Stacking alignment technique

Abstract

Disclosed herein is a substrate stack comprising a plurality of substrates, wherein: each substrate in the substrate stack comprises at least one set of alignment openings; the at least one set of alignment openings in each substrate is aligned for passing a light beam through corresponding alignment openings in each substrate; and each substrate comprises at least one alignment opening having a smaller diameter than corresponding alignment openings in other substrates.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to EP application 20165332.6, filed on March 24, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] The embodiments provided herein generally relate to techniques that can be used to determine the alignment of substrates in a substrate stack. The embodiments are particularly applicable to the manufacture and / or testing of devices for manipulating sub-beams of charged particles in a multi-beam charged particle device. 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, as a result of optical effects and incident particles, thereby reducing yield. Therefore, monitoring the extent of these 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 introductory processes during and / or after manufacturing.

[0005] Pattern inspection tools with charged particle beams have been used to inspect objects (e.g., to detect pattern defects). These tools typically employ electron microscopy techniques, such as scanning electron microscopy (SEM). In SEM, a primary electron beam with relatively high-energy electrons targets a final deceleration step to land on the sample at 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, over the sample surface, secondary electrons can be emitted from the sample surface. 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 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 generated within the resist.

[0007] A charged particle device can be a means for generating, irradiating, projecting, and / or detecting one or more beams of charged particles. Within a charged particle device, multiple devices are provided for manipulating one or more beams of charged particles. Each device may include a substrate stack. Generally, improvements are needed in the fabrication and testing of devices including substrate stacks. Summary of the Invention

[0008] The embodiments provided herein disclose techniques for determining the relative alignment of substrates in a stack. The embodiments also include determining the relative alignment of the substrate stack and its PCB support.

[0009] According to a first aspect of the invention, a substrate stack comprising a plurality of substrates is provided, wherein: each substrate in the substrate stack includes at least one alignment opening group; the at least one alignment opening group in each substrate is aligned to allow a light beam to pass through a corresponding alignment opening in each substrate; and each substrate includes at least one alignment opening having a smaller diameter than the corresponding alignment openings in the other substrates.

[0010] According to a second aspect of the invention, a method is provided for determining the alignment of substrates in a substrate stack comprising a plurality of substrates, the method comprising: determining the positions of a plurality of light beams having passed through corresponding plurality of alignment openings defined in each substrate of the substrate stack; and determining relative x, y, and Rz alignments of at least two substrates in the substrate stack based on the determined positions; wherein: for each light beam path through the substrate stack, an alignment opening of one substrate in the light beam path has a smaller diameter than all or more other alignment openings of the corresponding one or more other substrates in the light beam path; and for each of at least two of the plurality of light beam paths, a different substrate in the light beam path has a smaller diameter than all or more other alignment openings of the corresponding one or more other substrates in the light beam path, such that for each of the at least two substrates in the substrate stack, there exists one or more light beam paths whose positions indicate the position of only said one substrate.

[0011] According to a third aspect of the invention, a computing system is provided, which is configured to determine the alignment of substrates in a substrate stack by performing the method according to the second aspect.

[0012] According to a fourth aspect of the invention, a tool is provided for obtaining data indicating the position of a light beam, the tool comprising: a stack holder configured to hold a substrate stack according to a first aspect; an irradiator configured to irradiate at least a portion of the surface of the substrate stack; and a photodetector configured to generate data indicating the position of the light beam based on a plurality of light beams that have passed through the substrate stack.

[0013] According to a fifth aspect of the invention, a system is provided that includes the tool according to the fourth aspect and the computing system according to the third aspect.

[0014] According to a sixth aspect of the invention, a method is provided for determining the alignment of substrates in a substrate stack having at least two substrates, wherein each substrate has a plurality of alignment openings aligned with corresponding alignment openings in other substrates of the substrate stack, such that a through-path exists through the substrate stack associated with each alignment opening in each substrate, the method comprising: determining the relative positions of a plurality of light beams, each light beam having passed through the substrate stack along an optical path via a corresponding through-path; and determining the relative xy and Rz alignment of the substrates in the substrate stack based on the determined positions; wherein: the alignment opening of one substrate in the substrate defining the through-path for the corresponding optical path through the through-path has a smaller diameter than the other alignment openings defining the through-path; and for each optical path, the diameter of the different substrates in the substrate stack is smaller than the diameter of the other alignment openings defining the corresponding through-path in the substrate stack.

[0015] According to a seventh aspect of the invention, a substrate stack including a substrate of a beam manipulator is provided, the substrate stack having at least two substrates, wherein each substrate has a plurality of alignment openings aligned with corresponding alignment openings in other substrates of the substrate stack, such that a through-channel is provided through the substrate stack associated with each alignment opening in each substrate, wherein each of the plurality of through-channels is used for the passage of a light beam, and the light beam is adapted to determine the relative x, y, and Rz alignment of the substrates in the substrate stack; wherein: the alignment opening of the through-channel of one substrate defining a corresponding optical path through the through-channel has a smaller diameter than the other alignment openings defining the through-channel; and the different substrates in the substrate stack have alignment openings having a smaller diameter than the other alignment openings defining the corresponding through-channels in the substrate stack.

[0016] According to an eighth aspect of the invention, a combination of a substrate stack and a printed circuit board (PCB) is provided, the substrate stack being provided on the PCB, wherein: an opening is defined in the PCB, the opening being configured to align with a through channel in the substrate stack for interacting with a stacked light source; and the surface of the PCB includes a plurality of alignment structures configured to interact with the PCB light source.

[0017] According to a ninth aspect of the invention, a combination of a printed circuit board (PCB) and a substrate stack is provided, wherein a plurality of through channels are defined in the substrate stack for openings for a beam path, the substrate stack being disposed on the PCB, wherein a plurality of alignment structures are in the surface of the PCB, the plurality of alignment structures being configured to interact with a light source for determining the alignment of the PCB.

[0018] According to a tenth aspect of the present invention, a method for determining the relative alignment of a substrate stack with a printed circuit board (PCB) is provided, wherein the substrate stack is disposed on the PCB, the method comprising: determining the positions of a first plurality of light beams having passed through a plurality of openings in the substrate stack and at least one opening in the PCB; determining the positions of a second plurality of light beams depending on a plurality of PCB alignment structures; and determining the relative x, y, and Rz alignment of the substrate stack and the PCB based on the determined positions of the first plurality of light beams and the second plurality of light beams.

[0019] According to an eleventh aspect of the invention, a computing system is provided, which is configured to determine the alignment of a PCB and substrate stack by performing the method according to the tenth aspect.

[0020] 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 illustration and example. Attached Figure Description

[0021] The above and other aspects of this disclosure will become more apparent from the description of exemplary embodiments taken in conjunction with the accompanying drawings.

[0022] Figure 1 This is a schematic diagram illustrating an exemplary charged particle beam inspection apparatus.

[0023] 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.

[0024] 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.

[0025] Figure 4 This is a schematic diagram showing a cross-section of a stack of two substrates according to an embodiment.

[0026] Figure 5 Four different relative positions of the light spot according to an embodiment are shown.

[0027] Figure 6A and Figure 6B The configuration of the alignment opening group according to an embodiment is shown. Detailed Implementation

[0028] Reference will now 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 the same reference numerals in different drawings denote the same or similar elements unless otherwise stated. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatuses and methods consistent with the aspects of the invention set forth in the appended claims.

[0029] The physical size of devices and the computing power of electronic devices can be reduced and the packaging density of circuit components such as transistors, capacitors, and diodes on IC chips can be significantly increased. This can be achieved by increasing resolution, thus enabling the manufacture of smaller structures. For example, the IC chip for a smartphone (the size of a thumbnail and available in 2019 or earlier) could include more than 2 billion transistors, each smaller than 1 / 1000th the size of a human hair. Therefore, it is not surprising that semiconductor IC manufacturing is a complex and time-consuming process with hundreds or thousands of individual 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 improve the overall process yield. For example, for a 50-step process (where steps can indicate the number of layers formed on the wafer), to achieve a 75% yield, each individual step must have a yield greater than 99.4%. If the yield of a single step is 95%, the overall process yield will be as low as 7-8%.

[0030] While high process yields are desirable in IC chip manufacturing facilities, maintaining high substrate (i.e., wafer) throughput (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 throughput, 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.

[0031] A Sequencing Array (SEM) comprises a scanning device and a detector assembly. The scanning device includes an illumination unit and a projection unit. The illumination unit includes an electron source for generating primary electrons, and the projection unit is used to scan a sample, such as a substrate, with one or more focused beams of primary electrons. The primary electrons interact with the sample and generate secondary electrons. As the sample is scanned, the detector unit captures these secondary electrons from the sample, allowing the SEM to produce an image of the scanned area of ​​the sample. For high-volume inspection, some inspection devices use multiple focused beams of primary electrons (i.e., multi-beams). The component beams of a multi-beam array can be referred to as sub-beams or beam waves. Multiple beams 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.

[0032] In multi-beam inspection setups, 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 arrive at the sample surface at substantially the same incident angle and / or at the desired pitch and / or at the desired location on the sample surface, it is necessary to manipulate sub-beam paths with a greater radial distance from the central axis to move them by a larger angle than those closer to the central axis. This stronger manipulation can lead to aberrations that result in blurred and defocused images of the sample substrate. In particular, for sub-beam paths not on the central axis, aberrations in the sub-beams can increase with radial displacement from the central axis because the manipulators of these sub-beam paths need to operate at higher voltages. This aberration can remain associated with secondary electrons when they are detected. Therefore, this aberration degrades the quality of the image produced during inspection.

[0033] The implementation of a known multi-beam inspection device is described below.

[0034] 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.

[0035] 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.

[0036] EFEM 30 includes a first load port 30a and a second load port 30b. EFEM 30 may include additional load ports. For example, the first load port 30a and the second load port 30b may receive a front-opening substrate transfer cassette (FOUP) containing a substrate (e.g., a semiconductor substrate or a substrate made of other materials) or a sample to be inspected (the substrate, wafer, and sample are collectively referred to below as the “sample”). One or more robotic arms (not shown) in EFEM 30 transport the sample to the load-locking chamber 20.

[0037] A load-locked chamber 20 is used to remove gas from the area surrounding the sample. This creates a vacuum with a local gas pressure lower than the ambient pressure. The load-locked chamber 20 can be connected to a load-locked vacuum pump system (not shown), which removes gas molecules 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 molecules 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, through which the sample can be examined. The electron beam tool 40 may include single-beam or multi-beam electron optics.

[0038] 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 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 component of the charged particle beam inspection apparatus, or it may be distributed across at least two 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 housing the electron beam inspection tool. Rather, it should be understood that the above principles can also be applied to other arrangements of equipment and other tools operating under a second pressure.

[0039] Now for reference Figure 2 , Figure 2 This is a schematic diagram illustrating an exemplary electron beam tool 40 including a multi-beam inspection tool, which is Figure 1This is 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, an aperture 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, aperture 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 an associated electron detection device 240. The primary projection device 230 may include an objective lens 231. The electron detection device 240 may include multiple detection elements 241, 242, and 243. The beam splitter 233 and the deflection scanning unit 232 can be positioned within the primary projection device 230.

