Sensor substrates, devices and methods

Abstract

The invention provides a sensor substrate for a charged particle optical apparatus and / or a charged particle evaluation apparatus, the sensor substrate comprising: at least one distance sensor configured to generate a measurement signal representative of a distance between the distance sensor and a facing surface of a target; and at least one charged particle optical component.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to EP application 22167493.0 filed on April 8, 2022, and the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments provided herein generally relate to sensor substrates, devices, and methods. Background Art

[0004] When manufacturing semiconductor integrated circuit (IC) chips, undesirable pattern defects will inevitably appear on the substrate (i.e., wafer) or mask during the manufacturing process due to optical effects and accidental particles, thereby reducing the yield. Therefore, monitoring the degree of undesirable pattern defects is an important process in IC chip manufacturing. More generally, inspecting and / or measuring the surface of a substrate or other object / material during and / or after its manufacture is an important process.

[0005] Pattern inspection tools with charged particle beams have been used to inspect objects, such as detecting pattern defects. These tools typically use electron microscopy techniques, such as scanning electron microscopes (SEMs). In SEMs, a primary electron beam with relatively high energy electrons is targeted at a final deceleration step so as to land on a sample with a relatively low landing energy. The electron beam is focused as a probe point on the sample. The interaction between the material structure at the probe point and the landing electrons from the electron beam causes signal particles (e.g., electrons) to be emitted from the surface, such as secondary electrons, backscattered electrons, or Auger electrons. The generated signal particles can be emitted from the material structure of the sample. By scanning the sample surface using the primary electron beam as a probe point, signal particles can be emitted across the surface of the sample. By collecting these emitted signal particles from the sample surface, the pattern inspection tool can obtain data representing the material structure characteristics of the sample surface. The data can be referred to as an image and can be drawn into an image.

[0006] Generally, it is important to know the specific position of certain components (such as detectors) relative to other components or members and / or samples (or sample positions). However, it is difficult to know the exact position of a component due to mechanical tolerances between the component and the sensor used to detect the position of the component. Additionally, the amount of space used to introduce sensors to accurately detect the position of the component is limited. Summary of the invention

[0007] An object of the present disclosure is to provide a method of measuring the distance to a target, such as a sample surface or a sample location.

[0008] According to one aspect of the present invention, a sensor substrate for a charged particle optical device and / or a charged particle evaluation apparatus is provided, the sensor substrate comprising: at least one distance sensor configured to generate a measurement signal representing the distance between the distance sensor and a facing surface of a target; and at least one charged particle optical component.

[0009] According to one aspect of the present invention, a sensor substrate for a multi-beam charged particle optical device and / or a charged particle evaluation apparatus is provided, the sensor substrate comprising a plurality of distance sensors configured to generate a measurement signal representing the distance between the distance sensors and a facing surface of a target.

[0010] According to one aspect of the present invention, there is provided a charged particle device for projecting a multi-beam charged particle towards a sample location, the charged particle device comprising a sensor substrate as described herein.

[0011] According to one aspect of the present invention, a charged particle evaluation device for evaluating a sample is provided, the charged particle evaluation device desirably being configured to project a charged particle beam toward the sample, the charged particle evaluation device comprising the sensor substrate described herein, desirably comprising a source configured to emit a charged particle beam, and desirably comprising the charged particle device described herein, wherein the charged particle device comprises the sensor substrate.

[0012] According to one aspect of the present invention, there is provided a charged particle evaluation device for evaluating a sample, the charged particle evaluation device comprising the sensor substrate described herein.

[0013] According to one aspect of the present invention, there is provided a method for generating a measurement signal representing the distance between a distance sensor and a facing surface of a target using a sensor substrate, the sensor substrate comprising at least one distance sensor and at least one charged particle optical element, the method comprising: a) positioning the sensor substrate so that the distance sensor faces the facing surface of the target; and b) generating a measurement signal representing the distance between the distance sensor and the facing surface of the target using the distance sensor.

[0014] According to one aspect of the present invention, there is provided a method for generating a measurement signal representing the distance between the distance sensor and a facing surface of a target using a sensor substrate including a plurality of distance sensors, the method comprising: a) positioning the sensor substrate so that the distance sensor faces the facing surface of the target; and b) generating a measurement signal representing the distance between the distance sensor and the facing surface of the target using the distance sensor.

[0015] According to one aspect of the present invention, a method for projecting a charged particle beam onto a sample is provided so as to detect signal particles emitted from the sample using a sensor substrate, the sensor substrate comprising at least one distance sensor and at least one signal detector, the method comprising: a) positioning the sensor substrate so that the distance sensor faces a facing surface of the sample; b) using the distance sensor to generate a measurement signal representing the distance between the distance sensor and the facing surface of the sample; c) controlling the position of the sensor substrate and / or the sample and / or the sample holder based on the measurement signal; d) projecting the charged particle beam onto the surface of the sample along a primary beam path; and e) detecting the signal particles emitted from the sample at at least one signal detector. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 1 is a schematic diagram illustrating an exemplary charged particle beam evaluation (eg, inspection) apparatus.

[0018] Figure 2 is shown as Figure 1 Schematic diagram of an exemplary multi-beam apparatus that is a portion of an exemplary charged particle beam evaluation apparatus.

[0019] Figure 3 is a schematic diagram of an exemplary multi-beam apparatus according to one embodiment.

[0020] Figure 4 yes Figure 3 Bottom view of the detector assembly section

[0021] Figure 5A and Figure 5B A bottom view of a detector variant is shown.

[0022] Fig. 6A and Figure 6B is a schematic diagram of a detector array and an associated cell array according to one embodiment, a schematic diagram of a cell of a cell array, and a schematic diagram of a cell of a cell array according to one embodiment.

[0023] Figure 7 is a schematic diagram showing a cross-sectional wiring diagram of a circuit conductor and shielding arrangement according to one embodiment.

[0024] Figure 8 is a schematic diagram of a sensor substrate according to one embodiment.

[0025] Fig. 9 yes Figure 8 Schematic cross-sectional view of a sensor substrate in FIG.

[0026] Fig.10 is a schematic cross-section of a sensor substrate according to one embodiment.

[0027] Fig.11 is a schematic cross-section of a sensor substrate according to one embodiment.

[0028] The drawings are schematic. The schematic diagrams and views show the components described below. However, the components depicted in the drawings are not drawn to scale. For the sake of clarity, the relative sizes of the components in the drawings are exaggerated. In the following description of the drawings, the same or similar reference numbers represent the same or similar components or entities, and only the differences with respect to the various embodiments are described. DETAILED DESCRIPTION

[0029] Reference will now be made in detail to exemplary embodiments, examples of which are shown in the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise specified, the same numbers in different figures represent the same or similar elements. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the present invention. Instead, they are merely examples of substrates, devices (or arrays of devices), components, arrays, devices, systems, and methods consistent with the various aspects related to the present invention described in the appended claims.

[0030] The increase in computing power of electronic devices has led to a reduction in the physical size of electronic devices, which can be achieved by significantly increasing the packing density of circuit components such as transistors, capacitors, diodes, etc. on IC chips. This is made possible by the increased resolution that allows the manufacture of smaller structures. For example, a thumbnail-sized IC chip for a smartphone, which will be launched in 2019 or earlier, may include more than 2 billion transistors, each less than one thousandth the size of a human hair. It is therefore not surprising that semiconductor IC manufacturing is a complex and time-consuming process involving hundreds of individual steps. Even an error in one step has the potential to greatly affect the functionality of the final product. Just one defect can cause an electronic device to fail. The goal of the manufacturing process is to increase the overall yield of the process. For example, to achieve a 75% yield for a 50-step process (where the step indicates the number of layers formed on the wafer), the yield of each individual step must be greater than 99.4%. If the yield of each individual step is 95%, the yield of the entire process would be as low as 7%.

[0031] While high process yield is desirable in IC chip fabrication plants, it is also essential to maintain high substrate (i.e., wafer) throughput (defined as the number of substrates processed per hour). High process yield and high substrate throughput may be affected by the presence of defects. This is especially true if operator intervention is required to detect the defect. Therefore, high throughput detection and identification of micron and nanometer-scale defects by inspection systems, such as scanning electron microscopes (SEMs), is critical to maintaining high yields and low costs.

[0032] The SEM includes a scanning device and a detector device. The scanning device includes an irradiation device, which includes an electron source for generating primary electrons, and a projection device for scanning a sample (e.g., a substrate) with one or more focused primary electron beams. The irradiation device or irradiation system and the projection device or projection system can at least be collectively referred to as an electron optical system or device. The primary electrons interact with the sample and generate signal particles, such as secondary electrons and / or backscattered electrons. The detection device captures the signal particles from the sample as the sample is scanned so that the SEM can create an image of the scanned area of ​​the sample. For high-throughput inspection, some inspection devices use multiple focused primary beams of primary electrons, i.e., multi-beams. The constituent beams of the multi-beams can be referred to as sub-beams or sub-beam or primary beam arrays. Multiple beams can scan different parts of the sample simultaneously. Therefore, a multi-beam inspection (or evaluation) device can inspect the sample at a much higher speed than a single-beam inspection (or evaluation) device. A known implementation of a multi-beam inspection system is described below.

[0033] Reference now Figure 1 , which is a schematic diagram illustrating an exemplary charged particle beam evaluation system 100 . Figure 1 The charged particle beam evaluation system 100 includes a main chamber 10, a load lock chamber 20, a charged particle beam device 40 (which may also be referred to as an electron beam device), an equipment front end module (EFEM) 30, and a controller 50. The charged particle beam device 40 is located in the main chamber 10.

[0034] The EFEM 30 includes a first loading port 30a and a second loading port 30b. The EFEM 30 may include additional loading ports. The first loading port 30a and the second loading port 30b may, for example, receive a substrate front opening pod (FOUP) containing a substrate (e.g., a semiconductor substrate or a substrate made of other (multiple) materials) or a sample to be inspected (substrate, wafer and sample are collectively referred to as "sample" hereinafter). One or more robotic arms (not shown) in the EFEM 30 transport the sample to the load lock chamber 20.

[0035] The load lock chamber 20 is used to remove the gas around the sample. This creates a vacuum, that is, the local gas pressure is lower than the pressure of the surrounding environment. After reaching a first pressure lower than atmospheric pressure, one or more robotic arms (not shown) transport the sample from the load lock chamber 20 to the main chamber 10. The main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas particles in the main chamber 10 so that the pressure around the sample reaches a second lower pressure. After reaching the second pressure, the sample is transported to the charged particle beam device 40 to be examined by the device. Depending on the configuration used, the second pressure may be higher than 10 -7 Up to 10 -5 The range between mbar is low. The charged particle beam tool 40 may include multi-beam charged particle optics.

[0036] The controller 50 is electrically connected to the charged particle beam tool 40. The controller 50 may be a processor (such as a computer) configured to control the charged particle beam evaluation (e.g., inspection) device 100. The controller 50 may include processing circuitry configured to perform various signal and image processing functions. Figure 1 The controller 50 is shown as being located outside the structure including the main chamber 10, the load lock chamber 20 and the EFEM 30, but it is understood that the controller 50 can be part of the structure. The controller 50 can be located in one of the components (e.g., elements or components) of the charged particle beam evaluation device 100, or can be distributed on at least two components. Although the present disclosure provides an example of a main chamber 10 that accommodates a charged particle beam evaluation device 100, it should be noted that aspects of the present disclosure in its broadest sense are not limited to a chamber that accommodates a charged particle beam evaluation device 100. On the contrary, it is understood that the aforementioned principles can also be applied to the arrangement of other tools and other devices operating at a second pressure.

[0037] Reference now Figure 2 , which is a schematic diagram showing an exemplary charged particle beam tool 40, the charged particle beam tool including a multi-beam inspection tool, the multi-beam inspection tool is Figure 1 A portion of an exemplary charged particle beam evaluation apparatus 100 of the present invention. A multi-beam charged particle beam tool 40 (also referred to herein as the apparatus 40) includes a charged particle source 201, a projection device 230, an actuation stage 209, and a sample holder 207. The charged particle source 201 and the projection device 230 may be collectively referred to as an irradiation device. The features of the charged particle beam apparatus 40 that do not include the source 201 and the sample 208, the sample holder 207, and the actuation stage 209 may be collectively referred to as a charged particle device 41. The sample holder 207 is supported by the actuation stage 209 so as to hold the sample 208 (e.g., a substrate or a mask) for inspection. The multi-beam charged particle beam tool 40 also includes a detector array 240 (e.g., an electronic detection device).

[0038] The controller 50 may be connected to Figure 1 The controller 50 may be connected to the various parts of the charged particle beam evaluation device 100. Figure 2 The controller 50 may control various parts of the charged particle beam tool 40, such as the charged particle source 201, the detector array 240, the projection device 230 and the actuation stage 209. The controller 50 may perform various data, image and / or signal processing functions. The controller 50 may also generate various control signals to control the operation of the charged particle beam evaluation device 100, which includes a charged particle multi-beam device. The controller 50 may control the actuation stage 209 to move the sample 208 during the inspection of the sample 208. The controller 50 may cause the actuation stage 209 to move the sample 208 in a certain direction at least during the sample inspection (e.g., continuously, such as at a constant speed). The controller 50 may control the movement of the actuation stage 209 so that it changes the movement speed of the sample 208 according to various parameters. For example, the controller 50 may control the stage speed (including its direction) according to the characteristics of the inspection step of the scanning process.

[0039] The charged particle source 201 may include a cathode (not shown) and an extractor or anode (not shown). During operation, the charged particle source 201 is configured to emit charged particles (e.g., electrons) from the cathode as primary charged particles. The primary charged particles are extracted or accelerated by the extractor and / or anode to form a primary charged particle beam 202. The charged particle source 201 may include a plurality of sources, such as described in EP20184161.6, which is incorporated herein by reference at least in relation to a plurality of sources and how they are associated with a plurality of device columns (or at least a plurality of charged particle devices) and their associated charged particle optical devices.

[0040] The projection device 230 is configured to convert the primary charged particle beam 202 into a plurality of sub-beams 211, 212, 213 and direct each sub-beam onto the sample 208. Although only three sub-beams are shown for simplicity, there may be tens, hundreds, or thousands of sub-beams. A sub-beam may be referred to as a sub-beam. In addition, although the present specification and the accompanying drawings relate to a multi-beam system, a single-beam system may be used in which the primary charged particle beam 202 is not converted into a plurality of sub-beams. The sub-beams are generally interchangeable with a single primary charged particle beam 202. For example, a single-beam system as described in US2021 / 0319977 may be used.

