Thermally assisted testing with advanced charge controller modules in charged particle systems

Abstract

An apparatus, system, and method for providing a beam for controlling charge on a sample surface of a charged particle beam system. In some embodiments, a module including a laser source configured to emit a beam. The beam can illuminate an area adjacent to a pixel on a wafer to indirectly heat the pixel, thereby mitigating a cause of direct photon induced effects at the pixel. An electron beam tool configured to detect defects in a pixel, the defects induced by indirect heating of the pixel.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 63 / 126,430, filed December 16, 2020, the entire contents of which are incorporated herein by reference.

[0002]

[0002] The description herein relates to the field of charged particle beam systems, and more particularly to a system for providing a beam for controlling charge on a sample surface of an inspection system of a charged particle beam system. [Background technology]

[0003]

[0003] During the integrated circuit (IC) manufacturing process, unfinished and finished circuit components are inspected to ensure they are manufactured as designed and are free of defects. Inspection systems that use optical microscopes typically have a resolution on the order of a few hundred nanometers, limited by the wavelength of light. As the physical size of IC components shrinks to less than 100 nanometers, or even less than 10 nanometers, inspection systems capable of higher resolution than those that use optical microscopes are needed.

[0004]

[0004] Charged particle (e.g., electron) beam microscopes, such as scanning electron microscopes (SEMs) or transmission electron microscopes (TEMs), capable of sub-nanometer resolution, serve as practical tools for inspecting IC components with feature sizes of less than 100 nanometers. Using an SEM, electrons from a single primary electron beam or multiple primary electron beams can be focused onto a location of interest on a wafer under inspection. The primary electrons interact with the wafer and can be backscattered or can cause the wafer to emit secondary electrons. The intensity of the electron beam, including the backscattered and secondary electrons, can vary based on the characteristics of the wafer's internal and external structures, thereby indicating whether the wafer is defective. Summary of the Invention

[0005]

[0005] Embodiments of the present disclosure provide apparatus, systems, and methods for providing a beam for controlling charge on a sample surface of a charged particle beam system. In some embodiments, a module configured to emit the beam can illuminate an area adjacent to a pixel on a wafer to indirectly heat the pixel, thereby mitigating the source of direct photon-induced effects at the pixel. An electron beam tool configured to detect defects in a pixel, the defects induced by indirect heating of the pixel.

[0006]

[0006] In some embodiments, the inspection method may include emitting a beam from a module that illuminates an area adjacent to a pixel on the wafer to indirectly heat the pixel, thereby mitigating the cause of direct photon-induced effects in the pixel, and detecting defects in the pixel, where the defects are induced by the indirect heating of the pixel.

[0007] In some embodiments, a non-transitory computer-readable medium may store a set of instructions, executable by at least one processor of the computing device, for causing a computing device to perform an inspection method. The method may include: illuminating an area adjacent to a pixel on a wafer with a beam from a module to indirectly heat the pixel, thereby mitigating a source of direct photon-induced effects in the pixel; and detecting defects in the pixel, wherein the defects are induced by the indirect heating of the pixel. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating an exemplary electron beam inspection (EBI) system consistent with an embodiment of the present disclosure. [Figure 2]

[0009] FIG. 2 is a schematic diagram illustrating an example multi-beam system that is part of the example charged particle beam inspection system of FIG. 1, consistent with an embodiment of the present disclosure. [Figure 3]

[0010] FIG. 1 is a schematic diagram illustrating an exemplary electron beam system consistent with embodiments of the present disclosure. [Figure 4]

[0011] 1 is an exemplary graph illustrating secondary electron yield rate versus landing energy of primary electron beamlets, consistent with embodiments of the present disclosure. [Figure 5]

[0012] FIG. 1 is a schematic diagram illustrating an exemplary voltage contrast response of a wafer, consistent with an embodiment of the present disclosure. [Figure 6]

[0013] 1 is an exemplary PN junction diode consistent with embodiments of the present disclosure. [Figure 7A]

[0014] FIG. 1 is a schematic diagram illustrating an exemplary electron beam system consistent with embodiments of the present disclosure. [Figure 7B]

[0015] FIG. 1 is a schematic diagram illustrating an exemplary electron beam system consistent with embodiments of the present disclosure. [Figure 7C]

[0016] FIG. 7C is a schematic diagram illustrating a top view of the example electron beam system of FIG. 7A or 7B, consistent with an embodiment of the present disclosure. [Figure 8A]

[0017] FIG. 1 is a schematic diagram illustrating an exemplary ACC module configuration, consistent with an embodiment of the present disclosure. [Figure 8B]

[0018] FIG. 8B is a schematic diagram illustrating a top view of the ACC module configuration of FIG. 8A, consistent with an embodiment of the present disclosure. [Figure 9]

[0019] 1 is a flowchart illustrating an exemplary process for testing a sample using an ACC module, consistent with embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009]

[0020] 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 numbers in different drawings represent the same or similar elements unless otherwise specified. The implementations described in the following description of exemplary embodiments do not represent all implementations consistent with the present disclosure. Instead, they are merely examples of apparatus and methods consistent with aspects related to the subject matter recited in the appended claims. For example, although some embodiments are described in the context of utilizing electron beams, the present disclosure is not limited thereto. Other types of charged particle beams may be similarly applied. Additionally, other imaging systems, such as optical imaging, light detection, x-ray detection, extreme ultraviolet inspection, and deep ultraviolet inspection, may be used.

[0010]

[0021] Electronic devices are built with circuits formed on a piece of silicon called a substrate. Many circuits can be formed together on the same piece of silicon and are called integrated circuits, or ICs. The size of these circuits is shrinking dramatically so that more and more circuits can fit on the substrate. For example, the IC chip in a smartphone may be about the size of a thumbnail, but may contain over 2 billion transistors, each less than 1 / 1000 the size of a human hair.

[0011]

[0022] The production of these tiny ICs is a complex, time-consuming, and expensive process, often involving hundreds of individual steps. An error in even one step can introduce defects into the finished IC, rendering it useless. Therefore, one of the goals of a manufacturing process is to avoid such defects and maximize the number of functional ICs produced by the process, thus increasing the overall yield of the process.

[0012]

[0023] One factor in improving yield is monitoring the chip manufacturing process to ensure it is producing a sufficient number of functional integrated circuits. One way to monitor the process is to inspect the chip's circuit structures at various stages of their formation. Inspection may be performed using a scanning electron microscope (SEM). The SEM can be used to image these very small structures, essentially taking a "picture" of the structures on the wafer. The image can also be used to determine whether the structures were formed properly and in the proper location. If the structures are defective, the process can be adjusted to make the defect less likely to occur again. Defects can occur at various stages of semiconductor processing. For the reasons stated above, it is important to find defects as quickly, accurately, and efficiently as possible.

[0013]

[0024] The operating principle of an SEM is similar to that of a camera. A camera takes a picture by receiving and recording the brightness and color of light reflected or emitted from a person or object. An SEM takes a "picture" by receiving and recording the energy or quantity of electrons reflected or emitted from a structure. Before taking such a "picture," an electron beam may be delivered to the structure. As electrons reflect or are emitted ("emitted") from the structure, the SEM's detector can receive and record the energy or quantity of those electrons to generate an image. Some SEMs use a single electron beam to take such a "picture" (called a "single-beam SEM"), while others use multiple electron beams to take multiple "pictures" of the wafer (called a "multi-beam SEM"). Using multiple electron beams allows the SEM to deliver more electron beams to the structure to obtain these multiple "pictures," resulting in more electrons being emitted from the structure. Thus, the detector can simultaneously receive more emitted electrons, producing images of the wafer's structures with greater efficiency and speed.

[0014]

[0025] When an electron beam is applied to a structure, a large beam current may cause charge to accumulate on the structure, which may affect the quality of the image. To adjust the accumulated charge on the structure, an ACC module may be used to irradiate a light beam, such as a laser beam, onto the structure to control the accumulated charge through effects such as photoconductive, photoelectric, or thermal effects.

[0015]

[0026] For example, semiconductor structures have outer atomic levels that exhibit an energy band structure including a valence band, an energy gap, and a conduction band. When external energy is applied to a semiconductor (for example, in the form of a light beam), valence electrons may gain enough energy to break their bond with their parent atoms and jump from the valence band to the conduction band. Free electrons in the conduction band are free to move due to their separation from their parent atoms. When an electron jumps from the valence band to the conduction band, a hole is created in the valence band. Thus, in semiconductors, when an electron jumps across the energy gap, a free electron-hole pair is created.

[0016]

[0027] The light beam impinging on the semiconductor can be adjusted to adjust the number of free electrons generated in the semiconductor (e.g., free electron density). The number of free electrons generated affects the current flow in the semiconductor. For example, increasing the number of free electrons generated in the semiconductor increases the current flow in the semiconductor and decreases the resistance in the semiconductor. Therefore, the light beam emitted from the ACC module can be used to control the charge on the semiconductor structure (e.g., improve the conductivity in a PN junction).

[0017]

[0028] However, ACC modules have limitations. While ACC modules are sometimes used to control the accumulated charge on a sample during inspection, these ACC modules do not necessarily simulate the operating conditions of the sample. For example, many IC failures are caused by high temperatures at PN junctions. ACC modules have some heating effects on the sample, but these heating effects are indistinguishable from photo-induced effects due to voltage contrast when the ACC module is used to directly emit a beam to heat pixels during inspection.

[0018]

[0029] Additionally, heating the sample stage is not suitable for in situ heating during inspection, as heating the stage can cause problems with mechanical metrology (e.g., the stage can drift due to temperature changes) or problems with the inspection signal for detecting the exact position on the sample (e.g., heating the stage can affect other components of the system, such as lenses, detectors, etc.).

