BEAM MANIPULATOR IN CHARGED PARTICLE-BEAM EXPOSURE APPARATUS

An improved electron beam manipulator for manipulating an electron beam in an electron projection system and a method for manufacturing thereof are disclosed. The electron beam manipulator comprises a body having a first surface and a second surface opposing to the first surface and an interconnecting surface extending between the first surface and the second surface and forming an aperture through the body. The body comprises an electrode forming at least part of the interconnecting surface between the first surface and the second surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of EP application 20161464.1, which was filed on 6 Mar. 2020 and which is incorporated herein its entirety by reference.

FIELD

The embodiments provided herein generally relate to a charged particle beam illumination apparatus, and more particularly to a charged particle beam manipulator in a charged particle-beam illumination apparatus.

BACKGROUND

When manufacturing semiconductor integrated circuit (IC) chips, undesired pattern defects, as a consequence of, for example, optical effects and incidental particles, inevitably occur on a substrate (i.e., wafer) or a mask during the fabrication processes, thereby reducing the yield. Monitoring the extent of the undesired pattern defects is therefore an important process in the manufacture of IC chips. More generally, the inspection and/or measurement of a surface of a substrate, or other object/material, is an import process during and/or after its manufacture.

Pattern inspection tools with a charged particle beam have been used to inspect objects, for example to detect pattern defects. These tools typically use electron microscopy techniques, such as a scanning electron microscope (SEM). In a SEM, a primary electron beam of electrons at a relatively high energy is targeted with a final deceleration step in order to land on a sample at a relatively low landing energy. The beam of electrons is focused as a probing spot on the sample. The interactions between the material structure at the probing spot and the landing electrons from the beam of electrons cause electrons to be emitted from the surface, such as secondary electrons, backscattered electrons, or Auger electrons. The generated secondary electrons may be emitted from the material structure of the sample. By scanning the primary electron beam as the probing spot over the sample surface, secondary electrons can be emitted across the surface of the sample. By collecting these emitted secondary electrons from the sample surface, a pattern inspection tool may obtain an image representing characteristics of the material structure of the surface of the sample.

Another application for a charged particle beam is lithography. The charged particle beam reacts with a resist layer on the surface of a substrate. A desired pattern in the resist can be created by controlling the locations on the resist layer that the charged particle beam is directed towards.

There is a general need to improve the generation of a charged particle beam for use in electron microscopy as well as for other applications, such as lithography.

SUMMARY

The embodiments provided herein disclose a charged particle beam illumination apparatus. The charged particle beam illumination apparatus may be used to generate a multi-beam of charged particles. The charged particle beam illumination apparatus may be comprised within an inspection apparatus or a lithography apparatus.

In some embodiments, an electron beam manipulator for manipulating an electron beam in an electron projection system is provided. The electron beam manipulator comprises a body having a first surface and a second surface opposing to the first surface and an interconnecting surface extending between the first surface and the second surface and forming an aperture through the body. The body comprises an electrode forming at least part of the interconnecting surface between the first surface and the second surface.

In some embodiments, an electron beam manipulator device for manipulating an electron beam in an electron projection system is provided. The electron beam manipulating device comprises a first manipulator and a second manipulator. Each of the first manipulator and the second manipulator comprises a body having a first surface and a second surface opposing to the first surface and an interconnecting surface extending between the first surface and the second surface and forming an aperture through the body. The body comprises an electrode forming at least part of the interconnecting surface between the first surface and the second surface. At least part of the electrode is associated with the aperture and is positioned on the first surface. The first manipulator is positioned upstream of the second manipulator in a direction of the electron beam during operation.

In some embodiments, a method for manufacturing an electron beam manipulator is provided. The method comprises providing a workpiece comprising a substrate having a first surface and a second surface and an electrode layer formed relative to the first surface, the electrode layer having an electrode portion, forming a resist mask having an opening corresponding to a pattern on the workpiece, leaving an unmasked portion of the substrate, etching the unmasked portion of the substrate such that an inner wall is formed through the substrate to extend between the first surface and the second surface, removing the resist mask, and forming a first conductive layer coating the inner wall of the substrate.

In some embodiments, a method for manufacturing an electron beam manipulator is provided. The method comprises providing a workpiece comprising a conductive substrate having a first surface and a second surface, forming an isolation layer extending between the first surface and the second surface and electrically isolating a first substrate portion from a second substrate portion, the first substrate portion being positioned radially inward from the second substrate portion, and etching a part of the first substrate portion such that an inner wall extends through the substrate between the first surface and the second surface, the inner wall providing at least an electrode surface.

In some embodiments, an electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool is provided. The charged particle beam manipulator comprises a substrate having opposing major surfaces and through opening providing an interconnecting surface extending between the major surfaces. At least part of the interconnecting surface is defined by one or more electrodes.

In some embodiments, an electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool is provided. The charged particle beam manipulator comprises a substrate having opposing major surfaces and an electrode. The electrode forms at least part of a surface of an interconnecting-through-hole extending between the major surfaces, the through-hole forming an opening in each of the major surfaces. The electrode forms at least part of one of the two major surfaces surrounding one of the openings.

In some embodiments, an electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool is provided. The charged particle beam manipulator comprises a substrate having opposing major surfaces and a through-passage providing an interconnecting surface extending between the major surfaces. At least part of the interconnecting surface is formed by an electrode configured in use to be held at a potential difference.

In some embodiments, an electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool is provided. The charged particle beam manipulator comprises a substrate body having opposing major surfaces and a through-passage having an interconnecting surface extending between the major surfaces. At least part of the interconnecting surface is recessed: between adjoining edges of at least one electrode; and into the substrate body deeper than the thickness of the at least one electrode.

DETAILED DESCRIPTION

The enhanced computing power of electronic devices, which reduces the physical size of the devices, can be accomplished by significantly increasing the packing density of circuit components such as transistors, capacitors, diodes, etc. on an IC chip. This has been enabled by increased resolution enabling yet smaller structures to be made. For example, an IC chip of a smart phone, which is the size of a thumbnail, may include over 2 billion transistors, the size of each transistor being less than 1/1000th of a human hair. Thus, it is not surprising that semiconductor IC manufacturing is a complex and time-consuming process, with hundreds of individual steps. Errors in even one step have the potential to dramatically affect the functioning of the final product. Just one “killer defect” can cause device failure. The goal of the manufacturing process is to improve the overall yield of the process. For example, to obtain a 75% yield for a 50-step process (where a step can indicate the number of layers formed on a wafer), each individual step must have a yield greater than 99.4%. If an individual step has a yield of 95%, the overall process yield would be as low as 7%.

One component of improving yield is monitoring the chip making process to ensure that it is producing a sufficient number of functional integrated circuits. One way to monitor the process is to inspect the chip circuit structures at various stages of their formation. Inspection can be carried out using a scanning electron microscope (SEM). An SEM can be used to image these extremely small structures, in effect, taking a “picture” of the structures. The image can be used to determine if the structure was formed properly and also if it was formed in the proper location. If the structure is defective, then the process can be adjusted so the defect is less likely to recur.

While high process yield is desirable in an IC chip manufacturing facility, maintaining a high substrate (i.e. wafer) throughput, defined as the number of substrates processed per hour, is also essential. High process yield and high substrate throughput can be impacted by the presence of a defect. This is especially if operator intervention is required for reviewing the defects. Thus, high throughput detection and identification of micro and nano-scale defects by inspection tools (such as a SEM) is essential for maintaining high yield and low cost).

A SEM comprises a scanning device and a detector apparatus. The scanning device comprises an illumination apparatus that comprises an electron source, for generating primary electrons, and a projection apparatus for scanning 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. The detection apparatus captures the secondary electrons from the sample as the sample is scanned so that the SEM can create an image of the scanned area of the sample. For high throughput inspection, some of the inspection apparatuses use multiple focused beams, i e. a multi-beam, of primary electrons. The component beams of the multi-beam may be referred to as sub-beams or beamlets. A multi-beam can scan different parts of a sample simultaneously. A multi-beam inspection apparatus can therefore inspect a sample at a much higher speed than a single-beam inspection apparatus.

In a multi-beam inspection apparatus, the paths of some of the primary electron beams are displaced away from the central axis, i.e. a mid-point of the primary electron optical axis, of the scanning device. To ensure all the electron beams arrive at the sample surface with substantially the same angle of incidence, sub-beam paths with a greater radial distance from the central axis need to be manipulated to move through a greater angle than the sub-beam paths with paths closer to the central axis. This stronger manipulation may cause aberrations which result in blurry and out-of-focus images of the sample substrate. In particular, for sub-beam paths that are not on the central axis, the aberrations in the sub-beams may increase with the radial displacement from the central axis. Such aberrations may remain associated with the secondary electrons when they are detected. Such aberrations therefore degrade the quality of images that are created during inspection.

The figures are schematic. Relative dimensions of components in drawings are therefore exaggerated for clarity. Within the following description of drawings the same or like reference numbers refer to the same or like components or entities, and only the differences with respect to the individual embodiments are described. While the description and drawings are directed to an electron-optical apparatus, it is appreciated that the embodiments are not used to limit the present disclosure to specific charged particles. References to electrons throughout the present document may therefore be generally considered as references to charged particles, with the charged particles not necessarily being electrons.

Reference is made toFIG.1, which is a schematic diagram illustrating an exemplary charged particle beam inspection apparatus100. The charged particle beam inspection apparatus100ofFIG.1includes a main chamber10, a load lock chamber20, an electron beam tool40, an equipment front end module (EFEM)30and a controller50. The electron beam tool40is located within the main chamber10. While the description and drawings are directed to an electron beam, it is appreciated that the embodiments are not used to limit the present disclosure to specific charged particles.

The EFEM30includes a first loading port30aand a second loading port30b.The EFEM30may include additional loading port(s). The first loading port30aand the second loading port30bmay, for example, receive substrate front opening unified pods (FOUPs) that contain substrates (e.g., semiconductor substrates or substrates made of other material(s)) or samples to be inspected (substrates, wafers, and samples are collectively referred to as “samples” hereafter). One or more robot arms (not shown) in EFEM30transport the samples to the load lock chamber20.

The load lock chamber20is used to remove the gas around a sample. This creates a vacuum that is a local gas pressure lower than the pressure in the surrounding environment. The load lock chamber20may be connected to a load lock vacuum pump system (not shown), which removes gas particles in the load lock chamber20. The operation of the load lock vacuum pump system enables the load lock chamber20to reach a first pressure below the atmospheric pressure. After reaching the first pressure, one or more robot arms (not shown) transport the sample from the load lock chamber20to the main chamber10. The main chamber10is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes gas particles in the main chamber10so that the pressure in around the sample reaches a second pressure lower than the first pressure. After reaching the second pressure, the sample is transported to the electron beam tool by which it may be inspected. An electron beam tool40may comprise a multi-beam electron-optical apparatus.

The controller50is electronically connected to the electron beam tool40. The controller50may be a processor (such as a computer) configured to control the charged particle beam inspection apparatus100. The controller50may also include a processing circuitry configured to execute various signal and image processing functions. While the controller50is shown inFIG.1as being outside of the structure that includes the main chamber10, the load lock chamber20, and the EFEM30, it is appreciated that the controller50may be part of the structure. The controller50may be located in one of the component elements of the charged particle beam inspection apparatus100or it can be distributed over at least two of the component elements. While the present disclosure provides examples of main chamber10housing an electron beam inspection tool, it should be noted that aspects of the disclosure in their broadest sense are not limited to a chamber housing an electron beam inspection tool. Rather, it is appreciated that the foregoing principles may also be applied to other tools and other arrangements of apparatus, that operate under the second pressure.

