Charged particle detection system

Abstract

A charged particle beam apparatus is provided that is configured to guide a charged particle beam onto a sample. The charged particle beam apparatus comprises a detection system having a first detection surface configured to generate an electrical signal in response to signal particles generated by the sample in response to the charged particle beam, and a second detection surface configured to generate an electrical signal in response to incident secondary particles or backscattered particles generated by the first detection surface in response to the signal particles, the second detection surface defining a second hole so that the signal particles can pass to the first detection surface.

Description

[Technical Field]

[0001] Cross-reference of related applications

[0001] This application claims priority to European / U.S. Patent Application No. 23190948.2 filed on 10 August 2023 and European Patent Application No. 24186398.4 filed on 3 July 2024, both of which are incorporated herein by reference in their entirety.

[0002]

[0002] This specification relates to charged particle detection, and more specifically to systems and methods that may be applicable to charged particle beam detection. [Background technology]

[0003]

[0003] Detectors may be used to sense physically observable phenomena. For example, charged particle beam tools such as electron microscopes may include a detector that receives charged particles projected from a sample and outputs a detection signal. The detection signal can be used to reconstruct an image of the sample structure under inspection and can be used, for example, to reveal defects in the sample. The detection of defects in samples is becoming increasingly important in the manufacture of semiconductor devices, which may include a large number of densely integrated miniature integrated circuit (IC) components. For this purpose, dedicated inspection tools may be provided.

[0004]

[0004] In some applications in the field of inspection, such as microscopy using a scanning electron microscope (SEM), an electron beam may be scanned across a sample to extract information from backscattered or secondary electrons generated from the sample. Backscattered electrons (or more commonly backscattered particles) and secondary electrons (or more commonly secondary particles) generated by the sample are sometimes collectively referred to as back particles. In the relevant technical field, electron detection systems in SEM tools may include detectors configured to detect electrons arriving from the sample. Existing charged particle beam tools typically include semiconductor-based detectors that generate electron-hole pairs when backscattered or secondary particles are incident on the detector. The electron-hole pairs generated in the detector as backscattered or secondary particles form an electric current, which reflects the number of particles incident from the sample to the detector.

[0005]

[0005] In related technologies, the current generated by the detector may not accurately reflect the number of return particles incident from the sample to the detector. One cause of this discrepancy is particle loss due to the interaction between the return particles and the detector surface. Return particles may form further backscattered particles through elastic interaction with the detection surface, or they may form further secondary particles or partially backscattered electrons through inelastic interaction with the detection surface. In some cases, return particles undergo partial backscattering, and the particles undergo scattering events after depositing some of their energy within the detector.

[0006]

[0006] Most semiconductor-based detectors known in the art are silicon-based. Germanium-based semiconductor detectors offer many advantages over silicon detectors, such as improved signal and energy resolution. Furthermore, germanium has a higher density and atomic number than silicon, which means that in germanium, the penetration depth of the charged particle beam into the sample surface is lower than in silicon. Therefore, for a charged particle beam of a given energy, most incident charged particles interact with the detector at a shorter distance in a germanium-based detector than in a silicon-based detector. Consequently, germanium detectors are generally thinner than silicon detectors, making the setup of the detection system more flexible. However, in germanium-based detectors, backscattering of retuning particles is worsened due to the high atomic number of germanium. In addition, there are not many semiconductor materials with an atomic number lower than silicon, which means that there are few options for semiconductor-based detectors with low atomic numbers. Therefore, there is a need to improve the detection efficiency of detectors containing elements with relatively high atomic numbers.

[0007]

[0007] Patent Document 1 discloses an optical column equipped with two detectors, in which return electrons reach the backscatter electron detector via the secondary electron detector. This configuration makes it possible to detect secondary electrons and backscatter electrons with the two detectors, respectively. However, return electrons may still interact elastically or inelastically with either of the detectors, which means that the return electrons may not be detected.

[0008]

[0008] [Patent Document 1] H Jaksch, JP Vermeulen, New Developments in Gemini (registered trademark) Fesem Technology, Microscopy Today, Volume 13, Issue 2, 1 March 2005, Pages 8-11, https: doi.org / 10.1017 / S1551929500051397. [Overview of the Initiative]

[0009]

[0009] According to a first aspect of the present invention, a charged particle beam apparatus is provided which is configured to guide a charged particle beam onto a sample, the charged particle beam apparatus includes a detection system comprising: a first detection surface configured to generate an electrical signal in response to signal particles generated by the sample in response to a charged particle beam; and a second detection surface configured to generate an electrical signal in response to incident secondary particles or backscattered particles generated by the first detection surface in response to the signal particles, the second detection surface defining a second hole so that the signal particles can pass to the first detection surface.

[0010]

[0010] According to a second aspect of the present invention, a non-temporary computer-readable medium is provided having an instruction, when executed by a computer, that causes the computer to execute a method for detecting particles in a charged beam apparatus, the method comprising: detecting one or more return particles generated by a sample in response to a charged particle beam being incident on the sample using a first detection surface; and detecting one or more particles generated by the first detection surface in response to the return particles being incident on the first detection surface using a second detection surface.

[0011]

[0011] According to a third aspect of the present invention, a charged particle beam apparatus is provided which is configured to guide a charged particle beam onto a sample, the charged particle beam apparatus includes a detection system which comprises: a first detector having a first detection surface configured to generate a first electrical signal in response to a first signal particle being incident on a first detection surface, the first detector having a first hole which allows the charged particle beam to pass through the hole to reach the sample, the first signal particle being generated by the sample in response to the charged particle beam being incident on the sample; and a second detector having a second detection surface configured to generate a second electrical signal in response to a second signal particle being incident on a second detection surface, the second detector having a second hole which allows the charged particle beam to pass through the hole to reach the sample, and the first signal particle being generated by the first detector in response to the first signal particle being incident on the first detection surface.

[0012]

[0012] Further embodiments, features, and advantages of the present invention, as well as the structure and operation of various embodiments, features, and advantages of the present invention, will be described in detail below with reference to the accompanying drawings.