[0019]

[0030] Some of the disclosed embodiments provide systems and methods that address some or all of these shortcomings by using one or more ACC modules to emit a light beam into an area adjacent to a pixel. The disclosed embodiments provide one or more ACC modules that can heat the pixel by emitting a light beam into an area adjacent to the pixel, thereby enabling detection of light-induced defects and thermally-induced defects using voltage contrast.

[0020]

[0031] The relative dimensions of components in the figures may be exaggerated for clarity. Within the following description of the figures, the same or similar reference numbers refer to the same or similar components or entities, and only the differences with respect to individual embodiments are described.

[0021]

[0032] As used herein, unless specifically stated otherwise, the term "or" includes all possible combinations unless impracticable. For example, if a component is described as being able to include A or B, then the component may include A, or B, or A and B, unless specifically stated otherwise or impracticable. As a second example, if a component is described as being able to include A, B, or C, then the component may include A, or B, or C, or A and B, or A and C, or B and C, or A, B, and C, unless specifically stated otherwise or impracticable.

[0022]

[0033] FIG. 1 illustrates an exemplary electron beam inspection (EBI) system 100 consistent with embodiments of the present disclosure. The EBI system 100 can be used for imaging. As shown in FIG. 1, the EBI system 100 includes a main chamber 101, a load / lock chamber 102, an electron beam tool 104, and a front-end equipment module (EFEM) 106. The electron beam tool 104 is disposed within the main chamber 101. The EFEM 106 includes a first loading port 106a and a second loading port 106b. The EFEM 106 may include one or more additional loading ports. The first loading port 106a and the second loading port 106b receive wafer front-opening unified pods (FOUPs) containing wafers (e.g., semiconductor wafers or wafers made of one or more other materials) or samples to be inspected (wafers and samples may be used interchangeably). A "lot" is a number of wafers that can be loaded for processing as a batch.

[0023]

[0034] One or more robot arms (not shown) of the EFEM 106 can transfer the wafer to the load / lock chamber 102. The load / lock chamber 102 is connected to a load / lock vacuum pumping system (not shown) that removes gas molecules from the load / lock chamber 102 to reach a first pressure that is less than atmospheric pressure. After the first pressure is reached, one or more robot arms (not shown) can transfer the wafer from the load / lock chamber 102 to the main chamber 101. The main chamber 101 is connected to a main chamber vacuum pumping system (not shown) that removes gas molecules from the main chamber 101 to reach a second pressure that is less than the first pressure. After the second pressure is reached, the wafer is subjected to inspection by the electron beam tool 104. The electron beam tool 104 can be a single beam system or a multi-beam system.

[0024]

[0035] The controller 109 is electronically connected to the electron beam tool 104. The controller 109 may be a computer configured to perform various controls of the EBI system 100. Although the controller 109 is shown in FIG. 1 as being external to the structure that includes the main chamber 101, the load / lock chamber 102, and the EFEM 106, it is understood that the controller 109 may be part of the structure.

[0025]

[0036] In some embodiments, the controller 109 may include one or more processors (not shown). A processor may be a general-purpose or specific electronic device capable of manipulating or processing information. For example, a processor may include any number of central processing units (or "CPUs"), graphics processing units (or "GPUs"), optical processors, programmable logic controllers, microcontrollers, microprocessors, digital signal processors, intellectual property (IP) cores, programmable logic arrays (PLAs), programmable array logic (PALs), generic array logic (GALs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), systems-on-chips (SoCs), application-specific integrated circuits (ASICs), and any combination of any type of circuitry capable of processing data. A processor may also be a virtual processor, including one or more processors distributed across multiple machines or devices coupled via a network.

[0026]

[0037] In some embodiments, the controller 109 may further include one or more memories (not shown). Memory may be a general-purpose or specialized electronic device capable of storing code and data accessible by a processor (e.g., via a bus). For example, memory may include any number of random access memories (RAMs), read-only memories (ROMs), optical disks, magnetic disks, hard drives, solid-state drives, flash drives, security digital (SD) cards, memory sticks, compact flash (CF) cards, or any combination of any type of storage device. Code may include an operating system (OS) and one or more application programs (or "apps") for specific tasks. Memory may also be virtual memory, including one or more memories distributed across multiple machines or devices coupled via a network.

[0027]

[0038] Reference is now made to FIG. 2, which is a schematic diagram illustrating an exemplary electron beam tool 104, including a multi-beam inspection tool that is part of the EBI system 100 of FIG. 1, consistent with embodiments of the present disclosure. In some embodiments, the electron beam tool 104 can be operated as a single-beam inspection tool that is part of the EBI system 100 of FIG. 1. The multi-beam electron beam tool 104 (also referred to herein as apparatus 104) includes an electron source 201, a Coulomb aperture plate (or "gun aperture plate") 271, a condenser lens 210, a source transformation unit 220, a primary projection system 230, a motorized stage 209, and a sample holder 207 supported by the motorized stage 209 for holding a sample 208 (e.g., a wafer or photomask) to be inspected. The multi-beam electron beam tool 104 may further include a secondary projection system 250 and an electron detection device 240. The primary projection system 230 may include an objective lens 231. The electronic detection device 240 may include a plurality of detection elements 241, 242, and 243. The beam separator 233 and the deflection scanning unit 232 may be located inside the primary projection system 230.

[0028]

[0039] The electron source 201, the Coulomb aperture plate 271, the condenser lens 210, the source conversion unit 220, the beam separator 233, the deflection scanning unit 232, and the primary projection system 230 may be aligned with a primary optical axis 204 of the apparatus 104. The secondary projection system 250 and the electron detection device 240 may be aligned with a secondary optical axis 251 of the apparatus 104.

[0029]

[0040] The electron source 201 may include a cathode (not shown) and an extractor or anode (not shown), and during operation, the electron source 201 is configured to emit primary electrons from the cathode, which are extracted or accelerated by the extractor and / or anode to form a primary electron beam 202 that forms a primary beam crossover (virtual or real) 203. The primary electron beam 202 may be visualized as emerging from the primary beam crossover 203.

[0030]

[0041] The source conversion unit 220 may include an image-forming element array (not shown), an aberration compensator array (not shown), a beam-limiting aperture array (not shown), and a pre-bending micro-deflector array (not shown). In some embodiments, the pre-bending micro-deflector array deflects multiple primary beamlets 211, 212, 213 of the primary electron beam 202 so that they perpendicularly enter the beam-limiting aperture array, the image-forming element array, and the aberration compensator array. In some embodiments, the apparatus 104 can be operated as a single-beam system such that a single primary beamlet is generated. In some embodiments, the condenser lens 210 is designed to focus the primary electron beam 202 into a parallel beam and perpendicularly incident on the source conversion unit 220. The imaging element array may include a plurality of micro-deflectors or micro-lenses, one for each of the primary beamlets 211, 212, and 213, for influencing the plurality of primary beamlets 211, 212, and 213 of the primary electron beam 202 and for forming a plurality of parallel images (virtual or real images) of the primary beam crossover 203. In some embodiments, the aberration compensator array may include a field curvature compensator array (not shown) and an astigmatism compensator array (not shown). The field curvature compensator array may include a plurality of micro-lenses for compensating for field curvature aberration of the primary beamlets 211, 212, and 213. The astigmatism compensator array may include a plurality of micro-astigmatism correctors for compensating for astigmatism of the primary beamlets 211, 212, and 213. The beam-limiting aperture array may be configured to limit the diameter of each of the primary beamlets 211, 212, and 213. 2 shows three primary beamlets 211, 212, and 213 by way of example, it being understood that the source conversion unit 220 can be configured to form any number of primary beamlets. The controller 109 can be connected to various parts of the EBI system 100 of FIG. 1, such as the source conversion unit 220, the electron detection device 240, the primary projection system 230, or the motorized stage 209. In some embodiments, the controller 109 can perform various image and signal processing functions, as described in more detail below.The controller 109 may also generate various control signals to control the operation of the charged particle beam inspection system.

[0031]

[0042] The condenser lens 210 is configured to focus the primary electron beam 202. The condenser lens 210 may be further configured to adjust the current of the primary beamlets 211, 212, and 213 at the down-beam of the source conversion unit 220 by varying the focusing power of the condenser lens 210. Alternatively, the current may be changed by changing the radial size of the beam-limiting aperture in the beam-limiting aperture array corresponding to each primary beamlet. The current may be changed by changing both the radial size of the beam-limiting aperture and the focusing power of the condenser lens 210. The condenser lens 210 may be an adjustable condenser lens configured such that the position of its first main surface is movable. The adjustable condenser lens may be configured to be magnetic, such that the off-axis beamlets 212 and 213 may illuminate the source conversion unit 220 with a rotation angle. The rotation angle varies depending on the focusing power or the position of the first main surface of the adjustable condenser lens. The collecting lens 210 may be an anti-rotation collecting lens that may be configured to maintain a constant rotation angle while changing the focusing power of the collecting lens 210. In some embodiments, the collecting lens 210 may be an adjustable anti-rotation collecting lens whose rotation angle does not change as its focusing power and the position of its first major surface change.

[0032]

[0043] The objective lens 231 may be configured to focus the beamlets 211, 212, and 213 onto the sample 208 for inspection, which in this embodiment may form three probe spots 221, 222, and 223 on the surface of the sample 208. The Coulomb aperture plate 271 is configured, in operation, to block peripheral electrons of the primary electron beam 202 to reduce the Coulomb effect, which may increase the size of the probe spots 221, 222, and 223 of the primary beamlets 211, 212, and 213, respectively, and result in poor inspection resolution.

