Adjustable permanent magnetic lens having thermal control device

Abstract

To provide a charged particle lens that has a permanent magnet and furthermore enables the optical property of the lens to be highly accurately adjusted.SOLUTION: A fine-adjustable charged particle lens (10) comprises a magnetic circuit assembly (20) including: a permanent magnet (21); and a yoke body (25) surrounding a passage space (11) extended along a longitudinal axis (cx). The permanent magnet is arranged between an inner yoke component (250) and an outer yoke component (251) so as to form a magnetic circuit having at least two gaps (290 and 291), and generating a magnetic field (61) reaching inwards into a passage space. Into the passage space, a sleeve insert member (50) having an electrostatic electrode capable of forming a magnetic field which can be spatially overlapped with the magnetic field can be inserted. In order to modify the magnetic field in accordance with a magnetic flux in each gap, a thermal control element (31) distributed in the yoke body introduces heat into a construction element of the magnetic circuit assembly, or removes the heat from the construction element, and therefore, thermally controls or adjusts a magnetic behavior of the construction element.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This application claims the benefit of Paris Convention priority from European Patent Application No. 22185177.7, filed July 15, 2022, the entire contents of which are incorporated herein by reference.

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

[0003] The invention further relates to electromagnetic lenses, including charged particle lenses, as well as charged particle optical devices including lenses of said type. [Background technology]

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

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

[0006] Such a multi-column device (an example is discussed below with reference to FIG. 14) allows significantly higher currents through the charged particle beam while overcoming the limitations of the trade-off between current and optical aberrations found in single-column systems. This is due to the fact that the total current delivered to the target is split into multiple optical axes, while the resolution limit is dictated by the amount of current per optical axis. Single columns of this type are known in the prior art, such as in the applicant's US 6,768,125, EP 2 187 427 A1 (= US 8,222,621) and EP 2 363 875 A1 (= US 8,378,320). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US6,768,125 [Patent Document 2] EP2 187 427 A1 [Patent Document 3] US8,222,621 [Patent Document 4] EP2 363 875 A1 [Patent Document 5] US8,378,320 Summary of the Invention [Problem to be solved by the invention]

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

[0009] To use such a system as a high-throughput direct wafer write machine, it would be necessary to place a significant 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 that is only a fraction of the overall wafer width; for example, for a typical 300 mm (12" (inch)) wafer, a diameter of approximately 30 mm may be used. On the other hand, slim diameter magnetic lenses cannot be realized with coil-type magnetic lenses, because a reduction in the column diameter would correspond to extremely large Joule heating due to the large currents required to drive the coils to generate a sufficiently strong magnetic field; however, there is insufficient space for a suitable temperature control system, including high-precision sensors and isotropic uniform cooling, that would be required for a conventional coil-type magnetic lens.

[0010] The above limitations imposed by thermal-related and geometrical (spatial) requirements are severe, but can be overcome by employing magnetic lenses based on permanent magnets together with a magnetically permeable yoke body for directing the magnetic flux and thus generating the magnetic field, as in a possible embodiment of the present invention. However, such permanent magnets cannot be tuned very well after the manufacturing and assembly is completed, and therefore their use in magnetic lenses is limited. This represents a serious drawback to coil-based magnetic lenses whose magnetic field is controllable by adjusting the current flowing through the coil. The accuracy of magnet manufacturers is crucial for the operational purpose of magnetic lenses including such magnets, especially considering the inherent limitations on the accuracy of the targeted magnetic field based on the manufacturing and assembly; current accuracy limitations correspond to deviations of approximately 1% to 5% from the target magnetic field; the magnetic field strength is on the order of 1 T.

[0011] The deviations mentioned above are due to manufacturing tolerances and statistical uncertainties, which are practically unavoidable for a manufacturing process with reasonable yields of magnetic lenses for mass production. The present invention provides a new approach to compensate for these deviations by including an additional component that allows tuning of the magnetic field during the assembly of the lens. The present invention removes the (unrealistic) precision burden 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, since Applicant's invention can compensate for deviations of the actual permanent magnets from the desired nominal (rated) magnetic field strength, and even tolerate larger deviations as long as the geometric parameters of the system are still within specifications.

[0012] Tuning of permanent magnet-based charged particle lenses in-situ, i.e. during operation of the device, is typically performed by combining them with one or more additional electric lenses; i.e. 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. However, this has at least the above-mentioned heating and geometrical (spatial) problems that make it not suitable for at least some of the embodiments of the present invention, although it is possible to tune the magnetic field. Furthermore, the magnetic field of the above-mentioned prior art magnetic lenses is poorly confined to the space of the charged particle lens itself, which causes serious cross-effects when multiple lenses are juxtaposed in a multi-column system.

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

[0014] According to a first aspect of the invention, there is provided a charged particle lens configured to modify a charged particle beam of a charged particle optical system. the lens extends primarily along a longitudinal axis and includes a passage space for permitting passage of the charged particle beam; The lens is at least one permanent magnet, and -Yoke body a magnetic circuit assembly including: the yoke body is composed of at least two yoke elements, of which a first yoke element constitutes an inner yoke shell arranged to surround the passage space, and a second yoke element constitutes an outer yoke shell arranged to surround the inner yoke shell, the at least two yoke elements are arranged around the longitudinal axis, and include a highly permeable material; the at least one permanent magnet is disposed between the at least two yoke elements and around the inner yoke shell, the at least one permanent magnet including a permanent magnet material having two magnetic poles magnetically oriented toward the respective yoke elements; In the magnetic circuit assembly, the at least one permanent magnet and the yoke body 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 coming from the at least one permanent magnet through the yoke body, and to induce a magnetic field in the at least two gaps that reaches the passage space inwardly; and the charged particle lens comprises a temperature control assembly including at least one temperature control element disposed in the yoke body; the temperature control assembly is configured to control and / or actively vary a temperature of at least a portion of at least one component of the magnetic circuit assembly using the at least one temperature control element to introduce heat to and / or remove heat from the component to control and / or modify magnetic flux in the magnetic circuit. (Form 1) According to a second aspect of the present invention, there is provided a charged particle lens according to the present invention, and a sleeve insert member inserted into said passage space along said longitudinal axis. An electromagnetic lens is provided, comprising: the sleeve insert member encircles a beam path having a radius smaller than a radius of a path space of the charged particle lens and extends along a longitudinal axis; the sleeve insert member including a mount body having at least one conductive portion and at least one conductive electrode element; the at least one electrode element is configured to have an electric potential applied to it via a power source relative to an electric potential of the at least one conductive portion to generate an electrostatic field in the beam path; said (at least one) electrode element is configured to form, in at least one of said (at least two) gaps, a particle-optical lens together with a magnetic field in said beam path; The focal length of the charged particle optical lens is adjustable by modifying the electrical potential applied to said electrode elements. It is characterized by the above (Form 16). According to a third aspect of the present invention there is provided a charged particle optical apparatus including a charged particle lens according to the present invention. the charged particle optical device is configured to affect a charged particle beam of the charged particle optical device propagating through the charged particle lens along a longitudinal axis of the charged particle lens; the charged particle lens being part of a particle-optical system of the charged particle optical device; It is characterized by the above (Form 21). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (Mode 1) See the first aspect of the present invention above. (Feature 2) In the charged particle lens according to feature 1, It is preferable that the at least one temperature control element includes at least one of a heating device capable of generating heat within the magnetic circuit assembly and a cooling device operated by a medium capable of removing and transporting heat from the magnetic circuit assembly. (Feature 3) In the charged particle lens according to feature 1, the charged particle lens having a generally rotationally symmetric shape along the longitudinal axis; Components of the magnetic circuit assembly, namely: at least one permanent magnet, -Yoke body, and At least one temperature control element is preferably arranged concentrically about said longitudinal axis. (Feature 4) In the charged particle lens according to feature 3, The components of the magnetic circuit assembly preferably have a basic shape corresponding to a hollow cylinder or a hollow polygonal prism shape. (Feature 5) In the charged particle lens according to feature 1, The at least one temperature control element preferably comprises a thermal interface to the exterior of the charged particle lens, configured to transport heat in and / or out. (Feature 6) In the charged particle lens according to feature 5, The thermal interface is preferably configured to transfer heat in and / or out via suitable holes formed in the outer yoke shell. (Feature 7) In the charged particle lens according to feature 1, The temperature control assembly preferably includes two or more temperature control elements positioned at different locations associated with different components of the magnetic circuit assembly and configured to create a temperature gradient along the longitudinal axis in the magnetic circuit assembly. (Feature 8) The charged particle lens according to feature 1, Preferably, the at least one temperature control element is configured to operate at least in part like a magnetic multipole, including two or more sub-elements configured to create an azimuthal temperature gradient to enable the magnetic lens to have different azimuthalically varying magnetic flux densities and therefore azimuthally varying magnetic fields about said longitudinal axis. (Feature 9) The charged particle lens according to feature 8, The sub-elements are preferably formed as sectors of an annularly shaped temperature control element. (Feature 10) The charged particle lens according to feature 8, The sub-elements preferably comprise separate thermal interfaces to the exterior of the charged particle lens, configured to transport heat in and / or out. (Feature 11) The charged particle lens according to feature 10, The thermal interfaces of the sub-elements are preferably configured to transfer heat in and / or out via suitable holes formed in the outer yoke shell. (Feature 12) In the charged particle lens according to feature 1, Preferably, the second yoke element forms a housing body for the lens assembly, which housing body encloses the other elements of the lens assembly including all other yoke elements. (Feature 13) The charged particle lens according to feature 1, Preferably, the at least one permanent magnet has a substantially radially oriented magnetization. (Feature 14) In the charged particle lens according to feature 1, The at least one permanent magnet is composed of at least two sub-elements, namely: · segmented according to two or more layers stacked along a longitudinal axis; and / or Preferably divided into two or more sectors arranged around the longitudinal axis. (Feature 15) The charged particle lens according to feature 14, Preferably, at least one temperature control element is disposed between each two of said at least two sub-elements. (Mode 16) See the second aspect of the present invention above. (Feature 17) The electromagnetic lens according to feature 16, the inner yoke shell extends along the longitudinal axis and circumferentially surrounds the sleeve insert member; It is preferable that the at least two gaps in the magnetic circuit are (respectively) arranged at either axial end of the inner yoke shell, each gap generates a defined magnetic field which extends inwardly into the space of the beam passage, and the electrostatic field generated by at least one of the multiple electrode elements of the sleeve insert member is configured to at least partially overlap with the magnetic field. (Feature 18) The electromagnetic lens according to feature 16, It is preferred that at least one of the plurality of electrode elements includes an electrostatic multipole electrode, the electrostatic multipole electrode including a plurality of sub-electrodes spaced (uniformly) circumferentially around the longitudinal axis, the plurality of sub-electrodes being connectable to a multi-channel power supply unit which individually supplies a potential to each sub-electrode. (Feature 19) The electromagnetic lens according to feature 16, the plurality of electrode elements including a beam aperture element forming a limiting aperture having a defined (predetermined) radius about said longitudinal axis; the limiting aperture is configured to limit a lateral width of a charged particle beam propagating along the longitudinal axis; and The beam aperture element is preferably connected to a current measuring device arranged to measure the amount of the charged particle beam absorbed in the beam aperture element. (Feature 20) The electromagnetic lens according to feature 16, The longitudinal axis of the sleeve insert member is preferably coincident with the longitudinal axis of the charged particle lens. (Mode 21) See the third aspect of the present invention above. (Feature 22) In the charged particle optical apparatus according to feature 21, the charged particle optical device is configured as a multi-column system including a plurality of particle optical columns; Each column is configured to use a respective particle beam and preferably includes a respective particle-optical system including a respective instance of a charged particle lens or an electromagnetic lens.