Reference is now made toFIG.2, which is a schematic diagram illustrating an exemplary electron beam tool40including a multi-beam inspection tool that is part of the exemplary charged particle beam inspection apparatus100ofFIG.1. Multi-beam electron beam tool40(also referred to herein as apparatus40) comprises an electron source201, a gun aperture plate271, a condenser lens210, a source conversion unit220, a primary projection apparatus230, a motorized stage209, and a sample holder207. The electron source201, the gun aperture plate271, the condenser lens210, the source conversion unit220are the components of an illumination apparatus comprised by the multi-beam electron beam tool40. The sample holder207is supported by motorized stage209so as to hold a sample208(e.g., a substrate or a mask) for inspection. Multi-beam electron beam tool40may further comprise a secondary projection apparatus250and an electron detection device240. Primary projection apparatus230may comprise an objective lens231. Electron detection device240may comprise a plurality of detection elements241,242, and243. A beam separator233and a deflection scanning unit232may be positioned inside primary projection apparatus230.

The components that are used to generate a primary beam may be aligned with a primary electron-optical axis of the apparatus40. These components can include: the electron source201, the gun aperture plate271, the condenser lens210, the source conversion unit220, the beam separator233, the deflection scanning unit232, and the primary projection apparatus230. Secondary projection apparatus250and its associated electron detection device240may be aligned with a secondary electron-optical axis251of apparatus40.

The primary electron-optical axis204is comprised by the electron-optical axis of the of the part of electron beam tool40that is the illumination apparatus. The secondary electron-optical axis251is the electron-optical axis of the of the part of electron beam tool40that is a detection apparatus. The primary electron-optical axis204may also be referred to herein as the primary optical axis (to aid ease of reference) or charged particle optical axis. The secondary electron-optical axis251may also be referred to herein as the secondary optical axis or the secondary charged particle optical axis.

Electron source201may comprise a cathode (not shown) and an extractor or anode (not shown). During operation, electron source201is configured to emit electrons as primary electrons from the cathode. The primary electrons are extracted or accelerated by the extractor and/or the anode to form a primary electron beam202that forms a primary beam crossover (virtual or real)203. Primary electron beam202may be visualized as being emitted from primary beam crossover203.

In this arrangement a primary electron beam, by the time it reaches the sample, and preferably before it reaches the projection apparatus, is a multi-beam. Such a multi-beam can be generated from the primary electron beam in a number of different ways. For example, the multi-beam may be generated by a multi-beam array located before the cross-over, a multi-beam array located in the source conversion unit220, or a multi-beam array located at any point in between these locations. A multi-beam array may comprise a plurality of electron beam manipulating elements arranged in an array across the beam path. Each manipulating element may influence the primary electron beam to generate a sub-beam. Thus, the multi-beam array interacts with an incident primary beam path to generate a multi-beam path down-beam of the multi-beam array.

The gun aperture plate271, in operation, is configured to block off peripheral electrons of primary electron beam202to reduce the Coulomb effect. The Coulomb effect may enlarge the size of each of probe spots221,222, and223of primary sub-beams211,212,213, and therefore deteriorate inspection resolution. The gun aperture plate271may also be referred to as a coulomb aperture array.

The condenser lens210is configured to focus the primary electron beam202. The condenser lens210may be designed to focus the primary electron beam202to become a parallel beam and be normally incident onto source conversion unit220. The condenser lens210may be an adjustable condenser lens that may be configured so that the position of its first principle plane is movable. The adjustable condenser lens may be configured to be magnetic. The condenser lens210may be an anti-rotation condenser lens and/or it may be adjustable.

The source conversion unit220may comprise an image-forming element array, an aberration compensator array, a beam-limit aperture array, and a pre-bending micro-deflector array. The pre-bending micro-deflector array may deflect a plurality of primary sub-beams211,212,213of primary electron beam202to normally enter the beam-limit aperture array, the image-forming element array, and an aberration compensator array. In this arrangement, the image-forming element array may function as a multi-beam array to generate the plurality of sub-beams in the multi-beam path, i.e. primary sub-beams211,212,213. The image forming array may comprise a plurality electron beam manipulators such as micro-deflectors micro-lenses (or a combination of both) to influence the plurality of primary sub-beams211,212,213of primary electron beam202and to form a plurality of parallel images (virtual or real) of primary beam crossover203, one for each of the primary sub-beams211,212, and213. The aberration compensator array may comprise a field curvature compensator array (not shown) and an astigmatism compensator array (not shown). The field curvature compensator array may comprise a plurality of micro-lenses to compensate field curvature aberrations of the primary sub-beams211,212, and213. The astigmatism compensator array may comprise a plurality of micro-stigmators to compensate astigmatism aberrations of the primary sub-beams211,212, and213. The beam-limit aperture array may be configured to limit diameters of individual primary sub-beams211,212, and213.FIG.2shows the three primary sub-beams211,212, and213as an example, and it should be understood that the source conversion unit220may be configured to form any number of primary sub-beams. The controller50may be connected to various parts of charged particle beam inspection apparatus100ofFIG.1, such as the source conversion unit220, the electron detection device240, the primary projection apparatus230, or the motorized stage209. As explained in further detail below, the controller50may perform various image and signal processing functions. The controller50may also generate various control signals to govern operations of the charged particle beam inspection apparatus, including the charged particle multi-beam apparatus.

The condenser lens210may further be configured to adjust electric currents of primary sub-beams211,212,213down-beam of the source conversion unit220by varying the focusing power of the condenser lens210. Alternatively, or additionally, the electric currents of the primary sub-beams211,212,213may be changed by altering the radial sizes of beam-limit apertures within the beam-limit aperture array corresponding to the individual primary sub-beams The electric currents may be changed by both altering the radial sizes of beam-limit apertures and the focusing power of the condenser lens210. If the condenser lens is adjustable and magnetic, off-axis sub-beams212and213may result that illuminate the source conversion unit220with rotation angles. The rotation angles change with the focusing power or the position of the first principal plane of the movable condenser lens. The condenser lens210that is an anti-rotation condenser lens may be configured to keep the rotation angles unchanged while the focusing power of the condenser lens210is changed. Such a condenser lens210that is also adjustable, may cause the rotation angles to not change when the focusing power of the condenser lens210and the position of its first principal plane are varied.

The objective lens231may be configured to focus sub-beams211,212, and213onto the sample208for inspection and may form the three probe spots221,222, and223on the surface of sample208.

Beam separator233may, for example, be a Wien filter comprising an electrostatic deflector generating an electrostatic dipole field and a magnetic dipole field (not shown inFIG.2). In operation, beam separator233may be configured to exert an electrostatic force by electrostatic dipole field on individual electrons of primary beamlets211,212, and213. The electrostatic force is equal in magnitude but opposite in direction to the magnetic force exerted by magnetic dipole field of beam separator233on the individual electrons. Primary beamlets211,212, and213may therefore pass at least substantially straight through beam separator233with at least substantially zero deflection angles.

The deflection scanning unit232, in operation, is configured to deflect the primary sub-beams211,212, and213to scan the probe spots221,222, and223across individual scanning areas in a section of the surface of the sample208. In response to incidence of the primary sub-beams211,212, and213or the probe spots221,222, and223on sample208, electrons are generated from the sample208and include secondary electrons and backscattered electrons. The secondary electrons propagate in three secondary electron beams261,262, and263. The secondary electron beams261,262, and263typically have secondary electrons (having electron energy ≤50 eV) and may also have at least some of the backscattered electrons (having electron energy between 50 eV and the landing energy of primary sub-beams211,212, and213). The beam separator233is arranged to deflect the path of the secondary electron beams261,262, and263towards the secondary projection apparatus250. The secondary projection apparatus250subsequently focuses the path of secondary electron beams261,262, and263onto a plurality of detection regions241,242, and243of electron detection device240. The detection regions may be separate detection elements241,242, and243that are arranged to detect corresponding secondary electron beams261,262, and263. The detection regions generate corresponding signals, which are sent to the controller50or a signal processing system (not shown), e.g. to construct images of the corresponding scanned areas of the sample208.

The detection elements241,242, and243may detect the corresponding secondary electron beams261,262, and263. On incidence of secondary electron beams with the detection elements241,242and243, the elements may generate corresponding intensity signal outputs (not shown). The outputs may be directed to an image processing system (e.g., controller50). Each detection element241,242, and243may comprise one or more pixels. The intensity signal output of a detection element may be a sum of signals generated by all the pixels within the detection element.

The controller50may comprise image processing system that includes an image acquirer (not shown) and a storage device (not shown). For example, the controller may comprise a processor, computer, server, mainframe host, terminals, personal computer, any kind of mobile computing devices, and the like, or a combination thereof. The image acquirer may comprise at least part of the processing function of the controller. Thus, the image acquirer may comprise at least one or more processors. The image acquirer may be communicatively coupled to the electron detection device240of the apparatus40permitting signal communication, such as an electrical conductor, optical fiber cable, portable storage media, IR, Bluetooth, internet, wireless network, wireless radio, among others, or a combination thereof. The image acquirer may receive a signal from the electron detection device240, may process the data comprised in the signal and may construct an image therefrom. The image acquirer may thus acquire images of the sample208. The image acquirer may also perform various post-processing functions, such as generating contours, superimposing indicators on an acquired image, and the like. The image acquirer may be configured to perform adjustments of brightness and contrast, etc. of acquired images. The storage may be a storage medium such as a hard disk, flash drive, cloud storage, random access memory (RAM), other types of computer readable memory, and the like. The storage may be coupled with the image acquirer and may be used for saving scanned raw image data as original images, and post-processed images.

The image acquirer may acquire one or more images of a sample based on an imaging signal received from the electron detection device240. An imaging signal may correspond to a scanning operation for conducting charged particle imaging. An acquired image may be a single image comprising a plurality of imaging areas. The single image may be stored in the storage. The single image may be an original image that may be divided into a plurality of regions. Each of the regions may comprise one imaging area containing a feature of sample208. The acquired images may comprise multiple images of a single imaging area of sample208sampled multiple times over a time period. The multiple images may be stored in the storage. The controller50may be configured to perform image processing steps with the multiple images of the same location of sample208.

The controller50may include measurement circuitry (e.g., analog-to-digital converters) to obtain a distribution of the detected secondary electrons. The electron distribution data, collected during a detection time window, can be used in combination with corresponding scan path data of each of primary sub-beams211,212, and213incident on the sample surface, to reconstruct images of the sample structures under inspection. The reconstructed images can be used to reveal various features of the internal or external structures of sample208. The reconstructed images can thereby be used to reveal any defects that may exist in the sample.

The controller50may control the motorized stage209to move the sample208during inspection of the sample208. The controller50may enable the motorized stage209to move the sample208in a direction, preferably continuously, for example at a constant speed, at least during sample inspection. The controller50may control movement of the motorized stage209so that it changes the speed of the movement of the sample208dependent on various parameters. For example, the controller may control the stage speed (including its direction) depending on the characteristics of the inspection steps of scanning process.

AlthoughFIG.2shows that the apparatus40uses three primary electron sub-beams, it is appreciated that the apparatus40may use two or more number of primary electron sub-beams. The present disclosure does not limit the number of primary electron beams used in the apparatus40.

