Aberration correction system and charged particle microscope system including same

Abstract

An aberration correction system and a charged particle microscope system including the aberration correction system are provided herein. An apparatus may include a charged particle source and a light column. The light column may include a multipole concentrator having one or more concentrator quadrupole generating elements and / or a multipole objective having a plurality of objective multipole elements. The plurality of objective multipole elements may include at least three quadrupole generating elements and at least three octopole generating elements configured to at least partially correct for spherical aberration of the charged particle beam. The beam may be configured such that the charged particle beam enters the multipole objective with a non-circular beam profile and / or such that the charged particle beam is characterized by a non-circular beam profile through at least a portion of the multipole objective.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application S / N 18 / 478,971, filed on September 29, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to charged particle microscope systems, and in particular to charged particle microscopes having systems for correcting spherical and / or chromatic aberrations in charged particle beams. Background Art

[0004] Particle optical microscopy uses circular lenses to direct electron / charged particle beams to illuminate samples. However, such circular lenses produce positive spherical and chromatic aberration coefficients, which limit higher aperture angles and inhibit resolution and probe current. Summary of the invention

[0005] In one representative example, an apparatus includes a charged particle source configured to emit a charged particle beam and an optical column configured to direct the charged particle beam toward a sample. The optical column includes a multipole condenser having one or more condenser quadrupole generating elements and a multipole objective having a plurality of objective multipole elements. The plurality of objective multipole elements include at least three quadrupole generating elements and at least three octopole generating elements. The octopole generating element of the multipole objective is configured to at least partially correct a spherical aberration of the charged particle beam.

[0006] In another representative example, an apparatus includes a charged particle source configured to emit a charged particle beam and an optical column configured to direct the charged particle beam toward a sample. The optical column includes a multipole objective having a plurality of objective multipole elements. The plurality of objective multipole elements include at least three quadrupole generating elements and at least three octopole generating elements. The optical column is configured so that the charged particle beam enters the multipole objective with a non-circular beam profile. The octopole generating element of the multipole objective is configured to at least partially correct a spherical aberration of the charged particle beam.

[0007] In another representative example, an apparatus includes a charged particle source configured to emit a charged particle beam and an optical column configured to direct the charged particle beam toward a sample. The optical column includes a multipole condenser having one or more condenser quadrupole generating elements and a multipole objective having a plurality of objective multipole elements. The plurality of objective multipole elements include at least three quadrupole generating elements. The optical column is configured such that the charged particle beam is characterized by a non-circular beam profile passing through at least a portion of the multipole objective, and the optical column is configured to at least partially correct for spherical aberration of the charged particle beam.

[0008] The foregoing and other objects, features and advantages of the disclosed technology will become more apparent from the following detailed description made with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic side elevation view of a charged particle microscope system according to one example.

[0010] Figure 2 is a front elevation view of an electrostatic hexapole generating element according to one example.

[0011] Figure 3 is a schematic side elevation view of an aberration correction system according to one example.

[0012] Figure 4 is a charged particle beam according to an example relative to Figure 3 Illustration of the fundamental rays of the collimated optical axis of an aberration correction system.

[0013] Figure 5 is a side perspective view of a corrector electrostatic prism according to one example.

[0014] Figure 6 is a side perspective view of an incident electrostatic prism according to one example.

[0015] Figure 7 is a partial cross-sectional side elevation view of a corrector electrostatic prism according to one example.

[0016] Figure 8 is another partial cross-sectional side elevation view of a corrector electrostatic prism according to one example.

[0017] Fig. 9 is another partial cross-sectional side elevation view of a corrector electrostatic prism according to one example.

[0018] Fig.10 is another partial cross-sectional side elevation view of a corrector electrostatic prism according to one example.

[0019] Fig.11 is a schematic side elevation view of an aberration correction system according to another example.

[0020] Fig.12 is a schematic side elevation view of an aberration correction system according to another example.

[0021] Fig.13 is a schematic side elevation view of an aberration correction system according to another example.

[0022] Fig.14 Based on an example of Fig.13 Illustration of the aberration correction system for a fundamental ray of a charged particle beam.

[0023] Fig.15 is a schematic side elevation view of an aberration correction system according to another example.

[0024] Fig.16 is an aberration correction system according to an example and through Fig.15 Schematic diagram of the aberration correction system for the elementary ray of a charged particle beam.

[0025] Fig.17 According to another example, an aberration correction system and a Fig.15 Schematic diagram of the aberration correction system for the elementary ray of a charged particle beam.

[0026] Fig.18 is a schematic side elevation view of a charged particle microscope system according to one example.

[0027] Fig.19 is a schematic diagram of a charged particle microscope system and elementary rays of a charged particle beam passing through the charged particle microscope system according to an example, wherein chromatic aberration and third-order aberration are corrected.

[0028] Fig. 20 is a front elevation view of an electrostatic multipole element having four electrodes according to one example.

[0029] Fig.21 is a front elevation view of an electrostatic multipole element having eight electrodes according to one example.

[0030] Fig. 22 is a schematic diagram of a charged particle microscope system and elementary rays of a charged particle beam passing through the charged particle microscope system according to an example, wherein third order aberrations are corrected and the charged particle microscope system is operated at a first magnification.

[0031] Fig.23 Based on an example Fig. 22 Schematic diagram of a charged particle microscope system and a fundamental ray of a charged particle beam passing through the charged particle microscope system, wherein third-order aberrations are corrected and the charged particle microscope system is operated at a second magnification.

[0032] Fig.24 is a schematic diagram of another charged particle microscope system and elementary rays of a charged particle beam passing through the charged particle microscope system according to an example, wherein third order aberrations are corrected and the charged particle microscope system is operated at a first magnification.

[0033] Fig.25 Based on an example Fig.24Schematic diagram of a charged particle microscope system and a fundamental ray of a charged particle beam passing through the charged particle microscope system, wherein third-order aberrations are corrected and the charged particle microscope system is operated at a second magnification.

[0034] Fig.26 is a side elevation view of a first charged particle beam and a second charged particle beam focused to a common location on a sample according to an example.

[0035] Fig. 27 is a front elevation view of an electrostatic multipole element having eight electrodes formed as a micro-electromechanical system according to one example.

[0036] Fig.28 is a front elevation view of an electrostatic multipole element having eight electrodes with electrode extensions extending in a first lateral direction or a second lateral direction according to one example.

[0037] Fig.29 is a front elevation view of an electrostatic multipole element having eight electrodes, each of which is a member of a first shape electrode subset or a second shape electrode subset, according to an example.

[0038] Fig.30 is a front elevation view of an electrostatic multipole element having eight electrodes, each of which is a member of a first shape electrode subset or a second shape electrode subset, according to another example.

[0039] Fig.31 is a cross-sectional side elevation view of an apparatus according to one example, the apparatus comprising a plurality of electrostatic multipole elements configured to be included in a first angular envelope.

[0040] Fig.32 is a cross-sectional side elevation view of an apparatus according to one example, the apparatus comprising a plurality of electrostatic multipole elements and a lens housing configured to be included within a first angular envelope.

[0041] Fig.33 is a cross-sectional side elevation view of an apparatus according to an example, the apparatus comprising a plurality of electrostatic multipole elements configured to be included in a second angular envelope.

[0042] Fig.34 is a cross-sectional side elevation view of an apparatus according to one example, the apparatus comprising a plurality of electrostatic multipole elements and a lens housing configured to be included within a second angular envelope. DETAILED DESCRIPTION

[0043] Charged particle beam systems, such as scanning electron microscopes and focused ion beam microscopes, are widely used in the semiconductor and nanotechnology industries to image, manufacture and / or modify microscopic structures, such as by irradiating such structures with a charged particle beam (e.g., an electron beam or an ion beam). Such beam systems typically utilize electromagnetic lenses to converge, deflect and focus the charged particle beam onto a sample. Like optical systems, charged particle beam systems introduce axial aberrations that increase the size of the charged particle beam spot on the sample, thereby limiting the spatial resolution of the system.

[0044] Specifically, the focusing lens (also called the objective lens) positioned closest to the sample contributes most to the axial aberrations of the aperture, such as chromatic aberration and spherical aberration (denoted Cc and Cs, respectively). As O. Scherzer, " According to the publication "Einige FehlervonElektronenlinsen," Z. Physik 101, 1936, electromagnetic circular lenses always produce positive chromatic aberration and spherical aberration coefficients, so that a circular lens cannot completely compensate the aberration of another circular lens.

[0045] In addition, in another publication by the same author (O. Scherzer, " und chromatische Korrektur von Elektronenlinsen,” Optik 2, 1947, p. 114), it was shown that the aberration of a circular electromagnetic lens can be compensated by the negative aberration generated by a multipole. The multipole element includes N poles (e.g., electrodes) and is configured to generate an electrostatic or magnetic multipole field with ≤N times rotational symmetry. Therefore, the multipole element can generate (a combination of) a dipole field, a sextupole field, an octupole field, etc.

[0046] An example of a current solution for correcting chromatic aberration and spherical aberration of electron lenses was recently proposed in "Magnetic Cc / Cs-corrector compensating for the chromatic aberration and the spherical aberration of electron lenses" (H. Rose, A. Nejati, H. Müller, Ultramicroscopy 203, 2019, pp. 139-144, hereinafter referred to as Rose et al., 2019), where a purely magnetic corrector was introduced in detail. Specifically, the authors describe a bent axis corrector that includes magnetic quadrupole and sextupole generating elements arranged in an Ω-shaped design.

[0047] As mentioned in Rose et al., 2019, the quadrupole is configured for focusing and beam forming, while the sextupole is tuned in a way to counteract the positive chromatic aberration of the electro-optical system. Because the first-order rays are very astigmatic inside the corrector, an octopole can be added at appropriate locations so as to also correct for spherical aberration. The all-magnetic imaging corrector is intended for implementation in electron microscopes such as transmission electron microscopes (TEMs), and is specifically configured to correct chromatic and spherical aberrations for beam energies up to 1.2 MeV. However, the Cc / Cs corrector of Rose et al., 2019 utilizes only magnetic fields, and is therefore not practical for ions, as ions heavier than electrons are less sensitive to magnetic fields.

[0048] Alternatively, purely electrostatic Cc / Cs correctors can be used for both electron and ion beams with straight axes, as described, for example, in U.S. Patent Application Publication 2004 / 0051985, but such correctors are complex and the beam energy is very low (up to 8 kV), so ion-ion interactions are problematic.

[0049] Recently, the company CEOS / JEOL developed an electrostatic corrector suitable for beam energies up to 30 keV (https: / / www.ceos-gmbh.de / en / research / electrostat). However, the proposed corrector leads to major disadvantages, such as the generation of large higher-order aberrations and a high sensitivity to alignment errors due to the very strong focusing power of the Cc correction element. Therefore, the corrector proposed by CEOS / JEOL is only suitable for ion optics.

[0050] Examples of the disclosed technology seek to mitigate and / or overcome the shortcomings and deficiencies of existing aberration correction systems. More specifically, examples herein may include an improved system for correcting axial aberrations of a charged particle beam system.

[0051] Examples of the disclosed technology may also include correctors for axial chromatic aberration and / or spherical aberration, such as purely electrostatic correctors that compensate for chromatic aberration and / or spherical aberration of a charged particle beam system.

[0052] Figure 1 An example of a charged particle microscope system 100 that may include and / or utilize an aberration correction system as disclosed herein is shown. Figure 1 In the example of , the charged particle microscope system 100 is configured to direct or focus the charged particle beam 104 on the sample 132 to inspect and / or analyze one or more characteristics of the sample 132. The charged particle microscope system 100 may include and / or may be any of a variety of systems, such as an electron microscope (EM) equipment or electron lithography equipment configured to irradiate and / or otherwise impinge the sample 132 with the charged particle beam 104.

[0053] In various examples, the charged particle microscope system 100 may include and / or may be one or more different types of EM and / or charged particle microscopes, examples of which include a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), a transmission electron microscope (TEM), a charged particle microscope (CPM), a dual beam microscope system, etc. Additionally, in some examples, the TEM may also be capable of operating as a STEM. Figure 1 In the examples, the charged particle microscope system 100 is a SEM or a FIB system.

[0054] like Figure 1 As shown, the example charged particle microscope system 100 includes a charged particle source 102 (e.g., a thermal electron source, a Schottky emission source, a field emission source, a liquid metal ion source, a plasma ion source, etc.) that emits a charged particle beam 104 along an emission axis 106 and toward a condenser optical device 108. The condenser optical device 108 may include an electrostatic gun lens, an accelerator, and / or one or more condenser lenses. The emission axis 106 may be a central axis extending from the charged particle source 102 and through the sample 132 along the length of the example charged particle microscope system 100. Additionally or alternatively, the emission axis 106 may refer to and / or include a portion of a path followed by the charged particle beam 104 that extends proximate to the charged particle source 102.

[0055] The accelerator lens of the condenser optics 108 accelerates / decelerates, focuses, and / or directs the charged particle beam 104 toward a focusing column 110. As used herein, the focusing column 110 may additionally or alternatively be referred to as an optical column 110. The focusing column 110 focuses the charged particle beam 104 so that it is incident on the sample 132. Additionally, the focusing column 110 corrects and / or tunes aberrations (e.g., geometric aberrations, chromatic aberrations) of the charged particle beam 104.

[0056] like Figure 1 As shown, the focusing column 110 can be described as including, surrounding and / or defining an optical column axis 112 along which the charged particle beam 104 travels through at least a portion of the focusing column 110. In some examples, the emission axis 106 can be described as including the optical column axis 112. Although for simplicity Figure 1 The optical column axis 112 is shown as being straight, but this is not required and it is within the scope of the present disclosure that the optical column axis 112 may be curved.

[0057] like Figure 1 As shown, focusing column 110 may include an aberration correction system 120, as described in more detail below. Focusing column 110 may also include a transfer lens 122 and an objective lens 128.

[0058] The objective lens 128 is an optical device that focuses the charged particle beam 104 to a point (e.g., a well-defined point) on the sample 132. The objective lens 128 can produce a positive Cs. The objective lens 128 can include and / or can be any of a variety of focusing elements, examples of which include a single pole piece lens, a magnetic electrostatic compound lens, an electrostatic objective lens, or other types of objective lenses.

[0059] Figure 1 The charged particle microscope system 100 is also shown to include a sample holder 130 that holds a sample 132 and a detector 140 that is configured to detect charged particles 134 emitted from the sample 132 due to the charged particle beam 104 being incident on the sample 132. In addition, the charged particle microscope system 100 is shown to include astigmatism correction and scanning coils 126 for directing the charged particle beam 104 to scan the surface of the sample 132. For example, the scanning coils 126 can be configured to selectively change the direction of the charged particle beam 104 so that the charged particle beam 104 can be scanned across a region of the surface of the sample 132 to be probed (e.g., raster scanned).

[0060] like Figure 1 As shown, the charged particle microscope system 100 may also include one or more computing devices 150 programmed and / or configured to control the operation of one or more aspects of the charged particle microscope system 100. As an example, the computing device 150 may be programmed and / or configured to direct the charged particle beam 104 to a desired location on the sample 132, such as by translating the sample holder 130 and / or operating the scanning coil 126. Additionally or alternatively, the computing device 150 may be programmed and / or configured to receive a signal from the detector 140 to characterize the sample 132.

[0061] Those skilled in the art will appreciate that Figure 1 The computing device 150 depicted in the figure is merely illustrative and is not intended to limit the scope of the present disclosure. The computing device 150 may include and / or may be any combination of hardware or software that can perform the indicated functions, including a computer, a network device, an Internet appliance, a PDA, a wireless phone, a controller, an oscilloscope, an amplifier, etc. The computing device 150 may also be connected to other devices not shown (e.g., via wired and / or wireless communication connections), or may operate as a stand-alone system.

[0062] As discussed above, one or more components of a charged particle beam system (e.g., objective lens 128 of charged particle microscope system 100) may produce chromatic aberrations and spherical axial aberrations that limit the accuracy with which a charged particle beam can be focused on a sample. In order to illustrate the manner in which a correction system such as aberration correction system 120 can operate to correct such aberrations, the following discussion considers the origin and form of such aberrations. Although the following discussion is primarily presented in the context of electron beams, it should be understood that these principles can be applied to electron beams and ion beams, for example by introducing sign changes in some formulas. In the following discussion, calculations are performed with a non-relativistic approximation, which is suitable for ion beams and electron beams having electron energies representative of SEM systems (e.g., where eU≤30keV).

[0063] In the present disclosure, various properties of a charged particle beam may be described with reference to the rays that characterize the charged particle beam. Specifically, the systems described herein may be described as operating in a scheme in which the constituent particles of the charged particle beam travel along substantially straight paths, unless such paths are blocked, bent, and / or deflected by other components of the system. Therefore, many ray optics principles may be applied to such charged particle beams.

[0064] The spatial extent of a charged particle beam can be characterized with reference to any suitable coordinate system. In the present disclosure, the position of a portion of a charged particle beam (e.g., a portion of a ray) can be described with reference to an x-component as measured along the x-axis, a y-component as measured along the y-axis, a z-component as measured along the z-axis. In the present disclosure, the z-axis generally corresponds to the optical axis along which the charged particle beam travels, which may be a bending axis in some cases. The x-axis and y-axis may extend in any suitable direction so that the x-axis, y-axis, and z-axis are perpendicular to each other.

[0065] Multipolar

[0066] As used herein, the term "multipole element" may refer to any suitable component having a plurality of poles or electrodes to which corresponding voltages may be applied to generate a multipole field. For example, a multipole element having four poles may be configured to generate at least a quadrupole field. Similarly, a multipole element having six poles may be configured to generate at least a hexapole field. In the present disclosure, a multipole element may be named and / or described with reference to the multiplicity of the multipole field that the multipole element is configured to generate (e.g., as the primary or sole multipole field generated by the multipole element). For example, a "quadrupole generating element" may have four or more poles to generate at least a quadrupole field, and / or may have one or more poles shaped to generate at least a quadrupole field. Similarly, a "hexapole generating element" may have six or more poles to generate at least a hexapole field, and / or may have one or more poles shaped to generate at least a hexapole field.

[0067] In some examples, the multipole element may be additionally or alternatively configured to generate any of a plurality of multipole fields (and / or superpositions thereof). For example, in some examples, a hexapole generating element having six poles may be configured to generate a dipole field, a quadrupole field, and / or a hexapole field. Unless otherwise indicated, references herein to multipole fields (e.g., dipole fields, quadrupole fields, hexapole fields, octopole fields, etc.) generally refer to electrostatic multipole fields.

[0068] As an example, Figure 2 An example of an electrostatic hexapole generating element 200 is shown, which includes six electrodes 202, 204, 206, 208, 210, and 212 to which respective voltages V1, V2, ..., V6 may be applied. With one such hexapole generating element, dipole and quadrupole electrostatic fields of any orientation in the xy plane and / or a hexapole field of a fixed orientation may be generated.

[0069] We consider a Cc correction device in which the bend deflector optical axis lies in one plane, and we define the y-axis to be perpendicular to the plane. If we exclude the small multipole fields required to correct for mechanical error effects (i.e., neglect parasitic aberrations), all electrostatic multipole potentials are symmetric in y; that is, φ(x,y,z)=φ(x,-y,z), in which case the sextupole potential is given by φ3(x,y,z)=a3(z)(x 3 -3xy 2 )+fringe field terms.

[0070] Figure 2 An example is shown in which the electrostatic field generated by the hexapole generating element 200 can be tuned via selection of the voltage applied to each electrode. Specifically, if V1=V3=V5=V and V2=V4=V6=-V, a hexapole field is generated. Alternatively, if V1=V, V2=V / 2, V3=-V / 2, V4=-V, V5=-V / 2 and V6=V / 2, a dipole field E is generated. x , and if V1 = 0, V2 = V, V3 = V, V4 = 0, V5 = -v and V6 = -V, then a dipole field E is generated y Similarly, any linear combination of dipole, quadrupole, and / or hexapole fields may be generated. In other examples, and as discussed in more detail below, the shape of the electrodes of a multipole element may generate a multipole field of a fixed orientation corresponding to such shape.

[0071] Satisfy the symmetry condition φ m (x,y,z)=φ m The electrostatic multipole potential of multiplicity m at (x,-y,z) is given by

[0072]

[0073] The fringe field terms are not included, and where x = r cos(θ) and y = r sin(θ). The multiplicity m takes the value m = 1 for a dipole field, m = 2 for a quadrupole field, and so on. In the absence of symmetry conditions, equation (1) expands to

[0074]

[0075] First-order rays

[0076] The first-order rays of a charged particle beam (also called Gaussian rays) can be characterized by five ray parameters. One such parameter is the relative energy spread κ = ΔU / U. The remaining four parameters generally represent the orthogonal components of the position and angle of the ray in a given plane, such as the sample plane, z = z S The sample is located in the sample plane. Specifically, these parameters can be expressed as the x and y components of the ray in the sample plane, denoted as x s and s , and the angles of the x and y components of the ray in the sample plane, denoted as x′ s =α and y′ s =β. Ignoring the off-axis elementary ray components that are not very relevant to the probe forming system, the first-order ray can therefore be expressed as

[0077] x(z)=α·x a (z)+k·x κ (z) (3)

[0078] and

[0079] y(z)=β·y a (z), (4)

[0080] where x a (z) and y a (z) represents the axial ray, and x κ (z) represents a color scattered ray. Examples of such rays are Figure 4 It is shown in and discussed below.

[0081] Axial geometric aberration

[0082] The geometric axial aberration of a charged particle beam in the sample plane can be defined via the phase function S(α,β), where α = x′ = dx / dz and β = y′ = dy / dz. This function is characterized by the wavelength optical expression exp(i2πλ -1 S(α,β)), where λ is the charged particle wavelength. Without including parasitic aberrations, due to the symmetry of the electrostatic potential, S(α,β) contains only even powers of β and is therefore given by

[0083]

[0084]

[0085] If parasitic aberrations are included, an extension of formula (5) is required, where in addition to C1, C3≡C S All aberration coefficients except C5 are complex. For example, coma B 2r and triple astigmatism A 2r The term expands to

[0086]

[0087] Where B2 = B 2r +iB 2i , A2=A 2r +iA 2i , ω=α+iβ, and The third-order aberrations are spherical aberration C3, stellar aberration S 3r (which is twice) and four times the astigmatism A 3r The position aberration in the sample plane is given by and The equivalent formula in complex notation is For example, the second-order aberration is given by

[0088]

[0089]

[0090] In these formulas, the <.|..> symbol is used to represent aberration coefficients that do not have well-established signs. For example, in an expression of the form δx = c1α 2 +c2β 2 In the equation, the coefficient can be expressed as c1= <x|α 2 > and c2= <x|β 2 >.

[0091] Off-axis geometric aberrations

[0092] Although geometric axial aberrations are particularly relevant to the formation of a charged particle beam by the probe, off-axis aberrations are also relevant. For example, off-axis aberrations can determine the sensitivity of components of a charged particle microscope to drift of the incident charged particle beam. In addition, for sufficiently small off-axis aberrations, it may be advantageous to perform alternating current (AC) scanning upstream of the part of the aberration correction system.

[0093] All geometric aberrations can be conveniently obtained by perturbing the optical path function S(α, β, x S ,y S ) description, where the additional ray parameter x S andS Limited to the sample surface z = z S The function S(α,β,0,0) is equal to the phase function S(α,β) expressed in formula (5).

[0094] and

[0095] remains valid; in addition, the angular aberration is given by

[0096] and

[0097] For correctors according to the present disclosure, second-order aberrations are the most relevant. (Ignoring parasitic aberrations, the corresponding image-side optical path is given by

[0098]

[0099]

[0100] It has five independent coefficients. The three off-axis aberration coefficients <.|..> give

[0101] δx= <x|αx S >αx S + <x|βy S >By S (12) and

[0102] δy= <y|βx S >βx S + <x|βy S >αy S (13)

[0103] Unless all three off-axis coefficients are zero, the beam will drift above the corrector (resulting in a non-zero x S and / or S ), which will therefore cause defocus and / or astigmatism, i.e., aberrations of first order in α and β. As a result of formula (10), the three off-axis aberration coefficients are determined via the angular aberration of the axial beam:

[0104]

[0105] therefore, and<y′|αβ> =- <x|βy S >.

[0106] The third-order off-axis aberrations may also be relevant; then for the intrinsic aberrations only, the corresponding term in the perturbation path function is related to α 3 x S , αβ 2 xS , α 2 βy S and β 3 y S In this case as well, the angular aberrations of the axial beam provide these off-axis aberrations. The mirror symmetry in the xz plane corresponds to the term A constraint that only occurs when n+m is even.

[0107] Chromatic Aberration

[0108] The axial chromatic aberration coefficient of the circular lens is C. c to characterize, with corresponding aberration

[0109] And δy=-C c βκ, (15)

[0110] where eU is equal to the electron energy. For the corrector according to the present disclosure, this is summarized as

[0111] δx=-C cx ακ and δy=-C cy βκ. (16)

[0112] Alternatively, in which C cx ≠C cy In the example, the color difference coefficient C can be used c =(C cx +C cy ) / 2 and chromatic astigmatism coefficient A 1κ,r =(C cx -C cy ) / 2=Re(A 1κ ), so generally speaking Where ω=α+iβ.

[0113] The corrector according to the present disclosure can be designed so that the charged particle beam leaving the corrector is completely free of dispersion. In other words, the chromatic dispersion line can coincide with the optical axis below the corrector so that the first degree of aberration<x|κ> and<x′|κ> Here it is zero, especially at the sample.

[0114] In the present disclosure, an aberration may be characterized by order and / or degree. Specifically, as used herein, the term "order" corresponds to the geometric part of the aberration, while the term "degree" refers to the power of κ in the aberration. For example, the chromatic aberration coefficient C c represents an aberration of the 1st order and degree 1. For another example, the spherical aberration coefficient C3 represents an aberration of the 3rd order and degree 0. In addition, as used herein, the term "order" represents the sum of the order and degree of an aberration.

[0115] Secondary aberration

[0116] For a perfect device, all relevant second-order aberrations can be derived from the image-side perturbation path function

[0117]

[0118] where the first row contains the axial aberration coefficients and where the second row contains the (geometric only) off-axis aberration coefficients. S ) and β=y′(z S ) represents the sample surface z = z S The ray angle in x S and S is the position coordinate in the sample plane, κ = ΔU / U represents the relative energy deviation, and the position aberration in the sample plane is given by and Given.

[0119] The secondary parasitic aberration can be expressed as

[0120]

[0121] The last three off-axis aberrations are usually negligible and need not be considered in the design of the corrector.

[0122] First order aberration

[0123] Besides parasitic defocus and astigmatism C1 and A1, which can be easily eliminated, first-degree parasitic dispersion is important:

[0124] S 1,par. =<x|κ> ακ+<y|κ> βκ (19)

[0125] δx=<x|κ> κ (20)

[0126] δy=<y|κ> κ (21)

[0127] Sextupole Field of Second-Order Aberration

[0128] In an ideal device, the sextupole field can affect the axial secondary aberration A 2r , B 2r , C cx , C cy and <x|κ 2 >. If necessary, an additional sextupole field can be applied to reduce or eliminate off-axis aberration coefficients <x|αy S >、 <y|βy S > and <x|βx S >one or more of so as to make the corrector insensitive to drift of the charged particle beam above the corrector.

[0129] For practical devices subject to parasitic aberrations, additional sextupole fields may be required to cancel A 2i and B 2i , preferably where x κ = 0. An additional sextupole field may also be needed to eliminate the chromatic astigmatism component A 1κ,i The corresponding sextupole potential is in the following form

[0130]

[0131] Aberrations caused by thin multipoles

[0132] For the position z=z M For a multipole element of relatively short length L, the sextupole potential of the multipole element in the sharp cutoff (SCOFF) approximation of the fringe field is given by

[0133] φ3=a3(x 3 -3xy 2 ) (twenty three)

[0134] This is for z M -L / 2 <z<z M +L / 2, and outside this region φ3 = 0. In other words, a3(z) is a "rectangular" or "top hat" function. The electrode voltage is roughly in the range ±a3R 3 where R is the inner radius of the multipole element. The electric field is given by and To achieve a good approximation, the hexapole field induces a small deflection angle

[0135] and

[0136]

[0137] And the sample surface z = z S The secondary aberration obtained in is given by

[0138] and

[0139]

[0140] where the lateral electron position (x,y) is given by

[0141] x(z)=α·x a (z M )+κ·x κ (z M )and

[0142] y(z)=β·y a (z M ). (26)

[0143] As an example, for the case where there is no dispersion (i.e., x κ (z M ) = 0) and the axial beam is circular (ie, x a (z M )=y a (z M )≡x a ) of z=z M The hexapole field at , then equations (25) and (26) yield

[0144] and

[0145] The astigmatism coefficient A in the sample plane is tripled 2r The real part of is given by

[0146]

[0147] Expand to x a (z M )≠y a (z M ) and where x κ (z M )=0, astigmatism A 2r and coma B 2r The result is

[0148] and

[0149] In general, for non-zero dispersion in thin multipole elements (i.e., x κ ≠0), the axial secondary aberration caused by the sextupole field is A 2r , B 2r , C cx , C cy , and second-degree dispersion <x|κ 2 >.

