Scanning type electron microscopy system

Abstract

To prevent occurrence of deflection aberration in an electron beam to be collected and analyzed with a deflector group.SOLUTION: A scanning type electron microscopy (SEM) system includes a plurality of electron beam sources configured to generate primary electron beams, and an electron optical column array with a plurality of electro-optical columns. The electro-optical column has an electro-optical element. The electro-optical element includes a deflector layer configured to be driven by a common controller shared by at least some of the electro-optical columns, and includes a trim deflector layer configured to be driven by an individual controller. The electro-optical elements are arranged to form an electron beam channel, and the electron beam channel is configured to direct a primary electron beam onto a specimen fixed on a stage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates generally to wafer and photomask / reticle characterization and preparation, and more specifically to array-based characterization tools. [Background technology]

[0002] In the manufacture of semiconductor devices, such as logic and memory devices, the various features and layers of the semiconductor devices are typically formed by processing the semiconductor devices using multiple semiconductor fabrication and metrology processes. In a leading manufacturing process, features are printed onto the semiconductor device, such as a wafer, using a photomask / reticle. As semiconductor devices become smaller and smaller laterally and larger vertically, it becomes imperative to develop enhanced inspection and review equipment and procedures to increase the sensitivity and throughput of the photomask / reticle and wafer inspection processes.

[0003] One characterization technology is electron beam based characterization, e.g., scanning electron microscopy (SEM). In some SEMs, scanning electron microscopy is performed through secondary electron beam collection (e.g., secondary electron (SE) imaging systems). In some SEMs, scanning electron microscopy is performed by splitting a single electron beam into multiple beams and using a single electron optical column to individually tune and scan the multiple beams (e.g., multi-beam SEM systems). In some SEMs, scanning electron microscopy is performed by an SEM system with multiple electron optical columns (e.g., multi-column SEM systems).

[0004] In an SEM system, a specimen can be imaged through collection and analysis of an electron beam that includes electrons emitted and / or backscattered from the specimen while a primary electron beam is scanned across the specimen. A set of deflectors are used to deflect (e.g., focus or steer) the electron beam toward the specimen and then back toward a detector in the electron optical column of the SEM system. The use of these deflectors can introduce deflection aberrations into the electron beam that is collected and analyzed. Non-uniformities in the deflection field can cause such deflection aberrations. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2002 / 0117967 Summary of the Invention [Problem to be solved by the invention]

[0006] It would therefore be advantageous to provide a system and method that eliminates the above-mentioned shortcomings. [Means for solving the problem]

[0007] In accordance with one or more embodiments of the present disclosure, a scanning electron microscopy (SEM) system is disclosed. In some embodiments, the SEM system includes a plurality of electron beam sources. In some embodiments, at least some of the electron beam sources are configured to generate a primary electron beam. In some embodiments, the SEM system includes an electron optical column array with a plurality of electron optical columns. In some embodiments, an electron optical column of the plurality of electron optical columns includes a plurality of electron optical elements. In some embodiments, the plurality of electron optical elements includes a deflector layer. In some embodiments, the deflector layer includes an upper deflector configured to receive a first voltage and a lower deflector configured to receive an additional voltage. In some embodiments, the deflector layer is configured to be driven by a common controller shared by at least some of the plurality of electron optical columns. In some embodiments, the plurality of electron optical elements includes a trim deflector layer. In one embodiment, the trim deflector layer includes an upper trim deflector configured to receive a first trim voltage and a lower trim deflector configured to receive an additional trim voltage. In one embodiment, the trim deflector layer is configured to be driven by an individual controller. In one embodiment, the plurality of electron optical elements are arranged to form an electron beam channel. In one embodiment, the electron beam channel is configured to direct a primary electron beam to a specimen held on a stage. In one embodiment, the specimen emits an electron beam in response to the primary electron beam. In one embodiment, the electron optical column includes at least one electron detector. In one embodiment, the electron beam channel is configured to direct the electron beam to the at least one electron detector.

[0008] In accordance with one or more embodiments of the present disclosure, an electro-optical system is disclosed. In some embodiments, the electro-optical system includes an electro-optical column array. In some embodiments, the electro-optical column array includes a plurality of electro-optical columns. In some embodiments, an electro-optical column of the plurality of electro-optical columns includes a plurality of electro-optical elements. In some embodiments, the plurality of electro-optical elements includes a deflector layer. In some embodiments, the deflector layer includes an upper deflector configured to receive a first voltage and a lower deflector configured to receive an additional voltage. In some embodiments, the deflector layer is configured to be driven by a common controller shared by at least some of the plurality of electro-optical columns. In some embodiments, the plurality of electro-optical elements includes a trim deflector layer. In some embodiments, the trim deflector layer includes an upper trim deflector configured to receive a first trim voltage and a lower trim deflector configured to receive an additional trim voltage. In one embodiment, the trim deflector layer is configured to be driven by an individual controller. In one embodiment, the plurality of electron optical elements are arranged to form an electron beam channel. In one embodiment, the electron beam channel is configured to direct a primary electron beam to a specimen held on a stage. In one embodiment, the specimen emits an electron beam in response to the primary electron beam. In one embodiment, the electron optical column includes at least one electron detector. In one embodiment, the electron beam channel is configured to direct the electron beam to the at least one electron detector.

[0009] In accordance with one or more embodiments of the present disclosure, a scanning electron microscopy (SEM) system is disclosed. In some embodiments, the SEM system includes a plurality of electron beam sources. In some embodiments, at least some of the electron beam sources are configured to generate a primary electron beam. In some embodiments, the SEM system includes an electron optical column array with a plurality of electron optical columns. In some embodiments, at least some of the electron optical columns include a plurality of electron optical elements. In some embodiments, the plurality of electron optical elements are arranged to form a cone-shaped electron beam channel. In some embodiments, the cone-shaped electron beam channel is configured to direct the primary electron beam to a specimen secured on a stage. In some embodiments, the specimen emits an electron beam in response to the primary electron beam. In some embodiments, at least some of the electron optical columns include at least one electron detector. In some embodiments, the cone-shaped electron beam channel is configured to direct the electron beam to the at least one electron detector.

[0010] In accordance with one or more embodiments of the present disclosure, an electron optical system is disclosed. In some embodiments, the electron optical system includes an electron optical column array. In some embodiments, the electron optical column array includes a plurality of electron optical columns. In some embodiments, an electron optical column of the plurality of electron optical columns includes a plurality of electron optical elements. In some embodiments, the plurality of electron optical elements are arranged to form a cone-shaped electron beam channel. In some embodiments, the cone-shaped electron beam channel is configured to direct a primary electron beam to a specimen secured on a stage. In some embodiments, the specimen emits an electron beam in response to the primary electron beam. In some embodiments, the electron optical column includes at least one electron detector. In some embodiments, the cone-shaped electron beam channel is configured to direct the electron beam to the at least one electron detector.

[0011] A characterization system is disclosed in accordance with one or more embodiments of the present disclosure. In some embodiments, the characterization system includes a plurality of radiation sources. In some embodiments, at least some of the radiation sources are configured to generate a primary radiation beam. In some embodiments, the characterization system includes a column array. In some embodiments, the column array includes a plurality of columns. In some embodiments, a column of the plurality of columns includes a plurality of elements. In some embodiments, the plurality of elements includes a deflector layer configured to receive a voltage. In some embodiments, the deflector layer is configured to be driven by a common controller shared by at least some of the plurality of columns. In some embodiments, the plurality of elements includes a trim deflector layer configured to receive a trim voltage. In some embodiments, the trim deflector layer is configured to be driven by an individual controller. In some embodiments, the plurality of elements are arranged to form a beam channel. In some embodiments, the beam channel is configured to direct the primary radiation beam to a specimen secured on a stage. In some embodiments, the sample generates a radiation beam in response to the primary radiation beam, in some embodiments, the column includes at least one detector, and in some embodiments, the beam channel is configured to direct the radiation beam generated by the sample to the at least one detector.

