial extent of segment 32. The outer radial extent of segment 32 may correspond to a length surface that may be parallel to the direction of the beam path. In one embodiment, deflector 36 is in gap 33, for example, between opposing surfaces 34 defining gap 33. Positioning deflector 36 closer to the beam due to shield 31 reduces undesirable attenuation of the effect of deflector 36 on the beam. In one embodiment, deflector 36 is in line with the inner surface 39 of segment 32. In one embodiment, deflector 36 is closer to the beam path than the inner surface 39 of segment 32.

[0086] As shown in Figure 4, in one embodiment, lens 37 extends radially outward beyond the radially inner edge of segment 32 of electromagnetic shielding 31. The outer periphery of lens 37 is within gap 33. In one embodiment, lens 37 is a lens array. Alternatively, an array of deflectors or apertures may be positioned between adjacent segments 32.

[0087] Figure 5 depicts a portion of an electro-optic column 40 according to one embodiment. As shown in Figure 5, in one embodiment, the electro-optic column 40 includes a module 405. In one embodiment, the module 405 includes an electro-optic component. The module 405 may include a segment 32 of an electromagnetic shield 31. As shown in Figure 5, in one embodiment, the module 405 includes an electro-optic element 38. In one embodiment, the electro-optic element 38 includes one or more manipulators, such as apertures, deflectors, and lenses. The electro-optic element 38 may be an array of manipulators. In one embodiment, the electro-optic element is a MEMS element. As shown in Figure 5, in one embodiment, the segment 32 within the module 405 is open. The electro-optic element includes a surface portion of an opposing surface 34 of the segment 32 facing either side of the electro-optic element 38.

[0088] In the module 405 shown in Figure 5, two segments 32 of an electromagnetic shield 31 are provided. An electro-optic element 38 is located between these segments 32. Gap distances D3 and D4 are formed between the segments 32 and surface portions, which are the surfaces of the electro-optic element 38 facing the opposing surfaces of the segments 32 in the direction of the beam path. The opposing surfaces of the segments 32 define the corresponding gaps by means of the opposing surface portions. The opposing surfaces that define the gaps by the surface portion gaps extend by distances W3 and W4 in the radial direction, respectively. In one embodiment, W3 is at least as large as D3. In one embodiment, W3 is twice (or three, four, or five times) the size of D3. In one embodiment, W4 is at least as large as D4. In one embodiment, W4 is twice (or three, four, or five times) the size of D4.

[0089] In one embodiment, module 405 includes an electro-optic component on a stage that allows actuation for positioning the component. In one embodiment, module 405 includes a stage. In one configuration, the stage and module may be an integral part of electro-optic column 40. In one configuration, module 405 is confined to the stage and its supported electro-optic devices. In one configuration, the stage is removable. In an alternative design, module 405 including the stage is removable. A portion of the electro-optic column 40 for module 405 is separable, i.e., a portion of the electro-optic column 40 is defined by a valve in the counter-current direction and a valve in the forward current direction of module 405. These valves can be operated to isolate the environment between the valves from the vacuum in the counter-current and forward current directions of the valves, thereby enabling the removal of module 405 from electro-optic column 40 while maintaining the vacuum in the counter-current and forward current directions of the column portion associated with module 405. In one embodiment, module 405 includes a stage. The stage is configured to support the electro-optic device relative to the beam path. In another embodiment, module 405 includes one or more actuators. These actuators are associated with the stage. The actuators are configured to move the electro-optic device relative to the beam path. In one embodiment, the actuators are located outside an electromagnetic shield 31. In another embodiment, a segment 32 of the electromagnetic shield 31 associated with the electro-optic device is disposed on either side of the stage.

[0090] When the electro-optic device can be aligned relative to the beam path by an actuator, at least one of the segments 32 associated with the electro-optic device can be actuated. In one embodiment, one or more actuators are configured to actuate segments 32 of the electromagnetic shield 31 relative to the frame of the electro-optic column 40. The frame may be associated with the stage of the module 405. In one embodiment, segment 32 is actuated relative to the stage of the module 405. In one embodiment, segment 32 is fixed relative to the electro-optic device. At least one of the shielded segments 32 may be actuated together with electro-optical devices within the module 405, which may be MEMS.

[0091] In one embodiment, module 405 is a MEMS module. In one embodiment, module 405 is configured to be replaceable within the electro-optic column 40. In one embodiment, module 405 is configured to be field-replaceable. Field-replaceable means that the module can be removed and replaced with the same or a different module while maintaining the vacuum at the location of the electro-optic column. Only the column section corresponding to the module is vented for the module to be removed, returned, or replaced.

[0092] In one embodiment, module 405 includes an internal electro-optic shield. The module can be removed, inserted, or replaced without retracting the electromagnetic shield 31 along the beam path. Segment 32 does not need to be axially movable. In conventional configurations, the shield is a continuous tube that needs to be removed or a series of continuous segments that need to be mechanically disassembled starting at one or the other end of the electro-optic column.

[0093] Figure 6 depicts a portion of the electro-optic column 40. As shown in Figure 6, in one embodiment, the final segment 32''' of the electromagnetic shield 31 in the counter-current direction of the target 308 includes an opposing surface 34. This opposing surface 34 faces the target 308. The opposing surface 34 is positioned at a distance D5 from the target 308. The distance D5 is in the direction of the beam path. The opposing surface 34 extends a width W5 away from the beam path (preferably radially relative to the beam path). The width W5 is measured perpendicular to the beam path. As shown in Figure 6, in one embodiment, segment 32 includes a flange 35. Alternatively, as described above, the radial extent of the opposing surface 34 can be provided by having a thicker wall of the electromagnetic shield 31.

[0094] In one embodiment, W5 is at least as large as D5. In another embodiment, W5 is twice (or three, four, or five times) the size of D5. As shown in Figure 6, in one embodiment, target 308 extends radially at least to the width W5. Target 308 can facilitate the attenuation of the effects of stray electromagnetic fields on the beam.

[0095] Figure 7 schematically depicts a portion of an electro-optic column 40 according to one embodiment. Figure 7 schematically illustrates the radial position of the electromagnetic shield 31 relative to other components of the electro-optic column 40. The surface of the target 308 may extend away from the beam path, or if it extends beyond the outer periphery of the target 308, the surface of the target support may extend away from the beam path. In one embodiment, the surfaces of the target and / or the target support may extend away from the beam path, at least up to the opposing surface 34 of the final segment 32.

[0096] As shown in Figure 7, in one embodiment, the electro-optic column 40 includes a thermal regulator 204. The thermal regulator 204 is configured to thermally regulate at least a portion of the electro-optic column 40. In one embodiment, the thermal regulator 204 includes a plurality of thermal regulation channels. These channels may contain a regulating fluid configured to exchange heat with one or more other portions of the electro-optic column 40. In one embodiment, the thermal regulator 204 is configured to remove heat generated within the electro-optic column. Alternatively, the thermal regulator 204 may have a mode that provides heat to the electro-optic column 40. In one embodiment, the thermal regulator 204 is configured to deliver heat to different portions of the detection tool 100. In one embodiment, the thermal regulator is configured to thermally regulate a portion of the electro-optic column 40 such that it is maintained at a stable temperature.

[0097] As shown in Figure 7, in one embodiment, the electromagnetic shield 31 is radially inward from the thermal regulator 204. The electromagnetic shield 31 is configured to shield the beam from electromagnetic fields, including those generated by the thermal regulator 204.

[0098] As shown in Figure 7, in one embodiment, the electro-optic column 40 includes at least one pump 220. The pump 220 is configured to control the pressure within the electro-optic column 40. In one embodiment, the pump 220, for example, a pumping unit of the pump 220, may be connected to a negative pressure system to reduce the pressure within the electro-optic column 40, for example, to generate and maintain a vacuum at the location where the column 40 is positioned. In one embodiment, the pump 220, for example, an exhaust valve of the pump 220, may be connected to an overpressure system to increase the pressure at the location where the electro-optic column 40 is positioned.

[0099] As shown in Figure 7, in one embodiment, the electromagnetic shield 31 extends radially inward from the pump 220 regarding the beam path. The electromagnetic shield 31 is configured to shield the beam from the electromagnetic field generated by the pump 220.

