Advanced charge controller configurations for charged particle systems.

Abstract

A system, apparatus, and method for advanced charge controller configuration in a charged particle system may include a light source configured to emit a light beam and a mirror system configured to adjust the angle of incidence of the light beam on a sample during inspection of the sample without substantially adjusting the position of the light beam on the sample.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application Publication No. 63 / 434,037, filed December 20, 2022, the entire contents of which are incorporated herein by reference.

[0002] TECHNICAL FIELD

[0002] The description herein relates to the field of charged particle systems, and more particularly to advanced charge controller configurations in charged particle systems. [Background technology]

[0003]

[0003] In the integrated circuit (IC) manufacturing process, unfinished or completed circuit components are inspected to ensure they are manufactured according to design and are free of defects. Inspection systems that utilize optical microscopes typically have a resolution of up to a few hundred nanometers, with resolution limited by the wavelength of light. As the physical size of IC components continues to shrink to sub-100 nanometers or even sub-10 nanometers, inspection systems with higher resolution than those that utilize optical microscopes are needed.

[0004]

[0004] Charged particle (e.g., electron) beam microscopes with resolution down to less than 1 nanometer, such as scanning electron microscopes (SEMs) or transmission electron microscopes (TEMs), serve as practical tools for inspecting IC components with feature sizes of sub-100 nanometers. When using an SEM, electrons from a single primary electron beam, or multiple primary electron beams, may be focused onto a wafer at a location of interest during inspection. The primary electrons interact with the wafer and may be backscattered or may cause the wafer to emit secondary electrons. The intensity of the electron beam, including the backscattered and secondary electrons, may vary based on the characteristics of the wafer's internal and external structure, which may indicate whether the wafer is defective. Summary of the Invention

[0005]

[0005] Embodiments of the present disclosure provide apparatus, systems, and methods for advanced charge controller configurations in charged particle systems. In some embodiments, the systems and methods may include a light source configured to emit a light beam and a mirror system configured to adjust the angle of incidence of the light beam on a sample during inspection of the sample without substantially adjusting the position of the light beam on the sample.

[0006]

[0006] In some embodiments, the system may include a module configured to emit a beam that illuminates an area on the sample and a mirror system configured to adjust the angle of the beam that illuminates the sample without substantially adjusting the position of the beam on the sample.

[0007]

[0007] In some embodiments, the system may include a module configured to emit a beam that illuminates an area on the sample, and a mirror system including a first mirror having an adjustable position for adjusting the angle of the beam that illuminates the sample without substantially adjusting the position of the beam's illumination on the sample. [Brief explanation of the drawings]

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

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

[0010] 2 is a schematic diagram illustrating an example single beam system that is part of the example charged particle beam inspection system of FIG. 1, consistent with an embodiment of the present disclosure. [Figure 3]

[0011] FIG. 1 is a schematic diagram illustrating an exemplary electron beam system consistent with an embodiment of the present disclosure. [Figure 4]

[0012] 1 is an exemplary graph illustrating secondary electron yield rate versus landing energy of primary electron beamlets, consistent with embodiments of the present disclosure. [Figure 5]

[0013] FIG. 1 is a schematic diagram illustrating an exemplary voltage contrast response of a wafer, consistent with an embodiment of the present disclosure. [Figure 6]

[0014] 1 is a schematic diagram of an exemplary charged particle system consistent with embodiments of the present disclosure. [Figure 7]

[0015] 1 shows a graph, consistent with an embodiment of the present disclosure. [Figure 8]

[0016] 1 is a flowchart illustrating an exemplary process consistent with embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009]

[0017] 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, unless otherwise stated, like numbers in different drawings represent the same or similar elements. The implementations described in the following description of exemplary embodiments do not represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with aspects of the subject matter 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 may be applied as well. Furthermore, other imaging systems, such as optical imaging, light detection, x-ray detection, extreme ultraviolet inspection, deep ultraviolet inspection, etc., may be used, which generate corresponding types of images.

[0010]

[0018] Electronic devices are built with circuits formed on a piece of silicon called a substrate. Many circuits may be formed together on the same piece of silicon, called an integrated circuit, or IC. The size of these circuits has decreased dramatically, allowing more circuits to fit on a substrate. For example, an IC chip in a smartphone can be about the size of a thumbnail yet contain over 2 billion transistors, each less than 1 / 1000 the thickness of a human hair.

[0011]

[0019] Fabricating these extremely small ICs is a complex, time-consuming, and expensive process, often involving hundreds of individual steps. An error in just one step can result in a defect in the finished IC, rendering it useless. Therefore, one of the goals of a manufacturing process is to avoid such defects and maximize the number of functional ICs produced in the process, thereby improving the overall yield of the process.

[0012]

[0020] One factor in improving yield is monitoring the chip fabrication process to ensure it produces a sufficient number of functional ICs. One technique for monitoring the process is to inspect the chip circuit structures at various stages in their formation. Inspection can be performed using a scanning electron microscope (SEM). An SEM can be used to image these extremely small structures, essentially taking a "picture" of the wafer. This image can be used to determine whether the structures were formed properly and whether they were formed in the correct location. If the structures are defective, the process can be adjusted to reduce the likelihood of the defect occurring again. Defects can be created at various stages of semiconductor processing. For the reasons stated above, it is important to find defects as quickly, accurately, and efficiently as possible.

[0013]

[0021] The operating principle of an SEM is similar to that of a camera. A camera takes pictures by receiving and recording the brightness and color of light reflected or emitted from a person or object. An SEM takes "pictures" by receiving and recording the energy or quantity of electrons reflected or emitted from a structure. Before taking such a "picture," an electron beam may be directed onto the structure, and as electrons reflect or emit ("emit") from the structure, the SEM's detector may receive and record the energy or quantity of those electrons to generate an image. Some SEMs use a single electron beam to take such a "picture" (called a "single-beam SEM"), while other SEMs use multiple electron beams to take multiple "pictures" of the wafer (called a "multi-beam SEM"). By using multiple electron beams, the SEM can provide more electron beams onto the structure to obtain these multiple "pictures," resulting in more electrons being emitted from the structure. Thus, the detector can simultaneously receive more emitted electrons, producing images of the wafer's structures with greater efficiency and speed.

[0014]

[0022] When an electron beam is directed at a sample, secondary electrons are emitted in response. An advanced charge control (ACC) module can be used to manipulate or control the sample's response to the electron beam. For example, the ACC module can modulate the emission of secondary electrons by illuminating the sample with a light beam, such as a laser beam, which changes the emission of secondary electrons by the sample.

[0015]

[0023] Multi-wavelength ACC module designs can be used in inspection systems to modulate the emission of secondary electrons by a sample. For example, depending on the material or structure of the sample being inspected, different wavelengths of light from the ACC module can exhibit different modulations of secondary electron emission. A typical ACC module can use MEMS mirrors to direct one or more light beams of a certain size to a point on the sample at a certain angle of incidence. In some cases, the MEMS mirrors can direct the light beams to an area of ​​the sample to be scanned or an area of ​​the sample that will be scanned by an electron beam (e-beam). A typical ACC module can use a dichroic mirror to combine the multi-wavelength light beams to stimulate different nanostructures on different sample surfaces.

[0016]

[0024] The performance of the ACC module can be improved by increasing the optical coupling efficiency between the light beam from the ACC module and the material of the sample being inspected. The optical coupling efficiency can depend on the angle of incidence of the light beam on the sample. Different sample materials can exhibit higher optical coupling efficiency at different angles of incidence.

[0017]

[0025] However, typical ACC module configurations have limitations. In typical ACC module configurations, the range of incident angles between the light beam and the sample is limited. In some cases, the incident angle is fixed in typical ACC module configurations. Although the light coupling efficiency can be increased by changing or coupling the wavelength of the ACC module's light beam, doing so requires tedious hardware modifications (e.g., adding or removing mirrors, adding ACC modules, etc.). Therefore, the light coupling efficiency of typical ACC modules is limited.

[0018]

[0026] The disclosed embodiments provide systems and methods that may address some or all of these shortcomings by providing an ACC module configuration that allows a wider range of incidence angles between the light beam from the ACC module and the sample. The disclosed embodiments may provide a light source configured to emit a light beam and a mirror system configured to adjust the angle of incidence of the light beam on the sample during inspection of the sample without substantially adjusting the position of the light beam on the sample.

[0019]

[0027] The relative dimensions of components in the drawings may be exaggerated for clarity. Within the following description of the drawings, the same or similar reference numbers refer to the same or similar components or entities, and only the differences with respect to individual embodiments are described.

