Electron energy fluctuation stabilizing and compensating methods and techniques for electron-beam systems

Abstract

A method of particle beam parameter variation compensation for image inspection and enhancement are disclosed. Embodiments of the disclosure may provide a charged-particle beam parameter variation compensation method to correct electron source and electron beamlet fluctuations. Some embodiments of the disclosure may provide a method of monitoring an electrical signal of an electron source in real-time for fluctuations outside a threshold value and applying an adjustment signal to a component of a charged-particle beam apparatus based on the monitored electrical signal. The fluctuations of an electron beamlet may result from fluctuations of the electron source. This real-time fluctuation data may be used to adjust an image to remove unwanted noise and enable improved inspection accuracy and associated improved accuracy of metrology measurements.

Description

ELECTRON ENERGY FLUCTUATION STABILIZING AND COMPENSATING METHODS AND TECHNIQUES FOR ELECTRON-BEAM SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of WO application PCT / CN2024 / 070805 which was filed on January 5, 2024 and WO application PCT / CN2024 / 107116 which was filed on July 23, 2024 and WO application PCT / CN2024 / 107904 which was filed on July 26, 2024 and WO application PCT / CN2024 / 136794 which was filed on December 4, 2024 which are incorporated herein in its entirety by reference.FIELD

[0002] The embodiments provided herein relate to a charged-particle beam energy variation compensation technology. A charged particle beam system may be used to continuously compensate fluctuations in charged-particle beam energy levels and resolve image performance issues related to charged particle beam energy fluctuations.BACKGROUND

[0003] In manufacturing processes of integrated circuits (ICs), unfinished or finished circuit components are inspected to ensure that they are manufactured according to design and are free of defects. Inspection systems utilizing optical microscopes or charged particle (e.g., electron) beam microscopes, such as a scanning electron microscope (SEM) can be employed. As the physical sizes of IC components continue to shrink, accuracy and yield in defect detection become increasingly important. Inspection images such as SEM images can be used to identify or classify defects of the manufactured ICs. Improvements to detection performance, image quality, or throughput of the inspection systems are desired.SUMMARY

[0004] The embodiments provided herein disclose a charged-particle beam inspection apparatus, and more particularly, a method of charged-particle beam parameter variation compensation, inspection image acquisition, and inspection image enhancement.

[0005] Some embodiments provide a circuit configured to reduce a characteristic in a power supply for a charged particle system, the circuit comprising a low pass filter (LPF) communicatively coupled to an input supply and configured to filter an electrical signal provided by the input supply, wherein the input supply is a voltage source or a current source, and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the input supply.

[0006] In some embodiments, a charged particle system is provided. The charged particle system comprises a charged particle source configured to emit a primary beam of charged particles, wherein the primary beam of charged particles has a first characteristic, a power supply configured to provide an electrical signal to the charged particle source to cause the charged particle source to emit the primary beam of charged particles, wherein the power supply is a voltage source or a current source, and a circuit configured to reduce a characteristic in the electrical signal provided to the charged particle source by the power supply, wherein the circuit comprises a low pass filter (LPF) communicatively coupled to the power supply and configured to filter the electrical signal provided by the power supply, and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the power supply.

[0007] In some embodiments, a power supply for a charged particle beam system is provided. The power supply may be configured to provide an electrical signal to a charged particle source, wherein the electrical signal causes the charged particle source to emit a primary beam of charged particles, wherein the power supply is communicatively coupled to a circuit configured to reduce a characteristic in the electrical signal provided to the charged particle source by the power supply, and wherein the circuit comprises a low pass filter (LPF) communicatively coupled to the power supply and configured to filter the electrical signal provided by the power supply, and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the power supply.

[0008] Other advantages of the embodiments of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of the present disclosure.BRIEF DESCRIPTION OF FIGURES

[0009] The above and other aspects of the present disclosure will become more apparent from the description of exemplary embodiments, taken in conjunction with the accompanying drawings.

[0010] FIG. l is a schematic diagram illustrating an example charged-particle beam inspection system, consistent with embodiments of the present disclosure.

[0011] FIG. 2 is a schematic diagram illustrating an example multi-beam tool that can be a part of the example charged-particle beam inspection system of FIG. 1, consistent with embodiments of the present disclosure.

[0012] FIG. 3 is an example schematic of a power supply for a charged particle source in multi-beam tool 104, consistent with embodiments of the present disclosure.

[0013] FIG. 4 is an example schematic of a charged particle beam tool configured to emit charged particle beamlets, consistent with embodiments of the present disclosure.

[0014] FIG. 5 is an example schematic of a charged particle system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure.

[0015] FIG. 6 is an example schematic of a charged particle system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure.

[0016] FIG. 7 is an example schematic of a charged particle beam system configured to emit charged particle beamlets, consistent with embodiments of the present disclosure.

[0017] FIG. 8 is an example schematic of a charged particle beam system configured to emit charged particle beamlets, consistent with embodiments of the present disclosure.

[0018] FIG. 9 is an example schematic diagram of a charged particle beam system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure.

[0019] FIG. 10 is an example schematic diagram of a charged particle beam system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure.

[0020] FIGs. 11A, 11B, and 11C are example schematics of a charged particle beam system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure.

[0021] FIG. 12 is an example schematic diagram of a charged particle beam system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure.

[0022] FIG. 13 is a flowchart representing an example process for compensating for variations in charged particle beam energy in generation of an image, consistent with embodiments of the present disclosure.

[0023] FIG. 14 is a flowchart representing an example process for compensating for variations in charged particle beam energy in generation of an image, consistent with embodiments of the present disclosure.

[0024] FIG. 15 is an example schematic of a system to compensate energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure.

[0025] FIG. 16 is a flowchart representing an example process for compensating for variations in charged particle beam energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure.

[0026] FIG. 17 is a flowchart representing an example process for compensating for variations in charged particle beam energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure.

[0027] FIG. 18A is an example schematic of a system to stabilize energy fluctuations in a power supply for a charged particle source, consistent with embodiments of the present disclosure.

[0028] FIGS. 18B, 18C, 18D, 18E, 18F, 18G, and 18H are example schematics of an output stabilizer to regulate output fluctuations in a power supply for a charged particle source, consistent with embodiments of the present disclosure.

[0029] FIG. 19 is an example illustration of a capacitor matrix to regulate output fluctuations in a first component in a charged particle source, consistent with embodiments of the present disclosure.

[0030] FIG. 20 is a flowchart representing an example process for compensating for variations in charged particle beam energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure.

[0031] FIGS. 21A and 21B are example illustrations of an uncompensated versus compensated fluctuation of an output signal from a power supply to a charged particle source, consistent with embodiments of the present disclosure.DETAILED DESCRIPTION

[0032] 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 the same numbers in different drawings represent the same or similar elements unless otherwise represented. The implementations set forth in the following description of exemplary embodiments do not represent all implementations. Instead, they are merely examples of apparatuses and methods consistent with aspects related to the disclosed embodiments as recited in the appended claims. For example, although some embodiments are described in the context of utilizing electron beams, the disclosure is not so limited. Other types of charged-particle beams (e.g., including protons, ions, muons, or any other particle carrying electric charges) may be similarly applied. Furthermore, other imaging systems may be used, including but not limited to, optical imaging, photon detection, x- ray detection, ion detection, etc.

[0033] Electronic devices are constructed of circuits formed on a piece of semiconductor material called a substrate. The semiconductor material may include, for example, silicon, gallium arsenide, indium phosphide, or silicon germanium, or the like. Many circuits may be formed together on the same piece of silicon and are called integrated circuits or ICs. The size of these circuits has decreased dramatically so that many more of them can be fitted on the substrate. For example, an IC chip in a smartphone can be as small as a thumbnail and yet may include over 2 billion transistors, the size of each transistor being less than 1 / 1000th the size of a human hair.

[0034] Making these ICs with extremely small structures or components is a complex, timeconsuming, and expensive process, often involving hundreds of individual steps. Errors in even one step have the potential to result in defects in the finished IC, rendering it useless. Thus, one goal of the manufacturing process is to avoid such defects to maximize the number of functional ICs made in the process; that is, to improve the overall yield of the process.

[0035] One component of improving yield is monitoring the chip-making process to ensure that it is producing a sufficient number of functional integrated circuits. One way to monitor the process is to inspect the chip circuit structures at various stages of their formation. Inspection can be carried out using an inspection tool such as, for example, a scanning charged-particle microscope (SCPM). For example, an SCPM may be a scanning electron microscope (SEM). A SCPM inspection tool can be used to image these extremely small structures, in effect, taking a “picture” of the structures of the wafer to generate an inspection image. The inspection image can be used to determine if the structure was formed properly in the proper location. If the structure is defective, then the process can be adjusted, so the defect is less likely to recur.

[0036] As the physical sizes of IC components continue to shrink, accuracy and yield in defect detection become more important. Inspection images such as SCPM images can be used for metrology measurements (e.g., to identify or classify defects) of the manufactured ICs. Measurements including, but not limited to, critical dimensions of the inspection image may be used to identify defects on the wafer. In order to perform metrology measurements more accurately, it is desired to obtain inspection images that are accurately focused, have high-quality contrast, and improved signal- to-noise ratios. One way to improve the quality of inspection images may be to monitor the energy stability of a charged particle beam (e.g., electron beam) and correct any deviation of the charged particle beam energy stability from a threshold value during imaging.

[0037] For example, a SEM scans the surface of a sample with a focused beam of primary electrons. The primary electrons interact with the sample and generate secondary electrons. By scanning the sample with the focused beam and capturing the secondary electrons with a detector, the SEM creates an image of the scanned area of the sample. For high throughput inspection, some of the inspection systems use multiple focused beams of primary electrons. As the multiple focused beams can scan different parts of a sample at the same time, multi-beam inspection system can inspect a sample at a much higher speed than a single-beam inspection system.

[0038] In a SEM, primary electrons are generated by an electron gun (also called an electron source). In the source, the primary electrons are created using electron emission from the cathode tip; then, they are accelerated to the energies necessary for transporting them through the electron-optical system of SEM to the sample. The electron source may be of thermal emission, field emission, or Schottky (field enhanced thermionic) emission types, among others. To obtain high-quality images of the sample, keeping the electron energy of primary electron beam consistent and stable is critical. Electron sources, however, may show short- and long-term fluctuations and drift of the emission current. The primary beam from the electron source may exhibit changes in the angular distribution of the emitted current density and the virtual source position. These fluctuations may affect the stability of the primary electron beamlets hitting the surface of the sample and lead to variation of the secondary electron signal collected from the imaged surface, which ultimately affects the image quality and reproducibility of the images.

[0039] Embodiments of the disclosure may provide a charged-particle beam parameter variation compensation method to correct electron source and electron beamlet fluctuations. Some embodiments of the disclosure may provide a method of monitoring an electrical signal of an electron source in real-time for fluctuations outside a threshold value and applying an adjustment signal to a component of a charged-particle beam apparatus based on the monitored electrical signal outside the threshold value. In some embodiments, the component of the charged-particle beam apparatus may change a parameter of the charged-particle beam. The component of the charged-particle beam apparatus may be a condenser lens, an objective lens, a sample stage, a scanning deflection unit, a charged particle source, or an auxiliary lens, and the parameter of the charged-particle beam may be a trajectory of the charged-particle beam. The fluctuations of an electron beamlet may result from, for example, fluctuations of the electron source. This real time fluctuation data may be used to adjust an image to improve the image quality, such as by removing unwanted noise in the image resulting from the forementioned fluctuations, enabling improved accuracy of inspection images and associated improved accuracy metrology based on these images. Some embodiments of the disclosure provide a charged-particle beam system configured to improve regulation of an electron source and emitted electron beamlet fluctuations. In some embodiments, the charged-particle beam system comprises a circuit configured to improve a dynamic load regulation of a high voltage power supply for the electron source. In some embodiments, the circuit is powered by a low voltage power supply floating on the high voltage supply for the electron source. Accordingly, the circuit avoids large voltage variations between components and is able to filter and amplify a high voltage signal (e.g., 30 kV). The circuit may then provide a high voltage signal with reduced fluctuation to the electron source and enable the electron source to emit an electron beamlet with reduced fluctuation. Thus, embodiments of the disclosure may improve the quality of a generated image of a sample, minimize sources of error during sample inspection, and improve metrology measurement accuracy.

[0040] Relative dimensions of components in drawings may be exaggerated for clarity. Within the following description of drawings, the same or like reference numbers refer to the same or like components or entities, and only the differences with respect to the individual embodiments are described. As used herein, unless specifically stated otherwise, the term “or” encompasses all possible combinations, except where infeasible. For example, if it is stated that a component may include A or B, then, unless specifically stated otherwise or infeasible, the component may include A, or B, or A and B. As a second example, if it is stated that a component may include A, B, or C, then, unless specifically stated otherwise or infeasible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0041] FIG. l illustrates an example electron beam inspection (EBI) system 100 consistent with embodiments of the present disclosure. EBI system 100 may be used for imaging. As shown in FIG.1, EBI system 100 includes a main chamber 101, a load / lock chamber 102, a beam tool 104, and an equipment front end module (EFEM) 106. Beam tool 104 is located within main chamber 101. EFEM106 includes a first loading port 106a and a second loading port 106b. EFEM 106 may include additional loading port(s). First loading port 106a and second loading port 106b receive sample front opening unified pods (FOUPs) that contain samples (e.g., semiconductor wafers or wafers made of other material(s)). A “lot” is a plurality of samples that may be loaded for processing as a batch.

[0042] One or more robotic arms (not shown) in EFEM 106 may transport the samples to load / lock chamber 102. Load / lock chamber 102 is connected to a load / lock vacuum pump system (not shown) which removes gas molecules in load / lock chamber 102 to reach a first pressure below the atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) may transport the sample from load / lock chamber 102 to main chamber 101. Main chamber 101 is connected to a main chamber vacuum pump system (not shown) which removes gas molecules in main chamber 101 to reach a second pressure below the first pressure. After reaching the second pressure, the sample is subject to inspection by beam tool 104. Beam tool 104 may be a single-beam system or a multi-beam system.

[0043] A controller 109 is electronically connected to beam tool 104. Controller 109 may be a computer configured to execute various controls of EBI system 100. Controller 109 may also include processing circuitry configured to execute various signal and image processing functions. While controller 109 is shown in FIG. 1 as being outside of the structure that includes main chamber 101, load / lock chamber 102, and EFEM 106, it is appreciated that controller 109 may be a part of the structure.

[0044] In some embodiments, controller 109 may include one or more processors (not shown). A processor may be a generic or specific electronic device capable of manipulating or processing information. For example, the processor may include any combination of any number of a central processing unit (or “CPU”), a graphics processing unit (or “GPU”), an optical processor, a programmable logic controllers, a microcontroller, a microprocessor, a digital signal processor, a hardware accelerator, an intellectual property (IP) core, a Programmable Logic Array (PLA), a Programmable Array Logic (PAL), a Generic Array Logic (GAL), a Complex Programmable Logic Device (CPLD), a Field-Programmable Gate Array (FPGA), a System On Chip (SoC), an Application-Specific Integrated Circuit (ASIC), a neural processing unit (NPU), and any other type of circuit capable of data processing. The processor may also be a virtual processor that includes one or more processors distributed across multiple machines or devices coupled via a network.

[0045] In some embodiments, controller 109 may further include one or more memories (not shown). A memory may be a generic or specific electronic device capable of storing codes and data accessible by the processor (e.g., via a bus). For example, the memory may include any combination of any number of a random-access memory (RAM), a read-only memory (ROM), an optical disc, a magnetic disk, a hard drive, a solid-state drive, a flash drive, a security digital (SD) card, a memory stick, a compact flash (CF) card, or any type of storage device. The codes and data may include an operating system (OS) and one or more application programs (or “apps”) for specific tasks. The memory mayalso be a virtual memory that includes one or more memories distributed across multiple machines or devices coupled via a network.

[0046] FIG. 2 illustrates a schematic diagram of an example multi-beam tool 104 (also referred to herein as apparatus 104) and an image processing system 290 that may be configured for use in EBI system 100 (FIG. 1), consistent with embodiments of the present disclosure. Beam tool 104 comprises a charged-particle source 202, a gun aperture 204, a condenser lens 206, a primary charged-particle beam 210 emitted from charged-particle source 202, a source conversion unit 212, a plurality of beamlets 214, 216, and 218 of primary charged-particle beam 210, a primary projection optical system 220, a motorized stage 280, a sample holder 282, multiple secondary charged-particle beams 236, 238, and 240, a secondary optical system 242, and a charged-particle detection device 244. Primary projection optical system 220 may comprise a beam separator 222, a deflection scanning unit 226, and an objective lens 228. Charged-particle detection device 244 may comprise detection sub-regions 246, 248, and 250.

[0047] Charged-particle source 202, gun aperture 204, condenser lens 206, source conversion unit 212, beam separator 222, deflection scanning unit 226, and objective lens 228 may be aligned with a primary optical axis 260 of apparatus 104. Secondary optical system 242 and charged-particle detection device 244 may be aligned with a secondary optical axis 252 of apparatus 104.

[0048] Charged-particle source 202 may emit one or more charged particles, such as electrons, protons, ions, muons, or any other particle carrying electric charges. In some embodiments, charged- particle source 202 may be an electron source. For example, charged-particle source 202 may include a cathode, an extractor, or an anode, wherein primary electrons may be emitted from the cathode and extracted or accelerated to form primary charged-particle beam 210 (in this case, a primary electron beam) with a crossover (virtual or real) 208. For ease of explanation without causing ambiguity, electrons are used as examples in descriptions herein. However, it should be noted that any charged particle may be used in any embodiment of this disclosure, which is not limited to electrons. Primary electron beam 210 may be visualized as being emitted from crossover 208. Gun aperture 204 may block off peripheral electrons of primary electron beam 210 to reduce Coulomb effect. The Coulomb effect may cause an increase in size of probe spots.

[0049] Source conversion unit 212 may comprise an array of image-forming elements and an array of beam-limit apertures. The array of image-forming elements may comprise an array of microdeflectors or micro-lenses. The array of image-forming elements may form a plurality of parallel images (virtual or real) of crossover 208 with a plurality of beamlets 214, 216, and 218 of primary electron beam 210. The array of beam-limit apertures may limit the plurality of beamlets 214, 216, and 218. While three beamlets 214, 216, and 218 are shown in FIG. 2, embodiments of the present disclosure are not so limited. For example, in some embodiments, beam tool 104 may be configured to generate a first number of beamlets. In some embodiments, the first number of beamlets may be in a range from 1 to 10000. Controller 109 may be connected to various parts of electron beaminspection system 100 of FIG. 1, such as, but not limited to, source conversion unit 212, electron detection device 244, primary projection optical system 220, or motorized stage 280. In some embodiments, controller 109 may perform various image and signal processing functions. Controller 109 may also generate various control signals to govern operations of the electron beam inspection system.

[0050] Condenser lens 206 may collimate primary electron beam 210. The electric currents of beamlets 214, 216, and 218 down-beam of source conversion unit 212 may be varied by adjusting the focusing power of condenser lens 206 or by changing the radial sizes of the corresponding beam-limit apertures within the array of beam-limit apertures. Objective lens 228 may focus beamlets 214, 216, and 218 onto a sample 230 for imaging, and may form a plurality of probe spots 270, 272, and 274 on a surface of sample 230.

[0051] Beam separator 222 may be a beam separator of Wien filter type generating an electrostatic dipole field and a magnetic dipole field. In some embodiments, if they are applied, the force exerted by the electrostatic dipole field on an electron of beamlets 214, 216, and 218 may be substantially equal in magnitude and opposite in a direction to the force exerted on the electron by magnetic dipole field. Beamlets 214, 216, and 218 may, therefore, pass straight through beam separator 222 with zero deflection angle. However, the total dispersion of beamlets 214, 216, and 218 generated by beam separator 222 may also be non-zero. Beam separator 222 may separate secondary electron beams 236, 238, and 240 from beamlets 214, 216, and 218 and direct secondary electron beams 236, 238, and 240 towards secondary optical system 242.