[0013]

[0013] The above and other aspects of the present disclosure will become more apparent from the description of the exemplary embodiments in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0014] [Figure 1]

[0014] This is a schematic diagram showing an exemplary electron beam inspection (EBI) system consistent with embodiments of the present disclosure. [Figure 2A-2C]

[0015] This is a schematic diagram showing an exemplary electron beam tool, which may be part of the exemplary electron beam inspection system of Figure 1, consistent with embodiments of the present disclosure. [Figure 3]

[0016] This is a schematic diagram showing a cross-sectional view of a conventional charged particle beam apparatus. [Figure 4]

[0017] It is a schematic diagram showing a cross-sectional view of a charged particle beam apparatus according to an embodiment of the present disclosure. [Figure 5A]

[0018] It is a schematic diagram showing a cross-sectional view of a charged particle beam apparatus according to an embodiment of the present disclosure. [Figure 5B]

[0019] It is a schematic diagram showing a cross-sectional view of a charged particle beam apparatus according to an embodiment of the present disclosure. [Figure 6A]

[0020] It is a schematic diagram showing a cross-sectional view of a charged particle beam apparatus according to an embodiment of the present disclosure. [Figure 6B]

[0021] It is a schematic diagram showing a cross-sectional view of a charged particle beam apparatus according to an embodiment of the present disclosure. [Figure 6C]

[0022] It is a schematic diagram showing a cross-sectional view of a charged particle beam apparatus according to an embodiment of the present disclosure. [Figure 6D]

[0023] It is a schematic diagram showing a cross-sectional view of a charged particle beam apparatus according to an embodiment of the present disclosure. [Figure 7]

[0024] It is a graph showing the collection efficiency of the second detection surface as a function of the distance between the first detection surface and the second detection surface. [Figures 8A-8D]

[0025] It shows a possible embodiment of the second detection surface. MODES FOR CARRYING OUT THE INVENTION

[0015]

[0026] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the drawings. The following description refers to the accompanying drawings, in which the same numerals in different drawings represent the same or similar elements unless otherwise stated. The embodiments set forth in the following description of exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of apparatuses, systems, and methods consistent with aspects related to the subject matter that may be recited in the appended claims.

[0016]

[0027] Aspects of this application relate to a system and method for detecting charged particle beams. The system and method can utilize the counting of charged particles such as electrons and may be useful in inspection tools such as scanning electron microscopes (SEMs). Inspection tools may also be called evaluation tools or evaluation devices. Inspection tools may be used in the manufacturing process of integrated circuit (IC) components. In order to achieve the increased computing power of today's electronic devices, the physical size of the device may be reduced while the integration density of circuit components such as transistors, capacitors, and diodes on the IC chip is greatly increased. For example, in a smartphone, an IC chip (which may be the size of a thumbnail) may contain more than 2 billion transistors, and the size of each transistor is less than 1 / 1,000th the size of a human hair. Naturally, the manufacturing of semiconductor ICs is a complex process involving hundreds of individual steps. If an error occurs in even one step, it can have a dramatic impact on the functionality of the final product. The goal of the manufacturing process is to improve the overall yield of the process. For example, to achieve a 75% yield in a 50-step process, the yield of each individual step must exceed 99.4%. If the yield of an individual step is 95%, the overall process yield will drop to 7%.

[0017]

[0028] It is becoming increasingly important to ensure the ability to detect defects with high accuracy and resolution while maintaining high throughput (defined, for example, as the number of wafers processed per hour). High process yield and high wafer throughput can be affected by the presence of defects, especially when operator intervention is involved. Therefore, the detection and identification of micro- and nano-sized defects using inspection tools (such as SEM) is crucial to maintaining high yield and low costs.

[0018]

[0029] In some inspection tools, a sample can be inspected by scanning the sample surface with a beam of high-energy electrons. Due to interactions at the sample surface, secondary or backscattered electrons (return electrons) may be generated from the sample, and these electrons can then be detected by a detector. An image of the sample is formed pixel by pixel, and the value of a pixel is determined by the number of return electrons detected by the detector.

[0019]

[0030] Backscattered or secondary electrons generated by the sample can undergo elastic or inelastic scattering events. In some cases, electrons scattered by the detector may not be detected, and these undetected electrons may not contribute to the signal used to form an image of the sample. When electrons undergo elastic scattering events, such as elastic scattering with the detector, no energy is lost by the electrons. When electrons undergo inelastic scattering events, such as inelastic scattering with the detector, the electrons contribute some energy to the detector. The proportion of backscattered electrons that undergo scattering events and go undetected is determined by several factors. For example, detectors containing elements with higher atomic numbers are more likely to backscatter retuning electrons.

[0020]

[0031] The detection of re-tuned particles is often performed using solid-state semiconductor-based detectors. When a return particle with energy higher than the semiconductor's band gap enters the detector, electron-hole pairs are generated within the detector, creating an electric current. Often, semiconductor-based detectors are silicon-based detectors.

[0021]

[0032] The inventors have found that the collection efficiency of return particles can be improved by providing a second detector configured to detect particles that have interacted with the first detector.

[0022]

[0033] Without limiting the scope of this disclosure, some embodiments may be described in relation to providing detectors and detection methods in systems utilizing electron beams. However, this disclosure is not limited in that way. Other types of charged particle beams may also be applied. Furthermore, the systems and methods for detection may also be used in other imaging systems such as optical imaging, photon detection, X-ray detection, and ion detection.

[0023]

[0034] As used herein, unless otherwise specified, the term “or” encompasses all possible combinations, except where impossible. For example, if it is stated that a component includes A or B, then unless otherwise specified or impossible, the component may include A, or B, or A and B. As a second example, if it is stated that a component includes A, B, or C, then unless otherwise specified or impossible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0024]

[0035] Referring here to Figure 1, Figure 1 shows an exemplary electron beam inspection (EBI) system 10 which may include a detector, consistent with embodiments of the present disclosure. The EBI system 10 may be used for imaging. As shown in Figure 1, the EBI system 10 includes a main chamber 11, a load / lock chamber 20, an electron beam tool 100, and an instrument front-end module (EFEM) 30. The electron beam tool 100 is located in the main chamber 11. The EFEM 30 includes a first loading port 30a and a second loading port 30b. The EFEM 30 may include additional loading ports. The first loading port 30a and the second loading port 30b receive a wafer-front-opening integrated pod (FOUP) containing a wafer to be inspected (e.g., a semiconductor wafer or a wafer made of other materials) or a sample (wafers and samples are sometimes collectively referred to as "samples" in this specification).

[0025]

[0036] One or more robotic arms (not shown) of the EFEM30 may transfer wafers to the load / lock chamber 20. The load / lock chamber 20 is connected to a load / lock vacuum pump system (not shown) that removes gas molecules from within the load / lock chamber 20 to a first pressure below atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) may transfer wafers from the load / lock chamber 20 to the main chamber 11. The main chamber 11 is connected to a main chamber vacuum pump system (not shown) that removes gas molecules from within the main chamber 11 to a second pressure below the first pressure. After reaching the second pressure, the wafers are inspected by an electron beam tool 100. The electron beam tool 100 may be a single-beam system or a multi-beam system. A controller 109 is electronically connected to the electron beam tool 100 and may similarly be electronically connected to other components. The controller 109 may be a computer configured to perform various controls of the EBI system 10. In Figure 1, the controller 109 is shown as being outside the structure that includes the main chamber 11, the load / lock chamber 20, and the EFEM 30, but it should be understood that the controller 109 may also be part of this structure.

[0026]

[0037] Figure 2A shows a charged particle beam apparatus. In this charged particle beam apparatus, the inspection system may include a multi-beam inspection tool that uses multiple primary electron beamlets to simultaneously scan multiple locations on the sample.

