Multi-source illumination device

Abstract

Disclosed herein is a multi-source illumination apparatus for illuminating a sample using charged particles, the apparatus comprising a plurality of sources (401), each arranged to emit a beam of charged particles; a condenser lens (403) arranged to receive beams from the plurality of sources; and a manipulator array arrangement (404, 405) configured to receive beams that have passed through the condenser lens. The beams are arranged such that, at the plane of the condenser lens, a beam from at least one source intersects at least a portion of another beam from a different one of the plurality of sources. The condenser lens is configured to separately substantially collimate the beams received from each source. The manipulator array arrangement is configured to manipulate the beams that have been substantially collimated by the condenser lens to generate one or more beams comprising charged particles from the plurality of sources in the form of a single column. The manipulator array arrangement comprises a deflector array (404) arranged to deflect the beams that have been substantially collimated by the condenser lens to generate a plurality of substantially parallel substantially collimated beams comprising charged particles from the plurality of sources, and a multi-beam generator (405) configured to: receive the plurality of substantially parallel substantially collimated beams generated by the deflector array; and generate, from the received plurality of substantially parallel substantially collimated beams, a multi-beam, wherein the multi-beam comprises a plurality of substantially collimated sub-beams.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to EP19212139.0, filed on November 28, 2019, and EP20189242.9, filed on August 3, 2020, which are each incorporated herein by reference in their entirety. Technical Field

[0003] The embodiments provided herein generally relate to a charged particle irradiation device, and more specifically to a charged particle beam irradiation device, including more than one charged particle source. Background Technology

[0004] When manufacturing semiconductor integrated circuit (IC) chips, undesirable pattern defects inevitably occur on the substrate (i.e., wafer) or mask during the manufacturing process due to factors such as optical effects and adjunct particles, thus reducing yield. Therefore, monitoring the extent of undesirable pattern defects is a crucial process in IC chip manufacturing. More generally, the inspection and / or measurement of the surface of the substrate or other objects / materials are input processes during and / or after their manufacturing.

[0005] Pattern inspection tools with charged particle beams have been used to inspect objects, for example, to detect pattern defects. These tools typically employ electron microscopy techniques, such as scanning electron microscopy (SEM). In SEM, a primary electron beam of relatively high-energy electrons targets a final deceleration step to land on the sample with a relatively low landing energy. The electron beam is focused on the sample as a probe point. The interaction between the material structure at the probe point and the landing electrons from the electron beam causes electrons to be emitted from the surface, such as secondary electrons, backscattered electrons, or Auger electrons. The generated secondary electrons can be emitted from the material structure of the sample. By scanning the primary electron beam, which serves as the probe point, across the sample surface, secondary electrons can be emitted. By collecting these emitted secondary electrons from the sample surface, the pattern inspection tool can obtain an image representing the characteristics of the material structure of the sample's surface.

[0006] Another application of charged particle beams is photolithography. The charged particle beam reacts with a resist layer on the surface of a substrate. By controlling the position of the charged particle beam on the resist layer, desired patterns can be created within the resist.

[0007] There is often a need to improve the generation of charged particle beams for use in electron microscopy and other applications, such as photolithography. Summary of the Invention

[0008] The embodiments provided herein disclose a charged particle beam irradiation apparatus. The charged particle beam irradiation apparatus can be used to generate multiple beams of charged particles. The charged particle beam irradiation apparatus can be included within an inspection apparatus or a photolithography apparatus.

[0009] According to a first aspect of the invention, a multi-source irradiation apparatus for irradiating a sample with charged particles is provided, the apparatus comprising a plurality of sources, each arranged to emit a beam of charged particles; a condenser lens arranged to receive the beams from the plurality of sources; and a manipulator array arrangement configured to receive the beams that have passed through the condenser lens; wherein the beams are arranged such that, at the plane of the condenser lens, a beam from at least one source intersects at least a portion of another beam from a different source among the plurality of sources; the condenser lens is configured to separately and substantially collimate the beams received from each source; and the manipulator array arrangement is configured to manipulate the beams that have been substantially collimated by the condenser lens, thereby generating one or more beams comprising charged particles from the plurality of sources in a single column.

[0010] According to a second aspect of the invention, a multi-beam inspection tool is provided, comprising a multi-source irradiation device according to the first aspect, wherein the multi-source irradiation device is arranged to irradiate a sample; and a detector arranged to detect charged particles received from the irradiated sample.

[0011] According to a third aspect of the invention, a multi-beam lithography tool is provided, comprising a multi-source irradiation device according to a first aspect, wherein the multi-source irradiation device is arranged to irradiate a resist on a substrate.

[0012] According to a fourth aspect of the invention, a multi-source irradiation apparatus for generating multiple beams of charged particles is provided, the apparatus comprising a plurality of sources, each arranged to emit a beam of charged particles; and a manipulator array arrangement including a beam input and a beam output; wherein the beam input is configured to receive beams from the plurality of sources; the beams are arranged such that at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, the irradiation area of ​​each beam is substantially adjacent to the irradiation area of ​​one or more other beams; and the manipulator array arrangement is configured to output multiple beams of charged particles from a single-row beam output.

[0013] According to a fifth aspect of the invention, a method is provided for generating one or more charged particle beams for irradiating a sample, the method comprising: emitting charged particle beams through each of a plurality of sources such that the beams at least partially intersect; substantially collimating the beams from each source at a location where the beams at least partially intersect along the optical axes of the charged particles; and manipulating the substantially collimated beams to generate one or more beams comprising charged particles from the plurality of sources in a single column.

[0014] According to a sixth aspect of the invention, a multi-source irradiation apparatus for irradiating a sample with charged particles is provided, the apparatus comprising a plurality of sources; a condenser lens arrangement configured to receive charged particle beams from each source and to collimate the beams from each source separately and substantially separately; at least one source beam manipulator arrangement, wherein each source beam manipulator arrangement is arranged between a source and the condenser lens arrangement and configured to operate on the beam therebetween; and a manipulator array arrangement configured to receive beams that have passed through the condenser lens arrangement and to generate a single multi-beam charged particle from the plurality of sources.

[0015] Other advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which certain embodiments of the invention are illustrated by way of description and example. Attached Figure Description

[0016] The above and other aspects of this disclosure become more apparent from the description of exemplary embodiments taken in conjunction with the accompanying drawings.

[0017] Figure 1 This is a schematic diagram illustrating an exemplary charged particle beam inspection device.

[0018] Figure 2 It is illustrated as Figure 1 A schematic diagram of an exemplary multi-beam device, which is a part of an exemplary charged particle beam inspection apparatus.

[0019] Figure 3 It's a diagram. Figure 1 A schematic diagram of an exemplary multi-beam device with an exemplary configuration of the source conversion unit of an exemplary charged particle beam inspection apparatus.

[0020] Figure 4 It is a multi-source irradiation device according to the embodiment.

[0021] Figure 5 This is a flowchart of a process according to an embodiment.

[0022] Figure 6 It is a multi-source irradiation device according to the embodiment.

[0023] Figure 7 It is part of the multi-source irradiation apparatus according to the embodiment.

[0024] Figure 8 It is part of the multi-source irradiation apparatus according to the embodiment.

[0025] Figure 9A and Figure 9B Different configurations of the multi-source irradiation apparatus according to embodiments are shown.

[0026] Figure 10A and Figure 10B Different configurations of the multi-source irradiation apparatus according to embodiments are shown.

[0027] Figure 11 Several different implementations of portions of a multi-source irradiation apparatus according to an embodiment are shown.

[0028] Figure 12 It is a multi-source irradiation device according to the embodiment.

[0029] Figure 13 It is a multi-source irradiation device according to the embodiment.

[0030] Figure 14 It is part of the multi-source irradiation apparatus according to the embodiment.

[0031] Figure 15 It is a multi-source irradiation device according to the embodiment.

[0032] Figure 16 It is part of the multi-source irradiation apparatus according to the embodiment.

[0033] Figure 17 It is part of the multi-source irradiation apparatus according to the embodiment.

[0034] Figure 18 It is part of the multi-source irradiation apparatus according to the embodiment.

[0035] Figure 19 It is part of the multi-source irradiation apparatus according to the embodiment. Detailed Implementation

[0036] Now, reference will be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, wherein, unless otherwise stated, the same reference numerals in different drawings denote the same or similar elements. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with the aspects of the invention as described in the appended claims.

[0037] The computing power of electronic devices can be enhanced by significantly increasing the packaging density of circuit components (such as transistors, capacitors, diodes, etc.) on IC chips (which reduces the physical size of the device). This has been achieved by increasing resolution, making it possible to manufacture even smaller structures. For example, the IC chip for a smartphone can include more than 2 billion transistors, each smaller than 1 / 1000th the size of a human hair; this IC chip is the size of a thumbnail and was available in 2019 or earlier. Therefore, it is not surprising that semiconductor IC manufacturing is a complex and time-consuming process with hundreds of separate steps. Even an error in one step can significantly affect the functionality of the final product. A single “fatal defect” can cause a device to fail. The goal of a manufacturing process is to increase the overall process yield. For example, for a 50-step process (where one step can indicate the number of layers formed on the wafer), to achieve a 75% yield, the yield of each individual step must be greater than 99.4%. If the yield of a single step is 95%, the overall process yield will be as low as 7%.

[0038] While high process yields are required in IC chip manufacturing equipment, maintaining high substrate (i.e., wafer) yields (defined as the number of substrates processed per hour) is also essential. The presence of defects can impact both high process yields and high substrate yields, especially when operator intervention is required to inspect for defects. Therefore, high-throughput detection and identification of micron- and nanometer-scale defects using inspection tools such as scanning electron microscopy (“SEM”) is necessary to maintain both high yields and low costs.

[0039] A Sequencing Array (SEM) comprises a scanning device and a detector device. The scanning device includes an illumination device and a projection device. The illumination device includes an electron source for generating primary electrons, and the projection device is used to scan a sample, such as a substrate, using one or more focused beams of primary electrons. The primary electrons interact with the sample and generate secondary electrons. During sample scanning, the detector device captures these secondary electrons from the sample, allowing the SEM to produce an image of the scanned area of ​​the sample. For high-throughput inspection, some inspection devices use multiple focused beams of primary electrons, i.e., multi-beam primary electrons. The component beams of a multi-beam array can be referred to as sub-beams or beam waves. Multi-beam arrays can scan different portions of the sample simultaneously. Therefore, multi-beam inspection devices are able to inspect samples at much higher speeds than single-beam inspection devices.

[0040] In multi-beam inspection apparatuses, some primary electron beams deviate from the central axis of the scanning apparatus (i.e., the midpoint of the primary electron optical axis). To ensure that all electron beams reach the sample surface at substantially the same incident angle, sub-beam paths with a greater radial distance from the central axis need to be manipulated, moving through a larger angle compared to sub-beam paths closer to the central axis. This stronger manipulation can lead to aberrations that result in blurred and out-of-focus images of the sample substrate. In particular, for sub-beam paths not on the central axis, aberrations within the sub-beams can increase with radial displacement from the central axis. When secondary electrons are detected, these aberrations can remain associated with them. Therefore, these aberrations degrade the quality of the images produced during inspection.

[0041] The following describes the implementation of known multi-beam inspection devices.

[0042] The accompanying drawings are schematic. Therefore, for clarity, the relative dimensions of the components in the drawings are enlarged. In the following description of the drawings, the same or similar reference numerals refer to the same or similar components or entities, and only differences with respect to the various embodiments are described. Although the description and drawings are directed to an electro-optical device, it should be understood that these embodiments are not intended to limit this disclosure to specific charged particles. Therefore, references to electrons in this document can be more generally considered as references to charged particles, where charged particles are not necessarily electrons.

[0043] Now, for reference Figure 1 , Figure 1 This is a schematic diagram illustrating an exemplary charged particle beam inspection device 100. Figure 1 The charged particle beam inspection device 100 includes a main chamber 10, a load locking chamber 20, an electron beam tool 40, an equipment front-end module (EFEM) 30, and a controller 50. The electron beam tool 40 is located within the main chamber 10.

[0044] EFEM 30 includes a first loading port 30a and a second loading port 30b. EFEM 30 may include additional loading ports. For example, the first loading port 30a and the second loading port 30b may receive a front-opening wafer cassette (FOUP) containing a substrate (e.g., a semiconductor substrate or a substrate made of other materials) or a sample to be inspected (substrate, wafer, and sample are collectively referred to below as "sample"). One or more robotic arms (not shown) in EFEM 30 deliver the sample to the load-locking chamber 20.

[0045] A load-locked chamber 20 is used to remove gas surrounding the sample. This creates a vacuum with a local gas pressure lower than the surrounding environment pressure. The load-locked chamber 20 can be connected to a load-locked vacuum pump system (not shown) that removes gas particles from the load-locked chamber 20. Operation of the load-locked vacuum pump system allows the load-locked chamber to reach a first pressure below atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) transport the sample from the load-locked chamber 20 to the main chamber 10. The main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas particles from the main chamber 10, causing the pressure around the sample to reach a second pressure below the first pressure. After reaching the second pressure, the sample is transported to an electron beam tool 40 for examination. The electron beam tool 40 may include multi-beam electron optics.

[0046] The controller 50 is electrically connected to the electron beam tool 40. The controller 50 may be a processor (such as a computer) configured to control the charged particle beam inspection device 100. The controller 50 may also include a processing circuitry system configured to perform various signal and image processing functions. Although the controller 50 is... Figure 1 The controller 50 is shown as being located outside the structure comprising the main chamber 10, the load locking chamber 20, and the EFEM 30; however, it should be understood that the controller 50 may be part of this structure. The controller 50 may be located in one of the components of the charged particle beam inspection apparatus, or it may be distributed across at least two of the components. While this disclosure provides an example of a main chamber 10 for housing an electron beam inspection tool, it should be noted that aspects of this disclosure are not limited, in their broadest sense, to the chamber for housing an electron beam inspection tool. Rather, it should be understood that the above principles can also be applied to other arrangements of other tools and apparatuses operating under a second pressure.