[0040] Components used to generate the primary beam can be aligned with the primary electron-optical axis of device 40. These components may include: an electron source 201, a bore plate 271, a focusing 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 device 40.

[0041] The primary electron optical axis 204 is composed of the electron optical axis of the electron beam tool 40, which serves as the irradiation device. The secondary electron optical axis 251 is the electron optical axis of the electron beam tool 40, which serves as 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.

[0042] 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 as primary electrons from the cathode. The primary electrons are extracted or accelerated by the extractor and / or 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.

[0043] In this arrangement, the primary electron beam is multi-beamed upon its arrival at the sample, and preferably before its arrival at the projection device. This multi-beam electron beam can be generated from the primary electron beam in a variety of different ways. For example, the multi-beam can be generated by a multi-beam array located before the crossover, 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 can include multiple electron beam manipulation elements arranged in an array along 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 main beam path to generate a multi-beam path under-beam of the multi-beam array.

[0044] In operation, the aperture 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 detection point 221, 222, and 223 of the primary sub-beams 211, 212, and 213, thus reducing the inspection resolution. The aperture plate 271 may also be referred to as a Coulomb aperture array.

[0045] The focusing lens 210 is configured to focus the primary electron beam 202. The focusing lens 210 can be designed to focus the primary electron beam 202 into a parallel beam and properly incident on the source conversion unit 220. The focusing lens 210 can be a movable focusing lens, configured such that the position of its first principal plane is movable. The movable focusing lens can be configured to be magnetic. The focusing lens 210 can be an anti-rotation focusing lens and / or it can be movable.

[0046] Source conversion unit 220 may include an image forming element array, an aberration compensator array, a beam confinement aperture array, and a pre-bending micro-deflector array. The pre-bending micro-deflector array can deflect multiple primary sub-beams 211, 212, 213 of the primary electron beam 202 to properly enter the beam confinement 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-deflector 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) of the primary beam cross 203, one for each primary sub-beam 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-bundles 211, 212, and 213. The astigmatism compensator array may include multiple micro-stigmators to compensate for astigmatic aberrations of the primary sub-bundles 211, 212, and 213. The beam-limiting aperture array may be configured to limit the diameter of each primary sub-bundle 211, 212, and 213. Figure 2 Three primary sub-bundles 211, 212, and 213 are shown as an example, and it should be understood that the source conversion unit 220 can be configured to form any number of primary sub-bundles. The controller 50 can be connected to... Figure 1 The various components of the charged particle beam inspection device 100 (such as the source conversion unit 220, electronic inspection device 240, primary projection device 230, or motorized worktable 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 control the operation of the charged particle beam inspection device (including charged particle multi-beam device).

[0047] The focusing lens 210 can also be configured to adjust the current of the primary sub-bundles 211, 212, 213 of the source conversion unit 220 by changing the focusing capability of the focusing lens 210. Alternatively, or additionally, the current of the primary sub-bundles 211, 212, 213 can be changed by changing the radial dimension of the beam-limiting aperture within the beam-limiting aperture array corresponding to each primary sub-bundle. If the focusing lens is movable and magnetic, the off-axis sub-bundles 212 and 213 can cause the source conversion unit 220 to be illuminated at a rotational angle. The rotational angle changes with the focusing capability of the movable focusing lens or the position of the first principal plane. The focusing lens 210, as an anti-rotation focusing lens, can be configured to maintain a constant rotational angle when the focusing capability of the focusing lens 210 changes. This movable focusing lens 210 can also cause the rotational angle to remain unchanged when the focusing capability of the focusing lens 210 and the position of its first principal plane change.

[0048] Objective 231 can be configured to focus sub-beams 211, 212 and 213 onto sample 208 for inspection, and can form three probe points 221, 222 and 223 on the surface of sample 208.

[0049] Beam splitter 233 may be, for example, a Wien filter comprising an electrostatic deflector that generates an electrostatic dipole field and a magnetic dipole field. Figure 2 (Not shown in the image). In operation, beam splitter 233 can be configured to apply electrostatic forces to the individual electrons of primary sub-bundles 211, 212, and 213 via an electrostatic dipole field. The electrostatic forces are equal in magnitude but opposite in direction to the magnetic forces applied to the individual electrons by the magnetic dipole field of beam splitter 233. Therefore, primary sub-bundles 211, 212, and 213 can pass through beam splitter 233 at least substantially straight with at least substantially zero deflection angle.

[0050] In operation, deflection scanning unit 232 is configured to deflect primary sub-beams 211, 212, and 213 to scan detector points 221, 222, and 223 on various scanning regions within the surface portion of sample 208. In response to the incidence of primary sub-beams 211, 212, and 213 or detector 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. 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 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. The secondary projection device 250 then focuses the paths of the secondary electron beams 261, 262, and 263 onto multiple detection areas 241, 242, and 243 of the electron detection device 240. The detection areas can be individual detection elements 241, 242, and 243 arranged to detect the corresponding secondary electron beams 261, 262, and 263. The detection areas generate corresponding signals, which are sent to the controller 50 or a signal processing system (not shown), for example, to construct an image of the corresponding scanned area of ​​the sample 208.

[0051] Detection elements 241, 242, and 243 can detect corresponding secondary electron beams 261, 262, and 263. When the secondary electron beams are incident using 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.

[0052] 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 communicatively coupled to an electronic inspection device 240 that allows signal communication, 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 therefrom. 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 such as brightness and contrast of the acquired image. The memory may be a storage medium such as a hard disk, flash drive, cloud storage, random access memory (RAM), or other types of computer-readable storage. The memory can be coupled to the image acquisition unit and can be used to save the scanned raw image data as both the original image and the post-processed image.

[0053] 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 memory. The single image may be an original image that can be divided into multiple regions. Each region may include an imaging region containing features of sample 208. The acquired images may include multiple images of a single imaging region of sample 208 sampled multiple times within a time period. 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 sample 208.

[0054] The controller 50 may include 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 of each of the primary sub-beams 211, 212, and 213 incident on the sample surface to reconstruct an image of the sample structure under examination. 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 exist in the sample.

[0055] The controller 50 can control the motorized stage 209 to move the sample 208 during inspection. At least during sample inspection, the controller 50 enables the motorized stage 209 to move the sample 208 in a preferably continuous direction (e.g., at a constant speed). The controller 50 can control the movement of the motorized stage 209 such that it varies the speed of movement of the sample 208 according to various parameters. For example, the controller can control the stage speed (including its direction) depending on the characteristics of the inspection steps in the scanning process.

[0056] although Figure 2 The device 40 is shown to use three primary electron sub-beams, but it should be understood that the device 40 may use two or more primary electron sub-beams.

[0057] Now for reference Figure 3 , Figure 3 It is shown Figure 1 This is a schematic diagram of an exemplary multi-beam apparatus with an exemplary configuration of the source conversion unit of an exemplary charged particle beam inspection device. The apparatus 300 may include an electron source 301, a pre-beam forming aperture array 372, and a focusing lens 310 (similar to...). Figure 2 (Converging 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 electron source 301, pre-beam forming aperture array 372, and focusing lens 310 can be components of the irradiation device included in the apparatus 300. The source conversion unit 320 and objective lens 331 can be components of the projection device included in the apparatus 300. The source conversion unit 320 can 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-limited aperture array is a beam-limited aperture array 321. Figure 2The pre-bent micro-deflector array is a pre-bent micro-deflector array 323. An electron source 301, a pre-beamforming aperture array 372, a focusing lens 310, a source conversion unit 320, and an objective lens 331 are aligned with the primary electron optical axis 304 of the device. The electron source 301 typically generates a primary electron beam 302 along the primary electron optical axis 304 and has source crossovers (virtual or real) 301S. The pre-beamforming 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 sub-beam aberrations due to the interaction between electrons in different sub-beam paths. Through the pre-beamforming aperture array 372 of the pre-beamforming 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-bundles and their paths are mentioned in the preceding and following descriptions, it should be understood that the description is intended for application to devices, tools, or systems with any number of sub-bundles.

[0058] 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. Source conversion unit 320 may also include an image-forming element array 322 with image-forming micro-deflectors 322_1, 322_2, and 322_3. A corresponding micro-deflector is associated with the path of each sub-beam. Micro-deflectors 322_1, 322_2, and 322_3 are configured to deflect the paths of 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 cross 301S. The virtual image is projected onto the sample 308 by objective lens 331, forming detection points thereon, which are three detection points 391, 392, and 393. Each detection 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-bundle. Aberrations in each sub-bundle typically occur at probe points 391, 392, and 393, which will form the sample surface. The aberration compensator array 324 may include an array of field curvature compensators (not shown) with microlenses. The field curvature compensators and microlenses are configured to compensate for sub-bundles exhibiting significant field curvature aberrations at probe points 391, 392, and 393. The aberration compensator array 324 may include an array of astigmatism compensators (not shown) with micro-astigmatism correction devices. The micro-astigmatism correction devices are controlled to operate on the sub-bundles to compensate for astigmatic aberrations otherwise present at probe points 391, 392, and 393.

[0059] 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 focusing lens 310 can guide the paths of the sub-beams onto the beam confinement aperture array 321. The focusing 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 sub-beam confinement aperture array 321.

[0060] The image forming element array 322, aberration compensator array 324, and pre-bending micro-deflector array 323 may include multi-layer sub-beam manipulation devices, some of which may be in the form of, for example, micro-deflectors, microlenses, or micro-astigmatism correction devices or arrays.

[0061] In the source conversion unit 320, 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 micro-deflector 322_1, therefore the path of sub-beam 311 may not be deflected by micro-deflector 322_1.

[0062] 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. The deflection angles of sub-beams 311 to 313 are adjusted by objective lens 311 to reduce off-axis aberrations at the three detection points 391 to 393. The three deflected sub-beams thus pass through or approach the front focal point of objective lens 331.

[0063] Figure 2 and Figure 3 At least some of the aforementioned components may be referred to individually or in combination as manipulator arrays or manipulators, because they manipulate one or more bundles or sub-bundles of charged particles.

[0064] The aforementioned multi-beam inspection tool includes a multi-beam charged particle device with a single charged particle source, which may be referred to as a multi-beam charged particle optical device or a multi-beam charged particle system. The multi-beam charged particle device includes an irradiation device and a projection device. The irradiation device generates multiple beams of charged particles from an electron beam from the source. The projection device projects multiple beams of charged particles onto the sample. At least a portion of the sample surface is scanned using the multiple beams of charged particles.