[0100] As shown in Figure 7, in one embodiment, the electro-optic column 40 includes electro-optic elements, such as a collimator 5. The collimator 5 is configured to at least partially collimate the charged particle beam. Under the operation of the collimator 5, the beam path may be in the direction of an idealized beam path, or at least the beam path may be less divergent or even convergent. In one embodiment, the electro-optic column 40 includes electro-optic elements, such as a deflector. The deflector may be configured to deflect the charged particle beam.

[0101] As shown in Figure 7, in one embodiment, the inner surface 39 of the electromagnetic shield 31 extends radially inward from an electro-optic element such as a collimator 5. The collimator 5 acts on the beam. The collimator 5 is positioned such that the electromagnetic field it generates affects the beam along the beam path. The collimator 5 is positioned between two adjacent segments 32 of the electromagnetic shield 31.

[0102] In the configuration shown in Figure 7, the collimator 5 extends radially outward from the radially inner surface 39 of the electromagnetic shield 31. In an alternative embodiment, a portion of the collimator 5 (e.g., the radially inner edge of the collimator 5) is positioned at the same radial location as the radially inner surface 39 of at least one of the segments 32 adjacent in the counter-current or co-current direction. Positioning the collimator 5 at the same distance from or close to the inner surface 39 of the adjacent segment relative to the beam path helps reduce the likelihood that the electromagnetic shield 31 will cause inappropriate attenuation of the collimator 5's effect on the beam.

[0103] Figure 8 schematically depicts a portion of an electro-optic column 40 according to one embodiment. Figure 8 schematically illustrates the alternative radial position of the electromagnetic shield 31 relative to other components of the electro-optic column 40.

[0104] As shown in Figure 8, in one embodiment, the electromagnetic shield 31 is radially inward from the thermostat 204 and the pump 220. The electromagnetic shield 31 is radially outward from electro-optic elements such as the collimator 5. As shown in Figure 8, in one embodiment, the gap 33 between adjacent sections 32 allows for fluid connection between the pump 220 and the volume close to and even including the electro-optic axis 304 within the electromagnetic shield 31. As illustrated in Figures 7 and 8, by specifying that the pump 220 is outside the electromagnetic shield 31, greater design freedom is provided for the pump 220 because electro-optic properties (e.g., voltage, current) are shielded from beam interference. By specifying that the pump 220 is outside the electromagnetic shield 31, it may not be necessary for the pump 220 to meet such high electro-optic requirements, thereby increasing design freedom. By specifying that the pump 220 is at a certain distance from the electromagnetic shield 31, the risk of vibration transmitted from the pump 220 to the column 40 can be reduced. Such vibration can negatively affect the performance of the electro-optic column 40.

[0105] Since the electromagnetic device is located within shielding 31 and has a power supply from outside shielding 31, the routing to the device is designed to minimize the electromagnetic field generated within shielding 31. For example, since two routing connections need to be made to the electrodes of the electromagnetic device (to complete the circuit), these routings are placed close to each other so that the electromagnetic fields generated by these routings substantially cancel each other out. Therefore, if the electromagnetic device is an array, the routing to each electrode for each opening in the array is designed such that the routing is positioned together with its opposite routing, so that any generated electromagnetic fields substantially cancel each other out.

[0106] Figure 9 schematically depicts a portion of an electro-optic column 40 according to one embodiment. Figure 9 schematically illustrates the alternative radial position of the electromagnetic shield 31 relative to other components of the electro-optic column 40.

[0107] As shown in Figure 9, in one embodiment, the electromagnetic shield 31 is radially inward from the thermal regulator 204. The electromagnetic shield 31 is radially outward from the pump 220 and electro-optical elements such as the collimator 5. By directing the pump 220 radially inward from the electromagnetic shield 31, the vacuum surrounding the beam can be improved.

[0108] As shown in Figure 9, in one embodiment, a lens or lens array 37 is disposed between adjacent segments 32. Other types of electro-optic elements may be positioned between adjacent segments 32. In one embodiment, the electro-optic elements between segments 32 are MEMS elements. For example, deflector 36 and / or lens 37 may be MEMS. Lens 37 may be positioned in the gap 33 between adjacent segments 32. In one configuration, a plurality of manipulators may be present between adjacent segments 32. The plurality of manipulators may include multiple manipulators of the same type, such as lenses, deflectors, or aberration compensators, and / or may include different types of manipulators, such as lenses, deflectors, and / or correctors. Different manipulators may include element arrays. A corrector array containing a plurality of correctors may be provided. A collimator array containing a plurality of collimators may be provided.

[0109] Figure 10 schematically depicts a portion of an electro-optic column 40 according to one embodiment. Figure 10 schematically illustrates the alternative radial position of the electromagnetic shield 31 relative to other components of the electro-optic column 40.

[0110] As shown in Figure 10, in one embodiment, the electromagnetic shield 31, the self-heating regulator 204, the pump 220, and the electro-optical elements (such as the collimator 5) are radially outward. Variations of this configuration may include a pump 220 located outside the shield 31. Different configurations of the controller described in Figure 9 can be applied to these configurations.

[0111] Figure 11 depicts an electro-optic assembly as part of an electro-optic column 40 according to one embodiment. As shown in Figure 11, in one embodiment, at least two of the segments 32 include adjacent ends that are electromagnetically engaged with each other. In one configuration, the electromagnetic engagement between adjacent segments 32 is non-contact. A gap may exist between the proximal surfaces of adjacent segments 32. The segments 32 are combined to shield the beam from stray electromagnetic fields. The segments 32 are electromagnetically engaged such that stray electromagnetic fields cannot affect the beam within the shield 31.

[0112] As shown in Figure 11, in one embodiment, adjacent ends are configured coaxially by a predetermined dimension. Alternatively, if, for example, it is necessary to adapt the electromagnetic shield 31 to a specific shape space within the electro-optic column 40, the segment 32 may be non-axial. It is not necessary for the shield to be configured symmetrically around the beam path.

[0113] As shown in Figure 11, in one embodiment, adjacent ends are sized such that one end can be inserted into the other. In one embodiment, adjacent segments 32 overlap along the beam path. As shown in Figure 11, an overlap 11 can be formed between adjacent segments 32 in the direction of the beam path. This overlap ensures that external electromagnetic fields do not improperly affect (such as deflect) the beam from the beam path.

[0114] In one embodiment, the adjacent ends of adjacent segments 32 are physically separated from each other. In another embodiment, the adjacent ends are electromagnetically engaged with each other. Segments 32 are movable in the direction of the beam path. Segments 32 can be removed or replaced one by one to maintain a portion of the electro-optic column 40.

[0115] In one configuration, the electromagnetic shield 31 includes different types of segments 32, such as segments with gaps between adjacent segments and segments coaxially engaged with adjacent segments. In this configuration, the shield 31 may include segments within a module that can be removed from the electro-optic column 40. In this configuration, a segment may be adapted at one end to coaxially engage with an adjacent segment, and at its other end has a facing surface that faces the opposing surface of the adjacent segment.

[0116] In one embodiment, the electromagnetic shield 31 described herein can be applied to a tool characterized by one or more MEMS electro-optic elements, such as a MEMS objective lens.

[0117] As described above, in one embodiment, the electro-optic column 40 may include alternative and / or additional components along the charged particle path, such as lenses and other components, some of which have been previously described with reference to Figures 1 and 2. Specifically, the embodiment includes an electro-optic column 40 that generates a plurality of sub-beams from an originative beam of charged particles. In one embodiment, an electromagnetic shield 31 is configured to surround all sub-beams at a given location in the electro-optic column 40. In an alternative embodiment, a separate surrounding electromagnetic shield 31 is provided for each sub-beam. In one embodiment, an electromagnetic shield 31 is provided to a group of sub-beams in the multiple beams, preferably a series of segments 32. In one embodiment, groups of sub-beams are assigned to the multiple beams such that the multiple beams include groups of sub-beams. The groups of sub-beams may have a designed shield 31 that includes a series of segments along and around the paths of the respective groups of sub-beams.

[0118] In one embodiment, the electromagnetic shield 31 has a circular cross-section. Alternatively, the cross-sectional shape may be rectangular or square, or a rectangle or a square with rounded corners.

[0119] In, for example, Figures 3 to 5, all sections 32 have the same inner diameter. Alternatively, the inner diameters of different sections can be different. This can help reduce the volume of the electromagnetic shielding 31.

