A radio frequency ion source ion beam diameter restrainer, beam diameter control device and method

Abstract

The present invention relates to a radio frequency ion source ion beam diameter restraint, characterized in that: the beam diameter restraint comprises a base having a hollow structure through which the ion beam can pass, a plurality of blades and a driving mechanism; the plurality of blades are arranged at one end of the base and are arranged in a circle around the hollow structure, the tail ends of the plurality of blades extend into the area where the hollow structure is located to enclose and form an aperture through which the ion beam can pass, and the driving mechanism can drive the tail ends of the blades to move relative to the center of the circle formed by the blade arrangement to adjust the size of the aperture. The present invention also relates to a control device including a beam diameter restraint and a corresponding method, which is used to control the beam diameter of the ion beam, is easy to operate, has good adjustment accuracy, high efficiency, and is cost-saving.

Description

Technical Field

[0001] The invention relates to the technical field of ion beam sputtering coating and ultra-precision polishing, and in particular to a radio frequency ion source ion beam diameter restrainer, a beam diameter control device and a method. Background Art

[0002] In the research of ion beam ultra-precision machining, the ion source plays a very important role. The ion source is a device that generates ion beam flow and is also a key component in the ion beam equipment. Whether it is the preparation of optical thin films or nanoscale ion beam etching and polishing, high-performance ion beam flow is indispensable. The ion beam sources currently used mainly include Kaufman ion source, microwave ECR ion source and radio frequency ion source. Their working principle is to use gas discharge to generate plasma. The plasma is composed of electrons, ions and neutral particles, and is drawn out into a beam to become an ion source.

[0003] The radio frequency ion source was developed by Professor HW Loeb of the University of Giessen in Germany in the 1960s, expanding from electric rocket space applications to ground applications. This ion source has the advantages of simple structure and electrodeless discharge, so it has the characteristics of long life and high efficiency for any gas, especially reactive gas. The film layer plated with the radio frequency ion source has the advantages of less absorption, small drift, high efficiency, good density, and high firmness; at the same time, radio frequency ion source ion beam polishing is also widely used in the final processing of ultra-precision optical components. It is a polishing technology with atomic-level removal accuracy. It is considered to be the optical component shaping technology with the highest processing accuracy and the best shaping effect. In this process, an ion beam with a certain energy and spatial distribution bombards the surface of the optical component, and uses the physical sputtering effect that occurs during the bombardment to remove the surface material of the optical component to achieve the purpose of correcting the surface error. Its processing accuracy reaches the nanometer level.

[0004] The radio frequency (RF) ion source uses magnetic induction to generate plasma, so it is a non-polar discharge. The tungsten filament in the discharge chamber serves as the cathode. The tungsten filament can work for a long time in the reaction gas, greatly reducing the pollution to the ion beam. Since there are only single-charged ions and almost no double-charged ions in the plasma generated by radio frequency induction, the pollution caused by screen grid sputtering is particularly small, and the uniformity of the ion beam is also increased. The RF radio frequency ion source uses a special three-grid ion optical system, which not only improves the extraction efficiency, but also ensures the thermal stability of the structure and the reliability of anti-pollution.

[0005] When the ion source is working, the gas passes through the quartz discharge chamber and is discharged by 13.56MHz radio frequency power to ionize the gas to generate plasma. The charged particles are accelerated by the electrostatic field, the ion beam voltage is controlled, the discharge chamber power is increased, the discharge plasma concentration is increased, and the ion beam with a certain energy is formed after being focused and accelerated by the ion three-grid optical system.

[0006] In the prior art, the ion beam diameter of the radio frequency ion source is adjusted by the position and shape of the three-stage grid design located inside the ion source. During adjustment, the grid needs to be replaced repeatedly to achieve the beam diameter adjustment, which has low adjustment efficiency. At the same time, the existing grids are all curved grids, such as Figure 1 As shown, the processing and manufacturing are relatively difficult, and it is difficult to ensure the processing accuracy of the curved surface curvature and the aperture, and the processing cost is high. Summary of the invention

[0007] In view of the above problems, an object of the present invention is to provide a radio frequency ion source ion beam diameter restraint which is convenient for adjusting the beam diameter.