[0016] The above object is achieved by a lens configured to modify (e.g., shape, focus / defocus, or otherwise manipulate) a charged particle beam of a charged particle optical device. The lens extends primarily along a longitudinal axis and includes a passage space or beam passage allowing passage of the charged particle beam, the lens further includes a magnetic circuit assembly including at least one permanent magnet and a yoke body composed of at least two elements of high magnetic permeability, and further includes a temperature control assembly including at least one temperature control element positioned in the yoke body. The yoke body includes a first yoke element arranged to surround the passage space and capable of forming an inner yoke shell, and a second yoke element arranged to surround the inner yoke shell and capable of forming an outer yoke shell (here, the terms "inner" and "outer" refer to their respective relative positions within the lens assembly and on the central axis); these yoke elements are arranged around the longitudinal axis and are suitably made of a ferromagnetic body or a highly magnetically permeable material such as a ferromagnetic material.

[0017] At least one permanent magnet is disposed between the at least two yoke elements, i.e., around the inner yoke shell and inside the outer yoke shell, and includes a permanent magnet material whose two magnetic poles are magnetically oriented primarily toward the respective yoke elements.

[0018] The permanent magnets and the yoke body form a closed magnetic circuit, except for having at least two gaps formed between corresponding faces of the different yoke elements and arranged in the beam path (e.g., positioned at each of the axial ends between the (axial end) face of the inner yoke shell and the face of the outer yoke shell corresponding thereto); thus, the magnetic circuit induces a magnetic field in the gaps that guides the magnetic flux generated by the permanent magnets through the yoke body and also reaches into the beam path. It is this magnetic field from the gaps that is used to form a magnetic lens for the charged particle beam propagating in the beam path along the longitudinal axis. The formation of the magnetic lens typically achieves a magnetic field accuracy within a range of 1% to 5% above and below a target value. The temperature control assembly is configured to control and actively vary the temperature of at least a portion of at least one component of the magnetic circuit assembly for controlling and / or modifying the magnetic flux of the magnetic circuit during operation by means of its at least one temperature control element, and by means of at least one temperature control element for introducing heat to and / or removing heat from the element. The at least one temperature control element may include, for example, a heating device capable of generating heat, for example from electrical energy supplied to the heating device, in the magnetic circuit assembly, and / or a cooling device operating with a medium (such as a coolant) to remove and transport heat from the magnetic circuit assembly. The modified magnetic flux then modulates the magnetic field in the gaps, which is used to form magnetic lenses inside the beam passage acting on the particle beam passing through the beam passage. Thus, the invention allows an improved control of the particle lens properties with better precision. The precision of such (temperature controlled) lenses may be within 0.1%-0.5% of the desired value of the magnetic field, thus resulting in the formation of magnetic lenses with an efficiency of almost an order of magnitude greater, i.e. closer to the design optical properties, e.g. focal length, compared to the performance of the same magnetic lens without such a device (temperature control assembly). The invention also allows the properties of the magnetic circuit during operation to be controlled, such as adjusted or stabilized, depending on the actual situation.

[0019] In the technical solution underlying the present invention, the yoke elements and at least one permanent magnet together form a closed magnetic circuit with at least two gaps, but optionally with three or more gaps, positioned next to the beam path; since these gaps serve to induce a defined magnetic flux density and thus a magnetic field that reaches into the beam path, acting as a magnetic lens. The temperature control elements of the present invention can also be used to compensate for deviations of the magnetic field from a nominal value. The temperature control element of the present invention is positioned in a position suitable for influencing the temperature state of the magnetic circuit element, but does not directly influence the selected magnetic flux. It can also be used for introducing asymmetries and tuning of the magnetic circuit assembly, for example by shifting the device along the longitudinal axis. Therefore, deviations in strength and partly also in direction from the desired nominal value can be reduced; thus, it is possible to achieve certain properties according to the initial design that would otherwise not be compatible with the permanent magnet manufacturing process and its immanent tolerances.

[0020] The invention allows for improved control of the temperature state of the magnetic circuit. This can be used to maintain the magnetic field at a desired value (operation point) and thus stabilize the operation of the magnetic circuit and therefore of the magnetic / electromagnetic lens. Furthermore, the invention allows for active modification of the magnetic circuit and the lens, which can be used to cause tuning of the magnetic and electromagnetic lenses. Another advantage is that temperature regulation can be used to compensate for variations in the magnet elements, thus facilitating the use of permanent magnets currently manufactured and that can be incorporated into charged particle lenses, by adjusting the magnetic flux with the temperature control elements of the invention. Thus, the magnetic field that defines the lens effect at the position of the gap can be fine-tuned. The invention therefore allows for compensation of limited precision in the manufacture of permanent magnet materials and elements, clearly helping to limit their effects. The invention also leads to a reduction of stray magnetic fields.

[0021] Furthermore, within the framework of the invention several optional developments are conceivable, which can be combined if appropriate, such as:

[0022] For example, one yoke element may embody (constitute) a housing body of a lens that surrounds other parts (parts) of the magnetic circuit, in particular the other yoke elements, as well as the (at least one) permanent magnet and (at least one) temperature control element. In general, several parts (parts) of the magnetic circuit may be used to constitute a housing of the lens and at least one permanent magnet and / or at least one temperature control element, all of which are arranged around the inner yoke shell, and / or all the yoke elements may also be part of the housing body of the lens.

[0023] Suitable holders may be provided inside the yoke body for supporting one or more temperature control elements at their respective defined positions. In particular, a holder element may be provided configured to maintain a temperature control element in a defined position between at least two elements of the yoke body, which may be configured to precisely define thermal contact with corresponding elements of the magnetic circuit assembly.

[0024] Advantageously, the temperature control element may comprise a thermal interface to the exterior of the charged particle lens configured to transport heat to the interior and / or exterior, preferably via suitable holes(s) formed in the outer yoke shell.

[0025] Additionally, the temperature control assembly may include two or more temperature control elements positioned at different locations associated with different elements of the magnetic circuit or magnetic circuit assembly, which may be used to generate a temperature gradient along the longitudinal axis in the magnetic circuit assembly.

[0026] Furthermore, the temperature control element and / or its components may be of composite structure, e.g. composed of one or more sectors arranged around the longitudinal axis and / or segmented into two or more layers stacked along the longitudinal axis. The sub-elements (sectors, segments and / or layers) may also be formed of varying materials with different temperature properties (heat capacity, thermal conductivity) to form local gradients of magnetic flux reduction. Thus, the temperature control element of the present invention may include two or more sub-elements, preferably formed as sectors of an annularly shaped temperature control element. This may be configured to generate an azimuthal temperature gradient to enable the magnetic lens to have different azimuthal varying magnetic flux densities and thus azimuthal varying magnetic fields around the longitudinal axis. Thus, the composite temperature control element may at least partially operate like a magnetic multipole. These temperature (control) sub-elements may further comprise separate thermal interfaces to the exterior of the charged particle lens configured to transport heat to the interior and / or exterior, for example via suitable holes(s) formed in the outer yoke shell.

[0027] In many typical configurations, the (at least one) permanent magnet may have a magnetization that is substantially radially oriented, where the term "substantially radial" is used to include cases where the orientation is "operationally radial" such that magnetic flux through the permanent magnet or temperature control element to the yoke element generally flows along a radial direction (from a relatively inner yoke element to a relatively outer yoke element or vice versa).