[0052] Deflection scanning unit 226 may deflect beamlets 214, 216, and 218 to scan probe spots 270, 272, and 274 over a surface area of sample 230. In response to the incidence of beamlets 214, 216, and 218 at probe spots 270, 272, and 274, secondary electron beams 236, 238, and 240 may be emitted from sample 230. Secondary electron beams 236, 238, and 240 may comprise electrons with a distribution of energies. For example, secondary electron beams 236, 238, and 240 may include secondary electrons (energies < 50 eV) and backscattered electrons (energies between 50 eV and landing energies of beamlets 214, 216, and 218). Secondary optical system 242 may focus secondary electron beams 236, 238, and 240 onto detection sub-regions 246, 248, and 250 of electron detection device 244. Detection sub-regions 246, 248, and 250 may be configured to detect corresponding secondary electron beams 236, 238, and 240 and generate corresponding signals (e.g., voltage or current) used to reconstruct an image of structures on or underneath the surface area of sample 230. The generated corresponding signals may also include a spectrum of frequencies, wherein a low- frequency regime contains information about larger features of sample 230 and a high-frequency regime contains information about finer (i.e., sharper) features of sample 230.

[0053] The generated signals may represent intensities of secondary electron beams 236, 238, and 240 and may be provided to image processing system 290 that is in communication with electron detection device 244, primary projection optical system 220, and motorized sample stage 280. Themovement speed of motorized sample stage 280 may be synchronized and coordinated with the beam deflections controlled by deflection scanning unit 226, such that the movement of the scan probe spots (e.g., scan probe spots 270, 272, and 274) may orderly cover regions of interests on the sample 230. The parameters of such synchronization and coordination may be adjusted to adapt to different materials of sample 230. For example, different materials of sample 230 may have different resistance-capacitance characteristics that may cause different signal sensitivities to the movement of the scan probe spots.

[0054] The intensity of secondary electron beams 236, 238, and 240 may vary according to the external or internal structure of sample 230, and thus may indicate whether sample 230 includes defects. Moreover, as discussed above, beamlets 214, 216, and 218 may be projected onto different locations of the top surface of sample 230, or different sides of local structures of sample 230, to generate secondary electron beams 236, 238, and 240 that may have different intensities. Therefore, by mapping the intensity of secondary electron beams 236, 238, and 240 with the areas of sample 230, image processing system 290 may reconstruct an image that reflects the characteristics of internal or external structures of sample 230.

[0055] In some embodiments, image processing system 290 may include an image acquirer 292, a storage 294, and a controller 296. Image acquirer 292 may comprise one or more processors. For example, image acquirer 292 may comprise a computer, server, mainframe host, terminals, personal computer, any other appropriate mobile computing devices. Image acquirer 292 may be communicatively coupled to electron detection device 244 of apparatus 104 through a medium such as an electric conductor, optical fiber cable, portable storage media, IR, Bluetooth, internet, wireless network, or wireless radio. In some embodiments, image acquirer 292 may receive a signal from electron detection device 244 and may construct an image. Image acquirer 292 may thus acquire SEM images of sample 230. Image acquirer 292 may also perform various post-processing functions, including, but not limited to, generating contours and superimposing indicators on an acquired image. Image acquirer 292 may be configured to perform adjustments of brightness and contrast of acquired images. In some embodiments, storage 294 may be a storage medium including, but not limited to, a hard disk, flash drive, cloud storage, random access memory (RAM), or other types of computer- readable memory. Storage 294 may be coupled with image acquirer 292 and may be used for saving scanned raw image data as original images and post-processed images. Image acquirer 292 and storage 294 may be connected to controller 296. In some embodiments, image acquirer 292, storage 294, and controller 296 may be integrated together as one control unit.

[0056] In some embodiments, image acquirer 292 may acquire one or more SEM images of a sample based on an imaging signal received from electron detection device 244. An imaging signal may correspond to a scanning operation for conducting charged particle imaging. An acquired image may be a single image comprising a plurality of imaging areas. The single image may be stored in storage 294. The single image may be an original image that may be divided into a plurality of regions. Eachof the regions may comprise one imaging area containing a feature of sample 230. The acquired images may comprise multiple images of a single imaging area of sample 230 sampled multiple times over a time sequence. The multiple images may be stored in storage 294. In some embodiments, image processing system 290 may include circuitry configured to perform image processing steps with the multiple images of the same location of sample 230.

[0057] In some embodiments, image processing system 290 may include measurement circuitry (e.g., analog-to-digital converters) configured to obtain a distribution of the detected secondary electrons. The electron distribution data collected during a detection time window, in combination with corresponding scan path data of beamlets 214, 216, and 218 incident on the sample surface, may be used to reconstruct images of the sample structures under inspection. The reconstructed images may be used to reveal various features of the internal or external structures of sample 230, and thereby may be used to reveal any defects that may exist in the sample.

[0058] When electrons of primary electron beam 210 are projected onto a surface of sample 230 (e.g., probe spots 270, 272, and 274), the electrons of primary electron beam 210 may penetrate the surface of sample 230 for a certain depth, interacting with particles of sample 230. Some electrons of primary electron beam 210 may elastically interact with (e.g., in the form of elastic scattering or collision) the materials of sample 230 and may be reflected or recoiled out of the surface of sample 230. An elastic interaction conserves the total kinetic energies of the bodies (e.g., electrons of primary electron beam 210) of the interaction, in which the kinetic energy of the interacting bodies does not convert to other forms of energy (e.g., heat or electromagnetic energy). Such reflected electrons generated from elastic interaction may be referred to as backscattered electrons (BSEs). Some electrons of primary electron beam 210 may inelastically interact with (e.g., in the form of inelastic scattering or collision) the materials of sample 230. An inelastic interaction does not conserve the total kinetic energies of the bodies of the interaction, in which some or all of the kinetic energy of the interacting bodies converts to other forms of energy. For example, through the inelastic interaction, the kinetic energy of some electrons of primary electron beam 210 may cause electron excitation and transition of atoms of the materials. Such inelastic interaction may also generate electrons exiting the surface of sample 230, which may be referred to as secondary electrons (SEs). Yield or emission rates of BSEs and SEs may depend on the material under inspection and the landing energy of the electrons of primary electron beam 210 landing on the surface of the material, among other factors. The energy of the electrons of primary electron beam 210 may be imparted in part by its acceleration voltage (e.g., the acceleration voltage between the anode and cathode of electron source 202 in FIG. 2). The quantity of BSEs and SEs may be more or fewer (or even the same) than the injected electrons of primary electron beam 210.

[0059] While FIG. 2 shows detection device 244 having several detection sub-regions aligned with secondary optical axis 252, it is appreciated that other multi-beam detector schemes may exist. For example, it is appreciated that a detector may correspond with each beamlet, such as a differentdetector for each of beamlets 214, 216, 218. It is appreciated that these different detectors may be positioned under the primary column corresponding to primary axis 260. For example, these different detectors could be positioned between primary projection optical system 220 and the sample stage.

[0060] Reference is now made to FIG. 3, which is an example schematic of a power supply for a charged particle source in multi-beam tool 104, consistent with embodiments of the present disclosure. FIG. 3 illustrates power supply 301 may be communicatively connected to charged particle source 302 (e.g., charged particle source 202 in FIG. 2) to supply the energy needed to cause charged particle source 302 to emit a primary charged particle beam 303 (e.g., electron beam). For example, power supply 301 may supply an electrical signal (e.g., 30 kV target) to charged particle source 302 to facilitate charged particle source 302 to emit primary beam 303 of charged particles at a desired emission current. Power supply 301 continuously provides an electrical signal to charged particle source 302. However, noise in power supply 301 (e.g., fluctuations in the provided electrical signal) or charged particle source 302 noise (e.g., fluctuations in emitted charged particle current density due to gas absorption or tip shape change) may result in fluctuations in the energy of emitted charged particle beam 303. A fluctuation in an emitted charged particle beam may be illustrated as fluctuated primary beam 304, which illustrates a broader trajectory of charged particles emitted from charged particle source 302. In some embodiments, a fluctuation to an emitted charged particle beam may narrow a trajectory of emitted charged particles (not shown). A power supply 301 fluctuation as low as 1 eV for a target signal of 30 kV may alter the trajectory of the emitted charged particle beam and prevent the charged particles from landing at a target location on a sample to be inspected. Therefore, the quality of a resulting image may be reduced, and image inspection throughput decreased.

[0061] Reference is now made to FIG. 4, which is an example schematic of a charged particle beam tool 400 configured to emit charged particle beamlets, consistent with embodiments of the present disclosure. FIG. 4 illustrates a power supply 401 communicatively connected to charged particle source 402 to form a primary charged particle beam 404. It is appreciated that primary charged particle beam 404 is comprised of a plurality of electrons generated by charged particle source 402. A source conversion unit may comprise a charged particle optical device 460, which may be a layered structure of optical elements that may include a micro-aperture array 461, a stigmator array 462, and a micro-deflector array 463. Charged particle optical device 460 may be a MEMS (microelectromechanical systems) structure. Micro-aperture array 461 may further be comprised of a plurality of first beamlet apertures 450 to cut off some charged particles in the primary charged particle beam emitted from charged particle source 402 and form charged particle beamlets 410 and 420. Charged particles in the primary charged particle beam emitted from charged particle source 402 pass through first beamlet apertures 450 to form charged particle beamlets 410 and 420, which then pass through charged particle optical device 460 towards an objective lens 406, and are focused to a focal point substantially at the surface of a sample 408. Charged particle beamlets 410 and 420 thusirradiate the surface of sample 408 and generate corresponding secondary charged particle beamlets that are then captured by a charged particle detection device to generate one or more images of the sample. It is appreciated that the number of beamlet apertures 450 is not so limited as illustrated in FIG. 4, and that aperture substrate 461 may contain any number of beamlet apertures 450. The dotted lines 410_a and 420_a serve as an illustrative guide for the pathway charged particles in primary charged particle beam 404 that form charged particle beamlets 410 and 420 may follow when emitted from charged particle source 402. In some embodiments, all charged particle beamlets (such as charged particle beamlets 410 and 420) may be focused by a single objective lens (such as objective lens 406). In some embodiments, each charged particle beamlet may be focused by an individual objective lens.

[0062] When a fluctuation occurs to power supply 401 or charged particle source 402 as described above, a trajectory of emitted charged particle beam 404 may change. This may cause a fluctuation to trajectories of charged particle beamlets 410 and 420. This may be illustrated in FIG. 4 as dashed lines 430 and 440. Charged particles in fluctuated charged particle beamlets 430 and 440 may thus impact sample 408 at locations other than the target location or shift focus, and possibly cause an image disturbance. A fluctuation to power supply 401 or charged particle source 402 may occur rapidly and discretely during continuous operation of charged particle tool 400. Thus, such fluctuations may cause continuous and random disturbances to a collected image of sample 408.

[0063] Reference is now made to FIG. 5, which is an example schematic of a charged particle system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure. FIG. 5 illustrates that a charged particle source 502 and a power supply 501 may be communicatively coupled. In some embodiments, charged particle source 502 and power supply 501 may be communicatively coupled to electron detection device 244 of apparatus 104 through a medium such as an electric conductor, optical fiber cable, portable storage media, IR, Bluetooth, internet, wireless network, or wireless radio. Power supply 501 may supply a signal to charged particle source 502 to cause charged particle source 502 to emit a primary beam of charged particles. In some embodiments, charged particle source 502 and power supply 501 may be communicatively coupled to a controller 503 (e.g., controller 109 in FIG. 1 and FIG. 2). Controller 503 may monitor a characteristic of the emitted primary charged particle beam, a characteristic of charged particle source 502, or a characteristic of power supply 501. In some embodiments, the characteristic of the emitted primary charged particle beam is a characteristic that reflects an energy level of the emitted primary charged particle beam. In some embodiments, the characteristic of the emitted primary charged particle beam is an electrical signal. In some embodiments, the characteristic of the emitted primary charged particle beam is a fluctuation of an emission current or a fluctuation of a voltage. In some embodiments, the characteristics of power supply 501 may include a fluctuation of an electrical signal supplied to charged particle source 502. In some embodiments, the electrical signal may be a voltage or a current. In some embodiments, controller 503 may determine if themonitored characteristic deviates from a threshold value. For example, controller 503 may determine that the monitored characteristic of power supply 501 (e.g., a fluctuation of a voltage signal supplied to charged particle source 502) has a deviation outside a threshold value. In some embodiments, controller 503 may adjust the deviated characteristic and apply the adjusted characteristic to a component 504 of the charged particle system to compensate for the deviated characteristic. In some embodiments, controller 503 may calculate a difference between the monitored characteristic and a threshold value. For example, controller 503 may calculate a difference between a monitored characteristic of power supply 501 (e.g., a fluctuation of a voltage signal) supplied to charged particle source 502 and a threshold value of the characteristic of power supply 501 (e.g., an allowed fluctuation of a voltage signal). Controller 503 may calculate a second characteristic to compensate for the difference between the monitored characteristic of power supply 501 and the threshold value and apply the second characteristic to component 504. Component 504 may be a component that affects a charged particle beam energy level or energy characteristic. In some embodiments, the component may be a condenser lens, a stigmator, an objective lens, an auxiliary lens, a sample stage, a deflection scanning unit, a micro-deflector array, a component of charged particle source 502, a component of power supply 501, or any other component in a charged particle system that may alter a charged particle beam energy.

[0064] Reference is now made to FIG. 6, which is an example schematic of a charged particle system to compensate energy fluctuations in a charged particle beam, consistent with embodiments of the present disclosure. FIG. 6 illustrates a power supply 601 that may be communicatively coupled to a charged particle source 602. Power supply 601 may be communicatively coupled to a charged particle source cathode 602_l, a suppressor 602_2, an extractor 602_3, and a charged particle source anode 602_4. Power supply 601 may provide an electrical signal to charged particle source 602 via any one of the illustrated connections to cause charged particle source 602 to emit primary beam 606 of charged particles. In some embodiments, power supply 601 may be communicatively coupled to controller 603, which may continuously monitor a signal supplied from power supply 601 to charged particle source 602. As a non-limiting example, controller 603 may monitor an electrical signal (e.g., a voltage) supplied from power supply 601 to charged particle source cathode 602_l. If the supplied electrical signal deviates from a threshold value, then a deviation in primary beam 606 energy may occur. In some embodiments, the deviation in primary beam 606 energy may induce a deviation in a trajectory of primary beam 606 in a charged particle beam system. This may result in primary beam 606 impacting a sample at a location that is different from a target location. A generated image may then have reduced resolution or quality, and inspection of the sample may be negatively impacted. In some embodiments, controller 603 may determine a corrected electrical signal to compensate for the deviation in primary beam 606 energy. In some embodiments, controller 603 may calculate a position on a sample where a deviated charged particle beam may impact. In some embodiments, controller 603 may calculate a change in focus of a deviated charged particle beam. In some embodiments,controller 603 may convert the deviated signal from power supply 601 via an adjustment module 604. Controller 603 may then supply the converted signal to a trajectory component 605, which may compensate the deviated trajectory of primary beam 606. In some embodiments, adjustment module 604 may generate a converted signal based on a simulation estimation ratio. The simulation estimation ratio may generate a signal to adjust a charged particle beam trajectory from a signal from power supply 601 (e.g., a voltage). In some embodiments, the converted signal may be an electrical signal (e.g., a voltage or current) for trajectory component 605. In some embodiments, controller 603 may calculate difference between the monitored electrical signal and a threshold value. Controller 603 may calculate a second signal to compensate for the difference between the monitored signal from power supply 601 and the threshold value via adjustment module 604 and apply the second signal to trajectory component 605. In some embodiments, trajectory component 605 may be a condenser lens, a stigmator, a micro-deflector array, a deflection scanning unit, an objective lens, or an auxiliary lens.

[0065] Reference is now made back to FIG. 4, which illustrates charged particle source 402 emitting primary charged particle beam 404 after receiving a fluctuated electrical signal from power supply 401. Power supply 401 may provide an electrical signal that deviates from a threshold value and causes a fluctuation in an energy level of primary beam 404. Condenser lens 405 may under-focus primary beam 404, and fluctuated beamlets 430 and 440 are illustrated by the dotted lines. Fluctuated beamlets 430 and 440 pass through charged particle optical device 460 and are focused onto a surface of sample 408 as described above in FIG. 4. However, the energy level fluctuation of primary charged particle beam 404 results in a portion of fluctuated beamlets 430 and 440 impacting sample 408 at undesired locations. This may result in an unfocused image and other degradations to a resulting inspection image of sample 408. Modulating a condenser lens signal to condenser lens 405 (e.g., as described above in FIG. 6) may correct the trajectory for fluctuated beamlets 430 and 440 and thus compensate for the signal fluctuation from power supply 401. In some embodiments, modulating the condense lens signal may be adding an adjustment signal to an original condenser lens signal. In some embodiments, an adjustment signal applied to condenser lens 405 may be provided to a separate coil within condenser lens 405. In some embodiments, an adjustment signal may be provided to a coil within condenser lens 405 used to generate a magnetic field for a focusing effect to primary beam 404. It is appreciated that although the above description is directed to applying an adjustment signal to a condenser lens (e.g., condenser lens 405), embodiments of the present disclosure are not so limited. For example, an adjustment signal may be applied to micro deflector array 463, objective lens 406, or to a stigmator (not shown).

[0066] Reference is now made to FIG. 7, which is an example schematic of a charged particle beam tool 700 configured to emit charged particle beamlets, consistent with embodiments of the present disclosure. FIG. 7 illustrates a power supply 701 communicatively connected to charged particle source 702 to form a primary charged particle beam 704. It is appreciated that primary charged particle beam 704 is comprised of a plurality of electrons generated by charged particle source 702. Asource conversion unit may comprise a charged particle optical device 760, which may be a layered structure of optical elements that may include a micro-aperture array 761, a stigmator array 762, and a micro-deflector array 763. Charged particle optical device 760 may be a MEMS structure. Microaperture array 761 may further be comprised of a plurality of first beamlet apertures 750 to cut off some charged particles in the primary charged particle beam emitted from charged particle source 702 and form charged particle beamlets 710 and 720. Charged particles in the primary charged particle beam emitted from charged particle source 702 pass through first beamlet apertures 750 to form charged particle beamlets 710 and 720, which then pass through charged particle optical device 760 and towards primary projection optical system 770, which includes deflection scanning unit 771 and objective lens 772. Deflection scanning unit 771 deflects charged particle beamlets 710 and 720 to a target position on sample 708 and objective lens 772 focuses charged particles beamlets 710 and 720 substantially at the surface of sample 708. Charged particle beamlets 710 and 720 thus irradiate the surface of sample 708 and generate corresponding secondary charged particle beamlets that are then captured by a charged particle detection device to generate one or more images of the sample. It is appreciated that the number of beamlet apertures 750 is not so limited as illustrated in FIG. 7, and that aperture substrate 761 may contain any number of beamlet apertures 750. The dotted lines 710_a and 720_a serve as an illustrative guide for the pathway of charged particles in primary charged particle beam 704 that form charged particle beamlets 710 and 720 may follow when emitted from charged particle source 702. In some embodiments, all charged particle beamlets (such as charged particle beamlets 710 and 720) may be deflected by a single deflection scanning unit (such as deflection scanning unit 771) or focused by a single objective lens (such as objective lens 772). In some embodiments, one or more charged particle beamlets may be independently deflected by a deflecting scanning unit and independently focused by an individual objective lens.

