Electrooptical module

Abstract

A charged particle optical module (41) for directing charged particles along a path towards a sample location, the charged particle optical module comprising a plurality of planar elements or electrodes (61 to 64) arranged across the path and configured to operate on the charged particles; a thermal conditioning channel 80 spaced apart from the planar element in a direction through the plurality of elements; and a thermally conductive plate (61 to 64; 240); 75), the heat conducting plate (61 to 64; 240); 75) connected to the thermal conditioning channel for transferring heat towards the thermal conditioning channel; wherein the thermally conductive plate extends between the planar elements and the thermal conditioning channel in a direction parallel to one or more of the planar elements.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to EP application 22200380.8 filed on October 7, 2022, the entire contents of which are incorporated by reference. Technical Field

[0003] Embodiments provided herein generally relate to a charged particle optics module, a charged particle optics apparatus, a charged particle optics device, and a method for regulating the temperature of one or more components of a charged particle optics module. Background Art

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

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

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

[0007] Another application of electron optical devices (or columns) is photolithography. A beam of charged particles reacts with a resist layer on the surface of a substrate. By controlling the location on the resist layer towards which the charged particle beam is directed, a desired pattern in the resist can be produced.

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

[0009] During use of some electron-optical devices, energy from the electron beam(s) heats the electron-optical elements. Regulating the temperature of components of an electron-optical device can be difficult. Summary of the invention

[0010] The present invention provides a suitable architecture to achieve improved control of temperature within an electron-optical device.

[0011] According to a first aspect of the present invention, a charged particle optical module for guiding charged particles along a beam path toward a sample position is provided, the charged particle optical module comprising a plurality of planar elements arranged across the beam path and configured to operate on the charged particles; a thermal regulation channel separated from the planar elements in a direction passing through the plurality of elements; and a heat conducting plate connected to the thermal regulation channel for transferring heat toward the thermal regulation channel; wherein the heat conducting plate extends between the planar elements and the thermal regulation channel in a direction parallel to one or more of the planar elements.

[0012] According to a second aspect of the present invention, a method for regulating the temperature of one or more components of a charged particle optical module is provided, the charged particle optical module being used to guide charged particles along a beam path toward a sample position, the method comprising: arranging a plurality of planar elements across the beam path to operate on the charged particles, for example, installing the module into a charged particle optical device of a charged particle optical apparatus; separating a thermal regulation channel from the planar elements in a direction passing through the plurality of elements; and transferring heat toward the thermal regulation channel via a thermal conductive plate connected to the thermal regulation channel; wherein the thermal conductive plate extends between the planar elements and the thermal regulation channel in a direction parallel to one or more of the planar elements.

[0013] According to a third aspect of the present invention, a method for regulating the temperature of one or more components of a charged particle optical module is provided, the charged particle optical module being used in a charged particle optical device to guide charged particles along a beam path toward a sample position, the charged particle optical module comprising a plurality of planar elements configured to operate on the charged particles; a thermal regulation channel separated from the plurality of planar elements; and a heat conductive plate extending between and in thermal contact with the plurality of planar elements and the thermal regulation channel, the method comprising: operating the charged particle optical device to project the charged particles to the sample position; causing a thermal regulation fluid to flow through the thermal regulation channel; and transferring heat toward the thermal regulation channel through the thermal conductive plate.

[0014] Advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which certain embodiments of the invention are set forth by way of illustration and example. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other aspects of the present disclosure will become more apparent from the description of exemplary embodiments with reference to the accompanying drawings.

[0016] Figure 1 is a schematic diagram illustrating an exemplary electron beam inspection apparatus.

[0017] Figure 2 It is illustrated as Figure 1 Schematic diagram of an exemplary multi-beam electron optical apparatus of portions of an exemplary electron beam inspection apparatus.

[0018] Figure 3 is a schematic diagram of an exemplary electron optical device including as Figure 1 A collimator element array and a scanning deflector array of a portion of an exemplary electron beam inspection apparatus.

[0019] Figure 4 Yes Figure 3 Schematic diagram of an exemplary electron-optical device array of electron-optical devices.

[0020] Figure 5 As Figure 1 Schematic diagram of an alternative exemplary electron optical apparatus of a portion of an exemplary electron beam inspection apparatus.

[0021] Figure 6 Yes, it can be Figure 3 , Figure 4 and Figure 5 Schematic diagram of an exemplary electron-optical assembly of a portion of an electron-optical device.

[0022] Figure 7 Yes, it can be Figure 3 , Figure 4 and Figure 5 Schematic diagram of an exemplary electron-optical assembly of a portion of an electron-optical device.

[0023] Figure 8 is a schematic plan view of an exemplary electron-optical assembly.

[0024] Fig. 9 yes Figure 8 A schematic plan view of a cross-section of an exemplary electron-optical assembly is shown.

[0025] Reference is now made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, wherein the same reference numerals in different drawings represent the same or similar elements unless otherwise indicated. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the present invention. Instead, these implementations are merely examples of apparatus and methods consistent with various aspects of the present invention as described in the appended claims. DETAILED DESCRIPTION

[0026] The physical size of the device can be reduced and the computing power of the electronic device can be enhanced by significantly increasing the packaging density of circuit components (such as transistors, capacitors, diodes, etc.) on the IC chip. This has been achieved by increasing the resolution, so that even smaller structures can be made. Semiconductor IC manufacturing is a complex and time-consuming process with hundreds of individual steps. An error in any step in the IC chip manufacturing process is likely to have an adverse effect on the function of the final product. Only one defect will cause equipment failure. It is expected to increase the overall yield of the process. For example, for a 50-step process (wherein the step can indicate the number of layers formed on the wafer), in order to obtain a yield of 75%, the yield of each individual step must be greater than 99.4%. If the yield of the individual step is 95%, the total process yield will be as low as 7% to 8%.

[0027] Maintaining high substrate (i.e., wafer) yield (defined as the number of substrates processed per hour) is also desirable. The presence of defects may affect high process yield and high substrate throughput. This is especially true if operator intervention is required for detecting defects. In order to maintain high yield and low cost of IC chips, high-throughput detection and identification of micron-scale defects and nano-scale defects by inspection tools such as scanning electron microscopes ('SEM') is desired.

[0028] The scanning electron microscope comprises a scanning device and a detector device. The scanning device comprises an irradiation device, which comprises an electron source for generating primary electrons; and a projection device, which is used to scan a target such as a substrate using one or more focused beams of primary electrons. The primary electrons interact with the target and generate interaction products, such as signal particles, for example, secondary electrons and / or backscattered electrons. Secondary electrons can be considered to have an energy of up to 50 eV. Although backscattered electrons have an energy spectrum from substantially zero to the maximum energy of a charged particle device, they are generally set to electrons (or signal electrons) with an energy exceeding 50 eV. When scanning the target, the detection device captures signal particles (e.g., secondary electrons and / or backscattered electrons) from the target so that the scanning electron microscope can create an image of the scanned area of ​​the target. The design of the electron optical device that embodies these scanning electron microscope characteristics can have a single beam. For higher production volumes such as for inspection, some designs of the device use multiple focused beams of primary electrons, i.e., multiple beams. The component beams of multiple beams can be referred to as sub-beams or beam waves. Multiple beams can scan different parts of the target simultaneously. Thus, a multi-beam inspection device may inspect a target more quickly, for example, by moving the target at a higher speed than a single-beam inspection device.

[0029] In a multi-beam inspection apparatus, the paths of some of the primary electron beams are displaced away from the central axis of the scanning device (i.e., the midpoint of the primary electron optical axis (which is also referred to herein as the charged particle axis)). In order to ensure that all electron beams arrive at the sample surface at substantially the same angle of incidence, beamlet paths having a larger radial distance from the central axis need to be manipulated to move through a larger angle than beamlet paths having paths closer to the central axis. This stronger manipulation may cause aberrations that cause the resulting image to be blurred and out of focus. An example is spherical aberration, which causes the focus of each beamlet path to enter a different focal plane. Specifically, for beamlet paths that are not located on the central axis, the change in the focal plane in the beamlet is greater with radial displacement relative to the central axis. When detecting signal particles (e.g., secondary electrons) from a target, these aberrations and defocusing effects may remain associated with these signal particles (e.g., secondary electrons), for example, the shape and size of the spots formed by the beamlets on the target will be affected. Therefore, these aberrations degrade the quality of the resulting image created during the inspection.

[0030] The following describes the implementation of a known multi-beam inspection device.

[0031] The drawings are schematic. Therefore, for the sake of clarity, the relative sizes of the components in the drawings are exaggerated. Within the following description of the drawings, the same or similar reference numerals refer to the same or similar components or entities, and only the differences with respect to individual embodiments are described. Although the description and drawings relate to an electron-optical device, it should be appreciated that these embodiments are not intended to limit the present disclosure to specific charged particles. Therefore, references to electrons and terms related to electrons throughout this document may be more generally considered as references to charged particles and terms referenced with respect to charged particles, wherein the charged particles are not necessarily electrons.

[0032] Now, refer to Figure 1 , Figure 1 is a schematic diagram illustrating an exemplary electron beam evaluation apparatus or inspection apparatus 100 . Figure 1 The inspection apparatus 100 includes a vacuum chamber 10, a load lock chamber 20, an electron optical device, an equipment front end module (EFEM) 30, and a controller 50. The electron optical device 40 may be located within the vacuum chamber 10. The electron optical device may include the electron optical device 40 (which is also referred to as an electron optical device, an electron beam device, or an electron beam device) and a motorized or actuated stage.

[0033] The EFEM 30 includes a first loading port 30a and a second loading port 30b. The EFEM 30 may include additional loading ports. For example, the first loading port 30a and the second loading port 30b may receive a substrate front opening wafer box (FOUP) containing a substrate to be inspected (e.g., a semiconductor substrate or a substrate made of (multiple) other materials) or a target (substrate, wafer and sample are collectively referred to as "target" below). One or more robot arms (not shown) in the EFEM 30 transport the target to the load lock chamber 20.

[0034] The load lock chamber 20 is used to remove gas around the target. The load lock chamber 20 can be connected to a load lock vacuum pump system (not shown), which removes gas particles in the load lock chamber 20. The operation of the load lock vacuum pump system enables the load lock chamber to reach a first pressure lower than the atmospheric pressure. The main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas molecules in the main chamber 10 so that the pressure around the target reaches a second pressure lower than the first pressure. After reaching the second pressure, the target is transported to an electron optical device 40 where the target can be inspected. The electron optical device 40 may include a single beam electron optical device or a multi-beam electron optical device.

[0035] The controller 50 is electronically connected to the electron optical device 40. The controller 50 may be a processor (such as a computer) configured to control the charged particle beam inspection apparatus 100. The controller 50 may also include a processing circuit system configured to perform various signal and image processing functions. Figure 1 Controller 50 is shown as being located outside of a structure including main chamber 10, load lock chamber 20, and EFEM 30, but it should be appreciated that controller 50 may be part of the structure. Controller 50 may be located in one of the constituent elements of the charged particle beam inspection device, or controller 50 may be distributed on at least two of the constituent elements. Although the present disclosure provides an example of a main chamber 10 housing an electron beam inspection device, it should be noted that aspects of the present disclosure are not limited to chambers housing electron optical devices in their broadest sense. On the contrary, it should be appreciated that the above principles may also be applicable to other devices and other arrangements of devices operating at a second pressure.

[0036] Now, refer to Figure 2 , Figure 2 is an evaluation device (e.g. Figure 1Schematic diagram of an exemplary multi-beam electron optical device 40 of an inspection device 100 of FIG. 1 . In an alternative embodiment, the inspection device 100 is a single beam evaluation device. The electron optical device 40 may include an electron source 201, a beam former array 372 (which is also called a gun aperture plate, a Coulomb aperture array, or a pre-beamlet forming aperture array), a converging lens 310, a source converter (or micro-optical array) 320, an objective lens 331, and a target 308. In one embodiment, the converging lens 310 is magnetic. (The same characteristics as the multi-beam evaluation device may be present in the single beam evaluation device, except that the electron optical components having the array apertures 372, 320 may have a single aperture. The source converter 320 may be replaced with several electron optical components along the beam path.) 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 the incident electrons. The electron source 201, the beam former array 372, the converging lens 310 may be components of an irradiation device included in the electron optical device 40. The source converter 320 (also referred to as a source conversion unit) and the objective lens 331 described in more detail below may be components of a projection device included in the electron optical device 40.

[0037] The electron source 201, the beam former array 372, the converging lens 310, the source converter 320 and the objective lens 331 are aligned with the primary electron optical axis 304 of the electron optical device 40. The electron source 201 can generate a primary beam 302 substantially along the electron optical axis 304 and having a source crossover (virtual or real) 301S. During operation, the electron source 201 is configured to emit electrons. The electrons are extracted or accelerated by the extractor and / or the anode to form the primary beam 302.

