Charged-particle optical module

Abstract

A charged particle optical module (200) for a charged particle optical apparatus configured to direct a charged particle beam along a respective beam path towards a sample position, the charged particle optical module comprising: an emitter (21) configured to emit a source beam of charged particles; a plurality of charged particle optical plate elements (24-26) configured to operate on the source beam and to define a plurality of beam apertures (266) for the passage of the source beam; and a spacer (33) configured to space two of the charged particle optical plate elements apart from each other, wherein the spacer comprises at least one engagement surface engaging one of the charged particle optical plate elements, the engagement surface being planar.

Description

Cross-references to related applications

[0001] This application claims priority to European patent application 24167258.3, 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 operating charged particle optical modules. Background Technology

[0003] For example, during the manufacturing process of semiconductor integrated circuit (IC) chips or displays, undesirable 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. Defects can include patterning defects, where the created pattern exceeds the pattern tolerance of the process, as well as particles. Therefore, the extent to which defects are monitored during the manufacturing process is important. Such monitoring (or more generally, evaluation) includes determining the presence of defects and classifying the types of defects found.

[0004] For sample evaluation, different types of inspection or metrology systems have been used, including charged particle systems (such as electron microscopy). Such evaluations for inspection can involve defects, such as their presence and classification. Electron microscopy typically generates a probe beam (also often called a primary beam), which can, for example, be scanned across a portion of a substrate (such as in scanning electron microscopy (SEM)). By collecting the interaction products resulting from 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. This data can, for example, be processed / rendered by the 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 contain charged particles, which can be called signal particles (e.g., signal electrons), such as secondary electrons and backscattered electrons, and can contain other interaction products, such as X-ray radiation.

[0005] The primary beam can originate from a source beam emitted from a free source. The aim is to make the source more compact without unduly increasing the risk of electrical breakdown. Summary of the Invention

[0006] According to one aspect of the invention, a charged particle optical module for a charged particle optical device is provided, the charged particle optical device being configured to guide a charged particle beam toward a sample location along a respective beam path, the charged particle optical module comprising: a plurality of emitters configured to emit respective charged particle source beams; a plurality of charged particle optical plate elements configured to operate on the source beams and define a plurality of beam apertures for the source beams to pass through, wherein at least one of the charged particle optical plate elements is common to the plurality of emitters; and a spacer configured to space two of the charged particle optical plate elements apart from each other, wherein the spacer includes at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar.

[0007] According to another aspect of the invention, a charged particle optical module for a charged particle optical device is provided, the charged particle optical device being configured to guide a charged particle beam toward a sample location along a respective beam path, the charged particle optical module comprising: an emitter configured to emit a source beam of charged particles; a plurality of charged particle optical plate elements configured to operate on the source beam and define a plurality of beam apertures for the source beam to pass through; and a spacer configured to space two of the charged particle optical plate elements apart from each other, wherein the spacer includes at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar.

[0008] According to another aspect of the invention, a method is provided for operating a charged particle optical module for a charged particle optical device, configured to guide a charged particle beam toward a sample location along a respective beam path, the method comprising: emitting a source beam of charged particles from a respective emitter; and operating the source beam using a plurality of charged particle optical plate elements, the charged particle optical plate elements defining a plurality of beam apertures through which the source beam passes, wherein at least one of the charged particle optical plate elements is common to the plurality of emitters; wherein two of the charged particle optical plate elements are spaced apart from each other by spacers, wherein the spacers include at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar.

[0009] According to another aspect of the invention, a method is provided for operating a charged particle optical module for a charged particle optical device, configured to guide a charged particle beam toward a sample location along a respective beam path, the method comprising: emitting a source beam of charged particles from an emitter; and operating the source beam using a plurality of charged particle optical plate elements, the charged particle optical plate elements defining a plurality of beam apertures for the source beam to pass through; wherein two of the charged particle optical plate elements are spaced apart from each other by spacers, wherein the spacers include at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar. Attached Figure Description

[0010] Embodiments of the invention will now be described by way of example only, with reference to the accompanying schematic diagrams, in which:

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

[0012] Figure 2 A schematic depiction of a multi-beam charged particle optical device, such as... Figure 1 The equipment for the evaluation device;

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

[0014] Figure 4 A charged particle optical module comprising multiple sources is schematically depicted.

[0015] Figure 5 The spacer is schematically depicted, for example, as shown below. Figure 4 Spacers for charged particle optical modules;

[0016] Figure 6 schematically depicted Figure 4 A plan view of the stacked layers of the charged particle optical module shown;

[0017] Figure 7 schematically depicted Figure 6 The side view of the stack shown;

[0018] Figure 8 A schematic depiction of a charged particle optical module comprising a single source; and

[0019] Figure 9 A vacuum chamber is schematically depicted.

[0020] 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

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 in 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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 individually controllable electrodes. The multipole deflector array disclosed in WO 2012165955 is hereby incorporated by reference.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Detector array 240 can transmit detection signals, such 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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 and / or direction of movement of the scan deflector and / or the actuable 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.

[0047] 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.

[0048] 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.

[0049] Figure 4 An electro-optical module 200 according to an embodiment of the present invention is schematically depicted. The electro-optical module 200 may be referred to as a multi-source module. The electro-optical module 200 may include a plurality of emitters 21. Figure 3 As shown, in this embodiment, the electro-optics module 200 is used for a plurality of electro-optics devices 230. These electro-optics devices 230 can be configured to guide an electron beam along a corresponding beam path toward the sample location where the sample 208 is positioned.

[0050] like Figure 4 As shown, in this embodiment, the electro-optics module 200 includes a plurality of emitters 21. Each emitter 21 can be configured to emit a corresponding electron source beam 202. The source beam 202 can be emitted along a corresponding source path. The source path can be the path along which the electrons of the source beam 202 travel. Figure 4 Two transmitters 21 of the corresponding source 201 are schematically shown. The two transmitters 21 are shown to illustrate the features of the electro-optical module 200. The electro-optical module 200 may include at least 3, optionally at least 5, optionally at least 10, optionally at least 20, optionally at least 50, optionally at least 100, optionally at least 200, optionally at least 500, and optionally at least 1000 transmitters 21 of the corresponding source 201.