[0020]

[0028] As used herein, unless otherwise specified, the term "or" includes all possible combinations unless it is not feasible. For example, if it is specified that a component may include A or B, then the component may include A, or B, or A and B, unless otherwise specified or not feasible. As a second example, if it is specified that a component may include A, B, or C, then the component may include A, or B, or C, or A and B, or A and C, or B and C, or A, B, and C, unless otherwise specified or not feasible.

[0021]

[0029] Without limiting the scope of the present disclosure, some embodiments may be described in connection with providing detectors and detection methods in systems utilizing electron beams. However, the present disclosure is not so limited. Other types of charged particle beams may be applied as well. Furthermore, the detection systems and methods may be used in other imaging systems, such as optical imaging, photon detection, x-ray detection, ion detection, etc.

[0022]

[0030] FIG. 1 illustrates an exemplary electron beam inspection (EBI) system 100 consistent with embodiments of the present disclosure. The EBI system 100 can be used for imaging. As shown in FIG. 1, the EBI system 100 includes a main chamber 101, a load / lock chamber 102, an electron beam tool 104, and an equipment front-end module (EFEM) 106. The electron beam tool 104 is located within the main chamber 101. The EFEM 106 includes a first load port 106a and a second load port 106b. The EFEM 106 may include additional load ports. The first load port 106a and the second load port 106b receive wafers (e.g., semiconductor wafers or wafers made of other materials) or wafer front-opening integrated pods (FOUPs) containing samples to be inspected (wafers and samples may be used interchangeably). A "lot" is a plurality of wafers that can be loaded for processing as a batch.

[0023]

[0031] One or more robot arms (not shown) of the EFEM 106 can transfer the wafer to the load / lock chamber 102. The load / lock chamber 102 is connected to a load / lock vacuum pumping system (not shown) that removes gas molecules from the load / lock chamber 102 to reach a first pressure below atmospheric pressure. After the first pressure is reached, one or more robot arms (not shown) can transfer the wafer from the load / lock chamber 102 to the main chamber 101. The main chamber 101 is connected to a main chamber vacuum pumping system (not shown) that removes gas molecules from the main chamber 101 to reach a second pressure less than the first pressure. After the second pressure is reached, the wafer undergoes inspection by the electron beam tool 104. The electron beam tool 104 can be a single beam system or a multi-beam system.

[0024]

[0032] The controller 109 is electronically connected to the electron beam tool 104. The controller 109 may be a computer configured to perform various controls of the EBI system 100. While the controller 109 is shown in Figure 1 as being external to the structure including the main chamber 101, the load / lock chamber 102, and the EFEM 106, it is understood that the controller 109 may also be part of the structure.

[0025]

[0033] In some embodiments, the controller 109 may include one or more processors (not shown). A processor may be a general-purpose or special-purpose electronic device capable of manipulating or processing information. For example, a processor may include any number or combination of a central processing unit (or "CPU"), a graphics processing unit (or "GPU"), an optical processor, a programmable logic controller, a microcontroller, a microprocessor, a digital signal processor, an intellectual property (IP) core, a programmable logic array (PLA), a programmable array logic (PAL), a 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), and any type of circuit capable of processing data. A processor may also be a virtual processor, including one or more processors distributed across multiple machines or devices coupled via a network.

[0026]

[0034] In some embodiments, the controller 109 may further include one or more memories (not shown). Memory may be a general-purpose or special-purpose electronic device capable of storing code and data accessible by the processor (e.g., via a bus). For example, memory may include any combination of any number of random access memory (RAM), read-only memory (ROM), optical disks, magnetic disks, hard drives, solid-state drives, flash drives, security digital (SD) cards, memory sticks, compact flash (CF) cards, or any type of storage device. Code may include an operating system (OS) and one or more application programs (or "apps") for specific tasks. Memory may also be virtual memory, which includes one or more memories distributed across multiple machines or devices coupled via a network.

[0027]

[0035] Embodiments of the present disclosure may provide a single charged particle beam imaging system ("single beam system"). Compared to a single beam system, a multiple charged particle beam imaging system ("multi-beam system") may be designed to optimize throughput for different scan modes. Embodiments of the present disclosure provide a multi-beam system with the ability to optimize throughput for different scan modes by using beam arrays with different geometries to accommodate different throughput and resolution requirements.

[0028]

[0036] Reference is now made to FIG. 2A , which is a schematic diagram illustrating an exemplary electron beam tool 104 comprising a multi-beam inspection tool that is part of the EBI system 100 of FIG. 1 , consistent with embodiments of the present disclosure. In some embodiments, the electron beam tool 104 may be operated as a single-beam inspection tool that is part of the EBI system 100 of FIG. 1 . The multi-beam electron beam tool 104 (also referred to herein as apparatus 104) includes an electron source 201, a Coulomb aperture plate (or “gun aperture plate”) 271, a condenser lens 210, a source conversion unit 220, a primary projection system 230, a motorized stage 209, and a sample holder 207 supported by the motorized stage 209 for holding a sample 208 (e.g., a wafer or photomask) to be inspected. The multi-beam electron beam tool 104 may further include a secondary projection system 250 and an electron detection device 240. The primary projection system 230 may include an objective lens 231. The electronic detection device 240 may include a plurality of detection elements 241, 242, and 243. The beam separator 233 and the deflection scanning unit 232 may be positioned inside the primary projection system 230.

[0029]

[0037] The electron source 201, the Coulomb aperture plate 271, the condenser lens 210, the radiation source conversion unit 220, the beam separator 233, the deflection scanning unit 232, and the primary projection system 230 may be aligned with a primary optical axis 204 of the apparatus 104. The secondary projection system 250 and the electron detection device 240 may be aligned with a secondary optical axis 251 of the apparatus 104.

[0030]

[0038] The electron source 201 may include a cathode (not shown) and an extractor or anode (not shown), and during operation, the electron source 201 is configured to emit primary electrons from the cathode, which are extracted or accelerated by the extractor and / or anode to form a primary electron beam 202 that forms a primary beam crossover (virtual or real) 203. The primary electron beam 202 may be visualized as being emitted from the primary beam crossover 203.

[0031]

[0039] The source conversion unit 220 may include an image-forming element array (not shown), an aberration compensator array (not shown), a beam-limiting aperture array (not shown), and a pre-bending micro-deflector array (not shown). In some embodiments, the pre-bending micro-deflector array deflects multiple primary beamlets 211, 212, 213 of the primary electron beam 202 to be perpendicularly incident on the beam-limiting aperture array, the image-forming element array, and the aberration compensator array. In some embodiments, the apparatus 104 may be operated as a single beam system such that a single primary beamlet is generated. In some embodiments, the condenser lens 210 is designed to focus the primary electron beam 202 to be a parallel beam perpendicularly incident on the source conversion unit 220. The imaging element array may include a plurality of micro-deflectors or micro-lenses, one for each of the primary beamlets 211, 212, 213, for influencing the plurality of primary beamlets 211, 212, 213 of the primary electron beam 202 and for forming a plurality of parallel images (virtual or real images) of the primary beam crossover 203. In some embodiments, the aberration compensator array may include a field curvature compensator array (not shown) and an astigmatism compensator array (not shown). The field curvature compensator array may include a plurality of micro-lenses for compensating for field curvature aberration of the primary beamlets 211, 212, and 213. The astigmatism compensator array may include a plurality of micro-astigmatism correctors for compensating for astigmatism of the primary beamlets 211, 212, and 213. The beam-limiting aperture array may be configured to limit the diameter of each of the primary beamlets 211, 212, and 213. 2A shows three primary beamlets 211, 212, and 213 as an example, it being understood that the source conversion unit 220 may be configured to form any number of primary beamlets. The controller 109 may be connected to various parts of the EBI system 100 of FIG. 1, such as the source conversion unit 220, the electron detection device 240, the primary projection system 230, or the motorized stage 209. In some embodiments, the controller 109 may perform various image and signal processing functions, as described in more detail below.The controller 109 may also generate various control signals to control the operation of the charged particle beam inspection system.

[0032]

[0040] The condenser lens 210 is configured to focus the primary electron beam 202. The condenser lens 210 may be further configured to adjust the current of the primary beamlets 211, 212, and 213 downstream of the radiation source conversion unit 220 by changing the focusing power of the condenser lens 210. Alternatively, the current may be changed by changing the radial size of a beam-limiting aperture in a beam-limiting aperture array corresponding to each primary beamlet. The current may be changed by changing both the radial size of the beam-limiting aperture and the focusing power of the condenser lens 210. The condenser lens 210 may be an adjustable condenser lens configured such that the position of its first principal plane is movable. The adjustable condenser lens may be configured to be magnetic, which may result in the off-axis beamlets 212 and 213 irradiating the radiation source conversion unit 220 with a rotation angle. The rotation angle varies with the focusing power or the position of the first principal plane of the adjustable condenser lens. The collecting lens 210 may be an anti-rotation collecting lens that may be configured to keep the rotation angle constant while changing the focusing power of the collecting lens 210. In some embodiments, the collecting lens 210 may be an adjustable anti-rotation collecting lens that does not change the rotation angle when changing the focusing power and the position of the first principal plane.

