Electron Beam Inspection System and Method

Abstract

To provide a system and a method that can eliminate unnecessary crosstalk and electromagnetic interference (EMI) problems.SOLUTION: An inspection system is provided with an electron beam source configured to generate one or more primary electron beams. The inspection system is provided with an electron optical column having a pair of electron optical elements configured to direct the one or more primary electron beams onto a specimen, a scintillator substrate which is further provided with a detection assembly, and configured to collect electrons emitted from the specimen and generate optical radiation in accordance with the collected electrons, one or more light guides, one or more reflective surfaces which are configured to receive the optical radiation and direct the optical radiation along the one or more light guides, and one or more detectors configured to receive the optical radiation from the light guides.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to particle beam detection, and more specifically to high-speed detectors for secondary and backscattered electron measurement.

Background Art

[0002] By identifying and classifying defects on a semiconductor wafer with an inspection system, a defect population can be generated for the specimen. Examples of inspection systems include optical inspection systems and charged particle inspection systems such as electron beam systems. In the case of an electron beam inspection system, the characteristics of the specimen are elucidated by directing an electron beam at the specimen and collecting secondary and / or backscattered electrons emitted from the specimen with a suitably configured detector. In conventional electron beam inspection systems, silicon detectors are used for the purpose of collecting secondary and backscattered electrons.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the detection bandwidth of a silicon detector is limited by its capacitance. In addition, a silicon detector usually requires a transimpedance amplifier, which can significantly affect the signal-to-noise ratio (SNR) in a low-signal environment. Furthermore, the transimpedance amplifier is required to amplify the current from the detector and usually needs to be placed as close as possible to the detector in order to maximize the bandwidth and signal-to-noise ratio. For this purpose, the transimpedance amplifier usually needs to be placed inside the vacuum chamber of the electron beam inspection system, which may cause outgassing from circuit components. And the electrical signal from the silicon detector has to be directed a significant distance outside the vacuum chamber prior to digitization, which leads to unwanted crosstalk and electromagnetic interference (EMI) problems. Therefore, it would be desirable to provide a system and method that can eliminate disadvantages such as those described above.

Means for Solving the Problems

[0005] An electron beam inspection system is disclosed. According to various embodiments, the system can be configured to have an electron beam source configured to generate one or more primary electron beams. According to additional embodiments, the system can be configured to have an electron optical column having a set of electron optical elements, and the set of electron optical elements is configured to direct the one or more primary electron beams towards a specimen. In additional embodiments, the system is configured to have a detection assembly, and the detection assembly includes a scintillator substrate configured to collect electrons emitted from the specimen in response to the one or more primary electron beams and configured to generate optical radiation in response to the collected electrons, one or more light guides, one or more reflective surfaces configured to receive the optical radiation generated by the scintillator substrate and direct the optical radiation along the one or more light guides, and one or more detectors configured to receive the optical radiation from the light guides.

[0006] A multi-column inspection system is disclosed. According to various embodiments, the system can be configured to have an electron beam source configured to generate a primary electron beam array. In additional embodiments, the system is provided with a plurality of electron optical columns, each electron optical column having a set of electron optical elements, and the set of electron optical elements is configured to direct the primary electron beams constituting the primary electron beam array to respective locations on the specimen in an array. In additional embodiments, the system has a detection assembly, and the detection assembly includes a scintillator substrate array configured to collect electrons emitted from the specimen in response to the primary electron beam array and configured to generate optical radiation in response to the collected electrons, a plurality of light guides optically coupled to the scintillator substrate array, a plurality of reflecting surfaces configured to receive the optical radiation generated by the scintillator substrates constituting the scintillator substrate array, and a plurality of detectors optically coupled to the plurality of light guides, and each detector among the plurality of detectors is configured to receive optical radiation from a certain light guide among the plurality of light guides.

[0007] A method is disclosed. In the method according to various embodiments, one or more primary electron beams are generated by an electron beam source, the one or more primary electron beams are directed to a specimen by an electron optical column, electrons emitted from the specimen in response to the one or more primary electron beams are collected by a scintillator substrate, optical radiation is generated by the scintillator substrate in response to the collected electrons, the optical radiation is directed to a light guide by a reflecting surface, the optical radiation is directed to a detector by the light guide, provided that the detector is configured to generate one or more signals in response to the optical radiation, and one or more characteristics of the specimen are discriminated based on the one or more signals.

[0008] Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily limiting of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description, serve to explain the principles of the invention.

[0009] Those skilled in the art of this technology (so-called persons skilled in the art) will be able to better understand the numerous advantages of this disclosure by referring to the following accompanying drawings.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 6

Best Mode for Carrying Out the Invention

[0011] Hereinafter, reference will be made in detail to the subject matter depicted and disclosed in the accompanying drawings. The present disclosure is specifically illustrated and described in connection with certain embodiments and their specific features. The embodiments described in this application should be regarded as illustrative rather than limiting. It should be immediately apparent to those skilled in the art that various modifications and changes can be made to the form and details without departing from the spirit and technical scope of the present disclosure.

[0012] In some conventional electron beam inspection systems, a silicon detector is used to collect secondary and backscattered electrons. However, the detection bandwidth of the silicon detector is limited by its capacitance. In addition, a transimpedance amplifier is usually required for a silicon detector, which may significantly affect the signal-to-noise ratio (SNR) in a low-signal environment.

[0013] For example, FIG. 1 is a conceptual diagram of an electron beam inspection system 100. Specifically, the electron beam inspection system 100 depicted in FIG. 1 provides an example of an electron beam inspection system. Here, according to the considerations in this application, a short description of this electron beam inspection system 100 can provide a reference point for comparison with the advantages associated with the present disclosure.

[0014] The electron beam inspection system 100 can include an electron optical column 102 configured to direct a primary electron beam from an electron source 106 (which has an emitter 108) towards the surface of a specimen 130. The electron optical column 102 can have a plurality of electron optical elements 110. Those various electron optical elements provided in the electron optical column 102 can be arranged within a vacuum chamber 104.

[0015] Among the plurality of electron optical elements 110, although not essential, one or more extractors 112, one or more condenser lenses 114, one or more alignment deflectors 116, one or more beam limiting apertures 118, one or more detectors 120, one or more scan deflectors 122 (e.g., the upper set of scan deflectors 124 and the lower set of scan deflectors 126), and one or more objective lenses 128 can be included. It should be noted here that although Figure 1 shows a specific electron optical element configuration, this illustration is provided for illustrative purposes only and should not be construed as a limitation on the technical scope of the present disclosure.