[0150] Chromatic aberration correction in the yz plane

[0151] In many examples, the corrector mid-plane z = z mid Basic ray x a (z mid )=0, and y a (z mid ) and x κ (z mid ) is larger there. In this example, C in the yz plane cThe correction is preferably performed using a tunable hexapole generating element in the corrector intermediate plane. Assuming that the radius R of all electrostatic prisms is 棱镜 Equal, x κ (z mid )=g1R 棱镜 , where for the α-type corrector discussed below, |g1| ≈ 2, and for the Ω-type corrector discussed below, |g1| ≈ 3. In the sample plane, combining equations (22) and (23) yields

[0152]

[0153] where y a =y a (z mid ) and x κ =x κ (z mid ). Referring to formula (16), it can be seen that

[0154]

[0155] where the sign is determined by the sextupole polarity (i.e., the sign of a3). Therefore, the intermediate plane sextupole field can eliminate the C cy .

[0156] In the xz plane, the midplane hexapole field induces an angle

[0157]

[0158] This does not result in a positional aberration δx, since the intermediate surface is imaged onto the specimen surface in the xz plane, but the second term ∝β 2 ) does lead to angular aberrations of the axial beam, which translates into off-axis aberrations as outlined above. The corresponding aberration coefficients are <y|βx s >; Optical path function Get the sample surface and δy= <y|βx s >βx s Accordingly, if the charged particle source drifts in (for example) the x-direction, this results in defocus in the yz plane. In some examples, this off-axis aberration can be eliminated, such as by focusing the image in a position where there is little or no dispersion (i.e., in the x-direction). κ In the case of a smaller case) in a similar line focus (i.e., in x a =0) a hexapole field is applied.

[0159] Chromatic aberration correction in the xz plane

[0160] In some examples, chromatic aberration correction in the xz plane is performed with two hexapole fields positioned at z=z Aand z = z C At the two line foci of a (z A )=y a (z C )=0. In addition, in this example, x κ (z A )=x κ (z C )≡x κ And x a (z A )--x a (z C )≡x a . C cx The pure correction of requires symmetrical excitation of two sextupole fields, but the treatment of the sextupole excitation is z = z A a3+∈ and z=z C The general case of a3-∈ at θ is useful. These sextupole fields are only x Causes deflection: and Therefore, the total position aberration in the specimen plane is given by

[0161]

[0162] For symmetric excitation (ie, ∈ = 0), there is only one aberration:

[0163]

[0164] Equation (34) shows that the second degree dispersion can be tuned using asymmetric excitation <x|κ 2 >, but this excitation will also produce second-order aberrations <x|α 2 >, which must be compensated elsewhere. This compensation can also be performed at another location of the line focus of the charged particle beam, where again y a = 0, and there is little to no dispersion, i.e., where x κ ≈0. In such an example, the sextupole field in the line focus may primarily or exclusively generate the balanced aberration coefficient <x|α 2 >.

[0165] Such a sextupole field can also lead to aberration coefficients with corresponding <x|αx S >Off-axis aberration. Optical path function Get the sample surface and δx= <x|αx S >αx S Both. This off-axis aberration does not occur in the Ω-type example discussed below, because the correction C cxThe two sextupole fields are imaged onto each other not only in the yz plane, but also in the xz plane, so that the second-order geometric aberrations completely cancel each other out.

[0166] Chromatic Aberration Corrector Example

[0167] Figure 3 An aberration correction system 300 is shown for at least partially correcting axial chromatic aberration of a charged particle beam 302. The aberration correction system 300 may be described as representing Figure 1 Similarly, the charged particle beam 302 may include and / or may be Figure 1 A charged particle beam 104 is provided.

[0168] like Figure 3 As shown, the aberration correction system 300 includes a deflector assembly 310, which includes a corrector electrostatic prism 312 and a plurality of electrostatic multipole elements 314. Figure 3 As shown, the deflector assembly 310 can define a deflector optical axis 308 such that when the charged particle beam 302 passes through the aberration correction system 300, the charged particle beam 302 travels along the deflector optical axis 308. The deflector assembly 310 can therefore be configured to at least partially correct axial chromatic aberration in the charged particle beam 302 as the charged particle beam 302 travels along the deflector optical axis 308. Figure 3 In the example of FIG. 3 , the deflector optical axis 308 is a curved axis that is circular within the corrector electrostatic prism 312. The circular path of the deflector optical axis 308 within the corrector electrostatic prism 312 can be determined by the prism radius R 棱镜 to characterize, as measured between the central axis 301 of the corrector electrostatic prism 312 and the deflector optical axis 308.

[0169] The corrector electrostatic prism 312 can be configured to generate at least a portion of an electrostatic deflection field associated within the corrector electrostatic prism 312 that directs the charged particle beam 302 along the curved deflector optical axis 308. The electrostatic deflection field can include a prismatic hexapole field, such as can be generated by at least a subset of the plurality of electrostatic multipole elements 314.

[0170] like Figure 3 As shown, the aberration correction system 300 also includes: an incident electrostatic prism 304, which is configured to direct (e.g., deflect) the charged particle beam 302 from the optical axis 303 toward the deflector optical axis 308 and / or to the deflector optical axis; and an exit electrostatic prism 306, which is configured to direct (e.g., deflect) the charged particle beam 302 from the deflector optical axis 308, such as toward the optical axis 303 and / or to the optical axis. The optical axis 303 may represent Figure 1In this way, the optical column axis 303 can be described as excluding the deflector optical axis 308, so that the deflector optical axis 308 represents and / or includes the path of the portion of the charged particle beam 302 that is deflected away from the optical column axis 303.

[0171] The incident electrostatic prism 304 and the exit electrostatic prism 306 may each have any of a variety of structures and / or configurations for directing the charged particle beam 302 as described above. In some examples, each of the incident electrostatic prism 304 and the exit electrostatic prism 306 is configured to deflect the charged particle beam 302 by an angle equal to or approximately equal to 45 degrees. However, this is not required, and in addition, within the scope of the present disclosure, the incident electrostatic prism 304 and the exit electrostatic prism 306 may each deflect the charged particle beam 302 by an angle greater than or less than 45 degrees. Additionally or alternatively, in some examples, the incident electrostatic prism 304 and the exit electrostatic prism 306 may be configured to deflect the charged particle beam 302 by different amounts (e.g., by respective angles that are different from each other).

[0172] In some examples, one or both of the incident electrostatic prism 304 and the exit electrostatic prism 306 are dual-focus prisms. Additionally or alternatively, in some examples, one or both of the incident electrostatic prism 304 and the exit electrostatic prism 306 can be arranged in different planes (e.g., in the xz plane and the yz plane, such as Figure 3 The different focusing actions are shown in FIG.

[0173] In some examples, the incident electrostatic prism 304 and the exit electrostatic prism 306 can be configured to selectively direct the charged particle beam 302 to travel along the deflector optical axis 308 or alternatively bypass the corrector electrostatic prism 312 (e.g., continue to travel along the optical column axis 303). For example, the aberration correction system 300 can be configured to selectively operate in each of a correction mode and a direct axis mode, in which the incident electrostatic prism 304 directs the charged particle beam 302 toward the deflector optical axis 308, and in which the charged particle beam bypasses the deflector assembly 310. In some such examples, and as Figure 3 , the aberration correction system 300 can be configured such that when the aberration correction system 300 is in the direct axis mode, the charged particle beam 302 travels through each of the incident electrostatic prism 304 and the exit electrostatic prism 306 without deflection. This can be achieved, for example, by configuring each of the incident electrostatic prism 304 and the exit electrostatic prism 306 to include an aperture and / or a channel through which the charged particle beam 302 can pass without deflection when no deflection voltage is applied to each prism.

[0174] In the present disclosure, a particle beam (e.g., charged particle beam 104 and / or charged particle beam 302) may be described as traveling "along" a certain direction and / or axis (e.g., emission axis 106, optical column axis 112, optical column axis 303, and / or deflector optical axis 308), even when and / or at least a portion of the particle beam deviates from the direction and / or axis in space. For example, and as discussed herein, a particle beam may be characterized by a non-zero spatial range in a direction perpendicular to its direction of travel in at least a portion of the beam path of the particle beam. Therefore, in the present disclosure, the axis along which the particle beam travels may refer to a path surrounded and / or surrounded by the particle beam and / or a path that characterizes the average motion of the particles of the particle beam. Additionally or alternatively, the curved axis along which the particle beam travels may be defined as coinciding with the central axial ray of the particle beam; that is, the ray of the charged particle beam travels just along the straight optical axis upstream of the curved optical axis before being deflected onto the curved optical axis. In other words, the central axial ray can be described as representing the ray at the center of the axial beam cone.

[0175] In addition, in the present disclosure, the axis (e.g., the emission axis 106, the optical column axis 112, the optical column axis 303, and / or the deflector optical axis 308) characterizing the beam path of the particle beam (e.g., the charged particle beam 104 and / or the charged particle beam 302) can follow a curved trajectory. Figure 3 In the example of , the deflector optical axis 308 passing through the deflector assembly 310 can be described as α-shaped (i.e., shaped in a manner similar to the Greek letter α). Figure 3 In the example of , the portion of the deflector optical axis 308 extending within the corrector electrostatic prism 312 follows a circular path. In the present disclosure, any example of an aberration correction system and / or deflector assembly thereof characterized by a deflector optical axis being generally α-shaped may be referred to as an "α-type" system or assembly.

[0176] exist Figure 3 In the example of FIG. 5 , the plurality of electrostatic multipole elements 314 include a first hexapole generating element 320 , a second hexapole generating element 322 , a third hexapole generating element 324 , a first quadrupole generating element 330 , and a second quadrupole generating element 332 .

[0177] like Figure 3 As shown, at least a subset of the plurality of electrostatic multipole elements 314 (e.g., at least a first hexapole generating element 320, a second hexapole generating element 322, and a third hexapole generating element 324) may be at least partially positioned and / or incorporated within the corrector electrostatic prism 312. Specifically, although for clarity, Figure 3 Each electrostatic multipole element 314 is shown as partially overlapping the corrector electrostatic prism 312 , but it should be understood that each electrostatic multipole element may also be at least substantially and / or completely contained within the corrector electrostatic prism 312 .

[0178] In some examples, each of the first sextupole generating element 320, the second sextupole generating element 322, and the third sextupole generating element 324 includes six poles for generating a corresponding sextupole field (e.g., as a primary or sole multipole field). In other examples, one or more of the first sextupole generating element 320, the second sextupole generating element 322, and / or the third sextupole generating element 324 may include more than six poles (e.g., eight poles) to generate a small additional multipole field (e.g., a rotating sextupole field) to eliminate parasitic aberrations caused by mechanical errors. Additionally or alternatively, one or more of the electrostatic multipole elements 314 may be configured to generate a small dipole field and / or a small quadrupole field. Such a dipole field may be operable to align a central ray of the charged particle beam 302. Such a quadrupole field may be operable to align a first-order ray of the charged particle beam 302 (e.g., discussed below). Figure 4 basic rays shown).

[0179] In some examples, a quadrupole generating element (e.g., first quadrupole generating element 330 and / or second quadrupole generating element 332) of an aberration correction system according to the present disclosure may include four poles for generating a corresponding quadrupole field (e.g., as a primary or sole multipolar field). In other examples, a quadrupole generating element may include more or less than four poles.

[0180] In some examples, a multipole element of an aberration correction system according to the present disclosure may be configured to generate a corresponding multipole field due to the geometry and / or corresponding structure of the multipole element. For example, a portion of an electrostatic prism (e.g., corrector electrostatic prism 312, entrance electrostatic prism 304, and / or exit electrostatic prism 306) may be shaped so that applying a deflection voltage to the electrostatic prism generates a multipole field component in addition to the deflection electrostatic field.

[0181] For example, a multipole element that is primarily configured to generate a first type of multipole field (e.g., a quadrupole field) may include a pole that is shaped to additionally generate another type of multipole field (e.g., an octopole field, a 12-pole field, etc.). That is, although it is generally desirable to configure a multipole element to generate a corresponding multipole field that is as "pure" as possible (e.g., to generate a hexapole field with a minimum of quadrupole, octopole, etc. field components), it is also desirable to configure a single multipole element to generate a superposition of multiple multipole fields in other cases. In some examples, this can simplify the design of the system by enabling the use of fewer optical elements and / or applied voltages to generate a desired field.

[0182] In the present disclosure, such geometry-related multipole fields can be described as "fixed" and / or "static" in the sense that such fields have a type and / or orientation fixed by the geometry of the corresponding structure. Such fields may be additionally or alternatively referred to as "auxiliary fields" herein. The magnitude of such auxiliary fields can be changed by changing the voltage applied to the structure generating such auxiliary fields; however, since such voltages are usually applied to achieve different primary effects (e.g., the deflection of a charged particle beam along a well-defined direction and / or the generation of different primary multipole fields), the magnitude of the auxiliary fields is usually not independently variable. Therefore, the desired configuration of the auxiliary fields must usually be achieved by the careful shaping of the corresponding structures rather than by the control of the applied voltage.

[0183] In some examples, and as Figure 3 As shown, each of the first quadrupole generating element 330 and the second quadrupole generating element 332 can be configured to generate a corresponding auxiliary quadrupole field (e.g., as a primary or sole multipolar field). Specifically, each of the first quadrupole generating element 330 and the second quadrupole generating element 332 can be at least partially defined by the corrector electrostatic prism 312, such as via appropriate shaping of the corrector electrostatic prism 312, wherein the deflector optical axis 308 enters and exits the corrector electrostatic prism 312.

[0184] Each of the first hexapole generating element 320, the second hexapole generating element 322, and the third hexapole generating element 324 is primarily configured to generate a corresponding hexapole field, but may also generate small finely tuned dipole and / or quadrupole fields. Specifically, the first hexapole generating element 320 is configured to generate a first hexapole field, the second hexapole generating element 322 is configured to generate a second hexapole field, and the third hexapole generating element 324 is configured to generate a third hexapole field.

[0185] Similarly, each of the first quadrupole generating element 330 and the second quadrupole generating element 332 is primarily configured to generate a corresponding quadrupole field. Specifically, the first quadrupole generating element 330 is configured to generate a first quadrupole field, and the second quadrupole generating element 332 is configured to generate a second quadrupole field.

[0186] In the drawings of the present disclosure, electrostatic multipole elements (such as Figure 3The first hexapole generating element 320, the second hexapole generating element 322, and the third hexapole generating element 324 represent electrostatic multipole elements configured to generate corresponding multipole fields that are tunable (e.g., in orientation and / or magnitude). In such examples, the solid lines shown may additionally or alternatively be understood to represent corresponding tunable multipole fields. In such examples, and as described herein, such tunable multipole fields may be generated and / or configured in any of a variety of ways, such as by applying independently controllable voltages to corresponding poles of the multipole elements so as to generate a desired multipole field having one or more degrees of freedom.

[0187] Alternatively, in the drawings of the present disclosure, the electrostatic multipole elements (such as Figure 3 The first quadrupole generating element 330 or the second quadrupole generating element 332) represents an electrostatic multipole element configured to generate a corresponding auxiliary multipole field. In such examples, the dotted lines shown may be additionally or alternatively understood to represent a corresponding auxiliary multipole field. In such examples, and as described herein, such auxiliary multipole fields may be generated and / or configured in any of a variety of ways, such as by appropriate shaping of the electrodes of the associated multipole element.

[0188] like Figure 3 As shown, the charged particle beam 302, the optical column axis 303 and / or the deflector optical axis 308 can also be characterized with reference to the x-axis, the y-axis and the z-axis. Specifically, the z-axis can be defined as the direction along which the deflector optical axis 308 is oriented at a given position along the deflector optical axis 308. The x-axis can be defined as a direction perpendicular to the z-axis at a given position along the deflector optical axis 308 and extending within the plane in which the deflector optical axis 308 extends within the deflector assembly 310, and the y-axis can be defined as a direction perpendicular to each of the x-axis and the z-axis.

[0189] like Figure 3 As shown, the position and / or location of a portion of the deflector optical axis 308 extending within the corrector electrostatic prism 312 can be characterized by a prism angle φ, which can take the form of a zero and a maximum prism angle φ. max Specifically, the prism angle of φ=0 may correspond to the position where the charged particle beam 302 enters the corrector electrostatic prism 312 along the deflector optical axis 308, φ=φ max The prism angle φ may correspond to the position where the charged particle beam 302 leaves the corrector electrostatic prism 312 along the deflector optical axis 308. In this way, the angle φ max 312 may be described as representing the full angular range of the corrector electrostatic prism 312 and / or the total angle through which the charged particle beam 302 is deflected as it passes through the corrector electrostatic prism 312 .

[0190] Angle φmax Any of a plurality of values ​​may be used. Specifically, Figure 3 In the example, the angle φ max is equal to or approximately equal to 270 degrees. However, this is not required for all examples, and it is also within the scope of the present disclosure that the angle φ max It can be less than or greater than 270 degrees.

[0191] In various examples, and as Figure 3 As shown, the angle φ max The sum of the respective angles through which the incident electrostatic prism 304 and the exit electrostatic prism 306 deflect the charged particle beam 302 is equal to or approximately equal to 360 degrees, so that the charged particle beam 302 travels in substantially the same direction upstream and downstream of the deflector assembly 310. Thus, in some examples, the corrector electrostatic prism 312 can pass through the maximum prism angle φ max =250 degrees, and each of the incident electrostatic prism 304 and the exit electrostatic prism 306 can be configured to deflect the charged particle beam 302 through an angle of 55 degrees. Alternatively, in some other examples, the corrector electrostatic prism 312 can be configured to deflect the charged particle beam 302 through a maximum prism angle φ max =280 degrees, and each of the incident electrostatic prism 304 and the exit electrostatic prism 306 can be configured to deflect the charged particle beam 302 through an angle of 40 degrees.

[0192] The electrostatic multipole elements 314 of the deflector assembly 310 may have any of a variety of configurations relative to each other and / or relative to the corrector electrostatic prism 312. For example, and as Figure 3 As shown, the first quadrupole generating element 330 can be positioned between the incident electrostatic prism 304 and the first hexapole generating element 320 along the deflector optical axis 308, and the second quadrupole generating element 332 can be positioned between the third hexapole generating element 324 and the exit electrostatic prism 306 along the deflector optical axis 308.

[0193] exist Figure 3 In the example of FIG. 3 , the second hexapole generating element 322 is positioned adjacent to the midpoint of the deflector optical axis 308 within the corrector electrostatic prism 312. Specifically, in Figure 3 In the example, the corrector electrostatic prism 312 is max =270 degrees, so that the second hexapole generating element 322 is positioned and / or centered at a prism angle of φ=135 degrees.

[0194] In addition, Figure 3In the example of , each of the first hexapole generating element 320 and the third hexapole generating element 324 is angularly equidistant from the second hexapole generating element 322, so that the deflector assembly 310 is mirror-symmetric in the middle plane (i.e., about the center of the second hexapole generating element 322). Specifically, Figure 3 In the example of , the first hexapole generating element 320 is positioned and / or centered at a prism angle of approximately φ=58 degrees, while the third hexapole generating element 324 is positioned and / or centered at a prism angle of approximately φ=212 degrees. However, such an arrangement is not required, and further within the scope of the present invention, the first hexapole generating element 320 and the third hexapole generating element 324 may be positioned at any suitable respective prism angles, such as at prism angles corresponding to a position at or near the linear focus of the charged particle beam 302 within the corrector electrostatic prism 312.

[0195] Figure 4 Elementary rays x of a charged particle beam 400 are shown, respectively labeled 402, 404, and 406. a (z), y a (z) and x κ (z), the charged particle beam passes through an aberration correction system such as Figure 3 In other words, Figure 4 The charged particle beam 400 may include Figure 3 charged particle beam 302 and / or at least a portion thereof. Figure 4 shows the direction corresponding to Figure 3 The deflector optical axis 308 and / or the collimated optical axis 418 of the z-axis are provided. Figure 4 As shown, a charged particle source (eg, Figure 1 The charged particle source 102) is imaged onto the corrector inlet 408, and the corrector exit focus 410 is imaged onto the sample plane via appropriate optics. S A sample or specimen (e.g. Figure 1 On sample 132). Figure 4 In the example of FIG. 4 , such optical devices include a transfer lens 440 and an objective lens 442, which can be similar to Figure 1 transfer lens 122 and / or objective lens 128.

[0196] Figure 4 Also shown are the positions of first hexapole generating element 420 , second hexapole generating element 422 , third hexapole generating element 424 , first quadrupole generating element 430 , and second quadrupole generating element 432 relative to collimated optical axis 418 and relative to elementary rays 402 , 404 , and 406 . Figure 4The first hexapole generating element 420, the second hexapole generating element 422, the third hexapole generating element 424, the first quadrupole generating element 430 and the second quadrupole generating element 432 correspond to Figure 3 The first hexapole generating element 320 , the second hexapole generating element 322 , the third hexapole generating element 324 , the first quadrupole generating element 330 and the second quadrupole generating element 332 .

[0197] like Figure 4 As shown, the charged particle beam 400 exhibits line focusing at positions close to the first hexapole generating element 420 and the third hexapole generating element 424 in the xz plane, and exhibits line focusing at a position close to the second hexapole generating element 422 in the yz plane.

[0198] Figure 4 Also shown are the positions of the incident electrostatic prism 412, the exit electrostatic prism 414 and the corrector electrostatic prism 416, which correspond to Figure 3 The incident electrostatic prism 304, the exit electrostatic prism 306 and the corrector electrostatic prism 312.

[0199] Figure 3 The corrector electrostatic prism 312 and / or Figure 4 The corrector electrostatic prism 416 may have any suitable structure for deflecting the charged particle beam 302 and / or for supporting at least a subset of the plurality of electrostatic multipole elements 314. For example, Figure 5 An example of a corrector electrostatic prism 500 is shown, which may be described as Figure 3 The corrector electrostatic prism 312 and / or Figure 4 An example of a corrector electrostatic prism 416. Figure 5 In the example of FIG. 5 , the corrector electrostatic prism 500 is generally shaped around a central axis 501 (which may be represented by Figure 3 A solid shape rotated about a central axis 301).

[0200] like Figure 5 As shown, the corrector electrostatic prism 500 may include a corrector prism body 510 having a first corrector prism electrode 512 and a second corrector prism electrode 514 positioned radially outside the first corrector prism electrode 512. In this manner, the first corrector prism electrode 512 may also be referred to as an inner corrector prism electrode 512, and / or the second corrector prism electrode 514 may also be referred to as an outer corrector prism electrode 514.

[0201] like Figure 5As shown, the first corrector prism electrode 512 and the second corrector prism electrode 514 can be spaced apart to define an electrode gap 516 therebetween such that a deflector optical axis 508 along which the charged particle beam 502 travels extends within and / or through the electrode gap 516 . Figure 5 The deflector optical axis 508 shown may include and / or may be Figure 3 at least a portion of the deflector optical axis 308, and / or Figure 5 The charged particle beam 502 may include and / or may be Figure 3 at least a portion of the charged particle beam 302 .

[0202] The corrector electrostatic prism 500 can be configured such that when a first electrode voltage is applied to the first corrector prism electrode 512 and a second electrode voltage is applied to the second corrector prism electrode 514, the corrector electrostatic prism 500 generates an electrostatic deflection field that directs the charged particle beam 502 to travel along the deflector optical axis 508 through the corrector electrostatic prism 500. As described in more detail herein, applying the first electrode voltage and the second electrode voltage to the corrector electrostatic prism 500 can also be used to generate one or more auxiliary multipole fields (e.g., auxiliary quadrupole fields, auxiliary hexapole fields, auxiliary octopole fields, etc.), such as due to the geometry of the first corrector prism electrode 512 and / or the second corrector prism electrode 514.

[0203] Figure 3 Each of the incident electrostatic prism 304 and / or the exit electrostatic prism 306 may also have a configuration similar to Figure 5 The structure of the corrector electrostatic prism 500. For example, Figure 6 An example of an incident electrostatic prism 604 is shown, which can be described as Figure 3 An example of an incident electrostatic prism 304. In some examples, Figure 6 The structure shown may additionally or alternatively act as an exit electrostatic prism, such as Figure 3 The exit electrostatic prism 306. Figure 6 As shown, the incident electrostatic prism 604 may include an incident prism body 610 having a first incident prism electrode 612 and a second incident prism electrode 614 positioned radially outside the first incident prism electrode 612. In this manner, the first incident prism electrode 612 may also be referred to as an inner incident prism electrode 612, and / or the second incident prism electrode 614 may also be referred to as an outer incident prism electrode 614.

[0204] like Figure 6As shown, the first incident prism electrode 612 and the second incident prism electrode 614 can be spaced apart to define an electrode gap 616 therebetween, such that the deflector optical axis 608 along which the charged particle beam 602 travels extends within and / or through the electrode gap 616. Figure 6 The deflector optical axis 608 shown may include and / or may be Figure 3 at least a portion of the deflector optical axis 308, and / or Figure 6 The charged particle beam 602 may include and / or may be Figure 3 at least a portion of the charged particle beam 302 .

[0205] The corrector electrostatic prism 600 can be configured such that when a first electrode voltage is applied to the first incident prism electrode 612 and a second electrode voltage is applied to the second incident prism electrode 614, the corrector electrostatic prism 600 generates an electrostatic deflection field that guides the charged particle beam 602 to travel through the corrector electrostatic prism 600 along the deflector optical axis 608. In some examples, the same voltage can be applied to each of the first corrector prism electrode 512 of the corrector electrostatic prism 500 and the first incident prism electrode 612 of the incident electrostatic prism 604, and / or the same voltage can be applied to each of the second corrector prism electrode 514 of the corrector electrostatic prism 500 and the second incident prism electrode 614 of the incident electrostatic prism 604. Such a configuration can enable the corresponding deflector assembly to be regulated by guiding the charged particle beam along the deflector optical axis with fewer independent voltages, thereby facilitating stable control of such a system.

[0206] Figure 7 is a cross-sectional view of the corrector electrostatic prism 700, which can be represented Figure 3 Corrector electrostatic prism 312, Figure 4 The corrector electrostatic prism 416 and / or Figure 5 The corrector electrostatic prism 500. Specifically, Figure 7 A cross-sectional view showing a cross section separated from any electrostatic multipole element of the corrector electrostatic prism 700, such as along Figure 3 The corrector electrostatic prism 700 includes a corrector prism body 710 having a first corrector prism electrode 712 and a second corrector prism electrode 714 spaced apart from the first corrector prism electrode 712 to define an electrode gap 716 therebetween.

[0207] The corrector prism body 710, the first corrector prism electrode 712, the second corrector prism electrode 714 and the electrode gap 716 may be represented and / or referred to as Figure 5 The corrector prism body 510, the first corrector prism electrode 512, the second corrector prism electrode 514 and the electrode gap 516.

[0208] exist Figure 7 , the first electrode voltage applied to the first corrector prism electrode 712 is represented as V p1 , and the second electrode voltage applied to the second corrector prism electrode 714 is represented by V p2 .

[0209] As shown in the figure, Figure 7 The cross-sectional view can be described as being viewed along a direction parallel to the deflector optical axis 708 within the electrode gap 716. Figure 7 The deflector optical axis 708 shown may include and / or be located at Figure 5 The deflector optical axis 508 and / or Figure 3 The deflector optical axis 308. In addition, Figure 7 Can be described as viewing along a plane that does not intersect any multipole element of the deflector assembly.

[0210] like Figure 7 As shown, the first corrector prism electrode 712 may include a first electrode outer surface 720 facing the second corrector prism electrode 712 and a second electrode inner surface 730 facing the first corrector prism electrode 714. Figure 7 In the example of , each of the first electrode outer surface 720 and the second electrode inner surface 730 is a smooth surface (at least at a location away from the multipole elements included in the corrector electrostatic prism 800).

[0211] In some examples, the shape of the first electrode outer surface 720 and / or the second electrode inner surface 730 may correspond to the equipotential lines of the multipolar electrostatic field within the electrode gap 716. Specifically, in an electrostatic prism that is sufficiently far from the inlet and outlet fringe fields, such as the corrector electrostatic prism 700, the Laplace equation φ(x,y) of the electrostatic potential may be written as

[0212]

[0213] The corresponding multipolar extension (up to a sextupole potential) is given by

[0214] φ(x,y)=a0+a1x+a2(x 2 -y 2 )+b2(x 2 +y 2 )+a3(x 3 -3xy 2 )+b3x(x 2 +y 2 )+…(37)

[0215] in K=1 / R 棱镜, and it follows that φ(x,-y)=φ(x,y). In the limit K→0 or R 棱镜 →∞, all coefficients b m disappears, and φ(x,y) in equation (37) simplifies to the well-known multipole expansion around the direct axis. The expansion of equation (37) (where the coefficient a k and b k Depends on z = φR 棱镜 ) can be found in formula 3.55 in “Geometrical Charged-Particle Optics” (Harald H. Rose, 2009).

