Charged-particle optical module

Abstract

A charged particle optical module (200) for a plurality of charged particle optical apparatuses configured to direct a charged particle beam along a respective beam path towards a sample position, the charged particle optical module comprising: at least one emitter (21) arranged at an emission surface (80) of an emitter layer, each emitter configured to emit charged particles for a source beam; at least one extractor electrode (27) for the at least one emitter, wherein the at least one extractor electrode is planar and defines a beam aperture for the charged particles emitted by the respective emitter in each extractor electrode; and a spacer (88) configured to space each extractor electrode from the emission surface, wherein the spacer is an electrical insulator and comprises an insulator surface (94) between the extractor electrode and the emission surface, wherein at least a portion of the insulator surface is angled with respect to a direction perpendicular to the emission surface.

Description

Cross-references to related applications

[0001] This application claims priority to European patent application 24167310.2, filed on 28 March 2024, which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention relates to charged particle optical modules, multiple charged particle optical devices, charged particle optical apparatuses, evaluation devices, and methods for manufacturing charged particle optical modules. Background Technology

[0003] For example, during the manufacturing process of semiconductor integrated circuit (IC) chips or displays, unwanted defects may appear on the substrate (e.g., wafer) or mask. Such defects can reduce yield. Defects can arise from various processes required to produce integrated circuits or displays, such as photolithography, etching, deposition, or chemical mechanical polishing.

[0004] Defects can include patterning defects, where the created pattern exceeds the pattern tolerance of the process, and particles. Therefore, the extent to which defects are monitored during the manufacturing process is important. Such monitoring (or more generally, assessment) includes determining the presence of defects and classifying the types of defects found.

[0005] For sample evaluation, different types of inspection or metrology systems have been used, including charged particle systems (such as electron microscopes). Such evaluations for inspection can involve defects, such as their presence and classification. Electron microscopes typically generate a probe beam (also often called a primary beam), which can be scanned, for example, across a portion of the substrate (as in scanning electron microscopy (SEM)). By collecting the interaction products generated by the interaction of the primary beam with that portion of the substrate, the electron microscope is able to collect data representing the probed portion of the substrate.

[0006] This data can, for example, be processed / rendered by an electron microscope to generate an image representation of that portion of the substrate. The collected data (e.g., in the form of the generated image representation) allows for the measurement of structures on that portion of the substrate, or allows for the identification of defective structures by comparing the image representation with a reference image. Such measurements can be referred to as metrology; such defect inspections can be referred to as inspections. Interaction products can include charged particles, which can be referred to as signal particles (e.g., signal electrons), such as secondary electrons and backscattered electrons, and can include other interaction products, such as X-ray radiation.

[0007] The primary beam can originate from a source beam emitted from a free source. Multiple sources can be provided. Aligning various components of the sources may be difficult. The goal is to reduce the time required to perform alignment. Summary of the Invention

[0008] According to one aspect of the invention, a charged particle optical module for a plurality of charged particle optical devices is provided, the charged particle optical devices being configured to guide a charged particle beam toward a sample location along a respective beam path, the charged particle optical module comprising: at least one emitter disposed at an emitter surface of an emitter layer, each emitter being configured to emit charged particles for a source beam; at least one extractor electrode for the at least one emitter, wherein the at least one extractor electrode is planar and defines a beam aperture for the charged particles emitted by the respective emitter in each extractor electrode; and a spacer configured to space each extractor electrode from the emitter surface, wherein the spacer is an electrical insulator and includes an insulating surface located between the extractor electrode and the emitter surface, wherein at least a portion of the insulating surface is angled relative to a direction perpendicular to the emitter surface.

[0009] According to another aspect of the invention, a method for manufacturing a charged particle optical module is provided, the charged particle optical device being configured to guide a charged particle beam toward a sample location along a beam path, the method comprising: arranging at least one emitter at an emitter surface of an emitter layer, each emitter being configured to emit charged particles for a source beam; defining a beam aperture for charged particles emitted by the respective emitter in each of at least one extractor electrode for the at least one emitter, wherein the at least one extractor electrode is planar; and spacing each extractor electrode from the emitter surface with a spacer, wherein the spacer is an electrical insulator and includes an insulating surface located between the extractor electrode and the emitter surface, wherein at least a portion of the insulating surface is angled relative to a direction perpendicular to the emitter surface. Attached Figure Description

[0010] Now, we will only use examples, referring to the attached document. Schematic diagram The embodiments of the present invention are described in the accompanying drawings:

[0011] Figure 1 This is a schematic diagram of an exemplary evaluation device;

[0012] Figure 2 Schematic depiction of, for example Figure 1 The evaluation device is a multi-beam charged particle optical instrument;

[0013] Figure 3 An array of charged particle optical devices is schematically depicted;

[0014] Figure 4 The source of the charged particle optical module is schematically depicted;

[0015] Figure 5 Schematic depiction including Figure 4 The image shows a charged particle optical module with multiple sources.

[0016] Figure 6 yes Figure 5 A plan view of the charged particle optical module shown;

[0017] Figure 7 yes Figure 5 A plan view showing an alternative arrangement of the charged particle optical module; and

[0018] Figure 8 Multiple sources for multi-beam charged particle optics are schematically depicted.