[0120] In one embodiment, segments 32 are concentrically aligned along the beam path. In an alternative embodiment, one or more of segments 32 may be offset relative to each other. This can result in a magnetic lensing effect on the beam.

[0121] In one embodiment, separate electrostatic and magnetic shielding elements are provided. The electrostatic shielding element is configured to shield the beam from electrostatic fields. The magnetic shielding element is configured to shield the beam from magnetic fields. The electrostatic shielding element may have the features described above for electromagnetic shielding element 31. The magnetic shielding element may have the features described above for electromagnetic shielding element 31. In one embodiment, the magnetic shielding element is radially outward from the electrostatic shielding element. Alternatively, the magnetic shielding element may be radially inward from the electrostatic shielding element. In another configuration, the magnetic and magnetic shielding elements may be combined in a set of shielding elements.

[0122] As described above, in one embodiment, a secondary pillar (not shown) is provided, which includes a detection element for detecting a corresponding secondary charged particle beam. In one embodiment, an electro-optic assembly including an electromagnetic shield may be provided as part of the secondary pillar. For example, the source and / or detector of the secondary pillar may have the electromagnetic shield described above, except as specified herein. The shield does not need to extend in the reverse direction of the source. The shield does not need to extend in the forward direction of the detector. In one embodiment, the Wayne filter is housed by a shield 31 having Y-shaped segments. The Y-shaped segments may comprise a plurality of segments, which simplifies manufacturing and assembly. In one embodiment, the segments have flanges as described above. In one embodiment, the segments are field-replaceable. In an alternative embodiment, the flanges may be used to bolt the segments to a frame or bolt them together.

[0123] Figure 12 is a schematic diagram of an electro-optic column 4 according to one embodiment. As shown in Figure 12, in one embodiment, a plurality of segments 32a to 32d of an electromagnetic shielding member 31 are provided. These segments 32a to 32d are disposed at different positions along a direction parallel to the beam path. These different segments 32a to 32d correspond to different portions of the electro-optic column 40.

[0124] For example, in one embodiment, the first segment 32a corresponds to the source portion of the electro-optic column 40. The source portion of the electro-optic column 40 extends from the source 301. The source 301 is configured to generate a primary beam 302 of charged particles. As shown in FIG12, in one embodiment, the cross-sectional area of ​​the primary beam 302 is increased until the primary beam 302 is collimated. In one embodiment, the first segment 32a extends in a direction parallel to the beam path until the primary beam 302 is collimated. In one embodiment, the first segment 32a radially surrounds the source 301. Alternatively, the countercurrent end of the first segment 32a is in the forward current direction of the source 301. The forward current end of the first segment 32a is in the countercurrent direction of the collimator configured to collimate the primary beam 302.

[0125] In one embodiment, the second segment 32b corresponds to the collimator portion of the electro-optic column 40. The collimator portion of the electro-optic column 40 extends from the collimator. In one embodiment, the collimator includes a condenser lens 310 (e.g., as shown in FIG. 2). In one embodiment, the condenser lens 310 is magnetic. As shown in FIG. 12, in one embodiment, the cross-sectional area of ​​the collimated beam can be maintained substantially constant in the downstream direction of the collimator until the primary beam 302 is divided into sub-beams 311. In one embodiment, the second segment 32b extends in a direction parallel to the beam path until the primary beam 302 is divided. In one embodiment, the downstream end of the second segment 32b is in the downstream direction of the collimator. The second segment 32b may radially surround the collimator. Alternatively, the downstream end of the second segment 32b may be in the downstream direction of the collimator. The downstream end of the second section 32b is configured to divide the beam limiting aperture array 321 of the primary beam 302 in the upstream direction.

[0126] In one embodiment, the third segment 32c corresponds to the beam splitter portion of the electro-optic column 40. The beam splitter portion of the electro-optic column 40 extends from the component configured to form sub-beams 311 (e.g., beam-limiting aperture array 321). As shown in FIG12, in one embodiment, six sub-beams 311 may be formed in the downstream direction of the beam-limiting aperture array 321. Those skilled in the art will understand that any plurality of sub-beams may be formed, such as hundreds or thousands of sub-beams. The cross-sectional area of ​​the sub-beams 311 may remain substantially constant throughout the length of the third segment 32c. In one embodiment, the third segment 32c extends in a direction parallel to the beam path until the sub-beams 311 are focused on the target 208. In one embodiment, the downstream end of the third segment 32c is in the downstream direction of the beam-limiting aperture array 321 (or other beam splitter). The third segment 32c may radially surround the beam-limiting aperture array 321. Alternatively, the counter-current end of the third section 32c may be in the forward current direction of the beam limiting aperture array 321. The forward current end of the third section 32c may be in the counter-current direction of the objective lens configured to focus the sub-beam 311 onto the target 208.

[0127] In one embodiment, the fourth segment 32d corresponds to the objective portion of the electro-optic column 40. The objective portion of the electro-optic column 40 extends from a component configured to manipulate the sub-beam 311 incident on the target 208, such as objective lens 331 (as shown in FIG. 2). As shown in FIG. 12, in one embodiment, the sub-beam 311 is focused in the downstream direction of objective lens 331. The cross-sectional area of ​​the sub-beam 311 may be reduced via at least a portion (and in some cases all) of the length of the fourth segment 32d. In one embodiment, the fourth segment 32d extends in a direction parallel to the beam path until the sub-beam 311 is incident on the target 208. In one embodiment, the downstream end of the fourth segment 32d is in the downstream direction of objective lens 331 (or other manipulator). The fourth segment 32d may surround (e.g., radially surround) objective lens 331. Alternatively, the countercurrent end of the fourth section 32d can be in the downstream direction of objective lens 331. The downstream end of the fourth section 32d is in the countercurrent direction of target 208.

[0128] In each of the portions of the electro-optic column 40, the charged particle beam is shielded from external field influences by sections 32a to 32d of the electromagnetic shield 31. Although the four portions with four corresponding sections 32a to 32d are shown in the configuration of FIG. 12, a different number of sections 32 may exist. For example, the beam length may be divided into two, three, five, or more than five portions by using the corresponding sections 32 of the electromagnetic shield 31. In one configuration, the shielding sections may extend in the downstream direction from the beam-limiting aperture array to the objective lens array.

[0129] As explained above, segments 32 are non-overlapping in the direction parallel to the beam path. In one embodiment, the electro-optic column 40 is configured such that at least one of the portions can be replaced without disposing of or moving other portions. As described above with respect to Figures 3 and 4, in one embodiment, segment 32 opens at its end facing the gap 33 between adjacent segments 32. By providing an open end, the weakened shielding effect caused by the gap 33 can be reduced.

[0130] In one embodiment, at least one of segments 32a to 32d radially surrounds at least one component selected from the group consisting of: a charged particle source 301, a condenser lens 310, a collimator, a source converter 320, a deflector array 323, an aperture array 321, an aberration compensator array 324, an imaging element array 322, an objective lens 331, or an objective lens array and a detector array. In one embodiment, the component is a MEMS component.

[0131] In one embodiment, at least one of segments 32a to 32d is configured such that it can move independently of the other segment 32a to 32d in a radial direction along the beam path, together with the surrounding member. For example, as shown in FIG12, in one embodiment, the electro-optic column 40 includes a collimator module 405b. In one embodiment, the collimator module 405b includes a second segment 32b and a collimator. In one embodiment, the second segment 32b and the collimator have fixed positions relative to each other. The second segment 32b, together with the collimator, is field-replaceable. As shown in FIG12, in one embodiment, the electro-optic column 40 includes an objective lens module 405d. In one embodiment, the objective lens module 405d includes a fourth segment 32d and an objective lens 331 (or objective lens array). In one embodiment, the fourth segment 32d and the objective lens have fixed positions relative to each other. The fourth segment 32d, together with the objective lens, is field-replaceable.

[0132] Although not shown in Figure 12, in one embodiment, the electro-optic column 40 includes a source module and / or a beam splitter module corresponding to the source portion and beam splitter portion mentioned above, respectively.

[0133] In one embodiment, each module 405 is field-replaceable. In another embodiment, each module 405 can slide out of the electro-optic column 40 and the replacement module can slide into the electro-optic column 40. This sliding can be in a direction perpendicular to the beam path, for example, in the orientation shown in Figure 12, laterally.

