An ion beam focusing system

Abstract

This application discloses an ion focusing system, including a process chamber, and a beam ion source, an electro-lens assembly, and a support platform arranged sequentially from top to bottom within the process chamber; the process chamber is grounded; the electro-lens assembly includes multiple micro-electro-lenses, which are spliced ​​together to form an electro-lens array; the electro-lens array is a downwardly curved surface and is rotationally symmetrical; the electro-lens assembly is connected to a first negative pressure V1; the support platform is connected to a second negative pressure V2 to form an electric field between the platform and the electro-lens assembly, where V2 < V1 < 0; after the plasma generated by the beam ion source passes through the electro-lens assembly, the positive ions in it are focused towards the central region of the electro-lens assembly under the action of the electric field, and the central region is a circular region centered on the rotation axis and located on the support platform. This ion focusing system, based on the principles of calculus, can improve the focusing effect of ions, and the diameter of the focused ion beam can reach within 10 mm.

Description

Technical Field

[0001] This application relates to the field of microfabrication technology, specifically to an ion beam focusing system. Background Technology

[0002] Ion beam-based additive manufacturing technology can directly write the structure and pattern of materials without an external heat source, thus significantly reducing the stress in the prepared materials. However, high-current ion beams generally exhibit divergence and are severely pulled by electrons within the beam, making focusing difficult.

[0003] Magnetic lenses are a commonly used focusing technique that uses confined electrons to pull ions, achieving the focusing of high-current ion beams. However, because the Lorentz force does no work, magnetic lenses cannot provide energy to the ions, resulting in poor stability of the ion beam after passing through the lens. Once momentum is exchanged with the background gas, the beam may diverge again. Therefore, the focusing effect of magnetic lenses on high-current ion beams is limited. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides an ion beam focusing system that can improve the problem that existing magnetic lenses cannot provide momentum to ions, causing ions to potentially diverge again due to collisions after passing through the magnetic lens.

[0005] To solve the above-mentioned technical problems, in a first aspect, embodiments of this application provide an ion beam focusing system, including a process chamber, and a beam ion source, an electric lens assembly, and a support platform arranged sequentially from top to bottom within the process chamber;

[0006] The process chamber is grounded;

[0007] The electro-lens assembly includes multiple micro-electro-lenses, which are spliced ​​together to form an electro-lens array; the electro-lens array is a downwardly curved surface and is rotationally symmetrical; the electro-lens assembly is connected to a first negative pressure V1;

[0008] The support platform is connected to a second negative pressure V2 to form an electric field with the electric lens assembly, and V2 < V1 < 0;

[0009] After the plasma generated by the beam ion source passes through the electric lens assembly, the positive ions therein are focused towards the central region of the electric lens assembly under the action of the electric field. The central region is a circular region located on the support platform with the rotation axis as the center.

[0010] Optionally, the longitudinal section of the electro-lens array is formed by connecting one or more of the following: circular arcs, elliptical arcs, hyperbolic segments, parabolic segments, and straight line segments; or,

[0011] The longitudinal section of the electro-lens array is formed by connecting one or more of the following: circular arc, elliptical arc, hyperbola segment, parabola segment, and straight line segment.

[0012] Optionally, the longitudinal section of the electro-lens array is arc-shaped; and;

[0013] The curvature of the electro-lens array is 0–100 m. -1 ; and / or, the diameter of the projection of the electro-lens array onto a plane perpendicular to the axial direction is 5 to 200 mm.

[0014] Optionally, the aperture of the micro-electro-lens is greater than or equal to 0.001 mm and less than or equal to twice the thickness s0 of the plasma sheath, wherein...

[0015]

[0016] In the formula, V0 is the potential of the micro-electro-lens, and T... e It is the electron temperature. It is the electronic Debye length.

[0017] Optionally, the aperture of the micro-electro-lens is 0.001–10 mm; and / or,

[0018] The aperture spacing between two adjacent micro-electro-lenses is 0.001 to 10 mm.

[0019] Optionally, the ion beam focusing system further includes a process chamber, in which the beam ion source, the electro-lens assembly, and the support platform are disposed, and the process chamber is grounded.