[0051] In an embodiment, each source 201 is configured to generate a source beam 202 for a corresponding electro-optical device 230. Each electro-optical device 230 may include one or more electro-optical elements downstream of source 201. In an embodiment, source 201 includes a Schottky source. Additionally or alternatively, source 201 may include a cold field emitter.

[0052] like Figure 4 As shown, in this embodiment, the electro-optics module 200 includes a plurality of electro-optical plate elements 24-26. The electro-optical plate elements 24-26 are configured to operate on a source beam. For example, the electro-optical plate elements 24-26 may help define one or more electromagnetic fields that influence the electrons of the source beam.

[0053] like Figure 4 As shown, in this embodiment, a plurality of beam apertures 266 are defined in the electron optics plate elements 24-26. The beam apertures 266 are configured for the passage of the source beam. Figure 4 As shown, in this embodiment, the beam aperture 266 is aligned with the transmitter 21.

[0054] like Figure 4 As shown, in one embodiment, source 201 includes a corresponding emitter 21. In another embodiment, the electron optics element includes an extractor arrangement 25. This extractor arrangement 25 is configured to operate on the source beam. In another embodiment, during operation, the emitter 21 is configured to emit electrons. These electrons can be extracted or accelerated by the extractor arrangement 25 to form the source beam 202.

[0055] like Figure 4 As shown, in this embodiment, at least one of the electron optical plate elements 24-26 is shared by the plurality of transmitters 21. Figure 4 As shown, in this embodiment, at least two of the electro-optical plate elements 24-26 are shared by a plurality of the transmitters 21. At least one of the electro-optical plate elements 24-26 is shared by all the transmitters 21 of the electro-optical module 200. Alternatively, at least one of the electro-optical plate elements 24-26 is shared by a subset of the transmitters 21 of the electro-optical module 200.

[0056] like Figure 4 As shown, in this embodiment, electron optical plate elements 24-26 extend across the source path of the source beam. Electron optical plate elements 24-26 may extend between adjacent emitters 21. Figure 4 As shown, in an embodiment, the electro-optical plate elements 24-26 may extend substantially perpendicular to the source path of the source beam emitted by the transmitter 21.

[0057] like Figure 4 As shown, in this embodiment, the electron optical plate elements 24-26 are substantially planar. The electron optical plate elements 24-26 may include a main planar surface. An electromagnetic field can be established between opposing surfaces. This electromagnetic field can affect the electrons in the source beam emitted by the transmitter 21.

[0058] Electro-optical elements 24-26 do not necessarily have to be completely planar. For example, one or more of the electron-optical elements 24-26 can be curved, such as bowl-shaped. Such a bowl-shaped electron-optical element has a plate-like shape.

[0059] In an embodiment, the extractor arrangement 25 is configured to operate individually on the source beam. The extractor arrangement 25 can help define one or more electromagnetic fields affecting electrons in the source beam. The extractor arrangement 25 can be configured such that at least one of the electromagnetic fields can be different for source beams from different emitters 21. For example, the extractor arrangement 25 can be arranged such that the amplitude and / or shape of the electromagnetic fields can be different for different source beams.

[0060] Embodiments of the present invention are intended to make it easier to align the emitters and extraction electrodes of multiple sources 201. Embodiments of the present invention are intended to reduce the time required to align the emitters and extraction electrodes of sources 201. For example, during the assembly of the electro-optics module 200, the emitters 21 can be aligned relative to the extractor arrangement 25. The sources 201 can then be integrated into the electro-optics device array 299, for example, as... Figure 3 As shown. By aligning the emitter 21 relative to the extractor arrangement 25 during the assembly of the electro-optics module 200, it is not necessary to align the emitter relative to the extraction electrode after the source 201 has been integrated into the electro-optics device array 299.

[0061] Embodiments of the present invention are intended to improve the accuracy of controlling the beam current of a source beam generated by multiple sources 201. By individually operating the source beam using the extractor arrangement 25, the beam current of the source beam can be controlled individually. For example, it is possible to provide multiple sources 201 that have more consistent beam currents with each other.

[0062] Figure 6 schematically depicted Figure 4 Plan view of the stack 23 of the electron optical plate elements 24-26 shown. Figure 7 A side view of the stack 23 of electron optical plate elements 24-26 is schematically depicted. Figure 7 The side view shown is along Figure 6 The cross-sectional view shown is captured by the dotted line.

[0063] like Figure 4 , Figure 6 and Figure 7 As shown, in this embodiment, the electro-optics module 200 includes a plurality of spacers 33, 36. The spacers 33, 36 are configured to space multiple of the electro-optics plate elements 24-26 apart from each other.

[0064] For example, in one embodiment, the electron optics plate element includes a suppressor 24. The suppressor 24 may be common to multiple emitters 21. The suppressor 24 may be configured to suppress any unwanted electron flow. Figure 4As shown, in this embodiment, the electron optics plate element includes an anode 26. For example, an emitter 21 may form a corresponding cathode. During operation, the emitter 21 can be configured to emit electrons. These electrons can be accelerated by the anode 26 to form the source beam. Figure 4 As shown, in this embodiment, the anode 26 is common to multiple transmitters 21. For example, Figure 4 The anode 26 shown is shared by the two sources 201 shown.

[0065] For example, Figure 4 A plurality of spacers 33 are schematically depicted, configured to space the suppressor 24 from the extractor arrangement 25. As another example, Figure 6 and Figure 7 A plurality of spacers 36 are schematically depicted, configured to space the suppressor 24 from the anode 26. In embodiments, other pairs of electro-optical plate elements are spaced apart from each other by one or more spacers. For example, in an embodiment, the electro-optical module 200 includes one or more spacers configured to space the extractor arrangement 25 from the anode 26.

[0066] In an embodiment, the electro-optical plate elements include one or more electro-optical plate elements in addition to the suppressor 24, the extractor arrangement 25, and the anode 26. In an embodiment, the suppressor 24 may be omitted. In an embodiment, the anode 26 may be omitted. In an embodiment, the electro-optical module 200 includes one or more spacers configured to space these other electro-optical plate elements apart from each other and / or space them apart from one or more of the suppressor 24, the extractor arrangement 25, and the anode 26.