[0041] The projection device 230 may be configured to focus the sub-beams 211, 212, and 213 onto the sample 208 for inspection, and may form three detection points 221, 222, and 223 on the surface of the sample 208. The projection device 230 may be configured to deflect the primary sub-beams 211, 212, and 213 to scan the detection points 221, 222, and 223 across respective scanning areas in a portion of the surface of the sample 208. In response to the primary sub-beams 211, 212, and 213 being incident on the detection points 221, 222, and 223 on the sample 208, signal charged particles (e.g., electrons) are generated (i.e., emitted) from the sample 208, which include secondary signal particles and backscattered signal particles. The signal particles emitted from the sample, e.g., secondary electrons and backscattered electrons, may also be referred to as charged particles, e.g., secondary charged particles and backscattered charged particles. The signal beam is formed by the signal particles emitted from the sample. It is generally understood that any signal beam emitted from the sample 208 will travel in a direction having at least one component substantially opposite to the charged particle beam (i.e., the primary beam), or will have at least one directional component opposite to the direction of the primary beam. The signal particles emitted by the sample 208 may also pass through the electrodes of the objective lens and may also be affected by the field.

[0042] The detector array 240 is configured to detect (i.e., capture) signal particles emitted from the sample 208. The detector array 240 is configured to generate corresponding signals, which are sent to the signal processing system 280, for example, to construct an image of the corresponding scan area of ​​the sample 208. The detector array 240 can be incorporated into the projection device 230. The detector array can also be called a sensor array, and the terms "detector" and "sensor" and "sensor unit" are used interchangeably throughout the application.

[0043] The signal processing system 280 may include circuitry (not shown) configured to process signals from the detector array 240 to form an image. The signal processing system 280 may also be referred to as an image processing system or a data processing system. The signal processing system may be incorporated into a component of the multi-beam charged particle beam tool 40, such as the detector array 240 (e.g., Figure 2 However, the signal processing system 280 may be incorporated into any component of the inspection apparatus 100 or the multi-beam charged particle beam tool 40, such as as part of the projection device 230 or the controller 50. The signal processing system 280 may be located in a Figure 1The structure of the main chamber shown in the figure is outside. The signal processing system 280 may include an image acquisition device (not shown) and a storage device (not shown). For example, the signal processing system may include a processor, a computer, a server, a mainframe mainframe, a terminal, a personal computer, any type of mobile computing device, etc., or a combination thereof. The image acquisition device may include at least part of the processing function of the controller. Therefore, the image acquisition device may include at least one or more processors. The image acquisition device may be communicatively coupled to the detector array 240 to allow signal communication, such as an electrical conductor, a fiber optic cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, radio, etc., or a combination thereof. The image acquisition device may receive a signal from the detector array 240, may process the data included in the signal, and may construct an image therefrom. Therefore, the image acquisition device may acquire an image of the sample 208. The image acquisition device may also perform various post-processing functions, such as generating a contour, superimposing an indicator on the acquired image, etc. The image acquisition device may be configured to perform adjustments such as brightness and contrast of the acquired image. The memory can be a storage medium such as a hard disk, a flash drive, a cloud storage, a random access memory (RAM), other types of computer-readable memory, etc. The memory can be coupled to the image acquirer and can be used to save the scanned raw image data as raw images and post-processed images.

[0044] The signal processing system 280 may include a measurement circuit system (e.g., an analog-to-digital converter) to obtain a distribution of the detected secondary signal particles. The electron distribution data collected during the detection time window can be used in conjunction with the corresponding scan path data of each primary sub-beam 211, 212, and 213 incident on the sample surface to reconstruct an image of the inspected sample structure. The reconstructed image can be used to reveal various features of the internal or external structure of the sample 208. Therefore, the reconstructed image can be used to reveal any defects that may be present in the sample.

[0045] Known multi-beam systems, such as the above-mentioned charged particle beam tool 40 and the charged particle beam evaluation device 100, have been disclosed in US2020118784, US20200203116, US2019 / 0259570 and US2019 / 0259564, which are incorporated herein by reference.

[0046] The components (eg, charged particle components) of the charged particle beam apparatus 40 or the charged particle device 41 (eg, the evaluation apparatus 100) that can be used in the present invention are hereinafter referred to as Figure 3 Describe, Figure 3 2 is a schematic diagram of the charged particle beam device 40 . Figure 3 The charged particle beam device 40 may correspond to a multi-beam charged particle beam tool (also referred to herein as device 40 ).

[0047] The charged particle source 201 directs the charged particles (e.g., electrons) to a converging lens array 231 (also referred to as a converging lens array), which forms part of the projection system 230. The charged particle source 201 is expected to be a high brightness thermal field emitter with a good compromise between brightness and total emission current. There may be tens, hundreds, or thousands of converging lenses 231. The converging lens 231 may include a multi-electrode lens and have a construction based on EP1602121A1, which is incorporated herein by specifically citing the disclosure of a lens array for dividing an electron beam into a plurality of sub-beams, which provide a lens for each sub-beam. The converging lens array 231 may take the form of at least two plates, acting as electrodes, with the apertures in each plate aligned with each other and corresponding to the position of the sub-beams. At least two plates are maintained at different potentials during the operation process to achieve the desired lens effect.

[0048] In one arrangement, the array of converging lenses 231 is formed by an array of three plates, in which the charged particles have the same energy when entering and leaving each lens, which arrangement can be called an Einzel lens. Therefore, dispersion only occurs within the Einzel lens itself (between the entrance and exit electrodes of the lens), thereby limiting off-axis chromatic aberration. This document is incorporated herein by reference at least with respect to the features of the objective lens array disclosed therein. There may be some variations for optimizing the aberration correction, as described in EP application 20207178.3 filed on November 12, 2020, for example in Figure 12, which document is incorporated herein by reference at least with respect to the correction achieved by changing the aperture diameter.

[0049] A voltage source (which may be provided by a separate power supply or all powered by power supply 290) may be used to apply a potential to at least one electrode of objective lens array 241, at least one electrode of control lens 250, and / or the sample to control the projection of the primary beam through objective lens array 241, as described in EP application 20207178.3 filed on November 12, 2020 (e.g., FIG. 14) and EP 21174518.7 filed on May 18, 2021. Variations in the potential may be used for different landing energies to control the beam opening angle and / or the focusing of the primary beam on the sample. The potential may be controlled to accelerate or decelerate the primary beam through objective lens array 241 toward the sample.

[0050] Array 240 (also referred to as a detector array) includes a plurality of detectors. Each detector is associated with a corresponding sub-beam (also referred to as a light beam or a primary beam). In other words, the detector array (i.e., detector array 240) corresponds to a sub-beam. Each detector can be assigned to a sub-beam. The detector array can correspond to an objective lens array. In other words, the detector array can be associated with a corresponding objective lens array. The detector array 240 is described below. However, any reference to the detector array 240 can be replaced with a single detector (i.e., at least one detector) or multiple detectors as desired. The detector can also be referred to as a detector element 405 (e.g., a sensor element, such as a capture electrode). The detector can be any suitable type of detector. The detector can be a type of charged particle optical component.

[0051] The detector array 240 can be positioned at any position between the upper beam position and the lower beam position along the beam path at a position along the primary beam. The upper beam position is located above the objective array, and optionally above any associated lens array, such as a control lens array (i.e., the upstream of the objective array assembly). The lower beam position is downstream of the objective array. In one arrangement, the detector array can be an array upstream of the objective array assembly. The detector array can be associated with any electrode of the objective array assembly. Unless otherwise expressly stated, the detector associated with the electrode of the objective array hereinafter can correspond to an electrode of the objective array assembly, except for the most downstream surface of the most downstream electrode of the objective array.

[0052] In one arrangement, the detector array 240 can be positioned between the control lens array 250 and the sample 208. The detector array 240 can be positioned between the objective lens 234 and the sample 208, such as Figure 3 Although this may be desirable, the detector array 240 may be disposed in additional or alternative locations. Multiple detector arrays may be disposed in various locations.

[0053] The detector array 240 may be positioned close to and / or adjacent to the sample. Detectors close to and / or adjacent to the sample enable the risk of crosstalk when detecting signal particles generated by a beamlet corresponding to another detector in the detector array to be reduced, if not avoided.

[0054] Figure 4 4 is a bottom view (i.e., a plan view) of the detector array 240, which includes a substrate 404 on which a plurality of detector electrodes 405 are disposed, each of which surrounds a beam aperture 406. The beam aperture 406 may be formed by etching through the substrate 404. Figure 4In the illustrated arrangement, the beam apertures 406 are shown in a hexagonal close-packed array. The beam apertures 406 may also be arranged in a different manner, such as in a rectangular array. The detector electrodes 405 are isolated from each other by gaps between the detector electrodes 405. In addition, the substrate 404 isolates the detector elements 405 from each other and may be referred to as an isolation element.

[0055] The detector array 240 can be located within a certain distance of the sample 208, for example, close to the sample. At least one detector can be positioned in the device 41 so as to face the sample. Therefore, at least one detector can be configured to face a sample support configured to support the sample 208, for example, the sample holder 207. That is, the detector can provide a base for the device 41. As part of the base, the detector can face the surface of the sample. The base can have a cross-sectional area and can be referred to as a surface facing the sample. (In certain types of evaluation devices that may include charged particle devices, the surface facing the sample can be referred to as a microscope base or head).

[0056] For example, at least one detector array may be arranged on the output side of the objective lens array 241. The output side of the objective lens array 241 is the side where the sub-beams are output from the objective lens array 241, i.e. Figure 3 The detector array 240 may be disposed at the bottom or downstream of the objective array in the configuration shown. In other words, the detector array 240 may be disposed downstream of the objective array 241. The detector array 241 may be an integrated feature of the objective array 241. The detector and the objective may be part of the same structure. The detector may be connected to the lens or directly to an electrode of the objective via an isolation element. Thus, at least one detector may be part of an objective assembly that includes at least the objective array and the detector array. If the detector array is an integral feature of the objective array 241, the detector array 240 may be disposed at the base of the objective array 241. In one arrangement, the detector array 240 may be integrated with the electrode positioned most downstream of the objective array 241.

[0057] Expectedly, as Figure 3 The distance "L" between the detector array 240 and the sample 208 shown is about 20 to 100 μm, that is, the detector array 240 is located within a range of about 20 to 100 microns from the sample 208. Typically, the distance L is small to ensure detector efficiency and / or reduce crosstalk, for example, between 5 and 200 microns. The distance L is determined as the distance between the surface of the sample 208 facing the detector array 240 and the surface of the detector array 241 facing the sample 208.

[0058] In one embodiment, the objective lens array 241 is a replaceable module that can be used alone or in combination with other components (such as a control lens array and / or a detector array). The replaceable module can be field replaceable, that is, a field engineer can replace the module with a new module. In one embodiment, multiple replaceable modules are included in the tool and can be exchanged between operable and inoperable positions without opening the tool.

[0059] In some embodiments, one or more aberration correctors are provided to reduce one or more aberrations in the sub-beam. One or more aberration correctors may be provided in any embodiment, for example as part of the charged particle optical device 41, and / or as part of an optical lens array assembly, and / or as part of an evaluation tool. In one embodiment, each aberration corrector in at least a subset of the aberration correctors is positioned in an intermediate focus or directly adjacent to one of the intermediate focuses (e.g., in an intermediate image plane or adjacent to an intermediate image plane). The sub-beam has a minimum cross-sectional area in or near a focal plane (such as an intermediate plane). This provides more room for the aberration corrector than is available elsewhere (i.e., upstream or downstream of the intermediate plane) (or more space than is available in an alternative arrangement without an intermediate image plane).

[0060] In one embodiment, an aberration corrector positioned in or directly adjacent to the intermediate focus (or intermediate image plane) includes a deflector to correct for the situation where the source 201 appears to be in different positions for different beamlets. The corrector can be used to correct for macroscopic aberrations introduced by the source that would prevent good alignment between each beamlet and the corresponding objective.

[0061] The aberration corrector can correct aberrations that prevent correct device column alignment (or alignment of charged particle components along the beam path from the source to the sample position of the charged particle device). Such aberrations may also cause poor alignment between the sub-beams and the corrector. To this end, it may be desirable to additionally or alternatively position the aberration corrector at or near the converging lens 231 (for example, each such aberration corrector is integrated with or directly adjacent to one or more converging lenses 231). This is desirable because at or near the converging lens 231, the aberration has not yet caused a deviation of the corresponding sub-beam because the converging lens is vertically close to or coincides with the beam aperture. The converging lens and the corrector can be part of the same structure. For example, they can be connected to each other, for example by an electrically isolating element. The aberration corrector can be a CMOS-based individually programmable deflector as disclosed in EP2702595A1 or a multipole deflector array as disclosed in EP2715768A2, the descriptions of the sub-beam manipulators in these two documents are hereby incorporated herein by reference.

[0062] In some embodiments, each aberration corrector in at least a subset of the aberration correctors is integrated with or directly adjacent to one or more objective lenses 234. In one embodiment, the aberration correctors reduce one or more of: field curvature; focus error; and astigmatism. Additionally or alternatively, one or more scanning deflectors (not shown) can be integrated with or directly adjacent to one or more objective lenses 234 for scanning the sub-beams 211, 212, 213 over the sample 208. In one embodiment, the scanning deflectors described in US2010 / 0276606, which is hereby incorporated by reference in its entirety, can be used.

[0063] In one embodiment, a single detector element 405 surrounds each beam aperture 406. In another embodiment, multiple detector elements 405 surround each beam aperture 406. Thus, the detector includes multiple parts, more specifically, multiple detection parts. Multiple detector parts can have a circular circumference and / or diameter together. Multiple detector parts can have an area extending between the aperture and the circumference of multiple detector parts together. Different parts can be called different zones. Therefore, the detector can be described as having multiple zones or detection zones. Such a detector can be called a partitioned detector. Signal particles captured by the detector elements 405 surrounding a beam aperture 406 can be combined into a single signal or used to generate independent signals. The surface of the detector elements (optionally their detector parts) can substantially fill the surface of the substrate supporting the detector elements. Detectors comprising multiple parts can be arranged in any detector array described herein.

[0064] The partitioned detector may be associated with one of the sub-beams 211, 212, 213. Thus, multiple sections of a detector may be configured to detect signal particles emitted from the sample 208 associated with one of the sub-beams 211, 212, 213. The detector including multiple sections may be associated with one of the apertures in at least one electrode of the objective lens assembly. More specifically, the detector 405 including multiple sections may be arranged around a single aperture 406, such as Figure 5A and Figure 5B As shown, they provide examples of such detectors.