[0216] For electron energy eU, the axial dipole field

[0217] E x (0,0)=-a1=2KU=2U / R 棱镜 (38)

[0218] Ensure that the radius of curvature of electrons traveling along the deflector optical axis 708 is equal to R 棱镜 , and for the special case of a spherical prism, for the quadrupole field, And for the hexapole field, a3 = For a general prism, the dimensionless sextupole parameter p can be defined by the following formula:

[0219] a3=pK 3 U. (39)

[0220] In general, for any reasonable set of multipole intensities a1, a2, a3, a4, ..., we can convert Figure 7 The outlines of the first electrode outer surface 720 and the second electrode inner surface 730 are defined as the equipotential lines of equation (37); that is, φ(x, y) = V p1 And φ(x,y)=V p2 Ratio V p1 / V p2 can be close to -1, and these voltages can be selected so that φ(0,0) (i.e., the electrostatic potential at the deflector optical axis 808) is zero, or approximately zero. In practice, the beam diameter of the charged particle beam can be larger than the radial extent of the electrode gap 816 (i.e., Figure 7 2R in the example of ) is much smaller, so that for m ≥ 4 or 5, the multipole component a m Therefore, for given values ​​of a1, a2, and a3, many shapes of the first electrode outer surface 720 and the second electrode inner surface 730 are possible.

[0221] The first-order focusing characteristics of the corrector electrostatic prism 700 in the xz and yz planes can be determined by the quadrupole field parameter a2 of formula (37). Specifically, the first-order ray formula in the electrostatic prism can be written as

[0222]

[0223] This is for electrons with a nominal energy eU.

[0224] In some examples, such as Figure 7 In the example of , the electrostatic deflection field generated in the corrector electrostatic prism can be constant over the prism angle. Figure 7 can be described as illustrating a portion of a corrector electrostatic prism 700 viewed at a particular prism angle φ (as described above with reference to Figure 3 ), which may represent any one of a plurality of prism angles and / or any prism angle within a continuous range of prism angles.

[0225] In some examples, the shapes of the first electrode outer surface 720 and the second electrode inner surface 730 (e.g., the shapes of the corresponding profiles of these surfaces at a given prism angle φ) can be substantially constant within the corrector electrostatic prism 700 across a range of prism angles, such as across substantially the full angular range of the corrector electrostatic prism 700 and / or at locations remote from electrostatic multipole elements within the corrector electrostatic prism 700. Thus, in some examples, the magnitude of the electrostatic deflection field and / or its prismatic sextupole field component within the electrode gap 716 can be constant across the prism angle φ. In other words, in some examples, the coefficient a in equation (37) k and b k is independent of the prism angle, at least away from the prism exit and entrance and neglecting the field contribution from any electrostatic multipole elements associated with the corrector electrostatic prism. In some examples, for a range from zero to φ max This is the case for prism angles within substantially the entire prism angle range and / or prism angles that do not correspond to positions of electrostatic multipole elements.

[0226] Figure 8 is a cross-sectional view of another example of a corrector electrostatic prism 800, which can represent Figure 3 Corrector electrostatic prism 312, Figure 4 The corrector electrostatic prism 416 and / or Figure 5 The corrector electrostatic prism 500. Specifically, Figure 8 A cross-sectional view showing a cross section separated from any electrostatic multipole element of the corrector electrostatic prism 800, such as along Figure 3The corrector electrostatic prism 800 includes a corrector prism body 810 having a first corrector prism electrode 812 and a second corrector prism electrode 814 spaced apart from the first corrector prism electrode 812 to define an electrode gap 816 therebetween.

[0227] The corrector prism body 810, the first corrector prism electrode 812, the second corrector prism electrode 814 and the electrode gap 816 may be represented and / or referred to as Figure 5 The corrector prism body 510, the first corrector prism electrode 512, the second corrector prism electrode 514 and the electrode gap 516.

[0228] exist Figure 8 , the first electrode voltage applied to the first corrector prism electrode 812 is represented as V p1 , and the second electrode voltage applied to the second corrector prism electrode 814 is represented by V p2 .

[0229] As shown in the figure, Figure 8 The cross-sectional view can be described as being viewed along a direction parallel to the deflector optical axis 808 within the electrode gap 816. Figure 8 The deflector optical axis 808 shown may include and / or be located at Figure 5 The deflector optical axis 508 and / or Figure 3 The deflector optical axis 308. In addition, Figure 8 Can be described as viewing along a plane that does not intersect any multipole element of the deflector assembly.

[0230] Similar to Figure 7 Corrector electrostatic prism 700, Figure 8 The first corrector prism electrode 812 includes a first electrode outer surface 820 facing the second corrector prism electrode 812, and the second corrector prism electrode 814 includes a second electrode inner surface 830 facing the first corrector prism electrode 814. However, in this example, the first electrode outer surface 820 defines a first electrode groove 822 extending in a direction parallel to the deflector optical axis 808. Similarly, the second electrode inner surface 830 defines a second electrode groove 832 extending in a direction parallel to the deflector optical axis 808.

[0231] In some examples, the first electrode recess 822 and / or the second electrode recess 832 are sized, shaped, and / or otherwise configured to generate a desired auxiliary electrostatic field within the electrode gap 816. For example, the first electrode recess 822 and / or the second electrode recess 832 can generate a hexapole field within the corrector electrostatic prism 800 when corresponding voltages are applied to the first corrector prism electrode 812 and the second corrector prism electrode 814.

[0232] In some examples, the hexapole field generated by the first electrode groove 822 and / or the second electrode groove 832 varies along the deflector optical axis 808. The auxiliary hexapole field can be linearly proportional to the first electrode voltage and the second electrode voltage, which in turn can be related to the energy of the charged particles deflected by the first corrector prism electrode 812 and the second corrector prism electrode 814; thus, for a given charged particle energy, the hexapole fields induced by these grooves can be fixed.

[0233] Each of the first electrode recess 822 and the second electrode recess 832 may have any suitable dimensions, such as may correspond to a desired electrostatic field within the electrode gap 816. Figure 8 As shown, the corrector electrostatic prism can be formed by, for example, a central axis of the first corrector prism electrode 812 (e.g., Figure 3 The central axis 301 and / or Figure 5 The corrector prism beam radius R is measured between the central axis 501 of the deflector and the optical axis 808 of the deflector. 棱镜 The first electrode groove 822 can be characterized by a first electrode groove depth d1 as measured along a radial direction parallel to the corrector prism beam radius. Similarly, the second electrode groove 832 can be characterized by a second electrode groove depth d2 as measured along the radial direction. In some examples, each of the first electrode groove depth d1 and the second electrode groove depth d2 can be a radius of the corrector prism beam R 棱镜 At most 1 / 50.

[0234] In some examples, one or more dimensions of the first electrode groove 822 and / or the second electrode groove 832 (e.g., the first electrode groove depth d1 and / or the second electrode groove depth d2) may vary with the prism angle of the corrector electrostatic prism 800 (e.g., Figure 3 In such examples, the auxiliary prism multipole field also varies with the prism angle. Specifically, referring to formula (37), making one or more dimensions of the first electrode groove 822 and / or the second electrode groove 832 vary with the prism angle can result in a coefficient a k and b k Also varies with the prism angle. In some examples, the first electrode groove 822 and / or the second electrode groove 832 may be configured so that the axial potential (corresponding to a0) and the dipole field (corresponding to a1) remain constant or approximately constant with the prism angle when the prism hexapole field (corresponding to a3) follows the desired profile. In some examples, the first electrode groove 822 and / or the second electrode groove 832 may be configured so that the auxiliary octapole field (corresponding to a4) also varies with the prism angle.

[0235] Additionally or alternatively, one or more dimensions of the first electrode groove 822 and / or the second electrode groove 832 (e.g., first electrode groove depth d1 and / or second electrode groove depth d2) may be constant across the angular range (e.g., the full angular range) of the corrector electrostatic prism 800.

[0236] As mentioned above Figure 3 As discussed in the context of , one or more electrostatic multipole elements may be positioned and / or incorporated into a corrector electrostatic prism. As an example, Fig. 9 is a cross-sectional view of a corrector electrostatic prism 900 in which an electrostatic multipole element 950 is positioned. Specifically, Fig. 9 A view showing a cross-sectional surface intersecting the electrostatic multipole element 950, such as along Figure 3 View of line BB in .

[0237] The corrector electrostatic prism 900 may represent Figure 3 Corrector electrostatic prism 312, Figure 4 Corrector electrostatic prism 416, Figure 5 Corrector electrostatic prism 500, Figure 7 The corrector electrostatic prism 700 and / or Figure 8 The corrector electrostatic prism 800 of the embodiment of the present invention. The corrector electrostatic prism 900 includes a corrector prism body 910 having a first corrector prism electrode 912 and a second corrector prism electrode 914 spaced apart to define an electrode gap 916 therebetween. The corrector prism body 910, the first corrector prism electrode 912, the second corrector prism electrode 914, and the electrode gap 916 may represent and / or may be Figures 5 to 8 The corresponding structure shown in any one of the above. Fig. 9 , the first electrode voltage applied to the first corrector prism electrode 912 is represented as V p1 , and the second electrode voltage applied to the second corrector prism electrode 914 is represented by V p2 .

[0238] As shown in the figure, Fig. 9 The cross-sectional view can be described as being viewed along a direction parallel to the deflector optical axis 908 within the electrode gap 916. Fig. 9 The deflector optical axis 908 shown may include and / or be located at Figures 3 to 8 The deflector optical axis of any one of them.

[0239] The first corrector prism electrode 912 may include a first electrode outer surface 920 facing the second corrector prism electrode 914, and the first electrode outer surface 920 may define a first electrode recess 922 extending partially along a direction parallel to the deflector optical axis 908. Similarly, the second corrector prism electrode 914 may include a second electrode inner surface 930 facing the first corrector prism electrode 912, and the second electrode inner surface 930 may define a second electrode recess 932 extending partially along a direction parallel to the deflector optical axis 908.

[0240] exist Fig. 9 In the example of FIG. 1 , the electrostatic multipole element 950 is an electrostatic hexapole generating element, which includes a first hexapole electrode 952, a second hexapole electrode 954, a third hexapole electrode 956, a fourth hexapole electrode 958, a fifth hexapole electrode 960, and a sixth hexapole electrode 962. Therefore, applying a corresponding voltage to each of the hexapole electrodes of the electrostatic multipole element 950 is operable to generate dipole and quadrupole electrostatic fields of any orientation in the xy plane and / or in a manner similar to Figure 2 The six-pole generating element 200 of the embodiment of the present invention generates a six-pole field of fixed orientation. However, not all examples require such a configuration, and in addition, within the scope of the present disclosure, the electrostatic multipole element configured to generate a six-pole field may include more than six electrodes. Specifically, in some examples, configuring a six-pole generating element with more than six electrodes can enable the generation of multiple multipole fields, such as a rotatable six-pole field.

[0241] like Fig. 9 As shown, the first hexapole electrode 952, the second hexapole electrode 954 and the third hexapole electrode 956 can be at least partially received within the second corrector prism electrode 914 (e.g., within the second electrode recess 932), and the fourth hexapole electrode 958, the fifth hexapole electrode 960 and the sixth hexapole electrode 962 can be at least partially received within the first corrector prism electrode 912 (e.g., within the first electrode recess 922).

[0242] In some examples, the electrodes of the electrostatic multipole element positioned within the corrector electrostatic prism may be configured such that the inner surface defining the electrode gap within the corrector electrostatic prism remains substantially smooth. Fig. 9In the example of , the first hexapole electrode 952, the second hexapole electrode 954, and the third hexapole electrode 956 are positioned to be flush with and / or smoothly connected to the second electrode inner surface 930 outside the second electrode recess 932 to jointly define a smoothly changing profile. Similarly, in this example, the fourth hexapole electrode 958, the fifth hexapole electrode 960, and the sixth hexapole electrode 962 are positioned to be flush with and / or smoothly connected to the first electrode outer surface 920 outside the first electrode recess 922 to jointly define a smoothly changing profile. Therefore, the axial potential (a0 in Formula 37) and the dipole field (a1 in Formula 37) remain (almost) constant within the prism.

[0243] In this manner, the contour formed by the first electrode outer surface 920, the second electrode inner surface 930, and the hexapole electrodes of the electrostatic multipole element 950 may be substantially similar in shape to Figure 8 The contours shown and / or may correspond to the equipotential lines of equation (37) as discussed above. Additionally or alternatively, in some such examples, the magnitude of the electrostatic deflection field and / or its prismatic hexapole field component within the electrode gap 916 may be given by having coefficients a k and b k (37) with the coefficients being independent of the prism angle φ, at least away from the prism exit and entrance and ignoring the field contribution from any electrostatic multipole element 950 associated with the corrector electrostatic prism 500. In some examples, for a range from zero to φ max This is the case for prism angles within substantially the entire prism angle range and / or prism angles that do not correspond to the position of electrostatic multipole element 950.

[0244] As mentioned above Figure 3 As discussed in the context of , one or more electrostatic multipole elements may be formed at least in part by a portion of a corrector electrostatic prism shaped to produce a desired auxiliary multipole field. As an example, Fig.10 is a cross-sectional view of a corrector electrostatic prism 1000 that at least partially defines an electrostatic multipole element 1050. Specifically, Fig.10 Indicates along Figure 3 A view taken along line CC in FIG. 1 , which represents the exit surface of the corrector electrostatic prism 1000 .

[0245] Corrector electrostatic prism 1000 can represent Figure 3 Corrector electrostatic prism 312, Figure 4 Corrector electrostatic prism 416, Figure 5 Corrector electrostatic prism 500, Figure 7 Corrector electrostatic prism 700, Figure 8 The corrector electrostatic prism 800 and / or Fig. 9The corrector electrostatic prism 900 of the present invention. The corrector electrostatic prism 1000 includes a corrector prism body 1010 having a first corrector prism electrode 1012 and a second corrector prism electrode 1014 spaced apart to define an electrode gap 1016 therebetween. The corrector prism body 1010, the first corrector prism electrode 1012, the second corrector prism electrode 1014, and the electrode gap 1016 may represent and / or may be Figures 5 to 9 The corresponding structure shown in any one of the above. Fig.10 , the first electrode voltage applied to the first corrector prism electrode 1012 is represented by V p1 , and the second electrode voltage applied to the second corrector prism electrode 1014 is represented by V p2 .

[0246] As shown in the figure, Fig.10 The cross-sectional view can be described as being viewed along a direction parallel to the deflector optical axis 1008 within the electrode gap 1016. Fig.10 The deflector optical axis 1008 shown may include and / or be located at Figures 3 to 9 The deflector optical axis of any one of them.

[0247] exist Fig.10 In the example of , the first corrector prism electrode 1012 includes a first electrode protrusion 1070 extending toward the deflector optical axis 1008, and the second corrector prism electrode 1040 includes a second electrode recess 1072 recessed away from the deflector optical axis 1008. The first electrode protrusion 1070 and the second electrode recess 1072 can be configured (e.g., shaped and / or sized) such that when a first electrode voltage is applied to the first corrector prism electrode 1012 and a second electrode voltage is applied to the second corrector prism electrode 1014, the first electrode protrusion 1070 and the second electrode recess 1072 operate as an electrostatic multipole element 1050 to generate an auxiliary quadrupole field.

[0248] The first electrode bump 1070 and / or the second electrode recess 1072 may be located within the corrector electrostatic prism 1000, such as in an area adjacent to an entrance and / or exit of the corrector electrostatic prism. The first electrode bump 1070 and the second electrode recess 1072 may have any suitable dimensions, such as one or more other dimensions relative to the corrector electrostatic prism 1000. For example, referring to Fig.10With a gap radius R shown, the first electrode bump 1070 and / or the second electrode recess 1072 may have a depth 1073, as measured along a direction parallel to the deflector optical axis 1008, that is approximately equal to and / or less than R and / or less than 2R. Additionally or alternatively, the first electrode bump 1070 and / or the second electrode recess may have a width 1071, as measured along a direction perpendicular to the deflector optical axis 1008 and parallel to the central axis 1001, that is approximately equal to R and / or less than 3R.

[0249] Fig.11 Another example of an aberration correction system 1100 for at least partially correcting axial chromatic aberration of a charged particle beam 1102 is shown. The aberration correction system 1100 may be described as representing Figure 1 Similarly, the charged particle beam 1102 may include and / or may be Figure 1 A charged particle beam 104 is provided.

[0250] Fig.11 The aberration correction system 1100 is similar to Figure 3 Aberration correction system 300. For example, and as Fig.11 As shown, aberration correction system 1100 includes a deflector assembly 1110 that includes a corrector electrostatic prism 1112 and a plurality of electrostatic multipole elements 1114. Except as discussed below, all illustrated components of aberration correction system 1100, labeled or unlabeled, may share any suitable features, characteristics, properties, etc. with corresponding components of aberration correction system 300. Fig.11 For those components marked in FIG. 1, components marked with reference numerals of the form "11XX" are intended to be the same as those marked in FIG. Figure 3 Components marked with reference numerals of the form "3XX" correspond to the components marked with reference numerals of the form "3XX". For example, Fig.11 The incident electrostatic prism 1104 corresponds to Figure 3 The incident electrostatic prism 304 may be at least substantially identical to the incident electrostatic prism 304. In addition, the elementary rays of the charged particle beam 1102 passing through the aberration correction system 1100 may be substantially similar to Figure 4 Elementary rays 402, 404 and 406 are shown.

[0251] Similar to Figure 3 The aberration correction system 300, Fig.11 The aberration correction system 1100 includes a first sextupole generating element 1120, a second sextupole generating element 1122, a third sextupole generating element 1124, a first quadrupole generating element 1130 and a second quadrupole generating element 1132. The first sextupole generating element 1120, the second sextupole generating element 1122 and the third sextupole generating element 1124 can be connected to Figure 3The corresponding electrostatic multipole element 314 is configured and / or positioned in a substantially similar manner (e.g., relative to the corrector electrostatic prism 1112). Figure 3 Compared to the aberration correction system 300 of FIG. 1 , each of the first quadrupole generating element 1130 and the second quadrupole generating element 1132 is a tunable multipole element spaced apart from the corrector electrostatic prism 1112. Specifically, the first quadrupole generating element 1130 and the second quadrupole generating element 1132 can be positioned so that the respective quadrupole electrostatic fields generated by the first quadrupole generating element 1130 and the second quadrupole generating element 1132 overlap only minimally and / or negligibly with the deflection electrostatic field generated by the corrector electrostatic prism 1112.

[0252] In other examples, an aberration correction system (e.g., similar to Figure 3 Aberration correction system 300 or Fig.11 The aberration correction system 1100 may include a first quadrupole generating element and / or a second quadrupole generating element in the form of a tunable element at least partially received within the corrector electrostatic prism. For example, such an aberration correction system may include one or more quadrupole generating elements configured similar to Fig. 9 An electrostatic multipole element 950 of the embodiment of the present invention but having less than three (eg, one or two) electrodes coupled to each of the first prism electrode and the second prism electrode.

[0253] As discussed above with reference to equation (39), the dimensionless parameter p of the fixed hexapole field in the corrector electrostatic prism can be expressed via a3 = pK 3 U is defined. For a spherical prism, p=-5 / 4. For each of the incident and exit electrostatic prisms disclosed herein (e.g., for the incident electrostatic prism 304 and / or 1104 and / or for the exit electrostatic prism 306 and / or 1106), the hexapole parameter may be denoted as p1. For each of the corrector electrostatic prisms 300, 500, 700, 800, 900, and / or 1100, the hexapole parameter may be denoted as p2.

[0254] For a tunable sextupole field, it is convenient to use the sextupole excitation parameter h (in m -2 ) is defined as

[0255]

[0256] So that formula (24) becomes θ x =h(x 2 -y 2 ) and θ y =-2hxy. Reference Figure 3 and Fig.11For example, the hexapole excitation parameters corresponding to the first hexapole generating element 320 / 1120 (H1), the second hexapole generating element 322 / 1122 (H2), and the third hexapole generating element 334 / 1124 (H3) can be expressed as h1, h2, and h3, respectively. The aberration in the corrector exit focus (e.g., Figure 4 The corrector exit focus 410 shown) depends on the following parameters:

[0257]

[0258]

[0259] In this way, the hexapole excitations h1 and h2 enable chromatic aberration correction; that is, negative C cx =C cy can be set so that the axial chromatic aberration of the entire light column is eliminated. An advantageous choice of fixed hexapole parameters may be p1 = -1.084 and p2 = -2.012, in which case

[0260]

[0261] Although these formulas assume that the radius R 棱镜 It is not necessary for all examples for all three electrostatic prisms of the aberration correction system (e.g., the incident electrostatic prism 304 / 1104, the exit electrostatic prism 306 / 1106, and the corrector electrostatic prism 142 / 1112) to be identical. However, in some examples, it may be preferred that all such electrostatic prisms share a common value of the quantity R / R 棱镜 (where R represents Figures 7 to 9 ), which can greatly relax the corresponding voltage stability requirements for the voltage applied to each such prism. Specifically, in which each electrostatic prism is connected by R / R 棱镜 In the example characterized by the same value of , only two voltages (e.g., V and -V) need to be generated and applied appropriately to the respective prism electrodes in order to define the deflector optical axis.

[0262] Fig.12 Another example of an aberration correction system 1200 for at least partially correcting axial chromatic aberration of a charged particle beam 1202 is shown. The aberration correction system 1200 may be described as representing Figure 1 Similarly, the charged particle beam 1202 may include and / or may be Figure 1 A charged particle beam 104 is provided.

[0263] Fig.12 The aberration correction system 1200 is similar to Figure 3 The aberration correction system 300 and Fig.11Aberration correction system 1100. For example, and as Fig.12 As shown, aberration correction system 1200 includes a deflector assembly 1210 that includes a corrector electrostatic prism 1212 and a plurality of electrostatic multipole elements 1214. Except as discussed below, all illustrated components of aberration correction system 1200, labeled or unlabeled, may share any suitable features, characteristics, properties, etc. with corresponding components of aberration correction system 300 and / or aberration correction system 1100. Fig.12 For those components labeled in the Figure 3 Components marked with reference numerals of the form "3XX" and / or Fig.11 Components marked with reference numerals of the form "11XX" correspond to the components marked with reference numerals of the form "11XX". For example, Fig.12 The incident electrostatic prism 1204 corresponds to Figure 3 The incident electrostatic prism 304 and / or Fig.11 of the incident electrostatic prism 1104 and may be at least substantially identical thereto.

[0264] Fig.12 An example is shown in which the magnitude of the prismatic hexapole field within the corrector electrostatic prism 1212 varies with the prism angle φ. Specifically, in this example, the hexapole parameter p defined via equation (39) is a function of the prism angle.

[0265] exist Fig.12 In the example of FIG. 1 , the angular range of the corrector electrostatic prism 1200 can be divided into six sub-sectors: and Such sub-sectors can be associated with corresponding prism angle intervals, e.g.

[0266] and

[0267]

[0268] Where φ6=φ max And φ3=φ6 / 2.

[0269] exist Fig.12 In the example, there are six sub-sectors. and The sextupole parameters of can be expressed as p2, p3, p4, p4, p3 and p2 respectively; that is, the sextupole parameters maintain midplane symmetry. Figure 3 and Fig.11 As discussed, the sextupole parameter p1 may correspond to each of the incident electrostatic prism 1204 and the exit electrostatic prism 1206 .

[0270] The hexapole parameters may be chosen so that the corrector electrostatic prism 1212 contains no axial chromatic aberration with h1=h2=0:

[0271]

[0272] Alternatively, the additional degrees of freedom associated with the sub-sector hexapole parameters can be used to minimize geometric combined aberrations of order > 2, possibly violating midplane symmetry.

[0273] Fig.12 The example piecewise constant hexapole parameters of can be achieved in any of a variety of ways, such as by introducing corresponding changes in the profiles of the first prism electrode and the second prism electrode of the corrector electrostatic prism 1212. This can then be achieved, for example, by Figure 7 The method shown is achieved by introducing shallow grooves of corresponding shapes.

[0274] Although Fig.12 Examples are shown in which the hexapole parameters are piecewise constant with prism angle, but this is not required for all examples. For example, the corrector electrostatic prism may alternatively be configured so that the hexapole parameters vary smoothly, such as by smoothly varying the groove size with prism angle (e.g., Figure 8 The dimensions of the first electrode groove 822 and / or the second electrode groove 832 are selected in practice so that a0 and a1 of FIG. (37) are constant or almost constant over the prism angle, so that the electrostatic potential and the dipole field as measured on the deflector optical axis are correspondingly constant over the prism angle.

[0275] Fig.13 Another example of an aberration correction system 1300 for at least partially correcting axial chromatic aberration of a charged particle beam 1302 is shown. The aberration correction system 1300 may be described as representing Figure 1 Similarly, the charged particle beam 1302 may include and / or may be Figure 1 A charged particle beam 104 is provided.

[0276] Fig.13 The aberration correction system 1300 is similar to Figure 3 Aberration correction system 300, Fig.11 The aberration correction system 1100 and Fig.12 Aberration correction system 1200. For example, and as Fig.13As shown, aberration correction system 1300 includes a deflector assembly 1310 that includes a corrector electrostatic prism 1312 and a plurality of electrostatic multipole elements 1314. Except as discussed below, all illustrated components of aberration correction system 1300, labeled or unlabeled, may share any suitable features, characteristics, properties, etc. with corresponding components of aberration correction system 300, aberration correction system 1100, and / or aberration correction system 1200. Fig.13 For those parts marked in FIG. 13, parts marked with reference numerals of the form "13XX" are intended to be the same as those marked in FIG. Figure 3 Components marked with reference numerals of the form "3XX", Fig.11 Components marked with reference numerals of the form "11XX" and / or Fig.12 Components marked with reference numerals of the form "12XX" correspond to the components marked with reference numerals of the form "12XX". For example, Fig.13 The incident electrostatic prism 1304 corresponds to Figure 3 The incident electrostatic prism 304, Fig.11 The incident electrostatic prism 1104 and / or Fig.12 of the incident electrostatic prism 1204 and may be at least substantially identical thereto.

[0277] Similar to the previously discussed examples, the plurality of electrostatic multipole elements 1314 of the aberration correction system 1300 includes a first hexapole generating element 1320, a second hexapole generating element 1322, and a third hexapole generating element 1324. Fig.13 In the example of , the plurality of electrostatic multipole elements also includes a fourth sextupole generating element 1326 configured to generate a fourth sextupole field (e.g., as the main or only multipole field). Specifically, in this example, at least four sextupole generating elements may be required to fully correct axial chromatic aberration while not generating second-order aberrations.

[0278] like Fig.13 As shown, the second hexapole generating element 1322 and the third hexapole generating element 1324 are positioned within the corrector electrostatic prism 1312, while the first hexapole generating element 1320 and the fourth hexapole generating element 1326 are positioned outside and spaced apart from the corrector electrostatic prism 1312. However, in other examples, the first hexapole generating element 1320 and the fourth hexapole generating element 1326 may be positioned within the corrector electrostatic prism 1312.

[0279] Similar to the examples discussed previously, and as Fig.13 As shown, the plurality of electrostatic multipole elements 1314 further include a first quadrupole generating element 1330 and a second quadrupole generating element 1332. Fig.13In the example of , each of the first quadrupole generating element 1330 and the second quadrupole generating element 1332 is configured to generate a corresponding auxiliary quadrupole field (e.g., as a main or only multipolar field). Specifically, in this example, similar to Fig.12 The first quadrupole generating element 1230 and / or the second quadrupole generating element 1232 are integrated into the exit electrostatic prism 1306 and / or are at least partially defined by the exit electrostatic prism. Fig.12 The first quadrupole generating element 1230 and / or the second quadrupole generating element 1232 are integrated into and / or at least partially defined by the incident electrostatic prism 1304. In such examples, the first quadrupole generating element 1330 and / or the second quadrupole generating element 1332 may correspond to portions of the respective electrostatic prisms that are shaped to generate the corresponding auxiliary quadrupole fields.

[0280] However, this is not required, and further within the scope of the present disclosure, the first quadrupole generating element 1330 and / or the second quadrupole generating element 1332 may include a corresponding plurality of poles for generating a corresponding (non-auxiliary) quadrupole field. In such examples, each of the first quadrupole generating element 1330 and / or the second quadrupole generating element 1332 may be positioned within or spaced apart from the exit electrostatic prism 1306 and the entrance electrostatic prism 1304, respectively.

[0281] Fig.14 Elementary rays x of a charged particle beam 1400 are shown, respectively labeled 1402, 1404, and 1406. a (z), y a (z) and x κ (z), the charged particle beam passes through an aberration correction system such as Fig.13 aberration correction system 1300. In other words, Fig.14 The charged particle beam 1400 may include Fig.13 charged particle beam 1302 and / or at least a portion thereof. Fig.14 shows the direction corresponding to Fig.13 The deflector optical axis 1308 and / or the collimated optical axis 1418 of the z-axis are provided. Fig.14 As shown, a charged particle source (e.g., Figure 1 The charged particle source 102) is imaged onto the corrector inlet 1408, and the corrector exit focus 1410 is imaged onto the sample plane via appropriate optics. S A sample or specimen (e.g. Figure 1 On sample 132). Fig.14 In the example of FIG. 1 , such optical devices include a transfer lens 1440 and an objective lens 1442, which can be similar to Figure 1 transfer lens 122 and / or objective lens 128.