[0027]

[0038] As shown in Figure 2A, the electron beam tool 100A (also referred to herein as apparatus 100A) may include an electron source 202, a gun aperture 204, a focusing lens 206, a primary electron beam 210 emitted from the electron source 202, a source conversion unit 212, a plurality of beamlets 214, 216, and 218 of the primary electron beam 210, a primary projection optical system 220, a wafer stage (not shown in Figure 2A), a plurality of secondary electron beams 236, 238, and 240, a secondary optical system 242, and an electron detection device 244. The electron source 202 can generate primary particles such as electrons of the primary electron beam 210. A controller, an image processing system, etc., may be coupled to the electron detection device 244. The primary projection optical system 220 may include a beam separator 222, a deflection scanning unit 226, and an objective lens 228. The electron detection device 244 may include detection sub-regions 246, 248, and 250.

[0028]

[0039] The electron source 202, gun aperture 204, focusing lens 206, radiation source conversion unit 212, beam separator 222, deflection scanning unit 226, and objective lens 228 may be aligned with the primary optical axis 260 of the device 100A. The secondary optical system 242 and electron detection device 244 may be aligned with the secondary optical axis 252 of the device 100A.

[0029]

[0040] The electron source 202 may include a cathode, an extractor, or an anode, and primary electrons can be emitted from the cathode, extracted, or accelerated to form a primary electron beam 210 with a (virtual or actual) crossover 208. The primary electron beam 210 can be visualized as if it were being emitted from the crossover 208. The gun aperture 204 can block peripheral electrons from the primary electron beam 210 to reduce the size of probe spots 270, 272, and 274.

[0030]

[0041] The radiation source conversion unit 212 may include an image-forming element array (not shown in Figure 2A) and a beam-limiting aperture array (not shown in Figure 2A). Examples of the radiation source conversion unit 212 are described in U.S. Patent No. 9,691,586, U.S. Patent Application Publication No. 2017 / 0025, and International Patent Application No. PCT / EP2017 / 084429 (all of which are incorporated herein by reference in their entirety). The image-forming element array may include an array of micro-deflectors or microlenses. The image-forming element array can form multiple parallel images (virtual or real images) of the crossover 208 with multiple beamlets 214, 216, and 218 of the primary electron beam 210. The beam-limiting aperture array can limit the multiple beamlets 214, 216, and 218.

[0031]

[0042] The focusing lens 206 can focus the primary electron beam 210. The currents in the beamlets 214, 216, and 218 downstream of the radiation source conversion unit 212 can be changed by adjusting the focusing force of the focusing lens 206 or by changing the radial size of the corresponding beam limiting apertures in the beam limiting aperture array. The focusing lens 206 may be a movable focusing lens, which can be configured such that the position of its first principle plane is movable. The movable focusing lens may be configured to be magnetic, so that the off-axis beamlets 216 and 218 may land on the beamlet limiting aperture at a certain rotation angle. The rotation angle changes with the focusing force of the movable focusing lens and the position of the first principle plane. In some embodiments, the movable focusing lens may be a movable anti-rotation focusing lens, which includes an anti-rotation lens having a movable first principle plane. A movable focusing lens is further described in U.S. Patent Application Publication No. 2017 / 0025241, which is incorporated herein by reference in its entirety.

[0032]

[0043] The objective lens 228 can focus beamlets 214, 216, and 218 onto the wafer 230 to be inspected, and can form multiple probe spots 270, 272, and 274 on the surface of the wafer 230.

[0033]

[0044] The beam separator 222 may be a Wien filter type beam separator that generates an electrostatic dipole field and a magnetic dipole field. In some embodiments, when these fields are applied, the force exerted by the electrostatic dipole field on the electrons of beamlets 214, 216, and 218 may be equal in magnitude and opposite in direction to the force exerted by the magnetic dipole field on the electrons. Thus, the beamlets 214, 216, and 218 can pass straight through the beam separator 222 with zero deflection angle. However, the total dispersion of beamlets 214, 216, and 218 generated by the beam separator 222 may be non-zero. The beam separator 222 can separate the secondary electron beams 236, 238, and 240 from the beamlets 214, 216, and 218 and guide the secondary electron beams 236, 238, and 240 toward the secondary optical system 242.

[0034]

[0045] The deflection scanning unit 226 can deflect beamlets 214, 216, and 218 to scan probe spots 270, 272, and 274 across the surface area of ​​wafer 230. In response to beamlets 214, 216, and 218 being incident on probe spots 270, 272, and 274, secondary electron beams 236, 238, and 240 may be emitted from wafer 230. The secondary electron beams 236, 238, and 240 may contain electrons with a certain energy distribution, including secondary electrons and backscattered electrons. The secondary optical system 242 can focus the secondary electron beams 236, 238, and 240 onto detection sub-regions 246, 248, and 250 of the electron detection device 244. The detection subregions 246, 248, and 250 may be configured to detect the corresponding secondary electron beams 236, 238, and 240 and generate corresponding signals used to reconstruct an image of the surface area of ​​the wafer 230.

[0035]

[0046] Figure 2A shows an example of the electron beam tool 100 as a multi-beam tool using multiple beamlets, but embodiments of the present disclosure are not limited thereto. For example, the electron beam tool 100 may be a single-beam tool that uses only one primary electron beam to scan locations on the wafer one at a time.

[0036]

[0047] As shown in Figure 2B, the electron beam tool 100B (also referred to herein as apparatus 100B) may be a single-beam inspection tool used in the EBI system 10. Apparatus 100B includes a wafer holder 136 supported by an electric stage 134 to hold a wafer 150 to be inspected. The electron beam tool 100B includes an electron emitter, which may include a cathode 103, an anode 121, and a gun aperture 122. The electron beam tool 100B further comprises a beam limiting aperture 125, a focusing lens 126, a column aperture 135, an objective lens assembly 132, and a detection system 144. In some embodiments, the objective lens assembly 132 may be a modified SORIL lens, which includes a pole piece 132a, a control electrode 132b, a deflector 132c, and an excitation coil 132d. In the imaging process, the electron beam 161 emitted from the tip of the cathode 103 is accelerated by the anode 121 voltage, passes through the gun aperture 122, the beam limiting aperture 125, and the focusing lens 126, and is focused by the modified SORIL lens to a probe spot 170 that can strike the surface of the wafer 150. The probe spot 170 can be scanned across the surface of the wafer 150 by a deflector such as the deflector 132c or other deflectors in the SORIL lens. Secondary particles or scattered primary particles, such as secondary electrons or scattered primary electrons emitted from the wafer surface, are collected by the detection system 144 to determine the beam intensity, thereby allowing for the reconstruction of an image of the area of ​​interest on the wafer 150.

