Charged particle lens, electromagnetic lens and charged particle optical device

Abstract

To provide a charged particle lens which includes permanent magnets, nonetheless enables the optical characteristics of the charged particle lens to be highly accurately adjusted.SOLUTION: A finely-adjustable charged particle lens (10) comprises a magnetic circuit assembly (20) comprising permanent magnets (21) and a yoke body (25) and enclosing a beam passage (11) extending along a longitudinal axis (cx). The permanent magnets is arranged between an inner yoke element (250) and an outer yoke element (251) in such a manner that a magnetic circuit having at least two gaps (290, 291) generates a magnetic field (61) toward inward to reach the beam passage. An electromagnetic adjustment coil (31) is arranged between an inner yoke shell (250) and an outer yoke shell (251). The electromagnetic adjustment coil (31) is driven by adjustable support current mainly flowing along a circumferential direction, and modifies a magnetic flux of the magnetic circuit, causing a change in magnetic flux density in the gaps (290, 291).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims the benefit of Paris Convention priority of European Patent Application No. 22216094.7, filed December 22, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a charged particle lens including a permanent magnet configured to modify a charged particle beam of a charged particle optical device configured to be used for lithographic imaging and similar processing purposes, including nanopatterning. Such a lens comprises a passage for the charged particle beam along a longitudinal axis that corresponds to the direction of propagation of the charged particle beam itself and that will usually be aligned concentrically with the optical axis of the charged particle optical device in which it is used.

[0003] The invention further relates to electromagnetic lenses, including charged particle magnetic lenses, and to charged particle optical devices including lenses of the type described above. [Background technology]

[0004] The applicant has realized a charged particle multi-beam device that can incorporate one or more of the above types of lenses and has developed corresponding charged particle optical elements, pattern definition devices, and writing methods suitable for multiple charged particle beams simultaneously; a 50 keV electron multi-beam writer, called eMET (electron Mask Exposure Tool) or MBMW (multi-beam mask writer), has been commercialized and is used to realize any photomask for 193 nm immersion lithography, masks for EUV lithography, and templates for nanoimprint lithography. The applicant's system is also called PML2 (Projection Mask-Less Lithography), which is used for electron beam direct write (EBDW) applied directly to the substrate.

[0005] To increase throughput in industrial mass production, particularly for maskless lithography and direct substrate (e.g., wafer) writing, it is necessary to increase the current carried by the charged particle beam passing through the charged particle nanopatterning device; this usually comes at the expense of limited resolution due to Coulomb interactions between the charged particles, and requires corresponding compensation by reducing the magnitude of optical aberrations introduced by the device through other mechanisms. To this end, applicant has developed a charged particle multi-beam device comprising multiple parallel optical columns combined in a multi-column approach, where each column has a reduced ("slim") cross-sectional diameter compared to earlier writer configurations such as the eMET.

[0006] Such multi-column devices (an example of which is discussed below with reference to FIG. 14) allow significantly higher currents through the charged particle beam while overcoming the limitations imposed by the trade-off between current and optical aberrations found in single-column systems. This is due to the fact that the total current delivered to the target is split among multiple optical axes, while the resolution limit is governed by the amount of current per optical axis. Single columns of this type are well known in the prior art, such as in the applicant's US Pat. No. 6,768,125, EP 2 187 427 A1 (=US Pat. No. 8,222,621), and EP 2 363 875 A1 (=US Pat. No. 8,378,320). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US6,768,125 [Patent Document 2] EP2 187 427 A1 [Patent Document 3] US$8,222,621 [Patent Document 4] EP2 363 875 A1 [Patent Document 5] US$8,378,320 [Patent Document 6] US$9,165,745 Summary of the Invention [Problem to be solved by the invention]

[0008] A typical multi-column system includes multiple optical sub-columns, each of which includes an illumination system that delivers a wide, telecentric charged particle beam to a pattern definition system and then to charged particle projection optics, which may include, for example, multiple electrostatic, magnetic, and / or electromagnetic lenses.

[0009] To use such a system as a high-throughput direct-write wafer machine, it would be necessary to arrange a significant number of columns above a single semiconductor wafer, e.g., on the order of 100. However, this configuration limits the radial dimension of each column to a diameter that is only a fraction of the overall wafer width; for example, for a typical 300 mm (12 inch) wafer, a diameter of approximately 30 mm might be used. On the other hand, slim-diameter magnetic lenses cannot be realized with coil-type magnetic lenses because a reduction in column diameter would correspond to extremely large Joule heating due to the large currents required to drive the coils to generate sufficiently strong magnetic fields; however, there is insufficient space for an appropriate temperature control system, including high-precision sensors and isotropic uniform cooling, that would be required for a conventional coil-type magnetic lens.

[0010] While the above limitations imposed by thermal and geometrical (spatial) requirements are severe, they can be overcome by employing magnetic lenses based on permanent magnets in conjunction with a magnetically permeable yoke body to guide the magnetic flux and thus generate the magnetic field, as in one embodiment of the present invention. However, such permanent magnets are not highly tunable after fabrication and assembly, thus limiting their use in magnetic lenses. This represents a serious drawback compared to coil-based magnetic lenses, whose magnetic fields can be controlled by adjusting the current flowing through the coil. Magnet manufacturers' precision is crucial for the operational purposes of magnetic lenses incorporating such magnets, especially given the inherent limitations on the accuracy of the targeted magnetic field due to fabrication and assembly; current precision limits correspond to deviations of approximately 1% to 5% from the target field; field strengths are on the order of 1 T.

[0011] These deviations are due to manufacturing tolerances and statistical uncertainties, which are virtually unavoidable for a manufacturing process with reasonable yields of magnetic lenses for mass production. The present invention provides a new approach to compensating for these deviations by including additional components that allow tuning of the magnetic field during the initial setup and / or operation of the lens. The present invention removes the (unrealistic) precision constraints on the manufacture of permanent magnets for use in magnetic lenses and substantially increases the range of permanent magnet materials that can be used for high-precision systems, because Applicant's invention can compensate for deviations of actual permanent magnets from the desired nominal (rated) magnetic field strength, and can even tolerate larger deviations as long as the system's geometric parameters remain within specifications.

[0012] In situ, i.e., during operation of the device, tuning of permanent magnet-based charged particle lenses is typically performed by combining them with one or more additional electric lenses; i.e., by forming a charged particle electromagnetic lens, such as a combination of a permanent magnet-based magnetic lens and an electrostatic element for fine tuning. US 9,165,745 describes a permanent magnet-based electromagnetic lens combined with a coil-type magnetic lens for fine tuning. This allows tuning of the magnetic field, but at least suffers from the heating and geometrical (spatial) problems mentioned above. Furthermore, the magnetic field of the above-mentioned prior art magnetic lenses is insufficiently confined to the space of the charged particle lens itself, which causes serious cross-effects when multiple lenses are arranged side by side in a multi-column system.

[0013] In view of the above, it is an object of the present invention to provide a charged particle lens that includes permanent magnets but allows for precise adjustment of the optical properties of the lens. At the same time, it is desirable to increase the range of permanent magnets that can be used in this lens configuration. Furthermore, the lens of the present invention has a slim profile and allows for the confinement of magnetic and electric fields within the immediate vicinity of the lens itself; thus, enabling multi-column optical systems with reduced crosstalk. [Means for solving the problem]

[0014] Book Invention No. 1 From the perspective of configured to modify a charged particle beam of a charged particle optical system Charged particle lens and ,vinegar and a sleeve insert member. The charged particle lens has a passage space extending essentially along a longitudinal axis and allowing the passage of a charged particle beam, the charged particle lens including a magnetic circuit assembly, the magnetic circuit assembly including at least one permanent magnet, and Yoke body Includes; The yoke body is composed of at least two yoke elements, of which a first yoke element constitutes an inner yoke shell arranged to surround the passage space, and a second yoke element constitutes an outer yoke shell arranged to surround the inner yoke shell, the yoke elements being arranged circumferentially around the longitudinal axis and including a highly permeable material; the at least one permanent magnet is disposed between the at least two yoke elements and circumferentially surrounding the inner yoke shell, the at least one permanent magnet including a permanent magnetic material having two magnetic poles magnetically oriented toward the respective yoke elements; In the magnetic circuit assembly, the at least one permanent magnet and the yoke body are configured to guide magnetic flux density generated from the at least one permanent magnet through the yoke body, form a closed magnetic circuit across at least two gaps formed between respective (corresponding) axial faces of different yoke elements, and induce (generate) a magnetic field inwardly reaching the passage space within the gaps; the charged particle lens includes an electromagnetic conditioning coil disposed between the inner yoke shell and the outer yoke shell and configured to be driven by an adjustable supply current, the current in the electromagnetic conditioning coil flowing substantially along a circumferential direction around the longitudinal axis, the electromagnetic conditioning coil configured to modify the magnetic flux of the magnetic circuit to cause a change in magnetic flux density in at least one of the at least two gaps; The sleeve insert member is inserted into the passage space along the longitudinal axis, the sleeve insert member encloses a beam path extending along its longitudinal axis and having a radius smaller than the radius of the path space of the charged particle lens; the sleeve insert member includes a mounting body having an at least partially conductive portion and at least one conductive electrode element; the at least one conductive electrode element is configured to have an electric potential applied to it via a power source relative to a potential of the conductive portion of the mounting body to generate an electrostatic field within the beam passage; the electrode elements are configured to form a particle-optical lens in combination with a magnetic field within the beam path at one or more gaps; The charged particles Child The focal length of the lens is adjustable by modifying the electrical potential applied to the electrode elements. The present invention 2 From the perspective of , Book Inventive electromagnetic lens Z A charged particle optical device is provided that includes: The charged particle optical device is configured to affect a charged particle beam propagating along its longitudinal axis through a lens, the lens being part of a particle-optical system of the charged particle optical device. DETAILED DESCRIPTION OF THE INVENTION