[0019] The accompanying drawings are schematic. In the following description of the drawings, the same or similar reference numerals refer to the same or similar parts or entities, and only differences with respect to the various embodiments are described. Although the description and drawings are directed to electro-optical devices, it should be understood that these embodiments are not intended to limit this disclosure to specific charged particles. Therefore, throughout this document, references to electrons and articles referred to by electrons can be more generally understood to refer to charged particles and articles referred to by charged particles, wherein charged particles are not necessarily electrons. For example, references to electro-optical devices can be more generally understood to refer to charged particle optical devices. Detailed Implementation

[0020] There is a trend in the semiconductor industry (often referred to as "Moore's Law") that aims to reduce the physical size of structures representing circuit components on a substrate and / or increase the packaging density of such structures in order to reduce the physical size of electronic devices and / or enhance their computing power. The physical size of such structures can be reduced and / or the packaging density can be increased by improving lithographic resolution. The manufacturing process of a semiconductor IC chip can have hundreds of individual steps. Errors in any step of the manufacturing process can adversely affect the functionality of the electronic device. Improving the overall yield of the manufacturing process is desirable. For example, for a 50-step manufacturing process (where steps can indicate the number of layers formed on the substrate), to achieve a 75% yield, each individual step must have a yield greater than 99.4%. If individual steps have a 95% yield, the overall yield of the manufacturing process will be as low as 7-8%. Rapid defect identification is desired to maintain high substrate throughput, defined as the number of substrates processed per hour.

[0021] Figure 1This is a schematic diagram illustrating an exemplary evaluation apparatus 100, such as a metrology or inspection apparatus. The evaluation apparatus 100 can be configured to scan a sample with one or more electron beams. For example, the sample can be a semiconductor substrate, a substrate made of other materials, or a mask. Electrons interact with the sample and generate interaction products. These interaction products include signal electrons, such as secondary electrons and / or backscattered electrons, and may include X-ray radiation. The evaluation apparatus 100 can be configured to detect the interaction products from the sample so that a dataset can be generated, which can be processed into an image of the scanned area of ​​the sample or any other data representation. For clarity, the following description focuses on embodiments where the detected interaction products are signal electrons. For example, during operation, the evaluation apparatus 100 can include a single beam or multiple beams, i.e., multiple beams. The component beams of the multiple beams can be referred to as sub-beams or beam waves. Multiple beams can be used to scan different portions of the sample simultaneously. When the evaluation apparatus 100 uses multiple beams, the evaluation apparatus 100 can evaluate the sample more quickly than when the evaluation apparatus 100 uses a single beam. For example, using a multi-beam evaluation apparatus can achieve a higher throughput of sample evaluation than a single-beam apparatus.

[0022] Figure 1 Evaluation apparatus 100 includes a vacuum chamber 110, a loading and locking chamber 120, an electron optics unit 140, an equipment front-end module (EFEM) 130, and a controller 150. The electron optics unit 140 (also referred to as an electron beam device or electron device) may be located within the vacuum chamber 110. The electron optics unit 140 may include electron optical equipment (described in more detail below) and an actuable stage. It should be understood that references to electron optical elements of the electron optics unit 140 in this specification may be considered references to the electron optical equipment itself.

[0023] EFEM 130 includes a first loading port 130a and a second loading port 130b. EFEM 130 may include additional loading ports(s). For example, the first loading port 130a and the second loading port 130b may receive a substrate front-opening transfer box containing a sample. One or more robotic arms (not shown) in EFEM 130 transport the sample to the loading locking chamber 120.

[0024] Loading-lock chamber 120 is used to remove gas surrounding the sample. Loading-lock chamber 120 can be connected to a loading-lock vacuum pump system (not shown), which removes gas particles within loading-lock chamber 120. Operation of the loading-lock vacuum pump system enables the loading-lock chamber to reach a first pressure below atmospheric pressure. Vacuum chamber 110, which can be the main chamber of evaluation device 100, is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas molecules from vacuum chamber 110 so that the pressure around the sample reaches a second pressure equal to or below the first pressure. Different sections of electron optics device 140 can have different pressure levels below atmospheric pressure. After the desired pressure is reached, the sample leaves loading-lock chamber 120 and is transported to electron optics device 140 for evaluation. Electron optics device 140 can use a single beam or multiple beams for evaluation. Alternatively, an array of electron optics devices, also known as a multi-column electron array, can be used, where each electron optics device (or each column in the multi-column array) includes, for example, a single beam or multiple beams during operation.

[0025] Controller 150 is electrically connected to electro-optical device 140. Controller 150 may be a processor (such as a computer) configured to control evaluation device 100. Controller 150 may also include a processing circuitry system configured to perform data, signal, and image processing functions, such as performing data processing functions on the dataset (e.g., embodied as a signal, such as a detection signal). Therefore, controller 150 may include a processing circuitry system configured to perform processing functions on signals, images, and other data generated in evaluation device 100. Although controller 150 is... Figure 1 The controller 150 is shown outside the structure including the vacuum chamber 110, the loading and locking chamber 120, and the EFEM 130; however, it should be understood that the controller 150 may be part of the structure. The controller 150 may be located in one of the components of the evaluation device 100, or may be distributed on at least two of the components.

[0026] Figure 2 This is a schematic diagram illustrating an exemplary electro-optical device 140. The electro-optical device 140 can serve as... Figure 1 A portion of the evaluation apparatus 100 is provided. Electro-optical apparatus 140 includes a source 201 and an electron-optical device 230 (also referred to as an electron-optical array). Source 201 may include an emitter (not shown), which may be a cathode and an extractor and / or an anode (not shown). During operation, source 201 is configured to emit electrons from the emitter. The electrons may be extracted or accelerated by the extractor and / or the anode to form a source beam 202.