[0020] Optionally, the distance between the electro-lens assembly and the beam ion source is 10–300 mm; and / or,

[0021] The distance between the lower end of the electro-lens assembly and the support platform is 10–300 mm.

[0022] Optionally, at least two electro-lens assemblies are provided and arranged sequentially from the ion source to the support platform to form multi-level focusing.

[0023] Optionally, the ion beam processing equipment further includes a magnetic lens disposed within the process chamber;

[0024] The magnetic lens is arranged around the outside of the support platform and the electric lens assembly.

[0025] Optionally, the magnetic field strength of the magnetic lens gradually increases from top to bottom.

[0026] As described above, the ion focusing system of this application includes an electro-lens assembly comprising multiple micro-electro-lenses, all of which are spliced ​​together to form an electro-lens array. The electro-lens array is a rotationally symmetric shape. Negative pressures V1 and V2 are applied to the electro-lens assembly and the support platform, respectively, with V2 < V1 < 0, thereby creating an electric field between the support platform and the electro-lens assembly. Based on the concept of calculus, this application treats the irregular large-current ion beam as a large number of uniform micro-electro-parallel ion beams. A corresponding micro-electro-lens is set for each micro-electro-parallel ion beam. When the plasma passes through the aperture of the micro-electro-lens, electrons are repelled, while positive ions are attracted to pass through, thus obtaining a micro-electro-pure ion beam. Since the positive ions passing through the electro-lens assembly can be focused towards the central region of the electro-lens assembly under the action of the electric field, all micro-electro-pure ion beams are focused towards the central region of the electro-lens assembly. Furthermore, since the electro-lens array is a downward-curved surface, this shape can change the initial velocity and force direction of the positive ions when passing through the micro-electro-lens, enhancing the movement of ions towards the central region. The diameter of the focused ion beam can reach less than 10 mm, breaking through the limitations of the original technology. Therefore, the ion focusing system of this application can eliminate electronic interference, and at the same time enhance the movement of ions toward the central region based on the curved shape of the electron lens array, thereby improving the focusing effect of ions and thus obtaining a smaller focusing radius. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0028] Figure 1 This is a schematic diagram of the focusing principle of an existing electric lens;

[0029] Figure 2 This is a schematic diagram of the structure of an ion beam focusing system provided in an embodiment of this application;

[0030] Figure 3 This is a partial structural schematic diagram of an electro-lens assembly provided in an embodiment of this application;

[0031] Figure 4 This is a schematic diagram of the motion of charged particles provided in an embodiment of this application, wherein (a) is a schematic diagram of the motion of charged particles in the sheath fusion state, (b) is the simulation result of the motion of electrons in the sheath, and (c) is the simulation result of the motion of ions in the sheath;

[0032] Figure 5This is a simulation diagram of the process effect of the ion beam focusing system provided in the embodiments of this application, wherein (a) is an ion density distribution diagram; (b) is the deposition flux curve of ions on the substrate (r=0mm is the axis of symmetry Z);

[0033] Figure 6 This is a schematic diagram of an electro-lens assembly provided in an embodiment of this application, wherein (a) is a bottom view, (b) is a cross-sectional view along line AA in (a), and (c) is a partial view;

[0034] Figure 7 This is a schematic diagram of another ion beam focusing system provided in an embodiment of this application;

[0035] Figure 8 This is a schematic diagram of another ion beam focusing system provided in the embodiments of this application.

[0036] The realization of the objectives, functional features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0037] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0038] It should be further understood that the terms "comprising" or "including" indicate the presence of the stated features, steps, operations, elements, components, items, types, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, types, and / or groups. The terms "or," "and / or," and "comprising at least one of the following," as used in this application, can be interpreted as inclusive, or mean any one or any combination thereof. For example, "comprising at least one of the following: A, B, C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C," and similarly, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C." Exceptions to this definition only occur when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0039] It should be understood that although the terms first, second, third, etc., may be used in this document to describe various types of information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this document, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the singular forms “a,” “an,” and “the” used in this document are intended to also include the plural forms, unless the context indicates otherwise.

[0040] It should be understood that the terms "top", "bottom", "upper", "lower", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application.

[0041] For ease of description, the following embodiments are all illustrated using an orthogonal space defined by a horizontal plane and a vertical direction. This premise should not be construed as a limitation of this application.