[0038] The beam former array 372 cuts the peripheral electrons of the primary electron beam 302 to reduce the Coulomb effect that occurs therewith. The primary electron beam 302 can be trimmed into a specified number of sub-beams, such as three sub-beams 311, 312 and 313, by the beam former array 372. It should be understood that this description is intended to be applied to an electron optical device 40 having any number of sub-beams (such as one, two or more than three). The beam former array 372 is configured to block peripheral electrons in operation to reduce the Coulomb effect. The Coulomb effect can increase the size of each of the detection spots 391, 392, 393, thereby degrading the inspection resolution. The beam former array 372 reduces the aberrations produced by the Coulomb interaction between the electrons projected in the beam. The beam former array 372 may include a plurality of openings for generating primary sub-beams even before the source converter 320.

[0039] Source converter 320 is configured to convert the beam (including beamlets, if present) transmitted by beamformer array 372 into beamlets that are projected toward target 308. In one embodiment, source converter is a unit. Alternatively, the term source converter may simply be used as a collective term for a group of components for forming a beam from beamlets.

[0040] like Figure 2 As shown, in one embodiment, the electron optical device 40 includes a beam limiting aperture array 321 having an aperture pattern (i.e., apertures arranged in a configuration) that is configured to define the outer dimensions of the beam (or beamlets) projected toward the target 308. In one embodiment, the beam limiting aperture array 321 is part of the source converter 320. In an alternative embodiment, the beam limiting aperture array 321 is part of a system upstream of the beam of the main device. In one embodiment, the beam limiting aperture array 321 divides one or more of the beamlets 311, 312, 313 into beamlets so that the number of beamlets projected toward the target 308 is greater than the number of beamlets transmitted through the beam former array 372. In an alternative embodiment, the beam limiting aperture array 321 maintains the number of beamlets incident on the beam limiting aperture array 321, in which case the number of beamlets may be equal to the number of beamlets projected toward the target 308.

[0041] like Figure 2 As shown, in one embodiment, the electron optical device 40 includes a pre-bend deflector array 323 having pre-bend deflectors 323_1, 323_2 and 323_3 to respectively bend the beamlets 311, 312 and 313. The pre-bend deflectors 323_1, 323_2 and 323_3 can bend the paths of the beamlets 311, 312 and 313 onto the beam limiting aperture array 321.

[0042] The electron optical device 40 may also include an image forming element array 322 having image forming deflectors 322_1, 322_2 and 322_3. There are corresponding deflectors 322_1, 322_2 and 322_3 associated with the path of each beam wave. The deflectors 322_1, 322_2 and 322_3 are configured to deflect the path of the beam wave toward the electron optical axis 304. The deflected beam wave forms a virtual image (not shown) of the source intersection 301S. In the current embodiment, these virtual images are projected onto the target 308 through the objective lens 331 and form detection spots 391, 392, 393 on the target. The electron optical device 40 may also include an aberration compensator array 324, which is configured to compensate for the aberrations that may exist in each sub-beam in the sub-beam. In one embodiment, the aberration compensator array 324 includes a lens configured to operate on the corresponding beam wave. The lens may take the form of a lens array. The lenses in the array can operate on different beam waves of the multiple beams. The aberration compensator array 324 can, for example, include a field curvature compensator array (not shown) having, for example, microlenses. For example, the field curvature compensator and the microlenses can be configured to compensate individual sub-beams for field curvature aberrations that are evident in the detection spots 391, 392, and 393. The aberration compensator array 324 can include an astigmatism compensator array (not shown) having a micro-stigmator. For example, the micro-stigmator can be controlled to operate on the sub-beams to compensate for astigmatism aberrations that are otherwise present in the detection spots 391, 392, and 393.

[0043] The source converter 320 may further include a pre-bend deflector array 323 having pre-bend deflectors 323_1, 323_2, and 323_3 to bend the beamlets 311, 312, and 313, respectively. The pre-bend deflectors 323_1, 323_2, and 323_3 may bend the paths of the beamlets onto the beam limiting aperture array 321. In one embodiment, the pre-bend micro-deflector array 323 may be configured to bend the beamlet paths of the beamlets toward the orthogonal to the plane of the beam limiting aperture array 321. In an alternative embodiment, the converging lens 310 may adjust the paths of the beamlets onto the beam limiting aperture array 321. For example, the converging lens 310 may focus (collimate) the three beamlets 311, 312, and 313 to become substantially parallel beams along the primary electron optical axis 304, so that the three beamlets 311, 312, and 313 are substantially perpendicularly incident on the source converter 320, which may correspond to the beam limiting aperture array 321. In such an alternative embodiment, the pre-bend deflector array 323 may not be necessary.

[0044] The image forming element array 322, the aberration compensator array 324 and the pre-bend deflector array 323 may include multiple layers of beamlet steering devices, some of which may be in the form of arrays, such as micro-deflectors, micro-lenses or micro-stigmators. The beam path may be steered in a rotational manner. Rotational correction may be applied by a magnetic lens. Additionally or alternatively, rotational correction may be achieved by an existing magnetic lens such as a converging lens arrangement.

[0045] In the present example of the electron optical device 40, the deflectors 322_1, 322_2 and 322_3 of the image forming element array 322 respectively deflect the beams toward the electron optical axis 304. It should be understood that the beam paths may have corresponded to the electron optical axis 304 before reaching the deflectors 322_1, 322_2 and 322_3.

[0046] The objective lens 331 focuses the beam onto the surface of the target 308, i.e., the objective lens 331 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 detection spots 391, 392 and 393 on the target surface. In one embodiment, the deflection angles of the sub-beams 311 to 313 are adjusted to pass through or approach the front focus of the objective lens 331 to reduce or limit the off-axis aberrations of the three detection spots 391 to 393. In one arrangement, the objective lens 331 is magnetic. Although three beams are mentioned, this is only by way of example. Any number of beams may exist.

[0047] The manipulator is configured to manipulate one or more charged particle beams. The term manipulator encompasses deflectors, lenses, and apertures. Because the pre-bent deflector array 323, the aberration compensator array 324, and the image forming element array 322 manipulate one or more sub-beams or beam waves of charged particles, they can be referred to as manipulator arrays individually or in combination with each other. Because the lenses and deflectors 322_1, 322_2, and 322_3 manipulate one or more sub-beams or beam waves of charged particles, they can be referred to as manipulators.

[0048] In one embodiment, a beam splitter (not shown) is provided. The beam splitter may be downstream of the beam of the source converter 320. The beam splitter may be, for example, a Wien filter including an electrostatic dipole field and a magnetic dipole field. The beam splitter may be upstream of the beam of the objective lens 331. The beam splitter may be positioned between adjacent sections of a shield (described in more detail below) in the direction of the beam path. The inner surface of the shield may be radially inward from the beam splitter. Alternatively, the beam splitter may be within the shield. In operation, the beam splitter may be configured to apply an electrostatic force to individual electrons of a beamlet through an electrostatic dipole field. In one embodiment, the electrostatic force is equal in magnitude to the magnetic force applied to the individual primary electrons of the beamlet by the magnetic dipole field of the beam splitter but opposite in direction. Therefore, the beamlet may pass through the beam splitter at least substantially straight with at least substantially zero deflection angle. The direction of the magnetic force depends on the direction of motion of the electron, while the direction of the electrostatic force does not depend on the direction of motion of the electron. Therefore, because the secondary electrons and backscattered electrons (or signal particles) move in roughly opposite directions compared to the primary electrons, the magnetic forces exerted on the secondary electrons and backscattered electrons (or signal particles) will no longer offset the electrostatic forces, and as a result, the secondary electrons and backscattered electrons moving through the beam splitter will be deflected away from the electron optical axis 304.

[0049] In one embodiment, a secondary device (not shown) is provided, which includes a detection element for detecting a corresponding secondary charged particle beam. When the secondary beam is incident on the detection element, these elements can generate a corresponding intensity signal output. The output can be directed to an image processing system (e.g., controller 50). Each detection element can include an array that can be in the form of a grid. The array can have one or more pixels; each pixel can correspond to an element of the array. The intensity signal output of the detection element can be the sum of the signals generated by all pixels in the detection element.

[0050] In one embodiment, a secondary projection device and its associated electronic detection equipment (not shown) are provided. The secondary projection device and its associated electronic detection equipment can be aligned with the secondary electron optical axis of the secondary device. In one embodiment, the beam splitter is arranged to deflect the path of the secondary electron beam toward the secondary projection device. The secondary projection device then focuses the path of the secondary electron beam onto multiple detection areas of the electronic detection device. The secondary projection device and its associated electronic detection equipment can record and generate an image of the target 308 using secondary electrons or backscattered electrons (or signal particles).

[0051] Such a Wayne filter, secondary device and / or secondary projection device can be arranged in a single beam evaluation device. In addition and / or alternatively, the detection device may be present in the beam downstream of the objective lens, for example, facing the sample during operation. In an alternative configuration, the detector device is positioned along the path of the charged particle beam toward the sample. In this arrangement, there is no Wayne filter, secondary device and secondary projection device. The detection device can be positioned at one or more positions along the path of the charged particle beam toward the sample, such as facing the sample during operation, for example, around the path of the charged particle beam. Such a detector device can have an aperture and can be annular. Different detector devices can be positioned along the path of the charged particles to detect signal particles with different characteristics. The electron optical element along the path of the charged particle beam can be arranged and controlled to focus the signal particles with different corresponding characteristics to the corresponding detector devices at different positions along the path of the charged particle beam, and the electron optical element can include one or more electrostatic plates having an aperture for the path of the charged particle beam. Such electrostatic plates may be arranged in series with two or more adjacent plates along the path of the charged particle beam.

[0052] In one embodiment, inspection apparatus 100 includes a single source.

[0053] In the electron-optical device, any element or a collection of elements may be replaceable or field replaceable. One or more electron-optical components in the electron-optical device (especially electron-optical components that operate or generate beamlets, such as aperture arrays and manipulator arrays) may include one or more micro-electromechanical systems (MEMS). The pre-bent deflector array 323 may be a MEMS. MEMS are miniaturized mechanical and electromechanical components made using micro-fabrication technology. In one embodiment, the electron-optical device 40 includes an aperture, a lens, and a deflector formed as a MEMS. In one embodiment, manipulators such as lenses and deflectors 322_1, 322_2, and 322_3 may be passively or actively controllable as an entire array, individually, or in groups within an array to control the beam wave of charged particles projected toward the target 308.

[0054] In one embodiment, the electron optical device 40 may include alternative and / or additional components on the charged particle path, such as lenses and other components, some of which have been previously described with reference to Figure 1 and Figure 2 Described in more detail later Figure 3 and Figure 4An example of such an arrangement is shown. Specifically, an embodiment includes an electron optical device 40 that divides a charged particle beam from a source into a plurality of sub-beams. A plurality of corresponding objective lenses can project the sub-beams onto a sample. In some embodiments, a plurality of converging lenses are provided upstream of the beam of the objective lens. The converging lens focuses each of the sub-beams to an intermediate focus upstream of the beam of the objective lens. In some embodiments, a collimator is provided upstream of the beam of the objective lens. A corrector can be provided to reduce focusing errors and / or aberrations. In some embodiments, such a corrector is integrated into the objective lens or positioned directly adjacent to the objective lens. Where a converging lens is provided, such a corrector can be additionally or alternatively integrated into the converging lens, or positioned directly adjacent to the converging lens, and / or located in the intermediate focus or positioned directly adjacent to the intermediate focus. A detector is provided to detect charged particles emitted by the sample. The detector can be integrated into the objective lens. The detector can be on the bottom surface of the objective lens so as to face the sample when in use. The detector can include, for example, an array of detector elements, which can correspond to an array of beam waves of a multi-beam arrangement. The detectors (or detector elements) in the detector array may generate detection signals, which may be associated with pixels of the generated image.The converging lens, the objective lens and / or the detectors may be formed as MEMS or CMOS devices.

[0055] Figure 3 is a schematic diagram of another design of an exemplary electron-optical device 40. The electron-optical device 40 may include a source 201 and one or more electron-optical components. Alternatively, the electron-optical device may include an upper beam limiter 252, a collimator element array 271, a control lens array 250, a scanning deflector array 260, an objective lens array 241, a beam shaping limiter 242, and a detector array. The source 201 provides a beam of charged particles (e.g., electrons). Multiple beams focused on the sample 208 are derived from the beam provided by the source 201. The sub-beams can be derived from the beam, for example, using a beam limiter (which defines a beam limiting aperture array). Ideally, the source 201 is a high-brightness thermal field emitter with a good compromise between brightness and total emission current.

[0056] 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 beam-upstream beam limiting aperture array. The upper beam limiter 252 may include a plate (which may be a plate-like body) having a plurality of apertures. The upper beam limiter 252 forms a beamlet from a charged particle beam emitted by the source 201. The upper beam limiter 252 may block (e.g., absorb) portions of the beam other than portions that contribute to forming the beamlet so as not to interfere with beamlets downstream of the beam. The upper beam limiter 252 may be referred to as a beamlet defining aperture array.