[0008] Another object of the present invention is to provide a beam diameter control device that facilitates beam diameter adjustment.

[0009] Another object of the present invention is to provide a beam diameter control method.

[0010] In order to achieve the above object, the technical solution of the present invention is: a radio frequency ion source ion beam diameter confinement device, characterized in that:

[0011] The beam diameter restrainer comprises a base having a hollow structure through which the ion beam can pass, a plurality of blades and a driving mechanism;

[0012] The multiple blades are arranged at one end of the base and in a circle around the hollow structure. The tail ends of the multiple blades extend into the area where the hollow structure is located to enclose an aperture through which the ion beam can pass. The driving mechanism can drive the tail ends of the blades to move relative to the center of the circle formed by the blade arrangement to adjust the size of the aperture.

[0013] Furthermore, the head ends of the blades are rotatably connected to the corresponding end faces of the base, and the tail ends of the blades are stacked in sequence along the circumference of the circle formed by the arrangement of the blades and extend obliquely into the area where the hollow structure is located to form the aperture;

[0014] The driving mechanism includes a slip ring and a driving assembly that drives the slip ring to rotate around the center of the slip ring. The slip ring is located on the side of the multiple blades away from the base and is coaxially arranged with the circumference formed by the multiple blades. When the slip ring rotates, the tail end of the blade is driven to rotate around the head end of the blade to achieve aperture size adjustment.

[0015] Furthermore, the blades are in the shape of an arc that is curved in the same direction as the circumference formed by the arrangement of the multiple blades.

[0016] Furthermore, a plurality of positioning holes arranged in a circumference are provided on the end surface of the one end of the base, and a fixed shaft which can be inserted into the positioning hole and rotated is provided on a side surface of the head end of the blade close to the base.

[0017] Furthermore, a guide column is provided on one side of the blade away from the base and is closer to the tail end of the blade than the fixed axis. The slip ring is provided with a guide groove in which the guide column can slide to drive the tail end of the blade to rotate around the head end of the blade when the slip ring rotates. The guide groove is arranged in an arc shape.

[0018] Furthermore, a gear ring is provided on the outer periphery of the slip ring, and the driving assembly includes a gear that can mesh with the gear ring and a servo motor that drives the gear to rotate.

[0019] A radio frequency ion source ion beam diameter control device, characterized in that:

[0020] The invention comprises a vacuum chamber, a controller, an ion beam generator, a beam diameter constrainer and a driver arranged in the vacuum chamber. The beam diameter constrainer is arranged at the front end of the ion beam generator. The driver is connected with the driving mechanism of the beam diameter constrainer to control the action of the driving mechanism. The controller is connected with the beam diameter constrainer and the driver respectively.

[0021] Furthermore, the ion beam generator includes an outer wall of the ion beam generator and a planar grid located inside the outer wall of the ion beam generator and at the front end of the ion beam.

[0022] Furthermore, the driver is a micro motor.

[0023] A method for controlling the beam diameter of an ion beam of a radio frequency ion source, characterized in that:

[0024] S1, evacuating the vacuum chamber;

[0025] S2, turn on the ion beam generator and adjust the voltage and current parameters;

[0026] S3, inputting the ion beam diameter value in the input interface of the controller;

[0027] S4, click the execution button of the controller, the controller sends a command to the driver, and the driver controls the action of the driving mechanism;

[0028] S5, the driving assembly drives the slip ring to rotate and drives the guide post to slide in the guide groove, and the blades rotate around the fixed axis to make the aperture size consistent with the input ion beam diameter value.

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] The beam diameter constrainer of the present application drives the slip ring to rotate through a driving assembly so that the blades rotate to adjust the size of the aperture, and the adjustment is convenient and has high adjustment accuracy. When the beam diameter is adjusted using a beam diameter control device including the beam diameter constrainer, the aperture size can be adjusted by inputting the ion beam diameter value on the controller, without closing the ion source and opening the vacuum chamber, and the adjustment efficiency is high and the degree of automation is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of using a curved grid to adjust the beam diameter in the prior art.

[0032] Figure 2 This is a schematic diagram of the structure of the planar grid used in the ion beam in this application.

[0033] Figure 3 This is a schematic diagram of the beam diameter restraint structure in this application.

