Beam position displacement correction in charged particle inspection

Abstract

This invention discloses an improved method and system for correcting errors in inspection images. One improved method includes: acquiring a first beam position set on the test wafer while a wafer stage supporting a test wafer moves at a first speed; acquiring a second beam position set on the test wafer corresponding to the first beam position set while the wafer stage moves at a second speed; calculating a beam position displacement of a beam while the wafer stage moves at a third speed within the range of the first speed to the second speed; and adjusting the beam position of the beam based on the calculated beam position displacement.

Description

Technical Field

[0001] The embodiments provided herein relate to an image enhancement technique, and more particularly, to a beam position displacement calibration or correction for charged particle detection. Prior Art

[0002] In the manufacturing process of an integrated circuit (IC), incomplete or completed circuit components are detected to ensure that they are manufactured according to the design and are defect-free. Detection systems using an optical microscope or a charged particle (e.g., electron) beam microscope, such as a scanning electron microscope (SEM), can be employed. As the physical size of IC components continues to shrink, accuracy and yield in defect detection become increasingly important. Detection images such as SEM images can be used to identify or classify defects in the manufactured IC. To improve defect detection performance, accurate SEM images without distortion or deformation are required. Summary of the Invention

[0003] The embodiments provided herein disclose a particle beam detection device, and more particularly, disclose a detection device using a plurality of charged particle beams.

[0004] Some embodiments provide a method for correcting detection image errors. The method includes: acquiring a first set of beam positions on the test wafer while a wafer stage supporting a test wafer moves at a first speed; acquiring a second set of beam positions on the test wafer corresponding to the first set of beam positions while the wafer stage moves at a second speed; calculating a beam position displacement of a beam while the wafer stage moves at a third speed within a speed range from the first speed to the second speed; and adjusting a beam position of the beam based on the calculated beam position displacement.

[0005] Some embodiments provide a device for correcting detection image errors. The device includes: a memory storing an instruction set, and at least one processor configured to execute the instruction set to cause the device to perform the following operations: acquiring a first set of beam positions on the test wafer while a wafer stage supporting a test wafer moves at a first speed; acquiring a second set of beam positions on the test wafer corresponding to the first set of beam positions while the wafer stage moves at a second speed; calculating a beam position displacement of a beam while the wafer stage moves at a third speed within a speed range from the first speed to the second speed; and adjusting a beam position of the beam based on the calculated beam position displacement.

[0006] Other advantages of the embodiments of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings, in which certain embodiments of the invention are illustrated by way of illustration and example. Brief Description of the Drawings

[0007] The above and other aspects of the present disclosure will become more apparent from the description of the exemplary embodiments taken in conjunction with the accompanying drawings.

[0008] FIG. 1 is a schematic diagram illustrating an example charged particle beam detection system consistent with an embodiment of the present disclosure.

[0009] FIG. 2 is a schematic diagram illustrating an example multi-beam tool that can be part of the example charged particle beam detection system of FIG. 1 consistent with an embodiment of the present disclosure.

[0010] FIG. 3 illustrates a magnetic field generation system of a detection device consistent with an embodiment of the present disclosure.

[0011] FIG. 4A illustrates a static magnetic field induced by the magnetic field generation system of FIG. 3 consistent with an embodiment of the present disclosure.

[0012] FIG. 4B illustrates eddy currents in a conductor generated by the movement of a wafer stage consistent with an embodiment of the present disclosure.

[0013] FIG. 4C illustrates an interference magnetic field induced by the eddy currents in the conductor consistent with an embodiment of the present disclosure.

[0014] FIG. 5 is a block diagram of a beam displacement compensation system consistent with an embodiment of the present disclosure.

[0015] FIG. 6A illustrates an example first detection image according to some embodiments of the present disclosure.

[0016] FIG. 6B illustrates an example second detection image according to some embodiments of the present disclosure.

[0017] FIG. 6C illustrates the beam position displacement of a second beam relative to a first beam consistent with some embodiments of the present disclosure.

[0018] FIG. 7 illustrates an example beam displacement table consistent with some embodiments of the present disclosure.

[0019] FIG. 8 is a process flow diagram showing an exemplary beam displacement compensation method consistent with an embodiment of the present disclosure. Embodiments

[0020] Now, exemplary embodiments will be described in detail, and examples of such exemplary embodiments will be illustrated in the accompanying drawings. The following description refers to the accompanying drawings, where like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following description of the exemplary embodiments do not represent all embodiments. In fact, they are only examples of devices and methods consistent with aspects related to the disclosed embodiments as described within the scope of the accompanying patent application. For example, although some embodiments are described in the context of using electron beams, the present disclosure is not limited thereto. Other types of charged particle beams can be similarly applied. In addition, other imaging systems can be used, such as optical imaging, photodetection, x-ray detection, etc.

[0021] An electronic device is constructed of circuits formed on a sheet of semiconductor material called a substrate. The semiconductor material can include, for example, silicon, gallium arsenide, indium phosphide, or silicon germanium or the like. Many circuits can be formed together on the same silicon wafer and are called integrated circuits or ICs. The size of these circuits has been significantly reduced such that many circuits in the circuit can fit on the substrate. For example, an IC chip in a smartphone can be as small as a thumbnail and still include over 2 billion transistors, each transistor being smaller than 1 / 1000 the size of a human hair.

[0022] Manufacturing such ICs with extremely small structures or components is a complex, time-consuming, and expensive process that often involves hundreds of individual steps. Even an error in one step has the potential to produce defects in the finished IC, rendering the finished IC useless. Therefore, one goal of the manufacturing process is to avoid such defects to maximize the number of functional ICs produced in the process, that is, to improve the overall yield of the process.

[0023] One component of improving the yield is to monitor the wafer manufacturing process to ensure that it is producing a sufficient number of functional integrated circuits. One way to monitor the process is to detect the wafer circuit structure at various stages of its formation. A scanning charged particle microscope (SCPM) can be used for the detection. For example, the SCPM can be a scanning electron microscope (SEM). The SCPM can be used to actually image these extremely small structures, thereby obtaining an "image" of the structure of the wafer. The image can be used to determine whether the structure is properly formed in the proper position. If the structure is defective, the process can be adjusted so that the defect is unlikely to recur.

[0024] As the physical size of IC components continues to shrink, accuracy and yield in defect detection become increasingly important. Detection images such as SEM images can be used to identify or classify defects in manufactured ICs. To improve defect detection performance, accurate SEM images without distortion or deformation are needed. During operation, a system magnetic field is formed around or within the SEM tool, and thus when a wafer stage including conductors moves in the system magnetic field, eddy currents can be induced in the conductors. By the induced eddy currents, a magnetic field that interferes with the system magnetic field of the SEM tool can be generated. Such magnetic field interference can cause the charged particle beam on the sample to be displaced from the target position, which in turn can reduce the image quality of the resulting SEM image. To strive to avoid generating eddy currents, a wafer stage with an eddy current suppression design has been developed. For example, a non-conductive plate with a conductive coating can be used as the wafer holder of the wafer stage. However, such alternative designs are generally costly to manufacture and require frequent maintenance. In addition, a wafer holder including a conductive material coating can exacerbate the arc effect when performing high-voltage detection of the wafer.

[0025] Embodiments of the present disclosure can provide beam position displacement compensation or correction techniques for SEM detection. According to some embodiments of the present disclosure, the eddy current effect can be canceled. According to some embodiments of the present disclosure, a wafer stage with conductors can still be utilized while suppressing or minimizing the eddy current effect. According to some embodiments of the present disclosure, the beam position displacement from the target position can be corrected. According to some embodiments of the present disclosure, the effect of the interfering magnetic field can be canceled. Embodiments of the present disclosure can provide a beam position displacement compensation or correction method or system based on the linear relationship between the moving speed of the conductor and the eddy current density induced in the conductor.