[0047] Now, for reference Figure 2 , Figure 2 The diagram illustrates the inclusion of... Figure 1This is a schematic diagram of an exemplary electron beam tool 40, a part of an exemplary charged particle beam inspection apparatus 100. The multi-beam electron beam tool 40 (also referred to herein as apparatus 40) includes an electron source 201, a perforation plate 271, a condenser lens 210, a source conversion unit 220, a primary projection device 230, a motorized stage 209, and a sample holder 207. The electron source 201, perforation plate 271, condenser lens 210, and source conversion unit 220 are components of the irradiation apparatus included in the multi-beam electron beam tool 40. The sample holder 207 is supported by the motorized stage 209 to hold a sample 208 (e.g., a substrate or mask) for inspection. The multi-beam electron beam tool 40 may also include a secondary projection device 250 and associated electronic detection equipment 240. The primary projection device 230 may include an objective lens 231. The electronic detection equipment 240 may include a plurality of detection elements 241, 242, and 243. The beam splitter 233 and the deflection scanning unit 232 can be located inside the primary projection device 230.

[0048] The components used to generate the primary beam can be aligned with the primary electron optical axis of the device 40. These components may include an electron source 201, a bore plate 271, a condenser lens 210, a source conversion unit 220, a beam splitter 233, a deflection scanning unit 232, and a primary projection device 230. The secondary projection device 250 and its associated electronic detection equipment 240 can be aligned with the secondary electron optical axis 251 of the device 40.

[0049] The primary electron optical axis 204 is composed of the electron optical axis of the electron beam tool 40 as part of the irradiation device. The secondary electron optical axis 251 is the electron optical axis of the electron beam tool 40 as part of the detection device. The primary electron optical axis 204 may also be referred to herein as the primary optical axis (for ease of reference) or the charged particle optical axis. The secondary electron optical axis 251 may also be referred to herein as the secondary optical axis or the secondary charged particle optical axis.

[0050] The electron source 201 may include a cathode (not shown) and an extractor or anode (not shown). During operation, the electron source 201 is configured to emit electrons from the cathode as primary electrons. The primary electrons are extracted or accelerated by the extractor and / or the anode to form a primary electron beam 202, which forms a primary beam cross (virtual or real) 203. The primary electron beam 202 can be visualized as being emitted from the primary beam cross 203.

[0051] In this arrangement, the primary electron beam is a multi-beam upon its arrival at the sample, and preferably before its arrival at the projection device. This multi-beam can be generated from the primary electron beam in several different ways. For example, the multi-beam can be generated by a multi-beam array located before the intersection, a multi-beam array located in the source conversion unit 220, or a multi-beam array located at any point between these locations. The multi-beam array may include multiple electron beam manipulation elements arranged in an array across the beam path. Each manipulation element can influence the primary electron beam to generate a sub-beam. Thus, the multi-beam array interacts with the incident primary beam path to generate a multi-beam path below the beam of the multi-beam array.

[0052] During operation, the perforation plate 271 is configured to block peripheral electrons of the primary electron beam 202 to reduce the Coulomb effect. The Coulomb effect can enlarge the size of each of the detection points 221, 222, and 223 of the primary sub-beams 211, 212, and 213, thus reducing the inspection resolution. The perforation plate 271 may also be referred to as a Coulomb aperture array.

[0053] The condenser lens 210 is configured to focus (or substantially collimate) the primary electron beam 202. In one embodiment, the condenser lens 210 may be designed to focus (or substantially collimate) the primary electron beam 202 to become a substantially parallel beam and incident substantially perpendicularly onto the source conversion unit 220. The condenser lens 210 may be a movable condenser lens, which may be configured such that the position of its first principal plane is movable. In one embodiment, the movable condenser lens may be configured to physically move, for example, along the optical axis 204. Alternatively, the movable condenser lens may consist of two or more electro-optic elements (lenses), wherein the principal plane of the condenser lens moves with variations in the intensity of the respective electro-optic elements. The (movable) condenser lens may be configured as a magnetic lens, an electrostatic lens, or a combination of magnetic and electrostatic lenses. In another embodiment, the condenser lens 210 may be an anti-rotation condenser lens. When the focal length (collimation capability) of the condenser lens 210 changes and / or when the principal plane of the condenser lens moves, the anti-rotation condenser lens can be configured to maintain a constant rotation angle.

[0054] Source conversion unit 220 may include an image forming element array, an aberration compensator array, a beam limiting aperture array, and a pre-bent micro-deflector array. The pre-bent micro-deflector array can deflect multiple primary sub-beams 211, 212, 213 of the primary electron beam 202 to enter perpendicularly into the beam limiting aperture array, the image forming element array, and the aberration compensator array. In this arrangement, the image forming element array can function as a multi-beam array to generate multiple sub-beams, i.e., primary sub-beams 211, 212, 213, in a multi-beam path. The image forming array may include multiple electron beam manipulators, such as micro-deflectors, microlenses (or a combination of both), to influence the multiple primary sub-beams 211, 212, 213 of the primary electron beam 202 and form multiple parallel images (virtual or real images) of the primary beam cross 203, one parallel image for one of the primary sub-beams 211, 212, and 213. The aberration compensator array may include a field curvature compensator array (not shown) and an astigmatism compensator array (not shown). The field curvature compensator array may include multiple microlenses to compensate for field curvature aberrations of the primary sub-beams 211, 212, and 213. The astigmatism compensator array may include multiple micro-stigmators to compensate for astigmatic aberrations of the primary sub-beams 211, 212, and 213. The beam-limiting aperture array may be configured to limit the diameter of each primary sub-beam 211, 212, and 213. Figure 2 Three primary sub-beams 211, 212, and 213 are shown as examples, and it should be understood that the source conversion unit 220 can be configured to form any number of primary sub-beams. The controller 50 can be connected to... Figure 1 The charged particle beam inspection apparatus 100 includes various components such as the source conversion unit 220, electronic inspection equipment 240, primary projection device 230, or motorized stage 209. As explained in further detail below, the controller 50 can perform various image and signal processing functions. The controller 50 can also generate various control signals to manage the operation of the charged particle beam inspection apparatus, which includes a charged particle multi-beam device.

[0055] The condenser lens 210 can also be configured to adjust the current of the primary sub-beams 211, 212, and 213 below the beam of the source conversion unit 220 by changing the focal length of the condenser lens 210. Alternatively or additionally, the current of the primary sub-beams 211, 212, and 213 can be changed by altering the radial dimensions of the beam-limiting apertures corresponding to the respective primary sub-beams within the beam-limiting aperture array. If the condenser lens is a movable condenser lens and a magnetic condenser lens, the off-axis sub-beams 212 and 213 can be rotated to illuminate the source conversion unit 220. The rotation angle changes with the focal length of the movable condenser lens or the position of the first principal plane. The condenser lens 210, acting as an anti-rotation condenser lens, can be configured to maintain a constant rotation angle while changing the focal length of the condenser lens 210. This movable condenser lens 210 can maintain a constant rotation angle even when the focal length of the condenser lens 210 and the position of its first principal plane change.

[0056] Objective 231 can be configured to focus sub-beams 211, 212 and 213 onto sample 208 for inspection, and can form three detection points 221, 222 and 223 on the surface of sample 208.

[0057] The beam splitter 233 can be, for example, a Wien filter ( Figure 2 (Not shown in the image), it includes an electrostatic deflector that generates an electrostatic dipole field and a magnetic dipole field. In operation, the beam splitter 233 can be configured to apply electrostatic forces to the individual electrons of the primary sub-beams 211, 212, and 213 via the electrostatic dipole field. The electrostatic forces are equal in magnitude but opposite in direction to the magnetic force applied to the individual electrons by the magnetic dipole field of the beam splitter 233. Therefore, the primary sub-beams 211, 212, and 213 can pass through the beam splitter 233 at least substantially straight with at least substantially zero deflection angle.

[0058] In operation, the deflection scanning unit 232 is configured to deflect primary sub-beams 211, 212, and 213 to scan probe spots 221, 222, and 223 across segments of the surface of sample 208. In response to the primary sub-beams 211, 212, and 213 at incident or probe points 221, 222, and 223 on sample 208, electrons comprising secondary electrons and backscattered electrons are generated from sample 208. The secondary electrons propagate in three secondary electron beams 261, 262, and 263. The secondary electron beams 261, 262, and 263 typically contain secondary electrons (with electron energies ≤50 eV) and may also contain at least some backscattered electrons (with electron energies between 50 eV and the landing energies of the primary sub-beams 211, 212, and 213). Beam splitter 233 is arranged to deflect the paths of secondary electron beams 261, 262, and 263 toward secondary projection device 250. Secondary projection device 250 then focuses the paths of secondary electron beams 261, 262, and 263 onto multiple detection elements 241, 242, and 243 of electron detection device 240. Detection areas may be separate detection elements 241, 242, and 243 arranged to detect corresponding secondary electron beams 261, 262, and 263. Detection areas generate corresponding signals, which are sent to controller 50 or signal processing system (not shown), for example, to construct images of corresponding scan areas of sample 208.

[0059] Detection elements 241, 242, and 243 can detect corresponding secondary electron beams 261, 262, and 263. When the secondary electron beams are incident on detection elements 241, 242, and 243, these elements can generate corresponding intensity signal outputs (not shown). The outputs can be directed to an image processing system (e.g., controller 50). Each detection element 241, 242, and 243 can include one or more pixels. The intensity signal output of the detection element can be the sum of signals generated by all pixels within the detection element.

[0060] The controller 50 may include an image processing system comprising an image acquirer (not shown) and a storage device (not shown). For example, the controller may include a processor, computer, server, mainframe, terminal, personal computer, any type of mobile computing device, or a combination thereof. The image acquirer may include at least a portion of the controller's processing capabilities. Therefore, the image acquirer may include at least one or more processors. The image acquirer may be an electronic inspection device 240 communicatively coupled to the permitted signal communication device 40, such as an electrical conductor, fiber optic cable, portable storage medium, IR, Bluetooth, the Internet, wireless network, radio, or a combination thereof. The image acquirer may receive signals from the electronic inspection device 240, process data included in the signals, and construct an image from them. Therefore, the image acquirer may acquire an image of sample 208. The image acquirer may also perform various post-processing functions, such as generating contours, overlaying indicators on the acquired image, etc. The image acquirer may be configured to perform adjustments to the brightness and contrast of the acquired image, etc. The storage device may be a storage medium such as a hard disk, flash drive, cloud storage, random access memory (RAM), other types of computer-readable storage, etc. The storage device can be coupled to the image acquirer and can be used to save the scanned raw image data as both the raw image and the post-processed image.

[0061] The image acquirer can acquire one or more images of a sample based on imaging signals received from the electronic detection device 240. The imaging signals may correspond to a scanning operation used for imaging charged particles. The acquired image may be a single image comprising multiple imaging regions. The single image may be stored in a storage device. The single image may be an original image that can be divided into multiple regions. Each region within the multiple regions may include an imaging region containing features of the sample 208. The acquired images may include multiple images of a single imaging region of the sample 208 sampled multiple times within a time period. The multiple images may be stored in a storage device. The controller 50 may be configured to perform image processing steps using multiple images of the same location on the sample 208.

[0062] The controller 50 may include a measurement circuitry (e.g., an analog-to-digital converter) to obtain the distribution of the detected secondary electrons. The electron distribution data collected during the detection time window can be combined with corresponding scan path data from each of the primary sub-beams 211, 212, and 213 incident on the sample surface to reconstruct an image of the sample structure under inspection. The reconstructed image can be used to reveal various features of the internal or external structure of the sample 208. Therefore, the reconstructed image can be used to reveal any defects that may be present in the sample.

[0063] The controller 50 can control the motorized stage 209 to move the sample 208 during inspection. At least during sample inspection, the controller 50 can cause the motorized stage 209 to move the sample 208 in one direction (preferably continuously), for example, at a constant speed. The controller 50 can control the movement of the motorized stage 209 such that it changes the speed of movement of the sample 208 according to various parameters. For example, the controller can control the speed (including its direction) according to the characteristics of the inspection steps in the scanning process.

[0064] although Figure 2 The device 40 is shown to use three primary electron sub-beams; however, it should be understood that the device 40 may use two or more primary electron sub-beams. This disclosure does not limit the number of primary electron sub-beams used in the device 40.

[0065] Now, for reference Figure 3 , Figure 3 It's a diagram. Figure 1 This is a schematic diagram of an exemplary multi-beam device with an exemplary configuration of the source conversion unit of an exemplary charged particle beam inspection apparatus. The apparatus 300 may include an election source 301, a sub-beam pre-forming aperture array 372, and a focusing lens 310 (similar to...). Figure 2 Condensing lens 210), source conversion unit 320, objective lens 331 (similar to Figure 2 Objective 231) and sample 308 (similar to) Figure 2 (Sample 208). The election source 301, the sub-beam pre-forming aperture array 372, and the condenser lens 310 may be components of the irradiation device included in the device 300. The source conversion unit 320 and the objective lens 331 may be components of the projection device included in the device 300. The source conversion unit 320 may be similar to... Figure 2 The source conversion unit 220, wherein Figure 2 The image forming element array is an image forming element array 322. Figure 2 The aberration compensator array is an aberration compensator array 324. Figure 2 The beam limiting aperture array is beam limiting aperture array 321. Figure 2The pre-bent micro-deflector array is pre-bent micro-deflector array 323. The elector source 301, sub-beam preforming aperture array 372, condenser lens 310, source conversion unit 320, and objective lens 331 are aligned with the primary electron optical axis 304 of the device. The electron source 301 is typically along the primary electron optical axis 304 and generates a primary electron beam 302 using a (virtual or real) source crossover 301S. The sub-beam preforming aperture array 372 cuts the peripheral electrons of the primary electron beam 302 to reduce the resulting Coulomb effect. The Coulomb effect is a source of aberration in the sub-beam due to the interaction between electrons in different sub-beam paths. Through the sub-beam preforming aperture array 372 of the sub-beam preforming mechanism, the primary electron beam 302 can be trimmed into a specified number of sub-beams, such as three sub-beams 311, 312, and 313. Although three sub-beams and their paths are mentioned in the preceding and following descriptions, it should be understood that the description is intended to apply the apparatus, tool, or system to any number of sub-beams.