[0282] Fig.14 Also shown are the positions of the first quadrupole generating element 1452, the second quadrupole generating element 1472, the first hexapole generating element 1462, the second hexapole generating element 1464, the third hexapole generating element 1466 and the fourth hexapole generating element 1468 relative to the collimated optical axis 1418 and relative to the basic light rays 1402, 1404 and 1406. Fig.14 The first quadrupole generating element 1452 and the second quadrupole generating element 1472 correspond to Fig.13 The first quadrupole generating element 1330 and the second quadrupole generating element 1332. The first hexapole generating element 1462, the second hexapole generating element 1464, the third hexapole generating element 1466 and the fourth hexapole generating element 1468 correspond to Fig.13 The first hexapole generating element 1320 , the second hexapole generating element 1322 , the third hexapole generating element 1324 and the fourth hexapole generating element 1326 . Fig.14 Also shown are the positions of the incident electrostatic prism 1450, the exit electrostatic prism 1470, and the corrector electrostatic prism 1460, which correspond to Fig.13 The incident electrostatic prism 1304, the exit electrostatic prism 1306 and the corrector electrostatic prism 1312.

[0283] like Fig.14 As shown, the charged particle beam 1400 (and thus Fig.13 The charged particle beam 1302) exhibits a point focus at the mid-plane position 1340 / 1430 of the deflector optical axis 1308 / 1418 within the corrector electrostatic prism 1312. Therefore, and as Fig.13 As shown, the energy selection slit 1342 can be positioned at the intermediate surface position 1340 to monochromatize the charged particle beam 1302. Fig.13 Aberration correction system 1300 can be used as a Cc corrector and / or a monochromator. Other aberration correction systems disclosed herein that produce line focus at the intermediate plane position can also be used as a monochromator; however, the point focus produced by aberration correction system 1300 can make the system particularly advantageous for use in this manner.

[0284] like Fig.14 Additionally shown, the charged particle beam 1400 (and thus Fig.13 The charged particle beam 1302 of the deflector optics 1308 exhibits a line focus at locations on either side of the intermediate surface location 1430. In some examples, each of the second hexapole generating element 1322 and the third hexapole generating element 1324 can be positioned at or adjacent to a location along the deflector optical axis 1308 corresponding to such a line focus location.

[0285] In the above examples, the aberration correction system 300 / 1000 / 1100 / 1200 / 1300 is configured such that the corresponding deflector optical axis 308 / 1008 / 1108 / 1208 / 1308 passing through the deflector assembly 310 / 1110 / 1210 / 1310 is α-shaped. However, this is not required, and further within the scope of the present disclosure, the deflector optical axis may pass through the deflector assembly via an Ω-shaped (i.e., shaped in a manner similar to the Greek letter Ω) path. This can be achieved, for example, by using multiple (e.g., four) 90-degree electrostatic prisms to guide the deflector optical axis through a generally Ω-shaped path, although other configurations (e.g., electrostatic prism deflection angles) may also be used. In the present disclosure, any example of an aberration correction system and / or its deflector assembly characterized by a generally Ω-shaped deflector optical axis may be referred to as an "Ω-type" system or assembly.

[0286] Fig.15 1 shows aspects of another example of an aberration correction system 1500 that includes four 90 degree electrostatic prisms 1522, 1524, 1526, and 1528 configured to direct a charged particle beam 1502 along a deflector optical axis 1508 that follows a generally Ω-shaped path. The aberration correction system 1500 may be described as representing Figure 1 Similarly, the charged particle beam 1502 may include and / or may be Figure 1 A charged particle beam 104 is provided.

[0287] like Fig.15 As shown, the aberration correction system 1500 includes a deflector assembly 1520 having a first electrostatic prism 1522, a second electrostatic prism 1524, a third electrostatic prism 1526 and a fourth electrostatic prism 1528.

[0288] The first electrostatic prism 1522, the second electrostatic prism 1524, the third electrostatic prism 1526, and the fourth electrostatic prism 1528 may be arranged and / or coupled to each other in any suitable configuration. For example, at least the second electrostatic prism 1524 and the third electrostatic prism 1526 may be fixedly coupled to each other and / or may represent corresponding components and / or portions of a single integral device. Additionally or alternatively, at least the first electrostatic prism 1522 and the fourth electrostatic prism 1528 may be fixedly coupled to each other and / or may represent corresponding components and / or portions of a single integral device.

[0289] exist Fig.15In the example of the first electrostatic prism 1522, the second electrostatic prism 1524, the third electrostatic prism 1526, and the fourth electrostatic prism 1528, each of which is configured to deflect the charged particle beam 1510 through an angle equal to or approximately equal to 90 degrees. However, this is not required, and further within the scope of the present disclosure, each electrostatic prism of the deflection assembly 1520 can deflect the charged particle beam 1510 through any suitable angle. In some examples, one or more of the first electrostatic prism 1522, the second electrostatic prism 1524, the third electrostatic prism 1526, and / or the fourth electrostatic prism 1528 is a dual focusing prism.

[0290] Each electrostatic prism of the deflector assembly 1520 can also be characterized by a corresponding multipole strength and / or quadrupole parameter. Specifically, referring to formula (37), each of the first electrostatic prism 1522 and the fourth electrostatic prism 1528 can be characterized by a quadrupole strength a2=K 2 U, and each of the second electrostatic prism 1524 and the third electrostatic prism 1526 can be characterized by a quadrupole intensity In this way, each of the second electrostatic prism 1524 and the third electrostatic prism 1526 can have the same form of quadrupole strength as in the spherical deflector (but with a different hexapole strength a3 than the spherical deflector).

[0291] like Fig.15 As shown, the deflector assembly 1520 also includes a plurality of electrostatic multipole elements 1530. Specifically, Fig.15 In the example, the plurality of electrostatic multipole elements 1530 include a first multipole element 1538 configured to generate a first hexapole field, a second multipole element 1540 configured to generate a second hexapole field, and a third multipole element 1542 configured to generate a third hexapole field.

[0292] In some examples, the deflector assembly 1520 may also include one or more multipole elements configured to generate a quadrupole field. Fig.15 As shown, the plurality of electrostatic multipole elements may also include a fourth multipole element 1536 configured to generate a fourth element quadrupole field, a fifth multipole element 1544 configured to generate a fifth element quadrupole field, a sixth multipole element 1532 configured to generate a sixth element quadrupole field, a seventh multipole element 1534 configured to generate a seventh element quadrupole field, an eighth multipole element 1546 configured to generate an eighth element quadrupole field, and a ninth multipole element 1548 configured to generate a ninth element quadrupole field.

[0293] Additionally, in this example, first multipole element 1538 may also be configured to generate a first element quadrupole field, and third multipole element 1542 may also be configured to generate a third element quadrupole field. In this manner, each of first multipole element 1538 and third multipole element 1542 may be described as representing each of a hexapole generating element and a quadrupole generating element.

[0294] The first element hexapole field and the first element quadrupole field generated by the first multipole element 1538 may at least partially overlap (e.g., in space and / or along the deflector optical axis 1508). For example, the first hexapole field and the first element quadrupole field may correspond to and / or may be respective components of the electrostatic multipole field generated by the first multipole element 1538.

[0295] The first multipole element 1538 may have any suitable structure for generating the first hexapole field and the first element quadrupole field. For example, the first multipole element 1538 may include and / or may be a hexapole generating element configured to generate each of the first hexapole field and the first element quadrupole field when a suitable voltage is applied to the six electrodes of the hexapole generating element. Additionally or alternatively, the first multipole element 1538 may include a quadrupole generating element having four electrodes and each of different hexapole generating elements having six electrodes, which are respectively configured to generate the first hexapole field and the first element quadrupole field.

[0296] Similarly, the third hexapole field and the third element quadrupole field generated by the third multipole element 1542 can at least partially overlap (e.g., in space and / or along the deflector optical axis 1508). For example, the third hexapole field and the third element quadrupole field can correspond to and / or can be respective components of the electrostatic multipole field generated by the third multipole element 1542.

[0297] The third multipole element 1542 may have any suitable structure for generating the third hexapole field and the third element quadrupole field. For example, the third multipole element 1542 may include and / or may be a hexapole generating element configured to generate each of the third hexapole field and the third element quadrupole field when a suitable voltage is applied to the six electrodes of the hexapole generating element. Additionally or alternatively, the third multipole element 1542 may include a quadrupole generating element having four electrodes and each of different hexapole generating elements having six electrodes, which are respectively configured to generate the third hexapole field and the third element quadrupole field.

[0298] Similar to the example discussed above, Fig.15 Each electrostatic multipole element 1530 shown in dashed lines in FIG. 1 represents an electrostatic multipole element configured to generate a corresponding auxiliary multipole field having one or more characteristics fixed by the multipole geometry, while Fig.15Each electrostatic multipole element shown in solid lines in represents an electrostatic multipole element configured to generate a corresponding multipole field that can be independently tuned (e.g., in orientation and / or magnitude). Fig.15 In the example, each of sixth multipole element 1532, seventh multipole element 1534, eighth multipole element 1546, and ninth multipole element 1548 is configured to generate an auxiliary multipole field, while all other electrostatic multipole elements 1530 are configured to generate a tunable multipole field.

[0299] In some examples, first electrostatic prism 1522 may include and / or define at least a portion of each of sixth multipole element 1532 and seventh multipole element 1534. For example, the entrance and / or exit of first electrostatic prism 1522 may be shaped and / or otherwise configured to generate a sixth element quadrupole field and / or a seventh element quadrupole field, respectively, when a deflection voltage is applied to first electrostatic prism 1522. In other examples, sixth multipole element 1532 and / or seventh multipole element 1534 may be fixedly coupled to first electrostatic prism 1522.

[0300] Similarly, in some examples, fourth electrostatic prism 1528 may include and / or define at least a portion of each of eighth multipole element 1546 and ninth multipole element 1548. For example, the entrance and / or exit of fourth electrostatic prism 1528 may be shaped and / or otherwise configured to generate an eighth element quadrupole field and / or a ninth element quadrupole field, respectively, when a deflection voltage is applied to fourth electrostatic prism 1528. In other examples, eighth multipole element 1546 and / or ninth multipole element 1548 may be fixedly coupled to fourth electrostatic prism 1528.

[0301] exist Fig.15 In the example of , a plurality of electrostatic multipole elements 1530 are arranged in a mirror-symmetric configuration about a mid-plane position 1504 of a deflector optical axis 1508 within a deflector assembly 1520. For example, and as Fig.15 As shown, second multipole element 1540 may be positioned adjacent mid-plane location 1504 , and fourth multipole element 1536 , first multipole element 1538 , third multipole element 1542 , and fifth multipole element 1544 may be arranged in a mirror-symmetric configuration with respect to second multipole element 1540 .

[0302] Similar to Figure 4 and Fig.14 , Fig.16 Elementary rays x, respectively labeled 1612, 1614, and 1616, of a charged particle beam 1610 passing through an aberration correction system 1600 are shown. a (z), y a (z) and x κ (z). Fig.16The aberration correction system 1600 may be represented by Fig.15 An example of an aberration correction system 1500. For example, Fig.16 The charged particle beam 1610 may include Fig.15 Charged particle beam 1502 and / or at least a portion thereof. Fig.16 In the figures, the deflector optical axis 1602 is straightened for clarity, but it should be understood that the deflector optical axis 1602 can be at least partially curved.

[0303] Fig.16 Also shown are various structural components of the aberration correction system 1600 in representative positions along the deflector optical axis 1602. Fig.16 As shown, the aberration correction system 1600 includes a deflector assembly 1620 having a first electrostatic prism 1622, a second electrostatic prism 1624, a third electrostatic prism 1626, and a fourth electrostatic prism 1628. The first electrostatic prism 1622, the second electrostatic prism 1624, the third electrostatic prism 1626, and the fourth electrostatic prism 1628 may respectively represent and / or correspond to Fig.15 The first electrostatic prism 1522, the second electrostatic prism 1524, the third electrostatic prism 1526 and the fourth electrostatic prism 1528. Similarly, Fig.16 A plurality of multipole elements 1630 are shown, including a first multipole element 1638, a second multipole element 1640, a third multipole element 1642, a fourth multipole element 1636, a fifth multipole element 1644, a sixth multipole element 1632, a seventh multipole element 1634, an eighth multipole element 1646, and a ninth multipole element 1648, which may respectively represent and / or correspond to Fig.15 1540 , a third multipole element 1542 , a fourth multipole element 1536 , a fifth multipole element 1544 , a sixth multipole element 1532 , a seventh multipole element 1534 , an eighth multipole element 1546 , and a ninth multipole element 1548 .

[0304] exist Fig.16 , various multipole elements are shown as two solid overlapping rectangles to represent the multiple multipole fields that can be generated by such multipole elements. For example, the two solid overlapping rectangles associated with each of the first multipole element 1638 and the third multipole element 1642 can be understood to represent the corresponding hexapole field and quadrupole field generated by each element.

[0305] like Fig.16 As shown, the deflector assembly 1620 operates to produce a line focus of the charged particle beam 1610 at the intermediate surface position 1604, so that the second multipole element 1640 is positioned adjacent to a position along the deflector optical axis 1602 corresponding to the line focus position.

[0306] like Fig.16 As further shown, the deflector assembly 1620 may also include one or more circular lens elements 1660 and an objective lens element 1662. Each circular lens element 1660 may include and / or may be any suitable electrostatic circular lens. In some examples, the circular lens element 1660 may correspond to and / or may be Figure 1 The condenser optics 108 and / or transfer lens 122. Similarly, Fig.16 The objective lens element 1662 shown may correspond to and / or may be Figure 1 Objective lens 128.

[0307] Fig.17 1700, which includes four 90-degree electrostatic prisms to direct a charged particle beam 1710 along a deflector optical axis 1702 that follows a generally Ω-shaped path. Figure 4 , Fig.14 and Fig.16 , Fig.17 Elementary rays x, labeled 1712, 1714, and 1716, respectively, of a charged particle beam 1710 passing through an aberration correction system 1700 are shown. a (z), y a (z) and x κ (z). Fig.17 In the figures, the deflector optical axis 1702 is straightened for clarity, but it should be understood that the deflector optical axis 1702 can be at least partially curved.

[0308] Fig.17 The aberration correction system 1700 may be represented by Fig.15 Another example of an aberration correction system 1500. For example, Fig.17 The charged particle beam 1710 may include Fig.15 charged particle beam 1502 and / or at least a portion thereof.

[0309] Fig.17 The aberration correction system 1700 is similar to Fig.16 Aberration correction system 1600. For example, and as Fig.17 As shown, the aberration correction system 1700 includes a deflector assembly 1720, which includes four 90-degree electrostatic prisms and a plurality of electrostatic multipole elements 1730. Unless otherwise specified, all illustrated components of the aberration correction system 1700, whether labeled or not, may be the same as those shown in FIG. Fig.15 The aberration correction system 1500 and / or Fig.16 The corresponding components of the aberration correction system 1600 share any suitable features, characteristics, properties, etc. Fig.17For those parts marked in FIG. 17, parts marked with reference numerals of the form "17XX" are intended to be the same as those parts marked in FIG. Fig.15 Reference numerals of the form "15XX" and / or Fig.16 For example, the first electrostatic prism 1722 corresponds to Fig.15 The first electrostatic prism 1522 and / or Fig.16 The first electrostatic prism 1622 may be at least substantially identical thereto.

[0310] and Fig.16 Compared to deflector assembly 1620 of FIG. 1 , fourth multipole element 1636 of deflector assembly 1720 is additionally configured to generate a fourth hexapole field (in addition to the fourth element quadrupole field), and fifth multipole element 1744 is additionally configured to generate a fifth hexapole field (in addition to the fifth element quadrupole field). Thus, in this example, the fourth hexapole field at least partially overlaps the fourth element quadrupole field, and the fifth hexapole field at least partially overlaps the fifth element quadrupole field.

[0311] Similar to the first multipole element 1638 and the third multipole element 1742, each of the fourth multipole element 1636 and the fifth multipole element 1744 can be configured to generate corresponding quadrupole fields and hexapole fields in any suitable manner, such as with a single multipole (e.g., hexapole) element or with a combination of hexapole generating elements and quadrupole generating elements.

[0312] Relative to Fig.16 The aberration correction system 1600 comprises Fig.17 The two additional sextupole fields (i.e., the fourth sextupole field and the fifth sextupole field) of the aberration correction system 1700 can reduce off-axis aberrations, thereby making the aberration correction system 1600 less sensitive to beam drift.

[0313] Fig.18 Another example of a charged particle microscope system 1800 that may include and / or utilize an aberration correction system as disclosed herein is shown. Specifically, and as described in more detail below, the charged particle microscope system 1800 may include a plurality of quadrupole and octopole electrostatic elements that collectively operate to substantially reduce or eliminate spherical aberration C of a charged particle beam. S This configuration can produce large source demagnification in a relatively short optical column, which can be particularly beneficial for FIB systems and / or plasma FIB systems corrected for chromatic and / or spherical aberrations, because the focused probe is less blurred by Coulomb interactions in shorter columns.

[0314] Fig.18 The charged particle microscope system 1800 is similar to Figure 1For example, the charged particle microscope system 1800 includes a charged particle source 1802 that emits a charged particle beam 1804 along an emission axis 1806 and toward a focusing column 1810 (which may also be referred to herein as an optical column 1810). The charged particle beam 1804 travels through the focusing column 1810 along an optical axis 1818. The optical axis 1818 may include and / or may be a curved optical axis, such as any of the deflector optical axes 308 / 518 / 618 / 708 / 808 / 908 / 1008 / 1108 / 1208 / 1308 / 1418 / 1602 / 1702 disclosed herein. Fig.18 As shown, the charged particle microscope system 1800 may include a condenser optical device 1808 that accelerates / decelerates, focuses, and / or directs the charged particle beam 1804 toward a focusing column 1810.

[0315] Downstream of the focusing column 1810, the charged particle microscope system 1800 includes a sample holder 1860 that holds a sample 1862 and a detector 1868 that is configured to detect charged particles 1864 emitted from the sample 1862 as a result of the charged particle beam 1804 being incident on the sample 1862. The charged particle microscope system 1800 may also include one or more computing devices 1870 that are programmed and / or configured to control the operation of one or more aspects of the charged particle microscope system 1800.

[0316] Except as discussed below, all illustrated components of charged particle microscope system 1800, labeled or unlabeled, may be used in conjunction with Figure 1 The corresponding components of the charged particle microscope system 100 share any suitable features, characteristics, properties, etc. In addition, the charged particle microscope system 1800 may include the charged particle microscope system 1800 described herein. Figure 1 Charged particle microscope system 100 discloses any suitable components and / or exhibits any suitable functionality.

[0317] exist Fig.18 In the example of FIG. 1 , the light column 1810 can be configured to at least partially correct the axial spherical aberration and / or the axial chromatic aberration of the charged particle beam 1804. Fig.18 As shown, light column 1810 includes a multipole condenser 1820 and a multipole objective 1840 located downstream of multipole condenser 1820. Multipole condenser 1820 includes one or more condenser quadrupole generating elements 1822, and multipole objective 1840 includes a plurality of objective multipole elements 1842. In some examples, one or more beam limiting apertures may be positioned upstream of multipole condenser 1820.

[0318] The plurality of objective multipole elements 1842 may have any of a variety of configurations, examples of which are discussed in more detail below. In general, the plurality of objective multipole elements 1842 include at least three quadrupole generating elements and at least three octopole generating elements that are configured to at least partially correct for spherical aberration of the charged particle beam 1804. In some examples, and as described in more detail below, one or more objective multipole elements 1842 are operable to generate a quadrupole field as well as an octopole field, and thus may be described as representing both a quadrupole generating element and an octopole generating element.

[0319] In some examples, and as Fig.18 As shown, the light column also includes a chromatic aberration corrector 1830 positioned between the multipole condenser 1820 and the multipole objective 1840. In such examples, the chromatic aberration corrector 1830 may include and / or may be any suitable device for at least partially correcting the axial chromatic aberration of the charged particle beam 1804. Examples of the chromatic aberration corrector 1830 include any of the aberration correction systems 300, 1100, 1200, 1300, 1600, and / or 1700, and / or any suitable portions and / or components thereof. In other examples, the chromatic aberration in the charged particle beam 1804 can be at least partially corrected by the emitter corrector.

[0320] Similar to Figure 1 100, the charged particle microscope system 1800 may include and / or may be one or more different types of EM and / or charged particle microscopes, examples of which include scanning electron microscopes (SEMs), scanning transmission electron microscopes (STEMs), transmission electron microscopes (TEMs), charged particle microscopes (CPMs), dual beam microscope systems, etc. Thus, the charged particle source 1802 may be configured to emit a charged particle beam 1804 having any suitable accelerating voltage, such as an accelerating voltage corresponding to the type of microscopy being performed. As an example, the charged particle source 1802 can be configured to emit a charged particle beam 1804 having an acceleration voltage of at least 200 volts (V), at least 1,000 V, at least 5,000 V, at least 10,000 V, at least 20,000 V, at least 50,000 V, at most 100,000 V, at most 30,000 V, at most 15,000 V, at most 7,000 V, at most 2,000 V and / or at most 500 V.

[0321] Fig.19 Aspects of another example of a charged particle microscope system 1900 are shown, which may be described as representing Fig.18 Example of a charged particle microscope system 1800. Fig.19The charged particle microscope system 1900 includes a charged particle source 1902 that emits a charged particle beam 1904 and an optical column 1910 that directs the charged particle beam 1904 toward a sample 1960. The charged particle beam 1904 travels through the optical column 1910 along an optical axis 1918. Fig.19 Also shown are elementary rays x(z), y(z), and x(z), labeled 1912, 1914, and 1916, respectively, of the charged particle beam 1904 as it passes through the light column 1910. κ (z) example.

[0322] Unless otherwise indicated, all illustrated components of the charged particle microscope system 1900, labeled or unlabeled, may be used in conjunction with Fig.18 The corresponding components of the charged particle microscope system 1800 share any suitable features, characteristics, properties, etc. Fig.19 For those parts marked in the Fig.18 Components marked with reference numerals of the form "18XX" correspond to the components marked with reference numerals of the form "18XX". For example, Fig.19 The concentrator optics 1908 corresponds to Fig.18 The concentrator optical device 1808 may be at least substantially the same as the concentrator optical device 1808.

[0323] like Fig.19 As shown, the charged particle microscope system 1900 includes a chromatic aberration corrector 1930, which can be described as Fig.18 An example of a chromatic aberration corrector 1830. Fig.19 As shown, the chromatic aberration corrector 1930 includes an incident electrostatic prism 1932, a corrector electrostatic prism 1934 and an exit electrostatic prism 1936, as well as a plurality of electrostatic quadrupole generating elements labeled Q1, ..., Q4 and a plurality of electrostatic hexapole generating elements labeled H1, ..., H3.

[0324] The chromatic aberration corrector 1930 may be similar to Figure 3 The aberration correction system 300 and / or Fig.11 The aberration correction system 1100 of the present invention can be described in detail. For example, the incident electrostatic prism 1932 and the exit electrostatic prism 1936 can share any suitable features, characteristics, attributes, etc. with the incident electrostatic prism 304 / 1104 and / or the incident electrostatic prism 306 / 1106, respectively. Similarly, the corrector electrostatic prism 1934 can share any suitable features, characteristics, attributes, etc. with the corrector electrostatic prism 312 / 1112.

[0325] like Fig.19As shown, the charged particle microscope system 1900 includes a multipole condenser 1920, which includes a quadrupole doublet 1922. Specifically, the quadrupole doublet 1922 includes a first condenser quadrupole generating element 1924 and a second condenser quadrupole generating element 1926 positioned downstream of the first condenser quadrupole generating element 1924. The first condenser quadrupole generating element 1924 is configured to generate a first condenser quadrupole field, and the second condenser quadrupole generating element 1926 is configured to generate a second condenser quadrupole field. In other examples, the multipole condenser 1920 may include a single quadrupole generating element.

[0326] In addition, Fig.19 In the example of , the charged particle microscope system 1900 includes a multipole objective 1940 having a plurality of objective multipole elements 1942. Specifically, in Fig.19 In the example of , the plurality of objective multipole elements 1942 include a first objective multipole element 1944, a second objective multipole element 1946 positioned downstream of the first objective multipole element 1944, and a third objective multipole element 1948 positioned downstream of the second objective multipole element 1946. The first objective multipole element 1944, the second objective multipole element 1946, and the third objective multipole element 1948 are configured to generate a first objective multipole field, a second objective multipole field, and a third objective multipole field, respectively.

[0327] Each electrostatic multipole element of charged particle microscope system 1800 and / or charged particle microscope system 1900 can have any suitable configuration for generating a corresponding multipole field. As an example, Fig. 20 An example of a multipole element 2000 comprising a first electrode 2010, a second electrode 2020, a third electrode 2030 and a fourth electrode 2040 is shown, each electrode being configured to receive a corresponding voltage to generate a corresponding component of a corresponding multipole field. Therefore, the multipole element 2000 may be referred to as a quadrupole generating element 2000 and / or may be configured to generate a quadrupole field. In other words, the multipole element 2000 may be configured such that the multipole field generated by the multipole element 2000 includes a quadrupole field as a main component of the multipole field.

[0328] However, in some examples, multipole element 2000 may also be configured so that the multipole field generated by multipole element 2000 also includes additional multipole field components, such as an octopole field component. Specifically, each of first electrode 2010, second electrode 2020, third electrode 2030, and fourth electrode 2040 may be configured (e.g., shaped) so that the total multipole field generated by multipole element 2000 includes a quadrupole field component and an octopole field component. In some examples, the relative magnitude and / or corresponding configuration of the quadrupole field and the octopole field generated by multipole element 2000 may be controlled via applying appropriate corresponding voltages to the electrodes of multipole element 2000 and / or via appropriate shaping of the electrodes of multipole element 2000.

[0329] like Fig. 20 As shown, multipole element 2000 may be characterized by multipole element inner diameter 2002, which represents the minimum separation distance between opposing electrodes, as measured along a line perpendicular to Fig. 20 The multipole element inner diameter 2002 may additionally or alternatively be described as representing the maximum diameter of a charged particle beam passing through the multipole element 2000. The multipole element inner diameter 2002 may take any one of a number of values, such as a value within the range of approximately 1-5 millimeters (mm).

[0330] Fig.21 Another example of a multipole element 2100 is shown, which can represent any suitable multipole element of the charged particle microscope system 1800 and / or the charged particle microscope system 1900. Fig.21 In the example of FIG. 2 , the multipolar element 2100 includes a first electrode pair 2110, a second electrode pair 2120, a third electrode pair 2130, and a fourth electrode pair 2140. The first electrode pair 2110 includes a first electrode 2112 and a second electrode 2114; the second electrode pair 2120 includes a third electrode 2122 and a fourth electrode 2124; the third electrode pair 2130 includes a fifth electrode 2132 and a sixth electrode 2134; and the fourth electrode pair 2140 includes a seventh electrode 2142 and an eighth electrode 2144.

[0331] In some examples, Fig.21 The multipole element 2100 can be configured to generate a quadrupole field as a primary multipole field. For example, the multipole element 2100 can be configured so that each of the first electrode pair 2110, the second electrode pair 2120, the third electrode pair 2130, and the fourth electrode pair 2140 can receive a corresponding voltage for generating a corresponding quadrupole field. Therefore, in such examples, the multipole element 2100 can be described as representing a quadrupole generating element.

[0332] Additionally or alternatively, the multipole element 2100 can be configured so that each of the first electrode 2112, the second electrode 2114, the third electrode 2122, the fourth electrode 2124, the fifth electrode 2132, the sixth electrode 2134, the seventh electrode 2142, and the eighth electrode 2144 can receive a corresponding voltage for generating a corresponding multipole field. In such examples, the multipole element 2100 can be configured to operate as a quadrupole generating element for aberration correction as described herein, and to generate a small deflection field superimposed on the quadrupole field to scan a charged particle beam relative to a sample. Specifically, the multipole element 2100 is configured so that different deflection voltages can be applied to each electrode in each electrode pair to facilitate the generation of such deflection fields while minimizing the generation of undesirable multipole fields (e.g., sextupole fields) that may introduce additional aberrations.

[0333] In some examples, multipole element 2100 can additionally or alternatively be configured to produce an octopole field (e.g., as the primary or sole multipole field). In some examples, the relative magnitudes and / or respective configurations of the octopole and quadrupole fields produced by multipole element 2100 can be controlled via application of appropriate respective voltages to electrodes of multipole element 2100 and / or via appropriate shaping of the electrodes of multipole element 2100.

[0334] like Fig.21 As shown, multipole element 2000 may be characterized by multipole element inner diameter 2102, which represents the minimum separation distance between opposing electrodes, as measured along a line perpendicular to Fig.21 The multipole element inner diameter 2102 may additionally or alternatively be described as representing the maximum diameter of a charged particle beam passing through the multipole element 2100. The multipole element inner diameter 2102 may take any one of a number of values, such as a value within the range of approximately 1-5 mm.

[0335] Figure 22 to Figure 25 Aspects of additional examples of charged particle microscope systems are shown, which are labeled 2200, 2300, 2400, and 2500, respectively. Each of charged particle microscope system 2200, charged particle microscope system 2300, charged particle microscope system 2400, and charged particle microscope system 2500 may be described as representing Fig.18 Example of a charged particle microscope system 1800.

[0336] Fig. 22 The Charged Particle Microscope System 2200 and Fig.23 The charged particle microscope system 2300 may be described as representing similar charged particle microscope systems or the same charged particle microscope system under different operating conditions (ie, at different magnifications of the charged particle beam).