[0028] In an advantageous development, the (at least one) permanent magnet may also be composed of two or more layers stacked along the longitudinal axis; furthermore, it may also be suitable to embody (compose) the (at least one) permanent magnet composed of three or more sectors arranged circumferentially around the longitudinal axis, in which case the magnet sectors are preferably substantially wedge-shaped elements forming sectors about the longitudinal axis.

[0029] A further aspect of the invention relates to an electromagnetic lens comprising a charged particle lens according to the invention and a sleeve insert member inserted into the beam passage along a longitudinal axis, the sleeve insert member surrounding a smaller portion of the beam passage opening but extending between its ends along the longitudinal axis; preferably overlapping at least the gap of the yoke element. The sleeve insert member comprises one or more conductive electrode elements to which respective electric potentials can be applied by means of a power supply to generate electric fields in the beam passage. Advantageously, the electrode elements can be configured to form a particle-optical lens in combination with a magnetic field in the (at least one) gap in the passage opening. It should be noted that optical parameters of the particle-optical lens, such as the focal length, can be further adjusted by modifying (changing) the electric potentials applied to the electrode elements.

[0030] According to one preferred geometrical layout, the yoke body may extend between the two axial ends of the beam passage, thus forming it; in particular, a first element, for example an inner yoke shell, may extend through the central part of the passage, but at both ends maintain the gap open towards a second element, for example an outer yoke shell, which radially and axially surrounds the inner yoke shell, preferably extending on both sides; thus, the yoke elements may form a geometry of two hollow cylinders nested concentrically. The inner yoke shell thus surrounds at least a portion of the sleeve insert member; the gaps of the magnetic circuit each induce a magnetic field that reaches inwardly into the passage opening and overlaps with the electric field generated by the electrode elements of the sleeve insert member, thus forming an electromagnetic lens. Such ultra-fine electromagnetic lenses may be accurate to a precision 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, ie during the time that the charged particle beam is passing through, by modifying the electrical potential applied to the electrode elements.

[0031] In many configurations, the sleeve insert member may also include a ceramic body in which the electrode elements are embodied as a conductive coating, each having a defined shape and extent.

[0032] Furthermore, in many embodiments of the invention, at least one of the electrode elements may comprise an electrostatic multipole electrode that includes a number of sub-electrodes uniformly spaced circumferentially around a longitudinal axis, such that the lens can deflect or shape a charged particle beam that traverses the electrode element, but the electrical potentials applied to the sub-electrodes of the element may be defined to form a multipole electric field.

[0033] In many forms of the lens of the invention, particularly when the lens is intended to be used in association with a pattern definition system (PD), a beam aperture element may be provided between the electrode elements forming a limiting aperture with a defined radius around the longitudinal axis, which limits the lateral 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 particles intentionally deflected in the pattern definition system; it is intended to prevent the particles from reaching the target of the charged particle beam. Furthermore, for example, the beam aperture element may be connected to a current measuring device, which may be used to measure the amount of charged particles absorbed in the beam aperture element. In front of such a beam aperture element, i.e. upstream, it is advantageous to have an electrostatic multipole electrode configured to determine the transverse position of the beam with respect to the longitudinal axis by applying a number of different suitable electrostatic potentials to the secondary electrodes, thus scanning the beam across the aperture.

[0034] Preferably, the charged particle lens may have a shape that is generally rotationally symmetrical about said longitudinal axis, in which case the elements of the magnetic circuit assembly are arranged coaxially with said longitudinal axis and preferably have a basic shape corresponding to a hollow cylinder or a hollow polygonal prism shape.

[0035] Unlike known magnetic lenses such as those shown in US 9,165,745, the electromagnetic lens of the present invention has a completely closed magnetic loop, with only a number of "air gaps" in the housing body, which allow the magnetic field to be placed in the desired areas of the optical axis, thus reducing the influence of stray magnetic fields (present in single gap systems following Ampere's circuit law) that adversely affect the performance of electromagnetic lenses such as those employed in charged particle multi-beam nanopatterning devices. Therefore, in order to minimize the stray magnetic fields present in the above-mentioned prior art systems, it is highly advantageous to provide (at least) two gaps. However, it will be clear that the number of gaps may be greater, such as three or four or more, depending on the particular application of the lens.

[0036] For at least the above reasons, the present invention and its application in writer tools such as multi-column, multi-beam charged particle patterning systems (e.g., for direct writing of substrates) provides a unique combination of magnetic, electrical, and calibration elements that is expected to have a significant impact on the deployment of high throughput industrial processes for integrated circuits. The present invention significantly facilitates the layout, construction, fine tuning, and even ultra-fine tuning of writer tools, particularly for the control of multi-column, multi-beam mask writers.

[0037] A further aspect of the invention is directed to a charged particle optical device including a charged particle lens according to the invention (including an electromagnetic lens according to the invention) configured to affect a charged particle beam of the device propagating through the lens along its optical axis, the lens being part of a particle-optical system of the device suitable for a magnetic lens. In particular, the device may be preferably embodied as a multi-column system including a plurality of charged particle optical columns, each column using a respective particle beam and including a respective optical system including a respective lens of the invention.

[0038] In the following, illustrative and non-limiting embodiments or examples, as illustrated in the drawings, will be discussed to further explain the present invention. [Brief description of the drawings]

[0039] [Figure 1] An example of a charged particle lens according to a first aspect of the invention, where (A) (on the left side of the page) is a longitudinal section of a charged particle lens including a temperature control assembly according to the invention, and (B) is an example plot of the magnitude of the axial component of the magnetic field measured at the position of the central axis as a function of the ordinate of (A) without (dashed line) and with (solid line) a temperature control element. [Diagram 2] FIG. 1(A) shows an example of one form of symmetrical ring-shaped temperature control element configured to control the magnetic lens of FIG. 1(A); (A) is a cutaway view of the element and (B) shows a cross-section thereof, including an optional temperature sensor. [Diagram 3] 1 shows an example of one form of temperature control element constructed from multiple stacked layers. [Figure 4] 1 shows an example of one form of temperature control element made up of multiple sectors. [Diagram 5] An example of one form of temperature control element constructed from multiple sectors having materials with varying (different) temperature properties (e.g., thermal conductivity, heat capacity) allowing the temperature control element to have asymmetric properties about a central axis. [Figure 6] An example of a charged particle lens according to another aspect of the invention, the lens having temperature control elements arranged asymmetrically with respect to the ordinate of the lens. (A) (on the left side of the page) is a longitudinal cross-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 at the central axis position as a function of the ordinate of (A) without temperature control (dashed line) and with asymmetric temperature control (dotted line). [Figure 7] 1A and 1B are a perspective view and a longitudinal cross-sectional view, respectively, of an example of a permanent magnet constructed from multiple ring elements having radial magnetization. [Figure 8]1 shows cross-sectional views of several examples of permanent magnet configurations, some of which ((B) through (D)) are sectorized (divided into multiple sectors) with the preferred magnetization variation. [Figure 9] An example of a charged particle lens according to a further aspect of the invention including a sleeve insert: (A) (on the left side of the page) is a longitudinal cross-section of the charged particle lens and the electrical sleeve insert therein, forming an electrostatic lens system; (B) is a plot of the magnitude of the axial components of the magnetic field (solid line) and electric field (dashed line) of the temperature regulated magnetic lens measured at the central axis position as a function of the ordinate of (A). [Figure 10] 9(B) is a schematic overview of an example of a voltage supply and its components connected to a sleeve insert member in one embodiment of the lens of FIG. 9(A). [Figure 11] FIG. 2 is a cross-sectional view of an example of a multipole electrode having eight sub-electrodes. [Figure 12] FIG. 2 is an enlarged detailed view of a calibration aperture and a preceding multipole as elements of a sleeve insert member of an example electromagnetic lens according to one aspect of the present invention. [Figure 13] FIG. 2 is a cross-sectional view of an example slim column writer tool incorporating an example charged particle lens of the present invention. [Figure 14] 1 shows an example of a multi-column writer tool incorporating multiple instances of the lenses of the present invention, (A) a longitudinal cross-sectional view of the multi-column writer tool, (B) a detailed view of a portion including the lenses and one embodiment of a multi-lens holder apparatus. [Figure 15] A typical example of the fundamental dependence of magnetization on temperature for a permanent magnet ((A)) and a magnetic yoke ((B)). EXAMPLES

[0040] The detailed discussion of exemplary embodiments of the present invention given below discloses the basic idea, realization and further advantageous developments of the present invention. It should be clear to one skilled in the art to combine any of some or all of the embodiments discussed herein as deemed suitable for a particular application of the present invention. Throughout this disclosure, terms such as "advantageous", "exemplary", "typical", "preferably" or "preferable" refer to elements or dimensions that are particularly suitable - but not essential - for the present invention or an embodiment thereof, and can be modified, unless expressly required, if deemed suitable by the skilled artisan. It is understood that the present invention is not limited to the exemplary embodiments discussed below, which are given for the purpose of illustrating the present invention and merely present preferred embodiments of the present invention. Within the scope of this disclosure, terms relating to the vertical direction, such as "up" or "down", should be understood with respect to the direction of a particle beam traversing an electromagnetic lens, which is considered to travel downward ("vertically") along a central (or vertical) axis. This vertical axis is generally identified (identified) by the Z direction, which intersects with the X and Y directions.