[0066] The source conversion unit 320 may include a beam-limiting aperture array 321 with beam-limiting apertures configured to limit sub-beams 311, 312, and 313 of the primary electron beam 302. The source conversion unit 320 may also include an image forming element array 322 with imaging micro-deflectors 322_1, 322_2, and 322_3. Each micro-deflector is associated with the path of each sub-beam. The micro-deflectors 322_1, 322_2, and 322_3 are configured to deflect the paths of the sub-beams 311, 312, and 313 toward the electron optical axis 304. The deflected sub-beams 311, 312, and 313 form a virtual image of the source crossover 301S. The virtual image is projected onto the sample 308 through an objective lens 331, and detection points are formed thereon, which are three detection points 391, 392, and 393. Each detector point corresponds to the incident position of the sub-beam path on the sample surface. The source conversion unit 320 may also include an aberration compensator array 324 configured to compensate for aberrations in each sub-beam. Aberrations in each sub-beam typically occur at detector points 391, 392, and 393 that may form on the sample surface. The aberration compensator array 324 may include microlenses and a field curvature compensator array (not shown). The field curvature compensator and microlenses are configured to compensate for sub-beams exhibiting significant field curvature aberrations in detector points 391, 392, and 393. The aberration compensator array 324 may include an astigmatism compensator array (not shown) with a micro-astigmatism ablation device. The micro-astigmatism ablation device is controlled to operate the sub-beams to compensate for astigmatism aberrations otherwise present in detector points 391, 392, and 393.

[0067] The source conversion unit 320 may further include a pre-bent micro-deflector array 323 having pre-bent micro-deflectors 323_1, 323_2, and 323_3 to bend sub-beams 311, 312, and 313, respectively. The pre-bent micro-deflectors 323_1, 323_2, and 323_3 can bend the paths of the sub-beams onto the beam confinement aperture array 321. The sub-beam paths incident on the beam confinement aperture array 321 can be orthogonal to the orientation plane of the beam confinement aperture array 321. A condenser lens 310 can guide the paths of the sub-beams onto the beam confinement aperture array 321. The condenser lens 310 can focus the three sub-beams 311, 312, and 313 into parallel beams along the primary electron optical axis 304, such that they are perpendicularly incident on the source conversion unit 320, which may correspond to the beam confinement aperture array 321.

[0068] The image forming element array 322, the aberration compensator array 324, and the pre-bending micro-deflector array 323 may include a multi-layer sub-beam manipulation device, some of which may be in the form of an array, such as a micro-deflector, microlens, or micro-astigmatism reducer.

[0069] In the source conversion unit 320, the sub-beams 311, 312, and 313 of the primary electron beam 302 are deflected toward the primary electron optical axis 304 by micro-deflectors 322_1, 322_2, and 322_3 of the image forming element array 322, respectively. It should be understood that the path of sub-beam 311 may already correspond to the electron optical axis 304 before reaching the micro-deflector 322_1, and therefore, the path of sub-beam 311 may not be deflected by the micro-deflector 322_1.

[0070] Objective lens 331 focuses the sub-beams onto the surface of sample 308, that is, it projects three virtual images onto the sample surface. The three images formed by the three sub-beams 311 to 313 on the sample surface form three detection points 391, 392, and 393 on the sample surface. The deflection angles of the sub-beams 311 to 313 are adjusted by objective lens 331 to reduce off-axis aberrations at the three detection points 391 to 393. Therefore, the three deflected sub-beams pass through or are close to the front focal point of objective lens 331.

[0071] Figure 2 and Figure 3 At least some of the aforementioned components may be referred to individually or in combination as a manipulator array or manipulator because they manipulate one or more beams or sub-beams of charged particles.

[0072] The multi-beam inspection tool described above includes a multi-beam charged particle optics device with a single charged particle source. The charged particle optics device includes an illumination device and a projection device. The illumination device can generate multi-beam charged particles from an electron beam from the source. The projection device projects multi-beam charged particles toward the sample lens. At least a portion of the sample surface is scanned using the multi-beam charged particles.

[0073] The problem with the multi-beam illumination apparatus described above is that the current of each of the multiple sub-beams is limited by the brightness of the source. The current of the sub-beam can depend on the ratio of the current supplied by the source to the uniform illumination area at the surface of the beam-limiting aperture array (which may be the upper surface of the source conversion unit 220). The electron sources used are typically high-brightness sources, such as Schottky sources or field emission sources. Some known sources of this kind are approaching the physical limits of achievable brightness. Therefore, improvements to the source design do not substantially increase their brightness. The physical limitations on the brightness of the electron source and the total emission current impose an inherent limitation on the number of sub-beams that can be generated by the source.

[0074] Another limitation on the number of sub-beams that can be provided is that increasing the number of sub-beams requires increasing the total area / field illuminated by the source, i.e., the illumination area of ​​the source. However, increasing the illumination area of ​​the source increases the aberrations of the condenser lens. In particular, the aberrations are greater for sub-beams that are at their maximum radial distance from the electronic optical axis of the illumination device.

[0075] Therefore, several problems exist, such as increasing the complexity of the number of beams provided by a multi-beam irradiation device with a single source.

[0076] A known method for increasing the number of beams in a multi-beam illumination device is to provide more than one source. Each source has its own column separate from the columns of the other sources. This method is roughly equivalent to providing multiple single-source illumination devices parallel to each other. One problem with this method is the spatial constraint on the components required for each column. In particular, due to the spatial constraint, the condenser lens for each column is required to be relatively small. However, reducing the size of the condenser lens increases the aberrations of the sub-beams.

[0077] Various embodiments improve upon the above-described technology by providing a scanning apparatus that includes an irradiation device having more than one source and only one column. The irradiation device can generate multi-beam charged particles. The irradiation device can be used in inspection apparatus, lithography apparatus, or for other applications.

[0078] Figure 4 A multi-source irradiation apparatus according to an embodiment is illustrated. In this embodiment, multiple sources are used to generate multiple beams of charged particles in a single-column configuration. Each sub-beam in the multiple beams may be a primary electron beam. The irradiation apparatus may be part of a single-column scanning device. The single-column scanning device may also include a single projection device.

[0079] The multi-source irradiation device includes multiple charged particle sources 401. Each source 401 can be compared with a previously referenced source. Figure 2 and Figure 3 The known charged particle sources 201 and 301 are described as being largely the same. Figure 4 The diagram shows three sources 401. However, embodiments include any number of sources 401, as long as the number of sources 401 is two or more. For example, the number of sources 401 can be 2, 3, 4, 5, 8, 9, 10, 16, 17, 25, 26, 34, or 35. These sources can be arranged in a grid; therefore, the number of sources can be 4, 9, 16, or any other real square.

[0080] The multi-source irradiation device includes a condenser lens 403. The condenser lens 403 has a plane through which the path of the charged particle beam from the source passes. The plane of the condenser lens 403 can be orthogonal to the charged particle optical axis of the irradiation device.

[0081] The multi-source irradiation device includes a manipulator system arranged as a manipulator array. The manipulator system may include at least two charged particle manipulator arrays 404 and 405, which may be a deflector array 404 and a manipulator array 405. Embodiments also include more than one manipulator system, with the deflector array 404 and manipulator array 405 provided separately from each other in different manipulator systems.

[0082] The deflector array 404 may include a plurality of separate deflectors, each having one or more deflector elements. The number of deflectors may be the same as the number of sources 401. There may be a one-to-one correspondence between each deflector and each source 401. Thus, each deflector may be arranged to deflect charged particles from a different source 401.

[0083] Manipulator array 405 may include one or more components for generating multiple beams based on each beam received by manipulator array 405. Thus, the multiple beams can be projected by a single-row charged particle projection device. Manipulator array 405 may include one or more components for manipulating one or more sub-beams of each multiple beam. For example, manipulator array 405 may include components for focusing sub-beams (such as a microlens array), components for deflecting sub-beams (such as a deflector array), components for changing the cross-sectional shape of sub-beams, and components for blanking sub-beams. Manipulator array 405 may include components related to... Figure 2 Source conversion unit 220 and / or primary projection device 230 and / or Figure 3The source conversion unit 320 contains components of essentially the same type. In one arrangement, the manipulator array 405 includes components that are essentially the same (if not completely identical) as those in the source conversion units 220, 320, or the primary projection device 230. Figure 2 Source conversion unit 220 and / or primary projection device 230 and / or Figure 3 Compared to the source conversion unit 320, the manipulator array 405 can support a substantially greater number of sub-beams.

[0084] The operation of the multi-source irradiation apparatus according to the embodiment will now be described. Each of the plurality of sources 401 generates and emits a beam of charged particles. The charged particles may be electrons. The beam generated by each source in the multi-source irradiation apparatus may be referred to herein as a 'source beam'.

[0085] The central axis of each charged particle source beam generated by source 401 can point to approximately the same position on the plane of condenser lens 403. Therefore, multiple source beams can intersect each other in the same region on the plane of condenser lens 403. That is, the central axes of multiple source beams intersect each other at the plane of condenser lens 403. The point of intersection of two or more source beams can be referred to as a cross-over. In a preferred implementation, all source beams intersect at the same cross-over. Further, the cross-over can be located at the center of the plane of the condenser lens that is approximately orthogonal to the charged particle optical axis of the irradiation device. Condenser lens 403 converts each source beam passing through it from a scattering beam path to a generally parallel or generally collimated beam path. Although embodiments include condenser lens 403 that converts each source beam path to a precisely collimated beam path, embodiments also include condenser lens 403 that converts each source beam path to a substantially collimated beam path. In other words, each source beam path may still diverge below the beam from the condenser lens. For example, the angle between the source beam path and the precisely collimated beam path could be ±10 mRad.

[0086] The intersection of the center point of the condenser lens 403 with the central axis of the source beams with different orientations allows the beam to increase the illumination area of ​​the manipulator system without significantly increasing the size of the condenser lens 403. Passing the beam through the center point or midpoint of the condenser lens 403 via the central axis of the source beams guided in different ways reduces aberrations in the generated beam. Increasing the illumination area allows for the provision of more sub-beams.

[0087] Multiple source beams from corresponding sources 401, having passed through condenser lens 403, each have a beam path that is approximately internally collimated (i.e., each beam is approximately collimated within its own beam path). The source beam paths from different sources diverge relative to each other. Deflector array 404 transforms these separate source beam paths into beam paths that are approximately parallel or approximately collimated to each other. The source beam paths below the beams from deflector array 404 can all be parallel to the charged particle optical axis of the irradiation device. The source beam from each source 401 can be deflected by a single deflector in deflector array 404. The beam paths below the beams from deflector array 404 are multiple separate source beams, each of which is generated by a different source 401. The spacing between the separate source beam paths can be very small in a direction orthogonal to the charged particle optical axis. This minimal spacing between the source beams below the deflector array 404 roughly produces a single beam referred to as a 'column beam' to distinguish it from the beam originating from a single source. This column beam can have a larger beam width than any of the source beams.

[0088] The deflector array 404 may include electrostatic deflectors and / or magnetic deflectors.

[0089] Below the beam of the deflector array 404, a column beam is input to the manipulator array 405. The manipulator array 405 can generate multiple sub-beams in a multi-beam manner based on the column beam received from the deflector array 404. The manipulator array 405 can also manipulate and adjust some or all of the sub-beams within the multi-beam array by, for example, focusing the sub-beams, deflecting the sub-beams, changing the cross-sectional shape of the sub-beams, and blanking the sub-beams.

[0090] The multi-beam path generated by the interaction between the beam array and the manipulator array 405 can be directed at the sample, such that the multi-beams illuminate a region on the sample according to known multi-beam projection techniques. The multi-beam path can be projected using a single-column projection device.

[0091] In another embodiment, the multi-source irradiation device further includes an aperture array 402, which may be referred to as a coulomb aperture array. The coulomb aperture array 402 (also referred to as a gun aperture array) is similar to... Figure 2 The gun aperture plate 271. The coulomb aperture array 402 receives source beams from at least one source 401. The coulomb aperture array 402 can receive source beams from all sources 401. The coulomb aperture array 402 can generate a source multi-beam based on each received source beam, that is, a multi-beam generated from a single source beam.

[0092] The operation of the condenser lens 403 is substantially the same as in the embodiment without the coulomb aperture array 402. The difference is that the condenser lens 403 receives source multi-beams instead of source beams from each source 401. The sub-beams in each source multi-beam above the beam of the condenser lens 403 can be divergent. Below the beam of the condenser lens 403, the multiple sub-beams in each source multi-beam can follow generally parallel or generally collimated paths. Thus, starting from the condenser lens, each source beam follows an internally collimated beam path. Each sub-beam within the multi-beam is collimated within the multi-beam path.

[0093] Below the beam of the focusing lens 403 is the deflector array 404. The deflector array 404 operates in the same way as described in the previous embodiments, except that each source beam is incident as a source multi-beam. Each source multi-beam received by a deflector in the deflector array 404 is deflected such that its source sub-beams are substantially parallel to the other source beam paths, or the source multi-beam path is below the beams from the other deflectors in the deflector array 404.

[0094] Below the beam of deflector array 404 is manipulator array 405. The operation of manipulator array 405 can be generally as described in the previous embodiments. Sub-beams incident on manipulator array 405 can be arranged such that, for each sub-beam, the illumination area of ​​the sub-beam on manipulator array 405 is larger than the aperture corresponding to the sub-beam on manipulator array 405. Therefore, the shape and current of each sub-beam below the beam from manipulator array 405 depend on the size and shape of the corresponding aperture of the sub-beam on manipulator array 405.

[0095] In the two embodiments described above, the components of the device can be implemented in several ways. Some implementations according to the embodiments are described below.

[0096] The manipulator array 405 and / or deflector array 404 may include at least one microelectromechanical system (MEMS). One or more MEMS may be provided for manipulating each sub-beam.

[0097] Manipulator array 405 and / or deflector array 404 can output shaped multi-beams. The shape of the manipulator array in the planar view (and therefore, the shape of the sub-beam array in the column beam) can be rectangular, square, rhomboid, or hexagonal. The multi-beam generated as sub-beams of the column multi-beam can be an N×N square array of sub-beams, where N is 3, 5, 6, 11, or 12. The number of sub-beams in the array can be between 100 and 5000.