[0026] For clarity, the relative sizes of components in the drawings may be exaggerated. In the following description of the drawings, the same or similar reference numerals refer to the same or similar components or entities, and only the differences regarding individual embodiments are described. As used herein, unless otherwise specifically stated, the term "or" encompasses all possible combinations, unless infeasible. For example, if it is stated that a component can include A or B, then unless otherwise specifically stated or infeasible, the component can include A, or B, or A and B. As a second example, if it is stated that a component can include A, B, or C, then unless otherwise specifically stated or infeasible, the component can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0027] FIG. 1 illustrates an example electron beam inspection (EBI) system 100 consistent with an embodiment of the 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, a beam tool 104, and an equipment front end module (EFEM) 106. The 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 a front opening unified pod (FOUP) containing a wafer to be inspected (e.g., a semiconductor wafer or a wafer made of other materials) or a sample to be inspected (the wafer and the sample can be used interchangeably). A "lot" is a plurality of wafers that can be loaded and processed as a batch.

[0028] One or more robotic arms (not shown) in the EFEM 106 can transport the wafer to the load / lock chamber 102. The load / lock chamber 102 is connected to a load / lock vacuum pump system (not shown) that removes gas molecules in the load / lock chamber 102 to reach a first pressure lower than atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) can transport the wafer from the load / lock chamber 102 to the main chamber 101. The main chamber 101 is connected to a main chamber vacuum pump system (not shown) that removes gas molecules in the main chamber 101 to reach a second pressure lower than the first pressure. After reaching the second pressure, the wafer is subjected to inspection by the beam tool 104. The beam tool 104 can be a single beam system or a multi-beam system.

[0029] A controller 109 is electronically connected to the beam tool 104. The controller 109 can be a computer configured to perform various controls on the EBI system 100. Although the controller 109 is shown in FIG. 1 as being external to the structure including the main chamber 101, the load / lock chamber 102, and the EFEM 106, it should be understood that the controller 109 can be part of the structure.

[0030] In some embodiments, the controller 109 may include one or more processors (not shown). The processor may be a general-purpose or specific electronic device capable of manipulating or processing information. For example, the processor may include any number of central processing units (or "CPUs"), graphics processing units (or "GPUs"), optical processors, programmable logic controllers, microcontrollers, microprocessors, digital signal processors, intellectual property (IP) cores, programmable logic arrays (PLAs), programmable array logics (PALs), generic array logics (GALs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), system-on-a-chip (SoCs), application-specific integrated circuits (ASICs), and any combination of any 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.

[0031] In some embodiments, the controller 109 may further include one or more memories (not shown). The memory may be a general-purpose or specific electronic device capable of storing code and data accessible by the processor (e.g., via a bus). For example, the memory may include any number of random access memories (RAMs), read-only memories (ROMs), optical discs, magnetic disks, hard disk drives, solid-state drives, flash drives, secure digital (SD) cards, memory sticks, compact flash (CF) cards, or any combination of any type of storage device. The code and data may include an operating system (OS) and one or more application programs (or "apps") for specific tasks. The memory may also be a virtual memory that includes one or more memories distributed across multiple machines or devices coupled via a network.

[0032] FIG. 2 illustrates a schematic diagram of an exemplary multi-beam tool 104 (also referred to herein as device 104) consistent with embodiments of the present disclosure and an image processing system 290 that can be configured for use in the EBI system 100 (FIG. 1).

[0033] The beam tool 104 includes a charged particle source 202, a gun aperture 204, a condenser lens 206, a primary charged particle beam 210 emitted from the charged particle source 202, a source conversion unit 212, a plurality of thin beams 214, 216, and 218 of the primary charged particle beam 210, a primary projection optical system 220, a motorized wafer stage 280, a wafer holder 282, a plurality of secondary charged particle beams 236, 238, and 240, a secondary optical system 242, and a charged particle detection device 244. The primary projection optical system 220 may include a beam splitter 222, a deflection scanning unit 226, and an objective lens 228. The charged particle detection device 244 may include detection sub-regions 246, 248, and 250.

[0034] The charged particle source 202, the gun aperture 204, the condenser lens 206, the source conversion unit 212, the beam splitter 222, the deflection scanning unit 226, and the objective lens 228 may be aligned with the main optical axis 260 of the apparatus 104. The secondary optical system 242 and the charged particle detection device 244 may be aligned with the sub-optical axis 252 of the apparatus 104.

[0035] The charged particle source 202 may emit one or more charged particles, such as electrons, protons, ions, muons, or any other particle carrying a charge. In some embodiments, the charged particle source 202 may be an electron source. For example, the charged particle source 202 may include a cathode, an extractor, or an anode, where primary electrons may be emitted from the cathode and extracted or accelerated to form a primary charged particle beam 210 (in this case, a primary electron beam) having a crossover point (virtual or real) 208. For ease of explanation without causing divergence, electrons are used as examples in some of the descriptions herein. However, it should be noted that any charged particle may be used in any embodiment of the present disclosure, not limited to electrons. The primary charged particle beam 210 may be visualized as being emitted from the crossover point 208. The gun aperture 204 may block the peripheral charged particles of the primary charged particle beam 210 to reduce the Coulomb effect. The Coulomb effect may cause an increase in the size of the detection light spot.

[0036] The source conversion unit 212 may include an image forming element array and a beam limiting aperture array. The image forming element array may include a microdeflector or a microlens array. The image forming element array may form a plurality of parallel images (virtual or real) of the crossover points 208 with a plurality of thin beams 214, 216, and 218 of the primary charged particle beam 210. The array of beam limiting apertures may limit the plurality of thin beams 214, 216, and 218. Although three thin beams 214, 216, and 218 are shown in FIG. 2, embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the apparatus 104 may be configured to generate a first number of thin beams. In some embodiments, the first number of thin beams may range from 1 to 1000. In some embodiments, the first number of thin beams may range from 200 to 500. In an exemplary embodiment, the apparatus 104 may generate 400 thin beams.

[0037] The condenser lens 206 may focus the primary charged particle beam 210. The current of the thin beams 214, 216, and 218 downstream of the source conversion unit 212 may be changed by adjusting the focusing magnification of the condenser lens 206 or by changing the radial size of the corresponding beam limiting aperture in the beam limiting aperture array. The objective lens 228 may focus the thin beams 214, 216, and 218 onto the wafer 230 for imaging, and may form a plurality of detection light spots 270, 272, and 274 on the surface of the wafer 230.

[0038] The beam splitter 222 may be a beam splitter of the Wien filter type that generates an electrostatic dipole field and a magnetic dipole field. In some embodiments, if an electrostatic dipole field and a magnetic dipole field are applied, the force exerted on the charged particles (e.g., electrons) of the thin beams 214, 216, and 218 by the electrostatic dipole field may be substantially equal in magnitude and opposite in direction to the force exerted on the charged particles by the magnetic dipole field. The thin beams 214, 216, and 218 may thus pass directly through the beam splitter 222 at a zero deflection angle. However, the total dispersion of the thin beams 214, 216, and 218 generated by the beam splitter 222 may be non-zero. The beam splitter 222 may separate the secondary charged particle beams 236, 238, and 240 from the thin beams 214, 216, and 218, and direct the secondary charged particle beams 236, 238, and 240 to the secondary optical system 242.

[0039] The deflection scanning unit 226 can deflect the fine beams 214, 216, and 218 to scan the detection spots 270, 272, and 274 over the surface area of the wafer 230. In response to the incidence of the fine beams 214, 216, and 218 at the detection spots 270, 272, and 274, secondary charged particle beams 236, 238, and 240 can be emitted from the wafer 230. The secondary charged particle beams 236, 238, and 240 can include charged particles (e.g., electrons) having an energy distribution. For example, the secondary charged particle beams 236, 238, and 240 can be secondary electrons including secondary electrons (energy ≤ 50 eV) and backscattered electrons (energy between 50 eV and the landing energy of the fine beams 214, 216, and 218). The secondary optical system 242 can focus the secondary charged particle beams 236, 238, and 240 onto the detection sub-regions 246, 248, and 250 of the charged particle detection device 244. The detection sub-regions 246, 248, and 250 can be configured to detect the corresponding secondary charged particle beams 236, 238, and 240 and generate corresponding signals (e.g., voltage, current, or the like) for reconstructing an SCPM image of the structure above or below the surface area of the wafer 230.