[0057] A collimator element array 271 is provided downstream of the upper beam limiter. Each collimator assembly collimates a corresponding sub-beam. The collimator element array 271 may be formed using MEMS manufacturing techniques so as to be spatially compact. In some embodiments, as Figure 3 As illustrated, the collimator element array 271 is the first deflection or focusing electron optical array element in the beam path downstream of the source 201. In another arrangement, the collimator can take the form of a giant collimator in whole or in part. Such a giant collimator can be upstream of the beam of the upper beam limiter 252, so that the giant collimator operates on the beam from the source before generating multiple beams. A magnetic lens can be used as a giant collimator.

[0058] There is a control lens array 250 downstream of the collimator element array. The control lens array 250 includes a plurality of control lenses. Each control lens includes at least two electrodes (e.g., two or three electrodes) connected to a corresponding potential source. The control lens array 250 may include two or more (e.g., three) plate-shaped electrode arrays connected to a corresponding potential source. The control lens array 250 is associated with the objective lens array 241 (e.g., the two arrays are positioned close to each other and / or mechanically connected to each other and / or controlled together as a unit). The control lens array 250 is located upstream of the objective lens array 241. The control lens pre-focuses the sub-beams (e.g., applies a focusing action to the sub-beams before the sub-beams reach the objective lens array 241). Pre-focusing can reduce the divergence of the sub-beams or increase the convergence rate of the sub-beams.

[0059] As mentioned, the control lens array 250 is associated with the objective lens array 241. As described above, the control lens array 250 can be considered to provide electrodes in addition to the electrodes 242, 243 of the objective lens array 241, for example, as part of the objective lens array assembly. The additional electrodes of the control lens array 250 allow other degrees of freedom to control the electron optical parameters of the beamlets. In one embodiment, the control lens array 250 can be considered to be an additional electrode of the objective lens array 241, realizing additional functions of the corresponding objective lenses of the objective lens array 241. In one arrangement, such electrodes can be considered to be part of the objective lens array, thereby providing additional functions to the objective lenses of the objective lens array 241. In this arrangement, the control lens is considered to be part of the corresponding objective lens, even to the extent that the control lens is only referred to as a part of the objective lens, for example, in providing one or more additional degrees of freedom to the objective lens. Although the control lens array 241 can be indistinguishable from the objective lens array 250 and is a part of the objective lens array 250, in this specification, the control lens array 250 is considered to be different and separate from the objective lens array 241.

[0060] For ease of illustration, the lens array is schematically depicted herein by an array of elliptical shapes. Each elliptical shape represents one of the lenses in the lens array. Conventionally, elliptical shapes are used to represent lenses, similar to the biconvex form often used in optical lenses. However, in the context of an electronic optical arrangement such as the one discussed herein, it should be understood that the lens array will typically operate electrostatically, and therefore any physical elements that may not require the use of biconvex shapes. As described above, the lens array may instead include multiple plates with apertures.

[0061] A scanning deflector array 260 comprising a plurality of scanning deflectors may be provided. The scanning deflector array 260 may be formed using MEMS manufacturing techniques. Each scanning deflector causes a corresponding beamlet to scan across the sample 208. Thus, the scanning deflector array 260 may include a scanning deflector for each beamlet. Each scanning deflector may deflect the beamlet in one direction (e.g., parallel to a single axis, such as the X-axis) or in two directions (e.g., relative to two non-parallel axes, such as the X-axis and the Y-axis). The deflection may be such that the beamlet scans across the sample 208 in one or two directions (i.e., one-dimensionally or two-dimensionally). In one embodiment, the scanning deflectors described in EP2425444 (the entire contents of which are incorporated herein by reference, particularly with respect to scanning deflectors) may be used to implement the scanning deflector array 260. The scanning deflector array 260 (e.g., formed using MEMS manufacturing techniques as mentioned above) may be more spatially compact than a giant scanning deflector. In another arrangement, a giant scanning deflector may be used upstream of the upper beam limiter 252. The giant scanning deflector may function similarly or identically to a scanning deflector array, although it operates on the beam from the source before generating beam waves of multiple beams.

[0062] An objective lens array 241 including a plurality of objective lenses is provided to direct the sub-beams onto the sample 208. Each objective lens includes at least two electrodes (e.g., two or three electrodes) connected to a corresponding potential source. The objective lens array 241 may include two or more (e.g., three) plate-shaped electrode arrays connected to the corresponding potential source. Each objective lens formed by the plate-shaped electrode array may be a microlens that operates on different sub-beams. Each plate defines a plurality of apertures (which may also be referred to as holes). The position of each aperture in the plate corresponds to the position of a corresponding aperture (or multiple apertures) in another plate (or multiple plates). The corresponding apertures define the objective lens, and each corresponding aperture set therefore operates on the same sub-beam in multiple beams when in use. Each objective lens projects a corresponding sub-beam of multiple beams onto the sample 208.

[0063] An objective lens array 241 having only two electrodes may have lower aberrations than an objective lens array 241 having more electrodes. A three-electrode objective lens may have a greater potential difference between the electrodes, thus achieving a stronger lens. Additional electrodes (i.e., more than two electrodes) provide additional degrees of freedom for controlling electron trajectories, for example, focusing secondary electrons as well as the incident beam. Such additional electrodes may be considered to form a control lens array 250. The benefit of a two-electrode lens over a single lens is that the energy of the incident beam is not necessarily the same as the outgoing beam. Advantageously, the potential difference on this two-electrode lens array enables it to be used as an accelerating lens array or a decelerating lens array.

[0064] The objective lens array may form part of an objective lens array assembly together with any or all of the scanning deflector array 260, the control lens array 250, and the collimator element array 271. The objective lens array assembly may also include a beam shaping limiter 242. The beam shaping limiter 242 defines a beam limiting aperture array. The beam shaping limiter 242 may be referred to as a lower beam limiter, a lower beam limiting aperture array, or a final beam limiting aperture array. The beam shaping limiter 242 may include a plate (which may be a plate-like body) having a plurality of apertures. The beam shaping limiter 242 is downstream of the beam from at least one electrode (optionally, all electrodes) of the control lens array 250. In some embodiments, the beam shaping limiter 242 is downstream of the beam from at least one electrode (optionally, all electrodes) of the objective lens array 241.

[0065] In one arrangement, the beam shaping limiter 242 is structurally integrated with the electrode 302 of the objective lens array 241. Ideally, the beam shaping limiter 242 is located in an area of ​​low electrostatic field strength. Each of the beam limiting apertures is aligned with a corresponding objective lens in the objective lens array 241. The alignment allows a portion of a beamlet from the corresponding objective lens to pass through the beam limiting aperture and impinge on the sample 208. The aperture of the beam shaping limiter 242 may have a smaller diameter than the aperture of at least one of the objective lens array 241, the control lens array 250, the detector array 240, and the upper beam limiter array 252. Each beam limiting aperture has a beam limiting effect, thereby allowing only a selected portion of the beamlets incident on the beam shaping limiter 242 to pass through the beam limiting aperture. The selected portion may allow only a portion of the corresponding beamlet that passes through the central portion of the corresponding aperture in the objective lens array to reach the sample. The central portion may have a circular cross-section and / or be centered on the beam axis of the beamlet.

[0066] In one embodiment, the electronic optical device 40 is configured to control the objective lens array assembly (e.g., by controlling the potential applied to the electrodes of the control lens array 250) so that the focal length of the control lens is greater than the spacing between the control lens array 250 and the objective lens array 241. Therefore, the control lens array 250 and the objective lens array 241 can be positioned relatively close together, wherein the focusing action from the control lens array 250 is too weak to form an intermediate focus between the control lens array 250 and the objective lens array 241. The control lens array and the objective lens array operate together to obtain a combined focal length to the same surface. Combined operation without an intermediate focus can reduce the risk of aberrations. In other embodiments, the objective lens array assembly can be configured to form an intermediate focus between the control lens array 250 and the objective lens array 241.

[0067] An electric power source may be provided to apply corresponding potentials to electrodes of the control lenses of the control lens array 250 and the objective lenses of the objective lens array 241 .

[0068] In addition to the objective lens array 241, a control lens array 250 is provided to provide additional degrees of freedom for controlling the properties of the sub-beams. For example, additional degrees of freedom are provided even when the control lens array 250 and the objective lens array 241 are provided relatively close together, so that no intermediate focus is formed between the control lens array 250 and the objective lens array 241. The control lens array 250 can be used to optimize the beam angle relative to the reduction rate of the beam and / or control the beam energy delivered to the objective lens array 241. The control lens may include two or three or more electrodes. If there are two electrodes, the reduction rate and the landing energy are controlled together. If there are three or more electrodes, the reduction rate and the landing energy can be controlled independently. Note that the beam-most downstream electrode of the control lens array 250 can be the beam-most upstream electrode of the objective lens array 241. That is, the control lens array 250 and the objective lens array 241 can share electrodes. The shared electrodes provide different lens effects for each lens, each lens effect relative to one of its two opposing surfaces (i.e., the beam upstream surface and the beam downstream surface). Therefore, the control lens can be configured to adjust the reduction rate and / or beam angle and / or landing energy on the substrate of the corresponding sub-beam (for example, using an electrical power source to apply a suitable corresponding potential to the electrodes of the control lens and the objective lens). This optimization can be achieved without having an excessively negative impact on the number of objective lenses and without excessively degrading the aberrations of the objective lens (for example, without reducing the strength of the objective lens). The use of a control lens array enables the objective lens array to operate at its optimal electric field strength. Note that references to reduction rate and angle are intended to refer to changes in the same parameter. In an ideal arrangement, the product of a certain range of reduction rate and corresponding angle is constant. However, the angle may be affected by the use of aperture.

[0069] In one embodiment, the landing energy can be controlled to a desired value within a predetermined range, for example, from 1000 eV to 5000 eV. Ideally, the landing energy changes primarily by controlling the energy of the electrons leaving the control lens. Preferably, the potential difference within the objective lens remains constant during this change so that the electric field within the objective lens remains as high as possible. In addition, the potential applied to the control lens can be used to optimize the beam angle and the reduction ratio. The control lens can be used to change the reduction ratio according to the change in the landing energy. Ideally, each control lens includes three electrodes to provide two independent control variables. For example, one of the electrodes can be used to control the magnification, while a different electrode can be used to independently control the landing energy. Alternatively, each control lens may have only two electrodes. When there are only two electrodes, one of the electrodes may need to control both the magnification and the landing energy.

[0070] A detector array (not shown) is provided to detect charged particles emitted from the sample 208. The detected charged particles may include any of the charged particles (e.g., signal particles) detected by the scanning electron microscope, including secondary (emitted) electrons and / or backscattered electrons from the sample 208. The detector may be an array providing a surface of an electron optical device facing the sample 208 (e.g., the bottom surface of the electron optical device). Alternatively, the detector array is upstream of the beam of the bottom surface, or, for example, in an objective lens array or a control lens array, or upstream of the beam of the objective lens array or the control lens array. The elements of the detector array may correspond to beam waves of a multi-beam arrangement. The signals generated by detecting electrons by the elements of the array are transmitted to a processor for generating an image. The signals may correspond to pixels of an image.

[0071] In other embodiments, both a giant scanning deflector and a scanning deflector array 260 are provided. In such an arrangement, scanning the beamlets across the sample surface can be achieved by controlling the giant scanning deflector and the scanning deflector array 260 together (preferably synchronously).

[0072] In one embodiment, Figure 4As illustrated, an electron optical device array 500 is provided. The array 500 may include any of the multiple electron optical devices described herein. Each electron optical device in the electron optical device focuses corresponding multiple beams onto different areas of the same sample at the same time. Each electron optical device may form a sub-beam from a beam of charged particles from different corresponding sources 201. Each corresponding source 201 may be one of the multiple sources 201. At least one subset of the multiple sources 201 may be provided as a source array. The source array may include multiple sources 201, which are provided on a common substrate. The simultaneous focusing of multiple multiple beams onto different areas of the same sample allows for simultaneous processing (e.g., evaluation) of a larger area of ​​sample 208. The electron optical devices in the array 500 may be arranged adjacent to each other so as to project corresponding multiple beams onto adjacent areas of the sample 208.

[0073] Any number of electron-optical devices may be used in array 500. Preferably, the number of electron-optical devices ranges from two (2) (ideally, nine (9)) to one hundred (100) or even two hundred (200). In one embodiment, the electron-optical devices are arranged in a rectangular array or a hexagonal array. In other embodiments, the electron-optical devices are provided in an irregular array or in a regular array having a geometric shape other than rectangular or hexagonal. When referring to a single electron-optical device, each electron-optical device in array 500 may be configured in any of the manners described herein, for example, as described above, particularly with respect to reference 500. Figure 5 The details of this arrangement are described in EPA 20184161.6, filed on July 6, 2020, which is hereby incorporated by reference, regarding how the objective lens can be incorporated and adapted for use in a multi-device arrangement.