[0027] Electron optics device 230 can be configured to convert source beam 202 into multiple primary beams 211, 212, 213 (which may be referred to as sub-beams or beam waves). Electron optics device 230 can be configured to guide the primary beams 211, 212, 213 toward a sample location on sample 208 along corresponding beam paths. Although three beams are shown, the number of beams can be on the order of hundreds or thousands, for example, up to 20,000 per electron optics device 140. Multiple beams can be collectively referred to as multiple beams or beam grids. Different beams can be arranged opposite each other in a pattern on the beam grid. The pattern of the beam grid can be referred to as an array. Electron optics device 230 has a field of view, which can define an area of ​​the surface of sample 208 in which the primary beams 211, 212, 213 can be scanned while the aberrations of electron optics device 230 remain within defined values. Alternatively, the field of view can be defined by the maximum scanning range of electron optics device 230. The field of view can be on the order of millimeters, for example, up to 20 mm at sample 208.

[0028] Electro-optical device 230 includes a plurality of electro-optical elements positioned along a beam path. These electro-optical elements are configured to manipulate the beams. For example, the electro-optical elements may be configured to lens, focus, deflect, or correct the beams. The electro-optical elements may be arranged in at least one electro-optical element stack. Such electro-optical elements may be positioned upstream or downstream relative to another electro-optical element. The terms upstream and downstream refer to the direction of the beam from source 201 to sample 208 during use of electro-optical device 230, which may be expressed as a direction along one or more beam paths. In embodiments, some different electro-optical elements may take the form of planar elements, such as plates 261. An electric field for manipulating the beam may be generated between two plates 261, for example by applying different potentials to adjacent / adjacent plates 261 during use, such as along the beam path. The electric field for manipulating the beam may be generated between the surfaces of plates 261 across the beam path, for example between adjacent plates 261. One or more beam apertures 266 may be defined in plates 261 for the passage of one or more beams. The beam aperture 266 can be arranged in a pattern, such as a regular grid, like hexagons or squares. This pattern of the beam aperture 266 can be referred to as an aperture array (i.e., a two-dimensional array on the plate surface). The pattern of the beam aperture 266 can correspond to a beam pattern within a beam grid. Beam apertures 266 located on different plates and operating on the same(multiple) beams(s) are typically aligned.

[0029] Electro-optical elements may include one or more corrector arrays. For example, a corrector array may be integrated into the shape, location, and / or size of the beam aperture 266 of plate 261. The disclosure of such a corrector array described in WO 2022101072A1 is hereby incorporated by reference. One or more corrector arrays may include multipole deflectors having a specific potential superposition applied to individual controllable electrodes. The multipole deflector array disclosed in WO 2012165955 is hereby incorporated by reference.

[0030] One or more electro-optical elements may include apertures for paths of multiple beams. For example, the aperture may be a macroaperture for all beams. The disclosures of slit apertures including strip electrodes for collimators or correctors, as disclosed in WO 2021156121A1 and WO 2021204734A1, are incorporated herein by reference. One or more electro-optical elements may include one or more plate electrodes with paths bent across a beam grid for use as lens arrays, corrector arrays, and / or collimator arrays, such as those disclosed in European Patent Application 23211553.5, filed November 22, 2023, which is incorporated herein by reference, at least with respect to the use and application of bent plate electrodes.

[0031] In the current embodiment, the electron optics device 230 can form three probe spots 281, 282, and 283 on the surface of the sample 208. The electron optics device 230 can be configured to deflect primary beams 211, 212, and 213 so that probe spots 281, 282, and 283 scan across individual scanning areas of the sample 208. In response to the incident primary beams 211, 212, and 213 on the sample 208, signal electrons are generated from the sample 208, which may include secondary electrons and backscattered electrons. Secondary electrons typically have an electron energy of up to 50 eV. Backscattered electrons typically have an electron energy greater than 50 eV and less than the landing energy of the primary beams 211, 212, and 213.

[0032] Electron-optical device 140 includes a sample holder 207 supporting a sample 208. The sample holder 207 supports the sample 208 used for evaluation. The sample holder 207 is supported by an actuable stage 209. Electron-optical device 140 also includes a detector array 240. The detector array 240 may be part of electron-optical device 230. The detector array 240 detects, for example, signal electrons from the sample 208. The detector array 240 generates a detection signal based on the detection of the signal electrons.

[0033] In an embodiment, detector array 240 may define the surface of electro-optical device 140 facing sample 208, such as the bottom surface of electro-optical device 230. More than one detector array may be present at different locations along the path of primary beams 211, 212, 213.

[0034] Detector array 240 may include multiple detector elements, with at least one detector element per beam. Detector elements may be, for example, charge-trapping electrodes, such as metal plates, configured to detect at least some of the signal electrons. Alternatively or additionally, detector elements may include detection diodes configured to detect at least some of the signal electrons. Alternatively or additionally, detector elements may include scintillator material (such as YAG) configured to convert signal electrons into photons that can subsequently be detected. Detector elements may be arranged around beam aperture 266 in the bottom surface of electron optics device 230 to allow primary beams 211, 212, 213 to pass toward sample 208. Each detector element may include multiple detection segments, or may constitute a single sensitive surface for each beam. Detection signals generated by the detector elements may be transmitted to a processor for image generation. For example, the detection signals may represent grayscale or intensity values ​​of pixels in the image.

[0035] Detector array 240 can transmit detection signals (e.g., as image signals or detection signals) to controller 150 or a signal processing system (not shown), which may be part of controller 150. Controller 150 or the signal processing system can be configured to generate an image of a corresponding scanned area of ​​sample 208. Detector array 240 may be at least partially incorporated into electro-optical device 230. Alternatively, detector array 240 may be separate from electro-optical device 230. For example, electro-optical device 140 may include a secondary electro-optical device configured to direct secondary electrons to detector array 240. In such an embodiment, the secondary electro-optical device includes a beam splitter (such as a Wien filter, not shown). The beam splitter can separate the path of primary electrons toward sample 208 from the path of signal electrons leaving sample 208. Note that in different embodiments, such a beam splitter may be present within electro-optical device 230, which has a detector array for directing primary electrons toward the sample and directing signal particles toward detector elements of the detector array.

