Adjustable permanent magnet les having shunting device

Abstract

To provide a charged particle lens which includes permanent magnets bus is capable of highly accurately adjusting optical characteristics of the lens.SOLUTION: A fine-adjustable permanent magnet lens (10) comprises a magnetic circuit assembly (20) including permanent magnets (12), a yoke body (25) and a shunting device (30) comprising a shunting element (31). The assembly surrounds a beam passage (11) extending along a longitudinal axis (cx). The shunting device is placed in the yoke body besides the permanent magnets and composed of several sector elements, comprising different high magnetically permeable materials. The permanent magnet and the yoke body form a magnetic circuit having at least two gaps (290, 291), in order to generate a magnetic field (61) reaching inwards into the beam passage. A sleeve insert (50) having electrostatic electrodes which may also generate an electric field (65) spatially overlapping the magnetic field can be inserted into the beam passage. The shunting device partially bypasses the magnetic flux of the circuit assembly and thus reduces the magnetic field to a desired value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This application claims the benefit of priority under the Paris Convention for European Patent Application No. 22172309.1, filed on May 9, 2022, the entire content of which is incorporated herein by reference and is set forth herein.

[0002] The present invention relates to a charged particle lens including a permanent magnet configured to correct a charged particle beam of a charged particle optical device designed to be used for processing purposes such as lithographic drawing including nano-pattern formation. Such a lens includes a passage for the charged particle beam along a longitudinal axis corresponding to the propagation direction of the charged particle beam itself and is usually concentrically aligned with the optical axis of the charged particle optical device in which the lens is used.

[0003] The present invention further relates to an electromagnetic lens including a charged particle lens and to a charged particle optical device including a lens of the above type.

Background Art

[0004] The applicant has realized a charged particle multi-beam device incorporating one or more lenses of the above type and has developed corresponding charged particle optical elements, pattern defining devices, and drawing methods suitable for a plurality of charged particle beams at the same time; a 50 keV electron multi-beam writer called eMET (electron Mask Exposure Tool) or MBMW (multi-beam mask writer) has been commercialized, which 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 referred to as PML2 (Projection Mask-Less Lithography), which is used for an electron beam direct writer (EBDW) applied directly to a substrate.

[0005] In particular, for maskless lithography and direct writing of substrates (e.g., wafers), increasing the current transmitted by the charged particle beam passing through a charged particle nanopatterning apparatus is necessary to improve throughput in industrial mass production; this usually comes at the cost of resolution limitations due to the interaction of Coulomb forces between charged particles, requiring corresponding compensation by reducing the magnitude of optical aberrations introduced by the apparatus through other mechanisms. For this purpose, the applicant has developed a charged particle multibeam apparatus including multiple parallel optical columns combined with a multi-column method. Each column has a reduced ("slim") cross-sectional diameter compared to earlier lithography configurations such as eMET.

[0006] Such multi-column systems (an example of which is discussed below with reference to Figure 15) enable significantly larger currents with charged particle beams while overcoming the limitations imposed by the trade-off between current and optical aberrations seen in single-column systems. This is based on the fact that the entire current supplied to the target is divided across multiple optical axes, while the resolution is limited by the magnitude of the current per optical axis. This type of single-column system is well known in the prior art, such as the applicant's US6,768,125, EP2 187 427 A1 (=US8,222,621) and EP2 363 875 A1 (=US8,378,320). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] US6,768,125 [Patent Document 2] EP2 187 427 A1 [Patent Document 3] US8,222,621 [Patent Document 4] EP2 363 875 A1 [Patent Document 5] US8,378,320 [Overview of the project] [Problems that the invention aims to solve]

[0008] A typical multi-column system includes multiple optical subcolumns, each subcolumn containing an irradiation system that supplies a broad, telecentric charged particle beam to a pattern defining system and then to a charged particle projection optical system, the charged particle projection optical system containing, for example, a number of electrostatic, magnetic, and / or electromagnetic lenses.

[0009] To use such a system as a high-throughput wafer direct writing machine, it would be necessary to arrange a considerable number of columns above a single semiconductor wafer, for example, on the order of 100 columns. However, this configuration limits the radial dimension of each column to a diameter of only a fraction of the overall width of the wafer; 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 the reduction in column diameter would correspond to extremely large Joule heat generation based on the large current required to drive the coil(s) to generate a sufficiently strong magnetic field. However, there is insufficient space for a proper temperature control system, including the high-precision sensors(s) and isotropic uniform cooling devices that would be required for conventional coil-type magnetic lenses.

[0010] The above limitations, imposed by thermal and geometric (spatial) requirements, are severe, but can be overcome by employing a magnetic lens based on a permanent magnet, together with a permeable yoke for guiding magnetic flux and thus generating a magnetic field, as in a possible embodiment of the present invention. However, such permanent magnets cannot be tuned much after manufacturing and assembly are complete, and therefore their use in magnetic lenses is limited. This represents a serious drawback to coil-type magnetic lenses, whose magnetic field can be controlled by adjusting the current flowing through the coil. In particular, given the inherent limitations on the accuracy of the target magnetic field (target magnetic field) due to manufacturing and assembly, the precision of the magnet manufacturer is crucial for the operating purposes of magnetic lenses containing such magnets; current precision limitations correspond to a deviation of approximately 1% to 5% from the target magnetic field; the magnetic field strength is on the order of 1T.

[0011] The above-mentioned deviations are due to manufacturing tolerances and statistical uncertainties, which are virtually unavoidable for manufacturing processes that have a reasonable production volume of magnetic lenses for mass production. The present invention provides a novel approach to compensate for these deviations by including an additional component that allows for tuning of the magnetic field during the assembly (manufacturing) of the above-mentioned lenses. The present invention removes the (unrealistic) precision burden (constraint) in 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. This is because the applicant's invention can compensate for deviations of the actual permanent magnet (magnetic field strength) from the desired nominal (rated) magnetic field strength, and can even tolerate larger deviations as long as the geometric parameters of the system remain within specifications.

[0012] In situ, i.e., during operation of the apparatus, tuning of permanent magnet-based charged particle lenses is typically done by using them in combination with one or more additional electrostatic lenses; that is, 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. US9,165,745 describes a permanent magnet-type electromagnetic lens combined with a coil-type magnetic lens for fine tuning. This allows for tuning of the magnetic field but has at least the above-mentioned heating and geometric (space) problems that make it unsuitable for at least some of the multiple embodiments of the present invention. Furthermore, the magnetic field of the above-mentioned prior art magnetic lenses does not adequately confine the charged particle lens itself to space, which causes serious cross-effects when a large number of lenses are juxtaposed in a multi-column system.

[0013] From the above perspective, the object or problem of the present invention is to provide a charged particle lens that includes a permanent magnet but allows for high-precision 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 shape and allows for the confinement of magnetic and electric fields within the immediate vicinity (region) of the lens itself; thus enabling a multi-column optical system with reduced crosstalk. [Means for solving the problem]

[0014] In a first aspect of the present invention, a charged particle lens is provided, configured to modify a charged particle beam in a charged particle optical system, the lens having a beam passage that extends mainly along the longitudinal axis and allows the passage of the charged particle beam. The aforementioned lens is, • At least one permanent magnet, • York body, and • At least one shunt device Including a magnetic circuit assembly, The yoke body is composed of at least two yoke elements, of which the first yoke element constitutes an inner yoke shell arranged to surround the beam passage (passage space), and the second yoke element constitutes an outer yoke shell arranged to surround the inner yoke shell, and the at least two yoke elements are arranged around the longitudinal axis and include a highly magnetic permeable material; The at least one permanent magnet is positioned between the at least two yoke elements and around the inner yoke shell, and the at least one permanent magnet comprises a permanent magnet material in which its two magnetic poles are magnetically oriented toward each of the yoke elements; In the magnetic circuit assembly, the at least one permanent magnet and the yoke body form a closed magnetic circuit, but have at least two gaps formed between corresponding axial faces of different yoke elements, configured to guide the magnetic flux density arriving from the at least one permanent magnet through the yoke body, and to induce a magnetic field inward into the beam passage through the at least two gaps, and The at least one shunt device includes at least one permeable shunt element and is positioned at a defined location between the at least two elements of the yoke body, and the at least one shunt device allows a defined (predetermined) portion of the magnetic flux to bypass at least one portion of the magnetic circuit assembly. It is characterized by (Form 1). A second aspect of the present invention provides an electromagnetic lens comprising a charged particle lens and a sleeve insert member inserted into the beam passage (passage space) along the vertical axis. In the electromagnetic lens, The sleeve insert member surrounds the beam passage having a radius smaller than the radius of the beam passage of the charged particle lens and extends along the vertical axis. The sleeve insert member includes a mount body having at least a partially conductive portion (being conductive) and at least one conductive electrode element. The at least one (conductive) electrode element is configured such that an electrical potential (with respect to a conductive part) is applied via a power source to an electrical potential for generating an electrostatic field within the beam path. (Aspect 10). According to a third aspect of the present invention, a charged particle optical device including the charged particle lens (or the electromagnetic lens of the present invention) of the present invention is provided. The charged particle optical device is configured to affect a charged particle beam of the device propagating through the lens along a longitudinal axis of the lens, and the lens is part of a particle optical system of the device (Aspect 16).

