Field Programmable Detector Array

Abstract

Systems and methods for implementing a detector array are disclosed. According to certain embodiments, a substrate includes a plurality of sensing elements (501-503), which includes a first element (502) and a second element (503); and a switching region (3009) between the first element and the second element, configured to connect the first element and the second element. The switching region may be controlled based on a signal generated in response to electrons having a predetermined amount of energy being received by the sensing elements.

Description

[0001] This application is a divisional application of a Chinese patent application with an international filing date of September 14, 2018, a national application number of 201880060358.X, and an invention title of "Field Programmable Detector Array".

[0002] Cross - Reference to Related Applications

[0003] This application claims priority to U.S. Application No. 62 / 560,135, filed on September 18, 2017, the entire content of which is incorporated herein by reference. Technical Field

[0004] The present disclosure generally relates to the field of detector arrays, and more particularly to field programmable detector arrays suitable for charged particle detection. Background Art

[0005] Detectors are used in various fields to sense physically observable phenomena. For example, electron microscopes are useful tools for observing the surface topography and composition of samples. In charged particle beam tools for microscopy, charged particles are directed onto a sample and can interact with the sample in various ways. For example, after impinging on the sample, secondary electrons, backscattered electrons, Auger electrons, X-rays, visible light, etc. can be scattered from the sample and detected by a detector. The scattered particles can form a beam incident on the detector.

[0006] Detectors include an active region in which a current is generated in response to being struck by charged particles. The instantaneous current generated by the detector provides a direct measurement of the flux on the active surface. Some exemplary types of detectors include point detectors and area detectors. A point detector includes a single region and a single channel for reading out the output. A point detector can thus read out data at a very high speed and can be limited only by the readout speed of the coupled electronics. However, a point detector averages the detection signal over the entire active region and thus does not provide spatial information about the detection signal.

[0007] Area detectors have been developed, which can provide spatial information but are more complex and expensive than point detectors. Area detectors are typically pixelated to form a grid of discrete detection elements. The physical arrangement of an area detector can include a plurality of pixels, each pixel including an active region that is surrounded by isolation regions to separate it from adjacent pixels. The active region is the total area that is radiation sensitive and available for sensing.

[0008] In an electron beam detector applicable to a multi-beam wafer inspection system, a detector including a plurality of point detectors may be provided. The detector may receive electrons from a sample and convert the electron beam intensity into an electrical signal so that an image of the sample can be reconstructed. In existing systems, each beam or beamlet of a multi-beam system has a corresponding electron sensing element in the detector. This system requires precise control to align each sensing element of the detector array with a beam.

[0009] Some additional disadvantages of existing electron detectors based on point detectors may be that these detectors cannot provide any information on how the electron optical subsystem is performing. These detectors cannot compensate for any drift and defects in the electron optical subsystem.

[0010] One type of area detector includes a detector array that provides a plurality of electron sensing elements for detecting one or more electron beams. The detector array can address some of the problems of point detectors. Also, such a detector array having a plurality of electron sensing elements associated with a beam can provide a certain degree of flexibility. For example, the detector array can change which pixels are associated with a beam. Separated groups of pixels formed in some applications are advantageous. However, even such a detector array faces the following disadvantages: the detector array is complex, difficult to manufacture, has large dead zones, and is difficult to scale.

[0011] Thus, existing electron detectors can be classified into two groups. For example, one group has a simple arrangement that is easy to manufacture but has no flexibility. The other group has a complex arrangement that has flexibility but is difficult to manufacture and requires large-scale complex signal conditioning and signal routing circuits. The latter prevents further expansion of the wafer inspection system. Summary of the Invention

[0012] Embodiments of the present disclosure provide systems and methods for charged particle detection. In one embodiment, a detection system is provided. The detection system may include a detector.

[0013] In some embodiments, the detector may include a substrate having a plurality of sensing elements. Among the sensing elements may be a first element and a second element. The substrate may also include a switching region configured to connect the first element and the second element. The first element may be configured to generate a first signal in response to the first element detecting a beam, and the second element may be configured to generate a second signal in response to the second element detecting a beam. The switching region may be configured to be controlled based on the first signal and the second signal.

[0014] In some embodiments, a detector may include a sensor layer having an array of sensing elements, the array of sensing elements including a first element and a second element, wherein the first element and the second element are adjacent. The sensor layer may further include a switching region between the first element and the second element. The detector may further include a circuit layer having one or more circuits that are electrically connected to the first element and the second element. The one or more circuits may be configured to: generate a first status indicator when the first element receives a charged particle having a predetermined amount of energy; generate a second status indicator when the second element receives a charged particle having a predetermined amount of energy; and control the switching region based on the first status indicator and the second status indicator.

[0015] In some embodiments, a detector system may include a detector array and a switching region, the detector array having a plurality of sensing elements, the plurality of sensing elements including a first element and a second element, and the switching region being configured to connect the first element and the second element. The detector system may further include one or more circuits configured to generate a first signal in response to the first element detecting a beam and a second signal in response to the second element detecting a beam. A controller may be provided that is connected to the one or more circuits.

[0016] According to some embodiments, an arrangement may be implemented that eliminates the trade - off between the number of pixels and detector manufacturing. A detector with a high number of pixels may be provided without corresponding manufacturing difficulties.

[0017] Additional objects and advantages of the disclosed embodiments will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the embodiments. The objects and advantages of the disclosed embodiments may be realized and obtained by means of the elements and combinations particularly pointed out in the appended claims. However, the exemplary embodiments of the present disclosure do not necessarily need to achieve such exemplary objects and advantages, and some embodiments may not achieve any of the stated objects and advantages.

[0018] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and do not limit the disclosed embodiments claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram illustrating an exemplary electron beam inspection (EBI) system in accordance with an embodiment of the present disclosure.

[0020] Figure 2 is a schematic diagram illustrating an exemplary electron beam tool in accordance with an embodiment of the present disclosure, the electron beam tool being part of an exemplary Figure 1 electron beam inspection system.

[0021] Figures 3A - 3E FIG. is a diagram illustrating an exemplary surface of a detector array in accordance with an embodiment of the present disclosure.

[0022] Figures 4A - 4E FIG. is a diagram illustrating a cross-sectional view of a detector taken along line A of Figure 3D or Figure 3E in accordance with an embodiment of the present disclosure.

[0023] Figure 5 FIG. is a diagram illustrating a cross-sectional view of a detector in accordance with an embodiment of the present disclosure.

[0024] Figure 6A and Figure 6B FIG. is a circuit diagram illustrating a sensor layer and a circuit layer of a detector in accordance with an embodiment of the present disclosure.

[0025] Figure 7 FIG. is a simplified circuit schematic diagram illustrating an exemplary detector array in accordance with an embodiment of the present disclosure.

[0026] Figure 8 FIG. is a diagram illustrating one or more circuits related to position data of sensing elements in accordance with an embodiment of the present disclosure.

[0027] Figure 9 FIG. is a diagram illustrating a detection system using a detector array including a plurality of sensing elements in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which like numerals refer to like elements throughout unless otherwise indicated. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the present invention. Instead, they are merely examples of apparatus and methods consistent with aspects related to the subject matter recited in the appended claims.

[0029] Embodiments of the present disclosure provide a detector having an array architecture. The detector may support field reconfiguration of sensing elements included on an array surface of the detector. The detector may include switching elements, such as switches formed between a pair of sensing elements that control the connection between the two sensing elements in the pair.