[0033]

[0044] The beam separator 233 may be, for example, a Wien filter including electrostatic deflectors that generate electrostatic and magnetic dipole fields (not shown in FIG. 2 ). In operation, the beam separator 233 may be configured to exert an electrostatic force due to the electrostatic dipole field on individual electrons of the primary beamlets 211, 212, and 213. The electrostatic force is equal in magnitude but opposite in direction to the magnetic force that the magnetic dipole field of the beam separator 233 exerts on the individual electrons. Thus, the primary beamlets 211, 212, and 213 may pass at least substantially straight through the beam separator 233 with at least substantially zero deflection angle.

[0034]

[0045] The deflection scanning unit 232 is configured, in operation, to deflect the primary beamlets 211, 212, and 213 to scan the probe spots 221, 222, and 223 over respective scan areas on a section of the surface of the sample 208. In response to the incidence of the primary beamlets 211, 212, and 213 or the probe spots 221, 222, and 223 on the sample 208, electrons are generated from the sample 208, generating three secondary electron beams 261, 262, and 263. Each of the secondary electron beams 261, 262, and 263 typically includes secondary electrons (having an electron energy of 50 eV or less) and backscattered electrons (having an electron energy of 50 eV~ the landing energy of the primary beamlets 211, 212, and 213). The beam separator 233 is configured to deflect the secondary electron beams 261, 262, and 263 towards the secondary projection system 250. Secondary projection system 250 then focuses secondary electron beams 261, 262, and 263 onto detector elements 241, 242, and 243 of electron detection device 240. Detector elements 241, 242, and 243 are arranged to detect corresponding secondary electron beams 261, 262, and 263 and generate corresponding signals that are sent to controller 109 or a signal processing system (not shown), e.g., to construct an image of a corresponding scanned area of ​​sample 208.

[0035]

[0046] In some embodiments, detector elements 241, 242, and 243 detect corresponding secondary electron beams 261, 262, and 263, respectively, and generate corresponding intensity signal outputs (not shown) to an image processing system (e.g., controller 109). In some embodiments, each detector element 241, 242, and 243 may include one or more pixels. The intensity signal output of a detector element may be the sum of signals generated by all of the pixels in the detector element.

[0036]

[0047] In some embodiments, the controller 109 may include an image processing system including an image acquirer (not shown) and storage (not shown). The image acquirer may include one or more processors. For example, the image acquirer may include a computer, a server, a mainframe host, a terminal, a personal computer, any type of mobile computing device, etc., or a combination thereof. The image acquirer may be communicatively coupled to the electronic detection device 240 of the apparatus 104 via a medium such as an electrical conductor, a fiber optic cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, wireless radio, or a combination thereof, among others. In some embodiments, the image acquirer may receive signals from the electronic detection device 240 and construct an image. In this manner, the image acquirer may acquire an image of the sample 208. The image acquirer may also perform various post-processing functions, such as generating contours and overlaying indicators on the acquired image. The image acquirer may be configured to adjust the brightness and contrast of the acquired image, etc. In some embodiments, the storage may be a storage medium, such as a hard disk, a flash drive, cloud storage, random access memory (RAM), or other type of computer-readable memory. The storage may be coupled to the image acquirer and may be used to store the scanned raw image data as the original image and the post-processed image.

[0037]

[0048] In some embodiments, the image acquirer can acquire one or more images of the sample based on an imaging signal received from the electron detection device 240. The imaging signal can correspond to a scanning motion for performing charged particle imaging. The acquired image can be a single image including multiple imaging areas. The single image can be stored in storage. The single image can be an original image that can be divided into multiple regions. Each region can include one imaging area that includes a feature of the sample 208. The acquired image can include multiple images of a single imaging area of ​​the sample 208 sampled multiple times over a time sequence. The multiple images can be stored in storage. In some embodiments, the controller 109 can be configured to perform image processing steps using multiple images of the same location of the sample 208.

[0038]

[0049] In some embodiments, the controller 109 may include measurement circuitry (e.g., an analog-to-digital converter) to obtain a distribution of detected secondary electrons. The electron distribution data collected during the detection time window, in combination with the corresponding scan path data for each of the primary beamlets 211, 212, and 213 incident on the wafer surface, may be used to reconstruct an image of the wafer structure under inspection. The reconstructed image may be used to reveal various features of the internal or external structure of the sample 208, and thereby reveal defects that may be present in the wafer.

[0039]

[0050] In some embodiments, the controller 109 can control the motorized stage 209 to move the sample 208 during inspection of the sample 208. In some embodiments, the controller 109 can enable the motorized stage 209 to move the sample 208 in a direction continuously at a constant speed. In other embodiments, the controller 109 can enable the motorized stage 209 to change the speed of movement of the sample 208 over time depending on the step in the scanning process.

[0040]

[0051] 2 shows that apparatus 104 uses three primary electron beams, it is understood that apparatus 104 may use two or more primary electron beams. This disclosure does not limit the number of primary electron beams used in apparatus 104. In some embodiments, apparatus 104 may be an SEM used for lithography.

[0041]

[0052] Compared to a single charged particle beam imaging system ("single beam system"), a multiple charged particle beam imaging system ("multi-beam system") can be designed to optimize throughput for different scanning modes. Embodiments of the present disclosure provide a multi-beam system with the ability to optimize throughput for different scanning modes by using beam arrays with different geometries to accommodate different throughput and resolution requirements.

[0042]

[0053] Non-transitory computer-readable media may be provided that stores instructions for a processor (e.g., the processor of controller 109 in FIGS. 1-2) to perform image processing, data processing, beamlet scanning, database management, graphic display, operation of a charged particle beam instrument or another imaging device, etc. Common forms of non-transitory media include, for example, floppy disks, flexible disks, hard disks, solid state drives, magnetic tape or any other magnetic data storage medium, CD-ROMs, any other optical data storage medium, any physical medium with a pattern of holes, RAM, PROMs, and EPROMs, FLASH-EPROMs or any other flash memory, NVRAM, cache, registers, any other memory chip or cartridge, and networked versions thereof.

[0043]

[0054]

[0033] Figure 3 illustrates an electron beam system 300 consistent with an embodiment of the present disclosure. As shown in Figure 3, the electron beam system 300 includes an electron beam tool 310 (e.g., electron beam tool 104 of Figure 2, electron beam tool 710A of Figure 7A, or electron beam tool 710B of Figure 7B), an ACC module 320 (e.g., ACC modules 720A, 722A, 724A, or 726A of Figure 7A, ACC module 720B of Figure 7B, or ACC module configuration 800A of Figure 8A), and a wafer holder 330 (e.g., motorized stage 209 of Figure 2, wafer holder 730A of Figure 7A, or wafer holder 730B of Figure 7B) on which a sample to be inspected (e.g., sample 208 of Figure 2, wafer 740A of Figure 7A, or wafer 740B of Figure 7B) (e.g., wafer 340) is positioned. The electron beam tool 310 may emit a primary electron beam 312 (e.g., primary electron beam 202 of FIG. 2 , primary electron beam 712A of FIG. 7A , or primary electron beam 712B of FIG. 7B ) onto an area of ​​interest on the wafer 340 and collect secondary electrons emitted from the wafer surface to form an image of the area of ​​interest on the wafer 340. The ACC module 320 may include an ACC beam source that emits a light beam 322 (e.g., a laser beam, light beams 750A, 752A, 754A, or 756A of FIG. 7A , light beam 752B of FIG. 7B , or light beam 822 of FIG. 8A or 8B ) onto the wafer 340 and forms a beam spot 342 of the light beam 322 (e.g., area of ​​interest 742A of FIG. 7A , area of ​​interest 742B of FIG. 7B , beam spot 742C of FIG. 7C , or beam spot 842 of FIG. 8A or 8B ) on the wafer surface during inspection. When the primary electron beam 312 illuminates an area of ​​interest on the wafer 340, a large electron beam current may cause charge to accumulate. The light beam 322 emitted from the ACC module 320 may be configured to modulate the accumulated charge through, among other things, photoconduction or photoelectric effect, or a combination of photoconduction and photoelectric effect.

[0044]

[0055] In some embodiments, wafer 340 may include a PN junction diode (eg, PN junction diode 600 of FIG. 6) or bulk semiconductor material. In some embodiments, the ACC beam source may be a laser source.

[0045]

[0056] In some embodiments, the electron beam tool 310 can generate multiple primary electron beamlets to simultaneously scan multiple locations on the wafer 340. In some embodiments, the beam projected by the ACC module 320 can charge a location on the wafer 340 that is large enough to allow multiple primary electron beamlets to scan corresponding portions on the wafer 340. In some embodiments, the electron beam tool 310 can include multiple ACC modules 320 to project beams onto the wafer 340 for each primary electron beamlet, multiple primary electron beamlets, or any combination thereof.

[0046]

[0057] FIG. 4 shows an exemplary graph illustrating the yield rate of secondary electrons versus the landing energy of primary electron beamlets, consistent with an embodiment of the present disclosure. The graph illustrates the relationship between the landing energy of multiple beamlets of a primary electron beam (e.g., multiple beamlets 211, 212, or 213 of primary electron beam 202 in FIG. 2 , primary electron beam 312 in FIG. 3 , primary electron beam 712A in FIG. 7A , or primary electron beam 712B in FIG. 7B ) and the yield rate of a secondary electron beam (e.g., secondary electron beam 261, 262, or 263 in FIG. 2 ). The yield rate indicates the number of secondary electrons generated in response to the impact of a primary electron. For example, a yield rate greater than 1.0 indicates that more secondary electrons may be generated than the number of primary electrons that land on the wafer. Similarly, a yield rate less than 1.0 indicates that fewer secondary electrons may be generated in response to the impact of a primary electron.