Embodiments for Carrying Out the Invention

[0015] (Aspect 1) Refer to the first aspect of the present invention above. (Aspect 2) In the charged particle lens according to Aspect 1, the charged particle lens has an overall rotationally symmetric shape along the longitudinal axis, and components of the magnetic circuit assembly, namely, · at least one permanent magnet, · a yoke body, and · at least one shunt device are arranged coaxially with the longitudinal axis and preferably have a basic shape corresponding to a hollow cylinder or a hollow polygonal prism shape. (Aspect 3) In the charged particle lens according to Aspect 1, the at least one shunt element is preferably composed of two or more layers stacked (arranged one above the other) along the longitudinal axis and / or one or more sectors arranged around the longitudinal axis. (Aspect 4) In the charged particle lens according to Aspect 1, The at least one shunt element is composed of two or more sector elements made of a magnetic permeable material, and the two or more sector elements are arranged at different azimuth positions (directions) around the vertical axis. Preferably, at least one of the two or more sector elements includes a permeable material having a permeability different from that of the other sector elements, thus enabling the magnetic lens to have a magnetic flux density that varies differently azimuthically (or directionally) (according to azimuth (or directional)), and therefore a magnetic field that varies azimuthically (or directionally) (according to azimuth (or directional)) around the vertical axis. (Form 5) In the charged particle lens described in Form 4, The at least one permanent magnet is composed of at least two sub-elements, each positioned at a different azimuth around the vertical axis. Preferably, at least one of the shunt devices(s) or at least one of the two or more sector elements is positioned between each of the at least two permanent magnet sub-elements. (Form 6) In the charged particle lens described in Form 1, Preferably, the second yoke element constitutes the housing body of the lens assembly, and the housing body surrounds (encloses) the other elements of the lens assembly, including all other yoke elements. (Form 7) In the charged particle lens described in Form 1, The at least one permanent magnet has a magnetization that is substantially oriented in the radial direction. Preferably, the at least one shunt device includes a material with high permeability at least in a direction parallel to the substantially radially oriented magnetization. (Embodiment 8) In the charged particle lens described in Embodiment 1, The aforementioned at least one permanent magnet is composed of at least two sub-elements, that is, • The data is segmented according to two or more layers stacked along the vertical axis; and / or It is preferable that the data is divided into two or more sectors arranged around the vertical axis. (Form 9) In the charged particle lens described in Form 8, Preferably, at least one shunt device is positioned between each of the at least two sub-elements. (Form 10) Refer to the second perspective of the present invention described above. (Form 11) In the electromagnetic lens described in Form 10, Preferably, the vertical axis of the sleeve insert member coincides with (overlaps with) the vertical axis of the charged particle lens. (Form 12) In the electromagnetic lens described in Form 10, The (at least one) electrode element is configured to form a particle optical lens in conjunction with the magnetic field in the beam path in at least one of the at least two gaps. Preferably, the focal length of the charged particle optical lens can be adjusted by modifying (changing) the electrical potential applied to the electrode element. (Form 13) In the electromagnetic lens described in Form 10, The inner yoke shell extends along the longitudinal axis and surrounds the sleeve insert member in the circumferential direction. Preferably, the at least two gaps of the magnetic circuit are located at either axial end of the inner yoke shell, and each gap generates a defined (predetermined) magnetic field that extends inward into the space of the beam passage, and the electrostatic field generated by at least one of the plurality of (at least one) electrode elements of the sleeve insert member is configured to at least partially overlap the magnetic field. (Form 14) In the electromagnetic lens described in Form 10, Preferably, at least one of the plurality of electrode elements (the at least one of the plurality) includes an electrostatic multipole electrode, the electrostatic multipole electrode includes a plurality of auxiliary electrodes uniformly (at regular intervals) arranged around the longitudinal axis along the circumferential direction, and the plurality of auxiliary electrodes are connectable to a multi-channel power supply unit that supplies potential to each auxiliary electrode individually. (Form 15) In the electromagnetic lens described in Form 10, The plurality of electrode elements (at least one of them) include a beam aperture element that forms a limiting aperture having a predetermined radius defined around the vertical axis. The limiting aperture is configured to limit the width of the charged particle beam propagating along the vertical axis, and Preferably, the beam aperture element is connected to a current measuring device configured to measure the amount of charged particle beam absorbed by the beam aperture element. (Mode 16) Refer to the third viewpoint of the present invention described above. (Embodiment 17) In the charged particle optical apparatus described in Embodiment 16, The apparatus is configured as a multi-column system including multiple particle optical columns. Each column is preferably configured to use its respective particle beam and includes its respective particle optics system, which includes its respective configuration (instance) of a charged particle lens or an electromagnetic lens.

[0016] The above objective is achieved by a lens configured to modify (e.g., shape, focus / defocus, or otherwise operate) the charged particle beam of a charged particle optics. The lens comprises a beam passage extending primarily along the longitudinal axis and allowing the passage of the charged particle beam, and further comprises a magnetic circuit assembly including at least one permanent magnet, a yoke body composed of at least two high-permeability elements, and at least one shunt device ((magnetic flux) shunt device).

[0017] The yoke body includes a first yoke element positioned to surround the beam passage and capable of forming an inner yoke shell, and a second yoke element positioned to surround the inner yoke shell and capable of forming an outer yoke shell (where the terms "inner" and "outer" refer to their respective relative positions within the lens assembly and along the central axis); these yoke elements are positioned around a longitudinal axis and are appropriately made from a highly permeable material such as a ferromagnetic material or ferromagnetic material.

[0018] The permanent magnet includes a permanent magnet material in which at least one permanent magnet is positioned between at least two yoke elements, i.e., around the inner yoke shell and inside the outer yoke shell, and its two magnetic poles are magnetically oriented primarily toward each yoke element.

[0019] The permanent magnet and the yoke body form a closed magnetic circuit, but have at least two gaps formed between corresponding faces of different yoke elements and opening into the beam passage (for example, at each of the axial ends, located between the (axial end) face of the inner yoke shell and the corresponding face of the outer yoke shell); thus the magnetic circuit guides the magnetic flux generated by the permanent magnet through the yoke body and induces a magnetic field into the gap(s) that also reaches into the beam passage. It is this magnetic field from the gap(s) that is used to form a magnetic lens for a charged particle beam propagating in the beam passage along the longitudinal axis. The formation of this magnetic lens typically achieves a magnetic field accuracy within a range of 1% to 5% above and below the target value.

[0020] A shunt device (at least one), which includes a highly magnetic material, is positioned at a defined location between elements of the yoke body, for example, at a suitable location between the two yoke elements, where a defined portion of the magnetic flux can be bypassed away from the gap. This reduces the magnetic field that reaches the gap and generates a magnetic lensing effect inside the charged particle beam path. The accuracy of such a shunted lens can be within 0.1% to 0.5% of the desired magnetic field, thus resulting in the formation of a magnetic lens with an efficiency almost an order of magnitude greater than that of the same magnetic lens without a shunt device, i.e., closer to the designed optical properties, such as focal length. A deviation to a larger-than-expected magnetization can be compensated to some extent by reducing the magnetic flux in the gap (i.e., the requirement for magnetization accuracy is looser at the upper end of magnetization), while the shunt device cannot increase the magnetic flux and therefore limits the manufacturing yield (of the magnetic circuit components) at the lower end of magnetization (where the requirement for magnetization accuracy is stricter).

[0021] In the technical solution that forms the basis of the present invention, the yoke elements and at least one permanent magnet together form a closed magnetic circuit having at least two gaps, optionally three or more, located beside the beam path; for these gaps act as magnetic lenses, serving to guide a defined magnetic flux density, and thus a magnetic field reaching into the beam path. At least one shunt device (in the magnetic circuit, see Figure 6) is preferably positioned parallel to the magnets and gaps and in series with at least magnetic reluctance formed by the portions of the yoke elements. It is held in a position designed to reduce the deviation of the magnetic field from the design values ​​of each lens. The shunt device includes a shunt element made of a magnetic permeable material and is associated with a holder that supports and stabilizes the shunt element at a defined position within the lens assembly. It is mounted in the space between the yoke elements, preferably near (adjacent to) at least one permanent magnet of the lens to be shunted.

[0022] Furthermore, in preferred embodiments, at least one shunt element may be advantageously composed of two or more sector elements made of a permeable material, the two or more sector elements may be positioned at different azimuth locations around the longitudinal axis. The sector elements may be made of different permeable materials; in particular, at least one of the two or more sector elements may include a permeable material having a different permeability than the permeability of the permeable materials of the other sector elements. This variant allows the magnetic lens to have a magnetic flux density that varies differently along the azimuth coordinate (i.e., at different angles), and thus has a magnetic field that varies azimuthically around the longitudinal axis. In particular, this configuration can be used to generate a magnetic field that varies azimuthically around the longitudinal axis in at least one of the above gaps, configured to act like a magnetic multipole.

[0023] Shunt elements and / or their sector elements(s) may have specific shapes and sizes that allow them to be positioned between yoke elements and reduce the magnetic flux of the magnetic circuit to a calculated value; in other words, they are configured to tune the magnetic circuit assembly by forming a bypass for some of the magnetic flux in the magnetic circuit and thus reducing some of the magnetic field of the lens. The position of the shunt elements allows for local tuning of the magnetic flux density; in fact, asymmetrical position or material properties can be used to cancel and tune the asymmetry of the magnetic circuit assembly, for example by shifting the device along the longitudinal axis. Thus, deviations from the desired nominal value in intensity and, in part, further in direction, can be reduced; thus, its specific properties according to the initial design can be achieved, otherwise it may not conform to the manufacturing process of the permanent magnet and its immanent tolerances.

[0024] The present invention enables the use of currently manufactured permanent magnets that can be incorporated into charged particle lenses by adjusting the magnetic flux using the above-described shunt device. Therefore, the magnetic field defining the lens effect at the gap position can be fine-tuned. Thus, the present invention allows for a reduction in the precision of manufacturing permanent magnet materials and elements, which clearly helps in limiting their effects. The present invention also results in a reduction of stray magnetic fields.

[0025] Furthermore, with respect to the present invention, several optional developmental forms that can be combined appropriately are conceivable, as described below.

[0026] For example, one yoke element may embody (constitute) a lens housing body that surrounds other parts (components) of a magnetic circuit, other yoke elements (multiple), and even (at least one) permanent magnet and (at least one) shunt device. Generally, several parts (components) of a magnetic circuit may be used to constitute the housing of a lens, and at least one permanent magnet and / or at least one shunt device, all of which are arranged around an inner yoke shell, and / or all yoke elements may be part of the lens housing body.