[0041] Charged Particle Lens

[0042] FIG. 1(A) shows an example of a charged particle lens 10 according to a first aspect of the invention in longitudinal section, i.e. along a section through its central axis cx. For better clarity, the components are not shown to scale. The lens may be used to embody the lens 10 of the writer tool 1 of FIG. 13 or the multi-column writer tool 40 of FIG. 14 (see below), in which case it is used as an objective lens, but it will be clear that it is suitable for use in many other particle-optical devices that may embody single-column or multi-column architectures, as for example disclosed in the applicant's US 9,443,699 and US 9,495,499, the disclosures of which are incorporated herein by reference.

[0043] The charged particle lens 10 includes a beam passage 11 for a charged particle beam 100 traversing the assembly, and a magnetic circuit assembly 20 including at least one permanent magnet 210, 211, a yoke body 25 having at least two gaps 290, 291, and a temperature control assembly 30 according to the present invention. The magnets typically have a residual magnetization of approximately 1 T and TIFF2024012118000002.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 is made of a highly permeable material; the yoke elements form at least two gaps 290, 291 at two different axial positions, in which the magnetic flux flowing through the magnetic circuit assembly will induce a magnetic field that reaches into the beam path 11. Furthermore, the temperature control assembly 30 includes at least one temperature control element 31 that can transport heat to and / or from its surroundings through thermal contacts. The magnetic permeability of the yoke body 25 and the magnetization of the magnet 21 depend on their temperatures. Using this, the strength of the magnetic field that reaches the beam path 11 can be adjusted by adjusting the temperature of the yokes and magnets.

[0044] Depending on the strength of the magnetic lens effect, the charged particle beam 100 may also form a crossover xo within the beam passage 11, i.e., the beam achieves a minimum lateral width while crossing the central axis cx; the dashed line symbolically indicates the envelope of the charged particle beam as it propagates through the lens when placed in an exemplary particle beam exposure system (such as the lithography tool 1 of FIG. 13 or the multi-column lithography tool 40 of FIG. 14).

[0045] In typical configurations, the charged particle lens 10 may have the following exemplary dimensions: an overall height h1 of approximately 50 mm to 100 mm, and an internal height h2 of approximately 10 mm to 100 mm, typically less than the overall height h1, allowing for an outermost yoke element 251 (also referred to as an outer yoke shell) to serve as a housing and shield body for the lens assembly; an outer radius r1 of approximately 10 mm to 20 mm, allowing for placement in a multi-column writer tool 40 of FIG. 14; and an aperture radius r2 of approximately 0.1 mm to 5 mm, i.e., wide enough to allow for charged particle beam passage; and may also accommodate additional insert members (see FIG. 10 below). These magnets, gaps, and temperature control elements may typically have a thickness of approximately 1 mm to 5 mm, with the yoke elements having radial thicknesses of approximately the same dimensions. The size of the elements is selected as appropriate for each application and charged particle device, but in the illustrated example the geometric dimensions are typically on the order of several millimeters.

[0046] The charged particle lens 10 is typically positioned in the particle beam exposure system so that its central axis cx coincides with the optical axis c5 of the exposure system (see FIG. 13); however, those skilled in the art will recognize that other relative positions can be selected depending on the application of the charged particle lens according to the present invention.

[0047] Magnetic Circuit and Temperature Control Assembly

[0048] According to the present invention, the magnetic circuit assembly 20 and the corresponding magnetic lens include a temperature control assembly 30 including at least one temperature control element 31 and components for powering and controlling it. As already mentioned, the temperature control element has the function of modifying the temperature of the adjacent elements (or parts thereof) of the magnetic circuit assembly, thereby adjusting or even changing the magnetic properties of the elements thus affected, which in turn changes the magnetic flux density in the yoke gaps 290, 291.

[0049] A significant advantage of adding a temperature control element to a permanent magnet lens is that it allows for in-situ adjustment of the magnetic flux in the magnetic circuit. Thus, whenever there is a change in the magnetic properties of the magnetic lens assembly (such as aging of the magnet) or a change in the thermal input / output of the magnetic lens assembly, the present invention provides for compensating for such changes with at least one temperature control element.

[0050] As shown in Figures 2(A) and 2(B), the temperature control element 31 is supported in the assembly by one or more dedicated holder devices 32. The temperature control element 31 and its associated components (such as the holder devices) preferably have an essentially symmetrical ring shape. The holder devices 32 are configured to position the element in the space between the yoke elements; they also function to precisely define the thermal contact between the temperature control element 31 and the corresponding components of the magnetic circuit assembly 20, such as the adjacent permanent magnets 210, 211. Only one holder device 32 is shown in Figure 2(A) for better visibility of the temperature control element.

[0051] To enable heating, the temperature control element 31 may include an electric circuit configured to heat its surroundings by resistive heating. This electric circuit is powered by an electric current passing through an electric line 310 and through an electrically resistive material 311 embedded in the (otherwise electrically insulating) temperature control element 31. On the other hand, to enable cooling, the temperature (control) element 31 may include one or more conduits 312 formed in its interior and allowing the passage of a cooling liquid to cool its surroundings. The cooling liquid circulates through at least a pair of inlet-outlet connections 313. Excess heat or the absence of heat in the cooling liquid causes a flow of thermal energy through the holder 32 to or from the yoke(s) and / or magnet(s). The holder has a specific thermal conductivity, appropriately selected to achieve the desired thermal behavior. The heating and / or cooling power of the temperature control element 31 and the thermal conductivity and contact surfaces of the thermally related elements define the thermal behavior of the temperature control assembly, particularly with regard to the delay in achieving the desired temperature in the yoke.

[0052] Both the heating circuit 311 and the cooling conduits 312 of the temperature control element, as well as the electrical lines 310, are supplied through an interface 33 to the outside of the magnetic lens assembly for connection to the power supply and chiller element 34 of the temperature control assembly (FIG. 1). The power supply supplies the current for the heating circuit through the electrical lines 310, while the chiller cools and pumps the cooling liquid to the conduits 312 of the temperature control element through at least a pair of inlet-outlet connections 313. Both subsystems require a sufficient amount of power for the intended temperature control. Advantageously, the interface 33 may include electrical conductors and conduits for the cooling liquid (or other suitable medium for transporting heat) in a common insulating sleeve. The interface 33 traverses the outer housing or outer yoke shell 251. To achieve this, several holes may be drilled radially inward at different angular positions. It is important to consider the effect of these holes on the magnetic behavior of the yoke, since a group of holes with a large asymmetrical feature can cause an asymmetrical effect on the generated magnetic field that is usually undesirable. For example, one suitable configuration to address this issue is to provide a set of holes, e.g., 16 holes, spaced at regular intervals around the circumference, with the size of these holes being as small as possible while still providing the necessary cross-section for the coolant conduits and electrical lines.

[0053] In one advantageous form of the invention, at least one temperature sensor 35 may be provided inside the magnetic lens assembly (see FIG. 2B) to monitor the temperature of the lens elements. This serves to monitor the thermal conditions and effects on the magnetic behavior, allowing the realization of a control loop, if desired. The at least one sensor 35 may be connected to an external part of the temperature control assembly 30 via a temperature control interface 33 by a sensor line 36. This may be used to stabilize the thermal and magnetic properties of the magnetic circuit in a desired state of operation, for example by controlling the temperature at the location of one or more sensors to a desired set point.

[0054] The present invention utilizes the physical concepts behind the temperature-dependent magnetic properties of a ferromagnetic material, typically iron, whose temperature is equal to or exceeds its Curie temperature T C (For example, iron T C The magnetization of a permanent magnet, which is less than 1043 Kelvin, is reasonably well described by the effect of spontaneous magnetization (further details on suitable materials for the magnets and yoke are discussed further below). The dependence can be described by Bloch's law (see Neil W. Ashcroft, N. David Mermin, "Solid State Physics", Brooks Cole, 1976) as follows: TIFF2024012118000003.tif12150Here, M(T) is the temperature-dependent magnetization, M(0) is the reference magnetization at zero Kelvin, T is the temperature, T C is the Curie temperature. Figure 15(A) shows the ratio T / T C and the ratio of the y-axis M(T) / M(0) Paramagnetic materials, which are usually used for magnetic yokes, are governed by different laws. For high magnetic fields and small temperatures ("small" relative to the Curie temperature), the temperature dependence is approximately described by the Langevin function L(x) (see "Solid State Physics" above): TIFF2024012118000004.tif10150 TIFF2024012118000005.tif6150Here, M(T) is the Bohr magneton μ B Temperature-dependent magnetization proportional to the Langevin function L(x) with independent variables including, B is the magnetic field, k B is the Boltzmann constant and T is temperature. Figure 15(B) shows the proportionality of magnetization M(T) as a function of temperature T for a range around room temperature that includes the typical temperature range of operation, where temperature is given in degrees Celsius (°C). Both ferromagnetic and paramagnetic materials fall outside of these descriptions as the temperature approaches or reaches the material's respective Curie temperature.

[0055] In the exemplary forms of the magnetic circuit assembly described herein, the permanent magnet is made of ferrite material. A temperature change from 25°C to 35°C will cause a decrease in magnetic field strength of 1.8%. In contrast, the yoke is made of iron oxide (mainly Fe2O3), and the above temperature change will cause a 5% decrease in magnetic permeability. In FIG. 1(B), an exemplary decrease in magnetic field Bz along the central axis cx due to temperature change is shown. Here, the dotted line (dashed line) shows the reference magnetic field (curve) 62 at a base temperature of 25°C, while a temperature increase of only 10K, i.e. to 35°C, will result in a decreased magnetic field (curve) 61, shown as a solid line in FIG. 1(B).