[0067] like Figure 4 As shown, in an embodiment, each emitter 21 includes a tip 22. The emitter 21 is configured to emit electrons from the tip 22. Figure 4 As shown, in this embodiment, the tip 22 is located upstream of the extractor arrangement 25. Figure 4 As shown, in one embodiment, the tip 22 of the transmitter 21 extends through a beam aperture 266 defined in at least one of the electro-optical plate elements (e.g., suppressor 24). Figure 4 As shown, in an embodiment, the distance between the tip 22 of the transmitter 21 and the extractor arrangement 25 is less than the distance between the extractor arrangement 25 and an upstream electro-optical plate element (e.g., suppressor 24) of the extractor arrangement 25.

[0068] In this embodiment, spacers 33 and 36 are configured to mechanically support electron optical plate elements relative to each other. For example, spacers 33 and 36 may be fixed to electron optical plate elements 24-26. Electron optical plate elements 24-26 may be fixed relative to each other via spacers 33 and 36. Embodiments of the invention are intended to improve the mechanical stability of a plurality of sources 201, such as electrode stacks included within the plurality of sources. Additionally or alternatively, the electron optical module 200 may include one or more frames configured to mechanically support electron optical plate elements relative to each other. Such frames are optional. Spacers 33 and 36 may provide sufficient mechanical support for electron optical plate elements 24-26.

[0069] In this embodiment, spacers 33 and 36 are configured to electrically isolate the electro-optical plate elements 24-26 from each other. For example, spacers 33 and 36 may be arranged to provide a gap between adjacent electro-optical plate elements 24-26. Spacers 33 and 36 may comprise an electrically insulating material, such as quartz. Spacers 33 and 36 may be configured to reduce the likelihood of undesirable electrical breakdown between the electro-optical plate elements 24-26.

[0070] During operation of the electro-optics module 200, the electro-optics plate elements 24-26 can be maintained at different potentials. For example, one or more power supplies can be electrically connected to the electro-optics plate elements 24-26. The one or more power supplies can be configured to apply a potential to each of the electro-optics plate elements 24-26. For example, the controller 150 of the electro-optics device 140 can be configured to control one or more power supplies to control the potential of the electro-optics plate elements 24-26. Embodiments of the present invention are intended to reduce the possibility of unwanted electrical breakdown.

[0071] In an embodiment, spacers 33 and 36 are configured to mechanically support the extractor arrangement 25 in position relative to the beam path of the source beam. For example, spacer 33 may be configured to mechanically support the extractor arrangement 25 at a predetermined distance from the suppressor 24 for a corresponding source beam emitted from a corresponding transmitter 21. In an embodiment, spacers 33 and 36 are configured to mechanically support the extractor arrangement 25 in position individually relative to the beam path of the source beam, such that the extractor arrangement 25 is configured to operate on the source beam individually. By controlling the position of the extractor arrangement 25 relative to the beam path of the source beam, the extractor arrangement can affect the source beam differently for different source beams. Embodiments of the present invention are intended to improve the accuracy of beam current control for corresponding source beams.

[0072] In an embodiment, the extractor arrangement 25 includes a plurality of extractor electrodes 27, such as... Figure 4 As shown. In Figure 4In the illustrated arrangement, the extractor arrangement 25 includes an extractor electrode 27 for each emitter 21. The extractor electrodes 27 may be arranged in a common plane. The extractor arrangement 25 may form a layer comprising a plurality of extractor electrodes 27.

[0073] like Figure 6 As shown, in this embodiment, for each source beam, a plurality of spacers 33 are configured to mechanically support the extractor arrangement 25. By providing a plurality of spacers 33 to mechanically support the extractor arrangement 25, the orientation of the extractor arrangement 25 relative to the transmitter 21 can be controlled more precisely. For example, undesirable tilting of the extractor arrangement 25 relative to the transmitter 21 can be reduced.

[0074] like Figure 6 As shown, in this embodiment, for each source beam, at least three spacers 33 are configured to mechanically support the extractor arrangement 25. By providing at least three spacers 33, the orientation of the plate-like shape of the extractor arrangement 25 can be controlled relative to the transmitter 21. By providing three spacers 33, the plane of the extractor arrangement 25 can be controlled for each source beam. Figure 6 As shown, in one embodiment, only three spacers 33 are configured to mechanically support the extractor arrangement 25 for each source beam. In an alternative embodiment, more than three spacers 33 are provided to mechanically support the extractor arrangement 25 for each source beam.

[0075] like Figure 6 As shown, in one embodiment, the spacers 33 are evenly distributed circumferentially around the source path of each source bundle. In the case where more than three spacers 33 are provided for each source bundle, in this embodiment, the spacers 33 are arranged to be evenly distributed circumferentially around the source path.

[0076] like Figure 4 and Figure 6 As shown, for example, in one embodiment, the extractor arrangement 25 includes a plurality of extractor electrodes 27. As... Figure 6 As shown, the extractor electrodes 27 are separated from each other. The extractor electrodes 27 can be arranged such that a gap exists between adjacent extractor electrodes 27. Figure 6 In the arrangement shown, there are three extractor electrodes 27. In alternative embodiments, the number of extractor electrodes 27 is at least 5, optionally at least 10, optionally at least 20, optionally at least 50, optionally at least 100, optionally at least 200, optionally at least 500, and optionally at least 1000.

[0077] like Figure 6As shown, in this embodiment, each extractor electrode 27 is configured to operate on a different source beam. For example, each extractor electrode 27 can be configured to operate individually on a different source beam. By providing different extractor electrodes 27, the extractor electrodes can be individually controllable. For example, one or more power sources can be configured to apply different potentials to different extractor electrodes 27. By applying different potentials to different extractor electrodes 27, the source beams can be individually controlled. For example, the beam currents of different source beams output by different transmitters 21 can be individually controlled.

[0078] like Figure 6 As shown, in this embodiment, each extractor electrode 27 has a plurality of spacers 33. For example, as Figure 6 As shown, each extractor electrode 27 can have three spacers 33. By providing three spacers 33 for each extractor electrode 27, the plane of the extractor electrode 27 can be defined by the spacers 33. By providing three spacers 33 for each extractor electrode 27, the influence of the extractor electrode 27 on the source beam can be controlled more accurately and reliably.

[0079] like Figure 4 or Figure 7 As shown, for example, in one embodiment, spacer 33 is substantially planar. For example, spacer 33 may be disk-shaped. However, spacer 33 does not necessarily have to be substantially planar. For example, spacer 33 may have a dimension along the source path that is larger than the dimension of its cross-beam path. Figure 7 In this orientation, the spacer 33 may have a height that is at least as large as its width or larger than its width.