[0337] therefore, Fig.23 All illustrated components of the charged particle microscope system 2300, labeled or unlabeled, may be used with Fig. 22 The corresponding components of the charged particle microscope system 2200 share any suitable features, characteristics, properties, etc. Fig.23 For those parts marked in FIG. 23, parts marked with reference numerals of the form "23XX" are intended to be the same as those marked in FIG. Fig. 22 The parts marked with reference numerals of the form "22XX" correspond to the parts marked with reference numerals of the form "22XX".

[0338] Additionally, unless otherwise indicated, all illustrated components, labeled or unlabeled, of the charged particle microscope system 2200 or 2300 may be used in conjunction with any of the following: Fig.18 The corresponding components of the charged particle microscope system 1800 share any suitable features, characteristics, properties, etc. Figure 22 to Figure 23 For those parts marked in the Fig.18 The parts marked with reference numerals of the form "18XX" correspond to the parts marked with reference numerals of the form "18XX".

[0339] Although not in Figure 22 to Figure 25 Although not specifically shown in any of the charged particle microscope systems 2200 / 2300 / 2400 / 2500, it should be understood that any of the charged particle microscope systems 2200 / 2300 / 2400 / 2500 may include and / or be used in combination with any of the chromatic aberration correction systems disclosed herein and / or any suitable components thereof. For example, any of the aberration correction systems 300 / 1100 / 1200 / 1300 / 1500 / 1600 / 1700 / 1800 and / or any suitable portion thereof may be similar to Fig.18 The chromatic aberration corrector 1830 is positioned along the optical axis 2218 / 2318 / 2418 / 2518.

[0340] Similarly, Fig.24 The Charged Particle Microscope System 2400 and Fig.25 The charged particle microscope system 2500 may be described as representing similar charged particle microscope systems or the same charged particle microscope system under different operating conditions (ie, at different magnifications of the charged particle beam).

[0341] therefore, Fig.25 All illustrated components of the charged particle microscope system 2500, labeled or unlabeled, may be used with Fig.24 The corresponding components of the charged particle microscope system 2400 share any suitable features, characteristics, properties, etc. Fig.25 For those components marked in FIG. 25, components marked with reference numerals of the form "25XX" are intended to be the same as those marked in FIG. Fig.24 Components marked with reference numerals of the form "24XX" correspond to the components in the accompanying drawings.

[0342] Additionally, unless otherwise indicated, all illustrated components, labeled or unlabeled, of the charged particle microscope system 2400 or 2500 may be used in conjunction with any of the following: Fig.18 The corresponding components of the charged particle microscope system 1800 share any suitable features, characteristics, properties, etc. Figure 24 to Figure 25 For those parts marked in the Fig.18 The parts marked with reference numerals of the form "18XX" correspond to the parts marked with reference numerals of the form "18XX".

[0343] refer to Fig. 22 , a charged particle microscope system 2200 includes a charged particle source 2202 that emits a charged particle beam 2204 and an optical column 2210 that directs the charged particle beam 2204 toward a sample 2260. The charged particle beam 2204 travels through the optical column 2210 along an optical axis 2218. Fig. 22 Also shown are examples of elementary rays x(z) and y(z), labeled 2212 and 2214, respectively, of the charged particle beam 2204 as it passes through the light column 2210. Fig. 22 In the example of , the charged particle microscope system 2200 also includes a plurality of beam deflectors 2252 positioned along the optical axis 2218. Such beam deflectors 2252 can be used to deflect the charged particle beam 2204 to scan the charged particle beam 2204 across the sample 2260.

[0344] like Fig. 22 shown, and similar to Fig.19 The charged particle microscope system 1900, the charged particle microscope system 2200 includes a multipole condenser 2220 having a quadrupole doublet lens 2222, the quadrupole doublet lens including a first condenser quadrupole generating element 2224 and a second condenser quadrupole generating element 2226. Fig. 22 In the example of, each of the first concentrator quadrupole generating element 2224 and the second concentrator quadrupole generating element 2226 is configured to generate a respective quadrupole field. In other examples, the multipolar concentrator 2220 may include a single quadrupole generating element, such as the first concentrator quadrupole generating element 2224.

[0345] Further similar to Fig.19 The charged particle microscope system 1900 of the invention further comprises a multipole objective lens 2240 having a plurality of objective lens multipole elements 2242. The plurality of objective lens multipole elements 2242 comprise a first objective lens multipole element 2244, a second objective lens multipole element 2246 positioned downstream of the first objective lens multipole element 2244, and a third objective lens multipole element 2248 positioned downstream of the second objective lens multipole element 2246.

[0346] The first objective multipole element 2244, the second objective multipole element 2246 and the third objective multipole element 2248 are configured to generate a first objective multipole field, a second objective multipole field and a third objective multipole field, respectively. Fig. 22 In the example of , the first objective multipole field includes a first objective quadrupole field component and a first objective field octopole field component. The second objective multipole field includes a second objective quadrupole field component and a second objective octopole field component. The third objective multipole field includes a third objective quadrupole field component and a third objective octopole field component. In this way, the plurality of objective multipole elements 2242 can be described as including exactly three quadrupole generating elements. In other words, in this example, exactly three objective multipole elements 2242 are configured to generate quadrupole field components.

[0347] Each of the objective multipole elements 2242 may have any suitable form and / or configuration for generating a corresponding objective multipole field. In some examples, each of the first objective multipole element 2244 and the second objective multipole element 2246 includes four electrodes that are shaped to generate an octopole field in addition to a quadrupole field. As an example, one or both of the first objective multipole element 2244 and the second objective multipole element 2246 may be similar to and / or may be Fig. 20 Multipole element 2000.

[0348] Additionally or alternatively, in some examples, the third objective multipole element 2248 may include eight electrodes for generating both a quadrupole field and an octopole field. As an example, the third objective multipole element 2248 may be similar to and / or may be Fig.21 This configuration may be particularly beneficial in examples where the third objective multipole element 2248 is used as a deflector for AC scanning of the charged particle beam 2204 (possibly in combination with the beam deflector 2252). In such examples, large and undesirable auxiliary hexapole fields may accompany the deflection field. Fig.21 Configuring the third objective multipole element 2248 to include eight different electrodes in the manner of the multipole element 2100 can enable eight corresponding deflection voltages to be applied to these electrodes in a mutually proportional configuration so that these undesirable six-pole fields are cancelled to deflect in the x and / or y direction. Alternatively, the third objective multipole element 2248 can be Fig. 20 The multipole element 2000 includes four electrodes, and an additional multipole element configured to perform AC scanning can be introduced downstream of the third objective multipole element 2248. In this example, the additional multipole element can include eight nominally identical electrodes for generating a corrective octopole field.

[0349] However, not all examples require this configuration. For example, it is also within the scope of the present disclosure that one or both of the first objective multipole element 2244 and the second objective multipole element 2246 can be Fig.21 Additionally or alternatively, the third objective lens multipole element 2248 may have four electrodes shaped as Fig. 20 The octopole field is generated by means of 2000 multipole elements.

[0350] As discussed above, Fig. 22 The Charged Particle Microscope System 2200 and Fig.23 The charged particle microscope system 2300 is at least substantially the same except for the magnification produced in the corresponding illustrated particle beam. Specifically, Fig. 22 An example with a magnification of 0.02 is shown, while Fig.23 An example with a magnification of 0.2 is shown. In each case, with reference to the elementary rays x(z) 2212 / 2312 and y(z) 2214 / 2314, it can be seen that the charged particle beam 2204 / 2304 lacks an intermediate point crossing (where x(z) = y(z) = 0) between the multipole condenser 2220 / 2320 and the multipole objective 2240 / 2340. Therefore, this configuration can significantly reduce the undesirable Coulomb interactions between charged particles that may occur at such point crossings.

[0351] In addition, refer to Figure 22 to Figure 23 2212 / 2312 and y(z) 2214 / 2314, it can be seen that for a portion of the charged particle beam 2204 / 2304 extending through the multipole objective 2240 / 2340 (e.g., for the entire beam length within the multipole objective), |y(z)|≤|x(z)|. In addition, in each example, the charged particle beam 2204 / 2304 enters the multipole objective 2240 / 2340 with a non-circular beam profile (e.g., an elongated and / or elliptical beam profile) and maintains the non-circular beam profile through at least a portion of the multipole objective 2240 / 2340.

[0352] exist Fig. 22 In the example of FIG. 2 , the multipole condenser 2220 and the multipole objective 2240 are configured so that the axial spherical aberration of the charged particle beam 2204 at the sample 2260 is eliminated. In this example, the lateral component of the axial chromatic aberration of the charged particle beam 2204 is C cx =41mm and C cy =7.5mm. Similarly, Fig.23In the example of FIG. 2 , the multipole condenser 2320 and the multipole objective 2340 are configured so that the axial spherical aberration of the charged particle beam 2304 at the sample 2360 is eliminated. In this example, the lateral component of the axial chromatic aberration of the charged particle beam 2304 is C cx =41mm and C cy =9mm. Therefore, Figure 22 to Figure 23 In the example of FIG. 2 , axial chromatic aberration is nearly eliminated in the yz plane at multiple magnifications of the charged particle beam 2204 / 2304 .

[0353] Fig.24 The charged particle microscope system 2400 is basically similar to Figure 22 to Figure 23 Charged Particle Microscope System 2200 / 2300. However, Figure 22 to Figure 23 Unlike the example of , the charged particle microscope system 2400 includes a multipole objective 2440, which includes four objective multipole elements 23442. Specifically, in Fig.24 In the example, the multipole objective 2440 includes a first objective multipole element 2444, a second objective multipole element 2446 positioned downstream of the first objective multipole element 2444, a third objective multipole element 2448 positioned downstream of the second objective multipole element 2446, and a fourth objective multipole element 2450 positioned downstream of the third objective multipole element 2448.

[0354] The first objective multipole element 2444, the second objective multipole element 2446, the third objective multipole element 2448 and the fourth objective multipole element 2450 are configured to generate a first objective multipole field, a second objective multipole field, a third objective multipole field and a fourth objective multipole field, respectively. Fig.24 In the example of , the first objective multipole field includes a first objective quadrupole field component and a first objective field octopole field component. The second objective multipole field includes a second objective octopole field component. The third objective multipole field includes a third objective quadrupole field component and a third objective octopole field component. The fourth objective multipole field includes a fourth objective quadrupole field component. In this way, the plurality of objective multipole elements 23442 can be described as including exactly three quadrupole generating elements. In other words, in this example, exactly three objective multipole elements 23442 are configured to generate quadrupole field components.

[0355] Each objective multipole element 2442 may have any suitable form and / or configuration for generating a corresponding objective multipole field. In some examples, each of the first objective multipole element 2444 and the third objective multipole element 2448 includes four electrodes that are shaped to generate an octopole field in addition to a quadrupole field. As an example, one or both of the first objective multipole element 2444 and the third objective multipole element 2448 may be similar to and / or may be Fig. 20 Multipole element 2000.

[0356] Additionally or alternatively, in some examples, the second objective multipole element 2446 may include eight electrodes for generating an octopole field. As an example, the second objective multipole element 2446 may be similar to and / or may be Fig.28 The multipole element 2800 will be described in more detail below.

[0357] Additionally or alternatively, in some examples, fourth objective multipole element 2450 may include eight electrodes for generating both a quadrupole field and an octopole field. As an example, fourth objective multipole element 2450 may be similar to and / or may be Fig.21 Multipole element 2100.

[0358] However, not all examples require this configuration. For example, it is also within the scope of the present disclosure that one or more of the first objective multipole element 2444, the second objective multipole element 2446, and / or the third objective multipole element 2448 may be Fig.21 Additionally or alternatively, the fourth objective lens multipole element 2450 may have four electrodes shaped as Fig. 20 The octopole field is generated by means of 2000 multipole elements.

[0359] As discussed above, Fig.24 The Charged Particle Microscope System 2400 and Fig.25 The charged particle microscope system 2500 is at least substantially the same except for the magnification produced in the corresponding illustrated particle beam. Specifically, Fig.24 An example with a magnification of 0.02 is shown, while Fig.25 An example with a magnification of 0.1 is shown. In each case, with reference to the elementary rays x(z) 2412 / 2512 and y(z) 2414 / 2514, it can be seen that the charged particle beam 2404 / 2504 lacks an intermediate point crossing (where x(z) = y(z) = 0) between the multipole condenser 2420 / 2520 and the multipole objective 2440 / 2540. Therefore, this configuration can significantly reduce the undesirable Coulomb interactions between charged particles that may occur at such point crossings.

[0360] In addition, refer to Figure 24 to Figure 252412 / 2512 and y(z) 2414 / 2514, it can be seen that for a portion of the charged particle beam 2404 / 2504 extending through the multipole objective 2440 / 2540 (e.g., for the entire beam length within the multipole objective), |y(z)|≤|x(z)|. In addition, in each example, the charged particle beam 2404 / 2504 enters the multipole objective 2440 / 2540 with a non-circular beam profile (e.g., an elongated and / or elliptical beam profile) and maintains the non-circular beam profile through at least a portion of the multipole objective 2440 / 2540.

[0361] exist Fig.24 In the example of FIG. 2 , the multipole condenser 2420 and the multipole objective 2440 are configured so that the axial spherical aberration of the charged particle beam 2404 at the sample 2460 is eliminated. In this example, the lateral component of the axial chromatic aberration of the charged particle beam 2404 is C cx =46mm and C cy =24mm. Similarly, Fig.25 In the example of FIG. 2 , the multipole condenser 2520 and the multipole objective 2540 are configured so that the axial spherical aberration of the charged particle beam 2504 at the sample 2560 is eliminated. In this example, the lateral component of the axial chromatic aberration of the charged particle beam 2504 is C cx =51mm and C cy =28mm. Therefore, Figure 24 to Figure 25 In the example of FIG. 2 , at multiple magnifications of the charged particle beam 2404 / 2504 , the axial chromatic aberration in the yz plane is significantly smaller than the axial chromatic aberration in the xz plane.

[0362] The apparatus and systems of the present disclosure may also be particularly applicable to examples where a charged particle microscope system directs multiple charged particle beams to a sample and / or a target focus position. As an example, Fig.26 A configuration is shown in which each of a first charged particle beam 2604 (e.g., a SEM beam) and a second charged particle beam 2614 (e.g., a FIB beam) are focused to a common location on a sample 2630. In this example, the first charged particle beam 2604 travels along a first axis 23602, while the second charged particle beam 2614 travels along a second axis 2612.

[0363] like Fig.26As shown, the first charged particle beam 2604 can be characterized by and / or associated with a first exclusion zone 2606, which is characterized by a first exclusion zone angular range 2608. For example, the first exclusion zone 2606 can represent a beam profile of the first charged particle beam 2604 approaching the sample 2630, or can represent an area associated with (e.g., occupied by) a lens component that directs the first charged particle beam 2604 to the sample 2630. Fig.26 In the example of FIG. 26 , the first exclusion zone 2606 is a conical region that terminates at the sample 2630 .

[0364] The first exclusion zone 2606 may represent an area that cannot be occupied by the second charged particle beam 2614 or associated lens components. Fig.26 As shown, the second charged particle beam 2614 can be directed toward the sample 2630 by and / or via a multipole objective lens 2620 including a first objective lens multipole element 2622, a second objective lens multipole element 2624, and a third objective lens multipole element 2626, each of which must be positioned outside the first exclusion zone 2606. The multipole objective lens 2620 can represent Figure 22 to Figure 23 The multipole objective 2240 / 2340, or any other multipole objective of similar configuration.

[0365] exist Fig.26 In the example of FIG. 26 , the first axis 2602 is orthogonal to the surface of the sample 2630, so that the first charged particle beam 2604 and the sample 2630 jointly confine the second charged particle beam 2614 and associated components to occupy a free space 2616 defined therebetween. The free space can be, for example, Fig.26 The free space angle 2618 measured in the xz plane is characterized.

[0366] In some examples, free space angle 2618 may represent a limit on how close multipole elements of multipole objective 2620 may be positioned relative to sample 2630. In general, it may be desirable to position the multipole elements of multipole objective 2620 as close to sample 2630 as possible in order to minimize chromatic aberrations as well as higher-order geometric aberrations, both intrinsic (i.e., excluding mechanical errors) and parasitic (i.e., aberrations due to mechanical errors). Therefore, and as described in more detail below, multipole objective 2620 may be configured such that multipole objective 2620 may be desirably positioned close to sample 2630 while maintaining components of multipole objective 2620 (e.g., multipole elements) individually within free space 172616 outside of first exclusion zone 2606.

[0367] Fig. 27 Shows something like Fig.21The objective lens multipole element 2700 of the multipole element 2100. Specifically, the objective lens multipole element 2700 includes a first electrode pair 2710, a second electrode pair 2720, a third electrode pair 2730, and a fourth electrode pair 2740. The first electrode pair 2710 includes a first electrode active surface 2712 and a first electrode extension 2716 extending away from the first electrode active surface 2712, and a second electrode active surface 2714 and a second electrode extension 2718 extending away from the second electrode active surface 2714. The second electrode pair 2720 includes a third electrode active surface 2722 and a third electrode extension 2726 extending away from the third electrode active surface 2722, and a fourth electrode active surface 2724 and a fourth electrode extension 2728 extending away from the fourth electrode active surface 2724. The third electrode pair 2730 includes a fifth electrode active surface 2732 and a fifth electrode extension 2736 extending away from the fifth electrode active surface 2732, and a sixth electrode active surface 2734 and a sixth electrode extension 2738 extending away from the sixth electrode active surface 2734. The fourth electrode pair 2740 includes a seventh electrode active surface 2742 and a seventh electrode extension 2746 extending away from the seventh electrode active surface 2742, and an eighth electrode active surface 2744 and an eighth electrode extension 2748 extending away from the eighth electrode active surface 2744.

[0368] exist Fig. 27 In the example of FIG. 1 , each of the first electrode active surface 2712, the second electrode active surface 2714, the third electrode active surface 2722, the fourth electrode active surface 2724, the fifth electrode active surface 2732, the sixth electrode active surface 2734, the seventh electrode active surface 2742, and the eighth electrode active surface 2744 faces the central hole 2701 of the multipole element 2700. The central hole 2701 can be characterized by the multipole element inner diameter 2702, which represents the minimum separation distance between the opposing electrodes, such as along a direction perpendicular to Fig. 27 In this manner, objective multipole element 2700 can be described as representing Fig.21 Multi-pole element 2100, Fig.26 Additionally or alternatively, Fig.21 The multi-pole element 2100 may be described as representing and / or showing Fig. 27 A portion of the objective lens multipole element 2700.

[0369] exist Fig. 27In the example of , each electrode of the objective lens multipole element 2700 is formed as a MEMS device. Specifically, in this example, each of the first electrode extension 2716, the second electrode extension 2718, the third electrode extension 2726 and the eighth electrode extension 2748 is supported by a first electrode support 2750, and each of the fourth electrode extension 2728, the fifth electrode extension 2736, the sixth electrode extension 2738 and the seventh electrode extension 2746 is supported by a second electrode support 2760.

[0370] Configuring the electrodes of objective multipole element 2700 to be formed as a MEMS device can facilitate forming objective multipole element 2700 so that multipole element inner diameter 2702 is significantly smaller than multipole element inner diameters in conventional electrode designs, thereby further facilitating positioning objective multipole element 2700 adjacent to a sample. Such a configuration can also facilitate producing objective multipole element 2700 with reduced mechanical errors and / or tighter dimensional tolerances relative to non-MEMS systems. It should be understood that any multipole element disclosed herein (including any multipole element containing more or less than eight electrodes) can also be formed as a MEMS device in the manner of objective multipole element 2700.

[0371] Objective multipole element 2700 may also be referred to by one or more of its linear dimensions (e.g., as in Fig. 27 For example, and as Fig. 27 As shown, the objective lens multipole element 2700 has a first dimension 2706 as measured along the x-direction, which is smaller than a second dimension 2704 as measured along the y-direction. As discussed in more detail below, this configuration can facilitate positioning such an objective lens multipole element 2700 at a position corresponding to Fig. 27 In the x-dimension of the space, the region is restricted.

[0372] Fig.28 Another example of a multipole element 2800 is shown, which may be used, for example, Fig.26 The multipole element 2800 includes a plurality of electrodes 2840 defining a central aperture 2830 therebetween. The central aperture 2830 is at least partially along a beam axis 2802 (such as Fig.26 of the second axis 2612 and / or charged particle beam (e.g., Fig.26 The charged particle beam 2614) may extend along another axis along which it travels. Specifically, Fig.28 A view of multipole element 2800 is shown with beam axis 2802 extending into the page. It should be understood that each electrode 2840 can have a thickness along a direction parallel to beam axis 2802 such that central aperture 2830 defined by electrodes 2840 can be described as extending along beam axis 2802.

[0373] Similar to Figure 2 The electrostatic hexapole generating element 200, the multipole element 2800 can be configured to generate an electrostatic multipole field by applying corresponding voltages to the electrodes 2840. Fig.28 In the example of, multipole element 2800 includes eight electrodes 2840 and can therefore be configured to generate an octapole electrostatic field. In such examples, multipole element 2800 can therefore be described as representing an octapole generating element. Additionally or alternatively, multipole element 2800 can be configured to generate any of a variety of other multipole fields, such as a quadrupole electrostatic field, a hexapolar electrostatic field, etc., via applying appropriate voltages to its eight electrodes 2840. Therefore, multipole element 2800 can be additionally or alternatively referred to as electrostatic multipole element 2800.

[0374] exist Fig.28 In the example of , each electrode 2840 includes a corresponding electrode active surface 2842 facing and / or partially defining the central hole 2830 and a corresponding electrode extension 2844 extending away from the electrode active surface 2842. Each electrode extension 2844 may include and / or define a corresponding electrical contact location 2846, which is configured to be electrically coupled to another component (e.g., an electrical lead) to supply a voltage to the electrode. In this manner, each electrode active surface 2842 can generate a corresponding electrostatic field component based on a voltage supplied to a corresponding electrical contact location 2846 spaced apart from the electrode active surface 2842.

[0375] exist Fig.28 In the example of FIG. 2 , each electrode extension 2844 (or at least a portion thereof) extends at least partially in a lateral direction away from the corresponding electrode active surface 2842. Specifically, the plurality of electrodes 2840 include electrodes generally positioned at Fig.28 The first side electrode subset 2852 on the left side is generally positioned at Fig.28 Second side electrode subset 2856 on the right side.

[0376] like Fig.28 As shown, for each electrode 2840 in the first side electrode subset 2852, the electrode extension 2844 extends away from the electrode active surface 2842 along a first lateral direction 2816 that is perpendicular to the beam axis 2802. Similarly, for each electrode 2840 in the second side electrode subset 2856, the electrode extension 2844 extends away from the electrode active surface 2842 along a second lateral direction 2818 that is perpendicular to the beam axis 2802 and opposite to the first lateral direction 2816.

[0377] like Fig.28As shown, electrode extensions 2844 of electrodes 2840 in first side electrode subset 2852 may be described as extending into and terminating in first side region 2850 of multipole element 2800. Similarly, electrode extensions 2844 of electrodes 2840 in second side electrode subset 2856 may be described as extending into and terminating in second side region 2854 of multipole element 2800. First side region 2850 and second side region 2854 may correspond to spaced-apart regions of multipole element 2800 positioned on opposite sides of central aperture 2830.

[0378] In some examples, first lateral direction 2816 and second lateral direction 2818 are coplanar and / or antiparallel to each other. Specifically, in such examples, electrode 2840 and / or its electrode extension 2844 can extend away from central hole 2830 in a common plane that is at least substantially perpendicular to beam axis 2802. However, this is not required in all examples, and it is also within the scope of the present disclosure that at least a portion of multipole element 2800 is non-planar. For example, in some examples, and as described below with reference to Fig.31 Discussed in more detail, each electrode extension 2844 can extend away from the electrode active surface 2842 in a direction that is angled relative to each of a radial direction perpendicular to the beam axis 2802 and an axial direction parallel to the beam axis 2802 .

[0379] In addition, Fig.28 , multipole element 2800 has different linear dimensions along a direction perpendicular to beam axis 2802. Specifically, in this example, electrode 2840 extends away from center hole 2830 such that multipole element 2800 has a first dimension 2806 as measured along a first direction 2804 perpendicular to beam axis 2802 that is smaller than a second dimension 2810 of multipole element 2800 as measured along a second direction 2808 perpendicular to each of beam axis 2802 and first direction 2804. This configuration can facilitate positioning of multipole element 2800 adjacent to a target focus position when the free area around a target focus position in which multipole element 2800 can be positioned is constrained in at least one dimension. For example, referring to Fig.26 , for a given position of a multipole element (e.g., third objective multipole element 2626) along second axis 2612, free space 2616 in which the multipole element is positioned can have a greater angular extent in the y direction than in the x direction, such that the multipole element can correspondingly have a greater extent in the y direction than in the x direction. Fig.28 The multi-pole element 2800 represents Fig.26 In the example of the third objective multipole element 2626, Fig.28 The first direction 2804 may represent Fig.26 The x direction, and Fig.28 The second direction 2808 may represent Fig.26 y direction.

[0380] First dimension 2806 and second dimension 2810 of multipole element 2800 can have any of a variety of relative ranges. As an example, the ratio of second dimension 2810 to first dimension 2806 can be at least 1.2:1, at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at most 4:1, at most 2.7:1, at most 2.3:1, at most 1.7:1 and / or at most 1.3:1.

[0381] Although Fig.28 Referring to an example in which the multi-pole element 2800 includes eight electrodes 2840, it should be understood that the present invention is not limited to the following examples. Fig.28 The configurations and features described may also be applied to multipolar elements including any other number of electrodes, such as four electrodes, six electrodes, 12 electrodes, 16 electrodes, etc. Similarly, references herein to Fig.28 The configurations and features described may also be applied to multipole elements configured to generate a quadrupole electrostatic field, a hexapole electrostatic field, an octupole electrostatic field, a 12-pole electrostatic field, etc.

[0382] Fig.29 Another example of a multipole element 2900 is shown, which may be used in space-constrained applications, such as for Fig.26 In a dual beam system. Similar to Fig.28 The multipole element 2800 of the embodiment of the present invention comprises a plurality of electrodes 2940 defining a central hole 2930 therebetween, each electrode comprising a corresponding electrode active surface 2942 and a corresponding electrode extension 2944.

[0383] In examples where it is desired to generate an electrostatic multipole field having a multipole multiplicity that is different from the number of electrodes of the multipole element, Fig.29 The configuration can be particularly beneficial. As discussed above, a multipole element with eight electrodes can be configured to generate a quadrupole electrostatic field by applying appropriate voltages to the eight electrodes. However, in some cases, due to the large coupling between the quadrupole field and the 12-pole field, this quadrupole field is accompanied by an undesirable parasitic 12-pole electrostatic field. Such parasitic fields can be described as artifacts of the electrode geometry. For example, when all electrodes (or their active surfaces) have the same shape, this coupling may be particularly strong.

[0384] In various examples, such parasitic fields can be minimized and / or eliminated by configuring the multipole element to include multiple electrodes corresponding to the desired multiplicity of the multipole field generated. For example, configuring the multipole element to include 12 electrodes can enable the multipole element to generate a quadrupole field with minimal parasitic 12-pole fields, and generate an octopole field with a parasitic 16-pole field of acceptable magnitude. However, in some examples, spatial constraints and / or other practical considerations exclude the use of 12-pole elements to generate quadrupole fields and / or octopole fields, such as due to the lack of space in which the required 12 different electrical connections are formed and / or included. However, configuring the multipole element to include eight electrodes of different shapes can enable the generation of both quadrupole and octopole electrostatic fields while limiting the accompanying parasitic fields to acceptable small magnitudes.

[0385] As an example, Fig.29 An example is shown in which the electrodes 2940 are configured so that their active surfaces 2942 are not all identical in shape. Specifically, in this example, the plurality of electrodes 2940 includes a first shape electrode subset 2960 (indicated by hatching) and a second shape electrode subset 2962 (indicated by stippling). The electrode active surface 2942 of each electrode 2940 in the first shape electrode subset 2960 has a first active surface shape, while the electrode active surface 2942 of each electrode 2940 in the second shape electrode subset 2962 has a second active surface shape that is different from the first active surface shape. As used herein, each of the first active surface shape and the second active surface shape refers to the shape of the corresponding electrode active surface 2942 when viewed along a direction parallel to the beam axis 2930 (e.g., as Fig.29 For example, refer to Fig.29 , the first active surface shape can be described as a circular shape with a relatively large radius of curvature, while the second active surface shape can be described as a circular shape with a relatively small radius of curvature. Additionally or alternatively, the first active surface shape can be described as wider than the second active surface shape.

[0386] exist Fig.29 In the example of the first shape electrode subset 2960 and the second shape electrode subset 2962, each includes an equal number of electrodes 2940 (i.e., four electrodes 2940). Additionally, in this example, the electrodes 2940 in the first shape electrode subset 2960 are circumferentially staggered with the electrodes 2940 in the second shape electrode subset 2962 in an alternating manner. Other configurations are also within the scope of the present disclosure.

[0387] Fig.29An example of a multipole element 2900 including eight electrodes 2940 and configured to generate a quadrupole electrostatic field within a central aperture 2930 may be represented. Specifically, via appropriate shaping of active surfaces 2942 of the electrodes 2940 and via appropriate application of voltages to the active surfaces 2942, configuring the electrode active surfaces 2942 with alternating shapes may facilitate generation of a quadrupole electric field while minimizing and / or eliminating associated parasitic 12-pole fields.