[0056] Conventional permanent magnet lenses can achieve accuracy within 1% to 5% of the target magnetic field strength due to the manufacturing range of the permanent magnets disposed in such systems. By using a temperature control assembly according to the present invention, this range can be reduced to accuracy within 0.1% to 0.5% of the target field, providing an order of magnitude less deviation from the desired magnetic field and therefore significantly better performance. In addition, the temperature control assembly can also be used to actively change and modify the magnetic field in the gaps and even change the optical properties of the magnetic lens.

[0057] 2 shows an example of an exemplary form of the temperature control element 31 arranged in the holder 32. The temperature control element 31 and the holder 32 are ring-shaped elements (see FIG. 2(A)) with a common central axis c2, which preferably coincides with the central axis cx of the lens assembly. The temperature control element is typically arranged in the immediate vicinity of the two or more permanent magnets 210, 211 and between both yoke elements 250, 251 (see FIG. 2(B)); it should be noted that the temperature control element may need to be arranged during the assembly of the lens, due to its rather encapsulated position; nevertheless, the temperature control element can also be added after the initial assembly, if appropriate technical solutions, such as partial disassembly, are used, or if the element is composed of replaceable modules inside the lens.

[0058] 3-5, in some embodiments of the invention, the temperature control element 31 may be composed of multiple sub-elements 330, 340, 350-353 arranged along or around a common axis c2, which may, for example, coincide with the central axis cx of the complete lens assembly. The sub-elements may be multiple layers 330 (FIG. 3), in which case the temperature control element is constructed as a stack. Alternatively, the sub-elements may be multiple sectors 340 (FIG. 4), in which case the temperature control element is constructed as a compound ring-like element. The sectors 350-354 may be composed of different materials with different thermal conductivities (FIG. 5); this allows for a temperature control element with varying thermal energy output or input, and thus local variations in magnetic flux density in the assembled temperature control element 31. Such variations may be associated with magnetic multipoles in the magnetic lens assembly, which may be used to intentionally introduce such azimuth dependence; this may be used, for example, to counteract permanent magnets that give the multipole-like feature. On the other hand, the selected regions may be intentionally kept empty.

[0059] In many configurations, symmetric lens assemblies are of particular importance. In a radially symmetric magnetic lens structure, each magnetic field contains an axial component and a radial component, i.e. TIFF2024012118000006.tif6150; in this regard, the radial component TIFF2024012118000007.tif6150 is of minor importance, and as a result, the axial component of the magnetic field TIFF2024012118000008.tif6150 is used for the lens effect. The strength 61, 62 of the axial component of the magnetic field at the position of the central axis cx is shown in FIG. 1(B) as a function of the ordinate (solid line 61 and dashed line 62); axial magnetic field Typical values ​​for the peak value of TIFF2024012118000009.tif6150 are of the order of 0.1 T in applications where the charged particles are electrons. As already mentioned, the magnetic circuit will generate two regions close to the gaps 290, 291 with (relatively) high magnetic field strength, which act as two consecutive magnetic lenses in the beam path 11 with well-defined focal lengths and optical aberrations. The magnetic coupling of the two lenses via the common yoke body 25 strongly reduces the effect of stray magnetic fields in any other region, but would otherwise be necessarily associated with permanent magnets in a particle lens of conventional layout.

[0060] In some embodiments of the invention, it may be advantageous to insert one or more temperature control elements in two or more spaces between the magnets and the yokes, thereby introducing an intentional asymmetry along the longitudinal axis into the assembly. FIG. 6(A) shows an example of a configuration with only one temperature control element arranged asymmetrically along the longitudinal axis, while FIG. 9(A) (see below) shows an example of another configuration with multiple temperature control elements arranged in different spaces - both of these configurations can create a thermal asymmetry. Such a configuration can create a temperature gradient in the heat-relevant parts along the axis cx. This can be used to cause localized changes in the two magnetic lenses and / or to counteract unintended inherent asymmetries of the magnets and / or yokes. FIG. 6(B) shows the effect of one example of a temperature gradient, i.e., the creation of an asymmetric effect on the magnetic field strength of the two magnetic lenses (curve 62 shows the case without temperature adjustment, while curve 63 shows an example of an asymmetric effect caused by an asymmetrically mounted temperature control element).

[0061] The multiple permanent magnets 210, 211 may be used in many suitable configurations, for example they may be preferably arranged in a stacked manner along the longitudinal axis of the system, although in some of these configurations multiple temperature control elements 31 may be used, which may be located between the multiple permanent magnets along the longitudinal axis of the lens.

[0062] Permanent magnets

[0063] The permanent magnets 210 and 211 function as a source of magnetic flux Φ in the magnetic circuit embodied in the magnetic circuit assembly 20 .

[0064] FIG. 7 shows a preferred form of permanent magnet 21 suitable for use as a component of a magnetic circuit assembly of a lens according to the present invention (e.g., as one of the permanent magnets 210, 211 of FIG. 1(A)). The magnet has a primary radial magnetization for a rotationally symmetric magnet. In FIG. 7, (A) is a schematic perspective view and (B) is a schematic cross-sectional view along the longitudinal axis c1 of magnet 21.

[0065] In many configurations, it may be useful for such magnets to be constructed from multiple sector portions, see Figs. 8(A)-(D), which show four exemplary variations of ring magnets 21 with net radial magnetization in their respective schematic cross-sectional views. Note that the components of the ring magnet are shown exploded in Figs. 8(B)-(D) for better clarity. The radial magnetization directions also provide preferred positions of yoke elements, i.e., inside and outside of such ring magnets, that take in magnetic flux from either pole of the magnet and direct it to the designed (intended) positions of the gaps 290, 291 between the yoke elements (see Fig. 1(A)). Each of the magnet elements will have its magnetization oriented mainly in the radial direction, as shown by the dashed arrows in Figs. 8(A)-(D), so that, for example, the "north" pole N is formed towards the inner space of the ring magnet, while the outside (of the ring magnet) has the "south" pole S of magnetization. Permanent magnet elements with radial magnetization as shown are commercially available and are made of ferromagnetic materials such as sintered NdFeB, SmCo5 or ferrite. The magnet elements 240, 241, 242 of the compound magnet of Figs. 8(B)-(D) are bonded together by gluing or clamping or other suitable means. The number of magnet elements forming each ring magnet can be any number, for example 1, 2, 3, 4, 6 or more, depending on the dimensions of the compound element (especially the height and radius) and the desired dimensions of the permanent magnet 21.

[0066] 7, in many forms, the permanent magnet 21 may be embodied as a ring-shaped piece and may include multiple layers of ring-shaped segment magnets 220 stacked along a common central axis c1. In such segmented magnets, each layer or segment contributes to the total magnetic flux of the magnet consisting of n layers. Part of TIFF2024012118000010.tif11150 Compose TIFF2024012118000011.tif6150.

[0067] Housing body

[0068] In many forms, the yoke body 25 also functions as the housing 12 of the lens 10. The yoke body is composed of an inner yoke element 250 and an outer yoke element 251, the inner yoke element 250 being 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 the temperature control element; the outer yoke element 251 may also be embodied in this case to have a cylindrically symmetric shape of height h1 with an aperture radius r2 and an outer radius r1 of 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 (FIG. 1(A)); in other words, the outer yoke includes a central body portion formed as a hollow cylinder that may be concentric with the hollow cylinder of the inner yoke element, and further has two end portions of a disk-like shape with a central hole. The hollow space of the yoke elements thus surrounds the beam passage 11 of radius r2 and height h1 along the longitudinal axis cx. The magnetic circuit gaps 290, 291 are provided between the axially outer end faces of the inner yoke element and the corresponding axially inner faces of the outer yoke element, 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, of the order of a few millimeters, and the height of the assembly is of the order of a few tens of millimeters. Due to their shape, the inner and outer yoke elements forming the housing body of the lens are able to enhance and focus the magnetic flux generated by the magnets. The outermost yoke element also acts as a shield against the magnetic flux in the radial and axial directions, since its spatial shape and material will concentrate the magnetic flux within the dimensions of radius r1 and height h1.

[0069] Electrical inlay (insert material)

[0070] According to a further aspect of the invention as shown in FIG. 9, the charged particle lens 10 may advantageously include a sleeve insert member or inlay 50 (FIG. 9(A)) that is inserted into the beam path 11 along the optical axis cx. Accordingly, the physical dimensions of the inlay are appropriately selected relative to the dimensions discussed above, such as within the lens radius r2 and height h1. The inlay may include a number of beam control elements 52-54, including one or several electrically active elements that are employed to generate an adjustable electric field 65 (dashed curve in FIG. 9(B)) that is superimposed on a magnetic field 61 (solid curve in FIG. 9(B)) in the beam path. The axial component (i.e. along the longitudinal direction) of the electric field E Z The strength of is 10 5 It will have typical values ​​of peak values ​​on the order of 1000 V / m.

[0071] In many forms of the inlay, the beam control elements 52-54 are generally ring-shaped components that serve as electrically active elements and are arranged in a stacked manner along a central axis c3, with their geometric axes oriented concentrically and parallel to the central axis cx of the lens. In many forms of the invention, it is useful for all control elements to have a common inner radius r2; so that they define a passage hole 55 that traverses the lens and serves as a channel for the charged particle beam 100 during operation of the charged particle lens. In addition, it may be useful to insert a smaller aperture 54 (see below) for beam calibration.