[0074] exist Figure 4 In the example of Figure 3 A plurality of electron-optical devices of the type described. Thus, in this example, each of the electron-optical devices includes both a scanning deflector array 260 and a collimator element array 271. As mentioned above, the scanning deflector array 260 and the collimator element array 271 are particularly suitable for incorporation into the electron-optical device array 500 due to their spatial compactness, which facilitates the positioning of the electron-optical devices close to each other. This arrangement of the electron-optical devices may be preferred over other arrangements using magnetic lenses as collimators. For example, due to magnetic interference between columns, it may be challenging to incorporate a magnetic lens into an electron-optical device intended for use in a multi-device arrangement (e.g., a multi-column arrangement).

[0075] Except as described below and Figure 5In addition to the features shown, alternative designs of multi-beam electron optics may have similar characteristics to those described above. Figure 3 The same characteristics as described. An alternative design of a multi-beam electron optical device may include a converging lens array 231 upstream of the beam of the objective lens array arrangement 241, as disclosed in EP application 20158804.3 filed on February 21, 2020, which is hereby incorporated by reference for the description of a multi-beam device with a collimator and its components. Because the beam limiting aperture array associated with the converging lens array 231 can shape the beam waves 211, 212, 213 of the multiple beams from the source 201, this design does not require a beam shaping limiter array 242 or an upper beam limiter array 252. The beam limiting aperture array of the converging lens can also act as an electrode in the lens array.

[0076] The paths of the beams 211, 212, 213 diverge away from the converging lens array 231. The converging lens array 231 focuses the generated beams to an intermediate focus (i.e., toward the control lens array and the objective lens array) between the converging lens array 231 and the objective lens array assembly 241. The collimator array 271 may be located at the intermediate focus rather than being associated with the objective lens array assembly 241.

[0077] The collimator can reduce the divergence of the divergent beam paths. The collimator can collimate the divergent beam paths so that they are generally parallel toward the objective array assembly. A corrector array may be present in the multi-beam path, for example, associated with a converging lens array, an intermediate focus, and an objective array assembly. The detector 240 can be integrated into the objective 241. The detector 240 may be on the bottom surface of the objective 241 so as to face the sample when in use.

[0078] In one Figure 5 As shown and referenced Figure 5 In the embodiment of the arrangement described, the detector may be located in the electron-optical device 40 as described in reference Figure 3 The electronic optical device lock is described and as Figure 3 The detector 240 may be integrated into the objective lens array 241 and the control lens array 250 (when present, since the control lens array 250 is not in the Figure 5). The detector may have more than one detector at different locations along the path of the beamlets of the multiple beams, for example, each array being associated with a different electron-optical element (such as an electrode of an objective lens array and / or a control lens array). The objective lens array 241 and the associated electron-optical elements (such as the control lens array 250) may be included in an assembly, which may be a monolithic assembly, which may be referred to as an electron-optical assembly or an electron-optical module 41. In one embodiment, the detector 240 is associated with a planar element of the electron-optical module 41, or even integrated into a planar element of the electron-optical module 41. For example, the detector 240 may be located on the bottom surface of the electron-optical module 41 including the objective lens 241. The detector 240 may be provided with an electrical connection 60, as described elsewhere in this document. (The detector may be considered to be a plate in which a plurality of apertures are defined, ideally). In one variation, the detector has a detector array located upstream of the objective lens array (optionally and the control lens array 250) (e.g., upstream of the electron-optical module 41). Between the electron optics module 41 and the detector array may be a Wayne filter array that directs the charged particle beam in a beam downstream direction toward the sample and directs signal particles from the sample to the detector array.

[0079] The electron optical device array may have a Figure 3 The multi-beam device described and as Figure 4 Multiple multi-beam devices of this design shown. Multiple multi-beam devices can be arranged in a multi-beam device array. This arrangement is shown and described in EP application 20158732.6 filed on February 21, 2020, which is hereby incorporated by reference with respect to the multi-device arrangement of a multi-beam device, which is characterized by the disclosed design of a multi-beam device with a collimator at an intermediate focus. Another alternative design of a multi-beam device includes multiple single-beam devices. A single beam generated for the purpose of the present invention described herein may be similar to or equivalent to a multi-beam generated by a single device. Each device may have an associated detector. This multi-device device may be arranged in the form of an array of three, four, nine, nineteen, fifty, one hundred or even two hundred devices, each device generating (in the case of a single-beam device) a single beam or beam wave or (in the case of a multi-beam device) multiple beams. In this other alternative design, the device array may have a common vacuum system, each device having a separate vacuum system or a device group being assigned a different vacuum system.

[0080] Electron optics 40 may be a component of an inspection (or evaluation metrology inspection) apparatus or part of an electron beam lithography apparatus.Multi-beam charged particle apparatus may be used in several different applications including electron microscopy in general (not just scanning electron microscopy and lithography).

[0081] The electron optical axis 304 describes the path of the charged particles through the source 201 and out of the source 201. Unless explicitly mentioned, all beamlets and beamlets of the plurality of beams may be at least referred to by, for example, reference Figure 2 The manipulator or electron-optical array of the arrangement shown and described is generally parallel to the electron-optical axis 304. The electron-optical axis 304 can be the same as or different from the mechanical axis of the electron-optical device 40. Figures 2 to 5 In the context of the arrangement shown and described, the electron optical axis can correspond to the path of the center beam of the multi-beam (e.g., beam 212). The beams of the multi-beam are at a collimated position (e.g., a position of the collimator array 271 corresponding to the intermediate focal plane (e.g., as shown in FIG. Figure 5 The surface of the sample 208 (as shown) or the upper beam limiter 252) and the sample 208 are substantially parallel to each other (e.g., along the electron optical axis 304).

[0082] The electronic optical device 40 may include Figure 6 An electron optical module 41 for manipulating electron beam waves is shown. For example, the electron optical module 41 may include one or more of the following features (in a non-limiting list), which are referred to as electron optical elements: an objective lens array 241, and / or a converging lens array 231 and / or a collimator element array 271 and / or an individual beam corrector and / or a deflector and / or a Wayne filter array and / or a detector array and / or a beam limiter array. Specifically, the objective lens 331 and / or the converging lens 310 and / or the control lens 250 may include the electron optical module 41. Ideally, the electron optical module includes only electrostatic electron optical elements, such as any of the following: lens arrays 241, 231, collimator array 271, individual beam corrector array, beam limiter array, detector array and deflector array. In one embodiment, most of the electron optical elements of the electron optical module are electrostatic and may include a Wayne filter array (which may include at least one magnetic planar element array, for example, no more than one magnetic planar element). In one embodiment, all electron-optical elements of the electron-optical module comprise a planar array for operating a plurality of charged particle beams. In individual electron-optical elements, a plurality of apertures may be defined through which the respective beams pass.

[0083] The electronic optical module 41 is configured to provide a potential difference between two or more plates (or substrates). An electrostatic field is generated between the plates acting as electrodes. The electrostatic field generates an attractive force between the two plates. The attractive force may increase as the potential difference increases. One or more of the plates may include silicon.

[0084] Figure 6is a schematic diagram of an electron optical module 41. The electron optical module 41 is used to guide electrons along a beam path toward a sample location. Figure 6 In the orientation shown, the beam path runs from top to bottom down the middle of the drawing.

[0085] like Figure 6 As shown, in one embodiment, the electron optical module 41 includes a plurality of planar elements 61 to 64. Planar elements 61 to 64 are arranged to cross the beam path. In one embodiment, the beam path is substantially perpendicular to the plane of the planar elements 61 to 64. Planar elements 61 to 64 are configured to operate on electrons (i.e., electrons guided along the beam path). For example, one or more of the planar elements 61 to 64 can be electron optical elements, such as electron optical lens elements or electron optical deflector elements. In one embodiment, one or more of the planar elements 61 to 64 are planar elements other than electron optical elements. For example, in one embodiment, one or more of the planar elements 61 to 64 are configured to operate on electrons without requiring an applied voltage. For example, one or more of the planar elements 61 to 64 can be configured to limit one or more electron beams by blocking some of the electrons in the electrons. Although the term 'planar element' is incorporated into the word 'plane', it is an embodiment that the planar element is planar. In another embodiment, one or more of the planar elements may be any suitable electron optical element, for example, an electrostatic element such as an electrode and / or plate that can interact with or operate on electrons along the beam path. One or more of the planar elements may include an electron optical element. One or more of the planar elements may be an electrode for use as an electron optical element. One or more of the planar elements may include one or more electrodes to be used as an electron optical element. In one embodiment, the planar element is thermally conductive. The planar element can conduct heat away from the beam path.

[0086] like Figure 6 As shown, in one embodiment, the planar elements 61 to 64 are stacked relative to each other. The planar elements 61 to 64, 240 can be included in the stack. Figure 6 As shown, one of the planar elements may be a detector 240 or include a detector 240. The detector 240 may be configured to detect signal electrons from a sample location. The detector 240 may include one or more detector elements configured to detect electrons in, for example, a detector array. Additionally or alternatively, the stack may include one or more detectors that monitor the detector to detect one or more primary beams during operation and / or calibration of the electron optical device.

[0087] In one embodiment, two or more of the planar elements 61 to 64 are configured to be used as one or more electron optical lenses when a potential difference is applied between these planar elements. For example, the planar elements 61 to 64 can constitute an array of objective lenses 241 and / or an array of control lenses 250. In one embodiment, the electron optical module 41 is an objective lens assembly. Additionally or alternatively, the electron optical module 41 may include an array of converging lenses and / or an array of deflectors and / or an array of individual beam correctors and / or an array of beam limiting apertures. In one embodiment, one or more of the planar elements 61 to 64 include a single aperture, which is provided for multiple (optionally, all) beam paths to pass through. Such a planar element may be referred to as a giant plate.

[0088] like Figure 6 As shown, in one embodiment, the electron optical module 41 includes a thermal regulation channel 80. The thermal regulation channel 80 is spaced apart from the planar elements 61 to 64 in a direction passing through the planar elements 61 to 64. For example, when the electron optical module 41 is viewed in a direction parallel to the beam path (i.e., perpendicular to the plane of the planar elements 61 to 64), the thermal regulation channel 80 is spaced apart from the planar elements 61 to 64. Figure 6 As shown, there may be a space or gap 82 between the planar elements 61 to 64 and the thermal regulation channel 80. It is not necessary for the thermal regulation channel 80 to be separated from the planar elements 61 to 64. In an alternative embodiment, the thermal regulation channel 80 is in contact with one or more of the planar elements 61 to 64. For example, when the thermal regulation channel is made of an electrically insulating material (or a non-conductive material), the gap 82 may be omitted.

[0089] In one embodiment, the thermal regulation channel is configured to thermally regulate the electronic optical module 41. In one embodiment, the thermal regulation channel 80 is configured to accommodate a thermal regulation fluid for thermally regulating the electronic optical module 41. The thermal regulation fluid can be a liquid, such as water or a gas. In one embodiment, a fluid supplier is configured to supply the thermal regulation fluid to the thermal regulation channel 80. The thermal regulation fluid flows through the thermal regulation channel 80. Heat can be exchanged between the thermal regulation fluid in the thermal regulation channel 80 and the components of the electronic optical module 41. For example, the thermal regulation fluid can become hot and take away heat from the planar elements 61 to 64. The thermal regulation channel 80 is configured to regulate (e.g., control) the temperature of the components (such as the planar elements 61 to 64) of the electronic optical module 41.

[0090] During use of the electron optical module 41, the planar elements 61 to 64 may receive incident energy from the electron beam. This may cause the planar elements 61 to 64 to heat up. The thermal regulation channel 80 may at least partially counteract the heating of the electron optical module 41 caused by the incident electron beam.

[0091] like Figure 6 As shown, in one embodiment, the electronic optical module includes a plurality of thermal regulation channels 80. For example, Figure 6 As shown, in one embodiment, the thermal regulation channel 80 is located on opposite sides of one or more electron beams. When there are multiple electron beams, the beam paths of the electron beams can be arranged in a pattern that can be referred to as a beam grid. In one embodiment, the beam grid is located between the thermal regulation channels 80. Although Figure 6 Only two thermal regulation channels 80 are shown, but in one embodiment, the electron optical module 41 includes three, four, or more than four thermal regulation channels 80. In one embodiment, the thermal regulation channels 80 are arranged on different sides of the electron optical module 41 when viewed in a direction parallel to the beam path. In one embodiment, the thermal regulation channels 80 are in fluid communication with each other. The thermal regulation fluid flowing through one of the thermal regulation channels 80 can continue to flow through the channel network so as to flow through one or more other thermal regulation channels in the thermal regulation channels 80. Alternatively, the thermal regulation channels 80 can be independent of each other.

[0092] The thermal regulation channels 80 may be connected in parallel and / or in series. In one embodiment, the thermal regulation channels 80 extend around the electronic optical module 41. For example, one or more regulation channels 80 may extend around the electronic optical module 41 more than once, for example, multiple times. The thermal regulation channels 80 may extend in a spiral manner.