[0065] A multi-beam charged particle device may include one or more beam manipulators. In a single-beam charged particle device, there may be a beam manipulator for manipulating the beam path. In a multi-beam charged particle device, there may be an array of beam manipulators (i.e., a manipulator array) for manipulating multiple sub-beams. Each beam manipulator may be, for example, a MEMS device or any other type of device / structure for manipulating the charged particle path. Each beam manipulator may include one or more substrates. An opening may exist through each beam manipulator for the sub-beam path through the beam manipulator. The periphery of the through-channel defined by the opening may have one or more electrodes. Each beam manipulator is configured to manipulate (such as a lens (e.g., focusing) and / or deflect) the sub-beam path through its opening. The beam manipulators may be arranged in an N×M array. N may be, for example, between 2 and 20 (such as 5). For example, M may be between 2 and 20 (such as 5). However, N and M can have any value, and each of N and M may be in the thousands.

[0066] The manipulator array, as a beam manipulator array, can be formed as a stack of substrates, referred to as a substrate stack. Each substrate in the substrate stack may include multiple openings (i.e., apertures) for providing sub-beam paths through the substrate stack. The multiple openings may be referred to as beam path openings. Each beam manipulator in the manipulator array can be constructed by fixing (e.g., combining) two or more substrate groups together, wherein each substrate group is substantially directly before and / or after another substrate group along the beam path. Each substrate group may include one or more substrates.

[0067] The performance of each beam manipulator depends on the relative alignment of the substrates that are bonded together to form the beam manipulator. In particular, substantial misalignment between corresponding beam path openings in different substrate groups will distort, or in severe cases prevent one or more sub-beams from passing through the path of the substrate stack.

[0068] The embodiments provide techniques for determining the relative alignment of substrate groups fixed together. The embodiments are described below with reference to multiple substrate groups fixed together to form a manipulator array including a beam manipulator array. However, the embodiments also include multiple substrate groups fixed together to form a single beam manipulator. The embodiments also include multiple substrate groups fixed together for any application.

[0069] As described above, each substrate includes multiple openings for providing sub-beam paths. In addition to the beam path openings, embodiments include forming multiple alignment openings in each substrate. One alignment opening on one of the main surface sides of the substrate stack is illuminated. The location and diameter of the alignment openings are such that the relative alignment of the substrates in the substrate stack depends on the relative position of the light beam passing through the alignment openings in the substrate stack. Therefore, the relative alignment of the substrates in the substrate stack can be determined by examining the light beam passing through the alignment openings.

[0070] Figure 4 This is a schematic diagram showing a cross-section of a stack of two substrates according to an embodiment.

[0071] Figure 4 The substrate stack includes a first substrate 404 and a second substrate 405. The first substrate 404 may be referred to as the upper beam substrate 404 because it is the first substrate to be irradiated by charged particles when the substrate stack is irradiated by the light source 418. The second substrate may be referred to as the lower beam substrate. The first substrate 404 includes first alignment opening groups 412, 413, and 414. The first substrate 404 also includes second alignment opening groups 415, 416, and 417. The first substrate 404 also includes beam path openings 427 for the charged particle beam paths of multiple beams of charged particles. The beam path openings 427 are patterned in the main surface of the first substrate 404 between the first and second alignment opening groups.

[0072] The second substrate includes first alignment opening groups 406, 407, and 408. The second substrate also includes second alignment opening groups 409, 410, and 411. The second substrate 405 also includes beam path openings 426 for charged particle beam paths of multiple charged particles. The beam path openings 426 are patterned in the main surface of the second substrate 405 between the first and second alignment opening groups.

[0073] The second substrate 405 can be an aperture array. When substrate stacking is used in a multi-beam charged particle device, the aperture array is the main surface of the substrate stack irradiated by charged particles. All beam path openings of the second substrate 405 may have a narrower diameter than the corresponding beam path openings of the first substrate 404. The beam path openings in the aperture array define sub-beams. The size and shape of the sub-beams will also depend on the beam manipulators along the beam path openings.

[0074] In this embodiment, the second substrate 405 may be referred to as a reference substrate. A reference substrate is a substrate in which the positions of other substrates in the substrate stack are defined relative to it. Although any substrate in the substrate stack can be used as a reference substrate, the reference substrate is preferably a substrate that includes an aperture array. This is because a substrate that includes an aperture array defines a sub-bundle and therefore has a greater impact on the performance of the manipulator array compared to any other substrate in the substrate stack.

[0075] exist Figure 4 In this process, the diameter of each light spot 402 depends on the diameter of the beam portion opening in the second substrate 405. The diameter of each light spot 402 does not depend on the diameter of the beam portion opening in the first substrate 404, because the beam path opening in the first substrate 404 has a larger diameter than the beam path opening in the second substrate.

[0076] In the first alignment opening group in the second substrate 405, alignment opening 407 has a narrower diameter than alignment openings 406 and 408. Alignment opening 407 may be located between the other alignment openings 406 and 408. Similarly, in the second alignment opening group in the second substrate 405, alignment opening 410 has a narrower diameter than alignment openings 409 and 411. Alignment opening 410 may be located between the other alignment openings 409 and 411.

[0077] In the first alignment opening group in the first substrate 404, alignment openings 412 and 414 have a narrower diameter than alignment opening 413. Alignment opening 413 may be located between the other alignment openings 412 and 414. Similarly, in the second alignment opening group in the first substrate 404, alignment openings 415 and 417 have a narrower diameter than opening 416. Alignment opening 416 may be located between the other alignment openings 415 and 417.

[0078] The diameters of all the alignment openings 412, 414, 415, 417, 407, and 410 can be substantially the same. Their diameters can range, for example, from 100 µm to 1500 µm.

[0079] The diameters of all alignment openings 413, 416, 406, 408, 409, and 411 can be substantially the same. Their diameters can, for example, range from 200 µm to 2000 µm.

[0080] Light source 418 is configured to illuminate alignment openings on the exposed main surface of the first substrate 404. When the exposed main surface of the first substrate 404 is illuminated, optical beam 401 can pass through a first alignment opening group in the first substrate 404 and the second substrate 405. Optical beam 402 can also pass through beam path openings in the first substrate 404 and the second substrate 405. Optical beam 403 can also pass through a second alignment opening group in the first substrate 404 and the second substrate 405.

[0081] For each beam that has passed through the alignment opening, the spot size of the beam can depend only on the minimum diameter of the alignment opening through which the beam has passed. Furthermore, the position of the spot can depend only on the position of the substrate including the alignment opening with the minimum diameter.

[0082] Therefore, for the first substrate 404, the alignment openings 412, 414, 415, and 417 can each determine the spot size of the light beam passing through these alignment openings. This is because the alignment openings 412, 414, 415, and 417 of the first substrate 404 all have a narrower diameter than the corresponding alignment openings 406, 408, 409, and 411 of the second substrate 405. Therefore, the position of the light beam passing through these alignment openings can depend only on the position of the first substrate 404, and not on the position of the second substrate 405.

[0083] Similarly, for the second substrate 405, alignment openings 407 and 410 each determine the spot size of the light beam passing through these alignment openings. This is because the alignment openings 407 and 410 of the second substrate 405 both have a narrower diameter than the corresponding alignment openings 413 and 416 of the first substrate 404. Therefore, the position of the light beam passing through these alignment openings can depend only on the position of the second substrate 405, and not on the position of the first substrate 404.

[0084] Alignment openings 407 and 410 can be referred to as reference openings because they are located in the reference substrate and define the size and position of the light spot. Alignment openings 412, 414, 415, and 417 can be referred to as comparison openings because they are not located in the reference substrate and define the size and position of the light spot.

[0085] The embodiments can determine the relative alignment of substrates in a substrate stack based on the relative positions of light beams that have passed through the alignment openings. Specifically, the relative positions of light spots generated by reference openings 407 and 410 and light spots generated by comparison openings 412, 414, 415, and 417 can be used to determine the relative alignment of the first substrate 404 and the second substrate 405 (i.e., the reference substrate).

[0086] A light beam can form a spot of light on the surface of a camera's light detector (such as a camera). The light detector... Figure 4 Not shown. Each light spot can indicate the position of a beam of light that has passed through the substrate stack. A photodetector can generate a signal corresponding to the formed light spot. The photodetector may include a processor configured to generate data indicating the position of the light spot from the generated signal. The photodetector can transmit the signal to an external processor capable of generating the data indicating the position of the light spot. Embodiments include processing the data indicating the position of the light spot to compensate for any tilt between the substrate stack and the optical axes of the photodetector. The data indicating the position of the light spot can be provided to and used by an image generator to generate one or more images. The relative alignment of the substrate can be determined based on the relative positions of the light spots in one or more images. However, embodiments also include automatically using the data indicating the position of the light spot to determine the alignment of the substrate without generating any images.

[0087] All processes used to determine substrate alignment based on the obtained data indicating the position of the indicator spot can be performed by a computing system. The computing system may include an image generator.

[0088] The embodiments include a tool for generating data indicating the position of a light spot. The tool may include a holder configured to hold a stack of substrates. The tool may include an irradiator configured to irradiate at least a portion of the main surfaces of one of the substrate stacks. The tool may include one or more photodetectors for detecting the position of the light beam. The tool may include the aforementioned computational system for determining substrate alignment based on the obtained data indicating the position of the light spot. Alternatively, the computational system may be located remotely from the tool.

[0089] exist Figure 4 In this design, each substrate has a substantially planar structure. The plane of each substrate can be defined as being in the xy-plane (in Cartesian coordinate geometry). The substrates are stacked in a direction substantially orthogonal to the xy-plane (i.e., stacked along the z-axis in the z-direction). The first substrate 404 is shown properly aligned with the second substrate 405. In particular, the main surfaces of the substrates are in substantially parallel planes, and the beam path openings in the substrates have corresponding positions.

[0090] The alignment aperture groups in each substrate are configured such that reference apertures 407 and 410 and comparison apertures 412, 414, 415, and 417 are arranged along a direction (e.g., in the x-direction) in the plane of the substrate stack. The alignment aperture group in the first alignment aperture group in each substrate is arranged such that reference aperture 407 is located between the two comparison apertures 412 and 414. When the first and second substrates are properly aligned, the light spot corresponding to reference aperture 407 can be equidistant from the light spots corresponding to comparison apertures 412 and 414. Similarly, the alignment apertures in the first alignment aperture group in each substrate are arranged such that reference aperture 410 is located between the two comparison apertures 415 and 417. When the first and second substrates are properly aligned, the light spot corresponding to reference aperture 410 can be equidistant from the light spots corresponding to comparison apertures 415 and 417. In each substrate, a beam path aperture can be aligned with the first and second alignment aperture groups along an axis (such as the x-axis). The beam path aperture can be equidistant from each of the first and second alignment aperture groups.

[0091] In the plane of the substrate and along a direction orthogonal to the x-axis (i.e., along the y-axis), the alignment openings in each alignment opening group can have a displacement that is substantially zero.

[0092] Figure 5A plan view shows examples of four different relative positions of light spots 401, 402, and 403 that have passed through aligned openings in a substrate stack comprising two substrates. These examples of four different relative positions of the light spots can correspond to... Figure 4 The first substrate 404 and the second substrate 405 are shown in four different relative alignments.

