Reducing Thermal Magnetic Field Noise in TEM Corrector Systems

Abstract

A system for reducing the generation of thermal magnetic field noise in an optical element of a microscope system is disclosed. An example microscope optical element with reduced Johnson noise generation according to the present disclosure includes an inner core composed of an electrically insulating material and an outer coating composed of an electrically conductive material. The product of the thickness of the outer coating and the electrical conductivity is less than 0.01 Ω ‑1 The outer coating causes a reduction in Johnson noise generated by the optical element by more than 2×, 3×, or an order of magnitude or greater. In certain example embodiments, the optical element is a corrector system with reduced Johnson noise generation. Such a corrector system includes an outer magnetic multipole and an inner electrostatic multipole. The inner electrostatic multipole includes an inner core composed of an electrically insulating material and an outer coating composed of an electrically conductive material.

Description

Background Art

[0001] Recently, thermal magnetic field noise (Johnson noise) from magnetic and nonmagnetic conductive components close to the electron beam has been identified as a cause of decoherence in electron microscope systems. Thermal magnetic field noise originates from thermally driven currents in conductive magnetic materials close to the imaging beam as well as in nonmagnetic materials such as yokes, lenses, and multipoles. This is particularly true in chromatic aberration correctors (C C ) (a corrector system designed to correct the axial chromatic aberration coefficient) and C C / C S Corrector (which corrects C C This is particularly a problem in the spherical aberration coefficients (and spherical aberration coefficients), which eliminates the main resolution limiting factor, making thermal magnetic field noise the limiting aberration in high-resolution TEM systems. For example, in the quadrupole-octupole C C / C S In the corrector, the main contribution to the thermal magnetic field noise comes from two C C correction element (i.e., a four-pole Wien filter). Therefore, although the current TEM C C / C S Correctors are able to compensate for spherical and chromatic aberrations, but they also generate thermal magnetic field noise, which is at least partly responsible for the larger than ~ This problem is exacerbated by the fact that the blur caused by thermal magnetic field noise increases with the square root of the lens gap.

[0002] Since thermal magnetic noise is proportional to the square root of temperature, cooling solutions have been proposed to compensate for this thermal magnetic noise. For example, cooling systems have been designed to address thermal magnetic noise using various techniques / elements (e.g., liquid nitrogen, heat pipes, and / or cooling rods). However, C C / C S Cooling of the corrector is both challenging to design and expensive to implement, making it not a practical solution outside of cryogenic systems. Therefore, a cheaper and easier to implement solution is needed to correct thermal magnetic field noise in imaging systems. Summary of the invention

[0003] A system for reducing the generation of thermal magnetic field noise in an optical element of a microscope system is disclosed. An example microscope optical element with reduced Johnson noise generation according to the present disclosure includes an inner core composed of an electrically insulating material and an outer coating composed of an electrically conductive material. The product of the thickness (t) and the electrical conductivity (σ) of the outer coating is less than 0.01 Ω -1 , 0.001Ω -1 , 0.0001 Ω -1The outer coating according to the present invention results in a reduction of the Johnson noise generated by the optical element by 2×, 3×, an order of magnitude or more. In a specific example embodiment, the optical element is a corrector system with reduced Johnson noise generation. Such a corrector system includes a C composed of an outer magnetic multipole and an inner electrostatic multipole. C Correction Element. The internal electrostatic multipole comprises an inner core composed of an electrically insulating material and an outer coating composed of an electrically conductive material. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The detailed description is described with reference to the accompanying drawings. In the drawings, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. The same reference numbers in different drawings indicate similar or identical items.

[0005] Figure 1 An optical assembly configured to reduce thermomagnetic noise in a microscope imaging system according to the present invention is schematically illustrated.

[0006] Figure 2 Depicts an environment of a microscope imaging system including one or more optical components configured to reduce thermal magnetic noise during processing, imaging, and / or evaluation of a sample.

[0007] Figure 3 and Figure 4 A schematic example corrector system configured in accordance with the present invention to produce reduced thermal magnetic noise during use in a charged particle microscopy system is shown.

[0008] Figure 5 Example graphs are shown illustrating the contribution of thermomagnetic noise (Johnson noise) to the optical transfer function of various system configurations in accordance with the present invention.

