Charged-particle optical apparatus

Abstract

A charged particle optical device configured to project a charged particle multi-beam, the device comprising: a charged particle device switchable between: (i) an operational configuration in which the device is configured to project the multi-beam onto the sample along an operational beam path extending from a source of the multi-beam to the sample; and (ii) a monitoring configuration in which the device is configured to project the multi-beam onto the detector along a monitoring beam path extending from the source to the detector; wherein the monitoring beam path deviates from the operational beam path midway through the operational beam path.

Description

Technical Field

[0001] The embodiments provided herein are generally related to charged particle optical devices and projection methods, and more specifically to charged particle optical devices and projection methods using multiple charged particle sub-beams. Prior Technology

[0002] In the manufacture of semiconductor integrated circuit (IC) wafers, improper patterning defects often occur on the substrate (i.e., wafer) or mask during the manufacturing process, thereby reducing yield. These defects can arise due to, for example, optical effects and accompanying particles, as well as in subsequent processing steps such as etching, deposition, or chemical mechanical polishing. Therefore, monitoring the extent of improper patterning defects is a critical process in IC wafer manufacturing. More generally, the inspection and / or measurement of the surface of substrates or other objects / materials is an important process during and / or after their manufacturing.

[0003] Pattern inspection tools with charged particle beams have been used to inspect objects, such as detecting pattern defects. These tools typically employ electron microscopy techniques, such as scanning electron microscopy (SEM). In SEM, a primary electron beam, oriented at relatively high energy, is decelerated in a final deceleration step to land on the sample at a relatively low landing energy. The electron beam is focused as a probe spot on the sample. The interaction between the material structure at the probe 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. Secondary electrons can be emitted from the material structure of the sample. By scanning the primary electron beam, which is presented as a probe spot, across the sample surface, secondary electrons can be emitted. By collecting these emitted secondary electrons from the sample surface, the pattern inspection tool can obtain an image representing the characteristics of the material structure of the sample surface.

[0004] Typically, improvements are needed to enhance the characteristics of charged particle optics. Specifically, it is necessary to monitor various characteristics of charged particle beams, for example, to provide a basis for the desired characteristics of controlled beams. This is the procedure that needs improvement. Summary of the Invention

[0005] The embodiments provided herein disclose a charged particle optical device and a projection method.

[0006] According to a first aspect of the present invention, a charged particle optical device is provided, configured to project a charged particle multi-beam, the device comprising: A charged particle device that can switch between: (i) an operational configuration in which the device is configured to project the multi-beams onto the sample along an operational beam path extending from a source of the multi-beams to the sample; and (ii) a monitoring configuration in which the device is configured to project the multi-beams onto the detector along a monitoring beam path extending from the source to the detector; The monitored beam path automatically detects a beam path reversal midway through the operation beam path.

[0007] According to a second aspect of the present invention, a charged particle optical device is provided, configured to project a charged particle multi-beam onto a sample, the device comprising: A source, configured to output a single source beam to generate the multiple beams; An aperture array configured to form multiple beams from the source beam by blocking a certain proportion of the source beam projected toward the sample; and A detector configured to measure at least one parameter of at least a portion of the blocked proportion of the source beam.

[0008] According to a third embodiment of the present invention, a charged particle optical device is provided, configured to project a charged particle multi-beam onto a sample, the device comprising: A charged particle device comprising: An objective lens array, configured to project the multibeams onto a portion of the sample; A plurality of transducers, configured to receive signal particles emitted from the sample and to generate light in response to the received signal particles; and A light guiding configuration includes a mirror defining a plurality of apertures to allow the multiple beams to pass through the mirror toward the sample; and A photosensing assembly, the photosensing configuration being configured to guide light generated by the converters to the photosensing assembly, wherein the photosensing assembly includes: An evaluation sensor and a detector, each configured to detect the light generated by the converters; and A beam splitter configured to split the light generated by the converters into beams for use by the evaluation sensor and the detector.

[0009] According to a fourth embodiment of the present invention, a method for projecting a multi-beam of charged particles is provided, the method comprising: A charged particle device in one of its operating configurations is used to project the multi-beams onto the sample along an operating beam path from one of the multi-beam sources to the sample; and The device, configured in a monitoring state, projects multiple beams onto the detector along a monitoring beam path extending from the source to the detector; The monitoring beam path changes direction midway through the operation beam path.

[0010] According to a fifth embodiment of the present invention, a method for projecting a multi-beam of charged particles is provided, the method comprising: In one operational configuration, the multi-beam is projected onto the sample along an operational beam path from one of the multi-beam sources to one of the samples; and In a monitoring configuration, multiple beams are projected onto a detector along one of the monitoring beam paths from the source to the detector, and the monitoring beam path is deflected from the operating beam path midway through the operating beam path.

[0011] According to a sixth embodiment of the present invention, a method for projecting a charged particle multi-beam onto a sample is provided, the method comprising: Use one source to output one source beam of this multi-beam output; An aperture array is used to form multiple beams from the source beam by blocking a certain proportion of the source beam projected toward the sample; and A detector is used to measure at least one parameter of at least a portion of the blocked proportion of the source beam.

[0012] According to a seventh embodiment of the present invention, a method for projecting a charged particle multi-beam onto a sample is provided, the method comprising: One of the multiple beams is output from a single source; By blocking a certain proportion of the source beam projected toward the sample at an aperture array, multiple beams are formed from the source beam; and Ideally, a detector should be used to measure at least a portion of the blocked proportion of the source beam.

[0013] According to the eighth aspect of the present invention, a method for projecting a charged particle multi-beam onto a sample is provided, the method comprising: An objective array is used, which is configured to project the multibeams onto a portion of the sample. Multiple transducers (ideally scintillators) are used to receive signal particles emitted from the sample and to generate light in response to the received signal particles; A light guiding configuration is used to guide the light generated by the converters to a photosensing assembly, wherein the light guiding configuration includes a mirror defining a plurality of apertures to allow the multiple beams to pass through the mirror toward the sample; and A beam splitter is used to split the light generated by the converters into a plurality of beams for use by an evaluation sensor and a detector; and The evaluation sensor and the detector are used to detect the light generated by the converters.

[0014] According to the ninth aspect of the present invention, a method for projecting a charged particle multi-beam onto a sample is provided, the method comprising: Ideally, a single objective array should be used to project the multibeams onto a portion of the sample. Ideally, multiple transducers (ideally scintillators) are used to receive signal particles emitted from the sample and to generate light in response to the received signal particles; The generated light is guided to a photosensing assembly using a light guiding configuration, wherein the light guiding configuration includes a mirror defining one of a plurality of apertures, thereby allowing the multiple beams to pass through the mirror toward the sample; and Ideally, a beam splitter would split the generated light into multiple beams, preferably for use in an evaluation sensor and a detector; and Ideally, the evaluation sensor and the detector should be used to detect the generated light. Simple Explanation of the Diagram

[0015] The above and other aspects of this disclosure will become more apparent from the description of the exemplary embodiments taken in conjunction with the accompanying drawings.

[0016] [picture] [1] A schematic diagram illustrating an illustrative charged particle beam detection device.

[0017] [picture] [2] To illustrate as [picture] [1] A schematic diagram of an exemplary multi-beam device, which is part of an exemplary charged particle beam detection device.

[0018] [picture] [3] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0019] [picture] [4] is a schematic cross-sectional view of the objective lens of a detection device according to one embodiment.

[0020] [picture] [5] for [picture] [4] Bottom view of the objective lens.

[0021] [picture] [6] is [picture] [4] Modified bottom view of the objective lens.

[0022] [picture] [7] to be incorporated into [picture] [4] A magnified schematic cross-sectional view of the detector in the objective lens.

[0023] [picture] [8] is a schematic diagram illustrating a portion of an electro-optical device comprising multiple converters and optical guidance configurations.

[0024] [picture] [9] is a schematic diagram showing the location of an instance of the converter.

[0025] [picture]

[10] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0026] [picture]

[11] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0027] [picture]

[12] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0028] [picture]

[13] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0029] [picture]

[14] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0030] [picture]

[15] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0031] [picture]

[16] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0032] [picture]

[17] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0033] [picture]

[18] is a schematic diagram illustrating a portion of an electro-optical device comprising a plurality of transducers and optical guidance configurations.

[0034] [picture]

[19] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0035] [picture]

[20] is a schematic diagram of an example monitoring component.

[0036] [picture]

[21] is a schematic plan view of an example monitoring component.

[0037] [picture]

[22] is a schematic diagram of an illustrative blocking element.

[0038] [picture]

[23] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0039] [picture]

[24] is a schematic diagram of an exemplary multi-beam device according to one embodiment.

[0040] [picture]

[25] is a schematic diagram of an example detector. Implementation

[0041] [Cross-reference to related applications]

[0042] This application claims priority to European Patent Application No. 21215700.2 filed on December 17, 2021 and European Patent Application No. 22196958.7 filed on September 21, 2022, which are incorporated herein by reference in their entirety.

[0043] Detailed reference will now be made to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the drawings, wherein, unless otherwise indicated, the same reference numerals in different figures denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments of the invention. In fact, they are merely examples of apparatuses and methods conforming to the nature of the invention as enumerated in the appended claims.

[0044] Enhanced computing power in electronic devices can be achieved by significantly increasing the packing density of circuit components (such as transistors, capacitors, and diodes) on IC chips, thereby reducing the physical size of the devices. This has been achieved through increased resolution, enabling the fabrication of smaller structures. For example, a smartphone IC chip (about the size of a thumbnail and available in 2019 or earlier) could include over 2 billion transistors, each smaller than 1 / 1000th the size of a human hair. Therefore, it is not surprising that semiconductor IC manufacturing is a complex and time-consuming process with hundreds of individual steps. Even an error in a single step can significantly impact the functionality of the final product. A single defect can lead to device failure. The goal of the manufacturing process is to improve the overall yield. For example, to achieve a 75% yield for a 50-step process (where steps can indicate the number of layers formed on the wafer), each individual step must have a yield greater than 99.4%. If each individual step has a yield of 95%, the overall process yield will be as low as 7%.

[0045] While high process yields are desirable in IC chip manufacturing facilities, maintaining high substrate (i.e., wafer) throughput (defined as the number of substrates processed per hour) is also essential. Both high process yields and high substrate throughput can be affected by the presence of defects, especially if operator intervention is required to inspect for defects. Therefore, high-throughput detection and identification of micron and nanometer-scale defects using inspection equipment such as scanning electron microscopy (SEM) is crucial for maintaining high yields and low costs.

[0046] SEM comprises a scanner system and a detector system. The scanner system includes: an illumination device containing an electron source for generating primary electrons; and a projection device for scanning a sample, such as a substrate, using one or more focused beams of primary electrons. At least the illumination device or system and the projection device or system can be collectively referred to as an electron-optical system or apparatus. Primary electrons interact with the sample, generating secondary electrons. The detector system captures the secondary electrons from the sample as it is scanned, allowing the SEM to produce an image of the scanned area of ​​the sample. For high-volume inspection, some inspection devices utilize multiple focused beams of primary electrons, i.e., multi-beams. The constituent beams of a multi-beam system can be called sub-beams or fine beams. Multi-beams can scan different portions of the sample simultaneously. Therefore, multi-beam inspection devices can inspect samples at much higher speeds than single-beam SEMs.

[0047] The following describes the implementation of a known multi-beam detection device.

[0048] The figures are schematic. Therefore, for clarity, the relative dimensions of the components in the figures are exaggerated. In the following description of the figures, the same or similar reference numerals refer to the same or similar components or entities, and only differences with respect to individual embodiments are described. Although this specification and figures relate to electro-optical devices, it should be understood that the embodiments are not intended to limit this disclosure to specific charged particles. Therefore, more generally, references to electrons throughout this document can be considered as references to charged particles, where charged particles are not necessarily electrons.

[0049] For reference [picture] [1], which is a schematic diagram illustrating the charged particle beam detection device 100. [picture] The charged particle beam detection device 100 of [1] includes a main chamber 10, a loading and locking chamber 20, an electro-optical device 40, an equipment front-end module (EFEM) 30, and a controller 50. The electro-optical device 40 is located in the main chamber 10.

[0050] EFEM 30 includes a first loading port 30a and a second loading port 30b. EFEM 30 may include additional loading ports. The first loading port 30a and the second loading port 30b may, for example, receive a front-opening unit cassette (FOUP) containing a substrate to be tested (e.g., a semiconductor substrate or a substrate made of other materials) or a sample (the substrate, wafer, and sample are collectively referred to as "sample" below). One or more robotic arms (not shown) in EFEM 30 transport the sample to the loading locking chamber 20.

[0051] Loading-lock chamber 20 is used to remove gas surrounding the sample. This creates a vacuum, meaning the local gas pressure is lower than the pressure in the surrounding environment. Loading-lock chamber 20 can be connected to a loading-lock vacuum pump system (not shown), which removes gas particles from loading-lock chamber 20. Operation of the loading-lock vacuum pump system allows the loading-lock chamber to reach a first pressure below atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) can transport the sample from loading-lock chamber 20 to main chamber 10. Main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas particles from main chamber 10, causing the pressure around the sample to reach a second pressure below the first pressure. After reaching the second pressure, the sample is transported to an electro-optical device for sample detection. Electro-optical device 40 can be a multi-beam electro-optical device.

[0052] The controller 50 is electronically connected to the electro-optical device 40. The controller 50 may be a processor (such as a computer) configured to control the charged particle beam detection device 100. The controller 50 may also include a processing circuitry configured to perform various signal and image processing functions. Although the controller 50 is... [picture] [1] is shown as being outside a structure including the main chamber 10, the loading and locking chamber 20, and the EFEM 30, but it should be understood that the controller 50 may be part of that structure. The controller 50 may be located in one of the components of the charged particle beam detection device or may be distributed above at least two of the components. Although this disclosure provides an example of a main chamber 10 housing an electro-optical device, it should be noted that the form of this disclosure is not limited in its broadest sense to a chamber housing an electro-optical device. In fact, it should be understood that the foregoing principles may also be applied to other tools and other configurations of devices operating under a second pressure.

[0053] For reference [picture] [2], which is used as a drawing. [picture] [1] A schematic diagram of an exemplary multi-beam electro-optical device 40, which is a part of an exemplary charged particle beam detection device 100. The multi-beam electro-optical device 40 (also referred to herein as device 40) includes an electron source 201, a projection device 230, a motorized stage 209, and a sample holder 207. The electron source 201 and the projection device 230 may be collectively referred to as an illumination device. The sample holder 207 is supported by the motorized stage 209 to hold a sample 208 (e.g., a substrate or a mask) for detection. The multi-beam electro-optical device 40 further includes an electronic detection device 240.

[0054] The electron source 201 may include a cathode (not shown) and an extractor or anode (not shown). During operation, the electron source 201 is configured to emit electrons from the cathode as primary electrons. The primary electrons are extracted or accelerated by the extractor and / or anode to form a source beam (or primary electron beam) 202.

[0055] The projection device 230 is configured to convert the source beam 202 into a plurality of sub-beams 211, 212, 213 and guide each sub-beam onto the sample 208. Although three sub-beams are shown for simplicity, there may be tens, hundreds, or thousands of sub-beams. These sub-beams may be referred to as fine beams.

[0056] Controller 50 can be connected to [picture] [1] Various components of the charged particle beam detection device 100, such as the electron source 201, the electron detection device 240, the projection device 230, and the motorized stage 209. The controller 50 can perform various image and signal processing functions. The controller 50 can also generate various control signals to control the operation of the charged particle beam detection device (including the charged particle multi-beam device).

