Magnetic lens

Abstract

The present invention provides a magnetic lens, which can be applied to the field of magnetic lens technology. The magnetic lens comprises: a plurality of permanent magnets arranged coaxially; wherein each permanent magnet comprises an annular support and at least one sub-magnet, the structure of the annular support comprises a plurality of cavities, and at least one sub-magnet is respectively filled in at least one cavity of the plurality of cavities; the plurality of permanent magnets are used to generate a first magnetic field, and the first magnetic field acts on a particle beam injected into the inner ring area of ​​the annular support.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic lenses, and in particular to a magnetic lens. Background Art

[0002] The magnetic lens can generate a rotationally symmetric magnetic field, so that the electron beam can be focused or deflected due to the Lorentz force. The assembly accuracy and magnetism of the magnetic lens will directly affect the focusing accuracy of the electron beam. Due to the large structural size and closed-loop design, the traditional electromagnetic coil magnetic lens is difficult to assemble in some compact equipment and engineering application environments with specific spatial structure restrictions.

[0003] For electromagnetic coil magnetic lenses, it is difficult to achieve miniaturization of the equipment. The smaller the size of the electromagnetic coil, the larger the working current is required to generate the excitation field under the working conditions required by the magnetic lens. The large working current will bring high power consumption and a series of thermal management problems. Therefore, it is necessary to set up a coil water cooling or air cooling device. As part of the lens system, the coil cooling device will occupy more space of the magnetic lens body, and an external power supply is required to assist in the heat dissipation of the device. For permanent magnet magnetic lenses or multi-pole lenses, there are problems such as difficult assembly and poor adjustability. Summary of the invention

[0004] In view of the above problems, the present invention provides a magnetic lens.

[0005] According to a first aspect of the present invention, a magnetic lens is provided, comprising: a plurality of permanent magnets arranged coaxially; wherein each permanent magnet comprises an annular support and at least one sub-magnet, the structure of the annular support comprises a plurality of cavities, at least one sub-magnet is respectively filled in at least one cavity of the plurality of cavities; the plurality of permanent magnets are used to generate a first magnetic field, and the first magnetic field acts on a particle beam injected into an inner ring area of ​​the annular support.

[0006] According to an embodiment of the present invention, with the central axis of the annular bracket as the symmetry axis, the multiple cavities of each annular bracket are symmetrically distributed on a plane perpendicular to the symmetry axis, and the multiple cavities of each annular bracket extend along a first direction, which is parallel to the extension direction of the central axis.

[0007] According to an embodiment of the present invention, the plurality of permanent magnets can rotate counterclockwise or clockwise on a plane perpendicular to the first direction.

[0008] According to an embodiment of the present invention, at least one sub-magnet includes at least one first sub-magnet; wherein each first sub-magnet is simultaneously filled in the respective cavities of at least two permanent magnets among the plurality of permanent magnets, so that the at least two permanent magnets are connected to each other.

[0009] According to an embodiment of the present invention, at least two permanent magnets include a first permanent magnet and a second permanent magnet adjacent to each other in a first direction, and the first permanent magnet and the second permanent magnet can be relatively displaced relative to each other in the first direction; at least one sub-magnet also includes at least one second sub-magnet, and each second sub-magnet is only arranged in the cavity of one permanent magnet; the magnetic pole of the second sub-magnet in the first permanent magnet close to one side of the second permanent magnet is the first magnetic pole, and the magnetic pole of the second sub-magnet in the second permanent magnet close to one side of the first permanent magnet is the second magnetic pole, and the first magnetic pole is opposite to the second magnetic pole.

[0010] According to an embodiment of the present invention, the first sub-magnet includes a protruding structure in a second direction intersecting the first direction, and the protruding structure is located between the first permanent magnet and the second permanent magnet to limit the range of relative displacement of the first permanent magnet and the second permanent magnet relative to each other.

[0011] According to an embodiment of the present invention, at least two permanent magnets include a third permanent magnet and a fourth permanent magnet, the outer diameter of the third permanent magnet is smaller than the inner diameter of the fourth permanent magnet, and the third permanent magnet can perform relative displacement relative to the fourth permanent magnet within the inner ring area of ​​the annular bracket of the fourth permanent magnet; the first sub-magnet includes two filling parts and a connecting part connecting the two filling parts; the two filling parts are respectively filled in the respective cavities of the third permanent magnet and the fourth permanent magnet, so that the third permanent magnet and the fourth permanent magnet are connected via the connecting part, and the connecting part is also used to limit the range of relative displacement of the third permanent magnet relative to the fourth permanent magnet within the inner ring area of ​​the annular bracket of the fourth permanent magnet.