[0067] When a fluctuation occurs in power supply 701 or charged particle source 702 as described above, a trajectory of emitted charged particle beam 704 may change. This may cause a fluctuation to trajectories of charged particle beamlets 710 and 720. A deviated charged particle beam may be illustrated in FIG. 7 as dashed lines 730 and 740 and charged particles in deviated charged particle beams 730 and 740 may have different energies compared to charged particles in charged particle beamlets 710 and 720. Deflection scanning unit 771 may over deflect or under deflect a deviated charged particle beam based on the charged particle beam energy. Charged particles in fluctuated charged particle beamlets 730 and 740 may thus impact sample 708 at locations other than the target location. Arrow 780 and arrow 781 indicate a deviation range of a charged particle impacting sample 708. Additionally, deviated charged particle beamlets 730 and 740 may have a different focus value when impacting sample 708. A shifted beam position or focus may cause a disturbance in a collected image. A fluctuation to power supply 701 or charged particle source 702 may occur rapidly and discretely during continuous operation of charged particle beam tool 700. Thus, such fluctuations may cause continuous and random disturbances to a collected image of sample 708.

[0068] Reference is now made to FIG. 8, which is an example schematic of a charged particle beam tool 800 configured to emit charged particle beamlets, consistent with embodiments of the present disclosure. FIG. 8 illustrates a power supply 801 communicatively connected to charged particle source 802 to form a primary charged particle beam 804. A variation of a signal supplied from power supply 801 to charged particle source 802 may induce an energy variation in primary charged particle beam 804, which may shift a trajectory of primary charged particle beam 804 as described above. In some embodiments, charged particle beam tool 800 may be configured to correct a trajectory of a charged particle beam. FIG. 8 illustrates a controller 809 (e.g., controller 109) may be communicatively connected to power supply 801, to condenser lens 805, micro-deflector array 863, and to a primary projection optical system 870, which may include a deflection scanning unit 871 and an objective lens 872. In some embodiments, controller 809 may monitor a first characteristic of power supply 801 and determine if first characteristic has deviated from a threshold value. In response to the determination that the first characteristic has deviated from a threshold value, controller 809 may calculate a second characteristic to compensate for the first characteristic and supply the second characteristic to primary projection optical system 870. In some embodiments, controller 809 may apply the second characteristic to condenser lens 805 to correct a trajectory of the charged particle beam. Applying the second characteristic (e.g., an adjustment signal) to condenser lens 805 may correct a trajectory for a trajectory of the charged particle beam and thus may compensate for the signal fluctuation from power supply 801. In some embodiments, controller 809 may apply the second characteristic to an original condenser lens signal. In some embodiments, the second characteristic supplied to condenser lens 805 may be provided to a separate coil within condenser lens 805. In some embodiments, the second characteristic may be provided to a coil within condenser lens 805 used to generate a magnetic field for a focusing effect to primary beam 804. In some embodiments, controller 809 may apply the second characteristic to micro-deflector array 863 to correct a trajectory of the charged particle beam. In some embodiments, micro-deflector array 863 may comprise a plurahty of electrostatic micro-deflectors. An electrostatic component may provide a faster response than a magnetic component, so applying a second characteristic to an electrostatic component may provide a faster trajectory correction than a magnetic component. In some embodiments, controller 809 may apply the second characteristic to deflection scanning unit 871 to correct a trajectory of the charged particle beam. In some embodiments, controller 809 may apply the second characteristic to objective lens 872 to correct a focus of the charged particle beam. In some embodiments, controller 809 may apply the second characteristic to an auxiliary trajectory component. In some embodiments, the auxiliary trajectory component comprises micro-deflector array 863. In some embodiments, the auxiliary trajectory component comprises an auxiliary lens. In some embodiments, controller 809 may be communicatively connected to a sample stage 880, which is connected to sample 808. Controller 809 may provide the second characteristic to sample stage 880. In some embodiments, sample stage 880 is an electrostatic chuck. In some embodiments, controller 809 may provide an electrical signal tosample stage 880. In some embodiments, an electrical characteristic (e.g., voltage) of sample stage 880 may be adjusted to adjust a characteristic (e.g., landing energy) to correct a trajectory of the charged particle beam or a focus of the charged particle beam. In some embodiments, controller 809 may provide an electrical signal to sample stage 880 to adjust a height of sample stage 880 and correspondingly correct a trajectory of the charged particle beam or a focus of the charged particle beam.

[0069] In some embodiments, the threshold value may be a negligible value (e.g., zero or essentially zero) such that controller 809 may continuously calculate a second characteristic to compensate for the first characteristic and cancel out a fluctuation of the charged particle beam trajectory (e.g., a negative feedback system). In some embodiments, the threshold value may be at least 0.003% of a signal target value.

[0070] Reference is now made to FIG. 9, which is an example schematic diagram illustrating a portion of an example charged particle beam apparatus 900, consistent with embodiments of the present disclosure. A charged particle beam 901 may be emitted from a charged particle source (not shown) and deflected by a deflection scanning unit 902 to a sample 908. Deflection scanning unit 902 may comprise coils and may receive signal to generate a magnetic field 902a to deflect charged particle beam 901. Charged particle beam 901 may be focused by objective lens 903 to a surface of sample 908. Objective lens 903 may comprise an objective lens coil 903a, which may receive a signal to generate a magnetic field 903b to focus charged particle beam 901. The signal provided to objective lens 903 may be determined based on a characteristic of charged particle beam 901. The signal provided to deflection scanning unit 902 may be determined based on a characteristic of charged particle beam 901. In some embodiments, the characteristic of charged particle beam 901 comprises an energy value of charged particle beam 901. In some embodiments, the energy value of charged particle beam 901 may be determined from a signal provided to a charged particle source from a power supply (not shown). If a signal provided to a charged particle source from a power supply deviates, a characteristic (e.g., energy value) of charged particle beam 901 may deviate. If a signal provided to a charged particle source from a power supply deviates by more than a threshold value, a characteristic (e.g., energy value) of charged particle beam 901 may deviate by more than a threshold value. In some embodiments, a trajectory of charged particle beam 901 may change, and charged particle beam 901 may impact sample 908 at a location different from a target location or with an altered focus. FIG. 9 illustrates deviated charged particle beam 904, which may be emitted from a charged particle source after the charged particle receives a deviated signal from a power supply. Deflection scanning unit 902 may deflect deviated charted particle beam 904 to a lesser extent because deviated charged particle beam 904 has a deviated characteristic (e.g., energy value). A signal provided to deflection scanning unit 902 to generate magnetic field 902a may account for a characteristic of charged particle beam 901 but not account for a deviated characteristic of deviated charged particle beam 904. Accordingly, deviated charged particle beam 904 may impact sample 908at a position different from a target position. In some embodiments, deviated charged particle beam 904 may impact sample 908 at a different lateral position. In some embodiments, deviated charged particle beam 904 may be over or under focused by objective lens 903, because deviated charged particle beam 904 has a deviated characteristic (e.g., energy value). A signal provided to objective lens 903 to generate magnetic field 903b may account for a characteristic of charged particle beam 901 but not account for a deviated characteristic of deviated charged particle beam 904.

[0071] Reference is now made to FIG. 10, which is an example schematic diagram illustrating a portion of an example charged particle beam apparatus 1000 for compensating a charged particle beam trajectory, consistent with embodiments of the present disclosure. In some embodiments, charged particle beam apparatus 1000 may emit a charged particle beam 1001. A deviation in a signal applied to a charged particle source (not shown) from a power supply (not shown) may result in charged particle beam apparatus 1000 emitting a deviated charged particle beam 1004. FIG. 10 illustrates a controller 1009 (e.g., controller 109 or controller 809) communicatively connected to a deflection scanning unit 1002. Controller 1009 may include an adjustment module (e.g., adjustment module 604 of FIG. 6) to determine a corrected signal to provide to deflection scanning unit 1002 to correct a deviated signal from a power supply (not shown). In some embodiments, controller 1009 may determine a corrected electrical signal to compensate a trajectory of a deviated charged particle beam 1004 compared to a trajectory of a charged particle beam 1001. In some embodiments, controller 1009 may convert the deviated signal from a power supply via an adjustment module (e.g., adjustment module 604 in FIG. 6). Controller 1009 may then supply the converted signal to deflection scanning unit 1002, which may generate magnetic field 1002a to compensate the deviated trajectory of deviated charged particle beam 1004. In some embodiments, controller 1009 may generate a converted signal based on a simulation estimation ratio as described above in FIG. 6. In some embodiments, a threshold value for the deviated signal may be a negligible value (e.g., zero or essentially zero) such that controller 1009 may continuously calculate a corrected signal to correct the deviated signal from the power supply. In some embodiments, the threshold value may be at least 0.003% of a signal target value. A trajectory of deviated charged particle beam 1004 may be corrected and thus impact a sample 1008 at a target location. In some embodiments, a focus of deviated charged particle beam 1004 may be corrected after passing objective lens 1003. In some embodiments, deviated charged particle beam 1004 may be out of focus when impacting sample 1008.

[0072] Reference is now made to FIG. 11A, which is an example schematic diagram illustrating a portion of an example charged particle beam apparatus 1100 for compensating a charged particle beam trajectory, consistent with embodiments of the present disclosure. In some embodiments, charged particle beam apparatus 1100 may emit a charged particle beam 1101. A deviation in a signal applied to a charged particle source (not shown) from a power supply (not shown) may result in charged particle beam apparatus 1100 emitting a deviated charged particle beam 1104. FIG. 11A illustrates a controller 1109 (e.g., controller 109, controller 809, or controller 1009) communicativelyconnected to a scanning deflection unit 1102 and to objective lens coil 1103a of objective lens 1103. Controller 1109 may include an adjustment module (e.g., adjustment module 604 of FIG. 6) to determine a corrected signal to provide to deflection scanning unit 1102 or objective lens 1103 to correct a deviated signal from a power supply (not shown). In some embodiments, a threshold value for the deviated signal may be a negligible value (e.g., zero or essentially zero) such that controller 1109 may continuously calculate a corrected signal to correct the deviated signal from the power supply. In some embodiments, the threshold value may be at least 0.003% of a signal target value. In some embodiments, controller 1109 may determine a corrected electrical signal to compensate a trajectory of a deviated charged particle beam 1104 compared to a charged particle beam 1101. Controller 1109 may then supply the converted signal to deflection scanning unit 1102, which may generate magnetic field 1102a, or objective lens coil 1103a, which may generate magnetic field 1103b, to compensate the deviated trajectory of deviated charged particle beam 1104. In some embodiments, controller 1109 may generate a converted signal based on a simulation estimation ratio as described above in FIG. 6. Deviated charged particle beam 1104 may be compensated to impact a sample 1108 at a target location at a target focus. In some embodiments, an image collected of sample 1108 may have reduced distortion.

[0073] Reference is now made to FIG. 11B, which is an example schematic diagram illustrating a portion of an example charged particle beam apparatus 1110 for compensating a charged particle beam trajectory, consistent with embodiments of the present disclosure. FIG. 11B illustrates controller 1109 is communicatively connected to scanning deflection unit 1102 and to a second coil 1103c of objective lens 1103. In some embodiments, second coil 1103c may be smaller than objective lens coil 1103a. In some embodiments, second coil 1103c may be positioned lower than objective lens coil 1103a. In some embodiments, second coil 1103c may be positioned above objective lens coil 1103a. In some embodiments, second coil 1103c may be interspersed in objective lens coil 1103a. In some embodiments, a position of second coil 1103c may be determined by simulation. In some embodiments, controller 1109 may determine a corrected electrical signal to compensate a trajectory of deviated charged particle beam 1104 compared to charged particle beam 1101. Controller 1109 may then supply the converted signal to deflection scanning unit 1102, which may generate magnetic field 1102a, or second coil 1103c, which may generate magnetic field 1103d, to compensate the deviated trajectory of deviated charged particle beam 1104. In some embodiments, controller 1109 may generate a converted signal based on a simulation estimation ratio as described above in FIG. 6. In some embodiments, second coil 1103c may require a smaller corrected signal compared to objective lens coil 1103a to correct the focus of deviated charged particle beam 1104. Since second coil 1103c is positioned close to objective lens coil 1103a, there may be overlap between the distribution of magnetic field 1103b and magnetic field 1103d. This may minimally impact fluctuations of a focusing effect to deviated charged particle beam 1104 and allow for simultaneous operation of objective lens coil 1103a and second coil 1103c (when a correction to a deviated chargedparticle beam is needed). Deviated charged particle beam 1104 may be compensated to impact a sample 1108 at a target location at a target focus. In some embodiments, an image collected of sample 1108 may have reduced distortion.

[0074] Reference is now made to FIG. 11C, which is an example schematic diagram illustrating a portion of an example charged particle beam apparatus 1120 for compensating a charged particle beam trajectory, consistent with embodiments of the present disclosure. FIG. 11C illustrates controller 1109 being communicatively connected to scanning deflection unit 1102 and to a magnetic 1121. In some embodiments, magnetic lens 1121 may be smaller than objective lens coil 1103a in objective lens 1103. Magnetic lens 1121 may be positioned above objective lens 1103. In some embodiments, a position of magnetic lens 1121 may be determined by simulation. In some embodiments, controller 1109 may determine a corrected electrical signal to compensate a trajectory of deviated charged particle beam 1104 compared to charged particle beam 1101. Controller 1109 may then supply the converted signal to deflection scanning unit 1102, which may generate magnetic field 1102a, or magnetic lens 1121, which may generate magnetic field 1121a, to compensate the deviated trajectory of deviated charged particle beam 1104. In some embodiments, controller 1109 may generate a converted signal based on a simulation estimation ratio as described above in FIG. 6. In some embodiments, magnetic lens 1121 may require a smaller corrected signal compared to objective lens coil 1103a to correct the focus of deviated charged particle beam 1104. Since magnetic lens 1121 may be smaller than objective lens 1103, a signal may be applied to magnetic lens 1121 to correct a trajectory of deviated charged particle beam 1104 more quickly than a signal applied to objective lens 1103. Deviated charged particle beam 1104 may be compensated faster to impact a sample 1108 at a target location at a target focus. In some embodiments, an image collected of sample 1108 may have reduced distortion.

[0075] The embodiments described in FIG. 10, FIG. 11A, FIG. 11B, and FIG. 11C may be incorporated in any combination and may be iterative. As a non-limiting example, a second characteristic may be applied to a deflection scanning unit (e.g., deflection scanning unit 1102 in FIG. 11A) to compensate a trajectory of a deviated charged particle beam. A second characteristic may also be applied to an objective lens coil (e.g., objective lens coils 1103a) to compensate a focus of a deviated charged particle beam. In some embodiments, a trajectory of the deviated charged particle beam may be shifted when correcting a focus of the deviated charged particle beam. Thus, the trajectory and focus of the deviated charged particle beam may be adjusted iteratively to move the charged particle beam back to a target location with a target focus.

[0076] In some embodiments, a trajectory component may comprise an auxiliary lens. Reference is now made to FIG. 12, which is an example schematic diagram illustrating a portion of an example charged particle beam apparatus 1200 for compensating a charged particle beam trajectory, consistent with embodiments of the present disclosure. In some embodiments, charged particle beam apparatus 1200 may emit a charged particle beam 1201. A deviation in a signal applied to a charged particlesource (not shown) from a power supply (not shown) may result in charged particle beam apparatus 1200 emitting a deviated charged particle beam 1204. A controller 1209 (e.g., controller 109, controller 809, controller 1009, or controller 1109) may determine a corrected signal and provide the corrected signal to a deflection scanning unit 1202 as described above. In some embodiments, a threshold value for the deviated signal may be a negligible value (e.g., zero or essentially zero) such that controller 1209 may continuously calculate a corrected signal to correct the deviated signal from the power supply. In some embodiments, the threshold value may be at least 0.003% of a signal target value. In some embodiments, controller 1209 may determine and provide a corrected signal to an auxiliary lens 1206. In some embodiments, auxiliary lens 1206 may be an electrostatic lens. For example, controller 1209 may apply a DC bias electrical signal to auxiliary lens, which may comprise a plurality of electrodes. When a DC bias electrical signal is applied, auxiliary lens 1206 may function as an electrostatic lens. Auxiliary lens 1206 may generate a corresponding electrostatic field 1206a that can provide a focusing effect to deviated charged particle beam 1204 to compensate for the under- focus or over-focus effects caused by a deviated signal from a power supply to a charged particle beam apparatus 1200. Since auxiliary lens 1206 is positioned close to an objective lens magnetic field 1203b, there may be overlap between the distribution of electrostatic field 1206a and the distribution of objective lens magnetic field 1203b, which may minimally impact fluctuations to deviated charged particle beam 1204 magnification and resolution. A position of auxiliary lens 1206 (e.g., relative to objective lens 1203) may be determined by simulation. Adjusting the setting of a magnetic lens may be slower than an electrostatic lens, so compensating focus with auxiliary lens 1206 instead of changing an output of objective lens 1203 (e.g., objective lens coil 1203a) may minimally impact throughput. Since auxiliary lens 1206 may function as an electrostatic lens, changing a field strength of electrostatic field 1206a may be quicker than changing a field strength of objective lens magnetic field 1203b from objective lens 1203 to compensate focus. In some embodiments, auxiliary lens 1206 may have a small inner diameter so the required electrical signal to compensate focus is lower than an electrical signal required to adjust objective lens 1203. This may help to achieve a faster focus compensation with a lower load requirement. In some embodiments, charged particle beam apparatus 1200 may comprise a second auxiliary lens (not shown), which may be positioned between objective lens 1203 and auxiliary lens 1206. The second auxiliary lens may be an electrostatic lens that is communicatively coupled to controller 1209 and second auxiliary lens may generate a corresponding electrostatic field that can also provide a focusing effect to deviated charged particle beam 1206. Deviated charged particle beam 1204 may be compensated to impact a sample 1208 at a target location at a target focus. In some embodiments, an image collected of sample 1208 may have reduced distortion.

[0077] Reference is now made to FIG. 13, which is a flowchart representing an example process for compensating for variations in charged particle beam energy in generation of an image, consistent with embodiments of the present disclosure. The steps of method 1300 may be performed by acharged particle beam system, for example, shown in FIGS. 1-12, executing on or otherwise using the features of a computing device (e.g., controller 109 of FIGS. 1 and 2, controller 503 in FIG. 5, controller 603 in FIG. 6, controller 809 in FIG. 8, controller 1009 in FIG. 10, controller 1109 in FIG. 11A, controller 1109 in FIG. 11B, and controller 1209 in FIG. 12). It is appreciated that the illustrated method 1300 may be altered to modify the order of steps and to include additional steps. The steps of method 1300 may be applicable to embodiments as illustrated in FIGS. 4, 5, 6, 7, 8, 9, 10, 11, and 12.

[0078] In step S1310, a primary charged particle beam is emitted from a charged particle source. The primary charged particle beam may be comprised of any number of charged particles.

[0079] In step SI 320, a characteristic of a first component of the charged particle system is monitored. The characteristic of the first component may affect an energy level of the primary beam of charged particles. In some embodiments, the first component of the charged particle system may be a power supply (e.g., power supply 301, 401, 501, 601, 701, or 801 of FIGS. 3, 4, 5, 6, 7, and 8) or a charged particle source (e.g., charged particle source 302, 402, 502, 602, 702, or 802 of FIGS. 3, 4, 5, 6, 7, and 8). In some embodiments, the characteristic may be an electrical signal (e.g., a voltage or a current). In some embodiments, the characteristic may be an emission current of charged particles. In some embodiments, the characteristic may be a trajectory of charged particles.

[0080] In step SI 330, a deviation from a threshold value for the characteristic of the first component is determined. A threshold value may be determined based on a percentage of a target characteristic of the first component. As a non-limiting example, a target characteristic of the first component may be a target voltage of 30 kV. The threshold value may be determined to be a 1 eV difference from the target voltage of 30 kV. Steps S1320 and S1330 may be performed by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, controller 603 in FIG. 6, controller 809 in FIG. 8, controller 1009 in FIG. 10, controller 1109 in FIG. 11A, controller 1109 in FIG. 11B, and controller 1209 in FIG. 12).