[0012] Those skilled in the art will be able to better appreciate the many advantages of the present disclosure by referring to the accompanying drawings, in which: [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic block diagram of a Scanning Electron Microscopy (SEM)-based characterization tool according to one or more embodiments of the present disclosure. [Diagram 2]FIG. 1 is a simplified schematic diagram of an electron optical column in a SEM-based characterization tool according to one or more embodiments of the present disclosure. [Diagram 3] FIG. 1 is a schematic block diagram of an optical characterization tool according to one or more embodiments of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of a characterization system having a characterization tool and a controller in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Reference will now be made in detail to the disclosed subject matter, which is illustrated in the accompanying drawings.

[0015] 1-4 collectively, an array-based characterization tool according to one or more embodiments of the present disclosure is disclosed.

[0016] Embodiments of the present disclosure are directed to providing an SEM-based characterization tool in which a common mode voltage (e.g., common to the electron optical columns in the electron optical column array) is applied to a set of deflectors in the electron optical columns in an electron optical column array. It is noted that the characterization tool of the present disclosure may be configured as any imaging-based characterization tool known in the art, including, but not limited to, an inspection tool, a review tool, an imaging-based overlay metrology tool, etc.

[0017] Embodiments of the present disclosure are also directed to providing an SEM-based characterization tool that applies a voltage to an additional set of deflectors in each electron optical column in an electron optical column array substantially simultaneously with the application of a common mode voltage to the set of deflectors, the additional voltage being dynamic and unique to each electron optical column. It is noted that generating a voltage driver capable of providing a common mode voltage that can simultaneously provide a unique, highly accurate, dynamic voltage to each electron optical column is not feasible with SEM-based characterization tools known in the art and is believed to be impractical and difficult.

[0018] Embodiments of the present disclosure are also directed to reducing the number, complexity, volume and power consumption of electronic components in a SEM-based characterization tool.Embodiments of the present disclosure are also directed to improving secondary electron capture rates in SEM-based characterization tools.Embodiments of the present disclosure are also directed to reducing deflection aberrations and increasing deflection field uniformity of deflectors in SEM-based characterization tools.

[0019] The embodiments of the present disclosure are directed to providing a characterization tool in which a common mode static and / or dynamic voltage (e.g., common to the columns in the column array) is applied to a set of deflectors in the columns in the column array. The embodiments of the present disclosure are also directed to providing a characterization tool that applies a voltage to an additional set of deflectors in each column in the column array substantially simultaneously with the application of the common mode voltage to the set of deflectors, the additional voltage being static and / or dynamic and unique to each column. The embodiments of the present disclosure are also directed to reducing the number, complexity, volume, and power consumption of components in the characterization tool. The embodiments of the present disclosure are also directed to improving the capture rate in the characterization tool. The embodiments of the present disclosure are also directed to reducing deflection aberrations and increasing deflection field uniformity of deflectors in the characterization tool.

[0020] 1 and 2, a scanning electron microscopy (SEM) based characterization tool 100 according to one or more embodiments of the present disclosure is depicted generally.

[0021] 1 depicts a simplified schematic depiction of a SEM-based characterization tool 100 according to one or more embodiments of the present disclosure. According to an embodiment, the SEM-based characterization tool 100 includes an electron beam source array 102. According to an embodiment, the electron beam source array 102 includes one or more electron beam sources. For example, the electron beam source array 102 may include, but is not limited to, a first electron beam source 104a, a second electron beam source 104b, a third electron beam source 104c, and / or at least a fourth electron beam source 104d. According to an embodiment, the one or more electron beam sources include an electron beam emitter or electron gun.

[0022] In addition, the SEM-based characterization tool 100 according to the embodiment includes an electron optical column array 108. Moreover, in the embodiment, the electron optical column array 108 includes one or more electron optical columns. For example, the electron optical column array 108 can include, but is not limited to, a first electron optical column 110a, a second electron optical column 110b, a third electron optical column 110c, and / or at least a fourth electron optical column 110d.

[0023] Additionally, in embodiments, one or more primary electron beams are generated by one or more electron beam sources. For example, primary electron beams 106a, 106b, 106c, 106d can be generated by electron beam sources 104a, 104b, 104c, 104d. Additionally, in embodiments, one or more primary electron beams are directed (e.g., focused or steered) to one or more electron optical columns in the electron optical column array 108. For example, primary electron beams 106a, 106b, 106c, 106d can be directed to electron optical columns 110a, 110b, 110c, 110d in the electron optical column array 108. In some embodiments, one or more source-side electron optical elements in the electron beam source array 102 split the electron beams generated by one or more electron beam sources and direct them to two or more electron optical columns in the electron optical column array 108.

[0024] In some embodiments, one or more of the electron optical columns may include one or more electron optical elements. For example, the electron optical columns 110a, 110b, 110c, 110d may include the electron optical elements 112a, 112b, 112c, 112d. In other examples, the one or more electron optical elements may include, but are not limited to, one or more electrostatic lenses, one or more electromagnetic lenses, etc.

[0025] In an embodiment, one or more primary electron beams are directed by one or more electron optical columns to a specimen 114 held on a specimen stage 116. For example, primary electron beams 106a, 106b, 106c, 106d may be directed by electron optical columns 110a, 110b, 110c, 110d to a specimen 114 held on a specimen stage 116. In an embodiment, one or more secondary electron beams may be emitted and / or backscattered by the specimen 114 as the one or more primary electron beams impinge on the specimen 114. For example, secondary electron beams 118a, 118b, 118c, 118d may be emitted and / or backscattered by the specimen 114 as the primary electron beams 106a, 106b, 106c, 106d impinge on the specimen 114. As an example, secondary electrons may be emitted from the specimen 114 in response to the primary electron beams 106a, 106b, 106c, and 106d. In addition, electrons from the primary electron beams 106a, 106b, 106c, and 106d may be backscattered by the specimen 114.

[0026] It is noted that because the secondary electron beams 118a, 118b, 118c, 118d are wider than the primary electron beams 106a, 106b, 106c, 106d, the electrons in the secondary electron beams 118a, 118b, 118c, 118d will be slower than the electrons in the primary electron beams 106a, 106b, 106c, 106d. In addition, it is noted that because energy equivalent to the landing energy may be lost by the electrons in the primary electron beams 106a, 106b, 106c, 106d when the secondary electron beams 118a, 118b, 118c, 118d are formed by emission and / or backscattering, the electrons in the secondary electron beams 118a, 118b, 118c, 118d will be slower than the electrons in the primary electron beams 106a, 106b, 106c, 106d.

[0027] The specimen 114 may include any specimen suitable for inspection and / or review. For example, but not limited to, the specimen 114 may include a photomask / reticle, a semiconductor wafer, etc. The term "wafer" in this disclosure refers to a substrate formed of semiconductor and / or non-semiconductor materials. For example, in the case of semiconductor materials, the wafer may be formed of, but not limited to, monocrystalline silicon, gallium arsenide, and / or indium phosphide. Thus, the terms "wafer" and "specimen" may be used interchangeably in this disclosure. Therefore, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure. It is noted that a wide variety of devices may be formed on a wafer, and the term wafer in this application is intended to encompass a wafer having any type of device formed thereon as known in the art. Thus, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0028] The specimen stage 116 may include any suitable mechanical and / or robotic assembly known in the art of electron beam microscopy. In an embodiment, the specimen stage 116 is a drivable stage. For example, the specimen stage 116 may include one or more translation stages adapted to selectively translate the specimen 114 along one or more linear directions (e.g., x-direction, y-direction, and / or z-direction). In another embodiment, the specimen stage 116 may include one or more rotation stages adapted to selectively rotate the specimen 114 along a rotation direction, but is not limited to such. In another embodiment, the specimen stage 116 may include rotation stages and translation stages adapted to selectively translate the specimen 114 along a linear direction and / or rotate the specimen 114 along a rotation direction. According to another example, the specimen stage 116 can be configured to translate or rotate the specimen 114 for positioning, focusing, and / or scanning according to a selected inspection or metrology algorithm, including any known in the art.