[0030] The switches configured to connect two sensing elements may be formed within a sensing layer of the detector array. In this way, the detector array eliminates the need for a separate switch matrix.

[0031] The switching elements may include transistors, e.g., MOSFETs. The MOSFETs may have gates controlled by logic elements.

[0032] The sensing elements can be formed into any number of groups, each group having any shape and any number of sensing elements. The control circuitry for each switch can be located next to each corresponding switch. The control circuitry can include logic elements. The switches between a pair of sensing elements can be addressed by row control and / or wire control routing.

[0033] An array of sensing elements can be formed as a sensor layer in a substrate. The control circuitry can be formed as a circuit layer in the substrate. In an arrangement consistent with aspects of the present disclosure, the interconnects in the circuit layer can be simplified. The output signal of each group of sensing elements can be routed through a plurality of output lines connected to that group. The output lines, together with the connections between the sensing elements formed by the switches in the group, can form a network having a low equivalent output series resistance and series inductance. For example, in some embodiments, compared to a conventional area detector array, the control circuitry can form a network having a reduced equivalent output series resistance and series inductance. The output impedance of the grouped sensing elements can be reduced, facilitating broadband operation.

[0034] Embodiments of the present disclosure provide an electron beam tool having an electron detector. A circuit layer can be provided that is coupled to the electron detector. The electron detector can be configured to receive backscattered primary electrons and secondary electrons emitted from a sample. The received electrons form one or more beam spots on the surface of the detector. The surface of the detector can include a plurality of electron sensing elements configured to generate an electrical signal in response to receiving electrons.

[0035] In some embodiments, the circuit layer can include a preprocessing circuit system and a signal processing circuit system that are used to configure the grouping of the plurality of electron sensing elements. For example, the preprocessing circuit system and the signal processing circuit system can be configured to generate an indication related to the amplitude of the generated electrical signal. Such a circuit system can include logic blocks, such as gates associated with two of the plurality of sensing elements. The gates can be controlled such that the two sensing elements are connected or disconnected via a switching element between the two sensing elements. The electrical signal generated from the sensing elements can be configured to pass through the switching element. A determination can be made based on the electrical signal from the sensing elements.

[0036] A postprocessing circuit system can be configured to interact with a controller that is configured to obtain an image of the beam or beam wave based on the output of the sensing elements. The controller can reconstruct the image of the beam. The controller can be configured to determine beam boundaries (e.g., the primary and secondary boundaries of the beam spot) based on the reconstructed image.

[0037] Further implementations of the post - processing circuit system may include one or more circuits that may be configured to determine which of the electron sensing elements are located within the boundary (e.g., primary boundary) of the beam spot based on the generated indications from the pre - processing circuit system. Processing may be performed to generate a value representative of the beam spot intensity based on the determined primary boundary. In some embodiments, grouping may be used to determine which of the electron sensing elements are located outside the primary boundary of the beam spot. Based on the outputs of the sensing elements determined to be outside the primary boundary, a noise signal may be estimated. When generating the intensity data of the beam spot, the post - processing circuit system may compensate for the estimated noise signal.

[0038] Grouping of the sensing elements may be based on the electrical signals generated by the sensing elements in response to being struck by electrons of the electron beam. The grouping may be based on the electrical signals passing through a switching element that connects adjacent sensing elements. The grouping may also be based on a determination by the post - processing circuit system. For example, in some embodiments, the primary beam spot boundary and / or the secondary beam spot boundary may be determined based on the output signals of the sensing elements.

[0039] Local control logic associated with a pixel may generate an indication of the signal level of the corresponding sensing element. This indication may be used to determine whether two adjacent sensing elements should be connected by a switching element. In this way, groups may be formed. Based on the formed groups of sensing elements, the primary boundary may be determined. Additionally, in some embodiments, gradient information may be obtained and used to determine the secondary boundary.

[0040] Due to different generation processes, electrons of the incident electron beam may have different properties (e.g., different energies). The distribution or concentration of electrons with different properties may vary at different locations. Thus, within the electron beam, the intensity pattern in the detected electron beam spot may correspond to the primary boundary or the secondary boundary. The primary beam spot boundary and the secondary beam spot boundary may be used to group the output signals of the corresponding electron sensing elements. Groups may be formed such that their geometric arrangement matches the pattern of the corresponding electron beam spot. As an example, the portion of the electron beam spot detected by the electron sensing elements within the secondary beam boundary may consist almost entirely of backscattered electrons, while the portion of the electron beam spot detected by the electron sensing elements between the primary beam boundary and the secondary beam boundary may consist almost entirely of secondary electrons. Thus, the formed groups may yield overall intensity information of the detected beam, as well as intensity information corresponding to the backscattered electron and secondary electron portions of the electron beam. Accordingly, some embodiments may provide information about the detected electron beam spot and the properties of the sample under study.

[0041] As used herein, unless otherwise expressly stated and infeasible, the term "or" encompasses all possible combinations. For example, if it is stated that a database can include A or B, then unless otherwise expressly stated or infeasible, the database can include A, or B, or A and B. As a second example, if it is stated that a database can include A, B, or C, then unless otherwise expressly stated or infeasible, the database can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0042] Reference will now be made in detail to example embodiments shown in the accompanying drawings. Although the following embodiments are described in the context of using an electron beam, the present disclosure is not limited thereto. Other types of charged particle beams can be similarly applied. In addition, detectors consistent with aspects of the present disclosure can be applied to environments for sensing x-rays, photons, and other forms of energy.

[0043] Now refer to Figure 1 , Figure 1 which shows an exemplary electron beam inspection (EBI) system 100 in accordance with an embodiment of the present disclosure. As Figure 1 shown, the EBI system 100 includes a main chamber 101, a load / lock chamber 102, an electron beam tool 104, and an equipment front-end module (EFEM) 106. The electron beam tool 104 is located within the main chamber 101. The EFEM 106 includes a first feed port 106a and a second feed port 106b. The EFEM 106 can include additional feed ports. The first feed port 106a and the second feed port 106b receive wafer front-opening unified pods (FOUPs) that contain wafers (e.g., semiconductor wafers or wafers made of other materials) or samples to be inspected (wafers and samples are hereinafter collectively referred to as "wafers").

[0044] One or more robotic arms (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) that removes gas molecules from the load / lock chamber 102 to achieve a first pressure below atmospheric pressure. After achieving the first pressure, one or more robotic arms (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) that removes gas molecules from the main chamber 101 to achieve a second pressure below the first pressure. After achieving the second pressure, the wafer undergoes inspection by the electron beam tool 104. The electron beam tool 104 can be a single-beam system or a multi-beam system. A controller 109 is electrically connected to the electron beam tool 104. The controller 109 can be a computer configured to perform various controls of the EBI system.

[0045] Now refer to Figure 2 , Figure 2 which illustrates an electron beam tool 104 (also referred to herein as device 104), the electron beam tool 104 including an electron source 202, a gun aperture 204, a bunching lens 206, a primary electron beam 210 emitted from the electron source 202, a source conversion unit 212, multiple beamlets 214, 216, and 218 of the primary electron beam 210, a primary projection optical system 220, a wafer stage ( Figure 2 not shown in), multiple secondary electron beams 236, 238, and 240, a secondary optical system 242, and an electron 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 electron detection device 244 may include detection sub-regions 246, 248, and 250.