[0080] like Figure 7 As shown, in the embodiment, the spacer 33 is substantially parallel to one or more of the electron optical plate elements 24-26. For example, as Figure 7 As shown, spacer 33 may be substantially parallel to suppressor 24. In an embodiment, spacer 33 is substantially parallel to extractor arrangement 25 (e.g., parallel to extractor electrode 27 of extractor arrangement 25). In an embodiment, spacer 33 is substantially parallel to anode 26.

[0081] like Figure 6 As shown, in this embodiment, the spacers 33 have substantially similar shapes in at least two dimensions. For example, in a plan view, the spacers 33 may be circular. Alternatively, for example, in a plan view, the spacers 33 may be square or hexagonal. A plan view refers to a view along the source path of the source bundle. In this embodiment, the spacers 33 have substantially similar shapes in cross-section. In this embodiment, the spacers 33 have substantially the same dimensions in the direction across the source path.

[0082] like Figure 4 or Figure 7 As shown, in the embodiment, spacers 33 and 35 have edge profiles. For example, spacers 33 and 36 may include a radially inner portion 34 and a radially outer portion 35. The radially outer portion 35 is radially outside the radially inner portion 34. The radially inner portion 34 and the radially outer portion 35 may be integrally formed with each other.

[0083] like Figure 4 and Figure 7 As shown, in the embodiment, the radially inner portion 34 and the radially outer portion 35 may have different dimensions. For example, in the direction along the source path of the source bundle, the radially inner portion 34 may have a larger dimension than the radially outer portion 35. The radially inner portion 34 and the radially outer portion 35 may be arranged such that the spacers 33, 36 have edge profiles.

[0084] like Figure 7 As shown, for example, in one embodiment, the radially inner portion 34 is fixed to the surface of two adjacent electro-optical plate elements 24-26, which are spaced apart by spacers 33, 36. The radially outer portion 35 can be fixed to the surface of only one of the two electro-optical plate elements 24-26, where the spacers 33, 36 are configured to be spaced apart. Figure 7 As shown, in this embodiment, the radially outer portion 35 is fixed only to the upstream electro-optical plate element of the two electro-optical plate elements in which spacers 33 and 36 are configured to be spaced apart. For example, spacer 33 may have its radially outer portion 35 fixed only to suppressor 24. The radially outer portion 35 of spacer 33 may be spaced apart from extractor electrode 27 of extractor arrangement 25. Spacer 36 may have a radially outer portion 35 fixed only to suppressor 24. The radially outer portion 35 of spacer 36 may be spaced apart from anode 26.

[0085] like Figure 7 As shown, for example, in one embodiment, the edge profile has a path length on the surface above the edge that is greater than the thickness of the spacers 33, 36. By providing the edge profile, the possibility of unwanted electrical breakdown between the spaced-out electro-optical plate elements can be reduced.

[0086] like Figure 7 As shown, in one embodiment, the edge profile includes a step. This step provides an abrupt change in the dimensions of the spacers 33, 36 in the direction of the cross-source path. However, having a step in the edge profile is not mandatory. In an alternative embodiment, the edge profile may include gradually changing dimensions of the spacers 33, 36 in the direction of the cross-source path. By providing an edge profile including a step, the spacers 33, 36 may have stepped edges.

[0087] In one embodiment, the extractor arrangement 25 includes extractor electrodes 27 common to multiple source beams. For example, as Figure 4 or Figure 6 As shown, for example, extractor electrodes 27 can be coupled together to form a single integral plate. The resulting extractor electrodes can be shared by multiple source beams. By providing extractor electrodes 27 shared by multiple source beams to the extractor arrangement 25, the total number of components in the electro-optics module 200 can be reduced. The construction of the electro-optics module 27 can be simplified.

[0088] In one embodiment, the extractor arrangement 25 includes a plurality of extractor electrodes 27, each extractor electrode 27 being configured to operate on selection of a plurality of source beams. For example, each extractor electrode may be configured to operate on different plurality of source beams. In another embodiment, the extractor electrodes 27 are configured to operate on a corresponding source beam. For example, the extractor electrodes may be configured to operate on different individual source beams. The extractor electrodes 27 may be individually controllable. For example, the controller 150 may be configured to control one or more power supplies to individually control the potential applied to each extractor electrode 27. The potentials supplied to the different extractor electrodes 27 may be controlled independently of each other.

[0089] Figure 5 A partial enlarged view of the spacer 33 is schematically depicted. Figure 5 The spacer 33 shown is configured to separate the suppressor 24 from the extractor electrode 27. However, Figure 5 The features shown also apply to other types of spacers, such as spacer 36 configured to space the suppressor 24 from the anode 26.

[0090] like Figure 5 As shown, in one embodiment, the spacer 33 includes at least one mating surface 95. This mating surface 95 mats with one of the electro-optical plate elements 24-26. Figure 5 As shown, in this embodiment, the mating surface 95 is planar.

[0091] exist Figure 5 In the illustrated arrangement, spacer 33 includes two engagement surfaces 95. One engagement surface 95 engages with suppressor 24. The other engagement surface 95 engages with extractor electrode 27. In an alternative embodiment, spacer 33 may include a single-planar engagement surface 95 that engages with one of the electro-optical plate elements 24-26. For example, spacer 33 may be fixed to another electro-optical plate element via an alternative fixing mechanism or via a non-planar surface.

[0092] like Figure 5As shown, in this embodiment, spacer 33 is completely located between the two spaced-apart electro-optical plate elements. Spacer 33 is completely downstream of suppressor 24. Spacer 33 is completely upstream of extractor electrode 27.

[0093] By providing a planar interface surface 95, spacer 33 can space the electro-optical plate elements apart without excessively increasing the overall size of the electro-optical module 200. Embodiments of the present invention are intended to provide a more compact electro-optical module 200. The mating surface 95 can form the upstream and / or downstream surfaces of spacer 33.

[0094] like Figure 5 As shown, in an embodiment, the first of the two electro-optical plate elements is shared by a plurality of transmitters 21, wherein the spacer 33 is configured to space the two plate elements apart from each other. For example, in Figure 5 In the arrangement shown, the suppressor 24 is shared by the transmitter 21.

