Switching matrix configuration for improved bandwidth performance

Abstract

The charged particle detector includes a plurality of sensing elements. The sensing element may be divided into a plurality of portions, each portion including an array of sensing elements. Each portion may be coupled to an adjacent portion by a set of switches in a higher level of the switch matrix. Each sensing element may be connected to a higher level in a portion thereof through a pick-up switch. Each sensing element may also be coupled to an adjacent sensing element through a lateral switch in a lower level. When the sensing elements are combined together to detect a charged particle beam spot, the optimal configuration of the lower level and higher level switches can be selected to optimize the bandwidth performance of the detector.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to EP application 22189812.5 filed on August 11, 2022, and the entire contents of which are incorporated herein by reference. Technical Field

[0003] The description herein relates to detectors, and more particularly, to detectors suitable for charged particle detection. Background Art

[0004] Detectors can be used to sense physically observable phenomena. For example, some charged particle beam tools (e.g., electron microscopes) include detectors that receive charged particles projected from a sample and output a detection signal. The detection signal can be used to reconstruct an image of the structure of the sample being inspected, and can be used, for example, to reveal defects in the sample. In the manufacture of semiconductor devices, it is increasingly important to detect defects in samples, which may include a large number of densely packed miniature integrated circuit (IC) components. Inspection systems can be provided for this purpose. For example, charged particle (e.g., electron) beam microscopes (e.g., scanning electron microscopes (SEMs) or transmission electron microscopes (TEMs)) are able to reduce resolution to less than 1 nanometer and can be used as practical tools for inspecting IC components with feature sizes less than 100 nanometers. The working principle of an electron microscope is to irradiate a sample with an electron beam and then detect secondary or backscattered electrons (or other types of secondary particles) on a detector. Secondary particles may form one or more beam spots on the surface of the detector.

[0005] Some detectors include a pixelated array of multiple sensing elements. The pixelated array is useful because it allows the detector configuration to be adapted to the size and shape of the beam spot formed on the detector. When multiple primary beams are used, multiple secondary beam spots are incident on the detector, and the pixelated array of sensing elements can be divided into different groups associated with different beam spots. Sensing elements within a single group can combine their detection signals with each other for readout by the processing circuitry of the detector. The network of electronic switches used to group the sensing elements together and combine their detection signals can be referred to as a "switch matrix". Summary of the invention

[0006] Some embodiments of the present disclosure provide a method for configuring a switch matrix in a charged particle detector. The method may include: disabling a first inter-element switch between a first sensing element and a second sensing element of the charged particle detector to prevent charge from flowing between the first sensing element and the second sensing element through the first inter-element switch, the first inter-element switch forming part of a lower level of the switch matrix; enabling a first pick-up switch between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level through the first pick-up switch; and enabling a second pick-up switch between the second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level through the second pick-up switch. The first sensing element and the second sensing element may be coupled to a common analog signal path of the higher level detector.

[0007] Certain embodiments of the present disclosure provide a non-transitory computer-readable medium storing an instruction set, which can be executed by at least one processor of a device to enable the device to perform the above method.

[0008] Some embodiments of the present disclosure provide a charged particle beam device configured to perform the above method. The charged particle beam device may include: a charged particle beam source configured to generate a primary charged particle beam; a charged particle optical system configured to guide the primary charged particle beam to a sample surface to inspect the sample surface; a charged particle detector configured to detect charged particles returned from the sample surface, wherein the charged particle detector includes a first sensing element and a second sensing element; and a controller including one or more processors and configured to cause the charged particle beam device to perform the above method.

[0009] Some embodiments of the present disclosure provide additional methods for configuring a switch matrix in a charged particle detector. Additional methods may include: enabling a first pick-up switch between a first sensing element and a first node of a higher level of the switch matrix to allow charge to flow between the first sensing element and the first node via the first pick-up switch, the first sensing element receiving the charged particles of the first beam spot; enabling a first inter-element switch between a second sensing element and a third sensing element to allow charge to flow between the second sensing element and the third sensing element via the first inter-element switch, the second sensing element and the third sensing element receiving the charged particles of the second beam spot; disabling a second pick-up switch between the second sensing element and the first node to prevent charge from flowing between the second sensing element and the first node via the pick-up switch; and enabling a third pick-up switch between the second sensing element and a third node of a higher level of the switch matrix to allow charge to flow between the third sensing element and the second node via the third pick-up switch.

[0010] Certain embodiments of the present disclosure provide a non-transitory computer-readable medium storing an instruction set that can be executed by at least one processor of a device to cause the device to perform the above-mentioned additional method.

[0011] Some embodiments of the present disclosure provide a charged particle beam device configured to perform the above method. The charged particle beam device may include: a charged particle beam source configured to generate a primary charged particle beam; a charged particle optical system configured to guide the primary charged particle beam to a sample surface to inspect the sample surface; a charged particle detector configured to detect charged particles returned from the sample surface, wherein the charged particle detector includes a first sensing element and a second sensing element; and a controller including one or more processors and configured to cause the charged particle beam device to perform the above additional method.

[0012] Some embodiments of the present disclosure provide a charged particle detector having a switch matrix including a higher level and a lower level. The charged particle detector may include: a plurality of sections, each section including a plurality of sensing element circuits arranged in an array, each sensing element circuit including: a sensing element configured to generate a charge from a charged particle landing event at the sensing element; a pick-up switch configured to couple the sensing element to a higher level node of the switch matrix in the section; and an inter-element switch configured to couple the sensing element to an adjacent sensing element to allow charge to flow between the sensing element and the adjacent sensing element, the inter-element switch forming a part of the lower level. Within each of the plurality of sections, each sensing element may be configured to be coupled to a higher level common node in the section via its respective pick-up switch.

[0013] Some embodiments of the present disclosure provide a charged particle beam device. The charged particle beam device may include: a charged particle beam source configured to generate a primary charged particle beam; a charged particle optical system configured to guide the primary charged particle beam to a sample surface to inspect the sample surface; a charged particle detector configured to detect charged particles returned from the sample surface, wherein the charged particle detector includes a first sensing element and a second sensing element; a first inter-element switch configured to be disabled between the first sensing element and the second sensing element to prevent charge from flowing between the first sensing element and the second sensing element via the first inter-element switch, the first inter-element switch forming part of a lower level of a switch matrix; a first pick-up switch configured to be enabled between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level via the first pick-up switch; and a second pick-up switch configured to be disabled between the second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level via the second pick-up switch. The first sensing element and the second sensing element may be coupled to a common analog signal path of a higher level detector.

[0014] Some embodiments of the present disclosure provide a charged particle beam device. The charged particle beam device may include: a charged particle beam source configured to generate a primary charged particle beam; a charged particle optical system configured to guide the primary charged particle beam to a sample surface to inspect the sample surface; a charged particle detector configured to detect charged particles returned from the sample surface, wherein the charged particle detector includes a first sensing element, a second sensing element, and a third sensing element; a first pick-up switch configured to be enabled between the first sensing element and a first node of a higher level of a switch matrix to allow charge to flow between the first sensing element and the first node via the first pick-up switch, the first sensing element being configured to receive charged particles of a first beam spot; a second sensing element configured to detect charged particles of a first beam spot; and a third sensing element configured to detect charged particles of a first beam spot. an inter-element switch configured to be enabled between a second sensing element and a third sensing element to allow charge to flow between the second sensing element and the third sensing element via the first inter-element switch, the second sensing element and the third sensing element being configured to receive charged particles of a second beam spot; a second pick-up switch configured to be disabled between the second sensing element and the first node to prevent charge from flowing between the second sensing element and the first node via the pick-up switch; and a third pick-up switch configured to be enabled between the third sensing element and a second node of a higher level of the switch matrix to allow charge to flow between the third sensing element and the second node via the third pick-up switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram illustrating an exemplary charged particle beam inspection system consistent with embodiments of the present disclosure.

[0016] Figure 2 is a schematic diagram showing an exemplary multi-beam tool consistent with an embodiment of the present disclosure, which may be Figure 1 A portion of an exemplary charged particle beam inspection system.

[0017] Figure 3A is a schematic diagram of an exemplary structure of a detector consistent with an embodiment of the present disclosure.

[0018] Figure 3B is a diagram illustrating an exemplary surface of a detector array consistent with embodiments of the present disclosure.

[0019] Figure 4 is a diagram illustrating an exemplary detector array with switches consistent with embodiments of the present disclosure.

[0020] Figure 5 is a diagram showing a cross-sectional view of a layer structure of a detector consistent with an embodiment of the present disclosure.

[0021] Figure 6 is a diagram illustrating a cross-sectional view of a sensing element of a detector consistent with an embodiment of the present disclosure.

[0022] Figure 7 is a diagram showing an exemplary partial arrangement of a detector consistent with an embodiment of the present disclosure.

[0023] Figure 8 is a diagram illustrating a detection system consistent with an embodiment of the present disclosure.

[0024] Figure 9A-9C is a diagram showing a detection system and a switch matrix configuration according to a comparative embodiment.

[0025] Figure 10A-10C is a diagram illustrating a detector array having an exemplary architecture, consistent with an embodiment of the present disclosure.

[0026] Fig.11 is a diagram illustrating a beam spot on an exemplary detector surface consistent with an embodiment of the present disclosure.

[0027] Fig.12 is a flow chart of an exemplary method of implementing switch configuration consistent with embodiments of the present disclosure. DETAILED DESCRIPTION

[0028] 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 indicated, 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 disclosure. On the contrary, they are merely examples of devices and methods consistent with aspects related to the subject matter described in the appended claims. For example, although some embodiments are described in the context of utilizing charged particle beams (e.g., electron beams), the present disclosure is not limited thereto. Other types of charged particle beams may be applied similarly. In addition, other imaging systems, such as optical imaging, photoelectric detection, x-ray detection, etc., may be used.

[0029] Electronic devices are formed from circuits formed on a semiconductor material called a substrate. The semiconductor material may include, for example, silicon, gallium arsenide, indium phosphide, or silicon germanium. Many circuits can be formed together on the same silicon wafer, called an integrated circuit, or IC. The size of these circuits has been greatly reduced so that more circuits can fit on a substrate. For example, an IC chip in a smartphone can be as small as a thumbnail, but may contain more than 2 billion transistors, each less than one thousandth the size of a human hair.

[0030] Manufacturing these ICs, which have extremely small structures or components, is a complex, time-consuming, and expensive process that typically involves hundreds of individual steps. An error in even one step can cause a defect in the finished IC, rendering it unusable. Therefore, one goal of the manufacturing process is to avoid such defects in order to maximize the number of functional ICs manufactured in the process; that is, to increase the yield of the overall process.

[0031] An integral part of improving yield is monitoring the chip manufacturing process to ensure that sufficient numbers of functional integrated circuits are produced. One way to monitor the process is to inspect the chip circuit structures at various stages of their formation. Inspection can be performed using a scanning charged particle microscope ("SCPM"). For example, the SCPM can be a scanning electron microscope (SEM). The SCPM can be used to image these extremely small structures, in effect taking a "photograph" of the wafer structure. This image can be used to determine if the structure is formed correctly in the correct location. If the structure is defective, the process can be adjusted to reduce the likelihood that the defect will occur again.

[0032] The working principle of the SEM is similar to that of a camera. A camera takes a picture by receiving and recording the intensity of light reflected or emitted from a person or object. The SEM takes a picture by receiving and recording the energy or number of electrons reflected or emitted from a wafer structure. Before taking such a "picture", an electron beam can be projected onto the structure, and when the electrons are reflected or emitted ("leave") from the structure (e.g., from the wafer surface, from the structure below the wafer surface, or both), the detector of the SEM can receive and record the energy or number of these electrons to generate an inspection image. To take such a "picture", the electron beam can scan the wafer (e.g., in a row-by-row or zigzag manner), and the detector can receive the exiting electrons from the area under the projection of the electron beam (called a "beam spot"). The detector can receive and record the exiting electrons from each beam spot at a time, and merge the information recorded for all beam spots to generate an inspection image. Some SEMs use a single electron beam (called "single-beam SEM") to take a single "photo" to generate a detection image, while some SEMs use multiple electron beams (called "multi-beam SEM") to take multiple "sub-photos" of the wafer in parallel and stitch them together to generate a detection image. By using multiple electron beams, the SEM can provide more electron beams to the structure to obtain these multiple "sub-photos", resulting in more electrons being ejected from the structure. Therefore, the detector can receive more ejected electrons at the same time and generate a detection image of the wafer structure with higher efficiency and faster speed.

[0033] Since a detector may need to capture a large number of detection cycles in a short period of time, one of the key factors in the performance of a detector is its processing speed. One way to increase processing speed is to maximize the speed at which data can be transferred from the detector. This data transfer rate is called bandwidth. Bandwidth can vary depending on the number and size of circuit elements within the detector. Each element connected to a detector system adds unwanted electrical effects, called parasitics, which can slow down the system. Therefore, processing speed can be increased by minimizing the number of circuit elements electrically connected to the system at any given time.

[0034] In addition to minimizing the total number of circuit components, it is also beneficial to design the component structure in a way that reduces the impact of the component on parasitic parameters. For example, if the amount of current expected to pass through a circuit component can be reduced, the size of the component can be reduced to reduce its parasitic effects.

[0035] Speed ​​is not the only consideration for charged particle detectors. For some detectors, another important factor is adaptability. Since a single detector surface may detect multiple beam spots simultaneously, the detector must be able to separate the signal it receives from each beam spot. To do this, the detector can be pixelated, for example by dividing the sensing surface into a grid of smaller sensing elements, where each sensing element corresponds to a pixel on the detector surface. The detector pixels can be connected to each other through a network of electronic switches called a switch matrix. The switch matrix can link a first group of detection pixels to detect a first beam spot, and can link a second group of detection pixels to detect a second beam spot. The signals from the two groups can be routed to the processor along different signal paths to detect the beam spots separately. Unused detection pixels between two beam spots can be deactivated. While pixelated detectors are highly configurable, they also require a large number of switches and other electronic components in the switch matrix, which can compromise bandwidth and processing speed.

[0036] Some embodiments of the present disclosure provide a pixelated electronic detector architecture that achieves high configurability and high bandwidth by using a layered pixel switch array. Some embodiments of the layered pixel switch array may include an array of detection pixels that can be selectively interconnected through a switch matrix. The switch matrix may include a higher level layer with an upper switch, a lower level layer with a lower switch, and a pick-up switch located between the two levels. Each sensing element can be coupled to an adjacent sensing element using a lower level layer switch. Each sensing element can be coupled to a higher level layer through a dedicated pick-up switch. The higher level layer can be used to couple parts of the switch to each other. Due to the flexibility of the switch matrix, a group of detector pixels can be coupled to each other through many different switch combinations. The best switch combination can be selected to maximize bandwidth and processing speed. Any unnecessary switches can be disabled to reduce parasitic parameters.

[0037] For the sake of clarity, the relative sizes of the components in the figures may be exaggerated. In the following description of the figures, the same or similar reference numerals denote the same or similar components or entities, and only the differences with respect to the various embodiments are described.

[0038] The objects and advantages of the present invention can be achieved by the elements and combinations thereof described in the embodiments described herein. However, the embodiments of the present invention are not necessarily required to achieve these exemplary objects or advantages, and some embodiments may not achieve any of the objects or advantages.

[0039] Without limiting the scope of the present disclosure, some embodiments may be described in the context of providing detection systems and detection methods in systems utilizing electron beams ("e-beams"). However, the present disclosure is not limited thereto. Other types of charged particle beams may be similarly applied. In addition, the detection systems and methods may be used in other imaging systems, such as optical imaging, photon detection, x-ray detection, ion detection, and the like.

[0040] As used herein, unless expressly stated otherwise, the term "or" encompasses all possible combinations unless not feasible. For example, if a component is specified to include A or B, then unless expressly stated otherwise or not feasible, the component may include A, or B, or A and B. As a second example, if a component is specified to include A, B, or C, then unless expressly stated otherwise or not feasible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0041] Figure 1 An exemplary electron beam inspection (EBI) system 100 consistent with embodiments of the present disclosure is shown. The EBI system 100 may be used for imaging. Figure 1 As shown, the EBI system 100 includes a main chamber 101, a load / lock chamber 102, a beam tool 104, and an equipment front end module (EFEM) 106. The beam tool 104 is located in the main chamber 101. The EFEM 106 includes a first load port 106a and a second load port 106b. The EFEM 106 may include additional load ports. The first load port 106a and the second load port 106b receive a wafer front opening transport box (FOUP) containing a wafer (e.g., a semiconductor wafer or a wafer made of other materials) or a sample to be inspected (wafers and samples can be used interchangeably). "Batch" refers to a plurality of wafers that can be loaded and processed as a batch.

[0042] One or more robots (not shown) in the EFEM 106 can transport the wafer to the load / lock chamber 102. The load / lock chamber 102 is connected to a load / lock vacuum pump system (not shown), which removes gas molecules in the load / lock chamber 102 to reach a first pressure below atmospheric pressure. After reaching the first pressure, one or more robots (not shown) can transport the wafer from the load / lock chamber 102 to the main chamber 101. The main chamber 101 is connected to a main chamber vacuum pump system (not shown), which removes gas molecules in the main chamber 101 to reach a second pressure below the first pressure. After reaching the second pressure, the wafer will be inspected by the beam tool 104. The beam tool 104 can be a single beam system or a multi-beam system.