[0033]

[0041] The objective lens 231 may be configured to focus the beamlets 211, 212, and 213 onto the sample 208 for inspection, which in this embodiment may form three probe spots 221, 222, and 223 on the surface of the sample 208. The Coulomb aperture plate 271 is configured, in operation, to block peripheral electrons of the primary electron beam 202 to reduce the Coulomb effect, which can increase the size of each of the probe spots 221, 222, and 223 of the primary beamlets 211, 212, 213, and thus degrade the inspection resolution.

[0034]

[0042] The beam separator 233 may be, for example, a Wien filter including electrostatic deflectors that generate electrostatic and magnetic dipole fields (not shown in FIG. 2A ). In operation, the beam separator 233 may be configured to exert an electrostatic force on individual electrons of the primary beamlets 211, 212, and 213 by the electrostatic dipole field. This electrostatic force is equal in magnitude but opposite in direction to the magnetic force exerted on the individual electrons by the magnetic dipole field of the beam separator 233. Therefore, the primary beamlets 211, 212, and 213 may pass at least substantially straight through the beam separator 233 with at least substantially zero deflection angle.

[0035]

[0043] The deflection scanning unit 232 is configured, in operation, to deflect the primary beamlets 211, 212, and 213 to scan the probe spots 221, 222, and 223 over respective scan areas on a section of the surface of the sample 208. In response to the primary beamlets 211, 212, and 213, or the probe spots 221, 222, and 223, being incident on the sample 208, electrons emerge from the sample 208 and generate three secondary electron beams 261, 262, and 263. Each of the secondary electron beams 261, 262, and 263 typically includes secondary electrons (having an electron energy ≦50 eV) and backscattered electrons (having an electron energy between 50 eV and the landing energy of the primary beamlets 211, 212, and 213). Beam separator 233 is configured to deflect secondary electron beams 261, 262, and 263 towards secondary projection system 250. Secondary projection system 250 then focuses secondary electron beams 261, 262, and 263 onto detector elements 241, 242, and 243 of electron detection device 240. Detector elements 241, 242, and 243 are arranged to detect corresponding secondary electron beams 261, 262, and 263 and generate corresponding signals, which are sent to controller 109 or a signal processing system (not shown), for example, to construct an image of a corresponding scan area of ​​sample 208.

[0036]

[0044] In some embodiments, detector elements 241, 242, and 243 detect corresponding secondary electron beams 261, 262, and 263, respectively, and generate corresponding intensity signal outputs (not shown) to an image processing system (e.g., controller 109). In some embodiments, each detector element 241, 242, and 243 may include one or more pixels. The intensity signal output of a detector element may be the sum of signals generated by all of the pixels in the detector element.

[0037]

[0045] In some embodiments, the controller 109 may include an image processing system including an image acquirer (not shown) and storage (not shown). The image acquirer may include one or more processors. For example, the image acquirer may include a computer, a server, a mainframe host, a terminal, a personal computer, any type of mobile computing device, and the like, or a combination thereof. The image acquirer may be communicatively coupled to the electronic detection device 240 of the apparatus 104 through a medium such as electrical conductors, a fiber optic cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, wireless communication, or a combination thereof, among others. In some embodiments, the image acquirer may receive signals from the electronic detection device 240 and construct an image. Thus, the image acquirer may acquire an image of the sample 208. The image acquirer may also perform various post-processing functions, such as generating contours and overlaying indicators on the acquired image. The image acquirer may be configured to perform adjustments, such as brightness and contrast, on the acquired image. In some embodiments, the storage may be a storage medium, such as a hard disk, a flash drive, cloud storage, random access memory (RAM), or other types of computer-readable memory. The storage may be coupled to the image acquirer and may be used to store raw scanned image data as original images and to store processed images.

[0038]

[0046] In some embodiments, the image acquirer may acquire one or more images of the sample based on an imaging signal received from the electronic detection device 240. The imaging signal may correspond to a scanning operation for performing charged particle imaging. The acquired image may be a single image including multiple imaging areas. The single image may be stored in storage. The single image may be an original image that may be divided into multiple regions. Each region may include an imaging area that includes a feature of the sample 208. The acquired image may include multiple images of a single imaging area of ​​the sample 208 sampled multiple times in a time series. The multiple images may be stored in storage. In some embodiments, the controller 109 may be configured to perform image processing steps using multiple images of the same location of the sample 208.

[0039]

[0047] In some embodiments, the controller 109 may include measurement circuitry (e.g., an analog-to-digital converter) to obtain a distribution of detected secondary electrons. The electron distribution data collected during the detection time window in combination with the corresponding scan path data of each primary beamlet 211, 212, and 213 incident on the wafer surface can be used to reconstruct an image of the wafer structure under inspection. The reconstructed image can be used to reveal various features of the internal or external structure of the sample 208, and thereby reveal any defects that may be present in the wafer.

[0040]

[0048] In some embodiments, the controller 109 may control the motorized stage 209 to move the sample 208 during inspection of the sample 208. In some embodiments, the controller 109 may enable the motorized stage 209 to move the sample 208 continuously in one direction at a constant speed. In other embodiments, the controller 109 may enable the motorized stage 209 to vary the speed at which the sample 208 moves over time depending on the step in the scanning process.

[0041]

[0049] 2A shows that the apparatus 104 uses three primary electron beams, it is understood that the apparatus 104 may use one, two, or more primary electron beams. This disclosure does not limit the number of primary electron beams used in the apparatus 104. In some embodiments, the apparatus 104 may be an SEM used for lithography. In some embodiments, the electron beam tool 104 may be a single beam system or a multi-beam system.

[0042]

[0050] For example, as shown in FIG. 2B , electron beam tool 100B (also referred to herein as apparatus 100B) may be a single-beam inspection tool used in EBI system 10 consistent with embodiments of the present disclosure. Apparatus 100B includes a wafer holder 136 supported by a motorized stage 134 for holding a wafer 150 to be inspected. Electron beam tool 100B includes an electron emitter, which may include a cathode 103, an anode 121, and a gun aperture 122. Electron beam tool 100B further includes a beam-limiting aperture 125, a condenser lens 126, a column aperture 135, an objective lens assembly 132, and a detector 144. Objective lens assembly 132 may be a modified SORIL lens in some embodiments and includes a pole piece 132a, a control electrode 132b, a deflector 132c, and an excitation coil 132d. In the imaging process, an electron beam 161 emanating from the tip of the cathode 103 may be accelerated by the anode 121 voltage, pass through the gun aperture 122, the beam-limiting aperture 125, the condenser lens 126, and be focused by a modified SORIL lens to a probe spot 170, which may impinge on the surface of the wafer 150. The probe spot 170 may be scanned across the surface of the wafer 150 by a deflector, such as deflector 132c or other deflectors of a SORIL lens. Secondary particles or scattered primary particles, such as secondary electrons or scattered primary electrons emanating from the wafer surface, may be collected by a detector 144 to determine the intensity of the beam, so that an image of the area of ​​interest on the wafer 150 may be reconstructed.

[0043]

[0051] An image processing system 199 may also be provided, including the image acquirer 120, the storage 130, and the controller 109. The image acquirer 120 may include one or more processors. For example, the image acquirer 120 may include a computer, a server, a mainframe host, a terminal, a personal computer, any type of mobile computing device, etc., or a combination thereof. The image acquirer 120 may be connected to the detector 144 of the electron beam tool 100B through a medium such as electrical conductors, a fiber optic cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, wireless communication, or a combination thereof. The image acquirer 120 may receive signals from the detector 144 and construct an image. Thus, the image acquirer 120 may acquire an image of the wafer 150. The image acquirer 120 may also perform various post-processing functions, such as generating contours and overlaying indicators on the acquired image. The image acquirer 120 may be configured to perform adjustments, such as brightness and contrast, on the acquired image. The storage 130 may be a storage medium such as a hard disk, random access memory (RAM), cloud storage, or other type of computer-readable memory. The storage 130 may be coupled to the image acquirer 120 and may be used to store raw scanned image data as original images and to store processed images. The image acquirer 120 and the storage 130 may be connected to the controller 109. In some embodiments, the image acquirer 120, the storage 130, and the controller 109 may be integrated together as a single electronic control unit.