[0040] The generated signals can represent the intensities of the secondary charged particle beams 236, 238, and 240, and the generated signals can be provided to the image processing system 290 that communicates with the charged particle detection device 244, the primary projection optical system 220, and the motorized wafer stage 280. The moving rate of the motorized wafer stage 280 can be synchronized and coordinated with the beam deflection controlled by the deflection scanning unit 226 such that the movement of the scanning detection spots (e.g., scanning detection spots 270, 272, and 274) can orderly cover the regions of interest on the wafer 230. The parameters of this synchronization and coordination can be adjusted to accommodate different materials of the wafer 230. For example, wafers 230 of different materials can have different resistance-capacitance characteristics, which can cause different signal sensitivities to the movement of the scanning detection spots.

[0041] The intensities of the secondary charged particle beams 236, 238, and 240 can vary according to the external or internal structure of the wafer 230 and can thereby indicate whether the wafer 230 includes defects. In addition, as discussed above, the fine beams 214, 216, and 218 can be projected onto different positions on the top surface of the wafer 230 or different sides of the local structure of the wafer 230 to generate secondary charged particle beams 236, 238, and 240 that can have different intensities. Therefore, by mapping the intensities of the secondary charged particle beams 236, 238, and 240 over the regions of the wafer 230, the image processing system 290 can reconstruct an image reflecting the characteristics of the internal or external structure of the wafer 230.

[0042] In some embodiments, the image processing system 290 may include an image acquirer 292, a storage 294, and a controller 296. The image acquirer 292 may include one or more processors. For example, the image acquirer 292 may include a computer, a server, a mainframe computer, a terminal, a personal computer, any kind of mobile computing device or the like, or a combination thereof. The image acquirer 292 may be communicatively coupled to the charged particle detection device 244 of the beam tool 104 via a medium such as a conductor, an optical fiber cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, radio, or a combination thereof. In some embodiments, the image acquirer 292 may receive signals from the charged particle detection device 244 and may construct an image. The image acquirer 292 may thus acquire the SCPM image of the wafer 230. The image acquirer 292 may also perform various post-processing functions, such as generating contours, superimposing indicators on the acquired image, or the like. The image acquirer 292 may be configured to adjust the brightness and contrast of the acquired image. In some embodiments, the storage 294 may be a storage medium such as a hard disk, a flash drive, cloud storage, random access memory (RAM), other types of computer-readable memory, or the like. The storage 294 may be coupled to the image acquirer 292 and may be used to store the scanned raw image data as the raw image and the post-processed image. The image acquirer 292 and the storage 294 may be connected to the controller 296. In some embodiments, the image acquirer 292, the storage 294, and the controller 296 may be integrated together as one control unit.

[0043] In some embodiments, the image acquirer 292 may acquire one or more SCPM images of the wafer based on the imaging signals received from the charged particle detection device 244. The imaging signals may correspond to a scanning operation for performing charged particle imaging. The acquired image may be a single image including a plurality of imaging regions. The single image may be stored in the storage 294. The single image may be a raw image that can be divided into a plurality of regions. Each of the regions may include one imaging region containing features of the wafer 230. The acquired image may include a plurality of images of a single imaging region of the wafer 230 sampled multiple times in a time sequence. The plurality of images may be stored in the storage 294. In some embodiments, the image processing system 290 may be configured to perform image processing steps on the plurality of images of the same position of the wafer 230.

[0044] In some embodiments, the image processing system 290 may include measurement circuitry (e.g., an analog-to-digital converter) to obtain the distribution of detected secondary charged particles (e.g., secondary electrons). The charged particle distribution data collected during the detection time window, combined with the corresponding scan path data of the fine light beams 214, 216, and 218 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 wafer 230 and, thereby, can be used to reveal any defects that may be present in the wafer.

[0045] In some embodiments, the charged particles may be electrons. When the electrons of the primary charged particle beam 210 are projected onto the surface of the wafer 230 (e.g., the probe spots 270, 272, and 274), the electrons of the primary charged particle beam 210 can penetrate the surface of the wafer 230 to a certain depth, thereby interacting with the particles of the wafer 230. Some of the electrons of the primary charged particle beam 210 may interact elastically with the material of the wafer 230 (e.g., in the form of elastic scattering or collisions) and may be reflected or recoiled out of the surface of the wafer 230. Elastic interactions conserve the total kinetic energy of the interacting body (e.g., the electrons of the primary charged particle beam 210), where the kinetic energy of the interacting body is not converted into other forms of energy (e.g., thermal energy, electromagnetic energy, or the like). Such reflected electrons generated from elastic interactions may be referred to as backscattered electrons (BSEs). Some of the electrons in the primary charged particle beam 210 may interact inelastically with the material of the wafer 230 (e.g., in the form of inelastic scattering or collisions). Inelastic interactions do not conserve the total kinetic energy of the interacting body, where some or all of the kinetic energy of the interacting body is converted into other forms of energy. For example, via inelastic interactions, the kinetic energy of some of the electrons in the primary charged particle beam 210 can cause electron excitation and transitions of the atoms of the material. Such inelastic interactions may also generate electrons that are ejected from the surface of the wafer 230, which may be referred to as secondary electrons (SEs). The yield or emission rate of BSEs and SEs depends on, for example, the material under inspection and the landing energy of the electrons of the primary charged particle beam 210 on the surface of the material. The energy of the electrons of the primary charged particle beam 210 can be imparted in part by its acceleration voltage (e.g., the acceleration voltage between the anode and cathode of the charged particle source 202 in FIG. 2). The number of BSEs and SEs can be more or less (or even the same) than the injected electrons of the primary charged particle beam 210.

[0046] The images generated by SEM can be used for defect detection. For example, the images generated by the test device area of the captured wafer can be compared with the reference images of the same test device area. The reference images can be predetermined (e.g., by simulation) and do not include known defects. If the difference between the generated images and the reference images exceeds the tolerance level, potential defects can be identified. For another example, the SEM can scan multiple areas of the wafer, each area including a test device area designed to be the same, and generate multiple images of the captured test device areas manufactured. The multiple images can be compared with each other. If the difference between the multiple images exceeds the tolerance level, potential defects can be identified.

[0047] Figure 3 illustrates a magnetic field generation system of a detection device consistent with an embodiment of the present disclosure. The magnetic field generation system 300 of Figure 3 can be a part of the EBI system 100 of Figure 1 or the electron beam tool 104 of Figure 2. In some embodiments, the magnetic field generation system 300 can generate the system magnetic field of the EBI system 100 of Figure 1 or the electron beam tool 104 during operation. As shown in Figure 3, the magnetic field generation system 300 can include an objective lens (e.g., the objective lens 228 of Figure 2), and the objective lens 228 can include pole pieces 228a, excitation coils 228b, and control electrodes 228c. In some embodiments, the objective lens 228 can be a modified SORIL lens. During the detection or imaging process, a light beam (e.g., the thin light beam 216) can be focused by the objective lens 228 into a detection light spot (e.g., the detection light spot 272) and impinge on the surface of the wafer 230. As discussed, the detection light spot 272 can be scanned across the surface of the wafer 230 by a deflection scanning unit, such as the deflection scanning unit 226 or other deflectors in the SORIL lens. Although Figure 3 illustrates only one light beam 216, it should be understood that multiple light beams can scan the surface of the wafer 230 as shown in Figure 2 simultaneously.