[0034] Figure 4 for Figure 3 Schematic diagram of the explosion.

[0035] Figure 5 for Figure 4 A further explosion diagram of .

[0036] Figure 6 This is a schematic diagram of the blade structure in this application.

[0037] Figure 7 Schematic diagram of the beam diameter control device in this application. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] like Figures 3 to 6 Shown is a structural schematic diagram of the beam diameter restraint of the present application. As shown in the figure, the RF ion source ion beam diameter restraint includes a base 1, a plurality of blades 2 and a driving mechanism. The base 1 is provided with a hollow structure 11 for the ion beam to pass through. The plurality of blades 2 are provided at one end of the base 1 and are arranged in a circle around the hollow structure 11 of the base 1, and the tail ends 22 of the plurality of blades 2 extend into the area enclosed by the hollow structure 11 to form an aperture 3 for the ion beam to pass through. The driving mechanism can drive the tail ends 22 of the blades 2 to move relative to the center of the circle formed by the blade arrangement, so that the size of the aperture 3 enclosed by the blades 2 can be adjusted, that is, the beam diameter of the ion beam can be adjusted.

[0040] As a preferred embodiment, the head end 21 of the blade 2 is rotationally connected to the corresponding end face of the base 1, and the tail end 22 of the blade 2 is stacked in sequence along the circumferential direction of the circle formed by the arrangement of the blades 2 and extends obliquely into the area where the hollow structure 11 is located to form an aperture 3. The driving mechanism includes a slip ring 41 and a driving component that drives the slip ring 41 to rotate around the center of the slip ring 41. The slip ring 41 is located on the side of the multiple blades 2 away from the base 1 and is coaxially arranged with the circle formed by the arrangement of the multiple blades 2. When the slip ring 41 rotates, it drives the tail end 22 of the blade 2 to rotate around the head end 21 of the blade 2 to achieve the size adjustment of the aperture 3. That is, when the slip ring 41 rotates, since the head end 21 of the blade 2 is rotationally connected to the end face of one end of the base 1, the center distance of the head end 21 of the blade 2 relative to the circumference formed by the blade 2 will not change, while the tail end 22 of the blade 2 will move relative to the center of the circumference formed by the arrangement of the blades 2, thereby changing the size of the aperture 3 formed by the intersection of the tail ends 22 of the blades 2. In order to make the shape of the aperture 3 closer to a circle, the blades 2 have an arc shape that is bent in the same direction as the arc direction of the circle formed by the arrangement of the blades 2. At the same time, when the number of blades 2 is greater, the shape of the aperture 3 is closer to a circle.

[0041] Specifically, a plurality of positioning holes 12 arranged in a circumference are provided on the end surface of the corresponding end of the base 1, and a fixed shaft 23 that can be inserted into the positioning hole 12 and rotated is provided on the side surface of the head end 21 of the blade 2 close to the base 1, that is, the rotation of the blade 2 is performed around the fixed shaft 23. Of course, the rotational connection between the blade 2 and the base 1 can also be other ways, such as providing a positioning hole on the blade 2 and providing a fixed shaft on the base 1; a guide column 24 is provided on the side surface of the blade 2 away from the base 1, and the setting position of the guide column 24 is relative to the fixed shaft 23 is close to the tail end 22 of the blade 2, and the slip ring 41 is provided with a guide groove 42 for the guide post 24 to extend into and slide therein and drive the tail end 22 of the blade 2 to rotate around the head end 21 of the blade 2 when the slip ring 41 rotates. Similarly, the guide post can also be set on the slip ring 41 and the guide groove can be set on the blade 2. At the same time, in order to make the size adjustment speed of the aperture 3 more uniform and stable when the slip ring 41 rotates, the guide groove 42 is set to an arc shape that is consistent with the bending direction of the arc shape of the blade 2, which can also make the appearance of the beam diameter restraint more beautiful.

[0042] As a preferred embodiment, a gear ring 43 is provided on the outer periphery of the slip ring 41, and the driving assembly includes a gear 44 that can mesh with the gear ring 43 and a servo motor 45 that drives the gear 44 to rotate, and the servo motor 45 can be fixed on the base 1. Of course, it is conceivable that the way to achieve the rotation of the slip ring 41 can also be other ways, such as using a belt, a chain combined with a motor, or providing an external thread on the outer periphery of the slip ring 41 and using a screw rod for driving.