[0012] According to an embodiment of the present invention, the cross-sectional shape of the cavity in a plane includes a square, a parallelogram, a trapezoid or a prism, and the cross-sectional shape of the sub-magnet in a plane is the same as that of the cavity.

[0013] According to an embodiment of the present invention, the multiple cavities of each annular bracket include a first cavity and a second cavity, the first cavity and the second cavity are alternately arranged on a plane, the first cavity is filled with sub-magnets, and the second cavity is a cavity.

[0014] According to an embodiment of the present invention, the magnetic lens also includes: an electromagnetic coil wound around an annular bracket on the outer surface of an annular bracket in a clockwise or counterclockwise direction, the electromagnetic coil is used to generate a second magnetic field, and the superimposed magnetic field formed by the first magnetic field and the second magnetic field is used to process the particle beam injected into the inner ring area.

[0015] According to an embodiment of the present invention, by making an annular bracket and setting a cavity on the annular bracket to install at least one sub-magnet, the difficulty of assembling the permanent magnet is reduced. On this basis, the magnetization direction of the sub-magnet set in each cavity can be changed, so that the magnetic field distribution and magnetic field strength of the permanent magnet in the first direction can be flexibly adjusted. Therefore, by using adjustable sub-magnets as permanent magnet components, the magnetic field of the magnetic lens can be flexibly and accurately adjusted, so as to achieve the purpose of optimizing the focusing of the electron beam. In addition, compared with a magnetic lens with a fixed structure, the magnetic lens of the present invention allows the user to adjust the magnetic field strength and distribution according to specific application requirements, providing higher flexibility and better cost-effectiveness.

[0016] According to an embodiment of the present invention, the magnetic lens of the present invention can better adapt to compact or irregular assembly spaces, and is particularly suitable for applications that need to be assembled in a compact and narrow structure where the space is fixed, or integrated into a fixed electronic optical device or test frame, thereby simplifying the assembly process and reducing maintenance costs.

[0017] According to the embodiments of the present invention, the magnetic lens of the present invention can adjust the magnetic field without using an electromagnetic coil, and has a lower demand for cooling and assembly space, thereby improving the integration and reliability of the magnetic lens, reducing the volume of the magnetic lens, and helping to achieve compact miniaturized equipment. As a result, the permanent magnet, as a "passive" unit, has controllable residual magnetism, and can generate the required field distribution with a very small volume, avoiding the heat problem and space occupation problem caused by the energization of the electromagnetic coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0019] Figure 1A A schematic diagram of a magnetic lens according to an embodiment of the present invention is shown.

[0020] Figure 1B A schematic diagram of a Qth permanent magnet with unfilled sub-magnets according to an embodiment of the present invention is shown.

[0021] Figure 1C A cross-sectional view of a Qth permanent magnet filled with sub-magnets according to an embodiment of the present invention is shown.

[0022] Figure 1D A pictorial diagram of a permanent magnet with filled sub-magnets according to an embodiment of the present invention is shown.

[0023] Figure 1E Schematic diagrams showing sub-magnets of various shapes according to embodiments of the present invention.

[0024] Figure 1FA schematic diagram of a ring-shaped bracket with a fixing structure according to an embodiment of the present invention is shown.

[0025] Figure 1G A schematic diagram of a permanent magnet with a fixed structure according to an embodiment of the present invention is shown.

[0026] Figure 2 A schematic diagram showing the rotation of a permanent magnet according to an embodiment of the present invention is shown.

[0027] Figure 3 A schematic diagram of permanent magnets connected via a first sub-magnet according to an embodiment of the present invention is shown.

[0028] Figure 4 A schematic diagram showing a protruding structure of a sub-magnet according to an embodiment of the present invention.

[0029] Figure 5A A schematic diagram of a third permanent magnet and a fourth permanent magnet according to an embodiment of the present invention is shown.

