Ion beam device for preventing sputtering pollution
By introducing electrostatic lens components and constrained magnetic field components into the ion beam device, the problem of ion sources being easily contaminated by sputtered particles is solved by using non-uniform electric field and high-strength magnetic field technology, and the stable performance and normal operation of the ion source are achieved.
Patent Information
- Application Number
- CN202420351064.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-26
- Publication Date
- 2025-04-15
- Estimated Expiration
- 2034-02-26
AI Technical Summary
In the prior art, ion sources are easily contaminated by partially sputtered returning particles, resulting in performance degradation or failure to function properly.
An ion beam device including an ion source, an electrostatic lens assembly and a constrained magnetic field assembly is designed. The electrostatic lens assembly converges the ion beam through a non-uniform electric field, and the constrained magnetic field assembly deflects the ion beam using a high-strength magnetic field to prevent it from returning to the ion source.
It effectively prevents contamination of ion sources, ensures the performance and normal operation of ion sources, and avoids the impact of diffuse magnetic fields on the ion beam and materials.
Smart Images
Figure CN222762922U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of ion source equipment, in particular to an ion beam device for preventing sputtering pollution. Background Art
[0002] An ion source is a device that ionizes neutral atoms or molecules to form plasma and extracts ions for acceleration. When the ion beam irradiates the surface of a material, its collision with the atoms on the surface of the material will produce a sputtering or injection effect. Therefore, ion sources are widely used in the semiconductor field, such as etching, thin film growth, ion implantation, etc.
[0003] However, when the ion beam is processing materials, some of the sputtered particles will return to the ion source, causing contamination of the ion source and reducing the performance of the ion source. If too much contaminant accumulates in the ion source, the ion source will not work properly. Therefore, it is necessary to provide an ion beam device that prevents sputtering contamination, which can solve the problem that the ion source in the prior art is easily contaminated by some of the sputtered particles. Summary of the invention
[0004] The utility model aims to provide an ion beam device capable of preventing sputtering pollution, which can solve the problem in the prior art that the ion source is easily polluted by particles returned by partial sputtering.
[0005] The utility model is achieved in this way:
[0006] An ion beam device for preventing sputtering pollution comprises an ion source, an electrostatic lens assembly and a confining magnetic field assembly; the ion source and the electrostatic lens assembly are coaxially arranged, and the ion beam outlet of the ion source faces the ion beam inlet of the electrostatic lens assembly; a high-intensity magnetic field is formed in the confining magnetic field assembly, one side of the confining magnetic field assembly forms an ion convergence inlet, the other side of the confining magnetic field assembly forms an ion beam expansion outlet, and an ion deflection path is formed between the ion convergence inlet, the ion beam focusing point and the ion beam expansion outlet; the ion beam outlet of the electrostatic lens assembly faces the ion convergence inlet of the confining magnetic field assembly, and the ion beam expansion outlet of the confining magnetic field assembly faces the material to be processed.
[0007] The electrostatic lens assembly comprises a first electrostatic lens electrode and a second electrostatic lens electrode; the first electrostatic lens electrode is connected to an external voltage source, the second electrostatic lens electrode is grounded, the ion source, the first electrostatic lens electrode, and the second electrostatic lens electrode are arranged in sequence at intervals; the first electrostatic lens electrode serves as the ion beam inlet of the electrostatic lens assembly, and the second electrostatic lens electrode serves as the ion beam outlet of the electrostatic lens assembly.
[0008] The first electrostatic lens electrode and the second electrostatic lens electrode are both annular structures, the ion source is a circular structure, and the ion source, the first electrostatic lens electrode and the second electrostatic lens electrode are coaxially arranged.
[0009] The outer diameter of the ring of the first electrostatic lens electrode is consistent with the outer diameter of the ring of the second electrostatic lens electrode and is larger than the diameter of the ion source. The inner diameter of the ring of the first electrostatic lens electrode is larger than the inner diameter of the ring of the second electrostatic lens electrode and smaller than the diameter of the ion source.
[0010] The confining magnetic field assembly comprises a permanent magnet and a yoke; the yoke is grounded, and a pair of permanent magnets are arranged at intervals in the yoke so that a high-intensity magnetic field is formed between the pair of permanent magnets through the yoke, and the axial direction of the pair of permanent magnets is perpendicular to the axial direction of the ion source and the electrostatic lens assembly; one side of the pair of permanent magnets forms an ion convergence entrance, and the other side of the pair of permanent magnets forms an ion beam expansion exit.