[0029] FIG. 2 depicts a simplified schematic representation of an electron optical column 110a included in a SEM-based characterization tool 100 according to one or more embodiments of the present disclosure.

[0030] Although embodiments of the present disclosure are directed to impinging one or more primary electron beams 106a on the surface of the specimen 114 to generate one or more secondary electron beams 118a, it is noted that one or more primary electron beams 106a have been omitted from FIG. 2 for clarity. It is noted, however, that one or more primary electron beams 106a can be directed at the specimen 114 and done in a manner that does not affect the collection of one or more secondary electron beams 118a traveling in the opposite direction within the electron optical column 110a. Thus, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0031] It is noted that all descriptions of primary electron beam 106a may be extended to primary electron beams 106b, 106c, and 106d for purposes of this disclosure. Additionally, it is noted that all descriptions of electron optical column 110a may be extended to electron optical columns 110b, 110c, and 110d for purposes of this disclosure. It is further noted that all descriptions of electron optical element 112a may be extended to electron optical elements 112b, 112c, and 112d for purposes of this disclosure. It is further noted that all descriptions of secondary electron beam 118a may be extended to secondary electron beams 118b, 118c, and 118d for purposes of this disclosure. Thus, the above descriptions should be taken as merely illustrative and not as limitations on the scope of the present disclosure.

[0032] In an embodiment, the electron optical column 110a includes one or more detectors 200 configured to detect one or more secondary electron beams 118a from the specimen 114. For example, the one or more detectors 200 may include, but are not limited to, one or more secondary electron detectors. In another example, the one or more detectors 200 may include, but are not limited to, one or more backscattered electron detectors. For simplicity, the remainder of this disclosure discusses various embodiments of the present disclosure in the context of secondary electron detection. However, it is recognized herein that the electron optical column 110a may be configured for secondary electron detection from the specimen 114 and / or for backscattered electron detection. Thus, the scope of the present disclosure should not be construed as being limited to detection of secondary electrons, but should be considered to encompass detection of secondary electrons and / or backscattered electrons.

[0033] In addition, in the embodiment, one or more of the electron-optical elements 112a have a deflector stack, in which one or more deflectors are incorporated. For example, the deflector can be an octupole deflector (e.g., having eight plates), a quadrupole deflector (e.g., having four plates), etc. In addition, the deflector stack in the embodiment has one or more deflection layers, in which one or more deflectors are incorporated. For example, one or more pairs of deflectors can be incorporated in the deflection layers. As an example, one or more pairs of octupole deflectors, one or more pairs of quadrupole deflectors, or a combination of one or more pairs of octupole deflectors and one or more pairs of quadrupole deflectors can be incorporated in the deflection layers. In the embodiment, the deflection ratio of the deflection layers can be used to quantify the deflection aberration associated with the deflector pairs.

[0034] In addition, the electron-optical column 110a in the embodiment has one or more voltage lines corresponding to the number of deflectors in the electron-optical column 110a. For example, if the one or more electron-optical elements 112a include four octupole deflectors, the electron-optical column 110a has 32 voltage lines for the four octupole deflectors. In addition, in the embodiment, the deflectors in the one or more electron-optical elements 112a form a deflector pair or deflection layer depending on the operating voltage.

[0035] In addition, the embodiment includes an upper deflector 202 and a lower deflector 204 in the deflection layer. In addition, the upper deflector 202 and the lower deflector 204 in the embodiment are configured to perform one or more of two-stage deflection and / or dynamic astigmatism correction. In addition, the upper deflector 202 and the lower deflector 204 in the embodiment have a selected thickness, i.e., a thickness that allows two-stage deflection while applying the same voltage to the upper deflector 202 and the lower deflector 204. For example, if the upper deflector 202 and the lower deflector 204 are octupole deflectors, 16 voltage lines would be required. It is noted that a pair of deflectors including the upper deflector 202 and the lower deflector 204 can be considered a deflector layer for purposes of this disclosure.

[0036] Also within the deflection layer, in an embodiment, are upper trim deflectors 206 and lower trim deflectors 208. Further, in an embodiment, the upper trim deflectors 206 and lower trim deflectors 208 are configured to perform one or more of static deflection, static astigmatism correction, dynamic deflection, and / or dynamic astigmatism correction. It is noted that the deflector layer within which the upper trim deflectors 206 and lower trim deflectors 208 reside can be considered a trim deflector layer for purposes of this disclosure.

[0037] Additionally, in an embodiment, the upper deflector 202 is coupled to one or more amplifiers 210. Additionally, in an embodiment, the lower deflector 204 is coupled to one or more amplifiers 212. Additionally, in an embodiment, the upper trim deflector 206 is coupled to one or more amplifiers 214. Additionally, in an embodiment, the lower trim deflector 208 is coupled to one or more amplifiers 216.

[0038] For example, the deflector layers and trim deflector layers can be designed to produce deflections that exceed the individual capabilities of the deflectors 202, 204, 206, 208 and their corresponding amplifiers 210, 212, 214, 216. In this manner, multiple deflection layers can be stacked to combine deflections and increase the amount of deflection achievable by one or more electro-optical elements 112a in the electro-optical column 110a. Thus, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0039] According to another example, the deflector layer containing the upper and lower deflectors 202 and 204 can be operated at a high voltage and the trim deflector layer containing the upper and lower trim deflectors 206 and 208 can be operated at a low voltage. In this example, the upper and lower deflectors 202 and 204 can be considered a high voltage deflector pair for purposes of this disclosure. Additionally, in this example, the upper and lower trim deflectors 206 and 208 can be considered a low voltage deflector pair for purposes of this disclosure. It is noted, however, that the trim deflector layer containing the upper and lower trim deflectors 206 and 208 can be operated at a voltage equal to or higher than the voltage of the deflector layer containing the upper and lower deflectors 202 and 204. Therefore, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0040] 1 and 2, in an embodiment in which the electron optical column array 108 includes electron optical columns 110a, 110b, 110c, and 110d, splitting the voltage for the high and low deflectors allows for a reduction in electrical components in the electron optical column array 108. For example, if the top deflector 202 is an octupole deflector, the per-plate signals of the top deflector 202 in the electron optical column 110a can be utilized and / or driven by one common controller or common amplifier 210, and thus, a total of eight amplifiers 210 or common controllers can be coupled to each of the top deflectors 202 in the electron optical columns 110b, 110c, and 110d. As another example, if the lower deflector 204 is an octupole deflector, the plate-by-plate signals of the lower deflectors 204 in one or more electron optical columns 110a can be utilized and / or driven by one common controller or common amplifier 212, thus resulting in a total of eight amplifiers 212 or common controllers being coupled to each of the lower deflectors 204 of the electron optical columns 110b, 110c, and 110d.

[0041] It is noted that the use of common amplifiers for each individual deflector plate of the upper and lower deflectors 202 and 204 is possible due to the non-common static configuration and / or the division of a portion of the dynamic deflection into the trim deflector layers. For example, each plate of the upper trim deflector 206 can be individually driven and / or adjusted by a controller or amplifier 214, so that the number of controllers or amplifiers 214 in the electron optical columns 110a, 110b, 110c, 110d is up to the number of plates in the upper trim deflector 206. In another example, each plate of the lower trim deflector 208 can be individually driven and / or adjusted by a controller or amplifier 216, so that the number of controllers or amplifiers 216 in the electron optical columns 110a, 110b, 110c, 110d is up to the number of plates in the lower trim deflector 208.

[0042] In addition, it is noted that the amplifiers 210, 212 and corresponding connectors coupled to the upper and lower deflectors 202, 204, respectively, may be larger (e.g., due to higher operating voltages) than the amplifiers 214, 216 and corresponding connectors coupled to the upper and lower trim deflectors 206, 208, respectively. In addition, it is noted that the smaller amplifiers 214, 216 may be more tightly routed, cabled and / or packaged and consume less power than the larger amplifiers 210, 212.