[0057] Projection device 230 can be configured to focus primary sub-beams 211, 212, and 213 onto sample 208 for detection, and can form three detection spots 221, 222, and 223 on the surface of sample 208. Projection device 230 can be configured to deflect primary sub-beams 211, 212, and 213 to scan detection spots 221, 222, and 223 across individual scanning areas in a segment of the surface of sample 208. In response to the primary sub-beams 211, 212, and 213 incident on the detection spots 221, 222, and 223 on sample 208, electrons are generated by sample 208, including secondary electrons and backscattered electrons. Secondary electrons typically have an electron energy of ≤ 50 eV, and backscattered electrons typically have an electron energy between 50 eV and the landing energy of primary sub-beams 211, 212, and 213.

[0058] Electron detection device 240 is configured to detect secondary electrons and / or backscattered electrons and generate corresponding signals. These signals are sent to controller 50 or a signal processing system (not shown) for example, to construct an image of the corresponding scanned area of ​​sample 208. Ideally, the electron detection device is integrated into the projection device. Alternatively, the electron detection device may be separate from the projection device, wherein a secondary electron optical column (or device) is provided to guide secondary electrons and / or backscattered electrons to the electron detection device.

[0059] The controller 50 may include an image processing system comprising an image acquisition unit (not shown) and a storage device (not shown). For example, the controller may include a processor, computer, server, mainframe computer, terminal, personal computer, any type of mobile computing device, or similar, or combinations thereof. The image acquisition unit may include at least a portion of the controller's processing functionality. Therefore, the image acquisition unit may include at least one or more processors. The image acquisition unit may be communicatively coupled to an electronic detection device 240 of the device 40 that enables signal communication, such as an electrical conductor, fiber optic cable, portable storage media, IR, Bluetooth, Internet, wireless network, radio, and others, or combinations thereof.

[0060] The image acquisition device can acquire one or more images of a sample based on imaging signals received from the electronic detection device 240. The imaging signals may correspond to a scanning operation used for charged particle imaging. The acquired image may be a single image containing a plurality of imaging regions. The single image may be stored in a memory. The single image may be an original image that can be divided into a plurality of regions. Each region may contain an imaging region containing the features of sample 208. The acquired image may contain multiple images of a single imaging region of sample 208 sampled multiple times within a time period. Multiple images may be stored in a memory. The controller 50 can be configured to perform image processing steps using multiple images of the same location of sample 208.

[0061] The controller 50 may include a measurement circuitry (e.g., an analog-to-digital converter) to obtain the distribution of the detected secondary electrons. The electron distribution data collected during the detection time window can be combined with the corresponding scan path data of each of the primary sub-beams 211, 212, and 213 incident on the sample surface to reconstruct an image of the structure of the sample under test. The reconstructed image can be used to reveal various features of the internal or external structure of the sample 208. The reconstructed image can also be used to reveal any defects that may be present in the sample.

[0062] The controller 50 controls the motorized stage 209 to move the sample 208 during the detection of the sample 208. The controller 50 enables the motorized stage 209 to move the sample 208 in one direction (preferably continuously) at least during sample detection, for example, at a constant speed. The controller 50 controls the movement of the motorized stage 209 such that the controller varies the speed of movement of the sample 208 depending on various parameters. For example, the controller may control the stage speed (including its direction) depending on the characteristics of the detection steps of the scanning procedure.

[0063] [picture] [3] is a schematic diagram of an evaluation apparatus comprising an electron source 201 and an electron optics device (or electron optics column). (In another configuration, the source is part of the electron optics device). The electron optics device comprises a plurality of electron optical elements. Electro-optics elements are any elements that influence (e.g., guide, shape, or focus) the electron beam and can utilize electric and / or magnetic fields. The electron source 201 guides electrons toward an array of condenser lenses 231 that form part of the electron optics device. The electron source is ideally a high-brightness thermal field emitter with a good trade-off between brightness and total emission current. There may be tens, hundreds, or thousands of condenser lenses 231. The condenser lenses 231 may comprise multi-electrode lenses and have a construction based on EP1602121A1, the literature of which is hereby incorporated by reference in particular to the disclosure of a lens array for splitting an electron beam into a plurality of sub-beams, wherein the array provides a lens for each sub-beam. The condenser lens array thus functions as a beam splitter, beam splitter, beam generator, or beam separator. The condenser lens array can take the form of at least two plates, which act as electrodes, with apertures in each plate aligned with each other and corresponding to the locations of sub-beams. During operation, at least two of these plates are maintained at different potentials to achieve the desired lensing effect. The plates thus have an array of apertures, each aperture corresponding to the path of a sub-beam. The plate positioned in the most counter-current direction is configured to act as a beam separator and can be referred to as an aperture array for beam limiting. In different configurations, the beam separator may be part of or associated with the condenser lens array, having a function different from lensing the sub-beams. Between the plates of the condenser lens array is an electrically insulating plate, for example made of an insulating material such as ceramic or glass, having one or more apertures for the sub-beams.

[0064] In one configuration, the condenser lens array is formed by three plate arrays in which charged particles have the same energy upon entering and exiting each lens; this configuration can be called an ensemble lens. The beam energy entering and exiting the ensemble lens is identical. Therefore, dispersion occurs only within the ensemble itself (between the entry and exit electrodes), thereby limiting off-axis chromatic aberration. When the condenser lens is thin, such as a few millimeters, this type of aberration has a small or negligible effect.

[0065] Each focusing lens in the array guides electrons into individual sub-beams 211, 212, and 213, which are focused at their respective intermediate focal points 233. The sub-beams diverge relative to each other. A deflector 235 is located at the intermediate focal point 233. The deflector 235 is positioned in the beam paths at or at least around the corresponding intermediate focal point 233 or convergence point (i.e., the point of convergence). The deflector is positioned in the beam path at the intermediate image plane of the associated beam (i.e., its focal point or convergence point). The deflector 235 is configured to operate on the individual beams 211, 212, and 213. Deflector 235 is configured to bend the individual fine beams 211, 212, and 213 by a certain amount to effectively ensure that the main beam (which may also be referred to as the beam axis) is incident substantially normally (i.e., substantially at 90° to the normal surface of the sample) onto the sample 208. Deflector 235 may also be referred to as a collimator or collimator deflector. Deflector 235 effectively collimates the paths of the fine beams such that, in the direction against the flow of the deflector, the paths of the fine beams are divergent relative to each other. In the direction with the flow of the deflector, the paths of the fine beams are substantially parallel relative to each other, i.e., substantially collimated. A suitable collimator is the deflector disclosed in European Patent Application No. 20156253.5, filed on February 7, 2020, which is incorporated herein by reference for its application to deflectors in multi-beam arrays.

[0066] Below deflector 235 (i.e., in the downstream direction of source 201 or further away from source 201), there is a control lens array 250, which includes control lenses 251 for each sub-beam 211, 212, 213. The control lens array 250 may include at least two (e.g., three) plate electrode arrays connected to individual potential sources. The function of the control lens array 250 is to optimize the beam angle relative to the beam reduction rate and / or control the beam energy delivered to objectives 234, each of which guides its respective sub-beams 211, 212, 213 onto sample 208. The control lenses pre-focus the sub-beams (e.g., apply focusing action to the sub-beams before they reach objective 234). Pre-focusing can reduce sub-beam divergence or increase sub-beam convergence rate. The control lens array and objective array operate together to provide a combined focal length. Combined operation without an intermediate focal point reduces aberration risks. It should be noted that the references for the reduction rate and the angle refer to variations in the same parameters. In an ideal configuration, the product of the reduction rate and the corresponding angle is constant over a range of values.

[0067] Objective 234 is arranged in the form of an objective array. Objective 234 can be configured to reduce the electron beam by a factor greater than 10, ideally in the range of 50 to 100 or greater. Objective 234 can be a single lens. At least chromatic aberrations produced in the beam by the condenser lens and the corresponding downstream objective can be mutually canceled.

[0068] An electron detection device 240 is positioned between the objective lens 234 and the sample 208 to detect secondary and / or backscattered electrons emitted from the sample 208. An exemplary configuration of the electron detection system is described below.

[0069] Depending on the situation, the scanning deflector array 260 is positioned between the control lens array 250 and the array of objectives 234. The scanning deflector array 260 includes scanning deflectors for each sub-beam 211, 212, 213. Each scanning deflector is configured to deflect the individual sub-beams 211, 212, 213 in one or two directions to scan the sub-beams throughout the sample 208 in one or two directions.

[0070] [picture] [3] The device can be configured to control the landing energy of electrons on the sample. Depending on the nature of the sample being evaluated, the landing energy can be selected to increase the emission and detection of secondary electrons. A controller provided to control the objective lens 234 can be configured to control the landing energy by changing the potential of the electrodes applied to the control lens and the objective lens. The control lens and the objective lens work together and can be referred to as the objective lens assembly. Depending on the nature of the sample being evaluated, the landing energy can be selected to increase the emission and detection of secondary electrons. The controller can be configured to control the landing energy to any desired value or a desired predetermined value among a plurality of predetermined values ​​within a predetermined range. In one embodiment, the landing energy can be controlled to a desired value within the range of 1000 eV to 5000 eV.

[0071] Ideally, landing energy is primarily altered by controlling the energy of electrons leaving the control lens. The potential difference within the objective lens is preferably kept constant during this change, allowing the electric field within the objective lens to remain as high as possible. Furthermore, the potential applied to the control lens can be used to optimize the beam angle and reduction ratio. The control lens can also be called a refocusing lens because it can be used to correct the focusing position in response to changes in landing energy. Using a control lens array allows the objective array to operate at its optimal electric field strength. Details of the electrode structure and potentials used to control landing energy are disclosed in EPA 20158804.3, which is incorporated herein by reference.

[0072] Since any off-axis aberrations generated in the narrow beam path originate, or at least primarily originate, in the condenser lens 231, they can be... [picture] [3] The landing energy of the electrons in the system is controlled. [picture] The objective 234 of the system shown in [3] does not need to be a single lens. This is because off-axis aberration will not occur in the objective when the beam is collimated. Off-axis aberration can be better controlled in the condenser lens than in the objective 234. By making the condenser lens 231 substantially thinner, the contribution of the condenser lens to off-axis aberration (specifically chromatic off-axis aberration) can be minimized. The thickness of the condenser lens 231 can be varied to tune the chromatic off-axis contribution, thereby balancing other contributions of chromatic aberration in the individual fine beam paths. Therefore, the objective 234 can have two or more electrodes. The beam energy entering the objective can be different from its energy leaving the objective, for example, to provide a decelerating objective. Furthermore, when using two electrodes, as few electrodes as possible are used so that the lens array can achieve a smaller volume.

[0073] In some embodiments, the electro-optical device further includes one or more aberration correctors that reduce one or more aberrations in the sub-beams. In one embodiment, at least a subset of the aberration correctors are located in or directly adjacent to one of the intermediate focal points (e.g., in or near the intermediate image plane). The sub-beams have a minimum cross-sectional area in or near a focal plane such as the intermediate plane. This provides more space for the aberration correctors compared to the space obtained elsewhere, i.e., in the upstream or downstream direction of the intermediate plane (or compared to the space obtained in an alternative configuration without an intermediate image plane).

[0074] In one embodiment, an aberration corrector located in or directly adjacent to the intermediate focal point (or intermediate image plane or focal point) includes a deflector to correct for sources 201 appearing at different locations in different beams. The corrector can be used to correct macroscopic aberrations caused by the source, which prevent proper alignment between the sub-beams and their corresponding objectives. In some cases, it is necessary to position the corrector as far as possible in the countercurrent direction. In this way, small-angle corrections can achieve large displacements at the sample, allowing the use of a weaker corrector. Ideally, the corrector is positioned to minimize the introduction of additional aberrations. Alternatively or additionally, other non-uniformities in the source beam can be corrected; that is, aberrations in the source beam uniformity can be corrected.

[0075] Aberration correctors can correct other aberrations that prevent proper column alignment. Such aberrations can also cause misalignment between the sub-beams and the corrector. For this reason, alternatively, it may be necessary to position the aberration corrector at or near the condenser lens 231 (e.g., where each aberration corrector is integrated with or directly adjacent to one or more of the condenser lenses 231). This is desirable because at or near the condenser lens 231, aberrations will not yet have caused displacement of the corresponding sub-beams, as the condenser lens 231 is vertically close to or coincident with the beam aperture. That is, correction of any angular error by the corrector will require less positional displacement than if the corrector were positioned further downstream. Correction of such aberrations further downstream (e.g., at the intermediate focal point) can be affected by misalignment between the sub-beams 211, 212, 213 and the corrector. However, the challenge in positioning the corrector at or near the condenser lens 231 is that the sub-beams at this location have relatively large cross-sectional areas and relatively small pitches compared to locations further downstream. In cases with volume constraints, the corrector array or additional corrector array can be located away from these preferred locations, such as between the condenser lens array and the intermediate focal point.

[0076] In some embodiments, at least a subset of aberration correctors are integrated with or directly adjacent to one or more of the objectives 234. In one embodiment, these aberration correctors reduce one or more of: field curvature; focusing error; and astigmatism. Alternatively or additionally, one or more scanning deflectors (not shown) may be integrated with or directly adjacent to one or more of the objectives 234 to scan sub-beams 211, 212, 213 over sample 208. In one embodiment, the scanning deflector described in US 2010 / 0276606 may be used, the entire document of which is incorporated herein by reference.

[0077] The aberration corrector can be either the CMOS-based individually programmable deflector disclosed in EP2702595A1 or the multi-stage deflector array disclosed in EP2715768A2; the descriptions of the fine beam manipulators in both documents are incorporated herein by reference. An aberration corrector of this design can exist for each fine beam, i.e., an individual fine beam corrector. Individual fine beam correctors can be arrayed across multiple beams, which can be called a corrector array.

[0078] In one embodiment, the objective array mentioned in earlier embodiments is an array objective. Each element in the array is a microlens that operates different beams or beam groups in a multi-beam array. The electrostatic array objective has at least two plates, each having a plurality of holes or apertures. The position of each hole in one plate corresponds to the position of a corresponding hole in the other plate. The corresponding holes operate in use on the same beam or beam group in the multi-beam array. A suitable example of the lens type used for the elements in the array is a two-electrode deceleration lens. Each electrode can be considered a lens in itself; each electrode can be considered an electro-optical element (or electro-optical assembly). Between the plates (e.g., electrodes) of the objective array is an electrically insulating plate, for example, made of an insulating material such as ceramic or glass, having apertures for one or more sub-beams.

[0079] The bottom electrode of the objective lens is a wafer detector, such as a CMOS wafer detector, integrated into a multi-beam manipulator array. The detector array is integrated into the objective lens to replace the secondary pillar. The wafer is preferably oriented to face the sample (due to the small distance (e.g., 100 μm) between the sample and the bottom of the electro-optics system). In one embodiment, a capture electrode is provided for capturing secondary electronic signals. The capture electrode may be formed in a metal layer of a device (e.g., a CMOS device) on and / or in the wafer. The capture electrode may form the bottom layer of the objective lens. The capture electrode may form the bottom surface of the detector wafer (e.g., a CMOS wafer). The CMOS wafer may be a CMOS wafer detector. The wafer, such as a CMOS wafer, may be integrated into the sample facing the surface of the objective lens assembly. The capture electrode is an example of a sensor unit for detecting secondary electrons. The capture electrode may be formed in other layers. Power and control signals of the integrated device on the wafer (e.g., CMOS) may be connected to the integrated device via silicon vias. For stability, the bottom electrode preferably consists of two components: a wafer, such as a CMOS wafer; and a passive Si board with holes. The board shields the integrated device (e.g., CMOS) from a high electric field.