[0098] The plane of the condenser lens 403 can be approximately perpendicular to the optical axis of the charged particles in the irradiation device. The multiple approximately parallel beams output from the deflector array 404 can be approximately parallel to the optical axis of the charged particles in the device.

[0099] All beams from all sources 401 may intersect each other in the same region in the plane of the condenser lens 403. Alternatively, two or more, but not all, beams from sources 401 may intersect each other in the same region in the plane of the condenser lens 403.

[0100] At the beam input to the manipulator array 405, the current density of the beam from each source 401 should be approximately the same, such that each sub-beam has approximately the same current. To this end, each source 401 can be arranged to have approximately the same emission current and approximately the same illumination area on the manipulator array 405. Variations in the emission current can be compensated for by variations in the illumination area, thereby maintaining a uniform current density at the aperture of the manipulator array 405.

[0101] Alternatively or additionally, each of the one or more sources 401 may include a controller for controlling the extraction voltage of that source. The emission current of the charged particle beam emitted by one or more sources 401 can be measured, and a feedback loop can control the extraction voltage. Therefore, the emission current of all sources 401 may be independently controllable and may also be controlled to be the same, or otherwise balanced and / or controlled in a suitable manner such that the current density from each source 401 is appropriate at the beam input to the manipulator array 405. The sources 401 may also all have the same or similar type and size.

[0102] Each of one or more sources 401 can emit a beam through an aperture structure having an opening. The aperture structure can be part of a source 401. The beam width of the beam emitted from a source 401 depends on the size and shape of the opening of the aperture structure and the emission opening angle of the source. One or more actuators can be provided to control the size and / or shape of the opening and / or the orientation of the aperture structure. The emission opening angle depends on the tip shape of the source 401 and the extraction field. Embodiments include controlling the emission opening angle by controlling the voltage at the anode of each source 410, thereby controlling the extraction field. Therefore, the beam width and orientation of the beam emitted by each of one or more sources 401 can be independently controllable.

[0103] Each aperture structure can be arranged to give the shape of the cross-section of the beam emitted by source 401. The aperture includes one or more openings. The basic shape of the one or more openings can be shaped as a rectangle, square, circle, linear slit, and / or curve, such as approximately crescent-shaped, for example, having a banana-shaped appearance.

[0104] At the input of the deflector array 404 and in a plane orthogonal to the charged particle optical axis of the device, the beam from each source 401 can be arranged such that it approaches the beam from another source 401, but does not overlap with the beam from the other source 401. This can be achieved through the proper positioning of the sources 401, the condenser lens 403, and the deflector array 404 relative to each other. Furthermore, this can be achieved through the techniques described above for controlling the beamwidth and beam direction of the beam emitted by the sources 401.

[0105] The condenser lens 403 can be a single lens. Alternatively, the condenser lens 403 can be a condenser lens arrangement 403 comprising multiple lenses arranged in series with each other. The multiple lenses can be arranged along the optical axis of the charged particles in the device. The beam from the source 401 passes through the multiple lenses of the condenser lens arrangement 403.

[0106] Two or more sources 401 can be arranged symmetrically about the charged particle optical axis of the device.

[0107] All sources 401 may be arranged in a plane orthogonal to the optical axis of the charged particles of the device. Alternatively, all sources 401 may be arranged equidistant from the midpoint of a region on the plane of the condenser lens 403 in which the beams from the sources 401 intersect each other.

[0108] The sources can be arranged such that when viewed along the optical axis of the charged particles, they appear as a circular or square grid. There may be four, nine, or sixteen sources, or in fact, the number of sources can be the square of a real number.

[0109] When the multi-source irradiation apparatus according to the embodiment is used to generate multiple beams, the spacing between adjacent sub-beams within the multiple beams can be approximately constant. That is, the pitch of the sub-beams in the multiple beams is substantially constant.

[0110] Figure 5 This is a flowchart illustrating the steps of a process for generating one or more charged particle beams for irradiating a sample, according to an embodiment.

[0111] In step 501, the process begins.

[0112] In step 503, charged particle beams are emitted from each of the plurality of sources such that the beams at least partially intersect.

[0113] In step 505, at locations where the beams along the optical axes of the charged particles at least partially intersect, the beams from each source are substantially collimated.

[0114] In step 507, the generally collimated beam is manipulated to generate one or more beams comprising charged particles from multiple sources in a single-row configuration.

[0115] In step 509, the process ends.

[0116] Optionally, between steps 503 and 505, the source beam can be converted into a multi-source beam by passing through the Coulomb aperture array 402. Therefore, at step 505, the multi-source beam is collimated such that the sub-beams within each multi-source beam are collimated within the multi-source beam path.

[0117] The embodiments also include many improvements to the above-described techniques.

[0118] Condensing lens structures can introduce aberrations in a beam. For a beam entering the condensing lens arrangement along an axis orthogonal to the plane of the condensing lens arrangement, the aberrations caused by the condensing lens arrangement are likely minimal. Aberrations can increase with increasing angle of the beam relative to the axis orthogonal to the plane of the condensing lens arrangement.

[0119] exist Figure 4 In the illustrated embodiment, the condenser lens arrangement 403 can cause aberrations in beams from sources not on the optical axis of charged particles. The aberrations caused by the condenser lens arrangement 403 can be reduced by decreasing the angle of entry of each beam into the condenser lens arrangement 403. The angle of entry of a beam is the angle between the beam path and an axis orthogonal to the plane of the condenser lens arrangement 403. The angle of entry of the beam can be reduced by positioning the sources 401 closer together. This might require increasing the distance between each source 401 and the condenser lens arrangement 403. However, due to space constraints within the device, it may be difficult to position the sources closer together. Increasing the distance between each source 401 and the condenser lens arrangement 403 may also be undesirable, as it may increase Coulomb interaction effects. Increasing the distance between each source 401 and the condenser lens arrangement 403 can also increase the aberrations reduced by decreasing the angle of entry. Therefore, increasing the distance between each source 401 and the condenser lens arrangement 403 can offset any gain gained by reducing the angle of entry.

[0120] Figure 6 An embodiment for reducing aberrations caused by the condenser lens arrangement 403 is shown. Note that the two elements for the condenser lens 403 are intended to indicate the possible effective or actual range of positions that the condenser lens 403 can have. This applies to other figures in which the condenser lens is present.

[0121] Figure 6 The illustrated apparatus includes a source 601 located on the optical axis of the charged particles, a source 602 not located on the optical axis of the charged particles, a source beam deflector 603, a focusing lens structure 403, and a manipulator array 404, 405. Each source 601, 602 can be coupled to the previously referenced... Figure 4The source 401 described is the same. The condenser lens arrangement 403 can be the same as condenser lens 403 or condenser lens arrangement 403, as previously referenced. Figure 4 As described. Manipulator arrays 404 and 405 can be referenced in the preceding text. Figure 4 The described manipulator arrays 404 and 405 are identical. Therefore, manipulator arrays 404 and 405 may include a manipulator array deflector 404 and a manipulator aperture array 405 for generating sub-beams.

[0122] Figure 6 The device shown is Figure 4 The illustrated device differs in that it also includes a source beam deflector 603 located in each beam path between the source 602 (not on the optical axis of the charged particles) and the condenser lens arrangement 403. The deflection of the beam from the source 602 above the beam in the condenser lens arrangement 403 reduces the angle of entry of the beam into the condenser lens arrangement 403. Advantageously, Figure 6 The implementation shown can reduce aberrations caused by the condenser lens arrangement 403. Sources 601 and 602 can be positioned further apart from each other, thus increasing the available space within the device for each source 601 and 602.

[0123] When the deflection angle applied by each source beam deflector 603 is the same, a single source ring 602 can be provided around the charged particle optical axis of the device. When the deflection angles applied by the source beam deflectors 603 differ, more than one source ring 602 can be provided around the charged particle optical axis. If the sources are located at different distances from the charged particle optical axis, the sources can be arranged on a grid, which can be, for example, a linear grid or a hexagonal grid.

[0124] As described above, manipulator arrays 404 and 405 may include a manipulator aperture array 405 for generating multiple beams based on each received beam. Embodiments also include techniques for varying the current of the sub-beams output from the manipulator aperture array 405.

[0125] In single-source multi-beam systems, it is known to use a condenser lens arrangement comprising two condenser lenses. By using more than one condenser lens, the manipulator aperture array can be illuminated by collimated beams when different beam currents are used. The beam current illuminating the manipulator aperture array depends on the illumination area of ​​the beam on the manipulator aperture array. The illumination area of ​​the beam on the manipulator aperture array can be varied by adjusting the condenser lens arrangement.

[0126] exist Figure 4 and Figure 6In the illustrated multi-source device, the condenser lens arrangement, including multiple lenses, can also be used to vary the beam current illuminating the manipulator aperture array 405. However, beams from different sources 601, 602 are preferably arranged / controlled such that they do not overlap on the manipulator aperture array 405. If a sub-beam aperture of the manipulator aperture array 405 is irradiated by source beams from more than one source 601, 602, the sub-beam generated by the sub-beam aperture can have a current substantially different from some of the other sub-beams. The Coulomb aperture effect can also be enhanced.

[0127] The embodiments include techniques that maintain a substantially constant illumination area of ​​the manipulator aperture array 405, implemented by each source beam, when the beam current of sources 601, 602 is changed. Therefore, the beam current can be changed, for example, by manipulating the condenser lens arrangement 403, without illuminating the sub-apertures of the manipulator aperture array with source beams from more than one source 601, 602. This allows control over the current of the sub-beams output from the manipulator aperture array 405.

[0128] Figure 7 and Figure 8 A technique for controlling the width of a source beam according to an embodiment is illustrated. For each source 601, 602, a corresponding width aperture 701, 801 can be provided. Each width aperture 701, 801 is arranged to constrain the width of the source beam, thereby constraining the maximum illumination area of ​​the manipulator aperture array 405 implemented by each source 601, 602. The width aperture may, for example, be an opening in a circular metal disk.

[0129] exist Figure 7 and Figure 8 In this diagram, only the width apertures 701 and 801 of the source 601 located on the charged particle optical axis are shown. However, the width apertures 701 and 801 can also be used in a similar manner for the source 602 located off-axis (i.e., not on the charged particle optical axis of the device). Note that the width apertures 701 and 801 are shown with solid and dashed outlines to indicate that these features can have a range of settings. The solid and dashed outlines of the beam path are intended to indicate the range of influence that the width apertures may have on the beam path.

[0130] exist Figure 7 In the illustrated embodiment, the diameter of the width aperture 701 may be constant. The degree to which the width aperture 701 constrains the width of the source beam can be varied by moving the width aperture 701 along the beam path of the source beam. That is, the position of the width aperture 701 on the path of the source beam can be variable and selectable.

[0131] exist Figure 8In the illustrated embodiment, the diameter of the width aperture 801 may be variable. The degree to which the width aperture 801 constrains the width of the source beam is varied by adjusting the size of the width aperture 801. For example, the diameter of a single width aperture 801 can be adjusted to adjust the beam width. Alternatively, a strip comprising multiple width apertures 801 may exist, each with a different diameter. The strip can be moved to change the width apertures 801 used. This allows for the selection of width apertures 801 of appropriate size.

[0132] The embodiments include width holes 701 and 801, such as Figure 7 Both can move along the beam path of the source beam, and as shown... Figure 8 The width holes 701 and 801 shown have adjustable dimensions.

[0133] Therefore, the embodiments include using width apertures to control the width of each source beam and using a focusing lens arrangement 403 to control the beam current illuminating the manipulator aperture array 405. Thus, for different beam currents, each source beam can have a substantially constant illumination area on the manipulator aperture array.

[0134] Figure 9A and Figure 9B Another embodiment for controlling the source beam current on the manipulator aperture array 405 is shown.

[0135] exist Figure 9A and Figure 9B In the embodiments shown, as referenced above Figure 6 As described, a source beam deflector 603 is used to reduce the angle of entry of each source beam into the condenser lens arrangement 403. The condenser lens arrangement 403 can be used to change the illumination area of ​​each beam on the manipulator aperture array 405.

[0136] Figure 9A A focusing lens arrangement 403 with a first configuration is shown, which is used to provide a minimum illumination area through each source beam, thereby providing a maximum sub-beam current.

[0137] Figure 9B A second configuration of condenser lens arrangement 403 is shown, which provides a larger illumination area through each source beam, thereby providing lower sub-beam current. Condenser lens arrangement 403 is used to generate a wider central beam, resulting in lower current per sub-beam aperture. This wider beam is used to cover more apertures in manipulator aperture array 405. Beams from other sources 602 are also wider. Source beam deflectors 603 are configured to deflect the input beams, thereby avoiding overlap between adjacent beams. Therefore, adjacent beams do not overlap each other.

[0138] Several known techniques can be used to control the condenser lens arrangement 403 to adjust the illumination area of ​​sources 601, 602. For example, the entire condenser lens arrangement 403 can be moved along the optical axis of the charged particles. Alternatively or additionally, the lenses within the condenser lens arrangement 403 can have variable parameters. For example, the lenses can move relative to each other. Alternatively or additionally, the condenser lens arrangement can include one or more electromagnetic lenses. The excitation state of each electromagnetic lens can differ, for example, due to different currents passing through the electromagnetic lens.

[0139] For each configuration of the condenser lens arrangement 403, the aperture angle of each source 601, 602 can be the same or vary.

[0140] like Figure 9B As shown, when each source beam is broadened, the collimated source beam does not fit within the manipulator array deflector 404. Although Figure 9B Not shown, but the embodiment includes moving the manipulator array deflector 404 and increasing the width between each pair of manipulator array deflectors 404. This allows the position of the manipulator array deflectors 404 to be changed so that each pair of manipulator array deflectors 404 can deflect a single beam in a suitable manner.

[0141] Alternatively, the manipulator array may not include, for example, Figure 9A The manipulator array deflector 404 shown is for each source beam. Alternatively, the manipulator array may include a separate deflector for each aperture in the manipulator aperture array 405. The deflector for each sub-beam may be located above or below each aperture in the manipulator aperture array 405.