[0037]

[0048] An image processing system 199 comprising an image acquirer 120, storage 130, and a controller 109 may also be provided. The image acquirer 120 may include one or more processors. For example, the image acquirer 120 may include a computer, server, mainframe host, terminal, personal computer, any type of mobile computing device, or a combination thereof. The image acquirer 120 may be connected to the detection system 144 of the electron beam tool 100B through a medium such as a conductor, fiber optic cable, portable storage medium, IR, Bluetooth, the internet, a wireless network, wireless radio, or a combination thereof. The image acquirer 120 can receive signals from the detection system 144 and construct an image. Thus, the image acquirer 120 can acquire an image of the wafer 150. The image acquirer 120 can also perform various post-processing functions such as contour generation and overlaying indicators onto the acquired image. The image acquirer 120 may be configured to perform adjustments such as brightness and contrast of the acquired image. The storage 130 may be a storage medium such as a hard disk, random access memory (RAM), cloud storage, or other types of computer-readable memory. The storage 130 may be coupled with the image acquirer 120 and used to store scanned raw image data as the original image and to store the post-processed image. 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.

[0038]

[0049] In some embodiments, the image acquirer 120 may acquire one or more images of a sample based on imaging signals received from the detection system 144. The imaging signals may correspond to scanning operations for charged particle imaging. The acquired image may be a single image containing multiple imaging areas that may include various features of the wafer 150. This single image may be stored in storage 130. Imaging may be performed based on imaging frames.

[0039]

[0050] The focusing and illumination optics of an electron beam tool may include or be complemented by electromagnetic quadrupole lenses. For example, as shown in Figure 2B, the 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, the first quadrupole lens 148 may be controlled to adjust the beam current, and the second quadrupole lens 158 may be controlled to adjust the beam spot size and beam shape.

[0040]

[0051] Figure 2B shows a charged particle beam apparatus. In this charged particle beam apparatus, the inspection system can use a single primary beam which may be configured to generate secondary electrons by interacting with the wafer 150. As in the embodiment shown in Figure 2B, the detection system 144 may be positioned along the optical axis 105. The primary electron beam may be configured to move along the optical axis 105. Therefore, the detection system 144 may include a hole in its center so that the primary electron beam can pass through and reach the wafer 150. However, some embodiments may use a detection system positioned off-axis with respect to the optical axis along which the primary electron beam moves. For example, as in the embodiment shown in Figure 2A, a beam separator 222 may be provided to guide the secondary electron beam toward the off-axis detection system. The beam separator 222 may be configured to redirect the secondary electron beam by an angle α.

[0041]

[0052] Next, with reference to Figure 2C, we consider another example of a charged particle beam apparatus. The electron beam tool 100C (also referred to herein as apparatus 100C) may be an example of the electron beam tool 100, or it may be similar to the electron beam tool 100A shown in Figure 2A.

[0042]

[0053] As shown in Figure 2C, the beam separator 222 may be a Wien filter type beam separator that generates an electrostatic dipole field and a magnetic dipole field. In some embodiments, when these fields are applied, the force exerted on the electrons of beamlets 214, 216, and 218 by the electrostatic dipole field may be equal in magnitude and opposite in direction to the force exerted on the electrons by the magnetic dipole field. Thus, the beamlets 214, 216, and 218 can pass straight through the beam separator 222 with zero deflection angle. However, the total dispersion of beamlets 214, 216, and 218 produced by the beam separator 222 may be non-zero. With respect to the dispersion surface 224 of the beam separator 222, Figure 2C shows the dispersion of a beamlet 214 having nominal energy V0 and energy width ΔV into a beamlet portion 262 corresponding to energy V0, a ​​beamlet portion 264 corresponding to energy V0 + ΔV / 2, and a beamlet portion 266 corresponding to energy V0 - ΔV / 2. The beam separator 222 can make the sum of the forces acting on the electrons in the secondary electron beams 236, 238, and 240 non-zero. The beam separator 222 can separate the secondary electron beams 236, 238, and 240 from the beamlets 214, 216, and 218 and guide the secondary electron beams 236, 238, and 240 toward the secondary optical system 242.

[0043]

[0054] A semiconductor electron detector (sometimes called a "PIN detector") can be used in the apparatus 100 of the EBI system 10. The EBI system 10 may be a high-speed wafer imaging SEM including an image processor. The electron beam generated by the EBI system 10 may irradiate the surface of the sample or penetrate the sample. The EBI system 10 may be used to image the sample surface or subsurface structures, for example, to analyze layer alignment. In some embodiments, the EBI system 10 can detect and report process defects related to the manufacturing of the semiconductor wafer by, for example, comparing the SEM image to a device layout pattern or to an SEM image of the same pattern at another location on the wafer under inspection. The PIN detector may include a silicon PIN diode that can operate under a negative bias. The PIN detector may include a PIN diode containing an element other than silicon. The PIN detector may be configured such that incident electrons generate a relatively large and clear detection signal. In some embodiments, the PIN detector may be configured such that one photon can generate only one pair of electrons and holes, while one incident electron can generate multiple pairs of electrons and holes. PIN detectors used for counting electrons can have many differences compared to photodiodes used for photon detection, as will be discussed below.

[0044]

[0055] Now, refer to Figure 3. Figure 3 shows a cross-sectional view of a prior art charged particle beam apparatus equipped with a detection system 300, as a comparative example.

[0045]

[0056] According to the comparative example shown in Figure 3, the detection system 300 includes a single in-column detector 301 configured to detect return electrons. When return electrons are incident on the surface of the detector 301, some of the return electrons are scattered, and there is no means for detecting those scattered return electrons. The detector 301 has a radius r0, and the detector 301 is a hole with radius r0 that allows a charged particle beam to pass through this hole to reach the sample surface. iA hole having [a certain characteristic] is defined.

[0046]

[0057] Now, refer to Figure 4. Figure 4 shows a schematic diagram of an exemplary structure of the detection system 400. The detection system 400 may be provided as a detector 144 or electronic detection device 244 in relation to Figures 2A, 2B, and 2C.

[0047]

[0058] According to the configuration in Figure 4, the detection system 400 includes a first detection surface 401 and a second detection surface 402. The first detection surface may be positioned on a first detector. The second detection surface may be positioned on a second detector. The charged particle beam is indicated by a vertical line. The first detection surface 401 is configured to generate an electrical signal in response to signal particles (e.g., return electrons) generated by the sample 150 in response to the charged particle beam. The return particles (e.g., return electrons) are schematically indicated by curved arrows emanating from the sample 150. In one embodiment, the first detection surface may define a first hole, which allows the charged particle beam to pass through the hole to the sample surface. This embodiment may be used when the detection system is positioned as a detector 144, allowing the charged particle beam to pass through it to the sample surface. In another embodiment, the first detection surface does not define a hole. This embodiment may be used when the detection system is provided as an electron detection device 244, i.e., when the detection system is provided off-axis. In one embodiment, the first hole is circular and has a radius of r 1i The second detection surface 402 is configured to generate an electrical signal in response to incident secondary particles (e.g., secondary electrons) or backscattered particles (e.g., backscattered electrons) generated by the first detection surface 401 in response to signal particles (e.g., return electrons). These particles (e.g., electrons) emitted by the first detection surface are indicated by arrows exiting the first detection surface. The second detection surface defines a second hole, which allows a charged particle beam to pass to the sample surface and allows signal particles to pass to the first detection surface. In one embodiment, the second hole is circular with radius r2i . It is. The radius r of the first hole 1i and the radius r of the second hole 2i may be the same, or the radius r of the second hole 2i may be larger than the radius r of the first hole 1i may be larger than that, or the radius r of the first hole 1i may be larger than the radius r of the second hole 2i may be larger than that. In one embodiment, when the detection system 400 is provided as an electronic detection device 244 that is not aligned with the primary optical axis, the first detection surface may not have the first hole. As described with reference to FIGS. 8A to 8D, the first detection surface and / or the second detection surface may have a plurality of different configurations.