[0080] [picture] [4] shows an exemplary embodiment of a multibeam objective lens 401 illustrated in schematic cross-section. A detector module 402 is provided on the output side of the objective lens 401 (the side facing the sample 208). The detector module 402 is an example of an electronic detection device. [picture] [5] is a bottom view of a detector module 402, which includes a substrate 404 on which a plurality of capture electrodes 405 are disposed, each of which surrounds a beam aperture 406. The beam aperture 406 is large enough not to block any of the primary electron beams. The capture electrodes 405 can be considered as examples of sensor units that receive backscattered or secondary electrodes and generate a detection signal (in this case, current). The beam aperture 406 can be formed by etching through the substrate 404. [picture] In the configuration shown in [5], the beam aperture 406 is displayed in a rectangular array. The beam aperture 406 can also be configured in different ways, for example, using... [picture] The hexagonal close-packed array configuration depicted in [6].

[0081] [picture] [7] A portion of the detector module 402 is depicted in cross-section at a large scale. Capture electrodes 405 form the bottommost (i.e., closest to the sample) surface of the detector module 402. In operation, the array of capture electrodes 405 faces the sample 208. A logic layer 407 is disposed between the capture electrodes 405 and the body of the silicon substrate 404. The logic layer 407 may include amplifiers (e.g., transimpedance amplifiers), analog-to-digital converters, and readout logic. In one embodiment, each capture electrode 405 has one amplifier and one analog-to-digital converter. The logic layer 407 and the capture electrodes 405 can be fabricated using CMOS processes, wherein the capture electrodes 405 form the final metallization layer.

[0082] Wiring layer 408 is disposed on the back side of substrate 404 and connected to logic layer 407 via through-silicon vias 409. The number of through-silicon vias 409 need not be the same as the number of beam apertures 406. Specifically, if the electrode signals are digitized in logic layer 407, only a few through-silicon vias are needed to provide the data bus. Wiring layer 408 may include control lines, data lines, and power lines. It should be noted that despite the presence of beam apertures 406, there is still sufficient space for all necessary connections. Bipolar or other manufacturing techniques can also be used to fabricate the detection module 402. Printed circuit boards and / or other semiconductor wafers may be disposed on the back side of detector module 402.

[0083] [picture] [4] A three-electrode objective lens is described, but it should be understood that any other type of objective lens, such as a two-electrode lens, may also be used.

[0084] In another configuration, the detector array is associated with (alternatively or additionally with) another electrode of the objective lens array. The detector array may also be associated, alternatively, with another plate such as an electrode, which is a lens electrode, such as one associated with an objective lens integrated into the objective lens array or also close to the countercurrent direction of an objective lens, such as a control lens array. In one configuration, the detector array is located countercurrently to the objective lens array and any electro-optical elements associated with the objective lens. Detector elements of the detector array may be associated with individual sub-beams. Detector elements may include charge detection, scintillators, and PIN detection elements. In a configuration where the detector elements include scintillators, the detectors may be positioned on one side of the sub-beam path such that the sub-beams are delivered to that side of the individual detector element.

[0085] Deflection elements, such as Wien filters or arrays of Wien filters, can be positioned between the detector array and the objective lens. Such Wien filters allow sub-beams to pass through the Wien filter toward an undeflected sample, but direct signal particles from the sample toward the detector elements. Optical transducers (e.g., optical detectors) can be positioned to convert the light generated by the scintillator into an electronic signal. The optical transducers can be coplanar and even in direct contact with the scintillator detector elements. Such optical transducers are described in European Patent Application No. 21183803.2, filed July 5, 2021, which relates at least to the architecture and use of optical transducers associated with scintillators and detectors for detecting signal particles, and is incorporated herein by reference.

[0086] In an alternative embodiment, a condenser lens array may not be provided. Instead, sub-beams 211, 212, 213 may be generated from the source beam at the objective lens array or associated with the objective lens array, in the countercurrent direction of the objective lens array, and near an associated plate (e.g., electrodes) close to the objective lens array. The control lens array may be an example of such an associated plate. Between adjacent plates is an electrically insulating plate made of, for example, an insulating material such as ceramic or glass, having apertures for one or more sub-beams. The objective lens array may be characterized by an upper beam limiter and a beam shaping limiter. In this configuration, source 201 provides a beam of charged particles (e.g., electrons). Sub-beams may be derived from the beam, for example, using a beam limiter (e.g., an upper beam limiter) that defines a beam-limiting aperture array. The upper beam limiter defines the beam-limiting aperture array and acts as a beam splitter or sub-beam generator. The upper beam limiter may be located, for example, in the countercurrent direction of deflectors 235 in the array, such as one deflector for each sub-beam. The beam shaping limiter is located in the forward direction of the upper beam limiter. Another electro-optical element, such as an objective array, is positioned between the upper beam limiter and the beam shaping limiter. During operation, the beam shaping limiter may be closer to the sample-facing surface of the electro-optical element than the objective array.

[0087] In some embodiments, [picture] [3] illustrates that deflector 235 is the first deflecting or focusing electron optical array element in the beam path in the downstream direction of source 201. In another configuration, a giant collimator can be positioned in the upstream direction of the objective array. Thus, the giant collimator operates the beam from the source before multi-beam generation. A magnetic lens can be used as the giant collimator. When a giant collimator is provided, the downstream collimator deflector 235, for example, the upper beam limiter, can be omitted. []

[0088] In another configuration, a giant scanning deflector can be positioned in the countercurrent direction to the objective array. Therefore, the giant scanning deflector operates the beam from the source before multi-beam generation. The giant scanning deflector can be positioned in the cocurrent direction to the giant collimator. When the giant scanning deflector is positioned, the scanning deflector array 260 can be omitted. []

[0089] In other embodiments, both a giant scanning deflector and a scanning deflector array 260 are provided. In this configuration, scanning sub-beams above the sample surface can be achieved by better synchronizing and jointly controlling the giant scanning deflector and the scanning deflector array 260.

[0090] As described above, multiple electro-optical components in an electro-optical column (such as a multi-beam SEM or multi-beam lithography machine) are typically required to generate multiple beams. These electro-optical components form electro-optical apertures, lenses, deflectors, and perform other beam manipulations. Such electro-optical components may comprise arrays of electro-optical elements (one or more of which may be in the form of MEMS elements) and require precise alignment to allow all beams to land on a target (e.g., a sample or detector). Electro-optical components (such as electro-optical arrays) that are close to each other can be stacked vertically and aligned. Some techniques for aligning electro-optical components include collimator components, such as collimator arrays in electro-optical devices, as described herein. These components can be operated to achieve improved alignment. One such electro-optical component is a collimator that can have both alignment and collimation functions. Alternatively, other correctors, such as those operating in the countercurrent direction of a beam-limiting aperture array, may exist in and be associated with a condenser lens (e.g., a condenser lens array), such as in the near-current direction of the condenser lens, a collimator associated with the intermediate focal point 233, and an objective lens array.

[0091] [picture] [8] A scintillator-based detector method for promoting close beam packing at sample 208 is schematically depicted. For ease of description, [picture] [8] Only a portion of an example of an electro-optical device is depicted near one of the objective arrays 403 and sample 208. The depicted objective array 403 has two plates or electrodes 301, 302. This is the minimum number of plates used for a practical objective array. However, any number of plates may be available for the designer to choose, such as three, four, five, seven, or ten or more plates. Each plate provides additional degrees of freedom for controlling the sub-beam array. In one configuration, two or more plates may operate as objectives, and the remaining plates, close to the selected objective plates, may be associated plates with the objective array and may be assigned a different name, such as a control lens array.

[0092] Electro-optical devices may include [picture] [8] shows an aperture array (forming sub-beams in a multi-beam array) and a collimator in the countercurrent direction of the electro-optical device. The aperture array generates a plurality of beams. The collimator collimates the path of the beams. In this example, the detector includes a plurality of transducers 410 and a photosensor 412. The transducers 410 may be scintillators. The plurality of transducers 410 may be referred to as a transducer array. The dashed path depicts a representative path of the beam. The transducers 410 receive signal particles emitted from sample 208. The transducers 410 generate light 411 in response to the received signal particles. The transducers 410 may include a luminescent material that absorbs energy from incoming particles and re-emits the absorbed energy as light. The photosensor 412 detects the light 411 generated by the transducers 410 and thereby indirectly detects the signal particles.

[0093] A light guiding configuration is provided to reduce or avoid the need for optical fiber. The light guiding configuration guides light 411 generated by converter 410 to photosensor 412. The light guiding configuration includes a mirror 414. The light 411 generated by converter 410 is reflected towards photosensor 412 by mirror 414. (Therefore, the mirror is one embodiment of a radiative reflective surface that reflects radiation having a wavelength corresponding to the scintillator). Optics 418 can be provided for controlling the propagation of the reflected light between mirror 414 and photosensor 412. Optics 418 can, for example, image the reflected light onto photosensor 412. This configuration allows photosensor 412 to be positioned outside the portion through which the beam of the column passes (i.e., away from the beam configuration), such as... [picture] [8] is schematically indicated by the laterally protruding housing 420. The photosensor can be located away from the electromagnetic field of the electro-optical components. If not blocked, electromagnetic interference between the photosensor and the electro-optical components can be reduced. The photosensor 412 can therefore be positioned at a radially distal location relative to the path of the beam. For example, the distance between the central longitudinal axis of the plurality of beams and the outermost radial beam is less than the distance from the longitudinal axis to the photosensor 412. Therefore, the photosensor 412 does not restrict the close packing of the beams. Furthermore, the photosensor 412 can be easily implemented because there is less spatial constraint at the location of the photosensor 412 than there is spatial constraint closer to the longitudinal axis. In addition, the mirror redirects the light without the need for optical fibers or the like, thereby further reducing the restriction on the close packing of the beams. The light sensor 412 may be disposed inside or outside the vacuum region, for example, wherein a window or other configuration is configured to transmit light from the mirror 414 (in the vacuum region) to the light sensor 412 (outside the vacuum region).

[0094] The photosensor 412 can be implemented using any of a variety of known devices for detecting light, such as a charge-coupled device (CCD). In some configurations, the photosensor 412 includes an array of photodiodes. The photosensor 412 can be configured or selected to have a wavelength sensitivity matched to the scintillator spectrum (i.e., the wavelength spectrum of photons emitted by the scintillator element). Appropriate data lines 422 of various known configurations can be provided for extracting data representing the detected light.

[0095] In some configurations, the light guiding configuration includes one or more optical fibers between the mirror 414 and the photosensor 412. The optical fibers collect light from the mirror and guide it to a location further away from the portion of the beam that passes through the pillar, such as away from the path of the beam configuration. Using optical fibers in this way provides additional flexibility for positioning the photosensor 412 (and associated electronics and / or data lines). The photosensor 412 can be positioned further away from the pillar. The photosensor 412 can be positioned outside the direct line of sight of the mirror 412.

[0096] In some configurations, the optical guiding configuration and at least a portion of the objective lens array are structurally connected. A support for mirror 414 may be structurally connected to and / or support at least the nearest electrode of objective lens array 403. For example, the support for mirror 414 may be structurally connected to the support closest to the electrode. In a different configuration, the mirror has independent and separate structural supports.

[0097] To allow multiple beams to pass through mirror 414, mirror 414 is configured to define multiple apertures 416 passing through mirror 414. Apertures 416 are positioned to allow multiple beams to pass through mirror 414 toward sample 208. Each aperture 416 may therefore correspond to one or more of the beams (i.e., positioned to allow one or more beams to pass through the aperture).

[0098] In some configurations, each converter 410 is configured to receive signal particles from the aperture array 401 originating from the interaction between the sample 208 and each of the individual beams. Thus, for a given position of the pillar relative to the sample 208, each converter 410 receives signal particles from a different portion of the sample 208.

[0099] In some configurations, the transducers are arranged in an array. The array is orthogonal to the paths of multiple beams (i.e., substantially orthogonal to each of the paths). The array may contain a two-dimensional pattern. The two-dimensional pattern may be in the form of a grid. The configuration may be hexagonal or linear grid. The transducer array may geometrically correspond to the arrays of beams 211, 212, and 213. The transducers may be in a ring-shaped form surrounding an aperture for the path corresponding to the primary beam (or more than one primary beam). Therefore, the aperture may be defined by individual scintillators. Each transducer element in the transducer array may be in a ring-shaped form.

[0100] In one configuration, the converter 410 is positioned in the countercurrent direction of at least one electrode 302 of the objective array 403, or associated with the objective array. The converter 410 may be positioned in the countercurrent direction facing the electrode 302 of the sample 208. In some configurations, such as... [picture] As illustrated in [8], the transducer 410 is supported by one of the electrodes 301 of the objective array 403. In the example shown, the transducer 410 is supported by the electrode 301 of the objective array 403 furthest from the sample 208. The transducer 410 is at the same level as the uppermost portion of the electrode 301 (farthest from the sample 208). In one embodiment, the transducer 410 is supported by the most countercurrent direction electrode associated with the objective array. In some configurations, the scintillator 410 is positioned in the countercurrent direction of the objective array 403 (or even the most countercurrent direction electrode associated with the objective array), for example directly in the countercurrent direction of the objective array (e.g., at a small distance and / or there is no intervening element between the transducer 410 and the objective array 403, or the most countercurrent direction electrode associated with the objective array 403).

[0101] [picture] [9] Other example locations of the transducer 410 relative to a portion of the example objective array 403 are shown. Although two electrodes 301, 302 are depicted, the location of the transducer can be applied to the electrodes of an objective array having any number of electrodes, and any number of electrodes can be associated with the objective array for proximity to the objective array. Vertical dashed lines depict the paths of the two example beams through the respective objectives of the objective array 403. Five example locations of the transducer 410 are shown. The transducer 410 can be located at one or more of these five locations. Some locations are more advantageous than others. Less advantageous locations can be combined with other locations to capture sufficient signal. The transducer 410 can be located below the electrode 302 of the objective array 403 closest to the sample 208 (e.g., facing the sample 208). The transducer 410 can be positioned above the electrode 302 closest to the sample 208 and below the electrode 301 adjacent to the electrode 302 closest to the sample 208. In this case, the converter 410 may be closer to and / or attached to the electrode 302 closest to the sample 208. Alternatively, the converter 410 may be closer to and / or attached to the adjacent electrode 301. Alternatively, the converter 410 may be positioned above the adjacent electrode 301, directly adjacent to and / or attached to the adjacent electrode 301, or separated from and / or positioned further away from the adjacent electrode 301.

[0102] In one configuration, transducers 410 surround an aperture 417 configured to allow individual beams of a plurality of beams to pass through. The aperture 417 may be defined within the electrodes of the objective lens or within a single aperture body. In this configuration, each transducer surrounds the path of its respective beam. Each transducer 410 may be positioned to receive signal electrons propagating generally along the path of the beam in the opposite direction to the beam. The signal electrons may thus strike the transducer 410 in the annular region. Due to the aperture allowing the corresponding primary beam to pass through in the opposite direction, the signal electrons do not strike the central region of the annulus.