[0016] The detector 120 (e.g., a silicon detector) can be configured to collect secondary and / or backscattered electrons emitted from the surface of the specimen in response to the primary electron beam. As previously noted in this application, in a silicon detector (e.g., the detector depicted in Figure 1), the detection bandwidth may be limited. Further, in an inspection system that uses a silicon detector, such as the electron beam inspection system 100 depicted in Figure 1, a transimpedance amplifier (not shown) may be required to amplify the current reaching the detector. Such a transimpedance amplifier usually has to be placed inside the vacuum chamber 104 of the electron beam inspection system 100, which may cause outgassing of circuit components. And the electrical signal from the silicon detector has to be sent a considerable distance outside the vacuum chamber 104 prior to digitization, which leads to unwanted crosstalk and electromagnetic interference (EMI) problems.

[0017] Therefore, in the embodiments of the present disclosure, a system and method are aimed at removing one or more of the disadvantages of the above-described conventional methods. In the embodiments of the present disclosure, an electron beam inspection system that uses a scintillator substrate and a light guide to detect secondary and backscattered electrons is aimed at. In additional embodiments of the present disclosure, a multi-column beam inspection system that uses a scintillator substrate array and a plurality of light guides to detect secondary and backscattered electrons is aimed at.

[0018] According to the considerations in the present application, various embodiments of the present disclosure can provide a low-noise, low-profile, high-speed detector that can be used in a charged particle (e.g., electron beam) type property elucidation system. In particular, by enabling electron detection using a scintillator substrate and a light guide, the systems and methods of the present disclosure can address many of the drawbacks of the conventional methods described above.

[0019] Figures 2A and 2B depict the conceptual configurations of electron beam inspection systems 200a and 200b that utilize a scintillator substrate 232 and a light guide 234 according to one or more embodiments of the present disclosure.

[0020] According to various embodiments, the electron beam inspection systems 200a and 200b can be configured to have an electron optical column 202 that directs a primary electron beam from an electron beam source 206 (having an emitter 208) toward the surface of a specimen 228. According to various embodiments, the electron optical column 202 can include, but is not limited to, a microelectron optical column (e.g., a miniature column), a microelectromechanical systems (MEMS) column, a scanning electron microscopy (SEM) column, and any other electron optical column known in the art.

[0021] The electron optical column 202 can have a plurality of electron optical elements 210 including, but not limited to, one or more extractors 212, one or more condenser lenses 214, one or more alignment deflectors 216, one or more beam limiting apertures 218, one or more scan deflectors 220 (e.g., an upper set of scan deflectors 222 and a lower set of scan deflectors 224), and one or more objective lenses 226. The various electron optical elements provided in the electron optical column 202 can be disposed within a vacuum chamber 204.

[0022] According to certain embodiments, the electron beam inspection systems 200a, 200b can be made to have a detection assembly 230 comprising one or more scintillator substrates 232 and one or more light guides 234, instead of a silicon detector. In various embodiments, the scintillator substrate 232 is configured to collect secondary and / or backscattered electrons emitted from the surface of the specimen 250 in response to the primary electron beam 201. The scintillator substrate 232 can be further configured to generate optical radiation (e.g., light) in response to the collected secondary / backscattered electrons. The light guide 234, which is in the subsequent stage and forms part of the detection assembly 230, can be configured to receive the optical radiation generated by the scintillator substrate 232 and direct the optical radiation towards one or more detectors (not shown in FIGS. 2A and 2B). According to various embodiments, the light guide 234 can be configured to send the optical radiation generated by the scintillator substrate 232 to the detector via one or more vacuum feedthrough ports 236 arranged within the vacuum chamber 204.

[0023] In view of the discussion in this application, the electron beam inspection systems 200a, 200b depicted in FIGS. 2A and 2B can perform low-noise, low-profile, high-speed detection of secondary and / or backscattered electrons. By using the high-speed scintillator substrate 232 and the light guide 234, signals derived from secondary electrons and backscattered electrons can be sent outside the vacuum chamber 204 with low loss, high gain (e.g., 1 M times) and low added noise and delivered to a detector (e.g., a photomultiplier tube (PMT)). Further, by using the high-speed scintillator substrate 232 and the light guide 234, the detection assembly 230 can be made thinner and the column length can be shortened (e.g., made low-profile). In this case, the column length can be made less than 75 mm.

[0024] According to further considerations in the present application, one or more drawbacks of the electron beam inspection system 100 depicted in FIG. 1 can be eliminated by the electron beam inspection systems 200a, 200b depicted in FIGS. 2A and 2B. In particular, the detector provided in the electron beam inspection system 200 can be mounted outside the vacuum chamber 204 instead of inside the vacuum chamber 104 of the electron beam inspection system 100. By making it possible to mount the detector outside the vacuum chamber 204, spatial constraints are relaxed and the need for vacuum-compatible materials can be eliminated. In addition, noise and crosstalk can be reduced by optical transmission (instead of electrical signal transmission in FIG. 1) in FIGS. 2A and 2B. Furthermore, in the electron beam inspection systems 200a, 200b depicted in FIGS. 2A and 2B, since the need to arrange an amplifier inside the vacuum chamber 204 is eliminated, a potentially unnecessary outgassing effect can be eliminated.

[0025] In FIG. 2A, the detector assembly 230 (scintillator substrate 232 and light guide 234) is shown at a position about halfway up the column, but this should not be regarded as a limiting matter of the present disclosure unless otherwise noted in the present application. In this regard, the detector assembly 230 may be arranged at any position within the electron optical column 202 that is known in the art of the present case. For example, as detailed in the present application, the scintillator substrate 232 provided in the detection assembly 230 can be arranged around and / or in the vicinity of the optical axis of the electron optical column 202. Also for example, as shown in FIG. 2B, the detector assembly 230 (scintillator substrate and light guide) may be arranged outside the vacuum chamber 204 and outside the electron optical column 202 (e.g., below the electron optical column 202).

[0026] It should be noted here that FIGS. 2A and 2B show the specific configuration of the electron optical element 210, but this illustration is presented for illustrative purposes only and is not to be construed as limiting the technical scope of the present disclosure. The electron optical element 210 may have any configuration suitable for directing the primary electron beam towards the surface of the specimen.

[0027] The electron beam inspection systems 200a and 200b can be further illustrated and described with reference to the electron inspection system 200 depicted in FIG. 3.

[0028] FIG. 3 is a conceptual diagram of an electron beam inspection system 200 that utilizes a scintillator substrate 232 and a light guide 234 according to one or more embodiments of the present disclosure. It should be noted here that any discussion regarding the electron beam inspection systems 200a and 200b depicted in FIGS. 2A and 2B can be considered applicable to the electron beam inspection system 200 depicted in FIG. 3 unless otherwise noted in the present application. Conversely, any discussion regarding the electron beam inspection system 200 depicted in FIG. 3 can be considered applicable to the electron beam inspection systems 200a and 200b depicted in FIGS. 2A and 2B unless otherwise noted in the present application.