[0093] First example 501 illustrates a spot pattern when there is proper alignment between the first substrate 404 and the second substrate 405. Second to fourth examples illustrate spot patterns with three different types of misalignment.

[0094] The relative positions of the light spots in the first example 501 indicate that the first and second substrates are properly aligned in x, y, and Rz (where Rz is the amount of rotation about the z-axis), as described above for... Figure 4 The above. From the first alignment opening group ( Figure 5 The leftmost one) and the second aligned opening group ( Figure 5 The light spots (most rightmost in the diagram) are all substantially aligned along the x-axis, indicating that the substrates are substantially aligned relative to the y-direction and the rotational position Rz. That is, there is no substantial misalignment of the substrates in the y-direction, and Rz is appropriate. The light spots from both the first and second alignment aperture groups are substantially equally spaced in the x-direction. This indicates that the two substrates are substantially aligned in the x-direction. That is, there is no substantial misalignment between the substrates in the x-direction.

[0095] The relative positions of the light spots generated in the second example 502 indicate that the first and second substrates are properly aligned in the y and Rz directions, but misaligned in the x direction. The light spots from the first and second alignment aperture groups are both substantially located on the x-axis, indicating that the substrates are substantially aligned relative to the y-direction and the Rz rotational position. However, the light spots detected from the first and second alignment aperture groups are not unequally spaced along the x-axis; that is, the middle light spot corresponding to each alignment aperture group is displaced in the same direction and with the same magnitude from the center position between the light spots. This indicates a misalignment between the two substrates in the x-direction.

[0096] The relative positions of the light spots generated in the third example 503 indicate that the first and second substrates are properly aligned in the x and Rz directions, but misaligned in the y direction. Some, but not all, of the light spots from the first and second alignment aperture groups are located on the x-axis; in particular, the middle light spot in each group has a similar displacement and directional displacement in the y direction relative to the other light spots in each group. This indicates that there is a misalignment of the substrates in the y direction. This light spot pattern indicates rotational alignment in the Rz direction. The light spots from both the first and second alignment aperture groups are substantially equally spaced in the x-direction, indicating that the substrates are aligned in the x-direction. That is, there is no substantial misalignment of the two substrates in the x-direction.

[0097] The relative positions of the light spots generated in the fourth example 504 indicate that the first and second substrates are properly aligned in the x and y directions, but misaligned in the Rz direction. The light spot corresponding to the first alignment aperture group is aligned in the x direction, and the center alignment aperture is displaced by an amount in the y direction, which can be referred to as the positive y direction. The light spot corresponding to the second alignment aperture group is aligned in the x direction, and the center aperture is displaced by the same amount in the y direction as the center point of the first alignment aperture group, but in the opposite y direction (i.e., the negative y direction). This similar displacement magnitude in the opposite directions of the center alignment apertures of the two groups indicates that the substrates are aligned in the y direction and rotated in the Rz direction (i.e., about the z-axis). That is, the two substrates are misaligned in the Rz direction. The light spots from both the first and second alignment aperture groups are substantially equally spaced in the x direction, which indicates that the two substrates are substantially aligned in the x direction; that is, the substrates are not substantially misaligned in the x direction.

[0098] Therefore, the relative position of the light spot can be used to determine the relative positions of the first substrate 404 and the second substrate 405 in x, y, and Rz. Actual substrate misalignment in x, y, and / or Rz can be defined as comprising multiple individual misalignment components, each located in one of x, y, and Rz. For each substrate in the substrate stack other than the reference substrate, a tolerance level can be set for the relative alignment components of each substrate in x, y, and Rz relative to the reference substrate. This tolerance level can be referred to as the positioning degree of freedom for each substrate. The tolerance level can be different for each substrate in the substrate stack. If the relative alignment components of all substrates in the substrate stack relative to the reference substrate are within the set tolerance level, then the substrate stack can be determined to be within the alignment performance specifications.

[0099] For each substrate in the substrate stack, there may be at least one beam path through the substrate stack, and for that at least one beam path, the spot size and position of at least one beam may depend only on the position of the substrate. That is, for each substrate in the substrate stack and on the at least one beam path, the substrate may include at least one alignment opening having a diameter narrower than all corresponding alignment openings of the other substrates in the substrate stack.

[0100] For different beam paths, the narrowest diameter of the alignment aperture, which defines the spot size, can vary between different substrates. This allows the position of each substrate in a substrate stack to be individually identified by at least one light spot targeting the substrate.

[0101] The number of alignment openings in each alignment opening group can depend on the number of substrates in the substrate stack. The number of alignment openings in each alignment opening group can be greater than or equal to the number of substrates in the substrate stack, such that for each substrate, there is at least one light spot corresponding only to its location. In one arrangement, there is at least one more opening than the number of substrates in the substrate stack.

[0102] The embodiments can be used to determine the relative alignment of any number of substrates in a substrate stack. For example, the number of substrates in a substrate stack can be from 2 to 20.

[0103] Although embodiments include only one alignment aperture group, it is preferable to have at least two alignment aperture groups. Preferably, the two alignment aperture groups are located at opposite ends of the main surface of the substrate. For example, the two alignment aperture groups may be located at opposite ends of the x-axis, such as... Figure 5 As shown, the relatively large spacing between the alignment opening groups increases the accuracy of Rz alignment determination.

[0104] As described above, alignment aperture groups can be positioned on either side of the beam path opening. Each alignment aperture group can be spaced considerably from the beam path opening such that the alignment apertures do not affect or otherwise influence the effective area of ​​each substrate, as required by the beam manipulator.

[0105] Examples can be used to determine whether two or more substrates in a bonded substrate group are aligned in the x, y, and Rz directions within performance specifications. If the substrate alignment is not within performance specifications, the substrate group can be deemed unusable, resulting in a defect-free final product including the substrate group. Alternatively, it can be determined to debond the substrates and re-bond them with adjusted alignment.

[0106] The embodiments also allow for the determination of whether a substrate stack comprising two or more substrate groups bonded together is properly aligned in the x, y, and Rz directions. If the substrate groups are not properly aligned, a discarded substrate stack can be identified, resulting in a defect-free final product comprising the substrate stack. Alternatively, it can be determined that the substrate groups be debonded and re-bonded with adjusted alignment.

[0107] For each substrate group comprising multiple substrates, the substrates can be arranged such that for each substrate in the substrate group, there exists at least one beam path through the substrate group, with respect to which the spot size and position of at least one beam depends only on the position of the substrate. Alternatively, the substrates can be configured such that for some substrates, there is no beam spot size and position dependent on the substrate position. This may be appropriate, for example, when the accuracy of the x, y, and Rz positions of some substrates in the substrate group is not critical to all substrates in that substrate group.

[0108] The embodiments also include determining the relative alignment of the substrates or substrate groups in x, y, and Rz before the substrates or substrate groups are bonded together. The spot position can be used to adjust the position of the substrates or substrate groups in x, y, and Rz so that the substrates or substrate groups are properly aligned before they are bonded together.

[0109] The configuration (i.e., arrangement) of the alignment openings in each alignment opening group can be substantially the same. The alignment openings in each alignment opening group can be configured such that the alignment openings are arranged on a substantially straight line. Alternatively, the alignment openings in each alignment opening group can be configured such that the alignment openings are arranged on multiple substantially straight lines.

[0110] Figure 6A Possible configurations of alignment aperture groups are shown. The alignment apertures in each alignment aperture group are configured such that they are aligned along two orthogonal, substantially straight lines. The orthogonal lines along which the alignment marks are aligned are parallel to the x and y axes. It should be noted that... Figure 6A Only exemplary relative positions of the aligned openings are shown. Figure 6A No indication is given of the relative diameter (i.e., size) of the alignment openings, because these differ between the substrates in the substrate stack.

[0111] Figure 6A The alignment aperture group shown can be used in a substrate stack comprising two or more substrates. For example, the alignment aperture group can be used in a substrate stack comprising five substrates. One substrate in the substrate stack can be a reference substrate relative to which it determines the alignment of the other substrates. As previously described, the reference substrate can be a substrate for which the beam path aperture is an aperture array, and the sub-beam path is defined by the aperture array. Alignment aperture 601 can be the narrowest among the reference substrates. Therefore, alignment aperture 601 can be referred to as the reference aperture. For all alignment apertures 602, 603, 604, 605, 606, and 607, the narrowest alignment aperture is the substrate other than the reference substrate. Therefore, all alignment apertures 602, 603, 604, 605, 606, and 607 are referred to as comparison apertures.

[0112] Alignment openings 603 and 604 can both be the narrowest in the same substrate, thus they are comparative openings for the same substrate. The advantage of this is that when the substrate including these comparative openings is correctly aligned with the reference substrate, the light spots generated by alignment openings 601, 603, and 604 are all aligned in the x-direction and equally spaced. Therefore, the previously referenced... Figure 5 The described technique can be readily used to identify any misaligned component.

[0113] Similarly, alignment openings 606 and 607 can both be comparison openings for the same substrate, unlike substrates with alignment openings 603 and 604 as comparison openings. When a substrate with alignment openings 606 and 607 as comparison openings is correctly aligned with a reference substrate, the light spots generated by alignment openings 601, 606, and 607 are all aligned in the y-direction and equally spaced. Therefore, the aforementioned reference... Figure 5 The described technique can be readily used to identify any misaligned component.

[0114] Alignment opening 602 can be a comparison opening for a substrate for which none of the other alignment openings are comparison openings. Therefore, only one light spot will indicate the position of the substrate, for which alignment opening 602 is a comparison opening. The displacement of the light spots from the comparison opening and the reference opening in the x and y directions can be determined. Thus, the relative alignment of the substrate with the reference substrate, for which alignment opening 602 is a comparison opening, can be determined.

[0115] Similarly, alignment opening 605 can be a comparison opening for a substrate for which none of the other alignment openings are comparison openings. Therefore, only one light spot will indicate the position of the substrate, for which alignment opening 605 is a comparison opening. The displacement of the light spots from the comparison opening and the reference opening in the x and y directions can be determined. Thus, the relative alignment of the substrate with a reference substrate, for which alignment opening 605 is a comparison opening, can be determined.

[0116] For substrates with more than one comparison opening, the relative alignment with the reference substrate can be determined more precisely. However, when only one comparison opening exists for a substrate, it is still possible to determine whether the substrate alignment meets performance specifications. Therefore, substrates in a substrate stack with the most critical alignment tolerances preferably have more than one comparison opening. It may be appropriate for the other substrates in the substrate stack to have only one comparison opening, which advantageously reduces the number of alignment openings required.

[0117] Figure 6A The alignment opening group shown can preferably be used in conjunction with another alignment opening group. The other alignment opening group can be, for example, with... Figure 6A As shown or as Figure 6B The alignment openings shown are the same. Figure 6B The alignment opening assembly shown can be Figure 6A The alignment opening group shown is essentially a mirror image. That is, the positions of the alignment openings in different alignment opening groups can have reflective symmetry about the y-axis. Figure 6A and 6B The alignment openings can be set at opposite ends of the main surface of the substrate. Figure 6BThe alignment opening group in the middle can be configured such that alignment openings 601′, 602′, 603′, 604′, 605′, 606′ and 607′ provide alignment with each substrate. Figure 6A The corresponding relationship between the reference and comparison openings 601, 602, 603, 604, 605, 606 and 607 is the same.