[0048]

[0059] The first detection surface 401 may be any suitable detection surface for detecting returned particles. For example, the first detection surface 401 may be a semiconductor-based detector, a silicon-based PIN detector, a germanium-based PIN detector, or the like. The second detection surface 402 may be any suitable detection surface for detecting incident backscattered particles or secondary particles generated by the first detection surface. For example, the second detection surface 402 may be a semiconductor-based detector, a silicon-based PIN detector, a germanium-based PIN detector, or the like. The first detection surface 401 and the second detection surface 402 in the detection system 400 are not necessarily the same type of detector. In one embodiment, a germanium-based detector may be used instead of a silicon-based detector.

[0049]

[0060] Reference is now made to FIGS. 5A and 5B. These figures show cross-sectional views of a charged particle beam apparatus according to an embodiment of the present disclosure.

[0050]

[0061] The first detection surface 401 may be arranged perpendicular to the charged particle beam. Alternatively, a radial line of the first detection surface may form a first angle β1 with a plane perpendicular to the charged particle beam. The angle β1 may be 45° or less, preferably 30° or less, or more preferably 15° or less.

[0051]

[0062] The second detection surface 402 may be positioned perpendicular to the charged particle beam. Alternatively, the radial line of the first detection surface may form a first angle β2 with a plane perpendicular to the charged particle beam. The angle β2 may be 45° or less, preferably 30° or less, or more preferably 15° or less.

[0052]

[0063] By setting the first angle β1 to a value greater than 0°, the collection efficiency of backscattered electrons generated by the sample surface can be increased. Backscattered electrons are emitted from the sample at various angles, but most electrons are emitted perpendicular to the sample surface or near the perpendicular to the sample surface. If the first angle β1 is set to 0°, electrons emitted perpendicular to the surface or at angles close to the perpendicular to the surface may pass through the second hole of the second detector and not reach the second detection surface. By tilting the first detection surface so that the first angle β1 is formed, the rate of electron loss can be reduced.

[0053]

[0064] As described above, by setting the second angle β2 to a value greater than 0°, the collection efficiency of electrons generated by the first detection surface is improved.

[0054]

[0065] The first angle β1 and the second angle β2 may be equal to each other or they may be different.

[0055]

[0066] Now, refer to Figures 6A, 6B, 6C, and 6D. These figures show cross-sectional views of a charged particle beam apparatus according to embodiments of the present disclosure.

[0056]

[0067] The charged particle beam apparatus may include an annular detection surface arranged to surround the charged particle beam. As shown in Figures 6A, 6B, and 6C, the annular detection surface may be included as a third detection surface in addition to the first and second detection surfaces. Alternatively, the annular detection surface may be provided as a second detection surface, as shown in Figure 6D. The annular detection surface may be placed on a detector.

[0057]

[0068] The annular detection surface (a third detection surface 403 as shown in Figures 6A to 6C, or a second detection surface 402 as shown in Figure 6D) is configured to generate an electrical signal in response to incident secondary particles (e.g., secondary electrons) or backscattered particles (e.g., backscattered electrons) generated by the first detection surface 401 in response to signal particles (e.g., return electrons). The annular detection surface defines a hole, which allows a charged particle beam to pass through the hole to the sample surface. The hole may be circular and have a radius of r 3i That's fine.

[0058]

[0069] The first detection surface, the second detection surface, and the third detection surface may each include multiple segments.

[0059]

[0070] While the use of circular, partially circular, annular, and partially annular detection surfaces has been described, the shape of the detector is not limited to these. For example, the detection surface may include partially annular or partially circular segments. In addition, the detection surface segments may have shapes selected from the group consisting of circular, elliptical, ring-shaped, square, rectangular, rhombic, and oblique shapes.

[0060]

[0071] Several possible configurations of the detection surface will be described with reference to Figures 8A to 8D. These figures show examples of the second detection surface 402a, 402b, 402c, and 402d. The first detection surface 401 may be formed of any one of the shapes shown in Figures 8A to 8D. Those skilled in the art will understand, based on the teachings herein, that other shapes are also possible. The features of the second detection surface described with reference to Figures 8A to 8D can also be applied to the first detection surface.

[0061]

[0072] In one embodiment, the hole (second hole) of the second detection surface 402 may be located in the central portion of the second detection surface 402. The second detection surface 402 may surround the second hole. The second detection surface 402 may at least partially surround the second hole. Optionally, the second detection surface 402 may completely surround the second hole. For example, Figure 8A shows a second detection surface 402a that completely surrounds the second hole.

[0062]

[0073] The boundary between the second detection surface 402 and the second hole (i.e., the outer perimeter of the hole) may be any suitable shape selected from a list including substantially circular, substantially elliptical, substantially rectangular, or substantially hexagonal shapes. Multiple holes may be provided, each of which may be any suitable shape.

[0063]

[0074] The second hole may be located in the central portion of the second detection surface 402. In one example, the second hole may be located at the center of the second detection surface. In an alternative embodiment, the second hole may be located off-center. Optionally, the hole may be circular, substantially circular, or of another shape.

[0064]

[0075] In one embodiment, the second hole may extend from one edge of the second detection surface 402 to another edge of the second detection surface 402. In other words, the second detection surface 402 may be provided as multiple segments. Figure 8B shows a second detection surface 402b defined by two semicircular segments, and Figure 8C shows a second detection surface 402c defined by two rectangular segments. In some embodiments, the number of segments may be more than two. For example, the second detection surface may comprise three or more segments separated by a second hole.

[0065]

[0076] If the outer edge of the second detection surface 402 is circular, the second hole may extend from a point on the circular edge to a point on the opposite side in the diametrical direction. In other words, the second hole may bisect the detection surface into a semicircular segment. In another embodiment, the hole may extend between two other points, resulting in two segments of different shapes. The hole does not necessarily have to extend in a straight line; it may be curved, angled, or of another shape.