[0029] According to various embodiments, the electron beam inspection system 200 can include, but is not limited to, one or more electron beam sources 206, one or more electron optical columns 202, a detection assembly 232, and a controller 242 having one or more processors 244 and a memory 246. According to various embodiments, the detection assembly 230 can include, but is not limited to, one or more scintillator substrates 232, one or more light guides 234, and one or more detectors 240.

[0030] In one embodiment, the electron beam inspection system 200 is configured to inspect and / or measure a specimen 250 disposed on a stage assembly 252. In this case, the electron beam inspection system 200 can be configured to acquire one or more images of the specimen 250. In one embodiment, an electron beam source 206 is configured to generate one or more primary electron beams 201 and direct the one or more primary electron beams 201 towards the specimen 250. The electron beam source 206 can include, but is not limited to, an electron gun, a photocathode electron beam source, and any other electron beam source known in the art. It should be further noted here that the embodiments of the present disclosure can also be implemented in contexts other than electron beams and electron beam sources. In that case, the system 200 can be configured to have any type of particle beam source known in the art, including, but not limited to, an ion gun, a cathode beam source, an emitter chip, an anode, etc.

[0031] According to embodiments, the electron optical column 202 can be configured to have one or more electron optical elements 254 configured to receive one or more primary electron beams 201 and focus and / or direct the one or more primary electron beams 201 towards the specimen 250. The one or more electron optical elements 254 can include, but are not limited to, an extractor, a beam limiting aperture, a deflector, an electron optical lens, a condenser lens (e.g., a magnetic condenser lens), an objective lens (e.g., a magnetic condenser lens), and any other electron optical element known in the art. Also, for example, the electron beam inspection system 200 (e.g., the electron optical element 254) can be configured to have one or more electron beam scanning elements, including, but not limited to, one or more electromagnetic scanning coils or electrostatic deflectors suitable for controlling the position of one or more primary electron beams 201 relative to the surface of the specimen 250. Further, the one or more scanning elements can be utilized to scan the specimen 250 with one or more primary electron beams 201 according to a specified pattern.

[0032] In various embodiments, the electron beam source 206 and / or the electron optical column 202 (e.g., electron optical element 254) are configured to direct one or more primary electron beams 201 onto the surface of the specimen 250 through one or more shields 256. The specimen 250 can include, but is not limited to, wafers, reticles, photomasks, and any other specimen known in the art. In one embodiment, the specimen 250 is disposed on a stage assembly 252 to facilitate movement of the specimen 250. In one embodiment, the stage assembly 252 is a drivable stage. For example, the stage assembly 252 can include one or more translation stages suitable for selectively translating the specimen 250 along one or more linear directions (e.g., the x, y, and / or z directions), but is not limited thereto. For example, the stage assembly 252 can include one or more rotation stages suitable for selectively rotating the specimen 250 along a certain rotation direction, but is not limited thereto. For example, the stage assembly 252 can include rotation stages and translation stages suitable for selectively rotating the specimen 250 along a rotation direction and / or selectively translating the specimen 250 along a linear direction, but is not limited thereto. It should be noted here that the electron beam inspection system 200 can operate in any scanning mode known in the art.

[0033] In various embodiments, the electron optical inspection system 200 is provided with a detection assembly 230 configured to collect secondary and / or backscattered electrons 203 (hereinafter simply referred to as "secondary electrons 203") emitted from the surface of the specimen 250 in response to one or more primary electron beams 201. According to various embodiments, the detection assembly 230 can include, but is not limited to, one or more scintillator substrates 232, one or more light guides 234, and one or more detectors 240.

[0034] In various embodiments, the scintillator substrate 232 is configured to collect secondary electrons 203 emitted from the surface of the specimen 250 in response to the primary electron beam 201. The scintillator substrate 232 can be further configured to generate optical radiation (e.g., light) in response to the collected secondary electrons 203. The scintillator substrate 232 can be made from any scintillator material known in the art, including but not limited to sapphire substrates, glass substrates, etc. The scintillator substrate 232 can exhibit various thicknesses depending on the material of the scintillator substrate 232. For example, the scintillator substrate 232 can be made to have a thickness of about 0.4 mm to 0.5 mm (e.g., the height shown in FIG. 3). According to certain embodiments, the electron optical column 202 can be made to have one or more electron optical elements 254 configured to collect secondary electrons 203 emitted from the surface of the specimen 250 and direct / focus them onto the scintillator substrate 232.

[0035] The light guide 234, which is located in the subsequent stage and constitutes the detection assembly 230, can be configured to receive the optical radiation generated by the scintillator substrate 232 and direct the optical radiation towards one or more detectors 240. As noted in the present application, according to the various embodiments of the present disclosure, while arranging various members provided in the electron beam inspection system 200 (e.g., the electron beam source 206, the scintillator substrate 232, the light guide 234) within the vacuum chamber 204, the detector 240 can be arranged outside the vacuum chamber 204 of the electron beam inspection system 200. In that case, according to certain embodiments, the light guide 234 can be configured to transmit the optical radiation generated by the scintillator substrate 232 to the detector 240 through one or more vacuum feedthrough ports 236 arranged within the vacuum chamber 204.

[0036] According to the considerations in this application, the light guide 234 can be configured to collect and direct the optical radiation (e.g., light) generated by one or more scintillator substrates 232, and can have any optical member known in the technical field of this case. For example, the light guide 234 can have one or more optical fibers. As an example, the light guide 234 can have an optical fiber bundle. Also, for example, the light guide 234 can have a solid light guiding material (e.g., a light tube, an optical waveguide, etc.).

[0037] Also, in certain embodiments, the detection assembly 230 is configured to have one or more reflective surfaces and / or refractive surfaces that collect light and direct it (e.g., couple it) towards the detector 240. For example, the light guide 234 provided in the detection assembly 230 can have a reflective surface 238 configured to form an angle with the surface of the scintillator substrate 232, and the reflective surface 238 can be configured to direct the optical radiation (light) from the scintillator substrate 232 towards the detector 240. For example, the reflective surface 238 can be configured to form an angle of 35 to 55 degrees. The reflective surface 238 can be a mirror surface, a metal-coated surface, etc. For example, the reflective surface 238 may have an aluminum coating. Also, for example, one or more ends of the light guide 234 can have a reflective surface 238 configured to form an angle with the surface of the scintillator substrate 232.