[0036] Controller 150 (e.g., a control system including a distributed controller) can be connected to Figure 2The various parts (e.g., components) of the electro-optical device 140 include the source 201, detector array 240, electro-optical device 230, and actuable stage 209. The controller 150 can perform various image processing and signal processing functions. The controller 150 can also generate various control signals to manage the operation of the evaluation device 100.

[0037] Figure 3 An array of electro-optical devices 299 is schematically depicted. In an embodiment, Figure 1 The evaluation apparatus 100 includes an electro-optical device array 299 instead of an electro-optical device 140. Such an electro-optical device array 299 is also referred to as a multi-column array. Different columns (or electro-optical devices 230) may include multiple beams, such as beam grids, in use. In this embodiment, the electro-optical device array 299 includes multiple... Figure 2 Electro-optical device 230 of the type shown.

[0038] In one embodiment, one or more electro-optical elements may be shared among more than one electro-optical device 230 of the electro-optical device array 299. An electro-optical element may include one or more plates 261, wherein a plurality of beam apertures 266 are defined for a corresponding beam path. In another embodiment, one or more sources 201 may be shared among more than one electro-optical device 230 of the electro-optical device array 299. Sources may be included in a source array having different sources that generate source beams for different corresponding electro-optical devices 230.

[0039] Electro-optical devices 230 can simultaneously focus multiple beams onto different regions of the same sample 208. In different embodiments, the electro-optical devices 230 of the electro-optical device array 299 can project a single beam toward the sample 208.

[0040] Each electro-optical device 230 of the electro-optical device array 299 may be configured in any manner as described herein. The disclosure in WO 2022008286 A1 regarding how objectives are incorporated and suitable for use in a multi-device arrangement is incorporated herein by reference. The disclosure in WO 2021165135 A1 regarding a multi-device arrangement of a multi-beam device, including a collimator located at or near the intermediate focal point, is incorporated herein by reference.

[0041] In embodiments, any electro-optical element or group of electro-optical elements may be replaceable within the electro-optical device 140 or field-replaceable. Field-replaceable means that the electro-optical element or group of electro-optical elements can be replaced without extensive disassembly of the electro-optical device 140. In embodiments, the electro-optical device 140 includes at least one module. Each module includes a set of adjacent electro-optical elements. The electro-optical elements of a module may be fixed to each other, for example, as a stack.

[0042] Features in the electro-optical plate can be fabricated using techniques from microelectromechanical systems (MEMS), i.e., MEMS fabrication techniques. MEMS are miniaturized mechanical and electromechanical components fabricated using microfabrication techniques. As just one example, collimator arrays can be formed using MEMS fabrication techniques to achieve a compact spatial arrangement. As another example, scan deflector arrays can be formed using MEMS fabrication techniques.

[0043] A power source can be provided to power the evaluation device 100 and / or the electro-optical device 140. For example, such a power source can apply a corresponding potential to the electrodes of the lens of the electro-optical device 230.

[0044] In one embodiment, controller 150 is configured to control electro-optical device 230. The controller 150 may be configured to control the potential applied to the electrodes of the lens of the electro-optical device 230.

[0045] In an embodiment, controller 150 is configured to control actuable stage 209 to move the sample 208 during examination. Controller 150 can enable actuable stage 209 to move the sample 208 in one direction (e.g., continuously, such as at a constant speed), at least during sample examination, which can be referred to as a type of scan. The speed of actuable stage 209 can be referred to as the rate of movement. Controller 150 can control the movement of actuable stage 209 to vary the speed of movement of the sample 208 relative to the beam path according to one or more parameters. Controller 150 can control the deflection of the scan deflector, thereby moving the beam path relative to the actuable stage 209 and thus scanning the surface of the sample 208. Controller 150 can vary the beam deflection of the scan deflector according to one or more parameters, and thus vary the scanning of the primary beams 211, 212, 213 on the sample 208. For example, controller 150 can control the speed of the scan deflector and / or the direction of movement of the actuated stage 209 based on the characteristics of the evaluation process. The disclosure of the stepping and scanning combination strategy for the stage and scan deflector in EP4086933 A1 is incorporated herein by reference. The movement rate may include the stepping frequency and / or the stage scan rate at different times.

[0046] like Figure 2 As shown, in this embodiment, the electro-optical device 140 includes an electro-optical module 200. The electro-optical module 200 may include a source 201.

[0047] like Figure 3 As shown, in this embodiment, the electro-optical device array 299 includes an electro-optical module 200. The electro-optical module 200 may include a plurality of sources 201. For example, the electro-optical module 200 may include a plurality of sources 201 for respective plurality of electro-optical devices 230.

[0048] Figure 4 The source 201 of the electro-optics module 200 is schematically depicted. The electro-optics module 200 may include multiple sources 201. The electro-optics module 200 may have the features described above with reference to other figures, except for the differences described below.

[0049] For ease of explanation, Figure 4 Only one source, 201, is shown. Figure 5 schematically depicted Figure 4 The electro-optical module 200 includes multiple sources 201. The sources 201 can be included in an array. Each source 201 corresponds to a transmitter 21.