[0046] The electron source 202, the gun aperture 204, the bunching lens 206, the source conversion unit 212, the beam splitter 222, the deflection scanning unit 226, and the objective lens 228 may be aligned with the primary optical axis 260 of the device 104. The secondary optical system 242 and the electron detection device 244 may be aligned with the secondary optical axis 252 of the device 104.

[0047] The electron source 202 may include a cathode, an extractor, or an anode, where primary electrons may be emitted from the cathode and extracted or accelerated to form a primary electron beam 210 having an intersection point (virtual or real) 208. The primary electron beam 210 may be visualized as being emitted from the intersection point 208. The gun aperture 204 may block the peripheral electrons of the primary electron beam 210 to reduce the Coulomb effect. The Coulomb effect may cause an increase in the size of the probe spots 270, 272, and 274.

[0048] The source conversion unit 212 may include an array of image forming elements ( Figure 2 not shown in) and an array of beam limiting apertures ( Figure 2 not shown in). The array of image forming elements may include an array of micro deflectors or microlenses. The array of image forming elements may utilize the multiple beamlets 214, 216, and 218 of the primary electron beam 210 to form multiple parallel images (virtual or real) of the intersection point 208. The array of beam limiting apertures may limit the multiple beamlets 214, 216, and 218.

[0049] The condenser lens 206 can focus the primary electron beam 210. By adjusting the focusing power of the condenser lens 206 or by changing the radial size of the corresponding beam-limiting holes within the beam-limiting hole array, the current of the beam waves 214, 216, and 218 downstream of the source conversion unit 212 can be varied. The objective lens 228 can focus the beam waves 214, 216, and 218 onto the wafer 230 for inspection and can form a plurality of probe spots 270, 272, and 274 on the surface of the wafer 230.

[0050] The beam splitter 222 can be a beam splitter of the Wien filter type, which generates an electrostatic dipole field and a magnetic dipole field. In some embodiments, if the electrostatic dipole field and the magnetic dipole field are applied, the magnitude of the force exerted on the electrons of the beam waves 214, 216, and 218 by the electrostatic dipole field can be equal to the magnitude of the force exerted on the electrons by the magnetic dipole field, and the directions are opposite. Thus, the beam waves 214, 216, and 218 can pass straight through the beam splitter 222 with a zero deflection angle. However, the total dispersion of the beam waves 214, 216, and 218 generated by the beam splitter 222 can also be non-zero. The beam splitter 222 can separate the secondary electron beams 236, 238, and 240 from the beam waves 214, 216, and 218 and direct the secondary electron beams 236, 238, and 240 towards the secondary optical system 242.

[0051] The deflection scanning unit 226 can deflect the beam waves 214, 216, and 218 to scan the probe spots 270, 272, and 274 over the surface area of the wafer 230. In response to the incidence of the beam waves 214, 216, and 218 at the probe spots 270, 272, and 274, the secondary electron beams 236, 238, and 240 can be emitted from the wafer 230. The secondary electron beams 236, 238, and 240 can include electrons having an energy distribution, where the electrons include secondary electrons (energy ≤ 50 eV) and backscattered electrons (energy between 50 eV and the landing energy of the beam waves 214, 216, and 218). The secondary optical system 242 can focus the secondary electron beams 236, 238, and 240 onto the detection sub-regions 246, 248, and 250 of the electron detection device 244. The detection sub-regions 246, 248, and 250 can be configured to detect the corresponding secondary electron beams 236, 238, and 240 and generate corresponding signals for reconstructing an image of the surface area of the wafer 230.

[0052] Now refer to Figure 3A , Figure 3AFIG. illustrates an exemplary structure of a sensor surface 300, which may form a detection surface of an electronic detection device 244. The sensor surface 300 may be divided into four regions 302A-D (a 2×2 rectangular grid), and each region 302 is capable of receiving a corresponding beam spot 304 emitted from a specific position on the wafer 230. All beam spots 304A-D may exhibit an ideal circular shape and have no loci offset. Although four regions are shown, it should be understood that any number of regions may be used. In addition, the division of the sensor surface 300 into four regions is arbitrary. Any selection of sensing elements 306 may be made to form a specific region. The detection sub-regions 246, 248, 250 in the detector 244 may be constituted by such regions.

[0053] Each sensor region may include an array of electronic sensing elements 306. The electronic sensing elements may include, for example, PIN diodes, avalanche diodes, electron multiplier tubes (EMTs), etc. and combinations thereof. In addition, it can be understood that although Figure 3A each region 302 is shown as being separated from each other as a predetermined region having its own sensing element 306, these predetermined regions may not exist (e.g., a surface sensor 400 such as Figure 3C ). For example, instead of having 4 predefined regions, each with 81 sensing elements (a 9×9 grid of sensing elements), the sensor surface may have a 18×18 grid of sensing elements, which can still sense four beam spots.

[0054] The electronic sensing elements 306 may generate a current signal proportional to the electrons received in the sensor region. The preprocessing circuit may convert the generated current signal into a voltage signal (representing the intensity of the received electron beam spot). The preprocessing circuit may include, for example, a high-speed transimpedance amplifier. The processing system may: generate an intensity signal of the electron beam spot by, for example, summing the currents generated by the electronic sensing elements located within the sensor region; correlate the intensity signal with the scan path data of the primary electron beam incident on the wafer; and construct an image of the wafer based on the high correlation.

[0055] Although the electronic sensing elements 306 are described as receiving electrons from an electron beam, in the case of other types of detectors, the sensor surface may be configured to generate a signal in response to receiving other types of radiation. For example, the detector may respond to charged particles having a specific charge. Moreover, the detector may be sensitive to flux, spatial distribution, spectrum, or other measurable properties. Therefore, the detector sensing elements may be configured to generate a signal in response to receiving a certain type or level of energy (e.g., electrons having a predetermined amount of energy).

[0056] In some embodiments, the processing system may selectively sum the signals generated by some of the electron sensing elements 306 to generate an intensity value of the beam spot. This selection may be based on a determination of which of the electron sensing elements are located within the beam spot.

[0057] In some embodiments, the processing system may identify which electron sensing elements are outside the beam spot and which are within the beam spot by identifying the boundaries of the beam spot. For example, referring to Figure 3B , the processing system may identify primary boundaries 312A, 312B and secondary boundaries 314A, 314B for beam spots 304A and 304B, respectively. The primary boundary 312 may be configured to enclose a set of electron sensing elements 306, the signal outputs of which will be included to determine the beam spot intensity.

[0058] The secondary boundary 314 may be configured to enclose the central portion of the beam spot and may be used to provide certain geometric information about the beam spot. The geometric information may include, for example, the shape of the beam spot, one or more loci of the beam spot, etc. Here, a locus may refer to a predetermined position (e.g., the center) within the beam spot. The processing system may also determine the primary boundary 312 based on the secondary boundary 314.

[0059] In addition, based on the locus information, the processing system may also track the drift of the position of the beam spot 304 caused by, for example, defects in the electron optics or the electron optical system. The defects may be defects introduced during the manufacturing or assembly process. In addition, there may be drifts introduced during the long-term operation of the system. The processing system may update the boundary determination and the set of electron sensing elements to be included in the intensity determination to mitigate the impact of the drift on the accuracy of the intensity determination. Additionally, the processing system may track the offset in the electron beam spot.