[0103] In some configurations, each converter 410 comprises multiple sections. These different sections can be referred to as different bands. This converter 410 can be called a partition converter. The sections of the converter may surround a defined aperture within the converter. Signal particles captured by the converter sections can be combined into a single signal or used to generate independent signals.

[0104] The partitioned converter 410 can be associated with one of the beams 211, 212, and 213. Therefore, multiple portions of a converter 410 can be configured to detect signal particles emitted from the sample 208 relative to one of the beams 211, 212, and 213. A converter comprising multiple portions can be associated with one of the apertures of at least one of the electrodes of the objective array 403. More specifically, a converter 410 comprising multiple portions can be configured around a single aperture.

[0105] The portions of the partition converter can be separated in a variety of different ways, such as radially, annularly, or any other suitable manner. Preferably, these portions have similar angular sizes and / or similar areas and / or similar shapes. The separated portions can be provided as a plurality of segments, a plurality of annular portions (e.g., a plurality of concentric annular rings or loops), and / or a plurality of sector portions (i.e., radial portions or sectors). The converter 410 can be radially partitioned. For example, the converter 410 can be provided as an annular portion comprising two, three, four, or more portions. More specifically, the converter 410 can include an inner annular portion surrounding the aperture and an outer annular portion radially outward from the inner annular portion. Alternatively, the converter 410 can be angularly partitioned. For example, the scintillator 410 can be provided as a sector portion comprising two, three, four, or more portions (e.g., eight, twelve, etc.). If the converter 410 is provided as two sectors, each sector portion can be a semicircle. If the converter 410 is provided as four sectors, each sector portion may be a quarter circle. In one example, the converter 410 is divided into quarter circles, that is, four sector portions. Alternatively, the converter 410 may have at least one segment portion.

[0106] Providing multiple sections concentrically or otherwise can be advantageous because different sections of the converter 410 can be used to detect different signal particles, which may be small-angle and / or large-angle signal particles, or secondary signal particles and / or backscattered signal particles. This configuration of different signal particles can be suitable for a concentric partition converter 410. Backscattered signal particles at different angles can be beneficial in providing different information. For example, for signal particles emitted from a deep aperture, small-angle backscattered signal particles are likely to originate more from the bottom of the aperture, and large-angle backscattered signal particles are likely to originate more from the surface and material around the aperture. In an alternative example, small-angle backscattered signal particles are likely to originate more from deeper embedded features, and large-angle backscattered signal particles are likely to originate more from the sample surface or material above the embedded features. It should be noted that the configuration of FIG8 may have limited capability for detecting backscattered signal particles; for example, this configuration may be limited to detecting backscattered signal particles with small-angle backscattering. That is, the backscattered signal particles that can be detected using this configuration are limited by the relatively large distance between the sample 208 and the converter 401 and the relatively narrow path from the sample 208 to each converter 401 (e.g., due to the individual apertures passing through the electrode 302). In this configuration, the converter is unlikely to have concentric portions due to the low angular range of backscattered signal particles that this converter can detect.

[0107] The converter 410 may be provided as a converter element, each associated with one or more of the plurality of beams. Alternatively or additionally, the converter 410 may be provided as a single-unit converter defining a plurality of apertures, each aperture corresponding to one or more of the plurality of beams. In some configurations, the converter is configured as a strip array. Each strip may correspond to a primary beam group. The beams may comprise a plurality of beam columns, and each group may correspond to a separate column.

[0108] The description of Figure 9 can also be applied to other types of detector elements, such as charge detector elements and semiconductor elements, such as PIN detector elements.

[0109] [picture]

[10] is a schematic diagram of an exemplary multi-beam electro-optical device according to one embodiment. The electro-optical device is configured to project multiple electron beams. The electro-optical device includes electronic components (also referred to as electro-optical elements or electro-optical columns). The electro-optical device may be configured as described in any of the embodiments described above. [picture] The configuration shown in

[10] is similar to [picture] The configuration shown in [3], but without the control lens array 250. In one embodiment, [picture] The electro-optical device shown in

[10] includes a control lens array (or any number of other associated plates of objective lens arrays) as described above. In other embodiments, the electro-optical device is similar to another of the configurations described above, such as a configuration including a giant collimator and a giant scanning deflector instead of collimator deflector 235 and scanning deflector array 260. In other embodiments, the electro-optical device is similar to another of the configurations described above, such as... [picture] The configuration shown in [8].

[0110] In one embodiment, the electronic device can be switched between: (i) an operational configuration, wherein the device is configured to project multiple beams onto sample 208 along an operational beam path; and (ii) a monitoring configuration, wherein the device is configured to project multiple beams onto a detector (or a monitoring detection system) along a monitoring beam path. The operational beam path extends from the source 201 of the multiple beams to sample 208. The monitoring beam path extends from source 201 to the detector. For example, the operational configuration can be used to perform detection of sample 208 or to perform metrology. In the operational configuration, signal electrons emitted from the sample can be detected as described above. In the operational configuration, the detector array 240 is used to detect signal particles in the operational configuration. In one embodiment, in the monitoring configuration, for example, a monitoring detection system is used to monitor the multiple beams from source 201.

[0111] like [picture] As shown in

[10] , in one embodiment, the monitored beam path self-detects a beam path reversal midway through the operation of the beam path. Sample 208 can be separated from the monitored beam path. In the monitoring configuration, multiple beams are intercepted in the reverse direction of sample 208. The multiple beam signals are monitored directly without interacting with sample 208; that is, the sub-beams in the multiple beams are monitored directly. The primary beam, i.e., the sub-beams (which may be referred to as the primary signal), is monitored, rather than the signal particles from sample 208, which may be referred to as the secondary signal.

[0112] In one embodiment, at least one parameter of at least a portion of the multi-beam is monitored. For example... [picture] As shown in

[10] , in one embodiment, sub-beams 211, 212, and 213 of the multi-beam system are monitored. Alternatively, the source beam 202 of the multi-beam system can be monitored (see, for example, referenced below). [picture]

[16] [To the image]

[17] as described. In one embodiment, the uniformity of the multiple beams is monitored. The uniformity of the multiple beams may be a measure of the variation in characteristics across the multiple beams. These characteristics may be, for example, intensity or focus. Alternatively or alternatively, one or more aberrations of the multiple beams may be monitored. For example, field curvature, distortion, and astigmatism may be monitored. Alternatively or alternatively, the alignment of the multiple beams may be monitored. For example, the alignment of sub-beams 211, 212, 213 with one or more sets of apertures (e.g., apertures in the objective lens assembly or mirror) may be monitored. Alternatively or alternatively, the focus of the multiple beams may be monitored. By monitoring at least one parameter of at least a portion of the multiple beams, deviations from nominal values ​​can be monitored for correction and / or mitigation.

[0113] As an example only, in one embodiment, the source current uniformity can be measured by measuring the beam intensity of individual fine beams 211, 212, 213 outside the MEMS element (i.e., outside the condenser lens array and objective lens array). Adjustments can then be made to improve the uniformity of the multiple beams or to compensate for known deficiencies in the uniformity of the multiple beams.

[0114] like [picture] As shown in

[10] , in one embodiment, the device includes at least one movable component. The movable component is configured to move between an operating position and a monitoring position. The operating position corresponds to the operating configuration. The monitoring position corresponds to the monitoring position. [picture]

[10] The movement is indicated by double-ended dashed arrows.

[0115] exist [picture] In the configuration shown in

[10] , the movable component includes a converter 60. An optical detector is associated with the converter. The converter 60 and the optical detector together form a monitoring and detection system. The optical detector is external to the converter and positioned to detect light generated by the converter 60. The converter 60 is configured to move between its operating position corresponding to the operating configuration and its monitoring position corresponding to the monitoring configuration. The operating position is shown above the double-ended arrow. In the operating position, the converter 60 is positioned laterally to the multibeam (e.g., a multibeam device (or pillar)). The converter 60 is positioned to one side of or adjacent to the multibeam. The multibeam passes beside the converter 60 without interacting with the converter 60. The multibeam is projected onto sample 208. [picture]

[10] In this embodiment, the movable component has a different orientation in the operating position compared to the monitoring position. Specifically, in the monitoring position, the converter 60 is substantially perpendicular to the direction of the multi-beam. The converter 60 may be flat. In the operating position, the converter 60 may not be perpendicular to the multi-beam. For example, the converter 60 may be oriented such that the normal to its surface is perpendicular to the multi-beam. By changing the orientation between the operating position and the monitoring position, embodiments of the invention are expected to reduce or minimize the volume occupied by the converter 60. In an alternative configuration, the orientation of the movable component may be the same for both the operating position and the monitoring position. For example, the movable component may move perpendicular to the multi-beam to perform the movement without tilting the movable component. For example, the movable component may slide between the operating position and the monitoring position. This operation can benefit from a simple configuration of actuation between the two positions. This sliding may be linearly actuated. The sliding may be actuated in a rotational manner (such as about an axis away from the sub-beam path). Rotational actuation can reduce or minimize the volume occupied by the converter 60 and its actuation.

[0116] The monitoring location is displayed to the right of the double-ended arrow. For example... [picture] As shown in

[10] , in one embodiment, the monitoring position is located between source 201 and sample 208. In the monitoring position, converter 60 intercepts multiple beams in the countercurrent direction of sample 208. Converter 60 is configured to receive multiple beams output from source 201 and generates light in response to the received multiple beams. Although only converter 60 in the countercurrent direction of the intermediate focal point is depicted, the converter can be positioned in the monitoring position along the sub-beam path from the countercurrent direction of the condenser lens array or the beam-limiting aperture array associated with the condenser lens array to the countercurrent direction of the objective lens array, for example: between the condenser lens array and the intermediate focal point, or between the intermediate focal point and, for example, between the objective lens array and, in the forward direction of one or more electrodes associated with the objective lens array but in the countercurrent direction of the objective lens array. It should be noted that if converter 60 is in the countercurrent direction of the beam-limiting aperture array, the converter will intercept the source beam rather than the multiple sub-beams.

[0117] In one embodiment, the converter 60 includes a scintillator. The converter 60 may include a conversion material, such as YAG. The conversion material may include, for example, a pure crystalline material Y3Al5O12, which may be doped with cerium to form YAG:Ce. The converter 60 may be formed as a YAG screen. In one configuration, the converter includes a single scintillator. In another configuration, the converter includes scintillators for one or more sub-beams in a multi-beam array. In one configuration, the converter includes a plurality of elements for each sub-beam. The scintillator elements may be included in an array, for example, a two-dimensional array, such as an array corresponding to the sub-beams in the multi-beam array.

[0118] like [picture] As shown in

[10] , the movable component is retractable. The converter 60 can be configured to convert multiple beams into light. The light is generated by individual electron beams 211, 212, 213 and can be read out by an optical detector, such as an external camera 61. The optical detector is located remotely from the converter. The optical detector is positioned so that it can detect the light emitted by the converter 60. The optical detector is at least in line of sight of the location of the converter 60 that generates light in response to electrons. In one embodiment, measurements of individual beam profiles can be performed for more detailed information about the source emission properties. This measurement can be performed by: the optical detector, electronics associated with the detector, remote electronics in an electro-optical system such as a remote processing rack, or a processor located somewhere between these two endpoints, such as in an electro-optical device or electro-optical apparatus.

[0119] The converter 60 is expected to have a long lifespan when interacting with high-energy electrons. By providing the converter 60 and external optical detectors such as the camera 61, additional electronic components do not need to be located inside a vacuum. This can help simplify the design of electro-optical devices.

[0120] In one embodiment, at least one movable component includes a light guiding configuration configured to guide light generated by the converter 60 toward an optical detector. In another embodiment, the electro-optical device includes a waveguide configured to guide light from the converter 60 to the optical detector. This makes it possible to read out the generated light via an in-situ optical fiber coupled to an off-site optical detector. Using optical fiber in this manner allows the optical detector to detect the light generated by the converter 60 without the optical detector being in direct line of sight to the converter 60. For example, one or more optical fibers may be provided. This can help reduce the required size of the converter 60 and the optical detector.

[0121] like [picture] As shown in

[10] , in one embodiment, the source 201 and electro-optical elements such as the condenser lens array 231 and the objective lens array can remain stationary when the movable component moves between the operating position and the monitoring position. It is anticipated that one embodiment of the invention will maintain the alignment of the multi-beams.

[0122] [picture]

[11] is a schematic diagram of an exemplary multi-beam electro-optical device according to an embodiment. (The following will not repeat the same information.) [picture] The configuration shown in

[10] has the same features. Unless otherwise mentioned, these common features may be referred to by the same reference numerals and descriptions. [picture] As shown in

[11] , in one embodiment, at least one movable component includes a surveillance detector 64 (or a surveillance detection system). That is, the surveillance detection system is the surveillance detector 64. Therefore, it is not necessary to provide any external optical detector, such as a camera 61.

[0123] In one embodiment, the monitoring detector 64 includes charge detectors, such as a Faraday cup array. Depending on the embodiment, each charged detector, such as a Faraday cup, is configured to measure a separate beam. In an alternative embodiment, the monitoring detector 64 includes a charge-coupled device (CCD). Depending on the embodiment, the monitoring detector may be a semiconductor-based detector, such as a PIN detector. In an alternative embodiment, the monitoring detector 64 includes a direct light detector device and an adjacent optical detector. The direct light detector device includes a transducer configured to generate light in response to charged particles. The adjacent optical detector is configured to directly convert the optical signal generated by the transducer into an electrical signal. The optical detector may be in contact with the transducer.

[0124] This charged detector (such as a Faraday cup array or CCD) or PIN detector can directly detect and read out the electron beam signal without any light conversion step. The direct light detector device is configured to monitor multiple beams without the need for an external camera 61. It is anticipated that one embodiment of the present invention can monitor multiple beams from a vacuum external view converter 60 without the need for an external camera 61. A long service life is anticipated for the direct light detector device.

[0125] In one configuration, the monitoring detector 64 includes monitoring detector elements. In another configuration, the converter includes monitoring detector elements for one or more sub-beams in a multi-beam array. In one configuration, the monitoring detector 64 includes a plurality of elements for each sub-beam. The monitoring detector elements may be contained in an array, for example, a two-dimensional array, such as an array corresponding to the sub-beams in the multi-beam array.

[0126] [picture]

[12] is a schematic diagram of an exemplary multi-beam electro-optical device according to an embodiment. (The following will not repeat the same information.) [picture] The configuration shown in

[10] has the same features. Unless otherwise mentioned, these common features may be referred to by the same reference numerals and descriptions. [picture] As shown in

[12] , in one embodiment, the movable component includes a mirror 62. In a variation, the movable component may be a plurality of individually movable components or a plurality of components configured to move together. The plurality of movable components may together include a mirror, for example, the mirror may be presented as mirror 62. Mirror 62 is configured in a monitoring position to guide light generated by converter 60 toward an optical detector (e.g., external camera 61). Thus, the monitoring and detection system may include converter 60, mirror 62, and optical detector.

[0127] In the monitoring configuration, mirror 62 can be positioned in the downstream direction of converter 60. Mirror 62 can be located between converter 60 and sample 208. Mirror 62 can extend, for example, beyond the path of the sub-beam. The extension can be linear and / or rotational, for example, about an axis spaced apart from the path of the sub-beam. In one embodiment, mirror 62 can move together with converter 60. Mirror 62 and converter 60 can have fixed positions relative to each other. Alternatively, mirror 62 and converter 60 can be configured to move independently of each other. This may be necessary to reduce, for example, the volume required for mirror 62 and converter 60 when they are not in the operating position. Mirror 62 and converter can have fixed positions relative to each other in the monitoring configuration. Mirror 62 and converter can have fixed positions relative to the path of the sub-beam in the monitoring configuration.