[0050] In an embodiment, source 201 includes an avalanche diode structure. The avalanche diode structure includes a stack of doped semiconductor junctions and is biased from two connections. For example, the avalanche diode structure may include a PN junction or a PIN junction. The avalanche diode structure may include a homojunction or heterojunction of semiconductor stacks with different band gaps. In an embodiment, the avalanche diode structure includes a heterojunction of a silicon carbide P-type substrate with a gallium nitride N++ layer on top of the silicon carbide P-type substrate. Gallium nitride has a lower work function (approximately 1 eV lower), thus allowing more electrons to escape. Meanwhile, silicon carbide has high thermal conductivity and the ability to be P-type. The band gap structure affects the electron energy distribution in the avalanche region of the avalanche diode structure. Source 201 may be based on an avalanche electron emission diode (AEED) as the emitter technology. AEED emitters are semiconductor-based emitters. AEEDs may alternatively be referred to as avalanche cold cathodes or semiconductor junction cold cathodes. In an embodiment, source 201 is junction-based. For example, emitter 21 may include a diode junction, such as a PN junction. In an embodiment, source 201 includes multiple junctions. Each junction can be an interface between two layers or regions that are semiconductor-like or non-semiconductor-like. In an embodiment, a junction is an interface between doped materials. A junction can be a junction between two or more materials. Such a junction can be a diode. In an embodiment, source 201 is configured such that an avalanche current is generated within the diode of emitter 201, perpendicular to the surface facing sample 208. Some electrons are sufficiently excited in the avalanche region to overcome the work function of the surface and are emitted into the vacuum.

[0051] like Figure 4 As shown, in this embodiment, each source 201 includes a transmitter 21. The transmitter 21 is configured to emit an electron beam along a source path. Figure 4 In the orientation shown, the source path extends vertically upwards from the transmitter 21. In such an orientation... Figure 5 In the orientation shown, the source path extends vertically downward from the transmitter 21.

[0052] like Figure 4 As shown, in this embodiment, the electro-optics module 200 includes a substrate element 84. The substrate element 84 may be planar. The substrate element 84 may be formed as a layer. For example, the electro-optics module 200 may include a base substrate 83. The base substrate 83 may include silicon. For example, the base substrate 83 may be a SiC substrate. In this embodiment, the substrate element 84 is formed on the base substrate 83 by epitaxy (e.g., molecular beam epitaxy).

[0053] like Figure 4As shown, in one embodiment, substrate element 84 includes a transmitter 21. In another embodiment, substrate element 84 also includes one or more electrical connectors. The electrical connectors can be used to transmit control signals and / or electrical power. The electrical connectors can be formed as traces within substrate element 84. In another embodiment, the electrical connectors include electrical conductors, such as metals, for example, copper.

[0054] In this embodiment, the emitter 21 is formed from a PN junction. The region of the emitter 21 may correspond to the highly p-doped region 87 of the PN junction. The highly p-doped region 87 is more heavily doped than the substrate element 84. In this embodiment, the substrate element 84 is a p-doped layer.

[0055] like Figure 4 As shown, in one embodiment, source 201 includes extractor electrode 27. Extractor electrode 27 may correspond to emitter 21. In one embodiment, electro-optics module 200 includes multiple extractors 27 for corresponding multiple emitters 21. Figure 4 As shown, in this embodiment, the extractor electrode 27 is spaced apart from the transmitter 21 along the source path.

[0056] like Figure 4 As shown, in one embodiment, source 201 includes an N-doped region 85. In one embodiment, the N-doped region 85 substantially surrounds a highly P-doped region 87 of emitter 21. In one embodiment, the N-doped region 85 is spaced from the highly P-doped region 87. For example, as... Figure 4 As shown, the volume of the substrate element 84 can exist between the N-doped region 85 and the highly P-doped region 87.

[0057] like Figure 4 As shown, in this embodiment, source 201 includes a highly N-doped layer 86. Compared to N-doped layer 85, the highly N-doped layer 86 can be even more N-doped. Figure 4 As shown, in this embodiment, a highly N-doped layer is located between the highly P-doped layer 87 and the extractor electrode 27. The highly N-doped layer 86 may be located on the surface of the substrate element 84. In this embodiment, the highly N-doped layer 86 is configured to radially draw electrons away from the highly P-doped layer 87.

[0058] like Figure 4 As shown, the transmitter 21 can be located at the transmitting surface 80 of the electro-optical module 200.

[0059] like Figure 4As shown, in one embodiment, the electro-optics module 200 includes a spacer 88. The spacer 88 is configured to space each extractor electrode 27 from the emitting surface 80. An emitter 21 is disposed at the emitting surface 80 of the emitter layer. The emitter layer includes the emitter 21. In one embodiment, the spacer 88 is configured to electrically insulate the extractor electrode 27 from the emitting surface 80. The spacer 88 may be an electrical insulator. During use of the electro-optics module 200, the extractor electrode 27 and the emitting surface 80 may have different potentials. A potential difference may exist between the extractor electrode 27 and the emitting surface 80. The spacer 88 is configured to help maintain this potential difference.

[0060] like Figure 4 As shown, in this embodiment, the spacer 88 includes an insulating surface 94. The insulating surface 94 is located between the extractor electrode 27 and the emitting surface 80. Figure 4 As shown, in this embodiment, at least a portion of the insulator surface 94 is angled relative to a direction perpendicular to the emitting surface 80. For example, in Figure 4 In the illustrated arrangement, the insulator surface 94 may include a first vertical portion, a horizontal portion, and a second vertical portion. The horizontal portion is angled (e.g., perpendicular) to a direction perpendicular to the emitting surface 80. The vertical portions of the insulator surface 94 may be parallel to a direction perpendicular to the emitting surface 80. In embodiments, the angled portions of the insulator surface 94 may be referred to as angled surfaces. The two vertical portions may form the inner surfaces of layers 89, 90 of the spacer 88. Figure 4 In the example shown, the horizontal angled surface can be part of the downstream surface of the first layer 89 of the spacer 88.