[0042] As mentioned above, although magnetic lenses can focus large-current ion beams by confining electrons to pull ions, the ion beams are unstable after passing through the magnetic lens because the Lorentz force does no work and the magnetic lens cannot provide energy for the ions. Once momentum is exchanged with the background gas, the ion beams may diverge again.

[0043] To address the issue that magnetic lenses cannot provide energy to ions, electric lenses can be used to focus high-current ion beams, increasing ion energy through an electric field. The principle is as follows: Figure 1 As shown, a high-current diverging ion beam becomes a parallel beam after passing through an electric lens (aperture D is typically between 100-200 mm) 10a, and is then focused by the electric field E2 between the electric lens 10a and the support platform 20a. However, due to the large number of electrons in the high-current diverging ion beam, interference occurs with the ions, resulting in insufficient focusing of the ion beam. For example, the diameter of the focused ion beam from a 100 mm diameter high-current ion beam can only reach 50 mm. Based on this, this application provides an ion beam focusing system.

[0044] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of an ion beam focusing system provided in an embodiment of this application. The ion beam focusing system may include an electro-lens assembly 100, a process chamber 200, a support platform 300, and a beam ion source 400.

[0045] The process chamber 200 is grounded, which can shield the external influence on the internal focusing electric field and control the background vacuum level when the ion beam focusing system is working. For example, the vacuum level inside the process chamber 200 can be controlled to 10. -3 ~10 Pa, to reduce momentum exchange between the ion beam and the background gas.

[0046] As examples, the beam ion source 400 can be one or more of the following devices: planar cathode, cylindrical cathode, ring cathode, gas ion source, cathode arc, etc., and the discharge mode can be one or more of the following: DC discharge, pulse discharge, radio frequency discharge, intermediate frequency discharge, composite pulse discharge, high power pulse discharge.

[0047] Please also refer to Figure 2 and Figure 3 , Figure 3 This is a partial structural schematic diagram of an electro-lens assembly provided in an embodiment of this application. The electro-lens assembly 100 may include multiple micro-electro-lenses 10, all of which are spliced ​​together to form an electro-lens array. The electro-lens array is a downwardly curved surface and is rotationally symmetric. Figure 2 The Z-axis is the rotational symmetry axis of the electric lens array.

[0048] Specifically, each micro-electro-lens 10 may include an electrode 11 and a hole 12 disposed on the electrode 11. The electrode may be made of metal or other conductive materials. All micro-electro-lenses 10 are spliced ​​to form an electro-lens array. The splicing method and specific shape are not particularly limited in this embodiment, as long as the electro-lens array formed by splicing is rotationally symmetrical. Therefore, the electro-lens array may be formed by assembling and splicing independent micro-electro-lenses 10, or it may be formed by assembling multiple annular components, each annular component including multiple micro-electro-lenses 10; in other embodiments, the electro-lens array may also be integrally formed, for example, by 3D printing, die casting, or hot bending and stamping of sheet metal, etc. The electro-lens assembly is connected to the first negative pressure V1.

[0049] The support platform 300 is used to support the substrate 500. An electro-lens assembly 100 is disposed between the beam ion source 400 and the support platform 300. The support platform 300 is connected to a second negative voltage V2 to form an electric field with the electro-lens assembly 100, where V2 < V1 < 0, meaning the potential of the support platform 300 is lower than the potential of the electro-lens assembly 100. Positive ions from the electro-lens assembly 100 are focused into the central region of the electro-lens assembly 100 under the influence of this electric field. This central region is a circular area centered on the rotation axis Z and located on the support platform 300. The substrate 500 can be disposed in this central region to receive the focused ion beam, thereby enabling micromachining of the substrate 500. Ideally, the central region can also be the intersection of the rotation axis Z and the support platform 300; this point is referred to as the focal point in this application, and in this case, the diameter of the central region can be considered to be 0. It is understood that the central region is the target area for focusing, and the diameter of the central region can be adjusted according to the actual application.