[0043] The controller 109 is electronically connected to the beam tool 104. The controller 109 may be a computer configured to perform various controls of the EBI system 100. Figure 1 The controller 109 is shown in FIG. 1 as being external to the structure including the main chamber 101 , the load / lock chamber 102 , and the EFEM 106 , but it will be appreciated that the controller 109 may be part of the structure.

[0044] In some embodiments, the controller 109 may include one or more processors (not shown). The processor may be a general or special electronic device capable of manipulating or processing information. For example, the processor may include any number of any combination of the following: a central processing unit (or "CPU"), a graphics processing unit (or "GPU"), an optical processor, a programmable logic controller, a microcontroller, a microprocessor, a digital signal processor, an intellectual property (IP) core, a programmable logic array (PLA), a programmable array logic (PAL), a general array logic (GAL), a complex programmable logic device (CPLD), a field programmable gate array (FPGA), a system on a chip (SoC), an application-specific integrated circuit (ASIC), and any type of circuit capable of data processing. The processor may also be a virtual processor, which includes one or more processors distributed on multiple machines or devices coupled via a network.

[0045] In some embodiments, the controller 109 may also include one or more memories (not shown). The memory may be a general or specific electronic device capable of storing processor-accessible code and data (e.g., via a bus). For example, the memory may include any number of any combination of the following: random access memory (RAM), read-only memory (ROM), optical disk, magnetic disk, hard disk, solid-state drive, flash drive, secure digital (SD) card, memory stick, compact flash (CF) card, or any type of storage device. The code and data may include an operating system (OS) and one or more applications (or "apps") for specific tasks. The memory may also be a virtual memory, which includes one or more memories distributed on multiple machines or devices coupled via a network.

[0046] Figure 2 An exemplary multi-beam tool 104 (also referred to herein as apparatus 104) and an ...) consistent with embodiments of the present disclosure and configurable for use with an EBI system 100 ( Figure 1 ) is a schematic diagram of an image processing system 290.

[0047] The beam tool 104 includes a charged particle source 202, a gun aperture 204, a converging lens 206, a primary charged particle beam 210 emitted from the charged particle source 202, a source conversion unit 212, a plurality of sub-beams 214, 216, and 218 of the primary charged particle beam 210, a primary projection optical system 220, a motorized wafer stage 280, a wafer holder 282, a plurality of secondary charged particle beams 236, 238, and 240, a secondary optical system 242, and a charged particle detection device 244. The primary projection optical system 220 may include a beam splitter 222, a deflection scanning unit 226, and an objective lens 228. The charged particle detection device 244 may include detection sub-areas 246, 248, and 250.

[0048] Charged particle source 202, gun aperture 204, focusing lens 206, source conversion unit 212, beam splitter 222, deflection scanning unit 226, and objective lens 228 may be aligned with a primary optical axis 260 of apparatus 104. Secondary optical system 242 and charged particle detection device 244 may be aligned with a secondary optical axis 252 of apparatus 104.

[0049] The charged particle source 202 may emit one or more charged particles, such as electrons, protons, ions, muons, or any other particles carrying an electric charge. In some embodiments, the charged particle source 202 may be an electron source. For example, the charged particle source 202 may include a cathode, an extractor, or an anode, wherein primary electrons may be emitted from the cathode and extracted or accelerated to form a primary charged particle beam 210 (in this case, a primary electron beam) having a crossover point (virtual or real) 208. For ease of explanation and without ambiguity, electrons are used as examples in some descriptions herein. However, it should be noted that any charged particles may be used in any embodiment of the present disclosure, not limited to electrons. The primary charged particle beam 210 may be considered to be emitted from the crossover point 208. The gun aperture 204 may block the peripheral charged particles of the primary charged particle beam 210 to reduce the Coulomb effect. The Coulomb effect may cause the detection point size to increase.

[0050] The source conversion unit 212 may include an image forming element array and a beam limiting aperture array. The image forming element array may include a micro deflector or a micro lens array. The image forming element array may form multiple parallel images (virtual or real) of the intersection 208 with the multiple sub-beams 214, 216, and 218 of the primary charged particle beam 210. The beam limiting aperture array may limit the multiple sub-beams 214, 216, and 218. Although Figure 2 , three sub-beams 214, 216, and 218 are shown, but embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the apparatus 104 may be configured to generate a first number of sub-beams. In some embodiments, the first number of sub-beams may be in the range of 1 to 1000. In some embodiments, the first number of sub-beams may be in the range of 200-500. In an exemplary embodiment, the apparatus 104 may generate 400 sub-beams.

[0051] The converging lens 206 can focus the primary charged particle beam 210. By adjusting the focusing ability of the converging lens 206 or changing the radial size of the corresponding beam-limiting aperture in the beam-limiting aperture array, the current of the sub-beams 214, 216 and 218 downstream of the source conversion unit 212 can be changed. The objective lens 228 can focus the sub-beams 214, 216 and 218 onto the wafer 230 for imaging, and can form a plurality of detection points 270, 272 and 274 on the surface of the wafer 230.

[0052] The beam splitter 222 can be a Wien filter type beam splitter that generates an electrostatic dipole field and a magnetic dipole field. In some embodiments, if they are applied, the force exerted by the electrostatic dipole field on the charged particles (e.g., electrons) of the sub-beams 214, 216, and 218 can be substantially equal in magnitude and opposite in direction to the force exerted by the magnetic dipole field on the charged particles. Therefore, the sub-beams 214, 216, and 218 can pass directly through the beam splitter 222 at a zero deflection angle. However, the total dispersion of the sub-beams 214, 216, and 218 generated by the beam splitter 222 can also be non-zero. The beam splitter 222 can separate the secondary charged particle beams 236, 238, and 240 from the sub-beams 214, 216, and 218, and direct the secondary charged particle beams 236, 238, and 240 to the secondary optical system 242.

[0053] The deflection scanning unit 226 can deflect the beamlets 214, 216, and 218 to scan the detection points 270, 272, and 274 on the surface area of ​​the wafer 230. In response to the incidence of the beamlets 214, 216, and 218 at the detection points 270, 272, and 274, secondary charged particle beams 236, 238, and 240 can be emitted from the wafer 230. The secondary charged particle beams 236, 238, and 240 may include charged particles (e.g., electrons) having an energy distribution. For example, the secondary charged particle beams 236, 238, and 240 may be secondary electron beams, including secondary electrons (energy ≤ 50 eV) and backscattered electrons (energy between 50 eV and the landing energy of the beamlets 214, 216, and 218). The secondary optical system 242 can focus the secondary charged particle beams 236, 238, and 240 onto detection sub-regions 246, 248, and 250 of the charged particle detection device 244. The detection sub-regions 246, 248, and 250 can be configured to detect the corresponding secondary charged particle beams 236, 238, and 240 and generate corresponding signals (e.g., voltage, current, etc.) for reconstructing the SCPM image of the structure on or below the surface area of ​​the wafer 230.

[0054] The generated signals may represent the intensities of the secondary charged particle beams 236, 238, and 240, and may be provided to an image processing system 290 in communication with the charged particle detection device 244, the primary projection optical system 220, and the motorized wafer stage 280. The movement speed of the motorized wafer stage 280 may be synchronized and coordinated with the beam deflection controlled by the deflection scanning unit 226, so that the movement of the scanning detection points (e.g., scanning detection points 270, 272, and 274) may orderly cover the region of interest on the wafer 230. The parameters of such synchronization and coordination may be adjusted to accommodate different materials of the wafer 230. For example, different materials of the wafer 230 may have different resistance-capacitance characteristics, which may result in different signal sensitivities to the movement of the scanning detection points.

[0055] The intensity of the secondary charged particle beams 236, 238, and 240 may vary depending on the external or internal structure of the wafer 230, and thus may indicate whether the wafer 230 contains defects. In addition, as described above, the sub-beams 214, 216, and 218 may be projected to different locations on the top surface of the wafer 230 or different sides of the local structure of the wafer 230 to generate secondary charged particle beams 236, 238, and 240 that may have different intensities. Therefore, by mapping the intensities of the secondary charged particle beams 236, 238, and 240 to the regions of the wafer 230, the image processing system 290 may reconstruct an image reflecting the internal or external structural features of the wafer 230.

[0056] In some embodiments, the image processing system 290 may include an image acquirer 292, a memory 294, and a controller 296. The image acquirer 292 may include one or more processors. For example, the image acquirer 292 may include a computer, a server, a mainframe, a terminal, a personal computer, any type of mobile computing device, etc., or a combination thereof. The image acquirer 292 may be communicatively coupled to the charged particle detection device 244 of the beam tool 104 through a medium such as an electrical conductor, a fiber optic cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, radio, or a combination thereof. In some embodiments, the image acquirer 292 may receive a signal from the charged particle detection device 244 and may construct an image. Thus, the image acquirer 292 may acquire an SCPM image of the wafer 230. The image acquirer 292 may also perform various post-processing functions, such as generating contours, superimposing indicators on the acquired image, etc. The image acquirer 292 may be configured to perform brightness and contrast adjustments of the acquired image. In some embodiments, the memory 294 may 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 294 may be coupled to the image acquirer 292 and may be used to save the scanned raw image data as raw images and post-processed images. The image acquirer 292 and the memory 294 may be connected to the controller 296. In some embodiments, the image acquirer 292, the memory 294 and the controller 296 may be integrated together as a control unit.

[0057] In some embodiments, the image acquirer 292 may acquire one or more SCPM images of the wafer based on the imaging signal received from the charged particle detection device 244. The imaging signal may correspond to a scanning operation for performing charged particle imaging. The acquired image may be a single image including multiple imaging regions. The single image may be stored in the memory 294. The single image may be an original image that can be divided into multiple regions. Each region may include an imaging region that includes a feature of the wafer 230. The acquired image may include multiple images of a single imaging region of the wafer 230 sampled multiple times in a time series. The multiple images may be stored in the memory 294. In some embodiments, the image processing system 290 may be configured to perform an image processing step using multiple images of the same position of the wafer 230.

[0058] In some embodiments, the image processing system 290 may include measurement circuitry (e.g., an analog-to-digital converter) to obtain a distribution of the detected secondary charged particles (e.g., secondary electrons). The charged particle distribution data collected during the detection time window combined with the corresponding scan path data of the beamlets 214, 216, and 218 incident on the wafer surface can be used to reconstruct an image of the inspected wafer structure. The reconstructed image can be used to reveal various features of the internal or external structure of the wafer 230, and thus can be used to reveal any defects that may be present in the wafer.

[0059] In some embodiments, the charged particles may be electrons. When the electrons of the primary charged particle beam 210 are projected onto the surface of the wafer 230 (e.g., detection points 270, 272, and 274), the electrons of the primary charged particle beam 210 may penetrate the surface of the wafer 230 to a certain depth and interact with the particles of the wafer 230. Some electrons of the primary charged particle beam 210 may interact elastically with the material of the wafer 230 (e.g., in the form of elastic scattering or collision), and may be reflected or rebounded from the surface of the wafer 230. The elastic interaction conserves the total kinetic energy of the interacting subject (e.g., the electrons of the primary charged particle beam 210), wherein the kinetic energy of the interacting subject is not converted into other forms of energy (e.g., thermal energy, electromagnetic energy, etc.). Such reflected electrons generated by the elastic interaction may be referred to as backscattered electrons (BSE). Some electrons of the primary charged particle beam 210 may interact inelastically with the material of the wafer 230 (e.g., in the form of inelastic scattering or collision). The inelastic interaction does not conserve the total kinetic energy of the interacting subject, wherein part or all of the kinetic energy of the interacting subject is converted into other forms of energy. For example, through inelastic interactions, the kinetic energy of some of the electrons of the primary charged particle beam 210 can cause electron excitation and transition of material atoms. Such inelastic interactions can also generate electrons that leave the surface of the wafer 230, which can be referred to as secondary electrons (SE). The yield or emission rate of BSE and SE depends on, for example, the material being inspected and the landing energy of the electrons of the primary charged particle beam 210 landing on the material surface. The energy of the electrons of the primary charged particle beam 210 can be determined in part by its accelerating voltage (e.g., Figure 2 The number of BSE and SE may be more or less (even the same) than the injected electrons of the primary charged particle beam 210 , depending on the accelerating voltage between the anode and the cathode of the charged particle source 202 .

[0060] The images generated by the SEM can be used for defect inspection. For example, a generated image capturing a wafer test device area can be compared with a reference image capturing the same test device area. The reference image can be predetermined (e.g., by simulation) and does not contain known defects. If the difference between the generated image and the reference image exceeds the tolerance level, potential defects can be identified. For another example, the SEM can scan multiple areas of a wafer, each area including a test device area designed to be the same, and generate multiple images capturing these test device areas of the manufacturing. Multiple images can be compared to each other. If the difference between the multiple images exceeds the tolerance level, potential defects can be identified.

[0061] Figure 3A Schematic diagram showing an exemplary structure of a detector 300A consistent with an embodiment of the present disclosure. The detector 300A can be configured as a charged particle detection device 244. Figure 3AIn the embodiment, the detector 300A includes a sensor layer 301, a partial layer 302 and a readout layer 303. The sensor layer 301 may include a sensor die composed of a plurality of sensing elements, including sensing elements 311, 312, 313 and 314. In some embodiments, a plurality of sensing elements may be arranged in a sensing element array, and each sensing element may have a uniform size, shape and arrangement. The detector 300A may have an arrangement relative to a coordinate axis reference system. The sensor layer 301 may be arranged along an xy plane. The sensing elements in the sensor layer 301 may be arranged along the x-axis and y-axis directions. The x-axis direction may also be referred to as the "horizontal" direction herein. The y-axis direction may also be referred to as the "vertical" direction herein. The detector 300A may have a layer structure in which the sensor layer 301, the partial layer 302 and the partial layer are stacked along the z-axis direction. The z-axis direction may also be referred to as the "thickness" direction herein. The z-axis direction may be aligned with the incident direction of the charged particles toward the detector 300A.

[0062] Partial layer 302 may include multiple parts, including parts 321, 322, 323, and 324. The parts may include interconnects (e.g., wiring paths) configured to communicatively couple multiple sensing elements. The parts may also include switches that can control the communicatively coupling between the sensing elements. The parts may also include connection mechanisms (e.g., wiring paths and switches) between the sensing elements and one or more common nodes in the partial layer. For example, Figure 3A As shown, portion 323 can be configured to be communicatively coupled to the output ends of sensing elements 311, 312, 313, and 314, as shown by the four dotted lines between sensor layer 301 and portion layer 302. In some embodiments, portion 323 can be configured to output the combined signals collected from sensing elements 311, 312, 313, and 314 as a common output. In some embodiments, a portion (e.g., portion 323) can be communicatively coupled to a sensing element (e.g., sensing elements 311, 312, 313, and 314) directly above the portion. For example, portion 323 can have a terminal grid configured to be connected to the outputs of sensing elements 311, 312, 313, and 314. In some embodiments, portions 321, 322, 323, and 324 can be provided in an array structure so that they have uniform size and shape and uniform arrangement. For example, portions 321, 322, 323, and 324 can be square. In some embodiments, an isolation region can be provided between adjacent portions to electrically insulate them from each other. In some embodiments, the portions may be arranged in an offset pattern, such as a tiled layout.

[0063] The readout layer 303 may include a signal processing circuit for processing the output of the sensing element. In some embodiments, a signal processing circuit may be provided that corresponds to each portion of the partial layer 302. In some embodiments, a plurality of separate signal processing circuit portions may be provided, including signal processing circuit portions 331, 332, 333, and 334. In some embodiments, the signal processing circuit portions may be arranged in a partial array having a uniform size and shape and a uniform arrangement. In some embodiments, the signal processing circuit portions may be configured to be connected to the outputs from the corresponding portions of the partial layer 302. For example, Figure 3A As shown, signal processing circuit portion 333 may be configured to be communicatively coupled to the output of portion 323 , as indicated by the dashed line between portion layer 302 and readout layer 303 .

[0064] In some embodiments, readout layer 303 may include input and output terminals. The outputs of readout layer(s) 303 may be connected to components for reading and interpreting the outputs of detector 300A. For example, readout layer 303 may be directly connected to a digital multiplexer, a digital logic block, a controller, a computer, etc.

[0065] The size of the portion and the number of sensing elements associated with the portion may vary. For example, while Figure 3A A 2x2 array of four sensing elements in one section is shown, but embodiments of the present disclosure are not limited thereto. A section may include, for example, an array of 3x3, 4x4, 1x6, or any desired number of sensing elements.

[0066] Although Figure 3A The sensor layer 301, the partial layer 302, and the readout layer 303 are shown as a plurality of separate layers, but it should be noted that the sensor layer 301, the partial layer 302, and the readout layer 303 do not have to be provided as separate substrates. For example, the wiring path of the partial layer 302 may be provided in a sensor die including a plurality of sensing elements, or may be provided outside the sensor die. The wiring path may be patterned on the sensor layer 301. In addition, the partial layer 302 may be combined with the readout layer 303. For example, a semiconductor chip including the wiring path of the partial layer 302 and the signal processing circuit of the readout layer 303 may be provided. Therefore, the structures and functions of the individual layers may be combined or divided.