[0044]

[0052] In some embodiments, the image acquirer 120 may acquire one or more images of the sample based on an imaging signal received from the detector 144. The imaging signal may correspond to a scanning motion to perform charged particle imaging. The acquired image may be a single image including multiple imaging areas that may include various features of the wafer 150. The single image may be stored in the storage 130. The imaging may be performed based on imaging frames.

[0045]

[0053] The collection and illumination optics of an electron beam tool may include or be supplemented by electromagnetic quadrupole electron lenses. For example, as shown in FIG. 2B, electron beam tool 100B may include a first quadrupole lens 148 and a second quadrupole lens 158. In some embodiments, the quadrupole lenses are used to control the electron beam. For example, first quadrupole lens 148 may be controlled to adjust the beam current, and second quadrupole lens 158 may be controlled to adjust the beam spot size and beam shape.

[0046]

[0054] 2B shows a charged particle beam device in which the inspection system may use a single primary beam that may be configured to generate secondary electrons by interacting with the wafer 150. The detector 144 may be positioned along the optical axis 105, as in the embodiment shown in FIG. 2B. The primary electron beam may be configured to travel along the optical axis 105. Thus, the detector 144 may include a hole in the center of the detector 144 to allow the primary electron beam to pass through and reach the wafer 150.

[0047]

[0055]

[0033] Figure 3 illustrates an electron beam system 300 consistent with an embodiment of the present disclosure. As shown in Figure 3, the electron beam system 300 includes an electron beam tool 310 (e.g., electron beam tool 104 of Figure 1, electron beam tool 104 of Figure 2A, electron beam tool 100B of Figure 2B), an ACC module 320 (e.g., ACC module), and a wafer holder 330 (e.g., motorized stage 209 of Figure 2A, motorized stage 134 of Figure 2B) on which a sample to be inspected (e.g., sample 208 of Figure 2A, wafer 150 of Figure 2B, sample 605 of Figure 6) (e.g., wafer 340) is positioned. The electron beam tool 310 may emit a primary electron beam 312 (e.g., multiple beamlets 211, 212, or 213 of the primary electron beam 202 in FIG. 2A , the electron beam 161 in FIG. 2B , or the electron beam 607 in FIG. 6 ) onto a target area on the wafer 340 and collect secondary electrons emitted from the wafer surface to form an image of the target area on the wafer 340. The ACC module 320 may include an ACC beam source that emits a light beam 322 (e.g., a laser beam, the light beam 601 in FIG. 6 ) onto the wafer 340 and form a beam spot 342 (e.g., area 603 in FIG. 6 ) of the light beam 322 on the wafer surface during inspection. The light beam 322 may be emitted onto the wafer 340 at an incident angle θ of the light beam 322. When the primary electron beam 312 irradiates the target area on the wafer 340, charge may accumulate due to a large electron beam current. The light beam 322 emitted from the ACC module 320 can be configured to modulate the charge accumulated by, among other things, photoconduction or photoelectric effect, or a combination of photoconduction and photoelectric effect.

[0048]

[0056] In some embodiments, wafer 340 may include a PN junction diode or bulk semiconductor material. In some embodiments, the ACC beam source may be a light source.

[0049]

[0057] In some embodiments, the electron beam tool 310 may generate multiple primary electron beamlets to simultaneously scan multiple locations on the wafer 340. In some embodiments, the beam projected by the ACC module 320 may charge a location on the wafer 340 that is large enough so that multiple primary electron beamlets can scan corresponding portions on the wafer 340.

[0050]

[0058] FIG. 4 is an exemplary graph showing the yield rate of secondary electrons versus the landing energy of primary electron beamlets, consistent with an embodiment of the present disclosure. The graph illustrates the relationship between the landing energy of multiple beamlets of a primary electron beam (e.g., multiple beamlets 211, 212, or 213 of primary electron beam 202 in FIG. 2A , electron beam 161 in FIG. 2B , primary electron beam 312 in FIG. 3 , or electron beam 607B in FIG. 6 ) and the yield rate of a secondary electron beam (e.g., secondary electron beam 261, 262, or 263 in FIG. 2A ). The yield rate indicates the number of secondary electrons generated in response to the impact of a primary electron. For example, a yield rate greater than 1.0 indicates that more secondary electrons may be generated than the number of primary electrons that land on the wafer. Similarly, a yield rate less than 1.0 indicates that fewer secondary electrons may be generated in response to the impact of a primary electron.

[0051]

[0059] As shown in the graph of FIG. 4, when the landing energy of primary electrons is within the range of E1 to E2, more electrons may leave the wafer surface than land on it, which may result in a positive potential at the wafer surface. In some embodiments, defect inspection may be performed within the aforementioned landing energy range, referred to as a "positive mode." An electron beam tool (e.g., electron beam tool 104 of FIG. 2A or electron beam tool 100B of FIG. 2B) may produce darker voltage-contrast images of device structures with a more positive surface potential because a detection device (e.g., detection device 240 of FIG. 2A or detector 144 of FIG. 2B) may receive fewer secondary electrons (see FIG. 5).

[0052]

[0060] If the landing energy is lower than E1 or higher than E2, fewer electrons will leave the wafer's surface, which may result in a negative potential at the wafer's surface. In some embodiments, defect inspection may be performed within this range of landing energies, referred to as a "negative mode." An electron beam tool (e.g., electron beam tool 104 of FIG. 2A, electron beam tool 100B of FIG. 2B) may produce brighter voltage-contrast images of device structures with more negative surface potentials, where a detection device (e.g., detection device 240 of FIG. 2A, detector 144 of FIG. 2B) may receive more secondary electrons (see FIG. 5).

[0053]

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

[0054]

[0062] 5 shows a schematic diagram of a voltage contrast response of a wafer consistent with embodiments of the present disclosure. In some embodiments, physical and electrical defects in a wafer (e.g., resistive shorts and opens, deep trench capacitor defects, back-end-of-line (BEOL) defects, etc.) can be detected using voltage contrast methods in a charged particle inspection system. Defect detection using voltage contrast images can use a pre-scan process (i.e., charging, flooding, neutralization, or pre-treatment process) in which charged particles are applied to areas of the wafer to be inspected (e.g., sample 208 in FIG. 2A , wafer 150 in FIG. 2B ) prior to inspection.

[0055]

[0063] In some embodiments, an electron beam tool (e.g., electron beam tool 104 of FIG. 2A , electron beam tool 100B of FIG. 2B ) can be used to detect defects in internal or external structures of a wafer by irradiating the wafer with multiple beamlets of a primary electron beam (e.g., multiple beamlets 211, 212, or 213 of primary electron beam 202 of FIG. 2A , electron beam 161 of FIG. 2B , primary electron beam 312 of FIG. 3 , or electron beam 607 of FIG. 6 ) and measuring the voltage contrast response of the wafer to the irradiation. In some embodiments, the wafer can include a test device area 520 developed on a substrate 510. In some embodiments, the test device area 520 can include multiple device structures 530 and 540 separated by an insulating material 550. For example, the device structure 530 is connected to the substrate 510. In contrast, the device structure 540 is separated from the substrate 510 by an insulating material 550 such that a thin insulator structure 570 (eg, a thin oxide) exists between the device structure 540 and the substrate 510 .

[0056]

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

[0057]

[0065] 5, a positive potential may build up on the surface of the wafer. For example, after an electron beam tool scans the test device area 520 (e.g., during a pre-scan process), the device structure 440 may retain more positive charge because the device structure 540 is not connected to the electrical ground of the substrate 510, resulting in a positive potential on the surface of the device structure 540. In contrast, primary electrons with the same landing energy (i.e., the same yield rate) imparted to the device structure 530 may result in less positive charge being retained in the device structure 430 because the positive charge may be neutralized by electrons provided by the connection to the substrate 510.

[0058]

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

[0059]

[0067] An electron beam tool (e.g., multi-beam electron beam tool 104 of FIG. 2A or electron beam tool 100B of FIG. 2B) may pre-scan the surface of a wafer by supplying electrons to build up an electrical potential on the surface of the wafer. After pre-scanning the wafer, the electron beam tool may acquire images of multiple dies within the wafer. The pre-scan is applied to the wafer under the assumption that the surface potential built up on the wafer surface during the pre-scan will be maintained during inspection and will remain above the detection threshold of the electron beam tool.