[0043] like Figure 7As shown, a radio frequency ion source ion beam diameter control device involved in the present application specifically comprises a vacuum chamber 5, a controller 6, an ion beam generator 7, a beam diameter constrainer 0 and a driver 8 arranged in the vacuum chamber 5. The beam diameter constrainer 0 is a beam diameter constrainer 0 that uses a blade 2 to adjust the size of the aperture 3. The beam diameter constrainer 0 is arranged at the front end of the ion beam generator 7. The driver 8 is connected to the driving mechanism of the beam diameter constrainer 0 to control the action of the driving mechanism. The controller 6 is connected to the beam diameter constrainer 0 and the driver 8 respectively. In this embodiment, the vacuum degree of the vacuum chamber 5 is 5.0×10 -3 Pa, the driver 8 is a micro motor, the ion beam generator 7 includes an ion beam generator outer wall 71 and a plane grid 72 located inside the ion beam generator outer wall 71 and at the front end of the ion beam, the controller 6 is a computer, the Matlab control code is written in the computer, and the micro motor is started through the execution of the code program, and the driving mechanism is controlled, that is, the servo motor 45 is controlled, the servo motor 45 uses an absolute encoder for positioning, the servo motor 45 drives the gear 44 to rotate and drives the slip ring 41 to rotate through the gear ring 43, when the slip ring 41 rotates, the blade 2 is driven to rotate around the fixed shaft 23 through the guide groove 42, so that the aperture size of the diaphragm 3 formed by the intersection of the tail end 22 of the blade 2 changes, that is, the adjustment of the ion beam diameter is realized, and finally the aperture size information of the diaphragm 3 is fed back to the computer. When the beam diameter constrainer 0 adopts the setting direction in the attached figure, when the slip ring 41 rotates clockwise, the aperture of the diaphragm 3 decreases, and when the slip ring 41 rotates counterclockwise, the aperture of the diaphragm 3 increases.

[0044] The present application also relates to a method for controlling the beam diameter of an ion beam of a radio frequency ion source, that is, a method for controlling the beam diameter of an ion beam using the above-mentioned beam diameter control device, comprising the following steps:

[0045] S1, evacuating the vacuum chamber 5;

[0046] S2, turn on the ion beam generator 7 and adjust the voltage and current parameters;

[0047] S3, inputting the ion beam diameter value in the input interface of the controller 6;

[0048] S4, click the execution button of the controller 6, the controller 6 sends a command to the driver 8, and the driver 8 controls the action of the driving mechanism;

[0049] S5, the driving assembly drives the slip ring 41 to rotate and drives the guide post 24 to slide in the guide groove 42, and the blade 2 rotates around the fixed shaft 23 to make the size of the aperture 3 consistent with the input ion beam diameter value.

[0050] Here are the specific steps for polishing using this method:

[0051] 1. Turn on the power supply, water cooling device, working argon gas, etc. of the ion beam polishing system;

[0052] 2. Place the optical element and fix it with a suitable fixture;

[0053] 3. Evacuate the vacuum chamber to ensure the vacuum state of the experiment, and the pressure of the vacuum chamber must reach 5.0×10 -3 Pa or above;

[0054] 4. Turn on the ion source, also known as the ion beam generator, and adjust the voltage, current and other parameters of the ion source;

[0055] 5. Select the ion beam diameter according to the size of the polished component and the surface parameters after detection, and input the ion beam diameter parameters into the computer control interface of the controller;

[0056] 6. Click the execution button of the controller, the controller sends a command to the driver, and the driver controls the action of the driving mechanism;

[0057] 7. The servo motor drives the slip ring to rotate and drives the guide column to slide in the guide groove. The blade rotates around the fixed axis to make the aperture size consistent with the input ion beam diameter value;

[0058] 8. Control the ion beam to vertically enter the Faraday cup, and use the method of collecting data at equal intervals to perform a Faraday scanning experiment to determine the removal function;

[0059] 9. After completing the Faraday scanning experiment, perform an ion beam polishing experiment on the component;

[0060] 10. Use an interferometer to measure the surface shape of the optical component after the experiment until the optical component reaches the technical accuracy requirements.