[0067] In some embodiments, the detector may be provided in a dual die configuration. However, embodiments of the present disclosure are not limited thereto. For example, the functions of the sensor layer, the partial layer, and the readout layer may be implemented in one die, or in a package that may contain one or more dies.

[0068] In some embodiments, the arrangement of sensor layer 301, partial layer 302, and readout layer 303 may correspond to each other in a stacked relationship. For example, partial layer 302 may be mounted directly on top of readout layer 303, and sensor layer 301 may be mounted directly on top of partial layer 302. The layers may be stacked so that a portion in partial layer 302 is aligned with a signal processing circuit portion (e.g., portions 331, 332, 333, and 334) of readout layer 303. In addition, the layers may be stacked so that one or more sensing elements in sensor layer 301 are aligned with a portion in partial layer 302. In some embodiments, a sensing element associated with a portion may be contained within the portion. For example, in a plan view of detector 300A, sensing elements (e.g., sensing elements 311, 312, 313, and 314) of a portion (e.g., portion 323) may fit within the boundaries of the portion. In addition, portions of partial layer 302 may overlap with a portion of the signal processing circuit of readout layer 303. In this way, predefined areas may be established to associate sensing elements with portions and signal processing circuitry.

[0069] Figure 3B FIG. 2 shows an exemplary structure of a sensor surface 300B consistent with an embodiment of the present disclosure, which may form the surface of a charged particle detection device 244. The sensor surface 300B may be provided with a plurality of sensing element portions, including portions 340, 350, 360, and 370, which are indicated by dashed lines. For example, the sensor surface 300B may be Figure 3A Each portion may be capable of receiving at least a portion of a beam spot emitted from a specific location of the wafer 230, such as Figure 2 One of the secondary charged particle beams 236, 238, and 240 is shown.

[0070] Sensor surface 300B may include an array of sensing elements, including sensing elements 315, 316, and 317. In some embodiments, each of portions 340, 350, 360, and 370 may include one or more sensing elements. For example, portion 340 may include a first plurality of sensing elements, portion 350 may include a second plurality of sensing elements, and so on. The first plurality of sensing elements and the second plurality of sensing elements may be mutually exclusive. In some embodiments, the sensing element may be a diode or any diode-like element that is capable of converting incident energy into a measurable signal. For example, the sensing element may include a PIN diode, an avalanche diode, an electron multiplier tube (EMT), or other components.

[0071] exist Figure 3BIn some embodiments, region 380 may be provided between adjacent sensing elements. Region 380 may be an isolation region for isolating the sides or corners of adjacent sensing elements from each other. In some embodiments, region 380 may include an insulating material different from the sensing elements of sensor surface 300B. In some embodiments, region 380 may be provided in a square shape. In some embodiments, region 380 may not be provided between adjacent sides of the sensing elements.

[0072] In some embodiments, a field programmable detector array may be provided with sensing elements having switch regions integrated between the sensing elements. For example, a detector may be provided such as some examples discussed in PCT Application No. PCT / EP2018 / 074833 filed on September 14, 2018, the contents of which are incorporated herein by reference in their entirety. In some embodiments, switch regions may be provided between the sensing elements so that some or more sensing elements may be grouped when covered by the same charged particle beam spot. Circuitry for controlling the switch regions may be included in a readout layer (e.g., Figure 3A In the signal processing circuit of the readout layer 303 in the detector. As used in the present disclosure, the expression "sensing element group" shall mean a first number of sensing element groups. A first set of sensing elements in a set of sensing elements may refer to a subset of sensing elements within the set. A second set of sensing elements may refer to another subset of sensing elements within the set. The first set and the second set may or may not be mutually exclusive. A "group" of sensing elements may refer to sensing elements associated with a beam spot projected on the detector surface (for example, within the boundaries of the beam spot). The first set and the second set of sensing elements may refer to different groups of sensing elements associated with different beam spots. Groups of sensing elements are not necessarily limited to a particular "portion" of the detector.

[0073] Figure 4 is a diagram illustrating an exemplary detector array 400 with switches consistent with embodiments of the present disclosure.

[0074] Figure 4 The architecture can be used for single beam inspection tools or multi-beam inspection tools (e.g., Figure 2 The detector array 400 may be Figure 3A The 4x4 array of portion 421 may have the same Figure 3A For example, the detector array 400 may include a sensor layer (e.g., similar to Figure 3A sensor layer 301 in the embodiment of the present invention), a partial layer (e.g., similar to Figure 3A 302) and a readout layer (e.g., similar to Figure 3AThe sensor layer of the detector array 400 may include a plurality of sensing elements, including a sensing element 411. In some embodiments, each sensing element of the detector array 400 may have a uniform size, shape, and arrangement. The sensing elements of the detector array 400 may generate a current signal commensurate with the charged particles (e.g., emitted electrons) received in the active region of the sensing element. The "active region" herein may refer to a region where the radiation sensitivity of the sensing element is above a predetermined threshold.

[0075] Some layers of the detector array 400 may include a substrate (e.g., a semiconductor substrate, Figure 4 (not shown), the substrate includes one or more wiring paths 402. The wiring paths 402 can be configured to communicatively couple the sensing elements of the detector array 400. Figure 4 As shown, detector array 400 includes portion 421 having a 4×4 array of sensing elements 411 .

[0076] exist Figure 4 In the embodiment of the present invention, a portion of the detector array 400 may include an inter-element switch 415 between any two adjacent sensing elements. A portion of the detector array 400, such as Figure 4 Section 421 (or Figure 3A Sections 321-324 or Figure 3B 340-370 in the cross-section), can be coupled to each other via inter-element switches 415, which are communicatively coupled to the edges of the cross-section. This lateral network of inter-element switches 415 can form part of a "lower level" layer of the switch matrix.

[0077] The wiring path 402 may be configured to be communicatively coupled to the output of the sensing element 411 in the portion 421. For example, the wiring path 402 may have a terminal grid (shown as a circular black dot in the center of the sensing element) that is configured to connect to the output of the sensing element 411. In some embodiments, the wiring path 402 may be disposed in a portion of the layer of the detector array 400. Figure 4 In FIG. 4 , the wiring path 402 is communicatively coupled to the sensing element 411 above it. Figure 4 In some embodiments, the element bus switch 420 may be disposed between the output of the sensing element and the routing path 402. In some embodiments, the element bus switch 420 may be disposed in a partial layer of the detector array 400.

[0078] In some embodiments, the wiring paths 402 may include conductive material lines, flexible lines, bonding wires, etc. printed on a substrate. In some embodiments, switches may be provided so that the outputs of the individual sensing elements may be connected or disconnected from the common output of the portion 421. In some embodiments, some layers of the detector array 400 may also include corresponding circuits for controlling the switches. In some embodiments, the switches may be provided in a separate matrix of switch elements, which may itself contain circuits for controlling the switches.

[0079] The readout layer of the detector array 400 may include a signal conditioning circuit for processing the output of the sensing element. In some embodiments, the signal conditioning circuit may convert the generated current signal into a voltage that may represent the intensity of the received beam spot, or may amplify the generated current signal into an amplified current signal. The signal conditioning circuit may include, for example, an amplifier 404 and one or more analog switches. The amplifier 404 may be a high-speed transimpedance amplifier, a current amplifier, etc. Figure 4 In the embodiment, amplifier 404 can be communicatively coupled to the common output terminal of portion 421 for amplifying the output signal of the sensing element of portion 421. In some embodiments, amplifier 404 can be a single-stage or multi-stage amplifier. For example, if amplifier 404 is a multi-stage amplifier, it can include a pre-amplifier and a post-amplifier, or a pre-stage and a post-stage, etc. In some embodiments, amplifier 404 can be a variable gain amplifier, such as a variable gain transimpedance amplifier (VGTIA), a variable gain charge transfer amplifier (VGCTA), etc. The regulation circuit can be coupled to a signal path, which can include, for example, an analog-to-digital converter (ADC) 406. In the embodiment, amplifier 404 can be a single-stage or multi-stage amplifier. Figure 4 406 can be communicatively coupled to the output of a conditioning circuit (e.g., including amplifier 404) to convert the analog output signals of the sensing elements of portion 421 into digital signals. The readout layer of detector array 400 can also include other circuits for other functions. For example, the readout layer of detector array 400 can include a switch element actuation circuit that can control switches between sensing elements. For ease of explanation and without ambiguity, the signal path between the sensing elements and ADC 406 can be referred to as an "analog signal path." For example, Figure 4 The analog signal path in the detector 400 includes the above-mentioned signal conditioning circuit (e.g., including amplifier 404). The input of the analog signal path is communicatively coupled to the sensing element, and the output of the analog signal path is communicatively coupled to ADC 406. The signal path between the sensing element and the readout layer can be referred to as a "signal readout path" and can be the same as or different from the analog signal path. For example, the signal readout path can include an analog signal path or multiple analog signal paths, and can be further extended into the readout layer of the detector 400, such as to a digital multiplexer 408.

[0080] In some embodiments, ADC 406 may include an output that is communicatively coupled to a component (e.g., a component internal or external to a readout layer of detector array 400) for reading and interpreting the digital signal converted by ADC 406. Figure 4 4, ADC 406 is communicatively coupled to digital multiplexer 408. In some embodiments, digital multiplexer 408 can be disposed in a readout layer of detector array 400. Digital multiplexer 408 can receive multiple input signals and convert them into output signals. The output signal of digital multiplexer 408 can be converted back into multiple input signals. The output signal of digital multiplexer 408 can be further transmitted to a data processing stage (e.g., Figure 2 Image processing system 290 in.

[0081] In some embodiments of the present disclosure, the detector 400 may include another switch layer, such as an interconnect layer 416, which communicatively couples the outputs of the signal processing circuit to each other. The signal processing circuit may include an analog signal path. As used in this specification and the appended claims, the action of closing a switch (or keeping the switch in a closed state) to allow charge to flow through the switch may be referred to as "enabling" the switch. Similarly, the action of disabling the switch (or keeping the switch in an open state) to prevent charge from flowing through the switch may be referred to as "disabling" the switch.

[0082] like Figure 4 As shown, interconnect layer 416 includes interconnect switches that are communicatively coupled to outputs of analog signal paths of detector array 400. For example, interconnect switches 430-433 may be communicatively coupled to outputs of adjacent analog signal paths from adjacent portions of sensing element 411. Detector array 400 includes analog signal path 405 associated with portion 421 that begins at the output of portion 421 and ends at an input of interconnect layer 416.

[0083] Interconnect switches 430-433 within interconnect layer 416 may form part of a "higher level" layer of the switch matrix. The interconnect switches may form a repeating unit corresponding to each sensing element portion. For example, interconnect switches 430 and 431 may form a repeating unit in interconnect layer 416 corresponding to portion 421. Figure 4In the direction of the detector 400, interconnect switch 430 may form a top switch, coupling portion 421 to another sensing element portion "above" it in the plane of the detector 400 (not shown), while interconnect switch 431 may form a right switch, coupling portion 421 to another sensing element portion to the right of the plane (also not shown). Similarly, interconnect switch 433 may form a right switch from the portion to the left of portion 421, while interconnect switch 432 may form a top switch from the portion below portion 421 in the plane of the detector 400. Since each interconnect switch is actually shared by two adjacent portions, rather than belonging to a specific portion, the naming scheme is arbitrary. Each element bus switch 420 may connect its respective sensing element 411 to the interconnect layer 416, as well as any other sensing elements that have been connected to the respective sensing element via the inter-element switch 415. Thus, the element bus switch 420 may serve as a connection between the inter-element switch 415 network in the lower level and the interconnect switch 430-433 network in the higher level.

[0084] exist Figure 4 409 can communicatively couple the output of portion 421 to the input of analog signal path 405, and switch 410 can communicatively couple the output of analog signal path 405 to the input of interconnect layer 416 (e.g., input / output point 426 or "I / O point" 426). If analog signal path 405 is not selected for use, switches 409 and 410 can be configured to be communicatively disconnected. For example, a charged particle beam may hit some or all of the sensing elements of portion 421, but the detection signal of portion 421 may be redirected to another analog signal path corresponding to another portion of detector array 400, as discussed further below. In this case, analog signal path 405 may be disconnected due to being unselected. In some embodiments, if the sensing elements of portion 421 are not hit by any charged particles and analog signal path 405 is not selected for use (e.g., to process signals from other portions), in addition to communication disconnect switches 409 and 410, amplifier 404 can also be disabled to reduce power consumption. When switches 409 and 410 are communicatively disconnected, analog signal path 405 (including amplifier 404 ) may be effectively disabled from detector array 400 .

[0085] The switch matrix includes, for example, inter-element switches 415, element bus switches 420, and interconnect switches 430-433, and can be configured to route signals from the sensing elements to the readout layer of the detector array 400 through various signal readout paths. For example, when only one beam spot is incident on portion 421, the sensing elements can be directly coupled to the readout layer through element bus switch 420 and switches 409-410. For example, if it has been previously determined that the beam spot is incident on all sensing elements in portion 421 (e.g., during a "photo mode" discussed below), the entire portion can be coupled to the signal readout path through the element bus switch at each sensing element in portion 421. The inter-element switches 415 between the sensing elements in portion 421 can be kept open to reduce parasitic parameters, such as series resistance and parasitic capacitance. For example, if it is determined that Figure 4 If sensing element 411 in portion 421 is receiving a portion of the beam spot while the remaining sensing elements in portion 421 are not receiving it, then only that sensing element can be connected by enabling its element bus switch 420 while the remaining sensing elements are disconnected by keeping their own element bus switches open.

[0086] At the same time, adjacent sensing elements from adjacent sections can be coupled to a common signal readout path with section 421 at interconnect layer 416. For example, if the beam spot is incident on section 421 and the adjacent section to the left of section 421 ( Figure 4 4 (not shown), adjacent sense elements from adjacent sections may be coupled to interconnect layer 416 via their respective element bus switches 420, and sense element 411 of section 421 may do the same via its own element bus switch 420 (and any intermediate switches, such as input / output switches 409 / 410 at amplifier 404). The two sections may be coupled to a common analog signal path, for example, by enabling interconnect switch 433 and ADC switch 412.

[0087] Alternatively, an adjacent sensing element from an adjacent section may be coupled to section 421 by enabling an inter-element switch 415 between an external sensing element 411 of section 421 and an adjacent sensing element from an adjacent section. This will be further described below, for example, with respect to Fig. 10C In this case, since the signals from the adjacent sensing elements are routed along the lower-level inter-element switches, the element bus switch 420 of the adjacent section can be opened to reduce parasitic parameters. The interconnection switch 433 can also be opened. The signals from the section 421 and the adjacent section can be routed to the ADC 406 through the element bus switch 420, the wiring path 402, the analog signal path 405, and the I / O point 426.

[0088] Another case is when two different beam spots are incident on two different portions of a single sensing element portion, such as portion 421. In this case, the signals from the two beam spots must be routed along different signal readout paths in order to distinguish them. If both portions are coupled to the analog signal path 405, the signals may not be distinguishable. For example, the first beam spot may be incident on the sensing element actually labeled 411, and the adjacent portion to the left of portion 421 discussed above. The second beam spot may be incident on the entire row 417 of sensing elements to the right, and Figure 4 Another adjacent section (not shown) to the right of section 421. If both sets of sensing elements in section 421 were routed through analog signal path 405, their signals would be indistinguishable. Therefore, at least one section may be connected to an adjacent section with which it shares a common beam spot.

[0089] Figure 4 The inter-element switch on the left side of the part 421 is connected to the adjacent part on the left side of the part 421. Then, the adjacent part on the left side can be connected along the Figure 4 In addition, the interconnection switch 433 can be opened to disconnect the adjacent portion from the signal readout path including the analog signal path 405, and the element bus switch 420 under the sensing element actually marked as 411 can also be opened. At the same time, the row 417 can be coupled to the analog signal path 405 through the element bus switch 420 corresponding to each sensing element 411 within the row 417. The analog signal path 405 can be connected to the analog signal path of the adjacent portion on the right by, for example, enabling the interconnection switch 431. Therefore, the row 417 can be coupled to the adjacent portion on its right without enabling the inter-element switch 415 on the right side of the row 417.

[0090] The decision to route the two portions in the exemplary manner described above can be determined based on, for example, a desire to minimize parasitics in the system. For example, if a parallel path along the element bus switches 420 is preferred over a series path along the inter-element switches 415, then a route can be determined such that fewer inter-element switches 415 are connected to the system. In general, the overall measure of parasitics can be considered in determining the optimal signal readout path.

[0091] Additional details of the detector array 400 may be found in U.S. transient patent application No. 63 / 019,179, which is incorporated herein by reference in its entirety.