[0015] ( form 1 ) The above-mentioned present invention 1 See perspective. (form 2 )form 1 In the electromagnetic lens described in It is preferable that the longitudinal axis of the sleeve insert member overlaps (coincides with) the longitudinal axis of the charged particle lens, the inner yoke shell extends along the longitudinal axis and circumferentially surrounds the sleeve insert member, at least two gaps in the magnetic circuit are positioned at either axial end of the inner yoke shell, each gap generates a defined magnetic field that extends radially inward and reaches into the passage space or beam passage, and the electrostatic field is generated by at least one of a plurality of electrode elements of the sleeve insert member that are configured to at least partially overlap with the magnetic field. (form 3 )form 1 In the electromagnetic lens described in Preferably, at least one of the plurality of electrode elements comprises an electrostatic multipole electrode including a plurality of sub-electrodes uniformly (evenly) arranged circumferentially around the longitudinal axis, the multipole electrode being connectable to a multi-channel power supply unit that provides an individual potential to each electrode. (form 4 )form 1 In the electromagnetic lens described in the electrode elements include beam aperture elements that define a limiting aperture having a defined radius about the longitudinal axis; the limiting aperture is configured to limit a lateral width of a charged particle beam propagating along the longitudinal axis; The beam aperture element is preferably connected to a current measuring device configured to measure the amount of charged particle beam absorbed in the beam aperture element. (form 5 ) The above-mentioned present invention 2 See perspective. (form 6 )form 5 In the charged particle optical apparatus described in the charged particle optical device is configured as a multi-column system including a plurality of particle optical columns; Each column is configured to use a respective particle beam and preferably includes a respective particle-optical system including a respective arrangement of charged particle lenses or electromagnetic lenses. (form 7 ) The method according to embodiment 1 electromagnetic In the lens, Preferably, the electromagnetic adjustment coil further comprises a sector-type electromagnetic adjustment coil structure including two or more sector coil elements, each configured with a respective radially oriented (inward or outward) general winding axis, and the sector coil elements of the sector-type electromagnetic adjustment coil are angularly offset circumferentially relative to each other around the longitudinal axis. (form 8 )form 7 Described in electromagnetic In the lens, The electromagnetic adjustment coil and the sector-type electromagnetic adjustment coil structure preferably have electrical interfaces to the exterior of the charged particle lens for supplying respective currents to the coil and coil elements, respectively. (form 9 ) The method according to embodiment 1 electromagnetic In the lens, The electromagnetic tuning coil preferably comprises an electrical interface to the exterior of the charged particle lens configured to supply current to the coil. (form 10 )form 8 Described in electromagnetic In the lens, The electrical interface preferably includes a passageway formed in the outer yoke shell. (form 11 ) The method according to embodiment 1 electromagnetic In the lens, Preferably, the electromagnetic adjustment coil, or both the electromagnetic adjustment coil and the sector-type electromagnetic adjustment coil structure provided therewith, are configured to cause a redistribution of magnetic flux between two or more branches of the magnetic circuit, causing a change in magnetic flux density in at least two gaps. (form 12 ) The method according to embodiment 1 electromagnetic In the lens, Preferably, the electromagnetic adjustment coil or both the electromagnetic adjustment coil and the sector-type electromagnetic adjustment coil structure provided therewith are configured to cause a modification of the magnetic flux that primarily affects one of two or more branches of the magnetic circuit, causing a change in the magnetic flux density in the corresponding gap. (form 13 ) The method according to embodiment 1 electromagnetic In the lens, Preferably, two or more electromagnetic adjustment coils are disposed at different locations associated with different components of the magnetic circuit assembly, configured to differentially adjust the magnetic fields in the two gaps. (form 14 ) The method according to embodiment 1 electromagnetic In the lens, It is preferable that the charged particle lens further includes a holder element configured to hold both the electromagnetic adjustment coil or the holder element (correctly, the electromagnetic adjustment coil) and the sector-type electromagnetic adjustment coil structure provided thereon at a predetermined position between the at least two yoke elements of the yoke body. (form 15 ) The method according to embodiment 1 electromagnetic In the lens, The second yoke element preferably forms a housing body for the charged particle lens, which encloses the other components of the magnetic circuit assembly, including all other yoke elements. (form 16 ) The method according to embodiment 1 electromagnetic In the lens, Preferably, the at least one permanent magnet has a magnetization that is substantially radially oriented. (form 17 ) The method according to embodiment 1 electromagnetic In the lens, The at least one permanent magnet is segmented according to two or more layers stacked along its longitudinal axis, and / or divided into two or more sectors arranged around its longitudinal axis, It is preferably made up of at least two sub-elements. (form 18 )form 17 Described in electromagnetic In the lens, Preferably, at least one temperature control device is disposed between each two of the plurality of sub-elements. (form 19 ) The method according to embodiment 1 electromagnetic In the lens, the charged particle lens having a generally rotationally symmetric shape along the longitudinal axis; A plurality of components of the magnetic circuit assembly, namely: the at least one permanent magnet, and the yoke body, and The electromagnetic adjustment coil is preferably arranged concentrically (coaxially) with said longitudinal axis and has a basic shape corresponding to that of a hollow cylinder or a hollow polygonal prism.

[0016] The above objects are achieved by a lens configured to modify (e.g., shape, focus / defocus, or otherwise manipulate) a charged particle beam of a charged particle optical device, the lens having a passage space (also referred to as a beam passage) extending primarily along a longitudinal axis and allowing passage of the charged particle beam, the lens further including a magnetic circuit assembly including at least one permanent magnet and a yoke body made of at least two components of high magnetic permeability, and an electromagnetic adjustment coil disposed in the yoke body.

[0017] The yoke body includes a first yoke element capable of constituting an inner yoke shell arranged to surround the passage space, and a second yoke element capable of constituting an outer yoke shell arranged to surround the inner yoke shell (here the terms "inner" and "outer" refer to their relative positions with respect to the central axis inside the lens assembly); these yoke elements are arranged circumferentially around the longitudinal axis and are preferably made from a highly permeable material such as a ferromagnetic substance or material.

[0018] At least one permanent magnet is disposed between at least two yoke elements, i.e., around the inner yoke shell and inside the outer yoke shell, and includes a permanent magnet material whose two magnetic poles are magnetically oriented mainly toward the respective yoke elements.

[0019] The permanent magnets and the yoke body form a closed magnetic circuit across at least two gaps that open into the beam passage and are formed between corresponding surfaces of the different yoke elements (e.g., at each axial end, between the surfaces of the inner yoke shell facing the corresponding surfaces of the outer yoke shell). The magnetic circuit thus guides the magnetic flux generated by the permanent magnets through the yoke body, inducing (generating) a magnetic field in the gaps that also reaches the beam passage. It is this magnetic field from the gaps that is used to form a magnetic lens for the charged particle beam propagating in the beam passage along the longitudinal axis. This magnetic lensing typically achieves a magnetic field accuracy within a range of 1% to 5% of the target value.

[0020] The electromagnetic adjustment coil, preferably disposed between the inner and outer yoke shells, is configured to be driven by an adjustable supply current; this current in the electromagnetic adjustment coil flows substantially circumferentially around the longitudinal axis, and the electromagnetic adjustment coil is configured to modify the magnetic flux in the magnetic circuit to cause a change in the magnetic flux density in at least one of a plurality of gaps used to form a magnetic lens in the beam path acting on the particle beam passing therethrough. Thus, the present invention allows for improved control of the particle lens characteristics with greater precision. The precision of such a lens can be within a range of 0.1% to 0.5% (or even better) of the desired magnetic field value due to modulation of the magnetic field in the gaps, or even smaller. This results in a magnetic lens that is produced with approximately an order of magnitude greater efficiency, i.e., closer to the designed optical characteristics, such as focal length, than the performance of the same magnetic lens without such an adjustment coil. The present invention also allows for controlling, e.g., modulating or stabilizing, the characteristics of the magnetic circuit during operation, depending on the actual situation.

[0021] In the technical solution underlying the present invention, the yoke elements and at least one permanent magnet together form a closed magnetic circuit with two gaps, but optionally also three or more gaps located next to the beam path; these gaps act as magnetic lenses, serving to guide a defined magnetic flux density and thus a magnetic field reaching the beam path. The electromagnetic adjustment coil of the present invention can also be used to compensate for deviations of the magnetic field from its nominal value. An electromagnetic adjustment coil of the present invention is positioned at an appropriate location to influence the magnetic flux in an appropriate manner. It can also be used to introduce and / or tune asymmetries in the magnetic circuit assembly. As a result, the present invention makes it possible to reduce or even eliminate deviations in strength and even in part in direction from the desired nominal value, thereby achieving specific characteristics according to the initial design that would otherwise not be compatible with the manufacturing process and inherent tolerances of the permanent magnet.

[0022] The present invention allows the use of currently manufactured permanent magnets that can be incorporated into charged particle lenses by adjusting the magnetic flux using the electromagnetic adjustment coils of the present invention. Therefore, the magnetic field that defines the lens effect at the gap can be fine-tuned. Therefore, the present invention allows the limited precision in the manufacturing of permanent magnet materials and components to be taken into account, and significantly helps to limit their effects. Furthermore, the present invention achieves a reduction in stray magnetic fields.

[0023] Furthermore, within the scope of the invention, any of the following developments, which can be combined where appropriate, are envisaged:

[0024] In one advantageous development of the invention, a sectorial electromagnetic adjustment coil structure can be provided, which includes two or more sector coil elements, each configured with a (general or overall) winding axis pointing in a respective radial direction (inward or outward). The sector coils of the sector adjustment coil are preferably arranged angularly offset circumferentially relative to one another around the longitudinal axis and are preferably configured to behave at least partially like a magnetic multipole.

[0025] Furthermore, the electromagnetic adjustment coil, and optionally the sector-type adjustment coil structure, may be suitably configured to cause a redistribution of magnetic flux between two or more branches of the magnetic circuit, causing a change in magnetic flux density in at least two gaps. This may be advantageous, for example, to reduce or increase the difference in focal length between two lenses. In combination with this, or alternatively, the electromagnetic adjustment coil, and optionally the sector-type adjustment coil structure, may be suitably configured to cause a modification of magnetic flux that primarily affects one of two or more branches of the magnetic circuit, causing a change in magnetic flux density in the corresponding gap. This allows single lenses to be fine-tuned with high precision to the requirements of the optical system.

[0026] Furthermore, it is often advantageous to provide two or more electromagnetic adjustment coils, which are further located at different locations associated with different components of the magnetic circuit assembly configured to adjust the magnetic fields in the two gaps differently. In this case and below, the electromagnetic adjustment coils may include or be configured as sector-type adjustment coil structures as deemed appropriate in each embodiment.