[0009] Throughout the several views of the drawings, like reference numerals refer to corresponding parts. Generally, in the drawings, elements that may be included in a given example are shown in solid lines, while elements that are optional for a given example are shown in dashed lines. However, elements shown in solid lines are not necessary for all examples of the present disclosure, and elements shown in solid lines may be omitted from a particular example without departing from the scope of the present disclosure. DETAILED DESCRIPTION

[0010] Methods and systems for reducing thermal magnetic noise in a microscope imaging system are disclosed. Specifically, the methods and systems relate to an optical component comprising an inner core composed of an electrically insulating material and an outer coating composed of an electrically conductive material surrounding the inner core. In some embodiments of the present invention, the optical component is a corrector (e.g., C C / C SIn some example embodiments, the presence of this layer of conductive material surrounding the inner electrically insulating core reduces the thermal magnetic field noise generated by the corrector by 2×, 3×, an order of magnitude, or more.

[0011] Figure 1 1 is a schematic illustration of an optical assembly 100 configured to reduce thermal magnetic noise in a microscope imaging system according to the present invention. Specifically, Figure 1 A cross section of the optical assembly 102 is shown proximate to the charged particle beam path 104 . Figure 1 The charged particle beam path 104 is illustrated as following z The cross section of the optical component 102 is illustrated as xy The optical component 102 includes an inner core 106 composed of an electrically insulating material. In various embodiments, the inner core 106 may be composed of various resistive materials, such as ceramic materials, glassy materials, quartz, semiconductor materials, etc. Those skilled in the art will understand that this list of potential resistive materials is not exhaustive, and various electrically insulating materials (and / or combinations thereof) may be selected depending on the function of the optical element or system in which they reside.

[0012] Figure 1 The optical element 102 is further shown as including an outer coating 108 composed of a conductive material that completely surrounds the inner core. However, in other embodiments, the outer coating may not completely surround the inner core. The conductive material is selected so that the thickness of the outer coating ( t ) multiplied by the conductivity of the conductive material (σ) is less than 0.01 Ω -1 , 0.001 Ω -1 , and / or 0.0001 Ω -1 In various embodiments, the outer coating 108 can be electrically grounded and / or a voltage can be applied to the outer coating 108. Additionally, in various embodiments, the outer coating 108 can have a sheet resistance greater than 10 kΩ and / or greater than 100 kΩ (i.e., ). Furthermore, the presence of coating 108 on optical element 102 results in the amount of thermal magnetic field noise (ie, Johnson noise) generated by optical element 102 being reduced by at least 2×, 3×, or an order of magnitude compared to known optical elements.

[0013] In various embodiments of the present invention, the optical element 102 may correspond to various optical microscope elements or components thereof. For example, the optical element 102 may correspond to an electrode, a multipole element, a deflector, or a component of a corrector, such as a Cc and / or Cs corrector.

[0014] Figure 1The optical assembly 100 is also illustrated as including an optional second optical element 110, which includes an inner core 106 composed of an electrically insulating material surrounded by an outer coating 112 composed of an electrically conductive material. An example embodiment having two such optical elements may be a beam deflector system. According to the present invention, this beam deflector system will be able to cause deflection of the charged particle beam 104 while generating a greatly reduced amount of thermal magnetic noise when the charged particle beam 104 passes close to the optical elements 102 and 110.

[0015] Figure 2 An illustration of an environment 200 for a microscope imaging system including one or more optical components configured to reduce thermal magnetic noise during processing, imaging, and / or evaluation of a sample. Specifically, Figure 2 An example environment 200 is shown that includes an example microscope system 202 for studying a sample 204 that includes both a deflector system 206 and a corrector system 208 that are each configured in accordance with the present invention to reduce the amount of thermal magnetic field noise that they generate. Specifically, Figure 2 The example microscope system 202 is shown as including C S / C C Corrector system 208 .

[0016] The example microscope system 202 may be or include one or more different types of optical and / or charged particle microscopes, such as, but not limited to, a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), a transmission electron microscope (TEM), a charged particle microscope (CPM), a cryo-compatible microscope, a focused ion beam microscope (FIB), a dual beam microscope system, or a combination thereof. Figure 2 The example microscope system 202 is shown as a TEM microscope system.

[0017] Figure 2 The example microscope system 202 is depicted as including an electron source 210 (e.g., a thermal electron source, a Schottky emission source, a field emission source, etc.) that emits an electron beam 212 along an electron emission axis 214 and toward a sample 204. The electron emission axis 214 is a central axis extending from the electron source 210 along the length of the example microscope system 202 and through the sample 204. Figure 2 The example microscope system 202 is depicted as including an electron source 210 , but in other embodiments, the example microscope system 202 may include a charged particle source, such as an ion source, configured to emit a plurality of charged particles toward the sample 204 .