[0065] The parts of the partitioned detector can be separated in various ways, such as radially, annularly or in any other suitable way. It is desirable that the parts have similar angular size and / or similar area and / or similar shape, such as Figure 5B As shown. The separated parts can be arranged as multiple segments, multiple annular parts (e.g., multiple concentric rings or annuli) and / or multiple sector parts (i.e., radial parts or sectors). The detector elements 405 can be divided radially. For example, at least one detector 405 can be arranged as an annular part including 2, 3, 4 or more parts. More specifically, as Figure 5A As shown, the detector 405 may include an inner annular portion 405A surrounding the aperture 406 and an outer annular portion 405B radially outward of the inner annular portion 405A. Alternatively, the detector element 405 may be divided by angle. For example, the detector may be arranged in sector-shaped portions, including 2, 3, 4 or more portions, such as 8, 12, etc. If the detector is arranged in two sectors, each sector-shaped portion may be a semicircle. If the detector is arranged in four sectors, each sector-shaped portion may be a quadrant. This is Figure 5B As shown in FIG. 405 , 405 is divided into quadrants, i.e., four sector-shaped parts such as Figure 5B As shown, as described below. Alternatively, the detector may be provided with at least one segmented portion. The electrode elements may be radially and angularly spaced (eg in a dart board arrangement) or spaced in any other convenient manner.

[0066] Each part can have a separate signal readout. It is beneficial to divide the detector into multiple parts (e.g., annular parts or fan-shaped parts) because it allows to obtain more information related to the detected signal particles. Therefore, providing multiple parts for detector 405 may be beneficial to obtain additional information related to the detected signal particles. This can be used to improve the signal-to-noise ratio of the detected signal particles. However, there is additional cost in terms of the complexity of the detector.

[0067] like Figure 5A As shown, the detector includes an inner detection portion 405A and an outer detection portion 405B, wherein an aperture 406 for passing a charged particle beam is defined and configured. The inner detection portion 405A surrounds the aperture 406 of the detector. The outer detection portion 405B is radially outside the inner detection portion 405A. The shape of the detector can be roughly circular. Therefore, the inner detection portion and the outer detection portion can be concentric rings. In one example, the detector can be divided into two (or more) concentric rings, for example, Figure 5A shown.

[0068] Providing multiple sections in a concentric manner or otherwise may be beneficial because different sections of the detector may be used to detect different signal particles, which may be smaller angle signal particles and / or larger angle signal particles, or secondary signal particles and / or backscattered signal particles. This configuration of different signal particles may be suitable for a concentric partitioned detector. Backscattered signal particles at different angles may be beneficial in providing different information. For example, for signal particles emitted from a deep hole, small angle backscattered signal particles may come more from the bottom of the hole, while large angle backscattered signal particles may come more from the surface and material around the hole. In an alternative example, small angle backscattered signal particles may come more from deeper buried features, while large angle backscattered signal particles may come more from the sample surface or the material above the buried feature.

[0069] Any suitable variation in the arrangement may be implemented. For example, the macro collimator may be partially or completely replaced by an array of collimator elements disposed downstream of the upper beam limiter. For example, a macro scanning deflector 265 may be provided to allow the beamlets to be scanned over the sample 208. For example, the macro scanning deflector 265 may be partially or completely replaced by an array of scanning deflectors.

[0070] In other embodiments, both the macro-scanning deflector 265 and the scanning deflector array are provided. In such an arrangement, scanning of the beamlets over the sample surface can be achieved by controlling the macro-scanning deflector and the scanning deflector array 260 together (desirably synchronously).

[0071] The present invention is applicable to a variety of different tool architectures. For example, the charged particle beam tool 40 can be a single beam tool, or can include multiple single beam device columns (or single beam devices 41), or can include multiple multi-beam device columns (i.e., sub-beams). These device columns can include, or even the charged particle optical device 41 described in any of the above embodiments or aspects. As multiple device columns (or multi-device column tools), these devices can be arranged in an array, and the number can be two to one hundred columns or more. The charged particle optical device can be a charged particle optical device column. The charged particle device column can optionally include a source.

[0072] If multiple detector arrays are provided, they can be configured to detect signal particles simultaneously. The detector can be positioned to face upstream of the primary beam path 320. In other words, the detector can be configured to face the source of the primary beam (described above as source 201) along the primary beam path 320, i.e., away from the sample 208. The detector can be configured to face the sample, i.e., in the direction of the sample 208. In other words, the detector can face the sample 208 in the direction along the primary beam path 320, i.e., away from the source.

[0073] Any detector array may be associated with (e.g., located in, on, near, connected to, or integrated with) at least one electrode (e.g., an upstream electrode or a downstream electrode) of the objective lens array 241. For example, the detector array may be located in or on at least one electrode of the objective lens array 241. For example, the detector array may be located near one of the electrodes. In other words, the detector array may be positioned closely adjacent to or near one of the electrodes. For example, the detector array may be connected (e.g., mechanically connected) to one of the electrodes. In other words, the detector array may be attached to one of the electrodes, such as by an adhesive or welding or some other attachment method. For example, the detector array may be integrated with one of the electrodes. In other words, the reflector detector array may be formed as part of one of the electrodes.

[0074] like Fig. 6A As shown, the surface of the detector array or detector module (preferably facing the sample, or even close to the sample when in use) has an array of detector elements (or detector array). Each detector element is associated with an aperture. Each detector element is associated with an allocated surface area of ​​the substrate of the detector module. Since the substrate is layered, such as with a CMOS structure, each layer within the substrate is positioned relative to the corresponding detector element, and it is expected to be positioned closely. Commercially available CMOS structures have a usual range of layers, such as three to ten, typically about five. (For example, for ease of description, two functional layers can be provided, which can be called circuit system layers. These two wiring layers and logic layers can represent the required number of layers, and each layer is not limited to wiring or logic.) The number of layers is limited by commercial availability, and any number of layers is feasible. However, from a practical point of view, the substrate has a limited number of layers, and the available space is limited in order to achieve an effective design.

[0075] Ideally, a circuit layer of the substrate (which may be a wiring layer and / or a logic layer) has a portion allocated for each detector element (or detector). The allocated portions of the different layers may be referred to as cells 550. The arrangement of the portions in the substrate for a full multi-beam arrangement may be referred to as a cell array 552. The shape of the cells 550 may be the same as the surface area allocated to each detector element, such as a hexagon, or any reasonable shape that can be tessellated together and are similar in shape and / or area, such as a rectangle. Rectangular or rectilinear shapes may be more easily used by a place and route design. Such a design is typically implemented by software adapted to define chips with rectangular type architectures having orthogonal directions, rather than architectures requiring sharp or obtuse angles, such as a hexagonal architecture. In Fig. 6A, the cell 550 is depicted as a hexagon and the cell array 552 is depicted as a hexagon including individual cells. However, ideally, each cell is similarly positioned relative to the detector element. A routing line 554 may be connected to each cell 550. The routing line 554 may be routed between other cells of the cell array 552. Note: With respect to routing lines between array cells, at least the routing lines should avoid the beam aperture of the aperture array, e.g., the beam aperture defined by the cell array. In arranging the circuit architecture, at least the cell size in the circuit layer may be reduced to accommodate the routing lines so that the routing lines may be routed between cells. Additionally or alternatively, the routing lines pass through the cells of the cell array, preferably toward the periphery of the cell, e.g., to reduce interference of the routing with other circuit systems in the cell. Thus, references to routing lines between cells encompass: routing lines between the circuit systems of the cells, routing lines within the cells, desirably toward the periphery of the cells and at least around the beam aperture passing through the cells, and any intermediate variations. In all of these arrangements, such as in a CMOS architecture, the wiring lines can be located in the same die as other circuitry that can define circuitry in the same cell as part of the wiring route, or circuitry in a cell around which the wiring route is routed as part of the wiring route. Thus, the cell and the wiring route can be part of a monolithic structure. The wiring route 554 can signal connect the cell. Thus, the wiring route connects the cell 550 signal to a controller or data processor external to the cell array, or even to a substrate or detector module. The circuit layer can include a data path layer for transmitting sensor signals from the cell in the cell array to the outside.

[0076] The controller or data processor may be located before the circuit system within the substrate or detector module, and is preferably located outside the cell array, such as a control and I / O circuit system (not shown). The control and I / O circuit system may be located in the same tube core as the cell array; the control and I / O circuit system may be monolithically integrated with the cell array, such as in the same CMOS chip. The control and I / O circuit system enables data between all cells of the cell array 552 to be effectively connected. For example, consider an arrangement of about 3,000 cells, each with an 8-bit digital output. This arrangement will send about 22,000 signals to an electronic device located outside the CMOS chip. The standard way to do this is to use a SERDES circuit system (serializer / deserializer). This circuit system will convert a large number of low data rate signals into a small number of high data rate signals through time division multiplexing. Therefore, it is beneficial to integrate the control and I / O circuit system with the cell array monolithically, or at least in the detector module, rather than outside the detector module.

[0077] In an embodiment, the control and I / O circuitry may have general support functions, such as circuitry to communicate with electronics external to the CMOS chip so that certain settings can be loaded, for example for controlling amplification and offset (such as subtraction described herein).

[0078] The circuit layer of unit 550 is connected to the detector element of the corresponding unit. The circuit layer includes circuit systems with amplification and / or digitization functions, for example, it can include amplifier circuits. Such circuit systems associated with the detector (for example, in the unit) can include elements for processing detection signals detected by the corresponding detector elements. Such circuit systems can be regarded as processing detection signals. Such circuit systems can be referred to as detector processing circuit systems. Unit 550 can include a transimpedance amplifier (TIA) 556 and an analog-to-digital converter (ADC) 558, such as Figure 6B 560. The unit may include detector processing circuitry associated with the detector element. The figure schematically depicts a unit 550 with associated detector elements such as capture electrodes and feedback resistors 562 connected to a transimpedance amplifier 556 and an analog-to-digital converter 558. A digital signal line 559 from the analog-to-digital converter 558 leaves the unit 550. Note that the detector element is represented as detector element 560 and the feedback resistor is shown as being associated with the detector area as a disk 562 rather than being associated with the transimpedance amplifier 556. The schematic represents each of the detector element and the feedback resistor as an area to indicate their relative sizes.

[0079] The transimpedance amplifier may include a feedback resistor Rf 562. The magnitude of the feedback resistor Rf should be optimized. The larger the value of this feedback resistor, the lower the input referred current noise. Therefore, the signal-to-noise ratio at the output of the transimpedance amplifier is better. However, the larger the resistor Rf, the lower the bandwidth. The limited bandwidth results in limited rise and fall times of the signal, resulting in additional image blur. An optimized Rf can achieve a good balance between noise level and additional image blur.

[0080] To achieve the design, the circuitry associated with each detector element, i.e., the amplification circuitry, should be located within the layer of the associated cell 550 and fit into the limited available area of ​​the portion of each relevant layer. The typical resistance of the feedback resistor Rf can be as high as 30 to 300 MOhm. If such a resistor is implemented as a polysilicon resistor in a standard CMOS process, the size of such a resistor will be much larger than the area available in the CMOS layer of the cell 550. For example, a 300 MOhm resistor will consume approximately 500,000 microns^2. This is approximately 130 times the total available area.

[0081] Typically, such a large resistor would be made in a single layer, such as polysilicon, for example in a CMOS architecture. Typically there would be only a single layer of polysilicon. In some cases, a layer of material capable of providing a high resistance value may be provided and the reliability of the resistor may remain despite such a high aspect ratio (e.g. the extreme length of the resistive structure in the layer relative to the width). Even if the cell had multiple layers for such a resistor, there would have to be many more layers than are readily available using, for example, CMOS technology. Additionally or alternatively, the high aspect ratio is not mitigated by the winding paths through the different layers and the risk of resistance value variation is only caused by the interconnections between the different layers. Such interconnections affect the variability of the resistance value of the resistor as a corner, as described later in this document.

[0082] Note that these dimensions are calculated assuming a 180nm technology node. Using the 180nm technology node is preferred over smaller nodes for processing reasons. For example, interconnects in the 180nm node are easier to process.

[0083] Furthermore, if such a resistor is manufactured, the reliability of the resistor specifications and the available space for the resistor may be challenging regardless of the node.

[0084] In a layered structure (such as CMOS) for chip architecture, components and features are defined as structures in the layers. The specifications of the components depend on the material of the layer and the physical properties of the layer, the size of the layer (especially its thickness) and the size of the structure formed in the layer. The resistor can take the form of a long and narrow path, line or wire. Taking into account space limitations, the path can be nonlinear, with corners along its path. For such long components, the width of the path in the layer may vary, for example, by manufacturing tolerances. The corners may provide a greater variation than the linear portion of the path, thereby limiting the accuracy with which the resistor is manufactured to have a specified resistance. Due to the large number of corners and the long length, resistors with this topology may be manufactured with poor reliability, so the resistance of the equivalent resistor in different cells of the cell array may have a larger range.

[0085] Such a resistor structure has a large surface area. Additionally or alternatively, a resistor with such a large surface area may also have undesirable capacitance; such capacitance is called parasitic capacitance. Parasitic capacitance may undesirably cause noise and blurring, affecting the balance between noise, blurring, and bandwidth optimization, which is described elsewhere in this article.

[0086] The material properties of this layer can be modified chemically; however, such modification is unlikely to achieve an improvement in size by several orders of magnitude to fit within the available space in the cell. Such modification is unlikely to change the topology of the feedback resistor sufficiently to have the required specifications and to be manufactured with the required reliable accuracy.

[0087] Such reliability and size requirements would require the resistor to achieve its required performance in terms of bandwidth, signal-to-noise ratio and stability. Unfortunately, these requirements cannot be met.

[0088] Alternative amplification circuit systems are proposed that do not require such large feedback resistors. Examples include direct analog-to-digital converters and transimpedance amplifiers with pseudo-resistors as feedback elements, thereby eliminating the need for transimpedance amplifiers. Two examples of direct analog-to-digital converters are: using low duty cycle switched resistors and using reference capacitors. These examples are described in detail in European application number 20217152.6 (WO2022008462) filed on December 23, 2020, which is incorporated herein by reference, particularly with respect to the use of low duty cycle switched resistors and reference capacitors. An optional arrangement is to remove the analog-to-digital converter 558 from the cell 550 so that the circuit conductor 570 connects the transimpedance amplifier 556 in the cell 550 to the analog-to-digital converter outside the cell array 552, as described in European application number 20217152.6 (WO2022008462) filed on December 23, 2020. By removing the analog-to-digital converter from cell 550, more space is available in the circuit layers of cell 550 for the feedback resistor element. If the amplifier circuitry uses an alternative transimpedance amplifier circuit, for example, if a transimpedance amplifier with a pseudo resistor is used as the feedback element, there is still more space in the circuit layers of cell 550. The example amplifier circuits described are just some suitable types of amplifier circuitry that can be used. There may be other amplifier circuits that achieve similar benefits as described herein and use similar circuit architectures for each cell as described herein.