[0128] As mentioned above, in one embodiment, the movable component includes (or alternatively, such movable components include) a light guiding configuration. The light guiding configuration is configured to guide light generated by the converter 60 toward an optical detector. The light guiding configuration may include a mirror 62. In one embodiment, the light guiding configuration may include an optical element 63 (e.g., a lens). The optical element 63 is configured to guide light to an optical detector, which may be external to an electro-optical device (or pillar) 41, such as an external camera 61. In one embodiment, the optical element 63 is movable between an operational configuration and a monitoring configuration. In an alternative embodiment, the optical element 63 may remain stationary while the movable component moves. For example, such as... [picture] As shown in

[12] , in one embodiment, the optical element 63 is outside the operating beam path, for example, outside the electron optical column (or device). The optical element 63 does not need to be moved to allow multiple beams to reach the sample 208. If the optical element and the optical detector are stationary between the operating configuration and the monitoring configuration, the volume can be conserved since individual actuators are not required.

[0129] Compared to [picture] In the configuration shown in

[10] , mirror 62 and lens are additional optical components provided to assist in reading the light signal. That is, mirror 62 and optical element 63 improve the transmission of the light signal from converter 60 to an optical detector such as external camera 61. Mirror 62 and optical element 63 can improve detection and / or collection efficiency.

[0130] like [picture] As shown in

[12] , in one embodiment, mirror 62 is tilted relative to converter 60 at an optimal angle, for example. For instance, the mirror may be tilted between 25 and 65 degrees, preferably about 45 degrees. Tilting mirror 62 helps to direct light away from the operating beam path. This allows optical detectors such as external cameras 61 to be positioned outside the operating beam path, such as outside a vacuum.

[0131] In one embodiment, the pitch at the sample point between the fine beams can be approximately 70 µm, for example, between 30 µm and 100 µm. At the sample point, the area occupied by the multiple beams of the sub-beams can be approximately 5, 10, or 15 mm. These dimensions are suitable for multiple beams of sub-beams at any point, for example, around the point collimated by deflector 63 or in the collimation direction of the sub-beams. If the mirror is at 45 degrees, in one embodiment, the mirror 62 is configured such that its height (i.e., its dimension along the direction of the multiple beams) is approximately 15 mm. Alternatively or additionally, the dimension of the mirror in the direction of the multiple beams (i.e., the height dimension in the view shown in the figures) can be controlled by controlling the tilt angle (or orthogonal direction) of the mirror 62 relative to, for example, the direction of the path of the sub-beams. In the depicted configuration, the mirror 62 and the transducer 62 are located in the counter-current direction of the intermediate focal point of each sub-beam and collimator 235. In the countercurrent direction of the central focus 233, the path of the sub-beams diverges and the size (e.g., the width) of the multiple beams is smaller.

[0132] like [picture] As shown in

[12] , in one embodiment, the converter 60, mirror 62, optics 63, and camera 61 are located in the forward direction of the condenser lens array 231. In an alternative embodiment, the converter 60, mirror 62, optics 63, and camera 61 are located in the reverse direction of the condenser lens array 231. This can be advantageous because the size of the mirror will be smaller due to the smaller cross-section of the beam (because it will diverge less). If the condenser lens array 231 is not characterized by a beam-limiting aperture array, the converter 60 and mirror 62 can be located in the forward direction of the beam-limiting aperture array. The converter 60 can interact with the sub-beam. The mirror can be placed between the beam-limiting aperture array and the condenser lens array 231. However, if the converter is in the reverse direction of the beam-limiting aperture array, the converter 60 will interact with the electrons of the source beam 60 (rather than the sub-beam generated from the source beam). Although this may not provide information about the sub-beams, the detection of electrons from the source beam can still provide information about the sub-beams generated from the source beam; the sub-beams exhibit the characteristics of the sub-beams (which are generated from the sub-beams).

[0133] [picture]

[13] is a schematic diagram of an exemplary multi-beam electro-optical device according to an embodiment. The following will not repeat the same information. [picture] The configuration shown in

[12] has the same features. Unless otherwise mentioned, these common features may be referred to by the same reference numerals and descriptions. [picture] As shown in

[13] , the mirror 62 and / or converter 60 being retractable is not essential. In one embodiment, the device includes: a converter 60 positioned in the path of the multi-beam to generate a beam in response to the multi-beam; and a mirror 62 configured in a monitoring configuration to guide the beam to a detector (ideally in the monitoring configuration).

[0134] The converter 60 can remain in the same position both in the operational configuration and in the monitoring location. By having fewer moving parts, reliability can be improved and / or the space occupied by the device can be reduced. One embodiment of the invention is expected to reduce the overall size required by the components used for performing multi-beam monitoring.

[0135] like [picture] As shown in

[13] , in one embodiment, a plurality of apertures 65 are defined in the converter 60 for the paths of multiple beams to pass through. When the electro-optics is in an operational configuration, the apertures 65 allow narrow beams to pass through.

[0136] like [picture] As shown in

[13] , in one embodiment, a plurality of openings 56 (or apertures) are defined in mirror 62. The openings 56 are configured to allow sub-beams of a multi-beam array to pass through mirror 62 toward sample 208. When the electro-optics is in an operational configuration, the openings 56 allow narrow beams to pass through. Mirror 62 is configured to reflect light toward an optical detector (e.g., external camera 61). In an operational configuration, the paths of the plurality of beams of a multi-beam array pass through individual openings 56 defined in mirror 62.

[0137] like [picture] As shown in

[13] , in the monitoring configuration, the paths of a plurality of beams in the multi-beam configuration are incident on the converter 60. The paths of the sub-beams in the operating configuration are different from those in the monitoring configuration. In one embodiment, the device includes deflectors, or a plurality of deflectors operable between a detection setting corresponding to the operating configuration and a measurement setting corresponding to the monitoring configuration.

[0138] For example, such as [picture] As shown in

[13] , in one embodiment, the electronics include a switching deflector array 78. The switching deflector array 78 includes a plurality of deflectors configured to switch between an operating configuration and a monitoring configuration. Each deflector of the switching deflector array 78 can be configured to act on a separate sub-beam path.

[0139] The deflectors of the switching deflector array 78 are configured to control the direction of the sub-beams in the downstream direction of the condenser lens array 231. The switching deflector array can be located in the downstream direction of the condenser lens array 231. The switching deflector array 78 is located in the upstream direction of the converter 60.

[0140] In the operational configuration, the switching deflector array 78 is configured to guide the sub-beams through the converter 60 and the aperture 65 in the mirror 62. In the monitoring configuration, the switching deflector array 78 is configured to guide the sub-beams along switching beam paths 66, 67, and 68 to incident on the converter 60. In one embodiment, a controller is configured to control the potential applied to the electrodes of the switching deflector array 78 to control the switching of electronics between the operational and monitoring configurations.

[0141] exist [picture] In the configuration shown in

[13] , the switching deflector 78 includes a plurality of deflector elements to operate on paths in the individual beam paths of the multi-beam array. In an alternative embodiment, the switching deflector 78 includes a provided mega-deflector configured to operate on all beam paths of the multi-beam array. When the mega-deflector is provided, the switching deflector array may be omitted. Alternatively, the switching deflector array may have intermediate switching deflectors, each deflector operable on a group of sub-beams in the multi-beam array with respect to the intermediate switching deflector.

[0142] Reference [picture]

[13] In one variation of the configuration depicted and described, the converter 60 may be as referenced [picture]

[11] as shown and referenced [picture]

[11] The described embodiment replaces the monitoring detector 64 described herein. (That is, the monitoring detection system includes the monitoring detector 64). For example, the monitoring detector may include detector elements such as charged detectors (e.g., Faraday cups or charge-coupled devices), PIN detectors, and / or direct light detector devices. Having a monitoring detector 64 instead of a converter 60 means that optical elements such as mirror 62, lenses, and optical detectors 61 are not required. This reduces the size required for the monitoring system. Furthermore, the aperture 65 and the switching deflector 78 allow the monitoring detector 64 to be maintained in the appropriate position in the operational configuration and in the monitoring configuration.

[0143] [picture]

[14] is a schematic diagram of an exemplary multi-beam electro-optical device according to an embodiment. (The following will not repeat the same information.) [picture] The configuration shown in

[10] has the same features. Unless otherwise mentioned, these common features may be referred to by the same reference numerals and descriptions. [picture] As shown in

[14] , in one embodiment, at least one movable component includes one of a source 201 and an objective array. The objective array is configured in an operational configuration to project multiple beams onto a sample 208. [picture]

[14] Display the electronic devices in the monitoring configuration. In the operation configuration, the characteristics of the electro-optical devices will be as follows: [picture] As shown in [3], the converter 60 and the optical detector 61 are positioned to the side of the electronic device or the pillar 41. Therefore, the monitoring and detection system includes the converter 60 and the optical detector 61.

[0144] The electronic device may include a source module 69. The source module 69 includes a source 201. For example... [picture] As shown in

[14] , in one embodiment, the source module 69 includes a condenser lens array 231. The electronics 41 may further include an objective lens array, which may be in the downstream direction or part of the objective lens module 70. The electronics are configured such that the source module 69 and the objective lens module 70 are movable relative to each other. In one embodiment, the source module 69 is configured to move, for example, between an operating configuration and a monitoring configuration while the objective lens module 70 remains stationary. In an alternative embodiment, the objective lens module 70 is configured to move, for example, between an operating configuration and a monitoring configuration while the source module 69 remains stationary. In another alternative embodiment, both the objective lens module 70 and the source module 69 are configured to move between an operating position and a monitoring position in their respective configurations.

[0145] like [picture] As shown in [3], in one embodiment, in the operational configuration, the multibeams are aligned with the lens 234 of the objective array 70. [picture] As shown in

[14] , in one embodiment, in a monitoring configuration, the multiple beams are offset from the objective array 70. In one embodiment, the electro-optics device includes an actuator (not shown). The actuator is configured to actuate the electro-optics device between an operating configuration and a monitoring configuration. The actuator can be configured to operate linearly or rotatably about an axis remote from the path of the sub-beams, ideally with the axis parallel to the path of the sub-beams.

[0146] The source module 69 or the objective lens module 70 can be configured to move laterally. For example, such as [picture] As shown in

[14] , in one embodiment, source module 69 is configured to move laterally such that the multiple beams are aligned with converter 60 in a monitoring configuration. Converter 60 is configured to convert the electron beams into light. The light can be detected by an optical detector such as camera 61. Once monitoring is complete, source module 69 can be moved to align the multiple beams with objective lens module 70; that is, source module 69 moves relative to objective lens module 70 (e.g., objective lens array 234). Although referenced... [picture]

[14] Described and shown in [picture]

[14] The embodiment has an actuable source module, but in a different configuration, it is an objective module that can be actuated by a converter 60 so that the converter 60 replaces the objective module 70 in the downstream direction of the source module 69.

[0147] When the source module 69 is aligned with the converter, it is easier to determine the properties of the source 201. For example... [picture] As shown in

[14] , in one embodiment, source module 69 includes a condenser lens array 231. This allows source module 69 to perform simple lateral movement to switch between monitoring and operating configurations. Having the condenser lens array 231 or at least a beam-limiting aperture array included in source module 69 allows monitoring of sub-beams and their properties. Although a division is shown between source module 69 and objective module 70 in the countercurrent direction of the intermediate focal point of the sub-beam, this division can be at any point in the forward direction of the condenser lens array 231. For example, the division can be in the forward direction of the collimator array 235, for example in the forward direction of one or more electrodes associated with objective array 234, and for example above the electrodes of the objective array.

[0148] In an alternative embodiment, source module 69 does not include condenser lens array 231. The condenser lens array may have a fixed position relative to objective lens array 70. Source 201 may be movable relative to condenser lens array 231 and objective lens array 70. In the monitoring configuration, source beam 202 is incident on transducer 60. This allows for more accurate determination of source properties. For example, any influence of the aperture of condenser lens array 231 on the measuring beam can be avoided. Since sub-beams are generated by source beam 202, some properties and characteristics of the source beam will also exist in the sub-beams. Therefore, monitoring source beam 202 effectively monitors one or more properties of the sub-beams.

[0149] [picture]

[15] is a schematic diagram of an exemplary multi-beam electro-optical device according to an embodiment. (The following will not repeat the same information.) [picture] The configuration shown in

[14] has the same features. Unless otherwise mentioned, these common features may be referred to by the same reference numerals and descriptions. [picture] As shown in

[15] , in one embodiment, the converter 60 (and, where appropriate, the optical detector 61) is replaced by a monitoring detector 64. In this embodiment, the monitoring detection system includes the monitoring detector 64.

[0150] In one embodiment, the monitoring detector 64 includes a charge detector, such as a Faraday cup array. Depending on the embodiment, each Faraday cup is configured to measure a separate beam. In an alternative embodiment, the monitoring detector 64 includes a charge detector, such as a charge-coupled device (CCD). In an alternative embodiment, the monitoring detector 64 includes a direct light detector device comprising: a transducer configured to generate light in response to charged particles; and an adjacent optical detector configured to directly convert the light signal generated by the transducer into an electrical signal. The optical detector may be in contact with the transducer, for example, in direct contact.

[0151] [picture]

[16] is a schematic diagram of an exemplary multi-beam electro-optical device according to one embodiment. The electro-optical device is configured to project multiple beams of electrons. The electro-optical device may be configured as described in any of the embodiments described above. Unless otherwise mentioned, such common features may be referred to by the same reference numerals and descriptions. [picture] The configuration shown in

[16] may include the following: [picture] [3] shows the same configuration features, but does not show the countercurrent direction of the objective array 234 (which may include control lens array 250) and / or additional electrodes associated with the objective array 234. In one embodiment, [picture] The electro-optical device shown in

[16] includes a control lens array and, where appropriate, additional and associated electrodes in the countercurrent direction of the objective array 234, as described above. In other embodiments, the electro-optical device is similar to another of the configurations described above, such as a configuration including a giant scan deflector instead of a scan deflector array 260. In other embodiments, the electro-optical device includes features of another of the configurations described above, such as [picture] [8] and [picture] The configuration shown in [9].

[0152] like [picture] As shown in

[16] , in one embodiment, the electro-optical device includes a source 201 configured to output a source beam 202 for generating multiple beams. [picture] As shown in

[16] , in one embodiment, the electro-optical device includes an aperture array. The aperture array is configured to form a plurality of beams from the source beam 202 by blocking a proportion of the projection of the source beam 202 toward the sample 208. This aperture array may be referred to as a beam-limiting aperture array. In one embodiment, the aperture array is included in a condenser lens array 231. In another configuration, the aperture array is located in the countercurrent direction of the condenser lens array 231.

[0153] like [picture] As shown in

[16] , in one embodiment, the electro-optical device includes a detector (or monitoring detection system) configured to measure at least one parameter of at least a portion of the blocked proportion of the source beam 202. In one embodiment, the monitoring detection system includes an optical detector and a converter 60. The optical detector may include a camera 61. The camera is configured to detect light. In one embodiment, the converter 60 is provided to convert the source beam 202 into light detectable by the optical detector.