[0027] Furthermore, one yoke element can form a lens housing body that surrounds other parts of the magnetic circuit, in particular the other yoke element(s), as well as the permanent magnet(s) and electromagnetic adjustment coil(s). Generally, several parts of the magnetic circuit can be used to form the lens housing, at least one permanent magnet and / or at least one electromagnetic adjustment coil, all of which are arranged around the inner yoke shell, and / or all of the yoke elements can also be part of the lens housing body. The lens design can preferably have an overall rotationally symmetric shape about the longitudinal axis, with the components of the magnetic circuit assembly, in particular the permanent magnet(s), yoke body, and electromagnetic adjustment coil, being arranged coaxially with the longitudinal axis and preferably having a basic shape corresponding to a hollow cylinder or hollow polygonal prism.

[0028] A suitable holder may be provided inside the yoke body to hold the electromagnetic adjustment coil(s) in their / their respective defined positions. In particular, holder elements may be provided that are configured to maintain the electromagnetic adjustment coil(s) in their respective defined positions between at least two elements of the yoke body, which may be configured to precisely define the relative influence on each component of the magnetic circuit assembly.

[0029] Advantageously, the electromagnetic adjustment coil(s) of the present invention may be provided with an electrical interface to the exterior of the charged particle lens configured to supply current to the coil(s), the electrical interface preferably comprising a passageway such as a suitable hole formed in the outer yoke shell.

[0030] Additionally, there can be two or more electromagnetic tuning coils located at different locations associated with different components of the magnetic circuit or magnetic circuit assembly, which can be used to separately and precisely fine-tune single lenses.

[0031] Furthermore, the permanent magnets and / or one or more electromagnetic adjustment coils and / or their component(s) can be composite, e.g., composed of one or more sectors arranged around the longitudinal axis and / or segmented into two or more layers stacked along the longitudinal axis. These subelements (sectors, segments, and / or layers) can also be made of varying materials with different magnetic properties (permeability, geometric dimensions, etc.) to form local gradients of magnetic flux reduction. Thus, a tuning coil of the present invention can include two or more subelements, preferably formed as sectors of a ring-shaped element. This can be configured to form an azimuthal magnetic gradient, allowing the magnetic lens to have different azimuthal (azimuthally) varying magnetic flux densities around the longitudinal axis, and thus, an azimuthal varying magnetic field. The composite coil element can operate at least partially like a magnetic multipole. These sub-elements may further comprise individual electrical interfaces to the exterior of the charged particle lens, configured to supply respective electrical currents, for example via through holes formed in the outer yoke shell.

[0032] In many typical configurations, the permanent magnet(s) can have a magnetization that is substantially radially oriented. The term "substantially radially" is used herein to include cases where the orientation is "operationally radial," such that magnetic flux through the permanent magnet or electromagnetic element to the yoke elements flows in a generally radial direction (from the inner yoke element to the outer yoke element, or vice versa). (That is, "substantially" and "operationally" are meant to include not only a literal "radial" direction, as shown, for example, in FIGS. 8A, 8B, and 8D, but also directions that deviate somewhat from the literal radial direction, such as a direction parallel to the central angle bisector of the circular arc shown, for example, in FIG. 8C.)

[0033] In an advantageous development, the permanent magnet(s) may be composed of two or more layers stacked along the longitudinal axis; it may furthermore be appropriate to configure the permanent magnet(s) assembled from three or more sectors arranged circumferentially around the longitudinal axis, in which case the magnet sector(s) are preferably substantially wedge-shaped elements forming the sector(s) relative to the longitudinal axis.

[0034] The above object is also achieved by an electromagnetic lens including a charged particle lens according to the present invention and a sleeve insert member inserted into the beam passage (passage space) along a longitudinal axis. The sleeve insert member surrounds a smaller portion of the beam passage aperture but extends along the longitudinal axis between its ends; preferably, it at least overlaps the gaps of the yoke elements. The sleeve insert member includes one or more conductive electrode elements to which a respective electric potential can be applied using a power supply to generate an electric field within the beam passage. Advantageously, the electrode elements can be configured to form a particle-optical lens in combination with the magnetic field inside the passage aperture at the gap(s), in which case the optical parameters of the particle-optical lens, such as the focal length, can be further adjusted by modifying the electric potential applied to the electrode elements.

[0035] According to one suitable geometrical layout, the yoke body can extend between and thus form the two axial ends of the beam passage; in particular, a first element, e.g., an inner yoke shell, can extend from the beginning to the end of the central portion of the (beam) passage while surrounding a second element, e.g., the inner yoke shell, in the radial and axial directions, preferably maintaining an open gap at each end toward the outer yoke shell, which extends to each side of the second element. The yoke elements can thus form a geometric structure of two concentrically nested hollow cylinders. The inner yoke shell thus surrounds at least portions of the sleeve insert member; the gaps of the magnetic circuit each induce a magnetic field that reaches inward into the passage bore and overlaps with the electric fields generated by the electrode elements of the sleeve insert member, thereby establishing an electromagnetic lens. Such electromagnetic ultra-fine lenses can have high precision, with a precision range of as little as 1 ppm to 5 ppm for the designed characteristic. For example, the focal length of such electromagnetic lens(es) can be adjusted during operation, i.e., during the passage of a charged particle beam, by modifying the electrical potential applied to the electrode elements.

[0036] In many configurations, the sleeve insert member may include a ceramic body on which electrode elements are configured and disposed as conductive coatings each having a limited shape and area.

[0037] The electrode elements can often be configured (mechanically and electrically) to form at least one simple lens (Einzel lens); furthermore, in many forms of the invention, at least one of the electrode elements can comprise an electrostatic multipole electrode including a plurality of sub-electrodes uniformly (uniformly) arranged circumferentially around a longitudinal axis, allowing the lens to deflect or shape a charged particle beam traversing the electrode element, in which case the electrical potential applied to the sub-electrodes of this element can be defined to form a multipole electric field.

[0038] In many embodiments of the lens of the present invention, particularly when the lens is intended for use in conjunction with a pattern definition system (PD), a beam aperture element can be provided between the electrode elements, forming a limiting aperture having a defined radius about the longitudinal axis, which limits the lateral width of the charged particle beam propagating through the passageway. This limiting aperture can be used as a calibration aperture, capable of collecting particles, including those intentionally deflected in the pattern definition system; it is intended to prevent particles from reaching the charged particle beam target. Furthermore, for example, the beam aperture element can be connected to a current measuring device that can be used to measure the amount of charged particles (beam) absorbed in the beam aperture element. It is advantageous to have an electrostatic multipole electrode in front of, or upstream of, such a beam aperture element, configured to determine the lateral position of the beam relative to the longitudinal axis by applying different appropriate electrostatic potentials to sub-electrodes, thereby scanning the aperture with the beam.

[0039] Preferably, the charged particle lens can have a shape that is rotationally symmetrical overall along a longitudinal axis, in which case the components of the magnetic circuit assembly are arranged coaxially with respect to the longitudinal axis and preferably have a basic shape corresponding to a hollow cylinder or hollow polygonal prism.

[0040] Unlike known magnetic lenses, such as that shown in U.S. Pat. No. 9,165,745, the electromagnetic lens of the present invention has a completely closed magnetic loop, with only a number of "air gaps" in the housing body, which allows for the formation of a magnetic field in a desired region of the optical axis, thus minimizing the effects of stray magnetic fields (present in single-gap systems that obey Ampere's circuit law) that adversely affect the performance of electromagnetic lenses such as those employed in charged particle multi-beam nanopatterning devices. Therefore, providing (at least) two gaps is highly advantageous in order to minimize the stray magnetic fields present in the systems of the prior art described above. It will be apparent, however, that the number of gaps may be greater, such as three, four, five, or more, depending on the particular application of the lens.

[0041] For at least the above reasons, the present invention and its application in writer tools such as multi-column, multi-beam charged particle nanopatterning systems (e.g., for direct writing of substrates) provides a unique combination of magnetic, electrical, and calibration elements that is expected to have a significant impact on the development of high-throughput industrial processes for integrated circuits. The present invention greatly facilitates the layout, construction, fine-tuning, and even ultra-fine tuning of writer tools, particularly multi-column, multi-beam, mask-based writers.

[0042] The above object is also achieved by a charged particle optical device comprising a charged particle lens according to the invention (including an electromagnetic lens according to the invention) configured to influence a charged particle beam of the device propagating through the lens along its optical axis, the lens being part of a particle-optical system of the device that is preferred for magnetic lenses. In particular, the device can preferably be configured as a multi-column system comprising a plurality of charged particle optical columns, each column using a respective particle beam and comprising a respective optical system with a respective lens according to the invention.