[0095] like Figure 5 As shown, in this embodiment, the second electro-optical element of the two electro-optical elements is separate for one of the transmitters 21. For example, in Figure 5 In the arrangement shown, the extractor electrode 27 may be a single one for one of the transmitters 21. Alternatively, the extractor electrode 27 may correspond to a subset of the transmitters 21, such as a group of transmitters 21, but not all of the transmitters 21.

[0096] In an alternative embodiment, the second electro-optical plate element may be shared by the same set of emitters 21 common to the first electro-optical plate elements. For example, when the spacer 36 separates the suppressor 24 from the anode 26, both the suppressor 24 and the anode 26 may be shared by a plurality of (e.g., the same plurality of) emitters 21. The plurality of emitters 21 may be all emitters 21.

[0097] exist Figure 5 In the arrangement shown, the first electron optical plate element can be located upstream of the spacer 33. Figure 5 In the middle, the upstream direction is upward. The second electron optical plate element can be located downstream of spacer 33. Figure 5 In the middle and downstream directions, the flow is downward. For example... Figure 7 As shown, in this embodiment, a second electro-optical plate element (e.g., extractor arrangement 25) is located between a first electro-optical plate element (e.g., suppressor 24) and a third electro-optical plate element (e.g., anode 26). A spacer 33 is configured to fix the position of the electro-optical plate element, which is located at a central position within the stack 23.

[0098] like Figure 7As shown, in this embodiment, the second electro-optical plate element (e.g., extractor arrangement 25) and the third electro-optical plate element (e.g., anode 26) are fixed to each other indirectly only via at least one other of the plurality of electro-optical plate elements (e.g., suppressor 24). In other words, as Figure 7 As shown, no spacers are required between each pair of adjacent electro-optical elements in stack 23. For example, a spacer separating the extractor arrangement 25 from the anode 26 is not required. In an alternative embodiment, another spacer is provided to space the extractor arrangement 25 from the anode 26.

[0099] By omitting the spacer between the extractor arrangement 25 and the anode 26, undesirable mechanical stresses in the electro-optics module 200 can be reduced. For example, if spacers are provided between each pair of adjacent electro-optic elements in the stack 23, the position of a given electro-optic element can be determined by multiple different mechanical connections. For example, when spacers separate the extractor arrangement 25 from the anode 26, the position of the anode 26 can be defined by spacers 33, 36 relative to two different components. The position of the anode 26 can be determined by spacer 36 relative to the suppressor 24. The position of the anode 26 can also be determined by another spacer relative to the extractor arrangement 25. This may cause the position of the anode 26 to be out of control. This may cause undesirable stresses in the electro-optics module 200. Any undesirable stresses can cause undesirable deformation of the electro-optics module 200. Embodiments of the present invention are intended to improve the reliability of the electro-optics module 200.

[0100] like Figure 7 As shown, in an embodiment, the first electro-optical plate element (e.g., suppressor 24) and the third electro-optical plate element (e.g., anode 26) are spaced apart from each other by spacer 35.

[0101] In an embodiment, one of the electro-optical plate elements spaced apart by the spacers 33 is configured to individually control the current density of a corresponding source beam. For example, one of the electro-optical plate elements may be the extractor arrangement 25. The extractor arrangement 25 may be configured to individually control the current density of a corresponding source beam. For example, the extractor arrangement 25 may include a plurality of extractor electrodes 27. Each extractor electrode 27 may be configured to control the current density of an individual source beam.

[0102] Figure 8 An electro-optical module according to an alternative embodiment is schematically depicted. Figure 8 As shown, in this embodiment, the electro-optics module includes a single source 201. It is not necessary for the electro-optics module to include multiple sources 201.

[0103] like Figure 8As shown, in this embodiment, the electro-optical module includes a single transmitter 21. The transmitter 21 is configured to emit an electron source beam. Figure 8 As shown, in this embodiment, the electro-optical module includes a plurality of electro-optical plate elements 24-26.

[0104] Figure 8 Some of the features shown are described elsewhere with reference to other accompanying drawings. These features may be described elsewhere as well. For example, emitter 21, suppressor 24, extractor electrode 27, anode 26, and spacers 33, 36 may be described, for example, with reference to Figure 4-7 As described.

[0105] like Figure 8 As shown, the electro-optical module including a single source 201 may include spacers 33, 36, and the spacers 33, 36 include at least one mating surface (e.g., particularly referring to...). Figure 5 (As described elsewhere).

[0106] like Figure 5 As shown, in this embodiment, the bonding surface 95 is substantially parallel to the electro-optical plate element to which the bonding surface 95 is bonded. For example, the upstream bonding surface 95 may be substantially parallel to the suppressor 24. The downstream bonding surface 95 may be substantially parallel to the extractor electrode 27 or the anode 26.

[0107] like Figure 5 As shown, in one embodiment, the spacer 33 includes an insulating surface 94. The insulating surface 94 is located between two electro-optical plate elements spaced apart from each other by the spacer 33. For example, in Figure 5 In the arrangement shown, the insulator surface 94 is located between the suppressor 24 and the extractor electrode 27 of the extractor arrangement 25. In an alternative embodiment, the insulator surface 94 of the spacer 36 may be located between the suppressor 24 and the anode 26.

[0108] In one embodiment, at least a portion of the insulator surface 94 is angled relative to a direction perpendicular to the two electron optical plate elements. Figure 5 In the middle, the direction perpendicular to the two electron optical plate elements is the vertical direction. Figure 5 The insulator surface 94 shown includes a portion that extends substantially parallel to the electron optical plate element. This is due to... Figure 5 The horizontal line in the diagram represents the insulator surface 94 (i.e., the surface of spacer 33 other than the mating surface 95). Specifically, Figure 5 The downstream end of the radially outer portion 35 is shown to be substantially parallel to the electron optical plate element.

[0109] like Figure 5As shown, in this embodiment, the insulator surface 94 includes at least a portion perpendicular to the direction of the two electron optical elements. For example, the radially outer edge of the radially outer portion 35 is substantially perpendicular to the two electron optical elements. However, not all of the insulator surface 94 needs to be perpendicular to the electron optical elements.

[0110] like Figure 4 As shown, for example, in one embodiment, the electro-optical module 200 includes a plurality of spacers 33 arranged in a common plane. In one embodiment, each spacer 33 includes at least one planar engagement surface 95.