[0047]

[0058] As shown in the graph of FIG. 4, when the landing energy of primary electrons is within the range of E1 to E2, more electrons may leave the wafer surface than land on it, which may result in a positive potential at the wafer surface. In some embodiments, defect inspection may be performed within the aforementioned landing energy range, referred to as a "positive mode." An electron beam tool (e.g., electron beam tool 104 of FIG. 2, electron beam tool 310 of FIG. 3, electron beam tool 710A of FIG. 7A, or electron beam tool 710B of FIG. 7B) may produce darker voltage-contrast images of device structures with a more positive surface potential because a detection device (e.g., detection device 240 of FIG. 2) may receive fewer secondary electrons (see FIG. 5).

[0048]

[0059] If the landing energy is lower than E1 or higher than E2, fewer electrons may leave the wafer's surface, resulting in a negative potential at the wafer's surface. In some embodiments, defect inspection may be performed within this range of landing energies, referred to as the "negative mode." An electron beam tool (e.g., electron beam tool 104 of FIG. 2) may produce brighter voltage-contrast images of device structures with more negative surface potentials, where a detection device (e.g., detection device 240 of FIG. 2) can receive more secondary electrons (see FIG. 5).

[0049]

[0060] When the primary electron beam illuminates an area of ​​interest on the wafer, a large electron beam current can cause charge accumulation. The light beam emitted from an ACC module (e.g., ACC module 320 of FIG. 3, ACC modules 720A, 722A, 724A, or 726A of FIG. 7A, ACC module 720B of FIG. 7B, or ACC module configuration 800A of FIG. 8A) can be configured to modulate the accumulated charge through, among other things, photoconduction or photoelectric effect, or a combination of photoconduction and photoelectric effect.

[0050]

[0061] In some embodiments, the landing energy of the primary electron beam may be controlled by the total bias between the electron source and the wafer.

[0051]

[0062] 5 shows a schematic diagram of the voltage contrast response of a wafer consistent with embodiments of the present disclosure. In some embodiments, physical and electrical defects in a wafer (e.g., resistive shorts and opens, deep trench capacitor defects, back-end-of-line (BEOL) defects, etc.) can be detected using voltage contrast methods in a charged particle inspection system. Defect detection using voltage contrast images may use one or more ACC modules (e.g., ACC module 320 of FIG. 3, ACC modules 720A, 722A, 724A, or 726A of FIG. 7A, ACC module 720B of FIG. 7B, or ACC module configuration 800A of FIG. 8A) in which one or more light beams (e.g., light beam 322 of FIG. 3, light beams 750A, 752A, 754A, or 756A of FIG. 7A, light beam 752B of FIG. 7B, or light beam 822 of FIG. 8A or FIG. 8B) are directed at an area of ​​a wafer being inspected (e.g., sample 208 of FIG. 2, wafer 340 of FIG. 3, wafer 740A of FIG. 7A, or wafer 740B of FIG. 7B).

[0052]

[0063] In some embodiments, defects in internal or external structures of a wafer can be detected using an electron beam tool (e.g., electron beam tool 104 of FIG. 2 , electron beam tool 310 of FIG. 3 , electron beam tool 710A of FIG. 7A , or electron beam tool 710B of FIG. 7B ) by illuminating the wafer with multiple beamlets of a primary electron beam (e.g., multiple beamlets 211, 212, or 213 of primary electron beam 202 of FIG. 2 , primary electron beam 312 of FIG. 3 , primary electron beam 712A of FIG. 7A , or primary electron beam 712B of FIG. 7B ) and measuring the voltage contrast response of the wafer to the illumination. In some embodiments, the wafer may include a test device area 520 developed on a substrate 510. In some embodiments, the test device area 520 may include multiple device structures 530 and 540 separated by an insulating material 550. For example, the device structure 530 is connected to the substrate 510. In contrast, the device structure 540 is separated from the substrate 510 by an insulating material 550 such that there is a thin insulator structure 570 (eg, a thin oxide) between the device structure 540 and the substrate 510 .

[0053]

[0064] The electron beam tool can generate secondary electrons (e.g., secondary electron beams 261, 262, or 263 in FIG. 2) from the surface of the test device area 520 by scanning multiple beamlets of the primary electron beam over the surface of the test device area 520. As explained above, when the landing energy of the primary electrons is between E1 and E2 (i.e., the yield rate is greater than 1.0 in FIG. 4), more electrons may leave the surface of the wafer than land on the surface of the wafer, thereby creating a positive potential at the surface of the wafer.

[0054]

[0065] 5, a positive potential may accumulate on the surface of the wafer. For example, after the electron beam tool scans the test device area 520 (e.g., during a pre-scan process), the device structure 540 may retain more positive charge because the device structure 540 is not connected to the electrical ground of the substrate 510, thereby creating a positive potential on the surface of the device structure 540. In contrast, primary electrons with the same landing energy (i.e., the same yield rate) imparted to the device structure 530 may retain less positive charge on the device structure 530 because the positive charge may be neutralized by electrons provided by the connection to the substrate 510. In some embodiments, the light beam emitted from the ACC module may be configured to modulate charge accumulation due to, among other things, photoconduction or the photoelectric effect, or a combination of the photoconduction and photoelectric effects.

[0055]

[0066] An image processing system (e.g., controller 109 of FIG. 2 ) of the electron beam tool may generate voltage-contrast images 535 and 545 of corresponding device structures 530 and 540, respectively. For example, device structure 530 may be shorted to ground and not retain an accumulated positive charge. Thus, when a primary electron beamlet lands on the surface of the wafer during inspection, device structure 530 may bounce back more secondary electrons, thereby resulting in a brighter voltage-contrast image. In contrast, because device structure 540 is not connected to substrate 510 or any other ground, device structure 540 may retain an accumulation of positive charge. This accumulation of positive charge may cause device structure 540 to bounce back fewer secondary electrons during inspection, thereby resulting in a darker voltage-contrast image.

[0056]

[0067] During inspection, dielectric breakdown or tunneling effects can change the accumulated surface potential level, thereby resulting in underdetection of defects. For example, when a high voltage is applied to a thin, highly resistive device structure (e.g., a thin oxide), such as insulator structure 570, leakage current can flow through the highly resistive structure, causing the structure to fail to function as a perfect insulator. This can affect circuit function and result in device failure. Similar leakage current effects can also occur in structures with improperly formed materials or highly resistive metal layers, such as a cobalt silicide (e.g., CoSi, CoSi2, Co2Si, Co3Si, etc.) layer between a tungsten plug and the source or drain area of ​​a field effect transistor (FET).

[0057]

[0068] 6 illustrates an exemplary PN junction diode 600 consistent with embodiments of the present disclosure. In some embodiments, a light beam (e.g., light beam 322 of FIG. 3 , light beam 750A, 752A, 754A, or 756A of FIG. 7A , light beam 752B of FIG. 7B , or light beam 822 of FIG. 8A or 8B ) emitted from an ACC module (e.g., ACC module 320 of FIG. 3 , ACC module 720A, 722A, 724A, or 726A of FIG. 7A , ACC module 720B of FIG. 7B , or ACC module configuration 800A of FIG. 8A ) and directed at the PN junction diode 600 can be adjusted to adjust the number of free electrons (e.g., free electron density) generated in the PN junction diode 600. As illustrated in FIG. 6 , the PN junction diode 600 includes a p-region 602, an n-region 604, and a PN junction 606. The PN junction diode 600 may be formed when a p-type semiconductor (e.g., p region 602) is fused to an n-type semiconductor (e.g., n region 604), which may create a potential barrier voltage across the PN junction 606. The p region 602 may contain positively charged holes 612, and the n region 604 may contain negatively charged electrons 614. The PN junction 606 may not contain any charge carriers (e.g., the PN junction 606 may be a depletion region). In some embodiments, the current flow and resistance of the PN junction diode 600 may vary depending on the number of free electrons generated in the PN junction diode 600. Therefore, a light beam emitted from the ACC module may be used to control the charge of the PN junction diode 600.

[0058]

[0069] A semiconductor structure has outer atomic levels that exhibit an energy band structure including a valence band, an energy gap, and a conduction band. When external energy (e.g., light beam 322 in FIG. 3 , light beams 750A, 752A, 754A, or 756A in FIG. 7A , light beam 752B in FIG. 7B , or light beam 822 in FIG. 8A or 8B ) is applied to a semiconductor, valence electrons (e.g., electron 614) gain enough energy to break their bonds with their parent atoms and jump across a depletion layer (e.g., PN junction 606) from the valence band (e.g., n region 604) to the conduction band (e.g., p region 602). Free electrons in the conduction band are free to move due to their separation from their parent atoms. When an electron jumps from the valence band to the conduction band, a hole (e.g., hole 612) is created in the valence band. Thus, in a semiconductor, free electron-hole pairs are created when an electron jumps across an energy gap, thereby generating a current through the PN junction diode 600. In some cases, temperature variations cause variations in the vibration of atoms within the semiconductor, which in turn causes changes in the flow of electrical current within the semiconductor.

[0059]

[0070] During operation, physical changes in the device may result in the application of a negative voltage (e.g., reverse bias) to the PN junction diode 600, which may result in free charges leaving the PN junction 606, thereby widening the PN junction 606. The increase in the width of the PN junction 606 may result in an increase or decrease in the effective resistance of the PN junction 606, which may allow or block the flow of current through the PN junction 606. In some cases, the increase in the reverse bias voltage applied to the PN junction diode 600 may cause the PN junction 606 to overheat and fail due to an avalanche effect around the PN junction 606.

[0060]

[0071] The diode current I of the PN junction 606 d can be expressed by the following equation (1):

number

[0061]

[0072] Similarly, in bulk semiconductor materials, the photocurrent I ph can be expressed by the following equation (3): I ph =qns(μ n +μ p )V / L (3) where q is the charge, n is the photon-generated carrier density, s is the cross-sectional area, V is the applied voltage, L is the length, and μ n is the electron mobility, and μp is the mobility of holes in the bulk semiconductor material. n and hole mobility μ p can be expressed by the following equation (4), respectively.

number

[0062]

[0073] As can be seen from equations (3) and (4), the photocurrent I of a bulk semiconductor material ph can vary with temperature or variations in the density of photon-generated carriers. For example, when a beam of light is emitted into a bulk semiconductor material, the photocurrent I of the bulk semiconductor material ph During testing, the ACC module typically operates at low power, resulting in a large photocurrent I in the bulk semiconductor material. ph It can be shown that changes in n are often due to changes in n rather than changes in T. That is, ACC modules operating at low power typically generate charge through photons rather than thermal conduction.