[0050] This application, based on the concepts of calculus, treats the irregular, high-current ion beam as a large number of uniform, infinitesimal parallel ion beams, and sets up a corresponding infinitesimal electric lens 10 for each infinitesimal parallel ion beam. Please refer to... Figure 2 and Figure 4 , Figure 4 This is a schematic diagram of the motion of charged particles provided in an embodiment of this application. (a) is a schematic diagram of the motion of charged particles in the sheath fusion state, (b) is a simulation result of the motion of electrons in the sheath, and (c) is a simulation result of the motion of ions in the sheath. In application, the process chamber 200 can be grounded (potential is 0) to shield the external interference to the focusing system. Negative voltages V1 and V2 are applied to the electro-lens assembly 100 and the support platform 300 respectively, and V2 < V1 < 0, so that an electric field is formed between the support platform 300 and the electro-lens assembly 100. For example, V1 and V2 can be selected in the range of 0 to -10kV. All micro-electro-lenses 10 have a potential of V1. When plasma passes through the aperture 12 of the micro-electro-lens 10, electrons are repelled and positive ions are attracted, thus obtaining a micro-electro-pure ion beam. Because the positive ions passing through the electro-lens assembly 100 can be focused towards the central region of the electro-lens assembly 100 under the influence of the electric field, all micro-electro-pure ion beams are focused towards the central region of the electro-lens assembly 100. Furthermore, since the electro-lens array is a downward-curved surface, this shape can change the initial velocity and force direction of the positive ions when passing through the micro-electro-lens, enhancing the ion movement towards the central region. The diameter of the focused ion beam can reach less than 10 mm, meaning the diameter of the central region can be less than 10 mm, overcoming the limitations of existing technologies. Therefore, the ion focusing system of this application can eliminate electronic interference and, based on the curved shape of the electro-lens array, enhance the movement of ions towards the center, thus improving the ion focusing effect and achieving a smaller focusing radius.

[0051] As examples, the electro-lens array has a downwardly curved surface shape. For instance, the longitudinal section of the electro-lens array can be formed by connecting one or more curves such as circular arcs, elliptical arcs, hyperbolic segments, and parabolic segments, or by connecting at least one of the aforementioned curves with straight line segments. That is, the micro-element electro-lens 10 constituting the electro-lens array can be a spherical surface, elliptical surface, hyperboloid, parabolic surface, or at least one of the aforementioned surfaces combined with a plane. The term "combined" is merely to more accurately describe the inventive concept based on "calculus." In practical applications, the electro-lens array can be integrally formed. It is understood that the three-dimensional shape of the electro-lens array can be obtained by connecting one or more of the aforementioned line segments and then rotating them around one end.

[0052] As examples, the longitudinal section of the electron lens array is arc-shaped, and the curvature of the electron lens array is 0–100 m. -1 In this embodiment, the electron lens array is spherical. Furthermore, the diameter of the projection of the electron lens array onto a plane perpendicular to the axis can be 5–200 mm. By controlling the curvature of the arc array and the potential of the supporting platform 300, the micro-element pure ion beams exiting all the micro-element electron lenses 10 can be focused towards the central region of the electron lens array.

[0053] Preferably, the aperture of the micro-electro-lens is greater than 0.001 mm and less than twice the thickness s0 of the plasma sheath, wherein...

[0054]

[0055] In the formula, V0 is the potential of the micro-electro-lens, and T... e It is the electron temperature. It is the electronic Debye length. Where ε0 is the dielectric constant in vacuum, ε0 = 8.854 × 10⁻⁶ -12 F / m, k B It is the Boltzmann constant, k B =1.38×10 -23 J / K, T is the ambient temperature, n e This is the plasma density, and e is the charge of an electron, e = 1.6 × 10⁻⁶. -19 C.

[0056] As some examples, when surface treatment is typically performed using PVD technology to generate ion beams, the plasma density range is approximately 10. 16 ~10 22 m -3The electron temperature range is 1–10 eV. According to the above formula, the aperture of the micro-electro-lens 10 can be determined to be 0.001–10 mm. 10 mm ensures that the aperture of the micro-electro-lens is less than twice the thickness s0 of the plasma sheath. Furthermore, if the aperture is too small, it cannot be processed. Preferably, the aperture range is 0.05–5 mm, and more preferably, the aperture range is 0.1–1 mm. In addition, the aperture spacing between two adjacent micro-electro-lenses 10 can be 0.001–10 mm.