[0081] In step SI 340, a second characteristic to compensate for the deviated characteristic is calculated. In some embodiments, the second characteristic may be a compensating signal to correct the deviated characteristic to a value within the threshold. In some embodiments, the second characteristic may be an electrical signal (e.g., a voltage or a current). The second characteristic may be calculated by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, controller 603 in FIG. 6, controller 809 in FIG. 8, controller 1009 in FIG. 10, controller 1109 in FIG. 11A, controller 1109 in FIG. 11B, and controller 1209 in FIG. 12). In some embodiments, the second characteristic may be calculated by an adjustment module (e.g., adjustment module 604 in FIG. 6). In some embodiments, the second characteristic may be a converted signal to apply a compensation to an instability of a charged particle beam. In some embodiments, steps S1330 and S1340 may be performed by a digital control or digital control system.

[0082] In step SI 350, the second characteristic is applied to a second component of the charged particle system to compensate for the fluctuated charged particle beam energy. The second component may be different from the first component. In some embodiments, the second component may be a condenser lens, an objective lens, a stigmator, a microdeflector array, an auxiliary lens, a sample stage, or any other component in a charged particle system that may impact a trajectory of a charged particle beam. In some embodiments, the second component may be a separate component within a condenser lens to adjust a trajectory of a charged particle beam. In some embodiments, the second component may be an internal component of a power supply. In some embodiments, the second component may be an internal component of a charged particle source. In some embodiments, the internal component of the charged particle source may be a cathode, a suppressor, an extractor, or an anode (e.g., as in FIG. 6).

[0083] Reference is now made to FIG. 14, which is a flowchart representing an example process for compensating for variations in charged particle beam energy in generation of an image, consistent with embodiments of the present disclosure. The steps of method 1400 may be performed by a charged particle beam system, for example, shown in FIGS. 1-12, executing on or otherwise using the features of a computing device (e.g., controller 109 of FIGS. 1 and 2, controller 503 in FIG. 5, controller 603 in FIG. 6, controller 809 in FIG. 8, controller 1009 in FIG. 10, controller 1109 in FIG. 11A, controller 1109 in FIG. 11B, and controller 1209 in FIG. 12). It is appreciated that the illustrated method 1400 may be altered to modify the order of steps and to include additional steps. The steps of method 1400 may be applicable to embodiments as illustrated in FIGS. 4, 5, 6, 7, 8, 9, 10, 11, and 12.

[0084] In step S1410, a primary charged particle beam is emitted from a charged particle source. The primary charged particle beam may be comprised of any number of charged particles.

[0085] In step SI 420, a characteristic of a first component of the charged particle system is monitored. The characteristic of the first component may affect an energy level of the primary beam of charged particles. In some embodiments, the first component of the charged particle system may be a power supply (e.g., power supply 301, 401, 501, 601, 701, or 801 of FIGS. 3, 4, 5, 6, 7, and 8) or a charged particle source (e.g., charged particle source 302, 402, 502, 602, 702, or 802 of FIGS. 3, 4, 5, 6, 7, and 8). In some embodiments, the characteristic may be an electrical signal (e.g., a voltage or a current). In some embodiments, the characteristic may be an emission current of charged particles. In some embodiments, the characteristic may be a trajectory of charged particles.

[0086] In step S1430, a difference between the characteristic of the first component and a threshold value is calculated. The threshold value may be determined based on a percentage of a target characteristic of the first component. As a non-limiting example, a target characteristic of the first component may be a target voltage of 30 kV. The threshold value may be determined to be a 1 eV difference from the target voltage of 30 kV. Steps S1420 and S1480 may be performed by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, controller 603 inFIG. 6, controller 809 in FIG. 8, controller 1009 in FIG. 10, controller 1109 in FIG. 11A, controller 1109 in FIG. 11B, and controller 1209 in FIG. 12).

[0087] In step SI 440, a second characteristic to compensate for the difference between the characteristic of the first component and the threshold value is calculated. In some embodiments, the second characteristic may be a compensating signal to correct the characteristic of the first component to a value within the threshold. In some embodiments, the second characteristic may be an electrical signal (e.g., a voltage or a current). The second characteristic may be calculated by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, controller 603 in FIG. 6, controller 809 in FIG. 8, controller 1009 in FIG. 10, controller 1109 in FIG. 11A, controller 1109 in FIG. 11B, and controller 1209 in FIG. 12). In some embodiments, the second characteristic may be calculated by an adjustment module (e.g., adjustment module 604 in FIG. 6). In some embodiments, the second characteristic may be a converted signal to apply a compensation to an instability of a charged particle beam. In some embodiments, steps S1430 and S1440 may be performed by an analog control or analog control system.

[0088] In step S1450, the second characteristic is applied to a second component of the charged particle system to compensate for the fluctuated charged particle beam energy. The second component may be different from the first component. In some embodiments, the second component may be a condenser lens, an objective lens, a stigmator, a microdeflector array, an auxiliary lens, a sample stage, or any other component in a charged particle system that may impact a trajectory of a charged particle beam. In some embodiments, the second component may be a separate component within a condenser lens to adjust a trajectory of a charged particle beam. In some embodiments, the second component may be an internal component of a power supply. In some embodiments, the second component may be an internal component of a charged particle source. In some embodiments, the internal component of the charged particle source may be a cathode, a suppressor, an extractor, or an anode (e.g., as in FIG. 6).

[0089] Reference is now made to FIG. 15, which is an example schematic of a system to compensate energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure. FIG. 15 illustrates that a power supply 1501 may be communicatively coupled to a charged particle source 1502 as described above regarding FIG. 6. In some embodiments, power supply 1501 may be communicatively coupled to a charged particle source cathode 1502_l, a suppressor 1502_2, an extractor 1502_3, and a charged particle source anode 1502_4. Power supply 1501 may provide an electrical signal to charged particle source 1502 via any one of the illustrated connections to cause charged particle source 1502 to emit primary beam of charged particles 1506. In some embodiments, power supply 1501 may be communicatively coupled to a controller 1503 (e.g., controller 109), which may continuously monitor a signal supplied from power supply 1501 to charged particle source 1502. If the signal supplied from power supply 1501 exceeds a threshold value, controller 1503 may feed the deviated signal into a compensation module 1504. In someembodiments, compensation module 1504 may generate a compensated electrical signal targeting a negligible (e.g., zero or essentially zero) fluctuation in electrical signal applied to charged particle source 1502. In some embodiments, a threshold value for the deviated signal may be a negligible value (e.g., zero or essentially zero) such that controller 1503 may continuously feed the deviated signal into compensation module 1504 (e.g., a negative feedback system). In some embodiments, the threshold value may be at least 0.003% of a signal target value. In some embodiments, controller 1503 may calculate a difference between a monitored signal supplied from power supply 1501 to charged particle source 1502 and a threshold value. Controller 1503 may then calculate a second signal based on the calculated difference using compensation module 1504. The calculated second signal may be supplied to charged particle source 1502 to compensate for the difference between the monitored signal and the threshold value and target a negligible (e.g., zero or essentially zero) fluctuation in electrical signal applied to charged particle source 1502. The term “essentially zero” may be understood to mean a non-zero fluctuation in an electrical signal that does not impact an energy level of an emitted primary beam of charged particles. In some embodiments, compensation module 1504 may be an adaptive control, an automatic disturbance rejection control, a model predictive control, a proportional-integral-derivative (PID) controller, a robust control, or any other controller or module capable of controlling a system subject to changes, uncertainties, or unknowns. In some embodiments, compensation module 1504 may be a proportional-integral-derivative (PID) controller. Compensation module 1504 may output a compensated electrical signal (e.g., voltage or current), and controller 1503 may supply the compensated electrical signal back to power supply 1501 as a bias 1505. Power supply 1501 may then apply an updated signal to charged particle source 1502 based on the compensated electrical signal. In some embodiments, bias 1505 may be applied to power supply 1501 to stabilize an output signal (e.g., voltage) provided to cathode 1502_l of charged particle source 1502. In some embodiments, bias 1505 may be applied to power supply 1502 to stabilize an output signal (e.g., voltage) provided to suppressor 1502_2 of charged particle source 1502. In some embodiments, bias 1505 may be applied to power supply 1501 to stabilize an output signal (e.g., voltage) provided to extractor 1502_3 of charged particle source 1502. Stabilizing an output signal provided to cathode 1502_l, suppressor 1502_2, or extractor 1502_3 may stabilize a characteristic (e.g., emission current) of charged particle beam 1506. In some embodiments, bias 1505 may be applied to power supply 1502 to stabilize an output signal (e.g., voltage) provided to anode 1502_4. Anode 1502_4 may then adjust an accelerating voltage of charged particle source 1502. Thus, FIG. 15 may illustrate a system to continuously monitor and compensate an emission current variation of charged particle beam 1506 in real-time. It is appreciated that bias 1505 may be applied to any component of power supply 1501.

[0090] Reference is now made to FIG. 16, which is a flowchart representing an example process for compensating for variations in charged particle beam energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure. The steps of method 1600 may be performedby a charged particle beam system, for example, shown in FIGS. 2-5 and 15, executing on or otherwise using the features of a computing device (e.g., controller 109 of FIGS. 1 and 2, controller 503 in FIG. 5, and controller 1503 in FIG. 15). It is appreciated that the illustrated method 1600 may be altered to modify the order of steps and to include additional steps. The steps of method 1600 may be applicable to embodiments as illustrated in FIGs. 4, 5, and 15.

[0091] In step S 1610, a primary charged particle beam is emitted from a charged particle source. The primary charged particle beam may be comprised of any number of charged particles.

[0092] In step SI 620, a characteristic of a first component of the charged particle system is monitored. The characteristic of the first component may affect an energy level of the primary beam of charged particles. In some embodiments, the first component of the charged particle system may be a power supply (e.g., power supply 301, 401, 501, or 1501 of FIGS. 3, 4, 5, or 15) or a charged particle source (e.g., charged particle source 302, 402, 502, or 1502 of FIGS. 3, 4, 5, or 15). In some embodiments, the characteristic may be an electrical signal (e.g., a voltage or a current). In some embodiments, the characteristic may be an emission current of charged particles. In some embodiments, the characteristic may be an extractor voltage of the charged particle source. In some embodiments, the characteristic may be an accelerating voltage of the charged particle source.

[0093] In step S1630, a deviation from a threshold value for the characteristic of the first component is determined. A threshold value may be determined based on a percentage of a target characteristic of the first component. As a non-limiting example, a target characteristic of the first component may be a target voltage of 30 kV. The threshold value may be determined to be a 1 eV difference from the target voltage of 30 kV. Steps S1620 and S1630 may be performed by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, and controller 1503 in FIG. 15).

[0094] In step SI 640, a second characteristic to compensate for the deviated characteristic is calculated. In some embodiments, the second characteristic may be a compensating signal to correct the deviated characteristic to a value within the threshold. In some embodiments, the second characteristic may be an electrical signal (e.g., a voltage or a current). The second characteristic may be calculated by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, and controller 1503 in FIG. 15). In some embodiments, the second characteristic may be calculated by a compensation module (e.g., compensation module 1504 in FIG. 15). In some embodiments, the adjustment module may be a PID controller. In some embodiments, the second characteristic may be calculated to target a negligible fluctuation in electrical signal applied to the charged particle source. In some embodiments, the second characteristic may be a converted signal to apply a compensation to an instability of a charged particle beam. In some embodiments, steps S1630 and SI 640 may be performed by a digital control or a digital control system.

[0095] In step S1650, the second characteristic is applied to the power supply to compensate for the fluctuated charged particle beam energy. In some embodiments, the second characteristic may be applied to the power supply as an electrical bias. The power supply may then apply the bias to thecharged particle source. In some embodiments, the bias may be applied to an extractor of the charged particle source and adjust an extractor voltage. In some embodiments, the bias may be applied to an anode of the charged particle source to adjust an accelerating voltage.

[0096] Reference is now made to FIG. 17, which is a flowchart representing an example process for compensating for variations in charged particle beam energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure. The steps of method 1700 may be performed by a charged particle beam system, for example, shown in FIGS. 2-5 and 15, executing on or otherwise using the features of a computing device (e.g., controller 109 of FIGS. 1 and 2, controller 503 in FIG. 5, and controller 1503 in FIG. 15). It is appreciated that the illustrated method 1700 may be altered to modify the order of steps and to include additional steps. The steps of method 1700 may be applicable to embodiments as illustrated in FIGs. 4, 5, and 15.

[0097] In step S1710, a primary charged particle beam is emitted from a charged particle source. The primary charged particle beam may be comprised of any number of charged particles.

[0098] In step SI 720, a characteristic of a first component of the charged particle system is monitored. The characteristic of the first component may affect an energy level of the primary beam of charged particles. In some embodiments, the first component of the charged particle system may be a power supply (e.g., power supply 301, 401, 501, or 1501 of FIGS. 3, 4, 5, or 15) or a charged particle source (e.g., charged particle source 302, 402, 502, or 1502 of FIGS. 3, 4, 5, or 15). In some embodiments, the characteristic may be an electrical signal (e.g., a voltage or a current). In some embodiments, the characteristic may be an emission current of charged particles. In some embodiments, the characteristic may be an extractor voltage of the charged particle source. In some embodiments, the characteristic may be an accelerating voltage of the charged particle source.

[0099] In step S1730, a difference between the characteristic of the first component and a threshold value is calculated. A threshold value may be determined based on a percentage of a target characteristic of the first component. As a non-limiting example, a target characteristic of the first component may be a target voltage of 30 kV. The threshold value may be determined to be a 1 eV difference from the target voltage of 30 kV. Steps S1720 and S1730 may be performed by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, and controller 1503 in FIG. 15)

[0100] In step SI 740, a second characteristic to compensate for the difference between the characteristic of the first component and the threshold value is calculated. In some embodiments, the second characteristic may be a compensating signal to correct the deviated characteristic to a value within the threshold. In some embodiments, the second characteristic may be an electrical signal (e.g., a voltage or a current). The second characteristic may be calculated by a computing device (e.g., controller 109 in FIGS. 1 and 2, controller 503 in FIG. 5, and controller 1503 in FIG. 15). In some embodiments, the second characteristic may be calculated by a compensation module (e.g., compensation module 1504 in FIG. 15). In some embodiments, the adjustment module may be a PIDcontroller. In some embodiments, the second characteristic may be calculated to target a negligible fluctuation in electrical signal applied to the charged particle source. In some embodiments, the second characteristic may be a converted signal to apply a compensation to an instability of a charged particle beam. In some embodiments, steps S1730 and S1740 may be performed by an analog control or an analog control system.

[0101] In step S1750, the second characteristic is applied to the first component to compensate for the fluctuated charged particle beam energy. In some embodiments, the second characteristic may be applied to the first component as an electrical bias. In some embodiments, the first component is a power supply for the charged particle source. The power supply may then apply the bias to the charged particle source. In some embodiments, the first component is the charged particle source. In some embodiments, the bias may be applied to an extractor of the charged particle source and adjust an extractor voltage. In some embodiments, the bias may be applied to an anode of the charged particle source to adjust an accelerating voltage.

[0102] Reference is now made to FIG. 18A, which is an example schematic of a system to stabilize energy fluctuations in a power supply for a charged particle source, consistent with embodiments of the present disclosure. FIG. 18A illustrates a power supply 1801 and a charged particle source 1802 communicatively coupled (e.g., as described above). Power supply 1801 may comprise an output stabilizer 1803, which may stabilize an output signal from power supply 1801 to charged particle source 1802 during operation of a charged particle system. In some embodiments, output stabilizer1803 may regulate an output signal from power supply 1801 such that the output signal is within a desired threshold range.

[0103] Reference is now made to FIG. 18B, which is an example schematic of an output stabilizer (e.g., output stabilizer 1803) to regulate output fluctuations in a power supply for a charged particle source, consistent with embodiments of the present disclosure. In some embodiments, an output stabilizer may be a regulator for an electrical signal from a power supply. In some embodiments, the electrical signal may be a voltage and the output stabilizer may be a series voltage divider. FIG. 18B illustrates a power supply 1804 coupled to charged particle source 1802, and power supply 1804 comprises an output stabilizer 1805 that may form a series voltage divider. Output stabilizer 1805 may comprise two resistors in series, 1806 and 1807. An output resistance from power supply 1804 may determine an amount of an electrical signal (e.g., voltage) applied to induce a current in charged particle source 1802. In some embodiments, charged particle source 1802 may be coupled to power supply 1804 after resistor 1806 and before resistor 1807. Thus, an output resistance of power supply1804 may be represented as the following:(Eqn. 1)

[0104] 1806and ^1807 represent the resistance values of resistor 1806 and resistor 1807, respectively. During operation of a charged particle system comprising output stabilizer 1805 as illustrated in FIG. 18B, if an emitted current of charged particles from charged particle source 1802 fluctuates, then power supply 1804 may supply a fluctuated electrical signal in response. In some embodiments, the response electrical signal is a voltage. If the output resistance (Eqn. 1) is larger in value, then the response signal applied to charged particle source 1802 may be larger and induce further fluctuations and instabilities in an emitted current of charged particles. If the output resistance is reduced, then the response signal applied to charged particle source 1802 may be reduced and therefore reduce the frequency of a fluctuation or instability in an emitted current of charged particles. In some embodiments, an output resistance may be reduced by designing power supply 1804 to comprise a resistor (e.g., resistor 1806 or resistor 1807) with lower resistance and thus decreasing the output resistance. As a non-limiting example, a low resistance resistor that may be selected for embodiments of the present disclosure may be a 20 kQ resistor.

[0105] Although FIG. 18B illustrates a power supply 1804 being coupled to charged particle source 1802 and the power supply 1804 comprising a series voltage divider as output stabilizer 1805, it is appreciated that embodiments of the present disclosure are not so limited. For example, an output stabilizer may be incorporated as a voltage regulator instead of a series voltage divider. In some embodiments, the voltage regulator may be a linear voltage regulator or a switching voltage regulator.

[0106] Reference is now made to FIG. 18C, which is an example schematic of an output stabilizer to regulate output fluctuations in a power supply for a charged particle source, consistent with embodiments of the present disclosure. Conventional power supply components may exhibit a bandwidth range that cannot cover the frequency characteristics of a charged particle source. FIG. 18C illustrates an output stabilizer that may be a control loop circuit 1808 to increase a rejection ratio and bandwidth range of power supply 1801. Control loop circuit 1808 may comprise an input signal 1809, an error detector 1810, an error signal 1811, a controller 1812 (e.g., controller 109), an actuating signal 1813, a plant 1814, a feedback element 1815, a feedback signal 1816, and an output signal 1817. Control loop circuit 1808 may be designed to automatically achieve and maintain a desired output signal 1817 by comparing input signal 1809 with output signal 1817. Control loop circuit 1808 may continuously monitor output signal 1817, generated by plant 1814, via feedback element 1815. Feedback element 1815 may generate feedback signal 1816 and supply feedback signal 1816 to error detector 1810. In some embodiments, input signal 1809 may be a targeted signal for a power supply to apply to a charged particle source (e.g., a target voltage signal to supply to a charged particle source to induce a change in an emission current). In some embodiments, feedback signal 1816 may be a monitored signal generated by a power supply. In some embodiments, error detector 1810 may compare input signal 1809 and feedback signal 1816 and determine an error between the two signals. In some embodiments, error detector 1810 may determine a difference between feedback signal 1816 and input signal 1809. As a non-limiting example, input signal 1809 may be a targetvoltage signal supplied to a charged particle source (e.g., charged particle source 1802 of FIG. 18A) from a power supply (e.g., power supply 1801 of FIG. 18A). Feedback signal 1816 may be an actual voltage signal supplied to the charged particle source from the power supply. Error detector 1810 may then determine a difference between the actual voltage signal and the target voltage signal supplied to the charged particle source. Error detector 1810 may then output error signal 1811 to controller 1812. In some embodiments, error signal 1811 may be the difference between input signal 1809 and feedback signal 1816. Controller 1812 may amplify error signal 1811 to compensate and provide a correction. In some embodiments, the amplified error signal 1811 may be actuating signal 1813. Controller 1812 may thus provide a compensation to plant 1814 and stabilize output signal 1817 (e.g., reduce a fluctuation or deviation from a target value).