[0111] For example, Figure 4 , Figure 6 , Figure 7 and Figure 8 As shown, in this embodiment, spacers 33 and 36 are spaced apart from beam aperture 266. Beam aperture 266 is defined within two electron optical plate elements. In this embodiment, spacers 33 and 36 are separated from beam aperture 266 by at least a threshold distance. By providing a minimum threshold distance, the possibility of electrons from the source beam generating undesirable charges on the surfaces of spacers 33 and 36 can be reduced.

[0112] like Figure 6 As shown, for example, in one embodiment, the spacer 33 is positioned at substantially the same distance from the beam aperture 266. For example, Figure 6 Each beam aperture 266 is shown to have three associated spacers 33. These three spacers 33 are located at the same distance from the beam aperture 266. In an embodiment, the spacers 33 are arranged such that adjacent spacers 33 are spaced substantially the same distance from each other.

[0113] like Figure 4 As shown, for example, in an embodiment, at least one of the electron optics elements includes a feature located between the beam aperture 266 and the spacer 33. This feature is configured to reduce the number of electrons reaching the spacer 33 from the beam aperture 266. For example, electron absorbers 41 and 42 are examples of such features.

[0114] like Figure 8 As shown, in one embodiment, the electro-optical module 200 includes a shield 37. The shield 37 may be a field shield. In one embodiment, the shield 37 is configured to shield the emitter 21. For example, the shield 37 may be configured to shield the emitter 21 from external electromagnetic fields.

[0115] like Figure 4 , Figure 6 and Figure 7As shown, in one embodiment, a vent 46 is defined in one or more of the electro-optical plate elements 24-26. The vent 46 is separate from the beam aperture 266 defined in the electro-optical plate elements 24-26. In another embodiment, multiple vents 46 are defined in one or more of the electro-optical plate elements 24-26.

[0116] like Figure 6 As shown, in this embodiment, the vents 46 defined in different electro-optical plate elements 24-26 can be aligned with each other, for example, in the direction along the source path. Figure 6 The three vents 46 closest to the center of stack 23, shown in the diagram, are aligned along the source path in both the suppressor 24 and the anode 26. In an embodiment, one or more vents 46 are provided that extend only partially through stack 23. For example, as... Figure 7 As shown, the vent 46, located on the right side of the figure, is confined within the suppressor 24 but is not aligned with the corresponding vent in the anode 26. This vent may be referred to as a vent hole.

[0117] In an embodiment, the vent 46 is configured to provide gas conduction through the electro-optical plate elements 24-26. Each electro-optical plate element does not necessarily have at least one vent 46 defined therein. For example, as... Figure 7 As shown, in this embodiment, the extractor arrangement 25 is not limited to a vent therein. The extractor arrangement 25 may have a beam aperture 266 defined therein. In this embodiment, the beam aperture 266 is the only aperture or hole defined in the extractor electrode 27 of the extractor arrangement 25. By providing a vent, gas conduction through the stack 23 can be increased. The beam aperture 266 can provide some gas conduction through the stack 23; by providing a vent 46, gas conduction can be increased compared to the case where only the beam aperture 266 is provided for gas conduction.

[0118] In one embodiment, the gas conduction is used to maintain a vacuum within the electro-optics module 200. For example, in one embodiment, the pressure within the electro-optics module 200 is maintained lower than the pressure in one or more volumes within the electro-optics device 140 outside the electro-optics module 200. It is desirable to increase the gas conduction through the stack 23 so that this low pressure can be maintained.

[0119] Figure 9 A portion of the electro-optical device 140 is schematically depicted. (As shown) Figure 9As shown, in one embodiment, the emitter 21 and stack 23 of the electron optics module 200 are located within a vacuum chamber 60. In one embodiment, a vacuum device 61 is provided to maintain a vacuum in the emitter 21. In one embodiment, the vacuum device 61 includes an ion pump. In one embodiment, the vacuum device includes one or more getter devices. In one embodiment, the vacuum device 61 is configured to receive gas from the volume containing the emitter 21. The vacuum device 61 may be configured to prevent gas backflow toward the emitter 21. In one embodiment, a magnetic shield 62 is provided between the vacuum device 61 and the emitter 21.

[0120] like Figure 9 As shown, in an embodiment, the electro-optical device 230 may include electro-optical elements located downstream of the source 201. For example, in an embodiment, one or more deflector arrays 235 and / or one or more collimator arrays 260 may be provided downstream of the source 201. In an embodiment, the electro-optical elements are provided in a volume different from the volume in which the source 201 is located. In an embodiment, the different volumes are maintained at different pressures. In an embodiment, the electro-optical elements define a boundary between two different volumes maintained at different pressures.

[0121] For example, in one embodiment, the source 201, including emitter 21 and stack 23, is located in a volume maintained under vacuum pressure. In one embodiment, converging array 231 defines a downstream boundary of the volume containing source 201. In one embodiment, a volume immediately downstream of converging array 231 can be maintained at a different pressure. Converging array 231 can define an upstream boundary of this volume. Figure 9 As shown, in an embodiment, a vacuum pump 63 and / or a valve (e.g., a rotary valve) defines the downstream end of the volume.

[0122] In one embodiment, valve 64 defines the upstream boundary of a volume containing deflector array 235. The downstream end of this volume may be defined by collimator array 260. The volume containing deflector array 235 can be maintained at different pressures independently of other volumes. In another embodiment, collimator array 260 defines the upstream end of another volume. The downstream end of this volume may be defined by objective lens array 234 and / or detector 240. This volume can be maintained at different pressures independently of other volumes.

[0123] like Figure 4As shown, in one embodiment, the electro-optics module 200 includes a converging array 231. In this embodiment, a converging array 231 is provided for each emitter 21. The converging array 231 can be considered part of the electro-optics module 200. For example, during assembly of the electro-optics module 200, the converging array 231 can be fixed to the stack 23 of the electro-optics module 200. Before the electro-optics module 200 is incorporated into the electro-optics device 230 or the electro-optics apparatus 140, the converging array 231 can be fixed relative to the plurality of emitters 21. Alternatively, the converging array 231 can be omitted from the electro-optics module 200. After the electro-optics module 200 has been incorporated into the electro-optics device 230 or the electro-optics apparatus 140, the converging array 231 of the electro-optics device 230 can be fixed relative to the emitters 21.

[0124] like Figure 4 As shown, in one embodiment, the electro-optics module 200 includes a converging frame 32. The converging frame 32 is configured to secure the converging array 231 to the stack 23. In one embodiment, a plurality of converging frames 32 are provided for securing a respective converging array 231 to a respective emitter 21.