[0060] The selection of the electron sensing elements 306 may be determined by a specified electron collection ratio for each beam spot. The selection of the electron sensing elements 306 is used to form each set of electron sensing elements enclosed by the primary boundary 312 or the secondary boundary 314. The specified electron collection ratio is related to the overall image signal intensity and signal-to-noise ratio, signal crosstalk of adjacent electron beams, and the corresponding shape and locus of each electron beam spot. The selection of the electron sensing elements may be controlled by, for example, processing circuitry located near the sensing elements or by an external controller. The formation of each set may be static or may vary dynamically. Information on changes in the shape and locus of the beam spot may be used, for example, to monitor the performance of the electron optical system (e.g., the primary projection optical system 220). For example, the information collected about the positioning and shape of the electron beam may be used in adjusting the electron optical system. Thus, although Figure 3BThe beam spot 304B having a shape deviated from a circle is shown, but this type of deviation such as position, shape, and grid information due to drift in the electron optical system or due to defects in components of the electron optical system can be compensated for.

[0061] Now refer to Figure 3D , Figure 3D illustrates an exemplary structure of a sensor surface 500 that can be used on the electron detection device 244. The sensor surface 500 has an array structure including a plurality of sensing elements, the plurality of sensing elements including sensing elements 501, 502, 503, etc., and each sensing element is capable of receiving at least a portion of the beam spot. The sensing elements 501, 502, 503 can be configured to generate an electrical signal in response to receiving energy.

[0062] The sensing elements can include, for example, PIN diodes, avalanche diodes, electron multiplier tubes (EMTs), etc. and combinations thereof. For example, the sensing elements 501, 502, 503 can be electron sensing elements. The electron sensing elements can generate a current signal proportional to the electrons received in the sensor active region. The processing circuit can convert the generated current signal into a voltage signal (representing the intensity of the received electron beam spot). The processing system can: generate an intensity signal of the electron beam spot by, for example, summing the currents generated by the electron sensing elements located within the sensor region, make the intensity signal related to the scan path data of the primary electron beam incident on the wafer, and construct an image of the wafer based on this correlation.

[0063] Figure 3E illustrates Figure 3D an enlarged portion of the region shown. Figure 4A shows Figure 3D and Figure 3E an exemplary structure of the sensor elements presented by a cross-section in the thickness direction of the detector array along the portion A indicated in

[0064] As Figure 4AAs shown, the sensing elements 501, 502, 503 can be configured as PIN diode devices 3000. The PIN diode device 3000 can include a metal layer 3010 as the top layer. The metal layer 3010 is the layer for receiving electrons incident on the electron detection device 244. Thus, the metal layer 3010 is configured to detect the surface. The material of the metal layer 3010 can be, for example, aluminum. When aluminum is used in the metal layer 3010, an oxide layer can be formed on the outside of the surface to protect the electron detection device 244. The PIN diode device 3000 can also include a metal layer 3050 as the bottom layer. The material of the metal layer 3050 can be, for example, copper. The metal layer 3050 can include output lines for carrying the sensing current from each of the sensing elements 501, 502, 503.

[0065] The PIN diode device 3000 can include semiconductor devices. For example, the semiconductor devices constituting the PIN diode device can be fabricated as a substrate having multiple layers. Thus, the sensing elements 501, 502, 503 can be continuous in the cross-sectional direction. The switching region 3009 can be integrated with the sensing elements. Additionally, the sensing elements 501, 502, 503 and / or the switching region 3009 can be configured as multiple discrete semiconductor devices. The discrete semiconductor devices can be configured to be directly adjacent to each other. Thus, even when the sensing elements are configured as discrete ones, the isolation region can be eliminated and the dead zone can be reduced.

[0066] In the operation of the PIN diode device 3000, a P+ region 3020 is formed adjacent to the metal layer 3010. The P+ region 3020 can be a p-type semiconductor layer. An intrinsic region 3030 is formed adjacent to the P+ region 3020. The intrinsic region 3030 can be an intrinsic semiconductor layer. An N+ region 3040 is formed adjacent to the intrinsic region 3030. The N+ region 3040 can be an n-type semiconductor layer. The sensor layer of the electron detection device 244 is formed as the layer of the metal layer 3010, the P+ region 3020, the intrinsic region 3030, the N+ region 3040, and the metal layer 3050.

[0067] The PIN diode device 3000 includes a switching region 3009 formed between two adjacent sensing elements. As Figure 4AAs shown, a switch region 3009 is formed between sensing elements 501 and 502, and another switch region 3009 is formed between sensing elements 502 and 503. Switch formation can occur in the switch region 3009. As an example, an enhancement MOSFET 3001 can be formed in the sensor layer of the PIN diode device 3000 at the switch region 3009. The MOSFET 3001 can include a P+ region 3002, a gate 3004, and a gate oxide 3003. The MOSFET 3001 is configured as a "normally-off" type switch. In the enhancement type, the voltage applied to the gate 3004 increases the conductivity of the device. Thus, without activating the MOSFET 3001, the switch between sensing elements 502 and 503 is off, and sensing elements 502 and 503 are not connected through the MOSFET 3001. By activating the MOSFET 3001, the switch between the sensing elements is turned on (ON) and sensing elements 501 and 502 are connected through the MOSFET 3001. For example, the PIN diode device 3000 can be configured with a MOSFET that can operate in an on state 3098 and an off state 3099. The MOSFET 3001 can be controlled through the gate 3004.

[0068] The process of fabricating a MOSFET such as MOSFET 3001 can, for example, particularly include etching.

[0069] In operation, when electrons are incident on the top surface of the metal layer 3010, the intrinsic region 3030 is filled with charge carriers from the P+ region 3020. As Figure 4A seen, when two adjacent sensing elements (e.g., 501 and 502) are connected, all regions in the irradiated area below the metal layer 3010, including the regions in the switch region 3009, will be activated. Thus, two adjacent sensing elements can be grouped together to collect current in response to incident electrons, while the dead zone between adjacent sensing elements can be eliminated. There is no need to provide isolation regions to separate adjacent sensing elements (e.g., 501 and 502) in the cross-sectional direction.

[0070] As in Figure 3EAs seen in the plan view, the switching region 3009A between the sensing elements 501 and 502 is the activation region for sensing. On the other hand, the switching region 3009B between the active sensing element 502 and the inactive sensing element 503 is not an active region for sensing. The switching region 3009 can span substantially the entire length of the corresponding sensing element. For example, the sensing element can have a rectangular shape extending in a first direction X and a second direction Y. The rectangular sensing element can have a first side extending in the first direction and a second side extending in the second direction. The switching region 3009 can extend along the entire length of the first side. Another switching region 3009 can extend along the entire length of the second side. Additionally, the switching region can extend a length shorter than the first side or the second side. The switching region can be directly adjacent to the sensing element, so that the active region can be continuous.

[0071] It should be understood that the PIN diode can be implemented in various configurations with different arrangements of p-type and n-type semiconductors. For example, Figure 4B 、 Figure 4C 、 Figure 4D and Figure 4E respectively illustrate various forms of diode devices 3100, diode device 3200, diode device 3300, and diode device 3400. Various combinations of MOSFETs between the sensor diode and the diode are illustrated. In Figure 4B and Figure 4E , when Vgs = 0, the MOSFET can be turned off, and when |Vgs| > |Vth|, the MOSFET can be turned on. In some instances, for example, as shown in Figure 4C and Figure 4D , a depletion-type MOSFET can be used as a switch.