[0011] The angle between the line connecting the ion convergence inlet and the ion beam focusing point and the line connecting the ion beam expansion outlet and the ion beam focusing point is less than 180°.
[0012] A diaphragm is arranged at the focusing point of the ion beam.
[0013] The confinement magnetic field assembly comprises an electromagnet, a high-intensity magnetic field is formed between the two poles of the electromagnet, one side of the two poles of the electromagnet forms an ion convergence entrance, and the other side of the two poles of the electromagnet forms an ion beam expansion exit.
[0014] Compared with the prior art, the utility model has the following beneficial effects:
[0015] 1. The utility model is provided with a permanent magnet and a yoke iron. The yoke iron constrains the high-intensity magnetic field between a pair of permanent magnets, and no chaotic magnetic field is generated in the space, so that the ion beam can be deflected under the action of the Lorentz force when passing through the high-intensity magnetic field, and the movement path of the ion beam is changed and constrained, thereby avoiding ion sputtering back to the ion source when ions collide with the surface of the material and causing ion source contamination, thereby ensuring the performance and normal operation of the ion source, and also avoiding the influence of the diffuse magnetic field on the ion beam and the material.
[0016] 2. The utility model is provided with a first electrostatic lens electrode and a second electrostatic lens electrode, which use the first electrostatic lens electrode and the second electrostatic lens electrode with different inner diameters to generate a non-uniform electric field, so that the ion beam emitted by the ion source is converged into a high-intensity magnetic field, and expanded and emitted after passing through the high-intensity magnetic field, thereby ensuring uniform irradiation of the material surface. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a schematic diagram of the structure of the ion beam device for preventing sputtering pollution of the utility model;
[0018] Figure 2 It is a schematic diagram of the ion beam device for preventing sputtering contamination of the utility model;
[0019] Figure 3The utility model discloses a potential distribution diagram of a non-uniform electric field generated by an electrostatic lens assembly in an ion beam device for preventing sputtering pollution.
[0020] In the figure, 1 is an ion source, 2 is a first electrostatic lens electrode, 3 is a second electrostatic lens electrode, 4 is a permanent magnet, and 5 is a yoke. DETAILED DESCRIPTION
[0021] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments.
[0022] Please see attached Figure 1 and attached Figure 2 , an ion beam device for preventing sputtering pollution, comprising an ion source 1, an electrostatic lens assembly and a confining magnetic field assembly; the ion source 1 is coaxially arranged with the electrostatic lens assembly, and the ion beam outlet of the ion source 1 is arranged facing the ion beam inlet of the electrostatic lens assembly; a high-intensity magnetic field is formed in the confining magnetic field assembly, one side of the confining magnetic field assembly forms an ion convergence inlet, the other side of the confining magnetic field assembly forms an ion beam expansion outlet, and an ion deflection path is formed between the ion convergence inlet, the ion beam focusing point and the ion beam expansion outlet; the ion beam outlet of the electrostatic lens assembly is arranged facing the ion convergence inlet of the confining magnetic field assembly, and the ion beam expansion outlet of the confining magnetic field assembly is arranged facing the material to be processed.
[0023] Preferably, the ion source 1 may adopt a planar structure ion ejection device of the prior art, and the ion beam may be generated by electrostatically accelerating ions through plasma generated by gas discharge, thereby ejecting ions with a certain kinetic energy toward the electrostatic lens assembly.
[0024] The electrostatic lens assembly is used to converge the ion beam emitted from the ion source 1 to the ion beam focusing point, thereby increasing the consistency of the ion beam movement. The ion beam focusing point is located in the high-intensity magnetic field of the confining magnetic field assembly, so that the ion beam enters the high-intensity magnetic field through the ion convergence entrance. When the ion beam passes through the high-intensity magnetic field, it is deflected at the ion beam focusing point under the action of the Lorentz force, and then emitted from the ion beam expansion outlet after beam expansion, and can be evenly irradiated on the material to be processed, thereby realizing functions such as etching, thin film growth, and ion implantation.