[0154] like [picture] As shown in

[16] , in one embodiment, the converter 60 is located on the counter-current surface of an aperture array, which may be a beam-limiting aperture array. In one embodiment, the received source beam 202 includes at least a portion of the proportion of the source beam 202 blocked by the aperture array. It is contemplated that one embodiment of the invention allows monitoring of the source beam 202 without significantly affecting the multiple beams incident on the sample 208. The source beam 202 may be monitored online, for example, during detection or measurement procedures, using a monitoring detector.

[0155] like [picture] As shown in

[16] , in one embodiment, the converter 60 includes a coating 71. The coating 71 may be in the form of a plurality of individual segments, for example, in the form of an array. Each element array may be associated with one or more of the apertures in the array. Alternatively, the coating 71 may be continuous. The coating 71 is disposed between the apertures of the aperture array (which may be a portion of the condenser lens array 231). The coating 71 may contain, for example, a YAG-containing material as described above.

[0156] In one embodiment, camera 61 is configured to read out the generated light by means of displacement (e.g., outside a column of a vacuum chamber such as an electro-optical device). [picture] As shown in

[16] , in one embodiment, the camera 61 and the converter 60 are configured such that the camera 61 has a direct view of the converter 60. The converter is in the direct line of sight of the optical detector. In one embodiment, light is directly detected.

[0157] [picture]

[17] is a schematic diagram of an exemplary multi-beam electro-optical device according to an embodiment. These common features can be employed [picture]

[16] uses the same reference number and description. This will not be repeated below. [picture] The configuration shown in

[16] has the same characteristics. For example, [picture] As shown in

[17] , in one embodiment, the electro-optical device includes a light-reflecting element, such as a mirror 72. The mirror 72 is configured to reflect light generated by the converter 60 toward an optical detector. In this embodiment, the monitoring and detection system includes the converter 60, the mirror 72, and the light detector.

[0158] like [picture] As shown in

[17] , in one embodiment, mirror 72 is positioned around source 201. Mirror 72 is configured to reflect light to a location most convenient for placing the detector. It is anticipated that one embodiment of the invention will allow monitoring of source beam 202 without making the manufacturing apparatus significantly more mechanically difficult or complex.

[0159] like [picture] As shown in

[17] , in one embodiment, mirror 72 is positioned in the countercurrent direction of converter 60. In one embodiment, mirror 72 is located between converter 60 and source 201. Mirror 72 may be located in a volume that will be relatively empty. It is contemplated that one embodiment of the invention will allow monitoring of source beam 202 without significantly affecting the mechanical design of parts of the apparatus used during detection or metrology procedures.

[0160] like [picture] As shown in

[17] , in one embodiment, mirror 72 includes aperture 73. Aperture 73 can be used to accommodate source 201, such as [picture] As shown in

[17] . Alternatively, aperture 73 may be used to accommodate source beam 202. The mirror may be located in the downstream direction of source 201.

[0161] Generally, mirror 72 is positioned relative to the optical detector and transducer 60 such that the optical detector detects light generated at least in a selected area (e.g., all) of the surface of transducer 60. Mirror 72 does not need to be placed around source 201, but is placed to one side of the source and / or in the opposite direction to or (if mentioned) in the same direction as the source 201. Ideally, the optical detector is positioned in the straight path of light from transducer 60 as it is reflected from mirror 72. Mirror 72 may be curved or have more than one surface, for example, it may be in the form of a Fresnel mirror, as long as the light emitted from transducer 60 reaches the optical detector.

[0162] In one embodiment, [picture] The converter 60 and camera 61 shown in

[16] can be replaced by a monitoring detector, such as a Faraday cup array or a CCD, which can be arranged in an array, for example, for one or more detectors for each aperture in a beam-limiting aperture array, for example, around one or more apertures of the beam-limiting aperture array. (Therefore, the monitoring detection system is characterized by monitoring detectors, rather than, for example, converter 60, optical detectors, and mirror 72). The device can operate at a low current from the electron source 201 in order to reduce the effects of undesirably charged Faraday cups or CCDs that may undesirably affect multiple beams.

[0163] [picture]

[18] A schematic diagram illustrating a portion of an electro-optical device comprising a plurality of converters 410 and a light guiding configuration. (This will not be repeated below.) [picture] The device features the same configuration as shown in [8]. The device includes electronic components (or pillars) and a photosensor assembly.

[0164] In all and each of the configurations shown and described with respect to Figures 10 through 17, and in the mentioned and derived embodiments, the monitoring and detection system can generate detection signals. The detection signals generated by the optical detector 75 can be used by the controller 50 or an element of the controller to control an element or assembly of the electro-optics (or pillars) 41. The detection signals may contain information about the relative positions of the sub-beams within the multi-beam configuration (such as the relative alignment of the sub-beams at the converter 60 or monitoring detector 64). The detection signals can be used by the controller or an element of the controller, for example, by controlling one or more correctors of the electro-optics 41 to align the sub-beams. The invention is primarily described herein for the purpose of monitoring the sub-beams of a multi-beam configuration for the purpose of correcting alignment between sub-beams and between electro-optical components (even electro-optical elements) along the path of the multi-beam configuration. Alternatively, the invention can be used to monitor other types of characteristics, such as aberrations, for correction or adjustment. Alternatively, the sub-beams of a multi-beam configuration can be measured for one or more of the following: focusing aberrations, characteristics or even aberrations in source beam uniformity, and off-axis aberrations such as field curvature, distortion, and astigmatism. Correctors in the electro-optical device can be controlled to correct or at least reduce the magnitude of one or more of these characteristics or aberrations.

[0165] like [picture] As shown in

[18] , in one embodiment, the electronic device includes an array of objectives 403 configured to project multiple beams onto a portion of the sample 208. In one embodiment, the electronic device includes a plurality of transducers 410 configured to receive signal electrons emitted from the sample 208 and to generate light in response to received signal particles. The transducers 410 may be scintillators. The transducers 410 may contain a conversion material as described above with respect to the material of transducer 60.

[0166] In another configuration, the objective array 403 may additionally or alternatively be associated with another plate, such as an electrode, which is a lens electrode, such as one associated with an objective integrated into the objective array or also close to the countercurrent direction of an objective, such as a control lens array. In one configuration, additionally or alternatively, the detector array is located in the countercurrent direction of the objective array and any electro-optical elements associated with the objectives. The detector elements of the detector array may be associated with individual sub-beams. The detector elements may include charge detection, scintillators, and PIN detection elements. In a configuration where the detector elements include scintillators, the detectors may be positioned on one side of the sub-beam path such that the sub-beams are delivered to that side of the individual detector elements.

[0167] A deflection element may be positioned between the detector array and the objective lens, such as a Wien filter, for example, a Wien filter array. Such a Wien filter allows the sub-beams to pass through the Wien filter undeflected toward the sample, but directs signal particles from the sample toward the detector elements. An optical transducer (e.g., an optical detector) may be positioned to convert the light generated by the scintillator into an electronic signal. The optical transducer may be coplanar with and even in direct contact with the scintillator elements. Such optical transducers are described in European Patent Application No. 21183803.2, filed July 5, 2021, which relates at least to the architecture and use of optical transducers associated with scintillators and detectors for detecting signal particles, and is incorporated herein by reference.

[0168] like [picture] As shown in

[18] , in one embodiment, the electronic device includes a light guiding configuration that includes a mirror 414. In the mirror 414, a plurality of apertures 416 are defined that allow multiple beams to pass through the mirror 414 toward the sample 208.

[0169] The light guiding configuration is set to guide the light 411 generated by the converter 410 to the photosensing assembly. For example... [picture] As shown in

[18] , in one embodiment, the light sensing assembly includes an evaluation sensor (e.g., light sensor 412) and an optical detector 75, each configured to detect light 411 generated by converter 410. For example, the evaluation sensor is configured to detect light 411 during a detection or measurement procedure. In practice, the evaluation sensor is part of an evaluation system for detecting signal particles. For example, the evaluation sensor is functionally equivalent to... [picture] [3] Detector 240. Optical detector 75 is a part configured to improve, for example, detection or measurement procedures.

[0170] like [picture] As shown in

[18] , in one embodiment, the photosensing assembly includes a beam splitter 77 configured to split the light 411 generated by the converter 410 into beams directed toward an evaluation sensor and toward a detector 75. Both the photosensor 412 and the detector 75 can be configured to simultaneously detect different portions of the light 411. [picture] As shown in

[18] , in one embodiment, the photosensing assembly includes an optical element 76, such as a lens. The optical element 76 is configured to act on light 411 directed toward the detector 75. For example, the optical element 76 can focus light onto the detector 75.

[0171] In one embodiment, the device includes a controller configured to match the detection signal of an evaluation sensor to a portion of the multi-beam projection onto sample 208 based on the detection signal of optical sensor 75. For example, a photosensor 412 may be used in a sensor array, for which different portions of the beam from converter 410 associated with signal particles generated by different sub-beams need to be aligned with corresponding portions of photosensor 412 (such as sensor elements of the sensor array). Monitoring by optical sensor 75 can be used to calibrate and / or improve the accuracy of the signal detected by photosensor 412. Optical sensor 75 can be used to monitor the alignment of the multi-beam, such as the position of different portions of the beam relative to optical sensor 75 and its detection elements. The position of the detection elements of optical sensor 75 can be calibrated by the different portions of photosensor 412 (e.g., sensor elements). The signals detected by the optical detector 75 (e.g., detection signals) can be used in subsequent or ongoing procedures to improve the alignment of the multi-beams. The signals detected by the optical detector 75 can be used to control components of the photosensing assembly, such as mirror 414 and / or optics 418, which may include lenses. The components of the photosensing assembly can be controlled by a controller based on the detection signals to improve the alignment of the light from the converter 410, resulting in better alignment of its different parts with portions of the photosensor 412 (e.g., sensor elements). Detection signals transmitted from the data line 422 more accurately distinguish between signal particles generated by each sub-beam.

[0172] [picture]

[19] is a schematic diagram of an exemplary multi-beam device according to one embodiment. [picture] As shown in

[19] , in one embodiment, the electronic device 41 includes a monitoring component 190. The monitoring component 190 is located in the monitored beam path. In one embodiment, the monitoring component 190 is in the countercurrent direction to the detector (e.g., a monitoring detection system). In one embodiment, the monitoring component 190 is used to monitor (e.g., detect) the size of one or more of a plurality of beams. The monitoring component 190 can be used to measure the size of one or more electronic beams.

[0173] [picture]

[20] is a schematic close-up view of the monitoring component 190. [picture]

[20] Showing one of the multiple beams 212 passing through the monitoring component 190. For example... [picture] As shown in

[20] , in one embodiment, the monitoring component 190 includes an array of blocking elements 194. The blocking elements 194 are configured to block sub-beams in a multi-beam configuration. For example, a portion of sub-beam 212 may be blocked by the blocking elements 194.

[0174] [picture]

[20] A converter 60 is shown as part of a detector. The detector may further include a camera. Alternatively, the detector may be another component configured to detect changes in current. In one embodiment, the detector is a direct electronic detector, such as a PIN detector or a current detector. []

[0175] [picture]

[21] is a schematic plan view of the monitoring component 190. [picture]

[21] Ten blocking elements 194 configured as part of a monitoring component 190 are schematically shown. The monitoring component 190 may contain hundreds or thousands of blocking elements 194 in an array of blocking elements 194.

[0176] like [picture] As shown in

[21] , in one embodiment, the blocking element 194 has a similar pattern. For example, as [picture] As shown in

[21] , in one embodiment, the blocking element 194 has an annular pattern. Each blocking element 194 may be annular in shape. The annular shape has the advantage of a particularly simple structure.

[0177] [picture]

[22] A schematic close-up view of one of the blocking elements 194 of the monitoring component 190. For example... [picture] As shown in

[22] , in one embodiment, the blocking element 194 has an inner edge 197. In one embodiment, the inner edge 197 of the blocking element 194 forms a knife edge (i.e., a distinct edge, a sharp edge). In one embodiment, the blocking element 194 (and specifically, the inner edge 197 of the blocking element 194) forms a knife edge pattern. The knife edge pattern enables the measurement of the maximum size of the spot formed by the sub-beams 212. In one embodiment, the controller is configured to control the electronics 41 to scan the multi-beams relative to the knife edge pattern. This may be referred to as knife edge scanning.

[0178] like [picture] As shown in

[22] , in one embodiment, the monitoring component 190 includes an array of apertures 193. The array of apertures 193 is adjacent to individual blocking elements 194. The array of apertures 193 is used for multiple beams to pass through it. For example, such as [picture] As shown in

[20] , the sub-beam 212 can pass through the aperture 193. For example... [picture]

[20] [to] [picture] As shown in

[22] , in one embodiment, individual apertures 193 of the aperture array correspond to individual blocking elements 194 of the array of blocking elements 194. In one embodiment, the number of blocking elements 194 is equal to the number of apertures 193. Alternatively, the number of blocking elements 194 may be greater than the number of apertures 193.

[0179] like [picture] As shown in

[21] , in one embodiment, individual blocking elements 194 surround individual apertures 193. For example, as mentioned above, in one embodiment, the individual blocking elements 194 are annular. In one embodiment, the blocking elements 194 are concentric with the individual apertures 193. Alternatively, the center of the blocking element 194 may be offset from the center of the aperture 193.

[0180] It is not necessary for the blocking element 194 to be annular. In one embodiment, each blocking element 194 comprises a plurality of portions spaced apart from each other. A portion of the blocking element 194 may be spaced apart from the aperture 193 associated with the blocking element 194. The blocking element 194 may be linear, square, or another shape. A square or other shape may surround the aperture 193. However, it is not necessary for the blocking element 194 to surround the aperture 193.

[0181] In one embodiment, the blocking element 194 comprises a material that blocks electrons from multiple beams. For example, in one embodiment, the blocking element 194 comprises one or more of tungsten, gold, and iron. In one embodiment, the blocking element 194 comprises an element having at least as many atoms as iron.

[0182] like [picture]

[22] As most clearly shown, in one embodiment, the inner edge 197 of the blocking element 194 is spaced apart from the rim 195 of each individual aperture 193. When scanning the sub-beams 212 of a multi-beam array over the blocking element 194 of the monitoring assembly 190, a detector (e.g., a monitoring detection system) can be configured to detect changes in the size of the sub-beams 212 reaching the detector. The rate of change can indicate the size of the sub-beams 212.

[0183] like [picture] As shown in

[19] , in one embodiment, the monitoring component 190 is positioned close to the plane of the intermediate focus 233. In one embodiment, the monitoring component 190 is in the downstream direction of the intermediate focus 233. For example, as [picture] As shown in

[19] , in one embodiment, the electronics 41 includes a deflector 235 at a central focal point 233. In one embodiment, the deflector 235 is configured to scan sub-beams 211 to 213 of the multi-beam array over the monitoring component 190. The monitoring component 190 may be located in the downstream direction of the deflector 235.

[0184] When the electronics 41 is in an operational configuration, the deflector 235 can be controlled to allow sub-beams 211 to 213 to pass through the aperture 193 of the monitoring assembly 190. When the electronics 41 switches to a monitoring configuration, the deflector 235 can be controlled to allow sub-beams 211 to 213 of the multiple beams to scan over the inner edge 197 of the blocking element 194 of the monitoring assembly 190. In one embodiment, the monitoring assembly 190 includes blades for each sub-beam. Relatively small deflections are required to scan the sub-beams over the inner edge 197 of the blocking element 194. By providing the aperture 193, the monitoring assembly 190 can remain in place during both the monitoring and operational configurations.