[0018] The accelerator lens 216 accelerates / decelerates, focuses and / or directs the electron beam 216 to the electron focusing column 218. The electron condenser column 218 focuses the electron beam 212 so that it is incident on at least a portion of the sample 204. In addition, the condenser column 218 can correct and / or adjust the aberrations (e.g., geometric aberrations, chromatic aberrations) of the electron beam 212. In some embodiments, the electron focusing column 218 may include one or more of an aperture, a transfer lens, a scanning coil, a condenser lens, a deflector 206, an objective lens, etc., which together focus the electrons from the electron source 210 to a small spot on the sample 204 (STEM mode) or provide a wider illumination beam on the sample (TEM mode).

[0019] Figure 2 Further depicted is an inset cross-sectional view 220 of a deflector 206 in accordance with the present invention, which is configured to provide an electric field to deflect a beam. The cross-sectional view 220 shows the deflector 206 as including an inner core 222 comprised of an electrically insulating material. In various embodiments, the inner core 222 may be comprised of various resistive materials, such as, for example, ceramic materials, vitreous materials, quartz, semiconductor materials, and the like. Those skilled in the art will appreciate that this list of potential resistive materials is not exhaustive, and that various electrically insulating materials (and / or combinations thereof) may be selected depending on the function of the optical element or system in which it resides. The deflector 206 is further shown as including an outer coating 224 comprised of a conductive material that completely surrounds the inner core. The conductive material is selected such that the thickness of the outer coating ( t ) multiplied by the conductivity of the conductive material (σ) is less than 0.01 Ω -1 , 0.001 Ω -1 , and / or 0.0001 Ω -1 In various embodiments, the outer coating 224 can be electrically grounded, and / or can have a sheet resistance greater than 10 kΩ and / or greater than 100 kΩ. The presence of the outer coating 224 on the deflector 206 can result in an amount of thermomagnetic noise (i.e., Johnson noise) generated by the deflector 206 being reduced by at least 2×, 3×, or an order of magnitude compared to known optical elements.

[0020] Different locations of the sample 204 can be scanned by adjusting the electron beam direction via the deflector 206 and / or the scanning coils. In this way, the electron beam 212 acts as an imaging beam that scans across the surface layers of the sample (i.e., the surface of the layer close to the microscope column 202 and / or irradiated by the electron beam 212). This irradiation of the surface layers of the sample 204 causes the constituent electrons of the electron beam 212 to interact with the constituent elements / molecules / features of the sample, causing the constituent elements / molecules / features to cause emissions to be emitted by the sample 204. The specific emissions released are based on the corresponding elements / molecules / features that caused them to emit, so that the emissions can be analyzed to determine information about the corresponding elements / molecules.

[0021] Figure 2 Further illustrating a detector system 226 for detecting emission generated from the electron beam 212 incident on the sample 204. The detector system 226 may include one or more detectors positioned or otherwise configured to detect such emission. In various embodiments, different detectors and / or different portions of a single detector may be configured to detect different types of emission, or configured such that parameters of the emission detected by different detectors and / or different portions are different.

[0022] Figure 2 Further included is an inset cross-sectional view 230 of a corrector system 208 according to the present invention. The corrector system 208 includes a plurality of external magnetic elements 232 (e.g., magnetic multipoles including 8 or 12 poles) and a plurality of electrodes 234 (e.g., electrostatic multipoles), wherein the electrodes 234 are positioned closer to the charged particle beam 212 than the external magnetic elements 232.

[0023] The cross-sectional view 230 shows the electrode 234 as including an inner core composed of an electrically insulating material (e.g., a ceramic material, a vitreous material, quartz, a semiconductor material, etc.) and an outer coating composed of a conductive material that completely surrounds the inner core. The conductive material is selected so that the thickness of the outer coating ( t ) multiplied by the conductivity of the conductive material (σ) is less than 0.01 Ω -1 , 0.001 Ω -1 , and / or 0.0001 Ω -1 In various embodiments, the outer coating may be electrically grounded, and / or may have a sheet resistance greater than 10 kΩ and / or greater than 100 kΩ. The presence of the outer coating 224 on the electrode 234 results in an amount of thermomagnetic noise (i.e., Johnson noise) generated by the corrector system 208 being reduced by at least 2×, 3×, or an order of magnitude compared to known optical elements. Figure 2 The corrector system 208 is further shown as optionally including a magnetic element 232 and a barrier between the electrode 234. For example, the barrier 236 may partially define a vacuum region through which the charged particle beam 212 travels.