[0025] During the collision between ions and atoms on the surface of the material, the charge is generally transferred to the material, and atoms or particles on the surface are sputtered out. Most of the particles produced by sputtering are not charged, and the deflection radius of low-speed charged particles in the high-intensity magnetic field is very small, so that the sputtered neutral particles or low-speed charged particles will accumulate in the confining magnetic field component, avoiding the sputtered particles from entering the ion source 1 and causing internal contamination of the ion source 1 and causing malfunctions. At the same time, because the ion beam is deflected when passing through the high-intensity magnetic field, that is, the movement direction of the ion beam is twisted and changed, the sputtered neutral particles or low-speed charged particles cannot return to the inside of the ion source 1, thereby avoiding the contamination of the ion source 1.
[0026] Please see attached Figure 1 To Attachment Figure 3 The electrostatic lens assembly includes a first electrostatic lens electrode 2 and a second electrostatic lens electrode 3; the first electrostatic lens electrode 2 is connected to an external voltage source, the second electrostatic lens electrode 3 is grounded, and the ion source 1, the first electrostatic lens electrode 2, and the second electrostatic lens electrode 3 are arranged in sequence at intervals; the first electrostatic lens electrode 2 serves as the ion beam inlet of the electrostatic lens assembly, and the second electrostatic lens electrode 3 serves as the ion beam outlet of the electrostatic lens assembly.
[0027] The first electrostatic lens electrode 2 maintains a specific voltage through a voltage source, and its voltage value can be adaptively adjusted according to actual use requirements, so that a non-uniform electric field is generated between the first electrostatic lens electrode 2 and the second electrostatic lens electrode 3. Figure 3 As shown, the ion beam is focused by using a non-uniform electric field, so that the ion beam is converged to the ion beam focusing point and diverges. At the same time, the ion beam focusing point is located in a high-intensity magnetic field, which can make the ion beam complete the movement path deflection, convergence and beam expansion when passing through the high-intensity magnetic field.
[0028] Preferably, the first electrostatic lens electrode 2 and the second electrostatic lens electrode 3 can adopt optical lenses (such as single lens Einzel lens, etc.), which can focus the ion beam at the ion beam focusing point in the high-intensity magnetic field, and diffusely emit the high-intensity magnetic field after passing through the ion beam focusing point, so that the ion beam can be evenly irradiated on the surface of the material.
[0029] Please see attached Figure 1 and attached Figure 2 The first electrostatic lens electrode 2 and the second electrostatic lens electrode 3 are both annular structures, the ion source 1 is a circular structure, and the ion source 1, the first electrostatic lens electrode 2 and the second electrostatic lens electrode 3 are coaxially arranged to ensure uniform convergence of the ion beam.
[0030] Please see attached Figure 1 To Attachment Figure 3 The outer diameter of the ring of the first electrostatic lens electrode 2 is consistent with the outer diameter of the ring of the second electrostatic lens electrode 3 and is larger than the diameter of the ion source 1. The inner diameter of the ring of the first electrostatic lens electrode 2 is larger than the inner diameter of the ring of the second electrostatic lens electrode 3 and is smaller than the diameter of the ion source 1.
[0031] The ion beam emitted from the ion source 1 is converged for the first time when passing through the first electrostatic lens electrode 2 , and is converged for the second time when passing through the second electrostatic lens electrode 3 , so that the ion beam can be converged to the ion beam focusing point in the high-intensity magnetic field.
[0032] The confining magnetic field assembly includes a permanent magnet 4 and a yoke 5; the yoke 5 is grounded, and a pair of permanent magnets 4 are arranged at intervals in the yoke 5, so that a high-intensity magnetic field is formed between the pair of permanent magnets 4 through the yoke 5, and the axial direction of the pair of permanent magnets 4 is perpendicular to the axial direction of the ion source 1 and the electrostatic lens assembly (that is, the axial direction of the first electrostatic lens electrode 2 and the axial direction of the second electrostatic lens electrode 3); one side of the pair of permanent magnets 4 forms an ion convergence entrance, and the other side of the pair of permanent magnets 4 forms an ion beam expansion exit.
[0033] The yoke 5 is made of a magnetic conductive material and is used to guide the magnetic field, which can enhance the magnetic field strength between the pair of permanent magnets 4, thereby forming a high-intensity magnetic field between the pair of permanent magnets 4. The magnetization direction of the pair of permanent magnets 4 is along their axis, so that the ion beam can be deflected when passing through the high-intensity magnetic field under the action of the Lorentz force. The permanent magnet 4 and the yoke 5 can be adaptively selected according to the intensity requirement of the high-intensity magnetic field.