[0072] For example, Figure 4B shows the diode device 3100, which includes metal 3110, N+ region 3120, intrinsic 3130, P+ region 3140, metal 3150, enhancement-type MOSFET 3101, N+ region 3102, gate oxide 3103, gate 3104, and gate 3105. The diode device 3100 can be configured with a MOSFET that can operate in an on state 3198 and an off state 3199.

[0073] For example, Figure 4CDiode device 3200 is shown, which includes metal 3210, P+ region 3220, intrinsic 3230, N+ region 3240, metal 3250, depletion-mode MOSFET 3201, P+ region 3202, gate oxide 3203, gate 3204, and gate 3205. Diode device 3200 can be configured to have a MOSFET that is operable in an on state 3298 and an off state 3299.

[0074] For example, Figure 4D Diode device 3300 is shown, which includes metal 3310, N+ region 3320, intrinsic 3330, P+ region 3340, metal 3350, depletion-mode MOSFET 3301, N+ region 3302, gate oxide 3303, gate 3304, and gate 3305. Diode device 3300 can be configured to have a MOSFET that is operable in an on state 3398 and an off state 3399.

[0075] For example, Figure 4E Diode device 3400 is shown, which includes metal 3410, P+ region 3420, intrinsic 3430, N+ region 3440, metal 3450, enhancement-mode MOSFET 3401, P+ region 3402, gate oxide 3403, gate 3404, and gate 3405. Diode device 3400 can be configured to have a MOSFET that is operable in an on state 3498 and an off state 3499.

[0076] Although the above description discusses one or more metal layers, it is obvious that alternatives (e.g., conductive materials) can be used.

[0077] When a detector having a sensor layer formed of multiple sensing elements includes a switching region between adjacent sensing elements, the dead zone can be reduced. For example, when two adjacent elements are connected, the switching region between them is included in the active region for sensing. As will be discussed later, the current induced by electrons incident on the detector surface above the switching region is included in the output signal. Thus, a surface region that might otherwise be provided as an isolation region can be reclaimed as an active sensing region, and the isolation region separates individual pixels. A larger sensing region can increase the detection rate and provide a better signal-to-noise ratio (SNR). In addition, eliminating the isolation region enables more pixels to be formed in a given area. Thus, a higher pixel count can be achieved.

[0078] As Figure 3EAs shown, a cross-shaped region 525 can be provided. The region 525 can be an isolation region to isolate the corners of pixels from pixels that cross each other in the diagonal direction. Various shapes can be used instead of the cross shape. For example, the region 525 can be provided as a square. The region 525 can also be provided as a diagonal line to separate diagonal pixels using as small an area as possible. In some embodiments, the region 525 can be eliminated to further reduce the dead zone.

[0079] Although the sensor surface 500 is depicted as having a rectangular grid arrangement, various geometric arrangements can be used. For example, the sensing elements can be arranged in a hexagonal grid. Thus, individual sensing elements can have corresponding different sizes and shapes. The sensing elements can also be arranged with octagonal tiles, triangular tiles, rhombic tiles, etc. The sensing elements are not necessarily provided in a uniform shape and regular package. For example, pentagonal tiles with semi-regular hexagons can be used. It should be understood that these examples are exemplary and various modifications can be applied.

[0080] Now refer to Figure 5 , Figure 5 A simplified illustration of the layer structure of the detector 600 is shown. The detector 600 can be provided as the detector 244 as Figure 2 shown. The detector 600 can be configured to have a plurality of layers stacked in the thickness direction, which can be substantially parallel to the incident direction of the electron beam. The plurality of layers can include a sensor layer 610 and a circuit layer 620. As described above, the sensor layer 610 can be provided with the sensor surface 500. Sensing elements (e.g., sensing elements 611, 612, and 613) can be provided in the sensor layer 610. Switching elements 619 can be provided between adjacent sensing elements in the cross-sectional direction. The switching elements 619 can be embedded in the sensor layer 610.

[0081] For example, as described above, the sensor layer 610 can be configured as a diode, where the sensing elements 611, 612, and 613 are similar to the sensing elements 501, 502, and 503. Moreover, the switching elements 619 can be configured as transistors (e.g., MOSFET 3001). Each of the sensing elements 611, 612, 613 can include an output for forming an electrical connection to the circuit layer 620. The output can be integrated with the switching element 619 or can be provided separately. The output can be integrated in the bottom layer of the sensor layer 610, and the bottom layer can be a metal layer, such as a metal layer similar to the metal layer 3050.

[0082] The circuit layer 620 is provided adjacent to the sensor layer 610. The circuit layer 620 includes wire routing and various electronic circuit components. The circuit layer 620 can include a processing system. The circuit layer 620 can be configured to receive the output current detected in the sensor layer 610.

[0083] Figure 6A A circuit schematic diagram is shown. The dashed line indicates the division between the sensor die 701 and the circuit die 702. A layout such as that shown in the circuit die 702 can represent, for example, a circuit provided in the circuit layer 620. A layout such as that shown in the sensor die 701 can represent, for example, a plurality of sensing elements with switching elements therebetween. For example, the sensor layer 610 can be configured in the sensor die.

[0084] In Figure 6B Another circuit schematic diagram is shown. As will be discussed later, the layout shown in the circuit die 702 can include an additional comparator 771.

[0085] Figure 7 A simplified circuit diagram is shown. As Figure 7 shown, a plurality of pixels P1, P2, P3, P4 can be provided. The pixels P1, P2, P3, P4 can represent pixels of a sensing array, and each pixel can be associated with a sensing element.

[0086] In an exemplary process of detecting the signal strength from the sensing elements, the sensing elements in the sensor layer are configured to collect the current induced by incident charged particles. Other types of energy conversion can be used. The current is output from the sensing elements to the circuit layer, which is configured to analyze the output from the sensing elements. The circuit layer can include a wiring layout and a plurality of electronic components to analyze the output from the sensing elements.

[0087] The process of signal strength detection will be discussed with reference to Figure 6A One pixel can be associated with one sensing element of the sensing array. Thus, the first pixel is configured to generate a PIN diode current 711. At the start of the process for PIN diode signal strength detection, switches 721 and 731 are set to open, while switch 741 is set to closed. Thus, the voltage of the capacitor 735 can be reset to Vref2.

[0088] Next, switches 721 and 741 are set to open, while switch 731 is set to closed. In this state, the capacitor 735 starts to charge and generates a voltage. The capacitor 735 can be configured to charge for a predetermined period (e.g., t_charge), and after charging, switch 731 is set to open.

[0089] Then, comparator 736 compares the voltage at capacitor 735 with a reference value Vref1. The reference value Vref1 can be set to a predetermined signal level. Based on the reference value, the circuit can be configured to output a signal that indicates that the sensing element is collecting current from the incident electron beam. Thus, the reference value can be a suitable value that indicates that the signal level from the PIN diode is high enough to be considered as collecting current from the incident electron beam included in the beam spot. In comparator 736, if the voltage from capacitor 735 is higher than Vref1, the output signal is sent to block 750.