[0063]

[0074] The light beam emitted from the ACC module and directed onto the semiconductor can be adjusted to adjust the number of free electrons (e.g., free electron density) generated in the semiconductor. As shown in equations (1)-(4) above (e.g., see charge amount generated, charge amount, hole or electron diffusion length, photon-generated carrier density, and hole or electron mobility), the number of free electrons generated affects the current flow in the semiconductor. For example, as the number of free electrons generated in the semiconductor increases, the current flow in the semiconductor increases and the resistance in the semiconductor decreases. Therefore, the light beam emitted from the ACC module can be used to control the charge on the semiconductor structure (e.g., improve conductivity in a PN junction).

[0064]

[0075] The ACC module can charge the wafer with a desired luminous energy during inspection by providing a light beam with a higher luminous energy to the wafer so that a higher power density is provided to the wafer, thereby achieving a higher processing speed during wafer inspection operations, thereby achieving a lower magnification, thereby allowing a beam with a sufficiently high beam density and luminous energy to reach the wafer.

[0065]

[0076] While ACC modules are sometimes used to control the accumulated charge on a sample during testing, these ACC modules do not necessarily simulate the operating conditions of the sample. For example, many IC failures are caused by high temperatures at PN junctions. While ACC modules have some heating effects on the sample, these heating effects are indistinguishable from photoinduced effects due to voltage contrast when the ACC module is used to emit a beam directly at pixels to heat them during testing. Because the effective resistance and voltage of a material change with current, the voltage contrast of the sample can change in response to changes in the amount of charge generated. However, because the sample current can change due to photon-induced or thermal effects, when the ACC module emits a beam directly at pixels to heat them during testing, the voltage contrast variation due to photon-induced effects may be indistinguishable from the voltage contrast variation due to thermal effects. For example, changes in the generation of free electrons caused by the applied light beam or temperature changes can cause different variations in the effective resistance and voltage of a material.

[0066]

[0077] Because heating of the sample stage can cause problems with mechanical metrology (e.g., the stage can drift due to temperature changes) or problems with inspection signals for detecting precise positions on the sample (e.g., heating of the stage can affect other components of the system, such as lenses, detectors, etc.), a system and method may be needed that uses one or more ACC modules to indirectly heat areas of the sample, thereby enabling detection of light-induced and thermally-induced defects using voltage contrast.

[0067]

[0078] 7A and 7B show electron beam systems 700A and 700B, respectively, consistent with embodiments of the present disclosure. FIG. 7C is a top view 700C of electron beam system 700A or 700B in operation for wafer inspection, consistent with embodiments of the present disclosure. As shown in FIG. 7A, electron beam system 700A includes an electron beam tool 710A (e.g., electron beam tool 104 of FIG. 2 or electron beam tool 310 of FIG. 3), a wafer holder 730A (e.g., motorized stage 209 of FIG. 2 or wafer holder 330 of FIG. 3) on which a sample to be inspected (e.g., sample 208 of FIG. 2 or wafer 340 of FIG. 3) (e.g., wafer 740A) is positioned, and ACC modules 720A, 722A, 724A, and 726A (e.g., ACC module 320 of FIG. 3). The electron beam tool 710A may emit a primary electron beam 712A (e.g., primary electron beam 202 in FIG. 2 or primary electron beam 312 in FIG. 3) at an area of ​​interest 742A (e.g., beam spot 342 in FIG. 3) on the wafer 740A and collect secondary electrons emitted from the wafer surface to form an image of the area of ​​interest on the wafer 740A. The ACC modules 720A, 722A, 724A, and 726A may include ACC beam sources that emit light beams 750A, 752A, 754A, and 756A (e.g., laser beam or light beam 322 in FIG. 3), respectively, onto the wafer 740A during inspection.

[0068]

[0079] 7A shows four ACC modules, electron beam system 700A may include any number of ACC modules. Similarly, each light beam 750A, 752A, 754A, or 756A may include multiple light beams. In some embodiments, electron beam system 700A may include one ACC module that includes one or more ACC beam sources.

[0069]

[0080] In some embodiments, the electron beam tool 710A can generate multiple primary electron beamlets to simultaneously scan multiple locations on the wafer 740A. In some embodiments, the beams projected by the ACC modules 720A, 722A, 724A, and 726A can charge locations on the wafer 740A that are large enough to allow multiple primary electron beamlets to scan corresponding portions on the wafer 740A. In some embodiments, the ACC modules 720A, 722A, 724A, and 726A can project beams onto the wafer 740A for each primary electron beamlet, multiple primary electron beamlets, or any combination thereof.

[0070]

[0081] 7B, electron beam system 700B includes an electron beam tool 710B (e.g., electron beam tool 104 of FIG. 2 or electron beam tool 310 of FIG. 3), a wafer holder 730B (e.g., motorized stage 209 of FIG. 2 or wafer holder 330 of FIG. 3) on which a sample to be inspected (e.g., sample 208 of FIG. 2 or wafer 340 of FIG. 3) (e.g., wafer 740B) is positioned, and an ACC module 720B (e.g., ACC module 320 of FIG. 3). Electron beam tool 710B can emit a primary electron beam 712B onto an area of ​​interest 742B (e.g., beam spot 342 of FIG. 3) on wafer 740B and collect secondary electrons emitted from the wafer surface to form an image of the area of ​​interest on wafer 740B. The ACC module 720B may include an ACC beam source that emits a light beam 752B (eg, laser beam or light beam 322 in FIG. 3) during inspection.

[0071]

[0082] Electron beam system 700B may include beam splitters 762B and mirrors 772B. In some embodiments, beam splitters 762B may each be configured to split an emitted beam, and mirrors 772B may each be configured to reflect a light beam. For example, beam splitter 762B may be configured to split light beam 752B into multiple light beams, and mirror 772B may be configured to reflect the multiple light beams 752B such that four light beams 752B are directed onto wafer 740B during inspection.

[0072]

[0083] Although one ACC module is shown in Figure 7B, electron beam system 700B may include any number of ACC modules. Similarly, electron beam system 700B may include any number of beam splitters 762B or mirrors 772B so that any number of light beams 752B can be directed onto wafer 740B during inspection. In some embodiments, beam splitters 762B or mirrors 772B may be included in ACC module 720B.

[0073]

[0084] In some embodiments, the electron beam tool 710B can generate multiple primary electron beamlets to simultaneously scan multiple locations on the wafer 740B. In some embodiments, the beam projected by the ACC module 720B can charge a location on the wafer 740B that is large enough so that multiple primary electron beamlets can scan corresponding portions on the wafer 740B. In some embodiments, the ACC module 720B can project a beam onto the wafer 740B for each primary electron beamlet, multiple primary electron beamlets, or any combination thereof.

[0074]

[0085] As shown in FIG. 7C , a top view 700C of electron beam system 700A or 700B may include a beam spot 742C (e.g., beam spot 342 in FIG. 3 , area of ​​interest 742A in FIG. 7A , or area of ​​interest 742B in FIG. 7B ) emitted from one or more ACC modules (e.g., ACC module 320 in FIG. 3 , ACC modules 720A, 722A, 724A, or 726A in FIG. 7A , or ACC module 720B in FIG. 7B ) and a pixel 780C within the field of view (FOV) of electron beam tool 710A or 710B. In some embodiments, pixel 780C may include multiple pixels. For ease of illustration, electron beam tool 710A or 710B (e.g., electron beam tool 104 in FIG. 2 or electron beam tool 310 in FIG. 3 ) has been omitted from FIG. 7C . In some embodiments, a specially designed sample surface may be used to collect one or more light beam signals emitted from ACC modules 720A, 722A, 724A, or 726A of Figure 7A or ACC module 720B of Figure 7B (e.g., ACC module 320 of Figure 3). In still other embodiments, a wafer surface or a smooth surface may be used to collect one or more light beam signals emitted from ACC modules 720A, 722A, 724A, or 726A of Figure 7A or ACC module 720B of Figure 7B.

[0075]

[0086] In some embodiments, beam spots 742C emitted from one or more ACC modules may illuminate an area on the wafer adjacent to pixel 780C. In some embodiments, this area may include multiple areas, or a pixel may include multiple pixels. Beam spots 742C may indirectly heat pixel 780C such that beam spots 742C do not cause photo-induced carrier density changes in pixel 780C. For example, thermal energy 790C may be diffused from each beam spot 742C to pixel 780C without beam spots 742C directly exposing pixel 780C to any photons from beam spots 742C, thereby mitigating any source or cause of direct photon-induced effects in pixel 780C. In some embodiments, mitigating the source of direct photon-induced effects at pixel 780C may include generating substantially zero photon-induced charge at pixel 780C or causing substantially zero photon-induced carrier density change at pixel 780C because beam spot 742C may not illuminate pixel 780C but only an area adjacent to pixel 780C. In some embodiments, mitigating the source of direct photon-induced effects at pixel 780C may include minimizing or reducing the impact of the source of direct photon-induced effects at pixel 780C. In some embodiments, one or more separate laser sources (e.g., from one or more ACC modules) may be configured to adjust surface charges on the wafer to control accumulated charge on the wafer during inspection.