[0034] Please see attached Figure 2 The angle between the line connecting the ion convergence entrance and the ion beam focusing point and the line connecting the ion beam expansion exit and the ion beam focusing point is less than 180°.
[0035] Preferably, the angle between the line connecting the ion convergence entrance and the ion beam focusing point and the line connecting the ion beam expansion exit and the ion beam focusing point is 90°, so that after the ion beam enters the high-intensity magnetic field from the ion convergence entrance, the motion path is deflected to the maximum extent under the action of the Lorentz force, and is ejected onto the surface of the material through the ion beam expansion exit, which can prevent the sputtered ions from directly returning to the ion source 1 and contaminating the ion source 1. The ions at the sputtering location can only return to the high-intensity magnetic field, and are constrained by the high-intensity magnetic field and cannot deflect the motion path back to the ion source 1, which effectively avoids contamination of the ion source 1.
[0036] By adjusting the strength of the high-intensity magnetic field and the kinetic energy of the ion beam, different Lorentz forces can be generated, allowing the ion beam to move at different deflection angles, thereby achieving the purpose of constraining the movement path of the ion beam.
[0037] An aperture (not shown in the figure) is provided at the focusing point of the ion beam, which can be used to block the ions sputtered when the ion beam is irradiated to the surface of the material, further preventing the sputtered ions from returning to the ion source 1 and causing contamination therein, thereby ensuring the stable performance of the ion source 1.
[0038] The confinement magnetic field assembly includes an electromagnet (not shown in the figure), and a high-intensity magnetic field is formed between the two poles of the electromagnet. One side of the two poles of the electromagnet forms an ion convergence entrance, and the other side of the two poles of the electromagnet forms an ion expansion exit.
[0039] An electromagnet is a yoke iron with a coil wound around it. When the coil is energized, a high-intensity magnetic field is generated between the two poles of the electromagnet. The strength of the magnetic field can be adaptively adjusted according to the current flowing through the coil.
[0040] Please see attached Figure 1 To Attachment Figure 3 , Example 1:
[0041] The ion source 1 with a diameter of 200mm emits an Ar ion beam, and the kinetic energy of the Ar ion beam is 1500eV. The first electrostatic lens electrode 2 is positively charged with 1000V, the inner diameter of the first electrostatic lens electrode 2 is 200mm, and the outer diameter of the first electrostatic lens electrode 2 is 300mm. The second electrostatic lens electrode 3 and the yoke 5 are grounded, the inner diameter of the second electrostatic lens electrode 3 is 100mm, and the outer diameter of the second electrostatic lens electrode 3 is 300mm. After magnetization, the magnetization intensity of the permanent magnet 4 is 0.5T, the spacing is 300mm, and the relative magnetic permeability of the yoke 5 is 400. In this case, the magnetic field strength between the permanent magnets 4 can reach 2000Oe.
[0042] The ion source 1, the first electrostatic lens electrode 2, and the second electrostatic lens electrode 3 are coaxially arranged; the axial direction of a pair of permanent magnets 4 is perpendicular to the ion source 1, the axial direction of the first electrostatic lens electrode 2, and the axial direction of the second electrostatic lens electrode 3. The setting direction of the yoke 5 has no effect on the simulation results, and the yoke 5 can be set according to actual needs. In this embodiment, the angle between the setting direction of the yoke 5 and the axial direction of the ion source 1 is 45°.
[0043] The Ar ion beam converges after passing through the non-uniform electric fields of the first electrostatic lens electrode 2 and the second electrostatic lens electrode 3, and enters the high-intensity magnetic field between a pair of permanent magnets 4 through the ion convergence entrance. During the simulation process, different Lorentz forces can be generated by adjusting the intensity of the high-intensity magnetic field and the kinetic energy of the ion beam, and the ion beam focusing point is located in the high-intensity magnetic field, so that the Ar ion beam is just deflected 90° when passing through the ion beam focusing point position in the high-intensity magnetic field, which can avoid the ion beam returning to the ion source 1 to the greatest extent. At the same time, the ion beam is expanded at the ion beam focusing point position and then ejected through the ion beam expansion outlet, and evenly irradiated on the surface of the material to be processed.