[0061] Figure 4 The illustrated electro-optics module 200 includes a plurality of spacers 88. The spacers 88 are configured to space the substrate element 84, including the emitter 21, from the extractor 27. Figure 4 As shown, in this embodiment, the spacer 88 substantially surrounds the source path in a plan view. The spacer 88 may have an edge profile to increase the path length along the insulating surface 94 of the spacer 88 between the emitter 21 and the extractor electrode 27. For example, the insulating surface 94 may be stepped.

[0062] like Figure 4 As shown, in this embodiment, the spacer 88 includes multiple layers 89, 90. The layers 89, 90 may have different dimensions in the direction across the source path. For example, the first layer 89, closer to the transmitter 21, may have a larger dimension in the direction across the source path. The second layer 90 on the extractor side may have a smaller dimension in the direction across the source path. The spacer 88 is arranged to reduce the possibility of electrical breakdown between the transmitter 21 and the extractor electrode 27.

[0063] In embodiments, the first layer 89 and the second layer 90 of the spacer 88 are formed of different materials. The first layer 89 and the second layer 90 may be referred to as spacer layers 89 and 90. For example, in embodiments, at least one of the spacer layers 89 and 90 comprises silicon dioxide. In embodiments, at least one of the spacer layers 89 and 90 comprises hafnium oxide. According to an embodiment of a method of manufacturing an electro-optical module 200, the method includes etching a plurality of spacer layers 89 and 90 of the spacer 88. For example, in embodiments, the etching is wet etching. In embodiments, the spacer layers 89 and 90 are formed of different materials that have different etching rates to the etchant used for wet etching.

[0064] like Figure 5 As shown, in this embodiment, the spacer 88 surrounds each beam path from each emitter 21. In the electro-optical plate element, the extractor electrodes 27 can be electrically decoupled from each other. For example, as... Figure 6 or Figure 7 As shown, electron optical plate elements can be deposited and then etched to create ring islands.

[0065] In this embodiment, spacer 88 is fabricated by growing a dielectric layer. By etching holes in the dielectric layer, spacer 88 is a layer having holes for beam paths from each source 201.

[0066] Embodiments of the present invention including spacer 88 are intended to reduce the electric field at the triple junction involving spacer 88. This triple junction is the point where spacer 88 contacts the atmosphere and an electrical conductor (e.g., extractor electrode 27). Embodiments of the present invention are intended to reduce the likelihood of undesirable electrical breakdown.

[0067] In one embodiment, the extractor electrode 27 comprises a non-magnetic material. In another embodiment, the extractor electrode 27 comprises a material that is not easily oxidized. For example, the extractor electrode 27 may comprise a material other than aluminum. The extractor electrode 27 comprises a conductive material. In one embodiment, the extractor electrode 27 comprises tungsten.

[0068] Figure 4 The circuitry for applying potentials to the transmitter 27 and the extractor electrode 27 is schematically depicted. For example... Figure 4As shown, different potentials are applied to each of the extractor electrode 27, the N-doped region 85, and the highly P-doped region 87. In an embodiment, one or more of the highly P-doped region 87, the N-doped region 85, and the extractor electrode 27 are connected to one or more power sources via electrical connections of the substrate element 84. In an embodiment, power source 91 applies a potential difference between the highly P-doped region 87 and the N-doped region 85. A second power source 92 may apply a potential difference between the N-doped region 85 and the extractor electrode 27. In an embodiment, the N-doped region 85 serves as the anode. In an embodiment, a common potential is applied to multiple N-doped regions 85. Different potentials may be applied to the extractors 27 corresponding to different emitters 21.

[0069] Extractor 27 can be included in the extractor arrangement as an electro-optical plate element. In embodiments, electro-optical module 200 includes one or more other electro-optical plate elements. For example, although in Figure 5 Not shown, but in embodiments, the electro-optics module 200 includes a beam-limiting aperture array and / or a single-beam corrector array. In embodiments, the beam-limiting aperture array and / or single-beam corrector array may be shared by multiple (optionally all) transmitters 21.

[0070] Figure 6 schematically depicted Figure 5 The diagram shows the layout of the electron optics module 200. Figure 6 As shown, in this embodiment, the extractors 27 are physically separated from each other. When viewed in a plan view, each extractor electrode 27 substantially surrounds the emitter 21. Spacers 88 may be exposed between the extractors 27.

[0071] like Figure 6 As shown, in this embodiment, the extractor 27 has a substantially circular outer perimeter. However, a circular outer perimeter for the extractor electrode 27 is not mandatory. In alternative embodiments, the outer perimeter is elliptical or polygonal, such as triangular or square (e.g., ...). Figure 7 (As shown), pentagonal or hexagonal. For example... Figure 6 As shown, in one embodiment, the extractor electrode 27 has a substantially circular inner perimeter. However, a circular inner perimeter is not mandatory. In alternative embodiments, the inner perimeter of the extractor electrode 27 is elliptical or polygonal, such as a triangle, square, pentagon, or hexagon.

[0072] like Figure 6 As shown, in this embodiment, the extractors 27 are arranged in an array. In this embodiment, the array forms a grid. Figure 6 As shown, in this embodiment, the grid can be a hexagonal grid. Alternatively, the grid can be a square or rectangular grid.

[0073] Figure 7 An alternative arrangement of extractor 27 is shown. Figure 7 In the embodiment shown, the extractor 27 has a substantially rectangular outer perimeter.

[0074] Figure 8 Multiple sources 201 for the multi-beam electro-optical device 230 are schematically depicted. Figure 8 The vacuum chamber 60 of the electron optics module is schematically depicted. Figure 8 In the arrangement shown, source 201 may include an avalanche diode structure, such as that described above.