[0043] In this regard, one or more amplifiers 210 or a common controller coupled to the upper and lower deflectors 202 and 204, respectively, may operate as a common driver for the deflector layer in which the upper and lower deflectors 202 and 204 reside across one or more electron-optical columns 110a, 110b, 110c, and 110d reside in the electron-optical column array 108. In addition, one or more amplifiers 214 or a controller coupled to the upper and lower trim deflectors 206 and 208, respectively, may operate as smaller individual drivers for the trim deflector layer in which the upper and lower trim deflectors 206 and 208 reside for the purpose of finely adjusting the secondary electron beam(s) 118a, 118b, 118c, and 118d reside. Thus, the overall volume, complexity and power consumption of the present SEM-based characterization tool 100 may be reduced.

[0044] Although the embodiments of the present disclosure are directed to coupling the upper and lower deflectors 202 and 204 to the amplifiers 210 and 212, respectively, it is noted that the upper and lower deflectors 202 and 204 may be coupled to a single common set of amplifiers, in which case the upper and lower deflectors 202 and 204 may be commonly coupled across the electron optical columns 110a, 110b, 110c, and 110d. Thus, the above description should be taken as merely illustrative, and not as a limitation on the scope of the present disclosure.

[0045] 2, in an embodiment, the deflector layers and trim deflector layers are arranged to define an electron beam channel having a selected shape and centered on an axis passing through one or more electron optical elements 112a of the electron optical column 110a. For example, the shape of the electron beam channel may be selected to improve (e.g., increase and / or maximize) the deflection sensitivity of the electron optical column 110a without affecting (e.g., decreasing and / or reducing) the collection of the or other secondary electron beams 118a. For example, the shape may be selected as part of the deflection sensitivity improvement to direct one or more secondary electron beams 118a back through the electron beam channel as close as possible to one or more electron optical elements 112a without colliding with the one or more electron optical elements 112a. It is noted that improving the deflection sensitivity of the electron optical column 110a without affecting the collection of the secondary electron beam 118a is important for a low voltage deflector pair.

[0046] In another example, the electron beam channel may be conical with a narrow end and a wide end, and the conical electron beam channel may be formed via one or more design constraints on one or more electron optical elements 112a in the electron optical column 110a.

[0047] For example, the conical electron beam channel may be formed by a conical aperture in one or more of the electron optical elements 112a. The conical aperture may be defined by an inner surface of the one or more of the electron optical elements 112a, in particular an inner surface that is tilted / graded with respect to an angle from a central axis passing through the one or more of the electron optical elements 112a. One or more of the upper deflector 202, the lower deflector 204, the upper trim deflector 206, and / or the lower trim deflector 208 may have a tilted / graded inner surface.

[0048] Additionally, the conical electron beam channel may be formed by an inner surface of the first electron optical element 112a and an inner surface of the at least one additional electron optical element 112a. The inner surfaces of the first electron optical element 112a and the at least one additional electron optical element 112a may each be located at a selected distance (e.g., different selected distances or the same selected distance) from a central axis passing through the electron optical elements 112a. One or more of the upper deflector 202, the lower deflector 204, the upper trim deflector 206, and / or the lower trim deflector 208 may have an inner surface located at a selected distance from its central axis.

[0049] Further, the conical electron beam channel can be formed by the combination of conical openings in the electron optical elements 112a and by the inner surfaces of the first electron optical element 112a and at least one additional electron optical element 112a located at a selected distance from the central axis.

[0050] In another embodiment, the shape of the electron beam channel can be tailored to accommodate the components of the SEM-based characterization tool 100. For example, the narrow end of the channel can be tailored to the size of the secondary electron beam(s) 118a. Additionally, the wide end of the channel can be tailored to the size of the secondary electron detector(s) 200.

[0051] Additionally, in embodiments, the upper deflector 202, the lower deflector 204, the upper trim deflector 206, and / or the lower trim deflector 208 may be spaced apart within the deflector stack of the electron optical column 110a to compensate for the deflection ratio. For example, the upper deflector 202 and the upper trim deflector 206 may be spaced apart to compensate for the deflection ratio.

[0052] According to another example, the spacing between one or more of the upper deflector 202, the lower deflector 204, the upper trim deflector 206, and / or the lower trim deflector 208 can be increased or decreased to compensate for the deflection ratio.

[0053] For example, one or more primary electron beams 106a can be directed into the upper deflector 202, the upper trim deflector 206, the lower trim deflector 208, and the lower deflector 204 of the deflector stack, in that order. Additionally, one or more secondary electron beams 118a can be directed into the deflector stack, such as into the lower deflector 204, the lower trim deflector 208, the upper trim deflector 206, and the upper deflector 202, in that order. It is noted that locating the upper deflector 202 and the lower deflector 204 at the top and bottom of the deflector stack can improve (e.g., increase and / or maximize) the deflection arm over a given length of the electron optical column 110a. This in turn can reduce and / or minimize the deflection (e.g. kick) of the primary electron beam 106a at the lower deflector 204 over a selected deflection length of the secondary electron beam(s) 118a. Reducing and / or minimizing the deflection (e.g. kick) of the primary electron beam(s) 106a traveling forward through the electron optical element(s) 112a at the lower deflector 204 can in turn reduce and / or minimize the deflection of the secondary electron beam(s) 118a traveling backward through the electron optical element(s) 112a. In this regard, the deflection of the secondary electron beam(s) 118a that results in a signal at the secondary electron detector(s) 200 can be increased and / or maximized.

[0054] In another embodiment, the thickness of one or more of the upper deflector 202, the lower deflector 204, the upper trim deflector 206, and / or the lower trim deflector 208 can be increased or decreased to compensate for the deflection ratio. For example, the upper deflector 202, the lower deflector 204, the upper trim deflector 206, and / or the lower trim deflector 208 can be of a selected thickness such that the upper deflector 202 and the lower deflector 204 are significantly thinner (e.g., thinner, flatter, or lower) than the upper trim deflector 206 and the lower trim deflector 208. The upper deflector 202 and the lower deflector 204 can be operated at a higher voltage even if they are thinner. In contrast, the upper trim deflector 206 and the lower trim deflector 208 would substantially fill the space of their deflector stack (and more generally the space of the electron optical column 110a) to take advantage of the lower voltages provided. It is noted, however, that the upper deflector 202 and the lower deflector 204 may be the same thickness as the upper trim deflector 206 and / or the lower trim deflector 208, or may be thicker. Thus, the above description should be taken as merely illustrative, and not as a limitation on the scope of the present disclosure.

[0055] It is noted that any of the presented examples can be combined to compensate for the deflection ratio. Therefore, the above description should not be taken as a limitation on the scope of the present disclosure, but merely as an illustration.

[0056] In an embodiment, the one or more electron optical elements 112a include one or more objective lenses 218. For example, but not limited to, the one or more objective lenses 218 may include a dynamic focus (DF) lens, such as a weak adjustable lens, that may be configured to keep the one or more primary electron beams 106a in focus as the specimen 114 is scanned laterally, thereby compensating for focal height variations. In another embodiment, the one or more objective lenses 218 may include a lower pole (LP) lens, such as a decelerating magnetic immersion lens, that may be configured to provide a selected level of electron optical performance during scanning and a long working distance relative to the specimen 114. In an embodiment, the one or more primary electron beams 106a are directed through the deflector stack into the one or more objective lenses 218.

[0057] Also, in embodiments, misalignment of the electron optical column 110a may be adjusted (or corrected) by the deflector stack. For example, a two-stage deflection process may be used to adjust (or correct) minor misalignment of the electron optical column 110a, which steers the beam within the one or more objective lenses 218 on the central axis to be parallel to the central axis. For example, a single-stage deflection process may be used to adjust major misalignment of the electron optical column 110a, which steers the beam within the one or more objective lenses 218 on the central axis to be at an angle.