[0092] Figure 5 5 is a diagram showing a cross-sectional view of a layer structure of a detector 500 consistent with an embodiment of the present disclosure. The detector 500 may be configured as a charged particle detection device 244 in a charged particle beam tool 104, such as Figure 2As shown. The detector 500 may be configured to have a plurality of layers stacked in a thickness direction, the thickness direction being substantially parallel to the incident direction of the charged particle beam. In some embodiments, the detector 500 may be configured as some of the examples discussed in PCT Application No. PCT / EP2018 / 074834 filed on September 14, 2018, the contents of which are incorporated herein by reference in their entirety.

[0093] exist Figure 5 In the embodiment, the detector 500 may include a sensor layer 510 and a circuit layer 520. In some embodiments, the sensor layer 510 may represent Figure 3A The sensor layer 301 in FIG. 5 , and the circuit layer 520 may represent Figure 3A The circuit layer 520 may include a portion of the layer 302 and the readout layer 303. For example, the circuit layer 520 may include interconnects (e.g., metal wires) and various electronic circuit elements. As another example, the circuit layer 520 may include a processing system. The circuit layer 520 may also be configured to receive an output current detected in the sensor layer 510. In some embodiments, the sensor layer 510 may represent Figure 3A The sensor layer 301 and the partial layer 302 in FIG. 5 , and the circuit layer 520 may represent Figure 3A In some embodiments, the detector 500 may further include layers other than the sensor layer 301 , the partial layer 302 , and the readout layer 303 .

[0094] In some embodiments, the sensor layer 510 may be provided with a sensor surface 501 for receiving incident charged particles. Sensing elements may be provided in the sensor layer 510, including sensing elements 511, 512, and 513 (distinguished by dashed lines). For example, the sensor surface 501 may be similar to Figure 3B The sensor surface 300B in Figure 5 In the embodiment, switches may be provided between adjacent sensing elements in the horizontal direction in the cross-sectional view, including switches 519 and 521. Switches 519 and 521 may be embedded in sensor layer 510. In some embodiments, sensing elements 511, 512, and 513 may be Figure 4 One of the sensing elements 411 of the detector 400, switches 519 and 521 may be Figure 4 One of the switches 415 between the sensing elements of the detector array 400 in FIG.

[0095] In some embodiments, the sensing elements 511, 512, 513 may be isolated from each other by an isolation region (shown by a dotted line) extending in the thickness direction. For example, the edges of the sensing elements 511, 512, 513 parallel to the thickness direction may be isolated from each other by an isolation region (for example, Figure 3B The regions 380) in are isolated from each other.

[0096] In some embodiments, sensor layer 510 may be configured as one or more diodes, wherein sensing elements 511, 512, and 513 are similar to Figure 3B The sensing elements 315, 316 and 317 of the sensor layer 510 are shown in FIG. 1 . The switches 519 and 521 may be configured as transistors (e.g., MOSFETs). Each of the sensing elements 511, 512, 513 may include an output terminal for electrically connecting to the circuit layer 520. For example, the output terminal may be integrated with the switches 519 and 521, or may be provided separately. In some embodiments, the output terminal may be integrated in the bottom layer (e.g., metal layer) of the sensor layer 510.

[0097] although Figure 5 Sensing elements 511, 512, and 513 are depicted as separate units in cross section, but this division may not actually be physical. For example, the sensing element of detector 500 can be formed by a semiconductor device forming a PIN diode device, which can be manufactured as a substrate with multiple layers, including a P-type region, an intrinsic region, and an N-type region. In such an example, sensing elements 511, 512, 513 can be continuous in a cross-sectional view. In some embodiments, switches (e.g., switches 519 and 521) can be integrated with the sensing element.

[0098] In some embodiments, the switch may be integrated within the sensor layer, integrated within other layers, or may be partially or fully disposed within an existing layer. In some embodiments, for example, the sensor layer may contain wells, trenches, or other structures in which switches are formed.

[0099] In some embodiments, the switches of the detector 500 (eg, switches 519 and 521) may be disposed outside the sensor layer 510. For example, the switches may be embedded in the circuit layer 520 (eg, Figure 5 In some embodiments, the switches of detector 500 (eg, switches 519 and 521) may be formed in separate dies (eg, switch dies). Figure 5 ) may be sandwiched between the sensor layer 510 and the circuit layer 520 and be communicatively connected thereto.

[0100] Figure 6 is a diagram showing a cross-sectional view of a sensing element 512 of a detector 500 consistent with an embodiment of the present disclosure. Figure 6 In the embodiment, the sensing element 512 may include a P-well and an N-well for forming switches and other active or passive elements that may be communicatively coupled to other components of the sensor layer 510 or the circuit layer 520. Figure 6Only one complete sensing element 512 is shown, but it is understood that the sensor layer 510 may be composed of multiple sensing elements similar to the sensing element 512 (eg, sensing elements 511 and 513 ), which may be continuous in the cross-sectional view.

[0101] In some embodiments, the sensing element 512 may include a diode device having a surface layer 601, a P-type region 610, a P-epitaxial region 620, an N-type region 630, and other components. The surface layer 601 may form a detection surface (e.g., an active region) of a detector that receives incident charged particles. For example, the surface layer 601 may be a metal layer (e.g., formed of aluminum or other conductive materials). On the opposite side of the surface layer 601, an electrode 650 may be provided as a charge collector. The electrode 650 may be configured to output a current signal representing the number of charged particles received in the active region of the sensing element 512.

[0102] like Figure 6 As shown, switches 519 and 521 may be formed by metal oxide semiconductor (MOS) devices. Figure 6 A plurality of MOS devices are formed on the back side of the N-type region 630, and the back side of the N-type region 630 can be connected to Figure 5 The sensor layer 510 in the embodiment of the present invention is contacted. As an example of a MOS device, a deep P well 641, an N well 642, and a P well 643 may be provided. In some embodiments, the MOS device may be manufactured by etching, patterning, and other processes and techniques. It is understood that various other devices may be used, such as bipolar semiconductor devices, etc., and the device may be manufactured by various processes.

[0103] Figure 2 When the secondary charged particle beam 236, 238 and 240 in the sensing element 512 hits the surface layer 601, the body of the sensing element 512 (including, for example, the depletion region) may be filled with charge carriers generated by the impacting charged particles. Such a depletion region may extend through at least a portion of the volume of the sensing element. For example, the charged particles may be electrons, and the impacting electrons may create and excite electron-hole pairs in the depletion region of the sensing element. The excited electrons in the electron-hole pairs may have additional energy so that they can also generate new electron-hole pairs. The electrons generated by the impacting charged particles may contribute to the signal generated in each sensing element.

[0104] refer to Figure 6, the depletion region in the sensing element 512 may include an electric field between the P-type region 610 and the N-type region 630, and the electrons and holes may be attracted by the P-type region 610 and the N-type region 630, respectively. When the electron reaches the P-type region 610 or when the hole reaches the N-type region 630, a detection signal may be generated. Therefore, when the charged particle beam is incident on the sensing element 512, the sensing element 512 may generate an output signal, such as a current. A plurality of sensing elements may be connected, and a sensing element group may be used to detect the intensity of the charged particle beam spot. When the charged particle beam spot covers a plurality of adjacent sensing elements (e.g., sensing elements 511, 512, and 513), the sensing elements may be grouped together ("merged") to collect current. For example, the sensing elements may be merged by opening switches between the sensing elements (e.g., switches 519 and 521). Signals from the sensing elements in the group may be collected and sent to a signal conditioning circuit connected to the group. The number of sensing elements in the group may be any number related to the size and shape of the beam spot. The number may be 1 or greater than 1.

[0105] In some embodiments, the detector can be configured so that individual sensing elements can communicate with external components through, for example, signal or data lines and address signals. The detector can be configured to actuate a switch so that two or more sensing elements can be combined and their output currents or voltages can be combined. Figure 5-Figure 6 As shown, by using the switch element design between the sensing elements, no physical isolation area (e.g., Figure 3B Thus, when the sensing element 512 is activated, all areas under the surface layer 601 may become active. When no physical isolation area is provided between adjacent sensing elements, the dead zone between them may be minimized or eliminated.

[0106] Figure 7 is a diagram showing an exemplary cross-sectional arrangement of a detector 700 consistent with an embodiment of the present disclosure. For example, the detector 700 may be Figure 3A Detector 300A in Figure 4 The detector array 400 or Figure 5 An embodiment of the detector 500 in FIG. Figure 7 As shown, the detector 700 may include a plurality of sensing elements, including a sensing element 711, such as sensing elements 711a-711n. In some embodiments, the plurality of sensing elements may be part of a sensor layer, which may form a Figure 2 The detection surface of the charged particle detection device 244 in Figure 3B The sensor layer may include switches between adjacent sensing elements (e.g., similar to Figure 6519 and 521 in the sensing element), including an inter-element switch 715. In some embodiments, when the switch is turned on, the switch can be configured to combine two or more adjacent sensing elements together.

[0107] exist Figure 7 In the embodiment, the detector 700 may include multiple parts (e.g., similar to Figure 3A Each portion may include one or more sensing elements, and wiring paths between the sensing elements (e.g., similar to Figure 4 In some embodiments, the wiring path may include a common line or a shared signal path. For example, Figure 7 As shown, wiring path 702a can be communicatively connected to sensing element 711a, and common output terminal 728a. Wiring path 702a, sensing element 711a, and common output terminal 728a can belong to a first portion. Wiring path 702b can be communicatively connected to sensing element 711b, and common output terminal 728b. Wiring path 702b, sensing element 711b, and common output terminal 728b can belong to a second portion. In general, the detector can have any number of portions ( Figure 7 denoted by "n" in the figure), where corresponding components share the same number and different letters. Letters may be omitted when referring generally to all such components (e.g., "sensing element 711" may refer to sensing element 711a, sensing element 711b, sensing element 711n, etc.). The output (e.g., output terminal 719) of a sensing element (e.g., rightmost sensing element 711b) may be communicatively coupled to a corresponding wiring path (e.g., wiring path 702b) via an element bus switch (e.g., element bus switch 720). In some embodiments, element bus switch 720 may be used similar to Figure 6 In some embodiments, when the sensing element 711b is in an inactive state, the element bus switch 720 can be turned off to reduce noise, parasitic capacitance or other technical effects of the sensing element and related circuits.

[0108] exist Figure 7 In the embodiment, each portion (e.g., the first portion including the sensing element 711a or the second portion including the sensing element 711b) can be configured to output electrical signals to the signal processing circuit and other circuit elements. For example, the wiring path 702 can output electrical signals to the signal processing circuits 704-706 through the common output terminal 728.

[0109] The signal processing circuit may include one or more signal processing circuits for processing the electrical signal output by the wiring path 728. For example, the signal processing circuits 704-706 may include an amplifier 704 (including, for example, a preamplifier and a postamplifier) ​​and a data converter 706. Examples of preamplifiers include transimpedance amplifiers (TIA), charge transfer amplifiers (CTA), current amplifiers, etc. Examples of postamplifiers include variable gain amplifiers (VGA), etc. The data converter 706 may be an analog-to-digital converter (ADC), which can convert an analog voltage or an analog current into a digital value. In some embodiments, the preamplifier and the postamplifier may be combined into a single amplifier 706 (for example, Figure 4 404 in the amplifier), and the data converter 706 may include Figure 4 ADC406 in.

[0110] The detector 700 may include a digital switch 708. In some embodiments, the digital switch 708 may include a matrix of switch elements. In some embodiments, the digital switch 708 may include a multiplexer (e.g., Figure 4 For example, the multiplexer may be configured to receive a first number of inputs and generate a second number of outputs, where the first number and the second number may be the same or different. The first number may correspond to a parameter of the detector 700 (e.g., the total number of parts), and the second number may correspond to Figure 1-2 The parameters of the beam tool 104 (e.g., from Figure 2 The digital switch 740 can communicate with external components via data lines and address signals. In some embodiments, the digital switch 740 can control data read / write. The digital switch 740 can also include circuitry for controlling the inter-element switch 715. Figure 7 In the embodiment, the digital switch 740 can generate an output signal through multiple data channels, including data channels 751a-n. In some embodiments, the data channels of the digital switch 708 can be further connected to other components (e.g., relays, etc.). Therefore, multiple parts of the detector 700 can act as independent data channels for the detector signal.

[0111] It is worth noting that in Figure 7 Various components are inserted at various stages in the representation of the detector 700. In some embodiments, one or more of the above components of the detector 700 may be omitted. In some embodiments, other circuits may be provided to achieve other functions. For example, a switch element actuation circuit ( Figure 7 (not shown) to control the inter-element switch 715 for connecting the sensing elements. In some embodiments, an analog output line ( Figure 7706 ), which can be read by the analog path. For example, the analog output line can be parallel to the data converter 706 to receive the output of the post amplifier. For another example, the analog output line can replace the data converter 706.

[0112] Figure 4 Similar to the interconnect layer 416 in FIG. 7 , the detector 700 may include an interconnect layer 716 (represented by a dashed box) disposed between the amplifier 704 and the ADC 706. The amplifier 704 may be communicatively coupled to the interconnect layer 716 via a switch 710, which may be similar to Figure 4 The interconnect layer 716 can be communicatively coupled to the ADC via the switch 712, which can be similar to Figure 4 In some embodiments, switches 709, 710, 712, and 731-733 may be used similar to Figure 6 This is achieved using the technology of switches 519 and 521 described in .

[0113] Interconnect layer 716 may include a plurality of outputs, including I / O point 726. In some embodiments, I / O point 726 may be similar to Figure 4 In some embodiments, each amplifier 704 of the detector 700 can be communicatively coupled to an input 726 of the interconnect layer 716 via a switch 710. In some embodiments, each ADC 706 of the detector 700 can be communicatively coupled to an output (e.g., an I / O point 726) of the interconnect layer 716 via a switch 712.

[0114] exist Figure 7 , the interconnect layer 716 includes interconnect switches (e.g., interconnect switches 731-733) communicatively coupled to the outputs of the amplifiers, which may be similar to Figure 4 In some embodiments, the interconnection switches in the interconnection layer 716 may be similar to Figure 6 This is accomplished using the techniques for switches 519 and 521 described in .

[0115] In some embodiments, to increase the pixel rate, the ADC of the detector 700 can be configured to operate in an interleaved mode. Typically, when the ADC operates in an interleaved mode, two or more ADCs can be communicatively coupled to a clock circuit. The clocks of the ADCs can be set to have a predetermined relationship. When operating, the ADCs can alternately sample ("interleave") input signals and generate a combined output signal. The pixel rate of the combined output signal can be higher than the pixel rate achieved by each individual ADC. For example, when m (m is an integer) ADCs are configured to operate in an interleaved mode, where each ADC has a pixel rate of n (n is a number) pixels per second, the combined pixel rate of the m ADCs can be m×n pixels per second.

[0116] For example, a clock circuit ( Figure 7 Not shown) and control circuit ( Figure 7 Each ADC, including ADC 706a-n, can be set to clock control. The clock control circuit can be communicatively coupled to the clock circuit and can set different timing offsets for each ADC with reference to the clock signal generated by the clock circuit. The input terminals of the ADC can be communicatively coupled through switches in the interconnect layer 716, and the control circuit can control them to operate in an interleaved mode.

[0117] In some embodiments, for applications requiring a pixel rate higher than the pixel rate supported by the maximum sampling rate of the ADC of the detector 700, the ADC can be configured to operate in an interleaved mode. For example, ADCs 706a and 706b can have the same maximum sampling rate. When wiring path 702a is activated (e.g., due to a charged particle beam striking sensing element 711a), switches 709a and 710a can be communicatively connected to enable the signal output by wiring path 702a to be processed and amplified by amplifier 704a. Interconnection switch 731 and switches 712a and 712b can coordinate to transfer the amplified signal output by amplifier 704a to ADCs 706a and 706b in an alternating manner. For example, by communicatively connecting switch 712a and communicatively disconnecting interconnection switch 731 and switch 712b, the amplified signal output by amplifier 704a can be transferred to ADC 706a. By communicatively disconnecting switch 712a and communicatively connecting interconnection switch 731 and switch 712b, the amplified signal output by amplifier 704a can be transferred to ADC 706b. Control circuits and clock circuits may control the timing of such transfers and the sampling timing of ADCs 706a and 706b. The effective sampling rate of the combined output signal of ADCs 706a and 706b may be twice the maximum sampling rate of any single ADC.

[0118] It should be noted that more than two ADCs of the detector 700 can be configured in a similar manner to operate in an interleaved mode, and the present disclosure does not limit the embodiments of the interleaved mode to the above examples. In some embodiments, the communication-coupled ADCs of the detector 700 operating in an interleaved mode can be adjacent to or not adjacent to each other. For example, ADCs 706a, 706b, and 706n can be configured to operate in an interleaved mode, wherein the interconnection switches (e.g., including interconnection switches 731) and switches 712a-n of the interconnection layer 716 between them can coordinate to transfer the amplified signal output by the amplifier 704b to ADCs 706a-n in an alternating manner. For example, the amplified signal output by the amplifier 704b can be transferred to the ADC 706a through the communication connection switch 712a and the interconnection switch 731, as well as the communication disconnection switch 712b, the switch 712n, and one or more interconnection switches between the ADCs 706b and 706n. The amplified signal output by the amplifier 704b can be transferred to the ADC 706b through the communication connection switch 712b, and the communication disconnection switch 712a, the switch 712n, the interconnection switch 731, and one or more interconnection switches between the ADCs 706b and 706n. The amplified signal output by the amplifier 704b can be transferred to the ADC 706n through the communication connection switch 712n and all interconnection switches between the ADCs 706b and 706n and the communication disconnection switch 712a, the switch 712b, and the interconnection switch 731.