[0024] Figure 2 The example microscope system 202 is further shown as further including a sample holder 228. The sample holder 228 is configured to hold the sample 204, and can translate, rotate, and / or tilt the sample 204 relative to the example microscope system 202.

[0025] The environment 200 is also shown to include one or more computing devices 238 connected to the detector system 226. The detector system 226 is further configured to generate data / data signals corresponding to the detected emissions and transmit the data / data signals to the one or more computing devices 238. Those skilled in the art will appreciate that Figure 2The computing device 238 depicted in the Figure is illustrative only and is not intended to limit the scope of the present disclosure. The computing systems and devices may include any combination of hardware or software that can perform the indicated functions, including computers, network devices, Internet appliances, PDAs, wireless phones, controllers, oscilloscopes, amplifiers, etc. The computing device 238 may also be connected to other devices not illustrated, or alternatively may operate as a stand-alone system.

[0026] It should also be noted that one or more of the computing devices 238 may be a component of the example microscope system 202, may be a stand-alone device separate from the example microscope system 202 that communicates with the example microscope system 202 via a network communication interface, or a combination thereof. For example, the example microscope system 202 may include a first computing device 238 that is an integral part of the example microscope system 202 and that acts as a controller that drives the operation of the example charged-particle microscope system 202 (e.g., by operating a scanning coil to adjust a scanning position on a sample, etc.). In such embodiments, the example microscope system 202 may also include a second computing device 238 that is a desktop computer separate from the example microscope system 202 and that is executable to process data received from the detector system 226 to generate an image of the sample 204 and / or perform other types of analysis or post-processing on the detector data. The computing device 238 may be further configured to receive user selections via a keyboard, mouse, touch pad, touch screen, etc.

[0027] Figure 3 and Figure 4 is a schematic illustration of an example corrector system configured in accordance with the present invention to produce reduced thermal magnetic noise during use in a charged particle microscope system. For example, Figure 3 The invention discloses S / C C An example Cc correction element of the corrector system 300. Specifically, Figure 3 Instance C S / C C The corrector system 300 is shown to include a magnetic multipole 302 surrounding an electrostatic quadrupole formed by a plurality of electrodes 304 .

[0028] Figure 3 A cross-sectional view of an electrode 304 is depicted, illustrating that the electrode 304 is individually formed of an inner core 306 composed of an electrically insulating material (e.g., a ceramic material, a vitreous material, quartz, a semiconductor material, etc.) and an outer coating 308 composed of a conductive material that completely surrounds the inner core. The conductive material is selected so that the thickness of the outer coating ( t ) multiplied by the conductivity of the conductive material (σ) is less than 0.01 Ω -1 , 0.001 Ω -1 , and / or 0.0001 Ω-1 In various embodiments, outer coating 308 may be electrically grounded and / or may have a sheet resistance greater than 10 kΩ and / or greater than 100 kΩ. When charged particle beam 310 travels in proximity to electrode 302, the presence of outer coating 308 on electrode 302 causes the electrode 302 to be electrically grounded. S / C C The amount of thermomagnetic noise (ie, Johnson noise) generated by the corrector system 300 is reduced by at least 2×, 3×, or an order of magnitude compared to known optical elements. Figure 3 Also instance C S / C C The corrector system 300 is illustrated as including an optional barrier 312 that partially defines a vacuum region, in example C. S / C C The charged particle beam 310 travels through the vacuum region during operation of the corrector system 300. However, in other embodiments, this optional barrier 312 may be positioned so that the magnetic multipoles are enclosed within the vacuum region.