[0043] In the following, exemplary and non-limiting embodiments (or examples) will be discussed, which are schematically illustrated in the drawings, in order to further explain the present invention. [Brief explanation of the drawings]

[0044] [Figure 1] An example of a charged particle lens according to a first embodiment of the present invention. Figure 1(A) (on the left side of the page) is a longitudinal cross-section of a charged particle lens including an example electromagnetic tuning coil according to the present invention, positioned at the "equator" position in the magnetic circuit. Figure 1(B) is a plot of the strength (magnitude) of the axial component of the magnetic field measured at the central axis as a function of the ordinate in Figure 1(A) with (dotted line) and without (solid line) the electromagnetic tuning coil. [Figure 2] An embodiment of a symmetrical ring-shaped electromagnetic tuning coil configured to control the magnetic lens of Figure 1(A). Figure 2(A) shows a partial cutaway view of the component, and Figure 2(B) shows a (longitudinal) cross section. [Figure 3] FIG. 2 is a top view of one embodiment of a sector-type electromagnetic tuning coil. [Figure 4] FIG. 1 is a perspective view of two coils as components of a four-sector structure of an example of a sector-type coil structure. [Figure 5] FIG. 1 is a plan view of a four-sector structure as an example of a sector coil structure. [Figure 6] 6A and 6B show an example of a charged particle lens according to another embodiment of the present invention, with an example of an asymmetrically positioned adjustment coil with respect to the ordinate of the lens. (A) shows a longitudinal cross section of the charged particle lens. (B) shows a plot of the strength (magnitude) of the axial component of the magnetic field measured at the central axis as a function of the ordinate in FIG. 6A, with (dashed line) and without (dotted line) the asymmetric adjustment coil. [Figure 7] 7A and 7B are perspective and longitudinal cross-sectional views, respectively, of a permanent magnet constructed from multiple ring elements with radial magnetization. [Figure 8]Respective cross-sectional views of several embodiments of permanent magnets (FIGS. 8(A)-8(D)), some of which are sectored (FIGS. 8(B)-8(D)), with preferred magnetization variations. [Figure 9]

[0033] Figure 9(A) shows a longitudinal cross-section of a charged particle lens and an internal electrical sleeve insert that form an example of an electrostatic lens system, according to a further embodiment of the present invention, the sleeve insert including multiple implementations of the electromagnetic tuning coils of the present invention. Figure 9(B) shows a plot of the strength (magnitude) of the axial components of the magnetic field (solid line) and electric field (dashed line) of the magnetic lens, measured at the central axis, as a function of the ordinate in Figure 9(A). [Figure 10] 9(B) is a schematic view of an example of a voltage supply connected to a sleeve insert member and its components in one embodiment of the lens of FIG. 9(A). [Figure 11] FIG. 1 is a cross-sectional view of an example of a multipole electrode having eight sub-electrodes. [Figure 12] FIG. 10 is an enlarged detailed view of the calibration aperture and preceding multipoles as components of the sleeve insert member of the exemplary electromagnetic lens of an embodiment of the present invention. [Figure 13] FIG. 1 is a longitudinal cross-sectional view of an example slim column writer tool incorporating an example charged particle lens of the present invention. [Figure 14] An example of a multi-column writer tool incorporating multiple embodiments of the lenses of the present invention is shown in Figure 14(A) in a longitudinal cross section of the multi-column writer tool, and in Figure 14(B) in a detailed view of a portion containing the lenses and including one embodiment of a multi-lens holder device. [Example]

[0045] The detailed discussion of examples or exemplary embodiments of the present invention provided below discloses the basic idea, implementation, and further advantageous developments of the present invention. It should be clear to those skilled in the art to arbitrarily combine some or all of the embodiments discussed herein as deemed suitable for a particular application of the present invention. Throughout this disclosure, terms such as "advantageous," "exemplary," "typical," "preferably," or "preferred" refer to elements or dimensions that are particularly suitable—but not essential—for the present invention or an embodiment thereof, and can be modified, unless expressly required, if deemed suitable by those skilled in the art. It is understood that the present invention is not limited to the exemplary embodiments discussed below, which are provided for the purpose of illustrating the present invention and merely present preferred embodiments of the present invention. Within the scope of this disclosure, terms relating to the vertical direction, such as "up" or "down," should be understood with respect to the direction of a particle beam traversing an electromagnetic lens, which is considered to travel downward ("vertically") along the central (or longitudinal) axis. This vertical axis is generally identified (identified) with the Z direction that intersects with the X and Y directions.

[0046] charged particle lens

[0047] FIG. 1(A) shows an example of a charged particle lens 10 according to a first aspect of the present invention in longitudinal section, i.e., along a cross section through its central axis cx. For better clarity, the components are not drawn to scale. This lens may be used to embody the lens 10 of the writer tool 1 of FIG. 13 or the multi-column writer tool 40 of FIG. 14 (see below), in which case it is used as an objective lens, but it will be clear that it is suitable for use in many other particle-optical devices that may embody single-column or multi-column architectures, such as those disclosed in our U.S. Pat. Nos. 9,443,699 and 9,495,499, the disclosures of which are incorporated herein by reference.

[0048] The charged particle lens 10 includes a beam passage 11 for a charged particle beam 100 traversing the assembly, and a magnetic circuit assembly 20 including at least one permanent magnet 210, 211, a yoke body 25 having at least two gaps 290, 291, and an electromagnetic adjustment assembly 30 according to the present invention. The magnet typically has a residual magnetization of approximately 1 T and The yoke body 25 includes two yoke elements 250, 251, of which the outer yoke shell 251 also serves as the housing body 12 for the lens and is made of a highly magnetically permeable material; the yoke elements form at least two gaps 290, 291 at two different axial positions, in which the magnetic flux flowing through the magnetic circuit assembly induces a magnetic field that reaches the beam path 11. Furthermore, the electromagnetic adjustment assembly 30 includes at least one electromagnetic adjustment coil 31 disposed at an appropriate position between the two yoke elements 250, 251 and powered by a current source 34 to generate a magnetic field that generates an additional magnetic contribution to the magnetic circuit assembly. This magnetic field enables the electromagnetic adjustment assembly 30 to adjust the magnetic field in at least one of the two gaps 290, 291.

[0049] Depending on the strength of the magnetic lens effect, the charged particle beam 100 may also form a crossover xr within the beam path 11, i.e., the beam achieves a minimum lateral width while intersecting the central axis cx; the dotted (dashed) line symbolically shows the envelope of the charged particle beam as it propagates through the lens when placed in an exemplary particle beam exposure system (such as the lithography tool 1 of FIG. 13 or the multi-column lithography tool 40 of FIG. 14).

[0050] In typical configurations, the charged particle lens 10 may have the following exemplary dimensions: an overall height h1 of approximately 50 mm to 100 mm, and an internal height h2 of approximately 10 mm to 100 mm, typically less than the overall height h1, allowing the outermost yoke element 251, also referred to as the outer yoke shell, to serve as a housing and shield body for the lens assembly; an outer radius r1 of approximately 10 mm to 20 mm, allowing for placement in the multi-column writer tool 40 of FIG. 14; and an aperture radius r2 of approximately 0.1 mm to 5 mm, i.e., wide enough to allow for charged particle beam passage, and may also accommodate additional insert members (see FIG. 10 below). These magnet, gap, and electromagnetic adjustment assemblies typically have a thickness of approximately 1 mm to 5 mm, with the yoke elements having radial thicknesses of approximately the same dimensions. The size of the elements is selected to be appropriate for each application and charged particle device, but in the illustrated example the geometric dimensions are typically on the order of several millimeters.

[0051] The charged particle lens 10 is typically positioned in the particle beam exposure system so that its central axis cx coincides with the optical axis c5 of the exposure system (see FIG. 13); however, those skilled in the art will recognize that other relative positions may be selected depending on the application of the charged particle lens according to the present invention.

[0052] Magnetic circuit and electromagnetic adjustment assembly

[0053] In accordance with the present invention, the magnetic circuit assembly 20 and corresponding magnetic lens include an electromagnetic adjustment assembly 30 that includes at least one electromagnetic adjustment coil 31 and components for power supply and control thereof. As previously mentioned, the electromagnetic adjustment coil serves to adjust the magnetic flux density in the yokes and yoke gaps 290, 291. The adjustment coil 31 is driven by a current I0 provided by the power supply; the value of this current I0 is adjusted, for example, by monitoring the effect of the magnetic lens, e.g., by measuring imaging characteristics at the target site, and modifying the value of the current until a desired ("optimum") imaging effect is obtained.

[0054] A significant advantage of providing electromagnetic tuning coils in accordance with the present invention is the ability to in-situ tune the magnetic flux in the magnetic circuit, so that whenever there are changes in the magnetic properties of the magnetic lens assembly (such as magnet aging), the present invention provides for compensation of such changes using at least one electromagnetic tuning coil.

[0055] As shown in Figures 2(A) and 2(B), the electromagnetic conditioning coil 31 is supported within the assembly by one or more dedicated holder devices (or holder elements) 32. The electromagnetic conditioning coil 31 and its associated components (such as the holder devices) preferably have an essentially symmetrical ring shape with a common central axis c2 that preferably coincides with the central axis cx of the lens assembly. The holder devices 32 are configured to position the components in the spaces between the yoke elements. To allow for better visibility of the electromagnetic conditioning coil, only one holder device 32 is shown in Figure 2(A).

[0056] To enable the generation of magnetic flux, the electromagnetic conditioning coil 31 includes an electrical circuit comprising multiple windings of conductive material. This electrical circuit is powered by electrical current through electrical lines inside an electrically insulating interface 33 to the exterior of the magnetic lens assembly for connection to a power supply 34 of the electromagnetic conditioning assembly 30 (FIG. 1).

[0057] The interface 33 traverses the outer housing or outer yoke shell 251. To accomplish this, several holes may be drilled radially inward at different angular positions. It is important to consider the effect of these holes on the magnetic behavior of the yoke, as a significantly asymmetric grouping of holes can induce asymmetric effects in the generated magnetic field, which is usually undesirable. For example, a suitable configuration to address this issue may be to provide a set of holes, e.g., 16 holes, evenly distributed around the periphery, with the size of these holes being as small as possible while still achieving the cross-section required for the electrical lines inside the interface 33.

[0058] Conventional permanent magnet lenses can achieve accuracies within 1% to 5% of the target field strength due to the manufacturing range of the permanent magnets installed in such systems. By using an electromagnetic tuning assembly in accordance with the present invention, this range can be reduced to accuracies within 0.1% to 0.5% of the target field or even smaller, providing an order of magnitude smaller deviation from the desired field and therefore significantly better performance.

[0059] The electromagnetic adjustment coil is typically disposed in close proximity to the two or more permanent magnets 210, 211 and between the yoke elements 250, 251 (see FIG. 2(B)); in this case, it may need to be disposed during assembly of the lens since its location is highly encapsulated; nevertheless, the electromagnetic adjustment coil could also be added after initial assembly if appropriate technical measures, such as partial disassembly, are used or the components consist of interchangeable modules within the lens.