[0038] According to certain embodiments, the detection assembly 230 can further have one or more refractive index matching materials configured to facilitate the coupling of optical radiation with the outside of the vacuum chamber 204. For example, the detection assembly 230 can have one or more refractive index matching materials arranged at the interface between the scintillator substrate 232 and one or more light guides 234 to facilitate the collection and transmission of the optical radiation generated by the scintillator substrate 232.

[0039] According to additional and / or alternative embodiments, the detection assembly 230 can further include one or more micro-optical elements configured to facilitate the transmission of optical radiation from the scintillator substrate 232. For example, the detection assembly 230 can include one or more micro-optical elements configured to focus at least a portion of the optical radiation generated by the scintillator substrate 232 onto at least a portion of the light guide 234. For example, in the case of an optical fiber bundle, the use of micro-optical elements can focus portions of the optical radiation generated at specific locations on the scintillator substrate 232 onto specific optical fibers that make up the optical fiber bundle. The micro-optical elements in this example can be disposed between the scintillator substrate 232 and the light guide 234 (e.g., that disposed on the surface of the scintillator substrate 232). It is noted here that by adding micro-optical elements into the detection assembly 230, the spatial resolution of the generated optical radiation on one or more detectors 240 can be improved. The one or more micro-optical elements can include, but are not limited to, lenses, mirrors, prisms, beam splitters, and any other micro-optical elements known in the art. For example, the one or more micro-optical elements can include, but are not limited to, a microlens array, one or more diffractive optical elements (DOEs), one or more refractive optical elements (ROEs), one or more homogenizers, etc.

[0040] According to various embodiments, one or more detectors 240 can be configured to receive the optical radiation (e.g., light) transmitted by the light guide 234. The detector 240 can include, but is not limited to, a multi-channel or single-channel detector, and is configured to detect the optical radiation generated by the scintillator substrate 232, and can include any detector known in the art. For example, the detector 240 can include, but is not limited to, a charge-coupled device (CCD), a complementary metal-oxide semiconductor (CMOS) device, a photomultiplier tube (PMT), a photodiode array, an avalanche photodiode detector (APD), an imaging device, etc. In various embodiments, the detector 240 is configured to receive the optical radiation and generate a signal and / or an image based on the received optical radiation. In various embodiments, the one or more detectors 240 are configured to generate one or more signals (e.g., detector signals) and / or one or more images in response to the optical radiation received through the light guide 234.

[0041] The electron beam inspection system 200 can further include a controller 242 communicatively coupled to the detector 240 and / or communicatively coupled to various components of the electron beam inspection system 200 itself (e.g., electron beam source 206, electron optical element 254, stage assembly 252, etc.). The controller 242 can be configured to have one or more processors 244 configured to execute a set of program instructions stored in the memory 246, and the set of program instructions can be configured to cause the one or more processors 244 to execute various steps / functions of the present disclosure. For example, the controller 242 can be configured to analyze the output of the detector 240 (e.g., analyze an image / detector signal). Also, in certain embodiments, the controller 242 is configured to analyze one or more characteristics of the specimen 250 based on the detector signal received from the detector 240. Also, in certain embodiments, the controller 242 is configured to modify one or more characteristics of the electron beam inspection system 200 to continuously focus on the specimen 250. For example, the one or more processors 244 can be configured to adjust one or more characteristics of the electron beam source 206 and / or other elements provided in the electron beam inspection system 200 to focus the primary electron beam 201 on the surface of the specimen 250. Also, for example, the controller 242 can be configured to independently adjust the position or alignment of one or more primary electron beams 201 and scan the specimen 250 with the primary electron beam 201 by adjusting one or more focus voltages applied to one or more electron optical elements 254.

[0042] According to additional embodiments, the controller 242 can be configured to receive a detector signal and / or an image generated by one or more detectors 240 in response to received optical radiation. The controller 242 can be configured to store the received detector signal and / or image in the memory 246. According to embodiments, the controller 242 can further be configured to determine one or more characteristics of the specimen 250 based on the received detector signal and / or image. Among the characteristics of the specimen 250, those that can be determined by the controller 242 based on the signal / image received from the detector 240 include, but are not limited to, measurement results for the specimen 250 (e.g., measurement results for critical dimensions (CD)), the presence or absence of defects on the specimen 250, defect positions, defect sizes, and the like. The characteristic determination results can be stored in the memory 246.

[0043] According to additional and / or alternative embodiments, the controller 242 can be configured to generate one or more control signals configured to selectively adjust one or more characteristics of one or more process tools based on one or more determined characteristics of the specimen 250. In this case, the controller 242 can be configured to generate one or more control signals within a feedforward or feedback loop to selectively adjust upstream and / or downstream process tools. Among the process tools, those that can be adjusted based on the determined characteristics of the specimen 250 include, but are not limited to, lithography tools, etching tools, polishing tools, deposition tools, and the like.

[0044] Also, in certain embodiments, as shown in FIG. 3, the electron beam inspection system 200 is assumed to have a user interface 248 communicatively coupled to the controller 242. Also, in certain embodiments, the user interface 248 is assumed to have a user input device and a display. The user input device provided in the user interface 248 can be configured to receive one or more input commands from the user, and the one or more input commands can be configured to input data into the electron beam inspection system 200 and / or adjust one or more characteristics of the electron beam inspection system 200. Also, according to certain embodiments, the display provided in the user interface 248 can be configured to display data of the electron beam inspection system 200 to the user.

[0045] It should be noted that the electron beam inspection system 200 is not limited to the electron optical elements described in FIGS. 2A, 2B, and 3, and those electron optical elements are merely presented for illustrative purposes. It should be further noted that the electron beam inspection system 200 can have any number and types of electron optical elements necessary to direct / focus one or more primary electron beams 201 onto the specimen 250 and collect and image the secondary and / or backscattered electrons 203 emitted in response thereon onto the scintillator substrate 232.

[0046] FIG. 4A is a schematic diagram of a scintillator substrate 232 provided in the electron beam inspection system 200 according to one or more embodiments of the present disclosure.

[0047] Referring to FIG. 3, as per the present application's existing order, the electron beam source 206 and / or the electron optical element 254 can be configured to direct one or more primary electron beams 201 through the shield 256 towards the active area 260 of the scintillator substrate 232. According to certain embodiments, the shield 256 can be made to have an inner diameter 258 on the order of 50 - 100 μm (as shown in FIG. 3) to transmit the primary electron beam 201. The active area 260 of the scintillator substrate 232 can be made to have a diameter on the order of 4 - 5 mm, with a dead area 262 outside the active area 260 extending to the edge of the scintillator substrate 232. This scintillator substrate 232 can be made to have a diameter on the order of 8 - 9 mm. It should be noted here that these dimensions are merely illustrative and are not to be construed as limiting the technical scope of the present disclosure. The dimensions can be selected to match the geometry and dimensions of the electron optical column.