[0075] like Figure 8 As shown, in this embodiment, a vacuum device 61 is provided for the vacuum chamber 60. In use, the vacuum device 61 is configured to maintain a source undervoltage within the vacuum chamber 60. For example, the vacuum device 61 may include one or more pumps. In this embodiment, the vacuum device 61 includes one or more getter devices.

[0076] like Figure 8 As shown, in this embodiment, source 201 is located between vacuum device 61 and beam path. Vacuum device 61 is located upstream of source 201.

[0077] like Figure 8 As shown, in this embodiment, the electro-optical module includes a plurality of sources 201. Each source 201 may include a corresponding emitter 21. The emitters 21 may be arranged in an array.

[0078] like Figure 8 As shown, in one embodiment, the electro-optics module includes an anode element 81. The anode element 81 can be configured to serve as the anode of the source 201. In one embodiment, the anode element 81 also includes a single-beam corrector for correcting a single-source beam emitted by the transmitter 21 of the source 201. In one embodiment, the anode element 81 is a planar element, such as a plate.

[0079] like Figure 8 As shown, in one embodiment, the electro-optics module includes a beam-limiting aperture array 82. The beam-limiting aperture array 82 may define a plurality of beam-limiting apertures therein. The beam-limiting apertures may be configured to limit the source beam emitted by source 201. The beam-limiting aperture array 82 may be configured to block one portion of the electronic current and transmit another portion of the electronic current. In one embodiment, the beam-limiting aperture array 82 is substantially planar, such as a plate.

[0080] In an embodiment, the anode element 81 is configured to guide the source beam through the limiting aperture of the beam limiting aperture array 82.

[0081] like Figure 3As shown, in this embodiment, the plurality of electro-optical devices 23 may include an electro-optical module 200. The electro-optical module may be configured to generate a source beam for the electro-optical devices 230.

[0082] In an embodiment, each electro-optical device 230 includes an electro-optical element downstream of the electro-optical module 230. The electro-optical element of the electro-optical device 230 can be configured to operate on a source beam. The electro-optical element can be configured to operate on a primary beam sourced from the source beam generated by the electro-optical module 200.

[0083] In one embodiment, the electro-optical elements of the electro-optical device 230 are configured to operate on a corresponding source beam or a primary beam derived from a corresponding source beam. Alternatively, the electro-optical elements may be configured to operate on multiple source beams or primary beams derived from multiple source beams. Each electro-optical device 230 may have a source 201. Alternatively, each electro-optical device 230 may have multiple sources 201. Alternatively, the primary beams of multiple electro-optical devices 230 may originate from a source beam of a single source 201. The source 201 may be included in the same electro-optical module 200.

[0084] In an embodiment, the evaluation apparatus 100 includes an electro-optical device 140. The electro-optical device 140 may include a plurality of electro-optical devices 230. Each electro-optical device 230 may include at least one detector 240. The detector 240 may be configured to detect signal particles from the sample 208 when the sample is supported at the sample location. In an embodiment, at least one detector 240 includes one or more electro-optical plate elements. The detector interacts with electrons and therefore can be considered an electro-optical element.