[0060] Referring to Figures 3-5, some embodiments of the present invention may provide a sector-type electromagnetic adjustment coil structure composed of multiple subelements 340 arranged around a common axis c2, which may preferably coincide with the central axis cx of the lens assembly. Figure 3 shows a schematic plan view of one set (met) of an example sector-type coil structure 348 having eight sector-shaped subelements 340. The subelements are preferably embodied as sectors 340, each having a subelement winding that forms a closed loop with a winding axis oriented radially outward or inward. By passing currents in opposite directions through adjacent subelement windings, the generated magnetic field (B-field) alternates between a positive radial direction and a negative radial direction. Figures 4 and 5 show another embodiment of a sector-type coil structure 344, including a four-sector structure. As can be seen from these figures, the sector-shaped subelements are preferably actuated to have different orientations of the magnetic field, e.g., alternating opposite radial directions, denoted Br and -Br, respectively. Figure 4 shows a perspective view of two subelements 341 of a four-sector structure, in which current I flows in opposite current directions, as indicated by the arrows along the winding path, and the resulting magnetic flux vectors, denoted Br and -Br, respectively, point radially inward and outward in an alternating arrangement; Figure 5 shows a plan view of four subelements 341 of structure 344. This four-sector structure can be used to realize a magnetic quadrupole structure. Such a structure, including sector elements with magnetic flux in different directions, embodies a magnetic multipole structure that can be used to intentionally create and / or compensate for azimuth changes; for example, it can be used to oppose a permanent magnet by applying multipole-like features, while selected regions may be intentionally left air gapped. The arrangement of such a structure with multiple sectors follows the same rules as circular electromagnetic tuning coils and is discussed in the following section.The value of the current I driving the sector coils can be adjusted, for example, in substantially the same way as the current I described above, i.e., by monitoring the effect of the magnetic lens, for example by measuring the imaging characteristics at the target location, and modifying the value of the current until the desired ("optimum") imaging effect is obtained. Of course, in more complex configurations, one or more magnetic sensors may be provided at appropriate locations in the magnetic circuit, forming a control loop which can be used to control and modify the magnetic flux by appropriate adjustment of the currents I and I.

[0061] In many configurations, symmetric lens assemblies are particularly advantageous. Each magnetic field in a radially symmetric magnetic lens arrangement includes an axial component and a radial component, i.e. TIFF0007811572000002.tif6150; Radial component TIFF0007811572000003.tif6150 is of minor importance, and as a result, the axial component of the magnetic field TIFF0007811572000004.tif6150 is used for the lens effect. The strength (magnitude) of the axial component of the magnetic field at the position of the central axis cx as a function of the longitudinal coordinate is shown in FIG. 1(B) (solid line 61 shows the "original" magnetic field, dotted line 62 shows the magnetic field modified / corrected by the adjustment coil according to the invention); axial magnetic field Typical values ​​for the peak value of TIFF0007811572000005.tif6150 are of the order of 0.1 T in applications where the charged particles are electrons. As mentioned above, the magnetic circuit generates two regions near the gaps 290, 291 with (relatively) high magnetic field strengths that function as two sequentially arranged magnetic lenses with well-defined focal lengths and optical aberrations in the beam path 11. The magnetic coupling of the two lenses via the common yoke body 25 strongly reduces the effect of stray (leakage) magnetic fields in any other regions that would otherwise be inevitably associated with permanent magnets in particle lenses of conventional layouts.

[0062] Electromagnetic adjustment coil arrangement

[0063] The placement of electromagnetic conditioning coils according to the present invention within a magnetic lens assembly can have a significant impact. For example, as shown in FIG. 6A, electromagnetic conditioning coil 231 can be placed in a corner region surrounding the gap between the two yoke elements, preferably near gaps 290 and 291, in the example shown at the upper corner of the interior of the outer yoke shell. The magnetic field resulting from this electromagnetic conditioning coil 231 flows through the two yokes and the upper permanent magnet, as shown by curve 64 in FIG. 6B, which represents the axial magnetic flux density along the longitudinal axis cx. In one exemplary configuration, the upper permanent magnet can have a dominant magnetization directed radially outward. The current polarity in the electromagnetic conditioning coil can be selected so that the generated magnetic field acts against the magnetization direction of the permanent magnet (see the magnetic field lines induced by the electromagnetic conditioning coil in the yokes and permanent magnets, indicated by reference numeral 66). This reduces the magnetic field strength in the upper gap 290, as shown in FIG. 6B. The dashed line 61 represents the unperturbed magnetic field produced by the permanent magnet, while the dotted line 64 represents the reduction in magnetic field strength induced (caused) by the electromagnetic conditioning coil. Furthermore, it can be seen that the conditioning field can also affect the magnetic flux and field strength of the lower magnetic lens, albeit to a lesser extent.

[0064] In another exemplary embodiment of the present invention, as shown in FIG. 1A, the electromagnetic tuning coil 31 may be positioned longitudinally centered between two adjacent permanent magnets and radially centered between two yokes. In such a configuration, the magnetic flux density generated by the coil acts radially inward at one permanent magnet and radially outward at the other permanent magnet (as symbolically shown by magnetic field lines 65 in FIG. 1A). This results in an anti-symmetric tuning effect on the two lenses, as can be seen from the dotted line 62 for the magnetic flux intensity.

[0065] Furthermore, in many suitable configurations, multiple electromagnetic adjustment coils can be combined. For example, a coil at a lens corner that has a dominant effect on one magnetic lens can be combined with a coil located in the gap between two permanent magnets that produces an antisymmetric effect. Such a configuration is shown in FIG. 9A, which shows three electromagnetic adjustment coils 531, 532, and 533 arranged at different positions along the longitudinal axis. This can be used to induce localized changes in the two magnetic lenses and / or to counteract unintentional inherent asymmetries in the magnets and / or yokes. Furthermore, for example, the central adjustment coil 532 can include a sectorial coil, symbolically represented by two rectangles on either the left or right side of FIG. 9A.

[0066] Any of the adjustment coils 31, 231, 531, 532, 533 described above may comprise or be replaced by sector coils, for example of the type described above with reference to Figures 3 to 5.

[0067] Permanent magnet

[0068] The permanent magnets 210 and 211 act as a source of magnetic flux Φ of the magnetic circuit embodied in the magnetic circuit assembly 20 .

[0069] FIG. 7 shows a preferred form of permanent magnet 21 suitable for use as a component of the magnetic circuit assembly of an example lens according to the present invention (e.g., as one of permanent magnets 210, 211 in FIG. 1(A)). The magnet has a predominant radial magnetization for a rotationally symmetric magnet. FIG. 7(A) is a schematic perspective view, and FIG. 7(B) is a schematic cross-sectional view along the longitudinal axis c1 of magnet 21.

[0070] In many configurations, it may be useful for such magnets to be constructed from multiple sectors, as shown in Figures 8(A)-(D). Figures 8(A)-(D) show four exemplary variations of ring magnet 21 having net radial magnetization in their respective schematic cross-sections. Note that the components of the ring magnet are shown exploded in Figures 8(B), (C), and (D) for better clarity. The radial magnetization directions also provide preferred positions, i.e., the inside and outside of such ring magnet, for yoke elements that capture magnetic flux from either pole of the magnet and direct it toward the designed (intended) positions of gaps 290, 291 between the yoke elements (see Figure 1(A)). Each of the magnet elements will have a magnetization oriented primarily radially, as indicated by the dashed arrows in Figures 8(A)-(D), so that, for example, the "north" pole N faces toward the interior space of the ring magnet, while the outside (of the ring magnet) has a "south" pole S of magnetization. Permanent magnet elements with radial magnetization as shown are commercially available and are made of ferromagnetic materials such as sintered NdFeB, SmCo5, or ferrite. The magnet elements 240, 241, and 242 of the composite magnet of Figures 8(B)-(D) are joined by adhesive bonding, clamping, or other suitable means. The number of magnet elements forming each ring magnet can be any number, such as one, two, three, four, six, or more, depending on the dimensions of the composite element (e.g., height and radius) and the desired dimensions of the permanent magnet 21.

[0071] 7, in many embodiments, the permanent magnet 21 may be embodied as a ring-shaped piece and may include multiple layers of ring-shaped segment magnets 220 stacked along a common central axis c1. In such a segmented magnet, each layer or segment contributes to the total magnetic flux of the n-layer magnet. Part of TIFF0007811572000006.tif11150 Compose TIFF0007811572000007.tif6150.

[0072] Housing body

[0073] In many embodiments, the yoke body 25 also functions as the housing 12 for the lens 10. The yoke body is comprised of an inner yoke element 250 and an outer yoke element 251. The inner yoke element 250 is often and typically embodied as a hollow cylinder having an aperture radius r2 and a length h2 sufficient to exceed the height of at least the stacked permanent magnets and temperature control elements; the outer yoke element 251, in this case, may also be embodied as a cylindrically symmetrical shape of height h1 with an aperture radius r2 and an outer radius r1 sufficient to cover the thickness of each yoke element and the thickness of the magnets disposed between them. The outer yoke may advantageously have a double "U"-shaped longitudinal cross section (FIG. 1(A)); in other words, the outer yoke includes a central body portion formed as a hollow cylinder that may be concentric with the hollow cylinder of the inner yoke element, and further has two disk-shaped end portions with a central hole. The hollow space of the yoke elements thus surrounds the beam passage 11, which has a radius r2 and a height h1 along the longitudinal axis cx. Magnetic circuit gaps 290, 291 are provided between the axially outer end faces of the inner yoke element and the corresponding axially inner end faces of the outer yoke element, representing the respective pole pieces of the magnetic circuit 20. The radial thickness of the hollow cylinder is typically, but without loss of generality, on the order of a few millimeters, and the height of the assembly is on the order of tens of millimeters. Due to their shape, the inner and outer yoke elements, which form the housing body of the lens, can enhance and focus the magnetic flux generated by the magnets. The outermost yoke element also functions as a shield against magnetic flux in both the radial and axial directions, since its spatial shape and material concentrate the magnetic flux within the dimensions of radius r1 and height h1.

[0074] Electrical inlay (insert material)

[0075] In accordance with a further aspect of the present invention as shown in FIG. 9, the charged particle lens 10 may advantageously include a sleeve insert member or inlay 50 (FIG. 9(A)) inserted into the beam path 11 along the optical axis cx. Accordingly, the physical dimensions of the inlay are appropriately selected relative to the dimensions discussed above, such as the lens radius r2 and height h1. The inlay may include a plurality of beam control elements 52-54, including one or several electrically active elements employed to generate an adjustable electric field 65 (dashed curve in FIG. 9(B)) superimposed on a magnetic field 61 (solid curve in FIG. 9(B)) in the beam path. The axial component E of the electric field Z (i.e., along the vertical direction) is 10 5 It will have typical values ​​of peak magnitude on the order of 1000 V / m.