[0061] Although embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A radio frequency ion source ion beam diameter restrainer, characterized in that: The beam diameter restrainer (0) comprises a base (1) having a hollow structure (11) through which the ion beam can pass, a plurality of blades (2) and a driving mechanism; The plurality of blades (2) are arranged at one end of the base (1) and are arranged in a circle around the hollow structure (11); the tail ends (22) of the plurality of blades (2) extend into the area where the hollow structure (11) is located to enclose an aperture (3) through which the ion beam can pass; and the driving mechanism can drive the tail ends (22) of the blades (2) to move relative to the center of the circle formed by the arrangement of the blades (2) to adjust the size of the aperture (3); The head ends (21) of the blades (2) are rotatably connected to the corresponding end faces of the base (1), and the tail ends (22) of the blades (2) are stacked in sequence along the circumferential direction of the circle formed by the arrangement of the blades (2) and extend obliquely into the area where the hollow structure (11) is located to form the aperture (3); The driving mechanism comprises a slip ring (41) and a driving component that drives the slip ring (41) to rotate around the center of the slip ring (41); the slip ring (41) is located on a side of the plurality of blades (2) away from the base (1) and is coaxially arranged with a circle formed by the arrangement of the plurality of blades (2); when the slip ring (41) rotates, it drives the tail end (22) of the blade (2) to rotate around the head end (21) of the blade (2) to achieve size adjustment of the aperture (3); A plurality of positioning holes (12) arranged in a circumferential manner are provided on the end surface of the base (1), and a fixed shaft (23) which can be inserted into the positioning hole (12) and rotated is provided on a side surface of the head end (21) of the blade (2) close to the base (1); A guide column (24) is provided on a side surface of the blade (2) away from the base (1), and is located closer to the tail end (22) of the blade (2) than the fixed shaft (23); a guide groove (42) is provided on the slip ring (41), into which the guide column (24) can slide, so as to drive the tail end (22) of the blade (2) to rotate around the head end (21) of the blade (2) when the slip ring (41) rotates; and the guide groove (42) is arranged in an arc shape; A gear ring (43) is provided on the outer periphery of the slip ring (41), and the drive assembly comprises a gear (44) capable of meshing with the gear ring (43) and a servo motor (45) for driving the gear (44) to rotate.

2. The beam diameter restraint according to claim 1, characterized in that: The blades (2) are in the shape of an arc that curves in the same direction as the circumference formed by the arrangement of the multiple blades (2).

3. A radio frequency ion source ion beam diameter control device, characterized in that: The invention comprises a vacuum chamber (5), a controller (6), an ion beam generator (7) arranged in the vacuum chamber (5), a beam diameter constrainer (0) and a driver (8) as claimed in claim 1 or 2, wherein the beam diameter constrainer (0) is arranged at the front end of the ion beam generator (7), the driver (8) is connected to the driving mechanism to control the action of the driving mechanism, and the controller (6) is connected to the beam diameter constrainer (0) and the driver (8), respectively.

4. The beam diameter control device according to claim 3, characterized in that: The ion beam generator (7) comprises an ion beam generator outer wall (71) and a plane grid (72) located inside the ion beam generator outer wall (71) and at the front end of the ion beam.

5. The beam diameter control device according to claim 3, characterized in that: The driver (8) is a micro motor.

6. A method for controlling the diameter of an ion beam of a radio frequency ion source, characterized in that: The beam diameter control device according to any one of claims 3 to 5 is used for control, comprising the following steps S1, evacuating the vacuum chamber (5); S2, turning on the ion beam generator (7) and adjusting the voltage and current parameters; S3, inputting the ion beam diameter value in the input interface of the controller (6); S4, clicking the execution button of the controller (6), the controller (6) sends a command to the driver (8), and the driver (8) controls the action of the driving mechanism; S5, the driving assembly drives the slip ring (41) to rotate and drives the guide column (24) to slide in the guide groove (42), and the blade (2) rotates around the fixed axis (23) so that the size of the aperture (3) is consistent with the input ion beam diameter value.

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