[0057] As examples, the distance between the electro-lens assembly 100 and the beam ion source 400 in the ion beam focusing system is 10 to 300 mm. If the distance is too small, the electro-lens assembly 100 will interfere with the beam ion source 400. If the distance is too large, it will result in a large loss of positive ions.

[0058] As examples, the distance between the lower end of the electro-lens assembly 100 and the support platform 300 can be 10 to 300 mm. If the distance is too small, the movement time of the ions is too short, and they cannot focus in time, resulting in poor focusing effect; if the distance is too large, it will result in a large loss of positive ions.

[0059] Please see Figure 5 , Figure 5 This is a simulation diagram of the process effect of the ion beam focusing system provided in the embodiments of this application, wherein (a) is an ion density distribution diagram; (b) is the deposition flux curve of ions on the substrate (r = 0 mm is the rotational symmetry axis Z). For the parameters of the electro-lens assembly used in the simulation, please refer to [link to relevant documentation]. Figure 6 , Figure 6 This is a schematic diagram of an electro-lens assembly provided in an embodiment of this application, wherein (a) is a bottom view, (b) is a cross-sectional view along line AA in (a), and (c) is a partial view. Specifically, the simulation conditions and parameters are as follows: the electro-lens assembly 100 is spherical with a thickness of 0.5 mm; the diameter of the projection circle of the electro-lens assembly 100 onto the plane perpendicular to the rotation axis is 140 mm; the diameter of the hole on the electro-lens assembly 100 is 0.3 mm; the center distance between two adjacent holes is 0.6 mm; the focal length (the distance between the central region and the center of the top surface of the electro-lens assembly 100) is 80 mm; a negative pressure of -100 V is applied to the electro-lens assembly 100; a negative pressure of -1500 V is applied to the bearing platform 300; and the plasma density is 10. -18 m -3 The distance between the beam ion source 400 and the electro-lens assembly 100 is 60 mm, and the distance between the electro-lens assembly 100 and the support platform 300 is 80 mm.

[0060] Depend on Figure 5It can be seen that the ion density exhibits a uniform distribution immediately after passing through the electron lens array. Under the influence of the focusing electric field between the electron lens assembly 100 and the support platform 300, the ions continuously focus towards the central axis Z during their movement. Ultimately, the ions exhibit extremely high deposition flux at the focal point (r = 0 mm) on the substrate. As the distance to the focal point increases, the ion deposition flux rapidly decreases, thus achieving high focusing of positive ions in a large ion beam. The ion beam diameter can be focused from 140 mm to below 4 mm.

[0061] In one embodiment, see Figure 7 , Figure 7 This is a schematic diagram of another ion beam focusing system provided in the embodiments of this application. At least two electro-lens assemblies 100 are provided and are arranged sequentially from the beam ion source 400 to the support platform 300 to form multi-stage focusing. Figure 7 Taking the example of setting up two electron lens assemblies 100A and 100B to form a two-stage focusing, electron lens assembly 100A initially focuses all micro-element ion beams onto electron lens assembly 100B. Electron lens assembly 100B further enhances the focusing of the micro-element ion beams by increasing their curvature, focusing them onto the substrate 500. This two-stage focusing allows for gradual focusing of the ion beam, making it suitable for ion beams with larger areas.

[0062] For example, the distance between the support platform 300 and the lower end of the electro-lens array can be 10 to 1000 mm. The size of the support platform 300 is smaller than the diameter of the projection of the electro-lens array onto a plane perpendicular to the axial direction (rotational symmetry axis Z). For example, the diameter of the support platform 300 can be 1 to 1000 mm.

[0063] As an example, the support platform 300 can be a flat plate structure, a porous structure, or a hollow grid structure, and the interior of the support platform 300 is an equipotential region. The substrate 500 can be placed on the surface of the support platform 300 (e.g., Figure 2 As shown), it can also be placed in the equipotential region inside the bearing platform 300 (such as...). Figure 8 The diameter of the focused ion beam can be adjusted by controlling the potential of the support platform 300. For example, the diameter of the focused ion beam can be increased, and the entire beam can be deposited onto the substrate 500 in parallel. The substrate 500 can be a structure of any shape, such as planar, arc-shaped, trapezoidal, or with protrusions or grooves. For example, the surface of the substrate 500 can have grooves located at the focal point of the electron lens array.