[0076] In many forms of the inlay, the beam control elements 52-54 are generally ring-shaped components that serve as electrically active elements and are arranged in a stack along a central axis c3, with their geometric axes oriented concentrically and parallel to the central axis cx of the lens. In many forms of the invention, it is useful for all control elements to have a common inner radius r2; so that they define a passage hole 55 that traverses the lens and serves as a channel for the charged particle beam 100 during operation of the charged particle lens. Additionally, it may be useful to insert a smaller aperture 54 (see below) for beam calibration purposes.

[0077] In the embodiment shown in FIG. 9(A), the beam control elements are embodied (configured) with two Einzel lenses 52a, 52b and two multipole electrodes 53a, 53b, all made of a conductive material. For example, each multipole electrode can be embodied (configured) as a composite metal ring composed of multiple sections having equal arc lengths, e.g., four, six, or eight sections (see FIG. 11 ), without loss of generality; their (radial) thickness is typically less than 2 mm, and their lengths are between 5 mm and 20 mm. Furthermore, a conductive ring-shaped aperture 54 is preferably disposed between the two multipole electrodes 53a, 53b; this component is referred to herein as a “calibration aperture.” The electrically active elements are preferably connected to their own power supply units 722a, 723a, 722b, 723b as shown in FIG. 10, so that their electrostatic potentials can be individually adjusted; in one variation, the power supplies can be combined in a common multi-channel power supply 70 providing individual supply voltages. The calibration apertures can be controlled by the power supply 70 or a separate dedicated electrical control unit 71. Finally, the electrically active elements are electrically isolated from each other and terminated at both ends by elements called field termination caps 51a, whose electrical potentials represent "local earths" or reference points. The field termination caps serve to confine the electric field to the passage space of the inlay; thus, they provide a clearly defined "field boundary" of the inlay relative to surrounding components (such as other particle-optical columns 400, see FIG. 14). Some spaces on the inlay mounting body 51 between the field termination cap(s) and other electrical components may be electrically insulating, for example, by a vacuum or a filler material using a non-conductive, preferably voltage-resistant, material such as a ceramic.

[0078] In many embodiments of the invention, the various elements 52-54 of the inlay 50 are supported and held together by a mounting body 51 having a hollow cylindrical shape (e.g., inner radius r3, outer radius r2, and height h1), which can typically be made of an electrically insulating material such as ceramic or plastic; however, at least the portion 51a facing the charged particle beam can be covered with a conductive material and connected to a "drain" to avoid charging up. The electrode elements can be embodied, for example, as separate ring-shaped elements 52a, 52b, 53a, 53b, 54 joined and held together within the body, or as conductive coatings 51a formed on the inner circumferential surface of the ring body, each having a limited shape and area.

[0079] The inlay allows the precision of optical properties, such as the focal length of a charged particle lens (limited by the manufacturing precision of the permanent magnets, assembly accuracy, and adjustability limitations of at least one temperature-controlled element), to reach accuracies of 1 ppm to 5 ppm above or below the target value—thus enabling "ultra-high precision" tuning. Some embodiments of the invention may also include built-in correction means that can be used to overcome limitations related to, for example, magnet aging effects, since the electric field can be adjusted and controlled with precision in the parts-per-million regime without resolution during lens use, i.e., "in situ tuning." Furthermore, the voltage of the beam-control element can be adjusted in combination with other optical and electrical active elements of the system to change the properties of the particle beam exposure apparatus 1, e.g., with respect to optical properties such as aberrations, field, etc.

[0080] FIG. 11 shows a cross-section of an example of a multipole electrode in an inlay. The multipole electrode includes multiple rods (or strips) 530 (partially annular in cross-section), each of which can be controlled with an individual electric potential by its own external power supply unit 70. Furthermore, a global offset voltage can be applied to cause them to behave as additional electrostatic lenses. By applying different voltages to individual rods, various electrostatic field configurations, such as dipole, quadrupole, or higher order, can be realized for the purpose of shaping the particle beams intersecting at their corresponding transversal sections of the optical axis. For a typical application according to the configuration of FIG. 10, the voltages applied to the rods are typically on the order of up to several tens of volts. Such beam shaping can be used to compensate for errors due to imperfections in the optical system, such as magnetic inhomogeneities, mechanical manufacturing, and / or assembly accuracy. In this regard, when a multipole is used as a dipole, it can correct the beam position relative to the optical axis c3, but its orientation in the plane defined by the X and Y axes (FIG. 11) can be arbitrary, provided that at least four different voltages are applied to the rods: +V1 (rods with (linear) hatching on the right side of the page), −V1 (rods with (linear) hatching on the left side of the page), +V2 (rods with checkerboard hatching on the top side of the page), and −V2 (rods with checkerboard hatching on the bottom side of the page). Furthermore, when a multipole is used as a quadrupole or higher-order multipole, it can compensate for astigmatism or other higher-order distortions by applying appropriate voltages to the individual rods in a manner similar to that of a dipole.

[0081] It should be noted that any multipole electrode can be used as a (quasi-)static element or as a dynamic element, i.e., with a time-varying voltage, depending on the application. Those skilled in the art will appreciate that the above uses of beam control elements are described as exemplary applications and are not intended as limitations on the functionality achievable by the present invention.

[0082] 10 and 12, as previously mentioned, in some embodiments of the present invention, inlay 50 may include a passive element 54, referred to as a "calibration aperture," that acts as a stop element to deflect (remove) stray portions of particle beam 120. FIG. 12 shows an enlarged, detailed longitudinal cross-section of an example calibration aperture. The calibration aperture includes a body 540 that encloses a calibration bore 541, an aperture having a small radius r4 along axis c3. The aperture functions to limit the size of beam 100 traversing the charged particle lens by absorbing portion 120 of the beam traveling outside the aperture, so that only portion 110 (of the beam inside the aperture) can pass through the aperture. In a preferred form of the invention, one of the upstream inlay elements, e.g., multipole electrode 53a, can vary the lateral position of the beam relative to the longitudinal axis, e.g., by varying the voltage applied to selected electrodes of the multiple electrodes forming an electric dipole field. The multipole can also be used for beam alignment. The charged particle lens 10 is advantageously configured to form a crossover xr at or near (e.g., 10 mm or less) the longitudinal location of the calibration aperture 54. Thus, the beam diameter is smallest near the aperture.

[0083] In many embodiments of the invention, particularly in particle beam devices used as multi-beam writing tools, such as single-column tool 1 or multi-column tool 40 (the latter see below), the charged particle beam is split into multiple beamlets pb that can selectively pass through a pattern definition system 4, 43 without (e) or with (f) additional lateral deflection (FIG. 12) introduced by the pattern definition system. Such deflection is introduced to prevent certain beamlets from reaching the target, and thus to define discrete writing patterns. The deflected beamlets do not pass through the calibration bore 541 but reach a region of the body 540 of the "calibration aperture" beside (or away from) the calibration bore 541 and are absorbed there; absorption of the beam 120 will cause the generation of electric charge-up in the components, which can be removed, i.e., drained off, for example, by electrical connection of the beam aperture to a measurement device 714 (FIG. 10) that allows monitoring of the amount of absorbed beam. The beamlets impinging on the "calibration aperture" also cause the transfer of thermal energy to the "calibration aperture" and, consequently, to the inlay element surrounding it and ultimately to the magnetic lens assembly. This needs to be taken into account for tuning the magnetic lens with at least one temperature control element.

[0084] Lithography equipment

[0085] FIG. 13 is a schematic longitudinal cross-sectional view of an example of a single-column writer tool 1. The tool includes an exemplary embodiment of the lens of the present invention; for example, the objective lens 10 of the tool includes a charged particle lens according to an embodiment of the present invention. The writer tool uses a charged particle beam, which can be electrons or ions (e.g., positively charged ions). The writer tool 1 includes a vacuum housing 480 for the multi-column charged particle optics and a base member 470 to which the multi-column charged particle optics is mounted. Mounted on top of the base member is an XY stage 460, e.g., a laser interferometer-controlled air-bearing vacuum stage, using an appropriate manipulation system, on which a target 450, preferably a mask for lithography purposes or a silicon wafer in the case of a direct-write writer tool, is positioned. The target, which may include, for example, a resist layer, can then be exposed by the writer's charged particle beam.

[0086] This form of single-column optical system preferably includes a central axis c5, illumination optics 3 including a charged particle source 7, a condenser 8 that supplies a wide, telecentric charged particle beam ib to a pattern definition system 4 (which is adapted to pass the beam only through a number of apertures that define the shape of the sub-beams ("beamlets") passing through the apertures (beam shaping devices), and charged particle projection optics 5 that typically perform demagnification and also provide energy (the projection optics 5 is composed of a number of charged particle lenses arranged in succession, which preferably include electrostatic and / or magnetic lenses, and possibly other particle-optical devices). 13, the projection optics include, for example, a first charged particle lens 9, e.g., an electrostatic immersion lens, while a second lens 10, which is located downstream of the first lens, is implemented using a charged particle lens (e.g., FIG. 9(A)) according to one embodiment of the present invention. Within the charged particle lens 10, a "calibration aperture" 54 is symbolically implemented; as described above, some portion (f) of the beam deflected by the pattern definition device 4 is absorbed, while other portion (e) traverses the optical column unimpeded to expose the pattern onto the target 450.

[0087] The pattern definition device 4 functions to form from the particle beam a plurality of so-called beamlets which contain information about the pattern to be transferred onto the target. The structure, operation and data processing of the pattern definition device 4 and its controller 404 are disclosed in commonly owned US Pat. Nos. 9,443,699 and 9,495,499, the contents of which are incorporated herein by reference.

[0088] 14(A) and 14(B) show an example of a multi-column writer tool 40. The tool 40 includes, in each column, an instance of an exemplary embodiment of the lens of the present invention; for example, the objective lens 10 in the tool includes a charged particle lens according to an embodiment of the present invention. The writer tool uses multiple charged particle beams, which may be electrons or ions (e.g., positively charged ions). As can be seen from FIG. 14(A), which shows a schematic longitudinal cross-section of the multi-column writer tool 40, the writer tool 40 includes a vacuum housing 48 for the multi-column charged particle optics and a base member 47 to which the multi-column charged particle optics is mounted. Mounted on top of the base member is an XY stage 46, e.g., a laser interferometer-controlled air-bearing vacuum stage, using an appropriate manipulation system, on which a target 45, preferably a mask for lithography purposes or a silicon wafer in the case of a direct write writer tool, is positioned. The target, which may include, for example, a resist layer, can then be exposed by the writer's charged particle beam.