[0119] In some embodiments, when the beam impinging on the detector 700 has a large beam spot, multiple analog signal paths of the detector 700 can be configured to be communicatively coupled to a single ADC 706 via an interconnect layer 716. For example, analog signals from different analog signal paths can be summed or combined by hardware (e.g., at the interconnect layer 716) before being input to any ADC 706. The summed analog signal can be converted by a single ADC 706. Such a design can reduce the required digital output bandwidth and increase configuration flexibility. In contrast, existing detector designs may lack the ability to perform hardware-based analog signal summing before signal digitization (e.g., because the analog signal path does not have the ability to output its signal to an ADC in other signal paths), and may require multiple digital output channels or bandwidths to process signals from the same large beam spot. Compared to existing designs, the design of the detector 700 can provide higher analog signal bandwidth without requiring additional digital output capacity or causing a significant increase in the size of the readout circuit, because a single ADC is sufficient to process the analog signal that is summed with analog signals from multiple analog signal paths before its input.

[0120] Although Figure 7A full set of processing circuits 704-706 for each section is shown, but this may not always be the case. In some embodiments of the present disclosure, each section in a section array (e.g., a 2x2 array) may have a dedicated amplifier 704, but there may be only one ADC 706 in the entire 2x2 section array. For example, in each 2x2 section array, there may be only one section that has a direct (or "vertical") connection to the ADC 706. In this case, any sensing elements 711 within the remaining three sections must be connected laterally (e.g., through inter-element switches 715 in the lower level or interconnect switches 731-733 in the higher level) to a section with such processing circuits in order to read out their signals (although it does not have to be the processing circuits within their same section array). Alternatively, the section array may have only one amplifier as well as one ADC. Here, an amplifier can be located downstream of the I / O point 726 to allow amplification of signals transferred along the higher and lower levels, which are then passed to the ADC 706. Thus, in a detector divided into 2x2 arrays, each array having four sections, each section comprising a 4x4 array of, for example, 16 sensing elements, each channel of processing circuit 706 (or 704-706) may have an 8x8 grid of 64 sensing elements. It should be understood that the number of sections and sensing elements in this paragraph is given by way of example only.

[0121] For example, in some embodiments of the present disclosure, the first portion of sensing elements 711a and the second portion of sensing elements 711b may include 2 portion rows in a 2x2 portion array. The first portion may include a direct (or "vertical") path to the processing circuits 704a-706a, while the second portion may not include Figure 7 For example, ADC 706b or both amplifier 704b and ADC 706b may be omitted (in the latter case, amplifier 706a may be located in Figure 7 In this case, the signal from the sensing element 711b can be passed to the processing circuit of another part (such as ADC 706a or 706n) by using a lateral switch (such as inter-element switch 715 or interconnect switches 731-733).

[0122] Figure 8 is a diagram showing a detection system 800 consistent with an embodiment of the present disclosure. In some embodiments, the detection system 800 may be Figure 2 Detection system 800 may include a sensing element 802 (e.g., similar to Figure 3A-Figure 7 ) and processing circuit 840 (e.g., similar to Figure 7Processing circuit 840 may be communicatively coupled to digital interface 850 (e.g., similar to Figure 7 The sensing element 802 may form a sensor surface (e.g., Figure 3B sensor surface 300B), and may be segmented into a plurality of portions (e.g., similar to Figure 3A-3B or Figure 7 The processing circuit 840 may include a first processing circuit array 810 (eg, including Figure 7 The preamplifier discussed above) is used to process the output of the sensing element 802; the second processing circuit array 820 (for example, including Figure 7 discussed post amplifier) ​​for providing gain and offset control; and an ADC array 830 (e.g., including Figure 7 The data converter 706 in the processing circuit 840 is used to convert the analog signal into a digital signal. The first processing circuit array 810 and the second processing circuit array 820 may form a signal conditioning circuit in the processing circuit 840. Each portion of the processing circuit 840 may be communicatively coupled to a portion of the sensing element 802, and the sensing element 802 may be communicatively coupled to the units of the first processing circuit array 810, the units of the second processing circuit array 820, and the units of the ADC array 830 in turn, thereby forming a signal path (e.g., signal path 860). Such a signal path may receive an output signal from the sensing element portion 802 and generate a charged particle detection current that represents the intensity of at least a portion of the charged particle beam spot formed on the sensing element portion 802. The charged particle detection data may be output to the digital interface 850. In Figure 8 , signal path 860 includes an analog signal path 870 that includes cells of the first processing circuit array 810 and cells of the second processing circuit array 820 .

[0123] The digital interface 850 may include a controller 804. The controller 804 may communicate with the ADC array 830, the second processing circuit array 820, and the sensing element 802. The digital interface 850 may also send and receive signals from the deflection and image control unit ( Figure 8 The transceiver may include a transmitter 806 and a receiver 808. In some embodiments, the controller 804 may control image signal processing of the detection system 800.

[0124] The detector can be configured to run in a number of different operating modes. For example, there may be a first mode called "photo mode" that is used to associate a portion of the detector surface with a specific beam spot. The detector may include a large number of small sensing elements in a pixelated array. These sensing elements can be connected to each other in groups through a switch matrix to form a combined signal when detecting an electron beam spot. However, when the sensing elements are grouped together by enabling switches between them, it is impossible to know exactly which sensing element any part of the signal comes from. Therefore, each connected group should include only those elements that are expected to receive the same beam spot. Photo mode is a process for determining the size, shape, and position of each beam spot on the detector surface in order to know which sensing elements should be grouped with each other (called "beam mode") during normal detection.

[0125] In the photo mode, the detector surface may be illuminated by the secondary beam spot while the output of each sensing element in the pixelated array is read individually. These individual readings can be used to determine each location on the detector surface that receives a portion of the beam spot. An image (e.g., a secondary electron beam projection image) can be formed that represents a fine-grained projection pattern of the secondary beam spot on the detector surface. That is, a fine-grained image of the entire detector surface is generated. Based on the image, groups of sensing elements can be selected so that the size, shape, and position of each group substantially matches the size, shape, and position of one of the beam spots on the detector surface. These selected groups of sensing elements can later be used to detect their respective beam spots in the beam mode.

[0126] In "beam mode", for example during an inspection process, the sensing elements within each determined group are coupled to each other via a switch matrix, and their outputs can be combined with each other to obtain an intensity measurement of the secondary beam spot associated with the group. Thus, photo mode can be used to determine the boundaries of desired sensing element groupings that can be used during an inspection process in beam mode. The switch matrix used to interconnect the sensing elements may include circuits such as switches, wiring paths, and logic components between the sensing elements and readout circuits of the detector. In beam mode, processing speed may be more important than high resolution. Due to "parasitic" effects, processing speed may be reduced by the number of circuit elements electrically connected to the system during inspection and how they are connected. The more sensing elements, switches, etc., connected to the group during inspection, the more severe the parasitic effects may become.

[0127] The switch matrix according to an embodiment of the present invention can be configured to have better bandwidth performance than the comparative switch matrix embodiment. For example, the detector in the comparative embodiment can be configured to use different routing paths for different operating modes (such as photo mode and beam mode). Different paths may include additional switches that can increase parasitic parameters in the system. In addition, some configurations in the comparative embodiments may require the use of many lateral inter-element switches in series when routing signals from sensing elements along analog signal paths. This series configuration increases parasitic parameters not only due to the series connection, but also due to the requirements imposed on the circuit elements by such operation. For example, when many sensing elements are expected to be connected in series, the switches can be made larger to reduce the on-resistance of the series switches.

[0128] Figure 9A-9C These problems are shown in connection with a detector architecture according to a comparative embodiment. Fig. 9A A portion 921 of the detector 900 having a 4x4 array of sensing elements and associated circuitry is shown (enclosed by a dashed box, similar to Figure 4 Portion 421 in FIG. 4A ). Portion 921 may be communicatively coupled to one or more other portions of detector array 900. Fig. 9A , portion 921 is communicatively coupled to four adjacent (or "neighboring") portions ( Fig. 9A (not shown in FIG. 1 ). In this document, two "adjacent" objects along a direction may refer to two objects along that direction without an intermediate object between them. Such objects may be, for example, parts or sensing elements.

[0129] Portion 921 may include a 4×4 array of sensing elements (e.g., similar to Figure 3A Any one of the sensing elements 321-324 in Figure 5-Figure 6 Any one of the sensing elements 511-513 in Figure 7 11a-11n in the sensing element 711a-11n). The sensing elements can be communicatively coupled to each other and various signal paths through switches and other circuit elements. Sensing element circuits (e.g., a unit including sensing elements and related switching elements and other circuits) 914a and 914b are adjacent in the vertical direction (e.g., the y-axis). Fig. 9A As shown, each sensing element circuit 914 within portion 921 can have the same structure and operate in the same manner, except for sensing element circuit 914 b. Other portions of detector 900 can have the same or similar configuration as portion 921.

[0130] Portion 921 may also include an output bus 902 (indicated by a thick black line), which is a shared signal bus for receiving individual detection signals generated by the sensing elements. Output bus 902 may output the received signals independently to a portion of the signal path or readout circuit via bus output 941. Fig. 9A As shown, the output bus 902 can output the signal to the partial circuit 903. The partial circuit 903 can be, for example, included in Figure 3A In any one of the parts 321-324 in the bus output 941. A photo pickup switch 942 can be arranged between the bus output terminal 941 and the partial circuit 903. In some embodiments, when there is no signal output at the bus output terminal 941, the photo pickup switch 942 can be set to be communication disconnected (e.g., open) to reduce parasitic parameters in signal processing. Another common output terminal 918 can be communicatively coupled to the node 926 through the partial pickup switch 943. In some embodiments, the node 926 can be arranged in a sensor layer (e.g., Figure 3A In the sensor layer 301).

[0131] Fig. 9B According to the comparative example, Fig. 9A Detailed views of sense element circuits 914a and 914b in FIG. Except for sense element circuit 914b, all sense element circuits in portion 921 may form a repeating unit similar to sense element circuit 914a.

[0132] The sensing element circuit 914a may include a sensing element 911 (e.g., a PIN diode), a photo mode switch 920, an inter-element switch 915 (e.g., an upper element switch 915u and a right element switch 915r), a ground switch 925, and a ground 927. The sensing element 911 of the comparative embodiment may correspond to, for example, Figure 3A Sensing elements 311-314, Figure 3B Sensing elements 315-317, Figure 4 The sensing element 411, Figure 5 and Figure 6 The sensing elements 511-513 or Figure 7 711a-n of the sensing element 911a-n. The sensing element 911 can be coupled to the signal readout path (activation) via, for example, enabling the photo mode switch 920 or the inter-element switch 915, as discussed further below. The inter-element switch 915 can form a lower level lateral switch network of the switch matrix. For example, by enabling the ground switch 925 to send any signal generated at the sensing element 911 to the ground 927, the sensing element 911 can be separated from the signal readout path (deactivation).

[0133] During the photo mode operation as described above, each sensing element 911 can be individually addressed to determine the size, shape and position of the beam spot on the surface of the detector 900. The photo mode switch 920 can be used to communicatively couple the sensing elements 911 to the output bus 902 during the photo mode operation. For example, to individually address Fig. 9A For each sensing element 911 in the portion 921 of the detector 900, the image pickup switch 942 can be closed to couple the output bus 902 to the analog signal path of the detector 900. With the image pickup switch 942 closed, each photo mode switch 920 can be closed and opened again in sequence to read the signal from each individual sensing element. When each photo mode switch 920 has been opened and closed to address its respective sensing element 911, the image pickup switch 942 can be opened to isolate the output bus 902 from the interconnect layer 916 and the portion of the circuit 903. Only the sensing element 914b without the photo mode switch 920 can be directly connected to the connection node 926 through the portion switch 943 when being addressed. This process can be performed simultaneously or continuously in other portions of the detector to generate an image of all beam spots on the detector surface.

[0134] In beam mode, some or all of the sensing elements 911 in section 921 may be combined together to form a common analog signal path. Figure 9A-9C In the comparative embodiment of FIG. 9 , this can be achieved by coupling each grouped sense element to a common output terminal 918 at sense element circuit 914 b. The grouped sense elements can be coupled together using upper element switch 915 u and right element switch 915 r to send the signal laterally through portion 921. Then, as Fig. 9A As shown, the common output terminal 918 can be coupled to the junction node 926 by enabling some switches 943.

[0135] This configuration may result in many sensing elements being connected in series. For example, sensing element circuit 914c is separated from sensing element 914b by two rows and two columns. Therefore, in order to couple sensing element 911 in sensing element circuit 914c to common output 918, at least two upper element switches 915u and two right element switches 915r in the lower level must be closed. If the sensing elements in the adjacent part are also grouped to the common output 918 of part 921, more inter-element switches must be closed. This series connection arrangement not only increases the parasitic parameters within the system, but also places structural requirements on inter-element switches 915. Since it is expected that any sensing element circuit may become part of this series connection, the switch must be made large enough to reduce its resistance to below an acceptable level. The increased size may produce additional parasitic parameters, such as parasitic capacitance.

[0136] The arrangement of this comparative embodiment also requires the addition of additional routing paths, switches, and other circuit components between the lower and upper levels, which may affect parasitic parameters and reduce bandwidth performance. Fig. 9C The comparative example is shown. Figure 9A-9B 900. A higher level (in the upper grey dashed box) may include interconnect switches, such as interconnect switch 930, for connecting adjacent parts to a common analog signal path. A lower level (in the lower grey dashed box) may include an inter-element switch 915 for connecting adjacent sensing elements to a common analog signal path. Between the two levels is an output bus 902 for coupling individual sensing elements 911 to the analog signal path via a photo mode switch 920 during photo mode. The output bus 902 and the photo pickup switch 942 can be viewed as intermediate components between the higher and lower levels, which, if eliminated, can reduce parasitic parameters and improve bandwidth performance. Switch arrangements that minimize parasitic parameters, such as by reducing the use of inter-element switches, can further improve bandwidth performance.

[0137] Figure 10A-10C FIG. 1 shows an improved switch matrix configuration of a detector 1000 consistent with an embodiment of the present disclosure. The detector 1000 may be Figure 2-Figure 8 Examples of detectors 244, 300A, 300B, 400, 500, 700, or 800 in FIG. Fig. 10A 1 , a 4x4 array of sense element circuits forms a portion 1021 of the detector 1000. Exemplary sense element circuit 1014a is shown in black, while other sense element circuits in portion 1021 are shown in gray. Interconnect layer 1016 is also shown in black. Sense element circuit 1014 (e.g., exemplary sense element circuit 1014a) may include sense element 1011 (e.g., a PIN diode), an inter-element switch 1015 for coupling to an adjacent sense element circuit, a ground switch and ground (labels omitted for clarity) for deactivating sense element 1011, and a pick-up switch 1042 for coupling to interconnect layer 1016.

[0138] Interconnect layer 1016 may also include interconnect switches 1030-1033 for coupling to adjacent sections, and for coupling section 1021 to signal processing circuits ( Fig. 10A The signal processing circuit may include, for example, Figure 4 The amplifier 404 or ADC 406 is shown. The readout switch 1012 can be similar to, for example Figure 4 Switch 412 or Figure 7 The readout switch 1012 may be located at an amplifier (eg Figure 4 Amplifier 404 or Figure 7In some embodiments, additional switches may be provided on the input side and the output side of the signal processing circuit. In some embodiments of the present disclosure, the readout switch 1012 may not be provided in each section. For example, as described above with respect to Figure 7 As discussed, for each 2x2 array portion in the detector 1000, there may be a signal processing circuit (e.g. Figure 7 The portion without dedicated signal processing circuitry can route its detection signal to the portion with dedicated signal processing circuitry.

[0139] Fig. 10A The arrangement can provide Figure 9A-9C The improvements can be achieved in a variety of different operating modes, such as photo mode and beam mode.

[0140] For example, in Figure 9A-9C , during photo mode, sensing element 911 is connected to intermediate output bus 902 and then coupled to interconnect layer 916 via a single photo mode pickoff switch 942. In contrast, element 1011 may be coupled directly to interconnect layer 1016 via a dedicated pickoff switch 1042 without the need for an intermediate output bus or photo mode switch. During photo mode operation, each sensing element 1011 may be individually addressed by switching its corresponding pickoff switch 1042 on and off to connect the sensing element to interconnect layer 1016. If sensing element 1011 is located within a portion having a readout switch 1012 (e.g., portion 1021), the signal may be routed to a signal processing circuit by enabling readout switch 1012. Alternatively, the signal may be routed to a signal processing circuit in a nearby portion by enabling an appropriate interconnect switch (e.g., switches 1030-1033). Thus, given that Fig. 10A A simplified architecture is shown in Figure 2, which enables photo mode operation with improved parasitic parameters.