[0066]

[0077] If the outer edge of the second detection surface 402 is rectangular or square, the second hole may extend from a point on one side of the edge to the opposite edge. In other words, the second hole may bisect the detection surface. In another embodiment, the hole may extend between two other points, resulting in two segments of different shapes.

[0067]

[0078] Other shapes are possible for the second detection surface 402, which may have a second hole, as described in the above embodiment. For example, the second detection surface may be hexagonal or have another shape.

[0068]

[0079] In one embodiment, the second hole may extend from the central portion of the second detection surface to the edge of the second detection surface. Figure 8D shows an example of a second detection surface 402d having a second hole that extends from the central portion to the edge of the second detection surface.

[0069]

[0080] As shown with reference to the non-limiting examples in Figures 8A to 8D, the second detection surface has a shape that allows the passage of secondary or backscattered particles generated by the first detection surface in response to the incidence of signal particles onto the first detection surface. The second detection surface may have any suitable shape that satisfies this function.

[0070]

[0081] The shape of the first detection surface 401 is not particularly limited. The first detection surface 401 may take any of the shapes described with reference to Figures 8A to 8D. In other words, the first detection surface 401 may define a first hole.

[0071]

[0082] The first hole may be located in the central portion of the first detection surface 401. The first detection surface 401 may surround the first hole. The first detection surface 401 may completely surround the first hole. The boundary between the first detection surface 401 and the first hole may be any suitable shape selected from a list including substantially circular, substantially rectangular, or substantially hexagonal shapes. The first hole may extend from one edge of the first detection surface 401 to another edge of the first detection surface. The first hole may extend from the central portion of the first detection surface 401 to the edge of the first detection surface 401.

[0072]

[0083] The shape of the outer edges of the first detection surface 401 and the second detection surface 402 is not particularly limited and may be circular (as shown in Figures 8A, 8B, and 8D), rectangular / square (as shown in Figure 8C), or another shape. The shapes of the first detection surface 401 and the second detection surface 402 may be different.

[0073]

[0084] In some embodiments, an acceleration unit is provided, configured to apply a potential difference between a first detection surface and a second detection surface. The acceleration unit may be further configured to apply different potentials between the first detection surface and a third detection surface. According to this embodiment, electrons generated by the first detection surface are accelerated toward the second detection surface (and optionally the third detection surface), which means that detection efficiency is improved.

[0074]

[0085] In some embodiments, a detector, such as one of a first detector, a second detector, and a third detector, may communicate with a controller that controls the charged particle beam system. The controller can instruct components of the charged particle beam system to perform various functions, such as controlling a charged particle source to generate a charged particle beam and controlling a deflector to scan the charged particle beam. The controller can also perform various other functions, such as adjusting the sampling rate of the detector, resetting the sensing element, or performing image processing. The controller may include storage, which is a storage medium such as a hard disk, random access memory (RAM), or other types of computer-readable memory. The storage can be used to store scanned raw image data as source images or to store post-processed images. A non-temporary computer-readable medium may be provided for the processor of the controller 109 to store instructions for performing charged particle beam detection, sampling period determination, image processing, or other functions and methods consistent with the present disclosure. Common forms of non-temporary media include, for example, floppy disks, flexible disks, hard disks, solid-state drives, magnetic tapes or any other magnetic data storage media, CD-ROMs, any other optical data storage media, any physical media having a pattern of holes, ROMs, PROMs and EPROMs, flash EPROMs or any other flash memory, NVRAMs, caches, registers, any other memory chips or cartridges, and network-connected versions thereof.

[0075]

[0086] The charged particle beam apparatus according to the present invention may further comprise a charged particle detection unit. The charged particle detection unit is configured to assign electrical signals generated by a first detector and electrical signals generated by a second detector to a single charged particle count, which is done in response to a determination that the sum of the energies of the first and second electrical signals received within a given time frame matches a predicted energy of secondary or backscattered particles generated by the sample. In one embodiment, the predicted energy of secondary or backscattered particles generated by the sample (i.e., total energy) is approximately equal to the landing energy of the charged particle when it is incident on the sample. In one embodiment, the landing energy is in the range of 0.05 keV to 50 keV. In one embodiment, the time frame may be the sample pixel residence time, which is equal to an interval during which multiple charged particles incident on the first detection surface are assigned to the same pixel. For example, the pixel residence time may be 2.5 ns or more and 40 ns or less. According to this embodiment, it is possible to detect electrons partially backscattered by the first detector.

[0076]

[0087] For example, the first and second detectors may include multiple thresholds to enable correlation of the signals from both detectors. For example, there may be three threshold levels, with the highest threshold corresponding to the total energy deposition and the other two corresponding to 2 / 3 and 1 / 3 of the total energy, respectively. If an incidence with a lower threshold level is counted by the first detector (e.g., 1 / 3 of the total energy), it should be checked whether the second detector detected a signal with residual energy (1 / 3 or 2 / 3 of the total energy) within a given time frame. If a balanced incidence exists, the second signal is very likely caused by electrons generated by the first detection surface (i.e., partially backscattered electrons). Taking this into consideration, the two signals from the first and second detectors are coupled to correspond to a single electron count. If they are not balanced, the lower threshold count is likely noise and should be ignored. In embodiments including a third detector, the same correlation can be performed between the signals generated by the second and third detectors and / or between the signals generated by the first and third detectors.

[0077]

[0088] It should be understood that any phrases in this specification referring to “electron beam,” “secondary electron beam,” or “electron” are not limited thereto, for according to the present invention, the detection system may be configured to detect a charged particle beam containing charged particles that can interact with a sample to generate a secondary charged particle beam.

[0078]

[0089] Now, refer to Figure 7. This figure is a graph showing the collection efficiency of the second detection surface as a function of the distance between the first detection surface and the second detection surface. In Figure 7, the first detection surface and the second detection surface are referred to as the first detector and the second detector, respectively, for simplicity.

[0079]