[0029] Figure 4 The invention discloses S / C C Example Cc correction element of the corrector system 400. Specifically, Figure 4 Instance C S / C C The corrector system 400 is shown to include a magnetic multipole 402 surrounding an electrostatic quadrupole formed by a plurality of electrodes 404 . Figure 4 A cross-sectional view of an electrode 404 is depicted illustrating that the electrode 404 is individually formed of an inner core 406 composed of an electrically insulating material (eg, a ceramic material, a vitreous material, quartz, a semiconductor material, etc.) and an outer coating 408 composed of an electrically conductive material that completely surrounds the inner core. Figure 4 Embodiments are depicted where the outer core 408 does not completely surround the inner core 406. For example, in certain embodiments, h : g The ratio may be greater than 5 or 6. The conductive material is selected so that the product of the thickness (t) of the outer coating and the conductivity (σ) of the conductive material is less than 0.01 Ω -1 , 0.001 Ω -1 , and / or 0.0001 Ω -1 In various embodiments, outer coating 408 may be electrically grounded and / or may have a sheet resistance greater than 10 kΩ and / or greater than 100 kΩ. When charged particle beam 410 travels in proximity to electrode 402, the presence of outer coating 408 on electrode 402 causes the electrode 402 to be electrically grounded. S / C C The amount of thermomagnetic noise (ie, Johnson noise) generated by the corrector system 400 is reduced by at least 2×, 3×, or an order of magnitude compared to known optical elements.

[0030] Figure 5 A graphical relationship illustrating the contribution of thermal magnetic field noise (Johnson noise) to the TEM contrast transfer function (CTF) for both an existing system using current technology and a system incorporating technology from the present disclosure. Specifically, Figure 5 For example C C / C S Graph of the corrector system illustrating the contribution of Johnson noise to the CTF, the example C C / C S The corrector system consists of two four-pole Wien filters as C C Correction elements. These two elements use the main contribution of the objective lens to correct the axial chromatic aberration C of all other lenses. C Curve 502 corresponds to this example C constructed according to the prior art. C / C S The contribution of Johnson noise to the CTF for the first version of the corrector system. Curve 504 corresponds to an example C constructed to incorporate techniques from the present disclosure. C / C S Contribution of Johnson noise to the CTF for the second version of the corrector system.

[0031] When the two instances C C / C S Corrector System To evaluate the contribution of thermal magnetic field noise to the TEM CTF, we consider the common and ideal case where there are two perpendicular line foci of equal length in the center of these quadrupole Wien filters. We further consider a case with a half-opening angle in the sample plane. α x The effective focal length can then be Defined as The Johnson noise generated by the two four-pole Wien filters results in a Gaussian image spread in the sample plane, with an rms value σ given by:

[0032]

[0033] in = Relativistic Electron Voltage= ,and L and R = the length and inner radius of the four-pole Wien filter. In addition, the constant Defined as:

[0034]

[0035] When the system is at room temperature, it is equal to (in SI units); is the Boltzmann constant. In addition, for non-magnetic metals, the dimensionless constant , and for soft magnets, it is approximately equal to .

[0036] Figure 5 The curve 502 in FIG. 5 depicts the curve obtained from the experiment with two C C C of the correction element C / C S The contribution of the thermal magnetic field noise of the corrector system is a correction element having a and The quadrupole voltage between the magnetic multipoles. This allows equation (2) to be evaluated as:

[0037]

[0038] in , which represents the image diffusion caused by thermal magnetic field noise according to the parameters of a four-pole Wien filter. It may be obvious to those skilled in the art that the geometric parameters of this element are L and R does not appear in Equation 3 (because these dimensions affect the Johnson noise contribution). However, it should be noted that it does not exist because L and R The effect of the parameter on the magnification ratio between the corrector system and the objective (i.e., it affects the required chromatic aberration correction) ) causes these parameters to drop out of equation 3. In a four-pole Wien filter according to the invention, the magnetic multipoles can have a larger radius R , resulting in less Johnson noise. For the parameters of this magnetic multipole, the Johnson noise rms value σ is given by:

[0039]

[0040] in ,and is the inner radius of the magnetic multipole R The maximum magnetic field at . Equation 4 is used to calculate curve 504. The contribution of Johnson noise to the TEM contrast transfer function (CTF) is given by:

[0041]

[0042] in k is the spatial frequency.

[0043] According to this disclosure, Figure 5, curve 504 is for C including magnetic quadrupole and electrostatic quadrupole C / C S The corrector system shows the contribution of Johnson noise to the CTF. Equations 4 and 5 are used to calculate curve 504, where the parameters C C =1.6 mm, U=300 kV, R =6 mm, and = 0.04 Tesla. The Johnson noise generated by the internal electrodes is assumed to be negligible.

[0044] Curve 502 shows the relationship for the first case, where C C The electrodes of the correction element do not individually consist of an inner core of electrically insulating material and an outer coating of electrically conductive material. Usually less than 10kV is chosen. Using equations 3 and 5, for C C = 1.6 mm and = 6 kV calculation curve 502.