[0388] In some examples, the properties of multipole element 2900 may be characterized with reference to the relative magnitudes of the multipole field components generated by multipole element 2900. If the fringing fields are neglected, the potential of a multipole field of multiplicity m may be expressed as

[0389]

[0390] where m = 2 for a quadrupole field, m = 3 for a hexapole field, m = 6 for a dodecapole field, etc., and R is the inner radius of the multipole element. Thus, the quadrupole field potential is given by

[0391]

[0392] The 12-pole field potential is given by

[0393]

[0394] When a multipole element having eight identical electrodes arranged equidistant from the optical axis is excited to produce a quadrupole field given by equation (44), the multipole element will also produce a concomitant parasitic 12-pole field given by equation (45). Specifically, in such an example, the quadrupole multipole component V2 can be related to the 12-pole multipole component V6 of the parasitic 12-pole field as |V6 / V2|≈0.25.

[0395] In contrast, when multipole element 2900 is excited to produce a quadrupole field, quadrupole multipole component V2 can be related to 12-pole multipole component V6 of the parasitic 12-pole field as |V6 / V2|≤0.1. As used herein, characterizing the number of quadrupole and 12-pole multipole field components produced by a multipole element (e.g., multipole element 2900) |V6 / V2| can be referred to as a 12-pole to quadrupole component ratio. Multipole element 2900 can be any of a plurality of 12-pole to quadrupole component ratios, such as a 12-pole to quadrupole component ratio of at most 0.1, at most 0.05, at most 0.01, and / or at least 0.001. In practice, the specific shapes of electrodes 2940 in the first shape electrode subset 2960 and the second shape electrode subset 2962 can be specifically selected and / or configured to mitigate and / or minimize parasitic aberrations and / or 12-pole to quadrupole component ratios in this manner.

[0396] Similar to Fig.28The multipole element 2800, the electrodes 2940 of the multipole element 2900 may also be divided into a first side electrode subset 2952 and a second side electrode subset 2956, as described above with reference to Fig.28 As stated. Fig.29 As shown, the first side electrode subset 2952 and the second side electrode subset 2956 may include different numbers of electrodes 2940. Specifically, Fig.29 An example is shown in which a first side electrode subset 2952 includes five electrodes 2940 extending away from the central hole 2930 along a first lateral direction 2916 and in which a second side electrode subset 2956 includes three electrodes 2940 extending away from the central hole 2930 along a second lateral direction 2918. In this example, the multipole element 2900 exhibits mirror symmetry about a plane containing the beam axis 2930 and parallel to the second direction 2908.

[0397] Fig.30 3052 and the second side electrode subset 3056 are shown, except that the distribution of electrodes 3040 in the first side electrode subset 3052 and the second side electrode subset 3056 is substantially similar to Fig.29 An example of a multipole element 2900 of a multipole element 3000 is shown. Specifically, Fig.30 In the example of , each of the first side electrode subset 3052 and the second side electrode subset 3056 includes four electrodes 3040. In this example, the multipole element 3000 exhibits axial symmetry about the beam axis 3002.

[0398] Unless otherwise specified, Fig.29 The multi-pole element 2900 and Fig.30 All components of the multipole element 3000, labeled or not, shown may be Fig.28 The corresponding components of multipole element 2800 and / or share any suitable features, characteristics, properties, etc. with each other's corresponding components. For example, for Figure 29 to Figure 30 For those parts marked in the Fig.28 Components marked with reference numerals of the form "28XX" correspond.

[0399] Fig.31 An example of an assembly 3100 including a plurality of multipole elements 3110 axially aligned relative to a beam axis 3102 is shown. Fig.31 Each multipole element 3110 may represent an example of any suitable multipole element disclosed herein, such as Fig.26 The multi-pole element 2622, 2624 or 2626, Fig. 27 Multi-pole element 2700, Fig.28 Multi-pole components 2800, Fig.29 Multipole element 2900 or Fig.303000 of multipole elements.

[0400] exist Fig.31 In the example of FIG. 3 , the multipole element 3110 is configured to focus a charged particle beam 3150 traveling along a beam axis 3102 to a target focus location 3152, such as a sample (eg, Fig.26 In this example, the assembly 3100 and / or the plurality of multipole elements 3110 may be referred to as a multipole objective. As an example, the plurality of multipole elements 3110 may correspond to and / or represent Figure 22 to Figure 23 Multipole objective lens 2440 / 2540, objective lens multipole element 2242 / 2342 or Figure 24 to Figure 25 The objective lens multipole element 2442 / 2542 of the multipole objective lens 2240 / 2340. Fig.31 The assembly 3100 is shown as including four multipole elements 3110, but this is not required and it should be understood that reference is made herein to Fig.31 The described features and characteristics may also apply to similar and / or otherwise identical components including more than four multipole elements 3110 or less than four multipole elements 3110 .

[0401] like Fig.31 As shown, the multipole objective can be characterized by a working distance 3158 (e.g., as measured along the beam axis 3102) that separates the proximal multipole element 3154 from the target focus position 3152. Specifically, the proximal multipole element 3154 can refer to a multipole element 3110 that is positioned adjacent to the target focus position 3152 relative to the remaining multipole elements 3110 of the multipole objective 3100. For example, the proximal multipole element 3154 can correspond to and / or represent Figure 22 to Figure 23 The third objective multipole element 2248 / 2348 or Figure 24 to Figure 25 The fourth objective multipole element 2450 / 2550 of FIG. Additionally or alternatively, the proximal multipole element 3154 may correspond to and / or represent a multipole element configured for scanning and / or astigmatism correction of the charged particle beam 3150.

[0402] Fig.31 The multipole objective can also be characterized by an angular region or envelope defined relative to the beam axis 3102 and / or the target focus position 3152, and the multipole elements 3110 are spatially contained within the angular region or envelope. For example, Fig.31 The projection onto the xz plane (eg, reference Fig.26 A side view of a multipole objective lens on a xz plane (coordinate system), the xz plane containing the beam axis 3102, which may be referred to herein as the first plane 3164. Fig.31As shown, the plurality of multipole elements 3110 are completely contained within a first angular envelope 3160 defined in the first face 3164. Specifically, the first angular envelope 3160 represents an area of ​​the first face 3164 between two lines in the first face 3164 that intersect each other and the beam axis 3102 at the target focus location 3152 and subtend (e.g., are angled relative to each other) the first angle 3162.

[0403] refer to Fig.26 and Fig.31 , Fig.31 The first angle 3162 may be understood to represent and / or correspond to Fig.26 For example, the value of the free space angle 2618 may represent a maximum value of a first angle 3162 that characterizes a region (e.g., a first angle envelope 3160) within which the plurality of multipole elements 3110 must fit in order to accommodate the sample 2630 and the sample 2630. Fig.26 between the first exclusion zones 2606.

[0404] Generally speaking, for a given value of the first angle 3162, any dimension (e.g., as in Fig.31 The multipole element 3110 (measured in the x-direction of FIG. 31 ) can be contained within the first angular envelope 3160. However, in various examples, an aberration (e.g., spherical aberration) of the charged particle beam 3150 at the target focus position 3152 is related to (e.g., proportional to) the working distance 3158. Therefore, it is desirable to minimize the working distance 3158 to the extent permitted by other spatial constraints.

[0405] In certain examples, when first angle 3162 is at least 25 degrees, at least 35 degrees, at least 45 degrees, at least 55 degrees, at most 60 degrees, at most 50 degrees, at most 40 degrees, and / or at most 30 degrees, and working distance 3158 is at least 2 mm, at least 5 mm, at least 10 mm, at least 20 mm, at most 30 mm, at most 15 mm, at most 10 mm, at most 7 mm, and / or at most 3 mm, multipole element 3110 can be fully contained within first angular envelope 3160. In a specific example, when first angle is at most 50 degrees and working distance is at most 10 mm, multipole element 3110 can be fully contained within first angular envelope 3160. Fig.31One or more characteristics of the assembly 3100 may additionally or alternatively be characterized by and / or with reference to an aberration (e.g., spherical aberration) of the charged particle beam 3150 at a target focus location 3152. As an example, the plurality of multipole elements 3110 may be configured to operate as an objective lens to focus the charged particle beam 3150 to the target focus location 3152 with a third order spherical aberration of one or more of at most 5 mm, at most 3 mm, at most 2 mm, at most 1 mm, and / or at least 0.1 mm.

[0406] Thus, multipole elements 3110 may have any of a variety of features as disclosed herein to facilitate positioning multipole elements 3110 (e.g., at least proximal multipole elements 3154) proximate to target focus location 3152 while maintaining multipole elements 3110 within first angular envelope 3160. For example, each multipole element 3110 may have a plurality of features along Fig.31 A linear dimension in the x-direction that is small enough to allow each multipole element 3110 to be positioned ideally adjacent to a target focus position 3152 while maintaining each multipole element 3110 within a first angular envelope 3160 .

[0407] In various examples, this can be accomplished by configuring the multipole element 3110 to have a plurality of electrodes along a direction different from the plurality of electrodes along a direction. Fig.31 For example, multipole element 3110 may be formed by a first dimension (e.g., Figures 27 to 30 2706 / 2806 / 2906 / 3006) and a second dimension measured in the y direction transverse to the x and z directions (e.g., Figures 27 to 30 The second dimension 2704 / 2810 / 2910 / 3010) is characterized such that the second dimension is greater than the first dimension. In other words, the multipole element 3110 is configured such that a portion thereof (e.g., Figures 28 to 30 The electrode extensions 2840 / 284 / 3040) extending along the y-direction can help minimize the linear dimension of the multipole element 3110 along the x-direction.

[0408] Additionally or alternatively, and if Fig.31 As shown, each multipole element 3110 may have a non-surface structure, with a portion thereof extending partially along the axial direction. Specifically, Fig.31 An example is shown in which each multipole element 3110 includes a plurality of electrode active surfaces 3142 facing the central hole 3130 and a plurality of electrode extensions 3144 extending away from the corresponding electrode active surfaces 3142, as described above with reference to Figures 27 to 30 As discussed. Fig.31As shown, each electrode extension 3144 can be described as extending in a direction that extends away from the central hole 3130 partially along a radial direction 3112 that is perpendicular to the beam axis 3102 and partially along an axial direction 3114 that is parallel to the beam axis 3102. In other words, each electrode extension 3144 can be described as extending away from the corresponding electrode active surface 3142 along a direction that is angled relative to each of the radial direction 3112 and the axial direction 3114. Although Fig.31 The radial direction 3112 is shown as being parallel to the x-direction, but it should be understood that the radial direction 3112 may also be any other direction perpendicular to the beam axis 3102 .

[0409] In various examples, Figures 27 to 30 The multi-pole components 2700 / 2800 / 2900 / 3000 can Fig.31 The manner shown is partially angled away from the face configuration. For example, Figures 27 to 30 The electrode extensions of the multipole elements of any of the above may extend away from the corresponding electrode active surface in a direction that is not perpendicular to the beam axis, similar to Fig.31 Multipole element 3110.

[0410] Additionally or alternatively, each multipole element 3110 can be characterized by its different linear dimensions at different axial positions thereof. Fig.31 As shown, each multipole element 3110 can be described as extending along a direction parallel to the beam axis 3102 (e.g., along the axial direction 3114) between its proximal end region 3120 and its distal end region 3124. In some examples, the proximal end region 3120 is a region adjacent to the central hole 3130, and the distal end region 3124 is a region away from the central hole 3130. In some examples, and as Fig.31 As shown, each multipole element 3110 can be characterized by a first diameter 3122 at a proximal end region 3120 and a second diameter 3126 at a distal end region 3124, such that the second diameter 3126 is greater than the first diameter 3122. Each of the first diameter 3122 and the second diameter 3126 can be measured along a direction perpendicular to the beam axis 3102 (e.g., along a radial direction 3112). In such examples, the first diameter 3122 and the second diameter 3126 can be related in any suitable manner, such as to facilitate accommodating the multipole element 3110 within the first angular envelope 3160. As an example, the ratio of the second diameter 3126 to the first diameter 3122 can be at least 1.2:1, at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at most 4:1, at most 2.7:1, at most 2.3:1, at most 1.7:1, and / or at most 1.3:1.

[0411] Fig.31 The configuration shown can also facilitate forming electrical connections with each multipole element 3110 so as to supply the appropriate voltage to the electrodes 3140 of each multipole element 3110. For example, and as described above with reference to Figures 28 to 30 As discussed, the electrode extension 3144 of each electrode 3140 may include an electrical contact location 3146 that is configured to couple to an electrical lead 3192 (e.g., a wire) to supply a voltage to the corresponding electrode active surface 3142.

[0412] exist Fig.31 In the example of FIG. 31 , each electrode active surface 3142 is axially offset (e.g., spaced apart along axial direction 3114) from a corresponding electrical contact location 3146. This configuration can facilitate forming an electrical connection between the electrical lead 3192 and the electrical contact location 3146 in an area that is less spatially constrained than the proximal end region 3120 of each multipolar element 3110. In other words, because the electrical connection between the lead 3192 and the electrical contact location 3146 is substantially the same as that between the lead 3192 and the electrical contact location 3146, the electrical connection between the lead 3192 and the electrical contact location 3146 is substantially the same as that between the lead 3192 and the electrical contact location 3146. Fig.31 The linear range of the first angular envelope 3160 measured in the x-direction increases with increasing distance from the target focus position 3152, so when such a connection is formed at a position farther away from the target focus position 3152 relative to the electrode active surface 3142, spatial constraints and / or tolerances can be relaxed to form the electrical connection.

[0413] Fig.31 The assembly 3100 may also be characterized with reference to one or more linear dimensions of the multipole elements 3110 and / or their relative positions measured along the axial direction 3114. For example, each pair of adjacent multipole elements 3110 may be separated by a corresponding multipole element gap 3180. As an example, each multipole element gap 3180 may be at least 0.2 mm, at least 0.5 mm, at least 1 mm, at most 1.5 mm, at most 0.7 mm, and / or at most 0.3 mm. In various examples, the multipole element gaps 3180 characterizing the plurality of multipole elements 3110 may be different from one another and / or may be controlled and / or configured to limit aberrations of the charged particle beam 2050 at the target focus position 3152.

[0414] Additionally or alternatively, each multipole element 3110 can be characterized by a corresponding multipole element length 3182 as measured along the axial direction 3114. Specifically, in some examples, each multipole element 3110 includes a central region 3186 defining a central aperture 3130 (e.g., excluding electrode extensions 3144 extending axially away from the central aperture 3130), and the multipole element length 3182 is measured in the central region 3186 of the multipole element 3110. As an example, each multipole element length 3182 can be at least 2 mm, at least 5 mm, at least 10 mm, at most 15 mm, at most 10 mm, at most 7 mm, and / or at most 3 mm. In various examples, the multipole element lengths 3182 characterizing the plurality of multipole elements 3110 can be different from one another and / or can be controlled and / or configured to control aberrations of the charged particle beam 2050 at the target focus position 3152.

[0415] Additionally or alternatively, the plurality of multipole elements 3110 may be characterized by their total stack length 3184. For example, and as Fig.31 As shown, the plurality of multipole elements 3110 may include a distal multipole element 3156 distal to the target focus position 3152 relative to the remaining multipole elements 3156, and a stack length 3184 may be measured along the axial direction 3114 between the proximal multipole element 3154 and the distal multipole element 3110 (e.g., between the central regions 3186 thereof). The stack length 3184 may thus be equal to the sum of the multipole element length 3182 of the multipole elements 3110 and the multipole element gap 3180 separating each pair of adjacent multipole elements 3110. By way of example, the stack length 3184 may be at least 15 mm, at least 20 mm, at least 25 mm, at least 30 mm, at least 35 mm, at least 40 mm, at most 50 mm, at most 37 mm, at most 32 mm, at most 27 mm, at most 22 mm, and / or at most 17 mm.

[0416] In various examples, Fig.31 The features of the construction of can be characterized by a ratio of one or more dimensions of the plurality of multipole elements 3110 to the working distance 3358. For example, the plurality of multipole elements can be positioned and / or configured such that the ratio of the working distance 3158 of each multipole element 3110 to the multipole element length 3182 is at least 1:5, at least 1:2, at least 1:1, at least 2:1, at least 5:1, at least 10:1, at least 20:1, at most 30:1, at most 15:1, at most 7:1, at most 3:1, at most 1:1, and / or at most 1:3. Additionally or alternatively, the plurality of multipole elements can be positioned and / or configured such that the ratio of the stack length 3184 to the working distance 3158 is at least 1:1, at least 2:1, at least 5:1, at least 10:1, at most 20:1, at most 7:1, and / or at most 3:1.

[0417] Fig.32 An assembly 3200 is shown that includes a plurality of multipole elements 3210 and a lens housing 3290 that surrounds the plurality of multipole elements 3210. In addition to the presence of the lens housing 3290, Fig.32 The components of 3200 and Fig.31 Components 3100 are substantially the same. Specifically, unless otherwise specified, Fig.32 All shown components, marked or not, may be Fig.31 The corresponding components of share any suitable features, characteristics, properties, etc. For example, for Fig.32 For those components marked in FIG. 1 , components marked with reference numerals of the form "32XX" are intended to be the same as those marked in FIG. Fig.31 The parts marked with reference numerals of the form "31XX" correspond to the parts marked with reference numerals of the form "31XX".

[0418] Fig.32 The lens housing 3290 can be configured to shield, support and / or otherwise assemble the plurality of multipole elements 3210 so as to position the multipole elements 3210 relative to the target focus position 3252. Thus, the lens housing 3290 can be tapered and / or frusto-conical and / or can be characterized by a taper angle 3294 such that when the multipole elements 3210 are operably positioned relative to the target focus position 3252, the lens housing 3910 is also completely contained within the first angular envelope 3260. For example, the taper angle 3294 can be less than or equal to the first angle 3262.

[0419] Fig.33 An assembly 3300 including a plurality of multipole elements 3310 is shown in side view, which projects the multipole elements 3310 onto a yz plane containing a beam axis 3302 (eg, with reference to FIG. 3304 ). Fig.26 and / or Fig.31 coordinate system). Fig.33 As shown, the yz surface may additionally or alternatively be referred to as the second surface 3374. Thus, Fig.33 The second side 3374 is perpendicular to Fig.31 The first side 3164. In this way, Fig.33 can be described as representing the Fig.31 Component 3100.

[0420] Unless otherwise specified, Fig.33 All components shown, marked or not, may be Fig.31 The corresponding components of share any suitable features, characteristics, properties, etc. For example, for Fig.33 For those components marked in FIG. 1 , components marked with reference numerals of the form "33XX" are intended to be the same as those marked in FIG. Fig.31 The parts marked with reference numerals of the form "31XX" correspond to the parts marked with reference numerals of the form "31XX".

[0421] exist Fig.33 In the example of , multipole element 3310 is completely contained within second angular envelope 3370, which is defined in second face 3374. Fig.31 3352, and second angular envelope 3370 subtends second angle 3372 as measured between lines defining second angular envelope 3370 therebetween and intersecting at target focus position 3352. In particular examples, multipole element 3310 can be fully contained within second angular envelope 3370 when second angle 3372 is at least 25 degrees, at least 35 degrees, at least 45 degrees, at least 55 degrees, at most 60 degrees, at most 50 degrees, at most 40 degrees, and / or at most 30 degrees, and working distance 3358 is at least 2 mm, at least 5 mm, at least 10 mm, at least 20 mm, at most 30 mm, at most 15 mm, at most 10 mm, at most 7 mm, and / or at most 3 mm.

[0422] In some examples, Fig.33 The second angle 3372 may be at least substantially equal to Fig.31 The first angle 3162. In such an example, Fig.31 The first angle envelope is 3160 and Fig.33 The second angular envelope 3370 can be described as representing a cross-section of the conical envelope viewed in the transverse plane.

[0423] In other examples, Fig.33 The second angle 3727 may be greater than Fig.31 The first angle 3162. For example, referring to Fig.26 , the constraints on the assembly of a multipole element (e.g., third objective multipole element 2626) within free space 2616 may correspond to constraints on the size of the multipole element in the x-direction, while the size of the multipole element in the y-direction may be relatively (or completely) unconstrained.

[0424] The second angle 3372, which is increased relative to the first angle 3162, can allow the multipole element 3310 to have a Fig.31 The linear dimension of the x-direction is along Fig.33 For example, for a given value of working distance 3158 / 3358, an increase in second angle 3372 characterizing second angular envelope 3370 may correspond to an increase in the linear size of multipole element 3310 that may be contained within second angular envelope 3370.

[0425] In some examples, and as discussed above, Fig.33 The multipole element 3310 may correspond to and / or represent Fig.31The multipole element 3110, such as the portion of the multipole element 3110 / 3310 projected onto and / or intersecting the second surface 3374. For example, the multipole element 3110 / 3310 may include a portion away from Fig.31 The electrode extension 3144 is angled in the radial direction 3112 of the beam axis 3302, and the electrode extension 3344 is perpendicular to the beam axis 3302. Alternatively, in some examples, the electrode extension 3144 / 3344 can be arranged in each of the first face 3164 and the second face 3374. Fig.31 In other examples, the electrode extension 3144 / 3344 may be bent away from the radial direction 3112 in each of the first face 3164 and the second face 3374. Fig.33 The manner shown is along the radial direction 3112 (e.g., along Fig.33 y direction).

[0426] Fig.34 An assembly 3400 including a plurality of multipole elements 3410 and a lens housing 3490 surrounding the plurality of multipole elements 3410 is shown in side view, projecting the multipole elements 3410 onto a yz plane containing a beam axis 3402 (eg, reference Fig.26 or Figure 31 to Figure 33 In the coordinate system of FIG. 347 , the yz plane may also be referred to as the second plane 3474. In this way, Fig.34 can be described as representing the Fig.32 Component 3200.

[0427] In addition to the presence of lens housing 3490, Fig.34 Components 3400 with Fig.33 The components 3300 are substantially the same as Fig.31 and Fig.33 In a similar way to the relationship between , except viewed in the yz plane instead of the xz plane, Fig.34 The components of 3400 are also Fig.32 Components 3200 are substantially the same. Unless otherwise specified, Fig.34 All components shown, marked or not, may be Figure 31 to Figure 33 The corresponding components of share any suitable features, characteristics, properties, etc. For example, for Fig.34 For those parts marked in FIG. 1 , parts marked with reference numerals of the form "34XX" are intended to be the same as those marked in FIG. Figure 31 to Figure 33 Components marked with reference numerals in the form “31XX” / “32XX” / “33XX” correspond.

[0428] Compare Fig.32 and Fig.34, it can be seen that an increase in second angle 3472 characterizing second angular envelope 3470 relative to first angle 3262 characterizing first angular envelope 3260 may allow lens housing 3490 to be formed with a correspondingly larger taper angle 3494. Specifically, in some examples, Fig.32 The lens housing 3290 and Fig.34 The lens housing 3490 may represent a transverse cross-section of a common lens housing that may have a greater taper angle 3494 in the second face 3474 than in the first face 3264. For example, the lens housing may have a three-dimensional shape similar to a flat cone (e.g., having an elliptical cross-section in the xy plane) and / or any other shape that can be characterized by different taper angles in the transverse faces. In such examples, Fig.32 The cone angle 3294 of the lens housing 3290 in the first face 3264 shown can be described as a first cone angle 3294, and Fig.34 The cone angle 3494 of the lens housing 3490 in the second face 3474 shown can be described as a second cone angle 3494. Fig.26 As discussed above, this configuration can facilitate positioning the lens housing in a direction corresponding to a smaller cone angle (e.g., along Fig.26 and Fig.32 The multipole element is constrained in free space (in the x-direction), thereby enabling the multipole element to be positioned desirably close to the target focus position.

[0429] General considerations

[0430] As used in this application and in the claims, the singular forms "a", "an", and "the" include plural forms unless the context clearly dictates otherwise. In addition, the term "comprising" means "including". Furthermore, the term "coupled" does not exclude the presence of intervening elements between the coupled items.

[0431] As used herein, the term "substantially" refers to the listed values ​​and / or properties and any values ​​and / or properties that are at least 75% of the listed values ​​and / or properties. Equivalently, the term "substantially" refers to the listed values ​​and / or properties and any values ​​and / or properties that differ from the listed values ​​and / or properties by at most 25%. For example, "substantially equal" refers to completely equal amounts, as well as amounts that differ from each other by at most 25%.

[0432] The systems, devices, and methods described herein should not be construed as limiting in any way. Rather, the present disclosure relates to all novel and non-obvious features and aspects of the various disclosed examples, either individually or in various combinations and sub-combinations formed with each other. The disclosed systems, methods, and devices are not limited to any particular aspect or feature or combination thereof, nor do the disclosed systems, methods, and devices require the presence of any one or more specific advantages or solutions to 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.

[0433] In various examples described herein, a module (e.g., component) may be "programmed" to perform certain operations or provide certain functionality, indicating that computer executable instructions for the module may be executed to perform such operations, cause such operations to be performed, or otherwise provide such functionality. Although functionality described with respect to a software component, module, or engine may be performed as a discrete software unit (e.g., a procedure, function, class method), it need not be implemented as a discrete unit. That is, functionality may be incorporated into a larger or more general program, such as one or more lines of code in a larger or general program.

[0434] The principles of the disclosed technology have been described and illustrated with reference to the illustrated examples, and it should be appreciated that the illustrated examples may be modified in arrangement and detail without departing from such principles. For example, the example elements executed in software may be implemented in hardware, and vice versa. In addition, the techniques from any example may be combined with the techniques described in any one or more of the other examples. It should be understood that processes and functions such as those described with reference to the illustrated examples may be implemented in a single hardware or software module, or separate modules may be provided. The above specific arrangements are provided for ease of description, and other arrangements may be used.

[0435] Additional Embodiments of the Disclosed Technology

[0436] In view of the above specific implementation of the disclosed subject matter, the present application discloses the additional embodiments listed below. It should be noted that one feature of a separate example or one or more features of the example adopted in combination and optionally in combination with one or more features of one or more additional examples are also additional examples belonging to the disclosure of the present application.

[0437] Embodiment 1. A device, comprising:

[0438] a plurality of electrostatic elements configured to deflect an incident charged particle beam along an alpha-shaped path,

[0439] Wherein the plurality of electrostatic elements comprises a plurality of electrostatic multipole elements configured to at least partially correct axial chromatic aberration of the charged particle beam.

[0440] Example 2. An apparatus according to any embodiment herein, in particular Example 1, wherein the apparatus further comprises a deflector assembly, wherein the deflector assembly comprises a corrector electrostatic prism and the plurality of electrostatic multipole elements, wherein the deflector assembly is configured to deflect the charged particle beam along the deflector optical axis, and wherein the deflector assembly is configured to at least partially correct the axial chromatic aberration in the charged particle beam using two or more hexapole fields generated in the corrector electrostatic prism.

[0441] Embodiment 3. The device according to any embodiment herein, in particular any one of embodiments 1 to 2, wherein the plurality of electrostatic multipole elements comprises:

[0442] a first hexapole generating element configured to generate a first hexapole field;

[0443] a second hexapole generating element configured to generate a second hexapole field; and

[0444] A third hexapole generating element is configured to generate a third hexapole field.

[0445] Embodiment 4. A device according to any embodiment herein, in particular any one of embodiments 2 to 3, wherein at least two electrostatic multipole elements of the plurality of electrostatic multipole elements are at least partially contained within the corrector electrostatic prism.

[0446] Embodiment 5. A device according to any embodiment herein, in particular any one of embodiments 1 to 4, wherein the deflector optical axis is a bending axis.

[0447] Embodiment 6. A device according to any embodiment herein, in particular any one of embodiments 1 to 5, wherein the deflector optical axis is α-shaped.

[0448] Embodiment 7. A device according to any embodiment herein, in particular any one of embodiments 2 to 6, wherein a portion of the deflector optical axis extending within the corrector electrostatic prism follows a circular path.

[0449] Embodiment 8. A device according to any embodiment herein, in particular any one of embodiments 2 to 7, wherein the position of the portion along the deflector optical axis extending within the corrector electrostatic prism is characterized by a prism angle φ, which can be 0 and φ max Any value in between.

[0450] Embodiment 9. A device according to any embodiment herein, in particular embodiment 8, wherein the prism angle φ=0 corresponds to the position where the charged particle beam enters the corrector electrostatic prism along the deflector optical axis, and wherein the prism angle φ=φ max Corresponds to the position where the charged particle beam leaves the corrector electrostatic prism along the deflector optical axis.

[0451] Embodiment 10. A device according to any embodiment herein, in particular any one of embodiments 8 to 9, wherein the prism angle φ max Equal to or approximately equal to 270 degrees.

[0452] Embodiment 11. A device according to any embodiment herein, in particular any one of embodiments 2 to 10, wherein the corrector electrostatic prism is configured to deflect the charged particle beam through an angle equal to or approximately equal to 270 degrees.

[0453] Embodiment 12. A device according to any embodiment herein, in particular any one of embodiments 2 to 11, wherein at least a subset of the plurality of electrostatic multipole elements are positioned within the corrector electrostatic prism.

[0454] Embodiment 13. The device according to any embodiment herein, in particular any one of embodiments 2 to 12, further comprising:

[0455] an incident electrostatic prism configured to direct the charged particle beam from an optical column axis toward the deflector optical axis; and

[0456] An exit electrostatic prism is configured to direct the charged particle beam from the deflector optical axis toward the optical column axis.