Reference is now made toFIG.3A, which is a schematic diagram of exemplary multi-beam apparatus illustrating an exemplary configuration of source conversion unit of the exemplary charged particle beam inspection apparatus ofFIG.1. The apparatus300may comprise an election source301, a pre-sub-beam-forming aperture array372, a condenser lens310(similar to condenser lens210ofFIG.2), a source conversion unit320, an objective lens331(similar to objective lens231ofFIG.2), and a sample308(similar to sample208ofFIG.2). The election source301, the pre-sub-beam-forming aperture array372, the condenser lens310may be the components of an illumination apparatus comprised by the apparatus300. The source conversion unit320and the objective lens331may be the components of a projection apparatus comprised by the apparatus300. The source conversion unit320may be similar to source conversion unit220ofFIG.2in which the image-forming element array ofFIG.2is image-forming element array322, the aberration compensator array ofFIG.2is aberration compensator array324, the beam-limit aperture array ofFIG.2is beam-limit aperture array321, and the pre-bending micro-deflector array ofFIG.2is pre-bending micro-deflector array323. The election source301, the pre-sub-beam-forming aperture array372, the condenser lens310, the source conversion unit320and the objective lens331are aligned with a primary electron-optical axis304of the apparatus. The electron source301generates a primary-electron beam302generally along the primary electron-optical axis304and with a source crossover (virtual or real)3015. The pre-sub-beam-forming aperture array372cuts the peripheral electrons of primary electron beam302to reduce a consequential Coulomb effect. The Coulomb effect is a source of aberration to the sub-beams due to interaction between electrons in different sub-beam paths. Primary-electron beam302may be trimmed into a specified number of sub-beams, such as three sub-beams311,312and313by the pre-sub-beam-forming aperture array372of a pre-sub-beam-forming mechanism. Although three sub-beams and their paths are referred to in the previous and following description, it should be understood that the description is intended to apply an apparatus, tool, or system with any number of sub-beams.

The source conversion unit320may include a beamlet-limit aperture array321with beam-limit apertures configured to limit the sub-beams311,312, and313of the primary electron beam302. The source conversion unit320may also include an image-forming element array322with image-forming micro-deflectors,322_1,322_2, and322_3. There is a respective micro-deflector associated with the path of each sub-beam. The micro-deflectors322_1,322_2, and322_3are configured to deflect the paths of the sub-beams311,312, and313towards the electron-optical axis304. The deflected sub-beams311,312and313form virtual images of source crossover301S. The virtual images are projected onto the sample308by the objective lens331and form probe spots thereon, which are the three probe spots,391,392, and393. Each probe spot corresponds to the location of incidence of a sub-beam path on the sample surface. The source conversion unit320may further comprise an aberration compensator array324configured to compensate aberrations of each of the sub-beams. The aberrations in each sub-beam are typically present on the probe spots,391,392, and393that would be formed a sample surface. The aberration compensator array324may include a field curvature compensator array (not shown) with micro-lenses. The field curvature compensator and micro-lenses are configured to compensate the sub-beams for field curvature aberrations evident in the probe spots,391,392, and393. The aberration compensator array324may include an astigmatism compensator array (not shown) with micro-stigmators. The micro-stigmators are controlled to operate on the sub-beams to compensate astigmatism aberrations that are otherwise present in the probe spots,391,392, and393.

The source conversion unit320may further comprise a pre-bending micro-deflector array323with pre-bending micro-deflectors323_1,323_2, and323_3to bend the sub-beams311,312, and313respectively. The pre-bending micro-deflectors323_1,323_2, and323_3may bend the path of the sub-beams onto the beamlet-limit aperture array321. The sub-beam path of the incident on beamlet-limit aperture array321may be orthogonal to the plane of orientation of the beamlet-limit aperture array321. The condenser lens310may direct the path of the sub-beams onto the beamlet-limit aperture array321. The condenser lens310may focus the three sub-beams311,312, and313to become parallel beams along the primary electron-optical axis304, so that it is perpendicularly incident onto the source conversion unit320, which may correspond to the beamlet-limit aperture array321.

The image-forming element array322, the aberration compensator array324, and the pre-bending micro-deflector array323may comprise multiple layers of sub-beam manipulating devices, some of which may be in the form or arrays, for example: micro-deflectors, micro-lenses, or micro-stigmators.

In the source conversion unit320, the sub-beams311,312and313of the primary electron beam302are respectively deflected by the micro-deflectors322_1,322_2and322_3of image-forming element array322towards the primary electron-optical axis304. It should be understood that the path of sub-beam311may already correspond to the electron-optical axis304prior to reaching micro-deflector322_1, accordingly the path of sub-beam311may not be deflected by micro-deflector322_1.

The objective lens331focuses the sub-beams onto the surface of the sample308, i.e., it projects the three virtual images onto the sample surface. The three images formed by three sub-beams311to313on the sample surface form three probe spots391,392and393thereon. The deflection angles of sub-beams311to313are adjusted by the objective lens311to reduce the off-axis aberrations of three probe spots391-393. The three deflected sub-beams consequently pass through or approach the front focal point of objective lens331.

At least some of the above-described components inFIG.2andFIG.3Amay individually, or in combination with each other, be referred to as a manipulator array, or manipulator, because they manipulate one or more beams, or sub-beams, of charged particles.

The above described multi-beam inspection tool comprises a multi-beam charged particle optical apparatus with a single source of charged particles. The charged particle optical apparatus comprises an illumination apparatus and a projection apparatus. The illumination apparatus may generate a multi-beam of charged particles from the beam of electrons from the source. The projection apparatus projects a multi-beam of charged particles towards a sample. At least part of the surface of a sample is scanned with the multi-beam of charged particles

As an example of an array, a 3×3 image-forming micro-deflector array configuration that can deflect a total of nine beamlets simultaneously is illustrated inFIG.3B.FIG.3Billustrates that each of image-forming micro-deflectors322_1,322_2, or322_3comprises4electrodes. As the number of beamlets increases, the size of the array may tend to increase in size as well. Note although an array of nine deflector assemblies (generally manipulators) is shown, arrays can exist from this arrangement to five by five, seven by seven, eleven by eleven to as many as 5000 or more manipulators.

As shown above, a multi-beam projection tool such as SEM among other can include a great number of beam manipulators such as, but not limited to, micro-deflectors, micro-lenses, or micro-stigmators. As the physical sizes of IC components continue to shrink, accuracy of manipulating each of the beams in a multi-beam projection tool becomes more important. Even a small beam aberration caused by a micro beam manipulator can invoke a false defect detection from the finished IC, which can substantially degrade overall yield of the process. In SEM, multiple electron beams are aligned in the column with a small pitch (e.g., 300 micrometer or less) and every beam is manipulated by electric fields generated by electrodes of beam manipulators. Note that in this description an electrode is intended to refer to an electrically conductive element providing a surface that directly electro-statically interacts with the charged particles as the pass by the electrode along its beam or beamlet path. However, dielectric or electrically isolating material in the vicinity of electron beam passages can be charged and cause distortions of electric fields formed in the passages. Such electric field distortion can lead to degradation of electron-optical properties of beam manipulators. That is, electric field distortion can cause beam aberrations. To avoid such electric field distortion in beam manipulators, forming a uniform electric field in the beam passages of beam manipulators during operation can help alleviate these issues. This can be achieved by implementing uniform charge distribution on beam passage forming surfaces of beam manipulators.

Although beam manipulators are described with respect to a charged particle beam inspection system (e.g., SEM), the disclosure is not so limited. The present disclosure can be applied to beam manipulators utilized in other types of electron optical systems such as illumination systems, projection systems, charged-particle metrology tools, e-beam lithography tools, e-beam inspection systems, etc. It will be also appreciated that the present disclosure can be applied to embodiments in which multiple beam manipulators are aligned in an array, for example, illustrated inFIG.3Bwhile the disclosure will be explained with respect to one beam manipulator.

Reference is now made toFIG.4Aillustrating a schematic plan view of an exemplary beam manipulator, consistent with embodiments of the present disclosure.FIG.4Bis a schematic cross-sectional perspective view of the beam manipulator ofFIG.4A. A beam manipulator400ofFIG.4Acan be formed based on an electrically non-conductive substrate in various embodiments. For example, a substrate can be a silicon substrate. As shown inFIG.4B, a beam manipulator400may include a substrate440and one or more electrodes411. An aperture430extending through two opposing surfaces of substrate440is formed in the substrate440. The two opposing surfaces of substrate440can constitute major surfaces of substrate440. The two opposing surfaces may include an upper surface401and a lower surface402of the substrate440. In this disclosure, a term “upper” can refer to an upper side of a component and a term “lower” can refer to a lower side of a component. However, such terms are of convenience since a beam manipulator400need not be orientated in use in alignment with a gravitational field; the terms “upper” and “lower,” and the like, may refer to the orientation of substrate440with the intended beam direction.

In some embodiments, one or more electrodes411can be formed around aperture430as shown in plan view inFIG.4A. For example, one or more electrodes411can be positioned adjacent to aperture430and can be positioned in upper surface401of substrate440. For example, aperture facing surfaces of one or more electrodes411can form a part of aperture430. InFIG.4A, the aperture facing surface of the electrode411is shown as a part of a rim defining the aperture430in the upper surface of the substrate. In some embodiments, the aperture430can have a substantially circular shape (e.g., boundary C). The one or more electrodes411extend radially outwardly from aperture430. In some embodiments, the one or more electrodes411form a portion of upper surface401. For example, the one or more electrodes411may be positioned between aperture430and a certain boundary (such as boundary B). In some embodiments, the certain boundary may surround the aperture430. The certain boundary may be circular and the aperture430substantially surrounded by the circular boundary may be substantially circular.

In various embodiments where a beam manipulator400has a plurality of electrodes, such as four electrodes411as shown inFIG.4A, two adjacent electrodes among the plurality of electrodes411may be spaced apart. Mutually facing surfaces of two adjacent electrodes may define a gap therebetween. For example, two facing surfaces of two adjacent electrodes may be spaced apart by a gap431. In some embodiments, the facing surfaces defining gap431may be parallel as shown inFIG.4A. In some other embodiments, the facing surfaces defining gap431may be radially diverging. Gap431may have a consistent tangential dimension along its radial length. In some embodiments, a gap (such as gap431) can have a radial length longer than a radial length of electrode411to enhance electrical isolation between two adjacent electrodes. Here, a radial length of electrode411can correspond to a radial distance between boundary B to boundary C. It will be noted that the boundaries B and C are assumed to be continuous in that the gaps431do interfere or even disrupt boundaries B and C.

In some embodiments, gap431can extend through substrate440between upper surface401and lower surface402as shown inFIG.4B. The gap431can extend through an entire length of the beam manipulator400. Resulting from the gap431formed in the substrate440, the substrate440can have one or more protruding portions451. Each protruding portion451comprises its respective electrode411, such that the electrode411provides at least one surface of the protruding portion451such as an upper surface of the electrode411. Each protruding portion451is, in plan view, radially inwardly protruding from a base surface471of the substrate440. In some embodiments, base surface471can an external, uncovered portion of the substrate440's body. In some embodiments, the base surface471includes a substantially vertical surface extending between the lower surface and the electrode411that provides the upper surface of the substrate440and major surfaces of the substrate440. In some embodiments, the base surface471may not be flat between the lower surface402and the electrode411. The base surface471may be a surface uncovered by the gap431and positioned remote from the aperture430such that the gap431is open to the aperture430side and closed on the other side by the base surface471. Base surface471may be positioned at or radially outside of boundary B relative to the aperture to enhance electrical isolation between two electrodes411on two adjacent protruding portions451. In some embodiments, base surface471can extend from an upper surface of beam manipulator400to lower surface402of substrate440. Each of the one or more protruding portions451has two or more side surfaces facing gaps adjacent to the corresponding protruding portion. For example, protruding portion451can have a first side surface451S1and a second side surface451S2that are surfaces of the protruding portion451extending through the substrate440, apart from the radially inwardly facing aperture surface451S3. In some embodiments, protruding portions451have aperture facing surfaces451S3, each of which meets with first side surface451S1and with second side surface451S2of corresponding protruding portion451. In some embodiments, each of the protruding portions451extends from the upper surface401to the lower surface402of the substrate440.