[0107] In some embodiments, plant 1814 may be a transformer configured to supply power to a charged particle system at high frequency. In some embodiments, plant 1814 may be a switching transformer. A switching transformer may convert an alternating current supply signal to a direct current output voltage signal. Additionally, a switching transformer may adjust an output signal (e.g., a voltage) by switching between an “on” and “off’ state. If an input signal is lower than a desired output, a switching transformer will switch to “on” and induce a signal to add to the input signal to reach the desired output. If an input signal is larger than a desired output, a switching transformer will switch to “off’ and thus decrease the signal to reach the desired value. Switching transformers operate at high frequencies (e.g., 100 kHz to 1 MHz) and switching from “on” to “off’ results in low power dissipation compared to power being delivered to a load (e.g., a charged particle source). A switching transformer exhibits a lower equivalent inductance compared to a conventionally used transformer (e.g., a linear transformer), so a switching transformer used for plant 1814 may effectively increase a bandwidth of power supply 1801 and thus compensate for a wider variation of an output signal to a charged particle source 1802.

[0108] In some embodiments, feedback element 1815 may monitor output signal 1817 at a sampling rate such that a characteristic of output signal 1817 may be determined. In some embodiments, the sample rate of feedback element 1815 is increased, and feedback element 1815 may capture data of output signal 1817 at a greater rate and obtain more information on higher frequency phenomena. For example, a higher sampling rate of feedback element 1815 may capture emission characteristics (e.g., emission current fluctuation) of a charged particle beam emitted from a charged particle source.

[0109] In some embodiments, controller 1812 may be configured to provide adjustable or adaptive compensation to an output signal. In some embodiments, controller 1812 may be a digital component. A digital controller may provide improved compensation to an output signal (e.g., output signal 1817) that has deviated from a threshold by improving identification of poles and zeros of a transfer function and thus improve modification of an input signal (e.g., input signal 1809) to obtain a desired output signal (e.g., output signal 1817). In some embodiments, the threshold value may be at least 0.003% of a signal target value. In some embodiments, a threshold value for the deviated signal may be anegligible value (e.g., zero or essentially zero) such that controller 1812 may continuously calculate and provide adjustable or adaptive compensation to an output signal (e.g., acting as a negative feedback system). In some embodiments, a digital controller may reduce noise and energy cost associated with adjusting an output signal to compensate for a fluctuation. In some embodiments, a digital controller may employ of a series of discrete pulses of signal representing either one or zero bits to transmit information, and thus may eliminate an impact of noise (e.g., electrical, or electromagnetic). Non-limiting examples of a digital controller may be an ethernet connection, RS- 232 serial, ProfiNet, DeviceNet, ControlNet, Modbus, and other forms of individual or serially connected devices that provide discrete bits of information through a single transmit or receive wire.

[0110] In some embodiments, a characteristic of a charged particle beam may be monitored (as described above) and an output signal from a power supply may be regulated by adjusting a component of control loop circuit 1808. In some embodiments, plant 1814 may be a switching transformer and a frequency of the transformer may be increased. Increasing a switching transformer frequency may increase a bandwidth of control loop circuit 1808, and therefore increase a bandwidth of the power supply. In some embodiments, an output signal from a power supply may be regulated by increasing a sampling rate of feedback element 1815. A higher sampling rate of feedback element 1815 may capture emission characteristics (e.g., emission current fluctuation) of a charged particle beam emitted from a charged particle source, so output signal 1817 of control loop circuit 1808 may more accurately correct for fluctuations of a charged particle source. In some embodiments, a threshold value for the deviated signal may be a negligible value (e.g., zero or essentially zero) such that controller 1009 may continuously calculate a corrected signal to correct the deviated signal from the power supply. In some embodiments, the threshold value may be at least 0.003% of a signal target value. Thus, an output signal provided from a power supply to a charged particle source may be stabilized.

[0111] Reference is now made to FIG. 18D, which is an example schematic of an output stabilizer to regulate output fluctuations in a power supply for a charged particle source, consistent with embodiments of the present disclosure. FIG. 18D illustrates an output stabilizer may be an output filter capacitor matrix 1820, which may reduce a fluctuation in an output signal from power supply 1801 to charged particle source 1802. In some embodiments, output filter capacitor matrix 1820 may be positioned at an output end of power supply 1801 that provides an output signal to a charged particle source 1802. In some embodiments, output filter capacitor matrix 1820 may be a capacitor matrix comprising a multi-stage series and parallel connection. In some embodiments, output filter capacitor matrix 1820 may provide high-voltage and high-capacity functionality to reduce a fluctuation in an output signal from power supply 1801 to charged particle source 1802. In some embodiments, output filter capacitor matrix 1820 reduces an equivalent impedance of power supply 1801 and thus reduces a fluctuation of an output signal to charged particle source 1802.

[0112] Reference is now made to FIG. 18E, which is an example schematic of an output stabilizer (e.g., output stabilizer 1803) to regulate output fluctuations of a power supply for a charged particle source, consistent with embodiments of the present disclosure. FIG. 18E illustrates an output stabilizer 1821 that may be incorporated within power supply 1801. In some embodiments, output stabilizer 1821 may be connected (e.g., electrically connected) to an input supply 1822 and may be connected (e.g., electrically connected) to a first output 1823, a second output 1824, a third output1825, and a fourth output 1826 of power supply 1801. Input supply 1822 may provide a signal to output stabilizer 1821, and output stabilizer 1821 may regulate a characteristic of the signal and provide the regulated signal to first output 1823, second output 1824, third output 1825, and fourth output 1826. First output 1823 may provide the regulated signal to a first component of a charged particle source (e.g., a particle source cathode), second output 1824 may provide the regulated signal to a second component of the charged particle source (e.g., a suppressor), third output 1825 may provide the regulated signal to a third component of the charged particle source (e.g., an extractor), and fourth output 186 may provide the regulated signal to a fourth component of the charged particle source (e.g., a charged particle source anode) or a sample stage. While four outputs are shown in FIG. 18E, it should be appreciated that output stabilizer 1821 may be connected to any number of outputs.

[0113] Reference is now made to FIG. 18F, which is an illustration of an exemplary configuration of output stabilizer 1821, consistent with embodiments of the present disclosure. FIG. 18F illustrates that output stabilizer 1821 comprises a low pass filter (LPF) 1827, a power supply rejection ratio (PSRR) circuit 1828, a protect 1829, and a power supply 1830 for PSRR circuit 1828. In some embodiments, LPF 1827 comprises an RC (e.g., resistor and capacitor). In some embodiments, LPF 1827 may receive an electrical signal from an input supply (e.g., input supply 1822) where the electrical signal exhibits a fluctuation. Power supply 1801 without output stabilizer 1821 outputs an electrical signal that exhibits fluctuation because of high output resistance of input supply 1822 or load current fluctuation of first output 1823, second output 1824, third output 1825, or fourth output1826. In some embodiments, the electrical signal is a voltage source. In some embodiments, the electrical signal is a -30kV voltage. LPF 1827 may filter the electrical signal such that LPF 1827 provides a filtered electrical signal to PSRR circuit 1828. In some embodiments, the electrical signal from an input supply (e.g., input supply 1822) may exhibit a fluctuation and LPF 1827 may filter the electrical signal such that the filtered electrical; signal exhibits a significantly reduced fluctuation. In some embodiments, PSRR circuit 1828 comprises an amplifier such that PSRR circuit 1828 receives the filtered electrical signal and amplifies the filtered electrical signal by providing a low output resistance. Thus, PSRR circuit 1828 may provide a stable voltage source to a load component. Power supply 1830 may provide a positive bias signal 1830a and a negative bias signal 1830b to PSRR circuit 1828 to enable the amplification. In some embodiments, positive signal 1830a is created by combining a high voltage source + an isolated DC power source (e.g., 30 kV + 24 VDC) and negative bias signal 1830b is created by combining a high voltage source - an isolated DC power source (e.g.,30kV - 24 VDC). The amplified electrical signal may then pass through protect 1829 and be provided to first output 1823, second output 1824, third output 1825, and fourth output 1826 (see FIG. 18E). In some embodiments, protect 1829 may be a combination or combinations of circuit elements that act as protection in case of a circuit fault in output stabilizer 1821. In some embodiments, protect 1829 is a circuit breaker or a fault circuit interrupter. The amplified electrical signal may be a voltage exhibiting significantly reduced fluctuation and can provide a stable voltage (e.g., with significantly reduced fluctuation) to first output 1823, second output 1824, third output 1825, and fourth output 1826. Thus, first output 1823, second output 1824, third output 1825, and fourth output 1826 can provide a more stable voltage source to the charged particle source.

[0114] In a charged particle system, a power supply (e.g., 1801) for a charged particle source (e.g., 1802) may operate at high voltage (e.g., 30 kV), so a conventional output stabilizer in a power supply needs a power supply of a similar voltage (e.g., 30 kV + / - 5) to receive and amplify a high voltage. In a conventional output stabilizer, an amplifier in a PSRR circuit is powered by significantly lower voltages (e.g., + / - 24 V input signals) and therefore is not able to amplify a received high voltage signal (e.g., 30 kV) due to the very large voltage variation (e.g., 30 kV vs. + / - 24 V). Furthermore, conventional output stabilizers have struggled to configure a PSRR circuit with a high-power supply that can handle a high voltage signal (e.g., 30 kV) because of such large voltage variations between the circuit components. Therefore, a conventional PSRR circuit is not able to regulate a fluctuation in a high voltage signal applied to a charged particle source. Thus, the charged particle source in a conventional charged particle system will emit a charged particle beam exhibiting undesirable fluctuations in energy level, emission current, trajectory, or other charged particle beam characteristics. In contrast, embodiments of the present disclosure provide output stabilizer 1821 where a node that would normally be connected to ground is floating (e.g., a floating ground) on an input for LPF 1827. In some embodiments, floating power supply 1830 on a high voltage supply (e.g., 30 kV) enables power supply 1830 to provide a positive bias signal 1830a and a negative bias signal 1830b based on a high voltage input signal (e.g., 30 kV) to PSRR circuit 1830. In some embodiments, positive bias signal 1830a is 30 kV + 8 and negative bias signal 1830b is 30 kV - 8. Therefore, the amplifier in PSRR circuit 1828 may receive an amplify a large signal (e.g., a 30 kV signal) while being powered by a low DC voltage power source (e.g., 24 VDC). While a 30 kV signal is used in this description, it should be appreciated that the technique of this disclosure can work with any high voltage signal.

[0115] Reference is now made to FIG. 18G, which is an illustration of an exemplary configuration of an output stabilizer (e.g., output stabilizer 1821), consistent with embodiments of the present disclosure. FIG. 18G illustrates example electrical circuits in PSRR circuit 1828 and power supply 1830. It is appreciated that the electrical circuits illustrated in FIG. 18G are for illustrative purposes only, and do not represent an entire electrical circuit for either PSRR circuit 1828 or power supply 1830. For example, the boxes containing “...” in power supply 1830 represent that more circuitfeatures may be present. In some embodiments, the boxes containing “...” in power supply 1830 may represent inductors, capacitors, diodes, or any other circuit element in an isolated DC / DC power supply configured to provide a positive bias and negative bias to a high voltage power supply. In some embodiments, power supply 1830 is powered by a DC power supply 1834. In some embodiments, DC power supply 1834 is a 24 VDC power supply. Input supply 1822 may output a signal (e.g., a 30 kV signal) to LPF 1827, which filters the electrical signal and provides the filtered electrical signal to PSRR 1828. As illustrated in FIG. 18G, PSRR 1828 comprises an amplifier 1831, which is powered by power supply 1830. Power supply 1830 supplies a positive bias signal and a negative bias signal to amplifier 1831. Terminal 1830a may be connected to terminal 1831a, in which the negative bias signal is applied to amplifier 1831. Terminal 1830b may be connected to terminal 1831b, in which the positive bias signal is applied to amplifier 1831. In a conventional output stabilizer, a power supply may be powered by an external low voltage source (e.g., 24 V). Therefore, a conventional power supply provides a +24 V bias signal and a -24 V bias signal to an amplifier in a PSRR circuit. However, the PSRR circuit needs to amplify a significantly larger voltage: such as 30 kV. Therefore, a conventional PSRR circuit is not capable of amplifying a 30 kV signal and cannot be used to reduce an electrical signal fluctuation. Embodiments of the present disclosure, as illustrated in FIG. 18G, provide a circuit that enables PSRR circuit 1828 to amplify a large electrical signal (e.g., a 30 kV signal). Power supply 1830 may instead be configured to float (e.g., a floating ground) on the output line from input supply 1822 to LPF 1827. In some embodiments, a grounding node of power supply 1830 is connected to input supply 1822, as illustrated in FIG. 18G by dotted line 1833.Therefore, power supply 1830 has a reference point of 30 kV and determines the positive bias and negative bias signals from this new reference point (e.g., 30 kV + 5 and 30 kV - 5). Accordingly, power supply 1830 may provide a 30 kV + 8 bias signal to amplifier 1831 via the connection between terminal 1830b and terminal 1831b and may provide a 30 kV - 8 bias signal to amplifier 1831 via the connection between terminal 1830a and terminal 1831a. In some embodiments, power supply 1830 may provide a 30 kV + 24 V bias signal and a 30 kV - 24 V bias signal to amplifier 1831. Amplifier 1831 therefore may have sufficient power to receive and amplify a large electrical signal (e.g., a 30 kV signal). The amplified electrical signal may pass through protect 1829 and be provided to a load component 1832 (e.g., first output 1823, second output 1824, third output 1825, and fourth output 1826 as described above). In some embodiments, power supply 1830 may be connected to ground for a low voltage operation (e.g., < 1.5 kV) of PSRR circuit 1828.

[0116] In some embodiments, an output stabilizer may be located outside of power supply 1801 or between power supply 1801 and charged particle source 1802. Reference is now made to FIG. 18H, which illustrates an output stabilizer module 1835 comprising a plurality of output stabilizers located outside of a power supply for a charged particle source, consistent with embodiments of the present disclosure. As described above, power supply 1801 may be a high voltage power supply, and may provide a high voltage signal (e.g., 30 kV) to first output 1823, second output 1824, third output 1825,and fourth output 1826, and outputs 1823-1826 may each supply an electrical signal (e.g., a current signal) to a charged particle source or a component of a charged particle system (e.g., a sample stage). FIG. 18H illustrates output stabilizer module 1835 may comprise output stabilizers 1836-1838 on each output line from outputs 1824-1826 to the charged particle source or a component of the charged particle system. Output stabilizers 1836-1838 may be as described above and illustrated in FIG. 18F or FIG. 18G. Accordingly, output stabilizers 1836-1838 may reduce a fluctuation in an electrical signal from outputs 1824-1826 to the charged particle source or a component of the charged particle system, and power supply 1801 may remain unchanged. In some embodiments, first output 1823 comprises two output lines that may output a larger electrical signal (e.g., a current signal) compared to outputs 1824-1826. In some embodiments, output stabilizer module 1835 may stabilize an average voltage of the two output lines from first output 1823. Therefore, output stabilizer module 1835 may comprise converter 1839 to convert the current signal to a voltage signal, and then supply the converted voltage signal to controllable current source 1840. A LPF 1841 may also be communicatively connected (e.g., electrically connected) to first output 1823 and may provide a filtered electrical signal to controllable current source 1840. In some embodiments, controllable current source 1840 may be powered by power source 1842, as described above with respect to a PSRR circuit. In some embodiments, controllable current source 1840 may output an electrical signal with reduced fluctuation, which may pass through protect 1843, and be provided to a charged particle source 1802. In some embodiments, output stabilizers 1836-1838 provide an electrical signal with reduced fluctuation to charged particle source 1802 or to a component that impacts a trajectory of an emitted primary beam of charged particles.

[0117] Reference is now made to FIG. 19, which is an example illustration of a capacitor matrix to regulate output fluctuations in a first component in a charged particle source, consistent with embodiments of the present disclosure. FIG. 19 illustrates a first component 1901 of a charged particle system with a capacitor matrix 1902 located at an output end of the first component 1901. Output signal 1903 from first component 1901 may be supplied to capacitor matrix 1902 and regulated output signal 1904 may be supplied from capacitor matrix 1902 and as output from first component 1901. Capacitor matrix 1902 may comprise a combination of series and parallel capacitors to facilitate a higher voltage and higher capacitance capacity. FIG. 19 illustrates capacitor matrix 1902 may include a first series of capacitors comprising capacitor Cl 1, capacitor C12, and capacitor C13, a second series of capacitors comprising capacitor C21, capacitor C22, and capacitor C23, and a third series of capacitors comprising C31, capacitor C32, and capacitor C33. Additionally, capacitors Cl l, C21, and C31 are connected in parallel in capacitor matrix 1902, as are capacitors C12, C22, C32, and C13, C23, and C33. It is appreciated that any number of capacitors may be connected in series or parallel in capacitor matrix 1302 and embodiments of the present disclosure are not limited as illustrated in FIG. 19. In some embodiments, first component 1901 may be a power supply and regulated output signal 1904 may be supplied to a charged particle source.

[0118] Reference is now made to FIG. 20, which is a flowchart representing an example process for compensating for variations in charged particle beam energy fluctuations in a charged particle source, consistent with embodiments of the present disclosure. The steps of method 2000 may be performed by a charged particle beam system, for example, shown in FIGS. 2-5, 9, 18A, 18B, 18C, 18D, and 19, executing on or otherwise using the features of a computing device (e.g., controller 109 of FIGS. 1 and 2, controller 503 in FIG. 5, controller 1503 in FIG. 15, and controller 1812 in FIG. 18C). It is appreciated that the illustrated method 2000 may be altered to modify the order of steps and to include additional steps. The steps of method 2000 may be applicable to embodiments as illustrated in FIGs. 4, 5, 15, 18A, 18B, 18C, 18D, 18E, 18F, 18G, 18H, and 19.

[0119] In step S2010, a primary charged particle beam is emitted from a charged particle source. The primary charged particle beam may be comprised of any number of charged particles.

[0120] In step S2020, a characteristic of the charged particle source is monitored. In some embodiments, the characteristic of the charged particle source may be an emission current of charged particles. In some embodiments, the characteristic may be an extractor voltage of the charged particle source. In some embodiments, the characteristic may be an accelerating voltage of the charged particle source. In some embodiments, the characteristic of the charged particle source may be monitored directly via the charged particle source. In some embodiments, the characteristic of the charged particle source may be monitored indirectly. In some embodiments, the characteristic of the charged particle source may be monitored by monitoring the primary beam of charged particles.

[0121] In step S2030, a characteristic of a first component of the charged particle source is regulated based on the monitored characteristic of the charged particle source. The characteristic of the first component may affect an energy level of the primary beam of charged particles. In some embodiments, the first component of the charged particle system may be a power supply (e.g., power supply 301, 401, 501, 1501, 1801, 1804, or 1901 of FIGS. 3, 4, 5, 15, 18A, 18B, 18D, or 19) or a charged particle source (e.g., charged particle source 302, 402, 502, 1502, or 1802 of FIGS. 3, 4, 5, 15, 18A, 18B, or 18D). In some embodiments, the characteristic may be an electrical signal (e.g., a voltage or a current). In some embodiments, the characteristic may be an emission current of charged particles. In some embodiments, the characteristic may be an extractor voltage of the charged particle source. In some embodiments, the characteristic may be an accelerating voltage of the charged particle source.

[0122] In some embodiments, the characteristic of the first component is regulated by reducing an output characteristic of the first component of the charged particle system. The first component of the charged particle system may be a power supply for the charged particle source. In some embodiments, the output characteristic is an output resistance. In some embodiments, a series voltage divider (e.g., voltage divider 1805 of FIG. 18B) may be used to reduce the output resistance of the first component of the charged particle system.