[0048] In some embodiments, the magnetic field generation system 300 including the objective lens 228 can be configured to generate a magnetic field around or within the beam tool 104 during operation. Figure 4A illustrates a static magnetic field generated by the magnetic field generation system 300 of Figure 3 consistent with some embodiments of the present disclosure. As shown in Figure 4A, at least a portion of the motorized stage 280 and the wafer holder 282 can be positioned in the magnetic field of the beam tool. In the present disclosure, the motorized stage 280 and the wafer holder 282 can be collectively referred to as the wafer stage.

[0049] When a conductor moves in a magnetic field, eddy currents can be induced in the conductor according to Faraday's law of induction. The eddy currents flow in a closed loop within the conductor. In some embodiments where the conductor is included in a wafer stage, eddy currents can be induced in the conductor during the operation of the beam tool when the motorized stage 280 moves for wafer scanning. In some embodiments, the wafer stage can be implemented to include a conductor. For example, the wafer chuck 282 can be made of a conductive material such as aluminum, titanium, etc. When the wafer chuck 282 is a conductor, eddy currents can be induced in the wafer chuck 282 when the wafer chuck 282 moves in the magnetic field generated by the magnetic field generation system 300 of the beam tool.

[0050] Figure 4B illustrates eddy currents in a conductor generated by the movement of a wafer stage in accordance with an embodiment of the present disclosure. In Figure 4B, for illustrative purposes, it is assumed that the wafer chuck 282 is a conductor. In Figure 4B, the current density J A / m2 is defined by the contrast bar at the bottom. In this example, the first current density J1 is lower than the second current density J2, and the second current density J2 is in turn lower than the third current density J3. In Figure 4B, when the wafer chuck 282 made of titanium moves at a rate of 400 mm / s, the eddy current density induced in the wafer chuck 282 is indicated in the wafer chuck 282. As shown in Figure 4B, the eddy current density is non-uniform across the wafer chuck 282. For example, the eddy current density can vary depending on the position on the wafer chuck 282.

[0051] Furthermore, the induced eddy currents in the wafer chuck 282 can generate a magnetic field that interferes with the magnetic field of the beam tool generated by the magnetic field generation system 300. Figure 4C illustrates the interference magnetic field caused by the eddy currents in the conductor in accordance with an embodiment of the present disclosure. In Figure 4C, the X-axis indicates the distance from the left end to the right end of the wafer (e.g., wafer 230) held by the free wafer chuck 282, and the Y-axis indicates the magnitude of the interference magnetic field on the wafer caused by the eddy currents in the wafer chuck 282. As shown in Figure 4C, the interference magnetic field caused by the eddy currents in the moving wafer chuck 282 affects the points of interest on the wafer and thus interferes with the system magnetic field of the beam tool, such as the system magnetic field generated by the magnetic field generation system 300.

[0052] However, detection equipment (e.g., the EBI system 100 or the electron beam tool 104 of FIG. 1) is vulnerable to such magnetic field interference. For example, such interfering magnetic fields can cause beam displacement at the position of the target beam on the wafer during wafer scanning, which in turn leads to deterioration of image quality. To avoid inducing eddy currents, a wafer stage with an eddy current suppression design has been utilized. The eddy current suppression design can include a non-conductive wafer holder instead of a conductive wafer holder. In this case, a non-conductive plate can be coated with a conductive material to be used as a wafer holder, for example, for surface charge suppression. For example, a chromium-coated ceramic is used as a wafer holder. However, due to the materials used for the coating (e.g., chromium) or non-conductive materials (e.g., ceramics), such alternative designs are generally costly to manufacture. In addition, such coatings require frequent maintenance.

[0053] In addition to cost and cumbersome reasons, using a non-conductive plate coated with a conductive material as a wafer holder can exacerbate the arc problem during high-voltage detection of the wafer. When detecting the wafer with high voltage, arcs can occur on the conductive coating, and the arcs can cause particles of the coating to separate. The particles left from the coating can contaminate the detection and the wafer, and thereby worsen the arc effect. Embodiments of the present disclosure can provide a method or system for canceling the eddy current effect when using a wafer stage including a conductor, such as a conductor wafer holder.

[0054] FIG. 5 is a block diagram of a beam displacement compensation system consistent with embodiments of the present disclosure. In some embodiments, the beam displacement compensation system 500 includes one or more processors and a memory. It should be understood that in various embodiments, the beam displacement compensation system 500 can be part of a charged particle beam detection system (e.g., the EBI system 100 of FIG. 1) or can be separate from the charged particle beam detection system. In some embodiments, the beam displacement compensation system 500 can include one or more components (e.g., software modules) that can be implemented in a controller 109 or a system 290 as discussed herein. As shown in FIG. 5, the beam displacement compensation system 500 can include a first beam position acquirer 510, a second beam position acquirer 520, a beam displacement calculator 530, and a beam displacement calibrator 540.

[0055] According to some embodiments of the present disclosure, when the wafer stage supporting the test wafer moves at a first speed, the first beam position acquirer 510 can acquire the position of the first beam on the test wafer. In some embodiments, the position of the first beam on the test wafer can be measured from the acquired first detection image when the wafer stage moves at the first speed V1. Although the speed in the present disclosure can represent both the speed of the wafer stage movement and the direction of the wafer stage movement, it should be understood that in some embodiments, the speed can also be used to refer to the rate. In some embodiments, the detection image is an SEM image of a sample or a wafer. In some embodiments, the detection image can be a detection image generated by, for example, the EBI system 100 of FIG. 1 or the electron beam tool 104 of FIG. 2. In some embodiments, the detection image can be obtained from a storage device or system storing the detection image.

[0056] According to some embodiments of the present disclosure, when the wafer stage is stationary, that is, the first speed V1 is zero, the first detection image can be acquired. In some embodiments, the first detection image can be acquired when there is no interference magnetic field, such as that caused by eddy currents in a moving conductor. FIG. 6A illustrates an example first detection image 610 consistent with some embodiments of the present disclosure. In FIG. 6A, the positions on the test wafer can be represented by x and y coordinates, where the center of the test wafer is represented as (0, 0). FIG. 6A shows a first beam 611 positioned at the center of the first detection image 610, which indicates that the first beam 611 impinges on the test wafer at the center of the test wafer. Although the first beam 611 positioned at the center of the wafer is described, it should be understood that the first beam 611 can be positioned on any part of the wafer.

[0057] In some embodiments, a wafer having known patterns at corresponding positions on the wafer can be used as a test wafer. In some embodiments, the beam positions on the wafer can be determined by matching the pattern of the SEM image obtained by the first beam with the corresponding pattern on the wafer and by identifying the positioning of the corresponding pattern on the wafer. In some embodiments, a reference image of the test wafer can be used to determine the pattern of the test wafer and the corresponding positions of the patterns on the test wafer. In some embodiments, the reference image can be a golden image or a layout file for the wafer design corresponding to the test wafer. The layout file can be in a format such as Graphics Database System (GDS) format, Graphics Database System II (GDS II) format, Open Artwork System Interchange Standard (OASIS) format, California Institute of Technology Intermediate Format (CIF), etc. The wafer design can include patterns or structures to be included on the wafer. The patterns or structures can be mask patterns for transferring features from a photolithography mask or a reticle to the wafer. In some embodiments, a layout in a format such as GDS or OASIS can contain feature information stored in a binary file format that represents planar geometries, text, and other information related to the wafer design. In some embodiments, the reference image can be an image reproduced from the layout file.

[0058] Referring back to FIG. 5, according to some embodiments of the present disclosure, the second beam position acquirer 520 can acquire the second beam position on the test wafer while the wafer stage supporting the test wafer is moving at a second speed. In some embodiments, the second beam position on the test wafer can be measured from the acquired second detection image while the wafer stage is moving at the second speed V2. In some embodiments, the second detection image is an SEM image of a sample or a wafer. In some embodiments, the second detection image can be a detection image generated by, for example, the EBI system 100 of FIG. 1 or the electron beam tool 104 of FIG. 2. In some embodiments, the second detection image can be obtained from a storage device or system storing the second detection image.