[0076]

[0087] In some embodiments, the ACC beam source may be a laser (e.g., an infrared laser, a visible laser, an ultraviolet laser, a multi-laser configuration, etc.). For example, the ACC beam source may include a laser having a wavelength smaller than the energy bandgap of the target material to generate heat in the material. When the laser has a wavelength smaller than the energy bandgap of the target material, the photons of the laser have more energy than the energy bandgap, thereby exciting electrons in the target material to generate heat in the target material.

[0077]

[0088] In some embodiments, the thermal diffusion caused by beam spot 742C can cause pixel 780C to reach the temperature of an operating device (e.g., 40-100°C) that includes pixel 780C, thereby advantageously simulating wafer operating conditions. Thermal diffusion can induce defects in pixel 780C. In some embodiments, the defects can include multiple defects. In some embodiments, electron beam system 700A or 700B can be configured to detect one or more defects in pixel 780C using voltage contrast. Because pixel 780C is not directly exposed to beam spot 742C, voltage contrast can be used to distinguish photon-induced defects from thermally induced defects during inspection. For example, variations in the effective resistance and voltage of a material due to photon-induced changes in the generation of free electrons can be distinguished from thermally induced changes in the generation of free electrons.

[0078]

[0089] In some embodiments, when the ACC beam source includes a laser (e.g., an infrared laser) having a wavelength smaller than the energy bandgap of the target material, the ACC beam source emits a beam spot directly on the pixel, thereby generating heat in the material while mitigating any source or cause of direct photon-induced defects, photo-induced carrier density changes, or photoelectric effects in the pixel.

[0079]

[0090] In some embodiments, such as those shown in Figures 7A, 7B, or 7C, the ACC module 720A, 722A, 724A, or 726A, ACC module 720B, is located outside the vacuum chamber in which the electron beam tool 710A or 710B and wafer 740A or 740B are located. During operation of the electron beam system 700A, 700B, or 700C, the light beam 750A, 752A, 754A, 756A, or 752B may pass through one or more windows formed in the vacuum chamber. In some alternative embodiments, the ACC module 720A, 722A, 724A, 726A, or 720B may be located inside the vacuum chamber.

[0080]

[0091] 8A is an exemplary ACC module configuration 800A consistent with an embodiment of the present disclosure. FIG. 8B is a top view 800B of an electron beam system including the ACC module configuration 800A (e.g., ACC module 320 of FIG. 3) in operation for wafer inspection consistent with an embodiment of the present disclosure.

[0081]

[0092] As shown in FIG. 8A , ACC module configuration 800A may include ACC beam source 824 and parabolic mirrors 872 and 874. ACC beam source may emit multiple light beams 822. Parabolic mirror 872 may be configured to reflect each light beam 822 to parabolic mirror 874. Parabolic mirror 874 may be configured to receive each light beam 822 (e.g., light beam 322 in FIG. 3 ) and reflect each light beam 822 to an area adjacent to a pixel on a wafer (e.g., sample 208 in FIG. 2 or wafer 340 in FIG. 3 ). ACC module configuration 800A may include any number of ACC beam sources or parabolic mirrors. In some embodiments, the area may include multiple areas, or the pixel may include multiple pixels.

[0082]

[0093] As shown in FIG. 8B , a top view 800B of an electron beam system including an ACC module configuration 800A may include a beam spot 842 emitted from one or more ACC beam sources 824 and a pixel 880 within the FOV of an electron beam tool (e.g., electron beam tool 104 in FIG. 2 or electron beam tool 310 in FIG. 3 ). In some embodiments, the beam spot 842 (e.g., beam spot 342 in FIG. 3 ) may be a ring shape formed by the light beam 822. In some embodiments, the beam spot 842 may surround the pixel 880. In some embodiments, the pixel 880 may include multiple pixels. For simplicity of illustration, the electron beam tool is omitted from FIG. 8B . In some embodiments, a specially designed sample surface may be used to collect one or more light beam signals emitted from the ACC beam source 824. In still other embodiments, a wafer surface or a smooth surface may be used to collect one or more light beam signals emitted from the ACC beam source 824.

[0083]

[0094] In some embodiments, beam spot 842 formed by light beam 822 may illuminate an area adjacent pixel 880 on the wafer. Beam spot 842 may indirectly heat pixel 880 such that beam spot 842 does not cause a photo-induced carrier density change at pixel 880. For example, thermal energy 890 may be diffused from beam spot 842 to pixel 880 without beam spot 842 directly exposing pixel 880 to any photons from beam spot 842, thereby mitigating, reducing, or minimizing any source or cause of direct photon-induced effects at pixel 880. In some embodiments, mitigating the cause of direct photon-induced effects at pixel 880 may include generating substantially zero photon-induced charge at pixel 880 or causing substantially zero photon-induced carrier density change at pixel 880 because beam spot 842 may illuminate only an area adjacent pixel 880 rather than illuminating pixel 880. In some embodiments, mitigating the source of direct photon-induced effects at pixel 880 may include minimizing or reducing the impact of the source of direct photon-induced effects at pixel 880. In some embodiments, one or more separate laser sources (e.g., from one or more ACC modules) may be configured to condition surface charges on the wafer to control accumulated charge on the wafer during inspection.

[0084]

[0095] In some embodiments, the ACC beam source 824 may be a laser (e.g., an infrared laser, a visible laser, an ultraviolet laser, a multi-laser configuration, etc.). For example, the ACC beam source 824 may include a laser having a wavelength smaller than the energy bandgap of the target material to generate heat in the material. When a laser has a wavelength smaller than the energy bandgap of the target material, the photons of the laser have more energy than the energy bandgap, thereby causing a photon to excite electrons in the target material such that heat is generated in the target material.

[0085]

[0096] In some embodiments, the thermal diffusion caused by beam spot 842 can cause pixel 880 to reach the temperature of an operating device containing pixel 880 (e.g., 40-100°C), thereby advantageously simulating wafer operating conditions. In some embodiments, the thermal diffusion can induce defects in pixel 880. In some embodiments, the defects can include multiple defects. In some embodiments, the electron beam system can be configured to detect one or more defects in pixel 880 using voltage contrast. Because pixel 880 is not directly exposed to beam spot 842, voltage contrast can be used to distinguish photon-induced defects from thermally induced defects during inspection. For example, variations in the effective resistance and voltage of a material due to photon-induced changes in the generation of free electrons can be distinguished from thermally induced changes in the generation of free electrons.

[0086]

[0097] In some embodiments, when the ACC beam source includes a laser (e.g., an infrared laser) having a wavelength smaller than the energy bandgap of the target material, the ACC beam source can emit a beam spot directly on the pixel, thereby generating heat in the material while mitigating any source or cause of direct photon-induced defects, photo-induced carrier density changes, or photoelectric effects in the pixel.

[0087]

[0098] Reference is now made to FIG. 9, which is a flowchart illustrating an exemplary process 900 for testing a sample using an ACC module, consistent with embodiments of the present disclosure.

[0088]

[0099] In step 901, a module including a laser source (e.g., ACC module 320 of FIG. 3 , ACC modules 720A, 722A, 724A, or 726A of FIG. 7A , ACC module 720B of FIG. 7B , or ACC module configuration 800A of FIG. 8A ) may emit a beam (e.g., light beam 322 of FIG. 3 , light beams 750A, 752A, 754A, or 756A of FIG. 7A , light beam 752B of FIG. 7B , or light beam 822 of FIG. 8A or 8B ). An ACC module may include one or more ACC beam sources, each emitting one or more light beams at a wafer during inspection. In some embodiments, an electron beam system may include one ACC module including one or more ACC beam sources. An electron beam tool (e.g., electron beam tool 104 of FIG. 2, electron beam tool 310 of FIG. 3, electron beam tool 710A of FIG. 7A, or electron beam tool 710B of FIG. 7B) may emit a primary electron beam (e.g., primary electron beam 202 of FIG. 2, primary electron beam 312 of FIG. 3, primary electron beam 712A of FIG. 7A, or primary electron beam 712B of FIG. 7B) onto an area of ​​interest on a wafer (e.g., sample 208 of FIG. 2, wafer 340 of FIG. 3, wafer 740A of FIG. 7A, or wafer 740B of FIG. 7B) and collect secondary electrons (e.g., secondary electron beams 261, 262, or 263 of FIG. 2) emitted from the wafer surface to form an image of the area of ​​interest on wafer 740A.

[0089]

[0100] In some embodiments, the electron beam system may include a beam splitter (e.g., beam splitter 762B in FIG. 7B) and a mirror (e.g., mirror 772B in FIG. 7B). In some embodiments, the beam splitters may each be configured to split the emitted beam, and each mirror may be configured to reflect a light beam. For example, the beam splitter may be configured to split the light beam into multiple light beams, and the mirror may be configured to reflect the multiple light beams so that the multiple light beams can be directed onto the wafer during inspection.

[0090]

[0101] In some embodiments, an ACC module configuration (e.g., ACC module configuration 800A of FIG. 8A or 8B) may include an ACC beam source (e.g., ACC beam source 824 of FIG. 8A or 8B) and a parabolic mirror (e.g., parabolic mirrors 872 and 874 of FIG. 8A or 8B). The ACC beam source may emit multiple light beams (e.g., multiple light beams 822 of FIG. 8A or 8B). The first parabolic mirror may be configured to reflect each light beam to a second parabolic mirror. The second parabolic mirror may be configured to receive each light beam and reflect each light beam to an area adjacent to a pixel (e.g., pixel 880 of FIG. 8A or 8B) on a wafer (e.g., sample 208 of FIG. 2 or wafer 340 of FIG. 3). The ACC module configuration may include any number of ACC beam sources or parabolic mirrors. In some embodiments, the area may include multiple areas, or the pixel may include multiple pixels.