[0027] In the case of a sectorized (divided into multiple sectors) element, at least one permanent magnet may also consist of at least two sub-elements positioned at different azimuth locations around the vertical axis. This not only enhances the azimuth effect of the sectorized shunt element but also brings about a cooperative effect between the sectorized shunt element and the sectorized magnet. To further enhance and modulate this interaction, it may be even more advantageous to have one or more shunt devices positioned between each pair of the permanent magnet sub-elements; in particular, one shunt device and / or one of its sector elements may be positioned at one azimuth location between the azimuth locations of the associated permanent magnet sub-elements.

[0028] Appropriate holders are provided within the yoke body to support one or more shunt devices at their respective defined positions. Furthermore, (at least one) shunt device and / or its (at least one) shunt element may be a composite structure, for example, consisting of one or more sectors arranged around a longitudinal axis and / or segmented into two or more layers stacked along the longitudinal axis. The above sub-elements (sectors, segments and / or layers) may also be formed from varying permeable materials to form a local gradient of magnetic flux reduction.

[0029] In many typical configurations, (at least one) permanent magnets may have a substantially radially oriented magnetization; in corresponding embodiments, (at least one) shunt device may include a highly permeable material having a preferred axis of substantially radially oriented magnetization. Here, the expression “substantially radial” is used to include cases where the orientation is “operationally radial” such that the magnetic flux passing through the permanent magnet or shunt device to the yoke elements flows substantially along the radial direction (from the relatively inner yoke elements to the relatively outer yoke elements or vice versa).

[0030] In one advantageous evolutionary form, the (at least one) permanent magnet and / or the (at least one) shunt element may also consist of two or more layers stacked along the longitudinal axis; furthermore, the (at least one) permanent magnet may be embodied (constituted) of three or more sectors arranged circumferentially around the longitudinal axis, in which case, preferably, the magnet sectors are substantially wedge-shaped elements forming sectors (center or vertex) with respect to the longitudinal axis. In both cases, one or more shunt devices may be arranged between each of two sub-elements, i.e., layers or sectors.

[0031] In many embodiments, at least one shunt device may be a ring of circular or elliptical, oval, or other shapes such as a general hollow cylinder or hollow polygonal prism; the ring shape may also consist of two or more (e.g., four, six, eight) sub-elements, multiple sectors arranged circumferentially around a longitudinal axis and forming the shape, and / or multiple segments along the longitudinal axis. Shunt devices of specific shapes that fill only sectors of space within a yoke element, and thus locally deflect (change the direction of) the magnetic flux, may also be used to adjust asymmetry; such devices may also consist of multiple different materials to allow the permeability of the constructed shunt device to vary. The asymmetry with respect to the rotational symmetry of the shunt device may also be used to construct magnetic multipoles, such as assemblies in a lens, when the change in the magnetic field by the shunt device changes around a longitudinal axis. Alternatively, or in combination with this, the shunt device (or some or all of its sub-elements) may consist of two or more layers (segments) stacked along the vertical axis.

[0032] A further aspect of the present invention relates to an electromagnetic lens comprising a charged particle lens according to the present invention and a sleeve insert member inserted into a beam passage along a longitudinal axis, wherein the sleeve insert member surrounds a smaller portion of the beam passage opening but extends between its ends along the longitudinal axis; preferably overlapping with at least a gap of a yoke element. The sleeve insert member includes at least one conductive electrode element, to which an electrical potential can be applied using a power source such that each electrode element generates an electric field in the beam passage. Advantageously, the electrode elements may be configured to form a particle optical lens in combination with a magnetic field in (at least one) gap in the passage opening. The optical parameters of the particle optical lens, such as the focal length, can be further adjusted by modifying (changing) the electrical potential applied to the electrode elements.

[0033] According to one preferred geometric layout, the yoke body may extend between the two axial ends of the beam passage and thus form it; in particular, a first element, such as an inner yoke shell, may extend from the beginning to the end of the central portion of the passage, but maintain an open gap at both ends toward a second element, such as an outer yoke shell. The outer yoke shell surrounds the inner yoke shell radially and axially, preferably extending on both sides thereof; thus, the yoke elements may form a geometric structure of two hollow cylinders arranged concentrically and nested. Thus, the inner yoke shell surrounds at least one portion of the sleeve insert member; the gaps in the magnetic circuit each reach inward into the passage opening, inducing a magnetic field that overlaps with the electric field generated by the electrode elements of the sleeve insert member, thereby enabling the formation of an electromagnetic lens. Such a finely tuned electromagnetic lens can achieve an accuracy range of 1 ppm to 5 ppm with respect to the design (target) characteristics. For example, the focal length of such an electromagnetic lens can be adjusted during operation, i.e., during the time a charged particle beam is passing through it, by modifying the electrical potential applied to the electrode elements.

[0034] In many forms, the sleeve insert member may include a ceramic body in which electrodes(s) are embodied (composed) as conductive coatings having a limited shape and range.

[0035] Electrode elements can often be configured (mechanically and electrically) to form at least one single lens; furthermore, in many embodiments of the invention, at least one of the electrode elements may include an electrostatic multipole electrode comprising a plurality of auxiliary electrodes uniformly (at regular intervals) arranged circumferentially around a longitudinal axis. This allows the lens to deflect or shape a charged particle beam traversing (longitudinally) the electrode element(s), while the electrical potential applied to the auxiliary electrodes of the element may be defined to form a multipole electric field.

[0036] In many embodiments of the lens of the present invention, particularly when the lens is intended to be used in association with a pattern defining system (PD), a beam aperture element may be provided between the electrode elements, forming a limiting aperture having a radius defined around a longitudinal axis, which limits the width of the charged particle beam propagating through the passage. This limiting aperture may be used as a calibration aperture, which is operable to collect particles, including those intentionally deflected in the pattern defining system; it is intended to prevent particles from reaching a target of the charged particle beam. Furthermore, the beam aperture element may be connected to a current measuring device, for example, which may be used to measure the amount of charged particles absorbed in the beam aperture element. It is advantageous to have an electrostatic multipole electrode configured to determine the cross position of the beam with respect to the longitudinal axis by applying a plurality of different suitable electrostatic potentials to the auxiliary electrodes, and thus scanning the beam across the aperture, in front of such a beam aperture element, i.e., upstream.

[0037] Preferably, the charged particle lens may have a shape that is rotationally symmetrical overall along the longitudinal axis. In this case, the element(s) of the magnetic circuit assembly are arranged coaxially (concentrically) with respect to the longitudinal axis and preferably have a basic shape corresponding to a hollow cylinder or a hollow polygonal prism shape.

[0038] Unlike known magnetic lenses, such as those described in US9,165,745, the electromagnetic lens of the present invention has a completely closed magnetic loop (closed circuit) except for a number of "air gaps" in the housing body. These allow the magnetic field to be directed to a desired region(s) of the optical axis, thereby reducing the influence of stray magnetic fields (present in single-gap systems following Ampere's circuit law) which negatively affect the performance of electromagnetic lenses, such as those used in charged particle multi-beam nanopatterning apparatuses. Therefore, it is extremely advantageous to have (at least) two gaps in order to minimize the stray magnetic fields present in the aforementioned prior art systems. However, it will be clear that the number of gaps may be larger, such as three or four or more, depending on the specific application of the lens.

[0039] For at least several of the reasons stated above, the present invention and its application in lithography tools such as multi-column multi-beam charged particle patterning systems (for example, for direct lithography of substrates) are expected to have a significant impact on the development of high-throughput industrial processes for integrated circuits, as they provide a unique combination of magnetic, electrical, and calibration elements. The present invention significantly facilitates the layout, construction, fine-tuning, and even ultra-fine-tuning of lithography tools, particularly multi-column multi-beam mask lithography machines.

[0040] A further perspective of the present invention is directed to a charged particle optical apparatus including a charged particle lens (including an electromagnetic lens according to the present invention) configured to influence the charged particle beam of the apparatus propagating through the lens along its optical axis, wherein the lens is a magnetic lens and is part of the particle optical system of the apparatus. In particular, the apparatus may preferably be embodied (configured) as a multi-column system including a plurality of charged particle optical columns, wherein each column uses its own particle beam and includes its own optical system, which includes its own lens according to the present invention.

[0041] In the following, to further illustrate the present invention, exemplary and non-limiting embodiments or examples, as shown in the drawings, will be discussed. [Brief explanation of the drawing]