[0060]

[0068] However, the accumulated surface potential level may change during inspection due to electrical breakdown or tunneling effects, resulting in undetectable defects. For example, when a high voltage is applied to a thin, highly resistive device structure (e.g., a thin oxide), such as insulator structure 570, leakage current may flow through the highly resistive structure, thereby preventing the structure from functioning as a perfect insulator. This may affect circuit functionality and result in device failure. Similar effects of leakage current may also occur in structures with improperly formed materials or highly resistive metal layers, such as a cobalt silicide (e.g., CoSi, CoSi2, Co2Si, Co3Si, etc.) layer between a tungsten plug and the source or drain area of ​​a field-effect transistor (FET).

[0061]

[0069] A faulty etching process can leave behind a thin oxide that results in an undesired electrical disconnection (e.g., an open circuit) between two structures intended to be electrically connected (e.g., device structure 540 and substrate 510). For example, device structures 430 and 440 may be designed to contact substrate 510 and function identically, but due to manufacturing errors, insulator structure 570 may be present in device structure 540. In this case, insulator structure 570 may exhibit defects that are prone to dielectric breakdown effects.

[0062]

[0070] Reference is now made to Figure 6, which is a schematic diagram of an exemplary charged particle system 600 consistent with embodiments of the present disclosure. The charged particle system 600 may include an inspection system or a metrology system.

[0063]

[0071] In some embodiments, the charged particle system 600 may include a light source L1 (e.g., the ACC module 320 in FIG. 3 ). The light source L1 may be an ACC module configured to emit one or more light beams 601 (e.g., a laser beam, the light beam 322 in FIG. 3 ). For example, the emitted light beam 601 may illuminate an area 603 of a sample 605 (e.g., the sample 208 in FIG. 2A , the wafer 150 in FIG. 2B , or the wafer 340 in FIG. 3 ), thereby adjusting or controlling the charge accumulated in the area of ​​the sample 605. In some embodiments, the charged particle system 600 may include a mirror system configured to adjust an angle of incidence θ (e.g., the angle of incidence θ in FIG. 3 ) of the light beam 601 to the sample 605 during inspection of the sample 605 without substantially adjusting the position or area 603 of the light beam 601 on the sample 605 (e.g., adjusting the position or area of ​​the light beam on the sample by less than 10 μm). In some embodiments, the mirror system is configured to adjust the angle of incidence θ of the light beam 601 based on the material of the sample 605 (e.g., by adjusting the position of one or more mirrors of the mirror system).

[0064]

[0072] In some embodiments, the mirror system may include a tiltable flat mirror (e.g., a flat mirror configured to tilt) M1, a first parabolic mirror P1, and a second parabolic mirror P2. In some embodiments, the tiltable flat mirror M1 may be a MEMS mirror. In some embodiments, the tiltable flat mirror M1 may be a motorized tiltable flat mirror. In some embodiments, one or both of the first parabolic mirror P1 and the second parabolic mirror P2 may be spherical mirrors. In some embodiments, the tiltable flat mirror M1 may be configured to receive the light beam 601 from the light source L1 and adjustably reflect the light beam 601 to the first parabolic mirror P1. For example, the tiltable flat mirror M1 may be adjusted so that the light beam 601 emitted from the light source L1 may follow a variety of different paths (e.g., path 611, path 612, etc.). In some embodiments, the adjustable reflection of the light beam 601 may result in an adjustment of the angle of incidence θ of the light beam 601 with respect to the sample 605. Advantageously, in some embodiments, the angle of incidence θ can be adjusted by adjusting only the tiltable plane mirror M1.

[0065]

[0073] In some embodiments, the first parabolic mirror P1 may be configured to receive the light beam 601 reflected from the tiltable flat mirror M1 and reflect the light beam 601 to the second parabolic mirror P2, which may be configured to receive the light beam 601 reflected from the first parabolic mirror P1 and reflect the light beam 601 to the sample 605. In some embodiments, the first parabolic mirror P1 may extend to point 621 or point 622. In some embodiments, the second parabolic mirror P2 may extend to point 631 or point 632. In some embodiments, the second parabolic mirror P2 may be configured to provide an unobstructed path for the electron beam 607 (e.g., multiple beamlets 211, 212, or 213 of the primary electron beam 202 in FIG. 2A , the electron beam 161 in FIG. 2B , the primary electron beam 312 in FIG. 3 ) to land on the sample 605.

[0066]

[0074] In some embodiments, the light beam 601 may be multiple light beams, and the first parabolic mirror P1 may be configured to collimate the multiple light beams. In some embodiments, the distance between the first parabolic mirror P1 and the second parabolic mirror P2 may be adjusted without affecting one or more light beams. In some embodiments, the first parabolic mirror P1 may be configured to reflect the light beam 601 through a window W1, with the first parabolic mirror P1 on a first side of the window W1 and the second parabolic mirror P2 on a second side of the window W1. In some embodiments, the first side of the window W1 may be in an ambient environment, and the second side of the window W1 may be in a vacuum environment.

[0067]

[0075] In some embodiments, the position or area 603 of the light beam 601 on the sample 605 may coincide with the position or area of ​​the electron beam 607 on the sample 605. In some embodiments, the configuration of the charged particle system 600 may advantageously provide a smaller light beam spot on the sample 605, thereby resulting in a higher light beam density on the sample 605 (e.g., about 10 times greater than the light beam density in typical systems).

[0068]

[0076] Reference is now made to FIG. 7, which is an exemplary graph 700, consistent with an embodiment of the present disclosure.

[0069]

[0077] Graph 700 may include a dispersion curve L0 of a free-space light beam emitted from an ACC module (e.g., ACC module 320 in FIG. 3 , light source L1 in FIG. 6 ). Graph 700 may also include dispersion curves S1, S2, and S3 corresponding to the relationship between the light beam emitted from the ACC module (e.g., light beam 322 in FIG. 3 , light beam 601 in FIG. 6 ) and a sample (e.g., sample 208 in FIG. 2A , wafer 150 in FIG. 2B , wafer 340 in FIG. 3 , sample 605 in FIG. 6 ). Dispersion curves S1, S2, and S3 may each correspond to a different sample material.

[0070]

[0078] Axis 701 of graph 700 may correspond to the wavelength ω of the light beam emitted from the ACC module. Axis 703 of graph 700 may correspond to the momentum k in the "x" direction of the light beam emitted from the ACC module. x where the "x" direction is along the surface of the sample from a top view of the sample.

[0071]

[0079] Wavelength ω and momentum k of the light beam emitted from the ACC module x The relationship can be described by the following equation: ω=c·k x =c·k·sin(θ) (1) where c is the speed of light, k is the free-space momentum of light, and θ is the angle of incidence θ of the light beam on the sample (e.g., angle of incidence θ in FIG. 3, angle of incidence θ in FIG. 6). As shown in equation (1) above, momentum k x is related to the angle of incidence θ.

[0072]

[0080] The intersection of the dispersion curve of the sample material (e.g., dispersion curve S1, S2, or S3) with the dispersion curve L0 of the free-space light beam corresponds to a higher light coupling efficiency. The light coupling efficiency may represent the number of photons (e.g., from light beam 322 in FIG. 3 or light beam 601 in FIG. 6) that couple to the sample. That is, an incidence angle that results in the sample's dispersion curve intersecting L0 may indicate a higher number of photons emitted from the ACC module that couple to the sample. In some embodiments, the incidence angle may be adjusted to maximize or increase the number of photons emitted from the ACC module that couple to the sample.

[0073]

[0081] Thus, the angle of incidence of the light beam emitted from the ACC module can be adjusted to enhance light coupling efficiency for different sample materials under examination.

[0074]

[0082] Reference is now made to Figure 8, which illustrates an exemplary process 800 consistent with embodiments of the present disclosure. The steps of process 800 may be performed by a system (e.g., charged particle system 600 of Figure 6), for illustrative purposes. It is understood that the illustrated process 800 may be modified to modify the order of the steps and to include additional steps that may be performed by the system.

[0075]

[0083] In step 801, a light source (e.g., ACC module 320 in FIG. 3 , light source L1 in FIG. 6 ) may be configured to emit a light beam (e.g., a laser beam, light beam 322 in FIG. 3 , light beam 601 in FIG. 6 ). In some embodiments, the light source may be an ACC module configured to emit one or more light beams. For example, the emitted light beam may illuminate an area (e.g., area 603 in FIG. 6 ) of a sample (e.g., sample 208 in FIG. 2A , wafer 150 in FIG. 2B , wafer 340 in FIG. 3 , sample 605 in FIG. 6 ), thereby adjusting or controlling the charge accumulated in the area of ​​the sample.