[0030] Figure 5B FIG. 1 is a perspective view in the third direction showing the relative displacement of the third permanent magnet and the fourth permanent magnet according to an embodiment of the present invention.

[0031] Figure 5C A front view showing the relative displacement of the third permanent magnet and the fourth permanent magnet according to an embodiment of the present invention is shown.

[0032] Figure 6 A schematic diagram of a magnetic lens array according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0033] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0034] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0035] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0036] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0037] According to an embodiment of the present invention, the design of the permanent magnet magnetic lens focuses on how to adapt to the focusing and manipulation requirements of the electron beam by configuring the magnetic field distribution, such as the need to consider the magnetic field strength and uniformity, etc. In addition, there are special requirements for the manufacturing and processing technology of permanent magnetic materials to ensure that the magnetic lens can operate with high precision and high stability. In addition, the design of the magnetic lens also includes designing a magnetic circuit component, namely at least one permanent magnet and a yoke body composed of at least a high magnetic permeability component. Based on this, the structure of the permanent magnet magnetic lens is complex, and it is difficult to realize a permanent magnet magnetic lens with an adjustable magnetic field.

[0038] In view of this, the present invention provides an open-loop permanent magnet magnetic lens with a simplified structure and easy adjustment. Compared with the design using fixed permanent magnets, the magnetic lens of the present invention is more suitable for specific shapes and compact designs, and can provide high-precision magnetic field control means to improve the focusing and control accuracy of the electron beam, help to achieve large-scale and high-efficiency electron beam mask exposure and meet the needs of large-scale semiconductor wafer manufacturing, simplify the manufacturing and maintenance processes, and help reduce the total cost and operational complexity of the magnetic lens system.

[0039] Figure 1A A schematic diagram of a magnetic lens according to an embodiment of the present invention is shown.

[0040] like Figure 1A As shown, the magnetic lens of this embodiment includes: a plurality of permanent magnets 100-1...100-Q coaxially arranged along the central axis AX, where Q is an integer greater than 1. Each permanent magnet includes an annular support and at least one sub-magnet.

[0041] Taking the Qth permanent magnet 100-Q as an example, Figure 1B 1 shows a schematic diagram of a Q-th permanent magnet 100-Q of an unfilled sub-magnet according to an embodiment of the present invention, Figure 1C 1 shows a cross-sectional view of a Q-th permanent magnet 100-Q filled with sub-magnets according to an embodiment of the present invention, Figure 1DFIG. 2 shows a physical picture of a permanent magnet filled with sub-magnets according to an embodiment of the present invention. Figure 1B and Figure 1C As shown, the structure of the annular bracket 110-Q of the Qth permanent magnet 100-Q includes a frame 111-Q and a plurality of cavities 112-Q. The plurality of cavities 112-Q of the annular bracket 110-Q extend along a first direction X, and the first direction X is parallel to the extension direction of the central axis AX. For example, the plurality of cavities 112-Q may penetrate the frame 111-Q in the first direction X. The plurality of cavities 112-Q are distributed in a second direction Y and a third direction Z that intersect (for example, perpendicularly) with the first direction X, and the second direction Y and the third direction Z intersect (for example, perpendicularly) with each other. For example, with the central axis AX of the annular bracket as the axis of symmetry, the plurality of cavities 112-Q of the annular bracket 110-Q are symmetrically distributed on a plane perpendicular to the axis of symmetry (i.e., a plane parallel to the second direction Y and the third direction Z). The symmetry here may refer to central symmetry or axial symmetry, which is not limited here.

[0042] At least one sub-magnet 120-Q is respectively filled in at least one cavity 112-Q in the plurality of cavities 112-Q. The sub-magnets arranged in the permanent magnet generate a magnetic field distributed along the central axis AX. On this basis, the plurality of permanent magnets 100-1...100-Q are used to generate a first magnetic field, and the first magnetic field acts on the particle beam injected into the inner ring area IS of the annular bracket of the plurality of permanent magnets 100-1...100-Q. It can be understood that the annular bracket itself is an annular structure, and has an annular effective aperture area inside the annular bracket that allows the particle beam to pass through, and this effective aperture area corresponds to the inner ring area IS of the annular bracket.