[0048] FIG. 4B is a schematic diagram of a scintillator substrate 232 provided in an electron beam inspection system 200 according to one or more embodiments of the present disclosure.

[0049] According to certain embodiments, one or more scintillator substrates 232 can be divided into a plurality of regions 264a-264d. According to the considerations in this application, by dividing the scintillator substrate 232 into two or more regions, a high level of spatial resolution can be provided on the scintillator substrate 232 and / or the detector 240. For example, as shown in FIG. 4B, the scintillator substrate 232 can be divided into four individual regions (e.g., four individual quadrants), namely a first region 264a, a second region 264b, a third region 264c, and a fourth region 264d. According to the considerations in this application, the individual regions 264a-264d of the scintillator substrate 232 may or may not be physically spatially separated from each other. For example, the scintillator substrate 232 may be solely nominally divided into a plurality of regions 264a-264d, and the scintillator substrate 232 may still constitute a single cohesive continuous scintillator substrate 232. Also for example, the scintillator substrate 232 may be physically and spatially divided into a plurality of regions 264a-264d, and each region 264a-264d of the scintillator substrate 232 may be separated from the adjacent regions 264a-264d by a certain space or gap.

[0050] According to certain embodiments, each of the individual regions 264a-264d of the scintillator substrate 232 can be coupled to a single detector 240 via an individual light guide, and the detector 240 can be made capable of spatial resolution and capable of discriminating which optical radiation is emitted from which individual region 264a-264d. Therefore, according to the recognition in this application, by dividing one or more scintillator substrates 232 into individual regions 264a-264n, the spatial resolution (e.g., angular distribution) of the scintillator substrate 232 and / or the detector 240 can be improved, and the specimen 250 can be characterized more accurately by the electron beam inspection system 200.

[0051] Although the scintillator substrate 232 in FIG. 4B is illustrated and described as being divided into four individual quadrants, this should not be construed as a limitation of the present disclosure unless otherwise noted herein. In this regard, the scintillator substrate 232 can be divided into any number, shape, and / or configuration of regions 264a to 264n known in the art of the present case.

[0052] FIG. 5A is a schematic diagram of a scintillator substrate array 268 provided in a multi-column inspection system 200 according to one or more embodiments of the present disclosure.

[0053] According to certain embodiments, the electron beam inspection system 200 can include a multi-column inspection system 200 configured to generate an array of primary electron beams 201. For example, the electron beam inspection system 200 can be provided with one or more electron beam sources 206 configured to generate an array of primary electron beams 201a to 201n with a plurality of electron optical columns 202a to 202n. In this example, each of the electron optical columns 202a to 202n can be configured to direct a certain primary electron beam 201 out of the plurality of primary electron beams 201a to 201n towards the specimen 250.

[0054] For example, as shown in FIG. 5A, the electron beam inspection system 200 can be configured to have a plurality of electron optical columns 202a to 202n arranged in a 4×4 array. Each of the electron optical columns 202a to 202n can be configured to direct primary electron beams 201a to 201n to respective locations / places on the specimen 250 that form an array. According to this example, the electron beam inspection system 200 can be configured to have an array of scintillator substrates 232a to 232n configured to collect secondary electrons 203 emitted from an array of respective locations on the specimen 250 in response to the plurality of primary electron beams 201a to 201n. In this case, the electron beam inspection system 200 can be arranged according to a multi-column configuration (e.g., 4×4 column configuration). As can be observed here, the plurality of electron optical columns 202a to 202n provided in the electron beam inspection system 200 can be configured to have any number, arrangement, or configuration of columns known in the technical field of the present case. The arrangement of those columns is not limited to a square array, for example, a 4×4 one. Those columns may be arranged in the form of a rectangular array (e.g., a form of an array having different numbers of columns along the x-direction and the y-direction), a single row form, a two-row form, or other configurations.

[0055] FIG. 5B is a conceptual diagram of the scintillator substrate array 268 in the multi-column inspection system 200 according to one or more embodiments of the present disclosure.

[0056] According to certain embodiments, each electron optical column 202a - 202b of the multi-column electron beam inspection system 200 can be provided with a separate detection assembly 230. For example, as shown in FIG. 5B, the electron beam inspection system 200 can be configured to have a first electron optical column 202a, a second electron optical column 202b, a third electron optical column 202c, and an nth electron optical column 202n. Each electron optical column 202a - 202n can be configured to direct primary electron beams 201a - 201n towards a specimen 250 (and / or multiple specimens 250a - 250n). Further, each electron optical column 202a - 202n can be provided with individual scintillator substrates 232a - 232n configured to collect secondary electrons 203. According to this example, the first scintillator substrate 232a provided in the first electron optical column 202a can be coupled to a first light guide 234a and a first detector 240a. Similarly, the second scintillator substrate 232b provided in the second electron optical column 202b can be coupled to a second light guide 234b and a second detector 240b, the third scintillator substrate 232c provided in the third electron optical column 202c can be coupled to a third light guide 234c and a third detector 240c, and the nth scintillator substrate 232n provided in the nth electron optical column 202n can be coupled to an nth light guide 234n and an nth detector 240n.

[0057] In certain embodiments, one or more of the scintillator substrates 232 described in FIGS. 5A and 5B are segmented into two or more segments as shown in FIG. 4B. Here, the discussion regarding the segmentation of the scintillator substrate 232 shown in FIG. 4B should be understood to extend to the embodiments of FIGS. 5A and 5B. When the segmented substrate 232 is incorporated into the array 268 described in FIGS. 5A and 5B, each region of those segmented scintillator substrates 232 can be optically coupled to one or more detectors 240 via separate light guides 234. According to this configuration, various regions of the scintillator substrate 232 can be optically coupled to the detector array. For example, with respect to the scintillator substrate 232 depicted in FIG. 4B and the scintillator substrate array 268 in FIGS. 5A and 5B, the first region 264a of the scintillator substrate 232 can be coupled to the first detector 240a via the first light guide 234a. Similarly, the second region 264b of the scintillator substrate 232 can be coupled to the second detector 240b via the second light guide 234b, the third region 264c of the scintillator substrate 232 can be coupled to the third detector 240c via the third light guide 234c, and the fourth region 264d of the scintillator substrate 232 can be coupled to the fourth detector 240d via the fourth light guide 234d. According to this example, each of the individual light guides 234a - 234n can be made to have a separate set of micro - optical elements (e.g., the first set of micro - optical elements, the second set of micro - optical elements, the third set of micro - optical elements, and the fourth set of micro - optical elements) configured to focus the optical radiation generated by each of the individual regions 264a - 264d onto the corresponding light guide.