[0076]

[0084] In step 803, the mirror system may adjust the angle of incidence of the light beam on the sample (e.g., angle of incidence θ in FIG. 3 , angle of incidence θ in FIG. 6 ) during inspection of the sample without substantially adjusting the position or area of ​​the light beam on the sample. In some embodiments, the mirror system is configured to adjust the angle of incidence of the light beam based on the material of the sample.

[0077]

[0085] In some embodiments, the mirror system may include a tiltable flat mirror (e.g., a flat mirror configured to tilt, tiltable flat mirror M1 in FIG. 6 ), a first parabolic mirror (e.g., first parabolic mirror P1 in FIG. 6 ), and a second parabolic mirror (e.g., second parabolic mirror P2 in FIG. 6 ). In some embodiments, the tiltable flat mirror may be a MEMS mirror. In some embodiments, the tiltable flat mirror may be configured to receive a light beam from a light source and adjustably reflect the light beam to the first parabolic mirror. For example, the tiltable flat mirror may be adjusted so that the light beam emitted from the light source may follow a variety of different paths (e.g., paths 611-612 in FIG. 6 ). In some embodiments, the adjustable reflection of the light beam may result in an adjustment of the angle of incidence of the light beam on the sample. Advantageously, in some embodiments, the angle of incidence may be adjusted solely by adjusting the tiltable flat mirror.

[0078]

[0086] In some embodiments, the first parabolic mirror may be configured to receive the light beam reflected from the tiltable flat mirror and reflect the light beam to the second parabolic mirror, which may be configured to receive the light beam reflected from the first parabolic mirror and reflect the light beam to the sample. In some embodiments, the second parabolic mirror may be configured to provide an unobstructed path for the electron beam (e.g., multiple beamlets 211, 212, or 213 of primary electron beam 202 in FIG. 2A , electron beam 161 in FIG. 2B , primary electron beam 312 in FIG. 3 , electron beam 607 in FIG. 6 ) to land on the sample.

[0079]

[0087] In some embodiments, the light beam may be multiple light beams, and the first parabolic mirror may be configured to collimate the multiple light beams. In some embodiments, the distance between the first parabolic mirror and the second parabolic mirror may be adjusted without affecting the one or more light beams. In some embodiments, the first parabolic mirror may be configured to reflect the light beam through a window (e.g., window W1 in FIG. 6), with the first parabolic mirror on a first side of the window and the second parabolic mirror on a second side of the window. In some embodiments, the first side of the window may be in an ambient environment and the second side of the window may be in a vacuum environment.

[0080]

[0088] In some embodiments, the position or area of ​​the light beam on the sample may coincide with the position or area of ​​the electron beam on the sample. In some embodiments, the configuration of the charged particle system may advantageously provide a smaller light beam spot on the sample, thereby resulting in a higher light beam density on the sample (e.g., about 10 times greater than the light beam density in typical systems).

[0081]

[0089] Consistent with embodiments herein, a non-transitory computer-readable medium may be provided that stores instructions for a processor of a controller (e.g., controller 109 of FIG. 1 ) to control an electron beam tool or a mirror (e.g., tiltable planar mirror M1 of FIG. 6 ) to adjust the angle of incidence of a light beam on a sample. These instructions may enable one or more processors to perform operations of an ACC module, operation of a mirror system, image processing, data processing, beamlet scanning, graphical display, operation of a charged particle beam instrument, or operation of another imaging device, etc. In some embodiments, a non-transitory computer-readable medium may be provided that stores instructions for a processor to perform the steps of process 800. Common forms of non-transitory media include, for example, floppy disks, flexible disks, hard disks, solid state drives, magnetic tape or any other magnetic data storage medium, compact disk read-only memory (CD-ROM), any other optical data storage medium, any physical medium with a pattern of holes, random access memory (RAM), programmable read-only memory (PROM) and erasable programmable read-only memory (EPROM), or any other flash memory, non-volatile random access memory (NVRAM), cache, registers, any other memory chip or cartridge, and networked versions of the foregoing.

[0082]