[0090] Exemplary embodiments of the present invention are described in the following numbered clauses. 1. A charged particle beam apparatus configured to guide a charged particle beam onto a sample, A detection system comprising: a first detection surface configured to generate an electrical signal in response to signal particles generated by a sample in response to a charged particle beam; and a second detection surface configured to generate an electrical signal in response to incident secondary particles or backscattered particles generated by the first detection surface in response to the signal particles, the second detection surface having a second hole that allows the signal particles to pass through to the first detection surface. A charged particle beam device equipped with the following features. 2. The charged particle beam apparatus according to Clause 1, wherein the second hole is located in the central portion of the second detection surface. 3. The charged particle beam apparatus according to Clause 1 or Clause 2, wherein the second detection surface surrounds the second hole. 4. A charged particle beam apparatus as described in any one of clauses 1 to 3, wherein the second detection surface completely surrounds the second hole. 5. A charged particle beam apparatus according to any one of clauses 1 to 4, wherein the boundary between the second detection surface and the second hole is substantially circular, substantially elliptical, substantially rectangular, or substantially hexagonal. 6. The charged particle beam apparatus according to Clause 1, wherein the second hole extends from one edge of the second detection surface to another edge of the second detection surface. 7. The charged particle beam apparatus as described in Clause 1, wherein the second hole extends from the central portion of the second detection surface to the edge of the second detection surface. 8. A charged particle beam apparatus as described in any of clauses 1 to 7, wherein the field of view of the second detection surface includes the first detection surface. 9. A charged particle beam apparatus according to any of clauses 1 to 8, wherein the first detection surface defines a first hole, allowing a charged particle beam to pass through this hole and reach the sample surface. 10. The charged particle beam apparatus according to Clause 9, wherein the first hole is located in the central portion of the first detection surface. 11. The charged particle beam apparatus according to Clause 9 or 10, wherein the first detection surface surrounds the first hole. 12. A charged particle beam apparatus as described in any one of clauses 9 to 11, wherein the first detection surface completely surrounds the first hole. 13. A charged particle beam apparatus according to any one of clauses 9 to 12, wherein the boundary between the first detection surface and the first hole is substantially circular, substantially rectangular, or substantially hexagonal. 14. The charged particle beam apparatus according to Clause 9, wherein the first hole extends from one edge of the first detection surface to another edge of the first detection surface. 15. The charged particle beam apparatus according to Clause 9, wherein the first hole extends from the central portion of the first detection surface to the edge of the first detection surface. 16. A charged particle beam apparatus according to any one of claims 1 to 15, wherein the radial line of the first detection surface forms a first angle β1 with respect to a plane perpendicular to the charged particle beam, which is 45° or less, preferably 30° or less, and more preferably 15° or less. 17. The charged particle beam apparatus described in Clause 16, wherein the first angle β1 is 0°. 18. A charged particle beam apparatus according to any one of the claims 1 to 17, wherein the radial line of the second detection surface forms a second angle β2 with respect to a plane perpendicular to the charged particle beam, which is 45° or less, preferably 30° or less, and more preferably 15° or less. 19. The charged particle beam apparatus described in Clause 18, wherein the second angle β2 is 0°. 20. A charged particle beam apparatus according to any one of clauses 1 to 19, wherein the second detection surface is an annular detection surface and is arranged to surround the charged particle beam. 21. A charged particle beam apparatus according to any one of the clauses 1 to 20, further comprising a third detection surface, the third detection surface being an annular detection surface arranged to surround the charged particle beam. 22. A charged particle beam apparatus according to any one of Clauses 1 to 15, wherein signal particles generated by a sample in response to a charged particle beam are directed away from the axis defined by the charged beam to form a secondary beam. 23. The charged particle beam apparatus according to Clause 22, wherein the radial line of the first detection surface forms a first angle β1 with respect to a plane perpendicular to the secondary beam, which is 45° or less, preferably 30° or less, and more preferably 15° or less. 24. The charged particle beam apparatus described in Clause 23, wherein the first angle β1 is 0°. 25. A charged particle beam apparatus according to any one of the clauses 22 to 24, wherein the radial line of the second detection surface forms a second angle β2 with respect to a plane perpendicular to the secondary beam, which is 45° or less, preferably 30° or less, and more preferably 15° or less. 26. The charged particle beam apparatus described in Clause 25, wherein the first angle β2 is 0°. 27. A charged particle beam apparatus according to any one of clauses 22 to 26, wherein the second detection surface is an annular detection surface and is arranged to surround the secondary beam. 28. A charged particle beam apparatus according to one of the clauses 22-27, further comprising a third detection surface, the third detection surface being an annular detection surface arranged to surround the secondary beam. 29. A charged particle beam apparatus according to Clause 21 or Clause 28, wherein the third detection surface includes multiple segments. 30. A charged particle beam apparatus as described in any one of clauses 1 to 29, wherein the first detection surface includes multiple segments. 31. A charged particle beam apparatus as described in any one of clauses 1 to 30, wherein the second detection surface includes multiple segments. 32. A charged particle beam apparatus according to any one of clauses 1 to 31, further comprising an acceleration unit configured to apply a potential difference between a first detection surface and a second detection surface. 33. A charged particle beam apparatus according to either clause 21 or 28, further comprising an acceleration unit configured to apply a potential difference between a first detection surface and a third detection surface. 34. A charged particle detection unit configured to assign an electrical signal generated by a first detection surface and an electrical signal generated by a second detection surface to a single charged particle count, wherein the assignment is made in response to a determination that the sum of the energies of the first and second electrical signals received within a given time frame matches the predicted energy of secondary or backscattered particles generated by the sample. A charged particle beam apparatus as described in any one of clauses 1 to 33, further comprising: 35. A charged particle beam apparatus as described in Clause 34, wherein a given time frame is equal to the pixel residence time of the charged particle beam on the sample. 36. A charged particle beam apparatus as described in any one of Clauses 1 to 35, wherein the first detection surface is a semiconductor-based detector. 37. A charged particle beam apparatus as described in any one of clauses 1 to 36, wherein the second detection surface is a semiconductor-based detector. 38. A charged particle beam apparatus as described in any one of Clauses 1 to 37, wherein the first detection surface and / or the second detection surface contains germanium. 39. A charged particle beam apparatus as described in any one of Clauses 1 to 38, wherein the first detection surface and / or the second detection surface is made of silicon. 40. A charged particle beam apparatus as described in any one of Clauses 1 to 39, configured to guide multiple charged particle beams into a sample and including an array of sensing elements for each of the multiple charged particle beams. 41. A method for detecting particles in a charged beam apparatus, The steps include detecting one or more return particles generated by the sample in response to a charged particle beam being incident on the sample using a first detection surface, The steps include detecting one or more particles generated by the first detection surface, which are generated in response to a return particle being incident on the first detection surface, using a second detection surface, Methods that include... 42. A charged particle beam apparatus configured to guide a charged particle beam onto a sample, A detection system comprising: a first detector having a first detection surface configured to generate a first electrical signal in response to a first signal particle being incident on the first detection surface, wherein a first hole is defined to allow a charged particle beam to pass through the hole to the sample, and the first signal particle is generated by the sample in response to the charged particle beam being incident on the sample; and a second detector having a second detection surface configured to generate a second electrical signal in response to a second signal particle being incident on the second detection surface, wherein a second hole is defined to allow a charged particle beam to pass through the hole to the sample, and also allows a first signal particle to pass through the hole to the first detection surface, and the second signal particle is generated by the first detector in response to the first signal particle being incident on the first detection surface. A charged particle beam device equipped with the following features. 43. The charged particle beam apparatus as described in Clause 42, wherein the field of view of the second detection surface includes the first detection surface. 44. The charged particle beam apparatus according to clause 42 or 43, wherein the radial line of the first detection surface forms a first angle β1 with respect to a plane perpendicular to the charged particle beam, which is 45° or less, preferably 30° or less, and more preferably 15° or less. 45. The charged particle beam apparatus described in Clause 44, wherein the first angle β1 is 0°. 46. ​​A charged particle beam apparatus according to any one of the claims 42 to 45, wherein the radial line of the second detection surface forms a second angle β2 with respect to a plane perpendicular to the charged particle beam, which is 45° or less, preferably 30° or less, and more preferably 15° or less. 47. The charged particle beam apparatus described in Clause 46, wherein the second angle β2 is 0°. 48. A charged particle beam apparatus according to any one of the clauses 42 to 47, wherein the second detector is an annular detector, and the second detection surface is arranged to surround the charged particle beam. 49. A charged particle beam apparatus according to one of the clauses 42 to 48, further comprising a third detector having a third detection surface, the third detection surface being an annular detection surface arranged to surround the charged particle beam. 50. A charged particle beam apparatus as described in Clause 49, wherein the third detection surface includes multiple segments. 51. A charged particle beam apparatus according to any one of clauses 42 to 50, wherein the first detection surface includes multiple segments. 52. A charged particle beam apparatus according to any one of clauses 42 to 51, wherein the second detection surface includes multiple segments. 53. A charged particle beam apparatus according to any one of the clauses 49 to 50, further comprising an acceleration unit configured to apply a potential difference between a first detection surface and a second detection surface. 54. A charged particle beam apparatus according to any one of the clauses, further comprising an acceleration unit configured to apply a potential difference between a first detection surface and a third detection surface. 55. A charged particle detection unit configured to assign an electrical signal generated by a first detection surface and an electrical signal generated by a second detection surface to a single charged particle count, wherein the assignment is made in response to a determination that the sum of the energies of the first and second electrical signals received within a given time frame matches a predicted energy of a secondary or backscattered particle generated by the sample. A charged particle beam apparatus as described in any one of clauses 42 to 54, further comprising: 56. A charged particle beam apparatus as described in Clause 55, wherein a given time frame is equal to the pixel residence time of the charged particle beam on the sample. 57. A charged particle beam apparatus as described in any one of clauses 42 to 56, wherein the first detector is a semiconductor-based detector. 58. A charged particle beam apparatus as described in any one of clauses 42 to 57, wherein the second detector is a semiconductor-based detector. 59. A charged particle beam apparatus as described in any one of clauses 42 to 58, wherein the first detector and / or the second detector contains germanium. 60. A charged particle beam apparatus according to any one of the clauses 42 to 59, wherein the first detection surface and / or the second detection surface is made of silicon. 61. A charged particle beam apparatus as described in any one of Clauses 42 to 60, configured to guide multiple charged particle beams into a sample and including an array of sensing elements for each of the multiple charged particle beams. 62. A non-temporary computer-readable medium having instructions that, when executed by a computer, cause the computer to perform a method for detecting particles in a charged beam apparatus, The method is, In response to a charged particle beam being incident on the sample, one or more return particles generated by the sample are detected using a first detection surface, The process involves detecting one or more particles generated by the first detection surface, which are produced in response to a return particle entering the first detection surface, using the second detection surface, Non-temporary computer-readable media, including [specific examples of such media].