[0043] According to an embodiment of the present invention, by making an annular bracket and setting a cavity on the annular bracket to install at least one sub-magnet, the difficulty of assembling the permanent magnet is reduced. On this basis, the magnetization direction of the sub-magnet set in each cavity can be changed, so that the magnetic field distribution and magnetic field strength of the permanent magnet in the first direction X can be flexibly adjusted. Therefore, by using adjustable sub-magnets as permanent magnet components, the magnetic field of the magnetic lens can be flexibly and accurately adjusted, so as to achieve the purpose of optimizing the focusing of the electron beam. In addition, compared with a magnetic lens with a fixed structure, the magnetic lens of the present invention allows the user to adjust the magnetic field strength and distribution according to specific application requirements, providing higher flexibility and better cost-effectiveness.

[0044] According to an embodiment of the present invention, the magnetic lens of the present invention can better adapt to compact or irregular assembly spaces, and is particularly suitable for assembly applications in compact and narrow structures with fixed spaces, or integrated into fixed electronic optical equipment or test frames, thereby simplifying the assembly process and reducing maintenance costs.

[0045] According to the embodiments of the present invention, the magnetic lens of the present invention can adjust the magnetic field without using an electromagnetic coil, and has a lower demand for cooling and assembly space, thereby improving the integration and reliability of the magnetic lens, reducing the volume of the magnetic lens, and helping to achieve compact and miniaturized equipment. As a result, the permanent magnet, as a "passive" unit, has controllable residual magnetism, and can generate the required field distribution with a very small volume, avoiding the heat problem and space occupation problem caused by the energization of the electromagnetic coil.

[0046] According to an embodiment of the present invention, the sub-magnet in the cavity may be detachable, so that the sub-magnet may be freely set in the cavity of the permanent magnet or not, thereby realizing the adjustment of the magnetic field generated by a single permanent magnet. For example, the multiple cavities of each annular bracket include a first cavity and a second cavity, the first cavity and the second cavity are alternately arranged on a plane, the first cavity is filled with a sub-magnet, and the second cavity is an empty cavity. Moreover, the shape, quantity and position of the cavity of each permanent magnet on the frame can be freely set.

[0047] According to an embodiment of the present invention, the magnetic poles, shape, quantity, and magnetization direction of the sub-magnets in each permanent magnet can be freely set. For example, the cross-sectional shape of the cavity in the plane includes a square, a parallelogram, a trapezoid, or a prism, and the cross-sectional shape of the sub-magnet in the plane is the same as that of the cavity.

[0048] Figure 1E FIG. 2 shows a schematic diagram of a square sub-magnet according to an embodiment of the present invention. Figure 1E As shown, the structure of the present invention can accommodate sub-magnets of various shapes at the same time, such as sub-magnets with cross-sectional shapes such as square and trapezoidal shapes. On this basis, the permanent magnet of the present invention has a large degree of freedom in magnetic field design. By adjusting the splicing method and magnetization direction of the sub-magnets, a diversified configuration scheme of magnetic field strength and direction can be achieved for a single permanent magnet. Under the premise of being easier to assemble and disassemble, the requirements for the shape and number of sub-magnets are reduced, and the degree of freedom in design is increased. In addition, due to the convenience of disassembly and assembly, convenient pole replacement, high degree of freedom in magnetization direction design and number of gaps design, the magnetic field design can be flexible. By adjusting the position and magnetization direction of the permanent magnet sub-magnets and selecting suitable permanent magnetic materials, high-precision magnetic field regulation can be achieved.

[0049] Based on this, the flexibility of permanent magnet magnetic lens design is improved by decomposing the magnetic poles into multiple sub-magnets that can be freely combined and replaced. Each permanent magnet can be optimized and adjusted according to actual needs to ensure the uniformity and accuracy of the overall magnetic field distribution. Sub-magnets of different types and specifications can be selected according to the needs of different applications and flexibly combined to achieve different performance requirements in different usage scenarios.

[0050] According to the embodiment of the present invention, the present invention can also change the shape of the annular bracket, thereby changing the structure of the permanent magnet. Figure 1F shows a schematic diagram of a ring-shaped bracket with a fixing structure according to an embodiment of the present invention, Figure 1G A schematic diagram of a permanent magnet with a fixed structure according to an embodiment of the present invention is shown.