[0142] Figure 10A and Figure 10B Another embodiment for controlling sub-beam current is shown. In this embodiment, the manipulator array includes a manipulator aperture array arrangement 1001. The manipulator aperture array arrangement 1001 includes two manipulator aperture arrays for defining the sub-beam. The first manipulator aperture array of the manipulator aperture array arrangement 1001 is arranged such that it is irradiated by the source beam and generates the sub-beam. These two manipulator arrays may be referred to as a first or up-beam manipulator aperture array and a second or down-beam manipulator aperture array 1002. The first manipulator array may be the same as the manipulator aperture array 405 in the above embodiment. The second manipulator aperture array of the manipulator aperture array arrangement 1001 is located below the beam of the first manipulator aperture array and is configured to receive the sub-beam generated by the first manipulator aperture array. The first and second manipulator aperture arrays may both be planar structures and in parallel planes. The first and second manipulator aperture arrays may be substantially identical to each other, wherein corresponding apertures in each array are aligned with each other in a direction parallel to the optical axis of the charged particle.

[0143] In this embodiment, the source beam width can be changed by manipulating the condenser lens arrangement 403, as previously referenced. Figure 9A and Figure 9B As described, the source beam deflector 603 can also be controlled to prevent the irradiation areas from adjacent source beams from overlapping on the surface of the first manipulator aperture array of the manipulator aperture array arrangement 1001.

[0144] In this embodiment, a pair of manipulator array deflectors 404 may be present for the beams from each source 601, 602. When the condenser lens arrangement 403 adopts the first configuration, such as Figure 10A As shown, the manipulator array deflectors 404 deflect the source beams so that they are orthogonal to the plane of the manipulator aperture array arrangement 1001. However, for the design of the manipulator aperture array arrangement 1001, functionally, it adopts... Figure 10A The device with the configuration shown is similar to the one using Figure 9A The apparatus shown is identical in configuration. The manipulator array arrangement 1001 is configured to be functionally identical to the manipulator aperture array 405. Beams from different sources can substantially cover the entire surface of the manipulator array deflector 404. The beams from different sources do not overlap.

[0145] When the condenser lens arrangement adopts the second configuration, such as Figure 10B As shown, the direction of each beam output from the manipulator array deflector 404 can depend on the source 601, 602 of the emitted beam. Each manipulator array deflector 404 can be associated with a source beam from one of the sources 601, 602. Each manipulator array deflector 404 can deflect the path of the associated source beam such that it is orthogonal to the plane of the manipulator aperture array arrangement 1001. The manipulator array deflector 404 can be positioned relative to the uplink beam array of the manipulator aperture array arrangement 1001 such that the beams from the source cover the uplink beam array. Each manipulator array deflector can be associated with a region of the uplink beam array and is arranged such that when the device is configured as... Figure 10A As shown, each beam is deflected in an appropriate manner. (See previous reference.) Figure 9A and Figure 9BAs described in the illustrated embodiment, each source beam can be wider. Therefore, each source beam can be wider than its associated deflector 404, and portions of the beam are either not deflected or deflected by deflectors other than the associated deflector 404. These undeflected and misdeflected portions of the beam may not have paths orthogonal to the uplink beam array 1001. Therefore, the first manipulator aperture array can generate sub-beams parallel to the charged particle optical axis and sub-beams not parallel to the charged particle optical axis. Due to the alignment of the apertures in the uplink and downlink beam manipulator aperture arrays 1001, sub-beams parallel to the charged particle optical axis pass through the downlink beam manipulator aperture array. That is, these sub-beams are not blocked by the second manipulator aperture array. However, sub-beams deviating from the angle parallel to the charged particle optical axis are blocked by the second manipulator aperture array. Therefore, all sub-beams output from the second manipulator aperture array can have the same current and resolution. Therefore, the use of the manipulator hole array arrangement 1001 allows for control of the sub-beam current, for example, by operating the condenser lens arrangement 403.

[0146] In all the above embodiments, depending on the circumstances, the deflection applied by all deflectors, such as the source beam deflector 603 and the manipulator array deflector 404, can be adjusted to align the source beam with the sub-beam aperture. The deflectors can be operated to achieve alignment for each configuration (e.g., setting) of the condenser lens arrangement 403.

[0147] Back Figure 6 In the embodiment shown, as described above, a source beam deflector 603 is disposed between a source 602 and a condenser lens arrangement 403 for each source 602 located away from the optical axis of the charged particles. The advantage of this is that it reduces the angle of entry of each beam into the condenser lens arrangement 403.

[0148] Deflecting a charged particle beam can increase its dispersion (i.e., chromatic aberration). The amount of dispersion caused by the deflector may depend on the deflection applied by the deflector, the energy spread of the beam at the deflector, and the beam energy at the deflector.

[0149] exist Figure 6 In the arrangement of source beam deflector 603 and manipulator array deflector 404 shown, the beams from each source 602, which are far from the optical axis of the charged particles, are deflected by two deflectors. Figure 6A potential problem with the specific arrangement shown is that the source beam deflector 603 and the manipulator array deflector 404 each apply a deflection component in the same direction. That is, each source beam deflector 603 applies a deflection that reduces the angle between the beam path and the charged particle's optical axis. Each manipulator array deflector 404 applies a further deflection that reduces the angle between the beam path and the charged particle's optical axis. The deflection angles applied by the two deflectors have the same sign (i.e., polarity). The result of applying deflections to all beam paths with the same polarity is that the dispersion effects caused by each of the applied deflections accumulate. In some applications, the total dispersion caused by all applied deflections may be unacceptable.

[0150] The embodiments also include techniques for reducing dispersion effects caused by applying deflection to the beam.

[0151] When there are two deflectors in the beam path, if the deflection angle applied by one deflector is opposite in sign to that applied by the other deflector, the dispersion caused by each deflector will at least partially cancel each other out. Furthermore, the total dispersion caused by the two deflectors can be minimized if the condition in equation [1] below is satisfied:

[0152] Equation 1

[0153] in

[0154] α d1 = The deflection angle applied to the beam path by the first deflector;

[0155] α d2 = The deflection angle applied to the same beam path by the second deflector;

[0156] L v.source@d1 = Optical distance between the first deflector and the virtual source of the beam;

[0157] L v.source@d2 =The optical distance between the second deflector and the virtual source of the beam;

[0158] U beam.energy@d1 = Beam energy at the first deflector; and

[0159] U beam.energy@d2 = Beam energy at the second deflector.

[0160] Each optical distance can be a distance along the beam path. The positions of each source 601, 602 can be considered as the positions of virtual sources. Each virtual source is the apparent position of a source of charged particle beams from a specific location on the beam path. The presence of optical components such as lenses and deflectors in the beam path can cause the positions of virtual sources to differ from the actual positions of the sources. Therefore, the position of each virtual source at a specific location on the beam path depends on all contributions to the imaging of charged particles above the beam at that specific location.

[0161] As long as the deflection angles applied by the deflectors in the beam path have opposite signs, the net dispersion caused by the deflectors will be lower than the individual dispersion caused by each deflector. In order to minimize the net dispersion and preferably reduce it to approximately zero, the magnitude of the applied deflection, the optical distance from each virtual source, and the beam energy can be configured to approximately satisfy the conditions in equation (1).

[0162] When more than two deflectors are present in the same beam path, net dispersion can also be minimized, and preferably reduced to approximately zero. The dispersion contribution from each deflector can be determined in a similar manner to that determined in Equation 1. Net dispersion caused by multiple deflectors is reduced as long as all deflection angles do not have the same sign. The magnitude of the applied deflection, the optical distance from each virtual source, and the beam energy can also be arranged to minimize net dispersion, and preferably to approximately zero.

[0163] Figure 11 It shows the improvement Figure 6 Three alternative source / deflector arrangements are shown as examples of the source / deflector arrangement. Figure 11 In this configuration, sources 602 not on the optical axis of the charged particles are arranged such that their beams are deflected by deflection angles with opposite signs. As explained above, this will at least partially reduce, and can be substantially eliminated, the dispersion effects caused by the source beam deflectors 603 and the manipulator array deflectors 404. In all implementations, the beam energy may be the same at each deflector. Alternatively, the beam energy can be controlled such that it differs at each deflector, so as to use the desired deflection angle in addition to achieving dispersion cancellation.

[0164] exist Figure 11 In the implementation shown in (a), one or more sources 602 that are not on the charged particle optical axis are positioned closer to the charged particle optical axis. A potential problem with this solution is that there may not be enough space within the device to accommodate sources 602 that are close to the charged particle optical axis.

[0165] I'm here too Figure 12 The one shown Figure 11In the implementation shown in (b), the source 602, located away from the charged particle optical axis, is positioned such that the beam path between each source 602 and its corresponding source beam deflector 603 intersects the charged particle optical axis. In this implementation, the difference in distance from the virtual source allows for a greater angular deflection applied by each source beam deflector 603 than by the manipulator array deflector 404. The beam path between position (b) and deflector 603 can intersect with the paths of different beams, thus carrying the risk of increased aberrations, such as those derived from Coulomb interactions.

[0166] I'm here too Figure 13 The one shown Figure 11 In the implementation shown in (c), the source 602, which is not on the optical axis of the charged particle, is positioned such that the angular deflection applied by each source beam deflector 603 is less than the angular deflection applied by the corresponding manipulator array deflector 404. The beam energy at the source beam deflector 603 can be less than the beam energy at the manipulator array deflector 404.

[0167] The embodiments also include other techniques for reducing aberrations in the beam from the source. Aberrations (e.g., dispersion) in the beam caused by the condenser lens arrangement depend on the radius of the footprint of the beam on the condenser lens arrangement. Therefore, aberrations can be reduced by decreasing the footprint of the beam, for example, by focusing the beam onto the condenser lens arrangement.

[0168] Figure 14 An embodiment in which a technique for reducing aberrations caused by the condenser lens arrangement 403 is applied is shown.

[0169] like Figure 14 As shown, a source aperture array 1401 is disposed between each source 601, 602 and a condenser lens arrangement 403. Each source aperture array 1401 generates multiple sub-beams based on the received beam and also focuses the sub-beams. Focusing can be performed by a microlens corresponding to each aperture. Therefore, each source aperture array 1401 may include multiple microlenses in a microlens array, which may also be referred to as a lens array. Each source aperture array 1401 may be a lens array as disclosed in US2004 / 0232349 A1, the entire contents of which are incorporated herein by reference.

[0170] Because the aberrations produced by focusing the sub-beams from each source 601, 602 onto the condenser lens arrangement 403 are reduced, the sources 601, 602 can be located further away from the condenser lens arrangement 403. This increases the available space within the device for accommodating the sources 601, 602.

[0171] The embodiments may also include reducing chromatic aberration by removing any unwanted portions of the beams emitted by each source 601, 602. For each source 601, 602, a corresponding macro-aperture may be provided below the beam of the condenser lens arrangement 403. Each macro-aperture may be configured such that desired multiple beams from sources 601, 602 can pass through it, but other beams from sources are substantially blocked.

[0172] In addition, aberrations can be reduced by increasing the beam energy. For example, aberrations can be reduced by increasing the beam energy from 30 kV to 200 kV.

[0173] Furthermore, aberrations can be reduced by using magnetic components instead of electrical components. For example, a magnetic deflector can be used instead of an electrical deflector.

[0174] Figure 15 Another embodiment in which a technique for reducing aberrations is applied is shown.

[0175] Figure 15 The illustrated embodiments and Figure 14 The embodiments shown are similar, wherein the source aperture array 1401 is disposed between each source 601, 602 and the condenser lens arrangement 403. Figure 15 The illustrated embodiments and Figure 14 The difference in the illustrated embodiment is that each source aperture array 1401 is configured to focus a sub-beam onto a manipulator array, rather than onto a condenser lens arrangement 403. For example, the sub-beam could be focused onto a manipulator array deflector 404.

[0176] By arranging the source aperture array 1401 to focus the sub-beams onto the manipulator array deflector 404, aberrations caused by the manipulator array deflector 404 are reduced. Aberrations caused by the manipulator array deflector 404 can be greater than those caused by the condenser lens arrangement 403; therefore, the overall aberration reduction may be more significant when the sub-beams are focused onto the manipulator array deflector 404.

[0177] Figure 16 Another embodiment is shown. Figure 16 The device includes source beam manipulators 1601 and 1602. Each source beam manipulator 1601 and 1602 is arranged between the source 601 and 602 and the condenser lens arrangement 403.

[0178] Each source beam manipulator 1602 targeting a source 602 offset from the optical axis of a charged particle includes a source beam deflector and a source aperture array. The source beam deflector may be similar to the source beam deflector 603 described above and is located above or below the beam of the source aperture array. If the source beam deflector 603 is located below the beam of the corresponding source aperture array, the source beam deflector may be in the form of a deflector array, with each deflector array serving one or a group of sub-beam paths. Each source aperture array may be similar to the previously referenced... Figure 14 and Figure 15 The source aperture array 1401 described is substantially the same. These source beam manipulators 1602 are arranged to both generate multiple beams based on the received beam and apply deflection such that the multiple beams have a different orientation from the beam received by the source beam manipulators 1602.

[0179] The source beam manipulator 1601 of the source 601 located on the optical axis of the charged particle may include a source aperture array, but does not include a source beam deflector. The source aperture array may be similar to that of the previously referenced source. Figure 14 and Figure 15 The source aperture array 1401 described is roughly the same.

[0180] All sources 601, 602 can be aligned in the same plane parallel to the plane of the condenser lens arrangement 403. Each source 601, 602 can be arranged to emit a beam in a direction parallel to or along the optical axis of the charged particles.

[0181] All source beam manipulators 1601 and 1602 can be aligned in the same plane parallel to the plane of the condenser lens arrangement 403. All source beam manipulators 1601 and 1602 can be configured as a single source beam manipulator arrangement.

[0182] Source beam manipulators 1601 and 1602 can focus the sub-beams onto the focusing lens arrangement 403 or the manipulator arrays 404 and 405, as previously referenced. Figure 14 and Figure 15 As described. Advantageously, this can reduce aberrations in the beam.

[0183] Another advantage of this embodiment is that the deflection applied by the source beam manipulators 1601 and 1602 is opposite in direction to the deflection applied by the manipulator array deflector 404. (See previous reference...) Figure 11 and Figure 13 As described, this can also reduce aberrations in the beam, especially dispersive effects.