[0118] The use of multiple alignment aperture groups increases the number of comparison apertures provided. This increases both the accuracy at which any misalignment can be determined and the number of substrates that can provide one or more comparison apertures.

[0119] Additional alignment openings can be added Figure 6A and Figure 6B In the two alignment opening groups shown, each additional alignment opening will provide a comparison opening for the substrate in the substrate stack. Preferably, each additional alignment opening is positioned in the y-direction or the x-direction such that it is displaced from the reference opening only in the x-direction or only in the y-direction. However, the alignment opening can be positioned in the alignment opening group at any location, provided that the relative position of the alignment opening with respect to the reference opening 407 can at least be determined. In particular, embodiments include providing along relative to Figure 6A and Figure 6B The other aligned openings are located on the diagonals of the x and y directions.

[0120] Substrate stacks are typically disposed on a printed circuit board (PCB). The PCB provides both physical support for the substrate stack and electrical connections to the substrates within the stack. The PCB can also support other components besides the substrate stack. Therefore, the manufacturing process of the device can include processes for positioning the substrate stack on the PCB. Examples include techniques for determining whether the substrate stack is properly positioned on the PCB. The PCB is provided with a PCB alignment structure that can be used to determine the relative alignment of the substrate stack and the PCB.

[0121] A PCB can be a planar structure with an upper main surface and a lower main surface. Substrate stacks can be disposed on the upper main surface of the PCB. The size of the PCB's main surface can be larger than the corresponding size of the main surfaces of all substrates in the substrate stack.

[0122] As previously described, the substrate stack may include multiple alignment aperture groups and beam path apertures. A single large aperture through the PCB may exist, allowing multiple beams of charged particles to pass through both the beam path apertures and the single aperture through the PCB during use. The single aperture in the PCB may be large enough for the beam to pass through both the alignment aperture groups and the PCB. Alternatively, the PCB may include additional apertures such that all beams passing through the substrate stack can also pass through the PCB.

[0123] As described above, the PCB is provided with a PCB alignment structure for determining the relative alignment of the substrate stack and the PCB. The PCB alignment structure may include markings disposed on the upper main surface of the PCB. For example, the markings may be optical reflectors such as reference marks. The markings may have a characteristic pattern. Alternatively, the PCB alignment structure may be a through-channel through the PCB.

[0124] Each PCB alignment structure may be spaced apart from an area on the upper main surface of the PCB that is covered by the substrate stack after assembly. Therefore, when the substrate stack is on the PCB, each PCB alignment structure is not covered by the substrate stack. The PCB alignment structures may be arranged such that when the substrate stack is correctly aligned and positioned on the PCB, the PCB alignment structures are substantially linearly aligned in a plan view with the alignment openings in the stack. In one embodiment, the substrate stack is arranged between at least two PCB alignment structures, and the PCB alignment structures are substantially linearly aligned in the x-direction with the alignment openings in the substrate stack.

[0125] Examples include determining the relative alignment of the PCB and substrate stack by illuminating the upper main surfaces of the stack and the PCB. As previously described, the illumination of the beam, depending on the location of the substrate stack, can pass through both the PCB and the alignment aperture group and / or the beam path opening of the substrate stack. The location of the substrate stack can be determined based on the position of the beam passing through the alignment aperture group and / or the beam path opening.

[0126] The illumination will also generate reflected beams from each PCB alignment structure, which acts as an optical reflector. The position of the PCB can be determined based on the position of the reflected beams.

[0127] The illumination will also generate multiple transmitted light beams that pass through each PCB alignment structure, which is an opening in the PCB. The position of the PCB can be determined based on the position of the transmitted light beams.

[0128] The relative alignment of the PCB and substrate stack on x, y, and Rz can be determined based on the relative positions of the light spots from the beams that depend on the position of the substrate stack and the light spots from the beams that depend on the position of the PCB.

[0129] A spot of light from a transmitted beam can be generated in the same plane as a spot of light from a beam that has already passed through the substrate stack. A spot of light from a reflected beam can be generated in a different plane than a spot of light from other beams.

[0130] A light beam can form a spot on the surface of one or more photodetectors (such as a camera). Each spot can indicate the position of the light beam that has passed through the substrate stack or, depending on the position of the PCB alignment structure. Spot signals can be generated by each photodetector to which the spot is incident. Each spot signal can indicate spot position data generated by the photodetector. The data indicating the spot position can be generated and / or captured by one or more photodetectors. Embodiments include processing the data indicating the spot position to compensate for any tilt between the PCB and / or substrate stack and the optical axes of one or more photodetectors. The data representing the spot position can be provided to and used by an image generator to generate one or more images, and the relative alignment of the substrate stack and PCB can be determined based on the relative positions of the spots in the one or more images. However, embodiments also include automatically using the data indicating the spot position to determine the relative alignment of the substrate stack and PCB.

[0131] All processes used to determine the alignment of the PCB and substrate stack based on the obtained data indicating the position of the indicator spot can be performed by a computing system. The computing system may include an image generator.

[0132] The embodiments include a tool for generating data indicating the position of a light spot. The tool may include a holder configured to hold a PCB having a substrate stack thereon. The tool may include an illuminator configured to illuminate at least a portion of the main surfaces of the PCB and the substrate stack. The tool may include one or more photodetectors for detecting the position of the light beam. The tool may include the aforementioned computational system for determining the alignment of the PCB and the substrate stack based on the obtained data indicating the position of the light spot. Alternatively, the computational system may be located remotely from the tool.

[0133] The implementation can be used to determine whether a PCB and substrate stack that have been bonded together are aligned in the x, y, and Rz directions within the performance specifications. If the alignment is not within the performance specifications, the PCB and substrate stack can be discarded, resulting in a defect-free final product including the substrate stack on the PCB. Alternatively, it can be determined to debond the substrate stack and PCB. The substrate stack and PCB can then be re-bonded with the corrected alignment.

[0134] The embodiments also include techniques for determining the relative Rx, Ry, and z positions of substrates in a substrate stack.

[0135] As previously described, each substrate in the substrate stack has a substantially planar structure that is substantially in the xy plane. The substrates in the substrate stack are stacked in the z-direction. The rotational displacement about the x-direction is called Rx. The rotational displacement about the y-direction is called Ry. The upper main surface of each substrate in the substrate stack can be substantially planar (e.g., rectangular). The sides of the rectangle can be substantially in the x-direction and the y-direction, respectively.

[0136] For each substrate in the substrate stack, its dimensions in the x and y directions can be greater than or equal to the dimensions of all substrates above it in the stack. That is, the topmost substrate in the substrate stack can have the smallest dimensions in both the x and y directions of all substrates in the stack. The dimensions of each other substrate in the substrate stack in the x and y directions can be greater than or equal to the dimensions of the substrate directly above it. The substrate stack can have a stepped pyramid appearance, with each step corresponding to an exposed portion of the main surface of the substrate in the stack. The substrate stack can be a stepped substrate with continuously decreasing cross-sectional areas.

[0137] Examples include generating a height map above the upper surface of a substrate stack using an optical height sensor. Many known optical height sensors can be used. These measure the distance to the surface in the z-direction based on emitted and reflected light. The light beam can be a laser beam. The height map shows the z-position of the exposed surface of the upper master surface of each substrate in the substrate stack. Examples include using the variation in z-position provided by the optical height map to determine the relative Rx, Ry, and z-positions of the substrates in the substrate stack.

[0138] The embodiments also include obtaining an optical height map of the substrate stack on the PCB and using the optical height map to determine the relative Rx, Ry, and z positions of the PCB and the substrate stack.

[0139] The embodiments include many modifications and variations of the above-described techniques.

[0140] exist Figure 4 In this embodiment, a light spot is generated by illuminating the substrate stack with light from a light source 418 located below the substrate stack. The embodiment also includes generating a light spot by illuminating the substrate stack with light from a light source 418 located above the substrate stack.

[0141] The multi-beam charged particle device can be a component of an inspection (or metrological inspection) tool or part of an electron beam lithography tool. The multi-beam charged particle device according to embodiments can be used in many different applications, which typically include electron microscopy, not just SEM and lithography.

[0142] The embodiments include a multi-beam inspection and / or measurement tool that includes a beam manipulator device manufactured according to the technology of the embodiments. The beam manipulator device 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.

[0143] The embodiments also include a multi-beam lithography tool, which includes the aforementioned beam manipulator device.

[0144] In particular, the multi-beam charged particle device may include the aforementioned beam manipulator device and the reference mentioned above. Figures 1 to 3 Any component of the device described.

[0145] Multi-beam charged particle devices may include a single charged particle source, such as Figures 1 to 3 As shown. Alternatively, a multi-beam charged particle device may include multiple charged particle sources. There may be separate columns for each source and manipulator devices according to embodiments provided in each column. Alternatively, a multi-beam charged particle device may include multiple charged particle sources and only a single column.

[0146] Throughout this embodiment, the z-direction is described, and this can be the charged particle optical axis. This axis describes the path of the charged particles through and from the irradiation device. Multiple sub-beams can all be output 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.

[0147] A particularly preferred application of the embodiments is the fabrication and testing of substrate stacks and PCBs used as beam manipulators in charged particle devices. However, the techniques of the embodiments can be more generally applied to the fabrication and testing of any substrate stacks and PCBs for any application. The embodiments allow for determining the alignment of substrates in a substrate stack. The embodiments can also be used to determine the relative alignment of a PCB and any components positioned on the PCB.

[0148] The embodiments include the following statements.

[0149] According to a first aspect of the invention, a substrate stack comprising a plurality of substrates is provided, wherein: each substrate in the substrate stack includes at least one alignment opening group; the at least one alignment opening group in each substrate is aligned such that a light beam passes through a corresponding alignment opening in each substrate; and each substrate includes at least one alignment opening having a smaller diameter than the corresponding alignment openings in the other substrates.

[0150] Preferably, each substrate in the substrate stack includes a plurality of alignment opening groups; and each alignment opening group of each substrate in the substrate stack is configured such that for each substrate in the substrate stack, there is at least one beam path through the alignment opening group, the at least one beam path indicating the position of the one substrate relative to the other substrates.

[0151] Preferably, the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising substantially straight lines.

[0152] Preferably, the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising multiple substantially straight lines.

[0153] Preferably, the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising two substantially straight lines that intersect each other substantially orthogonally.

[0154] Preferably, the substrate stack includes a beam manipulator array; and each beam manipulator in the array is configured to manipulate a sub-beam of multiple charged particles.

[0155] Preferably, the array of beam manipulators is an N×M array; N is between 2 and 20 (such as 5); and M is between 2 and 20 (such as 5).