[0093] In one embodiment, one or more thermal regulating channels 80 extend around one side of the planar elements 61 to 64. In one embodiment, one or more thermal regulating channels 80 extend all the way around the planar elements 61 to 64 (eg, surround the planar elements 61 to 64 when viewed in plan).

[0094] In one embodiment, one or more thermal regulation channels 80 are connected to a planar element that has another planar element located downstream of its beam. For example, in one embodiment, one or more thermal regulation channels 80 are connected to a detector 240 located in the middle of the stack (i.e., the detector 240 is located between other planar elements of the stack). In one embodiment, one or more thermal regulation channels 80 are connected to a detector 240 that is located at the beam upstream end of the electron optical module 41.

[0095] like Figure 6 As shown, in one embodiment, the heat regulating passage 80 has a square cross section. However, it is not necessary for the cross section to be square. In one embodiment, the heat regulating passage 80 has a cross section that includes a curve (e.g., a circle or an ellipse). The curved inner surface of the passage may be more advantageous in fluid dynamics.

[0096] like Figure 6As shown, in one embodiment, the thermal regulation channel 80 is positioned to one side of the area through which the electron beam passes. The electron beam can be arranged in a relatively dense beam grid. The thermal regulation channel 80 is located outside the beam grid. The electron beam can be arranged in a relatively narrow area that is not disturbed by the thermal regulation channel 80. The thermal regulation channel 80 located outside the electron optical module 41 allows the area within the sample position that the electron beam can reach to be more continuous (i.e., there are fewer gaps between the electron beams at the sample position).

[0097] In one embodiment, the electronic optical module 41 includes a heat conducting plate. The heat conducting plate is connected to the heat regulating channel 80. The heat conducting plate is used to transfer heat toward the heat regulating channel 80. In one embodiment, the heat conducting plate is or includes a planar element such as a detector 240. In one embodiment, the heat conducting plate is or includes the detector 240. Additionally or alternatively, in one embodiment, the heat conducting plate is a spacer such as Figure 6 The detector spacer 75 shown may include a spacer such as Figure 6 Detector spacer 75 is shown. Detector spacer 75 is configured to separate detector 240 from one or more of planar elements 61 to 64. For example, in one embodiment, beam-most downstream planar element 64 located upstream of the beam of detector 240 may constitute an electrode of an array of objective lens 241. Detector spacer 75 is configured to separate detector 240 from objective lens 241. Detector spacer 75 may be thicker (in a direction parallel to the beam path) than the beam-most downstream electrode of objective lens 241. As shown in FIG. Figure 6 As shown, for example, in the direction of the beam path, there may be a narrow gap between the beam-most downstream plane element 64 of the objective lens 241 and the detector 240. That is, the size of the detector spacer in the beam path may be smaller than the other spacers 71, 72, 73, 74 of the stack. The present invention will be described below in the case where the detector 240 is a thermally conductive plate. However, the present invention is embodied by the detector spacer 75 (or another spacer) being a thermally conductive plate. In one embodiment, the thermally conductive plate includes the detector 240 and a spacer such as the detector spacer 75.

[0098] like Figure 6As shown, in one embodiment, a thermally conductive plate is connected to the downstream end of the beam of the thermal regulation channel 80. However, this is not a necessary feature. In one embodiment, a substrate such as a thermally conductive plate is connected to the upstream end of the beam of the thermal regulation channel 80. In one embodiment, a substrate (e.g., a thermally conductive plate) is connected to both the upstream end of the beam and the downstream end of the beam of the thermal regulation channel 80. In one embodiment, a thermally conductive plate such as a detector 75 is connected to the surface of the thermal regulation channel 80 that faces the beam region. For example, the detector spacer 75 may include an outer periphery that contacts the thermal regulation channel 80. The thermal regulation channel 80 may be directly connected to the detector 240.

[0099] like Figure 6 As shown, in one embodiment, the detector 240 (i.e., the heat conducting plate) extends between the planar elements 61 to 64 and the thermal regulation channel 80 in a direction parallel to one or more of the planar elements 61 to 64. When the electron optical module 41 is viewed in a direction passing through the planar elements 61 to 64, the detector 240 (i.e., the heat conducting plate) extends between the planar elements 61 to 64 and the thermal regulation channel 80. The gap 82 overlaps with the detector 240. In one embodiment, the detector 240 overlaps with the thermal regulation channel 80 when viewed in a direction parallel to the beam path. In one embodiment, the detector 240 overlaps with the planar elements 61 to 64 when the electron optical module 41 is viewed in a direction parallel to the beam path.

[0100] It is contemplated that embodiments of the present invention improve regulation of the temperature of the electronic optical module 41. The thermally conductive plate helps conduct heat toward the thermal regulation channel 80. The thermal regulation channel 80 is configured to act as a heat sink. By providing a thermally conductive plate extending between the planar elements 61 to 64 and the thermal regulation channel 80, heat conduction from the planar elements 61 to 64 to the thermal regulation channel 80 can be improved.

[0101] As mentioned above, in one embodiment, the thermally conductive plate is a planar element, such as a detector 240 for detecting signal particles from a sample position. In one embodiment, the detector 240 is a detector array, which includes an array of detectors configured to detect signal particles from a sample position. Alternatively, in one embodiment, the thermally conductive plate is connected to a planar element such as the detector 240. For example, the thermally conductive plate can be a detector spacer 75, which is connected to the detector 240.

[0102] In one embodiment, the thickness of the detector 240 in a direction parallel to the beam path is greater than or substantially equal to the thickness of one or more of the planar elements 61 to 64. In one embodiment, the thickness of the detector 240 is greater than or substantially equal to the thickness of all other planar elements 61 to 64. By increasing the thickness of the substrate of the detector 240, the heat conduction through the detector 240 toward the thermal regulation channel 80 can be increased. This helps to regulate the temperature of the planar elements 61 to 64. In one embodiment, the substrate of the detector 240 has a thickness of at least 100 μm, optionally at least 200 μm, optionally at least 300 μm. Increasing the thickness of the detector 240 can help reduce the temperature of the detector 240. Limiting the temperature of the detector 240 can help limit the thermal load (e.g., radiation load) that the detector 240 can apply to the beam upstream electron optical elements and / or the beam downstream sample 208. In one embodiment, the substrate of the detector 240 has a thickness of at most 500 μm, optionally at most 300 μm. In one embodiment, the planar elements 61 to 64 have a thickness of at least 50 μm, optionally at least 100 μm. In one embodiment, the planar elements 61 to 64 have a thickness of at most 2000 μm, optionally at most 150 μm, optionally at most 100 μm. In one embodiment, the heat conducting plate has a thickness of at least 100 μm, optionally at least 200 μm, optionally at least 300 μm.

[0103] In one embodiment, the detector 240 is configured to conduct heat generated in the detector 240 during operation toward the thermal regulation channel 80. For example, in one embodiment, the thermally conductive plate (e.g., the detector 240) includes or is connected to a component including active electronic devices (such as CMOS devices) that can operate at a lower operating potential (e.g., ~10V). Such active electronic devices can increase the heat generated in the electron optical module 41 during use of the electron optical module 41, for example, despite the lower operating potential. For example, a voltage can be applied to the active electronic device. Because, for example, the thermally conductive plate is in a vacuum, applying a voltage may cause heat to be dissipated in the thermally conductive plate (e.g., the detector 240).

[0104] For example, in one embodiment, one or more electron beams are incident on a central region 246 of the detector 240. The incident electron beam may heat the detector 240. Additionally, the detector elements within the central region 246 of the detector 240 may include active electronic devices, such as one or more CMOS devices. The active electronic devices may increase the heat generated in the detector 240. Additionally or alternatively, the detector may include other active electronic devices in a peripheral region 247 of the detector 240. The peripheral region 247 may be located outside the region through which the electron beam passes. In one embodiment, the peripheral region 247 of the detector 240 includes active electronic components, such as an analog-to-digital converter (ADC). The ADC may generate heat at the detector 240. In one embodiment, the thermally conductive plate is configured to conduct the heat generated in the central region 246 and / or the peripheral region 247 toward the thermal regulation channel 80.

[0105] In one embodiment, the thickness of the detector 240 is of a size sufficient to conduct heat generated in the detector 240 during operation toward the thermal regulation channel 80. In one embodiment, the detector 240 includes a material having a thermal conductivity sufficient to conduct heat generated in the detector 240 during operation toward the thermal regulation channel 80. In one embodiment, the material of the thermal regulation channel 80 has a thermal conductivity in a range from about 15 W / mK to about 20 W / mK. In one embodiment, the thermally conductive plate has a thermal conductivity in a range from about 50 W / mK to about 100 W / mK. It is contemplated that embodiments of the present invention reduce the operating temperature of the detector 240.

[0106] like Figure 6 As shown, in one embodiment, heat generating circuitry such as an ADC may be located in the peripheral region 247. By positioning the circuitry as close as possible to the thermal regulation channel 80, conduction of the generated heat toward the thermal regulation channel 80 may be improved. In one embodiment, the heat generating circuitry is included in one or more planar elements 61-64 other than the detector 240. For example, a planar element that is an array of individual beam correctors, an array of deflectors, or an array of correctors may include the heat generating circuitry.

[0107] exist Figure 6 In the arrangement shown, a peripheral region 247 is provided only at one side of the electron optical module 41, and heat generating circuitry such as an ADC is in the peripheral region 247. In an alternative arrangement, the circuitry can be positioned in a symmetrical manner. For example, the heat generating circuitry can be located in the peripheral region on either side of the electron beam.

[0108] During the use of the electron optical module 41, it can be expected that the main source of thermal energy is the detector 240, specifically, the beam area in the central area 246 and the circuit system in the peripheral area 247. It is expected that embodiments of the present invention improve the dissipation of thermal energy through the heat regulating channel 80 as a heat sink. The heat regulating channel 80 is configured to actively cool the electron optical module 41. Compared with passive cooling, it is expected that active cooling increases the heat removal capacity. The heat regulating channel 80 at one side of the electron optical module 41 allows the beam area to remain larger. Specifically, the individual electron beams in the multi-beam are not separated by the heat regulating channel. By isolating the heat regulating channel 80 from the planar elements 61 to 64, the possibility of electrical creep and / or electrical breakdown between the planar elements 61 to 64 and the heat regulating channel 80 can be reduced.

[0109] like Figure 6 As shown, in one embodiment, the electronic optical module 41 includes spacers 71 to 75. The spacers 71 to 75 are configured to separate the planar elements 61 to 64 and the detector 240 from each other. In one embodiment, the spacers 71 to 75 are configured to mechanically support the planar elements 61 to 64. In one embodiment, the spacers 71 to 75 are configured to electrically isolate the planar elements 61 to 64 from each other. However, it is not necessary for the spacers 71 to 75 to provide electrical insulation. For example, two adjacent planar elements can be operated at the same voltage, in which case it may not be necessary for these planar elements to be electrically isolated from each other.

[0110] Figure 7 4 is a schematic diagram of an electronic optical module 41 according to an embodiment of the present invention. Figure 6 The features of the electro-optical module 41 shown are identical to those of the electro-optical module described above, and are described in detail to avoid duplication of description. Figure 7 The characteristics shown can have Figure 6 Features that are similarly labeled are shown.

[0111] like Figure 7 As shown, in one embodiment, the gap 82 between the planar elements 61 to 64 and the thermal regulation channel 80 may be filled with a material. In one embodiment, the electronic optical module 41 includes a material 83 that electrically isolates the planar elements 61 to 64 from the thermal regulation channel 80. For example, the material 83 can be a potting material. In one embodiment, the material 83 is provided to reduce the possibility of high voltage discharge.

[0112] Embodiments of the present invention are expected to improve the heat conduction of heat energy from the electrostatic lens stack (e.g., formed by the planar elements 61 to 64) toward the thermal regulation channel 80. By providing material 83, the thermal regulation channel 80 can be positioned closer to the planar elements 61 to 64 without excessively increasing the risk of electrical breakdown between the planar elements 61 to 64 and the thermal regulation channel 80. In one embodiment, the thermal regulation channel 80 includes a conductive material, such as a metal. Such a conductive material can be mechanically rigid. Material 83 allows the active cooling provided by the thermal regulation channel 80 to be closer to the stack, i.e., closer to the planar elements 61 to 64. In an alternative embodiment, the thermal regulation channel 80 is electrically insulating. For example, the thermal regulation channel 80 can include an electrically insulating material (e.g., formed by an electrically insulating material) such as a ceramic. The ceramic can be sintered to form the channel. The sintered ceramic can be ground to reduce any errors in the shape of the ceramic after the sintering process. In one embodiment, such a process for manufacturing the thermal regulation channel 80 may be less desirable than other techniques such as three-dimensional printing because of the dimensional instability caused in the structure during sintering.