[0080]

[0091] While embodiments of the present invention may be specifically referred to in relation to electron microscopes, embodiments of the present invention may be used in other types of apparatus. Embodiments of the present invention may form part of a mask inspection apparatus, a measuring apparatus, or any apparatus for measuring or processing objects such as wafers (or other substrates) or masks (or other patterning devices).

[0081]

[0092] While specific references to the use of embodiments of the present invention in relation to sample evaluation may be made above, it will be understood that the present invention is not limited to sample evaluation and may be used in other applications, such as electron beam lithography, as the context permits.

[0082]

[0093] While specific embodiments of the present invention have been described above, it will be understood that the present invention may be implemented in ways other than those described above. The above description is illustrative and not intended to be limiting. Accordingly, it will be apparent to those skilled in the art that modifications to the described invention can be made without departing from the claims set forth below.

Claims

1. A charged particle beam apparatus configured to guide a charged particle beam onto a sample, A detection system comprising: a first detection surface configured to generate an electrical signal in response to signal particles generated by the sample in response to the charged particle beam; and a second detection surface configured to generate an electrical signal in response to incident secondary particles or backscattered particles generated by the first detection surface in response to the signal particles, the second detection surface having a second hole that allows the signal particles to pass through to the first detection surface. A charged particle beam device equipped with the following features.

2. The charged particle beam apparatus according to claim 1, wherein the field of view of the second detection surface includes the first detection surface.

3. The charged particle beam apparatus according to claim 1, wherein the first detection surface defines a first hole, allowing the charged particle beam to pass through the first hole and reach the sample surface.

4. The radial line of the first detection surface has a first angle β that is 45° or less, preferably 30° or less, and more preferably 15° or less, with respect to a plane perpendicular to the charged particle beam. １ A charged particle beam apparatus according to claim 1, which forms a [unclear].

5. The first angle β １ The charged particle beam apparatus according to claim 4, wherein the angle is 0°.

6. The radial line of the second detection surface has a second angle β that is 45° or less, preferably 30° or less, and more preferably 15° or less, with respect to a plane perpendicular to the charged particle beam. ２ A charged particle beam apparatus according to claim 1, which forms a [unclear].

7. The second angle β ２ The charged particle beam apparatus according to claim 6, wherein the angle is 0°.

8. The second detection surface is an annular detection surface, The charged particle beam apparatus according to claim 1, wherein the second detection surface is arranged to surround the charged particle beam.

9. Further including a third detection surface, The charged particle beam apparatus according to claim 6, wherein the third detection surface is an annular detection surface arranged to surround the charged particle beam.

10. The charged particle beam apparatus according to claim 1, wherein the signal particles generated by the sample in response to the charged particle beam are directed away from the axis defined by the charged beam to form a secondary beam.

11. The radial line of the first detection surface has a first angle β that is 45° or less, preferably 30° or less, and more preferably 15° or less, with respect to a plane perpendicular to the secondary beam. １ A charged particle beam apparatus according to claim 10, which forms a [unclear].

12. The first angle β １ The charged particle beam apparatus according to claim 11, wherein the angle is 0°.

13. The radial line of the second detection surface has a second angle β that is 45° or less, preferably 30° or less, and more preferably 15° or less, with respect to a plane perpendicular to the secondary beam. ２ A charged particle beam apparatus according to claim 10, which forms a [unclear].

14. The second angle β ２ The charged particle beam apparatus according to claim 13, wherein the angle is 0°.

15. A non-temporary computer-readable medium having, when executed by a computer, an instruction causing the computer to perform a method for detecting particles in a charged beam device, The aforementioned method, In response to a charged particle beam being incident on a sample, one or more return particles generated by the sample are detected using a first detection surface, One or more particles generated by the first detection surface in response to the return particles being incident on the first detection surface are detected using the second detection surface, Non-temporary computer-readable media, including [specific examples of such media].

Images