[0085] Another embodiment of the invention is described in the following numbered clauses: 1. A charged particle optical module for use with a plurality of charged particle optical devices configured to guide a charged particle beam toward a sample location along a corresponding beam path, the charged particle optical module comprising: At least one emitter is arranged at the emission surface of the emitter layer, and each emitter is configured to emit charged particles for the source beam; At least one extractor electrode for the at least one emitter, wherein the at least one extractor electrode is planar and defines a beam aperture for charged particles emitted by the respective emitter in each extractor; and A spacer is configured to space each extractor electrode from the emitting surface, wherein the spacer is an electrical insulator and includes an insulating surface located between the extractor electrode and the emitting surface, wherein at least a portion of the insulating surface is angled relative to a direction perpendicular to the emitting surface. 2. The charged particle optical module according to Clause 1, wherein the insulator surface is stepped. 3. The charged particle optical module according to Clause 1 or 2, wherein the at least one extractor electrode is aligned relative to the at least one emitter. 4. The charged particle optical module according to any of the foregoing clauses, comprising a plurality of emitters. 5. The charged particle optical module according to Clause 4, comprising a plurality of extractor electrodes for the plurality of emitters. 6. The charged particle optical module according to Clause 4 or 5, comprising a plurality of spacers for the plurality of emitters. 7. The charged particle optical module according to any of the preceding clauses, wherein the spacer comprises a plurality of spacer layers formed of different materials. 8. The charged particle optical module according to Clause 7, wherein at least one of the spacer layers comprises silicon dioxide. 9. The charged particle optical module according to Clause 7 or 8, wherein at least one of the spacer layers comprises hafnium oxide. 10. The charged particle optical module according to any of the foregoing clauses, wherein the at least one extractor electrode is nonmagnetic. 11. The charged particle optical module according to any one of the preceding clauses, comprising: Planar charged particle optical elements are configured to operate individually on the one or more source beams. 12. The charged particle optical module according to any one of the foregoing clauses, comprising: A planar charged particle optical element is configured to shape the at least one source beam. 13. The charged particle optical module according to any of the preceding clauses, wherein the distance between the insulator surface at the emitting surface end of the insulator surface and the axis of the beam path of the charged particles emitted by the emitter is greater than the distance between the insulator surface and the axis at the extractor electrode end of the insulator surface. 14. The charged particle optical module according to any of the preceding clauses, wherein the spacer is planar. 15. The charged particle optical module according to any of the preceding clauses, wherein the at least one emitter comprises an avalanche diode structure. 16. A plurality of charged particle optical devices configured to guide a charged particle beam toward a sample location along a respective beam path, said plurality of charged particle optical devices comprising the charged particle optical module described in any of the preceding clauses. 17. The plurality of charged particle optical devices according to Clause 16, wherein each charged particle optical device includes a charged particle optical plate element located downstream of the charged particle optical module, the charged particle optical plate element being configured to operate on the source beam or on a primary beam derived from the source beam. 18. The plurality of charged particle optical devices according to Clause 17, wherein the charged particle optical plate element is configured to operate on a respective source beam or a primary beam derived from the respective source beam, or to operate on a plurality of the source beams or primary beams derived from the plurality of the source beams. 19. A charged particle optical device, comprising: Multiple charged particle optical devices as described in any one of Clauses 16-18; and An actuable stage is configured to support the sample at the sample location. 20. The charged particle optical device according to Clause 19, further comprising: It includes the plurality of charged particle optical devices and the vacuum chamber of the actuable stage. 21. An evaluation apparatus for evaluating a sample, comprising the charged particle optical apparatus of claim 19 or 20, wherein the plurality of charged particle optical apparatuses includes at least one detector configured to detect signal particles from the sample when the sample is supported at the sample location. 22. The evaluation apparatus according to Clause 21, wherein the at least one detector comprises at least one of the charged particle optical plate elements. 23. A method for manufacturing a charged particle optical module for a charged particle optical device, the charged particle optical device being configured to guide a charged particle beam toward a sample location along a beam path, the method comprising: At least one emitter is arranged at the emission surface of the emitter layer, and each emitter is configured to emit charged particles for the source beam. A beam aperture for charged particles emitted by the respective emitter is defined in each of at least one extractor electrode used for the at least one emitter, wherein the at least one extractor electrode is planar; and Each extractor electrode is spaced apart from the emitting surface by a spacer, wherein the spacer is an electrical insulator and includes an insulating surface located between the extractor electrode and the emitting surface, wherein at least a portion of the insulating surface is angled relative to a direction perpendicular to the emitting surface. 24. The method described under Clause 23 includes: Align the at least one extractor electrode and the spacer relative to the transmitter. 25. The method described under Clause 24, comprising: After aligning the at least one extractor electrode and the spacer relative to the emitter, the charged particle optical module is incorporated into the charged particle optical device. 26. The method according to any one of clauses 23-25, wherein the spacing comprises: Etch multiple spacer layers of the spacer. 27. The method according to Clause 26, wherein the etching is a wet etching. 28. The method according to Clause 27, wherein the spacer layer is formed of different materials, the different materials having different etching rates to the etchant used for the wet etching.

[0086] While specific reference may be made herein to embodiments of the invention in an electron microscope setting, these embodiments can be used in other types of apparatuses. These embodiments can form part of a mask inspection apparatus, a metrology apparatus, or any apparatus for measuring or processing objects such as wafers (or other substrates) or masks (or other patterning apparatuses).

[0087] Although specific embodiments of the invention have been described above, it should be understood that the invention can be practiced in ways other than those described. The above description is intended to illustrate and not limit. Therefore, it will be apparent to those skilled in the art that modifications can be made to the described invention without departing from the scope of the claims set forth below.

Claims

1. A charged particle optical module for use with a plurality of charged particle optical devices configured to guide a charged particle beam toward a sample location along a corresponding beam path, the charged particle optical module comprising: At least one emitter is arranged at the emission surface of the emitter layer, and each emitter is configured to emit charged particles for the source beam; At least one extractor electrode for the at least one emitter, wherein the at least one extractor electrode is planar and a beam aperture is defined in each extractor electrode for the charged particles emitted by the corresponding emitter; as well as A spacer is configured to space each extractor electrode from the emitting surface, wherein the spacer is an electrical insulator and includes an insulating surface located between the extractor electrode and the emitting surface, wherein at least a portion of the insulating surface is angled relative to a direction perpendicular to the emitting surface.

2. The charged particle optical module according to claim 1, wherein the insulator surface is stepped.

3. The charged particle optical module according to claim 1 or 2, wherein the at least one extractor electrode is aligned relative to the at least one emitter.

4. The charged particle optical module according to any one of the preceding claims, comprising a plurality of emitters.

5. The charged particle optical module according to claim 4, comprising a plurality of extractor electrodes for the plurality of emitters.

6. The charged particle optical module according to claim 4 or 5, comprising a plurality of spacers for the plurality of emitters.

7. The charged particle optical module according to any one of the preceding claims, wherein the spacer comprises a plurality of spacer layers formed of different materials.

8. The charged particle optical module of claim 7, wherein at least one of the spacer layers comprises silicon dioxide.

9. The charged particle optical module according to claim 7 or 8, wherein at least one of the spacer layers comprises hafnium oxide.

10. The charged particle optical module according to any one of the preceding claims, wherein the at least one extractor electrode is nonmagnetic.

11. The charged particle optical module according to any one of the preceding claims, comprising: Planar charged particle optical elements are configured to operate individually on one or more source beams.

12. The charged particle optical module according to any one of the preceding claims, comprising: A planar charged particle optical element is configured to shape at least one source beam.

13. The charged particle optical module according to any one of the preceding claims, wherein the distance between the insulator surface at the emitting surface end of the insulator surface and the axis of the beam path of the charged particles emitted by the emitter is greater than the distance between the insulator surface at the extractor electrode end of the insulator surface and the axis.

14. The charged particle optical module according to any one of the preceding claims, wherein the spacer is planar.

15. The charged particle optical module according to any one of the preceding claims, wherein the at least one emitter comprises an avalanche diode structure.

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