[0457] Embodiment 14. A device according to any embodiment herein, in particular Embodiment 13, wherein each of the incident electrostatic prism and the exit electrostatic prism is configured to deflect the charged particle beam through an angle equal to or approximately equal to 45 degrees.

[0458] Embodiment 15. A device according to any embodiment herein, in particular any one of embodiments 13 to 14, wherein one or both of the incident electrostatic prism and the exit electrostatic prism are dual focusing prisms.

[0459] Embodiment 16. A device according to any embodiment herein, in particular any one of embodiments 13 to 15, wherein the plurality of electrostatic elements further comprises a first quadrupole generating element configured to generate a first quadrupole field and a second quadrupole generating element configured to generate a second quadrupole field, wherein the first quadrupole generating element is defined by the incident electrostatic prism or coupled to one or both of the incident electrostatic prisms, and wherein the second quadrupole generating element is defined by the exit electrostatic prism or coupled to one or both of the exit electrostatic prisms.

[0460] Embodiment 17. The device according to any embodiment herein, in particular any one of embodiments 13 to 16, wherein the device is configured to selectively operate in each of the following:

[0461] a calibration mode, wherein the incident electrostatic prism directs the charged particle beam toward the deflector optical axis; and

[0462] Direct-axis mode, in which the charged particle beam bypasses the deflector assembly.

[0463] Embodiment 18. The device according to any embodiment herein, in particular any one of embodiments 13 to 17, wherein the plurality of electrostatic elements comprises:

[0464] a first hexapole generating element configured to generate a first hexapole field;

[0465] a second hexapole generating element configured to generate a second hexapole field;

[0466] a third hexapole generating element, the third hexapole generating element being configured to generate a third hexapole field;

[0467] a first quadrupole generating element configured to generate a first quadrupole field; and

[0468] a second quadrupole generating element, the second quadrupole generating element being configured to generate a second quadrupole field,

[0469] Wherein the first quadrupole generating element is positioned between the incident electrostatic prism and the first hexapole generating element along the deflector optical axis, and wherein the second quadrupole generating element is positioned between the third hexapole generating element and the exit electrostatic prism along the deflector optical axis.

[0470] Embodiment 19. A device according to any embodiment herein, in particular any one of embodiments 2 to 18, wherein the plurality of electrostatic elements further comprises a first quadrupole generating element configured to generate a first quadrupole field and a second quadrupole generating element configured to generate a second quadrupole field, and wherein each of the first quadrupole generating element and the second quadrupole generating element is a tunable quadrupole generating element.

[0471] Embodiment 20. A device according to any embodiment herein, in particular any one of embodiments 2 to 19, wherein the plurality of electrostatic elements further comprises a first quadrupole generating element configured to generate a first quadrupole field and a second quadrupole generating element configured to generate a second quadrupole field, and wherein each of the first quadrupole generating element and the second quadrupole generating element is spaced apart from the corrector electrostatic prism.

[0472] Embodiment 21. A device according to any embodiment herein, in particular any one of embodiments 2 to 20, wherein the plurality of electrostatic elements further comprises a first quadrupole generating element configured to generate a first quadrupole field and a second quadrupole generating element configured to generate a second quadrupole field, and wherein each of the first quadrupole generating element and the second quadrupole generating element is coupled to the corrector electrostatic prism.

[0473] Embodiment 22. A device according to any embodiment herein, in particular any one of embodiments 2 to 21, wherein the plurality of electrostatic elements further comprises a first quadrupole generating element configured to generate a first quadrupole field and a second quadrupole generating element configured to generate a second quadrupole field, and wherein each of the first quadrupole generating element and the second quadrupole generating element is at least partially contained within the corrector electrostatic prism.

[0474] Embodiment 23. A device according to any embodiment herein, in particular any one of embodiments 2 to 22, wherein the corrector electrostatic prism includes a corrector prism body, the corrector prism body having a first corrector prism electrode and a second corrector prism electrode radially positioned outside the first corrector prism electrode, wherein the first corrector prism electrode and the second corrector prism electrode define an electrode gap therebetween, and wherein the deflector optical axis extends within the electrode gap.

[0475] Embodiment 24. A device according to any embodiment herein, in particular Embodiment 23, wherein the corrector electrostatic prism is configured such that when a first electrode voltage is applied to the first corrector prism electrode and a second electrode voltage is applied to the second corrector prism electrode, the corrector electrostatic prism generates an electrostatic deflection field, which guides the charged particle beam to travel along the deflector optical axis through the corrector electrostatic prism.

[0476] Embodiment 25. A device according to any embodiment herein, in particular any one of embodiments 23 to 24, wherein the first corrector prism electrode comprises a first electrode outer surface, the first electrode outer surface defining a first electrode recess extending partially along a direction parallel to the deflector optical axis, wherein the second corrector prism electrode comprises a second electrode outer surface, the second electrode outer surface defining a second electrode recess extending partially along a direction parallel to the deflector optical axis, and wherein at least one electrostatic multipole element of the plurality of electrostatic multipole elements is at least partially positioned within each of the first electrode recess and the second electrode recess.

[0477] Embodiment 26. The device according to any embodiment herein, in particular embodiment 25, wherein, for one or more electrostatic multipole elements of the plurality of electrostatic multipole elements, the electrostatic multipole element comprises:

[0478] a first hexapole electrode;

[0479] a second sextupole electrode;

[0480] a third sextupole electrode;

[0481] fourth sextupole electrode;

[0482] a fifth sextupole electrode; and

[0483] The sixth sextupole electrode,

[0484] Wherein the first hexapole electrode, the second hexapole electrode and the third hexapole electrode are at least partially received in the second electrode recess, and wherein the fourth hexapole electrode, the fifth hexapole electrode and the sixth hexapole electrode are at least partially received in the first electrode recess.

[0485] Embodiment 27. The device according to any embodiment herein, in particular any one of embodiments 2 to 26, wherein the plurality of electrostatic elements comprises:

[0486] a first hexapole generating element configured to generate a first hexapole field;

[0487] a second hexapole generating element configured to generate a second hexapole field; and

[0488] A third hexapole generating element is configured to generate a third hexapole field.

[0489] Embodiment 28. A device according to any embodiment herein, in particular embodiment 27, wherein the second hexapole generating element is positioned adjacent to the midpoint of the deflector optical axis within the corrector electrostatic prism.

[0490] Embodiment 29. A device according to any embodiment herein, in particular any one of embodiments 27 to 28, wherein the position of a portion along the deflector optical axis extending within the corrector electrostatic prism is characterized by a prism angle φ varying from 0 degrees to 270 degrees, and wherein the second hexapole generating element is positioned within the corrector electrostatic prism at a prism angle of φ = 135 degrees.

[0491] Embodiment 30. The device according to any embodiment herein, in particular any one of embodiments 27 to 29, wherein each of the first hexapole generating element and the third hexapole generating element is angularly equidistant from the second hexapole generating element.

[0492] Embodiment 31. A device according to any embodiment herein, in particular any one of embodiments 27 to 30, wherein each of the first hexapole generating element and the third hexapole generating element is positioned adjacent to a position along the deflector optical axis corresponding to a linear focus of the charged particle beam.

[0493] Embodiment 32. A device according to any embodiment herein, in particular any one of embodiments 2 to 31, wherein the second hexapole generating element is positioned adjacent to a position along the deflector optical axis corresponding to a line focus of the charged particle beam.

[0494] Embodiment 33. A device according to any embodiment herein, in particular any one of embodiments 2 to 32, wherein the corrector electrostatic prism is configured to generate at least a portion of an electrostatic deflection field comprising a prismatic hexapole field.

[0495] Embodiment 34. A device according to any embodiment herein, in particular embodiment 33, wherein the position of the portion extending within the corrector electrostatic prism along the deflector optical axis is characterized by a prism angle φ, wherein the position within the corrector electrostatic prism away from the deflector optical axis is characterized by the prism angle φ, a radial distance x away from the deflector optical axis, and a lateral distance y away from the deflector optical axis, and wherein the magnitude of the prismatic hexapole field within the corrector electrostatic prism is a function of x and y and is constant with respect to φ.

[0496] Embodiment 35. A device according to any embodiment herein, in particular any one of embodiments 2 to 34, wherein the corrector electrostatic prism comprises a first corrector prism electrode and a second corrector prism electrode positioned radially outside the first corrector prism electrode, wherein the first corrector prism electrode comprises a first electrode outer surface facing the second corrector prism electrode, wherein the second corrector prism electrode comprises a second electrode inner surface facing the first corrector prism electrode, and wherein each of the first electrode outer surface and the second electrode inner surface has a substantially constant cross-sectional profile within the corrector electrostatic prism away from each electrostatic multipole element when viewed in a direction perpendicular to the deflector optical axis.

[0497] Embodiment 36. A device according to any embodiment herein, in particular any one of embodiments 33 to 35, wherein the position of the portion along the deflector optical axis extending within the corrector electrostatic prism is characterized by a prism angle φ, and wherein the magnitude of the prismatic hexapole field within the corrector electrostatic prism varies with φ.

[0498] Embodiment 37. A device according to any embodiment herein, in particular embodiment 36, wherein the magnitude of the prism hexapole field is proportional to a hexapole parameter p that varies with the prism angle φ.

[0499] Embodiment 38. The device according to any embodiment herein, in particular embodiment 37, wherein the hexapole parameter is piecewise constant as a function of:

[0500] (i) p = p1, 0 < φ ≤ φ1;

[0501] (ii) p = p2, φ1 < φ ≤ φ2;

[0502] (iii) p = p3, φ2 < φ ≤ φ3;

[0503] (iv) p = p3, φ3 < φ ≤ φ4;

[0504] (v) p = p2, φ4 < φ ≤ φ5; and

[0505] (vi)p=p1,φ5<φ≤φ6.

[0506] Embodiment 39. The device according to any embodiment herein, in particular embodiment 38, wherein φ3=φ6 / 2.

[0507] Embodiment 40. A device according to any embodiment herein, in particular any one of embodiments 35 to 39, wherein the first corrector prism electrode includes a first electrode outer surface facing the second corrector prism electrode, wherein the first electrode outer surface defines a first electrode groove extending along a direction parallel to the deflector optical axis, wherein the second corrector prism electrode includes a second electrode inner surface facing the first corrector prism electrode, and wherein the second electrode inner surface defines a second electrode groove extending along a direction parallel to the deflector optical axis.

[0508] Embodiment 41. A device according to any embodiment herein, in particular Embodiment 40, wherein the corrector electrostatic prism is configured such that when a first electrode voltage is applied to the first corrector prism electrode and a second electrode voltage is applied to the second corrector prism electrode, the first electrode groove and the second electrode groove generate a hexapole field within the corrector electrostatic prism.

[0509] Embodiment 42. A device according to any embodiment herein, in particular any one of embodiments 40 to 41, wherein the corrector electrostatic prism has a corrector prism beam radius as measured between the center of the first corrector prism electrode and the deflector optical axis, wherein the first electrode groove has a first electrode groove depth as measured along a radial direction parallel to the corrector prism beam radius, wherein the second electrode groove has a second electrode groove depth as measured along the radial direction, and wherein each of the first electrode groove depth and the second electrode groove depth is at most 1 / 50 of the corrector prism beam radius.

[0510] Embodiment 43. A device according to any embodiment herein, in particular any one of embodiments 40 to 42, wherein the position of a portion along the deflector optical axis extending within the corrector electrostatic prism is characterized by a prism angle φ, and wherein one or more dimensions of one or both of the first electrode groove and the second electrode groove vary with the prism angle.

[0511] Embodiment 44. The device according to any embodiment herein, in particular any one of embodiments 1 to 43, wherein the plurality of electrostatic multipole elements comprises:

[0512] A first six-pole generating element, wherein the first six-pole generating element is configured to generate a first six-pole generating element.

[0513] polar field;

[0514] A second six-pole generating element, wherein the second six-pole generating element is configured to generate a second six-pole generating element.

[0515] polar field;

[0516] A third six-pole generating element is configured to generate a third six-pole generating element.

[0517] polar field; and

[0518] A fourth hexapole generating element is configured to generate a fourth hexapole field.

[0519] Example 45. An apparatus according to any embodiment herein, in particular Example 44, wherein the apparatus further comprises a deflector assembly, wherein the deflector assembly comprises a corrector electrostatic prism and the plurality of electrostatic multipole elements, wherein the deflector assembly defines a deflector optical axis, and wherein the deflector assembly is configured to at least partially correct axial chromatic aberration in the charged particle beam as the charged particle beam travels along the deflector optical axis.

[0520] Embodiment 46. The device according to any embodiment herein, in particular Embodiment 45, wherein each of the second hexapole generating element and the third hexapole generating element is at least partially positioned within the corrector electrostatic prism.

[0521] Embodiment 47. A device according to any embodiment herein, in particular any one of embodiments 45 to 46, wherein each of the second hexapole generating element and the third hexapole generating element is positioned adjacent to a position along the deflector optical axis corresponding to a line focus of the charged particle beam.

[0522] Embodiment 48. A device according to any embodiment herein, in particular any one of embodiments 2 to 47, wherein the corrector electrostatic prism is configured to produce a point focus of the charged particle beam near the mid-plane position of the deflector optical axis within the corrector electrostatic prism.

[0523] Embodiment 49. A device according to any embodiment herein, in particular any one of embodiments 2 to 48, wherein the corrector electrostatic prism is configured to act as a monochromator.

[0524] Embodiment 50. A device according to any embodiment herein, in particular any one of embodiments 2 to 49, wherein the device further comprises an energy selection slit, wherein the energy selection slit is positioned adjacent to the middle plane position of the deflector optical axis within the corrector electrostatic prism.

[0525] Embodiment 51. A device, comprising:

[0526] A plurality of electrostatic elements configured to deflect the

[0527] emitting charged particle beams;

[0528] Wherein the plurality of electrostatic elements comprises a plurality of electrostatic multipole elements configured to at least partially correct axial chromatic aberration of the charged particle beam.

[0529] Embodiment 52. The device according to any embodiment herein, in particular embodiment 51, further comprising:

[0530] a deflector assembly comprising a plurality of corrector electrostatic prisms and the plurality of electrostatic multipole elements,

[0531] wherein the plurality of corrector electrostatic prisms comprises:

[0532] The first electrostatic prism;

[0533] A second electrostatic prism;

[0534] a third electrostatic prism; and

[0535] The fourth electrostatic prism,

[0536] The plurality of electrostatic multipole elements include:

[0537] a first multipole element configured to generate a first hexapole field;

[0538] a second multipole element configured to generate a second hexapole field;

[0539] a third multipole element configured to generate a third hexapole field;

[0540] Wherein the deflector assembly defines a deflector optical axis, and wherein the deflector assembly is configured to at least partially correct axial chromatic aberration in the charged particle beam as the charged particle beam travels along the deflector optical axis.

[0541] Embodiment 53. A device according to any embodiment herein, in particular embodiment 52, wherein at least a portion of the deflector optical axis is curved.

[0542] Embodiment 54. A device according to any embodiment herein, in particular any one of embodiments 52 to 53, wherein the deflector optical axis is Ω-shaped.

[0543] Embodiment 55. A device according to any embodiment herein, in particular any one of embodiments 52 to 54, wherein each of the first electrostatic prism, the second electrostatic prism, the third electrostatic prism and the fourth electrostatic prism is configured to deflect the charged particle beam through an angle equal to or approximately equal to 90 degrees.

[0544] Embodiment 56. A device according to any embodiment herein, in particular any one of embodiments 52 to 55, wherein the second electrostatic prism and the third electrostatic prism are fixedly coupled to each other.

[0545] Embodiment 57. A device according to any embodiment herein, in particular any one of embodiments 52 to 56, wherein the first electrostatic prism and the fourth electrostatic prism are fixedly coupled to each other.

[0546] Embodiment 58. A device according to any embodiment herein, in particular any one of embodiments 52 to 57, wherein one or more of the first electrostatic prism, the second electrostatic prism, the third electrostatic prism or the fourth electrostatic prism is a dual focusing prism.

[0547] Embodiment 59. A device according to any embodiment herein, in particular any one of embodiments 52 to 58, wherein the plurality of electrostatic multipole elements are arranged in a mirror-symmetrical configuration with respect to the mid-plane position of the deflector optical axis within the deflector assembly.

[0548] Embodiment 60. A device according to any embodiment herein, in particular embodiment 59, wherein the second multipole element is a central multipole element positioned adjacent to the mid-plane position of the deflector optical axis within the deflector assembly, and wherein the first multipole element and the third multipole element are arranged in a mirror-symmetrical configuration with respect to the second multipole element.

[0549] Embodiment 61. A device according to any embodiment herein, in particular any one of embodiments 52 to 60, wherein the deflector assembly is configured to produce a linear focus of the charged particle beam, and wherein the second multipole element is positioned adjacent to a position along the deflector optical axis corresponding to the linear focus of the charged particle beam.

[0550] Embodiment 62. A device according to any embodiment herein, in particular any one of embodiments 52 to 61, wherein the first multipole element is further configured to generate a first element quadrupole field, and wherein the third multipole element is further configured to generate a third element quadrupole field.

[0551] Embodiment 63. The device according to any embodiment herein, in particular embodiment 62, wherein the deflector assembly is configured such that during operational use of the device:

[0552] The first hexapole field and the first element quadrupole field at least partially overlap; and

[0553] The third hexapole field and the third element quadrupole field at least partially overlap.

[0554] Embodiment 64. A device according to any embodiment herein, in particular any one of embodiments 52 to 63, wherein each of the first multipole element, the second multipole element and the third multipole element is a tunable multipole element.

[0555] Embodiment 65. The device according to any embodiment herein, in particular any one of embodiments 52 to 64, wherein the plurality of electrostatic multipole elements further comprises:

[0556] a fourth multipole element configured to generate a fourth hexapole field; and

[0557] A fifth multipole element is configured to generate a fifth sextupole field.

[0558] Embodiment 66. The device according to any embodiment herein, in particular embodiment 65, wherein the fourth multipole element and the fifth multipole element are arranged in a mirror-symmetric configuration with respect to the second multipole element.

[0559] Embodiment 67. A device according to any embodiment herein, in particular any one of embodiments 65 to 66, wherein the fourth multipole element is further configured to generate a fourth element quadrupole field, and wherein the fifth multipole element is further configured to generate a fifth element quadrupole field.

[0560] Embodiment 68. A device according to any embodiment herein, in particular Embodiment 67, wherein the fourth hexapole field and the fourth element quadrupole field at least partially overlap, and wherein the fifth hexapole field and the fifth element quadrupole field at least partially overlap.

[0561] Embodiment 69. The device according to any embodiment herein, in particular any one of embodiments 65 to 68, wherein each of the fourth multipole element and the fifth multipole element is a tunable multipole element.

[0562] Embodiment 70. The device according to any embodiment herein, in particular any one of embodiments 52 to 64, wherein the plurality of electrostatic multipole elements further comprises:

[0563] a fourth multipole element configured to generate a fourth element quadrupole field;

[0564] and

[0565] A fifth multipole element is configured to generate a fifth-element quadrupole field.

[0566] Embodiment 71. The device according to any embodiment herein, in particular Embodiment 70, wherein each of the fourth multipole element and the fifth multipole element is a tunable multipole element.

[0567] Embodiment 72. The device according to any embodiment herein, in particular any one of embodiments 52 to 71, wherein the plurality of electrostatic multipole elements further comprises:

[0568] a sixth multipole element configured to generate a sixth element quadrupole field;

[0569] a seventh multipole element configured to generate a seventh element quadrupole field;

[0570] an eighth multipole element configured to generate an eighth element quadrupole field;

[0571] and

[0572] A ninth multipole element is configured to generate a ninth element quadrupole field.

[0573] Embodiment 73. The device according to any embodiment herein, in particular Embodiment 72, wherein each of the sixth multipole element, the seventh multipole element, the eighth multipole element and the ninth multipole element is a fixed multipole element.

[0574] Embodiment 74. A device according to any embodiment herein, in particular any one of embodiments 72 to 73, wherein the first electrostatic prism comprises the sixth multipole element and the seventh multipole element.

[0575] Embodiment 75. A device according to any embodiment herein, in particular any one of embodiments 72 to 74, wherein each of the sixth multipole element and the seventh multipole element is coupled to the first electrostatic prism.

[0576] Embodiment 76. A device according to any embodiment herein, in particular any one of embodiments 72 to 75, wherein the fourth electrostatic prism comprises the eighth multipole element and the ninth multipole element.

[0577] Embodiment 77. A device according to any embodiment herein, in particular any one of embodiments 72 to 76, wherein each of the eighth multipole element and the ninth multipole element is coupled to the fourth electrostatic prism.

[0578] Embodiment 78. A charged particle microscope system, the charged particle microscope system comprising:

[0579] a charged particle source configured to emit a charged particle beam toward the sample;

[0580] and

[0581] A light column configured to focus the charged particle beam onto the sample, wherein the light column comprises a device according to any embodiment herein, in particular any one of embodiments 1 to 77.

[0582] Embodiment 79. A charged particle microscope system, the charged particle microscope system comprising:

[0583] a charged particle source configured to emit a charged particle beam; and

[0584] a light column configured to direct the charged particle beam toward a sample,

[0585] Wherein the optical column comprises a multipole objective lens comprising a plurality of objective multipole elements, and wherein the optical column is configured to at least partially correct a spherical aberration of the charged particle beam.

[0586] Embodiment 80. According to any embodiment of the present invention, in particular the charged particle microscope system described in Embodiment 79, the charged particle microscope system also includes a multipole condenser, and the multipole condenser includes one or more condenser quadrupole generating elements.

[0587] Embodiment 81. A charged particle microscope system according to any embodiment herein, in particular embodiment 80, wherein the one or more condenser quadrupole generating elements comprise:

[0588] A first concentrator quadrupole generating element, wherein the first concentrator quadrupole generating element is configured

[0589] to generate a first concentrator quadrupole field; and

[0590] A second concentrator quadrupole production element is positioned downstream of the first concentrator quadrupole production element and is configured to produce a second concentrator quadrupole field.

[0591] Embodiment 82. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 81 to 82, wherein the multipole condenser is positioned upstream of the multipole objective.

[0592] Embodiment 83. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 82, wherein the plurality of objective multipole elements comprises:

[0593] at least three quadrupole generating elements; and

[0594] At least three octupole generating elements.

[0595] Embodiment 84. A charged particle microscope system according to any embodiment herein, in particular Embodiment 83, wherein the octopole generating element is configured to at least partially correct the spherical aberration of the charged particle beam.

[0596] Embodiment 85. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 84, wherein each of the plurality of objective multipole elements is characterized by a multipole element inner diameter, the multipole element inner diameter representing the maximum diameter of the charged particle beam passing through the multipole element, and wherein the multipole element inner diameter of each objective multipole element is at most 5 millimeters (mm).

[0597] Embodiment 86. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 85, wherein the charged particle source is configured to emit the charged particle beam having an acceleration voltage, the acceleration voltage being one or more of at least 200 volts (V), at least 1,000V, at least 5,000V, at least 10,000V, at least 20,000V, at least 50,000V, at most 100,000V, at most 30,000V, at most 15,000V, at most 7,000V, at most 2,000V or at most 500V.

[0598] Embodiment 87. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 86, wherein the light column is configured so that the charged particle beam lacks an intersection at an intermediate point between the multipole condenser and the multipole objective.

[0599] Embodiment 88. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 87, wherein the charged particle beam comprises a linear combination of a first elementary ray component and a second elementary ray component, the first elementary ray component being measured along a first direction perpendicular to an axis of a light column along which the charged particle beam travels through the light column, the second elementary ray component being measured along a second direction perpendicular to the axis of the light column and each of the first directions, and wherein the charged particle microscope system is configured such that for a portion of the charged particle beam extending through the multipole objective, the magnitude of the first elementary ray component is equal to or greater than the magnitude of the second elementary ray component.

[0600] Embodiment 89. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 88, wherein the light column is configured so that the charged particle beam enters the multipole objective with a non-circular beam profile.

[0601] Embodiment 90. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 89, wherein the light column is configured so that the charged particle beam leaves the multipole objective with a non-circular beam profile.

[0602] Embodiment 91. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 90, wherein the plurality of objective multipole elements comprises exactly three quadrupole generating elements.

[0603] Embodiment 92. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 91, wherein exactly three objective multipole elements of the plurality of objective multipole elements are configured to generate a quadrupole field component.

[0604] Embodiment 93. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 92, wherein at least one objective multipole element of the plurality of objective multipole elements comprises an electrode formed as a microelectromechanical system (MEMS).

[0605] Embodiment 94. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 93, wherein the plurality of objective multipole elements comprises:

[0606] a first objective lens multipole element, the first objective lens multipole element being configured to generate a first objective

[0607] mirror multipole field;

[0608] A second objective lens multipole element, wherein the second objective lens multipole element is positioned at the first objective lens

[0609] downstream of the multipole element and configured to produce a second objective multipole field; and

[0610] A third objective multipole element is positioned downstream of the second objective multipole element and is configured to generate a third objective multipole field.

[0611] Embodiment 95. A charged particle microscope system according to any embodiment herein, in particular Embodiment 94, wherein the first objective multipole field comprises a first objective quadrupole field component and a first objective octopole field component, wherein the second objective multipole field comprises a second objective quadrupole field component and a second objective octopole field component, and wherein the third objective multipole field comprises a third objective quadrupole field component and a third objective octopole field component.

[0612] Embodiment 96. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 94 to 95, wherein one or more of the first objective multipole element, the second objective multipole element or the third objective multipole element comprises four electrodes shaped to generate an octopole field and a quadrupole field.

[0613] Embodiment 97. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 94 to 96, wherein the third objective lens multipole element comprises eight electrodes.

[0614] Embodiment 98. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 94 to 97, wherein one or more of the first objective lens multipole element, the second objective lens multipole element or the third objective lens multipole element comprises electrodes formed as a microelectromechanical system (MEMS).

[0615] Embodiment 99. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 94 to 98, wherein the plurality of objective multipole elements further include a fourth objective multipole element positioned downstream of the third objective multipole element and configured to generate a fourth objective multipole field, wherein the first objective multipole field includes a first objective quadrupole field component and a first objective octupole field component, wherein the second objective multipole field includes a second objective octupole field component, wherein the third objective multipole field includes a third objective quadrupole field component and a third objective octupole field component, and wherein the fourth objective multipole field includes a fourth objective quadrupole field component.

[0616] Embodiment 100. A charged particle microscope system according to any embodiment herein, in particular Embodiment 99, wherein the fourth objective lens multipole element comprises eight electrodes.

[0617] Embodiment 101. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 100, wherein the light column further comprises a chromatic aberration corrector positioned between the multipole condenser and the multipole objective.

[0618] Embodiment 102. A charged particle microscope system according to any embodiment herein, in particular embodiment 101, wherein the chromatic aberration corrector comprises a device according to any embodiment herein, in particular any one of embodiments 1 to 77.

[0619] Embodiment 103. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 79 to 102, wherein the charged particle beam is a first charged particle beam, and wherein the charged particle microscope is further configured to emit a second charged particle beam toward the sample.

[0620] Embodiment 104. A charged particle microscope system according to any embodiment herein, in particular Embodiment 103, wherein the charged particle microscope is configured so that the first charged particle beam and the second charged particle beam approach the sample along non-parallel directions.

[0621] Embodiment 105. A charged particle microscope system according to any embodiment herein, in particular any one of Embodiments 103 to 104, wherein when the second charged particle beam approaches the sample, the second charged particle beam has a conical beam profile, and wherein when the first charged particle beam approaches the sample, the first charged particle beam has a tapered non-circular beam profile.

[0622] Embodiment 106. A multipole component, the multipole component comprising:

[0623] a plurality of electrodes defining a central aperture therebetween, the central aperture extending at least partially along the beam axis,

[0624] wherein each electrode of the plurality of electrodes comprises a corresponding electrode active surface facing the central hole, wherein the plurality of electrodes comprises a first shape electrode subset and a second shape electrode subset, wherein the electrode active surface of each electrode in the first shape electrode subset has a first active surface shape as observed along a direction parallel to the beam axis, and wherein the electrode active surface of each electrode in the second shape electrode subset has a second active surface shape different from the first active surface shape as observed along a direction parallel to the beam axis.

[0625] Embodiment 107. A multipole element according to any embodiment herein, in particular embodiment 106, wherein the plurality of electrodes extend away from the central hole so that the multipole element has a first dimension as measured along a first direction perpendicular to the beam axis, and the first dimension is smaller than a second dimension of the multipole element as measured along a second direction perpendicular to the beam axis and each of the first directions.

[0626] Embodiment 108. A multipole element according to any embodiment herein, in particular embodiment 107, wherein the ratio of the second dimension to the first dimension is one or more of at least 1.2:1, at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at most 4:1, at most 2.7:1, at most 2.3:1, at most 1.7:1 or at most 1.3:1.

[0627] Embodiment 109. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 108, wherein a plurality of electrodes extend away from the central hole along a plane at least substantially perpendicular to the beam axis.