[0123] In some embodiments, the characteristic of the first component is regulated by increasing a second characteristic of the first component of the charged particle system, wherein the first component comprises a control loop (e.g., control loop circuit 1808 of FIG. 18C). The first component may be a power supply of the charged particle source. In some embodiments, the second characteristic is a bandwidth range of the first component. In some embodiments, the control loop comprises a high frequency transformer (e.g., plant 1814 of FIG. 18C), a feedback element with an increased sampling rate (e.g., feedback element 1815 of FIG. 18C), or a digital controller (e.g., controller 1812 of FIG. 18C). In some embodiments, the high frequency transformer is a switching transformer.

[0124] In some embodiments, the characteristic of the first component is regulated by using a capacitor matrix (e.g., capacitor matrix 1820 of FIG. 18D or capacitor matrix 1902 of FIG. 19) to reduce a fluctuation of the characteristic of the first component. The first component may be a power supply of the charged particle source. In some embodiments, the capacitor matrix may withstand a higher voltage and maintain a larger capacitance. In some embodiments, the capacitor matrix may comprise a combination of series capacitors (e.g., capacitors Cl l, C12, and C13 of FIG. 19) and parallel capacitors (e.g., capacitors Cl l, C21, and C31 of FIG. 19).

[0125] In step S2040, the regulated characteristic is applied to the charged particle source to compensate for the monitored characteristic of the charged particle source. In some embodiments, the regulated characteristic may be applied to the charged particle source as an electrical bias. In some embodiments, the bias may be applied to an extractor of the charged particle source and adjust an extractor voltage. In some embodiments, the bias may be applied to an anode of the charged particle source to adjust an accelerating voltage.

[0126] Reference is now made to FIGS. 21A and 21B, which are example illustrations of an uncompensated versus compensated fluctuation of an output signal from a power supply to a charged particle source, consistent with embodiments of the present disclosure. FIG. 21A illustrates an uncompensated fluctuation of an output signal 2101 over time 2102 and FIG. 21B illustrates a compensated fluctuation of a compensated output signal 2103 over time 2102. Compensated output signal 2103 may be obtained via embodiments described above. Output signal 2101 fluctuates past a threshold 2104 for a significant portion of time 2102 in FIG. 21A. Threshold 2104 may indicate a range of uncompensated output signal 2101 that may not induce an instability in a charged particle source, or a charged particle beam emitted from the charged particle source. Thus, FIG. 21A illustrates uncompensated output signal 2101 may induce an instability in a charged particle system. In comparison, compensated output signal 2103 in FIG. 21B remains within threshold 2104. Thus, FIG. 21B illustrates that compensated output signal 2103 may avoid an instability in a charged particle system and maintain satisfactory control over charged particle source stability, noise, image quality, and other performance issues of a charged particle system related to charged particle energy fluctuations.

[0127] A non-transitory computer readable medium may be provided that may store instructions for a processor of a controller (e.g., controller 109 of FIGS. 1 and 2, controller 503 of FIG. 5, controller 603 of FIG. 6, controller 809 in FIG. 8, controller 1009 in FIG. 10, controller 1109 in FIG. 11A, controller 1109 in FIG. 11B, controller 1209 in FIG. 12, controller 1503 in FIG. 15, or controller 1812 in FIG. 18C) to perform inspection image acquisition, activating charged particle source, method 1300, method 1400, method 1600, method 1700, method 2000, and other executable functions in the charged particle system relating to compensating for variations in charged particle beam energy fluctuations, variations in a power supply, and variations in a charged particle source. Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a Compact Disc Read Only Memory (CD-ROM), any other optical data storage medium, any physical medium with patterns of holes, a Random Access Memory (RAM), a Programmable Read Only Memory (PROM), and Erasable Programmable Read Only Memory (EPROM), a FLASH-EPROM or any other flash memory, Non-Volatile Random Access Memory (NVRAM), a cache, a register, any other memory chip or cartridge, and networked versions of the same.