[0059] According to some embodiments of the present disclosure, when the wafer stage moves at a second speed different from the first speed, a second detection image can be obtained. In some embodiments, the second speed can be set to the maximum speed of the wafer stage of the beam tool. In some embodiments, when there is an interfering magnetic field caused by, for example, eddy currents in a moving conductor, a second detection image can be obtained. In some embodiments, in addition to the wafer stage moving at a different speed, the second detection image can be obtained under the same detection conditions as the first detection image. In some embodiments, the detection conditions include but are not limited to beam deflection, system magnetic field, operating voltage, beam current, target beam position on the wafer, etc. FIG. 6B illustrates an example second detection image 620 and a second beam 621 consistent with some embodiments of the present disclosure. Assuming that the target beam position of the second beam 621 is the same as that of the first beam 611, that is, in the second detection image 620, the wafer center (0, 0) shown in FIG. 6A is obtained under the same conditions as the first detection image 610 except for the movement of the wafer stage. FIG. 6B shows the second beam 621 located at the position (xd, yd) on the second detection image 620, which is displaced from the target beam position, i.e., the wafer center (0, 0).

[0060] Referring back to FIG. 5, when the wafer stage moves at a third speed within the speed range from the first speed to the second speed, the beam displacement calculator 530 can calculate the beam position displacement of the beam when detecting the wafer. Although some embodiments will be explained by assuming that the first speed is zero, it should be understood that the present disclosure can also be applied to some embodiments in which the first speed is non-zero.

[0061] In some embodiments where the third speed is equal to the second speed, the beam position displacement of the light beam can be equal to the beam position displacement of the second beam relative to the first beam. As shown in FIG. 6C, which illustrates the beam position displacement between the first beam 611 and the second beam 621, the second beam 621 is displaced by a displacement D2 from the first beam 611. In some embodiments, the beam position displacement can be measured in the X-Y plane. As shown in FIG. 6C, the position of the second beam 621 is offset from the position of the first beam 611 by a distance xd in the X direction and a distance yd in the Y direction. In some embodiments, the displacement D2 can represent either the displacement scalar or both the displacement scalar and the direction of the displacement. In some embodiments, the beam position displacement of the second beam relative to the first beam can also be measured in the z direction. In some embodiments, the beam position displacement in the z direction can be measured by the focal point displacement of the second beam from the focal point of the first beam. For example, although the focal point of the first beam can be placed on the surface of the wafer that is the target for detection, the focal point of the second beam can be placed in a plane below or above the wafer surface in the z direction. In some embodiments, the focal point of the beam can be determined based on the degree of blurring of the detection image. In some embodiments, the focal point of the beam can be determined based on the size of the beam spot on the detection image. Although some embodiments will be explained with respect to the position displacement in the X-Y plane, it should be understood that the present disclosure can be applied to some embodiments where the beam position is displaced in the z direction.

[0062] In some embodiments where the third speed is greater than the first speed and less than the second speed, the beam position displacement of the light beam can be calculated based on the beam displacement of the second beam. In some embodiments, the displacement D2 of the second beam 621 can be understood to be caused by the interfering magnetic field due to the eddy current in the moving conductor rather than the speed of the wafer stage when obtaining the first detection image 610 and the second detection image 620 under the detection conditions. Since the eddy current density in the moving conductor has a linear relationship with the speed of the moving conductor, the beam position displacement can be determined based on the speed of the moving conductor. As described with reference to FIG. 4B, since the eddy current density is non-uniform in the moving conductor and thus the interfering magnetic field varies depending on the X-Y position of the wafer, the beam position displacement can be further determined based on the X-Y position of the beam on the wafer.

[0063] FIG. 7 illustrates an example beam displacement table consistent with some embodiments of the present disclosure. In FIG. 7, the displacement table 700 lists positions P1 to Pn on the wafer in the first column. In some embodiments, the positions P1 to Pn on the wafer may be beam positions on the X-Y plane of the wafer. For example, the position (0, 0) of the first beam 611 in the first detection image 610 may be the first position P1. The positions P2 to Pn may be positions on the wafer other than the first position P1. In some embodiments, the positions P1 to Pn may be target positions of the beams on the wafer. Although obtaining the beam position displacement of the second beam 621 from the first beam 611 targeting one position (e.g., the first position P1) has been illustrated, it should be understood that the present disclosure can also be used to obtain multiple beam position displacements of the second beam 621 from the first beam 611 targeting multiple positions (e.g., positions P2 to Pn) on the wafer.

[0064] In FIG. 7, the displacement table 700 further lists the speed V2 in the first row. In some embodiments, the speed V2 in FIG. 7 may be the maximum speed of the wafer stage of the beam tool. In FIG. 7, the displacement values D21 to D2n in the second column may be the beam position displacements of the second beam relative to the first beam. For example, the beam position displacement of the second beam 621 and the first beam 611 (e.g., the distance xd in the X direction and the distance yd in the Y direction) may be the first displacement D21. Similarly, the beam position displacements of the second beam relative to the corresponding first beams at different positions P2 to Pn on the wafer may be the beam position displacements D22 to D2n.

[0065] In some embodiments where the third speed is greater than the first speed and less than the second speed, the beam position displacement of the beam can be calculated based on the beam position on the wafer and the first to third speeds. In some embodiments, the beam position displacement of the beam can be calculated based on the beam displacement table 700. As described, the eddy current generated in the conductor is proportional to the speed of the conductor, and thus the beam displacement caused by the eddy current also has a linear relationship with the speed. In some embodiments, when the wafer stage moves at the third speed V3, the beam position displacement of the beam for detecting the wafer can be calculated by the ratio of the third speed V3 to the second speed V2. For example, when the wafer stage moves at the third speed V3, the beam position displacement D31 of the third beam targeted at the first position P1 can be determined by multiplying the first beam displacement of the second beam 621 targeted at the first position P1 by the ratio V3 / V2, i.e., D31 = D21 * V3 / V2. Similarly, the beam position displacements D32 to D3n of the third beam targeted at the positions P2 to Pn can be determined based on the ratio V3 / V2 and the corresponding beam displacements D22 to D2n of the second beam.

[0066] Referring back to FIG. 5, the beam displacement calibrator 540 can adjust the beam position on the wafer for detecting the wafer when the wafer stage moves at the third speed. In some embodiments, the beam displacement calibrator 540 can adjust the beam position based on the beam displacement of the beam determined by the beam displacement calculator 530.

[0067] In some embodiments, the beam displacement calibrator 540 can adjust the beam position to cancel out the beam position displacement of the beam. In some embodiments, the beam displacement calibrator 540 can generate a control signal to cancel out the beam position displacement of the beam. For example, the beam displacement calibrator 540 can generate a control signal to adjust the operating parameters of the deflection scanning unit, such as the deflection scanning unit 226 in FIG. 2. In some embodiments, the control signal for canceling out the beam displacement can be sent to the driver of the deflection scanning unit. In some embodiments where the beam position is displaced in the Z direction, the beam displacement calibrator 540 can generate a control signal for canceling out the beam position displacement in the Z direction. For example, the beam displacement calibrator 540 can generate a control signal to adjust the height of the wafer and send the control signal to the wafer stage controller.

[0068] According to some embodiments, the beam displacement of a light beam can be caused by an interfering magnetic field, for example, an interfering magnetic field induced by the wafer stage moving at a third speed. In some embodiments, the beam displacement calibrator 540 can adjust the system magnetic field of the beam tool 104 to cancel out the interfering magnetic field. For example, the beam displacement calibrator 540 can generate a control signal to adjust the operating parameters of the objective lens, such as the objective lens 228 in FIGS. 2 and 3, to eliminate or minimize the interfering magnetic field. In some embodiments, a control signal for canceling out the effect of the interfering magnetic field can be sent to the driver of the objective lens.