[0089] Although it may be easier to mount the transimpedance amplifier 556 in the circuit layer of the cell along with the pseudo-resistor feedback element and the analog-to-digital converter, in some arrangements, it is more practical to place the analog-to-digital converter 558 outside the cell array 552 due to space limitations. This provides a gain of one to two orders of magnitude in area despite the use of pseudo-resistors in the feedback elements of the transimpedance amplifier. One consideration in deciding whether the analog-to-digital converter 558 is placed outside the cell array 552 is the sub-beam pitch of the multi-beam. For example, with a sub-beam pitch between 50 and 100 microns, typically only 4000 square microns per cell layer are available for circuits including the amplification circuit system.

[0090] Under this space constraint, the transimpedance amplifier is located in the cell of each beam. The analog-to-digital converter is located outside the array of sub-beams, i.e., outside the cell array. In one embodiment, the analog-to-digital converter is located on the same die as the cell array, for example, monolithically integrated with the cell array. Such an analog-to-digital converter can be located with control and I / O circuitry, which can be located on the detector module or even monolithically integrated with the cell array 552. Locating the analog-to-digital converter outside the cell array can provide an area gain of approximately two times.

[0091] Circuit conductor 570 connects the transimpedance amplifier in unit 550 with the associated analog-to-digital converter 558. Circuit conductor 570 transmits analog signals. Unlike digital signals, the data path for transmitting analog signals is susceptible to interference. Signal interference may come from crosstalk with other circuit conductors and external fields (such as fields generated by sub-beams of a multi-beam) and fields from nearby charged particle optical components (such as objective lens array 241).

[0092] Circuit conductors 570 are routed through routing lines 554, such as Fig. 6A As shown. The wiring lines 554 are routed between the cells so that the area of ​​the cells and their layers is used for the amplification circuit system present on the cells. Therefore, the wiring lines 554 use only a portion of the existing wiring lines of the circuit layer, that is, between adjacent cells 550 (e.g., at least around the beam apertures 504, 406 of adjacent cells 550; through adjacent cells 550, such as toward the periphery of the cells, or between the circuit systems in the layers assigned to adjacent cells 550, or any arrangement between the arrangements). This routing avoids architectural interference between the architectures of the amplification circuit system and the wiring lines 554. The circuit conductors are routed outwardly along the wiring lines in the cell array, such as in a radially outward direction. Because they are closer to the periphery of the cell array 552, there may be more circuit conductors 570 than portions of the wiring lines 554 that are far from the periphery. The wiring lines may have multiple circuit conductors 570, which, as described, are located between the cells of the array. Therefore, a portion of the wiring lines 554 may have more than one circuit conductor 570. However, positioning the circuit conductors close to each other presents a risk of crosstalk occurring between the circuit conductors and interference with the analog signals transmitted by the circuit conductors 570 .

[0093] By shielding the circuit conductors 570 from each other within the wiring lines, the risk of crosstalk and signal interference can be at least reduced or even prevented. Figure 7A cross section of an example arrangement of a wiring line 554 is depicted. Within the wiring line 554 are one or more circuit conductors 470, which are shown extending in the same direction as the wiring line 554 and having a shielding arrangement. The circuit conductors are shown in the same layer. Above the circuit conductor 570 is an upper shielding layer 572; below the circuit conductor 570 is a lower shielding layer 574 (or a further downstream shielding layer 574). The upper and lower shielding layers of the shielding arrangement shield the circuit conductor 570 from fields outside the wiring line 554 above and below the wiring line 554. The shielding arrangement has a shielding element located in the same layer as the circuit conductor 570. The shielding element can be an external element 576 located at the outer edge of the layer including the circuit conductor 570. The external element 576 shields the circuit conductor 570 from fields outside the wiring line 554. The shielding element can include an intermediate shielding element 578 present in a layer between adjacent circuit conductors. Therefore, the intermediate shielding element 578 can at least (if not prevent) suppress crosstalk between the circuit conductors 570. In operation, a common potential is applied to the shielding layers 572, 574 and the shielding elements 576, 578. The potential may be a reference potential, such as ground potential.

[0094] although Figure 7 A three-layer arrangement is depicted, but as many layers as desired may be used in the wiring line 570. For example, there may be two layers of circuit conductors, requiring three shielding layers, including an upper shielding layer 572, a lower shielding layer 574, and an intermediate shielding layer. The intermediate shielding layer may additionally reduce, if not prevent, crosstalk between circuit conductors in different layers of the wiring line 570. Thus, there are five layers in total. Each additional layer of circuit conductors requires an additional intermediate shielding layer. While increasing the number of layers in the wiring line 554 reduces the proportion of layers required for wiring, this design change requires additional layers. Given the finite number of layers, there is an optimal number of layers at which the width of the wiring line is reduced without exceeding the number of layers required elsewhere in the detector module substrate, which can be limited to five layers.

[0095] A further consideration in the design of the wiring circuits is the number of circuit conductors that may need to be present in an exemplary design of the detector module, for example Figure 7 arrangement in which all circuit conductors 570 are in one layer.

[0096] For example, the array of sub-beams is arranged in a hexagonal array, in which there are rings of thirty (30) sub-beams, for example arranged concentrically. Thus, the detector module has a correspondingly designed cell array. The number of cells is about 3000. The pitch of such a cell array can be fifty to two hundred micrometers.

[0097] The outermost ring has the largest number of signals that need to be routed through the ring. Considering that the wiring line is routed between the cells of the cell array, the signals of all cells are routed through the outermost ring, between the cells of the outermost ring. In this example, the outermost ring consists of 180 cells, so the number of signals transmitted through the outermost ring (e.g., between the cells of the outermost ring) is about 2600. Therefore, the maximum number of signals routed through the outer ring between adjacent cells is the total number of signals divided by the number of cells in the outermost ring (e.g., about 180). This is fifteen 15 (rounded to the nearest integer). Since the wiring line has a shielding arrangement to ensure that the signals are well shielded, such as limiting the effects of crosstalk and external fields, there can be sixteen shielding elements, including fourteen (14) intermediate shielding elements and two external shielding elements 576. Therefore, between adjacent cells 550 of the outer ring of the example, the wiring line with all circuit conductors on the same layer will have thirty-one (31) alternating shielding elements and circuit conductor elements.

[0098] For the cell array 552 of the beam array with a pitch between 50 and 100 microns, there is enough space or area in the circuit layer for such a wiring line 554. In the structure created using the process of the 180nm node, the minimum half pitch of the metal layer is usually about 280nm. In this case, the half pitch is the line, and the pitch is the line with an associated gap and an adjacent gap. The associated gap is usually the same as the width of the line. The wiring line of thirty-one elements requires thirty-one pitches. However, the associated gap of one of the elements corresponding to the external element 576 is not part of the wiring line 554, but will separate the wiring line from the adjacent circuit system. Therefore, for thirty-one elements, sixty-one (61) half pitches are required, which corresponds to a width of the circuit wiring 554 of about 17.1 microns.

[0099] By ensuring that the amplification factor of the transimpedance amplifier is programmable, an optimization of the noise performance can be achieved, for example in terms of bandwidth and noise optimization and the balance between blur and noise. In this arrangement, the amplifier circuit of the unit, at least the transimpedance amplifier, is programmable. Such a programmable amplification circuit may include a variable amplifier and / or a variable analog-to-digital converter, for example in terms of its sensitivity. The variable amplifier has a variable amplification range that depends on the detection beam current detected by the detector element 503. For example, when the detection beam current is low, or for samples with a lower than typical secondary emission coefficient, the variable amplifier can be adjusted to provide a larger amplification than is normally used. When the detector element 503 detects a larger beam current than normal, or for samples with a higher than typical secondary emission coefficient, the variable amplifier can be adjusted to provide a smaller amplification.

[0100] This functionality is beneficial for a transimpedance amplifier having a feedback element with a pseudo-resistor. A pseudo-resistor has different effective resistances when different applied voltages are applied; unlike an ideal resistor, which has a single resistance at all applied potential differences. When providing different resistances, the transimpedance amplifier associated with the pseudo-resistor acts as a variable amplifier. When providing an amplifier with a variable function, an optimized balance between noise level and image blur (referred to herein above as "additional blur") can be achieved. Advantageously, the programmable amplification circuit can match the output of the transimpedance amplifier to the input of the analog-to-digital converter. This can be a programmable offset subtracted between the output of the transimpedance amplifier and the input of the analog-to-digital converter. The programmable offset can help reduce the required number of bits that need to be transmitted from the amplification circuit of the unit. The programmable offset can be implemented in a programmable amplifier. These measures help ensure that the dynamic range of the transimpedance amplifier and the analog-to-digital converter, and therefore the desired amplification circuit, is optimally used in different use cases. These different use cases may include: material properties of the sample under inspection, different evaluation tool configurations (e.g., using different beam currents). A range of applications can be achieved by providing a variable amplifier and a variable offset or threshold (e.g., by subtracting a programmable offset), with the expectation of being able to adjust amplification, threshold, and bandwidth. As described elsewhere herein, circuitry associated with variable amplification and subtraction can be included in control and I / O circuitry.

[0101] In known systems, primary charged particles are projected onto a sample (e.g., a wafer) through a set of lenses and detectors, such as described above. Signal charged particles emitted from the sample due to the incidence of the primary charged particles on the sample surface can be detected by the detector, which can convert the detection of the charged particles into an electrical signal. The electrical signal can be converted into an image of the substrate. Desirably, the charged particle detector is positioned near and parallel to the sample surface, for example, on the order of microns. In order to ensure that the charged particle detector remains at a suitable and safe level above the sample, at least one distance sensor can be used to measure the distance between the sample and the charged particle detector surface. The distance sensor can be referred to as a z sensor, referring to the axis of a coordinate system typically used to measure the distance between the sample and the charged particle detector.

[0102] In known systems, at least one distance sensor is implemented as part of at least one additional module having its own mechanical housing and its own readout electronics. Housing the distance sensor near and around the charged particle detector takes up valuable space in critical areas around the charged particle detector and above the sample. This limits the implementation of other systems or other detectors near the charged particle detector. Furthermore, since the distance sensor is a mechanically separate component, precise alignment and mechanical tolerance control between the distance sensor and the charged particle detector are additional requirements that need to be met in production and assembly.

[0103] In one embodiment, a sensor substrate for a charged particle evaluation device is provided, such as Figure 8 The sensor substrate 700 may also be referred to as a detector chip, or if it has Fig. 6A , Figure 6B and / or Figure 7 The CMOS structure can be called a CMOS detector chip.

[0104] The sensor substrate 700 includes a plurality of distance sensors 701. Each distance sensor 701 is configured to generate a measurement signal representing the distance between the distance sensor 701 and a facing surface of a target. Thus, the distance sensor 701 can be used to measure the distance to a target. Desirably, the target is Fig. 9 Sample 208 shown.

[0105] Providing the distance sensor 701 as part of the sensor substrate 700 means that the distance sensor 701 is incorporated into the sensor substrate 700 and is part of the sensor substrate 700. Therefore, the constituent features (i.e., components) of the distance sensor 701 can be provided within the sensor substrate 700, i.e., within the structure of the sensor substrate 700. For example, as further described below, any isolation and / or circuit elements that may be part of the distance sensor 701 can be formed within the sensor substrate 700, or at least formed as part of the sensor substrate 700. The sensing substrate 700 may include several components (e.g., several components), but may be a single monolithic structure. Therefore, the components of the sensor substrate 700 may be integrated with the structure, i.e., incorporated into the structure.

[0106] Since the distance sensor 701 is part of the sensor substrate 700, the distance measurement function can be integrated into the sensor substrate 700 itself. In this way, the output of the sensor substrate 700 can directly include the output of the distance sensor 701, thereby eliminating the need for a separate distance sensor. This distance sensor 701 integrated into the sensor substrate 770 avoids having a separate distance sensor. This separate distance sensor will be separated from the sensor substrate, other distance sensors or the sensor substrate and another distance sensor, for example, spaced apart. This separate distance sensor is a separate component. As a separate component, it is assembled separately into the device or even the charged particle device 41. The precise relative position of this separate distance sensor relative to another distance sensor or sensor substrate depends on the positioning of the separate distance sensor during assembly. Therefore, in different implementations (e.g., charged particle devices or equipment), there are changes in the positioning of the separate distance sensor relative to another distance sensor and the sensor substrate. This change needs to be calibrated during the setup. Integrating one or more distance sensors into the sensor substrate, or integrating multiple distance sensors into a common substrate, can reduce the required calibration, as described herein.

[0107] The sensor substrate 700 may also include at least one signal detector 710 configured to detect signal particles emitted from the sample 208. As explained further below, the signal detector 710 is a type of charged particle optical component and may be substituted for or used in combination with other types of charged particle optical components.

[0108] Due to being integrated in the sensor substrate 700, the functional areas of the sensor substrate 700 (e.g., including the charged particle detector 710 described further below) are already aligned with the functional areas of the distance sensor 701 in the same substrate. In other words, the charged particle detector 710 and the distance sensor 701 can be arranged in the same mechanical housing. This reduces or eliminates any need to align and / or calibrate the mechanical positioning of the charged particle detector 710 and the distance sensor 701 during production and / or operation.

[0109] The distance sensor 701 is integrated into the sensor substrate 700, allowing the charged particle device 41 (e.g., for an evaluation device used as a microscope, which may be referred to as a microscope lens) to have a smaller base or surface, such as a smaller cross-sectional area. The reduction in the base may contribute to the future feasibility of a multi-device evaluation device, for example, which may be referred to as a multi-device column microscope. In such a multi-device architecture, multiple charged particle devices simultaneously and in parallel direct multiple charged particle beams to the sample. Therefore, multiple microscope lenses can operate on a sample at the same time, thereby increasing the evaluation throughput.

[0110] Since the distance sensors 701 and the signal detectors 710 are provided as part of the sensor substrate 700, the thermal expansion of the sensor substrate 700 may be the same. Therefore, the thermal expansion generally varies consistently throughout the sensor substrate 700, desirably more consistently than in an arrangement where the distance sensors are separate from the signal detectors. This is beneficial because the thermal expansion can be characterized over the thermal range of all of the distance sensors 710 and the signal detectors 701 (which may be part of the sensor substrate 700). This reduces the likelihood that some sensors will move relative to other sensors, which may be more likely to occur if the sensors and detectors are mounted separately in the evaluation device 40, for example, mounted to different components or housings.

[0111] The signal detector 710 may be a charge type detector, such as Figure 8 and Fig. 9 As shown, the charge-type detector 710 may be formed by a metal layer on the surface of the sensor substrate 700 .