[0141] In beam mode, signal processing speed is very important. Fig. 10A The improved architecture allows the selection of the optimal switch configuration to maximize bandwidth performance. For example, since each sense element circuit 1014 can be directly coupled to a portion node 1029 of the interconnect layer 1016 within its own portion, the need for lateral switching at the inter-element switch 1015 is reduced. In the portion 1021, the inter-element switch 1015 can be employed, for example, only when its respective sense element 1011 must be routed to a signal processing circuit other than the circuit to which its own interconnect layer unit is coupled.

[0142] For example, if a portion of node 1029 of interconnect layer 1016 within portion 1021 is coupled to processing circuitry via readout switch 1012, but a sense element 1011 within sense element circuit 1014a is grouped with adjacent sense elements in a different portion to the left (not shown), the sense element may be coupled to the adjacent sense element via inter-element switch 1015. However, if sense element 1011 within sense element circuit 1014a is grouped with sense elements coupled to readout switch 1012 via interconnect layer 1016, it may be coupled via pick-up switch 1042. In general, when a sense element 1011 in beam mode is grouped in the same analog signal path as a portion of node 1029 at a higher level within its own portion, it may be coupled via pick-up switch 1042. Pick-up switches 1042 are generally preferred because they allow more parallel connections than inter-element switches 1015. However, the switch configuration selected may ultimately depend on the optimization of the total parasitic parameters in the system, rather than the default selection available for pick-up switch 1042. In other words, in some cases, even if the pick-off switch 1042 coupling is available, it may be preferred to use the inter-element switch 1015.

[0143] Fig. 10B The embodiment consistent with the present disclosure is shown Fig. 10A A hierarchical view of the detector 1000. The higher levels (in the upper gray dashed box) may include interconnect switches, such as interconnect switch 1030, for connecting adjacent parts to a common analog signal path. The lower levels (in the lower gray dashed box) may include inter-element switches 1015 for connecting adjacent sensing elements to a common analog signal path. Fig. 9C Unlike the higher level, there may be no intermediate output bus between the lower level. Fig. 9C The sensing element circuit 914b in is different, Fig. 10B All sensing element circuits in the may be substantially identical (e.g., comparing Fig. 9C Different sensing element circuits 914a / b and Fig. 10B This is possible because there may not be a need to provide a separate common output, e.g. Figure 9A-9B 918 in the beam mode. During beam mode, any sensing element grouped in a common analog signal path with its own portion of a higher level can be coupled to the higher level directly at the portion node 1029 or through its respective pick-off switch 1042. Inter-element switches 1015 in the lower level can be used to couple sensing elements to adjacent analog signal paths.

[0144] Fig. 10C A partial array of 2x2 sensing elements of detector 1000 is shown, including Fig. 10APart 1021. is consistent with the embodiments of the present disclosure. Fig. 10C 1021 to the signal processing circuitry. However, more or fewer portions may include readout switches 1012. As described above, interconnect layer 1016 (shown in black) may form repeating units in higher levels of the switch matrix of detector 1000. For example, portion 1021 may include interconnect switch 1030 for coupling portion 1021 to another portion of sensing elements above it in the plane of detector 1000 (not shown), while interconnect switch 1031 may form a right switch for coupling portion 1021 to another portion of sensing elements to the right of the plane (also not shown). Similarly, interconnect switch 1033 may form a right switch for a portion to the left of portion 1021, while interconnect switch 1032 may form a top switch for a portion below portion 1021 in the plane of detector 1000. A sensing element may be coupled to a portion node 1029 of a higher level by enabling its associated pick-up switch 1042, and may be further coupled to other nodes of a higher level by enabling interconnect switches (e.g., 1030-1033). In some embodiments, higher levels may include other interconnect switches, such as diagonal interconnect switches.

[0145] The sensing elements can also be coupled to each other by enabling the inter-element switches 1015 in the lower hierarchy levels. For example, the two sensing elements in the upper left corner of the section 1021 can be coupled to each other by enabling the inter-element switch 1015a between them. These sensing elements can be further coupled to the next sensing element on the left (in the adjacent section) by enabling the inter-element switch 1015b. Thus, the sensing element group can form inter-section and intra-section coupling without using higher hierarchy levels. However, at least one higher hierarchy level connection must be present to read out the signal in the signal processing circuit.

[0146] Fig.11 is a diagram showing different switch configurations on a portion of a detector surface 1100. The detector 1100 may be Figure 2-Figure 8 or Figure 10A-10C 100. The illustrated portion of the surface of detector 1100 includes sixteen sections arranged in rows AD and columns 1-4, each section including a 4x4 array of sensing elements. Within each section, the individual sensing elements can be identified by numbers according to the labels shown in section A1. For clarity, the sections are shown in alternating dark / light colors. Within each dark / light section, each sensing element can be coupled to a common section node via its respective pick-up switch, such as Figure 10A-10C As described above, some embodiments may provide a readout switch (e.g. Figure 10A-10CThe readout switch 1012) and signal processing circuit are provided, while other embodiments may not provide them. Fig.11 In the embodiment of the present invention, each 2x2 partial array may include a portion having a readout switch leading to a signal processing circuit. For example, as shown by the black dots, portions A2, A4, C2, and C4 may each provide a readout switch 1112 coupled to a channel of the signal processing circuit. The remaining portions may couple their sensing elements to the signal processing circuit of another portion through the hierarchical switch matrix of the present disclosure.

[0147] Two secondary beam spots S1 and S2 are incident on the illustrated portion of the detector 1100. For example, the size, shape, and position of the spots S1 and S2 can be determined during photo mode operation. Sensing elements determined to fall within the boundaries of each spot can be grouped with each other to detect the beam spot intensity during beam mode operation (e.g., SEM inspection process).

[0148] The size and position of the spots S1 and S2 and the size and number of the segments and sensing elements are for illustration purposes only. In some embodiments, the secondary beam spots S1, S2 may be larger or smaller in proportion to the sensing elements and segments of the detector 1100. For example, the beam spot may not cover the entire segment, or may not cover an area containing the readout switch 1012 (e.g., Fig. 10A -C in 1012). The beam spots can be spaced closer or farther apart, and their sizes and shapes can be different from each other. There can be more or less than two beam spots S1, S2 on the surface of the detector 1100. Fig.11 The illustrative arrangement of allows for discussion of some switch configurations that may be used in embodiments of the present disclosure.

[0149] With respect to spot S1, the four parts (A3A4, B3, B4) can be switched by activating their respective pick switches (e.g. Figure 10A-10C 1042 in FIG. 1044 ) couples each sensing element to a respective higher-level layer in a common analog signal path. However, of the four sections, only A4 may include a readout switch. Thus, sections A3, B3, and B4 may be laterally coupled at a higher-level layer (e.g., via Figure 10A-10C 1030-1033) to a portion including a readout switch. For example, portions A3, B3, and B4 may be coupled to A2, A4, or C4 via lateral interconnection switches in a higher-level layer. For reasons discussed below, portion C2 may not be coupled to beam spot S1 of a higher-level layer even if a readout switch is provided.

[0150] Similarly, the sensing elements in region A2 may be coupled to higher levels via their pick-up switches. However, not every sensing element in region A1 receives a portion of point S1. For example, sensing element 1 in region A2 (i.e., sensing element A2-1) may be deactivated by disabling its pick-up switch (and any inter-element switches) to reduce parasitics in the system. Sensing element A2-1 may be further grounded (e.g., via Fig. 10B The ground switch 1025 shown is used to prevent charge accumulation. In addition, in some embodiments, it can be determined that the sensing element A2-5 does not receive enough points S1 to warrant connecting it to the system. Therefore, in some embodiments, the sensing element A2-5 can be similarly disabled.

[0151] In the B2 section, all sensing elements except B2-9 and B2-13 can be coupled to a higher level through a pick-off switch and then routed to, for example, the A2 section for readout through a single interconnect switch. Sensing elements B2-9 and B2-13 can be deactivated by disabling their pick-off switches.

[0152] Section C2 presents a different situation because it receives parts of points S1 and S2. Here, the higher-level layers within section C2 should be grouped only to one point or the other. Therefore, a decision must be made as to which point will utilize the higher-level layers of section C2 and which point will have inter-element switches (e.g. Figure 10A-10B 1015). Since more sensing elements of portion C2 are assigned to point S2, it may be decided to assign a higher-level layer of portion C2 to point S2. Additionally, portions C1, D1, and D2 may utilize a higher-level layer to couple their sensing elements to the readout switch of portion C2 (although it should be understood that there may be other readout switches available in other portions outside of the area shown). Finally, sensing elements C2-3, C2-4, and C2-8 may be grouped with point S1 using inter-element switches in lower-level layers. For example, sensing element C2-4 may be coupled to sensing element B2-16 by enabling an inter-element switch between them.

[0153] It is worth noting that in Fig.11 Of all the sensing elements shown, only three (C2-3, C2-4, and C2-8) may be coupled by a lower level switch. The exemplary switch configuration discussed above allows nearly every sensing element to be "vertically" coupled to a higher level via a parallel pickup switch. By reducing the use of lateral inter-element switches, the number of series connections can be reduced. In addition, since the inter-element switches can be designed to support smaller currents given the preferred switch configuration, the inter-element switches can be made smaller to further reduce parasitic parameters.

[0154] In some embodiments, even if a higher level switch is available, the sensing element can still be coupled to its group through a lower level switch. Fig.11 , sense elements D3-9 and D3-13 may be coupled via inter-element switches, even though they may be coupled in another manner, such as using a pick-off switch to couple to a higher level and an interconnect switch to couple to portion D1. As discussed above, in some cases, bandwidth performance may be optimized by using lower level inter-element switches.

[0155] Fig.12 An exemplary method 1200 for setting a switch configuration of a beam spot on a detector according to an embodiment of the present disclosure is shown. The detector may be, for example, Figure 2-Figure 8 or Figure 10A-Figure 11 The method may be performed by a controller (e.g. Figure 1 The controller 109 or Figure 8 Controller 804 in executes.

[0156] In step 1201, the controller may obtain array information about the size, shape, and position of the beam spot. The array information may alternatively or additionally include information about the grouping of each sensing element on the detector surface. For example, the grouping information may include information about which sensing elements are assigned to which beam spot and which sensing elements should be deactivated. Since each sensing element will be assigned to at most one beam spot, this information also determines which sensing elements can be grouped with each other. The grouping of sensing elements can typically be continuous. However, in some embodiments, non-contiguous groups of sensing elements can be assigned to beam spots. The array information can be determined by, for example, a photo mode operation.

[0157] In step 1202, the controller may use the array information to select the appropriate sensing element portion corresponding to each beam spot and determine the appropriate path from each beam spot to the readout switch. For example, the controller may select the available readout switch closest to the centroid (or geometric center) of the beam spot. The controller may then determine the path from the centroid of the beam spot to the readout switch along a higher level. In some embodiments, the nearest available readout switch may be located in the same portion as the centroid of the beam spot. In some embodiments, the nearest available readout switch may be located in a different portion. When the nearest available readout switch is located in a diagonal portion, the path may include interconnecting switches through an intermediate portion in a horizontal or vertical direction. In some embodiments, a higher level may include a diagonal connection.

[0158] At step 1203, the higher levels of the remaining parts are assigned to the most suitable beam spots. Fig.11, part A3 can be allocated to beam spot S1. Part A1 can be unallocated. Part C2 is receiving electrons from two beam spots S1 and S2. Since beam spot S2 is incident on more sensing elements than beam spot S1, it can be considered that beam spot S2 is the most suitable beam spot.

[0159] In some embodiments, there may be a threshold count of sensing elements below which no sensing element may allocate any beam spot to a higher level of the part. Fig.11 If there are fewer than, for example, four sensing elements in section C2 that receive any single beam spot, then the higher levels within section C2 can be left unassigned (i.e., by opening all interconnect switches bordering section C2). In this case, the sensing elements in section C2 can be grouped by closing the inter-element switches in the lower levels. The threshold value can be calculated based on measurements of parasitic parameters in the system. For example, it can be determined that the contribution to the parasitic parameters from the inter-element switches of only three sensing elements may be less than the contribution to the parasitic parameters of the higher level sections. The threshold number can be weighted based on, for example, series connections. For example, three sensing elements connected in parallel to adjacent sections (e.g., connecting sensing elements D3-5, 9, and 13 to Fig.11 The portion D2 in FIG. 1 may contribute fewer parasitic parameters than three sense elements connected in series (eg, connecting sense elements C2-5, 9, and 13 to portion D2).

[0160] At step 1204, the controller may set the lower level switches. This may include, for example, determining the appropriate open or closed state of each switch and activating it accordingly. Alternatively, the process may be performed in stages.

[0161] In the first stage, the lower levels can be set up assuming that no higher levels exist. For example, in each sensing element circuit, when the sensing elements on the right are assigned to the same beam spot, the controller can close the right inter-element switch. Similarly, when the sensing elements above are assigned to the same beam spot, the controller can close the top inter-element switch.

[0162] In the second stage, any closed inter-element switches that are deemed unnecessary can be opened. For example, when a first sensing element and a second sensing element to the right of the first sensing element are both assigned to the same higher-level path, the inter-element switch between them can be opened. For sensing elements arranged in a vertical (upward) direction in the detector plane, a corresponding process can be performed.

[0163] In step 1205, the controller may set higher level switches based on the higher level assignments in steps 1202-1203. For example, in each section, when the sections to the right are assigned to the same beam spot, the controller may close the right interconnection switch. Similarly, when the sections above it are assigned to the same beam spot, the controller may close the top interconnection switch. In some embodiments, redundant higher level switches may be eliminated. For example, if the sections of a 2x2 array are all assigned to the same beam spot, e.g. Fig.11 In some embodiments, if the interconnection switches in the 2x2 array are sections A3, A4, B3, B4, then section B3 may have multiple higher-level paths to the readout switches in section A4. In some embodiments, all interconnection switches in this 2x2 array may be turned off. In some embodiments, less than all interconnection switches may be turned off.

[0164] At step 1206, the controller may set the pick-up switch and the ground switch to activate or deactivate the sensing element. For example, for each sensing element assigned to the same beam spot as the interconnect layer unit within its portion, its associated pick-up switch may be closed to couple the sensing element to a higher level. At the same time, the ground switch associated with the sensing element may be opened. Thus, the sensing element may be activated. At step 1204, other sensing elements may be activated by the element switch between the lower level elements. For these sensing elements, their pick-up switches and ground switches may be opened.

[0165] Any unassigned sensing element may be deactivated. Deactivation may include, for example, opening a switch coupling the sensing element to the system, e.g. Figure 10A-10C Pickup switch 1042 or inter-element switch 1015 shown. An entire section can be disabled by opening any interconnecting switches bordering the section.

[0166] The switch configuration can be selected to optimize the bandwidth performance in the detector to increase the signal processing speed. For example, the bandwidth performance can be optimized by minimizing parasitic parameters.

[0167] It should be understood that the above process is one of many possible methods to implement the switch arrangement. The steps may be performed in a different order than described, or a completely different set of steps may be employed. For example, the switching method may include closing only those switches that are needed from the outset, rather than closing a set of lower-level switches and subsequently opening any unneeded switches. In general, static configuration of the switch matrix can be achieved through a variety of switching algorithms.

[0168] Embodiments of the present disclosure may be further described by the following clauses:

[0169] 1. A method for configuring a switch matrix in a charged particle detector, comprising:

[0170] disabling a first inter-element switch between a first sensing element and a second sensing element of the charged particle detector to prevent charge from flowing between the first sensing element and the second sensing element via the first inter-element switch, the first inter-element switch forming part of a lower level of the switch matrix;

[0171] enabling a first pick-off switch between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level via the first pick-off switch; and

[0172] enabling a second pick-off switch between the second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level through the second pick-off switch;

[0173] Wherein the first sensing element and the second sensing element are coupled to a common analog signal path of the higher-level detector.

[0174] 2. A method according to clause 1, wherein:

[0175] The charged particle detector includes a plurality of sensing elements, including the first sensing element and the second sensing element;

[0176] The plurality of sensing elements are divided into a plurality of sensing elements by interconnection switches between the sensing elements; and

[0177] Each interconnect switch of the plurality of interconnect switches forms part of the higher level.

[0178] 3. A method according to clause 2, wherein:

[0179] the first sensing element forms part of a first portion of the plurality of portions; and

[0180] the second sensing element forming part of a second portion of the plurality of portions;

[0181] The method further comprises:

[0182] A first interconnect switch between the first portion and the second portion is enabled to couple the first sensing element and the second sensing element to a common analog signal path of a detector at the higher level.

[0183] 4. A method according to clause 3, wherein:

[0184] The higher level includes a readout switch coupled to a signal processing circuit of the charged particle detector.

[0185] 5. A method according to clause 4, wherein:

[0186] the first interconnect switch being located between the first pick-off switch and the read-out switch on the common analog signal path;

[0187] The first interconnect switch is not located between the second pick-off switch and the readout switch on the common analog signal path.

[0188] 6. A method according to clause 2, wherein:

[0189] The first sensing element and the second sensing element form part of a first portion of the plurality of portions;

[0190] The first sensing element is coupled to a common analog signal path of the detector at a first node of the higher level through the first pick-off switch; and

[0191] The second sensing element is coupled to a common analog signal path of the detector at the higher-level first node through the second pick-off switch.