[0058] In an embodiment, the primary electron beam(s) 106a are directed to the specimen 114 by a conical electron beam channel of an electron optical column 110a of the SEM-based characterization tool 100. For example, the primary electron beam(s) 106a may travel within the electron optical channel of the electron optical column 110a. The primary electron beam(s) 106a may be double deflected by the upper deflector 202 and the lower deflector 204. The primary electron beam(s) 106a may be dynamically astigmatized by the lower trim deflector 208. The primary electron beam(s) 106a may be statically astigmatized and / or deflected by the upper trim deflector 206 and the lower trim deflector 208. One or more objective lenses 218 can direct the primary electron beam(s) 106a onto the specimen 114 and generate one or more secondary electron beams 118a from backscattered and / or emitted electrons from the primary electron beam(s) 106a, thereby improving the spot size at the specimen 114 over the field of view.

[0059] In an embodiment, the secondary electron beam(s) 118a are directed to one or more secondary electron detectors 200 by a conical electron beam channel of the electron optical column 110a of the SEM-based characterization tool 100. For example, the secondary electron beam(s) 118a may be directed backwards in the electron optical channel of the electron optical column 110. As an example, the secondary electron beam(s) 118a may be deflected by the lower deflector 204 to travel parallel to the shape of the electron beam channel through the deflector stack (e.g., parallel to the cone surface), thereby improving the deflection field of view.

[0060] It is noted that the present disclosure is not limited to using multiple sets of electron optical deflectors in common and individual modes in the electron optical column of a SEM-based characterization tool. For example, multiple sets of optical deflectors may be used in common and individual modes in a characterization tool. Thus, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0061] Although this disclosure focuses generally on multi-column SEM characterization tools, the scope of this disclosure should not be construed as being limited to such configurations, rather, it is recognized that various embodiments of this disclosure can be extended to any type of electronic characterization tool, including, but not limited to, secondary electron (SE) characterization tools, multi-beam SEM characterization tools, etc.

[0062] Although this disclosure focuses generally on electronic characterization tools, the scope of this disclosure should not be construed as being limited to such configurations, rather, it is recognized that various embodiments of this disclosure can be extended to any type of characterization tool known in the art, including, but not limited to, focused ion beam (FIB) characterization tools and optical characterization tools.

[0063] FIG. 3 depicts a simplified schematic representation of an optical characterization tool 300 according to one or more embodiments of the present disclosure.

[0064] In accordance with embodiments, the optical characterization tool 300 may include any optical characterization tool known in the art, such as, but not limited to, an optical characterization tool that may operate at wavelengths corresponding to visible light, UV radiation, DUV radiation, VUV radiation, EUV radiation, and / or X-ray radiation.

[0065] In accordance with an embodiment, the optical characterization tool 300 further includes a radiation source array 302. In accordance with an embodiment, the radiation source array 302 further includes one or more radiation sources. For example, the radiation source array 302 can include, but is not limited to, a first radiation source 304a, a second radiation source 304b, a third radiation source 304c, and / or at least a fourth radiation source 304d.

[0066] In addition, the optical characterization tool 300 in accordance with an embodiment includes an optical column array 308. In addition, in an embodiment, the optical column array 308 includes one or more optical columns. For example, the optical column array 308 can include, but is not limited to, a first optical column 310a, a second optical column 310b, a third optical column 310c, and / or at least a fourth optical column 310d.

[0067] In some embodiments, one or more primary radiation beams are generated by one or more radiation sources. For example, primary radiation beams 306a, 306b, 306c, 306d may be generated by radiation sources 304a, 304b, 304c, 304d. In some embodiments, one or more primary radiation beams are directed to one or more optical columns in the optical column array 308. For example, one or more primary radiation beams 306a, 306b, 306c, 306d may be directed to optical columns 310a, 310b, 310c, 310d in the optical column array 308. In some embodiments, one or more source optical elements in the illumination beam source array 302 split and direct the radiation beams generated by one or more radiation sources to two or more optical columns in the optical column array 308.

[0068] In addition, in the embodiment, the one or more optical columns include one or more optical elements. For example, the optical columns 310a, 310b, 310c, 310d can include the optical elements 312a, 312b, 312c, 312d. In another embodiment, the one or more optical elements can include, but are not limited to, an optical deflector layer, an optical trim deflector layer, etc. As an example, one or more of the optical deflector layers or optical trim deflector layers can include one or more optical deflectors, including but not limited to, one or more prisms, one or more acousto-optic modulators, etc.

[0069] In addition, in an embodiment, one or more optical deflectors in the optical deflection layer are configured to perform one or more of two-stage deflection and / or dynamic astigmatism correction. In an embodiment, one or more optical trim deflectors are present in the optical trim deflector layer. In an embodiment, the optical trim deflectors in the optical trim deflector layer are configured to perform one or more of static deflection, static astigmatism correction, dynamic deflection, and / or dynamic astigmatism correction.

[0070] Also, in embodiments, the light deflector layer operates at a high voltage and the light trim deflector layer operates at a low voltage. However, it is noted that the light trim deflector layer may operate at a voltage equal to or higher than the light deflector layer. Thus, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0071] Also, in an embodiment, one or more light deflectors in a light deflector layer of an optical column (e.g., optical column 310a) are coupled to an amplifier or a common controller, and a select number of amplifiers are coupled to light deflectors in light deflector layers of additional optical columns (e.g., optical columns 310b, 310c, 310d) in the optical column array 308. It is noted that the use of a common amplifier for each individual light deflector is due to the static configuration and / or splitting of a portion of the dynamic deflection to the optical trim deflector layers. For example, the optical trim deflectors in the optical trim deflector layers can be individually driven and / or individually adjusted by a controller or amplifier in a particular optical column (e.g., optical column 310a, 310b, 310c, 310d) of the optical column array 308.

[0072] It is noted that the amplifiers and corresponding connectors coupled to the light deflectors in the light deflector layer may be larger (e.g., due to higher operating voltages) than the amplifiers and corresponding connectors coupled to the light trim deflectors in the light trim deflector layer. In addition, it is noted that smaller amplifiers may be more tightly routed, cabled and / or packaged and consume less power than larger amplifiers.

[0073] In this case, one or more amplifiers or common controllers coupled to the light deflectors in the light deflector layer can operate as a common driver for the light deflectors in the light deflector layer across one or more optical columns (e.g., optical columns 310a, 310b, 310c, 310d) in the optical column array 308. Additionally, when one or more primary radiation beams (e.g., primary radiation beams 306a, 306b, 306c, 306d) impinge on the specimen 314 to produce one or more secondary radiation beams, one or more amplifiers or controllers coupled to the optical trim deflectors in the optical trim deflector layer can act as smaller individual drivers for the optical trim deflectors in the optical trim deflector layer of one or more optical columns (e.g., optical columns 310a, 310b, 310c, 310d) in the optical column array 108 to fine-tune one or more secondary radiation beams (e.g., secondary radiation beams 318a, 318b, 318c, 318d). Thus, the overall volume, complexity, and power consumption of the optical characterization tool 300 can be reduced.

[0074] In an embodiment, the light deflector layers and the light trim deflector layers are arranged to define a light beam channel having a selected shape and centered on an axis passing through one or more optical elements (e.g., optical elements 312a, 312b, 312c, 312d) of one or more optical columns (e.g., optical columns 310a, 310b, 310c, 310d) of the optical column array 308. For example, the light beam channel may be conical in shape with a narrow end and a wide end, and the conical light beam channel may be defined by one or more design constraints of one or more optical elements (e.g., optical elements 312a, 312b, 312c, 312d) of one or more optical columns (e.g., optical columns 310a, 310b, 310c, 310d) of the optical column array 308. As an example, the conical light beam channel can be formed by a conical aperture in one or more optical elements (e.g., optical elements 312a, 312b, 312c, 312d) that can be defined by an inner surface of the optical element (e.g., optical elements 312a, 312b, 312c, 312d), particularly an inner surface that is tilted / graded with respect to an angle from a central axis passing through the optical element (e.g., optical elements 312a, 312b, 312c, 312d). It is noted that any description of the shape and operation of electron beam channels passing through one or more electron optical columns (e.g., electron optical columns 110a, 110b, 110c, 110d) of electron optical column array 108 may, for purposes of this disclosure, be extended to optical beam channels passing through one or more optical columns (e.g., optical columns 310a, 310b, 310c, 310d) of optical column array 308. Thus, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0075] In an embodiment, one or more optical columns in the optical column array 308 direct one or more primary radiation beams onto a specimen 314 held on a specimen stage 316. For example, the optical columns 310a, 310b, 310c, 310d may direct the primary radiation beams 306a, 306b, 306c, 306d onto the specimen 314 held on the specimen stage 316. In an embodiment, one or more radiation beams are generated at the specimen 314 in response to the one or more primary radiation beams impinging on the specimen 314. For example, one or more secondary radiation beams 318a, 318b, 318c, 318d may be generated at the specimen 314 in response to the primary radiation beams 306a, 306b, 306c, 306d impinging on the specimen 314.