According to embodiments of the present disclosure, while beam manipulator400is shown as having four electrodes411inFIG.4AandFIG.4B, it is appreciated that manipulator400can have any number of electrodes, for example, eight electrodes, ten electrodes, twelve electrode, and so on. In some embodiments, beam manipulator400can have a single electrode. A single electrode may have an annular, preferably ring, shaped surrounding aperture430. In some embodiments, beam manipulator400may not include a gap, and aperture430can be formed along boundary C and can extend from an upper surface of beam manipulator400to lower surface402of substrate440. In some other embodiments, beam manipulator400may include a gap (e.g., gap431) separating two ends of the same electrode.

According to embodiments of the present disclosure, one or more beams can be manipulated by electric fields generated by beam manipulator400. To generate electric fields to affect trajectories of one or more beams passing through aperture430, electrodes411can be wired individually or collectively to a corresponding power source. The power source is generally positioned outside of an electron column of SEM. In some embodiments, an electric circuit configured to provide a driving voltage or control signal to electrodes411can be formed on a routing or wiring portion420of the upper surface401of the substrate440. The power source can include a voltage driver.

Beam manipulator400including four electrodes such as inFIG.4Acan be configured in different ways to function differently. When all four electrodes are applied to one voltage potential, the beam manipulator400can function as a micro-lens. When the two pairs of opposite electrodes are applied to two voltages of the same absolute value but opposite polarity, the beam manipulator400can function as a micro-stigmator. For example, inFIG.4A, when one pair of electrodes facing each other among the four electrodes411are applied to +V1and the other pair of electrodes facing each other are applied to −V1, the beam manipulator may function as a micro-stigmator. When to one pair of opposite electrodes a zero voltage is applied, and to the other pair of opposite electrodes two voltages of the same absolute value but having opposite polarity are applied, the beam manipulator can function as a micro-deflector. For example, inFIG.4A, the beam manipulator400can be operated to function as a micro-deflector in the following way. One pair of electrodes facing each other among the four electrodes411can be set at a ground potential, i.e. a potential of zero (0) volts. Of the other pair of electrodes that face each other, to one electrode is applied a potential of V2; and to the other electrode is applied a potential of −V2. A magnitude or polarity of a voltage applied to each of electrodes can be determined according to a target manipulation of a beam passing through the aperture430. The target manipulation may be in terms of direction or degree of the manipulation of the beam as it passes through aperture430. In some embodiments, controller50may be configured to control voltage levels, voltage polarities, voltage application timing, etc. for each electrode included in beam manipulator400. The controller50can be configured to provide a digital signal to the electric circuit configured to provide a driving voltage or control signal to electrodes411.

It will be noted thatFIG.4AandFIG.4Billustrate simplified beam manipulator400omitting one or more elements constituting beam manipulator400and therefore various beam manipulators (e.g.,500,800, etc., which appear later in the description) according to embodiments of the present disclosure can be explained or illustrated based on beam manipulator400shown in and described with respect toFIGS.4A and4B. Beam manipulator400may further include a shielding layer (not shown) positioned upstream of electrode411in a direction of an electron beam when operating. The shielding layer may enable avoiding that an electron beam charges an upper surface and/or a boundary (e.g., boundary B) formed on the upper surface. The shielding layer may shield each electron beam from other electron beam in a multiple electrode configuration. The shielding layer can be formed as a conductive layer. The shielding layer can be formed by coating a conductive layer on a non-conductive structure. The shielding layer can be included on any type of beam manipulators such as a beam manipulator500,800,1000,1100,1100′, or1300inFIGS.5,10A,11A,11B, or13of the present disclosure. The shielding layer can be included in any type of stacked beam manipulating devices such as a stacked beam manipulating device700or1400inFIG.7or14, where the shielding layer can be placed on an uppermost manipulator (e.g.,500or1300inFIG.7or14) in a direction of an electron beam during operation.

In the present disclosure, a beam manipulator may be described as including a main body and an electrode. In beam manipulator400ofFIG.4B, substrate440can form a main body of the beam manipulator400and electrode411can be an electrode of the beam manipulator400. A main body can have a first surface and a second surface opposing the first surface and an interconnecting surface extending between the first surface and the second surface and defining an aperture through the body according to embodiments of the present disclosure.

Now reference is made toFIG.5illustrating a cross-section view of exemplary configurations of a beam manipulator500, consistent with embodiments of the present disclosure.FIG.5may show a cross section view of a beam manipulator along an imaginary line A-A′ inFIG.4A. As shown inFIG.5, beam manipulator500can have substrate440having upper surface401and lower surface402and aperture430defined therein according to embodiments of the present disclosure. Aperture430may extend from the upper surface401to the lower surface402of the substrate440. In some embodiments, beam manipulator500may have one or more electrodes411around aperture430and may be positioned on upper surface401of substrate440.

In some embodiments, two electrodes411shown inFIG.5may be electrically separated from each other. For example, the two electrodes411shown inFIG.5can constitute separate electrodes. In some embodiments, two electrodes411shown inFIG.5can be part of a single electrode surrounding aperture430. In some other embodiments, two electrodes411shown inFIG.5can function as one electrode by electrically connecting the two electrodes411.

According to embodiments of the present disclosure, substrate440may have aperture facing surfaces451S3extending from upper surface401to lower surface402and facing aperture430. In some embodiments, aperture facing surfaces451S3can be configured to have a uniform charge distribution. In some embodiments, beam manipulator500can be configured to have uniform charge distribution on entire aperture facing surfaces451S3from upper surface401to lower surface402of substrate440.

In some embodiments, two aperture facing surfaces451S3shown inFIG.5can be part of one continuous aperture facing surface of the substrate440. In this example, beam manipulator500can include a single electrode and no gaps (e.g., gaps431ofFIG.4B) are formed in beam manipulator500. In some embodiments, a plurality of gaps may be defined in beam manipulator500and the substrate440may include a plurality of protruding portions451. Side surfaces (e.g.,451S1and451S2ofFIG.4B) of the protruding portions451can also be configured to have even charge distribution between upper surface401and lower surface402. The side surfaces of protruding portions451can have even charge distribution equal to even charge distribution of the aperture facing surfaces451S3.

In some embodiments, aperture facing surfaces451S3of substrate440can be coated with a first conductive layer481, consistent with embodiments of the present disclosure. A first conductive layer481may coat entire aperture facing surface451S3from upper surface401to lower surface402of substrate440. The first conductive layer481may be a coating and/or may extend to at least part of lower surface402of the substrate440. The first conductive layer481may provide a bottom surface of corresponding protruding portion451, preferably as a coating. The first conductive layer481may cover the entire lower surface402of substrate440.

The first conductive layer481may be configured to have an electric potential different from an electric potential of electrode411. In order to avoid a short circuit between electrode411and first conductive layer481when forming first conductive layer481, beam manipulator500can further include a second conductive layer461on at least part of upper surface401of the substrate440. In some embodiments, second conductive layer461can be positioned between electrode and upper surface401of the substrate440. According to embodiments of the present disclosure, first conductive layer481can be electrically connected with second conductive layer461. In some embodiments, first conductive layer481can have the same electric potential with second conductive layer461when beam manipulator500is operating. For example, first conductive layer481and second conductive layer461can be electrically connected to a common power source via electric circuits through a routing portion421. In some embodiments, first conductive layer481and/or second conductive layer461can function as a shielding layer. For example, first conductive layer481and second conductive layer461can be provided with a ground voltage. By shielding beam facing surface451S3of substrate440, a distortion of an electric field in the aperture430by substrate material facing the aperture430can be avoided or reduced.

In beam manipulator500ofFIG.5, substrate440, first conductive layer481, and second conductive layer461can form a main body of the beam manipulator500, and electrode411can be an electrode of the beam manipulator500. According to embodiments of the present disclosure, a main body can comprise an elongated electrode that forms the interconnecting surface between the first surface and the second surface. In various embodiments including a beam manipulator (e.g., illustrated inFIG.5), first conductive layer481can be an elongate electrode of the main body. In some embodiments, second conductive layer461can form a first surface of the main body. In some embodiments, beam manipulator500ofFIG.5further includes an electrical isolator between second conductive layer461and electrode411so that different potentials can be applied to the second conductive layer461and electrode411.

FIG.6illustrates an exemplary method of forming beam manipulator500ofFIG.5, consistent with embodiments of the present disclosure. As shown inFIG.6, in step A1, a workpiece is provided. The workpiece can include a substrate600having a first surface601and a second surface602, an electrode layer610, and a conductive layer661. The substrate600can be made of silicon, doped silicon, glass (e.g., pyrex), and so on.

Electrode layer610may be formed relative to first surface601of substrate600. In some embodiments, electrode layer610may include electrode portions611spaced apart by a dielectric613. According to embodiments, electrode portions611can be formed to constitute electrodes411in beam manipulator500ofFIG.5upon completion of forming the beam manipulator500. According to embodiments, dielectric613can have a pattern corresponding to an intended aperture (e.g., aperture430ofFIG.4A), which can have a substantially circular shape (e.g., boundary C) from a top view. In some embodiments where a plurality of electrodes are included in a beam manipulator, the pattern of dielectric613can be more spoke-shaped. For example, as shown inFIG.4A, the pattern of dielectric613can include not only boundary C but also the patterns, e.g. the radially outwardly extending shapes from the boundary C, corresponding to gaps431. In some embodiments, electrode layer610may further include a routing portion621. In some embodiments, routing portion621can be positioned adjacent to electrode portion611and outer to the electrode portion611with respect to the dielectric613.

In some embodiments, a workpiece can further comprise a conductive layer661between electrode layer610and upper surface601of the substrate600. According to embodiments, conductive layer661can be formed to constitute second conductive layer461in beam manipulator500ofFIG.5upon completion of forming the beam manipulator500. The workpiece can further comprise an electrical insulator (not shown) between electrode portion611and conductive layer661. This enables that different potential are applied to an electrode (formed from electrode portion611) and second conductive layer (formed from conductive layer661) in a resulting beam manipulator avoiding short circuiting. In some embodiments, conductive layer661may include an opening662positioned in an area corresponding to dielectric613. In some embodiments, a width of the opening662can be smaller than or equal to a width of the dielectric613. When the width of the opening662is smaller than a width of the dielectric613, the conductive layer661may at least partially shield their corresponding electrodes to minimize sputtered conductive material from accumulating on electrode portions611at step A6. Step A6will be further explained below.

While a method of forming a beam manipulator ofFIG.5is explained based on a workpiece of step A1, it will be appreciated that the present disclosure can be applied to a method of forming a beam manipulator, which further includes one or more steps for manufacturing the workpiece of step A1such as, but not limited to, cleansing a substrate, forming electrode layer610on substrate600, etc.

In step A2, a first resist layer630is formed on second surface602of substrate600. The first resist layer630may be a negative or positive resist. In some embodiments, first resist layer630may include an opening631corresponding to an area of the dielectric613. Therefore, opening631in the first resist layer630can have a pattern corresponding to an intended aperture (e.g., aperture430ofFIG.4A). For example, opening631can have a shape corresponding to boundary C inFIG.4A). The opening can have a substantially circular shape from a top view. In some embodiments where a plurality of electrodes411are included in a beam manipulator, the pattern of opening631can include not only boundary C but also the patterns corresponding to gaps (e.g., gaps431ofFIG.4A), for example radially extending portions periodically distributed around the periphery of the substantially circular shape. In some embodiments, first resist layer630can be aligned to cover the electrode portions611from a top view.