[0042] [Figure 1] An example of a charged particle lens according to the first embodiment of the present invention. Here, (A) (on the left side of the page) is a longitudinal cross-sectional view of the charged particle lens, and (B) is a plot of an example of the magnitude of the axial component of the magnetic field measured as a function of the y-coordinate of (A) at the position of the central axis, with and without a shunt device (dashed line) and with a shunt device (solid line). [Figure 2] An example of a symmetrical ring-shaped shunt device, including a shunt element and a holder, configured to shunt (displace (magnetic flux)) the magnetic lens shown in Figure 1(A); (A) is a partially cut section of the device, and (B) is a cross-sectional view illustrating how the shunt device can be mounted inside the lens of Figure 1(A). [Figure 3] An example of a form of shunt element composed of multiple stacked layers. [Figure 4] An example of a form of shunt element composed of multiple sectors. [Figure 5] An example of a form of shunt element composed of multiple sectors containing materials with varying (different) permeability, which allows the shunt element to have asymmetric properties with respect to the central axis. [Figure 6] Three examples of schematic magnetic circuit diagrams according to each embodiment of the present invention; (A) and (B) show examples of symmetrically shunted magnetic circuits, and (C) shows an example of an asymmetrically shunted magnetic circuit. [Figure 7]An example of a charged particle lens according to another embodiment of the present invention. The lens has a shunt device arranged asymmetrically with respect to its y-coordinate. Here, (A) (on the left side of the page) is a longitudinal section of the charged particle lens, and (B) is a plot of an example of the magnitude of the axial component of the magnetic field measured as a function of the y-coordinate of (A) at the position of the central axis, in the absence of a shunt device (dashed line, 62), with a symmetric shunt device (solid line, 61), and with an asymmetric shunt device (dotted line, 63). [Figure 8] A perspective view (A) and a longitudinal section (B) of an example of a permanent magnet composed of multiple ring elements having radial magnetization. [Figure 9] Cross-sectional views of various forms of permanent magnets. Some of these ((B) to (D)) are sectorized (divided into multiple sectors) preferred magnetization variations. [Figure 10] An example of a charged particle lens according to a further embodiment of the present invention, including a sleeve insert member. (A) (on the left side of the page) is a longitudinal section of the charged particle lens and the electrical sleeve insert member located inside it, which constitutes an electrostatic lens system; (B) is a plot of an example of the magnitudes of the axial components of the magnetic field (solid line) and electric field (dashed line) of the shunted magnetic lens, measured as a function of the y-coordinate of (A) at the position of the central axis. [Figure 11] A schematic overview of an example of a voltage supply device and its elements connected to a sleeve insert member in one embodiment of the lens shown in Figure 10(A). [Figure 12] A cross-sectional view of an example of a multipole electrode with eight auxiliary electrodes. [Figure 13] A detailed enlarged view of the calibration aperture and preceding multipole as elements of a sleeve insert member in an example of an electromagnetic lens according to one embodiment of the present invention. [Figure 14] A longitudinal cross-sectional view of an example of a slim column type drawing machine tool incorporating an example of the charged particle lens of the present invention. [Figure 15]An example of a multi-column lithography tool incorporating multiple lens configurations (instances) of the present invention. (A) is a longitudinal cross-sectional view of the multi-column lithography tool; (B) is a detailed view of a portion including the lens and an example of a multi-lens holder device. [Examples]

[0043] The detailed discussion of the exemplary embodiments (multiple examples) of the Invention given below discloses the basic idea, embodiment, and further advantageous developments of the Invention. It will be apparent to those skilled in the art that some or all of the embodiments (multiple examples) discussed herein may be arbitrarily combined as suitable for a particular application of the Invention. Throughout this disclosure, terms such as “advantageous,” “exemplary,” “typical,” “preferred,” or “preferred” describe elements or dimensions that are particularly suitable (but not essential) for the Invention or one embodiment thereof, and can be modified unless expressly required, if deemed suitable by those skilled in the art. It goes without saying that the Invention is not limited to the exemplary embodiments (multiple examples) discussed below, which are given for the purpose of describing the Invention and merely present preferred embodiments (multiple examples) of the Invention. Within the scope of this disclosure, terms relating to vertical directions, such as “up” or “down,” should be understood in relation to the direction of a particle beam traversing an electromagnetic lens, which is considered to travel downward (“perpendicularly”) along the central axis (or longitudinal axis). This longitudinal axis is generally identified (considered equivalent) by the Z direction intersecting the X and Y directions.

[0044] Charged particle lens

[0045] Figure 1(A) shows a longitudinal section of an example of a charged particle lens 10 according to a first embodiment of the present invention, i.e., along a section passing through its central axis cx. For better clarity, the components are not shown to their dimensions. The lens may be used to embody the lens 10 of the drawing machine tool 1 in Figure 14 or the multi-column drawing machine tool 40 in Figure 15 (see below), in which case it is used as an objective lens, but it will be apparent that it is also suitable for use in many other particle optics that can embody single-column or multi-column architectures, such as those disclosed in the applicant's US9,443,699 and US9,495,499. The disclosures in these documents are incorporated herein by reference.

[0046] 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, the magnetic circuit assembly 20 including a yoke body 25 having at least one permanent magnet 210, 211, at least two gaps 290, 291, and a shunt device 30. The above magnets typically have a residual magnetism of approximately 1T, The yoke body 25 is made from a permanent magnet material having magnetic flux represented by the symbol TIFF2023166336000002.tif6150; 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 (both) are made from a high-permeability material; the yoke elements(plural) 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 into the beam passage 11; and finally, the shunt device 30 includes at least one shunt element 31 made of a high-permeability material and a dedicated holder 32 configured to position the shunt element in the space between these yoke elements. The defined (predetermined) part of TIFF2023166336000003.tif6150 is the flux (magnetic flux). TIFF2023166336000004.tif6150 This allows for bypassing the magnetic lensing effect. Depending on the strength of the magnetic lensing effect, the charged particle beam 100 may also form a crossover xo within the beam passage 11, i.e., the beam achieves its minimum width while traversing the central axis cx; the dotted line symbolically represents the envelope of the charged particle beam as it propagates through the lens when arranged in an exemplary particle beam exposure system (such as the drawing machine tool 1 in Figure 14 or the multi-column drawing machine tool 40 in Figure 15).

[0047] 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 smaller than the overall height h1; this allows for a design in which the outermost yoke element 251 (also called the outer yoke shell) serves as a housing and shield body for the lens assembly; an outer radius r1 of approximately 10 mm to 20 mm, which allows for placement in the multi-column drawing machine tool 40 shown in Figure 15; and an aperture radius r2 that is wide enough to allow for a charged particle beam passage of approximately 0.1 mm to 5 mm. Furthermore, additional insert members may be permitted (see Figure 10 below). These magnet, gap, and shunt devices typically have a thickness of approximately 1 mm to 5 mm, and the yoke elements may have radial thicknesses of approximately the same dimensions. The size of each element(s) is selected to be appropriate for the respective application and charged particle apparatus, but in the illustrated example, the geometric dimensions are typically on the order of a few millimeters.

[0048] The charged particle lens 10 is typically positioned in the particle beam exposure system such that its central axis cx coincides with the optical axis c5 of the exposure system (see Figure 14); however, as those skilled in the art will see, other relative positions are also selectable depending on the application of the charged particle lens of the present invention.

[0049] Magnetic circuit and shunt device

[0050] In accordance with the present invention, the magnetic circuit assembly 20 and the corresponding magnetic lens include at least one shunt device 30, the shunt device 30 including a shunt element 31 disposed in a dedicated holder 32 (Figure 2) within the assembly. The shunt device has an initial magnetic flux The defined portion of TIFF2023166336000005.tif6150 TIFF2023166336000006.tif6150 allows bypassing gaps 290 and 291, enabling a reduction in magnetic flux density in these gaps. The (one) shunt element is made of a highly permeable material and is typically of the same order of magnitude as the yoke elements 250 and 251 in the immediate vicinity of the (shunt) device. The shunt device according to the present invention allows a reduction in the magnetic field in these gaps. The effect (result) is plotted in Figure 1(B), which shows the axial component of the magnetic field Bz along the central axis cx of the magnetic lens: the solid line 61 is for the shunted element (lens) and the dashed line 62 is for a lens of the same dimensions but not shunted. According to this, it can be seen that the magnetic field is confined to the region of the gap, where the magnetic lens is formed, along with a reduction in the maximum magnetic field strength. Conventional permanent magnet lenses can achieve an accuracy within 1% to 5% of the target magnetic field strength due to the manufacturing range (conditions) of the permanent magnets arranged in such a system. By using a shunt device according to the present invention, this range can be reduced to an accuracy within 0.1% to 0.5% of the target effect, thereby providing a deviation from the desired magnetic field that is less than an order of magnitude smaller, and therefore significantly better performance.

[0051] Figure 2 shows an example of an exemplary form of a shunt device 30. The shunt device 30 may include a shunt element 31 positioned in a holder 32, the shunt element 31 and the holder 32 being ring-shaped elements (see Figure 2(A)), having a common central axis c2, which preferably coincides with the central axis cx of the lens assembly. The shunt device is typically positioned immediately adjacent to two or more permanent magnets 210, 211 and between yoke elements 250, 251 (see Figure 2(B)); however, since the position of the shunt device is rather encapsulated (sealed), it may need to be installed during lens assembly; nevertheless, the shunt device can also be added after the initial assembly if a suitable technical solution, such as partial disassembly, is used, or if the device consists of interchangeable modules (see below) inside the lens.

[0052] Referring to Figures 3 to 5, in some embodiments of the present invention, the shunt element 31 of the shunt device 30 may consist of a plurality of sub-elements 330, 340, 350 arranged along or around a common axis c2 that can coincide with (overlap with), for example, the central axis cx of the complete lens assembly. These sub-elements may be a plurality of layers 330 (Figure 3), in which case the shunt element 31 is constructed as a laminate. Alternatively, these sub-elements may be a plurality of sectors 340 (Figure 4), in which case the shunt element is constructed as a composite ring-shaped element. The sectors 350 to 354 may also consist of different materials having different high permeability (Figure 5); this allows for a shunt element with varying magnetoresistance, and therefore local variations in magnetic flux density in the assembled shunt element 31. Such a change in the permeability of the shunt element can be associated with magnetic multipoles in the magnetic lens assembly, which can be used to intentionally introduce such azimuth dependence; this can be used, for example, to counteract permanent magnets that give multipole-like characteristics. On the other hand, for permeability of a much smaller region, for example If we have TIFF2023166336000007.tif6150, the shunt elements can be described as "sparse". Generally, these sectors do not need to be uniformly distributed (placed at regular intervals) around the central axis c2.

[0053] The magnetic circuit assembly can be represented by magnetic circuit diagrams (Figures 6(A) to (C)), which provide insight into a generalized case of the present invention, namely, a rotationally symmetric system in which each sub-component of the lens has essentially constant properties, such as element thickness and magnetic properties (permeability). In that case, length TIFF2023166336000008.tif6150, main cross section TIFF2023166336000009.tif6150 and constant permeability A certain element (subscript) that has TIFF2023166336000010.tif6150 Magnetoresistance of TIFF2023166336000011.tif6150) TIFF2023166336000012.tif6150 is, It can be calculated as TIFF2023166336000013.tif11150. Here, TIFF2023166336000014.tif6150 is the permeability of vacuum.