[0113] Embodiments of the present invention are expected to increase the efficiency of cooling a stack whose heat comes from the incident electron beam power and from the power consumed by, for example, the electronic devices in the detector 240. By reducing the distance between the heat source and the heat sink (i.e., the heat regulating channel 80), the cooling may be made more efficient. By providing an electrically insulating material 83, the risk of discharge can be prevented from increasing. For example, in one embodiment, portions of the electron optical module 41 can be operated at high voltage. For example, high voltage can be applied to one or more of the planar elements 61 to 64. In contrast, the heat regulating channel 80 and / or the heat regulating fluid within the heat regulating channel 80 can be at a reference ground potential of the electron optical module 41.

[0114] Figure 8 yes Figure 7 Schematic plan view of the electronic optical module 41 shown. Figure 8 As shown, in one embodiment, material 83 surrounds one or more of planar elements 61 to 64. For example, when viewed in a direction parallel to the beam path, material 83 may surround planar element 61. Material 83 may surround one or more of planar elements 61 to 64 in the plane of planar elements 61 to 64.

[0115] exist Figure 8 In FIG. 6 , the most upstream planar element 61 of the beam is shown. This is because Figure 8 The view is viewed from the beam upstream side of the electron optical module 41. Figure 8A material 83 is shown surrounding the bundle-most upstream planar element 61 in the plane of the bundle-most upstream planar element 61. In one embodiment, the material 83 similarly surrounds the other planar elements 62 to 64. The material 83 is configured to reduce the likelihood of electrical breakdown between the planar elements 61 to 64 and the thermal regulation channel 80. The material 83 is configured to electrically insulate the planar elements 61 to 64 from each other. The material 83 is configured to reduce the likelihood of electrical breakdown between the planar elements 61 to 64. The material 83 extends the creep path between the planar elements 61 to 64. In one embodiment, the outwardly facing surfaces of the planar elements 61 to 64 are covered with the material 83. By covering the outwardly facing surfaces of the planar elements 61 to 64, the creep path between the planar elements 61 to 64 can be extended.

[0116] In one embodiment, the material 83 continuously fills the volume between one or more planar elements 61 to 64 and the thermal regulation channel 80. The continuous filling of the material 83 means that there are generally no gaps or pockets that are not filled by the material 83. Specifically, there is no path from the planar elements 61 to 64 to the thermal regulation channel 80 that does not pass through the material 83. That is, any path (such as a virtual straight line) between the planar elements 61 to 64 and the thermal regulation channel passes through the material 83. The material 83 separates the thermal regulation channel 80 from the planar elements 61 to 64. In one embodiment, the material 83 completely fills the volume between the planar elements 61 to 64 and the thermal regulation channel 80. Figure 8 The material 83 filling the volume between the most upstream planar element 61 of the bundle and the heat regulating channel 80 is shown. In one embodiment, the material 83 is similarly continuously filled, and ideally, the volume between all planar elements 61 to 64 and the heat regulating channel 80 is completely filled. Alternatively, the material 83 can fill the volume between a subset of the planar elements 61 to 64 and the heat regulating channel 80. In one embodiment, the planar elements in the planar elements 61 to 64 are configured to operate at a voltage similar to the heat regulating channel 80 (e.g., ground potential), so that it is not necessary to provide material 83 between the planar elements and the heat regulating channel 80. In an arrangement where a heat conducting plate is located in the middle of a stack or there are multiple heat conducting plates in a stack, there may be multiple volumes between the planar elements 61 to 64 and the heat regulating channel. One or more of the multiple volumes can be filled with material 83. The filling of multiple volumes can be similar to the filling described for one volume (e.g., gap 82) as described herein.

[0117] In one embodiment, the volume filled by material 83 has a surface defined by a portion of a surface of a thermally conductive plate (e.g., detector 240 or detector spacer 75). The surface of the thermally conductive plate may be parallel to one or more planar elements 61 to 64. For example, in Figure 7In the arrangement shown, the volume filled by material 83 is defined by the portion of the beam upstream surface of the spacer 74 located between the planar elements 63, 64. The spacer 74 can form a thermally conductive plate. The spacer 74 can include the same material as the other spacers 71. Compared with the other spacers 71 to 73, the detector spacer 75 can extend laterally away from the position of the electron beam passing through the module 41, although this need not be the case. This may be ideal for assisting the conduction of heat loads away from the detector and limiting the conduction of heat to the stack. The detector spacer 75 can extend laterally inward to a position similar to the other spacers 71, 72, 73, 74 in the stack. The spacer can extend laterally so far that it contacts the thermal regulation channel 80, for example, contacting the downward facing surface or the upward facing surface of the thermal regulation channel 80.

[0118] In one embodiment, the volume filled by the material 83 is defined by the surface of the heat regulating channel 80. The surface of the heat regulating channel 80 may face one or more of the planar elements 61 to 64. For example, Figure 7 As shown, in one embodiment, the heat regulating channel 80 has a surface facing upstream of the beam, a surface facing downstream of the beam, an outward-facing surface, and an inward-facing surface. The inward-facing surface faces the planar elements 62, 63. The inward-facing surface of the heat regulating channel 80 defines a volume filled with material 83.

[0119] In one embodiment, the volume filled by material 83 is defined by the outer surface of one or more planar elements 61 to 64. For example, Figure 6 As shown, in one embodiment, the outer surface of the planar elements 61, 62, 63 defines a volume filled by material 83. In one embodiment, the planar elements 61 to 64 include one or more apertures defined therein. The aperture can be provided for one or more electron beams to pass therethrough. The aperture is in the region through which the electron beam passes (i.e., the central portion of the planar elements 61 to 64). The outer surface of the planar elements 61 to 64 can be defined relative to the aperture defined in the planar elements 61 to 64. The outer surface faces away from the aperture.

[0120] like Figure 7 As shown, in one embodiment, the volume filled by the material 83 is defined by one or more spacers 71 to 74. For example, in Figure 7In the arrangement shown, the volume is defined by the spacers 72, 73 between adjacent planar elements 61 to 63. More specifically, the volume is defined by the outer surfaces of the spacers 72, 73 between adjacent planar elements 61 to 63. In one embodiment, the volume is defined by one or more spacers 74 between individual planar elements 63 and the thermally conductive plate. For example, the upstream surfaces of the spacers 74 located between the planar elements 63 and the thermally conductive plate define the volume. In one embodiment, the volume filled by the material 83 is defined by one or more spacers 71 upstream of the bundle of planar elements 61 to 64. For example, as Figure 7 As shown, the outer surface of the beam-most upstream spacer 71 (which is located upstream of the beam-most upstream planar element 61 of the electron optical module 41) defines a volume filled with material 83. In one embodiment, material 83 includes glass, such as borosilicate glass. In one embodiment, material 83 includes the same substance as one or more of the spacers 71 to 75.

[0121] During use of the electronic optical module, one or more of the planar elements 61 to 64 may have a voltage applied to them. In one embodiment, one or more of the planar elements 61 to 64 are connected to a high voltage power supply. High voltage refers to a voltage of at least 2 kV, optionally at least 5 kV, optionally at least 10 kV, optionally at least 20 kV relative to a reference ground potential. The planar element may be connected to the high voltage power supply via a cable and an electrical connector. For example, Figure 8 Schematically shown are two cables 85 and two electrical connectors 84. Each cable 85 and electrical connector 84 may correspond to a respective planar element. The electro-optical device or at least the electro-optical arrangement may include one or more voltage sources to supply a respective potential difference to the stacked components (e.g., one or more of the stacked planar elements).

[0122] Fig. 9 Yes Figure 8 Schematic diagram of the electron optical module 41 is shown, but with the beam most upstream spacer 71 and the beam most upstream planar element 61 removed. Fig. 9 In the view shown, some of the potting material 83 surrounding the bundle's most upstream spacer 71 and the bundle's most upstream planar element 61 has been removed. Fig. 9 The next bundle most upstream spacer 72 and the next bundle most upstream planar element 62 are shown. The electrical connector 84 is at Fig. 9 In other words, Fig. 9 can be considered to pass through the next bundle at the most upstream spacer 72 Figure 8 A cross section of the electron-optical module 41 is shown.

[0123] exist Fig. 9In the arrangement shown, the electrical connector 84 shown on the right side of the drawing can be connected to the planar element 62 shown in the drawing. The electrical connector 84 is configured to electrically connect the planar element 62 to the cable 85 on the right side of the drawing. The electrical connector 84 and the cable 85 are configured to electrically connect the planar element 62 to a high voltage power supply. The electrical connector 84 and the cable 85 shown on the left side of the drawing can be configured to connect another planar element (e.g., the planar element 63) in the planar elements to the high voltage power supply.

[0124] Despite Figure 8 and Fig. 9 Two electrical connectors 84 and corresponding cables 85 are shown, but in one embodiment, the electronic optical module 41 includes one electrical connector 84 with an associated cable 85, or has three or more electrical connectors associated with cables. In one embodiment, a different electrical connector and cable are provided for each planar element. Alternatively, two or more planar elements can be connected to the same cable and power supply.

[0125] exist Figure 8 In the view shown, the upstream surface of the electrical connector 84 is covered by material 83. For example, Figure 8 As shown, in one embodiment, material 83 electrically isolates thermal regulation channel 80 from one or more electrical connectors 84. Material 83 reduces the likelihood of electrical breakdown between electrical connector 84 (which may include a conductive material, such as metal) and thermal regulation channel 80. In one embodiment, material 83 reduces the likelihood of electrical breakdown between electrical connector 84 and planar elements 61-64.

[0126] Material 83 is an electrically insulating material. In one embodiment, material 83 is also thermally conductive. When the thermal conductivity of material 83 is good, material 83 can help increase the heat flow from planar elements 61 to 64 toward thermal regulation channel 80. In one embodiment, material 83 is selected from the group consisting of: ceramics, glass such as borosilicate glass, epoxy resin, and insulating adhesive.

[0127] By providing material 83 between the planar elements 61 to 64 and the heat regulating channel 80, the distance between the planar elements 61 to 64 and the heat regulating channel 80 can be reduced. In one embodiment, the distance between the planar elements 61 to 64 and the heat regulating channel 80 is less than the distance between the edge of the planar elements 61 to 64 and the center of the beam path. Figure 8 or Fig. 9In the view shown (i.e., parallel to the beam path), the shortest distance from the edge of the planar element (which corresponds to the edge of the spacers 71, 72) to the thermal regulation channel 80 (which corresponds to the position of the electrical insulator 81) is less than the distance from the edge of the planar element to the center of the beam path (which corresponds to the center of the planar element). The shorter distance between the planar element and the thermal regulation channel 80 helps to increase the heat flow toward the heat sink (i.e., the thermal regulation channel 80). This helps to control the temperature of the electron optical module 41. The center of the beam path can correspond to the center of the aperture in the planar element through which the electron beam passes. When the planar element includes an aperture array (or aperture grid), the center of the beam path corresponds to the center of the aperture grid. The shorter distance can enable the electron optical module 41 to be more compact than otherwise. Considering the volume constraints in the design of charged particle devices such as evaluation devices, a more compact electron optical module 41 is easier to use.

[0128] In one embodiment, the distance between the planar element and the thermal regulation channel 80 is less than the width of the thermal regulation channel 80 when viewed in a direction parallel to the beam path. Figure 8 and Fig. 9 In the view shown (note that Figure 8 and Fig. 9 The width of the heat regulating channel 80 corresponds to the width of the electrical insulator 81. The shortest distance between the edge of the spacer 71 and the electrical insulator 81 is less than the width of the electrical insulator 81 (i.e., the dimension in the up-down direction in the drawing, which is parallel to the direction of the plane of the planar elements 61 to 64).

[0129] like Figures 6 to 9 As shown, in one embodiment, the surface of the thermal regulation channel 80 facing the direction parallel to the beam path is covered with an electrical insulator 81. In one embodiment, the electrical insulator 81 comprises a material selected from the group consisting of: ceramic and glass such as borosilicate glass.

[0130] exist Figure 6 and Figure 7 In FIG. 8 , the surfaces of the heat regulating channel 80 that face in the direction parallel to the beam path are the upper and lower surfaces in the orientation shown in the drawings. Figure 6 and Figure 7As shown, the upper surface of the thermal regulation channel 80 (i.e., the beam upstream surface) is covered with an electrical insulator 81. The electrical insulator 81 is configured to electrically insulate the thermal regulation channel 80 from other components of the electron optical device. For example, the electrical insulator 81 is configured to reduce the possibility of electrical breakdown between the thermal regulation channel 80 and one or more of the planar elements 61 to 64. The electrical insulator 81 can form an insulating block. The electrical insulator 81 extends the creep path between the thermal regulation channel 80 and the open portion of the stack (e.g., the central area of ​​the beam upstream planar element 61 that is not covered by the beam upstream spacer 71).

[0131] In one embodiment, the outwardly facing surface of the thermal regulation channel 80 is covered with an electrical insulator. Figure 6 and Figure 7 In the orientation shown, the outwardly facing surface of the thermal regulating channel 80 is the surface facing away from the planar elements 61 to 64. For example, the outwardly facing surface of the thermal regulating channel 80 on the left side of the figure is the left side surface of the thermal regulating channel 80. By covering the outwardly facing (relative to the beam path) surface of the thermal regulating channel 80, the creep path between the thermal regulating channel 80 and the open portion of the stack can be extended.