[0134] By specifying that module 405 can be replaced, one embodiment of the present invention is expected to make maintaining the electro-optic column easier and / or cheaper. One embodiment of the present invention is expected to reduce the time and / or workload of removal and redoing to replace one or more components of the electro-optic column 40.

[0135] As shown in Figure 12, in one embodiment, the electro-optic column 40 includes a chimney-shaped component 52. In one embodiment, the chimney-shaped component 52 comprises the same material as section 32 of the electromagnetic shield 31. The chimney-shaped component 52 is configured to protect the beam path. For example, the chimney-shaped component 52 can electromagnetically shield the beam path. As shown in Figure 12, in one embodiment, the chimney-shaped component 52 includes, for example, a hole defined in a plane or plate, through which control lines can extend. The control lines can be used to control the electro-optic components of the electro-optic column 40. The surface of the plate defining the hole can be open.

[0136] As shown in Figure 12, in one embodiment, intentional gaps 33b to 33d are provided between adjacent sections 32a to 32d. In one embodiment, gaps 33a and 33e are provided at either end of the shield 31. In one embodiment, a first gap 33a is provided between the chimney-shaped member 52 and the first section 32a. In one embodiment, a second gap 33b is provided between the first section 32a and the second section 33b. In one embodiment, a third gap 33c is provided between the second section 32b and the third section 33c. In one embodiment, a fourth gap 33d is provided between the third section 32c and the fourth section 33d. In one embodiment, a fifth gap 33e is provided between the fourth section 32d and the target 208. One embodiment of the invention is intended to facilitate easier replacement of one or more components of the electro-optic column 40. One embodiment of the invention is intended to reduce the amount of movement of parts required to replace one or more components. Gap 33 may facilitate movement of the module 405 relative to other components of the electro-optic column 40.

[0137] As shown in Figure 12, an intentional gap 33e is provided adjacent to the target 208. One embodiment of the invention is intended to reduce the likelihood of the electromagnetic shield 31 improperly contacting the target 208. The presence of the fourth gap 33d between the third segment 32c and the fourth segment 32d allows for a nominally shorter shielding segments 32c and 32d. One embodiment of the invention is intended to reduce the likelihood of segments 32c and 32d getting stuck during assembly.

[0138] Figure 13 is a schematic diagram of an electro-optic column 40 according to one embodiment of the present invention. For simplicity, descriptions of the same features as those described above with respect to Figure 12 are omitted. As shown in Figure 13, in one embodiment, four segments 32a to 32d of an electromagnetic shield 31 are provided. These four segments 32a to 32d are for different portions of the electro-optic column 40. A first segment 32a is provided for the source portion providing the source 301. A second segment 32b is provided for the collimator portion where the beam is collimated by a collimator (e.g., a focusing lens 310). A third segment 32c is provided for the beam splitter portion where the beam is split. For example, in the embodiment shown in Figure 13, the electro-optic column 40 includes an upper beam limiter 252. 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 a counter-current 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 sub-beams from the charged particle beam emitted from the free source 301. The upper beam limiter 252 can block (e.g., absorb) portions of the beam other than those contributing to the formation of sub-beams to prevent interference with the downstream sub-beams. The upper beam limiter 252 may be referred to as a sub-beam defining aperture array.

[0139] As shown in Figure 13, in one embodiment, a control lens array 250 is present. This configuration is described in EPA filing 20196714.8, filed September 17, 2020, which, with respect to at least the electro-optical architectures shown in the three different embodiments depicted in Figures 3, 5, and 6, is hereby incorporated by reference. The control lens array 250 comprises a plurality of control lenses. Each control lens comprises at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The control lens array 250 may comprise two or more (e.g., three) plate electrode arrays connected to the respective potential sources. The control lens array 250 is associated with an 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 countercurrent direction of the objective lens array 241. The control lenses pre-focus the sub-beams (e.g., apply focusing action to the sub-beams before they reach the objective lens array 241). This pre-focusing can reduce sub-beam divergence or increase sub-beam convergence rate.

[0140] A fourth segment 32d is provided for the objective section, in which the sub-beam is manipulated to prepare its incidence on the target 208. An objective array 241 comprising a plurality of objectives is provided to guide the sub-beam onto the sample 208. Each objective includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The objective array 241 may include two or more (e.g., three) plate-shaped electrode arrays connected to the respective potential sources. As shown in FIG13, in one embodiment, the objective array 241 may include a beamforming limiter 242. The beamforming limiter 242 defines a beam-limiting aperture array. The beamforming 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 beamforming limiter 242 may include a plate (which may be a plate-shaped body) having a plurality of apertures. The beam shaping limiter 242 is positioned in the flow direction of at least one electrode (or all electrodes) of the control lens array 250. In some embodiments, the beam shaping limiter 242 is positioned in the flow direction of at least one electrode (or all electrodes) of the objective lens array 241.

[0141] Figure 14 is a schematic diagram of an electro-optic column 40 according to one embodiment of the present invention. For brevity, descriptions of the same features as those described above with respect to Figure 12 are omitted. As shown in Figure 14, in one embodiment, seven segments 32a to 32g of an electromagnetic shield 31 are provided. These seven segments 32a to 32g are for different portions of the electro-optic column 40. A first segment 32a is provided for the source portion providing the source 301. A second segment 32b is provided for the condenser portion. As shown in Figure 14, in one embodiment, a condenser lens array 231 is disposed between the source 301 and the control lens array 250. This configuration is described in EPA filing 20206984.5, filed November 11, which is hereby incorporated by reference at least regarding the electro-optic architecture shown in Figure 4. The condenser lens array 231 comprises a plurality of condenser lenses. There may be tens, hundreds, or thousands of condenser lenses. The condenser lens may comprise a multi-electrode lens and have a construction based on EP1602121A1, the contents of which are hereby incorporated by reference in particular to the disclosure of a lens array for splitting an electron beam into a plurality of sub-beams, wherein the array provides a lens for each sub-beam. A second segment 32b may surround the condenser lens array 231. The condenser lens array 231 is configured to divide the main beam into sub-beams 311 to 313.

[0142] A third segment 32c is provided for the control lens array 250. A fourth segment is provided for the objective lens portion. For example, the fourth segment 32d may surround the objective lens array 241, similar to the embodiment shown in FIG13.

[0143] As shown in Figure 14, in one embodiment, a fifth segment 32e is provided between the second segment 32b and the third segment 32c. The fifth segment 32e may surround the deflector 235. The deflector 235 is provided at the intermediate focal point. The deflector 235 is configured to bend the individual sub-beams 311 to 313 by a certain amount to effectively ensure that the main beam is substantially perpendicular (i.e., substantially 90° to the nominal surface of the sample) incident on the sample 208. The deflector 235 may also be referred to as a collimator.

[0144] As shown in Figure 14, in one embodiment, a sixth segment 32f is provided between the third segment 32c and the fourth segment 32d. The sixth segment 32f may surround the scan deflector array 260. The scan deflector array 260 includes a plurality of scan deflectors. The scan deflector array 260 may be formed using MEMS fabrication techniques. Each scan deflector causes a particular sub-beam to scan across the sample 208. The scan deflector array 260 may therefore include one scan deflector for each sub-beam. Each scan deflector may deflect the sub-beam 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-axis and Y-axis). The deflection is intended to cause the sub-beam to scan across the sample 208 in one or both directions (i.e., one-dimensionally or two-dimensionally).

[0145] As shown in Figure 14, in one embodiment, a seventh segment 32g is provided between the fourth segment 32d and the target 208. The seventh segment 32g may surround the detector module 402. The detector module 402 detects charged particles emitted from the sample 208. The detector module 402 includes a plurality of detector elements (e.g., sensor elements, such as capture electrodes). In this embodiment, the detector module 402 is disposed on the output side of the objective lens array 241. The output side is the side facing the sample 208. In variations, adjacent segments and modules may be combined. For example, the segment may surround an objective lens array assembly that may include the detector module 402, the objective lens array, a control lens array 250 (optional), and a scanning deflector (optional).