[0054] A permanent magnet has a constant magnetic flux TIFF2023166336000015.tif6150 can be introduced, but the element Magnetic flux passing through TIFF2023166336000016.tif6150 TIFF2023166336000017.tif6150 is This can be derived from TIFF2023166336000018.tif10150. Here, TIFF2023166336000019.tif6150 is magnetic flux This is the total (magnetic) resistance that TIFF2023166336000020.tif6150 will experience.

[0055] Furthermore, the above elements Magnetic field within TIFF2023166336000021.tif6150 TIFF2023166336000022.tif6150 is defined as magnetic flux density, It can be calculated as TIFF2023166336000023.tif10150. Here, if the material is "vacuum", then ultimately, the above equation(s) are combined to form a vacuum. Magnetic field within TIFF2023166336000024.tif6150 It is possible to provide TIFF2023166336000025.tif10150.

[0056] Therefore, for vacuum gaps 290 and 291, the magnetic field strength TIFF2023166336000026.tif6150 is the total (magnetic) resistance of the assembly. It can be derived that this can be reduced by increasing TIFF2023166336000027.tif6150, which is the purpose of the shunt device 30—however, it should be noted that the assumptions and simplifications made to derive this simplified equation will limit the precision (accuracy), but rather give an estimate of the dependencies.

[0057] Three exemplary cases of possible shunting methods are illustrated, but it should be apparent to those skilled in the art that other relative arrangements may also be selected depending on the application of the charged particle lens according to the present invention. In Figures 6(A) to (C), for better clarity and readability, the components of the magnetic circuit are indicated by the same reference numerals as for the corresponding components in Figure 1(A) (for example, 250 and 251 refer to yoke elements), and below, magnetic flux TIFF2023166336000028.tif6150 and magnetoresistance Magnetic quantities such as TIFF2023166336000029.tif6150 are indicated using the reference numerals in the drawings as subscripts. Furthermore, the yoke elements 250 and 251 are divided into four parts (i.e., 250a-250d and 251a-251d) respectively, indicated by additional subscripts a-d in the magnetic circuits of Figures 6(A)-(C); furthermore, the vacuum gaps 290 and 291 correspond to magnetoresistances represented by the zigzag resistance symbol.

[0058] The exemplary magnetic circuit 20a shown in Figure 6(A) has approximately the same initial magnetic flux (i.e.) TIFF2023166336000030.tif6150 and Two permanent magnets 210 and 211 having TIFF2023166336000031.tif6150), and nearly the same cross-section A and permeability μ (i.e.) TIFF2023166336000032.tif6150 and Two yoke elements 250 and 251, of approximately the same size (i.e., TIFF2023166336000033.tif6150) TIFF2023166336000034.tif6150 and TIFF2023166336000035.tif6150 This result TIFF2023166336000036.tif6150 is obtained) with two gaps 290, 291 and magnetoresistance R 31 The shunt device 30 includes one shunt element 31 having a shunt element 31 having a shunt element 31 having a shunt element 31 having a shunt element 30 having a shunt element 30 having a shunt element 30 having a shunt element 30 having a shunt element 30 having a shunt element 31 TIFF2023166336000037.tif6150 and similarly TIFF2023166336000038.tif6150, TIFF2023166336000039.tif6150 and TIFF2023166336000040.tif6150 and The value of TIFF2023166336000041.tif6150 is given. Here, the summation (Σ) is This concerns TIFF2023166336000042.tif6150. The estimated value of the magnetic field in a vacuum gap of 290 is... It can be obtained in TIFF2023166336000043.tif10150. Here, TIFF2023166336000044.tif6150, and the primary permeability. TIFF2023166336000045.tif6150, cross-section TIFF2023166336000046.tif6150 and length The magnetoresistive resistance of the shunt device 30 having TIFF2023166336000047.tif6150 TIFF2023166336000048.tif6150 is, It will be calculated as TIFF2023166336000049.tif11150.

[0059] In the above, the symbol TIFF2023166336000050.tif6150 is intended to indicate equality within a given tolerance range, such as approximately 2% or 5%.

[0060] In many forms, symmetrical lens assemblies are particularly important. Each magnetic field in a radially symmetrical magnetic lens structure contains both an axial and a radial component, i.e., TIFF2023166336000051.tif6150; in relation to this, the radial component TIFF2023166336000052.tif6150 is of little importance, and as a result, the magnetic field (for example) Axial component of TIFF2023166336000053.tif6150) TIFF2023166336000054.tif6150 is used for the lens effect. The strength of the axial component of the magnetic field at the position of the central axis cx is shown as a function of the y-coordinate in Figure 1(B) (solid line); axial magnetic field Typical peak values ​​for TIFF2023166336000055.tif6150 are on the order of 0.1T in applications where the charged particles are electrons. As previously described, the magnetic circuit will generate two regions near gaps 290 and 291 with (relatively) high magnetic field strengths, which act as two consecutive magnetic lenses with well-defined focal lengths and optical aberrations within the beam path 11. The magnetic coupling of the two lenses via a common yoke body 25 strongly reduces the effect of stray magnetic fields in any other region, but in other respects would inevitably be associated with the permanent magnets in particle lenses of a conventional layout.

[0061] In another exemplary embodiment, as shown in Figure 6(B), the magnetic circuit 20b includes one permanent magnet 210, two yoke elements 250, 251, two gaps 290, 291, and two shunt devices including two shunt elements 31a, 31b. The (magnetic) resistance of each shunt element 31a, 31b is, in this case as well, It can be calculated as TIFF2023166336000056.tif11150 (where x represents a or b). And this assembly, in this case as well, TIFF2023166336000057.tif6150 and furthermore, TIFF2023166336000058.tif6150, TIFF2023166336000059.tif6150 and lastly TIFF2023166336000060.tif6150 and If the filename is TIFF2023166336000061.tif6150, then symmetry is possible. Here, the summation (Σ) is This pertains to TIFF2023166336000062.tif6150; in contrast, for example, if the (magnetic) resistances (multiple) of the shunt device (elements) are not equal, i.e. In the case of TIFF2023166336000063.tif6150, it is asymmetrical. Furthermore, if the magnetic field at gaps 290 and 219 is not symmetrically reduced by the shunt device, an asymmetrically shunted lens will be obtained (see below).

[0062] Furthermore, in another exemplary embodiment shown in Figure 6(C), such an asymmetrical effect is achieved with an asymmetrical permanent magnet, i.e. It can be used for the adjustment of TIFF2023166336000064.tif6150. For example, at least one shunt device 30 is mainly Regarding TIFF2023166336000065.tif6150 (i.e., the magnetic flux passing through a gap of 290): This allows bypassing TIFF2023166336000066.tif6150, It may be positioned in the magnetic circuit assembly 20c in a location that has a limited effect on TIFF2023166336000067.tif6150 (i.e., the magnetic flux of the other gap 291).

[0063] In some embodiments of the present invention, it may be useful to have an asymmetric position of the shunt device with respect to the longitudinal symmetry of the magnetic lens (see Figure 7(A)). The advantages of an asymmetric shunt layout will be illustrated using the circuit diagram 20c in Figure 6(C). The shunt device 30 includes one shunt element 31 that is not positioned symmetrically with respect to the longitudinal symmetry of the lens, but is positioned near at least one of the two gaps (for example, near gap 290). In this case, the shunt (action) will result in a greater reduction in the magnetic field strength at the gap 290. This is further illustrated in the graph of Figure 7(B), which shows the effect (result) as the axial component of the magnetic field along the central axis cx of the magnetic lens device in Figure 7(A); that is, the solid line 61 is for a symmetrically shunted lens (corresponding to Figure 1(B)), the dashed line 62 is for a lens of the same dimensions but not shunted (unshunted), and the dotted line 63 is for an asymmetrically shunted lens of this embodiment of the present invention. It can be seen that the reduction in magnetic field strength is greater in the gap closer to the shunt device, and that the magnetic field is also reduced in the other gap, but to a smaller degree. This asymmetric shunt (action) can be used to induce (cause) an effect of localizing the shunt (action) to the intended gap 290, and / or to counteract the unexpected inherent asymmetry of the permanent magnet(s) used, for example, when the upper magnet 210 has a greater magnetization, i.e., a much larger deviation from the target value, and as a result generates a larger magnetic field than intended if the upper gap 290 were not corrected by the shunt (action) according to the present invention.

[0064] The multiple permanent magnets 210, 211 can be used in many preferred forms. For example, they can preferably be arranged in a stacked (vertically aligned) manner along the longitudinal axis of the system, in which case, in some of these forms, a multiple shunt device 30 on several holder devices may be used, and such device(s) may be positioned between the multiple permanent magnets(s) along the longitudinal axis of the lens (Figures 1(A), 10(A)).

[0065] Permanent magnet

[0066] The permanent magnets 210 and 211 function as sources of magnetic flux Φ in the magnetic circuit realized in the magnetic circuit assembly 20.

[0067] Figure 8 shows a preferred embodiment of a permanent magnet 21 suitable for use as a component of a lens magnetic circuit assembly according to the present invention (for example, as one of the permanent magnets 210, 211 in Figure 1(A)). The magnet has a principal radial magnetization with respect to a rotationally symmetric magnet. In Figure 8, (A) is a schematic perspective view and (B) is a schematic cross-sectional view of the magnet 21 along the longitudinal axis c1.