[0045] Examples of inventive subject matter according to the present disclosure are described in the following enumerated paragraphs.

[0046] A1. A corrector system with reduced Johnson noise generation, the corrector system comprising: an outer magnetic multipole; an inner electrostatic multipole, wherein components of the inner electrostatic multipole include: an inner core composed of an electrically insulating material; and an outer coating composed of an electrically conductive material.

[0047] A1.1. A corrector system according to paragraph A1, wherein the electrically insulating material comprises a semiconductor material.

[0048] A1.2. A corrector system according to paragraph A1, wherein the electrically insulating material comprises a ceramic material.

[0049] A2. A corrector system according to paragraph A1, wherein the outer coating completely surrounds the inner core.

[0050] A3. A calibrator system according to any of paragraphs A1 to A2.1, wherein the component is an electrode.

[0051] A4. A corrector system according to any of paragraphs A1 to A3, wherein the internal electrostatic multipole comprises a plurality of electrodes.

[0052] A4.1. A corrector system according to paragraph A4, wherein each of the plurality of electrodes comprises: an inner core composed of an electrically insulating material; and an outer coating composed of a conductive material.

[0053] A5. A corrector system according to any one of paragraphs A1 to A4.1, wherein the corrector is C c Corrector.

[0054] A6. A corrector system according to any one of paragraphs A1 to A4.1, wherein the corrector is C c / C s Corrector.

[0055] A6.1. A corrector system according to any one of paragraphs A1 to A4.1, wherein the corrector is C S Corrector.

[0056] A7. A corrector system according to any of paragraphs A1 to A6, wherein the outer coating has a sheet resistance greater than 10 kΩ.

[0057] A7.1. A corrector system according to paragraph A7, wherein the outer coating has a sheet resistance greater than 100 kΩ.

[0058] A8. A calibrator system according to any one of paragraphs A1 to A7.1, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.01 Ω -1 .

[0059] A8.1. A calibrator system according to paragraph A8, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.001 Ω -1 .

[0060] A8.2. A calibrator system according to paragraph A8, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.0001 Ω -1 .

[0061] A9. A corrector system according to any of paragraphs A1 to A7.1, wherein the outer coating causes a reduction in Johnson noise by 2×, 3×, or an order of magnitude.

[0062] A9.1. A corrector system according to paragraph A9, wherein the outer coating causes a reduction in Johnson noise of more than 2×, 3×, or an order of magnitude.

[0063] A10. A corrector system according to any of paragraphs A1 to A9.1, wherein the outer coating is electrically grounded.

[0064] B1. An electron microscope optical element with reduced Johnson noise generation, the optical element comprising: an inner core composed of an electrically insulating material; and an outer coating composed of an electrically conductive material.

[0065] B1.1. An optical element according to paragraph B1, wherein the electrically insulating material comprises a semiconductor material.

[0066] B1.2. An optical element according to paragraph B1, wherein the electrically insulating material comprises a ceramic material.

[0067] B2. An optical element according to paragraph B1, wherein the outer coating completely surrounds the inner core.

[0068] B3. An optical element according to any of paragraphs B1 to B2.1, wherein the optical element is an electrode.

[0069] B5. An optical element according to any of paragraphs B1 to B4.1, wherein the optical element is a corrector.

[0070] B5.1. An optical element according to paragraph B5, wherein the optical element is C c Corrector.

[0071] B5.2. An optical element according to any one of paragraphs B5 to B5.1, wherein the optical element is C c / C s Corrector.

[0072] B5.3. An optical element according to any of paragraphs B5 to B5.2, wherein the optical element further includes at least one external magnetic multipole.

[0073] A5.4. A corrector system according to any one of paragraphs B1 to B5, wherein the corrector is C S Corrector.

[0074] B7. An optical element according to any of paragraphs B1 to B5.4, wherein the outer coating has a sheet resistance greater than 10 kΩ.

[0075] B7.1. An optical element according to paragraph B7, wherein the outer coating has a sheet resistance greater than 100 kΩ.

[0076] B8. An optical element according to any of paragraphs B1 to B7.1, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.01 Ω-1.

[0077] B8.1. An optical element according to paragraph B8, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.001 Ω -1 .

[0078] B8.2. An optical element according to paragraph B8, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.0001 Ω -1 .

[0079] B9. An optical element according to any of paragraphs B1 to B7.1, wherein the outer coating causes a reduction in Johnson noise by 2×, 3×, or an order of magnitude.