[0146] As described above with respect to the embodiments of Figures 12 and 13, in the embodiment shown in Figure 14, each segment 32a to 32g can be moved into and out of the electro-optic column 40 together with its associated components. The electro-optic column 40 is modularized. An intentional gap 33 is provided between segments 32a to 32g. This facilitates the movement of segments 32a to 32g relative to each other when they are moved into or out of the electro-optic column 40.

[0147] Figure 15 is a schematic diagram of an electro-optic column according to one embodiment of the present invention. As shown in Figure 15, in one embodiment, at least one of the segments 32 includes mechanical reference components 51c and 51d, which are configured to allow determination of the position of segment 32. In one embodiment, the mechanical reference components 51c and 51d are configured to allow determination of the position of segment 32 in a direction perpendicular to the beam path. In another embodiment, the mechanical reference components 51c and 51d are configured to allow determination of the position of segment 32 in a direction parallel to the beam path. A third segment 32c includes an associated mechanical reference component 51c. A fourth segment 32d includes associated mechanical reference components 51d and 51e. Although not shown in Figure 15, in one embodiment, the third segment 32c may include another mechanical reference component for determining the position of the third segment 32c relative to the second segment 32b. Each segment 32 may include one or more mechanical reference components 51.

[0148] In one embodiment, the mechanical reference component 51 has a fixed position relative to the associated segment 32 of the shield 31. The mechanical reference component 51 may be indirectly fixed to the associated segment 32 of the shield 31. For example, the mechanical reference component 51 may be fixed to an electro-optical component surrounding the segment 32 or to a frame to which the segment 32 is fixed. In one embodiment, the position of the component or frame is determined by the mechanical reference component 51, and the position of the segment 32 of the shield 31 is derived from its position relative to the component or frame.

[0149] In one embodiment, mechanical reference component 51c is configured to mechanically engage with another mechanical reference component 51d in segment 32d or a corresponding mechanical reference component 51d in post 40. For example, mechanical reference components 51c, 51d may include complementary surfaces configured to engage with each other. In one embodiment, these surfaces are flat. In an alternative embodiment, these surfaces are configured to define movement perpendicular to the beam path, for example, by interlocking between adjacent segments. In one embodiment, one of these surfaces includes a groove in which the complementary shape of the complementary surface is adapted. This defines lateral movement of segments 32c, 32d relative to each other. In one embodiment, these surfaces are configured to define movement in two degrees of freedom perpendicular to the beam path. For example, one of the surfaces may include a recess adapted by the hemispherical shape of the complementary surface. One of the mechanical reference components 51d may dock to another mechanical reference component 51c.

[0150] Mechanical engagement of the mechanical reference components 51 with each other is not necessary. In one embodiment, the mechanical reference components 51 include a reflective surface for reflecting radiation used in distance measurement. The distance measurement may be, for example, a measurement of the vertical position of segment 32d relative to target 208 or relative to another segment 32c. In one embodiment, the mechanical reference components 51 are used for interferometric measurements.

[0151] In one embodiment, the mechanical reference component 51 includes a conductive material and / or dielectric suitable for capacitive measurements. Capacitive measurements can be performed to indicate the position of the mechanical reference component 51 and thereby the position of the segment 32.

[0152] In one embodiment, one or more of the segments 32 are fixed in a suitable position within the post 40. In another embodiment, one or more mechanical anchor points are configured to anchor the segments 32 within the post 40. For example, rails, bolts, and / or preloaded springs are provided to control the position of the segments 32.

[0153] Figure 16 is a schematic diagram of a beam detection device 100 comprising a plurality of electro-optic columns 40. This device 100 may be referred to as a multi-column device. Figure 16 shows an embodiment of the device 100 comprising three electro-optic columns 40a to 40c. In an alternative embodiment, the device 100 comprises two, four, or more than four electro-optic columns 40.

[0154] In one embodiment, each post 40a to 40c includes a source 301a to 301c. Alternatively, two or more posts 40 may share a common source 301. In one embodiment, each post 40a to 40c has a main beam generated by sources 301a to 301c. The main beam is collimated and then divided into sub-beams 311a to 311c, 312a to 312c, and 313a to 313c, which are incident on the target 208.

[0155] As shown in Figure 16, columns 40a to 40c can be considered as being separated into different parts. Each part has corresponding segments 32a to 32c of shielding 31. In one embodiment, at least one of segments 32a to 32c radially surrounds the beam path of two or more of the electro-optic columns 40a to 40c. For example, a first segment 32a surrounds the source portion of all three columns 40a to 40c. Sources 310a to 310c are configured to generate main beams 302a to 302c for each of the individual columns 40a to 40c. A second segment 32b surrounds the collimator portion of all three columns 40a to 40c. A third segment 32c surrounds the beam splitter portion of all three columns 40a to 40c. The number of different parts and corresponding segments 32 can be two, four, five, six, seven, or more than seven; that is, as few or as many as needed.

[0156] In the embodiment shown in Figure 16, all segments 32 surround the beam path of all pillars 40. However, this is not necessarily the case. For example, one or more segments 32 may surround the beam path of only one of the pillars 40. This is illustrated in Figure 19.

[0157] As shown in Figure 16, in one embodiment, device 100 includes a source module 405a. Source module 405a includes a first segment 32a. In one embodiment, source module 405a includes sources 301a to 301c. Source module 405a can be replaced independently of other modules 405b and 405c. In one embodiment, device 100 includes a collimator module 405b. Collimator module 405b includes a second segment 32b. In one embodiment, collimator module 405b includes collimators configured to collimate one or more of the main beams 302a to 302c. Collimator module 405b can be replaced independently of other modules 405a and 405c. In one embodiment, device 100 includes a beam splitter module 405c. Beam splitter module 405c includes a third segment 32c. In one embodiment, beam splitter module 405c includes beam splitters configured to split the main beams 302a to 302c into one or more sub-beams 311 to 313. Beam splitter module 405c may be replaced independently of other modules 405a, 405b.

[0158] Figure 17 is a schematic diagram of a beam detection device 100 according to one embodiment of the present invention. The device 100 is a multi-column device. Figure 17 shows three columns 40a to 40c. In an alternative embodiment, the number of columns 40 may be two, four, or more than four.

[0159] As shown in Figure 17, in one embodiment, the device includes six segments 32 of shielding 31 for different portions of the column 40. A first segment 32a is provided for the source portion. The first segment 32a and sources 301a to 301c can be combined in a source module that can be replaced independently of other parts of the device 100. A third segment 32c is provided for the beam splitter portion. The third segment 32c and upper beam limiter 252 can be combined in a beam splitter module that can be replaced independently of other parts of the device 100.

[0160] A fifth segment 32e is provided for the collimator section, which is provided with collimator element array 271. Each collimator element collimates a separate sub-beam. The collimator element array 271 and the scanning deflector array 260 (described below) are provided together, thus providing space savings.

[0161] An eighth segment 32h is provided for the control lens portion of column 40, which is provided with control lens array 250. The eighth segment 32h and control lens array 250 can be combined in a control lens module, which can be replaced independently of other parts of device 100. Similar to the embodiment shown in FIG. 14, in one embodiment, a sixth segment 32f is provided for the scanning deflector portion of column 40. In one embodiment, the sixth segment 32f can be combined with the scanning deflector array 260 in the scanning deflector module, which can be replaced independently of other parts of device 100. Similar to the embodiment shown in FIG. 13, in one embodiment, a fourth segment 32d corresponds to the objective portion of electro-optic column 40. The fourth segment 32d can be combined with the objective lens array 241 in the objective lens module, which can be replaced independently of other parts of device 100.

[0162] Although Figure 17 shows a configuration with pillars electrostatically equivalent to the configuration shown and described with respect to Figure 13, the pillars can be any suitable electro-optical pillars such as those shown and described with respect to Figure 14. The number of shielded sections can be adjusted to accommodate the number of different modules requiring field-replaceable functionality.

[0163] Figure 18 is a schematic diagram of a beam detection device 100 according to one embodiment of the present invention. The device 100 is a multi-column device. Figure 18 shows three columns 40a to 40c. In alternative embodiments, the number of columns 40 may be two, four, or more than four, for example, twenty, one hundred, or more. For the sake of brevity, descriptions of the same features as those described above with respect to Figure 16 are omitted.