[0068] In many forms, as can be seen in Figures 9(A) to (D), it may be useful for such a magnet to be composed of multiple sector sections. Figures 9(A) to (D) show four exemplary variations of a ring-shaped magnet 21 having net radial magnetization in their respective schematic cross-sectional views. Note that the components of the ring-shaped magnet are shown exploded in Figures 9(B) to (D) for better clarity. This radial magnetization direction also provides preferred positions for the yoke elements, i.e., inside and outside of such a ring-shaped magnet, where magnetic flux is drawn from either pole of the magnet and directed towards the designed (intended) positions of the gaps 290, 291 between the yoke elements (see Figure 1(A)). Each of the magnetic elements will have a magnetization that is primarily oriented radially, as indicated by the dashed arrows in Figures 9(A) to (D). For example, the "north" pole N is formed toward the internal space of the ring-shaped magnet, while the outside (of the ring-shaped magnet) has the "south" pole S of the magnetization. Permanent magnet elements with radial magnetization as shown are available on the market and are made of ferromagnetic materials such as sintered NdFeB, SmCo5, or ferrite. The magnetic elements 240, 241, and 242 of the composite magnet in Figures 9(B) to (D) are joined by adhesive, fastening, or other suitable means. The number of magnetic elements forming each ring-shaped magnet can be any number, for example, one, two, three, four, six, or seven or more, depending on the dimensions of the composite element (especially the height and radius) and the desired dimensions of the permanent magnet 21.

[0069] Furthermore, referring again to Figure 8, in many forms the permanent magnet 21 is embodied (constituted) as a ring-shaped component and may include multiple layers of ring-shaped segment magnets 220 stacked along a common vertical axis c1. In such segment magnets, each layer or each segment comprises the total magnetic flux of the n-layer magnet. Part of TIFF2023166336000068.tif11150 This creates the file TIFF2023166336000069.tif16153.

[0070] Housing body

[0071] In many configurations, the yoke body 25 also functions as the housing 12 for the lens 10. The yoke body consists of an inner yoke element 250 and an outer yoke element 251, the inner yoke element often and typically embodied as a hollow cylinder having an aperture radius r2 and a length h2 sufficient to exceed at least the height of the stacked permanent magnets and shunt device; the outer yoke element 251 may also be embodied as having a cylindrical symmetrical shape with a height h1 having an aperture radius r2 and an outer radius r1 with a width sufficient to cover the thickness of each yoke element and the thickness of the magnets disposed between the yoke elements. The outer yoke may advantageously have a double "U" shaped longitudinal section (Figure 1(A)); in other words, the outer yoke includes a central body portion formed as a hollow cylinder which may be concentric with the hollow cylinder of the inner yoke element, and further has two disc-shaped end portions with a central hole. Therefore, the hollow spaces of the yoke elements surround a beam passage 11 with radius r2 and height h1 along the longitudinal axis cx. Gaps 290 and 291 of the magnetic circuit are provided between the axial outer end faces of the inner yoke elements and the corresponding axial inner surfaces of the outer yoke elements, which represent 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 several millimeters, and the height of the assembly is on the order of tens of millimeters. The inner and outer yoke elements that form the housing body of the lens can enhance and focus the magnetic flux generated by the magnet due to their shape. The outermost yoke elements also function as shields against magnetic flux in the radial and axial directions, as their spatial shape and material will accumulate magnetic flux within the dimensions of radius r1 and height h1.

[0072] Electrical inlay (insert material)

[0073] In accordance with a further view of the present invention as shown in Figure 10, the charged particle lens 10 may conveniently include a sleeve insert member or inlay 50 (Figure 10(A)) inserted into the beam passage 11 along the optical axis cx. Accordingly, the physical dimensions of the inlay are appropriately selected for the dimensions discussed above, such as within the radius r2 and height h1 of the lens. The inlay may include a plurality of beam control elements 52-54, each containing one or more electrically active elements that are employed to generate an adjustable electric field 65 (dashed line in Figure 10(B)) that overlaps with the shunted magnetic field 61 (solid line in Figure 10(B)) in the beam passage. The axial component of the electric field (i.e., along the longitudinal direction) E Z The strength is 10 5 It will likely have typical peak values ​​on the order of V / m.

[0074] In many forms of the inlay, the beam control elements 52-54 are generally ring-shaped components that serve as electrically active elements, arranged to stack along the central axis c3, with their geometric axes oriented concentrically and parallel to the central axis cx of the lens. In many forms of the present invention, it is useful for all control elements to have a common inner radius r2; thus, these define passage holes 55 that traverse the lens and serve as channels for the charged particle beam 100 during operation of the charged particle lens. Furthermore, it may also be useful to insert smaller apertures 54 (see below) for beam calibration.

[0075] In the configuration shown in Figure 10(A), the beam control element comprises two Einzel lenses and two multipole electrodes 53a, 53b—all made of conductive material. For example, each multipole electrode can be implemented as a composite metal ring consisting of multiple sections with equal arc lengths, for example, four, six, or eight sections (see Figure 12) without loss of generality; their (radial) thickness is typically less than 2 mm, and their lengths are 5 mm to 20 mm. Furthermore, preferably, a conductive ring-shaped aperture 54 is positioned between the two multipole electrodes 53a, 53b; this component is referred to here as the "calibration aperture". The electrically active elements may preferably be connected to their own power supply units 722a, 722b, 723a, 723b as shown in Figure 11, so that their electrical potentials can be adjusted individually; in one variation, the power supplies may be combined in a common multi-channel power supply unit 70 that provides individual supply voltages. The calibration aperture may be controlled by the power supply unit 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 referred to as field (electric field) termination caps 51a, whose electrical potentials represent a “local earth” or reference point. The field termination caps serve to restrict (confine) the electric field to the passage space of the inlay; thus, the field termination caps provide a clearly defined “field (electric field) boundary” of the inlay relative to surrounding components (such as other particle optical columns 400, see Figure 15). A space on the inlay mounting body 51 between the field termination cap and other electrical components can also be electrically insulating, which is embodied (constituted) by, for example, a vacuum or by a filler material using a non-conductive, preferably voltage-resistant, material such as ceramics.

[0076] In many embodiments of the present invention, various elements 52-54 of the inlay 50 are supported and held together by a hollow cylindrical mount body 51 (e.g., with an inner radius r3, an outer radius r2, and a height h1), which can generally be made of an electrically insulating material such as ceramic or plastic; however, at least the portion 51a facing the charged particle beam may be covered with a conductive material and connected to a "drain" to avoid charging up. The electrode elements may be embodied (configured), for example, as individual ring-shaped elements 52a, 52b, 53a, 53b, 54 coupled and held together within the body, or as a plurality of conductive coatings 51a formed on the inner surface of the ring body, each having a limited shape and area (region).

[0077] 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 magnet and shunt device, and subject to assembly precision), to reach an accuracy of 1 ppm to 5 ppm above or below the target value—thus enabling "ultra-high precision" tuning. Some embodiments of the present invention may also include built-in corrective means that can be used to overcome limitations, for example, related to the aging effect of the magnet, since the electric field can be adjusted and controlled with ppm (parts per million) regime precision without resolution during use of the lens, i.e., "in situ tuning" is possible. 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 with respect to optical properties such as aberrations, image plane, etc.

[0078] Figure 12 shows a cross-section of an example of a multipole electrode inlay. The multipole electrode includes multiple rods (or curved strip members) 530, each of which can be controlled by its own external power supply unit 70 with an individual electrical potential. Furthermore, a global offset voltage may be applied to cause them to behave (operate) as additional electrostatic lenses. By applying different voltages to the individual rods, various field (electric field) configurations of bipolar, quadrupole, or higher-order electrostatic fields can be realized for the purpose of shaping particle beams intersecting at corresponding transversal sections of the optical axis. In a typical application in light of the embodiment in Figure 10, the voltages applied to the rods are typically on the order of tens of volts. Such beam shaping can be used to compensate for errors resulting from 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, the beam position relative to the optical axis c3 can be corrected, but its direction(s) in the plane defined by the X and Y axes (Figure 12) can be arbitrary, as long as at least four different voltages, namely +V1 (the rod (linearly) hatched on the right side of the paper), -V1 (the rod (linearly) hatched on the left side of the paper), +V2 (the rod (grid-like) hatched on the upper side of the paper), and -V2 (the rod (grid-like) hatched on the lower side of the paper), are applied to these rods. Furthermore, when a multipole is used as a quadrupole or a higher-order multipole, astigmatism or other higher-order distortions can be compensated for by the multipole by applying appropriate voltages to the individual rods in the same manner as in the dipole case.

[0079] It should be noted that any multipole electrode can be used, depending on the application, as a (quasi)static element or as a dynamic element, i.e., an element with a time-varying voltage. Those skilled in the art will understand that the above uses of beam control elements are described as illustrative applications and not as limitations on the functions achievable by the present invention.

[0080] Referring to Figures 11 and 13, as previously described, in some embodiments of the present invention, the inlay 50 may include a passive element 54 referred to as a "calibration aperture," which acts as a stop element for deflecting (removing) the divergent portion of the particle beam 120. Figure 13 shows an enlarged and detailed longitudinal section of an example of a calibration aperture. The calibration aperture includes a body 540 that surrounds a calibration bore 541, which is an aperture having a radius r4 along axis c3. The aperture has the function of limiting the size of the beam 100 traversing the charged particle lens by absorbing the portion of the beam 120 traveling outside the aperture and allowing only the portion of the beam 110 inside the aperture to pass through. In a preferred embodiment of the present invention, one of the preceding (upstream) inlay elements, for example, a multipole electrode 53a, can change the lateral position of the beam with respect to the longitudinal axis by changing the voltage applied to a selected electrode of the multiple electrode that forms an electric dipole field, for example. The multipole can also be used for beam alignment. The charged particle lens 10 is advantageously configured to form a crossover cx[xo] in or near the longitudinal portion of the calibration aperture 54 (e.g., 10 mm or less). As a result, the beam diameter is smallest near the aperture.

[0081] In many embodiments of the present invention, particularly in particle beam apparatus used as a multi-beam lithography tool, such as a single-column tool 1 or a multi-column tool 40 (see below for the latter), a charged particle beam is divided into a plurality of beamlets that can selectively pass through a pattern defining system 4, 43 without additional lateral deviation e or f (Figure 14), introduced by the pattern defining system. Such deviations are introduced to prevent a given beamlet(s) from reaching a target, and thus to define a discrete lithography pattern. The deflected beamlet does not pass through the calibration bore 541, but reaches the area of ​​the main body 540 of the "calibration aperture" to the side of (outside) the calibration bore 541, where it is absorbed; the absorption of beam 120 will cause an electric charge-up in the components, which can be removed, or drained off, by an electrical connection of the beam aperture to a measuring device 714 that allows monitoring of the amount of beam being absorbed (Figure 11).