[0184] Figure 17 Another embodiment excluding the source beam deflector is shown. Figure 17The apparatus includes source beam manipulators 1701. Each source beam manipulator 1701 is disposed between sources 601, 602 and a condenser lens arrangement 403. Each source beam manipulator 1701 includes a source aperture array. The source aperture array can be compared with a previously referenced... Figure 14 and Figure 15 The described source aperture arrays are roughly the same.

[0185] Source beam manipulator 1701 can focus the sub-beam onto the condenser lens arrangement 403 or the manipulator arrays 404, 405, as previously referenced. Figure 14 and Figure 15 As described. Advantageously, this can reduce aberrations in the beam.

[0186] This embodiment and Figure 16 The difference in the illustrated embodiment is that the source beam manipulator 1701 does not include a deflector. Therefore, the source 602, which is not on the optical axis of the charged particles, emits a beam that is directed towards the focusing lens arrangement 403.

[0187] Figure 17 The device in Figure 16 The similarities of the illustrated devices are that all sources 601 and 602 can be arranged in the same plane. All source beam manipulators 1701 can be arranged in the same plane. The plane including sources 601 and 602 and the plane including source beam manipulators 1701 can both be parallel to the plane of the condenser lens arrangement 403. All source beam manipulators 1701 can be configured as a single source beam manipulator arrangement.

[0188] As previously described, deflectors introduce aberrations in the beam they deflect. These aberrations can be reduced, and preferably substantially eliminated, by using more than one deflector in the beam path, wherein the at least one deflector is arranged such that the beam path includes a reverse deflection.

[0189] To further illustrate the condition in Equation 1 for reducing, and preferably approximately eliminating, the net aberration caused by the deflector, the optical distance (i.e., L) v.source@d1 and L v.source@d2 The optical distance is not limited to the optical distance from the virtual source. The optical distance used to roughly eliminate net aberration can be additionally or alternatively defined as the optical distance from each deflector to a common focal point or intermediate point. The common focal point or intermediate point may not be the virtual source, but rather the image of the virtual source. In particular, to calculate the total dispersion, the dispersion of various dispersive elements must be added. Dispersive elements include deflectors and lenses. Each optical distance can be between the dispersive element and the virtual source or between the dispersive element and the image of the virtual source.

[0190] Examples include, for example Figure 16 and Figure 17Variations of the illustrated embodiment. For each source not on the optical axis of the charged particle, a deflector set comprising multiple deflectors can be provided. The deflectors in each deflector set can be other deflectors along the beam path to the manipulator array deflector 404. The deflector set can, for example, include at least two deflectors. In a system with two deflectors, the deflectors can be located at:

[0191] a) All are above the beam of the source beam manipulator. One of the deflectors may be included in the source beam manipulator.

[0192] b) All are located below the beam of the source beam manipulator. One of the deflectors may be included in the source beam manipulator.

[0193] c) One is above the source beam manipulator and the other is below the source beam manipulator. One of the deflectors may be included in the source beam manipulator.

[0194] d) One is above the beam of the source beam manipulator, below the beam of the source beam manipulator, or included by the source beam manipulator, while the other is below the beam of the condenser lens.

[0195] In a system with three or more deflectors, the deflectors can be located at any of the positions described above for two sets of deflectors. Preferably, the net dispersion of all deflectors (along with other dispersive elements along the beam path) is zero or otherwise minimized.

[0196] Figure 18 It shows that Figure 16 The illustrated embodiment has been modified according to the technique described in a) above. That is, an additional deflector is located between each source 602 and the corresponding source beam manipulator 1602. Modifications can be made regarding... Figure 16 The arrangement shown is to achieve Figure 18 The arrangement allows the source to be located away from a common plane that can be orthogonal to the axes of charged particles. Alternatively, Figure 18 Can be considered Figure 17 Modifications have been made. These differences will be described later in this specification.

[0197] Figure 18 The illustrated embodiments may include Figure 16 All components of the illustrated embodiment. Sources 602 and 601 may be arranged in substantially the same plane. However, alternatively, deflector 603 may be used to allow sources 602 and 601 to be located away from the common plane. Figure 18 The source beam manipulators 1601 and 1602 shown can be used with Figure 16The source beam manipulators 1601 and 1602 shown are substantially the same. The deflector associated with the source beam manipulator 1602 can be located below or above the beam of the source beam manipulator 1602.

[0198] For each source 602 that deviates from the optical axis of the charged particle Figure 18 The illustrated embodiment may include a source beam deflector 603 between the source 602 and the source beam manipulator 1602. The source beam deflector 603 and the corresponding source beam manipulator 1602 apply opposite deflections to the same beam path, and this configuration can reduce aberrations, preferably minimize aberrations.

[0199] Regarding the application of conditions used to eliminate dispersion effects Figure 18 In the arrangement shown, the dispersive elements can be a source beam deflector 603, a condenser lens arrangement 403, and a source beam manipulator 1602. Although the device may also include a manipulator array deflector 404, its dispersive contribution can be avoided or ignored because the source beam manipulators 1601 and 1602 are arranged to focus the sub-beams onto the manipulator array deflector 404.

[0200] For each source beam deflector 603, the optical distance is the distance from the virtual source 602. For the condenser lens arrangement 403, the optical distance is the image of the virtual source. The image of the virtual source and the condenser lens arrangement 403 are in the same plane, so this distance is zero. For each source beam manipulator 1602, either the optical distance from the virtual source 602 or the optical distance from the image of the virtual source in the plane of the condenser lens arrangement 403 can be obtained.

[0201] The dispersion contributions of the accumulating virtual source to different images (i.e., intermediate images in the plane of virtual source 602 and condenser lens 403), which are in conjugate planes (i.e., they are images of each other) and have a magnification factor between them, can be transferred to the same virtual source or image by multiplying by the relevant magnification factor between these planes. It is irrelevant which virtual source or image the dispersion is transferred to, as long as all dispersion contributions with respect to the same image are calculated.

[0202] For example, for each source beam manipulator 1602, the optical distance can be the distance from the virtual source 602 or the distance from the intermediate image in the plane of the condenser lens arrangement 403. The magnification from the virtual source 602 to the intermediate image in the plane of the condenser lens arrangement 403 is given by the ratio of the optical distance from the virtual source 602 to the source beam manipulator 1602 to the optical distance from the source beam manipulator 1602 to the intermediate image in the plane of the condenser lens arrangement 403.

[0203] In this embodiment, at least one of sources 601 and 602 may not all be in the same plane. That is, at least one of sources 601 and 602 may be far from the common plane of some other sources.

[0204] Source beam manipulators 1601 and 1602 can be arranged to focus the sub-beam onto the condenser lens arrangement 403 or the manipulator array deflector 404. Figure 18 (not shown in the image). See previous reference. Figure 14 and Figure 15 As described, this can reduce aberrations. In particular, aberrations caused by this deflection can be significantly avoided by focusing the sub-beam onto the manipulator array deflector 404.

[0205] Figure 17 The embodiments shown can also be implemented using the techniques described above. Figure 18 The configuration. That is, adding a pair of deflectors [as in (a)], one deflector being above the beam of the source beam manipulator, and the other deflector being associated with the source beam manipulator 1602; for example, the deflector associated with the source beam manipulator can be above or below the beam or within the source beam manipulator 1602. If Figure 17 Source beam manipulator array for Figure 18 The arrangement of the deflector associated with the source beam manipulator 1602 is such that it can be located below the beam of the manipulator.

[0206] In modification Figure 17 In this embodiment, the apertures in the source aperture array of the source beam manipulator 1701 should be able to receive angled (i.e., non-orthogonal) beams from sources 602 that are not on the optical axis of the charged particles. This is in Figure 16 and Figure 18 The illustrated embodiment is also a necessary condition, for example, when the deflector included by the source beam manipulator 1602 is located above the beam of the source aperture array of the source beam manipulator 1602.

[0207] The apertures in the source aperture array that receive angled beams can be as follows:

[0208] -Small enough that the aberrations caused by the microlenses in each source beam manipulator are negligible, and / or

[0209] Each aperture can be configured to receive the same electron intensity, i.e., current. Therefore, the aperture size can increase with the distance between the aperture and the optical axis of the charged particle.

[0210] The apertures or openings in the source aperture array that receive angled beams can be shaped, such as elliptical. Elliptical openings can be shaped to have different radii with a maximum and a minimum radius. The maximum radius can be aligned with the direction of the beam path orthogonal to the source aperture array. The shape of the aperture can reduce aberrations caused by microlenses, making these aberrations negligible. Sub-beams generated by the apertures can also have similar shapes.

[0211] Figure 19 A plan view showing how the holes in the source hole array may be oriented.

[0212] exist Figure 19 In the illustrated embodiment, there are nine corresponding source aperture arrays. Each source aperture array can correspond to nine corresponding sources ( Figure 19 One of the sources (not shown). In this embodiment, the sources can be arranged in a square grid.

[0213] Source aperture array 1901 is located on the charged particle optical axis. All other source aperture arrays 1902 are located away from the charged particle axis.

[0214] like Figure 19 As shown, the holes in the source aperture array 1901 located on the charged particle optical axis may all be approximately circular. The holes in the source aperture array 1902, which is not on the charged particle optical axis, may be elliptical. The major axis of all elliptical holes may point towards the charged particle optical axis.

[0215] All aspects of the above embodiments can be applied together in the same apparatus. Specifically, although not shown in all the figures, the apparatus according to the embodiments may all include, Figure 4 and Figure 6 The manipulator arrays 404, 405, or as shown are... Figure 10B The manipulator array shown is arranged in 1001.

[0216] In the embodiments described above, source beam deflector 603, source aperture array 1401, and source beam manipulators 1601, 1602, and 1701 are all referenced. Each of these components may generally be referred to as a source beam manipulator arrangement.

[0217] In all embodiments described herein, each condenser lens 403 and / or condenser lens arrangement 403 may be configured to approximately or substantially collimate each received beam, and each received beam may not be fully collimated. Each condenser lens arrangement may be consistent with the above references. Figure 2 and Figure 3 The described focusing arrangement is the same as, or includes, components of, that focusing arrangement.

[0218] In all the above embodiments, adjustments applied to the condenser lens arrangement 403 (such as movement of the condenser lens arrangement 403 and / or movement of condenser lenses within the condenser lens arrangement 403) can result in beam rotation. This rotation may not require correction, especially if the rotation occurs before each beam is used to generate multiple beams. However, embodiments also include the application of known techniques to correct or avoid beam rotation of the condenser lens arrangement 403. For example, the techniques disclosed in EP3563400A1 can be applied.

[0219] The embodiments have been described with reference to charged particles. Charged particles can be electrons or other types of charged particles, such as protons.

[0220] Advantageously, the multi-source illumination apparatus according to the embodiment allows for the generation of multiple beams from multiple sources 401. Using multiple sources 401 allows for a relatively large illumination area at the input of the manipulator system. Because multiple sources 401 are used, the degree to which charged particles in the illumination area deviate from the axis of their source 401 is relatively small. Therefore, the aberrations are lower than when using a single source to provide the same illumination area.

[0221] Furthermore, using multiple sources 401 allows for an increase in total current compared to using a single source device. Therefore, the number of sub-beams available in a multi-beam configuration is less constrained compared to using a single source device.

[0222] A single-column arrangement is provided using a single condenser lens 403 or a single condenser lens arrangement 403 and a single manipulator system. This is superior to arrangements comprising multiple columns, which have greater problems due to space constraints, and in particular, problems due to increased aberrations caused by the use of smaller condenser lenses.

[0223] Because the scanning device according to the embodiment is a single-row projection device, it only needs to be small in size.

[0224] The multi-source irradiation apparatus according to the embodiments can be used in several different applications, which typically include electron microscopy, not just SEM and photolithography.

[0225] For example, embodiments include multi-beam inspection and / or measurement tools that include the multi-source irradiation apparatus described above according to embodiments. The multi-source irradiation apparatus may be part of a scanning device arranged to project multiple beams of charged particles onto a sample. The multi-beam inspection tool may include a detector arranged to detect charged particles, such as secondary electrons, received from the irradiated sample.

[0226] The embodiments also include a multi-beam lithography tool comprising a multi-source irradiation apparatus as described above according to the embodiments. The multi-source irradiation apparatus may be arranged to irradiate a resist on a substrate.

[0227] The embodiments include many modifications and variations of the above-described techniques.

[0228] In particular, the multi-source irradiation apparatus according to the embodiments may include the above-mentioned references. Figure 1 , Figure 2 and Figure 3 Any of the components of the described device.

[0229] Throughout this embodiment, a charged particle optical axis is described. This axis describes the path of the charged particles through and from the irradiation device. The sub-beams of the output multi-beam output can all be substantially parallel to the charged particle optical axis. The charged particle optical axis can be the same as or different from the mechanical axis of the irradiation device.

[0230] According to a first aspect of the invention, a multi-source irradiation apparatus for irradiating a sample with charged particles is provided, the apparatus comprising a plurality of sources, each arranged to emit a beam of charged particles; a condenser lens arranged to receive the beams from the plurality of sources; and a manipulator array arrangement configured to receive the beams that have passed through the condenser lens; wherein the beams are arranged such that, at the plane of the condenser lens, a beam from at least one source intersects at least a portion of another beam from a different source among the plurality of sources; the condenser lens is configured to separately and substantially collimate the beams received from each source; and the manipulator array arrangement is configured to manipulate the beams that have been substantially collimated by the condenser lens, thereby generating one or more beams comprising charged particles from the plurality of sources in a single column.

[0231] Preferably, the manipulator array arrangement includes a deflector array and a multi-beam generator, the deflector array being arranged to deflect a beam that has been substantially collimated by a focusing lens, thereby generating multiple substantially parallel and substantially collimated beams comprising charged particles from multiple sources.

[0232] Preferably, the manipulator array arrangement further includes a multi-beam generator, wherein the multi-beam generator is configured to: receive a plurality of generally parallel and generally collimated beams generated by the deflector array; and generate a multi-beam based on the received plurality of generally parallel and generally collimated beams, wherein the multi-beam includes a plurality of generally collimated sub-beams.