[0090] Vref1 can be set such that each sensing element can be controlled to be included within the outer boundary of the beam spot. The value t_charge can be determined based on local logic or an external circuit (e.g., via data line 752 communicating with block 750). The logic block and circuit system components can be set such that functions such as signal strength detection and pixel grouping determination can occur locally. However, the signal strength of each sensing element can be collected, and the determination can be made via an external path. For example, the analog signal path and ADC can communicate with an external controller via analog signal lines and data lines.

[0091] As described herein, each pixel in the sensing array can be associated with a sensing element that generates a current based on incident electrons on the sensing element and communicates with a circuit layer. The pixel can be connected to a circuit system such as that discussed above with reference to the first pixel configured to generate PIN diode current 711. Thus, the second pixel can be configured to generate PIN diode current 712, etc. PIN diode current 712 can be connected to corresponding circuit elements, e.g., switch 721b, switch 731b, switch 741b, capacitor 735b, comparator 736b, block 750b, etc.

[0092] Referring again to Figure 6A the generation and setting of the status indicator are discussed. Using the output current from the sensing element, the circuit layer is configured to generate a status indicator. The status indicator can be configured to trigger a function for implementing pixel grouping. Various methods for implementing sensing element grouping can be provided.

[0093] In a first method for grouping, sensing element grouping can be implemented according to a signal strength flag in a local logic circuit. If the first pixel and the second pixel have a strong signal strength, the two pixels can be grouped. For example, both PIN diode current 711 and PIN diode current 712 can have high current values. That is, the voltage at capacitor 735 and the voltage at capacitor 735b can both be higher than Vref1. Then, switch 767 is set to closed, thereby merging the two pixels.

[0094] If at least one of the first pixel and the second pixel has a weak signal, that is, the voltage at capacitor 735 or capacitor 735b is less than Vref1, switch 767 is set to open so that the two pixels are not merged.

[0095] Switch 767 is configured as an element for implementing a switch between two sensing elements. Switch 767 is located in sensor die 701. Switch 767 can be embedded in sensor die 701. Switch 767 can be configured as a transistor (e.g., MOSFET 3001).

[0096] Switch 767 can be triggered by local logic in circuit die 702. The outputs from comparator 736 and from comparator 736b can be routed to a block for activating switch 767. For example, as Figure 6A shown, AND gate 760 is provided. AND gate 760 is arranged in circuit die 702. AND gate 760 is associated with two pixels and with a switch between the two pixels. The outputs from comparators 736 and 736b can be routed directly to, or through other blocks to, AND gate 760. Based on the signals input to AND gate 760 (e.g., status indicator 751 and status indicator 751b), AND gate 760 is configured to switch switch 767. When switch 767 is a transistor (e.g., a field effect transistor), the switch can be switched by applying a voltage to its gate. For example, in Figure 4A the configuration, a voltage can be applied to gate 3004.

[0097] Although an AND gate is illustrated, it should be understood that various components can be used to implement the switching of a switch arranged between sensing elements based on the output signals from the sensing elements. For example, Figure 7is a simplified circuit diagram illustrating the arrangement of four pixels in an array. In the array, the first pixel P1 can be configured to generate a PIN diode current 711 and output a status signal S1 based on the PIN diode current 711. The status signal S1 can correspond to a status indicator 751. The second pixel P2 can be configured to generate a PIN diode current 712 and output a status signal S2 based on the PIN diode current 712. The status signal S2 can correspond to a status indicator 751b. The status signal S1 from the first pixel P1 and the status signal S2 from the second pixel P2 are input to an AND gate 760. The status signal S1 and the status signal S2 can be generated based on signals generated at each of the pixels P1 and P2. For example, a current signal can be induced by electrons incident on the pixel surface. The status signal S1 can be generated based on whether the current at pixel P1 reaches a predetermined threshold. Similarly, the status signal S2 can be generated based on whether the current at pixel P2 reaches a predetermined threshold. The AND gate 760 outputs a signal based on the status signal S1 and the status signal S2 to a switch 767. Thus, the switch 767 is configured to be controlled based on input signals generated from at least two pixels. Such an input signal can be a voltage. Obviously, various other blocks or electrical components can be used to implement the control of the switch 767.

[0098] Similar components can be provided for other pixels of the array. For example, a switch 767d is provided between pixels P3 and P4. Similar to pixels P1 and P2, pixels P3 and P4 can be configured to output status signals S3 and S4, respectively. In addition, a pixel can communicate with multiple other pixels. For example, in addition to the switch 767 configured to connect pixels P1 and P2, a switch 767b can be provided between pixels P1 and P3, and so on. The status signal S1 can be configured to be sent to multiple neighboring pixels.

[0099] In a second method for grouping, the sensing element grouping can be implemented according to an external logic circuit. For example, in Figure 6A and Figure 6B , the block 750 can be a digital logic block. The block 750 can communicate with external components via a data line 752 and an address signal 753. The status indicator 751 can be overwritten by an external logic circuit system via the data line 752 to control the state of the switch 767. Such an external logic circuit system can also be provided in the circuit die 702 or can be provided as a separate system attached to the block 750 by an input / output device.

[0100] In some embodiments, local control logic associated with each pixel generates an indication of the signal level of its corresponding sensing element. This indication can be used to determine whether two adjacent sensing elements should be connected via a MOSFET formed between them. In this way, groups of sensing elements can be formed. Based on the formed groups, a primary boundary can be formed.

[0101] To generate gradient information regarding signal strength, as Figure 6B shown, an additional comparator 771 can be provided. The results from comparator 771 can be fed to logic blocks 750 and 750b. With the arrangement including comparator 771, processing can be performed to generate a value representing the intensity of the beam spot based on the determined primary boundary. Grouping can be performed based on which electron sensing elements are determined to be outside the primary boundary of the beam spot.

[0102] In electron beam imaging, beam wave image acquisition can be performed. The process of image acquisition will be discussed with reference to Figure 6A . Initially, switch 721 and switch 731 are set to open, while switch 741 is set to closed. For each row of the detector array, switch 721 (or the corresponding switch) is sequentially set to closed one by one. By sequentially closing switch 721 and the corresponding switch, an electronic scan of the detector surface can be performed. The scan can be implemented to read the analog signal of each pixel. For example, analog output line 722 can be configured to read through an analog path, output to an external device, or be sent to an analog-to-digital converter (ADC).

[0103] Based on the signal output from analog output line 722, image reconstruction of the beam or beam wave can be achieved. A controller can be used to perform image acquisition based on the reconstructed image. The reconstructed image can be used to determine the boundaries of groups of sensing elements. For example, a group can be defined to correspond to one beam wave. Thus, the total signal intensity of the sensing elements in the group represents the current of that one beam wave. The reconstructed image can also be used to evaluate the performance of the electron optical system. For example, the primary projection optical system 220 and / or the secondary optical system 242 can be adjusted based on the reconstructed image. The reconstructed image can be used to compensate for defects or drifts in the electron optical subsystem.

[0104] In addition, a low-impedance output path for the current signals from groups of pixels can be implemented. For example, multiple switches (e.g., switch 721) can be provided for multiple pixels in the same group. The pixels in the same group can be in close proximity. Multiple analog signal lines such as analog output line 722 can be routed to grouped outputs. Additionally, when multiple analog signal lines are grouped to the same group of multiple pixels, the multiple analog signal lines can be connected.

[0105] Although examples have been discussed with reference to an electron beam inspection system, it should be noted that for optoelectronic image sensor applications, a buffer can be added after switch 721 to improve performance.