In step A3, substrate600can be etched through opening631in first resist layer630. In some embodiments, hole632can be formed extending from first surface601to second surface602of the substrate600. Substrate600may be etched by DRIE (deep reactive ion etching) allowing high aspect ratio, RIE (reactive ion etching) such as plasma etching, etc. In some embodiments, substrate600can be etched by, but not limited to, a Bosch Process that is a high-aspect ratio plasma etching process. According to embodiments of the present disclosure, an aperture (e.g., such as aperture430) and any gaps (e.g., gaps431ofFIG.4A) can be etched simultaneously at step A3because opening631of first resist layer corresponds to an area of the dielectric613and the dielectric613can have a pattern corresponding to the aperture430and gaps431. In step A3, dielectric613may function as a stop layer for the etching process when etching the substrate600. In some embodiments, a width of hole632may be wider than a width of the opening662in the conductive layer661so that a part of the conductive layer661around the hole632can be exposed by the etching process as shown at step A3ofFIG.6.

In step A4, a second resist layer640can be formed on electrode layer610. The second resist layer640may be a negative or positive resist. In some embodiments, second resist layer640can have an opening641corresponding to an area of the dielectric613. In order to assure that the dielectric613is removed by a subsequent etching process, the opening641may have a wider width than a width of the dielectric613. For example, a part of electrode portion611may not be covered by second resist layer640as shown at step A4ofFIG.6.

In step A5, dielectric613can be etched through opening641of second resist layer640. Dielectric613can be etched by a wet or dry etching (e.g., RIE etching) process while routing portion621is protected by second resist layer640. In some embodiments, an etching process for removing the dielectric613can be performed by material that does not etch electrode portion611so that a part of the electrode portion611, which is not covered by second resist layer640, is not etched away during the etching process. By removing the dielectric613at step A5, a hole633extending from second surface602of substrate600to electrode portion611can be formed, which can constitute an aperture in a beam manipulator (e.g., an aperture430inFIG.5). In some embodiments, at step A5, any gaps (e.g., gaps431ofFIG.4A) between adjacent electrodes can also be formed in electrode layer610. Step A5may include removing the second resist layer640after the dielectric613is removed.

In step A6, a second conductive layer680can be formed on a hole facing surface of substrate600, which extends from first surface601to second surface602of the substrate600. In some embodiments, second conductive layer680can be formed to constitute a first conductive layer (e.g., first conductive layer481in beam manipulator500ofFIG.5) upon completion of forming the beam manipulator. In some embodiments, second conductive layer680can be formed on the second surface602of the substrate600. In some embodiments, second conductive layer680can be coated on second surface602of substrate600and a hole facing surface of substrate600. In some embodiments, second conductive layer680can be coated by sputtering conductive material from a second surface side of substrate600as indicated as arrows at step A6inFIG.6. Second conductive layer680can also be coated by evaporation deposition process, sputtering deposition, etc. At step A6, conductive layer661can prevent second conductive layer670from contacting with electrode portion611. In some embodiments, because conductive layer661is protruded into hole633than electrode portion611, accumulation of the sputtered conductive material of the second conductive layer680on the electrode portion611can be minimized or removed, for example, by a shadowing effect. Thereby, a short circuit between second conductive layer680and electrode portion611can be prevented. In some embodiments where a beam manipulator includes one or more gaps (e.g., gap431ofFIG.4B) and one or more protruding portions (e.g., protruding portion451ofFIG.4B), second conductive layer680can be further formed on side surfaces of protruding portions (e.g.,451S1and451S2ofFIG.4B).

As explained above, the fabricating process illustrated inFIG.6can be used for fabricating beam manipulator500ofFIG.5. It will be noted that beam manipulator500ofFIG.5can be obtained by turning the workpiece at step A6upside down.

FIG.7is a cross section view of exemplary configurations of a stacked beam manipulating device, consistent with embodiments of the present disclosure. As shown inFIG.7, a stacked beam manipulating device700can be formed by placing a first beam manipulator500on top of a second beam manipulator500′. In some embodiments, each of first beam manipulator500and second beam manipulator500′ can be beam manipulator500ofFIG.5. According to embodiments of the present disclosure, first beam manipulator500can be positioned on top of second beam manipulator500′ such that first conductive layer481coated on lower surface402of substrate440may contact with electrode411′ of second beam manipulator500′. In some embodiments, first conductive layer481can function as a shielding layer. Thus, the first conductive layer481may provide a shielding function with respect to a down-beam manipulator, for example, the second beam manipulator500′. Thereby, an additional shielding process or securing process (e.g., bonding/gluing) can be omitted when stacking two beam manipulators. For example, an additional shielding layer between first beam manipulator500and second beam manipulator500′ can be omitted when stacking first beam manipulator500and second beam manipulator500′. To ensure that the conductive layer481and adjoining down beam electrode411′ (made of a conductive material) are isolated, an isolator layer (not shown) may be between the first beam manipulator500and the second beam manipulator500. For example, an isolator layer may be between at least the portion of the conductive layer481on the lower surface402of a first beam manipulator500and the down beam electrode411′.

According to embodiments of the present disclosure, a yield rate of forming a stacked beam manipulator can be improved. According to embodiments of the present disclosure, accuracy of aligning multiple beam manipulators for a stacked beam manipulating device can be improved by combining a shield layer and a beam manipulating electrode in one element. In some embodiments, alignment error of stacking multiple beam manipulators can be decreased to order of hundreds of nanometers. When using staked beam manipulating device700according to embodiments of the present disclosure, beam aberration can be reduced, for example, through improved alignment of multiple beam manipulators. According to embodiments of the present disclosure, a stacked beam manipulating device can be efficiently manufactured by omitting additional shielding processes or bonding processes between adjacent beam manipulators. According to embodiments of the present disclosure, deflection strength can be increased by stacking multiple beam manipulators. WhileFIG.7illustrates that two beam manipulators500and500′ are stacked, it is appreciated that the present disclosure can also be applied when three or more beam manipulators are stacked to obtain a target cumulative deflection strength.

AlthoughFIG.7illustrates that each of beam manipulators500and500′ in stacked beam manipulating device700includes its own corresponding routing portion421or421′, it is appreciated that only one of the stacked beam manipulators500and500′ can have a routing portion and the other beam manipulator may not have its own routing portion. For example, second beam manipulator500′ may not have its own routing portion and may be wired to routing portion421of first beam manipulator500. In this example, there can be an electrical connection between first electrode layer481of first beam manipulator500and electrode411′ of second beam manipulator500′. According to embodiments, resources can be saved in manufacturing a stacked manipulating device

Now reference is made toFIG.8illustrating a cross section view of exemplary configurations of a beam manipulator, consistent with embodiments of the present disclosure. The duplicated explanation regarding elements of a beam manipulator800may be omitted for simplicity.FIG.8may show a cross section view of a beam manipulator along an imaginary line A-A′ inFIG.4A. As shown inFIG.8, beam manipulator800can have a substrate840having an upper surface801and a lower surface802and an aperture830formed therein according to embodiments of the present disclosure. Aperture830can extend between the upper surface801and the lower surface802of the substrate840. In some embodiments, beam manipulator800may have one or more electrode contacts811around aperture830and may be positioned on upper surface801of substrate840.

In some embodiments, two electrode contacts811shown inFIG.8may be electrically separated from each other. For example, the two electrode contacts811shown inFIG.8can constitute separate electrode contacts. In some embodiments, the two electrode contacts811shown inFIG.8can be part of a single electrode contact surrounding aperture830, which may be rotationally symmetrical around a beamlet path. In some embodiments, the two electrode contacts811shown inFIG.8can function as one electrode contact by electrically connecting the two electrode contacts811.

According to embodiments of the present disclosure, substrate840may have aperture facing surfaces851S3extending from upper surface801to lower surface802and facing aperture830. In some embodiments, aperture facing surfaces851S3can be configured to provide a uniform charge distribution during operation. In some embodiments, beam manipulator800can be configured to provide a uniform charge distribution during operation on entire aperture facing surfaces851S3from upper surface801to lower surface802.

In some embodiments, aperture facing surfaces851S3can be part of one surface forming aperture830. In this example, beam manipulator800can include a single electrode contact and gaps (e.g., gaps431ofFIG.4B) are not formed in beam manipulator800. In some embodiments, a plurality of gaps may be formed in beam manipulator800and the substrate840can include a plurality of protruding portions851. Side surfaces (e.g.,451S1and451S2ofFIG.4B) of the protruding portions851can also be configured to have even charge distribution between upper surface801and lower surface802during use, consistent with embodiments of the present disclosure. Here, the side surfaces of protruding portions851can have, during use, even charge distribution equal to even charge distribution of the aperture facing surfaces851S3. According to embodiments, aperture facing surfaces851S3can have, during use, even charge distribution equal to charge distribution of their corresponding electrode811. In some embodiments, during use, side surfaces (e.g.,451S1and451S2ofFIG.4B) as well as aperture facing surfaces851S3can have even charge distribution equal to charge distribution of their corresponding electrode811.

In some embodiments, aperture facing surface851S3of substrate840can be coated with a conductive layer881, consistent with embodiments of the present disclosure. In some embodiments, conductive layer881can coat entire aperture facing surface851S3from upper surface801to lower surface802. In some embodiments, conductive layer881can extend to contact with at least part of electrode811of beam manipulator800. For example, conductive layer881can coat at least part of an aperture facing surface of corresponding electrode contact811. In some embodiments, conductive layer881can coat an aperture facing surface and at least part of a top surface of corresponding electrode contact811. As an example,FIG.8illustrates conductive layer881covering aperture facing surface851S3of substrate840, an aperture facing surface of corresponding electrode contact811, and a top surface of the corresponding electrode contact811. According to embodiments, at least part of a base surface (e.g., base surface471ofFIG.4B) between two adjacent protruding portions851should not be covered by conductive layer881to enhance electrical isolation between two corresponding electrodes811.

According to embodiments of the present disclosure, conductive layer881can be configured to have an electrical potential equal to an electrical potential of its corresponding electrode contact811, respectively, during operation. In some embodiments where one or more gaps (e.g., gaps431ofFIG.4B) are included in a beam manipulator, conductive layer881covering one protruding portion can have an electrical potential equal to an electrical potential of an electrode contact associated with the one protruding portion. In some embodiments, a conductive layer881and its corresponding electrode contact811can be provided during operation with the same operating voltage. Here, conductive layer881can function as a beam manipulating electrode in conjunction with corresponding electrode contact811. In some embodiments, conductive layer881or electrode contact811can be connected to a power source via electric circuit placed in the routing area821. According to embodiments of the present disclosure, beam aberration can be reduced in that beam manipulator800can provide a uniform electric field through an entire aperture length.

In beam manipulator800ofFIG.8, substrate840and conductive layer881can form a main body of the beam manipulator800and electrode contact811can be an electrode contact of the beam manipulator800. A main body can comprise an elongated electrode that forms the interconnecting surface between the first surface and the second surface. In various embodiments including beam manipulator (e.g., illustrated inFIG.8), conductive layer881can be an elongated electrode included in the main body.

FIG.9illustrates an exemplary method of forming beam manipulator800ofFIG.8, consistent with embodiments of the present disclosure. As shown inFIG.9, in step B1, a workpiece is provided. The workpiece can include a substrate900having a first surface901and a second surface902and an electrode layer910.

Electrode layer910may be formed on first surface901of substrate900. In some embodiments, electrode layer910may include electrode contact portions911spaced apart by a dielectric913. According to embodiments, electrode contact portions911can be formed to constitute electrode contacts811in beam manipulator800ofFIG.8upon completion of forming the beam manipulator800. According to embodiments, dielectric913can have a pattern corresponding to an intended aperture (e.g., aperture830ofFIG.8), which can have a circular shape (e.g., boundary C) from a top view. In some embodiments where a plurality of electrodes is included in a beam manipulator, the pattern of dielectric913can be more spoke-shaped. For example, as shown inFIG.4A, the spoke-shaped pattern of dielectric913can include not only boundary C but also the patterns, e.g., the radially outwardly extending shapes from the boundary C, corresponding to gaps431. In some embodiments, electrode layer910may further include a routing portion921. In some embodiments, routing portion921can be positioned adjacent to electrode contact portion911and outer to the electrode contact portion911with respect to the dielectric913.