[0076] In some embodiments, one or more of the optical columns may include one or more photodetectors. For example, one or more of the optical columns 310a, 310b, 310c, 310d may include one or more photodetectors. In some embodiments, one or more optical elements may direct one or more secondary radiation beams to one or more photodetectors of the optical columns. For example, optical elements 312a, 312b, 312c, 312d may direct secondary radiation beams 318a, 318b, 318c, 318d to one or more photodetectors in the optical columns 310a, 310b, 310c, 310d.

[0077] It is noted that all descriptions of specimen 114 may be extended to specimen 314. Additionally, it is noted that all descriptions of specimen stage 116 may be extended to specimen stage 316. Thus, the above descriptions should not be taken as limitations on the scope of the present disclosure, but merely as illustrative.

[0078] It is noted that all descriptions of radiation beam 306a may be extended to radiation beams 306b, 306c, and 306d for purposes of this disclosure. Additionally, it is noted that all descriptions of optical column 310a may be extended to optical columns 310b, 310c, and 310d for purposes of this disclosure. It is further noted that all descriptions of optical element(s) 312a may be extended to optical elements 312b, 312c, and 312d for purposes of this disclosure. It is further noted that all descriptions of secondary radiation beam 318a may be extended to secondary radiation beams 318b, 318c, and 318d for purposes of this disclosure. Accordingly, the above descriptions should be taken as merely illustrative and not as limitations on the scope of the present disclosure.

[0079] FIG. 4 illustrates a characterization system 400 according to one or more embodiments of the present disclosure.

[0080] The characterization system 400 according to an embodiment includes a characterization tool 402. The characterization system 400 may incorporate any suitable characterization tool 402 known in the art. In general, the characterization tool 402 may include any suitable characterization tool for characterizing one or more photomasks / reticles or wafers.

[0081] In one embodiment, characterization tool 402 includes one or more characterization tools and / or characterization components configured to characterize one or more photomasks / reticles or wafers as known in the art. For example, characterization tool 402 may include, but is not limited to, SEM-based characterization tool 100, optical characterization tool 300, FIB-based characterization tools, etc. In general, characterization tool 402 may include, but is not limited to, inspection tools, review tools, imaging-based overlay metrology tools, etc.

[0082] Additionally, in embodiments, characterization system 400 includes a controller 404. Moreover, in embodiments, controller 404 is operatively coupled to one or more components of characterization tool 402 such that controller 404 can direct any of the components of characterization tool 402 to perform any one or more of the functions described elsewhere in this disclosure.

[0083] In an embodiment, controller 404 also includes one or more processors 406 and a memory 408. In an embodiment, memory 408 further includes a set of program instructions 410 stored therein. In an embodiment, set of program instructions 410 is configured to cause one or more processors 406 to perform any one or more process steps described elsewhere in this disclosure.

[0084] The controller 404 may be configured to receive and / or acquire data or information from tools or other systems within the characterization tool 402 via a transmission medium, such as a wired and / or wireless link. Additionally, the controller 404 may be configured to transmit data or information (e.g., output of one or more procedures of the inventive concepts described herein) to one or more systems or tools within the characterization tool 402 via a transmission medium, such as a wired and / or wireless link, which may act as a data link between the controller 404 and other subsystems of the characterization tool 402. Additionally, the controller 404 may be configured to send data to external systems via a transmission medium, such as a network connection.

[0085] The one or more processors 406 may include any one or more processing elements known in the art. In this sense, the one or more processors 406 may include any microprocessor device configured to execute algorithms and / or program instructions. For example, the one or more processors 406 may be comprised of a desktop computer, a mainframe computer system, a workstation, an image computer, a parallel processor, a handheld computer (e.g., a tablet, smartphone, or phablet), or other computer system (e.g., a networked computer). In general, the term "processor" may be broadly defined to include any device having one or more processing elements that execute a set of program instructions 410 obtained from a non-transitory storage medium (e.g., memory 408). Additionally, the various subsystems of the characterization tool 402 may incorporate processors or logic elements suitable for performing at least a portion of the steps described elsewhere in this disclosure. Therefore, the above description should be taken as merely illustrative and not as a limitation on the scope of the present disclosure.

[0086] The memory 408 may include any storage medium known in the art suitable for storing a set of program instructions 410 executable by the associated processor(s) 406. For example, the memory 408 may include a non-transitory storage medium. By way of example, but not limited to, the memory 408 may include a read-only memory (ROM), a random access memory (RAM), a magnetic or optical storage device (e.g., disk), a magnetic tape, a solid-state drive, and the like. The memory 408 may be configured to provide display information to a display device associated with a user interface. Additionally, the memory 408 may be configured to store user input information from a user input device associated with a user interface. The memory 408 may be housed in a common housing of the controller 404 with the processor(s) 406. Alternatively or additionally, the memory 408 may be located remotely relative to the spatial location of the processor(s) 406 and / or the controller 404. As an example, one or more of the processors 406 and / or controllers 404 may access a remote memory 408 (eg, a server) accessible over a network (eg, the Internet, an intranet, etc.).

[0087] Also, in embodiments, data from one or more components of characterization tool 402 is read and / or processed by one or more sets of electronic circuitry coupled to controller 404 and / or software stored on controller 404. Furthermore, in embodiments, images generated by or on one or more components of characterization tool 402 are read and / or processed by one or more sets of electronic circuitry coupled to controller 404 and / or software stored on controller 404.

[0088] Additionally, the characterization system 400 according to an embodiment includes a user interface. Additionally, in an embodiment, the user interface is coupled (e.g., physically and / or communicatively coupled) to the controller 404. Additionally, in an embodiment, the user interface includes a display device. Additionally, in an embodiment, the user interface includes a user input device. Additionally, in an embodiment, the display device is coupled to the user input device. For example, the display device may be coupled to the user input device via a transmission medium, including, for example, a wired and / or wireless section.

[0089] Although embodiments of the present disclosure depict that the controller 404 may be coupled to or integrated within the characterization tool 402, the controller 404 is not an integral or required component of the characterization tool 402. Additionally, although embodiments of the present disclosure depict that the user interface may be coupled to or integrated within the controller 404, the user interface is not an integral or required component of the controller 404 or the characterization tool 402. Thus, the above description should be taken as merely illustrative, and not as a limitation on the scope of the present disclosure.

[0090] As one of ordinary skill in the art will recognize, the current state of the art has advanced to the point where there is little difference between hardware, software, and / or firmware implementations of systems of the embodiments, and the use of hardware, software, and / or firmware is generally (but not always, as the choice between hardware and software can be critical in certain circumstances) a design choice that represents a cost vs. efficiency trade-off. As one of ordinary skill in the art will recognize, there are various means (e.g., hardware, software, and / or firmware) that may implement or realize the processes and / or systems and / or other technologies described herein, and which means will be appropriate will depend on the context in which the processes and / or systems and / or other technologies are used. For example, if an implementer determines that speed and accuracy are essential, the implementer may choose a primarily hardware and / or firmware implementation, if flexibility is instead essential, the implementer may choose a primarily software implementation, and if neither of these is the case, the implementer may choose some combination of hardware, software, and / or firmware. Thus, there are several potential means by which the processes and / or apparatus and / or other technologies described herein may be implemented, none of which is inherently superior to the others, and which means to utilize is a matter of choice governed by variables such as the circumstances in which it is valued and the particular concerns of the practitioner (e.g., speed, flexibility, or predictability).As one of ordinary skill in the art will recognize, the optical aspects of the embodiments will typically employ optically oriented hardware, software, and / or firmware.