[0192] 7. The method according to clause 6, further comprising:

[0193] enabling a second inter-element switch between the second sensing element and a third sensing element of the charged particle detector to allow charge to flow between the third sensing element and the second sensing element via the second inter-element switch, the second inter-element switch forming part of the lower level; wherein:

[0194] The third sensing element forms a part of a second part of the plurality of parts.

[0195] 8. The method according to clause 7, further comprising:

[0196] A third pick-up switch between the third sensing element and a second node of the higher level is disabled to prevent charge from flowing between the third sensing element and the second node via the third pick-up switch.

[0197] 9. The method according to clause 6, further comprising:

[0198] disabling a third pick-up switch between the third sensing element and the first node to prevent charge from flowing between the third sensing element and the first node via the third pick-up switch;

[0199] enabling a ground switch between the third sensing element and a ground connection to prevent charge accumulation at the third sensing element,

[0200] The third sensing element forms a part of a first part among the plurality of parts.

[0201] 10. The method of clause 1, wherein the first sensing element and the second sensing element comprise PIN diodes.

[0202] 11. The method of clause 1, wherein the charged particle detector is part of a charged particle beam system.

[0203] 12. The method of clause 11, wherein the charged particle beam system is a SEM inspection tool.

[0204] 13. The method according to clause 1, further comprising:

[0205] determining a size, shape or position of a beam spot on a surface of the charged particle detector;

[0206] assigning the first sensing element and the second sensing element to the common analog signal path based on the determined size, shape, or position of the beam spot; and

[0207] selecting a switch configuration based on the assignment;

[0208] Wherein the switch configuration includes the first inter-element switch being disabled, the first pick-up switch being enabled, and the second pick-up switch being enabled.

[0209] 14. The method of clause 13, wherein the switch configuration is selected based on parasitic parameters of the switch configuration.

[0210] 15. A non-transitory computer readable medium storing a set of instructions executable by at least one processor of a device to cause the device to perform a method comprising:

[0211] disabling a first inter-element switch between a first sensing element and a second sensing element of the charged particle detector to prevent charge from flowing between the first sensing element and the second sensing element via the first inter-element switch, the first inter-element switch forming part of a lower level of the switch matrix;

[0212] enabling a first pick-off switch between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level via the first pick-off switch; and

[0213] enabling a second pick-off switch between the second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level through the second pick-off switch;

[0214] Wherein the first sensing element and the second sensing element are coupled to a common analog signal path of the higher-level detector.

[0215] 16. The non-transitory computer-readable medium of clause 15, wherein:

[0216] The charged particle detector includes a plurality of sensing elements, including the first sensing element and the second sensing element;

[0217] The plurality of sensing elements are divided into a plurality of sensing elements by interconnection switches between the sensing elements; and

[0218] Each interconnect switch of the plurality of interconnect switches forms part of the higher level.

[0219] 17. The non-transitory computer-readable medium of clause 16, wherein:

[0220] the first sensing element forms part of a first portion of the plurality of portions; and

[0221] the second sensing element forming part of a second portion of the plurality of portions;

[0222] The instruction set executable by at least one processor of the device causes the device to further perform:

[0223] A first interconnect switch between the first portion and the second portion is enabled to couple the first sensing element and the second sensing element to a common analog signal path of the higher-level detector.

[0224] 18. The non-transitory computer-readable medium of clause 17, wherein:

[0225] The higher level includes a readout switch coupled to a signal processing circuit of the charged particle detector.

[0226] 19. The non-transitory computer-readable medium of clause 18, wherein:

[0227] the first interconnect switch being located between the first pick-off switch and the read-out switch on the common analog signal path; and

[0228] The first interconnect switch is not located between the second pick-off switch and the readout switch on the common analog signal path.

[0229] 20. The non-transitory computer-readable medium of clause 16, wherein:

[0230] The first sensing element and the second sensing element form part of a first portion of the plurality of portions;

[0231] The first sensing element is coupled to a common analog signal path of the detector at a first node of the higher level through the first pick-off switch; and

[0232] The second sensing element is coupled to a common analog signal path of the detector at the first node through the second pick-off switch.

[0233] 21. The non-transitory computer-readable medium of clause 20, wherein the set of instructions executable by at least one processor of the apparatus causes the apparatus to further perform:

[0234] enabling a second inter-element switch between the second sensing element and a third sensing element of the charged particle detector to allow charge to flow between the third sensing element and the second sensing element via the second inter-element switch, the second inter-element switch forming part of the lower level; wherein:

[0235] The third sensing element forms a part of a second part of the plurality of parts.

[0236] 22. The non-transitory computer-readable medium of clause 21, wherein the set of instructions executable by at least one processor of the device causes the device to further perform:

[0237] A third pick-up switch between the third sensing element and a second node of the higher level is disabled to prevent charge from flowing between the third sensing element and the second node via the third pick-up switch.

[0238] 23. The non-transitory computer-readable medium of clause 20, wherein the set of instructions executable by at least one processor of the device causes the device to further perform:

[0239] disabling a third pick-up switch between the third sensing element and the first node to prevent charge from flowing between the third sensing element and the first node via the third pick-up switch; and

[0240] enabling a ground switch between the third sensing element and a ground connection to prevent charge accumulation at the third sensing element,

[0241] The third sensing element forms a part of a first part among the plurality of parts.

[0242] 24. The non-transitory computer-readable medium of clause 15, wherein the first sensing element and the second sensing element comprise PIN diodes.

[0243] 25. The non-transitory computer-readable medium of clause 15, wherein the charged particle detector is part of a charged particle beam system.

[0244] 26. The non-transitory computer readable medium of clause 25, wherein the charged particle beam system is a SEM inspection tool.

[0245] 27. The non-transitory computer-readable medium of clause 15, wherein the set of instructions executable by at least one processor of the apparatus causes the apparatus to further perform:

[0246] determining a size, shape or position of a beam spot on a surface of the charged particle detector;

[0247] assigning the first sensing element and the second sensing element to the common analog signal path according to the determined size, shape or position of the beam spot; and

[0248] selecting a switch configuration according to the assignment;

[0249] Wherein the switch configuration includes the first inter-element switch being disabled, the first pick-up switch being enabled, and the second pick-up switch being enabled.

[0250] 28. The non-transitory computer-readable medium of clause 27, wherein the switch configuration is selected based on parasitic parameters of the switch configuration.

[0251] 29. A charged particle beam device comprising:

[0252] a charged particle beam source configured to generate a primary charged particle beam;

[0253] a charged particle optical system configured to direct the primary charged particle beam to a sample surface to inspect the sample surface;

[0254] a charged particle detector configured to detect charged particles returning from the sample surface, wherein the charged particle detector comprises a first sensing element and a second sensing element; and

[0255] A controller includes one or more processors and is configured to cause the charged particle beam device to perform the following method:

[0256] disabling a first inter-element switch between the first sensing element and the second sensing element to prevent charge from flowing between the first sensing element and the second sensing element via the first inter-element switch, the first inter-element switch forming part of a lower level of the switch matrix;

[0257] enabling a first pick-off switch between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level via the first pick-off switch; and

[0258] enabling a second pick-off switch between the second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level through the second pick-off switch;

[0259] Therein, the first sensing element and the second sensing element are coupled to a common analog signal path of the detector at the higher level.

[0260] 30. A charged particle beam apparatus according to clause 29, wherein:

[0261] The charged particle detector comprising a plurality of sensing elements comprises the first sensing element and the second sensing element;

[0262] The plurality of sensing elements are divided into a plurality of partial sensing elements by interconnecting switches between the portions of the sensing elements; and

[0263] Each interconnect switch of the plurality of interconnect switches forms part of the higher level.

[0264] 31. A charged particle beam apparatus according to clause 30, wherein:

[0265] the first sensing element forming part of a first portion of the plurality of portions;

[0266] the second sensing element forms part of a second portion of the plurality of portions; and

[0267] The first sensing element and the second sensing element are coupled to a common analog signal path of the higher-level detector by enabling a first interconnect switch between the first portion and the second portion.

[0268] 32. A charged particle beam apparatus according to clause 31, wherein:

[0269] The higher level includes a readout switch coupled to a signal processing circuit of the charged particle detector.

[0270] 33. A charged particle beam apparatus according to clause 32, wherein:

[0271] the first interconnect switch being located between the first pick-off switch and the read-out switch on the common analog signal path;

[0272] The first interconnect switch is not located between the second pick-off switch and the readout switch on the common analog signal path.

[0273] 34. A charged particle beam apparatus according to clause 30, wherein:

[0274] The first sensing element and the second sensing element form part of a first portion of the plurality of portions;

[0275] The first sensing element is coupled to a common analog signal path of the detector at a first node of the higher level through the first pick-off switch; and

[0276] The second sensing element is coupled to a common analog signal path of the detector at the higher-level first node through the second pick-off switch.

[0277] 35. A charged particle beam apparatus according to clause 34, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0278] enabling a second inter-element switch between the second sensing element and the third sensing element of the charged particle detector to allow charge to flow between the third sensing element and the second sensing element via the second inter-element switch, the second inter-element switch forming part of the lower level; wherein:

[0279] The third sensing element forms a part of a second part of the plurality of parts.

[0280] 36. A charged particle beam apparatus according to clause 35, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0281] A third pick-up switch between the third sensing element and a second node of the higher level is disabled to prevent charge from flowing between the third sensing element and the second node via the third pick-up switch.

[0282] 37. A charged particle beam apparatus according to clause 29, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0283] disabling a third pick-up switch between the third sensing element and the first node to prevent charge from flowing between the third sensing element and the first node via the third pick-up switch; and

[0284] enabling a ground switch between the third sensing element and a ground connection to prevent charge accumulation at the third sensing element,

[0285] The third sensing element forms a part of a first part among the plurality of parts.

[0286] 38. A charged particle beam apparatus according to clause 29, wherein the first sensing element and the second sensing element comprise PIN diodes.

[0287] 39. The charged particle beam apparatus of clause 29, wherein the charged particle detector is part of the charged particle beam system.

[0288] 40. The charged particle beam apparatus of clause 39, wherein the charged particle beam system is a SEM inspection tool.

[0289] 41. The charged particle beam apparatus according to clause 29, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0290] determining a size, shape or position of a beam spot on a surface of the charged particle detector;

[0291] assigning the first sensing element and the second sensing element to the common analog signal path according to the determined size, shape or position of the beam spot; and

[0292] selecting a switch configuration according to the assignment;

[0293] Wherein the switch configuration includes the first inter-element switch being disabled, the first pick-up switch being enabled, and the second pick-up switch being enabled.

[0294] 42. A charged particle beam apparatus according to clause 41, wherein the switch configuration is selected based on parasitic parameters of the switch configuration.

[0295] 43. A method of configuring a switch matrix in a charged particle detector, comprising:

[0296] enabling a first pick-up switch between a first sensing element and a first node of a higher level of the switch matrix to allow charge to flow between the first sensing element and the first node via the first pick-up switch, the first sensing element receiving the charged particles of the first beam spot;

[0297] activating a first inter-element switch between a second sensing element and a third sensing element to allow charge to flow between the second sensing element and the third sensing element through the first inter-element switch, the second sensing element and the third sensing element receiving the charged particles of the second beam spot;

[0298] disabling a second pick-up switch between the second sensing element and the first node to prevent charge from flowing between the second sensing element and the first node via the pick-up switch; and

[0299] A third pick-off switch between the third sensing element and a second node of a higher level of the switch matrix is ​​enabled to allow charge to flow between the third sensing element and the second node via the third pick-off switch.

[0300] 44. A method according to clause 43, wherein

[0301] The first node is a common node of the higher level in a first portion of sensing elements, the first portion including the first sensing element and the second sensing element; and

[0302] The second node is a common node of the higher level in a second portion of sensing elements, the second portion including the third sensing element.

[0303] 45. The method according to clause 44, further comprising:

[0304] The first interconnection switch between the first node and the second node is disabled to prevent charge from flowing in the higher level between the first node and the second node through the first interconnection switch.

[0305] 46. ​​The method according to clause 43, further comprising:

[0306] disabling the second inter-element switch between a fourth sensing element and at least one of the first sensing element and the second sensing element to prevent charge from flowing between the fourth sensing element and at least one of the first sensing element and the second sensing element; and

[0307] A fourth pick-up switch between the fourth sensing element and the first node is disabled to prevent charge from flowing between the fourth sensing element and the first node via the fourth pick-up switch.

[0308] 47. The method according to clause 43, further comprising:

[0309] enabling a first readout switch between the higher level and the first signal processing circuit to allow the first signal to reach the first signal processing circuit, the first signal being representative of at least the charge from the first sensing element; and

[0310] A second readout switch between the higher level and the second signal processing circuit is enabled to allow the second signal to reach the second signal processing circuit, the second signal being representative of at least the charge from the second sensing element.

[0311] 48. The method of clause 47, wherein one of the first signal processing circuit and the second signal processing circuit comprises an analog-to-digital converter (ADC).

[0312] 49. The method according to clause 47, further comprising:

[0313] determining a first characteristic of the first beam spot according to the first signal; and

[0314] A second characteristic of the second beam spot is determined based on the second signal.

[0315] 50. A method according to clause 49, wherein:

[0316] The first characteristic comprises an intensity of the first beam spot; and

[0317] The second characteristic includes an intensity of the second beam spot.

[0318] 51. A non-transitory computer readable medium storing a set of instructions executable by at least one processor of a device to cause the device to perform a method comprising:

[0319] enabling a first pick-off switch between a first sensing element and a first node of a higher level of the switch matrix to allow charge to flow between the first sensing element and the first node via the first pick-off switch, the first sensing element being configured to receive charged particles of the first beam spot;

[0320] enabling a first inter-element switch between a second sensing element and a third sensing element to allow charge to flow between the second sensing element and the third sensing element through the first inter-element switch, the second sensing element and the third sensing element being configured to receive charged particles of a second beam spot;

[0321] disabling a second pick-up switch between the second sensing element and the first node to prevent charge from flowing between the second sensing element and the first node via the pick-up switch; and

[0322] A third pick-off switch between a third sensing element and a second node of a higher level of the switch matrix is ​​enabled to allow charge to flow between the third sensing element and the second node via the third pick-off switch.

[0323] 52. The non-transitory computer readable medium of clause 51, wherein

[0324] The first node is a common node of the higher level in a first portion of sensing elements, the first portion including the first sensing element and the second sensing element; and

[0325] The second node is a common node of the higher level in the second portion of sensing elements, and the second portion includes the third sensing element.

[0326] 53. The non-transitory computer-readable medium of clause 52, wherein the set of instructions executable by the at least one processor of the device causes the device to further perform:

[0327] A first interconnection switch between the first node and the second node is disabled to prevent charge from flowing in the higher level between the first node and the second node through the first interconnection switch.

[0328] 54. The non-transitory computer-readable medium of clause 51, wherein the set of instructions executable by at least one processor of the apparatus causes the apparatus to further perform:

[0329] disabling a second inter-element switch between a fourth sensing element and at least one of the first sensing element and the second sensing element to prevent charge from flowing between the fourth sensing element and at least one of the first sensing element and the second sensing element; and

[0330] A fourth pickup switch between the fourth sensing element and the first node is disabled to prevent charge from flowing between the fourth sensing element and the first node via the fourth pickup switch.

[0331] 55. The non-transitory computer-readable medium of clause 51, wherein the set of instructions executable by at least one processor of the apparatus causes the apparatus to further perform:

[0332] enabling a first readout switch between the higher level and the first signal processing circuit to allow a first signal to reach the first signal processing circuit, the first signal being representative of at least a charge from the first sensing element; and

[0333] A second readout switch between the higher level and a second signal processing circuit is enabled to allow a second signal to reach the second signal processing circuit, the second signal being representative of at least the charge from the second sensing element.

[0334] 56. The non-transitory computer-readable medium of clause 55, wherein one of the first signal processing circuit and the second signal processing circuit comprises an analog-to-digital converter (ADC).

[0335] 57. The non-transitory computer-readable medium of clause 55, wherein the set of instructions executable by at least one processor of the apparatus causes the apparatus to further perform:

[0336] determining a first characteristic of the first beam spot based on the first signal; and

[0337] A second characteristic of the second beam spot is determined based on the second signal.

[0338] 58. The non-transitory computer-readable medium of clause 57, wherein:

[0339] The first characteristic comprises an intensity of the first beam spot; and

[0340] The second characteristic includes an intensity of the second beam spot.

[0341] 59. A charged particle beam device comprising:

[0342] a charged particle beam source configured to generate a primary charged particle beam;

[0343] a charged particle optical system configured to direct the primary charged particle beam to a sample surface to inspect the sample surface;

[0344] a charged particle detector configured to detect charged particles returning from the sample surface; and

[0345] A controller includes one or more processors and is configured to cause the charged particle beam device to perform the following method:

[0346] enabling a first pick-off switch between a first sensing element and a first node of a higher level of the switch matrix to allow charge to flow between the first sensing element and the first node via the first pick-off switch, the first sensing element being configured to receive charged particles of the first beam spot;

[0347] enabling a first inter-element switch between a second sensing element and a third sensing element to allow charge to flow between the second sensing element and the third sensing element through the first inter-element switch, the second sensing element and the third sensing element being configured to receive charged particles of a second beam spot;

[0348] disabling a second pick-up switch between the second sensing element and the first node to prevent charge from flowing between the second sensing element and the first node via the pick-up switch; and

[0349] A third pick-off switch between a third sensing element and a second node of a higher level of the switch matrix is ​​enabled to allow charge to flow between the third sensing element and the second node via the third pick-off switch.