[0185] like [picture] As shown in

[20] , in one embodiment, the monitoring component 190 includes a substrate having a thicker region 191 and a thinner region 192. The substrate may contain, for example, silicon. The thicker region 191 is thicker than the thinner region 192. In one embodiment, the thickness of the thicker region 191 (in the direction of the multi-beam) is at least 100 µm, at least 200 µm, and at least 500 µm. In one embodiment, the thickness of the thicker region 191 is at most 1 mm and at most 500 µm. In one embodiment, the thickness of the thinner region 192 is at least 100 nm, at least 200 nm, at least 500 nm, and at least 1 µm. In one embodiment, the thickness of the thinner region is at most 10 µm, at most 5 µm, at most 2 µm, and at most 1 µm.

[0186] like [picture] As shown in

[20] , in one embodiment, the blocking element 194 is disposed on a thinner region 192 of the substrate. As mentioned above, in one embodiment, the inner edge 197 of the blocking element 194 is spaced apart from the rim 195 of each individual aperture 193. In one embodiment, the thinner region 192 of the substrate includes an uncovered region 196, such as... [picture]

[22] is shown most clearly. The uncovered area 196 is located between the blocking element 194 and the aperture 193. In a plan view (i.e., when viewed in a direction parallel to the electron optical axis), the uncovered area 196 is located between the inner edge 197 of the blocking element 194 and the rim 195 of the aperture 193. The detector is configured to detect changes when the sub-beam 212 is scanned over the knife-edge pattern. The detector can be configured to detect changes when the sub-beam 212 passes through the aperture 193, when the sub-beam 212 is over the uncovered area 196, and when the sub-beam 212 is over the blocking element 194.

[0187] In one embodiment, the thickness of the blocking element 194 is at least 10 nm, possibly at least 20 nm, possibly at least 50 nm, possibly at least 100 nm, and possibly at least 200 nm. In another embodiment, the thickness of the blocking element 194 is at most 1 µm, possibly at most 500 nm, and possibly at most 200 nm. By providing a thicker blocking element 194, the contrast at the detector between the sub-beam 212 above the blocking element 194 and the sub-beam passing through the thinner region 192 of the substrate can be increased.

[0188] In one embodiment, the size (e.g., diameter) of aperture 193 is at least 500 nm, at least 1 µm, at least 2 µm, at least 5 µm, and at least 10 µm. In one embodiment, the size (e.g., diameter) of aperture 193 is at most 100 µm, at most 50 µm, at most 20 µm, and at most 10 µm. In one embodiment, the size (e.g., diameter) of the thinner region 192 corresponding to each aperture 193 is at least 2 µm, at least 5 µm, at least 10 µm, at least 50 µm, and at least 100 µm. In one embodiment, the size (e.g., diameter) of the thinner region 192 is at most 1 mm, at most 500 µm, at most 200 µm, at most 100 µm, and at most 50 µm.

[0189] like [picture] As shown in

[19] , in one embodiment, the detector is spaced a distance from the monitoring component 190 along the path of the monitoring beam. [picture] As shown in

[19] , in one embodiment, at least one electro-optical component is located between the monitoring component 190 and the detector. For example, in one embodiment, at least one of the array of scanning deflectors 260, the array of objectives 234, and the electronic detection device 240 is located between the monitoring component 190 and the monitoring and detection system. In one embodiment, one or more other electro-optical components are located between the monitoring component 190 and the monitoring and detection system. For example, the control lens array 250 (e.g., [picture] [3] (shown in the figure) can be located between the monitoring component 190 and the monitoring detection system.

[0190] The embodiment of electronic device 41 includes at least one deflector 235. Deflector 235 is operable between a detection setting corresponding to an operating configuration and a measurement setting corresponding to a monitoring configuration. In the detection setting, deflector 235 is configured to guide sub-beams 211 to 213 through aperture 193. In the measurement setting, deflector 235 is configured to scan sub-beams 211 to 213 over a knife-edge pattern (e.g., over the inner edge 197 of the blocking element 194). In the measurement setting, at least one deflector 253 is configured to scan multiple beams over a portion of the monitoring component 190. In one embodiment, at least one deflector 235 is configured to scan multiple beams such that sub-beams 212 are scanned over features of individual blocking elements 194. For example, sub-beams can be scanned over the knife edges of individual blocking elements 194.

[0191] like [picture] As shown in

[19] , in one embodiment, the detector is in the direction of the electron optical element that is most downstream of the electronic device 41. For example, as [picture] As shown in

[19] , in one embodiment, the electron optical element in the most downstream direction of the electronic device 41 is an electron detection device 240. The electron detection device 240 is used to detect electrons when the electronic device 41 is in an operating configuration. The detector used to monitor the configuration is in the downstream direction of the electron detection device 240.

[0192] In one embodiment, the detector is positioned at least 500 µm, possibly at least 1 mm, possibly at least 2 mm, and possibly at least 5 mm away from the monitoring component 190 in the downstream direction. By positioning the detector away from the monitoring component 190, electrons scattered and emitted from the blocking element 194 can be geometrically more easily separated from directly transported electrons. This geometric separation makes it easier for the detector to distinguish which electrons are transported through the thinner region 192 of the substrate and which electrons are scattered in the knife-edge pattern. One embodiment of the invention is expected to increase measurement accuracy. One embodiment of the invention is expected to increase the dimensional tolerances of the knife-edge pattern.

[0193] like [picture] As shown in

[19] and described above, in one embodiment, the detector includes a converter 60 and an optical detector, such as a camera 61. [picture] The converter 60 and optical detectors such as camera 61 shown in

[19] may have, for example, those described above. [picture]

[10] Features that are the same as those described. For example [picture] As shown in

[19] , in one embodiment, the detector may be located at the position of sample 208. The detector may be positioned at a distance from the monitoring component 190 as a sample. The detector may be supported by a support or stage that may also support a sample holder. The converter 60 and the optical detector may be included in the stage. When the electronics 41 is in an operational configuration, sample 208 may be located in the sample position. When the electronics 41 is switched to a monitoring configuration, sample 208 may be switched by the converter 60. In one embodiment, the stage 209 is configured to move sample 208 and converter 60.

[0194] [picture]

[23] is a schematic diagram of an exemplary multi-beam device according to one embodiment. [picture] The device shown in

[23] may have the same characteristics as described above. [picture]

[22] The same features are described, but the differences are as follows. For example, [picture] As shown in

[23] , in one embodiment, the detector includes a monitoring detector 64. The monitoring detector 64 may, for example, be relative to the above description. [picture]

[11] As described. By way of example only, the monitoring detector 64 may include one or more Faraday cups and / or more PIN detectors. Alternatively or additionally, other types of detectors may be used. Unless stated to the contrary, [picture] The features of the monitoring detector 64 of

[11] are applicable to [picture]

[23] Monitoring and detection device 64.

[0195] [picture]

[24] is a schematic diagram of an exemplary device according to one embodiment. For example, [picture] The device shown in

[24] may have the same characteristics as described above. [picture]

[19] describes the same features. [picture] As shown in

[24] , in one embodiment, the detector is associated with an objective lens assembly of electronics 41. The objective lens assembly includes an array of objective lenses 234. The objective lenses 234 are configured to direct multiple beams onto the sample 208. [picture] In the embodiment shown in

[24] , the detector includes a monitoring detector 64. The detector can be kept in place for both the operational configuration and monitoring configuration of the electronics 41. Unless stated to the contrary, the features of the monitoring detector 64 of FIG11 are applicable to... [picture]

[24] Monitoring and detection device 64.

[0196] In one embodiment, the detector is a portion of the same stack as objective lens 234. For example... [picture] As shown in

[24] , in one embodiment, the detector is located at the countercurrent end of the objective lens assembly. The detector is spaced apart from the monitoring component 190.

[0197] [picture]

[25] for [picture] A schematic diagram of the detector shown in

[24] . [picture] As shown in

[25] , in one embodiment, the detector includes a detector substrate 642 in which an array of apertures 643 is formed. In one embodiment, the detector includes an array of detection elements 641. In one embodiment, the detection elements 641 correspond to individual apertures 643.

[0198] In one embodiment, detection element 641 surrounds individual apertures 643. In an operational configuration, multiple beams pass through aperture 643. In a monitoring configuration, deflector 235 is configured to guide sub-beams to scan over a knife-edge pattern. Electrons can be detected by detection element 641.

[0199] Detection element 641 may include charge detection, scintillator, and PIN detection elements. For example, detection element 641 may include one or more Faraday cups or CCDs. In one embodiment, detection element 641 is configured to convert electrons into photons that can be detected by an optical detector such as a camera. []

[0200] Multi-beam electro-optical devices may include a gun aperture plate or a Coulomb aperture array (not shown). The gun aperture plate is the plate that defines the aperture. It is located in the electro-optical device in the downstream direction of the source and before any other electro-optical device. [picture] [3] In this configuration, it will be located between source 201 and condenser lens array 231. In operation, the gun aperture plate is configured to block peripheral electrons of the source beam 202 to reduce the Coulomb effect in the beam before the beam splitter (e.g., in or associated with the condenser lens array). However, the gun aperture array may have fewer apertures than the condenser lens array, and the number of apertures may be less than the number of fine beams in the downstream direction of multiple beams. Since the gun aperture array is a type of aperture array and is spaced apart from other beam-limiting aperture arrays such as condenser lens arrays and objective lens arrays, it can also be considered in the alignment process.

[0201] A multi-beam electro-optical device may contain a plurality of electro-optical components. A multi-beam electro-optical device may be a multi-column device.

[0202] The terms "sub-beam" and "splitter" are used interchangeably herein and are both understood to encompass any beam of radiation derived from the parent beam by dividing or splitting the parent beam. The term "manipulator" is used to encompass any element that affects the path of a sub-beam or splitter, such as a lens or deflector.

[0203] References to top and bottom, upper and lower, lowest, upward and downward, and above and below should be understood as referring to directions parallel to the (usually but not always vertical) countercurrent and downstream directions of the electron beam or multiple beams impacting sample 208. Therefore, references to the countercurrent and downstream directions are intended to refer to directions independent of any current gravitational field relative to the beam path.

[0204] References to elements aligned along the beam path or sub-beam path should be understood to mean that individual elements are positioned along the beam path or sub-beam path.

[0205] An evaluation tool according to one embodiment of the present invention may be a tool for performing qualitative evaluation of a sample (e.g., pass / fail), a tool for performing quantitative measurement of a sample (e.g., feature size), or a tool for generating an image of a sample. Examples of evaluation tools are inspection tools (e.g., for identifying defects), inspection tools (e.g., for classifying defects), and metrology tools, or any combination of tools capable of performing evaluation functionality associated with an inspection tool, inspection tool, or metrology tool (e.g., metrology testing tool). Electro-optical device 40 (which may include an electron optical column) may be a component of the evaluation tool; such as an inspection tool or metrology testing tool, or part of an electron beam lithography tool. Any reference to tools herein is intended to cover devices, apparatuses, or systems that include various components that may be co-located or non-co-located and may even be located in a separate location, particularly for example, for data processing elements.

[0206] A reference to charged particle optics can be more specifically defined as a charged particle optical column. In other words, the device can be provided as a column. Therefore, a column can include an objective array assembly as described above. A column can thus include a charged particle optical system as described above, such as including an objective array and, depending on the situation, a detector array and / or, depending on the situation, a condenser lens array. Depending on the situation, the charged particle device may include a source. The charged particle device may be included as part of a charged particle optical apparatus. Such a charged particle optical apparatus includes a charged particle device and a source (if not part of the charged particle device) and an actuable stage for supporting a sample. The actuable stage can be actuated to move the sample from the column relative to the path of the charged particles. The charged particle device may be located on an area within a wafer fabrication facility. A charged particle system may include a charged particle device and an environmental control system, as well as a processor, such as a processing rack that can be located remotely from a portion of the system existing on the area of ​​the apparatus. Such an environmental control system includes portions of a thermal control system and a vacuum system.

[0207] References to a system of components or elements that can controllably manipulate a charged particle beam in a certain manner include configuring a controller or control system or control unit to control the component to manipulate the charged particle beam as described, and, where appropriate, using other controllers or devices (e.g., voltage suppliers and / or current suppliers) to control the component thereby manipulating the charged particle beam in this manner. For example, a voltage supplier may be electrically connected to one or more components to apply a potential to components such as those in an unrestricted list, under the control of a controller or control system or control unit, including control lens array 250, objective lens array 234, condenser lens 231, corrector, and scanning deflector array 260. Actuable components such as a stage may be controllable to actuate other components, such as the beam path, and thus move relative to those other components using one or more controllers, control systems, or control units used to control the actuation of the component.

[0208] The embodiments described herein may take the form of a series of aperture arrays or charged particle optics arranged in an array along a beam or multi-beam path. Such charged particle optics may be electrostatic. In one embodiment, all charged particle optics (e.g., from the beam-limiting aperture array to the last charged particle optic in the sub-beam path before the sample) may be electrostatic and / or may be in the form of an aperture array or plate array. In some configurations, one or more of the charged particle optics are fabricated as MEMS (i.e., using MEMS fabrication techniques).

[0209] The computer program may contain instructions to direct controller 50 to perform the following steps. Controller 50 controls the charged particle beam device to project a charged particle beam toward sample 208. In one embodiment, controller 50 controls at least one charged particle optical element (e.g., an array of multiple deflectors or scanning deflectors 260) to operate on the charged particle beam in the charged particle beam path. Alternatively, in one embodiment, controller 50 controls at least one charged particle optical element (e.g., a detector 240) to operate on the charged particle beam emitted from sample 208 in response to the charged particle beam.

[0210] Any element or assembly of elements may be replaceable within the electro-optical device 40 or field-replaceable. One or more charged particle optical components in the electro-optical device 40, particularly components that operate or generate sub-beams, such as aperture arrays and manipulator arrays, may comprise one or more MEMS.

[0211] Although the invention has been described in conjunction with various embodiments, other embodiments of the invention will become apparent to those skilled in the art from consideration of this specification and from the practice of the invention disclosed herein. This specification and examples are intended to be illustrative only, and the true scope and spirit of the invention are indicated by the following claims and provisions.

[0212] The following terms are provided. Term 1: A charged particle optical device configured to project multiple beams of charged particles, the device comprising: a charged particle device switchable between: (i) an operational configuration in which the device is configured to project multiple beams onto a sample along an operational beam path extending from the source of the multiple beams to the sample; and (ii) a monitoring configuration in which the device is configured to project multiple beams onto a detector along a monitoring beam path extending from the source to the detector; wherein the monitoring beam path deviates from the detection beam path midway through the operational beam path.

[0213] Clause 2: The charged particle optical device as described in Clause 1, wherein the device includes at least one movable component configured to move between an operating position corresponding to an operating configuration and a monitoring position corresponding to a monitoring configuration.

[0214] Clause 3: The charged particle optical device as described in Clause 2, wherein at least one movable component comprises a detector.

[0215] Clause 4: Charged particle optical devices as described in Clause 2 or 3, wherein the monitoring position is located between the source and the sample.

[0216] Clause 5: A charged particle optical device as described in any of Clauses 2 to 4, wherein at least one movable component includes a transducer configured to receive a multi-beam output from a source and to generate light in response to the received multi-beam.