[0106] In an exemplary embodiment of the detector array, individual sensing elements in the detector array can be enabled or disabled. In normal operation for electron beam imaging, certain sensing elements are enabled to detect the incident beam current.

[0107] For example, referring to Figure 6A , a pixel can be enabled when the voltage at capacitor 735 is greater than or equal to Vref1. For example, in an override mode, a pixel can also be enabled by an external logic circuit. In the override mode, depending on the control signal from the external logic, switch 721 can be opened or closed to determine the signal output routing. In the override mode, switch 731 can be set to open, and switch 741 can be set to closed.

[0108] When the voltage at capacitor 735 is lower than Vref1, the pixel can be disabled. For example, in the override mode, the pixel can also be disabled by an external logic circuit. In the override mode for disabling, switch 721 can be set to open. Switches 731 and 741 can be set to closed.

[0109] Operation in the override mode can be performed, for example, when it is determined that there is crosstalk in the sensing elements. Crosstalk may occur when the beam overlaps with adjacent beam portions due to aberration, dispersion, etc. In some embodiments, the processing system can detect the occurrence of partial overlap based on the primary beam spot boundary or the secondary beam spot boundary. When determining the intensity value of the beam spot, the processing system can exclude the outputs from some sensing elements located in the region where the beam spots overlap.

[0110] Now referring to Figure 8 , Figure 8 illustrates a graph related to the position data of the sensing elements. The detector array can include a plurality of sensing elements arranged to form J×K pixels with M×N channels. A single sensing element can be represented by pixel P1. Pixel P1 has address column AC_1. Pixel P2 has address column AC_2, and so on. For example, in an exemplary array with J×K pixels, pixel P JK has address column AC_J and address row AR_K. Each column can have an analog column. For example, pixel P1 has analog column AnC_1, which carries the output current from the sensing element of pixel P1.

[0111] Each sensing element can be selected by address column and address row signals. For example, pixel P1 can be addressed by AC_1 and AR_1.

[0112] Data can be read and written to each local logic circuit associated with each sensing element via data line signals. For example, data can be sent to and received from pixel P1 via data line DR_1. Digital logic DL can control the read / write, etc. of the data.

[0113] Analog signals from each sensing element can travel through corresponding analog column lines to reach multiplexer Mux. The multiplexer Mux can be located within the detector array. The multiplexer Mux can also be external to the detector array. The multiplexer Mux can have J inputs and M×N outputs.

[0114] Pixels can be identified and grouped by their respective address line information. Any two pixels in the detector array can communicate. Thus, grouping between any number of pixels at any location can be achieved.

[0115] The position information of multiple sensing elements can be used in various ways. For example, the position information can be related to beam intensity to determine the boundaries of the beam spot. Additionally, based on the positions of the electronic sensing elements that cause the signal intensity comparator to make a decision, the processing system can identify the locations where transitions between intensity gradients on the sensor surface occur. The intensity gradient information can be used to perform determinations involving primary and secondary boundaries. In some embodiments, the position data can also be used to operate in an override mode to control a switching element between two pixels independently of the local logic.

[0116] The processing system (e.g., a processor embedded in circuit die 702 or externally connected) can perform processing to determine the identified locations as part of the beam boundary. The processing system can include an arrangement of comparators configured to perform processing based on voltage comparisons for each row and each column of the electronic sensing elements to determine a set of locations on the detector array surface that can constitute the beam boundary.

[0117] In some embodiments, the processing system can also improve the fidelity of image reconstruction by compensating for the effects of noise signals using the boundary information. The processing system can exclude such received signals that are received from the outputs of electronic sensing elements determined to be outside the primary beam boundary. By eliminating random noise signals from electronic sensing elements outside the primary boundary, the fidelity of image reconstruction can be improved.

[0118] In Figure 8In [the figure], the lines interconnecting multiple sensing elements (e.g., the lines illustrated as AC_1, AR_1, DR_1, AnC_1, etc.) can be conductive wires patterned by printing a conductive material on a substrate. The wires can be fabricated in various ways (e.g., by conventional processes used to fabricate MOSFETs). The wires can be part of the circuit layer of the detector array.

[0119] Now refer to Figure 9 , Figure 9 FIG. [the figure] illustrates a detection system 900 that uses a detector array including multiple sensing elements. A detector array having a detector sensor surface 500 can be provided, which can be used on an electronic detection device 244. The detector array can include J×K pixels and have M×N outputs connected to a multiplexer (e.g., multiplexer Mux). As discussed herein, the detector array can be configured as a substrate including a sensor layer and a circuit layer.

[0120] The detector array can be connected to a signal conditioning circuit array 910. The signal conditioning circuit array 910 can have M×N inputs and outputs to match the detector array.

[0121] The signal conditioning circuit array 910 can be connected to a parallel analog signal processing path 920 for providing gain and offset control. The parallel analog signal processing path 920 can have M×N inputs and outputs to match the detector array.

[0122] The parallel analog signal processing path 920 can be connected to a parallel ADC 930, and the parallel ADC 930 can have M×N inputs and outputs to match the detector array.

[0123] The parallel ADC 930 can be connected to a digital control unit 940. The digital control unit 940 can include a controller 941, and the controller 941 can communicate with the parallel analog signal processing path 920, the parallel analog signal processing path 920, and the detector array. The digital control unit 940 can send and receive communications from a deflection and image control (DIC) unit via control signals and a transmitter TX.

[0124] An external controller (e.g., controller 941) can be configured to perform imaging control. For example, the controller 941 can be configured to generate an image of the detected beam wave. Additionally, packets can be determined based on a primary beam spot boundary and a secondary beam spot boundary.

[0125] In some embodiments, a switch matrix may not be provided in the detection system 900. Since switches are integrated in the detector array (e.g., integrated in the sensor layer of the detector array), a more easily expandable configuration can be achieved.

[0126] In addition, since the J×K pixels in the detector are initially grouped into M×N groups, the number of outputs can be reduced. The outputs from the grouped pixels can have a common output. For example, an arrangement with M×N outputs can be implemented. The total number of outputs can be greatly reduced compared to a conventional detector array.

[0127] The detector array can include its own memory such that the detector array can store the arrangement of the plurality of sensing elements and their associated circuitry. For example, the state of the local indicator 751 and the grouping of the sensing elements can be stored in the memory. The state of the switches can be stored in the memory.

[0128] The embodiments can be further described using the following clauses:

[0129] 1. A detector, comprising:

[0130] A substrate including a plurality of sensing elements, the plurality of sensing elements including a first element and a second element; and a switch region configured to connect the first element and the second element,

[0131] wherein the first element is configured to generate a first signal in response to the first element detecting a first charged particle indicative of a beam, and the second element is configured to generate a second signal in response to the second element detecting a second charged particle indicative of the beam, and

[0132] wherein the switch region is configured to be controlled based on the first signal and the second signal.

[0133] 2. The detector according to clause 1, further comprising:

[0134] A sensor die including the above substrate; and

[0135] A circuit die including one or more circuits configured to control the switch region.

[0136] 3. The detector according to any one of clauses 1 and 2, wherein the switch region includes a switch configured to connect the first element and the second element.

[0137] 4. The detector according to any one of clauses 1 to 3, wherein the substrate includes a diode configured to transport charge carriers in the switch region.