[0164] In the embodiment shown in Figure 16, the beam paths of all columns 40 are radially surrounded by segments 32. However, this is not always the case. As shown in Figure 18, in one embodiment, the beam path of at least one of the electro-optic columns 40 is radially outside of at least one of the segments 32. For example, the beam paths of the second column 40b and the third column 40c are radially outside of the first segment 32a provided for the first column 40a. In one embodiment, at least one of the segments 32 radially surrounds the beam path of only one of the electro-optic columns 40. For example, the first segment 32a for the first column 40a radially surrounds only the beam path of the first column 40a.

[0165] As shown in Figure 18, in one embodiment, different segments 32 of the electromagnetic shield 31 radially surround the beam paths of different electro-optic columns 40, and these different segments 32 are in an overlapping position in a direction parallel to the beam paths. For example, as shown in Figure 18, in one embodiment, a second segment 32b for the first column 40a radially surrounds the beam path of only the first column 40a. A third segment 32c for the first column 40a radially surrounds the beam path of only the first column 40a. A first segment 32a' for the second column 40b radially surrounds the beam path of only the second column 40b. A second segment 32b' for the second column 40b radially surrounds the beam path of only the second column 40b. A third segment 32c' for the second column 40b radially surrounds the beam path of only the second column 40b. A first segment 32a'' for the third column 40c radially surrounds the beam path of only the third column 40c. The second segment 32b'' of the third column 40c is used for radial encirclement of the beam path of the third column 40c only. The third segment 32c'' of the third column 40c is used for radial encirclement of the beam path of the third column 40c only.

[0166] As shown in Figure 18, in one embodiment, a plurality of segments 32 in overlapping positions in a direction parallel to the beam path are configured such that they can move independently of another segment 32 in a radial direction along the beam path. For example, in one embodiment, all first segments 32a, 32a', 32a'' can move together. The first segments 32a, 32a', 32a'' can be fixed relative to each other. The first segments 32a, 32a', 32a'' can be combined together in a combined source module, which can be replaced independently of other modules of device 100.

[0167] Similar to the embodiments described above and shown in Figures 12 to 17, segments 32 are provided for different portions of columns 40a to 40c. Segments 32 can be replaced independently of other segments 32. Segments 32 can be combined with corresponding components in a module that can be replaced independently of other modules. For example, as shown in Figure 18, in one embodiment, the second segment 32b'' for the third column 40c can be combined with a collimator in a collimator module 405b'' that can be replaced independently of other modules. Although not illustrated in Figure 18, in one embodiment, each segment 32 corresponds to a separate module of device 100. In variations of the embodiments shown in and described with respect to Figure 18, groups of columns can correspond to the location of each depicted column, for example, in a line with multiple columns arranged horizontally, in a grid such that each cell of the grid can have multiple columns, or both. The sections surrounding each group of columns may have the features and functions described and shown in Figure 17.

[0168] Figure 19 is a schematic diagram of a beam detection device 100 according to one embodiment of the present invention. The device 100 is a multi-column device. Figure 19 shows three columns 40a to 40c. In alternative embodiments, the number of columns 40 may be two, four, or more than four, for example, twenty-five, one hundred, or more. For the sake of brevity, descriptions of the same features as those described above with respect to Figures 16 to 18 are omitted.

[0169] In the embodiments shown in Figures 16 and 17, each segment 32 of the shield 31 surrounds the beam path of the plurality of pillars 40. In the embodiment shown in Figure 18, each segment 32 surrounds the beam path of only one pillar 40. These features are combined in the embodiment shown in Figure 19. As shown in Figure 19, in one embodiment, a single first segment 32a is provided for the source portions of the plurality of pillars 40a to 40c. Separate second segments 32b, 32b', and 32b'' are provided for the collimator portions of each of the individual pillars 40a to 40c. Separate third segments 32c, 32c', and 32c'' are provided for the beam splitter portions of each of the individual pillars 40a to 40c.

[0170] In one embodiment, each segment corresponds to a separate module that can be replaced independently. For example, as shown in FIG19, in one embodiment, the second segment 32b'' for the third column 40c can be combined with the collimator in the collimator module 405b'', which can be replaced independently of other modules.

[0171] Although not shown in Figure 19, in one embodiment, a segment 32 may be provided for a specific portion of one of the pillars 40, while another segment 32 may be provided to surround the beam path of the same type of portions of a plurality of other pillars 40. For example, a first segment 32a may surround the beam path only in the source portion of the first pillar 40a. Meanwhile, another segment 32 may surround the beam path in the source portions of both the second pillar 40b and the third pillar 40c.

[0172] As mentioned above, in one embodiment, there may be four or more pillars 40, such as nine, one hundred, or more than one hundred. In one embodiment, a first segment 32a surrounds the beam path of the source portion of the first plurality of pillars 40. Simultaneously, another segment 32 may surround the beam path of the source portion of a second plurality of pillars 40. Of course, this feature can be applied to other portions of the pillars 40, such as collimator portions.

[0173] In the variations of the configuration shown in Figure 19 and described in Figure 19, a reference to a single column may refer to a group of columns, such as in the multi-column configuration described in Figure 18.

[0174] One embodiment of the present invention is expected to achieve benefits related to a multi-beam detection beam apparatus 100. As shown in Figures 16 to 19, in one embodiment, a plurality of multi-beam columns 40 are configured to detect different positions of the same target 208 or different positions of different targets 208. In one embodiment, the electro-optic components (e.g., condenser lenses, objectives) of the columns 40 are MEMS. One embodiment of the present invention is expected to reduce and / or limit the radial range of each of the individual columns 40.

[0175] In one embodiment, the MEMS components are field-replaceable. One embodiment of the invention is intended to facilitate the maintenance of device 100 containing fragile components, such as those susceptible to contamination from particles present in ambient air.

[0176] Figures 16 to 19 show a small number of specific combinations of parts. Of course, any other combination of field-replaceable arrays and individually replaceable parts is also possible.

[0177] It is also possible to combine multiple electro-optical elements into replaceable parts of an array, such as beam splitters and micro-aberration compensators, or objectives and detectors, or objectives and detectors and height sensors for the portion of column 40.

[0178] For any of the field-replaceable parts or arrays shown above, segment 32 may be open, as described above. In one embodiment, two or more segments 32 may be combined within a replaceable module. For example, a segment 32 may be provided in the counter-current direction of the electro-optic component and a segment may be provided in the forward current direction of the electro-optic component. Segment 32 may be combined with components in the field-replaceable module.

[0179] Electro-optic columns 40 or more can be components of inspection (or metrology) tools or parts of electron beam lithography tools. Multi-beam charged particle devices can be used in a variety of applications, typically including electron microscopy (not just SEM and lithography).

[0180] Throughout the embodiment, an electro-optic axis 304 is described. This electro-optic axis 304 describes the path of charged particles through and out of source 301. Sub-beams and fine beams of the multi-beam system may all be substantially parallel to the electro-optic axis 304, at least via a manipulator. The electro-optic axis 304 may be the same as or different from the mechanical axis of the electro-optic column 40.

[0181] Although the invention has been described in conjunction with various embodiments, other embodiments of the invention will become apparent to those skilled in the art from consideration of this specification and from the practice of the invention disclosed herein. This specification and examples are intended to be illustrative only, wherein the true scope and spirit of the invention are indicated by the following claims.

[0182] The above description is intended to be illustrative and not restrictive. Therefore, it will be apparent to those skilled in the art that modifications can be made as described without departing from the scope and terms of the patent application as set forth below.

[0183] Multiple items are provided:

[0184] Clause 1: An electro-optic assembly for an electro-optic column for projecting a charged particle beam along a beam path toward a target, the electro-optic assembly comprising: an electromagnetic shield surrounding the charged particle beam path and configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield comprises a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0185] Clause 2: An electro-optical assembly as described in Clause 1, wherein the segments are configured such that a gap in the electromagnetic shield is formed between adjacent segments in the direction of the beam path.

[0186] Clause 3: An electro-optic assembly as described in Clause 2, wherein the adjacent segments have opposing surfaces that extend radially in one of the beam paths, preferably at least as large as the gap between the adjacent segments.

[0187] Clause 4: An electro-optical assembly as described in any of the preceding clauses, wherein at least one end of the segment in that direction of the beam path includes a flange extending radially in one direction of the beam path.

[0188] Clause 5: The electro-optical assembly of any of the preceding clauses includes at least one electro-optical element between adjacent segments, preferably wherein the electro-optical element includes a plurality of controllers, preferably an array of controllers.