[0091]

[0102] In some embodiments, the ACC module configuration may include a beam spot (e.g., beam spot 842 in FIG. 8B ) emitted from one or more ACC beam sources, and the beam spot may be a ring shape formed by the emitted light beams. In some embodiments, the beam spot may surround a pixel (e.g., pixel 880 in FIG. 8B ). In some embodiments, a pixel may include multiple pixels. In some embodiments, a specially designed sample surface may be used to collect one or more light beam signals emitted from the ACC beam source. In yet other embodiments, a wafer surface or a smooth surface may be used to collect one or more light beam signals emitted from the ACC beam source.

[0092]

[0103] In step 903, the light beam can illuminate an area on the wafer adjacent to the pixel to indirectly heat the pixel and thereby reduce the source of direct photon-induced effects at the pixel.

[0093]

[0104] In some embodiments, a beam spot emitted from one or more ACC modules (e.g., beam spot 342 in FIG. 3 , area of ​​interest 742A in FIG. 7A , area of ​​interest 742B in FIG. 7B , beam spot 742C in FIG. 7C , or beam spot 842 in FIG. 8A or 8B ) may illuminate an area on the wafer adjacent to a pixel (e.g., pixel 780C in FIG. 7C or pixel 880 in FIG. 8A or 8B ). In some embodiments, this area may include multiple areas, or a pixel may include multiple pixels. The beam spot may indirectly heat the pixel such that the beam spot does not cause photo-induced carrier density changes at the pixel. For example, thermal energy (e.g., thermal energy 790C in FIG. 7C or thermal energy 890 in FIG. 8B ) may be diffused from each beam spot to the pixel without directly exposing the pixel to any photons from the beam spot, thereby mitigating any source or cause of direct photon-induced effects at the pixel. In some embodiments, mitigating the source of direct photon-induced effects at the pixel may include generating substantially zero photon-induced charge at the pixel or causing substantially zero photon-induced carrier density change at the pixel because the beam spot may not illuminate the pixel but only an area adjacent to the pixel. In some embodiments, mitigating the source of direct photon-induced effects at the pixel may include minimizing or reducing the impact of the source of direct photon-induced effects at the pixel. In some embodiments, one or more separate laser sources (e.g., from one or more ACC modules) may be configured to adjust surface charges on the wafer to control accumulated charge on the wafer during inspection.

[0094]

[0105] In some embodiments, the ACC beam source may be a laser (e.g., an infrared laser, a visible laser, an ultraviolet laser, a multi-laser configuration, etc.). For example, the ACC beam source may include a laser having a wavelength smaller than the energy bandgap of the target material to generate heat in the material. When the laser has a wavelength smaller than the energy bandgap of the target material, the photons of the laser have more energy than the energy bandgap, thereby exciting electrons in the target material to generate heat in the target material.

[0095]

[0106] In some embodiments, when the ACC beam source includes a laser (e.g., an infrared laser) having a wavelength smaller than the energy bandgap of the target material, the ACC beam source can emit a beam spot directly on the pixel, thereby generating heat in the material while mitigating any source or cause of direct photon-induced defects, photo-induced carrier density changes, or photoelectric effects in the pixel.

[0096]

[0107] In step 905, the electron beam tool can detect defects in the pixels, the defects being induced by indirect heating of the pixels.

[0097]

[0108] In some embodiments, the thermal diffusion caused by the beam spot can cause the pixel to reach the temperature of an operating device containing the pixel (e.g., 40-100°C), thereby advantageously simulating wafer operating conditions. In some embodiments, the thermal diffusion can induce defects in the pixel. In some embodiments, the defects can include multiple defects. In some embodiments, the electron beam system can be configured to detect one or more defects in the pixel using voltage contrast. Because the pixel is not directly exposed to the beam spot, voltage contrast can be used to distinguish photon-induced defects from thermally induced defects during inspection. For example, variations in the effective resistance and voltage of a material due to photon-induced changes in the generation of free electrons can be distinguished from thermally induced changes in the generation of free electrons.

[0098]

[0109] A non-transitory computer-readable medium may be provided that stores instructions for a processor of a controller (e.g., controller 109 in FIG. 1 ) for controlling an ACC module consistent with embodiments of the present disclosure based on the beam profile and beam power of the light beam. For example, based on the beam power of the light beam, the controller may automatically adjust the current used by an ACC beam source included in the ACC module to maintain the output power of the ACC beam source at a target power or in a stable state. Furthermore, based on the beam power of the light beam, the controller may be configured to monitor the position on the wafer surface of a beam spot formed by the light beam. Common forms of non-transitory media include, for example, floppy disks, flexible disks, hard disks, solid state drives, magnetic tape or any other magnetic data storage medium, compact disk read-only memory (CD-ROM), any other optical data storage medium, any physical medium with a pattern of holes, random access memory (RAM), programmable read-only memory (PROM), and erasable programmable read-only memory (EPROM), FLASH-EPROM or any other flash memory, non-volatile random access memory (NVRAM), cache, registers, any other memory chip or cartridge, and networked versions thereof.

[0099]