[0091] In some implementations described herein, software and other control structures may be incorporated into logic implementations and the like. For example, one or more current paths in electronic circuits may be appropriately configured and arranged to implement various functions described herein. In some implementations, one or more media may be configured to carry device-detectable implementations when operable device-detectable instructions that can be executed as described herein are carried or transmitted by the media. In some variations, for example, implementations may incorporate updates or modifications to existing software or firmware, or gate arrays or programmable hardware, such as by receiving or transmitting one or more instructions associated with one or more operations described herein. Alternatively or additionally, in some variations, implementations may incorporate dedicated hardware, software, firmware components, and / or general-purpose components that execute or otherwise invoke the dedicated components. Specifications and other implementations may be transmitted over one or more tangible transmission media as described herein, or may, but need not, be transmitted via packet transmission, or may be transmitted by delivery in a distributed medium at various times.

[0092] Alternatively or additionally, implementations may incorporate the execution of specialized instruction sequences or invocation of circuits to effectuate, invoke, coordinate, request, or otherwise cause substantially any functional operation described herein to occur one or more times. In some variations, operations and other logical descriptions herein may be expressed as source code and then compiled or otherwise invoked as executable instruction sequences. In some contexts, for example, implementations may be provided in whole or in part as source code, e.g., C++ or other code sequences. In some implementations, the source code or other code implementations may be compiled / embodied / translated / converted into a higher level description language using technology commercially available in the art (e.g., by first embodiing the described technology in the C, C++, python™, Ruby on Rails™, Java™, PHP, .NET™, or Node.js™ programming languages, and then converting the programming language implementations into a logic synthesizable language implementation, a hardware description language implementation, a hardware design simulation implementation, and / or other similar representation mode(s). For example, some or all of the logic representations (e.g., computer programming language implementations) may be specified in a Verilog™-style hardware description (e.g., in a Hardware Description Language (HDL) and / or Very High Speed ​​Integrated Circuit Hardware Description Language (VHDL)) or other circuit model and then used to generate a tangible implementation with hardware (e.g., an application specific integrated circuit). In light of these teachings, those skilled in the art will recognize how to obtain, configure and optimize suitable transmission or information processing elements, material sources, actuators and other structures.

[0093] In the above detailed description, the apparatus, devices and / or processes of various embodiments are described through the use of block diagrams, flow charts and / or examples. To the extent that the block diagrams, flow charts and / or examples include one or more functions and / or operations, those skilled in the art will appreciate that the functions and / or operations in the block diagrams, flow charts or examples, individually and / or collectively, may be implemented or performed by a wide variety of hardware, software, firmware, or substantially any combination thereof. According to some embodiments, portions of the subject matter described herein may be implemented in an application specific integrated circuit (ASIC), field programmable gate array (FPGA), digital signal processor (DSP), or other integrated form. However, those of ordinary skill in the art will recognize that certain aspects of the disclosed embodiments may be equivalently implemented, in whole or in part, in integrated circuits, as one or more computer programs running on one or more computers (e.g., one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., one or more programs running on one or more microprocessors), as firmware, or nearly any combination thereof, and that designing such circuitry and / or writing such software and / or firmware code would be within the skill of one of ordinary skill in the art in light of this disclosure. In addition, those of ordinary skill in the art will recognize that mechanisms of the disclosed subject matter may be distributed as a program product in a variety of forms, and that illustrative embodiments of the disclosed subject matter apply regardless of the specific type of signal-bearing medium used to actually effect such distribution.Examples of signal bearing media include, but are not limited to, recordable media, such as floppy disks, hard disk drives, compact disks (CDs), digital video disks (DVDs), digital tape, computer memory, and transmission media, such as digital and / or analog communications media (e.g., fiber optic cables, wave guides, wired communications links, wireless communications links (e.g., transmitters, receivers, transmitting logic, receiving logic, etc.)).

[0094] In general, as will be appreciated by those skilled in the art, the various embodiments described herein can be implemented, individually and / or collectively, by various types of electromechanical systems having a wide variety of electrical components, such as hardware, software, firmware, and / or nearly any combination thereof, and a wide variety of mechanical force or motion imparting components, such as rigid bodies, springs or torsion bodies, hydraulic drives, electromagnetic drives, and / or nearly any combination thereof. Accordingly, the term "electromechanical system" as used herein includes, but is not limited to, an electrical circuit operably coupled to a transducer (e.g., an actuator, motor, piezoelectric crystal, microelectromechanical system (MEMS), etc.), an electrical circuit having at least one discrete electrical circuit, an electrical circuit having at least one integrated circuit, an electrical circuit having at least one application specific integrated circuit, an electrical circuit forming a general purpose information processing device configured by a computer program (e.g., a general purpose computer configured by a computer program that at least partially implements the processes and / or devices described herein, or a microprocessor configured by a computer program that at least partially implements the processes and / or devices described herein), an electrical circuit forming a storage device (e.g., various forms of memory (e.g., random access, flash, read only, etc.)), an electrical circuit forming a communications device (e.g., a modem, a communications switch, a photoelectric device, etc.), and / or non-electrical, e.g., optical or other analogs thereof. As will be appreciated by those skilled in the art, examples of electromechanical systems include, but are not limited to, various consumer electronic systems, medical devices, and other systems, such as powered transportation systems, factory automation systems, security systems, and / or communication / information processing systems. As will be appreciated by those skilled in the art, electromechanical, as used herein, is not necessarily limited to systems with both electrical and mechanical drives, unless the context indicates otherwise.

[0095] In general, as will be appreciated by those skilled in the art, the various aspects described herein may be implemented, individually and / or collectively, in a wide variety of hardware, software, firmware, and / or any combination thereof, and may be viewed as comprising various types of "electrical circuitry." Thus, as used herein, "electrical circuitry" includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose information processing device (e.g., a general purpose computer configured with a computer program that at least partially executes and / or implements the processes and / or devices described herein, or a microprocessor configured with a computer program that at least partially executes and / or implements the processes and / or devices described herein), electrical circuitry forming a storage device (e.g., various forms of memory (e.g., random access, flash, read only, etc.)), and / or electrical circuitry forming a communications device (e.g., a modem, a communications switch, a photoelectric device, etc.). As those skilled in the art will recognize, the subject matter described herein may be implemented in analog form, digital form, or any combination thereof.

[0096] As will be appreciated by those skilled in the art, at least a portion of the devices and / or processes described herein may be integrated into a data processing system. As will be appreciated by those skilled in the art, a data processing system typically includes one or more of the following: a system unit housing, a video display device, a memory, such as volatile or non-volatile memory, a processor, such as a microprocessor or digital signal processor, information processing entities, such as an operating system, drivers, graphical user interfaces and application programs, one or more interactive devices (e.g., touch pads, touch screens, antennas, etc.), and / or a control system having feedback loops and control motors (e.g., feedback for sensing position and / or velocity, control motors for moving and / or adjusting members and / or quantities). The data processing system may be implemented using suitable commercially available components, such as those commonly found in data information processing / communication and / or network information processing / communication systems.

[0097] As those skilled in the art will recognize, the components (e.g., operations), devices, objects, and accompanying discussion described herein are used as examples for conceptual clarity, and various configuration modifications are contemplated. Thus, as used herein, the specific exemplars described above and the accompanying discussion are intended to be representative of their more general class. In general, the use of any specific exemplar is intended to be representative of that class, and the absence of specific components (e.g., operations), devices, and objects should not be construed as a limitation.

[0098] Although user is described in the singular herein, those skilled in the art will appreciate that, unless the context dictates otherwise, user can represent or represent a human user, a robot user (e.g., a data processing entity), and / or substantially any combination thereof (e.g., a user may be assisted by one or more robotic agents). As those skilled in the art will appreciate, generally, the same can be said about "sender" and / or other entity-oriented terms used herein, unless the context dictates otherwise.