[0189] Clause 6: An electro-optical assembly as described in any of the preceding clauses, wherein the electromagnetic shielding is configured to shield the charged particle beam from the influence of an electric field.

[0190] Clause 7: An electro-optical assembly as described in any of the preceding clauses, wherein the electromagnetic shielding is configured to shield the charged particle beam from a magnetic field.

[0191] Clause 8: An electro-optical assembly as described in any of the preceding clauses, wherein the electromagnetic shielding comprises a magnetically conductive material.

[0192] Clause 9: An electro-optical assembly as described in any of the preceding clauses, wherein the segments are configured such that at least one segment is movable radially in one direction of the beam path independently of the other of the segments.

[0193] Clause 10: An electro-optical assembly as described in any of the preceding clauses, wherein at least two of the segments comprise adjacent ends that are electromagnetically engaged with each other.

[0194] Clause 11: The electro-optical assembly as described in Clause 10, wherein the adjacent ends are configured coaxially by a predetermined dimension.

[0195] Clause 12: An electro-optical assembly as described in Clause 10 or 11, wherein the adjacent ends are sized such that one end can be inserted into the other end.

[0196] Clause 13: An electro-optical assembly as described in any of Clauses 10 to 12, wherein the adjacent ends are physically separated and electrically engaged.

[0197] Clause 14: An electro-optical assembly as described in any of the preceding clauses, wherein at least one of the segments has a mechanical reference component configured to allow determination of the position of the segment.

[0198] Clause 15: An electro-optical assembly as described in Clause 14, wherein the mechanical reference component is configured to mechanically engage with another of the segments or a corresponding mechanical reference component of the post.

[0199] Clause 16: A module comprising an electro-optic component as described in any of the preceding clauses.

[0200] Clause 17: A module comprising an electro-optic device and an electromagnetic shielding member passing through a beam path of the module when in an electro-optic column, the electro-optic column being used to project a charged particle beam along the beam path toward a target, the electromagnetic shielding member comprising an anti-current direction segment in the anti-current direction of the electro-optic device and a co-current direction segment in the co-current direction of the electro-optic device, at least one of the anti-current direction segment and the co-current direction segment having an interface extending radially in a direction of the beam path.

[0201] Clause 18: As in Clause 17, the interface of the counter-current section forms an interface with the counter-current element of the column.

[0202] Clause 19: As in Clause 18, the module wherein the countercurrent direction elements of the column include an upper beam section of the electromagnetic shield, the interface of the countercurrent direction section being configured to be spaced apart from the upper beam section by a gap when the module is present in an electro-optic column, preferably the gap being at most the same radial extent as the interface of the countercurrent direction section, preferably at least one of the countercurrent direction section and the forward direction section includes a flange extending radially in one direction of the beam path.

[0203] Clause 20: A module as described in any of Clauses 17 to 19, wherein the interface of the downstream section forms an interface with the upstream element of the column, wherein the interface of the upstream interface is a pair of opposing surfaces, and preferably the interface provides the flange.

[0204] Clause 21: As in Clause 20, the downstream elements of the column include a lower beam section of the electromagnetic shield, the interface of the downstream section being configured to be spaced apart from the lower beam section by a gap when the module is present in an electro-optic column, preferably the gap being at most the same radial extent as the interface of the downstream section.

[0205] Clause 22: A module as described in any of Clauses 17 to 21, wherein the electro-optical device is a MEMS device.

[0206] Clause 23: The module of any of Clauses 16 to 22, wherein the module is a MEMS module.

[0207] Clause 24: A module as described in any of Clauses 16 to 23, wherein the module is configured to be replaceable within the electro-optic column.

[0208] Clause 25: Modules as described in Clause 24, wherein the module is configured to be field-replaceable.

[0209] Clause 26: A module as described in any of Clauses 16 to 25 further includes a mechanical reference component configured to allow determination of the position of the module relative to the electro-optic column when in the column.

[0210] Article 27: An electro-optic column comprising a module as described in any one of Articles 16 to 25.

[0211] Article 28: An electro-optic column comprising an electro-optic component as described in any one of Articles 1 to 15.

[0212] Clause 29: An electro-optic column as described in Clause 27 or 28, wherein the electromagnetic shielding extends radially inward from one or more of the following: a thermal regulator configured to thermally adjust at least a portion of the electro-optic column; a pump configured to reduce a pressure within the electro-optic column; and an electro-optic element, such as a collimator configured to collimate the charged particle beam, or a deflector configured to deflect the charged particle beam.

[0213] Clause 30: An electro-optical assembly as described in Clause 29, wherein the thermal regulator is configured to remove heat generated within the electro-optical column.

[0214] Clause 31: An electro-optic column as described in any of Clauses 27 to 30, wherein at least one of the segments radially surrounds at least one component selected from the group consisting of: a charged particle source, a condenser lens, a collimator, a source converter, a deflector array, an aperture array, an aberration compensator array, an imaging element array, an objective lens array, and a detector array.

[0215] Clause 32: The electro-optic column as in Clause 31, wherein the component is a MEMS component.

[0216] Clause 33: An electro-optical column as in Clause 31 or 32, wherein the segment is configured such that it can move independently of the other of the segments in a radial direction along one of the beam paths, together with the surrounding member.

[0217] Clause 34: The electro-optic column of any of Clauses 31 to 33, wherein the section and the surrounding component are replaceable in the field.

[0218] Article 35: An apparatus comprising two or more of the electro-optic columns as described in any one of Articles 31 to 34.

[0219] Clause 36: The apparatus of Clause 35, wherein at least one of the segments radially surrounds the beam paths of two or more of the electro-optic columns.

[0220] Clause 37: The apparatus of Clause 35 or 36, wherein the beam path of at least one of the electro-optic columns is radially outside of at least one of the segments.

[0221] Clause 38: The apparatus of any one of Clauses 35 to 37, wherein at least one of the segments radially surrounds the beam path of only one of the electro-optic columns.

[0222] Clause 39: The apparatus of any one of Clauses 35 to 38, wherein different sections of the electromagnetic shielding radially surround the beam paths of different electro-optic columns, and the different sections are in an overlapping position in a direction parallel to one of the beam paths.

[0223] Clause 40: The apparatus of any of Clauses 35 to 39, wherein a plurality of the segments in an overlapping position in a direction parallel to one of the beam paths are configured such that they can move together with one of the segments radially in one of the beam paths independently of the other of the segments.

[0224] Clause 41: A multi-column device comprising: an electro-optic column configured to project individual charged particle beams along separate beam paths toward a target; a charged particle source configured to generate the charged particle beams for one or more of the electro-optic columns; and an electromagnetic shield surrounding the charged particle beam path of at least one of the electro-optic columns; wherein the electromagnetic shield comprises a plurality of segments extending along different positions along the separate beam paths, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0225] Clause 42: A multi-column device as described in Clause 41, wherein the columns are multi-beam columns configured to project a separate multi-beam of charged particles along separate beam paths toward the target.

[0226] Clause 43: A multi-column device as described in Clause 41 or 42, wherein the sections are configured such that a gap in the electromagnetic shield is formed between adjacent sections in the direction of the beam path.

[0227] Clause 44: A multi-column device as described in Clause 43, wherein the adjacent sections have opposing surfaces that extend radially in one of the beam paths, preferably at least as large as the gap between the adjacent sections.

[0228] Clause 45: A multi-column device as described in any of Clauses 41 to 44, wherein the segments are configured such that at least one segment is movable independently of the other segment in a radial direction along one of the beam paths.

[0229] Clause 46: A multi-column device as described in any of Clauses 41 to 45, wherein at least one of the segments has a mechanical reference component configured to allow determination of the position of the segment in a direction parallel to the beam path.

[0230] Clause 47: A multi-column device as described in any of Clauses 41 to 46, wherein at least one of the segments radially surrounds at least one component selected from the group consisting of: a charged particle source, a condenser lens array, a collimator array, a source converter, a deflector array, an aperture array, a corrector array, an aberration compensator array, an imaging element array, an objective lens array, and a detector array.

[0231] Clause 48: A multi-column device as described in any of Clauses 41 to 47, wherein the segment is configured such that it can move independently of the other of the segments in a radial direction along one of the beam paths, together with the member around which it surrounds.