[0112] Desirably, at least one aperture 711 is defined through the sensor substrate 700 to pass at least one beam toward the sample 208 and / or sample location. During operation, the sensor substrate 700 may be positioned such that the aperture 711 is aligned along the primary beam path 320 .

[0113] If at least Figure 8 and Fig. 9 As shown, the signal detector 710 may be associated with the aperture 711. The aperture may be defined in the substrate 700, desirably in the signal detector 710. The signal detector 710 may be positioned around the aperture 711. The signal detector may include a detector surface, desirably substantially annular. The signal detector 710 may be provided as a single part (e.g., a single electrode). Alternatively, the signal detector 710 (desirably a detector surface) may include multiple parts arranged around a single aperture 711, for example, as described above with respect to Figure 5A and Figure 5B described.

[0114] The sensor substrate 700 may be formed of any suitable material, and by way of example only, the sensor substrate may be formed of silicon, and thus the bulk (ie, structure) of the sensor substrate 700 may be silicon.

[0115] The distance sensors 701 are desirably positioned near the signal detector 710. The distance sensors 701 may be positioned around the signal detector 710. Thus, the distance sensors 701 may all be located radially outward of the signal detector 710, i.e., further away from the aperture 711 than the signal detector 710. Desirably, the plurality of distance sensors 701 are equidistant from the origin. For example, the distance sensors 701 may each be positioned at the same distance from the center of the aperture 711, which is desirably the location of the primary beam path 320 during operation. Desirably, adjacent distance sensors 701 are separated by similar distances, such as Figure 8 In other words, the distance sensors 701 may be equally spaced from each other. Desirably, the distance sensors 701 are positioned around the edge of the sensor substrate 700, such as Figure 8 As shown, i.e., towards the periphery of the sensor substrate 700. However, this is not required, and the distance sensors 701 may be positioned in any suitable position or configuration. By way of example only, the distance sensors 701 may be interleaved with other components / parts, one or more of which may be desirably located in a non-beam region between other components or parts, and other components or parts in a region corresponding to the path of the beam through the components or parts, which may be referred to as a "beam region". For example, as described in US2012 / 0305798 Figure 1 and at least one of Figures 21, 22, or 23 of EP A20213733.7 filed on December 14, 2020, which discloses staggered group positions of sub-beam processing areas and unfilled footprint portions (rather than non-beam and beam areas). US2012 / 0305798 and the EP application are incorporated herein by reference at least for the disclosures regarding beam areas and non-beam areas (or equivalent features). For example, the distance sensor 701 can be staggered with the signal detector 710, for example in a multi-device arrangement, which desirably enables one sensor substrate to be used for multiple devices (device columns), enabling the devices to be positioned closer together with a smaller pitch. If the substrate 700 contains a larger array of signal detectors 710 in a relatively large area, this may be useful because the staggered distance sensors 701 can be used to measure the distances of each point within the array. This situation can be applied to a multi-device column (or multi-charged particle device) arrangement.

[0116] like Fig. 9As shown, when the sensor substrate 700 is positioned for operation (e.g., so as to generate a measurement signal representing the distance between the distance sensor 710 and the facing surface of the target), the sensing surface 721 of the distance sensor 701 (an example of which may be referred to as the main surface of the distance sensor 701) and the detection surface 722 of the signal detector 710 (an example of which may be referred to as the main surface of the signal detector 710) may be configured to face the sample 208 (or any suitable target). The sensor substrate 700 may be in an operational state when positioned in and as part of a larger device 41 or device 40. Desirably, the sensing surface 721 and / or the detection surface 722 provide at least a portion of the base of the charged particle optical device 41. The sensing surface 721 of the distance sensor 701 and the detection surface 722 of the signal detector 710 may be parallel to each other. Desirably, the sensing surface 721 of the distance sensor 701 and the detection surface 722 of the signal detector 710 are located in the same plane. Since the sensing surface 721 of the distance sensor 701 is aligned with the detection surface 722 of the signal detector 710, the distance between the distance sensor 701 and the sample 208 can be smaller. Since the distance noise increases with the square of the distance, providing a substrate that can achieve a smaller distance can reduce the distance measurement noise. When the ratio of noise to measurement signal in the distance measurement is low (or small), lower distance measurement noise can be achieved. In more detail, since the distance sensor 701 and the signal detector 710 are integrated in the substrate, the total tolerance chain can be reduced. In other words, these components can be positioned more accurately. In turn, this means that the components can be positioned closer to the target, that is, the distance between the distance sensor 701 and the sample 208 can be smaller.

[0117] The sensing surface 721 of the distance sensor 701 may be at least a portion of a main plane of the sensor substrate 700. In other words, the sensing surface 721 of the distance sensor 701 may form at least a portion of the outermost surface of the sensor substrate 700. Additionally, the sensing surface 721 of the distance sensor 701 may be planar, i.e. flat. The sensing surfaces 721 of all distance sensors 701 may be located in the same plane. As described above, the detection surface 722 of the signal detector 710 may be located in the same plane as the sensing surface 721 of the distance sensor 701. Therefore, the detection surface 722 of the signal detector 710 may also form a portion of the main plane of the sensor substrate 700.

[0118] The sensor substrate 700 may include circuitry (as shown and referenced herein). FIG. 6A to FIG. 7The circuit system may be associated with the distance sensor 701 and / or the signal detector 710. Desirably, the sensor substrate 700 includes a circuit system configured to process a detection signal generated by the signal detector 710. Additionally or alternatively, the sensor substrate 700 includes a circuit system configured to process a measurement signal from the distance sensor 701. The circuit system (associated with either or both of the distance sensor 701 and / or the signal detector 710) may be positioned in any suitable location. For example, the circuit system may be partially or entirely included in the insulating element 730 (which may be provided as an insulating layer) and / or the circuit system may be partially or entirely included in the circuit system layer 720.

[0119] The sensor substrate 700 may include an isolation element 730. As will become apparent below, the isolation element 730 may provide at least a portion of the distance sensor 701. Additionally or alternatively, the isolation element 730 may provide at least a portion of the signal detector 710. The isolation element 730 may be provided as a plurality of isolation portions, or as a single integral portion or component. The isolation element 730 may be provided as an isolation layer, such as Fig. 9 The isolation element 730 may be provided as an isolation film.

[0120] like Fig. 9 As shown, the isolation element 730 can be part of the distance sensor 701, that is, the distance sensor 701 desirably includes at least a portion of the isolation element 730. At least a portion of the distance sensor 701 can be supported by the isolation element 730. Each distance sensor 701 may include a sensing electrode 704. The sensing electrode 704 may be supported by the isolation element 730. Therefore, the sensing electrode 704 may be positioned on the sensor substrate 700 and connected to the sensor substrate 700 by the isolation element 730. Other component features of the distance sensor 701 (for example, if other electrodes are provided) may also be supported by the isolation element 730. The arrangement of the distance sensor 701 with at least another electrode can provide a differential distance sensor. In other words, the distance sensor 701 can be a differential sensor. The differential distance sensor has at least two electrodes for distance measurement (that is, at least two sensing electrodes). Therefore, each distance sensor 701 may include two sensor elements, desirably configured to perform differential measurements relative to each other. Distance measurement using a differential distance sensor is based on signals generated by each of two electrodes, as disclosed in US 2011 / 0261344, the disclosure of which is incorporated herein by reference with respect to differential sensors. Electrodes of distance sensor 701, such as sensing electrode 704 (which may provide sensing surface 721), may be configured to face a target (during operation), such as Fig. 9 As shown. Fig. 9, the distance sensor 701 is shown as being positioned on a flat surface of the isolation element 730. It is understood that the distance sensor 701 may be disposed in a recess in the isolation element 730 such that the main surface of the isolation element and the sensing surface 721 of the distance sensor 701 may be disposed in the same plane, i.e., at the same level. In other words, at least a portion (or isolation feature) of the isolation element 730 or at least one ground electrode may be positioned between the distance sensor 701 and / or the signal detector 710, and / or between constituent features of the distance sensor 701 and / or the signal detector 710.

[0121] although Fig. 9 An integrated isolation element 730 is shown used throughout the sensor substrate 700, but this is not required, and a portion of the isolation element can be associated with a distance sensor 701 that is separate from at least one other portion of the isolation element. Each distance sensor 701 can have its own isolation element portion. In this case, each distance sensor 701 desirably has its own isolation element portion in the isolation layer. Therefore, the portion of the isolation element 730 associated with each distance sensor 701 is desirably arranged in a plane. Ideally, the shape of each portion of the isolation element associated with one of the distance sensors 701 corresponds to the shape of that distance sensor 701. For example, if the distance sensor 701 is substantially square in plane (such as Figure 8 ), the portion of the isolation element associated with the distance sensor 701 may also be substantially square and have similar planar dimensions. The shape of the isolation element may be substantially concentric with the shape of the distance sensor 701.

[0122] The circuitry may provide at least a portion of the distance sensor 701. Additionally or alternatively, the circuitry may provide at least a portion of the signal detector 710. At least a portion of the circuitry of the sensor substrate may be positioned in the isolation element 730.

[0123] Desirably, the circuitry in the portion of the isolation layer associated with at least one distance sensor 701 is the circuitry of at least one distance sensor 701. In other words, the circuitry that is part of the distance sensor 701 can be located in the isolation element. In addition, if only a portion of the isolation element is associated with the distance sensor 701, desirably, that portion of the isolation element includes the circuitry associated with the corresponding distance sensor 701. For example, Fig. 9 Vias 705 and 706 (ie, electrical connectors) are depicted from distance sensor 701 to circuitry layer 720. Additional portions of circuitry associated with distance sensor 701 may be disposed in the isolation element.

[0124] like Fig. 9As shown, the isolation element 730 can be part of the signal detector 710, that is, the signal detector 710 preferably includes at least a portion of the isolation element 730. At least a portion of the signal detector 710 can be supported by the isolation element 730. Each signal detector 710 can include a detection electrode (e.g., the above-mentioned metal layer). The detection electrode can be supported by the isolation element 730. Therefore, the signal detector 710 can be positioned on the sensor substrate 700 and connected to the sensor substrate 700 through the isolation element 730. Other component features of the signal detector 710 (e.g., other electrodes if provided) can also be supported by the isolation element 730. The detector electrodes of the signal detector 710 can be configured (during operation) to face the target, such as Fig. 9 As shown. Fig. 9 , the signal detector 710 is shown as being positioned on a flat surface of the isolation element 730. It is understood that the signal detector 710 can be disposed in a recess of the isolation element 730 such that the main surface of the isolation element and the detection surface 722 of the signal detector 710 can be disposed in the same plane, i.e., at the same level. In other words, at least a portion (or isolation feature) of the isolation element 730 or at least one ground electrode can be positioned between the distance sensor 701 and / or the signal detector 710, and / or between constituent features of the distance sensor 701 and / or the signal detector 710.

[0125] exist Fig. 9 In the arrangement shown, the detection surface 722 of the signal detector 710 is located in the same plane as the sensing surface 721 of the sensor 701. However, this is not required. Alternatively, in any embodiment or variation described herein, the sensing surface 721 may be lower than the detection surface 722, for example, closer to the sample position. Alternatively, in any embodiment or variation described herein, the sensing surface 721 may be higher than the detection surface 722, for example, farther away from the sample position. As described herein, at least a corresponding portion of the isolation surface 731 of the isolation element may be located in the same or different plane as the detection surface 722, the sensing surface 721, or both.

[0126] like Fig. 9 As shown, the isolation element 730 may be shared by the distance sensor 701 and the signal detector 710. Therefore, the distance sensor 701 and the signal detector 710 may use the same isolation element 730, that is, an integral isolation element may be used for the sensor substrate 700.

[0127] although Fig. 9It is shown that an integrated isolation element will be used for the sensor substrate 700, but this is not required, and a portion of the isolation element can be associated with a signal detector 710 that is separate from at least one other portion of the isolation element. Each signal detector 710 can have its own isolation element portion. In this case, each signal detector 710 desirably has its own isolation element portion in the isolation layer. Therefore, the portion of the isolation element 730 associated with each corresponding signal detector 710 is desirably arranged in a plane. The portion of the isolation element associated with at least one signal detector 710 can be located in the same plane as at least one or all portions of the isolation element associated with at least the distance sensor 701. Desirably, each portion of the isolation element associated with one of the signal detectors 710 corresponds in shape to the shape of the signal detector 710. For example, if the signal detector 710 is substantially circular in plane (such as Figure 8 As shown), the portion of the isolation element associated with the signal detector 710 may also be substantially circular and have similar dimensions in a plane.

[0128] Desirably, the circuitry in the portion of the isolation layer associated with at least one signal detector 710 is the circuitry of at least one signal detector 710. In other words, the circuitry that is part of the signal detector 710 can be located in the isolation element. If only a portion of the isolation element is associated with the signal detector 710, desirably, that portion of the isolation element includes the circuitry associated with the corresponding signal detector 710. For example, Fig. 9 Vias 707 (ie, electrical connectors) are depicted from signal detector 710 to circuitry layer 720. Additional portions of the circuitry associated with signal detector 710 may be provided in the isolation element.

[0129] although Fig. 9An integrated circuit system layer 720 is shown to be used throughout the sensor substrate 700, but this is not required. A portion of the circuit system may be associated with a distance sensor 701 that is separate from at least one other portion of the circuit system. A portion of the circuit system may be associated with a signal detector 710 that is separate from at least one other portion of the circuit system. Thus, the circuit system may be provided as multiple circuit system portions, or as a single integrated portion or component. In either case, the circuit system may be included in the circuit system layer 720 of the sensor substrate. Desirably, the circuit system in a portion of the circuit system layer 720 associated with each distance sensor 701 and / or signal detector 710 is the circuit system of each distance sensor 701 and / or signal detector 710, respectively. Desirably, the shape of each portion of the circuit system layer associated with one of the distance sensors 701 corresponds to the shape of the distance sensor 701. For example, if the distance sensor 701 is substantially square in plane (e.g., Figure 8 ), the portion of the circuit system layer associated with the distance sensor 701 may also be substantially square and have similar dimensions in plan. Desirably, the shape of each portion of the circuit system layer associated with one of the signal detectors 710 is similar to or even corresponds to the shape of the signal detector 710. For example, if the signal detector 710 is substantially circular in plan (e.g. Figure 8 ), the portion of the circuitry layer associated with the signal detector 710 may also be substantially circular and have similar dimensions in a plane. The circuitry portion associated with a feature of the sensor substrate 700 (e.g., a portion of the circuitry layer within the sensor substrate) may have the same shape and dimensions as the shape of the feature in the plane of the sensor substrate 700.