[0110] The embodiments can be further described using the following clauses. 1. An electron beam system comprising: a module configured to emit a beam that illuminates an area on the wafer adjacent to the pixel to indirectly heat the pixel and thereby mitigate the source of direct photon-induced effects at the pixel; an electron beam tool configured to detect defects in the pixels, the defects being induced by indirect heating of the pixels; and Including, the system. 2. The system of claim 1, wherein the electron beam tool is further configured to detect defects using voltage contrast. 3. A system as described in any one of clauses 1-2, wherein the module includes a laser source. 4. The beam comprises a plurality of beams; the laser source includes a plurality of laser sources; and 4. The system of claim 3, wherein each laser source of the plurality of laser sources is configured to emit one beam of the plurality of beams. 5. The system of clause 4, wherein the area includes a plurality of areas, and each beam of the plurality of beams illuminates each area of ​​the plurality of areas adjacent to a pixel on the wafer. 6. The system of clause 5, wherein each beam of the plurality of beams indirectly heats a pixel. 7. A system according to any one of clauses 1-2, wherein the module further comprises a beam splitter and a mirror. 8. The system of clause 7, wherein the beam splitter is configured to split the beam into multiple beams. 9. The system of clause 8, wherein the area includes a plurality of areas, and the mirror is configured to reflect each beam of the plurality of beams to each area of ​​the plurality of areas. 10. The system of clause 9, wherein each beam of the plurality of beams illuminates each area of ​​a plurality of areas adjacent to a pixel on the wafer. 11. The system of clause 10, wherein each beam of the plurality of beams indirectly heats a pixel. 12. The system of claim 11, wherein the beam splitter comprises a plurality of beam splitters. 13. The system of any one of clauses 11-12, wherein the mirror comprises a plurality of mirrors. 14. A system as described in any one of clauses 1-2, wherein the beam comprises a plurality of beams. 15. The system of clause 14, wherein the module further comprises a first parabolic mirror and a second parabolic mirror. 16. The system of clause 15, wherein the first parabolic mirror is configured to reflect each beam of the plurality of beams to the second parabolic mirror. 17. An area includes multiple areas; a second parabolic mirror configured to receive each beam of the plurality of beams; and 17. The system of clause 16, wherein a second parabolic mirror is configured to reflect each beam of the plurality of beams onto a respective area of ​​a plurality of areas adjacent to a pixel on the wafer. 18. The system of clause 17, wherein each beam of the plurality of beams indirectly heats a pixel. 19. The system of clause 18, wherein the multiple beams form a ring shape surrounding the pixel. 20. The system of any one of clauses 1 to 19, wherein the pixel comprises a plurality of pixels. 21. The system of any one of clauses 1 to 20, wherein the defect includes multiple defects. 22. The system of any one of clauses 3 to 21, wherein the laser source comprises one of an infrared laser, a visible laser, or an ultraviolet laser. 23. The laser source includes a plurality of laser sources; and 23. The system of any one of clauses 3 or 22, wherein at least one laser source of the plurality of laser sources is configured to adjust a plurality of surface charges on the wafer. 24. A system according to any one of clauses 1 to 23, wherein the temperature of the pixel reaches the operating temperature of the pixel by indirect heating. 25. The system of any one of clauses 1 to 24, wherein the pixel comprises a PN junction. 26. The system of any one of clauses 1-24, wherein the pixel comprises a bulk material. 27. Emitting a beam from the module that illuminates an area adjacent to the pixel on the wafer to indirectly heat the pixel, thereby mitigating the source of direct photon-induced effects at the pixel; and Detecting defects in the pixel, the defects being induced by indirect heating of the pixel; 12. A testing method comprising: 28. The method of clause 27, further comprising detecting defects using voltage contrast. 29. The method of any one of clauses 27-28, wherein the module includes a laser source. 30. The beam comprises a plurality of beams, and the laser source comprises a plurality of laser sources; 30. The method of clause 29, further comprising emitting one beam of the plurality of beams from each laser source of the plurality of laser sources. 31. The method of clause 30, wherein the area comprises a plurality of areas, and each beam of the plurality of beams illuminates each area of ​​the plurality of areas adjacent to a pixel on the wafer. 32. The method of clause 31, wherein each beam of the plurality of beams indirectly heats a pixel. 33. The method of any one of clauses 27-28, wherein the module further comprises a beam splitter and a mirror. 34. The method of clause 33, wherein the beam splitter is configured to split the beam into multiple beams. 35. The method of clause 34, wherein the area comprises a plurality of areas, and the mirror is configured to reflect each beam of the plurality of beams to each area of ​​the plurality of areas. 36. The method of clause 35, wherein each beam of the plurality of beams illuminates each area of ​​a plurality of areas adjacent to a pixel on the wafer. 37. The method of clause 36, wherein each beam of the plurality of beams indirectly heats a pixel. 38. The method of clause 37, wherein the beam splitter comprises a plurality of beam splitters. 39. The method of any one of clauses 37-38, wherein the mirror comprises a plurality of mirrors. 40. The method of any one of clauses 27-28, wherein the beam comprises a plurality of beams. 41. The method of clause 40, wherein the module further comprises a first parabolic mirror and a second parabolic mirror. 42. The method of clause 41, wherein a first parabolic mirror is configured to reflect each beam of the plurality of beams to a second parabolic mirror. 43. An area contains multiple areas; a second parabolic mirror configured to receive each beam of the plurality of beams; and 43. The method of claim 42, wherein a second parabolic mirror is configured to reflect each beam of the plurality of beams onto a respective area of ​​a plurality of areas adjacent to a pixel on the wafer. 44. The method of clause 43, wherein each beam of the plurality of beams indirectly heats a pixel. 45. The method of clause 44, wherein the multiple beams form a ring shape surrounding the pixel. 46. ​​The method of any one of clauses 27 to 45, wherein the pixel comprises a plurality of pixels. 47. The method of any one of clauses 27 to 46, wherein the defect comprises multiple defects. 48. The method of any one of clauses 29-47, wherein the laser source comprises one of an infrared laser, a visible laser, or an ultraviolet laser. 49. The laser source includes a plurality of laser sources; and 49. The method of any one of clauses 29 or 48, wherein at least one laser source of the plurality of laser sources is configured to condition a plurality of surface charges on the wafer. 50. The method of any one of clauses 27 to 49, wherein the temperature of the pixel reaches the operating temperature of the pixel by indirect heating. 51. The method of any one of clauses 27 to 50, wherein the pixel comprises a PN junction. 52. The method of any one of clauses 27 to 50, wherein the pixel comprises a bulk material. 53. A non-transitory computer-readable medium storing a set of instructions executable by at least one processor of a computing device to cause a computing device to perform an inspection method, the method comprising: emitting a beam from the module that illuminates an area adjacent to the pixel on the wafer to indirectly heat the pixel, thereby mitigating the source of direct photon-induced effects at the pixel; Detecting defects in the pixel, the defects being induced by indirect heating of the pixel; 1. A non-transitory computer-readable medium comprising: 54. A set of instructions executable by at least one processor of a computing device comprises: Detecting defects using voltage contrast 54. The non-transitory computer-readable medium of claim 53, further causing a computing device to execute: 55. The non-transitory computer-readable medium of any one of clauses 53-54, wherein the module includes a laser source. 56. The beam comprises a plurality of beams and the laser source comprises a plurality of laser sources, and a set of instructions executable by at least one processor of a computing device comprises: 56. The non-transitory computer-readable medium of clause 55, further causing the computing device to emit one beam of the plurality of beams from each laser source of the plurality of laser sources. 57. The non-transitory computer-readable medium of clause 56, wherein the area includes a plurality of areas, and each beam of the plurality of beams illuminates each area of ​​the plurality of areas adjacent to a pixel on the wafer. 58. The non-transitory computer-readable medium of clause 57, wherein each beam of the plurality of beams indirectly heats a pixel. 59. The non-transitory computer-readable medium of any one of clauses 53-54, wherein the module further includes a beam splitter and a mirror. 60. The non-transitory computer-readable medium of clause 59, wherein the beam splitter is configured to split the beam into multiple beams. 61. The non-transitory computer-readable medium of clause 60, wherein the area includes a plurality of areas, and the mirror is configured to reflect each beam of the plurality of beams to each area of ​​the plurality of areas. 62. The non-transitory computer-readable medium of clause 61, wherein each beam of the plurality of beams illuminates each area of ​​the plurality of areas adjacent to a pixel on the wafer. 63. The non-transitory computer-readable medium of clause 62, wherein each beam of the plurality of beams indirectly heats a pixel. 64. The non-transitory computer-readable medium of clause 63, wherein the beam splitter comprises a plurality of beam splitters. 65. The non-transitory computer-readable medium of any one of clauses 63-64, wherein the mirror comprises multiple mirrors. 66. The non-transitory computer-readable medium of any one of clauses 53-54, wherein the beam comprises multiple beams. 67. The non-transitory computer-readable medium of clause 66, wherein the module further includes a first parabolic mirror and a second parabolic mirror. 68. The non-transitory computer-readable medium of clause 67, wherein the first parabolic mirror is configured to reflect each beam of the plurality of beams to the second parabolic mirror. 69. An area includes multiple areas, a second parabolic mirror configured to receive each beam of the plurality of beams; and 69. The non-transitory computer-readable medium of clause 68, wherein a second parabolic mirror is configured to reflect each beam of the plurality of beams to a respective area of ​​the plurality of areas adjacent to a pixel on the wafer. 70. The non-transitory computer-readable medium of clause 69, wherein each beam of the plurality of beams indirectly heats a pixel. 71. The non-transitory computer-readable medium of clause 70, wherein the multiple beams form a ring shape surrounding the pixel. 72. The non-transitory computer-readable medium of any one of clauses 53-71, wherein the pixel comprises a plurality of pixels. 73. The non-transitory computer-readable medium of any one of clauses 53-72, wherein the defect includes multiple defects. 74. The non-transitory computer-readable medium of any one of clauses 55-73, wherein the laser source includes one of an infrared laser, a visible laser, or an ultraviolet laser. 75. The laser source includes multiple laser sources; and 75. The non-transitory computer-readable medium of any one of clauses 55 or 74, wherein at least one laser source of the plurality of laser sources is configured to adjust a plurality of surface charges on the wafer. 76. The non-transitory computer-readable medium of any one of clauses 53 to 75, wherein indirect heating causes the temperature of the pixel to reach the pixel's operating temperature. 77. The non-transitory computer-readable medium of any one of clauses 53-76, wherein the pixel includes a PN junction. 78. The non-transitory computer-readable medium of any one of clauses 53-76, wherein the pixel comprises a bulk material. 79. An electron beam system comprising: a module configured to emit a beam that illuminates a pixel on the wafer to heat the pixel, thereby mitigating the source of direct photon-induced effects at the pixel; an electron beam tool configured to detect defects in the pixel, the defects being induced by heating of the pixel; and Including, the system. 80. The system of clause 79, wherein the module includes an infrared laser. 81. The system of any one of clauses 1-26, wherein the modules include an advanced charge controller (ACC) module. 82. The system of any one of clauses 1-26 or 81, wherein the cause includes multiple causes. 83. The system of any one of clauses 1-26 or 81-82, wherein mitigating the source of direct photon-induced effects in the pixel includes generating substantially zero photon-induced charge in the pixel or causing substantially zero photon-induced carrier density change in the pixel. 84. The method of any one of clauses 27-52, wherein the module includes an advanced charge controller (ACC) module. 85. The method of any one of clauses 27-52 or 84, wherein the cause includes multiple causes. 86. The method of any one of clauses 27-52 or 84-85, wherein mitigating the source of direct photon-induced effects in the pixel includes generating substantially zero photon-induced charge in the pixel or causing substantially zero photon-induced carrier density change in the pixel. 87. The non-transitory computer-readable medium of any one of clauses 53-78, wherein the module includes an advanced charge controller (ACC) module. 88. The non-transitory computer-readable medium of any one of clauses 53-78 or 87, wherein the cause includes multiple causes. 89. The non-transitory computer-readable medium of any one of clauses 53-78 or 87-88, wherein mitigating the source of direct photon-induced effects in the pixel includes generating substantially zero photon-induced charge in the pixel or causing substantially zero photon-induced carrier density change in the pixel. 90. The system of any one of clauses 79-80, wherein the modules include an advanced charge controller (ACC) module. 91. The system of any one of clauses 79-80 or 90, wherein the cause includes multiple causes. 92. The system of any one of clauses 79-80 or 90-91, wherein mitigating the source of direct photon-induced effects in the pixel includes generating substantially zero photon-induced charge in the pixel or causing substantially zero photon-induced carrier density change in the pixel.

[0100]

[0111] It will be understood that the embodiments of the present disclosure are not limited to the exact constructions described above and illustrated in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof.

Claims

1. 1. An electron beam system comprising: a module configured to emit a beam that illuminates an area adjacent to a pixel on the wafer to indirectly heat the pixel and thereby mitigate the source of direct photon-induced effects at the pixel; an electron beam tool configured to detect defects in the pixel, the defects induced by the indirect heating of the pixel; and Including, the system.

2. The system of claim 1 , wherein the electron beam tool is further configured to detect the defects using voltage contrast.

3. The system of claim 1 , wherein the module includes a laser source.

4. the beam comprises a plurality of beams; the laser source includes a plurality of laser sources; and The system of claim 3 , wherein each laser source of the plurality of laser sources is configured to emit one beam of the plurality of beams.

5. 5. The system of claim 4, wherein the area comprises a plurality of areas, and each beam of the plurality of beams illuminates a respective area of ​​the plurality of areas adjacent the pixel on the wafer.

6. The system of claim 5 , wherein each beam of the plurality of beams indirectly heats the pixel.

7. The system of claim 1 , wherein the module further comprises a beam splitter and a mirror.

8. The system of claim 7 , wherein the beam splitter is configured to split the beam into multiple beams.

9. The system of claim 8 , wherein the area comprises a plurality of areas, and the mirror is configured to reflect each beam of the plurality of beams to a respective area of ​​the plurality of areas.

10. 10. The system of claim 9, wherein each beam of the plurality of beams illuminates a respective area of ​​the plurality of areas adjacent the pixel on the wafer.

11. The system of claim 10 , wherein each beam of the plurality of beams indirectly heats the pixel.

12. The system of claim 11 , wherein the beam splitter comprises a plurality of beam splitters.

13. The system of claim 11 , wherein the mirror comprises a plurality of mirrors.

14. The system of claim 1 , wherein the beam comprises a plurality of beams.

15. The system of claim 14 , wherein the module further comprises a first parabolic mirror and a second parabolic mirror.

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