[0232] Clause 49: A multi-column device as described in any of Clauses 41 to 48, wherein at least one of the segments radially surrounds the beam paths of two or more of the electro-optic columns.

[0233] Clause 50: An electro-optic assembly for an electro-optic column for projecting a charged particle beam along a beam path toward a target, the electro-optic assembly comprising: an electromagnetic shield surrounding the charged particle beam path and configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield comprises a plurality of segments extending along and surrounding the beam path, wherein at least two of the segments are separable and include adjacent ends that are electromagnetically engaged with each other.

[0234] Clause 51: An electro-optical assembly as described in Clause 50, wherein each segment defines an aperture configured for passage of the beam path.

[0235] Clause 52: An electro-optical assembly as described in Clause 50 or 51, wherein the plurality of segments extend sequentially along the beam path.

[0236] Clause 53: A method for manufacturing an electro-optic component for an electro-optic column used to project a charged particle beam along a beam path toward a target, the method comprising: providing an electromagnetic shield to surround the charged particle beam and shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield comprises a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0237] Clause 54: The method of Clause 53, wherein the electro-optic component is included in a module.

[0238] Clause 55: A method for replacing a module of an electro-optic column for projecting a charged particle beam along a beam path toward a target, the method comprising: removing the module from the electro-optic column, wherein the electro-optic column includes an electromagnetic shield surrounding the charged particle beam path and configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shield; wherein the electromagnetic shield includes a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein at least one of the segments is included in the module and separable from other segments of the module in the opposite and / or forward directions.

[0239] Clause 56: A method for projecting a charged particle beam along a beam path toward a target, the method comprising: shielding the charged particle beam from an electromagnetic field outside an electromagnetic shield; wherein the electromagnetic shield comprises a plurality of segments extending along different positions along the beam path, each segment surrounding the charged particle beam path, wherein the segments are separable.

[0240] Clause 57: The method of Clause 56 includes projecting a beam of charged particles toward the target along the beam path of each individual electro-optic column.

[0241] Clause 58: The method of Clause 57, wherein at least one of the segments surrounds two or more beam paths of the electro-optical columns and is configured such that it can move independently of the other of the segments in a radial direction in one of the beam paths, together with one or more surrounding members.

[0242] Clause 59: The method of Clause 57 or 58, wherein different segments of the electromagnetic shielding radially surround the beam paths of separate electro-optic columns, the different segments being in an overlapping position in a direction parallel to one of the beam paths and configured such that they can move independently of the other of the segments in a radial direction in one of the beam paths.

[0243] Clause 60: A method of operating an electro-optic assembly configured to project a beam of charged particles along a beam path toward a target, the assembly comprising: a plurality of electromagnetic shielding sections configured to shield the charged particle beam from an electromagnetic field outside the electromagnetic shielding; and a module comprising an electro-optic device and configured to be removable from the assembly, the method comprising: removing the module from the assembly, wherein the removal comprises radially moving a section of the electromagnetic shielding within the module relative to the beam path.

[0244] Clause 61: The method of Clause 60 further comprises replacing the module in the assembly by moving the segment of the electromagnetic shield within the module in a radial direction relative to one of the beam paths such that the segment faces the electromagnetic shield along one of the adjacent segments of the beam path within the assembly.

[0245] 5: Collimator 10: Vacuum Chamber 11: Overlapping parts 20: Loading locking chamber 30: Equipment Front-End Module (EFEM) 30a: First loading port 30b: Second loading port 31: Electromagnetic shielding components 32: Middle Section 32': Countercurrent Section / Top Section 32'': Downstream section / bottom section 32''': Section 32a: First section 32a': First segment 32a'': First segment 32b: Second section 32b': Second segment 32b'': Second segment 32c: Third segment 32c': Third segment 32c'': Third segment 32d: Fourth section 32e: Fifth section 32f: Sixth section 32g: Segment 7 32h: Section 8 33: Gap 33a: First gap 33b: Second gap 33c: Third gap 33d: Fourth gap 33e: Fifth gap 34: Opposing surface 35: Flange 36: Deflector 37: Lens / Lens Array 38: Electro-optical components 39: Radial inner surface 40: Multi-beam electro-optic column 40a: Electro-optic column 40b: Electro-optical column 40c: Electro-optical column 50: Controller 51c: Mechanical Reference Component 51d: Mechanical Reference Component 51e: Mechanical Reference Component 52: Chimney-shaped component 100: Charged particle beam detection device / beam detection device 204: Thermal Regulator 208: Target 220: Pump 231: Condensing Lens Array 235: Deflector 241: Objective lens array 242: Beam Shaping Limiter 250: Control lens array 252: Upper beam limiter 260: Scan deflector array 271: Collimator element array 301: Electronic Source 301a: Source 301b: source 301c: source 301S: Genkochi 302: Primary Beam 302a: Main Beam 302b: Main Beam 302c: Main Beam 304: Main electro-optical axis 308: Target 310: Condensing Lens 311:sub-beam 311a: Sub-beam 311b: Sub-beam 311c: sub-beam 312: sub-beam 312a: Sub-beam 312b: Sub-beam 312c: Sub-beam 313:sub-beam 313b: Sub-beam 313c: Sub-beam 320: Source Converter 321: Beam confinement aperture array 322: Imaging element array 322_1: Imaging deflector 322_2: Imaging deflector 322_3: Imaging deflector 323: Pre-bending deflector array 323_1: Pre-bending deflector 323_2: Pre-bending deflector 323_3: Pre-bending deflector 324: Aberration Compensator Array 331: Objective lens 372: Beamformer Array 391: Detecting the light spot 392: Detection Spot 393: Detecting the light spot 402: Detector Module 405a: Source Module 405b: Collimator Module 405b'': Collimator Module 405c: Beam Splitter Module 405d: Objective Lens Module D1: Distance D2: Distance D3: Distance D4: Distance D5: Distance W1: Width W2: Width W3: Distance W4: Distance W5: Width

Claims

1. A multi-column device comprising: an electro-optic column configured to project separate charged particle beams along separate beam paths toward a target, wherein the electro-optic columns are multi-beam columns configured to project a separate charged particle multi-beam along separate beam paths toward the target; a charged particle source configured to generate the charged particle beams for one or more of the electro-optic columns; and an electromagnetic shield surrounding the charged particle beam path of at least one of the electro-optic columns, wherein the electromagnetic shield comprises a plurality of segments extending at different locations along the charged particle beam path, each segment surrounding the charged particle beam path, and wherein the segments are separable.

2. The multi-column device of claim 1, wherein at least one of the segments includes a flange extending radially in one of the paths of the charged particle beam.

3. The multi-column device as claimed in claim 1, wherein the sections are configured such that a gap in the electromagnetic shield is formed between adjacent sections in the direction of the beam path.

4. The multi-column device as claimed in claim 3, wherein the adjacent sections have opposing surfaces that extend radially in one of the beam paths.

5. The multi-column device as claimed in claim 4, wherein the adjacent segments extend in a radial direction along one of the beam paths by a distance at least as large as the gap between the adjacent segments.

6. The multi-column device of claim 1, wherein the segments are configured such that at least one segment is movable radially in one direction of the beam path independently of the other of the segments.

7. The multi-column device of claim 1, wherein at least one of the segments has a mechanical reference component configured to allow determination of the position of the segment in a direction parallel to the beam path.

8. The multi-column device of claim 1, wherein at least one of the sections radially surrounds at least one charged particle optical component.

9. The multi-column device of claim 8, wherein the at least one charged particle optical element is an electro-optic element selected from the group consisting of: a charged particle source, a condenser lens array, a collimator array, a source converter, a deflector array, an aperture array, a corrector array, an aberration compensator array, an imaging element array, an objective lens array, and a detector array.

10. The multi-column device of claim 1, wherein the segment is configured such that it can move independently of the other of the segments in a radial direction along one of the beam paths, together with the at least one charged particle optical component it surrounds.

11. The multi-column device of claim 1, wherein at least one of the segments radially surrounds the beam paths of two or more of the electro-optic columns.

12. A charged particle optical evaluation apparatus comprising a multi-column device as claimed in any one of claims 1 to 11.

13. A charged particle optical lithography apparatus comprising a multi-column device as claimed in any one of claims 1 to 11.

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