[0058] For example, each of the individual regions 264a to 264d of the scintillator substrate 232 can be coupled to a single detector 240 via an individual light guide, and the detector 240 can be made capable of spatial resolution and determining which optical radiation is emitted from which individual region 264a to 264d. Therefore, according to the recognition in the present application, by dividing one or more scintillator substrates 232 into individual regions 264a to 264n, it is possible to improve the spatial resolution (e.g., angular distribution) of the scintillator substrate 232 and / or the detector 240, and it is also possible to more accurately characterize the specimen 250 by the electron beam inspection system 200.

[0059] It should be noted here that one or more members provided in the electron beam inspection system 200 may be communicatively coupled to various other members provided in the electron beam inspection system 200 in any manner known in the art. For example, one or more processors 244 may be communicatively coupled to each other and to other components of the electron beam inspection system 200 via a wired connection (e.g., copper wire, optical fiber cable, etc.) or a wireless connection (e.g., RF coupling, IR coupling, data network communication, WiFi (registered trademark), WiMax (registered trademark), Bluetooth (registered trademark), 3G, 4G, 4G LTE, 5G, etc.).

[0060] According to one embodiment, one or more of the processors 244 can include any one or more processing elements known in the art. In that sense, one or more of the processors 244 can include any microprocessor-type device configured to execute software algorithms and / or instruction sets. According to one embodiment, one or more of the processors 244 can be a desktop computer, a mainframe computer system, a workstation, an image computer, a parallel processor, or other computer system (e.g., a network-connected computer) configured to execute a program configured to operate the electron beam inspection system 200 as described throughout this disclosure. It should be appreciated that the various steps described throughout this disclosure may be performed by a single computer system or, alternatively, by a plurality of computer systems. In general, the term "processor" can be defined broadly to include any device having one or more processing elements that execute program instructions obtained from a memory 246. Additionally, separate subsystems provided in the electron beam inspection system 200 (e.g., electron beam source 206, electron optical column 202, detector 240, controller 242, user interface 248) may incorporate a processor or logic element suitable for performing at least a portion of the various steps described throughout this disclosure. Accordingly, the foregoing description should be construed as illustrative rather than as a limitation on this disclosure.

[0061] The memory 246 can include any storage medium known in the art suitable for storing program instruction groups executable by one or more associated processors 244 and / or images received from the detector 240. For example, the memory 246 can include a non-transitory storage medium. For example, the memory 246 can include, but is not limited to, a read-only memory (ROM), a random access memory (RAM), a magnetic or optical storage device (e.g., disk), a magnetic tape, a solid state drive, etc. Further noted is that the memory 246 can be housed within a common controller housing together with one or more processors 244. According to an alternative embodiment, the memory 246 can be remotely located with respect to the physical locations of the processor 244, the controller 242, etc. Also, in some embodiments, a program instruction group for causing one or more processors 244 to execute the various steps described throughout the present disclosure is held by the memory 246.

[0062] In some embodiments, a user interface 248 is communicatively coupled to the controller 242. According to some embodiments, the user interface 248 can include, but is not limited to, one or more desktops, tablets, smartphones, smartwatches (registered trademark), etc. Also, in some embodiments, the user interface 248 is assumed to have a display, and data of the electron beam inspection system 200 is displayed for the user using the same. The display of the user interface 248 can include any display known in the art. For example, the display can include, but is not limited to, a liquid crystal display (LCD), an organic light emitting diode (OLED) type display, or a CRT display. It should be recognized by those of ordinary skill in the art that all display devices that can be integrated with the user interface 248 are suitable for implementation in the present disclosure. Also, according to some embodiments, a user can input selection items and / or instructions according to the data displayed for the user via the user interface 248.

[0063] FIG. 6 depicts a flowchart of a method 600 for operating an electron beam inspection system 200 in accordance with one or more embodiments of the present disclosure. It should be noted here that the steps of method 600 can be performed in whole or in part by electron beam inspection system 200. That being said, according to further recognition, method 600 is not limited to electron beam inspection system 200, and all or some of the steps of method 600 may be performed by additional or alternative system-level embodiments.

[0064] In step 602, one or more primary electron beams are generated by an electron beam source. For example, as shown in FIG. 3, electron beam source 206 is configured to generate one or more primary electron beams 201 and direct the one or more primary electron beams 201 towards specimen 250. The electron beam source 206 may include, but is not limited to, an electron gun, a photocathode-type electron beam source, and any electron beam source known in the art of the present technology.

[0065] In step 604, the one or more primary electron beams are directed towards the specimen by an electron optical column. For example, electron optical column 202 can be configured to have one or more electron optical elements 254 that receive the one or more primary electron beams 201 and direct the one or more primary electron beams 201 towards specimen 250. The one or more electron optical elements 254 may include, but are not limited to, an extractor, a beam limiting aperture, a deflector, an electron optical lens, a condenser lens (e.g., a magnetic condenser lens), an objective lens (e.g., a magnetic condenser lens), and any electron optical element known in the art of the present technology.

[0066] In step 606, electrons emitted from the specimen in response to the one or more primary electron beams are collected by the scintillator substrate. For example, the scintillator substrate 232 is configured to collect secondary electrons 203 emitted from the surface of the specimen 250 in response to the primary electron beam 201. The scintillator substrate 232 can be made from any scintillator material known in the art, such as, but not limited to, a sapphire substrate, a glass substrate, etc.

[0067] In step 608, optical radiation is generated by the scintillator substrate in response to the collected electrons. For example, the scintillator substrate 232 can be further configured to generate optical radiation (e.g., light) in response to the collected secondary electrons 203.

[0068] In step 610, the optical radiation is directed towards the light guide using a reflective surface. According to various embodiments, the detection assembly 230 can be configured to have a reflective surface 238 that directs the optical radiation towards the entrance surface of the light guide 234. For example, the reflective surface 238 can be configured to form an angle (e.g., 35 - 55 degrees) with respect to the surface of the scintillator substrate 232.

[0069] In step 612, the optical radiation is directed towards the detector using the light guide. In various embodiments, the detector 240 is configured to generate one or more signals in response to the optical radiation. For example, the light guide 234 provided in the detection assembly 230 can be configured to receive the optical radiation generated by the scintillator substrate 232 and direct the optical radiation towards one or more detectors 240. The light guide 234 can include any optical member known in the art that is configured to collect and direct the optical radiation (e.g., light) generated by the one or more scintillator substrates 232, such as, but not limited to, one or more optical fibers, one or more bundles of optical fibers, one or more light tubes, one or more optical waveguides, etc.