[0051] like Figure 1F and Figure 1G As shown, a permanent magnet may include two annular brackets, each of which may have a protruding fixing structure HS on a plane perpendicular to the first direction X. The fixing structure HS may be provided with a through hole extending in a direction perpendicular to the protruding direction of the fixing structure. After the two annular brackets are combined, screws may be provided in the through hole to obtain a complete permanent magnet.

[0052] According to an embodiment of the present invention, the plurality of permanent magnets can rotate counterclockwise or clockwise on a plane perpendicular to the first direction X, thereby changing the magnetic field distribution of the first magnetic field.

[0053] Figure 2 A schematic diagram showing the rotation of a permanent magnet according to an embodiment of the present invention is shown.

[0054] like Figure 2 As shown, taking permanent magnet 200-1 and permanent magnet 200-2 as an example, permanent magnet 200-1 is located in the inner ring area of ​​permanent magnet 200-2. After permanent magnet 200-1 and permanent magnet 200-2 rotate, the relative position relationship between the sub-magnets of permanent magnet 200-1 and permanent magnet 200-2 will change, so that the magnetic field distribution of the first magnetic field can be adjusted. A plurality of balls can be arranged between permanent magnet 200-1 and permanent magnet 200-2 to facilitate the rotation of permanent magnet 200-1 and permanent magnet 200-2 relative to each other.

[0055] However, the embodiments of the present invention are not limited thereto. In other embodiments of the present invention, the permanent magnet may be provided with a cavity filled with sub-magnets and a cavity not filled with sub-magnets at the same time. Thus, after the permanent magnet rotates, the positional correspondence between the cavity of a certain permanent magnet and the sub-magnets of other permanent magnets can be changed. For example, the cavity of permanent magnet A and the cavity of permanent magnet B are arranged in a first direction X, and after at least one of permanent magnet A and permanent magnet B rotates, the cavity of permanent magnet A and the sub-magnet of permanent magnet B are arranged along the first direction X, or the sub-magnet of permanent magnet A and the cavity of permanent magnet B are arranged along the first direction X, or the sub-magnet of permanent magnet A and the sub-magnet of permanent magnet B are arranged along the first direction X, or the sub-magnet of permanent magnet A and the sub-magnet of permanent magnet B are arranged along the first direction X, and so on.

[0056] According to an embodiment of the present invention, at least one sub-magnet includes at least one first sub-magnet. Each first sub-magnet is simultaneously filled in the respective cavities of at least two permanent magnets in a plurality of permanent magnets, so that at least two permanent magnets are connected to each other. At least two permanent magnets include a first permanent magnet and a second permanent magnet adjacent to each other in a first direction X, and the first permanent magnet and the second permanent magnet can be relatively displaced relative to each other in the first direction X. At least one sub-magnet also includes at least one second sub-magnet, and each second sub-magnet is only arranged in the cavity of one permanent magnet. The magnetic pole of the second sub-magnet in the first permanent magnet close to one side of the second permanent magnet is the first magnetic pole, and the magnetic pole of the second sub-magnet in the second permanent magnet close to one side of the first permanent magnet is the second magnetic pole, and the first magnetic pole is opposite to the second magnetic pole.

[0057] Figure 3 A schematic diagram of permanent magnets connected via a first sub-magnet according to an embodiment of the present invention is shown.