[0125] like Figure 4 As shown, in this embodiment, the convergent array 231 is fixed to the downstream element of the stack 23. For example, as Figure 4 As shown, in this embodiment, the downstream element of the stack 23 is the anode 26. In this embodiment, the converging frame 32 is configured to secure the anode 26 to the converging array 231. For example, the converging frame 32 may be directly secured to both the anode 26 and the converging array 231. The converging frame 32 is configured to fix the position of the converging array 231 relative to the stack 23.

[0126] like Figure 4 As shown, in an embodiment, the electron optics module 200 includes one or more electron absorbers 41, 42. For example, an electron absorber 41 may be provided at the surface of the anode 26. For example, multiple electron absorbers 41 may be provided at the upstream surface of the anode 26. In an embodiment, an electron absorber 42 is provided at the surface of the extractor arrangement 25. For example, the electron absorber 42 may be located at the downstream surface of the extractor arrangement 25.

[0127] like Figure 4 As shown, in this embodiment, an electron absorber 41 is provided corresponding to each emitter 21 at the anode 26. An electron absorber 42 may be provided for each emitter 21 at the extractor arrangement 25. In this embodiment, when viewed in plan view (i.e., when viewed along the source path), the electron absorbers 41, 42 are formed substantially around the source path. For example, the electron absorbers 41, 42 may form a ring.

[0128] In one embodiment, one or more electron absorbers are provided at the upstream surface of the extractor arrangement. In another embodiment, one or more electron absorbers are located at the downstream surface of the suppressor 24.

[0129] In this embodiment, electron absorbers 41 and 42 are configured to reduce the electron flow in a radially outward direction from the source path. Electron absorbers 41 and 42 are not necessarily formed as rings. In alternative arrangements, when viewed in plan view (i.e., along the beam path), electron absorbers 41 and 42 may include multiple arcs or multiple elongated portions.

[0130] like Figure 4 As shown, in this embodiment, a recess 49 may be provided on the surface facing (or opposite) the electron absorbers 41, 42. For example, a recess 49 may be provided in the downstream surface of the extractor arrangement 25 opposite to the electron absorber 41. Similarly, a recess 49 may be provided on the upstream surface of the anode 26 opposite to the electron absorber 42 provided on the downstream surface of the extractor arrangement 25. By providing the recess, the dimensions of the gaps between adjacent electron optical plate elements can be made more consistent in the direction of the beam path. By making the gap dimensions more consistent, the amplitude of the electric field can be more consistent. Undesirable peak values ​​of the electromagnetic field amplitude can be reduced. By avoiding high peak values ​​in the electromagnetic field amplitude, the possibility of undesirable electrical breakdown can be reduced.

[0131] By reducing the radial outward flow of electrons from the source path, the likelihood of parts of the source module 200 becoming undesirably charged can be reduced. For example, the likelihood of spacers 33 and 36 becoming undesirably charged can be reduced. By reducing the charging of components with spacers 33 and 36, the likelihood of undesirable electrical breakdown can be reduced.

[0132] like Figure 4 As shown, for example, in this embodiment, the elements of the electro-optical module 200 are aligned. For example, the elements of the electro-optical module 200 may be aligned prior to assembly. Alignment may be performed before the electro-optical module 200 is incorporated as part of the electro-optical device 140 or the electro-optical apparatus 230. Further alignment may be performed to align the electro-optical module 200 with respect to other electro-optical elements of the electro-optical device 230 or the electro-optical device 140.

[0133] like Figure 3 As 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.

[0134] In an embodiment, each electro-optical device 230 includes an electro-optical element located 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.

[0135] 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.

[0136] 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, thus it can be considered an electro-optical element.