[0628] Embodiment 110. A multipolar element according to any embodiment herein, in particular any one of embodiments 106 to 109, wherein each electrode of the plurality of electrodes comprises a respective electrode extension extending away from the respective electrode active surface and configured to supply voltage to the respective electrode active surface, wherein the plurality of electrodes comprises a first side electrode subset and a second side electrode subset, wherein for each electrode in the first side electrode subset, the electrode extension extends away from the electrode active surface along a first lateral direction, and wherein for each electrode in the second side electrode subset, the electrode extension extends away from the electrode active surface along a second lateral direction opposite to the first lateral direction.

[0629] Embodiment 111. A multipolar element according to any embodiment herein, in particular embodiment 110, wherein, for each electrode of the plurality of electrodes, the electrode extension comprises an electrical contact location configured to couple to an electrical lead to supply the voltage to the electrode active surface.

[0630] Embodiment 112. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 111, wherein the plurality of electrodes extend away from the central hole partially along a radial direction perpendicular to the beam axis and partially along an axial direction parallel to the beam axis.

[0631] Embodiment 113. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 112, wherein the multipole element extends along a direction parallel to the beam axis between a proximal end region adjacent to the central hole and a distal end region away from the central hole, wherein the multipole element has:

[0632] a first diameter at the proximal end region along a line perpendicular to the

[0633] Measurement of the direction of the beam axis; and

[0634] a second diameter, the second diameter being measured at the distal end region in a direction perpendicular to the beam axis, and

[0635] Wherein the first diameter is smaller than the second diameter.

[0636] Embodiment 114. A multipole element according to any embodiment herein, in particular Embodiment 113, wherein the ratio of the second diameter to the first diameter is one or more of at least 1.2:1, at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at most 4:1, at most 2.7:1, at most 2.3:1, at most 1.7:1 or at most 1.3:1.

[0637] Embodiment 115. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 114, wherein each electrode of the plurality of electrodes comprises a corresponding electrode extension, wherein the corresponding electrode extension extends away from the corresponding electrode active surface and is configured to supply voltage to the corresponding electrode active surface, and wherein, for each electrode, the electrode extension extends away from the electrode active surface in a direction that is angled relative to each of a radial direction perpendicular to the beam axis and an axial direction parallel to the beam axis.

[0638] Embodiment 116. A multipolar element according to any embodiment herein, in particular embodiment 115, wherein, for each electrode of the plurality of electrodes, the electrode extension comprises an electrical contact location configured to couple to an electrical lead to supply the voltage to the electrode active surface.

[0639] Embodiment 117. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 116, wherein the multipole element is configured to generate one or more of a quadrupole electrostatic field, a hexapole electrostatic field, an octapole electrostatic field or a 12-pole electrostatic field within the central hole.

[0640] Embodiment 118. The multipolar element according to any embodiment herein, in particular any one of embodiments 106 to 117, wherein the plurality of electrodes consists of one of four electrodes, six electrodes, and eight electrodes.

[0641] Embodiment 119. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 118, wherein the plurality of electrodes comprises exactly four electrodes, and wherein the multipole element is configured to generate a quadrupole electrostatic field within the central hole.

[0642] Embodiment 120. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 118, wherein the plurality of electrodes comprises exactly eight electrodes, and wherein the multipole element is configured to generate a quadrupole electrostatic field within the central hole.

[0643] Embodiment 121. A multipole element according to any embodiment herein, in particular embodiment 120, wherein the multipole element is configured to generate the quadrupole electrostatic field with an accompanying parasitic 12-pole electrostatic field, so that the ratio of the 12-pole to quadrupole components characterizing the 12-pole electrostatic field and the quadrupole electrostatic field generated by the multipole element is one or more of at most 0.1, at most 0.05, at most 0.01 or at least 0.001.

[0644] Embodiment 122. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 118 and 120 to 121, wherein the plurality of electrodes comprises exactly eight electrodes, and wherein the multipole element is configured to generate an octopole electrostatic field within the central hole.

[0645] Embodiment 123. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 118, wherein the plurality of electrodes comprises exactly 16 electrodes, and wherein the multipole element is configured to generate an octopole electrostatic field within the central hole.

[0646] Embodiment 124. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 123, wherein each of the first shape electrode subset and the second shape electrode subset comprises an equal number of electrodes.

[0647] Embodiment 125. A multipole element according to any embodiment herein, in particular any one of embodiments 106 to 124, wherein the electrodes in the first shape electrode subset are circumferentially staggered with the electrodes in the second shape electrode subset.

[0648] Embodiment 126. A multipolar element according to any embodiment herein, in particular any one of embodiments 106 to 125, wherein the electrode active surface of each electrode in the first shape electrode subset is wider than the electrode active surface of each electrode in the second shape electrode subset.

[0649] Embodiment 127. A multipole component, the multipole component comprising:

[0650] A plurality of electrodes defining a central hole therebetween, the central hole at least partially

[0651] Particularly extending along the beam axis;

[0652] The plurality of electrodes extend away from the central hole partially along a radial direction perpendicular to the beam axis and partially along an axial direction parallel to the beam axis.

[0653] Embodiment 128. The multipole element according to any embodiment herein, in particular embodiment 127, wherein the multipole element extends along a direction parallel to the beam axis between a proximal end region adjacent to the central hole and a distal end region away from the central hole, wherein the multipole element has:

[0654] a first diameter at the proximal end region along a line perpendicular to the

[0655] Measurement of the direction of the beam axis; and

[0656] a second diameter, the second diameter being measured at the distal end region in a direction perpendicular to the beam axis, and

[0657] Wherein the first diameter is smaller than the second diameter.

[0658] Embodiment 129. A multipole element according to any embodiment herein, in particular Embodiment 128, wherein the ratio of the second diameter to the first diameter is one or more of at least 1.2:1, at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at most 4:1, at most 2.7:1, at most 2.3:1, at most 1.7:1 or at most 1.3:1.

[0659] Embodiment 130. The multipolar element according to any embodiment herein, in particular any one of embodiments 127 to 129, wherein each electrode of the plurality of electrodes comprises:

[0660] a corresponding electrode active surface, the corresponding electrode active surface facing the central hole; and

[0661] a respective electrode extension extending away from the respective electrode active surface and comprising an electrical contact location configured to couple to an electrical lead to supply a voltage to the respective electrode active surface, and

[0662] The electrode active surface of each electrode is offset from the electrical contact location along an axial direction parallel to the beam axis.

[0663] Embodiment 131. A multipole element according to any embodiment herein, in particular any one of embodiments 127 to 130, wherein the multipole element has:

[0664] A first dimension measured along a first direction perpendicular to the beam axis

[0665] and viewing along said beam axis; and

[0666] a second dimension measured along a second direction perpendicular to each of the beam axis and the first direction and viewed along the beam axis, and

[0667] The first size is smaller than the second size.

[0668] Embodiment 132. A multipole element according to any embodiment herein, in particular any one of embodiments 127 to 131, wherein the multipole element is configured to generate one or more of a quadrupole electrostatic field, a hexapole electrostatic field, an octapole electrostatic field or a 12-pole electrostatic field within the central hole.

[0669] Embodiment 133. A multipolar element according to any embodiment herein, in particular any one of embodiments 137 to 132, wherein the plurality of electrodes consists of one of four electrodes, six electrodes, and eight electrodes.

[0670] Embodiment 134. A multipole element according to any embodiment herein, in particular any one of embodiments 127 to 133, wherein the plurality of electrodes comprises exactly four electrodes, and wherein the multipole element is configured to generate a quadrupole electrostatic field within the central hole.

[0671] Embodiment 135. A multipole element according to any embodiment herein, in particular any one of embodiments 127 to 133, wherein the plurality of electrodes comprises exactly eight electrodes, and wherein the multipole element is configured to generate a quadrupole electrostatic field within the central hole.

[0672] Embodiment 136. A multipole element according to any embodiment herein, in particular Embodiment 135, wherein the multipole element is configured to generate the quadrupole electrostatic field with an accompanying parasitic 12-pole electrostatic field, such that the ratio of the 12-pole to quadrupole components characterizing the 12-pole electrostatic field and the quadrupole electrostatic field generated by the multipole element is one or more of at most 0.1, at most 0.05, at most 0.01 or at least 0.001.

[0673] Embodiment 137. A multipole element according to any embodiment herein, in particular any one of embodiments 127 to 133 and 136, wherein the plurality of electrodes comprises exactly eight electrodes, and wherein the multipole element is configured to generate an octopole electrostatic field within the central hole.

[0674] Embodiment 138. A multipole element according to any embodiment herein, in particular any one of embodiments 127 to 133, wherein the plurality of electrodes comprises exactly 16 electrodes, and wherein the multipole element is configured to generate an octopole electrostatic field within the central hole.

[0675] Embodiment 139. A multipole element according to any embodiment herein, in particular any one of embodiments 127 to 138, wherein each electrode of the plurality of electrodes comprises a corresponding electrode active surface facing the central hole, wherein the plurality of electrodes comprises a first shape electrode subset and a second shape electrode subset, wherein the electrode active surface of each electrode in the first shape electrode subset has a first active surface shape as observed along a direction parallel to the beam axis, and wherein the electrode active surface of each electrode in the second shape electrode subset has a second active surface shape different from the first active surface shape as observed along a direction parallel to the beam axis.

[0676] Embodiment 140. The multipole element according to any embodiment herein, in particular Embodiment 139, wherein each of the first shape electrode subset and the second shape electrode subset comprises an equal number of electrodes.

[0677] Embodiment 141. A multipole element according to any embodiment herein, in particular any one of embodiments 139 to 140, wherein the electrodes in the first shape electrode subset are circumferentially staggered with the electrodes in the second shape electrode subset.

[0678] Embodiment 142. A multipole component, the multipole component comprising:

[0679] a plurality of electrodes distributed around and defining the central aperture, wherein each electrode of the plurality of electrodes comprises:

[0680] a corresponding electrode active surface, the corresponding electrode active surface facing the central hole;

[0681] and

[0682] a respective electrode extension extending away from the respective electrode active surface and configured to supply a voltage to the respective electrode active surface, wherein the plurality of electrodes comprises a first side electrode subset and a second side electrode subset, wherein

[0683] For each electrode in the first side electrode subset, the electrode extension extends away from the electrode active surface along a first lateral direction, and for each electrode in the second side electrode subset, the electrode extension extends away from the electrode active surface along a second lateral direction opposite to the first lateral direction.

[0684] Embodiment 143. A multipole element according to any embodiment herein, in particular Embodiment 142, wherein the electrode extensions of the electrodes in the first side electrode subset extend into and terminate in a first side region of the multipole element, wherein the electrode extensions of the electrodes in the second side electrode subset extend into and terminate in a second side region of the multipole element, and wherein the first side region and the second side region are positioned on opposite sides of the center hole.

[0685] Embodiment 144. A multipolar element according to any embodiment herein, in particular any one of embodiments 142 to 143, wherein, for each electrode of the plurality of electrodes, the electrode extension comprises an electrical contact position configured to couple to an electrical lead to supply the voltage to the electrode active surface.

[0686] Embodiment 145 The multipole element according to any embodiment herein, in particular any one of embodiments 142 to 144, wherein the first lateral direction and the second lateral direction are at least substantially antiparallel to each other.

[0687] Embodiment 146. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 145, wherein the multipole element is configured to receive a charged particle beam traveling along a beam axis extending through the central hole, and wherein each of the first lateral direction and the second lateral direction is at least substantially perpendicular to the beam axis.

[0688] Embodiment 147. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 146, wherein the multipole element is configured to receive a charged particle beam traveling along a beam axis extending through the central hole, and wherein each of the first lateral direction and the second lateral direction is angled relative to each of a radial direction perpendicular to the beam axis and an axial direction parallel to the beam axis.

[0689] Embodiment 148. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 147, wherein the first lateral direction and the second lateral direction extend in opposite directions relative to the beam axis, and wherein the first lateral direction and the second lateral direction extend partially away from the center hole along an axial direction parallel to the beam axis.

[0690] Embodiment 149. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 148, wherein the plurality of electrodes extend away from the central hole so that the multipole element has a first dimension as measured along a first direction perpendicular to the beam axis, the first dimension being smaller than a second dimension of the multipole element as measured along a second direction perpendicular to the beam axis and each of the first directions.

[0691] Embodiment 150. A multipole element according to any embodiment herein, in particular Embodiment 149, wherein the ratio of the second dimension to the first dimension is one or more of at least 1.2:1, at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at most 4:1, at most 2.7:1, at most 2.3:1, at most 1.7:1 or at most 1.3:1.

[0692] Embodiment 151. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 150, wherein the multipole element is configured to generate one or more of a quadrupole electrostatic field, a hexapole electrostatic field, an octapole electrostatic field or a 12-pole electrostatic field within the central hole.

[0693] Embodiment 152. A multipolar element according to any embodiment herein, in particular any one of embodiments 142 to 151, wherein the plurality of electrodes consists of one of four electrodes, six electrodes, and eight electrodes.

[0694] Embodiment 153. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 152, wherein the plurality of electrodes comprises exactly four electrodes, and wherein the multipole element is configured to generate a quadrupole electrostatic field within the central hole.

[0695] Embodiment 154. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 152, wherein the plurality of electrodes comprises exactly eight electrodes, and wherein the multipole element is configured to generate a quadrupole electrostatic field within the central hole.

[0696] Embodiment 155. A multipole element according to any embodiment herein, in particular Embodiment 154, wherein the multipole element is configured to generate the quadrupole electrostatic field with an accompanying parasitic 12-pole electrostatic field, such that the ratio of the 12-pole to quadrupole components characterizing the 12-pole electrostatic field and the quadrupole electrostatic field generated by the multipole element is one or more of at most 0.1, at most 0.05, at most 0.01 or at least 0.001.

[0697] Embodiment 156. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 152 and 154 to 155, wherein the plurality of electrodes comprises exactly eight electrodes, and wherein the multipole element is configured to generate an octopole electrostatic field within the central hole.

[0698] Embodiment 157. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 152, wherein the plurality of electrodes comprises exactly 16 electrodes, and wherein the multipole element is configured to generate an octopole electrostatic field within the central hole.

[0699] Embodiment 158. A multipole element according to any embodiment herein, in particular any one of embodiments 142 to 157, wherein each electrode of the plurality of electrodes comprises a corresponding electrode active surface facing the central hole, wherein the plurality of electrodes comprises a first shape electrode subset and a second shape electrode subset, wherein the electrode active surface of each electrode in the first shape electrode subset has a first active surface shape as observed along a direction parallel to the beam axis, and wherein the electrode active surface of each electrode in the second shape electrode subset has a second active surface shape different from the first active surface shape as observed along a direction parallel to the beam axis.

[0700] Embodiment 159. The multipolar element according to any embodiment herein, in particular Embodiment 158, wherein each of the first shape electrode subset and the second shape electrode subset comprises an equal number of electrodes.

[0701] Embodiment 160. A multipole element according to any embodiment herein, in particular any one of embodiments 158 to 159, wherein the electrodes in the first shape electrode subset are circumferentially staggered with the electrodes in the second shape electrode subset.

[0702] Embodiment 161. A charged particle microscope system, the charged particle microscope system comprising:

[0703] a charged particle source configured to emit a charged particle beam; and

[0704] an optical column configured to direct the charged particle beam toward a sample;

[0705] Wherein the light column comprises a multipole element according to any embodiment herein, in particular any one of embodiments 106 to 160.

[0706] Embodiment 162. A charged particle microscope system according to any embodiment herein, in particular Embodiment 161, wherein the light column is configured to at least partially correct the spherical aberration of the charged particle beam.

[0707] Embodiment 163. A charged particle microscope system according to any embodiment herein, in particular any one of embodiments 161 to 162, wherein the light column comprises a multipole objective lens, and the multipole objective lens comprises a multipole element according to any embodiment herein, in particular any one of embodiments 106 to 160.

[0708] Embodiment 164. A multipole objective lens, comprising:

[0709] a plurality of multipole elements, the plurality of multipole elements being axially aligned with respect to the beam axis,

[0710] The plurality of multipole elements are configured to focus a charged particle beam to a target focusing position, wherein the plurality of multipole elements include a proximal multipole element, the proximal multipole element being adjacent to the target focusing position relative to the remaining multipole elements and separated from the target focusing position by a working distance, and wherein the plurality of multipole elements are completely contained within a first angular envelope, the first angular envelope being defined in a first plane containing the beam axis, the first angular envelope subtending a first angle of at most 50 degrees, and the working distance being at most 10 mm.

[0711] Embodiment 165. A multipole objective according to any embodiment herein, in particular Embodiment 164, wherein the plurality of multipole elements comprises at least three multipole elements, each multipole element being configured to generate each of a corresponding quadrupole electrostatic field and a corresponding octopole electrostatic field.

[0712] Embodiment 166. A multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 165, wherein the plurality of multipole elements comprises at least four multipole elements, wherein at least three of the plurality of multipole elements are configured to generate a corresponding quadrupole electrostatic field, and wherein at least three of the plurality of multipole elements are configured to generate a corresponding octopole electrostatic field.

[0713] Embodiment 167. A multipole objective according to any embodiment herein, in particular Embodiment 166, wherein at least two multipole elements of the plurality of multipole elements are configured to generate each of a corresponding quadrupole electrostatic field and a corresponding octopole electrostatic field.

[0714] Embodiment 168. A multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 167, wherein each pair of adjacent multipole elements among the plurality of multipole elements are separated by corresponding multipole element gaps, and the corresponding multipole element gaps are one or more of at least 0.2 mm, at least 0.5 mm, at least 1 mm, at most 1.5 mm, at most 0.7 mm or at most 0.3 mm.

[0715] Embodiment 169. A multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 168, wherein each of the plurality of multipole elements has a corresponding multipole element length as measured along a direction parallel to the beam axis, and the corresponding multipole element length is one or more of at least 2 mm, at least 5 mm, at least 10 mm, at most 15 mm, at most 10 mm, at most 7 mm or at most 3 mm.

[0716] Embodiment 170. A multipole objective according to any embodiment herein, in particular embodiment 169, wherein each of the plurality of multipole elements comprises a corresponding central region, wherein the corresponding central region defines a central hole through which the beam axis extends, and wherein the multipole element length of each multipole element is measured in its corresponding central region.

[0717] Embodiment 171. A multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 170, wherein the plurality of multipole elements include a distal multipole element distal to the target focusing position relative to the remaining multipole elements, and wherein the plurality of multipole elements have a stack length as measured along a direction parallel to the beam axis between the proximal multipole element and the distal multipole element, the stack length being one or more of at least 15 mm, at least 20 mm, at least 25 mm, at least 30 mm, at least 35 mm, at least 40 mm, at most 50 mm, at most 37 mm, at most 32 mm, at most 27 mm, at most 22 mm or at most 17 mm.

[0718] Embodiment 172. A multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 171, wherein the plurality of multipole elements are configured to operate as an objective to focus the charged particle beam to the target focusing position having a third-order spherical aberration of at most 1 mm.

[0719] Embodiment 173. A multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 172, wherein the plurality of multipole elements are completely contained within a second angular envelope, the second angular envelope is confined in a second plane containing the beam axis and perpendicular to the first plane, the second angular envelope subtends a second angle substantially equal to the first angle, and the working distance is at most 10 mm.

[0720] Embodiment 174. A multipole objective according to any embodiment herein, in particular Embodiment 173, wherein the second angle is at most 50 degrees.

[0721] Embodiment 175. According to any embodiment herein, in particular any one of embodiments 164 to 174, the multipole objective further comprises a lens housing surrounding the plurality of multipole elements, wherein a portion of the lens housing surrounding the plurality of multipole elements is conical or truncated-conical in shape.

[0722] Embodiment 176. A multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 175, wherein the plurality of multipole elements are completely contained within a second angular envelope, the second angular envelope is confined in a second plane containing the beam axis and perpendicular to the first plane, the second angular envelope subtends a second angle greater than the first angle, and the working distance is at most 10 mm.

[0723] Embodiment 177. According to any embodiment herein, in particular any one of embodiments 164 to 176, the multipole objective further comprises a lens housing surrounding the plurality of multipole elements, wherein a portion of the lens housing surrounding the plurality of multipole elements has a larger angular range in a second surface containing the beam axis and perpendicular to the first surface than in the first surface.

[0724] Embodiment 178. A device comprising:

[0725] a charged particle source configured to emit a charged particle beam; and

[0726] A light column configured to direct the charged particle beam at least partially along a beam

[0727] axis and directed toward a target focus position;

[0728] Wherein the light column comprises a multipole objective according to any embodiment herein, in particular any one of embodiments 164 to 177.

[0729] Embodiment 179. A device according to any embodiment herein, in particular Embodiment 178, wherein the charged particle beam is a first charged particle beam, wherein the beam axis is a first beam axis, wherein the device is configured to guide a second charged particle beam at least partially along the second beam axis and toward the target focusing position, wherein the second charged particle beam extends within an exclusion zone, and wherein the multipole objective is positioned completely outside the exclusion zone.

[0730] Embodiment 180. The device according to any embodiment herein, in particular embodiment 179, wherein the exclusion zone comprises a conical area.

[0731] Embodiment 181. A device according to any embodiment herein, in particular any one of embodiments 179 to 180, wherein the second charged particle beam at least partially defines the exclusion zone.

[0732] Embodiment 182. A device according to any embodiment herein, in particular any one of embodiments 179 to 181, wherein the light column is a first light column, wherein the device further comprises a second light column, the second light column being configured to direct the second charged particle beam toward the target focusing position, and wherein the second light column at least partially defines the exclusion zone.

[0733] Embodiment 183. A device according to any embodiment herein, in particular any one of embodiments 179 to 182, wherein the target focus position corresponds to a position on the sample, and wherein the sample partially defines the exclusion zone.

[0734] Embodiment 184. A device according to any embodiment herein, in particular any one of embodiments 179 to 183, wherein the exclusion zone at least partially defines the first angular envelope.

[0735] Embodiment 185. A device according to any embodiment herein, in particular any one of embodiments 179 to 184, wherein the first angular envelope represents an area completely outside the exclusion zone.

[0736] Embodiment 186. A device according to any embodiment herein, in particular any one of embodiments 179 to 185, wherein the first charged particle beam is a focused ion beam, and wherein the second charged particle beam is an electron beam.

[0737] Embodiment 187. A method of assembling and / or operating a device according to any embodiment herein, in particular any one of embodiments 1 to 77 or embodiments 178 to 186.

[0738] Embodiment 188. A method of assembling and / or operating a charged particle microscope system according to any embodiment herein, in particular any one of Embodiments 78 to 105 or Embodiments 161 to 163.

[0739] Embodiment 189. A method of assembling and / or operating a multipole element according to any embodiment herein, in particular any one of embodiments 106 to 160 or embodiments 164 to 177.

[0740] In view of the many possible embodiments to which the principles of the disclosed technology can be applied, it should be recognized that the illustrated embodiments are only preferred embodiments and should not be considered as limiting the scope. Instead, the scope of the disclosed technology is defined by the following claims. Therefore, we claim protection for all that falls within the scope of these claims.

Claims

1. A device, comprising: a charged particle source configured to emit a charged particle beam; and a light column configured to direct the charged particle beam toward a sample, The light column comprises: a multipole concentrator comprising one or more concentrator quadrupole generating elements; and A multipole objective lens, comprising a plurality of objective lens multipole elements, Wherein the plurality of objective lens multipole elements comprises: at least three quadrupole generating elements; and At least three octupole generating elements, Wherein the octopole generating element of the multipole objective is configured to at least partially correct a spherical aberration of the charged particle beam.

2. The apparatus of claim 1, wherein the one or more concentrator quadrupole generating elements comprise: a first concentrator quadrupole generating element configured to generate a first concentrator quadrupole field; and A second concentrator quadrupole production element is positioned downstream of the first concentrator quadrupole production element and is configured to produce a second concentrator quadrupole field. 3 . The apparatus of claim 1 , wherein the charged particle source is configured to emit the charged particle beam having an acceleration voltage of at most 100,000 volts (V).

4. The apparatus of claim 1, wherein the optical column is configured such that the charged particle beam lacks an intermediate point intersection between the multipole condenser and the multipole objective.

5. The apparatus of claim 1, wherein the plurality of objective lens multipole elements comprises exactly three quadrupole generating elements.

6. The apparatus of claim 1, wherein one or more of the objective multipole elements comprise four electrodes shaped to generate an octopole field and a quadrupole field.

7. The apparatus of claim 1, wherein the plurality of objective lens multipole elements comprises: a first objective multipole element, the first objective multipole element being configured to generate a first objective multipole field including a first objective quadrupole field component and a first objective octopole field component; a second objective multipole element positioned downstream of the first objective multipole element and configured to generate a second objective multipole field including a second objective quadrupole field component and a second objective octopole field component; and A third objective multipole element is positioned downstream of the second objective multipole element and is configured to generate a third objective multipole field including a third objective quadrupole field component and a third objective octupole field component.

8. The apparatus of claim 1, wherein the plurality of objective lens multipole elements comprises: a first objective multipole element, the first objective multipole element being configured to generate a first objective multipole field including a first objective quadrupole field component and a first objective octopole field component; a second objective multipole element positioned downstream of the first objective multipole element and configured to generate a second objective multipole field including a second objective octopole field component; a third objective multipole element positioned downstream of the second objective multipole element and configured to generate a third objective multipole field including a third objective quadrupole field component and a third objective octopole field component; and A fourth objective multipole element is positioned downstream of the third objective multipole element and is configured to generate a fourth objective multipole field including a fourth objective quadrupole field component.

9. The apparatus of claim 8, wherein the fourth objective multipole element comprises eight electrodes.

10. The apparatus of claim 1, wherein the optical column further comprises a chromatic aberration corrector positioned between the multipole condenser and the multipole objective.

11. A device, comprising: a charged particle source configured to emit a charged particle beam; and a light column configured to direct the charged particle beam toward a sample, The light column comprises a multipole objective lens, and the multipole objective lens comprises a plurality of objective lens multipole elements. Wherein the plurality of objective lens multipole elements comprises: at least three quadrupole generating elements; and At least three octupole generating elements, wherein the optical column is configured such that the charged particle beam enters the multipole objective with a non-circular beam profile, and wherein the octopole generating element of the multipole objective is configured to at least partially correct a spherical aberration of the charged particle beam.

12. The device of claim 11, further comprising a multipolar concentrator comprising one or more quadrupole generating elements.

13. An apparatus according to claim 11, wherein the charged particle beam comprises a linear combination of a first elementary ray component and a second elementary ray component, the first elementary ray component being measured along a first direction perpendicular to an axis of an optical column along which the charged particle beam travels through the optical column, and the second elementary ray component being measured along a second direction perpendicular to each of the axis of the optical column and the first direction, and wherein the apparatus is configured such that for a portion of the charged particle beam extending through the multipole objective, the magnitude of the first elementary ray component is equal to or greater than the magnitude of the second elementary ray component.

14. The apparatus of claim 11, wherein the plurality of objective lens multipole elements comprises: a first objective multipole element, the first objective multipole element being configured to generate a first objective multipole field including a first objective quadrupole field component and a first objective octopole field component; a second objective multipole element positioned downstream of the first objective multipole element and configured to generate a second objective multipole field including a second objective quadrupole field component and a second objective octopole field component; and A third objective multipole element is positioned downstream of the second objective multipole element and is configured to generate a third objective multipole field including a third objective quadrupole field component and a third objective octupole field component.

15. The apparatus of claim 11, wherein the plurality of objective lens multipole elements comprises: a first objective multipole element, the first objective multipole element being configured to generate a first objective multipole field including a first objective quadrupole field component and a first objective octopole field component; a second objective multipole element positioned downstream of the first objective multipole element and configured to generate a second objective multipole field including a second objective octopole field component; a third objective multipole element positioned downstream of the second objective multipole element and configured to generate a third objective multipole field including a third objective quadrupole field component and a third objective octopole field component; and A fourth objective multipole element is positioned downstream of the third objective multipole element and is configured to generate a fourth objective multipole field including a fourth objective quadrupole field component.

16. A device, comprising: a charged particle source configured to emit a charged particle beam; and an optical column configured to direct the charged particle beam toward a sample, wherein the optical column comprises: a multipole concentrator comprising one or more concentrator quadrupole generating elements; and A multipole objective lens, comprising a plurality of objective lens multipole elements, wherein the plurality of objective multipole elements comprises at least three quadrupole generating elements, wherein the optical column is configured such that the charged particle beam is characterized by a non-circular beam profile through at least a portion of the multipole objective, and wherein the optical column is configured to at least partially correct a spherical aberration of the charged particle beam.

17. The apparatus of claim 16, wherein the multipole objective further comprises at least three octopole generating elements configured to at least partially correct the spherical aberration of the charged particle beam.

18. An apparatus according to claim 16, wherein each of the plurality of objective multipole elements is characterized by a multipole element inner diameter, the multipole element inner diameter representing a maximum diameter of the charged particle beam passing through the objective multipole element, and wherein the multipole element inner diameter of each objective multipole element is at most 5 millimeters (mm).

19. The apparatus of claim 16, wherein at least one of the plurality of objective multipole elements comprises an electrode formed as a micro-electromechanical system (MEMS).

20. The device of claim 16, wherein the charged particle beam is a first charged particle beam, wherein the device is further configured to emit a second charged particle beam toward the sample, wherein when the second charged particle beam approaches the sample, the second charged particle beam has a conical beam profile, and wherein when the first charged particle beam approaches the sample, the first charged particle beam has a tapered non-circular beam profile.

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