[0138] 5. The detector according to any one of clauses 1 to 4, wherein

[0139] the first element is configured to generate a first signal in response to the first element receiving a charged particle having a first predetermined amount of energy, and the second element is configured to generate a second signal in response to receiving a charged particle having a second predetermined amount of energy.

[0140] 6. The detector according to any one of clauses 1 to 4, wherein

[0141] the first element is configured to generate a first signal in response to the first element receiving an electron having a first predetermined amount of energy, and the second element is configured to generate a second signal in response to receiving an electron having a second predetermined amount of energy.

[0142] 7. The detector according to any one of clauses 1 to 6,

[0143] wherein in the thickness direction, the substrate includes a top metal layer and a bottom metal layer, the top metal layer is configured as a detection surface, and

[0144] wherein in cross-section, the entire region between the top metal layer and the bottom metal layer is a charge carrier region.

[0145] 8. The detector according to clause 7, wherein the switching region includes a field effect transistor, and the field effect transistor includes a gate fabricated in the bottom metal layer, or a contact of the gate fabricated in the bottom metal layer.

[0146] 9. A detector, comprising:

[0147] a sensor layer, comprising:

[0148] an array of sensing elements, comprising a first element and a second element, wherein the first element and the second element are adjacent; and

[0149] a switching region between the first element and the second element; and

[0150] a circuit layer, comprising one or more circuits electrically connected to the first element and the second element, the one or more circuits being configured to:

[0151] generate a first status indicator when the first element receives a charged particle having a predetermined amount of energy;

[0152] generate a second status indicator when the second element receives a charged particle having a predetermined amount of energy; and

[0153] control the switching region based on the first status indicator and the second status indicator.

[0154] 10. The detector according to clause 9, wherein

[0155] the circuit is configured to control the switching region between a first state and a second state,

[0156] wherein in the first state, the switching region is part of an active group,

[0157] Wherein in the second state, the switching region is part of the non-active group.

[0158] 11. The detector according to any one of clauses 9 and 10, wherein the switching region includes a transistor.

[0159] 12. The detector according to any one of clauses 9 to 11, wherein in a plan view of the substrate, the first element, the second element, and the switching region are continuous along a first direction in which the first element and the second element are arranged.

[0160] 13. A detector system, comprising:

[0161] A detector array including a plurality of sensing elements, the plurality of sensing elements including a first element and a second element; and a switching region configured to connect the first element and the second element;

[0162] One or more circuits configured to generate a first signal in response to the first element detecting a first charged particle indicative of a beam, and generate a second signal in response to the second element detecting a second charged particle indicative of the beam; and

[0163] A controller connected to any of the one or more circuits.

[0164] 14. The system according to clause 13, wherein

[0165] The controller is configured to control the switching region based on the address of at least one of the first element and the second element.

[0166] 15. The system according to any one of clauses 13 and 14, wherein

[0167] The controller is configured to acquire an image of the beam and generate a command signal based on the image; and

[0168] One or more circuits are configured to control the switching region based on the command signal.

[0169] 16. The system according to any one of clauses 13 to 15, wherein

[0170] The detector array includes a first number of pixels configured to be grouped into a second number of groups, the second number being less than the first number.

[0171] 17. The system according to clause 16, further comprising:

[0172] An array of signal conditioning circuits;

[0173] An array of parallel analog signal processing paths;

[0174] An array of parallel analog-to-digital converters; and

[0175] Digital control unit

[0176] Wherein the signal conditioning circuit array, the parallel analog signal processing path array, the parallel analog-to-digital converter array, and the digital control unit are connected to the detector array via a plurality of channels, and the number of the plurality of channels is greater than or equal to a second number.

[0177] 18. The system according to any one of clauses 13 to 17, wherein the controller is configured to override the local logic of one or more circuits.

[0178] 19. The system according to any one of clauses 13 to 18, wherein the one or more circuits include the controller.

[0179] 20. The system according to any one of clauses 13 to 18, wherein the controller is external to the detector array.

[0180] 21. The system according to any one of clauses 13 to 20, wherein the first element and the second element have a common output.

[0181] 22. The system according to clause 17, wherein the number of the plurality of channels is equal to the second number.

[0182] 23. The detector according to any one of clauses 5 or 6, wherein the first predetermined energy and the second predetermined energy are the same predetermined energy.

[0183] 24. The detector according to any one of clauses 5 or 6, wherein the first predetermined energy and the second predetermined energy are different predetermined energies.

[0184] 25. The detector according to clause 5, wherein the charged particle is an electron.

[0185] The block diagrams in the drawings illustrate the possible architectures, functionality, and operations of systems, methods, and computer hardware / software products according to various exemplary embodiments of the present disclosure. To this end, each block in the flowchart or block diagram may represent a module, segment, or portion of code that includes one or more executable instructions for implementing the specified logical function. It should be understood that in some alternative implementations, the functions indicated in the blocks may not occur in the order indicated in the figures. For example, depending on the functions involved, two consecutive blocks shown may be executed or implemented substantially simultaneously, or the two blocks may sometimes be executed in the reverse order. It should also be understood that each block of the block diagrams, and combinations of these blocks, may be implemented by a system based on dedicated hardware that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0186] It should be understood that the present invention is not limited to the exact construction described above and illustrated in the accompanying drawings, and various modifications and changes can be made without departing from the scope of the present invention. For example, although the exemplary detector has been described and illustrated with respect to an electron beam system, detectors in accordance with aspects of the present disclosure can be applied to photodetector systems, x-ray detector systems, and other detection systems for high-energy ionizing particles. Detectors in accordance with aspects of the present disclosure can be applied to a scanning electron microscope (SEM), a CMOS image sensor, a consumer camera, a dedicated camera, or an industrial-use camera, etc.

[0187] The scope of the present invention is intended to be limited only by the appended claims.

Claims

1. A detector, comprising: a sensor layer, comprising: a sensing element array, comprising a first element and a second element, wherein the first element and the second element are adjacent; and a switching region between the first element and the second element; and a circuit layer, comprising one or more circuits electrically connected to the first element and the second element, the one or more circuits being configured to: generate a first status indicator when the first element receives charged particles having a first predetermined amount of energy; generate a second status indicator when the second element receives charged particles having a second predetermined amount of energy; and control the switching region based on the first status indicator and the second status indicator.

2. The detector according to claim 1, wherein the one or more circuits are configured to control the switching region between a first state and a second state, wherein in the first state, the switching region is part of an active group, wherein in the second state, the switching region is part of a non-active group.

3. The detector according to claim 1 or 2, wherein the switching region comprises a switching element.

4. The detector according to claim 3, wherein the switching element is a transistor.

5. The detector according to claim 3, wherein the switching element is embedded in the sensor layer.

6. The detector according to claim 3, wherein each of the first element and the second element comprises: an output for forming an electrical connection to the circuit layer.

7. The detector according to claim 6, wherein the output is integrated with the switching element or provided separately.

8. The detector according to claim 1 or 2, wherein the first element, the second element, and the switching region are formed in a substrate, and in a plan view of the substrate, the first element, the second element, and the switching region are continuous along a first direction in which the first element and the second element are arranged.

9. The detector according to claim 1 or 2, wherein the first predetermined amount of energy and the second predetermined amount of energy are the same predetermined amount of energy.

10. The detector according to claim 1 or 2, wherein the first predetermined amount of energy and the second predetermined amount of energy are different predetermined amounts of energy.

Images