[0132] like Figure 8 As shown, in one embodiment, material 83 completely surrounds the stack of planar elements and spacers that operate at high voltage during use of the electron optical module 41. Material 83 fills the gap 82 between the thermal regulation channel 80 and the stack. Material 83 helps to reduce the enhancement of the local electric field in the possible vacuum gap. The use of material 83 is synergistically combined with the provision of the thermal regulation channel 80 and the thermal conductive plate. Specifically, material 83 allows the thermal regulation channel 80 to be closer to the stack, so that heat is transferred a shorter distance toward the thermal regulation channel 80 through the thermal conductive plate.

[0133] In one embodiment, the thermally conductive plate is monolithic. For example, the detector 240 can be monolithic. The detector spacer 75 can be monolithic. The beam downstream spacer 74 between the planar element 63 and the planar element 64 can be monolithic. When the thermally conductive plate is monolithic, the thermally conductive plate can better transfer heat toward the thermal regulation channel 80. In one embodiment, the thermally conductive plate includes a planar element, such as the detector 240.

[0134] In one embodiment, the detector 240 is secured to the thermally conductive plate. For example, the detector spacer 75 may constitute the thermally conductive plate. The detector 240 is secured to the detector spacer 75. In one embodiment, the detector 240 is included within the thermally conductive plate. For example, in one embodiment, the thermally conductive plate is comprised of the detector 240 and the detector spacer 75. In one embodiment, the thermally conductive plate is comprised of the detector 240. The detector spacer 75 may be separate from the thermally conductive plate. The detector spacer 75 may be omitted. Alternatively, the detector spacer 75 may be integral with the detector 240, the detector spacer 75 being formed of an electrically isolating and thermally conductive material similar to the detector 240.

[0135] like Figure 6 and Figure 7 As shown, in one embodiment, the thermal regulation channel 80 is fixed to the detector 240 via the detector spacer 75. The detector spacer 75 is located between the thermal regulation channel 80 and the detector 240. Heat is transferred from the detector 240 to the thermal regulation channel 80 via the detector spacer 75. In an alternative arrangement, the thermal regulation channel 80 can be in direct contact with the detector 240. The detector spacer 75 can be omitted (e.g., integrated into the detector), or the detector spacer 75 can have an outer edge that is internal to the thermal regulation channel 80.

[0136] In one embodiment, the thermally conductive plate is a planar element that includes an array of apertures for one or more electron beams to pass through along a beam path. For example, in one embodiment, the thermally conductive plate is a detector 240. Detector 240 may include one or more apertures for electron beams (e.g., different beams of a beam grid) to pass through. In an alternative embodiment, the thermally conductive plate is connected to a planar element that includes an array of apertures for one or more electron beams to pass through along a beam path. For example, in one embodiment, the thermally conductive plate is a detector spacer 75 or a spacer 74, wherein each spacer is connected to a planar element (e.g., detector 240 or planar elements 63, 64) that includes one or more apertures.

[0137] In one embodiment, the thickness of the planar element connected to the thermally conductive plate in a direction parallel to the beam path is greater than or substantially equal to the thickness of the other planar element. In one embodiment, at least one of the planar elements is connected to the thermally conductive plate. The individual planar elements connected to the thermally conductive plate are fixed to the thermally conductive plate. When there are multiple thermally conductive plates, at least one of the planar elements can be conducted to each thermally conductive plate.

[0138] In one embodiment, the thermally conductive plate can be, for example, an individual beam corrector plate or deflector plate, or can be connected to an individual beam corrector plate or deflector plate. For example, in one embodiment, the planar element constituting or connected to the thermally conductive plate includes a plurality of electrodes configured to apply an electric field for aberration correction and / or deflection to one or more beam paths. The electrodes are arranged relative to corresponding apertures of the aperture array. In one embodiment, the electrodes of the aperture operate on one or a group of the beam paths. In one embodiment, one or more electrodes operate on a beam path independent of other beam paths.

[0139] In one embodiment, the planar element constituting or connected to the thermally conductive plate is a multipole array. The multipole array is used to operate on electrons. For example, the multipole array may include individual beam deflectors, stigmators, or may have another function of a corrector. In one embodiment, the planar element includes a plurality of individual deflectors configured to deflect the electron beams at the respective apertures independently of each other.

[0140] As mentioned above, in one embodiment, the electron optical module 41 includes electronic circuitry, for example, in a circuitry layer. The electronic circuitry can be included in a thermally conductive plate, for example, in the detector 240, for example, as a CMOS structure. In one embodiment, the electronic circuitry has a higher density closer to the thermal regulation channel 80 than in the center of the beam path. For example, Figure 6 and Figure 7 As shown, in one embodiment, the electronic circuitry is primarily located in a peripheral region 247 of the detector 240. As mentioned above, in one embodiment, the electronic component comprises an ADC. Additionally or alternatively, the electronic component comprises a transimpedance amplifier (TIA).

[0141] In one embodiment, the electronic optical module 41 includes another heat conducting plate. For example, in one embodiment, the other heat conducting plate extends between the planar elements 61 to 64 and the heat regulating channel 80. In one embodiment, the heat regulating channel 80 contacts both the heat conducting plate and the other heat conducting plate. In one embodiment, the heat regulating channel 80 is located between the two heat conducting plates. By providing another heat conducting plate, heat conduction toward the heat regulating channel 80 can be improved. This helps to control the temperature of the electronic optical module 41.

[0142] In one embodiment, multiple thermally conductive plates are configured to transfer heat to the same thermal regulation channel 80. This can improve heat transfer to the heat sink without requiring multiple thermal regulation channels to cool different planar components.

[0143] As mentioned above, in one embodiment, the electron optical module 41 is or includes an objective lens assembly, which includes an objective lens array 241. The objective lens 241 is used to focus the electron beam on the sample position. Alternatively, the electron optical module 41 can be a converging lens assembly, which is used to generate multiple electron beams from a source beam and / or focus the electron beam at an intermediate focal plane. In one embodiment, the electron optical module 41 is field replaceable. Alternatively, the electron optical module 41 can include, for example, a lens array for being located in different positions in the beam path, such as a converging lens array or an objective lens array, such as between two giant lenses, such as a converging lens and an objective lens, one of which can be a magnetic lens. The electron optical module 41 can be removed from the electron optical device and / or the electron optical module 41 can be inserted into the electron optical device without additionally disassembling the electron optical device.

[0144] In one embodiment, the electronic optical module 41 may be included in, for example, Figure 2 or Figure 3 or Figure 5 In the electron optical device 40 shown. In one embodiment, the planar elements 61 to 64 of the electron optical module 41 include a beam stop array. The beam stop array can be downstream of another planar element (such as a deflector array). The deflector array can be included in the same electron optical module as the beam stop array. In one embodiment, the beam stop array includes an array of apertures for the beam path to pass through. Individual deflectors of the deflector array can be configured to controllably operate on individual electron beams or groups of electron beams to be blocked by the beam stop array or to be directed through individual apertures.

[0145] The present invention can be embodied as a method for regulating the temperature of one or more components of an electron optical module 41. In one embodiment, the method includes: arranging a plurality of planar elements 61 to 64 at various locations on a beam path to operate on electrons. For example, the electron optical module 41 can be installed in an electron optical device 41 of an electron optical apparatus 100.

[0146] In one embodiment, the method includes separating the heat regulating channel 80 from the planar elements 61 to 64 in a direction passing through the plurality of planar elements 61 to 64. Heat is transferred to the heat regulating channel 80 through the heat conducting plate toward the heat regulating channel 80. In one embodiment, the heat conducting plate extends between the planar elements 61 to 64 and the heat regulating channel 80 in a direction parallel to one or more of the planar elements 61 to 64. For example, the heat conducting plate may be as Figure 6 and Figure 7 The detector 240 shown may include Figure 6 and Figure 7 Detector 240 is shown.

[0147] In one embodiment, the present invention is embodied as a method for regulating the temperature of one or more components of an electron optical module 41. In one embodiment, the method includes: operating an electron optical device 100 to project electrons to a sample location. In one embodiment, the method includes: flowing a thermal regulation fluid through a thermal regulation channel 80 and transferring heat toward the thermal regulation channel 80 through a thermally conductive plate.

[0148] The electron optical module 41 may include or be a lens assembly for manipulating the electron beam wave. The lens assembly may be, for example, an objective lens assembly or a converging lens assembly, or may be a part of an objective lens assembly or a converging lens assembly. A lens assembly such as an objective lens assembly may also include an additional lens array, such as a control lens array 250, which includes at least two plates.

[0149] In one embodiment, at least one of the planar elements 61 to 64, 240 comprises a micro-electromechanical element. In one embodiment, the electron-optical module 41 comprises one or more electron-optical elements, which include elements that can be referred to as micro-electromechanical components (although such components may not include moving features or movable features), or can be made using a technology suitable for making micro-electromechanical components (e.g., 'MEMS technology'), some of which are designed to have electron-optical functions. The electron-optical module 41 or at least a part of the electron-optical module 41 can be manufactured by such a technology. The electron-optical module 41 can include one or more elements that can be considered as MEMS elements. During use, one or more of such elements can be controlled to be set at a high potential difference relative to a reference potential (e.g., ground). Such elements may need to be precisely positioned (e.g., aligned) within the electron-optical module 41, such as relative to the path of the beam grid and relative to other electron-optical elements within the device (e.g., relative to the source, relative to the path of the sample and / or the beam grid). It is contemplated that embodiments of the present invention allow for more precise positioning (e.g., alignment) of such elements within a stack of such electron-optical modules 41, such as during operation, without deforming the electron-optical modules 41, such as due to externally applied forces or moments. Additionally or alternatively, embodiments of the present invention may enable more precise positioning, e.g., alignment, of such elements relative to other elements in the electron-optical device 40, and thus enable more precise positioning, e.g., alignment, of a stack of electron-optical modules 41 including such elements within the electron-optical device 40.

[0150] As mentioned above, in one embodiment, the electron optical module 41 is an electron optical lens assembly. The electron optical lens assembly may include an objective lens assembly. The electron optical lens assembly may be an objective lens assembly. In an alternative embodiment, the electron optical lens assembly is an electron optical converging lens assembly.

[0151] In one embodiment, the electron optical module 41 includes a collimator. For example, in one embodiment, the electron optical module 41 includes a magnetic collimator combined with an electrostatic focusing lens array. The electron optical module 41 may include a single aperture lens array with one or two giant electrodes, which is placed away from the virtual source conjugate plane.

[0152] In an alternative embodiment, the electron optical module 41 includes a magnetic giant lens combined with an electrostatic slit deflector. The magnetic giant lens can be used for collimation. As another alternative, in one embodiment, the electron optical module 41 includes a combined magnetic and electrostatic giant lens and a beam downstream slit deflector.

[0153] In general, the electron optical module 41 can include any boards, such as a board of detector arrays, a board of lens electrodes (multiple deflectors can be integrated into the board), multiple deflector arrays, beam aperture arrays (e.g., an upper beam aperture array and / or a final beam limiting array), deflector arrays (e.g., a strip deflector array), and other types of corrector elements.

[0154] The embodiments described in this document mainly focus on a multi-beam electron-optical device 40. The invention is equally applicable to a single-beam electron-optical device 40.

[0155] The plurality of electron-optical devices may be comprised in an electron-optical device array.The electron-optical devices of the electron-optical device array are preferably configured to focus respective multiple beams simultaneously onto different areas of the same sample.

[0156] Although the present invention has been described in conjunction with various embodiments, other embodiments of the present invention may occur to those skilled in the art after considering this specification and practicing the invention disclosed herein. For example, as described above, in one embodiment, the electronic optical module 41 includes planar elements 61 to 64, thermal regulation channels 80, and material 83. However, the planar elements 61 to 64, thermal regulation channels 80, and / or materials 83 of the present invention may be used anywhere in the electronic optical device 40 where there may be heating and / or electrical breakdown issues that may be undesirable. In one embodiment, the electronic optical device 40 includes planar elements 61 to 64, thermal regulation channels 80, and material 83 separated from the electronic optical module 41. The description and embodiments are to be considered exemplary only, with the true scope and spirit of the present invention being indicated by the appended claims.

[0157] The above description is intended to be illustrative and not limiting. Therefore, it will be apparent to those skilled in the art that modifications may be made as described without departing from the scope of the claims and clauses set forth below.

[0158] The following terms are provided:

[0159] Item 1. A charged particle optical module for guiding charged particles along a charged particle path toward a sample position, the charged particle optical module comprising a plurality of planar elements arranged across the beam path and configured to operate on the charged particles; a thermal regulation channel separated from the planar elements in a direction passing through the plurality of elements; and a thermal conductive plate connected to the thermal regulation channel for transferring heat toward the thermal regulation channel; wherein the thermal conductive plate extends between the planar elements and the thermal regulation channel in a direction parallel to one or more of the planar elements, wherein the module comprises one or more electrostatic elements, and ideally, comprises only electrostatic elements.