[0137] Another embodiment of the invention is presented in the following numbered clauses: 1. 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 corresponding beam path, the charged particle optical module comprising: Multiple emitters are configured to emit source beams of corresponding charged particles; A plurality of charged particle optical plate elements are configured to operate on the source beam and define a plurality of beam apertures for the passage of the source beam; wherein at least one of the charged particle optical plate elements is common to the plurality of emitters; and A spacer is configured to space two of the charged particle optical plate elements apart from each other, wherein the spacer includes at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar. 2. The charged particle optical module according to Clause 1, wherein the spacer is configured such that the first charged particle optical plate element of the two charged particle optical plate elements spaced apart from each other is shared by the plurality of said emitters. 3. The charged particle optical module according to Clause 2, wherein the second charged particle optical plate element of the two charged particle optical plate elements is separate for one of the emitters. 4. The charged particle optical module according to Clause 2, wherein the second charged particle optical plate element of the two charged particle optical plate elements is shared by a subset of the emitters shared by the first charged particle optical plate elements. 5. The charged particle optical module according to clause 3 or 4, wherein the second charged particle optical plate element is located between the first charged particle optical plate element and the third charged particle optical plate element of the plurality of charged particle optical plate elements. 6. The charged particle optical module according to Clause 5, wherein the second charged particle optical plate element and the third charged particle optical plate element are fixed to each other only indirectly via at least one other charged particle optical plate element among the plurality of charged particle optical plate elements. 7. The charged particle optical module according to Clause 5 or 6, wherein the first charged particle optical plate element and the third charged particle optical plate element are spaced apart from each other by spacers. 8. The charged particle optical module according to any of the foregoing clauses, wherein one of the charged particle optical plate elements is configured to individually control the current density of the respective source beam. 9. A charged particle optical module for a charged particle optical device configured to guide a charged particle beam toward a sample location along a corresponding beam path, the charged particle optical module comprising: The transmitter is configured to emit a source beam of charged particles; Multiple charged particle optical plate elements are configured to operate on the source beam and define multiple beam apertures for the passage of the source beam; and A spacer is configured to space two of the charged particle optical plate elements apart from each other, wherein the spacer includes at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar. 10. The charged particle optical module according to any of the preceding clauses, wherein the bonding surface is substantially parallel to the charged particle optical plate element to which the bonding surface is bonded. 11. The charged particle optical module according to any of the preceding clauses, wherein the bonding surface is at the upstream or downstream end of the spacer. 12. The charged particle optical module according to any of the preceding clauses, wherein the spacer includes two engagement surfaces that engage with two charged particle optical plate elements, the two charged particle optical plate elements being spaced apart from each other by the spacer. 13. The charged particle optical module according to any of the preceding clauses, wherein the spacer includes an insulating surface between the two charged particle optical plate elements spaced apart by the spacer, wherein at least a portion of the insulating surface is angled relative to a direction perpendicular to the two charged particle optical plate elements. 14. The charged particle optical module according to Clause 13, wherein the insulator surface is stepped. 15. The charged particle optical module according to any of the preceding clauses, wherein the spacer is planar. 16. The charged particle optical module according to Clause 15, wherein the spacer is substantially disk-shaped. 17. A charged particle optical module according to any of the preceding clauses, comprising a plurality of spacers, each spacer configured to space the two identical charged particle optical plate elements apart from each other, and comprising at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar. 18. The charged particle optical module according to Clause 17, wherein the spacers are arranged in a common plane. 19. The charged particle optical module according to Clause 17 or 18, wherein the spacer is at least a threshold distance from the beam aperture defined in the two charged particle optical plate elements. 20. A charged particle optical module according to any one of clauses 17-19, wherein the spacer is at substantially the same distance from the beam aperture defined by the two charged particle optical plate elements. 21. The charged particle optical module according to any one of clauses 17-20, wherein the spacers are arranged such that adjacent spacers are spaced substantially the same distance from each other. 22. A charged particle optical module according to any of the preceding clauses, wherein a vent is defined in one or more of the charged particle optical plate elements, the vent being configured to provide gas conduction through the charged particle optical plate elements for maintaining a vacuum within the charged particle optical module. 23. The charged particle optical module according to any of the preceding clauses, wherein at least one of the charged particle optical plate elements includes a feature located between the beam aperture and the spacer, the feature being configured to reduce charged particles reaching the spacer from the beam aperture. 24. The charged particle optical module according to any of the preceding clauses, wherein the charged particle optical plate element includes an anode. 25. The charged particle optical module according to any of the preceding clauses, wherein the charged particle optical plate element includes a suppressor. 26. The charged particle optical module according to any of the preceding clauses, wherein the charged particle optical plate element includes an extractor arrangement. 27. The charged particle optical module according to any of the preceding clauses, wherein the beam apertures of different charged particle optical plate elements are aligned with respect to the corresponding emitters. 28. At least one charged particle optical device configured to guide a charged particle beam toward a sample location along a corresponding beam path, said at least one charged particle optical device comprising a charged particle optical module as described in any of the preceding clauses. 29. A charged particle optical device, comprising: The charged particle optical device described in Clause 28; and An actuable stage is configured to support the sample at the sample location. 30. An evaluation apparatus for evaluating samples, comprising: Vacuum chamber; and The charged particle optical device described in Clause 29, wherein the charged particle optical device is located in a vacuum chamber. 31. A method for operating a charged particle optical module, the charged particle optical module being used in a charged particle optical device, the charged particle optical device being configured to guide a charged particle beam toward a sample location along a corresponding beam path, the method comprising: A source beam of charged particles is emitted from a corresponding emitter; and The source beam is operated using a plurality of charged particle optical plate elements, the charged particle optical plate elements defining a plurality of beam apertures through which the source beam passes, wherein at least one of the charged particle optical plate elements is shared by a plurality of the emitters; The two of the charged particle optical plate elements are spaced apart from each other by a spacer, wherein the spacer includes at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar. 32. A method for operating a charged particle optical module, the charged particle optical module being used in a charged particle optical device, the charged particle optical device being configured to guide a charged particle beam toward a sample location along a corresponding beam path, the method comprising: A source beam of charged particles emitted from the transmitter; and The source beam is operated using a plurality of charged particle optical plate elements, which define a plurality of beam apertures for the passage of the source beam. The two of the charged particle optical plate elements are spaced apart from each other by a spacer, wherein the spacer includes at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar.

[0138] 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).

[0139] 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 in a charged particle optical device configured to guide a charged particle beam toward a sample location along a corresponding beam path, the charged particle optical module comprising: The transmitter is configured to emit a source beam of charged particles; A plurality of charged particle optical plate elements are configured to operate on the source beam and define a plurality of beam apertures for the passage of the source beam; as well as A spacer is configured to space two of the charged particle optical plate elements apart from each other, wherein the spacer includes at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar.

2. The charged particle optical module according to any one of the preceding claims, wherein the bonding surface is substantially parallel to the charged particle optical plate element bonded to the bonding surface.

3. The charged particle optical module according to any one of the preceding claims, wherein the bonding surface is at the upstream or downstream end of the spacer.

4. The charged particle optical module according to any one of the preceding claims, wherein the spacer includes two bonding surfaces that are bonded to two charged particle optical plate elements spaced apart from each other by the spacer.

5. The charged particle optical module according to any one of the preceding claims, wherein the spacer includes an insulating surface between two charged particle optical plate elements spaced apart by the spacer, wherein at least a portion of the insulating surface is angled relative to a direction perpendicular to the two charged particle optical plate elements.

6. The charged particle optical module according to claim 5, wherein the insulator surface is stepped.

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

8. The charged particle optical module of claim 7, wherein the spacer is substantially disk-shaped.

9. The charged particle optical module according to any one of the preceding claims, comprising a plurality of spacers, each spacer configured to space two identical charged particle optical plate elements apart from each other, and comprising at least one engagement surface that engages with one of the charged particle optical plate elements, the engagement surface being planar.

10. The charged particle optical module of claim 9, wherein the spacers are arranged in a common plane.

11. The charged particle optical module according to claim 9 or 10, wherein the spacer is at least a threshold distance from the beam aperture defined in the two charged particle optical plate elements.

12. The charged particle optical module according to any one of claims 9 to 11, wherein the spacer is at substantially the same distance from the beam aperture defined by the two charged particle optical plate elements.

13. The charged particle optical module according to any one of claims 9 to 12, wherein the spacers are arranged such that adjacent spacers are spaced substantially the same distance from each other.

14. The charged particle optical module according to any one of the preceding claims, wherein a vent is defined in one or more of the charged particle optical plate elements, the vent being configured to provide gas conduction through the charged particle optical plate elements for maintaining a vacuum within the charged particle optical module.

15. The charged particle optical module according to any one of the preceding claims, wherein at least one of the charged particle optical plate elements includes a feature located between the beam aperture and the spacer, the feature being configured to reduce charged particles reaching the spacer from the beam aperture.

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