[0090] The embodiments may be further described using the following clauses. 1. A system comprising: a light source configured to emit a light beam; a mirror system configured to adjust the angle of incidence of the light beam on the sample during inspection of the sample without substantially adjusting the position of the light beam on the sample; and Including, the system. 2. The mirror system is a tiltable flat mirror; a first parabolic mirror; a second parabolic mirror; 2. The system of claim 1, comprising: 3. the tiltable flat mirror is configured to receive the light beam from the light source and adjustably reflect the light beam onto the first parabolic mirror, the adjustable reflection of the light beam providing an adjustment to the angle of incidence of the light beam onto the sample; the first parabolic mirror is configured to receive the light beam reflected from the tiltable flat mirror and reflect the light beam to the second parabolic mirror; 3. The system of claim 2, wherein the second parabolic mirror is configured to receive the light beam reflected from the first parabolic mirror and reflect the light beam to the sample. 4. The system of clause 2 or 3, wherein the light beam comprises a plurality of light beams, and the first parabolic mirror is configured to collimate the plurality of light beams. 5. A system described in any one of clauses 2 to 4, wherein the first parabolic mirror is configured to reflect the light beam through a window, the first parabolic mirror being on a first side of the window, and the second parabolic mirror being on a second side of the window. 6. The system of clause 5, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 7. The system of any one of clauses 2 to 6, wherein the tiltable flat mirror is a MEMS mirror. 8. The system of any one of clauses 1-7, wherein the mirror system is configured to adjust the angle of incidence of the light beam based on the material of the sample. 9. A system according to any one of clauses 1 to 8, wherein the position of the light beam on the sample coincides with the position of the electron beam on the sample. 10. A system comprising: a module configured to emit a beam that illuminates an area on the sample; a mirror system configured to adjust the angle of the beam irradiating the sample without substantially adjusting the position of the beam irradiating the sample; and Including, the system. 11. The system of clause 10, wherein the module includes a light source. 12. The mirror system is a tiltable flat mirror; a first parabolic mirror; a second parabolic mirror; 12. The system of clause 10 or 11, comprising: 13. The tiltable plane mirror is configured to receive the beam from the module and adjustably reflect the beam onto the first parabolic mirror, the adjustable reflection of the beam providing an adjustment to the angle of incidence of the beam on the sample; the first parabolic mirror is configured to receive the beam reflected from the tiltable planar mirror and reflect the beam onto the second parabolic mirror; 13. The system of claim 12, wherein the second parabolic mirror is configured to receive the beam reflected from the first parabolic mirror and reflect the beam onto the sample. 14. The system of clause 12 or 13, wherein the beam comprises a plurality of beams, and the first parabolic mirror is configured to collimate the plurality of beams. 15. A system described in any one of clauses 12 to 14, wherein a first parabolic mirror is configured to reflect the beam through a window, the first parabolic mirror being on a first side of the window, and the second parabolic mirror being on a second side of the window. 16. The system of clause 15, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 17. A system according to any one of clauses 12 to 16, wherein the tiltable flat mirror is a MEMS mirror. 18. The system of any one of clauses 10-17, wherein the mirror system is configured to adjust the angle of incidence of the beam based on the material of the sample. 19. A system according to any one of clauses 10 to 18, wherein the position of the beam on the sample coincides with the position of the electron beam on the sample. 20. A system comprising: a module configured to emit a beam that illuminates an area on the sample; a mirror system including a first mirror having an adjustable position for adjusting the angle of the beam irradiating the sample without substantially adjusting the position of the beam irradiating the sample; Including, the system. 21. The first mirror includes a tiltable flat mirror, and the mirror system includes: a first parabolic mirror; a second parabolic mirror; 21. The system of clause 20, further comprising: 22. The tiltable plane mirror is configured to receive the beam from the module and adjustably reflect the beam onto the first parabolic mirror, the adjustable reflection of the beam providing an adjustment to the angle of incidence of the beam on the sample; the first parabolic mirror is configured to receive the beam reflected from the tiltable planar mirror and reflect the beam onto the second parabolic mirror; 22. The system of claim 21, wherein the second parabolic mirror is configured to receive the beam reflected from the first parabolic mirror and reflect the beam onto the sample. 23. The system of clause 21 or 22, wherein the beam comprises a plurality of beams, and the first parabolic mirror is configured to collimate the plurality of beams. 24. A system described in any one of clauses 21 to 23, wherein a first parabolic mirror is configured to reflect the beam through a window, the first parabolic mirror being on a first side of the window, and the second parabolic mirror being on a second side of the window. 25. The system of clause 24, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 26. A system according to any one of clauses 21 to 25, wherein the tiltable flat mirror is a MEMS mirror. 27. The system of any one of clauses 20-26, wherein the mirror system is configured to adjust the angle of the beam based on the material of the sample. 28. A system according to any one of clauses 20 to 27, wherein the position of the beam on the sample coincides with the position of the electron beam on the sample. 29. A non-transitory computer-readable medium, comprising: A non-transitory computer-readable medium comprising a set of instructions executable by one or more processors of an apparatus including a light source configured to emit a light beam to cause the apparatus to perform a method comprising adjusting a position of a mirror system to adjust an angle of incidence of the light beam on a sample during inspection of the sample without substantially adjusting the position of the light beam on the sample. 30. The mirror system is a tiltable flat mirror; a first parabolic mirror; a second parabolic mirror; 29. A non-transitory computer-readable medium as set forth in clause 29, comprising: 31. A set of instructions is receiving a light beam from the light source by a tiltable flat mirror and adjustably reflecting the light beam onto a first parabolic mirror, wherein the adjustable reflection of the light beam results in an adjustment to the angle of incidence of the light beam on the sample; receiving the light beam reflected from the tiltable flat mirror by a first parabolic mirror and reflecting the light beam onto a second parabolic mirror; receiving the light beam reflected from the first parabolic mirror by a second parabolic mirror and reflecting the light beam onto the sample; 30. The non-transitory computer-readable medium of clause 29, executable by one or more processors of the device to cause the device to further execute. 32. The non-transitory computer-readable medium of clause 30 or 31, wherein the light beam includes a plurality of light beams, and the first parabolic mirror is configured to collimate the plurality of light beams. 33. The non-transitory computer-readable medium of any one of clauses 30-32, wherein the set of instructions is executable by one or more processors of the device to further cause the device to reflect the light beam through a window by a first parabolic mirror, the first parabolic mirror being on a first side of the window, and the second parabolic mirror being on a second side of the window. 34. The non-transitory computer-readable medium of clause 33, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 35. The non-transitory computer-readable medium of any one of clauses 30 to 34, wherein the tiltable flat mirror is a MEMS mirror. 36. The non-transitory computer-readable medium of any one of clauses 29 to 35, wherein the set of instructions is executable by one or more processors of the device to further cause the device to adjust the angle of incidence of the light beam with a mirror system based on the material of the sample. 37. The non-transitory computer-readable medium of any one of clauses 29-36, wherein the position of the light beam on the sample coincides with the position of the electron beam on the sample. 38. A non-transitory computer-readable medium, comprising: A non-transitory computer-readable medium comprising a set of instructions executable by one or more processors of an apparatus comprising a module configured to emit a beam to cause the apparatus to perform a method comprising adjusting a position of a mirror system to adjust an angle of the beam that irradiates a sample without substantially adjusting the irradiation position of the beam on the sample. 39. The non-transitory computer-readable medium of clause 38, wherein the module includes a light source. 40. The mirror system is a tiltable flat mirror; a first parabolic mirror; a second parabolic mirror; 39. A non-transitory computer-readable medium according to clause 38 or 39, comprising: 41. A set of instructions is receiving the beam from the module by a tiltable flat mirror and adjustably reflecting the beam onto a first parabolic mirror, where the adjustable reflection of the beam results in adjustment to the angle of incidence of the beam on the sample; receiving the beam reflected from the tiltable flat mirror by a first parabolic mirror and reflecting the beam onto a second parabolic mirror; receiving the beam reflected from the first parabolic mirror by a second parabolic mirror and reflecting the beam onto the sample; 41. The non-transitory computer-readable medium of clause 40, executable by one or more processors of the device to cause the device to further perform. 42. The non-transitory computer-readable medium of clause 40 or 41, wherein the beam comprises a plurality of beams, and the first parabolic mirror is configured to collimate the plurality of beams. 43. The non-transitory computer-readable medium of any one of clauses 40-42, wherein the set of instructions is executable by one or more processors of the device to further cause the device to reflect the beam through a window by a first parabolic mirror, the first parabolic mirror being on a first side of the window, and the second parabolic mirror being on a second side of the window. 44. The non-transitory computer-readable medium of clause 43, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 45. The non-transitory computer-readable medium of any one of clauses 40-44, wherein the tiltable flat mirror is a MEMS mirror. 46. ​​The non-transitory computer-readable medium of any one of clauses 38 to 45, wherein the set of instructions is executable by one or more processors of the device to further cause the device to adjust the angle of incidence of the beam with a mirror system based on the material of the sample. 47. The non-transitory computer-readable medium of any one of clauses 38-46, wherein the position of the beam on the sample coincides with the position of the electron beam on the sample. 48. A non-transitory computer-readable medium, comprising: A non-transitory computer-readable medium comprising a set of instructions executable by one or more processors of an apparatus including a module configured to emit a beam to cause the apparatus to perform a method comprising adjusting a position of a first mirror of a mirror system to adjust an angle of the beam that irradiates a sample without substantially adjusting the position of the beam irradiating the sample. 49. The first mirror includes a tiltable flat mirror, and the mirror system includes: a first parabolic mirror; a second parabolic mirror; 49. The non-transitory computer-readable medium of clause 48, further comprising: 50. One set of instructions is receiving the beam from the module by a tiltable flat mirror and adjustably reflecting the beam onto a first parabolic mirror, where the adjustable reflection of the beam results in adjustment to the angle of incidence of the beam on the sample; receiving the beam reflected from the tiltable flat mirror by a first parabolic mirror and reflecting the beam onto a second parabolic mirror; receiving the beam reflected from the first parabolic mirror by a second parabolic mirror and reflecting the beam onto the sample; 49. A non-transitory computer-readable medium as described in clause 49, executable by one or more processors of the device to cause the device to further perform the 51. The non-transitory computer-readable medium of clause 49 or 50, wherein the beam comprises a plurality of beams, and the first parabolic mirror is configured to collimate the plurality of beams. 52. The non-transitory computer-readable medium of any one of clauses 49 to 51, wherein the set of instructions is executable by one or more processors of the device to further cause the device to reflect the beam through a window by a first parabolic mirror, the first parabolic mirror being on a first side of the window, and the second parabolic mirror being on a second side of the window. 53. The non-transitory computer-readable medium of clause 52, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 54. The non-transitory computer-readable medium of any one of clauses 49 to 53, wherein the tiltable flat mirror is a MEMS mirror. 55. The non-transitory computer-readable medium of any one of clauses 48 to 54, wherein the set of instructions is executable by one or more processors of the device to further cause the device to adjust the angle of the beam with a mirror system based on the material of the sample. 56. The non-transitory computer-readable medium of any one of clauses 48-55, wherein the position of the beam on the sample coincides with the position of the electron beam on the sample. 57. A non-transitory computer-readable medium, comprising: A non-transitory computer-readable medium comprising a set of instructions executable by one or more processors of an apparatus including a light source configured to emit a light beam to cause the apparatus to perform a method including adjusting a position of a first mirror system based on a material of the sample to adjust an angle of incidence of the light beam on the sample during inspection of the sample without substantially adjusting a position of the light beam on the sample. 58. The first mirror comprises a tiltable flat mirror of a mirror system, the mirror system comprising: a first parabolic mirror; a second parabolic mirror; 58. The non-transitory computer-readable medium of clause 57, further comprising: 59. A set of instructions is receiving a beam from the light source by a tiltable flat mirror and adjustably reflecting the light beam onto a first parabolic mirror, wherein the adjustable reflection of the light beam results in adjustment to the angle of incidence of the light beam on the sample; receiving the light beam reflected from the tiltable flat mirror by a first parabolic mirror and reflecting the light beam onto a second parabolic mirror; receiving the light beam reflected from the first parabolic mirror by a second parabolic mirror and reflecting the light beam onto the sample; 59. The non-transitory computer-readable medium of clause 58, executable by one or more processors of the device to cause the device to further perform. 60. The non-transitory computer-readable medium of clause 58 or 59, wherein the light beam includes a plurality of light beams, and the first parabolic mirror is configured to collimate the plurality of light beams. 61. The non-transitory computer-readable medium of any one of clauses 58 to 60, wherein the set of instructions is executable by one or more processors of the device to further cause the device to reflect the light beam through a window by a first parabolic mirror, the first parabolic mirror being on a first side of the window, and the second parabolic mirror being on a second side of the window. 62. The non-transitory computer-readable medium of clause 61, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 63. The non-transitory computer-readable medium of any one of clauses 58-62, wherein the tiltable flat mirror is a MEMS mirror. 64. The non-transitory computer-readable medium of any one of clauses 57-63, wherein the set of instructions is executable by one or more processors of the device to further cause the device to adjust the angle of the light beam with a mirror system based on the material of the sample. 65. The non-transitory computer-readable medium of any one of clauses 57-64, wherein the position of the light beam on the sample coincides with the position of the electron beam on the sample. 66. A method of an apparatus including a light source configured to emit a light beam, the method comprising: A method comprising adjusting a position of a mirror system to adjust an angle of incidence of a light beam on a sample during inspection of the sample without substantially adjusting the position of the light beam on the sample. 67. The mirror system is a tiltable flat mirror; a first parabolic mirror; a second parabolic mirror; 67. The method of claim 66, including: 68. Adjustably reflecting by a tiltable flat mirror receiving a light beam from a light source and adjustably reflecting the light beam to a first parabolic mirror, wherein the adjustable reflection of the light beam results in adjustment to the angle of incidence of the light beam on the sample; receiving the light beam reflected from the tiltable flat mirror by a first parabolic mirror and reflecting the light beam onto a second parabolic mirror; receiving the light beam reflected from the first parabolic mirror by a second parabolic mirror and reflecting the light beam onto the sample; 68. The method of clause 67, further comprising: 69. The method of clause 67 or 68, wherein the light beam comprises a plurality of light beams, and the first parabolic mirror is configured to collimate the plurality of light beams. 70. The method of any one of clauses 67-69, further comprising reflecting the light beam through the window with a first parabolic mirror, the first parabolic mirror being on a first side of the window and the second parabolic mirror being on a second side of the window. 71. The method of clause 70, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 72. The method of any one of clauses 67-71, wherein the tiltable flat mirror is a MEMS mirror. 73. The method of any one of clauses 66-72, further comprising adjusting the angle of incidence of the light beam with a mirror system based on the material of the sample. 74. The method of any one of clauses 66 to 73, wherein the position of the light beam on the sample coincides with the position of the electron beam on the sample. 75. A method of an apparatus including a module configured to emit a beam, the apparatus for the method comprising: A method comprising adjusting a position of a mirror system to adjust an angle of a beam that illuminates a sample without substantially adjusting the position of the beam on the sample. 76. The method of clause 75, wherein the module includes a light source. 77. The mirror system is a tiltable flat mirror; a first parabolic mirror; a second parabolic mirror; 77. The method of claim 75 or 76, comprising: 78. Adjustably reflecting by a tiltable flat mirror receiving a beam from the module and adjustably reflecting the beam onto a first parabolic mirror, wherein the adjustable reflection of the beam results in adjustment to the angle of incidence of the beam on the sample; receiving the beam reflected from the tiltable flat mirror by a first parabolic mirror and reflecting the beam onto a second parabolic mirror; receiving the beam reflected from the first parabolic mirror by a second parabolic mirror and reflecting the beam onto the sample; 78. The method of clause 77, further comprising: 79. The method of clause 77 or 78, wherein the beam comprises a plurality of beams, and the first parabolic mirror is configured to collimate the plurality of beams. 80. The method of any one of clauses 77-79, further comprising reflecting the beam through a window with a first parabolic mirror, the first parabolic mirror being on a first side of the window and the second parabolic mirror being on a second side of the window. 81. The method of clause 80, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 82. The method of any one of clauses 77-81, wherein the tiltable flat mirror is a MEMS mirror. 83. The method of any one of clauses 75-82, further comprising adjusting the angle of incidence of the beam with a mirror system based on the material of the sample. 84. The method of any one of clauses 75 to 83, wherein the position of the beam on the sample coincides with the position of the electron beam on the sample. 85. A method of an apparatus including a module configured to emit a beam, the method comprising: A method comprising adjusting a position of a first mirror of a mirror system to adjust an angle of a beam that illuminates a sample without substantially adjusting a position of the beam that illuminates the sample. 86. The first mirror includes a tiltable flat mirror, and the mirror system includes: a first physical surface mirror; and a second physical plane mirror; 86. The method of clause 85, further comprising: 87. Adjustably reflecting by a tiltable plane mirror receiving a beam from the module and adjustably reflecting the beam to a first physical surface mirror, wherein the adjustable reflection of the beam results in adjustment to the angle of incidence of the beam on the sample; receiving the beam reflected from the tiltable flat mirror by a first parabolic mirror and reflecting the beam onto a second parabolic mirror; receiving the beam reflected from the first parabolic mirror by a second parabolic mirror and reflecting the beam onto the sample; 87. The method of clause 86, further comprising: 88. The method of clause 86 or 87, wherein the beam comprises a plurality of beams, and the first parabolic mirror is configured to collimate the plurality of beams. 89. The method of any one of clauses 86-88, further comprising reflecting the beam through a window with a first parabolic mirror, the first parabolic mirror being on a first side of the window and the second parabolic mirror being on a second side of the window. 90. The method of clause 89, wherein a first side of the window is in an ambient environment and a second side of the window is in a vacuum environment. 91. The method of any one of clauses 86-90, wherein the tiltable flat mirror is a MEMS mirror. 92. The method of any one of clauses 85-91, further comprising adjusting the angle of the beam with a mirror system based on the material of the sample. 93. The method of any one of clauses 85-92, wherein the position of the beam on the sample coincides with the position of the electron beam on the sample.