[0082] Lithography device

[0083] Figure 14 is a schematic longitudinal cross-sectional view of an example of a single-column lithography 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 lithography tool uses a charged particle beam which may be electrons or ions (e.g., positively charged ions). The lithography tool 1 includes a vacuum housing 480 for a multi-column charged particle optical system and a base member 470 on which the multi-column charged particle optical system is mounted. On top of an XY stage 460, for example, a laser interferometer-controlled air-bearing vacuum stage, a target 450, preferably a mask for lithography purposes or a silicon wafer in the case of a direct lithography tool, is mounted using a suitable operating system. The target, which includes, for example, a resist layer, can be exposed by the charged particle beam of the lithography machine.

[0084] This form of single-column optical system preferably includes a central axis c5, an illumination optical system 3 including a charged particle source 7, a capacitor 8 that supplies a wide, telecentric charged particle beam ib to a pattern defining system 4 (where the pattern defining system 4 is adapted to allow the beam to pass through only a plurality of apertures, which define the shape of the sub-beams ("beamlets") that pass through the apertures (beam shaping devices)), and a charged particle projection optical system 5 that typically reduces and further energizes the beam (the projection optical system 5 consists of a plurality of successively arranged charged particle lenses, which preferably include electrostatic and / or magnetic lenses, and possibly other particle light devices). In the form shown in Figure 14, the projection optical system includes, for example, a first charged particle lens 9, such as an electrostatic immersion lens, while a second lens 10, which is located downstream of the first lens, is embodied (configured) using a charged particle lens according to one embodiment of the present invention (e.g., Figure 10(A)). Inside the charged particle lens 10, a "calibration aperture" 54 is embodied (configured) as symbolically shown; as described above, a portion f of the beam deflected by the pattern defining device 4 is absorbed, while another portion e crosses the optical column without obstruction, exposing the pattern to the target 450.

[0085] The pattern defining device 4 has the function of forming multiple so-called beamlets from a particle beam, which contain information about the pattern to be transferred to the target. The structure, operation, and data processing of the pattern defining device 4 and its control device 404 are disclosed in the applicant's US9,443,699 and US9,495,499, and the contents of these documents are incorporated herein by reference.

[0086] Figures 15(A) and (B) show an example of a multi-column lithography tool 40. The tool 40 includes, in each column, a configuration (instance) of an exemplary embodiment of the lens of the present invention; for example, a charged particle lens according to an embodiment of the present invention as the objective lens in the tool. The lithography tool uses multiple charged particle beams, which may be electrons or ions (e.g., positively charged ions). As can be seen in Figure 15(A), which shows a schematic longitudinal section of the multi-column lithography tool 40, the lithography tool 40 includes a vacuum housing 48 for the multi-column charged particle optics and a base member 47 on which the multi-column charged particle optics are mounted. On top of the base of the XY stage 46, for example, a laser interferometer-controlled air-bearing vacuum stage, a target 45 is mounted using a suitable operating system, preferably a mask for lithography purposes or a silicon wafer in the case of a direct lithography tool. The target, which may include, for example, a resist layer, can be exposed by the charged particle beam of the lithography machine.

[0087] This form of multi-column optical system includes a plurality of sub-columns 400 (the number of columns shown in the figure is reduced in the diagram for better clarity and represents a much larger number of columns present in a multi-column apparatus in actual implementation). Preferably, the sub-columns(s) have the same configuration and are arranged so that their axes(s) c5 are parallel to each other. Each sub-column includes a charged particle source 41 and an illumination system 42 that supplies a wide, telecentric charged particle beam to a pattern defining system 43 (where the pattern defining system 43 is adapted to allow the beam to pass through only a plurality of apertures, which define the shape of the sub-beams ("beamlets") that pass through the apertures (beam shaping devices)), and a charged particle projection optical system 44 that typically reduces and further energizes the beam (the projection optical system 44 consists of a plurality of successively arranged charged particle lenses, which preferably include electrostatic and / or magnetic lenses, and possibly other particle light devices). In the embodiment shown in Figure 15, the projection optical system includes, for example, a first charged particle lens 44a, such as an electrostatic immersion lens, while a second lens 10, which is located downstream of the first lens, is embodied (configured) using a charged particle lens according to one embodiment of the present invention (e.g., Figure 1(A)).

[0088] Figure 15(B) shows in detail an example of lenses 10 used as second lenses and an example of their support elements. Each second lens 10 of the subcolumns is preferably mounted on a reference plate 49 which is attached to a column base plate 47 or a specific flange 48 of the vacuum chamber by appropriate fastening means 49b. The reference plate 49 is manufactured from a suitable base material having 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 high thermal conductivity, and may be appropriately coated with a conductive coating (film) at least on its relevant parts to avoid charging (by allowing static charge to leach out). Furthermore, the reference plate 49 may include apertures 49a that overlap (match) the beam passages 11 of the lenses 10 of each subcolumn.

[0089] All or part of the above embodiments may be described as follows, but are not limited to them. [Note 1] A charged particle lens configured to modify the charged particle beam of a charged particle optical system. The lens is provided with a beam passage that extends mainly along the vertical axis and allows the passage of a charged particle beam; The aforementioned lens is, • At least one permanent magnet, • York body, and • At least one shunt device Includes a magnetic circuit assembly; The yoke body is composed of at least two yoke elements, of which the first yoke element constitutes an inner yoke shell arranged to surround the beam passage (passage space), and the second yoke element constitutes an outer yoke shell arranged to surround the inner yoke shell, and the at least two yoke elements are arranged around the longitudinal axis and include a highly permeable magnetic material; The at least one permanent magnet is positioned between the at least two yoke elements and around the inner yoke shell, and the at least one permanent magnet comprises a permanent magnet material in which its two magnetic poles are magnetically oriented toward each yoke element; In the magnetic circuit assembly, the at least one permanent magnet and the yoke body form a closed magnetic circuit, but have at least two gaps formed between corresponding axial faces of different yoke elements, configured to guide the magnetic flux density arriving from the at least one permanent magnet through the yoke body, and to induce a magnetic field inward into the at least two gaps that reaches the beam passage; The at least one shunt device includes at least one permeable shunt element and is positioned at a defined location between the at least two elements of the yoke body, and the at least one shunt device allows a defined (predetermined) portion of the magnetic flux to bypass at least one portion of the magnetic circuit assembly. [Note 2] In the charged particle lens described above, particularly in Note 1, The lens has a shape that is rotationally symmetrical overall along the vertical axis; The components of the magnetic circuit assembly, namely, • At least one permanent magnet, • York body, and • At least one shunt device These are arranged concentrically (coaxially) with the vertical axis and preferably have a basic shape corresponding to a hollow cylinder or a hollow polygonal prism shape. [Note 3] In the charged particle lens described above, particularly in Note 1 or 2, The at least one shunt element comprises two or more layers stacked along the vertical axis and / or one or more sectors arranged around the vertical axis. [Note 4] In the charged particle lens described above, in particular in any of Notes 1 to 3, The at least one shunt element is composed of two or more sector elements made of a magnetic permeable material, and the two or more sector elements are each positioned at different azimuth positions around the vertical axis; At least one of the two or more sector elements comprises a permeable material having a permeability different from that of the other sector elements, thus enabling the magnetic lens to have different azimuth-varying magnetic flux densities, and therefore a azimuth-varying magnetic field around the vertical axis. [Note 5] In the charged particle lens described above, particularly in Note 4, The at least one permanent magnet is composed of at least two sub-elements, each positioned at a different azimuth around the vertical axis; At least one of the shunt device or at least one of the two or more sector elements is positioned between each of the at least two permanent magnet sub-elements. [Note 6] In the charged particle lens described above, in particular in any of Notes 1 to 5, The second yoke element constitutes the housing body of the lens assembly; the housing body encloses the other elements of the lens assembly, including all other yoke elements. [Note 7] In the charged particle lens described above, in particular in any of Notes 1 to 6, The at least one permanent magnet has a magnetization that is substantially oriented in the radial direction; The at least one shunt device includes a material with high permeability at least in a direction parallel to the substantially radially oriented (preferred) magnetization. [Note 8] In the charged particle lens described above, in particular in any of Notes 1 to 7, The aforementioned at least one permanent magnet is composed of at least two sub-elements, i.e., • Segmented according to two or more layers stacked along the vertical axis; and / or • Divided into two or more sectors arranged around the vertical axis. [Note 9] In the charged particle lens described above, particularly in Note 8, At least one shunt device is positioned between each of the two sub-elements. [Note 10] The charged particle lens described above, in particular in any of Notes 1 to 9, A sleeve insert member inserted into the beam passage (passage space) along the vertical axis and Electromagnetic lenses, including those mentioned above. The sleeve insert member surrounds the beam passage having a radius smaller than the radius of the beam passage of the charged particle lens and extends along the longitudinal axis; The sleeve insert member includes a mount body having at least a partially conductive portion and at least one conductive electrode element; The at least one electrode element is configured such that an electrical potential (referenced to) the electrical potential of a conductive portion is applied via a power source to generate an electrostatic field in the beam passage. [Note 11] In the electromagnetic lens described above, particularly in Note 10, The vertical axis of the sleeve insert member coincides with (overlaps with) the vertical axis of the charged particle lens. [Note 12] In the electromagnetic lens described above, particularly in Note 10 or 11, The (at least one) electrode element is configured to form a (charged) particle optical lens in at least one of the at least two gaps together with the magnetic field in the beam path; The focal length of the charged particle optical lens can be adjusted by modifying (changing) the electrical potential applied to the electrode element. [Note 13] In the electromagnetic lenses described above, particularly in any of Notes 10 to 12, The inner yoke shell extends along the longitudinal axis and surrounds the sleeve insert member in the circumferential direction; The at least two gaps of the magnetic circuit are (each) located at either axial end of the inner yoke shell, and each gap generates a defined (predetermined) magnetic field that extends inward into the space of the beam passage, and the electrostatic field generated by at least one of the plurality of (at least one) electrode elements of the sleeve insert member is configured to at least partially overlap the magnetic field. [Note 14] In the electromagnetic lenses described above, particularly in any of Notes 10 to 13, At least one of the multiple (at least one) electrode elements includes an electrostatic multipole electrode; The electrostatic multipole electrode includes a plurality of auxiliary electrodes uniformly arranged (at regular intervals) around the longitudinal axis along the circumferential direction, and the plurality of auxiliary electrodes can be connected to a multi-channel power supply unit that supplies potential to each auxiliary electrode individually. [Note 15] In the electromagnetic lenses described above, particularly in any of Notes 10 to 14, The plurality of electrode elements (at least one of them) include a beam aperture element that forms a limiting aperture having a predetermined radius defined around the longitudinal axis; The limiting aperture is configured to limit the width of the charged particle beam propagating along the vertical axis; The beam aperture element is connected to a current measuring device configured to measure the amount of charged particle beam absorbed by the beam aperture element. [Note 16] A charged particle optical device including a charged particle lens as described in any of Notes 1 to 9 or an electromagnetic lens as described in any of Notes 10 to 15. The apparatus is configured to influence the charged particle beam of the apparatus propagating through the lens along the vertical axis of the lens; The aforementioned lens is part of the particle optics system of the apparatus. [Note 17] In the charged particle optical apparatus described above, particularly in Note 16, The apparatus is configured as a multi-column system including multiple particle optical columns; Each column is configured to use its respective particle beam and includes its respective particle optics system, which comprises its respective configuration (instance) of a charged particle lens or an electromagnetic lens.