[0072] In the embodiment shown in Fig. 9(A), the beam control elements (plurality) are embodied with two Einzel lenses 52a, 52b and two multipole electrodes 53a, 53b, all made of a conductive material. For example, each of the multipole electrodes can be embodied as a composite metal ring, composed of a number of sections with equal arc lengths, e.g., without loss of generality, 4, 6 or 8 sections (see Fig. 11); their (radial) thickness is typically less than 2 mm and their length is between 5 mm and 20 mm. Furthermore, a conductive ring-shaped aperture 54 is preferably disposed between the two multipole electrodes 53a, 53b; this component is referred to herein as a "calibration aperture". The electrically active elements may preferably be connected to their own power supply units 722a, 722b, 723a, 723b as shown in FIG. 10, so that their electrostatic potentials are individually adjustable; in one variation, the power supplies may be combined in a common multi-channel power supply 70 providing individual supply voltages. The calibration apertures may be controlled by the power supply 70 or by a separate dedicated electrical control device 71. Finally, the electrically active elements are electrically isolated from each other and terminated at both ends by elements called field termination caps 51a, the electrical potential of which represents a "local earth" or reference point. The field termination caps serve to confine the electric field to the passage space of the inlay; thus, they provide a well-defined "field boundary" of the inlay with respect to the surrounding components (such as other particle-optical columns 400, see FIG. 14). Some spaces on the inlay mounting body 51 between the field termination caps and other electrical components may be electrically insulating, for example, by vacuum or filler material using a non-conductive, preferably voltage-resistant, material such as a ceramic.

[0073] In many forms of the invention, the various elements 52-54 of the inlay 50 are supported and held together by a mounting body 51 of hollow cylindrical shape (e.g., inner radius r3, outer radius r2, and height h1), which can typically be made of an electrically insulating material, e.g., ceramic or plastic; however, at least the portion 51a facing the charged particle beam can be covered with a conductive material and connected to a "drain" to avoid charging up. The electrode elements can be embodied, for example, as separate ring-shaped elements 52a, 52b, 53a, 53b, 54 joined and held together within the body, or as conductive coatings 51a formed on the inner circumferential surface of the ring body, each having a limited shape and area.

[0074] By means of the inlay, the precision of the optical properties, e.g. the focal length of the charged particle lens (limited by the precision of manufacture of the permanent magnets, the assembly precision and the limited adjustability by at least one temperature control element), can reach an accuracy of 1 ppm to 5 ppm above and below the target value - thus allowing "ultra-precise" tuning. Some embodiments of the invention may also include built-in correction means that can be used to overcome limitations related to, for example, magnet aging effects, since the electric field can be adjusted and controlled with precision in the ppm (parts per million) regime without resolution during use of the lens, i.e. "in situ tuning". Furthermore, the voltages of the beam control elements can be adjusted in combination with other optical and electrically active elements of the system to change the properties of the particle beam exposure apparatus 1, e.g. with respect to optical properties such as aberrations, image plane, etc.

[0075] FIG. 11 shows a cross-section of an example of a multipole electrode of an inlay. The multipole electrode includes a number of rods (or strips) 530 (partially circular in cross-section) that can be controlled with individual electric potentials by their respective external power supply units 70. Furthermore, a global offset voltage can be applied to make them behave as additional electrostatic lenses. By applying different voltages to the individual rods, various electrostatic field configurations of dipole, quadrupole or higher order can be realized in order to shape the particle beams intersecting at their respective transversal sections of the optical axis. For a typical application according to the configuration of FIG. 10, the voltages applied to the rods are typically of the order of up to several tens of volts. Such beam shaping can be used to compensate for errors due to imperfections in the optical system, such as magnetic inhomogeneities, mechanical manufacturing and / or assembly precision. In this regard, when a multipole is used as a dipole, it can correct the beam position relative to the optical axis c3, but its orientation in the plane defined by the X- and Y-axes (FIG. 11) can be any, provided that at least four different voltages are applied to these rods: +V1 (rods with (linear) hatching on the right side of the page), -V1 (rods with (linear) hatching on the left side of the page), +V2 (rods with checkerboard hatching on the top side of the page) and -V2 (rods with checkerboard hatching on the bottom side of the page). Furthermore, when a multipole is used as a quadrupole or higher order multipole, it can compensate for astigmatism or other higher order distortions by applying appropriate voltages to the individual rods in a similar manner to the dipole case.

[0076] It should be noted that any multipole electrode can be used as a (quasi-)static element or as a dynamic element, i.e. with a time-varying voltage, depending on the application. It should be understood by those skilled in the art that the above uses of beam control elements are described as exemplary applications and not as limitations on the functionality achievable by the present invention.

[0077] 10 and 12, as mentioned above, in some configurations of the invention, the inlay 50 may include a passive element 54, referred to as a "calibration aperture", that acts as a stop element to deflect (remove) stray portions of the particle beam 120. FIG. 12 shows an example of a calibration aperture in enlarged detail in longitudinal section. The calibration aperture includes a body 540 that encloses a calibration bore 541, which is an aperture having a small radius r4 along an axis c3. The aperture serves to limit the size of the beam 100 traversing the charged particle lens by absorbing the portion 120 of the beam traveling outside the aperture, so that only the portion 110 (of the beam inside the aperture) can pass through the aperture. In a preferred form of the invention, one of the upstream inlay elements, e.g., multipole electrode 53a, can vary the lateral position of the beam with respect to the longitudinal axis, e.g., by varying the voltage applied to selected electrodes of the multiple electrodes forming an electric dipole field. Multipoles can also be used for beam alignment. The charged particle lens 10 is advantageously configured to form a crossover xo at or near (e.g., 10 mm or less) the longitudinal location of the calibration aperture 54. Thus, the beam diameter is smallest near the aperture.

[0078] In many forms of the invention, particularly in particle beam devices used as multi-beam writing tools, such as single-column tool 1 or multi-column tool 40 (see below for the latter), the charged particle beam is split into a number of beamlets that can selectively pass through a pattern definition system 4, 43 without e or with f (FIG. 13) additional lateral deflection introduced by the pattern definition system. Such deflection is introduced to prevent (certain) beamlets from reaching the target and thus to define a discrete writing pattern. The deflected beamlets will not pass through the calibration bore 541, but will reach a region of the body 540 of the "calibration aperture" beside (outside) the calibration bore 541, where they will be absorbed; the absorption of the beam 120 will cause the generation of electric charge-up in the components, which can be removed, i.e. drained off, for example by an electrical connection of the beam aperture to a measuring device 714 that allows monitoring of the amount of absorbed beam (FIG. 10). The beamlets impinging on the "calibration aperture" also cause the transfer of thermal energy to the "calibration aperture" and, therefore, to the inlay elements surrounding it, and finally also to the magnetic lens assembly. This needs to be taken into account by at least one temperature control element for tuning the magnetic lens.

[0079] Lithography Equipment

[0080] FIG. 13 is a schematic longitudinal cross-sectional view of an example of a single-column writer tool 1. The tool includes an exemplary embodiment of the lens of the present invention; for example, the objective lens 10 of the tool includes a charged particle lens according to an embodiment of the present invention. The writer tool uses a charged particle beam, which may be electrons or ions (e.g., positively charged ions). The writer tool 1 includes a vacuum housing 480 for the multi-column charged particle optics, a base member 470 on which the multi-column charged particle optics 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 write writer tool, is mounted using a suitable manipulation system. The target, which may for example include a resist layer, can then be exposed by the writer's charged particle beam.

[0081] This form of single-column optical system preferably comprises a central axis c5, an illumination optical system 3 including a charged particle source 7, a condenser 8 which supplies a wide, telecentric charged particle beam ib to a pattern definition system 4 (which is adapted to pass the beam only through a number of apertures which define the shape of the sub-beams ("beamlets") passing through said apertures (beam shaping device), and charged particle projection optical system 5 which typically performs demagnification and also provides energy (the projection optical system 5 is composed of a number of charged particle lenses arranged in succession, which preferably include electrostatic and / or magnetic lenses and possibly other particle-optical devices). 13, the projection optics include, for example, a first charged particle lens 9, e.g. an electrostatic immersion lens, while a second lens 10, which is located downstream of the first lens, is embodied using a charged particle lens according to one embodiment of the invention (e.g. FIG. 9(A)). Within the charged particle lens 10, a "calibration aperture" 54 is embodied, as symbolically shown; as mentioned above, a certain portion f of the beam deflected by the pattern definition device 4 is absorbed, while another portion e traverses the optical column unhindered to expose the pattern onto the target 450.

[0082] The pattern definition device 4 serves to form from the particle beam a number of so-called beamlets which contain information of the pattern to be transferred to the target. The structure, operation and data processing of the pattern definition device 4 and its controller 404 are disclosed in the applicant's US 9,443,699 and US 9,495,499, the contents of which are incorporated herein by reference.

[0083] 14(A) and 14(B) show an example of a multi-column writer tool 40. The tool 40 includes, in each column, an instance of an exemplary embodiment of the lens of the present invention; for example, a charged particle lens according to an embodiment of the present invention as an objective lens in the tool. The writer tool uses multiple charged particle beams, which may be electrons or ions (e.g., positively charged ions). As can be seen in FIG. 14(A), which shows a schematic longitudinal cross-section of the multi-column writer tool 40, the writer tool 40 includes a vacuum housing 48 for the multi-column charged particle optics, a base member 47 on which the multi-column charged particle optics is mounted. On top of the base of an XY stage 46, for example a laser interferometer controlled air-bearing vacuum stage, a target 45, preferably a mask for lithography purposes or a silicon wafer in the case of a direct write writer tool, is mounted using a suitable manipulation system. The target, which may for example include a resist layer, can then be exposed by the charged particle beam of the writer.