In step B2, a first resist layer920is formed on electrode layer910. The first resist layer920may be a negative or positive resist According to embodiments, first resist layer920may include an opening921corresponding to an area of the dielectric913. Therefore, opening921in the first resist layer920can have a pattern corresponding to an intended aperture (e.g., aperture430ofFIG.4A), which can have a circular shape (e.g., boundary C) from a top view. In some embodiments where a plurality of electrodes are included in a beam manipulator, the pattern of opening920can include not only boundary C but also the patterns corresponding to gaps (e.g., gaps431ofFIG.4A), for example radially extending portions periodically distributed around the periphery of the substantially circular shape. In some embodiments, first resist layer920can be aligned to cover the electrode contact portions911from a top view.

In step B3, dielectric913and substrate900can be etched through the opening921in first resist layer920. In some embodiments, a hole932can be formed extending from an upper surface to a lower surface of the workpiece. For example, hole932can extend from an upper surface of electrode contact911to second surface902of the substrate900. In some embodiments, etching the substrate900can be performed separately from etching dielectric913while using first resist layer920as a mask. In some embodiments, substrate900can be etched after etching dielectric913. In some embodiments, etching substrate900can be performed by using material different from material used for etching dielectric913. Substrate900may be etched by DRIE (deep reactive ion etching) allowing high aspect ratio, RIE (reactive ion etching) such as plasma etching, etc. In some embodiments, substrate900can be etched by, but not limited to, a Bosch Process that is a high-aspect ratio plasma etching process. In step B3, first resist layer920may protect routing portion921or electrode portion911during the etching process. Step B3may include removing the first resist layer920. According to embodiments of the present disclosure, any gaps (e.g., gaps431ofFIG.4A) between adjacent electrodes as well as the intended aperture (e.g., aperture430ofFIG.4A) can be etched simultaneously at step B3because opening921of first resist layer920corresponds to an area of the dielectric913and the dielectric913can have a pattern corresponding to the aperture and gaps. Step B3may include removing the first resist layer920after the dielectric913and the substrate are etched.

In step B4, a second resist layer940can be formed on electrode layer910. The second resist layer940may be a negative or positive resist. In some embodiments, second resist layer940can cover routing portion921in order to protect the routing portion921during a subsequent step, i.e., step B5. In some embodiments, second resist layer940can have an opening941exposing at least part of electrode portion911. At step B4inFIG.9, second resist layer940is formed to cover routing portion9215and to expose electrode contact portion911or915as an example.

In step B5, a conductive layer970can be formed on an aperture facing surface of substrate900, which extends from first surface901to second surface902of the substrate900. In some embodiments, conductive layer970can be formed to constitute conductive layer811in beam manipulator800ofFIG.8upon completion of forming the beam manipulator800. In some embodiments, conductive layer970can be formed to contact with electrode contact portion911. In some embodiments, conductive layer970can be coated on a part of electrode contact portion911and an aperture facing surface of substrate900. In some embodiments, conductive layer970can be coated by sputtering conductive material from an upper side of the workpiece as indicated as arrows at step B5ofFIG.9. Conductive layer970can be also coated by evaporation deposition process, sputtering deposition, chemical vapor deposition, etc. At step B5, conductive material can be also deposited on the exposed upper surface and aperture facing surface of the electrode contact portion911while the aperture facing surface of the substrate900is coated by the deposited conductive material. In some embodiments, step B5may further include removing deposited conductive material on a base surface (e.g., base surface471ofFIG.4B) after depositing conductive layer970to enhance electric isolation between two adjacent electrodes. In some embodiments, step B5may further include treating the base surface to ensure that material is not deposited on the base surface before depositing a conductive layer970. In step B6, the second resist layer940can be removed. When the second resist layer940is removed, redundant conductive material deposited in step B5may be also removed.

As discussed above, it has been illustrated that even charge distribution through a body of a beam manipulator is implemented by coating conductive material on a non-conductive substrate. However, obtaining full conductive coating on a main body of a beam manipulator can be challenging in some scenarios:(1) Where an aperture has a high aspect ratio. Obtaining evenly deposited conductive material on a hole facing surface of a beam manipulator is challenging with some conductive material deposition techniques such as sputtering when the hole is narrow and deep. Some other conductive material deposition techniques such as ALD (atomic layer deposition) may not be cost effective;(2) Where a Bosch process is used for bulk etching of a silicon substrate. In this situation, scallops can be formed in the surface of the hole and this may cause shadow effects during conductive material deposition. Therefore, the area immediately behind each scallop from the conductive material deposition direction might not be covered; and(3) Where a beam manipulator includes multiple electrodes and electrodes should be electrically separated from each other. In this case, selective deposition of conductive material on electrodes is required while keeping multiple electrodes from electrically connected by the conductive material deposition. In order to enhance electrical disconnection between multiple electrodes, masks should be used when depositing conductive material or conductive material should be selectively removed after deposition.

The disclosure below illustrates that even charge distribution through a body of a beam manipulator is implemented without coating conductive material on a substrate. In some embodiments, a conductive substrate can be used as a body of a beam manipulator. In some embodiments, a highly doped silicon substrate can be used as a conductive substrate. Doping a substrate with a higher dose can lead to higher electric conductance and enable the substrate to behave similar to a metal. For example, when a silicon substrate is doped with dopant concentration of 1e21atoms/cm3, the substrate can have resistivity of 1e−6Ohm*m, which indicates electric conductivity equal to or even higher than a metal.

Reference is made toFIG.10Aillustrating a schematic plan view of an exemplary beam manipulator formed based on a conductive substrate, consistent with embodiments of the present disclosure.FIG.10Bis a schematic cross-sectional perspective view of the beam manipulator ofFIG.10A. As shown inFIG.10B, a beam manipulator1000may include a substrate1440and one or more electrodes1411. An aperture1430extending through two opposing surfaces of substrate1440is formed in the substrate1440. The two opposing surfaces of substrate1440can constitute major surfaces of substrate1440. The two opposing surfaces may include an upper surface1401and a lower surface1402of the substrate1440.

In some embodiments, one or more electrodes1411can be formed around aperture1430as shown in plan view inFIG.10A. In some embodiments, aperture1430can have a substantially circular shape (e.g., boundary C). The one or more electrodes1411extend radially outwardly from the aperture1430. For example, one or more electrodes1411can be positioned adjacent to aperture1430and can be positioned in upper surface1401of substrate1440. For example, each aperture facing surface of one or more electrodes1411can form a part of aperture1430. InFIG.10A, the aperture facing surface of the electrode1411is shown as a part of a rim defining the aperture1430in the upper surface of the substrate. In some embodiments, the one or more electrodes1411form a portion of upper surface1401. For example, the one or more electrodes1411may be positioned between aperture1430and a certain boundary (such as boundary B). In some embodiments, the certain boundary may surround the aperture1430. The certain boundary may be circular and the aperture1430substantially surrounded by the circular boundary may be substantially circular.

In various embodiments where beam manipulator1000has a plurality of electrodes, such as four electrodes as shown inFIG.10A, two adjacent electrodes among the plurality of electrodes1411may be spaced apart. Mutually facing surfaces of two adjacent electrodes may define a gap therebetween. For example, two facing surfaces of two adjacent electrodes1411may be spaced apart by a gap1431. In some embodiments, the facing surfaces defining gap1431may be parallel as shown inFIG.10A. In some other embodiments, the facing surfaces defining gap1431may radially diverging. The gap1431may have a consistent tangential dimension along its radial length. Here, a radial length of electrode1411can correspond to a radial distance between boundary B to boundary C. In some embodiments, a gap (such as gap1431) can have a radial length longer than a radial length of electrode1411to enhance electric disconnection between two adjacent electrodes1411. For example, a radial length of gap1431can correspond to a radial distance between a boundary B′ to boundary C. It will be noted that boundaries B, B′, and C are assumed to be continuous in that the gaps1431do interfere or even disrupt the boundaries B, B′, and C.

In some embodiments, gap1431can extend through substrate1440between upper surface1401and lower surface1402as shown inFIG.10B. Gap1431can extend through an entire length of the beam manipulator1000. Resulting from gap1431formed in substrate1440, substrate1440can have one or more protruding portions1451. Each of protruding portions1451comprises its respective electrode1411, such that the electrode portion1411provides at least one surface of the protruding portion1451, in plan view, radially inwardly protruding, for example, from boundary line B′. Each of the one or more protruding portions1451has two or more side surfaces facing gaps adjacent to the corresponding protruding portion. For example, protruding portion1451can have a first side surface1451S1and a second side surface1451S2that face opposite sides respectively. In some embodiments, a base surface1471can extend from an upper surface of beam manipulator400to lower surface402of substrate440. Base surface1471can be positioned radially outside of boundary B from the aperture1430or at boundary B. In some embodiments, protruding portions1451have aperture facing surfaces1451S3, each of which meets with first side surface1451S1and with second side surface1451S2. In some embodiments, each of the protruding portions1451extends from the upper surface1401to the lower surface402of the substrate440.

According to embodiments of the present disclosure, while beam manipulator1000is shown as having four electrodes1411inFIG.10AandFIG.10B, it is appreciated that beam manipulator1000can have any number of electrodes, for example, eight electrodes, ten electrodes, twelve electrode, and so on. In some embodiments. In some embodiments, beam manipulator can have a single electrode. A single electrode may have an annular, preferably ring, shaped surrounding aperture1430. In some embodiments, beam manipulator1000may not include a gap and aperture1430can be formed along boundary C and can extend from an upper surface of beam manipulator1000to lower surface402of substrate1440. In some other embodiments, beam manipulator1400may include a gap (e.g., gap1431) separating two ends of the same electrode.

According to embodiments, beam manipulator1000can further include an isolation layer1491in substrate1440such that each of protruding portions1451is electrically isolated from the rest of the substrate1440or the rest of the protruding portions. As shown inFIG.10B, each of protruding portions1451can include isolation layer1491extending from upper surface1401to lower surface1402of substrate1440and can be positioned between boundary B and boundary B′. In some embodiments, a radial length of gap1431can correspond to a radial length of electrode1411, which corresponds to a radial distance between boundary B to boundary C. In this example, isolation layer1491can be positioned radially outwardly from electrode1411. Isolation layer1491may have an annular, preferably ring, shape whose radial length corresponds to a radial distance between boundary B and boundary B′. In some embodiments, isolation layer1491can be made of electric insulation material. For example, oxide material can be used for forming isolation layer1491.

According to embodiments of the present disclosure, one or more beams can be manipulated by electric fields generated by beam manipulator1000. To generate electric fields to affect trajectories of one or more beams passing through aperture1430, one or more electrodes1411can be electrically connected via routing individually or collectively to a corresponding power source. The power source is generally positioned outside of an electron column of SEM. In some embodiments, an electric circuit configured to provide a driving voltage or control signal to one or more electrodes1411can be formed on the rest portion1420of the upper surface1401of substrate1440.