[0090] Within the framework of the full disclosure of the present invention (including the claims and drawings), further modifications and adjustments to the embodiments are possible based on the fundamental technical concept. Furthermore, within the framework of the full disclosure of the present invention, various combinations or 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 the full disclosure, including the claims and drawings, and various modifications and alterations that a person skilled in the art could make in accordance with the technical concept of the present invention. In particular, with respect to the numerical ranges described herein, any numerical value or sub-range included within that range should be interpreted as being specifically described, even if not otherwise stated.

[0091] Furthermore, the reference numerals in the drawings included in the claims are solely for the purpose of aiding the understanding of the invention, and are not intended to limit the present invention to the embodiments and illustrated examples.

[0092] Furthermore, the full contents of each of the above-mentioned documents are incorporated into this book through reference and are included herein. [Explanation of Symbols]

[0093] 1. Charged particle optical system 10 Charged particle lens 11 Beam passage 20 Magnetic Circuit Assembly 21 Permanent Magnets 25 York Body 30 Shunt device 31 Magnetic permeable shunt element 61 Magnetic field 100 Charged particle beam 210, 211 Permanent magnet materials 250 Inner Yoke Shell 251 Outer yoke shell 290, 291 gap cx vertical axis

Claims

1. A charged particle lens configured to modify a charged particle beam of a charged particle optical system (1), comprising: the lens comprises a beam passage (11) extending mainly along a longitudinal axis (cx) and allowing passage of a charged particle beam (100); The lens is at least one permanent magnet (21; 210, 211), - yoke body (25; 250, 251), and At least one shunt device (30) a magnetic circuit assembly (20) including: The yoke body (25) is composed of at least two yoke elements (250, 251), of which a first yoke element (250) constitutes an inner yoke shell (250) arranged to surround the beam passage (11), and a second yoke element constitutes an outer yoke shell (251) arranged to surround the inner yoke shell (250), and the at least two 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 around the inner yoke shell, and the at least one permanent magnet includes a permanent magnetic material (210, 211) having two magnetic poles magnetically oriented toward the respective yoke elements; In the magnetic circuit assembly (20), the at least one permanent magnet and the yoke body form a closed magnetic circuit, but have at least two gaps (290, 291) formed between corresponding axial faces of different yoke elements, configured to guide the magnetic flux density coming from the at least one permanent magnet through the yoke body, and to induce a magnetic field (61) inwardly reaching into the beam passage in the at least two gaps; The at least one shunt device (30) includes at least one magnetically permeable shunt element (31) and is disposed at a defined position between the at least two elements of the yoke body, the at least one shunt device (30) allowing a defined portion of the magnetic flux to bypass at least a portion of the magnetic circuit assembly. A charged particle lens, characterized by:

2. 2. The charged particle lens of claim 1, the lens has a generally rotationally symmetric shape along the longitudinal axis (cx); Components of the magnetic circuit assembly (20), namely: at least one permanent magnet (21), - yoke body (25), and At least one shunt device (30) is arranged concentrically with the longitudinal axis and preferably has a basic shape corresponding to a hollow cylinder or a hollow polygonal prism shape. A charged particle lens, characterized by:

3. 2. The charged particle lens of claim 1, The at least one shunt element (31) is composed of two or more layers (330) stacked along the longitudinal axis (c2) and / or one or more sectors (340) arranged around the longitudinal axis (c2). A charged particle lens, characterized by:

4. 2. The charged particle lens of claim 1, the at least one shunt element (31) is comprised of two or more sector elements (350, 351) made of a magnetically permeable material, the two or more sector elements being arranged at different azimuth positions around the longitudinal axis; At least one of the two or more sector elements comprises a magnetically permeable material having a magnetic permeability different from that of the magnetically permeable material of the other sector elements, thus enabling the magnetic lens to have a different azimuthal varying magnetic flux density and therefore an azimuthal varying magnetic field about the longitudinal axis (c2). A charged particle lens, characterized by:

5. 5. The charged particle lens according to claim 4, the at least one permanent magnet (21) is composed of at least two sub-elements arranged at different azimuth positions around the longitudinal axis; At least one of the shunt device (30) or at least one of the two or more sector elements is disposed between two of the at least two permanent magnet sub-elements. A charged particle lens, characterized by:

6. 2. The charged particle lens of claim 1, The second yoke element (251) constitutes a housing body (12) of the lens assembly, and the housing body (12) surrounds the other elements of the lens assembly, including all other yoke elements. A charged particle lens, characterized by:

7. 2. The charged particle lens of claim 1, said at least one permanent magnet (21) having a magnetization oriented substantially radially; The at least one shunt device (30) includes a material with high magnetic permeability at least along a direction parallel to the substantially radially oriented magnetization. A charged particle lens, characterized by:

8. 2. The charged particle lens of claim 1, The at least one permanent magnet (21) is composed of at least two sub-elements, namely: - segmented according to two or more layers (220) stacked along a longitudinal axis (c1); and / or - divided into two or more sectors (240) arranged around a longitudinal axis (c1); A charged particle lens, characterized by:

9. 9. The charged particle lens of claim 8, At least one shunt device (30) is disposed between each two of said at least two sub-elements. A charged particle lens, characterized by:

10. A charged particle lens according to any one of claims 1 to 9; a sleeve insert member (50) inserted into the beam passage (11) along the longitudinal axis (cx); An electromagnetic lens comprising: the sleeve insert member (50) encloses a beam path (55) having a radius (r3) smaller than the radius (r2) of the beam path (11) of the charged particle lens and extends along a longitudinal axis (c3); the sleeve insert member (50) includes a mount 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 electrode element is configured such that an electric potential relative to the electric potential of the conductive portion (51 a) is applied to the at least one electrode element via a power source (70) to generate an electrostatic field (65) in the beam path. An electromagnetic lens characterized by:

11. 11. The electromagnetic lens of claim 10, The longitudinal axis (c3) of the sleeve insert member (50) coincides with the longitudinal axis (cx) of the charged particle lens. An electromagnetic lens characterized by:

12. 11. The electromagnetic lens of claim 10, the electrode elements are configured to form a particle-optical lens together with a magnetic field (61) in the beam path (55) in at least one of the at least two gaps (290, 291); The focal length of the charged particle optical lens is adjustable by modifying the electrical potential applied to the electrode elements. An electromagnetic lens characterized by:

13. 11. The electromagnetic lens of claim 10, the inner yoke shell (250) extends along the longitudinal axis (c3) and circumferentially surrounds the sleeve insert member (50); The at least two gaps (290, 291) of the magnetic circuit are arranged at either axial end of the inner yoke shell, and each gap generates a defined magnetic field (61) that extends inward and reaches into the space of the beam passage (11, 55), and the electrostatic field (65) generated by at least one of the plurality of electrode elements (52a, 53a, 52b, 53b) of the sleeve insert member is configured to at least partially overlap with the magnetic field. An electromagnetic lens characterized by:

14. 11. The electromagnetic lens of claim 10, At least one of the plurality of electrode elements includes an electrostatic multipole electrode (53), which includes a plurality of sub-electrodes (530) uniformly arranged around the longitudinal axis (c3) along a circumferential direction, the sub-electrodes being connectable to a multi-channel power supply unit (723) that individually supplies a potential to each of the sub-electrodes. An electromagnetic lens characterized by:

15. 11. The electromagnetic lens of claim 10, the plurality of electrode elements include a beam aperture element (54) forming a limiting aperture (540) having a defined radius (r4) about said longitudinal axis (c3); the limiting aperture is configured to limit the lateral width of a charged particle beam (100) propagating along the longitudinal axis; and 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:

16. A charged particle optical device including the charged particle lens according to any one of claims 1 to 9, the device is configured to influence a beam of charged particles (50; e, f) of the device propagating through the lens along a longitudinal axis (cx) of the lens, the lens is part of the particle-optical system (3, 5) of the device; A charged particle optical device comprising:

17. 17. A charged particle optical device according to claim 16, the apparatus 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:

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