[0070] In step 614, one or more characteristics of the specimen are determined based on the one or more signals. For example, the controller 242 can be further configured to determine one or more characteristics of the specimen 250 based on the received detector signal and / or image. Among the characteristics of the specimen 250, those that can be determined by the controller 242 based on the signal / image received from the detector 240 include, but are not limited to, measurement results for the specimen 250 (e.g., measurement results of critical dimension (CD)), the presence or absence of defects on the specimen 250, defect positions, defect sizes, and the like.

[0071] The various members (e.g., various operations), devices, objects, and the accompanying discussions described in the present application are used as examples to contribute to conceptual clarity, and various structural modifications are considered. Therefore, the specific examples and the accompanying discussions used and described in the present application are, by assumption, representative of their broader classification categories. Generally, the use of any specific example is, by assumption, representative of its classification category, and it should not be construed as a limitation that specific members (e.g., various operations), devices, and objects are not included.

[0072] There are various means capable of executing and / or realizing the processes and / or systems and / or other technologies described in this application (e.g., hardware, software, and / or firmware), and which means is appropriate depends on the circumstances in which the processes and / or systems and / or other technologies are utilized. For example, if the implementer determines that speed and accuracy are crucial, the implementer will primarily select hardware and / or firmware means; if flexibility is crucial instead, the implementer will primarily select a software implementation form; if neither is the case, the implementer will select some combination of hardware, software, and / or firmware. Thus, among the several potential means capable of executing and / or realizing the processes and / or devices and / or other technologies described in this application, none is inherently superior to the others, and which means to utilize is a matter of choice determined by mutable factors such as the circumstances in which the means will be reused and the specific concerns of the implementer (e.g., speed, flexibility, or predictability).

[0073] The above description has been presented so that a so-called person skilled in the art can make and use the invention as presented in accordance with the context of a particular use and its various conditions. The directional indicators used in this application, such as "top," "bottom," "above," "below," "toward the top," "upward," "toward the bottom," "downward," and "downward," are intended to present relative positions for descriptive purposes and do not intend to specify an absolute reference coordinate system. It will be apparent to a so-called person skilled in the art that various modifications can be made to the described embodiments, and the general principles defined in this application can also be applied to other embodiments. Therefore, the invention is not, as a matter of assumption, limited to the specific embodiments illustrated and described, but is associated with the broadest technical scope consistent with the principles and novel features disclosed in this application.

[0074] Regarding the use of almost all plural and / or singular terms in this application, a so-called person skilled in the art can appropriately read and convert them from plural to singular and / or from singular to plural according to the context and / or usage. For the sake of clarity, this application does not explicitly explain various singular / plural reading conversions.

[0075] Any of the methods described in this application can include storing in memory the results of one or more steps of those method embodiments. Those results can include any of the results described in this application, and the storage can be performed in any manner known in the relevant technical field. The memory can include any of the memories described in this application and any other suitable storage media known in the relevant technical field. After storing the results, access the results in the memory and use them in any of the methods or system embodiments described in this application, format them for display to the user, use them in another software module, method, or system, etc. Furthermore, the result storage can be "permanent", "semi-permanent", "temporary", or over a certain period. For example, the memory can be a random access memory (RAM), and the results may not necessarily exist permanently in the memory.

[0076] According to further considerations, each embodiment of the above-described method can incorporate any other steps (groups) of any other method (group) described in this application. In addition, each embodiment of the above-described method can be executed by any of the systems described in this application.

[0077] The subject matter described in the present application sometimes takes a state in which components are incorporated into other components or connected / linked to other components. Such illustrated configurations are merely examples, and in fact, many other configurations can be implemented to achieve the same function. Conceptually, in any component arrangement that can achieve the same function, those components are effectively "cooperating" so that their desired function is achieved. Therefore, any two components in the present application that are combined to achieve a specific function can be regarded as "cooperating" with each other so that their desired function is achieved, regardless of the configuration or intervening components. Similarly, any two components that are cooperating in such a way can also be seen as "connected / linked" or "coupled" to each other to achieve their desired function, and any two components that can be made to cooperate in such a way can also be seen as "couplable" to each other to achieve their desired function. Specific examples of couplable include, but are not limited to, components being physically fittable and / or physically interacting with each other, and / or components being wirelessly interactable and / or wirelessly interacting with each other, and / or components being logically interactable and / or logically interacting with each other.

[0078] The present invention is further defined by the appended claims. Generally, the terms used in this application, particularly in the appended claims (e.g., the body of the appended claims), are generally intended to be "open" (e.g., the term "comprising" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "including" should be interpreted as "including but not limited to," etc.). If a specific number of claim-introducing features is intended, that intention will be clearly stated in the claim, and the absence of such features indicates no intention. For example, as an aid to understanding, some of the appended claims below incorporate claim-introducing features through the use of the introductory phrases "at least one" and "one or more." However, the use of the indefinite article "a" or "an" should not be construed as implying that the introduction of a claim feature with the indefinite article "a" or "an" implies that all individual claims containing that claim feature are limited to inventions containing only one of that feature, even when the indefinite article "a" or "an" coexists with the indefinite article in the very same claim (e.g., "a" and / or "an" should generally be interpreted as meaning "at least one" or "one or more"). The same is true for the introduction of claim features with the definite article. In addition, even when a specific number of a claim feature is specified, the number should generally be interpreted as meaning at least that specified number (e.g., the bare phrase "two features" without any other modifier generally means at least two features or more than two features). Furthermore, in instances where a convention similar to "at least one of A, B, and C, etc." is used, the intent of such syntax generally follows the sense in which one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include, but is not limited to, a system having only A, only B, only C, both A and B, both A and C, both B and C, and / or all three of A, B, and C, etc.).In an example where a convention similar to “at least one of A, B, or C, etc.” is used, generally, the intention of such syntax follows the sense in which a so-called person skilled in the art would understand the convention (e.g., for “a system having at least one of A, B, or C,” although not limited to this, a system having only A, only B, only C, both A and B, both A and C, both B and C, and / or all three of A, B, and C, etc. would be included). Almost all disjunctive conjunctions and / or disjunctive clauses presenting two or more alternative words, regardless of where they are in the specification, claims, and drawings, should be understood as considering the possibility of including one word, any word, or both words. For example, the phrase “A or B” would be understood to include the possibilities of “A” or “B” or “A and B.”

[0079] Many of the present disclosure and its attendant advantages will be understood from the foregoing description, and it will also be apparent that various modifications can be made to the form, construction, and arrangement of the various components without departing from the disclosed subject matter or sacrificing all of its main advantages. The forms described are for illustrative purposes only, and the intention of the claims set forth hereinafter is to cover, include such modifications. Further, it is the claims in a separate section that define the present invention.