[0058] like Figure 3As shown, the first sub-magnet 310 can be arranged in the respective cavities of the first permanent magnet 300-1 and the second permanent magnet 300-2, so that the first permanent magnet 300-1 and the second permanent magnet 300-2 are connected to each other. Further, the first permanent magnet 300-1 and the second permanent magnet 300-2 can be relatively displaced along the first direction X under the fixation of the first sub-magnet 310, so as to adjust the magnetic field distribution and the magnetic field peak of the first magnetic field. The side of the second sub-magnet 320 of the first sub-magnet 300-1 close to the second sub-magnet 330 of the second sub-magnet 300-2 can be the first magnetic pole (such as the N pole), and the side away from the second sub-magnet 330 can be the second magnetic pole (such as the S pole); the side of the second sub-magnet 330 close to the second sub-magnet 320 can be the second magnetic pole (such as the S pole), and the side away from the second sub-magnet 330 can be the first magnetic pole (such as the N pole). Thus, the first permanent magnet 300-1 and the second permanent magnet 300-2 can be used to apply a force to each other (for example, a magnetic force that attracts the first permanent magnet 300-1 and the second permanent magnet 300-2) through their respective second sub-magnets, so as to fix the original positional relationship between the first permanent magnet 300-1 and the second permanent magnet 300-2, for example, the first permanent magnet 300-1 and the second permanent magnet 300-2 are in contact with each other. On this basis, the first permanent magnet 300-1 and the second permanent magnet 300-2 can be separated from each other by applying a pulling force opposite to the above-mentioned magnetic force to the first permanent magnet 300-1 and the second permanent magnet 300-2, so as to adjust the magnetic field peak value and magnetic field distribution of the first magnetic field, and after canceling the above-mentioned pulling force, the first permanent magnet 300-1 and the second permanent magnet 300-2 can automatically return to the original positional relationship due to the attraction between the second sub-magnet 320 and the second sub-magnet 330. Wherein, the pulling force may be applied by a preset device, which is not limited here. The permanent magnet of the present invention may include a sub-magnet fixed in the cavity and a sub-magnet not fixed in the cavity at the same time. In some embodiments, when the second sub-magnet is subjected to force and the permanent magnet provided with the second sub-magnet is not subjected to force, the second sub-magnet may slide relative to the permanent magnet, and the second sub-magnet may be fixed in the permanent magnet by glue or other means.

[0059] According to an embodiment of the present invention, the first sub-magnet includes a protruding structure in a second direction intersecting with the first direction X, and the protruding structure is located between the first permanent magnet and the second permanent magnet to limit the range of relative displacement of the first permanent magnet and the second permanent magnet relative to each other.

[0060] Figure 4 A schematic diagram showing a protruding structure of a sub-magnet according to an embodiment of the present invention.

[0061] like Figure 4As shown, the protruding structure OS1 of the first sub-magnet 410 is between the first permanent magnet 400-1 and the second permanent magnet 400-2 in the first direction X, so that the first permanent magnet 400-1 and the second permanent magnet 400-2 can be prevented from being too close to each other, thereby achieving the effect of limiting the degree of change of the magnetic field distribution and magnetic field intensity of the first magnetic field. After the first sub-magnet 410 is used to connect the first permanent magnet 400-1 and the second permanent magnet 400-2, additional protruding structures can be bonded to the two ends of the first sub-magnet 410 in the first direction X to avoid the first permanent magnet 400-1 and the second permanent magnet 400-2 from being too far apart under the influence of tension, further achieving the limitation of the degree of change of the magnetic field distribution and magnetic field intensity of the first magnetic field. The second sub-magnet 420 and the second sub-magnet 430 can be provided with a protruding structure OS2 to fix the second sub-magnet 420. After the second sub-magnet is arranged, the end of the second sub-magnet in the first direction X where no protruding structure is arranged can also be bonded with an additional protruding structure to further fix the second sub-magnet.

[0062] According to an embodiment of the present invention, at least two permanent magnets include a third permanent magnet and a fourth permanent magnet, the outer diameter of the third permanent magnet is smaller than the inner diameter of the fourth permanent magnet, and the third permanent magnet can be relatively displaced relative to the fourth permanent magnet in the inner ring area of ​​the annular bracket of the fourth permanent magnet. The first sub-magnet includes two filling parts and a connecting part connecting the two filling parts. The two filling parts are respectively filled in the respective cavities of the third permanent magnet and the fourth permanent magnet, so that the third permanent magnet and the fourth permanent magnet are connected via the connecting part, and the connecting part is also used to limit the range of relative displacement of the third permanent magnet relative to the fourth permanent magnet in the inner ring area of ​​the annular bracket of the fourth permanent magnet.

[0063] Figure 5A shows a schematic diagram of a third permanent magnet and a fourth permanent magnet according to an embodiment of the present invention, Figure 5B Schematic diagram showing the relative displacement of the third permanent magnet and the fourth permanent magnet according to an embodiment of the present invention, Figure 5C A front view showing the relative displacement of the third permanent magnet and the fourth permanent magnet according to an embodiment of the present invention is shown.