[0069] In some embodiments, the beam displacement calibrator 540 can generate a control signal to adjust the operating parameters of any component of the detection device (e.g., the EBI system 100 in FIG. 1 or the electron beam tool 104 in FIG. 2) to compensate for the beam displacement of the light beam or cancel out the interfering magnetic field. For example, the beam displacement calibrator 540 can generate a control signal to adjust the operating voltage, beam current, magnetic field generating current, etc. In some embodiments, the beam displacement calibrator 540 can generate a control signal to adjust the operating parameters of an external device other than the detection device (e.g., the EBI system 100 in FIG. 1 or the electron beam tool 104 in FIG. 2) to compensate for the beam displacement of the light beam or cancel out the interfering magnetic field. For example, the external device can be used to eliminate the interfering magnetic field or cancel out the beam displacement.

[0070] FIG. 8 is a process flowchart showing an exemplary beam displacement compensation method consistent with an embodiment of the present disclosure. The steps of method 800 can be performed by a system (e.g., system 500 in FIG. 5) executing on an arithmetic device (e.g., controller 109 in FIG. 1) or otherwise using its features. It should be understood that the illustrated method 800 can be modified to change the order of steps and include additional steps.

[0071] In step S810, a first beam position can be obtained. Step S810 can be performed by, for example, the first beam position acquirer 510 and others. According to some embodiments of the present disclosure, the first beam position on the test wafer can be obtained while the wafer stage supporting the test wafer is moving at a first speed. In some embodiments, the first beam position on the test wafer can be measured from the acquired first detection image while the wafer stage is moving at a first speed V1. In some embodiments, when the wafer stage is stationary, i.e., the first speed V1 is zero, the first detection image can be obtained.

[0072] In step S820, the position of the second light beam can be obtained. Step S820 can be performed by, for example, the second light beam position acquirer 520 and others. According to some embodiments of the present disclosure, when the wafer stage supporting the test wafer moves at a second speed, the position of the second light beam on the test wafer can be obtained. In some embodiments, the position of the second light beam on the test wafer can be measured from the acquired second detection image when the wafer stage moves at the second speed V2. According to some embodiments of the present disclosure, when the wafer stage moves at a second speed different from the first speed, a second detection image can be obtained. In some embodiments, the second speed can be set to the maximum speed of the wafer stage of the beam tool. In some embodiments, when there is an interference magnetic field caused by, for example, eddy currents in the moving conductor, a second detection image can be obtained. In some embodiments, in addition to the wafer stage moving at different speeds, the second detection image can be obtained under the same detection conditions as the first detection image. In some embodiments, the target position of the second light beam is the same as that of the first light beam.

[0073] In step S830, the displacement of the light beam position of the light beam can be calculated. Step S830 can be performed by, for example, the beam displacement calculator 530 and others. According to some embodiments of the present disclosure, when the wafer stage moves at a third speed, the displacement of the light beam position of the light beam when detecting the wafer can be calculated. In some embodiments, the third speed is within the speed range from the first speed to the second speed.

[0074] In some embodiments where the third speed is equal to the second speed, the displacement of the light beam position of the light beam can be equal to the displacement of the light beam position of the second light beam relative to the first light beam. In some embodiments where the third speed is greater than the first speed and less than the second speed, the displacement of the light beam position of the light beam can be calculated based on the light beam displacement of the second light beam. Since the eddy current density in the moving conductor has a linear relationship with the speed of the moving conductor, the displacement of the light beam position can be determined based on the speed of the moving conductor. As described with reference to FIG. 4B, since the eddy current density is non-uniform in the moving conductor and thus the interference magnetic field varies depending on the X-Y position of the wafer, the displacement of the light beam position can be further determined based on the X-Y position of the light beam on the wafer. The process of calculating the displacement of the light beam position has been described with reference to FIGS. 6C and 7, and thus for the sake of simplicity, detailed explanations will be omitted.

[0075] In step S840, the beam position of the adjustable beam can be adjusted. Step S840 can be performed by, for example, the beam displacement calibrator 540 and others. According to some embodiments, when the wafer stage moves at a third speed, the beam position on the wafer can be adjusted for wafer detection. In some embodiments, the beam position can be adjusted based on the beam displacement of the beam determined at step S830. In some embodiments, the beam position can be adjusted to cancel the beam position displacement of the beam. In some embodiments, a control signal can be generated to cancel the beam position displacement of the beam. In some embodiments, the system magnetic field of the beam tool 104 can be adjusted to cancel the interference magnetic field. In some embodiments, a control signal can be generated to adjust the operating parameters of any component of the detection device (e.g., the EBI system 100 of FIG. 1 or the electron beam tool 104 of FIG. 2) to compensate for the beam displacement of the beam or cancel the interference magnetic field. In some embodiments, a control signal can be generated to adjust the operating parameters of external devices other than the detection device (e.g., the EBI system 100 of FIG. 1 or the electron beam tool 104 of FIG. 2) to compensate for the beam displacement of the beam or cancel the interference magnetic field.

[0076] A non-transitory computer-readable medium can be provided that stores instructions for a processor of a controller (e.g., the controller 109 of FIG. 1) to perform, among other things: image detection, image acquisition, stage positioning, beam focusing, electric field adjustment, beam bending, condenser lens adjustment, starting a charged particle source, beam deflection, and method 800. Common forms of non-transitory media include, for example, floppy disks, flexible disks, hard disks, solid state hard disks, magnetic tapes, or any other magnetic data storage media, compact disc read-only memory (CD-ROM), any other optical data storage media, any physical media with a hole pattern, random access memory (RAM), programmable read-only memory (PROM), and erasable programmable read-only memory (EPROM), FLASH-EPROM, or any other flash memory, non-volatile random access memory (NVRAM), cache memory, registers, any other memory chip or cartridge, and their networked versions.