[0128] The embodiments may further be described using the following clauses:1. A method of compensating for variations in charged particle beam system, comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; determining whether the first characteristic of the first component has deviated from a target value by more than a threshold value; in response to a determination that the first characteristic has deviated from the target value by more than the threshold value, calculating a second characteristic to compensate for the deviated characteristic; and applying the second characteristic to a second component that affects an energy level of the primary beam of charged particles, wherein the second component is different from the first component.2. The method of clause 1, wherein the first characteristic of the first component is a value of an electrical signal.3. The method of clause 2, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.4. The method of any one of clauses 1 to 3, wherein the second characteristic is a value of an electrical signal.5. The method of clause 4, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.6. The method of any one of clauses 1 to 5, wherein the first component of the charged particle system is a power supply for the charged particle source.7. The method of clause 6, wherein the power supply is a high voltage supply.8. The method of any one of clauses 1 to 5, wherein the first component is the charged particle source.9. The method of clause 8, wherein the first characteristic of the first component is a value of an emission current of the primary beam of charged particles.10. The method of any one of clauses 1 to 9, wherein the second component affects a trajectory of the primary beam of charged particles.11. The method of clause 10, wherein the second component is a condenser lens, a stigmator, a micro-deflector array, a deflection scanning unit, an auxiliary lens, a sample stage, or an objective lens.12. The method of any one of clause 1 to 10, wherein the second component is a component of the charged particle source.13. The method of clause 12, wherein the second component is a charged particle source cathode, a suppressor, an extractor, or an anode.14. The method of any one of clauses 1 to 13, wherein calculating the second characteristic further comprises: determining a deviation from a target position of the primary beam of charged particles impacting a sample; and converting the first characteristic to the second characteristic based on a simulation estimation ratio, wherein the second characteristic is a value of a signal compatible with the second component.15. The method of any one of clauses 1 to 14, wherein applying the second characteristic to the second component compensates for the deviation of the first characteristic.16. The method of any one of clauses 1 to 15, wherein a trajectory of the primary beam of charged particles is compensated.17. The method of any one of clauses 1 to 16, further comprising: collecting an image of a sample of interest.18. The method of any one of clauses 1 to 17, wherein the charged particle system is an optical microscope.19. The method of any one of clauses 1 to 17, wherein the charged particle system is a scanning electron microscope.20. A method of compensating for variations in charged particle beam system, comprising:causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; calculating a difference between the first characteristic of the first component and a target value; calculating a second characteristic to compensate for the difference between the first characteristic of the first component and the target value; and applying the second characteristic to a second component that affects an energy level of the primary beam of charged particles, wherein the second component is different from the first component.21. The method of clause 20, wherein the first characteristic of the first component is a value of an electrical signal.22. The method of clause 21, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.23. The method of any one of clauses 20 to 22, wherein the second characteristic is a value of an electrical signal.24. The method of clause 23, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.25. The method of any one of clauses 20 to 24, wherein the first component of the charged particle system is a power supply for the charged particle source.26. The method of clause 25, wherein the power supply is a high voltage supply.27. The method of any one of clauses 20 to 24, wherein the first component is the charged particle source.28. The method of clause 27, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.29. The method of any one of clauses 20 to 28, wherein the second component affects a trajectory of the primary beam of charged particles.30. The method of clause 29, wherein the second component is a condenser lens, a stigmator, a micro-deflector array, a deflection scanning unit, an auxiliary lens, a sample stage, or an objective lens.31. The method of any one of clauses 20 to 29, wherein the second component is a component of the charged particle source.32. The method of clause 31, wherein the second component is a charged particle source cathode, a suppressor, an extractor, or an anode.33. The method of any one of clauses 20 to 32, wherein calculating the second characteristic further comprises: determining a deviation from a target position of the charged particle beam impacting a sample; and converting the first characteristic to the second characteristic based on a simulation estimation ratio, wherein the second characteristic is a value of a signal compatible with the second component.34. The method of any one of clauses 20 to 33, wherein applying the second characteristic to the second component compensates for the difference between the first characteristic and the target value.35. The method of any one of clauses 20 to 34, wherein a trajectory of the primary beam of charged particles is compensated.36. The method of any one of clauses 20 to 35, further comprising: collecting an image of a sample of interest.37. The method of any one of clauses 20 to 36, wherein the charged particle system is an optical microscope.38. The method of any one of clauses 20 to 36, wherein the charged particle system is a scanning electron microscope.39. A charged particle system, comprising: one or more processors configured to execute instructions to cause the charged particle system to perform operations comprising: causing a charged particle source to emit a primary beam of charged particles; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; determining whether the first characteristic of the first component has deviated from a target value by more than a threshold value; in response to a determination that the first characteristic of the first component has deviated from the target value by more than the threshold value, calculating a second characteristic to compensate for the first characteristic of the first component; and applying the second characteristic to a second component that affects an energy level of the primary beam of charged particles, wherein the second component is different from the first component.40. The charged particle system of clause 39, wherein the first characteristic of the first component is a value of an electrical signal.41. The charged particle system of clause 40, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.42. The charged particle system of any one of clauses 39 to 41, wherein the second characteristic is a value of an electrical signal.43. The charged particle system of clause 42, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.44. The charged particle system of any one of clauses 39 to 43, wherein the first component of the charged particle system is a power supply for the charged particle source.45. The charged particle system of clause 44, wherein the power supply is a high voltage supply.46. The charged particle system of any one of clauses 39 to 43, wherein the first component is the charged particle source.47. The charged particle system of clause 46, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.48. The charged particle system of any one of clauses 39 to 47, wherein the second component affects a trajectory of the primary beam of charged particles.49. The charged particle system of clause 48, wherein the second component is a condenser lens, a stigmator, a micro-deflector array, a deflection scanning unit, an auxiliary lens, a sample stage, or an objective lens.50. The charged particle system of any one of clauses 39 to 48, wherein the second component is a component of the charged particle source.51. The charged particle system of clause 50, wherein the second component is a charged particle source cathode, a suppressor, an extractor, or an anode.52. The charged particle system of any one of clauses 39 to 51, wherein the operations for calculating the second characteristic further comprise: determining a deviation from a target position of the charged particle beam impacting a sample; and converting the first characteristic to the second characteristic based on a simulation estimation ratio, wherein the second characteristic is a value of a signal compatible with the second component.53. The charged particle system of any one of clauses 39 to 52, wherein the operations for applying the second characteristic to the second component compensate for the deviation of the first characteristic.54. The charged particle system of any one of clauses 39 to 53, wherein a trajectory of the primary beam of charged particles is compensated.55. The charged particle system of any one of clauses 39 to 54, wherein the operations further comprise: collecting an image of a sample of interest.56. The charged particle system of any one of clauses 39 to 56, wherein the charged particle system is an optical microscope.57. The charged particle system of any one of clauses 39 to 55, wherein the charged particle system is a scanning electron microscope.58. A charged particle system, comprising: one or more processors configured to execute instructions to cause the charged particle system to perform operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; calculating a difference between the first characteristic of the first component and a target value; calculating a second characteristic to compensate for the difference between the first characteristic of the first component and the target value; and applying the second characteristic to a second component that affects an energy level of the primary beam of charged particles, wherein the second component is different from the first component.59. The charged particle system of clause 58, wherein the first characteristic of the first component is a value of an electrical signal.60. The charged particle system of clause 59, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.61. The charged particle system of any one of clauses 58 to 60, wherein the second characteristic is a value of an electrical signal.62. The charged particle system of clause 61, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.63. The charged particle system of any one of clauses 58 to 62, wherein the first component of the charged particle system is a power supply for the charged particle source.64. The charged particle system of clause 63, wherein the power supply is a high voltage supply.65. The charged particle system of any one of clauses 58 to 62, wherein the first component is the charged particle source.66. The charged particle system of clause 65, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.67. The charged particle system of any one of clauses 58 to 66, wherein the second component affects a trajectory of the primary beam of charged particles.68. The charged particle system of clause 67, wherein the second component is a condenser lens, a stigmator, a micro-deflector array, a deflection scanning unit, an auxiliary lens, a sample stage, or an objective lens.69. The charged particle system of any one of clauses 58 to 67, wherein the second component is a component of the charged particle source.70. The charged particle system of clause 69, wherein the second component is a charged particle source cathode, a suppressor, an extractor, or an anode.71. The charged particle system of any one of clauses 58 to 70, wherein the operations for calculating the second characteristic further comprise: calculating a deviation from a target position of the charged particle beam impacting a sample; and converting the deviated first characteristic to the second characteristic based on a simulation estimation ratio, wherein the second characteristic is a value of a signal compatible with the second component.72. The charged particle system of any one of clauses 58 to 71, wherein the operations for applying the second characteristic to the second component compensate for the first characteristic.73. The charged particle system of any one of clauses 58 to 72, wherein a trajectory of the primary beam of charged particles is compensated.74. The charged particle system of any one of clauses 58 to 73, wherein the operations further comprise: collecting an image of a sample of interest.75. The charged particle system of any one of clauses 58 to 74, wherein the charged particle system is an optical microscope.76. The charged particle system of any one of clauses 58 to 74, wherein the charged particle system is a scanning electron microscope.77. A non-transitory computer readable medium comprising a set of instructions that is executable by one or more processors of a computing device to cause the computing device to perform operations for compensating for variations in charged particle beam system, the operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the characteristic of the first component affects an energy level of the primary beam of charged particles; determining whether the first characteristic of the first component has deviated from a target value by more than a threshold value;in response to a determination that the first characteristic of the first component has deviated from the target value by more than the threshold value, calculating a second characteristic to compensate for the first characteristic; and applying the second characteristic to a second component that affects an energy level of the primary beam of charged particles, wherein the second component is different from the first component.78. The non-transitory computer readable medium of clause 77, wherein the first characteristic of the first component is a value of an electrical signal.79. The non-transitory computer readable medium of clause 78, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.80. The non-transitory computer readable medium of any one of clauses 77 to 79, wherein the second characteristic is a value of an electrical signal.81. The non-transitory computer readable medium of clause 80, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.82. The non-transitory computer readable medium of any one of clauses 77 to 81, wherein the first component of the charged particle system is a power supply for the charged particle source.83. The non-transitory computer readable medium of clause 82, wherein the power supply is a high voltage supply.84. The non-transitory computer readable medium of any one of clauses 77 to 81, wherein the first component is the charged particle source.85. The non-transitory computer readable medium of clause 84, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.86. The non-transitory computer readable medium of any one of clauses 77 to 85, wherein the second component affects a trajectory of the primary beam of charged particles.87. The non-transitory computer readable medium of clause 86, wherein the second component is a condenser lens, a stigmator, a micro-deflector array, a deflection scanning unit, an auxiliary lens, a sample stage, or an objective lens.88. The non-transitory computer readable medium of any one of clauses 77 to 86, wherein the second component is a component of the charged particle source.89. The non-transitory computer readable medium of clause 88, wherein the second component is a charged particle source cathode, a suppressor, an extractor, or an anode.90. The non-transitory computer readable medium of any one of clauses 77 to 89, wherein calculating the second characteristic further comprises: determining a deviation from a target position of the charged particle beam impacting a sample; andconverting the first characteristic to the second characteristic based on a simulation estimation ratio, wherein the second characteristic is a value of a signal compatible with the second component.91. The non-transitory computer readable medium of any one of clauses 77 to 90, wherein applying the second characteristic to the second component compensates for the deviation of the first characteristic.92. The non-transitory computer readable medium of any one of clauses 77 to 91, wherein a trajectory of the primary beam of charged particles is compensated.93. The non-transitory computer readable medium of any one of clauses 77 to 92, the operations further comprising: collecting an image of a sample of interest.94. The non-transitory computer readable medium of any one of clauses 77 to 93, wherein the charged particle system is an optical microscope.95. The non-transitory computer readable medium of any one of clauses 77 to 93, wherein the charged particle system is a scanning electron microscope.96. A non-transitory computer readable medium comprising a set of instructions that is executable by one or more processors of a computing device to cause the computing device to perform operations for compensating for variations in a charged particle beam system, the operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; calculating a difference between the first characteristic of the first component and a target value; calculating a second characteristic to compensate for the difference between the first characteristic of the first component and the target value; and applying the second characteristic to a second component that affects an energy level of the primary beam of charged particles, wherein the second component is different from the first component.97. The non-transitory computer readable medium of clause 96, wherein the characteristic of the first component is a value of an electrical signal.98. The non-transitory computer readable medium of clause 97, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.99. The non-transitory computer readable medium of any one of clauses 96 to 98, wherein the second characteristic is a value of an electrical signal.100. The non- transitory computer readable medium of clause 99, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.101. The non-transitory computer readable medium of any one of clauses 96 to 100, wherein the first component of the charged particle system is a power supply for the charged particle source.102. The non-transitory computer readable medium of clause 101, wherein the power supply is a high voltage supply.103. The non-transitory computer readable medium of any one of clauses 96 to 100, wherein the first component is the charged particle source.104. The non-transitory computer readable medium of clause 103, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.105. The non-transitory computer readable medium of any one of clauses 96 to 104, wherein the second component affects a trajectory of the primary beam of charged particles.106. The non-transitory computer readable medium of clause 105, wherein the second component is a condenser lens, a stigmator, a micro-deflector array, a deflection scanning unit, an auxiliary lens, a sample stage, or an objective lens.107. The non-transitory computer readable medium of any one of clauses 96 to 105, wherein the second component is a component of the charged particle source.108. The non-transitory computer readable medium of clause 107, wherein the second component is a charged particle source cathode, a suppressor, an extractor, or an anode.109. The non-transitory computer readable medium of any one of clauses 96 to 108, wherein calculating the second characteristic further comprises: determining a deviation from a target position of the charged particle beam impacting a sample; and converting the first characteristic to the second characteristic based on a simulation estimation ratio, wherein the second characteristic is a value of a signal compatible with the second component.110. The non-transitory computer readable medium of any one of clauses 96 to 109, wherein applying the second characteristic to the second component compensates for the deviation of the first characteristic.111. The non-transitory computer readable medium of any one of clauses 96 to 110, wherein a trajectory of the primary beam of charged particles is compensated.112. The non-transitory computer readable medium of any one of clauses 96 to 111, the operations further comprising: collecting an image of a sample of interest.113. The non-transitory computer readable medium of any one of clauses 96 to 112, wherein the charged particle system is an optical microscope.114. The non-transitory computer readable medium of any one of clauses 96 to 112, wherein the charged particle system is a scanning electron microscope.115. A method of compensating for variations in charged particle beam system, comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; determining whether the first characteristic of the first component has deviated from a target value by more than a threshold value; in response to a determination that the first characteristic of the first component has deviated from the target value by more than the threshold value, calculating a second characteristic to compensate for the first characteristic; and applying the second characteristic to the first component.116. The method of clause 115, wherein the first characteristic of the first component is a value of an electrical signal.117. The method of clause 116, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.118. The method of any one of clauses 115 to 117, wherein the second characteristic is a value of an electrical signal.119. The method of clause 118, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.120. The method of any one of clauses 115 to 118, wherein the first component of the charged particle system is a power supply for the charged particle source.121. The method of clause 120, wherein the power supply is a high voltage supply.122. The method of any one of clauses 115 to 119, wherein the first component is the charged particle source.123. The method of clause 122, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.124. The method of any one of clauses 115 to 123, wherein calculating the second characteristic further comprises: using a controller to convert the first characteristic to the second characteristic, wherein the controller targets a zero or essentially zero deviation of the first characteristic from the target value.125. The method of clause 124, wherein the controller is a proportional-integral derivative (PID) controller, an adaptive control, an automatic disturbance rejection control, a model predictive control, or a robust control.126. The method of any one of clauses 115 to 125, wherein applying the second characteristic to the first component further comprises: applying the second characteristic to a component of the charged particle source.127. The method of clause 126, wherein the component of the charged particle source is a cathode, a suppressor, an extractor, or an anode.128. The method of any one of clauses 115 to 125, wherein applying the second characteristic to the first component further comprises: applying the second characteristic to a component of a power supply of the charged particle source.129. The method of clause 128, wherein the component of the power supply is communicatively connected to the charged particle source.130. The method of clause 129, wherein the component of the power supply is communicatively connected to a cathode, a suppressor, an extractor, or an anode of the charged particle source.131. The method of any one of clauses 115 to 130, wherein applying the second characteristic to the first component compensates for the deviation of the first characteristic.132. The method of any one of clauses 115 to 131, wherein a trajectory of the primary beam of charged particles is compensated.133. The method of any one of clauses 115 to 132, further comprising: collecting an image of a sample of interest.134. The method of any one of clauses 115 to 133, wherein the charged particle system is an optical microscope.135. The method of any one of clauses 115 to 133, wherein the charged particle system is a scanning electron microscope.136. A method of compensating for variations in charged particle beam system, comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; calculating a difference between the first characteristic of the first component and a target value; calculating a second characteristic to compensate for the difference between the first characteristic of the first component and the target value; and applying the second characteristic to the first component.137. The method of clause 136, wherein the characteristic of the first component is a value of an electrical signal.138. The method of clause 137, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.139. The method of any one of clauses 136 to 138, wherein the second characteristic is a value of an electrical signal.140. The method of clause 139, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.141. The method of any one of clauses 136 to 140, wherein the first component of the charged particle system is a power supply for the charged particle source.142. The method of clause 141, wherein the power supply is a high voltage supply.143. The method of any one of clauses 136 to 140, wherein the first component is the charged particle source.144. The method of clause 143, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.145. The method of any one of clauses 136 to 144, wherein calculating the second characteristic further comprises: using a controller to convert the difference between the first characteristic of the first component and the target value to the second characteristic.146. The method of clause 145, wherein the controller is a proportional-integral derivative (PID) controller, an adaptive control, an automatic disturbance rejection control, a model predictive control, or a robust control.147. The method of any one of clauses 136 to 146, wherein applying the second characteristic to the first component further comprises: applying the second characteristic to a component of the charged particle source.148. The method of clause 147, wherein the component of the charged particle source is a cathode, a suppressor, an extractor, or an anode.149. The method of any one of clauses 136 to 146, wherein applying the second characteristic to the first component further comprises: applying the second characteristic to a component of a power supply of the charged particle source.150. The method of clause 149, wherein the component of the power supply is communicatively connected to the charged particle source.151. The method of clause 150, wherein the component of the power supply is communicatively connected to a cathode, a suppressor, an extractor, or an anode of the charged particle source.152. The method of any one of clauses 136 to 151, wherein applying the second characteristic to the first component compensates for the difference between the first characteristic of the first component and the target value.153. The method of any one of clauses 136 to 152, wherein a trajectory of the primary beam of charged particles is compensated.154. The method of any one of clauses 136 to 153, further comprising: collecting an image of a sample of interest.155. The method of any one of clauses 136 to 154, wherein the charged particle system is an optical microscope.156. The method of any one of clauses 136 to 154, wherein the charged particle system is a scanning electron microscope.157. A charged particle system, comprising: one or more processors configured to execute instructions to cause the charged particle beam system to perform operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; determining whether the first characteristic of the first component has deviated from a target value by more than a threshold value; in response to a determination that the first characteristic of the first component has deviated from the target value by more than the threshold value, calculating a second characteristic to compensate for the first characteristic; and applying the second characteristic to the first component.158. The charged particle system of clause 157, wherein the first characteristic of the first component is a value of an electrical signal.159. The charged particle system of clause 158, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.160. The charged particle system of any one of clauses 157 to 159, wherein the second characteristic is a value of an electrical signal.161. The charged particle system of clause 160, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.162. The charged particle system of any one of clauses 157 to 161, wherein the first component of the charged particle system is a power supply for the charged particle source.163. The charged particle system of clause 162, wherein the power supply is a high voltage supply.164. The charged particle system of any one of clauses 157 to 161, wherein the first component is the charged particle source.165. The charged particle system of clause 164, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.166. The charged particle system of any one of clauses 157 to 165, wherein the operations for calculating the second characteristic further comprise: using a controller to convert the first characteristic to the second characteristic, wherein converting the first characteristic to the second characteristic targets a zero or essentially zero deviation from the target value.167. The charged particle system of clause 166, wherein the controller is a proportionalintegral derivative (PID) controller, an adaptive control, an automatic disturbance rejection control, a model predictive control, or a robust control.168. The charged particle system of any one of clauses 157 to 167, wherein the operations for applying the second characteristic to the first component further comprise: applying the second characteristic to a component of the charged particle source.169. The charged particle system of clause 168, wherein the component of the charged particle source is a cathode, a suppressor, an extractor, or an anode.170. The charged particle system of any one of clauses 157 to 167, wherein the operations for applying the second characteristic to the first component further comprise: applying the second characteristic to a component of a power supply of the charged particle source.171. The charged particle system of clause 170, wherein the component of the power supply is communicatively connected to the charged particle source.172. The charged particle system of clause 171, wherein the component of the power supply is communicatively connected to a cathode, a suppressor, an extractor, or an anode of the charged particle source.173. The charged particle system of any one of clauses 157 to 172, wherein applying the second characteristic to the first component compensates for the first characteristic.174. The charged particle system of any one of clauses 157 to 173, wherein a trajectory of the primary beam of charged particles is compensated.175. The charged particle system of any one of clauses 157 to 174, the operations further comprising: collecting an image of a sample of interest.176. The charged particle system of any one of clauses 157 to 175, wherein the charged particle system is an optical microscope.177. The charged particle system of any one of clauses 157 to 175, wherein the charged particle system is a scanning electron microscope.178. A charged particle system, comprising: one or more processors configured to execute instructions to cause the charged particle beam system to perform operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; calculating a difference between the first characteristic of the first component and a target value; calculating a second characteristic to compensate for the difference between the first characteristic of the first component and the target value; and applying the second characteristic to the first component.179. The charged particle system of clause 178, wherein the first characteristic of the first component is a value of an electrical signal.180. The charged particle system of clause 179, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.181. The charged particle system of any one of clauses 178 to 180, wherein the second characteristic is a value of an electrical signal.182. The charged particle system of clause 181, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.183. The charged particle system of any one of clauses 178 to 182, wherein the first component of the charged particle system is a power supply for the charged particle source.184. The charged particle system of clause 183, wherein the power supply is a high voltage supply.185. The charged particle system of any one of clauses 178 to 182, wherein the first component is the charged particle source.186. The charged particle system of clause 185, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.187. The charged particle system of any one of clauses 178 to 186, wherein operations for calculating the second characteristic further comprise: using a controller to convert the difference between the first characteristic of the first component and the target value to the second characteristic.188. The charged particle system of clause 187, wherein the controller is a proportionalintegral derivative (PID) controller, an adaptive control, an automatic disturbance rejection control, a model predictive control, or a robust control.189. The charged particle system of any one of clauses 178 to 188, wherein operations for applying the second characteristic to the first component further comprise: applying the second characteristic to a component of the charged particle source.190. The charged particle system of clause 189, wherein the component of the charged particle source is a cathode, a suppressor, an extractor, or an anode.191. The charged particle system of any one of clauses 178 to 188, wherein operations for applying the second characteristic to the first component further comprise: applying the second characteristic to a component of a power supply of the charged particle source.192. The charged particle system of clause 191, wherein the component of the power supply is communicatively connected to the charged particle source.193. The charged particle system of clause 192, wherein the component of the power supply is communicatively connected to a cathode, a suppressor, an extractor, or an anode of the charged particle source.194. The charged particle system of any one of clauses 178 to 193, wherein operations for applying the second characteristic to the first component compensate for the difference between the first characteristic of the first component and the target value.195. The charged particle system of any one of clauses 178 to 194, wherein a trajectory of the primary beam of charged particles is compensated.196. The charged particle system of any one of clauses 178 to 195, the operations further comprising: collecting an image of a sample of interest.197. The charged particle system of any one of clauses 178 to 196, wherein the charged particle system is an optical microscope.198. The charged particle system of any one of clauses 178 to 196, wherein the charged particle system is a scanning electron microscope.199. A non- transitory computer readable medium comprising a set of instructions that is executable by one or more processors of a computing device to cause the computing device to perform operations for compensating for variations in a charged particle beam system, the operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; determining whether the first characteristic of the first component has deviated from a target value by more than a threshold value;in response to a determination that the first characteristic of the first component has deviated from the target value by more than the threshold value, calculating a second characteristic to compensate for the first characteristic of the first component; and applying the second characteristic to the first component.200. The non-transitory computer readable medium of clause 199, wherein the first characteristic of the first component is a value of an electrical signal.201. The non-transitory computer readable medium of clause 200, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.202. The non-transitory computer readable medium of any one of clauses 199 to 201, wherein the second characteristic is a value of an electrical signal.203. The non-transitory computer readable medium of claim 202, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.204. The non-transitory computer readable medium of any one of clauses 199 to 203, wherein the first component of the charged particle system is a power supply for the charged particle source.205. The non-transitory computer readable medium of clause 204, wherein the power supply is a high voltage supply.206. The non-transitory computer readable medium of any one of clauses 199 to 203, wherein the first component is the charged particle source.207. The non-transitory computer readable medium of clause 206, wherein the first characteristic of the first component is a value of an emission current of the primary beam of charged particles.208. The non-transitory computer readable medium of any one of clauses 199 to 207, wherein operations for calculating the second characteristic further comprise: using a controller to convert the first characteristic to the second characteristic, wherein converting the first characteristic to the second characteristic targets a zero or essentially zero deviation from the target value.209. The non-transitory computer readable medium of clause 208, wherein the controller is a proportional-integral derivative (PID) controller, an adaptive control, an automatic disturbance rejection control, a model predictive control, or a robust control.210. The non-transitory computer readable medium of any one of clauses 199 to 209, wherein applying the second characteristic to the first component further comprises: applying the second characteristic to a component of the charged particle source.211. The non-transitory computer readable medium of clause 210, wherein the component of the charged particle source is a cathode, a suppressor, an extractor, or an anode.212. The non-transitory computer readable medium of any one of clauses 199 to 209, wherein operations for applying the second characteristic to the first component further comprise:applying the second characteristic to a component of a power supply of the charged particle source.213. The non-transitory computer readable medium of clause 212, wherein the component of the power supply is communicatively connected to the charged particle source.214. The non-transitory computer readable medium of clause 213, wherein the component of the power supply is communicatively connected to a cathode, a suppressor, an extractor, or an anode of the charged particle source.215. The non-transitory computer readable medium of any one of clauses 199 to 214, wherein operations for applying the second characteristic to the first component compensate for the first characteristic.216. The non-transitory computer readable medium of any one of clauses 199 to 215, wherein a trajectory of the primary beam of charged particles is compensated.217. The non-transitory computer readable medium of any one of clauses 199 to 216, wherein the operations further comprise: collecting an image of a sample of interest.218. The non-transitory computer readable medium of any one of clauses 199 to 217, wherein the charged particle system is an optical microscope.219. The non-transitory computer readable medium of any one of clauses 199 to 217, wherein the charged particle system is a scanning electron microscope.220. A non-transitory computer readable medium comprising a set of instructions that is executable by one or more processors of a computing device to cause the computing device to perform operations for compensating for variations in a charged particle beam system, the operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a first characteristic of a first component of the charged particle system, wherein the first characteristic of the first component affects an energy level of the primary beam of charged particles; calculating a difference between the first characteristic of the first component and a target value; calculating a second characteristic to compensate for the difference between the first characteristic of the first component and the target value; and applying the second characteristic to the first component.221. The non-transitory computer readable medium of clause 220, wherein the first characteristic of the first component is a value of an electrical signal.222. The non-transitory computer readable medium of clause 221, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.223. The non-transitory computer readable medium of any one of clauses 220 to 222, wherein the second characteristic is a value of an electrical signal.224. The non-transitory computer readable medium of clause 223, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.225. The non-transitory computer readable medium of any one of clauses 220 to 224, wherein the first component of the charged particle system is a power supply for the charged particle source.226. The non-transitory computer readable medium of clause 225, wherein the power supply is a high voltage supply.227. The non-transitory computer readable medium of any one of clauses 220 to 224, wherein the first component is the charged particle source.228. The non-transitory computer readable medium of clause 227, wherein the first characteristic is a value of an emission current of the primary beam of charged particles.229. The non-transitory computer readable medium of any one of clauses 220 to 228, wherein the operations for calculating the second characteristic further comprise: using a controller to convert the difference between the first characteristic of the first component and the target value to the second characteristic.230. The non-transitory computer readable medium of clause 229, wherein the controller is a proportional-integral derivative (PID) controller, an adaptive control, an automatic disturbance rejection control, a model predictive control, or a robust control.231. The non-transitory computer readable medium of any one of clauses 220 to 230, wherein the operations for applying the second characteristic to the first component further comprise: applying the second characteristic to a component of the charged particle source.232. The non-transitory computer readable medium of clause 231, wherein the component of the charged particle source is a cathode, a suppressor, an extractor, or an anode.233. The non-transitory computer readable medium of any one of clauses 220 to 230, wherein the operations for applying the second characteristic to the first component further comprise: applying the second characteristic to a component of a power supply of the charged particle source.234. The non-transitory computer readable medium of clause 233, wherein the component of the power supply is communicatively connected to the charged particle source.235. The non-transitory computer readable medium of clause 234, wherein the component of the power supply is communicatively connected to a cathode, a suppressor, an extractor, or an anode of the charged particle source.236. The non-transitory computer readable medium of any one of clauses 220 to 235, wherein the operations for applying the second characteristic to the first component compensate for the difference between the first characteristic of the first component and the target value.237. The non-transitory computer readable medium of any one of clauses 220 to 236, wherein a trajectory of the primary beam of charged particles is compensated.238. The non-transitory computer readable medium of any one of clauses 220 to 237, the operations further comprising: collecting an image of a sample of interest.239. The non-transitory computer readable medium of any one of clauses 220 to 238, wherein the charged particle system is an optical microscope.240. The non-transitory computer readable medium of any one of clauses 220 to 238, wherein the charged particle system is a scanning electron microscope.241. A method of compensating for variations in a charged particle beam system, comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a characteristic of the charged particle source; and regulating a characteristic of a first component of the charged particle system based on the characteristic of the charged particle source, wherein the characteristic of the first component affects the characteristic of the charged particle source.242. The method of clause 241, wherein regulating the characteristic of the first component comprises reducing a fluctuation of the characteristic of the charged particle source.243. The method of clause 241 or 242, wherein the characteristic of the charged particle source is a value of an emission current of the primary beam of charged particles.244. The method of any one of clauses 241 to 243, wherein regulating a characteristic of the first component of the charged particle system comprises: reducing an output characteristic of the first component of the charged particle system.245. The method of clause 244, wherein the first component of the charged particle system is a power supply for the charged particle source.246. The method of clause 245, wherein the power supply is a high voltage supply.247. The method of any one of clauses 244 to 246, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.248. The method of clause 247, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.249. The method of any one of clauses 244 to 248, wherein the output characteristic of the first component of the charged particle system is a value of an output resistance.250. The method of clause 249, further comprising using a series voltage divider to reduce the value of the output resistance of the first component of the charged particle system.251. The method of any one of clauses 241 to 243, wherein regulating a characteristic of the first component of the charged particle system comprises:increasing a second characteristic of the first component, wherein the first component comprises a control loop.252. The method of clause 251, wherein the first component of the charged particle system is a power supply for the charged particle source.253. The method of clause 252, wherein the power supply is a high voltage supply.254. The method of any one of clauses 251 to 253, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.255. The method of clause 254, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.256. The method of any one of clauses 251 to 255, wherein the second characteristic is a bandwidth range.257. The method of any one of clauses 251 to 256, wherein the control loop comprises a high frequency transformer.258. The method of clause 257, wherein the control loop comprises a switching transformer.259. The method of any one of clauses 251 to 258, wherein the control loop comprises a feedback element with an increased sampling rate.260. The method of any one of clauses 251 to 259, wherein the control loop comprises a digital controller.261. The method of any one of clauses 241 to 243, wherein regulating a characteristic of the first component of the charged particle system comprises: using capacitor matrix to reduce a fluctuation of the characteristic of the first component of the charged particle system.262. The method of clause 261, wherein the capacitor matrix can withstand a high voltage.263. The method of clause 2 1 or 262, wherein the capacitor matrix comprises a combination of series and parallel capacitors.264. The method of any one of clauses 261 to 263, wherein the first component of the charged particle system is a power supply for the charged particle source.265. The method of clause 264, wherein the power supply is a high voltage supply.266. The method of any one of clauses 261 to 265, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.267. The method of any one of clauses 241 to 266, wherein regulating the characteristic of the first component affects a trajectory of the primary beam of charged particles.268. The method of any one of clauses 241 to 267, further comprising: collecting an image of a sample of interest.269. The method of any one of clauses 241 to 268, wherein the charged particle system is an optical microscope.270. The method of any one of clauses 241 to 268, wherein the charged particle system is a scanning electron microscope.271. A charged particle system, comprising: one or more processors configured to execute instructions to cause the system to perform operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a characteristic of the charged particle source; and regulating a characteristic of a first component of the charged particle system based on the characteristic of the charged particle source, wherein the characteristic of the first component affects the characteristic of the charged particle source.272. The charged particle system of clause 271, wherein regulating a characteristic of the first component comprises reducing a fluctuation of the characteristic of the charged particle source.273. The charged particle system of clause 271 or 272, wherein the characteristic of the charged particle source is a value of an emission current of the primary beam of charged particles.274. The charged particle system of any one of clauses 271 to 273, wherein the operations for regulating a characteristic of the first component of the charged particle system comprise: reducing an output characteristic of the first component of the charged particle system.275. The charged particle system of clause 274, wherein the first component of the charged particle system is a power supply for the charged particle source.276. The charged particle system of clause 275, wherein the power supply is a high voltage supply.277. The charged particle system of any one of clauses 274 to 276, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.278. The charged particle system of clause 277, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.279. The charged particle system of any one of clauses 274 to 278, wherein the output characteristic of the first component of the charged particle system is a value of an output resistance.280. The charged particle system of clause 279, further comprising using a series voltage divider to reduce the value of the output resistance of the first component of the charged particle system.281. The charged particle system of any one of clauses 271 to 273, wherein the operations for regulating a characteristic of the first component of the charged particle system comprise: increasing a second characteristic of the first component, wherein the first component comprises a control loop.282. The charged particle system of clause 281, wherein the first component of the charged particle system is a power supply for the charged particle source.283. The charged particle system of clause 282, wherein the power supply is a high voltage supply.284. The charged particle system of any one of clauses 281 to 283, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.285. The charged particle system of clause 284, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.286. The charged particle system of any one of clauses 281 to 285, wherein the second characteristic is a bandwidth range.287. The charged particle system of any one of clauses 281 to 286, wherein the control loop comprises a high frequency transformer.288. The charged particle system of clause 287, wherein the control loop comprises a switching transformer.289. The charged particle system of any one of clauses 281 to 288, wherein the control loop comprises a feedback element with an increased sampling rate.290. The charged particle system of any one of clauses 281 to 289, wherein the control loop comprises a digital controller.291. The charged particle system of any one of clauses 271 to 273, wherein operations for regulating a characteristic of the first component of the charged particle system comprise: using capacitor matrix to reduce a fluctuation of the characteristic of the first component of the charged particle system.292. The charged particle system of clause 291, wherein the capacitor matrix can withstand a high voltage.293. The charged particle system of clause 291 or 292, wherein the capacitor matrix comprises a combination of series and parallel capacitors.294. The charged particle system of any one of clauses 291 to 293, wherein the first component of the charged particle system is a power supply for the charged particle source.295. The charged particle system of clause 294, wherein the power supply is a high voltage supply.296. The charged particle system of any one of clauses 291 to 295, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.297. The charged particle system of any one of clauses 271 to 293, wherein regulating the characteristic of the first component affects a trajectory of the primary beam of charged particles.298. The charged particle system of any one of clauses 271 to 297, the operations further comprising: collecting an image of a sample of interest.299. The charged particle system of any one of clauses 271 to 298, wherein the charged particle system is an optical microscope.300. A non- transitory computer readable medium comprising a set of instructions that is executable by one or more processors of a computing device to cause the computing device to perform operations for compensating for variations in a charged particle beam system, the operations comprising: causing a charged particle source to emit a primary beam of charged particles in a charged particle system; monitoring a characteristic of the charged particle source; and regulating a characteristic of a first component of the charged particle system based on the characteristic of the charged particle source, wherein the characteristic of the first component affects the characteristic of the charged particle source.301. The non-transitory computer readable medium of clause 300, wherein regulating a characteristic of the first component comprises reducing a fluctuation of the characteristic of the charged particle source.302. The non-transitory computer readable medium of clause 300 or 301, wherein the characteristic of the charged particle source is a value of an emission current of the primary beam of charged particles.303. The non-transitory computer readable medium of any one of clauses 300 to 302, wherein the operations for regulating a characteristic of the first component of the charged particle system comprise: reducing an output characteristic of the first component of the charged particle system.304. The non-transitory computer readable medium of clause 303, wherein the first component of the charged particle system is a power supply for the charged particle source.305. The non-transitory computer readable medium of clause 304, wherein the power supply is a high voltage supply.306. The non-transitory computer readable medium of any one of clauses 303 to 305, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.307. The non-transitory computer readable medium of clause 306, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.308. The non-transitory computer readable medium of any one of clauses 303 to 307, wherein the output characteristic of the first component of the charged particle system is a value of an output resistance.309. The non-transitory computer readable medium of clause 308, further comprising using a series voltage divider to reduce the value of the output resistance of the first component of the charged particle system.310. The non-transitory computer readable medium of any one of clauses 300 to 302, wherein the operations for regulating a characteristic of the first component of the charged particle system comprise: increasing a second characteristic of the first component, wherein the first component comprises a control loop.311. The non-transitory computer readable medium of clause 310, wherein the first component of the charged particle system is a power supply for the charged particle source.312. The non-transitory computer readable medium of clause 311, wherein the power supply is a high voltage supply.313. The non-transitory computer readable medium of any one of clauses 310 to 312, wherein the characteristic of the first component of the charged particle system is a value of an electrical signal.314. The non-transitory computer readable medium of clause 313, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.315. The non-transitory computer readable medium of any one of clauses 310 to 314, wherein the second characteristic is a bandwidth range.316. The non-transitory computer readable medium of any one of clauses 310 to 315, wherein the control loop comprises a high frequency transformer.317. The non-transitory computer readable medium of clause 316, wherein the control loop comprises a switching transformer.318. The non-transitory computer readable medium of any one of clauses 310 to 317, wherein the control loop comprises a feedback element with an increased sampling rate.319. The non-transitory computer readable medium of any one of clauses 310 to 318, wherein the control loop comprises a digital controller.320. The non-transitory computer readable medium of any one of clauses 300 to 302, wherein the operations for regulating a characteristic of the first component of the charged particle system comprise: using a capacitor matrix to reduce a fluctuation of the characteristic of the first component of the charged particle system.321. The non-transitory computer readable medium of clause 320, wherein the capacitor matrix can withstand a high voltage.322. The non-transitory computer readable medium of clause 320 or 321, wherein the capacitor matrix comprises a combination of series and parallel capacitors.323. The non-transitory computer readable medium of any one of clauses 320 to 322, wherein the first component of the charged particle system is a power supply for the charged particle source.324. The non-transitory computer readable medium of clause 323, wherein the power supply is a high voltage supply.325. The non-transitory computer readable medium of any one of clauses 320 to 324, wherein the characteristic of the first component of the charged particle system is an electrical signal.326. The non-transitory computer readable medium of any one of clauses 300 to 325, wherein regulating the characteristic of the first component affects a trajectory of the primary beam of charged particles.327. The non-transitory computer readable medium of any one of clauses 300 to 326, the operations further comprising: collecting an image of a sample of interest.328. The non-transitory computer readable medium of any one of clauses 300 to 327, wherein the charged particle system is an optical microscope.329. The method of any one of clauses 1 to 19 or 115 to 135, wherein the threshold value is at least 0.003% of the target value.330. The charged particle system of any one of clauses 39 to 57 or 157 to 177, wherein the threshold value is at least 0.003% of the target value.331. The non-transitory computer readable medium of any one of clauses 77 to 95 or 200 to 219, wherein the threshold value is at least 0.003% of the target value.332. The method of any one of clauses 1 to 114, wherein the second characteristic is a selected voltage, and the second component is a power supply.333. The method of any one of clauses 1 to 114 or 332, wherein applying the second characteristic to the second component includes causing the power supply to output the selected voltage.334. A charged particle system, comprising: a charged particle source configured to emit a primary beam of charged particles, wherein the primary beam of charged particles has a first characteristic; and a first component of the charged particle system configured to affect the first characteristic of the primary beam of charged particles.335. The charged particle system of clause 334, wherein the first characteristic of the primary beam of charged particles comprises an energy level fluctuation of the primary beam of charged particles.336. The charged particle system of clause 334 or 335, wherein the first characteristic of the primary beam of charged particles is a value of an emission current of the primary beam of charged particles.337. The charged particle system of any one of claims 334 to 336, wherein the first component of the charged particle system is configured to reduce a fluctuation of the first characteristic of the primary beam of charged particles.338. The charged particle beam system of any one of clauses 334 to 337, wherein the first component of the charged particle system is a component of the charged particle source.339. The charged particle beam system of clause 338 wherein the first component of the charged particle system comprises an extractor.340. The charged particle system of clause 339, wherein the first component comprises an extractor containing a reduced dimension.341. The charged particle system of any one of clauses 338 to 340, wherein the extractor is configured to reduce a number of charged particles in the primary charged particle beam to pass through the extractor.342. The charged particle system of any one of clauses 334 to 337, wherein the first component comprises a power supply configured to provide a signal to the charged particle source to cause the charged particle source to emit the primary beam of charged particles.343. The charged particle system of clause 342, wherein the power supply is a high voltage supply.344. The charged particle system of clause 342 or 343, wherein the first component of the charged particle system comprises an output characteristic that affects the signal provided to the charged particle source.345. The charged particle system of clause 344, wherein the output characteristic of the first component of the charged particle system is a value of an electrical signal.346. The charged particle system of clause 345, wherein the value of the electrical signal represents a voltage or a current of the electrical signal.347. The charged particle system of any one of clauses 344 to 346, wherein the output characteristic of the first component of the charged particle system is a value of an output resistance.348. The charged particle system of clause 347, wherein the first component of the charged particle system comprises a series voltage divider to reduce the value of the output resistance of the first component of the charged particle system.349. The charged particle system of any one of clauses 344 to 348, wherein the first component of the charged particle system comprises a control loop configured to reduce a fluctuation of the output characteristic of the first component of the charged particle system.350. The charged particle system of clause 349, wherein the control loop is configured to increase a bandwidth range of the first component of the charged particle system.351. The charged particle system of clause 349 or 350, wherein the control loop comprises a high frequency transformer.352. The charged particle system of clause 351, wherein the control loop comprises a switching transformer.353. The charged particle system of any one of clauses 349 to 352, wherein the control loop comprises a feedback element with an increased sampling rate.354. The charged particle system of any one of clauses 349 to 353, wherein the control loop comprises a digital controller.355. The charged particle system of any one of clauses 344 to 354, wherein the first component of the charged particle system comprises a capacitor matrix configured to reduce a fluctuation of the output characteristic of the first component of the charged particle system.356. The charged particle system of clause 355, wherein the capacitor matrix can withstand a high voltage.357. The charged particle system of clause 355 or 356, wherein the capacitor matrix comprises a combination of series and parallel capacitors.358. The charged particle system of any one of clauses 344 to 357, wherein the first component of the charged particle system comprises an output stabilizer comprising circuitry configured to reduce a fluctuation of the output characteristic.359. The charged particle system of clause 358, wherein the output stabilizer is a circuit comprising: a low pass filter (LPF) communicatively coupled to an input supply that provides an electrical signal: and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply wherein the input supply is a voltage source or a current source, wherein the LPF is configured to filter the electrical signal, wherein the PSRR circuit is configured to amplify the filtered electrical signal, and wherein the isolated power supply comprises a ground node that is connected to the input supply.360. The charged particle system of clause 359, wherein the LPF is configured to reduce a fluctuation in the electrical signal.361. The charged particle system of clause 359 or 360, wherein the PSRR circuit comprises an amplifier.361. The charged particle system of any one of clauses 359 to 361, wherein the isolated power supply comprises circuitry configured to provide a positive bias signal and a negative bias signal to the PSRR circuit.362. The charged particle system of clause 361, wherein the positive bias signal comprises a high voltage signal + 5 and the negative bias signal comprises the high voltage signal - 5 bias, wherein the high voltage signal comprises a kV voltage signal and the 5 bias comprises a V voltage bias.363. The charged particle system of any one of clauses 358 to 362, wherein the output stabilizer provides a more stable voltage source to a charged particle source.364. The charged particle system of any one of clauses 358 to 3763, further comprising a protect communicatively coupled to the PSRR circuit.365. The charged particle system of any one of clauses 334 to 364, wherein the first component of the charged particle system affects a trajectory of the primary beam of charged particles.366. The charged particle system of clause 365, wherein the first component of the charged particle beam system stabilizes a trajectory of the primary beam of charged particles.367. The charged particle system of any one of clauses 334 to 366, wherein the charged particle system is a scanning electron microscope.368. A circuit configured to reduce a characteristic in a power supply for a charged particle system, the circuit comprising: a low pass filter (LPF) communicatively coupled to an input supply and configured to filter an electrical signal provided by the input supply, wherein the input supply is a voltage source or a current source; and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the input supply.369. The circuit of clause 368, wherein the input supply is a high voltage supply.370. The circuit of clause 368 or 369, wherein the input supply is a high voltage source.371. The circuit of any one of clauses 368 to 370, wherein the characteristic is a fluctuation in the electrical signal from the input supply.372. The circuit of any one of clauses 368 to 371, wherein the electrical signal is a voltage signal.373. The circuit of clause 372, wherein the electrical signal is a 30 kV signal.374. The circuit of any one of clauses 368 to 373, wherein the LPF is configured to reduce a fluctuation in the electrical signal.375. The circuit of any one of clauses 368 to 374, wherein the PSRR circuit comprises an amplifier.376. The circuit of any one of clauses 368 to 375, wherein the isolated power supply comprises circuitry configured to provide a positive bias signal and a negative bias signal to the PSRR circuit.377. The circuit of clause 376, wherein the positive bias signal comprises a high voltage signal + 3 bias and the negative bias signal comprises the high voltage signal - 6 bias, wherein the high voltage signal comprises a kV voltage and the 3 bias comprises a V voltage bias.378. The circuit of any one of clauses 368 to 377, wherein the isolated power supply is communicatively coupled to a low voltage power source.379. The circuit of clause 378, wherein the low voltage power source is a 24 VDC power source.380. The circuit of any one of clauses 368 to 379, wherein the circuit is located within the power supply.381. The circuit of any one of clauses 368 to 379, wherein the circuit is located outside of the power supply.382. The circuit of clause 381, wherein the circuit is located between the power supply and a charged particle source of the charged particle system.383. The circuit of any one of clause 368 to 382, further comprising a protect communicatively coupled to the PSRR circuit.384. The circuit of any one of clauses 368 to 383, wherein the circuit outputs a more stable voltage source to a component of the charged particle system that affects a trajectory of an emitted primary beam of charged particles.385. The circuit of clause 384, wherein the component of the charged particle system stabilizes the trajectory of the emitted primary beam of charged particles.386. The circuit of clause 384 or 285, wherein the component comprises a charged particle source, a sample stage, or a lens.387. The circuit of any one of clauses 368 to 386, wherein the charged particle system is a scanning electron microscope.388. A charged particle system, comprising: a charged particle source configured to emit a primary beam of charged particles, wherein the primary beam of charged particles has a first characteristic; and a power supply configured to provide an electrical signal to the charged particle source to cause the charged particle source to emit the primary beam of charged particles, wherein the power supply is a voltage source or a current source; and a circuit configured to reduce a characteristic in the electrical signal provided to the charged particle source by the power supply, wherein the circuit comprises: a low pass filter (LPF) communicatively coupled to the power supply and configured to filter the electrical signal provided by the power supply; and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the power supply.389. The charged particle system of clause 388, wherein the power supply is a high voltage source.390. The charged particle system of clause 388 or 389, wherein the characteristic is a fluctuation in the electrical signal from the power supply.391. The circuit of any one of clauses 388 to 390, wherein the electrical signal is a voltage signal.392. The charged particle system of clause 391, wherein the electrical signal is a 30 kV signal.393. The charged particle system of any one of clauses 388 to 392, wherein the LPF is configured to reduce a fluctuation in the electrical signal.394. The charged particle system of any one of clauses 388 to 393, wherein the PSRR circuit comprises an amplifier.395. The charged particle system of any one of clauses 388 to 394, wherein the isolated power supply comprises circuitry configured to provide a positive bias signal and a negative bias signal to the PSRR circuit.396. The charged particle system of clause 395, wherein the positive bias signal comprises a high voltage signal + 5 bias and the negative bias signal comprises the high voltage signal - 6 bias, wherein the high voltage signal comprises a kV voltage and the 5 bias comprises a V voltage bias.397. The charged particle system of any one of clauses 388 to 396, wherein the isolated power supply is communicatively coupled to a low voltage power source.398. The charged particle system of clause 397, wherein the low voltage power source is a 24 VDC power source.399. The charged particle system of any one of clauses 388 to 398, wherein the circuit is located within the power supply.400. The charged particle system of any one of clauses 388 to 398, wherein the circuit is located outside of the power supply.401. The charged particle system of clause 400, wherein the circuit is located between the power supply and the charged particle source.402. The charged particle system of any one of clause 388 to 401, wherein the circuit further comprises a protect communicatively coupled to the PSRR circuit.403. The charged particle system of any one of clauses 388 to 402, wherein the circuit outputs a more stable voltage source to a component of the charged particle system that affects a trajectory of an emitted primary beam of charged particles.404. The charged particle system of clause 403, wherein the component of the charged particle system stabilizes the trajectory of the emitted primary beam of charged particles.405. The charged particle system of clause 403 or 404, wherein the component comprises the charged particle source, a sample stage, or a lens.406. The charged particle system of any one of clauses 388 to 405, wherein the charged particle system is a scanning electron microscope.407. A power supply for a charged particle beam system, the power supply configured to provide an electrical signal to a charged particle source, wherein the electrical signal causes the charged particle source to emit a primary beam of charged particles, wherein the power supplycomprises circuitry configured to reduce a characteristic in the electrical signal provided to the charged particle source by the power supply, and wherein the circuitry comprises: a low pass filter (LPF) communicatively coupled to the power supply and configured to filter the electrical signal provided by the power supply; and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the power supply.408. The power supply of clause 407, wherein the power supply is a high voltage source.409. The power supply of clause 407 or 408, wherein the characteristic is a fluctuation in the electrical signal from the power supply.410. The power supply of any one of clauses 407 to 409, wherein the electrical signal is a voltage signal.411. The power supply of clause 410, wherein the electrical signal is a 30 kV signal.412. The power supply of any one of clauses 407 to 411, wherein the LPF is configured to reduce a fluctuation in the electrical signal.413. The power supply of any one of clauses 407 to 412, wherein the PSRR circuit comprises an amplifier.414. The power supply of any one of clauses 407 to 413, wherein the isolated power supply comprises circuitry configured to provide a positive bias signal and a negative bias signal to the PSRR circuit.415. The power supply of clause 414, wherein the positive bias signal comprises a high voltage signal + 5 bias and the negative bias signal comprises the high voltage signal - 5 bias, wherein the high voltage signal comprises a kV voltage and the 6 bias comprises a V voltage bias.416. The power supply of any one of clauses 407 to 415, wherein the isolated power supply is communicatively coupled to a low voltage power source.417. The power supply of clause 416, wherein the low voltage power source is a 24 VDC power source.418. The power supply of any one of clause 407 to 417, wherein the circuitry further comprises a protect communicatively coupled to the PSRR circuit.419. The power supply of any one of clauses 407 to 418, wherein the circuitry outputs a more stable voltage source to a component of the charged particle system that affects a trajectory of an emitted primary beam of charged particles.420. The power supply of clause 419, wherein the component of the charged particle system stabilizes the trajectory of the emitted primary beam of charged particles.421. The power supply of clause 419 or 420, wherein the component comprises the charged particle source, a sample stage, or a lens.422. The power supply of any one of clauses 407 to 421, wherein the charged particle system is a scanning electron microscope.423. The method of any one of clauses 1 to 19 or 115 to 135, wherein the threshold value is zero or essentially zero. 424. The charged particle system of any one of clauses 39 to 57 or 157 to 177, wherein the threshold value is zero or essentially zero.425. The non-transitory computer readable medium of any one of clauses 77 to 95 or 200 to 219, wherein the threshold value is zero or essentially zero.