[0130] Although the circuit system layer 720 is shown as part of the sensor substrate 700, additionally or alternatively, at least one circuit system layer may be present in an associated substrate, for example, for processing the detection signal. Such an associated substrate may be arranged according to the circuit layer in the sensor substrate. The associated substrate may be fixed to the sensor substrate 700, for example, with solder balls. Such additional substrates can be used in known detector architectures and can be used in addition to or alternatively to the circuit system layer 720 in the embodiments and variants described herein.

[0131] Desirably, the circuitry in the circuitry layer 720 is connected to the distance sensor 701 and / or the signal detector 710 through at least a portion of the isolation element. The circuitry layer may be electrically connected to all distance sensors 701 and signal detectors 710 provided. Such connections between layers may be vias (e.g., through silicon vias) extending through one or more layers of the sensor substrate.

[0132] Sensor 701 may be a capacitive sensor. Typically, a capacitive sensor may be used by detecting a change in capacitance between sensing electrode 704 and a target caused by a change in the distance between sensing electrode 704 and the target. This is described in detail in US2011 / 0261344, which is incorporated herein by reference. By way of example only, distance sensor 701 may be a differential distance sensor as described above, and may be provided with at least two sensing electrodes to provide such a capacitive sensor.

[0133] An advantage of a capacitive sensor is that it can provide a measurement of the distance to a target (e.g., the distance between two adjacent surfaces) with sufficient accuracy. Each capacitive sensor may include a sensing electrode 704, which is a conductive sensing electrode. The capacitance is proportional to the area of ​​the sensing surface and inversely proportional to the distance between the sensing surface and the target. If the distance to the target is smaller, the area of ​​the sensing surface may also be smaller while still having the same capacitance. By way of example only, the area of ​​the major surface of the sensing electrode (i.e., an example of a sensing surface) may be of any suitable size. The area may be at least several mm 2 , for example at least about 1 mm 2 , at least about 5mm 2 , or at least about 10mm 2 or more. The area can be less than 5mm 2 , or it can be larger, for example, the area can be tens of mm 2 , or at least 1cm 2 , or a few cm 2 , or tens of cm 2 The area can be about 5mm 2 Up to 100mm 2 , or preferably 10mm 2 Up to 50mm 2 In general, capacitance is linearly related to electrode area, so providing a sensing electrode of this size provides sufficient capacitance to accurately measure, for example, the distance between the electrode and a facing surface of the stage (such as a sample). Figure 8 and Fig. 9 , but can be set to any shape.

[0134] Desirably, each capacitive sensor includes a guard electrode 703, which is a conductive guard electrode. The guard electrode 703 may be disposed on the side of the sensing electrode 703 in cross section. The guard electrode 703 may preferably be as follows: Figure 8As shown, the sensing electrode 704 is surrounded on a plane. The sensing electrode 704 and the guard electrode 703 may be positioned on at least a portion of the isolation element 730 (as described above). There may be a gap between the sensing electrode 704 and the guard electrode 703, that is, the sensing electrode 704 and the guard electrode 703 are not in contact. The gap is preferably narrow and may be an air gap or may include at least a portion of the insulating element 730. The guard electrode 703 may be set to the same potential as the sensing electrode 704 that it surrounds.

[0135] In the absence of a guard electrode, the electric field between the sensing electrode 704 and the target may bend at or near the edge of the sensing electrode. The sensing electrode 704 may be susceptible to parasitic capacitance. If there is a conductor near the edge of the sensing electrode 704, this will affect the electric field, which in turn affects the measurement signal generated by the distance sensor 701. Since a guard electrode 703 is provided around the sensing electrode 704, and the guard electrode 703 is set to have the same potential as the sensing electrode 704, these problems can be reduced or avoided. The guard electrode 703 can improve the predictability of the distance measurement and make it easier to model the measurement signal. Therefore, the guard electrode 703 can be used as a shield against external interference. The guard electrode 703 can help reduce or avoid the influence of the electric field bending in the area between the sensing electrode 704 and the target, thereby reducing or even avoiding parasitic capacitance.

[0136] Optionally, each capacitive sensor may include a rear guard electrode (not shown). The rear guard electrode may be positioned on the isolation element, preferably on the back side (or upstream surface) of the insulating element 730, i.e., on the side of the isolation element 730 opposite to the isolation surface 731 where the sensing electrode 704 is located. The rear guard electrode may be arranged as a layer. The shape of the rear guard electrode may substantially correspond to the isolation element 730, or may be arranged to correspond to the shape (e.g., outer perimeter) of the distance sensor 701 (or the sensing electrode 704 and / or the guard electrode 703 of one distance sensor 701). The rear guard electrode may be useful in preventing the operation of the capacitive sensor from being affected by the current behind the capacitive sensor and the sensor from improperly affecting the control of the beam. An example of a rear guard electrode is shown in FIG. 5 of US2011 / 0261344, which is incorporated herein at least by reference to the disclosure of the rear guard electrode.

[0137] Figure 8 and Fig. 9 A sensor substrate 700 having a single aperture 711 is shown. Such a sensor substrate 700 may be used for a single primary charged particle beam. Preferably, the sensor substrate 700 is suitable for use with multiple primary charged particle beams. Although in theory multiple primary charged particle beams may pass through a single aperture, for example Figure 8 and Fig. 9The aperture 711 shown is a slit or slit array, but other configurations are possible. For example, the aperture 711 can be configured as a slit or slit array rather than a through hole. Such a slit can allow multiple primary charged particle beams to pass through it to reach the sample 208. Alternatively, the sensor substrate 700 can define an array of apertures 711. Each aperture in the array can provide a path for at least one primary charged particle beam (or sub-beam) to a target location. Fig.10 As shown, each aperture 711 may correspond to a single primary charged particle beam and / or primary charged particle beam path 320. The sensor substrate 700 may include an array of signal detectors 710. For example, the sensor substrate 700 may include at least one signal detector 710 associated with each aperture 711. Desirably, at least one signal detector 710 is positioned around at least one aperture 711. Thus, each aperture 711 may have a single corresponding signal detector 710 surrounding it, such as Fig.10 (Note that for convenience, features associated with some but not all detectors 710 and apertures 711 are labeled with reference numerals.) The signal detectors 710 may be arranged in a two-dimensional array. The two-dimensional array may be as described above with respect to Figure 4 The hexagonal close-packed array described above may be arranged differently, for example, in a rectangular array. As described above, the signal detector 710 may be configured as a single portion (e.g., a single electrode). Alternatively, the signal detector 710 may include multiple portions arranged around a single aperture 711, for example, as described above with respect to Figure 5A and Figure 5B described.

[0138] like Fig.10 As shown, the electrodes of the signal distance sensor 701 can be connected to the circuit system layer 720 through vias 705 and 706, as described above. Specifically, at least one via 705 can be provided to connect the guard electrode 703 (if provided) to the circuit system layer. At least one via 706 can be provided to connect the sensing electrode 704 to the circuit system layer 720. At least one signal detector 710 can have corresponding detector circuit system 712, such as Fig.10 Detector circuitry 712 may be separated from circuitry in other portions of circuitry layer 720, such as Fig.10 As shown, however, this is not required and the circuitry of signal detector 710 may be integrated with other circuit components in circuitry layer 720. Signal detector 710 may be connected to circuitry layer 720 (or more specifically, to detector circuitry 712 if detector circuitry 712 is provided as a discrete portion of the circuitry) via via 707.

[0139] The sensor substrate 700 may be the same as the substrate 404 described above, but with the addition of the distance sensor 701 described herein. In this case, the signal detector 710 may correspond to the detector electrode 405, and may be provided in any suitable arrangement.

[0140] The above-described embodiments generally include four distance sensors 701 that are substantially equally spaced from one another and at approximately the same radial distance from the center of the sensor substrate 700. However, it is not necessary to provide four distance sensors 701 that are approximately at the same radial distance. Instead, at least one distance sensor 701 may be at a different radial distance from the center than at least one other distance sensor 701. The distance sensors 701 may all be disposed at different radial distances from the center of the sensor substrate 700.

[0141] Additional or alternative distance sensors may be provided. For example, additional distance sensors may be provided, which are preferably positioned radially outward of the above-mentioned distance sensors. For example, additional distance sensors may be provided, which are preferably positioned radially inward of the above-mentioned distance sensors. These additional distance sensors may or may not be integrated with the sensor substrate 700.

[0142] Although a sensor substrate 700 having four distance sensors 701 is described above, any suitable number of distance sensors 701 may be provided. In one arrangement, for example, there may be two groups of eight distance sensors 701, all of which are preferably close to the charged particle component, which is located radially inward of the distance sensor. The distance sensors of the first group may be positioned equidistant from each other, for example, to provide the corners of a rectangle or even a square. Each of the remaining four sensors of the second group may be placed between two sensors of the first group, for example directly between two sensors of the first group. The sensors of the second group may be positioned equidistantly between adjacent sensors of the first group. In another embodiment, for example, the sensor substrate 700 may be provided with only one, i.e., a single distance sensor. Therefore, the above figure may be adjusted to have only one distance sensor. Although the sensor substrate 700 may still work using a single distance sensor 700, it is preferred to have multiple distance sensors to improve the accuracy of measuring the distance to the target and to align the surface of the sensor substrate relative to the target. For example, it is beneficial to include at least 3 distance sensors because these sensors can be used to ensure the alignment of the sensor substrate 700 relative to the target. For example, having four (4) distance sensors may be beneficial as it ensures that the sample is facing at least one distance sensor during operation of the charged particle device 41. Furthermore, the use of multiple distance sensors provides additional information relating to the distance to the target and may be used for more precise positioning, such as tilting, or rotating about an axis in a plane orthogonal to the beam path direction; i.e., two additional degrees of freedom. More than four distance sensors may also be provided. For example, any number of distance sensors between 5 and 20 or more may be provided, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more distance sensors may be provided as required. It should be noted that the distance sensor may be a differential sensor. Each distance sensor of the differential sensor may be considered to be a separate, distinct distance sensor, which is a separate capacitive sensor; alternatively, the distance sensor may comprise a differential sensor comprising two identical capacitive sensors.

[0143] Although the distance sensor 701 is described above as a capacitive sensor, at least one distance sensor 701 may additionally or alternatively be any suitable type of sensor. For example, the distance sensor 701 may be an inductive sensor. An inductive sensor may use an electromagnetic field to generate a measurement signal representing the distance between the inductive sensor and a target. The inductive sensor may include one or more current loops (or coils), for example within a substrate, which are excited by an AC current. The voltage on the current loop is proportional to the inductance of the loop. The inductance is affected by a magnet (such as a ferromagnetic material) within or near the loop. By moving the magnet relative to the ring, the inductance can change. For example, by moving the ferromagnetic material away from the ring, the inductance will become smaller. By doing this, the distance can be derived; for example, at least the change in the detected voltage signal can be used to derive the change in distance.

[0144] Although the signal detector 710 is described above as a charge-type detector, at least one signal detector 710 may additionally or alternatively be any suitable type of detector. For example, the signal detector 710 may include a semiconductor-type detector element, such as a PIN detector element, and / or a scintillation-type detector element.

[0145] The signal detector 710 described above is a charged particle optical component, which may be part of the sensor substrate 700. However, instead of or in addition to the signal detector 710, a different type of charged particle optical component may be provided.

[0146] It is described above that the detection surface 722 can be the main surface of the signal detector. If different types of charged particle optical components are provided, the main surface of the charged particle component can be any suitable surface for the specific function of the charged particle optical component. The main surface does not have to be the largest surface of the charged particle optical component, although it can be.

[0147] For example, the charged particle optical component may additionally or alternatively include a lens electrode configured to lens (i.e., converge or diverge) at least one charged particle beam. The charged particle optical component may include a macro electrostatic lens, which may desirably be disposed around an aperture as part of a single beam system, or may be disposed around multiple apertures for a multi-beam system. In this case, the substrate 700 may not be provided with an isolation element 730 (e.g., with Fig. 9Compared to), and a potential can be applied to the substrate 700 to serve as an electrode. For example, the charged particle optical component can be a part of an objective lens (or an objective lens array 241 as described above). In this case, the charged particle optical component can provide the most downstream electrode of the objective lens (or objective lens array 241). The distance measured by the distance sensor can be the distance between the sensor substrate and the sample 208 (indicating the distance between the lens and the sample). Alternatively, the charged particle component can be a part of a control lens (or a control lens array 250). In this case, the charged particle optical component can provide the most downstream electrode of the control lens (or control lens array 250). The distance measured by the distance sensor can be the distance between the sensor substrate and a downstream component as a target (indicating the distance between the lens and the target).

[0148] Additionally or alternatively, the charged particle optical component can include a lens plate when being a part of a multi-beam system. It is expected that the lens plate defines an aperture array, wherein each aperture can be aligned along one of the charged particle beam paths. Such a lens plate can be made of the silicon of a CMOS device. Desirably, the detector array is located upstream of the most downstream electrode arranged by the object lens (which can include the object lens and is expected to be the control lens electrode). The signal detector 710 can be positioned upstream of the detector substrate 700, for example, on a member arranged by the object lens or integrated into a member arranged by the object lens, or even upstream of the object lens arrangement.

[0149] Additionally or alternatively, the charged particle optical component may include a deflector electrode configured to deflect at least one charged particle beam. The charged particle optical component may include a plurality of deflector electrodes, wherein at least one deflector electrode is provided for each aperture. It is desirable that electrodes of different apertures are individually controllable. There may be a plurality of deflector electrodes for each at least one charged particle beam, so that the charged particle optical component may be provided as a multipole deflector or a multipole deflector array. An example of a multipole is described in US2012 / 0305798, for example at least with Figure 2 Related to Figure 6, which is incorporated herein by reference. It is desirable that multiple electrodes are arranged around each at least one aperture defined in the sensor substrate 700. In other words, there may be multiple electrodes associated with a single charged particle beam passing through the aperture. The multiple electrodes of each at least one aperture may be individually controllable. In one arrangement, the signal detector 710 or even the sensor array 241 is located downstream of the sensor substrate 700, and the sensor substrate 700 desirably includes one or more distance sensors 701 and multiple electrodes surrounding the apertures for one or more beam paths; in this arrangement, the sensor substrate may be farther from the sample location than the signal detector 710.

[0150] Although a substrate having at least one charged particle optical component is described above, the sensor substrate may be provided with a plurality of distance sensors without being provided with a charged particle optical component, i.e. without being provided with a Figures 8 to 10 Even if no charged particle component is provided, there is still the advantage that a plurality of distance sensors are directly aligned with each other and no calibration is required, for example, during operation. In particular, the sensor substrate 700 is desirably suitable for use in a multi-beam charged particle evaluation device. Desirably, the sensor substrate 700 includes the sensor substrate 700 as described above with respect to Fig.10 The multiple apertures 711. Fig.11 An example of such an embodiment is shown in , which includes a sensor substrate 700 having a distance sensor 701 as described above, but without any signal detector. It should be understood that any modifications and changes described herein with respect to the above-described sensor substrate 700 and / or distance sensor can be applied to such an embodiment without a signal detector 710 / charged particle optical component.