[0077] The embodiments can be further described using the following items: 1. A method for correcting detection image errors, comprising: acquiring a first set of beam positions on the test wafer when a wafer stage supporting a test wafer moves at a first speed; acquiring a second set of beam positions on the test wafer corresponding to the first set of beam positions when the wafer stage moves at a second speed; When the wafer stage moves at a third speed within a speed range from the first speed to the second speed, calculating a beam position displacement of a beam; and Adjusting a beam position of the beam based on the calculated beam position displacement. 2. The method according to item 1, wherein the first speed is zero. 3. The method according to item 1 or 2, wherein adjusting the beam position includes: Generating a control signal to adjust an operating parameter of a beam deflector. 4. The method according to item 1 or 2, wherein adjusting the beam position includes: Generating a control signal to adjust a magnetic field of a beam detection tool during operation. 5. The method according to any one of items 1 to 4, wherein adjusting the beam position includes: Adjusting the beam position based on a target position of the beam on a wafer, the first beam position and the second beam position, the first speed and the second speed and the third speed. 6. The method according to any one of items 1 to 5, wherein adjusting the beam position includes: Adjusting the beam position by offsetting the calculated beam position displacement. 7. The method according to any one of items 1 to 6, wherein the beam position displacement is calculated based on a target position of the beam on a wafer, a first beam position among a set of first beam positions corresponding to the target position and a second beam position among a set of second beam positions corresponding to the target position, the first speed and the second speed and the third speed. 8. The method according to any one of items 1 to 7, wherein adjusting the beam position includes: Adjusting the beam position by offsetting a magnetic field interference caused by the movement of the wafer stage at the third speed. 9. The method according to any one of items 1 to 8, further comprising: Detecting a wafer based on the adjusted beam position on the wafer when the wafer stage moves at the third speed. 10. The method according to any one of items 1 to 9, wherein the wafer stage includes a conductor. 11. A method for correcting a detection image error, comprising: Obtaining a first beam position on a test wafer when a wafer stage supporting the test wafer is stationary; When the wafer stage moves at a first speed, a second beam position on the test wafer is acquired, and the second beam positions correspond to the first beam positions; Determine a displacement of the second beam positions from the positions corresponding to the first beam positions; and Based on a target position of one of the beams on the wafer, a corresponding position displacement among the determined position displacements, and the first speed, adjust a beam position of a beam for detecting a wafer. 12. The method according to item 11, wherein the position displacements of the second beam positions include a first position displacement and a second position displacement, and the first position displacement is different from the second position displacement. 13. The method according to item 11 or 12, further comprising: Determine a beam displacement of one of the beams when the wafer stage moves at a second speed different from the first speed. 14. The method according to item 13, wherein determining the beam displacement of the beam includes: Determine the beam displacement of the beam based on the corresponding position displacement and a ratio of the second speed to the first speed. 15. The method according to item 14, wherein adjusting the beam position includes: Adjust the beam position based on the beam displacement of the beam. 16. The method according to any one of items 11 to 15, wherein adjusting the beam position includes: Generate a control signal to adjust an operating parameter of a beam deflector. 17. The method according to any one of items 11 to 16, wherein adjusting the beam position includes: Generate a control signal to adjust a magnetic field of a beam detection tool during operation. 18. The method according to any one of items 13 to 15, wherein adjusting the beam position includes: Adjust the beam position by offsetting the determined beam displacement. 19. The method according to any one of items 13 to 15, wherein adjusting the beam position includes: Adjust the beam position by offsetting a magnetic field interference caused by the movement of the wafer stage at the second speed. 20. The method according to any one of items 11 to 19, further comprising: When the wafer stage moves at the second speed, detect the wafer based on the adjusted beam position on the wafer. 21. An apparatus for correcting a detection image error, comprising: A memory that stores an instruction set; and At least one processor configured to execute the instruction set to cause the device to perform the following operations: When moving a wafer stage supporting a test wafer at a first speed, obtaining a first set of beam positions on the test wafer; When the wafer stage moves at a second speed, obtaining a second set of beam positions on the test wafer corresponding to the first set of beam positions; When the wafer stage moves at a third speed within a speed range from the first speed to the second speed, calculating a beam position displacement of a beam; and Adjusting a beam position of the beam based on the calculated beam position displacement. 22. The device according to item 21, wherein the first speed is zero. 23. The device according to item 21 or 22, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the device to perform the following operations: Generating a control signal to adjust an operating parameter of a beam deflector. 24. The device according to item 21 or 22, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the device to perform the following operations: Generating a control signal to adjust a magnetic field of a beam detection tool during operation. 25. The device according to any one of items 21 to 24, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the device to perform the following operations: Adjusting the beam position based on a target position of the beam on a wafer, the first beam position and the second beam position, the first speed and the second speed and the third speed. 26. The device according to any one of items 21 to 25, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the device to perform the following operations: Adjusting the beam position by offsetting the calculated beam position displacement. 27. The device according to any one of items 21 to 26, wherein the beam position displacement is calculated based on a target position of the beam on a wafer, a first beam position among the first set of beam positions corresponding to the target position, and a second beam position among the second set of beam positions corresponding to the target position, the first speed and the second speed and the third speed. 28. The apparatus according to any one of clauses 21 to 27, wherein when adjusting the position of the beam, the at least one processor is configured to execute the instruction set to cause the apparatus to perform the following operations: Adjust the position of the beam by offsetting a magnetic field interference caused by the movement of the wafer stage at the third speed. 29. The apparatus according to any one of clauses 21 to 28, wherein the at least one processor is configured to execute the instruction set to cause the apparatus to further perform the following operations: Detect a wafer based on the adjusted beam position on the wafer when the wafer stage moves at the third speed. 30. The apparatus according to any one of clauses 21 to 29, wherein the wafer stage includes a conductor. 31. An apparatus for correcting detection image errors, comprising: A memory that stores an instruction set; and At least one processor configured to execute the instruction set to cause the apparatus to perform the following operations: Obtain a first beam position on a test wafer when a wafer stage supporting the test wafer is stationary; Obtain second beam positions on the test wafer when the wafer stage moves at a first speed, the second beam positions corresponding to the first beam positions; Determine a position displacement of the second beam positions from the positions of the corresponding first beam positions; and Adjust a beam position of a beam for detecting a wafer based on a target position of the beam on the wafer, a corresponding position displacement among the determined position displacements, and the first speed. 32. The apparatus according to clause 31, wherein the position displacements of the second beam positions include a first position displacement and a second position displacement, and the first position displacement is different from the second position displacement. 33. The apparatus according to clause 31 or 32, wherein the at least one processor is configured to execute the instruction set to cause the apparatus to further perform the following operations: Determine a beam displacement of the beam when the wafer stage moves at a second speed different from the first speed. 34. The apparatus according to clause 33, wherein when determining the beam displacement of the beam, the at least one processor is configured to execute the instruction set to cause the apparatus to perform the following operations: Determine the beam displacement of the beam based on the corresponding position displacement and a ratio of the second speed to the first speed. 35. The apparatus of clause 34, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the apparatus to perform the following operations: Adjust the beam position based on the beam displacement of the beam. 36. The apparatus of any one of clauses 31 to 35, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the apparatus to perform the following operations: Generate a control signal to adjust an operating parameter of a beam deflector. 37. The apparatus of any one of clauses 31 to 36, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the apparatus to perform the following operations: Generate a control signal to adjust a magnetic field of a beam detection tool during operation. 38. The apparatus of any one of clauses 33 to 35, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the apparatus to perform the following operations: Adjust the beam position by offsetting the determined beam displacement. 39. The apparatus of any one of clauses 33 to 35, wherein when adjusting the beam position, the at least one processor is configured to execute the instruction set to cause the apparatus to perform the following operations: Adjust the beam position by offsetting a magnetic field interference caused by the movement of the wafer stage at the second speed. 40. The apparatus of any one of clauses 31 to 39, wherein the at least one processor is configured to execute the instruction set to cause the apparatus to further perform the following operations: Detect the wafer based on the adjusted beam position on the wafer when the wafer stage moves at the second speed. 41. A non-transitory computer-readable medium storing an instruction set executable by at least one processor of an arithmetic device to cause the arithmetic device to perform a method for correcting a detected image, the method comprising: Acquire a first set of beam positions on a test wafer when a wafer stage supporting the test wafer moves at a first speed; Acquire a second set of beam positions on the test wafer corresponding to the first set of beam positions when the wafer stage moves at a second speed; Calculate a beam position displacement of a beam when the wafer stage moves at a third speed within a speed range from the first speed to the second speed; and Adjust a beam position of the beam based on the calculated beam position displacement. 42. The computer-readable medium as recited in clause 41, wherein the first speed is zero. 43. The computer-readable medium as recited in clause 41 or 42, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Generate a control signal to adjust an operating parameter of a beam deflector. 44. The computer-readable medium as recited in clause 41 or 42, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Generate a control signal to adjust a magnetic field of a beam detection tool during operation. 45. The computer-readable medium as recited in any one of clauses 41 to 44, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Adjust the beam position based on a target position of the beam on a wafer, the first beam position and the second beam position, the first speed and the second speed and the third speed. 46. The computer-readable medium as recited in any one of clauses 41 to 45, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Adjust the beam position by offsetting the calculated beam position displacement. 47. The computer-readable medium as recited in any one of clauses 41 to 46, wherein the beam position displacement is calculated based on a target position of the beam on a wafer, a first beam position among a set of first beam positions corresponding to the target position, and a second beam position among a set of second beam positions corresponding to the target position, the first speed and the second speed and the third speed. 48. The computer-readable medium as recited in any one of clauses 41 to 47, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Adjust the beam position by offsetting a magnetic field interference caused by the movement of the wafer stage at the third speed. 49. The computer-readable medium as recited in any one of clauses 41 to 48, wherein the instruction set executable by at least one processor of the computing device causes the computing device to further perform the following operations: When the wafer stage moves at the third speed, a wafer is detected based on the adjusted beam position on the wafer. 50. A computer-readable medium as in any one of clauses 41 to 49, wherein the wafer stage includes a conductor. 51. A non-transitory computer-readable medium storing a set of instructions that are executed by at least one processor of a computing device to cause the computing device to perform a method for correcting a detected image, the method comprising acquiring a first beam position on a test wafer while a wafer stage supporting the test wafer is stationary; acquiring second beam positions on the test wafer while the wafer stage moves at a first speed, the second beam positions corresponding to the first beam positions; determining a position displacement of the second beam positions from positions corresponding to the first beam positions; and adjusting a beam position of a beam for detecting a wafer based on a target position of the beam on the wafer, a corresponding position displacement among the determined position displacements, and the first speed. 52. The computer-readable medium as in clause 51, wherein the position displacements of the second beam positions include a first position displacement and a second position displacement, and the first position displacement is different from the second position displacement. 53. The computer-readable medium as in clause 51 or 52, wherein the set of instructions is executable by at least one processor of the computing device to cause the computing device to further perform the following operations: determining a beam displacement of the beam while the wafer stage moves at a second speed different from the first speed. 54. The computer-readable medium as in clause 53, wherein when determining the beam displacement of the beam, the set of instructions executable by at least one processor of the computing device causes the computing device to perform the following operations: determining the beam displacement of the beam based on the corresponding position displacement and a ratio of the second speed to the first speed. 55. The computer-readable medium as in clause 54, wherein when adjusting the beam position, the set of instructions executable by at least one processor of the computing device causes the computing device to perform the following operations: adjusting the beam position of the beam based on the beam displacement of the beam. 56. The computer-readable medium as in any one of clauses 51 to 55, wherein when adjusting the beam position, the set of instructions executable by at least one processor of the computing device causes the computing device to perform the following operations: Generate a control signal to adjust an operating parameter of a beam deflector. 57. The computer-readable medium according to any one of clauses 51 to 56, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Generate a control signal to adjust a magnetic field of a beam detection tool during operation. 58. The computer-readable medium according to any one of clauses 53 to 55, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Adjust the beam position by offsetting the determined beam displacement. 59. The computer-readable medium according to any one of clauses 53 to 55, wherein when adjusting the beam position, the instruction set executable by at least one processor of the computing device causes the computing device to perform the following operations: Adjust the beam position by offsetting a magnetic field interference caused by the movement of the wafer stage at the second speed. 60. The computer-readable medium according to any one of clauses 51 to 59, wherein the instruction set executable by at least one processor of the computing device causes the computing device to further perform the following operations: Detect the wafer based on the adjusted beam position on the wafer when the wafer stage moves at the second speed.