[0129] It will be appreciated that the embodiments of the present disclosure are not limited to the exact construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof. The present disclosure has been described in connection with various embodiments, other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

CLAIMS1. A circuit configured to reduce a characteristic in a power supply for a charged particle system, the circuit comprising: a low pass filter (LPF) communicatively coupled to an input supply and configured to filter an electrical signal provided by the input supply, wherein the input supply is a voltage source or a current source; and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the input supply.

2. The circuit of claim 1, wherein the input supply is a high voltage supply.

3. The circuit of claim 1, wherein the characteristic is a fluctuation in the electrical signal from the input supply.

4. The circuit of claim 1, wherein the electrical signal is a voltage signal.

5. The circuit of claim 1, wherein the LPF is configured to reduce a fluctuation in the electrical signal.

6. The circuit of claim 1, wherein the PSRR circuit comprises an amplifier.

7. The circuit of claim 1, wherein the isolated power supply comprises circuitry configured to provide a positive bias signal and a negative bias signal to the PSRR circuit.

8. The circuit of claim 7, wherein the positive bias signal comprises a high voltage signal + 5 bias and the negative bias signal comprises the high voltage signal - 5 bias, wherein the high voltage signal comprises a kV voltage and the 5 bias comprises a V voltage bias.

9. The circuit of claim 1, wherein the isolated power supply is communicatively coupled to a low voltage power source.

10. The circuit of claim 1, further comprising a protect communicatively coupled to the PSRR circuit.

11. The circuit of claim 1, wherein the circuit outputs a more stable voltage source to a component of the charged particle system that affects a trajectory of an emitted primary beam of charged particles.

12. The circuit of claim 11, wherein the component of the charged particle system stabilizes the trajectory of the emitted primary beam of charged particles.

13. The circuit of claim 11, wherein the component comprises a charged particle source, a sample stage, or a lens.

14. A charged particle system, comprising: a charged particle source configured to emit a primary beam of charged particles, wherein the primary beam of charged particles has a first characteristic; and a power supply configured to provide an electrical signal to the charged particle source to cause the charged particle source to emit the primary beam of charged particles, wherein the power supply is a voltage source or a current source; and a circuit configured to reduce a characteristic in the electrical signal provided to the charged particle source by the power supply, wherein the circuit comprises: a low pass filter (LPF) communicatively coupled to the power supply and configured to filter the electrical signal provided by the power supply; and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the power supply.

15. A power supply for a charged particle beam system, the power supply configured to provide an electrical signal to a charged particle source, wherein the electrical signal causes the charged particle source to emit a primary beam of charged particles, wherein the power supply is comprises circuitry configured to reduce a characteristic in the electrical signal provided to the charged particle source by the power supply, and wherein the circuitry comprises: a low pass filter (LPF) communicatively coupled to the power supply and configured to filter the electrical signal provided by the power supply; and a power supply rejection ratio (PSRR) circuit communicatively coupled to the low pass filter and powered by an isolated power supply, wherein the PSRR circuit is configured to amplify the filtered electrical signal and the isolated power supply comprises a grounding node that is communicatively coupled to the power supply.

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