[0160] Item 2. A charged particle optical module according to Item 1, comprising material that electrically isolates the planar elements from the thermal regulation channel, ideally, one or more of the planar elements comprises an electrostatic optical element, ideally, one or more of the planar elements may be an electrostatic optical element, ideally, one or more of the planar elements may respectively comprise one or more electrodes for manipulating the beam path, for example, one or more of the planar elements may respectively be individual planar electrodes, ideally, one or more of the planar elements (if not all) are defined as multiple apertures for corresponding beams, and ideally, one or more of the planar elements are corresponding plates.

[0161] Clause 3. The charged particle optics module of Clause 2, wherein the material surrounds one or more of the planar elements.

[0162] Item 4. A charged particle optical module according to Item 2 or 3, wherein the material continuously fills, ideally completely fills, the volume between one or more planar elements and the thermal regulation channel, ideally the volume between all planar elements and the thermal regulation channel, and ideally the volume has a surface defined by at least one of the following: a portion of the surface of the thermally conductive plate, a portion of the surface of the thermally conductive plate ideally parallel to one or more of the planar elements; a surface of the channel, a surface of the channel ideally facing one or more of the planar elements; an outer surface of one or more planar elements; and one or more spacers, the one or more spacers being located between adjacent planar elements and / or between individual planar elements and the thermally conductive plate.

[0163] Clause 5. A charged particle optics module according to any of clauses 2 to 4, wherein the material electrically isolates the thermal regulation channel from one or more electrical connectors for electrically connecting one or more of the planar elements to an electrical cable.

[0164] Clause 6. The charged particle optics module of any of Clauses 2 to 5, wherein the material is selected from the group consisting of: ceramics, glass such as borosilicate glass, epoxy resin, and insulating adhesive.

[0165] Clause 7. A charged particle optics module according to any preceding clause, wherein the distance between the planar element and the thermal regulation channel is smaller than the distance between an edge of the planar element and the centre of the beam path.

[0166] Clause 8. A charged particle optics module according to any preceding clause, wherein a distance between the planar element and the thermal regulation channel when viewed in a direction parallel to the beam path is less than a width of the thermal regulation channel.

[0167] Clause 9. A charged particle optical module according to any preceding clause, wherein a surface of the thermal regulation channel facing in a direction parallel to the beam path is covered with an electrical insulator.

[0168] Clause 10. A charged particle optics module according to any preceding clause, wherein a surface of the thermal regulation channel facing away from the beam path is covered with an electrical insulator.

[0169] Clause 11. A charged particle optics module according to any preceding clause, wherein the thermally conductive plate is monolithic, and ideally comprises a planar element.

[0170] Clause 12. A charged particle optics module according to any preceding clause, wherein the thermally conductive plate is a planar element or is connected to a planar element, such as a detector for detecting charged particles (eg, signal particles from the sample location).

[0171] Item 13. A charged particle optical module according to Item 12, wherein the thickness of the detector in a direction parallel to the beam path is greater than or substantially equal to the thickness of one or more of the planar elements, and ideally, the detector is configured to conduct heat generated in the detector during operation toward the thermal regulation channel, and ideally, the thickness is sized and / or the detector includes a material having a thermal conductivity sufficient to conduct heat generated in the detector during operation toward the thermal regulation channel.

[0172] Clause 14. A charged particle optics module according to clause 12 or 13, wherein the detector is fixed to the thermally conductive plate, ideally the detector is included in the thermally conductive plate, ideally the thermally conductive plate consists of the detector.

[0173] Clause 15. A charged particle optics module according to any preceding clause, wherein the thermally conductive plate is or is connected to a planar element comprising an array of apertures through which one or more beam paths pass.

[0174] Clause 16. The charged particle optical module of Clause 15, wherein a thickness of the planar element in a direction parallel to the beam path is greater than or substantially equal to a thickness of another of the planar elements.

[0175] Clause 17. A charged particle optics module according to clause 15 or 16, wherein the planar element is fixed to a thermally conductive plate.

[0176] Clause 18. A charged particle optical module according to any one of clauses 15 to 17, wherein the planar element comprises a plurality of electrodes configured to apply aberration correction to one or more of the beam paths, the electrodes being arranged relative to corresponding apertures of the aperture array, ideally the electrodes of the apertures operating on one or a group of the beam paths, and ideally one or more electrodes operating on a beam path independent of other beam paths.

[0177] Clause 19. A charged particle optical module according to any one of clauses 15 to 18, wherein the planar element is a multipole array for operating the charged particles, such as other functions of individual beam deflectors, stigmators or correctors, the multipole array comprising a plurality of individual deflectors configured to deflect the charged particle beams independently of each other at corresponding apertures.

[0178] Clause 20. A charged particle optical module according to any of the preceding clauses, wherein at least one of the planar elements is a beam limiting aperture array, which is configured to shape one or more beams of charged particles, and ideally, is configured to generate one or more charged particle beams.

[0179] Item 21. A charged particle optical module according to any of the preceding items, comprising an electronic circuit system, ideally in the circuit system layer, ideally in the thermal conductive plate and / or detector, ideally the electronic circuit system has a higher density at a position closer to the thermal regulation channel than the center of the beam path, and ideally multiple electronic components are positioned closer to the thermal regulation channel than the center of the beam path.

[0180] Clause 22. The charged-particle optics module of Clause 21, wherein the electronic components comprise an analog-to-digital converter and / or a transimpedance amplifier.

[0181] Clause 23. A charged particle optics module according to any preceding clause, wherein the thermally conductive plate comprises a CMOS device or is connected to a component comprising a CMOS device.

[0182] Item 24. A charged particle optical module according to any of the preceding items, comprising a plurality of thermal regulation channels, wherein the plurality of thermal regulation channels extend along different sides of the planar element, and ideally, two or more of the plurality of thermal regulation channels are separated, and ideally, two or more of the plurality of thermal regulation channels are ideally connected in parallel and / or in series.

[0183] Clause 25. The charged particle optical module of any preceding clause, wherein the one or more thermal regulation channels extend around the charged particle optical module.

[0184] Clause 26. The charged particle optical module according to clause 25, wherein the one or more thermal regulation channels extend more than once, ideally multiple times, ideally in a spiral manner around the charged particle optical module.

[0185] Clause 27. A charged particle optical module according to any preceding clause, comprising a further thermally conductive plate, ideally extending between the planar element and the thermal regulation channel, ideally the thermal regulation channel being in contact with the thermally conductive plate and the further thermally conductive plate between the two thermally conductive plates.

[0186] Clause 28. A charged particle optical module according to any preceding clause, comprising one or more spacer elements between two adjacent planar elements of the plurality of planar elements, individual spacer elements being configured to support and / or electrically isolate the adjacent planar elements, and ideally, an outer surface of the spacer element partially defines the surface of the volume between the plurality of planar elements.

[0187] Clause 29. A charged-particle optics module according to any preceding clause, wherein at least one of the planar elements comprises a micro-electromechanical component.

[0188] Item 30. A charged particle optical module according to any of the preceding items, wherein the charged particle optical module is or includes: an objective lens assembly, the objective lens assembly comprising an objective lens array for focusing the charged particle beam onto the sample position; or a converging lens assembly for generating multiple charged particle beams from a source beam and / or focusing the multiple beams at an intermediate focal plane.

[0189] Clause 31. A charged particle optical device for directing charged particles towards a sample location, the charged particle optical device comprising a charged particle optical module according to any preceding clause.

[0190] Clause 32. A charged particle optical device according to clause 31, wherein the planar element comprises a beam stop array, ideally located downstream of the beam of another planar element, the other planar element being a deflector array, wherein the deflector array can be included in the same charged particle optical module as the beam stop array, the beam stop array comprising an array of apertures through which the beam path passes, wherein individual deflectors of the deflector array are configured to controllably operate on individual beams or groups of beams to be blocked by the beam stop array or to be directed through individual apertures.

[0191] Clause 33. A charged particle optical device comprising the charged particle optical module according to any one of clauses 1 to 30 or the charged particle optical apparatus according to clause 31 or 32.

[0192] Clause 34. The charged particle optical apparatus of clause 33, further comprising an actuatable stage for supporting a sample at the sample position.

[0193] Item 35. A method for regulating the temperature of one or more components of a charged particle optical module, which is used to guide charged particles along a beam path toward a sample position, the method comprising: arranging a plurality of planar elements across the beam path to operate on the charged particles, for example, installing the module into a charged particle optical device of a charged particle optical apparatus; separating a thermal regulation channel from the planar elements in a direction passing through the plurality of elements; and transferring heat toward the thermal regulation channel via a thermal conductive plate connected to the thermal regulation channel; wherein the thermal conductive plate extends between the planar elements and the thermal regulation channel in a direction parallel to one or more of the planar elements.

[0194] Item 36. A method for regulating the temperature of one or more components of a charged particle optical module, which is used in a charged particle optical device to guide charged particles along a beam path toward a sample position, the charged particle optical module comprising a plurality of planar elements configured to operate on the charged particles; a thermal regulation channel separated from the plurality of planar elements; and a thermally conductive plate extending between and in thermal contact with the plurality of planar elements and the thermal regulation channel, the method comprising: operating the charged particle optical device to project charged particles to a sample position; flowing a thermal regulation fluid through the thermal regulation channel; and transferring heat toward the thermal regulation channel through the thermally conductive plate.

Claims

1. A charged particle optical module for guiding charged particles along a charged particle path toward a sample location, the charged particle optical module comprising: a plurality of planar elements arranged across the beam path and configured to operate on the charged particles; a heat regulating passage spaced apart from the planar element in a direction passing through the plurality of elements; as well as a heat conducting plate connected to the heat regulating channel for transferring heat toward the heat regulating channel; Wherein the thermally conductive plate extends between the planar element and the thermal regulating channel in a direction parallel to one or more of the planar elements.

2. The charged particle optical module of claim 1, comprising a material electrically isolating the planar element from the thermal regulation channel.

3. A charged particle optical module according to claim 2, wherein the material surrounds one or more of the planar elements.

4. A charged particle optical module according to claim 2 or 3, wherein the material continuously fills, ideally completely fills, one or more planar elements, ideally the volume between all planar elements and the thermal regulation channel, ideally the volume having a surface defined by at least one of the following: a. a portion of the surface of the heat conducting plate, ideally, a portion of the surface of the heat conducting plate parallel to one or more of the planar elements; b. a surface of the channel, ideally, the surface of the channel facing one or more of the planar elements; c. the outer surface of one or more planar elements; as well as d. one or more spacers, i. Located between adjacent planar elements; and / or ii. Located between individual planar elements and the thermally conductive plate.

5. A charged particle optical module according to any preceding claim, wherein the distance between the planar element and the thermal regulation channel is less than the distance between the edge of the planar element and the center of the beam path, and / or wherein the distance between the planar element and the thermal regulation channel is less than the width of the thermal regulation channel when viewed in a direction parallel to the beam path.

6. A charged particle optical module according to any preceding claim, wherein a surface of the thermal regulation channel facing in a direction parallel to the beam path is covered with an electrical insulator and / or wherein a surface of the thermal regulation channel facing away from the beam path is covered with an electrical insulator.

7. A charged particle optical module according to any preceding claim, wherein the thermally conductive plate is monolithic, ideally comprising a planar element, and / or wherein the thermally conductive plate is a planar element or is connected to a planar element, such as a detector for detecting signal particles from the sample position.

8. A charged particle optical module according to claim 7, wherein the detector is fixed to the thermally conductive plate, ideally the detector is included in the thermally conductive plate, ideally the thermally conductive plate consists of the detector.

9. A charged particle optics module according to any preceding claim, wherein the thermally conductive plate is a planar element or is connected to a planar element, the planar element comprising: An array of apertures through which one or more beam paths pass.

10. A charged particle optical module according to claim 9, wherein the planar element comprises a plurality of electrodes configured to apply an aberration correction to one or more of the beam paths, the electrodes being arranged relative to respective apertures of the aperture array.

11. A charged particle optical module according to any preceding claim, wherein at least one of the planar elements is a beam limiting aperture array configured to shape one or more beams of charged particles.

12. A charged particle optics module according to any preceding claim, comprising electronic circuitry, ideally in a circuitry layer, in the thermally conductive plate and / or in the detector.

13. A charged particle optics module according to any preceding claim, comprising a plurality of thermal regulation channels extending along different sides of the planar element.

14. A charged particle optics module according to any preceding claim, comprising one or more spacer elements between two adjacent planar elements of the plurality of planar elements, individual spacer elements being configured to support and / or electrically isolate the adjacent planar elements.

15. A charged particle optical device for directing charged particles towards a sample location, the charged particle optical device comprising a charged particle optical module according to any preceding claim.

Images