[0350] 60. The charged particle beam apparatus of clause 59, wherein:

[0351] The first node is a common node of the higher level in a first portion of sensing elements, the first portion including the first sensing element and the second sensing element; and

[0352] The second node is a common node of the higher level in a second portion of sensing elements, the second portion including the third sensing element.

[0353] 61. The charged particle beam apparatus according to clause 60, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0354] The first interconnection switch between the first node and the second node is disabled to prevent charge from flowing in the higher level between the first node and the second node through the first interconnection switch.

[0355] 62. The charged particle beam apparatus according to clause 59, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0356] disabling a second inter-element switch between a fourth sensing element and at least one of the first sensing element and the second sensing element to prevent charge from flowing between the fourth sensing element and at least one of the first sensing element and the second sensing element; and

[0357] The fourth pick-up switch between the fourth sensing element and the first node is disabled to prevent charge from flowing between the fourth sensing element and the first node via the fourth pick-up switch.

[0358] 63. The charged particle beam apparatus according to clause 59, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0359] enabling a first readout switch between the higher level and a first signal processing circuit to allow a first signal to reach the first signal processing circuit, the first signal being representative of at least a charge from the first sensing element; and

[0360] A second readout switch between the higher level and the second signal processing circuit is enabled to allow a second signal to reach the second signal processing circuit, the second signal being representative of at least the charge from the second sensing element.

[0361] 64. The charged particle beam apparatus of clause 63, wherein one of the first signal processing circuit and the second signal processing circuit comprises an analog / digital converter (ADC).

[0362] 65. The charged particle beam apparatus according to clause 63, wherein the controller is further configured to cause the charged particle beam apparatus to perform:

[0363] determining a first characteristic of the first beam spot based on the first signal; and

[0364] A second characteristic of the second beam spot is determined based on the second signal.

[0365] 66. The charged particle beam apparatus of clause 65, wherein:

[0366] The first characteristic comprises an intensity of the first beam spot; and

[0367] The second characteristic includes an intensity of the second beam spot.

[0368] 67. A charged particle detector having a switch matrix comprising a higher level and a lower level, the charged particle detector comprising:

[0369] A plurality of sections, each section comprising a plurality of sensing element circuits arranged in an array, each sensing element circuit comprising:

[0370] a sensing element configured to generate charge from a charged particle landing event at the sensing element;

[0371] a pick-off switch configured to couple the sensing element to a higher level node of the switch matrix in the section; and

[0372] an inter-element switch configured to couple the sensing element to an adjacent sensing element to allow charge to flow between the sensing element and the adjacent sensing element, the inter-element switch forming part of the lower level;

[0373] Wherein, within each of the plurality of sections, each sensing element is configured to be coupled to the higher-level common node in the section through its corresponding pick-off switch.

[0374] 68. The charged particle detector of clause 67, further comprising interconnect switches in the higher level located between each pair of adjacent ones of the plurality of sections.

[0375] 69. The charged particle detector of clause 67, further comprising an inter-section element switch between each pair of adjacent sensing elements across two adjacent sections, each inter-section element switch forming part of the lower level.

[0376] 70. A charged particle beam device comprising:

[0377] a charged particle beam source configured to generate a primary charged particle beam;

[0378] a charged particle optical system configured to direct the primary charged particle beam to a sample surface to inspect the sample surface;

[0379] a charged particle detector configured to detect charged particles returning from the sample surface, wherein the charged particle detector comprises a first sensing element and a second sensing element;

[0380] a first inter-element switch configured to be disabled between the first sensing element and the second sensing element to prevent charge from flowing between the first sensing element and the second sensing element via the first inter-element switch, the first inter-element switch forming part of a lower level of a switch matrix;

[0381] a first pick-off switch configured to be enabled between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level via the first pick-off switch; and

[0382] a second pick-off switch configured to be disabled between the second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level via the second pick-off switch;

[0383] Wherein the first sensing element and the second sensing element are coupled to a common analog signal path of the higher-level detector.

[0384] 71. The charged particle beam apparatus of clause 70, wherein:

[0385] The charged particle detector includes a plurality of sensing elements, including the first sensing element and the second sensing element;

[0386] The plurality of sensing elements are divided into a plurality of partial sensing elements by interconnection switches between each sensing element; and

[0387] Each interconnect switch of the plurality of interconnect switches forms part of the higher level.

[0388] 72. The charged particle beam apparatus of clause 71, wherein:

[0389] the first sensing element forming part of a first portion of the plurality of portions;

[0390] the second sensing element forms part of a second portion of the plurality of portions; and

[0391] By enabling the first interconnection switch between the first portion and the second portion, the first sensing element and the second sensing element are coupled to a common analog signal path of a detector at the higher level.

[0392] 73. The charged particle beam apparatus of clause 72, wherein:

[0393] The higher level includes a readout switch coupled to a signal processing circuit of the charged particle detector.

[0394] 74. The charged particle beam apparatus of clause 73, wherein:

[0395] the first interconnect switch being located between the first pick-off switch and the read-out switch on the common analog signal path; and

[0396] The first interconnect switch is not located between the second pick-off switch and the readout switch on the common analog signal path.

[0397] 75. The charged particle beam apparatus of clause 71, wherein:

[0398] The first sensing element and the second sensing element form part of a first portion of the plurality of portions;

[0399] The first sensing element is coupled to a common analog signal path of the detector at a first node of the higher level through the first pick-off switch; and

[0400] The second sensing element is coupled to a common analog signal path of the detector at a first node of the higher level through the second pick-off switch.

[0401] 76. The charged particle beam apparatus according to clause 75, further comprising:

[0402] a second inter-element switch configured to be enabled between the second sensing element and the third sensing element of the charged particle detector to allow charge to flow between the third sensing element and the second sensing element via the second inter-element switch, the second inter-element switch forming part of the lower level; wherein:

[0403] The third sensing element forms a part of a second part of the plurality of parts.

[0404] 77. The charged particle beam apparatus of clause 76, further comprising:

[0405] A third pick-off switch is configured to be disabled between the third sensing element and the second node of the higher level to prevent charge from flowing between the third sensing element and the second node via the third pick-off switch.

[0406] 78. The charged particle beam apparatus of clause 70, further comprising:

[0407] a third pick-up switch configured to be disabled between the third sensing element and the first node to prevent charge from flowing between the third sensing element and the first node via the third pick-up switch; and

[0408] a ground switch configured to be enabled between the third sensing element and a ground connection to prevent charge from accumulating at the third sensing element,

[0409] The third sensing element forms a part of a first part among the plurality of parts.

[0410] 79. The charged particle beam device of clause 70, wherein the first sensing element and the second sensing element comprise PIN diodes.

[0411] 80. The charged particle beam apparatus of clause 70, further comprising:

[0412] Charged particle beam systems;

[0413] Wherein, the charged particle detector is a part of the charged particle beam system.

[0414] 81. The charged particle beam apparatus of clause 80, wherein the charged particle beam system is a SEM inspection tool.

[0415] 82. The charged particle beam apparatus according to clause 70, wherein the charged particle beam apparatus is configured to:

[0416] determining a size, shape or position of a beam spot on a surface of the charged particle detector;

[0417] assigning the first sensing element and the second sensing element to the common analog signal path according to the determined size, shape or position of the beam spot; and

[0418] selecting a switch configuration according to the assignment;

[0419] Wherein the switch configuration includes the first inter-element switch being disabled, the first pick-up switch being enabled, and the second pick-up switch being enabled.

[0420] 83. The charged particle beam apparatus of clause 82, wherein the charged particle beam apparatus is configured to select the switch configuration based on parasitic parameters of the switch configuration.

[0421] 84. A charged particle beam device comprising:

[0422] a charged particle beam source configured to generate a primary charged particle beam;

[0423] a charged particle optical system configured to direct the primary charged particle beam to a sample surface to inspect the sample surface;

[0424] a charged particle detector configured to detect charged particles returning from the sample surface, wherein the charged particle detector comprises the first sensing element, the second sensing element and the third sensing element;

[0425] a first pick-off switch configured to be enabled between the first sensing element and the first node of a higher level of the switch matrix to allow charge to flow between the first sensing element and the first node via the first pick-off switch, the first sensing element being configured to receive charged particles of the first beam spot;

[0426] a first inter-element switch configured to be enabled between the second sensing element and the third sensing element to allow charge to flow between the second sensing element and the third sensing element through the first inter-element switch, the second sensing element and the third sensing element being configured to receive the charged particles of the second beam spot;

[0427] a second pick-off switch configured to be disabled between the second sensing element and the first node to prevent charge from flowing between the second sensing element and the first node via the pick-off switch; and

[0428] A third pick-off switch is configured to be enabled between the third sensing element and the second node of a higher level of the switch matrix to allow charge to flow between the third sensing element and the second node via the third pick-off switch.

[0429] 85. The charged particle beam apparatus of clause 84, wherein:

[0430] The first node is a common node of the higher level in the first portion of sensing elements, the first portion including the first sensing element and the second sensing element; and

[0431] The second node is a common node of the higher level in the second portion of sensing elements, and the second portion includes the third sensing element.

[0432] 86. The charged particle beam apparatus of clause 85, further comprising:

[0433] A first interconnect switch is configured to be disabled between the first node and the second node to prevent charge from flowing in the higher level between the first node and the second node via the first interconnect switch.

[0434] 87. The charged particle beam apparatus of clause 84, further comprising:

[0435] a second inter-element switch configured to be disabled between a fourth sensing element and at least one of the first sensing element and the second sensing element to prevent charge from flowing between the fourth sensing element and at least one of the first sensing element and the second sensing element; and

[0436] A fourth pick-up switch is configured to be disabled between the fourth sensing element and the first node to prevent charge from flowing between the fourth sensing element and the first node via the fourth pick-up switch.

[0437] 88. The charged particle beam apparatus of clause 84, further comprising:

[0438] a first readout switch configured to be enabled between the higher level and the first signal processing circuit to allow the first signal to reach the first signal processing circuit, the first signal being representative of at least a charge from the first sensing element; and

[0439] A second readout switch is configured to be enabled between the higher level and the second signal processing circuit to allow the second signal to reach the second signal processing circuit, the second signal being representative of at least the charge from the second sensing element.

[0440] 89. The charged-particle beam apparatus of clause 88, wherein one of the first signal processing circuit and the second signal processing circuit comprises an analog-to-digital converter (ADC).

[0441] 90. The charged particle beam apparatus according to clause 88, wherein the charged particle beam apparatus is configured to:

[0442] determining a first characteristic of the first beam spot based on the first signal; and

[0443] A second characteristic of the second beam spot is determined based on the second signal.

[0444] 91. The charged particle beam apparatus of clause 90, wherein:

[0445] The first characteristic comprises an intensity of the first beam spot; and

[0446] The second characteristic includes an intensity of the second beam spot.

[0447] A non-transitory computer readable medium storing a controller (e.g., Figure 1 The controller 109 or Figure 8 Instructions of a processor of a controller 804 in the embodiment of the present disclosure. For example, instructions stored in a non-transitory computer readable medium can be executed by circuits of the controller to partially or fully execute Fig.12 Method 1200. Alternatively, instructions stored in a non-transitory computer readable medium may be executed by circuitry of a controller to perform any of the processes disclosed herein. Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, a hard disk, a solid-state drive, a magnetic tape or any other magnetic data storage medium, a compact disk read-only memory (CD-ROM), any other optical data storage medium, any physical medium with a pattern of holes, a random access memory (RAM), a programmable read-only memory (PROM) and an erasable programmable read-only memory (EPROM), a FLASH-EPROM or any other flash memory, a non-volatile random access memory (NVRAM), a cache, a register, any other memory chip or cartridge memory and networked versions thereof.

[0448] It should be understood that the embodiments of the present disclosure are not limited to the exact configurations described above and shown in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof. The present disclosure has been described in conjunction with various embodiments, and other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The description and examples should be regarded as exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

Claims

1. A charged particle beam device, comprising: a charged particle beam source configured to generate a primary charged particle beam; a charged particle optical system configured to direct the primary charged particle beam to a sample surface to inspect the sample surface; a charged particle detector configured to detect charged particles returning from the sample surface, wherein the charged particle detector comprises a first sensing element and a second sensing element; as well as A controller includes one or more processors and is configured to cause the charged particle beam device to perform the following: disabling a first inter-element switch between the first sensing element and the second sensing element to prevent charge from flowing between the first sensing element and the second sensing element via the first inter-element switch, the first inter-element switch forming part of a lower level of a switch matrix; enabling a first pick-off switch between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level via the first pick-off switch; as well as enabling a second pick-off switch between a second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level via the second pick-off switch; Wherein the first sensing element and the second sensing element are coupled to a common analog signal path of the detector at the higher level.

2. The charged particle beam device according to claim 1, wherein: The charged particle detector comprises a plurality of sensing elements, the plurality of sensing elements comprising the first sensing element and the second sensing element; The plurality of sensing elements are divided into a plurality of sections of sensing elements by interconnecting switches between each section of the sensing elements; as well as Each interconnect switch of the plurality of interconnect switches forms part of the higher level.

3. The charged particle beam device according to claim 2, wherein: the first sensing element forming part of a first portion of the plurality of portions; the second sensing element forming part of a second portion of the plurality of portions; and The first sensing element and the second sensing element are coupled to a common analog signal path of the detector at the higher level by enabling a first interconnection switch between the first portion and the second portion.

4. The charged particle beam device according to claim 3, wherein: The higher level includes a readout switch coupled to a signal processing circuit of the charged particle detector.

5. The charged particle beam device according to claim 4, wherein: the first interconnect switch being located between the first pick-off switch and the read-out switch on the common analog signal path; The first interconnect switch is not located between the second pick-off switch and the readout switch on the common analog signal path.

6. The charged particle beam device according to claim 2, wherein: The first sensing element and the second sensing element form part of a first portion of the plurality of portions; The first sensing element is coupled to the common analog signal path of the detector at the first node of the higher level through the first pick-off switch; and The second sensing element is coupled to the common analog signal path of the detector at the first node of the higher level through the second pick-off switch.

7. The charged particle beam device according to claim 6, wherein the controller is further configured to cause the charged particle beam device to execute: enabling a second inter-element switch between the second sensing element and a third sensing element of the charged particle detector to allow charge to flow between the third sensing element and the second sensing element via the second inter-element switch, the second inter-element switch forming part of the lower level; wherein: The third sensing element forms a part of a second part of the plurality of parts.

8. The charged particle beam device according to claim 7, wherein the controller is further configured to cause the charged particle beam device to execute: A third pick-up switch between the third sensing element and a second node of the higher level is disabled to prevent charge from flowing between the third sensing element and the second node via the third pick-up switch.

9. The charged particle beam device according to claim 1, wherein the controller is further configured to cause the charged particle beam device to perform the following: disabling a third pick-up switch between a third sensing element and the first node to prevent charge from flowing between the third sensing element and the first node via the third pick-up switch; and enabling a ground switch between the third sensing element and a ground connection to prevent charge accumulation at the third sensing element, Wherein the third sensing element forms a part of the first part of the plurality of parts. 10 . The charged particle beam apparatus of claim 1 , wherein the first sensing element and the second sensing element comprise PIN diodes.

11. The charged particle beam apparatus of claim 1, wherein the charged particle detector is part of a charged particle beam system.

12. The charged particle beam apparatus of claim 11, wherein the charged particle beam system is a SEM inspection tool.

13. The charged particle beam device according to claim 1, wherein the controller is further configured to cause the charged particle beam device to perform the following: determining a size, shape or position of a beam spot on a surface of the charged particle detector; assigning the first sensing element and the second sensing element to the common analog signal path based on the determined size, shape, or position of the beam spot; as well as selecting a switch configuration based on the assignment; Wherein the switch configuration includes the first inter-element switch disabled, the first pick-off switch enabled, and the second pick-off switch enabled.

14. Charged particle beam apparatus according to claim 13, wherein the switch configuration is selected based on parasitic parameters of the switch configuration.

15. A non-transitory computer readable medium storing a set of instructions executable by at least one processor of a device to cause the device to perform a method comprising: disabling a first inter-element switch between a first sensing element and a second sensing element of the charged particle detector to prevent charge from flowing between the first sensing element and the second sensing element via the first inter-element switch, the first inter-element switch forming part of a lower level of a switch matrix; enabling a first pick-off switch between the first sensing element and a higher level of the switch matrix to allow charge to flow between the first sensing element and the higher level via the first pick-off switch; as well as enabling a second pick-off switch between the second sensing element and the higher level to allow charge to flow between the second sensing element and the higher level via the second pick-off switch; Wherein the first sensing element and the second sensing element are coupled to a common analog signal path of the detector at the higher level.

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