[0217] Clause 6: The charged particle optical device of Clause 5, wherein at least one movable component includes a light guiding configuration configured to guide light generated by the converter toward the detector.

[0218] Clause 7: The charged particle device as described in Clause 5 or 6, wherein at least one movable component includes a mirror configured in a monitoring position to guide light generated by the converter to the detector.

[0219] Clause 8: A charged particle device as described in any of Clauses 1 to 4, wherein the device comprises: a transducer located in a multi-beam path for responding to the multi-beam to generate a beam; and a mirror configured in a monitoring configuration to ideally guide the beam to a detector in the monitoring configuration.

[0220] Clause 9: Charged particle device as in Clause 7 or 8, wherein the converter remains in the same position in the operating configuration and in the monitoring position.

[0221] Clause 10: A charged particle device as described in Clause 9, wherein in the converter, a plurality of apertures are defined so that the paths of multiple beams can ideally pass through in the operating configuration.

[0222] Clause 11: A charged particle optical device as described in any of Clauses 7 to 10, wherein a plurality of apertures are defined in a mirror, the plurality of apertures being configured to allow multiple beams to ideally pass through the mirror toward a sample in an operational configuration, wherein the mirror is configured to reflect light toward a detector.

[0223] Clause 12: A charged particle device as described in Clause 11, wherein, in the operating configuration, the paths of a plurality of beams in a multi-beam configuration pass through individual apertures defined in a mirror.

[0224] Clause 13: Charged particle device as in Clause 10 or 12, wherein, in the monitoring configuration, the paths of multiple beams in a multi-beam configuration are incident on the converter.

[0225] Clause 14: A charged particle optical device as described in any of the preceding clauses, wherein the device includes at least one deflector operable between a detection setting corresponding to an operating configuration and a measurement setting corresponding to a monitoring configuration, wherein ideally, the deflector is a giant deflector configured to operate on all beam paths of a multi-beam array, or the deflector is an array of deflector elements comprising a plurality of deflector elements to operate on individual beam paths of the multi-beam array.

[0226] Clause 15: A charged particle optical device as described in any of Clauses 2 to 14, wherein at least one movable component comprises one of a source and an objective array configured in an operational configuration to project multiple beams onto a sample.

[0227] Clause 16: A charged particle optical device as described in Clause 15, wherein in an operating configuration, the multiple beams are aligned with the lenses of the objective array, and in a monitoring configuration, the multiple beams are offset from the objective array, wherein ideally, the device includes an actuator configured to actuate the device between the operating and monitoring configurations.

[0228] Clause 17: The charged particle optical device as described in Clause 1, wherein the device includes a monitoring component in the monitoring beam path in the countercurrent direction of the detector.

[0229] Clause 18: The charged particle optical device as described in Clause 17, wherein the monitoring component includes an array of blocking elements configured to block multiple beams.

[0230] Clause 19: The charged particle optical device as described in Clause 18, wherein the blocking element has a similar pattern.

[0231] Clause 20. Charged particle optical apparatus as described in Clause 18 or 19, wherein the blocking element comprises a knife edge.

[0232] Clause 21: A charged particle optical device as described in any of Clauses 18 to 20, wherein the monitoring component includes an aperture array adjacent to each of the individual blocking elements for multiple beams to pass through.

[0233] Clause 22: The charged particle optical device as described in Clause 21, wherein the individual apertures of the aperture array correspond to the individual blocking elements of the blocking element array.

[0234] Clause 23: The charged particle optical apparatus of Clause 22, wherein individual blocking elements surround individual apertures.

[0235] Clause 24: A charged particle optical device as described in any of Clauses 21 to 23, wherein some blocking elements are annular.

[0236] Clause 25: The charged particle optical device as described in Clause 24, wherein individual blocking elements have an inner edge, ideally a knife edge, which is spaced apart from the rim of the individual aperture.

[0237] Clause 26: A charged particle optical device as described in any of Clauses 17 to 25, wherein the detector is spaced apart from the monitoring component along the path of the monitoring beam.

[0238] Clause 27: A charged particle optical device as described in any of Clauses 17 to 26, wherein the device includes at least one deflector operable between a detection setting corresponding to an operating configuration and a measurement setting corresponding to a monitoring configuration.

[0239] Clause 28: Charged particle optical apparatus as in Clause 27, wherein, in the measurement setup, at least one deflector is configured to scan a multi-beam over a portion of the monitoring component.

[0240] Clause 29: A charged particle optical device as described in Clause 28, wherein at least one deflector is configured to scan multiple beams such that the beams are scanned over a feature of an individual blocking element, ideally a knife edge.

[0241] Clause 30: A charged particle optical device as described in any of Clauses 17 to 29, wherein the detector is in the direction of the most downstream flow of the device, in the direction of the downstream flow of the charged particle optical element.

[0242] Clause 31: A charged particle optical device as described in any of Clauses 17 to 29, wherein the detector is associated with an objective lens assembly of the device, the objective lens assembly comprising an objective lens array configured to direct multiple beams onto a sample.

[0243] Clause 32: The charged particle optical device as described in Clause 31, wherein the detector is located at the end of the objective lens assembly in the countercurrent direction.

[0244] Clause 33: A charged particle optical device configured to project multiple beams of charged particles onto a sample, the device comprising: a source configured to output a source beam for generating multiple beams; an aperture array configured to form a plurality of beams from the source beam by projecting a portion of the source beam toward the sample through obstruction; and a detector configured to measure at least one parameter of at least a portion of the obstructed portion of the source beam.

[0245] Clause 34: A charged particle optical device as described in Clause 33, comprising a transducer configured to receive a source beam output from a source and to generate light in response to the received source beam.

[0246] Clause 35: A charged particle optical device as described in Clause 34, wherein the transducer is located on the surface of the aperture array in the opposite direction of the flow direction, wherein ideally, the received source beam comprises at least a proportion of the source beam blocked by the aperture array.

[0247] Clause 36: Charged particle optical device as described in Clause 34 or 35, comprising a mirror configured to reflect light generated by a converter toward a detector.

[0248] Clause 37: The charged particle optical device as described in Clause 36, wherein the mirror is positioned in the countercurrent direction of the converter, wherein ideally, the mirror is located between the converter and the source.

[0249] Clause 38: Charged particle optical apparatus as in Clause 36 or 37, wherein the mirror includes an aperture for receiving a source and / or a source beam.

[0250] Clause 39: A charged particle optical device configured to project multiple beams of charged particles onto a sample, the device comprising: a charged particle device including: an array of objectives configured to project multiple beams onto a portion of the sample; a plurality of transducers configured to receive signal particles emitted from the sample and to generate light in response to the received signal particles; and a light guiding configuration including a mirror defining a plurality of apertures to allow multiple beams to pass through the mirror toward the sample; and a light sensing assembly configured to guide light generated by the transducers to the light sensing assembly, wherein the light sensing assembly includes: an evaluation sensor and a detector, each configured to detect light generated by the transducers; and a beam splitter configured to split the light generated by the transducers into beams for use by the evaluation sensor and the detector.

[0251] Clause 40: A charged particle optical device as described in Clause 39, comprising a controller configured to match the detection signal of an evaluation sensor to a portion of a sample projected by a multi-beam array based on the detection signal of the sensor, wherein ideally, the transducer is a scintillator.

[0252] Clause 41: A charged particle optical device as described in any of the preceding clauses, wherein the detector is configured to detect light.

[0253] Clause 42: A charged particle optical device as described in any of Clauses 1 to 35 and 39 to 41, wherein the detector is configured to detect charged particles.

[0254] Clause 43: The charged particle optical device of Clause 42, wherein the detector comprises one of a Faraday cup array, a charge-coupled device, and a direct light detector device, the direct light detector device comprising: a transducer configured to generate light in response to charged particles; and an adjacent optical detector preferably in contact with the transducer, the adjacent optical detector being configured to directly convert the light signal generated by the transducer into an electrical signal.

[0255] Clause 44: A charged particle optical device as described in any of the preceding clauses, wherein the detector is configured to measure at least one of the following: the uniformity of the multibeams, the alignment of the multibeams, and the aberrations of the multibeams.

[0256] Clause 45: A charged particle optical device as described in Clause 44, wherein the aberration is at least one of field curvature, distortion and astigmatism.

[0257] Clause 46: A charged particle optical device as described in any of the preceding clauses, wherein the source is configured to emit electrons.

[0258] Clause 47: A method for projecting multiple beams of charged particles, the method comprising: using a charged particle device in an operational configuration to project multiple beams onto a sample along an operational beam path from the source of the multiple beams to the sample; and using a device in a monitoring configuration to project multiple beams onto a detector along a monitoring beam path extending from the source to the detector; wherein the monitoring beam path deviates from the operational beam path midway through the operational beam path.

[0259] Clause 48: A method for projecting multiple beams of charged particles, the method comprising: in an operational configuration, projecting multiple beams onto a sample along an operational beam path from the source of the multiple beams to the sample; and in a monitoring configuration, projecting multiple beams onto a detector along a monitoring beam path from the source to the detector and causing the monitoring beam path to deviate from the operational beam path midway through the operational beam path.

[0260] Clause 49: A method for projecting a multiple beam of charged particles onto a sample, the method comprising: using a source to output a source beam of multiple beams; using an aperture array to form a plurality of beams of multiple beams from the source beam by projecting a portion of the source beam toward the sample through obstruction; and using a detector to measure at least one parameter of at least a portion of the obstructed portion of the source beam.

[0261] Clause 50: A method for projecting a multi-beam of charged particles onto a sample, the method comprising: a source beam from which a multi-beam is generated; forming a plurality of beams in the multi-beam by projecting a portion of the source beam toward the sample by blocking a proportion of the source beam at an aperture array; and ideally using a detector to measure at least a portion of the blocked proportion of the source beam.

[0262] Clause 51: A method for projecting multiple beams of charged particles onto a sample, the method comprising: using an objective array configured to project multiple beams onto a portion of the sample; using a plurality of transducers (ideally scintillators) to receive signal particles emitted from the sample and to generate light in response to the received signal particles; using a light guiding configuration to guide the light generated by the transducers to a photosensitive assembly, wherein the light guiding configuration includes a mirror defining a plurality of apertures to allow multiple beams to pass through the mirror toward the sample; and using a beam splitter to split the light generated by the transducers into a plurality of beams for evaluation sensors and detectors; and using the evaluation sensors and detectors to detect the light generated by the transducers.

[0263] Clause 52: A method for projecting multiple beams of charged particles onto a sample, the method comprising: ideally using an array of objectives to project multiple beams onto a portion of the sample; ideally using a plurality of transducers (ideally scintillators) to receive signal particles emitted from the sample and to generate light in response to the received signal particles; using a light guiding configuration to guide the generated light to a photosensitive assembly, wherein the light guiding configuration includes mirrors defining a plurality of apertures to allow multiple beams to pass through the mirrors toward the sample; and ideally using a beam splitter to split the generated light into a plurality of beams, preferably for evaluation sensors and detectors; and ideally using the evaluation sensors and detectors to detect the generated light.

[0264] 10:Main chamber 20: Loading locking chamber 30: Equipment front-end module 30a: Loading Port 30b: Loading Port 40: Electro-optical devices 41: Electro-optical devices 50: Controller 56: Opening 60: Converter 61: Camera 62: Mirror 63: Optical Components 64: Surveillance Detector 65: Aperture 66: Switch beam path 67: Switch beam path 68: Switch beam path 69: Source Module 70: Objective lens module 71: Coating 72: Mirror 73: Aperture 75: Optical detector 76: Optical Components 77: Beam Splitter 78: Switching the deflector array 100: Charged Particle Beam Detection Device 190: Monitoring Components 191: Thicker area 192: Thinner area 193: Aperture 194: Blocking element 195: Wheel Edge 196: Uncovered Area 197: Inner Edge 201: Electronic Source 202: Source beam / Primary electron beam 207: Sample Holder 208: Sample 209: Platform 211:sub-beam 212:sub-beam 213:sub-beam 221: Detecting the light spot 222: Detecting the light spot 223: Detecting the light spot 230: Projection device 231: Condensing Lens 233: Central Focus 234: Objective lens 235: Deflector 240: Electronic detection devices 250: Control lens array 251: Control Lens 260: Scan deflector array 301: Electrode 302: Electrode 401: Objective lens 402: Detector Module 403: Objective lens array 404:Substrate 405: Capture Electrode 406: Beam Aperture 407: Logic Layer 408: Wiring Layer 409: Silicon perforation 410: Converter 411: Light 412: Light sensor 414: Mirror 416: Aperture 417: Aperture 418: Optical components 420: Outer shell 422: Data Line 641: Detection element 642: Detector board 643: Aperture

Claims

1. A charged particle optical device configured to project a charged particle multi-beam, the device comprising: a charged particle device switchable between: (i) an operational configuration, wherein the device is configured to project the multi-beam onto the sample along an operational beam path extending from a source of the multi-beam to a sample; and (ii) a monitoring configuration, wherein the device is configured to project the multi-beam onto the detector along a monitoring beam path extending from the source to a detector; wherein the monitoring beam path diverts from the operational beam path midway through the operational beam path.

2. The charged particle optical device of claim 1, wherein the device includes at least one movable component configured to move between an operating position corresponding to the operating configuration and a monitoring position corresponding to the monitoring configuration.

3. The charged particle optical device as claimed in claim 2, wherein the at least one movable component includes the detector.

4. The charged particle optical device as claimed in claim 2 or 3, wherein the monitoring position is located between the source and the sample.

5. The charged particle optical device of claim 2 or 3, wherein the at least one movable component includes a transducer configured to receive the multi-beam output from the source and to generate light in response to the received multi-beam.

6. The charged particle optical device of claim 5, wherein the at least one movable component includes a light guiding configuration configured to guide the light generated by the converter toward the detector.

7. The charged particle optical device of claim 5, wherein the at least one movable component includes a mirror configured in the monitoring position to guide the light generated by the converter to the detector.

8. The charged particle optical device of claim 7, wherein the converter remains in the same position in the operating configuration and in the monitoring position.

9. The charged particle optical device of claim 8, wherein in the converter, a plurality of apertures are defined so that the paths of the multiple beams are ideally passed through in an operating configuration.

10. The charged particle optical device of claim 7, wherein a plurality of apertures are defined in the mirror, the plurality of apertures being configured to allow the multiple beams to ideally pass through the mirror toward the sample in the operating configuration, wherein the mirror is configured to reflect light toward the detector.

11. The charged particle optical device of claim 10, wherein, in the operating configuration, the paths of the plurality of beams in the multiple beams pass through individual apertures defined in the mirror.

12. The charged particle optical device of claim 9, wherein, in the monitoring configuration, the paths of the plurality of beams in the multiple beams are incident on the converter.

13. A charged particle optical device as claimed in any one of claims 1 to 3, wherein the device includes at least one deflector operable between a detection setting corresponding to the operating configuration and a measurement setting corresponding to the monitoring configuration.

14. A charged particle optical device as claimed in any of claims 2 or 3, wherein the at least one movable component comprises one of the source and an objective array configured in the operating configuration to project the multi-beam onto the sample.

15. The charged particle optical device of claim 14, wherein in the operating configuration, the multiple beam is aligned with the lenses of the objective array, and in the monitoring configuration, the multiple beam is deflected from the objective array, wherein ideally, the device includes an actuator configured to actuate the device between the operating configuration and the monitoring configuration.

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