When a conductive substrate is used as a body of beam manipulator1000, for example, as illustrated inFIG.10AandFIG.10B, an additional conductive coating layer is not necessary to make aperture facing surface1451S3of the substrate1440conductive in that protruding portion1451of the substrate1440itself is conductive. Such a conductive protruding portion1451may form a constituent part of an elongate electrode. According to some embodiments of the present disclosure, a conductive coating layer can be applied to beam manipulator1000formed based on a conductive substrate. For example, when even higher conductance or more uniform charge distribution is required, conductive material can be coated on at least part of a conductive substrate. In these embodiments, defects (e.g., nonuniform deposition) of conductive material coating may have less impact on beam manipulation in that a substrate surface under the conductive coating material is also conductive.

Now reference is made toFIG.11Aillustrating a cross sectional view of exemplary configurations of abeam manipulator1100based on a highly doped silicon substrate1440, consistent with embodiments of the present disclosure.FIG.11Amay show a cross sectional view of a beam manipulator along an imaginary line A-A′ inFIG.10A. As shown inFIG.11A, beam manipulator1100can have substrate1440having upper surface1401and lower surface1402and aperture1430formed therein according to embodiments of the present disclosure. Aperture1430can extend between the upper surface1401and the lower surface1402of the substrate1440. In some embodiments, beam manipulator1100may have one or more electrodes1411around aperture1430and may be positioned on upper surface1401of substrate1440.

In some embodiments, two electrodes1411shown inFIG.11Amay be electrically separated from each other. For example, the two electrodes1411can constitute separate electrodes. In some embodiments, two electrodes1411shown inFIG.11Acan be part of a single electrode surrounding aperture1430. In some other embodiments, two electrodes1411shown inFIG.11Acan function as one electrode by electrically connecting the two electrodes1411.

As discussed with respect toFIG.10AandFIG.10B, beam manipulator1100can further comprise isolation layer1491formed in substrate1440. As shown inFIG.11A, isolation layer1491extends from upper surface1401to lower surface1402of substrate1440such that its corresponding protruding portion1451, i.e., elongated electrode, is electrically separated from a rest of the substrate1440.

In some embodiments, beam manipulator1100can further comprise a routing portion1421. For example, routing portion1421can be positioned on upper surface1401of substrate1440and adjacent to electrode1411. In some embodiments, protruding portion1451of substrate1440can have an electric potential different from corresponding electrode1411while operating. For example, protruding portion1451can be provided with a ground voltage. Here, the protruding portion1451can function as a shielding layer or shielding electrode. In some embodiments, each of protruding portions1451or1455can be provided with the same electric potential, which is different from an electric potential of corresponding electrode1411. In some embodiments, protruding portion1451can be connected to a power source via electric circuit placed in the routing portion1421.

In beam manipulator1100ofFIG.11A, substrate1440can form a main body of the beam manipulator1100and electrode1411can be at least part of an electrode of the beam manipulator1100. A main body can have a first surface and a second surface opposing to the first surface and an interconnecting surface extending between the first surface and the second surface and forming an aperture through the body according to embodiments of the present disclosure. A main body can comprise an elongated electrode that forms the interconnecting surface between the first surface and the second surface. In various embodiments including a beam manipulator (e.g., illustrated inFIG.11A), a protruding portion1451of a highly doped silicon substrate1440can be an elongated electrode included in the main body.

FIG.11Bis a cross section view of another exemplary configurations of a beam manipulator1100′ based on a highly doped silicon substrate, consistent with embodiments of the present disclosure. Beam manipulator1100′ has a similar configuration with beam manipulator1100shown inFIG.11Aexcept that beam manipulator1100′ does not comprise electrode1411. Instead, in beam manipulator1100′ shown in aFIG.11B, protruding portion1451′ (of substrate1440′) can function as an electrode. That is, protruding portion1451may function as an electrode because substrate1440′ is conductive. In some embodiments, a routing portion1421′ can be located on an upper surface1401′ of substrate1440′. For example, routing portion1421′ can cover both of corresponding protruding portion1451′ and the rest of the substrate1440′. In beam manipulator1100′, one or more protruding portions1451′ can function as electrodes of a beam manipulator and thus each of the protruding portions1451′ can be provided with its corresponding operating voltage. As discussed with respect toFIG.11A, each of the protruding portions1451′ can be electrically isolated from the rest of the protruding portions via isolation layer1491′.

FIG.12illustrates an exemplary method of forming beam manipulator1100ofFIG.11A, consistent with embodiments of the present disclosure. While a method of forming beam manipulator1100ofFIG.11Awill be explained, it will be appreciated that the present disclosure can be used for forming beam manipulator1100′ ofFIG.11Bexcept that an electrode layer1210does not include an electrode portion1211.

As shown inFIG.12, in step C1, a workpiece is provided. The workpiece can include a substrate1200and electrode layer1210. Electrode layer1210may be formed on an upper surface1201of the substrate1200. Substrate1200can be a highly doped silicon substrate. In some embodiments, electrode layer1210may include electrode portions1211spaced apart by a dielectric1213. According to embodiments, electrode portions1211can be formed to constitute electrodes1411in beam manipulator1100ofFIG.11Aupon completion of forming the beam manipulator. According to embodiments, dielectric1213can have a pattern corresponding to an intended aperture (e.g., aperture1430ofFIG.10A), which can have a substantially circular shape (e.g., boundary C) from a top view. In some embodiments where a plurality of electrodes1411are included in a beam manipulator, the pattern of dielectric1213can be more spoke-shaped. For example, as shown inFIG.10A, the spoke-shaped pattern of dielectric1213can include not only a substantially boundary C but also the patterns, e.g., the radially outwardly extending shapes from the boundary C, corresponding to gaps1431.

In some embodiments, electrode layer1210may further include a routing portion1221. In some embodiments, routing portion1221can be positioned adjacent to electrode portion1211and outer to the electrode portion1211with respect to the dielectric1213. For beam manipulator1100′ ofFIG.11B, electrode portion1211or1215can be replaced by routing portion1221.

In step C2, substrate1200can be etched. In some embodiments, a trench1231can be formed extending from lower surface1202to upper surface1201of substrate1200. Trench1231can be formed by, but not limited to, a Bosch Process. In some embodiments, trench1231can be part of an annularly, e.g., ring, shaped trench (e.g., between boundary B and boundary B′ ofFIG.10A.). In some embodiments, step C2may further include forming a mask (not shown) having a pattern of the trench1231on lower surface1202of substrate1200before etching the substrate1200. Step C2may further include removing the mask after etching the substrate1200. In some embodiments, etching can be performed from a lower surface side of substrate1200. Here, electrode layer1210can function as a stopping layer when etching the substrate1200.

In step C3, trench1231can be filled with electrical insulation material. In some embodiments, oxide material can be filled in the trench1231. Oxide material can be silicon oxide that is compatible with subsequent steps. In some embodiments, trench1231can be filled by a deposition process such as, but not limited to, CVD (chemical vapor deposition), PECVD (plasma-enhanced chemical vapor deposition), etc. Filling trench1231can be performed from a lower surface side of substrate1200. Step C3may further include removing insulation material deposited other than trench1231.

In step C4, dielectric1213and substrate1200can be etched so that a hole1230can be formed extending from an upper surface to a lower surface of the workpiece. Dielectric1213can be etched by a wet or dry etching process. Substrate1200may be etched by DRIE (deep reactive ion etching), RIE (reactive ion etching) such as plasma etching, etc. For example, hole1230can extend from an upper surface of electrode portion1211to lower surface1202of the substrate1200.

According to embodiments of the present disclosure, any gaps (e.g., gaps1431ofFIG.10A) between adjacent electrodes as well as the intended aperture (e.g., aperture1430ofFIG.10A) can be etched simultaneously at step C4. In some embodiments, etching the substrate1200can be performed separately from etching dielectric1213. In some embodiments, substrate1200can be etched after etching dielectric1213. In some embodiments, etching substrate1200can be performed by using material different from material used for etching dielectric1213. In some embodiments, substrate1200can be etched by, but not limited to, a Bosch Process that is a high-aspect ratio plasma etching process. While a resist layer is not shown inFIG.12, step C4can be performed after forming a resist layer (e.g., first resist layer920inFIG.9) having an opening corresponding to an area of dielectric1213. In some embodiments, the resist layer can be aligned to cover the electrode portion1211from a top view. The resist layer may be formed in any time during steps C1to C3and before step C4. The resist layer can comprise a first mask layer (e.g., of oxide material) and a second mask layer (e.g., silicon material). The first mask layer can be used to protect electrode layer1210during etching of dielectric1213and the second mask layer can be used to protect electrode layer1210during etching of substrate1200. In some embodiments, step C4may further include removing the resist layer after etching dielectric1213and substrate1200.

FIG.13a schematic plan view of an exemplary beam manipulator based on a doped silicon substrate and having a single electrode, consistent with embodiments of the present disclosure. As shown inFIG.13, a beam manipulator1300includes a single electrode1311that is electrically separated from the rest of the substrate1340by an isolation layer1390. In this example, the inner part inside boundary B of the substrate1340may function as an electrode and therefore additional electrode may not be included. Here, substrate1340can be a conductive substrate. In some embodiments, beam manipulator1300can correspond to beam manipulator1000,1100or1100′ shown inFIGS.10A,10B,11A, and11Bexcept that beam manipulator1300does not include a gap and beam manipulator1300include a single electrode.

FIG.14is a cross section view of a lens formed by a beam manipulator ofFIG.13. InFIG.14, one or more elements including a routing layer are omitted for simplicity. InFIG.14, a stacked beam manipulating device1400can comprise a first beam manipulator1300, a second beam manipulator1300′, and a third beam manipulator1300″, each of which can be beam manipulator1300ofFIG.13. A cross sectional view of beam manipulator1300inFIG.13is illustrated for each of first beam manipulator1300, second beam manipulator1300′, and third beam manipulator1300″ inFIG.14. InFIG.14, first beam manipulator1300can be positioned on top of second beam manipulator1300′ that is positioned on top of third beam manipulator1300″. In some embodiments, stacked beam manipulator1400can function as a lens such as an einzel lens by applying proper electric potentials to each of beam manipulators1300,1300′, and1300″. For example, a common potential, such as ground voltage, can be applied to first electrode1311of first beam manipulator1300and third electrode1311′ of third beam manipulator1300″. A different voltage (e.g., positive voltage) can be applied to second electrode1311′ of second beam manipulator1300′. The electrodes1311,1311′, and1311″ may define a respective through hole1330,1330′, and1330″ through the substrate of each manipulator1300,1300′, and1300′. In this example, an electric field is formed in a vertical direction inFIG.14, which is perpendicular to a plane parallel to a substrate surface while an horizontal electric field can be formed in a beam manipulator having multiple electrodes (e.g., beam manipulator inFIG.10AandFIG.10B). In this arrangement, the beam energy entering the first beam manipulator of the einzel lens and the beam energy leaving the third beam manipulator is the same. In another arrangement, that need not be the case, which may be achieved by having different potentials applied to the first and third manipulators or differing the geometries of the first and third manipulators (e.g., the diameters of the apertures in the first and third manipulators and/or the length of the first and third beam manipulators along the beam path). Further, although three manipulators are mentioned, any number of multiple beam manipulators may be used in the lens, such as two or more manipulators. According to embodiments of the present disclosure, beam energy (e.g., beam speed) of a beam passing through apertures1300,1300′ and1300″ as well as its angular direction relative to the multi-beam path direction can be manipulated.