[0156] Preferably, each substrate includes at least a first alignment opening group and a second alignment opening group; each alignment opening group on the substrate is located on a portion of the substrate different from the beam manipulator array; and the beam manipulator array is arranged between the first alignment opening group and the second alignment opening group.

[0157] Preferably, the first alignment opening group and the second alignment opening group of each substrate are located at opposite ends of the main surface of the substrate.

[0158] According to a second aspect of the invention, a method is provided for determining the alignment of substrates in a substrate stack comprising a plurality of substrates, the method comprising: determining the positions of a plurality of light beams having passed through corresponding plurality of alignment openings defined in each substrate of the substrate stack; and determining relative x, y, and Rz alignments of at least two substrates in the substrate stack based on the determined positions; wherein: for each light beam path through the substrate stack, an alignment opening of one substrate in the light beam path has a smaller diameter than all or more other alignment openings of the corresponding one or more other substrates in the light beam path; and for each of at least two of the plurality of light beam paths, a different substrate in the light beam path has an alignment opening having a smaller diameter than all or more other alignment openings of the corresponding one or more other substrates in the light beam path, such that: for each of the at least two substrates in the substrate stack, there exists one or more light beam paths whose positions indicate the position of only said one substrate.

[0159] Preferably, the alignment aperture diameter in all substrates is configured such that for each substrate, the position of one or more beam paths depends only on that one substrate.

[0160] Preferably, each substrate in the substrate stack has a substantially planar structure; and the substrates in the substrate stack are stacked in a direction substantially orthogonal to the planar structure.

[0161] Preferably, each substrate in the substrate stack includes a plurality of alignment opening groups; and each alignment opening group of each substrate in the substrate stack is configured such that for each substrate in the substrate stack, there is at least one beam path through the alignment opening group, the at least one beam path indicating the position of the one substrate relative to the other substrates.

[0162] Preferably, the alignment openings in each alignment opening group are configured substantially the same.

[0163] Preferably, the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising substantially straight lines.

[0164] Preferably, the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising multiple substantially straight lines.

[0165] Preferably, the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising two substantially straight lines that intersect each other substantially orthogonally.

[0166] Preferably, the substrate stack includes a beam manipulator array; and each beam manipulator in the array is configured to manipulate a sub-beam of multiple charged particles.

[0167] Preferably, one or more substrates include at least a portion of one or more beam manipulators in a beam manipulator array.

[0168] Preferably, the array of beam manipulators is an N×M array; N is between 2 and 20 (such as 5); and M is between 2 and 20 (such as 5).

[0169] Preferably, each substrate includes at least a first alignment opening group and a second alignment opening group; each alignment opening group on the substrate is located on a portion of the substrate different from the beam manipulator array; and the beam manipulator array is disposed between the first alignment opening group and the second alignment opening group.

[0170] Preferably, the first alignment opening and the second alignment opening of each substrate are located at opposite ends of the main surface of the substrate.

[0171] Preferably, the arrangement of the alignment openings in the first alignment opening group is mirror-symmetrical to the arrangement of the alignment openings in the second alignment opening group.

[0172] Preferably, the method further includes: aligning openings on a substrate stack that irradiates the substrates, such that multiple light beams travel through the substrate stack; obtaining data indicating the position of the light beams; and determining the relative alignment of the substrates in the substrate stack based on the data indicating the position of the light beams.

[0173] Preferably, the method further includes generating one or more images indicating the relative positions of multiple beams based on data indicating the position of the beams.

[0174] Preferably, the data indicating the beam position is obtained by a photodetector, and the method further includes processing the data indicating the beam position to compensate for any tilt between the substrate stack and the optical axis of the photodetector.

[0175] Preferably, the method further includes determining whether the substrate alignment within the substrate stack meets performance specifications based on the determined x, y, and Rz alignment of the substrate.

[0176] According to a third aspect of the invention, a computing system is provided, which is configured to determine the alignment of substrates in a substrate stack by performing the method according to the second aspect.

[0177] According to a fourth aspect of the invention, a tool is provided for obtaining data indicating the position of a light beam, the tool comprising: a stack holder configured to hold a substrate stack according to a first aspect; an irradiator configured to irradiate at least a portion of the surface of the substrate stack; and a photodetector configured to generate data indicating the position of the light beam based on a plurality of light beams that have passed through the substrate stack.

[0178] According to a fifth aspect of the invention, a system is provided that includes the tool according to the fourth aspect and the computing system according to the third aspect.

[0179] According to a sixth aspect of the invention, a method is provided for determining the alignment of substrates in a substrate stack having at least two substrates, wherein each substrate has a plurality of alignment openings aligned with corresponding alignment openings in other substrates of the substrate stack, such that a through-path exists through the substrate stack associated with each alignment opening in each substrate, the method comprising: determining the relative positions of a plurality of light beams, each light beam having passed through the substrate stack along an optical path via a corresponding through-path; and determining relative x, y, and Rz alignments of the substrates in the substrate stack based on the determined positions; wherein: the alignment opening of one of the substrates defining the through-path for the corresponding optical path through the through-path has a smaller diameter than the other alignment openings defining the through-path; and for each optical path, the diameter of the different substrates in the substrate stack is smaller than the diameter of the other alignment openings defining the corresponding through-path in the substrate stack.

[0180] Preferably, the optical paths are configured such that: each optical path indicates the position of one substrate in the substrate stack relative to another substrate in the substrate stack, and / or the relative position of the optical paths indicates the x, y, and Rz alignment of the substrates in the substrate stack.

[0181] According to a seventh aspect of the invention, a substrate stack including a substrate of a beam manipulator is provided, the substrate stack having at least two substrates, wherein each substrate has a plurality of alignment openings aligned with corresponding alignment openings in other substrates of the substrate stack, such that a through-channel is provided through the substrate stack associated with each alignment opening in each substrate, wherein each of the plurality of through-channels is for the passage of a light beam, and the light beam is adapted to determine the relative x, y, and Rz alignment of the substrates in the substrate stack; wherein: the alignment opening of one of the substrates defines a through-channel for a corresponding optical path through the through-channel, having a smaller diameter than the other alignment openings defining the through-channel; and the different substrates in the substrate stack have alignment openings having a smaller diameter than the other alignment openings defining the corresponding through-channels in the substrate stack.

[0182] Preferably, each through channel is a channel for different optical paths; each optical path has an indication of the position of one substrate in the substrate stack relative to other substrates in the substrate stack; and / or the relative position of the optical paths indicates the x, y, and Rz alignment of the substrates in the substrate stack.

[0183] According to an eighth aspect of the invention, there is provided an arrangement of printed circuit board (PCB) substrate stacks disposed on the PCB, wherein: an opening is defined in the PCB, the opening being configured to align with a through channel in the substrate stack for interaction with a stacked light source; and the surface of the PCB includes a plurality of alignment structures configured to interact with the PCB light source.

[0184] Preferably, the PCB and substrate stack are configured such that the interaction between the stack light source and the through channels in the substrate stack and the corresponding openings in the PCB, as well as the interaction between the PCB light source and the multiple alignment structures, can determine the relative x, y, and Rz alignment of the substrate stack and the PCB.

[0185] According to a ninth aspect of the invention, a printed circuit board (PCB) and a substrate stack are provided, wherein a plurality of through channels for beam path openings are defined in the substrate stack, the substrate stack being disposed on the PCB, wherein a plurality of alignment structures are disposed on the surface of the PCB and are configured to interact with a light source to enable alignment of the PCB to be determined.

[0186] According to a tenth aspect of the invention, a method is provided for determining the relative alignment of a substrate stack with a printed circuit board (PCB), wherein the substrate stack is disposed on the PCB, the method comprising: determining the positions of a first plurality of light beams having passed through a plurality of openings in the substrate stack and at least one opening in the PCB; determining the positions of a second plurality of light beams depending on a plurality of PCB alignment structures; and determining the relative x, y, and Rz alignment of the substrate stack and the PCB based on the determined positions of the first and second plurality of light beams.

[0187] Preferably, the PCB alignment structure includes markings on the PCB configured to reflect at least some of the second plurality of light beams; wherein the position of the second plurality of light beams is determined after the second plurality of light beams have been reflected away from the corresponding plurality of markings on the PCB.

[0188] Preferably, the PCB alignment structure includes one or more alignment openings in the PCB; wherein the position of the second plurality of beams is determined after the second plurality of beams have passed through the corresponding plurality of alignment openings in the PCB.

[0189] Preferably, none of the second plurality of beams passes through the substrate stack.

[0190] Preferably, the method further includes: illuminating the PCB and the substrate stack; obtaining data indicating the positions of the first and second plurality of beams; and determining the relative x, y, and Rz alignment of the substrate stack and the PCB based on the obtained data indicating the positions of the first and second plurality of beams.

[0191] Preferably, one or more images are generated by a photodetector, and the method further includes processing data indicating the positions of the first and second plurality of beams in order to compensate for any tilt between the substrate stack and the optical axis of the photodetector.

[0192] Preferably, the method further includes determining whether the relative alignment of the PCB and substrate stack meets performance specifications based on the determined x, y, and Rz alignments.

[0193] According to an eleventh aspect of the invention, a computing system is provided, which is configured to determine the alignment of a PCB and substrate stack by performing the method according to the tenth aspect.

[0194] 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 examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the appended claims and terms.

[0195] The following terms are provided; Term 1: A substrate stack comprising a plurality of substrates, wherein: each substrate in the substrate stack includes at least one alignment opening group; the at least one alignment opening group in each substrate is aligned to allow a light beam to pass through a corresponding alignment opening in each substrate; and each substrate includes at least one alignment opening having a smaller diameter than the corresponding alignment openings in the other substrates.

[0196] Clause 2: The substrate stack according to Clause 1, wherein each substrate in the substrate stack includes a plurality of alignment opening groups; and each alignment opening group of each substrate in the substrate stack is configured such that for each of the substrates in the substrate stack, there is at least one beam path through the alignment opening group, the at least one beam path indicating the position of the one substrate relative to the other substrates.

[0197] Clause 3: A substrate stack according to any one of Clauses 1 or 2, wherein the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising substantially straight lines.

[0198] Clause 4: A substrate stack according to any one of Clauses 1 or 2, wherein the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising a plurality of substantially straight lines.

[0199] Clause 5: A substrate stack according to Clause 1 or 2, wherein the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising two substantially straight lines that intersect each other substantially orthogonally.

[0200] Clause 6: A substrate stack according to any one of the preceding clauses, wherein the substrate stack includes an array of beam manipulators; and each beam manipulator in the array is configured to manipulate a sub-beam of multiple charged particles.

[0201] Clause 7: The substrate stack according to Clause 6, wherein the beam manipulator array is an N×M array; N is between 2 and 20, such as 5; and M is between 2 and 20, such as 5.

[0202] Clause 8: A substrate stack according to any of the preceding clauses, wherein: each substrate includes at least a first alignment opening group and a second alignment opening group; each alignment opening on the substrate is on a portion of the substrate that is different from the beam manipulator array; and the beam manipulator array is arranged between the first alignment opening group and the second alignment opening group.