[0044] Ion beams can be converged to a focal point under the action of a non-uniform electric field and then expanded, and ion beams can be deflected in a magnetic field due to the Lorentz force. These are well-known technologies in the art, and their principles will not be described in detail here.
[0045] From the simulation results, it can be seen that the high-intensity magnetic field can be constrained by the yoke 5 between a pair of permanent magnets 4, and no chaotic magnetic field is generated in the space. When the ion beam enters the high-intensity magnetic field after being converged by the non-uniform electric field, it is deflected 90° at the focusing point of the ion beam under the action of the Lorentz force, and the beam is expanded and emitted to the surface of the material, which can avoid the influence of ion sputtering on the ion source and the influence of the diffuse magnetic field on the ion beam and the material.
[0046] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. An ion beam device for preventing sputtering contamination, characterized in that: The invention comprises an ion source (1), an electrostatic lens assembly and a confining magnetic field assembly; the ion source (1) and the electrostatic lens assembly are coaxially arranged, and the ion beam outlet of the ion source (1) is arranged facing the ion beam inlet of the electrostatic lens assembly; a high-intensity magnetic field is formed in the confining magnetic field assembly, one side of the confining magnetic field assembly forms an ion convergence inlet, and the other side of the confining magnetic field assembly forms an ion beam expansion outlet, and an ion deflection path is formed between the ion convergence inlet, the ion beam focusing point and the ion beam expansion outlet; the ion beam outlet of the electrostatic lens assembly is arranged facing the ion convergence inlet of the confining magnetic field assembly, and the ion beam expansion outlet of the confining magnetic field assembly is arranged facing the material to be processed.
2. The ion beam device for preventing sputtering contamination according to claim 1, characterized in that: The electrostatic lens assembly comprises a first electrostatic lens electrode (2) and a second electrostatic lens electrode (3); the first electrostatic lens electrode (2) is externally connected to a voltage source, the second electrostatic lens electrode (3) is grounded, and an ion source (1), the first electrostatic lens electrode (2), and the second electrostatic lens electrode (3) are sequentially arranged at intervals; the first electrostatic lens electrode (2) serves as an ion beam inlet of the electrostatic lens assembly, and the second electrostatic lens electrode (3) serves as an ion beam outlet of the electrostatic lens assembly.
3. The ion beam device for preventing sputtering contamination according to claim 2, characterized in that: The first electrostatic lens electrode (2) and the second electrostatic lens electrode (3) are both annular structures, the ion source (1) is a circular structure, and the ion source (1), the first electrostatic lens electrode (2) and the second electrostatic lens electrode (3) are coaxially arranged.
4. The ion beam device for preventing sputtering contamination according to claim 2 or 3, characterized in that: The outer diameter of the circular ring of the first electrostatic lens electrode (2) is consistent with the outer diameter of the circular ring of the second electrostatic lens electrode (3) and is larger than the diameter of the ion source (1); the inner diameter of the circular ring of the first electrostatic lens electrode (2) is larger than the inner diameter of the circular ring of the second electrostatic lens electrode (3) and is smaller than the diameter of the ion source (1).
5. The ion beam device for preventing sputtering contamination according to claim 1, characterized in that: The confining magnetic field assembly comprises a permanent magnet (4) and a yoke (5); the yoke (5) is grounded, and a pair of permanent magnets (4) are arranged at intervals in the yoke (5) so that a high-intensity magnetic field is formed between the pair of permanent magnets (4) through the yoke (5); the axial direction of the pair of permanent magnets (4) is perpendicular to the axial direction of the ion source (1) and the electrostatic lens assembly; one side of the pair of permanent magnets (4) forms an ion convergence entrance, and the other side of the pair of permanent magnets (4) forms an ion beam expansion exit.
6. The ion beam device for preventing sputtering contamination according to claim 5, characterized in that: The angle between the line connecting the ion convergence inlet and the ion beam focusing point and the line connecting the ion beam expansion outlet and the ion beam focusing point is less than 180°.
7. The ion beam device for preventing sputtering contamination according to claim 6, characterized in that: A diaphragm is arranged at the focusing point of the ion beam.
8. The ion beam device for preventing sputtering contamination according to claim 1, characterized in that: The confinement magnetic field assembly comprises an electromagnet, a high-intensity magnetic field is formed between the two poles of the electromagnet, one side of the two poles of the electromagnet forms an ion convergence entrance, and the other side of the two poles of the electromagnet forms an ion beam expansion exit.