[0084] This form of multi-column optical system includes a number of sub-columns 400 (the number of columns shown has been reduced in the figure for better clarity and is representative of the much larger number of columns present in a multi-column device in an actual implementation), preferably with the sub-columns having the same configuration and arranged with their parallel axes c5 juxtaposed. Each sub-column comprises an illumination system 42 including a charged particle source 41 and supplying a wide, telecentric charged particle beam to a pattern definition system 43 adapted to pass the beam only through a number of apertures that define the shape of the sub-beams ("beamlets") passing through said apertures (beam shaping devices), and typically demagnifying and also energizing charged particle projection optics 44 consisting of a number of successively arranged charged particle lenses, which preferably include electrostatic and / or magnetic lenses, possibly other particle-optical devices. In the embodiment shown in FIG. 14, the projection optics comprises, for example, a first charged particle lens 44a, for example an electrostatic immersion lens, while the second lens 10, which is arranged downstream of the first lens, is embodied using a charged particle lens (for example FIG. 1(A)) according to one embodiment of the invention.

[0085] Fig. 14 shows in a detailed view an example of lenses 10 used as second lenses and their supporting elements. Each second lens 10 of the sub-columns is preferably attached to a reference plate 49, which is attached to the column base plate 47 or to a specific flange 48 of the vacuum chamber by suitable fastening means 49b. The reference plate 49 is manufactured from a suitable base material with low thermal expansion, such as a ceramic material based on silicon oxide or aluminum oxide, which has the advantages of low weight, high elastic modulus and high thermal conductivity, and may be suitably covered, at least in its relevant parts, with a conductive coating to avoid charging (by draining static charges). Furthermore, the reference plate 49 may include apertures 49a that overlap (match) the beam path 11 of the lens 10 of each sub-column.

[0086] All or part of the above embodiments can be described as the following supplementary notes, but are not limited thereto. [Appendix 1] A charged particle lens configured to modify a charged particle beam of a charged particle optical system. the lens extends primarily along a longitudinal axis and includes a passage space for permitting the passage of a charged particle beam; The lens is at least one permanent magnet, and -Yoke body a magnetic circuit assembly including: The yoke body is composed of at least two yoke elements; of the at least two yoke elements, a first yoke element constitutes an inner yoke shell arranged to surround the passage space, and a second yoke element constitutes an outer yoke shell arranged to surround the inner yoke shell; the at least two yoke elements are arranged around the longitudinal axis and include a highly permeable material; the at least one permanent magnet is disposed between the at least two yoke elements and around the inner yoke shell; the at least one permanent magnet includes a permanent magnet material having two magnetic poles magnetically oriented toward the respective yoke elements; In the magnetic circuit assembly, the at least one permanent magnet and the yoke body 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 coming from the at least one permanent magnet through the yoke body, and induce a magnetic field in the at least two gaps that reaches inwardly into the passage space; the charged particle lens comprises a temperature control assembly including at least one temperature control element disposed in the yoke body; The temperature control assembly is configured to control and / or actively vary a temperature of at least a portion of at least one component of the magnetic circuit assembly using the at least one temperature control element to introduce heat to and / or remove heat from the component to control and / or modify magnetic flux in the magnetic circuit. [Appendix 2] In the above-mentioned charged particle lens, particularly as described in appendix 1, The at least one temperature control element includes at least one of a heating device capable of generating heat within the magnetic circuit assembly and a cooling device powered by a medium capable of removing and transporting heat from the magnetic circuit assembly. [Appendix 3] In the above-mentioned charged particle lens, particularly as described in appendix 1 or 2, the charged particle lens has a generally rotationally symmetric shape along the longitudinal axis; Components of the magnetic circuit assembly, namely: at least one permanent magnet, -Yoke body, and At least one temperature control element is disposed concentrically about the longitudinal axis. [Appendix 4] In the above-mentioned charged particle lens, particularly as described in appendix 3, The components of the magnetic circuit assembly have a basic shape corresponding to a hollow cylinder or a hollow polygonal prism shape. [Appendix 5] In the charged particle lens described above, particularly in any one of appendices 1 to 4, The at least one temperature control element comprises a thermal interface to an exterior of the charged particle lens configured to transport heat in and / or out. [Appendix 6] In the above-mentioned charged particle lens, particularly as described in appendix 5, The thermal interface is configured to transfer heat in and / or out through suitable holes formed in the outer yoke shell. [Appendix 7] In the charged particle lens described above, particularly in any one of appendices 1 to 6, The temperature control assembly includes two or more temperature control elements positioned at different locations associated with different components of the magnetic circuit assembly, and is configured to create a temperature gradient along the longitudinal axis in the magnetic circuit assembly. [Appendix 8] In the charged particle lens described above, particularly in any one of appendices 1 to 7, At least one temperature control element includes two or more sub-elements configured to form an azimuthal temperature gradient to enable the magnetic lens to have different azimuthally varying magnetic flux densities and therefore azimuthally varying magnetic fields about the longitudinal axis and is configured to operate at least in part like a magnetic multipole. [Appendix 9] In the above-mentioned charged particle lens, particularly as described in appendix 8, The sub-elements are formed as sectors of an annularly shaped temperature control element. [Appendix 10] In the above-mentioned charged particle lens, particularly as described in appendix 8 or 9, The sub-elements comprise respective thermal interfaces to the exterior of the charged particle lens configured to transport heat in and / or out. [Appendix 11] In the above-mentioned charged particle lens, particularly as described in appendix 10, The thermal interfaces of the sub-elements are configured to transport heat in and / or out through suitable holes formed in the outer yoke shell. [Appendix 12] In the charged particle lens described above, particularly in any one of appendices 1 to 11, The second yoke element constitutes a housing body for the lens assembly; the housing body encloses the other elements of the lens assembly, including all other yoke elements. [Appendix 13] In the charged particle lens described above, particularly in any one of appendices 1 to 12, The at least one permanent magnet has a magnetization oriented substantially radially. [Appendix 14] In the charged particle lens described above, particularly in any one of appendices 1 to 13, The at least one permanent magnet is composed of at least two sub-elements, namely: · segmented according to two or more layers stacked along a vertical axis; and / or Divided into two or more sectors arranged around a vertical axis. [Appendix 15] In the above-mentioned charged particle lens, particularly as described in appendix 14, At least one temperature control element is disposed between each two of said at least two sub-elements. [Appendix 16] The charged particle lens according to any one of the above, particularly appendices 1 to 15; a sleeve insert member inserted into the passage space along the longitudinal axis; an electromagnetic lens. The sleeve insert member surrounds a beam passage having a radius smaller than a radius of a passage space of the charged particle lens and extends along a longitudinal axis; The sleeve insert member includes a mount body having at least one conductive portion and at least one conductive electrode element; the at least one electrode element is configured to have an electric potential applied to it via a power source relative to an electric potential of the at least one conductive portion to generate an electrostatic field in the beam path; the (at least one) electrode element is configured to form a particle-optical lens together with a magnetic field in the beam path in at least one of the at least two gaps; The focal length of the charged particle optical lens is adjustable by modifying the electrical potential applied to the electrode elements. [Appendix 17] In the electromagnetic lens described above, particularly in appendix 16, the inner yoke shell extends along the longitudinal axis and circumferentially surrounds the sleeve insert member; The at least two gaps in the magnetic circuit are (respectively) located at either axial end of the inner yoke shell; each gap generates a defined magnetic field that extends inwardly into the space of the beam passage; and the electrostatic field generated by at least one of the multiple electrode elements of the sleeve insert member is configured to at least partially overlap with the magnetic field. [Appendix 18] In the electromagnetic lens described above, particularly as described in appendix 16 or 17, At least one of the plurality of electrode elements includes an electrostatic multipole electrode; the electrostatic multipole electrode includes a plurality of sub-electrodes circumferentially and uniformly spaced (uniformly) around the longitudinal axis; the plurality of sub-electrodes are connectable to a multi-channel power supply unit which individually supplies a potential to each sub-electrode. [Appendix 19] In the electromagnetic lens described above, particularly in any one of appendices 16 to 18, The plurality of electrode elements includes a beam aperture element forming a limiting aperture having a defined (predetermined) radius about said longitudinal axis; the limiting aperture is configured to limit a lateral width of a charged particle beam propagating along the longitudinal axis; The beam aperture element is connected to a current measuring device configured to measure an amount of the charged particle beam absorbed in the beam aperture element. [Appendix 20] In the electromagnetic lens described above, particularly in any one of appendices 16 to 19, The longitudinal axis of the sleeve insert member coincides with the longitudinal axis of the charged particle lens. [Supplementary Note 21] A charged particle optical device comprising the charged particle lens according to any one of Supplements 1 to 15 or the electromagnetic lens according to any one of Supplements 16 to 20. the charged particle optical device is configured to affect a charged particle beam of the charged particle optical device propagating through the charged particle lens along a longitudinal axis of the charged particle lens; The charged particle lens is part of a particle-optical system of the charged particle optical device. [Supplementary Note 22] In the charged particle optical apparatus described above, particularly as described in Supplementary Note 21, the charged particle optical device is configured as a multi-column system including a plurality of particle-optical columns; Each column is configured to use a respective particle beam and includes a respective particle-optical system that includes a respective instance of a charged particle lens or an electromagnetic lens.

[0087] Within the scope of the entire disclosure of the present invention (including the claims and drawings), modifications and adjustments of the embodiments are possible based on the basic technical ideas. Furthermore, within the scope of the entire 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 various modifications and corrections that a person skilled in the art would be able to make in accordance with the entire disclosure including the claims and drawings and the technical ideas of the present invention. In particular, with regard to the numerical ranges described in this specification, any numerical value or subrange included in the range should be interpreted as being specifically described even if not otherwise specified.