[0151] In the above figure, the sensor substrate 700 is shown as a square with a square distance sensor 701 and a circular charged particle component (signal detector 710). The sensor substrate 700, (multiple) distance sensors 701 and / or charged particle optical components can be respectively arranged in any appropriate shape in any appropriate combination. For example, the sensor substrate, (multiple) distance sensors and / or charged particle optical components can be substantially the same shape, or they can all be different shapes. At least two of the sensor substrate, (multiple) distance sensors and / or charged particle optical components can be the same shape. Any suitable shape includes, but is not limited to, square, hexagon, rectangle, circle, ellipse, triangle, polygon, semicircle, etc.

[0152] In one embodiment, a charged particle device 41 is provided. The charged particle device 41 is preferably configured to project multiple beams of charged particles to a sample position. The charged particle device 41 includes a sensor substrate 700 in any of the above embodiments or variations. The charged particle device 41 may include multiple sensor substrates 700, which may be positioned at different positions of the device. In this case, the charged particle optical components may be provided in different forms. For example, the sensor substrate 700 may be provided with at least one signal detector 710 and may be desirably positioned near the sample 208. Another sensor substrate may be provided with at least one control lens electrode and may be desirably positioned upstream of another sensor substrate. Additionally, the charged particle device may also include multiple charged particle components located upstream of the sensor substrate 700, which are positioned toward the sample position along the paths of multiple charged particle beams of the multiple beams, and the multiple charged particle components are configured to operate on multiple beams of the multiple beams. The multiple charged particle components may be any type of charged particle components, for example, as described above.

[0153] In one embodiment, a charged particle evaluation device for evaluating a sample 208 is provided. The charged particle evaluation device is preferably configured to project a charged particle beam toward a sample position. The charged particle evaluation device includes a sensor substrate 700 in any of the above embodiments or variations. The charged particle evaluation device may include a plurality of sensor substrates 700, which may be positioned at different locations of the device. In this case, the charged particle optical components may be provided in different forms. For example, the sensor substrate 700 may be provided with at least one signal detector 710, and may preferably be positioned near the sample 208. Another sensor substrate may be provided with at least one control lens electrode, and may desirably be positioned upstream of the other sensor substrate.

[0154] The charged particle optical device and / or the charged particle evaluation apparatus may further include a sample support (e.g., a sample holder 207) configured to support the sample 208. As described above, the sample support may be supported by the actuation stage 209. Desirably, the facing surface of the target is a surface of the sample 208 and / or the sample support.

[0155] The charged particle evaluation apparatus may further include a sample controller (e.g., controller 50) configured to control the position of the sample 208 and / or the sample holder based on the measurement signal from the distance sensor 701. The sample controller may be in electrical communication with the circuit system associated with the distance sensor 701. The controller and / or the distance sensor circuit system may process the measurement signal to determine the distance from the distance sensor 701 to the sample and / or determine whether the distance from the distance sensor 701 to the sample needs to be changed. The controller 50 may control the actuator stage 209 or any suitable actuator mechanism to move the sample 208 according to the measurement signal. The controller 50 may cause the actuator stage 209 to move the sample 208 in an upstream or downstream direction according to the measurement signal so as to adjust the distance between the sample 208 and / or the sample holder and the sensor substrate 700. If the target is not the sample 208, for example, a component, feature or part of a device or apparatus, or a product or article that is not part of a device or apparatus, etc., a drive mechanism may be provided for any suitable holder, which is configured to move the target and / or the target holder according to the measurement signal.

[0156] The charged particle optical device and / or the charged particle evaluation apparatus may further include a sensor controller (e.g., controller 50) configured to control the position of the sensor substrate 700 based on a measurement signal from the distance sensor. The sensor controller may be in electrical communication with a circuit system associated with the distance sensor 701, or may be part of a circuit system associated with the distance sensor 701. The sensor controller and / or the circuit system may process the measurement signal to determine the distance from the distance sensor 701 to the sample and / or determine whether the distance from the distance sensor 701 to the sample needs to be changed. The controller 50 may control any appropriate actuation mechanism to move the sensor substrate 700 in accordance with the measurement signal. The sensor controller may cause the actuation mechanism to move the sensor substrate in an upstream and / or downstream direction in accordance with the measurement signal in order to adjust the distance between the target and the sensor substrate 700.

[0157] The position of the sample 208, the sample support, and / or the sensor substrate 700 may be controlled to maintain the distance between the sensor substrate 700 and the sample 208 and / or the sample support. Thus, the measurement signal may be used to determine if there has been any change in the distance between the sensor substrate 700 and the sample 208 and / or the sample support, and appropriate adjustments may be made to move the sensor substrate 700 and / or the sample support.

[0158] In a charged particle evaluation apparatus, the sensor substrate 700 can be positioned near the sample 208 and / or the sample support. In a charged particle evaluation apparatus, the sensor substrate 700 can be positioned facing the sample 208 and / or the sample support. This may be particularly useful in a multi-beam system, which may have a larger field of view (e.g., approximately 5 to 20 mm per device), with preferred tight focusing (e.g., approximately 10 to 500 nanometers) and tilt requirements because the beams are not actively focused or have limited independent focusing. The distance between the device 41 and the sample may be small (e.g., approximately up to 250 microns, such as 30 to 100 microns), and the sample height may vary by up to approximately 50 microns, such as 30 microns. Therefore, accurately positioning the sensor substrate 700 relative to the sample 208 may be particularly beneficial given the morphological variations of the sample 208.

[0159] Desirably, the charged particle evaluation apparatus comprises the charged particle device in any one of the embodiments or variations described above, ie comprises a sensor substrate. Desirably, the charged particle evaluation apparatus comprises a source configured to emit a charged particle beam.

[0160] The present invention may also provide a method of generating a measurement signal representing the distance between a distance sensor 701 and a facing surface of a target using a sensor substrate 700 or a charged particle evaluation device as in any of the above variations or embodiments.

[0161] The present invention provides a method for generating a measurement signal representing the distance between a distance sensor 701 and a facing surface of a target using a sensor substrate 700, the sensor substrate 700 comprising at least one distance sensor 701 and at least one charged particle optical component, the method comprising a); positioning the sensor substrate 700 so that the distance sensor 701 faces the facing surface of the target; b) generating a measurement signal representing the distance between the distance sensor 701 and the facing surface of the target using the distance sensor 701. The method may include providing a sensor substrate 700 comprising at least one distance sensor 701 and at least one charged particle optical component, which may include exchanging a module comprising at least the sensor substrate 700 within an apparatus or a charged particle device.

[0162] A method for using a sensor substrate 700 including a plurality of distance sensors 701 to generate a measurement signal representing the distance between the distance sensor 701 and a facing surface of a target is provided, the method comprising: a) positioning the sensor substrate 700 so that the distance sensor 701 faces the facing surface of the target; b) using the distance sensor 701 to generate a measurement signal representing the distance between the distance sensor 701 and the facing surface of the target.

[0163] These methods can also include positioning the sample 208 and / or the sample holder and / or the sensor substrate 700 based on the measurement signal from the distance sensor 701. Desirably, positioning includes using a controller to control positioning. Positioning can include scanning the position of the sample 208 and / or the sample holder and / or the sensor substrate 700 relative to the primary charged particle beam directed at the sample 208.

[0164] The methods may further include detecting the signal particles. For example, the at least one charged particle optical component may be at least one signal detector 710 , wherein detecting the signal particles includes using the at least one signal detector 710 .

[0165] The present invention provides a method for projecting a charged particle beam onto a sample 208 so as to detect signal particles emitted from the sample 208 using a sensor substrate 700 including at least one distance sensor 701 and at least one signal detector 710, the method comprising a) positioning the sensor substrate 700 so that the distance sensor 701 faces a facing surface of the sample; b) using the distance sensor 701 to generate a measurement signal representing the distance between the distance sensor 701 and the facing surface of the sample 208; c) controlling the position of the sensor substrate 700 and / or the sample 208 and / or the sample holder based on the measurement signal; d) projecting the charged particle beam onto the surface of the sample 208 along the primary beam path 320; and e) detecting the signal particles emitted from the sample 208 at the at least one signal detector 710. Desirably, the beam used for the method is a multi-beam that strikes the sample 208. Therefore, the multi-beam may include a plurality of sub-beams. Desirably, the detection of the signal particles includes detecting the signal particles resulting from the impact of different sub-beams on the sample 208 using the plurality of signal detectors 710. For example, each signal detector 710 may be used to detect signal particles primarily or entirely from a single beamlet.

[0166] The sample controller and / or sensor controller can be part of a larger controller. For example, the sample controller and / or sensor controller can be connected to the controller 50 or communicate signals with the controller 50. Therefore, the sample controller and / or sensor controller can be part of a general controller (such as the controller 50), and does not have to be a controller specifically assigned to the sample or sensor substrate. The sample controller and / or sensor controller can have components for signal communication therewith, which are located outside the sample or sensor substrate 700 or the device 41 or the apparatus. Signal communication can be performed wirelessly or by wired (i.e., cable) connection. Therefore, for example, only a part of the sensor controller may be included in the sensor substrate 700. The sensor controller and / or sample controller may have a sub-controller. The sample controller and / or sensor controller may be provided separately from the controller 50.

[0167] In this specification, it should be understood that charged particles / signal particles are generally intended to be electrons or other negatively charged particles. However, in contrast to the above, charged particles / signal particles can be positively charged particles, such as ions. Therefore, a primary ion beam can be provided. Using a primary ion beam, secondary ions can be emitted from a sample, which can be detected by a charge-based detector. However, this will also produce negatively charged particles, such as secondary electrons, at the same time. Therefore, the charge accumulated using this charge-based detector will be a mixture of positively and negatively charged particles, which will make charged measurements unreliable. However, having a positive bias or negative bias on a charge-based detector will enable the selection of one of the charge polarities. Since the range of ions in the material is much smaller than that of electrons, backscattered ions require greater kinetic energy to reach any further detectors, such as scintillators and / or semiconductor-type detectors. Therefore, not all backscattered charged particles (or ions) can reach the detector element. In order to improve the detection of backscattered ions, the charge-based detector can be made thinner. In the case where ions are used instead of negatively charged particles, any bias described above would be reversed, e.g. a positive bias should be used instead of a negative bias, and vice versa.

[0168] The terms "sub-beam" and "beamlet" are used interchangeably herein and are both to be understood to include any radiation beam derived from a parent radiation beam by dividing or splitting the parent radiation beam. The term "manipulator" is used to include any element that affects a sub-beam or beamlet path, such as a lens or deflector. References to elements aligned along a beam path or beamlet path are to be understood as positioning the corresponding element along the beam path or beamlet path. References to optics are to be understood as electron optics.

[0169] Although the description and drawings are directed to electron optical systems, it should be understood that the embodiments are not intended to limit the present disclosure to specific charged particles. Therefore, references to electrons in this document may be considered more generally as references to charged particles, where the charged particles are not necessarily electrons. Charged particle optical devices can be configured to direct negatively charged particles to a sample location. Charged particle optical devices may also be referred to as electron optical devices. It should be understood that electrons are specific charged particles and that all charged particle instances mentioned throughout the application may be replaced as desired. For example, a source may specifically provide electrons. Charged particles mentioned throughout the specification may specifically be negatively charged particles.

[0170] The charged particle optical device or evaluation device can be more specifically defined as a charged particle optical device array. In other words, the device or apparatus can be provided as a device array. The device array can include a sensor substrate and an optional objective lens array and / or a focusing lens array.

[0171] The charged particle evaluation device may include an objective lens array 240. The charged particle evaluation device may include a detector array 241 and / or a detector assembly. The charged particle evaluation device may include a control lens array 250. Therefore, a charged particle evaluation device including an objective lens array and a detector array may be interchangeable with an objective lens array assembly and referred to as an objective lens array assembly, which may optionally include a control lens array 250. The charged particle evaluation device may include additional components, such as Figure 3 Thus, if the charged particle evaluation apparatus includes the additional components in these figures, the charged particle evaluation apparatus may be interchangeable with the charged particle evaluation tool 40 and / or the charged particle optical system and referred to as the charged particle evaluation tool 40 and / or the charged particle optical system. The charged particle evaluation apparatus may be referred to as a charged particle optical device, or at least include a charged particle optical device.

[0172] The evaluation tool according to one embodiment of the present invention can be a tool for qualitatively evaluating a sample (e.g., pass / fail), a tool for quantitatively measuring a sample (e.g., the size of a feature), or a tool for generating a sample image or map. Therefore, the evaluation tool can be any suitable equipment, device, or system for evaluation. For example, when used for evaluation, the evaluation tool can be any one of the charged particle optical devices, such as a part of the charged particle beam device 100, or more specifically a charged particle optical device 41, and / or as a part of an optical lens array assembly. Examples of evaluation tools are inspection tools (e.g., for identifying defects), review tools (e.g., for classifying defects), and measurement tools, or tools (e.g., measurement inspection tools) that can perform any combination of evaluation functions associated with inspection tools, review tools, or measurement tools. The charged particle beam tool 40 (which can be a charged particle optical device column) can be a part of an evaluation tool; such as an inspection tool or a measurement inspection tool, or a part of an electron beam lithography tool. Any reference herein to a tool is intended to encompass an apparatus, device or system, the tool comprising various components, which may or may not be co-located, even in separate rooms, particularly for example data processing elements.

[0173] References to up and down, upper and lower, lowest, upward and downward, above and below should be understood to refer to directions parallel to the upstream and downstream directions (typically but not always perpendicular) of the electron beam or beams impinging on the sample 208. Thus, references to upstream and downstream are intended to refer to the direction of the beam path independent of any existing gravitational field.

[0174] Reference to an element being aligned along a beam path or a sub-beam path is to be understood as referring to the respective element being positioned along the beam path or a sub-beam path.

[0175] Reference to a component or component system (such as a charged particle component) or element that can be controlled to manipulate a charged particle beam in a certain manner includes configuring a controller or control system or control unit to control the component to manipulate the charged particle beam in the described manner, and optionally using other controllers or devices (e.g., voltage sources and / or current sources) to control the component to manipulate the charged particle beam in this manner. For example, a voltage source can be electrically connected to one or more components to apply a potential to the component under the control of a controller or control system or control unit, such as including control lens array 250, objective lens array 241, convergence lens 231, corrector, collimator element array 271 and scanning deflector array 260 in a non-limiting list. Using one or more controllers, control systems or control units to control the actuation of the component, an actuable component (such as a stage) can be controllable to actuate and thus move relative to another component (such as a beam path).