[0064] like Figure 5A , Figure 5B and Figure 5CAs shown, the third permanent magnet 500-1 is in the inner ring area of ​​the fourth permanent magnet 500-2. Due to the constraint of the filling portion FS of the first sub-magnet 510, the third permanent magnet 500-1 and the fourth permanent magnet 500-2 can be relatively displaced along the filling portion FS in the first direction X, so that the magnetic field peak value and magnetic field distribution of the first magnetic field can be adjusted. Due to the constraint of the connecting portion CS of the first sub-magnet 520, the third permanent magnet 500-1 will be limited when it is displaced, so that the degree of change of the magnetic field peak value and magnetic field distribution of the first magnetic field can be limited. The displacement can be achieved based on the external force applied to the third permanent magnet 500-1 and the fourth permanent magnet 500-2 by the preset device, which is not limited here. After using the first sub-magnet 510 to connect the third permanent magnet 500-1 and the fourth permanent magnet 500-2, a protruding structure can be bonded to the two ends of the first sub-magnet 510 in the first direction X (that is, the ends of the filling portion FS in the first direction X) to further limit the third permanent magnet 500-1 and the fourth permanent magnet 500-1, thereby further limiting the degree of change in the magnetic field distribution and magnetic field intensity of the first magnetic field.

[0065] According to an embodiment of the present invention, the magnetic lens further comprises: an electromagnetic coil wound around an annular support in a clockwise or counterclockwise direction on the outer surface of an annular support, the electromagnetic coil being used to generate a second magnetic field, and the superimposed magnetic field formed by the first magnetic field and the second magnetic field being used to process the particle beam injected into the inner ring area. For example, the second magnetic field may be an adjustable magnetic field. The second magnetic field may be adjusted by adjusting the intensity of the current flowing through the electromagnetic coil. By setting the electromagnetic coil, the magnetic field intensity and shape may be dynamically adjusted by changing the current, so as to adapt to different exposure patterns of maskless electron beam exposure through fine modulation.

[0066] According to an embodiment of the present invention, the magnetic lens of the present invention is designed by the following method:

[0067] Step 1: Selection of permanent magnetic materials. The selection of permanent magnetic materials requires ensuring that the manufacturing process and magnetic properties of the materials meet the design requirements. The permanent magnetic materials of each sub-magnet must be selected accurately, and the magnetic properties of the materials must be matched to ensure the consistency of the overall magnetic field distribution.

[0068] Step 2: Consider the core parameters of the sub-magnet, such as the remanent magnetism, operating temperature range, Curie point, etc., and select the sub-magnet based on the actual working environment of the magnetic lens.

[0069] Step 3: Design the structure of the 3D (Dimensions) printing support frame based on the magnetization direction, magnet size, and number, and perform theoretical calculations to determine through numerical calculations whether the magnetic properties such as the axial field distribution of the designed sub-magnet combination meet the requirements.

[0070] Step 4: Control the 3D printing process and select the filament. 3D printing filaments are commonly used thermoplastics. For example, parameters such as the support strength of the filament can be used as evaluation indicators. For example, the filaments can be selected: PLA (polylactic acid), which is easy to print, suitable for low-temperature applications, and is often used for home and hobbyist projects; ABS (acrylonitrile butadiene styrene), which is high-strength and heat-resistant, and is often used to make functional parts; PETG (polyethylene terephthalate), which combines the ease of use of PLA and the strength of ABS, and is suitable for mechanical parts; TPU (thermoplastic polyurethane), which is soft and flexible, and is suitable for making impact-resistant and wear-resistant parts.

[0071] By using 3D printing technology to manufacture the annular bracket, the manufacturing and assembly process of the magnetic lens can be simplified, the complex processing steps can be reduced, and it is easy to implement. It also reduces the manufacturing and maintenance costs of the magnetic lens, improves the production efficiency of the magnetic lens, and makes replacement and upgrading more convenient.

[0072] Figure 6 A schematic diagram of a magnetic lens array according to an embodiment of the present invention is shown.