[0083]

[0091] It will be understood that the embodiments of the present disclosure are not limited to the exact constructions described above and illustrated in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. 1. A system comprising: a light source configured to emit a light beam; a mirror system configured to adjust the angle of incidence of the light beam on the sample during inspection of the sample without substantially adjusting the position of the light beam on the sample; and Including, the system.

2. The mirror system includes: a tiltable flat mirror; a first parabolic mirror; a second parabolic mirror; and The system of claim 1 , comprising:

3. the tiltable flat mirror is configured to receive the light beam from the light source and adjustably reflect the light beam onto the first parabolic mirror, the adjustable reflection of the light beam causing an adjustment to the angle of incidence of the light beam on the sample; the first parabolic mirror is configured to receive the light beam reflected from the tiltable flat mirror and reflect the light beam to the second parabolic mirror; the second parabolic mirror is configured to receive the light beam reflected from the first parabolic mirror and reflect the light beam to the sample. The system of claim 2 .

4. The system of claim 2 , wherein the light beam comprises a plurality of light beams, and the first parabolic mirror is configured to collimate the plurality of light beams.

5. 3. The system of claim 2, wherein the first parabolic mirror is configured to reflect the light beam through a window, the first parabolic mirror being on a first side of the window and the second parabolic mirror being on a second side of the window.

6. The system of claim 5 , wherein the first side of the window is in an ambient environment and the second side of the window is in a vacuum environment.

7. The system of claim 2 , wherein the tiltable planar mirror is a MEMS mirror.

8. The system of claim 1 , wherein the mirror system is configured to adjust the angle of incidence of the light beam based on the material of the sample.

9. The system of claim 1 , wherein the position of the light beam on the sample coincides with the position of the electron beam on the sample.

10. A non-transitory computer-readable medium, comprising:

1. A non-transitory computer-readable medium comprising a set of instructions executable by one or more processors of an apparatus comprising a module configured to emit a beam to cause the apparatus to perform a method comprising adjusting a position of a first mirror of a mirror system to adjust an angle of the beam that irradiates a sample without substantially adjusting a position of the beam irradiating the sample.

11. the first mirror includes a tiltable flat mirror, and the mirror system includes: a first parabolic mirror; a second parabolic mirror; and The non-transitory computer-readable medium of claim 10 further comprising:

12. The set of instructions comprises: receiving the beam from the module by the tiltable flat mirror and adjustably reflecting the beam onto the first parabolic mirror, wherein the adjustable reflection of the beam results in adjustment to the angle of the beam to the sample; receiving the beam reflected from the tiltable flat mirror by the first parabolic mirror and reflecting the beam onto the second parabolic mirror; receiving the beam reflected from the first parabolic mirror and reflecting the beam onto the sample by the second parabolic mirror; 12. The non-transitory computer-readable medium of claim 11, executable by one or more processors of the device to cause the device to further execute:

13. 12. The non-transitory computer-readable medium of claim 11, wherein the set of instructions is executable by one or more processors of the device to further cause the device to reflect the beam through a window with the first parabolic mirror, the first parabolic mirror being on a first side of the window and the second parabolic mirror being on a second side of the window.

14. 11. The non-transitory computer-readable medium of claim 10, wherein the set of instructions is executable by one or more processors of the device to further cause the device to adjust the angle of the beam with the mirror system based on a material of the sample.

15. The non-transitory computer-readable medium of claim 10 , wherein the position of the beam on the sample coincides with a position of an electron beam on the sample.

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