In some embodiments, stacked beam manipulator1400can further include an insulation layer between first beam manipulator1300and second beam manipulator1300′ or between second beam manipulator1300′ and third beam manipulator1300″. In some embodiments, stacked beam manipulator1400may have a routing portion including circuits to provide electric power to first to third beam manipulators1300to1300″. In some embodiments, the routing portion can be provided with respect to first beam manipulator1300. For example, the routing portion1321can be positioned on top of substrate1300and second beam manipulator1300′ and third beam manipulator1300″ may not have their own routing portion with respect to them as shown inFIG.14. Such an arrangement may be beneficially applied to a deflector embodiment ofFIG.14. In a deflector embodiment, the electrodes1311,1311′, and1311″ may be a plurality of electrodes around the respective through hole1330,1330′, and1330″, e.g., as shown inFIGS.4A and4B. In such an embodiment, a manipulator is provided with a routing portion to control more than one of the manipulators, e.g., at least one adjoining manipulator. A manipulator (e.g.,1300′) without a routing portion may be at least in electrical contact with an adjoining manipulator (e.g.,1300) with a routing portion (e.g.,1321) or under control of a routing portion (e.g.,1321) associated with a manipulator (e.g.,1300) in electrical contact with the manipulator (e.g.,1300′) without a routing portion. Adjoining manipulators (e.g.,1300and1300′) may abut each other and may be in direct contact with each other, e.g., without an isolation layer between the electrodes1311and1311′ of the manipulators1300and1300′. Electrically contacting the electrodes (e.g.,1311and1311′) of adjoining deflector manipulators (e.g.,1300and1300′) enables a deflector manipulator with electrodes even longer than the thickness of the substrate body. For such a manipulator with a deflecting function: a greater deflection may be achieved at the same operating voltage of a manipulator of a single substrate thickness; same deflection can be achieved with a lower voltage than an operating voltage of a manipulator having a single substrate thickness; or a combination of both variations. At a lower operating voltage, the options available for controlling the electrodes are greater and the routing can be denser than at higher voltages. A lensing manipulator may have an extended electrode made from multiple adjoining substrates. For the lensing manipulator to have a lensing function, the lensing manipulator may require at least another beam manipulator with a routing portion; thereby providing two separate electrodes along the beam path.

WhileFIG.13andFIG.14are explained with a beam manipulator based on a doped silicon substrate as an exemplary usage of a beam manipulator with single electrode, it will be appreciated that a beam manipulator formed on a non-conductive substrate can be also used similarly as illustrated inFIG.13andFIG.14.

A non-transitory computer readable medium may be provided that stores instructions for a processor of a controller (e.g., controller50ofFIG.1) to control voltage levels, voltage polarities, voltage application timing, etc. for each electrode of the aforementioned beam manipulators. Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a Compact Disc Read Only Memory (CD-ROM), any other optical data storage medium, any physical medium with patterns of holes, a Random Access Memory (RAM), a Programmable Read Only Memory (PROM), and Erasable Programmable Read Only Memory (EPROM), a FLASH-EPROM or any other flash memory, Non-Volatile Random Access Memory (NVRAM), a cache, a register, any other memory chip or cartridge, and networked versions of the same.

It will be appreciated that the embodiments of the present disclosure are not limited to the exact construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof. The present disclosure has been described in connection with various embodiments, other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

The following clauses provided embodiments of the invention.

Clause 1: An electron beam manipulator for manipulating an electron beam in an electron projection system, the electron beam manipulator comprising: a body having a first surface and a second surface opposing to the first surface and an interconnecting surface extending between the first surface and the second surface and forming an aperture through the body, wherein the body comprises an electrode forming at least part of the interconnecting surface between the first surface and the second surface. Preferably the electrode extends between the first and second surfaces.

Clause 2: The electron beam manipulator of clause 1, wherein at least part of the electrode is associated with the aperture and is positioned on the first surface.

Clause 3: The electron beam manipulator of clause 2, wherein the electrode further forms at least part of the second surface.

Clause 4: The electron beam manipulator of clause 2 or 3, wherein the at least part of the electrode is configured to have an electric potential different from an electric potential of at least other part of the electrode when operating.

Clause 5: The electron beam manipulator of any of clauses 2 to 4 , wherein the at least part of the electrode is configured to have a uniform electric potential on the interconnecting surface between the first surface and the second surface when operating.

Clause 6: The electron beam manipulator of any preceding clause, wherein the body comprises: a substrate; and a first electric conductive layer formed on one surface of the substrate and forming at least part of the first surface of the body, wherein the electrode is connected with the first electric conductive layer.

Clause 7: The electron beam manipulator of clauses 2 to 5, wherein the body comprises: a substrate; and an electrode contact formed on the substrate, wherein the electrode contact is connected with the electrode.

Clause 8: The electron beam manipulator of any of clauses 2 to 7, wherein the electrode includes multiple electrodes.

Clause 9: The electron beam manipulator of clause 8, wherein two adjacent facing surfaces of adjacent electrodes of the multiple electrodes define a gap.

Clause 10: The electron beam manipulator of clauses 7 to 9, wherein the electrode includes multiple electrodes isolated from each other.

Clause 11: The electron beam manipulator of any preceding clause, wherein the body is formed by a doped silicon substrate forming the first surface, the second surface, and the electric conductor.

Clause 12: The electron beam manipulator of clause 11, wherein the body further includes an isolation layer extending between the first surface and the second surface and electrically isolating the electrode of the doped silicon substrate from the rest of the doped silicon substrate.

Clause 13: The electron beam manipulator of clause 12, wherein the isolation layer is formed by oxide material.

Clause 14: An electron beam manipulator device for manipulating an electron beam in an electron projection system, the electron beam manipulating device comprising: a first manipulator and a second manipulator, each of the first manipulator and the second manipulator comprising: a body having a first surface and a second surface opposing to the first surface and an interconnecting surface extending between the first surface and the second surface and forming an aperture through the body, wherein the body comprises an electrode forming at least part of the interconnecting surface between the first surface and the second surface, wherein at least part of the electrode is associated with the aperture and is positioned on the first surface, and wherein the first manipulator is positioned upstream of the second manipulator in a direction of the electron beam during operation.

Clause 15: The electron beam manipulator device of clause 14, wherein the electrode further forms at least part of the second surface of the first manipulator.

Clause 16: A method for manufacturing an electron beam manipulator, the method comprising: providing a workpiece comprising a substrate having a first surface and a second surface and an electrode layer formed relative to the first surface, the electrode layer having an electrode portion; forming a resist mask having an opening corresponding to a pattern on the workpiece, leaving an unmasked portion of the substrate; etching the unmasked portion of the substrate such that an inner wall is formed through the substrate to extend between the first surface and the second surface; removing the resist mask; and forming a first conductive layer coating the inner wall of the substrate.

Clause 17: The method of clause 16, further comprising etching the electrode layer such that the electrode portion includes multiple electrode portions, wherein adjacent electrode portions of the multiple electrode portions are separated via a gap formed by the etching.

Clause 18: The method of clause 16 or 17, wherein etching the substrate is performed by using the electrode layer as a stopper.

Clause 19: The method of clause 18, further comprising: forming a routing resist mask covering a routing portion formed within the electrode layer; etching the dielectric material; and removing the routing resist mask.

Clause 20: The method of any one of clauses 16-19, wherein the resist mask is removed from the second surface and wherein forming a first conductive layer comprises: forming the first conductive layer covering the inner wall and the second surface by depositing electric conductive material from a side of the second surface.

Clause 21: The method of any one of clauses 16-20, wherein the workpiece further comprises a second conductive layer positioned between the electrode layer and the first surface and having a corresponding pattern to the pattern, and wherein forming the first conductive layer is performed to connect the first conductive layer with the second conductive layer.

Clause 22: The method of clause 16 or 17, wherein forming a resist mask is performed to form the resist mask on the electrode layer.

Clause 23: The method of clause 22, further comprising etching dielectric material filling the pattern in the electrode layer before etching the substrate.

Clause 24: The method of any one of clauses 16, 17, 22, or 23, further comprising: forming a routing resist mask covering a routing portion formed within the electrode layer before forming the first conductive layer; and removing the routing resist mask after forming the first conductive layer.

Clause 25: The method of any one of clauses 22-24, wherein forming the first conductive layer comprising: forming the first conductive layer covering the inner wall of the substrate and the electrode portion by depositing electric conductive material from a side of the first surface.

Clause 26: The method of clause 17, wherein forming the first conductive layer comprising: forming the first conductive layer to include a first part corresponding to a first electrode portion of the multiple electrode portions and a second part corresponding to a second electrode portion of the multiple electrode portions.

Clause 27: A method for manufacturing an electron beam manipulator, the method comprising: providing a workpiece comprising a conductive substrate having a first surface and a second surface; forming an isolation layer extending between the first surface and the second surface and electrically isolating a first substrate portion from a second substrate portion, the first substrate portion being positioned radially inward from the second substrate portion; and etching a part of the first substrate portion such that an inner wall extends through the substrate between the first surface and the second surface, the inner wall providing at least an electrode surface.

Clause 28: The method of clause 27, wherein forming an isolation layer includes: etching the substrate and filling the etched portion with oxide material.

Clause 29: The method of clause 27 or 28, wherein etching the first substrate portion further includes etching the first substrate portion such that gaps extend outward from the inner wall, electrode surfaces at least in part defining the facing surfaces of the gaps.

Clause 30: The method of any one of clauses 26-29, further comprising etching an electrode layer comprised in the workpiece such that an electrode layer includes multiple electrode portions, wherein adjacent electrode portions of the multiple electrode portions are separated via a gap formed by the etching.

Clause 31: An electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool, the charged particle beam manipulator comprising:

a substrate having opposing major surfaces and through opening providing an interconnecting surface extending between the major surfaces, wherein at least part of the interconnecting surface is defined by one or more electrodes.

Clause 32: The electron beam manipulator of clause 31, wherein the one or more electrodes comprise metal.

Clause 33: The electron beam manipulator of clause 31 or 32, wherein the one or more electrodes extend between the major surfaces.

Clause 34: The electron beam manipulator of any of clauses 31 to 33, wherein the one or more electrodes are configured to provide an even charge distribution there over.

Clause 35: The electron beam manipulator of any of clause 31 to 34, wherein the one or more electrodes comprise an electrically conductive coating.

Clause 36: An electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool, the charged particle beam manipulator comprising: a substrate having opposing major surfaces and an electrode, wherein the electrode forms at least part of a surface of an interconnecting-through-hole extending between the major surfaces, the through-hole forming an opening in each of the major surfaces, and wherein the electrode forms at least part of one of the two major surfaces surrounding one of the openings.

Clause 37: An electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool, the charged particle beam manipulator comprising: a substrate having opposing major surfaces and a through-passage providing an interconnecting surface extending between the major surfaces, wherein at least part of the interconnecting surface is formed by an electrode configured in use to be held at a potential difference.

Clause 38: The electron beam manipulator of clause 37, wherein the through passage comprises parts of differing cross-sectional area comprising a part having smaller cross-sectional area positioned upstream of the electrode in a path of the electron beam.

Clause 39: The electron beam manipulator of clause 37 or 38, wherein an electrode shield is configured to be upstream of the electrode in a path of the electron beam.

Clause 40: The electron beam manipulator of any of clauses 37 to 39, wherein at least part of the electrode is positioned on one of the major surfaces, and wherein the through passage comprises a shield that is configured to shield the at least part of the electrode.

Clause 41: The electron beam manipulator of any of clauses 37 to 40, wherein at least part of the electrode is positioned on one of the major surfaces, and wherein a part of the passage is configured to shield the at least part of the electrode with respect to a path of the electron beam through the through passage.

Clause 42: An electron beam manipulator configured to manipulate an electron beam in a projection system of an electron beam tool, the charged particle beam manipulator comprising: a substrate body having: opposing major surfaces; and a through-passage having an interconnecting surface extending between the major surfaces, wherein at least part of the interconnecting surface is recessed: between adjoining edges of at least one electrode; and into the substrate body deeper than the thickness of the at least one electrode.

Clause 43: The electron beam manipulator of clause 42, wherein the at least one electrode is made of doped silicon.