[0080] B10. An optical element according to any of paragraphs B1 to B9, wherein the outer coating is electrically grounded.

[0081] C1. Use of a corrector system according to any one of paragraphs A1 to A10.

[0082] D1. Use of an optical element according to any one of paragraphs B1 to B10.

[0083] E1. A charged particle microscope system configured to have reduced thermal magnetic noise, the system comprising: a charged particle source configured to emit a charged particle beam toward a sample; a focusing column configured to guide the charged particle beam to the sample; a sample holder configured to hold the sample; a detector system configured to detect emission and / or charged particles based on the charged particle beam interacting with the sample; and a corrector system according to any one of paragraphs A1 to A10 and / or at least one of the optical elements described in any one of paragraphs B1 to B10.

[0084] F1. A use of the charged particle microscope system according to paragraph E1.

[0085] The systems, devices, and methods described herein should not be construed as limiting in any way. Indeed, the present disclosure is directed to all novel and non-obvious features and aspects of the various disclosed embodiments, either individually or in various combinations and sub-combinations formed with each other. The disclosed systems, methods, and devices are not limited to any specific aspect or feature or combination thereof, nor do the disclosed systems, methods, and devices require the existence of any one or more specific advantages or the resolution of any one or more specific problems. Any theory of operation is for ease of explanation, but the disclosed systems, methods, and devices are not limited to such theory of operation.

[0086] Although the operations of some of the disclosed methods are described in a specific sequential order for ease of presentation, it should be understood that unless the specific language stated below requires a specific order, this description encompasses rearrangement. For example, in some cases, the operations described in order may be rearranged or performed simultaneously. In addition, for simplicity, the accompanying drawings may not show the various ways in which the disclosed systems, methods, and devices can be used in combination with other systems, methods, and devices. In addition, the description content sometimes uses terms such as "determine", "identify", "produce", and "provide" to describe the disclosed methods. These terms are high-level abstractions of the actual operations performed. The actual operations corresponding to these terms will vary depending on the specific implementation, and are easily discerned by those skilled in the art.

Claims

1. An electron microscope optical element, the optical element comprising: an inner core composed of an electrically insulating material; as well as An outer coating layer composed of a conductive material, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating layer is less than 0.01Ω -1 , The electron microscope optical element is a deflector or an electrostatic multipole.

2. The optical element of claim 1, wherein the electrically insulating material comprises a ceramic material.

3. The optical element of claim 1, wherein the outer coating completely surrounds the inner core.

4. The optical element of claim 1, wherein the outer coating has a sheet resistance greater than 10 kΩ.

5. The optical element of claim 1, wherein the outer coating causes a reduction in Johnson noise by an order of magnitude.

6. A charged particle microscope system, the system comprising: a charged particle source configured to emit a charged particle beam toward the sample; a focusing column configured to direct the charged particle beam toward the sample; a sample holder configured to hold the sample; a detector system configured to detect emission and / or charged particles based on the charged particle beam interacting with the sample; as well as An electron microscope optical element having reduced Johnson noise generation, the optical element comprising: an inner core composed of an electrically insulating material; as well as an outer coating layer composed of a conductive material, wherein the outer coating layer has a sheet resistance greater than 10 kΩ, The optical element is a deflector or an electrostatic multipole.

7. The microscope system according to claim 6, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.01Ω -1 .

8. A corrector system, comprising: External magnetic multipoles; and An internal electrostatic multipole, wherein components of the internal electrostatic multipole include: an inner core composed of an electrically insulating material; and An outer coating layer composed of an electrically conductive material, wherein the outer coating layer has a sheet resistance greater than 10 kΩ.

9. The corrector system of claim 8, wherein the electrically insulating material comprises a semiconductor material.

10. The corrector system of claim 8, wherein the electrically insulating material comprises a ceramic material.

11. The corrector system of claim 8, wherein the outer coating completely surrounds the inner core.

12. The calibrator system of claim 8, wherein the component of the internal electrostatic multipole is an electrode, and the internal electrostatic multipole comprises a plurality of electrodes.

13. The calibrator system of claim 12, wherein each of the plurality of electrodes comprises: an inner core composed of an electrically insulating material; and An outer coating composed of a conductive material.