[0233] Preferably, the manipulator array arrangement is configured to manipulate at least one sub-beam.

[0234] Preferably, the manipulator array arrangement is configured to manipulate at least one sub-beam by applying one or more of the following to at least one sub-beam: focusing, deflection, change of cross-sectional shape, and blanking.

[0235] Preferably, the manipulator array arrangement includes at least one microelectromechanical system (MEMS).

[0236] Preferably, the multi-beam array is a rectangular, square, rhomboid, or hexagonal sub-beam array.

[0237] Preferably, the multi-beam array is an N×N approximately square sub-beam array; and N is 3, 5, 6, 11, 12 or 70.

[0238] Preferably, the method further includes a coulomb aperture array, wherein the coulomb aperture array is arranged in the path of the beam between the plurality of sources and the condenser lens; and the coulomb aperture array is arranged to receive a single beam from one or more of the sources, and for each received single beam, output a multi-beam based on the received single beam, wherein each output multi-beam of the coulomb aperture array comprises a plurality of charged particle sub-beams, such that the condenser lens receives and substantially collimates the one or more multi-beams, and a manipulator array is arranged to manipulate the one or more multi-beams.

[0239] Preferably, the plane of the condenser lens is approximately orthogonal to the optical axis of the charged particles in the device.

[0240] Preferably, the multiple generally parallel, collimated beams output from the deflector array are generally parallel to the optical axis of the charged particles in the device.

[0241] Preferably, the beam from each source intersects with the beam from each other source in the plane of the condenser lens.

[0242] Preferably, the beams from multiple sources intersect at the midpoint of the plane of the condenser lens.

[0243] Preferably, each of the one or more sources includes a controller for controlling the emission current of the charged particle beam emitted by the source.

[0244] Preferably, each of the one or more sources includes a controller for the emission aperture angle of the source.

[0245] Preferably, each source includes an aperture arranged to shape the beam emitted by the source; and the aperture includes one or more openings, the general shape of which is rectangular, square, circular, linear slit, banana-shaped, and / or curved.

[0246] Preferably, the condenser lens is composed of a condenser lens arrangement; the condenser lens arrangement includes multiple lenses, which are arranged in series such that one or more beams pass through the multiple lenses in the condenser lens arrangement.

[0247] Preferably, two or more sources are arranged symmetrically about the optical axis of the charged particles of the device.

[0248] Preferably, the number of sources is two, three, four, five, eight, nine, ten, sixteen, seventeen, twenty-five, twenty-six, thirty-four, or thirty-five.

[0249] Preferably, all sources are arranged in a plane that is approximately orthogonal to the optical axis of the charged particles of the device.

[0250] Preferably, these sources are arranged such that they are substantially equidistant from the midpoints of the regions where they intersect with the beams on the plane of the condenser lens.

[0251] Preferably, the manipulator array is arranged with a beam input, and the beams from each source are arranged such that at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, the irradiation area of ​​the beam is substantially adjacent to one or more other irradiation areas of the beams from other sources.

[0252] Preferably, at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, each irradiation area of ​​the beam does not substantially overlap with the irradiation area of ​​another beam.

[0253] Preferably, the charged particle is an electron.

[0254] According to a second aspect of the invention, a multi-beam inspection tool is provided, comprising a multi-source irradiation device according to the first aspect, wherein the multi-source irradiation device is arranged to irradiate a sample; and a detector arranged to detect charged particles received from the irradiated sample.

[0255] According to a third aspect of the invention, a multi-beam lithography tool is provided, comprising a multi-source irradiation device according to a first aspect, wherein the multi-source irradiation device is arranged to irradiate a resist on a substrate.

[0256] According to a fourth aspect of the invention, a multi-source irradiation apparatus for generating multiple beams of charged particles is provided, the apparatus comprising a plurality of sources, each arranged to emit a beam of charged particles; and a manipulator array arrangement including a beam input and a beam output; wherein the beam input is configured to receive beams from the plurality of sources; the beams are arranged such that at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, the irradiation area of ​​each beam is substantially adjacent to the irradiation area of ​​one or more other beams; and the manipulator array arrangement is configured such that multiple beams of charged particles are output from a single-column beam output.

[0257] Preferably, at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, each irradiation area does not substantially overlap with any other irradiation area.

[0258] Preferably, the beams are arranged such that the beams from all sources cross each other at one or more locations along the optical axis of the charged particles before reaching the beam input.

[0259] Preferably, the beams from all sources intersect each other in substantially the same region in a plane orthogonal to the optical axis of the charged particles.

[0260] Preferably, the method further includes a condenser lens disposed in a region of a plane in which the beams intersect each other; and optionally, the beams intersect each other at the midpoint of the condenser lens.

[0261] Preferably, the beam input is the input to the deflector array.

[0262] According to a fifth aspect of the invention, a method is provided for generating one or more charged particle beams for irradiating a sample, the method comprising: emitting charged particle beams through each of a plurality of sources such that the beams at least partially intersect; substantially collimating the beams from each source at a location where the beams at least partially intersect along the optical axes of the charged particles; and manipulating the substantially collimated beams to generate one or more beams comprising charged particles from the plurality of sources in a single column.

[0263] Preferably, the method further includes: generating multi-beam charged particles; and irradiating the sample with the multi-beams.

[0264] Preferably, the method is performed in the apparatus according to the first aspect.

[0265] According to a sixth aspect of the invention, a multi-source irradiation apparatus for irradiating a sample with charged particles is provided, the apparatus comprising a plurality of sources; a condenser lens arrangement configured to receive charged particle beams from each source and to collimate the beams from each source separately and substantially separately; at least one source beam manipulator arrangement, wherein each source beam manipulator arrangement is arranged between a source and the condenser lens arrangement and configured to operate on the beam therebetween; and a manipulator array arrangement configured to receive beams that have passed through the condenser lens arrangement and to generate a single multi-beam charged particle from the plurality of sources.

[0266] While the invention has been described in conjunction with various embodiments, other embodiments of the invention will be apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the appended claims.

[0267] 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 based on the description without departing from the scope of the claims set forth below.

[0268] The following clauses represent certain embodiments of the invention disclosed herein.

[0269] Clause 1: A multi-source irradiation apparatus for irradiating a sample with charged particles, the apparatus comprising a plurality of sources, each arranged to emit a beam of charged particles; a condenser lens arranged to receive the beams from the plurality of sources; and a manipulator array arrangement configured to receive the beams that have passed through the condenser lens; wherein the beams are arranged such that: at the plane of the condenser lens, a beam from at least one source intersects at least a portion of another beam from a different source among the plurality of sources; the condenser lens is configured to separately and substantially collimate the beams received from each source; and the manipulator array arrangement is configured to manipulate the beams that have been substantially collimated by the condenser lens to generate one or more beams comprising charged particles from the plurality of sources in a single column.

[0270] Clause 2: The apparatus according to Clause 1, wherein the manipulator array arrangement includes a deflector array and a multi-beam generator, the deflector array being arranged to deflect a beam that has been substantially collimated by a focusing lens, thereby generating a plurality of substantially parallel, substantially collimated beams comprising charged particles from a plurality of sources.

[0271] Clause 3: The apparatus according to Clause 2, wherein the manipulator array arrangement further includes a multi-beam generator, wherein the multi-beam generator is configured to:

[0272] Receives a plurality of generally parallel, generally collimated beams generated by a deflector array; and generates a multi-beam based on the received plurality of generally parallel, generally collimated beams, wherein the multi-beam includes a plurality of generally collimated sub-beams.

[0273] Clause 4: The apparatus according to any of the preceding clauses, wherein the manipulator array arrangement is configured to manipulate at least one of the sub-beams.

[0274] Clause 5: The apparatus according to Clause 4, wherein the manipulator array arrangement is configured to manipulate at least one sub-beam in the sub-beam by applying one or more of the following to at least one sub-beam: focusing, deflection, change of cross-sectional shape, and blanking.

[0275] Clause 6: The apparatus according to Clause 4 or 5, wherein the manipulator array arrangement includes at least one microelectromechanical system (MEMS).

[0276] Clause 7: The apparatus according to any one of Clauses 3 to 6, wherein the multiple beams are rectangular, square, rhomboid or hexagonal sub-beam arrays.

[0277] Clause 8: The apparatus according to Clause 7, wherein the multiple beams are an N×N generally square sub-beam array; and N is 3, 5, 6, 11, 12 or 70.

[0278] Clause 9: The apparatus according to any of the preceding clauses further includes a coulomb aperture array, wherein the coulomb aperture array is arranged in the path of the beam between the plurality of sources and the condenser lens; and the coulomb aperture array is arranged to receive a single beam from one or more of the sources, and for each received single beam, output multiple beams based on the received single beam, wherein each output multiple beam of the coulomb aperture array comprises a plurality of charged particle beams, such that the condenser lens receives and substantially collimates the one or more multiple beams, and a manipulator array is arranged to manipulate the one or more multiple beams.

[0279] Clause 10: In any of the preceding clauses, the plane of the condenser lens is substantially perpendicular to the optical axis of the charged particles of the device.

[0280] Clause 11: The apparatus according to any one of Clauses 2 to 10, wherein a plurality of generally parallel collimated beams output from the deflector array are generally parallel to the optical axis of the charged particles of the apparatus.

[0281] Clause 12: The apparatus according to any of the preceding clauses, wherein the beam from each source intersects with the beam from each other source in the plane of the condenser lens.

[0282] Clause 13: The apparatus according to any of the preceding clauses, wherein beams from a plurality of sources intersect at the midpoint in the plane of the condenser lens.

[0283] Clause 14: An apparatus according to any of the preceding clauses, wherein each of one or more sources includes a controller for controlling the emission current of a beam of charged particles emitted by the source.

[0284] Clause 15: The apparatus according to any of the preceding clauses, wherein each of one or more sources includes a controller for the emission aperture angle of the source.

[0285] Clause 16: The apparatus according to any of the preceding clauses, wherein each source includes an aperture arranged to shape a beam emitted by the source; and the aperture includes one or more openings generally in the shape of a rectangle, square, circle, linear slit, banana shape, and / or curve.

[0286] Clause 17: The apparatus according to any of the preceding clauses, wherein the condenser lens is constituted by a condenser lens arrangement; and the condenser lens arrangement includes a plurality of lenses arranged in series such that one or more beams pass through the plurality of lenses in the condenser lens arrangement.

[0287] Clause 18: A device according to any of the preceding clauses, wherein two or more sources are arranged symmetrically about the charged particle optical axis of the device.

[0288] Clause 19: The number of sources in any of the preceding clauses is two, three, four, five, eight, nine, ten, sixteen, seventeen, twenty-five, twenty-six, thirty-four, or thirty-five.

[0289] Clause 20: A device according to any of the preceding clauses, wherein all sources are arranged in a plane substantially perpendicular to the optical axis of the charged particles of the device.

[0290] Clause 21: An apparatus according to any one of Clauses 1 to 19, wherein the sources are arranged such that the midpoints of the regions intersecting the beams on the plane of the condenser lens are substantially equidistant.

[0291] Clause 22: A device according to any of the preceding clauses, wherein the manipulator array is arranged to have a beam input, and the beams from each source are arranged such that at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, the irradiation area of ​​the beam is substantially adjacent to one or more other irradiation areas of the beams from the other sources.

[0292] Clause 23: The apparatus according to Clause 22, wherein at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, each irradiated area of ​​the beam does not substantially overlap with the irradiated area of ​​another beam.

[0293] Clause 24: A device according to any of the preceding clauses, wherein the charged particle is an electron.

[0294] Clause 25: A multi-source irradiation apparatus for generating multiple beams of charged particles, the apparatus comprising a plurality of sources, each arranged to emit a beam of charged particles; and a manipulator array arrangement including a beam input and a beam output; wherein the beam input is configured to receive beams from the plurality of sources; the beams are arranged such that at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, the irradiation area of ​​each beam is substantially adjacent to the irradiation area of ​​one or more other beams; and the manipulator array arrangement is configured to output multiple beams of charged particles from a single row of beam outputs.

[0295] Clause 26: The apparatus according to Clause 25, wherein at the beam input and in a plane substantially orthogonal to the optical axis of the charged particles, each irradiation region does not substantially overlap with any other irradiation region.

[0296] Clause 27: The apparatus according to Clause 25 or 26, wherein the beams are arranged such that the beams from all sources cross each other at one or more locations along the optical axis of the charged particles before reaching the beam input.

[0297] Clause 28: The apparatus according to Clause 27, wherein beams from all sources intersect each other in substantially the same region in a plane orthogonal to the optical axis of the charged particles.

[0298] Clause 29: The apparatus according to Clause 28 further includes a condensing lens disposed in a region in a plane in which the beams intersect each other; and optionally, the beams intersect each other at the midpoint of the condensing lens.

[0299] Clause 30: The apparatus according to any one of Clauses 25 to 29, wherein the beam input is the input to the deflector array.

[0300] Clause 31: A multi-beam inspection and / or measurement tool, comprising:

[0301] A multi-source irradiation device according to any of the foregoing clauses, wherein the multi-source irradiation device is arranged to irradiate a sample; and

[0302] The detector is arranged to detect charged particles received from the irradiated sample.

[0303] Clause 32: A multi-beam lithography tool comprising a multi-source irradiation device according to any one of Clauses 1 to 30, wherein the multi-source irradiation device is arranged to irradiate a resist on a substrate.

[0304] Clause 33: A method for generating one or more beams of charged particles for irradiating a sample, the method comprising: emitting the beams of charged particles through each of a plurality of sources such that the beams at least partially intersect; substantially collimating the beams from each source at a location where the beams at least partially intersect along the optical axes of the charged particles; manipulating the substantially collimated beams to generate one or more beams comprising charged particles from the plurality of sources in a single column.

[0305] Clause 34: The method according to Clause 33, wherein the method further comprises: generating multi-beam charged particles; and irradiating a sample with the multi-beams.

[0306] Clause 35: The method according to Clause 33 or 34, wherein the method is performed in the apparatus according to any one of Clauses 1 to 30.

[0307] The following other clauses also represent certain embodiments of the invention disclosed herein.