[0078] The block diagrams in the figures may illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer hardware or software products according to various exemplary embodiments of the present disclosure. In this regard, each block in the schematic diagram may represent an arithmetic or logical operation process that can be implemented in hardware such as an electronic circuit. The block may also represent a module, section, or part of a program code containing one or more executable instructions for implementing the specified logical function. It should be understood that in some alternative implementations, the functions indicated in the blocks may not occur in the order mentioned in the figures. For example, depending on the functionality involved, two consecutively shown blocks may be executed or implemented substantially simultaneously, or the two blocks may sometimes be executed in the reverse order. Some blocks may also be omitted. It should also be understood that each block of the block diagram and combinations of blocks may be implemented by a system based on dedicated hardware that performs the specified functions or actions, or by a combination of dedicated hardware and computer instructions.

[0079] It should be understood that the embodiments of the present disclosure are not limited to the exact structures described above and illustrated in the accompanying drawings, and various modifications and changes can be made without departing from the scope of the present invention. The present disclosure has been described in connection with various embodiments, and other embodiments of the present invention will be apparent to those of ordinary skill in the art by considering the specifications and practices of the present invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the present invention being indicated by the following claims.

[0080] 100: Electron Beam Inspection (EBI) System 101: Main Chamber 102: Load / Lock Chamber 104: Beam Tool 106: Equipment Front End Module 106a: First Loading Port 106b: Second Loading Port 109: Controller 202: Charged Particle Source 204: Gun Aperture 206: Condensing Lens 208: Crossing Point 210: Primary Charged Particle Beam 212: Source Conversion Unit 214: Thin Beam 216: Thin Beam 218: Thin Beam 220: Primary Projection Optical System 222: Beam Splitter 226: Deflection Scanning Unit 228: Objective Lens 228a: Pole Piece 228b: Excitation Coil 228c: Control Electrode 230: Wafer 236: Secondary Charged Particle Beam 238: Secondary Charged Particle Beam 240: Secondary Charged Particle Beam 242: Secondary Optical System 244: Charged Particle Detection Device 246: Detection Sub-region 248: Detection Sub-region 250: Detection Sub-region 252: Secondary Optical Axis 260: Main Optical Axis 270: Detection light spot 272: Detection light spot 274: Detection light spot 280: Movable wafer stage 282: Wafer holder 290: Image processing system 292: Image acquirer 294: Storage 296: Controller 300: Magnetic field generation system 500: Beam displacement compensation system 510: First beam position acquirer 520: Second beam position acquirer 530: Beam displacement calculator 540: Beam displacement calibrator 610: First detection image 611: First beam 620: Second detection image 621: Second beam 700: Displacement table 800: Method D 2: Displacement D 21: Displacement value D 22: Displacement value D 2n: Displacement value D 31: Beam position displacement D 32: Beam position displacement D 3n: Beam position displacement J1: First current density J2: Second current density J3: Third current density P 1: Position P 2: Position P n: Position V 1: First velocity V 2: Second velocity V 3: Third velocity S810: Step S820: Step S830: Step S840: Step x: Coordinate x d: Distance y d: Distance y: Coordinate (0, 0): Wafer center (x d, y d): Position

Claims

1. A non-transitory computer-readable medium storing an instruction set executable by at least one processor of a computing device to cause the computing device to perform a method for reducing distortions in a SEM system, the method comprising: obtaining a first position on the sample while the wafer stage supporting a sample moves at a first speed; obtaining a beam displacement on the sample corresponding to the first position while the wafer stage moves at a second speed; calculating a beam position displacement of a beam while the wafer stage moves at a third speed within the range of the first speed to the second speed; and adjusting a beam position of the beam based on the calculated beam position displacement.

2. The non-transitory computer-readable medium as requested in item 1, wherein the first speed is zero.

3. The non-transitory computer-readable medium as requested in item 1 or 2, wherein the second speed is one of the maximum speeds of the wafer stage.

4. A non-transitory computer-readable medium as claimed in claim 1 or 2, wherein the beam position displacement is calculated by means of a ratio of the third speed to the second speed when the wafer stage moves at the third speed.

5. A non-transitory computer-readable medium as requested in item 1 or 2, wherein the beam position of the beam is adjusted as the wafer stage moves at the third speed.

6. The non-transitory computer-readable medium as requested in item 1 or 2, wherein adjusting the beam position comprises: generating a control signal to adjust an operating parameter of a beam deflector included in the SEM system.

7. The non-transitory computer-readable medium of claim 1 or 2, wherein adjusting the position of the beam comprises: generating a control signal to adjust a magnetic field of an objective lens contained in the SEM system during operation.

8. The non-transitory computer-readable medium of claim 1 or 2, wherein adjusting the beam position comprises: adjusting the beam position by offsetting a magnetic field disturbance caused by the movement of the wafer stage at the third velocity.

9. The non-transitory computer-readable medium of claim 1 or 2, wherein adjusting the position of the beam comprises: generating a control signal to adjust one of the heights of the sample.

10. A non-transitory computer-readable medium as claimed in claim 1 or 2, wherein the wafer stage includes a conductor.

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