[0073] like Figure 6 As shown, the magnetic lenses of the present invention can be arranged in an array form. For application environments that require large-scale industrial manufacturing (such as maskless lithography and wafer direct writing), it is necessary to increase the amount of current carried by the charged particle beam, which is usually at the expense of limiting the resolution caused by the Coulomb interaction between the charged particles, and it is necessary to reduce the amplitude of the optical aberration introduced by the magnetic lens through other mechanisms for corresponding compensation. Based on the above-mentioned magnetic lens array, the total current delivered to the sample can be divided into multiple optical axes, which are respectively injected into the inner ring area of ​​each magnetic lens in the magnetic lens array, so as to be focused under the influence of the magnetic field. The splicable magnetic lens of the present invention can make it easier to design a multi-column system, and can overcome the limitations caused by the trade-off between current and optical aberration in a single-column system. On this basis, the current of the electron beam can be increased without sacrificing resolution through a multi-column design.

[0074] On this basis, the magnetic lens of the present invention can be combined with a miniaturized engineering application environment and applied to charged particle beam equipment, such as electron and ion microscopes, charged particle accelerators, electron beam processing machines, etc., so as to realize large-scale manufacturing of these equipment.

[0075] The magnetic lens of the present invention provides a new solution for high-precision electron beam applications such as micro-nano processing, semiconductor manufacturing and material analysis. Due to its flexibility, high-precision control capability and optimized structure, the magnetic lens of the present invention has a wide range of application potentials in modern electron beam technology. In the future, this technology is expected to play an important role in improving industrial production efficiency and scientific research accuracy.

[0076] It will be appreciated by those skilled in the art that the features described in the various embodiments of the present invention may be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, without departing from the spirit and teachings of the present invention, the features described in the various embodiments of the present invention may be combined and / or combined in various ways. All of these combinations and / or combinations fall within the scope of the present invention.

[0077] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination advantageously. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A magnetic lens, characterized in that: The magnetic lens comprises: A plurality of permanent magnets arranged coaxially; Each of the permanent magnets comprises an annular support and at least one sub-magnet, the structure of the annular support comprises a plurality of cavities, and the at least one sub-magnet is respectively filled in at least one cavity among the plurality of cavities; the annular support is manufactured by using three-dimensional printing technology; The plurality of permanent magnets are used to generate a first magnetic field, and the first magnetic field acts on the particle beam injected into the inner ring area of ​​the annular support; The at least two permanent magnets include a third permanent magnet and a fourth permanent magnet, the outer diameter of the third permanent magnet is smaller than the inner diameter of the fourth permanent magnet, and the third permanent magnet can be relatively displaced relative to the fourth permanent magnet in the inner ring area of ​​the annular support of the fourth permanent magnet; The at least one sub-magnet includes at least one first sub-magnet; the first sub-magnet includes two filling parts and a connecting part connecting the two filling parts; the two filling parts are respectively filled in the respective cavities of the third permanent magnet and the fourth permanent magnet, so that the third permanent magnet and the fourth permanent magnet are connected via the connecting part; The ends of the two filling parts are provided with protruding structures; the protruding structures and the connecting parts are used to jointly limit the range of relative displacement of the third permanent magnet relative to the fourth permanent magnet in the inner ring area of ​​the annular bracket of the fourth permanent magnet; The at least one sub-magnet further includes at least one second sub-magnet, each of the second sub-magnets is disposed in the cavity of only one permanent magnet, and the second sub-magnet is detachable during use of the magnetic lens.

2. The magnetic lens according to claim 1, characterized in that: Taking the central axis of the annular bracket as the axis of symmetry, the multiple cavities of each annular bracket are symmetrically distributed on a plane perpendicular to the axis of symmetry, and the multiple cavities of each annular bracket extend along a first direction, which is parallel to the extension direction of the central axis.

3. The magnetic lens according to claim 2, characterized in that: The cross-sectional shape of the cavity in the plane includes a square, a parallelogram, a trapezoid or a prism, and the cross-sectional shape of the sub-magnet in the plane is the same as that of the cavity.

4. The magnetic lens according to claim 2, characterized in that: The multiple cavities of each of the annular brackets include a first cavity and a second cavity, the first cavity and the second cavity are alternately arranged on the plane, the first cavity is filled with the sub-magnet, and the second cavity is a cavity.

5. The magnetic lens according to claim 1 or 2, characterized in that: The magnetic lens further comprises: An electromagnetic coil is wound around one of the annular supports in a clockwise or counterclockwise direction on the outer surface of the annular support, and the electromagnetic coil is used to generate a second magnetic field. The superimposed magnetic field formed by the first magnetic field and the second magnetic field is used to process the particle beam injected into the inner ring area.

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