[0088] Furthermore, the reference numerals in the drawings attached in the claims are intended solely to aid in the understanding of the invention, and are not intended to limit the invention to the embodiments and examples shown.

[0089] Furthermore, the entire contents of each of the above references are hereby incorporated by reference. [Explanation of symbols]

[0090] 1. Charged Particle Optical System 10 Charged particle lens 11 Passage space 12 Housing body 20 Magnetic circuit assembly 21 Permanent magnets 25 Yoke body 30 Temperature Control Assembly 31 Temperature Control Elements 33 Thermal (temperature control) interface 40 Multi-column System 50 Sleeve insert member 51 (Inlay) Mounting body 53 Electrostatic Multipole Electrode 54 Beam Aperture Element 55 Beam Passage 61 Magnetic Field 65 Static Electric Field 70 Power supply 71 Current measuring device 100 Charged Particle Beam 210, 211 Permanent magnet materials 220 layers 240 sectors 250 Inner York Shell 251 Outer York Shell 290, 291 Gap Sectors 350 and 351 530 Sub-electrode (or rod) 540 Limited Aperture cx, c2, c3 Vertical axis (or central axis)

Claims

1. A charged particle lens configured to correct the charged particle beam of a charged particle optical system (1), The lens is provided with a passage space (11) that extends mainly along the vertical axis (cx) and allows the passage of a charged particle beam (100). The aforementioned lens is, - At least one permanent magnet (21; 210, 211), and • York body (25; 250, 251) Includes a magnetic circuit assembly (20) including, The yoke body (25) is composed of at least two yoke elements (250, 251), of which the first yoke element constitutes an inner yoke shell (250) arranged to surround the passage space (11), and the 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 magnetic permeable material; The at least one permanent magnet (21) is positioned between the at least two yoke elements and around the inner yoke shell, and the at least one permanent magnet includes a permanent magnet material (210, 211) whose two magnetic poles are magnetically oriented toward each of the 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 surfaces 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 (61) in the at least two gaps that reaches inward into the passage space, and The charged particle lens comprises a temperature control assembly (30) including at least one temperature control element (31) disposed on the yoke body. The temperature control assembly is configured to control and / or actively change the temperature of at least a portion of at least one component of the magnetic circuit assembly (20) for the purpose of controlling and / or modifying the magnetic flux in the magnetic circuit, using the at least one temperature control element (31) to introduce heat into and / or remove heat from the component. A charged particle lens characterized by the following features.

2. In the charged particle lens according to claim 1, The at least one temperature control element includes at least one heating device capable of generating heat within the magnetic circuit assembly (20), and a cooling device operated by a medium capable of removing and transporting heat from the magnetic circuit assembly (20). A charged particle lens characterized by the following features.

3. In the charged particle lens according to claim 1, The charged particle lens has a shape that is rotationally symmetrical overall along the vertical axis (cx). The components of the magnetic circuit assembly (20), namely, - At least one permanent magnet (21), - Yoke body (25), and - At least one temperature control element (31) It is arranged concentrically with the vertical axis. A charged particle lens characterized by the following features.

4. In the charged particle lens according to claim 3, The components of the magnetic circuit assembly (20) have a basic shape or a hollow polygonal prism shape corresponding to a hollow cylinder. A charged particle lens characterized by the following features.

5. In the charged particle lens according to claim 1, The at least one temperature control element (31) comprises a thermal interface (33) to the outside of the charged particle lens, configured to transport heat to the inside and / or outside. A charged particle lens characterized by the following features.

6. In the charged particle lens according to claim 5, The thermal interface (33) is configured to transport heat to the inside and / or outside through appropriate holes formed in the outer yoke shell. A charged particle lens characterized by the following features.

7. In the charged particle lens according to claim 1, The temperature control assembly includes two or more temperature control elements (31) located at multiple different locations, each associated with multiple different components of the magnetic circuit assembly (20), and is configured to form a temperature gradient along the vertical axis (c2) in the magnetic circuit assembly. A charged particle lens characterized by the following features.

8. In the charged particle lens according to claim 1, At least one temperature control element (31) includes two or more sub-elements configured to form an azimuth temperature gradient, which enables the magnetic lens to have different azimuth-changing magnetic flux densities and therefore an azimuth-changing magnetic field around the vertical axis (c2), and is configured to operate at least partially like a magnetic multipole. A charged particle lens characterized by the following features.

9. In the charged particle lens according to claim 8, The aforementioned sub-elements are formed as sectors (350, 351) of a ring-shaped temperature control element. A charged particle lens characterized by the following features.

10. In the charged particle lens according to claim 8, The sub-element comprises a separate thermal interface (33) to the outside of the charged particle lens, configured to transport heat to and from the inside and / or outside. A charged particle lens characterized by the following features.

11. In the charged particle lens according to claim 10, The thermal interface of the sub-element is configured to transport heat to the inside and / or outside through appropriate holes formed in the outer yoke shell. A charged particle lens characterized by the following features.

12. In the charged particle lens according to claim 1, The second yoke element (251) constitutes the 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 the following features.

13. In the charged particle lens according to claim 1, The at least one permanent magnet (21) has a magnetization that is substantially oriented in the radial direction. A charged particle lens characterized by the following features.

14. In the charged particle lens according to claim 1, The aforementioned at least one permanent magnet (21) is composed of at least two sub-elements, that is, - The data is segmented according to two or more layers (220) stacked along the vertical axis (c1); and / or - It is divided into two or more sectors (240) arranged around the vertical axis (c1). A charged particle lens characterized by the following features.

15. In the charged particle lens according to claim 14, At least one temperature control element (31) is positioned between each of the two sub-elements. A charged particle lens characterized by the following features.

16. A charged particle lens according to any one of claims 1 to 15, A sleeve insert member (50) inserted into the passage space (11) along the vertical axis (cx) and An electromagnetic lens including, The sleeve insert member (50) surrounds the beam passage (55) having a radius (r3) smaller than the radius (r2) of the passage space (11) of the charged particle lens, and extends along the vertical axis (c3). The sleeve insert member (50) includes a mount body (51) having at least one 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 electrical potential is applied via a power source (70) to the electrical potential of the at least one conductive portion (51a) in order to generate an electrostatic field (65) in the beam passage. The electrode element is configured to form a particle optical lens in at least one of the at least two gaps (290, 291) together with the magnetic field (61) in the beam passage (55). The focal length of the charged particle optical lens can be adjusted by modifying the electrical potential applied to the electrode element. An electromagnetic lens characterized by the following features.

17. In the electromagnetic lens according to claim 16, The inner yoke shell (250) extends along the vertical axis (c3) and surrounds the sleeve insert member (50) in the circumferential direction. The at least two gaps (290, 291) of the magnetic circuit are located at either axial end of the inner yoke shell; each gap generates a defined magnetic field (61) that extends inward 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 the magnetic field. An electromagnetic lens characterized by the following features.

18. In the electromagnetic lens according to claim 16, At least one of the multiple electrode elements includes an electrostatic multipole electrode (53), the electrostatic multipole electrode (53) includes a plurality of auxiliary electrodes (530) arranged at regular intervals around the vertical axis (c3) along the circumferential direction, and the plurality of auxiliary electrodes are connectable to a multi-channel power supply unit (723) that supplies potential to each auxiliary electrode individually. An electromagnetic lens characterized by the following features.

19. In the electromagnetic lens according to claim 16, The multiple electrode elements include a beam aperture element (54) that forms a restricting aperture (540) having a radius (r4) defined around the vertical axis (c3). The limiting aperture is configured to limit the width of the charged particle beam (100) propagating along the vertical axis, and The beam aperture element is connected to a current measuring device (71) configured to measure the amount of charged particle beam absorbed in the beam aperture element. An electromagnetic lens characterized by the following features.

20. In the electromagnetic lens according to claim 16, The vertical axis (c3) of the sleeve insert member (50) coincides with the vertical axis (cx) of the charged particle lens. An electromagnetic lens characterized by the following features.

21. A charged particle optical apparatus comprising a charged particle lens according to any one of claims 1 to 15, The charged particle optical apparatus is configured to influence the charged particle beam (e, f) of the charged particle optical apparatus as it propagates through the charged particle lens along the vertical axis (cx) of the charged particle lens. The charged particle lens is part of the particle optics system (3, 5) of the charged particle optical apparatus. A charged particle optical device characterized by the following:

22. In the charged particle optical apparatus according to claim 21, The charged particle optical apparatus is configured as a multi-column system (40) including a plurality of particle optical columns. Each column is configured to use its respective particle beam and includes its respective particle optics system, which includes its respective configuration of charged particle lenses. A charged particle optical device characterized by the following:

23. A charged particle optical apparatus comprising an electromagnetic lens as described in Claim 16, The charged particle optical apparatus is configured to influence the charged particle beam (e, f) of the charged particle optical apparatus as it propagates through the charged particle lens along the vertical axis (cx) of the charged particle lens. The electromagnetic lens is part of the particle optics system (3, 5) of the charged particle optics apparatus. A charged particle optical device characterized by the following:

24. In the charged particle optical apparatus according to claim 23, The charged particle optical apparatus is configured as a multi-column system (40) including a plurality of particle optical columns. Each column is configured to use its respective particle beam and includes its respective particle optics system, which includes its respective configuration of electromagnetic lenses. A charged particle optical device characterized by the following:

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