14. The calibrator system of claim 8, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating is less than 0.01Ω -1 .

15. A corrector system, comprising: External magnetic multipoles; and An internal electrostatic multipole, wherein components of the internal electrostatic multipole include: an inner core composed of an electrically insulating material; and An outer coating layer composed of a conductive material, wherein the product of the thickness (t) and the conductivity (σ) of the outer coating layer is less than 0.01Ω -1 .

16. The corrector system of claim 15, wherein the electrically insulating material comprises a semiconductor material.

17. The corrector system of claim 15, wherein the outer coating completely surrounds the inner core.

18. The calibrator system of claim 15, wherein the component of the internal electrostatic multipole is an electrode, and the internal electrostatic multipole comprises a plurality of electrodes.

19. The calibrator system of claim 18, wherein each of the plurality of electrodes comprises: an inner core composed of an electrically insulating material; and An outer coating composed of a conductive material.

20. The calibrator system of claim 15, wherein the outer coating has a sheet resistance greater than 10 kΩ.

21. A corrector system, the corrector system comprising: An internal electrostatic multipole formed by a plurality of electrodes, at least one of which comprises: a core composed of an electrically insulating material; and a coating of an electrically conductive material, the coating forming an outer layer of at least a portion of the electrode, wherein the coating is located between the core of the electrode and a charged particle beam and is maintained at a non-zero voltage when the corrector system is used in a charged particle system; and The outer magnetic multipole surrounds the inner electrostatic multipole.

22. The corrector system of claim 21, wherein the non-zero voltage is less than 10 kV.

23. The corrector system of claim 21, wherein the coating causes Johnson noise to be reduced by a factor of two.

24. The corrector system of claim 21, wherein the coating causes a reduction in Johnson noise by an order of magnitude.

25. The calibrator system of claim 21, wherein each electrode of the plurality of electrodes comprises: a core composed of an electrically insulating material; and a coating composed of a conductive material, the coating forming an outer layer of at least a portion of each electrode.

26. The corrector system of claim 21, wherein the electrically insulating material comprises a semiconductor material.

27. The corrector system of claim 21, wherein the electrically insulating material comprises a ceramic material.

28. The calibrator system of claim 21, wherein the product of the thickness (t) and the conductivity (σ) of the coating is less than 0.01Ω -1 .

29. A corrector system, the corrector system comprising: An internal electrostatic multipole formed by a plurality of electrodes, wherein a first electrode of the plurality of electrodes comprises: a core comprised of an electrically insulating material and having (i) an inner side capable of facing toward a beam path of a charged particle system and (ii) a lateral side adjacent to the inner side and not facing toward the beam path when the inner side is facing toward the beam path, the lateral sides being separated by a distance (g) between a second electrode of the plurality of electrodes; and a coating of an electrically conductive material, said coating forming an outer layer of at least a portion of said first electrode, said portion comprising said inner side and a length (h) along said lateral sides adjacent to said inner side, wherein said coating on said inner side is located between said core of said first electrode and a charged ion beam along a beam path when said corrector system is used in a charged particle system; and The outer magnetic multipole surrounds the inner electrostatic multipole.

30. The corrector system of claim 29, wherein a ratio of the length (h) to the distance (g) is greater than 5.

31. The corrector system of claim 29, wherein a ratio of the length (h) to the distance (g) is greater than 6.

32. The corrector system of claim 29, wherein the second electrode comprises: a second core comprised of an electrically insulating material and having (i) a second inner side capable of facing the beam path and (ii) a second lateral side adjacent to the second inner side and not facing the beam path when the second inner side faces the beam path, the second lateral side being separated by a distance (g) between the lateral sides of the first electrode; and A second coating composed of a conductive material, the second coating forming a second outer layer of at least a second portion of the second electrode, the second portion including the second inner side and a length (l) along the second lateral side adjacent to the second inner side, wherein the second coating on the second inner side is located between the second core of the second electrode and the charged ion beam along the beam path when the corrector system is used in a charged particle system.

33. A corrector system according to claim 32, wherein the ratio of the length (l) and the distance (g) is greater than 5.

34. A corrector system according to claim 32, wherein the ratio of the length (l) and the distance (g) is greater than 6.

35. The corrector system of claim 32, wherein the length (h) and the length (l) are the same.

36. The corrector system of claim 29, wherein the coating causes Johnson noise to be reduced by a factor of two.

37. The corrector system of claim 29, wherein the coating causes a reduction in Johnson noise by an order of magnitude.

38. The calibrator system of claim 29, wherein the coating has a sheet resistance greater than 10 kΩ.

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