[0089] This form of multi-column optical system includes a plurality of sub-columns 400 (the number of columns shown is reduced in the figure for better clarity and is representative of the much larger number of columns present in an actual implementation of the multi-column device), preferably with the sub-columns having the same configuration and arranged with their parallel axes c5 side-by-side. Each sub-column comprises an illumination system 42 including a charged particle source 41, supplying a wide, telecentric charged particle beam to a pattern definition system 43 (adapted to pass the beam only through a number of apertures, which define the shape of the sub-beams ("beamlets") passing through the apertures (beam shapers), and a charged particle projection optics 44, which typically performs demagnification and / or energy application (sequentially arranged charged particle lenses, preferably including electrostatic and / or magnetic lenses, possibly other particle-optical devices). In the embodiment shown in Figure 14, the projection optics includes, for example, a first charged particle lens 44a, e.g., an electrostatic immersion lens, while the second lens 10, which is located downstream of the first lens, is implemented using a charged particle lens (e.g., Figure 1(A)) according to one embodiment of the present invention.

[0090] FIG. 14 shows a detailed view of an example of lenses 10 used as secondary lenses and their supporting elements. Each secondary lens 10 of the sub-columns can be attached to a reference plate 49, which is preferably attached to the column base plate 47 or a specific flange 48 of the vacuum chamber by suitable fastening means 49b. The reference plate 49 can be made of a suitable base material with low thermal expansion, such as a ceramic material based on silicon oxide or aluminum oxide, which has the advantages of being lightweight, having a high modulus of elasticity, and having high thermal conductivity, and can be appropriately coated, at least in its relevant parts, with a conductive coating to avoid charging (by draining static charges). Furthermore, the reference plate 49 can include apertures 49a that overlap (match) with the beam paths 11 of the lenses 10 of each sub-column.

[0091] All or part of the above embodiments and examples can be described as the following supplementary notes, but are not limited thereto. [Appendix 1] A charged particle lens configured to modify a charged particle beam of a charged particle optical system. The charged particle lens extends essentially along a longitudinal axis and has a passage space for allowing the passage of a charged particle beam. The charged particle lens includes a magnetic circuit assembly. The magnetic circuit assembly at least one permanent magnet, and Yoke body Includes. The yoke body is composed of at least two yoke elements, of which a first yoke element constitutes an inner yoke shell arranged to surround the passage space, and a second yoke element constitutes an outer yoke shell arranged to surround the inner yoke shell, the yoke elements being arranged circumferentially around the longitudinal axis and including a highly permeable material. The at least one permanent magnet is disposed between the at least two yoke elements and circumferentially surrounding the inner yoke shell, and the at least one permanent magnet includes a permanent magnetic material whose two magnetic poles are magnetically oriented toward the respective yoke elements. In the magnetic circuit assembly, the at least one permanent magnet and the yoke body are configured to guide the magnetic flux density generated from the at least one permanent magnet through the yoke body, form a closed magnetic circuit through at least two gaps formed between the respective (corresponding) axial faces of the different yoke elements, and induce (generate) a magnetic field within the gaps that extends inward into the passage space. The charged particle lens includes an electromagnetic adjustment coil disposed between the inner yoke shell and the outer yoke shell and configured to be driven by an adjustable supply current, the current in the electromagnetic adjustment coil flows substantially circumferentially around the longitudinal axis, and the electromagnetic adjustment coil is configured to modify the magnetic flux of the magnetic circuit to cause a change in magnetic flux density in at least one of the at least two gaps. [Appendix 2] In the charged particle lens according to Appendix 1, The electromagnetic conditioning coil further comprises a sector-type electromagnetic conditioning coil structure including two or more sector coil elements; each sector coil element is configured with a respective radially oriented (inward or outward) general winding axis; and the sector coil elements of the sector-type electromagnetic conditioning coil are angularly offset circumferentially relative to each other around the longitudinal axis. [Appendix 3] In the above-mentioned charged particle lens, particularly the charged particle lens described in Appendix 2, The electromagnetic conditioning coil and the sector-type electromagnetic conditioning coil structure each have an electrical interface to the exterior of the charged particle lens for supplying respective currents to the coil and coil elements. [Appendix 4] In the above-mentioned charged particle lens, particularly the charged particle lens described in Appendix 1, The electromagnetic tuning coil includes an electrical interface to the exterior of the charged particle lens configured to supply current to the coil. [Appendix 5] In the above-mentioned charged particle lens, particularly the charged particle lens described in Appendix 3 or 4, The electrical interface includes a passageway formed in the outer yoke shell. [Appendix 6] The charged particle lens according to any one of Appendices 1 to 5, The electromagnetic conditioning coil, or both the electromagnetic conditioning coil and the sector-type electromagnetic conditioning coil structure provided therewith, are configured to cause a redistribution of magnetic flux between two or more branches of the magnetic circuit, thereby causing a change in magnetic flux density in at least two gaps. [Appendix 7] In the above-mentioned charged particle lens, particularly the charged particle lens described in any one of Appendices 1 to 5, The electromagnetic adjustment coil or both the electromagnetic adjustment coil and the sector-type electromagnetic adjustment coil structure provided therewith are configured to cause a modification of the magnetic flux that primarily affects one of two or more branches of the magnetic circuit, causing a change in the magnetic flux density in the corresponding gap. [Appendix 8] The charged particle lens according to any one of Appendices 1 to 7, Two or more electromagnetic tuning coils are disposed at different locations associated with different components of the magnetic circuit assembly configured to differentially tune the magnetic fields in the two gaps. [Appendix 9] The charged particle lens according to any one of Appendices 1 to 8, The charged particle lens further includes a holder element configured to hold both the electromagnetic adjustment coil or the holder element (correctly, the electromagnetic adjustment coil) and a sector-type electromagnetic adjustment coil structure provided thereon at a predetermined position between the at least two yoke elements of the yoke body. [Appendix 10] The charged particle lens according to any one of Appendices 1 to 9, The second yoke element forms a housing body for the charged particle lens that encloses the other components of the magnetic circuit assembly, including all other yoke elements. [Appendix 11] The charged particle lens according to any one of Appendices 1 to 10, The at least one permanent magnet has a magnetization that is substantially radially oriented. [Appendix 12] The charged particle lens according to any one of Appendices 1 to 11, The at least one permanent magnet is segmented according to two or more layers stacked along its longitudinal axis, and / or divided into two or more sectors arranged around its longitudinal axis, It consists of at least two subelements. [Appendix 13] In the above-mentioned charged particle lens, particularly the charged particle lens described in Appendix 12, At least one temperature control device is disposed between each two of the plurality of sub-elements. [Appendix 14] The charged particle lens according to any one of Appendices 1 to 13, the charged particle lens having a generally rotationally symmetric shape along the longitudinal axis; A plurality of components of the magnetic circuit assembly, namely: the at least one permanent magnet, and the yoke body, and The electromagnetic adjustment coil is arranged concentrically (coaxially) with the longitudinal axis and has a basic shape corresponding to a hollow cylinder or hollow polygonal prism. [Supplementary Note 15] An electromagnetic lens including the charged particle lens according to any one of Supplementary Notes 1 to 14, and a sleeve insert member inserted into the passage space along the longitudinal axis. The sleeve insert member encloses a beam path extending along its longitudinal axis and having a radius smaller than the radius of the path space of the charged particle lens; The sleeve insert member includes a mounting body having an at least partially conductive portion and at least one conductive electrode element; the at least one conductive electrode element is configured to have an electric potential applied to it via a power source relative to a potential of the conductive portion of the mounting body to generate an electrostatic field within the beam passage; the electrode elements are configured to form a particle-optical lens in combination with a magnetic field within the beam path at one or more gaps; The focal length of the charged particle optical lens is adjustable by modifying the electrical potential applied to the electrode elements. [Appendix 16] The electromagnetic lens according to Appendix 15, The longitudinal axis of the sleeve insert member overlaps (coincides with) the longitudinal axis of the charged particle lens; the inner yoke shell extends along the longitudinal axis and circumferentially surrounds the sleeve insert member; at least two gaps in the magnetic circuit are positioned at either axial end of the inner yoke shell; each gap generates a defined magnetic field that extends radially inward into the passage space or beam passage; the electrostatic field is generated by at least one of a plurality of electrode elements of the sleeve insert member that are configured to at least partially overlap with the magnetic field. [Appendix 17] The electromagnetic lens according to appendix 15 or 16, At least one of the plurality of electrode elements comprises an electrostatic multipole electrode comprising a plurality of sub-electrodes uniformly (evenly) arranged circumferentially around the longitudinal axis; the (multipole) electrode is connectable to a multi-channel power supply unit which provides an individual potential to each electrode. [Appendix 18] The electromagnetic lens according to any one of Appendices 15 to 17, the electrode elements include beam aperture elements that define a limiting aperture having a defined radius centered on the longitudinal axis; the limiting aperture is configured to limit a lateral width of a charged particle beam propagating along the longitudinal axis; The beam aperture element is connected to a current measuring device configured to measure the amount of the charged particle beam absorbed in the beam aperture element. [Supplementary Note 19] A charged particle optical device including at least one of the charged particle lens according to any one of Supplementary Notes 1 to 14 and the electromagnetic lens according to any one of Supplementary Notes 15 to 18. The charged particle optical device is configured to affect a charged particle beam propagating along its longitudinal axis through a lens; the lens is part of a particle-optical system of the charged particle optical device. [Supplementary Note 20] The charged particle optical apparatus according to Supplementary Note 19, the charged particle optical device is configured as a multi-column system including a plurality of particle optical columns; Each column is configured to use a respective particle beam and includes a respective particle-optical system that includes a respective arrangement of charged particle lenses or electromagnetic lenses.