[0203] Clause 9: The substrate stack according to Clause 8, wherein the first alignment opening group and the second alignment opening group of each substrate are located at opposite ends of the main surface of the substrate.

[0204] Clause 10: A method for determining the alignment of substrates in a substrate stack comprising a plurality of substrates, the method comprising: determining the positions of a plurality of light beams having passed through a plurality of alignment openings defined in each substrate of the substrate stack; and determining the relative x, y, and Rz alignment of at least two substrates in the substrate stack based on the determined positions; wherein: for each light beam path through the substrate stack, the alignment opening of one of the substrates in the light beam path has a diameter smaller than all or more other alignment openings of the corresponding one or more other substrates in the light beam path; and for each of the at least two light beam paths, a different substrate in the substrates in the light beam path has an alignment opening having a diameter smaller than all or more other alignment openings of the corresponding one or more other substrates in the light beam path, such that: for each of the at least two substrates in the substrate stack, there exists one or more light beam paths whose positions indicate the position of only the one substrate.

[0205] Clause 11: The method according to Clause 10, wherein the alignment aperture diameter in all said substrates is configured such that for each of said substrates, the position of one or more beam paths depends only on said one substrate.

[0206] Clause 12: The method according to Clause 10 or 11, wherein each substrate in the substrate stack has a substantially planar structure; and the substrates in the substrate stack are stacked in a direction substantially perpendicular to the planar structure.

[0207] Clause 13: The method according to any one of Clauses 10 to 12, wherein each substrate in the substrate stack includes a plurality of alignment opening groups; and each alignment opening group of each substrate in the substrate stack is configured such that for each of the substrates in the substrate stack, there exists at least one beam path through the alignment opening group, the at least one beam path indicating the position of the one substrate relative to the other substrates.

[0208] Clause 14: The method according to any one of Clause 13, wherein the configuration of the alignment openings in each alignment opening group is substantially the same.

[0209] Clause 15: The method according to any one of Clauses 13 or 14, wherein the alignment openings in each alignment opening group are configured such that the alignment openings form a pattern comprising substantially straight lines.

[0210] Clause 16: The method according to any one of Clauses 13 or 14, wherein the alignment opening in each alignment opening group is configured such that the alignment opening forms a pattern comprising a plurality of substantially straight lines.

[0211] Clause 17: The method according to any one of Clauses 13 or 14, wherein the alignment opening in each alignment opening group is configured such that the alignment opening forms a pattern comprising two substantially straight lines intersecting each other substantially orthogonally.

[0212] Clause 18: The method according to any one of Clauses 10 to 17, wherein the substrate stack comprises a beam manipulator array; and each beam manipulator in the array is configured to manipulate a sub-beam of multiple charged particles.

[0213] Clause 19: The method according to Clause 18, wherein one or more of the substrates comprises at least a portion of one or more beam manipulators in the beam manipulator array.

[0214] Clause 20: The method according to Clause 18 or 19, wherein the beam manipulator array is an N×M array; N is between 2 and 20, such as 5; and M is between 2 and 20, such as 5.

[0215] Clause 21: The method according to any one of Clauses 13 to 20, wherein: each substrate includes at least a first alignment opening group and a second alignment opening group; each alignment opening group on the substrate is on a portion of the substrate that is different from the beam manipulator array; and the beam manipulator array is arranged between the first alignment opening group and the second alignment opening group.

[0216] Clause 22: The method according to Clause 21, wherein the first alignment opening and the second alignment opening of each substrate are located at opposite ends of the main surface of the substrate.

[0217] Clause 23: The method according to Clause 21 or 22, wherein the arrangement of the alignment openings in the first alignment opening group is mirror-symmetric to the arrangement of the alignment openings in the second alignment opening group.

[0218] Clause 24: The method according to any one of Clauses 10 to 23 further comprises: illuminating the alignment opening on the substrate stack such that a plurality of light beams pass through the substrate stack; obtaining data indicating the position of the light beams; and determining the relative alignment of the substrates in the substrate stack based on the data indicating the position of the light beams.

[0219] Clause 25: The method according to Clause 24 further includes generating one or more images indicating the relative positions of the plurality of beams based on the data indicating the position of the beams.

[0220] Clause 26: The method according to Clause 24 or 25, wherein the data indicating the position of the beam is obtained by a photodetector, and the method further includes processing the data indicating the position of the beam to compensate for any tilt between the substrate stack and the optical axis of the photodetector.

[0221] Clause 27: The method according to any one of Clauses 10 to 26 further includes determining whether the alignment of the substrates within the substrate stack meets the performance specifications based on the determined x, y, and Rz alignment of the substrates.

[0222] Clause 28: A computing system configured to determine the alignment of substrates in a substrate stack by performing a method according to any one of Clauses 10 to 27.

[0223] Clause 29: A tool for obtaining data indicating the position of a light beam, the tool comprising: a stack holder configured to hold a substrate stack according to any one of Clauses 1 to 9; an irradiator configured to irradiate at least a portion of the surface of the substrate stack; and a photodetector configured to generate data indicating the position of the light beam based on a plurality of light beams that have passed through the substrate stack.

[0224] Clause 30: A system comprising the tools described in Clause 29 and the computing system described in Clause 28.

[0225] Clause 31: A method for determining the alignment of substrates in a substrate stack having at least two substrates, wherein each of the substrates has a plurality of alignment openings aligned with corresponding alignment openings in other substrates of the substrate stack such that a through-path exists through the substrate stack associated with each alignment opening in each substrate, the method comprising: determining the relative positions of a plurality of light beams, each light beam having passed through the substrate stack along an optical path via a corresponding through-path; and determining the relative x, y, and Rz alignment of the substrates in the substrate stack based on the determined positions; wherein: the alignment opening of one of the substrates defining the through-path for the corresponding optical path through the through-path has a smaller diameter than the other alignment openings defining the through-path; and for each optical path, the diameter of the different substrates in the substrate stack is smaller than the diameter of the other alignment openings defining the corresponding through-path in the substrate stack.

[0226] Clause 32: The method according to Clause 31, wherein the optical path is configured such that: each optical path has an indication of the position of one substrate in the substrate stack relative to another substrate in the substrate stack, and / or the relative position of the optical path indicates the x, y, and Rz alignment of the substrates in the substrate stack.

[0227] Clause 33: A substrate stack including a substrate of a beam manipulator, the substrate stack having at least two substrates, wherein each substrate has a plurality of alignment openings aligned with corresponding alignment openings in other substrates of the substrate stack such that a through-channel is present through the substrate stack associated with each alignment opening in each substrate, wherein each of the plurality of through-channels is used for the passage of a light beam, and the light beam is adapted to determine the relative x, y, and Rz alignment of the substrates in the substrate stack; wherein: the alignment opening of the through-channel of one of the substrates defining a corresponding optical path through the through-channel has a smaller diameter than the other alignment openings defining the through-channel; and the different substrates in the substrate stack have alignment openings having a smaller diameter than the other alignment openings defining the corresponding through-channels in the substrate stack.

[0228] Clause 34: In a substrate stack according to Clause 33, each through channel is a channel for a different optical path; each optical path has an indication of the position of one substrate in the substrate stack relative to the other substrates in the substrate stack; and / or the relative position of the optical path indicates the x, y, and Rz alignment of the substrates in the substrate stack.

[0229] Clause 35: A combination of a printed circuit board (PCB) and a substrate stack according to Clause 33 or 34, the substrate stack being disposed on the PCB, wherein an opening is defined in the PCB, the opening being configured to align with a through-channel in the substrate stack for interaction with a stacked light source; the surface of the PCB includes a plurality of alignment structures configured to interact with the PCB light source.

[0230] Clause 36: The combination according to Clause 35, wherein the PCB and the substrate stack are configured such that the interaction of the stacked light source with the through-channel in the substrate stack and the corresponding opening in the PCB, and the interaction of the PCB light source with the plurality of alignment structures, enables the relative x, y, and Rz alignment of the substrate stack and the PCB to be determined.

[0231] Clause 37: A combination of a printed circuit board, a PCB, and a substrate stack, wherein a plurality of through channels are defined for beam path openings, the substrate stack being disposed on the PCB, wherein a plurality of alignment structures are disposed on the surface of the PCB, the alignment structures being configured to interact with a light source to enable the determination of the alignment of the PCB.

[0232] Clause 38: A method for determining the relative alignment of a substrate stack and a printed circuit board (PCB), wherein the substrate stack is disposed on the PCB, the method comprising: determining the positions of a first plurality of light beams having passed through a plurality of corresponding openings in the substrate stack and at least one opening in the PCB; determining the positions of a second plurality of light beams depending on a plurality of PCB alignment structures; and determining the relative x, y, and Rz alignment of the substrate stack and the PCB based on the determined positions of the first plurality of light beams and the second plurality of light beams.

[0233] Clause 39: The method according to Clause 38, wherein the PCB alignment structure includes markings on the PCB configured to reflect at least some of the second plurality of light beams; wherein the position of the second plurality of light beams is determined after the second plurality of light beams have been reflected away from the corresponding plurality of markings on the PCB.

[0234] Clause 40: The method according to Clause 39, wherein the PCB alignment structure includes one or more alignment openings in the PCB; wherein the position of the second plurality of beams is determined after the second plurality of beams have passed through the respective plurality of alignment openings in the PCB.

[0235] Clause 41: The method according to any one of Clauses 38 to 40, wherein none of the second plurality of beams passes through the substrate stack.

[0236] Clause 42: The method according to any one of Clauses 38 to 41 further comprises: irradiating the PCB and the substrate stack; obtaining data indicating the positions of the first plurality of light beams and the second plurality of light beams; and determining the relative x, y, and Rz alignment of the substrate stack and the PCB based on the obtained data indicating the positions of the first plurality of light beams and the second plurality of light beams.

[0237] Clause 43: The method according to any one of Clauses 38 to 41, wherein the one or more images are generated by a photodetector, and the method further comprises processing data indicating the positions of the first plurality of light beams and the second plurality of light beams in order to compensate for any tilt between the substrate stack and the optical axis of the photodetector.

[0238] Clause 44: The method according to any one of Clauses 38 to 41 further includes determining whether the relative alignment of the PCB and substrate stack meets the performance specifications based on the determined x, y, and Rz alignment.

[0239] Clause 45: A computing system configured to determine the alignment of a PCB and substrate stack by performing a method according to any one of Clauses 38 to 44.

[0240] The above description is intended to illustrate and not limit. Therefore, it will be apparent to those skilled in the art that modifications as described can be made without departing from the scope of the claims set forth below and the terms provided above.

Claims

1. A substrate stack comprising multiple substrates, wherein: Each substrate in the substrate stack includes at least one group of alignment openings; The at least one alignment opening group in each substrate is aligned to allow the light beam to pass through the corresponding alignment opening in each substrate; For each beam path through the stacked substrates, the alignment opening of one substrate in the beam path has a smaller diameter than all or more other alignment openings of the corresponding one or more other substrates in the beam path; and For each of at least two beam paths, one of the different substrates on the beam path has an alignment opening with a diameter smaller than all or more other alignment openings of the corresponding one or more other substrates on the beam path, such that for each of the at least two substrates in the substrate stack, there exists one or more beam paths whose positions indicate the position of only said one substrate.