[0064] In one embodiment, see Figure 8 , Figure 8This is a schematic diagram of another ion beam focusing system provided in the embodiments of this application. The ion beam focusing system may also include a magnetic lens 600 disposed in the process chamber 200. The magnetic lens 600 is disposed around the outside of the support platform 300 and the electro-lens assembly 100. The magnetic lens can further enhance ion beam focusing.

[0065] Preferably, the magnetic field strength of the magnetic lens 600 gradually increases from top to bottom, that is, the magnetic field gradually increases along the ion beam output direction, with the magnetic field strength being greater near the support platform 300, which can improve the focusing accuracy of the ion beam. As an example, the magnetic field of the magnetic lens 600 can be generated by a coil, with the coil winding density increasing from top to bottom.

[0066] In some embodiments, the ion beam focusing system of this application can be used to perform functions such as sample cleaning, coating deposition, enhanced discharge, and direct writing of materials.

[0067] The ion beam focusing system provided in this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. It should be noted that the descriptions of each embodiment in this application have different emphases. Parts not described in detail or in a certain embodiment can be referred to the relevant descriptions of other embodiments.

[0068] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. The technical features of the technical solution of this application can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are also included within the patent protection scope of this application, as long as the combination of these technical features does not contradict each other.

Claims

1. An ion beam focusing system, characterized in that, It includes a process chamber, and a beam ion source, an electric lens assembly, and a support platform arranged sequentially from top to bottom within the process chamber; The process chamber is grounded; The electro-lens assembly includes multiple micro-electro-lenses, which are spliced ​​together to form an electro-lens array. The electro-lens array is a downward-curving surface and is rotationally symmetric. The electro-lens assembly is connected to the first negative voltage V1; The support platform is connected to a second negative pressure V2 to form an electric field with the electric lens assembly, and V2 < V1 < 0; After the plasma generated by the beam ion source passes through the electric lens assembly, the positive ions therein are focused towards the central region of the electric lens assembly under the action of the electric field. The central region is a circular region centered on the rotation axis and located on the support platform.

2. The ion beam focusing system according to claim 1, characterized in that, The longitudinal section of the electro-lens array is formed by connecting one or more of the following: circular arcs, elliptical arcs, hyperbolic segments, and parabolic segments; or, The longitudinal section of the electro-lens array is formed by connecting one or more of the following: circular arc, elliptical arc, hyperbola segment, parabola segment, and straight line segment.

3. The ion beam focusing system according to claim 2, characterized in that, The longitudinal cross-section of the electro-lens array is arc-shaped; and, The curvature of the electro-lens array is 0~100m. -1 ; and / or, the diameter of the projection of the electro-lens array onto a plane perpendicular to the axial direction is 5 to 200 mm.

4. The ion beam focusing system according to claim 1, characterized in that, The aperture of the micro-electro-lens is greater than or equal to 0.001 mm and less than or equal to twice the thickness s0 of the plasma sheath. In the formula, It is the electric potential of the micro-electro-lens. It is the temperature of the electrons. It is the electronic Debye length.

5. The ion beam focusing system according to claim 4, characterized in that, The aperture of the micro-electro-lens is 0.001~10mm; and / or, The aperture spacing between two adjacent micro-electro-lenses is 0.001~10mm.

6. The ion beam focusing system according to claim 1, characterized in that, The distance between the electro-lens assembly and the beam ion source is 10~300mm; and / or, The distance between the lower end of the electro-lens assembly and the support platform is 10~300mm.

7. The ion beam focusing system according to claim 1, characterized in that, The electro-lens assembly comprises at least two components, arranged sequentially from the ion source to the support platform to form multi-level focusing.

8. The ion beam focusing system according to any one of claims 1-7, characterized in that, It also includes a magnetic lens disposed within the process chamber; The magnetic lens is arranged around the outside of the support platform and the electric lens assembly.

9. The ion beam focusing system according to claim 8, characterized in that, The magnetic field strength of the magnetic lens gradually increases from top to bottom.

Images