[0176] Embodiments described herein including detector assemblies may take the form of a series of aperture arrays or charged particle optical elements arranged in an array along a beam or multi-beam path. Such charged particle optical elements may be electrostatic. In one embodiment, all charged particle optical elements (e.g., the last charged particle optical element in a sub-beam path from a beam limiting aperture array to a sample before) may be electrostatic and / or may be in the form of an aperture array or plate array. In some arrangements, one or more charged particle optical elements are manufactured as a micro-electromechanical system (MEMS) (i.e., using MEMS manufacturing techniques).

[0177] At least Figure 3 The device 41 (and / or any system or device including the device 41) of such an architecture as shown and described above may include components such as an upper beam limiter, a collimator element array 271, a control lens array 250, a scanning deflector array 260, an objective lens array 241, a beam shaping limiter and / or a detector array 241 and / or a detector assembly; one or more of these elements present may be connected to one or more adjacent elements via an isolation element such as a ceramic or glass spacer.

[0178] Any element or collection of elements within the charged particle beam tool 40 may be replaceable or field replaceable. One or more charged particle optical components in the charged particle beam tool 40, particularly those that manipulate or generate beamlets, such as aperture arrays and manipulator arrays, may include one or more MEMS.

[0179] Although the present invention has been described in conjunction with various embodiments, other embodiments of the present invention will be apparent to those skilled in the art from the specification disclosed herein and the practice of the present invention. The specification and examples should be considered as exemplary only, and the true scope and spirit of the present invention are indicated by the following claims and clauses.

[0180] The following terms are provided:

[0181] Item 1. A sensor substrate for a charged particle optical device and / or a charged particle evaluation apparatus, the sensor substrate comprising: at least one distance sensor configured to generate a measurement signal representing the distance between the distance sensor and a facing surface of a target; and at least one charged particle optical element.

[0182] Clause 2. The sensor substrate according to clause 1, comprising a plurality of distance sensors,

[0183] Clause 3. A sensor substrate for a multi-beam charged particle optical device and / or a charged particle evaluation apparatus, the sensor substrate comprising a plurality of distance sensors configured to generate a measurement signal representative of the distance between the distance sensors and a facing surface of a target.

[0184] Clause 4. The sensor substrate of Clause 3, further comprising at least one charged particle optical component.

[0185] Clause 5. A sensor substrate according to any one of clauses 2 to 4, wherein the substrate comprises at least 3 distance sensors, desirably at least 4 distance sensors, desirably more than 4 distance sensors.

[0186] Clause 6. A sensor substrate according to any one of clauses 2, 4 or 5, wherein the plurality of distance sensors are positioned around the at least one charged particle optical component, desirably wherein the plurality of distance sensors are positioned equidistant from an origin and / or adjacent distance sensors are separated by similar distances.

[0187] Clause 7. The sensor substrate of any preceding clause, wherein the distance sensor is adjacent to the at least one charged particle optical component.

[0188] Item 8. A sensor substrate according to any of the preceding items, wherein a sensing surface (e.g., a main surface) of the distance sensor and a main surface of the charged particle optical component are configured to face a target during operation, and desirably, the main surface of the charged particle optical component is a base of the charged particle optical device.

[0189] Clause 9. The sensor substrate of Clause 8, wherein the sensing surface of the distance sensor and the main surface of the charged-particle optical component are parallel to each other.

[0190] Clause 10. The sensor substrate of any of Clauses 8 or 9, wherein the sensing surface of the distance sensor and the main surface of the charged-particle optical component lie in the same plane.

[0191] Clause 11. The sensor substrate of any of the preceding clauses, wherein the sensing surface of the distance sensor lies in a main plane of the sensor substrate.

[0192] Clause 12. A sensor substrate as claimed in any preceding clause, wherein the distance sensor comprises at least a portion of an isolation element, desirably the or each distance sensor comprises a sensing electrode, desirably the sensing electrode being configured to be supported by the isolation element.

[0193] Item 13. A sensor substrate according to Item 12, wherein at least a portion of the circuit system of the sensor substrate is positioned in the isolation element, desirably, the circuit system in the portion of the isolation layer associated with at least one distance sensor is the circuit system of the at least one distance sensor, desirably, the shape of each portion corresponds to the shape of the distance sensor.

[0194] Clause 14. A sensor substrate according to any of the preceding clauses, wherein the charged particle optical component includes at least a portion of an isolation element, preferably, the charged particle element or each charged particle element includes one or more detector electrodes, preferably, the detector electrode or each detector electrode is configured to face the target during operation, and preferably, the optical electrode or each optical electrode is configured to be supported by the isolation element.

[0195] Item 15. A sensor substrate according to Item 14, wherein at least a portion of the circuit system of the sensor substrate is positioned in the isolation element, desirably, the circuit system in the portion of the isolation layer associated with the at least one charged particle optical component is the circuit system of the at least one charged particle optical component, desirably, the shape of each portion corresponds to the shape of the charged particle optical component.

[0196] Item 16. The sensor substrate according to any of the preceding items further includes a circuit system layer, wherein the circuit system layer includes a circuit system electrically connected to the distance sensor and / or the charged particle optical component through an isolation element, and desirably, the circuit system in the portion of the circuit system layer associated with the at least one distance sensor and / or the charged particle element is the circuit system of the distance sensor and / or the charged particle optical component, and desirably, the shape of each portion corresponds to the shape of the connected distance sensor and / or the charged particle optical component.

[0197] Clause 17. The sensor substrate of any of the preceding clauses, wherein the distance sensor is a capacitive sensor.

[0198] Clause 18. The sensor substrate of Clause 17, wherein the capacitive sensor comprises a sensing electrode and desirably comprises a guard electrode, desirably wherein the guard electrode surrounds the sensing electrode.

[0199] Clause 19. The sensor substrate of any one of Clauses 1 to 16, wherein the distance sensor is an inductive sensor.

[0200] Clause 20. A sensor substrate according to any preceding clause, wherein the distance sensors are differential sensors, desirably each distance sensor comprising two sensor elements, desirably the two sensor elements being configured to perform differential measurements with respect to each other.

[0201] Clause 21. The sensor substrate of any of the preceding clauses, wherein the charged particle optical component comprises a signal detector configured, in operation, to detect signal particles emitted from a sample.

[0202] Clause 22. The sensor substrate of Clause 15, wherein the signal detector comprises a charge-type detector element and / or a semiconductor-type detector element and / or a scintillation-type detector element.

[0203] Clause 23. The sensor substrate of any one of Clauses 21 or 22, further comprising circuitry configured to process a detection signal generated by the signal detector, desirably, the circuitry being included in the circuitry layer and / or the insulating layer.

[0204] Clause 24. The sensor substrate of any of the preceding clauses, further comprising circuitry configured to process the measurement signal from the distance sensor.

[0205] Clause 25. The sensor substrate of any of the preceding clauses, wherein at least one aperture is defined through the sensor substrate for passing at least one beam towards the sample.

[0206] Clause 26. The sensor substrate of Clause 25, wherein the sensor substrate defines an array of apertures for a path of at least one beam toward the sample location.

[0207] Item 27. A sensor substrate according to Item 26, wherein the sensor substrate comprises an array of corresponding charged particle optical components, wherein, desirably, at least one charged particle optical component is associated with at least one of the apertures, and wherein, desirably, at least one charged particle optical component is positioned around at least one of the apertures.

[0208] Clause 28. A sensor substrate according to any of the preceding clauses, wherein the sensor substrate comprises an array of charged particle optical components, desirably arranged in a two-dimensional array.

[0209] Clause 29. The sensor substrate of any of the preceding clauses, wherein the charged-particle optical component comprises a lens electrode configured to converge or diverge at least one charged-particle beam.

[0210] Clause 30. A sensor substrate according to any of the preceding clauses, wherein the charged particle optical component includes a deflector electrode configured to deflect at least one charged particle beam, desirably having a plurality of deflector electrodes for each at least one charged particle beam, desirably the plurality of electrodes are arranged around each at least one aperture defined in the sensor substrate, desirably wherein the electrodes for different apertures are capable of being individually controllable, desirably the plurality of electrodes for each at least one aperture are individually controllable.

[0211] Clause 31. A charged particle device for projecting a multi-beam charged particle towards a sample location, the charged particle device comprising a sensor substrate as described in any of the preceding clauses.

[0212] Item 32. The charged particle device according to Item 31 further includes a plurality of charged particle components located upstream of the sensor substrate, the plurality of charged particle components being positioned along paths of the plurality of charged particle beams of the multi-beam toward the sample position, the plurality of charged particle components being configured to operate on the plurality of beams of the multi-beam.

[0213] Item 33. A charged particle evaluation device for evaluating a sample, expected to be configured to project a charged particle beam toward the sample, the charged particle evaluation device comprising a sensor substrate as described in any of the preceding items, expected to include a source configured to emit a charged particle beam, and expected to include a charged particle device as described in item 31 or 32, wherein the charged particle device includes the sensor substrate.

[0214] Clause 34. A charged particle evaluation device for evaluating a sample, the charged particle evaluation device comprising a sensor substrate as described in any one of clauses 1 to 30.

[0215] Clause 35. A charged particle evaluation apparatus according to clause 33 or 34, further comprising a sample support configured to support the sample, desirably, wherein the facing surface of the target is a surface of the sample and / or the sample support.

[0216] Clause 36. The charged particle evaluation apparatus of Clause 35, further comprising a sample controller configured to control the position of the sample and / or sample holder based on a measurement signal from the distance sensor.

[0217] Clause 37. The charged particle assessment apparatus of any one of clauses 33 to 36, further comprising a sensor controller configured to control a position of the sensor substrate based on the measurement signal from the distance sensor.

[0218] Clause 38. A charged particle assessment apparatus according to any one of clauses 33 to 37, wherein the sensor substrate is positioned a) close to the sample and / or the sample support, and / or b) facing the sample and / or the sample support.

[0219] Item 39. A method for generating a measurement signal representing the distance between the distance sensor and a facing surface of a target using a sensor substrate comprising at least one distance sensor and at least one charged particle optical component, the method comprising: a) positioning the sensor substrate so that the distance sensor faces the facing surface of the target; and b) using the distance sensor to generate a measurement signal representing the distance between the distance sensor and the facing surface of the target.

[0220] Item 40. A method for generating a measurement signal representing the distance between the distance sensor and a facing surface of a target using a sensor substrate including a plurality of distance sensors, the method comprising: a) positioning the sensor substrate so that the distance sensor faces the facing surface of the target; and b) using the distance sensor to generate a measurement signal representing the distance between the distance sensor and the facing surface of the target.

[0221] Clause 41. The method according to any one of clauses 39 or 40, further comprising positioning the sample and / or sample holder and / or the sensor substrate based on the measurement signal from the distance sensor, the positioning desirably comprising controlling the positioning using a controller.

[0222] Clause 42. A method according to clause 41, wherein the positioning comprises scanning the position of the sample and / or the sample holder and / or the sensor substrate relative to the primary charged particle beam directed at the sample

[0223] Clause 43. The method of any one of clauses 39 to 42, further comprising detecting signal particles.

[0224] Clause 44. The method of clause 43, wherein the at least one charged-particle optical component is at least one signal detector, and detecting signal particles comprises using the at least one signal detector.

[0225] Item 45. A method for projecting a charged particle beam onto a sample so as to detect signal particles emitted from the sample using a sensor substrate comprising at least one distance sensor and at least one signal detector, the method comprising: a) positioning the sensor substrate so that the distance sensor faces a facing surface of the sample; b) using the distance sensor to generate a measurement signal representing the distance between the distance sensor and the facing surface of the sample; c) controlling the position of the sensor substrate and / or the sample and / or the sample holder based on the measurement signal; d) projecting the charged particle beam onto the surface of the sample along a primary beam path; and e) detecting the signal particles emitted from the sample at the at least one signal detector.

[0226] Item 46. A method according to Item 45, wherein the beam is a multi-beam when striking the sample, the multi-beam comprising a plurality of sub-beams, and desirably, the detection of signal particles comprises using a plurality of signal detectors to detect signal particles obtained from different sub-beams striking the sample.

Claims

1. A sensor substrate for a charged particle optical device and / or a charged particle evaluation device, the sensor substrate comprising: at least one distance sensor configured to generate a measurement signal representative of a distance between the distance sensor and a facing surface of a target; as well as At least one charged particle optic.

2. The sensor substrate according to claim 1, comprising a plurality of distance sensors.

3. The sensor substrate of claim 2, wherein the plurality of distance sensors are positioned around the at least one charged particle optical component. 4 . The sensor substrate of claim 3 , wherein the plurality of distance sensors are located equidistantly from an origin and / or adjacent distance sensors are spaced by similar distances.

5. The sensor substrate according to any of the preceding claims, wherein the distance sensor is close to the at least one charged particle optical component.

6. The sensor substrate according to any of the preceding claims, wherein a sensing surface of the distance sensor and a main surface of the charged particle optical component are arranged to face a target in operation. 7 . The sensor substrate according to claim 6 , wherein the sensing surface of the distance sensor and the main surface of the charged particle optical component are parallel to each other.

8. The sensor substrate according to claim 6 or 7, wherein the sensing surface of the distance sensor is in the same plane as the main surface of the charged particle optical component.

9. A sensor substrate according to any preceding claim, wherein the distance sensor comprises at least a portion of an isolation element, desirably the or each distance sensor comprises a sensing electrode, desirably the sensing electrode being arranged to be supported by the isolation element.

10. The sensor substrate of claim 9, wherein at least a portion of circuitry of the sensor substrate is positioned in the isolation element.

11. The sensor substrate of claim 10, wherein the circuitry in a portion of the isolation layer associated with the at least one distance sensor is the circuitry of the at least one distance sensor, desirably each portion corresponding in shape to a shape of the distance sensor.

12. The sensor substrate according to any of the preceding claims, wherein the distance sensor is a capacitive sensor.

13. The sensor substrate according to any of the preceding claims, wherein the charged particle optical component comprises a signal detector configured to detect signal particles emitted from the sample when in operation.

14. A sensor substrate according to any of the preceding claims, wherein the charged particle optical component comprises at least a portion of an isolation element, desirably, the charged particle element or each charged particle element comprises one or more detector electrodes, desirably, the detector electrode or each detector electrode is configured to face the target during operation.

15. The sensor substrate according to any of the preceding claims, wherein at least one aperture is defined through the sensor substrate for passing the at least one beam towards the sample.

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