Claims

1. A multi-column inspection system, comprising: an electron beam source configured to generate a primary electron beam array; a plurality of electron optical columns, each electron optical column having a set of electron optical elements configured to direct a respective primary electron beam of the primary electron beam array to respective locations on a specimen to form an array, the plurality of electron optical columns including columns having a plurality of micro electron optical elements in their configuration; a detection assembly, the detection assembly comprising: a scintillator substrate array configured to collect electrons emitted from the specimen in response to the primary electron beam array and configured to generate optical radiation in response to the collected electrons; a plurality of light guides optically coupled to the scintillator substrate array; a plurality of reflecting surfaces configured to receive the optical radiation generated by a respective scintillator substrate of the scintillator substrate array; a plurality of detectors optically coupled to the plurality of light guides, each detector of the plurality of detectors being configured to receive the optical radiation from a respective light guide of the plurality of light guides; A multi-column inspection system comprising the above.

2. The multi-column inspection system according to claim 1, further comprising a controller communicatively coupled to the plurality of detectors, the controller having one or more processors configured to execute a set of program instructions stored in a memory, the set of program instructions causing the one or more processors to: receive one or more signals generated by the plurality of detectors in response to the optical radiation; and discriminate one or more characteristics of the specimen based on the one or more signals. A multi-column inspection system configured as above.

3. The multi-column inspection system according to claim 1, wherein the specimen and the scintillator substrate array are disposed within a vacuum chamber, and the plurality of detectors are disposed outside the vacuum chamber.

4. The multi-column inspection system according to claim 3, wherein the plurality of light guides are configured to direct the optical radiation generated by the scintillator substrate array to the plurality of detectors through at least one vacuum feed-through port in the vacuum chamber.

5. The multi-column inspection system according to claim 1, wherein the detection assembly further comprises one or more refractive index matching materials disposed at the interface between the scintillator substrate array and the plurality of light guides.

6. The multi-column inspection system according to claim 1, wherein a certain one of the plurality of light guides is provided with one or more optical fibers forming a bundle.

7. The multi-column inspection system according to claim 6, wherein a certain one of the plurality of light guides further comprises one or more micro-optical elements configured to focus at least a portion of the optical radiation generated by the scintillator substrate onto at least a portion of the one or more optical fibers forming the bundle.

8. The multi-column inspection system according to claim 1, wherein the plurality of detectors include at least one of a charge-coupled device (CCD), a complementary metal-oxide semiconductor (CMOS) device, a photomultiplier tube (PMT), an avalanche photodiode (APD), and a photodiode array.

9. The multi-column inspection system according to claim 1, wherein at least one scintillator substrate of the scintillator substrate array is divided into a first region and at least one additional region.

10. The multi-column inspection system according to claim 9, wherein at least one of the plurality of light guides is a first light guide configured to receive the optical radiation generated by the first region of the scintillator substrate and direct the optical radiation to a first detector, and at least one additional light guide configured to receive the optical radiation generated by the at least one additional region of the scintillator substrate and direct the optical radiation to at least one additional detector.

11. The multi-column inspection system according to claim 10, wherein the first light guide has a first set of micro-optical elements configured to focus the optical radiation generated by the first region of the scintillator substrate; the at least one additional light guide has at least one additional set of micro-optical elements configured to focus the optical radiation generated by the at least one additional region of the scintillator substrate; A multi-column inspection system.

12. The multi-column inspection system according to claim 1, wherein the plurality of reflecting surfaces are configured to form an angle with respect to the surface of the scintillator substrate array.

13. The multi-column inspection system according to claim 12, wherein the angle of the reflecting surface is 35 to 55 degrees.

14. Generate a primary electron beam array with an electron beam source, each of the plurality of electron optical columns has a set of electron optical elements, and the set of electron optical elements direct a certain primary electron beam in the primary electron beam array to various locations forming an array on the specimen, and the plurality of electron optical columns have columns having a plurality of micro electron optical elements in the configuration; collect electrons emitted from the specimen according to the primary electron beam array by a scintillator substrate array of a detection assembly, and generate optical radiation according to the collected electrons; receive the generated optical radiation with a plurality of reflecting surfaces; receive the optical radiation by each of a plurality of detectors optically coupled to a plurality of light guides optically coupled to the scintillator substrate array; A method.

15. The method according to claim 14, further comprising receiving one or more signals generated by the plurality of detectors according to the optical radiation; discriminating one or more characteristics of the specimen based on the one or more signals; A method.

16. The method according to claim 14, wherein the specimen and the scintillator substrate array are arranged in a vacuum chamber, and the plurality of detectors are arranged outside the vacuum chamber; A method.

17. The method according to claim 16, wherein The plurality of light guides direct the optical radiation generated by the scintillator substrate array to the plurality of detectors via at least one vacuum feedthrough port in the vacuum chamber. Method. A method according to claim 18, wherein the detection assembly further comprises one or more refractive index matching materials disposed at the interface between the scintillator substrate array and the plurality of light guides. Method. A method according to claim 19, wherein a certain light guide among the plurality of light guides is provided with one or more optical fibers forming a bundle. Method. A method according to claim 20, wherein a certain light guide among the plurality of light guides focuses at least a portion of the optical radiation generated by the scintillator substrate onto at least a portion of one or more optical fibers forming the bundle by one or more micro-optical elements. Method. A method according to claim 21, wherein the plurality of detectors includes at least one of a charge-coupled device (CCD), a complementary metal-oxide semiconductor (CMOS) device, a photomultiplier tube (PMT), an avalanche photodiode (APD), and a photodiode array. Method. A method according to claim 22, wherein at least one scintillator substrate of the scintillator substrate array is divided into a first region and at least one additional region. Method. A method according to claim 23, wherein at least one light guide among the plurality of light guides a first light guide configured to receive the optical radiation generated by the first region of the scintillator substrate and direct the optical radiation to a first detector; at least one additional light guide configured to receive the optical radiation generated by the at least one additional region of the scintillator substrate and direct the optical radiation to at least one additional detector. including Method. A method according to claim 24, wherein the first set of micro-optical elements of the first light guide focuses the optical radiation generated by the first region of the scintillator substrate; the additional set of micro-optical elements of the at least one additional light guide focuses the optical radiation generated by the at least one additional region of the scintillator substrate. Method. **Claim 25**: The method according to claim 14, wherein the plurality of reflecting surfaces are configured to form an angle with respect to the surface of the scintillator substrate array, the method. **Claim 26**: The method according to claim 25, wherein the angle of the reflecting surface is 35 to 55 degrees, the method.

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