2. The substrate stack of claim 1, wherein each substrate in the substrate stack includes a plurality of alignment opening groups; and Each alignment opening group of each substrate in the substrate stack is configured such that for each of the substrates in the substrate stack, there is at least one beam path through the alignment opening group, the at least one beam path indicating the position of the one substrate relative to the other substrates.

3. The substrate stack according to any one of claims 1 or 2, wherein the alignment opening in each alignment opening group is configured such that the alignment opening forms a pattern comprising: straight lines; multiple straight lines or two straight lines intersecting each other orthogonally.

4. The substrate stack according to any one of claims 1 or 2, wherein the substrate stack comprises a beam manipulator array; and Each beam manipulator in the array is configured to manipulate a sub-beam of multiple charged particles.

5. The substrate stack of claim 4, wherein the beam manipulator array is an N×M array; N is between 2 and 20; and M is between 2 and 20.

6. The substrate stack according to claim 4, wherein: Each substrate includes at least a first alignment opening group and a second alignment opening group; Each alignment opening group on the substrate is located on a portion of the substrate that is different from the beam manipulator array; as well as The beam manipulator array is arranged between the first alignment opening group and the second alignment opening group.

7. The substrate stack of claim 6, wherein the first alignment opening group and the second alignment opening group of each substrate are located at opposite ends of the main surface of the substrate.

8. A method for determining the alignment of substrates in a substrate stack comprising a plurality of substrates, the method comprising: The positions of multiple light beams are determined, the multiple light beams having passed through corresponding multiple alignment openings defined in each substrate of the substrate stack; as well as The alignment of at least two substrates in the substrate stack relative to x, y, and Rz is determined based on the determined positions; in: For each beam path through the substrate stack, the alignment opening of one of the substrates in the beam path has a smaller diameter than all or more other alignment openings of the corresponding one or more other substrates in the beam path; as well as For each of at least two of a plurality of beam paths, a different substrate in the substrate on the beam path has an alignment opening having a diameter smaller than all or more other alignment openings of the corresponding one or more other substrates on the beam path, such that for each of the at least two substrates in the substrate stack, there exists one or more beam paths whose positions indicate the position of only the one substrate.

9. The method of claim 8, wherein the alignment aperture diameter in all of the substrates is configured such that, for each of the substrates, the position of one or more beam paths depends only on that one substrate.

10. The method of claim 8 or 9, wherein each substrate in the substrate stack has a planar structure; and the substrates in the substrate stack are stacked in a direction orthogonal to the planar structure.

11. The method of claim 8 or 9, wherein each substrate in the substrate stack includes a plurality of alignment opening groups; and each alignment opening group of each substrate in the substrate stack is configured such that for each of the substrates in the substrate stack, there exists at least one beam path through the alignment opening group, the at least one beam path indicating the position of the one substrate relative to the other substrates.

12. The method of claim 11, wherein the configuration of the alignment openings in each alignment opening group is identical.

13. The method of claim 11, wherein the alignment opening in each alignment opening group is configured such that the alignment opening forms a pattern comprising: straight lines; multiple straight lines; or two straight lines that intersect each other orthogonally.

14. The method of claim 8 or 9, wherein the substrate stack comprises a beam manipulator array; and each beam manipulator in the array is configured to manipulate a sub-beam of multiple charged particles.

15. The method of claim 14, wherein one or more of the substrates comprise at least a portion of one or more beam manipulators in the beam manipulator array.

16. The method of claim 14, wherein the beam manipulator array is an N×M array; N is between 2 and 20; and M is between 2 and 20.

17. The method of claim 14, wherein: Each substrate includes at least a first alignment opening group and a second alignment opening group; Each alignment opening group on the substrate is located on a portion of the substrate that is different from the beam manipulator array; as well as The beam manipulator array is arranged between the first alignment opening group and the second alignment opening group.

18. The method of claim 17, wherein the first alignment opening and the second alignment opening of each substrate are located at opposite ends of the main surface of the substrate.

19. The method of claim 17, wherein the arrangement of the alignment openings in the first alignment opening group is mirror-symmetric to the arrangement of the alignment openings in the second alignment opening group.

20. The method according to claim 8 or 9, further comprising: The alignment opening on the substrate stack that irradiates the substrate allows multiple light beams to pass through the substrate stack; Obtain data indicating the position of the beam; The relative alignment of the substrates in the substrate stack is determined based on the data indicating the position of the light beam.

21. The method of claim 20, further comprising: One or more images indicating the relative positions of the plurality of beams are generated based on the data indicating the position of the beams.

22. The method of claim 20, wherein the data indicating the position of the beam is obtained by a photodetector, and the method further comprises: The data indicating the position of the light beam is processed to compensate for any tilt between the substrate stack and the optical axis of the photodetector.

23. The method according to claim 8 or 9, further comprising: The alignment of the substrates within the substrate stack is determined based on the determined alignment of the substrates relative to x, y, and Rz to determine whether the alignment meets the performance specifications.

24. A computing system configured to determine the alignment of substrates in a substrate stack by performing the method according to any one of claims 8 to 23.

25. A tool for obtaining data indicating the position of a light beam, the tool comprising: A stack holder, configured to hold a substrate stack according to any one of claims 1 to 6; An irradiator is configured to irradiate at least a portion of the surface of the substrate stack; as well as A photodetector is configured to generate data indicating the position of a beam based on a plurality of beams that have passed through the substrate stack.

26. A system comprising the tool of claim 25 and the computing system of claim 24.

27. A method for determining alignment of substrates in a substrate stack having at least two substrates, wherein each of the substrates has a plurality of alignment openings, the plurality of alignment openings being aligned with corresponding alignment openings in other substrates of the substrate stack such that a through-channel exists through the substrate stack and associated with each alignment opening in each substrate, the method comprising: The relative positions of multiple light beams are determined, each beam having passed through the substrate stack along the optical path via a corresponding through channel; as well as The alignment of the substrates in the substrate stack relative to x, y, and Rz is determined based on the determined positions; in: The alignment opening of the through-channel in one of the substrates, which defines a corresponding optical path for passing through the through-channel, has a smaller diameter than the other alignment openings defining the through-channel; and For each optical path, the diameter of the different substrates in the substrate stack has a smaller diameter than the other alignment openings that define the corresponding through-channel in the substrate stack.

28. The method of claim 27, wherein the optical paths are configured such that: each optical path has an indication of the position of one substrate in the substrate stack relative to the other substrates in the substrate stack, and / or The relative position of the optical path indicates the alignment of the substrates in the substrate stack relative to x, y, and Rz.

29. A substrate stack including a substrate of a beam manipulator, the substrate stack having at least two substrates, wherein each substrate has a plurality of alignment openings aligned with corresponding alignment openings in other substrates of the substrate stack, such that a through-channel exists through the substrate stack and associated with each alignment opening in each substrate, wherein each of the plurality of through-channels is a channel for a light beam, and the light beam is adapted to determine the alignment of the substrates in the substrate stack relative to x, y, and Rz; wherein: The alignment opening of the through channel in one of the substrates, which defines a corresponding optical path for passing through the through channel, has a smaller diameter than the other alignment openings defining the through channel; and One of the different substrates in the substrate stack has an alignment opening with a smaller diameter than other alignment openings that define the corresponding through-channel in the substrate stack.

30. The substrate stack of the substrate according to claim 29, wherein each through-channel is a channel for a different optical path.

31. The substrate stack of claim 30, wherein each optical path has an indication of the position of one substrate in the substrate stack relative to the other substrates in the substrate stack.

32. The substrate stack of the substrate according to claim 30 or 31, wherein the relative position of the optical path indicates the alignment of the substrates in the substrate stack relative to x, y, and Rz.

33. A combination of a printed circuit board (PCB) and a substrate stack according to any one of claims 29 to 32, wherein the substrate stack is disposed on the PCB, wherein: An opening is defined in the PCB, the opening being configured to align with the through-channel in the substrate stack for interaction with the stacked light source; and The surface of the PCB includes multiple alignment structures configured to interact with a PCB light source.

34. The combination of claim 33, wherein the PCB and the substrate stack are configured such that the interaction of the stacked light source with the through-channel in the substrate stack and the corresponding opening in the PCB, and the interaction of the PCB light source with the plurality of alignment structures, enables the alignment of the substrate stack and the PCB with respect to x, y, and Rz to be determined.

35. A combination of a printed circuit board, a PCB, and a substrate stack, wherein a plurality of through channels are defined for beam path openings, the substrate stack being disposed on the PCB, wherein a plurality of alignment structures are in the surface of the PCB, the alignment structures being configured to interact with a light source to enable determination of the alignment of the PCB, wherein the substrate stack is a substrate stack according to any one of claims 1 to 7.

36. A method for determining the relative alignment of a substrate stack and a printed circuit board (PCB), wherein the substrate stack is a substrate stack according to any one of claims 1 to 7, wherein the substrate stack is disposed on the PCB, the method comprising: Determine the position of a first plurality of beams, which have passed through corresponding plurality of openings through the substrate stack and at least one opening in the PCB; Determine the position of the second multiple beams, which depends on the multiple PCB alignment structures; as well as The alignment of the substrate stack and the PCB relative to x, y, and Rz is determined based on the positions of the first plurality of beams and the second plurality of beams.

37. The method of claim 36, wherein the PCB alignment structure includes markings on the PCB configured to reflect at least some of the second plurality of light beams; wherein the position of the second plurality of light beams is determined after the second plurality of light beams have been reflected away from the corresponding plurality of markings on the PCB.

38. The method of claim 37, wherein the PCB alignment structure includes one or more alignment openings in the PCB; wherein the position of the second plurality of beams is determined after the second plurality of beams have passed through the respective plurality of alignment openings in the PCB.

39. The method according to any one of claims 36 to 38, wherein none of the second plurality of beams passes through the substrate stack.

40. The method according to any one of claims 36 to 38, further comprising: Irradiate the stacked PCB and substrate; Obtain data indicating the positions of the first plurality of beams and the second plurality of beams; as well as The alignment of the substrate stack and the PCB relative to x, y, and Rz is determined based on the obtained data indicating the positions of the first plurality of beams and the second plurality of beams.

41. The method according to any one of claims 36 to 38, wherein the one or more images are generated by a photodetector, and the method further comprises: The data indicating the positions of the first plurality of beams and the second plurality of beams are processed in order to compensate for any tilt between the substrate stack and the optical axis of the photodetector.

42. The method according to any one of claims 36 to 38, further comprising: The relative alignment of the PCB and substrate stack is determined based on the determined relative x, y, and Rz alignments to determine whether the relative alignment meets the performance specifications.

43. A computing system configured to determine the alignment of a PCB and substrate stack by performing the method according to any one of claims 36 to 42.

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