[0308] Other Clause 1: A multi-source irradiation apparatus for irradiating a sample with charged particles, the apparatus comprising a plurality of sources; a condenser lens arrangement configured to receive charged particle beams from each source and to collimate the beams from each source separately and substantially separately; at least one source beam manipulator arrangement, wherein each source beam manipulator arrangement is arranged between a source and a condenser lens arrangement and configured to operate on the beam therebetween; and a manipulator array arrangement configured to receive beams that have passed through the condenser lens arrangement and to generate a single multi-beam charged particle from the plurality of sources.

[0309] Other Clause 2: The apparatus according to Other Clause 1, wherein the manipulator array arrangement is configured to deflect the beam paths of one or more of a plurality of sources.

[0310] Other Clause 3: The apparatus according to Other Clause 1 or 2, wherein the arrangement of the manipulator array is generally planar; and the optical axis of the charged particles of the apparatus is an axis that is generally orthogonal to the plane of the manipulator array arrangement.

[0311] Other Clause 4: The apparatus according to any of the preceding other clauses, wherein the path of the beam emitted from at least one of the sources is generally parallel to or generally parallel to the optical axis of the charged particles.

[0312] Other Clause 5: The apparatus according to any of the preceding other clauses, wherein each source beam manipulator arrangement includes a deflector for deflecting the beam path.

[0313] Other Clause 6: The apparatus according to Other Clause 5, wherein each source beam manipulator arrangement is configured to deflect a beam path by a first deflection angle; and the manipulator array arrangement is configured to deflect each beam path that has been deflected by the source beam manipulator arrangement by a second deflection angle.

[0314] Other Clause 7: The apparatus according to Other Clause 6, wherein for each beam path including a first deflection angle and a second deflection angle, each first deflection angle has a sign opposite to that of the second deflection angle.

[0315] Other Clause 8: The apparatus according to Other Clause 6 or 7, wherein for each beam path including a first deflection angle and a second deflection angle, the first deflection angle includes a deflection component orthogonal to the charged particle optical axis; and the second deflection angle includes a deflection component orthogonal to the charged particle optical axis and directed in the opposite direction to the first deflection angle.

[0316] Other Clause 9: The apparatus according to any one of Other Clauses 5 to 8, wherein for each source beam manipulator arrangement, the source beam manipulator arrangement and the manipulator array arrangement are configured such that:

[0317]

[0318] in

[0319] α d1 =The deflection angle applied to the beam path by the source beam manipulator arrangement;

[0320] α d2 = The deflection angle applied to the same beam path by the arrangement of the manipulator array;

[0321] L v.source@d1 =The optical distance between the source beam manipulator arrangement and the virtual source of the beam, the image of the virtual source, the common focus and / or the midpoint;

[0322] L v.source@d2 =Optical distance between the manipulator array arrangement and the virtual source of the beam, the image of the virtual source, the common focus and / or the intermediate point;

[0323] U beam.energy@d1 =The beam energy at the location of the source beam manipulator; and

[0324] U beam.energy@d2 = Beam energy at the location of the manipulator array.

[0325] Other Clause 10: The apparatus according to any one of Other Clauses 5 to 9, wherein for each source beam manipulator arrangement, the source beam manipulator arrangement and the manipulator array arrangement are configured such that the overall aberration is reduced by a combination of the following: the deflection angle applied to the beam path by the source beam manipulator arrangement; the deflection angle applied to the same beam path by the manipulator array arrangement; the optical distance between the source beam manipulator arrangement and the virtual source of the beam, the image of the virtual source, the common focus and / or the intermediate point; the optical distance between the manipulator array arrangement and the virtual source of the beam, the image of the virtual source, the common focus and / or the intermediate point; the beam energy at the source beam manipulator arrangement; and the beam energy at the manipulator array arrangement.

[0326] Other Clause 11: The apparatus according to any one of Other Clauses 5 to 10, wherein two or more dispersive elements in at least one beam path of the beam path are arranged such that the dispersive effects of the two or more dispersive elements at least partially cancel each other out.

[0327] Other Clause 12: The apparatus according to any one of Other Clauses 5 to 11, wherein each source beam manipulator arrangement is configured to guide the beam path across the charged particle optical axis of the apparatus before the beam reaches the condenser lens arrangement.

[0328] Other Clause 13: The apparatus according to any one of Other Clauses 5 to 12, wherein each source beam manipulator arrangement is configured to guide the beam path such that the beam path first intersects with the beam paths of one or more other sources in the condenser lens arrangement.

[0329] Other Clause 14: The apparatus according to any of the preceding other clauses, wherein the path of the beam emitted from the source is generally along or generally parallel to the optical axis of the charged particles; and the condenser lens arrangement is configured to receive the beam from the source without the beam being manipulated by the source beam manipulator arrangement.

[0330] Other Clause 15: The apparatus according to any one of Other Clauses 1 to 13, wherein the source beam manipulator arrangement is disposed between each source and the condenser lens arrangement.

[0331] Other Clause 16: The apparatus according to Other Clause 15, wherein each source beam manipulator arrangement includes a multi-beam generator configured to generate a plurality of sub-beams based on the received source beam.

[0332] Other Clause 17: The apparatus according to Other Clause 16, wherein each source beam manipulator arrangement includes a microlens array configured to focus each sub-beam.

[0333] Other Clause 18: The apparatus according to Other Clause 17, wherein each microlens array is configured to focus the sub-beams substantially onto the condenser lens arrangement.

[0334] Other Clause 19: The apparatus according to Other Clause 17, wherein each microlens array is configured to focus the sub-beams substantially onto the manipulator array arrangement.

[0335] Other Clause 20: The apparatus according to any one of Other Clauses 15 to 19, wherein all of the source beam manipulator arrangements are arranged in the same plane; and optionally, the source beam manipulator arrangements are arranged in a plane parallel to the plane of the condenser lens arrangement.

[0336] Other Clause 21: The apparatus according to any one of Other Clauses 15 to 20, wherein one or more source beam manipulator arrangements include a multi-beam generator, a microlens array, and a deflector.

[0337] Other Clause 22: The apparatus according to any one of Other Clauses 15 to 21, wherein all such sources are arranged in the same plane; and optionally, the sources are arranged in a plane parallel to the plane of the condenser lens arrangement.

[0338] Other Clause 23: The apparatus according to any one of Other Clauses 15 to 22, wherein all source beam manipulator arrangements constitute a multi-source beam manipulator arrangement.

[0339] Other Clause 24: The apparatus according to any one of Other Clauses 15 to 23, wherein for each source, the beam path of the beam emitted from the source is orthogonal to the source beam manipulator arrangement configured to manipulate the beam.

[0340] Other Clause 25: The apparatus according to any one of Other Clauses 15 to 24, wherein one or more source beam manipulator arrangements in the source beam manipulator arrangement include an elliptical aperture.

[0341] Other Clause 26: In the apparatus according to any one of Other Clauses 15 to 25, for each of the one or more sources, the apparatus further includes a set of deflectors configured to deflect a beam emitted from the source; wherein each set of deflectors includes a plurality of deflectors; and the set of deflectors includes a first deflector and a second deflector configured to apply deflections having opposite signs.

[0342] Other Clause 27: The apparatus according to Other Clause 26, wherein the first deflector and the second deflector are arranged such that: both the first deflector and the second deflector are above the beam of the source beam manipulator arrangement; both the first deflector and the second deflector are below the beam of the source beam manipulator arrangement; the first deflector is above the beam of the source beam manipulator arrangement and the second deflector is below the beam of the source beam manipulator arrangement; the first deflector is composed of the source beam manipulator arrangement and the second deflector is below the beam of the source beam manipulator arrangement; or the second deflector is composed of the source beam manipulator arrangement and the first deflector is above the beam of the source beam manipulator arrangement.

[0343] Other Clause 28: The apparatus according to any of the preceding other clauses, wherein the condenser lens arrangement is movable along at least one of the beam paths, along the optical axis of the charged particles, and / or movable in a proximity manner relative to the manipulator array arrangement.

[0344] Other Clause 29: The apparatus according to any of the preceding other clauses, wherein the condenser lens arrangement is configured such that the beam width of each beam output from the condenser lens arrangement is adjustable.

[0345] Other Clause 30: The apparatus according to any of the preceding other clauses, wherein the condenser lens arrangement includes an electromagnetic lens; and the excitation level of the lens is variable.

[0346] Other Clause 31: The apparatus according to Other Clause 27 or 28, wherein the condenser lens arrangement includes a plurality of condenser lenses, each of which is configured to have variable parameters such that the characteristics of the condenser lens arrangement are adjustable.

[0347] Other Clause 32: The apparatus according to Other Clause 31, wherein the variable parameter is the displacement between a plurality of condenser lenses such that they can move relative to each other.

[0348] Other Clause 33: The apparatus according to any of the preceding other clauses further includes one or more width apertures, wherein each width aperture is configured to adjust the width of the beam from the source.

[0349] Other Clause 34: The apparatus according to Other Clause 33, wherein each width aperture is configured to be operable by movement along the beam path in order to adjust the width of the beam.

[0350] Other Clause 35: The apparatus according to Other Clause 33 or 34, wherein each width aperture is configured to be operable by having an adjustable aperture size (preferably, the diameter of the aperture) in order to adjust the width of the beam.

[0351] Other Clause 36: The apparatus according to any of the preceding other clauses, wherein the manipulator array arrangement includes a first aperture array for generating a plurality of sub-beams in a single column; and a second aperture array having a aperture arrangement substantially the same as that of the first aperture array; wherein the second aperture array is located below the beams of the first aperture array and is arranged such that, in use, each aperture of the second aperture array receives a sub-beam from a corresponding aperture of the first aperture array.

Claims

1. A multi-source illumination apparatus for illuminating a sample using charged particle illumination, the apparatus comprising: a plurality of sources each arranged to emit a beam of charged particles; a condenser lens arranged to receive beams from the plurality of sources; and a manipulator array arrangement configured to receive beams that have passed through the condenser lens; wherein the beams are arranged such that, at a plane of the condenser lens, a beam from at least one source intersects at least a portion of another beam from a different one of the plurality of sources; the condenser lens is configured to collimate separately beams received from each source; and the manipulator array arrangement is configured to manipulate beams that have been collimated by the condenser lens to generate one or more beams comprising charged particles from the plurality of sources in the form of a single column, the manipulator array arrangement comprising a deflector array and a multi-beam generator, the deflector array being arranged to deflect the beams that have been collimated by the condenser lens to generate a plurality of parallel collimated beams comprising charged particles from the plurality of sources, wherein the multi-beam generator is configured to: receive the plurality of parallel collimated beams generated by the deflector array; and generate, in dependence on each of the received plurality of parallel collimated beams, a multi-beam of sub-beams, wherein the multi-beam comprises a plurality of collimated sub-beams.

2. The apparatus of claim 1, wherein the manipulator array arrangement is configured to manipulate at least one of the sub-beams.

3. The apparatus of claim 1 or 2, wherein the multi-beam is an array of rectangular, square, diamond or hexagonal shaped sub-beams.

4. The apparatus of claim 1 or 2, further comprising a Coulombic aperture array, wherein the Coulombic aperture array is arranged in a path of the beams between the plurality of sources and the condenser lens; and the Coulombic aperture array is arranged to receive a single beam from one or more of the sources and, for each received single beam, to output a multi-beam in dependence on the received single beam, wherein each outputted multi-beam of the Coulombic aperture array comprises a plurality of charged particle sub-beams, such that the condenser lens receives and collimates one or more multi-beams and the manipulator array arrangement manipulates one or more multi-beams.

5. The apparatus of claim 1 or 2, wherein the plurality of parallel collimated beams outputted from the deflector array are parallel to a charged particle optical axis of the apparatus.

6. The apparatus of claim 1 or 2, wherein a beam from each source intersects a beam from each of the other sources in the plane of the condenser lens.

7. The apparatus of claim 1 or 2, wherein beams from a plurality of sources intersect at a midpoint in the plane of the condenser lens.

8. The apparatus of claim 1 or 2, wherein each of one or more of the sources comprises a controller for controlling an emission current of the beam of charged particles emitted by the source. ​ ​ 9. The apparatus of claim 1 or 2, wherein each of one or more of the sources comprises a controller of the source’s emission opening angle.

10. The apparatus of claim 1 or 2, wherein two or more of the sources are arranged symmetrically about a charged-particle optical axis of the apparatus.

11. The apparatus of claim 1 or 2, wherein all of the sources are arranged in a plane orthogonal to a charged-particle optical axis of the apparatus.

12. The apparatus of claim 1 or 2, wherein the manipulator array arrangement has a beam input, and the beams from each source are arranged such that, at the beam input and in a plane orthogonal to a charged-particle optical axis of the apparatus, an illumination area of the beam abuts one or more other illumination areas of beams from other sources.

13. The apparatus of claim 2, wherein the manipulator array arrangement is configured to manipulate at least one of the sub-beams by applying one or more of the following to the at least one of the sub-beams: focusing, deflection, change of cross-sectional shape, and blanking.

14. The apparatus of claim 6, wherein the condenser lens comprises a magnetic lens.

15. A multi-beam inspection and / or metrology tool, comprising: a multi-source illumination apparatus according to any of claims 1 to 14, wherein the multi-source illumination apparatus is arranged to illuminate a sample; and a detector arranged to detect charged particles received from the illuminated sample.

16. A multi-beam lithography tool, comprising a multi-source illumination apparatus according to any of claims 1 to 14, wherein the multi-source illumination apparatus is arranged to illuminate resist on a substrate.

17. A method of generating one or more charged-particle beams for illuminating a sample, the method comprising: emitting a charged-particle beam by each of a plurality of sources such that the beams at least partially intersect; at a location along a charged-particle optical axis at which the beams at least partially intersect, collimating the beam from each source; manipulating the collimated beams, thereby generating one or more beams comprising charged particles from the plurality of sources in a single column, the manipulating comprising: - deflecting the collimated beams, thereby generating a plurality of parallel collimated beams comprising charged particles from the plurality of sources, and - receiving the plurality of parallel collimated beams, and then generating a multi-beam of sub-beams in dependence on each of the received plurality of parallel collimated beams, wherein the multi-beam comprises a plurality of collimated sub-beams.

Images