[0099] With respect to the use of virtually all plural and / or singular terms herein, those of ordinary skill in the art may interpret the plural to singular and / or singular to plural, as appropriate to the context and / or application. For the sake of clarity, the present application has not explicitly set forth the various singular / plural permutations.

[0100] The subject matter described herein is depicted in places with various components embedded or connected to various other components. As will be appreciated, the illustrated architectures are merely exemplary, and in fact many other architectures may be implemented to achieve the same functionality. Conceptually, any arrangement of components that achieves the same functionality is substantially "associated" with one another to achieve the desired functionality. Thus, any two components in this application that are combined to achieve a particular functionality may be considered to be "associated" with one another to achieve the desired functionality, regardless of the architecture or intervening components. Similarly, any two components so associated may also be viewed as "operably connected" or "operably coupled" to one another to achieve the desired functionality, and any two components that can be so associated may also be viewed as "operably connectable" to one another to achieve the desired functionality. Examples of operably coupleable include, but are not limited to, physically coupleable and / or physically interacting components, and / or wirelessly interactable and / or wirelessly interacting components, and / or logically interacting and / or logically interacting components, etc.

[0101] In some cases, one or more components may be referred to herein as being "configured to," "configurable to," "operable to," "adapted to," "may," "adaptable to," etc. As one of ordinary skill in the art will recognize, unless the context requires otherwise, these terms (e.g., "configured to") can generally encompass active and / or inactive and / or standby components.

[0102] Although specific aspects of the subject matter described herein have been shown and described, it will be appreciated by one of ordinary skill in the art that changes and modifications may be made based on the teachings herein without departing from the subject matter described herein and its broader aspects, and all such changes and modifications are to be included within the scope of the appended claims as being within the true spirit and scope of the subject matter described herein. As will be appreciated by one of ordinary skill in the art, generally, the terms used in this application, particularly in the appended claims (e.g., the body of the appended claims) are generally intended to be "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "including" should be interpreted as "including but not limited to," etc.). As will also be appreciated by one of ordinary skill in the art, if a specific number of inclusion features are intended, then such intent will be clearly stated in the claim, and the absence of such features indicates no intent. For example, as an aid to understanding, some of the claims below include the introduction of claim features through the use of the introductory phrases "at least one" and "one or more." However, the use of such phrases should not be construed as implying that the introduction of a claim feature with the indefinite article "a" or "an" limits all individual claims containing that claim feature to containing only one of that feature, even when the introductory phrase "one or more" or "at least one" coexists with an indefinite article, such as "a" or "an" in the very claim (e.g., "a" and / or "an" should be understood to generally mean "at least one" or "one or more"), and the same is true with respect to the introduction of claim features through the use of a definite article. In addition, even if a specific number of elements are explicitly stated in a claim, as would be recognized by a person skilled in the art, the number should usually be interpreted as meaning at least the specified number (e.g., the bare expression "two elements" without other modifiers usually means at least two elements or more than two elements).Furthermore, where a convention similar to "at least one of A, B, and C, etc." is used, such syntax is generally intended to be consistent with how a person of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include, but is not limited to, systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or systems having A, B, and C, etc.). Where a convention similar to "at least one of A, B, or C, etc." is used, such syntax is generally intended to be consistent with how a person of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include, but is not limited to, systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or systems having A, B, and C, etc.). As will also be appreciated by those of ordinary skill in the art, disjunctive conjunctions and / or phrases that normally present two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the inclusion of either, either, or both terms, unless the context dictates otherwise. For example, the phrase "A or B" would normally be understood to encompass the possibilities of "A" or "B" or "A and B."

[0103] In the context of the appended claims, those skilled in the art will appreciate that the operations recited therein may generally be performed in any order. Additionally, while various operational flows are presented in sequence(s), it should be understood that the various operations may be performed in an order different from that depicted, or may be performed simultaneously. Examples of such alternative orders may include overlapping, interpolating, interleaving, reordering, progressive, preparatory, additional, simultaneous, reversed, and other variable orders, unless the context dictates otherwise. Additionally, the use of terms such as "according to," "related to," and other past tense adjectives are generally not intended to exclude such variations, unless the context dictates otherwise.

[0104] While specific embodiments of the present invention have been illustrated, it will be apparent that those skilled in the art may effect various modifications and embodiments of the present invention without departing from the scope and spirit of the disclosure set forth above. The present disclosure and many of its attendant advantages will be understood from the above description, and it will also be apparent that various changes in the form, configuration and arrangement of the components may be made without departing from the disclosed subject matter or losing all of its essential advantages. The described embodiments are merely illustrative, and it is the intent of the following claims to encompass and embrace all such modifications. The scope of the present invention is therefore to be limited only by the scope of the appended claims.

Claims

1. 1. A scanning electron microscopy (SEM) system comprising: a plurality of electron beam sources, at least some of the electron beam sources configured to generate a primary electron beam; and an electron optical column array including a plurality of electron optical columns, an electron optical column of the plurality of electron optical columns comprising: a plurality of electron optical elements arranged to form a cone-shaped electron beam channel configured to direct the primary electron beam at a specimen fixedly supported on a stage, the specimen emitting an electron beam in response to the primary electron beam; and the conical electron beam channel having at least one electron detector and configured to direct the electron beam to the at least one electron detector; and deflecting the electron beam by at least one electron optical element of the plurality of electron optical elements to travel parallel to a conical surface of the conical electron beam channel and direct the electron beam toward the at least one electron detector; system.

2. 2. The system of claim 1, wherein the conical electron beam channel is formed by the action of a conical aperture in at least one of the plurality of electron optical elements.

3. 2. The system of claim 1 , wherein the conical electron beam channel is formed by an inner surface of a first electron optical element and an inner surface of at least one additional electron optical element of the plurality of electron optical elements, the inner surface of the first electron optical element and the inner surface of the at least one additional electron optical element being each located a selected distance from a central axis passing through the plurality of electron optical elements, and at least one of the inner surface of the first electron optical element and the inner surface of the at least one additional electron optical element including an inner surface that is sloped based on an angle relative to a central axis passing through the plurality of electron optical elements.

4. 4. The system of claim 3, wherein said selected distance from said central axis to said inner surface of a first electron-optical element is different from said selected distance from its central axis to said inner surface of said at least one additional electron-optical element.

5. 2. The system of claim 1, wherein the conical electron beam channel is defined by a conical aperture in at least one electron optical element of the plurality of electron optical elements together with an inner surface of a first electron optical element of the plurality of electron optical elements and an inner surface of at least one additional electron optical element of the plurality of electron optical elements; The system wherein the inner surfaces of the first electron optical element and the at least one additional electron optical element are each located a selected distance from a central axis passing through the plurality of electron optical elements.

6. 2. The system of claim 1, wherein the conical electron beam channel narrows as the primary electron beam approaches the specimen.

7. 7. The system of claim 6, wherein a narrow aperture of said conical electron beam channel is matched to a size of said electron beam.

8. 2. The system of claim 1, wherein said conical electron beam channel widens as said electron beam approaches said at least one electron detector.

9. 9. The system of claim 8, wherein a wide aperture of said cone-shaped electron beam channel is sized to fit said at least one electron detector.

10. 2. The system of claim 1, wherein the plurality of electron-optical elements comprises one or more objective lenses.

11. 1. An electro-optical system comprising: an electron optical column array having a plurality of electron optical columns, an electron optical column of the plurality of electron optical columns having a plurality of electron optical elements arranged to form a cone-shaped electron beam channel, the cone-shaped electron beam channel configured to direct a primary electron beam at a specimen secured on a stage, the specimen emitting an electron beam in response to the primary electron beam; and A system comprising at least one electron detector, the conical electron beam channel configured to direct the electron beam to the at least one electron detector, and the system deflects the electron beam by at least one electron optical element of the plurality of electron optical elements to travel parallel to a conical surface of the conical electron beam channel and direct the electron beam to the at least one electron detector.

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