[0092] Within the scope of the entire disclosure of the present invention (including the claims and drawings), modifications and adjustments of the embodiments are possible based on the basic technical concept thereof. Furthermore, within the scope of the entire disclosure of the present invention, various combinations and selections (including "non-selection") of various disclosed elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) are possible. In other words, the present invention naturally includes various modifications and alterations that would be possible by a person skilled in the art in accordance with the entire disclosure, including the claims and drawings, and the technical concept of the present invention. In particular, with regard to the numerical ranges described herein, any numerical value or subrange included within the range should be construed as being specifically described, even if not otherwise specified.

[0093] Furthermore, the reference numerals in the drawings attached in the claims are intended solely to aid in the understanding of the invention and are not intended to limit the invention to the embodiments and examples shown.

[0094] Furthermore, the entire contents of each of the above references are incorporated herein by reference. [Explanation of symbols]

[0095] 1. Charged particle optical system 10 Charged particle lens 11 Passage space (or beam passage) 12 Housing body 20 Magnetic circuit assembly 21 Permanent magnets 25 yoke body 31 Electromagnetic adjustment coil 32 Holder element (holder device) 33 Electrical Interface 40 Multi-column System 50 Sleeve insert member 51 Mounting body 51a Conductive part of 51 52a, 53a, 52b, 53b conductive electrode elements 53 Electrostatic Multipole Electrode 54 Beam Aperture Element 55 Beam passage (or passage hole) 61 Magnetic Field 65 Electrostatic Field 70 Power supply 71 Current measuring device 100 charged particle beam 210, 211 Permanent magnet materials 250, 251 Yorkshire 290, 291 Gap 348, 344 Sector-type electromagnetic adjustment coil structure 530 sub-electrode 540 Delimiting Opening 723 Multi-Channel Power Supply Unit cx, c1, c3 vertical axis r2 Radius of 11 r3 55 radius r4 540 (limited) radius

Claims

1. An electromagnetic lens comprising a charged particle lens configured to modify a charged particle beam of a charged particle optical system (1) and a sleeve insert member (50), the charged particle lens extends essentially along a longitudinal axis (cx) and has a passage space (11) for allowing passage of a charged particle beam (100); the charged particle lens includes a magnetic circuit assembly (20); The magnetic circuit assembly (20) at least one permanent magnet (21; 210, 211), and ・Yoke body (25; 250, 251) Including, The yoke body (25) is composed of at least two yoke elements (250, 251), and of the at least two yoke elements (250, 251), a first yoke element constitutes an inner yoke shell (250) arranged to surround the passage space (11), and a second yoke element constitutes an outer yoke shell (251) arranged to surround the inner yoke shell, and the yoke elements are arranged around the longitudinal axis (cx) and include a highly permeable material. the at least one permanent magnet (21) is disposed between the at least two yoke elements and circumferentially surrounding the inner yoke shell, and the at least one permanent magnet (21) includes a permanent magnet material (210, 211) whose two magnetic poles are magnetically oriented toward the respective yoke elements; In the magnetic circuit assembly (20), the at least one permanent magnet and the yoke body are configured to guide magnetic flux density generated from the at least one permanent magnet through the yoke body, form a closed magnetic circuit through at least two gaps (290, 291) formed between respective axial faces of different yoke elements, and induce a magnetic field (61) inwardly reaching the passage space within the gaps; the charged particle lens (10) includes an electromagnetic conditioning coil (31) disposed between the inner yoke shell (250) and the outer yoke shell (251) and configured to be driven by an adjustable supply current, the current in the electromagnetic conditioning coil (31) flowing substantially along a circumferential direction around the longitudinal axis, the electromagnetic conditioning coil (31) configured to modify the magnetic flux of the magnetic circuit to cause a change in magnetic flux density in at least one of the at least two gaps (290, 291); The sleeve insert member (50) is inserted into the passage space (11) along the longitudinal axis, The sleeve insert member (50) encloses a beam passage (55) extending along its longitudinal axis and having a radius (r3) smaller than the radius (r2) of the passage space (11) of the charged particle lens; The sleeve insert member (50) includes a mounting body (51) having an at least partially conductive portion (51a) and at least one conductive electrode element (52a, 53a, 52b, 53b); the at least one conductive electrode element is configured to have an electric potential applied to it via a power source (70) relative to a potential of the conductive portion (51 a) of the mounting body (51) to generate an electrostatic field (65) inside the beam passage; the electrode elements are configured to form a particle-optical lens in combination with a magnetic field (61) inside the beam path (55) at one or more gaps (290, 291); The focal length of the charged particle lens is adjustable by modifying the electrical potential applied to the electrode elements. An electromagnetic lens characterized by:

2. 2. The electromagnetic lens according to claim 1, a longitudinal axis (c3) of the sleeve insert member (50) overlaps with a longitudinal axis (cx) of the charged particle lens, the inner yoke shell (250) extends along the longitudinal axis (c3) and circumferentially surrounds the sleeve insert member (50), at least two gaps (290, 291) of the magnetic circuit are positioned at either axial end of the inner yoke shell, each gap generates a defined magnetic field (61) that extends inwardly into the passage space or beam passage (11, 55), and the electrostatic field (65) is generated by at least one of a plurality of electrode elements (52a, 53a, 52b, 53b) of the sleeve insert member that is configured to at least partially overlap with the magnetic field; An electromagnetic lens characterized by:

3. 2. The electromagnetic lens according to claim 1, At least one of the plurality of electrode elements includes an electrostatic multipole electrode (53) including a plurality of sub-electrodes (530) uniformly arranged along a circumferential direction around the longitudinal axis (c3), the multipole electrode being connectable to a multi-channel power supply unit (723) that provides an individual potential to each electrode. An electromagnetic lens characterized by:

4. 2. The electromagnetic lens according to claim 1, the electrode element includes a beam aperture element (54) that defines a limiting aperture (540) having a defined radius (r4) centered about the longitudinal axis (c3); the limiting aperture (540) is configured to limit a lateral width of the charged particle beam (100) propagating along the longitudinal axis; The beam aperture element is connected to a current measuring device (71) configured to measure the amount of the charged particle beam absorbed in the beam aperture element. An electromagnetic lens characterized by:

5. A charged particle optical device including the electromagnetic lens according to any one of claims 1 to 4, the charged particle optical device is configured to influence a charged particle beam (e, f) propagating along its longitudinal axis through a lens, the lens being part of a particle-optical system (3, 5) of the charged particle optical device; A charged particle optical device comprising:

6. 6. A charged particle optical device according to claim 5, the charged particle optical device is configured as a multi-column system (40) including a plurality of particle optical columns; Each column is configured to use a respective particle beam and includes a respective particle-optical system including a respective arrangement of charged particle lenses or electromagnetic lenses. A charged particle optical device comprising:

7. 2. The electromagnetic lens according to claim 1, The electromagnetic adjustment coil (31) further comprises a sector-type electromagnetic adjustment coil structure (348, 344) including two or more sector coil elements, each sector coil element configured with a respective radially oriented winding axis, and the sector coil elements of the sector-type electromagnetic adjustment coil (348, 344) being angularly offset circumferentially relative to one another about the longitudinal axis. An electromagnetic lens characterized by:

8. 8. The electromagnetic lens according to claim 7, The electromagnetic adjustment coil (31) and the sector-type electromagnetic adjustment coil structure each have an electrical interface to the outside of the charged particle lens for supplying current to the coil and coil elements, respectively. An electromagnetic lens characterized by:

9. 2. The electromagnetic lens according to claim 1, The electromagnetic adjustment coil (31) comprises an electrical interface (33) to the exterior of the charged particle lens, configured to supply current to the coil. An electromagnetic lens characterized by:

10. 9. The electromagnetic lens according to claim 8, The electrical interface includes a passageway formed in the outer yoke shell. An electromagnetic lens characterized by:

11. 2. The electromagnetic lens according to claim 1, The electromagnetic adjustment coil (31) or both the electromagnetic adjustment coil (31) and the sector-type electromagnetic adjustment coil structure provided thereon are configured to cause a redistribution of magnetic flux between two or more branches of the magnetic circuit, thereby causing a change in magnetic flux density in at least two gaps (290, 291). An electromagnetic lens characterized by:

12. 2. The electromagnetic lens according to claim 1, The electromagnetic adjustment coil (31) or both the electromagnetic adjustment coil (31) and the sector-type electromagnetic adjustment coil structure provided thereon are configured to cause a modification of the magnetic flux that primarily affects one of two or more branches of the magnetic circuit, causing a change in the magnetic flux density in the corresponding gap (290). An electromagnetic lens characterized by:

13. 2. The electromagnetic lens according to claim 1, Two or more electromagnetic adjustment coils (31) are disposed at different locations associated with different components of the magnetic circuit assembly (20) configured to adjust the magnetic fields in the two gaps (290, 291) differently. An electromagnetic lens characterized by:

14. 2. The electromagnetic lens according to claim 1, The charged particle lens further includes a holder element (32) configured to hold the electromagnetic adjustment coil (31) or both the electromagnetic adjustment coil (31) and a sector-type electromagnetic adjustment coil structure provided thereon at a predetermined position between the at least two yoke elements of the yoke body. An electromagnetic lens characterized by:

15. 2. The electromagnetic lens according to claim 1, The second yoke element (251) constitutes a housing body (12) of the charged particle lens, which encloses the other components of the magnetic circuit assembly, including all other yoke elements. An electromagnetic lens characterized by:

16. 2. The electromagnetic lens according to claim 1, The at least one permanent magnet (21) has a magnetization oriented substantially radially. An electromagnetic lens characterized by:

17. 2. The electromagnetic lens according to claim 1, The at least one permanent magnet (21) segmented according to two or more layers (220) stacked along its longitudinal axis (c1); and / or divided into two or more sectors (240) arranged around its longitudinal axis (c1), Consists of at least two subelements An electromagnetic lens characterized by:

18. 18. The electromagnetic lens of claim 17, At least one temperature control device (31) is disposed between each two of the plurality of sub-elements. An electromagnetic lens characterized by:

19. 2. The electromagnetic lens according to claim 1, the charged particle lens having a generally rotationally symmetric shape along the longitudinal axis; The magnetic circuit assembly (20) comprises a plurality of components, namely: said at least one permanent magnet (21), and - the yoke body (25), and The electromagnetic adjustment coil (31) is arranged concentrically with the longitudinal axis and has a basic shape corresponding to a hollow cylinder or a hollow polygonal prism. An electromagnetic lens characterized by:

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